Second-order parallel processing: Visual search for the odd item in a subset.

Visual search tasks in which participants searched for an odd element in a subset of items were investigated. Participants searched for an item of odd orientation in the red subset. The target was a red line of X°, distractors were green lines of X° and red lines of Y°. The orientations, X and Y, changed on every trial. In this task, orientation information was useful only after color had been used to select the relevant subset. Results show that response time (RT) and error data were different from standard color X orientation conjunction searches (Experiment 1). RT?×?Set Size functions had slopes near 0 ms per item (Experiment 2). The selection of the subset appeared to take 200-300 ms (Experiments 2 and 3). Subset selection was based on properties of the relevant subset, not the irrelevant subset (Experiment 4). It was more difficult (perhaps impossible) to select a subset defined by 2 colors (Experiment 5). Random variation in an irrelevant dimension did not disrupt subset search (Experiment 6). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Clinical and treatment correlates of access to Section 8 certificates for homeless mentally ill persons

OBJECTIVE: The study assessed how clients' housing preference and other variables were related to the acquisition of Section 8 certificates, facilitating independent living, for homeless persons with severe mental illness who were being served by an experimental assertive community treatment team. METHODS: For 77 clients, demographic and clinical differences between receivers and nonreceivers of certificates were examined, and correlates of time from referral to the team to completion of the Section 8 application were analyzed. Reasons clients did not receive certificates and housing outcomes were summarized in relation to client preference. RESULTS: The 34 clients who received certificates (44 percent) had significantly less psychopathology after three months than did nonreceivers and tended to have affective disorders rather than schizophrenia. Of the 43 nonreceivers, the two largest groups were 19 clients who did not want certificates and ten clients who wanted certificates but whom staff considered unable to live safely in an unsupervised apartment. The mean +/- SD length of time for application for a certificate was 5.7 +/- 5.8 months. Longer time to apply was significantly associated with having schizophrenia, having the team as a representative payee, and showing increased psychotic symptoms at referral and at three months. CONCLUSIONS: The study suggests that it is possible to honor the housing preferences of the majority of homeless persons with severe mental illness if adequate resources are provided. However, staff may view persons who have schizophrenia and more symptoms as needing more supervision than those clients prefer. Homeless mentally ill persons may also take longer than more symptomatic persons to pursue independent living through a Section 8 certificate.     

Off-diagonal Mueller matrix elements in backscattering from highly diffusive media.

Measurements of a reduced Mueller matrix in backscattering from highly diffusive, dielectric samples are reported as a function of the angle of incidence. It was found that the off-diagonal terms depend greatly on the angle of incidence, increasing to a maximum near grazing incidence. We show that, despite a significant scattering originating in the bulk of such diffusive media, the nontrivial behavior of the off-diagonal Muller matrix is primarily due to surface scattering phenomena. The experimental data can be simply explained by assuming a random orientation of small particles and considering only double scattering in the plane of the surface.     

An ion-channel-containing model membrane: structural determination by magnetic contrast neutron reflectometry

To many biophysical characterisation techniques, biological membranes appear as two-dimensional structures with details of their third dimension hidden within a 5 nm profile. Probing this structure requires methods able to discriminate multiple layers a few ?ngstr?ms thick. Given sufficient resolution, neutron methods can provide the required discrimination between different biochemical components, especially when selective deuteration is employed. We have used state-of-the-art neutron reflection methods, with resolution enhancement via magnetic contrast variation to study an oriented model membrane system. The model is based on the Escherichia coli outer membrane protein OmpF fixed to a gold surface via an engineered cysteine residue. Below the gold is buried a magnetic metal layer which, in a magnetic field, displays different scattering strengths to spin-up and spin-down neutrons. This provides two independent datasets from a single biological sample. Simultaneous fitting of the two datasets significantly refines the resulting model. A β-mercaptoethanol (βME) passivating surface, applied to the gold to prevent protein denaturation, is resolved for the first time as an 8.2 ± 0.6 ? thick layer, demonstrating the improved resolution and confirming that this layer remains after OmpF assembly. The thiolipid monolayer (35.3 ± 0.5 ?), assembled around the OmpF is determined and finally a fluid DMPC layer is added (total lipid thickness 58.7 ± 0.9 ?). The dimensions of trimeric OmpF in isolation (53.6 ± 2.5 ?), after assembly of lipid monolayer (57.5 ± 0.9 ?) and lipid bilayer (58.7 ± 0.9 ?), are precisely determined and show little variation.     

The shock response,simulation and microstructural determination of a model composite material

The capability to assess microstructural details in a polymer matrix composite is important in addressing composite design for engineering applications. The generation of three-dimensional microstructure using a non-invasive high-resolution experimental diagnostics method will advance our knowledge within this field. An inert composite has been studied, and both X-ray microtomography (XRT) for microstructural investigation in 3D and a parallel series of shock experiments (with associated modelling) have been conducted. The experimental aims of this study lay in several areas: firstly, to adequately define the bulk morphology; secondly, to determine the geometry of defects within the material; and finally, to demonstrate a direct linkage with the mechanical response determined by finite element analysis. This work is the first step in finding a way to non-invasively link 3D microstructural invesigation and numerical simulation to predict the shock performance of a composite material.     

Breaches in the therapeutic alliance: An arena for negotiating authentic relatedness.

Argues that the clarification of the processes involved in working through breaches or ruptures in the therapeutic alliance, is a vitally important task for psychotherapy theorists and researchers. It is suggested that these inevitable problems in the therapeutic alliance provide important opportunities for clarifying factors that may create barriers to authentic relatedness in clients' everyday lives. Working through these problems can provide clients with valuable experience in the important tasks of reconciling the needs for relatedness and agency and of coming to accept both self and other. The current paradigm shift in psychotherapy theory and practice toward more relational and constructivist perspectives, however, has established a particularly ripe climate for enhancing the understanding of the client–therapist relationship through a differentiated exploration of these concerns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceiving scene layout through an aperture during visually simulated self-motion.

Tested scene perception during depicted self-movement. In Exp 1, viewers reproduced angular scene configurations, revealed over time by camera motions in depth. Viewers used visible flow to update off-screen locations of landmarks that had been drawn from view and thereby perceived scenes in depth beyond the display's boundaries. Exps 2 and 3 tested whether offscreen space is perceived as a function of depicted velocity and time and whether information from prior views is used. Viewers predicted when lateral movement would reveal a peripheral landmark whose location was shown in a prior panoramic view. Accurate responses, observed under certain conditions, would result if viewers perceived space according to S?=?∫ V dt (D. Algom and L. Cohen-Raz, 1984, 1987; R. Jagacinski et al, 1983). When required to picture wide spans in space yet to emerge, however, viewers responded as if these spans were compressed. The theoretical implications of the ability to retrieve, transform, and apply information after a discontinuous transition from a prior view are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rotor Synchronized MAS Two-Dimensional Exchange NMR in Solids. Principles and Applications

The principles of the rotor synchronized magic angle spinning (MAS) two-dimensional exchange NMR, first proposed by Veeman and coworkers are reviewed, with particular emphasis on situations where chemical exchange in solids proceeds in concert with molecular reorientation. Calculations of cross peak intensities as function of the ratio between the chemical shift anisotropy and the spinning rate are presented for several cases. These calculations emphasize the advantage of using slow spinning rates (ω_R < ω_LΔσ) in such experiments when detailed information about mechanistic pathways in solids is sought. Three applications of the method to solid systems using carbon-13 NMR are described. These include: (a) Trimethylsulfoxonium iodide, in which the molecules undergo 120°-jumps about the molecular C₃ symmetry axis; (b) Tropolone, where the tautomeric hydrogen shift is found to be a consequence of the self diffusion within the crystal lattice, and in general accompanied by molecular reorientation. Here the two-dimensional pattern is used to obtain information about the various mechanisms of the diffusion process; (c) Bullvalene, where a quantitative analysis of the cross peak intensities as function of the mixing time provides kinetic information on two independent processes, viz. symmetric threefold jumps and a concerted Cope rearrangement-molecular reorientation reaction.     

中国南水北调项目的可行性探讨

中国的南水北调工程，如果全部实施，每年可从长江流域调水400～500亿m^3到华北平原，以缓解华北地区的3～3．25亿人的水短缺问题。南水北调工程第一阶段(调水200亿m^3／年)建设，已于2002年或2003年开工(已在2002年12月开工。校译者注)，需投入170亿美元建设资金(包括70亿美元的附属项目资金)。世界银行最近研究认为“该项目在经济上有较大效益”。但世界自然基金会却反对该结论，争议较大。笔者认为该项目在经济上投资昂贵，并需要移民30万人，调水价格也很难为农业所承担；但是，中国在社会经济发展方面正发生着史无前例的变化，而华北平原严重水短缺已引发了一系列严重的问题。通过将当地灌溉用水重新配置并转让给生活和工业用户以及改善环境用水，实际操作是不可能的。而南水北调工程的实施可在很大程度上缓解这些矛盾，从这个意义(更多的是从政治上和实际需要出发)说，而不是严格从经济上或粮食安全的角度考虑，中国政府决策实施此项目是完全可以理解的。