| effects of polar bear and killer whale derived contaminant cocktails on marine mammal immunity. | most controlled toxicity studies use single chemical exposures that do not represent the real world situation of complex mixtures of known and unknown natural and anthropogenic substances. in the present study, complex contaminant cocktails derived from the blubber of polar bears (pb; ursus maritimus) and killer whales (kw; orcinus orca) were used for in vitro concentration-response experiments with pb, cetacean and seal spp. immune cells to evaluate the effect of realistic contaminant mixtures ... | 2017 | 28876915 |
| a rapid analytical method to quantify complex organohalogen contaminant mixtures in large samples of high lipid mammalian tissues. | in vitro investigations of the health impact of individual chemical compounds have traditionally been used in risk assessments. however, humans and wildlife are exposed to a plethora of potentially harmful chemicals, including organohalogen contaminants (ohcs). an alternative exposure approach to individual or simple mixtures of synthetic ohcs is to isolate the complex mixture present in free-ranging wildlife, often non-destructively sampled from lipid rich adipose. high concentration stock volu ... | 2017 | 28273531 |
| observation of emerging per- and polyfluoroalkyl substances (pfass) in greenland marine mammals. | the present pilot study examined emerging per- and polyfluoroalkyl substances (pfass), i.e., a suite of short chain perfluoroalkyl acids (pfaas), pfaa precursors and replacement chemicals, and legacy pfass (long chain length pfaas) in livers from ringed seals, polar bears and, for the first time, killer whales from east greenland collected in 2012-2013. among the emerging pfass, perfluorobutanesulfonic acid (pfbs) and f-53b (a chlorinated polyfluorinated ether sulfonic acid) were detected in arc ... | 2016 | 26610298 |
| analysis of zp1 gene reveals differences in zona pellucida composition in carnivores. | the zona pellucida (zp) is an extracellular envelope that surrounds mammalian oocytes. this coat participates in the interaction between gametes, induction of the acrosome reaction, block of polyspermy and protection of the oviductal embryo. previous studies suggested that carnivore zp was formed by three glycoproteins (zp2, zp3 and zp4), with zp1 being a pseudogene. however, a recent study in the cat found that all four proteins were expressed. in the present study, in silico and molecular anal ... | 2017 | 28679462 |
| genome-wide search identifies 1.9 mb from the polar bear y chromosome for evolutionary analyses. | the male-inherited y chromosome is the major haploid fraction of the mammalian genome, rendering y-linked sequences an indispensable resource for evolutionary research. however, despite recent large-scale genome sequencing approaches, only a handful of y chromosome sequences have been characterized to date, mainly in model organisms. using polar bear (ursus maritimus) genomes, we compare two different in silico approaches to identify y-linked sequences: 1) similarity to known y-linked genes and ... | 2015 | 26019166 |
| no need to replace an "anomalous" primate (primates) with an "anomalous" bear (carnivora, ursidae). | by means of mitochondrial 12s rrna sequencing of putative "yeti", "bigfoot", and other "anomalous primate" hair samples, a recent study concluded that two samples, presented as from the himalayas, do not belong to an "anomalous primate", but to an unknown, anomalous type of ursid. that is, that they match 12s rrna sequences of a fossil polar bear (ursusmaritimus), but neither of modern polar bears, nor of brown bears (ursusarctos), the closest relative of polar bears, and one that occurs today i ... | 2015 | 25829853 |
| 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 ... | 2008 | 18600311 |
| rapid radiation events in the family ursidae indicated by likelihood phylogenetic estimation from multiple fragments of mtdna. | the bear family (ursidae) presents a number of phylogenetic ambiguities as the evolutionary relationships of the six youngest members (ursine bears) are largely unresolved. recent mitochondrial dna analyses have produced conflicting results with respect to the phylogeny of ursine bears. in an attempt to resolve these issues, we obtained 1916 nucleotides of mitochondrial dna sequence data from six gene segments for all eight bear species and conducted maximum likelihood and maximum parsimony anal ... | 1999 | 10508542 |
| mitochondrial dna sequence evolution in the arctoidea. | some taxa in the superfamily arctoidea, such as the giant panda and the lesser panda, have presented puzzles to taxonomists. in the present study, approximately 397 bases of the cytochrome b gene, 364 bases of the 12s rrna gene, and 74 bases of the trna(thr) and trna(pro) genes from the giant panda, lesser panda, kinkajou, raccoon, coatimundi, and all species of the ursidae were sequenced. the high transition/transversion ratios in cytochrome b and rna genes prior to saturation suggest that the ... | 1993 | 8415740 |
| molecular genetic-distance estimates among the ursidae as indicated by one- and two-dimensional protein electrophoresis. | evolutionary relationships among eight species of ursidae (including the giant panda) relative to two procyonidae species (raccoon and red panda) were estimated based on the extent of electrophoretic variation of 289 radiolabelled fibroblast proteins resolved by two-dimensional gel electrophoresis and among 44 isozyme loci resolved by one-dimensional electrophoresis. allelic differences among these species were converted to genetic distances, and phenetic trees were constructed. in addition, the ... | 1989 | 28568545 |
| novel finding of widespread occurrence and accumulation of bisphenol a diglycidyl ethers (badges) and novolac glycidyl ethers (noges) in marine mammals from the united states coastal waters. | bisphenol a diglycidyl ether (badge)- and bisphenol f diglycidyl ether (bfdge)-based epoxy resins have a broad range of applications, including serving as inner coatings of food and beverage cans and as protective coatings in marine construction. prior to this study, no studies had examined the occurrence and bioaccumulation of badges or bfdges in aquatic organisms. in this study, badge, bfdge, and nine of their derivatives were determined in 121 tissue (liver, kidney, blubber, and brain) sample ... | 2016 | 26800265 |
| 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 ... | 2011 | 20869821 |
| 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 ... | 2006 | 16572322 |
| the future of dna-dna hybridization studies. | this article draws on many vertebrate examples to assess the future of dna-dna hybridization studies. i first discuss whether applications of the method have reached the point of diminishing returns, or rather the start of a great leap forward, in our evolutionary understanding. vertebrate groups whose relationships are especially likely to be illuminated include parrots, pigeons, bats, pinnipeds, mammalian carnivores, frogs, and rodents. there are at least two reasons why classifications based ... | 1990 | 2109084 |
| using simulation to evaluate wildlife survey designs: polar bears and seals in the chukchi sea. | logistically demanding and expensive wildlife surveys should ideally yield defensible estimates. here, we show how simulation can be used to evaluate alternative survey designs for estimating wildlife abundance. specifically, we evaluate the potential of instrument-based aerial surveys (combining infrared imagery with high-resolution digital photography to detect and identify species) for estimating abundance of polar bears and seals in the chukchi sea. we investigate the consequences of differe ... | 2016 | 26909183 |
| respiratory and olfactory turbinal size in canid and arctoid carnivorans. | within the nasal cavity of mammals is a complex scaffold of paper-thin bones that function in respiration and olfaction. known as turbinals, the bones greatly enlarge the surface area available for conditioning inspired air, reducing water loss, and improving olfaction. given their functional significance, the relative development of turbinal bones might be expected to differ among species with distinct olfactory, thermoregulatory and/or water conservation requirements. here we explore the surfa ... | 2012 | 23035637 |
| profile of persistent chlorinated contaminants, including selected chiral compounds, in wolverine (gulo gulo) livers from the canadian arctic. | wolverines (gulo gulo) are circumpolar omnivores that live throughout the alpine and arctic tundra ecosystem. wolverine livers were collected at kugluktuk (coppermine), nu (n=12) in the western canadian arctic to report, for the first time, the residue patterns of persistent organochlorine contaminants (ocs) in this species. the enantiomer fractions (efs) of several chiral ocs, including pcb atropisomers, in wolverines were also determined. results were compared to oc concentrations and efs of c ... | 2003 | 12948539 |
| distance measures and optimization spaces in quantitative fatty acid signature analysis. | quantitative fatty acid signature analysis has become an important method of diet estimation in ecology, especially marine ecology. controlled feeding trials to validate the method and estimate the calibration coefficients necessary to account for differential metabolism of individual fatty acids have been conducted with several species from diverse taxa. however, research into potential refinements of the estimation method has been limited. we compared the performance of the original method of ... | 2015 | 25859330 |
| phylogeny of the bears (ursidae) based on nuclear and mitochondrial genes. | the taxomic classification and phylogenetic relationships within the bear family remain argumentative subjects in recent years. prior investigation has been concentrated on the application of different mitochondrial (mt) sequence data, herein we employ two nuclear single-copy gene segments, the partial exon 1 from gene encoding interphotoreceptor retinoid binding protein (irbp) and the complete intron 1 from transthyretin (ttr) gene, in conjunction with previously published mt data, to clarify t ... | 2004 | 15223031 |
| musculoskeletal system of the neck of the polar bear (ursus maritimus) and the malayan bear (helarctos malayanus). | the gross anatomical study was undertaken in the musculoskeletal system of the neck of the polar bear, and the findings were compared with those of the malayan bear. the musculus splenius and the m. trapezius were well-developed in the polar bear. the long neck of the polar bear consisted mainly of the m. splenius with the m. biventer cervicis and the m. complexus lying tightly underneath. the cervical vertebrae possessed huge ventral tubercle in the ventral part of the transverse process in the ... | 2001 | 11206987 |
| [the occurrence of tumors in large bears (ursidae)--a literature review and six case descriptions]. | histological findings on two malayan sun bears and four sloth bears show that malignant neoplasms play an important role in tropic bears. further, most of the tumors originated from the hepatic and biliary tract. our results were compared with other investigations on zoo animals during the last 70 years revealing that malignant neoplasms are the most common ones in bears of the family ursidae. accordingly to our results, sloth and malayan sun bears seem to have a disposition to develop malignant ... | 1991 | 1930110 |
| the primary structure of the hemoglobin of malayan sun bear (helarctos malayanus, carnivora) and structural comparison to other hemoglobin sequences. | the complete primary structure of the alpha- and beta-chains of the hemoglobin of malayan sun bear (helarctos malayanus) is presented. after cleavage of the heme-protein link and chain separation by rp-hplc, amino-acid sequences were determined by edman degradation in liquid- and gas-phase sequenators. an interesting result of this work is the demonstration that the hemoglobin of malayan sun bear is identical to the hemoglobins of polar bear (ursus maritimus) and asiatic black bear (ursus tibeta ... | 1987 | 3620104 |
| effects of inedible, manipulable objects on captive bears. | bears in captivity often show abnormal behaviors such as stereotypies and periods of excessive inactivity. most of the research aimed at reducing abnormal behaviors in bears has focused on feeding enrichment. however, the effects of feeding enrichment only seem to last as long as it takes a bear to consume the food. this study investigated the effects of inedible, manipulable objects on bears. two polar bears (ursus maritimus) received plastic floats. a sloth bear (melursus ursinus) and a specta ... | 1999 | 16363951 |
| modeling population-level consequences of polychlorinated biphenyl exposure in east greenland polar bears. | polychlorinated biphenyls (pcbs) can cause endocrine disruption, cancer, immunosuppression, or reproductive failure in animals. we used an individual-based model to explore whether and how pcb-associated reproductive failure could affect the dynamics of a hypothetical polar bear (ursus maritimus) population exposed to pcbs to the same degree as the east greenland subpopulation. dose-response data from experimental studies on a surrogate species, the mink (mustela vision), were used in the absenc ... | 2016 | 26289812 |
| new support for polar bears and tigers. | | 2010 | 21210537 |
| biological transport and mammal to mammal transfer of organochlorines in arctic fauna. | ringed seal (phoca hispida) is assumed to be the most important and common prey of polar bears (ursus maritimus). however, during a scientific survey in the ice area of the northern barents sea east of svalbard in june 1995, an unexpectedly high number of polar bears were observed feeding on harp seal (phoca groenlandica) carcasses. samples of both harp and ringed seals were obtained and organochlorine (oc) occurrence and pattern in these two potential polar bear prey species were determined. si ... | 2000 | 11285735 |
| an arctic predator-prey system in flux: climate change impacts on coastal space use by polar bears and ringed seals. | climate change is impacting different species at different rates, leading to alterations in biological interactions with ramifications for wider ecosystem functioning. understanding these alterations can help improve predictive capacity and inform management efforts designed to mitigate against negative impacts. we investigated how the movement and space use patterns of polar bears (ursus maritimus) in coastal areas in svalbard, norway, have been altered by a sudden decline in sea ice that occur ... | 2017 | 28415134 |
| demographic, ecological, and physiological responses of ringed seals to an abrupt decline in sea ice availability. | to assess whether demographic declines of arctic species at the southern limit of their range will be gradual or punctuated, we compared large-scale environmental patterns including sea ice dynamics to ringed seal (pusa hispida) reproduction, body condition, recruitment, and stress in hudson bay from 2003 to 2013. aerial surveys suggested a gradual decline in seal density from 1995 to 2013, with the lowest density occurring in 2013. body condition decreased and stress (cortisol) increased over t ... | 2017 | 28168119 |
| risk of pop mixtures on the arctic food chain. | the exposure of the arctic ecosystem to persistent organic pollutants (pops) was assessed through a review of literature data. concentrations of 19 chemicals or congeneric groups were estimated for the highest levels of the arctic food chain (arctic cod, ringed seals, and polar bears). the ecotoxicological risk for seals, bears, and bear cubs was estimated by applying the concentration addition (ca) concept. the risk of pop mixtures was very low in seals. by contrast, the risk was 2 orders of ma ... | 2017 | 28054401 |
| current-use pesticides in seawater and their bioaccumulation in polar bear-ringed seal food chains of the canadian arctic. | the distribution of current-use pesticides (cups) in seawater and their trophodynamics were investigated in 3 canadian arctic marine food chains. the greatest ranges of dissolved-phase concentrations in seawater for each cup were endosulfan sulfate (less than method detection limit (mdl) to 19 pg l(-1) ) > dacthal (0.76-15 pg l(-1) ) > chlorpyrifos (less than mdl to 8.1 pg l(-1) ) > pentachloronitrobenzene (less than mdl to 2.6 pg l(-1) ) > α-endosulfan (0.20-2.3 pg l(-1) ). bioaccumulation fact ... | 2016 | 27027986 |
| enhanced biological processes associated with alopecia in polar bears (ursus maritimus). | populations of wildlife species worldwide experience incidents of mass morbidity and mortality. primary or secondary drivers of these events may escape classical detection methods for identifying microbial insults, toxin exposure, or additional stressors. in 2012, 28% of polar bears sampled in a study in the southern beaufort sea region of alaska had varying degrees of alopecia that was concomitant with reduced body condition. concurrently, elevated numbers of sick or dead ringed seals were dete ... | 2015 | 26005754 |
| mercury in the marine environment of the canadian arctic: review of recent findings. | this review summarizes data and information which have been generated on mercury (hg) in the marine environment of the canadian arctic since the previous canadian arctic contaminants assessment report (cacar) was released in 2003. much new information has been collected on hg concentrations in marine water, snow and ice in the canadian arctic. the first measurements of methylation rates in arctic seawater indicate that the water column is an important site for hg methylation. arctic marine water ... | 2015 | 24953756 |
| polar bears: the fate of an icon. | polar bears are one of the most iconic animals on our planet. worldwide, even people who would never see one are drawn to these charismatic arctic ice hunters. they are the world's largest terrestrial carnivore, and despite being born on land, they spend most of their lives out on the sea ice and are considered a marine mammal. current global studies estimate there are around 20,000 animals in some 19 discrete circumpolar populations. aside from pregnant females denning in the winter months to g ... | 2013 | 24331553 |
| trends of perfluorochemicals in greenland ringed seals and polar bears: indications of shifts to decreasing trends. | time-series of perfluorinated alkylated substances (pfass) in east greenland polar bears and east and west greenland ringed seals were updated in order to deduce whether a response to the major reduction in perfluoroalkyl production in the early 2000s had occurred. previous studies had documented an exponential increase of perfluorooctane sulphonate (pfos) in liver tissue from both species. in the present study, pfos was still the far most dominant compound constituting 92% (west greenland ringe ... | 2013 | 24025534 |
| effects of climate warming on polar bears: a review of the evidence. | climate warming is causing unidirectional changes to annual patterns of sea ice distribution, structure, and freeze-up. we summarize evidence that documents how loss of sea ice, the primary habitat of polar bears (ursus maritimus), negatively affects their long-term survival. to maintain viable subpopulations, polar bears depend on sea ice as a platform from which to hunt seals for long enough each year to accumulate sufficient energy (fat) to survive periods when seals are unavailable. less tim ... | 2012 | 24501049 |
| level and temporal trend of perfluoroalkyl acids in greenlandic inuit. | perfluoroalkyl acids (pfaas) have been detected in human blood, breast milk and umbilical cord blood across the globe. pfaas do accumulate in the marine food chain in arctic regions. in greenland, increasing pfaa concentrations were observed during 1982-2006 in ringed seals and polar bears. however, until now, no data have been reported for pfaas in greenlandic inuit. this study assesses the level and temporal trend of serum pfaas in greenlandic inuit. | 2012 | 22456049 |
| level and temporal trend of perfluoroalkyl acids in greenlandic inuit. | perfluoroalkyl acids (pfaas) have been detected in human blood, breast milk and umbilical cord blood across the globe. pfaas do accumulate in the marine food chain in arctic regions. in greenland, increasing pfaa concentrations were observed during 1982-2006 in ringed seals and polar bears. however, until now, no data have been reported for pfaas in greenlandic inuit. this study assesses the level and temporal trend of serum pfaas in greenlandic inuit. | 2012 | 28417759 |
| 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) ... | 2011 | 21166451 |
| 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 ... | 2010 | 20493516 |
| 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 ... | 2007 | 17702331 |
| persistent organic pollutants and mercury in marine biota of the canadian arctic: an overview of spatial and temporal trends. | this review summarizes and synthesizes the significant amount of data which was generated on mercury (hg) and persistent organic pollutants (pops) in canadian arctic marine biota since the first canadian arctic contaminants assessment report (cacar) was published in 1997. this recent body of work has led to a better understanding of the current levels and spatial and temporal trends of contaminants in biota, including the marine food species that northern peoples traditionally consume. compared ... | 2005 | 16109439 |
| preliminary screening of perfluorooctane sulfonate (pfos) and other fluorochemicals in fish, birds and marine mammals from greenland and the faroe islands. | extensive screening analyses of perfluorooctane sulfonate (pfos) and related perfluorinated compounds in biota samples from all over the world have identified pfos as a global pollutant and have shown its bioaccumulation into higher trophic levels in the food chain. perfluorinated compounds have been found in remote areas as the arctic. in this study a preliminary screening of pfos and related compounds has been performed in liver samples of fish, birds and marine mammals from greenland and the ... | 2005 | 15840540 |
| concentrations and interactions of selected essential and non-essential elements in ringed seals and polar bears of arctic alaska. | in this study, we evaluated concentrations of twelve essential and non-essential elements (as, cd, co, cu, pb, mg, mn, hg, mo, se, ag, and zn) in tissues of ringed seals (phoca hispida) and polar bears (ursus maritimus) of arctic alaska (usa). all samples were collected between 1995-97 in conjunction with subsistence harvests. the essential elements are reported to help develop reference ranges for health status determination and to help assess known or suspected interactions affecting toxicoses ... | 2001 | 11763734 |
| determination of toxaphenes in fish and marine mammals. | an analytical method for the determination of toxaphene in biological materials using gas chromatography with an electron capture detector (gc-ecd) has been established and validated for three single congeners (chlorinated bornanes (chb) 26, 50 and 62). the analytical method was based on a method for determination of pcb, ddt and other chlorinated pesticides. to include toxaphene congeners an extra step, adsorption chromatography on silica columns, was introduced to separate the pesticides from ... | 2000 | 10819223 |
| geographical differences and time trends of persistent organic pollutants in the arctic. | geographical and temporal trends of total pcbs (sigmapcbs) and hexachlorocyclohexanes (sigmahchs) have been examined in polar bear (ursus maritimus) adipose tissue and ringed seal (phoca hispida) blubber along a transect from alaska to svalbard and northern norway/western russia. pcb concentrations in polar bear show a strong west to east trend with higher levels in east greenland, svalbard. in ringed seal, highest pcb levels were found at two sites near the russian coast. sigmahchs levels in ri ... | 2000 | 10720717 |
| an assessment of selenium to mercury in greenland marine animals. | information on mercury and selenium molar relation in muscle, liver and kidney tissue of greenland marine animals is presented. in the majority of the samples selenium was present in a molar surplus to mercury. this was most clear in molluscs, crustaceans, fish and seabirds. a 1:1 molar ratio was found in tissues of marine mammals with high mercury concentrations (above approx. 10 nmol/g). this was most clearly demonstrated for liver and kidney tissue of polar bear and for ringed seal with high ... | 2000 | 10682353 |
| enantioselective gas chromatography/mass spectrometry of methylsulfonyl pcbs with application to arctic marine mammals. | four different commercially available cyclodextrin (cd) capillary gas chromatography (gc) columns were tested for the enantioselective separation of nine environmentally persistent atropisomeric 3- and 4-methylsulfonyl pcbs (meso2-cbs). the selected columns contained cyclodextrins with various cavity diameters (beta- or gamma-cd), which were methylated and/or tert-butyldimethylsilylated (tbdms) in the 2,3,6-o-positions. the beta-cd column with tbdms substituents in all of the 2,3,6-o-positions w ... | 1998 | 9751025 |
| polar bears make little use of terrestrial food webs: evidence from stable-carbon isotope analysis. | the mean stable-carbon isotope ratios (δ(13)c) for polar bear (ursus maritimus) tissues (bone collagen -15.7‰, muscle -17.7‰, fat -24.7‰) were close to those of the same tissues from ringed seals (phoca hispida) (-16.2‰, -18.1‰, and -26.1‰, respectively), which feed exclusively from the marine food chain. the δ(13)c values for 4 species of fruits to which polar bears have access when on land in summer ranged from -27.8 to -26.2‰, typical of terrestrial plants in the arctic. an animal's δ(13)c si ... | 1991 | 28313343 |
| geographical distribution of metals in livers of polar bears from the northwest territories, canada. | levels of ag, ca, cd, cu, fe, hg, k, mg, mn, na, p, se and zn were determined in livers of polar bears collected in 1984 in six zones in the lancaster sound. baffin bay and hudson bay areas of the northwest territories of canada and compared with data collected in 1982 for the western part of the canadian arctic. only levels of cu, k and zn were found to have no statistically significant differences among zones. the lowest levels of ca, fe, mg, mn, na and p were found in the western arctic, but ... | 1991 | 2063185 |
| the caloric value of whole ringed seals (phoca hispida) in relation to polar bear (ursus maritimus) ecology and hunting behavior. | | 1975 | 1167176 |
| isotopic incorporation and the effects of fasting and dietary lipid content on isotopic discrimination in large carnivorous mammals. | there has been considerable emphasis on understanding isotopic discrimination for diet estimation in omnivores. however, discrimination may differ for carnivores, particularly species that consume lipid-rich diets. here, we examined the potential implications of several factors when using stable isotopes to estimate the diets of bears, which can consume lipid-rich diets and, alternatively, fast for weeks to months. we conducted feeding trials with captive brown bears (ursus arctos) and polar bea ... | 2017 | 27153128 |
| an evolutionarily young polar bear (ursus maritimus) endogenous retrovirus identified from next generation sequence data. | transcriptome analysis of polar bear (ursus maritimus) tissues identified sequences with similarity to porcine endogenous retroviruses (perv). based on these sequences, four proviral copies and 15 solo long terminal repeats (ltrs) of a newly described endogenous retrovirus were characterized from the polar bear draft genome sequence. closely related sequences were identified by pcr analysis of brown bear (ursus arctos) and black bear (ursus americanus) but were absent in non-ursinae bear species ... | 2015 | 26610552 |
| growth trajectories in the cave bear and its extant relatives: an examination of ontogenetic patterns in phylogeny. | the study of postnatal ontogeny can provide insights into evolution by offering an understanding of how growth trajectories have evolved resulting in adult morphological disparity. the ursus lineage is a good subject for studying cranial and mandibular shape and size variation in relation to postnatal ontogeny and phylogeny because it is at the same time not diverse but the species exhibit different feeding ecologies. cranial and mandibular shapes of ursus arctos (brown bear), u. maritimus (pola ... | 2015 | 26525575 |
| introgressive hybridization: brown bears as vectors for polar bear alleles. | the dynamics and consequences of introgression can inform about numerous evolutionary processes. biologists have therefore long been interested in hybridization. one challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. in this issue of molecular ecology, cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one american black bear. polar bear alleles are found to be introgr ... | 2015 | 25775930 |
| polar and brown bear genomes reveal ancient admixture and demographic footprints of past climate change. | polar bears (pbs) are superbly adapted to the extreme arctic environment and have become emblematic of the threat to biodiversity from global climate change. their divergence from the lower-latitude brown bear provides a textbook example of rapid evolution of distinct phenotypes. however, limited mitochondrial and nuclear dna evidence conflicts in the timing of pb origin as well as placement of the species within versus sister to the brown bear lineage. we gathered extensive genomic sequence dat ... | 2012 | 22826254 |
| 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 ... | 2008 | 18249018 |
| genetic diversity and differentiation of kermode bear populations. | the kermode bear is a white phase of the north american black bear that occurs in low to moderate frequency on british columbia's mid-coast. to investigate the genetic uniqueness of populations containing the white phase, and to ascertain levels of gene flow among populations, we surveyed 10 highly polymorphic microsatellite loci, assayed from trapped bear hairs. a total of 216 unique bear genotypes, 18 of which were white, was sampled among 12 localities. island populations, where kermodes are ... | 2002 | 11972757 |
| annual changes in serum sex steroids in male and female black (ursus americanus) and polar (ursus maritimus) bears. | the adaptation of black and polar bears to their environments is proportional to the severity of climate and food restriction. both black and polar bears mate during the spring, despite differences in their recent metabolic state. reproductive activity in black bears follows 4 mo of torpor, whereas reproduction in polar bears occurs prior to torpor. the goals of this study were to measure the annual changes in serum sex steroids in male and female black and polar bears, and to determine if chang ... | 1988 | 3408772 |
| trichinella and polar bears: a limited risk for humans. | in this review, we identified 63 cases reported since world war ii of human trichinellosis linked to the consumption of parasitized polar bear (ursus maritimus) meat. this low number contrasts to the numerous cases of human trichinellosis related to consumption of the meat of black (u. americanus) or brown bears (u. arctos). the prevalence of trichinella infection is high in bears, but larval muscular burden is usually lower in polar bears compared to other bear species. polar bears, therefore, ... | 2017 | 28372597 |
| comparison of methanol and isopropanol as wash solvents for determination of hair cortisol concentration in grizzly bears and polar bears. | methodological differences among laboratories are recognized as significant sources of variation in quantification of hair cortisol concentration (hcc). an important step in processing hair, particularly when collected from wildlife, is the choice of solvent used to remove or "wash" external hair shaft cortisol prior to quantification of hcc. the present study systematically compared methanol and isopropanol as wash solvents for their efficiency at removing external cortisol without extracting i ... | 2017 | 28203534 |
| evaluating random search strategies in three mammals from distinct feeding guilds. | searching allows animals to find food, mates, shelter and other resources essential for survival and reproduction and is thus among the most important activities performed by animals. theory predicts that animals will use random search strategies in highly variable and unpredictable environments. two prominent models have been suggested for animals searching in sparse and heterogeneous environments: (i) the lévy walk and (ii) the composite correlated random walk (ccrw) and its associated area-re ... | 2016 | 27354185 |
| y-chromosomal testing of brown bears (ursus arctos): validation of a multiplex pcr-approach for nine strs suitable for fecal and hair samples. | high-resolution y-chromosomal markers have been applied to humans and other primates to study population genetics, migration, social structures and reproduction. y-linked markers allow the direct assessment of the genetic structure and gene flow of uniquely male inherited lineages and may also be useful for wildlife conservation and forensics, but have so far been available only for few wild species. thus, we have developed two multiplex pcr reactions encompassing nine y-str markers identified f ... | 2015 | 26264959 |
| the role of pleistocene glaciations in shaping the evolution of polar and brown bears. evidence from a critical review of mitochondrial and nuclear genome analyses. | in this report, i review recent molecular studies dealing with the origin and evolution of polar bears (ursus maritimus), with special emphasis on their relationships with brown bears (u. arctos). on the basis of mitochondrial and nuclear data, different hypotheses have been proposed, including rapid morphological differentiation of u. maritimus, genetic introgression from u. arctos into u. maritimus, or inversely from u. maritimus into u. arctos, involving either male- or female-mediated gene f ... | 2015 | 26026577 |
| implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming arctic. | we provide an expansive analysis of polar bear (ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. we sought to evaluate whether their genetic diversity and structure have changed over this period of habitat decline, how their current genetic patterns compare with past patterns, and how genetic demography changed with ancient fluctuations in climate. characterizing their circumpolar genetic structure using microsatellite data, we defin ... | 2015 | 25562525 |
| genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears. | polar bears are an arctic, marine adapted species that is closely related to brown bears. genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. however, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the admiralty, baranof and chichagof islands (abc islands) of alaska. here, we present an analysis of data from a large panel of polar bear and brown bear ge ... | 2015 | 25490862 |
| grizzly bear hair reveals toxic exposure to mercury through salmon consumption. | mercury obtained from the diet accumulates in mammalian hair as it grows thus preserving a record of mercury intake over the growth period of a given hair segment. we adapted a microanalysis approach, using laser ablation inductively coupled plasma mass spectrometry, to characterize temporal changes in mercury exposure and uptake in wild and captive grizzly bears. captive grizzlies fed diets containing known and varied amounts of mercury provided data to allow prediction of hg ingestion rates in ... | 2014 | 24904971 |
| study yields “genghis khan” of brown bears, new understanding of brown and polar bear evolution. | | 2014 | 24860012 |
| population genomics reveal recent speciation and rapid evolutionary adaptation in polar bears. | polar bears are uniquely adapted to life in the high arctic and have undergone drastic physiological changes in response to arctic climates and a hyper-lipid diet of primarily marine mammal prey. we analyzed 89 complete genomes of polar bear and brown bear using population genomic modeling and show that the species diverged only 479-343 thousand years bp. we find that genes on the polar bear lineage have been under stronger positive selection than in brown bears; nine of the top 16 genes under s ... | 2014 | 24813606 |
| brown and polar bear y chromosomes reveal extensive male-biased gene flow within brother lineages. | brown and polar bears have become prominent examples in phylogeography, but previous phylogeographic studies relied largely on maternally inherited mitochondrial dna (mtdna) or were geographically restricted. the male-specific y chromosome, a natural counterpart to mtdna, has remained underexplored. although this paternally inherited chromosome is indispensable for comprehensive analyses of phylogeographic patterns, technical difficulties and low variability have hampered its application in most ... | 2014 | 24667925 |
| polar bears exhibit genome-wide signatures of bioenergetic adaptation to life in the arctic environment. | polar bears (ursus maritimus) face extremely cold temperatures and periods of fasting, which might result in more severe energetic challenges than those experienced by their sister species, the brown bear (u. arctos). we have examined the mitochondrial and nuclear genomes of polar and brown bears to investigate whether polar bears demonstrate lineage-specific signals of molecular adaptation in genes associated with cellular respiration/energy production. we observed increased evolutionary rates ... | 2014 | 24504087 |
| ancestral polymorphisms and sex-biased migration shaped the demographic history of brown bears and polar bears. | recent studies have reported discordant gene trees in the evolution of brown bears and polar bears. genealogical histories are different among independent nuclear loci and between biparentally inherited autosomal dna (adna) and matrilineal mitochondrial dna (mtdna). based on multi-locus genomic sequences from adna and mtdna, we inferred the population demography of brown and polar bears and found that brown bears have 6 times (adna) or more than 14 times (mtdna) larger population sizes than pola ... | 2013 | 24236053 |
| a simple and novel method for retrieval of pasteurellaceae from swab samples collected in the field. | traditionally it has been difficult or impossible to collect and preserve bacterial samples of especially fastidious bacteria in mixed primary cultures, unless the samples could be transported to a laboratory within approximately 24 h. therefore, a simple novel method for preserving swab samples until bacterial isolation can be completed in the laboratory was developed and evaluated. pasteurellaceae bacteria were used as a representative for fastidious bacteria. a 7.5% glucose serum medium was u ... | 2013 | 23897719 |
| could brown bears (ursus arctos) have survived in ireland during the last glacial maximum? | brown bears are recorded from ireland during both the late pleistocene and early-mid holocene. although most of the irish landmass was covered by an ice sheet during the last glacial maximum (lgm), irish brown bears are known to have hybridized with polar bears during the late pleistocene, and it is suggested that the irish brown bear population did not become extinct but instead persisted in situ through the lgm in a southwestern ice-free refugium. we use historical population modelling to demo ... | 2013 | 23676655 |
| molecular phylogeography of the brown bear (ursus arctos) in northeastern asia based on analyses of complete mitochondrial dna sequences. | to further elucidate the migration history of the brown bears (ursus arctos) on hokkaido island, japan, we analyzed the complete mitochondrial dna (mtdna) sequences of 35 brown bears from hokkaido, the southern kuril islands (etorofu and kunashiri), sakhalin island, and the eurasian continent (continental russia, bulgaria, and tibet), and those of four polar bears. based on these sequences, we reconstructed the maternal phylogeny of the brown bear and estimated divergence times to investigate th ... | 2013 | 23619144 |
| comment on "nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage". | based on nuclear and mitochondrial dna, hailer et al. (reports, 20 april 2012, p. 344) suggested early divergence of polar bears from a common ancestor with brown bears and subsequent introgression. our population genetic analysis that traces each of the genealogies in the independent nuclear loci does not support the evolutionary model proposed by the authors. | 2013 | 23539580 |
| genomic evidence for island population conversion resolves conflicting theories of polar bear evolution. | despite extensive genetic analysis, the evolutionary relationship between polar bears (ursus maritimus) and brown bears (u. arctos) remains unclear. the two most recent comprehensive reports indicate a recent divergence with little subsequent admixture or a much more ancient divergence followed by extensive admixture. at the center of this controversy are the alaskan abc islands brown bears that show evidence of shared ancestry with polar bears. we present an analysis of genome-wide sequence dat ... | 2013 | 23516372 |
| genetic relationships of extant brown bears (ursus arctos) and polar bears (ursus maritimus). | polar bears (ursus maritimus) and brown bears (ursus arctos) are closely related species for which extensive mitochondrial and nuclear phylogenetic comparisons have been made. we used previously published genotype data for 8 microsatellite dna loci from 930 brown bears in 19 populations and 473 polar bears in 16 populations to compare the population genetic relationships of extant populations of the species. genetic distances (nei standard distance = 1.157), the proportion of private alleles (52 ... | 2012 | 23125409 |
| nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage. | recent studies have shown that the polar bear matriline (mitochondrial dna) evolved from a brown bear lineage since the late pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle pleis ... | 2012 | 22517859 |
| 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 ... | 2010 | 20194737 |
| an empirical evaluation of genetic distance statistics using microsatellite data from bear (ursidae) populations. | a large microsatellite data set from three species of bear (ursidae) was used to empirically test the performance of six genetic distance measures in resolving relationships at a variety of scales ranging from adjacent areas in a continuous distribution to species that diverged several million years ago. at the finest scale, while some distance measures performed extremely well, statistics developed specifically to accommodate the mutational processes of microsatellites performed relatively poor ... | 1997 | 9409849 |
| variables affecting the manifestation of and intensity of pacing behavior: a preliminary case study in zoo-housed polar bears. | high-speed video analysis was used to quantify two aspects of gait in 10 zoo-housed polar bears. these two variables were then examined as to how they differed in the conditions of pacing versus locomoting for each bear. percent difference calculations measured the difference between pacing and locomoting data for each bear. we inferred that the higher the percent difference between pacing and locomoting in a given subject, the more intense the pacing may be. the percent difference values were a ... | 2017 | 28901667 |
| simultaneous estimation of diet composition and calibration coefficients with fatty acid signature data. | knowledge of animal diets provides essential insights into their life history and ecology, although diet estimation is challenging and remains an active area of research. quantitative fatty acid signature analysis (qfasa) has become a popular method of estimating diet composition, especially for marine species. a primary assumption of qfasa is that constants called calibration coefficients, which account for the differential metabolism of individual fatty acids, are known. in practice, however, ... | 2017 | 28861216 |
| polar bears experience skeletal muscle atrophy in response to food deprivation and reduced activity in winter and summer. | when reducing activity and using stored energy during seasonal food shortages, animals risk degradation of skeletal muscles, although some species avoid or minimize the resulting atrophy while experiencing these conditions during hibernation. polar bears may be food deprived and relatively inactive during winter (when pregnant females hibernate and hunting success declines for other demographic groups) as well as summer (when sea ice retreats from key foraging habitats). we investigated muscle a ... | 2017 | 28835844 |
| legacy and new halogenated persistent organic pollutants in polar bears from a contamination hotspot in the arctic, hudson bay canada. | a large and complex suite of 295 legacy and new halogenated persistent organic pollutants (pops) were investigated in fat or liver tissue samples of polar bears collected in 2013-2014 from southern (shb) and western (whb) subpopulations of the canadian arctic contaminants hotspot of hudson bay. a total of 210 pops were detected and/or quantifiable with some frequency in all fat or liver samples. pop profile and concentration differences were investigated both within (e.g. age and sex) and betwee ... | 2017 | 28803190 |
| comparative genomics analyses of alpha-keratins reveal insights into evolutionary adaptation of marine mammals. | diversity of hair in marine mammals was suggested as an evolutionary innovation to adapt aquatic environment, yet its genetic basis remained poorly explored. we scanned α-keratin genes, one major structural components of hair, in 16 genomes of mammalian species, including seven cetaceans, two pinnipeds, polar bear, manatee and five terrestrial species. | 2017 | 28785294 |
| relationships between pops, biometrics and circulating steroids in male polar bears (ursus maritimus) from svalbard. | the aim of this study was to determine the effects of persistent organic pollutants (pops) and biometric variables on circulating levels of steroid hormones (androgens, estrogens and progestagens) in male polar bears (ursus maritimus) from svalbard, norway (n = 23). levels of pregnenolone (pre), progesterone (pro), androstenedione (an), dehydroepiandrosterone (dhea), testosterone (ts), dihydrotestosterone (dht), estrone (e1), 17α-estradiol (αe2) and 17β-estradiol (βe2) were quantified in polar b ... | 2017 | 28710978 |
| analysis and characterization of polychlorinated hydroxybornanes as metabolites of toxaphene using a polar bear model. | abiotic and biotic transformation of toxaphene (camphechlor) results in the selective enrichment of recalcitrant congeners while other, less persistent compounds of technical toxaphene (ctts) are degraded. until now, there has been little knowledge on oxidation transformation of toxaphene. for instance, the existence of hydroxylated ctts (oh-ctts) in authentic environmental and food samples has not been proven. for this reason, we synthesized a mixture consisting of tetra- to heptachlorinated oh ... | 2017 | 28686017 |
| lumbar laminectomy in a captive, adult polar bear (ursus maritimus). | animals held in captivity tend to live longer than do their wild counterparts, and as such, are prone to developing age-related degenerative injuries. here, we present a case of an adult female polar bear with symptomatic lumbar stenosis. there is a paucity of literature on large mammalian spine surgery, and anatomical differences between humans and other vertebrates must be taken into consideration. | 2017 | 28680731 |
| potentiation of ecological factors on the disruption of thyroid hormones by organo-halogenated contaminants in female polar bears (ursus maritimus) from the barents sea. | as apex predators, polar bears (ursus maritimus) are among the most heavily polluted organisms in the arctic. in addition to this anthropogenic stressor, climate warming has been shown to negatively affect their body condition, reproductive output and survival. among potential underlying physiological mechanisms, thyroid hormones (ths), which control thermoregulation, metabolism and reproduction, can be affected by a variety of both natural and anthropogenic factors. while ths have been extensiv ... | 2017 | 28614731 |
| ecological change drives a decline in mercury concentrations in southern beaufort sea polar bears. | we evaluated total mercury (thg) concentrations and trends in polar bears from the southern beaufort sea subpopulation from 2004 to 2011. hair thg concentrations ranged widely among individuals from 0.6 to 13.3 μg g(-1) dry weight (mean: 3.5 ± 0.2 μg g(-1)). concentrations differed among sex and age classes: solitary adult females ≈ adult females with cubs ≈ subadults > adult males ≈ yearlings > cubs-of-the-year ≈ 2 year old dependent cubs. no variation was observed between spring and fall sampl ... | 2017 | 28612610 |
| postlaparoscopic reduction of pain by combining intraperitoneal normal saline and the pulmonary recruitment maneuver (polar bear trial). rct to estimate reduction in pain after laparoscopic surgery when using a combination therapy of intraperitoneal normal saline and the pulmonary recruitment maneuver. | shoulder pain and pain in the upper abdomen are common complaints after laparoscopy, sometimes surpassing the pain at incision sites. the incidence of shoulder pain ranges from 35 to 80%. post-laparoscopic pain is caused by retention of carbon dioxide in the abdomen, which irritates the phrenic nerve and diaphragm, causing referred pain in the shoulder and in the upper abdomen. a promising strategy to reduce this post-laparoscopic pain is the pulmonary recruitment maneuver, which indirectly incr ... | 2017 | 28610572 |
| diet and metabolic state are the main factors determining concentrations of perfluoroalkyl substances in female polar bears from svalbard. | perfluoroalkyl substances (pfass) have been detected in organisms worldwide, including polar regions. the polar bear (ursus maritimus), the top predator of arctic marine ecosystems, accumulates high concentrations of pfass, which may be harmful to their health. the aim of this study was to investigate which factors (habitat quality, season, year, diet, metabolic state [i.e. feeding/fasting], breeding status and age) predict pfas concentrations in female polar bears captured on svalbard (norway). ... | 2017 | 28587979 |
| increased arctic sea ice drift alters adult female polar bear movements and energetics. | recent reductions in thickness and extent have increased drift rates of arctic sea ice. increased ice drift could significantly affect the movements and the energy balance of polar bears (ursus maritimus) which forage, nearly exclusively, on this substrate. we used radio-tracking and ice drift data to quantify the influence of increased drift on bear movements, and we modeled the consequences for energy demands of adult females in the beaufort and chukchi seas during two periods with different s ... | 2017 | 28586523 |
| urinary profiles of progestin and androgen metabolites in female polar bears during parturient and non-parturient cycles. | due to the environmental and anthropogenic impacts that continue to threaten the reproductive success of polar bears, a more detailed understanding of their reproductive cycle is needed. captive populations of polar bears provide an excellent opportunity to learn more about the reproductive physiology of the species. progestin (p4) and androgen (t) metabolites in urine, and their ratio (p4:t), were examined during 11 reproductive cycles of captive female polar bears (n = 4) to characterize the s ... | 2017 | 28458884 |
| movement of a female polar bear (ursus maritimus) in the kara sea during the summer sea-ice break-up. | the polar bear movement trajectory in relation to onset date of the sea-ice break-up was studied in the coastal zone of the taimyr peninsula, eastern part of the kara sea, using as an example a female polar bear tagged by a radio collar with an argos satellite transmitter. analysis of the long-term pattern of ice melting and tracking, by means of satellite telemetry, of the female polar bear who followed the ice-edge outgoing in the north-eastern direction (in summer 2012) suggests that directio ... | 2017 | 28429262 |
| corrigendum to "sea ice-associated decline in body condition leads to increased concentrations of lipophilic pollutants in polar bears (ursus maritimus) from svalbard, norway" [sci. total environ. 576 (2017) 409-419]. | | 2017 | 28411564 |
| windscapes and olfactory foraging in a large carnivore. | the theoretical optimal olfactory search strategy is to move cross-wind. empirical evidence supporting wind-associated directionality among carnivores, however, is sparse. we examined satellite-linked telemetry movement data of adult female polar bears (ursus maritimus) from hudson bay, canada, in relation to modelled winds, in an effort to understand olfactory search for prey. in our results, the predicted cross-wind movement occurred most frequently at night during winter, the time when most h ... | 2017 | 28402340 |
| predator-prey-subsidy population dynamics on stepping-stone domains. | predator-prey-subsidy dynamics on stepping-stone domains are examined using a variety of network configurations. our problem is motivated by the interactions between arctic foxes (predator) and lemmings (prey) in the presence of seal carrion (subsidy) provided by polar bears. we use the n-patch model, which considers space explicitly as a "stepping stone" system. we consider the role that the carrying capacity, predator migration rate, input subsidy rate, predator mortality rate, and proportion ... | 2017 | 28322876 |
| combined thin layer chromatography and gas chromatography with mass spectrometric analysis of lipid classes and fatty acids in malnourished polar bears (ursus maritimus) which swam to iceland. | between 2008 and 2011, four polar bears (ursus maritimus) from the greenland population swam and/or drifted on ice to iceland where they arrived in very poor body condition. body fat resources in these animals were only between 0% and 10% of the body weight (usually 25%). here we studied the lipid composition in different tissues (adipose tissue if available, liver, kidney and muscle). lipid classes were determined by thin layer chromatography (tlc) and on-column gas chromatography with mass spe ... | 2017 | 28183043 |
| depressive symptomatology and priming effects among younger and older adults. | background/study context: this study examined the potential impact of self-reported depressive symptoms on the age-related capacity for inhibition and suppression, utilizing a negative priming paradigm. | 2017 | 28067611 |