Inference problems in life testing under multivariate normality

Modified maximum likelihood estimators of the parameters of a multivariate normal distribution are developed when the smallest or largest observations on one of the components are censored. These estimators are used to construct tests for means and correlation coefficients. The robustness of these tests to deviations from normality is investigated.     

Ecology of urban lawns under three common management programs

Turfgrass lawns are a central part of urban and suburban landscapes throughout North America and are often managed using repeated applications of chemical fertilizers and pesticides. These inputs are expensive and may negatively affect ecological processes in lawns. Therefore, we evaluated the influence of three most common lawn care programs on ecological characteristics of turfgrass lawns. Twenty-eight home lawns, separated into 3 groups based on the lawn care program (professional, do-it-yourself [DIY], and no-input), were studied. Data on lawn quality, weed and insect infestation, disease incidence, soil nematode community, soil nitrogen pools, microbial biomass (MBN), and soil organic matter (SOM) were collected. Results indicated that professional lawn care resulted in the highest aesthetic lawn quality mainly due to better weed control, compared to DIY and no-input programs. However, professional and DIY programs negatively affected MBN and SOM pools and enhanced disease (rust) severity. No significant differences in soil nematode population and nematode community indices across the three programs were found, indicating no differences in net ecosystem productivity among the three programs. Overall, soil nematode food web in turfgrass lawns represented a disturbed food web compared to natural grasslands and forest ecosystems, irrespective of the lawn care program used.     

The narrative self in autobiographical accounts of illness

The paper analyzes autobiographical acounts of the experience of chronic illness and its treatment to develop a sociological theory of the self. It is suggested that ‘self’ is not a biologistic or psycologistic thing. Rather self is autobiographical narrative – hence the narrative self. It is argued that four elements constitute such narrative selves in autobiographical discourse: evaluative relationships between events in time; cosmology; power relationships; and conceptualisation of self as object.     

The assessment of parent-led prevention programs: a preliminary assessment of impact

This article reports on a preliminary study of the impact of parent-led prevention groups on youthful drug and alcohol use. In addition, the study assessed the extent to which families involved with parent-led prevention programs reported improved family relations and increased parental control of children's social activities--two major mechanisms by which parent-group advocates claim their activities alter youth substance use patterns. Consistent with the claims of parent-group advocates, the study results suggest that the parent groups did have some impact on family relations and on parental control of children's social activities. The evidence for an impact on drug and alcohol use was, however, weak. A somewhat unexpected finding was that parents who become involved in parent-led prevention activities may not be those parents whose children are at highest risk.     

DISTRIBUTION-FREE TESTS BASED ON SUB-SAMPLE EXTREMA FOR TESTING AGAINST POSITIVE DEPENDENCE

A class of distribution-free tests based on U-statistics has been proposed for testing the null hypothesis of independence against positive quadrant dependence. The tests are based on U-statistics and the Kendall's-tau test belongs to this class.     

Severity of illness: red herring or horse of different color? Part 2.

In this continuation of his article, the author defines severity and acuity of illness and discusses approaches to the measurement of the two factors. He provides some background on severity of illness measures that are in current use and prepares for a discussion of the uses of these measures.     

Child-rearing practices of two generations of Punjabi parents

The major objective of this article is to report the findings of two studies which compare and contrast the early child-rearing practices of two generations of Punjabi parents (1970s and 1990s) living in England. Additionally, the findings are compared with a small group of white mothers to broaden our understanding of the changing patterns of parenting. The data was collected through in-depth semi-structured interviews from the first generation during the period 1970–73 and from the second generation in 1995. The research perspective adopted is a qualitative one in that variables and procedures for data collection are not rigorously controlled, and the narratives of the mothers are used extensively to illuminate the key areas of early child rearing. The findings show that the second-generation mothers are shedding most of the traditional customs and practices and are moving towards modern British ways.     

A Formal Restatement of Durkheim's "Division of Labor" Theory

Despite frequent references in the sociological literature to Durkheim's theory about the division of labor, sociologists have made few attempts to test it. The paucity of attempts and the very debatable outcomes thereof are due largely to Durkheim's use of the traditional discursive mode of theory construction. A discursively stated theory's logical structure is likely to be obscure, and for that reason alone tests of it are difficult and controversial. Rather than perpetuate the exegetical tradition in sociological treatments of the subject, this paper restates Durkheim's theory in accordance with a particular formal mode. That restatement identifies the theory's shortcomings and problems. But the eight premises imply only one testable theorem, and the theorem's predictive accuracy appears minimal unless "population concentration" is substituted for "density" in the first axiom. Nonetheless, the restatement clearly shows how extension of the theory (additional postulates) could further its testability.