Água e mudanças climáticas

This study constitutes a review of the state-of-the-art on knowledge about climate change and water in Brazil and South America. We discuss some of the results of the studies by the Intergovernmental Panel on Climate Change (IPCC) and the Inpe's Climate Report on observational studies of climate variability and future projections of change in climate and on the components of the hydrological cycle, until the end of the XXI Century, for the major basins in the continent. One of the main aspects of this document is on the economical and management aspects of water resources in different regions of Brazil, and how that may change in a climate change scenario.O presente documento constitui uma revisão do estado da arte do conhecimento sobre mudanças de clima e água no Brasil e na América do Sul. Discutem-se alguns dos resultados dos estudos do Painel Intergovernamental de Mudanças Climáticas (IPCC) e do Relatório de Clima do Inpe em relação a estudos obervacionais de variabilidade de clima e projeções de clima e das componentes do ciclo hidrológico até finais do século XXI, para as principais bacias hidrográficas no continente. Um dos aspectos importantes discutidos neste informe refere-se aos aspectos econômico e gerencial do recurso água nas diferentes regiões do Brasil, e como isso pode mudar num cenário de mudanças de clima

La organización fuera de control

El objetivo general de este trabajo de investigación será relacionar los modelos de las configuraciones básicas de Henry Mintzberg (1991) con diversos funcionamientos afines a estructuras mentales, y donde generamos las siguientes hipótesis de trabajo: Si la cumbre estratégica está fuera de control, podremos predecir un funcionamiento organizacional histérico. Si la está tecnoestructura está fuera de control, podremos predecir un funcionamiento organizacional obsesivo. Si la línea media está fuera de control, podremos predecir un funcionamiento organizacional depresivo. Si el núcleo operativo está fuera de control, podremos predecir un funcionamiento organizacional paranoide. Si el staff de apoyo está fuera de control, podremos predecir un funcionamiento organizacional esquizoide. La metodología utilizada para esta investigación se basó en el relevamiento de diversas fuentes de información, principalmente de autores que han desarrollado algunos conceptos de psicología organizacional tales como Danny Miller y Ketz de Vries (1984), y han sido incorporados al funcionamiento organizacional de Mintzberg (1991); teorizando fallas paramétricas de diseño que llevasen a “funcionamientos" mentales específicos a los diferentes tipos de configuraciones organizacionalesFil: Marengo, José Alberto. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas

O futuro clima do Brasil

Eventos climáticos extremos recentes, como as enchentes na Bacia do Rio Madeira em 2014 e as secas atuais no Nordeste e no Sudeste do Brasil, e os seus impactos na segurança energética, hídrica e alimentar mostram que o Brasil é vulnerável aos extremos da variabilidade de clima. Como esses extremos são associados à variabilidade natural do clima, existem evidências de que eles seriam mais intensos e frequentes num futuro clima mais quente, e de que as atividades antrópicas podem também ter uma participação significativa no processo de aquecimento global.Recent extreme climate events such as the Rio Madeira flooding in 2014 and the current drought in Northeastern and in Southeastern Brazil, and their impacts on energy, food and water security, show that Brazil is vulnerable to extremes in climate variability. As these extremes are associated with natural climate variability, there are evidences that they would be more intense and frequent in a warmer future climate, and that human activities can also have a significant role in this process of global warming

Sustained exocytosis after action potential-like stimulation at low frequencies in mouse chromaffin cells depends on a dynamin-dependent fast endocytotic process

Under basal conditions the action potential firing rate of adrenal chromaffin cells is lower than 0.5 Hz. The maintenance of the secretory response at such frequencies requires a continuous replenishment of releasable vesicles. However, the mechanism that allows such vesicle replenishment remains unclear. Here, using membrane capacitance measurements on mouse chromaffin cells, we studied the mechanism of replenishment of a group of vesicles released by a single action potential-like stimulus (APls). The exocytosis triggered by APls (ETAP) represents a fraction (40%) of the immediately releasable pool, a group of vesicles highly coupled to voltage dependent calcium channels. ETAP was replenished with a time constant of 0.73 � 0.11 s, fast enough to maintain synchronous exocytosis at 0.2-0.5 Hz stimulation. Regarding the mechanism involved in rapid ETAP replenishment, we found that it depends on the ready releasable pool; indeed depletion of this vesicle pool significantly delays ETAP replenishment. On the other hand, ETAP replenishment also correlates with a dynamin-dependent fast endocytosis process (τ = 0.53 � 0.01 s). In this regard, disruption of dynamin function markedly inhibits the fast endocytosis and delays ETAP replenishment, but also significantly decreases the synchronous exocytosis during repetitive APls stimulation at low frequencies (0.2 and 0.5 Hz). Considering these findings, we propose a model in where both the transfer of vesicles from ready releasable pool and fast endocytosis allow rapid ETAP replenishment during low stimulation frequencies.Fil: Moya Diaz, José Abelino. Universidad de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Ecología, Genética y Evolución. Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Alvarez, Yanina Daniela. Universidad de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Ecología, Genética y Evolución. Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Montenegro, Mauricio Norman. Universidad de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Ecología, Genética y Evolución. Buenos Aires; ArgentinaFil: Bayonés, Lucas. Universidad de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Ecología, Genética y Evolución. Buenos Aires; ArgentinaFil: Belingheri, Ana Verónica. Universidad de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Ecología, Genética y Evolución. Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: González-Jamett, Arlek M.. Universidad de Valparaiso; ChileFil: Cárdenas, Ana M.. Universidad de Valparaiso; ChileFil: Marengo, Fernando Diego. Universidad de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Ecología, Genética y Evolución. Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin

Late Pleistocene-Holocene History of Chaco-Pampa Sediments in Argentina and Paraguay

Eine erheblich verbesserte Rekonstruktion der spätpleistozänen/holozänen morphologischen und geologischen Geschichte des paraguayischen Chaco und der argentinischen Pampa Ebene wird vorgestellt. Wegen der großen Ausdehnung des Gebietes waren Satellitenbilder der Schlüssel, um frühere und neue interdisziplinäre geowissenschaftliche Ergebnisse zu einem verlässlicheren Bild zusammenzuführen. Für diesen synoptischen Überblick wurde die Interpretation von Fernerkundungsdaten durch Geländeuntersuchungen und physikalische Altersbestimmungen ergänzt. Viele Lumineszenzalter (75 IRSL und 12 TL) von Löß, lößähnlichen Sedimenten und Sanden wurden bestimmt, die bei der Rekonstruktion der Klimageschichte des Untersuchungsgebiets im Marinen Isotopen Stadium 3 bis 1 (MIS 3–1) beitragen. Lößablagerungen überwiegen in der Zeit vor MIS 2. Die numerische Alter von lakustrinen und alluvialen Sedimenten, im Löß zwischengelagert, belegen wechselnde feuchte und trockene Perioden in der Chaco/Pampa-Ebene im MIS 2 und MIS 1. Überwiegend trockene Bedingungen herrschten von 8.5 bis 3.5 ka BP (mittleres MIS 1), als Sande in Form von Dünen oder in Paläoflussbetten abgelagert wurden. Zeitlich begrenzte Phasen extrem verstärkter Paläoflussaktivität im Mittelholozän wurden auf sporadische Starkregenereignisse in den Anden zurückgeführt. Die Ursprungsgebiete des Löß, der lößartigen Sedimente und der sandigen Ablagerungen wurden in der südwestlichen Pampa, den benachbarten Andenabhängen und im Altiplano lokalisiert. Diese Sedimente wurden von dort nach Osten und später nach Nordosten transportiert, wie sich aus den morphologischen Mustern als Zeugnisse früherer äolischer Aktivität rekonstruieren ließ.researc

Impacts, vulnerability and adaptation to climate change in Brazil: an integrated approach

Impacts, vulnerability and adaptation to climate change in Brazil: an integrated approachImpacts, vulnerability and adaptation to climate change in Brazil: an integrated approac

Onset and End of the Rainy Season in South America in Observations and the ECHAM 4.5 Atmospheric General Circulation Model

Rainfall in South America as simulated by a 24-ensemble member of the ECHAM 4.5 atmospheric general circulation model is compared and contrasted with observations (in areas in which data are available) for the period 1976–2001. Emphasis is placed on determining the onset and end of the rainy season, from which its length and rain rate are determined. It is shown that over large parts of the domain the onset and ending dates are well simulated by the model, with biases of less than 10 days. There is a tendency for model onset to occur early and ending to occur late, resulting in a simulated rainy season that is on average too long in many areas. The model wet season rain rate also tends to be larger than observed. To estimate the relative importance of errors in wet season length and rain rate in determining biases in the annual total, adjusted totals are computed by substituting both the observed climatological wet season length and rate for those of the model. Problems in the rain rate generally are more important than problems in the length. The wet season length and rain rate also contribute substantially to interannual variations in the annual total. These quantities are almost independent, and it is argued that they are each associated with different mechanisms. The observed onset dates almost always lie within the range of onset of the ensemble members, even in the areas with a large model onset bias. In some areas, though, the model does not perform well. In southern Brazil the model ensemble average onset always occurs in summer, whereas the observations show that winter is often the wettest period. Individual members, however, do occasionally show a winter rainfall peak. In southern Northeast Brazil the model has a more distinct rainy season than is observed. In the northwest Amazon the model annual cycle is shifted relative to that observed, resulting in a model bias. No interannual relationship between model and observed onset dates is expected unless onset in the model and observations has a mutual relationship with SST anomalies. In part of the near-equatorial Amazon, there does exist an interannual relationship between onset dates. Previous studies have shown that in this area there is a relationship between SST anomalies and variations in seasonal total rainfall