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Stockholm, Sweden

Stockholm University is the state university of Stockholm, Sweden. Stockholm University has two scientific fields: the natural science and the humanities/social science. With over 70,000 students at four different faculties, law, humanities, the mathematical and natural science, it is one of the largest universities in Scandinavia. The institution is regarded as one of the top 100 universities in the world by both the Academic Ranking of World Universities and the Times Higher Education World University Rankings - whereas, in the QS World University Rankings, the SU is among the 200 universities in the world. Stockholm University was granted university status in 1960, making it the fourth oldest Swedish university. Stockholm University's primary mission is to provide education and high quality research for the betterment of the Swedish community. Wikipedia.

Olefeldt D.,University of Guelph | Turetsky M.R.,University of Guelph | Crill P.M.,University of Stockholm | Mcguire A.D.,U.S. Geological Survey
Global Change Biology | Year: 2013

Methane (CH4) emissions from the northern high-latitude region represent potentially significant biogeochemical feedbacks to the climate system. We compiled a database of growing-season CH4 emissions from terrestrial ecosystems located across permafrost zones, including 303 sites described in 65 studies. Data on environmental and physical variables, including permafrost conditions, were used to assess controls on CH4 emissions. Water table position, soil temperature, and vegetation composition strongly influenced emissions and had interacting effects. Sites with a dense sedge cover had higher emissions than other sites at comparable water table positions, and this was an effect that was more pronounced at low soil temperatures. Sensitivity analysis suggested that CH4 emissions from ecosystems where the water table on average is at or above the soil surface (wet tundra, fen underlain by permafrost, and littoral ecosystems) are more sensitive to variability in soil temperature than drier ecosystems (palsa dry tundra, bog, and fen), whereas the latter ecosystems conversely are relatively more sensitive to changes of the water table position. Sites with near-surface permafrost had lower CH4 fluxes than sites without permafrost at comparable water table positions, a difference that was explained by lower soil temperatures. Neither the active layer depth nor the organic soil layer depth was related to CH4 emissions. Permafrost thaw in lowland regions is often associated with increased soil moisture, higher soil temperatures, and increased sedge cover. In our database, lowland thermokarst sites generally had higher emissions than adjacent sites with intact permafrost, but emissions from thermokarst sites were not statistically higher than emissions from permafrost-free sites with comparable environmental conditions. Overall, these results suggest that future changes to terrestrial high-latitude CH4 emissions will be more proximately related to changes in moisture, soil temperature, and vegetation composition than to increased availability of organic matter following permafrost thaw. © 2012 Blackwell Publishing Ltd.

Heiwe S.,Karolinska Institutet | Heiwe S.,Karolinska University Hospital | Jacobson S.H.,University of Stockholm
American Journal of Kidney Diseases | Year: 2014

Background Whether exercise can affect health outcomes in people with chronic kidney disease (CKD) and what the optimal exercise strategies are for patients with CKD remain uncertain. Study Design Systematic review and meta-analysis of randomized controlled trials. Setting & Population Adults with CKD stages 2-5, dialysis therapy, or a kidney transplant. Selection Criteria for Studies Trials evaluating regular exercise training outcomes identified by searches in Cochrane CENTRAL, MEDLINE, EMBASE, CINAHL, Web of Science, BIOSIS, PEDro, AMED, AgeLine, PsycINFO, and KoreaMed, without language restriction. Intervention Regular exercise training for at least 8 weeks. Outcomes Vary by study but could include aerobic capacity, muscular functioning, cardiovascular function, walking capacity, and health-related quality of life. Treatment effects were summarized as standardized difference with 95% CIs using random-effects meta-analysis. Results 41 trials (928 participants) comparing exercise training with sham exercise or no exercise were included; overall, improved aerobic capacity, muscular functioning, cardiovascular function, walking capacity, and health-related quality of life were associated with various exercise interventions, although the preponderance of data were for dialysis patients and used aerobic exercise programs. Limitations Unclear or high risk of bias in 32% of the trials, few trial data concerning resistance training, and limited data for several important outcomes. Conclusions Regular exercise training generally is associated with improved health outcomes in individuals with CKD. Correctly designed exercise rehabilitation may be an effective part of care for adults with CKD. Future studies should examine longer term outcomes and strategies to translate exercise done in a supervised setting to the home setting for broader applicability. © 2014 by the National Kidney Foundation, Inc.

The 'choice' of whether to enter diapause or to develop directly has profound effects on the life histories of insects, and may thus have cascading consequences such as seasonal morphs and other less obvious forms of seasonal plasticity. Present knowledge of the control of diapause and seasonal morphs at the physiological and molecular levels is briefly reviewed. Examples, mainly derived from personal research (primarily on butterflies), are given as a starting point with the aim of outlining areas of research that are still poorly understood. These include: the role of the direction of change in photoperiod; the role of factors such as temperature and diet in modifying the photoperiodic responses; and the role of sex, parental effects and sex linkage on photoperiodic control. More generally, there is still a limited understanding of how external cues and physiological pathways regulating various traits are interconnected via gene action to form a co-adapted complete phenotype that is adaptive in the wild despite environmental fluctuation and change. © 2013 The Royal Entomological Society.

Kapyla P.J.,University of Helsinki | Mantere M.J.,University of Helsinki | Brandenburg A.,University of Stockholm | Brandenburg A.,Albanova University Center
Astrophysical Journal Letters | Year: 2012

We report on simulations of turbulent, rotating, stratified, magnetohydrodynamic convection in spherical wedge geometry. An initially small-scale, random, weak-amplitude magnetic field is amplified by several orders of magnitude in the course of the simulation to form oscillatory large-scale fields in the saturated state of the dynamo. The differential rotation is solar-like (fast equator), but neither coherent meridional poleward circulation nor near-surface shear layer develop in these runs. In addition to a poleward branch of magnetic activity beyond 50° latitude, we find for the first time a pronounced equatorward branch at around 20° latitude, reminiscent of the solar cycle. © 2012. The American Astronomical Society. All rights reserved.

Wheat C.W.,University of Helsinki | Wheat C.W.,University of Stockholm | Wahlberg N.,University of Turku
Systematic Biology | Year: 2013

The timing of the origin of arthropods in relation to the Cambrian explosion is still controversial, as are the timing of other arthropod macroevolutionary events such as the colonization of land and the evolution of flight. Here we assess the power of a phylogenomic approach to shed light on these major events in the evolutionary history of life on earth. Analyzing a large phylogenomic dataset (122 taxa, 62 genes) with a Bayesian-relaxed molecular clock, we simultaneously reconstructed the phylogenetic relationships and the absolute times of divergences among the arthropods. Simulations were used to test whether our analysis could distinguish between alternative Cambrian explosion scenarios with increasing levels of autocorrelated rate variation. Our analyses support previous phylogenomic hypotheses and simulations indicate a Precambrian origin of the arthropods. Our results provide insights into the 3 independent colonizations of land by arthropods and suggest that evolution of insect wings happened much earlier than the fossil record indicates, with flight evolving during a period of increasing oxygen levels and impressively large forests. These and other findings provide a foundation for macroevolutionary and comparative genomic study of Arthropoda. © 2012 The Author(s).

Rocha L.E.C.,Umea University | Liljeros F.,University of Stockholm | Holme P.,Umea University | Holme P.,Sungkyunkwan University
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010

Like many other social phenomena, prostitution is increasingly coordinated over the Internet. The online behavior affects the offline activity; the reverse is also true. We investigated the reported sexual contacts between 6,624 anonymous escorts and 10,106 sex buyers extracted from an online community from its beginning and six years on. These sexual encounters were also graded and categorized (in terms of the type of sexual activities performed) by the buyers. From the temporal, bipartite network of posts, we found a full feedback loop in which high grades on previous posts affect the future commercial success of the sex worker, and vice versa. We also found a peculiar growth pattern in which the turnover of community members and sex workers causes a sublinear preferential attachment. There is, moreover, a strong geographic influence on network structure-the network is geographically clustered but still close to connected, the contacts consistent with the inverse-square law observed in trading patterns. We also found that the number of sellers scales sublinearly with city size, so this type of prostitution does not, comparatively speaking, benefit much from an increasing concentration of people.

Friberg M.,University of Stockholm
Ecology | Year: 2010

Phenotypic plasticity can be a passive response to fluctuating environmental conditions or an active and presumably adaptive (evolved) response selected for in different environments. Here we ask if the larval decision to enter diapause when reared on a host plant associated with a colder habitat is an active or a passive response to host-plant quality or suitability. We compare plasticity in larval propensity to enter diapause of the habitat generalist butterfly Leptidea sinapis and the meadow specialist Leptidea reali in a range of temperatures and long day length on a forest plant, Lathyrus linifolius, and a meadowassociated plant, Lathyrus pratensis. The warmer meadow habitat promotes direct development whereas the colder forest habitat is conducive to diapause. Larvae of L. sinapis had a higher propensity to enter diapause when reared on the forest plant L. linifolius across all temperatures. Conversely, the propensity of L. reali to enter diapause was consistently lower and did not differ between host plants. Larval growth rates were similar between and within butterfly species and between host plants. Hence, we conclude that larval pathway decision-making in L. sinapis is an active response mediated by information from their host plants. © 2010 by the Ecological Society of America.

Huber M.,Purdue University | Caballero R.,University of Stockholm
Climate of the Past | Year: 2011

The early Eocene "equable climate problem", i.e. warm extratropical annual mean and above-freezing winter temperatures evidenced by proxy records, has remained as one of the great unsolved problems in paleoclimate. Recent progress in modeling and in paleoclimate proxy development provides an opportunity to revisit this problem to ascertain if the current generation of models can reproduce the past climate features without extensive modification. Here we have compiled early Eocene terrestrial temperature data and compared with climate model results using a consistent and rigorous methodology. We test the hypothesis that equable climates can be explained simply as a response to increased greenhouse gas forcing within the framework of the atmospheric component of the Community Climate System Model (version 3), a climate model in common use for predicting future climate change. We find that, with suitably large radiative forcing, the model and data are in general agreement for annual mean and cold month mean temperatures, and that the pattern of high latitude amplification recorded by proxies can be largely, but not perfectly, reproduced. © 2010 Author(s).

Dinitrogen (N2)-fixation by cyanobacteria living in symbiosis with pleurocarpous feather mosses (for example, Pleurozium schreberi and Hylocomium splendens) represents the main pathway of biological N input into N-depleted boreal forests. Little is known about the role of the cyanobacterial community in contributing to the observed temporal variability of N2-fixation. Using specific nifH primers targeting four major cyanobacterial clusters and quantitative PCR, we investigated how community composition, abundance and nifH expression varied by moss species and over the growing seasons. We evaluated N2-fixation rates across nine forest sites in June and September and explored the abundance and nifH expression of individual cyanobacterial clusters when N2-fixation is highest. Our results showed temporal and host-dependent variations of cyanobacterial community composition, nifH gene abundance and expression. N2-fixation was higher in September than June for both moss species, explained by higher nifH gene expression of individual clusters rather than higher nifH gene abundance or differences in cyanobacterial community composition. In most cases, ‘Stigonema cluster’ made up less than 29% of the total cyanobacterial community, but accounted for the majority of nifH gene expression (82–94% of total nifH expression), irrespective of sampling date or moss species. Stepwise multiple regressions showed temporal variations in N2-fixation being greatly explained by variations in nifH expression of the ‘Stigonema cluster’. These results suggest that Stigonema is potentially the most influential N2-fixer in symbiosis with boreal forest feather mosses. © 2016 International Society for Microbial Ecology

Nakosai S.,University of Tokyo | Budich J.C.,University of Stockholm | Tanaka Y.,Nagoya University | Trauzettel B.,University of Wurzburg | And 2 more authors.
Physical Review Letters | Year: 2013

We study theoretically the proximity effect of a one-dimensional metallic quantum wire (in the absence of spin-orbit interaction) lying on top of an unconventional superconductor. Three different material classes are considered as a substrate: (i) a chiral superconductor in class D with broken time-reversal symmetry and a class DIII superconductor (ii) with and (iii) without a nontrivial Z2 number. Interestingly, we find degenerate zero energy Majorana bound states at both ends of the wire for all three cases. They are unstable against spin-orbit interaction in case (i), while they are topologically protected by time-reversal symmetry in cases (ii) and (iii). Remarkably, we show that nonlocal spin correlations between the two ends of the wire can be simply controlled by a gate potential in our setup. © 2013 American Physical Society.

Brandeker A.,University of Stockholm
Astrophysical Journal | Year: 2011

Ever since the discovery of the edge-on circumstellar (CS) disk around β Pictoris, a standing question has been why the gas observed against the star in absorption is not rapidly expelled by the strong radiation pressure from the star. A solution to the puzzle has been suggested to be that the neutral elements that experience the radiation force also are rapidly ionized, and so are only able to accelerate to an average limiting velocity v ion. Once ionized, the elements are rapidly braked by C II, which is observed to be at least 20× overabundant in the disk with respect to other species. A prediction from this scenario is that different neutral elements should reach different v ion, depending on the ionization thresholds and strengths of driving line transitions. In particular, neutral Fe and Na are predicted to reach the radial velocities 0.5 and 3.3kms-1, respectively, before being ionized. In this paper, we study the absorption profiles of Fe and Na from the CS gas disk around β Pic, as obtained by HARPS at the ESO 3.6m telescope. We find that the Fe and Na velocity profiles are indeed shifted with respect to each other, confirming the model. The absence of an extended blue wing in the profile of Na, however, indicates that there must be some additional braking on the neutrals. We explore the possibility that the ion gas (dominated by C II) can brake the neutrals and conclude that about 2-5× more C than previously estimated is needed for the predicted line profile to be consistent with the observed one. © 2011. The American Astronomical Society. All rights reserved.

Kaldo V.,Karolinska Institutet | Ramnero J.,University of Stockholm | Jernelov S.,Karolinska Institutet
Journal of Consulting and Clinical Psychology | Year: 2015

Objective: The authors investigate a model on how clients' differential involvement in therapeutic methods mediates the effect of therapist support in psychological treatmentin this case, a cognitive behaviorally based bibliotherapy for insomnia, administered with or without supportive telephone calls. Method: Eighty-nine participants, who fulfilled diagnostic criteria for insomnia, had a mean age of 49.1 years (range, 18-73 years) and were predominantly female (77%), fairly well educated, and mainly Caucasian. Participants were randomized between a bibliotherapeutic self-help treatment and the same treatment with the addition of therapist support. Primary outcome measure was the Insomnia Severity Index. Data on involvement in different methods and aspects of the treatment were estimated by clients at posttreatment and validated against therapist ratings of client involvement during treatment. Structural equation modeling was used to test if the effect of therapeutic support on outcome was mediated by involvement in treatment. Results: Carrying out the treatment with therapist support significantly boosted the therapeutic effects. A mediational analysis with involvement in the three key treatment methods (sleep restriction, sleep compression, and stimulus control) as the mediator fully mediated the differential effect between the two conditions (Sobel test; r = .31; z = 2.173; p < .05) and explained 68.4% of the total effect. Conclusions: Therapeutic support improved outcome via higher patient involvement rather than having a direct effect on outcome. Thus, relationship and methods could be regarded as interactional, and patient involvement should be considered. These factors could be further studied in treatments where specific ingredients within the therapeutic contact can be experimentally manipulated. © 2015 American Psychological Association.

Nilsson A.S.,University of Stockholm
Upsala Journal of Medical Sciences | Year: 2014

The rise of antibiotic-resistant bacterial strains, causing intractable infections, has resulted in an increased interest in phage therapy. Phage therapy preceded antibiotic treatment against bacterial infections and involves the use of bacteriophages, bacterial viruses, to fight bacteria. Virulent phages are abundant and have proven to be very effective in vitro, where they in most cases lyse any bacteria within the hour. Clinical trials on animals and humans show promising results but also that the treatments are not completely effective. This is partly due to the studies being carried out with few phages, and with limited experimental groups, but also the fact that phage therapy has limitations in vivo. Phages are large compared with small antibiotic molecules, and each phage can only infect one or a few bacterial strains. A very large number of different phages are needed to treat infections as these are caused by genetically different strains of bacteria. Phages are effective only if enough of them can reach the bacteria and increase in number in situ. Taken together, this entails high demands on resources for the construction of phage libraries and the testing of individual phages. The effectiveness and host range must be characterized, and immunological risks must be assessed for every single phage. © 2014 Informa Healthcare.

Andreo P.,University of Stockholm
Physics in Medicine and Biology | Year: 2010

The authors of a recent paper (Wang and Rogers 2009 Phys. Med. Biol. 54 1609) have used the Monte Carlo method to simulate the 'classical' experiment made more than 30 years ago by Johansson et al (1978 National and International Standardization of Radiation Dosimetry (Atlanta 1977) vol 2 (Vienna: IAEA) pp 243-70) on the displacement (or replacement) perturbation correction factor p dis for cylindrical chambers in 60Co and high-energy photon beams. They conclude that an 'unreasonable normalization at d max' of the ionization chambers response led to incorrect results, and for the IAEA TRS-398 Code of Practice, which uses ratios of those results, 'the difference in the correction factors can lead to a beam calibration deviation of more than 0.5% for Farmer-like chambers'. The present work critically examines and questions some of the claims and generalized conclusions of the paper. It is demonstrated that for real, commercial Farmer-like chambers, the possible deviations in absorbed dose would be much smaller (typically 0.13%) than those stated by Wang and Rogers, making the impact of their proposed values negligible on practical high-energy photon dosimetry. Differences of the order of 0.4% would only appear at the upper extreme of the energies potentially available for clinical use (around 25 MV) and, because lower energies are more frequently used, the number of radiotherapy photon beams for which the deviations would be larger than say 0.2% is extremely small. This work also raises concerns on the proposed value of p dis for Farmer chambers at the reference quality of 60Co in relation to their impact on electron beam dosimetry, both for direct dose determination using these chambers and for the cross-calibration of plane-parallel chambers. The proposed increase of about 1% in p dis (compared with TRS-398) would lower the k Q factors and therefore D w in electron beams by the same amount. This would yield a severe discrepancy with the current good agreement between electron dosimetry based on an electron cross-calibrated plane-parallel chamber (against a Farmer) or on a directly 60Co calibrated plane-parallel chamber, which is not likely to be in error by 1%. It is suggested that the influence of the 60Co source spectrum used in the simulations may not be negligible for calculations aimed at an uncertainty level of 0.1%. © 2010 Institute of Physics and Engineering in Medicine.

Skageby J.,University of Stockholm
New Review of Hypermedia and Multimedia | Year: 2011

This paper introduces and explores cycles of pre-produsage and produsage. It reports on the results from an online ethnographical study of the Apple iPad conducted before the public release of the material product. Consequently, most users had not physically interacted with the device in question. Nevertheless, the release of the technical specifications and marketing material generated a massive amount of produsage-related online discussion. As such this paper explores the concept of pre-produsage. Pre-produsage is a form of predicted or expected use, relating to products or services that are only accessible to users as a form of representation (e.g. technical specification, virtual prototype, and design sketch), but with an added element of user-generated design suggestions, conflict coordination, and software development. Remediationthe process by which new digital media technologies reuses qualities of previous technologies and enters an existing media ecology-is a prevalent theme in pre-produsage and involves a tension between features that support protracted use and features that provide total innovation. The paper argues that an analysis of pre-produsage can provide insights that relate to both anticipated and actual user experience (UX). More specifically, pre-produsage analysis can trace the underlying reasons for a certain problem, intention, or concern and connect it to a specific set of features and potential solutions. Finally, the paper shows how proprietary products become subject to produsage, resulting in artifacts negotiated by cycles of produsage. © 2011 Taylor & Francis.

Webster S.G.,Bangor University | Keller R.,University of Bonn | Dircksen H.,University of Stockholm
General and Comparative Endocrinology | Year: 2012

Apart from providing an up-to-date review of the literature, considerable emphasis was placed in this article on the historical development of the field of "crustacean eyestalk hormones" A role of the neurosecretory eyestalk structures of crustaceans in endocrine regulation was recognized about 80. years ago, but it took another half a century until the first peptide hormones were identified. Following the identification of crustacean hyperglycaemic hormone (CHH) and moult-inhibiting hormone (MIH), a large number of homologous peptides have been identified to this date. They comprise a family of multifunctional peptides which can be divided, according to sequences and precursor structure, into two subfamilies, type-I and -II. Recent results on peptide sequences, structure of genes and precursors are described here. The best studied biological activities include metabolic control, moulting, gonad maturation, ionic and osmotic regulation and methyl farnesoate synthesis in mandibular glands. Accordingly, the names CHH, MIH, and GIH/VIH (gonad/vitellogenesis-inhibiting hormone), MOIH (mandibular organ-inhibiting hormone) were coined. The identification of ITP (ion transport peptide) in insects showed, for the first time, that CHH-family peptides are not restricted to crustaceans, and data mining has recently inferred their occurrence in other ecdysozoan clades as well. The long-held tenet of exclusive association with the eyestalk X-organ-sinus gland tract has been challenged by the finding of several extra nervous system sites of expression of CHH-family peptides. Concerning mode of action and the question of target tissues, second messenger mechanisms are discussed, as well as binding sites and receptors. Future challenges are highlighted. © 2011.

Schwander T.,University of Groningen | Leimar O.,University of Stockholm
Trends in Ecology and Evolution | Year: 2011

A major question for the study of phenotypic evolution is whether intra- and interspecific diversity originates directly from genetic variation, or instead, as plastic responses to environmental influences initially, followed later by genetic change. In species with discrete alternative phenotypes, evolutionary sequences can be inferred from transitions between environmental and genetic phenotype control, and from losses of phenotypic alternatives. From the available evidence, sequences appear equally probable to start with genetic polymorphism as with polyphenism, with a possible dominance of one or the other for specific trait types. We argue in this review that to evaluate the prevalence of each route, an investigation of both genetic and environmental cues for phenotype determination in several related rather than in isolated species is required. © 2011 Elsevier Ltd.

Faye I.,University of Stockholm | Lindberg B.G.,Imperial College London
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2016

Four decades ago, immunological research was dominated by the field of lymphoid biology. It was commonly accepted that multicellular eukaryotes defend themselves through phagocytosis. The lack of lymphoid cells in insects and other simpler animals, however, led to the common notion that they might simply lack the capacity defend themselves with humoral factors. This view was challenged by microbiologist Hans G. Boman and co-workers in a series of publications that led to the advent of antimicrobial peptides as a universal arm of the immune system. Besides ingenious research, Boman ignited his work by posing the right questions. He started off by asking himself a simple question: ‘Antibodies take weeks to produce while many microbes divide hourly; so how come we stay healthy?’. This led to two key findings in the field: the discovery of an inducible and highly potent antimicrobial immune response in Drosophila in 1972, followed by the characterization of cecropin in 1981. Despite broadly being considered an insect-specific response at first, the work of Boman and co-workers eventually created a bandwagon effect that unravelled various aspects of innate immunity. This article is part of the themed issue ‘Evolutionary ecology of arthropod antimicrobial peptides’. © 2016 The Author(s) Published by the Royal Society. All rights reserved.

Bengtsson L.,Karolinska Institutet | Lu X.,Karolinska Institutet | Lu X.,University of Stockholm | Thorson A.,Karolinska Institutet | And 2 more authors.
PLoS Medicine | Year: 2011

Background: Population movements following disasters can cause important increases in morbidity and mortality. Without knowledge of the locations of affected people, relief assistance is compromised. No rapid and accurate method exists to track population movements after disasters. We used position data of subscriber identity module (SIM) cards from the largest mobile phone company in Haiti (Digicel) to estimate the magnitude and trends of population movements following the Haiti 2010 earthquake and cholera outbreak. Methods and Findings: Geographic positions of SIM cards were determined by the location of the mobile phone tower through which each SIM card connects when calling. We followed daily positions of SIM cards 42 days before the earthquake and 158 days after. To exclude inactivated SIM cards, we included only the 1.9 million SIM cards that made at least one call both pre-earthquake and during the last month of study. In Port-au-Prince there were 3.2 persons per included SIM card. We used this ratio to extrapolate from the number of moving SIM cards to the number of moving persons. Cholera outbreak analyses covered 8 days and tracked 138,560 SIM cards. An estimated 630,000 persons (197,484 Digicel SIM cards), present in Port-au-Prince on the day of the earthquake, had left 19 days post-earthquake. Estimated net outflow of people (outflow minus inflow) corresponded to 20% of the Port-au-Prince pre-earthquake population. Geographic distribution of population movements from Port-au-Prince corresponded well with results from a large retrospective, population-based UN survey. To demonstrate feasibility of rapid estimates and to identify areas at potentially increased risk of outbreaks, we produced reports on SIM card movements from a cholera outbreak area at its immediate onset and within 12 hours of receiving data. Conclusions: Results suggest that estimates of population movements during disasters and outbreaks can be delivered rapidly and with potentially high validity in areas with high mobile phone use. Please see later in the article for the Editors' Summary. © 2011 Bengtsson et al.

Lee S.H.,Umea University | Holme P.,Umea University | Holme P.,Sungkyunkwan University | Holme P.,University of Stockholm
Physical Review Letters | Year: 2012

During the last decade of network research focusing on structural and dynamical properties of networks, the role of network users has been more or less underestimated from the bird's-eye view of global perspective. In this era of global positioning system equipped smartphones, however, a user's ability to access local geometric information and find efficient pathways on networks plays a crucial role, rather than the globally optimal pathways. We present a simple greedy spatial navigation strategy as a probe to explore spatial networks. These greedy navigators use directional information in every move they take, without being trapped in a dead end based on their memory about previous routes. We suggest that the centralities measures have to be modified to incorporate the navigators' behavior, and present the intriguing effect of navigators' greediness where removing some edges may actually enhance the routing efficiency, which is reminiscent of Braess's paradox. In addition, using samples of road structures in large cities around the world, it is shown that the navigability measure we define reflects unique structural properties, which are not easy to predict from other topological characteristics. In this respect, we believe that our routing scheme significantly moves the routing problem on networks one step closer to reality, incorporating the inevitable incompleteness of navigators' information. © 2012 American Physical Society.

Ljungdahl P.O.,University of Stockholm | Daignan-Fornier B.,Institut Universitaire de France | Daignan-Fornier B.,French National Center for Scientific Research
Genetics | Year: 2012

Ever since the beginning of biochemical analysis, yeast has been a pioneering model for studying the regulation of eukaryotic metabolism. During the last three decades, the combination of powerful yeast genetics and genome-wide approaches has led to a more integrated view of metabolic regulation. Multiple layers of regulation, from suprapathway control to individual gene responses, have been discovered. Constitutive and dedicated systems that are critical in sensing of the intra- and extracellular environment have been identified, and there is a growing awareness of their involvement in the highly regulated intracellular compartmentalization of proteins and metabolites. This review focuses on recent developments in the field of amino acid, nucleotide, and phosphate metabolism and provides illustrative examples of how yeast cells combine a variety of mechanisms to achieve coordinated regulation of multiple metabolic pathways. Importantly, common schemes have emerged, which reveal mechanisms conserved among various pathways, such as those involved in metabolite sensing and transcriptional regulation by noncoding RNAs or by metabolic intermediates. Thanks to the remarkable sophistication offered by the yeast experimental system, a picture of the intimate connections between the metabolomic and the transcriptome is becoming clear. © 2012 by the Genetics Society of America.

Dahlberg, D. 2015. Categories are all around us: Towards more porous, flexible, and negotiable boundaries in conservation-production landscapes. Norsk Geografisk Tidsskrift–Norwegian Journal of Geography Vol. 00, 00–00. ISSN 0029-1951. In order to communicate and act in the world we divide it into categories, with boundaries that define belonging and exclusion. Categories take shape through processes influenced by, for example, history, discourses, ecologies, and power relations. Although we intellectually know that categories are social constructs we tend to treat them as if they have an intrinsic reality of their own when we describe and act in any given landscape. This understanding is explored within a political ecology framework through a case study of protected areas in relation to other land uses in Sweden. The study relies primarily on interviews with actors affected by conservation efforts, and highlights that categories are not neutral phenomenon, but have ecological, material and social effects in the landscape. It discusses how the simplification of a complex and dynamic whole into static categories can result in paradoxes with unexpected and sometimes negative effects on rural development and land care arrangements. The study advocates a more flexible understanding and handling of categories – and thus of landscapes – to enhance the potential for multiple landscape values to exist in overlapping, dynamic and paradoxical ways. © 2015 Norwegian Geographical Society.

Widgren M.,University of Stockholm
Norsk Geografisk Tidsskrift | Year: 2015

Widgren, M. 2015. Linking Nordic landscape geography and political ecology. Norsk Geografisk Tidsskrift–Norwegian Journal of Geography Vol. 00, 00–00. ISSN 0029-1951 The article analyses and compares two schools of landscape research – post-war European landscape history and Nordic landscape geography – and compares them with political ecology. Each of them developed within a specific political, environmental, and intellectual context. European landscape history developed as curiosity-driven research, but in the shadow of previous ideological misuse of settlement history. Political ecology developed in the context of the Sahel crisis and provided a radical answer to Malthusian simplifications of the desertification and land degradation. In contrast to that, Nordic landscape geography grew as an intellectual critical reaction to a European situation in which post-productivist landscape policies were on the agenda. The article also speculates on challenges ahead and suggests that the epoch when we understand European landscapes mainly from a post-productivist standpoint may be over. © 2015 Norwegian Geographical Society.

Lander I.,University of Stockholm
British Journal of Criminology | Year: 2015

This article focuses on the ageing process among drug-using women, proceeded on the basis of a critical post-structural approach to the life course (Holstein and Gubrium 2000; Halberstam 2005; Ahmed 2006; Mattsson 2014). The objective is to provide an alternative perspective on the life course to that which dominates current criminology. This perspective challenges prevailing norms and conceptions regarding the other, and in doing so focuses the analysis on the social mechanisms that lie behind social exclusion, crime and drug use. By means of the retrospective narratives of 4 women, who describe a rambling journey along crooked paths on the margins of the welfare state, the article reveals the nature of prevailing norms and conceptions regarding ageing, gender and drug use. © 2014 The Author.

AIM-Alcohol consumption on an aggregate level rose by 30 percent in Sweden between 1996 and 2004 according to available research. However, alcohol-related harm has not increased as much as expected. The purpose of this study is to analyze how the self-reported alcohol consumption changed between 1996 and 2005. DATA-Self-reported alcohol consumption was investigated with four identical surveys implemented by Statistics Sweden, 1996 (n = 5891, response rate 78.7 %), 1997 (n = 5807, response rate 77.8 %), 2004 (n = 5591, response rate 74.8 %) and 2006 (4277, response rate 75.1 %). In addition to weekly volume of alcohol consumption, we have data on beverage specific consumption, daily alcohol consumption for the different days of the week, frequency of binge drinking and several background variables of good quality. RESULTS-Self-reported alcohol consumption rose between 96/97 and 04/05, but only with 15 percent. The increase was relatively evenly distributed but women, older people and low to middle consumer groups increased their consumption the most. The frequency of binge drinking also increased as did the proportion of alcohol consumed during the weekend. CONCLUSIONS-The increase in alcohol consumption was smaller in our study than the increase reported earlier. A few changes in the consumption pattern that could explain a diverging trend between the total alcohol consumption and alcohol related harms were found.

The Scandinavian wolf population descends from only five individuals, is isolated, highly inbred and exhibits inbreeding depression. To meet international conservation goals, suggestions include managing subdivided wolf populations over Fennoscandia as a metapopulation; a genetically effective population size of Ne⩾500, in line with the widely accepted long-term genetic viability target, might be attainable with gene flow among subpopulations of Scandinavia, Finland and Russian parts of Fennoscandia. Analytical means for modeling Ne of subdivided populations under such non-idealized situations have been missing, but we recently developed new mathematical methods for exploring inbreeding dynamics and effective population size of complex metapopulations. We apply this theory to the Fennoscandian wolves using empirical estimates of demographic parameters. We suggest that the long-term conservation genetic target for metapopulations should imply that inbreeding rates in the total system and in the separate subpopulations should not exceed Δf=0.001. This implies a meta-Ne of NeMeta⩾500 and a realized effective size of each subpopulation of NeRx⩾500. With current local effective population sizes and one migrant per generation, as recommended by management guidelines, the meta-Ne that can be reached is ~250. Unidirectional gene flow from Finland to Scandinavia reduces meta-Ne to ~130. Our results indicate that both local subpopulation effective sizes and migration among subpopulations must increase substantially from current levels to meet the conservation target. Alternatively, immigration from a large (Ne⩾500) population in northwestern Russia could support the Fennoscandian metapopulation, but immigration must be substantial (5–10 effective immigrants per generation) and migration among Fennoscandian subpopulations must nevertheless increase.Heredity advance online publication, 22 June 2016; doi:10.1038/hdy.2016.44. © 2016 The Genetics Society

Geissler F.,University of Wurzburg | Budich J.C.,University of Stockholm | Trauzettel B.,University of Wurzburg
New Journal of Physics | Year: 2013

Silicene consists of a monolayer of silicon atoms in a buckled honeycomb structure. It was recently discovered that the symmetry of such a system allows for interesting Rashba spin-orbit effects. A perpendicular electric field is able to couple to the sublattice pseudospin, making it possible to electrically tune and close the band gap. Therefore, external electric fields may generate a topological phase transition from a topological insulator to a normal insulator (or semimetal) and vice versa. The contribution of the present paper to the study of silicene is twofold. Firstly, we perform a group theoretical analysis to systematically construct the Hamiltonian in the vicinity of the K points of the Brillouin zone and find an additional, electric field induced spin-orbit term, that is allowed by symmetry. Subsequently, we identify a tight-binding model that corresponds to the group theoretically derived Hamiltonian near the K points. Secondly, we start from this tight-binding model to analyze the topological phase diagram of silicene by an explicit calculation of the topological invariant of the band structure. To this end, we calculate the topological invariant of the honeycomb lattice in a manifestly gauge invariant way which allows us to include Sz symmetry breaking terms - like Rashba spin-orbit interaction - into the topological analysis. Interestingly, we find that the interplay of a Rashba and an intrinsic spin-orbit term can generate a non-trivial quantum spin Hall phase in silicene. This is in sharp contrast to the more extensively studied honeycomb system graphene where Rashba spin-orbit interaction is known to compete with the quantum spin Hall effect in a detrimental way. © IOP Publishing and Deutsche Physikalische Gesellschaft.

Ekendahl M.,University of Stockholm
Addiction Research and Theory | Year: 2011

Background: It is widely acknowledged that the social meaning of maintenance treatment (MT) with methadone is context-dependent and that different discourses influence how this approach to opiate addiction problems is practised. In Sweden, MT has long been ideologically controversial, even if the past decade's emphasis on evidence-based interventions has made it more accepted and prevalent in the treatment system. MT may thus be seen as a discursive field where science and values are intertwined and impact practice jointly, which emphasises the importance of analysing how MT is attributed with meaning. Objectives: The study aims to identify and analyse the discourses that service providers in Swedish opiate addiction treatment refer to in their efforts to legitimise MT. Methods: Twenty-eight interviews focused on MT-related issues were conducted with Swedish social workers and health care workers. The material was analysed qualitatively according to discourse theory. Findings: Three key features of MT were identified: as therapeutic intervention; as beyond harm reduction and as pragmatic solution. The respondents constructed MT as a necessary medical and psychosocial treatment aimed at rehabilitation and patients' complete break with drug abuse, which reflects a policy-context where solutions to drug problems are supposed to be resolute, thorough and abstinence-oriented. Conclusions: The service providers handled the controversy between science and values by drawing on a decent-life discourse, where opiate addiction problems are solved with a pragmatic stance towards evidence and where only interventions that make patients' lives allegedly decent are considered legitimate (excluding, e.g. heroin prescription and liberal methadone distribution). Copyright © 2010 Informa UK Ltd.

Tacon A.G.J.,University of Sao Paulo | Metian M.,University of Stockholm
Reviews in Fisheries Science | Year: 2013

In a world where nearly 30% of humanity is suffering from malnutrition and over 70% of the planet is covered with water, aquatic foods represent an essential component of the global food basket to improve the nutrition, health, and well being of all peoples.It is not by chance that Japan, the country with one of the world's highest reported life expectancies and lowest incidences of obesity and deaths from heart related illnesses, is also one of the world's top consumers of captured and farmed aquatic animal food products and aquatic plants. According to the FAO, in 2009, total captured and farmed aquatic animal food products accounted for 16.6% of the global population's intake of animal protein, providing more than three billion people with almost 20% of their average per capita intake of animal protein, and 4.3 billion people with at least 15% of such protein.This article reviews the nutritional composition of different farmed and captured aquatic food products and compares these with conventional terrestrial meat products. In addition to the superior nutritional profile and benefits of aquatic animal food products, small-sized marine pelagic fish play an important role in the nutrition of the poor as an affordable and much needed source of high quality animal protein and essential amino acids, omega-3 fatty acids, vitamins, minerals, and trace elements. As one of the best aquatic animal foods from a nutritional perspective, the direct consumption of small pelagic fish should be encouraged and promoted, as apposed to the continued targeted use of these species for reduction into fishmeal and fish oil for use in animal feeds. © 2013 Copyright Taylor and Francis Group, LLC.

Kodandaramaiah U.,University of Stockholm
Current Zoology | Year: 2011

Molecular dating techniques require the use of calibrations, which are usually fossil or geological vicariance-based. Fossil calibrations have been criticised because they result only in minimum age estimates. Based on a historical biogeographic perspective, I suggest that vicariance-based calibrations are more dangerous. Almost all analytical methods in historical biogeography are strongly biased towards inferring vicariance, hence vicariance identified through such methods is unreliable. Other studies, especially of groups found on Gondwanan fragments, have simply assumed vicariance. Although it was previously believed that vicariance was the predominant mode of speciation, mounting evidence now indicates that speciation by dispersal is common, dominating vicariance in several groups. Moreover, the possibility of speciation having occurred before the said geological event cannot be precluded. Thus, geological calibrations can under- or overestimate times, whereas fossil calibrations always result in minimum estimates. Another major drawback of vicariant calibrations is the problem of circular reasoning when the resulting estimates are used to infer ages of biogeographic events. I argue that fossil-based dating is a superior alternative to vicariance, primarily because the strongest assumption in the latter, that speciation was caused by the said geological process, is more often than not the most tenuous. When authors prefer to use a combination of fossil and vicariant calibrations, one suggestion is to report results both with and without inclusion of the geological constraints. Relying solely on vicariant calibrations should be strictly avoided. © 2011 Current Zoology.

Kolk M.,University of Stockholm
Population Studies | Year: 2014

The study of the intergenerational transmission of fertility has a long history in demography, but until now research has focused primarily on parents' influence on their children's fertility patterns and has largely overlooked the possible influence of other kin. This study examines the transmission of fertility patterns from parents, grandparents, uncles, and aunts, using event history models to determine the risk of first, second, and third births. Swedish register data are used to study the 1970-82 birth cohorts. The findings indicate strong associations between the fertility of index persons and that of their parents, and also independent associations between the completed fertility of index persons and that of their grandparents and parents' siblings. The results suggest that, when examining background effects in fertility research, it is relevant to take a multigenerational perspective and to consider the characteristics of extended kin. © 2013 Population Investigation Committee.

Adel A.,University of Stockholm
Journal of Pragmatics | Year: 2011

How do students build rapport in online group work, especially if all they have to work with is asynchronous text? Taking this question as a point of departure, this paper presents research into the 'interactional' function in group work among university students, specifically investigating rapport-building language use, defined as communicative acts promoting social concord. Rapport building is examined in online student group work, using written material in the form of discussion board messages (from the Mid-Sweden Corpus of Computer-Assisted Language Learning). To help bring out what is characteristic of the online type of discourse, spoken face-to-face material also representing student-student interaction (from the Michigan Corpus of Academic Spoken English) is included. Frequency word lists based on the two sets of material were used in combination with concordancing in order to find which of the most frequent expressions functioned as rapport building, thus combining corpus-based and discourse-analytical methods. A taxonomy of rapport-building discourse functions was developed, containing four major categories: discourse-structuring, intratextual, face-saving and bonding units. Each of these covers specific discourse functions; in the case of bonding units, these are Agreeing; Aligning with in-group; Commiserating; Complimenting; Seeking agreement; Offering encouragement; Thanking; Responding to thanks; and Chatting. © 2011 Elsevier B.V.

Copolovici D.M.,University of Tartu | Langel K.,University of Tartu | Eriste E.,University of Tartu | Langel U.,University of Tartu | Langel U.,University of Stockholm
ACS Nano | Year: 2014

The intrinsic property of cell-penetrating peptides (CPPs) to deliver therapeutic molecules (nucleic acids, drugs, imaging agents) to cells and tissues in a nontoxic manner has indicated that they may be potential components of future drugs and disease diagnostic agents. These versatile peptides are simple to synthesize, functionalize, and characterize yet are able to deliver covalently or noncovalently conjugated bioactive cargos (from small chemical drugs to large plasmid DNA) inside cells, primarily via endocytosis, in order to obtain high levels of gene expression, gene silencing, or tumor targeting. Typically, CPPs are often passive and nonselective yet must be functionalized or chemically modified to create effective delivery vectors that succeed in targeting specific cells or tissues. Furthermore, the design of clinically effective systemic delivery systems requires the same amount of attention to detail in both design of the delivered cargo and the cell-penetrating peptide used to deliver it. © 2014 American Chemical Society.

Gerholm T.,University of Stockholm
Journal of Pragmatics | Year: 2011

This article addresses the origin and development of facework practices in young children by focusing on two kinds of practices in child-parent interaction: (1) situations in which a child's verbal and nonverbal emotive expressions indicate a need to save face; and (2) situations in which a child uses various strategies in order to save face. Through illustrations from a longitudinal material of child-adult interaction it is argued that emotive reactions constitute the base for face awareness in children. This awareness in time turns to child facework practices, a process aided and shaped by the interactional routines with parents. The central aim of the article is to highlight these two aspects of facework, one internal, emotional and related to face; the other external and interactional. As a second aim the article will enforce that the way we analyze interaction must be transparent in that it can be understood, reviewed and contested by others. © 2011 Elsevier B.V.

Andersson A.,University of Stockholm
Science of the Total Environment | Year: 2011

Estimating the relative contributions from multiple potential sources of a specific component in a mixed environmental matrix is a general challenge in diverse fields such as atmospheric, environmental and earth sciences. Perhaps the most common strategy for tackling such problems is by setting up a system of linear equations for the fractional influence of different sources. Even though an algebraic solution of this approach is possible for the common situation with N. +. 1 sources and N source markers, such methodology introduces a bias, since it is implicitly assumed that the calculated fractions and the corresponding uncertainties are independent of the variability of the source distributions. Here, a random sampling (RS) strategy for accounting for such statistical bias is examined by investigating rationally designed synthetic data sets. This random sampling methodology is found to be robust and accurate with respect to reproducibility and predictability. This method is also compared to a numerical integration solution for a two-source situation where source variability also is included. A general observation from this examination is that the variability of the source profiles not only affects the calculated precision but also the mean/median source contributions. © 2011 Elsevier B.V.

Carlsson C.,University of Stockholm
International Journal of Offender Therapy and Comparative Criminology | Year: 2013

This article explores the concept of "intermittency" and uses qualitative life history narratives with male offenders from The Stockholm Life Course Project to distinguish between two qualitatively different forms of intermittent offending. Findings suggest that one form of intermittency can be characterized by "breaks" and "pauses" in offending, where the offender for a period of time "holds up" but without attempting to commit to any long-term change in trajectory. The second form can best be understood as incomplete or aborted attempts at desistance, where attempts to change are present but not realized. Perceived or experienced failure to enter conventional roles and engage in conventional practices is highly relevant to understand these attempts. The intermittent zigzag patterns of offending observed in quantitative studies of criminal careers can thus actually entail qualitatively different life course processes of continuity and change. Implications for policy and future research are highlighted. © The Author(s) 2012.

Siegbahn P.E.M.,University of Stockholm
Physical Chemistry Chemical Physics | Year: 2012

The new high-resolution X-ray structure of photosystem II has allowed more detailed studies than before of water oxidation at the oxygen evolving complex (OEC). In the present study the two final S-transitions of water oxidation are studied. The electron coupled proton transfers are followed from the center of the OEC to Asp61, which is considered as the start of the transfer chain through the protein to the lumenal side. It is found that the proton transfers occur in multiple steps. Structures of intermediates and energy diagrams are derived and compared to experimental observations. Since the new experimental structure of the OEC is very similar to the one suggested earlier by density functional calculations, the O-O bond formation step remains essentially the same as the one suggested five years ago. An interesting new result is that the barrier for proton transfer within the OEC actually competes with the O-O bond formation step of being rate-limiting. © 2012 the Owner Societies.

Water is a natural resource whose control for productive purposes is often in the hands of men. Societies grounded on such unequal gender relations have been defined 'hydropatriarchies'. Against this background, this paper presents a gender analysis of landscape investments, conceptualised as landesque capital in smallholder irrigation farming in East Africa. Based on the analysis of how local gender contracts are negotiated, I argue that as processes of landesque capital formation are often explicitly gendered, attentiveness to gender dynamics is required to fully understand such practices. Moreover, as investments in landesque capital, for example, irrigation, terracing and drainage systems, have primarily been conceptualised as the result of men's systematic work, this study highlights women's contributions to the creation of landesque capital, taking smallholder irrigation as an example. Findings show that a distinction between 'incremental' and 'systematic' change (Doolittle 1984; Annals of the Association of American Geographers 74 124-37) is central to understanding the gender dynamics of landesque capital investment, but it is not sufficient. As women's work processes are typically not systematic, possibly promoting incremental change, they contribute to the production of landesque capital by supporting and facilitating men's work. However, the work of women is, as a rule, homogenised and stereotypically rendered as reproductive and secondary, due to the underlying cultural norms that limit, control or exploit women. This conceptualisation, or rather lack of, I argue, risks leading to a gender-blind analysis of land use intensification processes. Building on the gendered and symbolic nature of landesque capital, I propose a local gender contract analysis that integrates the cultural, symbolic and physical dimensions of the local gender division of labour into agricultural work and landscape change processes. © 2014 Royal Geographical Society (with the Institute of British Geographers).

Bellamy A.S.,University of Stockholm
Agriculture and Human Values | Year: 2011

This paper presents research conducted during two coffee farming seasons in Costa Rica. The study examined coffee farmers' weed management practices and is presented in the form of a case study of small-scale farmers' use of labor and herbicides in weed management practices. Over 200 structured interviews were conducted with coffee farmers concerning their use of hired labor and family labor, weed management activities, support services, and expectations about the future of their coffee production. ANOVA and regression analyses describe the relationships between farm size, labor, and herbicide use, and three farm types (i. e., conventional, semi-conventional, and organic). Based on findings regarding the amount of labor used to manually control weeds on different types of farms (large farms, small conventional, semi-conventional, and organic farms) I am able to challenge small conventional farmers' perceived need for herbicide use. Semi-structured interviews of coffee farmers and extension workers further revealed a dominant role played by agro-chemical companies in assisting farmers with production problems, and documented a high transaction cost for information provided from elsewhere. Chemical companies hire extension workers to visit farmers at their farms, free of charge, to offer recommendations on how to treat different pest problems, while government and cooperative extension agents charge for the service. There is a need to increase the amount of resources available to the National Coffee Institute to fund one-on-one farmer support services in order to balance the influence of agro-chemical company representatives and allow farmers to make better decisions regarding weed management. © 2010 Springer Science+Business Media B.V.

This article presents a review of the spatio-temporal pattern of the mid-Holocene Thermal Maximum as it occurs in 60 different reconstructions of annual mean temperature from locations around the globe. The geographical coherency of multi-centennial periods with annual mean temperatures at least 1°C and 2°C above the pre-industrial (~1750 AD) equivalents are presented. Although the reconstructions show a heterogeneous temperature pattern for the period c. 10-8 ka BP, a rather coherent period of temperatures exceeding the pre-industrial ones are seen for c. 8-4 ka BP. The onset of the Neoglaciation takes place 4-3 ka BP and cumulates during the Little Ice Age (c. 1300-1900 AD). Overall, our review points towards a more homogeneous mid-Holocene Thermal Maximum than hitherto reported. However, the still limited data coverage, especially for the Southern Hemisphere, restricts the possibility to draw any firm conclusion regarding the amplitude and spatio-temporal pattern of the maximum mid-Holocene warming.

Ahnland L.,University of Stockholm
Scandinavian Economic History Review | Year: 2015

This study presents new time series data for private debt in Sweden in 1900–2013, including credit from banks, mortgage institutes and credit companies. The reconstruction of the data is a scientific task by itself, and is complicated by changed definitions, breaks in the series, and the need for occasional interpolation and cross-reference of sources. The obtained data reveal both qualitative and quantitative changes in the structure of private debt in Sweden during the period. One finding is a pattern where the era starting with the deregulation of the credit market in 1985 resembles the era preceding World War Two. Both periods experienced a high level of private debt-to-GDP ratio as well as severe financial crises. In a first application of the data, the hypothesis of rising private debt in the years before a financial crisis is explored through logit regression. The findings are in line with international research, and suggest that higher lending, especially from banks, might aggravate the risk of financial crisis. © 2015 Taylor & Francis.

Menegon L.,University of Tromso | Piazolo S.,University of Stockholm | Pennacchioni G.,University of Padua
Contributions to Mineralogy and Petrology | Year: 2011

We present an electron backscatter diffraction analysis of five quartz porphyroclasts in a greenschist facies (T = 300-400°C) granitoid protomylonite from the Arolla unit of the NW Alps. Mechanical Dauphiné twinning developed pervasively during the incipient stage of deformation within two porphyroclasts oriented with a negative rhomb plane {z} almost orthogonal to the compression direction (z-twin orientation). Twinning was driven by the anisotropy in the elastic compliance of quartz and resulted in the alignment of the poles of the planes of the more compliant positive rhomb {r} nearly parallel to the compression direction (r-twin orientation). In contrast, we report the lack of twinning in two porphyroclasts already oriented with one of the {r} planes orthogonal to the compression direction. One twinned porphyroclast has been investigated with more detail. It shows the localization of much of the plastic strain into discrete r-twins as a consequence of the higher amount of elastic strain energy stored by r-twins in comparison to z-twins. The presence of Dauphiné twins induced a switch in the dominant active slip systems during plastic deformation, from basal (regions without twinning) to {π} and {π′} (pervasively twinned regions). Dynamic recrystallization is localized along an r-twin and occurred dominantly by progressive subgrain rotation, with a local component of bulging recrystallization. Part of the recrystallized grains underwent rigid-body rotation, approximately about the bulk vorticity axis, which accounts for the development of large misorientation angles. The recrystallized grain size piezometer for quartz yields differential stress of 100 MPa. The comparison of this palaeostress estimate with literature data suggests that mechanical Dauphiné twinning could have a potential use as palaeopiezometer in quartz-bearing rocks. © 2010 The Author(s).

Johansson A.S.,University of Stockholm
PloS one | Year: 2012

Neurodegeneration in protein-misfolding disease is generally assigned to toxic function of small, soluble protein aggregates. Largely, these assignments are based on observations of cultured neural cells where the suspect protein material is titrated directly into the growth medium. In the present study, we use this approach to shed light on the cytotoxic action of the metalloenzyme Cu/Zn superoxide dismutase 1 (SOD1), associated with misfolding and aggregation in amyotrophic lateral sclerosis (ALS). The results show, somewhat unexpectedly, that the toxic species of SOD1 in this type of experimental setting is not an aggregate, as typically observed for proteins implicated in other neuro-degenerative diseases, but the folded and fully soluble apo protein. Moreover, we demonstrate that the toxic action of apoSOD1 relies on the protein's ability to chelate Zn(2+) ions from the growth medium. The decreased cell viability that accompanies this extraction is presumably based on disturbed Zn(2+) homeostasis. Consistently, mutations that cause global unfolding of the apoSOD1 molecule or otherwise reduce its Zn(2+) affinity abolish completely the cytotoxic response. So does the addition of surplus Zn(2+). Taken together, these observations point at a case where the toxic response of cultured cells might not be related to human pathology but stems from the intrinsic limitations of a simplified cell model. There are several ways proteins can kill cultured neural cells but all of these need not to be relevant for neurodegenerative disease.

Kodandaramaiah U.,University of Stockholm
Journal of Biogeography | Year: 2010

Aim Analytical methods are commonly used to identify historical processes of vicariance and dispersal in the evolution of taxa. Currently, dispersal-vicariance analysis implemented in the software diva is the most widely used method. Despite some recognized shortcomings of the method, it has been treated as error-free in many cases and used extensively as the sole method to reconstruct histories of taxa. In light of this, an evaluation of the limitations of the method is needed, especially in relation to several newer alternatives. Methods In an approach similar to simulation studies in phylogenetics, I use hypothetical taxa evolving in specific geological scenarios and test how well diva reconstructs their histories. Results diva reconstructs histories accurately when evolution has been simple; that is, where speciation is driven mainly by vicariance. Ancestral areas are wrongly identified under several conditions, including complex patterns of dispersals and within-area speciation events. Several potentially serious drawbacks in using diva for inferences in biogeography are discussed. These include the inability to distinguish between contiguous range expansions and across-barrier dispersals, a low probability of invoking extinctions, incorrect constraints set on the maximum number of areas by the user, and analysing the ingroup taxa without sister groups. Main conclusions Most problems with inferences based on diva are linked to the inflexibility and simplicity of the assumptions used in the method. These are frequently invalid, resulting in spurious reconstructions. I argue that it might be dangerous to rely solely on diva optimization to infer the history of a group. I also argue that diva is not ideally suited to distinguishing between dispersal and vicariance because it cannot a priori take into account the age of divergences relative to the timing of barrier formation. I suggest that other alternative methods can be used to corroborate the findings in diva, increasing the robustness of biogeographic hypotheses. I compare some important alternatives and conclude that model-based approaches are promising. © 2009 Blackwell Publishing Ltd.

Simmons T.R.,CNRS Chemistry and Biology of Metals Laboratory | Berggren G.,CNRS Chemistry and Biology of Metals Laboratory | Berggren G.,University of Stockholm | Bacchi M.,CNRS Chemistry and Biology of Metals Laboratory | And 3 more authors.
Coordination Chemistry Reviews | Year: 2014

Over the last 15 years, a plethora of research has provided major insights into the structure and function of hydrogenase enzymes. This has led to the important development of chemical models that mimic the inorganic enzymatic co-factors, which in turn has further contributed to the understanding of the specific molecular features of these natural systems that facilitate such large and robust enzyme activities. More recently, efforts have been made to generate guest-host models and artificial hydrogenases, through the incorporation of transition metal-catalysts (guests) into various hosts. This adds a new layer of complexity to hydrogenase-like catalytic systems that allows for better tuning of their activity through manipulation of both the first (the guest) and the second (the host) coordination spheres. Herein we review the aforementioned advances achieved during the last 15 years, in the field of inorganic biomimetic hydrogenase chemistry. After a brief presentation of the enzymes themselves, as well as the early bioinspired catalysts, we review the more recent systems constructed as models for the hydrogenase enzymes, with a specific focus on the various strategies employed for incorporating of synthetic models into supramolecular frameworks and polypeptidic/protein scaffolds, and critically discuss the advantages of such an elaborate approach, with regard to the catalytic performances. © 2014 Elsevier B.V.

Siegbahn P.E.M.,University of Stockholm
Physical Chemistry Chemical Physics | Year: 2014

The main parts of the water oxidation mechanism in photosystem II have now been established both from theory and experiments. Still, there are minor questions remaining. One of them concerns the charge and the protonation state of the oxygen evolving complex (OEC). Previously, theory and experiments have agreed that the two water derived ligands on the outer manganese should be one hydroxide and one water. In the present study it is investigated whether both of them could be water. This question is addressed by a detailed study of energy diagrams, but in this context it is more conclusive to compare the redox potential of the OEC to the one of TyrZ. Both procedures lead to the conclusion that one of the ligands is a hydroxide. Another question concerns the protonation of the second shell His337, where the results are more ambiguous. The final part of the present study describes results when calcium is removed from the OEC. Even though protons enter to compensate the charge of the missing Ca2+, the redox potential and the pKa value of the OEC change dramatically and prevent the progress after S2. © 2014 the Partner Organisations.

Bintanja R.,Royal Netherlands Meteorological Institute | Graversen R.G.,Royal Netherlands Meteorological Institute | Graversen R.G.,University of Stockholm | Hazeleger W.,Royal Netherlands Meteorological Institute | Hazeleger W.,Wageningen University
Nature Geoscience | Year: 2011

Pronounced warming in the Arctic region, coined Arctic amplification, is an important feature of observed and modelled climate change1,2. Arctic amplification is generally attributed to the retreat of sea-ice3 and snow, and the associated surface-albedo feedback4, in conjunction with other processes5-8. In addition, the predominant thermal surface inversion in winter has been suggested to pose a negative feedback to Arctic warming by enhancing infrared radiative cooling9. Here we use the coupled climate model EC-Earth10 in idealized climate change experiments to quantify the individual contributions of the surface and the atmosphere to infrared radiative cooling. We find that the surface inversion in fact intensifies Arctic amplification, because the ability of the Arctic wintertime clear-sky atmosphere to cool to space decreases with inversion strength. Specifically, we find that the cold layers close to the surface in Arctic winter, where most of the warming takes place, hardly contribute to the infrared radiation that goes out to space. Instead, the additional radiation that is generated by the warming of these layers is directed downwards, and thus amplifies the warming. We conclude that the predominant Arctic wintertime temperature inversion damps infrared cooling of the system, and thus constitutes a positive warming feedback. © 2011 Macmillan Publishers Limited. All rights reserved.

Brandenburg A.,KTH Royal Institute of Technology | Brandenburg A.,University of Stockholm
Astrophysical Journal | Year: 2014

Using direct numerical simulations of three-dimensional hydromagnetic turbulence, either with helical or non-helical forcing, we show that the kinetic-to-magnetic energy dissipation ratio always increases with the magnetic Prandtl number, i.e., the ratio of kinematic viscosity to magnetic diffusivity. This dependence can always be approximated by a power law, but the exponent is not the same in all cases. For non-helical turbulence, the exponent is around 1/3, while for helical turbulence it is between 0.6 and 2/3. In the statistically steady state, the rate of energy conversion from kinetic into magnetic by the dynamo must be equal to the Joule dissipation rate. We emphasize that for both small-scale and large-scale dynamos, the efficiency of the energy conversion depends sensitively on the magnetic Prandtl number, and thus on the microphysical dissipation process. To understand this behavior, we also study shell models of turbulence and one-dimensional passive and active scalar models. We conclude that the magnetic Prandtl number dependence is qualitatively best reproduced in the one-dimensional model as a result of dissipation via localized Alfvén kinks. © 2014. The American Astronomical Society. All rights reserved.

Ahacic K.,Karolinska Institutet | Kreholt I.,University of Stockholm
Pain | Year: 2010

We examined age, period, and cohort patterns in musculoskeletal pain prevalence between 1968 and 2002 in the Swedish population. A repeated nationally representative survey allowed cross-sectional comparisons of ages 18-75 (5 waves n ≈ 5000), and ages 77+ at later waves (2 waves n ≈ 500). Cross-sectional 10-year age group differences in 5 waves, time-lag differences between waves (shifts across time) for age groups, and within-cohort differences between waves for 10-year birth cohorts followed over time were analyzed using graphs and ordered logistic regressions. The outcome scale was based on the three items measuring slight or severe pain in back, shoulder, and joints during the past 12 months. Age-period-cohort models showed that pain prevalence increased with age - mild or severe at all locations. Adjusted for the age-related increase, the cohorts followed over time did not show significant period change, except for cohorts born during 1940s. Beginning with the 1940s' cohorts pain prevalence increased over the period, and after baseline later cohorts also entered adulthood and the study with a higher pain prevalence. The prevalence of pain in the adult population thus increased with the passage through age and time of the 1940s cohorts. While there were no pronounced cohort differences at baseline in 1968, results demonstrated strong age effects in pain. The results indicate that the prevalence of musculoskeletal pain among the oldest age groups may increase in the future, when more baby-boomers are entering their oldest ages. © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Routh J.,IISER Kolkata | Hjelmquist P.,University of Stockholm
Applied Geochemistry | Year: 2011

Sediments from a core retrieved during installation of a shallow drinking water well in Ambikanagar (West Bengal, India) were analyzed for various physical and chemical parameters. The geochemical analyses included: (1) a 4-step sequential extraction scheme to determine the distribution of As between different fractions, (2) As speciation (As 3+ vs. As 5+), and (3) C, N and S isotopes. The sediments have a low percentage of organic C and N (0.10-0.56% and 0.01-0.05%, respectively). Arsenic concentration is between 2 and 7mgkg -1, and it is mainly associated with the residual fraction, less susceptible to chemical weathering. The proportion of As 3+ in these sediments is high and ranges from 24% to 74%. Arsenic in the second fraction (reducible) correlates well with Mn, and in the residual fraction As correlates well with several transition elements. The stable isotope results indicate microbial oxidation of organic matter involving SO 4 reduction. Oxidation of primary sulfide minerals and release of As from reduction of Fe-(oxy)hydroxides do not seem important mechanisms in As mobilization. Instead, the dominance of As 3+ and presence of As 5+ reducing microorganisms in this shallow aquifer imply As remobilization involving microbial processes that needs further investigations. © 2011 Elsevier Ltd.

Perreault C.,Santa Fe Institute | Mathew S.,University of Stockholm
PLoS ONE | Year: 2012

Language is a key adaptation of our species, yet we do not know when it evolved. Here, we use data on language phonemic diversity to estimate a minimum date for the origin of language. We take advantage of the fact that phonemic diversity evolves slowly and use it as a clock to calculate how long the oldest African languages would have to have been around in order to accumulate the number of phonemes they possess today. We use a natural experiment, the colonization of Southeast Asia and Andaman Islands, to estimate the rate at which phonemic diversity increases through time. Using this rate, we estimate that present-day languages date back to the Middle Stone Age in Africa. Our analysis is consistent with the archaeological evidence suggesting that complex human behavior evolved during the Middle Stone Age in Africa, and does not support the view that language is a recent adaptation that has sparked the dispersal of humans out of Africa. While some of our assumptions require testing and our results rely at present on a single case-study, our analysis constitutes the first estimate of when language evolved that is directly based on linguistic data. © 2012 Perreault, Mathew.

McNamara J.M.,University of Bristol | Leimar O.,University of Stockholm
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2010

In applying game theory to problems in biology, differences between individuals are often ignored. In particular, when analysing the evolution of cooperation it is often implicitly assumed that ignoring variation will produce predictions that approximate the solution when differences are included. This need not be true. As we demonstrate, differences are not innocuous noise, but can fundamentally change the nature of a game. Even small amounts ofvariability can stabilize cooperation by, for example, maintaining the need to deal with cheaters. Differences promote the need to learn about others in an interaction, leading to contingent behaviour that can reduce conflict, and to negotiated outcomes that may or may not be more cooperative than unconditional actions. Once there are mechanisms such as mutation and environmental influences that maintain variation within populations, whether cooperation evolves may depend on the variation in the cooperativeness trait. Variation means that it may be worth taking a chance that a partner is cooperative by being cooperative. When there are markets, so that individuals can break off interactions to seek a better partner, variation promotes choosiness and hence penalizes those uncooperative individuals, who are rejected. Variation promotes the need to monitor the previous behaviour of others, and once this social sensitivity exists, the need to maintain a good reputation can promote cooperation. © 2010 The Royal Society.

The present investigation deals with the variable use of referential devices expressing generic or speaker-oriented reference in a corpus of sociolinguistic interviews where Spanish informants talk about their studies and work experience. The analysis focuses on impersonal second person singulars (2SG-imp), which are compared with the first person singular (1SG) and plural (1PL), uno 'one' and reflexive-based impersonal constructions. Quantitative analysis shows that age, gender and familiarity between the speakers are significant factors in accounting for the inter-speaker variation. There is a negative correlation between age and 2SG-imp usage and a positive correlation between age and 1PL usage, and female speakers use both constructions more than men. I discuss the relation of the choice of referring expressions and the expression of intersubjectivity in the interviews. Qualitative analysis of the interview content suggests that there is a connection between the choice of referential devices and generational differences in the choice of individual vs. collective perspective and the inclusion of the addressee. © 2016 Elsevier B.V.

Britton T.,University of Stockholm
Mathematical Biosciences | Year: 2010

This paper is a survey paper on stochastic epidemic models. A simple stochastic epidemic model is defined and exact and asymptotic (relying on a large community) properties are presented. The purpose of modelling is illustrated by studying effects of vaccination and also in terms of inference procedures for important parameters, such as the basic reproduction number and the critical vaccination coverage. Several generalizations towards realism, e.g. multitype and household epidemic models, are also presented, as is a model for endemic diseases. © 2010 Elsevier Inc.

Hall A.M.,University of St. Andrews | Ebert K.,University of Stockholm
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2013

Allochthonous Cenozoic microfossils have been reported from Late Pleistocene lake and mire host sediments across an area of >30,000km2 in northern Finland. Two main groups of microfossils are recognised: Palaeogene marine diatoms, silicoflagellates and ebridians that include taxa from around the time of the Palaeocene-Eocene Thermal Maximum and Pliocene to early Pleistocene freshwater diatoms. The presence of these microfossils has been regarded as evidence that Eocene marine and late Neogene freshwater sediments formerly existed on the shield surface. Both groups have been referred to frequently in reconstructions of the sea level, tectonic and erosion history of the northern Fennoscandian shield. The questions raised by the presence of allochthonous Cenozoic microfossils in northern Finland are, however, strongly resonant of the debate over the biota, origin and age of the Pliocene Sirius Group in Antarctica where competing hypotheses have been put forward of local deposition and reworking versus distant wind transport of marine diatoms from the continental shelf.This review explores alternative origins for the allochthonous Cenozoic microfossils in northern Finland. Local reworking of Palaeogene marine sediments during Pleistocene glaciation is unlikely, as no source rocks of Palaeogene age are known from the shield surface or from surrounding sedimentary basins in the Baltic and White Sea. Moreover, at all sites except Akanvaara, the marine diatom taxa cover wide age ranges and occur only as minor components in diatom assemblages that are dominated by Quaternary freshwater taxa. Local reworking of Pliocene-Pleistocene freshwater diatoms is, however, compatible with the widespread survival of pre-Pleistocene deep weathering although no in situ or unmixed, ice-rafted Pliocene-Pleistocene lacustrine sediment has yet been found. An alternative origin for the marine Palaeogene microfossils by distant wind transport is proposed. In this hypothesis, Palaeogene diatomites on the Barents Sea shelf were exposed to deep glacial and fluvioglacial erosion during the Pliocene and Early Pleistocene and in low sea level stages of the Middle and Late Pleistocene. Intense wind action acting on comminuted mudstones on outwash plains carried dust including microfossils into northern Fennoscandia to be deposited by rain-out in lakes and wetlands. This material may have been later further recycled by glacial and meltwater transport and more localised wind action, processes that also may help to account for the distribution of Eemian marine diatoms well beyond Eemian shorelines. The distant wind transport hypothesis implies that the presence of marine Palaeogene diatoms on the shield surface in northern Finland cannot be regarded as vestiges of former marine sediments and so do not constrain the tectonic and geomorphic history of the northern Fennoscandian shield in the Cenozoic. © 2013 Elsevier B.V.

This is a review of the evidence on seedling recruitment patterns in clonal forest plants, based on a previously used typology in which the occurrence of seedling recruitment is related to the performance of adult genets: repeated seedling recruitment (RSR), initial seedling recruitment (ISR), recruitment at windows of opportunity (RWO) and systematic spatial variation in seedling dynamics among local populations (RSR/ISR). Generally, seedling recruitment in clonal populations is common and the majority of species have the capacity to recruit within established adult populations. All four recruitment patterns are documented in studies, which include both genetic and demographic evidence that support the existence of a range of variation in seedling recruitment among clonal plants. However, itissuggested that this four-category typology should be replaced by a framework based on two continuously varying factors: the degree of niche overlap between juvenile and adult life cycle stages (uncoupling of juvenile and adult niches implies "niche shifts") and of seed limitation during recruitment. This creates a hypothetical continuous space within which all recruitment patterns are placed and stimulates research to focus on identifying mechanisms determining the variation in the recruitment of clonal plants. Some further implications of this framework are briefly discussed.

Theorell T.,University of Stockholm
Advances in Psychosomatic Medicine | Year: 2012

Despite the fact that there is an extensive scientific literature regarding the importance of exposure to psychosocial stressors, the assessment of such stressors is often neglected in clinical work. The present review summarizes the scientific literature on critical life changes and work-related stressors. Particular emphasis has been on somatic outcomes and physiological processes that have been shown to be affected by exposure to stressors. Although the relationships are highly complex, it could be concluded that exposure to stressors may often determine the onset of many illnesses. Standardized well-functioning assessment instruments that could be used in clinical practice exist and should be used. Copyright © 2012 S. Karger AG, Basel.

Reed D.C.,University Utrecht | Slomp C.P.,University Utrecht | Gustafsson B.G.,University of Stockholm
Limnology and Oceanography | Year: 2011

The present study examines oxygen and phosphorus dynamics at a seasonally hypoxic site in the Arkona basin of the Baltic Sea. A coupled benthic-pelagic reactive-transport model is used to describe the evolution of bottomwater solute concentrations, as well as pore-water and sediment profiles. Aerobic respiration dominates remineralization, with iron reduction, denitrification, and sulphate reduction playing secondary roles, while other pathways are negligible. Sediments represent a significant oxygen sink chiefly due to the aerobic degradation of organic matter, as well as nitrification and iron oxyhydroxide precipitation. Most phosphorus deposited in sediments is in organic matter, yet cycling is dominated by iron-bound phosphorus due to rapid dissimilatory iron reduction coupled with aerobic iron oxyhydroxide formation. Sustained hypoxia results in an initial decrease in sediment phosphorus content due to dissolution of phosphorus-bearing iron oxyhydroxides, resulting in a pulse of phosphate to overlying waters. Although an organic-rich layer is formed under low-oxygen conditions, enhanced remineralization of organic phosphorus relative to organic carbon tempers sedimentary phosphorus accumulation. Upon reoxygenation of bottom waters after a decade of sustained hypoxia, oxygen concentrations do not immediately achieve values observed prior to hypoxia because the organic-rich layer creates a higher benthic oxygen demand. Artificial reoxygenation of bottom waters leads to a substantial increase in the iron-bound phosphorus pool; the total phosphorus content of the sediment, however, is unaffected. A relapse into hypoxia would consequently produce a large pulse of phosphate to the overlying waters potentially exacerbating the situation. © 2011, by the American Society of Limnology and Oceanography, Inc.

Sorlin S.,KTH Royal Institute of Technology | Sorlin S.,University of Stockholm
Environmental Science and Policy | Year: 2013

This article examines the concepts 'environment' and 'expertise'. It is argued that these concepts, while having long and diverse individual histories, acquired new meaning through a process of mutual co-production which occurred largely in the period 1920-1960, thus significantly preceding the common understanding of environmentalism as a phenomenon emerging in the 1960s. It is further argued that environmental expertise is much predicated on natural science in a range of fields that were integrated into a comprehensive understanding scaling upwards from the local to the global. Quantitative analysis, observing, measuring, and monitoring rates of change of a growing set of indicators were other key features of this emerging understanding of the environmental. Yet another key aspect was the self-proclaimed ability of environmental expertise to predict rates and directions of current and, crucially, future changes of global environmental conditions, increasingly assuming that these changes were largely of human origin. In addition to thus presenting a brief history of environmental expertise the article also makes the point that the environmental was, despite changed by human action, essentially regarded as something that did not in itself belong to the human or the social and thus the implicit prerogative of the natural sciences. The article argues, on the contrary, that there is solid historical evidence to suggest that 'environment' should also, perhaps primarily, be understood as a social concept, or rather as an extension of the social into nature. As conventional environmental expertise has failed to provide the advice needed to question the driving forces behind environmental degradation and lack of sustainability it is here instead suggested that environmental expertise be fundamentally reconfigured to include the social sciences and humanities, and that concerted research efforts are directed to the understanding of the formation of environmental expertise. © 2013.

Schmidt O.,University of Adelaide | Soderhll K.,Uppsala University | Faye I.,University of Stockholm
Annual Review of Entomology | Year: 2010

The recognition and inactivation of toxins and pathogens are mediated by a combination of cell-free and cellular mechanisms. A number of soluble and membrane-bound pattern recognition molecules interact with elicitors to become involved in both cell-free inactivation as well as cellular uptake reactions. Here we describe the possible recognition and effector function of key arthropod immune proteins, such as peroxinectin, hemolin, and hemomucin, as an outcome of changes in adhesiveness, which drive self-assembly reactions leading to cell-free coagulation and cellular uptake reactions. The fact that some of these proteins are essential for immune and developmental functions in some species, but are not found in closely related species, may point to the existence of multiprotein assemblies, which are conserved at the mechanistic level and can function with more than one combination of protein constituents. © 2010 by Annual Reviews All rights reserved.

Edman J.,University of Stockholm | Stenius K.,Finnish National Institute for Health and Welfare
International Journal of Drug Policy | Year: 2014

Background: The drug and alcohol fields are characterised by continuous contestations of key concepts and the competing uses of concepts by various actors, in different geographies and over time. This study investigates the political processes leading to legislation enabling coercive treatment of (non-psychotic) drug users in Finland and Sweden from the 1950s until the early 1980s. The drug treatment policies are analysed through conceptual changes and innovations. Methods: The article analyses conceptual discussions in public reports in Finland and Sweden, focusing on the work preceding the first legislations where both alcohol and drug treatment were included (in Finland 1961, in Sweden 1982). Theories from conceptual history are applied. Results: The Finnish and Swedish discussions carry arguments from two periods of the Nordic welfare state: in an early development stage and a fragile situation in Finland, and in a more mature and affluent time in Sweden. The paternalistic arguments vary over time and between countries. Still, in both countries and time periods, the view of the drug problem as a youth issue, as particularly enslaving and on society's obligation to protect drug using individuals from damaging their future give enough motivation for coercive treatment. The conceptual work included avoidance of certain terms but in other cases, a broadening of their meaning, to adopt them to the political goals. Conclusion: Close analyses of conceptual history can reveal new features of drug policy struggles and show how central concepts in drugs and alcohol field are continuously contested. © 2013 Elsevier B.V.

Edman J.,University of Stockholm
Drugs and Alcohol Today | Year: 2013

Purpose: This article seeks to investigate the ideological visions embedded in the political formulation of the Swedish drug problem and in the bureaucratic management of the Swedish drug treatment services during the years 1960-2000. Design/methodology/approach: The empirical basis for the analysis consists mainly of parliamentary material from the Swedish Parliament (403 parliamentary bills, 66 government bills, 198 parliamentary records, 14 government letters and 159 standing committee statements) as well as archival materials produced in the application process of 73 aspiring treatment homes from the years 1960-2001. The empirical material is partly analyzed from a theoretical understanding of political consensus as a doxa and political debate as permeated by naturalizing ideologies. Findings: The article examines drug consumption as a political problem and its ideological undertones. It shows how drugs and drug consumption often have been subordinate in problem descriptions that have fulfilled other political purposes. Worries about politically radical youth, foreign religions or incomprehensible music have been understood as a drug problem. In the Swedish parliament the drug problem has been described in terms of capitalist class oppression, Americanism or cultural superficiality. Modernity, urbanization and industrialization have also been criticized in the name of the drug problem. In the treatment centres and within the ruling bureaucracy it was also elucidated that the drug problem was an ideological problem. The effective treatment method has been elusive, but the effective method has also played second fiddle in the choice of treatment solutions. Other values have been awarded, such as rural romanticism, Swedishness, solidarity and diligence. Individualism, Americanism and profit making have also been opposed within the ideological treatment sector. At the end of the research period such assessments however became subordinate to an overarching ideological quest to make substance abuse treatment a market among others. Social implications: A focus on the ideological content both in political discussions and bureaucratic management might enrich the understanding of both politics and bureaucracy as well as the formulation of the drug problem and the suggested solutions. Ideology is not the opposite of facts or evidence-based solutions; ideology permeates every aspect of problem formulations and solutions. To recognize the drug issue's ideological disposition should therefore not be seen as way of avoiding discussions about the actual dilemma with drugs, it is rather an opportunity to seriously start a discussion on how to solve the problem. Originality/value: The analyzing of naturalized and apparently self-evident ideology as part of the rational argument rather than its very opposite would be useful both for further research on the topic as well as for deepening the democratic discussions on, for instance, evidence-based methods within the drug treatment services. © Emerald Group Publishing Limited.

Eilola K.,Swedish Meteorological and Hydrological Institute | Martensson S.,Swedish Meteorological and Hydrological Institute | Meier H.E.M.,Swedish Meteorological and Hydrological Institute | Meier H.E.M.,University of Stockholm
Geophysical Research Letters | Year: 2013

In a warming future climate, the sea ice cover is expected to decrease, with very likely large consequences for the marine ecosystem. We investigated the impact of future sea ice retreat on the Baltic Sea biogeochemistry at the end of the century, using an ensemble of regionalized global climate simulations. We found that the spring bloom will start by up to one month earlier and winds and wave-induced resuspension will increase, causing an increased transport of nutrients from the productive coastal zone into the deeper areas. The internal nutrient fluxes do not necessarily increase because they also depend on oxygen and temperature conditions of the bottom water. Winter mixing increases in areas having reduced ice cover and in areas having reduced stratification due to increased freshwater supply. The reduced sea ice cover therefore partly counteracts eutrophication because increased vertical mixing improves oxygen conditions in lower layers. © 2013. American Geophysical Union. All Rights Reserved.

Andren A.,University of Stockholm
World Archaeology | Year: 2013

The question of cult continuity from pagan 'temples' to Christian churches in Scandinavia is a classic issue in archaeology and history. In this paper the discussion is surveyed and new perspectives are outlined, based on the ritual differences between the two religious traditions. Churches were located in relation not so much to pagan ritual buildings as to different elements in multi-focused pagan ritual landscapes, for instance burial grounds. This means that the spatial patterns varied between different parts of Scandinavia. © 2013 Copyright Taylor and Francis Group, LLC.

Melvin T.M.,University of East Anglia | Grudd H.,University of Stockholm | Briffa K.R.,University of East Anglia
Holocene | Year: 2013

We describe the analysis of existing and new maximum-latewood-density (MXD) and tree-ring width (TRW) data from the Torneträsk region of northern Sweden and the construction of 1500 year chronologies. Some previous work found that MXD and TRW chronologies from Torneträsk were inconsistent over the most recent 200 years, even though they both reflect predominantly summer temperature influences on tree growth. We show that this was partly a result of systematic bias in MXD data measurements and partly a result of inhomogeneous sample selection from living trees (modern sample bias). We use refinements of the simple Regional Curve Standardisation (RCS) method of chronology construction to identify and mitigate these biases. The new MXD and TRW chronologies now present a largely consistent picture of long-timescale changes in past summer temperature in this region over their full length, indicating similar levels of summer warmth in the medieval period (MWP, c. ce 900-1100) and the latter half of the 20th century. Future work involving the updating of MXD chronologies using differently sourced measurements may require similar analysis and appropriate adjustment to that described here to make the data suitable for the production of un-biased RCS chronologies. The use of 'growth-rate' based multiple RCS curves is recommended to identify and mitigate the problem of 'modern sample bias'. © The Author(s) 2012.

Hannachi A.,University of Stockholm | Turner A.G.,University of Reading
Geophysical Research Letters | Year: 2013

It is known that the empirical orthogonal function method is unable to detect possible nonlinear structure in climate data. Here, isometric feature mapping (Isomap), as a tool for nonlinear dimensionality reduction, is applied to 1958-2001 ERA-40 sea-level pressure anomalies to study nonlinearity of the Asian summer monsoon intraseasonal variability. Using the leading two Isomap time series, the probability density function is shown to be bimodal. A two-dimensional bivariate Gaussian mixture model is then applied to identify the monsoon phases, the obtained regimes representing enhanced and suppressed phases, respectively. The relationship with the large-scale seasonal mean monsoon indicates that the frequency of monsoon regime occurrence is significantly perturbed in agreement with conceptual ideas, with preference for enhanced convection on intraseasonal time scales during large-scale strong monsoons. Trend analysis suggests a shift in concentration of monsoon convection, with less emphasis on South Asia and more on the East China Sea. Key Points Paper demonstrates bimodality in monsoon intraseasonal variability Methodology combines both the nonlinearity and high dimensionality of monsoon Suggests enhanced predictability of active/break monsoon phases variability. ©2013. American Geophysical Union. All Rights Reserved.

Green J.A.M.,Bangor University | Nycander J.,University of Stockholm
Journal of Physical Oceanography | Year: 2013

The conversion of barotropic to baroclinic tidal energy in the global abyssal ocean is calculated using three different formulations. The calculations are done both "offline,"that is, using externally given tidal currents to estimate the energy conversion, and "online,"that is, by using the formulations to parameterize linear wave drag in a prognostic tidal model. All three schemes produce globally integrated offline dissipation rates beneath 500-m depth of;0.6-0.8TWfor theM2 constituent, but the spatial structures vary significantly between the parameterizations. Detailed investigations of the energy transfer in local areas confirm the global results: there are large differences between the schemes, although the horizontally integrated conversion rates are similar. The online simulations are evaluated by comparing the sea surface elevation with data from the TOPEX/Poseidon database, and the error is then significantly lower when using the parameterization provided by Nycander than with the other two parameterizations examined. © 2013 American Meteorological Society.

Frank M.G.,University of Pennsylvania | Cantera R.,University of Stockholm
Trends in neurosciences | Year: 2014

Sleep is widely believed to play an essential role in synaptic plasticity. However, the precise mechanisms governing this presumptive function are largely unknown. There is also evidence for independent circadian oscillations in synaptic strength and morphology. Therefore, synaptic changes observed after sleep reflect interactions between state-dependent (e.g., wake versus sleep) and state-independent (circadian) processes. In this review we consider how sleep and biological clocks influence synaptic plasticity. We discuss these findings in the context of current plasticity-based theories of sleep function and propose a new model that integrates circadian and brain-state influences on synaptic plasticity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sundberg M.,University of Stockholm
Science Technology and Human Values | Year: 2012

Numerical simulations have come to be widely used in scientific work. Like experiments, simulations generate large quantities of numbers (output data) that require analysis and constant concern with uncertainty and error. How do simulationists convince themselves, and others, about the credibility of output? The present analysis reconstructs the perspectives related to performing numerical simulations, in general, and the situations in which simulationists deal with uncertain output, in particular. Starting from a distinction between idealized and realistic simulations, the paper presents the principal methods of evaluation in relation to these practices and how different audiences expect different methods. One major challenge in interpreting output data is to distinguish between "real" and "numerical" effects. Within the practice of idealized simulations, simulationists hold the underlying model accountable for results that manifest "real" effects, but because "numerical" and "real" effects cannot be distinguished on the basis of what they derive from, attempted causal explanations are rather justifications for their conclusions. At the same time, simulationists' explanations are part and parcel of their contradictory perspectives, according to which they believe in simulations largely due to the underlying model, while painfully recognizing everything they have to add to make computations doable on the basis of this model. © SAGE Publications 2012.

Roquet F.,University of Stockholm
Journal of Physical Oceanography | Year: 2013

The concept of available potential energy is supposed to indicate which part of the potential energy is available to transform into kinetic energy. Yet it is impossible to obtain a unique definition of available potential energy for the real ocean because of nonlinearities of the equation of state, rendering its usefulness largely hypothetical. In this paper, the conservation of energy is first reformulated in terms of horizontal anomalies of density and pressure for a simplified ocean model using the Boussinesq and hydrostatic approximations. This framework introduces the concept of "dynamical potential energy," defined as the horizontal anomaly of potential energy, to replace available potential energy. Modified conservation equations are derived that make it much simpler to identify oceanic power input by buoyancy and mechanical forces. Closed budgets of energy are presented for idealized circulations obtained with a general circulation model, comparing spatial patterns of power inputs generated by wind and thermal forcings. Finally, a generalization of the framework to compressible fluids is presented, opening the way to applications in atmosphere energetics. © 2013 American Meteorological Society.

Mannervik B.,University of Stockholm
The Journal of biological chemistry | Year: 2012

Uncle Folke inspired me to become a biochemist by demonstrating electrophoresis experiments on butterfly hemolymph in his kitchen. Glutathione became the subject for my undergraduate project in 1964 and has remained a focal point in my research owing to its multifarious roles in the cell. Since the 1960s, the multiple forms of glutathione transferase (GST), the GSTome, were isolated and characterized, some of which were discovered in our laboratory. Products of oxidative processes were found to be natural GST substrates. Examples of toxic compounds against which particular GSTs provide protection include 4-hydroxynonenal and ortho-quinones, with possible links to the etiology of Alzheimer and Parkinson diseases and other degenerative conditions. The role of thioltransferase and glutathione reductase in the cellular reduction of disulfides and other oxidized forms of thiols was clarified. Glyoxalase I catalyzes still another glutathione-dependent detoxication reaction. The unusual steady-state kinetics of this zinc-containing enzyme initiated model discrimination by regression analysis. Functional properties of the enzymes have been altered by stochastic mutations based on DNA shuffling and rationally tailored by structure-based redesign. We found it useful to represent promiscuous enzymes by vectors or points in multidimensional substrate-activity space and visualize them by multivariate analysis. Adopting the concept "molecular quasi-species," we describe clusters of functionally related enzyme variants that may emerge in natural as well as directed evolution.

Soderberg E.,University of Stockholm
Nucleus (Austin, Tex.) | Year: 2012

We have raised antibodies against the profilin of Chironomus tentans to study the location of profilin relative to chromatin and to active genes in salivary gland polytene chromosomes. We show that a fraction of profilin is located in the nucleus, where profilin is highly concentrated in the nucleoplasm and at the nuclear periphery. Moreover, profilin is associated with multiple bands in the polytene chromosomes. By staining salivary glands with propidium iodide, we show that profilin does not co-localize with dense chromatin. Profilin associates instead with protein-coding genes that are transcriptionally active, as revealed by co-localization with hnRNP and snRNP proteins. We have performed experiments of transcription inhibition with actinomycin D and we show that the association of profilin with the chromosomes requires ongoing transcription. However, the interaction of profilin with the gene loci does not depend on RNA. Our results are compatible with profilin regulating actin polymerization in the cell nucleus. However, the association of actin with the polytene chromosomes of C. tentans is sensitive to RNase, whereas the association of profilin is not, and we propose therefore that the chromosomal location of profilin is independent of actin.

Chechi K.,Laval University | Nedergaard J.,University of Stockholm | Richard D.,Laval University
Obesity Reviews | Year: 2014

Summary: During the 11th Stock Conference held in Montreal, Quebec, Canada, world-leading experts came together to present and discuss recent developments made in the field of brown adipose tissue biology. Owing to the vast capacity of brown adipose tissue for burning food energy in the process of thermogenesis, and due to demonstrations of its presence in adult humans, there is tremendous interest in targeting brown adipose tissue as an anti-obesity tissue in humans. However, the future of such therapeutic approaches relies on our understanding of the origin, development, recruitment, activation and regulation of brown adipose tissue in humans. As reviewed here, the 11th Stock Conference was organized around these themes to discuss the recent progress made in each aspect, to identify gaps in our current understanding and to further provide a common groundwork that could support collaborative efforts aimed at a future therapy for obesity, based on brown adipose tissue thermogenesis. © 2013 International Association for the Study of Obesity.

Duit A.,University of Stockholm | Feindt P.H.,Wageningen University | Meadowcroft J.,Carleton University
Environmental Politics | Year: 2016

‘Bringing the state back in’ to research on comparative, inter-, and trans-national environmental politics and policy will contribute to better understanding of the limits and prospects of contemporary approaches to environmental politics and the overall evolution of contemporary states once environmental issues become central. The rationale for the state as an analytical perspective in environmental policy and politics is explained, and an empirically oriented concept of the environmental state is introduced, along with a tentative sketch of its evolution in historical perspective. A research agenda on the environmental state is mapped out, centring around variation and convergence in environmental states across space and time; the political/economic dynamics of contemporary environmental states; and inter-linkages among environmental problems, the constitution of political communities, and the functioning of the public power. In conclusion, the ways in which the contributions to this volume address that research agenda are introduced. © 2015 Taylor & Francis.

Rindstedt C.,University of Stockholm
Child: Care, Health and Development | Year: 2014

Background: This article explores how children use fantasy, play, and coping (imaginal coping) in order to handle chronic illness. Imaginal coping, as a theoretical construct, is defined as the use of imagination to deal with the hardships of illness. The overarching aim has been to investigate the various ways in which categories of staff members (doctors, nurses, play therapists, and hospital clowns) and parents support children in their coping. Focus has thus been on collaborative or interactive aspects of playful coping. Method: A large proportion of the data collected consists of 93h of video-recorded interactions between children, parents and staff. The collection of data involved fieldwork carried out with the use of a video ethnographic method, making it possible thereby to analyse and work with data in greater detail. For more than one year, five children with leukaemia were followed as each made their regular visits to a children's cancer clinic in a children's hospital in Sweden. Results: Collaborative storytelling, humorous treatment practices, playful rituals, as well as role-reversal play, were all types of events involving staff-child collaboration and creative improvisation. Conclusions: Staff, along with parents, played a significant role in the coping process. In various ways, the staff members helped the parents to respond to their children in ways adaptive for coping. It can be seen that imaginal coping is a highly interactional business. In this study it is shown that parents socialize coping; this is sometimes undertaken explicitly, for example, through coaching (in the form of instructions or suggestions) and teaching. But often it is achieved through modelling or intent participation, with the child observing staff members' treatment practices. © 2013 John Wiley & Sons Ltd.

Duit A.,University of Stockholm
Environmental Politics | Year: 2016

The primary task for the environmental state is to address problems related to the market’s externalisation of environmental costs. It has four main resources at its disposal: regulation, redistribution, organisation, and knowledge generation. The way these four resources are deployed make up a state’s environmental governance arrangements. Using data on environmental regulation, taxes, public administrations, and knowledge production from 28 countries, and a hierarchical cluster analysis, four different types of environmental states are identified: established, emerging, partial, and weak. This is followed by some suggestions for further research on the environmental state in a comparative perspective. © 2015 Taylor & Francis.

Hagman M.,University of Stockholm
Communicative and Integrative Biology | Year: 2010

In a recent paper,1 we showed that recurrent exposure to alarm pheromones reduced development time and size at metamorphosis in larval cane toads (Bufo marinus). Subsequent measurements of post-metamorphic toads revealed larger parotoid glands relative to body size and increased amounts of bufalin (a toxic bufodienalide) in animals from the experimental treatment, suggesting increased investment in chemical defenses. These findings are of interest for evolutionary theory. But the study was also part of a larger conservation-based research program of which this pheromone work was an important component in the development of a management strategy for reducing the ecological impact of invasive cane toads in Australia. For example, our study1 aimed to quantify biochemical and life-history effects as well as assess the likely longterm impact of pheromone exposure on toads. In this addendum, I discuss the conservation potential of our research, with emphasis on exploiting alarm pheromones to induce viability reducing lifehistory shifts. © 2010 Landes Bioscience.

Wheat C.W.,University of Stockholm | Wahlberg N.,University of Turku
Trends in Ecology and Evolution | Year: 2013

Phylogenomic advances provide more rigorous estimates for the timing of evolutionary divergences than previously available (e.g., Bayesian relaxed-clock estimates with soft fossil constraints). However, because many family-level clades and higher, as well as model species within those clades, have not been included in phylogenomic studies, the literature presents temporal estimates likely harboring substantial errors. Blindly using such dates can substantially retard scientific advancement. We suggest a way forward by conducting analyses that minimize prior assumptions and use large datasets, and demonstrate how using such a phylogenomic approach can lead to significantly more parsimonious conclusions without a good fossil record. We suggest that such an approach calls for research into the biological causes of conflict between molecular and fossil signatures. © 2013 Elsevier Ltd.

In this paper conventional X-ray analysis of cattle metapodials is used to study the age structure of slaughtered cattle at Eketorp ringfort on the island of Öland, Sweden. The X-ray analyses suggest that several animals in both phases were slaughtered aged 4-8 years. More oxen/bulls than cows reached the advanced age of over 8 years, yet in phase III more oxen/bulls seem to have been slaughtered between the ages of 2 and 8 years. These differences may reflect a change in demand for meat related to the character of the site. The results also show a correlation between metapodials with a pathology connected to biomechanical stress and older animals. This suggests that male cattle were used both in meat production and as draught animals. Asymmetry in male metatarsals such as distal broadening of the lateral part of the medial trochlea was visible on the X-ray images. The bone element also indicates a denser outer cortex of the medial diaphysis in comparison to the inner medulla. This could be the result of repetitive mechanical stress. Two metatarsals from cows were documented with distal asymmetry indicating that cows were also used as working animals. Bone elements with changes in the articular surfaces were more common in metapodials from cows with an X-ray age of over 3-4 years. These results highlighted the slaughter age difference between oxen/bulls and cows, enabling a better understanding of animal husbandry and the selection of draught cattle at Eketorp ringfort. © 2015 Ylva Telldahl.

Eden M.,University of Stockholm
Annual Reports on NMR Spectroscopy | Year: 2015

Aluminosilicate glasses are of great geological and technological importance. Significant efforts have been spent for enhancing the insight into their structures, where magic-angle-spinning (MAS) NMR that exploits the spin-5/2 27Al as probe nucleus constitutes one widely utilized option. We review the application of basic 27Al NMR experimentation for studying primarily the short-range (≲0.3 nm) structure of aluminosilicate glasses, emphasizing practical aspects of performing MAS and triple-quantum MAS NMR experiments, as well as options for data analysis to extract 27Al NMR parameters and quantifying AlOp populations. We illustrate the strengths and weaknesses of routine 27Al NMR for investigating aluminosilicate glasses, including its development over time. While parts of the text apply generally to MAS NMR targeting half-integer spins as structural probes in crystalline as well as amorphous materials, the focus remains on 27Al NMR applications to aluminosilicate glasses, whose basic structural features are outlined together with a survey of the most central research problems in the field. By providing both in-depth discussions about the building blocks of aluminosilicate glasses while assuming a modest background knowledge of the reader about MAS NMR and glass structure, we hope that the presentation will appeal to a broad audience, encompassing both experienced researchers in solid-state NMR or glass structures, as well as to beginners in either area. © 2015 Elsevier Ltd.

The article analyses the legitimation processes of two transnational regulatory partnerships-the Equator Principles (EP) and the Principles for Responsible Investments (PRI)-providing guidelines for global financial institutions to take societal responsibility in their financial decisions. By using the theoretical concept of organizational legitimation it is argued that partnerships seek legitimacy from their audiences by constructing their boundaries (identity), coordinating activities (hierarchy), and producing goals (rationality). The empirical analysis shows that the EP and the PRI follow classical strategies of organizational legitimation. They reflect the norm of being societally responsible and create an agency that can be accountable for conformity with standards on environmental, social, and governance issues. The article pinpoints, however, two dilemmas for the EP and the PRI that stem from the global trend of governing by numbers, resulting in an expectations gap between the signatories and external NGOs. Those dilemmas could instead lead to a delegitimation of the partnerships. © 2014 Taylor & Francis.

Kamerlin S.C.L.,University of Southern California | Kamerlin S.C.L.,University of Stockholm | Vicatos S.,University of Southern California | Dryga A.,University of Southern California | Warshel A.,University of Southern California
Annual Review of Physical Chemistry | Year: 2011

Recent years have witnessed an explosion in computational power, leading to attempts to model ever more complex systems. Nevertheless, there remain cases for which the use of brute-force computer simulations is clearly not the solution. In such cases, great benefit can be obtained from the use of physically sound simplifications. The introduction of such coarse graining can be traced back to the early usage of a simplified model in studies of proteins. Since then, the field has progressed tremendously. In this review, we cover both key developments in the field and potential future directions. Additionally, particular emphasis is given to two general approaches, namely the renormalization and reference potential approaches, which allow one to move back and forth between the coarse-grained (CG) and full models, as these approaches provide the foundation for CG modeling of complex systems. © 2011 by Annual Reviews. All rights reserved.

Aims: The aims of this study were to study whether alcohol-related self-reported problems follow the same pattern of changes in alcohol consumption in southern Sweden, assumed to be affected by a decrease in Danish spirits tax and by an increase in Swedish travellers' import quotas, and to study whether the results obtained for southern and northern Sweden follow the predictions of Skog's theory of collectivity of drinking cultures. Methods: Analysis was carried out on a sample from the Swedish general population from southern and northern Sweden separately. Two indices such as impaired self-control/dependent behaviour and extrinsic problems for alcohol-related problems were computed and analysed in terms of sex, age, income and alcohol consumption level. Results: Although there were no huge changes in the number of persons reporting alcohol-related problems, the general trend in data for various subpopulations was a decrease in the southern site and an increase in the northern site. In the northern site, the increase in alcohol consumption among men also showed an increase in alcohol-related problems. However, various population subgroups changed in different directions and did not move in concert over the population distribution. Conclusions: Analysis confirmed that alcohol-related problems, according to the two indices used, followed a similar pattern to alcohol consumption, but less divergent. A version of Skog's theory applied on alcohol-related problems could not confirm that alcohol-related problems did not change collectively within the population. © The Author 2010. Published by Oxford University Press on behalf of the Medical Council on Alcohol.

Objectives. I examined associations between evacuation of Finnish children to temporary foster care in Sweden during World War II and all-cause mortality between ages 38 and 78 years. Methods. I used a Cox proportional hazards model to estimate mortality risk according towhether the individualwas evacuated during childhood or not. I used within-sibling analysis to control for all unobserved socioeconomic and genetic characteristics shared among siblings. Individual-level data for Finnish cohorts born in 1933 to 1944 were derived from wartime government records, Finnish census data from 1950 and 1970, and death cause registry from 1971 to 2011. Results. I found no statistically significant association between evacuation and all-cause mortality when all exposed individuals were included in the analysis. However, subgroup analysis showed that men evacuated before age 4 years had a 1.31 higher mortality risk (95% confidence interval = 1.01, 1.69) than their nonevacuated counterparts. Conclusions. In the aggregate, individuals do not have elevated mortality risk as a consequence of foster care during early childhood owing to the onset of sudden external shocks (e.g., wars).

Ljusberg A.-L.,University of Stockholm
Child: Care, Health and Development | Year: 2011

Background An increasing number of segregating solutions (e.g. remedial classes) can be seen in Swedish schools. The aim of this article is to stress how children describe why they attend a remedial class and what it means to be a pupil in that setting. Methods The data collection consists of semi-structured interviews with 10 pupils between 10 and 12 years old attending 10 different remedial classes because they had been attributed with having concentration difficulties or diagnosed with attention deficit/hyperactivity disorder. The content of the interviews was described and analysed in relation to the classroom context. The socio-cultural perspective is used as a screen to describe and understand the children's comments about attending remedial class. Results and conclusions All interviews with the children indicate that they are carriers of their schools' compensatory perspective. This means that they are fully aware of the fact that they are regarded as difficult, with annoying and problematic behaviour, deviating from pupils' in general. The remedial class creates social difficulties for the children; they see themselves as deviant, they lose old friends and there are limited possibilities of establishing new friendship in remedial classes. © 2011 Blackwell Publishing Ltd.

Landberg J.,University of Stockholm
European Addiction Research | Year: 2010

Aims: To estimate to what extent injury mortality rates in 6 Eastern European countries are affected by changes in population drinking during the post-war period. Data and Methods: The analysis included injury mortality rates and per capita alcohol consumption in Russia, Belarus, Poland, Hungary, Bulgaria and the former Czechoslovakia. Total population and gender-specific models were estimated using auto regressive integrated moving average time-series modelling. Results: The estimates for the total population were generally positive and significant. For Russia and Belarus, a 1-litre increase in per capita consumption was associated with an increase in injury mortality of 7.5 and 5.5 per 100,000 inhabitants, respectively. The estimates for the remaining countries ranged between 1.4 and 2.0. The gender-specific estimates displayed national variations similar to the total population estimates although the estimates for males were higher than for females in all countries. Conclusions: The results suggest that changes in per capita consumption have a significant impact on injury mortality in these countries, but the strength of the association tends to be stronger in countries where intoxication-oriented drinking is more common. © 2009 S. Karger AG, Basel.

Hohna S.,University of Stockholm | Drummond A.J.,University of Auckland
Systematic Biology | Year: 2012

Increasingly, large data sets pose a challenge for computationally intensive phylogenetic methods such as Bayesian Markov chain Monte Carlo (MCMC). Here, we investigate the performance of common MCMC proposal distributions in terms of median and variance of run time to convergence on 11 data sets. We introduce two new Metropolized Gibbs Samplers for moving through "tree space." MCMC simulation using these new proposals shows faster average run time and dramatically improved predictability in performance, with a 20-fold reduction in the variance of the time to estimate the posterior distribution to a given accuracy. We also introduce conditional clade probabilities and demonstrate that they provide a superior means of approximating tree topology posterior probabilities from samples recorded during MCMC. © 2011 The Author(s).

Westermark A.,University of Stockholm
International Journal of Oral and Maxillofacial Surgery | Year: 2010

12 patients underwent temporomandibular joint (TMJ) reconstruction with Biomet total joint prostheses. Indications for TMJ reconstruction included ankylosis, rheumatoid arthritis, degenerative joint disease and condylar resorption. Five patients had unilateral procedures, seven had bilateral. The follow-up ranged between 2 and 8 years. Amongst the ankylotic patients the mean jaw-opening capacity increased from 3.8 mm preoperatively to 30.2 mm 1 year after surgery, and in most of those patients the opening capacity remained stable over the years. The other patients maintained a mean opening capacity of more than 35 mm. Joint related pain and interference with eating were eliminated after TMJ reconstruction. There were no permanent facial nerve disturbance, no postoperative infections and no device related complications. The outcome supports prosthetic TMJ reconstruction as a useful treatment modality in patients with advanced TMJ disease. © 2010 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Belyaev I.Y.,Cancer Research Institute | Belyaev I.Y.,University of Stockholm
Mutation Research - Reviews in Mutation Research | Year: 2010

Several proteins involved in DNA repair and DNA damage signaling have been shown to produce discrete foci in response to ionizing radiation. These foci are believed to co-localize to DSB and referred to as ionizing radiation-induced foci (IRIF) or DNA repair foci. Recent studies have revealed that some residual IRIF remain in cells for a relatively long time after irradiation, and have indicated a possible correlation between radiosensitivity of cells and residual IRIF. Remarkably, residual foci are significantly larger in size than the initial foci. Increase in the size of IRIF with time upon irradiation has been found in various cell types and has partially been correlated with dynamics and fusion of initial foci. Although it is admitted that the number of IRIF reflect that of DSB, several studies report a lack of correlation between kinetics for IRIF and DSB and a lack of co-localization between DSB repair proteins. These studies suggest that some proportion of residual IRIF that depend on cell type, dose, and post-irradiation time may represent alternations in chromatin structure after DSB have been repaired or misrepaired. While precise functions of residual foci are presently unknown, their possible link to remaining chromatin alternations, nuclear matrix, apoptosis, delayed repair and misrejoining of DSB, activity of several kinases, phosphatases, and checkpoint signaling has been suggested. Another intriguing possibility is that some of DNA repair foci may mark break-points at chromosomal aberrations (CA). While this possibility has not been confirmed substantially, the residual foci seem to be useful for biological dosimetry and estimation of individual radiosensitivity in radiotherapy of cancer. © 2010 Elsevier B.V. All rights reserved.

Barkhuus L.,University of Stockholm
Conference on Human Factors in Computing Systems - Proceedings | Year: 2012

Privacy is a widely studied concept in relation to social computing and sensor-based technologies; scores of research papers have investigated people's 'privacy preferences' and apparent reluctance to share personal data. In this paper we explore how Ubicomp and HCI studies have approached the notion of privacy, often as a quantifiable concept. Leaning on several theoretical frameworks, but in particular Nissenbaum's notion of contextual integrity, we question the viability of obtaining universal answers in terms of people's 'general' privacy practices and apply elements of Nissenbaum's theory to our own data in order to illustrate its relevance. We then suggest restructuring inquiries into information sharing in studies of state-of-the-art technologies and analyze contextually grounded issues using a different, more specific vocabulary. Finally, we provide the first building blocks to such vocabulary. Copyright 2012 ACM.

Milstead D.,University of Stockholm
Nuclear and Particle Physics Proceedings | Year: 2015

The ATLAS experiment at the Large Hadron Collider has produced a number of measurements of final state observables which are sensitive to soft processes mediated by the strong force. In this article, measurements of identified particle production (ϕ(1020)) are presented as are studies of the underlying event and double parton scattering. © 2015 Elsevier B.V.

Blomqvist J.,University of Stockholm
Addiction Research and Theory | Year: 2012

Respondents to a representative population survey were asked to rate four psychoactive substances (tobacco, alcohol, cannabis and 'hard' drugs) with regard to their severity to society and addictiveness, as well as the options for recovery, with and without treatment, from an addiction to the same substances. This article explores if and how these ratings differ with regard to respondents' socio-demographic characteristics, their own and close persons' substance use experiences, and, their attitudes towards people with substance use problems. Data were analysed using descriptive statistics and logistic or linear regressions. Although the main difference goes between respondents' perceptions of various substances and addictions, the results also point to some interesting differences with regard to respondents' experiences and characteristics. Thus for example, women and respondents with no personal substance use experiences, tend to play up the severity and addictiveness of most substances, and to play down the options for untreated recovery from an addiction, whereas current risk users tend to take an opposite view. Main interpretations are that there is a general tendency to exaggerate the hazards of and risks with habits that are perceived as unfamiliar and alien, that current risk users at the same time dwell on a 'false hope' of being able to quit, and that women are, for various reasons, more inclined than men to worry about their own substance use habits, as well as those in their close environment. Potential implications, for further research as well as for policy and prevention, are discussed. © 2012 Informa UK Ltd.

Large-scale phylogenies provide a valuable source to study background diversification rates and investigate if the rates have changed over time. Unfortunately most large-scale, dated phylogenies are sparsely sampled (fewer than 5% of the described species) and taxon sampling is not uniform. Instead, taxa are frequently sampled to obtain at least one representative per subgroup (e.g. family) and thus to maximize diversity (diversified sampling). So far, such complications have been ignored, potentially biasing the conclusions that have been reached. In this study I derive the likelihood of a birth-death process with non-constant (time-dependent) diversification rates and diversified taxon sampling. Using simulations I test if the true parameters and the sampling method can be recovered when the trees are small or medium sized (fewer than 200 taxa). The results show that the diversification rates can be inferred and the estimates are unbiased for large trees but are biased for small trees (fewer than 50 taxa). Furthermore, model selection by means of Akaike's Information Criterion favors the true model if the true rates differ sufficiently from alternative models (e.g. the birth-death model is recovered if the extinction rate is large and compared to a pure-birth model). Finally, I applied six different diversification rate models - ranging from a constant-rate pure birth process to a decreasing speciation rate birth-death process but excluding any rate shift models - on three large-scale empirical phylogenies (ants, mammals and snakes with respectively 149, 164 and 41 sampled species). All three phylogenies were constructed by diversified taxon sampling, as stated by the authors. However only the snake phylogeny supported diversified taxon sampling. Moreover, a parametric bootstrap test revealed that none of the tested models provided a good fit to the observed data. The model assumptions, such as homogeneous rates across species or no rate shifts, appear to be violated. © 2014 Sebastian Höhna.

Mood C.,University of Stockholm
Preventive Medicine | Year: 2013

Objective: To study the relations between lifestyle factors (smoking, drinking, exercise, vegetable consumption, social relations) and global self-rated health in the adult Swedish population. Method: The data come from the Swedish Level of Living Survey, a face-to-face panel study. The analysis follows the respondents with good health in 1991 (N = 4035) and uses multivariate logistic regression to assess the relations between lifestyle factors in 1991 and health in 2000 and 2010. Results: Baseline (1991) exercise, social support, smoking and vegetable consumption are associated with health in 2000 and/or 2010. 2000: Weekly exercise in 1991 increases the probability of good health by 6 percentage points [95% CI: 1-10] compared to no exercise, and smoking 10 or more cigarettes a day decreases the probability of good health by 5 percentage points [95% CI 1-8]. Lacking social support decreases the probability of good health by 17 percentage points (95% CI: 9-25). 2010: Smoking 10 or more cigarettes a day decreases the probability of good health by 10 percentage points [95% CI 5-15], and eating vegetables every day increases the probability of good health by 4 percentage points [95% CI 0.2-7]. Conclusions: Exercise, smoking, social support and vegetable consumption are related to self-rated health 2000 and/or 2010. © 2013 Elsevier Inc.

Leander L.,University of Stockholm
Child Abuse and Neglect | Year: 2010

Objective: The present study investigated 27 sexually abused children's reports about abuse given in the context of police interviews. All abuse cases had been verified (with, e.g., photographs or video films), proving that abuse had occurred. Method: The interviews with the children were analyzed regarding amount and type of information reported, and the frequency of denial and avoidance. Furthermore, children's reporting on different interview occasions was investigated. Results: Children reported significantly more neutral information from the abusive acts per se than sexual information. The children were also highly avoidant and, on several occasions, denied that (documented) sexual acts had occurred. Furthermore, the second and third interviews generated twice as many (new) sexual details as the first interview. The children also produced more denials and avoidances at the first interview compared to subsequent interviews. Conclusions: The present study indicates that sexually abused children may be highly resistant to reporting about the abuse in police interviews, and that two or three interviews may be needed to enable children to give complete and informative reports. It is of vital importance that professionals within the legal system be aware of this problem when conducting child interviews and when evaluating the reliability of child sexual abuse reports. © 2010 Elsevier Ltd.

Li J.-Q.,China Agricultural University | Andersson P.G.,University of Stockholm | Andersson P.G.,University of KwaZulu - Natal
Chemical Communications | Year: 2013

A bidentate iridium NHC-phosphine complex has been developed and applied to the N-monoalkylation of aromatic amines with a wide range of primary alcohols and to the N-heterocyclization of amino alcohols. This reaction resulted in high isolated product yields, even at room temperature and under solvent-free conditions. © The Royal Society of Chemistry 2013.

Svenaeus F.,University of Stockholm
Theoretical Medicine and Bioethics | Year: 2013

Heidegger's thoughts on modern technology have received much attention in many disciplines and fields, but, with a few exceptions, the influence has been sparse in biomedical ethics. The reason for this might be that Heidegger's position has been misinterpreted as being generally hostile towards modern science and technology, and the fact that Heidegger himself never subjected medical technologies to scrutiny but was concerned rather with industrial technology and information technology. In this paper, Heidegger's philosophy of modern technology is introduced and then brought to bear on medical technology. Its main relevance for biomedical ethics is found to be that the field needs to focus upon epistemological and ontological questions in the philosophy of medicine related to the structure and goal of medical practice. Heidegger's philosophy can help us to see how the scientific attitude in medicine must always be balanced by and integrated into a phenomenological way of understanding the life-world concerns of patients. The difference between the scientific and the phenomenological method in medicine is articulated by Heidegger as two different ways of studying the human body: as biological organism and as lived body. Medicine needs to acknowledge the priority of the lived body in addressing health as a way of being-in-the-world and not as the absence of disease only. A critical development of Heidegger's position can provide us with a criterion for distinguishing the uses of medical technologies that are compatible with such an endeavor from the technological projects that are not. © 2012 Springer Science+Business Media Dordrecht.

Koenigk T.,Swedish Meteorological and Hydrological Institute | Brodeau L.,University of Stockholm
Climate Dynamics | Year: 2014

The ocean heat transport into the Arctic and the heat budget of the Barents Sea are analyzed in an ensemble of historical and future climate simulations performed with the global coupled climate model EC-Earth. The zonally integrated northward heat flux in the ocean at 70°N is strongly enhanced and compensates for a reduction of its atmospheric counterpart in the twenty first century. Although an increase in the northward heat transport occurs through all of Fram Strait, Canadian Archipelago, Bering Strait and Barents Sea Opening, it is the latter which dominates the increase in ocean heat transport into the Arctic. Increased temperature of the northward transported Atlantic water masses are the main reason for the enhancement of the ocean heat transport. The natural variability in the heat transport into the Barents Sea is caused to the same extent by variations in temperature and volume transport. Large ocean heat transports lead to reduced ice and higher atmospheric temperature in the Barents Sea area and are related to the positive phase of the North Atlantic Oscillation. The net ocean heat transport into the Barents Sea grows until about year 2050. Thereafter, both heat and volume fluxes out of the Barents Sea through the section between Franz Josef Land and Novaya Zemlya are strongly enhanced and compensate for all further increase in the inflow through the Barents Sea Opening. Most of the heat transported by the ocean into the Barents Sea is passed to the atmosphere and contributes to warming of the atmosphere and Arctic temperature amplification. Latent and sensible heat fluxes are enhanced. Net surface long-wave and solar radiation are enhanced upward and downward, respectively and are almost compensating each other. We find that the changes in the surface heat fluxes are mainly caused by the vanishing sea ice in the twenty first century. The increasing ocean heat transport leads to enhanced bottom ice melt and to an extension of the area with bottom ice melt further northward. However, no indication for a substantial impact of the increased heat transport on ice melt in the Central Arctic is found. Most of the heat that is not passed to the atmosphere in the Barents Sea is stored in the Arctic intermediate layer of Atlantic water, which is increasingly pronounced in the twenty first century. © 2013 The Author(s).

Norholm M.H.H.,University of Stockholm
BMC Biotechnology | Year: 2010

Background: The combined use of restriction enzymes with PCR has revolutionized molecular cloning, but is inherently restricted by the content of the manipulated DNA sequences. Uracil-excision based cloning is ligase and sequence independent and allows seamless fusion of multiple DNA sequences in simple one-tube reactions, with higher accuracy than overlapping PCR.Results: Here, the addition of a highly efficient DNA polymerase and a low-background-, large-insertion- compatible site-directed mutagenesis protocol is described, largely expanding the versatility of uracil-excision DNA engineering.Conclusions: The different uracil-excision based molecular tools that have been developed in an open-source fashion, constitute a comprehensive, yet simple and inexpensive toolkit for any need in molecular cloning. © 2010 Nørholm; licensee BioMed Central Ltd.

Toivanen S.,University of Stockholm
American Journal of Industrial Medicine | Year: 2011

Background: This study explored the interplay between work stress and socioeconomic position and investigated if the interaction of work stress and low socioeconomic position is associated with poorer health. Methods: A representative sample of the Swedish working population, including 2,613 employees (48.7% women) aged 19-64 years, was analyzed. The health outcomes were poor self-rated health, psychological distress, and musculoskeletal pain. Work stress was operationalized as job strain and effort-reward imbalance, and socioeconomic position as occupational class. Interaction analysis was based on departure from additivity as criterion, and a synergy index (SI) was applied, using odds ratios (ORs) from logistic regressions for women and men. Results/Conclusions: In fully adjusted models, work stress, and in a lesser extent also socioeconomic position, was associated with higher odds for the three health complaints. The prevalence of poorer health was highest among those individuals jointly exposed to high work stress and low occupational class, with ORs ranging from 1.94 to 6.77 (95%CI 1.01-18.65) for poor self-rated health, 2.42-8.44 (95%CI 1.28-27.06) for psychological distress and 1.93-3.93 (95%CI 1.11-6.78) for musculoskeletal pain. The joint influence of work stress and low socioeconomic position on health was additive rather than multiplicative. © 2011 Wiley-Liss, Inc.

Helmens K.F.,University of Stockholm
Quaternary Science Reviews | Year: 2014

Current multi-proxy studies on a long sediment sequence preserved at Sokli (N Finland), i.e. in the central area of Fennoscandian glaciations, are drastically changing classic ideas of glaciations, vegetation and climate in northern Europe during the Late Pleistocene. The sediments in the Sokli basin have escaped major glacial erosion due to non-typical bedrock conditions. In this review, the Sokli record is compared in great detail with other long proxy records from central, temperate and northern, boreal Europe. These comprise the classic records of La Grande Pile (E France) and Oerel (N Germany) and more recently obtained records from Horoszki Duże (E Poland) and Lake Yamozero (NW Russia). The focus of the review is on pollen, lithology and macrofossil- and insect-based temperature inferences. The long records are further compared with recent proxy data from nearby terrestrial sites as well as with the rapidly accumulating high-resolution proxy data from the ocean realm. The comparison allows a re-examination of the environmental history and climate evolution of the Last Interglacial-Glacial (LI-G) cycle (MIS 5-2). It shows that environmental and climate conditions during MIS 5 (ca130-70kaBP) were distinctly different from those during MIS 4-2 (ca70-15kaBP). MIS 5 is characterized by three long forested intervals (broadly corresponding to MIS 5e, 5c, 5a), both in temperate and northern boreal Europe. These mild periods were interrupted by two short, relatively cold and dry intervals (MIS 5d and 5b) with mountain-centered glaciation in Fennoscandia. Millennial scale climate events were superimposed upon these longer lasting climate fluctuations. The time interval encompassing MIS 4-2 shows open vegetation. It is characterized by two glacial maxima (MIS 4 and 2) with sub-continental scale glaciation over northern Europe and dry conditions in strongly continental eastern European settings. High amplitude climate oscillations of millennial duration characterized the climate variability of MIS 3. Mild climate conditions in early MIS 3 caused large-scale deglaciation of the Fennoscandian Ice Sheet, and ice-free conditions with Betula-dominated vegetation (including tree birch) persisted over large parts of Fennoscandia, possibly interrupted by glaciation, during major part of MIS 3 till ca35kaBP. Overall, MIS 5 was mostly mild with warmest or peak interglacial conditions at the very start during MIS 5e. MIS 4-2 was mostly cold with most extreme or peak glacial conditions in the closing phase during MIS 2. This points to a subdivision of the last climate cycle into an early, overall mild interglacial half and a late, overall cold glacial half, each with duration of ca50ka. This review also shows that the climate variability in central and northern Europe during the LI-G cycle was mostly in degrees of continentality with major shifts in winter temperature and precipitation values; summer temperatures, on the other hand, remained largely unchanged. It points to the waxing and waning of sea-ice over the North Atlantic Ocean as a possible characteristic feature of the Late Pleistocene. The present compilation, based on long terrestrial sequences, high-resolution multi-proxy data from the oceans, and quantified paleo-climate data, strongly favors a definition of entire Marine Oxygen Isotope Stage 5 as the Last Interglacial similar as in the original marine stratigraphy and the stratigraphy at La Grande Pile in France. The proxy-based climate data places the start of the Last Glacial at the base of MIS 4 and the northwest European Pleniglacial. It shows that the division between the Eemian (MIS 5e) and the Early Weichselian (MIS 5d-a) is not useful, as not relevant from a climate point of view. © 2013 Elsevier Ltd.

Eriksson O.,University of Stockholm
Journal of Vegetation Science | Year: 2014

Question: Eco-evolutionary dynamics is a concept encapsulating a feedback between ecology and evolution, acting on short ecological time-scales. Recent studies suggest that such dynamics have been generally over-looked. The objective of this paper is to examine how eco-evolutionary dynamics may contribute to vegetation science. Location: Global. Methods: In this paper I discuss eco-evolutionary dynamics in the context of vegetation science, with a focus on effects derived from human-mediated niche construction,manifested as new habitats, non-native species, and changing connectivity and spatial configuration of habitats. Results and Conclusions: I suggest that eco-evolutionary dynamics have the potential to influence plant community composition and assembly, and thus that eco-evolutionary dynamics should become focus of studies in vegetation science. © 2014 International Association for Vegetation Science.

Lidmar-Bergstrom K.,University of Stockholm | Bonow J.M.,Sodertorn University College | Japsen P.,Geological Survey of Denmark
Global and Planetary Change | Year: 2013

Stratigraphic Landscape Analysis (SLA) is based on a) the relationship between peneplains (low-relief denudation surfaces) in basement and their cover rocks of different age, b) the crosscutting relationships between such re-exposed peneplains and never covered (epigene) peneplains, and c) the occurrence of valleys incised below peneplains. Previous studies based on detailed SLA of the South Swedish Dome (SSD) have identified two major re-exposed peneplains, the flat sub-Cambrian peneplain and the sub-Jurassic/Cretaceous peneplain with undulating hilly relief. Both surfaces developed close to former sea levels, were subsequently transgressed, and buried below sedimentary covers. The preservation of these peneplains documents that uplift of the land surface was followed by subsidence. Crosscutting relationships between these re-exposed and tilted peneplains and a third peneplain, an epigene and horizontal plain with residual hills, demonstrate that the latter is younger and thus of post-Cretaceous age. Three topographic highs characterize Scandinavia, the Northern Scandes (NS), the Southern Scandes (SS), and the low SSD. We show that the three relief types of the SSD can be identified across Scandinavia and that they demonstrate phases of uplift/denudation and subsidence/burial of Scandinavia during the Phanerozoic. In particular, we show that the epigene peneplains of the NS, the SS and the SSD are Cenozoic erosion surfaces and this also leads us to identify three major Cenozoic morphotectonic units. A result of our studies is that the paradigm of continuous uplift of steady state landscapes cannot be assumed as a universal model of landform evolution. © 2012 Elsevier B.V..

Luirink J.,VU University Amsterdam | Yu Z.,VU University Amsterdam | Wagner S.,University of Tubingen | De Gier J.-W.,University of Stockholm
Biochimica et Biophysica Acta - Bioenergetics | Year: 2012

The inner membrane proteome of the model organism Escherichia coli is composed of inner membrane proteins, lipoproteins and peripherally attached soluble proteins. Our knowledge of the biogenesis of inner membrane proteins is rapidly increasing. This is in particular true for the early steps of biogenesis - protein targeting to and insertion into the membrane. However, our knowledge of inner membrane protein folding and quality control is still fragmentary. Furthering our knowledge in these areas will bring us closer to understand the biogenesis of individual inner membrane proteins in the context of the biogenesis of the inner membrane proteome of Escherichia coli as a whole. This article is part of a Special Issue entitled: Biogenesis/Assembly of Respiratory Enzyme Complexes. © 2011 Elsevier B.V.

Enormous amounts of 13C-depleted carbon rapidly entered the exogenic carbon cycle during the onset of the Paleocene-Eocene thermal maximum (PETM), as attested to by a prominent negative carbon isotope (δ 13C) excursion and deep-sea carbonate dissolution. A widely cited explanation for this carbon input has been thermal dissociation of gas hydrate on continental slopes, followed by release of CH 4 from the seafloor and its subsequent oxidation to CO 2 in the ocean or atmosphere. Increasingly, papers have argued against this mechanism, but without fully considering existing ideas and available data. Moreover, other explanations have been presented as plausible alternatives, even though they conflict with geological observations, they raise major conceptual problems, or both. Methane release from gas hydrates remains a congruous explanation for the δ 13C excursion across the PETM, although it requires an unconventional framework for global carbon and sulfur cycling, and it lacks proof. These issues are addressed here in the hope that they will prompt appropriate discussions regarding the extraordinary carbon injection at the start of the PETM and during other events in Earth's history. © Author(s) 2011.

De Wijn A.S.,University of Stockholm | Fasolino A.,Radboud University Nijmegen | Filippov A.E.,NASU Institute of Physics | Urbakh M.,Tel Aviv University
Physical Review Letters | Year: 2014

We propose a theoretical model of friction under electrochemical conditions focusing on the interaction of a force microscope tip with adsorbed polar molecules whose orientation depends on the applied electric field. We demonstrate that the dependence of friction force on the electric field is determined by the interplay of two channels of energy dissipation: (i) the rotation of dipoles and (ii) slips of the tip over potential barriers. We suggest a promising strategy to achieve a strong dependence of nanoscopic friction on the external field based on the competition between long-range electrostatic interactions and short-range chemical interactions between tip and adsorbed polar molecules. © 2014 American Physical Society.

This essay explores the gendered lifestyle of early twentieth-century physics and chemistry and shows how that way of life was produced through linking science and home. In 1905, the Swedish physical chemist Svante Arrhenius married Maja Johansson and established a scientific household at the Nobel Institute for Physical Chemistry in Stockholm. He created a productive context for research in which ideas about marriage and family were pivotal. He also socialized in similar scientific sites abroad. This essay displays how scholars in the international community circulated the gendered lifestyle through frequent travel and by reproducing gendered behavior. Everywhere, husbands and wives were expected to perform distinct duties. Shared performances created loyalties across national divides. The essay thus situates the physical sciences at the turn of the twentieth century in a bourgeois gender ideology. Moreover, it argues that the gendered lifestyle was not external to knowledge making but, rather, foundational to laboratory life. A legitimate and culturally intelligible lifestyle produced the trust and support needed for collaboration. In addition, it enabled access to prestigious facilities for Svante Arrhenius, ultimately securing his position in international physical chemistry. © 2014 by The History of Science Society. All rights reserved.

Maler L.,University of Stockholm
Methods in molecular biology (Clifton, N.J.) | Year: 2011

CPPs are generally short cationic peptides that have the capability to interact directly with membranes. Most CPPs attain a three-dimensional structure when interacting with bilayers, while they are more or less unstructured in aqueous solution. To understand the relationship between structure and the effect that CPPs have on membranes, it is of great importance to investigate CPPs with atomic resolution in a suitable membrane model. Nuclear magnetic resonance (NMR) is an excellent technique both for studying solution structures of peptides as well as for investigating their location within a model bilayer. This chapter outlines protocols for producing model membrane systems for NMR investigations as well as the basic NMR tools for determining the three-dimensional structure of CPPs and for investigating the details in lipid-peptide interactions, i.e., the localization of the CPP in the bilayer.

Graslund A.,University of Stockholm
Methods in molecular biology (Clifton, N.J.) | Year: 2011

The chapter deals with some biophysical methods used for investigating CPP-induced changes in membrane properties by spectroscopy methods such as fluorescence or NMR and methods used for probing CPP-induced leakage in membranes. Some useful model systems for biomembranes are described. These include large unilamellar phospholipid vesicles (LUVs) of well-defined size (diameter typically 100 nm). A protocol for the preparation of such vesicles is included. The leakage studies make use of LUVs with entrapped dye molecules. The NMR studies make use of mixed micelles (bicelles) as a membrane mimetic system, which can be oriented in the magnetic field of the spectrometer.

Pawlowski K.,University of Stockholm | Demchenko K.N.,RAS Komarov Botanical Institute
Protoplasma | Year: 2012

Filamentous aerobic soil actinobacteria of the genus Frankia can induce the formation of nitrogen-fixing nodules on the roots of a diverse group of plants from eight dicotyledonous families, collectively called actinorhizal plants. Within nodules, Frankia can fix nitrogen while being hosted inside plant cells. Like in legume/rhizobia symbioses, bacteria can enter the plant root either intracellularly through an infection thread formed in a curled root hair, or intercellularly without root hair involvement, and the entry mechanism is determined by the host plant species. Nodule primordium formation is induced in the root pericycle as for lateral root primordia. Mature actinorhizal nodules are coralloid structures consisting of multiple lobes, each of which represents a modified lateral root without a root cap, a superficial periderm and with infected cells in the expanded cortex. In this review, an overview of nodule induction mechanisms and nodule structure is presented including comparisons with the corresponding mechanisms in legume symbioses. © 2012 Springer-Verlag.

Bergman L.R.,University of Stockholm
International Journal of Developmental Sciences | Year: 2012

Developmental science (DS) is defined somewhat differently by different researchers. In the present essay DS is defined as (1) it concerns understanding individual development, partly in contrast to group development, (2) DS is cross-disciplinary, and (3) the individual is regarded as a 'functioning whole', engaged in a developmental process in context, characterized by interactions. Empirical research carried out within a DS framework must pay attention to many issues such as: (1) The translation of a specific DS theory into informative hypotheses. (2) The integration of DS findings with the research literature. (3) Making the findings interpretable as addressing individual development. Finally, it was pointed out that to maximally advance DS research a shared general theoretical framework and set of central concepts are necessary. © 2012 - IOS Press and the authors. All rights reserved.

Laikre L.,University of Stockholm
Conservation Genetics | Year: 2010

The importance of genetic variation for maintaining biological diversity and evolutionary processes has been recognized by researchers for decades. This realization has prompted agreements by world leaders to conserve genetic diversity, and this is an explicit goal of the Convention on Biological Diversity (CBD). Nevertheless, very limited action has been taken to protect genetic diversity on a global scale. International conservation efforts to halt biodiversity loss focus on habitats and species, whereas little or no attention is paid to gene level variation. By this year, 2010, world leaders have agreed that a significant reduction of the rate of biodiversity loss should have been achieved. However, gene level diversity is still not monitored, indicators that can help identify threats to genetic variation are missing, and there is no strategy for how genetic aspects can be included in biodiversity targets beyond 2010. Important findings and conclusions from decades of conservation genetic research are not translated into concrete conservation action in the arena of international policy development. There is an urgent need for conservation geneticists worldwide to become involved in policy and practical conservation work beyond the universities and research institutions. © 2010 Springer Science+Business Media B.V.

Nassel D.R.,University of Stockholm
Canadian Journal of Zoology | Year: 2012

Insulin-like peptide signaling regulates development, growth, reproduction, metabolism, stress resistance, and life span in a wide spectrum of animals. Not only the peptides, but also their tyrosine kinase receptors and the downstream signaling pathways are conserved over evolution. This review summarizes roles of insulin-like peptides (DILPs) in physiology and behavior of Drosophila melanogaster Meigen, 1830. Seven DILPs (DILP1-7) and one receptor (dInR) have been identified in Drosophila. These DILPs display cell and stage specific expression patterns. In the adult, DILP2, 3, and 5 are expressed in insulin-producing cells (IPCs) among the median neurosecretory cells of the brain, DILP7 in 20 neurons of the abdominal ganglion, and DILP6 in the fat body. The DILPs of the IPCs regulate starvation resistance, responses to oxidative and temperature stress, and carbohydrate and lipid metabolism. Furthermore, the IPCs seem to regulate feeding, locomotor activity, sleep and ethanol sensitivity, but the mechanisms are not elucidated. Insulin also alters the sensitivity in the olfactory system that affects food search behavior, and regulates peptidergic neurons that control aspects of feeding behavior. Finally, the control of insulin production and release by humoral and neuronal factors is discussed. This includes a fat body derived factor and the neurotransmitters GABA, serotonin, octopamine, and two neuropeptides.

Strauss J.,University of Stockholm
Frontiers in bioscience : a journal and virtual library | Year: 2010

Circadian rhythms are known for locomotory and reproductive behaviours, and the functioning of sensory organs, nervous structures, metabolism and developmental processes. The mechanisms and cellular bases of control are mainly inferred from circadian phenomenologies, ablation experiments and pharmacological approaches. Cellular systems for regulation summarised here comprise the retina, the eyestalk neuroendocrine X-organ-sinus gland system, several neuropeptides such as red pigment concentrating, hyperglycaemic and pigment-dispersing hormones, and factors such as serotonin and melatonin. No master clock has been identified, but a model of distributed clockwork involves oscillators such as the retinular cells, neurosecretory systems in the optic lobes, putative brain pacemakers, and the caudal photoreceptor. Extraretinal brain photoreceptors mediate entrainment. Comparative analyses of clock neurons and proteins known from insects may allow the identification of candidate clock neurons in crustaceans as putative homologues in the two taxa. Evidence for the existence of "insect-like" intracellular clock proteins and (light sensitive) transcription factors is scarce, but clock-, period-, and cryptochrome-gene products have been localised in the CNS and other organs rendering further investigations into crustacean clockwork very promising.

Visa N.,University of Stockholm
Cold Spring Harbor perspectives in biology | Year: 2010

Actin participates in several essential processes in the cell nucleus. Even though the presence of actin in the nucleus was proposed more than 30 years ago, nuclear processes that require actin have been only recently identified. Actin is part of chromatin remodeling complexes; it is associated with the transcription machineries; it becomes incorporated into newly synthesized ribonucleoproteins; and it influences long-range chromatin organization. As in the cytoplasm, nuclear actin works in conjunction with different types of actin-binding proteins that regulate actin function and bridge interactions between actin and other nuclear components.

Nassel D.R.,University of Stockholm | Wegener C.,University of Marburg
Peptides | Year: 2011

Neuropeptides referred to as neuropeptide F (NPF) and short neuropeptide F (sNPF) have been identified in numerous invertebrate species. Sequence information has expanded tremendously due to recent genome sequencing and EST projects. Analysis of sequences of the peptides and prepropeptides strongly suggest that NPFs and sNPFs are not closely related. However, the NPFs are likely to be ancestrally related to the vertebrate family of neuropeptide Y (NPY) peptides. Peptide diversification may have been accomplished by different mechanisms in NPFs and sNPFs; in the former by gene duplications followed by diversification and in the sNPFs by internal duplications resulting in paracopies of peptides. We discuss the distribution and functions of NPFs and their receptors in several model invertebrates. Signaling with sNPF, however, has been investigated mainly in insects, especially in Drosophila. Both in invertebrates and in mammals NPF/NPY play roles in feeding, metabolism, reproduction and stress responses. Several other NPF functions have been studied in Drosophila that may be shared with mammals. In Drosophila sNPFs are widely distributed in numerous neurons of the CNS and some gut endocrines and their functions may be truly pleiotropic. Peptide distribution and experiments suggest roles of sNPF in feeding and growth, stress responses, modulation of locomotion and olfactory inputs, hormone release, as well as learning and memory. Available data indicate that NPF and sNPF signaling systems are distinct and not likely to play redundant roles. © 2011 Elsevier Inc. All rights reserved.

Edman J.,University of Stockholm
International Journal of Drug Policy | Year: 2016

Background: This article examines developments in the Swedish drug treatment services in 1982-2000 and explores the ways in which political initiatives and the state administration's management have contributed to the major privatisations of institutional drug treatment during this period. Methods: The empirical basis for the textual analysis lies in official reports, parliamentary material and archived records from the Stockholm County Administrative Board's management of treatment facilities. Results: The major privatisations of drug treatment services in the 1980s were both unintentional and unwanted and mainly arose from a lack of bureaucratic control and ideological anchorage. The privatisations were, however, reinforced by ideologically driven NPM-oriented political initiatives in the 1990s. Conclusion: The market-oriented treatment services have failed to fulfil the needs for diversity and availability within a publicly financed sector, which deals with unevenly informed and often socio-economically weak citizens. New management models in this field must ensure that ideological considerations are taken into account to meet politically decided goals and means. © 2016 Elsevier B.V.

Branden P.,University of Stockholm | Claesson A.,University of Strathclyde
Electronic Journal of Combinatorics | Year: 2011

Any permutation statistic f:G → ℂ may be represented uniquely as a, possibly infinite, linear combination of (classical) permutation patterns: f = Στλf(τ)τ. To provide explicit expansions for certain statistics, we introduce a new type of permu- tation patterns that we call mesh patterns. Intuitively, an occurrence of the mesh pattern p = (π, R) is an occurrence of the permutation pattern π with additional restrictions specified by R on the relative position of the entries of the occurrence. We show that, for any mesh pattern p = (π, R), we have λp(τ) = (-1){pipe}τ{pipe}-{pipe}π{pipe}p*(τ) where p* = (π,Rc) is the mesh pattern with the same underlying permutation as p but with complementary restrictions. We use this result to expand some well known permutation statistics, such as the number of left-to-right maxima, descents, excedances, fixed points, strong fixed points, and the major index. We also show that alternating permutations, André permutations of the first kind and simsun per- mutations occur naturally as permutations avoiding certain mesh patterns. Finally, we provide new natural Mahonian statistics.

Andersson C.,University of Stockholm | Andersson C.,Swedish Meteorological and Hydrological Institute | Engardt M.,Swedish Meteorological and Hydrological Institute
Journal of Geophysical Research: Atmospheres | Year: 2010

[1] Projections of future surface ozone over Europe conducted utilizing chemistry transport models (CTMs) coupled to climate models differ greatly, even in sign. CTM sensitivity studies were conducted in order to investigate the importance of changes in natural isoprene emissions and dry deposition to vegetation, both coupled to meteorology. This knowledge can be used to improve surface ozone projections. Our simulations suggest climate change over Europe would cause changes in surface ozone between -4.0 to +13 ppb(v) on average (April-September) and -3.5 to +25 ppb(v) on average (April-September) daily maximum from 1961-1990 to 2071-2100. The change is positive in the southwest and negative in the north. The isoprene emissions increased by a factor of about 1.8 from 1961-1990 to 2071-2100. A rescaling of isoprene emissions shows that the large increase in isoprene emission is of importance (0-30% of the change in surface ozone) in central, southern, and western Europe. The use of a formulation for ozone dry deposition to vegetation, dependent on meteorology, and changes in snow cover, affecting the dry deposition, are more important processes. The changes in dry deposition to vegetation (not including changes in aerodynamic resistance) explain up to 80% of the surface ozone change in Spain. Therefore it is vital to include meteorological dependence for dry deposition of ozone to vegetation in surface ozone projections. Isoprene emissions are of less importance, but they are nonnegligible and should definitely be emitted online in climate ozone projection studies. Copyright © 2010 by the American Geophysical Union.

Sneiders E.,University of Stockholm
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

Answering email by standard answers is a common practice at contact centers. Our research assists this process by creating reply messages that contain one or several standard answers. Our standard answers are linked to representative text patterns that match incoming messages. The system works in three languages. The performance was evaluated on two email sets; the main advantage of our email answering technique is good correctness of the delivered replies. © 2010 Springer-Verlag Berlin Heidelberg.

Szabo K.J.,University of Stockholm
Topics in Organometallic Chemistry | Year: 2013

Application of pincer complexes in catalytic applications is a rapidly expanding field in organic synthesis. This chapter is mainly focused on selective formation of carbon-carbon, carbon-nitrogen, and carbon-metal (C-B, C-Si, and S-Sn) bonds, as well as transfer hydrogenation reactions. The described pincer-complex catalyzed processes are more efficient and more selective than the corresponding transformations catalyzed by metal salts and added ligands. Some of the described pincer-complex catalyzed reactions are not amenable by traditional metal catalysts at all. It has been demonstrated that the superiority of pincer-complex catalysts over the traditional ones is based on the high stability and well-defined structure and stoichiometry of these species. These properties of pincer complexes allow a rational design of active and highly selective catalysts. © 2013 Springer-Verlag Berlin Heidelberg.

Hugelius G.,University of Stockholm
Global Biogeochemical Cycles | Year: 2012

Studies of periglacial regions confirm their importance in the global carbon (C) cycle, but estimates of ecosystem C storage or green-house gas fluxes from these remote areas are generally poorly constrained and quantitative estimates of upscaling uncertainties are lacking. In this study, a regional database describing soil organic carbon (SOC) storage in periglacial terrain (European Russian Arctic) was used to evaluate spatial upscaling from point measurements using thematic maps. The selection of classes for upscaling and the need for replication in soil sampling were statistically evaluated. Upscaling using a land cover classification and a soil map estimated SOC storage to 48.5 and 47.0 kg C m-2, respectively with 95% confidence intervals (CI) within 8%. When corrected for spatial errors in the LCC upscaling proxy, SOC was estimated to 46.5 kg C m-2 with a 95% CI reflecting propagated variance from both natural variability and spatial errors of 11%. Artificially decreasing the size of the database used for upscaling showed that relatively stable results could be achieved with lower replication in some upscaling classes. Decreased spatial resolution for upscaling from 30 m to 1 km had little impact on SOC estimates in this region, but classification accuracy was dramatically reduced and land cover classes show different, sometimes nonlinear, responses to scale. The methods and recommendations presented here can provide guidelines for any future study where point observations of a variable are upscaled using remotely sensed thematic maps or classifications and potential applications for circum-arctic studies are discussed. For future upscaling studies at large geographic scales, a priori determination of sample sizes and tests to insure unimodal and statistically independent samples are recommended. If these prerequisites are not fulfilled, classes may be merged or subdivided prior to upscaling. Copyright 2012 by the American Geophysical Union.

Brown I.A.,University of Stockholm
International Journal of Remote Sensing | Year: 2010

The conflict in Darfur, Western Sudan, is frequently represented in the media as a dispute over access to resources by competing communities. Environmental degra- dation is often cited as either a causal or a contributory factor to the outbreak of the conflict and its prolongation. In this paper, Normalized Difference Vegetation Index (NDVI) data are used as a measure of 'eco-scarcity' to assess the notion that the outbreak of conflict was the result of competition for resources between communities. It is shown that there is no evidence in the vegetation mapping for a worsening of the ecological situation in Western and Northern Darfur states around the outbreak of the conflict. On the contrary, the years prior to the outbreak of the conflict experienced better than average vegetation growth in the context of the past 25 years. © 2010 Taylor & Francis.

Nycander J.,University of Stockholm
Tellus, Series A: Dynamic Meteorology and Oceanography | Year: 2010

An upper bound is derived for the total dissipation rate in an ocean forced exclusively by surface fluxes of heat and freshwater, assuming a non-linear equation of state. This generalizes the upper bound found by Paparella and Young, which is valid for a flow forced by an imposed temperature distribution at the surface and a linear equation of state. Like this previous result, the present one shows that the dissipation rate vanishes in the limit of vanishing molecular diffusivity of temperature and salinity, if the range of temperatures and salinities occurring in the fluid is regarded as given. A numerical evaluation for realistic ocean parameters shows that the upper bound is two orders of magnitude smaller than present estimates of the energy transformation involved in the deep ocean circulation. This supports the conclusion that mechanical forcing by winds and tides is necessary to sustain the deep ocean circulation. © 2009 The Author Journal compilation © 2010 Blackwell Munksgaard.

Carlsson C.,University of Stockholm
Criminology | Year: 2013

In life-course criminology, when gender has been the focus of study, it has predominantly been treated as a variable. Studies that explore the gendered nature of criminal careers through the lived experiences of offenders are rare, even though these studies can make important contributions to our understanding of crime and the life course. Analyzing qualitative data, this article uses life-history narratives of a small sample of male juvenile delinquents (N = 25), born in 1969-1974, to explore the possible link among masculinities, persistence, and desistance from crime. The findings of the study suggest that processes of persistence and desistance are imbued with age-specific norms of what it means to "be a man" and successfully do masculinity in different stages of life. Analyzing these gender-specific practices gives a deepened understanding of processes that underlie the offenders' lives as they go through stages of continuity and change in crime. The findings of the study further suggest a complex intersection between gendered biographies and gendered structures, with fruitful contributions to life-course criminology. The implications of these findings are discussed. © 2013 American Society of Criminology.

Goldner A.,Purdue University | Huber M.,Purdue University | Caballero R.,University of Stockholm
Climate of the Past | Year: 2013

In this study, we compare the simulated climatic impact of adding an Antarctic ice sheet (AIS) to the "greenhouse world" of the Eocene and removing the AIS from the modern world. The modern global mean surface temperature anomaly (ΔT) induced by Antarctic Glaciation depends on the background CO2 levels and ranges from -1.22 to -0.18 K. The Eocene ΔT is nearly constant at ∼-0.25 K. We calculate an climate sensitivity parameter S[Antarctica] which we define as ΔT divided by the change in effective radiative forcing (ΔQAntarctica) which includes some fast feedbacks imposed by prescribing the glacial properties of Antarctica.

The main difference between the modern and Eocene responses is that a negative cloud feedback warms much of the Earth's surface as a large AIS is introduced in the Eocene, whereas this cloud feedback is weakly positive and acts in combination with positive sea-ice feedbacks to enhance cooling introduced by adding an ice sheet in the modern. Because of the importance of cloud feedbacks in determining the final temperature sensitivity of the AIS, our results are likely to be model dependent. Nevertheless, these model results suggest that the effective radiative forcing and feedbacks induced by the AIS did not significantly decrease global mean surface temperature across the Eocene-Oligocene transition (EOT -34.1 to 33.6 Ma) and that other factors like declining atmospheric CO2 are more important for cooling across the EOT. The results illustrate that the efficacy of AIS forcing in the Eocene is not necessarily close to one and is likely to be model and state dependent. This implies that using EOT paleoclimate proxy data by itself to estimate climate sensitivity for future climate prediction requires climate models and consequently these estimates will have large uncertainty, largely due to uncertainties in modelling low clouds. © Author(s) 2013.

Christiansen B.,Danish Meteorological Institute | Ljungqvist F.C.,University of Stockholm
Climate of the Past | Year: 2012

We present two new multi-proxy reconstructions of the extra-tropical Northern Hemisphere (30-90°N) mean temperature: a two-millennia long reconstruction reaching back to 1 AD and a 500-yr long reconstruction reaching back to 1500 AD. The reconstructions are based on compilations of 32 and 91 proxies, respectively, of which only little more than half pass a screening procedure and are included in the actual reconstructions. The proxies are of different types and of different resolutions (annual, annual-to-decadal, and decadal) but all have previously been shown to relate to local or regional temperature. We use a reconstruction method, LOCal (LOC), that recently has been shown to confidently reproduce low-frequency variability. Confidence intervals are obtained by an ensemble pseudo-proxy method that both estimates the variance and the bias of the reconstructions. The two-millennia long reconstruction shows a well defined Medieval Warm Period, with a peak warming ca. 950-1050 AD reaching 0.6 °C relative to the reference period 1880-1960 AD. The 500-yr long reconstruction confirms previous results obtained with the LOC method applied to a smaller proxy compilation; in particular it shows the Little Ice Age cumulating in 1580-1720 AD with a temperature minimum of g -1.0 °C below the reference period. The reconstructed local temperatures, the magnitude of which are subject to wide confidence intervals, show a rather geographically homogeneous Little Ice Age, while more geographical inhomogeneities are found for the Medieval Warm Period. Reconstructions based on different subsets of proxies show only small differences, suggesting that LOC reconstructs 50-yr smoothed extra-tropical NH mean temperatures well and that low-frequency noise in the proxies is a relatively small problem. © Author(s) 2012. CC Attribution 3.0 License.

Barker V.,University of Stockholm
Theoretical Criminology | Year: 2013

Nordic penal regimes are Janus-faced: one side relatively mild and benign; the other intrusive, disciplining and oppressive. This paradox has not been fully grasped or explained by the Nordic Exceptionalism thesis which overstates the degree to which Nordic penal order is based on humaneness and social solidarity, an antidote to mass incarceration. This essay examines the split in the foundation of the Swedish welfare state: it simultaneously promotes individual well-being in the social sphere but enables intrusive deprivations of liberty and in some cases, violates the principles of human rights. The backbone of the welfare state, Folkhemmet, the People's Home, is at once demos, democratic and egalitarian and ethnos, a people by blood, exclusionary and essentialist. The lack of individual rights and an ethno-cultural conception of citizenship make certain categories of people such as criminal offenders, criminal aliens, drug offenders and perceived 'others', particularly foreign nationals, vulnerable to deprivation and exclusion. © The Author(s) 2012.

Holm N.G.,University of Stockholm
Geobiology | Year: 2012

Magnesium plays a special role in biochemistry because of its ability to coordinate six oxygen atoms efficiently in its first coordination shell. Such oxygen atoms may be part of one or two charged oxyanions, which means that Mg 2+ can, for instance, tie together two different phosphate groups that are located at distance from each other in a macromolecule, and in this way be responsible for the folding of molecules like RNA. This property of Mg 2+ also helps the stabilization of diphosphate and triphosphate groups of nucleotides, as well as promoting the condensation of orthophosphate to oligophosphates, like pyrophosphate and trimetaphosphate. Borates, on the other hand, are known to promote the formation of nucleobases and carbohydrates, ribose in particular, which is yet another constituent of nucleotides. The oldest borate minerals that we find on Earth today are magnesium borates. Dissolved borate stabilizes pentose sugars by forming complexes with cis-hydroxyl groups. In the furanose form of ribose, the preferential binding occurs to the 2 and 3 carbon, leaving the 5 carbon free for phosphorylation. The central role of Mg 2+ in the function of ribozymes and its 'archaic' position in ribosomes, and the fact that magnesium generally has coordination properties different from other cations, suggests that the inorganic chemistry of magnesium had a key position in the first chemical processes leading to the origin and early evolution of life. © 2012 Blackwell Publishing Ltd.

Brandenburg A.,NORDITA | Brandenburg A.,University of Stockholm | Nordlund A.,Niels Bohr Institute
Reports on Progress in Physics | Year: 2011

The role of turbulence in various astrophysical settings is reviewed. Among the differences to laboratory and atmospheric turbulence we highlight the ubiquitous presence of magnetic fields that are generally produced and maintained by dynamo action. The extreme temperature and density contrasts and stratifications are emphasized in connection with turbulence in the interstellar medium and in stars with outer convection zones, respectively. In many cases turbulence plays an essential role in facilitating enhanced transport of mass, momentum, energy and magnetic fields in terms of the corresponding coarse-grained mean fields. Those transport properties are usually strongly modified by anisotropies and often completely new effects emerge in such a description that have no correspondence in terms of the original (non-coarse-grained) fields. © 2011 IOP Publishing Ltd.

Demant J.,University of Aarhus | Torronen J.,University of Stockholm
Substance Use and Misuse | Year: 2011

A traditional heavy intoxication-oriented drinking style, "heroic drinking," is a central drinking practice in Denmark and Finland, especially among men. However, it seems that another drinking style leading to intoxication, "playful drinking," has become more prevalent in Denmark as well as in Finland. Playful drinking is characterized by self-presentations in diverse forms of game situations in which you need to play with different aspects of social and bodily styles. We approach the positions of heroic drinking and playful drinking among young adults (between 17 and 23 years) in Denmark and Finland by analyzing how they discuss these two drinking styles in focus groups (N = 16). © 2011 Informa Healthcare USA, Inc.

Wahlberg N.,University of Turku | Wheat C.W.,University of Stockholm | Pena C.,University of Turku
PLoS ONE | Year: 2013

The macroevolutionary history of the megadiverse insect order Lepidoptera remains little-known, yet coevolutionary dynamics with their angiospermous host plants are thought to have influenced their diversification significantly. We estimate the divergence times of all higher-level lineages of Lepidoptera, including most extant families. We find that the diversification of major lineages in Lepidoptera are approximately equal in age to the crown group of angiosperms and that there appear to have been three significant increases in diversification rates among Lepidoptera over evolutionary time: 1) at the origin of the crown group of Ditrysia about 150 million years ago (mya), 2) at the origin of the stem group of Apoditrysia about 120 mya and finally 3) a spectacular increase at the origin of the stem group of the quadrifid noctuoids about 70 mya. In addition, there appears to be a significant increase in diversification rate in multiple lineages around 90 mya, which is concordant with the radiation of angiosperms. Almost all extant families appear to have begun diversifying soon after the Cretaceous/Paleogene event 65.51 mya. © 2013 Wahlberg et al.

Hahn T.,University of Stockholm
Ecology and Society | Year: 2011

Governance networks play an increasingly important role in ecosystem management. The collaboration within these governance networks can be formalized or informal, top-down or bottom-up, and designed or self-organized. Informal self-organized governance networks may increase legitimacy if a variety of stakeholders are involved, but at the same time, accountability becomes blurred when decisions are taken. Basically, democratic accountability refers to ways in which citizens can control their government and the mechanisms for doing so. Scholars in ecosystem management are generally positive to policy/ governance networks and emphasize its potential for enhancing social learning, adaptability, and resilience in social-ecological systems. Political scientists, on the other hand, have emphasized the risk that the public interest may be threatened by governance networks. I describe and analyze the multilevel governance network of Kristianstads Vattenrike Biosphere Reserve (KVBR) in Southern Sweden, with the aim of understanding whether and how accountability is secured in the governance network and its relation to representative democracy. The analysis suggests that the governance network of KVBR complements representative democracy. It deals mainly with "low politics"; the learning and policy directions are developed in the governance network, but the decisions are embedded in representative democratic structures. Because several organizations and agencies co-own the process and are committed to the outcomes, there is a shared or extended accountability. A recent large investment in KVBR caused a major crisis at the municipal level, fueled by the financial crisis. The higher levels of the governance network, however, served as a social memory and enhanced resilience of the present biosphere development trajectory. For self-organized networks, legitimacy is the bridge between adaptability and accountability; accountability is secured as long as the adaptive governance network performs well, i.e., is perceived as legitimate. Governing and ensuring accountability of governance networks, without hampering their flexibility, adaptability, and innovativeness, represents a new challenge for the modern state. © 2011 by the author(s).

Glantz P.,University of Stockholm
Environmental Research Letters | Year: 2010

The optical and microphysical properties of low level marine clouds, presented over the Norwegian Sea and Barents Sea, have been investigated for the period 2000-2006. The air masses were transported for more or less seven days over the warmer North Atlantic before they arrived at the area investigated. The main focus in this study is on investigating the relationship between cloud optical thickness (COT) and surface wind speed (U10 m) using satellite retrievals in combination with operational meteorological data. A relatively strong correlation (R2 = 0.97) is obtained for wind speeds up to 12 m s-1, in air masses that were probably to a major degree influenced by wind shears and to a minor degree by buoyancy. The relationship (U2.5) is also in between those most commonly found in the literature for water vapor (U∼1) and sea salt (U∼3.4). The present results highlight the magnitude of marine sea-spray influence on COT and their global climatic importance. © 2010 IOP Publishing Ltd.

Linder M.,Uppsala University | Sennblad B.,Albanova University Center | Sennblad B.,University of Stockholm
Systematic Biology | Year: 2011

We have evaluated the performance of two classes of probabilistic models for substitution rate variation over phylogenetic trees. In the first class, branch rates are considered to be independent and identically distributed (i.i.d.) stochastic variables. Three versions with respect to the underlying distribution (Gamma, Inverse Gaussian, and LogNormal) are considered. The i.i.d. models are compared with the autocorrelated (AC) model, where rates of adjacent nodes in the tree are AC, so that a node rate is LogNormal distributed around the rate of the parent node. The performance of different models is evaluated using three empirical data sets. For all data sets, it was clear that all tested models extracted substantial knowledge from data when posterior divergence time distributions were compared with the prior distributions and, furthermore, that they clearly outperformed a molecular clock. Moreover, the descriptive power of the i.i.d. models, as evaluated by Bayes factors, was either equal to or clearly better than that of the AC model. The latter effect increased with extended taxon sampling. Likewise, under none of the models could we find compelling evidence, in any of the data sets, for rate correlation between adjacent branches/nodes. These findings challenge previous suggestions of universality of autocorrelation in sequence evolution. We also performed an additional comparison with a divergence time prior including calibration information from fossil evidence. Adding fossil information to the prior had negligible effect on Bayes factors and mainly affected the width of the posterior distribution of the divergence times, whereas the relative position of the mean divergence times were largely unaffected. © 2011 The Author(s).

Background: Previous research has suggested a positive risk-relationship between volume of consumption and adverse behavioral and social consequences of drinking. However, because the risk-relationship may be modified by factors such as pattern of drinking, attributes of social drinking contexts, and drunken comportment, the shape of the risk-function appear to be contingent upon the larger cultural context of drinking. Methods: In this article, I use graphical risk-curve analyses and model estimations to assess how the risk of experiencing alcohol-related problems is associated with self-reported volume of alcohol consumption in the 3 Baltic countries (Estonia, Latvia, and Lithuania) as well as Sweden and Italy. The analysis utilized data from 2 general population surveys (including Sweden plus Italy and the Baltic countries, respectively) with approximately 1,000 respondents from each country. Results: The risk-curves for the 3 Baltic countries and Sweden were fairly parallel and clearly steeper than that for Italy. In the logistic regression models, the country-specific Baltic estimates were not entirely homogenous; for Estonia and Latvia, the estimates were similar to that for Sweden and significantly larger than that for Italy, whereas the estimate for Lithuania did not differ significantly from that for Italy. However, the negative binominal regression models suggested that increasing volume of consumption is associated with the risk of experiencing a larger number of different problems in all 3 Baltic countries and Sweden than in Italy. Overall, the result thus suggests that there is a significant relationship between volume of consumption and risk of experiencing alcohol-related problems in all countries but that the relationship generally is stronger in the Baltic countries and Sweden than in Italy. Conclusions: The results were largely in line with the hypothesis of a European north to south gradient in the strength of the risk-relationship, but also add that most Baltic countries may be placed alongside the Nordic countries in this context. Because only volume of consumption is considered, the results cannot be used to specify which factors and mechanisms that actually modify the shape of the risk-function in each culture. © 2011 by the Research Society on Alcoholism.

Furberg E.,University of Stockholm
Journal of Medicine and Philosophy | Year: 2012

The personal identity problem expresses the worry that due to disrupted psychological continuity, one person's advance directive could be used to determine the care of a different person. Even ethicists, who strongly question the possibility of the scenario depicted by the proponents of the personal identity problem, often consider it to be a very potent objection to the use of advance directives. Aiming to question this assumption, I, in this paper, discuss the personal identity problem's relevance to the moral force of advance directives. By putting the personal identity argument in relation to two different normative frameworks, I aim to show that whether or not the personal identity problem is relevant to the moral force of advance directives, and further, in what way it is relevant, depends entirely on what normative reasons we have for respecting advance directives in the first place. © The Author 2012.

Karlsson J.,University of Stockholm | Teixeira J.,Jet Propulsion Laboratory
Journal of Climate | Year: 2014

Air advected equatorward by the trade winds off the coast of California is associated with decreasing cloud cover and is subjected to increasingly warmer sea surface temperatures. These gradients imply large gradients in the surface energy fluxes. Based on the surface energy balance and on the assumption of a small net surface energy flux, which is supported by reanalysis data, a cloud cover model of the climatological stratocumulus to cumulus transition in the northeastern subtropical Pacific Ocean is developed. Using climatological meteorological surface variables, the model, despite its simplicity, is able to describe the transition from stratocumulus to cumulus reasonably well in terms of cloud cover. © 2014 American Meteorological Society.

Abstract The sarcoplasmic Ca2 +-ATPase (SERCA1a) forms two phosphoenzyme intermediates during Ca2 + pumping. The second intermediate E2P hydrolyzes rapidly, which is essential for the rapid removal of Ca2 + from the cytosol of muscle cells. The present work studies whether a weakening of the scissile PO bond in the E2P ground state facilitates dephosphorylation. To this end, the experimentally known vibrational spectrum of the E2P phosphate group was calculated with density functional theory (DFT) using structural models at two levels of structural complexity: (i) Models of acetyl phosphate in simple environments and (ii) ~ 150 atom models of the catalytic site. It was found that the enzyme environment distorts the structure of the phosphate group: one of the terminal PO bonds is shorter in the catalytic site indicating weaker interactions than in water. However, the bond that bridges phosphate and Asp351 is unaffected. This indicates that the scissile PO bond is not weakened by the enzyme environment of E2P. A second finding was that the catalytic site of the E2P state in aqueous solution appears to adopt a structure as in the crystals with BeF3-, where the ATPase is in a non-reactive conformation. The reactant state of the dephosphorylation reaction differs from the E2P ground state: Glu183 faces Asp351 and positions the attacking water molecule. This state has a 0.04 Å longer, and thus weaker, bridging PO bond. The reactant state is not detected in our experiments, indicating that its energy is at least 1 kcal/mol higher than that of the E2P ground state. © 2015 Elsevier B.V.

Kunkel U.,University of Bayreuth | Radke M.,University of Bayreuth | Radke M.,University of Stockholm
Water Research | Year: 2012

Pharmaceutical residues are commonly detected organic micropollutants in the aquatic environment. Their actual fate in rivers is still incompletely understood as their elimination is highly substance specific and studies often report contradictory results. To elucidate the ceiling of attenuation rates of pharmaceuticals in rivers we carried out a study at a river with favorable conditions for the elimination of organic micropollutants.Experiments were carried out at a small stream in Germany. Composite samples were taken at both ends of a 12.5 km long river stretch located downstream of a sewage treatment plant and analyzed for 10 pharmaceuticals. Moreover, pore water samples were taken and in situ photolysis experiments at several sites within the river stretch were performed to assess the importance of these individual elimination mechanisms.Pharmaceutical concentration in the surface water at the first sampling site ranged from 3.5 ng L-1 for propranolol to 1400 ng L-1 for diclofenac. In comparison to carbamazepine which was used as persistent tracer, all other pharmaceuticals were attenuated along the river stretch. Their elimination was higher in a sunny, dry weather period (period I) compared to a period with elevated discharge after a heavy rainfall (period II). Overall, the measured elimination rates ranged from 25% for sulfamethoxazole (period II) to 70% for propranolol (period I). Photolysis was only a relevant elimination process for diclofenac and potentially also for sotalol; for these compounds phototransformation half-life times of some hours were determined in the unshaded parts of the river. Biotransformation in the sediments was also an important attenuation process since the concentrations of the other pharmaceuticals in the sediments decreased relative to carbamazepine with depth. For the chiral betablocker metoprolol this biotransformation was also confirmed by a decrease in the enantiomer fractionation from 0.49 at site A to 0.43 at site B and to <0.40 in the deeper sediments. © 2012 Elsevier Ltd.

Siegbahn P.E.M.,University of Stockholm | Borowski T.,Polish Academy of Sciences
Faraday Discussions | Year: 2011

Two previous studies on the mechanism of tyrosinase have given quite conflicting results. In a QM-only study using a rather small model, a mechanism was suggested in which the tyrosine proton is removed before catalysis. This was followed by catalytic cycles where a superoxo ligand attacks the phenolate ring. In another, more recent study, at the QM/MM level including the entire protein in the model, a quite different mechanism was instead advocated where a bridging O2H ligand was homolytically cleaved. That mechanism was rejected in the earlier QM-only study as having a prohibitively large barrier for O-O bond cleavage. In the present study, this discrepancy between the previous studies is investigated by new QM-only and QM/MM calculations. © 2011 The Royal Society of Chemistry.

Heidbuchel I.,University of Arizona | Troch P.A.,University of Arizona | Lyon S.W.,University of Stockholm | Weiler M.,Albert Ludwigs University of Freiburg
Water Resources Research | Year: 2012

The transit time of water is an important indicator of catchment functioning and affects many biological and geochemical processes. Water entering a catchment at one point in time is composed of water molecules that will spend different amounts of time in the catchment before exiting. The next water input pulse can exhibit a totally different distribution of transit times. The distribution of water transit times is thus best characterized by a time-variable probability density function. It is often assumed, however, that the variability of the transit time distribution is negligible and that catchments can be characterized with a unique transit time distribution. In many cases this assumption is not valid because of variations in precipitation, evapotranspiration, and catchment water storage and associated (de)activation of dominant flow paths. This paper presents a general method to estimate the time-variable transit time distribution of catchment waters. Application of the method using several years of rainfall-runoff and stable water isotope data yields an ensemble of transit time distributions with different moments. The combined probability density function represents the master transit time distribution and characterizes the intra-annual and interannual variability of catchment storage and flow paths. Comparing the derived master transit time distributions of two research catchments (one humid and one semiarid) reveals differences in dominant hydrologic processes and dynamic water storage behavior, with the semiarid catchment generally reacting slower to precipitation events and containing a lower fraction of preevent water in the immediate hydrologic response. © 2012. American Geophysical Union. All Rights Reserved.

Ronquist F.,Swedish Museum of Natural History | Teslenko M.,Swedish Museum of Natural History | Van Der Mark P.,Florida State University | Ayres D.L.,University of Maryland University College | And 6 more authors.
Systematic Biology | Year: 2012

Since its introduction in 2001, MrBayes has grown in popularity as a software package for Bayesian phylogenetic inference using Markov chain Monte Carlo (MCMC) methods. With this note, we announce the release of version 3.2, a major upgrade to the latest official release presented in 2003. The new version provides convergence diagnostics and allows multiple analyses to be run in parallel with convergence progress monitored on the fly. The introduction of new proposals and automatic optimization of tuning parameters has improved convergence for many problems. The new version also sports significantly faster likelihood calculations through streaming single-instruction-multiple-data extensions (SSE) and support of the BEAGLE library, allowing likelihood calculations to be delegated to graphics processing units (GPUs) on compatible hardware. Speedup factors range from around 2 with SSE code to more than 50 with BEAGLE for codon problems. Checkpointing across all models allows long runs to be completed even when an analysis is prematurely terminated. New models include relaxed clocks, dating, model averaging across time-reversible substitution models, and support for hard, negative, and partial (backbone) tree constraints. Inference of species trees from gene trees is supported by full incorporation of the Bayesian estimation of species trees (BEST) algorithms. Marginal model likelihoods for Bayes factor tests can be estimated accurately across the entire model space using the stepping stone method. The new version provides more output options than previously, including samples of ancestral states, site rates, site dN/dS rations, branch rates, and node dates. A wide range of statistics on tree parameters can also be output for visualization in FigTree and compatible software. © 2012 The Author(s).

Osterblom H.,University of British Columbia | Osterblom H.,University of Stockholm | Sumaila U.R.,University of British Columbia
Global Environmental Change | Year: 2011

Illegal, unregulated and unreported (IUU) fishing is a challenging form of non-compliance in many marine ecosystems. IUU fishing has attracted substantial political attention in the Southern Ocean, where a series of crises created windows of opportunity for change. A crises-response framework was used for examining these dynamics between 1995 and 2009. Crises were defined in relation to their perceived threat, decision time and surprise. Published material was combined with the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLRs) expert interviews, to evaluate changing perceptions of IUU fishing and corresponding actions. A first crisis led to an increased use of informal shortcuts and a concentration of power. A second crisis created windows of opportunities for policy entrepreneurs and stimulated policy innovation. A third crisis led to the implementation of existing contingency plans. These responses were consistent with predictions from the crisis-response framework used. The series of crises threatened the credibility of CCAMLR and changed the incentives for engaging in coalitions, which led to the development of both management and enforcement approaches to compliance. State and non-state actors became increasingly involved in developing these diverse compliance mechanisms, thereby actively contributing to the adaptive capacity of CCAMLR. Synergies between fisheries industry, environmental conservation, and state sovereignty interests were effectively utilized. Individual actors, organizations and countries providing leadership had strong incentives for doing so. Trust and reputation was important for the compliance mechanisms leading to a substantial reduction of IUU fishing. © 2011 Elsevier Ltd.

Larson J.,University of Stockholm
EPL | Year: 2010

We propose a scheme in which the Lipkin-Meshkov-Glick model is realized within a circuit QED system. An array of N superconducting qubits interacts with a driven cavity mode. In the dispersive regime, the cavity mode is adiabatically eliminated generating an effective model for the qubits alone. The characteristic long-range order of the Lipkin-Meshkov-Glick model is here mediated by the cavity field. For a closed qubit system, the inherent second-order phase transition of the qubits is reflected in the intensity of the output cavity field. In the broken symmetry phase, the many-body ground state is highly entangled. Relaxation of the qubits is analyzed within a mean-field treatment. The second-order phase transition is lost, while new bistable regimes occur. © 2010 Europhysics Letters Association.

Szabo K.J.,University of Stockholm
Journal of Molecular Catalysis A: Chemical | Year: 2010

DFT modeling studies were performed for oxidative addition of hypervalent iodonium salts to Pd(II) pincer-complexes. The focus was directed to steric and electronic effects, which are important in the key-step of the Pd(II)/Pd(IV) redox cycle based catalytic reactions. © 2010 Elsevier B.V. All rights reserved.

Gaar D.,University of Bern | Preusser F.,University of Stockholm
Quaternary Geochronology | Year: 2012

Remains of at least two individuals of woolly mammoths (Mammuthus primigenius) were discovered after blastings in a limestone quarry located on the southern slope of the Jura Mountains, northern Switzerland. During the subsequent excavation two blocks were taken for luminescence dating from the sediment surrounding the remains; the deposits are interpreted to represent the filling of a karst hole. Luminescence dates on the polymineral and purified quartz fine grain fraction are compared to those obtained for single grains of quartz and small aliquots of quartz as well as feldspar coarse grains. All approaches give ages consistent within the dating uncertainties and are interpreted to prove the robustness of the dating results. The age of the sediment of ca. 63 ka indicates deposition during Marine Isotope Stage (MIS) 4, thus, during a time when Switzerland experienced rather cold climatic conditions. These are some of the oldest numerically dated woolly mammoth remains of Europe. © 2012 Elsevier B.V.

Manor O.,Hebrew University of Jerusalem | Koupil I.,University of Stockholm
International Journal of Epidemiology | Year: 2010

Background: Individuals who are small at birth are at increased risk of cardiovascular disease later in life. To enhance understanding of the mechanisms underlying this association we examined the link between infants' birth weight and mortality in their parents and grandparents. Methods: We used the Uppsala birth cohort to examine all-cause and circulatory disease mortality among 14 129 mothers, 13 863 fathers, 3992 maternal and 3910 paternal grandmothers and 3896 maternal and 3798 paternal grandfathers. Follow-up time lasted up to 2002 with median of 21.6 years for parents and 47.8 years for grandparents. Results: Hazard models controlling for socio-demographic characteristics indicated an inverse linear association between offspring's birth weight and maternal circulatory disease mortality [hazards ratio (HR) = 0.74; 95% confidence interval (CI): 0.56-0.99]. No association was observed for fathers. The association between birth weight of grandchildren and grandparental mortality varied. No association was detected for maternal grandmothers for the whole period examined; only among grandmothers whose grandchild was born prior to 1977 was a U-shaped association observed for circulatory disease mortality. There was a U-shaped association between birth weight of grandchildren and maternal grandfather's overall and circulatory disease mortality (quadratic term: HR = 1.05; 95% CI: 1.01-1.09). An inverse linear relationship was found for circulatory disease mortality in paternal grandmothers (HR = 0.93; 95% CI: 0.85-1.00). For paternal grandfathers there was an inverse association between grandchildren's birth weight and overall mortality; for circulatory disease mortality an effect was found only for grandfathers whose grandchild was born prior to 1977. Conclusions: We showed, for the first time, associations between fetal growth in one generation and mortality in the previous two generations. Genetic and/or environmental pathways accounting for these associations should be further explored. Published by Oxford University Press on behalf of the International Epidemiological Association © The Author 2010; all rights reserved.

We present a strategy, referred to as "split network" analysis, for assessing the average network polymerization (r F) and mean number of bridging oxygen (BO) atoms (N̄ BO F) for each individual network former F in multi-component oxide-based glasses, primarily targeting those involving Al, B, P and Si. This requires a priori knowledge about the parameters {r F, N̄ BO F} of all network builders, but one, whose values are deduced by the split network procedure. We illustrate split-network concepts for establishing composition/structure/bioactivity correlations in Na-Ca-Si-P-O glasses. The cooperating influences on the bioactivity from the average polymerization degree of the silicate network and the amounts of orthophosphate and sodium ions are discussed. © 2010 Elsevier B.V.

Lateef D.M.,U.S. National Institute of Diabetes and Digestive and Kidney Diseases | Abreu-Vieira G.,University of Stockholm | Xiao C.,U.S. National Institute of Diabetes and Digestive and Kidney Diseases | Reitman M.L.,U.S. National Institute of Diabetes and Digestive and Kidney Diseases
American Journal of Physiology - Endocrinology and Metabolism | Year: 2014

Bombesin receptor subtype-3 (BRS-3) regulates energy homeostasis, with Brs3 knockout (Brs3-/y) mice being hypometabolic, hypothermic, and hyperphagic and developing obesity. We now report that the reduced body temperature is more readily detected if body temperature is analyzed as a function of physical activity level and light/dark phase. Physical activity level correlated best with body temperature 4 min later. The Brs3-/y metabolic phenotype is not due to intrinsically impaired brown adipose tissue function or in the communication of sympathetic signals from the brain to brown adipose tissue, since Brs3-/y mice have intact thermogenic responses to stress, acute cold exposure, and β3-adrenergic activation, and Brs3-/y mice prefer a cooler environment. Treatment with the BRS-3 agonist MK-5046 increased brown adipose tissue temperature and body temperature in wild-type but not Brs3-/y mice. Intrahypothalamic infusion of MK-5046 increased body temperature. These data indicate that the BRS-3 regulation of body temperature is via a central mechanism, upstream of sympathetic efferents. The reduced body temperature in Brs3-/y mice is due to altered regulation of energy homeostasis affecting higher center regulation of body temperature, rather than an intrinsic defect in brown adipose tissue.

AIM - While gender differences in substance use/problems have been found to be smaller in more gender-equal countries such as Sweden, gender-specific norms still prevail, and women's (mis)use continues to be more condemned than men's. This article analyses and discusses similarities and differences between the sexes in alcohol and drug treatment in terms of men's and women's treatment experiences, consumption/problems, social situation, and life-domain problems. METHOD - 1865 respondents were interviewed (structured interview) at the beginning of a new treatment episode in 2000-2002 in Stockholm County (sample representative of those starting a new treatment episode for alcohol or drug problems in Stockholm County). Responses are cross-tabulated by sex and multivariate logistic regression is used to predict whether men or women have more severe problems in various life domains of the Addiction Severity Index (ASI composite scores). RESULTS - Bivariate analyses showed that women and men differ significantly in their treatment experiences. Women are more likely to have contact with mental health services, whereas men tend to deal more with the criminal justice system. The sexes do not differ in alcohol and drug problem severity, but women are more likely to have problems with pharmaceuticals. In contrast to the hypothesis, it turned out that men, not women, are more marginalised as concerns housing, income, family situation, lack of friends. Women report more problems related to family, social life and mental/physical health, while men report higher criminality and financial problems. CONCLUSIONS - There are no gender differences among the clients in the treatment system when it comes to substance problem severity but differences occur concerning the clients' social situation and different life-domain problems. As men are more socially exposed a focus on women may obscure problems among men.

Ye Z.,Hoganas AB | Noreus D.,University of Stockholm
Journal of Power Sources | Year: 2012

The kinetics of oxygen and hydrogen gas recombination on the metal hydride electrode in a NiMH cell is investigate as function of gas pressure, temperature, cycling and a hydrophobic additive. Both oxygen and hydrogen gas recombination rates in the NiMH cells are found to be linearly proportional to the gas pressure, indicating that surface processes with a constant number of reaction sites could be the rate limiting step. The rate of oxygen gas recombination is, however, more than 10 times faster than that of hydrogen at the same pressure. As the temperature increases, both reaction rates increase very rapidly, even though the solubilities of the gases in the KOH electrolyte decrease with temperature. The activation energies for oxygen and hydrogen gas recombination are 32.6 kJ mol -1 and 27.0 kJ mol -1, respectively. The reactions rates also increase as the cells are cycled. This indicates, that the number of active sites increases, as the surface area increases, due to the continuously decrepitating of the alloy particles. The hydrogen gas absorption rate increases dramatically after a large number of cycles due the drying of the MH electrode. A hydrophobic PTFE additive in the MH electrode can significantly improve hydrogen absorption efficiency in NiMH cells. © 2011 Elsevier Ltd. All rights reserved. All rights reserved.

Liden G.,University of Stockholm
Annals of Occupational Hygiene | Year: 2011

In 2010, the European Commission held a short consultation on a proposed definition for nanomaterials, to be used in European Union legislation and programmes. This was in response to a European Parliament resolution, and the definition followed a proposal by one of the Commission's scientific committees. The definition has three parts: on size distribution, size of internal structural elements, and surface area; a material caught by any of these parts meets the definition. There are a number of problems. The definition seems to be written with engineered nanomaterials in mind but as written applies to non-supplied materials, such as smokes. The structural element component seems to capture items such as sunscreen and tennis rackets, which include nanomaterials. Use of the definition will require some international standards, which have yet to be written and which will involve some difficult decisions. It is understandable why there are both size and surface area requirements, but they are not wholly consistent. The Commission plans a further consultation in 2012, but it might be better to delay this until after the standardisation work.

Lowick S.E.,University of Bern | Trauerstein M.,University of Bern | Preusser F.,University of Stockholm
Quaternary Geochronology | Year: 2012

The polymineral fine grain fraction of a set of ten known age samples were used to test the suitability of elevated temperature post-IR infrared stimulated luminescence (pIRIR) to date waterlain sediments in Switzerland. Equivalent Dose (D e) values were obtained using elevated temperatures of 225°C (pIRIR 225) and 290°C (pIRIR 290) and IRSL 50/225 (preceding measurement of pIRIR 225), and these displayed a systematic increase with increasing stimulation temperature, which brought those derived from the pIRIR protocols into saturation for the older half of the samples (>100ka). Significant residuals were recorded for the pIRIR signals, and these were found to further increase following attenuation of the bleaching source confirming that these signals are harder to bleach than the IRSL measured at 50°C. Fading tests recorded g-values of between 1 and 4%, and displayed no obvious decrease with increasing stimulation temperature. For the younger half of the samples, fading corrected ages for all protocols resulted in overestimation compared to robust independent dating for all samples, and draw into question the relationship of fading measured in a laboratory generated signal to that which is naturally generated. Uncorrected IRSL 50/225 ages for all samples were in good agreement with independent dating, but still displayed a general overestimation using pIRIR signals. These overestimations may largely be due to the significant residual doses resulting from the harder to bleach nature of the elevated temperature signal, and present a considerable problem when dating waterlain sediments. A considerable challenge when using the pIRIR signal is to be able to separate the effects of both residual doses and fading and confirm that one is not masking the other. Despite this, the pIRIR protocols were successful at one site, although they offered no benefit compared to dating with more conventional luminescence signals. A comparison of D e values derived from a standard IRSL signal to that from IRSL 50/225, suggest that the latter overestimates by ~10% due to a decrease in sensitivity of the sample prior to measurement of the test dose. © 2011 Elsevier B.V.

Patacchini E.,University Rome | Zenou Y.,University of Stockholm
Journal of Regional Science | Year: 2011

We analyze the intergenerational transmission of education focusing on the interplay between family and neighborhood effects. We develop a theoretical model suggesting that both neighborhood quality and parental effort are of importance for the education attained by children. This model proposes a mechanism explaining why and how they are of importance, distinguishing between high- and low-educated parents. We then bring this model to the data using a longitudinal dataset in Britain. The available information on social housing in big cities allows us to identify the role of neighborhood in educational outcomes. We find that the better the quality of the neighborhood, the higher is the parents' involvement in their children's education. A novel finding with respect to previous U.S. studies is that family is of importance for children with highly educated parents while it is the community that is crucial for the educational achievement of children from low-educated families. © 2011, Wiley Periodicals, Inc.

Ornberg J.C.,University of Stockholm
Drugs and Alcohol Today | Year: 2013

Purpose: This paper aims to analyse Swedish tobacco policy, especially in relation to EU tobacco regulation. The paper also seeks to review the arguments and the scientific support presented in the debate around Swedish snus, setting it in the context of future EU regulation on tobacco. Design/methodology/approach: The article draws on previous research, official documents and newspaper articles to examine tobacco policy development on a national and EU level. Findings: The paper shows that the so-called Swedish experience has led to a somewhat ambivalent political attitude towards tobacco policy. The Swedish case of snus also demonstrates the EU as a political and regulatory force in national policymaking and how different economic and political interests are using scientifically based arguments to advance goals of their own. The paper argues that political measures are dictated by ideology and political considerations, which are themselves supported by ambiguous scientific results. Harm reduction is used as a political tool in a debate which extends well beyond public health concerns. Originality/value: This paper contributes to research on tobacco policy in general and on Swedish snus in particular. The paper also puts the snus question in a broader context of national public health policy and EU regulation. © Emerald Group Publishing Limited.

Gorokhova E.,University of Stockholm
Limnology and Oceanography: Methods | Year: 2010

A simplified method for viability analysis of zooplankton eggs by staining of nonviable eggs with a fluorescent nucleic acid stain TO-PRO-1 iodide is proposed here as a further development of fluorescence-based egg viability assays. This is one-step analysis with no intermediate steps for chorion removal. The method was calibrated using predetermined mixtures of viable and nonviable eggs (rotifers and copepods), and validated using hatching experiments (copepods) and egg development assay (cladocerans) as reference measurements. In these tests, eggs of several zooplankton species, Brachionus plicatilis (Rotatoria), Daphnia magna (Cladocera), Nitocra spinipes (Harpacticoida), Acartia tonsa (Calanoida), were used. Moreover, staining efficiency was not affected by storage of samples for up to 1 month in -80°C, making the assay suitable for egg viability assessment in field and laboratory studies. To illustrate usefulness of the method, it was applied to evaluate how absence of re-mating affects production of viable eggs in females of A. bifilosa (Calanoida). In females separated from males, proportion of sterile eggs increased in 3 d after the separation and no viable eggs were produced after 5 d. The effects of mating frequency on egg viability are important to understand when designing egg production experiments and interpreting field data on egg viability in populations with skewed sex ratios. © 2010, by the American Society of Limnology and Oceanography, Inc.

Eden M.,University of Stockholm
Annual Reports on the Progress of Chemistry - Section C | Year: 2012

Solid-state nuclear magnetic resonance (NMR) spectroscopy offers an array of options for exploring structural order of amorphous materials both over short (≲0.3 nm) and medium (≲1 nm) ranges. We review the advances reported in the literature for characterizing the structures of oxide-based glasses over roughly the past 15 years. Besides describing the current understanding of basic short-range structural aspects of binary and ternary glass systems that typically involve a single glass modifier and one (silicates and phosphates) or two (e.g., aluminosilicates, aluminophosphates and silicophosphates) network formers, we focus on illustrating the progress made for revealing intermediate-range structural order, such as extracting information about connectivities among the basic building blocks in the glass networks and how more extended structural motifs may be identified. By assuming only relatively basic background in solid-state NMR and/or the structure of glasses, we hope this review will appeal to newcomers of either area. © 2012 The Royal Society of Chemistry.

Blomquist J.,University of Stockholm
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2010

Mössbauer measurements have been made on a series of stainless steel absorbers of different type and thickness. The analysis has been performed with different line shape approximations to illuminate the sensitivity to the method used, with focus on the recoilless fraction f. © 2009 Elsevier B.V. All rights reserved.

Needham P.,University of Stockholm
Studies in History and Philosophy of Science Part B - Studies in History and Philosophy of Modern Physics | Year: 2010

Despite all the criticism showered on Nagel's classic account of reduction, it meets a fundamental desideratum in an analysis of reduction that is difficult to question, namely of providing for a proper identification of the reducing theory. This is not clearly accommodated in radically different accounts. However, the same feature leads me to question Nagel's claim that the reducing theory can be separated from the putative bridge laws, and thus to question his notion of heterogeneous reduction. A further corollary to the requirement that all the necessary conditions be incorporated in an adequate formulation of the putative reducing theory is that the standard example of gas temperature is not reducible to average molecular kinetic energy. As originally conceived, Nagel's conception of reduction takes no account of approximate reasoning and this failure has certainly restricted its applicability, perhaps to the point of making it unrealistic as a model of reduction in science. I suggest approximation can be accommodated by weakening the original requirement of deduction without jeopardizing the fundamental desideratum. Finally, I turn to briefly consider the idea sometimes raised of the ontological reducibility of chemistry. © 2009 Elsevier Ltd.

Granholm V.,University of Stockholm
BMC bioinformatics | Year: 2012

Peptides are routinely identified from mass spectrometry-based proteomics experiments by matching observed spectra to peptides derived from protein databases. The error rates of these identifications can be estimated by target-decoy analysis, which involves matching spectra to shuffled or reversed peptides. Besides estimating error rates, decoy searches can be used by semi-supervised machine learning algorithms to increase the number of confidently identified peptides. As for all machine learning algorithms, however, the results must be validated to avoid issues such as overfitting or biased learning, which would produce unreliable peptide identifications. Here, we discuss how the target-decoy method is employed in machine learning for shotgun proteomics, focusing on how the results can be validated by cross-validation, a frequently used validation scheme in machine learning. We also use simulated data to demonstrate the proposed cross-validation scheme's ability to detect overfitting.

Christiansen and Ljungqvist have presented an extratropical NH temperature reconstruction using a method (LOC) that they claim "preserves" low-frequency variability, at the expense of exaggerated highfrequency variability. Using theoretical arguments and a pseudoproxy experiment, it is demonstrated here that the LOC method is not guaranteed to preserve variability at any frequency. Rather, LOC reconstructions will have more variance than true large-scale temperature averages at all frequencies. This variance inflation, however, can be negligible at those frequencies where the noise variance in individual proxies is small enough to be effectively cancelled when computing an average over the available proxies. Because the proxy noise variance at low frequencies cannot be directly estimated, and thus has to be regarded as unknown, it is safer to regard a reconstruction with the LOC method as providing an estimate of the upper bound of the large-scale low-frequency temperature variability rather than one with a correct estimate of this variance. © 2012 American Meteorological Society.

Vehkamaki H.,University of Helsinki | Riipinen I.,University of Stockholm
Chemical Society Reviews | Year: 2012

In this tutorial review we summarize the standard approaches to describe aerosol formation from atmospheric vapours and subsequent growth - with a particular emphasis on the interplay between equilibrium thermodynamics and non-equilibrium transport. We review the use of thermodynamics in describing phase equilibria and formation of aerosol particles from supersaturated vapour via nucleation. We also discuss the kinetics of cluster formation and transport phenomena, which are used to describe dynamic mass transport between the gaseous and condensed phases in a non-equilibrium system. Finally, we put these theories into the context of atmospheric observations of aerosol formation and growth. © 2012 The Royal Society of Chemistry.

Lyubartsev A.P.,University of Stockholm | Rabinovich A.L.,Institute of Biology
Soft Matter | Year: 2011

Rapid development of computer power during the last decade has made molecular simulations of lipid bilayers feasible for many research groups, which, together with the growing general interest in investigations of these very important biological systems has lead to tremendous increase of the number of research on the computational modeling of lipid bilayers. In this review, we give account of the recent progress in computer simulations of lipid bilayers covering mainly the period of the last 5 years, and covering several selected subjects: development of the force fields for lipid bilayer simulations, studies of the role of lipid unsaturation, the effect of cholesterol and other inclusions on properties of the bilayer, and use of coarse-grained models. © 2011 The Royal Society of Chemistry.

Laurell J.,University of Stockholm
Criminal behaviour and mental health : CBMH | Year: 2010

There is a recognised relationship between psychopathy and instrumental violence, but not all violence by people who meet the criteria for psychopathy is instrumental. Our aims were to compare offence types among forensic psychiatric patients with and without the Psychopathy Checklist: Screening Version (PCL: SV) criteria for psychopathy. Our specific questions were whether factor 1 - the interpersonal affective dimension - was related to instrumentality and on severity of the violent crime. Our hypothesis was that the relationship between psychopathy and instrumental violence would be dependent on the severity of the violent crime. Sixty-five male patients at the forensic psychiatric hospital in Sundsvall, all with a violent criminal history, were assessed for psychopathy through interview and records using the PCL: SV. Severity and the instrumentality of their previous violence were coded using the Cornell coding guide for violent incidents. The interpersonal features of psychopathy (the interpersonal facet), and only the interpersonal features were significantly associated with instrumentality and severity of violence. Instrumentality was also significantly related to the severity of the violence, independent of psychopathy score. The results indicated that, at least among forensic psychiatric patients, planning is more likely than not with respect to serious crimes. The specific link between interpersonal features of psychopathy and instrumental and severe violence suggests potential clinical value in recognising subtypes of psychopathy. © 2010 John Wiley & Sons, Ltd.

Jonsson C.,University of Stockholm
Journal of Pragmatics | Year: 2010

The present study examines functions of code-switching in Chicano theater, i.e. in writing intended for performance. The investigation focuses on local functions of code-switching. These are functions that can be seen in the text and, as a consequence, can be regarded as meaningful for the audience of the plays. In the study these functions are examined, focusing on five loci in which code-switching is frequent, namely quotations, interjections, reiterations, 'gaps' and word/language play. The data of the study consists of three published plays by a Chicana playwright. The study concludes that code-switching fills creative, artistic and stylistic functions in the plays and that it can be used to add emphasis to a certain word or passage, to add another level of meaning, to deepen/intensify a meaning, to clarify, to evoke richer images and to instruct the audience about a particular concept. Code-switching is also used to mark closeness, familiarity, to emphasize bonds, and to include or, on the contrary, to mark distance, break bonds and exclude. Complex identities of the characters as well as the plots of the plays are constructed and developed by means of language. Code-switching is thus used to enhance and support the representation of the characters. © 2009 Elsevier B.V. All rights reserved.

Calmfors L.,University of Stockholm | Wren-Lewis S.,University of Oxford
Economic Policy | Year: 2011

Fiscal watchdogs, so-called fiscal councils, have been proposed as a method to counter deficit bias of fiscal policy. The paper analyses theoretically what role fiscal councils could play and surveys empirically the activities of existing councils. Case studies of the Swedish Fiscal Policy Council and the UK Office for Budget Responsibility are done. It is concluded that fiscal councils should be advisory, rather than decision-making, and work as complements, rather than substitutes, to fiscal rules. Although no panacea, fiscal councils could play a useful role by at the same time strengthening fiscal discipline and allowing rules-based fiscal policy to be more flexible. A key issue is their political fragility and how their long-run viability should be secured. Three ways of guaranteeing their independence are suggested: (1) reputation-building; (2) formal national rules; and (3) international monitoring. - Lars Calmfors and Simon Wren-Lewis © CEPR, CES, MSH, 2011.

Gauffin K.,Karolinska Institutet | Vinnerljung B.,University of Stockholm | Hjern A.,Karolinska Institutet
International Journal of Epidemiology | Year: 2015

Background Alcohol misuse is an important global health determinant and a major contributor to health inequalities. We aimed to investigate the association between school performance and alcohol-related disorders in early adulthood in a longitudinal register-based national cohort study.Methods We followed a register-based national cohort of Swedish citizens born 1973-1984 (N = 948 440) from compulsory school graduation at age 15-16 to 2009. We divided the population into five groups: high school marks (> mean 1 SD); high average (between mean and mean 1 SD); low average (between mean and mean + 1 SD); low (< mean - 1SD); and missing. Cox proportional hazard models were used to investigate the relation between school marks at time of graduation and hospital care for alcohol-related disorders in early adulthood.Results There was a steep gradient in the risk of alcohol-related disorders related to school performance. In comparison with peers in the top category of school marks, students with low marks had adjusted hazard ratios of 8.02 [95% confidence interval (CI) 7.20 to 8.91], low average 3.02 (2.72 to 3.35) and high average 1.55 (1.39 to 1.73). The risk associated with low school marks was stronger in the male population and in the group from high socioeconomic background.Conclusions The study demonstrated a strong graded relation between low school performance and alcohol-related disorders in young adulthood. School performance should be taken into account when developing prevention programmes/policies targeting alcohol misuse among teenagers and young adults, especially if the aim is to reach high-risk groups. © The Author 2015. Published by Oxford University Press on behalf of the International Epidemiological Association.

Gustafsson N.-K.J.,University of Stockholm
European Addiction Research | Year: 2010

Background: In 2003, Denmark lowered its tax on spirits, and in 2004, Sweden increased its traveller import quotas. Aim: The aim of the study was to determine whether these two changes increased self-reported alcohol consumption in southern Sweden, which is located near Denmark. Method: Data were collected through telephone interviews with the general population between 2003 and 2006. Individuals aged 16-80 years were interviewed. Some lived in southern Sweden, others in the northern region, which was assumed to be unaffected by the policy changes and was thus used as a control site. Analyses were performed for the total population as well as by sex, age, socio-economic group and consumption pattern. Results: The expected results were not found: alcohol consumption in southern Sweden had not changed. The few statistically significant changes found in southern Sweden indicated decreases. In the north, however, consumption seemed to have increased. Conclusion: In addition to the two policy changes mentioned above, other changes seem to have affected alcohol consumption in Sweden. It is possible, however, that the policy changes have affected population groups not reached by the survey, and thus other types of data need to be analysed before drawing any far-reaching conclusions. © 2010 S. Karger AG, Basel.

Laun L.,Institute for Evaluation of Labour Market and Education Policy IFAU | Thoursie P.S.,University of Stockholm
Journal of Health Economics | Year: 2014

This paper analyses if privatisation of vocational rehabilitation can improve labour market opportunities for individuals on long-term sickness absence. We use a field experiment performed by the Public Employment Service and the Social Insurance Agency in Sweden during 2008-2010, in which over 4000 participants were randomly offered private and public rehabilitation. We find no differences in employment rates following rehabilitation between individuals who received rehabilitation by private and public providers. Also the average cost of rehabilitation was essentially equal for the two types of providers. This suggests that there are no large efficiency gains from privatising vocational rehabilitation. © 2013 Elsevier B.V.

In this paper we study the effects of field normalization baseline on relative performance of 20 natural science departments in terms of citation impact. Impact is studied under three baselines: journal, ISI/Thomson Reuters subject category, and Essential Science Indicators field. For the measurement of citation impact, the indicators item-oriented mean normalized citation rate and Top-5% are employed. The results, which we analyze with respect to stability, show that the choice of normalization baseline matters. We observe that normalization against publishing journal is particular. The rankings of the departments obtained when journal is used as baseline, irrespective of indicator, differ considerably from the rankings obtained when ISI/Thomson Reuters subject category or Essential Science Indicators field is used. Since no substantial differences are observed when the baselines Essential Science Indicators field and ISI/Thomson Reuters subject category are contrasted, one might suggest that people without access to subject category data can perform reasonable normalized citation impact studies by combining normalization against journal with normalization against Essential Science Indicators field. © 2010 Elsevier Ltd.

Tong L.,KTH Royal Institute of Technology | Duan L.,KTH Royal Institute of Technology | Xu Y.,Dalian University of Technology | Privalov T.,University of Stockholm | Sun L.,KTH Royal Institute of Technology
Angewandte Chemie - International Edition | Year: 2011

Small change, big difference: A minor structural modification of water-oxidation catalysts changes the kinetics of O2 evolution from second- to first-order (see scheme). According to DFT calculations, the torsional flexibility of the chelating ligands and their reorganization through the catalytic cycle are implicated in pathway selectivity, and the auxiliary carboxylate group becomes involved in proton-coupled nucleophilic attack. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kitsak M.,Boston University | Kitsak M.,University of California at San Diego | Gallos L.K.,City College of New York | Havlin S.,Bar - Ilan University | And 4 more authors.
Nature Physics | Year: 2010

Networks portray a multitude of interactions through which people meet, ideas are spread and infectious diseases propagate within a society 1-5. Identifying the most efficient 'spread-ers' in a network is an important step towards optimizing the use of available resources and ensuring the more efficient spread of information. Here we show that, in contrast to common belief, there are plausible circumstances where the best spreaders do not correspond to the most highly connected or the most central people 6-10. Instead, we find that the most efficient spreaders are those located within the core of the network as identified by the k-shell decomposition analysis11-13, and that when multiple spreaders are considered simultaneously the distance between them becomes the crucial parameter that determines the extent of the spreading. Furthermore, we show that infections persist in the high-k shells of the network in the case where recovered individuals do not develop immunity. Our analysis should provide a route for an optimal design of efficient dissemination strategies. © 2010 Macmillan Publishers Limited. All rights reserved.

Witt G.,University of Stockholm
International Journal of Remote Sensing | Year: 2011

The paper is devoted to optical remote-sensing techniques successfully applied to investigations of the mesospheric aerosol layer, starting with a short history of the development of optical sounding experiments. In the following part, a theoretical basis of scattering measurements is discussed. A brief description of the theoretical principles of optical analysis of aerosol properties, ending with a survey of current activity and, as yet, unresolved problems is presented. It can be concluded that there is a consensus regarding the size range of mesospheric aerosol particles. The contribution of the smallest particles cannot be assessed by current optical methods. The combination of the scattering measurement with an electromechanical impact detector is a promising technique. The true size distribution, more correctly a statistical average of many possible distributions, must rely on numerical modelling. Regarding the shape of the particles, the noctilucent-cloud particles are not perfect spheres. New insight into this problem can be expected from the ongoing observational program of the Atmospheric Chemistry Experiment (ACE) and Aeronomy of Ice in the Mesosphere (AIM). © 2011 Taylor & Francis.

Leimar O.,University of Stockholm | McNamara J.M.,University of Bristol
American Naturalist | Year: 2015

An organism's phenotype can be influenced by maternal cues and directly perceived environmental cues, as well as by its genotype at polymorphic loci, which can be interpreted as a genetic cue. In fluctuating environments, natural selection favors organisms that efficiently integrate different sources of information about the likely success of phenotypic alternatives. In such situations, it can be beneficial to pass on maternal cues that offspring can respond to. A maternal cue could be based on environmental cues directly perceived by the mother but also partly on cues that were passed on by the grandmother. We have used a mathematical model to investigate how the passing of maternal cues and the integration of different sources of information evolve in response to qualitatively different kinds of temporal and spatial environmental fluctuations. The model shows that the passing of maternal cues and the transgenerational integration of sources of information readily evolve. Factors such as the degree of temporal autocorrelation, the predictive accuracy of different environmental cues, and the level of gene flow strongly influence the expression of adaptive maternal cues and the relative weights given to different sources of information. We outline the main features of the relation between the characteristics of environmental fluctuations and the adaptive systems of phenotype determination and compare these predictions with empirical studies on cue integration. © 2015 by The University of Chicago.

Siegbahn P.E.M.,University of Stockholm
Journal of Photochemistry and Photobiology B: Biology | Year: 2011

In the present mini-review, computational work over the past decade on water oxidation in photosystem II (PSII) is summarized. The size of the chemical model used for the oxygen evolving complex (OEC) has during this time increased from the initial 20 atoms to the present day 220 atoms. The electronic structure methods used have during the same period only undergone minor improvements. It is concluded that the results have now reached a high level of convergence and the predictions for both the structure of the OEC and the O-O bond formation mechanism are most probably of higher accuracy than presently available from experiments. © 2011 Elsevier B.V. All rights reserved.

The Tibetan Plateau holds an ample record of past glaciations, and there is an extensive set of glacial deposits dated by exposure dating. Here a compilation is presented of 10Be exposure ages from 485 glacial deposits with 1855 individual samples on the Tibetan Plateau, and ELA depression estimates for the glacial deposits based on a simple toe to headwall ratio approach. To recalculate the Tibetan Plateau exposure ages, 10Be production rates from 24 calibration sites across the world are compiled and recalibrated yielding an updated global reference 10Be production rate. The recalculated exposure ages from the Tibetan Plateau glacial deposits are then divided into three groups based on exposure age clustering, to discriminate good (well-clustered) from poor (scattered) deglaciation ages. A major part of the glacial deposits have exposure ages affected by prior or incomplete exposure, complicating exposure age interpretations. The well-clustered deglaciation ages are primarily from mountain ranges along the margins of the Tibetan Plateau with a main peak between 10 and 30ka, indicating glacial advances during the global LGM. A large number of deglaciation ages older than 30ka indicates maximum glaciation predating the LGM, but the exposure age scatter generally prohibits accurate definition of the glacial chronology. The ELA depression estimates scatter significantly, but the main part is remarkably low. Average ELA depressions of 337±197m for the LGM and 494±280m for the pre-LGM indicate restricted glacier expansion. © 2014 Elsevier Ltd.

A cornerstone of democracy is the capacity of citizens to influence political decisions either through elections or by making their will known in the periods between elections. The aim of the present study is twofold: (1) to explore what factors inherent of the voluntary associations that determine the perceived success in their attempts to influence policy and (2) to investigate what role the composition of the local government have on the perceived success. This study is based on a survey conducted among 404 local voluntary associations in four different municipalities in Sweden. The results show that the frequency contacts influence perceived success positively, while the level of civic engagement of the voluntary associations affected the perceived success negatively. Having a heterogeneous local government also contributed positively to the perceived success to influence policy. © 2013 International Society for Third-Sector Research and The Johns Hopkins University.

Ackermann N.,National Autonomous University of Mexico | Szulkin A.,University of Stockholm
Archive for Rational Mechanics and Analysis | Year: 2013

For a domain Ω ⊂ ℝN we consider the equation -Δu + V(x)u = Qn(x){pipe}{u}{pipe}p-2u with zero Dirichlet boundary conditions and p ∈(2, 2*). Here V ≧ 0 and Qn are bounded functions that are positive in a region contained in Ω and negative outside, and such that the sets {Qn > 0} shrink to a point x0 ∈ Ω as n → ∞. We show that if un is a nontrivial solution corresponding to Qn, then the sequence (un) concentrates at x0 with respect to the H1 and certain Lq-norms. We also show that if the sets {Qn > 0} shrink to two points and un are ground state solutions, then they concentrate at one of these points. © 2012 Springer-Verlag Berlin Heidelberg.

Radke M.,University of Stockholm | Radke M.,Helmholtz Center for Environmental Research | Maier M.P.,University of Bayreuth
Water Research | Year: 2014

Previous studies revealed large differences in the transformation of pharmaceuticals in rivers with similar characteristics. The present work aimed at answering the question whether these differences are related to the transformation capacity of the specific river sediments. More generally, we also aimed at evaluating the overall diagnostic power of water/sediment tests. Incubation experiments with 9 pharmaceuticals were carried out with sediments sampled from three rivers. All compounds expect carbamazepine were removed at dissipation half-lives between 2.5 and 56days; biotransformation was identified as the major removal process. Interestingly, sediment from river Roter Main was more efficient in removing pharmaceuticals than sediment from river Gründlach, while the opposite pattern was observed in previous field studies. Obviously, the physical boundary conditions are governing the actual elimination of pharmaceuticals and not the transformation potential of the specific sediments. In a separate experiment, an immediate onset of transformation was observed after introducing oxygen to an anoxic water/sediment system. Transformation rates in sediments sampled from several sites within one river varied up to a factor of 2.5. This considerable in-stream variability is a critical factor for environmental risk assessment where single cutoff values are being used for evaluating a compound's persistence. © 2014 Elsevier Ltd.

Molander S.,University of Stockholm
Research in Consumer Behavior | Year: 2011

Purpose: To develop CCT's practice perspective to increase the understanding of the consumption context and thereby of the sociohistoric patterning of consumption. Design/methodology/approach: An ethnographic exploration of how the different practices involved in a consumption situation, like the everyday dinner among single mothers, contextualized consumption. Findings: The chapter concludes that mothering, defined as a metapractice, dominated the consumption situation and organized the other practices involved. Originality/value: Introducing the concept of meta-practices having a major influence over our consumption and thus a type of practice consumption research should look for. Copyright © 2011 by Emerald Group Publishing Limited.

Alexandersson P.,University of Stockholm
Electronic Journal of Combinatorics | Year: 2012

We prove that for arbitrary partitions, and integers 0 ≤ c < r ≤ n, the sequence of Schur polynomials for k sufficiently large, satisfy a linear recurrence. The roots of the characteristic equation are given explicitly. These recurrences are also valid for certain sequences of minors of banded Toeplitz matrices. In addition, we show that Widom's determinant formula from 1958 is a special case of a well-known identity for Schur polynomials.

A framework is constructed for how to relate ecosystem services to environmental justice. The benefits humans and society can derive from biophysical processes cannot be viewed as objectively existing " out there" , but as entangled in social and political processes. This is unpacked through the analytical moments of generation, distribution and articulation of ecosystem services. Social practice moderates the generation of benefits from biophysical processes (through urban development patterns and day-to-day management of urban ecosystems), but also who in society that benefits from them, i.e. the distribution of ecosystem services (viewed here as the temporal and spatial scales at which it is possible for humans to benefit from biophysical processes). Moreover, for biophysical processes to attain value in decision-making, a social practice of value articulation is needed. The framework then moves between two levels of analysis. At the city-wide level, an ecological network translates how urban 'green' areas, viewed as nodes, are interconnected by ecological flows (water, species movement, etc.) where nodes have different protective and management capacities. The network captures spatial complexity-what happens in one location, can have effects elsewhere. At the local level, urban struggles over land-use are studied to trace how actors utilize artifacts and social arenas to articulate how certain biophysical processes are of value. Competing networks of value articulation strive to influence land-use, and multiple local studies bring understanding of how power operates locally, informing city-wide analyses. Empirical studies from Stockholm, Cape Town and other cities inform the framework. © 2012 Elsevier B.V.

Tedre M.,University of Stockholm
SIGCSE 2013 - Proceedings of the 44th ACM Technical Symposium on Computer Science Education | Year: 2013

All major computing curricula recommendations mention methodological skills and knowledge as an important learning objective in undergraduate and graduate education. None of those curricula recommendations, however, include a methodology course for students. One reason for that lack might be the stunning diversity of computing fields and the unique methods each branch of computing uses in their research. A methodology course in computing has to make a choice between three options: a narrow but deep specialization in some techniques and methods, a broad but superficial covering of a large number of methods, and a higher-level view on the principles of methodology and research design. This paper adopts the high-level approach, and presents a course description for a methodology course that aims at providing students understanding of how the elements of a research study link together. Copyright © 2013 ACM.

Bergstrom J.,University of Stockholm | Faber C.,KTH Royal Institute of Technology | van der Geer G.,University of Amsterdam
Selecta Mathematica, New Series | Year: 2014

We give an explicit conjectural formula for the motivic Euler characteristic of an arbitrary symplectic local system on the moduli space A3 of principally polarized abelian threefolds. The main term of the formula is a conjectural motive of Siegel modular forms of a certain type; the remaining terms admit a surprisingly simple description in terms of the motivic Euler characteristics for lower genera. The conjecture is based on extensive counts of curves of genus three and abelian threefolds over finite fields. It provides a lot of new information about vector-valued Siegel modular forms of degree three, such as dimension formulas and traces of Hecke operators. We also use it to predict several lifts from genus 1 to genus 3, as well as lifts from G2 and new congruences of Harder type. © 2013 Springer Basel.

Rudbeck M.,University of Stockholm
International Journal of Quantum Chemistry | Year: 2012

The addition of extravalence, polarization and diffuse functions, were studied in order to conclude how they affect the PO stretching frequencies of several biological relevant phosphate molecules. The results show that the polarization and the diffuse functions have opposite effects on the frequencies: the polarization functions downshift while the diffuse functions upshift the frequencies. The effect of the valence functions was more difficult to interpret. The effect of the conductor-like screening model (CPCM)-continuum model was also studied. The results show that the CPCM-continuum model has a substantial effect on the frequencies for these small molecules. The continuum model's efficiency is mainly due to its effect on the geometries and not on the frequencies. © 2011 Wiley Periodicals, Inc.

Parment A.,University of Stockholm
Journal of Retailing and Consumer Services | Year: 2013

This paper presents some significant empirical findings about generational cohorts and their shopping behavior. Marketing has long relied on the use of market segmentation. While birth age has been a useful way to create groups, it describes segments but does not help to understand segment motivations. However, environmental events experienced during one's coming of age create values that remain relatively unchanged throughout one's life. Such values provide a common bond for those in that age group, or generational cohort. Segmenting by 'coming of age' age provides a richer segmentation approach than birth age. This study compares two significant cohorts: Baby Boomers and Generation Y, with respect to their shopping behavior and purchase involvement for food, clothing and automobiles. For the three types of products, Baby Boomers value the retail experience and in-store service higher than Generation Y. For Baby Boomers, the purchase process starts with a retailer the consumer trusts, who gives advice for choosing the right product, while for Generation Y, the purchase process starts with choosing a product. This study presents implications for retail strategies that have an appeal to different generational cohorts and considers how retailers should deal with building customer relationships. © 2012 Elsevier Ltd.

Skageby J.,University of Stockholm
Library Hi Tech | Year: 2012

Purpose: This paper seeks to propose that the current social media surge gives rise to what can be called social information behaviour. Social information behaviour is characterised, at least partly, by a tension between serendipity and disruption. While serendipity is a promoted feature of social media and social information behaviour, social disruption can be seen as its ironic counterpart. This paper goes on to explore different kinds of social disruption that emerge with the use of social media services. Design/methodology/approach: The paper uses a meta-ethnographical approach and draws on results from three online ethnographic studies. User activities are conceptualised as social information behaviour and focus is put on potential social disruption. Findings: The paper discusses five prevalent tensions relating to social disruption: market logic and social logic; public and private; work and non-work; individual and collective; and IRL (In Real Life) or AFK (Away From Keyboard). Research limitations/implications: The paper mainly focuses on the disruptive side of social information behaviour. Future work would include studies and comparisons of serendipitous effects. Practical implications: The findings are relevant for library and information science academics, analysts and professionals interested in social information behaviour as it emerges over new social mediating technologies. Originality/value: This paper proposes the notion of social information behaviour and provides a conceptual analytical pair in serendipity and social disruption. Theoretical discussion is conducted with reference to "ironic technics". The paper compiles and highlights prevalent social disruptions from previous online ethnographical studies on social media usage. © Emerald Group Publishing Limited.

The aim of this article is to discuss and use Marx's theory on primitive accumulation, outlined in the first volume of Capital, in relation to media and communication research. In order to develop Marx's argument the discussion is revitalized through Harvey's concept of accumulation by dispossession. The article focuses on two different fields within media and communication research where the concept of accumulation by dispossession is applicable. First, the role of news media content, news flows and news media systems are discussed in relation to social mobilization against capitalism, privatizations, and the financial sector. Second, Marx's theory is used to examine how communication in Web 2.0 and the development of ICTs could advance the processes of capital accumulation by appropriating the work performed by users of Web 2.0 and by increasing the corporate surveillance of Internet users. In conclusion, by analyzing how primitive accumulation is intertwined with contemporary expanded reproduction of capital, the article shows that Marx's theory can contribute to critical media and communication research in several ways.

Backstrom A.,University of Stockholm
Sport, Education and Society | Year: 2014

The body has become a vital research object in several disciplines in recent years. Indeed, in the social sciences and humanities, a corporeal turn in which embodiment has become a key concept related to learning and socialisation is discussed. This cross-disciplinary paper addresses the epistemological question of how we know what we know and theoretically and empirically contributes to current arguments of a shift from embodiment to emplacement. In other words, this study strives for understanding of the intersection of mind, body and place through a focus on how bodily knowing is formed as part of a moving world. The purpose of the paper is to explore the kinaesthetic experience as bodily knowing in emplaced semi-formal teaching. Through long-term ethnography in a Swedish skateboard setting and in-depth analysis of digital visual material, this paper demonstrates how kinaesthetic experience might be viewed as knowing and how a particular type of this experience might be interpreted as explosiveness and, as such, an act of physical remembrance and energy transformation. Knowing is formed along paths of movement and rhythm, and kinaesthesia is identified as a multisensory experience. It is argued that a fruitful way of bridging the mind-body divide is to view the body as un/knowing, rendering it both knowing and not knowing simultaneously. Moreover, emplaced via its senses in a sociocultural and spatio-temporal environment, this conceptualisation of a moving body in a moving world might allow for re-thinking regarding how a body in context knows, teaches and, possibly, learns. © 2012 © 2012 Taylor & Francis.

Jahnke A.,University of Stockholm | Mayer P.,University of Aarhus
Journal of Chromatography A | Year: 2010

The partitioning of non-polar analytes into the silicone polydimethylsiloxane (PDMS) is the basis for many analytical approaches such as solid phase microextraction (SPME), stir bar sorptive extraction (SBSE) and environmental passive sampling. Recently, the methods have been applied to increasingly complex sample matrices. The present work investigated the possible effect of complex matrices on the sorptive properties of PDMS. First, SPME fibers with a 30. μm PDMS coating were immersed in 15 different matrices, including sediment, suspensions of soil and humic substances, mayonnaise, meat, fish, olive oil and fish oil. Second, the surface of the fibers was wiped clean, and together with matrix-free control fibers, they were exposed via headspace to 7 non-polar halogenated organic chemicals in spiked olive oil. The fibers were then solvent-extracted, analyzed, and the ratios of the mean concentrations in the matrix-immersed fibers to the control fibers were determined for all matrices. These ratios ranged from 92% to 112% for the four analytes with the highest analytical precision (i.e. polychlorinated biphenyls (PCBs) 3, 28, 52 and brominated diphenyl ether (BDE) 3), and they ranged from 74% to 133% for the other three compounds (i.e. PCBs 101, 105 and γ-hexachlorocyclohexane (HCH)). We conclude that, for non-polar, hydrophobic chemicals, the sorptive properties of the PDMS were not modified by the diverse investigated media and consequently that PDMS is suited for sampling of these analytes even in highly complex matrices. © 2010 Elsevier B.V.

Nyberg G.,University of Stockholm
European Physical Education Review | Year: 2014

The aim of this paper is to explore and develop ways to describe what there is to know, from the perspective of the one who knows, when knowing how to carry out a complex movement. The paper will challenge the distinction between mental and physical skills, drawing on theories of tacit knowing (Polanyi, 1969), knowing how (Ryle, 1949) and knowing-in-action (Schön, 1991), together with empirical data from the context of elite sport. One assumption is that exploring knowing in movement, in this context, can contribute to developing students' movement education in physical education (PE). Pole-vaulting provides examples of what there is to know, in terms of embodied capabilities possible to explicate and develop as an educational objective in PE, irrespective of the context of competitive sports. Explicating the knowing (or capabilities) involved in the "capability to move," as exemplified in this study, could emphasize an educational aim concerning practical knowledge, such as knowing in movement, and not necessarily specific skills related to competitive sport activities. © The Author(s) 2013.

Gruner D.,University of Stockholm
The International journal of oral & maxillofacial implants | Year: 2011

The objective of this study was to assess the use of ion beam polishing for preparing cross sections suitable for high-resolution scanning electron microscope (SEM) investigation of dental implants with a brittle porous oxide layer and of bone/implant interfaces. Thirteen Nobel Biocare TiUnite implants were placed in minipigs. After 4 weeks, the implant and surrounding bone were removed en bloc and the implant was cut axially into two halves. The cross section was then polished with an argon ion beam. Additionally, ion beam-polished cross sections were prepared from four as-received implants. Ion beam-polished surfaces were studied with a field emission SEM (FE-SEM). With FE-SEM, up to 1 mm along the interface of ion beam-polished implant surfaces can be studied with a resolution of a few nanometers. Filled and unfilled pores of the porous TiUnite coating can be distinguished, providing information on pore accessibility. Implant-bone interfaces can be analyzed using backscattered electron images, where titanium, the oxide layer, mineralized extracellular matrix, and osteocyte lacunae/resin/soft tissue can easily be distinguished as a result of atomic number contrast and the sharp boundaries between the different materials. Filled and unfilled pores can be distinguished. Characterization of local chemistry is possible with energy dispersive X-ray spectrometry, and bone growth into small pores (< 1 μm) can be unambiguously confirmed. Conclusion: FE-SEM complements the established methods for the characterization of interfaces and bridges the wide gap in accessible length scale and resolution between the observations of mechanically polished interfaces by optical or scanning electron microscopes and the observation of focused ion beam-milled sections in a transmission electron microscope.

This article repositions sovereignty on the basis of a study of recent regulatory approaches to organized crime and money laundering. The spread of techniques across administrative domains is traced through organizational documents and interviews with practitioners, and related to an observed trend toward integration between policing research and regulation research. The same trend, however, assigns sovereignty to the periphery. A richer notion of sovereignty is recovered through a reading of the classical theorists, and used to tease out the articulation of sovereignty in current state strategies. Theorizing ‘sovereignty at the center’ as opposed to ‘sovereignty at the periphery’ challenges basic assumptions about the relationship between the state and economic activity, and in particular about the utility-oriented character of state violence. © The Author(s) 2014.

Hogbom M.,University of Stockholm
Journal of Biological Inorganic Chemistry | Year: 2010

The manganese/iron-carboxylate proteins make up a recently discovered group of proteins that contain a heterodinuclear Mn/Fe redox cofactor. The chemical potential of the heterodinuclear metal site is just starting to be characterized, but available data suggest that it may have capabilities for similarly versatile chemistry as the extensively studied diiron-carboxylate cofactor. The presently identified members of the manganese/iron-carboxylate proteins are all sequence homologues of the radical-generating R2 subunit of class I ribonucleotide reductase, canonically a diiron protein. They are also commonly misannotated as such in databases. In spite of the sequence similarity, the manganese/iron-carboxylate proteins form at least two functionally distinct groups, radical-generating ribonucleotide reductase subunits and ligand-binding Mn/Fe proteins. Here, the presently available sequences for the manganese/iron-carboxylate proteins are gathered, grouped, and analyzed. The analysis provides sequence determinants that allow group identification of new sequences on the single-protein level. Key differences between the groups are mapped on the known representative structures, providing clues to the structural prerequisites for metal specificity, cofactor formation, and difference in function. The organisms that encode manganese/iron-carboxylate proteins are briefly discussed; their environmental preference suggests that the Mn/Fe heterodinuclear cofactor is preferred by extremophiles and pathogens with a particularly high relative presence in Archaea. © 2009 SBIC.

Kodandaramaiah U.,University of Stockholm | Kodandaramaiah U.,University of Cambridge
Behavioral Ecology | Year: 2011

Numerous butterflies have circular patterns called eyespots on their wings. Explanations for their functional value have until recently remained hypothetical. However, several studies in the last few years have supported long-standing hypotheses, and the current paper reviews these recent advances. Large and conspicuous eyespots are thought to be effective by being intimidating to predators and thus reducing predation. This hypothesis has received strong support in different studies. It has been shown that eyespots are intimidating because of their conspicuousness, but experimental support for the idea that eyespots are effective by mimicking vertebrate eyes is at the moment lacking. Studies have also tested the deflection hypothesis, where smaller marginal eyespots are thought to deflect attacks away from the body of the prey, increasing chances of survival with a torn wing. Despite previous negative results, recent work has shown that eyespots can indeed deflect attacks toward themselves under specific conditions. Furthermore, data show that dorsal eyespots are used by males and females as signals during courtship. How the diversity in ventral eyespot patterning has evolved remains a mystery. Future directions and further challenges in understanding the adaptive value of eyespots are discussed. © 2011 The Author. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved.

Magnusdottir B.T.,University of Stockholm
Biometrical Journal | Year: 2016

The aim of dose finding studies is sometimes to estimate parameters in a fitted model. The precision of the parameter estimates should be as high as possible. This can be obtained by increasing the number of subjects in the study, N, choosing a good and efficient estimation approach, and by designing the dose finding study in an optimal way. Increasing the number of subjects is not always feasible because of increasing cost, time limitations, etc. In this paper, we assume fixed N and consider estimation approaches and study designs for multiresponse dose finding studies. We work with diabetes dose-response data and compare a system estimation approach that fits a multiresponse Emax model to the data to equation-by-equation estimation that fits uniresponse Emax models to the data. We then derive some optimal designs for estimating the parameters in the multi- and uniresponse Emax model and study the efficiency of these designs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kleman J.,University of Stockholm | Applegate P.J.,Pennsylvania State University
Quaternary Science Reviews | Year: 2014

Continued atmospheric and ocean warming places parts of the West Antarctic Ice Sheet at risk for collapse through accelerated ice flow and grounding line retreat over reversed bed slopes. However, understanding of the speed and duration of ice sheet instability events remains incomplete, limiting our ability to include these events in sea level rise projections. Here, we use a first-order, empirical approach, exploring past instability events in the Fennoscandian (FIS) and Laurentide (LIS) ice sheets to establish a relationship between catchment size and the duration of instability events. We also examine how instabilities propagate through ice sheet catchments, and how this propagation is controlled by topography and existing flow organisation at the onset of an event. We find that the fastest documented paleo-collapses involved streaming or surging in corridors that are wide compared to their length, and in which fast flow did not resume after the event. Distributed ice stream networks, in which narrow ice streams were intertwined with slow-flow interstream ridges, are not represented among the fastest documented events. For the FIS and LIS, there is geological evidence for instability events covering areas of ~100,000km2, with durations between 100 and 300yr. Comparison of the spatial patterns and topographic contexts of Lateglacial collapse events in former Northern Hemisphere ice sheets and the current WAIS suggest that only a minor part of the WAIS area may be at risk for unimpeded collapse, and that negative feedbacks will likely slow or halt ice drawdown in remaining areas. The Pine Island Glacier (PIG) and Thwaites Glacier (TG) catchments in West Antarctica are likely to respond in very different ways to possible further grounding line retreat. The PIG may experience a minor collapse over its main trunk, but the bed topography favours a less dramatic retreat thereafter. The TG is probably not as close to a threshold as PIG, but once efficient drainage has progressed inwards to reach the Bentley Subglacial Basin (BSB) and Bentley Subglacial Trench (BST), a full collapse of the area may occur. The likely time perspective for a BSB-BST collapse is the time required for 100-200km of grounding line retreat in the TG systemplus100-300 years for an actual collapse event. © 2013 The Authors.

Friedman K.,British Petroleum | Eriksson H.,University of Stockholm | Tardy E.,British Petroleum | Pakoa K.,British Petroleum
Fish and Fisheries | Year: 2011

Identifying rates of change in the abundance of sea cucumbers under differing management regimes is fundamental to estimating commercial yields, identifying ecological interactions and facilitating management. Here, we review the status of sea cucumber stocks from a range of Pacific Island countries (Samoa, Tonga, Palau, Fiji and Papua New Guinea), some of which have had a moratorium on exports for up to a decade. We use a time-series approach to look at variation in sea cucumber presence, coverage and density from survey and re-survey data. Results give an appreciation of variation between 'high' status (less impacted) and depleted stocks. Survey data show marked declines in coverage and abundance as a result of artisanal fishing activity, and although species groups were not lost at a country level, local extirpation and range restriction was noted. Resilience and 'recovery' following cessation of fishing varied greatly, both among locations and among the species targeted. Worryingly, even after extended periods of moratorium, the density of some species was markedly low. In many cases, the densities were too low for commercial fishing, and may be at a level where the effective population size is constrained due to 'Allee' affects. From these results, we suggest that management regimes presently employed are generally not well aligned with the level of response to fishing mortality that can be expected from sea cucumber stocks. New adaptive, precautionary approaches to management are suggested, which would allow more timely interventions to be made, while refined information on stock dynamics is sought. © 2010 Blackwell Publishing Ltd.

Albertazzi L.,TU Eindhoven | Van Der Zwaag D.,TU Eindhoven | Leenders C.M.A.,TU Eindhoven | Fitzner R.,TU Eindhoven | And 3 more authors.
Science | Year: 2014

Supramolecular fibers are prominent structures in biology and chemistry. A quantitative understanding of molecular exchange pathways in these one-dimensional aggregates was obtained by a combination of super-resolution stochastic optical reconstruction microscopy and stochastic simulation. The potential of this methodology is demonstrated with a set of well-defined synthetic building blocks that self-assemble into supramolecular fibrils. Previous ensemble measurements hid all molecular phenomena underpinning monomer exchange, but the molecular pathway determined from single-aggregate studies revealed unexpected homogeneous exchange along the polymer backbone. These results pave the way for experimental investigation of the structure and exchange pathways of synthetic and natural supramolecular fibers.

The origins of interactions between angiosperms and fruit-eating seed dispersers have attracted much attention following a seminal paper on this topic by Tiffney (1984). This review synthesizes evidence pertaining to key events during the evolution of angiosperm-frugivore interactions and suggests some implications of this evidence for interpretations of angiosperm-frugivore coevolution. The most important conclusions are: (i) the diversification of angiosperm seed size and fleshy fruits commenced around 80million years ago (Mya). The diversity of seed sizes, fruit sizes and fruit types peaked in the Eocene around 55 to 50Mya. During this first phase of the interaction, angiosperms and animals evolving frugivory expanded into niche space not previously utilized by these groups, as frugivores and previously not existing fruit traits appeared. From the Eocene until the present, angiosperm-frugivore interactions have occurred within a broad frame of existing niche space, as defined by fruit traits and frugivory, motivating a separation of the angiosperm-frugivore interactions into two phases, before and after the peak in the early Eocene. (ii) The extinct multituberculates were probably the most important frugivores during the early radiation phase of angiosperm seeds and fleshy fruits. Primates and rodents are likely to have been important in the latter part of this first phase. (iii) Flying frugivores, birds and bats, evolved during the second phase, mainly during the Oligocene and Miocene, thus exploiting an existing diversity of fleshy fruits. (iv) A drastic climate shift around the Eocene-Oligocene boundary (around 34 Mya) resulted in more semi-open woodland vegetation, creating patchily occurring food resources for frugivores. This promoted evolution of a 'flying frugivore niche' exploited by birds and bats. In particular, passerines became a dominant frugivore group worldwide. (v) Fleshy fruits evolved at numerous occasions in many angiosperm families, and many of the originations of fleshy fruits occurred well after the peak in the early Eocene. (vi) During periods associated with environmental change altering coevolutionary networks and opening of niche space, reciprocal coevolution may result in strong directional selection formative for both fruit and frugivore evolution. Further evidence is needed to test this hypothesis. Based on the abundance of plant lineages with various forms of fleshy fruits, and the diversity of frugivores, it is suggested that periods of rapid coevolution in angiosperms and frugivores occurred numerous times during the 80million years of angiosperm-frugivore evolution. © 2016 Cambridge Philosophical Society.

Second-homes are vital parts of the encountering of the rural in the Western World. The way they are perceived in society is important to explore as it can influence how and by whom this part of the rural is used. This paper explores the media construction of a specific type of second-homes in Sweden; cottages that since the 1950s have transformed from poor smallholdings to beloved second-homes. Besides being lived spaces, these cottages have become well known features of rural Sweden, symbols of national identity and described by media as rural idylls. They can be seen as having a cultural centrality in the revaluation of rurality and the shift towards post-productivist countryside in Sweden. But how could this type of humble cottage become so significant and what does the image of it really imply? This is studied through a discourse analysis of the representation of these cottages in a monthly home magazine from 1956 to 2008 with a particular interest in the production and naturalisation of them as important rural artefacts and national symbols. The paper discusses how material and immaterial dimensions have interacted in this construction process as well as possible social implications of the representations. Conclusively, the representations construct a restricted image of cottages and their users and of why cottages are important and should be taken care of. These representations are building on values, ideas and norms embedded in a highlighted and particular materiality which makes these seem innocent, natural and common sense. By exploring this the paper contributes to the wider inquiry into the discursive construction of the rural where seemingly innocent and natural ways of representing places, people and artefacts can produce strong and excluding norms and values regarding the rural and its users and uses. © 2014 Elsevier Ltd.

Talavera G.,University Pompeu Fabra | Dinca V.,University Pompeu Fabra | Dinca V.,University of Stockholm | Vila R.,University Pompeu Fabra
Methods in Ecology and Evolution | Year: 2013

Summary: The generalized mixed Yule-coalescent (GMYC) model has become one of the most popular approaches for species delimitation based on single-locus data, and it is widely used in biodiversity assessments and phylogenetic community ecology. We here examine an array of factors affecting GMYC resolution (tree reconstruction method, taxon sampling coverage/taxon richness and geographic sampling intensity/geographic scale). We test GMYC performance based on empirical data (DNA barcoding of the Romanian butterflies) on a solid taxonomic framework (i.e. all species are thought to be described and can be determined with independent sources of evidence). The data set is comprehensive (176 species), and intensely and homogeneously sampled (1303 samples representing the main populations of butterflies in this country). Taxonomy was assessed based on morphology, including linear and geometric morphometry when needed. The number of GMYC entities obtained constantly exceeds the total number of morphospecies in the data set. We show that c. 80% of the species studied are recognized as entities by GMYC. Interestingly, we show that this percentage is practically the maximum that a single-threshold method can provide for this data set. Thus, the c. 20% of failures are attributable to intrinsic properties of the COI polymorphism: overlap in inter- and intraspecific divergences and non-monophyly of the species likely because of introgression or lack of independent lineage sorting. Our results demonstrate that this method is remarkably stable under a wide array of circumstances, including most phylogenetic reconstruction methods, high singleton presence (up to 95%), taxon richness (above five species) and the presence of gaps in intraspecific sampling coverage (removal of intermediate haplotypes). Hence, the method is useful to designate an optimal divergence threshold in an objective manner and to pinpoint potential cryptic species that are worth being studied in detail. However, the existence of a substantial percentage of species wrongly delimited indicates that GMYC cannot be used as sufficient evidence for evaluating the specific status of particular cases without additional data. Finally, we provide a set of guidelines to maximize efficiency in GMYC analyses and discuss the range of studies that can take advantage of the method. © 2013 British Ecological Society.

Hillebrand H.,Carl von Ossietzky University | Soininen J.,University of Helsinki | Snoeijs P.,University of Stockholm
Global Change Biology | Year: 2010

The responses of ecological communities and ecosystems to increased rates of environmental change will be strongly influenced by variation in the diversity of community composition. Yet, our understanding of how diversity is affected by rising temperatures is inconclusive and mainly based on indirect evidence or short-term experiments. In our study, we analyse the diversity and species turnover of benthic epilithic communities within the thermal flume of a nuclear power plant at the Swedish coast. This flume covers the range of predicted future temperature rises. Species composition was significantly different between control sites and sites with higher temperatures. We found that temperature had little effect on the number of species in three functional groups (macroinvertebrates, benthic diatoms, and macrophytes, which here comprise multicellular algae and macroscopic colonies of unicellular algae and cyanobacteria), neither at single sampling dates nor summed for the entire observation year. However, species turnover significantly increased with increasing temperature for diatoms, macrophytes and invertebrates. Different temperature regimes resulted in significantly different species composition and indicator species. Thus, increasing temperatures in the thermal flume increased temporal beta-diversity and decreased compositional stability of communities, although observed richness did not change at any point in time. We highlight the need to investigate the consequences of such declines in compositional stability for functional stability of ecosystem processes. © 2009 Blackwell Publishing Ltd.

Ledberg A.,University of Stockholm
Drug and Alcohol Dependence | Year: 2015

Highlights: Background: In recent years the recreational use of new psychoactive substances (NPS) has increased. NPS are considered a threat to public health and the main response to this threat is to make the selling and buying of these substances illegal. In Sweden, during the last 5 years, 62 new substances have been classified as narcotics but little is known of the effects of making a particular substance illegal. The aim of this work is to study how legal status influences the interest in NPS in Sweden. Methods: Forty-five thousand posts made in a Swedish Internet discussion forum (Flashback Forum) related to eight NPS (MDPV, Methylone, 4-MEC, 4-HO-MET, MXE, 6-APB, AH-7921, and 3-MMC) were used to derive time-dependent measures of interest in these substances. Intervention analyses were used to investigate the effects of legal status on the forum interest. Results: For all eight substances the activity on the forum (measured as number of posts per day) showed a drastic decrease around the time of classification. The statistical analysis showed that in seven of eight cases, the drop in activity could be accounted for by the legal status of the substances. Conclusions: The legal status of the substances was shown to have a substantial effect on the interest in the substances. The novel measure used to trace the interest in particular NPS could be a useful tool to follow trends in substance use in almost real-time. © 2015 Elsevier Ireland Ltd.

Siegbahn P.E.M.,University of Stockholm
Journal of the American Chemical Society | Year: 2013

Detailed mechanisms for substrate water exchange in the oxygen evolving complex in photosystem II have been determined with DFT methods for large models. Existing interpretations of the experimental water exchange results have been quite different. By many groups, these results have been the main argument against the water oxidation mechanism suggested by DFT, in which the oxygen molecule is formed between a bridging oxo and an oxyl radical ligand in the center of the OEC. That mechanism is otherwise in line with most experiments. The problem has been that the mechanism requires a rather fast exchange of a bridging oxo ligand, which is not a common finding for smaller Mn-containing model systems. However, other groups have actually favored a substrate derived oxo ligand partly based on the same experiments. In the present study, three S-states have been studied, and the rates have been well reproduced by the calculations. The surprising experimental finding that water exchange in S 1 is slower than the one in S2 is reproduced and explained. The key to this rate difference is the ease by which one of the manganese centers (Mn3) is reduced. This reduction has to occur to release the substrate water from Mn3. The similar rate of the slow exchange in S2 and S3 has been rationalized on the basis of earlier experiments combined with the present calculations. The results strongly support the previous DFT-suggested water oxidation mechanism. © 2013 American Chemical Society.

Karlsson B.,University of Stockholm
International Journal of Biometeorology | Year: 2014

Butterflies are like all insects in that they are temperature sensitive and a changing climate with higher temperatures might effect their phenology. Several studies have found support for earlier flight dates among the investigated species. A comparative study with data from a citizen science project, including 66 species of butterflies in Sweden, was undertaken, and the result confirms that most butterfly species now fly earlier during the season. This is especially evident for butterflies overwintering as adults or as pupae. However, the advancement in phenology is correlated with flight date, and some late season species show no advancement or have even postponed their flight dates and are now flying later in the season. The results also showed that latitude had a strong effect on the adult flight date, and most of the investigated species showed significantly later flights towards the north. Only some late flying species showed an opposite trend, flying earlier in the north. A majority of the investigated species in this study showed a general response to temperature and advanced their flight dates with warmer temperatures (on average they advanced their flight dates by 3.8 days/°C), although not all species showed this response. In essence, a climate with earlier springs and longer growing seasons seems not to change the appearance patterns in a one-way direction. We now see butterflies on the wings both earlier and later in the season and some consequences of these patterns are discussed. So far, studies have concentrated mostly on early season butterfly-plant interactions but also late season studies are needed for a better understanding of long-term population consequences. © 2013 ISB.

Sano H.,University of Stockholm
Plant Signaling and Behavior | Year: 2010

Since Lamarck proposed the idea of inheritance of acquired traits 200 years ago, much has been said for and against it, but the theory was finally declined after the 1930s. Despite of the negative opinions of the majority of geneticists, botanists and plant breeders have long recognized that altered properties during the growth were occasionally transmitted to the offspring. This was also the case with artificially altered properties such as dwarfism, flowering timing and plant stature, which were induced by a non-mutagenic chemical, 5-azacytidine and its derivatives. As these drugs are powerful inhibitors of DNA methylation in vivo, a close correlation between methylation and phenotypic expression was suggested. Subsequent studies showed that rice plants acquired disease resistance upon demethylation of the corresponding resistant gene, and that both resistant trait and hypomethylated status were inherited by the progeny up to 9 generations. Whether or not the methylation pattern changes under natural condition was then questioned, and recent studies have indicated that it indeed naturally changes in response to environmental stresses. Whether or not the altered methylation pattern during the vegetative growth is heritable was also questioned, and studies on toadflax and rice affirmed the question, showing stable maintenance of hypermethylation in the former and hypomethylation in the latter for 250 and 10 years, respectively. The observation strongly suggested that acquired traits can be heritable as far as the acquired methylation pattern is stably transmitted. This concept is consistent with the Lamarck's theory of the inheritance of acquired traits, which therefore should be carefully reevaluated to reestablish his impaired reputation. © 2010 Landes Bioscience.

Shishova M.,Saint Petersburg State University | Lindberg S.,University of Stockholm
Journal of Plant Physiology | Year: 2010

An important question in modern plant biology concerns the mechanisms of auxin perception. Despite the recently discovered soluble receptor, the F-box protein TIR1, there is no doubt that another type of signal perception exists, and is linked to the plasma membrane. Two models for the receptor have been suggested: either the receptor includes a protein kinase, or it is coupled with a G-protein. We propose a third model, acting through Ca2+-channels in the plasma membrane. The model is based on the revealed rapid auxin-induced reactions, including changes in the membrane potential, shifts in cytosol concentration of Ca2+ and H+ and modulation of cell sensitivity to hormones by the external Ca2+ concentration. Detailed inhibitor analysis with both living cells and isolated plasma membranes show that auxin might directly stimulate Ca2+ transport through the plasma membrane. A hypothetical scheme of auxin perception at the plasma membrane is suggested together with further transduction events. In addition, comparative analyses of auxin and serotonin perceptions are provided. © 2010 Elsevier GmbH. All rights reserved.

Velasquez Atehortua J.,University of Stockholm
Antipode | Year: 2014

Outright victories against urban elitisation are rare in the current urban revolution. This article highlights how urban elitisation is confronted in Chacao, the most elite and urban part of Venezuela. Initially it reviews how this urban elitisation created the main economic, political and military strongholds of the opposition to the Bolivarian revolution. Then, in contesting it, the urban and Bolivarian revolutions feed each other through women's participation in invited and invented spaces of citizenship. From such spaces, Chacao women in their settler's movement organised struggles of insurgent citizenship to stop elitist urban renewal agendas and develop further forms of insurgent urbanism to conduct an urban renewal from below and establish a New Socialist Community for 600 families. They emerged as a revolutionary class to implement Bolivarian policies addressing the inefficiency and opportunism of the bureaucratic state and contesting urban elitisation with an anti-capitalist and anti-imperialist insurgent urbanism. © 2013 Antipode Foundation Ltd.

This study tests the hypothesis that a disjuncture between an individual's attained level of education and that held by average workers in the individual's occupation leads to higher mortality among those with a prolonged mismatched status. Swedish register data are used in a 19-year longitudinal mortality follow-up study of all causes and specific causes of mortality. Participants were all men and women born between 1926 and 1985 who were alive on 1 September 1990, who had concurrent information on their attained level of education and the specific occupation or industry they were employed in during this period for at least a consecutive year. An objective measure of educational and occupational mismatch was constructed from these data. Those with a stable, over-educated matched, or under-educated employment status are included in the final analysis (N = 2,482,696). Independent of social, family, employers' characteristics and prior health problems, the findings from a multivariate, stratified Cox regression analysis suggest there is excessive mortality among the over-educated, and a protective effect of under-education among native-born Swedish men and women. © 2015 Foundation for the Sociology of Health & Illness. Published by John Wiley & Sons Ltd.

Ljungqvist F.C.,University of Stockholm
Geografiska Annaler, Series A: Physical Geography | Year: 2010

A new temperature reconstruction with decadal resolution, covering the last two millennia, is presented for the extratropical Northern Hemisphere (90-30°N), utilizing many palaeo-temperature proxy records never previously included in any large-scale temperature reconstruction. The amplitude of the reconstructed temperature variability on centennial time-scales exceeds 0.6°C. This reconstruction is the first to show a distinct Roman Warm Period c. ad 1-300, reaching up to the 1961-1990 mean temperature level, followed by the Dark Age Cold Period c. ad 300-800. The Medieval Warm Period is seen c. ad 800-1300 and the Little Ice Age is clearly visible c. ad 1300-1900, followed by a rapid temperature increase in the twentieth century. The highest average temperatures in the reconstruction are encountered in the mid to late tenth century and the lowest in the late seventeenth century. Decadal mean temperatures seem to have reached or exceeded the 1961-1990 mean temperature level during substantial parts of the Roman Warm Period and the Medieval Warm Period. The temperature of the last two decades, however, is possibly higher than during any previous time in the past two millennia, although this is only seen in the instrumental temperature data and not in the multi-proxy reconstruction itself. Our temperature reconstruction agrees well with the reconstructions by Moberg et al. (2005) and Mann et al. (2008) with regard to the amplitude of the variability as well as the timing of warm and cold periods, except for the period c. ad 300-800, despite significant differences in both data coverage and methodology. © The authors 2010 Geografiska Annaler: Series A © 2010 Swedish Society for Anthropology and Geography.

Bots P.W.G.,Technical University of Delft | Schluter M.,University of Stockholm
Ecology and Society | Year: 2014

Frameworks play an important role in analyzing social-ecological systems (SESs) because they provide shared concepts and variables that enable comparison between and accumulation of knowledge across multiple cases. One prominent SES framework focusing on local resource use has been developed by Elinor Ostrom and her colleagues. This framework is an extensive multi-tier collection of concepts and variables that have demonstrated relevance for explaining outcomes in a large number of case studies in the context of fishery, water, and forestry common-pool resources. The further development of this framework has raised a number of issues related to the formal relationships between the large number of concepts and variables involved. In particular, issues related to criteria for ordering the concepts into tiers, adding new concepts, defining outcomes metrics, and representing dynamics in the framework have been identified. We address these issues by applying methods from research fields that study formal relationships between concepts such as domain-specific languages, knowledge representation, and software engineering. We find that SES frameworks could include the following seven formal components: variables, concepts, attribution relationships, subsumption relationships, process relationships, aggregation relationships, and evaluation metrics. Applying these components to the Ostrom framework and a case study of recreational fishery, we find that they provide clear criteria for structuring concepts into tiers, defining outcome metrics, and representing dynamics. The components identified are generic, and the insights gained from this exercise may also be beneficial for the development of other SES frameworks. © 2014 by the author(s).

Manzuna Sapu C.,University of Cologne | Backvall J.-E.,University of Stockholm | Deska J.,University of Cologne
Angewandte Chemie - International Edition | Year: 2011

Crude lipase from porcine pancreas acts as a highly efficient biocatalyst in the enantioselective transesterification of prochiral allendiols. Following a simple synthetic protocol, highly functionalized axially chiral allenes are obtained in high yields and excellent enantiopurity (see scheme). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Blom V.,University of Stockholm
Work | Year: 2012

Objective: A high work involvement is considered central in the burnout process. Yet, research investigating how high work involvement and psychosocial stressors relate to burnout is scarce. High involvement in terms of performance-based self-esteem (PBSE) refers to individuals' strivings to validate self-worth by achievements, a disposition linked to poor health. The aim of the present study was to examine longitudinally PBSE in relation to burnout while also taking into account work- and private life stressors. Participants: The sample consisted of 2121 working women and men. Methods: Main- and mediation effects were investigated using hierarchical regression analysis. Results: The results showed performance-based self-esteem mediated partially between the stressors and burnout. Performance-based self-esteem was the strongest predictor of burnout over time, followed by private life stressors. Women experienced more work stress than did men. Men had stronger associations between work stressors and burnout, while women had stronger associations between performance-based self-esteem and burnout. Conclusions: Individual characteristics along with both private life and work stressors are important predictors of burnout. Factors associated with burnout differ somewhat between women and men. © 2012 - IOS Press and the authors. All rights reserved.

Roumeliotis F.,University of Stockholm
International Journal of Drug Policy | Year: 2015

Background: This article critically examines the political dimension of prevention science by asking how it constructs the problems for which prevention is seen as the solution and how it enables the monitoring and control of these problems. It also seeks to examine how prevention science has established a sphere for legitimate political deliberation and which kinds of statements are accepted as legitimate within this sphere. Methods: The material consists of 14 publications describing and discussing the goals, concepts, promises and problems of prevention science. The analysis covers the period from 1993 to 2012. Results: The analysis shows that prevention science has established a narrow definition of "prevention", including only interventions aimed at the reduction of risks for clinical disorders. In publications from the U.S. National Institute of Drug Abuse, the principles of prevention science have enabled a commitment to a zero-tolerance policy on drugs. The drug using subject has been constructed as a rational choice actor lacking in skills in exerting self-control in regard to drug use. Prevention science has also enabled the monitoring and control of expertise, risk groups and individuals through specific forms of data gathering. Through the juxtaposition of the concepts of "objectivity" and "morality", prevention science has constituted a principle of delineation, disqualifying statements not adhering to the principles of prevention science from the political field, rendering ethical and conflictual dimensions of problem representations invisible. Conclusion: The valorisation of scientific accounts of drugs has acted to naturalise specific political ideals. It simultaneously marginalises the public from the public policy process, giving precedence to experts who are able to provide information that policy-makers are demanding. Alternative accounts, such as those based on marginalisation, poverty or discrimination are silenced within prevention science. © 2015 Elsevier B.V.

Barclay K.J.,University of Stockholm
Journal of Biosocial Science | Year: 2013

This study uses Swedish occupational register data to examine whether the proportion of men in administrative workplaces in the Swedish public service affects all-cause mortality risks amongst both males and females of working age. Using piecewise constant survival models to analyse occupational data from the Swedish administrative registers from 1995 to 2007, it was found that for males, a 1% increase in the proportion of males was associated with a 1.3% increase in mortality risk (hazard ratio, HR 1.013, 95% CI 1.007-1.020, p<0.001), but no association was found for females (HR 1.004, 95% CI 0.996-1.012, p=0.297). Adjustments were made for age, family status, education, occupational status, occupational segregation by sex, the total number of individuals in the workplace, level of government, region, period and variables reflecting the workplace structure by age, age by sex, occupation and education. A higher proportion of males may be related to (i) an increased exposure to risky health behaviours such as alcohol consumption and unhealthy dietary patterns, (ii) a tendency towards sickness presenteeism, and (iii) an increase in the levels of several well-established emotional stressors in the workplace, leading to an increased level of psychosocial stress. The findings and potential extensions of this research are discussed. © 2012 Cambridge University Press.

Rocha L.E.C.,Umea University | Liljeros F.,University of Stockholm | Holme P.,Umea University | Holme P.,Sungkyunkwan University
PLoS Computational Biology | Year: 2011

Sexual contact patterns, both in their temporal and network structure, can influence the spread of sexually transmitted infections (STI). Most previous literature has focused on effects of network topology; few studies have addressed the role of temporal structure. We simulate disease spread using SI and SIR models on an empirical temporal network of sexual contacts in high-end prostitution. We compare these results with several other approaches, including randomization of the data, classic mean-field approaches, and static network simulations. We observe that epidemic dynamics in this contact structure have well-defined, rather high epidemic thresholds. Temporal effects create a broad distribution of outbreak sizes, even if the per-contact transmission probability is taken to its hypothetical maximum of 100%. In general, we conclude that the temporal correlations of our network accelerate outbreaks, especially in the early phase of the epidemics, while the network topology (apart from the contact-rate distribution) slows them down. We find that the temporal correlations of sexual contacts can significantly change simulated outbreaks in a large empirical sexual network. Thus, temporal structures are needed alongside network topology to fully understand the spread of STIs. On a side note, our simulations further suggest that the specific type of commercial sex we investigate is not a reservoir of major importance for HIV. © 2011 Rocha et al.

Michel B.,French National Center for Scientific Research | Michel B.,University Paris - Sud | Bernander R.,University of Stockholm
BioEssays | Year: 2014

Replication of the main chromosome in the halophilic archaeon Haloferax volcanii was recently reported to continue despite deletion of all active replication origins. Equally surprising, the deletion strain grew faster than the parent strain. It was proposed that origin-less H. volcanii duplicate their chromosomes via recombination-dependent replication. Here, we recall our present knowledge of this mode of chromosome replication in different organisms. We consider the likelihood that it accounts for the viability of H. volcanii deleted for its main specific replication origins, as well as possible alternative interpretations of the results. The selective advantages of having defined chromosome replication origins are discussed from a functional and evolutionary perspective. © 2014 WILEY Periodicals, Inc.

Helleday T.,University of Oxford | Helleday T.,University of Stockholm
Carcinogenesis | Year: 2010

Although DNA double-strand breaks (DSBs) are substrates for homologous recombination (HR) repair, it is becoming apparent that DNA lesions produced at replication forks, for instance by many anticancer drugs, are more significant substrates for HR repair. Cells defective in HR are hypersensitive to a wide variety of anticancer drugs, including those that do not produce DSBs. Several cancers have mutations in or epigenetically silenced HR genes, which explain the genetic instability that drives cancer development. There are an increasing number of reports suggesting that mutation or epigenetic silencing of HR genes explains the sensitivity of cancers to current chemotherapy treatments. Furthermore, there are also many examples of re-expression of HR genes in tumours to explain drug resistance. Emerging data suggest that there are several different subpathways of HR, which can compensate for each other. Unravelling the overlapping pathways in HR showed that BRCA1- and BRCA2-defective cells rely on the PARP protein for survival. This synthetic lethal interaction is now being exploited for selective treatment of BRCA1- and BRCA2-defective cancers with PARP inhibitors. Here, I discuss the diversity of HR and how it impacts on cancer with a particular focus on how HR can be exploited in future anticancer strategies. © The Author 2010. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org.

Eklund L.,University of Stockholm
Journal of Gaming and Virtual Worlds | Year: 2015

This empirical study investigates social digital gaming habits through a national survey of Swedes aged 12-100. The enquiry concerns patterns of gaming and compares playing with different co-players in order to map out this growing practice among the general population. Logistic regression models are used to analyse the data. Results show support for the importance of separating different social gaming contexts according to the relational status of co-players: whom people play games with-family, friends or strangers-affects how players engage with games. Social gamers were younger, had higher achieved education, were more dedicated and spent more time on gaming. Furthermore, contrary to expectations, male gamers are more social than female gamers. Results show how digital gaming adapts to life rather than the other way around. Finally, digital gaming is shown to be situated in a complex weave of interactions and structures that go over and beyond the gaming itself. © 2015 Intellect Ltd Article.

Goldkuhl G.,Linkoping University | Goldkuhl G.,University of Stockholm
European Journal of Information Systems | Year: 2012

Qualitative research is often associated with interpretivism, but alternatives do exist. Besides critical research and sometimes positivism, qualitative research in information systems can be performed following a paradigm of pragmatism. This paradigm is associated with action, intervention and constructive knowledge. This paper has picked out interpretivism and pragmatism as two possible and important research paradigms for qualitative research in information systems. It clarifies each paradigm in an ideal-typical fashion and then conducts a comparison revealing commonalities and differences. It is stated that a qualitative researcher must either adopt an interpretive stance aiming towards an understanding that is appreciated for being interesting; or a pragmatist stance aiming for constructive knowledge that is appreciated for being useful in action. The possibilities of combining pragmatism and interpretivism in qualitative research in information systems are analysed. A research case (conducted through action research (AR) and design research (DR)) that combines interpretivism and pragmatism is used as an illustration. It is stated in the paper that pragmatism has influenced IS research to a fairly large extent, albeit in a rather implicit way. The paradigmatic foundations are seldom known and explicated. This paper contributes to a further clarification of pragmatism as an explicit research paradigm for qualitative research in information systems. Pragmatism is considered an appropriate paradigm for AR and DR. © 2012 Operational Research Society Ltd. All rights reserved.

Merkulov S.A.,University of Stockholm
Communications in Mathematical Physics | Year: 2010

Using a technique of wheeled props we establish a correspondence between the homotopy theory of unimodular Lie 1-bialgebras and the famous Batalin-Vilkovisky formalism. Solutions of the so-called quantum master equation satisfying certain boundary conditions are proven to be in 1-1 correspondence with representations of a wheeled dg prop which, on the one hand, is isomorphic to the cobar construction of the prop of unimodular Lie 1-bialgebras and, on the other hand, is quasi-isomorphic to the dg wheeled prop of unimodular Poisson structures. These results allow us to apply properadic methods for computing formulae for a homotopy transfer of a unimodular Lie 1-bialgebra structure on an arbitrary complex to the associated quantum master function on its cohomology. It is proven that in the category of quantum BV manifolds associated with the homotopy theory of unimodular Lie 1-bialgebras quasi-isomorphisms are equivalence relations. It is shown that Losev-Mnev's BF theory for unimodular Lie algebras can be naturally extended to the case of unimodular Lie 1-bialgebras (and, eventually, to the case of unimodular Poisson structures). Using a finite-dimensional version of the Batalin-Vilkovisky quantization formalism it is rigorously proven that the Feynman integrals computing the effective action of this new BF theory describe precisely homotopy transfer formulae obtained within the wheeled properadic approach to the quantum master equation. Quantum corrections (which are present in our BF model to all orders of the Planck constant) correspond precisely to what are often called "higher Massey products" in the homological algebra. © Springer-Verlag 2010.

Mortberg E.,University of Stockholm
Psychiatry Research | Year: 2014

The tripartite model of working alliance, including the therapeutic bond and agreement on tasks and goals, was examined in 54 patients who received individual or group cognitive behavior therapy (CBT) for social anxiety disorder (SAD) in a randomized trial. Alliance was significantly stronger in individual relative to group CBT but generally not related to outcome. © 2014 Elsevier Ireland Ltd.

Gebauer D.,University of Konstanz | Kellermeier M.,University of Konstanz | Gale J.D.,Curtin University Australia | Bergstrom L.,University of Stockholm | Colfen H.,University of Konstanz
Chemical Society Reviews | Year: 2014

Crystallisation is at the heart of various scientific disciplines, but still the understanding of the molecular mechanisms underlying phase separation and the formation of the first solid particles in aqueous solution is rather limited. In this review, classical nucleation theory, as well as established concepts of spinodal decomposition and liquid-liquid demixing, is introduced together with a description of the recently proposed pre-nucleation cluster pathway. The features of pre-nucleation clusters are presented and discussed in relation to recent modifications of the classical and established models for phase separation, together with a review of experimental work and computer simulations on the characteristics of pre-nucleation clusters of calcium phosphate, calcium carbonate, iron(oxy)(hydr)oxide, silica, and also amino acids as an example of small organic molecules. The role of pre-nucleation clusters as solute precursors in the emergence of a new phase is summarized, and the link between the chemical speciation of homogeneous solutions and the process of phase separation via pre-nucleat