Texture and hydrodynamics of a thin slab of superfluid3He-A in a torsional oscillator. II. Experiment

Experiments on a torsional oscillator containing a slab of liquid³He of thickness 105 µm and diameter 8.38 mm are described. Normal phase experiments confirm the theory of the oscillator dynamics but an apparent descrase in the measured value of T ² at lowT casts doubt on the existing slip theory. Measurements for the uniform texture for the A phase give values of _s and ₄₄. The _s measurements suggest that the A-phase energy gap is enhanced by a factor 1.24 over the BCS value. Distortion of the uniform texture by a magnetic field perpendicular to the slab occurs at a threshold field slightly smaller than predicted. Measurements for fields at different angles to the slab enable accurate values to be deduced for the superfluid density anisotropy and two other viscosity coefficients. The remaining two viscosity coefficients are only poorly determined. Flow alignment of the orbital texture was achieved by increasing the oscillator amplitude. A different texture obtained on some occasions after warming from the B phase was investigated but is not understood.     

Techniques for pipelined broadcast on ethernet switched clusters

By splitting a large broadcast message into segments and broadcasting the segments in a pipelined fashion, pipelined broadcast can achieve high performance in many systems. In this paper, we investigate techniques for efficient pipelined broadcast on clusters connected by multiple Ethernet switches. Specifically, we develop algorithms for computing various contention-free broadcast trees that are suitable for pipelined broadcast on Ethernet switched clusters, extend the parametrized LogP model for predicting appropriate segment sizes for pipelined broadcast, show that the segment sizes computed based on the model yield high performance, and evaluate various pipelined broadcast schemes through experimentation on Ethernet switched clusters with various topologies. The results demonstrate that our techniques are practical and efficient for contemporary fast Ethernet and Giga-bit Ethernet clusters.     

Superconducting properties of zinc substitution in Tl-2223 phase

The effect of partial replacement of copper by zinc in Tl₂Ba₂Ca₂Cu₃O_10−δ superconductor phase is studied. Superconducting samples of the nominal composition Tl₂Ba₂Ca₂Cu_3−xZn_xO_10−δ with x ranging from 0 to 0.6 are prepared under normal pressure by a one step of solid-state reaction technique. The samples are characterized by using X-ray powder diffraction, scanning electron microscope (SEM) and EDX. The X-ray data indicate that the partial replacement of Cu²⁺ions by Zn²⁺ions does not influence the tetragonal structure of the samples, and the lattice parameters a and c vary according to the difference in the ionic radii of Cu and Zn. The superconducting parameters, such as superconducting transition temperature T_c, critical current density J_c and irreversibility field B_ir are calculated from electrical resistivity and AC-magnetic susceptibility measurements.     

Contingent Leadership and Effectiveness of Trauma Resuscitation Teams.

This research investigated leadership and effectiveness of teams operating in a high-velocity environment, specifically trauma resuscitation teams. On the basis of the literature and their own ethnographic work, the authors proposed and tested a contingency model in which the influence of leadership on team effectiveness during trauma resuscitation differs according to the situation. Results indicated that empowering leadership was more effective when trauma severity was low and when team experience was high. Directive leadership was more effective when trauma severity was high or when the team was inexperienced. Findings also suggested that an empowering leader provided more learning opportunities than did a directive leader. The major contribution of this article is the linkage of leadership to team effectiveness, as moderated by relatively specific situational contingencies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Soybean Isoflavones: Effects of Processing and Health Benefits

Isoflavones belong to a group of compounds known as flavanoids that share a basic structure consisting of two benzene rings linked through a heterocyclic pyrane C ring. Soybean provides the most abundant source of isoflavones, which have been linked to the prevention of several diseases, including cancer (prostate, colon, and breast cancer), hypercholesterolemia, cardiovascular disease, atherosclerosis, osteoporosis, and relief of menopausal symptoms in certain women. Currently, isoflavone use is targeted as a nutraceutical. In this article, we review the structural aspects and the effect of processing on the different forms of isoflavones in soy protein. We also discuss the impact of these changes on the health benefits of eating foods containing isoflavones. Isoflavones, as a class of phytoestrogens, are gaining a lot of interest in clinical nutrition.