Aarhus University is a public university located in Aarhus, Denmark. Founded in 1928, it is Denmark's second oldest university and the largest, with a total of 43,600 enrolled students as of 1 January 2012, after a merger with Aarhus School of Engineering. In most prestigious ranking lists of the world´s best universities, Aarhus University is placed in the top 100. The university belongs to the Coimbra Group of European universities.Denmark's first professor of sociology was a member of the faculty of Aarhus University , and in 1997 Professor Jens Christian Skou received the Nobel Prize in Chemistry for his discovery of the sodium-potassium pump. In 2010 Dale T. Mortensen, a Niels Bohr Visiting Professor at Aarhus University, received the Nobel Prize in Economic science together with his colleagues Peter Diamond and Christopher Pissarides. Wikipedia.
Lahteenmaki L.,University of Aarhus
Food Quality and Preference | Year: 2013
Health-related information is increasingly used on food products to convey their benefits. Health claims as a subcategory of these messages link the beneficial component, functions or health outcomes with specific products. For consumers, health claims seem to carry the message of increased healthiness, but not necessarily making the product more appealing. The wording of the claim seems to have little impact on claim perception, yet the health image of carrier products is important. From consumer-related factors the relevance and attitudes towards functional foods play a role, whereas socio-demographic factors have only minor impact and the impact seems to be case-dependent. Familiarity with claims and functional foods increase perceived healthiness and acceptance of these products. Apparently consumers make rather rational interpretations of claims and their benefits when forced to assess the information, but we still know relatively little about consumer understanding of the message content in claims and even less about the assessment of personal relevance of the claimed benefits. In future studies more emphasis should be put on including contextual influences and realistic conditions in assessing consumer understanding and use of health claims in purchase decisions. © 2012 Elsevier Ltd.
Nielsen S.B.,University of Aarhus |
Nielsen M.B.,Copenhagen University |
Rubio A.,University of the Basque Country
Accounts of Chemical Research | Year: 2014
ConspectusIn a charge-transfer (CT) transition, electron density moves from one end of the molecule (donor) to the other end (acceptor). This type of transition is of paramount importance in nature, for example, in photosynthesis, and it governs the excitation of several protein biochromophores and luminophores such as the oxyluciferin anion that accounts for light emission from fireflies. Both transition energy and oscillator strength are linked to the coupling between the donor and acceptor groups: The weaker the coupling, the smaller the excitation energy. But a weak coupling necessarily also causes a low oscillator strength possibly preventing direct excitation (basically zero probability in the noncoupling case). The coupling is determined by the actual spacer between the two groups, and whether the spacer acts as an insulator or a conductor. However, it can be difficult or even impossible to distinguish the effect of the spacer from that of local solvent molecules that often cause large solvent shifts due to different ground-state and excited-state stabilization. This calls for gas-phase spectroscopy experiments where absorption by the isolated molecule is identified to unequivocally establish the intrinsic molecular properties with no perturbations from a microenvironment. From such insight, the effect of a protein microenvironment on the CT excited state can be deduced.In this Account, we review our results over the last 5 years from mass spectroscopy experiments using specially designed apparatus on several charged donor-acceptor ions that are based on the nitrophenolate moiety and π-extended derivatives, which are textbook examples of donor-acceptor chromophores. The phenolate oxygen is the donor, and the nitro group is the acceptor. The choice of this system is also based on the fact that phenolate is a common structural motif of biochromophores and luminophores, for example, it is a constituent of the oxyluciferin anion. A presentation of the setups used for gas-phase ion spectroscopy in Aarhus is given, and we address issues of whether double bonds or triple bonds best convey electronic coupling between the phenolate oxygen and the nitro group, the significance of separating the donor and acceptor spatially, the influence of cross-conjugation versus linear conjugation, and along this line ortho versus meta versus para configuration, and not least the effect of a single solvent molecule (water, methanol, or acetonitrile). From systematic studies, a clear picture has emerged that has been supported by high-level calculations of electronically excited states. Our work shows that CC2 coupled-cluster calculations of vertical excitation energies are within 0.2 eV of experimental band maxima, and importantly, that the theoretical method is excellent in predicting the relative order of excitation energies of a series of nitrophenolates. Finally, we discuss future challenges such as following the change in absorption as a function of the number of solvent molecules and when gradually approaching the bulk limit. © 2014 American Chemical Society.
Holst N.,University of Aarhus
Ecological Informatics | Year: 2013
Software design is an often neglected issue in ecological models, even though bad software design often becomes a hindrance for re-using, sharing and even grasping an ecological model. In this paper, the methodology of agile software design was applied to the domain of ecological models. Thus the principles for a universal design of ecological models were arrived at. To exemplify this design, the open-source software Universal Simulator was constructed using C++ and XML and is provided as a resource for inspiration. © 2012 Elsevier B.V.
Elsgaard L.,University of Aarhus
Soil Biology and Biochemistry | Year: 2013
Ethylene (C2H4), which is a potent gaseous plant hormone, has often been found to accumulate in anoxic soils where pathways of anaerobic C2H4 oxidation are so far unknown and other C2H4 transformation processes are uncommon. The present study shows that ethylene was reduced almost stoichiometrically (89-92%) to ethane (C2H6) in peat-soil microcosms incubated under methanogenic conditions. Methanogenesis started after a prolonged anoxic lag-phase (>29 weeks) where added ethylene prevailed despite the availability of nitrate (NO3 -) as an alternative electron acceptor. Methanogenesis, as well as ethylene reduction to ethane, was inhibited by 90% at 1% oxygen. Likewise, methanogenesis and ethane formation was gradually inhibited (to a similar extent) by increasing ethylene concentrations above 0.2%; this inhibition eventually reached 90-95% at 2.2-4.5% C2H4. The present results extend the known settings for ethylene reduction to ethane, which has been occasionally reported for aquatic sediments. The importance of ethylene turn-over in anoxic peat-soils should be substantiated by studies of the abundance and activity of the relevant microorganisms in native peatlands. © 2013 Elsevier Ltd.
Castrillon E.E.,University of Aarhus
Journal of orofacial pain | Year: 2010
To determine if myofascial temporomandibular disorder (TMD) pain patients have elevated interstitial concentrations of glutamate in the masseter muscle. Thirteen patients (3 men, 10 women) diagnosed with myofascial TMD pain and 10 (2 men, 8 women) age-matched healthy controls participated in a single microdialysis session. Microdialysis was performed in the patients in the most painful point of the masseter muscle, while in the healthy subjects a standardized point in the muscle was chosen. Two microdialysis samples were collected over 40-minute epochs. A blood sample was also taken for analysis of plasma glutamate concentration. Numeric rating scale (NRS) scores of pain intensity and unpleasantness, McGill Pain Questionnaire data, pain drawing areas, pressure pain thresholds, pressure pain tolerances, maximum voluntary bite force, and maximum voluntary mouth opening were collected as secondary measurements. The median concentration of glutamate in the masseter muscle of the myofascial TMD pain patients (7.5 ± 2.6 ΜM) was significantly higher (P < .023, Mann-Whitney test) than the concentration in healthy controls (0.5 ± 0.4 ΜM). There were, however, no significant correlations between glutamate concentrations in the masseter muscle and NRS pain scores. Plasma concentrations of glutamate were similar in patients and healthy controls. The present study demonstrates a marked increase in interstitial glutamate concentration in the masseter muscle of myofascial TMD pain patients. These novel findings suggest that peripheral glutamate could be involved in the pathophysiology of myofascial TMD pain.
Ostenfeld-Rosenthal A.M.,University of Aarhus
Anthropology and Medicine | Year: 2012
The paper deals with a classical anthropological issue, the working mechanisms of rituals and the relation between healing rituals and the placebo effect. The point of departure of the paper is MUS (medically unexplained symptoms) patients' experiences of Danish healing rituals. The aim of the paper is to develop an understanding of how bodily experienced images of body and self work to transform the patient during a healing ritual. It is argued that a bodily founded symbolic re-editing of body- and self-image is an essential skill in healing rituals. In conclusion, it is argued that the placebo is nothing but the effectiveness of bodily experienced symbols. Copyright © 2012 Taylor & Francis.
Rattan S.I.S.,University of Aarhus
Current Pharmaceutical Design | Year: 2014
The science and study of the biological basis of aging, biogerontology, is now a well-established field with solid scientific base. A paradigm-shift in gerontology has occurred by realising the fact that biological aging occurs in spite of the presence of complex homeodynamic pathways of maintenance, repair and defence, and there is no "enemy within". This viewpoint separates the modulation of aging from the treatment of one or more age-related diseases. A promising strategy in biogerontology is to slow down aging and to extend healthspan by hormetin-mediated hormesis. Physical, nutritional and mental hormetins, which initiate stress responses and strengthen the homeodynamics, are potentially effective aging modulators. As a biomedical issue, the biological process of aging underlies all major diseases, and while the optimal treatment of every disease is a social and moral necessity, preventing the onset of agerelated diseases by intervening in the basic process of aging is the best approach for designing novel pharmaceutical interventions. © 2014 Bentham Science Publishers.
Larsen K.K.,University of Aarhus
Danish medical journal | Year: 2013
Myocardial infarction (MI) is a severe life event that is accompanied by an increased risk of depression. Mounting evidence suggests that post-MI depression is associated with adverse outcomes, but the underlying mechanisms of this association remain unclear, and no previous studies have examined whether the mental burden of MI is so heavy that it increases the risk of suicide. Although post-MI depression is common and burdensome, the condition remains under-recognised and under-treated. The development of new strategies to improve the quality of care for people with post-MI depression requires thorough understanding of the mechanisms that influence the prognosis as well as knowledge of the present care provided. The purpose of this PhD thesis is accordingly subdivided into four specific aims: 1. To estimate the prevalence of depression in people with MI after three months, and to estimate the provided hospital-based psychosocial rehabilitation (Paper I); 2. To examine GPs' practice of screening for depression in people with MI, and to analyse whether the screening rate varied among subgroups of people with a particularly high risk of post-MI depression (Paper II); 3. To examine the association between post-MI depression and new cardiovascular events or death, taking potential mediators into account (Paper III); 4. To examine the association between MI and suicide (Paper IV). Two different study designs were employed: a population-based cohort study using data obtained from registers and questionnaires sent to MI patients and their GPs (Paper I-III); a nationwide population-based matched case-control study using data obtained from registers (Paper IV). Three months after having suffered MI, about one fifth of the patients in our study had depression according to the Hospital Anxiety and Depression Scale (HADS). Upwards of half of the patients had participated in some rehabilitation, thirty per cent had participated in psychosocial support and three per cent reported that they had been examined for depression by questionnaire during the hospital-based rehabilitation. The rate of participation in psychosocial support and examination for depression was the same for patients with or without depression at three months following MI. A good fourth of the patients' GPs stated that they had screened the patient for depression within the first year after the patient suffered an MI. Three months after the MI, the screening rate was higher among patients with a history of mental illness and among patients with anxiety or depression than among patients without these conditions. Most of the GPs who performed screening followed guidelines by asking about specific depressive symptoms. According to the HADS, depression three months after MI was associated with an increased risk of a new cardiovascular event or death. This association was partly explained by the underlying cardiac disease severity and physical inactivity, but depression remained an independent prognostic risk factor after adjusting for these potential confounders. We found a tendency towards a weaker association with increasing physical activity and among users of antidepressants. MI was strongly associated with an increased risk of suicide. This risk was particularly high immediately after the MI, but remained high for more than five years after the MI. The association between MI and suicide remained stable throughout the study period (1981-2006), although many other factors changed (e.g. suicide rate, treatment of MI). This thesis demonstrated that post-MI depression is common, under-recognized and has a strong prognostic impact. About one in five patients have depression three months after MI. Guidelines recommend screening for depression, but the guidelines have not been systematically implemented either in the hospital-based rehabilitation or in Danish general practice. In the absence of systematic screening, we found that a significant part of those who had depression were not recognized. MI increases the risk of suicide, and depression following MI impairs the overall prognosis. The thesis indicates that physical activity and antidepressants modify the adverse prognosis in patients with post-MI depression, but larger studies are needed to clarify the impact of these potential modifiers and to evaluate how they may be catered for in the treatment of post-MI patients with depression.
Schneider J.W.,University of Aarhus
Scientometrics | Year: 2015
Null hypothesis statistical significance tests (NHST) are widely used in quantitative research in the empirical sciences including scientometrics. Nevertheless, since their introduction nearly a century ago significance tests have been controversial. Many researchers are not aware of the numerous criticisms raised against NHST. As practiced, NHST has been characterized as a ‘null ritual’ that is overused and too often misapplied and misinterpreted. NHST is in fact a patchwork of two fundamentally different classical statistical testing models, often blended with some wishful quasi-Bayesian interpretations. This is undoubtedly a major reason why NHST is very often misunderstood. But NHST also has intrinsic logical problems and the epistemic range of the information provided by such tests is much more limited than most researchers recognize. In this article we introduce to the scientometric community the theoretical origins of NHST, which is mostly absent from standard statistical textbooks, and we discuss some of the most prevalent problems relating to the practice of NHST and trace these problems back to the mix-up of the two different theoretical origins. Finally, we illustrate some of the misunderstandings with examples from the scientometric literature and bring forward some modest recommendations for a more sound practice in quantitative data analysis. © Akadémiai Kiadó, Budapest, Hungary 2014
Stukenbrock E.H.,University of Aarhus
PLoS genetics | Year: 2010
The fungus Mycosphaerella graminicola has been a pathogen of wheat since host domestication 10,000-12,000 years ago in the Fertile Crescent. The wheat-infecting lineage emerged from closely related Mycosphaerella pathogens infecting wild grasses. We use a comparative genomics approach to assess how the process of host specialization affected the genome structure of M. graminicola since divergence from the closest known progenitor species named M. graminicola S1. The genome of S1 was obtained by Illumina sequencing resulting in a 35 Mb draft genome sequence of 32X. Assembled contigs were aligned to the previously sequenced M. graminicola genome. The alignment covered >90% of the non-repetitive portion of the M. graminicola genome with an average divergence of 7%. The sequenced M. graminicola strain is known to harbor thirteen essential chromosomes plus eight dispensable chromosomes. We found evidence that structural rearrangements significantly affected the dispensable chromosomes while the essential chromosomes were syntenic. At the nucleotide level, the essential and dispensable chromosomes have evolved differently. The average synonymous substitution rate in dispensable chromosomes is considerably lower than in essential chromosomes, whereas the average non-synonymous substitution rate is three times higher. Differences in molecular evolution can be related to different transmission and recombination patterns, as well as to differences in effective population sizes of essential and dispensable chromosomes. In order to identify genes potentially involved in host specialization or speciation, we calculated ratios of synonymous and non-synonymous substitution rates in the >9,500 aligned protein coding genes. The genes are generally under strong purifying selection. We identified 43 candidate genes showing evidence of positive selection, one encoding a potential pathogen effector protein. We conclude that divergence of these pathogens was accompanied by structural rearrangements in the small dispensable chromosomes, while footprints of positive selection were present in only a small number of protein coding genes.
Jensen P.K.,University of Aarhus
Crop Protection | Year: 2012
Control of annual grass species with vertically oriented leaves in agricultural crops by application of foliar acting herbicides with conventional hydraulic sprayers can be increased using forward angled nozzles. Changing the spray angle from the normally predominantly vertical spray towards an angled spray increases the potential target size of vertically oriented targets. This theory was tested in field experiments from 2005 to 2009 investigating control of three different grass species and a dicotyledonous weed species at early growth stages using foliar acting herbicides. Lolium perenne and Alopecurus myosuroides are annual grasses with a predominantly vertical habit whereas Apera spica-venti and Brassica napus are species with more horizontally oriented leaves at growth stages where applications were carried out. Using a 60° forward angled spray resulted in large increases in herbicide efficacy on L. perenne at early growth stages using nozzles with different spray quality, at different driving speeds and in different wind conditions. Similarly graminicide efficacy was increased when nozzles were angled 60° forward controlling A. myosuroides. Experiments investigating control of the two species with a more horizontal habit, A. spica-venti and B. napus, gave no significant difference between results with standard and angled applications. © 2011 Elsevier Ltd.
Ollgaard B.,University of Aarhus
Phytotaxa | Year: 2012
This paper proposes new nomenclatural combinations for accepted Neotropical species, according to a new classification with nine Neotropical genera in three subfamilies of the Lycopodiaceae. New combinations for the species occurring in Brazil, are proposed elsewhere (Øllgaard, in press). There is one new combination in Palhinhaea, 119 in Phlegmariurus, and two in Pseudolycopodiella. © 2012 Magnolia Press.
Grinsted L.,University of Aarhus
Proceedings. Biological sciences / The Royal Society | Year: 2013
Deciphering the mechanisms involved in shaping social structure is key to a deeper understanding of the evolutionary processes leading to sociality. Individual specialization within groups can increase colony efficiency and consequently productivity. Here, we test the hypothesis that within-group variation in individual personalities (i.e. boldness and aggression) can shape task differentiation. The social spider Stegodyphus sarasinorum (Eresidae) showed task differentiation (significant unequal participation) in simulated prey capture events across 10-day behavioural assays in the field, independent of developmental stage (level of maturation), eliminating age polyethism. Participation in prey capture was positively associated with level of boldness but not with aggression. Body size positively correlated with being the first spider to emerge from the colony as a response to prey capture but not with being the first to attack, and dispersal distance from experimental colonies correlated with attacking but not with emerging. This suggests that different behavioural responses to prey capture result from a complex set of individual characteristics. Boldness and aggression correlated positively, but neither was associated with body size, developmental stage or dispersal distance. Hence, we show that personalities shape task differentiation in a social spider independent of age and maturation. Our results suggest that personality measures obtained in solitary, standardized laboratory settings can be reliable predictors of behaviour in a social context in the field. Given the wealth of organisms that show consistent individual behavioural differences, animal personality could play a role in social organization in a diversity of animals.
Kragh H.,University of Aarhus
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2012
Triatomic hydrogen became a major research area only after 1980, but its history goes back to J. J. Thomson's discovery in 1911. In fact, the possible existence of H3 was suggested as early as 1895. This paper outlines the history of H 3 and H 3 + up to the mid-1930s, when chemists and physicists ceased to believe in the existence of the H 3 molecule. In the intervening years, there was a great deal of interest in 'active hydrogen' and also in the configuration of H 3, which was examined by Bohr in 1919. While H 3 was abandoned, H 3 + was not. Although the properties of H 3 + were largely unknown, the existence of the ion was firmly established, and its structure studied by means of the new methods of quantum chemistry. © 2012 The Royal Society.
Damgaard C.,University of Aarhus
Ecology | Year: 2012
The use of state-space models for analyzing longitudinal hierarchical pin-point plant cover data is demonstrated. The main advantages of using a state-space model are (1) that the observed variance is separated into sampling variance and the more interesting structural variance which are needed for quantifying prediction uncertainty, (2) that missing values or an unbalanced sampling design readily may be accounted for, and (3) that the structural equation easily may be expanded and made as complex as necessary for modeling longitudinal pin-point cover data, thus allowing the incorporation of the most important ecological processes in the state-space model without technical difficulties. Typically, there is considerable spatial variation in plant abundance, and this variation is modeled using the Pölya-Eggenberger distribution (a generalization of the beta-binomial distribution). To illustrate this method, longitudinal hierarchical pin-point data of Erica tetralix in wet Danish heathlands were analyzed, including and excluding autocorrelation and an environmental covariable in the state-space model. The pin-point plant cover data showed a significant decrease in the plant cover of E. tetralix in the period from 2004 to 2009, with an annual decrease of about 10% in the logit-transformed cover. The distribution of predicted plant cover at a given site the following year was calculated, including and excluding the information of an environmental covariable. © 2012 by the Ecological Society of America.
O'Connor M.,University of Aarhus
Aging and Mental Health | Year: 2010
Complicated grief reactions are relatively common following spousal bereavement. Old-age spousal loss qualifies as a possible traumatic stressor; however, posttraumatic stress disorder (PTSD) as a possible complication of the loss has rarely been explored in this population. This study aimed to investigate the frequency of PTSD in elderly bereaved people across the first 18 months of bereavement. Additionally, risk factors for the prediction of bereavement outcome in relation to four domains of the bereavement process were investigated. Data were collected via self-report questionnaires measuring traumatic stress (Harvard Trauma Questionnaire (HTQ)), coping style (Coping Style Questionnaire (CSQ)), crisis support (Crisis Support Scale (CSS)), and personality (e.g., NEO-five factor inventory (NEO-FFI)). Elderly bereaved people (N = 296, Mean = 73 years) participated at 2, 6, 13, and 18 months post loss. The comparison group consisted of married elderly people who had experienced at least one significant loss (N = 276, mean = 70 years). The frequency of PTSD within the spousal bereaved group was high (16%) compared to the comparison group (4%) and remained stable across time. Each individual domain included in the current analysis was a predictor of PTSD 18 months post loss. Most predictors remained stable across time. A hierarchical regression analysis of the four domains predicted 49% of the variance, indicating a considerable overlap between the domains. Only one predictor, early posttraumatic distress, remained significant. The results confirm that loss of a spouse in old age is traumatic for some and that the effects of the loss remain over the first 18 months post loss. The results therefore underline the importance of further investigation into PTSD in the elderly bereaved. © 2010 Taylor & Francis.
Smith P.,University of Aberdeen |
Olesen J.E.,University of Aarhus
Journal of Agricultural Science | Year: 2010
There is a very significant, cost effective greenhouse gas (GHG) mitigation potential in agriculture. The annual mitigation potential in agriculture is estimated to be 4200, 2600 and 1600 Mt CO2 equiv/yr at C prices of 100, 50 and 20 US$/t CO2 equiv, respectively. The value of GHG mitigated each year is equivalent to 420 000, 130 000 and 32 000 million US$/yr for C prices of 100, 50 and 20 US$/t CO2 equiv, respectively. From both the mitigation and economic perspectives, we cannot afford to miss out on this mitigation potential. The challenge of agriculture within the climate change context is two-fold, both to reduce emissions and to adapt to a changing and more variable climate. The primary aim of the mitigation options is to reduce emissions of methane or nitrous oxide or to increase soil carbon storage. All the mitigation options, therefore, affect the carbon and/or nitrogen cycle of the agroecosystem in some way. This often not only affects the GHG emissions but also the soil properties and nutrient cycling. Adaptation to increased variability of temperature and rainfall involves increasing the resilience of the production systems. This may be done by improving soil water holding capacities through adding crop residues and manure to arable soils or by adding diversity to the crop rotations. Though some mitigation measures may have negative impacts on the adaptive capacity of farming systems, most categories of adaptation options for climate change have positive impacts on mitigation. These include: (1) measures that reduce soil erosion, (2) measures that reduce leaching of nitrogen and phosphorus, (3) measures for conserving soil moisture, (4) increasing the diversity of crop rotations by choices of species or varieties, (5) modification of microclimate to reduce temperature extremes and provide shelter, (6) land use change involving abandonment or extensification of existing agricultural land, or avoidance of the cultivation of new land. These adaptation measures will in general, if properly applied, reduce GHG emissions, by improving nitrogen use efficiencies and improving soil carbon storage. There appears to be a large potential for synergies between mitigation and adaptation within agriculture. This needs to be incorporated into economic analyses of the mitigation costs. The inter-linkages between mitigation and adaptation are, however, not very well explored and further studies are warranted to better quantify short- and long-term effects on suitability for mitigation and adaptation to climate change. In order to realize the full potential for agriculture in a climate change context, new agricultural production systems need to be developed that integrate bioenergy and food and feed production systems. This may possibly be obtained with perennial crops having low-environmental impacts, and deliver feedstocks for biorefineries for the production of biofuels, biomaterials and feed for livestock. Copyright © 2010 Cambridge University Press.
Ballantyne A.G.,University of Aarhus
Wiley Interdisciplinary Reviews: Climate Change | Year: 2016
The literature on climate change communication addresses a range of issues relevant to the communication of climate change and climate science to lay audiences or publics. In doing so, it approaches this particular challenge from a variety of different perspectives and theoretical frameworks. Analyzing the body of scholarly literature on climate change communication, this article critically reviews how communication is conceptualized in the literature and concludes that the field of climate change communication is characterized by diverging and incompatible understandings of communication as a theoretical construct. In some instances, communication theory appears reduced to an 'ad hoc' toolbox, from which theories are randomly picked to provide studies with a fitting framework. Inspired by the paradigm shift from transmission to interaction within communication theory, potential lessons from the field of communication theory are highlighted and discussed in the context of communicating climate change. Rooted in the interaction paradigm, the article proposes a meta-theoretical framework that conceptualizes communication as a constitutive process of producing and reproducing shared meanings. Rather than operating in separate ontological and epistemological perspectives, a meta-theoretical conceptualization of communication would ensure a common platform that advances multiperspective argumentation and discussion of the role of climate change communication in society. © 2016 Wiley Periodicals, Inc.
Schneider J.W.,University of Aarhus
Journal of Informetrics | Year: 2013
This article raises concerns about the advantages of using statistical significance tests in research assessments as has recently been suggested in the debate about proper normalization procedures for citation indicators by Opthof and Leydesdorff (2010). Statistical significance tests are highly controversial and numerous criticisms have been leveled against their use. Based on examples from articles by proponents of the use statistical significance tests in research assessments, we address some of the numerous problems with such tests. The issues specifically discussed are the ritual practice of such tests, their dichotomous application in decision making, the difference between statistical and substantive significance, the implausibility of most null hypotheses, the crucial assumption of randomness, as well as the utility of standard errors and confidence intervals for inferential purposes. We argue that applying statistical significance tests and mechanically adhering to their results are highly problematic and detrimental to critical thinking. We claim that the use of such tests do not provide any advantages in relation to deciding whether differences between citation indicators are important or not. On the contrary their use may be harmful. Like many other critics, we generally believe that statistical significance tests are over- and misused in the empirical sciences including scientometrics and we encourage a reform on these matters. © 2012 Elsevier Ltd.
Brandsborg B.,University of Aarhus
Danish medical journal | Year: 2012
It is well known that different surgical procedures like amputation, thoracotomy, inguinal herniotomy, and mastectomy are associated with a risk of developing chronic postsurgical pain. Hysterectomy is the most frequent gynecological procedure with an annual frequency of 5000 hysterectomies for a benign indication in Denmark, but is has not previously been documented in detail to what extent this procedure leads to chronic pain. The aim of this PhD thesis was therefore to describe the epidemiology, type of pain, risk factors, and predictive factors associated with chronic pain after hysterectomy for a benign indication. The thesis includes four papers, of which one is based on a questionnaire study, two are based on a prospective clinical study, and one is a review of chronic pain after hysterectomy. The questionnaire paper included 1135 women one year after hysterectomy. A postal questionnaire about pain before and after hysterectomy was combined with data from the Danish Hysterectomy Database. Chronic postoperative pain was described by 32%, and the identified risk factors were preoperative pelvic pain, previous cesarean section, other pain problems and pain as an indication for hysterectomy. Spinal anesthesia was associated with a decreased risk of having pain after one year. The type of surgery (i.e. abdominal or vaginal hysterectomy) did not influence chronic pain. The prospective paper included 90 women referred for a hysterectomy on benign indication. The tests were performed before, on day 1, and 4 months after surgery and included questionnaires about pain, coping, and quality of life together with quantitative sensory testing of pain thresholds. Seventeen percent had pain after 4 months, and the risk factors were preoperative pain problems elsewhere and a high intensity of acute postoperative pain. Type of surgery was not a risk factor. Preoperative brush-evoked allodynia, pinprick hyperalgesia, and vaginal pain threshold were associated with a high intensity of acute postoperative pain, and preoperative brush-evoked allodynia was also associated with pelvic pain after 4 months. This PhD thesis shows that chronic postoperative pain is present after hysterectomy in 17-32% of women. The identified main risk factors are described above. The findings indicate that it is not the nerve injury itself, but more likely the underlying individual susceptibility to pain that is important for the development of chronic pain after hysterectomy.
Jensen F.,University of Aarhus
Wiley Interdisciplinary Reviews: Computational Molecular Science | Year: 2013
Electronic structure methods for molecular systems rely heavily on using basis sets composed of Gaussian functions for representing the molecular orbitals. A number of hierarchical basis sets have been proposed over the last two decades, and they have enabled systematic approaches to assessing and controlling the errors due to incomplete basis sets. We outline some of the principles for constructing basis sets, and compare the compositions of eight families of basis sets that are available in several different qualities and for a reasonable number of elements in the periodic table. © 2012 John Wiley & Sons, Ltd.
Tolstikhin O.I.,Moscow Institute of Physics and Technology |
Madsen L.B.,University of Aarhus
Physical Review Letters | Year: 2013
We show that retardation in adjusting an electronic state to an instantaneous internuclear configuration caused by the finiteness of the electron's velocity breaks the validity of the Born-Oppenheimer (BO) approximation at large electron-nuclei distances. This applies even to the ground state. As a result, the BO approximation in the theory of tunneling ionization of molecules breaks down at sufficiently weak fields. We also show that to account for nuclear motion the weak-field asymptotic expansion for the tunneling ionization rate must be restructured. The predictions for the rate using the BO approximation and the asymptotic expansion are compared with numerical results for a one-dimensional three-body system modeling a diatomic molecule, with both electronic and nuclear motions treated exactly. © 2013 American Physical Society.
Mak T.N.,University of Aarhus
The Prostate | Year: 2013
Inflammation is commonly observed in radical prostatectomy specimens, and evidence suggests that inflammation may contribute to prostate carcinogenesis. Multiple microorganisms have been implicated in serving as a stimulus for prostatic inflammation. The pro-inflammatory anaerobe, Propionibacterium acnes, is ubiquitously found on human skin and is associated with the skin disease acne vulgaris. Recent studies have shown that P. acnes can be detected in prostatectomy specimens by bacterial culture or by culture-independent molecular techniques. Radical prostatectomy tissue samples were obtained from 30 prostate cancer patients and subject to both aerobic and anaerobic culture. Cultured species were identified by 16S rDNA gene sequencing. Propionibacterium acnes isolates were typed using multilocus sequence typing (MLST). Our study confirmed that P. acnes can be readily cultured from prostatectomy tissues (7 of 30 cases, 23%). In some cases, multiple isolates of P. acnes were cultured as well as other Propionibacterium species, such as P. granulosum and P. avidum. Overall, 9 of 30 cases (30%) were positive for Propionibacterium spp. MLST analyses identified eight different sequence types (STs) among prostate-derived P. acnes isolates. These STs belong to two clonal complexes, namely CC36 (type I-2) and CC53/60 (type II), or are CC53/60-related singletons. MLST typing results indicated that prostate-derived P. acnes isolates do not fall within the typical skin/acne STs, but rather are characteristic of STs associated with opportunistic infections and/or urethral flora. The MLST typing results argue against the likelihood that prostatectomy-derived P. acnes isolates represent contamination from skin flora. Copyright © 2012 Wiley Periodicals, Inc.
Damgaard C.,University of Aarhus |
Fayolle A.,CIRAD - Agricultural Research for Development
Journal of Ecology | Year: 2010
1. Currently, there is a debate among plant ecologists on the concepts of the intensity of competition and the importance of competition, which is central to many issues of modern plant population ecology and plant community ecology. 2. It is problematic that the current measures of intensity and importance of competition, typically, are reported as dimensionless indices because they hide the fact that both indices are functions of plant density and the level of the environmental gradient. 3. Here, a new formulation of the concepts is suggested, which explicitly highlights the functional dependencies on plant density and the level of the environmental gradient. The new measures are a generalization of the previous indices and correspond to the previous indices in the case of a simple experimental design. 4. The suggested measures of the intensity and importance of competition are exemplified using data from a response surface competition experiment between Agrostis capillaris and Festuca ovina along a herbicide gradient, where the expected clear effect of plant density was demonstrated. 5. Synthesis. As the suggested measures of the intensity and importance of competition explicitly highlight the functional dependencies on plant density and the level of the environmental gradient, we think that they will help to ensure a closer connection between experimental plant ecology and the attempts to model plant populations and communities. © 2009 British Ecological Society.
Nissen P.E.,University of Aarhus |
Schuster W.J.,National Autonomous University of Mexico
Astronomy and Astrophysics | Year: 2012
Context. A previous study of F and G main-sequence stars in the solar neighborhood has revealed the existence of two distinct halo populations with a clear separation in [α/Fe] for the metallicity range-1.4 < [Fe/H] <-0.7. Taking into account the kinematics and ages of the stars, some Galactic formation models suggest that the "high-alpha" halo stars were formed in situ, whereas the "low-alpha" stars have been accreted from satellite galaxies. Aims. In this paper we investigate if there is a systematic difference in the lithium abundances of stars belonging to the high-and low-alpha halo populations. Methods. Equivalent widths of the Li i 6707.8Å resonance line are measured from high resolution VLT/UVES and NOT/FIES spectra and used to derive Li abundances on the basis of MARCS model atmospheres. Furthermore, masses of the stars are determined from the log T eff-log g diagram by interpolating between evolutionary tracks based on Yonsei-Yale models. Results. There is no significant systematic difference in the lithium abundances of high-and low-alpha stars. For the large majority of stars with masses 0.7 < M/M · < 0.9 and heavy-element mass fractions 0.001 Z < 0.006, the lithium abundance is well fitted by a relation A(Li) = a 0 + a 1 M + a 2 Z + a 3 M Z, where a 0, a 1, a 2, and a 3 are constants. Extrapolating this relation to Z = 0 leads to a lithium abundance close to the primordial value predicted from standard Big Bang nucleosynthesis calculations and the WMAP baryon density. The relation, however, does not apply to stars with metallicities below [Fe/H]-1.5. Conclusions. We suggest that metal-rich halo stars were formed with a lithium abundance close to the primordial value, and that lithium in their atmospheres has been depleted in time with an approximately linear dependence on stellar mass and Z. The lack of a systematic difference in the Li abundances of high-and low-alpha stars indicates that an environmental effect is not important for the destruction of lithium. © 2012 ESO.
Green S.,University of Aarhus
Studies in History and Philosophy of Science Part C :Studies in History and Philosophy of Biological and Biomedical Sciences | Year: 2013
In recent years, the philosophical focus of the modeling literature has shifted from descriptions of general properties of models to an interest in different model functions. It has been argued that the diversity of models and their correspondingly different epistemic goals are important for developing intelligible scientific theories (Leonelli, 2007; Levins, 2006). However, more knowledge is needed on how a combination of different epistemic means can generate and stabilize new entities in science. This paper will draw on Rheinberger's practice-oriented account of knowledge production. The conceptual repertoire of Rheinberger's historical epistemology offers important insights for an analysis of the modelling practice. I illustrate this with a case study on network modeling in systems biology where engineering approaches are applied to the study of biological systems. I shall argue that the use of multiple representational means is an essential part of the dynamic of knowledge generation. It is because of-rather than in spite of-the diversity of constraints of different models that the interlocking use of different epistemic means creates a potential for knowledge production. © 2013 Elsevier Ltd.
Henriksen D.,University of Aarhus
Scientometrics | Year: 2016
This article examines the rise in co-authorship in the Social Sciences over a 34-year period. It investigates the development in co-authorship in different research fields and discusses how the methodological differences in these research fields together with changes in academia affect the tendency to co-author articles. The study is based on bibliographic data about 4.5 million peer review articles published in the period 1980–2013 and indexed in the 56 subject categories of the Web of Science’s Social Science Citation Index. The results show a rise in the average number of authors, share of co-authored and international co-authored articles in the majority of the subject categories. However, the results also show that there are great disciplinary differences to the extent of the rises in co-authorship. The subject categories with a great share of international co-authored articles have generally experienced an increase in co-authorship, but increasing international collaboration is not the only factor influencing the rise in co-authorship. Hence, the most substantial rises have occurred in subject categories, where the research often is based on the use of experiments, large data set, statistical methods and/or team-production models. © 2016, Akadémiai Kiadó, Budapest, Hungary.
Damgaard C.,University of Aarhus
Ecological Informatics | Year: 2013
Most plant species are spatially aggregated and here the importance of taking the spatial variation into account when analyzing plant cover data is demonstrated in a general stochastic model where both the within-site and the among-site spatial variation of species cover data are parameterized. Using a generalised binomial distribution (or Pólya-Eggenberger distribution), where the among-site variation in mean cover is modeled by a zero-inflated beta distribution, it is possible to adequately analyze hierarchical plant cover data and link the estimates to the underlying ecological processes. The model is demonstrated in a case-study of pin-point cover data of Erica tetralix from 1148 wet heathland plots at 84 Danish sites, and it is shown that both parameter estimates and the conclusions of hypotheses testing critically depend on the correct modeling of the observed spatial variation. Finally, statistical power simulations of plant cover measurements are presented, which will be useful for planning ecological experiments and monitoring programs. © 2013 Elsevier B.V.
Heller R.,McMaster University |
Albrecht S.,University of Aarhus
Astrophysical Journal Letters | Year: 2014
We present two methods to determine an exomoon's sense of orbital motion (SOM), one with respect to the planet's circumstellar orbit and one with respect to the planetary rotation. Our simulations show that the required measurements will be possible with the European Extremely Large Telescope (E-ELT). The first method relies on mutual planet-moon events during stellar transits. Eclipses with the moon passing behind (in front of) the planet will be late (early) with regard to the moon's mean orbital period due to the finite speed of light. This "transit timing dichotomy" (TTD) determines an exomoon's SOM with respect to the circumstellar motion. For the 10 largest moons in the solar system, TTDs range between 2 and 12 s. The E-ELT will enable such measurements for Earth-sized moons around nearby Sun-like stars. The second method measures distortions in the IR spectrum of the rotating giant planet when it is transited by its moon. This Rossiter-McLaughlin effect (RME) in the planetary spectrum reveals the angle between the planetary equator and the moon's circumplanetary orbital plane, and therefore unveils the moon's SOM with respect to the planet's rotation. A reasonably large moon transiting a directly imaged planet like β Pic b causes an RME amplitude of almost 100 m s-1, about twice the stellar RME amplitude of the transiting exoplanet HD209458 b. Both new methods can be used to probe the origin of exomoons, that is, whether they are regular or irregular in nature. © 2014. The American Astronomical Society. All rights reserved.
Miller M.R.,University of Birmingham |
Pedersen O.F.,University of Aarhus
European Respiratory Journal | Year: 2010
Spirometric lung function is partly determined by sex, age and height (Ht). Commonly, lung function is expressed as a percentage of the predicted value (PP) in order to account for these effects. Since the PP method retains sex, age and Ht bias, forced expiratory volume in 1 s (FEV1) standardised by powers of Ht and by a new sex-specific lower limit (FEV1 quotient (FEV1Q)) were investigated to determine which method best predicted all-cause mortality in >26,967 patients and normal subjects. On multivariate analysis, FEV1Q was the best predictor, with a hazard ratio for the worst decile of 6.9 compared to 4.1 for FEV1PP. On univariate analysis, the hazard ratios were 18.8 compared to 6.1, respectively; FEV1·Ht-3 was the next-best predictor of survival. Median survival was calculated for simple cut-off values of FEV1Q and FEV1·Ht-3. These survival curves were accurately fitted (r2=1.0) by both FEV1Q and FEV1·Ht-3 values expressed polynomially, and so an individual's test result could be used to estimate survival (with SD for median survival of 0.22 and 0.61 yrs, respectively). It is concluded that lung function impairment should be expressed in a new way, here termed the FEV1Q, or, alternatively, as FEV1·Ht -3, since these indices best relate spirometric lung function to all-cause mortality and survival. Copyright©ERS Journals Ltd 2010.
Corydon T.J.,University of Aarhus
Human Gene Therapy | Year: 2015
The idea of treating disease in humans with genetic material was conceived over two decades ago and with that a promising journey involving development and efficacy studies in cells and animals of a large number of novel therapeutic reagents unfolded. In the footsteps of this process, successful gene therapy treatment of genetic conditions in humans has shown clear signs of efficacy. Notably, significant advancements using gene supplementation and silencing strategies have been made in the field of ocular gene therapy, thereby pinpointing ocular gene therapy as one of the compelling "actors" bringing gene therapy to the clinic. Most of all, this success has been facilitated because of (1) the fact that the eye is an effortlessly accessible, exceedingly compartmentalized, and immune-privileged organ offering a unique advantage as a gene therapy target, and (2) significant progress toward efficient, sustained transduction of cells within the retina having been achieved using nonintegrating vectors based on recombinant adeno-associated virus and nonintegrating lentivirus vectors. The results from in vivo experiments and trials suggest that treatment of inherited retinal dystrophies, ocular angiogenesis, and inflammation with gene therapy can be both safe and effective. Here, the progress of ocular gene therapy is examined with special emphasis on the potential use of RNAi- and protein-based antiangiogenic gene therapy to treat exudative age-related macular degeneration. © 2015, Mary Ann Liebert, Inc.
Desbrosses G.J.,Montpellier University |
Stougaard J.,University of Aarhus
Cell Host and Microbe | Year: 2011
Legume plants have an exceptional capacity for association with microorganisms, ranging from largely nonspecific to very specific interactions. Legume-rhizobial symbiosis results in major developmental and metabolic changes for both the microorganism and host, while providing the plant with fixed nitrogen. A complex signal exchange leads to the selective rhizobial colonization of plant cells within nodules, new organs that develop on the roots of host plants. Although the nodulation mechanism is highly specific, it involves the same subset of plant phytohormones, namely auxin, cytokinin, and ethylene, which are required for root development. In addition, nodulation triggered by the rhizobia affects the development of the host root system, indicating that the microorganism can alter host developmental pathways. Nodulation by rhizobia is a prime example of how microorganisms and plants have coevolved and exemplifies how microbial colonization may affect plant developmental pathways. © 2011 Elsevier Inc.
Bykov D.,University of Aarhus |
Neese F.,Max Planck Institute For Chemische Energiekonversion
Inorganic Chemistry | Year: 2015
In this Forum Article, an extensive discussion of the mechanism of six-electron, seven-proton nitrite reduction by the cytochrome c nitrite reductase enzyme is presented. On the basis of previous studies, the entire mechanism is summarized and a unified picture of the most plausible sequence of elementary steps is presented. According to this scheme, the mechanism can be divided into five functional stages. The first phase of the reaction consists of substrate binding and N-O bond cleavage. Here His277 plays a crucial role as a proton donor. In this step, the N-O bond is cleaved heterolytically through double protonation of the substrate. The second phase of the mechanism consists of two proton-coupled electron-transfer events, leading to an HNO intermediate. The third phase involves the formation of hydroxylamine, where Arg114 provides the necessary proton for the reaction. The second N-O bond is cleaved in the fourth phase of the mechanism, again triggered by proton transfer from His277. The Tyr218 side chain governs the fifth and last phase of the mechanism. It consists of radical transfer and ammonia formation. Thus, this mechanism implies that all conserved active-site side chains work in a concerted way in order to achieve this complex chemical transformation from nitrite to ammonia. The Forum Article also provides a detailed discussion of the density functional theory based cluster model approach to bioinorganic reactivity. A variety of questions are considered: the resting state of enzyme and substrate binding modes, interaction with the metal site and with active-site side chains, electron- and proton-transfer events, substrate dissociation, etc. © 2015 American Chemical Society.
Kjaer J.B.,Friedrich Loeffler Institute |
Jorgensen H.,University of Aarhus
Genes, Brain and Behavior | Year: 2011
Domestic chicken lines of the White Leghorn type differing in their level of feather pecking were developed by divergent genetic selection specifically on feather pecking behavior. We determined parameters of heart rate variability to elucidate the relative activation of the sympathetic and parasympathetic nervous systems during rest and stressful situations. A total of 48 hens were tested in 8 batches. Segments of 2 min were extracted from electrocardiograms recorded by radio-transmitter implants, before (basal undisturbed conditions) and during physical restraint and a social test. Under basal conditions mean distance between R-waves were shorter in the low and high lines compared to the control. During physical restraint, stress reactions [reduced root of the mean squares of successive differences (RMSSD), reduced high frequency (HF), high low frequency (LF/HF) and low vagal-sympathetic effect (VSE) compared to basal levels] were significant in all lines. During the physical restraint the high feather pecking (HFP) line reacted significantly stronger than control (CON) and low feather pecking (LFP) line. During social test the LFP line reacted different than the other two lines. Seemingly birds from LFP conceived the social test as less stressful than birds from the CON and HFP lines. From this it follows that (1) physical restraint generally induced higher stress reactions than the social test and (2) genetic selection for higher levels of feather pecking increased the autonomic nervous system reaction to physical restraint whereas selection against feather pecking has reduced the response to increased social contact. © 2011 The Authors. Genes, Brain and Behavior © 2011 Blackwell Publishing Ltd and International Behavioural and Neural Genetics Society.
Offenberg J.,University of Aarhus
Journal of Applied Entomology | Year: 2011
Oecophylla ants are sold at high prices on several commercial markets as a human delicacy, as pet food or as traditional medicine. Currently markets are supplied by ants collected from the wild; however, an increasing interest in ant farming exists as all harvest is easily sold and as ant farming can be combined with the use of the ants in biological control programmes in tropical plantations where pest insects are converted into ant biomass. To assess the cost-benefits of ant farming based on artificial feeding, food consumption and food conversion efficiency (ECI) of Oecophylla smaragdina (Fabricius) was tested under laboratory conditions. Of the two types of food offered, the ants ingested 76% pure sucrose and 24% insect prey (dry weights) leading to ECI's of 29% and 39% including brood only or brood plus imago gain, respectively. Based on Thai sugar and protein food costs and ant brood selling prices these efficiencies led to rates of return from 1.52 to 4.56, respectively, if: (i) protein is supplied from commercial products; or (ii) alternatively supplied from free sources such as insects and kitchen waste. These results suggest that Oecophylla ant farming may become highly profitable and deserves further research. © 2010 Blackwell Verlag, GmbH.
Bijlsma R.,University of Groningen |
Loeschcke V.,University of Aarhus
Evolutionary Applications | Year: 2012
Biodiversity is increasingly subjected to human-induced changes of the environment. To persist, populations continually have to adapt to these often stressful changes including pollution and climate change. Genetic erosion in small populations, owing to fragmentation of natural habitats, is expected to obstruct such adaptive responses: (i) genetic drift will cause a decrease in the level of adaptive genetic variation, thereby limiting evolutionary responses; (ii) inbreeding and the concomitant inbreeding depression will reduce individual fitness and, consequently, the tolerance of populations to environmental stress. Importantly, inbreeding generally increases the sensitivity of a population to stress, thereby increasing the amount of inbreeding depression. As adaptation to stress is most often accompanied by increased mortality (cost of selection), the increase in the 'cost of inbreeding' under stress is expected to severely hamper evolutionary adaptive processes. Inbreeding thus plays a pivotal role in this process and is expected to limit the probability of genetically eroded populations to successfully adapt to stressful environmental conditions. Consequently, the dynamics of small fragmented populations may differ considerably from large nonfragmented populations. The resilience of fragmented populations to changing and deteriorating environments is expected to be greatly decreased. Alleviating inbreeding depression, therefore, is crucial to ensure population persistence. © 2011 Blackwell Publishing Ltd.
Christensen-Dalsgaard J.,University of Aarhus
Astronomische Nachrichten | Year: 2012
The recent asteroseismic data from the CoRoT and Kepler missions have provided an entirely new basis for investigating stellar properties. This has led to a rapid development in techniques for analysing such data, although it is probably fair to say that we are still far from having the tools required for the full use of the potential of the observations. Here I provide a brief overview of some of the issues related to the interpretation of asteroseismic data. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Damgaard C.,University of Aarhus
Journal of Ecology | Year: 2010
1. One of the possible mechanisms to maintain a high number of species in a plant community is that intraspecific aggregation due to limited dispersal reduces the importance of interspecific competition. 2. The hypothesis has been examined both theoretically and experimentally in the simplifying case of two species in a uniform abiotic environment, and there is a solid qualitative understanding that intraspecific aggregation reduces the importance of interspecific competition; however, there is considerable uncertainty as to the magnitude of this reduction in plant communities with many species in a heterogeneous environment and its effect on the number of coexisting species. 3. Here, the hypothesis was tested by comparing observed species richness at a site with a compound estimate of the intraspecific aggregation of all the species observed at the site, while taking the expected confounding effects of environmental spatial heterogeneity into account. 4. It is difficult to draw firm conclusions from the non-significant statistical results found in this study, as a lack of significance does not necessarily rule out the presence of an effect. However, based on the observation that species richness was not correlated with the degree of intraspecific aggregation, it was concluded that there was no additional support for the hypothesis that reduced interspecific competition due to intraspecific aggregation is important for maintaining the relatively species-rich flora in North-European dune grassland. 5. Synthesis. It is important to test whether it is possible to generalize the expected effects of intraspecific aggregation from manipulated experiments using only a few plant species to natural plant communities with many species, and the approach taken in this paper is a practically manageable approach. © 2010 The Author. Journal compilation © 2010 British Ecological Society.
Ho S.C.,University of Aarhus
Applied Soft Computing Journal | Year: 2015
This paper discusses the Single Source Capacitated Facility Location Problem (SSCFLP) where the problem consists in determining a subset of capacitated facilities to be opened in order to satisfy the customers' demands such that total costs are minimized. The paper presents an iterated tabu search heuristic to solve the SSCFLP. The iterated tabu search heuristic combines tabu search with perturbation operators to avoid getting stuck in local optima. Experimental results show that this simple heuristic is capable of generating high quality solutions using small computing times. Moreover, it is also competitive with other metaheuristic approaches for solving the SSCFLP. ©2014 Elsevier B.V. All rights reserved.
Kjaergaard M.,University of Aarhus
IEEE Pervasive Computing | Year: 2012
Building low-power location-based services that can run for hours on mobile phones is challenging. This survey of power conservation methods profiles how different phone features and types of LBSs consume power and discusses related design considerations. © 2006 IEEE.
Abu-Samha M.,University of Bergen |
Madsen L.B.,University of Aarhus
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011
We solve the three-dimensional time-dependent Schrödinger equation and present investigations of the imprint of the orbital angular node in photoelectron momentum distributions of an aligned atomic p-type orbital following ionization by an intense elliptically polarized laser pulse of femtosecond duration. We investigate the role of light ellipticity and the alignment angle of the major polarization axis of the external field relative to the probed orbital by studying radial and angular momentum distributions, the latter at a fixed narrow interval of final momenta close to the peak of the photoelectron momentum distribution. In general only the angular distributions carry a clear signature of the orbital symmetry. Our study shows that circular polarization gives the most clear imprints of orbital nodes. These findings are insensitive to pulse duration. © 2011 American Physical Society.
Lund H.,University of Aarhus
Journal of Solid State Electrochemistry | Year: 2011
The paper describes the change of the author's research from synthetic organic chemistry to electrochemistry and the advantages and disadvantages of having been trained in organic synthesis rather than in electrochemistry. The described research in electrochemistry includes, among other projects, oxidations in non-aqueous solvents, reduction of azomethine derivatives and heterocyclic compounds, synthesis of heterocyclic compounds, reduction of graphite, electrocatalytic reductions, electron transfer in nucleophilic substitutions and additions, determination of redox potentials of short-lived radicals, and electrochemical formation of Grignard compounds having reducible groups. At the end, some considerations after 60 years of research are included © 2011 Springer-Verlag.
Mayer P.,University of Aarhus
Integrated environmental assessment and management | Year: 2014
Passive sampling methods (PSMs) allow the quantification of the freely dissolved concentration (Cfree ) of an organic contaminant even in complex matrices such as sediments. Cfree is directly related to a contaminant's chemical activity, which drives spontaneous processes including diffusive uptake into benthic organisms and exchange with the overlying water column. Consequently, Cfree provides a more relevant dose metric than total sediment concentration. Recent developments in PSMs have significantly improved our ability to reliably measure even very low levels of Cfree . Application of PSMs in sediments is preferably conducted in the equilibrium regime, where freely dissolved concentrations in the sediment are well-linked to the measured concentration in the sampler via analyte-specific partition ratios. The equilibrium condition can then be assured by measuring a time series or a single time point using passive samplers with different surface to volume ratios. Sampling in the kinetic regime is also possible and generally involves the application of performance reference compounds for the calibration. Based on previous research on hydrophobic organic contaminants, it is concluded that Cfree allows a direct assessment of 1) contaminant exchange and equilibrium status between sediment and overlying water, 2) benthic bioaccumulation, and 3) potential toxicity to benthic organisms. Thus, the use of PSMs to measure Cfree provides an improved basis for the mechanistic understanding of fate and transport processes in sediments and has the potential to significantly improve risk assessment and management of contaminated sediments. © 2014 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC.
Holmstrup M.,University of Aarhus
Journal of Thermal Biology | Year: 2014
Many soil invertebrates have physiological characteristics in common with freshwater animals and represent an evolutionary transition from aquatic to terrestrial life forms. Their high cuticular permeability and ability to tolerate large modifications of internal osmolality are of particular importance for their cold tolerance. A number of cold region species that spend some or most of their life-time in soil are in more or less intimate contact with soil ice during overwintering. Unless such species have effective barriers against cuticular water-transport, they have only two options for survival: tolerate internal freezing or dehydrate. The risk of internal ice formation may be substantial due to inoculative freezing and many species rely on freeze-tolerance for overwintering. If freezing does not occur, the desiccating power of external ice will cause the animal to dehydrate until vapor pressure equilibrium between body fluids and external ice has been reached. This cold tolerance mechanism is termed cryoprotective dehydration (CPD) and requires that the animal must be able to tolerate substantial dehydration. Even though CPD is essentially a freeze-avoidance strategy the associated physiological traits are more or less the same as those found in freeze tolerant species. The most well-known are accumulation of compatible osmolytes and molecular chaperones reducing or protecting against the stress caused by cellular dehydration. Environmental moisture levels of the habitat are important for which type of cold tolerance is employed, not only in an evolutionary context, but also within a single population. Some species use CPD under relatively dry conditions, but freeze tolerance when soil moisture is high. © 2014 Elsevier Ltd.
Hoyvik I.-M.,Norwegian University of Science and Technology |
Jorgensen P.,University of Aarhus
Chemical Reviews | Year: 2016
The scope of this review article is to discuss the locality of occupied and virtual orthogonal Hartree-Fock orbitals generated by localization function optimization. Locality is discussed from the stand that an orbital is local if it is confined to a small region in space. Focusing on locality measures that reflects the spatial extent of the bulk of an orbital and the thickness of orbital tails, we discuss, with numerical illustrations, how the locality may be reported for individual orbitals as well as for sets of orbitals. Traditional and more recent orbital localization functions are reviewed, and the locality measures are used to compare the locality of the orbitals generated by the different localization functions, both for occupied and virtual orbitals. Numerical illustrations are given also for large molecular systems and for cases where diffuse functions are included in the atomic orbital basis. In addition, we have included a discussion on the physical and mathematical limitations on orbital locality. © 2016 American Chemical Society.
Zlatev Z.,University of Aarhus
Climatic Change | Year: 2010
The gradual increase in temperature is one of the most pronounced trends of climatic changes in the atmosphere. The pollution levels depend essentially on the emissions (both on the human-made emissions and on the biogenic emissions) as well as on the chemical reactions which take place during the transport of pollutants in the atmosphere. Since both the chemical reactions and the biogenic emissions depend on the temperature, it is obvious that the gradual increase of the temperature will have some effect on pollution levels. The impact of climatic changes on high ozone levels, which may have damaging effects on human health, is studied in this paper. Eight European suburban areas were selected. These areas are densely populated and, therefore, increased ozone pollution levels may cause harm to a great number of human beings living there. All experiments indicate that, although the changes of the ozone concentrations are relatively small, some critical levels, which are related to ozone concentrations and which may have damaging effects, will be significantly exceeded as a result of the warming trend in the future climate. © 2009 Springer Science+Business Media B.V.
Fago A.,University of Aarhus |
Jensen F.B.,University of Southern Denmark
Physiology | Year: 2015
Among vertebrates able to tolerate periods of oxygen deprivation, the painted and red-eared slider turtles (Chrysemys picta and Trachemys scripta) and the crucian carp (Carassius carassius) are the most extreme and can survive even months of total lack of oxygen during winter. The key to hypoxia survival resides in concerted physiological responses, including strong metabolic depression, protection against oxidative damage and–in air-breathing animals–redistribution of blood flow. Each of these responses is known to be tightly regulated by nitric oxide (NO) and during hypoxia by its metabolite nitrite. The aim of this review is to highlight recent work illustrating the widespread roles of NO and nitrite in the tolerance to extreme oxygen deprivation, in particular in the red-eared slider turtle and crucian carp, but also in diving marine mammals. The emerging picture underscores the importance of NO and nitrite signaling in the adaptive response to hypoxia in vertebrate animals. © 2015 by the American Physiological Society.
Tamiola K.,University of Groningen |
Mulder F.A.A.,University of Aarhus
Biochemical Society Transactions | Year: 2012
NMR spectroscopy offers the unique possibility to relate the structural propensities of disordered proteins and loop segments of folded peptides to biological function and aggregation behaviour. Backbone chemical shifts are ideally suited for this task, provided that appropriate reference data are available and idiosyncratic sensitivity of backbone chemical shifts to structural information is treated in a sensible manner. In the present paper, we describe methods to detect structural protein changes from chemical shifts, and present an online tool [ncSPC (neighbour-corrected Structural Propensity Calculator)], which unites aspects of several current approaches. Examples of structural propensity calculations are given for two well-characterized systems, namely the binding of α-synuclein to micelles and light activation of photoactive yellow protein. These examples spotlight the great power of NMR chemical shift analysis for the quantitative assessment of protein disorder at the atomic level, and further our understanding of biologically important problems. ©The Authors Journal compilation ©2012 Biochemical Society.
Abate G.D.,University of Aarhus
Spatial Economic Analysis | Year: 2016
This paper examines the link between macro volatility and economic growth in the lens of spatial econometrics. We present an unconstrained spatial Durbin Ramey-Ramey model. We test the extended model in a panel of 78 countries to investigate all the possible dimensions along which spatial interactions can affect the link between macro volatility and growth. In contrast to previous literature, we split the effects of volatility on growth into direct and indirect effects using partial derivative impacts approach. We found that both the direct and indirect effects of volatility on growth are negative; the latter effect suggesting the transmission of volatility shocks to neighbouring countries. Growth rates observed in neighbouring countries has a positive effect on growth rate of a particular country. © 2015 Regional Studies Association.
Qin P.,University of Aarhus
Journal of Psychiatric Research | Year: 2011
People with a psychiatric illness are at high risk for suicide; however, variation of the risk by patients' sex and age and by specific diagnosis needs to be explored in a more detail. This large population study systematically assesses suicide incidence rate ratio (IRR) and population attributable risk (PAR) associated with various psychiatric disorders by comparing 21,169 suicides in Denmark over a 17-year period with sex-age-time-matched population controls. The study shows that suicide risk is significantly increased for persons with a hospitalized psychiatric disorder and the associated risk varies significantly by diagnosis and by sex and age of subjects. Further adjustment for personal socioeconomic differences eliminates the IRRs associated with various disorders only to a limited extend. Recurrent depression and borderline personality disorder increase suicide risk the strongest while dementia increases the risk the least for both males and females. The influence of various disorders generally weakens with increasing age; however, there are important exceptions. Schizophrenia affects people aged ≤35 years the strongest in terms of both IRR and PAR. Recurrent depression increases suicide risk particularly strong in all age groups and the associated PAR increases steadily with age. Borderline personality disorder has a strong effect in young people, especially those ≤35 years. Alcohol use disorder accounts the highest PAR of suicides in males of 36-60 years old. For the elderly above 60 years old, reaction to stress and adjustment disorder increases the risk for suicide the most in both sexes. These findings suggest that approaches to psychiatric suicide prevention should be varied according to diagnosis and sex and age of subjects. © 2011 Elsevier Ltd.
Lan Z.,University of Southampton |
Bruun G.M.,University of Aarhus |
Lobo C.,University of Southampton
Physical Review Letters | Year: 2013
We show that atomic Fermi mixtures with density and mass imbalance exhibit a rich diversity of scaling laws for the quasiparticle decay rate beyond the quadratic energy and temperature dependence of conventional Fermi liquids. For certain densities and mass ratios, the decay rate is linear, whereas in other cases, it exhibits a plateau. Remarkably, this plateau extends from the deeply degenerate to the high temperature classical regime of the light species. Many of these scaling laws are analogous to what is found in very different systems, including dirty metals, liquid metals, and high temperature plasmas. The Fermi mixtures can in this sense span a whole range of seemingly diverse and separate physical systems. Our results are derived in the weakly interacting limit, making them quantitatively reliable. The different regimes can be detected with radio-frequency spectroscopy. © 2013 American Physical Society.
Lou H.C.,University of Aarhus
Acta Paediatrica, International Journal of Paediatrics | Year: 2012
Self-awareness is a pivotal component of any conscious experience and conscious self-regulation of behaviour. A paralimbic network is active, specific and causal in self-awareness. Its regions interact by gamma synchrony. Gamma synchrony develops throughout infancy, childhood and adolescence into adulthood and is regulated by dopamine and other neurotransmitters via GABA interneurons. Major derailments of this network and self-awareness occur in developmental disorders of conscious self-regulation like autism, attention deficit hyperactivity disorder (ADHD) and schizophrenia. Conclusion: Recent research on conscious experience is no longer limited to the study of neural 'correlations' but is increasingly lending itself to the study of causality. This paradigm shift opens new perspectives for understanding the neural mechanisms of the developing self and the causal effects of their disturbance in developmental disorders. © 2011 The Author(s)/Acta Pßdiatrica.
Orcutt B.N.,University of Aarhus |
Orcutt B.N.,University of Southern California |
Sylvan J.B.,University of Southern California |
Knab N.J.,University of Southern California |
Edwards K.J.,University of Southern California
Microbiology and Molecular Biology Reviews | Year: 2011
The majority of life on Earth - notably, microbial life - occurs in places that do not receive sunlight, with the habitats of the oceans being the largest of these reservoirs. Sunlight penetrates only a few tens to hundreds of meters into the ocean, resulting in large-scale microbial ecosystems that function in the dark. Our knowledge of microbial processes in the dark ocean - the aphotic pelagic ocean, sediments, oceanic crust, hydrothermal vents, etc. - has increased substantially in recent decades. Studies that try to decipher the activity of microorganisms in the dark ocean, where we cannot easily observe them, are yielding paradigm-shifting discoveries that are fundamentally changing our understanding of the role of the dark ocean in the global Earth system and its biogeochemical cycles. New generations of researchers and experimental tools have emerged, in the last decade in particular, owing to dedicated research programs to explore the dark ocean biosphere. This review focuses on our current understanding of microbiology in the dark ocean, outlining salient features of various habitats and discussing known and still unexplored types of microbial metabolism and their consequences in global biogeochemical cycling. We also focus on patterns of microbial diversity in the dark ocean and on processes and communities that are characteristic of the different habitats. Copyright © 2011, American Society for Microbiology. All Rights Reserved.
Jorgensen U.,University of Aarhus
Current Opinion in Environmental Sustainability | Year: 2011
The giant C4 grasses of the genus Miscanthus holds promise as candidates for the optimal bioenergy crop in the temperate zone with their high yield, cold tolerance, low environmental impact, resistance to pests and diseases, ease of harvesting and handling, and non-invasiveness. The latter is, however, only the case for the triploid and sterile species M.×giganteus, while great caution should be taken with the production of the seed-setting species of the genus. M. sinensis has already spread into nature from ornamental use in several parts of the world, where it is considered a serious invader. Other risks to consider are fire in the mature crop, the spread of pests and diseases and increased water use. These years, the first commercial large scale crop production results are coming through and will show if the promises are to be fulfilled and the risks can be handled. However, breeding, further development of the production chain, and stewardship programmes to avoid potential risks are still needed if Miscanthus is to compete with fossil fuel use and be widely produced. © 2010 Elsevier B.V.
Roepstorff A.,University of Aarhus
Behavioral and Brain Sciences | Year: 2013
Predictive processing models of cognition are promising an elegant way to unite action, perception, and learning. However, in the current formulations, they are species-unspecific and have very little particularly human about them. I propose to examine how, in this framework, humans can be able to massively interact and to build shared worlds that are both material and symbolic. © 2013 Cambridge University Press.
Kristensen M.D.,University of Aarhus
2010 IEEE International Conference on Pervasive Computing and Communications, PerCom 2010 | Year: 2010
Cyber foraging is a pervasive computing technique where small mobile devices offload resource intensive tasks to stronger computing machinery in the vicinity. This paper presents Scavenger - a new cyber foraging system supporting easy development of mobile cyber foraging applications, while still delivering efficient, mobile use of remote computing resources through the use of a custom built mobile code execution environment and a new dual-profiling scheduler. One of the main difficulties within cyber foraging is that it is very challenging for application programmers to develop cyber foraging enabled applications. An application using cyber foraging is working with mobile, distributed and, possibly, parallel computing; fields within computer science known to be hard for programmers to grasp. In this paper it is shown by example, how a highly distributed, parallel, cyber foraging enabled application can be developed using Scavenger. Benchmarks of the example application are presented showing that Scavenger imposes only minimal overhead when no surrogates are available, while greatly improving performance as surrogates become available. ©2009 IEEE.
Frith U.,University College London |
Frith U.,University of Aarhus
Quarterly Journal of Experimental Psychology | Year: 2012
In the 70 years since autism was described and named there have been huge changes in the conceptualization of this enigmatic condition. This review takes a personal perspective on the history of autism research. The origins of the first cognitive theories of autism, theory of mind and weak central coherence, are discussed and updated to inform future developments. Selected experimental findings are interpreted in the historical context of changes that have been brought about by advances in methodology. A three-level framework graphically illustrates a causal chain between brain, mind, and behaviour to facilitate the identification of phenotypes in neurodevelopmental disorders. Cognition is placed at the centre of the diagram to reveal that it can link together brain and behaviour, when there are complex multiple mappings between the different levels. © 2012 Copyright The Experimental Psychology Society.
Kaack K.,University of Aarhus
Horticultural Science | Year: 2014
Chemical compounds identification that cause the mouldy, musty and earthy off-odours of apple fruit stored in controlled atmosphere at low temperature for several months has been studied. Compounds with off-odour were extracted from cv. Golden Delicious apple peel using ether and purified on a silica-aluminium column with washing using a sodium carbonate solution. Presence of compounds with mouldy, musty and earthy off-odour in extracts and washings was verified using a sensory panel with four members intensively trained in identification and description of the odour throughout the whole analytical process. Separation of compounds in the final extract by gas chromatography showed that the odour was associated with five peaks associated with oxidation products of α-farnesene.
Merrison J.P.,University of Aarhus
Aeolian Research | Year: 2012
The transport of granular materials by wind has a major impact on our environment through sand/soil erosion and the generation and transport of atmospheric dust aerosols. Terrestrially the transport of dust involves billions of tons of material every year, influencing the global climate and impacting directly upon human health. Research in aeolian transport involves the inter-related fields of fluid dynamics, granular materials and electrification/electrostatics which are in themselves diverse and complex. This review only touches upon this intricacy, but aims to overview the latest work which is expanding our current understanding and outline the areas of advancement needed in the future. Presentation is made of current models for wind driven detachment/entrainment and the transport rates of sand and dust, including the effects of contact induced grain electrification. This ubiquitous phenomenon can affect grain transport through the generation of intense electric fields and processes of electrostatic assembly. Importantly the transport of sand is characterized by saltation, which is known to be an active process for erosion and therefore a source for dust and sand formation. Using novel erosion simulation techniques the link between grain transport rates and erosion rates has been quantified. Furthermore this can be linked to production rates for dust and has been associated with chemical and mineral alteration through a process of mechanical activation of fractured surfaces. This work has implications for the evolution of all terrestrial-like planetary surfaces. Studies in non-terrestrial environments force researchers to be less empirical, ultimately leading to a deeper understanding of these processes. © 2011 Elsevier B.V..
Jakobsen M.U.,University of Aarhus
Current Opinion in Lipidology | Year: 2011
Purpose of review: Intake of saturated fatty acids (SFAs) increases the low-density lipoprotein cholesterol concentration in plasma and has therefore been suggested to increase the risk of ischemic heart disease (IHD). Focus on limiting SFA intake without specifying the substitutions may be counterproductive because SFAs may be replaced with other equally or more harmful macronutrients. Recent findings on substitution of specified macronutrients for SFAs and risk of IHD are reviewed. Recent findings: Recent cohort studies suggest that intake of polyunsaturated fatty acids (PUFAs) or carbohydrates with low-glycemic index values in place of SFAs is associated with a lower risk of IHD whereas intake of carbohydrates with high-glycemic index values in place of SFAs is associated with a higher risk of IHD. Summary: Cohort studies and randomized clinical trials provide convincing evidence of a lower risk of IHD associated with substitution of PUFAs for SFAs. Analyzing substitution of specified macronutrients for SFAs offers a perspective different from the single nutrient focus and may provide further insight into IHD prevention. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Rattan S.I.S.,University of Aarhus
Aging and Disease | Year: 2014
Aging of biological systems occurs in spite of numerous complex pathways of maintenance, repair and defense. There are no gerontogenes which have the specific evolutionary function to cause aging. Although aging is the common cause of all age-related diseases, aging in itself cannot be considered a disease. This understanding of aging as a process should transform our approach towards interventions from developing illusory anti-aging treatments to developing realistic and practical methods for maintaining health throughout the lifespan. The concept of homeodynamic space can be a useful one in order to identify a set of measurable, evidence-based and demonstratable parameters of health, robustness and resilience. Age-induced health problems, for which there are no other clear-cut causative agents, may be better tackled by focusing on health mechanisms and their maintenance, rather than only disease management and treatment. Continuing the disease-oriented research and treatment approaches, as opposed to health-oriented and preventive strategies, are economically, socially and psychologically unsustainable.
Staugaard S.R.,University of Aarhus
Clinical Psychology Review | Year: 2010
A threatening facial expression is a potent social sign of hostility or dominance. During the past 20. years, photographs of threatening faces have been increasingly included as stimuli in studies with socially anxious participants, based on the hypothesis that a threatening face is especially salient to people with fears of social interaction or negative evaluation. The purpose of this literature review is to systematically evaluate the accumulated research and suggest possible avenues for further research. The main conclusion is that photographs of threatening faces engage a broad range of perceptual processes in socially anxious participants, particularly when exposure times are very short. © 2010 Elsevier Ltd.
Gonzalez S.F.,Harvard University |
Degn S.E.,University of Aarhus |
Pitcher L.A.,Harvard University |
Woodruff M.,Harvard University |
And 2 more authors.
Annual Review of Immunology | Year: 2011
The clonal selection theory first proposed by Macfarlane Burnet is a cornerstone of immunology (1). At the time, it revolutionized the thinking of immunologists because it provided a simple explanation for lymphocyte specificity, immunological memory, and elimination of self-reactive clones (2). The experimental demonstration by Nossal & Lederberg (3) that B lymphocytes bear receptors for a single antigen raised the central question of where B lymphocytes encounter antigen. This question has remained mostly unanswered until recently. Advances in techniques such as multiphoton intravital microscopy (4, 5) have provided new insights into the trafficking of B cells and their antigen. In this review, we summarize these advances in the context of our current view of B cell circulation and activation. © 2011 by Annual Reviews. All rights reserved.
Jensen B.E.,University of Aarhus
Nanoscale | Year: 2013
Drug-eluting engineered surface coatings are of paramount importance for many biomedical applications from implantable devices to tissue engineering. Herein, we present the assembly of lipogels, composite physical hydrogels assembled from poly(vinyl alcohol) and liposomes using thiol-disulfide exchange between end group modified PVA and thiocholesterol containing liposomes, and the response of adhering cells to these coatings. We demonstrate the controlled loading of liposomes into the polymer matrix and the preserved mechanical properties of the lipogels. Furthermore, the lipogels are successfully rendered cell adhesive by incorporation of poly(l-lysine) into the PVA polymer matrix or by poly(dopamine) coating of the lipogels. The successful lipid uptake from the lipogels by macrophages, hepatocytes, and myoblasts was monitored by flow cytometry. Finally, the delivery of active cargo, paclitaxel, to adherent myoblasts is shown, thus illustrating the potential of the lipogels as a drug eluting interface for biomedical applications.
Andresen K.J.,University of Aarhus
Marine Geology | Year: 2012
Fluid flow features such as sandstone intrusions, mud volcano systems and pockmarks represent well-known geological structures generated due to flow of fluids in the subsurface. However, the integration of fluid flow features in quantitative and qualitative basin analysis is still in its infancy. This study presents a review and a qualitative integration of fluid flow features in basin analysis of the Danish North Sea area and of salt mini-basins offshore Angola, based on results from six case studies focusing on the detection, mapping and evaluation of features related to focused fluid flow in these areas. In the study the diversity of seismically imaged fluid flow features in hydrocarbon plumbing systems is reviewed and their utility is demonstrated. This is done by focusing on the aspects of fluid flow related features that can be integrated into basin analysis studies and how these may help us increase the understanding of basin evolution and to achieve the major goals of basin analysis such as understanding the depositional and tectonic context of the basin and the presence and extent of hydrocarbons. Particularly concerning the determination of fluid flow timing, triggers, sources, and routes, fluid flow features represent a major but underused tool in basin analysis. © 2012 Elsevier B.V.
Riede F.,University of Aarhus
Quaternary International | Year: 2016
Around 13,000 years ago, the Laacher See volcano (East Eifel volcanic field, Rhenish Shield) erupted cataclysmically. The thick tephra blanket in the eruption's near field covered and thereby preserved a large number of archaeological sites, ranging from very small to some of the largest and richest sites known from the Late Glacial. In this proximal region, there is a striking contrast in the number of sites prior to the eruption and the almost complete lack of sites dating to the period after the event, i.e. to Greenland Interstadial 1a. The preservative function of the tephra cover itself may explain this near-field pattern, but it is shown here that similar stratigraphic observations can also be made in the Laacher See eruption's mid field towards the west and, in particular, to the north-east. The aim of this paper is to review the stratigraphic relations of known archaeological sites outside the near field of the Laacher See event with a particular focus on the German Federal State of Hesse and adjacent areas of Lower Saxony and the Thuringian Basin. Here, a number of archaeological sites are known, where strata of Laacher See tephra cap human occupation. Most often, these sites are not reoccupied until much later in prehistory, suggesting that the eruption may have led either to a complete or a near-complete abandonment of the affected regions or, at the very least, to a major reorganisation of landscape-use. © 2014 Elsevier Ltd and INQUA.
O'Connor M.,University of Aarhus
Aging and Mental Health | Year: 2010
Late life bereavement has been associated with psychological problems, mainly depression. A few studies indicated that posttraumatic stress disorder (PTSD) was an important issue in late life bereavement reactions. This study aimed to assess the prevalence of PTSD in recently bereaved older people compared with married controls and to investigate whether the loss of a spouse in old age, in contrast with earlier assumptions, could lead to PTSD. Two hundred and ninety-six Danish older bereaved people (mean age 73 years, 113 males) were chosen from national registers and assessed two months postbereavement. They were compared with a control group of 276 married older people. The prevalence of PTSD and depression were measured through a self-report questionnaire. Results showed that 16% of the bereaved and 4% of the control group had a PTSD diagnosis (ES = 0.35; Cohen's d = 0.74). Additionally, 37% of the bereaved and 22% of the control group had mild to severe depression (ES = 0.19; Cohen's d = 0.37). The results suggested that late life spousal bereavement result in PTSD with equal frequency to general samples of bereaved persons. Furthermore, the prevalence of PTSD in the first months after bereavement was more elevated than the level of depression. This makes PTSD an important factor when studying late life bereavement reactions. © 2010 Taylor & Francis.
Larsen K.G.,University of Aarhus
Proceedings of the Annual ACM Symposium on Theory of Computing | Year: 2012
In this paper we develop a new technique for proving lower bounds on the update time and query time of dynamic data structures in the cell probe model. With this technique, we prove the highest lower bound to date for any explicit problem, namely a lower bound of t q=Ω((lg n/lg(wt u)) 2). Here n is the number of update operations, w the cell size, t q the query time and t u the update time. In the most natural setting of cell size w=Θ(lg n), this gives a lower bound of t q=Ω((lg n/lg lg n) 2) for any polylogarithmic update time. This bound is almost a quadratic improvement over the highest previous lower bound of Ω(lg n), due to Patrascu and Demaine [SICOMP'06]. We prove our lower bound for the fundamental problem of weighted orthogonal range counting. In this problem, we are to support insertions of two-dimensional points, each assigned a Θ(lg n)-bit integer weight. A query to this problem is specified by a point q=(x,y), and the goal is to report the sum of the weights assigned to the points dominated by q, where a point (x′,y′) is dominated by q if x′ ≤ x and y′ ≤ y. In addition to being the highest cell probe lower bound to date, our lower bound is also tight for data structures with update time t u = Ω(lg 2+εn), where ε>0 is an arbitrarily small constant. © 2012 ACM.
Schilhab T.,University of Aarhus
Progress in Biophysics and Molecular Biology | Year: 2015
Contemporary neuroscience studies propose that sensory-motor experiences in the form of 're-enactments' or 'simulations' are significant to the individual's development of concepts and language use. To a certain extent, such studies align with non-Cartesian perspectives on situated cognition. Since perceptual activity is reflected neurally, however, the neural perspective of experiences and re-enactments allows us to distinguish between online and offline conditions within situated cognition, thereby addressing the extent to which direct experiences contribute to a particular learning episode. Whereas online situated cognition reflects the 'traditional' 4e's (minds as embodied, embedded, enacted, and extended) and focus is on cognitive processes confined to the individual, offline situated cognition introduces Others as significant contributors to cognitive processes in the individual.In this paper, I analyse how offline situated cognition entails a hitherto underdescribed but radical receptivity to the social world that works through language. Based on the unfolding of how we acquire the concepts of mental states as part of theory of mind, I establish that in the hands of interlocutors, words cultivate minds by first eliciting phenomenal sensations and then facilitating an association of these to experiences that originate with a different phenomenal content. Thus, I conclude both that phenomenal experiences online are central to conceptual learning offline through re-enactions and that Others are profoundly essential in forming cognising Selves. © 2015 .
Kolind T.,University of Aarhus
International Journal of Drug Policy | Year: 2015
Background: Drugs play an increasing role in contemporary prison life. Prisoners' drug use, drug smuggling and drug selling have also had a growing impact on the work routines and practices of prison officers. This has led to critiques that prison staff have become 'too lenient' regarding drug use. Methods: Based on observational data, qualitative interviews and survey data, this study examines the role of drugs in the way Danish prison officers exercise power. Results: Two forms of power are analysed: institutional power, by which the officers can sanction or reward inmates in everyday prison life, and personal power, by which the officers' personal authority and skills can reduce the more intrusive aspects of prison control. These forms of power are applied by officers' use of discretion in order to maintain what they consider to be adequate levels of peace and order in the prison wings. It is shown that officers are highly ambivalent towards the presence of drugs in prisons. On the one hand, they support the stricter drug policies implemented over the past two decades. On the other hand, they are aware that drug use can have a positive function in the everyday running of the prison. Officers' acceptance of inmates' drug use (mainly cannabis), therefore, is not necessarily a sign of leniency but one way in which prison officers exercise their power in prison settings. Conclusions: It is concluded that discretionary power is still very central to the officers' work. This conclusion contradicts recent arguments that prison officers' agency is being threatened or restricted by 'neoliberal' management reforms. The prison officers' discretion and informal power is the key to understanding their acceptance of inmates' drug use. © 2015 Elsevier B.V..
Aalkjaer C.,University of Aarhus
Acta physiologica (Oxford, England) | Year: 2011
This minireview discusses vasomotion, which is the oscillation in tone of blood vessels leading to flowmotion. We will briefly discuss the prevalence of vasomotion and its potential physiological and pathophysiological relevance. We will also discuss the models that have been suggested to explain how a coordinated oscillatory activity of the smooth muscle tone can occur and emphasize the role of the endothelium, the handling of intracellular Ca(2+) and the role of smooth muscle cell ion conductances. It is concluded that vasomotion is likely to enhance tissue dialysis, although this concept still requires more experimental verification, and that an understanding at the molecular level for the pathways leading to vasomotion is beginning to emerge. © 2011 The Authors. Acta Physiologica © 2011 Scandinavian Physiological Society.
Rosendal M.,University of Aarhus
The Cochrane database of systematic reviews | Year: 2013
Patients with medically unexplained or functional somatic symptoms are common in primary care. Previous reviews have reported benefit from specialised interventions such as cognitive behavioural therapy and consultation letters, but there is a need for treatment models which can studies including all of the following: 1) a trial arm with treatment as usual; 2) an intervention using a structured treatment model which draws on explanations for symptoms in broad bio-psycho-social terms or encourages patients to develop additional strategies for dealing with their physical symptoms, or both; 3) delivery of the intervention by primary care professionals providing first contact care; and 4) assessment of patient outcome. Two authors independently screened identified study abstracts. Disagreements about trial selections were resolved by a third review author. Data from selected publications were independently extracted and risk of bias assessed by two of three authors, avoiding investigators reviewing their own studies. We contacted authors from included studies to obtain missing information. We used continuous outcomes converted to standardised mean differences (SMDs) and based analyses on changes from baseline to follow-up, adjusted for clustering. We included seven studies from the literature search, but only six provided sufficient data for analyses. Included studies were European, cluster RCTs with adult participants seeing their usual doctor (in total 233 general practitioners and 1787 participants). Methodological quality was only moderate as studies had no blinding of healthcare professionals and several studies had a risk of recruitment and attrition bias. Studies were heterogeneous with regard to selection of patient populations and intensity of interventions. Outcomes relating to physical or general health (physical symptoms, quality of life) showed substantial heterogeneity between studies (I(2) > 70%) and post hoc analysis suggested that benefit was confined to more intensive interventions; thus we did not calculate a pooled effect. Outcomes relating to mental health showed less heterogeneity and we conducted meta-analyses, which found non-significant overall effect sizes with SMDs for changes at 6 to 24 months follow-up: mental health (3 studies) SMD -0.04 (95% CI -0.18 to 0.10), illness worry (3 studies) SMD 0.09 (95% CI -0.04 to 0.22), depression (4 studies) SMD 0.07 (95% CI -0.05 to 0.20) and anxiety (2 studies) SMD -0.07 (95% CI -0.38 to 0.25). Effects on sick leave could not be estimated. Three studies of patient satisfaction with care all showed positive but non-significant effects, and measures were too heterogeneous to allow meta-analysis. Results on healthcare utilisation were inconclusive. We analysed study discontinuation and found that both short term and long term discontinuation occurred more often in patients allocated to the intervention group, RR of 1.25 (95% CI 1.08 to 1.46) at 12 to 24 months. Current evidence does not answer the question whether enhanced care delivered by front line primary care professionals has an effect or not on the outcome of patients with functional somatic symptoms. Enhanced care may have an effect when delivered per protocol to well-defined groups of patients with functional disorders, but this needs further investigation. Attention should be paid to difficulties including limited consultation time, lack of skills, the need for a degree of diagnostic openness, and patient resistance towards psychosomatic attributions. There is some indication from this and other reviews that more intensive interventions are more successful in changing patient outcomes.
Martin-Nielsen J.,University of Aarhus
Wiley Interdisciplinary Reviews: Climate Change | Year: 2015
Today, numerical modelling is widely seen as the leading method of climate research. Modelling enjoys a hegemonic status in the production of climate predictions and the discussion and policy application of climate knowledge. This dominance obscures past and present debates about which types of climate knowledge are important, which epistemic standards are used to judge that knowledge, and which applications of that knowledge are considered useful. In the existing historiography of climate research, the focus has overwhelmingly been on numerical modelling, and relatively little has been written about other ways of knowing climate. The hegemony that numerical models enjoy today is not the result of a linear 'arrow of progress,' beginning with the introduction of digital computers and leading naturally to today's situation, but rather of a more complex situation centered on changing ideas of climate, the identity of climate researchers, and the direction and scope of their work. This paper aims to shed light on these ideas by investigating and analyzing climate research debates in the 1960s and early 1970s through the lens of the English meteorologist and climatologist Hubert Horace Lamb (1913-1997). It pays particular attention to Lamb's understanding of climatology as a discipline and his assessment of that discipline through the latter half of the 20th century. © 2015 Wiley Periodicals, Inc.
Brugger N.,University of Aarhus
Social Science Computer Review | Year: 2013
This article discusses some of the fundamental methodological challenges related to doing historical network analyses of the web based on material in web archives. Since the late 1990s many countries have established extensive national web archives, and software supported network analysis of the online web has for a number of years gained currency within Internet studies. However, the combination of these two phenomena-historical network analysis of material in web archives-can at best be characterized as an emerging new area of study. Most of the methodological challenges within this new area revolve around the specific nature of archived web material. On the basis of an introduction to the processes involved in web archiving as well as of the characteristics of archived web material, the article outlines and scrutinizes some of the major challenges which may arise when doing network analysis in web archives, among others such issues as completeness, construction of a corpus, temporal and spatial inconsistencies, and cross-archive analyses. The article uses an ongoing case study to feed the methodological discussion, namely the political network on the web which was available to a voter at the Danish parliamentary elections in 2011, 2007, and 2001. As the Internet grows older historical studies of networks on the web will probably become more widespread and therefore it may be about time to begin debating the methodological challenges within this emerging field. © The Author(s) 2012.
Fadista J.,Lund University |
Bendixen C.,University of Aarhus
PLoS ONE | Year: 2012
The field of genetics has come to rely heavily on commercial genotyping arrays and accompanying annotations for insights into genotype-phenotype associations. However, in order to avoid errors and false leads, it is imperative that the annotation of SNP chromosomal positions is accurate and unambiguous. We report on genomic positional discrepancies of various SNP chips for human, cattle and mouse species, and discuss their causes and consequences. © 2012 Fadista, Bendixen.
Angelova A.,University Paris - Sud |
Angelov B.,University of Aarhus |
Angelov B.,Czech Institute of Macromolecular Chemical |
Angelov B.,Bulgarian Academy of Science |
And 3 more authors.
Accounts of Chemical Research | Year: 2011
Lipids and lipopolymers self-assembled into biocompatible nano- and mesostructured functional materials offer many potential applications in medicine and diagnostics. In this Account, we demonstrate how high-resolution structural investigations of bicontinuous cubic templates made from lyotropic thermosensitive liquid-crystalline (LC) materials have initiated the development of innovative lipidopolymeric self-assembled nanocarriers. Such structures have tunable nanochannel sizes, morphologies, and hierarchical inner organizations and provide potential vehicles for the predictable loading and release of therapeutic proteins, peptides, or nucleic acids. This Account shows that structural studies of swelling of bicontinuous cubic lipid/water phases are essential for overcoming the nanoscale constraints for encapsulation of large therapeutic molecules in multicompartment lipid carriers.For the systems described here, we have employed time-resolved small-angle X-ray scattering (SAXS) and high-resolution freeze-fracture electronic microscopy (FF-EM) to study the morphology and the dynamic topological transitions of these nanostructured multicomponent amphiphilic assemblies. Quasi-elastic light scattering and circular dichroism spectroscopy can provide additional information at the nanoscale about the behavior of lipid/protein self-assemblies under conditions that approximate physiological hydration.We wanted to generalize these findings to control the stability and the hydration of the water nanochannels in liquid-crystalline lipid nanovehicles and confine therapeutic biomolecules within these structures. Therefore we analyzed the influence of amphiphilic and soluble additives (e.g. poly(ethylene glycol)monooleate (MO-PEG), octyl glucoside (OG), proteins) on the nanochannels size in a diamond (D)-type bicontinuous cubic phase of the lipid glycerol monooleate (MO). At body temperature, we can stabilize long-living swollen states, corresponding to a diamond cubic phase with large water channels. Time-resolved X-ray diffraction (XRD) scans allowed us to detect metastable intermediate and coexisting structures and monitor the temperature-induced phase sequences of mixed systems containing glycerol monooleate, a soluble protein macromolecule, and an interfacial curvature modulating agent. These observed states correspond to the stages of the growth of the nanofluidic channel network.With the application of a thermal stimulus, the system becomes progressively more ordered into a double-diamond cubic lattice formed by a bicontinuous lipid membrane. High-resolution freeze-fracture electronic microscopy indicates that nanodomains are induced by the inclusion of proteins into nanopockets of the supramolecular cubosomic assemblies. These results contribute to the understanding of the structure and dynamics of functionalized self-assembled lipid nanosystems during stimuli-triggered LC phase transformations. © 2010 American Chemical Society.
Kizach J.,University of Aarhus
Memory and Cognition | Year: 2013
In this study, we investigated the interaction between givenness and complexity on the choice of syntactic structure, via two experiments using speeded acceptability judgments. Experiment 1 showed that for the Danish dative alternation, given-new orders are only easier to process for double-object or NP constructions, whereas PP constructions are unaffected. This replicates previous findings for the English dative alternation. Experiment 2 revealed that when a long NP precedes a short NP-a suboptimal complexity relation-the effect of givenness is neutralized, whereas givenness remains influential when the complexity relation between the NPs in the sentence is optimal. This is consistent with the view that in online parsing, the actual syntactic structure-building process is primary, whereas any higher-order computations such as discourse linking are secondary. The relative complexity of the NPs in the double-object construction directly affects the structure-building process, whereas the decoding of the discourse structure is a later and less crucial phenomenon, resulting in neutralization of the givenness effect in cases in which the complexity relation is suboptimal. © 2013 Psychonomic Society, Inc.
Magura T.,Hortobagy National Park Directorate |
Lovei G.L.,University of Aarhus |
Tothmeresz B.,Debrecen University
Global Ecology and Biogeography | Year: 2010
Aim: We wanted to test whether urbanization has similar effects on biodiversity in different locations, comparing the responses of ground beetle (Coleoptera, Carabidae) assemblages with an urbanization gradient. We also wanted to see if urbanization had a homogenizing effect on ground beetle assemblages. Locations: Nine forested temperate locations in Europe, Canada and Japan. Methods: Published results of the Globenet Project were used. At all locations, three stages were identified: (1) a forested (rural) area, (2) a suburban area where the original forest was fragmented and isolated, and (3) remnants of the original forest in urban parks. These habitats formed an urbanization series. Study arrangements (number and operation of traps) and methods (pitfall trapping) were identical, conforming to the Globenet protocol. Assemblage composition and diversity patterns were evaluated. Diversity relationships were analysed by the Rényi diversity ordering method considering all ground beetles and - separately - the forest specialist species. Taxonomic homogenization was examined by multivariate methods using assemblage similarities. Results: Overall biodiversity (compared by species richness and diversity ordering) showed inconsistent trends by either urbanization intensity or by geographic position. However, when only forest species were compared, diversity was higher in the original rural (forested) areas than in urban forest fragments. Within-country similarities of carabid assemblages were always higher than within-urbanization stage similarities. Main conclusions: Urbanization does not appear to cause a decrease in ground beetle diversity . per se. Forest species decline as urbanization intensifies but this trend is masked by an influx of non-forest species. The rural faunas were more similar to the urban ones within the same location than similar urbanization stages were to each other, indicating that urbanization did not homogenize the taxonomic composition of ground beetle faunas across the studied locations. © 2009 Blackwell Publishing Ltd.
Kjaergaard P.C.,University of Aarhus
ISIS | Year: 2012
Fossils have been traded for centuries. Over the past two hundred years the market has developed into an organized enterprise, with fossils serving multiple functions as objects of scientific study, collectors' items, and investments. Finding fossils, digging them up or purchasing them, transporting, studying, and conserving them, and putting them on display was and still is expensive. Since the early nineteenth century, funding bodies, academic institutions and museums, philanthropists, dealers, collectors, amateurs, and professional paleontologists have constituted elaborate networks driven by collaboration, necessity, ambition, accolades, and capital to generate knowledge and produce geological artifacts, increasing our understanding of the natural world, advancing careers and institutions, and contributing to personal fortunes. The emergence of paleoanthropology as a scientific discipline around 1900 generated a scientific focus on the human story that was easy to sell. The scarcity of ancient human remains made it close to impossible for a commercial market to evolve, yet finding them required serious funding. Elaborate schemes for financing expeditions and excavations went hand in hand with individual aspirations, patronage, philanthropy, networks, and alliance building, as concession rights and access to sponsors were objects of regular political intrigues and often bitter disputes. © 2012 by The History of Science Society. All rights reserved.
Ditzel J.,University of Aarhus
Current diabetes reviews | Year: 2010
The pathogenesis of diabetic late complications (DLC) is multifactorial. Studies of mechanisms leading to early functional microvascular changes in retina and kidneys point towards a disturbance in the metabolism of inorganic phosphate (Pi) in diabetes. Since tissue hypoxia and reduced high energy phosphates may be important factors in the development of DLC, the influence of Pi concentration on the metabolism and function of the erythrocytes and renal tubular cells, as well as the relationship of the concentration of Pi to total oxygen consumption, have been reviewed. While extensive research data in non-diabetic conditions support the suggestion, that the Pi concentration is a determining factor in regulation of metabolism and rate of oxygen consumption, diabetes shows the opposite behavior. In diabetes, the highest oxygen consumption is associated with the lowest concentration of Pi. Many conventionally-treated juvenile diabetic patients respond as if their tissues were in a state of chronic hypoxia. A disturbance in phosphate handling occurs in the kidney tubules, where the excessive sodium-dependent glucose entry in diabetics depolarizes the electrochemical sodium gradient and consequently impairs inorganic phosphate reabsorption. Similar changes may occur in other cells and tissues in which glucose entry is not controlled by insulin, and particularly in poorly-regulated diabetic patients in whom long-term vascular complications are more likely.
Bendixen K.H.,University of Aarhus
Journal of orofacial pain | Year: 2010
To investigate the effect of a low dose of intramuscular (im) ketorolac compared with lidocaine (LA) in a double-blinded, randomized, and controlled trial. Twelve healthy women participated in three sessions and received two injections into their right masseter muscle per session. The first injections contained hypertonic saline (HS, 5% in 0.2 mL) to induce muscle pain. The second injections were given 30 minutes later and contained, together with HS, either ketorolac (3 mg in 0.2 mL), LA (2% lidocaine in 0.2 ml), or HS alone (control). HS-evoked pain intensity was scored on a 0 to 10 electronic visual analog scale (VAS) measuring peak, duration, and area under the curve (AUC). Pressure pain thresholds (PPT), pressure pain tolerance levels (PPTOL), and pain on palpation (POP) were determined bilaterally on the masseter muscle before and 5, 15, and 25 minutes after the injections. Maximum jaw opening (MJO) was measured at baseline and every 10 minutes after. McGill Pain Questionnaire (MPQ) scores and the extent of the HS-evoked pain (pain drawings) were recorded at baseline, 2 minutes after the first and second injections, and every 10 minutes during the entire experimental session. There were no differences between the three sessions in HS-evoked pain measures from the first injection (P > .05). During the second injection, HS + LA demonstrated significantly lower VAS peak, duration, and AUC scores than control and HS + ketorolac (P < .001). In the HS + ketorolac session, the VAS AUC was significantly lower than in the control session (P < .005). The sessions had no main effect on PPT, PPTOL, POP, MJO, or pain drawings (P > .05). A low dose of im ketorolac has a significant and immediate analgesic effect on HS-evoked jaw muscle pain but significantly less than LA. A local anesthetic-like effect may be the underlying mechanism.
Simovska V.,University of Aarhus
Health Education | Year: 2012
Purpose: The editorial aims to provide a brief overview of the individual contributions to the special issue, and a commentary positioning the contributions within research relating to the health-promoting schools initiative in Europe. Design/methodology/approach: The members of the Schools for Health in Europe Research Group were invited to submit their work addressing processes and outcomes in school health promotion to this special issue of Health Education. Additionally, an open call for papers was published on the Health Education web site. Following the traditional double blind peer review process, nine submissions were accepted for publication. Five of these are selected to be published in this issue and the rest will be published in a future issue of the journal. Findings: The five articles in this issue take a comprehensive approach to health promotion in schools and reflect on the related processes and outcomes. Although diverse in focus and research methodology, the five contributions all emphasise that the question about the outcomes of the health-promoting schools cannot, and should not be limited to narrowly defined health outcomes achieved through single health-promotion interventions. Directly or indirectly the articles reiterate the idea that health promotion in schools needs to be linked with the core task of the school - education, and to the values inherent to education, such as inclusion, democracy, participation and influence, critical literacy and action competence in relation to health. Originality/value: This special issue endorses the idea that health promotion in schools would do well to reconnect with the traditions of educational theory and to develop innovative forms of educational practices and interventions in the face of complex societal challenges concerning health and health promotion. It can be beneficial for stakeholders who work towards school based health promotion, assisting them in bridging the gap between health and education sector. © Emerald Group Publishing Limited.
Starrfelt R.,Copenhagen University |
Habekost T.,Copenhagen University |
Gerlach C.,University of Aarhus
Cortex | Year: 2010
Whether pure alexia is a selective disorder that affects reading only, or if it reflects a more general visual disturbance, is highly debated. We have investigated the selectivity of visual deficits in a pure alexic patient (NN) using a combination of psychophysical measures, mathematical modelling and more standard experimental paradigms. NN's naming and categorization of line drawings were normal with regards to both errors and reaction times (RTs). Psychophysical experiments revealed that NN's recognition of single letters at fixation was clearly impaired, and recognition of single digits was also affected. His visual apprehension span was markedly reduced for letters and digits. His reduced visual processing capacity was also evident when reporting letters from words. In an object decision task with fragmented pictures, NN's performance was abnormal. Thus, even in a pure alexic patient with intact recognition of line drawings, we find evidence of a general visual deficit not selective to letters or words. This finding is important because it raises the possibility that other pure alexics might have similar non-selective impairments when tested thoroughly. We argue that the general visual deficit in NN can be accounted for in terms of inefficient build-up of sensory representations, and that this low level deficit can explain the pattern of spared and impaired abilities in this patient. © 2009 Elsevier Srl. All rights reserved.
Zinner N.T.,University of Aarhus
Few-Body Systems | Year: 2014
The study of quantum mechanical few-body systems is a century old pursuit relevant to countless subfields of physics. While the two-body problem is generally considered to be well-understood theoretically and numerically, venturing to three or more bodies brings about complications but also a host of interesting phenomena. In recent years, the cooling and trapping of atoms and molecules has shown great promise to provide a highly controllable environment to study few-body physics. However, as is true for many systems where few-body effects play an important role the few-body states are not isolated from their many-body environment. An interesting question then becomes if or (more precisely) when we should consider few-body states as effectively isolated and when we have to take the coupling to the environment into account. Using some simple, yet non-trivial, examples I will try to suggest possible approaches to this line of research. © 2014 Springer-Verlag Wien.
Bjerregaard T.,University of Aarhus
Technovation | Year: 2010
Research on university-industry (UI) collaboration has addressed how cultural differences between firms and universities tend to impede knowledge exchange and impose challenges on project control if not properly addressed. Relatively little research has examined in-depth how changing institutional logics of R&D practice shape concrete UI collaborations at the micro-level of interacting researchers. The purpose of this study is to examine how conflicting and converging institutional logics of R&D work enable and constrain the process of R&D collaboration between small and medium sized enterprises (SMEs) and public university departments. This qualitative study covers the total population of public university departments and firms involved in collaborative research projects sponsored by a programme under the National Strategic Research Council (NSRC) in Denmark. The findings show that many of the collaborating researchers experienced an institutional convergence constituting a shared cultural space for knowledge exchange and communication in their joint projects. In some cases this lack of normative conflict was due to a blurring of institutional logics governing R&D in the two sectors. Furthermore, some researchers were able to use their social skills to bridge perceived institutional gaps. Implications for future research and UI collaboration are addressed. © 2009 Elsevier Ltd. All rights reserved.
Bonefeld-Jorgensen E.C.,University of Aarhus
Rural and remote health | Year: 2010
CONTEXT: Since 1997 the Arctic Monitoring and Assessment Programme (AMAP) has produced integrated assessment reports on the status of and trends in environmental persistent organic pollutants (POPs) in the Arctic ecosystem. Three reports on biomonitoring POPs and their health risks for Arctic populations were published in 1998, 2002, and 2009. ISSUE: The present review summarizes data from Greenland on human monitoring of biomarkers of POP exposure and bioaccumulation and the determination of biomarkers for POP effects. The review focuses on hormone disruptive potentials and some genetic sensitivity biomarkers. The overview covers Greenlandic studies from 2000 to 2006. LESSONS LEARNED: The Greenland biomonitoring studies showed general geographical and gender differences of bioaccumulated serum POP levels, which were primarily related to diet and lifestyle. A high intake of traditional Greenlandic diet (eg seal, whale, polar bear, and seabirds) together with smoking caused higher blood concentrations of POPs. The highest POP values were found on the east coast of Greenland. The receptor effect studies showed a general inverse relationship between high serum POP concentration and estrogen receptor (ER) and Ah-receptor (AhR) transactivity; in addition for men in the two West Greenlandic districts, Nuuk and Sisimiut, a trend towards increased induced AR activity was found. An observed trend to an opposite direction between the dioxin-like AhR and ER activity supports the perception of that dioxins exert an antiestrogen effect. In conclusion, the actual mixtures of serum POPs in Greenlandic Inuit have an endocrine disrupting potential. Comparisons between European and Greenlandic male serum POP levels showed significantly higher levels in Inuit; however, in the same study Inuit had significantly lower sperm DNA damage. Further studies are required to elucidate whether the serum POP related effects on hormone receptors and/or AhR are explanatory factors. 'The Arctic dilemma' is that along with the intake of the Greenlandic traditional diet that contains POPs, there are also a number of important nutrients, such as trace elements/antioxidants and marine unsaturated fatty acids which have favorable effects on health. However, a number of studies suggest that an increase in Western food items in the diet can lead to other health risks, such as the metabolic syndrome and its sequels increase in weight, hypertension, diabetes type 2, cardiovascular disease, and cancer, including breast cancer. To elucidate these aspects further studies are required, including those into biomarkers for exposure and effects, epigenetic contexts and the determination of relevant genetic polymorphisms, case-control as well as generation studies. Finally, there is a need for the development of new biomarkers to study the potential POP effects that inhibit the immune system and affect the development of the central nervous system.
Palmgren M.G.,Copenhagen University |
Nissen P.,University of Aarhus
Annual Review of Biophysics | Year: 2011
P-type ATPases form a large superfamily of cation and lipid pumps. They are remarkably simple with only a single catalytic subunit and carry out large domain motions during transport. The atomic structure of P-type ATPases in different conformations, together with ample mutagenesis evidence, has provided detailed insights into the pumping mechanism by these biological nanomachines. Phylogenetically, P-type ATPases are divided into five subfamilies, P1P5. These subfamilies differ with respect to transported ligands and the way they are regulated. © 2011 by Annual Reviews. All rights reserved.
Pollach I.,University of Aarhus
Business Strategy and the Environment | Year: 2014
Departing from agenda-setting theory, this paper explores whether environmental content in newspapers is related to corporate environmental agendas presented in corporate environmental reports and annual reports. Based on a sample of 1668 corporate reports published between 1997 and 2008, this paper compares corporate reporting against environmental news content over the same period with time lags of one and two years as well as without time lags. The results suggest that the media agenda and the corporate environmental agenda mirror each other. The results further suggest that, for some issues, there may be an impact of the news media agenda on corporate environmental agendas, but not vice versa. © 2013 John Wiley & Sons, Ltd and ERP Environment.
Kaspersen M.D.,University of Aarhus
Andrology | Year: 2013
It remains unknown whether human papillomaviruses (HPVs) or human herpesviruses (HHVs) in semen affect sperm DNA integrity. We investigated whether the presence of these viruses in semen was associated with an elevated sperm DNA fragmentation index. Semen from 76 sperm donors was examined by a PCR-based hybridization array that identifies all HHVs and 35 of the most common HPVs. Sperm DNA integrity was determined by the sperm chromatin structure assay. HPVs or HHVs, or both, were found in 57% of semen samples; however, sperm DNA fragmentation index was not increased in semen containing these viruses. © 2013 American Society of Andrology and European Academy of Andrology.
Christensen J.,Aarhus University Hospital |
Christensen J.,University of Aarhus
Epilepsia | Year: 2012
Summary Traumatic brain injury (TBI) is a potentially preventable cause of epilepsy. Increasing incidence among army personnel and the high incidence among children and young people raise concern. This article presents a review of selected studies dealing with the risks of TBI and the risk of posttraumatic epilepsy in humans. The incidence of persons admitted to hospital with TBI has decreased in developed countries in recent years. However, there is little change in TBI-associated deaths, and the decrease in hospitalization may merely reflect that more people with head injury are cared for on an outpatient basis. It is clear that epilepsy is a frequent consequence of brain injury, even many years after the injury. However, several well-controlled studies have been unable to identify therapies that prevent the development of epilepsy after TBI. Posttraumatic epilepsy has significant implications for the affected individuals, family, and society. Despite several interventions used to prevent posttraumatic epilepsy, the only proven "intervention" to date is to prevent TBI from occurring. © Wiley Periodicals, Inc. © 2012 International League Against Epilepsy.
Otzen D.E.,University of Aarhus
Protein Engineering, Design and Selection | Year: 2011
The four-helical transmembrane protein DsbB (disulfide bond reducing protein B) folds and unfolds reversibly in mixed anionic/non-ionic micelles, consisting of an unfolding intermediate I and a rate-limiting transition state (TS) between I and the denatured state D. Here, I describe the analysis of the folding behavior of 12 different alanine-scanning mutants of DsbB. For all mutants, TS is as compact as D and there is an accelerating increase in compaction as the protein proceeds to I and the native state. This unusual pattern of consolidation may reflect significant amounts of secondary structure in D, analogous to a classical folding intermediate. Unexpectedly, an increase in apolar surface area upon mutation is stabilizing whereas an increase in polar surface area is destabilizing. This effect is probably dominated by the effect of the mutations on the structure of the denatured state. I observe clear Hammond postulate behavior, in which a destabilization of I moves it closer to D. φ-Value analysis indicates that in TS, a folding nucleus consisting of two to three residues with φ-values of >0.5 forms at one end of the transmembrane helices, which expands to include residues closer to the middle of the protein in I. Thus, folding proceeds from a highly polarized starting point. © The Author 2010. Published by Oxford University Press. All rights reserved.
Rattan S.I.S.,University of Aarhus
Annals of the New York Academy of Sciences | Year: 2010
Strategies for testing and developing effective means of intervention, prevention, and modulation of aging incorporate means to minimize the occurrence and accumulation of molecular damage, to reduce molecular heterogeneity, and to evaluate the relevance of the type and extent of damage with respect to its role in aging and age-related diseases. One such approach is that of mild stress-induced hormesis, which stimulates maintenance and repair systems and strengthens the homeodynamic space of cells and organisms. Hormesis through mild heat shock, natural and synthetic hormetins, and other stressors brings about several antiaging effects in human fibroblasts, keratinocytes, and telomerase-immortalized bone marrow stem cells. Depending on the cell type, these antiaging hormetic effects include extension of replicative life span, enhanced proteasomal activities, increased chaperone levels, and improved wound healing, angiogenesis, and differentiation. The main molecular pathways for achieving such hormetic effects are through targeting the processes for the repair and removal of molecular damage, which can slow aging. © 2010 New York Academy of Sciences.
Hesse M.,University of Aarhus
Addictive Behaviors | Year: 2010
Attention deficit and hyperactivity disorder has been associated with poor outcome in studies of substance use disorders. This study aimed to assess the course of self-reported symptoms of both attention deficit and hyperactivity among adults presenting for treatment for substance use disorders. A sample of 75 substance abusers were assessed after they were admitted to a centralized intake unit, and followed at 3 and 6 months after intake by independent interviewers (follow-up rate 81%). Symptoms of attention deficit and hyperactivity were assessed with the Adult Self-report Scale for ADHD (ASRS). Both types of symptoms declined significantly during follow-up, but attention symptoms had a high intraclass correlation (0.79), and hyperactivity had a moderate intraclass correlation (0.64). Both baseline attention deficit and hyperactivity symptoms were associated with worse work and social adjustment after controlling for baseline functioning. Hyperactivity was associated with poorer substance use outcomes at the trend level. In conclusion, both dimensions of ADHD contribute to worse functioning during early treatment for substance abusers, and the ASRS is a reasonably stable measure of ADHD symptoms during early recovery. © 2009 Elsevier Ltd. All rights reserved.
Levinsen J.,Monash University |
Parish M.M.,Monash University |
Parish M.M.,London Center for Nanotechnology |
Bruun G.M.,University of Aarhus
Physical Review Letters | Year: 2015
We investigate the zero-temperature properties of an impurity particle interacting with a Bose-Einstein condensate (BEC), using a variational wave function that includes up to two Bogoliubov excitations of the BEC. This allows one to capture three-body Efimov physics, as well as to recover the first nontrivial terms in the weak-coupling expansion. We show that the energy and quasiparticle residue of the dressed impurity (polaron) are significantly lowered by three-body correlations, even for weak interactions where there is no Efimov trimer state in a vacuum. For increasing attraction between the impurity and the BEC, we observe a smooth crossover from atom to Efimov trimer, with a superposition of states near the Efimov resonance. We furthermore demonstrate that three-body loss does not prohibit the experimental observation of these effects. Our results thus suggest a route to realizing Efimov physics in a stable quantum many-body system for the first time. © 2015 American Physical Society.
Bruun G.M.,University of Aarhus |
Pethick C.J.,Niels Bohr Institute |
Physical Review Letters | Year: 2011
We show that puzzling recent experimental results on spin diffusion in a strongly interacting atomic gas may be understood in terms of the predicted spin diffusion coefficient for a generic strongly interacting system. Three important features play a central role: (a) Fick's law for diffusion must be modified to allow for the trapping potential; (b) the diffusion coefficient is inhomogeneous, due to the density variations in the cloud; and (c) the diffusion approximation fails in the outer parts of the cloud, where the mean free path is long. © 2011 American Physical Society.
Sorensen L.K.,University of Aarhus
Biomedical Chromatography | Year: 2012
Metformin is an anti-diabetic drug in the biguanide class which also includes phenformin and buformin. Because of the potential adverse effects of the biguanides, a reliable liquid chromatography-tandem mass spectrometry method using pneumatically assisted electrospray ionization was developed for the quantification of the drugs in both live and post-mortem human whole blood. The blood proteins were precipitated by the addition of a mixture of methanol and acetonitrile, and the extract was cleaned up by cation-exchange solid-phase extraction to eliminate ion suppression effects. The separation was performed by hydrophilic interaction liquid chromatography. Matrix-matched calibrants combined with isotope dilution of metformin were used for calibration. The detection limits were 0.01mg/L for metformin and phenformin and the relative intra-laboratory reproducibility standard deviations were less than 6% at concentrations of 1-10mg/L. The mean true recoveries were greater than 86%. Copyright © 2011 John Wiley & Sons, Ltd.
Ciliberto S.,Ecole Normale Superieure de Lyon |
Imparato A.,University of Aarhus |
Naert A.,Ecole Normale Superieure de Lyon |
Tanase M.,Ecole Normale Superieure de Lyon
Physical Review Letters | Year: 2013
We report an experimental and theoretical analysis of the energy exchanged between two conductors kept at different temperature and coupled by the electric thermal noise. Experimentally we determine, as functions of the temperature difference, the heat flux, the out-of-equilibrium variance, and a conservation law for the fluctuating entropy, which we justify theoretically. The system is ruled by the same equations as two Brownian particles kept at different temperatures and coupled by an elastic force. Our results set strong constraints on the energy exchanged between coupled nanosystems held at different temperatures. © 2013 American Physical Society.
Yang Y.,University of Aarhus
Genetics research | Year: 2011
Over recent years, statistical support for the presence of genetic factors operating at the level of the environmental variance has come from fitting a genetically structured heterogeneous variance model to field or experimental data in various species. Misleading results may arise due to skewness of the marginal distribution of the data. To investigate how the scale of measurement affects inferences, the genetically structured heterogeneous variance model is extended to accommodate the family of Box-Cox transformations. Litter size data in rabbits and pigs that had previously been analysed in the untransformed scale were reanalysed in a scale equal to the mode of the marginal posterior distribution of the Box-Cox parameter. In the rabbit data, the statistical evidence for a genetic component at the level of the environmental variance is considerably weaker than that resulting from an analysis in the original metric. In the pig data, the statistical evidence is stronger, but the coefficient of correlation between additive genetic effects affecting mean and variance changes sign, compared to the results in the untransformed scale. The study confirms that inferences on variances can be strongly affected by the presence of asymmetry in the distribution of data. We recommend that to avoid one important source of spurious inferences, future work seeking support for a genetic component acting on environmental variation using a parametric approach based on normality assumptions confirms that these are met.
Webb R.T.,University of Manchester |
Kontopantelis E.,University of Manchester |
Doran T.,University of Manchester |
Qin P.,University of Aarhus |
And 2 more authors.
Archives of General Psychiatry | Year: 2012
Context: Most previous studies have examined suicide risk in relation to a single physical disease. Objectives: To estimate relative risk across a range of physical diseases, to assess the confounding effect of clinical depression and effect modification by sex and age, and to examine physical illness multimorbidity. Design: Nested case-control study. Setting: Family practices (n=593) registered with the General Practice Research Database from January 1, 2001, through December 31, 2008. The case-control data were drawn from approximately 10.6 million complete patient records, pertaining to approximately 8% of the total population of the United Kingdom, with complete linkage to national mortality records. Participants: A total of 873 adult suicide cases and 17 460 living controls matched on age and sex were studied. The reference group for relative risk estimation consisted of people without any of the specific physical illnesses examined. Main Outcome Measures: Suicide and open verdicts. Results: Among all patients, coronary heart disease, stroke, chronic obstructive pulmonary disease, and osteoporosis were linked with elevated suicide risk, and, with the exception of osteoporosis, the increase was explained by clinical depression. The only significantly elevated risk in men was with osteoporosis. Female effect sizes were greater, with 2- or 3-fold higher risk found amongwomen diagnosed as having cancer, coronary heart disease, stroke, chronic obstructive pulmonary disease, and osteoporosis. In women with cancer and coronary heart disease, a significant elevation persisted after adjustment for depression. Overall, heightened risk was confined to physically ill women younger than 50 years and to older women with multiple physical diseases. Conclusions: Our findings indicate that clinical depression is a strong confounder of increased suicide risk among physically ill people. They also demonstrate an independent elevation in risk linked with certain diagnoses, particularly among women. Health care professionals working across all medical specialties should be vigilant for signs of undetected psychological symptoms. ©2012 American Medical Association. All rights reserved.
Nemesio A.,Federal University of Uberlandia |
Rasmussen C.,University of Aarhus
Zootaxa | Year: 2011
The taxonomic status (or the taxonomic status of the onomatophores) of seven nomina are revised: Eulaema meriana (Olivier, 1789), Euglossa piliventris Guérin-Méneville, 1844, Exaerete appendiculata (Romand, 1849), Exaerete subcornuta (Romand, 1849), Eufriesea danielis (Schrottky, 1907), Euglossa fimbriata Moure, 1968, and Eufriesea yepezi (Moure, 2000). Lectotype is designated for Euglossa piliventris Guérin-Méneville, 1844. Neotypes are designated for Apis meriana Olivier, 1789 and Apis dimidiata Fabricius, 1793 based on the same specimen and A. dimidiata Fabricius, 1793 became an objective synonym of A. meriana Olivier, 1789. Chrysantheda subcornuta Romand, 1849 is shown to be a senior objective synonym of Chrysantheda appendiculata Romand, 1849 and their synonymy under Exaerete dentata (Linnaeus, 1758) is questioned and discussed. Eumorpha combinata danielis Schrottky, 1907 is confirmed as a junior subjective synonym of Eufriesea auriceps (Friese, 1899), but the status of its onomatophore is reconsidered. Moreover, a long overlooked Euglossa dentata var. maxima Romand, 1849, nom. nud. and Euplusia yepezi Moure, 2000, nom. nud. are discussed for the first time. Both nomina Euglossa fimbriata Moure, 1968 and Euglossa fimbriata Rebêlo & Moure, 1996 are available, but the latter is permamently invalid as a junior primary homonym of the former. An updated catalogue of all orchid bee nomina is also provided. Copyright © 2011, Magnolia Press.
Nissen P.E.,University of Aarhus |
Schuster W.J.,National Autonomous University of Mexico
Astronomy and Astrophysics | Year: 2010
Aims: Precise abundance ratios are determined for 94 dwarf stars with 5200 < T eff < 6300K, -1.6 < [Fe/H] < -0.4, and distances D ≲ 335 pc. Most of them have halo kinematics, but 16 thick-disk stars are included. Methods: Equivalent widths of atomic lines are measured from VLT/UVES and NOT/FIES spectra with resolutions R ≃ 55 000 and R ≃ 40 000, respectively. An LTE abundance analysis based on MARCS models is applied to derive precise differential abundance ratios of Na, Mg, Si, Ca, Ti, Cr, and Ni with respect to Fe. Results: The halo stars fall into two populations, clearly separated in [α/Fe], where α refers to the average abundance of Mg, Si, Ca, and Ti. Differences in [Na/Fe] and [Ni/Fe] are also present with a remarkably clear correlation between these two abundance ratios. Conclusions: The "high-α" stars may be ancient disk or bulge stars "heated" to halo kinematics by merging satellite galaxies or they could have formed as the first stars during the collapse of a proto-Galactic gas cloud. The kinematics of the "low-α" stars suggest that they have been accreted from dwarf galaxies, and that some of them may originate from the ωCen progenitor galaxy. © 2010 ESO.
Haubek D.,University of Aarhus
APMIS | Year: 2010
For many years, attention has been given to the oral bacterium Aggregatibacter actinomycetemcomitans, as a species possibly implicated in the etiology of aggressive periodontitis in adolescents. One of the major virulence factors of A. actinomycetemcomitans is the leukotoxin which is able to kill important cells of the immune system. © 2010 APMIS.
Finnemann N.O.,University of Aarhus
Journal of Documentation | Year: 2014
Purpose: The purpose of this paper is to improve comprehension of some of the intricate interrelations between research libraries, the role of media and the knowledge production system. Design/methodology/approach: This paper establishes arguments from a historical analysis of stages in the conceptual development of digital media and stages in the digitization of library functions. The historical approach leads to some discussions and forecasts of the future of research libraries. Findings: Digital media have a disruptive, revolutionary potential, but path dependency is often a modifying component in the historical development. This is demonstrated in different stages of the development of the interrelationship between digitization, digital media and research libraries. Digital media become disruptive due to the strength of the historical dynamic, rather than as a result of particular agencies. Today the historical dynamic has reached a point where all institutions concerned with knowledge handling will have to redefine themselves. Research libraries are gradually incorporated into a number of new "research infrastructures" which are being built around different kinds of data materials, and each research library may specialize according to some sort of coordinated criteria. Originality/value: This paper demonstrates new openings to a theoretical and conceptual understanding of the interrelationship between digital media and developments of research libraries. © Emerald Group Publishing Limited.
Jespersen K.R.,University of Aarhus
Journal of Product Innovation Management | Year: 2012
The new product development (NPD) process is a sequence of stages and gates. Each stage consists of NPD activities that provide NPD managers with information input about the new product project progression. Information input is used for review decisions at gates. Over the course of an NPD process, managers learn about a new product project as to ensure successful launch. The view is that a new product project is shaped by the path of NPD activities it has traveled. Because learning is assumed to take place over the course of the NPD process, stage-to-stage information dependency is an assumption of NPD research. A concern raised is that development activities for each NPD stage are rigorously followed by NPD managers. In other words, stage-to-stage information dependency may potentially trap NPD managers rather than create effective learning from end to end of the development process. The purpose of this paper is to explore the assumption of stage-to-stage information dependency in NPD. The investigated research questions are whether the selection of NPD activities is linked between stages and whether these information dependencies strengthen NPD gate decisions. For the information dependencies identified in the study, the innovation experience characteristics of NPD managers pursuing them and the influence of information dependencies on NPD gate decisions are analyzed so as to provide insights for a discussion of information dependency versus information independency in the NPD process. The applied research method is an experiential simulation of NPD gate decisionmaking-NPDGATES. One hundred thirty-one NPD managers from international product development strategic business units (SBUs) situated in Denmark participated in the study. Logistic regressions were conducted as the basis for the calculation of stage-to-stage information dependency probabilities. Based on the study findings, the assumption about information dependency in the NPD process held by NPD research is found to be flawed. End-to-end information paths in the NPD process are rare. Further, market condition changes are found to significantly influence the stage-to-stage information dependencies demonstrated by NPD managers. It seems that competition becomes a reassurance of NPD efforts. Also, the results show that NPD experience creates inflexibility in relation to the selection of NPD activities. The need for strict process management is strong among experienced NPD managers. In relation to NPD gates, the results show that information dependencies increase priority given to financial decision criteria at gates and lower priority given to customer and market decision criteria. Overall, stage-to-stage information dependency seems to create inflexibility that hinders successful NPD process implementation. © 2012 Product Development & Management Association.
Sarkissian G.,University of Aarhus
Nuclear Physics B | Year: 2011
In this paper we construct defects in coset G/H theory. Canonical quantization of the gauged WZW model G/H with N defects on a cylinder and a strip is performed and the symplectomorphisms between the corresponding phase spaces and those of double Chern-Simons theory on an annulus and a disc with Wilson lines are established. Special attention to topological coset G/G has been paid. We prove that a G/G theory on a cylinder with N defects coincides with Chern-Simons theory on a torus times the timeline R with 2N Wilson lines. We have shown also that a G/G theory on a strip with N defects coincides with Chern-Simons theory on a sphere times the time-line R with 2N + 4 Wilson lines. This particular example of topological field theory enables us to penetrate into a general picture of defects in semisimple 2D topological field theory. We conjecture that defects in this case described by a 2-category of matrices of vector spaces and that the action of defects on boundary states is given by the discrete Fourier-Mukai transform. © 2011 Elsevier B.V.
Assent I.,University of Aarhus
Wiley Interdisciplinary Reviews: Data Mining and Knowledge Discovery | Year: 2012
High-dimensional data, i.e., data described by a large number of attributes, pose specific challenges to clustering. The so-called 'curse of dimensionality', coined originally to describe the general increase in complexity of various computational problems as dimensionality increases, is known to render traditional clustering algorithms ineffective. The curse of dimensionality, among other effects, means that with increasing number of dimensions, a loss of meaningful differentiation between similar and dissimilar objects is observed. As high-dimensional objects appear almost alike, new approaches for clustering are required. Consequently, recent research has focused on developing techniques and clustering algorithms specifically for high-dimensional data. Still, open research issues remain. Clustering is a data mining task devoted to the automatic grouping of data based on mutual similarity. Each cluster groups objects that are similar to one another, whereas dissimilar objects are assigned to different clusters, possibly separating out noise. In this manner, clusters describe the data structure in an unsupervised manner, i.e., without the need for class labels. A number of clustering paradigms exist that provide different cluster models and different algorithmic approaches for cluster detection. Common to all approaches is the fact that they require some underlying assessment of similarity between data objects. In this article, we provide an overview of the effects of high-dimensional spaces, and their implications for different clustering paradigms. We reviewmodels and algorithms that address clustering in high dimensions, with pointers to the literature, and sketch open research issues. We conclude with a summary of the state of the art. © 2012 Wiley Periodicals, Inc.
Bollingtoft A.,University of Aarhus
Technovation | Year: 2012
The purpose of this study is to report the findings of an exploratory study of two self-generated, entrepreneurial-enabled environments labeled 'bottom-up business incubators. They are characterized by being jointly established by the entrepreneurs, they are not supported by public or private funds, thus, they carry no costs for society. The bottom-up business incubators share the same overall traits as for business incubators as described in the literature, e.g. co-location of businesses and access to shared equipment, but in contrast to traditional business incubators, it is characterized by being based on mutual recognition of the value of networking as well as cooperation among the firms. Based on observations and interviews with tenant firms, the study identifies networking and cooperation activities among the entrepreneurs. Furthermore, the study investigates the role of the bottom-up business incubator in terms of facilitating and enabling the conditions for internal networking and cooperation among the entrepreneurs, thus, how the business incubators become a formal mechanism for embedding the companies in entrepreneurial networks. The closing section of the paper addresses the implications for research and practitioners. © 2011 Elsevier Ltd. All rights reserved.
Vestergaard E.T.,University of Aarhus
American journal of physiology. Endocrinology and metabolism | Year: 2013
Ghrelin is a gut-derived peptide and an endogenous ligand for the ghrelin receptor. Intravenous infusion of ghrelin induces insulin resistance and hyperglycemia and increases circulating levels of nonesterified free fatty acids. Our objective was to investigate whether the metabolic effects are mediated directly by ghrelin in skeletal muscle and adipose (peripheral and central) tissues. Ten healthy men (24.9 ± 1.3 yr) received 300 min of supraphysiological ghrelin administration by microdialysis catheters in skeletal muscle and adipose tissues in a randomized, single-blind, and placebo-controlled study. Microdialysis perfusates were analyzed every 30 min for glucose, glycerol, and lactate during both a basal period and a hyperinsulinemic euglycemic clamp. The primary outcome measures were interstitial concentrations of glucose, glycerol, and lactate in skeletal muscle and adipose tissues. Interstitial concentrations of glucose were similar in skeletal muscle, peripheral, and central adipose tissue in the basal period. During hyperinsulinemia, interstitial concentrations of glucose in skeletal muscle decreased in response to ghrelin exposure [2.84 ± 0.25 (ghrelin) vs. 3.06 ± 0.26 mmol/l (placebo), P = 0.04]. Ghrelin exposure did not impact on interstitial concentrations of glycerol and lactate. We conclude that ghrelin administration into skeletal muscle decreases interstitial concentrations of glucose during euglycemic hyperinsulinemia, which is indicative of increased insulin sensitivity without any effects on interstitial glycerol levels in either muscle or adipose tissue. These data contrast with the metabolic effects of ghrelin observed after systemic exposure and suggest the existence of a second messenger that remains to be identified.
Bruun G.M.,University of Aarhus
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014
The Higgs mode corresponds to the collective motion of particles due to the vibrations of an invisible field. It plays a fundamental role in our understanding of both low- and high-energy physics, giving elementary particles their mass and leading to collective modes in condensed-matter and nuclear systems. The Higgs mode has been observed in a limited number of table-top systems, where it however is characterized by a short lifetime due to decay into a continuum of modes. A major goal which has remained elusive so far is, therefore, to realize a long-lived Higgs mode in a controllable system. Here, we show how an undamped Higgs mode can be observed unambiguously in a Fermi gas in a two-dimensional trap, close to a quantum phase transition between a normal and a superfluid phase. We develop a first-principles theory of the pairing and the associated collective modes, which is quantitatively reliable when the pairing energy is much smaller than the trap level spacing, yet simple enough to allow the derivation of analytical results. The theory includes the trapping potential exactly, which is demonstrated to stabilize the Higgs mode by making its decay channels discrete. It is shown to be realistic to realize the proposed system using atoms in microtraps. The unrivaled flexibility of atomic gases combined with the quantitatively accurate theory opens the door to a systematic study of the Higgs mode, including the role of confinement and finite-size effects. © 2014 American Physical Society.
Raben A.,Copenhagen University |
Richelsen B.,University of Aarhus
Current Opinion in Clinical Nutrition and Metabolic Care | Year: 2012
Purpose of Review: Artificial sweeteners can be a helpful tool to reduce energy intake and body weight and thereby risk for diabetes and cardiovascular diseases (CVD). Considering the prevailing diabesity (obesity and diabetes) epidemic, this can, therefore, be an important alternative to natural, calorie-containing sweeteners. The purpose of this review is to summarize the current evidence on the effect of artificial sweeteners on body weight, appetite, and risk markers for diabetes and CVD in humans. Recent Findings: Short-term intervention studies have shown divergent results wrt appetite regulation, but overall artificial sweeteners cannot be claimed to affect hunger. Data from longer term intervention studies are scarce, but together they point toward a beneficial effect of artificial sweeteners on energy intake, body weight, liver fat, fasting and postprandial glycemia, insulinemia, and/or lipidemia compared with sugar. Epidemiological studies are not equivocal, but large cohort studies from the USA point toward decreased body weight and lower risk of type-2 diabetes and coronory heart diseases with increased intake of artificial sweeteners compared with sugar. Summary: Artificial sweeteners, especially in beverages, can be a useful aid to maintain reduced energy intake and body weight and decrease risk of type-2 diabetes and CVD compared with sugars. However, confirmative long-term intervention trials are still needed. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Lee S.,University of Aarhus
Oncogene | Year: 2015
Increased metabolism and insufficient blood supply cause acidic waste product accumulation in solid cancers. During carcinogenesis, cellular acid extrusion is upregulated but the underlying molecular mechanisms and their consequences for cancer growth and progression have not been established. Genome-wide association studies have indicated a possible link between the Na+,HCO3-cotransporter NBCn1 (SLC4A7) and breast cancer. We tested the functional consequences of NBCn1 knockout (KO) for breast cancer development. NBCn1 protein expression increased 2.5-fold during breast carcinogenesis and was responsible for the increased net acid extrusion and alkaline intracellular pH of breast cancer compared with normal breast tissue. Genetic disruption of NBCn1 delayed breast cancer development: tumor latency was ~50% increased while tumor growth rate was ~65% reduced in NBCn1 KO compared with wild-type (WT) mice. Breast cancer histopathology in NBCn1 KO mice differed from that in WT mice and included less aggressive tumor types. The extracellular tumor microenvironment in NBCn1 KO mice contained higher concentrations of glucose and lower concentrations of lactate than that in WT mice. Independently of NBCn1 genotype, the cleaved fraction of poly(ADP-ribose) polymerase (PARP)-1 and expression of monocarboxylate transporter (MCT)1 increased while phosphorylation of Akt and ERK1 decreased as functions of tumor volume. Cell proliferation, evaluated from Ki-67 and phospho-histone H3 staining, was ~60% lower in breast cancer of NBCn1 KO than that of WT mice when corrected for variations in tumor size. We conclude that NBCn1 facilitates acid extrusion from breast cancer tissue, maintains the alkaline intracellular environment and promotes aggressive cancer development and growth.Oncogene advance online publication, 27 July 2015; doi:10.1038/onc.2015.273. © 2015 Macmillan Publishers Limited
Nielsen L.,University of Aarhus
Medicine, Health Care and Philosophy | Year: 2013
In recent works, Shlomi Segall suggests and defends a luck egalitarian approach to justice in health. Concurring with G. A. Cohen's mature position he defends the idea that people should be compensated for "brute luck", i.e. the outcome of actions that it would be unreasonable to expect them to avoid. In his defense of the luck egalitarian approach he seeks to rebut the criticism raised by Norman Daniels that luck egalitarianism is in some way too narrow and in another too wide to uphold justice in health and health care distribution. He points out that a pluralistic outline of luck egalitarianism taking into account the moral requirement of meeting everyone's basic needs can avoid this line of criticism. In this article I argue against the application of such pluralistic luck egalitarianism in matters of health distribution. First of all, Segall has not shown that luck egalitarianism handles well health distributions above a threshold of basic needs. Secondly, his way of avoiding Elizabeth Anderson's abandonment objection is theoretically problematic. Finally, I argue that luck egalitarianism in general fails to acknowledge the moral foundation of health and health care as a basic human entitlement. Thus I conclude that luck egalitarianism fails to take health needs seriously and that it cannot therefore uphold justice in health. © 2012 Springer Science+Business Media B.V.
Otzen D.E.,University of Aarhus
Structure | Year: 2011
Taylor et al. report the crystal structure of CsgC, a redox-active member of E. coli's curli-producing Csg operon. The outer membrane protein CsgG is a potential redox-substrate and might exist in an octameric structure with a periplasmatic CsgC binding site, highlighting a potential role for disulfide bonds in curli production. © 2011 Elsevier Ltd.
Petersen S.O.,University of Aarhus
Animal : an international journal of animal bioscience | Year: 2013
Ongoing intensification and specialisation of livestock production lead to increasing volumes of manure to be managed, which are a source of the greenhouse gases (GHGs) methane (CH4) and nitrous oxide (N2O). Net emissions of CH4 and N2O result from a multitude of microbial activities in the manure environment. Their relative importance depends not only on manure composition and local management practices with respect to treatment, storage and field application, but also on ambient climatic conditions. The diversity of livestock production systems, and their associated manure management, is discussed on the basis of four regional cases (Sub-Saharan Africa, Southeast Asia, China and Europe) with increasing levels of intensification and priorities with respect to nutrient management and environmental regulation. GHG mitigation options for production systems based on solid and liquid manure management are then presented, and potentials for positive and negative interactions between pollutants, and between management practices, are discussed. The diversity of manure properties and environmental conditions necessitate a modelling approach for improving estimates of GHG emissions, and for predicting effects of management changes for GHG mitigation, and requirements for such a model are discussed. Finally, we briefly discuss drivers for, and barriers against, introduction of GHG mitigation measures for livestock production. There is no conflict between efforts to improve food and feed production, and efforts to reduce GHG emissions from manure management. Growth in livestock populations are projected to occur mainly in intensive production systems where, for this and other reasons, the largest potentials for GHG mitigation may be found.
Andresen K.J.,University of Aarhus |
Huuse M.,University of Manchester
Marine Geology | Year: 2011
This study describes a new type of pockmark association from the Lower Congo Basin offshore West Africa, consisting of up to 8 stacked paleopockmarks separated by intervals of drape and onlap fill. The stacked paleopockmarks occur within the depocentres of polygonally-faulted Plio-Pleistocene sediments and are distributed evenly in the downslope parts of two salt mini-basins. The majority of the stacked pockmarks initiated synchronously in the late Pliocene (~. 3. Ma) with a subordinate initiation phase in the mid Pliocene (~. 4. Ma). The primary agents in pockmark formation are interpreted to be pore water expelled during early-stage compaction together with biogenic methane. Bottom simulating reflections (BSRs) associated with free gas overlain by gas hydrates are currently found in the area. It is speculated that biogenic methane accumulated within and below a clathrate cap, which was repeatedly breached, forming pockmarks at discrete horizons separated by intervals of draping sedimentation. The mid and late Pliocene pockmark initiations appear to coincide with sea-level falls following periods of relatively stable highstand conditions. Several subsequent pockmark horizons may similarly correlate with subsequent sea-level falls during the late Pliocene and early Pleistocene. The stacked paleopockmarks are completely surrounded by polygonal faults and consistently occur within polygonal fault cells that crosscut the succession containing the stacked pockmarks. Early-stage compaction and dewatering of the Pliocene sediments thus preceded polygonal faulting, providing a constraint on the conditions leading to polygonal faulting of the fine-grained host sediments. The relationship documented here is interpreted as due to the presence of a hydrate cap in the Plio-Pleistocene mini-basins which may have retarded the normal compaction processes and facilitated pockmark formation by allowing the build up of gas hydrate and free gas in the basin centres. The relative timing and spatial relationships implies that fluids expelled due to polygonal faulting were not implicated in pockmark formation in this area. © 2010 Elsevier B.V.
Riber A.B.,University of Aarhus
Poultry Science | Year: 2015
Broiler houses are mainly lit by fluorescent light. With the expected continued increase in energy prices, the interest in less energy consuming light sources is growing. The light-emitting diode (LED) is an energy-saving alternative. The aims of the present 2 studies were to examine 1) the preference for LED color temperature and effects on behavior, and 2) effects of LED color temperature on performance and welfare of male broilers (Ross 308). Two color temperatures were investigated: neutral-white (4,100∈K) and cold-white (6,065∈K). First, 6 groups of 6-day-old chicks were housed in pens consisting of 2 lightproof compartments with a pop-hole between allowing chicks to move freely between compartments. Number of broilers in each compartment and their behavior were recorded every 15 min on 6 d. A preference for 6,065∈K was found (P < 0.001). On d 16, 28, and 34, more time was spent in the 6,065∈K treatment (P < 0.03), whereas indifference between treatments was found on d 4, 10, and 22 (P > 0.07). Second, each of the 2 light conditions was applied to 6 groups of 75 chicks. BW and feed consumption were registered weekly. On d 34, we scored gait, foot pad dermatitis, and hock burns in 15 individuals/pen. At slaughter (d 35), cold carcass weight was recorded from all individuals, while yields of different body parts were collected from 9 individuals/group. Broilers from the 6,065∈K treatment were 67.4 ± 19.2 g heavier on the day of slaughter (P = 0.0009), whereas no difference was found at other ages (P > 0.12). Feed intake was found to be similar for the 2 treatments (P = 0.52). Pectoralis minor was 4.1 ± 1.9 g heavier in the 6,065∈K treatment (P = 0.03). There was no difference between the light treatments in any of the welfare parameters. We conclude from the results that of the 2 color temperatures examined, the most suitable for use in commercial broiler houses is 6,065∈K. © 2015 Poultry Science Association Inc.
Obermann M.-L.,University of Aarhus
Journal of School Violence | Year: 2011
This study examined the use of moral disengagement among children indirectly involved in bullying (bystanders). A sample of Danish adolescents (N = 660, M age 12.6 years) were divided into four groups depending on their bystander status: (a) outsiders, who did not experience bullying among their peers; (b) defenders, who were likely to help the victims in bullying episodes; (c) guilty bystanders, who did nothing to help bullied peers but felt guilty about it; and (d) unconcerned bystanders, who witnessed peers being bullied, without feeling responsible. Results indicated that, besides from active personal involvement in bullying others, being an unconcerned bystander to bullying also associates with moral disengagement. Unconcerned bystanders had significantly higher moral disengagement than guilty bystanders and defenders. Outsiders also showed significant higher disengagement than defenders. Implications are discussed, highlighting the importance of further research and theory development. © Taylor & Francis Group, LLC.
Christensen T.,University of Aarhus
Journal of Neuroimmune Pharmacology | Year: 2010
In humans, exogenous retroviruses are known to cause immunodeficiency and neurological disease. While endogenous retroviruses are firmly established pathogens in other species, the human endogenous retroviruses (HERVs) may well be considered as emerging pathogens. HERVs also exhibit complex interactions with exogenous retroviruses and herpesviruses. Two neurological disorders in particular are associated with HERVs: multiple sclerosis (MS) and schizophrenia. HERV-H/F and HERV-W are specifically activated both in the circulation and the central nervous system (CNS) in a majority of MS patients, and particularly, the envelopes (env transcription and Env proteins) appear strongly associated with disease activity. Interferon beta (IFN-β) therapy is well-established for MS. IFN-β is also known to have anti-retroviral activities toward exogenous retroviruses (HIV and HTLV-I). New reports show that IFN-β also mediate down-regulation of HERV-H/F and HERV-W in MS patients. HERV-W and HERV-K transcription (gag and pol) appears, to some extent, to be up-regulated in the circulation and the CNS of patients with schizophrenia. The expression of anti-HERV-W Gag reactive epitopes is reported to be down-regulated in the brain but up-regulated in the blood from schizophrenia patients. The pathogenic potential of HERVs certainly merits further studies. © 2010 Springer Science+Business Media, LLC.
Liu C.-J.,Tianjin University |
Burghaus U.,North Dakota State University |
Besenbacher F.,University of Aarhus |
Wang Z.L.,Georgia Institute of Technology
ACS Nano | Year: 2010
The use of nanotechnology to develop a suite of sustainable energy production schemes is one of the most important scientific challenges of the 21st century. The challenge is to design, to synthesize, and to characterize new functional nanomaterials with controllable sizes, shapes, and/or structures. To summarize the progress of the research and development made in this important field, the Fuel Chemistry Division of the American Chemical Society (ACS) organized a symposium on "Nanotechnology for Sustainable Energy and Fuels" during the 240th ACS National Meeting in Boston, MA on August 22-26, 2010, with the ACS Catalysis Division as the cosponsor. This symposium was a global gathering of leading scientists at the intersection of energy and nanotechnology. The topics discussed at the symposium included nanotechnology, not only for traditional fossil fuel production but also for novel processes for renewable energy applications. This article aims to highlight some of the most exciting advances presented at the symposium, including the preparation and characterization of nanomaterials for clean fuel production, CO2 capture, solar cells and solar fuels, energy conversion and storage materials, hydrogen storage materials, and fuel cells. Finally, possible future developments in this important and timely area are discussed. © 2010 American Chemical Society.
Rattan S.I.S.,University of Aarhus
Biogerontology | Year: 2013
Ageing occurs in spite of complex pathways of maintenance and repair. There is no "enemy within", which has the specific evolution-selected function to cause ageing and death. This understanding of ageing should transform our approach towards interventions from therapeutic "anti-ageing" to maintaining health. But what is health? Ideally, health is a state of complete physical and mental independence in activities of daily living. But in pragmatic terms, health is a state of adequate physical and mental independence in activities of daily living. In order to identify a set of measurable, evidence-based and demonstratable parameters of health, robustness and resilience at various levels, the concept of homeodynamic space can be a useful one. Age-related health problems for which there are no clear-cut causative agents, except the complex process of ageing, may be better tackled by focusing on health mechanisms and their maintenance, rather than disease management and treatment. Continuing the disease-oriented research approaches are economically, socially and psychologically unsustainable as compared with health-oriented and preventive strategies, such as hormesis. Supporting health-oriented research is the urgency of our time. © 2013 Springer Science+Business Media Dordrecht.
Poulsen T.B.,University of Aarhus
Chemical Communications | Year: 2011
An efficient synthesis of the macrolactone core of the rakicidins is described. The rakicidins are cytotoxic lipopeptides with interesting cancer cell selectivities including HIF-1-independent hypoxia-selective cytotoxicity and anti-invasive activity. Access to the core may now allow establishment of preliminary SAR and exploration of routes to several members of rakicidins. © 2011 The Royal Society of Chemistry.
Lovendahl P.,University of Aarhus |
Chagunda M.G.G.,Sustainable Livestock Systems Group
Journal of Dairy Science | Year: 2010
Detection of estrus in dairy cattle is effectively aided by electronic activity tags or pedometers. Characterization of estrus intensity and duration is also possible from activity data. This study aimed to develop an algorithm to detect and characterize behavioral estrus from hourly recorded activity data and to apply the algorithm to activity data from an experimental herd. The herd comprised of Holstein (n=211), Jersey (n=126), and Red Dane (n=178) cattle, with virgin heifers (n=132) and lactating cows in the first 4 parities; n=895 cow-parities, with a total of 3,674 activity episodes. The algorithm was based on deviations from exponentially smoothed hourly activity counts and was used to identify onset, duration, and intensity of estrus. Learning data included 461 successful inseminations with activity records over a 2-wk period before and after the artificial insemination. Rates of estrus detection and error rate depended on the chosen threshold level. At a threshold giving 74.6% detection rate, daily error rate was 1.3%. When applied to a subset of the complete data where milk progesterone was also available, concordance of days to first activity-detected estrus with the similar trait based on progesterone was also dependent on the chosen threshold so that, with stricter thresholds, the agreement was closer. A single-trait mixed model was used to determine the effects of systematic factors on the estrus activity traits. In general, an activity episode lasted 9.24. h in heifers and 8.12. h in cows, with the average strength of 1.03 ln units (equivalent to a 2.8-fold increase) in both age groups. Red Danes had significantly fewer days to first episode of high activity than Holsteins and Jerseys (29.4, 33.1, and 33.9 d, respectively). However, Jerseys had significantly shorter duration and less strength of estrus than both Red Danes and Holsteins of comparable age. The random effect of cow affected days to first episode of high activity and strength as well as estrus duration. Days from calving to first episode of high activity correlated negatively with body condition scores in early lactation. The results suggest that data from activity monitors could supply valuable information about fertility traits and could thereby be helpful in management of herd fertility. To establish the complementarities or interdependence between progesterone and activity measurements, further studies with more information from different sources of measuring estrus are needed. © 2010 American Dairy Science Association.
Aharon N.,Tel Aviv University |
Drewsen M.,University of Aarhus |
Retzker A.,Hebrew University of Jerusalem
Physical Review Letters | Year: 2013
We present a new robust decoupling scheme suitable for levels with either half-integer or integer angular momentum states. Through continuous dynamical decoupling techniques, we create a protected qubit subspace, utilizing a multistate qubit construction. Remarkably, the multistate system can also be composed of multiple substates within a single level. Our scheme can be realized with state-of-the-art experimental setups and thus has immediate applications for quantum information science. While the scheme is general and relevant for a multitude of solid-state and atomic systems, we analyze its performance for the case composed of trapped ions. Explicitly, we show how single qubit gates and an ensemble coupling to a cavity mode can be implemented efficiently. The scheme predicts a coherence time of ∼1 s, as compared to typically a few milliseconds for the bare states. © 2013 American Physical Society.
Walter A.,ETH Zurich |
Studer B.,University of Aarhus |
Kolliker R.,ART Agroscope Reckenholz Tanikon
Annals of Botany | Year: 2012
Background and AimsAdvanced phenotyping, i.e. the application of automated, high-throughput methods to characterize plant architecture and performance, has the potential to accelerate breeding progress but is far from being routinely used in current breeding approaches. In forage and turf improvement programmes, in particular, where breeding populations and cultivars are characterized by high genetic diversity and substantial genotype × environment interactions, precise and efficient phenotyping is essential to meet future challenges imposed by climate change, growing demand and declining resources.ScopeThis review highlights recent achievements in the establishment of phenotyping tools and platforms. Some of these tools have originally been established in remote sensing, some in precision agriculture, while others are laboratory-based imaging procedures. They quantify plant colour, spectral reflection, chlorophyll-fluorescence, temperature and other properties, from which traits such as biomass, architecture, photosynthetic efficiency, stomatal aperture or stress resistance can be derived. Applications of these methods in the context of forage and turf breeding are discussed.ConclusionsProgress in cutting-edge molecular breeding tools is beginning to be matched by progress in automated non-destructive imaging methods. Joint application of precise phenotyping machinery and molecular tools in optimized breeding schemes will improve forage and turf breeding in the near future and will thereby contribute to amended performance of managed grassland agroecosystems. © 2012 The Author 2012. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissionsoup.com.
Vorup-Jensen T.,University of Aarhus
Methods in Molecular Biology | Year: 2011
Measurements on the kinetic aspects of binding between macromolecular species such as proteins have been greatly advanced by the application of surface plasmon resonance (SPR) biosensors. In studies of ligand binding by integrin I domains, technologies such as the BIAcore instruments have provided important insights into the role of conformational regulation. This chapter describes a protocol for studying the binding between the I domain from integrin α Xβ 2 and its ligand iC3b. Also included are topics on the interpretation of data. Integrin I domains appear to support heterogeneous interactions with ligands, which pose significant challenges in deriving valid information on the binding kinetics from the SPR measurements. Fortunately, new algorithms are available that may resolve even complex ligand-binding reactions; with the application to data on the binding between the α X I domain, a more consistent and unambiguous result is obtained compared to those obtained by classical approaches for analyzing SPR biosensor data. © 2011 Springer Science+Business Media, LLC.
Svane A.M.,University of Aarhus
Journal of Mathematical Imaging and Vision | Year: 2014
Local digital algorithms based on n×⋯×n configuration counts are commonly used within science for estimating intrinsic volumes from binary images. This paper investigates multigrid convergence of such algorithms. It is shown that local algorithms for intrinsic volumes other than volume are not multigrid convergent on the class of convex polytopes. In fact, counter examples are plenty. On the other hand, for convex particles in 2D with a lower bound on the interior angles, a multigrid convergent local algorithm for the Euler characteristic is constructed. Also on the class of r-regular sets, counter examples to multigrid convergence are constructed for the surface area and the integrated mean curvature. © 2013 Springer Science+Business Media New York.
Bendtsen J.,VitusLab. |
Hansen J.L.S.,University of Aarhus
Ecological Modelling | Year: 2013
Hypoxic conditions (O2<2mgL-1) are frequently observed in the relatively shallow and stratified North Sea-Baltic Sea transition zone. Inter-annual variability with more extensive hypoxia has been observed in years with calm weather conditions during late summer. A future warmer climate may increase hypoxia in the area due to combined effects from decreased oxygen solubility and increased respiration rates. Feedbacks from climate change can, therefore, amplify negative effects from eutrophication, such as hypoxia. Here we apply a high resolution three-dimensional ocean circulation model with a simple pelagic and benthic oxygen consumption model (OXYCON), based on the seasonal organic carbon budget in the area, and demonstrate that the model is able to simulate the temporal and spatial variability of the observed oxygen concentration in the bottom waters during a three-year period. The potential impact from a warmer climate was analysed in a sensitivity study with a 3°C warmer climate, and showed a significant increase of hypoxic bottom areas compared to present day conditions. The relative role of increased respiration and decreased oxygen solubility in the inflowing bottom water and at the surface was analysed and it was found that decreased solubility accounted for about 25% of the simulated decrease in bottom water oxygen concentration in the centre of the area in the early fall. A sensitivity study showed that the simulated effect from a 3°C temperature increase on the bottom water oxygen concentration could be compensated by a 30% reduction in the export production. The model simulations of the North Sea-Baltic Sea transition zone indicate a significant expansion of the hypoxic areas and a lengthening of the hypoxic period under a warmer climate. © 2012 Elsevier B.V.
Kragh H.,University of Aarhus
European Physical Journal H | Year: 2011
The atomic model introduced by Bohr in 1913 dominated the development of the old quantum theory. Its main features, such as the radiationless stationary states and the discontinuous quantum jumps between the states, were hard to swallow for contemporary physicists. While acknowledging the empirical power of the theory, many scientists criticized its foundation or looked for ways to reconcile it with classical physics. Among the chief critics were A. Crehore, J.J. Thomson, E. Gehrcke and J. Stark. This paper examines from a historical perspective the conceptual objections to Bohr's atom, in particular the stationary states (where electrodynamics was annulled by fiat) and the mysterious, apparently teleological quantum jumps. Although few of the critics played a constructive role in the development of the old quantum theory, a history neglecting their presence would be incomplete and distorted. © EDP Sciences, Springer-Verlag 2011.
Shimada A.,University of Aarhus
The journal of headache and pain | Year: 2013
A single intake of monosodium glutamate (MSG) may cause headache and increased muscle sensitivity. We conducted a double-blinded, placebo-controlled, crossover study to examine the effect of repeated MSG intake on spontaneous pain, mechanical sensitivity of masticatory muscles, side effects, and blood pressure. Fourteen healthy subjects participated in 5 daily sessions for one week of MSG intake (150 mg/kg) or placebo (24 mg/kg NaCl) (randomized, double-blinded). Spontaneous pain, pressure pain thresholds and tolerance levels for the masseter and temporalis muscles, side effects, and blood pressure were evaluated before and 15, 30, and 50 min after MSG intake. Whole saliva samples were taken before and 30 min after MSG intake to assess glutamate concentrations. Headache occurred in 8/14 subjects during MSG and 2/14 during placebo (P = 0.041). Salivary glutamate concentrations on Day 5 were elevated significantly (P < 0.05). Pressure pain thresholds in masseter muscle were reduced by MSG on Day 2 and 5 (P < 0.05). Blood pressure was significantly elevated after MSG (P < 0.040). In conclusion, MSG induced mechanical sensitization in masseter muscle and adverse effects such as headache and short-lasting blood pressure elevation for which tolerance did not develop over 5 days of MSG intake.
Comuth W.,University of Aarhus
Blood Coagulation and Fibrinolysis | Year: 2016
This is the report of a case of a 63-year-old woman, with a history of recurrent deep vein thrombosis, who was admitted with abdominal pain and diagnosed with bilateral adrenal hemorrhage, resulting in acute adrenal insufficiency. Several risk factors for adrenal hemorrhage were present: stress because of infection, treatment with the factor Xa-inhibitor rivaroxaban and the presence of antiphospholipid antibodies. Venous thrombosis of the adrenal glands with subsequent hemorrhagic infarction is a possible mechanism. It is currently unclear if patients with antiphospholipid syndrome can be treated effectively and safely with a nonvitamin K-antagonist oral anticoagulant. Copyright © 2016 YEAR Wolters Kluwer Health, Inc. All rights reserved.
Jarvinen M.,Copenhagen University |
Ravn S.,University of Aarhus
Sociology of Health and Illness | Year: 2011
This article analyses the process of going from recreational use to regular and problematic use of illegal drugs. We present a model containing six career contingencies relevant for young people's progress from recreational to regular drug use: the closing of social networks, changes in forms of parties, intoxication becoming a goal in itself, easier access to drugs, learning to recognise alternative effects of drugs and experiences of loss of control. The analysis shows that these dimensions are at play not only when young people develop a regular drug use pattern but also when they attempt to extricate themselves from this pattern. Hence, when regular drug users talk about their future, it is not a future characterised by total abstinence from illegal drugs but a future where they have rolled back their drug use career to the recreational drug use pattern they started out with. Empirically, the article is based on qualitative interviews with young drug users contacted at nightclubs in Denmark © 2011 The Authors. Sociology of Health & Illness © 2011 Foundation for the Sociology of Health & Illness/Blackwell Publishing Ltd.
Tolstikhin O.I.,Moscow Institute of Physics and Technology |
Madsen L.B.,University of Aarhus |
Morishita T.,University of Electro - Communications
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014
The weak-field asymptotic theory of tunneling ionization in an external static uniform electric field [Tolstikhin et al., Phys. Rev. A 84, 053423 (2011)PLRAAN1050-294710.1103/PhysRevA.84.053423] is extended to many-electron atomic and molecular systems treated in the frozen-nuclei approximation. The leading-order term in the asymptotic expansion of the ionization rate Γ in the value of the field F for F→0 is obtained. The resulting formulas express Γ in terms of properties of the unperturbed system. The most essential difference from the one-electron case, through which the many-electron character of the present theory reveals itself, is that the structure factor for a given ionization channel, defining the dependence of the ionization rate into this channel on the orientation of the system with respect to the field, is determined by the corresponding Dyson orbital. The theory is illustrated by calculations for several few-electron systems. The asymptotic results are compared with accurate fully correlated calculations of tunneling ionization rates available in the literature. © 2014 American Physical Society.
Vosegaard T.,University of Aarhus
Magnetic Resonance in Chemistry | Year: 2015
Toyoshima C.,University of Tokyo |
Kanai R.,University of Tokyo |
Cornelius F.,University of Aarhus
Structure | Year: 2011
Na +,K +-adenosine triphosphatase (NKA) is the first P-type ion translocating adenosine triphosphatase (ATPase) ever identified, and the significance of this class of proteins was highlighted by the 1997 Nobel Prize in Chemistry awarded to Jens C. Skou for the discovery in 1957. More than half a century passed between the initial identification and the publication of a high-resolution crystal structure of NKA. Although the new crystal structures provided many surprises and insights, structural biology on this system remains challenging, as NKA is a very difficult protein to crystallize. Here we explain the reasons behind the challenges, introduce a mechanism that governs the function, and summarize current knowledge of NKA structure in comparison with another member of the P-type ATPase family, Ca 2+-ATPase. © 2011 Elsevier Ltd All rights reserved.
Petrosyan D.,Institute of Electronic Structure and Laser |
Molmer K.,University of Aarhus
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013
We study two-photon excitation of Rydberg states of atoms under stimulated adiabatic passage with delayed laser pulses. We find that the combination of strong interaction between the atoms in Rydberg state and the spontaneous decay of the intermediate exited atomic state leads to the Rydberg excitation of precisely one atom within the atomic ensemble. The quantum Zeno effect offers a lucid interpretation of this result: the Rydberg blocked atoms repetitively scattering photons effectively monitor a randomly excited atom, which therefore remains in the Rydberg state. This system can be used for deterministic creation and, possibly, extraction of Rydberg atoms or ions one at a time. The sympathetic monitoring via decay of ancilla particles may find wider applications for state preparation and probing of interactions in dissipative many-body systems. © 2013 American Physical Society.
Sorensen L.K.,University of Aarhus
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2011
A liquid-chromatography-tandem-mass-spectrometry method using pneumatically assisted electrospray ionisation (LC-ESI-MS/MS) was developed for the simultaneous determination of cathinone, methcathinone, ethcathinone, amfepramone, mephedrone, flephedrone, methedrone, methylone, butylone, cathine, norephedrine, ephedrine, pseudoephedrine, methylephedrine and methylpseudoephedrine in human live and post-mortem whole blood. The blood proteins were precipitated by the addition of methanol, and the extract was purified by ultrafiltration. The separation of diastereomeric ephedrines was achieved on an ethyl-linked phenyl column. Matrix-matched calibrants combined with the isotope dilution of selected substances were used for quantitative analysis. The relative intra-laboratory reproducibility standard deviations were generally better than 7% at concentrations of 20. μg/L, and the mean true recoveries were 87-106% in the concentration range of 10-250. μg/L. The detection limits were in the range of 0.5-3. μg/L. The cathinones were unstable in whole blood and sample extracts under neutral conditions, but the stability could be improved by the acidification of the sample matrix. © 2011 Elsevier B.V.
McCloy K.R.,University of Aarhus
Remote Sensing | Year: 2010
Changes in vegetation phenology are recognized as being possibly the most important early indicator of the impact of climate change on ecosystems. Time series of image data are accepted as being the best way to map these changes, if we can derive suitable indices from the huge volumes of time series data that make the interpretation of these time series difficult. The problem is thus to derive a set of indices from the time series of image data that depict changes in vegetation phenology in a way that is easy to analyze and use. This problem has been solved by deriving a set of six Phenological Change Indices that measure the five ways that the phenological curve of vegetation can change over time. These indices were then tested using simulated data based on sample phenological profiles for a set of land covers and showed that four of the indices measured four of the ways that the phenological profile can change, and two of the indices gave similar results in measuring the last way that the phenological profiles can change. A time series of image data was then used to map the Phenological Change Indices for Eurasia and a sample of land covers was used to relate the changes in phenology to location for each land cover. This work showed that the detected changes in phenology are similar to those found in other papers. The benefit of these indices is that we can now analyze changes in phenology in a much more detailed and accurate way than has been possible until now. © 2010 by the authors.
Wang T.,University of Aarhus
Acta physiologica (Oxford, England) | Year: 2011
The mechanisms governing pulmonary gas exchange were heavily debated at the start of the 20th century when Christian Bohr provided measurements of lung and blood gases as well as rational arguments in favour of oxygen being secreted actively from the lung gas to the blood within vertebrate lungs. The concept of active transport was studied by August Krogh in his doctoral dissertation on the partitioning of gas exchange in frogs. In later studies, where Marie and August Krogh provided conclusive evidence that pulmonary gas exchange occurs by diffusion and diffusion alone, the turtle lungs provided an important tool to investigate the role of perfusion in pulmonary gas exchange. Here, I review the early Bohr and Krogh studies on pulmonary and cutaneous gas exchange in frogs as well as the experimental studies on gas exchange and its possible autonomic regulation in turtles. The results are discussed within the context of recent studies on the cardiorespiratory physiology of frogs and turtles. © 2011 The Author. Acta Physiologica © 2011 Scandinavian Physiological Society.
Nielsen L.P.,University of Aarhus
Current Biology | Year: 2016
Animals at the bottom of the sea survive oxygen depletion surprisingly often, and a new study identifies cable bacteria in the sediment as the saviors. The bacterial electrical activity creates an iron 'carpet', trapping toxic hydrogen sulfide. © 2016 Elsevier Ltd.
Otzen D.,University of Aarhus
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2011
The scientific study of protein surfactant interactions goes back more than a century, and has been put to practical uses in everything from the estimation of protein molecular weights to efficient washing powder enzymes and products for personal hygiene. After a burst of activity in the late 1960s and early 1970s that established the general principles of how charged surfactants bind to and denature proteins, the field has kept a relatively low profile until the last decade. Within this period there has been a maturation of techniques for more accurate and sophisticated analyses of protein-surfactant complexes such as calorimetry and small angle scattering techniques. In this review I provide an overview of different useful approaches to study these complexes and identify eight different issues which define central concepts in the field. (1) Are proteins denatured by monomeric surfactant molecules, micelles or both? (2) How does unfolding of proteins in surfactant compare with "proper" unfolding in chemical denaturants? Recent work has highlighted the role of shared micelles, rather than monomers, below the critical micelle concentration (cmc) in promoting both protein denaturation and formation of higher order structures. Kinetic studies have extended the experimentally accessible range of surfactant concentrations to far above the cmc, revealing numerous different modes of denaturation by ionic surfactants below and above the cmc which reflect micellar properties as much as protein unfolding pathways. Uncharged surfactants follow a completely different denaturation strategy involving synergy between monomers and micelles. The high affinity of charged surfactants for proteins means that unfolding pathways are generally different in surfactants versus chemical denaturants, although there are common traits. Other issues are as follows: (3) Are there non-denaturing roles for SDS? (4) How reversible is unfolding in SDS? (5) How do solvent conditions affect the way in which surfactants denature proteins? The last three issues compare SDS with "proper" membranes. (6) Do anionic surfactants such as SDS mimic biological membranes? (7) How do mixed micelles interact with globular proteins? (8) How can mixed micelles be used to measure the stability of membrane proteins? The growing efforts to understand the unique features of membrane proteins have encouraged the development of mixed micelles to study the equilibria and kinetics of this class of proteins, and traits which unite globular and membrane proteins have also emerged. These issues emphasise the amazing power of surfactants to both extend the protein conformational landscape and at the same time provide convenient and reversible short-cuts between the native and denatured state for otherwise obdurate membrane proteins. © 2011 Elsevier B.V. All Rights Reserved.
Tegner C.,University of Aarhus |
Cawthorn R.G.,University of Witwatersrand
Contributions to Mineralogy and Petrology | Year: 2010
The evolved, iron-rich rocks of the tholeiitic Bushveld and Skaergaard intrusions are similar in containing cumulus magnetite, ilmenite, plagioclase, clinopyroxene, apatite and olivine, and also orthopyroxenes/pigeonite in Bushveld. Here, we evaluate their liquid evolution trends using the total iron content in plagioclase determined by electron microprobe analyses. To aid this analysis a revised mass balance model for the liquid evolution of Skaergaard is presented. For plagioclase in the Upper Zone of Skaergaard it was previously demonstrated that total FeO increases from ~0.25 to ~0.45 wt% with differentiation and correlates inversely with An% [100 × Ca/(Na + Ca)]. The reverse trend is observed in two recently published datasets for Bushveld, showing that total FeO in plagioclase decreases upward through the magnetite-bearing Upper Zone from ~0.30 to ~0.15% and from ~0.40 to ~0.25% in the western and northern limbs, respectively, and correlates positively with An%. The partition coefficient of total iron between plagioclase and magma increases with oxidation and polymerisation in the liquid. Although Bushveld formed under slightly more oxidizing conditions than Skaergaard, differences in the partition coefficients cannot explain the two observed trends. We therefore conclude that the differentiation trends of the liquids subsequent to magnetite saturation were fundamentally different. The inferred liquid composition for Bushveld contained about 15 wt% total FeO at the level of magnetite-in, which is slightly less than the total FeO content of the subsequent cumulates. In contrast, the Skaergaard liquid contained more total FeO than the ensuing cumulates. As a result, in Bushveld residual liquids total FeO decreased after magnetite saturation, whereas in Skaergaard the residual liquids continued to become enriched in iron. This conclusion is corroborated by simple mass balance calculations between modelled residual liquids and extracted cumulate rocks. Despite the mineralogical similarities of evolved iron-rich rocks of Skaergaard and Bushveld, their liquid evolution trends were very different, and generalizations about the extent of iron enrichment in tholeiitic magmas should be avoided. © 2009 Springer-Verlag.
Weber R.E.,University of Aarhus |
Campbell K.L.,University of Manitoba
Acta Physiologica | Year: 2011
As demonstrated by August Krogh et al. a century ago, the oxygen-binding reaction of vertebrate haemoglobin is cooperative (described by sigmoid O2 equilibrium curves) and modulated by CO2 and protons (lowered pH) that - in conjunction with later discovered allosteric effectors (chloride, lactate and organic phosphate anions) - enhance O2 unloading from blood in relatively acidic and oxygen-poor tissues. Based on the exothermic nature of the oxygenation of the haem groups, haemoglobin-O2 affinity also decreases with rising temperature. This thermal sensitivity favours oxygen unloading in warm working muscles, but may become detrimental in regionally heterothermic animals, for example in cold-tolerant birds and mammals and warmbodied fish, where it may perturb the balance between O2 unloading and O2 requirement in organs with substantially different temperatures than at the respiratory organs and thus commonly is reduced or obliterated. Given that the oxygenation of haemoglobin is linked with the endothermic release of allosteric effectors, increased effector interaction is an effective strategy that is widely exploited to achieve adaptive reductions in the temperature dependence of blood-O2 affinity. The molecular mechanisms implicated in heterothermic vertebrates from different taxonomic groups reveal remarkable variability, both as regards the effectors implicated (protons in tunas, organic phosphates in sharks and billfish, chloride ions in ruminants and chloride and phosphate anions in the extinct woolly mammoth, etc.) and binding sites for the same effectors, indicating multiple evolutionary origins, but convergent physiological functionality (reductions in temperature dependence of O2-binding affinity that safeguard tissue O2 supply). © 2010 The Authors.
Riisager K.,University of Aarhus
Physica Scripta | Year: 2013
The halo structure originated from nuclear physics but is now encountered more widely. It appears in loosely bound, clustered systems where the spatial extension of the system is significantly larger than that of the binding potentials. A review is given on our current understanding of these structures, with an emphasis on how the structures evolve as more cluster components are added and on the experimental situation concerning halo states in light nuclei. © 2013 The Royal Swedish Academy of Sciences.
Ogilby P.R.,University of Aarhus
Photochemical and Photobiological Sciences | Year: 2010
Singlet oxygen, O2(a1Δg), the lowest excited electronic state of molecular oxygen, has a characteristic chemistry that sets it apart from the triplet ground state of oxygen, O2(X 3Σ-g). Although singlet oxygen can be produced in a variety of ways, it is arguably best known as a product of the interaction between a light absorbing chromophore (i.e., a photosensitizer) and O2(X 3Σ-g). In this way, it plays a key role in the many disciplines that comprise the "photosciences". As outlined in this Perspective, which is part of the program "Photosciences: a look to the future", the study of singlet oxygen provides a coalescence point for many topics currently at the cutting edge of modern science ranging from materials science to biology and medicine. As such, although singlet oxygen is a "mature citizen" and has been examined for many years in a variety of contexts, there is still something new under the sun, and the future looks exceedingly bright for this photo-related discipline. © 2010 The Royal Society of Chemistry and Owner Societies.
Stranden I.,Mtt Agrifood Research Finland |
Christensen O.F.,University of Aarhus
Genetics Selection Evolution | Year: 2011
Background: Genomic data are used in animal breeding to assist genetic evaluation. Several models to estimate genomic breeding values have been studied. In general, two approaches have been used. One approach estimates the marker effects first and then, genomic breeding values are obtained by summing marker effects. In the second approach, genomic breeding values are estimated directly using an equivalent model with a genomic relationship matrix. Allele coding is the method chosen to assign values to the regression coefficients in the statistical model. A common allele coding is zero for the homozygous genotype of the first allele, one for the heterozygote, and two for the homozygous genotype for the other allele. Another common allele coding changes these regression coefficients by subtracting a value from each marker such that the mean of regression coefficients is zero within each marker. We call this centered allele coding. This study considered effects of different allele coding methods on inference. Both marker-based and equivalent models were considered, and restricted maximum likelihood and Bayesian methods were used in inference. Results: Theoretical derivations showed that parameter estimates and estimated marker effects in marker-based models are the same irrespective of the allele coding, provided that the model has a fixed general mean. For the equivalent models, the same results hold, even though different allele coding methods lead to different genomic relationship matrices. Calculated genomic breeding values are independent of allele coding when the estimate of the general mean is included into the values. Reliabilities of estimated genomic breeding values calculated using elements of the inverse of the coefficient matrix depend on the allele coding because different allele coding methods imply different models. Finally, allele coding affects the mixing of Markov chain Monte Carlo algorithms, with the centered coding being the best. Conclusions: Different allele coding methods lead to the same inference in the marker-based and equivalent models when a fixed general mean is included in the model. However, reliabilities of genomic breeding values are affected by the allele coding method used. The centered coding has some numerical advantages when Markov chain Monte Carlo methods are used. © 2011 Strandén and Christensen; licensee BioMed Central Ltd.
Freer M.,University of Birmingham |
Fynbo H.O.U.,University of Aarhus
Progress in Particle and Nuclear Physics | Year: 2014
The 7.65 MeV, Jπ=0+, second excited state in 12C is known as the Hoyle-state after Fred Hoyle. In the 1950s Hoyle proposed the existence of the state in order to account for the stellar abundance of carbon. Aside from its key role in the synthesis of the elements it is believed to possess a rather unusual structure, where the dominant degrees of freedom are those of α-particle clusters rather than nucleons. An understanding of the properties of the Hoyle state, for example its radius and excitations, has been the focus of a major experimental activity. Similarly, unravelling precisely why a cluster state should arise at precisely the right energy to promote synthesis of carbon has been a central theoretical challenge. To a significant extent, the Hoyle-state has become a cornerstone for state-of-the-art nuclear theory. This review examines the present status of both theory and experiment and indicates directions for future developments to resolve some of the remaining open questions. © 2014 Published by Elsevier B.V. All rights reserved.
Hee L.,University of Aarhus
Acta Obstetricia et Gynecologica Scandinavica | Year: 2014
Objective To give an overview of the methods available for biomechanical testing of the non-pregnant and pregnant uterine cervix in vivo.Methods The following databases were searched. PubMed, Embase, and Cochrane Library. Additional studies were identified from reference lists. Only studies on in vivo biomechanical testing on both pregnant and non-pregnant women were included.Main outcome measures Estimation of distensibility, compressibility, and biochemical composition of the uterine cervix.Results The distensibility methods evaluated a physiologic variable and might serve as a gold standard; however, they may never be clinically useful as they involve instrumentation of the cervical canal. The compression methods evaluated an unphysiological variable but despite that, they seemed to evaluate biologically relevant figures and were non-invasive. Of the methods evaluating the biomechanical properties indirectly, those based on ultrasound may be clinically useful. Other indirect methods only measured variables within the most superficial layer of the distal uterine cervix, so further studies are needed to evaluate whether these measurements reflect the entire organ. Both compression methods and indirect methods were similar or superior to the Bishop score and to cervical length measurements regarding prediction of spontaneous preterm delivery and successful induction of labor in small studies.Conclusion The methods may have the potential to detect the biomechanical changes in the uterine cervix before the cervical length has shortened. The most promising methods need large-scale clinical testing regarding induction of labor and preterm delivery before they can be used in the clinic. © 2014 Nordic Federation of Societies of Obstetrics and Gynecology.
De Montjoye Y.-A.,Massachusetts Institute of Technology |
Radaelli L.,University of Aarhus |
Singh V.K.,Massachusetts Institute of Technology |
Singh V.K.,Rutgers University |
Pentland A.S.,Massachusetts Institute of Technology
Science | Year: 2015
Large-scale data sets of human behavior have the potential to fundamentally transform the way we fight diseases, design cities, or perform research. Metadata, however, contain sensitive information. Understanding the privacy of these data sets is key to their broad use and, ultimately, their impact.We study 3 months of credit card records for 1.1 million people and show that four spatiotemporal points are enough to uniquely reidentify 90% of individuals.We show that knowing the price of a transaction increases the risk of reidentification by 22%, on average. Finally, we show that even data sets that provide coarse information at any or all of the dimensions provide little anonymity and that women are more reidentifiable than men in credit card metadata.
Albertsen A.,University of Aarhus
Journal of Medicine and Philosophy (United Kingdom) | Year: 2015
Luck egalitarianism is often taken to task for its alleged harsh implications. For example, it may seem to imply a policy of non-assistance toward uninsured reckless drivers who suffer injuries. Luck egalitarians respond to such objections partly by pointing to a number of factors pertaining to the cases being debated, which suggests that their stance is less inattentive to the plight of the victims than it might seem at first. However, the strategy leaves some cases in which the attribution of individual responsibility is appropriate (and so, it seems, is asking people to pick up the tab for their choices). One such case is oral health or significant aspects of this. It is appropriate, the paper argues, to hold people responsible for a number of factors that affect their oral health. A luck egalitarian approach inspired by John Roemer can assess whether people have acted responsibly by comparing their choices to those of their peers. A luck egalitarian approach to oral health would recommend prioritizing scarce resources in a responsibility-weighted queuing system and include copayment and general taxation among its measures of financing. © The Author 2015. Published by Oxford University Press, on behalf of the Journal of Medicine and Philosophy Inc. All rights reserved.
Thogersen J.,University of Aarhus
Journal of Macromarketing | Year: 2010
In a sustainability perspective, consumption research has an unfortunate individualizing bias, which means that macro and structural causes of unsustainable consumption tend to be ignored. Hence, a comprehensive model of determinants of the sustainability of consumption is developed and applied on a specific case: organic food consumption. The analyzed data are published research on why consumer purchase of organic food products differs between countries. As expected, organic food's share of total food consumption depends heavily on political regulation, including legal definitions and standards, financial support to farmers, and a national labeling system. Other important structural factors are soil conditions, an effective and efficient distribution system, and the size of the premium price demanded for organic food products. Macro factors such as the food culture and the culture's level of postmaterialism and environmental concern play an additional role. The evidence suggests that, together, macro and structural factors such as these are more, and probably considerably more, important for the sustainability of food consumption than are individual-level attitudinal variables. © The Author(s) 2010.
Heymann M.,University of Aarhus
Wiley Interdisciplinary Reviews: Climate Change | Year: 2010
Ideas and knowledge about climate have changed considerably in history. Ancient philosophers like Hippocrates and Aristotle shaped the understandings of climate, which remained very influential until well into the eighteenth century. The Scientific Revolution of the seventeenth century gave rise to new ways of systematic instrument-based observation of and increased public interest in weather and climate. These developments led to amechanistic understanding and a reductionist physical description of climate in the twentieth century, eventually in the form of a complex earth system. Furthermore, different understandings of climate coexisted in many periods of time. Only in the nineteenth and twentieth centuries specific scientific concepts of climate (a geographical understanding of climate in climatology until about the mid-twentieth century and a physical understanding of climate in climate science in the second half of the twentieth century) gained superior social credibility and cultural dominance. The understanding of climate involved more than the accumulation of scientific knowledge. It was rooted in social processes and cultural interests, which shaped different ideas of climate in different communities of actors and different historical times. © 2010 John Wiley & Sons, Ltd.
Kragh-Hansen U.,University of Aarhus
Biochimica et Biophysica Acta - General Subjects | Year: 2013
Background Human serum albumin and some of its ligand complexes possess enzymatic properties which are useful both in vivo and in vitro. Scope of review This review summarizes present knowledge about molecular aspects, practical applications and potentials of these properties. Major conclusions The most pronounced activities of the protein are different types of hydrolysis. Key examples are esterase-like activities involving Tyr411 or Lys199 and the thioesterase activity of Cys34. In the first case, hydrolysis involves water and both products are released, whereas in the latter cases one of the products is set free, and the other stays covalently bound to the protein. However, the modified Cys34 can be converted back to its reduced form by another compound/enzymatic system. Among the other activities are glucuronidase, phosphatase and amidase as well as isomerase and dehydration properties. The protein has great impact on the metabolism of, for example, eicosanoids and xenobiotics. Albumin with a metal ion-containing complex is capable of facilitating reactions involving reactive oxygen and nitrogen species. General significance Albumin is useful in detoxification reactions, for activating prodrugs, and for binding and activating drug conjugates. The protein can be used to construct smart nanotubes with enzymatic properties useful for biomedical applications. Binding of organic compounds with a metal ion often results in metalloenzymes or can be used for nanoparticle formation. Because any compound acting as cofactor and/or the protein can be modified, enzymes can be constructed which are not naturally found and therefore can increase, often stereospecifically, the number of catalytic reactions. This article is part of a Special Issue entitled Serum Albumin. © 2013 Elsevier B.V.
Amorim M.J.B.,University of Aveiro |
Scott-Fordsmand J.J.,University of Aarhus
Environmental Pollution | Year: 2012
Environmental effects of copper nanoparticles are little studied in terrestrial ecosystems. In the present article, the toxicity of copper nanoparticles (Cu-NP) on the enchytraeid Enchytraeus albidus is compared to the toxicity of a copper-salt (CuCl 2). The effect parameters studied were survival, reproductive output and avoidance behaviour. The results show that Cu-NP were more toxic to E. albidus than the same concentrations of the CuCl 2-salt. The physic-chemical analysis of the particles indicated that only a small fraction was released as ions. Hence, the results indicated a nanoparticle-specific effect - lower reproductive output and higher avoidance. This was observed as 2-8 fold (significant) lower ECx values for Cu-NP (EC 50-reprod = 95 mg Cu/kg; EC 50-avoid = 241 mg Cu/kg) exposed organisms compared to CuCl 2 (EC 50- reprod = 251 mg Cu/kg; EC 50-avoid = 475 mg Cu/kg) exposed organisms. These results corroborate with a nanoparticle-specific effect. © 2012 Elsevier Ltd. All rights reserved.
Sedgwick M.,University of Aarhus
Terrorism and Political Violence | Year: 2010
The ubiquity of use of the term "radicalization" suggests a consensus about its meaning, but this article shows through a review of a variety of definitions that no such consensus exists. The article then argues that use of the term is problematic not just for these reasons, but because it is used in three different contexts: the security context, the integration context, and the foreign-policy context. It is argued that each of these contexts has a different agenda, impacted in the case of the integration agenda by the rise of European "neo-nationalism," and so each uses the term "radical" to mean something different. The use of one term to denote at least three different concepts risks serious confusion. The proposed solution is to abandon the attempt to use "radicalization" as an absolute concept. © Taylor & Francis Group, LLC.
Hamann J.,University of Aarhus
Journal of Cosmology and Astroparticle Physics | Year: 2012
A number of recent analyses of cosmological data have reported hints for the presence of extra radiation beyond the standard model expectation. In order to test the robustness of these claims under different methods of constructing parameter constraints, we perform a Bayesian posterior-based and a likelihood profile-based analysis of current data. We confirm the presence of a slight discrepancy between posterior- and profile-based constraints, with the marginalised posterior preferring higher values of the effective number of neutrino species N eff. This can be traced back to a volume effect occurring during the marginalisation process, and we demonstrate that the effect is related to the fact that cosmic microwave background (CMB) data constrain N eff only indirectly via the redshift of matter-radiation equality. Once present CMB data are combined with external information about, e.g., the Hubble parameter, the difference between the methods becomes small compared to the uncertainty of N eff. We conclude that the preference of precision cosmological data for excess radiation is "real" and not an artifact of a specific choice of credible/confidence interval construction. © 2012 IOP Publishing Ltd and Sissa.
Frith C.D.,University College London |
Frith C.D.,University of Aarhus |
Frith C.D.,All Souls College
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2012
Metacognition concerns the processes by which we monitor and control our own cognitive processes. It can also be applied to others, in which case it is known as mentalizing. Both kinds of metacognition have implicit and explicit forms, where implicit means automatic and without awareness. Implicit metacognition enables us to adopt a we-mode, through which we automatically take account of the knowledge and intentions of others. Adoption of this mode enhances joint action. Explicit metacognition enables us to reflect on and justify our behaviour to others. However, access to the underlying processes is very limited for both self and others and our reports on our own and others' intentions can be very inaccurate. On the other hand, recent experiments have shown that, through discussions of our perceptual experiences with others, we can detect sensory signals more accurately, even in the absence of objective feedback. Through our willingness to discuss with others the reasons for our actions and perceptions, we overcome our lack of direct access to the underlying cognitive processes. This creates the potential for us to build more accurate accounts of the world and of ourselves. I suggest, therefore, that explicit metacognition is a uniquely human ability that has evolved through its enhancement of collaborative decision-making. © 2012 The Royal Society.
Damgaard C.K.,University of Colorado at Boulder |
Damgaard C.K.,University of Aarhus |
Lykke-Andersen J.,University of Colorado at Boulder |
Lykke-Andersen J.,University of California at San Diego
Genes and Development | Year: 2011
The response of cells to changes in their environment often requires coregulation of gene networks, but little is known about how this can occur at the post-transcriptional level. An important example of post-transcriptional coregulation is the selective translational regulation in response to growth conditions of mammalian mRNAs that encode protein biosynthesis factors and contain hallmark 5'-terminal oligopyrimidine tracts (5'TOP). However, the responsible trans-factors and the mechanism by which they coregulate 5'TOP mRNAs have remained elusive. Here we identify stress granule-associated TIA-1 and TIAR proteins as key factors in human 5'TOP mRNA regulation, which upon amino acid starvation assemble onto the 5' end of 5'TOP mRNAs and arrest translation at the initiation step, as evidenced by TIA-1/TIAR-dependent 5'TOP mRNA translation repression, polysome release, and accumulation in stress granules. This requires starvation-mediated activation of the GCN2 (general control nonderepressible 2) kinase and inactivation of the mTOR (mammalian target of rapamycin) signaling pathway. Our findings provide a mechanistic explanation to the long-standing question of how the network of 5'TOP mRNAs are coregulated according to amino acid availability, thereby allowing redirection of limited resources to mount a nutrient deprivation response. This presents a fundamental example of how a group of mRNAs can be translationally coregulated in response to changes in the cellular environment. © 2011 by Cold Spring Harbor Laboratory Press.
Hagen M.,Bielefeld University |
Wikelski M.,Max Planck Institute for Ornithology (Radolfzell) |
Kissling W.D.,University of Aarhus
PLoS ONE | Year: 2011
Background: Accurate estimates of movement behavior and distances travelled by animals are difficult to obtain, especially for small-bodied insects where transmitter weights have prevented the use of radio-tracking. Methodology/Principal Findings: Here, we report the first successful use of micro radio telemetry to track flight distances and space use of bumblebees. Using ground surveys and Cessna overflights in a Central European rural landscape mosaic we obtained maximum flight distances of 2.5 km, 1.9 km and 1.3 km for Bombus terrestris (workers), Bombus ruderatus (worker), and Bombus hortorum (young queens), respectively. Bumblebee individuals used large areas (0.25-43.53 ha) within one or a few days. Habitat analyses of one B. hortorum queen at the landscape scale indicated that gardens within villages were used more often than expected from habitat availability. Detailed movement trajectories of this individual revealed that prominent landscape structures (e.g. trees) and flower patches were repeatedly visited. However, we also observed long (i.e. >45 min) resting periods between flights (B. hortorum) and differences in flower-handling between bumblebees with and without transmitters (B. terrestris) suggesting that the current weight of transmitters (200 mg) may still impose significant energetic costs on the insects. Conclusions/Significance: Spatio-temporal movements of bumblebees can now be tracked with telemetry methods. Our measured flight distances exceed many previous estimates of bumblebee foraging ranges and suggest that travelling long distances to food resources may be common. However, even the smallest currently available transmitters still appear to compromise flower handling performance and cause an increase in resting behavior of bees. Future reductions of transmitter mass and size could open up new avenues for quantifying landscape-scale space use of insect pollinators and could provide novel insights into the behavior and requirements of bumblebees during critical life stages, e.g. when searching for mates, nest locations or hibernation sites. © 2011 Hagen et al.
Wiinow T.E.,Max Delbruck Center for Molecular Medicine |
Andersen O.M.,University of Aarhus
Journal of Cell Science | Year: 2013
Excessive proteolytic breakdown of the amyloid precursor protein (APP) to neurotoxic amyloid b peptides (Ab) by secretases in the brain is a molecular cause of Alzheimer disease (AD). According to current concepts, the complex route whereby APP moves between the secretory compartment, the cell surface and endosomes to encounter the various secretases determines its processing fate. However, the molecular mechanisms that control the intracellular trafficking of APP in neurons and their contribution to AD remain poorly understood. Here, we describe the functional elucidation of a new sorting receptor SORLA that emerges as a central regulator of trafficking and processing of APP. SORLA interacts with distinct sets of cytosolic adaptors for anterograde and retrograde movement of APP between the trans-Golgi network and early endosomes, thereby restricting delivery of the precursor to endocytic compartments that favor amyloidogenic breakdown. Defects in SORLA and its interacting adaptors result in transport defects and enhanced amyloidogenic processing of APP, and represent important risk factors for AD in patients. As discussed here, these findings uncovered a unique regulatory pathway for the control of neuronal protein transport, and provide clues as to why defects in this pathway cause neurodegenerative disease. © 2013 Published by The Company of Biologists Ltd.
Demant J.,University of Aarhus
International Journal of Drug Policy | Year: 2013
The nightclub as a space is presented as a free and hedonistic place for pleasure. This space is also part of a wider socio-spatial-economic framework in which various forms of regulation apply to clubbers and the cultivation of affects. This paper researches marginal and contested forms of experiences within a club as a way of understanding the complexities of pleasure. The study does so by addressing experiences through the concept of affects, which is situated within a framework of a non-representational theory of space. Anxiety, pride, anger, shame and embarrassment are embodied simultaneously with the affects of love, joy, sympathy and so on. Alcohol, illicit drugs, bouncers, music and other human or non-human actants are part of the place. It is within this heterogeneous assemblage that affects become embodied. The data consists of 273 cases from a large Copenhagen nightclub where guests have complained about being rejected or being given quarantine. The paper suggests that if the space of the club is approached as being more than a mono-affectual space of either risk or pleasure, then it would be possible to reduce conflicts and produce more inclusive spaces. © 2013 Elsevier B.V.
Kjaergaard M.B.,University of Aarhus
Pervasive and Mobile Computing | Year: 2011
Heterogeneous wireless clients measure signal strength differently. This is a fundamental problem for indoor location fingerprinting, and it has a high impact on the positioning accuracy. Mapping-based solutions have been presented that require manual and error-prone calibration for each new client. This article presents hyperbolic location fingerprinting, which records fingerprints as signal strength ratios between pairs of base stations instead of absolute signal strength values. This article also presents an automatic mapping-based method that avoids calibration by learning from online measurements. The evaluation shows that the solutions can address the signal strength heterogeneity problem without requiring extra manual calibration. © 2010 Elsevier B.V. All rights reserved.
Levin G.,University of Aarhus
Environmental Monitoring and Assessment | Year: 2013
A major obstacle to the conservation and management of semi-natural grassland (SNG) is the general lack of consistent and precise maps showing the extent and quality of this habitat type. SNG is related to, and influenced by, agricultural land use. Both intensive land use as well as a lack of extensive land use can reduce the extent and quality of SNG. For Denmark, this paper demonstrates how parcel-specific land-use data can be applied to detect localities with spatial convergences and conflicts between SNG and agricultural land use. Based on their respective influence on SNG, land use is aggregated into five major classes and spatially overlaid with existing nationally registered SNG. Results show that almost 11 % of all SNG is mapped either on cropped land or on rotational grassland, indicating a conflict between mapped SNG and land use. Thirty percent of SNG is mapped outside any agricultural land use, pointing to a lack of management. Fifty nine percent of SNG is mapped either on land receiving payments for grazing/mowing or on other land under extensive management, indicating a convergence between SNG and land use. Finally, 30 % of land receiving payments for grazing/mowing and 62 % of other land under extensive management does not contain any semi-natural habitat. Potential, as yet unmapped, SNG might exist in these localities. Based on these results it is argued that the application of parcel-specific land-use data could significantly improve monitoring of SNG. © 2012 Springer Science+Business Media B.V.
Zadegan R.M.,University of Aarhus |
Norton M.L.,Marshall University
International Journal of Molecular Sciences | Year: 2012
The exploitation of DNA for the production of nanoscale architectures presents a young yet paradigm breaking approach, which addresses many of the barriers to the self-assembly of small molecules into highly-ordered nanostructures via construct addressability. There are two major methods to construct DNA nanostructures, and in the current review we will discuss the principles and some examples of applications of both the tile-based and DNA origami methods. The tile-based approach is an older method that provides a good tool to construct small and simple structures, usually with multiply repeated domains. In contrast, the origami method, at this time, would appear to be more appropriate for the construction of bigger, more sophisticated and exactly defined structures. © 2012 by the authors; licensee MDPI, Basel, Switzerland.
Sorensen M.D.,University of Aarhus
Nature protocols | Year: 2011
Here we describe a new method applying phage-displayed antibody libraries to the selection of antibodies against a single identified cell on a glass slide. This is the only described method that has successfully achieved selection of antibodies against a single rare cell in a heterogeneous population of cells. The phage library is incubated with the slide containing the identified rare cell of interest; incubation is followed by UV irradiation while protecting the target cell with a minute disc. The UV light inactivates all phages outside the shielded area by cross-linking the DNA constituting their genomes. The expected yield is between one and ten phage particles from a single cell selection. The encoded antibodies are subsequently produced monoclonally and tested for specificity. This method can be applied within a week to carry out ten or more individual cell selections. Including subsequent testing of antibody specificity, a specific antibody can be identified within 2 months.
Riber A.B.,University of Aarhus
Applied Animal Behaviour Science | Year: 2010
Use of nest boxes is an important part of the behavioural repertoire of laying hens kept under commercial conditions. A special form of nest box use is gregarious nesting, which occurs when a hen given the choice between an occupied and an unoccupied nest site chooses the occupied nest site. Knowledge about gregarious nesting behaviour is limited, but welfare problems likely to be associated with it are scratches/wounds, heat stress, increased level of aggression, and excessive expenditure of energy. The benefits of the producer may also be affected by gregarious nesting due to an increased risk of broken or dirty eggs. The main objectives were to investigate the use of nest boxes according to their position and the occurrence of gregarious nesting with age. Twelve groups of 15 Isa Warren hens were housed in pens each containing three adjacent roll-out nest boxes only differing in position (left + corner, middle, and right). Nesting behaviour was video recorded for 5 days in each of five distinct periods: age 20, 26, 32, 38, and 44 weeks. The total number of visits and the number of gregarious visits were higher in the left nest box than in the other two nest boxes at all ages and higher at age 20 weeks than at the other ages (P < 0.001). Also, more eggs were laid in the left nest box than in the other two nest boxes (P < 0.001) and this did not change with age (P > 0.05). The proportion of gregarious visits of the total number of visits, where the hens had a choice between gregarious or solitary nesting, was higher at age 20 weeks than at older ages (P < 0.001). It is suggested that young hens inexperienced in nest box selection will tend to visit the same nest boxes as more experienced individuals. As they gain experience individuals will tend to rely more on their own experiences in selection of nest locations, causing the found decrease in frequency of gregarious nesting after age 20 weeks. A general preference for corner and end nest boxes is suggested to have triggered the initial use of the left nest box by the first hens coming into lay and to have maintained the observed high level of gregarious nesting throughout the study. © 2010 Elsevier B.V. All rights reserved.
Gatti C.,CNR Institute of Molecular Science and Technologies |
Gatti C.,University of Aarhus
Structure and Bonding | Year: 2012
This chapter deals with the source function (SF) descriptor, originally put forth by Bader and Gatti back in 1998. After a brief review on how this descriptor is defined and what it physically represents, the various forms through which the SF may be analyzed are presented in some detail. The relationships between atomic SF contributions and chemical bond nature are analyzed in some prototypical cases, and the capability of the SF to neatly reveal π-electron conjugation directly from the electron distribution and independently from any MO scheme or decomposition is introduced. Applications of the SF to chemistry from the literature are reviewed and critically discussed, including the use of the SF to assess chemical transferability or to describe chemical bonding in challenging situations, like for instance the short-strong hydrogen bonds in π-conjugated frameworks or the metal-metal and metal-ligand interactions in the organometallic complexes. Comparison with the insight obtained from other bond topological descriptors is given, emphasizing the special role the SF has of being directly derivable from experimental electron density distributions and to so provide an ideal tool to compare experiment and theory. The robustness of the SF descriptor against changes in the models used to derive electron densities from theory of experiment is detailed. First results on using the SF to define an unambiguous full population analysis are outlined. The possible ways of further decomposing the atomic SF in chemically meaningful additive pieces, such as core and valence atomic contributions, are analyzed in view of their potential insight and degree of arbitrariness. © 2011 Springer-Verlag Berlin Heidelberg.
Gissel H.,University of Aarhus
American Journal of Physiology - Regulatory Integrative and Comparative Physiology | Year: 2010
Electroporation is a technique used in vitro, ex vivo, and in vivo to permeabilize cell membranes. The effect on the tissue describes a continuum ranging from mild perturbations to massive tissue damage. Thus care should be taken when choosing pulses for a given application. Here the effects of electroporation paradigms ranging from severe to very gentle permeabilization were investigated on soleus, mainly composed of slow-twitch fibers, and extensor digitorum longus (EDL) and tibialis anterior (TA), almost exclusively composed of fast-twitch fibers. Five key physiological parameters were studied: force, muscle Na+, K+, and Ca2+ content, and plasma lactate dehydrogenase activity. Four-week-old Wistar rats were anesthetized, and the lower part of the hind leg was electroporated. Blood samples were collected from the tail vein, and at the times indicated animals were killed and TA, EDL, and soleus muscles were collected for analysis of force and ion contents. Muscles were given eight high-voltage pulses of 100-μs duration (8HV) at varying field intensity, one short high-voltage pulse combined with one long low-voltage pulse (HVLV), or eight mediumvoltage pulses of 20-ms duration (8MV). Intensity of the electrical field strength was determinant for the degree of changes observed in the muscle. Field strengths below 300 V/cm did not give rise to measurable changes, whereas 8HV pulses at high field intensities (1,200 V/cm) caused severe and long-lasting damage to the muscle. Interestingly, the damage was more pronounced in EDL and TA compared with soleus, possibly because of the difference in fiber type composition. HVLV only caused temporary changes, with force and ion content being normalized by 4 h, suggesting that this pulse combination may be useful for the introduction of ions and molecules (e.g., DNA) into muscle cells. © 2010 the American Physiological Society.
Bindi M.,University of Florence |
Olesen J.E.,University of Aarhus
Regional Environmental Change | Year: 2011
Human activities are projected to lead to substantial increases in temperature that will impact northern Europe during winter and southern Europe during summer. Moreover, it is expected that these changes will cause increasing water shortages along the Mediterranean and in the south-west Balkans and in the south of European Russia. The consequences on the European agricultural ecosystems are likely to vary widely depending on the cropping system being investigated (i. e. cereals vs. forage crops vs. perennial horticulture), the region and the likely climate changes. In northern Europe, increases in yield and expansion of climatically suitable areas are expected to dominate, whereas disadvantages from increases in water shortage and extreme weather events (heat, drought, storms) will dominate in southern Europe. These effects may reinforce the current trends of intensification of agriculture in northern and western Europe and extensification and abandonment in the Mediterranean and south-eastern parts of Europe. Among the adaptation options (i.e. autonomous or planned adaptation strategies) that may be explored to minimize the negative impacts of climate changes and to take advantage of positive impacts, changes in crop species, cultivar, sowing date, fertilization, irrigation, drainage, land allocation and farming system seem to be the most appropriate. In adopting these options, however, it is necessary to consider the multifunctional role of agriculture and to strike a variable balance between economic, environmental and economic functions in different European regions. © 2010 Springer-Verlag.
Jensen M.B.,University of Aarhus
Applied Animal Behaviour Science | Year: 2012
The aim of this study was to investigate behavioural changes before and after calving in dairy cows in order to describe behavioural signs of imminent calving and of cows' recovery after calving. Thirty-two multiparous Danish Holstein Frisian cows with an unassisted calving were studied from 96. h before until 96. h after calving while housed in individual calving pens. Data on behaviour were obtained via video recordings and accelerometers attached to the cows' legs. Cows spent less time lying, had more lying bouts and were more active the day before calving as compared to 2-4 days before calving. The number of lying bouts and the level of activity increased throughout the 6. h prior to calving. During the last 2. h prior to calving the duration of contractions and the number of times the cow turned her head towards the abdomen were increased, while the duration of feeding and drinking was decreased. Within minutes after calving cows stood up and licked their calves; second parity cows had a longer latency to stand than later parity cows. Sniffing and licking the calf peaked during the first hour after calving and decreased during the five successive hours, while calves' sniffing the cow peaked during the second hour after birth. The high level of cows' sniffing and licking their calves coincided with low levels of lying and feeding during the first hours after calving. Compared to the first 6-h period after calving, cows spent more time lying and feeding during the following two 6-h periods, while the duration of sniffing and licking calf and the number of lying bouts decreased throughout the 24. h after calving. Calves spent the most time sniffing the cow and suckling during the first 6-h period after birth, while the time spent lying increased and the number of lying bouts decreased throughout the 24. h following birth. Cows spent more time lying on the second day after calving than on the first day after calving. The results show marked behavioural changes during the last 6. h prior to calving and suggest that behavioural changes may be useful indicators of imminent calving. Furthermore, the results show that the first hours after calving contain most cow-calf interaction. These behaviours were at the expense of the cows' resting and feeding, which showed a rebound during the subsequent hours and the following day. This suggests that ample opportunity to rest and feed during the first days after calving may be beneficial for cow welfare. © 2012 Elsevier B.V.
Riber A.B.,University of Aarhus
Applied Animal Behaviour Science | Year: 2012
Under natural conditions, the feral hen (Gallus gallus domesticus) will choose a nest location away from the flock, whereas under commercial conditions, the domestic hen will often choose the same nest as other hens have used or are still using. Simultaneous nest sharing causes several welfare problems to laying hens, and egg production may also be negatively affected. Understanding what causes this difference in nest location selection may provide solutions to the problems associated with simultaneous nest sharing. The aims were to investigate whether a commercial strain of laying hens normally housed in intensive production systems share nests under semi-natural conditions and to describe the behaviour if this behaviour occurred. Twenty 15 weeks old hens were released into an 840m 2 enclosure with multiple options for natural and semi-natural nest sites. Over a 63-day period records were made daily of each nest with regard to number of eggs, position, and materials used. On five mornings nesting behaviour was observed. Nest sharing occurred on all but the first 5 days of egg-laying. The majority of hens (n=14) chose to visit an occupied nest at least once, but no hens exclusively used occupied nests. Visits in shared nests lasted longer than visits in undisturbed nests (13min 50s (±4min and 57s) vs 30min 44s (±4min and 55s); P<0.001). Fifteen nests were used. All shared nests (n=5) were placed up against the borders, whereas the majority of non-shared nests (n=7 out of 10) were placed more than 1m away from the borders (P=0.002). Some results indicate that nest sharing was caused by environmental restrictions. © 2011 Elsevier B.V.
Sanderson H.,University of Aarhus
Water Science and Technology | Year: 2011
Trace amounts of pharmaceuticals have been detected in surface waters in the nano- to microgram per liter range, and in drinking water in the nanogram/L range. The environmental risks of pharmaceuticals in surface waters have been evaluated and generally found to be low if the wastewater is treated before release to the environment. The human health risks of trace amounts of pharmaceuticals in drinking water have however not been evaluated in any great depth. Preliminary screening level assessments suggest risk to be low - but the public and decision-makers are concerned and would like the matter investigated more thoroughly, especially with regards to mixture effects, chronic long-term effects and sensitive sub-populations. The World Health Organization is currently evaluating the need for credible health based guidance associated with low concentrations of pharmaceuticals in drinking water. The aim of this paper is to summarize the state-of-the-science and the ongoing international debate on the topic. © IWA Publishing 2011.
Walter S.,University of Aarhus |
Nicholson P.,John Innes Center |
Doohan F.M.,University College Dublin
New Phytologist | Year: 2010
TheFusarium species Fusarium graminearum and Fusarium culmorum, which are responsible for Fusarium head blight (FHB) disease, reduce world-wide cereal crop yield and, as a consequence of their mycotoxin production in cereal grain, impact on both human and animal health. Their study is greatly promoted by the availability of the genomic sequence of F. graminearum and transcriptomic resources for both F. graminearum and its cereal hosts. Functional genomic, proteomic and metabolomic studies, in combination with targeted mutagenesis or transgenic studies, are unravelling the complex mechanisms involved in Fusarium infection, penetration and colonization of host tissues, and host avoidance thereof. This review illuminates and integrates emerging knowledge regarding the molecular crosstalk between Fusarium and its small-grain cereal hosts. An understanding of the complexity of the host-pathogen interactions will be instrumental in designing new efficient strategies for the control of FHB disease. © 2009 New Phytologist.
Happe F.,Kings College London |
Frith U.,University College London |
Frith U.,University of Aarhus
Journal of Child Psychology and Psychiatry and Allied Disciplines | Year: 2014
As a starting point for our review we use a developmental timeline, starting from birth and divided into major developmental epochs defined by key milestones of social cognition in typical development. For each epoch, we highlight those developmental disorders that diverge from the normal developmental pattern, what is known about these key milestones in the major disorders affecting social cognition, and any available research on the neural basis of these differences. We relate behavioural observations to four major networks of the social brain, that is, Amygdala, Mentalizing, Emotion and Mirror networks. We focus on those developmental disorders that are characterized primarily by social atypicality, such as autism spectrum disorder, social anxiety and a variety of genetically defined syndromes. The processes and aspects of social cognition we highlight are sketched in a putative network diagram, and include: agent identification, emotion processing and empathy, mental state attribution, self-processing and social hierarchy mapping involving social 'policing' and in-group/out-group categorization. Developmental disorders reveal some dissociable deficits in different components of this map of social cognition. This broad review across disorders, ages and aspects of social cognition leads us to some key questions: How can we best distinguish primary from secondary social disorders? Is social cognition especially vulnerable to developmental disorder, or surprisingly robust? Are cascading notions of social development, in which early functions are essential stepping stones or building bricks for later abilities, necessarily correct? © 2013 The Authors. Journal of Child Psychology and Psychiatry © 2013 Association for Child and Adolescent Mental Health.
Aagaard K.,University of Aarhus
Science and Public Policy | Year: 2015
The question of how the incentives of national performance-based research funding systems affect local management practices within the higher education sector has high empirical and theoretical importance, but has so far received limited attention. From a traditional organization theory perspective the Norwegian system represents a puzzle: it is of marginal economic importance and the external pressure to fully implement the system at local levels is weak. A loose coupling between the national system and the local implementation would therefore be expected. Yet, in many instances we document a quite tight coupling between system-level incentives and local practices. Based on a recent evaluation of the Norwegian model, which identifies a number of indirect mechanisms that contribute to the trickling down of incentives, this paper shows that traditional coupling perspectives are oversimplistic. A large variation across institutions, fields and departments is, however, also observed and possible explanations for this are discussed. © The Author 2015. Published by Oxford University Press. All rights reserved.
Svendsen G.T.,University of Aarhus
Environmental Policy and Governance | Year: 2011
How should we evaluate and regulate the impacts of lobbying in the European Union (EU)? The current lack of transparency around lobbying activities and the absence of formal regulation mean that a hidden lobbying problem may prevail. The tentative case study of green industries in the EU is illustrative. The wind turbine industry, for example, benefits from ambitious environmental target levels for greenhouse gas reductions that will increase the future market for renewable energy. In contrast, for example, no environmental target levels exist that increase the future market shares of organic farming. Rational choice theory suggests that lobbying and group size advantages can explain the observed difference in achieving environmental target levels. The EU may learn from the US legislation as a starting point for a best-practice solution and future evaluation of impacts of lobbying in the EU. © 2011 John Wiley & Sons, Ltd and ERP Environment.
Da Cunha J.V.,European University of Portugal |
Da Cunha J.V.,University of Aarhus
MIS Quarterly: Management Information Systems | Year: 2013
The production of performance data in organizations is often described as a functional process that managers enforce on their employees to provide leaders with accurate information about employees' work and their achievements. This study draws on a 15-month ethnography of a desk sales unit to build a dramaturgical model that explains how managers participate in the production of performance data to impress rather than inform leaders. Research on management information systems is reviewed to outline a protective specification of this model where managers participate in the production of performance data to suppress information that threatens the image they present to leaders. Ethnographic data about the production and use of performance records and performance reports in a desk sales unit is examined to induce an exploitive specification of this dramaturgical model. This specification explains how people can take advantage of the opportunities, rather than just avoid the threats that performance data presents for impression management. It also demonstrates how managers can participate in the production of performance data to create an idealized version of their accomplishments and that leaders reify these data by using them in their own attempts at impressing others. By doing so, leaders and managers turn information systems into store windows to show achievement upward instead of transparent windows to monitor compliance downward.
Jensen F.,University of Aarhus
Theoretical Chemistry Accounts | Year: 2010
The previously proposed pcJ-n basis sets, optimized for calculating indirect nuclear spin-spin coupling constants using density functional methods, are re-evaluated for finding the optimum contraction scheme as a compromise between computational efficiency and minimizing contraction errors. An exhaustive search is performed for the H 2, F 2 and P 2 molecules, and candidates for optimum contraction schemes are evaluated for a larger test set of 21 molecules. Using the criterion that the contraction error should not exceed the basis set error relative to the basis set limit, the optimum contraction is defined for each basis set. The results show that it is difficult to contract basis sets for calculating spin-spin coupling constants to any significant degree without losing the inherent accuracy. The work provides guidelines for searching for optimum contraction schemes for other properties and/or at theoretical levels where a systematic search is impractical. © 2009 Springer-Verlag.
Matrone C.,University of Aarhus
BioEssays | Year: 2013
Emerging evidence supports the role for the intracellular domains of amyloid precursor protein (APP) in the physiology and function of APP. In this short report, I discuss the hypothesis that mutation of Tyr682 on the Y682ENPTY687 C-terminal motif of APP may be directly or indirectly associated with alterations in APP functioning and activity, leading to neuronal defects and deficits. Mutation of Tyr682 induces an early and progressive age-dependent cognitive and locomotor decline that is associated with a loss of synaptic connections, a decrease in cholinergic tone, and defects in NGF signaling. These findings support a model in which APP-C-terminal domain exerts a pathogenic function in neuronal development and decline, and suggest that Tyr682 potentially could modulate the properties of APP metabolites in humans. © 2013 The Author. Bioessays published by WILEY Periodicals, Inc.
Fedosov S.N.,University of Aarhus
Clinica Chimica Acta | Year: 2013
Background: Vitamin B12 deficiency is diagnosed by measurements of total B12, holo-transcobalamin (holoTC), methylmalonic acid (MMA) and total homocysteine (Hcy) in blood. Results of the individual biochemical tests are often contradictory. Here the four markers are combined to achieve a more reliable indication of the B12 status. The results are aligned with hemoglobin and cognitive score. Methods: Databases from the literature were plotted in coordinates x=(holoTC·B12)1/2, y=1/2·log10(MMA·Hcy), where distribution of points revealed the subgroups characterized by logarithmic ratios lr=log10[(holoTC·B12)/(MMA·Hcy)]. Distance between the subgroups w=lrTest-lrNormal was taken as a robust biochemical indicator of B12 status ("wellness parameter"). Results: The dependence of lrNormal vs. age was described by a mathematical function to correct parameter w. The B12 status was defined as "excellent" (w≈+0.4), "normal" (w≈0), "transitional" (w≈-0.5), "deficient" (w≈-1.7) and "pernicious" (w≈-3.0). The groups of individuals with either w≥0 or w≤-1 exhibited the statistically significant differences in both hemoglobin and cognitive score. Analogous assessment of B12 status by the individual markers agreed with only one out of two physiological characteristics. Conclusion: Combined parameter w is a reliable diagnostic tool. © 2013 Elsevier B.V.
Pedersen T.Q.,University of Aarhus
Journal of Forecasting | Year: 2015
Using quantile regression this paper explores the predictability of the stock and bond return distributions as a function of economic state variables. The use of quantile regression allows us to examine specific parts of the return distribution such as the tails and the center, and for a sufficiently fine grid of quantiles we can trace out the entire distribution. A univariate quantile regression model is used to examine the marginal stock and bond return distributions, while a multivariate model is used to capture their joint distribution. An empirical analysis on US data shows that economic state variables predict the stock and bond return distributions in quite different ways in terms of, for example, location shifts, volatility and skewness. Comparing the different economic state variables in terms of their out-of-sample forecasting performance, the empirical analysis also shows that the relative accuracy of the state variables varies across the return distribution. Density forecasts based on an assumed normal distribution with forecasted mean and variance is compared to forecasts based on quantile estimates and, in general, the latter yields the best performance. © 2015 John Wiley and Sons, Ltd.
Kristensen T.G.,University of Aarhus
Journal of Mathematical Chemistry | Year: 2010
The Tanimoto coefficient has previously been proven to be a metric, but only in the case of binary valued vectors. Moreover, it has been proven that the Tanimoto coefficient for real valued vectors is not a metric. This means that it is not immediately possible to use metric based data structures for accelerating Tanimoto queries. This note presents a method for transforming Tanimoto queries into range queries in Euclidian space, making it possible to use metric data structures, as well as data structures designed for Euclidian space. © 2010 Springer Science+Business Media, LLC.
Svejvig P.,University of Aarhus
International Journal of Enterprise Information Systems | Year: 2013
This paper examines the use of institutional theory as a conceptually rich lens to study social issues of enterprise systems (ES) research. More precisely, the purpose is to categorize current ES research using institutional theory to develop a conceptual model that advances ES research. Key institutional features are presented such as isomorphism, rationalized myths, and bridging macro and micro structures, and institutional logics and their implications for ES research are discussed. Through a literature review of 181 articles, of which 18 papers are selected, the author's built a conceptual model that advocates multi-level and multitheory approaches and applies newer institutional aspects such as institutional logics. The findings show that institutional theory in ES research is in its infancy and adopts mainly traditional institutional aspects like isomorphism, with the organization as the level of analysis, and in several cases it is complemented by structuration theory and other theories. Copyright © 2013, IGI Global.
Bochenkova A.V.,University of Aarhus
Faraday discussions | Year: 2013
The anionic wild-type Green Fluorescent Protein (GFP) chromophore defines an entire class of naturally occurring chromophores, which are based on the oxydized tyrosine side chain. The GFP chromophore exhibits an enriched photoinduced non-adiabatic dynamics in the multiple excited-state decay channels. Deactivation includes vibrational resonant photodetachment and internal conversion. Here, we provide detailed insight into the efficiency of different vibrational modes in promoting a selective photoresponse in the bare GFP chromophore anion. We introduce a general theoretical model that is capable of accounting for the alternative non-equivalent pathways in internal conversion, and we outline the factors, by which the photo-initiated response may be altered in this channel. The topography around the planar minimum in S1 and the two distinct types of the S1/S0 conical intersections obtained through high-level ab initio calculations provide direct support to the proposed model. There are mode-selective ways to control the photoresponse and to direct it towards a single excited-state decay channel. By tuning the excitation wavelength, the photoresponse may be directed towards the ultrafast non-statistical electron emission coupled with vibrational (de)coherence, whereas a vibrational pre-excitation in the ground state may lead to the ultrafast non-statistical internal conversion through a conical intersection. We also discuss the implication of our results to the photo-initiated non-adiabatic dynamics in the proteins.
Brincker R.,University of Aarhus |
Lopez-Aenlle M.,University of Oviedo
Journal of Sound and Vibration | Year: 2015
In this paper the sensitivity of the mode shapes of two closely spaced eigenvalues are studied. It is well known that in case of repeated eigenvalues, the meaningful quantity is not the two individual mode shapes, but rather the subspace defined by the two mode shapes. Following the ideas of a principle that has been released for publishing recently denoted as the local correspondence (LC) principle, it is shown, that in the case of a set of two closely spaced eigenvalues, the mode shapes become highly sensitive to small changes of the system. However, if the two closely spaced eigenvalues have a reasonable frequency distance to all other eigenvalues of the system, then a linear transformation exists between the set of perturbed and unperturbed mode shapes describing the significant changes as a rotation in the initial subspace defined by the two mode shapes. Closed form solutions are given for general combined mass and stiffness perturbations, and it is shown that there is a smooth transition from the case of moderate sensitivity of the mode shapes towards the case of repeated eigenvalues where the sensitivity goes to infinite. In case of "nearly repeated eigenvalues" the perturbed set of mode shapes can be found by solving a special eigenvalue problem for the two closely spaced eigenvalues. The theory is illustrated and compared with the exact solution for a simple 3 dof system. © 2014 Elsevier Ltd. All rights reserved.
Vilhelmsen L.B.,University of Aarhus |
Walton K.S.,Georgia Institute of Technology |
Sholl D.S.,Georgia Institute of Technology
Journal of the American Chemical Society | Year: 2012
Understanding the adsorption and mobility of metal-organic framework (MOF)-supported metal nanoclusters is critical to the development of these catalytic materials. We present the first theoretical investigation of Au-, Pd-, and AuPd-supported clusters in a MOF, namely MOF-74. We combine density functional theory (DFT) calculations with a genetic algorithm (GA) to reliably predict the structure of the adsorbed clusters. This approach allows comparison of hundreds of adsorbed configurations for each cluster. From the investigation of Au 8, Pd 8, and Au 4Pd 4 we find that the organic part of the MOF is just as important for nanocluster adsorption as open Zn or Mg metal sites. Using the large number of clusters generated by the GA, we developed a systematic method for predicting the mobility of adsorbed clusters. Through the investigation of diffusion paths a relationship between the cluster's adsorption energy and diffusion barrier is established, confirming that Au clusters are highly mobile in the MOF-74 framework and Pd clusters are less mobile. © 2012 American Chemical Society.
Zinner N.T.,University of Aarhus
Few-Body Systems | Year: 2013
Near a Feshbach resonance, the two-body scattering length can assume any value. When it approaches zero, the next-order term given by the effective range is known to diverge. We consider the question of whether this divergence (and the vanishing of the scattering length) is accompanied by an anomalous solution of the three-boson Schrödinger equation similar to the one found at infinite scattering length by Efimov. Within a simple zero-range model, we find no such solutions, and conclude that higher-order terms do not support Efimov physics. © 2012 Springer-Verlag.
de Almeida A.M.,Instituto Of Investigacao Cientifica Tropical |
Bendixen E.,University of Aarhus
Journal of Proteomics | Year: 2012
The pig (Sus scrofa) is one of the most important animal species used for meat production worldwide, playing a fundamental role in numerous cultures from Southern Europe to the Pacific Islands. Additionally, it is broadly used as an experimental animal for several purposes, from physiological studies to drug testing and surgical training. Proteomics studies have covered both physiological and biomedical application studies of pig to a much greater extent than for any other farm animal. Despite this fact, no review seems to be available on the application of proteomics to production aspects in pig. The aim of this article is to provide a review on such applications of proteomics to the pig species. The article is divided in three parts. The first is dedicated to productive characterization and includes aspects related to reproduction and meat science. The second concerns the management of health and disease in production. Finally, the third part concerns the use of the pig as a model organism in biomedical research. This article is part of a Special Issue entitled: Farm animal proteomics. © 2012 Elsevier B.V.
Grantzau T.,Aarhus University Hospital |
Thomsen M.S.,Aarhus University Hospital |
Vaeth M.,University of Aarhus |
Overgaard J.,Aarhus University Hospital
Radiotherapy and Oncology | Year: 2014
Background Several epidemiological studies have reported increased risks of second lung cancers after breast cancer irradiation. In this study we assessed the effects of the delivered radiation dose to the lung and the risk of second primary lung cancer. Methods We conducted a nested case-control study of second lung cancer in a population based cohort of 23,627 early breast cancer patients treated with post-operative radiotherapy from 1982 to 2007. The cohort included 151 cases diagnosed with second primary lung cancer and 443 controls. Individual dose-reconstructions were performed and the delivered dose to the center of the second lung tumor and the comparable location for the controls were estimated, based on the patient specific radiotherapy charts. Results The median age at breast cancer diagnosis was 54 years (range 34-74). The median time from breast cancer treatment to second lung cancer diagnosis was 12 years (range 1-26 years). 91% of the cases were categorized as ever smokers vs. 40% among the controls. For patients diagnosed with a second primary lung cancer five or more years after breast cancer treatment the rate of lung cancer increased linearly with 8.5% per Gray (95% confidence interval = 3.1-23.3%; p < 0.001). This rate was enhanced for ever smokers with an excess rate of 17.3% per Gray (95% CI = 4.5-54%; p < 0.005). Conclusions Second lung cancer after radiotherapy for early breast cancer is associated with the delivered dose to the lung. Although the absolute risk is relative low, the growing number of long-time survivors after breast cancer treatment highlights the need for advances in normal tissue sparing radiation techniques. © 2014 Elsevier Ireland Ltd.
Svane A.M.,University of Aarhus
Discrete and Computational Geometry | Year: 2015
Suppose an r-regular set is sampled on a random lattice. A fast algorithm for estimating the integrated mean curvature is to use a weighted sum of 2×⋯×2 configuration counts. We show that for a randomly translated lattice, no asymptotically unbiased estimator of this type exists in dimensions larger than two, while for stationary isotropic lattices, asymptotically unbiased estimators are plenty. The basis for this is a formula for the asymptotic behavior of hit-or-miss transforms of r-regular sets. © 2015, Springer Science+Business Media New York.
Zinner N.T.,University of Aarhus
Journal of Physics A: Mathematical and Theoretical | Year: 2012
We consider the spectrum of two ultracold harmonically trapped atoms interacting via short-range interactions. The Green function approach is used to unify the two- and three-dimensional cases. We derive criteria for the universality of the spectrum, i.e. its independence of the details of the short-range interaction. The results in three dimensions are exemplified for narrow s-wave Feshbach resonances and we show how effective range corrections can modify the rearrangement of the level structure. However, this requires extremely narrow resonances or very tight traps that are not currently experimentally available. In the two-dimensional case, we discuss the p-wave channel in detail and demonstrate how the non-universality of the spectrum arises within the Green function approach. We then show that the spectrum is not particularly sensitive to the short-distance details in the case when the two-body interaction has a bound state. © 2012 IOP Publishing Ltd.
Hannestad S.,University of Aarhus
Progress in Particle and Nuclear Physics | Year: 2010
Cosmology provides an excellent laboratory for testing various aspects of neutrino physics. Here, I review the current status of cosmological searches for neutrino mass, as well as other properties of neutrinos. Future cosmological probes of neutrino properties are also discussed in detail. © 2010 Elsevier B.V. All rights reserved.
Andersson K.-E.,University of Aarhus
Autonomic Neuroscience: Basic and Clinical | Year: 2015
It is well established that in most species, exocytotic vesicular release of ATP from parasympathetic neurons contributes to contraction of the bladder. However, ATP is released not only from parasympathetic nerves, but also from the urothelium. During bladder filling, the urothelium is stretched and ATP is released from the umbrella cells thereby activating mechanotransduction pathways. ATP release can also be induced by various mediators present in the urine and and/or released from nerves or other components of the lamina propria. Urothelial release of ATP is mainly attributable to vesicular transport or exocytosis and, to a smaller extent, to pannexin hemichannel conductive efflux. After release, ATP acts on P2X3 and P2X2/3 receptors on suburothelial sensory nerves to initiate the voiding reflex and to mediate the sensation of bladder filling and urgency. ATP also acts on suburothelial interstitial cells/myofibroblasts generating an inward Ca2+ transient that via gap junctions could provide a mechanism for long-distance spread of signals from the urothelium to the detrusor muscle. ATP release can be affected by urological diseases, e.g., interstitial cystitis and both the mechanisms of release and the receptors activated by ATP may be targets for future drugs for treatment of lower urinary tract disorders. © 2015 Elsevier B.V.
Jensen F.,University of Aarhus
Journal of Chemical Physics | Year: 2013
Polarization consistent basis sets, optimized for density functional calculations, are proposed for the transition metals Sc-Zn. The basis set composition in terms of number of primitive functions and the contraction is defined based on energetic analyses of atoms and molecules along the lines used in previous work and on the performance for molecular systems. The performance for atomization energies and dipole moments is compared to other widely used basis sets, and it is shown that the new basis sets allow a systematic reduction of basis set errors and, in general, have basis set errors lower than or at par with existing ones. © 2013 American Institute of Physics.
Germs R.,University of Groningen |
Goldengorin B.,University of Groningen |
Turkensteen M.,University of Aarhus
Computers and Operations Research | Year: 2012
In this paper, we develop a new tolerance-based Branch and Bound algorithm for solving NP-hard problems. In particular, we consider the asymmetric traveling salesman problem (ATSP), an NP-hard problem with large practical relevance. The main algorithmic contribution is our lower bounding strategy that uses the expected costs of including arcs in the solution to the assignment problem relaxation of the ATSP, the so-called lower tolerance values. The computation of the lower bound requires the calculation of a large set of lower tolerances. We apply and adapt a finding from  that makes it possible to compute all lower tolerance values efficiently. Computational results show that our Branch and Bound algorithm exhibits very good performance in comparison with state-of-the-art algorithms, in particular for difficult clustered ATSP instances. © 2011 Elsevier Ltd.
Lenoir J.,University of Picardie Jules Verne |
Svenning J.-C.,University of Aarhus
Ecography | Year: 2015
Poleward and upward shifts are the most frequent types of range shifts that have been reported in response to contemporary climate change. However, the number of reports documenting other types of range shifts - such as in east-west directions across longitudes or, even more unexpectedly, towards tropical latitudes and lower elevations - is increasing rapidly. Recent studies show that these range shifts may not be so unexpected once the local climate changes are accounted for. We here provide an updated synthesis of the fast-moving research on climate-related range shifts. By describing the current state of the art on geographical patterns of species range shifts under contemporary climate change for plants and animals across both terrestrial and marine ecosystems, we identified a number of research shortfalls. In addition to the recognised geographic shortfall in the tropics, we found taxonomic and methodological shortfalls with knowledge gaps regarding range shifts of prokaryotes, lowland range shifts of terrestrial plants, and bathymetric range shifts of marine plants. Based on this review, we provide a research agenda for filling these gaps. We outline a comprehensive framework for assessing multidimensional changes in species distributions, which should then be contrasted with expectations based on climate change indices, such as velocity measures accounting for complex local climate changes. Finally, we propose a unified classification of geographical patterns of species range shifts, arranged in a bi-dimensional space defined by species' persistence and movement rates. Placing the observed and expected shifts into this bi-dimensional space should lead to more informed assessments of extinction risks. © 2014 The Authors.
Thomsen M.S.,University of Aarhus
Aquatic Invasions | Year: 2010
Relatively few studies have aimed to test if invasive species have positive effects on native species, for example via formation of habitat or by amelioration of environmental stress-conditions. The red macroalga Gracilaria vermiculophylla, from the West Pacific, is invading estuarine mudflat and seagrass habitats along East Pacific and East and West Atlantic coastlines. I tested if low (55-110 g WW m-2) and high (220-440 g WW m-2) densities of G. vermiculophylla have positive or negative effects on the macroinvertebrates (> 2 mm) that inhabit Zostera marina seagrass beds. The experiment was conducted over 34 days at both 0.5 and 2 m depth at Snaptun Harbor, Denmark. I found positive effects of Gracilaria on most invertebrates, with statistically significant results for "all invertebrates", "gastropods", and "bivalves", and a near-significant result for "crustaceans". Both quantitative and qualitative habitat-resource models may explain these positive effects; i.e. "more habitats" exist in the presence of Gracilaria and/or the "habitat differs" between Gracilaria and Zostera vegetation. Future studies should test these two general explanatory models and quantify (a) if density thresholds exists were effects shift from positive to negative, (b) specific mechanism whereby positive effects occur, (c) if Gracilaria provide a novel or substitute drift algal habitat, and (d) the larger-scale ecosystem implications of this invasion. © 2010 The Author(s).
Liu L.,University of Aarhus
Nature Nanotechnology | Year: 2015
Synthetic polymers are ubiquitous in the modern world, but our ability to exert control over the molecular conformation of individual polymers is very limited. In particular, although the programmable self-assembly of oligonucleotides and proteins into artificial nanostructures has been demonstrated, we currently lack the tools to handle other types of synthetic polymers individually and thus the ability to utilize and study their single-molecule properties. Here we show that synthetic polymer wires containing short oligonucleotides that extend from each repeat can be made to assemble into arbitrary routings. The wires, which can be more than 200 nm in length, are soft and bendable, and the DNA strands allow individual polymers to self-assemble into predesigned routings on both two- and three-dimensional DNA origami templates. The polymers are conjugated and potentially conducting, and could therefore be used to create molecular-scale electronic or optical wires in arbitrary geometries. © 2015 Nature Publishing Group
Laursen T.M.,University of Aarhus |
Laursen T.M.,Nordic School of Public Health
Schizophrenia Research | Year: 2011
The objective was to estimate life-expectancy (average age at death) among these persons and make a comparison to people in the general population. Methods: Life-expectancy was calculated by means of survival analysis techniques using the entire Danish population as a cohort. Results: Life-expectancy was 18.7. years shorter for schizophrenic men compared to men in the general population. Corresponding numbers for schizophrenic women was 16.3. years, for bipolar men 13.6. years, and for bipolar women 12.1. years. Conclusions: Life-expectancy was much shorter in persons with schizophrenia or bipolar disorder. Excess mortality from physical diseases and medical conditions exerts a far greater influence on the curtailed life-expectancy, when compared against the impact of death by external causes. © 2011 Elsevier B.V.
Lopez R.,University of Aarhus
Oral health & preventive dentistry | Year: 2012
To assess whether adolescents with periodontitis presented with higher scores for non-psychotic psychosocial disorders than control subjects without periodontitis. A case control study (n = 160) nested in a well-defined adolescent population (n = 9,163) was performed using the 28-item Spanish version of the General Health Questionnaire. The inclusion criterion for being a case was a clinical attachment level of >= 3 mm in at least two teeth. Multiple logistic regression analyses were used to assess the association between periodontitis and psychosocial distress. The response rate was high and 94% of the participants answered all the items of the questionnaire. Similarly, the internal consistency of the instrument was high (Cronbach's = 0.91). The results of multiple logistic regression analyses, adjusted for age and gender, suggested an association between case status and higher total scoring for psychosocial distress (OR = 1.69). Among the four subdomains of the General Health Questionnaire, the dimensions 'somatic symptoms' and 'severe depression' appeared positively associated with periodontal case status, albeit not significantly. The findings of this study suggest that the association between periodontitis and dimensions of psychosocial distress can be documented early in life. This calls for awareness on the part of healthcare providers attending adolescents.
Meikle W.G.,U.S. Department of Agriculture |
Holst N.,University of Aarhus
Apidologie | Year: 2015
Monitoring physical variables associated with honeybee colonies, including weight, temperature, humidity, respiratory gases, vibration, sound, and forager traffic, in a continuous manner is becoming feasible for most researchers as the cost and size of electronic sensors decrease while their precision and capacity increase. Researchers have taken different approaches to collecting and analyzing the resulting datasets, with a view toward extracting information on colony behavior and phenology. The objective of this review is to examine critically the different kinds of data and data analyses, providing researchers with better-informed options for obtaining information on colony phenology in the field without disturbing the hive, and for combining information from different kinds of sensors to obtain a more complete picture of colony status. Wireless sensor networks and powering sensors are briefly discussed. © 2014, The Author(s).
Massignan P.,ICFO - Institute of Photonic Sciences |
Zaccanti M.,University of Florence |
Bruun G.M.,University of Aarhus
Reports on Progress in Physics | Year: 2014
In this review, we discuss the properties of a few impurity atoms immersed in a gas of ultracold fermions - the so-called Fermi polaron problem. On one hand, this many-body system is appealing because it can be described almost exactly with simple diagrammatic and/or variational theoretical approaches. On the other, it provides a quantitatively reliable insight into the phase diagram of strongly interacting population-imbalanced quantum mixtures. In particular, we show that the polaron problem can be applied to the study of itinerant ferromagnetism, a long-standing problem in quantum mechanics. © 2014 IOP Publishing Ltd.
Vilhelmsen L.B.,University of Aarhus |
Sholl D.S.,Georgia Institute of Technology
Journal of Physical Chemistry Letters | Year: 2012
Metal organic frameworks (MOFs) have experimentally been demonstrated to be capable of supporting isolated transition-metal clusters, but the stability of these clusters with respect to aggregation is unclear. In this letter we use a genetic algorithm together with density functional theory calculations to predict the structure of Pd clusters in UiO-66. The cluster sizes examined are far larger than those in any previous modeling studies of metal clusters in MOFs and allow us to test the hypothesis that the physically separated cavities in UiO-66 could stabilize isolated Pd clusters. Our calculations show that Pd clusters in UiO-66 are, at best, metastable and will aggregate into connected pore filling structures at equilibrium. © 2012 American Chemical Society.
Paludan S.R.,University of Aarhus
Microbiology and Molecular Biology Reviews | Year: 2015
The innate immune system provides early defense against infections and also plays a key role in monitoring alterations of homeostasis in the body. DNA is highly immunostimulatory, and recent advances in this field have led to the identification of the innate immune sensors responsible for the recognition of DNA as well as the downstream pathways that are activated. Moreover, information on how cells regulate DNA-driven immune responses to avoid excessive inflammation is now emerging. Finally, several reports have demonstrated how defects in DNA sensing, signaling, and regulation are associated with susceptibility to infections or inflammatory diseases in humans and model organisms. In this review, the current literature on DNA-stimulated innate immune activation is discussed, and important new questions facing this field are proposed. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
Nissen P.E.,University of Aarhus
Astronomy and Astrophysics | Year: 2013
Context. In some recent works, the C/O abundance ratio in high-metallicity stars with planets is found to vary by more than a factor of two, i.e. from ~0.4 to C/O ≥ 1. This has led to discussions about the existence of terrestrial planets with a carbon-dominated composition that is very different from the composition of the Earth. Aims. The mentioned C/O values were obtained by determining carbon abundances from high-excitation C i lines and oxygen abundances from the forbidden [O i] line at 6300 Å. This weak line is, however, strongly affected by a nickel blend at high metallicities. Aiming for more precise C/O ratios, oxygen abundances in this paper are derived from the high-excitation O i triplet at 7774 Å. Methods. The C i lines at 5052 and 5380 Å in HARPS spectra were applied to determine carbon abundances of 33 solar-type stars for which FEROS spectra are available for determining oxygen abundances from the O iλ7774 triplet. Differential abundances with respect to the Sun were derived from equivalent widths using MARCS model atmospheres. Non-LTE corrections were included, and the analysis was carried out with both spectroscopic and photometric estimates of stellar effective temperatures and surface gravities. Results. The results do not confirm the high C/O ratios previously found. C/O shows a tight, slightly increasing dependence on metallicity, i.e. from C/O â‰= 0.58 at [Fe/H] = 0.0 to C/O â‰= 0.70 at [Fe/H] = 0.4 with an rms scatter of only 0.06. Conclusions. Recent findings of C/O ratios higher than 0.8 in high-metallicity stars seem to be spurious due to statistical errors in estimating the strength of the weak [O i] line in the Ni i blended λ6300 feature. Assuming that the composition of a proto-planetary disk is the same as that of the host star, the C/O values found in this paper lend no support to the existence of carbon-rich planets. The small scatter of C/O among thin-disk stars suggests that the nucleosynthesis products of Type II supernovae and low- to intermediate-mass stars are well mixed in the interstellar medium. © ESO, 2013.
Sorensen L.K.,University of Aarhus
Journal of Analytical Toxicology | Year: 2012
A liquid chromatography-tandem mass spectrometry method, using pneumatically assisted electrospray ionization was developed for the determination of amiodarone, desethylamiodarone, propafenone, N-depropylpropafenone, 5-OH-propafenone, flecainide, and sotalol in human antemortem and postmortem whole blood. A mixture of methanol and acetonitrile was used to extract the samples, and the clear extracts obtained from the protein precipitation were injected directly onto an ethyl-linked phenyl LC column. The isotope dilution technique was applied for quantitative analysis. The relative intralaboratory reproducibility standard deviations were 5-9% at a concentration range of 1-5 mg/L and 9-12% at a concentration of 0.1 mg/L. The mean true recoveries were greater than 91% in the concentration range of 0.05-5 mg/L. The detection limits were in the range of 8-18 mg/L. © The Author . Published by Oxford University Press. All rights reserved.
Bossen C.,University of Aarhus
Computer Supported Cooperative Work | Year: 2011
Patient records are central, constitutive parts of health care and hospitals. Currently, substantial sums are being invested in making patient records electronic, in order to take advantage of IT's ability to quickly accumulate, compute, and propagate data to multiple sites, to enhance coordination of health care services and cooperation among staff, and make patient records immediately accessible to distributed actors. Investors also aim to increase health care services' accountability and integration, and improve quality and efficiency. This paper analyses a Danish national standard for electronic health records, on the basis of an application prototype test designed to that standard. The analysis shows that, inscribed in the standard is an ambition to increase the accountability of staff and health care services at the cost of increased work, loss of overview, and fragmentation of patient cases. Significantly, despite the standard having been conceived and developed in a process of co-construction involving clinicians, clinicians did not find it adequate for their work. This analysis argues this was the result of the model of work embedded in the standard coming from a stance external to practice. Subsequently, a flip-over effect occurred, in which the model of work became a model for work. Hence, this paper argues that co-construction processes should not only include users as representatives of a profession, but strive to produce experiences and knowledge intrinsic to practice. © Springer 2011.
Piet J.,University of Aarhus |
Wurtzen H.,Danish Cancer Society |
Zachariae R.,Aarhus University Hospital
Journal of Consulting and Clinical Psychology | Year: 2012
Objective: The use of mindfulness-based therapy (MBT) in oncology settings has become increasingly popular, and research in the field has rapidly expanded. The objective was by means of a systematic review and meta-analysis to evaluate the current evidence for the effect of MBT on symptoms of anxiety and depression in adult cancer patients and survivors. Method: Electronic databases were searched, and researchers were contacted for further relevant studies. Twenty-two independent studies with a total of 1,403 participants were included. Studies were coded for quality (range: 0-4), and overall effect size analyses were performed separately for nonrandomized studies (K = 13, n = 448) and randomized controlled trials (RCTs; K = 9, n = 955). Effect sizes were combined using the random-effects model. Results: In the aggregated sample of nonrandomized studies (average quality score: 0.5), MBT was associated with significantly reduced symptoms of anxiety and depression from pre-to posttreatment corresponding to moderate effect sizes (Hedges\'s g) of 0.60 and 0.42, respectively. The pooled controlled effect sizes (Hedges\'s g) of RCTs (average quality score: 2.9) were 0.37 for anxiety symptoms (p <.001) and 0.44 for symptoms of depression (p <.001). These effect sizes appeared robust. Furthermore, in RCTs, MBT significantly improved mindfulness skills (Hedges\'s g = 0.39). Conclusion: While the overall quality of existing clinical trials varies considerably, there appears to be some positive evidence from relatively high-quality RCTs to support the use of MBT for cancer patients and survivors with symptoms of anxiety and depression. © 2012 American Psychological Association.
Seeberg J.,University of Aarhus
Medical Anthropology Quarterly | Year: 2012
This article explores the impact of intensive competition within the pharmaceutical industry and among private providers on health care in an Indian city. In-depth interviewing and clinical observation were used over a period of 18 months. Private practitioners and chemists who provided regular services to inhabitants of a poor neighborhood in central Bhubaneswar were included. Fierce competition in private health in Odisha, India, reduced quality of care for the poor. The pharmaceutical industry exploited weak links in the health system to push drugs aggressively, including through illegal channels. The private health market is organized in small "network molecules" that maximize profit at the cost of health. The large private share of health care in India and stiff competition are detrimental for primary care in urban India. Free government services are urgently needed and a planned health insurance scheme should be linked to quality control measures. © 2012 by the American Anthropological Association.
Rasmussen J.A.,University of Aarhus
Journal of Physical Chemistry A | Year: 2013
Hydrogenation of carbonaceous materials is important within carbon-based electronics, hydrogen storage, and the catalytic formation of molecular hydrogen in space. This study presents a systematic investigation at the density functional theory level of the hydrogenation of all small closed-shell polycyclic aromatic hydrocarbons comprising up to four carbon hexagons plus pentacene, hexacene, and heptacene. Binding energies span from 0.43 to 2.70 eV. Two-fold coordinated carbon atoms are preferred as binding sites with binding energies from 1.06 to 2.70 eV. Analyzing the binding sites yields three different motifs each with a clear structural and electronic fingerprint explaining the ordering of the binding sites. © 2013 American Chemical Society.
Savoie B.,University of Aarhus
Annales Henri Poincare | Year: 2014
The purpose of this paper is to rigorously investigate the orbital magnetism of core electrons in three-dimensional crystalline ordered solids and in the zero-temperature regime. To achieve that, we consider a non-interacting Fermi gas subjected to an external periodic potential modeling the crystalline field within the tight-binding approximation (i.e., when the distance between two consecutive ions is large). For a fixed number of particles in the Wigner–Seitz cell and in the zero-temperature limit, we derive an asymptotic expansion for the bulk zero-field orbital susceptibility. We prove that the leading term is the superposition of the Larmor diamagnetic contribution, generated by the quadratic part of the Zeeman Hamiltonian, together with the ‘complete’ orbital Van Vleck paramagnetic contribution, generated by the linear part of the Zeeman Hamiltonian, and related to field-induced electronic transitions. © 2014, European Union.
Pritchard J.D.,Durham University |
Adams C.S.,Durham University |
Molmer K.,University of Aarhus
Physical Review Letters | Year: 2012
We consider three-level atoms driven by two resonant light fields in a ladder scheme where the upper level is a highly excited Rydberg state. We show that the dipole-dipole interactions between Rydberg excited atoms prevents the formation of single particle dark states and leads to strongly correlated photon pairs from atoms separated by distances large compared to the emission wavelength. For a pair of atoms, this enables realization of an efficient photon-pair source with on average one pair every 30μs. © 2012 American Physical Society.
Yuan Q.,University of Louisiana at Lafayette |
Hein S.,University of Aarhus |
Misra R.D.K.,University of Louisiana at Lafayette
Acta Biomaterialia | Year: 2010
The objective of the study is to describe a new approach of combining quantum dots technology with anti-cancer drug therapy. In this regard, we communicate the preliminary research on the synthesis of blue-light emitting ZnO quantum dots (QDs) combined with biodegradable chitosan (N-acetylglucosamine) for tumor-targeted drug delivery. The results presented here indicate that the proposed new generation of QDs loaded with anti-cancer agents and encapsulated with biocompatible polymer represent a potential platform to deliver tumor-targeted drugs and document the delivery process, if desired. Nontoxic water-dispersed ZnO QDs with long-term fluorescence stability were synthesized by a chemical hydrolysis method, encapsulated with chitosan and loaded with anti-cancer drug. Chitosan enhanced the stability of the QDs because of the hydrophilicity and cationic charge of chitosan. The study points toward the application of water-dispersed ZnO QDs with long-term fluorescence stability for design of new drug release carrier. © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Willnow T.E.,Max Delbruck Center for Molecular Medicine |
Nykjaer A.,University of Aarhus
Molecular and Cellular Endocrinology | Year: 2010
Steroid hormones are believed to enter cells solely by free diffusion through the plasma membrane. However, recent studies suggest the existence of cellular uptake pathways for carrier-bound steroids. Similar to the clearance of cholesterol via lipoproteins, these pathways involve the recognition of carrier proteins by endocytic receptors on the surface of target cells, followed by internalization and cellular delivery of the bound sterols. Here, we discuss the emerging concept that steroid hormones can selectively enter steroidogenic tissues by receptor-mediated endocytosis, and we discuss the implications of these uptake pathways for steroid hormone metabolism and action in vivo. © 2009 Elsevier Ireland Ltd. All rights reserved.
Christiansen O.,University of Aarhus
Physical Chemistry Chemical Physics | Year: 2012
This perspective addresses selected recent developments in the theoretical calculation of vibrational spectra, energies, wave functions and properties. The theoretical foundation and recently developed computational protocols for constructing hierarchies of vibrational Hamiltonian operators are reviewed. A many-mode second quantization (SQ) formulation is discussed prior to the discussion of anharmonic wave functions. Emphasis is put on vibrational self-consistent field (VSCF) based methods and in particular vibrational coupled cluster (VCC) theory. Other issues are also reviewed briefly, such as inclusion of thermal effects, response theoretical calculation of spectra, and the difficulty in treating dense spectra. © 2012 the Owner Societies.
Zelikin A.N.,University of Aarhus
ACS Nano | Year: 2010
Polymer films and coatings are among the popular and most successful tools to modulate surface properties of biomaterials, specifically tissue responses and fouling behavior. Over the past decade, a novel opportunity has been widely investigated, namely utility of surface coatings in surface-mediated drug delivery. In these applications, deposited polymer films act as both a coating to modulate surface properties and a reservoir for active therapeutic cargo. The field has recently accelerated beyond the proof-of-concept reports toward delivering practical solutions and established technologies for biomedical applications. This review briefly summarizes the recent successes of polymer thin films, specifically those constructed by sequential polymer deposition technique, in surface-mediated drug delivery. © 2010 American Chemical Society.
Bruun G.M.,University of Aarhus |
Nelson D.R.,Harvard University
Physical Review B - Condensed Matter and Materials Physics | Year: 2014
Recent advances in cold atom experimentation suggest that studies of quantum two-dimensional melting of dipolar molecules, with dipoles aligned perpendicular to ordering plane, may be on the horizon. An intriguing aspect of this problem is that two-dimensional classical aligned dipoles (already studied in great detail in soft matter experiments on magnetic colloids) are known to melt via a two-stage process, with an intermediate hexatic phase separating the usual crystal and isotropic fluid phases. We estimate here the effect of quantum fluctuations on this hexatic phase, for both dipolar systems and charged Wigner crystals. Our approximate phase diagrams rely on a pair of Lindemann criteria, suitably adapted to deal with the effects of thermal fluctuations in two dimensions. As part of our analysis, we determine the phonon spectra of quantum particles on a triangular lattice interacting with repulsive 1/r3 and 1/r potentials. A large softening of the transverse and longitudinal phonon frequencies, due to both lattice effects and quantum fluctuations, plays a significant role in our analysis. The hexatic phase is predicted to survive down to very low temperatures. © 2014 American Physical Society.
Heymann M.,University of Aarhus
Scientia canadensis | Year: 2010
This paper explores a vacant spot in the Cold War history of science: the development of research activities in the physical environmental sciences and in nuclear science and technology in Greenland. In the post-war period, scientific exploration of the polar areas became a strategically important element in American and Soviet defence policy. Particularly geophysical fields like meteorology, geology, seismology, oceanography, and others profited greatly from military interest. While Denmark maintained formal sovereignty over Greenland, research activities were strongly dominated by U.S. military interests. This paper sets out to summarize the limited current state of knowledge about activities in the environmental physical sciences in Greenland and their entanglement with military, geopolitical, and colonial interests of both the USA and Denmark. We describe geophysical research in the Cold War in Greenland as a multidimensional colonial endeavour. In a period of decolonization after World War II, Greenland, being a Danish colony, became additionally colonized by the American military. Concurrently, in a period of emerging scientific internationalism, the U.S. military "colonized" geophysical research in the Arctic, which increasingly became subject to military directions, culture, and rules.
Krueger J.,Copenhagen University |
Michael J.,University of Aarhus
Frontiers in Human Neuroscience | Year: 2012
Social cognition researchers have become increasingly interested in the ways that behavioral, physiological, and neural coupling facilitate social interaction and interpersonal understanding. We distinguish two ways of conceptualizing the role of such coupling processes in social cognition: strong and moderate interactionism. According to strong interactionism (SI), low-level coupling processes are alternatives to higher-level individual cognitive processes; the former at least sometimes render the latter superfluous. Moderate interactionism (MI) on the other hand, is an integrative approach. Its guiding assumption is that higher-level cognitive processes are likely to have been shaped by the need to coordinate, modulate, and extract information from low-level coupling processes. In this paper, we present a case study on Möbius Syndrome (MS) in order to contrast SI and MI. We show how MS-a form of congenital bilateral facial paralysis-can be a fruitful source of insight for research exploring the relation between high-level cognition and low-level coupling. Lacking a capacity for facial expression, individuals with MS are deprived of a primary channel for gestural coupling. According to SI, they lack an essential enabling feature for social interaction and interpersonal understanding more generally and thus ought to exhibit severe deficits in these areas. We challenge SI's prediction and show how MS cases offer compelling reasons for instead adopting MI's pluralistic model of social interaction and interpersonal understanding. We conclude that investigations of coupling processes within social interaction should inform rather than marginalize or eliminate investigation of higher-level individual cognition. © 2012 Krueger and Michael.
Kjeldsen K.H.,University of Aarhus
INFOR | Year: 2011
This article provides a classification scheme for ship routing and scheduling problems in liner shipping in line with the current and future operational conditions of the liner shipping industry. Based on the classification, the literature is divided into groups whose main characteristics are described. The literature within each group is reviewed, much of it for the first time.
Topping C.J.,University of Aarhus
Ecological Engineering | Year: 2011
Organic farming has often been suggested as a way of increasing biodiversity in agricultural landscapes, but literature reports a variable success. The drivers in play are multi-factorial and include the particular species groups under consideration, the precise form of organic management, the landscape structural and management context, the area and scale considered, and the historical context. Here ALMaSS, a comprehensive agent-based model simulation system, was used to produce an assessment of the impact of organic and conventional farm types, landscape structure, and management context for six common agricultural wildlife species. ALMaSS outputs can be expressed as a simple index of relative change in abundance and distribution, allowing easy comparison between scenarios. Results indicate that organic farming generally had a beneficial effect, but the degree was variable with all factors considered and there were strong interactions between factors. Targeted managements provided much greater impacts than changes in farm types. Predictions of biodiversity impacts depended on precise inputs, underlying both the view of this system as being complex, and the necessity for detailed knowledge. However, this combination of detailed modelling platform with a simple index of impact provides an easily interpreted method for objective evaluation of impacts of potential policy scenarios. © 2011 Elsevier B.V.
Doherty J.,Flinders University |
Christensen S.,University of Aarhus
Water Resources Research | Year: 2011
Modern environmental management and decision-making is based on the use of increasingly complex numerical models. Such models have the advantage of allowing representation of complex processes and heterogeneous system property distributions inasmuch as these are understood at any particular study site. The latter are often represented stochastically, this reflecting knowledge of the character of system heterogeneity at the same time as it reflects a lack of knowledge of its spatial details. Unfortunately, however, complex models are often difficult to calibrate because of their long run times and sometimes questionable numerical stability. Analysis of predictive uncertainty is also a difficult undertaking when using models such as these. Such analysis must reflect a lack of knowledge of spatial hydraulic property details. At the same time, it must be subject to constraints on the spatial variability of these details born of the necessity for model outputs to replicate observations of historical system behavior. In contrast, the rapid run times and general numerical reliability of simple models often promulgates good calibration and ready implementation of sophisticated methods of calibration-constrained uncertainty analysis. Unfortunately, however, many system and process details on which uncertainty may depend are, by design, omitted from simple models. This can lead to underestimation of the uncertainty associated with many predictions of management interest. The present paper proposes a methodology that attempts to overcome the problems associated with complex models on the one hand and simple models on the other hand, while allowing access to the benefits each of them offers. It provides a theoretical analysis of the simplification process from a subspace point of view, this yielding insights into the costs of model simplification, and into how some of these costs may be reduced. It then describes a methodology for paired model usage through which predictive bias of a simplified model can be detected and corrected, and postcalibration predictive uncertainty can be quantified. The methodology is demonstrated using a synthetic example based on groundwater modeling environments commonly encountered in northern Europe and North America. © 2011 by the American Geophysical Union.
Britz D.,University of Aarhus
Electrochimica Acta | Year: 2011
C. Amatore and co-workers share views on the adaptive grids that are employed in electrochemical simulations. The software that are often used by electrochemists for solving partial differential equations, such as that of COMSOL Multiphysics, ElchSoft (producing DigiElch) and PDE Solutions (producing FlexPDE), and the freely available EChem++ use adaptive grid techniques. Amatore focuses on the adaptive gridding to handle moving fronts in the solution and the use of either gradients or (more recently) error estimates as the criterion. The use of error estimates or related quantities appears to be the best approach to grid adaptation.
Pedersen C.B.,University of Aarhus
Scandinavian Journal of Public Health | Year: 2011
Introduction: The Danish Civil Registration System (CRS) was established in 1968, and all persons alive and living in Denmark were registered for administrative use. Content: CRS includes individual information on the unique personal identification number, name, gender, date of birth, place of birth, citizenship, identity of parents and continuously updated information on vital status, place of residence and spouses. Validity and coverage: Since 1968, CRS has recorded current and historical information on all persons living in Denmark. Among persons born in Denmark in 1960 or later it contains complete information on maternal identity. For women born in Denmark in April 1935 or later it contains complete information on all their children. CRS contains complete information on immigrations and emigrations from 1969 onwards, permanent residence in a Danish municipality from 1971 onwards, and full address in Denmark from 1977 onwards. Conclusion: CRS in connection with other registers and biobanks will continue to provide the basis for significant knowledge relevant to the aetiological understanding and possible prevention of human diseases. © 2010 the Nordic Societies of Public Health.
Molmer K.,University of Aarhus
Physical Review Letters | Year: 2015
Using a quantum circuit model we derive the maximal ability to distinguish which of several candidate Hamiltonians describe an open quantum system. This theory, in particular, provides the maximum information retrievable from continuous quantum measurement records, available when a quantum system is perturbatively coupled to a broadband quantized environment. © 2015 American Physical Society.
Toft T.,University of Aarhus
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011
The classic problem in the field of secure computation is Yao's millionaires' problem; we consider two new protocols solving a variation of this: a number of parties, P 1,⋯, P n , securely hold two ℓ-bit values, x and y - e.g. x and y could be encrypted or secret shared. They wish to obtain a bit stating whether x is greater than y using only secure arithmetic; this should be done without revealing any information, even the output should remain secret. The present setting is special in the sense that it is assumed that two specific parties, referred to as Alice and Bob, are non-colluding. Though this assumption is not satisfied in general, it clearly is for the main example of this work: two-party computation based on Paillier encryption. The first solution requires O(log(ℓ)(κ+loglog(ℓ))) secure arithmetic operations in O(log(ℓ)) rounds, where κ is a correctness parameter. The second solution requires only a constant number of rounds, but increases complexity to O(√ℓ(κ+log(ℓ))) arithmetic operations. For the motivating setting, each arithmetic operation requires a constant number of Paillier encryptions to be exchanged between Alice and Bob. This implies that both solutions require only a sub-linear number of invocations (in the bit-length, ℓ) of the cryptographic primitives. This does not imply sub-linear communication, though, as the size of each encryption transmitted is more than ℓ bits. © 2011 International Association for Cryptologic Research.
Lan-Pidhainy X.,Cornell University |
Nohr E.A.,University of Aarhus |
Rasmussen K.M.,Cornell University
American Journal of Clinical Nutrition | Year: 2013
Background: In Danish data, the tradeoffs between mother and infant in the risks of adverse pregnancy outcomes were reached at lower gestational weight gain (GWG) among multiparous than among primiparous women. It is unknown whether the same difference exists among American women. Objective: The objective was to determine whether these tradeoffs also differ by parity among women in a contemporary American birth cohort. Design: Data from 822 primiparous and 2055 multiparous American women who participated in the Infant Feeding Practices Study II (2005-2007), a national cohort study, were analyzed. Their selfreported GWG was divided into 4 categories (#10, .10 to ,15, 15 to ,20, and S20 kg). GWG-specific absolute adjusted risks for emergency cesarean delivery, birth of a small-for-gestational-age (SGA) or large-for-gestational-age (LGA) infant, and postpartum weight retention at±mo were estimated by multiple logistic regression analyses for women in 3 categories of prepregnancy body mass index. Results: Primiparous women gained more weight during pregnancy than did multiparous women (mean±SD: 15.9±6.9 compared with 13.5±6.2 kg; P < 0.0001). The absolute adjusted risk of postpartum weight retention rose steeply with increasing GWG among both primiparous and multiparous women. The risk of emergency cesarean delivery and of delivering LGA infants increased with increasing GWG only among multiparous women. The risk of SGA tended to decrease with increasing GWG in both parity groups. Conclusion: These findings extend the concept of a lower optimal GWG among multiparous than primiparous women to American women. © 2013 American Society for Nutrition.
Bonefeld-Jorgensen E.C.,University of Aarhus
Environmental health : a global access science source | Year: 2014
We have previously reported that chemicals belonging to the persistent organic pollutants (POPs) such as perfluorinated compounds (PFAS) and polychlorinated biphenyls (PCBs) are risk factors in Breast Cancer (BC) development in Greenlandic Inuit women. The present case-control study aimed to investigate the main effect of polymorphisms in genes involved in xenobiotic metabolism and estrogen biosynthesis, CYP1A1, CYP1B1, COMT and CYP17, CYP19 and the BRCA1 founder mutation in relation to BC risk and to explore possible interactions between the gene polymorphisms and serum POP levels on BC risk in Greenlandic Inuit women. The study population consisted of 31 BC cases and 115 matched controls, with information on serum levels of POPs. Genotyping was conducted for CYP1A1 (Ile462Val; rs1048943), CYP1B1 (Leu432Val; rs1056836), COMT (Val158Met; rs4680), CYP17A1 (A1> A2; rs743572); CYP19A1 (C> T; rs10046) and CYP19A1 ((TTTA)n repeats) polymorphisms and BRCA1 founder mutation using TaqMan allelic discrimination method and polymerase chain reaction based restriction fragment length polymorphism. The χ2 -test was used to compare categorical variables between cases and controls and the odds ratios were estimated by unconditional logistic regression models. We found an independent association of CYP1A1 (Val) and CYP17 (A1) with BC risk.Furthermore, an increased BC risk was observed for women with high serum levels of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) and carriers of at least: one CYP1A1 variant Val allele; one variant COMT Met allele; or the common CYP17 A1 allele. No combined effects were seen between PFAS exposure and CYP1B1 and CYP19 polymorphisms. The risk of BC was not found significantly associated with exposure to PCBs and OCPs, regardless of genotype for all investigated SNPs. The frequency of the Greenlandic founder mutation in BRCA1 was as expected higher in cases than in controls. The BRCA1 founder mutation and polymorphisms in CYP1A1 (Val) and CYP17 (A1) can increase the BC risk among Inuit women and the risk increases with higher serum levels of PFOS and PFOA. Serum PFAS levels were a consistent risk factor of BC, but inter-individual polymorphic differences might cause variations in sensitivity to the PFAS/POP exposure.
Knudsen M.,University of Aarhus
Human genomics | Year: 2010
The CATH database provides hierarchical classification of protein domains based on their folding patterns. Domains are obtained from protein structures deposited in the Protein Data Bank and both domain identification and subsequent classification use manual as well as automated procedures. The accompanying website (www.cathdb.info) provides an easy-to-use entry to the classification, allowing for both browsing and downloading of data. Here, we give a brief review of the database, its corresponding website and some related tools.
Schmidt L.M.,Mental Health Center Sct Hans |
Hesse M.,University of Aarhus |
Lykke J.,Mental Health Center Sct Hans
Schizophrenia Research | Year: 2011
Background: This follow-up study compared patients with schizophrenia with co-occurring substance use disorder to patients with schizophrenia and no substance use disorder. Aims: To investigate the prognostic significance of the effects of substance use disorders on the course of schizophrenia. Method: Patients with schizophrenia and co-occurring substance use disorder (n = 107), and patients with schizophrenia only (n = 119) were followed over a 15-year period through the use of national hospitalization registers, data for time and cause of death, and data for homelessness or institutionalization. Results: The median length of psychiatric hospitalization was 12. days for a patient with dual diagnosis, and 21. days for patients with schizophrenia only. Patients with dual diagnosis displayed a significantly elevated usage of all types of hospital contacts except inpatient treatment for non-psychiatric disorders. In three types of hospital contacts, patients with co-occurring substance use had approximately two to three times as many hospitalizations as did patients with schizophrenia only. Rates for homelessness and institutionalization were similar in both groups. Patients with a dual diagnosis were also significantly more at risk of dying during follow-up than were patients with schizophrenia only. Conclusions: The findings suggest that the long-term course of schizophrenia is considerably more severe in patients who have a dual diagnosis compared to patients with schizophrenia only Substance use disorders have a substantial impact on the hospitalization rates of patients with schizophrenia, as well as on life expectancy. Patients with co-morbid substance abuse are more likely to be admitted for treatment during a given year although they have briefer contact with treatment. © 2011 Elsevier B.V.
Bergfur J.,Linkoping University |
Friberg N.,University of Aarhus
Fungal Ecology | Year: 2012
We examined the effects of temperature, nutrients and substrata on microbial respiration rates. Leaves of alder and oak were incubated in a natural stream. Leaf discs were incubated in antibiotics to manipulate the ratio of fungi to bacteria with three treatments: antifungal, antibacterial, and combined antifungal and antibacterial treatment in addition to controls. Discs were subsequently incubated in different nutrient set-ups and temperature regimes. Significant effects of temperature, nutrients, microbial treatment and leaf type on respiration rates were found. However, temperature did not significantly add to the effect of eutrophication on microbial respiration rates. A stronger effect of temperature on fungal mediated respiration than on bacterial mediated respiration was found. In streams where leaf litter constitutes the main energy source, fungi constitute the dominant microbial decomposer. Our results indicate that increased temperature due to global warming might have serious implications for ecosystem functioning when leaf litter constitutes the main energy source. © 2011 Elsevier Ltd and The British Mycological Society.
Svenning J.-C.,University of Aarhus
Ecography | Year: 2014
The International Biogeography Society's biennial conferences are renown for being highly interdisciplinary and inspiring meetings. Biogeography is by its nature a holistic and interdisciplinary field and the conferences bring together biologists from a broad range of fields, e.g. experimental ecologists, historical biogeographers, evolutionary biologists, ecological modelers, conservation biologists, and paleobiologists, and covering essentially all types of organisms and ecosystems. The different backgrounds and perspectives combined with shared interests in terms of the basic research questions offer fertile grounds for developing new ideas. This was also the case for the 6th International Conference of the International Biogeography Society took place in Miami, Florida in January 2013. Ecography provided economic support, acting as a sponsor. In addition, Ecography was the officially designated journal for publishing some of the many exciting talks and posters presented at the conference. All of the papers in this special issue of Ecography arose from the IBS conference and reflect its combined high diversity in backgrounds and perspectives and high congruence in research questions. The papers have all been subject to external peer review, subsequent revision, and final editorial decisions of acceptance or rejection. © 2014 The Author.
Rahmani A.,University of Aarhus
The Journal of heart valve disease | Year: 2013
Attention towards the optimization of mitral valve repair methods is increasing. Patch augmentation is one strategy used to treat functional ischemic mitral regurgitation (FIMR). The study aim was to investigate the force balance changes in specific chordae tendineae emanating from the posterior papillary muscle in a FIMR-simulated valve, following posterior leaflet patch augmentation. Mitral valves were obtained from 12 pigs (body weight 80 kg). An in vitro test set-up simulating the left ventricle was used to hold the valves. The left ventricular pressure was regulated with water to simulate different static pressures during valve closure. A standardized oval pericardial patch (17 x 29 mm) was introduced into the posterior leaflet from mid P2 to the end of the P3 scallop. Dedicated miniature transducers were used to record the forces exerted on the chordae tendineae. Data were acquired before and after 12 mm posterior and 5 mm apical posterior papillary muscle displacement to simulate the effect from one of the main contributors of FIMR, before and after patch augmentation. The effect of displacing the posterior papillary muscle induced tethering on the intermediate chordae tendineae to the posterior leaflet, and resulted in a 39.8% force increase (p = 0.014). Posterior leaflet patch augmentation of the FIMR valve induced a 31.1% force decrease (p = 0.007). There was no difference in force between the healthy and the repaired valve simulations (p = 0.773). Posterior leaflet patch augmentation significantly reduced the forces exerted on the intermediate chordae tendineae from the posterior papillary muscle following FIMR simulation. As changes in chordal tension lead to a redistribution of the total stress exerted on the valve, patch augmentation may have an adverse long-term influence on mitral valve function and remodeling.
Faurby S.,University of California at Los Angeles |
Faurby S.,University of Aarhus |
Barber P.H.,University of California at Los Angeles
Molecular Ecology | Year: 2012
Increasing dispersal duration should result in increasing dispersal distance, facilitating higher gene flow among populations. As such, it has long been predicted that genetic structure (e.g. F ST) among populations of marine species should be strongly correlated with pelagic larval duration (PLD). However, previous studies have repeatedly shown a surprisingly poor correspondence. This result has been frequently interpreted as evidence for larval behaviours or physical oceanographic processes that result in larvae failing to reach their dispersal potential, or error inherent in estimating PLD and F ST. This study employed a computer modelling approach to explore the impacts of various uncertainties on the correlation between measures of genetic differentiation such as F ST and PLD. Results indicate that variation resulting from PLD estimation error had minor impacts on the correlation between genetic structure and PLD. However, variation in effective population size between species, errors in F ST estimation and non-equilibrium F ST values all had major impacts, resulting in dramatically weaker correlations between PLD and F ST. These results suggest that poor correlations between PLD and F ST may result from variation and uncertainty in the terms associated with the calculation of F ST values. As such, PLD may be a much stronger determinant of realized larval dispersal than suggested by the weak-to-moderate correlations between PLD and F ST reported in empirical studies. © 2012 Blackwell Publishing Ltd.
Petersen S.O.,University of Aarhus
European Journal of Soil Science | Year: 2014
Soil-atmosphere fluxes of trace gases such as methane (CH4) and nitrous oxide (N2O) are determined by complex interactions between biological activity and soil conditions. Soil gas concentration profiles may, in combination with other information about soil conditions, help us to understand emission controls. This paper describes a simple and robust diffusion probe for soil gas sampling as part of flux monitoring programmes. It can be deployed with minimum disturbance of in-situ conditions, and also at sites with a high or fluctuating water table. Separate probes are used for each sampling depth, in this study ranging from 5 to 100 cm. The probe has a 10-ml diffusion cell with a 3-mm diameter opening covered by a 0.5-mm silicone membrane. At sampling the diffusion cell is flushed with 10 ml N2 containing 50 μl l-1 ethylene (C2H4) as a tracer; tracer recovery is used to calculate sample concentrations. Ethylene is immediately removed by flushing with unamended N2. Equations are presented to correct for dead volumes of connecting tubing and valves. Laboratory tests evaluated recovery of CH4, N2O and carbon dioxide (CO2), removal of C2H4 and equilibration of CH4, N2O and CO2 in air and water. Field tests on peat soils used for grazing showed soil gas concentrations of CH4 and N2O as influenced by topography, site conditions and season. The applicability of the diffusion probe for trace gas monitoring is discussed. © 2014 British Society of Soil Science.
de Groot J.I.M.,Bournemouth University |
Schuitema G.,University of Aarhus
Environmental Science and Policy | Year: 2012
This study examined how policy characteristics (i.e. push versus pull measure and high versus low cost behaviour targeted) and social norms (i.e. strong versus weak social norms) influence the acceptability of environmental policies. Results of a mixed 2 × 2 × 2 subjects design among 123 participants showed that pull measures were evaluated as more acceptable than push measures; and when environmental policies targeted high cost behaviour, participants evaluated policies as less acceptable than when low cost behaviour was targeted. Moreover, a main effect for social norms was found: when it was indicated that a minority instead of a majority of the public supported a policy, acceptability was lower. The results showed two interaction effects. That is, push measures were particularly perceived as unacceptable when: (1) they targeted high cost behaviour, and (2) when a weak social norm was experienced. When a push measure targeted low cost behaviour or when it was clear that the majority of people supported this policy, the environmental policy was almost as acceptable as pull measures. The results imply that push measures should be presented in the correct way to minimise public opposition as to make the unpopular popular. © 2012 Elsevier Ltd.