995 resultados para Identity Products


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Base catalysed reaction of the tricyclic ketone (6 ⇌ 7) with methylvinyl ketone gave the tetracyclic ketols, 11, 13, 15, 16, and the pentacyclic ketols, 12, 17. With phenylvinyl ketone, the tetracyclic ketol (18) was formed. The stereostructures of the ketols were identified by X-Ray diffraction. The base-catalysed title reactions gave the cyclic ketols and derived compounds shown below whose structures were identified by X-ray diffraction.

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In this paper, the statistical properties of tropical ice clouds (ice water content, visible extinction, effective radius, and total number concentration) derived from 3 yr of ground-based radar–lidar retrievals from the U.S. Department of Energy Atmospheric Radiation Measurement Climate Research Facility in Darwin, Australia, are compared with the same properties derived using the official CloudSat microphysical retrieval methods and from a simpler statistical method using radar reflectivity and air temperature. It is shown that the two official CloudSat microphysical products (2B-CWC-RO and 2B-CWC-RVOD) are statistically virtually identical. The comparison with the ground-based radar–lidar retrievals shows that all satellite methods produce ice water contents and extinctions in a much narrower range than the ground-based method and overestimate the mean vertical profiles of microphysical parameters below 10-km height by over a factor of 2. Better agreements are obtained above 10-km height. Ways to improve these estimates are suggested in this study. Effective radii retrievals from the standard CloudSat algorithms are characterized by a large positive bias of 8–12 μm. A sensitivity test shows that in response to such a bias the cloud longwave forcing is increased from 44.6 to 46.9 W m−2 (implying an error of about 5%), whereas the negative cloud shortwave forcing is increased from −81.6 to −82.8 W m−2. Further analysis reveals that these modest effects (although not insignificant) can be much larger for optically thick clouds. The statistical method using CloudSat reflectivities and air temperature was found to produce inaccurate mean vertical profiles and probability distribution functions of effective radius. This study also shows that the retrieval of the total number concentration needs to be improved in the official CloudSat microphysical methods prior to a quantitative use for the characterization of tropical ice clouds. Finally, the statistical relationship used to produce ice water content from extinction and air temperature obtained by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite is evaluated for tropical ice clouds. It is suggested that the CALIPSO ice water content retrieval is robust for tropical ice clouds, but that the temperature dependence of the statistical relationship used should be slightly refined to better reproduce the radar–lidar retrievals.

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Although the role of the academic head of department (HoD) has always been important to university management and performance, an increasing significance given to bureaucracy, academic performance and productivity, and government accountability has greatly elevated the importance of this position. Previous research and anecdotal evidence suggests that as academics move into HoD roles, usually with little or no training, they experience a problem of struggling to adequately manage key aspects of their role. It is this problem – and its manifestations – that forms the research focus of this study. Based on the research question, “What are the career trajectories of academics who become HoDs in a selected post-1992 university?” the study aimed to achieve greater understanding of why academics become HoDs, what it is like being a HoD, and how the experience influences their future career plans. The study adopts an interpretive approach, in line with social constructivism. Edited topical life history interviews were undertaken with 17 male and female HoDs, from a range of disciplines, in a post-1992 UK university. These data were analysed using coding, categorisation and theme formation techniques and developing profiles of each of the respondents. The findings from this study suggest that academics who become HoDs not only need the capacity to assume a range of personal and professional identities, but need to regularly adopt and switch between them. Whether individuals can successfully balance and manage these multiple identities, or whether they experience major conflicts and difficulties within or between them, greatly affects their experiences of being a HoD and may influence their subsequent career decisions. It is claimed that the focus, approach and analytical framework - based on the interrelationships between the concepts of socialisation, identity and career trajectory - provide a distinct and original contribution to knowledge in this area. Although the results of this study cannot be generalised, the findings may help other individuals and institutions move towards a firmer understanding of the academic who becomes HoD - in relation to theory, practice and future research.

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Pollination is one of the most important ecosystem services in agroecosystems and supports food production. Pollinators are potentially at risk being exposed to pesticides and the main route of exposure is direct contact, in some cases ingestion, of contaminated materials such as pollen, nectar, flowers and foliage. To date there are no suitable methods for predicting pesticide exposure for pollinators, therefore official procedures to assess pesticide risk are based on a Hazard Quotient. Here we develop a procedure to assess exposure and risk for pollinators based on the foraging behaviour of honeybees (Apis mellifera) and using this species as indicator representative of pollinating insects. The method was applied in 13 European field sites with different climatic, landscape and land use characteristics. The level of risk during the crop growing season was evaluated as a function of the active ingredients used and application regime. Risk levels were primarily determined by the agronomic practices employed (i.e. crop type, pest control method, pesticide use), and there was a clear temporal partitioning of risks through time. Generally the risk was higher in sites cultivated with permanent crops, such as vineyard and olive, than in annual crops, such as cereals and oil seed rape. The greatest level of risk is generally found at the beginning of the growing season for annual crops and later in June–July for permanent crops.