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Bergen, Norway

The University of Bergen is located in Bergen, Norway. Although founded as late as 1946, academic activity had taken place at Bergen Museum as far back as 1825. The university today serves more than 14,500 students, and is one of eight universities in Norway. Wikipedia.


Lunde L.,University of Bergen
European Journal of Health Economics | Year: 2013

This paper provides an analysis on the use of 15D and EQ-5D to measure health related quality of life. Measures like these are often used interchangeably in cost-effectiveness studies. However, it is unclear whether they measure the same level of health in the same patients. The empirical performance of the two multi-attribute utility instruments is tested in terms of feasibility, utility score, linear relationship and agreement by using a novel Norwegian data set. The paper also includes an analysis of how the instruments rank individuals in terms of health status, and their discriminatory power are tested. The results show that EQ-5D and 15D should not be used interchangeably in economic evaluations. EQ-5D is likely to give a more favourable cost utility ratio than 15D. The utility scores generated from the two instruments differ significantly different from each other, even though they correlate well. The instruments also rank individuals in terms of health status differently. © 2012 Springer-Verlag.


Hatlebakk J.G.,University of Bergen
Best Practice and Research: Clinical Gastroenterology | Year: 2010

Although gastro-oesophageal reflux disease is basically a clinical diagnosis, oesophago-gastroduodenoscopy is essential to assess the type and severity of tissue damage. The main role for endoscopy is to detect metaplastic or premalignant changes complicating gastro-oesophageal reflux, and allow for surveillance. Routine biopsies are potentially useful to increase the diagnostic precision in case of minimal mucosal abnormalities. Management algorithms should include endoscopy to be performed early in the course of disease in most patients, even in the absence of alarm symptoms. Routine use of the Los Angeles classification of oesophagitis and the Prague classification for metaplasia is necessary for a precise description and biopsy sampling. Magnification chromoendoscopy is particularly useful in the hands of experienced endoscopists, whereas novel technologies including confocal laser endomicroscopy may become an important method in specialised centres to optimise the surveillance of premalignant mucosa. © 2010 Elsevier Ltd. All rights reserved.


Huismans R.S.,University of Bergen | Beaumont C.,Dalhousie University
Earth and Planetary Science Letters | Year: 2014

Even though many basic properties of non-volcanic rifted margins are predicted by uniform extension of the lithosphere, uniform extension fails to explain other important characteristics. Particularly significant discrepancies are observed at: 1) the Iberia-Newfoundland conjugate margins (Type I), where large tracts of continental mantle lithosphere are exposed at the seafloor, and at 2) ultra-wide central South Atlantic margins (Type II) where continental crust spans wide regions below which it appears that lower crust and mantle lithosphere were removed. Neither corresponds to uniform extension in which crust and mantle thin by the same factor. Instead, either the crust or mantle lithosphere has been preferentially removed during extension. We show that the Type I and II styles are respectively reproduced by dynamical numerical lithospheric stretching models (Models I-A/C and II-A/C) that undergo depth-dependent extension. In this notation A and C imply underplating of the rift zone during rifting by asthenosphere and lower cratonic lithosphere, respectively. We also present results for models with a weak upper crust and strong lower crust, Models III-A/C, to show that lower crust can also be removed from beneath the rift zone by horizontal advection with the mantle lithosphere. From the model results we infer that these Type I, II, and III margin styles are controlled by the strength of the mid/lower crust, which determines the amount of decoupling between upper and lower lithosphere during extension and the excision of crust or mantle. We also predict the styles of sedimentary basins that form on these margins as a test of the concepts presented. © 2014 Elsevier B.V.


Pruess K.,Lawrence Berkeley National Laboratory | Nordbotten J.,University of Bergen
Transport in Porous Media | Year: 2011

We have used the TOUGH2-MP/ECO2N code to perform numerical simulation studies of the long-term behavior of CO2 stored in an aquifer with a sloping caprock. This problem is of great practical interest, and is very challenging due to the importance of multi-scale processes. We find that the mechanism of plume advance is different from what is seen in a forced immiscible displacement, such as gas injection into a water-saturated medium. Instead of pushing the water forward, the plume advances because the vertical pressure gradients within the plume are smaller than hydrostatic, causing the groundwater column to collapse ahead of the plume tip. Increased resistance to vertical flow of aqueous phase in anisotropic media leads to reduced speed of up-dip plume advancement. Vertical equilibrium models that ignore effects of vertical flow will overpredict the speed of plume advancement. The CO2 plume becomes thinner as it advances, but the speed of advancement remains constant over the entire simulation period of up to 400 years, with migration distances of more than 80 km. Our simulations include dissolution of CO2 into the aqueous phase and associated density increase, and molecular diffusion. However, no convection develops in the aqueous phase because it is suppressed by the relatively coarse (sub-) horizontal gridding required in a regional-scale model. A first crude sub-grid-scale model was developed to represent convective enhancement of CO2 dissolution. This process is found to greatly reduce the thickness of the CO2 plume, but, for the parameters used in our simulations, does not affect the speed of plume advancement. © 2011 The Author(s).


Michaelsen T.C.,University of Bergen
Scandinavian Journal of Forest Research | Year: 2016

This study aims to identify which tree species bats use as maternity roosts in woodland in southern Norway and, to assess the effectiveness of bat boxes as potential mitigating measures if roosts are lost to forestry or other factors. Radio telemetry was used to find roosts in summer during late pregnancy and through the lactation period by tagging two common species; Daubenton's bats Myotis daubentonii (Kuhl 1817) and soprano pipistrelles Pipistrellus pygmaeus (Leach 1825). In addition, tree roosts were searched using ultrasound detectors at three sites. A total of 35 roosts in natural crevices were found using radio telemetry and through searches with ultrasound detectors and 31 of these roosts were in hollow trees, the majority in aspens Populus tremula L. (n = 30). Some tree roosts were even used by the northern bat Eptesicus nilssonii (Keyserling & Blasius 1839) which is considered a house-dwelling species in Norway. Aspens have some qualities preferred by bats and were both warmer and safer than other hollow tree species in this study area. Bat boxes are used as maternity roosts mainly by soprano pipistrelles at these latitudes, thus at present, there is no suitable alternative to hollow trees that would satisfy all tree-dwelling bat species. © 2016 Taylor & Francis


Castellani M.,University of Bergen
Neurocomputing | Year: 2013

Most methods for the evolutionary generation of multi-layer perceptron classifiers use a divide-and-conquer strategy, where the tasks of feature selection, structure design, and weight training are performed separately. The concurrent evolution of the whole classifier has been seldom attempted and its effectiveness has never been exhaustively benchmarked. This paper presents an experimental study on the merits of this latter approach. Two schemes were investigated. The first method evolves simultaneously the neural network structure and input feature vector, and trains via a standard learning procedure the candidate solutions (wrapper approach). The second method evolves simultaneously the whole classifier (embedded approach). The performance of these two algorithms was compared to that of two manual and two automatic neural network optimisation techniques on thirteen well-known pattern recognition benchmarks. The experimental results revealed the specific strengths and weaknesses of the six algorithms. Overall, the evolutionary embedded method obtained good results in terms of classification accuracy and compactness of the solutions. The tests indicated that the outcome of the feature selection task has a major impact on the accuracy and compactness of the solutions. Evolutionary algorithms perform best on feature spaces of small and medium size, and were the most effective at rejecting redundant features. Classical filter-based algorithms based on feature correlation are preferable on undersampled data sets. Correlation- and saliency-based selection was the most effective method in the presence of a large number of irrelevant features. The applicability and performance of the wrapper algorithm was severely limited by the computational costs of the approach. © 2012 Elsevier B.V.


Bentsen S.B.,Stord/Haugesund University College | Rokne B.,University of Bergen | Wahl A.K.,University of Oslo
Scandinavian Journal of Caring Sciences | Year: 2013

Background: Chronic obstructive pulmonary disease (COPD) is associated with lower health-related quality of life (HRQOL). Previous research has focused primarily on HRQOL in these patients, whereas few studies have compared HRQOL between patients with COPD and the general population. Aim: The aim of this study was to evaluate differences in HRQOL between patients with COPD stage 2 to COPD stage 4 waiting to begin an outpatient pulmonary rehabilitation (PR) programme and Norwegian individuals with and without other chronic conditions. Methods: A comparative survey design was used in this study of 100 patients with COPD waiting to begin PR and 3594 individuals from the general population. The SF-36 questionnaire was used to evaluate HRQOL. Results: Compared with the healthy general population, COPD patients waiting to begin PR had lower scores on all SF-36 components and on the physical and mental health summary components (p < 0.001). Scores for physical function, physical role, general health, vitality, social function, emotional role and the physical health component differed markedly between patients and the general population. Patients with COPD stage 4 had lower HRQOL than did the general population and those with COPD stage 2 and COPD stage 3. Conclusions: The burden of COPD significantly affects HRQOL in patients with COPD waiting to begin PR, and those with COPD stage 4 are most affected. Action should be taken to support especially those patients with COPD stage 4. © 2012 Nordic College of Caring Science.


Eigen G.,University of Bergen
Journal of Physics: Conference Series | Year: 2015

We present herein the most recent BABAR results on direct CP asymmetry measurements in B → Xsγ, on partial branching fraction and CP asymmetry measurements in B → Xsℓ+ℓ-, on a search for B → π/ηℓ+ℓ- decays, on a search for lepton number violation in B+ → X-ℓ+ℓ'+ modes and a study of B0 → ωω and B0 → ωφ decays.


Malterud K.,University of Bergen
Scandinavian journal of public health | Year: 2016

OBJECTIVE: In this article, I want to promote theoretical awareness and commitment among qualitative researchers in general practice and suggest adequate and feasible theoretical approaches.APPROACH: I discuss different theoretical aspects of qualitative research and present the basic foundations of the interpretative paradigm. Associations between paradigms, philosophies, methodologies and methods are examined and different strategies for theoretical commitment presented. Finally, I discuss the impact of theory for interpretation and the development of general practice knowledge.MAIN POINTS: A scientific theory is a consistent and soundly based set of assumptions about a specific aspect of the world, predicting or explaining a phenomenon. Qualitative research is situated in an interpretative paradigm where notions about particular human experiences in context are recognized from different subject positions. Basic theoretical features from the philosophy of science explain why and how this is different from positivism. Reflexivity, including theoretical awareness and consistency, demonstrates interpretative assumptions, accounting for situated knowledge. Different types of theoretical commitment in qualitative analysis are presented, emphasizing substantive theories to sharpen the interpretative focus. Such approaches are clearly within reach for a general practice researcher contributing to clinical practice by doing more than summarizing what the participants talked about, without trying to become a philosopher.CONCLUSIONS: Qualitative studies from general practice deserve stronger theoretical awareness and commitment than what is currently established. Persistent attention to and respect for the distinctive domain of knowledge and practice where the research deliveries are targeted is necessary to choose adequate theoretical endeavours. © 2015 the Nordic Societies of Public Health.


Berntsen J.,University of Bergen | Oey L.-Y.,Princeton University
Ocean Dynamics | Year: 2010

Sigma-coordinate ocean models are attractive because of their abilities to resolve bottom and surface boundary layers. However, these models can have large internal pressure gradient (IPG) errors. In this paper, two classes of methods for the estimation of the IPGs are assessed. The first is based on the integral approach used in the Princeton Ocean Model (POM). The second is suggested by Shchepetkin and McWilliams (2003) based on Green's theorem; thus, area integrals of the pressure forces are transformed into line integrals. Numerical tests on the seamount problem, as well as on a northwestern Atlantic grid using both classes of methods, are presented. For each class, second-, fourth-, and sixth-order approximations are tested. Results produced with a fourth-order compact method and with cubic spline methods are also given. The results show that the methods based on the POM approach in general give smaller errors than the corresponding methods given in Shchepetkin and McWilliams (2003). The POM approach also is more robust when noise is added to the topography. In particular, the IPG errors may be substantially reduced by using the computationally simple fourth-order method from McCalpin (1994). © Springer-Verlag 2009.


A new species of Phrixosoma from Tanzania is described and illustrated. This is a unique species for the genus in having a strongly concave female frons. Several characters are described for the first time for this genus, including male and female genitalia, mouthparts, thoracic sutures, and several overlooked features of the meso- and metatibiae and sternal processes. Copyright © 2012 Magnolia Press.


Geffen A.J.,University of Bergen | Nash R.D.M.,Norwegian Institute of Marine Research
Fisheries Research | Year: 2012

Egg incubation experiments are the primary source of data for temperature-dependent development models used in the egg production method (EPM) for stock assessments. What at first appears as a relatively simple experiment, to incubate fertilized eggs at a variety of temperatures while recording the time they spend in each stage, proves to be a more complicated exercise. The criteria for these experiments, and considerations of source material, experimental systems, and sources of error are presented, with examples from previous experiments on a variety of species world-wide. The influence of different factors on the statistical models used in EPM is reviewed. To allow more robust generalizations and avoid the limitations of maternal effects a number of different parents and parental crosses should be used. The question of whether to replicate within batches, between batches, or between crosses or even over years is evaluated. Since individual eggs tend to develop at different rates (natural variability) consideration should be given to the use of populations or individual observations. In some species there are important stock specific differences in development rates, as well as differences in stage specific mortality rates. Egg quality (size or composition) also influences development rates in some species. These sources of variation should be incorporated into experiments on temperature-dependent development rates. Stock specific patterns should be considered before applying development rates to stocks that were not used in the original model formulation. Good quality experimental data on egg development rates are valuable for many applications in addition to EPM assessments, and the quality criteria are equally important for their use in ecosystem and climate modeling. © 2011 Elsevier B.V.


Andersen P.,University of Bergen
International Journal of Agricultural Sustainability | Year: 2012

Several research initiatives have promoted the revival of 'under-utilized' or 'orphan' crops, discursively portrayed as benign, pro-poor, adapted to marginal conditions, nutritious and modest in input requirements and strengthening agricultural sustainability. This paper presents the case of the under-utilized crop ricebean (Vigna umbellata), based on experience from the project FOSRIN (Food Security through Ricebean Research in India and Nepal). The crop is widely scattered in South Asia, but production is declining. This decrease is explained by obstacles throughout the value chains at a global scale (trade regulations, practice of Intellectual Property Rights-related rules for germplasm exchange) as well as at a local scale. The dis-adoption of the crop by farmers is linked to traits of existing landraces: growth habits, appearance and taste, and pest problems. This dis-adoption presents dilemmas for the biodiversity argument. If ricebean is to regain its position, efforts are needed in marketing and promotion and also in plant breeding and provision of improved seed material. It will require varieties that are able to meet farmers' desires in terms of growth habits, time to maturity, uniform seeds, good yield, resistance to pests and diseases, as well as able to fetch good market prices through attractive appearance, cooking qualities and organoleptic qualities. This will, inevitably, be at the expense of existing varieties with less competitive features, making the responsibility for conservation an issue for off-farm strategies. © 2012 Taylor & Francis.


Jorgensen P.M.,University of Bergen
Taxon | Year: 2012

A study of Flora Norvegica by Johan Ernst Gunnerus revealed that no less than 39 new species names were validly published in the work. Most of them have not previously been effectively typified, though several of the names are in current use. This is done here, except for those of three sponges (animals), four non-lichenized fungi and five mosses (those in the last-named group are pre-starting-point names). The names of two species, those currently known as Carex norvegica Retz. and Rhizocarpon oederi (Weber) Körber, would need to change as a result of this, unless conservation or rejection proposals to preserve these names are accepted.


Information on habitat, nest placement, phenology and clutch size in Red-backed Shrikes Lanius collurio was collected from a total of 71 nests in southern Norway during 1995-2009. In this area, which is situated at the north-western limit of the species' distribution, breeding was predictable in clear-cuts in pine Pinus sylvestris forest where junipers Juniperus communis made up a large part of the shrub layer. This contrasts with previous descriptions of typical shrike habitat in clear-cuts which focused on the availability of young spruce Picea abies trees. Nests were almost exclusively located in Junipers (92%), further emphasizing the importance of this bush species as part of the shrike habitat in the study area. Mean nest height was 113 cm (range 0-250 cm) and increased with height of the nesting bush (mean = 225, range 120-400 cm). However, this increase was lower than expected if the relationship was simply proportional, indicating that the birds prefer to place their nests low in the vegetation even if higher alternatives are available. Clutch size ranged from 1 to 7 eggs (mean = 5.1) and estimated dates of first eggs varied from 10 May to 16 June (median = 3 June). Breeding time varied significantly between years but there was no correlation between breeding time and clutch size. Both height of nest and height of the nest bush increased significantly with breeding season, and possible reasons for these findings are discussed.


Forsaa E.B.,University of Stavanger | Larsen J.P.,University of Stavanger | Wentzel-Larsen T.,University of Bergen | Alves G.,University of Stavanger
Neurology | Year: 2010

Objective: To identify independent risk factors of mortality in a community-based Parkinson disease (PD) cohort during prospective long-term follow-up. Methods: A community-based prevalent sample of 230 patients with PD from southwestern Norway was followed prospectively with repetitive assessments of motor and nonmotor symptoms from 1993 to 2005. Information on vital status until October 20, 2009, was obtained from the National Population Register in Norway. Cox proportional hazards models were applied to identify independent predictors of mortality during follow-up. Chronological age, Unified Parkinson's Disease Rating Scale (UPDRS) motor score, levodopa equivalent dose, probable REM sleep behavior disorder, psychotic symptoms, dementia, and use of antipsychotics were included as time-dependent variables, and age at onset (AAO) and sex as time-independent variables. Results: Of 230 patients, 211 (92%) died during the study period. Median survival time from motor onset was 15.8 years (range 2.2-36.6). Independent predictors of mortality during follow-up were AAO (hazard ratio [HR] 1.40 for 10-years increase, p = 0.029), chronological age (HR 1.51 for 10-years increase, p = 0.043), male sex (HR 1.63, p = 0.001), UPDRS motor score (HR 1.18 for 10-point increase, p < 0.001), psychotic symptoms (HR 1.45, p = 0.039), and dementia (HR 1.89, p = 0.001). Conclusions: This population-based long-term study demonstrates that in addition to AAO, chronological age, motor severity, and dementia, psychotic symptoms independently predict increased mortality in PD. In contrast, no significant impact of antipsychotic or antiparkinsonian drugs on survival was observed in our PD cohort. Early prevention of motor progression and development of psychosis and dementia may be the most promising strategies to increase life expectancy in PD. © 2010 by AAN Enterprises, Inc. All rights reserved.


Van De Vliert E.,University of Groningen | Van De Vliert E.,University of Bergen
Behavioral and Brain Sciences | Year: 2013

This paper examines why fundamental freedoms are so unevenly distributed across the earth. Climato-economic theorizing proposes that humans adapt needs, stresses, and choices of goals, means, and outcomes to the livability of their habitat. The evolutionary process at work is one of collectively meeting climatic demands of cold winters or hot summers by using monetary resources. Freedom is expected to be lowest in poor populations threatened by demanding thermal climates, intermediate in populations comforted by undemanding temperate climates irrespective of income per head, and highest in rich populations challenged by demanding thermal climates. This core hypothesis is supported with new survey data across 85 countries and 15 Chinese provinces and with a reinterpretative review of results of prior studies comprising 174 countries and the 50 states in the United States. Empirical support covers freedom from want, freedom from fear, freedom of expression and participation, freedom from discrimination, and freedom to develop and realize one's human potential. Applying the theory to projections of temperature and income for 104 countries by 2112 forecasts that (a) poor populations in Asia, perhaps except Afghans and Pakistanis, will move up the international ladder of freedom, (b) poor populations in Africa will lose, rather than gain, relative levels of freedom unless climate protection and poverty reduction prevent this from happening, and (c) several rich populations will be challenged to defend current levels of freedom against worsening climato-economic livability. Copyright © 2013 Cambridge University Press.


Harvey A.G.,University of California at Berkeley | Harvey A.G.,University of Bergen
Annual Review of Clinical Psychology | Year: 2011

Evidence for the importance of sleep in the mood disorders has mushroomed over the past decade. Among adolescents and adults with a mood disorder, sleep disturbance is a risk factor for episodes, can contribute to relapse, has an adverse impact on emotion regulation, is critical for cognitive functioning, compromises health, and may contribute to substance use comorbidity and suicidality. This evidence has triggered a shift away from viewing sleep disturbance as an epiphenomenon, toward viewing sleep disturbance as an important but under-recognized mechanism in the multifactorial cause and maintenance of the mood disorders. Because the biology underpinning the sleep and circadian system is an open system, readily influenced by inputs from the environment, sleep in the mood disorders represents a unique and exciting domain for interdisciplinary research across behavioral, social, cognitive, and neurobiological levels of explanation. Together, the accumulated evidence has informed a range of novel, powerful, simple, and inexpensive treatments with potential for massive improvements to public health, including improving quality of life, reducing length and severity of episodes, and reducing the risk of subsequent episodes in the large number of individuals who suffer from mood disorders. Copyright © 2011 by Annual Reviews. All rights reserved.


Moe R.E.,University of Bergen
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

We investigate document clustering through adaptation of Zamir and Etzioni's method for Suffix Tree Clustering. We modified it with substantial improvements in effectiveness and efficiency compared to the original algorithm. © 2014 Springer International Publishing Switzerland.


Kaiser M.,University of Bergen
Bailliere's Best Practice and Research in Clinical Gastroenterology | Year: 2014

This paper presents some selected issues currently discussed about the integrity of science, and it argues that there exist serious challenges to integrity in the various sciences. Due to the involved conceptual complexities, even core definitions of scientific integrity have been disputed, and core cases of scientific misconduct influenced the public discussion about them. It is claimed that ethics and law may not always go well together in matters of scientific integrity. Explanations of the causes of scientific misconduct vary, and defining good scientific practices is not a straightforward task. Even though the efficacy of ethics courses to improve scientific integrity can be doubted, and universities probably need to come up with more innovative formats to improve ethics in scientific training, ethics talk may be the only practical remedy. © 2014.


Gjertsen B.T.,University of Bergen
Expert Review of Anticancer Therapy | Year: 2011

Evaluation of: Balgobind BV, Marry M, van den Heuvel-Eibrink MM et al. Evaluation of gene expression signatures predictive for cytogenetic and molecular subtypes of pediatric acute myeloid leukemia. Haematologica 96(2), 221-230 (2010). Treatment of children "s acute lymphoblastic leukemia has been at the forefront of conventional chemotherapy development. Despite outstanding results in long-term survival of acute lymphoblastic leukemia, development of therapies for acute myeloid leukemia (AML) have lagged behind. AML in children demonstrate similar long-term survival compared with adults 18-65 years of age: 40-50% overall long-term survival. AML is a heterogeneous disease in both adults and children, but the presence of recurrent chromosome translocations and mutations in children are lower than in adult AML. In particular, patients without chromosome aberrancies have been examined for stratification through examination of gene expression. The paper from Baglobind and coauthors proposes a useful prognostication by gene-expression analysis of 75 gene pairs in 40% of patient cases, accurately discriminating mixed lineage leukemia (MLL) gene rearrangement, t(8;21)(q22;q22), inv(16)(p13q22), t(15;17)(q21;q22) and t(7;12)(q36;p13)-positive AML. Gene-expression analysis of AML has provided an important research tool for uncovering information about AML biology that can be used for the development of novel therapies. © 2011 Expert Reviews Ltd.


Harris A.,University of Bergen
Rural and remote health | Year: 2010

INTRODUCTION: The diurnal rhythm of saliva cortisol and its association to adaptation, performance and health were examined in personnel over-wintering at two British Antarctic stations. METHODS: In total, 55 healthy individuals (49 males, 6 females) participated in the study. Cortisol in saliva was sampled on 3 consecutive days (at awakening, 15 and 45 min after waking, at 15.00 h, and 22.00 h) immediately after arrival at the station, midwinter, and the last week before departure. Subjective health complaints were also measured at arrival, midwinter, and the last week before departure, while depression (Burnam screen for depression) and positive and negative affect (PANAS) were measured at midwinter only. At the end of the winter appointment, base commanders evaluated the performance of all personnel. RESULTS: The variations in external light (darkness during winter, midnight sun during arrival and departure) did not influence the diurnal rhythms. The normal peak level in the morning, and the normal and gradual fall towards the evening were observed at arrival, midwinter, and before departure. Immediately after arrival the cortisol values were relatively high and correlated positively with base commander's evaluation of performance. During midwinter, approximately 58% scored for depression on the Burnam scale. However, when examining these data more closely, only 4 participants (7%) reported depression, the main reason for the high score on the depression scale was related to sleep problems and tiredness. CONCLUSIONS: There was no indication that over-wintering led to any disturbance in the diurnal rhythm of cortisol in British Antarctic personnel. There were no other indications of any 'over-wintering syndrome' than reports of subjective sleep problems and tiredness.


Bruserud O,University of Bergen
Current pharmaceutical biotechnology | Year: 2016

Even though malnutrition is associated with an adverse prognosis after allogeneic stem cell transplantation, few studies have addressed the question what is the optimal nutritional support for these patients. There is a general agreement that the body weight, body mass index and nutritional intake can be used to guide the post-transplant nutritional support; enteral nutrition may then be tried but most patients will require parenteral nutrition. There is no scientific basis for further standardization of post-transplant nutritional support. The nutritional status with regard to amino acid as well as fatty acid metabolism and vitamin levels are important for immunoregulation. Several amino acids and their metabolites function as signaling molecules through their binding to specific receptors, and they are thereby become important both in dendritic cell differentiation and T cell activation and the metabolic switch that often occurs during the activation of immunocompetent cells. We review previous studies of nutritional support in allotransplant recipients and discuss possible molecular mechanisms involved in metabolic immunoregulation and the development of post-transplant immune-mediated complications.


Gjertsen B.T.,University of Bergen
Current pharmaceutical biotechnology | Year: 2016

Acute myeloid leukemia (AML) is characterized by extensive clinical and biological heterogeneity. Despite vast advances in understanding the molecular pathology in AML during the last two decades few new AML therapeutics have been approved by the European Medicines Agency. Since 2005 only the epigenetic modulators decitabine and azacytidine, as well as histamine (plus interleukin- 2) have been approved against AML. None of these have outstanding efficiency, and decitabine and azacytdine have only been incorporated in frontline therapy of AML with limited enthusiasm. The majority of AML patients are frail and elderly, and lack of mild but effective agents for this patient cohort constitutes a major unmet need as overall survival remains poor. Along with the recent advancements in the molecular characterization of AML, numerous targeted therapies have been tested in clinical trials. In this review, we discuss the biological rationale for a selection of these novel therapeutic approaches, including epigenetic modifiers, agents targeting signalling pathways and inhibitors of nuclear-cytoplasmic shuttling. Further we discuss some of the possible shortcomings in current trial design that could explain the apparent incoherence between our improved biological knowledge and the lack of progress in therapy development of AML.


Zarbin M.,University of Bergen
Drug Discovery Today: Therapeutic Strategies | Year: 2012

Transplanted cells can secrete numerous molecules that may exert a beneficial effect on the host retina and/or choroid even if they do not cure the underlying disease. Ideally, with a single transplant operation, many different pathways can be modified, which may reduce the chance of 'escape' associated with typical pharmacotherapy as well as the need for repeated drug administration. In addition, transplanted cells can replace dead cells (e.g. photoreceptors). Because of their pluripotency and unlimited proliferative capacity, stem cells seem to be a logical choice for starting material because they can be produced en masse safely and they can be induced to differentiate into ocular cells with potential for replacement and rescue therapy. Although preclinical studies demonstrate the feasibility of using embryonic stem cells and induced pluripotent stem cells for treating degenerative retinal diseases associated with abnormalities in the retinal pigment epithelium and/or photoreceptors, some issues may limit the use of stem cells in clinical practice. These issues include: immunogenicity of the cells, stability of cell phenotype (both inherent and environment-induced), the propensity to form tumors in situ, the abnormal microenvironment that can accompany degenerative disease and the synaptic rewiring that accompanies retinal degeneration. In the case of non-exudative age-related macular degeneration, cell transplants might prevent progression of geographic atrophy (through replacement of dysfunctional or dead RPE) and might even bring about some visual improvement in selected cases (through rescue of photoreceptors that are dying but not dead). Cell-based therapy may one day be sight-restoring for patients who are blind due to retinal degeneration of various etiologies. RPE transplantation is an attractive starting point for this sort of therapy as these cells can integrate with the host retina easily. © 2012 Elsevier Ltd. All rights reserved.


In many parts of Europe, extensive changes in vegetation have taken place during recent decades. In Norway, forest expansion is a major trend, with an increase in volume of 20.3% during the period 1994-2008. The annual increase has more than doubled since 1967. This study was carried out to gain more insight into the complexity of vegetation dynamics and alterations in a lowland area on the coast of W Norway, and to identify the driving forces behind these changes. Field surveys were carried out with aerial photo interpretation and vegetation mapping. Spatial analysis was carried out using GIS. Historical sources were identified, interpreted, and used to generate information on land-use during recent centuries. Supplementary methods consisted of soil profile analysis and dendrochronology. Climate data were used to analyse climatic trends in the past 90 years since 1923. Forest expansion was a major trend during 1956-1994. In 1956, 49.5% of the area was covered by forest, and by 1994 the coverage had increased with 53.4%. Forestation continued during 1994-2003 and 2003-2007, but at rates far lower than in the previous period (4.0 and 3.8% increases, compared to 53.4%). Forest expansion was most extensive during 1956-1994, a period with no clear trend in mean July temperatures. A distinct increase in mean July temperatures occurred during the period 1994-2003 and again in 2003-2007, when the rate of forestation was far lower than in previous decades. This is an indication that a factor other than climate change is the most important driving force for vegetation change, forest expansion in particular. Forestation did not start simultaneously throughout all parts of the study area, but at different times on different landholdings. Forestation initially started on plots where livestock grazing first came to an end (in the 1930s), and lastly on plots where grazing came to an end three decades later, in the 1960s. The different starting times of forestation is reflected in the present age structure of the forest stands on the eight landholdings studied. The conclusion is drawn that changes in land-use are the major driving force behind the distinct process of forestation that occurred during the 20 th century. © Uni Bonn.


Liu J.,Beijing Normal University | Tai X.-C.,University of Bergen | Huang H.,Beijing Normal University | Huan Z.,Beijing Normal University
IEEE Transactions on Image Processing | Year: 2013

This paper proposes a general weighted $l^{2}-l0 norms energy minimization model to remove mixed noise such as Gaussian-Gaussian mixture, impulse noise, and Gaussian-impulse noise from the images. The approach is built upon maximum likelihood estimation framework and sparse representations over a trained dictionary. Rather than optimizing the likelihood functional derived from a mixture distribution, we present a new weighting data fidelity function, which has the same minimizer as the original likelihood functional but is much easier to optimize. The weighting function in the model can be determined by the algorithm itself, and it plays a role of noise detection in terms of the different estimated noise parameters. By incorporating the sparse regularization of small image patches, the proposed method can efficiently remove a variety of mixed or single noise while preserving the image textures well. In addition, a modified K-SVD algorithm is designed to address the weighted rank-one approximation. The experimental results demonstrate its better performance compared with some existing methods. © 2012 IEEE.


Bell R.F.,University of Bergen
Current Opinion in Supportive and Palliative Care | Year: 2012

Purpose of review: Ketamine misuse and abuse is on the increase. This review focuses on recent studies on ketamine toxicity in recreational users and possible implications for the use of ketamine in chronic pain therapy. Recent findings: Urological toxicity, hepatotoxicity and cognitive deficits are all reported as adverse effects of the recreational use of ketamine. Urological toxicity and hepatotoxicity have been reported as adverse effects of ketamine in pain therapy. Summary: These findings may have implications for the clinical use of ketamine in chronic noncancer pain conditions. Until safety issues are resolved, it is suggested that chronic pain treatment involving higher doses and repeated exposure to ketamine be restricted to the context of randomized, controlled trials or clinical audits. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.


Christoffersson A.,Uppsala University | Husebye E.S.,University of Bergen
Earth-Science Reviews | Year: 2011

It is now more than 35. years since our original work on seismic tomography commenced in June 1974 upon Keiiti Aki's arrival at Kjeller near Oslo. It was published by Aki et al. (1977) and has found wide-spread applications in numerous studies of the Earth's interior from crust to core and in addition triggered many theoretical ones as well. In those times, computer technologies were rather crude and this hampered our tomographic research. In particular, we were somewhat unhappy about both our Generalized Inverse (GI) and the Stochastic Inverse (SI) solutions because of the former being too bumpy and the latter involving vertical smoothing. These problems remain in evidence also in recent studies as will be demonstrated in this review work. We start with re-examining the ACH-original work and then introduce Gauss-Markov (GM) filtering offsetting the defects of both the generalized and stochastic inverses. We highlight the relative merits of our novel inversion method by real tests on the original Norsar P-residuals and the corresponding 5 layered lithosphere model using synthetic velocity anomalies. Then we repeated the original inversion experiment adding the GM solution. The outcome was that the original SI solution was useless; GI too bumpy while the GM solution was appealing both computationally and in the context of geotectonic interpretation. We found that alternative inversion procedures like those forwarded by Backus and Gilbert (1968) and by Pijpers and Thompson (1992), the latter for helioseismology, were not applicable. The reason is that our unknowns are relative velocity anomalies within separate model layers and thus violate basic assumptions in the mentioned procedures. We also discuss source and structure parameter separation and the recent 'double difference' approach in tomography based on local earthquake data. © 2011 Elsevier B.V.


Plessen K.J.,Center for Child and Adolescent Psychiatry Bispebjerg | Plessen K.J.,Copenhagen University | Plessen K.J.,University of Bergen
European Child and Adolescent Psychiatry | Year: 2013

Diagnostic categories of tic disorders include both transient and chronic tic disorders and Tourette's disorder. Changes for this group of disorders proposed for the forthcoming DSM-5 system include: (1) The term "stereotyped" will be eliminated in the definition of tics and the new definition will be applied consistently across all entities of tic disorders; (2) the diagnosis "Transient Tic Disorder" will change its name to "Provisional Tic Disorder"; (3) introduction of two new categories in individuals whose tics are triggered by illicit drugs or by a medical condition; (4) specification of chronic tic disorders into those with motor tics or with vocal tics only; (5) specification of the absence of a period longer than 3 months without tics will disappear for Tourette's Disorder. This overview discusses a number of implications resulting from these diagnostic modifications of the diagnostic classifications for use in the clinics. European guidelines for "Tourette's syndrome and other Tic disorders" were published in 2011 in the ECAP by the "European Society for the Study of Tourette Syndrome". The guidelines emphasize the complexity of these neuropsychiatric disorders that require interdisciplinary cooperation between medical professionals, but also patients, parents and teachers for planning of treatment. The main conclusion derived from the guideline for pharmacological treatment is the urgent need for rigorous studies that address the effectiveness of anti-tic medications. The guidelines also emphasize the importance of facilitating the dissemination of several behavioral treatment approaches, such as "Exposure Response Prevention", yet the most well documented being "Habit Reversal Training". © Springer-Verlag Berlin Heidelberg 2012.


Haugland D.,University of Bergen
Journal of Global Optimization | Year: 2016

The pooling problem is an extension of the minimum cost flow problem defined on a directed graph with three layers of nodes, where quality constraints are introduced at each terminal node. Flow entering the network at the source nodes has a given quality, at the internal nodes (pools) the entering flow is blended, and then sent to the terminal nodes where all entering flow streams are blended again. The resulting flow quality at the terminals has to satisfy given bounds. The objective is to find a cost-minimizing flow assignment that satisfies network capacities and the terminals’ quality specifications. Recently, it was proved that the pooling problem is NP-hard, and that the hardness persists when the network has a unique pool. In contrast, instances with only one source or only one terminal can be formulated as compact linear programs, and thereby solved in polynomial time. In this work, it is proved that the pooling problem remains NP-hard even if there is only one quality constraint at each terminal. Further, it is proved that the NP-hardness also persists if the number of sources and the number of terminals are no more than two, and it is proved that the problem remains hard if all in-degrees or all out-degrees are at most two. Examples of special cases in which the problem is solvable by linear programming are also given. Finally, some open problems, which need to be addressed in order to identify more closely the borderlines between polynomially solvable and NP-hard variants of the pooling problem, are pointed out. © 2015, Springer Science+Business Media New York.


Torabi A.,University of Bergen | Zarifi Z.,Uppsala University
International Journal of Rock Mechanics and Mining Sciences | Year: 2014

Cataclastic bands and their mechanical properties within two mineralogically different sandstones have been studied. In order to investigate the propagation energy of these bands, we have used dynamic elastic moduli calculated from laboratory measurements of ultrasonic velocities using a portable ultrasonic measuring system. As a product of cataclasis and compaction, elastic moduli (uniaxial compressive and shear moduli) of the bands are different from their corresponding host rocks leading to heterogeneity and anisotropy within sandstone reservoirs. Poisson's ratio decreases in the cataclastic bands of sandstone with high quartz content as a result of compaction, while it increases within cataclastic bands of sandstone with high clay and phyllosilicate content (more than 30%). Using the calculated propagation energy rates, we investigate which mode of deformation can be more dominant in the setting of our samples, propagation of deformation band as a result of strain hardening within the cataclastic band or crack propagation inside the deformation band due to strain softening prior to the propagation of band. We further estimate the maximum length of cracks inside a deformation band which can precede further growth of the deformation band. © 2013 Elsevier Ltd.


Fer I.,University of Bergen
Journal of Physical Oceanography | Year: 2014

Observations were made in April 2007 of horizontal currents, hydrography, and shear microstructure in the upper 500 m from a drifting ice camp in the central Arctic Ocean. An approximately 4-day-long time series, collected about 10 days after a storm event, shows enhanced near-inertial oscillations in the first half of the measurement period with comparable upward- and downward-propagating energy. Rough estimates of wind work and near-inertial flux imply that the waves were likely generated by the previous storm. The near-inertial frequency band is associated with dominant clockwise rotation in time of the horizontal currents and enhanced dissipation rates of turbulent kinetic energy. The vertical profile of dissipation rate shows elevated values in the pycnocline between the relatively turbulent underice boundary layer and the deeper quiescent water column. Dissipation averaged in the pycnocline is near-inertially modulated, and its magnitude decays approximately at a rate implied by the reduction of energy over time. Observations suggest that near-inertial energy and internal wave-induced mixing play a significant role in vertical mixing in the Arctic Ocean. © 2014 American Meteorological Society.


Yuan D.,Linkoping University | Haugland D.,University of Bergen
IEEE Transactions on Mobile Computing | Year: 2012

We consider the problem of constructing a shared broadcast tree (SBT) in wireless networks, such that the total power required for supporting broadcast initiated by all source nodes is minimal. In the well-studied minimum-energy broadcast (MEB) problem, the optimal tree varies by source. In contrast, SBT is source-independent, thus substantially reducing the overhead for information storage and processing. The SBT problem also differs from the range assignment problem (RAP), because the power for message forwarding in SBT, although being source-independent, depends on from which tree neighbor the message is received. We approach SBT from a computational optimization standpoint, and present a dual decomposition method applied to an optimization model that embeds multiple directed trees into a shared tree. For the dual decomposition method, some of the constraints in the model are preferably formulated implicitly. The dual decomposition scheme is coupled with a fast local search algorithm. We report computational results demonstrating the effectiveness of the proposed approach. In average, the performance gap to global optimality is less than three percent. © 2012 IEEE.


Evanger K.,University of Bergen
Optometry and Vision Science | Year: 2015

PURPOSE: To examine ocular lens parameters and structural changes to elucidate mechanisms underlying the myopic shift and cataract-related changes that occur in some patients during hyperbaric oxygen (HBO) therapy. METHODS: Scheimpflug images (Nidek EAS-1000) of the crystalline lens, measurements of scattered light, objective refraction, keratometry, tonometry, and axial length of the eye were obtained after the first day of HBO therapy and repeated when patients had completed 19 days of the treatment. RESULTS: Significant reduction in mean (±SD) optical density was found in the lens nucleus, −2.8 (±4.3) units (p = 0.009) and −2.2 (±4.1) units (p = 0.027) within circular and oval areas, respectively. Significant decrease in mean (±SD) backward scattered light was measured, −0.4 (±0.8) units (p = 0.022). Mean (±SD) myopic shift was −0.58 (±0.39) diopters (p < 0.001), whereas cortical optical density, forward scattered light, lenticular parameters, keratometry, tonometry, anterior chamber depth, and axial length of the eye appeared unchanged. CONCLUSIONS: Transient myopic shift reported in patients during HBO therapy is attributed to changes in the refractive index of the lens. No changes in lens curvatures or thickness were found after treatment. © 2015 American Academy of Optometry.


Ursin H.,University of Bergen
Psychoneuroendocrinology | Year: 2014

Sensitization is defined as a non-associative learning process occurring when repeated administrations of a stimulus result in a progressive amplification of a response (Shettleworth, 2010). The purpose of this review paper is to discuss whether brain sensitization is helpful in common health problems in man. The paper reviews data on brain sensitization covering increased behavioral, physiological, cognitive, and emotional responses in man and animals. The paper concludes that brain sensitization may be a helpful concept to understand subjective and "unexplained" health complaints (nonspecific muscle pain, mood changes, fatigue, and gastrointestinal complaints), and, therefore, relevant for evidence based treatment and prevention of these common health problems. © 2014 Elsevier Ltd.


Gjengedal H.,University of Bergen
The International journal of prosthodontics | Year: 2011

The aim of this study was to explore variables that might influence self-reported oral health and denture satisfaction in partially and completely edentulous patients. The study sample was recruited from 294 patients treated with complete dentures at the Department of Prosthodontics, Faculty of Dentistry, University of Bergen, Norway, between 1997 and 2005. The 172 respondents completed a self-administered questionnaire regarding demographics, denture status, appetite, avoiding food items, satisfaction with dentures, various aspects of wearing dentures, and the Oral Health Impact Profile (OHIP-20). The mean age of patients was 67 years; 52% were men. Sixty-seven percent of patients had complete maxillary and mandibular dentures, while 33% had a complete maxillary denture and a dentate mandible. There were no significant group differences regarding age, sex, general health, appetite, avoiding food items, chewing, speech, maxillary denture esthetics, or the OHIP-20. However, striking group differences were found in the number and nature of significant variables associated with reported oral health and denture satisfaction at all levels of analyses. Thus, oral health in the completely edentulous was associated with the OHIP-20, avoiding food items, and satisfaction with dentures, while in the partially edentulous, it was associated with maxillary denture retention and age. Similarly, satisfaction with dentures in the completely edentulous was associated with the OHIP-20, global oral health, and some clinical variables, while in the partially edentulous, it was associated with the OHIP-20 and some clinical variables. Predictors for oral health in the completely edentulous were the OHIP-20, speech, and avoiding certain food items; in the partially edentulous, they were denture retention and age. Predictors for denture satisfaction in the completely edentulous were the OHIP-20 and maxillary denture esthetics; in the partially edentulous, only maxillary denture comfort served as a predictor. Also, the completely edentulous reported better oral health and satisfaction with their dentures than the partially edentulous. The results of this study suggest that the completely and partially edentulous differ in variables associated with, and predictive for, both self-reported oral health and denture satisfaction.


Yang Y.,Stanford University | Van Den Broeck J.,University of Bergen | Wein L.M.,Stanford University
Proceedings of the National Academy of Sciences of the United States of America | Year: 2013

Several aid groups have proposed strategies for allocating ready-touse (therapeutic and supplementary) foods to children in developing countries. Analysis is needed to investigate whether there are better alternatives. We use a longitudinal dataset of 5,657 children from Bwamanda to construct a bivariate time-series model that tracks each child's height-for-age z score (HAZ) and weight-forheight z score (WHZ) throughout the first 5 y of life. Our optimization model chooses which individual children should receive readyto- use therapeutic or supplementary food based on a child's sex, age, HAZ, and WHZ, to minimize the mean number of disabilityadjusted life years (DALYs) per child during 6-60 mo of age [which includes childhood mortality calculated from a logistic regression and the lifelong effects of stunting (i.e., low HAZ)] subject to a budget constraint. Compared with the strategies proposed by the aid groups, which do not use HAZ information, the simple strategy arising from our analysis [which prioritizes children according to low values of a linear combination of HAZ, WHZ, and age and allocates the entire budget to therapeutic (i.e., 500 kcal/d) food for the prioritized children] reduces the number of DALYs by 9% (for the same budget) or alternatively incurs the same number of DALYs with a 61%reduction in cost.Whereas our qualitative conclusions appear to be robust, the quantitative results derived from our analysis should be treated with caution because of the lack of reliable data on the impact of supplementary food on HAZ and WHZ, the application of our model to a single cohort of children and the inclusion and exclusion errors related to imperfect food targeting.


Schroter H.G.,University of Bergen
Scandinavian Economic History Review | Year: 2012

It is taken as common sense that small countries have been more pressed and exploited by transnational enterprises than large ones. Economists call this the 'small-country-squeeze'. Our contribution tries to transfer the thesis to the micro-economic level: Did mighty international cartels exploit their cartel partners based in small countries more easily than enterprises from larger states? From a viewpoint of political logic, or everyday feeling, such a thesis looks straightforward. In the following we apply the thesis of small-country-squeeze to several cases of cartels during their peak period, 1919-1939, and find surprisingly little evidence for this 'common sense'. The assumption rather needs to be reversed: We should take non-discrimination as the normal case and try to find contradicting cases of discrimination. © 2012 Copyright Taylor and Francis Group, LLC.


Helseth L.E.,University of Bergen | Helseth L.E.,Michelsen Center for Iindustrial Measurement Science and Technology
Optics Express | Year: 2012

The characterization of dyes in various solvents requires determination of the absorption spectrum of the dye as well as the refractive index of the solvent. Typically, the refractive index of the solvent and the absorption spectrum of the solute are measured using separate experimental setups where significant liquid volumes are required. In this work the first optical measurement system that is able to do simultaneous measurements of the refractive index of the solvent and the spectral properties of the solute in a microscopic volume is presented. The laser dye Rhodamine 6G in glycerol is investigated, and the refractive index of the solution is monitored using the interference pattern of the light scattered off the channel, while its spectral properties is found by monitoring reflected light from the channel. © 2012 Optical Society of America.


Jordal B.H.,University of Bergen | Sequeira A.S.,Wellesley College | Cognato A.I.,Michigan State University
Molecular Phylogenetics and Evolution | Year: 2011

A large proportion of the hyperdiverse weevils are wood boring and many of these taxa have subsocial family structures. The origin and relationship between certain wood boring weevil taxa has been problematic to solve and hypotheses on their phylogenies change substantially between different studies. We aimed at testing the phylogenetic position and monophyly of the most prominent wood boring taxa Scolytinae, Platypodinae and Cossoninae, including a range of weevil outgroups with either the herbivorous or wood boring habit. Many putatively intergrading taxa were included in a broad phylogenetic analysis for the first time in this study, such as Schedlarius, Mecopelmus, Coptonotus, Dactylipalpus, Coptocorynus and allied Araucariini taxa, Dobionus, Psepholax, Amorphocerus-Porthetes, and some peculiar wood boring Conoderini with bark beetle behaviour. Data analyses were based on 128 morphological characters, rDNA nucleotides from the D2-D3 segment of 28S, and nucleotides and amino acids from the protein encoding gene fragments of CAD, ArgK, EF-1α and COI. Although the results varied for some of the groups between various data sets and analyses, one may conclude the following from this study: Scolytinae and Platypodinae are likely sister lineages most closely related to Coptonotus; Cossoninae is monophyletic (including Araucariini) and more distantly related to Scolytinae; Amorphocerini is not part of Cossoninae and Psepholax may belong to Cryptorhynchini. Likelihood estimation of ancestral state reconstruction of subsociality indicated five or six origins as a conservative estimate. Overall the phylogenetic results were quite dependent on morphological data and we conclude that more genetic loci must be sampled to improve phylogenetic resolution. However, some results such as the derived position of Scolytinae were consistent between morphological and molecular data. A revised time estimation of the origin of Curculionidae and various subfamily groups were made using the recently updated fossil age of Scolytinae (100. Ma), which had a significant influence on node age estimates. © 2011 Elsevier Inc.


Chen K.,University of Bergen
Clinics in Podiatric Medicine and Surgery | Year: 2010

Calcaneal osteomyelitis is a complicated clinical scenario, which is often very difficult to treat. It can occur in individuals of any age who are injured or immunocompromised, and once diagnosed, aggressive management should be initiated. Treatment ranges from antibiotics alone to radical debridement or amputation. If there is a delay in both diagnosis and treatment, calcaneal osteomyelitis can be limb threatening or even life threatening. © 2010 .


Natvik E.,University of Bergen
Qualitative health research | Year: 2013

Bariatric surgery provides sustainable weight loss and increased quality of life for most, but not all patients. To increase the knowledge of this complex patient group and their needs during follow-up, we aimed to describe the essential meaning of bariatric surgery patients' long-term experiences by using a phenomenological lifeworld approach. Eight patients were interviewed between 5 and 7 years after bariatric surgery. Life after bariatric surgery was described as living with tension, ambivalence, and reinforced attention toward one's own body. The tension was related to embodied change and altered relations to the social world. The patients express an ongoing demand for control of health-related habits and practices, and to not lose control over the body again. Surgical weight loss and improved physical function do not necessarily mean changed health-related habits and practices in the long term. Experiencing weight regain is connected with emotional stress, shame, and self-contempt.


Dorn F.,University of Bergen
Leibniz International Proceedings in Informatics, LIPIcs | Year: 2010

The problem of Subgraph Isomorphism is defined as follows: Given a pattern H and a host graph G on n vertices, does G contain a subgraph that is isomorphic to H? Eppstein [SODA 95, J'GAA 99] gives the first linear time algorithm for subgraph isomorphism for a fixed-size pattern, say of order k, and arbitrary planar host graph, improving upon the O(n√k)-time algorithm when using the "Color-coding" technique of Alon et al [J'ACM 95]. Eppstein's algorithm runs in time kO(k)n, that is, the dependency on k is superexponential. We improve the running time to 2O(k)n, that is, single exponential in k while keeping the term in n linear. Next to deciding subgraph isomorphism, we can construct a solution and count all solutions in the same asymptotic running time. We may enumerate ω subgraphs with an additive term O(ωk) in the running time of our algorithm. We introduce the technique of "embedded dynamic programming" on a suitably structured graph decomposition, which exploits the number and topology of the underlying drawings of the subgraph pattern (rather than of the host graph). © Frederic Dorn.


Naess H.,University of Bergen
Acta neurologica Scandinavica. Supplementum | Year: 2010

To assess the influence of depression prior to stroke (PD) on stroke severity on admittance, functional outcome (short- and long-term), mortality, and long-term depression (PSD). Consecutive acute stroke patients were screened for PD. The National Institute of Health Stroke Scale score was obtained on admission. Short-term functional state was registered by the modified Rankin scale and on long-term functional outcome by the Barthel Index. PSD was defined as depression subscale of the hospital anxiety and depression scale (HADSD) >or=11. HADSD and Barthel Index were obtained by postal questionnaire. Survival analyses were performed. Among 771 patients 21.7% had PD. Among 376 patients returning the questionnaire, 8.8% were depressed. On logistic regression analyses severity of stroke on admission, short-term, and long-term functional outcome were independently associated with PD. Logistic regression showed PSD to be independently associated with PD and being unmarried. Cox regression analyses showed that both PD and PSD were associated with high long-term mortality. This study has identified several factors associated with PSD. PD predicts more severe stroke on admittance and less functional improvement both in the short- and the long-term. Both PD and PSD predict higher long-term mortality.


Lokshtanov D.,University of Bergen | Marx D.,Hungarian Academy of Sciences
Information and Computation | Year: 2013

We study a family of graph clustering problems where each cluster has to satisfy a certain local requirement. Formally, let μ be a function on the subsets of vertices of a graph G. In the (μ,p,q)-Partition problem, the task is to find a partition of the vertices into clusters where each cluster C satisfies the requirements that (1) at most q edges leave C and (2) μ(C)≤p. Our first result shows that if μ is an arbitrary polynomial-time computable monotone function, then (μ,p,q)-Partition can be solved in time nO(q), i.e., it is polynomial-time solvable for every fixed q. We study in detail three concrete functions μ (the number of vertices in the cluster, number of nonedges in the cluster, maximum number of non-neighbors a vertex has in the cluster), which correspond to natural clustering problems. For these functions, we show that (μ,p,q)-Partition can be solved in time 2O(p)×nO(1) and in time 2 O(q)×nO(1) on n-vertex graphs, i.e., the problem is fixed-parameter tractable parameterized by p or by q. © 2012 Elsevier Inc. All rights reserved.


Opdal A.F.,University of Bergen
Biology Letters | Year: 2010

Prior to the 1920s, the northeast Arctic (NA) cod were caught at spawning grounds ranging from the southernmost to the northernmost parts of the Norwegian coast, but have for the last 50 yr mainly been caught around the Lofoten archipelago and northwards. The NA cod have their feeding and nursery grounds in the Barents Sea, and migrate south towards the Norwegian coast in the winter to spawn. This study uses commercial fisheries' data from landing ports along the entire Norwegian coast during the period 1866-1969 as evidence of long-term truncation and northerly shift of spawning grounds. Nearly all spawning grounds south of Lofoten have been abandoned, while an increasing proportion of the spawning stock only uses the northernmost areas of the Norwegian coast, Troms and Finnmark. The truncation can hardly be attributed to long-term climatic variations, but may result from an intensive size-selective trawl fishery in the Barents Sea causing a sudden increase in fishing mortality, probably altering the size structure and migratory capacity of the stock. © 2009 The Royal Society.


Lenhard B.,Imperial College London | Lenhard B.,Clinical Science Center | Lenhard B.,University of Bergen | Sandelin A.,Copenhagen University | Carninci P.,RIKEN
Nature Reviews Genetics | Year: 2012

Promoters are crucial for gene regulation. They vary greatly in terms of associated regulatory elements, sequence motifs, the choice of transcription start sites and other features. Several technologies that harness next-generation sequencing have enabled recent advances in identifying promoters and their features, helping researchers who are investigating functional categories of promoters and their modes of regulation. Additional features of promoters that are being characterized include types of histone modifications, nucleosome positioning, RNA polymerase pausing and novel small RNAs. In this Review, we discuss recent findings relating to metazoan promoters and how these findings are leading to a revised picture of what a gene promoter is and how it works. © 2012 Macmillan Publishers Limited. All rights reserved.


Kolstad J.R.,University of Bergen | Lindkvist I.,Chr Michelsen Institute
Health Policy and Planning | Year: 2013

Motivational crowding-out theory establishes that the effectiveness of financial incentive schemes, like pay-for-performance, crucially depends on the underlying social preferences of health workers. In this paper we study the extent to which heterogeneity in the strength and structure of social preferences is relatedto career choices by testing whether preferences vary systematically between Tanzanian health worker students who prefer to work in the private for-profit health sector and those who prefer to work in the public health sector. Despite its important policy implications, this issue has received little attention to date. By combining data from a questionnaire and an economic experiment, we find that students who prefer to work in the public health sector have stronger pro-social preferences than those who prefer to work in the private for-profitsector. © 2012 Author all rights reserved.


Fishery policies have largely developed in response to revealed problems with existing policy instruments. The last major innovation is the introduction of individual transferable quotas, ITQs. Experience thus far is promising. However, if history repeats itself, it is pertinent to start exploring further improvements. Among other things, concerns may be raised about the efficiency of ITQs, financial risks to owners of quotas and fishing vessels, and problems with fairness and collection of resource rent. These issues are studied with a laboratory experiment. Different from previous experiments it allows for trade of both quotas and vessels. In addition, the experiment tests an alternative institutional arrangement, namely auctioned seasonal quotas, ASQs. Neither of the two systems turns out to be as perfect as economic theory predicts. While the two systems are similar in some respects, the ASQ system allows for taxation of resource rent, and surprisingly, it may be the system with the lowest financial risk for fishing firms. © 2011 Elsevier Ltd.


Narbel P.A.,Norwegian School of Management | Hansen J.P.,University of Bergen
Renewable and Sustainable Energy Reviews | Year: 2014

This study produces an attempt to estimate the cost of future global energy supplies. The approach chosen to address this concern relies on a comparative static exercise of estimating the cost of three energy scenarios representing different energy futures. The first scenario, the business as usual scenario, predicts the future energy-mix based on the energy plans held by major countries. The second scenario is the renewable energy scenario, where as much of the primary energy supply as possible is replaced by renewable energy by 2050. The cost of the renewable energy generating technologies and their theoretical potential are taken into account in order to create a plausible scenario. The third scenario, the nuclear case, is based on the use of nuclear and renewable energy to replace fossil-fuels by 2050. Endogenous learning rates for each technology are modeled using an innovative approach where learning rates are diminishing overtime. It results from the analysis that going fully renewable would cost between -0.4 and 1.5% of the global cumulated GDP over the period 2009-2050 compared to a business as usual strategy. An extensive use of nuclear power can greatly reduce this gap in costs. © 2014 Elsevier Ltd.


Helle K.B.,University of Bergen
Results and Problems in Cell Differentiation | Year: 2010

Chromogranin A (CgA), chromogranin B (CgB), and secretogranin II (SgII) belong to a family of uniquely acidic secretory proteins in elements of the diffuse neuroendocrine system. These "granins" are characterized by numerous pairs of basic amino acids as potential sites for intra- and extragranular processing. In response to adequate stimuli, the granins are coreleased with neurotransmitters and hormones and appear in the circulation as potential modulators of homeostatic processes. This review is directed towards functional aspects of the secreted CgA, CgB, and SgII and their biologically active sequences. Widely different effects and targets have been reported for granin-derived peptides. So far, the CgA peptides vasostatin-I, pancreastatin, and catestatin, the CgB peptides CgB1-41 and secretolytin, and the SgII peptide secretoneurin are the most likely candidates for granin-derived regulatory peptides. Most of their effects fit into patterns of direct or indirect modulations of major functions, in particular associated with inflammatory conditions. © 2010 Springer-Verlag Berlin Heidelberg.


Van De Vliert E.,University of Groningen | Van De Vliert E.,University of Bergen
Behavioral and Brain Sciences | Year: 2013

Forty-nine commentators have reviewed the theory that needs-based stresses and freedoms are shaped differently in threatening, comforting, and challenging climato-economic habitats. Their commentaries cover the white domain, where the theory does apply (e.g., happiness, collectivism, and democracy), the gray domain, where it may or may not apply (e.g., personality traits and creativity), and the black domain, where it does not apply (e.g., human intelligence and gendered culture). This response article provides clarifications, recommendations, and expectations. Copyright © 2013 Cambridge University Press.


This is a diachronic comparative case study of three successive efforts by Norwegian governments over several decades to move central agencies in Oslo, Norway, to other locations outside the capital region. The key research question is how to explain the unexpected success of the latest governmental relocation program of the 2000s, in view of two previous spectacularly dismal efforts. How was it possible to realize this highly contested policy program against apparently quite adverse odds? We use a modified extended version of the MS framework through three full policy cycles to demonstrate how a remarkably audacious policy entrepreneur in cabinet position employed manipulation strategies within an open policy window to fashion a legislative optimal policy program design by organizing adversely affected stakeholders out of the policy formulation process, thus ensuring its adoption and implementation. © 2016, Springer Science+Business Media New York.


Roy M.S.,University of Bergen | Janal M.N.,New York University
Archives of Ophthalmology | Year: 2010

Objective: To report the association of dietary nutrient intakes in relation to the 6-year progression of diabetic retinopathy (DR) in African American patients with type 1 diabetes mellitus. Methods: African American patients with type 1 diabetes who participated in the baseline and 6-year follow-up examinations as part of the New Jersey 725 study were included. At the baseline examination, a food frequency questionnaire was used to document average daily dietary nutrient intakes. Clinical evaluations at baseline and at the 6-year follow-up also included a structured clinical interview, ocular examination, grading of 7 standard field stereoscopic fundus photographs, and blood pressure measurements. Biological evaluations included blood and urine assays. Nutrient intake data were analyzed using DietSys software and nutrient databases developed by the National Cancer Institute. Results: Among the 469 participants at risk for progression of DR, baseline total caloric intake was significantly associated with 6-year incidence of visionthreateningDR( either proliferativeDRor macular edema) and of severe hard exudates-after adjusting for clinical risk factors for DR progression. Baseline high sodium intake was a significant and independent risk factor for 6-year incidence of macular edema. Conclusions: In African American patients with type 1 diabetes, high caloric and sodium intakes are significant and independent risk factors for progression to severe forms of DR. Dietary recommendations of low caloric and sodium intakes may be beneficial in relation to the development of DR. ©2010 American Medical Association. All rights reserved.


Cygan M.,University of Warsaw | Nederlof J.,University of Bergen | Pilipczuk M.,University of Warsaw | Van Rooij J.M.M.,University Utrecht | Wojtaszczyk J.O.,Google
Proceedings - Annual IEEE Symposium on Foundations of Computer Science, FOCS | Year: 2011

For the vast majority of local problems on graphs of small tree width (where by local we mean that a solution can be verified by checking separately the neighbourhood of each vertex), standard dynamic programming techniques give c tw|V| O(1) time algorithms, where tw is the tree width of the input graph G = (V, E) and c is a constant. On the other hand, for problems with a global requirement (usually connectivity) the best - known algorithms were naive dynamic programming schemes running in at least tw^tw time. We breach this gap by introducing a technique we named Cut&Count that allows to produce c tw|V| O(1) time Monte Carlo algorithms for most connectivity-type problems, including Hamiltonian Path, Steiner Tree, Feedback Vertex Set and Connected Dominating Set. These results have numerous consequences in various fields, like parameterized complexity, exact and approximate algorithms on planar and H-minor-free graphs and exact algorithms on graphs of bounded degree. The constant c in our algorithms is in all cases small, and in several cases we are able to show that improving those constants would cause the Strong Exponential Time Hypothesis to fail. In contrast to the problems aiming to minimize the number of connected components that we solve using Cut&Count as mentioned above, we show that, assuming the Exponential Time Hypothesis, the aforementioned gap cannot be breached for some problems that aim to maximize the number of connected components like Cycle Packing. © 2011 IEEE.


Smedsrud L.H.,University of Bergen | Martin T.,Leibniz Institute of Marine Science
Annals of Glaciology | Year: 2015

The first stage of sea-ice formation is often grease ice, a mixture of sea water and frazil ice crystals. Over time, grease ice typically congeals first to pancake ice floes and then to a solid sea-ice cover. Grease ice is commonly not explicitly simulated in basin-scale sea-ice ocean models, though it affects oceanic heat loss and ice growth and is expected to play a greater role in a more seasonally icecovered Arctic Ocean. We present an approach to simulate the grease-ice layer with, as basic properties, the surface being at the freezing point, a frazil ice volume fraction of 25%, and a negligible change in the surface heat flux compared to open water. The latter governs grease-ice production, and a gradual transition to solid sea ice follows, with ∼50% of the grease ice solidifying within 24 hours. The new parameterization delays lead closing by solid ice formation, enhances oceanic heat loss in fall and winter, and produces a grease-ice layer that is variable in space and time. Results indicate a 10-30% increase in mean winter Arctic Ocean heat loss compared to a standard simulation, with instant lead closing leading to significantly enhanced ice growth.


Kaltenbacher T.,University of Bergen
Ultramicroscopy | Year: 2016

A focused ground state, neutral atom beam, exploiting its de Broglie wavelength by means of atom optics, is used for neutral atom microscopy imaging. Employing Fresnel zone plates as a lens for these beams is a well established microscopy technique. To date, even for favorable beam source conditions a minimal focus spot size of slightly below 1 μm was reached. This limitation is essentially given by the intrinsic spectral purity of the beam in combination with the chromatic aberration of the diffraction based zone plate. Therefore, it is important to enhance the monochromaticity of the beam, enabling a higher spatial resolution, preferably below 100 nm. We propose to increase the monochromaticity of a neutral atom beam by means of a so-called linear monochromator set-up - a Fresnel zone plate in combination with a pinhole aperture - in order to gain more than one order of magnitude in spatial resolution. This configuration is known in X-ray microscopy and has proven to be useful, but has not been applied to neutral atom beams. The main result of this work is optimal design parameters based on models for this linear monochromator set-up followed by a second zone plate for focusing. The optimization was performed for minimizing the focal spot size and maximizing the centre line intensity at the detector position for an atom beam simultaneously. The results presented in this work are for, but not limited to, a neutral helium atom beam. © 2016 Elsevier B.V.


Objective: Western women increasingly delay having children to advance their career, and pregnancy is considered to be riskier among older women. In Norway, this development surprisingly coincides with increased sickness absence among young pregnant women, rather than their older counterparts. This paper tests the hypothesis that young pregnant women have a higher number of sick days because this age group includes a higher proportion of working class women, who are more prone to sickness absence. Design: A zero-inflated Poisson regression was conducted on the Norwegian population registry. Participants: All pregnant employees giving birth in 2004-2008 were included in the study. A total number of 216 541 pregnancies were observed among 180 483 women. Outcome measure: Number of sick days. Results: Although the association between age and number of sick days was U-shaped, pregnant women in their early 20s had a higher number of sick days than those in their mid-40s. This was particularly the case for pregnant women with previous births. In this group, 20-year-olds had 12.6 more sick days than 45-year-olds; this age difference was reduced to 6.3 after control for class. Among women undergoing their first pregnancy, 20-year-olds initially had 1.2 more sick days than 45-year-olds, but control for class altered this age difference. After control for class, 45-year-old first-time pregnant women had 2.9 more sick days than 20-year-olds with corresponding characteristics. Conclusions: The negative association between age and sickness absence was partly due to younger age groups including more working class women, who were more prone to sickness absence. Young pregnant women's needs for job adjustments should not be underestimated.


Helseth L.E.,University of Bergen
Optics Communications | Year: 2010

We study focusing of two and three-dimensional evanescent vector waves, with a particular emphasis on identifying suitable intensity structures for applications in optical data storage. For two-dimensional evanescent waves large transverse spatial wave vectors result in purely circularly polarized evanescent states. We suggest that these may have applications in all-optical data storage through the inverse Faraday effect. On the other hand, for three-dimensional evanescent waves longitudinally polarized modes are observed to give the most tightly focused spot, and this may be utilized to confine light behind a solid immersion lens. © 2009 Elsevier B.V. All rights reserved.


Borthen I.,University of Bergen
Seizure | Year: 2015

Purpose Better knowledge of risk factors for women with epilepsy giving birth. Method Investigating all studies reporting complications in pregnancy and deliveries in women with epilepsy during the last 15 years. Results Studies have observed that women with epilepsy have a higher risk of preeclampsia, gestational hypertension, bleeding in pregnancy, caesarean delivery (CD), excessive bleeding postpartum, preterm birth, and small for gestational age. It has been unclear whether the increased risk of complications is due to the epilepsy per se, the use of antiepileptic drugs (AED), or the combination of both factors. Recent studies strongly indicate an association between AED use, and complications in pregnancy and labour. Conclusion Newer drugs commonly used in treatment of epilepsy are associated with an increased risk of pregnancy complications, as well as complication during labour and delivery.


Harmston N.,Imperial College London | Lenhard B.,Imperial College London | Lenhard B.,University of Bergen
Nucleic Acids Research | Year: 2013

The precise regulation of gene transcription during metazoan development is controlled by a complex system of interactions between transcription factors, histone modifications and modifying enzymes and chromatin conformation. Developments in chromosome conformation capture technologies have revealed that interactions between regions of chromatin are pervasive and highly cell-type specific. The movement of enhancers and promoters in and out of higher-order chromatin structures within the nucleus are associated with changes in expression and histone modifications. However, the factors responsible for mediating these changes and determining enhancer:promoter specificity are still not completely known. In this review, we summarize what is known about the patterns of epigenetic and chromatin features characteristic of elements involved in long-range interactions. In addition, we review the insights into both local and global patterns of chromatin interactions that have been revealed by the latest experimental and computational methods. © 2013 The Author(s).


Kvamme B.,University of Bergen
Journal of Chemical and Engineering Data | Year: 2016

The huge resources of energy in the form of natural gas hydrates are widely distributed worldwide in permafrost sediments as well as in offshore sediments. A novel technology for combined production of these resources and safe long terms storage of carbon dioxide is based on the injection of carbon dioxide injection into in situ methane hydrate filled sediments. This will lead to an exchange of the in situ methane hydrate over to carbon dioxide dominated hydrate and a simultaneous release of methane gas. Recent theoretical and experimental results indicate that the conversion from natural gas hydrate to carbon dioxide hydrate and mixed carbon dioxide/methane hydrate follows two primary mechanisms. Direct solid state transformation is possible but very slow. The dominating mechanism involves formation of a new hydrate from injected carbon dioxide and associated dissociation of the in situ natural gas hydrate by the released heat. Nitrogen is frequently added in order to increase gas permeability and to reduce blocking due to new hydrate formation. In this work we examine the thermodynamic limitations of adding nitrogen. On the basis of state of the art thermodynamic analysis it is concluded that substantial amounts of nitrogen in carbon dioxide will slow down the conversion dramatically. © 2016 American Chemical Society.


Education is presumed to play a decisive role in decreasing fertility rates. This article is about the role of education and other factors in fertility decline in the context of current Ethiopian policies on population and sustainable development, based on an ethnographic study of women's agency and girls' pursuit of education in one semi-urban and one rural area in north-western Tigray, in northern Ethiopia. Long-term environmental insecurity and scarcity of arable land for the younger generation in this area serve as important background. Another central issue in the study was the religious conditioning of women's choices, which stood out most clearly in the case of contraceptive use. The research consisted of in-depth, semi-structured interviews in 2008 with 25 purposively selected women from three generations, based on their life histories, linked with participatory observation and extended informal dialogue with women at different points during 2008-12. A smaller household survey with 170 women and a task-based, education survey with 200 female and male students were also conducted in 2009. In those cases where women's contestations of the authority of the Orthodox Christian priests concurred with current Ethiopian policies on fertility decline, this was based on what women defined as their own authority in reproductive matters linked with flexible adaptation to their life-situations. © 2014 Reproductive Health Matters.


Bollig G.,Palliative Medicine and Pain Therapy | Bollig G.,University of Bergen
Paediatric Anaesthesia | Year: 2013

McArdles disease (glycogen storage disease type v) is a rare condition in which energy-metabolism in the muscle is hampered. A case report is presented and the possible risk for perioperative complications including malignant hyperthermia is discussed. A checklist for the anesthesiological management of patients with McArdles disease is provided. A short overview of anesthesiological challenges and perioperative complications of other glycogen storage diseases is given. © 2013 John Wiley & Sons Ltd.


Karlsen T.H.,University of Oslo | Karlsen T.H.,University of Bergen | Boberg K.M.,University of Oslo
Journal of Hepatology | Year: 2013

Primary sclerosing cholangitis (PSC) remains one of the most challenging conditions of clinical hepatology. There has been a steady growth in research to overcome this fact and the present review aims at summarizing the most recently published literature. The main emphasis will be put on the link of recent pathogenetic insights to clinical characteristics and patient management. With regard to pathogenesis, there is no consensus yet as to whether immune mediated injury or factors related to bile acid physiology are the most important. It also remains to be clarified whether PSC is a mixed bag of various secondary etiologies yet to be defined, or a disease entity predominantly represented by sclerosing cholangitis in the context of inflammatory bowel disease. Most important, there is no available medical therapy with proven influence on clinical end points, and timing of liver transplantation and patient follow-up are challenging due to the unpredictable and high risk of cholangiocarcinoma. © 2013 European Association for the Study of the Liver.


Chera S.,University of Bergen | Herrera P.L.,University of Geneva
Current Opinion in Genetics and Development | Year: 2016

The impaired ability to produce or respond to insulin, a hormone synthetized by the pancreatic β-cells, leads to diabetes. There is an excruciating need of finding new approaches to protect or restore these cells once they are lost. Replacement and ex vivo directed reprogramming methods have an undeniable therapeutic potential, yet they exhibit crucial flaws. The in vivo conversion of adult cells to functional insulin-producing cells is a promising alternative for regenerative treatments in diabetes. The stunning natural transdifferentiation potential of the adult endocrine pancreas was recently uncovered. Modulating molecular targets involved in β-cell fate maintenance or in general differentiation mechanisms can further potentiate this intrinsic cell plasticity, which leads to insulin production reconstitution. © 2016 Elsevier Ltd.


Samdal O.,University of Bergen | Rowling L.,University of Sydney
Health Education | Year: 2011

Purpose: Efforts to create a scientific base for the health-promoting school approach have so far not articulated a clear "Science of Delivery". There is thus a need for systematic identification of clearly operationalised implementation components. To address a next step in the refinement of the health-promoting schools' work, this paper sets out to delineate implementation components of health-promoting schools and to identify their mechanisms. Design/methodology/approach: The implementation components were identified through a narrative synthesis of documents describing implementation of health-promoting school approaches. Studies were included if they were published between 1995 and June 2010 and could be identified in publicly accessible peer-reviewed articles and grey literature, published in English. Eight sources were extracted, representing reports from all continents with the exception of Africa. Findings: Eight components were identified: preparing and planning for school development; policy and institutional anchoring; professional development and learning; leadership and management practices; relational and organisational support context; student participation; partnerships and networking; and sustainability. Practical implications: The components provide a practical tool/guide for schools to use in the implementation of health-promoting schools. In a parallel paper theoretically and empirically based practice guidelines for the actual implementation of the components are articulated ("Filling the black box of implementation for health-promoting schools", this issue). Originality/value: The identification of specified theory-driven implementation components for health-promoting schools aims will help practitioners to understand the function of each component, so they can execute them with fidelity and thus contribute to rigorous implementation of the health-promoting school initiative. © Emerald Group Publishing Limited.


Incomplete combustion of carbon based materials produces fine, carbon rich particles. Controlled manufacturing of very pure carbon nanoparticles (Carbon Black) can be achieved by, for example, thermal decomposition of gaseous precursors like acetylene and methane. Molecular dynamics simulations of hydrocarbon growth after non-catalyzed thermal decomposition of methane were carried out in order to understand the impact of the thermal decomposition reaction of methane on the formation of large hydrocarbon molecules. A reactive force field (ReaxFF) was employed to model the interactions of the involved hydrocarbons. The decomposition of 150 methane molecules was investigated at different system temperatures and system densities. Formation of molecular hydrogen, a broad range of hydrocarbons and carbon dimers from decomposed methane was observed above a temperature of 2500 K. The basic reactions are in agreement with existing models of thermal decomposition of methane. An increasing variety of hydrocarbons is observed with increasing temperature. The largest molecules formed within 1 ns of simulation time at 3500 K contain enough carbon atoms to form ring structures. Ring formation is observed in one case. © the Owner Societies 2010.


Gjerstad M.D.,University of Stavanger | Tysnes O.B.,University of Bergen | Larsen J.P.,University of Stavanger
Neurology | Year: 2011

Objective: This study explores the risk and correlates of leg restlessness in drug-naive patients with Parkinson disease (PD) as compared to control subjects matched for age and gender. Methods: A total of 200 drug-naive patients with early, unmedicated PD derived from a population-based incident cohort and 173 age- and gender-matched control subjects were assessed for leg restlessness by structured interviews, clinical examination, and blood samples. All subjects were Caucasian. Restless legs syndrome (RLS) was diagnosed according to the essential diagnostic criteria. Results: More patients (81 of 200, 40.5%) than controls (31 of 173, 17.9%) reported leg restlessness (p < 0.001). Thirty-one (15.5%) of these patients with PD and 16 (9.2%) control subjects met RLS criteria (p - 0.07). A total of 21 (12.5%) patients and 12 (6.9%) controls with RLS remained after the exclusion of potential RLS mimics and 26 patients vs 10 control subjects with leg motor restlessness (LMR), leading to a relative risk for RLS of 1.76 (95% confidence interval [CI] 0.90-3.43, p - 0.089) and 2.84 for LMR (95% CI 1.43-5.61, p - 0.001) in PD. Except for increased sleep disturbances in patients with RLS and increased Montgomery and Åsberg Depression Rating Scale scores for patients with RLS or LMR there were no other major differences in relevant blood tests, motor or cognitive function between PD with and without RLS or LMR. Conclusion: LMR and not RLS occurs with a near 3-fold higher risk as compared to controls in early PD. The findings underline a need for more accurate assessments of RLS in PD and support the notion that RLS and PD are different entities. Copyright © 2011 by AAN Enterprises, Inc.


Gilbertson S.,University of Bergen
International Journal of Qualitative Studies on Health and Well-being | Year: 2013

This article presents and discusses a long-term repeated-immersion research process that explores meaning allocated to an episode of 50 seconds of music improvisation in early neurosurgical rehabilitation by a teenage boy with severe traumatic brain injury and his music therapist. The process began with the original therapy session in August 1994 and extends to the current time of writing in 2013. A diverse selection of qualitative research methods were used during a repeated immersion and engagement with the selected episodes. The multiple methods used in this enquiry include therapeutic narrative analysis and musicological and video analysis during my doctoral research between 2002 and 2004, arts-based research in 2008 using expressive writing, and arts-based research in 2012 based on the creation of a body cast of my right hand as I used it to play the first note of my music improvising in the original therapy episode, which is accompanied by reflective journaling. The casting of my hand was done to explore and reconsider the role of my own body as an embodied and integral, but originally hidden, part of the therapy process. Put together, these investigations explore the potential meanings of the episode of music improvisation in therapy in an innovative and imaginative way. However, this article does not aim at this stage to present a model or theory for neurorehabilitation but offers an example of how a combination of diverse qualitative methods over an extended period of time can be instrumental in gaining innovative and rich insights into initially hidden perspectives on health, well-being, and human relating. © 2013 S. Gilbertson.


Aavatsmark I.,University of Bergen
Computational Geosciences | Year: 2016

Peaceman’s equivalent well-cell radius for 2D Cartesian grids has been generalized to 2D uniform Voronoi grids consisting of stretched hexagons in an isotropic medium. An analytical expression for the equivalent well-cell radius for infinitely fine grids is derived. The derivation is performed by comparison of analytical and numerical solution for boundary value problems with one or two wells. Since the well-cell radius varies slowly with the grid fineness, the found formula can be considered representative for all grid sizes. © 2016 Springer International Publishing Switzerland


Rowling L.,University of Sydney | Samdal O.,University of Bergen
Health Education | Year: 2011

Purpose: Achieving organisational learning and greater specificity for implementation action for health-promoting schools requires detailed understanding of the necessary components. They include: preparing and planning for school development, policy and institutional anchoring, professional development and learning, leadership and management practices, relational and organisational context, student participation, partnerships and networking, and sustainability. This paper seeks to elaborate a theoretically based rationale for how these eight components of implementation that needs to be put into action. Design/methodology/approach: Building on the narrative synthesis in the complementary paper ("Theoretical base for implementation components of health-promoting schools", this issue), examples drawn from empirical research and evaluation reports in the field of health-promoting schools are used to operationalise the function of the components. Findings: This elaboration anchors specific implementation actions within their own theoretical and empirical base, a significant advance on previous guidelines. The eight components have been articulated separately. However, in practice they operate interdependently. Context and culture issues also need to be accommodated. Practical implications: The level of specificity provided in this paper has the potential to enhance school staff professional learning, as it fulfils one of the characteristics for successful school-based education, namely practical, detailed implementation and enough flexibility, allowing shaping to suit specific contexts. Originality/value: The identification of this knowledge base should enable practitioners to develop an in-depth understanding of the operational functioning of existing guidelines, thereby enhancing their practice. The specificity provided holds promise to enhance the science base and quality of implementation. © Emerald Group Publishing Limited.


Nielsen M.B.,National Institute of Occupational Health | Nielsen M.B.,University of Bergen | Knardahl S.,National Institute of Occupational Health
Scandinavian Journal of Psychology | Year: 2014

The aims of this article are: (1) to explore patterns (clusters) of coping strategies; (2) to examine the stability of individual coping strategies and patterns of coping over time; and (3) to establish long term associations between coping and psychological distress. Coping strategies were assessed with the Brief Cope questionnaire, whereas psychological distress was measured with the ten-item version of the Hopkins Symptom Checklist, in a two-year prospective sample comprising 3,738 employees. Based on TwoStep cluster analysis of the Brief Cope, three different coping patterns were identified: low coping, engagement coping, and disengagement coping. Analyses of long-term stability indicated malleable properties for the individual coping strategies as well as the three clusters. Disengagement coping strategies in the form of self-blame and self-distraction were most strongly associated with distress at follow-up, whereas baseline distress was related to increased use of these strategies two years later. Coping patterns at baseline had no main effects on later levels of distress, but levels of distress at baseline predicted subsequent use of engagement and disengagement coping patterns. The finding that specific coping strategies are malleable suggests that it is possible to modify and develop dysfunctional strategies. The associations between disengagement coping strategies and distress indicate that this kind of coping is especially problematic with regard to mental health problems. A main contribution of this study is that it establishes cluster analytic techniques as beneficial in the assessment of coping. © 2014 Scandinavian Psychological Associations and John Wiley & Sons Ltd.


Tveit T.O.,University of Bergen
Acta Anaesthesiologica Scandinavica | Year: 2013

Background: To collect updated information about pharmacological labour analgesia in Norway, especially systemic opioids and epidural. Evaluation of efficacy and safety with remifentanil intravenous patient-controlled analgesia (IVPCA) for pain relief during labour. To compare remifentanil IVPCA with epidural analgesia (EDA) regarding efficacy and safety during labour. Methods: In paper I, two national surveys identified Norwegian labour analgesia methods and changes during the study period (2005-2008). Paper II is a prospective, observational study of analgesic efficacy and safety with remifentanil IVPCA. Paper III is a prospective, randomized controlled trial comparing remifentanil IVPCA with EDA regarding analgesic efficacy and safety. Results: The surveys in paper I found the frequency of EDA in Norwegian hospitals to be increasing, but still low (25.9%) compared with other western countries. Nitrous oxide and traditional systemic opioids, like pethidine, were frequently used. In paper II, remifentanil IVPCA was found to give satisfactory labour analgesia in more than 90% of the parturients with an average maximal pain reduction of 60%. Maternal oxygen desaturation and sedation were acceptable, and neonatal data reassuring. In paper III, a randomized controlled trial found remifentanil IVPCA and EDA to be comparable both regarding analgesic efficacy (pain reduction; Fig.) and maternal satisfaction. Remifentanil IVPCA produced more maternal sedation and oxygen desaturation; neonatal outcome was reassuring in both groups. Reduction in pain score [visualanaloguescale (VAS)] during labour analgesia with patient-controlled intravenous remifentanil and continuous epidural infusion with ropivacaine and fentanyl. Conclusion: The frequency of epidural labour analgesia in Norway has increased, but is still relatively low. Nitrous oxide and traditional systemic opioids are frequently used. The clinical practice seems conservative; newer short-acting opioids are seldom used for systemic labour analgesia. The studies on remifentanil IVPCA revealed adequate pain relief, high maternal satisfaction, and no serious neonatal side effects. There were no differences in analgesic efficacy, maternal satisfaction, and neonatal outcome when comparing remifentanil IVPCA with EDA. However, remifentanil caused maternal sedation and oxygen desaturation. We recommend the use of IVPCA remifentanil as labour analgesia instead of traditional opioids as pethidine and morphine when EDA is not an option. The presence of skilled personnel and close monitoring is mandatory. © 2013 The Acta Anaesthesiologica Scandinavica Foundation.


Displays of latent variable regression models in variable and object space are provided to reveal model parameters useful for interpretation and to reveal the most influential x-variables with respect to the predicted response. Although the target projected (TP) component obtained from a standard partial least square, or equivalently, the predictive component from orthogonal partial least squares (OPLS) or partial least squares + similarity transform (PLS +ST) is maximally co-varying with the response, the corresponding loadings are not necessarily the best choice for model interpretation and disclosure of the most important variables with respect to explaining the response. Selectivity ratio plot represents a bridge from co-variance-based TP loadings to correlation-like localized information suitable for interpretation. Copyright © 2010 John Wiley & Sons, Ltd.


Background:Around 50% of primary melanomas harbour BRAF mutations, but their prognostic impact has not been clear. Recently, a BRAF-V600E mutation-specific antibody has become available for immunohistochemistry. Here, we investigated for the first time the prognostic impact of BRAF-V600E protein expression in primary melanoma.Methods:In a patient series of 248 nodular melanomas, BRAF-V600E and total BRAF expression were assessed by immunohistochemistry using tissue microarray sections of paraffin-embedded archival tissue. Mutation status was assessed by real-time PCR in cases with sufficient tumour tissue (n=191).Results:Positive BRAF-V600E expression was present in 86 (35%) of the cases, and was significantly associated with increased tumour thickness, presence of tumour ulceration and reduced survival. Further, BRAF-V600E expression was an independent prognostic factor by multivariate analysis, whereas BRAF mutation status was not significant. There was 88% concordance between BRAF-V600E expression and mutation status.Conclusions:Our findings indicate that BRAF-V600E expression is a novel prognostic marker in primary melanoma.British Journal of Cancer advance online publication, 25 February 2016; doi:10.1038/bjc.2016.44 www.bjcancer.com. © 2016 Cancer Research UK


Bae E.,University of Bergen | Shi J.,Nanyang Technological University | Tai X.-C.,Nanyang Technological University
IEEE Transactions on Image Processing | Year: 2011

Minimization of total variation (TV) is a well-known method for image denoising. Recently, the relationship between TV minimization problems and binary MRF models has been much explored. This has resulted in some very efficient combinatorial optimization algorithms for the TV minimization problem in the discrete setting via graph cuts. To overcome limitations, such as staircasing effects, of the relatively simple TV model, variational models based upon higher order derivatives have been proposed. The Euler's elastica model is one such higher order model of central importance, which minimizes the curvature of all level lines in the image. Traditional numerical methods for minimizing the energy in such higher order models are complicated and computationally complex. In this paper, we will present an efficient minimization algorithm based upon graph cuts for minimizing the energy in the Euler's elastica model, by simplifying the problem to that of solving a sequence of easy graph representable problems. This sequence has connections to the gradient flow of the energy function, and converges to a minimum point. The numerical experiments show that our new approach is more effective in maintaining smooth visual results while preserving sharp features better than TV models. © 2006 IEEE.


Jansen B.M.P.,University of Bergen
Algorithmica | Year: 2015

We investigate whether an n-vertex instance (G, k) of Treewidth, asking whether the graph G has treewidth at most k, can efficiently be made sparse without changing its answer. By giving a special form of OR-cross-composition, we prove that this is unlikely: if there is an ∈ > 0 and a polynomial-time algorithm that reduces n-vertex Treewidth instances to equivalent instances, of an arbitrary problem, with O(n2-∈) bits, then NP ⊆ coNP/poly and the polynomial hierarchy collapses to its third level. Our sparsification lower bound has implications for structural parameterizations of Treewidth: parameterizations by measures ℓ that do not exceed the number of vertices cannot have kernels with O(ℓ2-∈) bits for any ∈ > 0, unless NP ⊆ coNP/poly. Motivated by the question of determining the optimal kernel size for Treewidth parameterized by the size of a vertex cover X, we improve the O(ǀXǀ3)-vertex kernel from Bodlaender et al. (SIDMA 2013) to a kernel with O(ǀXǀ2) vertices. Our improved kernel is based on the novel notion of treewidth-invariant set. We use the q-expansion lemma of Fomin et al. (STACS 2011) to find such sets efficiently in graphs whose order is superquadratic in their vertex cover number. We believe that our new reduction rule will be useful in practice. © 2014, Springer Science+Business Media New York.


Mells G.F.,University of Cambridge | Kaser A.,University of Cambridge | Karlsen T.H.,University of Oslo | Karlsen T.H.,University of Bergen
Journal of Autoimmunity | Year: 2013

Autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) are complex disorders, resulting from the interaction of genetic and environmental factors. For many years, investigators have attempted to delineate the genetic architecture of these conditions, aiming to elucidate disease pathogenesis and identify molecular targets for pharmacotherapy. Early genetic studies consisted of HLA association studies and non-HLA candidate gene association studies, designed to identify association with selected HLA or non-HLA loci. HLA association studies identified HLA risk loci that are now well-established. Non-HLA candidate gene studies were less fruitful because they were mostly underpowered to detect modest effects and were frequently designed to investigate one or two functional polymorphisms, meaning that gene coverage was poor. Furthermore, weak associations detected in one small cohort were often never validated. If replication studies were undertaken, the results were often conflicting. More recently, a series of genome-wide association studies (GWAS) and related study designs have evaluated the impact of common genetic variants (frequency >5% in the general population) across the entire genome. These studies have identified several non-HLA risk loci for autoimmune liver disease. The majority of risk loci detected are similar to those of non-hepatic immune-mediated diseases, suggesting that outcomes from GWAS and related genetic studies reflect broad phenotypic themes rather than traditional clinical conditions. The specific genetic basis of these PBC and PSC associated inflammatory themes as determined by GWAS is described and discussed in the context of interacting genetic and non-genetic (including environmental) factors. © 2013 Elsevier Ltd.


Mossler K.,University of Bergen
Cochrane database of systematic reviews (Online) | Year: 2011

Music therapy is a therapeutic method that uses musical interaction as a means of communication and expression. The aim of the therapy is to help people with serious mental disorders to develop relationships and to address issues they may not be able to using words alone. To review the effects of music therapy, or music therapy added to standard care, compared with 'placebo' therapy, standard care or no treatment for people with serious mental disorders such as schizophrenia. We searched the Cochrane Schizophrenia Group Trials Register (December 2010) and supplemented this by contacting relevant study authors, handsearching of music therapy journals and manual searches of reference lists. All randomised controlled trials (RCTs) that compared music therapy with standard care, placebo therapy, or no treatment. Studies were reliably selected, quality assessed and data extracted. We excluded data where more than 30% of participants in any group were lost to follow-up. We synthesised non-skewed continuous endpoint data from valid scales using a standardised mean difference (SMD). If statistical heterogeneity was found, we examined treatment 'dosage' and treatment approach as possible sources of heterogeneity. We included eight studies (total 483 participants). These examined effects of music therapy over the short- to medium-term (one to four months), with treatment 'dosage' varying from seven to 78 sessions. Music therapy added to standard care was superior to standard care for global state (medium-term, 1 RCT, n = 72, RR 0.10 95% CI 0.03 to 0.31, NNT 2 95% CI 1.2 to 2.2). Continuous data identified good effects on negative symptoms (4 RCTs, n = 240, SMD average endpoint Scale for the Assessment of Negative Symptoms (SANS) -0.74 95% CI -1.00 to -0.47); general mental state (1 RCT, n = 69, SMD average endpoint Positive and Negative Symptoms Scale (PANSS) -0.36 95% CI -0.85 to 0.12; 2 RCTs, n=100, SMD average endpoint Brief Psychiatric Rating Scale (BPRS) -0.73 95% CI -1.16 to -0.31); depression (2 RCTs, n = 90, SMD average endpoint Self-Rating Depression Scale (SDS) -0.63 95% CI -1.06 to -0.21; 1 RCT, n = 30, SMD average endpoint Hamilton Depression Scale (Ham-D) -0.52 95% CI -1.25 to -0.21 ); and anxiety (1 RCT, n = 60, SMD average endpoint SAS -0.61 95% CI -1.13 to -0.09). Positive effects were also found for social functioning (1 RCT, n = 70, SMD average endpoint Social Disability Schedule for Inpatients (SDSI) score -0.78 95% CI -1.27 to -0.28). Furthermore, some aspects of cognitive functioning and behaviour seem to develop positively through music therapy. Effects, however, were inconsistent across studies and depended on the number of music therapy sessions as well as the quality of the music therapy provided. Music therapy as an addition to standard care helps people with schizophrenia to improve their global state, mental state (including negative symptoms) and social functioning if a sufficient number of music therapy sessions are provided by qualified music therapists. Further research should especially address the long-term effects of music therapy, dose-response relationships, as well as the relevance of outcomes measures in relation to music therapy.


The Norwegian Mother and Child Cohort Study (MoBa) is a valuable resource for the study of the effects of maternal alcohol consumption. MoBa’s strengths include a population-based sample of over 107,000 pregnancies, concurrent and retrospective assessment of maternal prenatal and postnatal alcohol consumption, and prospective follow-up for pregnancy and child outcomes. Direct questions were asked on the frequency, dose and timing of maternal alcohol consumption. Screening tools including the T-ACE and partial Rutgers Alcohol Problem Index were used to identify women at risk for drinking during pregnancy. Comprehensive information on potential confounders was collected including maternal medical history, reproductive history, smoking, and other substance use. The detailed alcohol data allow the differentiation between non-binge and binge-level drinking, important for studying different thresholds of exposure. The availability of maternal and infant DNA enables the study of genetic differences in alcohol metabolism. Besides conventional analyses, sibship studies of differentially exposed siblings can be conducted among the offspring of over 15,000 women who participated in the study for more than one pregnancy. Although there are low levels of social disadvantage in Norway (poverty increases the risk of harms from prenatal drinking), binge drinking is a common pattern of consumption and previous studies found that drinking alcohol during pregnancy is not uncommon. Here, I provide a brief review of prenatal alcohol literature and measurement issues, describe MoBa alcohol variables, and discuss how MoBa can contribute to maternal alcohol research within the context of Norway. © 2014, Norwegian Epidemiological Society. All rights reserved.


Badcock J.C.,University of Western Australia | Badcock J.C.,Clinical Research Center | Hugdahl K.,University of Bergen
Frontiers in Human Neuroscience | Year: 2014

The National Institute of Mental Health initiative called the Research Domain Criteria (RDoC) project aims to provide a new approach to understanding mental illness grounded in the fundamental domains of human behavior and psychological functioning. To this end the RDoC framework encourages researchers and clinicians to think outside the [diagnostic] box, by studying symptoms, behaviors or biomarkers that cut across traditional mental illness categories. In this article we examine and discuss how the RDoC framework can improve our understanding of psychopathology by zeroing in on hallucinations- now widely recognized as a symptom that occurs in a range of clinical and non-clinical groups. We focus on a single domain of functioning-namely cognitive [inhibitory] control-and assimilate key findings structured around the basic RDoC "units of analysis," which span the range from observable behavior to molecular genetics. Our synthesis and critique of the literature provides a deeper understanding of the mechanisms involved in the emergence of auditory hallucinations, linked to the individual dynamics of inhibitory development before and after puberty; favors separate developmental trajectories for clinical and non-clinical hallucinations; yields new insights into co-occurring emotional and behavioral problems; and suggests some novel avenues for treatment.


Dilek Y.,Miami University Ohio | Dilek Y.,Hubei University | Furnes H.,University of Bergen
Bulletin of the Geological Society of America | Year: 2011

Ophiolites, and discussions on their origin and significance in Earth's history, have been instrumental in the formulation, testing, and establishment of hypotheses and theories in earth sciences. The definition, tectonic origin, and emplacement mechanisms of ophiolites have been the subject of a dynamic and continually evolving concept since the nineteenth century. Here, we present a review of these ideas as well as a new classification of ophiolites, incorporating the diversity in their structural architecture and geochemical signatures that results from variations in petrological, geochemical, and tectonic processes during formation in different geodynamic settings. We define ophiolites as suites of temporally and spatially associated ultramafic to felsic rocks related to separate melting episodes and processes of magmatic differentiation in particular tectonic environments. Their geochemical characteristics, internal structure, and thickness vary with spreading rate, proximity to plumes or trenches, mantle temperature, mantle fertility, and the availability of fluids. Subduction-related ophiolites include suprasubduction-zone and volcanic-arc types, the evolution of which is governed by slab dehydration and accompanying metasomatism of the mantle, melting of the subducting sediments, and repeated episodes of partial melting of metasomatized peridotites. Subduction-unrelated ophiolites include continental-margin, mid-ocean-ridge (plume-proximal, plume-distal, and trench-distal), and plume-type (plume-proximal ridge and oceanic plateau) ophiolites that generally have mid-ocean-ridge basalt (MORB) compositions. Subduction-related lithosphere and ophiolites develop during the closure of ocean basins, whereas subduction-unrelated types evolve during rift drift and seafloor spreading. The peak times of ophiolite genesis and emplacement in Earth history coincided with collisional events leading to the construction of supercontinents, continental breakup, and plume-related supermagmatic events. Geochemical and tectonic fingerprinting of Phanerozoic ophiolites within the framework of this new ophiolite classification is an effective tool for identification of the geodynamic settings of oceanic crust formation in Earth history, and it can be extended into Precambrian greenstone belts in order to investigate the ways in which oceanic crust formed in the Archean. © 2011 Geological Society of America.


Berezovsky I.N.,University of Bergen
Physical Biology | Year: 2011

Intermolecular interactions became an inherent part of the structure-function paradigm. Therefore, the generalized concept of protein stability and interactions should consider the balance of stabilizing forces working in different types of intermolecular interactions. We consider here two 'extremes' of protein interactions, viral protein with high intrinsic disorder and hyperthermostable protein complexes. Intermolecular interactions provide folding upon binding as a part of function in the viral case, while they secure and stabilize specific native interfaces as a prerequisite for function in hyperthermostable complexes. We propose a generalized concept of protein stability and interactions, which includes intermolecular interactions comprising distinct combinations of stabilizing forces depending on the types of interacting partners. © 2011 IOP Publishing Ltd.


De Schepper S.,University of Bergen | Gibbard P.L.,University of Cambridge | Salzmann U.,Northumbria University | Ehlers J.,Hellberg 2a
Earth-Science Reviews | Year: 2014

The Pliocene climate is globally warm and characterised by high atmospheric carbon dioxide concentrations, yet the terrestrial and marine scientific communities have gathered considerable evidence for substantial glaciation events in both the Northern and Southern Hemisphere prior to the Quaternary. Evidence on land is fragmentary, but marine records of glaciation present a more complete history of Pliocene glaciation. Here we present a global compilation of the terrestrial and marine glacial evidence for the Pliocene and demonstrate four glaciation events that can be identified in the Southern and/or Northern Hemisphere prior to the latest Pliocene intensification of Northern Hemisphere glaciation. There are two globally recognisable glacial events in the early Pliocene (c. 4.9-4.8. Ma and c. 4.0. Ma), one event around the early/late Pliocene transition (c. 3.6. Ma), and one event during Marine Isotope Stage M2 (c. 3.3. Ma). Long-term climate cooling, decreasing carbon dioxide concentrations in the atmosphere and high climate sensitivity in the Pliocene probably facilitated each glaciation event, however the mechanisms behind the early Pliocene glacial events are unclear. The global glaciation at c. 3.3. Ma may be caused by changes in ocean gateways, whereas the decline in carbon dioxide concentrations is important for the latest Pliocene intensification of Northern Hemisphere glaciation. © 2014 Elsevier B.V.


Long time series of offshore meteorological measurements in the lower marine atmospheric boundary layer show dynamical regimes and variability that are forced partly by interaction with the underlying sea surface and partly by the passage of cloud systems overhead. At low wind speeds, the dynamics and stability structure of the surface layer depend mainly on the air-sea temperature difference and measured wind speed at a standard height. The physical processes are mostly understood and quantified through Monin-Obukhov (MO) similarity theory. At high wind speeds, different dynamical regimes become dominant, with breaking waves, sea spray, and organized boundary layer convection cells contributing to observed effects. Data from offshore meteorological monitoring sites typically show different behavior and regime shifts depending on the local winds and synoptic conditions. However, the regular methods to interpret time series through spectral analysis only give a partial view of the dynamics in the atmospheric boundary layer. Wind speed and the air-sea temperature difference are important factors that characterize the dynamics of the lower atmospheric boundary layer, and they provide a dynamic and thermodynamic constraint to frame observed processes, especially at high wind speeds. Early studies of long time series of automated offshore meteorological data recognized the value of the joint probability distribution on axes of wind speed and air-sea temperature difference to summarize large segments of the data. The approach can be extended to probe the marine atmospheric boundary layer conditions that are important for the loading of offshore wind turbines: turbulence intensity and wave conditions. The increasing numbers of offshore meteorological masts that are associated with the offshore wind industry are amenable to a similar approach to understand the main characteristics of the boundary layer. In this case, the diagnostic figure provides a method to 'fingerprint' the atmospheric conditions at an offshore site. © 2014 The Authors.


Vovchenko V.,Taras Shevchenko National University | Anchishkin D.,NASU Bogolyubov Institute for Theoretical Physics | Csernai L.P.,University of Bergen
Physical Review C - Nuclear Physics | Year: 2013

A model for computing the probability density of event-by-event participant center-of-mass rapidity yc.m. is presented. The evaluations of the yc.m. distribution are performed for different collision energies and different centralities. We show that for certain conditions the rapidity distribution is described by a Gaussian with a variance determined mostly by the collision centrality. It is found that the width of the yc.m. distribution increases strongly for more peripheral collisions, while it depends weakly on the collision energy. Other theoretical estimates of rapidity distribution are presented and questions of interaction and separation between spectators and participants are discussed. © 2013 American Physical Society.


This study examined the influence of safety climate and psychosocial work environment on the reported fatigue of seafarers working in the offshore oil and gas re-supply industry (n = 402). We found that seafarers who reported high psychological demands and perceived the organisational-level safety climate negatively,reported significantly more mental fatigue, physical fatigue, and lack of energy. In addition, seafarers who reported having high levels of job control reported being significantly less mentally fatigued. We also found some combined effects of safety climate and shift arrangement. Organisational-level safety climate did not influence the levels of physical fatigue in seafarers working on the night shift. On the contrary, seafarers working during the days reported to be more physically fatigued when they perceived the organisational-level climate to be negative compared with the positive. The opposite effect was found for group-level safety climate: seafarers working during the nights reported to be more physically fatigued when they perceived the group-level climate to be negative compared with the positive. The results from this study point to the importance of taking into consideration aspects of the psychosocial work environment and safety climate,and their potential impact on fatigue and safety in the maritime organisations.


Attitude change approaches are common in the prevention of intimate partner violence (IPV) among adolescents. This study examined associations between perpetration or victimization and attitudes toward IPV with data from a longitudinal randomized controlled trial (RCT) of an HIV prevention intervention among school students in three sites in South Africa and Tanzania. Data analyses were confined to students from the control group only, and to those with experience with romantic relationships. Boys and those more involved with violence reported more violence-supportive attitudes. For Cape Town (and to some extent Mankweng), the results of prospective prediction are consistent with the notion of a bidirectional attitudes-behavior interrelationship. For Dar es Salaam attitudes predicted behavior prospectively; however, prediction in the opposite direction was not confirmed. These results indicate that attitude change strategies may be useful complementary to structural approaches also in global South settings, although their effectiveness may vary.


Helseth L.E.,University of Bergen
European Journal of Physics | Year: 2011

We propose a simple and fascinating experiment for studying diffusion in gels using a pH-sensitive dye. By doping agar with methyl red, we obtain a gel which rapidly reacts to changes in pH by changing its absorption spectrum. The pH gradients can be followed using a digital camera, and we demonstrate here that the pH-sensitive colour changes can be used to print colour patterns in the gel which due to diffusion of ions may disappear entirely. © 2011 IOP Publishing Ltd.


Tollanes M.C.,University of Bergen
Orphanet journal of rare diseases | Year: 2012

The porphyrias are a heterogeneous group of rare metabolic diseases. The full spectrum of porphyria diagnostics is usually performed by specialized porphyria laboratories or centres. The European Porphyria Initiative (EPI), a collaborative network of porphyria centres formed in 2001, evolved in 2007 into the European Porphyria Network (EPNET), where participating centres are required to adhere to agreed quality criteria. The aim of this study was to examine the state and distribution of porphyria diagnostic services in 2009 and to explore potential effects of increased international collaboration in the field of these rare diseases in the period 2006-2009. Data on laboratory, diagnostic and clinical activities and services reported to EPI/EPNET in yearly activity reports during 2006 through 2009 were compared between reporting centres, and possible time trends explored. Thirty-five porphyria centres from 22 countries, five of which were non-European associate EPNET members, filed one or more activity reports to EPI/EPNET during the study period. Large variations between centres were observed in the analytical repertoire offered, numbers of analyses performed and type and number of staff engaged. The proportion of centres fulfilling the minimum criteria set by EPNET to be classified as a specialist porphyria centre increased from 80% to 94% during the study period. Porphyria services are unevenly distributed, and some areas are probably still lacking in specialized porphyria services altogether. However, improvements in the quality of diagnostic services provided by porphyria centres participating in EPI/EPNET were observed during 2006 through 2009.


Olsen K.A.,University of Bergen | Malizia A.,Charles III University of Madrid
Communications of the ACM | Year: 2012

Increasing the visibility and access to underlying file structure on consumer devices can vastly improve the user experience.


Mangel M.,University of California at Santa Cruz | Mangel M.,University of Bergen
Bulletin of Mathematical Biology | Year: 2015

I describe how stochastic dynamic programming (SDP), a method for stochastic optimization that evolved from the work of Hamilton and Jacobi on variational problems, allows us to connect the physiological state of organisms, the environment in which they live, and how evolution by natural selection acts on trade-offs that all organisms face. I first derive the two canonical equations of SDP. These are valuable because although they apply to no system in particular, they share commonalities with many systems (as do frictionless springs). After that, I show how we used SDP in insect behavioral ecology. I describe the puzzles that needed to be solved, the SDP equations we used to solve the puzzles, and the experiments that we used to test the predictions of the models. I then briefly describe two other applications of SDP in biology: first, understanding the developmental pathways followed by steelhead trout in California and second skipped spawning by Norwegian cod. In both cases, modeling and empirical work were closely connected. I close with lessons learned and advice for the young mathematical biologists. © 2014, Society for Mathematical Biology.


Witko-Arsat V.,University of Paris Descartes | Reuter N.,University of Bergen | Mouthon L.,University of Paris Descartes
Current Opinion in Rheumatology | Year: 2010

PURPOSE OF REVIEW: This review focuses on proteinase 3 (PR3), the preferred target of antineutrophil cytoplasmic antibodies (ANCAs) in Wegener's granulomatosis. Deciphering the molecular associations that PR3 can make with its cognate partners might help to understand its pathophysiological significance in Wegener's granulomatosis and the potential role of ANCA as modulator of PR3 functions. RECENT FINDINGS: In neutrophils, PR3 is mainly localized within azurophilic granules but is also detected at the plasma membrane. Among PR3 partners (CD16, CD11b/CD18), CD177, a glycosylphosphatidylinositol (GPI)-anchored membrane protein is a potential receptor for PR3. In addition, PR3 can be externalized at the plasma membrane at a very early stage of neutrophil apoptosis, in the absence of degranulation. In these conditions, PR3 is associated with specific partners including phospholipidscramblase-1 and calreticulin. Interestingly, apoptosis-induced PR3 membrane expression significantly impaired macrophage phagocytosis. This new role of PR3 acting as a 'don't eat me signal' that delays neutrophil clearance might potentiate inflammation and autoimmunity. SUMMARY: Since PR3 membrane expression seems to represent a key element in the inflammatory and autoimmunity process, elucidation of the molecular basis of PR3 interaction with the plasma membrane or with receptor proteins led to the possibility of targeted therapy.© 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.


Background: In the general classical model for diagnoses based on a single analytic component, distributions of healthy and diseased are compared and several investigations of varying analytical performance on the percentage of misclassifications have been published. A new concept based on an alternative type of diagnosing, based on sharp decision limits has been introduced in diagnostic guidelines, but only a few publications on investigation of analytical performance have been seen. Methods: The two diagnostic models (bimodal and unimodal) based on natural logarithmic Gaussian distributions are simulated. Results: In the bimodal model it is possible to evaluate the influence of prevalence of disease in combination with varying analytical performances. In the unimodal model the prevalence is pre-decided by the chosen decision limit. In this model the influence of analytical performance is investigated for diagnosing diabetes using haemoglobin A1c (HbA1c), and for patients with high and low risk for coronary heart disease defined by serum-cholesterol concentrations. Conclusions: For HbA1c the guidelines and recommendations define a maximum inter-laboratory coefficient of variation of 3.5%, but this is in DCCT units (without a true zero-point), so after transformation to IFCC units (which are proportional) it was 5.2%, which allows for analytical bias as high as approximately ±9%. Consequently, analytical quality specifications should be separated as maximum bias and imprecision. © 2015 by De Gruyter.


Pilipczuk M.,University of Bergen
Leibniz International Proceedings in Informatics, LIPIcs | Year: 2013

The notions of cutwidth and pathwidth of digraphs play a central role in the containment theory for tournaments, or more generally semi-complete digraphs, developed in a recent series of papers by Chudnovsky, Fradkin, Kim, Scott, and Seymour [2, 3, 4, 7, 8, 10]. In this work we introduce a new approach to computing these width measures on semi-complete digraphs, via degree orderings. Using the new technique we are able to reprove the main results of [2, 8] in a unified and significantly simplified way, as well as obtain new results. First, we present polynomial-time approximation algorithms for both cutwidth and pathwidth, faster and simpler than the previously known ones; the most significant improvement is in case of pathwidth, where instead of previously known O(OPT)-approximation in fixed-parameter tractable time [5] we obtain a constant-factor approximation in polynomial time. Secondly, by exploiting the new set of obstacles for cutwidth and pathwidth, we show that topological containment and immersion in semi-complete digraphs can be tested in single-exponential fixed-parameter tractable time. Finally, we present how the new approach can be used to obtain exact fixed-parameter tractable algorithms for cutwidth and pathwidth, with single-exponential running time dependency on the optimal width.


Mackay A.,University of Wollongong | Stewart B.A.,University of Michigan | Chase B.M.,Montpellier University | Chase B.M.,University of Bergen
Journal of Human Evolution | Year: 2014

The later Pleistocene archaeological record of southernmost Africa encompasses several Middle Stone Age industries and the transition to the Later Stone Age. Through this period various signs of complex human behaviour appear episodically, including elaborate lithic technologies, osseous technologies, ornaments, motifs and abstract designs. Here we explore the regional archaeological record using different components of lithic technological systems to track the transmission of cultural information and the extent of population interaction within and between different climatic regions. The data suggest a complex set of coalescent and fragmented relationships between populations in different climate regions through the late Pleistocene, with maximum interaction (coalescence) during MIS 4 and MIS 2, and fragmentation during MIS 5 and MIS 3. Coalescent phases correlate with increases in the frequency of ornaments and other forms of symbolic expression, leading us to suggest that population interaction was a significant driver in their appearance. © 2014 Elsevier Ltd.


Kaplan G.,Hoboken University Medical Center | Kaplan G.,University of Bergen | Newcorn J.H.,The New School
Pediatric Clinics of North America | Year: 2011

Research in the past 2 decades showed that attention-deficit/hyperactivity disorder (ADHD) is a frequently occurring psychiatric disorder that causes considerable suffering to patients and their families. This article outlines current pharmacologic ADHD treatment options and focuses on their safety profile and efficacy. In addition, it addresses treatment selection, guidelines for monitoring treatment, and recent controversies in the field. © 2011 Elsevier Inc.


Hagen E.M.,University of Bergen
Acta neurologica Scandinavica. Supplementum | Year: 2010

To assess the temporal trends in the incidence and demographic characteristics of traumatic spinal cord injury (TSCI) with clinical concomitant traumatic brain injury (TBI), in an unselected, geographically defined cohort, 1952-2001. The patients were identified from hospital records. TBI was classified as none, mild, moderate, and severe. Of 336 patients, 157 (46.7%) patients had a clinical concomitant TBI. Clinical TBI was classified as mild in 30.1%, moderate in 11.0% and severe in 5.7%. The average annual incidence increased from 3.3 per million in the first decade to 10.7 per million in the last. Alcohol was the strongest risk factor of clinical TBI (OR = 3.69) followed by completeness of TSCI (OR = 2.18). The incidence of TSCI with concomitant TBI has increased during the last 50 years. Alcohol and completeness of injury are strong risk factors. Increased awareness of dual diagnoses is necessary.


Lind R.,University of Bergen
Scandinavian Journal of Gastroenterology | Year: 2010

Objective. We examined whether psychological factors such as general and gastrointestinal symptom-specific anxiety and depression could predict symptom severity in patients with unexplained, self-reported (subjective) food hypersensitivity. For the purpose, we translated and validated the Visceral Sensitivity Index (VSI). Material and methods. Seventy consecutive patients completed questionnaires for Hospital Anxiety and Depression Scale, VSI, Irritable Bowel Syndrome Symptom Questionnaire, and Subjective Health Complaints Inventory. Relationship between scores on psychological factors and scores on somatic symptoms were studied by multiple regression analyses. Results. Most patients reported non-gastrointestinal symptoms in addition to their irritable bowel syndrome complaints, but general and symptom-specific anxiety, and depression could not explain a significant amount of the variance in somatic complaints. Gastrointestinal symptom-specific anxiety was a significant predictor of gastrointestinal complaints (p = 0.02), and age was the sole significant predictor of non-gastrointestinal complaints (p = 0.01). Approximately 90% of the total variance in symptom severity remained unexplained by the psychological factors. The Norwegian version of the VSI had satisfactory validity (Cronbach alfa = 0.93). Symptom-specific and general anxiety were significantly correlated (r = 0.48, p ≤ 0.0001). Conclusions. Psychological factors were not major predictors of symptom severity in patients with subjective food hypersensitivity. The Norwegian version of VSI had satisfactory validity. © 2010 Informa UK Ltd.


Helle K.B.,University of Bergen | Corti A.,San Raffaele Scientific Institute
Cellular and Molecular Life Sciences | Year: 2015

Half a century after the discovery of chromogranin A as a secreted product of the catecholamine storage granules in the bovine adrenal medulla, the physiological role for the circulating pool of this protein has been recently coined, namely as an important player in vascular homeostasis. While the circulating chromogranin A since 1984 has proved to be a significant and useful marker of a wide range of pathophysiological and pathological conditions involving the diffuse neuroendocrine system, this protein has now been assigned a physiological "raison d'etre" as a regulator in vascular homeostasis. Moreover, chromogranin A processing in response to tissue damage and blood coagulation provides the first indication of a difference in time frame of the regulation of angiogenesis evoked by the intact chromogranin A and its two major peptide products, vasostatin-1 and catestatin. The impact of these discoveries on vascular homeostasis, angiogenesis, cancer, tissue repair and cardio-regulation will be discussed. © 2014 Springer Basel.


Rodriguez-Perez Q.,University of Bergen
Bulletin of the Seismological Society of America | Year: 2014

Regression models to predict pseudoacceleration response spectra (5% damping), peak ground acceleration (PGA), and peak ground velocity for high-frequency-depleted thrust near-trench events (5.1 ≤ Mw ≤ 8.0; 6≤H≤20km) in central Mexico, and normal-faulting inslab earthquakes (5.0 < Mw < 7.2; 55 ≤ H ≤ 198 km) in southern Mexico were developed using the one-stage maximum likelihood method. Ground-motion equations for near-trench events predict lower ground motions than those predicted by the inslab models, but also lower than relation-ships based on interplate data for central Mexico. Estimated inslab PGA obtained in this study for southern Mexico is lower than those from inslab events for central Mexico and Central America. Comparison of the inslab response spectra at low frequencies (f < 1 Hz) shows that differences in the decay functions for central and southern Mexico are relative minor. High-frequency ground motion (f > 5 Hz) and PGA amplitudes for central Mexico events attenuate faster than in the southern region.


Wu C.,Nanyang Technological University | Tai X.,University of Bergen
IEEE Transactions on Visualization and Computer Graphics | Year: 2010

Curvature flow (planar geometric heat flow) has been extensively applied to image processing, computer vision, and material science. To extend the numerical schemes and algorithms of this flow on surfaces is very significant for corresponding motions of curves and images defined on surfaces. In this work, we are interested in the geodesic curvature flow over triangulated surfaces using a level set formulation. First, we present the geodesic curvature flow equation on general smooth manifolds based on an energy minimization of curves. The equation is then discretized by a semi-implicit finite volume method (FVM). For convenience of description, we call the discretized geodesic curvature flow as dGCF. The existence and uniqueness of dGCF are discussed. The regularization behavior of dGCF is also studied. Finally, we apply our dGCF to three problems: the closed-curve evolution on manifolds, the discrete scale-space construction, and the edge detection of images painted on triangulated surfaces. Our method works for compact triangular meshes of arbitrary geometry and topology, as long as there are no degenerate triangles. The implementation of the method is also simple. © 2006 IEEE.


In the evaluation of performance of numerical models, static stability has gained less interest and attention than many other atmospheric parameters. Nevertheless, this parameter may in fact have rather large implications as it controls such features as gravity waves and turbulence. In this paper, a closer look has been taken at the behavior of static stability in a 3 km gridded numerical downscaling of the ERA-Interim reanalysis. The simulation performed with the Weather Research and Forecasting model has been nudged towards large scale analysis (spectral nudging) and satellite-derived ocean surface winds (Quick Scatterometer). The validation of low-level static stability was conducted in the North Sea using data from the FINO1 mast for year 2008, and a deeper part of the atmosphere was validated using the Ekofisk oil platform radiosonde data for years 2007-2010. The offshore mast comparison shows that the model over-predicts the number of unstable cases and that the unstable cases are not unstable enough. The model simulated a clear dependency between vertical wind shear and static stability; however, this was not the case in the observations. The model produced too few events with weak turbulence, but rather put the emphasis on intermediate turbulent intensities. With the radiosonde data measuring the static stability over a deeper part of the atmosphere, similar results as for lower levels showed. In addition, the temperature gradient across the inversion at the boundary layer top was too shallow in the model, potentially letting too much wave energy escape the boundary layer. © 2015 John Wiley & Sons, Ltd.


Rapp H.T.,University of Bergen
Journal of the Marine Biological Association of the United Kingdom | Year: 2015

Greenland has more than 200 years of history of studies of the sponge fauna and is the type locality for a number of species. Many of these have not been encountered since, and as the type material has been hard to find or even lost, their taxonomic status has remained uncertain. In this study all species of calcareous sponges previously reported from Greenland are reviewed. The revision is based predominantly on new or unidentified material collected during various expeditions, but also on material used by previous authors. This includes samples from all coasts of Greenland, from the southernmost Kap Farvel area to Peary Land on the northern coast, some of the northernmost records of calcareous sponges ever. Greenland is a transition zone between the western and eastern Atlantic boreal calcareous sponge faunas, being home to species from both sides of the North Atlantic combined with some true Arctic species. There is also a strong link between the Canadian and Greenlandic sponge faunas. Twenty-eight species have been identified, from which six are new to Greenland and one is new to science. New records for Greenland are: Clathrina arnesenae (Rapp, 2006); Clathrina camura (Rapp, 2006); Clathrina pellucida (Rapp, 2006); Sycon abyssale Borojevic & Graat-Kleeton, 1965; Leucandra valida Lambe, 1900; and Sycettusa thompsoni (Lambe, 1900). Clathrina tendali sp. nov. has been described from western Greenland and Leucosolenia corallorrhiza (Haeckel, 1872) and Leucandra penicillata (Schmidt, 1869) have been resurrected. Keys for identification of higher taxa and the different species of Greenlandic Calcarea are provided. Copyright © Marine Biological Association of the United Kingdom 2013.


Guthrie J.D.,University of Washington | Morison J.H.,University of Washington | Fer I.,University of Bergen
Journal of Geophysical Research: Oceans | Year: 2013

To determine whether deep background mixing has increased with the diminishment of the Arctic sea ice, we compare recent internal wave energy and mixing observations with historical measurements. Since 2007, the North Pole Environmental Observatory has launched expendable current probes (XCPs) as a part of annual airborne hydrographic surveys in the central Arctic Ocean. Mixing in the upper 500 m is estimated from XCP shear variance and Conductivity-Temperature-Depth (CTD) derived Brunt-Väisälä frequency. Internal wave energy levels vary by an order of magnitude between surveys, although all surveys are less energetic and show more vertical modes than typical midlatitude Garrett-Munk (GM) model spectra. Survey-averaged mixing estimates also vary by an order of magnitude among recent surveys. Comparisons between modern and historical data, reanalyzed in identical fashion, reveal no trend evident over the 30 year period in spite of drastic diminution of the sea ice. Turbulent heat fluxes are consistent with recent double-diffusive estimates. Both mixing and internal wave energy in the Beaufort Sea are lower when compared to both the central and eastern Arctic Ocean, and expanding the analysis to mooring data from the Beaufort Sea reveals little change in that area compared to historical results from Arctic Internal Wave Experiment. We hypothesize that internal wave energy remains lowest in the Beaufort Sea in spite of dramatic declines in sea ice there, because increased stratification amplifies the negative effect of boundary layer dissipation on internal wave energy. ©2013. American Geophysical Union. All Rights Reserved.


Havelin L.I.,University of Bergen
The Journal of bone and joint surgery. American volume | Year: 2011

The Nordic (Scandinavian) countries have had working arthroplasty registers for several years. However, the small numbers of inhabitants and the conformity within each country with respect to preferred prosthesis brands and techniques have limited register research. A collaboration called NARA (Nordic Arthroplasty Register Association) was started in 2007, resulting in a common database for Denmark, Norway, and Sweden with regard to hip replacements in 2008 and primary knee replacements in 2009. Finland joined the project in 2010. A code set was defined for the parameters that all registers had in common, and data were re-coded, within each national register, according to the common definitions. After de-identification of the patients, the anonymous data were merged into a common database. The first study based on this common database included 280,201 hip arthroplasties and the second, 151,814 knee arthroplasties. Kaplan-Meier and Cox multiple regression analyses, with adjustment for age, sex, and diagnosis, were used to calculate prosthesis survival, with any revision as the end point. In later studies, specific reasons for revision were also used as end points. We found differences among the countries concerning patient demographics, preferred surgical approaches, fixation methods, and prosthesis brands. Prosthesis survival was best in Sweden, where cement implant fixation was used more commonly than it was in the other countries. As the comparison of national results was one of the main initial aims of this collaboration, only parameters and data that all three registers could deliver were included in the database. Compared with each separate register, this combined register resulted in reduced numbers of parameters and details. In future collaborations of registers with a focus on comparing the performances of prostheses and articulations, we should probably include only the data needed specifically for the predetermined purposes, from registers that can deliver these data, rather than compiling all data from all registers that are willing to participate.


Otalora M.A.G.,Swedish Museum of Natural History | Jorgensen P.M.,University of Bergen | Wedin M.,Swedish Museum of Natural History
Fungal Diversity | Year: 2014

Phylogenetic studies have shown the need for a revised circumscription of generic boundaries in the jelly lichens (Collemataceae). Using a four-marker dataset from a recently published phylogeny of Collemataceae, we tested the monophyly of ten morphologically well-characterized groups. To achieve this, we performed Bayesian and maximum likelihood analyses. The monophyly of the ten morphological groups was confirmed. In order to reconcile molecular and morphological data into a formal classification, we here propose new generic delimitations in Collemataceae. Collema and Leptogium are re-circumscribed and six old generic names are resurrected to accommodate the Collema Crispum-group (Blennothallia), the Collema Tenax-group (Enchylium), the Collema Cristatum-group (Lathagrium), the Collema Occultatum-group (Rostania), the former small Leptogium species (Scytinium), and Leptogium diffractum (Pseudoleptogium). In addition, two new genera are described to accommodate Collema multipartitum (Callome) and the Collema Italicum-group (Paracollema). The presence/absence of a eucortex, which was earlier used as the cardinal character to define genera in the family, is still useful, but only in combination with other traits such as thallus habit (size), lobe size, ascospore characteristics, thallus anatomical structure, and habitat preference. A key to the genera is provided. Lectotypes are designated for Collema marginale Hoffm., Synechoblastus nigrescens (Huds.) Trevis., Eucollema (Cromb.) Horw., Collema section Enchylium Ach., Collema section Lathagrium Ach., Collema sect. Mallotium Ach., Collema section Scytinium Ach., Collemodium Nyl. ex Lamy, and Homodium Nyl. ex Olivier. © 2013 Mushroom Research Foundation.


Erdmann S.,Copenhagen University | Le Moine Bauer S.,Copenhagen University | Le Moine Bauer S.,University of Bergen | Garrett R.A.,Copenhagen University
Molecular Microbiology | Year: 2014

Infection of Sulfolobus islandicusREY15A with mixtures of different Sulfolobus viruses, including STSV2, did not induce spacer acquisition by the host CRISPR immune system. However, coinfection with the tailed fusiform viruses SMV1 and STSV2 generated hyperactive spacer acquisition in both CRISPR loci, exclusively from STSV2, with the resultant loss of STSV2 but not SMV1. SMV1 was shown to activate adaptation while itself being resistant to CRISPR-mediated adaptation and DNA interference. Exceptionally, a single clone S-1 isolated from an SMV1+STSV2-infected culture, that carried STSV2-specific spacers and had lost STSV2 but not SMV1, acquired spacers from SMV1. This effect was also reproducible on reinfecting wild-type host cells with a variant SMV1 isolated from the S-1 culture. The SMV1 variant lacked a virion protein ORF114 that was shown to bind DNA. This study also provided evidence for: (i) limits on the maximum sizes of CRISPR loci; (ii) spacer uptake strongly retarding growth of infected cultures; (iii) protospacer selection being essentially random and non-directional, and (iv) the reversible uptake of spacers from STSV2 and SMV1. A hypothesis is presented to explain the interactive conflicts between SMV1 and the host CRISPR immune system. © 2013 The Authors.


Brackman D.,University of Bergen
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association | Year: 2011

A 4-year-old boy presented with proteinuria and developed progressive renal failure over 6 years. In the patient's family, five individuals were affected with atypical haemolytic uraemic syndrome (aHUS) but not the patient. Renal biopsies (n = 3) showed glomerular basement membrane thickening with double contours, endothelial swelling and deposits of C3 and C1q. Electron microscopy revealed mesangial and subendothelial electron-dense deposits. Complement mutations in membrane cofactor protein (Y155D) and C3 (R713W and G1094R) were detected in all affected family members. The patient also had transient autoantibodies to factor H. The findings suggest that aHUS and glomerulopathy resembling membranoproliferative glomerulonephritis may have a common molecular background.


Jackson C.A.-L.,Imperial College London | Rotevatn A.,University of Bergen
Journal of Structural Geology | Year: 2013

In this paper we determine the structure and evolution of a normal fault system by applying qualitative and quantitative fault analysis techniques to a 3D seismic reflection dataset from the Suez Rift, Egypt. Our analysis indicates that the October Fault Zone is composed of two fault systems that are locally decoupled across a salt-bearing interval of Late Miocene (Messinian) age. The sub-salt system offsets pre-rift crystalline basement, and was active during the Late Oligocene-early Middle Miocene. It is composed of four, planar, NW-SE-striking segments that are hard- linked by N-S-striking segments, and up to 2 km of displacement occurs at top basement, suggesting that this fault system nucleated at or, more likely, below this structural level. The supra-salt system was active during the Pliocene-Holocene, and is composed of four, NW-SE-striking, listric fault segments, which are soft-linked by unbreached relay zones. Segments in the supra-salt fault system nucleated within Pliocene strata and have maximum throws of up to 482 m. Locally, the segments of the supra-salt fault system breach the Messinian salt to hard-link downwards with the underlying, sub-salt fault system, thus forming the upper part of a fault zone composed of: (i) a single, amalgamated fault system below the salt and (ii) a fault system composed of multiple soft-linked segments above the salt. Analysis of throw-distance (T-x) and throw-depth (T-z) plots for the supra-salt fault system, isopach maps of the associated growth strata and backstripping of intervening relay zones indicates that these faults rapidly established their lengths during the early stages of their slip history. The fault tips were then effectively 'pinned' and the faults accumulated displacement via predominantly downward propagation. We interpret that the October Fault Zone had the following evolutionary trend; (i) growth of the sub-salt fault system during the Oligocene-to-early Middle Miocene; (ii) cessation of activity on the sub-salt fault system during the Middle Miocene-to-?Early Pliocene; (iii) stretching of the sub- and supra-salt intervals during Pliocene regional extension, which resulted in mild reactivation of the sub-salt fault system and nucleation of the segmented supra-salt fault system, which at this time was geometrically decoupled from the sub-salt fault system; and (iv) Pliocene-to-Holocene growth of the supra-salt fault system by downwards vertical tip line propagation, which resulted in downward breaching of the salt and dip-linkage with the sub-salt fault system. The structure of the October Fault Zone and the rapid establishment of supra-salt fault lengths are compatible with the predictions of the coherent fault model, although we note that individual segments in the supra-salt array grew in accordance with the isolated fault model. Our study thereby indicates that both coherent and isolated fault models may be applicable to the growth of kilometre-scale, basin-bounding faults. Furthermore, we highlight the role that fault reactivation and dip-linkage in mechanically layered sequences can play in controlling the three-dimensional geometry of normal faults. © 2013 Elsevier Ltd. All rights reserved.


At the outset it may seem reasonable to expect that dust clouds from combustible nm-particle powders will exhibit extreme ignition sensitivities (very low MIEs) and extreme explosion rates (very high KSt-values). However, there are two basic reasons why this is not necessarily the case. Firstly, complete transformation of bulk nm-particle powders into dust clouds consisting of well-dispersed primary particles is extremely difficult to accomplish, due to very strong inter-particle forces. Secondly, the extremely fast coagulation process in nm particle clouds of explosive mass concentrations would transform the primary particles in a well-dispersed cloud into much larger agglomerates within fractions of a second. The paper discusses these aspects in relation to recent published MIE data and KSt-values for some nm powders. © 2013 Elsevier B.V.


Fisk M.,Oregon State University | McLoughlin N.,University of Bergen
Geosphere | Year: 2013

We provide a comprehensive photographic atlas of the intricate alteration features found in glass in igneous rocks from the ocean basins. The samples come from surface and subsurface rocks from oceanic rises and seamounts of the ocean basins and some marginal seas. These textures have previously been termed "bioalteration textures" by those who consider them as potentially biogenic in origin, or as "etch pits" by those who prefer a non-biogenic interpretation. Here, transmitted-light color photomicrographs are provided to illustrate the range of granular and tubular textures as well as their relation to fractures, minerals, vesicles, and multiple episodes of alteration in the same sample. The tubular forms are described using seven morphological characteristics: (1) length and width; (2) density; (3) curvature; (4) roughness; (5) variations in width; (6) branching; and (7) tunnel contents. The photomicrographs are a starting point for understanding the factors that control the formation of the alteration textures, for evaluating the biogenicity of the various forms, for inferring subsurface conditions during alteration, and for making comparisons to similar textures in ancient ophiolites, some of which have been attributed to the earliest life on Earth. © 2013 Geological Society of America.


Kaarboe O.,University of Bergen | Siciliani L.,University of York
Health Economics | Year: 2011

We present a model of optimal contracting between a purchaser and a provider of health services when quality has two dimensions. We assume that: (i) the provider is (at least to some extent) altruistic; (ii) one dimension of quality is verifiable (dimension 1) and one dimension is not verifiable (dimension 2); (iii) the two quality dimensions can be either substitutes or complements. Our main result is that setting the price equal to the marginal benefit of the verifiable quality dimension can be optimal even if the two quality dimensions are substitutes. Copyright © 2010 John Wiley & Sons, Ltd.


Chiarugi A.,University of Florence | Dolle C.,University of Florence | Felici R.,University of Florence | Ziegler M.,University of Bergen
Nature Reviews Cancer | Year: 2012

NAD is a vital molecule in all organisms. It is a key component of both energy and signal transduction - processes that undergo crucial changes in cancer cells. NAD + -dependent signalling pathways are many and varied, and they regulate fundamental events such as transcription, DNA repair, cell cycle progression, apoptosis and metabolism. Many of these processes have been linked to cancer development. Given that NAD + -dependent signalling reactions involve the degradation of the molecule, permanent nucleotide resynthesis through different biosynthetic pathways is crucial for incessant cancer cell proliferation. This necessity supports the targeting of NAD metabolism as a new therapeutic concept for cancer treatment. © 2012 Macmillan Publishers Limited. All rights reserved.


Purohit M.R.,University of Bergen
Applied Immunohistochemistry and Molecular Morphology | Year: 2016

BACKGROUND:: Extrapulmonary tuberculosis (EPTB) constitutes about 15% to 20% of all cases of tuberculosis (TB). The confirmation of EPTB has always been a challenge to laboratory personnel. We aim to evaluate the diagnostic potential of immunostaining with anti-MPT64 in various EPTB specimens. MATERIALS AND METHODS:: We studied a total of 51 TB cases and 38 non-TB control specimens comprising of fine-needle aspirates and formalin-fixed biopsies. These were investigated using a combination of the Ziehl-Neelsen method, the Lowenstein-Jensen culture, immunostaining with anti-MPT64 and anti-BCG, and nested-polymerase chain reaction (PCR) for IS6110. Results of all the tests were compared using nested-PCR as the gold standard. RESULTS:: Diagnostic validation of immunostaining for anti-MPT64 was performed using nested-PCR as the gold standard. The overall sensitivity, specificity, and positive and negative predictive values for immunostaining with anti-MPT64 were 100%, 97%, 97%, and 100%, respectively. CONCLUSIONS:: Immunostaining using anti-MPT64 is a rapid and sensitive method for establishing an early and specific diagnosis of Mycobacterium tuberculosis infection. The technique is simple to be incorporated into routine pathology laboratories. Copyright 2016 Wolters Kluwer Health, Inc. All rights reserved.


Haldorsen I.S.,University of Bergen
Nature reviews. Endocrinology | Year: 2012

In neonatal diabetes mellitus resulting from mutations in EIF2AK3, PTF1A, HNF1B, PDX1 or RFX6, pancreatic aplasia or hypoplasia is typical. In maturity-onset diabetes mellitus of the young (MODY), mutations in HNF1B result in aplasia of pancreatic body and tail, and mutations in CEL lead to lipomatosis. The pancreas is not readily accessible for histopathological investigations and pancreatic imaging might, therefore, prove important for diagnosis, treatment, and research into these β-cell diseases. Advanced imaging techniques can identify the pancreatic features that are characteristic of inherited diabetes subtypes, including alterations in organ size (diffuse atrophy and complete or partial pancreatic agenesis), lipomatosis and calcifications. Consequently, in patients with suspected monogenic diabetes mellitus, the results of pancreatic imaging could help guide the molecular and genetic investigation. Imaging findings also highlight the critical roles of specific genes in normal pancreatic development and differentiation and provide new insight into alterations in pancreatic structure that are relevant for β-cell disease.


Nordbotten J.M.,University of Bergen | Nordbotten J.M.,Princeton University
Water Resources Research | Year: 2014

Cell-centered finite volume methods are prevailing in numerical simulation of flow in porous media. However, due to the lack of cell-centered finite volume methods for mechanics, coupled flow and deformation is usually treated either by coupled finite-volume-finite element discretizations, or within a finite element setting. The former approach is unfavorable as it introduces two separate grid structures, while the latter approach loses the advantages of finite volume methods for the flow equation. Recently, we proposed a cell-centered finite volume method for elasticity. Herein, we explore the applicability of this novel method to provide a compatible finite volume discretization for coupled hydromechanic flows in porous media. We detail in particular the issue of coupling terms, and show how this is naturally handled. Furthermore, we observe how the cell-centered finite volume framework naturally allows for modeling fractured and fracturing porous media through internal boundary conditions. We support the discussion with a set of numerical examples: the convergence properties of the coupled scheme are first investigated; second, we illustrate the practical applicability of the method both for fractured and heterogeneous media. Key Points Formulation of consistent discretization of fluid flow and mechanical deformation within a finite volume framework Numerical validation of convergence and application to model problems Application to fractured and fracturing porous media © 2014. The Authors.


Rommetveit K.,University of Bergen
Cambridge Quarterly of Healthcare Ethics | Year: 2011

We have arrived at a situation in which policymakers and ethicists are considering abandoning informed consent in the governance of certain new technologies, many of which are related to large-scale information systems. A paradigm case is the problem with using individuals' informed consent to regulate biobanks. As sometimes suggested, there is a need for "new ethical frameworks." © 2011 Cambridge University Press.


Background: Persistent organic pollutants (POPs) are hazardous chemicals omnipresent in our food chain, which have been internationally regulated to ensure public health. Initially described for their potency to affect reproduction and promote cancer, recent studies have highlighted an unexpected implication of POPs in the development of metabolic diseases like type 2 diabetes and obesity. Based on this novel knowledge, this article aims at stimulating discussion and evaluating the effectiveness of current POP legislation to protect humans against the risk of metabolic diseases. Furthermore, the regulation of POPs in animal food products in the European Union (EU) is addressed, with a special focus on marine food since it may represent a major source of POP exposure to humans. Discussion: There is mounting scientific evidence showing that current POP risk assessment and regulation cannot effectively protect humans against metabolic disorders. Better regulatory control of POPs in dietary products should be of high public health priority. Summary: The general population is exposed to sufficient POPs, both in term of concentration and diversity, to induce metabolic disorders. This situation should attract the greatest attention from the public health and governmental authorities. © 2012 Ruzzin; licensee BioMed Central Ltd.


Van De Vliert E.,University of Groningen | Van De Vliert E.,University of Bergen | Postmes T.,University of Groningen
Behavioral and Brain Sciences | Year: 2012

A 121-nation study of societal collectivism and a 174-nation study of political autocracy show that parasitic stress does not account for any variation in these components of culture once the interactive impacts of climatic demands and income resources have been accounted for. Climato-economic livability is a viable rival explanation for the reported effects of parasitic stress on culture. © 2012 Cambridge University Press.


Torkildsen O.,University of Bergen
Acta neurologica Scandinavica. Supplementum | Year: 2012

Several studies have indicated month of birth as a risk factor for multiple sclerosis (MS) susceptibility and disease progression. We performed a systematic search on PubMed and Medline up to May 2012 using the search string 'multiple sclerosis' and 'month of birth' or 'season of birth'. In addition, congress abstracts and the reference lists of the publications identified were examined for further citations of relevance. A total of fifteen published studies and two congress abstracts were found on the effect of month or season of birth on MS risk (sixteen in the northern and one in the southern hemisphere). Most studies in the northern hemisphere detected an excess of MS births in spring and a decrease in autumn. In the southern hemisphere, a reverse pattern was detected, with an excess in November and a decrease in April. Only three studies did not report any month of birth effect, all in low-risk areas for MS. Five studies have analysed a possible effect on disease course by month of birth. Of these, two studies reported an association between month of birth and age at onset of relapsing-remitting MS, with a younger disease onset for those born in the winter months. No consistent findings have been detected on the association between month of birth and disease progression. The month of birth effect is consistently found to influence the risk of MS, and the effect seems to be most prominent in high-risk areas of the disease, especially in areas with low sunlight exposure. There seems to be little or no month of birth effects in areas with high sunlight exposure. These findings indicate a possible role for vitamin D concentrations during pregnancy or early life of the newborn. A possible effect of vitamin D supplementation needs to be further investigated. © 2012 John Wiley & Sons A/S.


Lauvset S.K.,University of Bergen | Lauvset S.K.,ETH Zurich | Gruber N.,ETH Zurich
Marine Chemistry | Year: 2014

Presently available direct pH measurements do not have a sufficient data density in space or time in order to determine long-term trends across wider geographic regions, limiting our ability to assess the magnitude and impacts of ocean acidification. We overcome this limitation by using the much more frequently measured fugacity of CO2 (fCO2), as synthesized in the SOCAT data product, from which we calculate pH using algorithms for alkalinity based on temperature and salinity. The estimated pH at 25°C, i.e., pHsws 25°C has a calculation error of 0.0033±0.0003, and evaluation using co-located pH observations yields a RMSE of 0.010 and a non-significant bias of 0.004. The estimated pHsws 25°C is rather sensitive to uncertainties and biases in fCO2, while uncertainties in alkalinity, temperature, and salinity matter much less. The high precision and low bias of the computed pH permit us to apply this method to data from the North Atlantic Subpolar Gyre, for which we find a statistically significant trend in surface ocean pHsws insitu of -0.0022±0.0004yr-1 over the period 1981 to 2007. This long-term trend in pH is nearly entirely driven by the long-term trend in surface ocean fCO2, while the impact of temperature is negligible. This pH trend is very close to that expected based on the assumption of thermodynamic equilibrium of CO2 between the atmosphere and the surface ocean. © 2014 Elsevier B.V.


Malterud K.,University of Bergen
Scandinavian journal of primary health care | Year: 2010

To explore obese patients' experiences with GPs' management of their weight problems. Focus-group study with a purposive sample of 13 participants (eight women and five men), aged 30-55 years, with BMI above 40, or BMI above 35 with additional weight-related problems. Two focus-group interviews were conducted, inviting the participants to speak about their health care experiences from general practice. Analysis applied Systematic Text Condensation inspired by Giorgi's approach, searching for issues describing or discussing participants' experiences of GPs' obesity management. Obese patients want their GPs to put their weight problems on the agenda. When the patient appears reluctant, it may be a sign of embarrassment rather than rejection of the issue. However, restricted attention to obesity could lead to neglect of patients' problems. Participants complained that GPs often demonstrated insufficient engagement and knowledge regarding service resources for obesity treatment, leaving the responsibility for information on available referral resources to the patient. Finally, considerate attitudes in the GPs are needed for follow-up to be experienced as helpful by the patients. Vulnerable feelings of failure could be reinforced by well-intended advice. Degrading attitudes were perceived as especially subversive when they came from doctors. The challenge for the GP is to increase his or her competence in individualized and evidence-based counselling, while acknowledging the efforts needed by the patient to achieve permanent change, and shifting attention from shame to coping.


Schultz R.A.,University of Nevada, Reno | Okubo C.H.,U.S. Geological Survey | Fossen H.,University of Bergen
Geophysical Research Letters | Year: 2010

Determining the rock properties that permit or impede the growth of compaction bands in sedimentary sequences is a critical problem of importance to studies of strain localization and characterization of subsurface geologic reservoirs. We determine the porosity and average grain size of a sequence of stratigraphic layers of Navajo Sandstone that are then used in a critical state model to infer plastic yield envelopes for the layers. Pure compaction bands are formed in layers having the largest average grain sizes (0.42-0.45 mm) and porosities (28%), and correspondingly the smallest values of critical pressure (∼22 MPa) in the sequence. The results suggest that compaction bands formed in these layers after burial to ∼1.5 km depth in association with thrust faulting beneath the nearby East Kaibab monocline, and that hardening of the yield caps accompanied compactional deformation of the layers. © 2010 by the American Geophysical Union.


Li N.,Southwest Jiaotong University | Helleseth T.,University of Bergen | Tang X.,Southwest Jiaotong University
Finite Fields and their Applications | Year: 2013

A class of permutation polynomials with given form over finite fields is investigated in this paper, which is a further study on a recent work of Zha and Hu. Based on some particular techniques over finite fields, two results obtained by Zha and Hu are improved and new permutation polynomials are also obtained. © 2013 Elsevier Inc.


Macias-Fauria M.,University of Oxford | Willis K.J.,University of Oxford | Willis K.J.,University of Bergen
Global Ecology and Biogeography | Year: 2013

Aim: Bioclimatic envelope models (BEMs) for seven economically important tree species in Europe were independently validated using a hindcasting approach and fossil pollen records spanning the last 1000 years, including the Medieval Warm Period (MWP), the Little Ice Age (LIA) and the 20th century (PRES). The aim was to determine the accuracy of combining BEMs and palaeoecological data to predict continental-scale changes in distribution, and the availability of fossil data to hindcast economically important species. Location: Europe, 11°W-33°E, 33-72°N. Methods: Eight types of BEMs were implemented in this study, covering most state-of-the-art modelling techniques. Present and palaeoclimatic data were obtained from the atmosphere-ocean global circulation model ECHO-G. The last millennium was divided into three climatically distinct periods: the MWP (ad 900-1300), the LIA (ad 1600-1850) and PRES (ad 1900-2000). Models were calibrated for each period and validated with climatic and pollen data from the remaining periods. Successfully validated models were projected onto a 1° European grid. Results: BEMs were successfully validated with independent data. The average area under the curve statistic showed strong model performance, indicating: (1) the strength of BEMs for modelling current and future distributions and, (2) the potential of fossil pollen records to undertake these approaches. European-scale 1°- gridded maps of probability of occurrence largely agreed with observed 20th-century distributions for most taxa, allowing the construction of past modelled species distributions. Main conclusions: Results suggest a high potential for BEMs to be used to model future species distributions, and highlight the importance of palaeoecological data to independently validate these models, taking into account the scales at which these data operate. Although valid, BEMs showed poorer performance with heavily managed species and/or those growing in heterogeneous terrain or with discontinuous distributions. The last millennium in Europe was characterized by an increase in woody crop species and a decline of forest species, suggesting increasing land use by humans. © 2012 Blackwell Publishing Ltd.


Hejnol A.,University of Bergen | Lowe C.J.,Stanford University
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2015

Molecular biology has provided a rich dataset to develop hypotheses of nervous system evolution. The startling patterning similarities between distantly related animals during the development of their central nervous system (CNS) have resulted in the hypothesis that a CNS with a single centralized medullary cord and a partitioned brain is homologous across bilaterians. However, the ability to precisely reconstruct ancestral neural architectures from molecular genetic information requires that these gene networks specifically map with particular neural anatomies. A growing body of literature representing the development of a wider range of metazoan neural architectures demonstrates that patterning gene network complexity is maintained in animals with more modest levels of neural complexity. Furthermore, a robust phylogenetic framework that provides the basis for testing the congruence of these homology hypotheses has been lacking since the advent of the field of ‘evo-devo’. Recent progress inmolecular phylogenetics is refining the necessary framework to test previous homology statements that span large evolutionary distances. In this review,we describe recent advances in animal phylogeny and exemplify for two neural characters—the partitioned brain of arthropods and the ventral centralized nerve cords of annelids—a test for congruence using this framework. The sequential sister taxa at the base of Ecdysozoa and Spiralia comprise small, interstitial groups. This topology is not consistent with the hypothesis of homology of tripartitioned brain of arthropods and vertebrates as well as the ventral arthropod and rope-like ladder nervous system of annelids. There can be exquisite conservation of gene regulatory networks between distantly related groupswith contrasting levels of nervous system centralization and complexity. Consequently, the utility of molecular characters to reconstruct ancestral neural organization in deep time is limited. © 2015 The Author(s) Published by the Royal Society. All rights reserved.


Thompson J.C.,University of Queensland | Henshilwood C.S.,University of Witwatersrand | Henshilwood C.S.,University of Bergen
Journal of Archaeological Science | Year: 2014

Tortoises are one of the most common faunal components at many Palaeolithic archaeological sites across the Old World. They provide protein, fat, and other 'animal' resources in a 'collectable' package. However, for most sites their interpretation as human food debris is based only on association, rather than demonstrated through taphonomic analysis. Because of their very different anatomical configuration compared to mammals, it is difficult to conduct such analyses by directly applying the taphonomic methods used to interpret large mammal assemblages. Tortoise-specific taphonomic analysis is presented here for the Still Bay layers at the important Middle Stone Age (MSA) site of Blombos Cave (BBC), Western Cape, South Africa. Research on MSA subsistence systems at sites such as BBC has almost exclusively relied on analysis of large ungulate remains, in spite of the fact that many of these key sites contain equal or greater numbers of tortoise fragments. In this analysis we show that human modification is common on the BBC tortoises, and that there are consistent patterns of fragmentation and burning that indicate set processing sequences including cooking while in the shell, hammerstone percussion, and human chewing of limbs. The almost exclusive dominance of the angulate tortoise, Chersina angulata, is confirmed by full skeletal element analyses rather than only counts of single elements such as humeri. The sex distribution can be reconstructed for this species, and is female-biased. For all tortoise assemblages, taxonomic and skeletal element abundance data should be calculated from a sample of complete elements, or at minimum the entoplastron and humerus. A sample of shell and limb/girdle elements should also be subjected to microscopic bone surface modification analysis, as modifications are often rare or subtle but highly informative. Using this approach, analysis of breakage patterns, bone surface modification, and burning patterns can be understood together to specifically reconstruct tortoise collection, processing, and human dietary significance across a range of archaeological sites. © 2013 Elsevier Ltd.


Ulvestad E.,University of Bergen
Methods in Molecular Biology | Year: 2012

Accumulating evidence has made clear that experiencethe knowledge an individual acquires during a lifetime of sensing and actingis of fundamental biological relevance. Experience makes an impact on all adaptive systems, including the endocrine, immune, and nerve systems, and is of the essence, not only for the unfolding of an organisms' healthy status, but also for the development of malfunctional traits. Nevertheless, experience is often excluded from empirical approaches. A variety of complex interactions that influence life histories are thereby neglected. Such ignorance is especially detrimental for psychoneuroimmunology, the science that seeks to understand how the exquisite and dynamic interplay between mind, body, and environment relates to behavioral characteristics. The article reviews claims for incorporating experience as a member of good explanatory standing in biology and medicine, and more specifically, claims that experiential knowledge is required to enable meaningful and relevant explanations and predictions in the psychoneuroimmunological realm. © 2012 Springer Science+Business Media, LLC.


Vestheim H.,University of Bergen
Methods in molecular biology (Clifton, N.J.) | Year: 2011

"Universal" or group-specific PCR primers have a tendency to predominately hybridise with the common sequences in samples with mixed templates. The result is that the rarer sequences are seldom retrieved by cloning or sequencing. The use of a blocking oligonucleotide (oligo) designed to specifically prevent amplification of dominant or unwanted DNA templates is an easy way to improve the amplification of rarer sequences. Here, we describe the different types of blocking principles and the different types of blocking oligos and give guidelines and examples of their application.


Konig C.,University of Bergen | Segura L.,Government of Catalonia GENCAT
Addiction | Year: 2011

Introduction The importance of building and strengthening effective infrastructures within the field of public health has increasingly been recognized. A wide variety of actors and structures can be identified for alcohol policy, including systems for policy development, monitoring, research and work-force development, but too little is known about the complex systems of infrastructure available across European countries and their impact on alcohol policy. Objective This study is part of the Alcohol Measures for Public Health Research Alliance (AMPHORA) project, and aims to map existing infrastructures, but also to examine the relationship between infrastructures and alcohol policy change. Methods A survey of alcohol policy infrastructure and infrastructure needs at the national level will be conducted using an updated and adapted questionnaire based on the Health Promotion (HP) Source Project tool. Case studies involving in-depth interviews will be conducted for a selection of countries. Data will be analysed descriptively, mapping alcohol policy infrastructure and identifying needs to reveal any relationship between infrastructure and alcohol policy. Expected results This study can contribute to building the scientific knowledge base on this topic as well to policy development. First, the Alcohol Measures for Public Health Research Alliance will produce an extended map of alcohol policy infrastructures in a wide range of European countries. Secondly, the Alcohol Measures for Public Health Research Alliance will foster a better understanding and expand the knowledge base on the role and influence of infrastructure on alcohol policy and practice. Recommendations deriving from this study will identify the need for better utilization of existing infrastructures and for the development of new infrastructures, necessary to develop and implement effective alcohol policy from a public health perspective. © 2011 The Authors, Addiction © 2011 Society for the Study of Addiction.


Wesnes S.L.,University of Bergen
International Urogynecology Journal and Pelvic Floor Dysfunction | Year: 2014

Excessive weight is an established and potent risk factor for urinary incontinence (UI) among women of all ages. Although few would doubt that weight plays a role in UI, there are still many uncertainties regarding weight as a risk factor. It must be clarified whether body mass index (BMI) is a better estimate than weight, waist circumference, or waist-hip ratio. It is not clear how the distribution of weight affects UI. Does being overweight due to heavy muscles, edema, or pregnancy lead to UI or only being overweight due to adiposity? It is unclear for how long a person's overweight must persist to lead to UI. We do not know whether weight is an appropriate measure of exposure or whether the association between weight and UI is confounded by socioeconomic status, diet, disease, or weight-related hormonal changes. This article summarizes knowledge gaps on the association between weight and UI. © 2013 The International Urogynecological Association.


Carlsen B.,University of Bergen
BMJ Quality and Safety | Year: 2011

Background: Clinical guidelines are important for ensuring quality of treatment and care. For this reason, it is essential that clinicians adhere to guidelines. Review studies conclude that barriers to using guidelines are context specific. Nevertheless, there is a lack of studies that compare the attitudes of different groups of doctors to guidelines. Objectives: To survey the attitudes of Norwegian medical practitioners to clinical guidelines and the reasons for any scepticism, and to compare general practitioners (GPs) with other medical doctors in Norway in this respect. Method: Postal questionnaire to a panel of 1649 Norwegian medical doctors. Results: 1072 doctors responded (65%). 97% claimed to be familiar with and following guidelines. A majority expressed confidence in guidelines issued by the health authorities and the medical association. GPs are significantly more uncertain about the legal status of, accessibility of and evidence in guidelines than other doctors. The most important barriers to guideline adherence are concerns about the uniqueness of individual cases and reliance on one's own professional discretion. Both groups rank attitudinal constraints higher than practical constraints, but GPs more often report practical issues as reasons for non-adherence. Conclusion: It is suggested that creating trust in guidelines could be more important than more efforts to improve guideline format and accessibility. It may also be worth considering whether guidelines should be implemented using different processes in generalist and specialist care.


Waldmann N.,University of Bergen | Torfstein A.,Lamont Doherty Earth Observatory | Stein M.,Geological Survey of Israel
Geology | Year: 2010

The rain regime of the Levant during the late Quaternary was controlled primarily by Mediterranean cyclonic systems associated with North Atlantic climate shifts. Lake levels in the Dead Sea basin have been robust recorders of the regional hydrology and generally indicate highstand (wet) conditions throughout glacial intervals and lowstands (dry) during interglacials. However, sporadic deposition of travertines and speleothems occurred in the Negev Desert and Arava Valley during past interglacials, suggesting intrusions of humidity from southern sources probably in association with enhanced activity of mid-latitude Red Sea synoptic troughs and/or low-latitude tropical plumes. The southerly incursions of wetness were superimposed on the long-term interglacial Levantine arid conditions, as reflected by the current prevailing hyperaridity, and could have had an important impact on human migration through the Red Sea-Dead Sea corridor. © 2010 Geological Society of America.


Mecking J.V.,Leibniz Institute of Marine Science | Keenlyside N.S.,University of Bergen | Greatbatch R.J.,Leibniz Institute of Marine Science
Climate Dynamics | Year: 2014

Observations show a multidecadal signal in the North Atlantic ocean, but the underlying mechanism and cause of its timescale remain unknown. Previous studies have suggested that it may be driven by the North Atlantic Oscillation (NAO), which is the dominant pattern of winter atmospheric variability. To further address this issue, the global ocean general circulation model, Nucleus for European Modelling of the Ocean (NEMO), is driven using a 2,000 years long white noise forcing associated with the NAO. Focusing on key ocean circulation patterns, we show that the Atlantic Meridional Overturning Circulation (AMOC) and Sub-polar gyre (SPG) strength both have enhanced power at low frequencies but no dominant timescale, and thus provide no evidence for a oscillatory ocean-only mode of variability. Instead, both indices respond linearly to the NAO forcing, but with different response times. The variability of the AMOC at 30°N is strongly enhanced on timescales longer than 90 years, while that of the SPG strength starts increasing at 15 years. The different response characteristics are confirmed by constructing simple statistical models that show AMOC and SPG variability can be related to the NAO variability of the previous 53 and 10 winters, respectively. Alternatively, the AMOC and the SPG strength can be reconstructed with Auto-regressive (AR) models of order seven and five, respectively. Both statistical models reconstruct interannual and multidecadal AMOC variability well, while on the other hand, the AR(5) reconstruction of the SPG strength only captures multidecadal variability. Using these methods to reconstruct ocean variables can be useful for prediction and model intercomparision. © 2013 Springer-Verlag Berlin Heidelberg.


Moxnes E.,University of Bergen
Ecological Economics | Year: 2014

Climate policy recommendations differ widely because of disagreements over what discount rates to use. Disagreement reduces the impact of economic models and signals a need for improved methodology. The problem is related to the choice of intergenerational welfare functions. A first questionnaire finds that the standard welfare function (SWF) fails to capture people's dislike of overshooting and fluctuating consumption paths. A second questionnaire reveals that when very-long-term sustainability of well-being is threatened, people's implicit discount rates resemble the low estimates used by the Stern Review. An alternative welfare function (AWF) reflecting consumption growth can potentially capture the preference structure revealed in both questionnaires. This makes the AWF an interesting candidate when searching for policies for sustainable development under uncertainty. Importantly, the questionnaires demonstrate that people are able to choose among policies by inspecting time graphs of policy consequences. Thus, it is possible to circumvent the complexities and disagreements introduced by welfare functions and discounting. © 2014.


Lundberg S.,University of Bergen | Pollak R.A.,Washington University in St. Louis
Future of Children | Year: 2015

Since 1950, marriage behavior in the United States has changed dramatically. Though most men and women still marry at some point in their lives, they now do so later and are more likely to divorce. Cohabitation has become commonplace as either a precursor or an alternative to marriage, and a growing fraction of births take place outside marriage. We’ve seen a retreat from marriage within all racial and ethnic groups and across the socioeconomic spectrum. But the decoupling of marriage and parenthood has been much less prevalent among college graduates. Why are college graduates such a prominent exception? Some scholars argue that marriage has declined furthest in low-income communities because men with less education have seen their economic prospects steadily diminish, and because welfare and other social programs have let women rear children on their own. Others contend that poor women have adopted middle-class aspirations for marriage, leading them to establish unrealistic economic prerequisites. The problem with these explanations, write Shelly Lundberg and Robert Pollak, is that they focus on barriers to marriage only in very poor communities. Yet we’ve seen a retreat from marriage among a much broader swath of the population. Lundberg and Pollak argue that the sources of gains from marriage have changed in such a way that families with high incomes and high levels of education have the greatest incentives to maintain long-term relationships. As women’s educational attainment has overtaken that of men, and as the ratio of men’s to women’s wages has fallen, they write, traditional patterns of gender specialization in household and market work have weakened. The primary source of gains from marriage has shifted from production of household services to investment in children. For couples whose resources allow them to invest intensively in their children, marriage provides a commitment mechanism that supports such investment. For couples who lack the resources to invest intensively in their children, on the other hand, marriage may not be worth the cost of limited independence and potential mismatch. © 2015 by The Trustees of Princeton University, All rights reserved.


Hole K.J.,University of Bergen
Computer | Year: 2016

A population model shows that distrust in e-government services-the belief that the service deliberately sabotages the user's intent-spreads rapidly even when problems affect only a few users. Strategies such as user-focused development and the use of cloud-based services can help mitigate that distrust. © 2016 IEEE.


Hughes A.L.C.,University of Bergen | Clark C.D.,University of Sheffield | Jordan C.J.,British Geological Survey
Quaternary Science Reviews | Year: 2014

We present a 10-stage reconstruction of the evolution in ice-flow patterns of the last British Ice Sheet from build-up to demise derived from geomorphological evidence. 100 flowsets identified in the subglacial bedform record (drumlins, mega-scale glacial lineations, and ribbed moraine) are combined with ancillary evidence (erratic-transport paths, absolute dates and a semi-independently reconstructed retreat pattern) to define flow patterns, ice divides and ice-sheet margins during build-up, maximum glaciation and retreat. Overprinting and cross-cutting of landform assemblages are used to define the relative chronology of flow patterns and a tentative absolute chronology is presented based on a collation of available dates for ice advance and retreat. The ice-flow configuration of the last British Ice Sheet was not static. Some ice divides were remarkably stable, persisting through multiple stages of the ice-sheet evolution, whereas others were transient features existing for a short time and/or shifting in position 10skm. The 10 reconstructed stages of ice-sheet geometry capture two main modes of operation; first as an integrated ice sheet with a broadly N-S orientated ice divide, and second as a multi-domed ice sheet orientated parallel with the shelf edge. A thick integrated ice sheet developed as ice expanded out of source areas in Scotland to envelop southerly ice caps in northern England and Wales, and connect with the Irish Ice Sheet to the west and the Scandinavian Ice Sheet across the North Sea. Following break-up of ice over the North Sea, ice streaming probably drove mass loss and ice-sheet thinning to create a more complex divide structure, where ice-flow patterns were largely controlled by the form of the underlying topography. Ice surface lowering occurred before separation of, and retreat to, multiple ice centres centred over high ground. We consider this 10-stage reconstruction of the evolution in ice-sheet configuration to be the simplest palaeo-glaciological interpretation of the flowsets identified from the geomorphological record and their relative timing. This empirically-based reconstruction of flow-pattern geometry provides a framework for more detailed local and regional studies and numerical modelling to provide robust explanations of the observed changes in ice-sheet structure in terms of climate and glacial dynamics. As a minimum, numerical model outputs should be able to reproduce the identified flowset patterns in space and satisfy their chronological order. © 2014 Elsevier Ltd.


Meland E.,University of Bergen
Scandinavian journal of public health | Year: 2010

AIMS: To clarify distributions of emotional and somatic symptoms among different groups involved in bullying behaviour during early adolescence; to explore differences in social integration and self-perceptions; to explore how different cut-off limits for bullying behaviour may affect the impact of these measures; and to interpret our findings in the light of theories of identity that may suggest directions for interventions against bullying in schools. METHODS: A cross-sectional study, based on self-completion questionnaire, of 1237 pupils aged 11-15 years in autumn 2000 in Alesund, Norway. RESULTS: Bullies and their victims reported similar and greater emotional impairments and psychosomatic complaints, lack of self-confidence, and pessimism than students not involved in bullying. With increasing involvement, bullies differed from non-involved students only in regard to depressive complaints and pessimism. The bullied group reported more depressive, somatic and anxiety complaints, and self-reproach with increasing victimisation. Both bullies and the bullied reported problems relating to school, parents, and teachers. Bullies enjoyed friendships to the same degree or better than their peers not involved in bullying, whereas the bullied group reported impaired peer relations and increasing problems with more serious involvement. Bullies, the bullied, and bully-victims reported diminishing peer support in their class with increasing involvement. CONCLUSIONS: Both the bullied and bullies share relational, emotional, and self-conceptual problems, but they also differ in whether they succeed in social arenas and to what extent they are affected by different emotional and self-conceptual problems. They are, however, fellow sufferers in many aspects.


Klanderud K.,Norwegian University of Life Sciences | Klanderud K.,University of Bergen
Journal of Ecology | Year: 2010

1. It is not clear how local and regional processes influence plant species recruitment. Local abiotic factors are predicted to constrain recruitment under harsh environmental conditions and low productivity, whereas the role of seed availability may be more important at intermediate productivity. The role of establishment limitation (local interactions) is predicted to increase under high productivity due to competition. 2. This study examined the effects of local biotic interactions, such as competition and facilitation from the resident vegetation, on alpine plant species recruitment, and investigated whether the role of species interactions depended on productivity. All naturally emerging seedlings were recorded in plots with intact vegetation and where vegetation had been removed, in a natural low-productivity alpine Dryas heath and in plots where productivity had increased after fertilizing. 3. Positive effects of vegetation removal on seedling emergence suggested that competition from neighbour vegetation may have an important role for recruitment in alpine plant communities. The role of competitive release increased with productivity. Productivity increased short-term, but not long-term seedling recruitment, likely due to increased competition from re-growth over time. There was no effect of productivity on species richness recovery after vegetation removal. 4. There was a positive relationship between neighbour species richness and seedling density in the low-productivity plots, but not in the high-productivity plots. Local seed production was the major seed source in both parts of the heath, but in the high-productivity plots, the high abundance of a few species in the species pool was more important for seedling recruitment than species richness. 5. Synthesis. Competition may play a significant role for plant species recruitment in environmentally harsh habitats of low productivity, where abiotic factors or facilitation traditionally are predicted to be more important ecological filters. Climate warming and increased nitrogen deposition may result in higher productivity of tundra plant communities, which may increase the role of competition, and the identity of neighbour species may become more important for recruitment than species richness. © 2010 The Author. Journal compilation © 2010 British Ecological Society.


Chapman E.W.,University of New Hampshire | Jorgensen C.,University of Bergen | Lutcavage M.E.,University of Massachusetts Amherst
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2011

The relationship between Atlantic bluefin tuna (ABFT, Thunnus thynnus) life history patterns and environmental conditions was investigated by developing a state-dependent model that optimizes energy allocation between growth and energy stores and the decision to spawn. The model successfully recreates growth, age-at-maturity, and seasonal variability in condition for western ABFT that spawn primarily in the Gulf of Mexico. Eastern ABFT spawning in the Mediterranean Sea display a life history trajectory shifted toward earlier maturation and, perhaps, reduced growth - a pattern predicted by the model when mortality was higher, migration distance shorter, and food intake during migration and spawning higher. Simulations highlight the sensitivity of the optimal ABFT life history strategy to variability in net energy intake, particularly during migration and spawning, a poorly understood component of their life cycle. Results also emphasize the importance for optimal life history patterns of the timing of spawning migrations in relation to the phenology and amplitude of seasonal prey availability. This study provides insight into potential mechanisms that underlie observations that are at the heart of current discussions regarding ABFT subpopulation structure and variable life history patterns.


Klove T.,University of Bergen | Lin T.-T.,National Chiao Tung University | Tsai S.-C.,National Chiao Tung University | Tzeng W.-G.,National Chiao Tung University
IEEE Transactions on Information Theory | Year: 2010

An (n,d) permutation array (PA) is a subset of S n with the property that the distance (under some metric) between any two permutations in the array is at least d They became popular recently for communication over power lines. Motivated by an application to flash memories, in this paper, the metric used is the Chebyshev metric. A number of different constructions are given, as well as bounds on the size of such PA. © 2010 IEEE.


Newell P.T.,Johns Hopkins University | Gjerloev J.W.,University of Bergen
Journal of Geophysical Research: Space Physics | Year: 2011

A generalization of the traditional 12-station auroral electrojet (AE) index to include more than 100 magnetometer stations, SME, is an excellent predictor of global auroral power (AP), even at high cadence (1 min). We use this index, and a database of more than 53,000 substorms derived from it, covering 1980-2009, to investigate time and energy scales in the magnetosphere, during substorms and otherwise. We find, contrary to common opinion, that substorms do not have a preferred recurrence rate but instead have two distinct dynamic regimes, each following a power law. The number of substorms recurring after a time Δt, N(Δt), varies as Δt-1.19 for short times (<80 min) and as Δt-1.76 for longer times (>3 hours). Other evidence also shows these distinct regimes for the magnetosphere, including a break in the power law spectra for SME at about 3 hours. The time between two consecutive substorms is only weakly correlated (r = 0.18 for isolated and r = 0.06 for recurrent) with the time until the next, suggesting quasiperiodicity is not common. However, substorms do have a preferred size, with the typical peak SME magnitude reaching 400-600 nT, but with a mean of 656 nT, corresponding to a bit less than 40 GW AP. More surprisingly, another characteristic scale exists in the magnetosphere, namely, a peak in the SME distribution around 61 nT, corresponding to about 5 GW precipitating AP. The dominant form of auroral precipitation is diffuse aurora; thus, these values are properties of the magnetotail thermal electron distribution. The characteristic 5 GW value specifically represents a preferred minimum below which the magnetotail rarely drops. The magnetotail experiences continuous loss by precipitation, so the existence of a preferred minimum implies driving that rarely disappears altogether. Finally, the distribution of SME values across all times, in accordance with earlier work on AE, is best fit by the sum of two distributions, each normal in log(SME). The lower distribution (with a 40% weighting) corresponds to the characteristic quiet peak, while the higher value distribution (60% weighting) is an average over the characteristic substorm peak and the subsequent prolonged recovery. Copyright 2011 by the American Geophysical Union.


Klove T.,University of Bergen
Designs, Codes, and Cryptography | Year: 2011

Lower bounds on the number of permutations p of {1, 2,⋯, n satisfying |p i - i| ≤ d for all i are given. © 2010 The Author(s).


Grimnes G.,University of Tromso | Figenschau Y.,University of Tromso | Almas B.,University of Bergen | Jorde R.,University of Tromso
Diabetes | Year: 2011

OBJECTIVE - Vitamin D deficiency is associated with an unfavorable metabolic profile in observational studies. The intention was to compare insulin sensitivity (the primary end point) and secretion and lipids in subjects with low and high serum 25(OH)D (25-hydroxyvitamin D) levels and to assess the effect of vitamin D supplementation on the same outcomes among the participants with low serum 25(OH)D levels. RESEARCH DESIGN AND METHODS - Participants were recruited from a population-based study (the Tromsø Study) based on their serum 25(OH)D measurements. A 3-h hyperglycemic clamp was performed, and the participants with low serum 25(OH)D levels were thereafter randomized to receive capsules of 20,000 IU vitamin D3 or identical-looking placebo twice weekly for 6 months. A final hyperglycemic clamp was then performed. RESULTS - The 52 participants with high serum 25(OH)D levels (85.6 ± 13.5 nmol/L [mean ± SD]) had significantly higher insulin sensitivity index (ISI) and lower HbA1c and triglycerides (TGs) than the 108 participants with low serum 25(OH)D (40.3 ± 12.8 nmol/L), but the differences in ISI and TGs were not significant after adjustments. After supplementation, serum 25(OH)D was 142.7 ± 25.7 and 42.9 ± 17.3 nmol/L in 49 of 51 completing participants randomized to vitamin D and 45 of 53 randomized to placebo, respectively. At the end of the study, there were no statistically significant differences in the outcome variables between the two groups. CONCLUSIONS - Vitamin D supplementation to apparently healthy subjects with insufficient serum 25(OH)D levels does not improve insulin sensitivity or secretion or serum lipid profile. © 2011 by the American Diabetes Association.


Haaheim L.R.,University of Bergen | Katz J.M.,Centers for Disease Control and Prevention
Influenza and other Respiratory Viruses | Year: 2011

The emergence of a novel swine-origin pandemic influenza virus in 2009, together with the continuing circulation of highly pathogenic avian H5N1 viruses and the urgent global need to produce effective vaccines against such public health threats, has prompted a renewed interest in improving our understanding of the immune correlates of protection against influenza. As new influenza vaccine technologies, including non-HA based approaches and novel production platforms are developed and undergo clinical evaluation, it has become clear that existing immune correlates such as serum hemagglutination-inhibition antibodies may be unsuitable to estimate vaccine immunogenicity and protective efficacy of such vaccines. This International Society for Influenza and other Respiratory Virus Diseases (ISIRV) sponsored international meeting held in Miami, Florida USA on March 1-3, 2010, brought together scientists from industry, academia, and government agencies that develop and evaluate seasonal and pandemic influenza vaccines and scientists from regulatory authorities that approve them, to identify approaches to develop expanded immune correlates of protection to aid in vaccine licensure. © 2011 Blackwell Publishing Ltd.


Bindoff L.A.,University of Bergen
Epilepsia | Year: 2011

The mitochondrial respiratory chain is the final common pathway for energy production. Defects affecting this pathway can give rise to disease that presents at any age and affects any tissue. However, irrespective of genetic defect, epilepsy is common and there is a significant risk of status epilepticus. We have studied two types of mitochondrial disease: one arising from a defect in mitochondrial DNA (mtDNA) (MELAS) and one due to a nuclear gene mutation (POLG). These two disorders show similarities in their clinicopathologic evolution and in findings in postmortem samples. Our findings based on antemortem magnetic resonance imaging (MRI) and postmortem studies suggest that the status epilepticus that is seen in both appears to be the result of cortical damage resulting from a common mechanism, namely energy failure. © Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.


Lorentzen R.J.,IRIS - International Research Institute of Stavanger | Flornes K.M.,IRIS - International Research Institute of Stavanger | Naevdal G.,University of Bergen
SPE Journal | Year: 2012

Even though the ensemble Kalman filter (EnKF) is widely used, history matching reservoirs with facies description has proven to be a major challenge. A preferred technique for estimating largescale facies fields within the petroleum industry is still missing. In this paper, we present a new approach to this problem. Instead of applying the EnKF directly to facies realizations, the approach applies a transformation of facies fields to a specific level-set function, representing distances between facies types. This ensures better agreement with the EnKF Gaussianity assumptions, and the method always returns facies realizations with geological authenticity. The method also offers large flexibility in generating the initial ensemble, which can be performed using any geostatistical tool. Furthermore, no modifications of the standard EnKF equations are needed. The methodology is evaluated on two synthetic examples with increasing complexity. In both examples, we consider reservoirs with channel structure. The results presented show that the updated models give large improvements in matching the measurements, and the uncertainty of the models is decreased. Further, recovery of the true petrophysical parameters is highly dependent on sufficient information in the measurements, but in one of the examples considered we are able to completely recover the true channel structure. Additional improvements in the quality of the updated facies fields are obtained by proper handling of the distances close to the reservoir boundaries, and by conditioning on specific statistical measures to better preserve prior information about channel properties. Copyright © 2012 Society of Petroleum Engineers.


Eckhoff R.K.,University of Bergen
Journal of Loss Prevention in the Process Industries | Year: 2014

BLEVEs remain a complex multi-faced phenomenon. The point of departure of the paper is the extensive review by Abbasi and Abbasi (2007), and the paper starts with presenting some deviating definitions and suggested characteristics of BLEVEs. Then a step-by-step description of the chain of events in typical BLEVEs follows. In most cases the first step will be that a vessel containing a gas that has been liquefied by pressurization (PLG) gets accidentally exposed to heat (most often a fire). The next step is that the vessel suddenly fails due to the increased internal vapour pressure and the weakening of the vessel material. The resulting very sudden depressurization of the hot liquid gives rise to intense, often volumetric, evaporation. The central role of the superheat limit temperature (SLT) of the liquid in the evaporation process is discussed. The very rapid evaporation in turn gives rise to powerful blast wave emission. If the evaporated liquid is combustible and gets ignited, a huge fireball will most often be generated. Properties and effects of fireballs from BLEVEs are discussed. The shattering of the initial vessel may cause propelling of high-speed missiles, which when hitting other PLG vessels may give rise to secondary BLEVEs. The remaining part of the combustible liquid from a BLEVEed vessel that has not evaporated will, when ignited, give rise to pool fires. Emission of toxic gases/vapours requires special actions. However, BLEVEs can also occur with non-toxic gases, and even in the absence of an initial fire. The induction time preceding a BLEVE is an important parameter, e.g. for the time available for rescue operations. Long-duration BLEVEs require special concerns. A part of the paper is devoted to various categories of BLEVE case histories. Available means for preventing process situations that can lead to BLEVEs are then discussed. If PLG-vessels get engulfed in fire measures for preventing catastrophic vessel failure may be activated. Finally measures for mitigating the consequences if BLEVEs do occur in spite of taking preventive measures are discussed. © 2014 Elsevier Ltd.


OBJECTIVE: Short endoscopic secretin tests for exocrine pancreatic function are not properly evaluated in cystic fibrosis (CF). METHODS: Patients with CF and healthy controls (HCs) underwent endoscopic collection of duodenal juice between 30 and 45 minutes after secretin stimulation. Duodenal juice was analyzed for HCO3 concentration and pancreatic enzyme activities. Stool was analyzed for fecal elastase. RESULTS: Thirty-one patients with CF and 25 HCs were tested. Patients were classified as exocrine pancreatic sufficient (n = 13) or insufficient (n = 18). Both bicarbonate concentrations and enzyme activities in duodenal juice differentiated patients with CFI from patients with CFS and HC (P < 0.001). The population displays strong correlation between severe CF genotype in both alleles and pancreatic insufficient phenotype (P < 0.001). CONCLUSIONS: Pancreatic exocrine insufficient CF patients could be differentiated from exocrine sufficient patients and HCs using short endoscopic secretin test.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially. © 2015 Wolters Kluwer Health, Inc. All rights reserved.


This article reviews the expanding body of literature that examines the mental health of HIV-affected children in sub-Saharan Africa. Focusing on primary research across disciplines and methodologies, the review examines the use of universalistic assumptions about childhood adversity and mental health in driving forward this body of research. Of the 31 articles identified for this review, 23 had a focus on the psychological distress experienced by HIV-affected children, while only 8 explored social psychological pathways to improved mental health, resilience and coping. The article argues that this preoccupation with pathology reflects global assemblages of definitions, understandings and practices that constitute the global mental health framework. While such a focus is useful for policy interventions and the mobilisation of resources to support children living in HIV-affected communities, it overshadows more culturally relevant and strengths-based conceptualisations of how mental health is understood and can be achieved in different parts of Africa. Furthermore, a continued focus on the psychological distress experienced by HIV-affected children runs the risk of medicalising their social experiences, which in turn may transform the social landscape in which children give meaning to loss and difficult experiences. The article concludes that mental health professionals and researchers need to take heed of the biopolitical implications of their work, and argues for more community-oriented and resilience-enhancing research that brings forward the voices of local people to inform interventions tackling the psychosocial challenges inevitably experienced by many children in sub-Saharan Africa. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.


Dettenrieder N.,University of Tubingen | Dietrich H.M.,University of Tubingen | Schadle C.,University of Tubingen | Maichle-Mossmer C.,University of Tubingen | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2012

Al B there for Lu: Boryllithium (THF) 2Li{B(NArCH) 2} (Ar=C 6H 3iPr 2-2,6) reacts with excess AlMe 3 to give dimeric {Me 2Al[B(NArCH) 2]} 2, which readily adds to [LnMe 3] n forming homoleptic Ln[AlMe 3B(NArCH) 2] 3 (Ln=Y, Lu, see picture). The reaction with [LnMe 3] n underlines the high methyl mobility and strong Al-B bonding in heteroleptic {Me 2Al[B(NArCH) 2]} 2, which is also evidenced by NMR spectroscopy. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Ueland P.M.,University of Bergen | Ulvik A.,Laboratoriebygget | Rios-Avila L.,University of Florida | Midttun O.,Laboratoriebygget | Gregory J.F.,University of Florida
Annual Review of Nutrition | Year: 2015

Measures of B6 status are categorized as direct biomarkers and as functional biomarkers. Direct biomarkers measure B6 vitamers in plasma-serum, urine and erythrocytes, and among these plasma pyridoxal 5′-phosphate (PLP) is most commonly used. Functional biomarkers include erythrocyte transaminase activities and, more recently, plasma levels of metabolites involved in PLP-dependent reactions, such as the kynurenine pathway, one-carbon metabolism, transsulfuration (cystathionine), and glycine decarboxylation (serine and glycine). Vitamin B6 status is best assessed by using a combination of biomarkers because of the influence of potential confounders, such as inflammation, alkaline phosphatase activity, low serum albumin, renal function, and inorganic phosphate. Ratios between substrate-products pairs have recently been investigated as a strategy to attenuate such influence. These efforts have provided promising new markers such as the PAr index, the 3-hydroxykynurenine:xanthurenic acid ratio, and the oxoglutarate:glutamate ratio. Targeted metabolic profiling or untargeted metabolomics based on mass spectrometry allow the simultaneous quantification of a large number of metabolites, which are currently evaluated as functional biomarkers, using data reduction statistics. Copyright ©2015 by Annual Reviews. All rights reserved.


Larsen B.,University of Bergen | Gudmundsson A.,University of London
Tectonophysics | Year: 2010

The permeability of many rocks, including many reservoirs, is mostly attributable to fractures that form interconnected clusters. Here we present the results of field studies and numerical models on the linkage of fractures, using primarily fractures in carbonate rocks from the UK. The numerical models focus on two fracture configurations: five offset fractures in a 5-layer model, and a single hydrofracture in a 3-layer model. In some of the 3-layer models, a weak, open contact is added between the two topmost layers. In the 5-layer models loading is by 5. MPa tensile stress, whereas the 3-layer models the only loading is the internal fluid overpressure of 6. MPa in the hydrofracture itself, located in the lowermost of the three layers. For the 5-layer models, tensile stresses occur between the nearby tips of the offset fracture pairs, but these stresses are generally too low in the soft shale layers to initiate fractures. The tensile stresses, however, commonly concentrate at the contacts between the shale and limestone layers and may therefore result in delamination (debonding), that is, opening of the contacts. By contrast, the shear stresses between the nearby tips of the fracture pairs are often high enough to generate shear or mixed-mode fractures that connect the nearby tips of the original offset fractures, resulting in clusters that can conduct fluids. For the 3-layer models, the fracture-induced tensile stresses in the uppermost layer are suppressed by a comparatively thick compliant (shale) layer and/or the weak, open contact. Thus, no fracture formation is possible in that layer but at their contacts with the compliant layer the hydrofracture apertures increase. Thus, a compliant layer may arrest the vertical hydrofracture propagation from its stiff host layer but, at the same time, increase its maximum aperture and encourage lateral fluid transport at the layer contact between the layers. © 2010 Elsevier B.V.


Four non-iterative parameter estimation methods, applying four different ways to assimilate data, are compared to the (iterative) randomized maximum likelihood (RML) method on problems where the forward model is weakly nonlinear and simplistic. Both original and slightly modified versions of established data assimilation methods used for reservoir history matching are considered. Within the Gauss-linear regime, these methods are equivalent in the sense that they all sample correctly from the posterior pdf. The modification consists of replacing the global Kalman gain by a local gain similar to the one applied with RML. This modification, and the simplicity of the forward model considered, allows for asymptotic calculations, correct to lowest order in the quantity controlling the forward-model nonlinearity, to be performed for the non-iterative methods as well as for RML. Comparison of the resulting asymptotic parameter estimates explicitly reveals interesting relations between different ways to assimilate data, that goes beyond the Gauss-linear regime. Results from extensive numerical experiments with the modified methods and with the original methods support the asymptotic results when considering the mean results over a large number of randomized experimental settings where also the forward models vary. For randomized experiments with fixed forward model settings, trends from the asymptotic results were not visible in the numerical results. Although the nonlinear forward models considered are not closely related to reservoir models, the knowledge obtained should be useful also when the latter type of models are considered. © 2015, Springer International Publishing Switzerland.


Schwinger C.,Center for International Health | Fadnes L.T.,Center for International Health | Fadnes L.T.,University of Bergen | Van Den Broeck J.,Center for International Health
American Journal of Clinical Nutrition | Year: 2016

Background: Growth assessment based on the WHO child growth velocity standards can potentially be used to predict adverse health outcomes. Nevertheless, there are very few studies on growth velocity to predict mortality. Objectives: We aimed to determine the ability of various growth velocity measures to predict child death within 3 mo and to compare it with those of attained growth measures. Design: Data from 5657 children <5 y old who were enrolled in a cohort study in the Democratic Republic of Congo were used. Children were measured up to 6 times in 3-mo intervals, and 246 (4.3%) children died during the study period. Generalized estimating equation (GEE) models informed the mortality risk within 3 mo for weight and length velocity z scores and 3-mo changes in midupper arm circumference (MUAC). We used receiver operating characteristic (ROC) curves to present balance in sensitivity and specificity to predict child death. Results: GEE models showed that children had an exponential increase in the risk of dying with decreasing growth velocity in all 4 indexes (1.2- to 2.4-fold for every unit decrease). A length and weight velocity z score of <23 was associated with an 11.8- and a 7.9-fold increase, respectively, in the RR of death in the subsequent 3-mo period (95% CIs: 3.9, 35.5, and 3.9, 16.2, respectively). Weight and length velocity z scores had better predictive abilities [area under the ROC curves (AUCs) of 0.67 and 0.69] than did weight-for-age (AUC: 0.57) and length-for-age (AUC: 0.52) z scores. Among wasted children (weight-for-height z score <22), the AUC of weight velocity z scores was 0.87. Absolute MUAC performed best among the attained indexes (AUC: 0.63), but longitudinal assessment of MUAC-based indexes did not increase the predictive value. Conclusion: Although repeated growth measures are slightly more complex to implement, their superiority in mortality-predictive abilities suggests that these could be used more for identifying children at increased risk of death.


Gold C.,University of Bergen | Erkkila J.,University of Jyvaskyla | Crawford M.J.,Imperial College London
Acta Psychiatrica Scandinavica | Year: 2012

Objective: Randomised controlled trials (RCTs) aim to provide unbiased estimates of treatment effects. However, the process of implementing trial procedures may have an impact on the performance of complex interventions that rely strongly on the intuition and confidence of therapists. We aimed to examine whether shifting effects over the recruitment period can be observed that might indicate such impact. Method: Three RCTs investigating music therapy vs. standard care were included. The intervention was performed by experienced therapists and based on established methods. We examined outcomes of participants graphically, analysed cumulative effects and tested for differences between first vs. later participants. We tested for potential confounding population shifts through multiple regression models. Results: Cumulative differences suggested trends over the recruitment period. Effect sizes tended to be less favourable among the first participants than later participants. In one study, effects even changed direction. Age, gender and baseline severity did not account for these shifting effects. Conclusion: Some trials of complex interventions have shifting effects over the recruitment period that cannot be explained by therapist experience or shifting demographics. Replication and further research should aim to find out which interventions and trial designs are most vulnerable to this new kind of performance bias. © 2012 John Wiley & Sons A/S.


Archard G.A.,Pennsylvania State University | Braithwaite V.A.,University of Bergen
Journal of Zoology | Year: 2010

Animal temperament describes behavioural differences between individuals that are consistent across time and contexts. Variation in animal temperament is rapidly gaining interest and attention within behavioural and evolutionary ecology. If we are to understand the causes and consequences of temperament variation within and between populations we need to determine the selection pressures that affect temperament in natural environments. To date, however, the vast majority of temperament studies have been carried out on captive-bred individuals. This review highlights potential problems that arise from using captive animals to elucidate the ecological and evolutionary functions of temperament in wild populations. For example, development, learning and environmental variability can all affect behaviour. Thus, both environment and gene-by environment interactions can affect the fitness functions of different temperaments, and hence selection. We stress the need for measurements of repeatability and heritability, and the importance of biological and ecological validation of temperament tests in wild animals. We describe the limited evidence from wild populations of the fitness consequences of temperament variation, and the use of intra- and inter-specific comparisons to prove adaptation. To identify multiple axes of behavioural variation, and how these interact with environments that vary spatially and temporally, we need long-term studies on wild populations - yet few studies of this nature currently exist. Finally, and perhaps counter-intuitively, we suggest that there is much to be gained from incorporating some of the approaches and statistics employed in the much longer established field of human personality. © 2010 The Authors. Journal compilation © 2010 The Zoological Society of London.


Gjengedal H.,University of Bergen
The International journal of prosthodontics | Year: 2012

This study compared the dietary intake of edentulous subjects dissatisfied with their existing mandibular complete dentures following two different prosthodontic management interventions. A convenience sample of 60 subjects was randomly allocated into two equal treatment modalities: relined conventional denture (RCD) or converted implant-retained overdenture (IOD). Two-year data incorporating demographics and food avoidance were recorded using a self-administered questionnaire at baseline and regular follow-up intervals. Twenty-four-hour dietary intake assessments were obtained by telephone interviews at three spaced intervals. Dietary analyses were based on nutrient values from the Norwegian Food Composition Table. Twenty-seven patients in the IOD group and 26 in the RCD group completed the protocol. There were no statistical differences regarding dietary intake and energy distribution. Intake of protein and fat, especially saturated fat, were above Nordic recommendations, and carbohydrate intake was below. Vitamin D intake was at the recommended level, but that of vitamin C, folate, and fiber were lower than recommended. The IOD group reported significantly less avoidance of certain food items at 3 and 24 months (P < .001), better chewing ability (P < .001), and greater willingness to eat more of some food items (P < .001). There were no significant differences regarding food choices and nutrient intake between the IOD and RCD groups. However, the IOD group reported significantly better chewing ability, less food avoidance, and greater willingness to eat more of certain food items.


Lonning P.E.,University of Bergen
Therapeutic Advances in Medical Oncology | Year: 2012

Use of chemotherapy for patients with estrogen receptor (ER)-positive breast cancer has been a conflicting issue. Recent studies have identified predictive markers allowing identification of poor-prognosis ER-positive breast cancers in need of more aggressive therapy. In general, tumours belonging to the so-called luminal B class, tumours expressing a high Ki67, human epidermal growth factor receptor 2 (HER-2) overexpression or a high score on the Oncotype DX gene expression profile reveal a poor prognosis compared with ER-rich tumours of the luminal A class. In contrast, recent studies have shown these tumours, contrasting tumours of the luminal A class, to benefit from more aggressive anthracycline-containing chemotherapy including a taxane. In the case of metastatic disease, patients with HER-2-positive, ER-positive tumours may benefit from having endocrine therapy and an anti-HER-2 agent administered in combination. © The Author(s), 2012.


Skar R.,University of Bergen
Journal of Clinical Nursing | Year: 2010

Aim: To illuminate the meaning of nurses' experiences of autonomy in work situations. Background: Professional autonomy means having the authority to make decisions and the freedom to act in accordance with one's professional knowledge base. An understanding of autonomy is needed to clarify and develop the nursing profession in rapidly changing health care environments and internationally there is a concern about how the core elements of nursing are taken care of when focusing on expansion and extension of specialist nursing roles. Design: Qualitative study. Methods: This paper reports part of a project aimed at exploring the education and work qualifications required by the nursing profession. Eleven Norwegian nurses, each with 2-3 years of work experience since graduation, participated in both in-depth interviews and focus group interviews in 2006. A qualitative hermeneutic approach, inspired by Gadamer's philosophy, guided the research process and the analysis and interpretation of the transcribed interview-texts. Results: The nurses' descriptions of their experiences of autonomy in work situations emerged as four themes: 'to have a holistic view', 'to know the patient', 'to know that you know' and 'to dare'. To be knowledgeable and confident was found to be the coherent meaning of autonomy in nursing practice. Conclusions: Authority of total patient care, the power to make decisions in a relationship with the patient and next of kin and the freedom to make clinical judgements, choices and actions seem to be connected to the meaning of autonomy in nursing practice. Relevance to clinical practice: To gain autonomous practice, nurses must be competent and have the courage to take charge in situations where they are responsible. This study shows the challenges in handling this autonomous practice. © 2009 Blackwell Publishing Ltd.


Bell R.F.,University of Bergen
Cochrane database of systematic reviews (Online) | Year: 2012

This is an update of the original review published in Issue 1, 2003. Ketamine is a commonly used anaesthetic agent, and in subanaesthetic doses is also given as an adjuvant to opioids for the treatment of cancer pain, particularly when opioids alone prove to be ineffective. Ketamine is known to have psychotomimetic (including hallucinogenic), urological and hepatic adverse effects. To determine the effectiveness and adverse effects of ketamine as an adjuvant to opioids in the treatment of cancer pain. Studies were originally identified from MEDLINE (1966 to 2002), EMBASE (1980 to 2002), CancerLit (1966 to 2002), The Cochrane Library (Issue 1, 2001); by handsearching reference lists from review articles, trials, and chapters from standard textbooks on pain and palliative care. The manufacturer of ketamine (Pfizer Parke-Davis) provided search results from their in-house database, PARDLARS.An improved and updated search of the following was performed in May 2012: CENTRAL, MEDLINE & OVID MEDLINE R, EMBASE. Randomized controlled trials (RCTs) of adult patients with cancer and pain being treated with an opioid, and receiving either ketamine (any dose and any route of administration) or placebo or an active control. Studies having a group size of at least 10 participants who completed the trial. Two independent review authors identified four RCTs for possible inclusion in the review, and 32 case studies/case series reports. Quality and validity assessment was performed by three independent review authors, and two RCTs were excluded because of inappropriate study design. Patient-reported pain intensity and pain relief was assessed using visual analogue scales (VAS), verbal rating scales or other validated scales, and adverse effects data were collated. For the update three RCTs were identified for possible inclusion in the review. Three new studies were identified by the updated search. All three were excluded from the review. Two studies were eligible for inclusion in the original review and both concluded that ketamine improves the effectiveness of morphine in the treatment of cancer pain. However, pooling of the data was not appropriate because of the small total number of participants (30), and the presence of clinical heterogeneity. Some patients experienced hallucinations on both ketamine plus morphine and morphine alone and were treated successfully with diazepam. No other serious adverse effects were reported. Since the last version of this review three new studies were identified but excluded from the review. Current evidence is insufficient to assess the benefits and harms of ketamine as an adjuvant to opioids for the relief of cancer pain. More RCTs are needed.


Morken N.-H.,University of Bergen
European Journal of Obstetrics Gynecology and Reproductive Biology | Year: 2011

Objectives: To assess the risk of spontaneous and iatrogenic preterm delivery in singleton pregnancies when comparing in vitro fertilization (IVF) pregnancies with intracytoplasmic sperm injection (ICSI) pregnancies. Study design: A national population-based cohort study using Norwegian Medical Birth Register data during 1999 through 2006 was designed. The cohort included 5824 singleton pregnancies after IVF and ICSI treatment. Multinomial logistic regression analyses were used to calculate risk estimates. Results: There were no differences in maternal complicating factors such as pre-eclampsia, hypertension and diabetes between the IVF and ICSI pregnancies. However, IVF pregnancies had a 60% increased risk of moderately (32+0days-36+6days gestational weeks) iatrogenic preterm delivery (OR: 1.6, 95%CI: 1.1-2.2) and a 40% increased risk of iatrogenic preterm delivery <37 weeks (OR: 1.4, 95%CI: 1.02-1.9) compared to ICSI pregnancies. Conclusion: IVF pregnancies were at increased risk of moderately iatrogenic preterm delivery when compared to ICSI pregnancies. © 2010 Elsevier Ireland Ltd. All rights reserved.


Bjorknes R.,University of Oslo | Manger T.,University of Bergen
Prevention Science | Year: 2013

A randomized prevention study for ethnic minority mothers assessed the intervention effects of Parent Management Training-Oregon Model (PMTO) on maternal parent practices and child behavior. Ninety-six mothers from Somalia and Pakistan and their children aged 3 to 9 years were randomized to PMTO or a wait-list condition (WLC). Assessments were carried out at the baseline and post-intervention, using standardized measures and a multi-agent approach. All analyses were based on the intention-to-treat principle. Analysis of covariance (ANCOVA) showed that PMTO was effective in enhancing parent practices, with a decrease in harsh discipline and an increase in positive parenting. Moreover, PMTO produced reductions in motherreported child conduct problems. The largest effect sizes were found among mothers who attended more than 50 % of the PMTO group sessions. Teacher reports showed, however, that there were no significant intervention effects on conduct problems and social competence in kindergarten or school. The results emphasize the importance and feasibility of offering PMTO to ethnic minority families. © 2012 Society for Prevention Research.


Rosnes E.,University of Bergen | Graell I Amat A.,Chalmers University of Technology
IEEE Transactions on Information Theory | Year: 2011

In this work, we consider the minimum distance properties and convergence thresholds of 3-D turbo codes (3D-TCs), recently introduced by Berrou Here, we consider binary 3D-TCs while the original work of Berrou considered double-binary codes. In the first part of the paper, the minimum distance properties are analyzed from an ensemble perspective, both in the finite-length regime and in the asymptotic case of large block lengths. In particular, we analyze the asymptotic weight distribution of 3D-TCs and show numerically that their typical minimum distance dmin may, depending on the specific parameters, asymptotically grow linearly with the block length, i.e., the 3D-TC ensemble is asymptotically good for some parameters. In the second part of the paper, we derive some useful upper bounds on the dmin when using quadratic permutation polynomial (QPP) interleavers with a quadratic inverse. Furthermore, we give examples of interleaver lengths where an upper bound appears to be tight. The best codes (in terms of estimated dmin ) obtained by randomly searching for good pairs of QPPs for use in the 3D-TC are compared to a probabilistic lower bound on the dmin when selecting codes from the 3D-TC ensemble uniformly at random. This comparison shows that the use of designed QPP interleavers can improve the dmin significantly. For instance, we have found a (6144,2040) 3D-TC with an estimated dmin of 147, while the probabilistic lower bound is 69. Higher rates are obtained by puncturing nonsystematic bits, and optimized periodic puncturing patterns for rates 1/2, 2/3, and 4/5 are found by computer search. Finally, we give iterative decoding thresholds, computed from an extrinsic information transfer chart analysis, and present simulation results on the additive white Gaussian noise channel to compare the error rate performance to that of conventional turbo codes. © 2011 IEEE.


Mitternacht S.,University of Bergen
F1000Research | Year: 2016

Calculating solvent accessible surface areas (SASA) is a run-of-the-mill calculation in structural biology. Although there are many programs available for this calculation, there are no free-standing, open-source tools designed for easy tool-chain integration. FreeSASA is an open source C library for SASA calculations that provides both command-line and Python interfaces in addition to its C API. The library implements both Lee and Richards' and Shrake and Rupley's approximations, and is highly configurable to allow the user to control molecular parameters, accuracy and output granularity. It only depends on standard C libraries and should therefore be easy to compile and install on any platform. The library is well-documented, stable and efficient. The command-line interface can easily replace closed source legacy programs, with comparable or better accuracy and speed, and with some added functionality. © 2016 Mitternacht S.


Wang W.,University of Bergen | Arne Sande S.,University of Oslo
European Polymer Journal | Year: 2014

We report a study where we follow a chemical crosslinking process and record the intensity autocorrelation functions for two polymer systems, hydroxyethylcellulose (HEC) and hydrophobically modified hydroxyethylcellulose (HMHEC), by dynamic light scattering (DLS). Due to the distinct chemical structures, the measured intensity autocorrelation function shows significant difference between the two systems. Two relaxation modes were found for both systems, which were attributed to the cooperative relaxation and the structural relaxation. The decay rate for cooperative diffusion was found to decrease during the gelation for HEC, but it remains constant for HMHEC. The same trend was found for the structural relaxation where the decay rate decreased as a function of the gelation time for HEC, but not for HMHEC. By analyzing the amplitudes of both relaxation modes, we also found that during the gelation the structural relaxation was suppressed, which was caused by the decrease of the elastic modulus. © 2014 Elsevier Ltd. All rights reserved.


Levi T.,University of California at Santa Cruz | Kilpatrick A.M.,University of California at Santa Cruz | Mangel M.,University of Bergen | Mangel M.,University of California at Santa Cruz | Wilmers C.C.,University of California at Santa Cruz
Proceedings of the National Academy of Sciences of the United States of America | Year: 2012

Lyme disease is the most prevalent vector-borne disease in North America, and both the annual incidence and geographic range are increasing. The emergence of Lyme disease has been attributed to a century-long recovery of deer, an important reproductive host for adult ticks. However, a growing body of evidence suggests that Lyme disease risk may now be more dynamically linked to fluctuations in the abundance of small-mammal hosts that are thought to infect the majority of ticks. The continuing and rapid increase in Lyme disease over the past two decades, long after the recolonization of deer, suggests that other factors, including changes in the ecology of small-mammal hosts may be responsible for the continuing emergence of Lyme disease.We present a theoretical model that illustrates how reductions in small-mammal predators can sharply increase Lyme disease risk. We then show that increases in Lyme disease in the northeastern and midwestern United States over the past three decades are frequently uncorrelated with deer abundance and instead coincide with a range-wide decline of a key small-mammal predator, the red fox, likely due to expansion of coyote populations. Further, across four states we find poor spatial correlation between deer abundance and Lyme disease incidence, but coyote abundance and fox rarity effectively predict the spatial distribution of Lyme disease in NewYork. These results suggest that changes in predator communities may have cascading impacts that facilitate the emergence of zoonotic diseases, the vast majority of which rely on hosts that occupy low trophic levels.


Csernai L.P.,University of Bergen | Eyyubova G.,University of Oslo | Eyyubova G.,Moscow State University | Magas V.K.,University of Barcelona
Physical Review C - Nuclear Physics | Year: 2012

It has been shown in recent ALICE@LHC measurements that the odd flow harmonics, in particular, a directed flow v 1, occurred to be weak and dominated by random fluctuations. In this work we propose a new method, which makes the measurements more sensitive to the flow patterns showing global collective symmetries. We demonstrate how the longitudinal center of mass rapidity fluctuations can be identified, and then the collective flow analysis can be performed in the event-by-event center of mass frame. Such a method can be very effective in separating the flow patterns originating from random fluctuations, and the flow patterns originating from the global symmetry of the initial state. © 2012 American Physical Society.


Ershov S.N.,Joint Institute for Nuclear Research | Vaagen J.S.,University of Bergen | Zhukov M.V.,Chalmers University of Technology
Physical Review C - Nuclear Physics | Year: 2012

An unusually large value of the 22C matter radius has recently been extracted from measured reaction cross sections. The giant size can be explained by a very loose binding that is, however, not known experimentally yet. Within the three-body cluster model we have explored the sensitivity of the s-motion-dominated 22C geometry to the two-neutron separation energy. A low energy of a few tens of keV is required to reach the alleged experimental lower value of the matter radius, while the experimental mean radius requires an extremely tiny binding. The dependence of the 22C charge radius on the two-neutron separation energy is also presented. The soft dipole mode in 22C is shown to be strongly affected by the loose binding and should be studied in the process of Coulomb fragmentation. © 2012 American Physical Society.


Helland-Hansen W.,University of Bergen | Helland-Hansen W.,University Center in Svalbard
Sedimentology | Year: 2010

Textural and mineralogical properties of the sediment, facies characteristics (both derived from well data), stacking patterns (derived from well and seismic data) and plan-view shapes (derived from seismic data) are all essential components when reconstructing reservoir geometries from subsurface data sets. Without the availability of all these sources of information, reservoir predictions can potentially deviate significantly from the true geometries. In particular, inferences about internal sandbody geometry from plan-view considerations (isopach maps and seismic attribute maps) may lead to erroneous conclusions without knowledge of facies and textural properties of the sediment. Analysis of well-exposed sedimentary systems has the potential to establish links between internal facies characteristics and large-scale geometry and to improve models coupling information at these variable scales. The Palaeogene Battfjellet Formation, Svalbard, has been studied with the aim to unravel internal characteristics and external form by investigating sediment properties, facies and stacking patterns. The formation shows a combination of texturally and mineralogically very immature sediments, a predominance of wave-generated or wave-induced sedimentary structures and a stacking pattern of highly variable numbers of parasequences at localities few kilometres apart that best can be explained in terms of small shifting deltaic lobes that produced a complex pattern of overlapping sandbodies. The strong evidence of wave action in the receiving basin could in itself indicate strike-extensive sandstone bodies; however, the complex sandbody arrangement and the immaturity of the sediments preclude such an interpretation. Traditional facies models coupling plan-view geometries with internal facies characteristics (such as the coupling of strike extensive barrier systems with wave-dominated sedimentary structures or the coupling of elongated fluvial-dominated deltas with offshore-directed current-generated structures) are much too simple and may lead to erroneous interpretations if the complexity revealed by all sources of data is not appreciated. © 2009 The Author. Journal compilation © 2009 International Association of Sedimentologists.


Dilek Y.,Miami University Ohio | Furnes H.,University of Bergen
Elements | Year: 2014

Ophiolites are suites of temporally and spatially associated ultramafic, mafic, and felsic rocks that are interpreted to be remnants of ancient oceanic crust and upper mantle. Ophiolites show significant variations in their internal structure, geochemical fingerprints, and emplacement mechanisms. These differences are controlled by (1) the proximity, when formed at the magmatic stage, to a plume or trench; (2) the rate, geometry, and nature of ocean-ridge spreading; (3) mantle composition, temperature, and fertility; and (4) the availability of fluids. The oceanic crust preserved in ophiolites may form in any tectonic setting during the evolution of ocean basins, from the rift-drift and seafloor spreading stages to subduction initiation and terminal closure. An ophiolite is emplaced either from downgoing oceanic lithosphere via subduction-accretion or from the upper plate in a subduction zone through trench-continent collision. Subduction zone tectonics is thus the most important factor in the igneous evolution of ophiolites and their emplacement into continental margins.


Gjerloev J.W.,University of Bergen | Gjerloev J.W.,Johns Hopkins University
Journal of Geophysical Research: Space Physics | Year: 2012

In this paper I outline the data processing technique which is used in the SuperMAG initiative. SuperMAG is a worldwide collaboration of organizations and national agencies that currently operate more than 300 ground based magnetometers. SuperMAG provides easy access to validated ground magnetic field perturbations in the same coordinate system, identical time resolution and with a common baseline removal approach. The purpose of SuperMAG is to provide scientists, teachers, students and the general public easy access to measurements of the magnetic field at the surface of the Earth. Easy access to data, plots and derived products maximizes the utilization of this unique data set. It is outlined how SuperMAG processes the observations obtained by the individual data provider. Data are rotated into a local magnetic coordinate system by determining a time dependent declination angle. This angle displays a slow gradual change and a yearly periodic variation attributed to changes in the Earth main field and season temperature variations. The baseline is determined from the data itself in a three step process: (1) a daily baseline, (2) a yearly trend, and (3) a residual offset. This technique does not require so-called quiet days and thus it avoids all the well-known problems associated with their identification. The residual offset for the N- and Z-components shows a distinct latitudinal dependence while the E-component is independent of the latitude. This result is interpreted as being due to a weak ring current (likely asymmetric) which is present even during official quiet days. For the purpose of M-I research using 1-min data I find no difference between observatories and variometers. I finally argue that there is no correct baseline determination technique since we do not have a set of ground-truth observations required to make an objective evaluation. Instead, the user must keep in mind the assumptions on which the baseline was determined and draw conclusions accordingly. © 2012. American Geophysical Union. All Rights Reserved.


To compare the effect of modified constraint-induced movement therapy (mCIMT) to bimanual task-related training for patients in the subacute phase post stroke. A single-blinded randomized controlled trial. Inpatient and outpatient rehabilitation clinics and the patient's home. Thirty patients in the subacute phase post stroke (2-16 weeks) were randomized to modified constraint-induced movement therapy with an emphasis on unimanual tasks, or bimanual task-related training, emphasizing bimanual tasks. All trained with a therapist 4 hours a week for four weeks, followed by a 2-3 hours daily self-training program. Patients in the modified constraint-induced movement therapy group were supposed to wear a restraining mitt on the unaffected hand for 4 hours a day for four weeks. Blinded assessments at pre and post treatment and after three months with Action Research Arm Test as a primary outcome measure, Nine-Hole Peg Test and Motor Activity Log. Power calculations suggested an inclusion of 60 patients, but due to recruitment difficulties the trial was stopped after an interim analysis at 30 patients. There was no difference in change (P > 0.05) between the groups on any of the measures, neither at post treatment nor at follow-up assessments. From pre-intervention to follow-up assessment the modified constraint-induced movement therapy group obtained a mean change score of 17.77 (14.66) on Action Research Arm Test, the bimanual group 15.47 (13.59). Bimanual training was as effective as modified constraint-induced movement therapy in improving arm motor function. Wearing a mitt seems unnecessary for most patients in the subacute phase post stroke when focused affected arm training is provided.


Ebbesson L.O.E.,University of Bergen | Braithwaite V.A.,Pennsylvania State University
Journal of Fish Biology | Year: 2012

Most fishes experiencing challenging environments are able to adjust and adapt their physiology and behaviour to help them cope more effectively. Much of this flexibility is supported and influenced by cognition and neural plasticity. The understanding of fish cognition and the role played by different regions of the brain has improved significantly in recent years. Techniques such as lesioning, tract tracing and quantifying changes in gene expression help in mapping specialized brain areas. It is now recognized that the fish brain remains plastic throughout a fish's life and that it continues to be sensitive to environmental challenges. The early development of fish brains is shaped by experiences with the environment and this can promote positive and negative effects on both neural plasticity and cognitive ability. This review focuses on what is known about the interactions between the environment, the telencephalon and cognition. Examples are used from a diverse array of fish species, but there could be a lot to be gained by focusing research on neural plasticity and cognition in fishes for which there is already a wealth of knowledge relating to their physiology, behaviour and natural history, e.g. the Salmonidae. © 2012 The Fisheries Society of the British Isles.


Kolstad J.R.,University of Bergen | Kolstad J.R.,Chr Michelsen Institute
Health Economics | Year: 2011

The geographical imbalance of the health workforce in Tanzania represents a serious problem when it comes to delivering crucial health services to a large share of the population. This study provides new quantitative information about how to make jobs in rural areas more attractive to newly educated clinical officers (COs). A unique data set stemming from a discrete choice experiment with CO finalists in Tanzania is applied. The results show that offering continuing education after a certain period of service is one of the most powerful recruitment instruments the authorities have available. Increased salaries and hardship allowances will also substantially increase recruitment in rural areas. Offers of decent housing and good infrastructure, including the provision of equipment, will increase recruitment to rural remote areas but not as much as higher wages and offers of education. Women are less responsive to pecuniary incentives and are more concerned with factors that directly allow them to do a good job, while those with parents living in a remote rural area are generally less responsive to the proposed policies. When the willingness to help other people is a strong motivating force, policies that improve the conditions for helping people appear particularly effective. Copyright © 2010 John Wiley & Sons, Ltd.


Newell P.T.,Johns Hopkins University | Gjerloev J.W.,University of Bergen
Journal of Geophysical Research: Space Physics | Year: 2012

Using the extensive set of stations in the SuperMAG collaboration, we introduce partial ring current indices, which provide new insights into ring current development. The indices are labeled SMR-00, SMR-06, SMR-12 and SMR-18 for their center local time range. These indices incorporate data from 98 mid and low latitude stations. The behavior of these local time indices during storms and substorms, on both an individual and superposed epoch basis, produces consistent patterns. The initial positive spike before a storm, which results from solar wind pressure enhancements, is seen simultaneously at all local times. Once the main phase of the storm begins, however, SMR-18 nearly always drops fastest and furthest in magnitude, while SMR-06 drops more slowly (i.e., has weaker ring current signatures), and never as far. Symmetry is, in fact, not reached until storm recovery is well underway, with a typical symmetry point of about 20-25 h after onset. If the main phase continues to new depths (larger magnitude negative SMR) over a longer time period, the SMR-18 sector will continue to lead, and SMR-06 to lag. There has been controversy over the extent to which substorm auroral and cross-tail currents perturb Dst and SYM-H signatures. The signature of substorms can be seen very clearly as a positive spike of roughly 10 nT magnitude in SMR-00, and only to a much lesser extent elsewhere. The SMR global index, and thus also SYM-H, experiences only a small immediate perturbation from a substorm onset, ending with a net drop of a few nT. Since there are typically only 1-2 substorms in a main phase, substorms are a minor factor in the development of the storm time ring current. Indeed, because even the peak perturbation of substorms currents in the most affected sector (which is midnight) is nearly an order of magnitude smaller than the storm perturbation (about 10 nT versus 80 nT), fluctuations in the cross-tail and field-aligned currents in general are not a major influence over SMR. The pattern of LT substorm responses, with a strong positive SMR-00 effect, weak positive SMR-06 effect, and negative SMR-18 effect implies it is field-aligned currents and not the cross-tail currents which create modest perturbations in the putatively ring current indices. Copyright 2012 by the American Geophysical Union.


Jordal B.H.,University of Bergen | Cognato A.I.,Michigan State University
BMC Evolutionary Biology | Year: 2012

Background: Fungus farming is an unusual life style in insects that has evolved many times in the wood boring weevils named ambrosia beetles. Multiple occurrences of this behaviour allow for a detailed comparison of the different origins of fungus farming through time, its directionality, and possible ancestral states. We tested these hypotheses with a phylogeny representing the largest data set to date, nearly 4 kb of nucleotides from COI, EF-1, CAD, ArgK, 28S, and 200 scolytine taxa. Results: Phylogenetic analyses using Bayesian or parsimony approaches placed the root of Scolytinae close to the tribe Scolytini and Microborus, but otherwise indicated low resolution at older nodes. More recent clades were well resolved, including ten origins of fungus farming. There were no subsequent reversals to bark or phloem feeding in the fungus farming clades. The oldest origin of fungus farming was estimated near 50 Ma, long after the origin of Scolytinae (100-120 Ma). Younger origins included the species rich Xyleborini, dated to 21 Ma. Sister group comparisons and test of independence between traits indicated that neither gregarious larval feeding nor regular inbreeding by sibling mating was strongly correlated with the origin of fungus farming. Conclusion: Origins of fungus farming corresponded mainly with two periods of global warming in the Cenozoic era, which were characterised by broadly distributed tropical forests. Hence, it seems likely that warm climates and expanding tropical angiosperm forests played critical roles in the successful radiation of diverse fungus farming groups. However, further investigation will likely reveal additional biological factors that promote fungus farming. © 2012 Jordal and Cognato; licensee BioMed Central Ltd.


Klove T.,University of Bergen
Cryptography and Communications | Year: 2016

The concepts of a linear covering code and a covering set for the limited-magnitude-error channel were introduced in Kløve and Schwartz (2013). Here, a number of new covering set constructions are given, in particular for sets of r-tuples of large r. The main emphasis is on errors of size up to three. © 2015, Springer Science+Business Media New York.


Hirschfield G.M.,University of Birmingham | Karlsen T.H.,University of Oslo | Karlsen T.H.,University of Bergen | Lindor K.D.,Arizona State University | Adams D.H.,University of Birmingham
The Lancet | Year: 2013

Primary sclerosing cholangitis is the classic hepatobiliary manifestation of inflammatory bowel disease and is generally chronic and progressive. Patients frequently present with asymptomatic, anicteric cholestasis, but many develop progressive biliary strictures with time, leading to recurrent cholangitis, biliary cirrhosis, and end-stage liver disease. Medical treatment does not slow the progression of disease, and many patients need liver transplantation, after which recurrent disease is a risk. The increased incidence of hepatobiliary cancer, which is not related to the underlying severity of biliary fibrosis, is of particular concern. Risk of colorectal cancer is also increased in patients with coexistent inflammatory bowel disease. Mechanistic insights have arisen from studies of secondary sclerosing cholangitis, in which a similar clinical profile is associated with a specific cause, and genomic studies have elucidated potential disease-initiating pathways in the primary form. The close association between inflammatory bowel disease and primary sclerosing cholangitis underscores the need to further understand the role of environmental factors in generation of lymphocytes that are postulated to be retargeted, deleteriously, to the biliary tree. Treatment of primary sclerosing cholangitis is confined to supportive measures, but advances in pathobiology suggest that new stratified approaches will soon be available.


Overmier J.B.,University of Minnesota | Murison R.,University of Bergen
Applied Psychology: Health and Well-Being | Year: 2013

This paper reviews the history of the transition from the belief that gastrointestinal ulcers are caused primarily by psychological factors to the current state of belief that they are caused primarily by infection and argues that neither is fully accurate. We argue that psychological factors play a significant role as predisposing to vulnerability, modulating of precipitation, and sustaining of gastric ulceration. We review data that challenge the assumption of a simple infectious disease model and adduce recent preclinical data that confirm the predisposing, modulatory, and sustaining roles for psychological factors. We note that others, too, are now challenging the adequacy of the contemporary simple bacterial infection model. We hope to replace the competition between psychology and medicine with cooperation in understanding and treating patients suffering gastric ulceration and ulcer. Applied Psychology: Health and Well-Being © 2012 The International Association of Applied Psychology.


Bostrom A.,University of Washington | Bohm G.,University of Bergen | O'Connor R.E.,National Science Foundation
Wiley Interdisciplinary Reviews: Climate Change | Year: 2013

Social marketing studies suggest that targeting segments of the population, by assessing and addressing their values and motives for actions in the design of communications, can improve the effectiveness of health and environmental communications efforts. Guidance for climate change communication now routinely proposes targeting specific audience segments as a fundamental principle, despite ambiguity regarding what specific behaviors to target and a lack of empirical evidence for specific strategies. Audience segmentation strategies proposed to date for climate change communications resemble those used in other social marketing efforts, but can be proprietary or opaque, with little data on the effects of implementing them. Insufficient evidence exists to systematically demonstrate the effectiveness of targeting or tailoring climate change communications per se, other than by reference to related research on health and environmental risk communications. Meta-analyses with systematic literature reviews, however, demonstrate that health risk communications can be more effective at changing attitudes and behaviors if they are tailored to the individual recipients' beliefs about their self-efficacy. The advent of technology-enabled microtargeting is rapidly expanding the opportunities for tailoring and targeting climate change communications and for adding to what we know from using them to make them effective. © 2013 John Wiley & Sons, Ltd.


Fomin F.V.,University of Bergen | Golovach P.,Durham University | Thilikos D.M.,National and Kapodistrian University of Athens
Journal of Combinatorial Theory. Series B | Year: 2011

We provide two parameterized graphs Γk, Πk with the following property: for every positive integer k, there is a constant ck such that every graph G with treewidth at least ck, contains one of Kk, Γk, Πk as a contraction, where Kk is a complete graph on k vertices. These three parameterized graphs can be seen as "obstruction patterns" for the treewidth with respect to the contraction partial ordering. We also present some refinements of this result along with their algorithmic consequences. © 2011 Elsevier Inc.


Tuastad L.,University of Bergen | O'Grady L.,University of Melbourne
Nordic Journal of Music Therapy | Year: 2013

The authors of this article have worked as music therapists in and outside prisons and have both completed qualitative studies that explore their work. Here, they present a narrative synthesis of their two studies while exploring the concept of music as a freedom practice in and outside prisons. Most of the prisoners and ex-prisoners participating in the two studies reported that music helped them to feel momentarily free from the harsh realities of both prison life and the world outside. The sense of freedom through music that was reported and analysed in the narrative synthesis is related to the dual nature of reality, through the categories of finding freedom by "escaping reality" and "entering reality." The categories describe how, through music, prisoners find a free space in an authoritative, suppressing and institutionalized environment, and also how music activities help the prisoner in building ties to the world outside prison while connecting to personal emotions and becoming humanized in a dehumanizing setting. In both cases, the participants from the two studies performed their freedom practice using music as a technology of the self. The paradox and potential of music as a freedom practice is illuminated and discussed using theories from community music therapy, musicology, sociology and criminology. In conclusion, the article proposes that music is one key to handling the complexities of the practice of freedom in everyday life. © 2013 Copyright The Grieg Academy Music Therapy Research Centre.


Ulvik R.J.,University of Bergen
Tidsskrift for den Norske lægeforening : tidsskrift for praktisk medicin, ny række | Year: 2013

A low supply of iron in the diet may result in iron deficiency and mild iron-deficiency anaemia in healthy individuals. Women are more susceptible than men because of menstrual iron loss. We compared the effect of a low dose of iron, administered as a dietary supplement, with a high pharmacological dose of iron to otherwise healthy individuals with iron deficiency and mild iron deficiency anaemia. In a randomised, double-blind trial conducted in 2000-2001, 73 women and three men with iron deficiency received either 27.6 mg of iron consisting of ferrous fumarate enriched with 13% haem iron, or 100 mg ferrosulphate daily for 12 weeks. Blood samples were analysed four times in the course of the treatment. The median ferritin value rose by 13 and 7 μg/l in the high-dose and low-dose group, respectively. The increase in ferritin was significantly higher in the high-dose than in the low dose group ( < 0.001). There was no statistically significant difference between the groups in the change in Hb, serum-iron or serum-iron binding capacity. The median haemoglobin value increased by 0.4 g/100 ml in both groups. Gastrointestinal side effects were experienced by 58% in the high-dose group and 35% in the low-dose group. Four subjects in the high-dose group and one in the low-dose group broke off the treatment because of side effects. A supplement of low-dose iron is enough to increase iron stores in cases of nutritional iron deficiency in healthy individuals and to optimise haemoglobin. High-dose iron caused the largest increase in iron stores. Low-dose iron resulted in the least side effects.


Ekrem T.,Norwegian University of Science and Technology | Willassen E.,University of Bergen | Stur E.,Norwegian University of Science and Technology
Molecular Phylogenetics and Evolution | Year: 2010

In this study we examine the utility of three mitochondrial (COI, COII, 16S) and two nuclear (CAD and EF-1a) markers for estimating lower-level phylogenetic relationships within the dipteran family Chironomidae. As a test case we use species of the genus Micropsectra and the putatively closely related genera Krenopsectra, Parapsectra and Paratanytarsus. We also examine the phylogenetic evidence for the currently accepted species groups within the genus Micropsectra. In our results, highly variable EF-1a sequences within some species indicate the first find of paralogous gene copies in nematocerous Diptera. Among the other genes, COI is found to have the weakest while CAD contains the strongest phylogenetic signal. The resulting phylogeny displays a well-supported, but paraphyletic Micropsectra with regard to Krenopsectra acuta and five Parapsectra species, indicating taxonomic synonymy of these genera with 100% posterior probability. The genus Parapsectra is polyphyletic within Micropsectra while Paratanytarsus remains monophyletic although with low posterior probability. Micropsectra acuta, M. bumasta, M. fallax, M. nohedensis, M. mendli, M. uliginosa, M. chionophila, M. nana, M. styriaca and M. wagneri will all be new combinations as a consequence of the synonymy. © 2010 Elsevier Inc.


Bhangu A.,Queen Elizabeth Hospital | Bhangu A.,University of Birmingham | Soreide K.,University of Stavanger | Soreide K.,University of Bergen | And 3 more authors.
The Lancet | Year: 2015

Acute appendicitis is one of the most common abdominal emergencies worldwide. The cause remains poorly understood, with few advances in the past few decades. To obtain a confident preoperative diagnosis is still a challenge, since the possibility of appendicitis must be entertained in any patient presenting with an acute abdomen. Although biomarkers and imaging are valuable adjuncts to history and examination, their limitations mean that clinical assessment is still the mainstay of diagnosis. A clinical classification is used to stratify management based on simple (non-perforated) and complex (gangrenous or perforated) inflammation, although many patients remain with an equivocal diagnosis, which is one of the most challenging dilemmas. An observed divide in disease course suggests that some cases of simple appendicitis might be self-limiting or respond to antibiotics alone, whereas another type often seems to perforate before the patient reaches hospital. Although the mortality rate is low, postoperative complications are common in complex disease. We discuss existing knowledge in pathogenesis, modern diagnosis, and evolving strategies in management that are leading to stratified care for patients. © 2015 Elsevier Ltd.


Hagen E.M.,University of Bergen
Acta neurologica Scandinavica. Supplementum | Year: 2011

A spinal cord injury (SCI) above the sixth thoracic vertebra interrupts the supraspinal control of the sympathetic nervous system causing an imbalance between the sympathetic and the parasympathetic nervous system. This article focuses on the symptoms, treatment and examination of autonomic disturbances of the cardiovascular and the urinary system after a SCI. A non-systematic literature search in the PubMed database. Frequent complications in the acute phase of cervical and high thoracic SCI are bradyarrhythmias, hypotension, hypothermia/hyperthermia, increased neurogenic shock, vagovagal reflex, supraventricular/ventricular ectopic beats, vasodilatation and congestion. Serious complications in the chronic phase of SCI are orthostatic hypotension, impaired cardiovascular reflexes, autonomic dysreflexia (AD), reduced sensation of cardiac pain, loss of reflex cardiac acceleration, quadriplegic cardiac atrophy due to loss of left ventricular mass and pseudo-myocardial infarction. AD is associated with a sudden, uncontrolled sympathetic response, triggered by stimuli below the injury. It may cause mild symptoms like skin rash or slight headache, but also severe hypertension, cerebral haemorrhage and death. Early recognition and prompt treatment are important. Urinary autonomic dysfunctions include hyperreflexia or areflexia of detrusor and/or sphincter of the bladder. Patients with SCI have a high risk of cardiovascular complications, AD and urinary autonomic dysfunction both in the acute phase and later, affecting their prognosis and quality of life. Knowledge of cardiovascular and urological complications after SCI is important for proper diagnosis and treatment. © 2011 John Wiley & Sons A/S.


This work reviews some of the major developments in the latent variable (LV) approach to exploratory and predictive modeling. Furthermore, it explores the nature and various aspects of the LV methodology and its role in science and technology. The immense potential of the LV approach to the analysis of complex systems is proven through its application in almost all branches of empirical science together with its proven usefulness to solve industrial problems. From its birth in psychology more than 100years ago, the approach has become the method of choice for analyzing multivariate data. © 2012 John Wiley & Sons, Ltd.


Gjerloev J.W.,Johns Hopkins University | Gjerloev J.W.,University of Bergen | Hoffman R.A.,NASA
Journal of Geophysical Research: Space Physics | Year: 2014

We present an empirical model of the equivalent current system in the ionosphere during the peak of a classical bulge-type auroral substorm. This model is derived from measurements made by ~110 ground magnetometer stations during 116 substorms. The data are temporally and spatially organized using global auroral images obtained by the Polar Visible Imaging System Earth Camera. The empirical equivalent current system displays three key features: a poleward shift of the westward electrojet connecting the postmidnight and premidnight components; a polar cap swirl; and significantly different magnitudes of the postmidnight and premidnight westward electrojets. This leads us to propose a two-wedge current system linking the ionosphere to the magnetosphere. The bulge current wedge is located in the premidnight region just equatorward of the open-closed field line boundary while another three-dimensional current system is located in the postmidnight region well within the auroral oval. We use Biot and Savart calculations and Tsyganenko mapping and show that this new model is a likely solution for the large-scale current system. ©2014. American Geophysical Union. All Rights Reserved.


Skoglund H.,University of Bergen | Einum S.,Norwegian University of Science and Technology | Einum S.,Norwegian Institute for Nature Research | Robertsen G.,Norwegian University of Science and Technology
Journal of Animal Ecology | Year: 2011

+Summary: 1.Timing of birth/hatching may have strong effects on offspring fitness. Breeding time is generally considered to have evolved to match offspring arrival with optimal seasonal environmental conditions, though this is rarely tested experimentally and factors shaping the relations between timing of birth and reproductive success are often poorly understood. 2.By manipulating incubation temperature of Atlantic salmon embryos, and hence controlling for maternal and genetic effects, we obtained offspring emerging from nests prior to (accelerated), during and after (decelerated) normal emergence times, and accordingly experienced widely different seasonal environmental conditions at emergence (stream temperature range 4-16°C). The accelerated group emerged at temperatures that are generally considered to be highly sub-optimal for growth and likely imposes strong constraints on feeding and activity, and during a peak in water discharge which is expected to negatively influence habitat availability. 3.In the wild, overall mortality during the period after emergence was 79%, and was significantly affected by both release density and emergence timing. Accelerated offspring, which emerged earliest and experienced the harshest environmental conditions, had both highest survival and largest final body size. The effect was particularly strong at the high density release site, where survival of accelerated offspring was significantly higher than both the normal and decelerated groups. 4.In more controlled semi-natural environments, all developmental groups were able to perform well, but accelerated offspring had a relatively better performance than the later emerging offspring when density was high. Furthermore, the relative performance of the different groups was not sensitive to water discharge regimes (temporally stable vs. fluctuating). 5.These results suggest that the performance of offspring in relation to seasonal timing of emergence is highly affected by competitive interactions in Atlantic salmon. Although a match between phenology and optimal seasonal environmental conditions may be highly important for organisms depending on specific resources that are only available during a limited period of the season, such resources may be available in variable amounts year around for many organisms. For these, offspring success may to a larger degree be shaped by the timing of their hatching/birth relative to each other, and particularly so under high population densities. © 2010 The Authors. Journal of Animal Ecology © 2010 British Ecological Society.


Bach J.R.,University of Bergen | Bach J.R.,University Hospital
Muscle and Nerve | Year: 2013

The purpose of this monograph is to describe noninvasive management of respiratory muscle weakness/paralysis for patients with neuromuscular disease (NMD) and spinal cord injury (SCI). Noninvasive ventilation (NIV) assists and supports inspiratory muscles, whereas mechanically assisted coughing (MAC) simulates an effective cough. Long-term outcomes will be reviewed as well as the use of NIV, MAC, and electrophrenic pacing (EPP) and diaphragm pacing (DP) to facilitate extubation and decannulation. Although EPP and DP can facilitate decannulation and maintain alveolar ventilation for high-level SCI patients when they cannot use NIV because of lack of access to oral interfaces, there is no evidence that they have any place in the management of NMD. © 2012 Wiley Periodicals, Inc.


Lauvsnes M.B.,University of Stavanger | Omdal R.,University of Stavanger | Omdal R.,University of Bergen
Journal of Neurology | Year: 2012

Neurological and psychiatric disorders are common in patients with systemic lupus erythematosus (SLE). While several pathogenetic mechanisms are thought to be involved, among of the most challenging and best investigated are antibodies against the N-methyl-D-aspartate (NMDA) receptor subtypes 2a and 2b (anti-NR2 antibodies). This review summarizes the most relevant mechanisms for neuropsychiatric (NP) involvement in SLE (NPSLE) with special emphasis on the role of anti-NR2 antibodies and provides an overview of published articles on anti-NR2 antibodies and brain involvement as of May 2011. In mice, neuronal cell death occurs when anti-NR2 antibodies gain access to the brain, either by injection directly into the brain, or by systemic immunization and abrogation of the blood-brain barrier. Either impaired memory and hippocampal atrophy, or emotional disturbances and atrophy of the amygdala follow, seemingly dependent on the method used for disruption of the blood- brain barrier. Recent studies indicate that the effect of anti- NR2 antibodies is dose dependent; at low concentrations they alter synaptic function; at higher concentrations they can cause neuronal cell death by apoptosis. An association between anti-NR2 antibodies and NPSLE has been confirmed in 6 out of 13 human studies; the manifestations are primarily of diffuse cerebral character. © Springer-Verlag 2011.


Schanche E.,University of Bergen
Psychotherapy | Year: 2013

Three interventions used to assist highly self-critical patients develop self-compassion are described and illustrated with case material. Theoretical background, assumed mechanism of change, and research evidence for each intervention is presented. © 2013 American Psychological Association.


Wilhelmsen-Langeland A.,University of Bergen
Behavioral sleep medicine | Year: 2014

Delayed sleep phase disorder (DSPD) is a circadian rhythm sleep disorder characterized by a substantial delay in the major sleep period, resulting in difficulties falling asleep and awakening at a socially desirable time in the morning. This study is the first to investigate the NEO-Personality Inventory-Revised profile of young adults with DSPD. The study includes 40 patients diagnosed with DSPD (mean age = 20.7) and 21 healthy controls (mean age = 21.1). Results showed that young adults with DSPD scored higher on Neuroticism, lower on Extroversion, and much lower on Conscientiousness than the control group. Assessing the personality profile of young adults with DSPD before initiating treatment might provide useful clinical guidance regarding the individual needs for follow up during treatment.


Rizza A.,University of Rome La Sapienza | Price M.C.,University of Bergen
Cognitive Processing | Year: 2012

Sequence-space synaesthesia is a type of visuo-spatial imagery in which numbers or calendar units are experienced to occupy locations in space. Previous studies have claimed that these synaesthetes (1) have stronger self-reported visual (but not spatial) imagery and (2) perform unusually well on mental rotation tasks that are usually taken to reflect spatial (but not visual) imagery. To further investigate whether this form of synaesthesia is related to spatial imagery, we compared synaesthetes to controls on the Object Spatial Imagery Questionnaire, a paper folding test and a mental rotation task. The synaesthetes did not differ from controls in self-reported spatial imagery, but showed a strong trend to report better visual imagery, replicating previously reported data patterns. Consistent with this, their paper folding and mental rotation performance was no better than controls. We also confirmed that, in our pooled sample, performance on both these tasks was positively correlated with self-reported spatial imagery. We suggest our data are more consistent with the view that sequence-space synaesthesia is related to visual than to spatial imagery, and we suggest reasons why previous studies may have found superior mental rotation performance. © 2012 Marta Olivetti Belardinelli and Springer-Verlag.


Dietrich H.M.,University of Tubingen | Tornroos K.W.,University of Bergen | Anwander R.,University of Tubingen
Angewandte Chemie - International Edition | Year: 2011

They do exist after all: Molecular [La(AlEt 4) 3] of high purity can be obtained from the reaction of [La(NMe 2) 3(LiCl) 3] with excess triethylaluminum. Although kinetically labile-the title complex decomposes gradually through β-H abstraction and release of ethane-alkane elimination reactions are feasible, as shown for the synthesis of metallocene complex [(C 5Me 5) 2La(AlEt 4)]. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Bremer S.,University of Bergen
International Journal of Sustainable Development | Year: 2013

An increasing tendency to classify environmental issues as 'wicked' has seen a wavering confidence in models of 'resource management' in favour of models of 'environmental governance'. This has come with an attendant shift in epistemological perspectives for the mobilisation of knowledge in support of society's collective deliberation and decision-making, with governance fields increasingly espousing a 'dialogic' approach. Looking through an 'interactive governance' lens, this article reveals a diversity of different forms of dialogue for the mobilisation of knowledge, before focusing on those forms that: a) are inclusive of all knowledge systems; b) bring together knowledge through reciprocal dialogue; c) allow for the negotiation of knowledge quality in terms of 'credibility, salience and legitimacy'. To this end, it unpacks and compares three specific approaches for the dialogic mobilisation of knowledge; deliberative democracy, collaborative learning and post-normal science. Copyright © 2013 Inderscience Enterprises Ltd.


Simmons D.K.,University of Hawaii at Manoa | Pang K.,University of Bergen | Martindale M.Q.,University of Hawaii at Manoa
EvoDevo | Year: 2012

Background: Nervous systems are thought to be important to the evolutionary success and diversification of metazoans, yet little is known about the origin of simple nervous systems at the base of the animal tree. Recent data suggest that ctenophores, a group of macroscopic pelagic marine invertebrates, are the most ancient group of animals that possess a definitive nervous system consisting of a distributed nerve net and an apical statocyst. This study reports on details of the evolution of the neural cell type specifying transcription factor family of LIM homeobox containing genes (Lhx), which have highly conserved functions in neural specification in bilaterian animals.Results: Using next generation sequencing, the first draft of the genome of the ctenophore Mnemiopsis leidyi has been generated. The Lhx genes in all animals are represented by seven subfamilies (Lhx1/5, Lhx3/4, Lmx, Islet, Lhx2/9, Lhx6/8, and LMO) of which four were found to be represented in the ctenophore lineage (Lhx1/5, Lhx3/4, Lmx, and Islet). Interestingly, the ctenophore Lhx gene complement is more similar to the sponge complement (sponges do not possess neurons) than to either the cnidarian-bilaterian or placozoan Lhx complements. Using whole mount in situ hybridization, the Lhx gene expression patterns were examined and found to be expressed around the blastopore and in cells that give rise to the apical organ and putative neural sensory cells.Conclusion: This research gives us a first look at neural cell type specification in the ctenophore M. leidyi. Within M. leidyi, Lhx genes are expressed in overlapping domains within proposed neural cellular and sensory cell territories. These data suggest that Lhx genes likely played a conserved role in the patterning of sensory cells in the ancestor of sponges and ctenophores, and may provide a link to the expression of Lhx orthologs in sponge larval photoreceptive cells. Lhx genes were later co-opted into patterning more diversified complements of neural and non-neural cell types in later evolving animals. © 2012 Simmons et al; licensee BioMed Central Ltd.


Helseth L.E.,University of Bergen
Measurement Science and Technology | Year: 2013

Under some circumstances, it is necessary to do optical spectroscopy on a front surface while at the same time monitoring the presence of a hidden metallic layer. Here, a novel sensor system to do this based on the combination of a visible light optical fibre spectrometer with a magnetic resonance eddy current sensor is demonstrated. It is shown that the the eddy current sensor can probe a hidden metallic film placed up to 1 cm behind the dielectric front surface. The combination of two such detection principles allows one to probe layered materials at multiple depths, revealing their electromagnetic properties at different frequencies. © 2013 IOP Publishing Ltd.


Ottersen T.,University of Bergen
Journal of Medical Ethics | Year: 2013

Two principles form the basis for much priority setting in health. According to the greater benefit principle, resources should be directed toward the intervention with the greater health benefit. According to the worse off principle, resources should be directed toward the intervention benefiting those initially worse off. Jointly, these principles accord with so-called prioritarianism. Crucial for its operationalisation is the specification of the worse off. In this paper, we examine how the worse off can be defined as those with the fewer lifetime Quality-Adjusted Life Years (QALYs). We contrast this proposal with several alternative specifications.


Kolding J.,University of Bergen | van Zwieten P.A.M.,Wageningen University
Fisheries Research | Year: 2012

Lakes and reservoirs are traditionally characterised from static morphological or chemical parameters such as depth and dissolved solids, while the dynamic impact of shifting water supplies has received little attention. There is increasing evidence, however, that the hydrodynamic regime in tropical water bodies plays a significant role in the injection and re-suspension of nutrients, and consequently has a strong influence on the biological communities and productivity. Lake level fluctuations can therefore be used as a proxy for bottom up driven processes. The application of a relative fluctuation index (RLLF) and its relationship with fish yields in a range of tropical lakes and reservoirs in Asia and Africa is reviewed. The RLLF is a simple empirical indicator defined as the mean amplitude of the annual or seasonal lake level fluctuations divided by the mean depth of the lake or reservoir, times 100. It builds on the classic morpho-edaphic index (MEI) for lakes and the more recent dynamic flood pulse concept (FPC), originally developed for rivers and floodplains. The RLLF index can be used as a predictive indicator for classifying lakes and reservoirs from stable to pulsed systems, and thereby their potential resilience to external disturbances. The index also has a strong log-linear relationship with the fish productivity. Shallow lakes and man-made reservoirs in general have the highest lake level changes, but also the highest fish yield per unit area, and even extreme fluctuations (amplitude higher than mean depth) seem only to accelerate the biological processes. The influence of water level changes on aquatic productivity should be taken into account when assessing environmental impacts within and outside man-made reservoirs. © 2011 Elsevier B.V.


Wiig H.,University of Bergen
Journal of Physiology | Year: 2011

The potential role of extravascular factors for the local as well as systemic response to an inflammatory stimulus is addressed here in light of recent data from the trachea, serving as a surrogate for lower airways, and spleen, because of its role in the immune response and fluid volume regulation. From analysis of interstitial fluid from trachea it is apparent that the colloid osmotic pressure is high relative to plasma, suggesting a significant buffering capacity against oedema formation, and also that there is a significant local production of proinflammatory mediators to a systemic inflammatory stimulus. Inflammatory stimuli may furthermore result in a rapid reduction in interstitial fluid pressure, thus leading to increased filtration and oedema formation. Knowledge regarding the fluid phase within the spleen microenvironment can be gathered via analysis of drained lymph. During a septic response induced by lipopolysaccharide injection, the spleen contributes significantly to the production of pro- and anti-inflammatory cytokines, and may induce protracted inflammation because of a dominant role in IL-6 production. Significant amounts of immune cells exit via lymph, and acquire specific activation signatures having been exposed to the spleen microenvironment. Although often overlooked, extravascular or interstitial factors may therefore contribute significantly to the inflammatory process and thus the ensuing oedema associated with inflammation. © 2011 The Author. Journal compilation © 2011 The Physiological Society.


Bremer S.,University of Bergen | Glavovic B.,Massey University
Coastal Management | Year: 2013

Integrated coastal management (ICM) has long sought to create political settings within which coastal communities can arrive at collective decisions, and support these decisions with the best quality knowledge available. Traditionally this has been through the integration of natural and social science with the political processes of decision-making and management, across the so-called science-policy interface. Contemporary developments in the field have seen the rising prominence of governance models, with a number of scholars arguing this to have implications for the shape of the science-policy interface. This article reviews the evolution in the theory and practice of the science-policy interface for ICM, before arguing that in the future the interface should be framed as a "governance setting." To this extent, the article distills four important guiding principles, including an interface that: (i) espouses an epistemology based in the dialogic mobilization of knowledge; (ii) includes all diverse knowledge perspectives; (iii) integrates disparate knowledge systems through dialogic reciprocity and co-existence; and (iv) has explicit regard for the negotiated quality of knowledge relative to a specific issue. © 2013 Copyright Taylor and Francis Group, LLC.


Stamnes J.J.,University of Bergen | Dhayalan V.,Bergen University College
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2012

For a linearly polarized three-dimensional Gaussian beam in air that is normally incident upon a plane interface with a uniaxial crystal with optic axis in an arbitrary direction, we present integral representations for the transmitted field suitable for asymptotic analysis and efficient numerical evaluation and derive analytical expressions for transmitted nontruncated Gaussian beams for the cases in which the incident beam is polarized parallel to the plane containing the optic axis and the interface normal and transverse to it. The general solution for an arbitrary polarization state of an incident Gaussian beam follows by superposition of these two solutions. © 2012 Optical Society of America.


Aksnes D.L.,University of Bergen | Cao F.J.,Complutense University of Madrid
Marine Ecology Progress Series | Year: 2011

Nearly 50 yr ago, the Michaelis-Menten (MM) model, originally derived for enzyme kinetics, was adapted to characterize microbial nutrient uptake and has become a framework for defining microbial traits in competition theory, evolutionary dynamics, and ocean ecosystem models. We provide theoretical evidence that microbial traits and environmental properties are not appropriately distinguished in current ecological modeling that makes use of MM models, and we propose a framework where inherent microbial traits are explicitly distinguished from environmental variables. This provides novel expectations on how nutrient uptake is affected by cell size, porter density, temperature, and nutrient regimes, and we show that uptake kinetics and tradeoffs likely differ between oligotrophic and eutrophic regimes. We present mechanistic expressions for the affinity and the half-saturation (K) coefficients, and our results suggest that K might behave opposite to that commonly assumed in ecological modeling and should be abandoned as an index of uptake efficiency. Our results further suggest that the effect of organism size, considered a master trait in modeling, on specific uptake and growth rates is effectively modified by porter density, although differently in oligotrophic and eutrophic regimes. While nutrient uptake studies have commonly been carried out at a bulk scale, which is much larger than that experienced by the organisms, our study emphasize the need for observations at the scale of the individual. © 2011 Inter-Research.


Price M.C.,University of Bergen | Mattingley J.B.,University of Queensland
Cortex | Year: 2013

For many people, thinking about certain types of common sequence - for example calendar units or numerals - elicits a vivid experience that the sequence members occupy spatial locations which are in turn part of a larger spatial pattern of sequence members. Recent research on these visuospatial experiences has usually considered them to be a variety of synaesthesia, and many studies have argued that this sequence-space synaesthesia is an automatic process, consistent with a traditional view that automaticity is a key property of synaesthesia. In this review we present a critical discussion of data from the three main paradigms that have been used to argue for automaticity in sequence-space synaesthesia, namely SNARC-like effects (Spatial-Numerical-Association-of-Response-Codes), spatial cueing, and perceptual incongruity effects. We suggest that previous studies have been too imprecise in specifying which type of automaticity is implicated. Moreover, mirroring previous challenges to automaticity in other types of synaesthesia, we conclude that existing data are at best ambiguous regarding the automaticity of sequence-space synaesthesia, and may even be more consistent with the effects of controlled (i.e., non-automatic) processes. This lack of strong evidence for automaticity reduces the temptation to seek explanations of sequence-space synaesthesia in terms of processes mediated by qualitatively abnormal brain organization or mechanisms. Instead, more parsimonious explanations in terms of extensively rehearsed associations, established for example via normal processes of visuospatial imagery, are convergent with arguments that synaesthetic phenomena are on a continuum with normal cognition. © 2012 Elsevier Ltd.


Schuler H.,Karolinska Institutet | Ziegler M.,University of Bergen
FEBS Journal | Year: 2013

ADP-ribosyltransferase ARTD1/PARP1 is a target for cancer and ischemia drug development. Several other ARTD-family enzymes have been characterized in recent years, and it has become clear that their inhibition might also have therapeutic value. This minireview series summarizes current knowledge of pharmacological inhibition of ADP-ribosyltransferases by a compound class called PARP inhibitors and the prospects for drug development. © 2013 FEBS.


Hirnstein M.,University of Bergen | Coloma Andrews L.,Ludwig Maximilians University of Munich | Hausmann M.,Durham University
Archives of Sexual Behavior | Year: 2014

Sex differences in specific cognitive abilities are well documented, but the biological, psychological, and sociocultural interactions that may underlie these differences are largely unknown. We examined within a biopsychosocial approach how gender stereotypes affect cognitive sex differences when adult participants were tested in mixed- or same-sex groups. A total of 136 participants (70 women) were allocated to either mixed- or same-sex groups and completed a battery of sex-sensitive cognitive tests (i.e., mental rotation, verbal fluency, perceptual speed) after gender stereotypes or gender-neutral stereotypes (control) were activated. To study the potential role of testosterone as a mediator for group sex composition and stereotype boost/threat effects, saliva samples were taken before the stereotype manipulation and after cognitive testing. The results showed the typical male and female advantages in mental rotation and verbal fluency, respectively. In general, men and women who were tested in mixed-sex groups and whose gender stereotypes had not been activated performed best. Moreover, a stereotype threat effect emerged in verbal fluency with reduced performance in gender stereotyped men but not women. Testosterone levels did not mediate the effects of group sex composition and stereotype threat nor did we find any relationship between testosterone and cognitive performance in men and women. Taken together, the findings suggest that an interaction of gender stereotyping and group sex composition affects the performance of men and women in sex-sensitive cognitive tasks. Mixed-sex settings can, in fact, increase cognitive performance as long as gender-stereotyping is prevented. © 2014, The Author(s).


Fachner J.,University of Jyvaskyla | Gold C.,University of Bergen | Erkkila J.,University of Jyvaskyla
Brain Topography | Year: 2013

Fronto-temporal areas process shared elements of speech and music. Improvisational psychodynamic music therapy (MT) utilizes verbal and musical reflection on emotions and images arising from clinical improvisation. Music listening is shifting frontal alpha asymmetries (FAA) in depression, and increases frontal midline theta (FMT). In a two-armed randomized controlled trial (RCT) with 79 depressed clients (with comorbid anxiety), we compared standard care (SC) versus MT added to SC at intake and after 3 months. We found that MT significantly reduced depression and anxiety symptoms. The purpose of this study is to test whether or not MT has an impact on anterior fronto-temporal resting state alpha and theta oscillations. Correlations between anterior EEG, Montgomery-Åsberg Depression Rating Scale (MADRS) and the Hospital Anxiety and Depression Scale - Anxiety Subscale (HADS-A), power spectral analysis (topography, means, asymmetry) and normative EEG database comparisons were explored. After 3 month of MT, lasting changes in resting EEG were observed, i.e., significant absolute power increases at left fronto-temporal alpha, but most distinct for theta (also at left fronto-central and right temporoparietal leads). MT differed to SC at F7-F8 (z scored FAA, p <.03) and T3-T4 (theta, p <.005) asymmetry scores, pointing towards decreased relative left-sided brain activity after MT; pre/post increased FMT and decreased HADS-A scores (r =.42, p <.05) indicate reduced anxiety after MT. Verbal reflection and improvising on emotions in MT may induce neural reorganization in fronto-temporal areas. Alpha and theta changes in fronto-temporal and temporoparietal areas indicate MT action and treatment effects on cortical activity in depression, suggesting an impact of MT on anxiety reduction. © 2012 Springer Science+Business Media, LLC.


Skeie B.S.,University of Bergen
BioMed research international | Year: 2013

Gamma knife surgery (GKS) may be used for recurring glioblastomas (GBMs). However, patients have then usually undergone multimodal treatment, which makes it difficult to specifically validate GKS independent of established treatments. Thus, we developed an experimental brain tumor model to assess the efficacy and radiotoxicity associated with GKS. GBM xenografts were implanted intracerebrally in nude rats, and engraftment was confirmed with MRI. The rats were allocated to GKS, with margin doses of 12 Gy or 18 Gy, or to no treatment. Survival time was recorded, tumor sections were examined, and radiotoxicity was evaluated in a behavioral open field test. In the first series, survival from the time of implantation was 96 days in treated rats and 72 days in controls (P < 0.001). In a second experiment, survival was 72 days in the treatment group versus 54 days in controls (P < 0.006). Polynuclear macrophages and fibrosis was seen in groups subjected to GKS. Untreated rats with GBM xenografts displayed less mobility than GKS-treated animals in the open field test 4 weeks after treatment (P = 0.04). GKS administered with clinically relevant doses prolongs survival in rats harboring GBM xenografts, and the associated toxicity is mild.


Hyltoft Petersen P.,University of Bergen | Klee G.G.,Mayo Medical School
Clinica Chimica Acta | Year: 2014

Background: Diagnostic decisions based on decision limits according to medical guidelines are different from the majority of clinical decisions due to the strict dichotomization of patients into diseased and non-diseased. Consequently, the influence of analytical performance is more critical than for other diagnostic decisions where much other information is included. The aim of this opinion paper is to investigate consequences of analytical quality and other circumstances for the outcome of "Guideline-Driven Medical Decision Limits". Terms: Effects of analytical bias and imprecision should be investigated separately and analytical quality specifications should be estimated accordingly. Biological variation and analytical performance: Use of sharp decision limits doesn't consider biological variation and effects of this variation are closely connected with the effects of analytical performance. Such relationships are investigated for the guidelines for HbA1c in diagnosis of diabetes and in risk of coronary heart disease based on serum cholesterol. The effects of a second sampling in diagnosis give dramatic reduction in the effects of analytical quality showing minimal influence of imprecision up to 3 to 5% for two independent samplings, whereas the reduction in bias is more moderate and a 2% increase in concentration doubles the percentage of false positive diagnoses, both for HbA1c and cholesterol. Frequency of follow-up laboratory tests: An alternative approach comes from the current application of guidelines for follow-up laboratory tests according to clinical procedure orders, e.g. frequency of parathyroid hormone requests as a function of serum calcium concentrations. Here, the specifications for bias can be evaluated from the functional increase in requests for increasing serum calcium concentrations. Probability function for diagnoses: In consequence of the difficulties with biological variation and the practical utilization of concentration dependence of frequency of follow-up laboratory tests already in use, a kind of probability function for diagnosis as function of the key-analyte is proposed. © 2013 Elsevier B.V.


Fitch A.C.,University of Bergen | Fitch A.C.,U.S. National Center for Atmospheric Research | Olson J.B.,National Oceanic and Atmospheric Administration | Lundquist J.K.,University of Colorado at Boulder | Lundquist J.K.,National Renewable Energy Laboratory
Journal of Climate | Year: 2013

For assessing the impacts of wind farms on regional climate, wind farms may be represented in climate models by an increase in aerodynamic roughness length. Studies employing this method have found nearsurface temperature changes of 1-2K over wind farm areas. By contrast, mesoscale and large-eddy simulations (LES), which represent wind farms as elevated sinks of momentum, generally showed temperature changes of less than 0.5 K. This study directly compares the two methods of representing wind farms in simulations of a strong diurnal cycle. Nearly the opposite wake structure is seen between the two methods, both during the day and at night. The sensible heat fluxes are generally exaggerated in the enhanced roughness approach, leading to much greater changes in temperature. Frequently, the two methods display the opposite sign in temperature change. Coarse resolution moderates the sensible heat fluxes but does not significantly improve the near-surface temperatures or low-level wind speed deficit. Since wind farm impacts modeled by the elevated momentum sink approach are similar to those seen in observations and from LES, the authors conclude that the increased surface roughness approach is not an appropriate option to represent wind farms or explore their impacts. © 2013 American Meteorological Society.


Forre M.,University of Bergen
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

Without a formal derivation, we propose a formula for the total and single-differential cross sections in the problem of one-photon double ionization of an atom. The formula is benchmarked against accurate experimental data for the total cross section of helium. Furthermore, a direct comparison with ab initio calculations for the double ionization of Li + suggests that the framework is valid for the entire helium isoelectronic sequence. To this end, we introduce a formula for the double ionization of lithium as well as for the triple ionization of lithium and beryllium. © 2012 American Physical Society.


Johnsen B.H.,University of Bergen
International maritime health | Year: 2012

The current research investigated cultural differences in emotional intelligence among top officers on board vessels of multicultural maritime companies. We found that Southeast Asian officers scored higher than European officers on the total Emotional Intelligence scale. When separating the EQ scale in its facets, higher scores for Asian officers were found on "Utilization of emotions", "Handling relationships", and on "Self-control". Another finding was that Chief officers/Second engineers scored higher than Masters/Chief Officers on "Self-control". Finally, we found a negative correlation between age and scores on the facet of "Self-control". These crosscultural differences may have implications for interpersonal relations and ship management.


Olweus D.,University of Bergen
Criminal Behaviour and Mental Health | Year: 2011

Aim To examine whether being a bully at school predicts later criminality. Method Longitudinal, prospective associations are reported between bullying and later criminality over the 8-year period from age 16 to 24. Results Bullying in early adolescence strongly predicted later criminality. The former school bullies were heavily overrepresented in the crime registers. Some 55% of them had been convicted of one or more crimes and as much as 36% had been convicted of at least three crimes in the studied period. Effect sizes in the form of Odds Ratios were substantial for both general crimes and violent crimes, varying between 3.47 and 7.79. Copyright © 2011 John Wiley & Sons, Ltd.


Andreev V.V.,Gomel State University | Osland P.,University of Bergen | Pankov A.A.,Salam University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

We discuss the expected sensitivity to Z′ boson effects in the W± boson pair production process at the Large Hadron Collider (LHC). The results of a model-dependent analysis of Z′ boson effects are presented as constraints on the Z-Z′ mixing angle φ and Z′ boson mass. The process pp→W+W-+X allows us to place stringent constraints on the Z-Z′ mixing angle. Specifically, we find that the present LHC bounds on the mixing angle are of the order a few times 10-3, which is of the same order as those derived from the electroweak data. These results were derived from analysis of W-pair production at s=8TeV and integrated luminosity of 20fb-1. Further improvement on the constraining of this mixing can be achieved from the analysis of data on WW→lνl′ν′ (l,l′=e or μ) and WW→lνjj final states collected at the LHC with nominal energy and luminosity, 14 TeV and 100fb-1, and should be φ∼10-4-10-3. © 2014 American Physical Society.


The immatures and males of A. (Karelia) illinoensis (Malloch), A. (K.) philosphagnos Beck et Beck, A. (K.) pulchripennis (Lundbeck), A. (A.) mallochi (Walley), A. (A.) aspera Roback, A. (A.) basalis (Walley) and A. (Asayia) annulata (Say) are redescribed and/or illustrated. A. (A.) basalis (Walley) is regarded as a valid species separate from Nearctic A. (A.) monilis auct nec (L.). Seven species of Ablabesmyia were found from Lake Winnipeg, Manitoba, 3 from Marion Lake, British Columbia while other samples from Alberta to Ontario contained no more than one species. Keys are given to Nearctic immatures of Ablabesmyia. The distribution of Ablabesmyia in Lake Winnipeg is mapped and discussed. The separation of larval instars is shown approximately to follow Dyar's rule. Copyright © 2011 · Magnolia Press.