Publications

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linear and branched perfluorooctane sulfonate isomers in technical product and environmental samples by in-port derivatization-gas chromatography-mass spectrometry.perfluorooctane sulfonate (pfos) is found globally as an environmental contaminant and is highly bioaccumulative in exposed biota including humans. however, there is a dearth of environmental information on the isomeric profile of pfos, especially in biological samples, which requires suitable analysis methods for the identification and quantification of ultratrace amounts. in the present study, a novel method was developed that incorporates clean up by solid-phase extraction (spe) wax cartridge ...200919402680
estimated dietary exposure to fluorinated compounds from traditional foods among inuit in nunavut, canada.increasing evidence shows that persistent organic pollutants such as perfluorinated compounds (pfcs) are found in the arctic ecosystem and their prevalence is causing human health concerns. the objective of this study was to estimate dietary exposure to pfcs among inuit in northern canada. perfluorooctane sulfonate (pfos), perfluorinated carboxylates (pfca c(7)-c(11)) and fluorotelomer unsaturated carboxylic acids (6:2, 8:2 and 10:2 ftuca) were measured in 68 traditional foods collected in nunav ...200919342075
implications of climate change for northern canada: freshwater, marine, and terrestrial ecosystems.climate variability and change is projected to have significant effects on the physical, chemical, and biological components of northern canadian marine, terrestrial, and freshwater systems. as the climate continues to change, there will be consequences for biodiversity shifts and for the ranges and distribution of many species with resulting effects on availability, accessibility, and quality of resources upon which human populations rely. this will have implications for the protection and mana ...200919714961
dietary, age and trans-generational effects on the fate of organohalogen contaminants in captive sledge dogs in greenland.studies on the fate of organohalogen contaminants (ohcs) in wild top predator mammals in the arctic have often been a challenge due to important knowledge deficiencies in the life history of the sampled animals. the present study investigated the influence of age, dietary and trans-generational factors on the fate of major lipophilic chlorinated and brominated ohcs in adipose tissue of a potential surrogate captive species for the polar bear (ursus maritimus), the sledge dog (canis familiaris) i ...200918774608
acquired umbilical hernias in four captive polar bears (ursus maritimus).umbilical hernias are a common occurrence in domestic animals and humans but have not been well documented in polar bears. surgical reduction and herniorrhaphies were performed to correct acquired hernias in the region of the umbilicus in four adult captive polar bears (ursus maritimus) housed in north american zoos. two of the four bears were clinically unaffected by their hernias prior to surgery. one bear showed signs of severe discomfort following acute enlargement of the hernia. in another ...200920063824
anatomy of the white bear suppression inventory (wbsi): a review of previous findings and a new approach.the white bear suppression inventory (wbsi; wegner & zanakos, 1994) was originally designed to assess people's inclination toward thought suppression. in this article, we provide a detailed review of previous findings on the structure of this instrument and present a study that took a new statistical approach. it involved an exploratory factor analysis of the french wbsi using the weighted least squares mean and variance estimator as well as parametric item response theory analyses. results clea ...200920017061
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
sea ice-associated diet change increases the levels of chlorinated and brominated contaminants in polar bears.two global environmental issues, climate change and contamination by persistent organic pollutants, represent major concerns for arctic ecosystems. yet, it is unclear how these two stressors interact in the arctic. for instance, the influence of climate-associated changes in food web structure on exposure to pollutants within arctic ecosystems is presently unknown. here, we report on recent changes in feeding ecology (1991-2007) in polar bears (ursus maritimus) from the western hudson bay subpop ...200919603643
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
thought suppression failures in combat ptsd: a cognitive load hypothesis.the present study investigated the relation between thought suppression of emotionally neutral content [i.e., wegner's (1994) "white bear"], incidental traumatic thought intrusion, and skin conductance responses in combat-related posttraumatic stress disorder (ptsd). participants included service members who either: a) had ptsd following an operation iraqi freedom deployment; b) were free of psychiatric diagnosis following deployment (combat equivalent), or c) were pre-deployed and without psych ...200919586619
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
bionics in textiles: flexible and translucent thermal insulations for solar thermal applications.solar thermal collectors used at present consist of rigid and heavy materials, which are the reasons for their immobility. based on the solar function of polar bear fur and skin, new collector systems are in development, which are flexible and mobile. the developed transparent heat insulation material consists of a spacer textile based on translucent polymer fibres coated with transparent silicone rubber. for incident light of the visible spectrum the system is translucent, but impermeable for u ...200919376769
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
variation in visitor perceptions of a polar bear enclosure based on the presence of natural vs. un-natural enrichment items.a debate exists among modern zoo staff as to whether or not the addition of un-naturalistic enrichment takes away from, or even defeats, the educational messages designers are trying to incorporate in naturalistic exhibits. a visitor study was conducted at the central park zoo's polar bear exhibit in order to determine whether or not the type of enrichment in an enclosure actually alters guest perceptions. visitors were exposed to one of two enrichment treatments in the bear enclosure: naturalis ...200919681144
polar bear trackingvia satellite. 2009687726
[group infection with trichinella from the meat of a polar bear in the soviet arctic region]. 200913450973
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
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
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
the experience of intrusions scale: a preliminary examination.intrusive thoughts (i.e., unwelcome, distressing, involuntary thoughts) are prevalent in a variety of clinical conditions and are increasingly a focus of translational research. the goal of this study was to develop and preliminarily examine a brief self-report measure designed to assess clinically relevant aspects of the experience of intrusive thoughts related to a particular target. the experience of intrusions scale (eis) is a five-item measure that assesses the frequency, unpredictability, ...200918937103
organohalogen concentrations in blood and adipose tissue of southern beaufort sea polar bears.we analyzed 151 organohalogen chemicals (ohcs) in whole blood and subcutaneous fat of 57 polar bears sampled along the alaskan beaufort sea coast in spring, 2003. all major organochlorine pesticides, pcbs, pbdes and their congeners were assessed. concentrations of most ohcs continue to be lower among southern beaufort sea polar bears than reported for other populations. additionally, toxaphenes and related compounds were assessed in adipose tissue, and 8 perflourinated compounds (pfcs) were exam ...200818775556
thought suppression in obese and non-obese restrained eaters: piece of cake or forbidden fruit?this article examines thought suppression tendencies in restrained eaters. furthermore, the dynamics between failing thought suppression and thought control strategies are explored.200818074330
successful removal of a ruptured silastic percutaneous central venous catheter in a tiny premature infant.the spontaneous rupture of a silastic catheter is a rare occurrence. we describe our experience of managing a tiny premature infant with embolization of a silastic percutaneous central venous catheter (pcvc) and discuss the possible mechanisms of the embolization. a 28-week, 980 g, preterm male infant received a silastic pcvc (epicutaneo cava catheter, vygon, germany) for parenteral nutritional support at 4 days of age. the catheter was introduced percutaneously and advanced without difficulty t ...200817302225
structural validity and reliability of the spanish version of the white bear suppression inventory (wbsi) in a sample of the general spanish population.this paper introduces the validation of the spanish adaptation of the white bear suppression inventory (wbsi) by wegner and zanakos (1994). a sample of 833 people from the general population completed the wbsi along with other questionnaires. the exploratory factor analysis and the confirmatory factor analysis supported a two-factor solution accounting for 51.8% of the cumulative variance. this structure is comprised of the two following factors: unwanted intrusive thoughts (alpha = .87, r = .70 ...200818988450
polar bear numbers set to fall. 200818497777
climate change. polar bear listing opens door to new lawsuits. 200818497267
effects of climate change on polar bears.in this article, we review the effects on polar bears of global warming that have already been observed, and try to evaluate what may happen to the polar bears in the future. many researchers have predicted a wide range of impacts of climate change on polar bear demography and conditions. a predicted major reduction in sea ice habitat will reduce the availability of ice associated seals, the main prey of polar bears, and a loss and fragmentation of polar bear habitat will ultimately lead to larg ...200818717367
modelling the mating system of polar bears: a mechanistic approach to the allee effect.allee effects may render exploited animal populations extinction prone, but empirical data are often lacking to describe the circumstances leading to an allee effect. arbitrary assumptions regarding allee effects could lead to erroneous management decisions so that predictive modelling approaches are needed that identify the circumstances leading to an allee effect before such a scenario occurs. we present a predictive approach of allee effects for polar bears where low population densities, an ...200818029307
dreaming of white bears: the return of the suppressed at sleep onset.the present study examined the effects of thought suppression on sleep-onset mentation. it was hypothesized that the decrease of attentional control in the transition to sleep would lead to a rebound of a suppressed thought in hypnagogic mentation. twenty-four young adults spent two consecutive nights in a sleep laboratory. half of the participants were instructed to suppress a target thought, whereas the other half freely thought of anything at all. to assess target thought frequency, three dif ...200817981054
polar bears (ursus maritimus), the most evolutionary advanced hibernators, avoid significant bone loss during hibernation.some hibernating animals are known to reduce muscle and bone loss associated with mechanical unloading during prolonged immobilisation,compared to humans. however, here we show that wild pregnant polar bears (ursus maritimus) are the first known animals to avoid significant bone loss altogether, despite six months of continuous hibernation. using serum biochemical markers of bone turnover, we showed that concentrations for bone resorption are not significantly increased as a consequence of hiber ...200818249018
a false killer whale adjusts its hearing when it echolocates.the use of auditory evoked potential (aep) measurements has added considerably to knowledge of the hearing mechanisms of marine mammals. we have recently measured the hearing of a stranded infant risso's dolphin, the audiograms of white-beaked dolphins temporarily caught and released, and the hearing of anaesthetized polar bears. most small toothed whales echolocate and hear very high frequency sounds underwater. while much has previously been learned about the echolocation performance and chara ...200818490386
quantifying the sensitivity of arctic marine mammals to climate-induced habitat change.we review seven arctic and four subarctic marine mammal species, their habitat requirements, and evidence for biological and demographic responses to climate change. we then describe a pan-arctic quantitative index of species sensitivity to climate change based on population size, geographic range, habitat specificity, diet diversity, migration, site fidelity, sensitivity to changes in sea ice, sensitivity to changes in the trophic web, and maximum population growth potential (r(max)). the index ...200818494365
virtual cranial endocast of the oldest giant panda (ailuropoda microta) reveals great similarity to that of its extant relative.recent development of computed tomography and three-dimensional visualization techniques has enabled the non-destructive inspection of the endocast morphology of fossil neurocranium, the basic material for paleoneurological study. a virtual cranial endocast was reconstructed based on the first skull of the oldest giant panda, ailuropoda microta, discovered recently and dated at more than 2 myr (million years) ago. it was compared with that of the extant giant panda (a. melanoleuca) and that of t ...200818600311
geographic distribution of selected elements in the livers of polar bears from greenland, canada and the united states.to assess geographic distributions of elements in the arctic we compared essential and non-essential elements in the livers of polar bears (ursus maritimus) collected from five regions within canada in 2002, in alaska between 1994 and 1999 and from the northwest and east coasts of greenland between 1988 and 2000. as, hg, pb and se varied with age, and co and zn with gender, which limited spatial comparisons across all populations to cd, which was highest in greenland bears. collectively, geograp ...200817959286
new hosts for equine herpesvirus 9.equine herpesvirus 9 was detected in a polar bear with progressive encephalitis; the source was traced to 2 members of a potential equid reservoir species, grevy's zebras. the virus was also found in an aborted persian onager. thus, the natural host range is extended to 6 species in 3 mammalian orders.200818826828
mitochondrial genomes reveal an explosive radiation of extinct and extant bears near the miocene-pliocene boundary.despite being one of the most studied families within the carnivora, the phylogenetic relationships among the members of the bear family (ursidae) have long remained unclear. widely divergent topologies have been suggested based on various data sets and methods.200818662376
monorail snare technique for the retrieval of an adherent microcatheter from an onyx cast: technical case report.microcatheters retained after onyx (ev3 neurovascular, inc., irvine, ca) embolization represent a potential source of thromboembolic complications. catheter retention depends on the degree of onyx reflux and vessel tortuosity. to overcome this problem, we have adapted a previously described monorail snare technique for stretched coils to remove an adherent microcatheter from the occipital artery during onyx embolization of a dural arteriovenous fistula.200818728613
greenland sledge dogs (canis familiaris) develop liver lesions when exposed to a chronic and dietary low dose of an environmental organohalogen cocktail.we assessed the relationship between exposure to organohalogen polluted minke whale (balaenoptera acutorostrata) blubber and liver morphology and function in a generational controlled study of 28 greenland sledge dogs (canis familiaris). the prevalence of portal fibrosis, mild bile duct hyperplasia, and vascular leukocyte infiltrations was significantly higher in the exposed group (all chi-square: p<0.05). in case of granulomas, the frequency was significantly highest in the bitches (p generatio ...200817904542
novel papillomavirus isolated from the oral mucosa of a polar bear does not cluster with other papillomaviruses of carnivores.papillomatosis has been documented in several carnivores, and papillomavirus (pv) types have been characterized from lesions in a number of carnivore species: the canine oral pv (copv), the felis domesticus pv type 1 (fdpv-1) isolated from a persian cat, the procyon lotor pv type 1 (plpv-1) isolated from a raccoon, the canine pv type 2 (cpv-2) from a dog's foot pad lesion and the canine pv type 3 (cpv-3) associated with a canine epidermodysplasia verruciformis - like disease. a tissue sample was ...200818215475
deciphering the complete mitochondrial genome and phylogeny of the extinct cave bear in the paleolithic painted cave of chauvet.retrieving a large amount of genetic information from extinct species was demonstrated feasible, but complete mitochondrial genome sequences have only been deciphered for the moa, a bird that became extinct a few hundred years ago, and for pleistocene species, such as the woolly mammoth and the mastodon, both of which could be studied from animals embedded in permafrost. to enlarge the diversity of mitochondrial genomes available for pleistocene species, we turned to the cave bear (ursus spelaeu ...200818955696
occurrence and prevalence of clostridium perfringens in polar bears from svalbard, norway.to obtain insight into the occurrence and prevalence of clostridium perfringens and its major toxins in polar bears (ursus maritimus), we took fecal samples for bacteriologic analysis from live-captured bears in the svalbard archipelago, norway, in 2001. clostridium perfringens was isolated from 40 of 92 samples (44%). thirty strains were further characterized by determining toxin type and were classified to be type a, while one was also positive for the gene encoding beta2-toxin. despite the fa ...200818263831
target tissue selectivity and burdens of diverse classes of brominated and chlorinated contaminants in polar bears (ursus maritimus) from east greenland.the tissue-specific composition of sum classes of brominated and chlorinated contaminants and metabolic/degradation byproducts was determined in adult male and female polar bears from east greenland. significantly (p < 0.05) higher concentrations of sigma-pcbs, various other organochlorines such as sigma-chl, p,p'-dde, sigma-cbz, sigma-hchs, octachlorostyrene (ocs), sigma-mirex, dieldrin, the flame retardants sigma-pbdes, and total-(alpha)-hexabromocyclododecane (hbcd), sigma-methylsulfonyl (mes ...200818323098
regional variability in food availability for arctic marine mammals.this review provides an overview of prey preferences of seven core arctic marine mammal species (amm) and four non-core species on a pan-arctic scale with regional examples. arctic marine mammal species exploit prey resources close to the sea ice, in the water column, and at the sea floor, including lipid-rich pelagic and benthic crustaceans and pelagic and ice-associated schooling fishes such as capelin and arctic cod. prey preferred by individual species range from cephalopods and benthic biva ...200818494364
arctic marine mammals and climate change: impacts and resilience.evolutionary selection has refined the life histories of seven species (three cetacean [narwhal, beluga, and bowhead whales], three pinniped [walrus, ringed, and bearded seals], and the polar bear) to spatial and temporal domains influenced by the seasonal extremes and variability of sea ice, temperature, and day length that define the arctic. recent changes in arctic climate may challenge the adaptive capability of these species. nine other species (five cetacean [fin, humpback, minke, gray, an ...200818494369
does the nutrition profile of vitamins, fatty acids and microelements counteract the negative impact from organohalogen pollutants on bone mineral density in greenland sledge dogs (canis familiaris)?there is a great need for understanding the impact from dietary ohcs (organohalogen compounds) on bone mineral composition - and thereby osteoporosis - in especially arctic wildlife such as polar bears (ursus maritimus) as well as humans. for that purpose, we measured bmd (bone mineral density) by dxa scanning (g/cm(-2)) in 15 age and weight normalized sledge dog (canis familiaris) bitches and their 26 pups divided into a control group (n=26) given 50-200 g/day clean pork (suis scrofa) fat and a ...200818342937
tissue-specific congener composition of organohalogen and metabolite contaminants in east greenland polar bears (ursus maritimus).congener patterns of the major organohalogen contaminant classes of pcbs, pbdes and their metabolites and/or by-products (oh-pcbs, meso2-pcbs, oh-pbdes and meo-pbdes) were examined in adipose tissue, liver, brain and blood of east greenland polar bears (ursus maritimus). pcb, oh-pcb, meso2-pcb and pbde congener patterns showed significant differences (p<or=0.05) mainly in the liver and the brain relative to the adipose tissue and the blood. oh-pbdes and meo-pbdes were not detected in the brain a ...200817707109
increasing perfluoroalkyl contaminants in east greenland polar bears (ursus maritimus): a new toxic threat to the arctic bears.a well-defined subsample of 128 subadult (3-5 years) polar bears (ursus maritimus) from 19 sampling years within the period 1984-2006 was investigated for perfluoroalkyl contaminants (pfcs). linear regression analysis of logarithmic-transformed median concentrations showed significant annual increases for pfos (4.7%), pfna (6.1%), pfuna (5.9%), pfda (4.3%), pftra (8.5%), pfoa (2.3%), and pfdoa (5.2%). for four of the pfcs, a loess smoother model provided significantly better descriptions, reveal ...200818505019
in search of virus carriers of the 1988 and 2002 phocine distemper virus outbreaks in european harbour seals.european harbour seal (phoca vitulina) populations decreased substantially during the phocine distemper virus (pdv) outbreaks of 1988 and 2002. different hypotheses have stated that various seals and terrestrial carnivore species might be the source of infection. to further analyse these hypotheses, grey (halichoerus grypus) and ringed (phoca hispida) seals, polar bears (ursus maritimus) and minks (mustela lutreola) were sampled from the north sea and east greenland coasts between 1988 and 2004 ...200817896075
the evolution of arctic marine mammals.this review deals only with the evolutionary history of core arctic marine mammals: polar bear (ursus maritimus), walrus (odobenus rosmarus), bearded seal (erignathus barbatus), harp seal (pagophilus groenlandica), ringed seal (phoca hispida), bowhead whale (balaena mysticetus), white whale (delphinapterus leucas), and narwhal (monodon monoceras). sections on the evolutionary background of pinnipeds and whales help to provide a better perspective on these core species. polar bears stemmed from b ...200818494361
comparative fate of organohalogen contaminants in two top carnivores in greenland: captive sledge dogs and wild polar bears.the limited knowledge and/or the inability to control physiological condition parameters that influence the fate of organohalogen contaminants (ohcs) has been the foremost confounding aspect in monitoring programs and health risk assessments of wild top predators in the arctic such as the polar bear (ursus maritimus). in the present comparative study, we used a potential surrogate canoidea species for the east greenland polar bear, the captive sledge dog (canis familiaris), to investigate some f ...200818248775
analysis of complete mitochondrial genome sequences increases phylogenetic resolution of bears (ursidae), a mammalian family that experienced rapid speciation.despite the small number of ursid species, bear phylogeny has long been a focus of study due to their conservation value, as all bear genera have been classified as endangered at either the species or subspecies level. the ursidae family represents a typical example of rapid evolutionary radiation. previous analyses with a single mitochondrial (mt) gene or a small number of mt genes either provide weak support or a large unresolved polytomy for ursids. we revisit the contentious relationships wi ...200717956639
age and seasonal variability of polybrominated diphenyl ethers in free-ranging east greenland polar bears (ursus maritimus).polybrominated diphenyl ethers (pbdes) were analysed in adipose tissue from 92 east greenland polar bears (ursus maritimus) sampled during 1999-2001. mean sigmapbde concentrations were 70 ng/g lipid weight (lw) (range: 22-192 ng/g lw) and showed no relationship with age or sex. of the 32 analysed pbde congeners; bde47, bde153, bde99 and bde100 dominated, and comprised 99.6% of the sigmapbde concentration. the sigmapbde concentration had a highly significant correlation with sigmapcb, sigmachl, d ...200717055135
the complete mitochondrial genome and phylogenetic analysis of the giant panda (ailuropoda melanoleuca).the complete mitochondrial genome sequence of the giant panda, ailuropoda melanoleuca, was determined by the long and accurate polymerase chain reaction (la-pcr) with conserved primers and primer walking sequence methods. the complete mitochondrial dna is 16,805 nucleotides in length and contains two ribosomal rna genes, 13 protein-coding genes, 22 transfer rna genes and one control region. the total length of the 13 protein-coding genes is longer than the american black bear, brown bear and pol ...200717499457
spatial and temporal variation in size of polar bear (ursus maritimus) sexual organs and its use in pollution and climate change studies.sexual organs and their development are susceptible to atmospheric transported environmental xenoendocrine pollutants and climate change (food availability). we therefore investigated sexual organs from 55 male and 44 female east greenland polar bears (ursus maritimus) to obtain information about growth/size and sexual maturity. then, the genitalia size was compared with those previously reported from canadian and svalbard polar bears. growth models showed that east greenland male polar bears re ...200717720226
accumulation and transfer of contaminants in killer whales (orcinus orca) from norway: indications for contaminant metabolism.blubber tissue of one subadult and eight male adult killer whales was sampled in northern norway in order to assess the degree and type of contaminant exposure and transfer in the herring-killer whale link of the marine food web. a comprehensive selection of contaminants was targeted, with special attention to toxaphenes and polybrominated diphenyl ethers (pbdes). in addition to assessing exposure and food chain transfer, selective accumulation and metabolism issues also were addressed. average ...200717702329
development and application of an ultratrace method for speciation of organotin compounds in cryogenically archived and homogenized biological materials.an accurate, ultra-sensitive and robust method for speciation of mono, di, and tributyltin (mbt, dbt, and tbt) by speciated isotope-dilution gas chromatography-inductively coupled plasma-mass spectrometry (sid-gc-icpms) has been developed for quantification of butyltin concentrations in cryogenic biological materials maintained in an uninterrupted cryo-chain from storage conditions through homogenization and bottling. the method significantly reduces the detection limits, to the low pg g(-1) lev ...200717287930
positive selection in the n-terminal extramembrane domain of lung surfactant protein c (sp-c) in marine mammals.maximum-likelihood models of codon and amino acid substitution were used to analyze the lung-specific surfactant protein c (sp-c) from terrestrial, semi-aquatic, and diving mammals to identify lineages and amino acid sites under positive selection. site models used the nonsynonymous/synonymous rate ratio (omega) as an indicator of selection pressure. mechanistic models used physicochemical distances between amino acid substitutions to specify nonsynonymous substitution rates. site models strongl ...200717568982
skull pathology in east greenland and svalbard polar bears (ursus maritimus) during 1892 to 2002 in relation to organochlorine pollution.east greenland and svalbard polar bears (ursus maritimus) are heavily polluted with long-range transported organochlorines such as pcbs (polychlorinated biphenyls). to investigate the negative health impacts, a time-trend study of skull pathology was conducted on 269 east greenland and 241 svalbard polar bears. the skulls were sampled during 1892-2002 and 1964-1992, respectively. seven different pathological changes were found: adonti, displacement of teeth, caries, osseous proliferations, exost ...200717156821
vitamin a-storing cells (stellate cells).hepatic stellate cells (hscs; also called as vitamin a-storing cells, lipocytes, interstitial cells, fat-storing cells, ito cells) exist in the space between parenchymal cells and sinusoidal endothelial cells of the hepatic lobule, and store 80% of vitamin a in the whole body as retinyl palmitate in lipid droplets in the cytoplasm. in physiological conditions, these cells play pivotal roles in the regulation of vitamin a homeostasis; they express specific receptors for retinol-binding protein (r ...200717368315
variation in digestive efficiency of captive north american river otters (lontra canadensis) on various diets.energy content, proximate nutrient values, passage rate, and digestive efficiency associated with various diet types and factors affecting these parameters have not been quantified for the north american river otter (lontra canadensis). we measured energy digestive efficiency (deff) and intestinal passage rate of three captive river otters on their regular diet (a combination of polar bear diet, cat food, and feline diet) and on test diets consisting of the constituent components of their regula ...200719360560
are liver and renal lesions in east greenland polar bears (ursus maritimus) associated with high mercury levels?in the arctic, polar bears (ursus maritimus) bio-accumulate mercury as they prey on polluted ringed seals (phoca hispida) and bearded seals (erignathus barbatus). studies have shown that polar bears from east greenland are among the most mercury polluted species in the arctic. it is unknown whether these levels are toxic to liver and kidney tissue.200717439647
occurrence of hydroxylated polychlorinated biphenyls in the brain of cetaceans stranded along the japanese coast.levels of hydroxylated polychlorinated biphenyls (oh-pcbs) and pcbs were measured in the brain of melon-headed whales (mw: peponocephala electra), striped dolphins (sd: stenella coeruleoalba) and finless porpoises (fp: neophocaena phocaenoides) stranded along the japanese coast during 2002-2003. levels of oh-pcbs (including identified and unknown oh-p(5)cb, -h(6)cb, -h(7)cb and o(8)cb congeners) in the brain of mw, sd and fp were in the range of 20-290, 21-330 and 170-240pg/g wet wt., respective ...200717445835
contaminants, diet, plasma fatty acids and smoking in greenland 1999-2005.the purpose of this study is to monitor and assess human exposure to pollution in the arctic which presents a potential future health risk for the local populations. epidemiological studies in greenland have shown that human blood levels of several organic contaminants are very high, especially in the north where people depend on local food. in east greenland (ittoqqortoormiit (scoresbysund)) the population shows the highest blood levels of several persistent organic pollutants found in arctic c ...200717157358
influence of the temperature gradient in blubber on the bioaccumulation of persistent lipophilic organic chemicals in seals.seals constitute an important link in food webs of the arctic environment and are an important vector of persistent lipophilic organic pollutants to top predators (e.g., polar bears) and humans. two fugacity-based, non-steady state, mechanistic lifetime models were assembled to explore the influence of the temperature gradient in the insulating blubber on the distribution and bioaccumulation of persistent lipophilic organic pollutants in seals. the behavior of a two-compartment model that distin ...200717702331
sea ice occurrence predicts genetic isolation in the arctic fox.unlike oceanic islands, the islands of the arctic sea are not completely isolated from migration by terrestrial vertebrates. the pack ice connects many arctic sea islands to the mainland during winter months. the arctic fox (alopex lagopus), which has a circumpolar distribution, populates numerous islands in the arctic sea. in this study, we used genetic data from 20 different populations, spanning the entire distribution of the arctic fox, to identify barriers to dispersal. specifically, we con ...200717868292
why did the white bear return? obsessive-compulsive symptoms and attributions for unsuccessful thought suppression.the current study examined the nature and consequences of attributions about unsuccessful thought suppression. undergraduate students with either high (n=67) or low (n=59) levels of obsessive-compulsive symptoms rated attributions to explain their unsuccessful thought suppression attempts. we expected that self-blaming attributions and attributions ascribing importance to unwanted thoughts would predict more distress and greater recurrence of thoughts during time spent monitoring or suppressing ...200717825786
investigation of the indulgence cycles hypothesis of suppression on experimentally induced visual intrusions in dysphoria.within the thought control literature, wegner [(1989). white bears and other unwanted thoughts: suppression, obsession, and the psychology of mental control. new york, ny, usa: penguin press.] referred to the combined initial suppression and expression phases of thought control as an indulgence cycle which results in the rebound effect typically observed in suppression studies. according to ironic process theory [wegner, (1994). ironic processes of mental control. psychological review, 101, 34-5 ...200717692285
working memory, control of interference and everyday experience of thought interference: when age makes the difference.a number of studies suggest that age differences in working memory may be attributed to age-related differences in inhibitory efficacy. nevertheless, little is known about the impact of intrusive thoughts, which occurs in everyday situations on working memory performance. this study investigates the role of cognitive and everyday inhibition mechanisms in working memory performance.200717607087
trace element concentrations in livers of polar bears from two populations in northern and western alaska.concentrations of 20 trace elements (v, cr, mn, co, cu, zn, rb, sr, mo, ag, cd, in, sn, sb, cs, ba, hg, tl, pb, and bi) were measured in livers of polar bears (ursus maritimus) collected from northern and western alaska from 1993 to 2002 to examine differences in the profiles of trace metals between the beaufort sea (northern alaska) and the chukchi sea (western alaska) subpopulations in alaska. among the trace elements analyzed, concentrations of cu (50-290 microg/g, dry wt) in polar bear liver ...200717571199
will polar bears be ok? 200717477159
25-oh-d(3), calcium, phosphorus, and alkaline phosphatase content in sera from captive polar bear (ursus maritimus) cubs at the denver zoological foundation.after the development of rickets in two hand-reared polar bear (ursus maritimus) cubs at the denver zoological foundation we initiated a project opportunistically evaluating sera 25-oh-d(3), calcium, phosphorus, and alkaline phosphatase levels in seven mother-reared polar bear cubs. from one to three serum samples were obtained while the cub was still in the den with no access to natural sunlight and one after the cub exited the den. the sera 25-oh-d(3) increased as the cubs grew (108+/-37 nmol/ ...200719360570
percutaneous retrieval of a chronic foreign body with both intravascular and extravascular components.removal of unwanted intravascular foreign body is a useful but infrequent procedure carried out by interventional radiologists. we study a patient who had a long guidewire left in her body following central venous catheter placement by a surgeon. the guidewire was later found in situ, with both intravascular and extravascular components in continuity. we successfully removed the guidewire without causing any complications. standard interventional techniques, amplatz gooseneck snare (microvena, w ...200717419867
polar bear ursus maritimus hearing measured with auditory evoked potentials.while there has been recent concern about the effects of sound on marine mammals, including polar bears, there are no data available measuring the hearing of any bear. the in-air hearing of three polar bears was measured using evoked auditory potentials obtained while tone pips were played to three individually anaesthetized bears at the kolmården djurpark. hearing was tested in half-octave steps from 1 to 22.5 khz. measurements were not obtainable at 1 khz and best sensitivity was found in the ...200717371910
are polar bears too polarizing? 200718075062
endangered species. u.s. weighs protection for polar bears. 200717204613
retrieval stent filter: treatment of budd chiari syndrome complicated with inferior vena cava thrombosis--initial clinical experience.the purpose of this study was to evaluate the initial clinical efficacy of a retrieval stent filter for the management of budd chiari syndrome complicated with inferior vena cava thrombosis.200717258004
the dependence of seasonal movements of female polar bears on the reproductive status. 200611605346
behavioral decisions for managing social distance and aggression in captive polar bears (ursus maritimus).the polar bear (ursus maritimus) in most zoos attracts high levels of public attention and can play an important role in conservation education. polar bears in the wild are typically solitary; bears in captivity often house socially. this study reported behavioral evidence on how bears manage this situation and whether proximity leads to aggression. the study recorded location and behavior once per minute for 106 hr for 2 female polar bears at the philadelphia zoo; the samples represented all ti ...200617112334
density functional theory for hard-sphere mixtures: the white bear version mark ii.in the spirit of the white bear version of fundamental measure theory we derive a new density functional for hard-sphere mixtures which is based on a recent mixture extension of the carnahan-starling equation of state. in addition to the capability to predict inhomogeneous density distributions very accurately, like the original white bear version, the new functional improves upon consistency with an exact scaled-particle theory relation in the case of the pure fluid. we examine consistency in d ...200621690897
composition of chlorinated hydrocarbon contaminants among major adipose tissue depots of polar bears (ursus maritimus) from the canadian high arctic.monitoring of environmental contaminants in canadian arctic polar bears (ursus maritimus) typically has used superficial adipose tissue samples collected as part of controlled native subsistence hunts. however, little attention has been paid to the compositional difference in contaminants that may exist among the major adipose depots that are routinely collected. to address this knowledge gap, we investigated the profiles and concentrations of chlorinated hydrocarbon contaminants (chcs), includi ...200616978684
suppression of neutral and trauma targets: implications for posttraumatic stress disorder.recent findings suggest that thought suppression may lead to increased intrusive thoughts for trauma survivors, paradoxically increasing symptoms. participants with trauma history, 31 with posttraumatic stress disorder (ptsd) and 34 without ptsd, engaged in neutral white bear and trauma suppression tasks. a group difference was found for the trauma task and not for the neutral task. for the trauma task, both groups demonstrated an increase of trauma thoughts during suppression, but the ptsd grou ...200616929506
a norwegian adaptation of the penn state worry questionnaire: factor structure, reliability, validity and norms.a norwegian version of the penn state worry questionnaire (pswq) was administered to 304 undergraduate students together with the beck depression inventory (bdi), the state-trait anxiety inventory (stai) and the maudsley obsessive compulsive inventory (moci). the pswq was also administered to a community sample comprising 879 subjects, together with the beck anxiety inventory (bai), the beck depression inventory ii (bdi ii) and the white bear suppression inventory (wbsi). structural equation mod ...200616869861
issues of choice and control in the behaviour of a pair of captive polar bears (ursus maritimus).stereotyped behaviour occurs in a wide variety of captive animals including ursids. the provision of animal control over aspects of their environment by providing choices is a critical element for improving welfare. the behaviour of two sibling polar bears at a metropolitan zoo was examined to investigate the effect of providing access to their indoor, off-exhibit holding space. both bears demonstrated behavioural changes when given the choice to access their indoor dens including decreased ster ...200616687218
the attentional white bear phenomenon: the mandatory allocation of attention to expected distractor locations.the authors devised a prestimulus-probe method to assess the allocation of attention as a function of participants' top-down expectancies concerning distractor and target locations. participants performed the flanker task, and distractor locations remained fixed. on some trials, instead of the flanker display, either 2 simultaneous dots or a horizontal line appeared. the dot in the expected distractor location was perceived to occur before the dot in the expected empty location, and the line app ...200616634675
temporal trends of perfluoroalkyl contaminants in polar bears (ursus maritimus) from two locations in the north american arctic, 1972-2002.perfluoroalkyl substances are globally distributed anthropogenic contaminants. their production and use have increased dramatically from the early 1980s. while many recent publications have reported concentrations of perfluorooctane sulfonate (pfos) and other perfluoroalkyl acids (pfas) in biotic and abiotic samples, only limited work has addressed temporal trends. in this study we analyzed archived polar bear(ursus maritimus) livertissue samples from two geographic locations in the north americ ...200616572767
effective interactions in colloid-semipermeable membrane systems.we investigate effective interactions between a colloidal particle, immersed in a binary mixture of smaller spheres, and a semipermeable membrane. the colloid is modeled as a big hard sphere, and the membrane is represented as an infinitely thin surface, which is fully permeable to one of the smaller spheres and impermeable to the other one. within the framework of the density functional theory, we evaluate depletion potentials and we consider two different approximate theories: the simple asaku ...200616548580
individual differences in self-reported thought control: the role of the repressive coping sytle.the purpose of the present research is to assess differences between repressors and non repressors in some aspects associated with conscious thought control. thus, sixty-three spanish university students with different combinations of trait anxiety and defensiveness completed the thought control ability questionnaire (tcaq) and the white bear suppression inventory (wbsi). data analysis showed that subjects with low anxiety (repressors and low anxious) reported higher perceived ability to control ...200617296036
working in canada's subarctic: circumpolar medicine.medical practice in churchill is a challenging and rewarding form of wilderness medicine. if any reader is interested in learning more about churchill or would like to consider visiting or even taking a health care position here, the following resources and contacts are available: the website for churchill independent travel (www.creighton.edu/hutchens/church_travel.html) gives a complete list of options for those wishing to plan their own trip. the arctic medicine conference is a medical confer ...200616538947
visual pigments of marine carnivores: pinnipeds, polar bear, and sea otter.rod and cone visual pigments of 11 marine carnivores were evaluated. rod, middle/long-wavelength sensitive (m/l) cone, and short-wavelength sensitive (s) cone opsin (if present) sequences were obtained from retinal mrna. spectral sensitivity was inferred through evaluation of known spectral tuning residues. the rod pigments of all but one of the pinnipeds were similar to those of the sea otter, polar bear, and most other terrestrial carnivores with spectral peak sensitivities (lambda(max)) of 49 ...200616572322
biomagnification of polybrominated diphenyl ether and hexabromocyclododecane flame retardants in the polar bear food chain in svalbard, norway.concentrations of brominated flame retardants (bfrs), including polybrominated diphenylethers (pbdes) and hexabromocyclododecane (hbcd), were investigated in an arctic marine food chain consisting of four invertebrate species: polar cod (boreogadus saida), ringed seals (pusa hispida), and polar bears (ursus maritimus). the most abundant bfr, brominated diphenyl ether (bde)-47, was found in detectable concentrations even in zooplankton, the lowest trophic level examined in this study. most of the ...200616986806
endocrine disrupters and female reproductive health.there is growing evidence of the impact of estrogenic contaminants in the environment. studies have shown that male fish in detergent-contaminated water express female characteristics, turtles are sex-reversed by polychlorinated biphenyls (pcbs), male frogs exposed to a common herbicide form multiple ovaries, pseudohermaphroditic offspring are produced by polar bears, and seals in contaminated water have an excess of uterine fibroids. endocrine-disrupting chemicals (those found in the external e ...200616522520
tracheitis associated with bordetella bronchiseptica in a polar bear (ursus maritimus).a male polar bear (ursus maritimus) was diagnosed with tracheitis associated with bordetella bronchiseptica that was cultured from an endotracheal sample of thick mucopurulent exudate. the condition responded to oral amoxicillin/clavulanic acid, and clinical signs of inappetence, depression, dysphagia, and tussis were resolved. one week after this presentation, a female conspecific presented with similar clinical signs, suggesting a transmissible nature of the disease or the same source of infec ...200617312800
trophic relationships in an arctic food web and implications for trace metal transfer.tissues of subsistence-harvested arctic mammals were analyzed for silver (ag), cadmium (cd), and total mercury (thg). muscle (or total body homogenates of potential fish and invertebrate prey) was analyzed for stable carbon (delta13c) and nitrogen (delta15n) isotopes to establish trophic interactions within the arctic food chain. food web magnification factors (fwmfs) and biomagnification factors for selected predator-prey scenarios (bmfs) were calculated to describe pathways of heavy metals in ...200616387350
radiocaesium (137cs) in marine mammals from svalbard, the barents sea and the north greenland sea.specific activities of the anthropogenic radionuclide, 137cs, were determined in marine mammals from svalbard and the barents and north greenland seas. muscle samples were collected from 12 polar bears, 15 ringed seals, 10 hooded seals, 7 bearded seals, 14 harp seals, one walrus, one white whale and one blue whale in the period 2000-2003. the mean concentrations (+/-sd) of 137cs were: 0.72+/-0.62 bq/kg wet weight (w.w.) for polar bears; 0.49+/-0.07 bq/kg w.w. for ringed seals; 0.25+/-0.10 bq/kg ...200616154620
levels and trends of brominated flame retardants in the arctic.polybrominated diphenyl ethers (pbdes) containing two to seven bromines are ubiquitous in arctic biotic and abiotic samples (from zooplankton to polar bears (ursus maritimus) and humans; air, soil, sediments). the fully brominated decabromodiphenyl ether (bde-209), hexabromocyclododecane (hbcd), tetrabromobisphenol a (tbbpa) and polybrominated biphenyls (pbbs) are also present in biotic and abiotic samples. spatial trends of pbdes and hbcd in top predators are similar to those seen for polychlor ...200616458344
xenoendocrine pollutants may reduce size of sexual organs in east greenland polar bears (ursus maritimus).reproductive organs from 55 male and 44 female east greenland polar bears were examined to investigate the potential negative impact from organohalogen pollutants (ohcs). multiple regressions normalizing for age showed a significant inverse relationship between ohcs and testis length and baculum length and weight, respectively, and was found in both subadults (dichlorodiphenyl trichloroethanes, dieldrin, chlordanes, hexacyclohexanes, polychlorinated biphenyls (pcbs), and polybrominated diphenyl ...200617007124
endocrine disruption induced by organochlorines (ocs): field studies and experimental models.long-range transport of persistent organic compounds by air and ocean currents from industrialized areas resulted in high levels of these pollutants in food webs in the svalbard area. with the aim to test if organochlorine (oc) exposure in free-living polar bears from svalbard affected their plasma steroid hormone concentrations, it was found that polychlorinated biphenyls (pcbs) were associated with increased progesterone levels in females. the sum of pesticides (sigma pesticides) and sigma pcb ...200616291562
levels of toxaphene congeners in white whales (delphinapterus leucas) from svalbard, norway.this study reports concentrations of three pesticide toxaphene congeners (chbs; chb-26, -50 and -62) from the blubber of ten adult, male white whales (delphinapterus leucas) from svalbard, norway. the chb congeners that occurred at the highest levels in the blubber of the white whales were, as expected, chb-26 (4636+/-1992 (sd) ng/g l.w.) and chb-50 (6579+/-2214 ng/g l.w.); chb-62 (232+/-231 ng/g l.w.) was also present, but at much lower concentrations. the mean level of the sum of the three chb ...200615975634
brominated flame retardants in polar bears (ursus maritimus) from alaska, the canadian arctic, east greenland, and svalbard.polybrominated diphenyl ethers (pbdes) were determined in adipose tissue of adult and subadult female polar bears sampled between 1999 and 2002 from sub-populations in arctic canada, eastern greenland, and svalbard, and in males and females collected from 1994 to 2002 in northwestern alaska. only 4 congeners (bde47, 99, 100, and 153) were consistently identified in all samples. bde47 was the major pbde congener representing from 65% to 82% of the sum (sigma) pbdes. age was not a significant cova ...200616468388
impairment of cellular immunity in west greenland sledge dogs (canis familiaris) dietary exposed to polluted minke whale (balaenoptera acutorostrata) blubber.minke whale (balaenoptera acutorostrata) blubber is rich in organohalogen contaminants, mercury, and n-3 fatty acids. in the present study we show that a daily intake of 50-200 g of minke whale blubber causes an impairment of the nonspecific and specific cellular immune system in the west greenland sledge dog (canis familiaris). immune reactions were measured by mitogen (pha, con a) and antigen (klh) intradermal testing, and as the study used exposure levels similar to those of inuits and polar ...200616570636
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