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The measurement of “chemical shift,” that is, the change in energy of an element's x-ray emission lines with the state of its chemical combination, has been carried out for some years. Of the three major aspects of the technique, two have received major attention. Nagel (1) has an excellent treatise on the interpretation of valence band x-ray spectra, while such workers as Fischer (2) and Koffman and Moll (3) have attempted to correlate the data with structure. The third area, convenient data collection, has not been so well investigated. Much, but not all, of the effort has been toward direct electron excitation with its attendant problems of sample damage due to high vacuum and electron bombardment effects.
A method for inducing primary nutritional ketosis in dairy cattle was developed in order to evaluate a novel technique for the monitoring of the development of ketosis through to clinical disease state. Six freshly calved, multiparous Holstein-Friesian cows were given a 500 g/kg crude protein pellet in small but frequent meals through an out-of-parlour feeder in conjunction with an allowance of grass silage restricted to 20 kg wet weight per day. Development of the disease was monitored through clinical signs, body condition scoring, weight change measures and metabolic profiling of plasma samples with particular reference to beta-hydroxybutyrate, non-esterified fatty acid and glucose levels. Four animals within the disease model group became clinically ketotic with the remaining two animals showing signs of subclinical ketosis. A further four newly calved cows, which were maintained on a normal production ration to act as a control group, did not develop signs of ketosis.
Polarimetry of the far infrared emission from magnetically-aligned interstellar grains is one of the best ways of studying the magnetic field at the Galactic center. We describe the HAWC+ instrument, under development for flight on SOFIA starting in 2015, which will provide a major advance in capability for these critically important measurements.
Polarimetry at far-infrared wavelengths is a key tool for studying physical processes on size scales ranging from interstellar dust grains to entire galaxies. A multi-wavelength continuum polarimeter at these wavelengths will allow studies of thermal dust polarization in an effort to constrain the grains’ physical properties and test grain alignment theory. High spatial resolution (5–30 arcsec) and sensitive observations will measure the influence of magnetic fields on infrared cirrus clouds, the envelopes and disks of YSOs, outflows from both low- and high-mass star forming regions, and the relative strength of magnetic, gravitational, and turbulent effects in star- and cloud-formation.
Particle bed reactors (PBRs) are being developed for both space power and propulsion applications. These reactors operate with exhaust gas temperatures in the range of 2500 to 3000 K and fuel temperatures which may be hundreds of degrees higher. One fuel design for these reactors consists of uranium carbide encapsulated in either carbon or graphite. This fuel kernel must be protected from the coolant gas, usually H2, both to prevent attack of the kernel and to limit fission product release. Refractory carbide coatings have been proposed for this purpose. The typical coating process used for this is a chemical vapor deposition. Testing of other components have indicated the superiority of refractory carbide coatings applied using a chemical vapor reaction (CVR) process, however technology to apply these coatings to large numbers of fuel particles with diameters on the order of 500 gim were not readily available.
A process to deposit these CVR coatings on surrogate fuel consisting of graphite particles is described. Several types of coatings have been applied to the graphite substrate. These include NbC in various thicknesses and a bilayer coating consisting of NbC and TaC with a intermediate layer of pyrolytic graphite. These coated particles have been characterized prior to test and the results of this characterization will be presented.
Preferred conditions for deposition of thick α-Si3 N4 plate from HSiCl3 -NH3-H2 on the vertical surfaces of a lowpressure, hot-wall CVD reactor were identified by means of a designed experiment. The design included the range of temperatures 1300°C-1500°C, pressures 0.5–2.0 Torr, and residence times 0.01–1.0 sec. The vertical deposition surfaces received a viscous, laminar flow of well mixed, thermally equilibrated reactants. Plates 0.05–0.5 mm thick were produced on multiple vertical substrates 350 cm2 in area at deposition rates 5–70 μm/hr. Plates 0.5–4.0 mm thick were produced on horizontal substrates at deposition rates of 60–120 μm/hr. When NH3 flows in stoichiometric excess, deposition rates on vertical surfaces increase approximately linearly with the flow rate of HSiCl3 but depend little on temperature, as would be expected if the reaction proceeds under mass transport control with product depletion. Multiple correlation analyses show that thickness variations in the deposit are reduced by increasing the temperature and decreasing the gas residence time. CVD silicon nitride plate produced under the optimized conditions exhibits theoretical density and is free of pores and cracks. It exhibits a columnar morphology in which the <222> and <101> crystallographic directions are oriented preferentially normal to a surface, which consists of well-defined trigonal facets 10–50 μm across. Crystallite sizes determined by Xray line broadening range from 0.06–1.0 μm. This CVD plate is gray and contains approximately 0.5 w/o C and 0.5 w/o 0 as principal impurities.
Although pneumonia is a leading cause of death from infectious disease worldwide, comprehensive information about its causes and incidence in low- and middle-income countries is lacking. Active surveillance of hospitalized patients with pneumonia is ongoing in Thailand. Consenting patients are tested for seven bacterial and 14 viral respiratory pathogens by PCR and viral culture on nasopharyngeal swab specimens, serology on acute/convalescent sera, sputum smears and antigen detection tests on urine. Between September 2003 and December 2005, there were 1730 episodes of radiographically confirmed pneumonia (34·6% in children aged <5 years); 66 patients (3·8%) died. A recognized pathogen was identified in 42·5% of episodes. Respiratory syncytial virus (RSV) infection was associated with 16·7% of all pneumonias, 41·2% in children. The viral pathogen with the highest incidence in children aged <5 years was RSV (417·1/100 000 per year) and in persons aged ⩾50 years, influenza virus A (38·8/100 000 per year). These data can help guide health policy towards effective prevention strategies.
Arctic and temperate strains of Hebeloma spp. were grown
in axenic culture on glutamic acid, alanine, lysine and NH4+
sources of nitrogen (N), with excess carbon (C) or deficient C (supplied
as glucose). Their ability to utilize seed protein as a natural
N source was also assessed. All strains tested had the capacity to assimilate
amino acids and generally utilized alanine and glutamic
acid more readily than NH4+. Some strains were able
to utilize amino C when starved of glucose C, and could mineralize amino-N
to NH3-N. Arctic strains, in particular, appeared to be pre-adapted
to the utilization of seed protein N and glutamic acid N, which is
often liberated in high concentrations after soil freezing. The results
are discussed in relation to their possible ecological importance.
A totally deaf with a multiple-channel cochler prosthesis obtained open-set speech discrimation using the telephone. CID Everyday Sentences were presented by telephone to the patient. Who repeated an average of 21 percent when a repeat of the sentences was permitted. This result is consistent with the patient's reports of telephone usage.
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