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a body composition model to estimate mammalian energy stores and metabolic rates from body mass and body length, with application to polar bears.many species experience large fluctuations in food availability and depend on energy from fat and protein stores for survival, reproduction and growth. body condition and, more specifically, energy stores thus constitute key variables in the life history of many species. several indices exist to quantify body condition but none can provide the amount of stored energy. to estimate energy stores in mammals, we propose a body composition model that differentiates between structure and storage of an ...200919617423
is dietary mercury of neurotoxicological concern to wild polar bears (ursus maritimus)?polar bears (ursus maritimus) are exposed to high concentrations of mercury because they are apex predators in the arctic ecosystem. although mercury is a potent neurotoxic heavy metal, it is not known whether current exposures are of neurotoxicological concern to polar bears. we tested the hypotheses that polar bears accumulate levels of mercury in their brains that exceed the estimated lowest observable adverse effect level (20 microg/g dry wt) for mammalian wildlife and that such exposures ar ...200918717617
methyl mercury production and loss in arctic soil.mercury has been found in polar bears and other top predators in the arctic at concentrations that pose a risk to the indigenous population, however, the means by which this occurs is uncertain. there has been extensive research on the atmospheric cycling of mercury but little is known about mercury cycling in arctic terrestrial ecosystems. the objective of this study was to determine whether wet sedge meadow soils within the truelove lowlands, devon island, nt, canada (75 degrees 33'n, 84 degre ...200919081608
mindfulness-based cognitive therapy may reduce thought suppression in previously suicidal participants: findings from a preliminary study.thought suppression is a strategy aimed at mental control that may paradoxically increase the frequency of unwanted thoughts. this preliminary study examined effects of mindfulness-based cognitive therapy (mbct) on thought suppression and depression in individuals with past depression and suicidality.200919254446
does taurine deficiency cause metabolic bone disease and rickets in polar bear cubs raised in captivity?rickets and fractures have been reported in captive polar bears. taurine (tau) is key for the conjugation of ursodeoxycholic acid (udca), a bile acid unique to bears. since tau-conjugated udca optimizes fat and fat-soluble vitamin absorption, we asked if tau deficiency could cause vitamin d malabsorption and lead to metabolic bone disease in captive polar bears. we measured tau levels in plasma (p) and whole blood (wb) from captive and free-ranging cubs and adults, and vitamin d3 and tau concent ...200919239163
families in space: relatedness in the barents sea population of polar bears (ursus maritimus).the kin structure and dispersal pattern of polar bears (ursus maritimus) of the barents sea was investigated during the spring mating season using two complementary approaches. first, individual genotypes based on the analyses of 27 microsatellite loci of 583 polar bears were related to field information gathered from 1146 bears in order to reconstruct the animals' pedigrees and to infer geographical distances between adult bears of different relatedness categories. according to the data, the me ...200919175504
don't worry and beware of white bears: thought suppression in anxiety patients.the ability to suppress unwanted thoughts was investigated in patients with generalized anxiety disorder (gad; n = 29), speech phobics (n = 25), and nonanxious controls (n = 28). all participants spent 5 minutes thinking aloud about anything that came to mind while trying not to think of white bears. in another task, they thought aloud for 5 minutes while trying not to think of their main worry. intrusions of unwanted thoughts were signaled by button presses and recorded on tape. in accordance w ...20099549608
[group infection with trichinella from the meat of a polar bear in the soviet arctic region]. 200913450973
polar bear trackingvia satellite. 2009687726
individual differences in thought suppression. the white bear suppression inventory: factor structure, reliability, validity and correlates.the white bear suppression inventory [wbsi; wegner, d.m. & zanakos, s. (1994), journal of personality, 62, 615-640] is a self-report questionnaire measuring people's general tendency to suppress unwanted negative thoughts. the current article describes two studies investigating the reliability, factor structure, validity, and correlates of the wbsi. study 1 (n = 172) showed that the wbsi is a reliable instrument in terms of internal consistency and test-retest stability. factor analyses of the w ...20108687372
the relationship between thought suppression and smoking cessation.intrusive thoughts (e.g., anxiety, depression, substance use) are among the most salient symptoms of clinical problems. therefore, methods of thought suppression have received considerable attention. however, some studies have found that attempts to suppress thoughts precipitate an increase in thoughts. in the case of substance abuse, such thoughts could serve as cues for further use. this study examined the association between thought suppression and quitting smoking in a sample of current and ...201011456074
withdrawn: health effects from long-range transported contaminants in arctic top predators: an integrated review based on studies of polar bears and relevant model species.the publisher regrets that this article is an accidental duplication of an article that has already been published, doi:10.1016/j.envint.2010.03.002. the duplicate article has therefore been withdrawn.201020053456
why the white bear is still there: electrophysiological evidence for ironic semantic activation during thought suppression.much research has focused on the paradoxical effects of thought suppression, leading to the viewpoint that increases in unwanted thoughts are due to an ironic monitoring process that increases the activation of the very thoughts one is trying to rid from consciousness. however, it remains unclear from behavioral findings whether suppressed thoughts become more accessible during the act of suppression. in the current study, event-related potentials were recorded while participants suppressed or e ...201020044982
in vitro assay shows that pcb metabolites completely saturate thyroid hormone transport capacity in blood of wild polar bears (ursus maritimus).persistent chemicals accumulate in the arctic environment due to their chemical reactivity and physicochemical properties and polychlorinated biphenyls (pcbs) are the most concentrated pollutant class in polar bears (ursus maritimus). metabolism of pcb and polybrominated biphenyl ether (pbde) flame-retardants alter their toxicological properties and these metabolites are known to interfere with the binding of thyroid hormone (th) to transthyretin (ttr) in rodents and humans. in polar bear plasma ...201020345174
effects of thought suppression on eating behaviour in restrained and non-restrained eaters.recent research has shown that suppressing food related thoughts can cause a subsequent increase in consumption relative to groups not suppressing, or thinking about food. the present study examined whether the effects of thought suppression on subsequent eating behaviour would interact with participants restrained eating status. one hundred and sixteen female participants were split into three groups. one third suppressed thoughts of chocolate, one third thought about chocolate and the final th ...201020152872
greenhouse gas mitigation can reduce sea-ice loss and increase polar bear persistence.on the basis of projected losses of their essential sea-ice habitats, a united states geological survey research team concluded in 2007 that two-thirds of the world's polar bears (ursus maritimus) could disappear by mid-century if business-as-usual greenhouse gas emissions continue. that projection, however, did not consider the possible benefits of greenhouse gas mitigation. a key question is whether temperature increases lead to proportional losses of sea-ice habitat, or whether sea-ice cover ...201021164484
contribution of synthetic and naturally occurring organobromine compounds to bromine mass in marine organisms.an extraction, separation, and purification method was developed for the identification and quantification of total bromine (tbr), extractable organobromine (eobr), and five classes of identified eobrs. instrumental neutron activation analysis (inaa) was utilized to quantify eobr and tbr. the method was then applied to liver samples of tuna, albatross, and polar bear collected from remote marine locations. polybrominated biphenyls (pbbs), polybrominated diphenyl ethers (pbdes), bromophenols (brp ...201020704201
i suppress, therefore i smoke: effects of thought suppression on smoking behavior.thought suppression is a method frequently employed by individuals who are trying to control their thoughts and behaviors. although this strategy is known to actually increase unwanted thoughts, it is unclear whether thought suppression also results in behavioral rebound. the study presented in this article investigated the effects of suppressing thoughts of smoking in everyday life on the number of cigarettes subsequently smoked. study participants recorded their daily cigarette intake and stre ...201020660892
suppressing the white bears interacts with anxiety sensitivity in the prediction of mood and anxiety symptoms.suppression is a commonly used strategy to manage unwanted thoughts by attempting to actively remove them from awareness. however, research has shown that this cognitive strategy often results in the paradoxical effect of increasing the frequency of unwanted thoughts. while the association between thought suppression and mood and anxiety symptoms has been repeatedly demonstrated, relations between this cognitive strategy and other anxiety risk factors such as anxiety sensitivity (as) are unexplo ...201020640051
polar bears, antibiotics, and the evolving ribosome (nobel lecture).high-resolution structures of ribosomes, the cellular machines that translate the genetic code into proteins, revealed the decoding mechanism, detected the mrna path, identified the sites of the trna molecules in the ribosome, elucidated the position and the nature of the nascent proteins exit tunnel, illuminated the interactions of the ribosome with non-ribosomal factors, such as the initiation, release and recycling factors, and provided valuable information on ribosomal antibiotics, their bin ...201020535730
reduced body size and cub recruitment in polar bears associated with sea ice decline.rates of reproduction and survival are dependent upon adequate body size and condition of individuals. declines in size and condition have provided early indicators of population decline in polar bears (ursus maritimus) near the southern extreme of their range. we tested whether patterns in body size, condition, and cub recruitment of polar bears in the southern beaufort sea of alaska were related to the availability of preferred sea ice habitats and whether these measures and habitat availabili ...201020437962
polar bear alert! 201020364487
interactive effects of catastrophizing and suppression on responses to acute pain: a test of an appraisal x emotion regulation model.we examined whether people who tend to catastrophize about pain and who also attempt to regulate negative thoughts and feelings through suppression may represent a distinct subgroup of individuals highly susceptible to pain and distress. ninety-seven healthy normal participants underwent a 4-min ischemic pain task followed by a 2-min recovery period. self-reported pain and distress was recorded during the task and every 20 s during recovery. participants completed the pain catastrophizing scale ...201020101453
use of hyaluronidase to improve chemical immobilization of free-ranging polar bears (ursus maritimus).we assessed the efficacy and safety of hyaluronidase to improve chemical immobilization of free-ranging polar bears (ursus maritimus) captured from helicopter by remote drug delivery along the ontario coast line of northwestern james bay and southern hudson bay during september 2005 and october 2007. we used a single blind study design in which one person prepared and loaded all darts without the shooter knowing whether hyaluronidase (150 iu per dart) or sterile water was added to the immobilizi ...201020090038
mercury-associated dna hypomethylation in polar bear brains via the luminometric methylation assay: a sensitive method to study epigenetics in wildlife.in this paper we describe a novel approach that may shed light on the genomic dna methylation of organisms with non-resolved genomes. the luminometric methylation assay (luma) is permissive for genomic dna methylation studies of any genome as it relies on the use of methyl-sensitive and -insensitive restriction enzymes followed by polymerase extension via pyrosequencing technology. here, luma was used to characterize genomic dna methylation in the lower brain stem region from 47 polar bears subs ...201020002585
survival and breeding of polar bears in the southern beaufort sea in relation to sea ice.1. observed and predicted declines in arctic sea ice have raised concerns about marine mammals. in may 2008, the us fish and wildlife service listed polar bears (ursus maritimus) - one of the most ice-dependent marine mammals - as threatened under the us endangered species act. 2. we evaluated the effects of sea ice conditions on vital rates (survival and breeding probabilities) for polar bears in the southern beaufort sea. although sea ice declines in this and other regions of the polar basin h ...201019754681
climate change threatens polar bear populations: a stochastic demographic analysis.the polar bear (ursus maritimus) depends on sea ice for feeding, breeding, and movement. significant reductions in arctic sea ice are forecast to continue because of climate warming. we evaluated the impacts of climate change on polar bears in the southern beaufort sea by means of a demographic analysis, combining deterministic, stochastic, environment-dependent matrix population models with forecasts of future sea ice conditions from ipcc general circulation models (gcms). the matrix population ...201021058549
the role of diet on long-term concentration and pattern trends of brominated and chlorinated contaminants in western hudson bay polar bears, 1991-2007.adipose tissue was sampled from the western hudson bay (whb) subpopulation of polar bears at intervals from 1991 to 2007 to examine temporal trends of pcb and ocp levels both on an individual and sum-(∑-)contaminant basis. we also determined levels and temporal trends of emerging polybrominated diphenyl ethers (pbdes), hexabromocyclododecane (hbcd), polybrominated biphenyls (pbbs) and other current-use brominated flame retardants. over the 17-year period, ∑ddt (and p,p'-dde, p,p'-ddd, p,p'-ddt) ...201020870269
arctic reality.the threat to the hudson bay polar bears highlights the reality of a changing climate under attack from sceptics.201020705539
formal behavioral evaluation of enrichment programs on a zookeeper's schedule: a case study with a polar bear (ursus maritimus) at the bronx zoo.we conducted a brief study of the effectiveness of environmental enrichment for a polar bear at the bronx zoo with two objectives in mind. first we wanted to determine if a novel method of collecting data that easily fits into a zookeeper's work routine would produce usable data and if so, we wanted to evaluate the effectiveness of some new items that had been purchased for enriching the polar bear in reducing his pacing behavior. observations were recorded for 119 days over a period of 5 months ...201019373879
genetic variation, relatedness, and effective population size of polar bears (ursus maritimus) in the southern beaufort sea, alaska.polar bears (ursus maritimus) are unique among bears in that they are adapted to the arctic sea ice environment. genetic data are useful for understanding their evolution and can contribute to management. we assessed parentage and relatedness of polar bears in the southern beaufort sea, alaska, with genetic data and field observations of age, sex, and mother-offspring and sibling relationships. genotypes at 14 microsatellite dna loci for 226 bears indicate that genetic variation is comparable to ...201019633212
free energies, vacancy concentrations, and density distribution anisotropies in hard-sphere crystals: a combined density functional and simulation study.we perform a comparative study of the free energies and the density distributions in hard-sphere crystals using monte carlo simulations and density functional theory (employing fundamental measure functionals). using a recently introduced technique [t. schilling and f. schmid, j. chem. phys. 131, 231102 (2009)] we obtain crystal free energies to a high precision. the free energies from fundamental measure theory are in good agreement with the simulation results and demonstrate the applicability ...201021230476
climate change: the prospects for polar bears. 201021164475
marine mammal blubber reference and control materials for use in the determination of halogenated organic compounds and fatty acids.the national institute of standards and technology (nist) has a diverse collection of control materials derived from marine mammal blubber, fat, and serum. standard reference material (srm) 1945 organics in whale blubber was recertified for polychlorinated biphenyl (pcb) congeners, organochlorine pesticides, and polybrominated diphenyl ether (pbde) congeners. srm 1945 has also been assigned mass fraction values for compounds not frequently determined in marine samples including toxaphene congene ...201020238106
levels and trends of poly- and perfluorinated compounds in the arctic environment.poly- and perfluorinated organic compounds (pfcs) are ubiquitous in the arctic environment. several modeling studies have been conducted in attempt to resolve the dominant transport pathway of pfcs to the arctic-atmospheric transport of precursors versus direct transport via ocean currents. these studies are generally limited by their focus on perfluorooctanoate (pfoa) fluxes to arctic seawater and thus far have only used fluorotelomer alcohols (ftohs) and sulfonamide alcohols as inputs for vola ...201020493516
new support for polar bears and tigers. 201021210537
complete mitochondrial genome of a pleistocene jawbone unveils the origin of polar bear.the polar bear has become the flagship species in the climate-change discussion. however, little is known about how past climate impacted its evolution and persistence, given an extremely poor fossil record. although it is undisputed from analyses of mitochondrial (mt) dna that polar bears constitute a lineage within the genetic diversity of brown bears, timing estimates of their divergence have differed considerably. using next-generation sequencing technology, we have generated a complete, hig ...201020194737
brucella species survey in polar bears (ursus maritimus) of northern alaska.we report on the presence of specific antibodies to brucella spp. and yersinia enterocolitica in polar bears (ursus maritimus) from northern alaska (southern beaufort sea) during 2003-2006. based on numerous known stressors (e.g., climate change and loss of sea ice habitat, contaminants), there is increased concern regarding the status of polar bears. considering these changes, it is important to assess exposure to potentially pathogenic organisms and to improve understanding of transmission pat ...201020688674
trans-generational and neonatal humoral immune responses in west greenland sledge dogs (canis familiaris) exposed to organohalogenated environmental contaminants.previous investigations in the arctic have suggested ohc (organohalogen contaminant) induced immune toxic effects on e.g. polar bears (ursus maritimus). we therefore studied the dietary impact from minke whale blubber (balaenoptera acutorostrata), rich in polyunsaturated fatty acids and ohcs, on the humoral immunity of 7 captive west greenland sledge dog (canis familiaris) bitches and their 4 pups constituting a sentinel model species for polar bears. a control group was composed of 8 bitches an ...201020832100
biomechanical consequences of rapid evolution in the polar bear lineage.the polar bear is the only living ursid with a fully carnivorous diet. despite a number of well-documented craniodental adaptations for a diet of seal flesh and blubber, molecular and paleontological data indicate that this morphologically distinct species evolved less than a million years ago from the omnivorous brown bear. to better understand the evolution of this dietary specialization, we used phylogenetic tests to estimate the rate of morphological specialization in polar bears. we then us ...201021079768
polychlorinated biphenyls and their hydroxylated metabolites (oh-pcbs) in the blood of toothed and baleen whales stranded along japanese coastal waters.in this study, we determined the residue levels and patterns of polychlorinated biphenyls (pcbs) and hydroxylated pcbs (oh-pcbs) in the blood from eight species of toothed whales and three species of baleen whales stranded along the japanese coast during 1999-2007. penta- through hepta-chlorinated pcb congeners were the dominant homologue groups in all cetaceans. in contrast, specific differences in the distribution of dominant oh-pcb isomers and homologues were found among the cetacean species. ...201020426459
the value of a polar bear: evaluating the role of a multiple-use resource in the nunavut mixed economy.the polar bear (ursus maritimus) is a common pool resource that contributes to both the subsistence and monetary aspects of the nunavut mixed economy through its use as food, the sale of hides in the fur trade, and sport hunt outfitting. sport hunting is more financially profitable than subsistence hunting; however, the proportion of the polar bear quota devoted to the sport hunt has become relatively stable at approximately 20% across nunavut. this ratio suggests local inuit organizations are n ...201020648983
bacterial diversity in faeces from polar bear (ursus maritimus) in arctic svalbard.polar bears (ursus maritimus) are major predators in the arctic marine ecosystem, feeding mainly on seals, and living closely associated with sea ice. little is known of their gut microbial ecology and the main purpose of this study was to investigate the microbial diversity in faeces of polar bears in svalbard, norway (74-81 degrees n, 10-33 degrees e). in addition the level of blatem alleles, encoding ampicillin resistance (ampr) were determined. in total, ten samples were collected from ten i ...201020074323
trichinella infection in a hunting community in east greenland.trichinella nativa infection (trichinellosis) is highly prevalent in arctic wildlife, but the human burden of trichinellosis in present-day greenland is unknown. the study aimed to determine trichinella seroprevalence in an eastern greenlandic hunting community and to evaluate risk factors for seropositivity. overall, 998 inhabitants aged 10 years in the ammassalik municipality were tested for trichinella-specific igg antibodies. background information was obtained from questionnaires. seroposit ...201020144253
femoral fracture repair using a locking plate technique in an adult captive polar bear (ursus maritimus).to report successful femoral fracture repair in a polar bear.201020210973
health effects from long-range transported contaminants in arctic top predators: an integrated review based on studies of polar bears and relevant model species.the aim of this review is to provide a thorough overview of the health effects from the complexed biomagnified mixture of long-range transported industrial organochlorines (ocs), polybrominated diphenyl ethers (pbdes), perfluorinated compounds (pfcs) and mercury (hg) on polar bear (ursus maritimus) health. multiple scientific studies of polar bears indicate negative relationships between exposure to these contaminants and health parameters; however, these are all of a correlative nature and do n ...201020398940
biomonitoring in greenland: human biomarkers of exposure and effects - a short review.since 1997 the arctic monitoring and assessment programme (amap) has produced integrated assessment reports on the status of and trends in environmental persistent organic pollutants (pops) in the arctic ecosystem. three reports on biomonitoring pops and their health risks for arctic populations were published in 1998, 2002, and 2009.201020572746
morbillivirus and toxoplasma exposure and association with hematological parameters for southern beaufort sea polar bears: potential response to infectious agents in a sentinel species.arctic temperatures are increasing in response to greenhouse gas forcing and polar bears have already responded to changing conditions. declines in body stature and vital rates have been linked to warming-induced loss of sea-ice. as food webs change and human activities respond to a milder arctic, exposure of polar bears and other arctic marine organisms to infectious agents may increase. because of the polar bear's status as arctic ecosystem sentinel, polar bear health could provide an index of ...201020607348
hematology of southern beaufort sea polar bears (2005-2007): biomarker for an arctic ecosystem health sentinel.declines in sea-ice habitats have resulted in declining stature, productivity, and survival of polar bears in some regions. with continuing sea-ice declines, negative population effects are projected to expand throughout the polar bear's range. precise causes of diminished polar bear life history performance are unknown, however, climate and sea-ice condition change are expected to adversely impact polar bear (ursus maritimus) health and population dynamics. as apex predators in the arctic, pola ...201020617361
trichinella nativa in iceland: an example of trichinella dispersion in a frigid zone.in most arctic and subarctic regions, trichinella nativa is a common zoonotic pathogen circulating among wild carnivores. the polar bear (ursus maritimus) is one of the most important reservoirs for t. nativa in frigid zones. in iceland, trichinella infection has never been detected in the local wildlife, despite the presence of one of the host species, the arctic fox (alopex lagopus). in 2008, one of two polar bears that had swum to iceland's coast was found to have been infected with trichinel ...201019732473
exposure and effects assessment of persistent organohalogen contaminants in arctic wildlife and fish.persistent organic pollutants (pops) encompass an array of anthropogenic organic and elemental substances and their degradation and metabolic byproducts that have been found in the tissues of exposed animals, especially pops categorized as organohalogen contaminants (ohcs). ohcs have been of concern in the circumpolar arctic for decades. for example, as a consequence of bioaccumulation and in some cases biomagnification of legacy (e.g., chlorinated pcbs, ddts and chls) and emerging (e.g., bromin ...201019910021
new insights into the morphology, molecular characterization and identification of baylisascaris transfuga (ascaridida, ascarididae).species ranked within the genus baylisascaris (ascaridida, ascarididae) have been implicated in clinical and subclinical intestinal diseases in their natural hosts (e.g., raccoons and bears) as well as in life-threatening larva migrans syndromes in a number of incidental hosts, including humans. following the diagnosis of baylisascaris transfuga infestation in two captive polar bears, living in the zoo park of pistoia (tuscany, italy), nematodes (n=300; both sexes) have been characterized by mor ...201020947254
polychlorinated naphthalenes in polar environments--a review.polychlorinated naphthalenes (pcns) consist of naphthalene substituted with 1-8 chlorines, yielding 75 possible congeners. they were formerly used in industry, occur at trace levels in commercial pcb mixtures, and have current sources in combustion processes. pcns are widespread in arctic air with higher levels in the european arctic. concentrations were higher during the cold months in arctic canada and russia, but no seasonality was noted in subarctic canada and greenland. "marker" congeners i ...201019892388
serosurvey for trichinella in polar bears (ursus maritimus) from svalbard and the barents sea.blood samples of live-caught polar bears (ursus maritimus) from svalbard collected 1991-2000 (period 1) and 2006-2008 (period 2) and from the pack ice of the barents sea collected in period 1, were assayed for antibodies against trichinella spp. by elisa. of 54 cubs-of-the-year included in the period 1 sample, 53 were seronegative, indicating that exposure to trichinella infected meat is uncommon during the first months of life for polar bears in the svalbard region. of 30 mother-offspring pairs ...201020797484
a screening of persistent organohalogenated contaminants in hair of east greenland polar bears.in this pilot study, we report on levels of persistent organohalogenated contaminants (ohcs) in hair of polar bears (ursus maritimus) from east greenland sampled between 1999 and 2001. to our knowledge, this is the first study on the validation of polar bear hair as a non-invasive matrix representative of concentrations and profiles in internal organs and blood plasma. because of low sample weights (13-140mg), only major bioaccumulative ohcs were detected above the limit of quantification: five ...201020800875
toxicokinetics of mercury in blood compartments and hair of fish-fed sled dogs.abstract:201122152014
blood-based biomarkers of selenium and thyroid status indicate possible adverse biological effects of mercury and polychlorinated biphenyls in southern beaufort sea polar bears.we examined biomarkers of selenium status (whole blood se; serum se; glutathione peroxidase activity) and thyroid status (concentrations and ratios of thyroxine, t4; tri-iodothyronine, t3; albumin) in polar bears to assess variations among cohorts, and relationships to circulating concentrations of contaminants. concentrations of total mercury (hg) in whole blood were similar among cohorts (prime aged males and females, older animals, ages≥16 years, and young animals, ages 1-5 years; 48.44±35. 8 ...201121903210
rickets in polar bear cubs: is there a lesson for human infants? 201120639682
comparative hepatic microsomal biotransformation of selected pbdes, including decabromodiphenyl ether, and decabromodiphenyl ethane flame retardants in arctic marine-feeding mammals.the present study assessed and compared the oxidative and reductive biotransformation of brominated flame retardants, including established polybrominated diphenyl ethers (pbdes) and emerging decabromodiphenyl ethane (dbdpe) using an in vitro system based on liver microsomes from various arctic marine-feeding mammals: polar bear (ursus maritimus), beluga whale (delphinapterus leucas), and ringed seal (pusa hispida), and in laboratory rat as a mammalian model species. greater depletion of fully b ...201121437940
are terrestrial mammals the source for exposure of polar bear to brucella spp. in alaska? 201121441203
temporal trends and future predictions of mercury concentrations in northwest greenland polar bear (ursus maritimus) hair.hair samples from 117 northwest greenland polar bears (ursus maritimus) were taken during 1892-2008 and analyzed for total mercury (hereafter hg). the sample represented 28 independent years and the aim of the study was to analyze for temporal hg trends. mercury concentrations showed yearly significant increases of 1.6-1.7% (p < 0.0001) from 1892 to 2008 and the two most recent median concentrations from 2006 and 2008 were 23- to 27-fold higher respectively than baseline level from 1300 a.d. in ...201121214235
comparative analysis of fecal microbiota and intestinal microbial metabolic activity in captive polar bears.the composition of the intestinal microbiota depends on gut physiology and diet. ursidae possess a simple gastrointestinal system composed of a stomach, small intestine, and indistinct hindgut. this study determined the composition and stability of fecal microbiota of 3 captive polar bears by group-specific quantitative pcr and pcr-dgge (denaturing gradient gel electrophoresis) using the 16s rrna gene as target. intestinal metabolic activity was determined by analysis of short-chain fatty acids ...201121358758
organochlorine and metal contaminants in traditional foods from st. lawrence island, alaska.marine mammals (bowhead whale, walrus, and various seals) constitute the major component of the diet of the yupik people of st. lawrence island, alaska. st. lawrence island residents have higher serum concentrations of polychlorinated biphenyls (pcb) than in the general u.s. population. in order to determine potential sources, traditional food samples were collected from 2004 to 2009 and analyzed for pcbs, three chlorinated pesticides, and seven heavy metals (mercury, copper, zinc, arsenic, sele ...201121797772
complete mitochondrial genomes of baylisascaris schroederi, baylisascaris ailuri and baylisascaris transfuga from giant panda, red panda and polar bear.roundworms of the genus baylisascaris are the most common parasitic nematodes of the intestinal tracts of wild mammals, and most of them have significant impacts in veterinary and public health. mitochondrial (mt) genomes provide a foundation for studying epidemiology and ecology of these parasites and therefore may be used to assist in the control of baylisascariasis. here, we determined the complete sequences of mtdnas for baylisascaris schroederi, baylisascaris ailuri and baylisascaris transf ...201121621593
ancient hybridization and an irish origin for the modern polar bear matriline.polar bears (ursus maritimus) are among those species most susceptible to the rapidly changing arctic climate, and their survival is of global concern. despite this, little is known about polar bear species history. future conservation strategies would significantly benefit from an understanding of basic evolutionary information, such as the timing and conditions of their initial divergence from brown bears (u.-áarctos) or their response to previous environmental change.201121737280
blood plasma sample preparation method for the assessment of thyroid hormone-disrupting potency in effect-directed analysis.a sample preparation method combining solid-phase extraction (spe) and liquid-liquid extraction (lle) was developed to be used in effect-directed analysis (eda) of blood plasma. until now such a method was not available. it can be used for extraction of a broad range of thyroid hormone (th)-disruptors from plasma with high recoveries. validation of the method using spiked cow plasma showed good recoveries for hydroxylated polybrominated diphenyl ethers (oh-pbdes; 93.8 -¦ 19.5%), hydroxylated pol ...201121842831
regional contamination versus regional dietary differences: understanding geographic variation in brominated and chlorinated contaminant levels in polar bears.the relative contribution of regional contamination versus dietary differences to geographic variation in polar bear (ursus maritimus) contaminant levels is unknown. dietary variation between alaska, canada, east greenland, and svalbard subpopulations was assessed by muscle nitrogen and carbon stable isotope (δ(15)n, δ(13)c) and adipose fatty acid (fa) signatures relative to their main prey (ringed seals). western and southern hudson bay signatures were characterized by depleted δ(15)n and δ(13) ...201121166451
reproductive cycles of marine mammals.marine mammals conform to the general mammalian reproductive system centered on the hypothalamic-pituitary-gonadal axis. most marine mammals are long-lived and of large body size with lesser reproductive rates than many other animals, a consequence of their interaction with the marine environment where the demands of acquiring resources from the ocean must be balanced with the need for bearing offspring in a suitable place for survival. the degree of spatial and temporal separation of these life ...201120869821
cortisol levels in hair of east greenland polar bears.to demonstrate the ability to assess long-term hypothalamic-pituitary-adrenocortical (hpa) axis activity in polar bears (ursus maritimus), a pilot study was conducted in which cortisol concentrations was analyzed in hair from 7 female (3-19 years) and 10 male (6-19 years) east greenland polar bears sampled in 1994-2006. the hair was chosen as matrix as it is non-invasive, seasonally harmonized, and has been validated as an index of long-term changes in cortisol levels. the samples were categoriz ...201121144554
milk composition in free-ranging polar bears (ursus maritimus) as a model for captive rearing milk formula.the goals of this study were to have an improved understanding of milk composition and to help create a suitable milk formula for cubs raised in captivity. milk samples were evaluated for fat, fatty acids, carbohydrate, vitamin d(3), 25(oh)d(3), vitamin a (retinol), vitamin e (α-tocopherol), protein, and amino acids. total lipids in milk did not differ for cubs (mean ± sem = 26.60 ± 1.88 g/100 ml vs. yearlings 27.80 ± 2.20 g/100 ml). milk lipids were of 23.6% saturated fatty acid for cubs and 22 ...201121246608
setting free the bears: escape from thought suppression.a person who is asked to think aloud while trying not to think about a white bear will typically mention the bear once a minute. so how can people suppress unwanted thoughts? this article examines a series of indirect thought suppression techniques and therapies that have been explored for their efficacy as remedies for unwanted thoughts of all kinds and that offer some potential as means for effective suppression. the strategies that have some promise include focused distraction, stress and loa ...201122082381
heart rate variability as a marker of self-regulation.self-regulation is central to many of the most important individual and societal problems today. we sought to determine whether the relationship between self-regulation and heart rate variability (hrv) could be replicated and extended. we hypothesized that baseline hrv would predict persistence on an anagram task, and that under conditions requiring greater self-control, hrv would increase. two groups were given the same set of difficult and unsolvable anagrams. to induce self-regulatory fatigue ...201121739294
differences in mercury bioaccumulation between polar bears (ursus maritimus) from the canadian high- and sub-arctic.polar bears (ursus maritimus) are being impacted by climate change and increased exposure to pollutants throughout their northern circumpolar range. in this study, we quantified concentrations of total mercury (thg) in the hair of polar bears from canadian high- (southern beaufort sea, sbs) and sub- (western hudson bay, whb) arctic populations. concentrations of thg in polar bears from the sbs population (14.8 ± 6.6 μg g(-1)) were significantly higher than in polar bears from whb (4.1 ± 1.0 μg g ...201121678897
polar bear population status in the northern beaufort sea, canada, 1971-2006.polar bears (ursus maritimus) of the northern beaufort sea (nb) population occur on the perimeter of the polar basin adjacent to the northwestern islands of the canadian arctic archipelago. sea ice converges on the islands through most of the year. we used open-population capture-recapture models to estimate population size and vital rates of polar bears between 1971 and 2006 to: (1) assess relationships between survival, sex and age, and time period; (2) evaluate the long-term importance of sea ...201121639050
exposure to mixtures of organohalogen contaminants and associative interactions with thyroid hormones in east greenland polar bears (ursus maritimus).we investigated the multivariate relationships between adipose tissue residue levels of 48 individual organohalogen contaminants (ohcs) and circulating thyroid hormone (th) levels in polar bears (ursus maritimus) from east greenland (1999-2001, n=62), using projection to latent structure (pls) regression for four groupings of polar bears; subadults (suba), adult females with cubs (adf_n), adult females without cubs (adf_s) and adult males (adm). in the resulting significant pls models for suba, ...201121345491
predicting climate change impacts on polar bear litter size.predicting the ecological impacts of climate warming is critical for species conservation. incorporating future warming into population models, however, is challenging because reproduction and survival cannot be measured for yet unobserved environmental conditions. in this study, we use mechanistic energy budget models and data obtainable under current conditions to predict polar bear litter size under future conditions. in western hudson bay, we predict climate warming-induced litter size decli ...201121304515
spore series winner. penguins and polar bears integrates science and literacy. 201121273478
serum corticosteroid binding globulin expression is modulated by fasting in polar bears (ursus maritimus).polar bears (ursus maritimus) from several subpopulations undergo extended fasting during the ice-free season. however, the animals appear to conserve protein despite the prolonged fasting, though the mechanisms involved are poorly understood. we hypothesized that elevated concentrations of corticosteroid binding globulin (cbg), the primary cortisol binding protein in circulation, lead to cortisol resistance and provide a mechanism for protein conservation during extended fasting. the metabolic ...201120883811
flame retardants and legacy contaminants in polar bears from alaska, canada, east greenland and svalbard, 2005-2008.flame retardants and legacy contaminants were analyzed in adipose tissue from 11 circumpolar polar bear (ursus maritimus) subpopulations in 2005-2008 spanning alaska east to svalbard. although 37 polybrominated diphenyl ethers (pbdes), total-(α)-hexabromocyclododecane (hbcd), 2 polybrominated biphenyls (pbbs), pentabromotoluene, pentabromoethylbenzene, hexabromobenzene, 1,2-bis(2,4,6-tribromophenoxy(ethane) and decabromodiphenyl ethane were screened, only 4 pbdes, total-(α-)hbcd and bb153 were c ...201121131049
distribution of vitamins a (retinol) and e (α-tocopherol) in polar bear kidney: implications for biomarker studies.vitamins a and e content of inner organs, among these the kidneys, are increasingly being used as an indicator of adverse effects caused to the organism by e.g. environmental contaminants. in general, only a renal sub sample is used for analyses, and it is thus essential to know which part of the organ to sample in order to get a representative value for this important biomarker. the aim here was to assess the distribution of vitamins a (retinol) and e (α-tocopherol) within the polar bear multir ...201121696805
spatial and temporal trends of selected trace elements in liver tissue from polar bears (ursus maritimus) from alaska, canada and greenland.spatial trends and comparative changes in time of selected trace elements were studied in liver tissue from polar bears from ten different subpopulation locations in alaska, canadian arctic and east greenland. for nine of the trace elements (as, cd, cu, hg, mn, pb, rb, se and zn) spatial trends were investigated in 136 specimens sampled during 2005-2008 from bears from these ten subpopulations. concentrations of hg, se and as were highest in the (northern and southern) beaufort sea area and lowe ...201121687839
a randomized comparison of manual versus mechanical thrombus removal in primary percutaneous coronary intervention in the treatment of st-segment elevation myocardial infarction (treat-mi).the objective of this study was to compare the efficacy and long-term clinical outcome of manual thrombus aspiration with the export catheter (medtronic, minneapolis, mn) versus mechanical thrombus cutting/aspiration with the x-sizer system (ev3, white bear lake, mn) in primary percutaneous coronary intervention (ppci).201121681888
global warming: polar bears and people--implications for public health preparedness and disaster medicine: a call to action. 201118557288
antebrachial fractures in four captive polar bears (ursus maritimus).to identify common risk factors for antebrachial fractures of captive polar bears and to evaluate outcome after fracture repair.201116212591
mercury speciation in brain tissue of polar bears (ursus maritimus) from the canadian arctic.methylmercury (mehg) is a neurotoxicant that has been found at elevated concentrations in the arctic ecosystem. little is known about its internal dose in wildlife such as polar bears. we measured concentrations of mercury (hg) in three different brain regions (cerebellum, frontal lobe and brain stem) of 24 polar bears collected from the nunavik, canada between 2000 and 2003. speciation of hg was measured by high performance liquid chromatography coupled to inductively coupled plasma mass spectr ...201222406289
a neuroanatomical model of prefrontal inhibitory modulation of memory retrieval.memory of past experience is essential for guiding goal-related behavior. being able to control accessibility of memory through modulation of retrieval enables humans to flexibly adapt to their environment. understanding the specific neural pathways of how this control is achieved has largely eluded cognitive neuroscience. accordingly, in the current paper i review literature that examines the overt control over retrieval in order to reduce accessibility. i first introduce three hypotheses of in ...201222374224
white bear everywhere: exploring the boundaries of the attentional white bear phenomenon.some failures of selective attention may be explained by the attentional white bear (awb) phenomenon tsal & makovski (journal of experimental psychology: human perception and performance 32:351-363, 2006), which indicates that prior knowledge of a distractor location causes attention to be actively allocated to it. the awb effect is demonstrated in a task that includes infrequent trials that involve two simultaneous dots embedded among flanker trials. the dot positioned at an expected distractor ...201222323061
pcbs and oh-pcbs in polar bear mother-cub pairs: a comparative study based on plasma levels in 1998 and 2008.the aim of this study was to examine the plasma concentrations and prevalence of polychlorinated biphenyls (pcbs) and hydroxylated pcb-metabolites (oh-pcbs) in polar bear (ursus maritimus) mothers (n=26) and their 4 months old cubs-of-the-year (n=38) from svalbard to gain insight into the mother-cub transfer, biotransformation and to evaluate the health risk associated with the exposure to these contaminants. as samplings were performed in 1997/1998 and 2008, we further investigated the differen ...201222264925
thought suppression is associated with psychological distress in homebound older adults.engaging in thought suppression as a coping mechanism has been associated with higher rates of anxiety and depressive disorders in younger adults. homebound older adults are a population of elders experiencing poor health and high levels of depression and anxiety. it is unclear the extent to which psychological factors, such as thought suppression, are associated with distress, given that their health and disability status may be more salient. the aim of this study was to investigate thought sup ...201222170756
perseverative negative cognitive processes are associated with depression in people with long-term conditions.perseverative negative cognitive processes, such as worry, suppression and avoidance of undesirable thoughts, have been linked to persistence and relapse of depression. such processes could account for poor treatment response though they have received little research attention in people with long-term conditions (ltcs).201222169527
relations between childhood traumatic experiences, dissociation, and cognitive models in obsessive compulsive disorder.previous studies have indicated that obsessive compulsive disorder (ocd) is associated with childhood traumatic experiences and higher levels of dissociation. dissociative tendency may arise when individual attempt to incorporate adverse experiences into cognitive schema.201222122656
temporal trend of mercury in polar bears (ursus maritimus) from svalbard using teeth as a biomonitoring tissue.we examined the use of mercury (hg) and nitrogen and carbon stable isotopes in teeth of polar bear (ursus maritimus) from svalbard as biotracers of temporal changes in hg pollution exposure between 1964 and 2003. teeth were regarded as a good matrix of the hg exposure, and in total 87 teeth of polar bears were analysed. dental hg levels ranged from 0.6 to 72.3 ng g(-1) dry weight and increased with age during the first 10 years of life. a decreasing time trend in hg concentrations was observed o ...201222113146
measuring environmental stress in east greenland polar bears, 1892-1927 and 1988-2009: what does hair cortisol tell us?hair sampled from 96 east greenland polar bears (ursus maritimus) over the periods 1892-1927 and 1988-2009 was analyzed for cortisol as a proxy to investigate temporal patterns of environmental stress. cortisol concentration was independent of sex and age, and was found at significantly higher (p<0.001) concentrations in historical hair samples (1892-1927; n=8) relative to recent ones (1988-2009; n=88). in addition, there was a linear time trend in cortisol concentration of the recent samples (p ...201222572112
non-invasive detection of candidate pregnancy protein biomarkers in the feces of captive polar bears (ursus maritimus).currently, there is no method of accurately and non-invasively diagnosing pregnancy in polar bears. specific proteins may exhibit altered profiles in the feces of pregnant bears, but predicting appropriate candidate proteins to investigate is speculative at best. the objective of this study was to identify potential pregnancy biomarker proteins based on their increased abundance in the feces of pregnant polar bears compared to pseudopregnant females (controls) using two-dimensional in-gel electr ...201222538002
lactational transfer of mercury and polychlorinated biphenyls in polar bears.we examined concentrations of total mercury (thg, inorganic and methylated forms) and polychlorinated biphenyls (pcbs) in blood and milk from free-ranging southern beaufort-chukchi sea polar bears (ursus maritimus) to assess maternal transfer of contaminants during lactation and the potential health risk to nursing young. concentrations of contaminants in the blood of dependent and juvenile animals (ages 1-5 years) ranged from 35.9 to 52.2 μg kg(-1) ww for thg and 13.9 to 52.2 μg kg(-1) ww (3255 ...201222464860
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
mama grizzly and the polar bears. 201222653483
plastics in the marine environment: the dark side of a modern gift.plastics are cheap, strong, and durable and offer considerable benefits to humanity. they potentially can enhance the benefits that both medical and scientific technology will bestow to humankind. however, it has now been several decades since the use of plastics exploded, and we have evidence that our current approach to production, use, transport and disposal of plastic materials has caused, and is still causing serious effects on wildlife, and is not sustainable. because of frequent inappropr ...201222610295
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
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
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