758 research outputs found

    Changes in the Numbers of Cetaceans near the Pribilof Islands, Bering Sea, between 1975-78 and 1987-89

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    We compared the number of cetaceans seen during surveys of seabird distribution in the vicinity of the Pribilof Islands, Bering Sea, during two periods, 1975-78 (3867 km surveyed) and 1987-89 (6101 km surveyed). During the 1980s, we saw increased numbers of fin whales (Balaenoptera physalus) (0 to 66 individuals), minke whales (B. acutorostrata) (3 to 38 individuals), humpback whales (Megaptera novaeangliae) (0 to 24 individuals), killer whales (Orcinus orca) (5 to 58 individuals), and Dall's porpoises (Phocoenoides dalli) (101 to 241 individuals). It could not be determined whether these changes reflected changes in the numbers of these species in the Bering Sea, or simply local changes in their foraging or distribution patterns. Fin, humpback and minke whales were seen foraging in the vicinity of large flocks of birds that were eating euphausiids (Thysanoessa raschii and T. inermis).Key words: Fin whale, minke whale, humpback whale, killer whale, Dall’s porpoise, Balaenoptera physalus, Balaenoptera acutorostrata, Megaptera novaeangliae, Orcinus orca, Phocoenoides dalli, Bering Sea, whale foragingOn a comparé le nombre de cétacés aperçus durant des relevés de la répartition d'oiseaux marins dans le voisinage des îles Pribilof, dans la mer de Béring, durant deux périodes de trois ans, de 1975 à 1978 (3867 km de distance de relevés) et de 1987 à 1989 (6101 km de distance de relevés). Au cours des années 1980, on a aperçu un plus grand nombre de rorquals communs (Balaenoptera physalus) [de 0 à 66 individus], de petits rorquals (B. acutorostrata) [de 3 à 38 individus], de rorquals à bosse (Megaptera novaeangliae) [de 0 à 24 individus], d'épaulards (Orcinus orca) [de 5 à 58 individus] et de marsouins de Dall (Phocoenoides dalli) [de 101 à 241 individus]. On n'a pu déterminer si ces changements reflétaient une évolution du nombre de ces espèces dans la mer de Béring, ou simplement des modifications locales dans les schémas d'alimentation ou de répartition. On a aperçu des rorquals communs, des rorquals à bosse et des petits rorquals en train de se nourrir à proximité de grandes volées d'oiseaux qui se nourrissaient d'euphausiacés (Thysanoessa raschii et T. inermis).Mots clés: rorqual commun, petit rorqual, rorqual à bosse, épaulard, marsouin de Dall, Balaenoptera physalus, Balaenoptera acutorostrata, Megaptera novoaeangliae, Orcinus orca, Phocoenoides dalli, mer de Béring, alimentation des baleine

    Modeling Underwater Visual and Filter Feeding by Planktivorous Shearwaters in Unusual Sea Conditions

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    Short-tailed Shearwaters (Puffinus tenuirostris) migrate between breeding areas in Australia and wintering areas in the Bering Sea. These extreme movements allow them to feed on swarms of euphausiids (krill) that occur seasonally in different regions, but they occasionally experience die-offs when availability of euphausiids or other prey is inadequate. During a coccolithophore bloom in the Bering Sea in 1997, hundreds of thousands of Short-tailed Shearwaters starved to death. One proposed explanation was that the calcareous shells of phytoplanktonic coccolithophores reduced light transmission, thus impairing visual foraging underwater. This hypothesis assumes that shearwaters feed entirely by vision (bite-feeding), but their unique bill and tongue morphology might allow nonvisual filter-feeding within euphausiid swarms. To investigate these issues, we developed simulation models of Short-tailed Shearwaters bite-feeding and filter-feeding underwater on the euphausiid Thysanoessa raschii. The visual (bite-feeding) model considered profiles of diffuse and beam attenuation of light in the Bering Sea among seasons, sites, and years with varying influence by diatom and coccolithophore blooms. The visual model indicated that over the huge range of densities in euphausiid swarms (tens to tens of thousands per cubic meter), neither light level nor prey density had appreciable effects on intake rate; instead, intake was severely limited by capture time and capture probability after prey were detected. Thus, for shearwaters there are strong advantages of feeding on dense swarms near the surface, where dive costs are low relative to fixed intake rate, and intake might be increased by filter-feeding. With minimal effects of light conditions, starvation of shearwaters during the coccolithophore bloom probably did not result from reduced visibility underwater after prey patches were found. Alternatively, turbidity from coccolithophores might have hindered detection of euphausiid swarms from the air

    Hydrographic Features, Cetaceans and the Foraging of Thick-billed Murres and Other Marine Birds in the Northwestern Barents Sea

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    The at-sea distribution of thick-billed murres (Uria lomvia) in southeastern Svalbard waters was studied during the summers of 1992, 1993, and 1996. The Storfjordrenna region south of Svalbard was confirmed as an important foraging area for thick-billed murres; murre aggregations were located at distances of 85 to 126 km from the closest breeding colonies. Fish, mainly polar cod (Boreogadus saida), but also capelin (Mallotus villosus), were the main prey found in 16 murres and 3 black-legged kittiwakes (Rissa tridactyla) collected from these aggregations. Murres were seen flying with fish in their beaks at four locations 78 to 102 km away from the colonies. Murre aggregations were associated with frontal zones between cold Arctic waters and warmer Atlantic water, and in areas with strong stratification in salinity at 15-30 m. A positive association was found between the abundance of murres and the occurrence of cetaceans. Murres and other marine birds were often seen near surfacing cetaceans. The most common cetaceans were minke whales (Balaenoptera acutorostrata) and white-beaked dolphins (Lagenorhynchus albirostris).Durant les étés de 1992, 1993 et 1996, on a étudié la distribution en mer de la marmette de Brünnich (Uria lomvia) dans les eaux du sud-est du Svalbard. La région Storfjordrenna au sud du Svalbard a été confirmée comme une zone importante de collecte pour la marmette de Brünnich; des concentrations de marmettes étaient situées à des distances allant de 85 à 126 km des colonies nicheuses les plus proches. Le poisson, en particulier la morue polaire (Boreogadus saida), mais aussi le capelan (Mallotus villosus), était la proie principale trouvée chez 16 marmettes et 3 mouettes tridactyles (Rissa tridactyla) prélevées dans ces concentrations. On a vu les marmettes voler avec du poisson dans leur bec à quatre endroits éloignés de 78 à 102 km des colonies. Les concentrations de marmettes étaient associées à des zones frontales entre les eaux froides de l'Arctique et l'eau plus chaude de l'Atlantique, et dans des régions ayant une forte stratification dans la salinité à une profondeur de 15 à 30 m. On a trouvé qu'il existait une association positive entre l'abondance des marmettes et la présence des cétacés. On voyait souvent les marmettes et d'autres oiseaux marins près des cétacés qui faisaient surface. Les cétacés les plus communs étaient les petits rorquals (Balaenoptera acutorostrata) et les dauphins à nez blanc (Lagenorhynchus albirostris)

    Distribution and Diet of Ivory Gulls (Pagophila eburnea) in the North Water

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    Ivory gulls (Pagophila eburnea, Phipps, 1774), one of the world’s least-known species, have declined throughout their range in recent years. This study describes the patterns of ivory gull use of the North Water polynya, a large polynya that occurs every year near ivory gull breeding sites on Ellesmere Island, Nunavut, Canada. We conducted at-sea surveys from Canadian icebreakers during the summers of 1997–99. In 1998, stomach contents of five ivory gulls were analyzed. We measured stable isotope ratios (d13C, d15N) of liver, muscle, feather and bone to determine how ivory gull diets vary during the year. We observed a total of 275 individuals, most of which were seen on the western side of the polynya. Flying was the predominant behavior (76% of individuals); other behaviors included sitting on ice, sitting on water, and feeding. Four juveniles were seen in August and September. Birds collected had arctic cod (Boreogadus saida) in their stomachs. Other food items included an otolith from an unidentified species of Liparid fish and two bones from a mole, presumed to be a star-nosed mole (Condylura cristata). Stable isotope results indicated that ivory gull trophic levels (TLs) were high (around TL 4 based on d15N) but varied over the season. From the three individuals whose feathers were analyzed, we conclude that differences among individuals in their winter diets or foraging locations are possible.Les mouettes blanches (Pagophila eburnea), soit l’une des espèces les moins connues dans le monde, ont enregistré un déclin à travers l’ensemble de leurs habitats ces dernières années. Cette étude décrit les habitudes des mouettes blanches dans la polynie des eaux du Nord, une grande polynie qui se développe chaque année près des sites de reproduction de mouettes blanches sur l’île Ellesmere, au Nunavut, Canada. Nous avons effectué des relevés depuis des brise-glace canadiens au cours des étés 1997 à 1999. En 1998, le contenu des estomacs de cinq mouettes blanches a été analysé. Nous avons également mesuré les ratios d’isotopes stables (d13C, d15N) dans les foies, les muscles, les plumages et les os afin de déterminer comment le régime alimentaire des mouettes blanches variait au cours de l’année. Nous avons observé 275 individus, provenant principalement du côté ouest de la Polynie. La majorité (76 %) étaient en vol. Parmi les autres comportements observés, notons la présence d’oiseaux sur la glace, d’oiseaux sur l’eau et d’oiseaux en train de se nourrir. Quatre oiseaux juvéniles ont été repérés en août et en septembre. Les oiseaux capturés avaient de la morue polaire (Boreogadus saida) dans l’estomac. Les autres aliments trouvés comprenaient un otolithe provenant d’une espèce non identifiée de poisson Liparidé, et deux os de taupe, probablement un condylure étoilé (Condylura cristata). L’analyse des isotopes stables indique que les niveaux trophiques (NT) des mouettes blanches étaient élevés (NT 4 environ en fonction de d15N), mais variaient au cours de la saison. À partir des trois individus dont les plumes ont été analysées, nous en avons conclu qu’il est possible qu’il existe des différences entre les régimes d’hiver ou les lieux de nourriture des individus

    The Suppressor of AAC2 Lethality SAL1 Modulates Sensitivity of Heterologously Expressed Artemia ADP/ATP Carrier to Bongkrekate in Yeast

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    The ADP/ATP carrier protein (AAC) expressed in Artemia franciscana is refractory to bongkrekate. We generated two strains of Saccharomyces cerevisiae where AAC1 and AAC3 were inactivated and the AAC2 isoform was replaced with Artemia AAC containing a hemagglutinin tag (ArAAC-HA). In one of the strains the suppressor of ΔAAC2 lethality, SAL1, was also inactivated but a plasmid coding for yeast AAC2 was included, because the ArAACΔsal1Δ strain was lethal. In both strains ArAAC-HA was expressed and correctly localized to the mitochondria. Peptide sequencing of ArAAC expressed in Artemia and that expressed in the modified yeasts revealed identical amino acid sequences. The isolated mitochondria from both modified strains developed 85% of the membrane potential attained by mitochondria of control strains, and addition of ADP yielded bongkrekate-sensitive depolarizations implying acquired sensitivity of ArAAC-mediated adenine nucleotide exchange to this poison, independent from SAL1. However, growth of ArAAC-expressing yeasts in glycerol-containing media was arrested by bongkrekate only in the presence of SAL1. We conclude that the mitochondrial environment of yeasts relying on respiratory growth conferred sensitivity of ArAAC to bongkrekate in a SAL1-dependent manner. © 2013 Wysocka-Kapcinska et al

    Stress-Induced Reinstatement of Drug Seeking: 20 Years of Progress

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    In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, first shown with an intermittent footshock stressor in rats trained to self-administer heroin, generalizes to other abused drugs, including cocaine, methamphetamine, nicotine, and alcohol, and is also observed in the conditioned place preference model in rats and mice. This phenomenon, however, is stressor specific and not all stressors induce reinstatement of drug seeking. (2) Neuropharmacological studies indicate the involvement of corticotropin-releasing factor (CRF), noradrenaline, dopamine, glutamate, kappa/dynorphin, and several other peptide and neurotransmitter systems in stress-induced reinstatement. Neuropharmacology and circuitry studies indicate the involvement of CRF and noradrenaline transmission in bed nucleus of stria terminalis and central amygdala, and dopamine, CRF, kappa/dynorphin, and glutamate transmission in other components of the mesocorticolimbic dopamine system (ventral tegmental area, medial prefrontal cortex, orbitofrontal cortex, and nucleus accumbens). (3) Translational human laboratory studies and a recent clinical trial study show the efficacy of alpha-2 adrenoceptor agonists in decreasing stress-induced drug craving and stress-induced initial heroin lapse

    A genome-wide association meta-analysis of self-reported allergy identifies shared and allergy-specific susceptibility loci

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    Allergic disease is very common and carries substantial public-health burdens. We conducted a meta-analysis of genome-wide associations with self-reported cat, dust-mite and pollen allergies in 53,862 individuals. We used generalized estimating equations to model shared and allergy-specific genetic effects. We identified 16 shared susceptibility loci with association P < 5 × 10-8, including 8 loci previously associated with asthma, as well as 4p14 near TLR1, TLR6 and TLR10 (rs2101521, P = 5.3 × 10 -21); 6p21.33 near HLA-C and MICA (rs9266772, P = 3.2 × 10 -12); 5p13.1 near PTGER4 (rs7720838, P = 8.2 × 10 -11); 2q33.1 in PLCL1 (rs10497813, P = 6.1 × 10-10), 3q28 in LPP (rs9860547, P = 1.2 × 10-9); 20q13.2 in NFATC2 (rs6021270, P = 6.9 × 10-9), 4q27 in ADAD1 (rs17388568, P = 3.9 × 10-8); and 14q21.1 near FOXA1 and TTC6 (rs1998359, P = 4.8 × 10-8). We identified one locus with substantial evidence of differences in effects across allergies at 6p21.32 in the class II human leukocyte antigen (HLA) region (rs17533090, P = 1.7 × 10-12), which was strongly associated with cat allergy. Our study sheds new light on the shared etiology of immune and autoimmune disease

    Compressed representation of a partially defined integer function over multiple arguments

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    In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one

    Torsional stability of interference screws derived from bovine bone - a biomechanical study

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    Introduction: It has been proposed that individual genetic variation contributes to the course of severe infections and sepsis. Recent studies of single nucleotide polymorphisms (SNPs) within the endotoxin receptor and its signaling system showed an association with the risk of disease development. This study aims to examine the response associated with genetic variations of TLR4, the receptor for bacterial LPS, and a central intracellular signal transducer (TIRAP/Mal) on cytokine release and for susceptibility and course of severe hospital acquired infections in distinct patient populations. Methods: Three intensive care units in tertiary care university hospitals in Greece and Germany participated. 375 and 415 postoperative patients and 159 patients with ventilator associated pneumonia (VAP) were included. TLR4 and TIRAP/Mal polymorphisms in 375 general surgical patients were associated with risk of infection, clinical course and outcome. In two prospective studies, 415 patients following cardiac surgery and 159 patients with newly diagnosed VAP predominantly caused by Gram-negative bacteria were studied for cytokine levels in-vivo and after ex-vivo monocyte stimulation and clinical course. Results: Patients simultaneously carrying polymorphisms in TIRAP/Mal and TLR4 and patients homozygous for the TIRAP/Mal SNP had a significantly higher risk of severe infections after surgery (odds ratio (OR) 5.5; confidence interval (CI): 1.34 - 22.64; P = 0.02 and OR: 7.3; CI: 1.89 - 28.50; P < 0.01 respectively). Additionally we found significantly lower circulating cytokine levels in double-mutant individuals with ventilator associated pneumonia and reduced cytokine production in an ex-vivo monocyte stimulation assay, but this difference was not apparent in TIRAP/Mal-homozygous patients. In cardiac surgery patients without infection, the cytokine release profiles were not changed when comparing different genotypes. Conclusions: Carriers of mutations in sequential components of the TLR signaling system may have an increased risk for severe infections. Patients with this genotype showed a decrease in cytokine release when infected which was not apparent in patients with sterile inflammation following cardiac surgery

    2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM Guidelines for the Diagnosis and Management of Patients With Thoracic Aortic Disease: A Report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine

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    The writing committee conducted a comprehensive search of the medical and scientific literature through the use of PubMed/MEDLINE. Searches were limited to publications written in the English language. Compiled reports were reviewed and additional articles were provided by committee members. Specifically targeted searches were conducted on the following subtopics: acute aortic dissection, ankylosing spondylitis, aortic dissection and litigation, aortic neoplasm, aortic tumors, Behçet disease, bicuspid aortic valve, calcified aorta, chronic dissection, coarctation of the aorta, D-dimer, dissecting aneurysm, Ehlers-Danlos syndrome, endovascular and aortic aneurysms, medial degeneration, porcelain aorta, giant cell arteritis, imaging and thoracic aortic disease, inflammatory disease, intramural hematoma, Loeys-Dietz syndrome, Marfan syndrome, Noonan syndrome, penetrating aortic ulcer, polycystic kidney disease, thoracic and aortic aneurysms, thoracic aortic disease and patient care, thoracic aortic disease and surgery, thoracic aorta and Kawasaki disease, Takayasu arteritis, thoracoabdominal and aorta or aortic disease, and Turner syndrome. More than 850 references were reviewed, with 830 used as the primary evidence base for the final guideline. The ACCF/AHA Task Force on Practice Guidelines methodology processes were followed to write the text and recommendations. In general, published manuscripts appearing in journals listed in Index Medicus were used as the evidence base. Published abstracts were used only for emerging information but were not used in the formulation of recommendations
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