864 resultados para Plant biology|Genetics|Evolution and Development


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Despite the growing intensity of the debate about environmental management, it is only recently that rural practice surveyors have become aware of its significance and potential. Consequently, few surveyors are yet in a position to offer professional advice, despite evidence from the RICS's client needs survey that nearly half of all existing clients require more advice on environmental matters. As a prerequisite to becoming involved in environmental management, it is clear that chartered surveyors have to develop new skills alongside new perceptions of their work. Rather than being conterminous, however, the alignment of these attributes reflects a fundamental tension. This is focused on the dichotomy between the strategic construction of the environment as a basis for realigning corporate policy and the more limited evocation of environmentalism as potential new business. This paper seeks to explore the nature and policy context of sustainable development, in the process examining its significance for rural chartered surveyors. In doing so, the paper will seek to contrast the essentially anthropocentric utilitarianism of surveyors' current attitudes with the radical agenda inferred by a more ecocentric, sustainable development approach to professional management and advice. The paper will conclude with a discussion about how far the principles of sustainable development can be incorporated into the management of surveying businesses, and what this implies for the future of the rural practice chartered surveyor as land manager.

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In recognizing 11 official languages, the 1996 South African Constitution provides a context for the management of diversity with important implications for the redistribution of wealth and power. The development and implementation of the language-in-education policies which might be expected to flow from the Constitution, however, have been slow and ineffective. One of the casualties of government procrastination has been African language publishing. In the absence of well-resourced bilingual education, most learners continue to be taught through the medium of English as a second language. Teachers are reluctant to use more innovative pedagogies without the support of adequate African language materials and publishers are cautious about producing such materials. Nonetheless, activity in this sector offers many opportunities for African language speakers. This paper explores the challenges and constraints for African language publishing for children and argues that market forces and language policy need to work in mutually reinforcing ways. Further progress is necessarily dependent on the political will to implement language-in-education policies that promote additive bilingualism and, in the process, guarantee sales for risk-averse publishers.

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In situ high resolution aircraft measurements of cloud microphysical properties were made in coordination with ground based remote sensing observations of a line of small cumulus clouds, using Radar and Lidar, as part of the Aerosol Properties, PRocesses And InfluenceS on the Earth's climate (APPRAISE) project. A narrow but extensive line (~100 km long) of shallow convective clouds over the southern UK was studied. Cloud top temperatures were observed to be higher than −8 °C, but the clouds were seen to consist of supercooled droplets and varying concentrations of ice particles. No ice particles were observed to be falling into the cloud tops from above. Current parameterisations of ice nuclei (IN) numbers predict too few particles will be active as ice nuclei to account for ice particle concentrations at the observed, near cloud top, temperatures (−7.5 °C). The role of mineral dust particles, consistent with concentrations observed near the surface, acting as high temperature IN is considered important in this case. It was found that very high concentrations of ice particles (up to 100 L−1) could be produced by secondary ice particle production providing the observed small amount of primary ice (about 0.01 L−1) was present to initiate it. This emphasises the need to understand primary ice formation in slightly supercooled clouds. It is shown using simple calculations that the Hallett-Mossop process (HM) is the likely source of the secondary ice. Model simulations of the case study were performed with the Aerosol Cloud and Precipitation Interactions Model (ACPIM). These parcel model investigations confirmed the HM process to be a very important mechanism for producing the observed high ice concentrations. A key step in generating the high concentrations was the process of collision and coalescence of rain drops, which once formed fell rapidly through the cloud, collecting ice particles which caused them to freeze and form instant large riming particles. The broadening of the droplet size-distribution by collision-coalescence was, therefore, a vital step in this process as this was required to generate the large number of ice crystals observed in the time available. Simulations were also performed with the WRF (Weather, Research and Forecasting) model. The results showed that while HM does act to increase the mass and number concentration of ice particles in these model simulations it was not found to be critical for the formation of precipitation. However, the WRF simulations produced a cloud top that was too cold and this, combined with the assumption of continual replenishing of ice nuclei removed by ice crystal formation, resulted in too many ice crystals forming by primary nucleation compared to the observations and parcel modelling.

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Bright aurorae can be excited by the acceleration of electrons into the atmosphere in violation of ideal magnetohydrodynamics. Modelling studies predict that the accelerating electric potential consists of electric double layers at the boundaries of an acceleration region but observations suggest that particle acceleration occurs throughout this region. Using multi-spacecraft observations from Cluster we have examined two upward current regions on 14 December 2009. Our observations show that the potential difference below C4 and C3 changed by up to 1.7 kV between their respective crossings, which were separated by 150 s. The field-aligned current density observed by C3 was also larger than that observed by C4. The potential drop above C3 and C4 was approximately the same in both crossings. Using a novel technique of quantitatively comparing the electron spectra measured by Cluster 1 and 3, which were separated in altitude, we determine when these spacecraft made effectively magnetically conjugate observations and use these conjugate observations to determine the instantaneous distribution of the potential drop in the AAR. Our observations show that an average of 15% of the potential drop in the AAR was located between C1 at 6235 km and C3 at 4685 km altitude, with a maximum potential drop between the spacecraft of 500~V and that the majority of the potential drop was below C3. By assuming a spatial invariance along the length of the upward current region, we discuss these observations in terms of temporal changes and the vertical structure of the electrostatic potential drop and in the context of existing models and previous observations single- and multi-spacecraft observations.

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With particular reference to its role in the corporate real estate supply chain, this paper focuses on how the serviced office sector in the UK has evolved and changed over the last decade. A qualitative research approach involving 21 semi-structured interviews with corporate clients of serviced office operators was used to address a number of issues regarding the perceptions of users of serviced offices. It is concluded that the serviced office sector has become an established sector of the UK’s commercial real estate market providing an essential product for many corporate organisations. The serviced office sector has been relatively nimble and a range of operational models have emerged. It was found that corporate organisations use serviced office space and services in order to align workforce change with portfolio change, to transfer risk, for short-term project space, as temporary overflow space, to pilot a new location, to become familiar with a specific geographical marketplace or simply to gain an initial presence in an area.