Age of drinking onset, driving after drinking, and involvement in alcohol related motor-vehicle crashes.

This study assessed whether persons who begin drinking at younger ages are more likely to report drunk driving and alcohol-related crash involvement over the life course, even after controlling analytically for diagnosis of alcohol dependence, years of drinking alcohol, and other personal characteristics associated with the age respondents started drinking. A national survey asked 42,862 respondents the age that they started drinking, whether they drove after drinking too much, and whether they were in motor-vehicle crashes because of their drinking. This analysis focused on 27,081 (65%), who reported ever drinking in their lifetime. The earlier the age respondents started drinking, the more likely they were to report driving after drinking too much and being in a motor-vehicle crash because of their drinking even after adjusting for current/ever diagnosis of alcohol dependence, number of years respondents had been drinking, and other characteristics and behaviors associated with the age respondents started drinking. Particularly, among persons who were never alcohol-dependent, those who began drinking in each age group under 21, relative to those starting at age 21 or older, were more likely to report "ever" and "in the past year" being in a crash after drinking too much. The traffic safety benefits of delaying drinking may extend well beyond the legal drinking age of 21.     

Novel Planar Electromagnetic Bandgap Structures for Mitigation of Switching Noise and EMI Reduction in High-Speed Circuits

Planar electromagnetic bandgap (EBG) structures with novel meandered lines and super cell configuration are proposed for mitigating simultaneous switching noise propagation in high-speed printed circuit boards. An ultrawide bandgap extending from 250 MHz to 12 GHz and beyond is demonstrated by both simulation and measurement, and a good agreement is observed. These perforated EBG-based power planes may cause spurious and unwanted radiation. In this paper, leakage radiation through these imperfect planes is carefully investigated. It is found that the leakage field from these planar EBG structures is highly concentrated around the feed point, and the field intensity is attenuated dramatically when passing across several periods of patches. A novel concept of using these EBG structures for electromagnetic interference reduction is also introduced. Finally, the impact of power plane with EBG-patterned structures on signal integrity is studied.     

A depressed collector system for a quasi-optical gyrotron with precisely controlled magnetic flux lines

Design of a depressed collector system for a quasi-optical gyrotron, which had a severe constraint on the maximum allowable radius of the collector region is outlined. The needs for unwinding of spent beam and for energy sorting could be accommodated by precise control of the magnetic field profile, especially in the collector region. Techniques used for defining and obtaining such profiles; and for dovetailing the profile with the collector geometry are discussed. Results on profiles and electron trajectories are presented, which demonstrate the feasibility of the design. From primary electron trajectories a collector efficiency of up to 68% has been calculated for a three collector design.     

Effect of depression level and length of acquaintance on reaction of others to a request for help.

Examined an interpersonal-process view of depression by assessing 60 undergraduates' reactions to a request for help from a hypothetical depressed or nondepressed person with whom they had been acquainted for a relatively short (2 wks) or long (1 yr) period of time. Ss responded to each of the 4 hypothetical persons by indicating their probable affective reactions to the request, the number of minutes they would be willing to help, their desire for future social contact with the hypothetical person, and their expectations of future requests for help. Results indicate that Ss felt significantly more concern and were willing to provide significantly more time for long-term acquaintances. Requests from depressed persons elicited significantly more anger and social rejection but equal amounts of concern and willingness to help. This mixed response pattern was interpreted as providing partial support for an interpersonal-process view of depression. A path analysis provided limited support for J. C. Coyne's (see record 1979-01146-001) hypothesis that rejection of depressed persons results from the negative mood they induce in others. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The electron cyclotron maser as a high-power traveling wave amplifier of millimeter waves

The electron cyclotron maser instability has been exploited as the basis for a new type of traveling wave amplifier which operates at unusually high-power levels at millimeter wavelengths. The first experimental model of this amplifier has been operated at 35 GHz and has demonstrated a stable gain of 17 dB and an output power of 10 kW (unsaturated). The gain was linear over a dynamic range > 30 dB. The absolute value of the gain and its dependence on current and magnetic field were in excellent agreement with theoretical calculations. Bandwidth and saturated power have yet to be measured directly, but no fundamental problems were observed which will prevent successful achievement of the design predictions (viz., bandwidth ≃ 10 percent, power on the order of 10⁵W, efficiency > 10 percent).     

Performance of a wideband, three-stage, mixed geometry gyrotwystronamplifier

A three-stage, mixed geometry gyrotwystron amplifier has recently been operated and characterized at 4.5 GHz. Gyrotwystrons are hybrids of the gyroklystron and gyro-traveling-wave tube (gyro-TWT) amplifiers. In the device which was studied, the first two stages were tunable rectangular resonator cavities, and the third (output) stage was a circular cylindrical waveguide traveling wave section. All three stages operate in fundamental mode, and are separated by cut-off drift regions. This experiment was conceived as an extension of a previous three-cavity gyroklystron experiment, the motivation being to improve upon the gyroklystron instantaneous bandwidth of 0.4% while not sacrificing efficiency or gain. Measurements of gyrotwystron performance showed a 1.5% instantaneous bandwidth, a fourfold increase over that of the gyroklystron. The gain-bandwidth product of the gyrotwystron exceeded that of the gyroklystron by a factor of 6     

Harmonic gain and noise in a frequency-doubling gyro-amplifier

Nonlinear gain in a 34-GHz three-stage frequency-doubling gyro-traveling wave tube (gyro-TWT) has been experimentally studied. The device consists of a thermionic electron gun, TE/sub 01//spl rarr/TE/sub 02/ fundamental gyro-TWT input section, second harmonic TE/sub 03/ intermediate buncher section, and a second harmonic TE/sub 02//spl rarr/TE/sub 04/ complex output circuit. Nonlinear bunching in the electron orbital phase generates harmonics of the input signal in the beam current, which excite the subsequent circuits at the second harmonic frequency. Since the gain is nonlinear, noise or applied sideband signals intermodulate with the carrier generating high-order products in the output. Therefore, it has been suggested that the noise figure of these devices may be unreasonably high. In this study, the complex harmonic transfer characteristics were experimentally measured and compared with calculations based on the assumption that the gyro-amplifier gain can be described, in the narrowband sense, as a classical frequency-doubling circuit. The results show that narrowband intermodulation gain is 6 dB higher than the carrier as predicted in the small signal limit, but as the device reaches saturation the nonlinear products become suppressed with respect to the carrier. Tests on the broadband gain characteristics show that output noise consists of second harmonic shot noise spontaneously excited in the output circuits along with the products of the intermodulation between external noise and the carrier. Good agreement between the experimental results and the calculations is demonstrated.     

Clients' perceptions and evaluations of similarities to and differences from their counselors.

Forty-seven community mental health clients were asked in an open-ended format to describe the ways in which they were similar to and different from their counselors; rate how significantly these similarities and differences affected the counseling relationship; and categorize the type of effect on the counseling relationship as being either good, bad, or neutral. Results revealed that personality traits were most frequently cited as similarities. Demographic variables and personality traits were most frequently cited as differences. Both similarities and differences were rated as having primarily positive effects on the counseling relationship, with similarities having a stronger perceived impact on the relationship than differences. Methodological considerations for exploring personality-trait and demographic similarities and differences between counselors and clients are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)