913 research outputs found
Reproductive patterns in king eiders
Thesis (Ph.D.) University of Alaska Fairbanks, 2009Mammalian predation, avian predation, female body condition and food availability on the breeding ground are likely the main factors influencing nesting success in tundra-nesting waterfowl. These driving factors are mediated by the primary life history characteristics; incubation behavior, female body size, nesting associations, and nest site selection. I created a conceptual model illustrating how these factors are interrelated and how they impact nest success through a variety of pathways to better understand the evolution of a species' nesting strategy and patterns observed in the field. The importance of the driving factors likely varies between sites and with the species nesting strategy. Given the conceptual model, I predicted the difference in life history characteristics and nesting success at two sites that vary in any of the four driving factors. I tested the model and associated predictions using King Eider females (Somateria spectabilis) breeding on Alaska's coastal plain by comparing selective forces influencing nesting strategies at two sites, Teshekpuk and Kuparuk, between 2002 and 2006. King Eiders fit the model with some modifications to the mediating pathways. Site differences were found in many of the reproductive parameters which matched the prediction of more available forage at Kuparuk than at Teshekpuk. No differences in either avian or mammalian predation pressure were evident between sites. Eiders at Kuparuk had higher nest survival and incubation constancy than at Teshekpuk. Body mass and nest selection were similar between sites. Although questions concerning the nesting strategies of King Eider remain, I feel that this was a valid approach to identifying selective forces impacting nesting strategies and applicable to tundra nesting waterfowl in general.1. Introduction -- 2. Incubation behavior of King Eiders on the coastal plain of Northern Alaska -- 3. Characterizing the nutritional strategy of incubating king eiders Somateria spectabilis in Northern Alaska -- 4. Factors influencing nesting success of king eiders on Northern Alaska's coastal plain -- 5. Effects of concealment, seclusion, and nesting associations on nest site selection by King Eiders -- 6. Estimating nest site fidelity in king eiders using microsatellite genotyping; what worked, what didn't and why -- 7. Conclusions
Behavioural Phenotypes and the Structure of Human Cognition
Human cognitive uniqueness is often defined in terms of cognitive abilities such as introspection, imitation and cooperativeness. However, little is known about how those traits vary in populations or correlate across individuals. Here we test whether those three cognitive domains are correlated manifestations of an underlying factor, analogous to the psychometric ‘g’ factor, or independent ‘behavioural phenotypes’, analogous to the ‘Big-Five’ personality components. We selected eight variables measuring introspection and extraversion, verbal and physical imitation, cooperation and punishment, and evaluated their individual variability, domain-consistency and sub-structuring in a sample of 84 individuals. Results show high variation and limited clustering into three independent ‘behavioural phenotypes’ of introspection, imitation and cooperation. Only one significant correlation was identified (between two measures of extraversion), while other within-domain measures (introspection vs. extraversion, verbal vs. physical imitation, and cooperation vs. punishment) were not associated. Finally, no between-domain association was identified either through correlations or factor analysis. Overall, the results do not lend support to the hypothesis of a general ‘behavioural phenotype’ underlying individual behaviour. The independence of behaviours of introspection, imitation and cooperation may be the reason why individuals are able to adopt different behavioural strategies (combinations of behavioural phenotypes) and play distinct roles in the maintenance of human distinctive features such as hyper-cooperation and cumulative culture
Alcohol intoxication and mental health among adolescents--a population review of 8983 young people, 13-19 years in North-Trondelag, Norway: the Young-HUNT Study
BACKGROUND: The aims of this study were to describe alcohol use among Norwegian teenagers and investigate the associations between mental health problems and alcohol intoxications with focus on age and gender.
METHODS: Population based, cross-sectional survey addressing all adolescents aged 13-19 years, attending secondary or high school in North - Trondelag County, Norway. 8983 youths (91%) answered the Young-HUNT questionnaire in the 1995-1997 survey. Logistic regression models were used to study associations.RESULTS: 80% of the respondents reported that they had tried drinking alcohol, and 57% had been intoxicated at least once. The proportion of the
students, which had tried alcohol, was equal in both genders and increased with age. Attention problems and conduct problems were strongly associated with frequent alcohol intoxications in both genders. Anxiety and depressive symptoms among girls were also related to high numbers of intoxications
CONCLUSION: Gender differences in number of alcohol intoxications were small. There was a close association between both conduct and attention problems and high alcohol consumption in both genders. Girls with symptoms of anxiety and depression reported more frequent alcohol intoxications
Genomics reveal population structure, evolutionary history, and signatures of selection in the northern bottlenose whale, Hyperoodon ampullatus
Funding: This work was supported by Fisheries and Oceans Canada (DFO) Maritimes and National Geographic emerging explorer grant to L.J.F, with support by and Natural Sciences and Engineering Research Council of Canada (NSERC) and Killam Nova Scotia Doctoral Scholarships. Work was also supported by US Office of Naval Research and US Strategic Environmental Research and Development Program (SERDP), DFO, University of Windsor, Crown-Indigenous Relations and Northern Affairs Canada, Nunavut Fisheries Association, Government of Nunavut, and NSERC. Funding and resources for sequencing the northern bottlenose whale genome was supported by the CanSeq150 program of Canada’s Genomics Enterprise.Information on wildlife population structure, demographic history, and adaptations are fundamental to understanding species evolution and informing conservation strategies. To study this ecological context for a cetacean of conservation concern, we conducted the first genomic assessment of the northern bottlenose whale, Hyperoodon ampullatus, using whole-genome resequencing data (n = 37) from five regions across the North Atlantic Ocean. We found a range-wide pattern of isolation-by-distance with a genetic subdivision distinguishing three subgroups: the Scotian Shelf, western North Atlantic, and Jan Mayen regions. Signals of elevated levels of inbreeding in the Endangered Scotian Shelf population indicate this population may be more vulnerable than the other two subgroups. In addition to signatures of inbreeding, evidence of local adaptation in the Scotian Shelf was detected across the genome. We found a long-term decline in effective population size for the species, which poses risks to their genetic diversity and may be exacerbated by the isolating effects of population subdivision. Protecting important habitat and migratory corridors should be prioritized to rebuild population sizes that were diminished by commercial whaling, strengthen gene flow, and ensure animals can move across regions in response to environmental changes.Publisher PDFPeer reviewe
Effects of geolocators on hatching success, return rates, breeding movements, and change in body mass in 16 species of Arctic-breeding shorebirds
Additional Authors: Bruce Casler; Maureen Christie; Jonathan T. Coleman; Jesse R. Conklin; Willow B. English; H. River Gates; Olivier Gilg; Marie-Andrée Giroux; Ken Gosbell; Chris Hassell; Jim Helmericks; Andrew Johnson; Borgný Katrínardóttir; Kari Koivula; Jean-Francois Lamarre; Johannes Lang; David B. Lank; Nicolas Lecomte; Joe Liebezeit; Vanessa Loverti; Laura McKinnon; Clive Minton; David Mizrahi; Erica Nol; Veli-Matti Pakanen; Johanna Perz; Ron Porter; Jennie Rausch; Jeroen Reneerkens; Nelli Rönkä; Sarah Saalfeld; Nathan Senner; Benoît Sittler; Paul A. Smith; Kristine Sowl; Audrey Taylor; David H. Ward; Stephen YezerinacCitation: Weiser, E.L., R.B. Lanctot, S.C. Brown, J.A. Alves, P.F. Battley, R. Bentzen, J. Bêty, M.A. Bishop, M. Boldenow, L. Bollache, B. Casler, M. Christie, J.T. Coleman, J.R. Conklin, W.B. English, H.R. Gates, O. Gilg, M.-A. Giroux, K. Gosbell, C. Hassell, J. Helmericks, A. Johnson, B. Katrínardóttir, K. Koivula, E. Kwon, J.-F. Lamarre, J. Lang, D.B. Lank, N. Lecomte, J. Liebezeit, V. Loverti, L. McKinnon, C. Minton, D. Mizrahi, E. Nol, V.-M. Pakanen, J. Perz, R. Porter, J. Rausch, J. Reneerkens, N. Rönkä, S. Saalfeld, N. Senner, B. Sittler, P.A. Smith, K. Sowl, A. Taylor, D.H. Ward, S. Yezerinac, and B.K. Sandercock. 2016. Effects of geolocators on hatching success, return rates, breeding movements and change in body mass in 16 species of Arctic-breeding shorebirds. Movement Ecology 4: art12.
URL: http://movementecologyjournal.biomedcentral.com/articles/10.1186/s40462-016-0077-6Background: Geolocators are useful for tracking movements of long-distance migrants, but potential negative effects on birds have not been well studied. We tested for effects of geolocators (0.8–2.0 g total, representing 0.1–3.9 % of mean body mass) on 16 species of migratory shorebirds, including five species with 2–4 subspecies each for a total of 23 study taxa. Study species spanned a range of body sizes (26–1091 g) and eight genera, and were tagged at 23 breeding and eight nonbreeding sites. We compared breeding performance and return rates of birds with geolocators to control groups while controlling for potential confounding variables. Result: We detected negative effects of tags for three small-bodied species. Geolocators reduced annual return rates for two of 23 taxa: by 63 % for semipalmated sandpipers and by 43 % for the arcticola subspecies of dunlin. High resighting effort for geolocator birds could have masked additional negative effects. Geolocators were more likely to negatively affect return rates if the total mass of geolocators and color markers was 2.5–5.8 % of body mass than if tags were 0.3–2.3 % of body mass. Carrying a geolocator reduced nest success by 42 % for semipalmated sandpipers and tripled the probability of partial clutch failure in semipalmated and western sandpipers. Geolocators mounted perpendicular to the leg on a flag had stronger negative effects on nest success than geolocators mounted parallel to the leg on a band. However, parallel-band geolocators were more likely to reduce return rates and cause injuries to the leg. No effects of geolocators were found on breeding movements or changes in body mass. Among-site variation in geolocator effect size was high, suggesting that local factors were important. Conclusions: Negative effects of geolocators occurred only for three of the smallest species in our dataset, but were substantial when present. Future studies could mitigate impacts of tags by reducing protruding parts and minimizing use of additional markers. Investigators could maximize recovery of tags by strategically deploying geolocators on males, previously marked individuals, and successful breeders, though targeting subsets of a population could bias the resulting migratory movement data in some species
Incorporating NTCP into randomized trials of proton versus photon therapy
Purpose: We propose and simulate a model-based methodology to incorporate heterogeneous treatment benefit of proton therapy (PrT) versus photon therapy into randomized trial designs. We use radiation-induced pneumonitis (RP) as an exemplar. The aim is to obtain an unbiased estimate of how predicted difference in normal tissue complications probability (DNTCP) converts into clinical outcome on the patient level. Materials and Methods: DNTCP data from in silico treatment plans for photon therapy and PrT for patients with locally advanced lung cancer as well as randomly sampled clinical risk factors were included in simulations of trial outcomes. The model used at point of analysis of the trials was an iQUANTEC model. Trial outcomes were examined with Cox proportional hazards models, both in case of a correctly specified model and in a scenario where there is discrepancy between the dose metric used for DNTCP and the dose metric associated with the "true" clinical outcome, that is, when the model is misspecified. We investigated how outcomes from such a randomized trial may feed into a model-based estimate of the patient-level benefit from PrT, by creating patient-specific predicted benefit probability distributions. Results: Simulated trials showed benefit in accordance with that expected when the NTCP model was equal to the model for simulating outcome. When the model was misspecified, the benefit changed and we observed a reversal when the driver of outcome was high-dose dependent while the NTCP model was mean-dose dependent. By converting trial results into probability distributions, we demonstrated large heterogeneity in predicted benefit, and provided a randomized measure of the precision of individual benefit estimates. Conclusions: The design allows for quantifying the benefit of PrT referral, based on the combination of NTCP models, clinical risk factors, and traditional randomization. A misspecified model can be detected through a lower-than-expected hazard ratio per predicted DNTCP
Hypofractionated radiotherapy has the potential for second cancer reduction
<p>Abstract</p> <p>Background and Purpose</p> <p>A model for carcinoma and sarcoma induction was used to study the dependence of carcinogenesis after radiotherapy on fractionation.</p> <p>Materials and methods</p> <p>A cancer induction model for radiotherapy doses including fractionation was used to model carcinoma and sarcoma induction after a radiation treatment. For different fractionation schemes the dose response relationships were obtained. Tumor induction was studied as a function of dose per fraction.</p> <p>Results</p> <p>If it is assumed that the tumor is treated up to the same biologically equivalent dose it was found that large dose fractions could decrease second cancer induction. The risk decreases approximately linear with increasing fraction size and is more pronounced for sarcoma induction. Carcinoma induction decreases by around 10% per 1 Gy increase in fraction dose. Sarcoma risk is decreased by about 15% per 1 Gy increase in fractionation. It is also found that tissue which is irradiated using large dose fractions to dose levels lower than 10% of the target dose potentially develop less sarcomas when compared to tissues irradiated to all dose levels. This is not observed for carcinoma induction.</p> <p>Conclusions</p> <p>It was found that carcinoma as well as sarcoma risk decreases with increasing fractionation dose. The reduction of sarcoma risk is even more pronounced than carcinoma risk. Hypofractionation is potentially beneficial with regard to second cancer induction.</p
The challenges of the expanded availability of genomic information: an agenda-setting paper
Rapid advances in microarray and sequencing technologies are making genotyping and genome sequencing more affordable and readily available. There is an expectation that genomic sequencing technologies improve personalized diagnosis and personalized drug therapy. Concurrently, provision of direct-to-consumer genetic testing by commercial providers has enabled individuals’ direct access to their genomic data. The expanded availability of genomic data is perceived as influencing the relationship between the various parties involved including healthcare professionals, researchers, patients, individuals, families, industry, and government. This results in a need to revisit their roles and responsibilities. In a 1-day agenda-setting meeting organized by the COST Action IS1303 “Citizen’s Health through public-private Initiatives: Public health, Market and Ethical perspectives,” participants discussed the main challenges associated with the expanded availability of genomic information, with a specific focus on public-private partnerships, and provided an outline from which to discuss in detail the identified challenges. This paper summarizes the points raised at this meeting in five main parts and highlights the key cross-cutting themes. In light of the increasing availability of genomic information, it is expected that this paper will provide timely direction for future research and policy making in this area.Funding Deborah Mascalzoni is supported under Grant Agreement number 305444. Álvaro Mendes is supported by the FCT—The Portuguese Foundation for Science and Technology under postdoctoral grant SFRH/BPD/88647/2012. Isabelle Budin-Ljøsne receives support from the National Research and Innovation Platform for Personalized Cancer Medicine funded by The Research Council of Norway (NFR BIOTEK2021/ES495029) and Biobank Norway funded by The Research Council of Norway—grant number 245464. Heidi Carmen Howard is partly supported by supported by the Swedish Foundation for Humanities and Social Science under grant M13-0260:1), the Biobanking and Molecular Resource Infrastructure of Sweden (BBMRI.se) and the BBMRI-ERIC. Brígida Riso is supported by the Portuguese Foundation for Science and Technology (FCT) under the PhD grant SFRH/BD/100779/2014. Heidi Beate Bentzen receives support from the project Legal Regulation of Information Processing relating to Personalized Cancer Medicine funded by The Research Council of Norway BIOTEK2021/238999
STROGAR – STrengthening the Reporting Of Genetic Association studies in Radiogenomics
AbstractDespite publication of numerous radiogenomics studies to date, positive single nucleotide polymorphism (SNP) associations have rarely been reproduced in independent validation studies. A major reason for these inconsistencies is a high number of false positive findings because no adjustments were made for multiple comparisons. It is also possible that some validation studies were false negatives due to methodological shortcomings or a failure to reproduce relevant details of the original study. Transparent reporting is needed to ensure these flaws do not hamper progress in radiogenomics. In response to the need for improving the quality of research in the area, the Radiogenomics Consortium produced an 18-item checklist for reporting radiogenomics studies. It is recognised that not all studies will have recorded all of the information included in the checklist. However, authors should report on all checklist items and acknowledge any missing information. Use of STROGAR guidelines will advance the field of radiogenomics by increasing the transparency and completeness of reporting
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