Indium foil with beryllia washer improves transistor heat dissipation

Indium foil, used as an interface material in transistor mountings, greatly reduces the thermal resistance of beryllia washers. This method improves the heat dissipation of power transistors in a vacuum environment

Kinetic resolution of racemic {alpha}-olefins with ansa-zirconocene polymerization catalysts: Enantiomorphic site vs. chain end control

Copolymerization of racemic {alpha}-olefins with ethylene and propylene was carried out in the presence of enantiopure C1-symmetric ansa metallocene, {1,2-(SiMe2)2({eta}5-C5H-3,5-(CHMe2)2)({eta}5-C5H3)}ZrCl2 to probe the effect of the polymer chain end on enantioselection for the R- or S-{alpha}-olefin during the kinetic resolution by polymerization catalysis. Copolymerizations with ethylene revealed that the polymer chain end is an important factor in the enantioselection of the reaction and that for homopolymerization, chain end control generally works cooperatively with enantiomorphic site control. Results from propylene copolymerizations suggested that chain end control arising from a methyl group at the beta carbon along the main chain can drastically affect selectivity, but its importance as a stereo-directing element depends on the identity of the olefin

The coordination chemistry of saturated molecules

Our understanding of bonding in transition metal complexes, as well as our ability to use that understanding in the synthesis and application of new species, has evolved over the last 100 years; and in some sense this special feature on the coordination chemistry of saturated molecules may be considered to represent its culmination. The nature of complexes between transition metal ions and neutral molecules such as ammonia was first correctly described by Werner around the beginning of the 20th century. Interpretations in terms of electronic bonding theories followed soon after. The key feature, of course, is the availability of a low-energy filled "lone pair" orbital available for donation to a vacant orbital on the electron-accepting metal ion

Circular 87

High rates of female breeding success and offspring survival are the two major factors in productivity of any commercial livestock industry. To im prove breeding success and offspring survival, the herd m anager will establish selection criteria and choose which males and females will breed. The genetics or characteristics of future animals will reflect their parentage. Selection pressure is evident in both wild and captive populations of herbivores. Predators, environment, and human harvest strategies are a few forces which influence the characteristics of freeranging populations of reindeer, caribou, moose, wapiti, etc. In livestock production systems, herd managers often breed for specific characteristics such as larger body size, high birth and growth rates, leanness, etc. A single color or combination of colors has been another characteristic often selected by purebred cattle producers as well as reindeer herders

(dme)MCl_3(NNPh_2) (dme= dimethoxyethane; M= Nb, Ta): A Versatile Synthon for [Ta═NNPh_2] Hydrazido(2-) Complexes

Complexes (dme)TaCl_3(NNPh_2) (1) and (dme)NbCl_3(NNPh_2) (2) (dme =1,2-dimethoxyethane) were synthesized from MCl5 and diphenylhydrazine via a Lewis-acid assisted dehydrohalogenation reaction. Monomeric 1 has been characterized by X-ray, IR, UV−vis, ^(1)H NMR, and ^(13)C NMR spectroscopy and contains a κ^(1)-bound hydrazido(2-) moiety. Unlike the corresponding imido derivatives, 1 is dark blue because of an LMCT that has been lowered in energy as a result of an N_(α)−N_(β) antibonding interaction that raises the highest occupied molecular orbital (HOMO). Reaction of 1 with a variety of neutral, mono- and dianionic ligands generates the corresponding ligated complexes retaining the κ^(1)-bound [Ta−NNPh_2] moiety

Review of economic evidence in the prevention and early detection of colorectal cancer.

This paper aims to systematically review the cost-effectiveness evidence, and to provide a critical appraisal of the methods used in the model-based economic evaluation of CRC screening and subsequent surveillance. A search strategy was developed to capture relevant evidence published 1999-November 2012. Databases searched were MEDLINE, EMBASE, National Health Service Economic Evaluation (NHS EED), EconLit, and HTA. Full economic evaluations that considered costs and health outcomes of relevant intervention were included. Sixty-eight studies which used either cohort simulation or individual-level simulation were included. Follow-up strategies were mostly embedded in the screening model. Approximately 195 comparisons were made across different modalities; however, strategies modelled were often simplified due to insufficient evidence and comparators chosen insufficiently reflected current practice/recommendations. Studies used up-to-date evidence on the diagnostic test performance combined with outdated information on CRC treatments. Quality of life relating to follow-up surveillance is rare. Quality of life relating to CRC disease states was largely taken from a single study. Some studies omitted to say how identified adenomas or CRC were managed. Besides deterministic sensitivity analysis, probabilistic sensitivity analysis (PSA) was undertaken in some studies, but the distributions used for PSA were rarely reported or justified. The cost-effectiveness of follow-up strategies among people with confirmed adenomas are warranted in aiding evidence-informed decision making in response to the rapidly evolving technologies and rising expectations

Swath Mapping on the Continental Shelf and Slope: The Eel River Basin, Northern California

First Paragraph The STRATAFORM program sponsored by the Office of Naval Research (Nittrouer and Kravitz, 1996, this issue) seeks to understand how sedimentary processes lead to the formation of the stratigraphic sequences on continental margins. A central challenge facing this effort is to understand the transport of sediments in shore-parallel as well as shore-perpendicular directions• Multidimensionality is necessary to describe, for example, the accumulation of sediments from river inputs, the distribution of gullies and canyons on the slope, the meandering of channels, and the structure of slumps and slides

Reforming Public School Systems Through Sustained Union-Management Collaboration

Presents case studies of sustained collaboration between teachers' unions and management in school reform; common elements in initiating events, strategic priorities, supportive system infrastructure, and sustaining factors; and lessons learned