Understanding the implementation of a certain feature of a system requires identification of the computational units of the system that contribute to this feature. In many cases, the mapping of features to the source code is poorly documented. In this paper, we present a semiautomatic technique that reconstructs the mapping for features that are triggered by the user and exhibit an observable behavior. The mapping is in general not injective; that is, a computational unit may contribute to several features. Our technique allows for the distinction between general and specific computational units with respect to a given set of features. For a set of features, it also identifies jointly and distinctly required computational units. The presented technique combines dynamic and static analyses to rapidly focus on the system's parts that relate to a specific set of features. Dynamic information is gathered based on a set of scenarios invoking the features. Rather than assuming a one-to-one correspondence between features and scenarios as in earlier work, we can now handle scenarios that invoke many features. Furthermore, we show how our method allows incremental exploration of features while preserving the "mental map" the analyst has gained through the analysis.

Objective To measure the effect of free access to the scientific literature on article downloads and citations. Design Randomised controlled trial. Setting 11 journals published by the American Physiological Society. Participants 1619 research articles and reviews. Main outcome measures Article readership (measured as downloads of full text, PDFs, and abstracts) and number of unique visitors (internet protocol addresses). Citations to articles were gathered from the Institute for Scientific Information after one year. Interventions Random assignment on online publication of articles published in 11 scientific journals to open access (treatment) or subscription access (control). Results Articles assigned to open access were associated with 89% more full text downloads (95% confidence interval 76% to 103%), 42% more PDF downloads (32% to 52%), and 23% more unique visitors (16% to 30%), but 24% fewer abstract downloads (−29% to −19%) than subscription access articles in the first six months after publication. Open access articles were no more likely to be cited than subscription access articles in the first year after publication. Fifty nine per cent of open access articles (146 of 247) were cited nine to 12 months after publication compared with 63% (859 of 1372) of subscription access articles. Logistic and negative binomial regression analysis of article citation counts confirmed no citation advantage for open access articles.

Taking out student loans to assist with the costs of postsecondary schooling in the US has become the norm in recent decades. The debt burden young adults acquire during the higher education process, however, is increasingly stratified with black young adults holding greater debt burden than whites. Using data from the NLSY 1997 cohort, we examine racial differences in student loan debt acquisition and parental net wealth as a predictor contributing to this growing divide. We have four main results. First, confirming prior research, black young adults have substantially more debt than their white counterparts. Second, we find that this difference is partially explained by differences in wealth, family background, postsecondary educational differences, and family contributions to college. Third, young adults’ net worth explain a portion of the black–white disparity in debt, suggesting that both differences in accumulation of debt and ability to repay debt in young adulthood explain racial disparities in debt. Fourth, the black–white disparity in debt is greatest at the highest levels of parents’ net worth. Our findings show that while social and economic experiences can help explain racial disparities in debt, the situation is more precarious for black youth, who are not protected by their parents’ wealth. This suggests that the increasing costs of higher education and corresponding rise in student loan debt are creating a new form of stratification for recent cohorts of young adults, and that student loan debt may be a new mechanism by which racial economic disparities are inherited across generations.

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We find little empirical support for the pain- and distress-based explanations for rising mortality in the US White population. Instead, recent mortality increases among younger and middle-aged US White men and women have likely been shaped by the US opiate epidemic and an expanding obesogenic environment.