分布式数据库操作中的并行控制理论与算法

讨论了分布式数据库操作中的并发控制理论与模型，给出了操作的可串行化原理，并提供了几种并发控制算法：基于锁方法，基于时间标记方法以及最佳锁定法。     

Braided composite materials for the production of lightweight, high rigidity golf shafts

Braiding is not currently used in the production of golf shafts. The objective of this work was to develop, through a modelling process consisting of altering lamina sequence, a golf shaft, using braided laminas, which would have mass, stiffness and torque comparable to commercially available composite and steel shafts. A 2D conical braided composite model was previously developed and validated to predict elastic constants of braided closed meshed structures. Energy methods were used to calculate the stiffness and torque of shafts using prescribed industry approaches. Shaft mass was calculated based on geometry and density of constitutent materials. Modelled shafts had both braided and unidirectional layers and compared favourably with or were better than commercially available composite and steel shafts in terms of deflection force and twist angle; they had the same weight as composite shafts but were much lighter than steel shafts. If these findings are verified, braided composites would be a viable and effective approach to the design of future golf shafts.     

关于运动性猝死的原因及预防

运动性猝死在人类历史的长河中屡见不鲜,在体育场上发生的一系列运动性猝死事件震撼了国际体坛,引起了人们极大的关注.在查阅了国内外有关运动性猝死的大量文献后发现,猝死的发生率男性多于女性,30岁以下为高峰,死亡原因以心源性猝死最为多见,脑源性猝死在运动也时有发生.针对我国运动猝死的发生情况提出相应的预防措施.     

Update on inflation of journal prices: medical journals, U.S. journals, and Brandon/Hill list journals

This paper examines the increases in prices for the last twenty years for the journals listed in the 1987 Brandon/Hill list and for the last twelve years for those on a list of medical and general periodicals published annually in Library Journal. This information is compared to the general U.S. inflation rate as measured by the Consumer Price Index. Despite the decline in the general rate of inflation, the buying power of libraries has continued to dwindle. Librarians need to use this information when justifying increased budget requests. They also need to interact more effectively with publishers to resolve this problem. The buying power of the dollar (as compared to the 1975 dollar) spent on the Brandon/Hill list journals is now 59% of that of a dollar spent in the general economy. This compares to 64% in 1983, when this research was last updated.     

Establishing reliability of biomechanical data using univariate and multivariate approaches

The purpose of this study was to use generalizability theory with both univariate and multivariate approaches to examine reliability of total body center of mass (CM) values calculated from cinematographical data. Twenty-eight college-aged male volunteers were filmed by a LOCAM camera at 100 fps while performing the basic locomotion skill of walking. Film analysis was conducted on each subject using six frames of film depicting a one-stride walking cycle consisting of right heel strike, right foot flat, left toe-off, left heel strike, left foot flat, and right toe-off. Nineteen segmental endpoints and a reference point were digitized by three experienced plotters. The digitizing sequence was replicated three times by each plotter. A FORTRAN program calculated nine CM values (three plotters by three repetitions) for each subject filmed in each of the six positions of the stride. The x- and y-coordinates of the CM values were the dependent variables analyzed by fully crossed 3-way univariate and multivariate ANOVAs (subjects by plotters by repetitions). All measurement facets were considered to be random. Results indicate that there was very little repetition error but considerable interplotter error for most frames. Phi-coefficients for x- and y-coordinates, separately, fluctuated across frames. The univariate values for the x-coordinates were similar but slightly less than the multivariate values. The Phi-coefficients for Y, however, were considerably lower than the multivariate values. The multivariate Phi-coefficients for generalizing over three plotters and three repetitions ranged from .82 to .90.(ABSTRACT TRUNCATED AT 250 WORDS)