641 research outputs found

    Scales in Trimerorhachis

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    17 p. : ill. ; 24 cm.Includes bibliographical references (p. 16-17)

    Li+ intercalation in isostructural Li2VO3 and Li2VO2 with O2- and mixed O2-/F- anions

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    Mixed-anion materials for Li-ion batteries have been attracting attention in view of their tunable electrochemical properties. Herein, we compare two isostructural (Fm3m) model intercalation materials Li2VO3 and Li2VO2F with O2- and mixed O2-/F- anions, respectively. Synchrotron X-ray diffraction and pair distribution function data confirm large structural similarity over long-range and at the atomic scale for these materials. However, they show distinct electrochemical properties and kinetic behaviour arising from the different anion environments and the consequent difference in cationic electrostatic repulsion. In comparison with Li2VO3 with an active V4+/5+ redox reaction, the material Li2VO2F with oxofluoro anions and the partial activity of V3+/5+ redox reaction favor higher theoretical capacity (460 mA h g-1vs. 230 mA h g-1), higher voltage (2.5 V vs. 2.2 V), lower polarization (0.1 V vs. 0.3 V) and faster Li+ chemical diffusion (~10-9 cm2 s-1vs. ~10-11 cm2 s-1). This work not only provides insights into the understanding of anion chemistry, but also suggests the rational design of new mixed-anion battery materials

    Toward Near‐Field Tsunami Forecasting Along the Cascadia Subduction Zone Using Rapid GNSS Source Models

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    Over the past 15 years and through multiple large and devastating earthquakes, tsunami warning systems have grown considerably in their efficacy in providing timely and accurate forecasts to affected communities. However, one part of tsunami warning that still needs improvement is forecasts catered to local, near‐field communities in the time after an earthquake rupture but before coastal inundation. In this study, we test a rapid, Global Navigation Satellite Systems (GNSS)‐driven earthquake characterization model using a large data set of synthetic megathrust ruptures for its near‐field tsunami forecasting potential. We also provide a framework for tsunami forecasting that focuses on the likelihood of exceedance of user‐defined coastal amplitudes that may be of use in the first 15 min following an earthquake. Specifically, we can estimate the earthquake magnitude, without saturation, for 82% of tested ruptures. We can also identify test ruptures as dominantly thrust events, without analyst guidance for 92% of tested thrust ruptures. Finally, modeling the tsunami component of our rapidly estimated fault rupture leads to greater than 80% accuracy in identifying tsunami impact at key coastal amplitude thresholds. This is promising for near‐field warning when the time prior to inundation is limited to tens of minutes. We focus this study on large megathrust ruptures along the quiescent Cascadia subduction zone where there is already a dense GNSS network

    A process evaluation of user fees abolition for pregnant women and children under five years in two districts in Niger (West Africa)

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    <p>Abstract</p> <p>Background</p> <p>African policy-makers are increasingly considering abolishing user fees as a solution to improve access to health care systems. There is little evidence on this subject in West Africa, and particularly in countries that have organized their healthcare system on the basis of the Bamako Initiative. This article presents a process evaluation of an NGO intervention to abolish user fees in Niger for children under five years and pregnant women.</p> <p>Methods</p> <p>The intervention was launched in 2006 in two health districts and 43 health centres. The intervention consisted of abolishing user fees and improving the quality of services (drugs, ambulance, etc.). We carried out a process evaluation in April 2007 using qualitative and quantitative data. Three data collection methods were used: i) individual in-depth interviews (n = 85) and focus groups (n = 8); ii) participant observation in 12 health centres; and iii) self-administered structured questionnaires (n = 51 health staff).</p> <p>Results</p> <p>The population favoured abolition; health officials and local decision-makers were in favour, but they worried about its sustainability. Among health workers, opposition to providing free services was more widespread. The strengths of the process were: a top-down phase of information and raising community awareness; appropriate incentive measures; a good drug supply system; and the organization of a medical evacuation system. The major weaknesses of the process were: the perverse effects of incentive bonuses; the lack of community-based management committees' involvement in the management; the creation of a system running in parallel with the BI system; the lack of action to support the service offer; and the poor coordination of the availability of free services at different levels of the health pyramid. Some unintended outcomes are also documented.</p> <p>Conclusion</p> <p>The linkages between systems in which some patients pay (Bamako Initiative) and some do not should be carefully considered and organized in accordance with the local reality. For the poorest patients to really benefit, it is essential that, at the same time, the quality of services be improved and mechanisms be put in place to prevent abuses. Much remains to be done to generate knowledge on the processes for abolishing fees in West Africa.</p

    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

    Validation of the Brief Developmental Assessment in pre-school children with heart disease

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    INTRODUCTION: The objective of this study was to prospectively validate the “Brief Developmental Assessment”, which is a new early recognition tool for neurodevelopmental abnormalities in children with heart disease that was developed for use by cardiac teams. METHODS: This was a prospective validation study among a representative sample of 960 pre-school children with heart disease from three United Kingdom tertiary cardiac centres who were analysed grouped into five separate age bands. RESULTS: The “Brief Developmental Assessment” was successfully validated in the older four age bands, but not in the youngest representing infants under the age of 4 months, as pre-set validation thresholds were met – lower 95% confidence limit for the correlation coefficient above 0.75 – in terms of agreement of scores between two raters and with an external measure the “Mullen Scales of Early Learning”. On the basis of American Association of Pediatrics Guidelines, which state that the sensitivity and specificity of a developmental screening tool should fall between 70 and 80%, “Brief Developmental Assessment” outcome of Red meets this threshold for detection of Mullen scores >2 standard deviations below the mean. CONCLUSION: The “Brief Developmental Assessment” may be used to improve the quality of assessment of children with heart disease. This will require a training package for users and a guide to action for abnormal results. Further research is needed to determine how best to deploy the “Brief Developmental Assessment” at different time points in children with heart disease and to determine the management strategy in infants younger than 4 months old

    Cost and impact of policies to remove and reduce fees for obstetric care in Benin, Burkina Faso, Mali and Morocco.

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    BACKGROUND: Across the Africa region and beyond, the last decade has seen many countries introducing policies aimed at reducing financial barriers to obstetric care. This article provides evidence of the cost and effects of national policies focussed on improving financial access to caesarean and facility deliveries in Benin, Burkina Faso, Mali and Morocco. METHODS: The study uses a comparative case study design with mixed methods, including realist evaluation components. This article presents results across 14 different data collection tools, used in 4-6 research sites in each of the four study countries over 2011-13. The methods included: document review; interviews with key informants; analysis of secondary data; structured extraction from medical files; cross-sectional surveys of patients and staff; interviews with patients and observation of care processes. RESULTS: The article finds that the policies have contributed to continued increases in skilled birth attendance and caesarean sections and a narrowing of inequalities in all four countries, but these trends were already occurring so a shift cannot be attributed solely to the policies. It finds a significant reduction in financial burdens on households after the policy, suggesting that the financial protection objectives may have been met, at least in the short term, although none achieved total exemption of targeted costs. Policies are domestically financed and are potentially sustainable and efficient, and were relatively thoroughly implemented. Further, we find no evidence of negative effects on technical quality of care, or of unintended negative effects on untargeted services. CONCLUSIONS: We conclude that the policies were effective in meeting financial protection goals and probably health and equity goals, at sustainable cost, but that a range of measures could increase their effectiveness and equity. These include broadening the exempted package (especially for those countries which focused on caesarean sections alone), better calibrated payments, clearer information on policies, better stewardship of the local health system to deal with underlying systemic weaknesses, more robust implementation of exemptions for indigents, and paying more attention to quality of care, especially for newborns

    Relationships between spruce budworm damage and site factors in spruce-fir-dominated ecosystems of Western Upper Michigan

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    Damage by the spruce budworm, Choristoneura fumiferana (Clemens), on balsam fir, Abies balsamea (L.) Mill., in local ecosystems (site units) of the Ottawa National Forest (western Upper Peninsula of Michigan, U.S.A.) was studied in relation to site factors. A multi-factor ecological approach was used to distinguish 25 spruce-fir-dominated ecosystems on a variety of different sites, ranging from dry-mesic outwash plains to river floodplains and swamps. Spruce budworm damage on balsam fir appears to be more directly related to site factors (specifically soil type and drainage class) than to stand parameters such as relative dominance or living-plus-dead basal area. Damage on balsam fir was greatest on wetland ecosystems with organic soils and on dryland ecosystems with impeded drainage. The heavy damage on these soils is probably a consequence of shallow rooting habit which predisposes the physiologically mature balsam fir to drought injury, lessened vigor, and a lessened ability to withstand defoliation. Black spruce, Picea mariana (Mill.) B.S.P., also exhibited heavy damage on sites where it is not well adapted, i.e. somewhat excessively drained dryland ecosystems. An understanding of the site factors and the ecosystem classification provide the basis for predicting where the greatest damage can be expected.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26584/1/0000125.pd
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