556 research outputs found
Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment
No full textIn International Union for Conservation of Nature (IUCN) Red List assessments, extent of occurrence (EOO) is a key measure of extinction risk. However, the way assessors estimate EOO from maps of species’ distributions is inconsistent among assessments of different species and among major taxonomic groups. Assessors often estimate EOO from the area of mapped distribution, but these maps often exclude areas that are not habitat in idiosyncratic ways and are not created at the same spatial resolutions. We assessed the impact on extinction risk categories of applying different methods (minimum convex polygon, alpha hull) for estimating EOO for 21,763 species of mammals, birds, and amphibians. Overall, the percentage of threatened species requiring down listing to a lower category of threat (taking into account other Red List criteria under which they qualified) spanned 11–13% for all species combined (14–15% for mammals, 7–8% for birds, and 12–15% for amphibians). These down listings resulted from larger estimates of EOO and depended on the EOO calculation method. Using birds as an example, we found that 14% of threatened and near threatened species could require down listing based on the minimum convex polygon (MCP) approach, an approach that is now recommended by IUCN. Other metrics (such as alpha hull) had marginally smaller impacts. Our results suggest that uniformly applying the MCP approach may lead to a one-time down listing of hundreds of species but ultimately ensure consistency across assessments and realign the calculation of EOO with the theoretical basis on which the metric was founded
A quantum moat barrier, realized with a finite square well
No full textThe notion of a double well potential typically involves two regions of space separated by a repulsive potential barrier. The ground state
is a wave function that is suppressed in the barrier region and localized in the two surrounding regions. We illustrate that an attractive potential well (a quantum moat) with a finite non-zero width also acts as a barrier, using a simple square well model. We also show how the pseudopotential method both explains the role of the well as a barrier, and greatly improves the efficiency of constructing wave functions for this system using matrix diagonalization. With this simplified model we provide an introduction to the ideas typically used to simplify calculations in solids, where in place of the double well potential, multiple potentials occur in a periodic array.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Newly-discovered ring-moat dome structures in the lunar maria : possible origins and implications
No full textWe report on a newly discovered morphological feature on the lunar surface, here named Ring-Moat Dome Structure (RMDS). These low domes (a few meters to ~20 m height with slopes <5°) are typically surrounded by narrow annular depressions or moats. We mapped about 2,600 RMDSs in the lunar maria with diameters ranging from tens to hundreds of meters. Four candidate hypotheses for their origin involving volcanism are considered. We currently favor a mechanism for the formation of the RMDS related to modification of the initial lava flows through inflated flow squeeze-ups and/or extrusion of magmatic foams below a cooling lava flow surface. These newly discovered features provide new insights into the nature of emplacement of lunar lava flows, suggesting that in the waning stages of a dike emplacement event, magmatic foams can be produced, extrude to the surface as the dike closes, and break through the upper lava flow thermal boundary layer (crust) to form foam mounds and surrounding moats
Cost-utility of transcatheter aortic valve implantation for inoperable patients with severe aortic stenosis treated by medical management: a UK cost-utility analysis based on patient-level data from the ADVANCE study.
No full textOBJECTIVE: To use patient-level data from the ADVANCE study to evaluate the cost-effectiveness of transcatheter aortic valve implantation (TAVI) compared to medical management (MM) in patients with severe aortic stenosis from the perspective of the UK NHS.
METHODS: A published decision-analytic model was adapted to include information on TAVI from the ADVANCE study. Patient-level data informed the choice as well as the form of mathematical functions that were used to model all-cause mortality, health-related quality of life and hospitalisations. TAVI-related resource use protocols were based on the ADVANCE study. MM was modelled on publicly available information from the PARTNER-B study. The outcome measures were incremental cost-effectiveness ratios (ICERs) estimated at a range of time horizons with benefits expressed as quality-adjusted life-years (QALY). Extensive sensitivity/subgroup analyses were undertaken to explore the impact of uncertainty in key clinical areas.
RESULTS: Using a 5-year time horizon, the ICER for the comparison of all ADVANCE to all PARTNER-B patients was £13 943 per QALY gained. For the subset of ADVANCE patients classified as high risk (Logistic EuroSCORE >20%) the ICER was £17 718 per QALY gained). The ICER was below £30 000 per QALY gained in all sensitivity analyses relating to choice of MM data source and alternative modelling approaches for key parameters. When the time horizon was extended to 10 years, all ICERs generated in all analyses were below £20 000 per QALY gained.
CONCLUSION: TAVI is highly likely to be a cost-effective treatment for patients with severe aortic stenosis
Evidence briefs and deliberative dialogues: Perceptions and intentions to act on what was learnt [Comptes rendus de preuves et réunions délibératoires: Perceptions et intentions d'agir sur ce qui a été découvert]
No full textObjective: To develop and implement a method for the evaluation of evidence briefs and deliberative dialogues that could be applied to comparative studies of similar strategies used in the support of evidence-informed policy-making. Methods: Participants who read evidence briefs and attended deliberative dialogues in Burkina Faso, Cameroon, Ethiopia, Nigeria, Uganda and Zambia were surveyed before the start of the dialogues - to collect their views on pre-circulated evidence briefs - and at the end of the dialogues - to collect their views on the dialogues. The respondents' assessments of the briefs and dialogues and the respondents' intentions to act on what they had learned were then investigated in descriptive statistical analyses and regression models. Findings: Of the 530 individuals who read the evidence briefs and attended dialogues, 304 (57percent) and 303 (57percent) completed questionnaires about the briefs and dialogues, respectively. Respondents viewed the evidence briefs and deliberative dialogues - as well as each of their key features - very favourably, regardless of the country, issue or group involved. Overall, not concluding with recommendations and not aiming for a consensus were identified as the least helpful features of the briefs and dialogues, respectively. Respondents generally reported strong intentions to act on what they had learnt. Conclusion: Although some aspects of their design may need to be improved or, at least, explained and justified to policy-makers and stakeholders, evidence briefs and deliberative dialogues appear to be highly regarded and to lead to intentions to act.AJZEN I, 1991, ORGAN BEHAV HUM DEC, V50, P179, DOI 10.1016-0749-5978(91)90020-T; [Anonymous], 2004, LANCET, V364, P1911, DOI DOI 10.1016-50140-6736(04)17485-0; [Anonymous], 2008, LANCET, V372, P1855, DOI DOI 10.1016-S0140-6736(08)61789-4; [Anonymous], 2011, KNOWL TRANSL TOOLK B; [Anonymous], 2009, COMM NOT READ FRIEND; Boyko J., 2010, DELIBERATIVE DIALOGU; Boyko JA, 2011, HEALTH RES POLICY SY, V9, DOI 10.1186-1478-4505-9-29; Boyko JA, 2012, SOC SCI MED, V75, P1938, DOI 10.1016-j.socscimed.2012.06.016; Chatham House, 2013, CHATH HOUS RUL; Eccles MP, 2006, IMPLEMENT SCI, V1, DOI 10.1186-1748-5908-1-28; Corkum S, 2008, LANCET, V372, P1130; First Global Symposium on Health Systems Research, 2010, MONTR STAT STEER COM; Francis JJ, 2008, IMPLEMENT SCI, V3, DOI 10.1186-1748-5908-3-50; Francis JJ, 2004, CONSTRUCTING QUESTIO; Hamid M, 2005, LANCET, V366, P1758, DOI 10.1016-S0140-6736(05)67709-4; Innvaer Simon, 2002, J Health Serv Res Policy, V7, P239, DOI 10.1258-135581902320432778; Johnson NA, 2010, PROCEDURES MANUAL EV; Johnson NA, 2009, PROCEDURES MANUAL EV; Lavis J, 2007, INT DIALOGUE EVIDENC; Lavis John, 2005, J Health Serv Res Policy, V10 Suppl 1, P35, DOI 10.1258-1355819054308549; Lavis John N, 2009, Health Res Policy Syst, V7 Suppl 1, pS14, DOI 10.1186-1478-4505-7-S1-S14; Lavis JN, 2006, B WORLD HEALTH ORGAN, V84, P620, DOI 10.2471-BLT.06.030312; Lavis John N, 2009, Health Res Policy Syst, V7 Suppl 1, pS13, DOI 10.1186-1478-4505-7-S1-S13; Lavis JN, 2005, SYSTEMATIC REV FACTO; Lavis John N, 2010, Int J Technol Assess Health Care, V26, P229, DOI 10.1017-S0266462310000206; Lomas J, 2005, CONCEPTUALIZING COMB; McMaster University [Internet], 2013, KTPE OV EV KNOWL TRA; Mitton C, 2007, MILBANK Q, V85, P729; Oxman AD, 2009, HEALTH RES POLICY SY, V7, P1, DOI DOI 10.1186-1478-4505-7-S1-S1; Rosenbaum SE, 2011, B WORLD HEALTH ORGAN, V89, P54, DOI 10.2471-BLT.10.075481; WHO, 2004, WORLD REP KNOWL BETT23
Evidence-informed health policies in Eastern Mediterranean countries: Comparing views of policy makers and researchers
No full textThe objective of this paper is to conduct comparative analysis about the views and practices of policy makers and researchers on the use of health systems evidence in policy making in selected Eastern Mediterranean countries. We analysed data from two self-reported surveys, one targeted at policy makers and the other at researchers. Results show a wide gap between policy makers and researchers when comparing perceptions on factors influencing the policy-making process and use of evidence in health policy making. Findings highlight specific areas for undertaking knowledge translation activities and implementing interventions to narrow the gap between policy makers and researchers.Black N, 2001, BRIT MED J, V323, P275, DOI 10.1136-bmj.323.7307.275; Derrick GE, 2011, PLOS ONE, V6, P18521; El-Jardali F, 2012, IMPLEMENT SCI, V7, DOI 10.1186-1748-5908-7-2; El-Jardali F, 2011, HEALTH RES POLICY SY, V9, DOI 10.1186-1478-4505-9-39; El-Jardali F, 2010, HEALTH POLICY PLANN, V25, P15, DOI 10.1093-heapol-czp059; El-Jardali F, 2012, BMC HEALTH SERV RES, V12, DOI 10.1186-1472-6963-12-200; Fowler F. J., 1995, IMPROVING SURVEY QUE; Gilson L e, 2012, HLTH POLICY SYSTEMS; Goldstein Judith, 1993, IDEAS FOREIGN POLICY; Guindon GE, 2010, CANADIAN MED ASS J, V182, P362; Hall PA, 1996, POLITICS MARKETS IND; Hanney SR, 2003, HEALTH RES POLICY SY, V1, P2, DOI DOI 10.1186-1478-4505-1-2; Haynes AS, 2012, PLOS ONE, V7, P32665; Hyder AA, 2010, HLTH POLICY PLAN, V26, P73; Innvaer Simon, 2002, J Health Serv Res Policy, V7, P239, DOI 10.1258-135581902320432778; Kendall J, 1999, WESTERN J NURS RES, V21, P743, DOI 10.1177-019394599902100603; Lavis John, 2005, J Health Serv Res Policy, V10 Suppl 1, P35, DOI 10.1258-1355819054308549; Lavis JN, 2002, MILBANK Q, V80, P125, DOI 10.1111-1468-0009.00005; Lavis JN, 2006, SUPPLY DISTRIBUTION, P1; Lavis JN, 2012, PLOS MED, V9; Lavis JN, 2006, B WORLD HEALTH ORGAN, V84, P620, DOI 10.2471-BLT.06.030312; Lavis JN, 2010, CANADIAN MED ASS J, V182, P350; Lavis JN, 2009, HLTH RES POLICY S S1, V7, P14; Lavis JN, 2009, HEALTH RES POLICY SY, V7, P13; Majdzadeh R, 2009, IRAN J PUBLIC HEALTH, V38, P58; Majdzadeh R, 2008, J CONTIN EDUC HEALTH, V28, P270, DOI 10.1002-chp.193; Moat K, 2011, SUPPORTING USE COCHR; Nedjat S, 2008, IMPLEMENT SCI, V3, DOI 10.1186-1748-5908-3-39; Oxman AD, 2009, HEALTH RES POLICY SY, V7, P1, DOI DOI 10.1186-1478-4505-7-S1-S1; Schieber G, 1998, HLTH REFORM MENA REG, V1; Tehran University of Medical Sciences Centre for Academic Health and Policy TUMS-KTE Study Group, SELF ASS TOOL DISC G; Trostle J, 1999, HEALTH POLICY PLANN, V14, P103, DOI 10.1093-heapol-14.2.103; Weatherford MS, 1995, STUD AM POLIT DEV, V9, P287; WHO, 2008, BAM CALL ACT RES HLT; WHO, 2011, ALL HLTH POL SYST RE; WHO EMRO, 2011, EMRC586 WHO EMRO; WHO EMRO (World Health Organization Eastern Mediterranean Regional Office), 2008, QAT PRIM HLTH CAR C; Wilczynski NL, 2004, CAN MED ASSOC J, V171, P1179, DOI 10.1503-cmaj.1040512; World Health Assembly, 2005, RES HLTH RES 2005; Yousefi-Nooraie R, 2009, J EVAL CLIN PRACT, V15, P1029, DOI 10.1111-j.1365-2753.2009.01184.x0
The British military occupation of the Cape 1795-1815 : the case of York Redoubt
No full textIncludes bibliographical references
THE DETERMINATION OF THE POLARIZABILITY TENSOR COMPONENTS OF THE WATER MOLECULE USING ITS ROTATIONAL RAMAN SPECTRUM
No full textAuthor Institution: Division of Chemistry, National Research Council of Canada,The principal components of the polarizability for moat common gases and vapors have been determined by Kerr effect measurements. However, experimental difficulties have precluded successful results in the case of water vapor. For asymmetric top molecules, there are two irreducible tensor components of the polarizability tensor which transform according to the totally symmetric representation. Both of these components ``connect” the same rotational states causing the rotational Raman line intensities to be dependent upon their relative sign and magnitude. Therefore, the contour of the rotational Raman spectrum, the depolarization ratio of the Rayleigh scattering, and the refractive index provide three independent experimental results which uniquely determine the three principal polarizability components. Using a computer program written to calculate Raman intensity contours for asymmetric tops, the calculated contour for water is found to be quite sensitive to the relative values of the two irreducible tensor components, and the observed spectrum has been accurately reproduced. The optimum tensor component ratio is combined with depolarization ratio results and the values of the mean polarizability known from refractive index measurements to derive the principal polarizability tensor components
Eutrophication of moderately deep Dutch lakes during the past century: flaws in the expectations of water management?
No full textWe studied the trophic development of the past 30-100 years in eight moderately deep Dutch lakes based on their sedimentary fossil diatom assemblages. The dominant diatoms indicating meso- to eutrophic conditions were Aulacoseira subarctica, Cyclotella ocellata, C. cyclopuncta, C. meneghiniana, Puncticulata bodanica, Aulacoseira granulata, Cyclostephanos dubius, C. invisitatus, Stephanodiscus hantzschii, S. medius, and S. parvus. Ordination of diatom data separated the lakes into four groups according to their total phosphorus concentrations (TP), water supply, water management, and origin. The first group consists of dike-breach lakes, which were in stable eutrophic to hypertrophic conditions throughout the past century with diatom-inferred TP (DI-TP) concentrations of between 70 and 300 μg l-1. The main factors influencing these dike-breach lakes are river management, ground water supply of riverine origin, and local land use. The second group are artificial lakes of fluctuating oligo- to mesotrophic conditions and DI-TP concentrations of 10-30 μg l-1. Only one of the artificial lakes showed a DI-TP increase due to changes in catchment agricultural practice. A third group includes an artificial moat and an inland dike-breach lake with DI-TP concentrations of 50-100 μg l-1. The fourth group contains an individual dike-breach lake with stable mesotrophic conditions of 50 μg l-1 throughout the past century. Rather than showing a regional pattern, the studied lakes behave very individualistically with regard to their trophic history, reflecting changes in the local hydrology and in their nutrient sources. © The Author(s) 2009
Green plants in the red : a baseline global assessment for the IUCN Sampled Red List Index for Plants
No full textPlants provide fundamental support systems for life on Earth and are the basis for all terrestrial ecosystems; a decline in plant diversity will be detrimental to all other groups of organisms including humans. Decline in plant diversity has been hard to quantify, due to the huge numbers of known and yet to be discovered species and the lack of an adequate baseline assessment of extinction risk against which to track changes. The biodiversity of many remote parts of the world remains poorly known, and the rate of new assessments of extinction risk for individual plant species approximates the rate at which new plant species are described. Thus the question 'How threatened are plants?' is still very difficult to answer accurately. While completing assessments for each species of plant remains a distant prospect, by assessing a randomly selected sample of species the Sampled Red List Index for Plants gives, for the first time, an accurate view of how threatened plants are across the world. It represents the first key phase of ongoing efforts to monitor the status of the world's plants. More than 20% of plant species assessed are threatened with extinction, and the habitat with the most threatened species is overwhelmingly tropical rain forest, where the greatest threat to plants is anthropogenic habitat conversion, for arable and livestock agriculture, and harvesting of natural resources. Gymnosperms (e.g. conifers and cycads) are the most threatened group, while a third of plant species included in this study have yet to receive an assessment or are so poorly known that we cannot yet ascertain whether they are threatened or not. This study provides a baseline assessment from which trends in the status of plant biodiversity can be measured and periodically reassessed.Peer reviewe
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