BACKGROUND Estimation of the size of hidden and hard-to-reach sub-populations, suchas drug-abusers, is a very important but difficult task. Network scale up(NSU) is one of the indirect size estimation techniques, which relies onthe frequency of people belonging to a sub-population of interest amongthe social network of a random sample of the general population. In thisstudy, we estimated the so...

Acropora pruinosa is a threatened zooxanthellate scleractinian coral that distributed in the temperate areas along coastline of Japan and northern area South China Sea. Since A. propagates both asexually sexually, assessing clonal diversity genetic connectivity among populations important for conservation. In addition, high morphological variations field create confusion during species identifi...

In this paper we consider the estimation of population size from one-source capture–recapture data, that is, a list in which individuals can potentially be found repeatedly and where the question is how many individuals are missed by the list. As a typical example, we provide data from a drug user study in Bangkok from 2001 where the list consists of drug users who repeatedly contact treatment ...

Particle data from two geosynchronous satellites (Applied Technology Satellite 6 and SCATHA) show a normally hidden ion population appearing when the satellites are in the earth's shadow. Ion and electron data show the spacecraft potential dropping from +10 V in sunlight to +4 to +5 V in eclipse at local midnight, in low-energy (T < 1 keV) plasma sheet environments. During eclipse, a cold (T = ...

Rowland Atkinson and John Flint are researchers at the Department of Urban Studies, University of Glasgow. Both have an interest in the spatial distribution and experience of social exclusion and have been commissioned to devise a methodology for tracing residents who leave regeneration areas in Scotland. •In its simplest formulation snowball sampling consists of identifying respondents who are...

Adequate surveillance of hard-to-reach and 'hidden' subpopulations is crucial to containing the HIV epidemic in low prevalence settings and in slowing the rate of transmission in high prevalence settings. For a variety of reasons, however, conventional facility and survey-based surveillance data collection strategies are ineffective for a number of key subpopulations, particularly those whose b...