Effects of physical and mental demands on shoulder muscle fatigue

Mental demands have been associated with increased risk of injuries; however, its influence on muscle fatigability remains unclear. The aim of this study was to investigate the interaction of mental workload and physical workload on muscle fatigability during repetitive shoulder work. Twelve young participants, balanced by gender, performed shoulder abduction exercises until exhaustions at three levels of physical workload (low (5% maximum voluntary contraction (MVC)), moderate (35% MVC), and high (55% MVC)) in the absence and presence of a mental arithmetic test. Endurance time and rate of strength decline were employed as indicators of muscle fatigue. Concurrent physical and mental processing was found to adversely decrease muscle endurance by ~25% at the moderate intensity level. Furthermore, concurrent demands were associated with faster rate of strength decline compared to the control, irrespective of the physical intensity level. Findings from the current study provide evidence of the adverse effects of mental workload on muscle capacity (i.e., endurance and fatigue). It is therefore important to consider potential changes in worker capacity with concurrent physical and cognitive demands before designing work tasks/products.     

A Multiple Three-Decision Procedures for Comparing Several Treatments with a Control Under Heteroscedasticity

In this article, the design-oriented two-stage multiple three-decision procedure is proposed to classify a set of normal populations with respect to a control under heteroscedasticity. The statistical tables of percentage points and the power-related design constants, to implement our new two-stage procedure, are given. Sometimes when the sample for the second stage is not available, the one-stage data analysis procedure is proposed. Classifying a treatment better than control when it is actually worse (and vice versa) is known as type III error. Both the two-stage and one-stage procedures control the type III error rate at a specified level. The relationship between the two-stage and one-stage procedures is discussed. Finally, the application of the proposed procedures is illustrated with an example.     

Generalized Scrambling in Quantitative Optional Randomized Response Models

Huang (2010 Huang , K. C. ( 2010 ). Unbiased estimators of mean, variance and sensitivity level for quantitative characteristics in finite population sampling . Metrika 71 : 341 – 352 .[Crossref], [Web of Science ®] , [Google Scholar]) proposed an optional randomized response model using a linear combination scrambling which is a generalization of the multiplicative scrambling of Eichhorn and Hayre (1983 Eichhorn , B. H. , Hayre , L. S. ( 1983 ). Scrambled randomized response methods for obtaining sensitive quantitative data . J. Statist. Plann. Infer. 7 : 307 – 316 .[Crossref], [Web of Science ®] , [Google Scholar]) and the additive scrambling of Gupta et al. (2006, 2010). In this article, we discuss two main issues. (1) Can the Huang (2010 Huang , K. C. ( 2010 ). Unbiased estimators of mean, variance and sensitivity level for quantitative characteristics in finite population sampling . Metrika 71 : 341 – 352 .[Crossref], [Web of Science ®] , [Google Scholar]) model be improved further by using a two-stage approach?; (2) Does the linear combination scrambling provide any benefit over the additive scrambling of Gupta et al. (2010 Gupta , S. N. , Shabbir , J. , Sehra , S. ( 2010 ). Mean and sensitivity estimation in optional randomized response models . J. Statist. Plann. Infer. 140 : 2870 – 2874 .[Crossref], [Web of Science ®] , [Google Scholar])? We will note that the answer to the first question is “yes” but the answer to the second question is “no.”     

Projecting the Effect of Changes in Smoking and Obesity on Future Life Expectancy in the United States

We estimate the effects of declining smoking and increasing obesity on mortality in the United States over the period 2010–2040. Data on cohort behavioral histories are integrated into these estimates. Future distributions of body mass indices are projected using transition matrices applied to the initial distribution in 2010. In addition to projections of current obesity, we project distributions of obesity when cohorts are age 25. To these distributions, we apply death rates by current and age-25 obesity status observed in the National Health and Nutrition Examination Survey, 1988–2006. Estimates of the effects of smoking changes are based on observed relations between cohort smoking patterns and cohort death rates from lung cancer. We find that changes in both smoking and obesity are expected to have large effects on U.S. mortality. For males, the reductions in smoking have larger effects than the rise in obesity throughout the projection period. By 2040, male life expectancy at age 40 is expected to have gained 0.83 years from the combined effects. Among women, however, the two sets of effects largely offset one another throughout the projection period, with a small gain of 0.09 years expected by 2040.     

Polarized Scientists? Exploring Political Differences about Religion and Science among U.S. Biologists and Physicists1

From the Texas textbook debate to the March for Science, visible displays of activism illuminate how deeply politicized the science‐religion interface has become. However, little is known about the extent to which scientists’ attitudes about science and religion are politicized. Using original survey data from 1,989 U.S. academic biologists and physicists, we examine the degree to which political views shape how scientists perceive the relationship between religion and science, religious authority, their personal religious identity, and views on dominant scientific theories. Findings suggest that, indeed, the science‐religion interface holds political meaning for scientists, but in different ways across the political spectrum. Specifically, for politically liberal scientists, atheism and the conflict narrative are particularly politicized belief structures, while politically conservative scientists emphasize religious identity to distinguish themselves from political liberals. Findings point to the critical role of politics in shaping scientists’ attitudes and identities, which may have implications for the scientific enterprise, both at the lab bench and in the political sphere.     

A Class of Two-Stage Selection Procedures Using L-Statistics

Summary: A class of selection procedures for selecting the least dispersive distribution from k available distributions has been proposed. This problem finds applications in reliability and engineering. In engineering, for example, the goal of the experimenter is to select a firm whose components have least dispersive distribution from the available set of competing firms manufacturing the components of the desired specifications meant for the same purpose. The proposed procedures can be used even when the underlying distributions belong to different families. Applications of the proposed selection procedures are discussed by taking exponential, gamma and Lehmann type distributions. Performance of the proposed selection procedures is assessed through simulation study. Implementation of the proposed selection procedure is illustrated through an example. * The authors are very grateful to the editor and referees for their valuable comments.     

Acceptance of Foreigners: Ethnic and Gender Differences Among Americans

This study examined American students' (N = 207) attitudes and behavior towards students of various nationalities. The findings suggest that, while these students rated Africans lower than Westerners, and Asians no differently than the other two groups, there were ethnic and gender differences among the Americans. Female students rated Westerners as being better liked than Africans, and minority students rated Westerners both as better liked and better adjusted than Africans. Males and Whites rated the three groups equally. Overall ratings by women were more favorable than those by men. In terms of volunteering hospitality, these students were as generous to the Asian and the African foreigners as to the Westerners, but in general, a greater proportion of ethnic minority students was willing to be hospitable.     

Gender and changing generational relations: Spouse choice in Indonesia

Many Asian societies are undergoing a nuptiality transition that is not only tied integrally to other aspects of family organization, but is also often more complex than standard studies of female age at marriage can reveal. To comprehend some of this complexity, we focus on the patterns of spouse choice for both men and women in central Java. The extent of parental control over mate selection is examined for change over time, gender differences, and likely determinants, including family class, education, premarital work, and residence. It is argued that the current marriage transition in Indonesia reflects both gender and generational hierarchies in the Javanese family system. The analysis is conducted using a multinomial logit model; in general, it yields results strongly supportive of the argument that the determinants of spouse selection differ by gender. The results also show that although there is a dramatic shift towards self-choice marriages, it is occurring within the context of historical and institutional factors specific to Javanese society.     

Sample registration in gujarat,india

Since October, 1965, births and deaths in rural Gujarat State, India, have been recorded under two independent systems in a random sample of units. First, a part-time local "registrar" is appointed in each sample unit (village or segment thereof) who: prepares a house list; conducts a baseline survey showing the individuals in each household; and maintains a list of the vital events reported by informants whom he contacts fortnightly. Second, a staff member at the rural health centre is assigned part-time supervisory and survey duties: to check the initial listings of the registrar; thereafter, to inspect the registrar's records at least quarterly; and to conduct a household survey each six months, updating the household register and recording births and deaths independently. The registrar's list is sent to the district office immediately before the survey, where it is matched with the survey list forwarded by the local supervisor. A list of unmatched events is returned to the supervisor who with the registrar revisits households to resolve the discrepancies. Under-registration is estimated to be 13 to 20 percent by the registrar method, 8 to 17 percent by the survey method. The birth rate is estimated to be about 44 and the death rate about 19.     

The existence of moments of ridge-like k-class and partially restricted reduced form estimators

I n Sway and Mehta (1980) it was shown that when the number of included endogenous variables i n a structural equation i s two then a ridge-like k-class estimator' with 02 k 2 1 possesses moments o f all order .in the normal case. I n this note we extend those results to the case where the equation contains more than two endogenoustract.