The spatial distribution and spectral characteristics of field-induced electron emission sites on broad-area high voltage electrodes

Instrumental techniques are described for displaying (a) the spatial distribution of field emission sites on planar high voltage electrodes and (b) the emission current pattern within an individual site. Typically, emission ‘sites‘ are generally composed of three or more ‘sub-sites’ that become temporally unstable at current > 10^?7 A. The electron energy spectra of sub-sites are characteristically single peaked, whose half-widths (FWHM) initially vary linearly with applied field: from changes in spectral area with field, substantially linear sub-site F-N plots have been obtained having β values in the range 300–500.     

A comparison of commonly used hydrologic design methods for rainwater collectors

Rainwater collection as a possible water source in developing countries is introduced. The major parameters in calculating the size of the tank are defined. Six methods that have been used previously to relate demand, storage, reliability and the rainfall pattern are compared to the Ottawa Model over a wide range of demands.     

Field-induced electron emission from broad-area YBaCuO high-T c electrodes

A transparent anode facility has been used to compare the field-induced electron emission characteristics of planar YBaCuO high-T _c electrodes at room temperature and in the superconducting state. It was found that virgin electrodes under ambient conditions exhibit an initial current switch-on event at typical field levels of 30 MV m^–1, with the emission coming from a single point site: a large hysteresis effect was also observed when the field was cycled. In contrast, at low temperatures, no switch-on events were observed, and the hysteresis effect was significantly smaller. Also, if an emission current in the nanoamp range was recorded under constant-field conditions as the temperature was lowered through T _c, there was an abrupt (i.e. step-like) fall in both the emission current and its associated noise at the superconducting transition.     

Infant feeding practices in St. Vincent and factors which affect them

A survey was conducted in the summer of 1975 in 2 towns in St. Vincent--Layou and Georgetown--in the effort to obtain information regarding infant feeding practices and some of the factors which may influence them. Mothers of children from 1-2 years of age were interviewed in their homes. Complete data sets were obtained on 192 of the 216 eligible children in the 2 towns. For most children the period of exclusive breastfeeding (no other milk product given) was very short. About 1/2 of the children had received milk by 2 weeks of age, and 75% by 1 month. This was followed by a much longer period of "mixed" feeding--both breast and bottle--until breastfeeding was stopped at a median age of 6.8 months. Many types of milk were used for infant feeding. For 73% of the infants, infant formula was the 1st type of milk given. This was commonly replaced by a "heavier" full cream powdered milk at a few months of age. Prelacteal feeds were very common, predominantly glucose water. "Tonics," often consisting of vitamin preparations, were another common supplement during the early months of life. Among solid foods, arrowroot, "custard," and commercial infant cereals were the first to be introduced. Relatively inexpensive locally bagged staple foods and milk powders were available in both towns, but most mothers relied heavily on packaged brand name products for infant feeding even though the cost was 2-10 times higher. It was not possible to pinpoint the exact causes for the high levels of bottle feeding, nor for the possible recent decline in breastfeeding, but several important factors were identified. Part of the problem appeared to be due to poor health and nutritional status of the mothers. In addition, in several cases the mothers reported that they had wanted to continue breastfeeding but had received no support from health professionals, and in a few instances had been ordered to stop for seemingly trivial medical reasons.     

High-speed imaging of the pulsed-field flashover of an aluminaceramic in vacuum

An intensified high-speed imaging technique was used to observe the optical events associated with the pulsed-field breakdown of an alumina ceramic tube having two concentric planar electrodes metalized onto its end face. HV pulses, typically of 5 kV amplitude (5 kV μs ^-1 rate of rise), were applied to the radial MIM insulator-electrode regime under ultrahigh vacuum (pressure <5×10^-7 Pa), with video recordings made at 1000 frames per second. Images of the observed breakdown phenomena are presented, viewed both along the center axis and also in the plane of the MIM structure. These breakdown images are discussed in relation to plasma jets associated with vacuum arcs and, in particular, on the nature of the ion species within such jets     

Transduction of full-length TAT fusion proteins into mammalian cells: TAT-p27Kip1 induces cell migration

Human procathepsin L has been expressed in E. coli in the form of inclusion bodies. The recombinant protein was isolated, refolded and processed at pH 5.5 by the addition of dextran sulfate which increased the overall yield of cathepsin L almost 10-fold. After the auto-activation of the 38 kDa procathepsin L at least three processing sites were determined by N-terminal amino acid sequencing. After replacing the Ala205 residue by glutamic acid, cathepsin B-like specificity was introduced into cathepsin L. This mutation resulted in a 15-fold increased activity toward the substrate Z-Arg-Arg-AMC and in a 29-fold decreased activity toward Z-Phe-Arg-AMC. Residue 205 is thereby confirmed experimentally to be critical for the specificity of cathepsins B and L.     

The relevance of behavioral criteria developed from the critical incident technique.

Behavioral criteria were examined for reliability and relevance. The performance of 300 pulpwood producers (of whom 150 were used for cross-validation purposes) on 8 behavioral categories was observed by foresters and dealers. The intercorrelations among the category scores were relatively low, indicating that the criteria were moderately resistant to the halo error. The relevance of the criteria to cost related measures was empirically demonstrated using multiple regression techniques. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Needed research on the interactions of certain parasitic diseases and nutrition in humans

For the purpose of assigning priorities for research, each of the following parasitic disease is examined in regard to its affect on the nutritional status of the host: schistosomiasis, malaria, amebiasis, giardiasis, ascariasis, and hookworm. The epidemiology, diagnosis, immune response to, and available therapies for these diseases are discussed. It is suggested that highest priority be given to three diseases: hookworm, ascariasis, and schistosomiasis, because they can be treated successfully, diagnosed easily, and have a high prevalence.     

In vitro iontophoretic release of lithium chloride and lidocaine hydrochloride from polymer electrolytes

Ionically conducting polymers, frequently known as polymer electrolytes, are potential candidates as hosts for drugs to be delivered iontophoretically. The iontophoretic delivery of lithium or lidocaine from polymer electrolyte films through a cellophane membrane was examined using different delivery current regimes. Thin, mechanically strong, polymer electrolyte films were fabricated from poly(ethylene oxide) (PEO) with lithium chloride or lidocaine hydrochloride. Experiments showed that iontophoretic transport of both lithium chloride and lidocaine hydrochloride might be achieved from these PEO-based films. Cation transport number determinations give values for PEO-based films of about 0.4 for lithium chloride systems and 0.12 for lidocaine hydrochloride systems. The mechanism of transport from these PEO-based polymer electrolyte films allows the delivery of ionic salts such as lithium chloride and lidocaine hydrochloride to be controlled solely by current, thus providing a system that can deliver precise amounts of drug.     

Factors explaining why people join, remain in, or leave a scholarly society: The Canadian Psychological Association.

Both theory and subject matter experts were used to generate items for a survey designed to increase understanding of why psychologists join, remain in, or leave the Canadian Psychological Association (CPA). The subject matter experts included current, former, and nonmember psychologists. 2,200 questionnaires were distributed by e-mail, and 275 were sent by surface mail. The response rates were 20% and 29% for e-mail and surface mail, respectively. Principal components analysis of the survey items resulted in 5 factors: outcomes, advocacy, organizational justice, annual convention, and professional recognition. Discriminant function analysis results showed that, on the basis of these factors, the authors were able to correctly classify respondents as current vs former members, and current vs never been members. Current members, former members, and psychologists who never joined CPA were found to differ significantly on their rating of most factors. The factors relevant for retaining members differ from those that attract psychologists to join CPA. (PsycINFO Database Record (c) 2010 APA, all rights reserved)