Using capture-recapture analysis we estimate the effective size of the active Amazon Mechanical Turk (MTurk) population that a typical laboratory can access to be about 7,300 workers. We also estimate that the time taken for half of the workers to leave the MTurk pool and be replaced is about 7 months. Each laboratory has its own population pool which overlaps, often extensively, with the hundreds of other laboratories using MTurk. Our estimate is based on a sample of 114,460 completed sessions from 33,408 unique participants and 689 sessions across seven laboratories in the US, Europe, and Australia from January 2012 to March 2015.

The 1,080 km2 Batang Gadis National Park in the North Sumatra province of Indonesia was established in December 2004 by the regional government of Mandailing Natal district. The Park has the potential to make an important contribution to tiger conservation but lacks scientific data on the occurrence of the species. This study aimed to assess the tiger population of the Park, using camera trapping conducted between December 2005 and July 2006. We recorded a mean tiger density of 1.8 tigers per 100 km2 (95% CI 1.8–6.4) and, based on this, estimated the tiger population in and adjacent to the Park to be 29–103 adults. We found that tiger presence was negatively correlated with altitude and positively correlated with distance from forest edge to the interior, and < 18% of the total suitable habitat occupied by tigers was of high quality. This study indicates that Batang Gadis National Park potentially serves as a natural corridor betwen the Angkola and Barumun-Rokan ecosystems, areas totalling c. 6,500 km2, and that this landscape could serve as a stronghold for tiger populations in northern Sumatra.

To obtain information on density of tiger Panthera tigris in selectively logged forest, a 9-month camera-trapping survey was conducted over elevations of 190–850 m in lowland and hill/upper dipterocarp and lower montane forests in Gunung Basor Forest Reserve, Peninsular Malaysia. Capture-recapture sampling methods were used to estimate tiger population density in the Reserve. The number of individual tigers captured was six. Using the Mh jackknife estimator the average capture probability per sampling occasion was 0.28 and the corresponding estimate of population size 8 ± SE 1.89. The overall probability of photo-capturing a tiger present in the sampled area was 0.75. Using an approach based on distances between photo-captures, a buffer width of 3.22 km and an effectively sampled area of 308 km2 was estimated. This resulted in a density estimate of 2.59 ± SE 0.71 adult tigers per 100 km2. The results indicate that selectively logged forests such as Gunung Basor Forest Reserve have the potential to accommodate a high density of tigers. Decision makers and conservation planners should not therefore perceive selectively logged forests to have limited conservation value. Further research on the ecology of tigers and their prey in selectively logged forests is urgently needed. Such research would enable conservationists to recommend tiger-friendly management guidelines for sustainable forest management and thereby significantly contribute to tiger conservation in Malaysia.

When a disaster occurs, a major difficulty is knowing where to find accurate information, and how to help coordinate efforts to share accurate information in a quick and organized manner. The establishment of a global information network, that is in place before a disaster occurs, could link all the communication efforts for relief. We propose that a Global Health Unit for Disaster and Relief Coordination be set up as part of the Global Health Network, utilizing the Internet as its backbone. This Unit would establish the links for the disaster information mosaic.