1,565 research outputs found

    Participatory analysis for adaptation to climate change in Mediterranean agricultural systems: possible choices in process design (versão Pre Print)

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    There is an increasing call for local measures to adapt to climate change, based on foresight analyses in collaboration with actors. However, such analyses involve many challenges, particularly because the actors concerned may not consider climate change to be an urgent concern. This paper examines the methodological choices made by three research teams in the design and implementation of participatory foresight analyses to explore agricultural and water management options for adaptation to climate change. Case studies were conducted in coastal areas of France, Morocco, and Portugal where the groundwater is intensively used for irrigation, the aquifers are at risk or are currently overexploited, and a serious agricultural crisis is underway. When designing the participatory processes, the researchers had to address four main issues: whether to avoid or prepare dialogue between actors whose relations may be limited or tense; how to select participants and get them involved; how to facilitate discussion of issues that the actors may not initially consider to be of great concern; and finally, how to design and use scenarios. In each case, most of the invited actors responded and met to discuss and evaluate a series of scenarios. Strategies were discussed at different levels, from farming practices to aquifer management. It was shown that such participatory analyses can be implemented in situations which may initially appear to be unfavourable. This was made possible by the flexibility in the methodological choices, in particular the possibility of framing the climate change issue in a broader agenda for discussion with the actors

    Actividad glutatión peroxidasa en vacas lecheras sin suplementar y suplementadas con selenio

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    The aim of this work was to evaluate glutathione peroxidase (GPX) activity levels in dairy cows supplemented and not supplemented with intra-ruminal selenium (Se) boluses. The GPX activity of 96 clinically healthy primiparous and multiparous Holstein dairy cows, from a commercial establishment in Centeno´s town, Santa Fe Province (Argentina), was assessed. According to the individual GPX determinations, two categories of cows were defined taking 130 U/gHb as the cut value. The cows in each category were randomly divided in two subgroups, one of which received an intra-ruminal bolus of long-acting Se (Permatrace®) while the other remained unsupplemented. Next, two new enzymatic activity determinations were made: ante-partum (between 30 and 15 days before calving) and post-partum (between 30 and 45 after calving). The 35.4% of the cows presented enzyme activity values lower than the cut value. Cows with low basal values of GPX activity not supplemented with Se boluses did not significantly modify the basal values. In cows with low basal values of GPX activity and supplemented with Se, a significant increase in enzymatic activity was observed. It is concluded that a significant proportion of cows have low GPX activity, enzymatic activity levels are modified according to the moment of evaluation in relation to calving and that supplementation with intra-ruminal Se is an effective strategy to increase the enzyme activity.El objetivo del presente trabajo fue evaluar los niveles de la actividad glutatión-peroxidasa(GPX) en vacas lecheras suplementadas y sin suplementar con selenio (Se) intra-ruminal.Se determinó la actividad GPX de 96 vacas Holstein primíparas y multíparas, clínicamentesanas, procedentes de un establecimiento comercial de la localidad de Centeno, Provincia deSanta Fe (Argentina). Se definieron dos categorías de reses según las determinaciones individuales de GPX tomando como valor de corte 130 U/gHb. Los animales de cada categoría se dividieron aleatoriamente en dos subgrupos, uno de los cuales recibió un bolo intraruminalde Se de larga acción (Permatrace®) mientras que el otro permaneció sin suplementar. Acontinuación, se efectuaron dos nuevas determinaciones de la actividad enzimática: preparto(entre los 30 y los 15 días previos al parto) y posparto (entre los 30 y los 45 posteriores alparto). El 35,4% de las vacas presentó valores de actividad de la enzima menores al valor decorte. Los animales con bajos valores basales de actividad GPX no suplementadas con bolosde Se, no modificaron significativamente los datos basales. En las vacas con bajos valoresbasales de actividad GPX y suplementadas con Se, se observó un aumento significativo de laactividad enzimática. Se concluye que una proporción importante de animales presenta bajaactividad GPX, que los niveles de las enzimas se modifican según el momento de la evaluaciónen relación al tiempo del parto, y que la suplementación con bolos de Se intra-ruminalconstituye una estrategia efectiva para aumentar la actividad de la enzima

    Spatial mapping of flow-induced molecular alignment in a noncrystalline biopolymer fluid using double quantum filtered (DQF) 23Na MRI

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    Flow-induced molecular alignment was observed experimentally in a non-liquid- crystalline bioplymeric fluid during developed tubular flow. The fluid was comprised of rigid rods of the polysaccharide xanthan and exhibited shear-thinning behavior. Without a requirement for optical transparency or the need for an added tracer, 23Na magic angle (MA) double quantum filtered (DQF) magnetic resonance imaging (MRI) enabled the mapping of the anisotropic molecular arrangement under flow conditions. A regional net molecular alignment was found in areas of high shear values in the vicinity of the tube wall. Furthermore, the xanthan molecules resumed random orientations after the cessation of flow. The observed flow-induced molecular alignment was correlated with the rheological properties of the fluid. The work demonstrates the ability of 23Na MA DQF magnetic resonance to provide a valuable molecular-mechanical link

    Inter-basin transfers as a supply option: the end of an era?

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    International audienceThis chapter discusses the evolving role of interbasin transfers (IBT) in urban water management. After providing an historical overview of IBT development, the chapter describes how IBTs are challenged by a change in the technological and socio-economic context. The emergence of alternative technologies, such as desalination, wastewater reclamation and reuse, or managed artificial groundwater recharge is reducing the attractiveness of IBTs. Water utilities are also becoming increasingly aware that water conservation programs can save volumes of water at a much cheaper cost than IBT. Various international examples are used to show that IBTs trigger increasing concerns from communities involved or affected, in particular related to the environmental impact on donor and receiving river basins, the economic impact on donor regions, the impact on local cultures and livelihoods, how costs and benefits are distributed (social justice), and issues related to public participation. The chapter concludes by looking ahead at new and more efficient uses of existing IBTs. As conjunctive use management approaches gain support, IBTs will be operated in conjunction with aquifer storage and recovery schemes. They will probably also support the development of emerging water markets, in particular during drought years

    Search for charginos in e+e- interactions at sqrt(s) = 189 GeV

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    An update of the searches for charginos and gravitinos is presented, based on a data sample corresponding to the 158 pb^{-1} recorded by the DELPHI detector in 1998, at a centre-of-mass energy of 189 GeV. No evidence for a signal was found. The lower mass limits are 4-5 GeV/c^2 higher than those obtained at a centre-of-mass energy of 183 GeV. The (\mu,M_2) MSSM domain excluded by combining the chargino searches with neutralino searches at the Z resonance implies a limit on the mass of the lightest neutralino which, for a heavy sneutrino, is constrained to be above 31.0 GeV/c^2 for tan(beta) \geq 1.Comment: 22 pages, 8 figure

    Hadronization properties of b quarks compared to light quarks in e+e- -> q qbar from 183 to 200 GeV

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    The DELPHI detector at LEP has collected 54 pb^{-1} of data at a centre-of-mass energy around 183 GeV during 1997, 158 pb^{-1} around 189 GeV during 1998, and 187 pb^{-1} between 192 and 200 GeV during 1999. These data were used to measure the average charged particle multiplicity in e+e- -> b bbar events, _{bb}, and the difference delta_{bl} between _{bb} and the multiplicity, _{ll}, in generic light quark (u,d,s) events: delta_{bl}(183 GeV) = 4.55 +/- 1.31 (stat) +/- 0.73 (syst) delta_{bl}(189 GeV) = 4.43 +/- 0.85 (stat) +/- 0.61 (syst) delta_{bl}(200 GeV) = 3.39 +/- 0.89 (stat) +/- 1.01 (syst). This result is consistent with QCD predictions, while it is inconsistent with calculations assuming that the multiplicity accompanying the decay of a heavy quark is independent of the mass of the quark itself.Comment: 13 pages, 2 figure

    Search for composite and exotic fermions at LEP 2

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    A search for unstable heavy fermions with the DELPHI detector at LEP is reported. Sequential and non-canonical leptons, as well as excited leptons and quarks, are considered. The data analysed correspond to an integrated luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172 GeV and 161 GeV. The search for pair-produced new leptons establishes 95% confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2, depending on the channel. The search for singly produced excited leptons and quarks establishes upper limits on the ratio of the coupling of the excited fermio

    Search for supersymmetric particles in scenarios with a gravitino LSP and stau NLSP

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    Sleptons, neutralinos and charginos were searched for in the context of scenarios where the lightest supersymmetric particle is the gravitino. It was assumed that the stau is the next-to-lightest supersymmetric particle. Data collected with the DELPHI detector at a centre-of-mass energy near 189 GeV were analysed combining the methods developed in previous searches at lower energies. No evidence for the production of these supersymmetric particles was found. Hence, limits were derived at 95% confidence level.Comment: 31 pages, 14 figure
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