3,526 research outputs found

    Children's Savings Accounts: Why Design Matters

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    Estimates how specific features of CSAs -- supplemental grants, federal matches, private contributions, and nontaxability -- would affect the impact of CSAs on wealth distribution. Analyzes data by mother's race/ethnicity, income, and education

    Advantages of 3D time-of-flight range imaging cameras in machine vision applications

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    Machine vision using image processing of traditional intensity images is in wide spread use. In many situations environmental conditions or object colours or shades cannot be controlled, leading to difficulties in correctly processing the images and requiring complicated processing algorithms. Many of these complications can be avoided by using range image data, instead of intensity data. This is because range image data represents the physical properties of object location and shape, practically independently of object colour or shading. The advantages of range image processing are presented, along with three example applications that show how robust machine vision results can be obtained with relatively simple range image processing in real-time applications

    Demographic characteristics and association of serum Vitamin B12, ferritin and thyroid function with premature canities in Indian patients from an urban skin clinic of North India: A retrospective analysis of 71 cases

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    yesBackground: The incidence of self-reported premature hair graying (PHG) seems to be on the rise. PHG has a profound impact on the patient's quality of life. It remains an incompletely understood etiology with limited and modest treatment options. Aim: The evaluation of the demographic and clinical profile of patients with premature canities, and exploration of the association of this entity with certain systemic disorders suspected to be related to its etiology. Methods: Seventy-one cases of premature canities (onset noticed by patients before 25 years of age) presenting to an urban skin clinic in Gurugram, India, between September 2012 and September 2015 with this complaint were retrospectively analyzed. The patient records were retrieved that provided details of the onset, duration and pattern of involvement, history, and examination findings (scalp, cutis, and general physical). Since all these patients had been screened for anemia, thyroid disorder, fasting blood glucose, and Vitamin B12 levels at the time of presentation, these parameters were also available for analysis. Results: The mean age at onset of graying was 10.2 ± 3.6 years (range: 5–19 years), with an almost equal gender distribution. The earliest age of onset recorded was 5 years. A positive family history of PHG (at least one of the biological parents or siblings) was obtained in 64 (90.1%) of the cases. The temporal regions of the scalp (35.2%) were most commonly involved followed by the frontal region (18.3%). Hypovitaminosis B12 and hypothyroidism showed significant association with the disorder, whereas anemia, serum ferritin, and fasting blood glucose did not. Conclusion: The age of onset of hair graying can be as low as 5 years. Temporal and frontal areas are the most commonly involved sites. A strong family history, Vitamin B12 deficiency, and hypothyroidism are strongly associated with PHG. Larger case–control studies are mandated for discerning the correlation of these and other risk factors with PHG

    Hair Pigmentation: A Research Update

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    Hair is a uniquely mammalian trait with important functions, most easily appreciated in furred mammals. Our skin and hair color contribute very significantly to our overall visual appearance by highlighting striking variations between human sub-groups. Although melanins, hemoglobins, and carotenoids define the color perceived at the skin surface, our hair color relies only on the presence or absence of different melanins. The hair shaft's physical aspects provide only minor color modification. Various selective evolutionary pressures have determined that within the context of our specific ethnic backgrounds a bewildering array of natural shades are seen; ranging from yellows, reds, and browns to black and that harbinger of lost youth, gray/white hair. Skin/hair follicle melanins are formed in cytoplasmic organelles called melano-somes produced by neural crest-derived pigment cells called melano-cytes and are the product of a complex, phylogenetically ancient, biochemical pathway called melano-genesis. The following provides a review of research presented at the 4th Intercontinental Meeting of Hair Research Societies 2004 and so is not intended to represent a fully comprehensive overview of the subject—for that readers are directed to key references

    Budget constraint and vaccine dosing: A mathematical modelling exercise

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    BACKGROUND: Increasing the number of vaccine doses may potentially improve overall efficacy. Decision-makers need information about choosing the most efficient dose schedule to maximise the total health gain of a population when operating under a constrained budget. The objective of this study is to identify the most efficient vaccine dosing schedule within a fixed vaccination budget from a healthcare payer perspective. METHODS: An optimisation model is developed in which maximizing the disease reduction is the functional objective and the constraint is the vaccination budget. The model allows variation in vaccination dosing numbers, in cost difference per dose, in vaccine coverage rate, and in vaccine efficacy. We apply the model using the monovalent rotavirus vaccine as an example. RESULTS: With a fixed budget, a 2-dose schedule for vaccination against rotavirus infection with the monovalent vaccine results in a larger reduction in disease episodes than a 3-dose scheme with the same vaccine under most circumstances. A 3-dose schedule would only be better under certain conditions: a cost reduction of >26% per dose, combined with vaccine efficacy improvement of ≥5% and a target coverage rate of 75%. Substantial interaction is observed between cost reduction per dose, vaccine coverage rate, and increased vaccine efficacy. Sensitivity analysis shows that the conditions required for a 3-dose strategy to be better than a 2-dose strategy may seldom occur when the budget is fixed. The model does not consider vaccine herd effect, precise timing for additional doses, or the effect of natural immunity development. CONCLUSIONS: Under budget constraint, optimisation modelling is a helpful tool for a decision-maker selecting the most efficient vaccination dosing schedule. The low dosing scheme could be the optimal option to consider under the many scenarios tested. The model can be applied under many different circumstances of changing dosing schemes with single or multiple vaccines

    A Qualitative Study of Doctoral Student Supervisory Development

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    Doctoral students in a Council for Accreditation of Counseling and Related Educational Programs (CACREP) accredited program are required to have training in clinical supervision. Frequently doctoral counseling programs have a supervision practicum course designed to facilitate student development into a supervisor. This qualitative research utilized a collective case study approach to gather descriptions of the experiences doctoral students found most useful about their supervision training. Doctoral students enrolled in a supervision practicum course were asked to describe their experiences as supervisors in training through a semi-structured interview approach. Three broad themes emerged from the data: Facilitation of Development, Formation of Supervisory Style, and Supervisory Roles. Descriptions of the themes and specific experiences doctoral students identified as contributing to their development are explored

    Export Tourism Input-Output Multipliers for Ireland. Quarterly Economic Commentary Special Article, May 1982

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    This paper focuses on some difficulties involved in the interpretation of earlier studies and goes on to calculate upper bound estimates of some of the principal economic effects of Irish export tourism in 1976. The 1976 input-output data of Henry (1980) form the basis for the calculations herein

    Does error control suppress spuriosity?

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    In the numerical solution of initial value ordinary differential equations, to what extent does local error control confer global properties? This work concentrates on global steady states or fixed points. It is shown that, for systems of equations, spurious fixed points generally cease to exist when local error control is used. For scalar problems, on the other hand, locally adaptive algorithms generally avoid spurious fixed points by an indirect method---the stepsize selection process causes spurious fixed points to be unstable. However, problem classes exist where, for arbitrarily small tolerances, stable spurious fixed points persist with significant basins of attraction. A technique is derived for generating such examples

    Tattoo ink nanoparticles in skin tissue and fibroblasts

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    YesTattooing has long been practised in various societies all around the world and is becoming increasingly common and widespread in the West. Tattoo ink suspensions unquestionably contain pigments composed of nanoparticles, i.e., particles of sub-100 nm dimensions. It is widely acknowledged that nanoparticles have higher levels of chemical activity than their larger particle equivalents. However, assessment of the toxicity of tattoo inks has been the subject of little research and ink manufacturers are not obliged to disclose the exact composition of their products. This study examines tattoo ink particles in two fundamental skin components at the nanometre level. We use atomic force microscopy and light microscopy to examine cryosections of tattooed skin, exploring the collagen fibril networks in the dermis that contain ink nanoparticles. Further, we culture fibroblasts in diluted tattoo ink to explore both the immediate impact of ink pigment on cell viability and also to observe the interaction between particles and the cells
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