239 research outputs found

    Changes in the activities of enzymes involved in nitrogen and sulphur assimilation during leaf and berry development of Vitis vinifera

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    The changes in the activities of 0-acetylserine sulphydrylase, ATP sulphurylase, glutamate dehydrogenase, glutamine synthetase and nitrate reductase in extracts from leaves and berries of Vitis vinifera L. cv. Merlot were studied at weekly intervals prior to anthesis up to grape harvest. Total nitrogen, amino nitrogen and protein contents were also determined.The total nitrogen content decreased from the beginning of the determinations either in leaves or in berries. Protein and amino nitrogen increments in berries matched their decreases in leaves.Nitrate reductase activity was not detectable either in leaves or berries. On the contrary, all the other examined enzymes showed at least three maxima of activity: one at anthesis and the others between the beginning of berry development and grape harvest.The ATP sulphurylase, 0-acetylserine sulphydrylase and glutamate dehydrogenase activities of berries were always higher than those observed in leaves, whereas glutamine synthetase activitywas similar in the two organs.Our results indicate that sulphur and nitrogen assimilation occur either in leavesor berries of grapevine.Changements des activités enzymatiques de l'assimilation de l'azote et du soufre pendant le développement de la feuille et du grain de Vitis viniferaSur des extraits de feuilles et de grains de raisins de Vitis vinifera L. cv. Merlot, prélevés chaque semaine dans la période entre la floraison et la vendange, les changements des activités enzymatiques de 1'0-acétylsérine sulfhydrilase, ATP sulfurylase, glutamate déshydrogénase, glutamine synthétase et de la nitrate réductase ont été étudiés.La teneur en azote total diminuait dans les feuilles aussi bien que dans les grains. L'accroissement des protéines et de l'amino-azote dans les grains était lié à leur décroissement dans les feuilles. L'activité enzymatique de la nitrate réductase n'a été retrouvée ni dans les grains ni dans les feuilles; toutes les autres activités enzymatiques analysées présentaient au moins trois pointes d'activités: la premiÚre à la floraison, les autres dans la période comprise entre le début du développement du grain et la vendange.Les activités de l'ATP sulfurylase, 0-acétylsérine sulfhydrilase et de la glutamate déshydrogénase étaient plus élevées dans les grains que dans les feuilles, tandis que l'activité de la glutamine synthétase était pareille dans les deux organes.Ces résultas indiquent que l'assimilation du soufre et de l'azote se fait dans les feuilles aussi bien que dans les grains de la vigne

    A finite element flux-corrected transport method for wave propagation in heterogeneous solids

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    When moving discontinuities in solids need to be simulated, standard finite element (FE) procedures usually attain low accuracy because of spurious oscillations appearing behind the discontinuity fronts. To assure an accurate tracking of traveling stress waves in heterogeneous media, we propose here a flux-corrected transport (FCT) technique for structured as well as unstructured space discretizations. The FCT technique consists of post-processing the FE velocity field via diffusive/antidiffusive fluxes, which rely upon an algorithmic length-scale parameter. To study the behavior of heterogeneous bodies featuring compliant interphases of any shape, a general scheme for computing diffusive/antidiffusive fluxes close to phase boundaries is proposed too. The performance of the new FE-FCT method is assessed through one-dimensional and two-dimensional simulations of dilatational stress waves propagating along homogeneous and composite rods

    Global well-posedness of the Kirchhoff equation and Kirchhoff systems

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    This article is devoted to review the known results on global well-posedness for the Cauchy problem to the Kirchhoff equation and Kirchhoff systems with small data. Similar results will be obtained for the initial-boundary value problems in exterior domains with compact boundary. Also, the known results on large data problems will be reviewed together with open problems.Comment: arXiv admin note: text overlap with arXiv:1211.300

    Reduction of environmental impacts due to using permeable pavements to harvest stormwater

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    While rainwater harvesting can provide additional water resources, this approach is largely undertaken using water from roofs. More recently, the potential for using stormwater harvested from permeable pavements was recognised as a potential additional water resource. The objective of this study was to estimate the reduction of environmental impacts caused by traditional drainage systems and centralised water utilities if permeable pavement systems were used to harvest stormwater for nonpotable purposes in buildings. The lifecycle environmental impacts and costs associated with the proposed pavements and hydraulic systems were assessed. The city of Glasgow was chosen as a case study. We used the Netuno computer programme to estimate the potential for potable water savings considering the use of stormwater for nonpotable purposes and the SimaPro software to perform a lifecycle assessment (LCA). With the implementation of permeable pavements and stormwater utilisation, great reductions in lifecycle emissions (i.e., CO2-, SO2-, and PM2.5-equivalent emissions) were observed. The proposed system also proved to be economically feasible, i.e., a payback period equal to 16.9 years. The results show the economic and environmental feasibility of permeable pavements when used on a large scale, proving to be an important strategy to reduce water and environmental stresses caused by centralised water utilities and traditional drainage systems

    Validation of the 8-item Attitudes Towards Gambling Scale (ATGS-8) in a British population survey

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    Introduction. Public opinions concerning gambling are an important factor in shaping public policy. Little empirical attention has been given to assessing gambling attitudes within the general population. The aim of the present study is to validate the 8-item Attitudes Towards Gambling Scale (ATGS-8) in British individuals and to investigate associations of these attitudes with frequency of gambling and gambling problems. Methods. Data were derived from 7746 individuals participating in the British Gambling Prevalence Survey 2010, a comprehensive interview-based survey conducted in Great Britain between November 2009 and May 2010. Confirmatory factor analysis and separate regression analyses were applied. Results. The one-dimensional structure of the ATGS-8 was confirmed in the community sample and by gender. Furthermore, more positive attitudes towards gambling were positively related to frequency of gambling and gambling problems. Conclusions. The present study extends the previous evaluations of the scale by providing detailed evidence for the utility and usefulness of the ATGS-8 in a community sample and across gender. The ATGS-8 is a valid instrument to assess public opinion on gambling among the general population

    Social prescribing in cardiology : rediscovering the nature of and within us

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    Personalised care is integral to the delivery of the NHSE Long Term Plan. Enabling choice and supporting patients to make decisions predicated on what matters to them, rather than what is the matter with them, is a fundamental part of the NHS vision. Social prescribing uses nonmedical, asset based, salutogenic approaches to promote this personalised paradigm, and places the patient central to decision making. We discuss how Personalised care can be used to help people with Cardiovascular Disease (CVD) using socially prescribed ‘nature-based’ interventions to support the prehabilitation and rehabilitation of patients with CVD. The concept of Personalised care outlined and the significance of salutogenic principles as complementary approach to the pathogenic model is discussed. We argue that this seemingly novel approach to using nature-based interventions can help promote wellbeing for people with CVD as part of the wider personalised agenda

    A regularity class for the roots of nonnegative functions

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    We investigate the regularity of the positive roots of a non-negative function of one-variable. A modified H\"older space FÎČ\mathcal{F}^\beta is introduced such that if f∈FÎČf\in \mathcal{F}^\beta then fα∈CαÎČf^\alpha \in C^{\alpha \beta}. This provides sufficient conditions to overcome the usual limitation in the square root case (α=1/2\alpha = 1/2) for H\"older functions that f1/2f^{1/2} need be no more than C1C^1 in general. We also derive bounds on the wavelet coefficients of fαf^\alpha, which provide a finer understanding of its local regularity.Comment: 12 page

    Notch signaling during human T cell development

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    Notch signaling is critical during multiple stages of T cell development in both mouse and human. Evidence has emerged in recent years that this pathway might regulate T-lineage differentiation differently between both species. Here, we review our current understanding of how Notch signaling is activated and used during human T cell development. First, we set the stage by describing the developmental steps that make up human T cell development before describing the expression profiles of Notch receptors, ligands, and target genes during this process. To delineate stage-specific roles for Notch signaling during human T cell development, we subsequently try to interpret the functional Notch studies that have been performed in light of these expression profiles and compare this to its suggested role in the mouse

    Financial feasibility of end-user designed rainwater harvesting and greywater reuse systems for high water use households

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    © 2017, The Author(s). Water availability pressures, competing end-uses and sewers at capacity are all drivers for change in urban water management. Rainwater harvesting (RWH) and greywater reuse (GWR) systems constitute alternatives to reduce drinking water usage and in the case of RWH, reduce roof runoff entering sewers. Despite the increasing popularity of installations in commercial buildings, RWH and GWR technologies at a household scale have proved less popular, across a range of global contexts. For systems designed from the top-down, this is often due to the lack of a favourable cost-benefit (where subsidies are unavailable), though few studies have focused on performing full capital and operational financial assessments, particularly in high water consumption households. Using a bottom-up design approach, based on a questionnaire survey with 35 households in a residential complex in Bucaramanga, Colombia, this article considers the initial financial feasibility of three RWH and GWR system configurations proposed for high water using households (equivalent to >203L per capita per day). A full capital and operational financial assessment was performed at a more detailed level for the most viable design using historic rainfall data. For the selected configuration (‘Alt 2’), the estimated potable water saving was 44% (equivalent to 131m3/year) with a rate of return on investment of 6.5% and an estimated payback period of 23years. As an initial end-user-driven design exercise, these results are promising and constitute a starting point for facilitating such approaches to urban water management at the household scale
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