The influence of particles recycling on the geochemistry of sediments in a large tropical dam lake in the Amazonian region, Brazil

The influence of particles recycling on the geochemistry of sediments in a large tropical dam lake in the Amazonian region, Brazil. Article in Journal of South American Earth Sciences 72 · December 2016 DOI: 10.1016/j.jsames.2016.09.012 1st Rita Fonseca 16.85 · Universidade de Évora 2nd Catarina Pinho 3rd Manuela Oliveira 22.6 · Universidade de Évora Abstract As a result of over-erosion of soils, the fine particles, which contain the majority of nutrients, are easily washed away from soils, which become deficient in a host of components, accumulating in lakes. On one hand, the accumulation of nutrients-rich sediments are a problem, as they affect the quality of the overlying water and decrease the water storage capacity of the system; on the other hand, sediments may constitute an important resource, as they are often extremely rich in organic and inorganic nutrients in readily available forms. In the framework of an extensive work on the use of rock related materials to enhance the fertility of impoverish soils, this study aimed to evaluate the role on the nutrients cycle, of particles recycling processes from the watershed to the bottom of a large dam reservoir, at a wet tropical region under high weathering conditions. The study focus on the mineralogical transformations that clay particles undergo from the soils of the drainage basin to their final deposition within the reservoir and their influence in terms of the geochemical characteristics of sediments. We studied the bottom sediments that accumulate in two distinct seasonal periods in Tucuruí reservoir, located in the Amazonian Basin, Brazil, and soils from its drainage basin. The surface layers of sediments in twenty sampling points with variable depths, are representative of the different morphological sections of the reservoir. Nineteen soil samples, representing the main soil classes, were collected near the margins of the reservoir. Sediments and soils were subjected to the same array of physical, mineralogical and geochemical analyses: (1) texture, (2) characterization and semi-quantification of the clay fraction mineralogy and (3) geochemical analysis of the total concentration of major elements, organic compounds (organic C and nitrogen), soluble fractions of nutrients (P and K), exchangeable fractions (cation exchange capacity, exchangeable bases and acidity) and pH(H2O).

Cover Crops and Nitrogen Fertilization Effects on Nitrogen Soil Fractions under Corn Cultivation in a No-Tillage System.

ABSTRACT: The use of cover crops has recently increased and represents an essential practice for the sustainability of no-tillage systems in the Cerrado region. However, there is little information on the effects of nitrogen fertilization and cover crop use on nitrogen soil fractions. This study assessed changes in the N forms in soil cropped to cover crops prior to corn growing. The experiment consisted of a randomized complete block design arranged in split-plots with three replications. Cover crops were tested in the plots, and the N topdressing fertilization was assessed in the subplots. The following cover species were planted in succession to corn for eight years: Urochloa ruziziensis, Canavalia brasiliensis M. ex Benth, Cajanus cajan (L.) Millsp, and Sorghum bicolor (L.) Moench. After corn harvesting, the soil was sampled at depths of 0.00-0.10 and 0.10-0.20 m. The cover crops showed different effects at different soil depths. The soil cultivated with U. ruziziensis showed higher contents of total-N and particulate-N than the soil cultivated with C. cajan. Particulate-N was the most sensitive to changes in the soil management among the fractions of N assessed. The soil under N topdressing showed a lower content of available-N in the 0.10-0.20 m layer, which may be caused by the season in which the sampling was conducted or the greater uptake of the available-N by corn.

Using linear algebra for protein structural comparison and classification.

In this article, we describe a novel methodology to extract semantic characteristics from protein structures using linear algebra in order to compose structural signature vectors which may be used efficiently to compare and classify protein structures into fold families. These signatures are built from the pattern of hydrophobic intrachain interactions using Singular Value Decomposition (SVD) and Latent Semantic Indexing (LSI) techniques. Considering proteins as documents and contacts as terms, we have built a retrieval system which is able to find conserved contacts in samples of myoglobin fold family and to retrieve these proteins among proteins of varied folds with precision of up to 80%. The classifier is a web tool available at our laboratory website. Users can search for similar chains from a specific PDB, view and compare their contact maps and browse their structures using a JMol plug-in.

Charge accumulation and transport in degenerately doped semiconducting polymers with mixed ionic and electronic conductivity

This thesis is part of the fields of Material Physics and Organic Electronics and aims to determine the charge carrier density and mobility in the hydrated conducting polymer–polyelectrolyte blend PEDOT:PSS. This kind of material combines electronic semiconductor functionality with selective ionic transport, biocompatibility and electrochemical stability in water. This advantageous material properties combination makes PEDOT:PSS a unique material to build organic electrochemical transistors (OECTs), which have relevant application as amplifying transducers for bioelectronic signals. In order to measure charge carrier density and mobility, an innovative 4-wire, contact independent characterization technique was introduced, the electrolyte-gated van der Pauw (EgVDP) method, which was combined with electrochemical impedance spectroscopy. The technique was applied to macroscopic thin film samples and micro-structured PEDOT:PSS thin film devices fabricated using photolithography. The EgVDP method revealed to be effective for the measurements of holes’ mobility in hydrated PEDOT:PSS thin films, which resulted to be <μ>=(0.67±0.02) cm^2/(V*s). By comparing this result with 2-point-probe measurements, we found that contact resistance effects led to a mobility overestimation in the latter. Ion accumulation at the drain contact creates a gate-dependent potential barrier and is discussed as a probable reason for the overestimation in 2-point-probe measurements. The measured charge transport properties of PEDOT:PSS were analyzed in the framework of an extended drift-diffusion model. The extended model fits well also to the non-linear response in the transport characterization and results suggest a Gaussian DOS for PEDOT:PSS. The PEDOT:PSS-electrolyte interface capacitance resulted to be voltage-independent, confirming the hypothesis of its morphological origin, related to the separation between the electronic (PEDOT) and ionic (PSS) phases in the blend.

Unified control system for three-phase electric drives operating in magnetic saturation region

The research project aims to study and develop control techniques for a generalized three-phase and multi-phase electric drive able to efficiently manage most of the drive types available for traction application. The generalized approach is expanded to both linear and non- linear machines in magnetic saturation region starting from experimental flux characterization and applying the general inductance definition. The algorithm is able to manage fragmented drives powered from different batteries or energy sources and will be able to ensure operability even in case of faults in parts of the system. The algorithm was tested using model-in-the-loop in software environment and then applied on experimental test benches with collaboration of an external company.

Essays in nonlinear pricing and rent seeking

This thesis consists of three self-contained essays on nonlinear pricing and rent-seeking. In the first chapter of the thesis, I provide new theoretical insights about non-linear pricing in monopoly and common agency by combining the principal-agent framework with other-regarding preferences. I introduce a new theoretical model that separately characterizes status-seeker and inequity-averse buyers. I show how the buyer’s optimal choice of quality and market inefficiency change when the buyer has other-regarding preferences. In the second chapter, I find the optimal productive rent-seeking and sabotaging efforts when the prize is endogenous. I show that due to the existence of endogeneity, sabotaging the productive rent-seeking efforts causes sabotaging the endogenous part of the prize, which can affect the rent-seeking efforts. Moreover, I introduce social preferences into my model and characterize symmetric productive rent-seeking and sabotaging efforts. In the last chapter, I propose a new theoretical model regarding information disclosure with Bayesian persuasion in rent-seeking contests when the efforts are productive. I show that under one-sided incomplete information, information disclosure decision depends on both the marginal costs of efforts and the marginal benefit of aggregate exerted effort. I find that since the efforts are productive and add a positive surplus on the fixed rent, my model narrows down the conditions for the information disclosure compared to the exogenous model. Under the two-sided incomplete information case, I observe that there is a non-monotone relationship between optimal effort and posterior beliefs. Thus, it might be difficult to conclude whether a contest organizer should disclose any information to contestants.

Flora e aspectos auto-ecológicos de um encrave de cerrado na chapada do Araripe, Nordeste do Brasil

This study subject to investigate the floristic composition and richness, the reproductive phenological patterns, the dispersal syndromes and life forms of species of a disjunt cerrado in semiarid climate at Araripe plateau during a one year period. We found 107 species and 41 families. Fabaceae, Myrtaceae, Poaceae, Apocynaceae, Euphorbiaceae and Malpighiaceae showed the largest number of species. For 47 of the woody species found, we studied the geographical distribution based on 27 papers of the Brazilian cerrados. Twelve species are of widespread occurence in the cerrado, and 13 are restricted to the Araripe plateau. Zoocory, autocory, and anemocory are the predominant syndromes of dispersal. The predominant life forms were phanerophytes (50.7%), hemicriptophytes (14.9%) and camephytes (13.1%). The cerrado of Araripe have lower species richness than continous cerrados, but a similar pattern of reproductive phenology, dispersal syndromes and life forms in more humid zones.

Movimentos sociais na contemporaneidade

The work aims to present an overview of social movements in actuality, in the Latin America, and presents a mapping of their main forms in Brazil. The search ponders the educational character of their actions, both for its participants, as for society in general and public agencies. The basic premise of assertion that social movements are sources of innovation and knowledge-generating arrays. However, because it is not an isolated process but social-political character, the paper search joints in the network of relationships that establish movements in political, economic and socio-cultural country, to understand the factors that generate learning built and values of political culture that are being built. . The text highlights movements that occurs in the areas of education - formal and non-formal education.

Análise bayesiana do modelo de herança monogênica no melhoramento vegetal: um exemplo com abobrinha

A common breeding strategy is to carry out basic studies to investigate the hypothesis of a single gene controlling the trait (major gene) with or without polygenes of minor effect. In this study we used Bayesian inference to fit genetic additive-dominance models of inheritance to plant breeding experiments with multiple generations. Normal densities with different means, according to the major gene genotype, were considered in a linear model in which the design matrix of the genetic effects had unknown coefficients (which were estimated in individual basis). An actual data set from an inheritance study of partenocarpy in zucchini (Cucurbita pepo L.) was used for illustration. Model fitting included posterior probabilities for all individual genotypes. Analysis agrees with results in the literature but this approach was far more efficient than previous alternatives assuming that design matrix was known for the generations. Partenocarpy in zucchini is controlled by a major gene with important additive effect and partial dominance.

Variabilidade espacial da textura de um latossolo sob cultivo de citros

Relief influences soil texture variability, since it contributes to the time of exposition of the materials to weathering factors. Our work was carried out in the city of Gavião Peixoto (SP), with the objective of characterizing the spatial variability of texture of a dystrophic Red Latosol cultivated with citrus. The hillside was divided into three segments: top, stocking lean and inferior lean. Soil samples were collected in a grid with regular intervals of 50 m, at the depths of 0.0-0.2 m and 0.6-0.8 m, comprising a total of 332 points in an area of 83.5 ha. The data were submitted to descriptive and geostatistics analyses (semivariogram modeling and kriging maps). The spatial behavior of the texture of oxisols is directly related to the relief forms in this study, which controls the direction of surface and subsurface water flows. The concept of homogeneity of clay distribution in the Oxisol profile is a piece of information that can be adjusted by knowing the spatial pattern of this distribution in different relief forms.

Limiar ventilatorio e comportamento do sinal eletromiografico durante exercicio incremental no cicloergometro

Universidade Estadual de Campinas . Faculdade de Educação Física

Metabolismo mineral em bubalinos com ingestões de diferentes níveis de fósforo

Objetivou-se avaliar os efeitos da ingestão diária de quatro níveis de fósforo (8, 12, 15 e 18 g) sobre o metabolismo de macrominerais (P, Ca, Mg, Na, K e S), incluindo a ingestão, a concentração no rúmen, a taxa de passagem do líquido ruminal, a excreção nas fezes e a disponibilidade aparente. Utilizaram-se quatro bubalinos adultos com fístulas ruminais em delineamento quadrado latino (4 × 4) com dieta total constituída de cana-de-açúcar como volumoso (85%) e concentrado formulado com um dos níveis de fósforo. Os níveis de fósforo não ocasionaram diferença significativa na concentração mineral no rúmen de nenhum mineral estudado. A concentração média de fósforo no conteúdo ruminal foi de 0,98% na matéria seca, enquanto o teor de fósforo nas rações variou de 0,12 a 0,34%, comprovando alta reciclagem de fósforo pela saliva. Níveis crescentes de fósforo na dieta, variando de 8 a 18 g/animal/dia, não influenciam as disponibilidades de cálcio e magnésio. Com o nível de fósforo de 15 g/dia, houve melhor utilização do fósforo da dieta. A ingestão de níveis crescentes de fósforo em g/kg0,75 (X) promoveu aumento linear na excreção fecal desse mineral em g/kg0,75 (Y) e baixos valores de disponibilidade do fósforo, que pode ser estimado pela equação Y = 0,03 + 0,610X, o que indica deficiência desse elemento mineral na dieta para o metabolismo animal.

Epidemiologia da Leishmaniose Tegumentar e descrição das populações de flebotomíneos no município de Acrelândia, Acre, Brasil

São apresentadas neste artigo a distribuição da leishmaniose tegumentar (LT) e descrição das populações de flebotomíneos em Acrelândia, Acre. Os dados epidemiológicos foram obtidos a partir de fichas de notificação de casos ocorridos entre 2001 e 2004, e os dados entomológicos são provenientes de capturas com armadilhas luminosas efetuadas entre 2004 e 2005 na zona rural de Acrelândia. Ocorreram 82 novos casos de LT, com idade entre 2 e 69 anos, sendo 75,6% em homens e 83,9% na zona rural. Predominou a LT com lesões únicas (78%). A microscopia direta da lesão, intradermorreação de Montenegro e biópsia apresentaram positividade de 100%, 98% e 79,5%, respectivamente. A resposta ao tratamento farmacológico foi bem sucedida em 71,6% dos casos; a falência terapêutica foi maior em pacientes com diagnóstico exclusivamente clínico (41,2%) e nos que receberam dose diária inadequada de antimonial pentavalente (64,3%). Foram coletados 40 espécimes de flebotomíneos em propriedades rurais com casos de LT (3 gêneros, 14 espécies), sendo 3 espécies conhecidas como vetoras ou possíveis vetoras de Leishmania: Nyssomyia antunesi predominou no peridomicílio (59,1%) e em margens de matas; Nyssomyia whitmani foi freqüente no peridomicílio (15%) e a única espécie encontrada no intradomicílio, e Trichophoromyia ubiquitalis foi capturada no peridomicílio. O uso de dados epidemiológicos existentes no serviço de saúde de Acrelândia, embora com várias limitações, permitiu avaliar a eficácia do diagnóstico e o tratamento empregados no município, enquanto os dados entomológicos coletados podem orientar estudos mais amplos visando identificar os vetores e espécies circulantes na região.

Níveis de lisina digestível para frangos de corte machos no período de 37 a 49 dias de idade

Foram utilizados 1.015 frangos de corte machos, linhagem Ross, dos 37 aos 49 dias de idade, para avaliar os efeitos de diferentes níveis de lisina digestível nas dietas experimentais. O delineamento experimental foi inteiramente casualizado, com 5 níveis de lisina digestível (0,90; 0,95; 1,00; 1,05; 1,10%), cada um com 7 repetições e 29 aves por unidade experimental. Utilizaram-se dietas isoenergéticas com 3.250 de kcal de EM/kg e isoprotéicas, com 18% de PB, à base de milho e farelo de soja. Foram avaliados o ganho de peso, o consumo de ração, a conversão alimentar, as características de carcaça, o rendimento de cortes, a composição e a deposição de nutrientes corporais. Os níveis de lisina digestível influenciaram, entre as características de desempenho, apenas a conversão alimentar, que melhorou de forma linear de acordo com níveis de lisina da ração. Das características de carcaça e rendimento de cortes, apenas gordura abdominal aumentou de forma quadrática conforme os níveis de lisina. Os níveis de lisina digestível tiveram efeito quadrático no teor da matéria mineral da carcaça, mas não influenciaram a composição química das vísceras e do sangue. Observou-se, contudo, tendência a aumento linear na deposição de proteína da carcaça e do corpo vazio com o aumento no nível de lisina digestível. Os resultados de desempenho indicam que o nível de lisina digestível da ração de frangos de corte machos no período de 37 a 49 dias de idade deve ser igual ou superior a 1,10%.

Lisina digestível e zinco quelado para frangos de corte machos: desempenho e retenção de nitrogênio na fase pré-inicial

Em dois ensaios experimentais, avaliaram-se níveis de lisina digestível (0,90; 1,00; 1,10; 1,20 e 1,40%) combinados a zinco quelado (43 e 253 ppm) para frangos de corte machos. Os períodos considerados foram: 1 a 11 dias de idade (desempenho) e 1 a 7 dias de idade (balanço de nitrogênio). O delineamento experimental utilizado foi de blocos ao acaso, em esquema fatorial 5 × 2. No ensaio de desempenho, utilizaram-se 7 repetições e 15 aves por unidade experimental e, no ensaio de digestibilidade, 6 repetições e 6 aves por unidade experimental. As dietas continham 2.960 de EM/kg e 21% de proteína bruta. Na fase de 1 a 11 dias de idade, não houve efeito de interação lisina digestível × zinco quelado no desempenho, mas verificou-se efeito quadrático dos níveis de lisina digestível sobre o peso final, o ganho de peso e o ganho de peso relativo e efeito linear crescente no consumo de ração. A conversão alimentar não diferiu com as variações dos níveis de lisina digestível e zinco na dieta. Nas condições de avaliação do desempenho, o nível ótimo de lisina digestível para frangos de corte machos mantidos em piso de concreto é de 1,19%. Na fase de 1 a 7 dias de idade, não houve influência da relação entre níveis de lisina digestível e zinco quelado no balanço de nitrogênio. A retenção de nitrogênio aumentou de forma linear crescente com o aumento da concentração de lisina digestível na dieta, o que está de acordo com o aumento linear do ganho de peso e da eficiência alimentar. A exigência de lisina digestível para frangos de corte machos de 1 a 7 dias de idade é igual ou superior a 1,40%.