3,475 research outputs found
Mass Natural Mortality of Walruses (Odobenus rosmarus) at St. Lawrence Island, Bering Sea, Autumn 1978
In October-November 1978, several thousand living walruses came ashore in at least four localities on St. Lawrence Island where they had not been present before in this century. They hauled out also at two other sites which they have occupied annually but in much smaller numbers. At least 537 animals died on the haulout areas at that time, and approximately 400 other carcasses washed ashore from various sources. This was by far the greatest mortality of walruses ever recorded in an event of this kind. At least 15% of the carcasses on the haulouts were aborted fetuses, 24% were 5-6-month-old calves; the others were older animals ranging in age from 1 to 37 years old. About three-fourths of the latter on the haulouts were females; in the non-haulouts areas the sex ratio was about 1:1. Forty of the best preserved carcasses were examined by necropsy. The principal cause of death was identified as extreme torsion of the cervical spine, with resultant cerebrospinal hemorrhage, apparently due to traumatization by other walruses. Nearly all of the dead were extremely lean, having less than half as much subcutaneous fat as healthy animals examined in previous years
The Value of Comparative Animal Research : Krogh’s Principle Facilitates Scientific Discoveries
There are no conflicts of interest to declare. This paper developed from the 2016 Early Career Impact Award from the Federation of Associations in Behavioral & Brain Sciences to TJS. TJS has received funding from The Leverhulme Trust. FJPE is in receipt of funding from the BBSRC (BB/M001555/1). The National Institutes of Health has funded RDF (NS 034950, NS093277, NIMH 087930), AGO (HD079573, IOS-1354760) and AMK (HD081959). BAA is an Arnold O. Beckman postdoctoral fellow.Peer reviewedPostprin
A novel two-section tunable discrete mode Fabry-PÉrot laser exhibiting nanosecond wavelength switching
A novel widely tunable laser diode is proposed and demonstrated. Mode selection occurs by etching perturbing slots into the laser ridge. A two-section device is realized with different slot patterns in each section allowing Vernier tuning. The laser operates at 1.3 mum and achieves a maximum output power of 10 mW. A discontinuous tuning range of 30 nm was achieved with a side mode suppression greater than 30 dB. Wavelength switching times of approximately 1.5 ns between a number of wavelength channels separated by 7 nm have been demonstrated
A Performance Study of Horizontally Explicit Vertically Implicit (HEVI) Time-Integrators for Non-Hydrostatic Atmospheric Models
We conduct a thorough study of different forms of horizontally explicit and
vertically implicit (HEVI) time-integration strategies for the compressible
Euler equations on spherical domains typical of nonhydrostatic global
atmospheric applications. We compare the computational time and complexity of
two nonlinear variants (NHEVI-GMRES and NHEVI-LU) and a linear variant (LHEVI).
We report on the performance of these three variants for a number of additive
Runge-Kutta Methods ranging in order of accuracy from second through fifth, and
confirm the expected order of accuracy of the HEVI methods for each
time-integrator. To gauge the maximum usable time-step of each HEVI method, we
run simulations of a nonhydrostatic baroclinic instability for 100 days and
then use this time-step to compare the time-to-solution of each method. The
results show that NHEVI-LU is 2x faster than NHEVI-GMRES, and LHEVI is 5x
faster than NHEVI-LU, for the idealized cases tested. The baroclinic
instability and inertia-gravity wave simulations indicate that the optimal
choice of time-integrator is LHEVI with either second or third order schemes,
as both schemes yield similar time to solution and relative L2 error at their
maximum usable time-steps. In the future, we will report on whether these
results hold for more complex problems using, e.g., real atmospheric data
and/or a higher model top typical of space weather applications.Comment: 36 pages, 10 figures, 2 table
Assessing the perceived value of Reflexive Groups for supporting Clergy in the Church of England
This is an Accepted Manuscript of an article published by Taylor & Francis in Mental Health, Religion and Culture on 18-7-16, available online: http://dx.doi.org/10.1080/13674676.2016.1197194Little research has been conducted to assess the effectiveness of reflexive groups in supporting clergy. For this research, eight Church of England Bishops’ Advisors for Pastoral Care and Counselling were interviewed to ascertain the value of reflexive groups. These data were analysed using a thematic analysis. Two superordinate themes emerged: Contextual issues and Benefits, along with 20 subordinate themes. An online survey, consisting of questions that came from the Bishops’ Advisors data, was then sent to reflexive group participants (n=64), to see if their experiences matched those benefits identified by the Bishops’ Advisors. The data from 37 participants was statistically analysed. The data from both sets of participants reveal that reflexive groups are psychologically beneficial to clergy. The research concludes that the implementation of reflexive groups as a way of developing self-awareness and enculturating attitudes towards resilience and self-care is important to foster psychologically and spiritually healthy practice
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