35,697 research outputs found
Elemental analyses of lunar samples by 14 MeV and thermal neutron activation Final report, period ending 31 Jan. 1971
Neutron activation analyses of lunar sample abundance
Dietary Uncoupling of Gut Microbiota and Energy Harvesting from Obesity and Glucose Tolerance in Mice
The authors gratefully acknowledge Doctoral Training Partnership funding from the BBSRC (M.J.D.) and funding from the Scottish Government (P.J.M., A.W.R., and A.W.W.). We also thank the Centre for Genome-Enabled Biology and Medicine for help with next-generation sequencing and Karen Garden and the Rowett’s Analytical Services for SCFA analysis. SUPPLEMENTAL INFORMATION Supplemental Information includes four figures and two tables and can be found with this article online at https://doi.org/10.1016/j.celrep.2017.10.056.Peer reviewedPublisher PD
Calibration of Viking imaging system pointing, image extraction, and optical navigation measure
Pointing control and knowledge accuracy of Viking Orbiter science instruments is controlled by the scan platform. Calibration of the scan platform and the imaging system was accomplished through mathematical models. The calibration procedure and results obtained for the two Viking spacecraft are described. Included are both ground and in-flight scan platform calibrations, and the additional calibrations unique to optical navigation
Thin-walled pressure vessel Patent
Thin walled pressure test vessel using low-melting alloy-filled joint to attach shell to head
Lazarus ecology: Recovering the distribution and migratory patterns of the extinct Carolina parakeet.
The study of the ecology and natural history of species has traditionally ceased when a species goes extinct, despite the benefit to current and future generations of potential findings. We used the extinct Carolina parakeet as a case study to develop a framework investigating the distributional limits, subspecific variation, and migratory habits of this species as a means to recover important information about recently extinct species. We united historical accounts with museum collections to develop an exhaustive, comprehensive database of every known occurrence of this once iconic species. With these data, we combined species distribution models and ordinal niche comparisons to confront multiple conjectured hypotheses about the parakeet's ecology with empirical data on where and when this species occurred. Our results demonstrate that the Carolina parakeet's range was likely much smaller than previously believed, that the eastern and western subspecies occupied different climatic niches with broad geographical separation, and that the western subspecies was likely a seasonal migrant while the eastern subspecies was not. This study highlights the novelty and importance of collecting occurrence data from published observations on extinct species, providing a starting point for future investigations of the factors that drove the Carolina parakeet to extinction. Moreover, the recovery of lost autecological knowledge could benefit the conservation of other parrot species currently in decline and would be crucial to the success of potential de-extinction efforts for the Carolina parakeet
Novel Dynamical Resonances in Finite-Temperature Bose-Einstein Condensates
We describe a variety of intriguing mode-coupling effects which can occur in
a confined Bose-Einstein condensed system at finite temperature. These arise
from strong interactions between a condensate fluctuation and resonances of the
thermal cloud yielding strongly non-linear behaviour. We show how these
processes can be affected by altering the aspect ratio of the trap, thereby
changing the relevant mode-matching conditions. We illustrate how direct
driving of the thermal cloud can lead to significant shifts in the excitation
spectrum for a number of modes and provide further experimental scenarios in
which the dramatic behaviour observed for the mode at JILA (Jin {\it et
al.} 1997) can be repeated. Our theoretical description is based on a
successful second-order finite-temperature quantum field theory which includes
the full coupled dynamics of the condensate and thermal cloud and all relevant
finite-size effects
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