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Search Results: 1 - 10 of 139074 matches for " K. Yates "
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CO32 concentration and pCO2 thresholds for calcification and dissolution on the Molokai reef flat, Hawaii
K. K. Yates ,R. B. Halley
Biogeosciences (BG) & Discussions (BGD) , 2006,
Abstract: The severity of the impact of elevated atmospheric pCO2 to coral reef ecosystems depends, in part, on how seawater pCO2 affects the balance between calcification and dissolution of carbonate sediments. Presently, there are insufficient published data that relate concentrations of pCO2 and CO32 to in situ rates of reef calcification in natural settings to accurately predict the impact of elevated atmospheric pCO2 on calcification and dissolution processes. Rates of net calcification and dissolution, CO32 concentrations, and pCO2 were measured, in situ, on patch reefs, bare sand, and coral rubble on the Molokai reef flat in Hawaii. Rates of calcification ranged from 0.03 to 2.30 mmol CaCO3 m 2 h 1 and dissolution ranged from –0.05 to –3.3 mmol CaCO3 m 2 h 1. Calcification and dissolution varied diurnally with net calcification primarily occurring during the day and net dissolution occurring at night. These data were used to calculate threshold values for pCO2 and CO32 at which rates of calcification and dissolution are equivalent. Results indicate that calcification and dissolution are linearly correlated with both CO32 and pCO2. Threshold pCO2 and CO32 values for individual substrate types showed considerable variation. The average pCO2 threshold value for all substrate types was 654±195 μatm and ranged from 467 to 1003 μatm. The average CO32 threshold value was 152±24 μmol kg 1, ranging from 113 to 184 μmol kg 1. Ambient seawater measurements of pCO2 and CO32 indicate that CO32 and pCO2 threshold values for all substrate types were both exceeded, simultaneously, 13% of the time at present day atmospheric pCO2 concentrations. It is predicted that atmospheric pCO2 will exceed the average pCO2 threshold value for calcification and dissolution on the Molokai reef flat by the year 2100.
CO2 3 concentration and pCO2 thresholds for calcification and dissolution on the Molokai reef flat, Hawaii
K. K. Yates,R. B. Halley
Biogeosciences Discussions , 2006,
Abstract: The severity of the impact of elevated atmospheric pCO2 to coral reef ecosystems depends, in part, on how seawater pCO2 affects the balance between calcification and dissolution of carbonate sediments. Presently, there are insufficient published data that relate concentrations of pCO2 and CO32 to in situ rates of reef calcification in natural settings to accurately predict the impact of elevated atmospheric pCO2 on calcification and dissolution processes. Rates of net calcification and dissolution, CO32 concentrations, and pCO2 were measured, in situ, on patch reefs, bare sand, and coral rubble on the Molokai reef flat in Hawaii. Rates of calcification ranged from 0.003 to 0.23 g CaCO3 m 2 h 1 and dissolution ranged from 0.005 to 0.33 g CaCO3 m 2 h 1. Calcification and dissolution varied diurnally with net calcification primarily occurring during the day and net dissolution occurring at night. These data were used to calculate threshold values for pCO2 and CO32 at which rates of calcification and dissolution are equivalent. Results indicate that calcification and dissolution are linearly correlated with both CO32 and pCO2. Threshold pCO2 and CO32 values for individual substrate types showed considerable variation. The average pCO2 threshold value for all substrate types was 654±195 μatm and ranged from 467 to 1003 μatm. The average CO3 - threshold value was 152±24 μmol kg-1, ranging from 113 to 184 μmol kg 1. Ambient seawater measurements of pCO2 and CO32 indicate that CO32 and pCO2 threshold values for all substrate types were both exceeded, simultaneously, 13% of the time at present day atmospheric pCO2 concentrations. It is predicted that atmospheric pCO2 will exceed the average pCO2 threshold value for calcification and dissolution on the Molokai reef flat by the year 2100.
Tendencias en la utilización de benzodiazepinas en farmacia privada
Yates K,Tamara; Catril M,Paola;
Revista chilena de neuro-psiquiatría , 2009, DOI: 10.4067/S0717-92272009000100002
Abstract: benzodiazepines are a group of major therapeutic drugs, but its abuse is associated with dependence and other adverse effects. its great for self consumption during the decade 1980-1989, led the health authority to establish in 1993 the control of prescribing and dispensing. the aim of this study was to determine the trend of use of these drugs by the population that goes to pharmacies. to that end, we examined the prescriptions dispensed for a period for three months covering the years 2003 and 2007, private pharmacies in the center of concepción, and supplemented with information gathered randomly using questionnaires to patients who attended these pharmacies. the variables were considered among others gender, reason for the prescription, a specialist prescribed, dispensed drugs. the results indicated that women were the most used them (72%). the reason for prescription was predominantly anxiolytic and hypnotic effects. general practitioners, psychiatrists and neurologists prescribed the drugs (45%, 23% and 12%), respectively. data that correspond to work performed in 1988 in concepción. among the drugs dispensed, clonazepam, alprazolam and lorazepam. it can be concluded that benzodiazepines are a group widely used in clinical treatment, and that trend continues over time, despite the implementation of the control of the prescription.
Tendencias en la utilización de benzodiazepinas en farmacia privada Trends in benzodiazepine use in private pharmacy
Tamara Yates K,Paola Catril M
Revista Chilena de Neuro-Psiquiatría , 2009,
Abstract: Las benzodiazepinas constituyen un grupo de fármacos de gran importancia terapéutica, pero su abuso se asocia a dependencia y a otros efectos adversos. Su gran consumo por automedicación durante la década 1980-1989, llevó a la autoridad sanitaria a establecer en el a o 1993 el control de su prescripción y dispensación. El objetivo de este estudio fue determinar la tendencia de utilización de estos medicamentos por la población que acude a las farmacias. Para ello se analizaron las recetas dispensadas durante un período de tres meses los a os 2003 y 2007 en farmacias privadas del centro de la ciudad de Concepción y se complementó con la información recabada al azar mediante cuestionario a pacientes que concurrieron a dichas farmacias. Las variables consideradas fueron entre otras, género, motivo de la prescripción, especialista que prescribe, fármacos más dispensados. Los resultados indicaron que las mujeres fueron las que más las utilizaron (70%). El motivo de prescripción fue mayoritariamente por los efectos hipnótico y ansiolítico. Los especialistas que más los prescribieron fueron médicos generales (45%), psiquiatras (23%) y neurólogos (12%). Datos que se corresponden con trabajos realizados en el a o 1988 en Concepción. Entre los fármacos más dispensados, clonazepam, alprazolam y lorazepam. Se puede concluir que las benzodiazepinas son un grupo terapéutico muy utilizado en clínica, y que la tendencia se mantiene a través del tiempo a pesar de la implementación del control de la prescripción. Benzodiazepines are a group of major therapeutic drugs, but its abuse is associated with dependence and other adverse effects. Its great for self consumption during the decade 1980-1989, led the health authority to establish in 1993 the control of prescribing and dispensing. The aim of this study was to determine the trend of use of these drugs by the population that goes to pharmacies. To that end, we examined the prescriptions dispensed for a period for three months covering the years 2003 and 2007, private pharmacies in the center of Concepción, and supplemented with information gathered randomly using questionnaires to patients who attended these pharmacies. The variables were considered among others gender, reason for the prescription, a specialist prescribed, dispensed drugs. The results indicated that women were the most used them (72%). The reason for prescription was predominantly anxiolytic and hypnotic effects. General practitioners, psychiatrists and neurologists prescribed the drugs (45%, 23% and 12%), respectively. Data that correspond to work perf
Coral Reefs and Ocean Acidification
Joan A. Kleypas,Kimberly K. Yates
Oceanography , 2009,
Abstract: Coral reefs were one of the first ecosystems to be recognized as vulnerable to ocean acidification. To date, most scientific investigations into the effects of ocean acidification on coral reefs have been related to the reefs’ unique ability to produce voluminous amounts of calcium carbonate. It has been estimated that the main reef-building organisms, corals and calcifying macroalgae, will calcify 10–50% less relative to pre-industrial rates by the middle of this century. This decreased calcification is likely to affect their ability to function within the ecosystem and will almost certainly affect the workings of the ecosystem itself. However, ocean acidification affects not only the organisms, but also the reefs they build. The decline in calcium carbonate production, coupled with an increase in calcium carbonate dissolution, will also diminish reef building and the benefits that reefs provide, such as high structural complexity that supports biodiversity on reefs, and breakwater effects that protect shorelines and create quiet habitats for other ecosystems, such as mangroves and seagrass beds. The focus on calcification in reefs is warranted, but the responses of many other organisms, such as fish, noncalcifying algae, and seagrasses, to name a few, deserve a close look as well.
Scanning Raman spectroscopy for characterizing compositionally spread films
A. Venimadhav,K. A. Yates,M. G. Blamire
Physics , 2004,
Abstract: Composition-spread La1-xSrxMnO3 thin films were prepared by pulsed laser deposition technique from LaMnO3 and SrMnO3 targets. The films were epitaxial with a continuous variation of the out of plane lattice parameter along the direction of composition gradient. Scanning Raman spectroscopy has been employed as a non-destructive tool to characterize the composition-spread films. Raman spectra showed the variation of the structural, Jahn Teller distortions and the presence of coexisting phases at particular compositions that are in agreement with the previous observation on the single crystal samples. Raman spectra on the continuous composition-spread film also reveal the effect of disorder and strain on the compositions.
Evolution of the Fermi surface of arsenic through the rhombohedral to simple-cubic phase transition: a Wannier interpolation study
Patricia K. Silas,Peter D. Haynes,Jonathan R. Yates
Physics , 2014, DOI: 10.1103/PhysRevB.88.134103
Abstract: The pressure dependence of the Fermi surface of arsenic is examined using the technique of Wannier interpolation, enabling a dense sampling of the Brillouin zone and the ability to capture fine features within it. Focusing primarily on the A7 to simple-cubic phase transition, we find that this semimetal to metal transition is accompanied by the folding of Fermi surfaces. The pressure dependence of the density of states (DOS) of arsenic indicates that the onset of the Peierls-type cubic to rhombohedral distortion is signified by the appearance of emerging van Hove singularities in the DOS, especially around the Fermi level. As we noted in an earlier study, high levels of convergence are consequently required for an accurate description of this transition.
Strong influence of boron precursor powder on the critical current density of MgB2
S. K. Chen,K. A. Yates,M. G. Blamire,J. L. MacManus-Driscoll
Physics , 2005, DOI: 10.1088/0953-2048/18/11/011
Abstract: The influence of the nature of the boron precursor on the superconducting properties of polycrystalline MgB2 was studied. Critical current densities for the MgB2 made from high purity amorphous boron are at least a factor of three higher than typical values measured for standard MgB2 samples made from amorphous precursors. Two possible mechanisms are proposed to account for this difference. Samples made from crystalline boron powders have around an order of magnitude lower Jc compared to those made from amorphous precursors. X-ray, Tc and resistivity studies indicate that this is as a result of reduced current cross section due to the formation of Mg-B-O phases. The samples made from amorphous B contain far fewer Mg-B-O phases than crystalline B despite the fact that the amorphous B contains more B2O3. The different reactivity rates of the precursor powders accounts for this anomaly.
Development of a 'toolkit' to identify medical students at risk of failure to thrive on the course: an exploratory retrospective case study
Janet Yates
BMC Medical Education , 2011, DOI: 10.1186/1472-6920-11-95
Abstract: The study group was drawn from five successive cohorts. Students who had experienced difficulties were identified in any of four ways: from Minutes of the Academic Progress Committee; by scanning examination lists at key stages (end of the first two years, and finals at the end of the clinical course); from lists of students flagged to the Postgraduate Deanery as in need of extra monitoring or support; and from progress files of those who had left the course prematurely. Relevant data were extracted from each student's course progress file into a customised database.1188 students were admitted over the five years. 162 (14%) were identified for the study, 75 of whom had failed to complete the course by October 2010. In the 87 who did graduate, a combination of markers in Years 1 and 2 identified over half of those who would subsequently have the most severe problems throughout the course. This 'toolkit' comprised failure of 3 or more examinations per year, an overall average of <50%, health or social difficulties, failure to complete Hepatitis B vaccination on time, and remarks noted about poor attitude or behaviour.A simple toolkit of academic and non-academic markers could be used routinely to help identify potential strugglers at an early stage, enabling additional support and guidance to be given to these students.Every year, a small number of undergraduate students at the University of Nottingham Medical School fail to make satisfactory progress on the course. Some have problems at all stages, others have sporadic difficulties, and a proportion fail to graduate at all, either leaving voluntarily or having their course terminated. In an earlier study we found that 10-15% of the annual intake were affected to some degree [1]. There is often a combination of causative factors, including difficulty in coping with the academic workload, health problems, and social issues such as not settling at university or having adverse personal or family circumstances. Some stude
When did they leave, and why? A retrospective case study of attrition on the Nottingham undergraduate medical course
Janet Yates
BMC Medical Education , 2012, DOI: 10.1186/1472-6920-12-43
Abstract: Relevant data on admission and course progress were extracted manually from the archived files of students who had failed to graduate from five recent consecutive cohorts (entry in 2000–2004 inclusive), using a customised Access database. Discrete categories of information were supplemented with free text entries.1188 students registered over the five-year entry period and 73 (6%) failed to graduate. The highest rates of attrition (46/1188, 4%) occurred during the first two years (largely preclinical studies), with 34 students leaving voluntarily, including 11 within the first semester, and 12 having their courses terminated for academic failure. Seventeen left at the end of the third year (Honours course plus early clinical practice) and the remaining ten during the final two clinical years. The reasons for attrition were not always clear-cut and often involved a mixture of academic, personal, social and health factors, especially mental health problems.The causes of attrition are complex. A small number of students with clear academic failure might require individual educational interventions for remediation. However, this could have substantial resource implications for the Faculty. Mental health problems predominate in late course attrition and may have been undisclosed for some time. The introduction of a structured exit interview may provide further insight, especially for those students who leave suddenly and unexpectedly early in the course.
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