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polar and brown bear genomes reveal ancient admixture and demographic footprints of past climate change.polar bears (pbs) are superbly adapted to the extreme arctic environment and have become emblematic of the threat to biodiversity from global climate change. their divergence from the lower-latitude brown bear provides a textbook example of rapid evolution of distinct phenotypes. however, limited mitochondrial and nuclear dna evidence conflicts in the timing of pb origin as well as placement of the species within versus sister to the brown bear lineage. we gathered extensive genomic sequence dat ...201222826254
class of consistent fundamental-measure free energies for hard-sphere mixtures.in fundamental-measure theories the bulk excess free-energy density of a hard-sphere fluid mixture is assumed to depend on the partial number densities {ρ(i)} only through the four scaled-particle-theory variables {ξ(α)}, i.e., φ({ρ(i)})→φ({ξ(α)}). by imposing consistency conditions, it is proven here that such a dependence must necessarily have the form φ({ξ(α)})=-ξ(0)ln(1-ξ(3))+ψ(y)ξ(1)ξ(2)/(1-ξ(3)), where y≡ξ(2)(2)/12πξ(1)(1-ξ(3)) is a scaled variable and ψ(y) is an arbitrary dimensionless sc ...201223214514
using fundamental measure theory to treat the correlation function of the inhomogeneous hard-sphere fluid.we investigate the value of the correlation function of an inhomogeneous hard-sphere fluid at contact. this quantity plays a critical role in statistical associating fluid theory, which is the basis of a number of recently developed classical density functionals. we define two averaged values for the correlation function at contact and derive formulas for each of them from the white bear version of the fundamental measure theory functional, using an assumption of thermodynamic consistency. we te ...201223367925
east greenland and barents sea polar bears (ursus maritimus): adaptive variation between two populations using skull morphometrics as an indicator of environmental and genetic differences.a morphometric study was conducted on four skull traits of 37 male and 18 female adult east greenland polar bears (ursus maritimus) collected 1892-1968, and on 54 male and 44 female adult barents sea polar bears collected 1950-1969. the aim was to compare differences in size and shape of the bear skulls using a multivariate approach, characterizing the variation between the two populations using morphometric traits as an indicator of environmental and genetic differences. mixture analysis testin ...201222804342
endodontic therapy in a polar bear (ursus maritimus). 201222792860
tissue-specific concentrations and patterns of perfluoroalkyl carboxylates and sulfonates in east greenland polar bears.several perfluoroalkyl carboxylates (pfcas) and perfluoroalkyl sulfonates (pfsas) of varying chain length are bioaccumulative in biota. however, wildlife reports have focused on liver and with very little examination of other tissues, and thus there is a limited understanding of their distribution and potential effects in the mammalian body. in the present study, the comparative accumulation of c(6) to c(15) pfcas, c(4), c(6), c(8) and c(10) pfsas, and select precursors were examined in the live ...201223057644
"take me to the water"--community and renewal among aging women: a case study of social interaction and exercise among the "polar bears" of martha's vineyard.this article describes the values and practices of a water exercise group of middle-class, middle-aged and senior female predominantly african american vacationing members of the polar bears of martha's vineyard, massachusetts. it focuses on their holistic approach to health-physical, emotional, and spiritual-and their implementation of this approach through mentoring, play, and the use of certain african american cultural retention practices. it is based on 11 years of summer ethnographic field ...201222757760
longitudinal fecal hormone analysis for monitoring reproductive activity in the female polar bear (ursus maritimus).the objective was to identify suitable enzyme immunoassays to monitor gonadal and placental function in the female polar bear. immunoreactive progesterone, progesterone metabolite (pdg), estrogen, and androgen metabolite (t) concentrations were measured in fecal samples collected over 24 mo from captive female bears (n = 20). whereas fecal extracts produced displacement curves parallel to the standard curve for each respective steroid, t and pdg more accurately reflected reproductive events. con ...201223040062
perfluoroalkyl substances in polar bear mother-cub pairs: a comparative study based on plasma levels from 1998 and 2008.perfluoroalkyl substances (pfass) are protein-binding blood-accumulating contaminants that may have detrimental toxicological effects on the early phases of mammalian development. to enable an evaluation of the potential health risks of pfas exposure for polar bears (ursus maritimus), an exposure assessment was made by examining plasma levels of pfass in polar bear mothers in relation to their suckling cubs-of-the-year (~4 months old). samples were collected at svalbard in 1998 and 2008, and we ...201223010253
influence of carbon and lipid sources on variation of mercury and other trace elements in polar bears (ursus maritimus).in the present study, the authors investigated the influence of carbon and lipid sources on regional differences in liver trace element (as, cd, cu, total hg, mn, pb, rb, se, and zn) concentrations measured in polar bears (ursus maritimus) (n = 121) from 10 alaskan, canadian arctic, and east greenland subpopulations. carbon and lipid sources were assessed using δ(13) c in muscle tissue and fatty acid (fa) profiles in subcutaneous adipose tissue as chemical tracers. a negative relationship betwee ...201222987581
climate's role in polar bear past. 201222679079
respiratory and olfactory turbinal size in canid and arctoid carnivorans.within the nasal cavity of mammals is a complex scaffold of paper-thin bones that function in respiration and olfaction. known as turbinals, the bones greatly enlarge the surface area available for conditioning inspired air, reducing water loss, and improving olfaction. given their functional significance, the relative development of turbinal bones might be expected to differ among species with distinct olfactory, thermoregulatory and/or water conservation requirements. here we explore the surfa ...201223035637
effects of climate warming on polar bears: a review of the evidence.climate warming is causing unidirectional changes to annual patterns of sea ice distribution, structure, and freeze-up. we summarize evidence that documents how loss of sea ice, the primary habitat of polar bears (ursus maritimus), negatively affects their long-term survival. to maintain viable subpopulations, polar bears depend on sea ice as a platform from which to hunt seals for long enough each year to accumulate sufficient energy (fat) to survive periods when seals are unavailable. less tim ...201224501049
level and temporal trend of perfluoroalkyl acids in greenlandic inuit.perfluoroalkyl acids (pfaas) have been detected in human blood, breast milk and umbilical cord blood across the globe. pfaas do accumulate in the marine food chain in arctic regions. in greenland, increasing pfaa concentrations were observed during 1982-2006 in ringed seals and polar bears. however, until now, no data have been reported for pfaas in greenlandic inuit. this study assesses the level and temporal trend of serum pfaas in greenlandic inuit.201222456049
level and temporal trend of perfluoroalkyl acids in greenlandic inuit.perfluoroalkyl acids (pfaas) have been detected in human blood, breast milk and umbilical cord blood across the globe. pfaas do accumulate in the marine food chain in arctic regions. in greenland, increasing pfaa concentrations were observed during 1982-2006 in ringed seals and polar bears. however, until now, no data have been reported for pfaas in greenlandic inuit. this study assesses the level and temporal trend of serum pfaas in greenlandic inuit.201228417759
genetic relationships of extant brown bears (ursus arctos) and polar bears (ursus maritimus).polar bears (ursus maritimus) and brown bears (ursus arctos) are closely related species for which extensive mitochondrial and nuclear phylogenetic comparisons have been made. we used previously published genotype data for 8 microsatellite dna loci from 930 brown bears in 19 populations and 473 polar bears in 16 populations to compare the population genetic relationships of extant populations of the species. genetic distances (nei standard distance = 1.157), the proportion of private alleles (52 ...201223125409
nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage.recent studies have shown that the polar bear matriline (mitochondrial dna) evolved from a brown bear lineage since the late pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle pleis ...201222517859
simultaneous determination of zolazepam and tiletamine in dog plasma by liquid chromatography coupled to a tandem mass spectrometry.a mixture of tiletamine, a dissociative anesthetic, and zolazepam, a minor tranquilizer, has been widely used as an anesthetic or an immobilizing agent in a variety of animal species. however, interestingly, their pharmacokinetic behaviors have been published only in polar bears and pigs. in this study, we introduce a sensitive liquid chromatography/tandem mass spectrometry (lc/ms/ms) method for determining the two drugs in dog plasma. after simple protein precipitation with acetonitrile includi ...201222259017
latitudinal variability in the seroprevalence of antibodies against toxoplasma gondii in non-migrant and arctic migratory geese.toxoplasma gondii is an intracellular coccidian parasite found worldwide and is known to infect virtually all warm-blooded animals. it requires a cat (family felidae) to complete its full life cycle. despite the absence of wild felids on the arctic archipelago of svalbard, t. gondii has been found in resident predators such as the arctic fox and polar bear. it has therefore been suggested that t. gondii may enter this ecosystem via migratory birds. the objective of this study was to identify loc ...201223339847
the significance of the north water polynya to arctic top predators.the north water polynya (~76°n to 79°n and 70°w to 80°w) is known to be an important habitat for several species of marine mammals and sea birds. for millennia, it has provided the basis for subsistence hunting and human presence in the northernmost part of baffin bay. the abundance of air-breathing top predators also represents a potential source of nutrient cycling that maintains primary production. in this study, aerial surveys conducted in 2009 and 2010 were used for the first time to map th ...201223271401
frequency of consumption of foods and beverages by inuvialuit adults in northwest territories, arctic canada.limited data exist regarding nutrient intakes and overall dietary quality in canadian arctic populations. this cross-sectional study determined the frequency of consumption of traditional meats (e.g. caribou, polar bear, seal, char and whale) and non-traditional store-bought foods including non-traditional meats (e.g. beef, pork and chicken), grains, dairy, fruits, vegetables and non-nutrient dense foods (nndfs) (e.g. butter, chocolate, chips, candy and pop) by inuvialuit adults (175 women, mean ...201222475024
age and sex composition of seals killed by polar bears in the eastern beaufort sea.polar bears (ursus maritimus) of the beaufort sea enter hyperphagia in spring and gain fat reserves to survive periods of low prey availability. we collected information on seals killed by polar bears (n=650) and hunting attempts on ringed seal (pusa hispida) lairs (n=1396) observed from a helicopter during polar bear mark-recapture studies in the eastern beaufort sea in spring in 1985-2011. we investigated how temporal shifts in ringed seal reproduction affect kill composition and the intraspec ...201222829949
accumulation of vitamin a in the hepatic stellate cell of arctic top predators.we performed a systematic characterization of the hepatic vitamin a storage in mammals and birds of the svalbard archipelago and greenland. the liver of top predators, including polar bear, arctic fox, bearded seal, and glaucous gull, contained about 10-20 times more vitamin a than the liver of all other arctic animals studied, as well as their genetically related continental top predators. the values are also high compared to normal human and experimental animals like mouse and rat. this massiv ...201222907891
associations between complex ohc mixtures and thyroid and cortisol hormone levels in east greenland polar bears.the multivariate relationship between hair cortisol, whole blood thyroid hormones, and the complex mixtures of organohalogen contaminant (ohc) levels measured in subcutaneous adipose of 23 east greenland polar bears (eight males and 15 females, all sampled between the years 1999 and 2001) was analyzed using projection to latent structure (pls) regression modeling. in the resulting pls model, most important variables with a negative influence on cortisol levels were particularly bde-99, but also ...201222575327
complete genome sequence of equine herpesvirus type 9.equine herpesvirus type 9 (ehv-9), which we isolated from a case of epizootic encephalitis in a herd of thomson's gazelles (gazella thomsoni) in 1993, has been known to cause fatal encephalitis in thomson's gazelle, giraffe, and polar bear in natural infections. our previous report indicated that ehv-9 was similar to the equine pathogen equine herpesvirus type 1 (ehv-1), which mainly causes abortion, respiratory infection, and equine herpesvirus myeloencephalopathy. we determined the genome sequ ...201223166237
sequence analysis of three pigmentation genes in the newfoundland population of canis latrans links the golden retriever mc1r variant to white coat color in coyotes.three genes, mc1r, agouti, and cbd103, interact in a type-switching process that controls much of the pigmentation variation observed in mammals. a deletion in the cbd103 gene is responsible for dominant black color in dogs, while the white-phased black bear ("spirit bear") of british columbia, canada, is the lightest documented color variant caused by a mutation in mc1r. rare all-white animals have recently been discovered in a new northeastern population of the coyote in insular newfoundland a ...201323297074
a novel endogenous betaretrovirus group characterized from polar bears (ursus maritimus) and giant pandas (ailuropoda melanoleuca).transcriptome analysis of polar bears (ursus maritimus) yielded sequences with highest similarity to the human endogenous retrovirus group herv-k(hml-2). further analysis of the polar bear draft genome identified an endogenous betaretrovirus group comprising 26 proviral copies and 231 solo ltrs. molecular dating indicates the group originated before the divergence of bears from a common ancestor but is not present in all carnivores. closely related sequences were identified in the giant panda (a ...201323725819
halogenated phenolic compound determination in plasma and serum by solid phase extraction, dansylation derivatization and liquid chromatography-positive electrospray ionization-tandem quadrupole mass spectrometry.a robust, sensitive and accurate method was developed for the simultaneous determination in plasma and serum of suite a halogenated phenolic compounds (hpcs) for which several are known to persist in the environment and analytically pure standards are available. namely, 14 congeners of hydroxylated polybrominated diphenyl ethers (oh-pbdes), six congeners of hydroxylated polychlorinated biphenyls (oh-pcbs), pentachlorophenol, pentabromophenol and the flame retardant tetrabromobisphenol a (tbbpa). ...201324210890
was the giant short-faced bear a hyper-scavenger? a new approach to the dietary study of ursids using dental microwear textures.dramatic environmental changes associated with global cooling since the late miocene, and the onset of glacial-interglacial cycles in the pleistocene served as a backdrop to the evolutionary radiation of modern bears (family ursidae). these environmental changes likely prompted changes in food availability, and triggered dietary adaptations that served as motive forces in ursid evolution. here, we assess correspondence of dental microwear textures of first and second lower molars with diet in ex ...201324204860
what are the toxicological effects of mercury in arctic biota?this review critically evaluates the available mercury (hg) data in arctic marine biota and the inuit population against toxicity threshold values. in particular marine top predators exhibit concentrations of mercury in their tissues and organs that are believed to exceed thresholds for biological effects. species whose concentrations exceed threshold values include the polar bears (ursus maritimus), beluga whale (delphinapterus leucas), pilot whale (globicephala melas), hooded seal (cystophora ...201323231888
what to eat now? shifts in polar bear diet during the ice-free season in western hudson bay.under current climate trends, spring ice breakup in hudson bay is advancing rapidly, leaving polar bears (ursus maritimus) less time to hunt seals during the spring when they accumulate the majority of their annual fat reserves. for this reason, foods that polar bears consume during the ice-free season may become increasingly important in alleviating nutritional stress from lost seal hunting opportunities. defining how the terrestrial diet might have changed since the onset of rapid climate chan ...201324223286
smallest bitter taste receptor (t2rs) gene repertoire in carnivores.bitter taste reception is presumably associated with dietary selection, preventing animals from ingesting potentially harmful compounds. accordingly, carnivores, who encounter these toxic substances less often, should have fewer genes associated with bitter taste reception compared with herbivores and omnivores. to investigate the genetic basis of bitter taste reception, we confirmed bitter taste receptor (t2r) genes previously found in the genome sequences of two herbivores (cow and horse), two ...201323776004
effects of methylmercury on epigenetic markers in three model species: mink, chicken and yellow perch.we previously reported that methylmercury (mehg) exposure is associated with dna hypomethylation in the brain stem of male polar bears. here, we conveniently use archived tissues obtained from controlled laboratory exposure studies to look for evidence that mehg can disrupt dna methylation across taxa. brain (cerebrum) tissues from mehg-exposed mink (neovison vison), chicken (gallus gallus) and yellow perch (perca flavescens) were analyzed for total hg levels and global dna methylation. tissues ...201323481557
a protein a/g indirect enzyme-linked immunosorbent assay for the detection of anti-brucella antibodies in arctic wildlife.a species-independent indirect enzyme-linked immunosorbent assay (ielisa) based on chimeric protein a/g was established for the detection of anti-brucella antibodies in arctic wildlife species and compared to previously established brucellosis serological tests for hooded seals (cystophora cristata), minke whales (balaenoptera acutorostrata), sei whales (balaenoptera borealis), fin whales (balaenoptera physalus), and polar bears (ursus maritimus), as well as bacteriology results for reindeer and ...201323572454
variation in the response of an arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations.polar bears (ursus maritimus) have experienced substantial changes in the seasonal availability of sea ice habitat in parts of their range, including the beaufort, chukchi, and bering seas. in this study, we compared the body size, condition, and recruitment of polar bears captured in the chukchi-bering seas (cs) between two periods (1986-1994 and 2008-2011) when declines in sea ice habitat occurred. additionally, we compared metrics for the cs population 2008-2011 with those of the adjacent sou ...201323913506
paradoxical effects of thought suppression.in a first experiment, subjects verbalizing the stream of consciousness for a 5-min period were asked to try not to think of a white bear, but to ring a bell in case they did. as indicated both by mentions and by bell rings, they were unable to suppress the thought as instructed. on being asked after this suppression task to think about the white bear for a 5-min period, these subjects showed significantly more tokens of thought about the bear than did subjects who were asked to think about a wh ...20133612492
molecular phylogeography of the brown bear (ursus arctos) in northeastern asia based on analyses of complete mitochondrial dna sequences.to further elucidate the migration history of the brown bears (ursus arctos) on hokkaido island, japan, we analyzed the complete mitochondrial dna (mtdna) sequences of 35 brown bears from hokkaido, the southern kuril islands (etorofu and kunashiri), sakhalin island, and the eurasian continent (continental russia, bulgaria, and tibet), and those of four polar bears. based on these sequences, we reconstructed the maternal phylogeny of the brown bear and estimated divergence times to investigate th ...201323619144
comment on "nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage".based on nuclear and mitochondrial dna, hailer et al. (reports, 20 april 2012, p. 344) suggested early divergence of polar bears from a common ancestor with brown bears and subsequent introgression. our population genetic analysis that traces each of the genealogies in the independent nuclear loci does not support the evolutionary model proposed by the authors.201323539580
could brown bears (ursus arctos) have survived in ireland during the last glacial maximum?brown bears are recorded from ireland during both the late pleistocene and early-mid holocene. although most of the irish landmass was covered by an ice sheet during the last glacial maximum (lgm), irish brown bears are known to have hybridized with polar bears during the late pleistocene, and it is suggested that the irish brown bear population did not become extinct but instead persisted in situ through the lgm in a southwestern ice-free refugium. we use historical population modelling to demo ...201323676655
genomic evidence for island population conversion resolves conflicting theories of polar bear evolution.despite extensive genetic analysis, the evolutionary relationship between polar bears (ursus maritimus) and brown bears (u. arctos) remains unclear. the two most recent comprehensive reports indicate a recent divergence with little subsequent admixture or a much more ancient divergence followed by extensive admixture. at the center of this controversy are the alaskan abc islands brown bears that show evidence of shared ancestry with polar bears. we present an analysis of genome-wide sequence dat ...201323516372
polar bears: the fate of an icon.polar bears are one of the most iconic animals on our planet. worldwide, even people who would never see one are drawn to these charismatic arctic ice hunters. they are the world's largest terrestrial carnivore, and despite being born on land, they spend most of their lives out on the sea ice and are considered a marine mammal. current global studies estimate there are around 20,000 animals in some 19 discrete circumpolar populations. aside from pregnant females denning in the winter months to g ...201324331553
trends of perfluorochemicals in greenland ringed seals and polar bears: indications of shifts to decreasing trends.time-series of perfluorinated alkylated substances (pfass) in east greenland polar bears and east and west greenland ringed seals were updated in order to deduce whether a response to the major reduction in perfluoroalkyl production in the early 2000s had occurred. previous studies had documented an exponential increase of perfluorooctane sulphonate (pfos) in liver tissue from both species. in the present study, pfos was still the far most dominant compound constituting 92% (west greenland ringe ...201324025534
global change effects on the long-term feeding ecology and contaminant exposures of east greenland polar bears.rapid climate changes are occurring in the arctic, with substantial repercussions for arctic ecosystems. it is challenging to assess ecosystem changes in remote polar environments, but one successful approach has entailed monitoring the diets of upper trophic level consumers. quantitative fatty acid signature analysis (qfasa) and fatty acid carbon isotope (δ(13) c-fa) patterns were used to assess diets of east greenland (eg) polar bears (ursus maritimus) (n = 310) over the past three decades. qf ...201323640921
ancestral polymorphisms and sex-biased migration shaped the demographic history of brown bears and polar bears.recent studies have reported discordant gene trees in the evolution of brown bears and polar bears. genealogical histories are different among independent nuclear loci and between biparentally inherited autosomal dna (adna) and matrilineal mitochondrial dna (mtdna). based on multi-locus genomic sequences from adna and mtdna, we inferred the population demography of brown and polar bears and found that brown bears have 6 times (adna) or more than 14 times (mtdna) larger population sizes than pola ...201324236053
a simple and novel method for retrieval of pasteurellaceae from swab samples collected in the field.traditionally it has been difficult or impossible to collect and preserve bacterial samples of especially fastidious bacteria in mixed primary cultures, unless the samples could be transported to a laboratory within approximately 24 h. therefore, a simple novel method for preserving swab samples until bacterial isolation can be completed in the laboratory was developed and evaluated. pasteurellaceae bacteria were used as a representative for fastidious bacteria. a 7.5% glucose serum medium was u ...201323897719
development and initial validation of the white bear suppression inventory (smoking version).thought suppression can produce a paradoxical rebound in unwanted cognition. although interest in the role of suppression in nicotine dependence is growing quickly, a validated measure specifically assessing suppression of smoking-related thoughts does not exist. the present study describes the development of the white bear suppression inventory-smoking version (wbsi-s).201323178321
combined and interactive effects of global climate change and toxicants on populations and communities.increased temperature and other environmental effects of global climate change (gcc) have documented impacts on many species (e.g., polar bears, amphibians, coral reefs) as well as on ecosystem processes and species interactions (e.g., the timing of predator-prey interactions). a challenge for ecotoxicologists is to predict how joint effects of climatic stress and toxicants measured at the individual level (e.g., reduced survival and reproduction) will be manifested at the population level (e.g. ...201323147390
three decades (1983-2010) of contaminant trends in east greenland polar bears (ursus maritimus). part 2: brominated flame retardants.brominated flame retardants were determined in adipose tissues from 294 polar bears (ursus maritimus) sampled in east greenland in 23 of the 28years between 1983 and 2010. significant linear increases were found for sum polybrominated diphenyl ether (σpbde), bde100, bde153, and hexabromocyclododecane (hbcd). average increases of 5.0% per year (range: 2.9-7.6%/year) were found for the subadult polar bears. bde47 and bde99 concentrations did not show a significant linear trend over time, but rathe ...201323137556
three decades (1983-2010) of contaminant trends in east greenland polar bears (ursus maritimus). part 1: legacy organochlorine contaminants.legacy organochlorine contaminants were determined in adipose tissues from 294 polar bears (ursus maritimus) sampled in east greenland in 23 of the 28years between 1983 and 2010. of 19 major legacy contaminants and congeners (σpcb, 4 pcb congeners (cb153, 180, 170/190), σddt, p,p'-dde, p,p' -ddd and p,p'-ddt, α- and β-hexachlorocyclohexane (hch), hcb, octachlorostyrene, dieldrin, oxychlordane, cis- and trans-chlordane, cis- and trans-nonachlor, heptachlor epoxide and bb-153), 18 showed statistic ...201323078749
a classical density-functional theory for describing water interfaces.we develop a classical density functional for water which combines the white bear fundamental-measure theory (fmt) functional for the hard sphere fluid with attractive interactions based on the statistical associating fluid theory variable range (saft-vr). this functional reproduces the properties of water at both long and short length scales over a wide range of temperatures and is computationally efficient, comparable to the cost of fmt itself. we demonstrate our functional by applying it to s ...201323320706
dietary composition and spatial patterns of polar bear foraging on land in western hudson bay.flexible foraging strategies, such as prey switching, omnivory and food mixing, are key to surviving in a labile and changing environment. polar bears (ursus maritimus) in western hudson bay are versatile predators that use all of these strategies as they seasonally exploit resources across trophic levels. climate warming is reducing availability of their ice habitat, especially in spring when polar bears gain most of their annual fat reserves by consuming seal pups before coming ashore in summe ...201324359342
recovery trends in marine mammal populations.marine mammals have greatly benefitted from a shift from resource exploitation towards conservation. often lauded as symbols of conservation success, some marine mammal populations have shown remarkable recoveries after severe depletions. others have remained at low abundance levels, continued to decline, or become extinct or extirpated. here we provide a quantitative assessment of (1) publicly available population-level abundance data for marine mammals worldwide, (2) abundance trends and recov ...201324205025
characterization of blood lipoproteins and validation of cholesterol and triacylglycerol assays for free-ranging polar bears (ursus maritimus).blood triacylglycerol (tg) and lipoproteins are important variables for evaluating nutritional status of wildlife, but measurements are often expensive and difficult. performance of a small, portable blood analyzer intended for human medical diagnostics was evaluated in measuring these variables in plasma and serum from free-ranging polar bears (ursus maritimus), which are experiencing nutritional stress related to sea ice loss. the analyzer accurately tracked changes in concentration of total c ...201323632660
beyond the mean: sensitivities of the variance of population growth.populations in variable environments are described by both a mean growth rate and a variance of stochastic population growth. increasing variance will increase the width of confidence bounds around estimates of population size, growth, probability of and time to quasi-extinction. however, traditional sensitivity analyses of stochastic matrix models only consider the sensitivity of the mean growth rate. we derive an exact method for calculating the sensitivity of the variance in population growth ...201326635948
allocating attention to distractor locations is based on top-down expectations.failures of selective attention may be explained by the attentional white bear (awb) hypothesis maintaining that prior knowledge of distractor location causes attentional allocation to it. the awb is demonstrated by embedding infrequent trials of two simultaneous dots among flanker trials. the dot at the expected distractor location is perceived as appearing before the dot at the expected empty location, indicating attentional allocation to expected distractor locations. a major requirement of t ...201323425450
direct correlation function from the consistent fundamental-measure free energies for hard-sphere mixtures.in a recent paper [phys. rev. e 86, 040102(r) (2012)], santos presented a self-consistency condition that can be used to limit the possible forms of fundamental measure theory. here, the direct correlation function, resulting from the santos functional, is derived, and it is found to be very close to the result of the white bear density functional, except near the origin where it diverges.201323410469
xenoestrogenic and dioxin-like activity in blood of east greenland polar bears (ursus maritimus).the aims of the project were to (i) extract the lipophilic persistent organic pollutants (pops) from the blood of 99 east greenland polar bears and assess the combined mixture effect on the estrogen receptor (er) and the aryl hydrocarbon receptor (ahr) mediated transactivity; (ii) to evaluate whether the receptor transactivities were associated with selected pop markers, and (iii) compare the receptor transactivities in polar bears with earlier studies on greenlandic inuit. lipophilic pops were ...201323648332
linear and branched perfluorooctane sulfonate (pfos) isomer patterns differ among several tissues and blood of polar bears.perfluorooctane sulfonate (pfos) is a globally distributed persistent organic pollutant that has been found to bioaccumulate and biomagnify in aquatic food webs. although principally in its linear isomeric configuration, 21-35% of the pfos manufactured via electrochemical fluorination is produced as a branched structural isomer. pfos isomer patterns were investigated in multiple tissues of polar bears (ursus maritimus) from east greenland. the liver (n = 9), blood (n = 19), brain (n = 16), muscl ...201323920361
crescentic glomerulonephritis in a polar bear (ursus maritimus).spontaneous crescentic glomerulonephritis (crgn) in animals has only been reported in dog and sheep. we report the pathological features of crgn in a 17-year-old male polar bear that died due to renal failure. histologically, the lesions were characterized by fibrocellular crescents, adhesion between bowman's capsule and the glomerular capillary tuft and an increase in the mesangial matrix in glomeruli. the proliferating cells in the crescent were partly immunopositive for cytokeratin and intens ...201323856758
effect-directed analysis to explore the polar bear exposome: identification of thyroid hormone disrupting compounds in plasma.compounds with transthyretin (ttr)-binding potency in the blood plasma of polar bear cubs were identified with effect-directed analysis (eda). this approach contributes to the understanding of the thyroid disrupting exposome of polar bears. the selection of these samples for in-depth eda was based on the difference between the observed ttr-binding potency on the one hand and the calculated potency (based on known concentrations of ttr-binding compounds and their relative potencies) on the other. ...201323763488
global warming triggers the loss of a key arctic refugium.we document the rapid transformation of one of the earth's last remaining arctic refugia, a change that is being driven by global warming. in stark contrast to the amplified warming observed throughout much of the arctic, the hudson bay lowlands (hbl) of subarctic canada has maintained cool temperatures, largely due to the counteracting effects of persistent sea ice. however, since the mid-1990s, climate of the hbl has passed a tipping point, the pace and magnitude of which is exceptional even b ...201324107529
extensive sampling of polar bears (ursus maritimus) in the northwest passage (canadian arctic archipelago) reveals population differentiation across multiple spatial and temporal scales.as global warming accelerates the melting of arctic sea ice, polar bears (ursus maritimus) must adapt to a rapidly changing landscape. this process will necessarily alter the species distribution together with population dynamics and structure. detailed knowledge of these changes is crucial to delineating conservation priorities. here, we sampled 361 polar bears from across the center of the canadian arctic archipelago spanning the gulf of boothia (gb) and m'clintock channel (mc). we use dna mic ...201324102001
future sea ice conditions in western hudson bay and consequences for polar bears in the 21st century.the primary habitat of polar bears is sea ice, but in western hudson bay (wh), the seasonal ice cycle forces polar bears ashore each summer. survival of bears on land in wh is correlated with breakup and the ice-free season length, and studies suggest that exceeding thresholds in these variables will lead to large declines in the wh population. to estimate when anthropogenic warming may have progressed sufficiently to threaten the persistence of polar bears in wh, we predict changes in the ice c ...201323716301
response to comment on "nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage".nakagome et al. reanalyzed some of our data and assert that we cannot refute the mitochondrial dna-based scenario for polar bear evolution. their single-locus test statistic is strongly affected by introgression and incomplete lineage sorting, whereas our multilocus approaches are better suited to recover the true species relationships. indeed, our sister-lineage model receives high support in a bayesian model comparison.201323539581
simulating polar bear energetics during a seasonal fast using a mechanistic model.in this study we tested the ability of a mechanistic model (niche mapper™) to accurately model adult, non-denning polar bear (ursus maritimus) energetics while fasting during the ice-free season in the western hudson bay. the model uses a steady state heat balance approach, which calculates the metabolic rate that will allow an animal to maintain its core temperature in its particular microclimate conditions. predicted weight loss for a 120 day fast typical of the 1990s was comparable to empiric ...201324019883
the polar bear in the room: diseases of poverty in the arctic.in the face of global warming, budgetary austerity and impoverished arctic residents, the nations of the circumpolar region are presented with a number of difficult choices regarding the provision of health care to the far-flung and isolated regions of their northernmost provinces. complicating that picture is the reality of neglected tropical diseases in areas far from their perceived normal equatorial range as well as endemic food-borne diseases, including protozoan and helminth parasites, res ...201323984296
transthyretin-binding activity of contaminants in blood from polar bear (ursus maritimus) cubs.we determined the transthyretin (ttr)-binding activity of blood-accumulating contaminants in blood plasma samples of approximately 4-months-old polar bear (ursus maritimus) cubs from svalbard sampled in 1998 and 2008. the ttr-binding activity was measured as thyroxine (t4)-like equivalents (t4-eqmeas). our findings show that the ttr-binding activity related to contaminant levels was significantly lower (45%) in 2008 than in 1998 (mean ± standard error of mean: 1998, 2265 ± 231 nm; 2008, 1258 ± 1 ...201323551254
migration phenology and seasonal fidelity of an arctic marine predator in relation to sea ice dynamics.understanding how seasonal environmental conditions affect the timing and distribution of synchronized animal movement patterns is a central issue in animal ecology. migration, a behavioural adaptation to seasonal environmental fluctuations, is a fundamental part of the life history of numerous species. however, global climate change can alter the spatiotemporal distribution of resources and thus affect the seasonal movement patterns of migratory animals. we examined sea ice dynamics relative to ...201323510081
factor structure and clinical correlates of the food thought suppression inventory within treatment seeking obese women with binge eating disorder.prior research on the relations among eating behaviors and thought suppression is limited to a measure of general thought suppression, the white bear suppression inventory. to address this limitation, researchers recently validated the food thought suppression inventory (ftsi). analyses using this measure suggest that food thought suppression is distinct from and is more predictive of eating disorder psychopathology than is general thought suppression. the ftsi, however, has not yet been validat ...201323265399
females roam while males patrol: divergence in breeding season movements of pack-ice polar bears (ursus maritimus).intraspecific differences in movement behaviour reflect different tactics used by individuals or sexes to favour strategies that maximize fitness. we report movement data collected from n = 23 adult male polar bears with novel ear-attached transmitters in two separate pack ice subpopulations over five breeding seasons. we compared movements with n = 26 concurrently tagged adult females, and analysed velocities, movement tortuosity, range sizes and habitat selection with respect to sex, reproduct ...201323222446
coping in long-term survivors of childhood cancer: relations to psychological distress.the goal of this study was to describe coping strategies and their associations with psychological distress in young adult survivors of childhood cancer.201322461240
effects of selective serotonin reuptake inhibitors on thought-action fusion, metacognitions, and thought suppression in obsessive-compulsive disorder.we aimed to assess whether cognitive processes change over time in patients with obsessive-compulsive disorder (ocd) receiving selective serotonin reuptake inhibitors without cognitive behavioral therapy and to investigate the factors associated with probable cognitive changes.201321109243
brain region distribution and patterns of bioaccumulative perfluoroalkyl carboxylates and sulfonates in east greenland polar bears (ursus maritimus).the present study investigated the comparative accumulation of perfluoroalkyl acids (pfaas) in eight brain regions of polar bears (ursus maritimus, n = 19) collected in 2006 from scoresby sound, east greenland. the pfaas studied were perfluoroalkyl carboxylates (pfcas, c(6) -c(15) chain lengths) and sulfonates (c(4) , c(6) , c(8) , and c(10) chain lengths) as well as selected precursors including perfluorooctane sulfonamide. on a wet-weight basis, blood-brain barrier transport of pfaas occurred ...201323280712
effectiveness of association splitting in reducing unwanted intrusive thoughts in a nonclinical sample.association splitting (as) is a novel cognitive technique, which has shown some promise for the reduction of obsessive thoughts in patients with obsessive-compulsive disorder (ocd). its effect on unwanted intrusive thoughts (uits) in the general population is yet unknown.201322874829
glucuronidation in the polar bear (ursus maritimus).polar bears bioaccumulate lipophilic pollutants, including polychlorinated biphenyls (pcbs), into their bodies from their exclusive diet of marine organisms. hydroxylated pcb metabolites (oh-pcbs) have been found in plasma, presumably due to cyp-dependent biotransformation of pcbs in liver. little is known about the phase 2 metabolism of hydroxylated xenobiotics in polar bears. the objective of this study was to examine udp-glucuronosyltransferase (ugt) activity with oh-pcbs and a hydroxylated p ...201315178068
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
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
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
field metabolic rate and pcb adipose tissue deposition efficiency in east greenland polar bears derived from contaminant monitoring data.climate change will increasingly affect the natural habitat and diet of polar bears (ursus maritimus). understanding the energetic needs of polar bears is therefore important. we developed a theoretical method for estimating polar bear food consumption based on using the highly recalcitrant polychlorinated biphenyl (pcb) congener, 2,2',4,4',55-hexacb (cb153) in bear adipose tissue as an indicator of food intake. by comparing the cb153 tissue concentrations in wild polar bears with estimates from ...201425101837
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
projected polar bear sea ice habitat in the canadian arctic archipelago.sea ice across the arctic is declining and altering physical characteristics of marine ecosystems. polar bears (ursus maritimus) have been identified as vulnerable to changes in sea ice conditions. we use sea ice projections for the canadian arctic archipelago from 2006 - 2100 to gain insight into the conservation challenges for polar bears with respect to habitat loss using metrics developed from polar bear energetics modeling.201425426720
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
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
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
ovulation induction and artificial insemination of a captive polar bear (ursus maritimus) using fresh semen.in 2008, polar bears were listed as a species threatened with extinction by the u.s. endangered species act. unfortunately, reproductive success has been poor despite breeding recommendations for almost every reproductively viable bear by the species survival plan. assisted reproductive technologies could complement breeding efforts by overcoming the challenges of behavioral incompatibilities and deficiencies, facilitating genetic management and increasing cub production. the goal of this study ...201425314835
[possible sources of trichinella infection in the indigenous population of chukotka].statistical methods confirmed that the dietary intake of traditionally made meat from marine mammals and polar bear could cause trichinella infection in the residents of the communities of the chukotka peninsula.201425286544
personal prayer counteracts self-control depletion.praying over longer time spans can foster self-control. less is known about the immediate, short-term consequences of praying. here we investigated the possibility that praying may counteract self-control depletion. participants suppressed or did not suppress thoughts about a white bear before engaging in a brief period of either personal prayer or free thought. then, all participants completed a stroop task. as expected, thought suppression led to poorer stroop performance in the free thought, ...201425277947
bioinspired materials: from low to high dimensional structure.the surprising properties of biomaterials are the results of billions of years of evolution. generally, biomaterials are assembled under mild conditions with very limited supply of constituents available for living organism, and their amazing properties largely result from the sophisticated hierarchical structures. following the biomimetic principles to prepare manmade materials has drawn great research interests in materials science and engineering. in this review, we summarize the recent progr ...201425212698
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
characterization of a pancreatic islet cell tumor in a polar bear (ursus maritimus).herein, we report a 25-year-old male polar bear suffering from a pancreatic islet cell tumor. the aim of this report is to present a case of this rare tumor in a captive polar bear. the implication of potential risk factors such as high carbohydrate diet or the presence of amyloid fibril deposits was assessed. necropsy examination revealed several other changes, including nodules observed in the liver, spleen, pancreas, intestine, and thyroid glands that were submitted for histopathologic analys ...201425273481
in vivo and in vitro changes in neurochemical parameters related to mercury concentrations from specific brain regions of polar bears (ursus maritimus).mercury (hg) has been detected in polar bear brain tissue, but its biological effects are not well known. relationships between hg concentrations and neurochemical enzyme activities and receptor binding were assessed in the cerebellum, frontal lobes, and occipital lobes of 24 polar bears collected from nunavik (northern quebec), canada. the concentration-response relationship was further studied with in vitro experiments using pooled brain homogenate of 12 randomly chosen bears. in environmental ...201425264143
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
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
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