Resolution of conflict between goal-directed actions: Outcome encoding and neural control processes.

According to O-R theory of instrumental learning, incongruent biconditional discriminations should be impossible to solve in a goal-directed manner because the event acting as the outcome of one response also acts as a discriminative stimulus for an opposite response. Each event should therefore be associated with two competing responses. However, Dickinson and de Wit (2003) have presented evidence that rats can learn incongruent discriminations. The present study investigated whether rats were able to engage additional processes to solve incongruent discriminations in a goal-directed manner. Experiment 1 provides evidence that rats resolve the response conflict that arises in the incongruent discrimination by differentially encoding events in their roles as discriminative stimulus and as outcome. Furthermore, Experiment 2 shows that once goal-directed control has been established the dorsomedial prefrontal cortex is not directly involved in its maintenance but rather plays a central role in conflict resolution processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Power of Tests for Non-Linearity: The Escribano–Pfann Model

The power of the recently proposed Escribano–Pfann (1998) model ofasymmetryis examined via Monte Carlo simulation. As found previously for analternative asymmetric model, the power of this model is seen to be low.     

Exploratory investigation of the chemical characteristics and relative toxicity of ambient air particulates from two New Zealand cities

We examined the chemical composition and biological response associated with particulate emissions from the two largest cities in New Zealand, Auckland and Christchurch. The organic and water-soluble fractions were isolated from the particulate matter (PM). The organic fraction was examined for PAH content, direct mutagenicity, CYP1A1 induction, and cytotoxicity and TNF-α release in RAW264.7 macrophages. The water-soluble fraction was examined for metal content, and cytotoxicity and TNF-α release in RAW264.7 macrophages.Particulate, PAH and water-soluble metal concentrations were all higher in PM collected from Christchurch, being highest in May-July when woodburners for home heating are widely in use. In contrast, PM from Auckland showed the highest concentrations in March, but PAH and metal concentrations were highest in July. We found marked differences in the biological response elicited by ambient air PM: the organic extracts of Christchurch PM_2.5 and PM₁₀ showed higher mutagenicity and CYP1A1 induction compared with PM₁₀ from Auckland. In contrast, water-soluble extracts of Auckland PM were more cytotoxic and resulted in greater TNF-α release than those from Christchurch PM, although they had a lower metal content. The organic fraction of PM from both cities did not induce any cytokine release, and the organic extract from Auckland samples showed no cytotoxicity; smaller PM mass was available for testing for these samples. Biological responses typically occurred at lower doses of the organic extract, indicating that organic components may be more important in eliciting effects than water-soluble components.Preliminary apportionment of the biological responses to the dominant sources of PM in both cities-woodburners and vehicles-was undertaken. This indicated that for both cities, vehicles have a greater contribution to the direct mutagenic activity of ambient PM than woodsmoke, despite a lower contribution to ambient PM. In contrast, woodsmoke is estimated to have a greater contribution to CYP1A1 induction of ambient PM. The calculated activity forms only a small proportion of the activity observed in extracts of ambient PM from Christchurch, particularly for mutagenicity, and may indicate a significant influence of atmospheric transformation processes on biological response. Only data for mutagenicity and CYP1A1 activity could be used for apportionment as low and/or variable cytotoxicity or TNF-α release response were obtained for either the individual source or ambient PM at the doses tested. Further, in the case of the water-soluble extracts from Auckland, additional components are suggested to have a role in the observed activity.     

Effects of Plant Identity and Chemical Constituents on the Efficacy of a Baculovirus Against Heliothis virescens

Baculoviruses are arthropod-specific, dsDNA viruses primarily used to control lepidopteran pests. A limitation of the use of baculoviruses for pest control is that their efficacy is modifiable by host-plant chemicals. The levels of phenolic substrates and two foliar oxidative enzymes, peroxidase (POD) and polyphenol oxidase (PTO), were significant predictors of disease caused by a baculovirus in Heliothis virescens fed on either cotton or lettuce; POD was the more influential of the two enzymes. The higher the plant phenolase activity, the lower the percent mortality and the slower the insects died from viral infection. Whether a particular class of phenolic substrates was correlated with enhanced or attenuated baculoviral disease depended upon context, i.e., admixture. Diminution of viral efficacy by plant oxidative activity may compromise the compatibility of baculoviruses with other components of an integrated pest management system such as host plant resistance.     

Fluorescence excitation spectroscopy of polystyrene near the critical concentration c*

The critical concentration c* was measured using both fluorescence excitation spectroscopy and light scattering for four narrow molecular weight distribution samples of polystyrene (MW = 225,000–1,500,000) in bicyclo[4.4.0]decane (decahydronaphthalene, decalin) at 20 and 30°C. A discontinuity in the corrected intensity of a band in the excitation spectrum (assigned to the dimmer complex) as a function of concentration allowed determination of the critical concentration, c*, from the excitation spectra. The c* resulting from fluorescence and light scattering were identical within experimental error and were comparable to c* values calculated from literature methods. Fluorescence excitation spectroscopy should be a convenient method for determining c* for aromatic polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 360–364, 2007     

Opt-out testing for stigmatized diseases: A social psychological approach to understanding the potential effect of recommendations for routine HIV testing.

Objective: Little research has studied experimentally whether an opt-out policy will increase testing rates or whether this strategy is especially effective in the case of stigmatized diseases such as HIV. Design and Main Outcome Measures: In Study 1, a 2 × 2 factorial design asked participants to make moral judgments about a person’s decision to test for stigmatized diseases under an opt-in versus an opt-out policy. In Study 2, a 2 × 2 factorial design measuring testing rates explored whether opt-out methods reduce stigma and increase testing for stigmatized diseases. Results: Study 1 results suggest that getting tested draws suspicion regarding moral conduct in an opt-in system, whereas not getting tested draws suspicion in an opt-out system. Study 2 results suggest that an opt-out policy may increase testing rates for stigmatized diseases and lessen the effects of stigma in people’s reluctance to test. Discussion: A social psychological approach to health services can be used to show how testing policies can influence both the stigmatization associated with testing and participation rates. An understanding of how testing policies may affect patient decision making and behavior is imperative for creating effective testing policies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Why Germany？

在这里，每一个橱窗，小窗台，都充满着精心打理的痕迹 窗台里的鲜花、小玩偶都展现德国人的精致与爱生活……     

Spatially resolved hydrogen desorption from aluminum hydride observed by magnetic resonance imaging

Light metal hydrides represent a promising class of materials for hydrogen storage. However, there are several technical challenges to overcome before their potential can be realized. Key among these is the often adverse absorption and desorption kinetics, which are a function of intrinsic reaction rates and practical operating temperatures. Modifying and controlling these kinetics require a thorough understanding of the hydrogen absorption and desorption processes. In this study, we have investigated the thermal decomposition of aluminum hydride, AlH₃, with Magnetic Resonance Imaging in order to visualize spatially the progress and extent of the reaction.