Drug use among young adults: The impacts of role status and social environment.

Using panel analyses, the authors examined drug use during the 1st 3 yrs following high school (HS), a period during which many young people make important transitions in social environments, primary activity, and marital status. Drug use after HS was highly predictable from senior-year drug use; however, usage rates for alcohol, marihuana, and other illicit drugs (but not cigarettes) also seemed to be influenced by post-HS living arrangements. More specifically, those who continued to live with their parents showed little or no change in their drug use. Among those who moved out of the parental home, Ss who married showed a decrease in use, those living with a partner of the opposite sex showed some increase in drug use, and those who entered other living arrangements (including dormitories) also showed an increase in use. These relations were largely unaffected by the inclusion of student status, employment status, and other predictor dimensions. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design and process considerations for fabricating RF MEMS switches on printed circuit boards

Design considerations and process development for fabricating radio frequency microelectromechanical systems (RF MEMS) switches on microwave laminate printed circuit boards (PCBs) are presented in details in this work. Two key processes, high-density inductively coupled plasma chemical vapor deposition (HDICP CVD) for low-temperature silicon nitride deposition, and compressive molding planarization (COMP) have been developed for fabricating RF MEMS switches on PCB. The effects of process conditions of HDICP CVD on low-temperature nitride film are fully characterized for its use in RF MEMS switches on PCB. Not only can COMP planarize the surface of the photoresist for lithographic patterning over topologically complex surfaces, but also simultaneously create a membrane relief pattern on the surface of a MEMS structure. Several membrane-type capacitive switches have been fabricated showing excellent RF performance and dynamic responses similar to those on semiconductor substrates. This technology promises the potential of enabling further monolithic integration of switches with other RF components, such as antennas, microwave monolithic integrated circuits (MMICs), phase shifters, tunable filters, and transmission lines on the same PCBs reducing the losses due to impedance mismatching from components/system assembly and simplifies the design of the whole RF system. [1416].     

Effects of deferred payment and fare manipulations on urban bus ridership.

152 Ss were exposed to various economic incentives designed to promote bus ridership and to corresponding reductions in automobile driving. The frequency of bus riding and the number of miles driven were recorded during 3-wk baseline, 4-wk treatment, and 2-wk follow-up periods. Following baseline, Ss were randomly assigned to one of the following conditions: (a) no treatment control; (b) credit only, where credit slips allowed Ss to board the bus without paying and be billed the full fare later; (c) credit plus inverted fare, where Ss were billed for half the fare if they rode the bus frequently: (d) credit plus differential fare, where Ss were billed for half the fare if they rode the bus during off-peak hours; and (e) free tickets, where Ss were not billed for bus rides. Results show that the groups did not differ in bus ridership during baseline or follow-up periods. In contrast, during treatment, Ss in the credit plus inverted fare and the free-tickets groups displayed significant increases in ridership. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Invited review: bovine studies on optimal lengths of dry periods

Milk production per cow has increased as a result of progressive changes in the genetics and management of the dairy animal population. A management constant during many decades of progress has been the widely adopted dry period length of 51 to 60 d. The scientific basis for that industry standard was examined to assess its validity as the appropriate standard for the modern dairy industry. If subsequent milk yields can be sustained fully after dry periods that are shorter than the current standard, then considerable milk is being forfeited by retaining longer dry periods. Conversely, failure to allow any dry period will result in a significant decrease in subsequent milk synthesis and secretion. Most studies to determine the minimum length of dry period required have involved retrospective analyses of observational data. Only five experiments have been reported in which dairy cows were assigned, at random, to planned 30- and 60-d dry periods. Estimates of the change in subsequent milk production when days dry were decreased from 50 to 57 d to 30 to 34 d ranged from a 10% decrease to a 1% increase. However, lower yields after shorter dry periods may be partially offset by greater milk yields in the previous lactation if such cows are milked 3 to 4 wk longer. Environmental factors that influence milk production as well as the biological processes that occur within the mammary gland during the nonlactating period must be considered when dry period lengths are compared. Importantly, additional animal trials that specifically assign cows randomly to the dry period lengths to be evaluated are needed to determine optimal dry period lengths for modern dairy cows in differing management scenarios.     

Computational efficiency of number-theoretic-transform-implemented finite-impulse-response filters

The computational merits of using number-theoretic transforms to spectrally implement f.i.r. filters are discussed. It is demonstrated for all but low-tap filters that the spectral method can significantly reduce the multiply load and modestly reduce the add load by comparison with the usual time-domain method and the recursive `moving-window? finite-field spectral method.     

Surface-directed, graft polymerization within microfluidic channels

We demonstrate a simple procedure to coat the surfaces of enclosed PDMS microchannels by UV-mediated graft polymerization. In prior applications, only disassembled channels could be coated by this method. This limited the utility of the method to coatings that could easily and tightly seal with themselves. By preadsorbing a photoinitiator onto the surface of PDMS microchannels, the rate of polymer formation at the surface was greatly accelerated compared to that in solution. Thus, a gel did not form in the lumen of enclosed microchannels. We demonstrate that the photoinitiator benzophenone remained on the surface of PDMS even after extensive washing. After addition of a variety of monomer solutions (acrylic acid, poly(ethylene glycol) monomethoxyl acrylate, or poly(ethylene glycol) diacrylate) and illumination with UV light, a stable, covalently attached surface coating formed in the microchannels. The electroosmotic mobility was stable in response to air exposure and to repeated cycles of hydration-dehydration of the coating. These surfaces also supported the electrophoretic separation of two model analytes. Placement of an opaque mask over a portion of the channel permitted photopatterning of the microchannels with a resolution of approximately 100 microm. By using an appropriate mixture of monomers combined with masks, it should be possible to fabricate PDMS microfluidic devices with distinct surface properties in different regions or channels.     

Effect of Gamma Irradiation on Whole-cell Glucose Isomerase. Part 2. Properties of Irradiated Whole-cell Glucose Isomerase

Several properties of Actinoplanes missouriensis and Streptomyces olivaceus glucose isomerase have been studied after irradiation the enzyme of the dose of 10 kGy in dry state. The temperature at which the Actinoplanes missouriensis cells show the highest activity decreased by at least five centigrades. Other investigated enzymatic properties have been found to show no significant differences after irradiation.     

Effect of a synthetic corticoid on milk yield and composition and on blood metabolites and hormones in dairy cows.

Twenty-five dairy cows were assigned randomly by breed to flumethasone treatment (10 mug/day, 13 cows) or placebo control (12 cows) from 4 to 44 wk of lactation. Lactation means and trends with stage of lactation were treatment responses. Mean milk yields of cows supplemented with flumethasone were not significantly different from controls. Mean metabolite (glucose, nonesterified fatty acids, and total esterified fatty acids) and hormone concentrations (corticoids, insulin, and prolactin) of blood plasma and their trends throughout lactation were unaffected by supplementation. Data were pooled to determine effects of stage of lactation, temperature, pregnancy, and month on these variables. Changes during lactation were systematic for feed intake, body weight, milk yield, milk components except somatic cells, blood metabolites, and prolactin. At environmental temperatures above 18 C, effects were consistently negative for milk yield and composition, but only above 26 C for feed intake. Prolactin of plasma increased with increasing temperature to 18.2 C and then decreased. No other plasma metabolite or hormone was affected by days pregnant, age, or temperature. Months affected feed intake, milk yield, milk fat percentages, all blood metabolites, and prolactin. Prolactin concentrations increased as daylight hours increased. Our inability to augment established lactation by feeding a supplement of synthetic glucocorticoid to lactating cows is consistent with the view that a lack of avialable corticoids does not limit persistency of lactation in the cow.     

Increasing the concentration of linolenic acid in diets fed to Jersey cows in late lactation does not affect methane production

Although the inclusion of fat has reduced methane production in ruminants, relatively little research has been conducted comparing the effects of source and profile of fatty acids on methane production in lactating dairy cows. A study using 8 multiparous (325 ± 17 DIM; mean ± SD) lactating Jersey cows was conducted to determine effects of feeding canola meal and lard versus extruded byproduct containing flaxseed as a high-C18:3 fat source on methane production and diet digestibility in late-lactation dairy cows. A crossover design with 32-d periods (28-d adaptation and 4-d collections) was used to compare 2 different fat sources. Diets contained approximately 50% forage mixture of corn silage, alfalfa hay, and brome hay; the concentrate mixture changed between diets to include either (1) a conventional diet of corn, soybean meal, and canola meal with lard (control) or (2) a conventional diet of corn and soybean meal with an extruded byproduct containing flaxseed (EXF) as the fat source. Diets were balanced to decrease corn, lard, and canola meal and replace them with soybean mean and EXF to increase the concentration of C18:3 (0.14 vs. 1.20% of DM). Methane production was measured using headbox-style indirect calorimeters. Cattle were restricted to 95% ad libitum feed intake during collections. Milk production (17.4 ± 1.04 kg/d) and dry matter intake (15.4 ± 0.71 kg/d) were similar among treatments. Milk fat (5.88 ± 0.25%) and protein (4.08 ± 0.14%) were not affected by treatment. For methane production, no difference was observed for total production (352.0 vs. 349.8 ± 16.43 L/d for control vs. EXF, respectively). Methane production per unit of dry matter intake was not affected and averaged 23.1 ± 0.57 L/kg. Similarly, methane production per unit of energy-corrected milk was not affected by fat source and averaged 15.5 ± 0.68 L/kg. Heat production was similar, averaging 21.1 ± 1.02 Mcal/d. Digestibility of organic matter, neutral detergent fiber, and crude protein was not affected by diet and averaged 69.9, 53.6, and 73.3%, respectively. Results indicated that increasing C18:3 may not affect methane production or digestibility of the diet in lactating dairy cows.