Concave utility, transaction costs, and risk in measuring discounting of delayed rewards.

Research has consistently found that the decline in the present values of delayed rewards as delay increases is better fit by hyperbolic than by exponential delay-discounting functions. However, concave utility, transaction costs, and risk each could produce hyperbolic-looking data, even when the underlying discounting function is exponential. In Experiments 1 (N=45) and 2 (N=103), participants placed bids indicating their present values of real future monetary rewards in computer-based 2nd-price auctions. Both experiments suggest that utility is not sufficiently concave to account for the superior fit of hyperbolic functions. Experiment 2 provided no evidence that the effects of transaction costs and risk are large enough to account for the superior fit of hyperbolic functions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Irreversibility in the two-body hard-disk lorentz gas

Time-reversible modifications of Newton's equations of motion have been used to simulate irreversible isothermal shear flows. The modified equations have stable solutions for periodic systems with as few as two or three particles. These small-system solutions exhibit thermodynamic irreversibility, entropy production and realistic nonlinear constitutive behavior.     

The relation between methods of coping during adulthood with a history of childhood sexual abuse and current psychological adjustment.

With a community sample of 192 women who had been sexually abused during childhood, the investigators determined if methods of coping in adulthood with the aftermath of child sexual abuse were associated with current symptoms of psychological distress. Multiple regression analyses indicated that disengagement methods of coping with the sexual abuse accounted for unique variance in general psychological distress even after controlling for characteristics of the abuse and methods of coping with other stressors. Disengagement methods of coping were also used more often to deal with the stressful aspects of having been sexually abused than to deal with other stressful events. In contrast, engagement methods of coping were used more often to deal with the other stressors than with sexual abuse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

DNA microarray enhancement using a continuously and discontinuously rotating microchamber

It is demonstrated that the most efficient way to enhance DNA microarray analysis consists of a maximal reduction of the total device volume (to keep the concentration of the available DNA as high as possible), combined with the creation of a strong lateral convective transport of the sample. In the present study, DNA microarray hybridizations are performed in a set of rotating, circular microchambers covering exactly the spotted area of the microarray and with a depth varying between 70 and 1.6 microm. Rotating the microchamber substrate while keeping the microarray stationary, the rotating microchamber bottom wall literally drags the sample past the microarray spots with a velocity which is independent of the fluid layer thickness. Interestingly, it was found that transporting the sample in a discontinuous mode (with stop periods of several minutes) not only yields a more stable and reproducible operation, it also yields significantly larger hybridization intensities (typically a factor of 2-3 larger) than a continuous rotation. This seems to be due to the fact that the velocity field disturbs the binding process at the binding site level. Working under limiting DNA sample mass conditions, the system yielded in a short, 30-min experiment already a 5-fold increase of the hybridization intensity, as compared to a conventional microscope slide/coverslip system operated overnight under diffusion-driven conditions. Compared to a commercial pump-around hybridization system, the gain was even more impressive, precisely due to the fact that the pump-around system requires larger volumes, which with a fixed amount of available genetic material leads to the application of more diluted samples.     

Homosexuality and psychopolitics: An historical overview.

Traces various sources of attitudes toward homosexuality (HMSX) throughout history and explores the scientific and political forces that contributed to the depathologization of HMSX in the psychological community via the American Psychological Association. Advances in the understanding of lesbian and gay issues within psychology since the early 1970s are considered, as well as an analysis of the current state of attitudes toward HMSX within professional psychology. Attitudes toward HMSX within psychology have changed from viewing HMSX as a form of mental illness to considering gay males and lesbians to be an oppressed group in need of special considerations. However, more attention needs to be paid to the diversity within the lesbian and gay male populations in terms of race and ethnicity, religious diversity, class issues, and physical, emotional, and cognitive disability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Training psychologists for hospital practice: A proposal.

Hospital practice has become increasingly important for psychologists over the past decade. However, expanded opportunities for practice require training for competency. The authors propose developing a comprehensive, systematic, and flexible program of training for hospital practice in psychology including graduate course work, supervised practicum experience, and opportunities for retraining. Recommendations for certification in hospital practice, credentialing and privileging, and continuing education are included. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Generalised Asperity-Based Friction Model

Despite considerable research effort, the use of physics-based modelling to predict frictional behaviour is still a debatable question in modern tribological research. This article presents a dry-friction model, based on physical phenomena such as adhesion, elastic–plastic contact and deformation. This contribution offers a means to simulate all kinds of frictional behaviour that is observed in experimental research. The contact of two bodies through their surfaces is transformed into the contact of a body that is provided with asperities and containing material and geometrical information of both of the mating surfaces, and a counter profile, holding solely geometrical information. The local adhesion between the asperity tips and the counter profile, together with the elastic–plastic behaviour of the asperities themselves, form the basis for this model. The simulation results show qualitatively good agreement with experimental study. Friction and contact phenomena such as normal creep, increasing static coefficient of friction with increasing dwell time, pre-sliding hysteresis with nonlocal memory, Stribeck and viscous effect, frictional lag, stick–slip and dynamical oscillations are revealed by this model. Furthermore, future improvement and refinement of the model is possible (and ongoing) so as to incorporate lubrication and asperity wear.     

电源转换应用中数字反馈回路的益处

市场因素正在推动智能电源的发展,包括电源的外部控制和生产中的软件配置。实现上述目标的方法之一就是在电源转换回路中采用数字反馈控制。电源设计人员已经在智能电源中采用了单片机（MCU）来实现通信、监视、控制和诸如上电时序、软启动和拓扑控制等确定性功能。但是,就在不久前,由于没有合适的兼具成本效率的技术,对电源转换回路进行完全的数字控制仍不可能。