3,591 research outputs found
Prospect for room temperature tunneling anisotropic magnetoresistance effect: density of states anisotropies in CoPt systems
Tunneling anisotropic magnetoresistance (TAMR) effect, discovered recently in
(Ga,Mn)As ferromagnetic semiconductors, arises from spin-orbit coupling and
reflects the dependence of the tunneling density of states in a ferromagnetic
layer on orientation of the magnetic moment. Based on ab initio relativistic
calculations of the anisotropy in the density of states we predict sizable TAMR
effects in room-temperature metallic ferromagnets. This opens prospect for new
spintronic devices with a simpler geometry as these do not require
antiferromagnetically coupled contacts on either side of the tunnel junction.
We focus on several model systems ranging from simple hcp-Co to more complex
ferromagnetic structures with enhanced spin-orbit coupling, namely bulk and
thin film L1-CoPt ordered alloys and a monatomic-Co chain at a Pt surface
step edge. Reliability of the predicted density of states anisotropies is
confirmed by comparing quantitatively our ab initio results for the
magnetocrystalline anisotropies in these systems with experimental data.Comment: 4 pages, 2 figure
Sporadic Bovine Encephalomyelitis
The infectious agent of sporadic bovine encephalomyelitis has now been propagated for nearly three years in developing chick embryos.This has afforded a convenient method of propagation while studying the causal agent. It is interesting that during all of this time in chick embryos, which represents more than 135 passages in series, there has been no apparent variation in the character of the infectious agent. It is as pathogenic for guinea pigs and cattle as when first isolated. Failure to recognize anything in the tissues of affected animals that would indicate the exact nature of the entity which causes the disease, led to an extension of the histological study to infected chick embryos, especially their membranes and yolk sacs
Derived Demand for Fresh Cheese Products Imported into Japan
The objective of this article is to estimate the derived demand for imported fresh cheese products into Japan when fresh cheese import data are disaggregated by source country of production. We provide empirical measures of the sensitivity of demand to changes in total imports, own-price, and cross-prices among exporting countries for fresh cheese. Japan's derived demand for U.S. fresh cheese products is perfectly inelastic. Thus, the import demand competition among importing countries should be based upon differences in product characteristics.Demand and Price Analysis, International Relations/Trade,
Reaching Out to the Underserved: More Than Thirty Years of Outreach Job Ads
Content of outreach position announcements posted in College and Research Libraries News from 1970 through 2004 were examined. Ads fell within three broad groups: distance education, multicultural services, and specialized. Overall, outreach positions have been on the rise with the exception of multicultural services librarian positions which have not increased at a stable rate
Geology and ground-water resources of the island of Oahu, Hawaii
Prepared in cooperation with the U.S. Geological survey.Bibliographical footnotes
Geology of the Hawaiian islands
Prepared in cooperation with the Geological Survey, United States Department of the Interior.Includes bibliographical references (pages 100-101) and index
Flow dynamics of Byrd Glacier, East Antarctica
This is the published version. Copyright 2014Force-balance calculations on Byrd Glacier, East Antarctica, reveal large spatial variations in the along-flow component of driving stress with corresponding sticky spots that are stationary over time. On the large scale, flow resistance is partitioned between basal (∼80%) and lateral (∼20%) drag. Ice flow is due mostly to basal sliding and concentrated vertical shear in the basal ice layers, indicating the bed is at or close to the pressure-melting temperature. There is a significant component of driving stress in the across-flow direction resulting in nonzero basal drag in that direction. This is an unrealistic result and we propose that there are spatial variations of bed features resulting in small-scale flow disturbances. The grounding line of Byrd Glacier is located in a region where the bed slopes upward. Nevertheless, despite a 10% increase in ice discharge between December 2005 and February 2007, following drainage of two subglacial lakes in the catchment area, the position of the grounding line has not retreated significantly and the glacier has decelerated since then. During the speed-up event, partitioning of flow resistance did not change, suggesting the increase in velocity was caused by a temporary decrease in basal effective pressure
Parasite infections in a social carnivore: Evidence of their fitness consequences and factors modulating infection load
There are substantial individual differences in parasite composition and infection load in wildlife populations. Few studies have investigated the factors shaping this heterogeneity in large wild mammals or the impact of parasite infections on Darwinian fitness, particularly in juveniles. A host's parasite composition and infection load can be shaped by factors that determine contact with infective parasite stages and those that determine the host's resistance to infection, such as abiotic and social environmental factors, and age. Host–parasite interactions and synergies between coinfecting parasites may also be important. We test predictions derived from these different processes to investigate factors shaping infection loads (fecal egg/oocyte load) of two energetically costly gastrointestinal parasites: the hookworm Ancylostoma and the intracellular Cystoisospora, in juvenile spotted hyenas (Crocuta crocuta) in the Serengeti National Park, in Tanzania. We also assess whether parasite infections curtail survival to adulthood and longevity. Ancylostoma and Cystoisospora infection loads declined as the number of adult clan members increased, a result consistent with an encounter‐reduction effect whereby adults reduced encounters between juveniles and infective larvae, but were not affected by the number of juveniles in a clan. Infection loads decreased with age, possibly because active immune responses to infection improved with age. Differences in parasite load between clans possibly indicate variation in abiotic environmental factors between clan den sites. The survival of juveniles (<365 days old) to adulthood decreased with Ancylostoma load, increased with age, and was modulated by maternal social status. High‐ranking individuals with low Ancylostoma loads had a higher survivorship during the first 4 years of life than high‐ranking individuals with high Ancylostoma loads. These findings suggest that high infection loads with energetically costly parasites such as hookworms during early life can have negative fitness consequences
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