2,514 research outputs found

    The Science Studio – A Workshop Approach to Introductory Physical Science

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    This paper describes the Science Studio, an innovative workshop approach for instruction in a physical science course that combines aspects of traditional lecture and laboratory. The target audience for this introductory course is non-science majors, including prospective teachers. An inquiry-based, technology-rich learning environment has been created to allow students hands-on, in-depth exploration of topics in physics, and earth and space science. Course philosophy, course development, and sample activities are described in this paper, along with outcomes from a project-wide evaluation of the Virginia Collaborative for Excellence in the Preparation of Teachers (VCEPT), an investigation of change in student attitudes and the lasting impact of the studio model at Norfolk State University

    Fast Separable Non-Local Means

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    We propose a simple and fast algorithm called PatchLift for computing distances between patches (contiguous block of samples) extracted from a given one-dimensional signal. PatchLift is based on the observation that the patch distances can be efficiently computed from a matrix that is derived from the one-dimensional signal using lifting; importantly, the number of operations required to compute the patch distances using this approach does not scale with the patch length. We next demonstrate how PatchLift can be used for patch-based denoising of images corrupted with Gaussian noise. In particular, we propose a separable formulation of the classical Non-Local Means (NLM) algorithm that can be implemented using PatchLift. We demonstrate that the PatchLift-based implementation of separable NLM is few orders faster than standard NLM, and is competitive with existing fast implementations of NLM. Moreover, its denoising performance is shown to be consistently superior to that of NLM and some of its variants, both in terms of PSNR/SSIM and visual quality

    Ghost doctors - absenteeism in Bangladeshi health facilities

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    The authors report on a study in which unannounced visits were made to health clinics in Bangladesh with the intention of discovering what fraction of medical professionals were present at their assigned post. This survey represents the first attempt to quantify the extent of the problem on a nationally representative scale. Nationwide the average number of vacancies over all types of providers in rural health centers is 26 percent. Regionally, vacancy rates (unfilled posts) are generally higher in the poorer parts of the country. Absentee rates at over 40 percent are particularly high for doctors. When separated into level of facility, the absentee rate for doctors at the larger clinics is 40 percent, but at the smaller sub-centers with a single doctor, the rate is 74 percent. Even though the primary purpose of this survey is to document the extent of the problem among medical staff, the authors also explore the determinants of staff absenteeism. Whether the medical provider lives near the health facility, access to a road, and rural electrification are important determinants of the rate and pattern of staff absentee rates.Public Health Promotion,Gender and Health,Health Systems Development&Reform,Health Monitoring&Evaluation,Housing&Human Habitats,Health Systems Development&Reform,Health Monitoring&Evaluation,Housing&Human Habitats,Gender and Health,Agricultural Knowledge&Information Systems

    A Continuous Non-demolition Measurement of the Cs Clock Transition Pseudo-spin

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    We demonstrate a weak continuous measurement of the pseudo-spin associated with the clock transition in a sample of Cs atoms. Our scheme uses an optical probe tuned near the D1 transition to measure the sample birefringence, which depends on the z-component of the collective pseudospin. At certain probe frequencies the differential light shift of the clock states vanishes and the measurement is non-perturbing. In dense samples the measurement can be used to squeeze the collective clock pseudo-spin, and has potential to improve the performance of atomic clocks and interferometers.Comment: 4 pages, 4 figures, ReVTeX, modified text in response to referee's comment
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