259 research outputs found

    Inheritance

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    Prolonged chemical restraint of walrus (Odobenus rosmarus) with etorphine supplemented with medetomidine

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    Physiological studies involving the use of isotopic water required chemical restraint of free- ranging walruses (Odobenus rosmarus) for several hours. In August 2000, six male walrus (total body mass: 1050–1550 kg) were immobilized in East Greenland by remote delivery of 8.0–9.8 mg of etorphine and subsequently restrained for up to 6.75 h by administration of medetomidine. The effects of etorphine were reversed with 10–24 mg diprenorphine. After termination of the etorphine-induced apnoea, lasting an average of 15.8 min (SD = 9.7, range = 9.5–35.2 min, n = 6), the animals were initially given 10–20 mg medetomidine intramuscularly. The initial dose was further augmented by 5 mg at intervals of 5 min. In two cases, when medetomidine was administered through a catheter inserted in the extradural vein, the animal became instantly apnoeic and regained respiratory function only after intravenous injection of the prescribed dose of the antagonist atipamezole and of the respiratory stimulant doxapram. After an average of 3.5 hours of immobilisation, rectal temperature began to increase and it is conceivable that this is the factor that will ultimately limit the duration of immobilisation. The animals became conscious and fully mobile shortly after an intravenous injection of a dose of atipamezole approximately twice the mass of the total dose of medetomidine given during the procedure followed by 400 mg of doxapram. It is concluded that medetomidine appears to be a suitable drug for chemical restraint of walruses for time-consuming procedures following initial immobilisation by etorphine. With animals of total body mass around 1,000–1,500 kg, the drug should be given intramuscularly in 10–20 mg increments (total mass 10–60 mg) until the breathing rate falls to approximately 1 min-1. At this level, breathing is maintained and animals do not respond to touch or injection

    Total mercury in hair of polar bears (Ursus maritimus) from Greenland and Svalbard

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    Concentrations (ppm = ug/g dry weight) of total mercury (Hg) were determined in hair of polar bears (Ursus maritimus) from northwestern Greenland (N = 22; period of sampling: 1978-1989), eastern Greenland (N = 44: 1984-1989) and Svalbard (N = 31; 1980). For subadults (2-6 years of life), adults (7-10 years). and old bears (>10 years), concentrations of total Hg in hair were not found to be dependent on age or sex. A decreasing trend in Hg concentrations was found from west to east. The mean concentrations of total Hg in hair (cubs of the year and yearlings excluded) were: northwestern Greenland, x = 8.38 ppm (min.-max.: 4.71-14.19 ppm. N = 21); eastern Greenland: x = 4.58 ppm (min.-max.: 2.50-8.83 ppm. N = 41); and Svalbard, x = 1.98 ppm (min.-max.: 1.02-4.55 ppm, N = 29). Concentrations found in northwestern Greenland were similar to those reported by others from the hair of polar bears sampled within management zone F of the eastern Canadian High Arctic. Concentrations of total Hg in polar bear hair from eastern Greenland were similar to concentrations found by others in contemporary (1988) material collected during spring in western Svalbard. However, the mean concentration of total Hg in the 1980 Svalbard material, which was collected during July-September, was significantly lower than concentrations found in samples taken during late winter and spring in eastern Greenland and at Svalbard, respectively. Presumably the relatively low concentrations found in the 1980 Svalbard sample arc attributable to the period of moult and hence a larger proportion of newly grown hair in the individual samples. In a subsample consisting of internal tissues from 19 polar bears from eastern Greenland (1984-1987), concentrations of total Hg in hair correlated positively with concentrations of total Hg (wet weight) in muscle (N = 6), liver (N = 19) and kidney (N = 19) tissue. For liver and kidney tissue these relationships were statistically significant

    Do Wild Polar Bears (Ursus maritimus) Use Tools When Hunting Walruses (Odobenus rosmarus)?

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    Since the late 1700s, reports of polar bears (Ursus maritimus) using tools (i.e., pieces of ice or stones) to kill walruses (Odobenus rosmarus) have been passed on verbally to explorers and naturalists by their Inuit guides, based on local traditional ecological knowledge (TEK) as well as accounts of direct observations or interpretations of tracks in the snow made by the Inuit hunters who reported them. To assess the possibility that polar bears may occasionally use tools to hunt walruses in the wild, we summarize 1) observations described to early explorers and naturalists by Inuit hunters about polar bears using tools, 2) more recent documentation in the literature from Inuit hunters and scientists, and 3) recent observations of a polar bear in a zoo spontaneously using tools to access a novel food source. These observations and previously published experiments on brown bears (Ursus arctos) confirm that, in captivity, polar and brown bears are both capable of conceptualizing the use of a tool to obtain a food source that would otherwise not be accessible. Based on the information from all our sources, this may occasionally also have been the case in the wild. We suggest that possible tool use by polar bears in the wild is infrequent and mainly limited to hunting walruses because of their large size, difficulty to kill, and their possession of potentially lethal weapons for both their own defense and the direct attack of a predator. Depuis la fin des annĂ©es 1700, des signalements d’ours polaires (Ursus maritimus) se servant d’outils (comme des morceaux de glace ou des pierres) pour tuer des morses (Odobenus rosmarus) ont Ă©tĂ© communiquĂ©s verbalement par des guides inuits Ă  divers explorateurs et naturalistes. Les guides en question se fondaient sur les connaissances Ă©cologiques traditionnelles (CET) locales de mĂŞme que sur les interprĂ©tations de traces dans la neige ou les rĂ©cits d’observations directes des chasseurs inuits ayant fait les signalements. Pour Ă©valuer la possibilitĂ© que les ours polaires puissent parfois se servir d’outils pour chasser les morses en milieu sauvage, nous rĂ©sumons : 1) les observations dĂ©crites aux premiers explorateurs et naturalistes par les chasseurs inuits au sujet de l’utilisation d’outils par les ours polaires; 2) la documentation rĂ©cente attribuable aux chasseurs inuits et aux scientifiques; et 3) les rĂ©centes observations de l’ours polaire d’un zoo se servant d’outils spontanĂ©ment pour avoir accès Ă  une nouvelle source de nourriture. Ces observations, alliĂ©es Ă  des expĂ©riences publiĂ©es au sujet d’ours bruns (Ursus arctos), permettent de confirmer qu’en captivitĂ©, tant les ours bruns que les ours polaires sont capables de conceptualiser l’utilisation d’un outil pour se procurer de la nourriture qui ne serait autrement pas accessible. D’après les renseignements prĂ©levĂ©s auprès de toutes nos sources, cela aurait aussi pu ĂŞtre occasionnellement le cas en milieu sauvage. Nous suggĂ©rons que l’utilisation possible d’outils par les ours polaires en milieu sauvage n’est pas frĂ©quente et qu’elle est surtout limitĂ©e Ă  la chasse au morse en raison de la grande taille de cette espèce, de la difficultĂ© Ă  l’abattre et des armes potentiellement mortelles qu’elle possède, tant pour se dĂ©fendre que pour attaquer un prĂ©dateur directement.&nbsp

    Dry-season retreat and dietary shift of the dart-poison frog Dendrobates tinctorius (Anura: Dendrobatidae)

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    A precipitação sazonal afeta a dinâmica das florestas tropicais e o comportamento das espécies que fazem parte desse ecossistema. A relação positiva entre os padrões de atividade dos anfíbios e a precipitação já foi demonstrada repetidas vezes. Os membros da família Dendrobatidae, um clado de saposvenenodeflecha neotropicais, são bemconhecidos por seu uso de hábitat e comportamento durante a estação chuvosa, mas seu comportamento durante a estação seca tem recebido pouca atenção. Estudamos o uso de hábitat e a dieta do dendrobatídeo Dendrobates tinctorius na Guiana Francesa durante as estações chuvosa e seca. Ao contrário de muitos outros dendrobatídeos, D. tinctorius não mantém territórios ao longo de toda a estação chuvosa. Ambos os sexos colonizam clareiras recentemente abertas e permanecem apenas poucas semanas nessas manchas, onde os animais consomem uma grande variedade de presas, principalmente formigas, besouros, vespas, larvas de insetos e ácaros. Durante a estação seca, os animais movem-se para locais de abrigo na floresta madura, como brácteas de palmeiras e ocos de árvores. Nesse período, são menos ativos e consomem um menor número de itens alimentares; consomem menos vespas e larvas de insetos e mais cupins. Formigas constituem a presa mais comum durante as duas estações. Discutimos os efeitos das mudanças sazonais no uso de hábitat sobre o comportamento territorial dos dendrobatídeos.Seasonal rainfall affects tropical forest dynamics and behavior of species that are part of these ecosystems. The positive correlation between amphibian activity patterns and rainfall has been demonstrated repeatedly. Members of Dendrobatidae, a clade of Neotropical dartpoison frogs, are well known for their habitat use and behavior during the rainy season, but their behavior during the dry season has received little attention. We studied habitat use and diet of the dendrobatid frog Dendrobates tinctorius in French Guiana during the rainy and dry seasons. Unlike many other dendrobatid frogs, D. tinctorius does not maintain territories for the entire rainy season. Both sexes colonize recently formed canopygaps and stay in these forest patches for only a few weeks. The frogs in these patches consume a great diversity of prey, consisting of ants, beetles, wasps, insect larvae, and mites. During the dry season, frogs move to retreat sites in mature forest, such as palm bracts and tree holes. The frogs are less active and consume fewer prey items in the dry season, and they consume fewer wasps and insect larvae, but more termites. Ants are the most common prey items during both the wet and dry seasons. We discuss the effects of shifts in seasonal habitat use on the territorial behavior of dendrobatid frogs

    Habitat Use of Ringed Seals (Phoca hispida) in the North Water Area (North Baffin Bay)

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    In conjunction with the International North Water Polynya Study in Smith Sound (northern Baffin Bay) in 1997-99, we examined the area use and diving activity of 23 ringed seals (Phoca hispida) that had been equipped with satellite transmitters on the Greenland side of the North Water (NOW) area. The study covered the period 12 August 1996-30 June 1999. Contact with the seals was maintained for an average of 108 days (range: 8-332 days). Four seals emigrated from the NOW area. During all seasons, the seals that remained in the area spent about 90% of the time in coastal (< 100 m deep) waters in the eastern parts of the NOW area. The total area visited by the seals during the open-water season ranged between 10 300 km² (1996) and 18 500 km² (1998), corresponding to about 15% to 25% of the entire NOW area. In winter, the total area visited by the seals varied between 2500 km² (1996-97) and 7000 km² (1998-99), and in spring, between 800 km² (1999) and 2100 km² (1997). Individual movement was significantly greater during the open-water season than during winter and spring. Maximum dive depths recorded were over 500 m (maximum for the instrument) outside and 376 m inside the NOW, for a 96 kg male seal. Non-adult seals spent about 99% of the time in waters less than 100 m deep, and more than 92% of the time in the upper 50 m. In contrast, adults tended to spend more time at greater depths. The study indicated that (1) the ringed seals took advantage of the generally lighter ice conditions in the eastern NOW, and (2) that non-adults likely exploited ice-associated amphipods and young polar cod (Boreogadus saida), and adults, mainly older polar cod and cephalopods taken at greater depths.Conjointement avec l'étude internationale sur la polynie de l'Eau du Nord dans le détroit de Smith (partie nord de la baie de Baffin) menée de 1997 à 1999, on a examiné l'utilisation de cette zone et l'activité de plongée de 23 phoques annelés (Phoca hispida) munis d'émetteurs-satellite du côté groenlandais de la région de l'Eau du Nord («NOW»). L'étude a couvert la période allant du 12 août 1996 au 30 juin 1999. Le contact avec les phoques a été maintenu pendant une moyenne de 108 jours (étendue: 8-332 jours). Quatre phoques ont émigré de la zone NOW. Durant toutes les saisons, les phoques qui restaient dans la zone passaient environ 90% du temps dans des eaux côtières (profondeur < 100 m) dans les secteurs orientaux de NOW. La superficie totale visitée par les phoques durant la saison d'eau libre allait de 10 300 km² (1996) à 18 500 km² (1998), correspondant à environ 15 à 25% de toute la zone NOW. En hiver, l'étendue totale fréquentée par les phoques allait de 2500 km² (1996-1997) à 7000 km² (1998-1999), et au printemps, de 800 km² (1999) à 2100 km² (1997). Les déplacements individuels étaient de beaucoup plus grands durant la saison d'eau libre qu'au cours de l'hiver et du printemps. Les profondeurs maximales de plongée enregistrées dépassaient 500 m (limite de l'instrument) à l'extérieur de la zone NOW et 376 m à l'intérieur, pour un phoque mâle de 96 kg. Les phoques non adultes passaient environ 99% du temps dans des eaux à une profondeur ne dépassant pas 100 m, et plus de 92% du temps dans les 50 m supérieurs. En revanche, les adultes avaient tendance à passer plus de temps à de plus grandes profondeurs. L'étude révèle 1) que les phoques annelés tiraient parti du fait qu'il y avait moins de glace dans la partie orientale de NOW, et 2) que, selon toute vraisemblance, les non-adultes exploitaient amphipodes et jeune morue polaire (Boreogadus saida) associés à la glace, les adultes se nourrissant surtout de morue polaire plus âgée et de céphalopodes prélevés à de plus grandes profondeurs

    Reo + mCRL2: A Framework for Model-checking Dataflow in Service Compositions

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    The paradigm of service-oriented computing revolutionized the field of software engineering. According to this paradigm, new systems are composed of existing stand-alone services to support complex cross-organizational business processes. Correct communication of these services is not possible without a proper coordination mechanism. The Reo coordination language is a channel-based modeling language that introduces various types of channels and their composition rules. By composing Reo channels, one can specify Reo connectors that realize arbitrary complex behavioral protocols. Several formalisms have been introduced to give semantics to Reo. In their most basic form, they reflect service synchronization and dataflow constraints imposed by connectors. To ensure that the composed system behaves as intended, we need a wide range of automated verification tools to assist service composition designers. In this paper, we present our framework for the verification of Reo using the toolset. We unify our previous work on mapping various semantic models for Reo, namely, constraint automata, timed constraint automata, coloring semantics and the newly developed action constraint automata, to the process algebraic specification language of , address the correctness of this mapping, discuss tool support, and present a detailed example that illustrates the use of Reo empowered with for the analysis of dataflow in service-based process models

    The Utility of Harvest Recoveries of Marked Individuals to Assess Polar Bear (Ursus maritimus) Survival

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    Management of polar bear (Ursus maritimus) populations requires the periodic assessment of life history metrics such as survival rate. This information is frequently obtained during short-term capture and marking efforts (e.g., over the course of three years) that result in hundreds of marked bears remaining in the population after active marking is finished. Using 10 additional years of harvest recovery subsequent to a period of active marking, we provide updated estimates of annual survival for polar bears in the Baffin Bay population of Greenland and Canada. Our analysis suggests a decline in survival of polar bears since the period of active marking that ended in 1997; some of the decline in survival can likely be attributed to a decline in springtime ice concentration over the continental shelf of Baffin Island. The variance around the survival estimates is comparatively high because of the declining number of marks available; therefore, results must be interpreted with caution. The variance of the estimates of survival increased most substantially in the sixth year post-marking. When survival estimates calculated with recovery-only and recapture-recovery data sets from the period of active marking were compared, survival rates were indistinguishable. However, for the period when fewer marks were available, survival estimates were lower using the recovery-only data set, which indicates that part of the decline we detected for 2003 – 09 may be due to using only harvest recovery data. Nevertheless, the decline in the estimates of survival is consistent with population projections derived from harvest numbers and earlier vital rates, as well as with an observed decline in the extent of sea ice habitat.La gestion des populations d’ours polaires (Ursus maritimus) nécessite l’évaluation périodique des mesures du cycle biologique, tel que le taux de survie. Cette information est souvent obtenue dans le cadre des efforts de capture et de marquage à court terme (par exemple, sur une période de trois ans) qui se traduisent par le marquage d’une centaine d’ours au sein de la population une fois les travaux terminés. En nous appuyant sur dix années supplémentaires de données de récoltes de reprises suivant une période de marquage actif, nous aboutissons à des estimations actualisées de la survie annuelle des ours polaires faisant partie de la population de la baie de Baffin du Groenland et du Canada. Notre analyse suggère qu’il y a eu un déclin sur le plan de la survie des ours polaires depuis la période de marquage actif qui a pris fin en 1997. Une partie de ce déclin en matière de survie peut être attribuable à la diminution de la concentration de glace printanière sur le plateau continental de l’île de Baffin. La variance entourant les estimations de survie est comparativement élevée en raison du nombre à la baisse de marquages disponibles. Il y a donc lieu de faire preuve de prudence dans l’interprétation des résultats. La variance des estimations de survie augmentait considérablement au cours de la sixième année suivant le marquage. Lorsque nous avons comparé les estimations de survie avec les ensembles de données de reprise seulement et celles de recapture et de reprise pour la période de marquage actif, les taux de survie étaient indistinguables. Cependant, pour la période pendant laquelle un moins grand nombre de marquages était disponible, les estimations de survie étaient moins élevées lorsque nous nous sommes appuyés sur l’ensemble des données de reprise seulement, ce qui indique qu’une partie du déclin que nous avons constaté pour les années 2003 à 2009 pourrait être attribuable au fait que nous n’avons utilisé que les données des récoltes de reprises. Néanmoins, le déclin en matière d’estimations de survie est conforme aux projections de population dérivées des résultats des récoltes et des indices vitaux antérieurs, ainsi qu’à la diminution qui a été observée sur le plan de l’étendue de l’habitat de la glace de mer
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