969 research outputs found

    Sea state and rain: a second take on dual-frequency altimetry

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    TOPEX and Jason were the first two dual-frequency altimeters in space, with both operating at Ku- and C-band. Each thus gives two measurements of the normalized backscatter, sigma0, (from which wind speed is calculated) and two estimates of wave height. Departures from a well-defined relationship between the Ku- and C-band sigma0 values give an indication of rain.This paper investigates differences between the two instruments using data from Jason's verification phase. Jason's Ku-band estimates of wave height are ~1.8% less than TOPEX's, whereas its sigma0 values are higher. When these effects have been removed the root mean square (r.m.s.) mismatch between TOPEX and Jason's Ku-band observations is close to that for TOPEX's observations at its two frequencies, and the changes in sigma0 with varying wave height conditions are the same for the two altimeters. Rain flagging and quantitative estimates of rain rate are both based on the atmospheric attenuation derived from the sigma0 measurements at the two frequencies. The attenuation estimates of TOPEX and Jason agree very well, and a threshold of -0.5 dB is effective at removing the majority of spurious data records from the Jason GDRs. In the high sigma0 regime, anomalous data can be cause by processes other than rain. Consequently, for these low wind conditions, neither can reliable rain detection be based on altimetry alone, nor can a generic rain flag be expected to remove all suspect data

    Providing free maternal health care: ten lessons from an evaluation of the national delivery exemption policy in Ghana

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    Background: There is a growing movement, globally and in the Africa region, to reduce financial barriers to health care generally, but with particular emphasis on high priority services and vulnerable groups. Objective: This article reports on the experience of implementing a national policy to exempt women from paying for delivery care in public, mission and private health facilities in Ghana. Design: Using data from a complex evaluation which was carried out in 2005-2006, lessons are drawn which can inform other countries starting or planning to implement similar service-based exemption policies. Results: On the positive side, the experience of Ghana suggests that delivery exemptions can be effective and cost-effective, and that despite being universal in application, they can benefit the poor. However, certain ‘negative’ lessons are also drawn from the Ghana case study, particularly on the need for adequate funding, and for strong institutional ownership. It is also important to monitor the financial transfers which reach households, to ensure that providers are passing on benefits in full, while being adequately reimbursed themselves for their loss of revenue. Careful consideration should also be given to staff motivation and the role of different providers, as well as quality of care constraints, when designing the exemptions policy. All of this should be supported by a proactive approach to monitoring and evaluation. Conclusion: The recent movement towards making delivery care free to all women is a bold and timely action which is supported by evidence from within and beyond Ghana. However, the potential for this to translate into reduced mortality for mothers and babies fundamentally depends on the effectiveness of its implementation

    Large scale analysis of expressed genes in common wheat

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    To assess associations between occlusal tooth wear and shortened dental arches (SDA) in Chinese 40 years and older subjects. From a sample of 1462 urban and rural adults, those presenting with SDA (n = 150) were compared with a control group of 65 randomly selected subjects with complete dentitions (CDA). Occlusal wear was assessed using a modified Smith and Knight index - the occlusal tooth wear index (OWTI) - and analysed using multivariate (logistic) regression. There was no significant effect from SDA on severe occlusal wear (OTWI score 3 or 4: OR = 2.016; 95% CI = 0.960-4.231; P = 0.064). Higher age was associated with severe occlusal wear (P values </=0.007) and with higher mean OTWI scores; urban had less often severe occlusal wear than rural residents (OR = 0.519; P = 0.008). Higher mean OTWI scores were associated with rural residents, except for anterior teeth. Females had lower mean OTWI score for anterior teeth (effect = -0.153; P = 0.030). Premolars in SDA had higher mean OTWI scores compared with those in CDA (effect = +0.213; P = 0.006). In SDA, more posterior occluding pairs (POPs) were associated with lower mean OTWI sores for anterior teeth (effect: -0.158; P = 0.008) and higher scores for molars (effect: +0.249, P = 0.003). Subjects with SDA or CDA presented comparable occlusal wear, but premolars in SDA tend to have higher probability for having occlusal wear. Fewer numbers of POPs were associated with more wear in anterior teeth

    Dental Status and Associated Factors in a Dentate Adult Population in Bulgaria: A Cross-Sectional Survey

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    This study aimed to determine variations in the dental status of a dentate adult population in terms of “decayed,” “missing,” and “filled” teeth in relation to several sociodemographic and behavioral factors. Quota sampling was used to draw 2531 subjects aged 20 years and over. Data were collected by means of a questionnaire and an oral examination. Multiple logistic regression analyses were performed to observe associations between “decayed,” “missing,” and “filled” teeth and the factors of interest. The mean numbers of “decayed,” “missing,” and “filled” teeth were 2.2, 6.7, and 4.9, respectively. Molar teeth were significantly more often “missing” than premolar and anterior teeth. Age, gender, education, and tooth brushing revealed most noticeable associations. Increasing age was associated with a lower chance of having “decayed” and “filled” teeth, but with a higher chance of having “missing” teeth. Females were more likely to have “missing” and “filled” teeth. Higher education was associated with a lower chance of having “missing” teeth. More frequent tooth brushing was associated with a lower chance of having “decayed” and “missing” teeth, but with a higher chance of having “filled” teeth. These risk indicators should be considered in prevention program planning if reduction of tooth loss is to be achieved

    Dental Laboratory Production of Prosthetic Restorations in a Population in Sofia, Bulgaria: A Descriptive Study

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    Objective. To describe prosthodontic production related to mutilated dentitions in Sofia, Bulgaria. Methods. Prosthodontic production from 5 dental laboratories was recorded during a 14-day period. Production was related to dentitions as noted from casts. Dentitions were classified as edentulous, interrupted/reduced, slightly interrupted, shortened, and complete. The representativeness of the laboratory sample was verified trough comparison with a Sofia population sample using proportions of crowned or replaced teeth per dental region. Results. The total production consisted of 243 crowns, 16 post and cores, 82 fixed dental prostheses, and 41 removable dentures. Proportions of crowned teeth were significantly different between the samples; proportions of replaced teeth were not. Of the 58 incomplete dentitions analyzed, 19 were restored to the level of completeness, 15 resulted in slightly interrupted, and 24 in shortened dentitions. Conclusions. Predominantly fixed restorations were provided to restore mutilated dentitions to a functional level and not necessarily to complete dentitions

    Simplified antiviral prophylaxis with or and without artificial feeding to reduce mother-to-child transmission of HIV in low and middle income countries: modelling positive and negative impact on child survival.

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    BACKGROUND: Antiviral prophylaxis is recommended for HIV positive mothers to prevent mother-to-child transmission of HIV. To date UNAIDS and WHO policy has been based on a study in Thailand which showed a reduction in transmission by half with short course AZT (Zidovudine) treatment together with artificial feeding. We modelled the possible positive and negative effects on child deaths in low and middle resource developing country settings of two interventions to reduce mother to child transmission (MTCT) of HIV: antenatal testing, short-course antivirals (zidovudine or nevirapine), firstly with and then without artificial feeding. MATERIAL AND METHODS: Estimates are made of child lives likely to be saved by the programme by age ten years, balanced against increases in deaths due to more uninfected mothers choosing to use artificial feeds where these are part of the intervention. Mid-point values for variables affecting the balance of mortality gains and losses are taken from recent published data for low and middle income developing countries and a sensitivity analysis is undertaken. RESULTS: In low income settings the use of antivirals alone would result in an estimated gain in child survival of around 0.36%, representing 360 deaths avoided from a birth cohort of 100,000 by age 10 years. Adding artificial feeding could reduce the gain to 0.03% (30 deaths avoided). In middle income settings the gain from antivirals alone would be 0.26% but as 'spill-over' of artificial feeding to uninfected women was more likely it could result in a net increase of child deaths of up to 1.08% (1,080 additional deaths). A sensitivity analysis emphasised this potential for regimens using artificial feeding if progamme participation was low, and under most circumstances in middle income settings. CONCLUSIONS: HIV testing and use of antivirals by infected mothers, if well implemented, will be effective at a population level in reducing MTCT. However the addition of artificial feeding is potentially be a high risk strategy, especially in middle income countries.sch_iih7pub2814pub

    Occlusion and Temporomandibular Function among Subjects with Mandibular Distal Extension Removable Partial Dentures

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    Objective. To quantify effects on occlusion and temporomandibular function of mandibular distal extension removable partial dentures in shortened dental arches. Methods. Subjects wearing mandibular extension removable partial dentures (n = 25) were compared with subjects with shortened dental arches without extension (n = 74) and with subjects who had worn a mandibular extension removable partial denture in the past (n = 19). Subjects with complete dentitions (n = 72) were controls. Data were collected at baseline and at 3-, 6-, and 9-year observations. Results. Occlusal activity in terms of reported awareness of bruxism and occlusal tooth wear of lower anterior teeth did not differ significantly between the groups. In contrast, occlusal tooth wear of premolars in shortened dental arches with or without extension dentures was significantly higher than in the controls. Differences amongst groups with respect to signs and symptoms related to temporomandibular disorders were not found. Occlusal support of the dentures did not influence anterior spatial relationship. Occlusal contacts of the denture teeth decreased from 70% for second premolars via 50% for first molars, to 30% for second molars. Conclusions. Mandibular distal extension removable partial dentures in moderate shortened dental arches had no effects on occlusion and temporomandibular function

    Incorporating comorbidity within risk adjustment for UK pediatric cardiac surgery

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    INTRODUCTION: When considering early survival rates after pediatric cardiac surgery it is essential to adjust for risk linked to case complexity. An important but previously less well understood component of case mix complexity is comorbidity. METHODS: National congenital heart diseases audit (NCHDA) data representing all pediatric cardiac surgery procedures undertaken in the United Kingdom and Ireland between 2009 and 2014 was used to develop and test groupings for comorbidity and additional non procedure based risk factors within a risk adjustment model for 30-day mortality. A mixture of expert consensus based opinion and empiric statistical analyses were used to define and test the new comorbidity groups. RESULTS: The study dataset consisted of 21,838 pediatric cardiac surgical procedure episodes in 18,834 patients with 539 deaths (raw 30-day mortality rate 2.5%). In addition to surgical procedure type, primary cardiac diagnosis, univentricular status, age, weight, procedure type (bypass, non-bypass or hybrid) and era, the new risk factor groups of: non Downs congenital anomalies, acquired comorbidities, increased severity of illness indicators (such as pre-operative mechanical ventilation or circulatory support) and additional cardiac risk factors (such as heart muscle conditions and raised pulmonary arterial pressure) all independently increased the risk of operative mortality. DISCUSSION: In an era of low mortality rates across a wide range of operations, non-procedure based risk factors form a vital element of risk adjustment and their presence leads to wide variations in the predicted risk of a given operation
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