An exercise design approach to understanding assessment center dimension and exercise constructs.

Arobust finding in assessment center research is that ratings cluster according to exercises and not dimensions. Seeking further understanding of exercise effects, the authors proposed 2 exercise-based factors (exercise form and exercise content) as sources of variance in assessment center ratings. Exercise designs were manipulated so that 2 levels of form (leaderless group discussions and role-play exercises) were crossed with 2 levels of content (cooperative and competitive task designs). Analysis of variance (ANOVA) and confirmatory factor analysis procedures applied to multitrait–multimethod ratings of 89 high school student assessees revealed that most of the variance in the ratings was explained by exercises and not dimensions. Exercise form accounted for 16% of method variance, whereas exercise content had near zero effect. The form effect was primarily due to higher correlations of dimension ratings across role-play exercises. Practical implications and future directions for exercise design research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Management of nasopharyngeal and oropharyngeal stenosis in children

Nasopharyngeal stenosis and oropharyngeal stenosis are rare and challenging problems in the pediatric population. The most common etiology is currently the surgical trauma associated with adenotonsillectomy. Stenosis can vary from a thin band to a complete obstructing cicatrix. Presenting symptoms range from mild hyponasal speech to severe airway obstruction. We present a series of eight children with varying degrees of stenosis and associated symptoms. Choice of treatment varied with the severity of disease. In our series, successful interventions included triamcinolone acetonide injection, lysis of adhesions, rotational and advancement mucosal flaps, and jejunal free flap. Preoperative evaluation and individualized surgical repair are essential for successful treatment.     

Treatment with alendronate prevents fractures in women at highest risk: results from the Fracture Intervention Trial

BACKGROUND: The efficacy of antiresorptive therapy in preventing fractures in women at highest fracture risk, such as very elderly women or those with severe osteoporosis, is uncertain. PARTICIPANTS AND METHODS: Using data from a double-blind, randomized, placebo-controlled clinical trial that enrolled 2027 postmenopausal women aged 55 to 81 years with low femoral neck bone mineral density (BMD) and existing vertebral fractures, we examined the consistency of the effect of treatment with alendronate sodium in preventing fractures within a priori-specified risk subgroups defined at baseline by age, bone density, number of preexisting vertebral fractures, and history of postmenopausal fracture. The women were randomized to oral administration of alendronate or placebo and followed up for an average of 2.9 years. The initial dose of alendronate sodium was 5 mg/d; the dosage was increased from 5 to 10 mg/d at 24 months. New vertebral fractures, the primary end point of this arm of the trial, were defined by morphometry as a decrease of 20% and at least 4 mm in any vertebral height between baseline and a follow-up radiograph at 36 months. Incident clinical fractures, the secondary end point, included nonspine and clinical (symptomatic) vertebral fractures. All clinical fractures were confirmed with x-ray film reports or, in the case of clinical vertebral fractures, x-ray films. RESULTS: Overall, there was a 47% significant reduction in risk of new vertebral fractures in the alendronate group compared with the placebo group. The reduction in risk of new vertebral fracture was consistent across fracture risk categories including age (relative risk [RR], 0.49 in women < 75 years compared with 0.62 in those > or = 75 years), BMD (RR, 0.54 in women with a femoral neck BMD < 0.59 g/cm2 [median] compared with 0.53 in those with a BMD > or = 0.59 g/cm2), and number of preexisting vertebral fractures (RR, 0.58 in women with 1 vertebral fracture compared with 0.52 in those with > or = 2). The overall significant 28% reduction in risk of incident clinical fractures in the alendronate group compared with the placebo group was also observed within these subgroups. Compared with the number of lower-risk women, a similar or smaller number of high-risk women needed to be treated to prevent 1 fracture. For example, 8 women aged 75 years or older compared with 9 women younger than 75 years, or 4 women with 2 or more existing vertebral fractures compared with 16 women with 1 existing vertebral fracture, needed to be treated with alendronate for 5 years to prevent 1 new vertebral fracture. CONCLUSIONS: Alendronate effectively reduces fracture risk in postmenopausal women with vertebral fractures and low BMD, including those women at highest risk because of advanced age or severe osteoporosis. Since the risk reductions observed with alendronate treatment were consistent within fracture risk categories, more fractures were prevented by treating women at highest risk.     

Structure and Ordination of Epiphytic Invertebrate Communities of Four Coastal Wetlands in Green Bay,Lake Michigan

Epiphytic macroinvertebrate communities of four coastal wetlands of Green Bay, Lake Michigan were compared by taxonomic composition, feeding group composition, and environmental influences using Bray-Curtis ordination. Ordination scores from the most sheltered oligotrophic site, Portage Marsh, were distinct from the eutrophic, exposed sites located in middle and lower Green Bay— Seagull Bar, Little Tail Point, and Dead Horse Bay. Epiphyton chlorophyll a, phytoplankton chlorophyll a, and specific conductance strongly correlated to the ordination axes, indicating the trophic gradient within Green Bay was a primary environmental influence. The feeding group compositions at the sites were consistent with the type and abundance of food available. Portage Marsh is a scraper-shredder system, with macroinvertebrates feeding mainly on epiphyton and coarse particulate detritus. Dead Horse Bay and Little Tail Point are collector systems, sustained by phytoplankton and fine particulate organic matter. Seagull Bar is intermediate in trophic position along the ordination axes, but more closely resemble the latter two sites. The type and abundance of food resources available to these invertebrate communities are influenced by wave exposure, light attenuation, nutrient levels, and algae levels of the littoral and pelagial waters. Macroinvertebrate communities were sensitive to shifts in food resources, which generated shifts in trophic structure.     

Varieties of working memory as seen in biology and in connectionist/control architectures

Biological and computational concepts that underlie the nature of working memory are briefly reviewed. The conceptualization of working memory has changed dramatically in the last 30 years. Current biological work has monitored several aspects of memory, including activation decay, sustained activation, long-term connection change, and differential structures for episodic (hippocampal formation) and procedural learning. Current connectionist modeling has identified factors including multiple-region-based processing, control processing as well as data storage, tradeoffs between fast- and slow-connection-change learning effects, and the speeding of acquisition via multiple levels of learning. The need to relate the biological, behavioral, and computational constraints into models of working memory is discussed. Finally, conceptualizations of working memory must acknowledge the need for human learning systems to be robust enough to operate in a dynamic world.     

7.5 Gb/s monolithically integrated clock recovery circuit using PLLand 0.3-μm gate length quantum well HEMT's

A monolithically integrated clock recovery (CR) circuit making use of the phase-locked loop (PLL) circuit technique and enhancement/depletion AlGaAs/GaAs quantum well-high electron mobility transistors (QW-HEMT's) with gate lengths of 0.3 μm has been realized. A novel preprocessing circuit was used. In the PLL a fully-balanced varactorless VCO was applied. The VCO has a center oscillating frequency of about 7.7 GHz and a tuning range greater than 500 MHz. A satisfactory clock signal has been obtained at a bit rate of about 7.5 Gb/s. The power consumption is less than 200 mW at a supply voltage of -5 V     

Integrity tests: Facts and unresolved issues.

Describes 2 independent reports, recently completed by the American Psychological Association (APA) and the US Congress Office of Technology Assessment, that examined many scientific and measurement issues concerning integrity testing (e.g., validity, criterion relevance). Background data are offered on a variety of tests collected by a survey of test publishers, providing a view of the industry's scope (e.g., test audience, user screening, score reporting) not available elsewhere. In the light of APA's Ethical Principles for Psychologists and Code of Conduct (APA, 1992), unresolved concerns are addressed that have a wide range of implications for the profession of psychology, the testing industry, and public policy (e.g., cutting scores, user screening and training, and test marketing practices). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

地域通信网的干扰技术研究

本文在分析地域通信网结构及组成的基础上,研究了对地域通信网实施的节点破坏、末端信息封锁、局部阻塞瘫痪等对抗方法,并使用干扰地域通信网的程度、节点干扰率、末端节点封锁率和传递信息误差率等指标对干扰效果进行评估。