Parallel query processing with zigzag trees

In this article, we describe our approach to the compile-time optimization and parallelization of queries for execution in DBS3 or EDS. DBS3 is a shared-memory parallel database system, while the EDS system has a distributed-memory architecture. Because DBS3 implements a parallel dataflow execution model, this approach applies to both architectures. Using randomized search strategies enables the exploration of a search space large enough to include zigzag trees, which are intermediate between left-deep and right-deep trees. Zigzag trees are shown to provide better response time than right-deep trees in case of limited memory. Performance measurements obtained using the DBS3 prototype show the advantages of zigzag trees under various conditions.     

Long-term functional outcome following transient middle cerebral artery occlusion in the rat: Correlation between brain damage and behavioral impairment.

The assessment of both histological and functional long-term outcomes after cerebral ischemia is increasingly recommended for preclinical studies. Whereas correlations between behavioral impairments and primary ischemic lesion are documented, little is known about their relationships with remote nonischemic regions that undergo secondary degeneration, such as the thalamus. Anesthetized rats were subjected to mild (30 min) or severe (60 min) occlusion of the middle cerebral artery. Two months after ischemia, sensorimotor behavior was assessed according to the neurological score, limb-placing, adhesive-removal, and staircase tests; the final histological lesion was measured after this assessment. Cortical damage was correlated to all transient and long-lasting sensorimotor deficits, whereas striatal lesion was more consistently reflected by the forelimb-placing reflexes and adhesive-removal motor deficits. By contrast, the thalamic atrophy was not correlated to early neurological impairment, but rather to the late sensory deficit at the adhesive-removal test and to the skilled forepaw reaching alteration at the staircase test. This suggests that thalamus contributes, albeit moderately, to the ischemia-induced long-lasting sensorimotor deficits, some of which represent relevant targets for therapeutic interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Technical Word- and Term-Translation Aid Using Noisy Parallel Corpora across Language Groups

Technical-term translation represents one of the most difficult tasks for human translators since (1) most translators are not familiar with terms and domain-specific terminology and (2) such terms are not adequately covered by printed dictionaries. This paper describes an algorithm for translating technical words and terms from noisy parallel corpora across language groups. Given any word which is part of a technical term in the source language, the algorithm produces a ranked candidate match for it in the target language. Potential translations for the term are compiled from the matched words and are also ranked. We show how this ranked list helps translators in technical-term translation. Most algorithms for lexical and term translation focus on Indo-European language pairs, and most use a sentence-aligned clean parallel corpus without insertion, deletion or OCR noise. Our algorithm is language- and character-set-independent, and is robust to noise in the corpus. We show how our algorithm requires minimum preprocessing and is able to obtain technical-word translations without sentence-boundary identification or sentence alignment, from the English–Japanese awk manual corpus with noise arising from text insertions or deletions and on the English–Chinese HKUST bilingual corpus. We obtain a precision of 55.35% from the awk corpus for word translation including rare words, counting only the best candidate and direct translations. Translation precision of the best-candidate translation is 89.93% from the HKUST corpus. Potential term translations produced by the program help bilingual speakers to get a 47% improvement in translating technical terms.     

Three‐dimensional flow dynamics around deflectors

Many river rehabilitation projects to enhance the aquatic habitat focus on the creation of pool and riffle habitat by the implementation of flow deflectors, with various degrees of successes and failures. A more comprehensive understanding of the complex three‐dimensional flow dynamics that induces scour around instream structures is required for a more effective design. The objective of this study is to examine the three‐dimensional mean and turbulent flow characteristics around paired flow deflectors for various types of deflector design in a laboratory flume. Three deflector angles (45°, 90° and 135°) and two deflector heights (with flow under and over the deflector height) were tested over a smooth (plexiglas) bed and a sand bed. Three‐dimensional velocity measurements were taken with an acoustic Doppler velocimeter at several planform positions at two heights above the bed. Results show that the 90° deflectors create the most important disturbance in the mean flow field, in turbulence intensity and bed shear stress. There is, however, a marked difference in the spatial distribution of the mean and turbulent parameters over a mobile bed and over a smooth, fixed bed. This stresses the importance of understanding the feedback between bed topography and flow dynamics and limits the applicability of conclusions drawn from plane bed experiments to natural rivers. Copyright © 2005 John Wiley & Sons, Ltd.     

Experimental study of heat transfer in oscillating flow

This paper describes an experimental study of heat transfer in oscillating flow inside a cylindrical tube. Profiles of temperature are taken inside the wall and in the fluid from an instrumented test rig, in different conditions of oscillating flow. Profiles obtained allow the observation of the wall effect on heat transfer. A method using the inverse heat conduction principle allows the characterization of local heat transfers at the fluid-solid interface. Finally, a comparison between global and local approaches of heat transfer shows the difficulty of defining a dimensionless heat flux density to model local heat transfer in oscillating flow.     

The Influence of C60 Powders On Cultured Human Leukocytes

In order to check its possible acute toxicity, C₆₀ was incorporated into living human phagocytes. It was observed that C₆₀ has no influence on the survival of human leukocytes.     

Knowledge and beliefs regarding the consequences of cigarette smoking and their relationships to smoking status in a biracial sample.

198 men and 413 women responded to random telephone surveys in Fargo, North Dakota and Memphis, Tennessee. Each S was given the Smoking Attitudes Survey, which assesses generalized health beliefs and health-related problems associated with smoking. Ss' knowledge of smoking-associated diseases and diseases not associated with smoking was also assessed. Stepwise regression analysis of composite knowledge scores revealed 4 predictors of the health consequences of smoking: education, race, smoking status, and income. Smokers reported less knowledge and less concern about health consequences of smoking, were more likely to be male, and were more concerned about health consequences of cholesterol. The best predictor of smokers who had never attempted cessation was their greater concern over weight control, compared with smokers with a history of smoking-cessation attempts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)