Content contribution from individuals is critical to the viability of online communities. In this study we identify the factors that are associated with the quantity and the quality of content sharing in a photo sharing community, where the act of content creation is decoupled from the act of content sharing. We draw on theories of intrinsic and extrinsic motivation, and find that the prospect ...

This paper addresses the problem of the evaluation of people counting systems. The relation between the real people number and the output of the people counting system is used to motivate the computation of the maximum number of people as a scenario and geometry specific quantity which supports the evaluation of the system output. Based on the camera field-of-view we determine the maximum numbe...

DNA methylation is a well-characterized epigenetic modification that plays an important role in the regulation of gene expression. There is growing evidence on the involvement of epigenetic mechanisms in disease onset, including cancer. Environmental factors seem to induce changes in DNA methylation affecting human health. However, little is known about basal methylation levels in healthy peopl...

n engl j med 362;18 nejm.org may 6, 201

Background--Healthy People 2010 (HP2010) objectives are based on two overarching goals: 1) to increase years and quality of healthy life, and 2) to eliminate disparities among subgroups of the population. Four hundred and sixty-seven specific objectives consistent with these goals were outlined, baseline data were identified when available, and specific targets were set for the year 2010. This ...

As part of the continuing evaluation of the health of Americans, a midcourse review of the Healthy People 2000 objectives (1) added several new objectives and identified changes to some of the objectives released in 1990 (2). The midcourse review also documented numerous previous revisions to Healthy People 2000 baselines (3) and the setting of new targets for some objectives. The purpose of th...

Virtually all human disease is induced by oxidative stress. Oxidative stress, which is caused by toxic environmental exposure, the presence of disease, lifestyle choices, stress, chronic inflammation or combinations of these, is responsible for most disease. Oxidative stress from all sources is additive and it is the total oxidative stress from all sources that induces the onset of most disease...