999 resultados para Rural transit


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Photometric transit surveys promise to complement the currently known sample of extra-solar planets (ESPs) by providing additional information on the planets and especially their radii. Here, we present ESP candidates from one such survey called, the Wide Angle Search for Planets (WASP) obtained with the SuperWASP wide-field imaging system. Observations were taken with SuperWASP North located in La Palma during the 2004 April to October observing season. The data cover fields between 23 and 03 h in RA at declinations above +12. This amounts to over ~400000 stars with V magnitudes 8-13.5. For the stars brighter than 12.5, we achieve better than 1 per cent photometric precision. Here, we present 41 sources with low-amplitude variability between ~1 and 10 mmag, from which we select 12 with periods between 1.2 and 4.4 d as the most promising ESP candidates. We discuss the properties of these ESP candidates, the expected fraction of transits recovered for our sample and implications for the frequency and detection of hot-Jupiters.

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We present a fast and efficient hybrid algorithm for selecting exoplanetary candidates from wide-field transit surveys. Our method is based on the widely used SysRem and Box Least-Squares (BLS) algorithms. Patterns of systematic error that are common to all stars on the frame are mapped and eliminated using the SysRem algorithm. The remaining systematic errors caused by spatially localized flat-fielding and other errors are quantified using a boxcar-smoothing method. We show that the dimensions of the search-parameter space can be reduced greatly by carrying out an initial BLS search on a coarse grid of reduced dimensions, followed by Newton-Raphson refinement of the transit parameters in the vicinity of the most significant solutions. We illustrate the method's operation by applying it to data from one field of the SuperWASP survey, comprising 2300 observations of 7840 stars brighter than V = 13.0. We identify 11 likely transit candidates. We reject stars that exhibit significant ellipsoidal variations caused indicative of a stellar-mass companion. We use colours and proper motions from the Two Micron All Sky Survey and USNO-B1.0 surveys to estimate the stellar parameters and the companion radius. We find that two stars showing unambiguous transit signals pass all these tests, and so qualify for detailed high-resolution spectroscopic follow-up.

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I challenge the popular notion of European rural development group dynamics and argue for a better understanding of the role of micro-politics as a means of enhancing the performance of these groups. The views are research based and have relevance to the broader rural development and regeneration sector. Micro-politics involves knowledge, power, trust, perceptions, understanding, social networks, values and traits that arise as a result of individuals interacting within a group whilst working on a shared goal, such as rural development. The monetary and time costs to a community of failing to address micro-politics and nurture positive group relations are considerable. These include time spent in unproductive meetings and poorly prioritized—and ultimately unsuccessful—funding applications as a result of failure to agree priorities. Successful groups rely on individuals interacting in a way that achieves a greater social good. Mutual trust amongst the actors lies at the heart of effective group activity. Effective management of micro-politics requires steps to nurture a culture of mutual trust to ensure that rural development actors co-operate rather than play destructive games with one another. A case study example of a relatively straightforward approach illustrates how this might be done in practice.

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PURPOSE. To assess the prevalence of age-related macular degeneration (AMD) in a rural population in Northern India. METHODS. In a pilot feasibility study, 1443 people (median age, 60 years; 52% women), were identified from enumeration of the 50+ age group in 11 randomly sampled villages from a rural, periurban district of Haryana, Northern India. Of those identified, 87% attended an eye examination that included digital fundus photography. Fundus images were graded at a single reading center using definitions from the Wisconsin Age-Related Maculopathy Grading System. RESULTS. Fundus photographs were available for 1101 participants. Overall, 28.8% of participants had ungradable fundus images due to cataract. Including all with ungradable images in the denominator, the prevalence of soft drusen was 34.0% (95% confidence interval [CI] 26.1–42.9); of soft indistinct drusen, 2.2% (95% CI, 1.1–4.4); and of pigmentary irregularities, 10.8% (95% CI, 7.1–16.1). There were 15 (1.4%) cases of late-stage AMD (95% CI, 0.8–2.3) with the prevalence rising from 0.4% in the 50- to 59-year age range to 4.6% in those aged 70 years or older. CONCLUSIONS. Drusen and pigmentary irregularities are common among the rural northern Indian population. The prevalence of late AMD is similar to that encountered in Western settings and is likely to contribute significantly to the burden of vision loss in older people in the developing world.