15,687 research outputs found
What Helps Law Professors Develop as Teachers? -- An Empirical Study
The overall goal of this article is to provide concrete suggestions for how law schools can improve teaching and enrich law student learning. In doing so, it reviews and analyzes the data collected from two national surveys about the kinds of faculty development activities that are most effective in improving law professors’ teaching. One survey was designed to quantify how many law teachers engaged in twenty-two types of teaching development activities over the previous five years and to assess the effectiveness of each of those activities. The other survey focused on the effectiveness of a national conference on teaching and learning in law school. This article builds upon Improving Teaching and Learning in Law School: Faculty Development Research, Principles, and Programs, 12 WIDENER L. REV. 443 (2006), which presented the principles fundamental to effective faculty development programs. This article shows how these principles apply by providing data about the effectiveness of a wide range of teaching development activities
Star-shaped Local Density of States around Vortices in a Type II Superconductor
The electronic structure of vortices in a type II superconductor is analyzed
within the quasi-classical Eilenberger framework. The possible origin of a
sixfold ``star'' shape of the local density of states, observed by scanning
tunneling microscope experiments on NbSe, is examined in the light of the
three effects; the anisotropic pairing, the vortex lattice, and the anisotropic
density of states at the Fermi surface. Outstanding features of split parallel
rays of this star are well explained in terms of an anisotropic -wave
pairing. This reveals a rich internal electronic structure associated with a
vortex core.Comment: 4 pages, REVTeX, 3 figures available upon reques
Campylobacter jejuni colonization promotes the translocation of Escherichia coli to extra-intestinal organs and disturbs the short-chain fatty acids profiles in the chicken gut
For a long time Campylobacter was only considered as a commensal microorganism in avian hosts restricted to the ceca, without any pathogenic features. The precise reasons for the symptomless chicken carriers are still unknown, but investigations of the gastrointestinal ecology of broiler chickens may improve our understanding of the microbial interactions with the host. Therefore, the current studies were conducted to investigate the effects of Campylobacter jejuni colonization on Escherichia coli translocation and on the metabolic end products (short-chain fatty acids, SCFAs). Following oral infection of 14 day old broiler chickens with 1 × 108 CFU of Campylobacter jejuni NCTC 12744 in two independent animal trials, it was found that C. jejuni heavily colonized the intestine and disseminate to extra-intestinal organs. Moreover, in both animal trials, the findings revealed that C. jejuni promoted the translocation of E. coli with a higher number encountered in the spleen and liver at 14 days post infection (dpi). In addition, Campylobacter affected the microbial fermentation in the gastrointestinal tract of broilers by reducing the amount of propionate, isovalerate, and isobutyrate in the cecal digesta of the infected birds at 2 dpi and, at 7 and 14 dpi, butyrate, isobutyrate, and isovalerate were also decreased. However, in the jejunum, the C. jejuni infection lowered only butyrate concentrations at 14 dpi. These data indicated that C. jejuni may utilize SCFAs as carbon sources to promote its colonization in the chicken gut, suggesting that Campylobacter cannot only alter gut colonization dynamics but might also influence physiological processes due to altered microbial metabolite profiles.
Finally, the results demonstrated that C. jejuni can cross the intestinal epithelial barrier and facilitates the translocation of Campylobacter itself as well as of other enteric microorganisms such as E. coli to extra-intestinal organs of infected birds. Altogether, our findings suggest that the Campylobacter carrier state in chicken is characterised by multiple changes in the intestinal barrier function, which supports multiplication and survival within the host
Local density of states in the vortex lattice in a type II superconductor
Local density of states (LDOS) in the triangular vortex lattice is
investigated based on the quasi-classical Eilenberger theory. We consider the
case of an isotropic s-wave superconductor with the material parameter
appropriate to NbSe_2. At a weak magnetic field, the spatial variation of the
LDOS shows cylindrical structure around a vortex core. On the other hand, at a
high field where the core regions substantially overlap each other, the LDOS is
sixfold star-shaped structure due to the vortex lattice effect. The orientation
of the star coincides with the experimental data of the scanning tunneling
microscopy. That is, the ray of the star extends toward the nearest-neighbor
(next nearest-neighbor) vortex direction at higher (lower) energy.Comment: 10 pages, RevTex, 32 figure
The H.E.S.S. extragalactic sky
The H.E.S.S. Cherenkov telescope array, located on the southern hemisphere in
Namibia, studies very high energy (VHE; E>100 GeV) gamma-ray emission from
astrophysical objects. During its successful operations since 2002 more than 80
galactic and extra-galactic gamma-ray sources have been discovered. H.E.S.S.
devotes over 400 hours of observation time per year to the observation of
extra-galactic sources resulting in the discovery of several new sources,
mostly AGNs, and in exciting physics results e.g. the discovery of very rapid
variability during extreme flux outbursts of PKS 2155-304, stringent limits on
the density of the extragalactic background light (EBL) in the near-infrared
derived from the energy spectra of distant sources, or the discovery of
short-term variability in the VHE emission from the radio galaxy M 87. With the
recent launch of the Fermi satellite in 2008 new insights into the physics of
AGNs at GeV energies emerged, leading to the discovery of several new
extragalactic VHE sources. Multi-wavelength observations prove to be a powerful
tool to investigate the production mechanism for VHE emission in AGNs. Here,
new results from H.E.S.S. observations of extragalactic sources will be
presented and their implications for the physics of these sources will be
discussed.Comment: 8 pages, 6 figures, invited review talk, in the proceedings of the
"International Workshop on Beamed and Unbeamed Gamma-Rays from Galaxies"
11-15 April 2011, Lapland Hotel Olos, Muonio, Finland, Journal of Physics:
Conference Series Volume 355, 201
Low-lying Quasiparticle Excitations around a Vortex Core in Quantum Limit
Focusing on a quantum-limit behavior, we study a single vortex in a clean
s-wave type-II superconductor by self-consistently solving the Bogoliubov-de
Gennes equation. The discrete energy levels of the vortex bound states in the
quantum limit is discussed. The vortex core radius shrinks monotonically up to
an atomic-scale length on lowering the temperature T, and the shrinkage stops
to saturate at a lower T. The pair potential, supercurrent, and local density
of states around the vortex exhibit Friedel-like oscillations. The local
density of states has particle-hole asymmetry induced by the vortex. These are
potentially observed directly by STM.Comment: 4 pages, 6 figure
When stereopsis does not improve with increasing contrast1Portions of this work were presented at The European Conference on Visual Perception, Helsinki, 1997.1
AbstractIt is well known that stereoacuity for conventional (1st-order) stimuli improves with increasing contrast with an approximate slope of −0.5 on log–log axes (Halpern DL, Blake RR. Perception 1988;17:483–495; Legge GE, Gu Y. Vis Res 1989;29:989–1004). In the experiments reported here a variety of stimuli were used (Gabor patches, amplitude modulated stimuli and 1D noise patches) and tasks (stereoacuity and Dmax) to determine if 2nd-order stereopsis shows a similar square root dependence. The results consistently demonstrate that the effect of contrast on stereopsis is quite different for the 2nd-order stimuli. Increases in stimulus contrast have little effect on performance; the resulting slopes are very shallow. The pattern of results is similar when the interocular contrast ratio is varied, demonstrating that 2nd-order processing is more resilient to stimulus differences in the two eyes than 1st-order
Mixed-State Quasiparticle Spectrum for d-wave Superconductors
Controversy concerning the pairing symmetry of high- materials has
motivated an interest in those measurable properties of superconductors for
which qualitative differences exist between the s-wave and d-wave cases. We
report on a comparison between the microscopic electronic properties of d-wave
and s-wave superconductors in the mixed state. Our study is based on
self-consistent numerical solutions of the mean-field Bogoliubov-de Gennes
equations for phenomenological BCS models which have s-wave and d-wave
condensates in the absence of a magnetic field. We discuss differences between
the s-wave and the d-wave local density-of-states, both near and away from
vortex cores. Experimental implications for both scanning-tunneling-microscopy
measurements and specific heat measurements are discussed.Comment: 10 pages, REVTEX3.0, 3 figures available upon reques
Rare isotope studies involving catalytic oxidation of CO over platinum-tin oxide
Results of studies utilizing normal and rare oxygen isotopes in the catalytic oxidation of carbon monoxide over a platinum-tin oxide catalyst substrate are presented. Chemisorption of labeled carbon monoxide on the catalyst followed by thermal desorption yielded a carbon dioxide product with an oxygen-18 composition consistent with the formation of a carbonate-like intermediate in the chemisorption process. The efficacy of a method developed for the oxygen-18 labeling of the platinum-tin oxide catalyst surface for use in closed cycle pulsed care isotope carbon dioxide lasers is demonstrated for the equivalent of 10 to the 6th power pulses at 10 pulses per second
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