Publications

polar bear encephalitis: establishment of a comprehensive next-generation pathogen analysis pipeline for captive and free-living wildlife.	this report describes three possibly related incidences of encephalitis, two of them lethal, in captive polar bears (ursus maritimus). standard diagnostic methods failed to identify pathogens in any of these cases. a comprehensive, three-stage diagnostic 'pipeline' employing both standard serological methods and new dna microarray and next generation sequencing-based diagnostics was developed, in part as a consequence of this initial failure. this pipeline approach illustrates the strengths, wea ...	2014	24534459
the fur of mammals in exposed environments; do crypsis and thermal needs necessarily conflict? the polar bear and marsupial koala compared.	the furs of mammals have varied and complex functions. other than for thermoregulation, fur is involved in physical protection, sensory input, waterproofing and colouration, the latter being important for crypsis or camouflage. some of these diverse functions potentially conflict. we have investigated how variation in cryptic colouration and thermal features may interact in the coats of mammals and influence potential heat inflows from solar radiation, much of which is outside the visible spectr ...	2014	24366474
study yields “genghis khan” of brown bears, new understanding of brown and polar bear evolution.		2014	24860012
grizzly bear hair reveals toxic exposure to mercury through salmon consumption.	mercury obtained from the diet accumulates in mammalian hair as it grows thus preserving a record of mercury intake over the growth period of a given hair segment. we adapted a microanalysis approach, using laser ablation inductively coupled plasma mass spectrometry, to characterize temporal changes in mercury exposure and uptake in wild and captive grizzly bears. captive grizzlies fed diets containing known and varied amounts of mercury provided data to allow prediction of hg ingestion rates in ...	2014	24904971
longer ice-free seasons increase the risk of nest depredation by polar bears for colonial breeding birds in the canadian arctic.	northern polar regions have warmed more than other parts of the globe potentially amplifying the effects of climate change on biological communities. ice-free seasons are becoming longer in many areas, which has reduced the time available to polar bears (ursus maritimus) to hunt for seals and hampered bears' ability to meet their energetic demands. in this study, we examined polar bears' use of an ancillary prey resource, eggs of colonial nesting birds, in relation to diminishing sea ice coverag ...	2014	24500172
population genomics reveal recent speciation and rapid evolutionary adaptation in polar bears.	polar bears are uniquely adapted to life in the high arctic and have undergone drastic physiological changes in response to arctic climates and a hyper-lipid diet of primarily marine mammal prey. we analyzed 89 complete genomes of polar bear and brown bear using population genomic modeling and show that the species diverged only 479-343 thousand years bp. we find that genes on the polar bear lineage have been under stronger positive selection than in brown bears; nine of the top 16 genes under s ...	2014	24813606
brown and polar bear y chromosomes reveal extensive male-biased gene flow within brother lineages.	brown and polar bears have become prominent examples in phylogeography, but previous phylogeographic studies relied largely on maternally inherited mitochondrial dna (mtdna) or were geographically restricted. the male-specific y chromosome, a natural counterpart to mtdna, has remained underexplored. although this paternally inherited chromosome is indispensable for comprehensive analyses of phylogeographic patterns, technical difficulties and low variability have hampered its application in most ...	2014	24667925
polar bears exhibit genome-wide signatures of bioenergetic adaptation to life in the arctic environment.	polar bears (ursus maritimus) face extremely cold temperatures and periods of fasting, which might result in more severe energetic challenges than those experienced by their sister species, the brown bear (u. arctos). we have examined the mitochondrial and nuclear genomes of polar and brown bears to investigate whether polar bears demonstrate lineage-specific signals of molecular adaptation in genes associated with cellular respiration/energy production. we observed increased evolutionary rates ...	2014	24504087
full genome sequences of zebra-borne equine herpesvirus type 1 isolated from zebra, onager and thomson's gazelle.	a strain of equine herpesvirus type 1 (ehv-1) was isolated from zebra. this strain, called "zebra-borne ehv-1", was also isolated from an onager and a gazelle in zoological gardens in u.s.a. the full genome sequences of the 3 strains were determined. they shared 99% identities with each other, while they shared 98% and 95% identities with the horse derived ehv-1 and equine herpesvirus type 9, respectively. sequence data indicated that the ehv-1 isolated from a polar bear in germany is one of the ...	2014	24920546
molecular phylogeny and snp variation of polar bears (ursus maritimus), brown bears (u. arctos), and black bears (u. americanus) derived from genome sequences.	we assessed the relationships of polar bears (ursus maritimus), brown bears (u. arctos), and black bears (u. americanus) with high throughput genomic sequencing data with an average coverage of 25× for each species. a total of 1.4 billion 100-bp paired-end reads were assembled using the polar bear and annotated giant panda (ailuropoda melanoleuca) genome sequences as references. we identified 13.8 million single nucleotide polymorphisms (snp) in the 3 species aligned to the polar bear genome. th ...	2014	24477675
immobilization of polar bears (ursus maritimus phipps) with a mixture of tiletamine hydrochloride and zolazepam hydrochloride.	a 1:1 mixture of tiletamine hydrochloride and zolazepam hydrochloride was tested on 39 polar bears in and near churchill, manitoba, canada during october 1983. the mean dose for satisfactory immobilization with a single injection was 5.1 mg/kg. bears showed signs of ataxia from 1-3 min following injection and were usually sitting within 4 min. the mean induction time, taken as the adoption of sternal recumbency, was 5.1 min. maximum relaxation was usually seen by about 20 min post-injection. the ...	2014	3981743
studies on the footpads of the polar bear (ursus maritimus) and their possible relevance to accident prevention.	the incidence of slipping accidents is unknown, but accident and emergency departments in the united kingdom probably treat over one million injuries per annum caused by slipping of the feet. many injuries to farm livestock are caused by slipping. previous research led to speculation that some animal species may have developed slip-resistant feet and the polar bear was chosen for a study of adaption to a slippery environment. feet were photographed and a footpad was sectioned and examined by lig ...	2014	4078456
extraction and analysis of cortisol from human and monkey hair.	the stress hormone cortisol (cort) is slowly incorporated into the growing hair shaft of humans, nonhuman primates, and other mammals. we developed and validated a method for cort extraction and analysis from rhesus monkey hair and subsequently adapted this method for use with human scalp hair. in contrast to cort "point samples" obtained from plasma or saliva, hair cort provides an integrated measure of hypothalamic-pituitary-adrenocortical (hpa) system activity, and thus physiological stress, ...	2014	24513702
idiosyncratic responses of grizzly bear habitat to climate change based on projected food resource changes.	climate change vulnerability assessments for species of conservation concern often use species distribution and ecological niche modeling to project changes in habitat. one of many assumptions of these approaches is that food web dependencies are consistent in time and environmental space. species at higher trophic levels that rely on the availability of species at lower trophic levels as food may be sensitive to extinction cascades initiated by changes in the habitat of key food resources. here ...	2014	25154102
zebra-borne equine herpesvirus type 1 (ehv-1) infection in non-african captive mammals.	equine herpesvirus type 1 (ehv-1) was detected in an indian rhinoceros (rhinoceros unicornis), which was euthanized because of severe neurological disease. encephalitis was suspected and ehv-1 dna was detected in brain, lung, and spleen tissues. the viral ir6 protein was detected in lung tissues by western blot analysis. phylogenetic analyses of ehv-1 sequences amplified from various tissues was nearly identical to one recently described that resulted in both non-fatal and fatal encephalitis in ...	2014	24440374
levels and trends of pbdes and hbcds in the global environment: status at the end of 2012.	in this paper, we have compiled and reviewed the most recent literature, published in print or online from january 2010 to december 2012, relating to the human exposure, environmental distribution, behaviour, fate and concentration time trends of polybrominated diphenyl ether (pbde) and hexabromocyclododecane (hbcd) flame retardants, in order to establish their current trends and priorities for future study. more data are now becoming available for remote areas not previously studied, indian oce ...	2014	24486972
comparative hepatic in vitro depletion and metabolite formation of major perfluorooctane sulfonate precursors in arctic polar bear, beluga whale, and ringed seal.	perfluorooctane sulfonate (pfos) has been reported to be among the most concentrated persistent organic pollutants in arctic marine wildlife. the present study examined the in vitro depletion of major pfos precursors, n-ethyl-perfluorooctane sulfonamide (n-etfosa) and perfluorooctane sulfonamide (fosa), as well as metabolite formation using an assay based on enzymatically viable liver microsomes for three top arctic marine mammalian predators, polar bear (ursus maritimus), beluga whale (delphina ...	2014	25048910
application of the luminometric methylation assay to ecological species: tissue quality requirements and a survey of dna methylation levels in animals.	the luminometric methylation assay (luma) measures global dna methylation. luma depends on digestion of dna with methyl-sensitive and methyl-insensitive restriction enzymes, followed by pyrosequencing. until recently, luma has been principally used for biomedical research. here, we use chickens as a model to investigate sample quality issues relating to luma and then apply the method to ecological species. first, we assessed the effect of tissue storage conditions on dna methylation values. this ...	2014	24576185
occurrence and genotypic analysis of trichinella species in alaska marine-associated mammals of the bering and chukchi seas.	the zoonotic parasite trichinella is the causative agent of trichinellosis outbreaks in the circumpolar arctic. subsistence communities are particularly prone to trichinellosis due to traditional meat preparation methods and regional presence of a freeze-tolerant trichinella species (trichinella nativa). this study is the first application of a validated artificial digestion method in determining incidence of trichinella sp. in alaskan mammals. infection incidence in pinniped species (erignathus ...	2014	24373515
assessment of neurotoxic effects of mercury in beluga whales (delphinapterus leucas), ringed seals (pusa hispida), and polar bears (ursus maritimus) from the canadian arctic.	marine mammals are indicator species of the arctic ecosystem and an integral component of the traditional inuit diet. the potential neurotoxic effects of increased mercury (hg) in beluga whales (delphinapterus leucas), ringed seals (pusa hispida), and polar bears (ursus maritimus) are not clear. we assessed the risk of hg-associated neurotoxicity to these species by comparing their brain hg concentrations with threshold concentrations for toxic endpoints detected in laboratory animals and field ...	2015	24958011
ursidibacter maritimus gen. nov., sp. nov. and ursidibacter arcticus sp. nov., two new members of the family pasteurellaceae isolated from the oral cavity of bears.	thirty-three suspected strains of the family pasteurellaceae isolated from the oral cavity of polar and brown bears were characterized by genotypic and phenotypic tests. phylogenetic analysis of partial 16s rrna gene and rpob sequences showed that the investigated isolates formed two closely related monophyletic groups, representing two novel species of a new genus. based on 16s rrna gene sequence comparison bibersteinia trehalosi was the closest related species with a validly published name, wi ...	2015	26220443
organophosphorous flame retardants in biota from svalbard, norway.	eight arctic species, including fish, birds and mammals, from diverse habitats (marine and terrestrial) within the svalbard archipelago, norway, were screened for 14 organophosphorus flame retardant (pfr) compounds. ten pfrs were detected: tris(2-chloroethyl)phosphate (tcep), tris(2-chloroisopropyl)phosphate (tcipp), tris(1,3-dichloro-2-propyl)phosphate (tdcipp), triphenyl phosphate (tphp); 2-ethylhexyl diphenyl phosphate (ehdpp); tris(2-butoxyethyl)phosphate (tboep); tritolyl phosphate (tcrp); ...	2015	26453403
genome-wide search identifies 1.9 mb from the polar bear y chromosome for evolutionary analyses.	the male-inherited y chromosome is the major haploid fraction of the mammalian genome, rendering y-linked sequences an indispensable resource for evolutionary research. however, despite recent large-scale genome sequencing approaches, only a handful of y chromosome sequences have been characterized to date, mainly in model organisms. using polar bear (ursus maritimus) genomes, we compare two different in silico approaches to identify y-linked sequences: 1) similarity to known y-linked genes and ...	2015	26019166
no need to replace an "anomalous" primate (primates) with an "anomalous" bear (carnivora, ursidae).	by means of mitochondrial 12s rrna sequencing of putative "yeti", "bigfoot", and other "anomalous primate" hair samples, a recent study concluded that two samples, presented as from the himalayas, do not belong to an "anomalous primate", but to an unknown, anomalous type of ursid. that is, that they match 12s rrna sequences of a fossil polar bear (ursusmaritimus), but neither of modern polar bears, nor of brown bears (ursusarctos), the closest relative of polar bears, and one that occurs today i ...	2015	25829853
recent progress on our understanding of the biological effects of mercury in fish and wildlife in the canadian arctic.	this review summarizes our current state of knowledge regarding the potential biological effects of mercury (hg) exposure on fish and wildlife in the canadian arctic. although hg in most freshwater fish from northern canada was not sufficiently elevated to be of concern, a few lakes in the northwest territories and nunavut contained fish of certain species (e.g. northern pike, arctic char) whose muscle hg concentrations exceeded an estimated threshold range (0.5-1.0 μg g(-1) wet weight) within w ...	2015	24935263
the functionality of the gastrointestinal microbiome in non-human animals.	due to the significance of the microbiome on human health, much of the current data available regarding microbiome functionality is centered on human medicine. for agriculturally important taxa, the functionality of gastrointestinal bacteria has been studied with the primary goals of improving animal health and production performance. with respect to cattle, the digestive functions of bacteria in cattle are unarguably critical to digestion and positively impact production performance. conversely ...	2015	26552373
[wild mammals of the grand duchy of lithuania in the works of jean-emmanuel gilibert].	among the many topics of lively scientific work that jean emmanuel gilibert (1741-1814) conducted in grodno and vilnius, an important place is occupied by his observations of wild mammals. royal patronage and care from antoni tyzenhauz, treasurer of the grand duchy of lithuania and the governor of grodno, allowed gilibert to keep and observe wild fauna captured by royal services in royal forests, including białowieża primeval forest. such was an origin of a female bison kept by gilibert in grodn ...	2015	26445747
implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming arctic.	we provide an expansive analysis of polar bear (ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. we sought to evaluate whether their genetic diversity and structure have changed over this period of habitat decline, how their current genetic patterns compare with past patterns, and how genetic demography changed with ancient fluctuations in climate. characterizing their circumpolar genetic structure using microsatellite data, we defin ...	2015	25562525
increased land use by chukchi sea polar bears in relation to changing sea ice conditions.	recent observations suggest that polar bears (ursus maritimus) are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. we used location data from female polar bears fit with satellite radio collars to compare land use patterns in the chukchi sea between two periods (1986-1995 and 2008-2013) when substantial summer sea-ice loss occurred. in both ...	2015	26580809
erratum to: a review of infectious agents in polar bears (ursus maritimus) and their long-term ecological relevance.		2015	26446003
the energetic value of land-based foods in western hudson bay and their potential to alleviate energy deficits of starving adult male polar bears.	climate change is predicted to expand the ice-free season in western hudson bay and when it grows to 180 days, 28-48% of adult male polar bears are projected to starve unless nutritional deficits can be offset by foods consumed on land. we updated a dynamic energy budget model developed by molnar et al. to allow influx of additional energy from novel terrestrial foods (lesser snow geese, eggs, caribou) that polar bears currently consume as part of a mixed diet while on land. we calculated the un ...	2015	26061693
mercury and cortisol in western hudson bay polar bear hair.	non-invasive methods of assessing animal health and life history are becoming increasingly popular in wildlife research; hair samples from polar bears (ursus maritimus), are being used to study an ever broader range of anthropogenic and endocrine compounds. a number of contaminants are known to disrupt endocrine function in polar bears. however, the relationship between mercury and cortisol remains unknown, although mercury is an endocrine disruptor in other species. here, we examine the relatio ...	2015	26044932
modeling diffusion in colloidal suspensions by dynamical density functional theory using fundamental measure theory of hard spheres.	we study the dynamics of colloidal suspensions of hard spheres that are subject to brownian motion in the overdamped limit. we obtain the time evolution of the self- and distinct parts of the van hove function by means of dynamical density functional theory. the free-energy model for the hard-sphere fluid that we use is the very accurate white bear ii version of rosenfeld's fundamental measure theory. however, in order to remove interactions within the self-part of the van hove function, a nontr ...	2015	26382387
anti-nmda receptor encephalitis in the polar bear (ursus maritimus) knut.	knut the polar bear of the berlin zoological garden drowned in 2011 following seizures and was diagnosed as having suffered encephalitis of unknown etiology after exhaustive pathogen screening. using the diagnostic criteria applied to human patients, we demonstrate that knut's encephalitis is almost identical to anti-nmda receptor encephalitis which is a severe autoimmune disease representing the most common non-infectious encephalitis in humans. high concentrations of antibodies specific agains ...	2015	26313569
hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (ursus maritimus).	as a top predator in the arctic food chain, polar bears (ursus maritimus) are exposed to high levels of persistent organic pollutants (pops). because several of these compounds have been reported to alter endocrine pathways, such as the steroidogenesis, potential disruption of the sex steroid synthesis by pops may cause implications for reproduction by interfering with ovulation, implantation and fertility. blood samples were collected from 15 female polar bears in svalbard (norway) in april 200 ...	2015	25725300
polar bear population dynamics in the southern beaufort sea during a period of sea ice decline.	in the southern beaufort sea of the united states and canada, prior investigations have linked declines in summer sea ice to reduced physical condition, growth, and survival of polar bears (ursus maritimus). combined with projections of population decline due to continued climate warming and the ensuing loss of sea ice habitat, those findings contributed to the 2008 decision to list the species as threatened under the u.s. endangered species act. here, we used mark-recapture models to investigat ...	2015	26214910
animal physiology. summer declines in activity and body temperature offer polar bears limited energy savings.	polar bears (ursus maritimus) summer on the sea ice or, where it melts, on shore. although the physiology of "ice" bears in summer is unknown, "shore" bears purportedly minimize energy losses by entering a hibernation-like state when deprived of food. such a strategy could partially compensate for the loss of on-ice foraging opportunities caused by climate change. however, here we report gradual, moderate declines in activity and body temperature of both shore and ice bears in summer, resembling ...	2015	26185248
ironic effects as reflexive responses: evidence from word frequency effects on involuntary subvocalizations.	in ironic processing, one is more likely to think about something (e.g., white bears) when instructed to not think about that thing. to further investigate this phenomenon involving cognitive control, in the reflexive imagery task (rit), participants are instructed to not subvocalize the names of visual objects. on the majority of the trials, participants fail to suppress such subvocalizations. this finding supports theorizing that conscious thoughts can be triggered by external stimuli in a man ...	2015	26005914
fundamental measure theory for the electric double layer: implications for blue-energy harvesting and water desalination.	capacitive mixing (capmix) and capacitive deionization (cdi) are promising candidates for harvesting clean, renewable energy and for the energy efficient production of potable water, respectively. both capmix and cdi involve water-immersed porous carbon (supercapacitors) electrodes at voltages of the order of hundreds of millivolts, such that counter-ionic packing is important for the electric double layer (edl) which forms near the surfaces of these porous materials. thus, we propose a density ...	2015	25923717
himalayan 'yeti' dna: polar bear or dna degradation? a comment on 'genetic analysis of hair samples attributed to yeti' by sykes et al. (2014).		2015	25520353
brain region-specific perfluoroalkylated sulfonate (pfsa) and carboxylic acid (pfca) accumulation and neurochemical biomarker responses in east greenland polar bears (ursus maritimus).	perfluoroalkyl substances (pfass) is a growing class of contaminants in the arctic environment, and include the established perfluorinated sulfonates (pfsas; especially perfluorooctane sulfonate (pfos)) and carboxylic acids (pfcas). pfsas and pfcas of varying chain length have been reported to bioaccumulate in lipid rich tissues of the brain among other tissues such as liver, and can reach high concentrations in top predators including the polar bear. pfca and pfsa bioaccummulation in the brain ...	2015	25682255
environmental contaminants activate human and polar bear (ursus maritimus) pregnane x receptors (pxr, nr1i2) differently.	many persistent organic pollutants (pops) accumulate readily in polar bears because of their position as apex predators in arctic food webs. the pregnane x receptor (pxr, formally nr1i2, here proposed to be named promiscuous xenobiotic receptor) is a xenobiotic sensor that is directly involved in metabolizing pathways of a wide range of environmental contaminants.	2015	25680588
free energy calculations of crystalline hard sphere complexes using density functional theory.	recently developed fundamental measure density functional theory (fmt) is used to study binary hard sphere (hs) complexes in crystalline phases. by comparing the excess free energy, pressure, and phase diagram, we show that the fundamental measure functional yields good agreements to the available simulation results of ab, ab2, and ab13 crystals. furthermore, we use this functional to study the hs models of five binary crystals, cu5zr(c15b), cu51zr14(β), cu10zr7(ϕ), cuzr(b2), and cuzr2(c11b), wh ...	2015	25496266
thyroid hormones and deiodinase activity in plasma and tissues in relation to high levels of organohalogen contaminants in east greenland polar bears (ursus maritimus).	previous studies have shown relationships between organohalogen contaminants (ohcs) and circulating levels of thyroid hormones (ths) in arctic wildlife. however, there is a lack of knowledge concerning the possible functional effects of ohcs on th status in target tissues for th-dependent activity. the relationships between circulating (plasma) levels of ohcs and various th variables in plasma as well as in liver, muscle and kidney tissues from east greenland sub-adult polar bears (ursus maritim ...	2015	25460663
elevated accumulation of parabens and their metabolites in marine mammals from the united states coastal waters.	the widespread exposure of humans to parabens present in personal care products is well-known. nevertheless, little is known about the accumulation of parabens in marine organisms. in this study, six parabens and four common metabolites of parabens were measured in 121 tissue samples from eight species of marine mammals collected along the coastal waters of florida, california, washington, and alaska. methyl paraben (mep) was the predominant compound found in the majority of the marine mammal ti ...	2015	26379094
the effects of sleep deprivation on dissociation and profiles of mood, and its association with biochemical changes.	sleep deprivation is a method, which has being used in order to comprehend the functions of sleep both in healthy individuals and for the patients of depression with in treatment, for a long time. the objective of our present study is to examine the relation between hormonal values, which are known for being related to the effects of these said changes determined in the mood, dissociation and thought suppression in healthy individuals after one night of sleep deprivation implementation.	2015	28360682
establishing a definition of polar bear (ursus maritimus) health: a guide to research and management activities.	the meaning of health for wildlife and perspectives on how to assess and measure health, are not well characterized. for wildlife at risk, such as some polar bear (ursus maritimus) subpopulations, establishing comprehensive monitoring programs that include health status is an emerging need. environmental changes, especially loss of sea ice habitat, have raised concern about polar bear health. effective and consistent monitoring of polar bear health requires an unambiguous definition of health. w ...	2015	25679818
penile density and globally used chemicals in canadian and greenland polar bears.	industrially produced chemicals have been a major environmental concern across our entire globe since the onset of rapid industrial development around the early 1900. many of the substances being used are known to be endocrine disrupting chemicals (edcs) and are also known to be long-range dispersed and to biomagnify to very high concentrations in the tissues of arctic apex predators such as polar bears (ursus maritimus). a major concern relating to edcs is their effects on vital organ-tissues s ...	2015	25601730
population substructure and space use of foxe basin polar bears.	climate change has been identified as a major driver of habitat change, particularly for sea ice-dependent species such as the polar bear (ursus maritimus). population structure and space use of polar bears have been challenging to quantify because of their circumpolar distribution and tendency to range over large areas. knowledge of movement patterns, home range, and habitat is needed for conservation and management. this is the first study to examine the spatial ecology of polar bears in the f ...	2015	26306171
correction: implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming arctic.		2015	26273835
web-based acceptance and commitment therapy for depressive symptoms with minimal support: a randomized controlled trial.	low-intensity interventions for people suffering from depressive symptoms are highly desirable. the aim of the present study was to investigate the outcomes of a web-based acceptance and commitment therapy (act)-based intervention without face-to-face contact for people suffering from depressive symptoms. participants (n = 39) with depressive symptoms were randomly assigned to an internet-delivered acceptance and commitment therapy (iact) intervention or a waiting list control condition (wlc). p ...	2015	26253644
polar bear mother-offspring interactions in maternity dens in captivity.	two female polar bears at dierenrijk zoo in the netherlands were monitored at their maternity den one day before the birth of their cubs and three days postpartum. each bear was monitored for 96 hr to document behaviour and vocalisations. the goal was to obtain insight into the differences between the mother that lost her litter and the other that successfully reared her cubs. six groups of cub vocalisations were identified: comfort, discomfort, distress, nursing attempts, nursing, and no vocali ...	2015	26252623
genetic signatures of adaptation revealed from transcriptome sequencing of arctic and red foxes.	the genus vulpes (true foxes) comprises numerous species that inhabit a wide range of habitats and climatic conditions, including one species, the arctic fox (vulpes lagopus) which is adapted to the arctic region. a close relative to the arctic fox, the red fox (vulpes vulpes), occurs in subarctic to subtropical habitats. to study the genetic basis of their adaptations to different environments, transcriptome sequences from two arctic foxes and one red fox individual were generated and analyzed ...	2015	26250829
distance measures and optimization spaces in quantitative fatty acid signature analysis.	quantitative fatty acid signature analysis has become an important method of diet estimation in ecology, especially marine ecology. controlled feeding trials to validate the method and estimate the calibration coefficients necessary to account for differential metabolism of individual fatty acids have been conducted with several species from diverse taxa. however, research into potential refinements of the estimation method has been limited. we compared the performance of the original method of ...	2015	25859330
novel brominated flame retardants and dechlorane plus in greenland air and biota.	following the ban of polybrominated diphenyl ethers, other halogenated flame retardants (frs) might be used increasingly. this study has analyzed hexabromocyclododecane (hbcd), 1,2-bis(2,4,6-tribromophenoxy)-ethane (btbpe), 2,3-dibromopropyl-2,4,6-tribromophenyl ether (dpte) and dechloraneplus (dp) in greenland air over the course of a year. moreover, btbpe, dpte, dp, 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (tbb), bis(2-ethylhexyl) tetrabromophthalate (tbph) and decabromodiphenylethane (dbdpe) w ...	2015	25463724
physiologically-based pharmacokinetic modelling of distribution, bioaccumulation and excretion of pops in greenland sledge dogs (canis familiaris).	we used pbpk (physiologically-based pharmacokinetic) modelling to investigate distribution, bioaccumulation and excretion of the seven pops (persistent organic pollutants) cb-99, cb-153, hcb, oxychlordane, p,p'-dde, bde-47 and bde-99 in 4 adult captive greenland sledge dog (canis familiaris) bitches fed minke whale (balaenoptera acuterostrata) blubber for 500-635 days. the pbpk modelled pop concentrations in adipose tissue, liver, kidney and plasma were mostly within a factor 2 of actual measure ...	2015	26210746
the role of pleistocene glaciations in shaping the evolution of polar and brown bears. evidence from a critical review of mitochondrial and nuclear genome analyses.	in this report, i review recent molecular studies dealing with the origin and evolution of polar bears (ursus maritimus), with special emphasis on their relationships with brown bears (u. arctos). on the basis of mitochondrial and nuclear data, different hypotheses have been proposed, including rapid morphological differentiation of u. maritimus, genetic introgression from u. arctos into u. maritimus, or inversely from u. maritimus into u. arctos, involving either male- or female-mediated gene f ...	2015	26026577
genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears.	polar bears are an arctic, marine adapted species that is closely related to brown bears. genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. however, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the admiralty, baranof and chichagof islands (abc islands) of alaska. here, we present an analysis of data from a large panel of polar bear and brown bear ge ...	2015	25490862
an evolutionarily young polar bear (ursus maritimus) endogenous retrovirus identified from next generation sequence data.	transcriptome analysis of polar bear (ursus maritimus) tissues identified sequences with similarity to porcine endogenous retroviruses (perv). based on these sequences, four proviral copies and 15 solo long terminal repeats (ltrs) of a newly described endogenous retrovirus were characterized from the polar bear draft genome sequence. closely related sequences were identified by pcr analysis of brown bear (ursus arctos) and black bear (ursus americanus) but were absent in non-ursinae bear species ...	2015	26610552
y-chromosomal testing of brown bears (ursus arctos): validation of a multiplex pcr-approach for nine strs suitable for fecal and hair samples.	high-resolution y-chromosomal markers have been applied to humans and other primates to study population genetics, migration, social structures and reproduction. y-linked markers allow the direct assessment of the genetic structure and gene flow of uniquely male inherited lineages and may also be useful for wildlife conservation and forensics, but have so far been available only for few wild species. thus, we have developed two multiplex pcr reactions encompassing nine y-str markers identified f ...	2015	26264959
introgressive hybridization: brown bears as vectors for polar bear alleles.	the dynamics and consequences of introgression can inform about numerous evolutionary processes. biologists have therefore long been interested in hybridization. one challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. in this issue of molecular ecology, cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one american black bear. polar bear alleles are found to be introgr ...	2015	25775930
growth trajectories in the cave bear and its extant relatives: an examination of ontogenetic patterns in phylogeny.	the study of postnatal ontogeny can provide insights into evolution by offering an understanding of how growth trajectories have evolved resulting in adult morphological disparity. the ursus lineage is a good subject for studying cranial and mandibular shape and size variation in relation to postnatal ontogeny and phylogeny because it is at the same time not diverse but the species exhibit different feeding ecologies. cranial and mandibular shapes of ursus arctos (brown bear), u. maritimus (pola ...	2015	26525575
enhanced biological processes associated with alopecia in polar bears (ursus maritimus).	populations of wildlife species worldwide experience incidents of mass morbidity and mortality. primary or secondary drivers of these events may escape classical detection methods for identifying microbial insults, toxin exposure, or additional stressors. in 2012, 28% of polar bears sampled in a study in the southern beaufort sea region of alaska had varying degrees of alopecia that was concomitant with reduced body condition. concurrently, elevated numbers of sick or dead ringed seals were dete ...	2015	26005754
mercury in the marine environment of the canadian arctic: review of recent findings.	this review summarizes data and information which have been generated on mercury (hg) in the marine environment of the canadian arctic since the previous canadian arctic contaminants assessment report (cacar) was released in 2003. much new information has been collected on hg concentrations in marine water, snow and ice in the canadian arctic. the first measurements of methylation rates in arctic seawater indicate that the water column is an important site for hg methylation. arctic marine water ...	2015	24953756
physiologically-based pharmacokinetic modelling of immune, reproductive and carcinogenic effects from contaminant exposure in polar bears (ursus maritimus) across the arctic.	polar bears (ursus maritimus) consume large quantities of seal blubber and other high trophic marine mammals and consequently have some of the highest tissue concentrations of organohalogen contaminants (ohcs) among arctic biota. in the present paper we carried out a risk quotient (rq) evaluation on ohc-exposed polar bears harvested from 1999 to 2008 and from 11 circumpolar subpopulations spanning from alaska to svalbard in order to evaluate the risk of ohc-mediated reproductive effects (embryot ...	2015	25825130
a review of infectious agents in polar bears (ursus maritimus) and their long-term ecological relevance.	disease was a listing criterion for the polar bear (ursus maritimus) as threatened under the endangered species act in 2008; it is therefore important to evaluate the current state of knowledge and identify any information gaps pertaining to diseases in polar bears. we conducted a systematic literature review focused on infectious agents and associated health impacts identified in polar bears. overall, the majority of reports in free-ranging bears concerned serosurveys or fecal examinations with ...	2015	25791679
trichinella spp. imported with live animals and meat.	nematodes of the genus trichinella are widely distributed throughout the world in omnivorous and carnivorous animals (mammals, birds, and reptiles) and in incidental hosts. to prevent the transmission of these zoonotic parasites to humans, meat samples from trichinella spp. susceptible animals are tested at the slaughterhouse or in game processing plants. the aim of the present review was to collect documented cases on trichinella infected animals, meat, or meat derived products which reached th ...	2015	25754352
prevalence and spatio-temporal variation of an alopecia syndrome in polar bears (ursus maritimus) of the southern beaufort sea.	alopecia (hair loss) has been observed in several marine mammal species and has potential energetic consequences for sustaining a normal core body temperature, especially for arctic marine mammals routinely exposed to harsh environmental conditions. polar bears (ursus maritimus) rely on a thick layer of adipose tissue and a dense pelage to ameliorate convective heat loss while moving between sea ice and open water. from 1998 to 2012, we observed an alopecia syndrome in polar bears from the south ...	2015	25375943
polyhalogenated compounds (pcbs, chlordanes, hcb and bfrs) in four polar bears (ursus maritimus) that swam malnourished from east greenland to iceland.	levels of organohalogen compounds (pcbs, chlordane, pbb 153, pbdes, hcb) were determined in adipose tissue, liver, kidney and muscle of four polar bears which swam and/or drifted to iceland in extremely malnourished condition. since the colonization in the 9th century polar bears have been repeatedly observed in iceland. however, in recent years three of the animals have clearly left their natural habitat in poor condition in may or june, i.e. at the end of the major feeding season. the fourth b ...	2015	26172596
pros and cons of methylation-based enrichment methods for ancient dna.	the recent discovery that dna methylation survives in fossil material provides an opportunity for novel molecular approaches in palaeogenomics. here, we apply to ancient dna extracts the probe-independent methylated binding domains (mbd)-based enrichment method, which targets dna molecules containing methylated cpgs. using remains of a palaeo-eskimo saqqaq individual, woolly mammoths, polar bears and two equine species, we confirm that dna methylation survives in a variety of tissues, environmen ...	2015	26134828
thinking about white bears: fertility issues in young breast cancer survivors.		2015	25200632
design of a 9k illumina beadchip for polar bears (ursus maritimus) from rad and transcriptome sequencing.	single-nucleotide polymorphisms (snps) offer numerous advantages over anonymous markers such as microsatellites, including improved estimation of population parameters, finer-scale resolution of population structure and more precise genomic dissection of quantitative traits. however, many snps are needed to equal the resolution of a single microsatellite, and reliable large-scale genotyping of snps remains a challenge in nonmodel species. here, we document the creation of a 9k illumina infinium ...	2015	25187336
individual effects of seasonal changes, visitor density, and concurrent bear behavior on stereotypical behaviors in captive polar bears (ursus maritimus).	stereotypical behaviors in captive polar bears (ursus maritimus) can be detrimental to their welfare. these behaviors can be reduced through enrichment programs but are often not completely eliminated, so identifying potential triggers is important. the present study investigated the influences of seasonal changes, visitor density, and concurrent bear activity on stereotypical behaviors exhibited by 3 captive polar bears at the toronto zoo. all bears exhibited these behaviors; however, individua ...	2015	24933263
the relationship between thought suppression and retrieval-induced forgetting: an analysis of witness memories.	the aim of the present research was to examine the relationship between individual differences in thought suppression and retrieval-induced forgetting (rif) in witness-like situations. we predicted that people who are more prone to suppress undesired thoughts and memories would demonstrate a stronger rif effect. consistent with findings obtained in a us sample (blumberg in personal individ differ 29:943-950, 2000), results of a preliminary study (study 1) confirmed the three-factor structure of ...	2015	25064740
[the possibility of using high resolution satellite images for detection of marine mammals].	the possibility of using modern systems of remote sensing in the optical range from high spatial resolution satellites for detection of marine mammals and traces of their activity is investigated. an image obtained by the geoeye satellite within the feac project was used for the analysis. the image covers herald island and adjacent waters, which are a part of the wrangel island reserve, during the seasonal thaw (june 2009). it is shown that marine mammals (polar bears, walruses, and whales) can ...	2016	23789427
assessing polar bear (ursus maritimus) population structure in the hudson bay region using snps.	defining subpopulations using genetics has traditionally used data from microsatellite markers to investigate population structure; however, single-nucleotide polymorphisms (snps) have emerged as a tool for detection of fine-scale structure. in hudson bay, canada, three polar bear (ursus maritimus) subpopulations (foxe basin (fb), southern hudson bay (sh), and western hudson bay (wh)) have been delineated based on mark-recapture studies, radiotelemetry and satellite telemetry, return of marked a ...	2016	28031799
involuntary symbol manipulation (pig latin) from external control: implications for thought suppression.	in ironic processing, one is more likely to think about something (e.g., white bears) when instructed to not think about that thing. entry into consciousness of such content may be automatic, reflecting the 'encapsulated' nature of the generation of conscious contents. based on this research, the reflexive imagery task (rit) reveals that, following the activation of action sets, conscious contents can arise involuntarily and systematically in response to external stimuli. in the most basic versi ...	2016	27043254
a cluster of three cases of trichinellosis linked to bear meat consumption in the arctic.	we report here three cases of trichinellosis due to polar bear meat consumption in east greenland. in the past 20 years, 31 cases of trichinellosis have been reported in french travellers to the arctic (north quebec, nunavut and greenland) who consumed undercooked meat from black, brown, or polar bears. if local communities are increasingly becoming aware of the risk of trichinellosis, travellers visiting regions where bear meat is consumed should be informed of the risk of eating raw or non-hea ...	2016	27296583
evaluating random search strategies in three mammals from distinct feeding guilds.	searching allows animals to find food, mates, shelter and other resources essential for survival and reproduction and is thus among the most important activities performed by animals. theory predicts that animals will use random search strategies in highly variable and unpredictable environments. two prominent models have been suggested for animals searching in sparse and heterogeneous environments: (i) the lévy walk and (ii) the composite correlated random walk (ccrw) and its associated area-re ...	2016	27354185
rapid environmental change drives increased land use by an arctic marine predator.	in the arctic ocean's southern beaufort sea (sb), the length of the sea ice melt season (i.e., period between the onset of sea ice break-up in summer and freeze-up in fall) has increased substantially since the late 1990s. historically, polar bears (ursus maritimus) of the sb have mostly remained on the sea ice year-round (except for those that came ashore to den), but recent changes in the extent and phenology of sea ice habitat have coincided with evidence that use of terrestrial habitat is in ...	2016	27249673
modeling population-level consequences of polychlorinated biphenyl exposure in east greenland polar bears.	polychlorinated biphenyls (pcbs) can cause endocrine disruption, cancer, immunosuppression, or reproductive failure in animals. we used an individual-based model to explore whether and how pcb-associated reproductive failure could affect the dynamics of a hypothetical polar bear (ursus maritimus) population exposed to pcbs to the same degree as the east greenland subpopulation. dose-response data from experimental studies on a surrogate species, the mink (mustela vision), were used in the absenc ...	2016	26289812
current-use pesticides in seawater and their bioaccumulation in polar bear-ringed seal food chains of the canadian arctic.	the distribution of current-use pesticides (cups) in seawater and their trophodynamics were investigated in 3 canadian arctic marine food chains. the greatest ranges of dissolved-phase concentrations in seawater for each cup were endosulfan sulfate (less than method detection limit (mdl) to 19 pg l(-1) ) > dacthal (0.76-15 pg l(-1) ) > chlorpyrifos (less than mdl to 8.1 pg l(-1) ) > pentachloronitrobenzene (less than mdl to 2.6 pg l(-1) ) > α-endosulfan (0.20-2.3 pg l(-1) ). bioaccumulation fact ...	2016	27027986
observation of emerging per- and polyfluoroalkyl substances (pfass) in greenland marine mammals.	the present pilot study examined emerging per- and polyfluoroalkyl substances (pfass), i.e., a suite of short chain perfluoroalkyl acids (pfaas), pfaa precursors and replacement chemicals, and legacy pfass (long chain length pfaas) in livers from ringed seals, polar bears and, for the first time, killer whales from east greenland collected in 2012-2013. among the emerging pfass, perfluorobutanesulfonic acid (pfbs) and f-53b (a chlorinated polyfluorinated ether sulfonic acid) were detected in arc ...	2016	26610298
novel finding of widespread occurrence and accumulation of bisphenol a diglycidyl ethers (badges) and novolac glycidyl ethers (noges) in marine mammals from the united states coastal waters.	bisphenol a diglycidyl ether (badge)- and bisphenol f diglycidyl ether (bfdge)-based epoxy resins have a broad range of applications, including serving as inner coatings of food and beverage cans and as protective coatings in marine construction. prior to this study, no studies had examined the occurrence and bioaccumulation of badges or bfdges in aquatic organisms. in this study, badge, bfdge, and nine of their derivatives were determined in 121 tissue (liver, kidney, blubber, and brain) sample ...	2016	26800265
per- and polyfluoroalkyl substances (pfass) - new endocrine disruptors in polar bears (ursus maritimus)?	per- and polyfluoroalkyl substances (pfass) are emerging in the arctic and accumulate in brain tissues of east greenland (eg) polar bears. in vitro studies have shown that pfass might possess endocrine disrupting abilities and therefore the present study was conducted to investigate potential pfas induced alterations in brain steroid concentrations. the concentrations of eleven steroid hormones were determined in eight brain regions from ten eg polar bears. pregnenolone (pre), the dominant proge ...	2016	27692342
costs of locomotion in polar bears: when do the costs outweigh the benefits of chasing down terrestrial prey?	trade-offs between locomotory costs and foraging gains are key elements in determining constraints on predator-prey interactions. one intriguing example involves polar bears pursuing snow geese on land. as climate change forces polar bears to spend more time ashore, they may need to expend more energy to obtain land-based food. given that polar bears are inefficient at terrestrial locomotion, any extra energy expended to pursue prey could negatively impact survival. however, polar bears have bee ...	2016	27757238
taming the white bear: initial costs and eventual benefits of distractor inhibition.	previous research indicates that prior information about a target feature, such as its color, can speed search. can search also be speeded by knowing what a target willnotlook like? in the two experiments reported here, participants searched for target letters. prior to viewing search displays, participants were prompted either with the color in which one or more nontarget letters would appear (ignore trials) or with no information about the search display (neutral trials). critically, when part ...	2016	26893292
distinct mechanisms for distractor suppression and target facilitation.	it is well established that preparatory attention improves processing of task-relevant stimuli. although it is often more important to ignore task-irrelevant stimuli, comparatively little is known about preparatory attentional mechanisms for inhibiting expected distractions. here, we establish that distractor inhibition is not under the same top-down control as target facilitation. using a variant of the posner paradigm, participants were cued to either the location of a target stimulus, the loc ...	2016	26865606
circumpolar genetic structure and recent gene flow of polar bears: a reanalysis.	recently, an extensive study of 2,748 polar bears (ursus maritimus) from across their circumpolar range was published in plos one, which used microsatellites and mitochondrial haplotypes to apparently show altered population structure and a dramatic change in directional gene flow towards the canadian archipelago-an area believed to be a future refugium for polar bears as their southernmost habitats decline under climate change. although this study represents a major international collaborative ...	2016	26974333
a novel method for analysing key corticosteroids in polar bear (ursus maritimus) hair using liquid chromatography tandem mass spectrometry.	this paper presents the development and evaluation of a methodology for extraction, clean-up and analysis of three key corticosteroids (aldosterone, cortisol and corticosterone) in polar bear hair. such a methodology can be used to monitor stress biomarkers in polar bears and may provide as a useful tool for long-term and retrospective information. we developed a combined pressurized liquid extraction (ple)-solid phase extraction (spe) procedure for corticosteroid extraction and clean-up followe ...	2016	26945133
circumpolar contaminant concentrations in polar bears (ursus maritimus) and potential population-level effects.	polar bears (ursus maritimus) currently receive much attention in the context of global climate change. however, there are other stressors that might threaten the viability of polar bear populations as well, such as exposure to anthropogenic pollutants. lipophilic organic compounds bio-accumulate and bio-magnify in the food chain, leading to high concentrations at the level of top-predators. in arctic wildlife, including the polar bear, various adverse health effects have been related to interna ...	2016	27450999
demography of an apex predator at the edge of its range: impacts of changing sea ice on polar bears in hudson bay.	changes in the abundance and distribution of wildlife populations are common consequences of historic and contemporary climate change. some arctic marine mammals, such as the polar bear (ursus maritimus), may be particularly vulnerable to such changes due to the loss of arctic sea ice. we evaluated the impacts of environmental variation on demographic rates for the western hudson bay (wh), polar bear subpopulation from 1984 to 2011 using live-recapture and dead-recovery data in a bayesian implem ...	2016	27755745
environmental chemicals modulate polar bear (ursus maritimus) peroxisome proliferator-activated receptor gamma (pparg) and adipogenesis in vitro.	we studied interactions between polar bear peroxisome proliferator-activated receptor gamma (pbpparg) and selected compounds using a luciferase reporter assay and predictions through molecular docking. furthermore, we studied adipogenesis by liver and adipose tissue extracts from a polar bear and three synthetic mixtures of contaminants in murine 3t3-l1 preadipocytes and polar bear adipose tissue-derived stem cells (pbascs). pcb153 and p,p'-dde antagonized pbpparg, although their predicted recep ...	2016	27602593
geographical area and life history traits influence diet in an arctic marine predator.	global changes are thought to affect most arctic species, yet some populations are more at risk. today, the barents sea ecoregion is suffering the strongest sea ice retreat ever measured; and these changes are suspected to modify food access and thus diet of several species. biochemical diet tracers enable investigation of diet in species such as polar bears (ursus maritimus). we examined individual diet variation of female polar bears in svalbard, norway, and related it to year, season (spring ...	2016	27196700
hair mercury concentrations in western hudson bay polar bear family groups.	methylmercury is one of the more toxic forms of mercury (hg), the biomagnification of which is prevalent in the arctic where apex predators such as polar bears (ursus maritimus) can carry high loads. the maternal transfer of contaminants to offspring is a concern, as offspring may be particularly sensitive to the effects of environmental pollutants during early development. however, few studies of polar bears report on hg in dependent young. we examined hair total hg (thg) concentrations in 24 p ...	2016	27095340
demographic and traditional knowledge perspectives on the current status of canadian polar bear subpopulations.	subpopulation growth rates and the probability of decline at current harvest levels were determined for 13 subpopulations of polar bears (ursus maritimus) that are within or shared with canada based on mark-recapture estimates of population numbers and vital rates, and harvest statistics using population viability analyses (pva). aboriginal traditional ecological knowledge (tek) on subpopulation trend agreed with the seven stable/increasing results and one of the declining results, but disagreed ...	2016	27069588
immunotoxic effects of environmental pollutants in marine mammals.	due to their marine ecology and life-history, marine mammals accumulate some of the highest levels of environmental contaminants of all wildlife. given the increasing prevalence and severity of diseases in marine wildlife, it is imperative to understand how pollutants affect the immune system and consequently disease susceptibility. advancements and adaptations of analytical techniques have facilitated marine mammal immunotoxicology research. field studies, captive-feeding experiments and in vit ...	2016	26590481
concentrations and patterns of hydroxylated polybrominated diphenyl ethers and polychlorinated biphenyls in arctic foxes (vulpes lagopus) from svalbard.	concentrations and patterns of hydroxylated (oh) polybrominated diphenyl ethers (pbdes) and polychlorinated biphenyls (pcbs) were investigated in liver from arctic foxes (vulpes lagopus) sampled from svalbard 1997-2011 (n = 100). the most important oh-pbde in the arctic foxes was 6-oh-bde47 detected in 24% of the samples. relationships between 6-oh-bde47, δ(13)c and bde47 suggest that 6-oh-bde47 residues in arctic foxes are related to marine dietary input, while the relative importance of the me ...	2016	27267742
the relationship between clinical characteristics, metacognitive appraisals, and cognitive insight in patients with obsessive-compulsive disorder.	cognitive insight, a recently developed insight measure, refers to metacognitive processes of the re-evaluation and correction of distorted beliefs and misinterpretations. however, to the best of the authors' knowledge, no study has specifically examined cognitive insight, demographics, psychopathological variables, and distorted beliefs in ocd.	2016	27249043
state-space models' dirty little secrets: even simple linear gaussian models can have estimation problems.	state-space models (ssms) are increasingly used in ecology to model time-series such as animal movement paths and population dynamics. this type of hierarchical model is often structured to account for two levels of variability: biological stochasticity and measurement error. ssms are flexible. they can model linear and nonlinear processes using a variety of statistical distributions. recent ecological ssms are often complex, with a large number of parameters to estimate. through a simulation st ...	2016	27220686