2,412 research outputs found
No evidence of a significant role for CTLA-4 in multiple sclerosis
Variation in the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) gene plays a significant role in determining susceptibility to autoimmune thyroid disease and type 1 diabetes. Its role in multiple sclerosis is more controversial. In order to explore this logical candidate more thoroughly, we genotyped 771 multiple sclerosis trio families from the United Kingdom for the 3? untranslated region variable number tandem repeat, the CT60 single nucleotide polymorphism (SNP) and five haplotype-tagging SNPs. No individual marker or common haplotype showed evidence of association with disease. These data suggest that any effect of CTLA-4 on multiple sclerosis susceptibility is likely to be very small
Separation of lymphocytes by electrophoresis under terrestrial conditions and at zero gravity, phase 3
Electrophoretic mobilities (EPM) of peripheral lymphocytes were studied from normal subjects, chronic hemodialysis patients and kidney transplant recipients. A technique to separate B lymphocytes and null cells from non-T lymphocyte preparation was developed. The experiments were designed to determine which subpopulation of the non-T lymphocytes is primarily affected and shows a decreased EPM in chronic hemodialysis patients and kidney transplant recipients
Lithological and geochemical dispersal in till: McAdam area, New Brunswick
Analyses of dispersal patterns for till clasts and matrix geochemistry in the McAdam area, southwestern New Brunswick, are used to define the dominant glacial transport direction in an area of ice-flow complexity, as indicated by multiple and differing striae directions. Dispersal and erosional data indicate that the main (regional) southeastward flow direction was preceded and followed by secondary deviations, due to local influences of topography and substrate and possibly also from changes within the ice mass or surrounding glaciers. Clast trains are traceable from known outcrops, southward over distances greater than 16 km, whereas distinctive geochemical trains are lost within 10 km of transport, due to homogenization of the till matrix. These results demonstrate that for drift prospecting, transport path and source unit are more clearly delineated by shape and size of till clasts and matrix dispersal patterns, than by analysis of directional indicators caused by glacial erosion.
RÉSUMÉ
On a recours à des analyses des modes de dispersion des clastes du till et de la géochimie de la matrice dans le secteur de McAdam, dans le sud-est du Nouveau-Brunswick, pour défiinir la direction du transport glaciaire dominant à l’intérieur d'un secteur caractérisé par la complexity de l'écoulemcnt glaciaire, comme en témoignent les directions multiples et différentes des rayures. Les données relatives à la dispersion et à l'érosion révèlant que la principale direction (régionale) de l'écoulcment, l'écoulement vers le sud-est, a été précédée et suivie de déviations secondares en raison des influences locales de la topographie et du substrat, ainsi que possiblement de changements survenus à l'intérieur de l'amas de glaces ou des glaciers environnants. On peut retracer les parcours des clastes à partir d'affleurements connus sur des distances de plus de 16 km vers le sud, alors qu'on pcrd des tracées géochimiques distinctifs à moins de 10 km de transport à cause de l'homogénéisation de la matrice du till. Ces résultats démontrent qu'en matère de prospection glacio-sédimentaire, on délimite plus nettement le trajet du transport et l'unité d'origine par la forme et la dimension des clastes du till et par les modes de dispersion de la matrice que par l'analyse des indicateurs de direction laissés par l'érosion glaciaire.
[Traduit par la rédaction
Nonlinear Band Structure in Bose Einstein Condensates: The Nonlinear Schr\"odinger Equation with a Kronig-Penney Potential
All Bloch states of the mean field of a Bose-Einstein condensate in the
presence of a one dimensional lattice of impurities are presented in closed
analytic form. The band structure is investigated by analyzing the stationary
states of the nonlinear Schr\"odinger, or Gross-Pitaevskii, equation for both
repulsive and attractive condensates. The appearance of swallowtails in the
bands is examined and interpreted in terms of the condensates superfluid
properties. The nonlinear stability properties of the Bloch states are
described and the stable regions of the bands and swallowtails are mapped out.
We find that the Kronig-Penney potential has the same properties as a
sinusoidal potential; Bose-Einstein condensates are trapped in sinusoidal
optical lattices. The Kronig-Penney potential has the advantage of being
analytically tractable, unlike the sinusoidal potential, and, therefore, serves
as a good model for experimental phenomena.Comment: Version 2. Fixed typos, added referenc
US VAO Facility for Rapid Transients
The US VAO Facility for Rapid Transients (if funded) will collect and disseminate observations about time-critical astronomical transients, and add annotations and intelligent machine-learning to those observations. The information can be “pushed” to subscribers, who may be either humans or machines that control telescopes. Subscribers can prepare precise “triggers” to decide which events should reach them and their machines, that may be based on the generic event, or on the specific vocabulary of parameters that define a particular type of observation. The system will not be centralized, but rather a set of interoperating nodes with caching. The twin thrusts are automation of process, and discrimination of interesting events
Non Fermi Liquid Behaviour near a spin-glass transition
In this paper we study the competition between the Kondo effect and RKKY
interactions near the zero-temperature quantum critical point of an Ising-like
metallic spin-glass. We consider the mean-field behaviour of various physical
quantities. In the `quantum- critical regime' non-analytic corrections to the
Fermi liquid behaviour are found for the specific heat and uniform static
susceptibility, while the resistivity and NMR relaxation rate have a non-Fermi
liquid dependence on temperature.Comment: 15 pages, RevTex 3.0, 1 uuencoded ps. figure at the en
A mechanism for the non-Fermi-liquid behavior in CeCu_{6-x}Au_x
We propose an explanation for the recently observed non-Fermi-liquid behavior
of metallic alloys CeCu_{6-x}Au_x: near x=0.1, the specific heat c is
proportional to T \ln (T_0/T) and the resistivity increases linearly with
temperature T over a wide range of T. These features follow from a model in
which three-dimensional conduction electrons are coupled to two-dimensional
critical ferromagnetic fluctuations near the quantum critical point, x_{c}=0.1.
This picture is motivated by the neutron scattering data in the ordered phase
(x=0.2) and is consistent with the observed phase diagram.Comment: 4 pages, LaTeX, 3 figure
Perceptions of knowledge sharing among small family firm leaders: a structural equation model
Small family firms have many unique relational qualities with implications for how knowledge is passed between individuals. Extant literature posits leadership approach as important in explaining differences in knowledge-sharing climate from one firm to another. This study investigates how leadership approaches interact with family influence to inform perceptions of knowledge sharing. We utilize survey data (n = 110) from owner-managers of knowledge-intensive small family firms in Scotland. Our findings present a choice in leadership intention, contrasting organization-focused participation against family-influenced guidance. Insight is offered on the implications of this leadership choice at both organizational and familial level
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