Impairment in category fluency in ischemic vascular dementia.

The underlying mechanisms for impaired output on letter (F, A, and S) and category (e.g., animal) word list generation (WLG) tasks in subcortical ischemic vascular dementia (IVD) were investigated. Normal control (NC) and Alzheimer's disease (AD) participants were also studied. IVD and NC participants performed better on category than letter WLG tasks, whereas the opposite was observed among AD participants. IVD participants produced fewer responses than AD participants on letter WLG tasks, but there was no difference between AD and IVD participants on the "animal" WLG task. AD participants scored lower than IVD and NC participants on animal WLG indexes measuring semantic knowledge. There were few differences between IVD and NC participants. The reduced output on the animal WLG task for IVD participants is consistent with search-retrieval deficits. The reduced output of AD participants may be caused by degraded semantic knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Magnetic resonance imaging correlates of attention-deficit/hyperactivity disorder in children.

This study compared magnetic resonance imaging size differences in several brain regions and neurocognitive function in a group of male and female children with attention-deficit/hyperactivity disorder (ADHD) with no comorbid learning disorders with a normal control group of children. The ADHD group demonstrated smaller total brain, superior prefrontal, and right superior prefrontal volumes, as well as significantly smaller areas for cerebellar lobules I-V and VIII-X, total corpus callosum area, and splenium. No group differences were observed for the inferior prefrontal, caudate, or cerebellar volumes, or for the area of cerebellar lobules VI-VII. In the ADHD group but not in the control group, greater right superior prefrontal volume predicted poorer performance on a test of sustained attention. Patterns of brain abnormality did not differ in male and female children with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Biocompatible Arginine‐Based Polycation

Self assembly between cations and anions is ubiquitous throughout nature. Important biological structures such as chromatin often use poly­valent assembly between a polycation and a polyanion. The biomedical importance of synthetic polycations arises from their affinity to polyanions such as nucleic acid and heparan sulfate. However, the limited biocompatibility of synthetic polycations hampers the realization of their immense potential. By examining biocompatible cationic peptides, we hypothesize that a biocompatible polycation should be biodegradable and made from endogenous cations. We design an arginine‐based biodegradable polycation and demonstrate that it is more compatible by several orders of magnitude than conventional polycations in vitro and in vivo. This biocompatibility diminishes when L ‐arginine is substituted with D ‐arginine or when the biodegradable ester linker is changed to a biostable ether linker. We believe that this design can lead to many biocompatible polycations that can significantly advance a wide range of applications including controlled release, tissue engineering, biosensing, and medical devices.     

Observations in the statistical analysis of NBG-18 nuclear graphite strength tests

The purpose of this paper is to report on the selection of a statistical distribution chosen to represent the experimental material strength of NBG-18 nuclear graphite. Three large sets of samples were tested during the material characterisation of the Pebble Bed Modular Reactor and Core Structure Ceramics materials. These sets of samples are tensile strength, flexural strength and compressive strength (CS) measurements. A relevant statistical fit is determined and the goodness of fit is also evaluated for each data set. The data sets are also normalised for ease of comparison, and combined into one representative data set. The validity of this approach is demonstrated. A second failure mode distribution is found on the CS test data. Identifying this failure mode supports the similar observations made in the past. The success of fitting the Weibull distribution through the normalised data sets allows us to improve the basis for the estimates of the variability. This could also imply that the variability on the graphite strength for the different strength measures is based on the same flaw distribution and thus a property of the material.     

Dialogue as the interplay of otherness and shared humanity.

Presents a reply by B. Fowers and B. Davidov to Islam's comments (see record 2007-14606-019) regarding their article (see record 2006-11202-002). Islam noted that virtues are often presented as universally valid character strengths, yet formulations of virtues are always embedded in a particular cultural context, a point we took pains to make in our article. We focus our response on Islam's important suggestion that this tension between universal human characteristics and the particulars of cultural context is indissoluble. Whereas he suggested this tension leads to contradiction and paradox, we see it as a fertile dialectic. The virtue of openness to the other is also subject to the same tension of abstract formulation and particular application. Although we formulated this virtue in a very general way, any instantiation of it would be shaped by the particulars of the cultural context and the situation in which it is exercised. We introduced the concept of dialogue because it is constituted not only by differences between individuals or groups but even more fundamentally by the dialectical relationship between those differences in cultural particularities and the universal human capacities for reason, curiosity, and social engagement, among others. Dialogue acknowledges the indissoluble otherness one finds in those culturally different from oneself, and yet real interchange can only occur because participants in dialogue exercise the cognitive flexibility characteristic of human beings and recognize a shared humanity with the other. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Innovations in Large-Scale Supported Distance Teaching: Transformation for the Internet,Not Just Translation

This paper reports on large-scale trials of Internet-based university-level distance teaching. The use of technology, and more specifically the Internet, has been an important advance for distance education. However, simply translating material from familiar media into electronic form is rarely productive—and is certainly inadequate for supported distance education, which aims to engage the student in a “community of learning.” The value Internet technology brings to distance education lies not in direct translation from other media but in transformation of support mechanisms to exploit its potential range. The paper addresses how instruction and support functions can be served and potentially enhanced by an Internet-based structure. It considers which changes in culture help to preserve or improve teaching quality while adapting to screen-based and often asynchronous interactions. It discusses our trials of mechanisms for interactions among students and tutors; assignment marking using an electronic marking tool; electronic assignment handling; synchronous and asynchronous Internet-based problem sessions; and automatic student registration. The paper summarizes qualitative and quantitative findings of an extensive evaluation involving several hundred students over three courses and considering learning, student experience, assignment marking, problem sessions, scalability, and integration into existing administrative structures. It highlights both costs and gains of using the Internet to transform the distance learning environment for those associated with it: students, tutors, administrators, and institutions.     

Computational implementation of a systems prioritization methodology for the Waste Isolation Pilot Plant: a preliminary example

A systems prioritization methodology (SPM) is under development for the Waste Isolation Pilot Plant (WIPP). The SPM is based on a large numerical integration problem that must be repeatedly evaluated to determine compliance probabilities associated with different experimental programs and design modifications. Due to the complexity and computational cost of the underlying integration problem, the implementation of the SPM must be planned very carefully. This presentation describes a preliminary application of the SPM, designated SPM-l, performed to provide insights to facilitate the development and implementation of the methodology. Topics illustrated by SPM-1 include definition of probability spaces on which the SPM is based, use of Latin hypercube sampling and simple random sampling to integrate over different probability spaces, selection of mechanistic calculations to be performed, efficient use of the limited number of mechanistic calculations that can be performed, and assembly of many individual calculations into a complete analysis.     

Psychology as public philosophy: An illustration of the moral dimension of psychology with marital research.

Suggests that contemporary marriage is at the heart of a serious cultural paradox that renders it strongly valued, but rather brittle. Scientific and therapeutic approaches to this dilemma have had limited success in resolving this problem because professionals have accepted and promoted the popular aspiration of personal fulfillment through marriage, which may have engendered the fragility of marriage. The author provides a brief hermeneutic account designed to make the incoherence of contemporary marriage more intelligible, and to clarify the moral dimension of psychology. Marital research illustrates how a hermeneutic perspective can guide a specific research domain in becoming more responsive to the essential social and ethical concerns that animate it. Suggestions for how researchers can explore why marriage is so central to modern life are offered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Derivation of efficiency and loss factors for solar air heaters

The collector efficiency factor which measures the effectiveness of a collector absorber plate in transferring heat to the transport fluid, and the loss factor for air-type collectors, are mathematically derived. These equations provide a method for computing these two factors, which with the effective transmittance-absorptance product, enables one to write the generalized performance equation. The prediction of performance provided by this procedure is particularly useful in comparing performance of different collectors and for studying a specific collector's performance with changes in environment and design parameters which can be controlled to some extent by the designer.