| assessing polar bear (ursus maritimus) population structure in the hudson bay region using snps. | defining subpopulations using genetics has traditionally used data from microsatellite markers to investigate population structure; however, single-nucleotide polymorphisms (snps) have emerged as a tool for detection of fine-scale structure. in hudson bay, canada, three polar bear (ursus maritimus) subpopulations (foxe basin (fb), southern hudson bay (sh), and western hudson bay (wh)) have been delineated based on mark-recapture studies, radiotelemetry and satellite telemetry, return of marked a ... | 2016 | 28031799 |
| 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 ... | 2016 | 27928000 |
| 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 ... | 2016 | 27903868 |
| sea ice-associated decline in body condition leads to increased concentrations of lipophilic pollutants in polar bears (ursus maritimus) from svalbard, norway. | global climate changes are magnified in the arctic and are having an especially dramatic effect on the spatial and temporal distribution and the thickness traits of sea ice. decline of arctic sea ice may lead to qualitative and/or quantitative changes in diet and reduced body condition (i.e. adipose tissue stores) of ice-associated apex predators such as polar bears (ursus maritimus). this may further affect their tissue concentrations of lipophilic pollutants. we determined how variations in ad ... | 2017 | 27794227 |
| per- and polyfluoroalkyl substances (pfass) - new endocrine disruptors in polar bears (ursus maritimus)? | per- and polyfluoroalkyl substances (pfass) are emerging in the arctic and accumulate in brain tissues of east greenland (eg) polar bears. in vitro studies have shown that pfass might possess endocrine disrupting abilities and therefore the present study was conducted to investigate potential pfas induced alterations in brain steroid concentrations. the concentrations of eleven steroid hormones were determined in eight brain regions from ten eg polar bears. pregnenolone (pre), the dominant proge ... | 2016 | 27692342 |
| costs of locomotion in polar bears: when do the costs outweigh the benefits of chasing down terrestrial prey? | trade-offs between locomotory costs and foraging gains are key elements in determining constraints on predator-prey interactions. one intriguing example involves polar bears pursuing snow geese on land. as climate change forces polar bears to spend more time ashore, they may need to expend more energy to obtain land-based food. given that polar bears are inefficient at terrestrial locomotion, any extra energy expended to pursue prey could negatively impact survival. however, polar bears have bee ... | 2016 | 27757238 |
| circumpolar contaminant concentrations in polar bears (ursus maritimus) and potential population-level effects. | polar bears (ursus maritimus) currently receive much attention in the context of global climate change. however, there are other stressors that might threaten the viability of polar bear populations as well, such as exposure to anthropogenic pollutants. lipophilic organic compounds bio-accumulate and bio-magnify in the food chain, leading to high concentrations at the level of top-predators. in arctic wildlife, including the polar bear, various adverse health effects have been related to interna ... | 2016 | 27450999 |
| demography of an apex predator at the edge of its range: impacts of changing sea ice on polar bears in hudson bay. | changes in the abundance and distribution of wildlife populations are common consequences of historic and contemporary climate change. some arctic marine mammals, such as the polar bear (ursus maritimus), may be particularly vulnerable to such changes due to the loss of arctic sea ice. we evaluated the impacts of environmental variation on demographic rates for the western hudson bay (wh), polar bear subpopulation from 1984 to 2011 using live-recapture and dead-recovery data in a bayesian implem ... | 2016 | 27755745 |
| mass loss rates of fasting polar bears. | polar bears (ursus maritimus) have adapted to an annual cyclic regime of feeding and fasting, which is extreme in seasonal sea ice regions of the arctic. as a consequence of climate change, sea ice breakup has become earlier and the duration of the open-water period through which polar bears must rely on fat reserves has increased. to date, there is limited empirical data with which to evaluate the potential energetic capacity of polar bears to withstand longer fasts. we measured the incoming an ... | 2017 | 27617359 |
| environmental chemicals modulate polar bear (ursus maritimus) peroxisome proliferator-activated receptor gamma (pparg) and adipogenesis in vitro. | we studied interactions between polar bear peroxisome proliferator-activated receptor gamma (pbpparg) and selected compounds using a luciferase reporter assay and predictions through molecular docking. furthermore, we studied adipogenesis by liver and adipose tissue extracts from a polar bear and three synthetic mixtures of contaminants in murine 3t3-l1 preadipocytes and polar bear adipose tissue-derived stem cells (pbascs). pcb153 and p,p'-dde antagonized pbpparg, although their predicted recep ... | 2016 | 27602593 |
| habitat-mediated timing of migration in polar bears: an individual perspective. | migration phenology is largely determined by how animals respond to seasonal changes in environmental conditions. our perception of the relationship between migratory behavior and environmental cues can vary depending on the spatial scale at which these interactions are measured. understanding the behavioral mechanisms behind population-scale movements requires knowledge of how individuals respond to local cues. we show how time-to-event models can be used to predict what factors are associated ... | 2016 | 27547331 |
| invariant polar bear habitat selection during a period of sea ice loss. | climate change is expected to alter many species' habitat. a species' ability to adjust to these changes is partially determined by their ability to adjust habitat selection preferences to new environmental conditions. sea ice loss has forced polar bears (ursus maritimus) to spend longer periods annually over less productive waters, which may be a primary driver of population declines. a negative population response to greater time spent over less productive water implies, however, that prey are ... | 2016 | 27534959 |
| dental and temporomandibular joint pathology of the polar bear (ursus maritimus). | museum specimens (maxillae and/or mandibles) from 317 polar bears (ursus maritimus) were examined macroscopically according to predefined criteria and 249 specimens were included in this study. the specimens were acquired between 1906 and 2011. there were 126 specimens (50.6%) from male animals, 93 (37.3%) from female animals and 30 (12.1%) from animals of unknown sex. the ages of the animals ranged from neonate to adult, with 125 adults (50.2%) and 124 young adults (49.8%) included and neonates ... | 2017 | 27481648 |
| a cluster of three cases of trichinellosis linked to bear meat consumption in the arctic. | we report here three cases of trichinellosis due to polar bear meat consumption in east greenland. in the past 20 years, 31 cases of trichinellosis have been reported in french travellers to the arctic (north quebec, nunavut and greenland) who consumed undercooked meat from black, brown, or polar bears. if local communities are increasingly becoming aware of the risk of trichinellosis, travellers visiting regions where bear meat is consumed should be informed of the risk of eating raw or non-hea ... | 2016 | 27296583 |
| concentrations and patterns of hydroxylated polybrominated diphenyl ethers and polychlorinated biphenyls in arctic foxes (vulpes lagopus) from svalbard. | concentrations and patterns of hydroxylated (oh) polybrominated diphenyl ethers (pbdes) and polychlorinated biphenyls (pcbs) were investigated in liver from arctic foxes (vulpes lagopus) sampled from svalbard 1997-2011 (n = 100). the most important oh-pbde in the arctic foxes was 6-oh-bde47 detected in 24% of the samples. relationships between 6-oh-bde47, δ(13)c and bde47 suggest that 6-oh-bde47 residues in arctic foxes are related to marine dietary input, while the relative importance of the me ... | 2016 | 27267742 |
| the relationship between clinical characteristics, metacognitive appraisals, and cognitive insight in patients with obsessive-compulsive disorder. | cognitive insight, a recently developed insight measure, refers to metacognitive processes of the re-evaluation and correction of distorted beliefs and misinterpretations. however, to the best of the authors' knowledge, no study has specifically examined cognitive insight, demographics, psychopathological variables, and distorted beliefs in ocd. | 2016 | 27249043 |
| state-space models' dirty little secrets: even simple linear gaussian models can have estimation problems. | state-space models (ssms) are increasingly used in ecology to model time-series such as animal movement paths and population dynamics. this type of hierarchical model is often structured to account for two levels of variability: biological stochasticity and measurement error. ssms are flexible. they can model linear and nonlinear processes using a variety of statistical distributions. recent ecological ssms are often complex, with a large number of parameters to estimate. through a simulation st ... | 2016 | 27220686 |
| geographical area and life history traits influence diet in an arctic marine predator. | global changes are thought to affect most arctic species, yet some populations are more at risk. today, the barents sea ecoregion is suffering the strongest sea ice retreat ever measured; and these changes are suspected to modify food access and thus diet of several species. biochemical diet tracers enable investigation of diet in species such as polar bears (ursus maritimus). we examined individual diet variation of female polar bears in svalbard, norway, and related it to year, season (spring ... | 2016 | 27196700 |
| hair mercury concentrations in western hudson bay polar bear family groups. | methylmercury is one of the more toxic forms of mercury (hg), the biomagnification of which is prevalent in the arctic where apex predators such as polar bears (ursus maritimus) can carry high loads. the maternal transfer of contaminants to offspring is a concern, as offspring may be particularly sensitive to the effects of environmental pollutants during early development. however, few studies of polar bears report on hg in dependent young. we examined hair total hg (thg) concentrations in 24 p ... | 2016 | 27095340 |
| demographic and traditional knowledge perspectives on the current status of canadian polar bear subpopulations. | subpopulation growth rates and the probability of decline at current harvest levels were determined for 13 subpopulations of polar bears (ursus maritimus) that are within or shared with canada based on mark-recapture estimates of population numbers and vital rates, and harvest statistics using population viability analyses (pva). aboriginal traditional ecological knowledge (tek) on subpopulation trend agreed with the seven stable/increasing results and one of the declining results, but disagreed ... | 2016 | 27069588 |
| involuntary symbol manipulation (pig latin) from external control: implications for thought suppression. | in ironic processing, one is more likely to think about something (e.g., white bears) when instructed to not think about that thing. entry into consciousness of such content may be automatic, reflecting the 'encapsulated' nature of the generation of conscious contents. based on this research, the reflexive imagery task (rit) reveals that, following the activation of action sets, conscious contents can arise involuntarily and systematically in response to external stimuli. in the most basic versi ... | 2016 | 27043254 |
| circumpolar genetic structure and recent gene flow of polar bears: a reanalysis. | recently, an extensive study of 2,748 polar bears (ursus maritimus) from across their circumpolar range was published in plos one, which used microsatellites and mitochondrial haplotypes to apparently show altered population structure and a dramatic change in directional gene flow towards the canadian archipelago-an area believed to be a future refugium for polar bears as their southernmost habitats decline under climate change. although this study represents a major international collaborative ... | 2016 | 26974333 |
| a novel method for analysing key corticosteroids in polar bear (ursus maritimus) hair using liquid chromatography tandem mass spectrometry. | this paper presents the development and evaluation of a methodology for extraction, clean-up and analysis of three key corticosteroids (aldosterone, cortisol and corticosterone) in polar bear hair. such a methodology can be used to monitor stress biomarkers in polar bears and may provide as a useful tool for long-term and retrospective information. we developed a combined pressurized liquid extraction (ple)-solid phase extraction (spe) procedure for corticosteroid extraction and clean-up followe ... | 2016 | 26945133 |
| taming the white bear: initial costs and eventual benefits of distractor inhibition. | previous research indicates that prior information about a target feature, such as its color, can speed search. can search also be speeded by knowing what a target willnotlook like? in the two experiments reported here, participants searched for target letters. prior to viewing search displays, participants were prompted either with the color in which one or more nontarget letters would appear (ignore trials) or with no information about the search display (neutral trials). critically, when part ... | 2016 | 26893292 |
| distinct mechanisms for distractor suppression and target facilitation. | it is well established that preparatory attention improves processing of task-relevant stimuli. although it is often more important to ignore task-irrelevant stimuli, comparatively little is known about preparatory attentional mechanisms for inhibiting expected distractions. here, we establish that distractor inhibition is not under the same top-down control as target facilitation. using a variant of the posner paradigm, participants were cued to either the location of a target stimulus, the loc ... | 2016 | 26865606 |
| 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 ... | 2016 | 26745384 |
| immunotoxic effects of environmental pollutants in marine mammals. | due to their marine ecology and life-history, marine mammals accumulate some of the highest levels of environmental contaminants of all wildlife. given the increasing prevalence and severity of diseases in marine wildlife, it is imperative to understand how pollutants affect the immune system and consequently disease susceptibility. advancements and adaptations of analytical techniques have facilitated marine mammal immunotoxicology research. field studies, captive-feeding experiments and in vit ... | 2016 | 26590481 |
| increased land use by chukchi sea polar bears in relation to changing sea ice conditions. | recent observations suggest that polar bears (ursus maritimus) are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. we used location data from female polar bears fit with satellite radio collars to compare land use patterns in the chukchi sea between two periods (1986-1995 and 2008-2013) when substantial summer sea-ice loss occurred. in both ... | 2015 | 26580809 |
| erratum to: a review of infectious agents in polar bears (ursus maritimus) and their long-term ecological relevance. | | 2015 | 26446003 |
| modeling diffusion in colloidal suspensions by dynamical density functional theory using fundamental measure theory of hard spheres. | we study the dynamics of colloidal suspensions of hard spheres that are subject to brownian motion in the overdamped limit. we obtain the time evolution of the self- and distinct parts of the van hove function by means of dynamical density functional theory. the free-energy model for the hard-sphere fluid that we use is the very accurate white bear ii version of rosenfeld's fundamental measure theory. however, in order to remove interactions within the self-part of the van hove function, a nontr ... | 2015 | 26382387 |
| elevated accumulation of parabens and their metabolites in marine mammals from the united states coastal waters. | the widespread exposure of humans to parabens present in personal care products is well-known. nevertheless, little is known about the accumulation of parabens in marine organisms. in this study, six parabens and four common metabolites of parabens were measured in 121 tissue samples from eight species of marine mammals collected along the coastal waters of florida, california, washington, and alaska. methyl paraben (mep) was the predominant compound found in the majority of the marine mammal ti ... | 2015 | 26379094 |
| anti-nmda receptor encephalitis in the polar bear (ursus maritimus) knut. | knut the polar bear of the berlin zoological garden drowned in 2011 following seizures and was diagnosed as having suffered encephalitis of unknown etiology after exhaustive pathogen screening. using the diagnostic criteria applied to human patients, we demonstrate that knut's encephalitis is almost identical to anti-nmda receptor encephalitis which is a severe autoimmune disease representing the most common non-infectious encephalitis in humans. high concentrations of antibodies specific agains ... | 2015 | 26313569 |
| population substructure and space use of foxe basin polar bears. | climate change has been identified as a major driver of habitat change, particularly for sea ice-dependent species such as the polar bear (ursus maritimus). population structure and space use of polar bears have been challenging to quantify because of their circumpolar distribution and tendency to range over large areas. knowledge of movement patterns, home range, and habitat is needed for conservation and management. this is the first study to examine the spatial ecology of polar bears in the f ... | 2015 | 26306171 |
| correction: implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming arctic. | | 2015 | 26273835 |
| web-based acceptance and commitment therapy for depressive symptoms with minimal support: a randomized controlled trial. | low-intensity interventions for people suffering from depressive symptoms are highly desirable. the aim of the present study was to investigate the outcomes of a web-based acceptance and commitment therapy (act)-based intervention without face-to-face contact for people suffering from depressive symptoms. participants (n = 39) with depressive symptoms were randomly assigned to an internet-delivered acceptance and commitment therapy (iact) intervention or a waiting list control condition (wlc). p ... | 2015 | 26253644 |
| polar bear mother-offspring interactions in maternity dens in captivity. | two female polar bears at dierenrijk zoo in the netherlands were monitored at their maternity den one day before the birth of their cubs and three days postpartum. each bear was monitored for 96 hr to document behaviour and vocalisations. the goal was to obtain insight into the differences between the mother that lost her litter and the other that successfully reared her cubs. six groups of cub vocalisations were identified: comfort, discomfort, distress, nursing attempts, nursing, and no vocali ... | 2015 | 26252623 |
| genetic signatures of adaptation revealed from transcriptome sequencing of arctic and red foxes. | the genus vulpes (true foxes) comprises numerous species that inhabit a wide range of habitats and climatic conditions, including one species, the arctic fox (vulpes lagopus) which is adapted to the arctic region. a close relative to the arctic fox, the red fox (vulpes vulpes), occurs in subarctic to subtropical habitats. to study the genetic basis of their adaptations to different environments, transcriptome sequences from two arctic foxes and one red fox individual were generated and analyzed ... | 2015 | 26250829 |
| polar bear population dynamics in the southern beaufort sea during a period of sea ice decline. | in the southern beaufort sea of the united states and canada, prior investigations have linked declines in summer sea ice to reduced physical condition, growth, and survival of polar bears (ursus maritimus). combined with projections of population decline due to continued climate warming and the ensuing loss of sea ice habitat, those findings contributed to the 2008 decision to list the species as threatened under the u.s. endangered species act. here, we used mark-recapture models to investigat ... | 2015 | 26214910 |
| animal physiology. summer declines in activity and body temperature offer polar bears limited energy savings. | polar bears (ursus maritimus) summer on the sea ice or, where it melts, on shore. although the physiology of "ice" bears in summer is unknown, "shore" bears purportedly minimize energy losses by entering a hibernation-like state when deprived of food. such a strategy could partially compensate for the loss of on-ice foraging opportunities caused by climate change. however, here we report gradual, moderate declines in activity and body temperature of both shore and ice bears in summer, resembling ... | 2015 | 26185248 |
| polyhalogenated compounds (pcbs, chlordanes, hcb and bfrs) in four polar bears (ursus maritimus) that swam malnourished from east greenland to iceland. | levels of organohalogen compounds (pcbs, chlordane, pbb 153, pbdes, hcb) were determined in adipose tissue, liver, kidney and muscle of four polar bears which swam and/or drifted to iceland in extremely malnourished condition. since the colonization in the 9th century polar bears have been repeatedly observed in iceland. however, in recent years three of the animals have clearly left their natural habitat in poor condition in may or june, i.e. at the end of the major feeding season. the fourth b ... | 2015 | 26172596 |
| pros and cons of methylation-based enrichment methods for ancient dna. | the recent discovery that dna methylation survives in fossil material provides an opportunity for novel molecular approaches in palaeogenomics. here, we apply to ancient dna extracts the probe-independent methylated binding domains (mbd)-based enrichment method, which targets dna molecules containing methylated cpgs. using remains of a palaeo-eskimo saqqaq individual, woolly mammoths, polar bears and two equine species, we confirm that dna methylation survives in a variety of tissues, environmen ... | 2015 | 26134828 |
| the energetic value of land-based foods in western hudson bay and their potential to alleviate energy deficits of starving adult male polar bears. | climate change is predicted to expand the ice-free season in western hudson bay and when it grows to 180 days, 28-48% of adult male polar bears are projected to starve unless nutritional deficits can be offset by foods consumed on land. we updated a dynamic energy budget model developed by molnar et al. to allow influx of additional energy from novel terrestrial foods (lesser snow geese, eggs, caribou) that polar bears currently consume as part of a mixed diet while on land. we calculated the un ... | 2015 | 26061693 |
| mercury and cortisol in western hudson bay polar bear hair. | non-invasive methods of assessing animal health and life history are becoming increasingly popular in wildlife research; hair samples from polar bears (ursus maritimus), are being used to study an ever broader range of anthropogenic and endocrine compounds. a number of contaminants are known to disrupt endocrine function in polar bears. however, the relationship between mercury and cortisol remains unknown, although mercury is an endocrine disruptor in other species. here, we examine the relatio ... | 2015 | 26044932 |
| ironic effects as reflexive responses: evidence from word frequency effects on involuntary subvocalizations. | in ironic processing, one is more likely to think about something (e.g., white bears) when instructed to not think about that thing. to further investigate this phenomenon involving cognitive control, in the reflexive imagery task (rit), participants are instructed to not subvocalize the names of visual objects. on the majority of the trials, participants fail to suppress such subvocalizations. this finding supports theorizing that conscious thoughts can be triggered by external stimuli in a man ... | 2015 | 26005914 |
| fundamental measure theory for the electric double layer: implications for blue-energy harvesting and water desalination. | capacitive mixing (capmix) and capacitive deionization (cdi) are promising candidates for harvesting clean, renewable energy and for the energy efficient production of potable water, respectively. both capmix and cdi involve water-immersed porous carbon (supercapacitors) electrodes at voltages of the order of hundreds of millivolts, such that counter-ionic packing is important for the electric double layer (edl) which forms near the surfaces of these porous materials. thus, we propose a density ... | 2015 | 25923717 |
| physiologically-based pharmacokinetic modelling of immune, reproductive and carcinogenic effects from contaminant exposure in polar bears (ursus maritimus) across the arctic. | polar bears (ursus maritimus) consume large quantities of seal blubber and other high trophic marine mammals and consequently have some of the highest tissue concentrations of organohalogen contaminants (ohcs) among arctic biota. in the present paper we carried out a risk quotient (rq) evaluation on ohc-exposed polar bears harvested from 1999 to 2008 and from 11 circumpolar subpopulations spanning from alaska to svalbard in order to evaluate the risk of ohc-mediated reproductive effects (embryot ... | 2015 | 25825130 |
| a review of infectious agents in polar bears (ursus maritimus) and their long-term ecological relevance. | disease was a listing criterion for the polar bear (ursus maritimus) as threatened under the endangered species act in 2008; it is therefore important to evaluate the current state of knowledge and identify any information gaps pertaining to diseases in polar bears. we conducted a systematic literature review focused on infectious agents and associated health impacts identified in polar bears. overall, the majority of reports in free-ranging bears concerned serosurveys or fecal examinations with ... | 2015 | 25791679 |
| trichinella spp. imported with live animals and meat. | nematodes of the genus trichinella are widely distributed throughout the world in omnivorous and carnivorous animals (mammals, birds, and reptiles) and in incidental hosts. to prevent the transmission of these zoonotic parasites to humans, meat samples from trichinella spp. susceptible animals are tested at the slaughterhouse or in game processing plants. the aim of the present review was to collect documented cases on trichinella infected animals, meat, or meat derived products which reached th ... | 2015 | 25754352 |
| hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (ursus maritimus). | as a top predator in the arctic food chain, polar bears (ursus maritimus) are exposed to high levels of persistent organic pollutants (pops). because several of these compounds have been reported to alter endocrine pathways, such as the steroidogenesis, potential disruption of the sex steroid synthesis by pops may cause implications for reproduction by interfering with ovulation, implantation and fertility. blood samples were collected from 15 female polar bears in svalbard (norway) in april 200 ... | 2015 | 25725300 |
| the effects of sleep deprivation on dissociation and profiles of mood, and its association with biochemical changes. | sleep deprivation is a method, which has being used in order to comprehend the functions of sleep both in healthy individuals and for the patients of depression with in treatment, for a long time. the objective of our present study is to examine the relation between hormonal values, which are known for being related to the effects of these said changes determined in the mood, dissociation and thought suppression in healthy individuals after one night of sleep deprivation implementation. | 2015 | 28360682 |
| brain region-specific perfluoroalkylated sulfonate (pfsa) and carboxylic acid (pfca) accumulation and neurochemical biomarker responses in east greenland polar bears (ursus maritimus). | perfluoroalkyl substances (pfass) is a growing class of contaminants in the arctic environment, and include the established perfluorinated sulfonates (pfsas; especially perfluorooctane sulfonate (pfos)) and carboxylic acids (pfcas). pfsas and pfcas of varying chain length have been reported to bioaccumulate in lipid rich tissues of the brain among other tissues such as liver, and can reach high concentrations in top predators including the polar bear. pfca and pfsa bioaccummulation in the brain ... | 2015 | 25682255 |
| environmental contaminants activate human and polar bear (ursus maritimus) pregnane x receptors (pxr, nr1i2) differently. | many persistent organic pollutants (pops) accumulate readily in polar bears because of their position as apex predators in arctic food webs. the pregnane x receptor (pxr, formally nr1i2, here proposed to be named promiscuous xenobiotic receptor) is a xenobiotic sensor that is directly involved in metabolizing pathways of a wide range of environmental contaminants. | 2015 | 25680588 |
| establishing a definition of polar bear (ursus maritimus) health: a guide to research and management activities. | the meaning of health for wildlife and perspectives on how to assess and measure health, are not well characterized. for wildlife at risk, such as some polar bear (ursus maritimus) subpopulations, establishing comprehensive monitoring programs that include health status is an emerging need. environmental changes, especially loss of sea ice habitat, have raised concern about polar bear health. effective and consistent monitoring of polar bear health requires an unambiguous definition of health. w ... | 2015 | 25679818 |
| penile density and globally used chemicals in canadian and greenland polar bears. | industrially produced chemicals have been a major environmental concern across our entire globe since the onset of rapid industrial development around the early 1900. many of the substances being used are known to be endocrine disrupting chemicals (edcs) and are also known to be long-range dispersed and to biomagnify to very high concentrations in the tissues of arctic apex predators such as polar bears (ursus maritimus). a major concern relating to edcs is their effects on vital organ-tissues s ... | 2015 | 25601730 |
| white bear effects in language production: evidence from the prosodic realization of adjectives. | a central problem in recent research on speech production concerns the question to what extent speakers adapt their linguistic expressions to the needs of their addressees. it is claimed that speakers sometimes leak information about objects that are only visible for them and not for their listeners. previous research only takes the occurrence of adjectives as evidence for the leakage of privileged information. the present study hypothesizes that leaked information is also encoded in the prosody ... | 2014 | 25536844 |
| himalayan 'yeti' dna: polar bear or dna degradation? a comment on 'genetic analysis of hair samples attributed to yeti' by sykes et al. (2014). | | 2015 | 25520353 |
| free energy calculations of crystalline hard sphere complexes using density functional theory. | recently developed fundamental measure density functional theory (fmt) is used to study binary hard sphere (hs) complexes in crystalline phases. by comparing the excess free energy, pressure, and phase diagram, we show that the fundamental measure functional yields good agreements to the available simulation results of ab, ab2, and ab13 crystals. furthermore, we use this functional to study the hs models of five binary crystals, cu5zr(c15b), cu51zr14(β), cu10zr7(ϕ), cuzr(b2), and cuzr2(c11b), wh ... | 2015 | 25496266 |
| thyroid hormones and deiodinase activity in plasma and tissues in relation to high levels of organohalogen contaminants in east greenland polar bears (ursus maritimus). | previous studies have shown relationships between organohalogen contaminants (ohcs) and circulating levels of thyroid hormones (ths) in arctic wildlife. however, there is a lack of knowledge concerning the possible functional effects of ohcs on th status in target tissues for th-dependent activity. the relationships between circulating (plasma) levels of ohcs and various th variables in plasma as well as in liver, muscle and kidney tissues from east greenland sub-adult polar bears (ursus maritim ... | 2015 | 25460663 |
| 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. | 2014 | 25426720 |
| prevalence and spatio-temporal variation of an alopecia syndrome in polar bears (ursus maritimus) of the southern beaufort sea. | alopecia (hair loss) has been observed in several marine mammal species and has potential energetic consequences for sustaining a normal core body temperature, especially for arctic marine mammals routinely exposed to harsh environmental conditions. polar bears (ursus maritimus) rely on a thick layer of adipose tissue and a dense pelage to ameliorate convective heat loss while moving between sea ice and open water. from 1998 to 2012, we observed an alopecia syndrome in polar bears from the south ... | 2015 | 25375943 |
| 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 ... | 2014 | 25314835 |
| [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. | 2014 | 25286544 |
| 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, ... | 2014 | 25277947 |
| 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 ... | 2014 | 25273481 |
| 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 ... | 2014 | 25264143 |
| 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 ... | 2014 | 25212698 |
| thinking about white bears: fertility issues in young breast cancer survivors. | | 2015 | 25200632 |
| design of a 9k illumina beadchip for polar bears (ursus maritimus) from rad and transcriptome sequencing. | single-nucleotide polymorphisms (snps) offer numerous advantages over anonymous markers such as microsatellites, including improved estimation of population parameters, finer-scale resolution of population structure and more precise genomic dissection of quantitative traits. however, many snps are needed to equal the resolution of a single microsatellite, and reliable large-scale genotyping of snps remains a challenge in nonmodel species. here, we document the creation of a 9k illumina infinium ... | 2015 | 25187336 |
| 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. | 2014 | 25170590 |
| 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 ... | 2014 | 25101837 |
| the relationship between thought suppression and retrieval-induced forgetting: an analysis of witness memories. | the aim of the present research was to examine the relationship between individual differences in thought suppression and retrieval-induced forgetting (rif) in witness-like situations. we predicted that people who are more prone to suppress undesired thoughts and memories would demonstrate a stronger rif effect. consistent with findings obtained in a us sample (blumberg in personal individ differ 29:943-950, 2000), results of a preliminary study (study 1) confirmed the three-factor structure of ... | 2015 | 25064740 |
| 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 ... | 2014 | 25006979 |
| 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 ... | 2014 | 25000711 |
| evaluation of polar bear movement patterns in relation to sea ice drift. | | 2014 | 24985513 |
| individual effects of seasonal changes, visitor density, and concurrent bear behavior on stereotypical behaviors in captive polar bears (ursus maritimus). | stereotypical behaviors in captive polar bears (ursus maritimus) can be detrimental to their welfare. these behaviors can be reduced through enrichment programs but are often not completely eliminated, so identifying potential triggers is important. the present study investigated the influences of seasonal changes, visitor density, and concurrent bear activity on stereotypical behaviors exhibited by 3 captive polar bears at the toronto zoo. all bears exhibited these behaviors; however, individua ... | 2015 | 24933263 |
| 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 ... | 2014 | 24724772 |
| 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 ... | 2014 | 24712179 |
| 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 ... | 2014 | 24712164 |
| 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 ... | 2014 | 24634735 |
| polar bear encephalitis: establishment of a comprehensive next-generation pathogen analysis pipeline for captive and free-living wildlife. | this report describes three possibly related incidences of encephalitis, two of them lethal, in captive polar bears (ursus maritimus). standard diagnostic methods failed to identify pathogens in any of these cases. a comprehensive, three-stage diagnostic 'pipeline' employing both standard serological methods and new dna microarray and next generation sequencing-based diagnostics was developed, in part as a consequence of this initial failure. this pipeline approach illustrates the strengths, wea ... | 2014 | 24534459 |
| the 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 ... | 2014 | 24439617 |
| 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- ... | 2014 | 24437898 |
| 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 ... | 2014 | 24427306 |
| 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 ... | 2014 | 24418048 |
| 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. | 2014 | 24387924 |
| 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 ... | 2014 | 24382481 |
| the fur of mammals in exposed environments; do crypsis and thermal needs necessarily conflict? the polar bear and marsupial koala compared. | the furs of mammals have varied and complex functions. other than for thermoregulation, fur is involved in physical protection, sensory input, waterproofing and colouration, the latter being important for crypsis or camouflage. some of these diverse functions potentially conflict. we have investigated how variation in cryptic colouration and thermal features may interact in the coats of mammals and influence potential heat inflows from solar radiation, much of which is outside the visible spectr ... | 2014 | 24366474 |
| 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 ... | 2013 | 24359342 |
| 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 ... | 2013 | 24205025 |
| 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). | 2014 | 24151970 |
| 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 ... | 2013 | 24107529 |
| 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 ... | 2013 | 24102001 |
| 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. | 2013 | 23539581 |
| 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 ... | 2013 | 24019883 |
| 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 ... | 2013 | 23984296 |
| 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 ... | 2013 | 23920361 |
| 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 ... | 2013 | 23856758 |
| [the possibility of using high resolution satellite images for detection of marine mammals]. | the possibility of using modern systems of remote sensing in the optical range from high spatial resolution satellites for detection of marine mammals and traces of their activity is investigated. an image obtained by the geoeye satellite within the feac project was used for the analysis. the image covers herald island and adjacent waters, which are a part of the wrangel island reserve, during the seasonal thaw (june 2009). it is shown that marine mammals (polar bears, walruses, and whales) can ... | 2016 | 23789427 |
| 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. ... | 2013 | 23763488 |
| 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 ... | 2013 | 23716301 |