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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 ...201626974333
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 ...201626945133
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 ...201626893292
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 ...201626865606
evaluation of hepatic biotransformation of polybrominated diphenyl ethers in the polar bear (ursus maritimus).polar bears are at the top of the arctic marine food chain and are subject to exposure and bioaccumulation of environmental chemicals of concern such as polybrominated diphenyl ethers (pbdes), which were widely used as flame retardants. the aim of the present study was to evaluate the in vitro oxidative metabolism of 2,2',4,4'-tetrabrominated diphenyl ether (bde-47) and 2,2',4,4',5-pentabrominated diphenyl ether (bde-99) by polar bear liver microsomes. the identification and quantification of th ...201626745384
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 ...201626590481
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 ...201627692342
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 ...201627757238
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 ...201627450999
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 ...201627755745
using simulation to evaluate wildlife survey designs: polar bears and seals in the chukchi sea.logistically demanding and expensive wildlife surveys should ideally yield defensible estimates. here, we show how simulation can be used to evaluate alternative survey designs for estimating wildlife abundance. specifically, we evaluate the potential of instrument-based aerial surveys (combining infrared imagery with high-resolution digital photography to detect and identify species) for estimating abundance of polar bears and seals in the chukchi sea. we investigate the consequences of differe ...201626909183
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 ...201628031799
conservation status of polar bears (ursus maritimus) in relation to projected sea-ice declines.loss of arctic sea ice owing to climate change is the primary threat to polar bears throughout their range. we evaluated the potential response of polar bears to sea-ice declines by (i) calculating generation length (gl) for the species, which determines the timeframe for conservation assessments; (ii) developing a standardized sea-ice metric representing important habitat; and (iii) using statistical models and computer simulation to project changes in the global population under three approach ...201627928000
allee effect in polar bears: a potential consequence of polychlorinated biphenyl contamination.polar bears (ursus maritimus) from east greenland and svalbard exhibited very high concentrations of polychlorinated biphenyls (pcbs) in the 1980s and 1990s. in svalbard, slow population growth during that period was suspected to be linked to pcb contamination. in this case study, we explored how pcbs could have impacted polar bear population growth and/or male reproductive success in svalbard during the mid-1990s by reducing the fertility of contaminated males. a dose-response relationship link ...201627903868
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 ...201627354185
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 ...201627027986
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 ...201626610298
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 ...201626800265
dietary habits of polar bears in foxe basin, canada: possible evidence of a trophic regime shift mediated by a new top predator.polar bear (ursus maritimus) subpopulations in several areas with seasonal sea ice regimes have shown declines in body condition, reproductive rates, or abundance as a result of declining sea ice habitat. in the foxe basin region of nunavut, canada, the size of the polar bear subpopulation has remained largely stable over the past 20 years, despite concurrent declines in sea ice habitat. we used fatty acid analysis to examine polar bear feeding habits in foxe basin and thus potentially identify ...201627547372
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 ...201627249673
sarcocystis caninum and sarcocystis svanai n. spp. (apicomplexa: sarcocystidae) associated with severe myositis and hepatitis in the domestic dog (canis familiaris).there are several reports of sarcocystis sarcocysts in muscles of dogs, but these species have not been named. additionally, there are two reports of sarcocystis neurona in dogs. here, we propose two new names, sarcocystis caninum, and sarcocystis svanai for sarcocysts associated with clinical muscular sarcocystosis in four domestic dogs (canis familiaris), one each from montana and colorado in the usa, and two from british columbia, canada. only the sarcocyst stage was identified. most of the s ...201625256157
low density of top predators (seabirds and marine mammals) in the high arctic pack ice.the at-sea distribution of top predators, seabirds and marine mammals, was determined in the high arctic pack ice on board the icebreaker rv polarstern in july to september 2014. in total, 1,620 transect counts were realised, lasting 30 min each. the five most numerous seabird species represented 74% of the total of 15,150 individuals registered: kittiwake rissa tridactyla, fulmar fulmarus glacialis, puffin fratercula arctica, ross's gull rhodostethia rosea, and little auk alle alle. eight cetac ...201627777810
antidog igg secondary antibody successfully detects igg in a variety of aquatic mammals.serological tests play an important role in the detection of wildlife diseases. however, while there are many commercial assays and reagents available for domestic species, there is a need to develop efficient serological assays for wildlife. in recent years, marine mammals have represented a wildlife group with emerging infectious diseases, such as influenza, brucellosis, and leptospirosis. however, with the exception of disease-agent-specific assays or functional assays, few reports describe t ...201628080908
a colostrum trypsin inhibitor gene expressed in the cape fur seal mammary gland during lactation.the colostrum trypsin inhibitor (cti) gene and transcript were cloned from the cape fur seal mammary gland and cti identified by in silico analysis of the pacific walrus and polar bear genomes (order carnivora), and in marine and terrestrial mammals of the orders cetartiodactyla (yak, whales, camel) and perissodactyla (white rhinoceros). unexpectedly, weddell seal cti was predicted to be a pseudogene. cape fur seal cti was expressed in the mammary gland of a pregnant multiparous seal, but not in ...201626639991
zebra alphaherpesviruses (ehv-1 and ehv-9): genetic diversity, latency and co-infections.alphaherpesviruses are highly prevalent in equine populations and co-infections with more than one of these viruses' strains frequently diagnosed. lytic replication and latency with subsequent reactivation, along with new episodes of disease, can be influenced by genetic diversity generated by spontaneous mutation and recombination. latency enhances virus survival by providing an epidemiological strategy for long-term maintenance of divergent strains in animal populations. the alphaherpesviruses ...201627657113
expanded spectrum of congenital ocular findings in microcephaly with presumed zika infection.to describe the ocular findings of 3 cases of suspected congenital zika viral infection with microcephaly and maculopathy.201627236271
[a case of osteosarcoma in a white polar bear].a male polar bear was caught at the franz josef land at the age of 1 year and then lived in moscow zoo for 6 years. thickening of the distal part of the right hind limb was noted in 1993. destructive changes in the region of epymetaphysis were observed roentgenologically suggesting osteolytic osteosarcoma. the bear was euthanized and, at autopsy, the tumor had 15 cm in diameter and the distal parts of fibula and tibia were completely destroyed. numerous cavities containing blood and necrotic are ...20168579504
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 ...201526552373
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 ...201526220443
[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 ...201526445747
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 ...201524958011
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 ...201525463724
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 ...201524935263
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); ...201526453403
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 ...201526210746
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 ...201525859330
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 ...201526019166
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 ...201525829853
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 ...201526005754
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 ...201524953756
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 ...201526264959
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 ...201526026577
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 ...201525562525
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 ...201525490862
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 ...201526610552
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 ...201526525575
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 ...201525775930
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 ...201526580809
erratum to: a review of infectious agents in polar bears (ursus maritimus) and their long-term ecological relevance. 201526446003
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 ...201526382387
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 ...201526379094
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 ...201526313569
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 ...201526306171
correction: implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming arctic. 201526273835
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 ...201526253644
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 ...201526252623
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 ...201526250829
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 ...201526214910
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 ...201526185248
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 ...201526172596
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 ...201526134828
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 ...201526061693
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 ...201526044932
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 ...201526005914
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 ...201525923717
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 ...201525825130
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 ...201525791679
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 ...201525754352
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 ...201525725300
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.201528360682
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 ...201525682255
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.201525680588
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 ...201525679818
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 ...201525601730
himalayan 'yeti' dna: polar bear or dna degradation? a comment on 'genetic analysis of hair samples attributed to yeti' by sykes et al. (2014). 201525520353
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 ...201525496266
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 ...201525460663
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 ...201525375943
thinking about white bears: fertility issues in young breast cancer survivors. 201525200632
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 ...201525187336
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 ...201524933263
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 ...201525064740
polar bears from space: assessing satellite imagery as a tool to track arctic wildlife.development of efficient techniques for monitoring wildlife is a priority in the arctic, where the impacts of climate change are acute and remoteness and logistical constraints hinder access. we evaluated high resolution satellite imagery as a tool to track the distribution and abundance of polar bears. we examined satellite images of a small island in foxe basin, canada, occupied by a high density of bears during the summer ice-free season. bears were distinguished from other light-colored spot ...201425006979
identifying and managing an adverse food reaction in a polar bear (ursus maritimus) by an elimination diet trial.a 16-yr-old polar bear (ursus maritimus) presented with severe diarrhea shortly following transfer to the north carolina zoological park. multiple diagnostic procedures were performed over several months and the cause of the chronic diarrhea was inconclusive. histologically, colonic mucosal biopsies were consistent with severe chronic eosinophilic and lymphoplasmacytic colitis with no evidence of etiologic agents present. a dietary elimination trial was conducted and an adverse food reaction to ...201425000711
evaluation of polar bear movement patterns in relation to sea ice drift. 201424985513
adult facial growth: applications to aesthetic surgery.reshaping of the face with age is a result of volume change and loss of support. it is not well understood which tissues are involved in this process. recent publications suggest that adult bone growth may have a significant role.201415058547
assessment of dietary intake among inuvialuit in arctic canada using a locally developed quantitative food frequency questionnaire.inuvialuit in arctic canada are experiencing a nutritional and lifestyle transition, characterized by a declining consumption of traditional foods, increased consumption of non-nutrient-dense store-bought foods (nndf), and reduced levels of physical activity with a concurrent rise in chronic diseases. the aim of the present study was to determine dietary intake of inuvialuit adults in the northwest territories, canada, using a culturally specific, validated quantitative food frequency questionna ...201424724772
omental torsion in a captive polar bear (ursus maritimus).this is the first case report of an omental torsion in a polar bear (ursus maritimus). a captive, 23-yr-old, 250-kg, intact female polar bear presented to the university of minnesota veterinary medical center with a 2-day history of lethargy, depression, and vomiting. abdominal ultrasound identified large amounts of hyperechoic free peritoneal fluid. ultrasound-guided abdominocentesis was performed and yielded thick serosanguinous fluid compatible with a hemoabdomen. an exploratory laparotomy re ...201424712179
a retrospective study of end-stage renal disease in captive polar bears (ursus maritimus).this retrospective study summarizes 11 cases of end-stage renal disease (esrd) in captive polar bears (ursus maritimus) from eight zoologic institutions across the united states and canada. ten bears were female, one was male, and the mean age at the time of death was 24 yr old. the most common clinical signs were lethargy, inappetence, and polyuria-polydipsia. biochemical findings included azotemia, anemia, hyperphosphatemia, and isosthenuria. histologic examination commonly showed glomerulonep ...201424712164
validation of adipose lipid content as a body condition index for polar bears.body condition is a key indicator of individual and population health. yet, there is little consensus as to the most appropriate condition index (ci), and most of the currently used cis have not been thoroughly validated and are logistically challenging. adipose samples from large datasets of capture biopsied, remote biopsied, and harvested polar bears were used to validate adipose lipid content as a ci via tests of accuracy, precision, sensitivity, biopsy depth, and storage conditions and compa ...201424634735
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 ...201424534459
the relationship of thought suppression and recent rape to disordered eating in emerging adulthood.this study utilizes a prospective design to examine the interaction of recent rape/attempted rape with individual differences in thought suppression on increases in disordered eating symptoms during late adolescence/emerging adulthood. thought suppression is the attempt to suppress unwanted thoughts. we propose that emerging adult women who have experienced recent rape/attempted rape and tend to use thought suppression as a coping mechanism are at risk for increases in disordered eating. 319 wom ...201424439617
calculation of the interfacial free energy of a binary hard-sphere fluid at a planar hard wall.using molecular-dynamics simulation and gibbs-cahn integration, we calculate the interfacial free energy γ of a binary hard-sphere fluid mixture at a structureless, planar hard wall. the calculation is performed as a function of packing fraction (density) for several values of the diameter ratio α = σ2∕σ1, where σ1 and σ2 are the diameters of the two particle types in the mixture. our results are compared to those obtained from the bulk version of the white bear mark ii (wbii) classical density- ...201424437898
estimating allee dynamics before they can be observed: polar bears as a case study.allee effects are an important component in the population dynamics of numerous species. accounting for these allee effects in population viability analyses generally requires estimates of low-density population growth rates, but such data are unavailable for most species and particularly difficult to obtain for large mammals. here, we present a mechanistic modeling framework that allows estimating the expected low-density growth rates under a mate-finding allee effect before the allee effect oc ...201424427306
two types of impairments in ocd: obsessions, as problems of thought suppression; compulsions, as behavioral-executive impairment.impairments in executive functioning have been identified as an underlying cause of obsessive-compulsive disorder (ocd). obsessive patients attempt to suppress certain unwanted thoughts through a mechanism that wegner referred to as 'chronic thought suppression', whereas compulsive patients are unable to inhibit their rituals. we tested 51 ocd patients using the yale-brown obsessive compulsive scale (y-bocs), the white bear suppression inventory (wbsi) and the dysexecutive questionnaire (dex). e ...201424418048
relationships between cognitive appraisals of adolescents with ocd and their mothers.our aim was to investigate cognitive models of ocd via the influence of mothers' cognitive appraisals on children's cognitions and ocd symptoms.201424387924
physiologically based pharmacokinetic modeling of pops in greenlanders.human exposure to persistent organic pollutants (pops) and the potential health impact in the arctic far from the emission sources have been highlighted in numerous studies. as a supplement to human pop biomonitoring studies, a physiologically based pharmacokinetic (pbpk) model was set up to estimate the fate of pops in greenlandic inuit's liver, blood, muscle and adipose tissue following long-term exposure to traditional greenlandic diet. the pbpk model described metabolism, excretion and pop a ...201424382481
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 ...201424366474
genomic resources notes accepted 1 august 2013-30 september 2013.this article documents the public availability of raw transcriptome sequence data and 63,020 snps for the polar bear (ursus maritimus).201424151970
craving facebook? behavioral addiction to online social networking and its association with emotion regulation deficits.to assess disordered online social networking use via modified diagnostic criteria for substance dependence, and to examine its association with difficulties with emotion regulation and substance use.201425170590
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