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Spoth Richard; Trudeau Linda; Guyll Max; Shin Chungyeol; Redmond Cleve 《Canadian Metallurgical Quarterly》2009,77(4):620
In this article, the authors examine whether delayed substance initiation during adolescence, achieved through universal family-focused interventions conducted in middle school, can reduce problematic substance use during young adulthood. Sixth-grade students enrolled in 33 rural midwestern schools and their families were randomly assigned to 3 experimental conditions. Self-report questionnaires provided data at 7 time points for the Iowa Strengthening Families Program (ISFP), Preparing for the Drug Free Years (PDFY), and control groups through young adulthood. Five young adult substance frequency measures (drunkenness, alcohol-related problems, cigarettes, illicit drugs, and polysubstance use) were modeled as distal outcomes affected by the average level and rate of increase in substance initiation across the adolescent years in latent growth curve analyses. Results show that the models fit the data and that they were robust across outcomes and interventions, with more robust effects found for ISFP. The addition of direct intervention effects on young adult outcomes was not supported, suggesting long-term effects were primarily indirect. Relative reduction rates were calculated to quantify intervention-control differences on the estimated proportion of young adults indicating problematic substance use; they ranged from 19% to 31% for ISFP and from 9% to 16% for PDFY. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Max ben-Aaron 《控制论与系统》2013,44(2):25-33
The deferred-updating cybernetic theory of the mind/brain information-processing system was devised to explain the purpose of sleep [2]. This theory predicts the existence of an intermediate memory, the circadian memory [14]. This is different from, and auxiliary to, both short-term and long-term mem⊙ry. One of the prime functions of circadian memory, according to the theory, is to store incoming information until it can be integrated into long-term memory. This takes place during sleep, the purpose of which, from an information-processing point of view, is to allow the system to go off-line to accomplish the integration. 相似文献
56.
Most carbon-type seal materials contain graphitic carbon as the minor constituent. Materials having graphite carbon as the major constituent were studied as possible seal materials at 10,000 feet per minute sliding velocities, in most experiments the temperature of the mating surfaces was 500°F. Carbon materials made graphitic by electro-graphitization were too soft; they gave high wear and high friction. Bodies molded with high-graphite-content materials and made hard by improved molding methods and impregnation gave acceptable friction and wear properties. When a hardenable stainless steel was used, the effect of varied hardness of mating surface on wear of typical carbon was slight. Within a limited range, roughness of mating surface is not important to wear of carbons. 相似文献
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1 引言 由"国家电信局"(National Telecommunications Agency,Anatel)主持的数字电视在巴西的首次"公开咨询报告"(Public Consultation)的一年后,我们注意到:在这种技术的领域内,已经出现很多不同的显著事实.除了"CPqD基金会"报告以外,新的对比性测试曾经在美国(ATSC对DVB-T)和中国香港(ATSC,DVB-T和ISDB-T)都进行过.还有一些报道表明:中国台湾也进行了对比性测试,目的是确立自己的数字电视标准. 相似文献
58.
Centroidal Voronoi Tessellation Algorithms for Image Compression, Segmentation, and Multichannel Restoration 总被引:1,自引:0,他引:1
Qiang Du Max Gunzburger Lili Ju Xiaoqiang Wang 《Journal of Mathematical Imaging and Vision》2006,24(2):177-194
Centroidal Voronoi tessellations (CVT's) are special Voronoi tessellations for which the generators of the tessellation are
also the centers of mass (or means) of the Voronoi cells or clusters. CVT's have been found to be useful in many disparate
and diverse settings. In this paper, CVT-based algorithms are developed for image compression, image segmenation, and multichannel
image restoration applications. In the image processing context and in its simplest form, the CVT-based methodology reduces
to the well-known k-means clustering technique. However, by viewing the latter within the CVT context, very useful generalizations
and improvements can be easily made. Several such generalizations are exploited in this paper including the incorporation
of cluster dependent weights, the incorporation of averaging techniques to treat noisy images, extensions to treat multichannel
data, and combinations of the aforementioned. In each case, examples are provided to illustrate the efficiency, flexibility,
and effectiveness of CVT-based image processing methodologies.
Qiang Du is a Professor of Mathematics at the Pennsylvania State University. He received his Ph.D. from the Carnegie Mellon University
in 1988. Since then, he has held academic positions at several institutions such as the University of Chicago and the Hong
Kong University of Science and Technology. He has published over 100 papers on numerical algorithms and their various applications.
His recent research works include studies of bio-membranes, complex fluids, quantized vortices, micro-structure evolution,
image and data analysis, mesh generation and optimization, and approximations of partial differential equations.
Max Guzburger is the Frances Eppes Professor of Computational Science and Mathematics at Florida State University. He received his Ph.D.
degree from New York University in 1969 and has held positions at the University of Tennessee, Carnegie Mellon University,
Virginia Tech, and Iowa State University. He is the author of five books and over 225 papers. His research interest include
computational methods for partial differential equations, control of complex systems, superconductivity, data mining, computational
geometry, image processing, uncertainty quantification, and numerical analysis.
Lili Ju is an Assistant Professor of Mathematics at the University of South Carolina, Columbia. He received a B.S. degree in Mathematics
from Wuhan University in China in 1995, a M.S. degree in Computational Mathematics from the Chinese Academy of Sciences in
1998, and a Ph.D. in Applied Mathematics from Iowa State University in 2002. From 2002 to 2004, he was an Industrial Postdoctoral
Researcher at the Institute of Mathematics and Its Applications at the University of Minnesota. His research interests include
numerical analysis, scientific computation, parallel computing, and medical image processing.
Xiaoqiang Wang is a graduate student in mathematics at the Pennsylvania State University, working under the supervision of Qiang Du. Starting
in September 2005, he will be an Industrial Postdoctoral Researcher at the Institute of Mathematics and its Applications at
the University of Minnesota. His research interests are in the fields of applied mathematics and scientific computation. His
work involves numerical simulation and analysis, algorithms for image processing and data mining, parallel algorithms, and
high-performance computing. 相似文献
59.
Entry costs to home ownership have been rising in Australia since the mid‐1950s but home ownership rates had not fallen by the mid‐1980s. Drawing from a national life history survey carried out in 1986–87, this paper shows that median ages for first time home buying have been declining among successive cohorts over the post‐war era. The paradox of rising entry costs and earlier home buying may be explained by rising labour force participation among women immediately after marriage and awareness of the increasing financial returns from long‐term home ownership. Among the later cohorts, early entry to home ownership appears to have been associated particularly strongly with wives' employment after marriage and husbands' incomes. The findings suggest that access to home ownership in the future may be increasingly limited to young adults having high household incomes. 相似文献
60.
BACKGROUND: Topical application of inhibitors of HMGCoA reductase, the rate-limiting enzyme of cholesterol synthesis, has been shown to induce impairment of barrier function. OBJECTIVE: Assessing whether oral administration of statins used for reducing blood levels of cholesterol induces functional changes in stratum corneum barrier. MATERIALS AND METHODS: 69 subjects of both sexes under-going treatment for hypercholesterolemia (mean age 48 +/- 11 years) entered the study; 43 had been treated with simvastatin and 11 with pravastatin for 6 months; 15 only on dietary regimen served as controls. Efficiency of stratum corneum water barrier was evaluated by transepidermal water loss (TEWL) measurement using an evaporimeter; water-holding capacity of the stratum corneum was assessed by the sorption-desorption test measured by capacitance. Statistical analysis was performed using ANOVA. RESULTS: No differences were found between the groups (simvastatin, pravastatin, diet) concerning both basal TEWL and the dynamic of water binding in the stratum corneum. CONCLUSIONS: Prolonged treatment with cholesterol-lowering drugs based on inhibition of HMGCoA reductase does not alter the permeability barrier of the skin. 相似文献