The Amazon Basin is a special contributor to global biogeochemistry, particularly from the white water region related to the Andes mountains, a source of major Amazon river tributaries. White water composition and properties are rarely determined. Therefore, it is essential to know the spatial distribution and temporal variability of these waters to assess possible human influences on their chemical characterization. In this paper, a study performed in the Southwestern Amazon region, examining the chemical composition of the Acre River water is presented. This part of the Amazon Basin has not been studied sufficiently to determine the geochemistry of its white waters. pH, electric conductivity (EC), turbidity, and concentration of metals, anions and dissolved organic carbon (DOC) were measured from 2008 to 2014. Approximately 60% of the pH measurements had values between 6.5 and 7.3; 55% of the conductivity measurements had values between 30 and 60 -S cm-1; and 50 % of the turbidity measurements had values less than 100 NTU. The major soluble elements were Ca, Si and K. These species have a natural origin (clay minerals and quartz). Toxic elements (e.g., V, Ni, Cr and Pb) and the anions NO3- and SO42- were present at concentrations below the Brazilian Standards. The Na+, SO42- and Al concentrations are seasonally variable depending on water discharge. Major ions such as Mg and Ca showed a positive linear correlation with DOC.

The modeling of seasonal and interannual streamflow forecasting at northeastern Brazil represents a great relevance problem to the use and management of water resources; which demands greater prediction ability models. This is still a difficult task to solve due to the seasonal and interannual climate variability at the semi-arid region. This work presents the artificial neural networks (ANN) as an alternative for modeling the seasonal to interannual climate prediction,. For the development of this task the hydropraphic Oros weir Basin was chosen due to its importance as water resources in the State of Ceara. According to recent studies, the temperatures of the North Atlantic, South Atlantic and equatorial Pacific can be satisfactorily as predictors for the Northeast climate. The proposed model predicts, in July, the next rainy season (January to June) river flow regime. This time frame is of great relevance for the allocation of water resources. Among the studied models, those using the average temperature anomalies of April, May and June preceding the predicted year as input data showed the highest Nash-Suttcliffe efficiency (0.80).

O Semiárido brasileiro está sujeito a secas cada vez mais severas em razão das mudanças climáticas, o que exige a adoção de medidas mitigadoras e adaptativas. Essas medidas serão mais eficientes se favorecerem ações proativas que minimizem a vulnerabilidade e gerenciem o risco de secas. A captação e o armazenamento da água de chuva em cisternas foram idealizados como medidas de gestão do risco e têm sido apontados como estratégia de sucesso no processo de adaptação de comunidades vulneráveis à seca. No entanto, os mecanismos de suporte ao uso das cisternas possuem falhas, favorecendo seu uso na gestão de crise para o armazenamento não água de chuva, mas da fornecida por carros-pipas. Com base nesses pressupostos e utilizando dados disponibilizados pelo Observatório da Seca, apresentam-se reflexões acerca da eficácia das cisternas como medida de adaptação e gestão do risco. Foi observado que as cisternas são úteis na gestão do risco e da crise, no entanto ainda há dificuldades em se mensurar sua contribuição para a redução da vulnerabilidade à seca. Além disso, os problemas relacionados ao sistema podem contribuir para seu emprego prioritário na gestão da crise, ao invés de assumir o seu papel genuíno de adaptação e gestão de riscos.

The thermodynamics of the seasonal evolution of the Southwestern Tropical Atlantic Warm Pool (hereafter SWTAWP), which is delimited by the 28 °C isotherm, is investigated using the Regional Ocean Modeling System (ROMS). Results indicate that the net heat flux is responsible for the appearance and extinction of the SWTAWP. From March to May, the SWTAWP attains its maximum development and sometimes merges with equatorial warm waters towards the African continent, whose development follows the same period. Along the equator, the combination of oceanic terms (i.e., advection and diffusion) is important to promote the separation – when it occurs – of equatorial warm waters from southwestern tropical waters, which develops off the Brazilian coast. An analysis of the relative contribution of the temperature tendency terms of the mixed layer (ML) heat budget over the appearance, development and extinction of the SWTAWP is also done. The most important term for warming and cooling inside of the ML is the net heat flux at the sea surface. The ML is heated by the atmosphere between October and April, whereas the upper ocean cools down between May and September. The highest heat content values occur during the lower-temperature period (August to October), which is linked to the deepening of the ML during this time period. The horizontal advection along the equator is important, particularly at the eastern domain, which is influenced by the cold tongue. In this area, the vertical diffusive term is also significant; however, it presents values near zero outside the equator. These results contribute to a better understanding of the behavior of the heat budget within the tropical Atlantic, as previous studies over this region focused along the equator only.

The ocean temperatures and zonal currents at the equatorial Atlantic simulated by an improved version of the Brazilian earth system model (BESM), with changes in the cloud cover scheme and optical properties of the atmospheric component, are analyzed and compared to those obtained from a previous version of BESM and also from other seven selected CMIP5 models. It is shown that this updated version of BESM, despite some persistent biases, more accurately represents the surface temperature variation at the Equator and the equatorial thermocline east–west slope. These improvements are associated to a more realistic seasonal cycle achieved for the Atlantic equatorial undercurrent, as well as sea surface temperatures and zonal wind stress. The better simulation of the equatorial undercurrent is, in its turn, credited to a more realistic representation of the surface wind position and strength at the tropical Atlantic by the coupled model. With many of the systematic errors noticed in the previous version of the model alleviated, this version of BESM can be considered as a useful tool for modelers involved in Atlantic variability studies.

The purpose of this article is to evaluate the performance, in terms of specific consumption in g/kWh, of biodiesel produced from soybean oil, palm oil and residual frying oil, by means of ethylic and methylic routes, in blending percentages of 20% and 50%, at different power levels, for electric power generation from stationary internal combustion engines. The results are evaluated by Tukey′s range test, which enables the comparison of any and all contrasts between two averages of a variable. The results evidence that the 20% blend of biodiesel from soybean oil produced by methylic route seems to be the one whose performance is the closest to the reference fuel′s, and that the proportion of biodiesel has affected more significantly the performance of the blend tested than the type of raw material or route, in relation to the specific consumption for all power levels.

This study aims to describe the general importance of landscaping applied to urban environmental quality. This is a bibliographic review, where data were collected by consulting the selected search through the database Scielo and Google scholar, through scientific publications scientific articles. The material was categorized into two approaches: relationship of landscaping and urban forestry for environmental remediation and notes the contribution of landscaping measures. Several studies have explained the importance of the role of landscaping in urban areas, as well as its contribution to environmental improvement. Numerous measures are adopted that provide beyond the environmental, aesthetic and social.

O objetivo deste artigo é mapear e discutir algumas tendências e enfoques analíticos que vêm sendo conduzidos em teses e dissertações do campo da Educação que se valem dos Estudos Culturais para a abordagem da temática indígena. Foram analisados 14 trabalhos que articulam três descritores: temática indígena, Estudos Culturais e Educação. Verificou-se que, em tais produções, problematiza-se a ideia abstrata de diversidade cultural, tão mobilizada pelas perspectivas multiculturalistas. Além disso, constatou-se que o campo dos Estudos Culturais favorece o desenvolvimento de análises críticas que focalizam as desigualdades, as relações de poder, as práticas representacionais e as políticas em torno das identidades/diferenças. São acionados, nestes estudos, diversos conceitos e abordagens teóricas que problematizam visões eurocêntricas, repertórios depreciativos e essencialismos, mostrando que há uma tendência hegemônica de atribuir ao “outro”/indígena características que fazem dele um ser estranho, objeto de curiosidade e de escrutínio.

Este artigo analisa a experiência coletiva que se desenvolve desde meados dos anos 1980 na comunidade rural de Lagoa dos Cavalos (Russas, Ceará), no Semiárido nordestino, cujas terras são resultantes de partilha por herança, e onde se registra uma forma peculiar de organização que garante à população certa autonomia nas decisões coletivas sobre o desenvolvimento local. O objetivo é verificar a quem são delegados poder e responsabilidade no processo de coordenação da ação coletiva, seu perfil e seus papéis. Optou-se pela pesquisa qualitativa, combinando o uso de fontes testemunhais, documentais e bibliográficas. Utilizou-se a amostragem não probabilística intencional na definição dos atores entrevistados. A conclusão aponta que poder e responsabilidade são delegados a dois tipos de lideranças locais que detêm o reconhecimento e a legitimidade para o atendimento das demandas inerentes aos trabalhos de coordenação das atividades coletivas ou para mediação entre população local, assessores externos e o mundo, conservando relativa autonomia. Os assessores externos prestam apoio técnico e político, além de facilitarem o acesso a recursos financeiros. Ambos, lideranças locais e assessores externos, têm papel importante no desenvolvimento local. Mas são dependentes da organização local, que tem criado mecanismos que permitem construir a cooperação e a coordenação da ação dos atores envolvidos.