867 resultados para cover
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The aim of this study was to evaluate the production of biomass and grain cover crops, yield components, and grain yield of rice in Mozambique. The study was conducted in two sites located in the province of Cabo Delgado, in Mozambique.
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2008
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2016
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O presente estudo quantificou os efeitos da fertilização mineral e da cobertura do solo com uma leguminosa (Pueraria phaseoloides (Roxb) Benth.) sobre a dinâmica de nutrientes no sistema solo-planta.
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2016
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We studied the Paraíba do Sul river watershed , São Paulo state (PSWSP), Southeastern Brazil, in order to assess the land use and cover (LULC) and their implication s to the amount of carbon (C) stored in the forest cover between the years 1985 and 2015. Th e region covers a n area of 1,395,975 ha . We used images made by the Operational Land Imager (OLI) sensor (OLI/Landsat - 8) to produce mappings , and image segmentation techniques to produce vectors with homogeneous characteristics. The training samples and the samples used for classification and validation were collected from the segmented image. To quantify the C stocked in aboveground live biomass (AGLB) , we used an indirect method and applied literature - based reference values. The recovery of 205,690 ha of a secondary Native Forest (NF) after 1985 sequestered 9.7 Tg (Teragram) of C . Considering the whole NF area (455,232 ha), the amount of C accumulated al ong the whole watershed was 3 5 .5 Tg , and the whole Eucalyptus crop (EU) area (113,600 ha) sequester ed 4. 4 Tg of C. Thus, the total amount of C sequestered in the whole watershed (NF + EU) was 3 9 . 9 Tg of C or 1 45 . 6 Tg of CO 2 , and the NF areas were responsible for the large st C stock at the watershed (8 9 %). Therefore , the increase of the NF cover contribut es positively to the reduction of CO 2 concentration in the atmosphere, and Reducing Emissions from Deforestation and Forest Degradation (REDD + ) may become one of the most promising compensation mechanisms for the farmers who increased forest cover at their farms.
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Extreme sports have unfortunately gained a reputation for being risk focused and adrenaline fuelled. This perspective has obscured the place of the natural world, making extreme athletes appear to seek to conquer, compete against or defeat natural forces. In contrast, this paper explores findings from a larger hermeneutic phenomenological study that suggests extreme sports can initiate a positive change in participants’ relationships with the natural world. Data sources include first-hand accounts of extreme sports participants such as biographies, videos, papers and journals as well as interviews with ten male and five female extreme sports participants. Reports indicate that extreme sport participants develop feelings of connection to the natural world and describe themselves as being at one with the natural world or connected through a life enhancing energy. The paper draws on theoretical perspectives in ecopsychology which suggest that feeling connected to nature leads to a desire to care for the natural world and contributes to more environmentally sustainable practices.
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Three anaerobic ponds used to store and treat piggery wastes were fully covered with permeable materials manufactured from polypropylene geofabric, polyethylene shade cloth and supported straw. The covers were assessed in terms of efficacy in reducing odour emission rates over a 40-month period. Odour samples were collected from the surface of the covers, the surface of the exposed liquor and from the surface of an uncovered (control) pond at one of the piggeries. Relative to the emission rate of the exposed liquor at each pond, the polypropylene, shade cloth and straw covers reduced average emission rates by 76%, 69% and 66% respectively. At the piggery with an uncovered control pond, the polypropylene covers reduced average odour emission rates by 50% and 41% respectively. A plausible hypothesis, consistent with likely mechanisms for the odour reduction and the olfactometric method used to quantifying the efficacy of the covers, is offered.
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This paper presents a detailed description of the influence of critical parameters that govern the vulnerability of columns under lateral impact loads. Numerical simulations are conducted by using the Finite Element program LS-DYNA, incorporating steel reinforcement, material models and strain rate effects. A simplified method based on impact pulse generated from full scale impact tests is used for impact reconstruction and effects of the various pulse loading parameters are investigated under low to medium velocity impacts. A constitutive material model which can simulate failures under tri-axial state of stresses is used for concrete. Confinement effects are also introduced to the numerical simulation and columns of Grade 30 to 50 concrete under pure axial loading are analysed in detail. This research confirmed that the vulnerability of the axially loaded columns can be mitigated by reducing the slenderness ratio and concrete grade, and by choosing the design option with a minimal amount of longitudinal steel. Additionally, it is evident that approximately a 50% increase in impact capacity can be gained for columns in medium rise buildings by enhancing the confinement effects alone. Results also indicated that the ductility as well as the mode of failure under impact can be changed with the volumetric ratio of lateral steel. Moreover, to increase the impact capacity of the vulnerable columns, a higher confining stress is required. The general provisions of current design codes do not sufficiently cover this aspect and hence this research will provide additional guidelines to overcome the inadequacies of code provisions.
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This is the lead article for an issue of M/C Journal on the theme ‘obsolete.’ It uses the history of the International Journal of Cultural Studies (of which the author has been editor since 1997) to investigate technological innovations and their scholarly implications in academic journal publishing; in particular the obsolescence of the print form. Print-based elements like cover-design, the running order of articles, special issues, refereeing and the reading experience are all rendered obsolete with the growth of online access to individual articles. The paper argues that individuation of reading choices may be accompanied by less welcome tendencies, such as a decline in collegiality, disciplinary innovation, and trust.
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This document provides the findings of an international review of investment decision-making practices in road asset management. Efforts were concentrated on identifying the strategic objectives of agencies in road asset management, establishing and understanding criteria different organisations adopted and ascertaining the exact methodologies used by different countries and international organisations. Road assets are powerful drivers of economic development and social equity. They also have significant impacts on the natural and man-made environment. The traditional definition of asset management is “A systematic process of maintaining, upgrading and operating physical assets cost effectively. It combines engineering principles with sound business practices and economic theory and it provides tools to facilitate a more organised, logical approach to decision-making” (US Dept. of Transportation, 1999). In recent years, the concept has been broadened to cover the complexity of decision making, based on a wider variety of policy considerations as well as social and environmental issues rather than is covered by Benefit-Cost analysis and pure technical considerations. Current international practices are summarised in table 2. It was evident that Engineering-economic analysis methods are well advanced to support decision-making. A range of tools available supports performance predicting of road assets and associated cost/benefit in technical context. The need for considering triple plus one bottom line of social, environmental and economic as well as political factors in decision-making is well understood by road agencies around the world. The techniques used to incorporate these however, are limited. Most countries adopt a scoring method, a goal achievement matrix or information collected from surveys. The greater uncertainty associated with these non-quantitative factors has generally not been taken into consideration. There is a gap between the capacities of the decision-making support systems and the requirements from decision-makers to make more rational and transparent decisions. The challenges faced in developing an integrated decision making framework are both procedural and conceptual. In operational terms, the framework should be easy to be understood and employed. In philosophical terms, the framework should be able to deal with challenging issues, such as uncertainty, time frame, network effects, model changes, while integrating cost and non-cost values into the evaluation. The choice of evaluation techniques depends on the feature of the problem at hand, on the aims of the analysis, and on the underlying information base At different management levels, the complexity in considering social, environmental, economic and political factor in decision-making is different. At higher the strategic planning level, more non-cost factors are involved. The complexity also varies based on the scope of the investment proposals. Road agencies traditionally place less emphasis on evaluation of maintenance works. In some cases, social equity, safety, environmental issues have been used in maintenance project selection. However, there is not a common base for the applications.
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Sexual harassment can be conceptualised as an interaction between harassers and targets. Utilising 23 detailed legal transcripts, this study explored evidence of a range of perpetrator tactics and target counter-tactics. These tactics can be readily fitted into the backfire framework, which proposes that powerful perpetrators of perceived unjust acts are likely to cover up the actions, devalue the target, reinterpret the events, use official channels to give an appearance of justice, and intimidate or bribe people involved. Targets can respond using counter-tactics of exposure, validation, reframing, mobilisation of support, and resistance. The findings have implications for raising awareness of harassing tactics and recommendations for effective informal responses in organisations.
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This paper presents a comparative study of primarily Australian (and limited international) practices and guidelines on Buildings Asset Management (BAM). The objective of this study was to identify potential gaps in current practices and potential areas of research for further improvement. The paper starts with an overview of BAM. Later sections cover current BAM practices and guidelines across different states of Australia; give a limited overview of international practices and concludes with the authors’ observations.
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One of the perceived Achilles heels of online citizen journalism is its perceived inability to conduct investigative and first-hand reporting. A number of projects have recently addressed this problem, with varying success: the U.S.-based Assignment Zero was described as "a highly satisfying failure" (Howe 2007), while the German MyHeimat.de appears to have been thoroughly successful in attracting a strong community of contributors, even to the point of being able to generate print versions of its content, distributed free of charge to households in selected German cities. In Australia, citizen journalism played a prominent part in covering the federal elections held on 24 November 2007; news bloggers and public opinion Websites provided a strong counterpoint to the mainstream media coverage of the election campaign (Bruns et al., 2007). Youdecide2007.org, a collaboration between researchers at Queensland University of Technology and media practitioners at the public service broadcaster SBS, the public opinion site On Line Opinion, and technology company Cisco Systems, was developed as a dedicated space for a specifically hyperlocal coverage of the election campaign in each of Australia's 150 electorates from the urban sprawls of Sydney and Brisbane to the sparsely populated remote regions of outback Australia. YD07 provided training materials for would-be citizen journalists and encouraged them to contribute electorate profiles, interview candidates, and conduct vox-pops with citizens in their local area. The site developed a strong following especially in its home state of Queensland, and its interviewers influenced national public debate by uncovering the sometimes controversial personal views of mainstream and fringe candidates. At the same time, the success of YD07 was limited by external constraints determined by campaign timing and institutional frameworks. As part of a continuing action research cycle, lessons learnt from Youdecide2007.org are going to be translated into further iterations of the project, which will cover the local government elections in the Australian state of Queensland, to be held in March 2008, and developments subsequent to these elections. This paper will present research outcomes from the Youdecide2007.org project. In particular, it will examine the roles of staff contributors and citizen journalists in attracting members, providing information, promoting discussion, and fostering community on the site: early indications from a study of interaction data on the site indicate notably different contribution patterns and effects for staff and citizen participants, which may point towards the possibility of developing more explicit pro-am collaboration models in line with the Pro-Am phenomenon outlined by Leadbeater & Miller (2004). The paper will outline strengths and weaknesses of the Youdecide model and highlight requirements for the successful development of active citizen journalism communities. In doing so, it will also evaluate the feasibility of hyperlocal citizen journalism approaches, and their interrelationship with broader regional, state, and national journalism in both its citizen and industrial forms.
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The lava park is surrounded by the volcanic mountains of Les Preses, revealed as the edges of a vast caldera and repeated at a human scale with low walls made up of small volcanic boulders. These walls are evidence of how successive communities have gradually worked amongst this lava flow to create arable land, supported by rich soils. The people saw the land prosper and learned how to maximise its productivity. Boulders that had come to the surface during agricultural cultivation were moved with human labour to create "artigas“, the characteristic pilings of volcanic stone. They have been used to raise and lower areas, to create shelter and exposure for their crops and to make caves for storage. Amongst all this, paths weave and cross. The whole place is made up of grey and black rocks with a constant cover of green crops or grass.