Patrones de comportamiento y alimentación del mono aullador Alouatta belzebul en zonas de selva talada y sin talar del este de la Amazonia

This work compared the activity patterns and diet of a group of Alouatta belzebul in areas of logged and unlogged forest in eastern Amazonia. An instantaneous scan sampling procedure was used for the behavioral study (9.3 ± 1.9 complete observation days/month) from February to November 2000. Fruit availability was estimated monthly. Activity budgets were not significantly different between sites. Rest was the predominant activity in both sites (53.6 % and 48.7 %, respectively). Average daily path length was 683.5 ± 215.1 m (n = 93), and the home range was 17.8 ha, including 7 ha in unlogged forest and 10.8 ha in the logged forest. Neither fruit availability nor diet varied significantly between sites. The diet was predominantly folivorous (43.4 % and 46.6 % in unlogged and logged forest, respectively) and frugivorous (43.9 % and 42.8 %). The spatial use by the group was positively related to fruit sources. This study documented the ability of a ranging group of A. belzebul to survive in a habitat influenced by reduced impact logging without dramatically influencing its activity patterns and diet.En este trabajo se comparan los patrones de comportamiento y alimentación de un grupo de Alouatta belzebul en zonas de selva deforestada y sin deforestar del este de la Amazonia. Para el estudio del comportamiento se utilizó un muestreo de barrido temporal instantáneo (observación completa durante 9,3 ± 1,9 meses/días) entre los meses de febrero y noviembre de 2000. La disponibilidad de fruta se calculó mensualmente. Las actividades realizadas no fueron significativamente diferentes en ninguna de las dos ubicaciones. El descanso fue la actividad predominante en ambas, 53,6 % y 48.7 % respectivamente. La media de la longitud de los recorridos diarios era de 683,5 ± 215,1 m (n = 93) y el área de acción era de de 17,8 hectáreas, incluyendo 7 hectáreas de selva sin talar y 10,8 hectáreas de bosques talados. Ni la disponibilidad de fruta ni la dieta variaron significativamente entre las zonas. La dieta era eminentemente folívora (43,4 % y 46,6 % en las zonas de selva sin talar y deforestada, respectivamente) y frugívora (43,9 % y 42,8 %). El uso que el grupo hacía del espacio estaba relacionado de manera positiva con las fuentes de suministro de frutas. En este estudio se ha documentado la habilidad de un grupo de A. belzebul en libertad para sobrevivir en un hábitat afectado por una tala de impacto reducido sin que ello afectase dramáticamente a sus patrones de comportamiento y alimentación

EVALUATION OF STATIC PRESSURE BEHAVIOR IN AN OSCILLATING WATER COLUMN WAVE ENERGY CONVERTER

The international scenario of non-renewable resources scarcity coupled with increasing energy demand are incentives for the diversification of the world's energy matrix with a focus on renewable energy sources. Among these sources, energy from sea waves is especially attractive because its global resource is estimated around 2 TW, comparable to the average electrical power consumed worldwide each year. There are currently several technologies proposed for the sea wave energy conversion into electricity. Among them it stands out the Oscillating Water Column (OWC) converter, which basically consists of a hydropneumatic chamber and a turbine duct where a turbine is installed. Its chamber is opened below the sea water free surface while the turbine duct outlet is free to atmosphere. Inside the chamber the water free surface oscillating movement produced by the incident waves causes the air to flow through the turbine duct and to activate the turbine, so the OWC principle of operating can be approximated to a cylinder-piston system. Therefore, one of the methodologies used in the computational modeling to simulate the operating principle of this device is the Piston Methodology, which simplifies the problem analysis considering only the air flow through the OWC converter. Among the phenomena that occur within the OWC device, the static pressure behavior is arguably one of the most important because it is through it that it is possible to estimate the hydropneumatic power and the converter efficiency. Thus, the objective of this work is to evaluate the static pressure behavior within the OWC, using the Piston Methodology, by imposing a monochromatic wave boundary condition in an axisymmetric domain. Among the obtained results it was inferred that the static pressure, in this case, depends directly on the flow acceleration and it is strongly influenced by the vorticity generated in domains with a change of area

Thunderstorm and Lightning Characteristics Associated With Sprites in Brazil

A study of the thunderstorm and cloud-ground lightning characteristics associated with sprite events observed in Brazil is presented. The study is based on ground and aircraft sprite observations with high sensitivity intensified CCD cameras of six different thunderstorms, GOES satellite infrared images, radar and lightning network data. A total of eighteen transient optical events were recorded at three different days in 2002 and 2003, sixteen of which exhibited vertical structures typically associated with sprites. Four thunderstorms were associated with two different cold fronts, one with a Mesoscale Convective System, and one was a local isolated thunderstorm. The sprites occurred during time periods when the percentage of positive flashes was higher than the average percentage for the storm lifetime. The lightning associated with the sprite events was all positive flashes with a mean peak current higher than the mean value for all flashes in the storms

Strong Electric Fields From Positive Lightning Strokes in the Stratosphere

A balloon payload launched in Brazil has measured vector electric fields from lightning at least an order of magnitude larger than previously reported above 30 km in the stratosphere. During the flight hundreds of lightning events were recorded, including several positive cloud to ground lightning strokes. A two stroke flash, with small (15 kA peak current) and moderate (53 kA) positive strokes at a horizontal range of 34 km, produced field changes over 140 V/m at 34 km altitude. On-board optical lightning detection, recorded with GPS timing, coupled with ground based lightning location gives high time resolution for study of the electric field transient propagation. These measurements imply that lightning electric fields in the mesosphere over large thunderstorms may be much larger than previously measured

High-speed video observations of positive ground flashes produced by intracloud lightning, Geophys

[1] High-speed video recordings of two lightning flashes confirm that positive cloud-to-ground (CG) strokes can be produced by extensive horizontal intracloud (IC) discharges within and near the cloud base. These recordings constitute the first observations of CG leaders emanating from IC discharges of either polarity. In one case, the discharge began with a negative leader that propagated horizontally, went upward and produced an IC discharge. After the beginning of the IC discharge, a positive leader emanated from the lowest portion of the IC discharge, and initiated a positive return stroke. In the other case, the IC discharge began with a positive leader and then initiated a downwardpropagating positive leader that contained recoil processes and produced a bright return stroke followed by a long continuing luminosity. These observations help to understand the complex genesis of positive CG flashes, why IC lightning commonly precedes them and why extensive horizontal channels are often involved

ANALISE TÉCNICA VERSUS HIPÓTESE DOS MERCADOS EFICIENTES: UM ESTUDO UTILIZANDO O INDICADOR MACD

Este trabalho testa a estratégia de investimento, pertencente à análise técnica, denominada Moving Average Convergence/Divergence – MACD, em 28 ações da Bolsa de Valores de São Paulo no período de julho de 1994 a julho de 2003. Verificou-se, após serem levados em conta os custos de transação, que, apesar da obtenção de 10 retornos superiores à estratégia passiva, nenhum deles foi estatisticamente significante. Observou-se, contudo, uma correlação negativa entre a liquidez da ação em bolsa e o valor da estatística t de Student para a diferença entre os retornos obtidos via MACD e a estratégia passiva correspondente. Isto dá suporte à idéia de que quanto mais (menos) eficiente é o mercado de ações, menos (mais) eficiente é a estratégia MACD. Palavras-chave: Análise técnica. MACD. Mercados eficientes

EVALUATION OF STATIC PRESSURE BEHAVIOR IN AN OSCILLATING WATER COLUMN WAVE ENERGY CONVERTER

The international scenario of non-renewable resources scarcity coupled with increasing energy demand are incentives for the diversification of the world's energy matrix with a focus on renewable energy sources. Among these sources, energy from sea waves is especially attractive because its global resource is estimated around 2 TW, comparable to the average electrical power consumed worldwide each year. There are currently several technologies proposed for the sea wave energy conversion into electricity. Among them it stands out the Oscillating Water Column (OWC) converter, which basically consists of a hydropneumatic chamber and a turbine duct where a turbine is installed. Its chamber is opened below the sea water free surface while the turbine duct outlet is free to atmosphere. Inside the chamber the water free surface oscillating movement produced by the incident waves causes the air to flow through the turbine duct and to activate the turbine, so the OWC principle of operating can be approximated to a cylinder-piston system. Therefore, one of the methodologies used in the computational modeling to simulate the operating principle of this device is the Piston Methodology, which simplifies the problem analysis considering only the air flow through the OWC converter. Among the phenomena that occur within the OWC device, the static pressure behavior is arguably one of the most important because it is through it that it is possible to estimate the hydropneumatic power and the converter efficiency. Thus, the objective of this work is to evaluate the static pressure behavior within the OWC, using the Piston Methodology, by imposing a monochromatic wave boundary condition in an axisymmetric domain. Among the obtained results it was inferred that the static pressure, in this case, depends directly on the flow acceleration and it is strongly influenced by the vorticity generated in domains with a change of area

A Very Active Sprite-Producing Storm Observed Over Argentina

During the night of 22–23 February 2006, more than 400 middle- atmospheric optical discharges were observed above one large thunderstorm system over northeastern Argentina. These transient luminous events (TLEs) were imaged during the Southern Brazil Sprite Campaign, the first campaign to focus on TLEs over southern Brazil, northeastern Argentina, and Uruguay. All of the TLEs were imaged from the Brazilian Southern Space Observatory (SSO) near Santa Maria, which is nearly in the center of the southernmost Brazilian state of Rio Grande do Sul. Although the fields of view of the imaging cameras were too narrow to view the entire storm, the more than 400 confirmed TLEs imaged indicate that this storm ranks as the third most active TLE producer ever reported. Hence, storms in this region of South America might be some of the leading TLE generators on Earth