Improved randomized response in additive scrambling models

Randomized response models deal with stigmatizing variables appearing in health surveys. Additive and subtractive scrambling in split sample and double response yield unbiased mean and sensitivity estimators of high precision. The split sample method is protective of privacy. The double response method is as protective only conditionally. To achieve the maximum efficiency, the scrambling variables must be similar to each other and the probability of obtaining a true response must be as large as possible. The randomized response procedures yield more efficient estimates of the average total number of classes missed by university students.     

Open Order Rescheduling in Job Shops with Demand Uncertainty: A Simulation Study

This paper addresses the problem of open order rescheduling in a job shop. Results are reported of experiments conducted in a simulation model of an 8-machine job shop. Four different order updating policies are examined. The due-date process is modeled to include several realistic features about the pattern of due-date variability. These features are parameterized and tested at several levels. Tardiness results indicate that open order rescheduling is beneficial only when allowances are loosely set. The results indicate that inventory performance is improved by order rescheduling, particularly in cases when due dates are revised to earlier times than originally forecast.     

Urbanization-related distribution patterns and habitat-use by the marine mesopredator,giant Pacific octopus (<Emphasis Type="Italic">Enteroctopus dofleini</Emphasis>)

Urbanization is a process that heavily alters marine and terrestrial environments, though terrestrial urban ecosystems have been studied far more intensively. Terrestrial studies suggest that urbanization can facilitate mesopredators by enhancing food and shelter resources and reducing predation pressure from apex consumers. This in turn has considerable consequences for ecological communities. We evaluated spatial distribution patterns and habitat-use of the marine mesopredator, giant Pacific octopus (Enteroctopus dofleini), relative to terrestrial urbanization intensity in Puget Sound, Washington, USA. Using field surveys and citizen-contributed data for E. dofleini, we examined whether: (1) Distribution was related to urbanization, (2) Abundance was related to the extent of benthic anthropogenic debris, and (3) Diet differed as a function of urbanization and den cover. Our results suggest that urbanization impacts may differ with depth. Mixed-effects logistic regression model estimates for the probability of occurrence increased with urbanization in deep-water (> 24 m), and decreased with urbanization in shallow water (< 18 m). Accompanying field surveys indicated that E. dofleini abundance was correlated with the number of benthic anthropogenic debris items, and that E. dofleini diets were not affected by urbanization intensity or den cover. Though E. dofleini may be synanthropic within certain urban environments, the mechanisms driving this pattern likely differ from those affecting common urban mesopredators on land, with den provisioning from man-made structures being more important than altered food resources.     

Problem Gambling and Delinquent Behaviours Among Adolescents: A Scoping Review

Despite many studies indicating an association between problem gambling and delinquent behaviours among adolescents, there has been no effort to systematically analyze the state of the literature on this relationship. To fill this gap, we conducted a scoping review of the literature published between 2000 and 2016 on problem gambling and delinquent behaviours among adolescents. We searched twelve databases and reviewed reference lists to identify eligible studies. Search terms included a combination of medical subject headings and keywords for gambling, youth, and delinquency, which were combined with the Boolean operator “AND”. 1795 studies were identified through the literature search. Nine studies were eligible for inclusion. All of the studies were conducted in North America, with primarily male participants, and most of the data were cross-sectional. No qualitative studies met the inclusion criteria. Screening tools used to measure problem gambling were inconsistent, making comparisons across studies difficult. We found a consistent moderate to strong association between problem gambling and delinquent behaviour. Only one study presented associations by socio-economic status and none considered gender, sex or ethnic differences. Studies in the review showed that problem gambling is associated with both violent and non-violent behaviours among adolescents. These associations may suggest that problem gambling and delinquent behaviours have common risk factors and reflect a syndrome of risky behaviours best targeted through prevention and treatment that is holistic and considers the context in which the youth is situated. Further research is warranted to better understand the relationship between problem gambling and delinquent behaviours.     

Ground beetle (Coleoptera: Carabidae) communities on green roofs in Switzerland: synthesis and perspectives

Urban Ecosystems - Green roofs have recently gained recognition for their potential contribution to urban ecosystems by providing, among other services, habitat for plants and animals, and stepping...     

Professionalization through attrition? An event history analysis of mortalities in citizen journalism

ABSTRACT

Despite both scholarly and popular claims that citizen journalism (CJ) represents a growing democratizing force in the journalistic field, recent scholarship in the area has noted the decline of the organizational population of CJ. In this paper, we investigate how individual characteristics of sites and the dynamics of larger organizational population affect a CJ site’s risk of experiencing a mortality. Drawing on the largest sample to date of US-based English-language CJ sites, this study examines the risk of site mortality through an event history framework. Findings indicate that the strongest predictor of a site’s mortality is the age of the site, consistent with organizational population theory’s ‘liability of newness.’ We also find that for-profit and community-based sites have lower rates of site mortality, indicating that adopting legitimate conventions of journalism may serve as a protective buffer to site death. The results offer mixed evidence on whether CJ has become more professionalized via attrition.     

Life satisfaction in China and consumption and income inequalities

This research uses nationally representative data to study how economic resources and inequalities are associated with life satisfaction of Chinese residents. We construct economic resource and inequality measures from expenditure rather than from income, after confirming that expenditure inequality is a better measure in the Chinese context. We find that economic inequalities in general are negatively associated with life satisfaction, and that this association is larger for inequalities in the lower half of the distribution than those in the upper half of the distribution. We further explore the mechanisms under which inequality can be associated with life satisfaction, and find that aspiration is potentially one important channel.     

A martingale-based test for independence of time to failure and cause of failure for competing risks models

In this article, we introduce a class of tests, using a martingale approach, for testing independence of failure time and cause of failure for competing risks data. Asymptotic distribution of the proposed test statistic is derived. The procedure is illustrated with a real-life data. A simulation study is carried out to assess the level and power of the test.