Impacto do sedimento sobre o desenvolvimento do perifíton no Rio Taquari, Pantanal, MS.

As macrófitas aquáticas são muito abundantes em áreas alagadas como as do Pantanal, e fornecem um vasto substrato para a microbiota, em particular para a comunidade perifítica. Foi avaliado o efeito da deposição de sedimento sobre a comunidade perifítica ao longo de 40km do trecho final do rio Taquari, em 12 estações de amostragem, em setembro de 1998. Foram coletados pecíolos de Eichhornia azurea, raspados e filtrados para análise da biomassa perifítica (clorofila a e peso seco). Foram tomadas amostras de raízes, caules e folhas da macrófita para análise do sedimento aderido. E as características da água também foram estudadas. Do sedimento suspenso analisado, 55% foi depositado até a última estação, e 86% é de origem inorgânica. A transparência da água passou de 27cm a 50cm na última estação de coleta, próxima à foz. A biomassa ficoperifítica aumentou nas últimas estações, sugerindo que próximo da foz a fixação e desenvolvimento dos organismos, principalmente os autotróficos, é beneficiada pela diminuição acentuada do material inorgânico.bitstream/item/37415/1/BP37.pd

Application of the incremental volumetric remapping method in the simulation of multi-step deep drawing processes

Since sheet metal forming has a high percentage contribution in the overall design costs of a new car, this engineering area assisted in the last decades to considerable development efforts. The present challenge is to simulate all the production stages, from the initial blank sheet to the final part ready to assembly. On this particular issue of multi-step deep-drawing simulation, this work presents a new remapping method called Incremental Volumetric Remapping (IVR) developed to minimize the error that occurs, when performing the variable transfer operation between two different meshes. The IVR method is based in a volumetric approach where the calculus of the remapped state variables is obtained by means of a weighted average of the intersection volume between the meshes. The method performance is tested and compared with a standard extrapolation-interpolation, by applying a numerical example of the Numisheet'005 Conference, "The Channel Draw/Cylindrical Cup Benchmark".(undefined

The gathering firestorm in southern Amazonia.

Wildfires, exacerbated by extreme weather events and land use, threaten to change the Amazon from a net carbon sink to a net carbon source. Here, we develop and apply a coupled ecosystem-fire model to quantify how greenhouse gas-driven drying and warming would affect wildfires and associated CO2 emissions in the southern Brazilian Amazon. Regional climate projections suggest that Amazon fire regimes will intensify under both low- and high-emission scenarios. Our results indicate that projected climatic changes will double the area burned by wildfires, affecting up to 16% of the region's forests by 2050. Although these fires could emit as much as 17.0 Pg of CO2 equivalent to the atmosphere, avoiding new deforestation could cut total net fire emissions in half and help prevent fires from escaping into protected areas and indigenous lands. Aggressive efforts to eliminate ignition sources and suppress wildfires will be critical to conserve southern Amazon forests

Observing Grasping Actions Directed to Emotion-Laden Objects: Effects upon Corticospinal Excitability

The motor system is recruited whenever one executes an action as well as when one observes the same action being executed by others. Although it is well established that emotion modulates the motor system, the effect of observing other individuals acting in an emotional context is particularly elusive. The main aim of this study was to investigate the effect induced by the observation of grasping directed to emotion-laden objects upon corticospinal excitability (CSE). Participants classified video-clips depicting the right-hand of an actor grasping emotion-laden objects. Twenty video-clips differing in terms of valence but balanced in arousal level were selected. Motor evoked potentials (MEPs) were then recorded from the first dorsal interosseous using transcranial magnetic stimulation (TMS) while the participants observed the selected emotional video-clips. During the video-clip presentation, TMS pulses were randomly applied at one of two different time points of grasping: (1) maximum grip aperture, and (2) object contact time. CSE was higher during the observation of grasping directed to unpleasant objects compared to pleasant ones. These results indicate that when someone observes an action of grasping directed to emotion-laden objects, the effect of the object valence promotes a specific modulation over the motor system.Fil: Nogueira Campos, Anaelli A.. Universidade Federal de Juiz de Fora; BrasilFil: Saunier, Ghislain. Universidade Federal do Pará; BrasilFil: Della Maggiore, Valeria Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: De Oliveira, Laura A. S.. Centro Universitário Augusto Motta; BrasilFil: Rodrigues, Erika C.. Centro Universitário Augusto Motta; BrasilFil: Vargas, Claudia D.. Universidade Federal do Rio de Janeiro; Brasi

Efficiency of low versus high airline pressure in stunning cattle with a pneumatically powered penetrating captive bolt gun

The efficiency of stunning cattle was assessed in 443 animals (304 pure Zebu and 139 crossbred cattle), being mainly mature bulls and cows. Cattle were stunned using a Jarvis pneumatically powered penetrating captive bolt gun operating with low (160–175 psi, N = 82) and high (190 psi, N = 363) airline pressure, which was within the manufactures specifications. Signs of brain function and the position of the shots on the heads were recorded after stunning. Velocity of the captive bolt and its physical parameters were calculated. Cattle shot with low pressures showed more rhythmic respiration (27 vs. 8%, P < 0.001), less tongue protrusion (4 vs. 12%, P = 0.03) and less masseter relaxation (22 vs. 48%, P < 0.001). There was an increased frequency of shots in the ideal position when cattle were shot with the low compared to high airline pressures (15.3 vs. 3.1%). Bolt velocity and its physical parameters were significantly (P < 0.01) higher when using high pressure. Airline pressures below 190 psi are inappropriate when shooting adult Zebu beef cattle with pneumatically powered penetrating captive bolt guns

Alteraciones en la tasa de respiración de Daphnia magna bajo concentraciones subletales de anatoxina-a

Anatoxina-a es una potente neurotoxina producida por cianobacterias dulceacuícolas que puede representar un riesgo, por sus efectos agudos, para diferentes formas de vida, incluyendo los seres humanos. Aunque se conocen los efectos agudos y crónicos de esta toxina, pocos estudios aportan datos de medidas de efectos subletales sobre la respiración del zooplancton. En este trabajo se cuantifican cambios en la respiración de Daphnia magna bajo una concentración subletal de anatoxina-a, en condiciones experimentales, por medio de un sistema automatizado de medida en continuo de consumo de Oxígeno. Los resultados indican que la presencia de anatoxina-a en dosis subletales reduce significativamente la actividad respiratoria en esta especie, con efectos, dependientes de la edad del organismo.Anatoxin-a is a potent neurotoxin produced by some freshwater cyanobacteria which, because of its acute toxic effects, may represent a hazard to aquatic organisms, and even to human beings. Both the acute and chronic effects of this toxin are rather well known, but few studies provided information about its sublethal effect on the zooplankton respiration. In this paper we have quantified respiration changes in Daphnia magna under sublethal anatoxin-a concentrations in experimental conditions, using an automatic open-flow system of continuous measurement of oxygen consumption. Our results show that the presence of anatoxin-a at sublethal doses reduces significantly the respiratory activity of the animals, being the effects greatly dependent on the individual age

Dotted and Undotted Algebraic Spinor Fields in General Relativity

We investigate using Clifford algebra methods the theory of algebraic dotted and undotted spinor fields over a Lorentzian spacetime and their realizations as matrix spinor fields, which are the usual dotted and undotted two component spinor fields. We found that some ad hoc rules postulated for the covariant derivatives of Pauli sigma matrices and also for the Dirac gamma matrices in General Relativity cover important physical meaning, which is not apparent in the usual matrix presentation of the theory of two components dotted and undotted spinor fields. We also discuss some issues related to the the previous one and which appear in a proposed "unified" theory of gravitation and electromagnetism which use two components dotted and undotted spinor fields and also paravector fields, which are particular sections of the even subundle of the Clifford bundle of spacetime.Comment: some new misprints have been correcte

Conflits pour la terre et assassinats au Brésil

La forte concentration foncière et l'absence d'une politique de réforme agraire au Brésil sont les principales causes des conflits sociaux qui se soldent par l'assassinat de paysans et de leurs défenseurs. (Résumé d'auteur