1,116 research outputs found

    Spatial and temporal distribution of North Atlantic tropical cyclones

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    The aim of this work is to provide a classification of tropical cyclones (TC) according to their location, month of genesis and their lifecycles and to study the role of African Easterly Waves (AEWs) in North Atlantic cyclogenesis. Between 1980 and 2004, 269 tropical cyclones (TCs) were formed over the North Atlantic, 77% of which occurred during the August-October period and 95% of major hurricanes (TCs in which the maximum sustained wind was greater or equal to 50 m/s) were generated in the same period. The high activity of the August-October period was due to the favourable thermodynamic and dynamic conditions that simultaneously exist over the main development region (MDR). A classification of TCs according to their months of genesis and lifecycles showed that TCs generated before August and after October have no preferential latitude and longitude of genesis. TCs generated at the East of 60°W and over the southern part of the MDR have long lifecycles. Major hurricanes have long lifecycles and are generally initiated over the southern part of the MDR and East of 60°W. The spatial representation of the cyclogenesis area shows that cyclones are generated along two main axes; one is situated around 12.5°N (southern axis) and the second around 27.5°N (northern axis). 56% (44%) of TCs are generated over the southern axis (northern axis). 92% of TCs initiated along the southern axis originate from African Easterly Waves. While 64% of those generated over the northern axis are linked to mid-latitude baroclinic systems and upper level cold lows. This study contributes to a better understanding of North Atlantic cyclogenesis characteristics as well as the role of AEWs

    Complexities of teaching — features of teacher education programs and professional learning practices to support their development

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    This publication is the editorial for Vol 15.2 of MTED which summarises and synthesises the articles published in the issue. The extent to which those whose learning is the focus controlled the learning situations in which they participated is the key concept discussed and the factors contributing to the extent of control are elucidated.<br /

    Cash Crop and Foodgrain Productivity in Senegal: Historical View, New Survey Evidence, and Policy Implications

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    Crop Production/Industries, Productivity Analysis, Downloads July 2008 - June 2009: 10,

    International multi-perspective analyses of classroom activity

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    This editorial captures the essence of each of the papers in this journal and synthesises the findings to highlight the complexity of developing practices that enable students to develop mathematical understandings. Papers described and discussed come from sources internal and external to Australasia. They include new perspectives on analysis of classroom practices, analyses of mathematical registers and mathematical language in classroom activity, action research of a teacher developing new pedagogical understandings, and various analyses associated with teacher education (pre-service teacher programs, interactions between pre-service teachers and their mentors, and how limited content knowledge can affect teacher interpretation of classroom activity. The editorial captures many of the complexities highlighted in the papers and points to the enormity of the expertise required to optimise the teaching of mathematics.. <br /

    Arizona Clinical Research Workforce Survey

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    Objective: We characterize the current clinical research workforce in Arizona with the goal of identifying possible educational training gaps for the future workforce. Background: The science community, government entities, educational institutions, and community programs continue to advocate for additional funding and resources to educate the bioscience workforce, of which clinical research is a part. However, there is little evidence that additional training and/or education is needed within the clinical research profession. Method: We utilized an electronic survey tool that was designed to solicit workforce data from clinical research professionals actively working or seeking employment in the field of clinical research within the state of Arizona. Distributed by email, the survey was sent to professional research organizations and associations, employment agencies, academic institutions, LinkedIn groups, and through a distribution list held by the Arizona Department of Health. Results were analyzed using a mixed method of descriptive statistics and qualitative analysis. Results: The majority of respondents to the survey were female and were between the ages of 41 and 60. When asked whether respondents thought that clinical research professionals should undergo formalized training through a college or university program that culminates in professional licensure, more than one-third indicated “no,”, while the rest of the respondents indicated “yes” (29.8%) or “no opinion” (33.8%). Respondents who answered “no,” had concerns related to scope of practice, status quo, diversity of practice, and cost. Respondents who answered “yes,” indicated that professional licensure would raise levels of quality and levels of understanding. More than half of respondents indicated that they were required to obtain continuing education and that training in “good clinical practice” and “regulatory requirements” was of most interest. Conclusion: The survey focused on the current educational and training needs of the clinical research workforce, yet provided limited general education and training needs for the future of the profession. In order to determine educational gaps within the profession, distinctions in job titles and responsibilities are required to control for the diversity within the profession. Additional research is needed to identify the expectations of employers, professional organizations, and government agencies so that higher education can prepare the future clinical research workforce with resource allocations. Application: This survey offers a foundation for future research to investigate resource allocation within the clinical research area of bioscience education

    Mechanisms of Bacterial Extracellular Electron Exchange.

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    The biochemical mechanisms by which microbes interact with extracellular soluble metal ions and insoluble redox-active minerals have been the focus of intense research over the last three decades. The process presents two challenges to the microorganism; firstly electrons have to be transported at the cell surface, which in Gram negative bacteria presents an additional problem of electron transfer across the ~ 6 nm of the outer membrane. Secondly the electrons must be transferred to or from the terminal electron acceptors or donors. This review covers the known mechanisms that bacteria use to transport electrons across the cell envelope to external electron donors/acceptors. In Gram negative bacteria electron transfer across the outer membrane involves the use of an outer membrane ÎČ-barrel and cytochrome. These can be in the form of a porin-cytochrome protein, such as Cyc2 of Acidothiobacillus ferrioxydans, or a multiprotein porin-cytochrome complex like MtrCAB of Shewanella oneidensis MR-1. For mineral respiring organisms there is the additional challenge of transferring the electrons from the cell to mineral surface. For the strict anaerobe Geobacter sulfurreducens this requires electron transfer through conductive pili to associated cytochrome OmcS that directly reduces Fe(III)oxides, while the facultative anaerobe S. oneidensis MR-1 accomplishes mineral reduction through direct membrane contact, contact through filamentous extentions and soluble flavin shuttles, all of which require the outer membrane cytochromes MtrC and OmcA in addition to secreted flavin

    Proton and cadmium adsorption by the archaeon Thermococcus zilligii: Generalising the contrast between thermophiles and mesophiles as sorbents

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    Adsorption by microorganisms can play a significant role in the fate and transport of metals in natural systems. Surface complexation models (SCMs) have been applied extensively to describe metal adsorption by mesophilic bacteria, and several recent studies have extended this framework to thermophilic bacteria. We conduct acid-base titrations and batch experiments to characterise proton and Cd adsorption onto the thermophilic archaeon Thermococcus zilligii. The experimental data and the derived SCMs indicate that the archaeon displays significantly lower overall sorption site density compared to previously studied thermophilic bacteria such Anoxybacillus flavithermus, Geobacillus stearothermophilus, G. thermocatenulatus, and Thermus thermophilus. The thermophilic bacteria and archaea display lower sorption site densities than the mesophilic microorganisms that have been studied to date, which points to a general pattern of total concentration of cell wall adsorption sites per unit biomass being inversely correlated to growth temperature

    A methodological framework for assessing agreement between cost-effectiveness outcomes estimated using alternative sources of data on treatment costs and effects for trial-based economic evaluations

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    A new methodological framework for assessing agreement between cost-effectiveness endpoints generated using alternative sources of data on treatment costs and effects for trial-based economic evaluations is proposed. The framework can be used to validate cost-effectiveness endpoints generated from routine data sources when comparable data is available directly from trial case report forms or from another source. We illustrate application of the framework using data from a recent trial-based economic evaluation of the probiotic Bifidobacterium breve strain BBG administered to babies less than 31 weeks of gestation. Cost-effectiveness endpoints are compared using two sources of information; trial case report forms and data extracted from the National Neonatal Research Database (NNRD), a clinical database created through collaborative efforts of UK neonatal services. Focusing on mean incremental net benefits at ÂŁ30,000 per episode of sepsis averted, the study revealed no evidence of discrepancy between the data sources (two-sided p values >0.4), low probability estimates of miscoverage (ranging from 0.039 to 0.060) and concordance correlation coefficients greater than 0.86. We conclude that the NNRD could potentially serve as a reliable source of data for future trial-based economic evaluations of neonatal interventions. We also discuss the potential implications of increasing opportunity to utilize routinely available data for the conduct of trial-based economic evaluations

    DIFFICULTÉS DE LA PARTICIPATION EN RECHERCHE- ACTION : retour d'expĂ©riences de modĂ©lisation d'accompagnement en appui Ă  l'amĂ©nagement du territoire au SĂ©nĂ©gal et Ă  la RĂ©union

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    International audienceComment aider les institutions et acteurs locaux à investir davantage les processus d'affectation des terres pour aménager leur territoire ? La décentralisation de l'aménagement du territoire engagée à la Réunion et au Sénégal est inachevée. Malgré l'arsenal législatif, les populations locales semblent peu impliquées dans les décisions les concernant en raison notamment de la difficulté à appréhender la complexité des systÚmes d'interactions entre dynamiques sociales et environnementales. Le projet Domino vise à accompagner les processus de décision en proposant aux acteurs de construire et d'explorer des scenarii prospectifs d'affectation des terres. Cette expérience de modélisation participative repose sur une dynamique partenariale complexe sur chaque terrain, source de difficultés. Conscients des dérives potentielles, nous discutons la nécessité de construire une démarche qualité de notre recherche-action. Mots clés : montage de partenariat, démarche qualité, modÚle, changement social, ComMod, interdisciplinarité, décentralisation, foncier, Sénégal, Réunio
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