7 research outputs found

    Phylogenomics of the genus Tursiops and closely related Delphininae reveals extensive reticulation among lineages and provides inference about eco-evolutionary drivers

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    Phylogeographic inference has provided extensive insight into the relative roles of geographical isolation and ecological processes during evolutionary radiations. However, the importance of cross-lineage admixture in facilitating adaptive radiations is increasingly being recognised, and suggested as a main cause of phylogenetic uncertainty. In this study, we used a double digest RADseq protocol to provide a high resolution (āˆ¼ 4 Million bp) nuclear phylogeny of the Delphininae. Phylogenetic resolution of this group has been especially intractable, likely because it has experienced a recent species radiation. We carried out cross-lineage reticulation analyses, and tested for several sources of potential bias in determining phylogenies from genome sampling data. We assessed the divergence time and historical demography of T. truncatus and T. aduncus by sequencing the T. aduncus genome and comparing it with the T. truncatus reference genome. Our results suggest monophyly for the genus Tursiops, with the recently proposed T. australis species falling within the T. aduncus lineage. We also show the presence of extensive cross-lineage gene flow between pelagic and European coastal ecotypes of T. truncatus, as well as in the early stages of diversification between spotted (Stenella frontalis; Stenella attenuata), spinner (Stenella longirostris), striped (Stenella coeruleoalba), common (Delphinus delphis), and Fraserā€™s (Lagenodelphis hosei) dolphins. Our study suggests that cross-lineage gene flow in this group has been more extensive and complex than previously thought. In the context of biogeography and local habitat dependence, these results improve our understanding of the evolutionary processes determining the history of this lineage

    Mars Balloon Flight Test Results

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    This paper describes a set of four Earth atmosphere flight test experiments on prototype helium superpressure balloons designed for Mars. Three of the experiments explored the problem of aerial deployment and inflation, using the cold, low density environment of the Earth's stratosphere at an altitude of 30-32 km as a proxy for the Martian atmosphere. Auxiliary carrier balloons were used in three of these test flights to lift the Mars balloon prototype and its supporting system from the ground to the stratosphere where the experiment was conducted. In each case, deployment and helium inflation was initiated after starting a parachute descent of the payload at 5 Pa dynamic pressure, thereby mimicking the conditions expected at Mars after atmospheric entry and high speed parachute deceleration. Upward and downward looking video cameras provided real time images from the flights, with additional data provided by onboard temperature, pressure and GPS sensors. One test of a 660 cc pumpkin balloon was highly successful, achieving deployment, inflation and separation of the balloon from the flight train at the end of inflation; however, some damage was incurred on the balloon during this process. Two flight tests of 12 m diameter spherical Mylar balloons were not successful, although some lessons were learned based on the failure analyses. The final flight experiment consisted of a ground-launched 12 m diameter spherical Mylar balloon that ascended to the designed 30.3 km altitude and successfully floated for 9.5 hours through full noontime daylight and into darkness, after which the telemetry system ran out of electrical power and tracking was lost. The altitude excursions for this last flight were +/-75 m peak to peak, indicating that the balloon was essentially leak free and functioning correctly. This provides substantial confidence that this balloon design will fly for days or weeks at Mars if it can be deployed and inflated without damage

    Breakthrough in Mars balloon technology

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    At the end of 1997, JPL initiated the Mars Balloon Validation Program (MABVAP) to develop and validate the technology needed for a Mars balloon mission. The main focus of MABVAP was to develop and to test a viable concept for the Martian balloon that could be implemented on the small-scale dedicated or piggy-back mission

    Conflict Associated with Decisions to Limit Life-Sustaining Treatment in Intensive Care Units

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    OBJECTIVE: To determine the incidence and nature of interpersonal conflicts that arise when patients in the intensive care unit are considered for limitation of life-sustaining treatment. DESIGN: Qualitative analysis of prospectively gathered interviews. SETTING: Six intensive care units at a university medical center. PARTICIPANTS: Four hundred six physicians and nurses who were involved in the care of 102 patients for whom withdrawal or withholding of treatment was considered. MEASUREMENTS: Semistructured interviews addressed disagreements during life-sustaining treatment decision making. Two raters coded transcripts of the audiotaped interviews. MAIN RESULTS: At least 1 health care provider in 78% of the cases described a situation coded as conflict. Conflict occurred between the staff and family members in 48% of the cases, among staff members in 48%, and among family members in 24%. In 63% of the cases, conflict arose over the decision about life-sustaining treatment itself. In 45% of the cases, conflict occurred over other tasks such as communication and pain control. Social issues caused conflict in 19% of the cases. CONCLUSIONS: Conflict is more prevalent in the setting of intensive care decision making than has previously been demonstrated. While conflict over the treatment decision itself is most common, conflict over other issues, including social issues, is also significant. By identifying conflict and by recognizing that the treatment decision may not be the only conflict present, or even the main one, clinicians may address conflict more constructively
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