860 resultados para Enclosed steppe


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Title enclosed in ornamental border.

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"November 2000."

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marginal notes/ examined by M. Zacharia 8/24/89."

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The Southern Ocean (SO) plays a key role in modulating atmospheric CO2 via physical and biological processes. However, over much of the SO, biological activity is iron-limited. New in situ data from the Antarctic zone south of Africa in a region centered at -20°E - 25°E reveal a previously overlooked region of high primary production, comparable in size to the northwest African upwelling region. Here, sea ice together with enclosed icebergs is channeled by prevailing winds to the eastern boundary of the Weddell Gyre, where a sharp transition to warmer waters causes melting. This cumulative melting provides a steady source of iron, fuelling an intense phytoplankton bloom that is not fully captured by monthly satellite production estimates. These findings imply that future changes in sea-ice cover and dynamics could have a significant effect on carbon sequestration in the SO.

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The two sets of connected membranes induced in Kunjin virus-infected cells are characterized by the presence of NS3 helicase/protease in both, and by RNA-dependent RNA polymerase (RdRp) activity plus the associated double-stranded RNA (dsRNA) template in vesicle packets (VP), or by the absence of both the VP-specific markers in the convoluted membranes/paracrystalline arrays (CM/PC). Attempts were made to separate flavivirus-induced membranes by sedimentation or flotation analyses in density gradients of sucrose or iodixanol, respectively, after treatment of cell lysates by sonication, osmotic shock, or tryptic digestion. Only osmotic shock treatment provided suggestive evidence of separation. This was explored by flow cytometry analysis (FCA) of RdRp active membrane fractions from a sucrose gradient, using dual fluorescent labelling via antibodies to NS3 and dsRNA. FCA revealed the presence of a dual labelled membrane population indicative of VP, and in a faster sedimenting fraction a membrane population able to be labelled only in NS3, representative of CM/PC and associated (R)ER. It was postulated that osmotic shock ruptured the bounding membrane of the VP, releasing the enclosed small vesicles associated with the Kunjin virus replication complex characterized previously. Notably, the presence of the full spectrum of nonstructural proteins in some membrane fractions was not a reliable marker for RdRp activity. These experiments may provide the opportunity for isolation of relatively pure flavivirus replication complexes in their native membrane-associated state by fluorescence-activated cell sorting. (C) 2004 Elsevier B.V. All rights reserved.

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The influence of different light regimes on the germination of Australian and English populations of Phalaris paradoxa L. (awned canary-grass) seed was investigated to determine the impact of changing tillage practices on weed infestation. Seeds of all biotypes were highly viable, but differed in levels of innate dormancy (26-99%). In one experiment seed from a single Australian biotype, either enclosed in the spikelet glumes or having the spikelet glumes removed, were exposed to nine light treatments. Germination was stimulated by red and white light, but was inhibited by far-red light. Time to 50%, germination was less for seed enclosed in the spikelet glumes than for naked caryopses, although the final percentage of seed germinating when still enclosed in the spikelet glumes was significantly lower than for naked caryopses. In another experiment, six Australian and English biotypes with varying dormancy characteristics were exposed to eight light treatments. Red light did not stimulate germination in the deeply dormant biotype, however stimulated all other biotypes. Germination in darkness was below 20% in all biotypes except for one where germination was 51%. To overcome dormancy seeds were imbibed and placed in darkness at 16degreesC for either 7 or 14 days prior to exposure to red or white light for a single 15-min period. Dormancy in all biotypes was overcome indicating that a period of burial may decrease the dormancy level and increase seed sensitivity to light. This increased light sensitivity suggests that exposure to light during tillage may stimulate germination in P. paradoxa seed.

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Postharvest abscission of Geraldton waxflower (Chamelaucium uncinatum Schauer) flower buds and flowers is ethylene-mediated. Exposure of floral organs to exogenous ethylene (1 mu L L-1) for 6 h at 20 degrees C induced separation at a morphologically and anatomically distinct abscission zone between the pedicel and. oral tube. Flower buds with opening petals and flowers with a nectiferous hypanthium were generally more responsive to exogenous ethylene than were flower buds enclosed in shiny bracteoles and aged (senescing) flowers. The anatomy of abscission-zone cells did not change at sequential stages of floral development from immature buds to aged flowers. The zone comprised a layer of small, laterally elongated-to-rounded, closely packed and highly protoplasmic parenchyma cells. Abscission occurred at a two- to four-cell-wide separation layer within the abscission zone. The process involved degradation of the middle lamella between separation layer cells. Following abscission, cells on both the proximal and distal faces of the separation layer became spherical, loosely packed and contained degenerating protoplasm. Central vascular tissues within the surrounding band of separation layer cells became torn and fractured. For flower buds, bracteoles that enclose the immature floral tube also separated at an abscission zone. However, this secondary abscission zone appeared less sensitive to ethylene than the primary ( central). oral-tube abscission zone as bracteoles generally only completely abscised when exposed to 10 mu L L-1 ethylene for the longer period of 24 h at 20 degrees C. The smooth surfaces of abscised separation-layer cells suggest that hydrolase enzymes degrade the middle lamella between adjacent cell walls.

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Water level and current measurements from two virtually enclosed South Pacific atolls, Manihiki and Rakahanga, support a new lagoon flushing mechanism which is driven by waves and modulated by the ocean tide for virtually enclosed atolls. This is evident because the lagoon water level remains above the ocean at all tidal phases (i.e., ruling out tidal flushing) and because the average lagoon water level rises significantly during periods with large waves. Hence, we develop a model by which the lagoons are flushed by waves pumping of ocean water into the lagoon and gravity draining water from the lagoon over the reef rim. That is, the waves on the exposed side push water into the lagoon during most of the tidal cycle while water leaves the lagoon on the protected side for most of the tidal cycle. This wave-driven through flow flushing is shown to be more efficient than alternating tidal flushing with respect to water renewal. Improved water quality should therefore be sought through enhancement of the natural wave pumping rather than by blasting deep channels which would change the system to an alternating tide-driven one.

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Invasive vertebrate pests together with overabundant native species cause significant economic and environmental damage in the Australian rangelands. Access to artificial watering points, created for the pastoral industry, has been a major factor in the spread and survival of these pests. Existing methods of controlling watering points are mechanical and cannot discriminate between target species. This paper describes an intelligent system of controlling watering points based on machine vision technology. Initial test results clearly demonstrate proof of concept for machine vision in this application. These initial experiments were carried out as part of a 3-year project using machine vision software to manage all large vertebrates in the Australian rangelands. Concurrent work is testing the use of automated gates and innovative laneway and enclosure design. The system will have application in any habitat throughout the world where a resource is limited and can be enclosed for the management of livestock or wildlife.

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Eighteen Angus steers exposed to high heat load conditions were used to assess the effectiveness of four spray cooling systems, on reducing the effects of heat load, the impact on microclimate and water usage. The steers were housed in groups of nine in a fully enclosed shed and were exposed to high heat load conditions for four days. The cooling systems used were water applied via a hose, via overhead sprinklers, via sprinklers at leg height and via misters. The water used was approximately 31 oC and contained 3% NaCl. Fans were used to ensure adequate air movement over the cattle. The animal parameters measured were feed intake, respiration rate, panting score and behaviour. Climatic factors were ambient temperature and wet bulb temperature. Ammonia levels were also measured. The hose, overhead sprinklers and misting were successful in reducing heat load on the cattle. The leg wetting system did not work because the dominant cattle blocked access to the sprinklers. The misting system used the most water (5483 L) and the hose the least (845 L). The application of water had minor impacts on wet bulb temperature, but resulted in significant reductions in dry bulb temperatures.

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Coral reefs, excellent climatic and environmental archives in tropical oceans, are widely distributed in the South China Sea (SCS), which is the largest enclosed marginal sea of western Pacific, covering over 20° in latitude and different climate conditions. Our recent research in the SCS focuses on coral-based high-resolution climate reconstruction and coral reef ecological responses using geochemical and U-series geochronological tools, which provide an ideal opportunity for understanding of Holocene climate processes and events. Some major research highlights are summarized below:

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Os estudos sobre expatriados, tanto no âmbito nacional quanto internacional, normalmente tratam de aspectos administrativos relativos ao processo de expatriação, como, por exemplo, as dificuldades de adaptação do indivíduo e de sua família, bem como o prejuízo que um programa mal sucedido poderia trazer para a organização. O objetivo desse estudo foi descrever cinco indicadores psicossociais de saúde positiva (bem-estar subjetivo, bemestar no trabalho, percepção de suporte social, percepção de suporte organizacional e otimismo) em empregados expatriados. Foi utilizada uma amostra escolhida por conveniência, composta por 16 pessoas, sendo 8 do sexo masculino e 8 do sexo feminino e que já haviam participado ou estavam participando de programas organizacionais de expatriação. O instrumento de coleta de dados foi um questionário de auto-preenchimento composto por oito medidas que aferiram as variáveis incluídas no estudo (satisfação geral com a vida, afetos positivos e negativos, satisfação no trabalho, envolvimento com o trabalho, comprometimento organizacional afetivo, percepções de suporte social e organizacional e otimismo). Foram realizadas análises estatísticas descritivas, testadas diferenças entre médias, bem como calculados índices de correlação entre variáveis. Os resultados revelaram que os profissionais expatriados tiveram mais oportunidades de vivenciar sensações afetivas positivas do que negativas em suas experiências fora do seu país de origem, o que permite dizer que os expatriados tendem a níveis positivos de muito alegres, muito bem, muito felizes, muito satisfeitos, muito animados e muito contentes , logo eles mantiveram relativamente preservado o seu bem-estar subjetivo. Também foi possível observar que as suas maiores satisfações com a vida não eram advindas do trabalho e que eles pareciam demonstrar estar satisfeitos com suas relações interpessoais além de apresentar uma forte vinculação afetiva com o seu empregador. Resultado diferente foi obtido para envolvimento com o trabalho revelando que as tarefas não conseguiam manter o expatriado totalmente absorvido por elas durante o período de expatriação. O estudo revelou também que os expatriados percebem receber maior apoio emocional de seus familiares, amigos e parentes do que suporte prático. Quanto à percepção de suporte organizacional foi observado que eles não acreditam, incondicionalmente, no apoio da organização em que estão inseridos. Os resultados mostraram ainda que os expatriados mantêm uma expectativa positiva quanto ao futuro, sinalizando um senso levemente acentuado de otimismo. Foi possível observar também algumas correlações significativas entre as dimensões de BES e BET. Com base nestes resultados existem indícios de saúde positiva entre os profissionais pesquisados, visto que eles parecem estar de bem com a vida pessoal e relativamente bem no trabalho, mantendo crenças medianas de suporte social e organizacional. Os resultados do estudo poderão contribuir para a compreensão do quadro psicológico dos indivíduos expatriados e, ao mesmo tempo, oferecerem uma melhor fundamentação conceitual para estudiosos do tema, assim como suscitar nos gestores reflexões acerca de ações políticas para o monitoramento da saúde psíquica dos empregados que tenham participado ou estejam participando desse tipo de programa organizacional.(AU)

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The most significant environmental change to support people who want to give up smoking is the legislation to ban smoking in public places. Following Scotland in March 2006, and Wales and Northern Ireland in April 2007, England moves one step closer to being smoke free on 1 July 2007, when it becomes illegal to smoke in almost every enclosed public place and workplace. Social marketing will be used to support this health promoting policy and will become more prominent in the design of health promotion campaigns of the future. Social marketing is not a new approach to promoting health but its adoption by the Government does represent a paradigm shift in the challenge to change public opinion and social norms. As a result some behaviours, like smoking or excessive alcohol consumption, will no longer be socially acceptable. The Department of Health has decided that social marketing should be used in England to guide all future health promotion efforts directed at achieving behavioural goals. This paradigm shift was announced in Chapter 2 of the “Choosing health” White Paper with its emphasis on the consumer, noting that a wide range of lifestyle choices are marketed to people, although health as a commodity itself has not been marketed. The DoH has an internal social marketing development unit to integrate social marketing principles into its work and ensure that providers deliver. The National Centre for Social Marketing has funding to provide ongoing support, to build capacity and capability in the workforce. This article describes the distinguishing features of the social marketing approach. It seeks to answer some questions. Is this really a new idea, a paradigm shift, or simply a change in terminology? What do the marketing principles offer that is new, or are they merely familiar ideas repackaged in marketing jargon? Will these principles be more effective than current health promotion practice and, if so, how does it work? Finally, what are the implications for community pharmacy?

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A fundamental if poorly understood problem that hydrogels display is the tendency of these contact lens materials to dehydrate, causing certain complications of the corneal epithelium. However, recent studies have indicated that the evaporation rate of water from different hydrogel lenses is the same and the severity of conditions such as corneal staining is controlled by the states of water in the material. A study was therefore undertaken which concluded that increased corneal desiccating staining occurred as the proportion of water existing in the bound state decreased. The possibility of using dehydrated hydrogels as packaging materials with desiccating properties has also been investigated. As hydrogels have a high affinity for water they have adequate ability to function as a moisture scavenger in an enclosed atmosphere. It was concluded that this ability is maximised by a high total water content and an increase in the proportion of this water existing in the bound state for the material when it is fully hydrated. N-vinyl pyrrolidone has a low reactivity in vinyl polymerisation reactions which results in polymers with local domains of the same chemical type which can lead to deposition. As contact lenses comprising of this monomer are susceptible to deposition, a monomer with a higher reactivity in vinyl polymerisations is acryloylmorpholine and its incorporation in favour of NVP is encouraged. Unfortunately a large proportion of high EWC hydrogels are mechanically weak and attempts to increase this property by increasing hydrophobicity or cross-linking results in a decrease in EWC. Monomers with the potential to carry a positive charge were incorporated into a high EWC, AMO-HEMA copolymer and the physical properties were investigated. Although EWC increased, mechanical properties decreased only slightly. Therefore simultaneous incorporation of a positively charged monomer and a negatively charged monomer was investigated. The resulting copolymers showed increased water content and increased initial modulus. A technique for measuring the coefficient of friction of contact lenses during lubrication has been developed.