855 resultados para dam impacts


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The objective of this work was to evaluate the effect of the temperature increase forecasted by the Intergovernmental Panel on Climate Change (IPCC) on agricultural zoning of cotton production in Brazil. The Northeastern region showed the highest decrease in the low-risk area for cotton cultivation due to the projected temperature increase. This area in the Brazilian Northeast may decrease from 83 million ha in 2010 to approximately 71 million ha in 2040, which means 15% reduction in 30 years. Southeastern and Center-Western regions had small decrease in areas suitable for cotton production until 2040, while the Northern region showed no reduction in these areas. Temperature increase will not benefit cotton cultivation in Brazil because dimension of low-risk areas for economic cotton production may decrease.

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Accurate perception of the temporal order of sensory events is a prerequisite in numerous functions ranging from language comprehension to motor coordination. We investigated the spatio-temporal brain dynamics of auditory temporal order judgment (aTOJ) using electrical neuroimaging analyses of auditory evoked potentials (AEPs) recorded while participants completed a near-threshold task requiring spatial discrimination of left-right and right-left sound sequences. AEPs to sound pairs modulated topographically as a function of aTOJ accuracy over the 39-77ms post-stimulus period, indicating the engagement of distinct configurations of brain networks during early auditory processing stages. Source estimations revealed that accurate and inaccurate performance were linked to bilateral posterior sylvian regions activity (PSR). However, activity within left, but not right, PSR predicted behavioral performance suggesting that left PSR activity during early encoding phases of pairs of auditory spatial stimuli appears critical for the perception of their order of occurrence. Correlation analyses of source estimations further revealed that activity between left and right PSR was significantly correlated in the inaccurate but not accurate condition, indicating that aTOJ accuracy depends on the functional decoupling between homotopic PSR areas. These results support a model of temporal order processing wherein behaviorally relevant temporal information--i.e. a temporal 'stamp'--is extracted within the early stages of cortical processes within left PSR but critically modulated by inputs from right PSR. We discuss our results with regard to current models of temporal of temporal order processing, namely gating and latency mechanisms.

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Shallow upland drains, grips, have been hypothesized as responsible for increased downstream flow magnitudes. Observations provide counterfactual evidence, often relating to the difficulty of inferring conclusions from statistical correlation and paired catchment comparisons, and the complexity of designing field experiments to test grip impacts at the catchment scale. Drainage should provide drier antecedent moisture conditions, providing more storage at the start of an event; however, grips have higher flow velocities than overland flow, thus potentially delivering flow more rapidly to the drainage network. We develop and apply a model for assessing the impacts of grips on flow hydrographs. The model was calibrated on the gripped case, and then the gripped case was compared with the intact case by removing all grips. This comparison showed that even given parameter uncertainty, the intact case had significantly higher flood peaks and lower baseflows, mirroring field observations of the hydrological response of intact peat. The simulations suggest that this is because delivery effects may not translate into catchment-scale impacts for three reasons. First, in our case, the proportions of flow path lengths that were hillslope were not changed significantly by gripping. Second, the structure of the grip network as compared with the structure of the drainage basin mitigated against grip-related increases in the concentration of runoff in the drainage network, although it did marginally reduce the mean timing of that concentration at the catchment outlet. Third, the effect of the latter upon downstream flow magnitudes can only be assessed by reference to the peak timing of other tributary basins, emphasizing that drain effects are both relative and scale dependent. However, given the importance of hillslope flow paths, we show that if upland drainage causes significant changes in surface roughness on hillslopes, then critical and important feedbacks may impact upon the speed of hydrological response. Copyright (c) 2012 John Wiley & Sons, Ltd.

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L'évolution de l'environnement économique, des chaînes de valeur et des modèles d'affaires des organisations augmentent l'importance de la coordination, qui peut être définie comme la gestion des interdépendances entre des tâches réalisées par des acteurs différents et concourants à un objectif commun. De nombreux moyens sont mis en oeuvre au sein des organisations pour gérer ces interdépendances. A cet égard, les activités de coordination bénéficient massivement de l'appui des technologies de l'information et de communication (TIC) qui sont désormais disséminées, intégrées et connectées sous de multiples formes tant dans l'environnement privé que professionnel. Dans ce travail, nous avons investigué la question de recherche suivante : comment l'ubiquité et l'interconnec- tivité des TIC modifient-elles les modes de coordination ? A travers quatre études en systèmes d'information conduites selon une méthodologie design science, nous avons traité cette question à deux niveaux : celui de l'alignement stratégique entre les affaires et les systèmes d'information, où la coordination porte sur les interdépendances entre les activités ; et celui de la réalisation des activités, où la coordination porte sur les interdépendances des interactions individuelles. Au niveau stratégique, nous observons que l'ubiquité et l'interconnectivité permettent de transposer des mécanismes de coordination d'un domaine à un autre. En facilitant différentes formes de coprésence et de visibilité, elles augmentent aussi la proximité dans les situations de coordination asynchrone ou distante. Au niveau des activités, les TIC présentent un très fort potentiel de participation et de proximité pour les acteurs. De telles technologies leur donnent la possibilité d'établir les responsabilités, d'améliorer leur compréhension commune et de prévoir le déroulement et l'intégration des tâches. La contribution principale qui émerge de ces quatre études est que les praticiens peuvent utiliser l'ubiquité et l'interconnectivité des TIC pour permettre aux individus de communi-quer et d'ajuster leurs actions pour définir, atteindre et redéfinir les objectifs du travail commun. -- The evolution of the economic environment and of the value chains and business models of organizations increases the importance of coordination, which can be defined as the management of interdependences between tasks carried out by different actors and con-tributing to a common goal. In organizations, a considerable number of means are put into action in order to manage such interdependencies. In this regard, information and communication technologies (ICT), whose various forms are nowadays disseminated, integrated and connected in both private and professional environments, offer important support to coordination activities. In this work, we have investigated the following research question: how do the ubiquity and the interconnectivity of ICT modify coordination mechanisms? Throughout four information systems studies conducted according to a design science methodology, we have looked into this question at two different levels: the one of strategic alignment between business and information systems strategy, where coordination is about interdependencies between activities; and the one of tasks, where coordination is about interdependencies between individual interactions. At the strategic level, we observe that ubiquity and interconnectivity allow for transposing coordination mechanisms from one field to another. By facilitating various forms of copresence and visibility, they also increase proximity in asynchronous or distant coordination situations. At the tasks level, ICTs offer the actors a very high potential for participation and proximity. Such technologies make it possible to establish accountability, improve common understanding and anticipate the unfolding and integration of tasks. The main contribution emerging from these four studies is that practitioners can use the ubiquity and interconnectivity of ICT in order to allow individuals to communicate and adjust their actions to define, reach and redefine the goals of common work.

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Ihmisen toiminnan vaikutus ilmakehään johtaa todennäköisesti ilmastonmuutoksiin. Eräs näistä muutoksista on maapallon keskilämpötilan nousu, joka aiheutuu kasvihuonekaasujen lisääntyneestä pitoisuudesta ilmakehässä. Vaikutusten vähentämiseksi on hiilidioksidipäästöjä vähennettävä. Kioton pöytäkirja asettaa allekirjoittaneille maille päästövelvoitteet. Euroopan unionin tulee vähentää kasvihuonekaasupäästöjään 8%:lla. Eräs vähennysmekanismeista on päästökauppa. Päästökauppa on sekä keino suojella ympäristöä että ympäristöpoliittinen instrumentti kasvihuonekaasupäästövähennysten kustannusten keventämiseksi. Päästökauppa ei suoranaisesti vähennä kasvihuonekaasupäästöjä, vaan tasaa niitä maiden ja laitosten välillä. Uusiutuvan energian käytön edistäminen sekä kansainvälisesti että kansallisesti johtaa suoriin kasvihuonekaasupäästöjen vähenemiseen. Euroopan unionin jäsenvaltiot ovat asettaneet kansalliset viitearvot uusituvan sähkön kulutukselle. Saavuttaakseen nämä viitearvot maiden tulee tukea uusiutuvia energialähteitä eri menetelmin kuten vihreillä sertifikaateilla. Päästökauppa ja kaupattavat vihreät sertifikaatit tulevat vaikuttamaan energiantuottajien liiketoimintaan. Työssä on tutkittu päästökaupan ja vihreiden sertifikaattien vaikutuksia Vattenfall Kaukolämpö Oy:n, Vattenfall Sähköntuotanto Oy:n ja Vamy Oy:n liiketoimintaan.

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This study presents an innovative pedagogical approach where teachers become game designers and engage in creative teaching practices. Within co-design training workshops, 21 Spanish primary and secondary school teachers have developed their own Game-Based Learning (GBL) scenarios, especially tailored to their teaching contexts and students profiles. In total, teachers developed 13 GBL scenarios and put them into practice in real teaching contexts. The present paper analyses the impacts of this learner-centred game design approach on teachers" creativity from three different points of view: the GBL design process, the GBL scenario, and the teaching processes at stake.

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This paper investigates the impacts of globalization processes on the Swiss business elite community during the 1980-2010 period. Switzerland has been characterized in the 20th century by its extraordinary stability and by the strong cohesion of its elite community. To study recent changes, we focus on Switzerland's 110 largest firms' by adopting a diachronic perspective based on three elite cohorts (1980, 2000, and 2010). An analysis of interlocking directorates allows us to describe the decline of the Swiss corporate network. The second analysis focuses on top managers' profiles in terms of education, nationality as well as participation in national community networks that used to reinforce the cultural cohesion of the Swiss elite community, especially the militia army. Our results highlight a slow but profound transformation of top management profiles, characterized by a decline of traditional national elements of legitimacy and the emergence of new "global" elements. The diachronic and combined analysis brings into light the strong cultural changes experienced by the national business elite community.

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Freshwater ecosystems and their biodiversity are presently seriously threatened by global development and population growth, leading to increases in nutrient inputs and intensification of eutrophication-induced problems in receiving fresh waters, particularly in lakes. Climate change constitutes another threat exacerbating the symptoms of eutrophication and species migration and loss. Unequivocal evidence of climate change impacts is still highly fragmented despite the intensive research, in part due to the variety and uncertainty of climate models and underlying emission scenarios but also due to the different approaches applied to study its effects. We first describe the strengths and weaknesses of the multi-faceted approaches that are presently available for elucidating the effects of climate change in lakes, including space-for-time substitution, time series, experiments, palaeoecology and modelling. Reviewing combined results from studies based on the various approaches, we describe the likely effects of climate changes on biological communities, trophic dynamics and the ecological state of lakes. We further discuss potential mitigation and adaptation measures to counteract the effects of climate change on lakes and, finally, we highlight some of the future challenges that we face to improve our capacity for successful prediction.

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Mountain regions worldwide are particularly sensitive to on-going climate change. Specifically in the Alps in Switzerland, the temperature has increased twice as fast than in the rest of the Northern hemisphere. Water temperature closely follows the annual air temperature cycle, severely impacting streams and freshwater ecosystems. In the last 20 years, brown trout (Salmo trutta L) catch has declined by approximately 40-50% in many rivers in Switzerland. Increasing water temperature has been suggested as one of the most likely cause of this decline. Temperature has a direct effect on trout population dynamics through developmental and disease control but can also indirectly impact dynamics via food-web interactions such as resource availability. We developed a spatially explicit modelling framework that allows spatial and temporal projections of trout biomass using the Aare river catchment as a model system, in order to assess the spatial and seasonal patterns of trout biomass variation. Given that biomass has a seasonal variation depending on trout life history stage, we developed seasonal biomass variation models for three periods of the year (Autumn-Winter, Spring and Summer). Because stream water temperature is a critical parameter for brown trout development, we first calibrated a model to predict water temperature as a function of air temperature to be able to further apply climate change scenarios. We then built a model of trout biomass variation by linking water temperature to trout biomass measurements collected by electro-fishing in 21 stations from 2009 to 2011. The different modelling components of our framework had overall a good predictive ability and we could show a seasonal effect of water temperature affecting trout biomass variation. Our statistical framework uses a minimum set of input variables that make it easily transferable to other study areas or fish species but could be improved by including effects of the biotic environment and the evolution of demographical parameters over time. However, our framework still remains informative to spatially highlight where potential changes of water temperature could affect trout biomass. (C) 2015 Elsevier B.V. All rights reserved.-