Influência das práticas de manejo orgânico e convencional na qualidade do solo em produção familiar de hortaliças.

Este estudo teve objetivo de avaliar indicadores físicos e biológicos do solo que, inseridos no Módulo complementar “Capacidade produtiva do solo”, avaliem o impacto das práticas agrícolas sobre diferentes manejos do solo. Para efeito comparativo e complementar, serão avaliados os indicadores químicos. Análises de parâmetros químicos, físicos e biológicos foram realizadas em cinco propriedades de cada sistema, orgânico e convencional, selecionadas em Ibiúna e Socorro, SP. Em todas as propriedades, os indicadores físicos estabilidade de agregados, aeração e compactação contribuíram para os impactos ambientais (IA) negativos, conseqüência do baixo aporte de matéria orgânica diversificado, solos descobertos e com excessiva mecanização do solo. Este fato foi complementado pela presença de mofo branco (Sclerotinia sclerotiorum) e redução da atividade microbiana no solo

Evolving division of labor in a response threshold model

The response threshold model explains the emergence of division of labor (i.e., task specialization) in an unstructured population by assuming that the individuals have different propensities to work on different tasks. The incentive to attend to a particular task increases when the task is left unattended and decreases when individuals work on it. Here we derive mean-field equations for the stimulus dynamics and show that they exhibit complex attractors through period-doubling bifurcation cascades when the noise disrupting the thresholds is small. In addition, we show how the fixed threshold can be set to ensure specialization in both the transient and equilibrium regimes of the stimulus dynamics. However, a complete explanation of the emergence of division of labor requires that we address the question of where the threshold variation comes from, starting from a homogeneous population. We then study a structured population scenario, where the population is divided into a large number of independent groups of equal size, and the fitness of a group is proportional to the weighted mean work performed on the tasks during a fixed period of time. Using a winner-take-all strategy to model group competition and assuming an initial homogeneous metapopulation, we find that a substantial fraction of workers specialize in each task, without the need to penalize task switching

Percepções de pacientes sobre catarata

OBJECTIVE: To identify in adult patients suffering from cataract the perceptions regarding the disease and its surgical treatment. MATERIALS AND METHODS: An exploratory survey was conducted among adult patients suffering from cataract and participating in a large-scale cataract management program at the University of São Paulo General Hospital in 2004. The interviews were conducted by research assistants previously trained to pose questions and record answers. RESULTS: The sample consisted of 170 men and women (43.5% and 56.5%, respectively), aged between 40 and 88 years. Of the 170 participants, 43.5% were from the State of São Paulo, 14.7% from the State of Bahia, 12.4% from the State of Minas Gerais, 5.9% from the State of Pernambuco, 1.8% from other countries, and the remaining 21.7% were from other Brazilian states. Of those who were actively working (n = 87), 43.7% had an occupational level corresponding to nonspecialized manual labor, 27.6% were in specialized manual labor jobs, 25.3% had routine nonmanual occupations, 1.1% supervised manual labor, and 2.3% had low-ranking supervision or inspection jobs over nonmanual occupations. Of those who were not actively working (n = 82), 53.6% were retired, 45.2% were housewives, and 1.2% were unemployed. Concerning conceptions about cataract, 79.0% referred to it as "a small skin fold that gradually covers the eye" and 32.4% mentioned, in addition, other conceptions. Concerning the cause, of the alternatives presented to them, 80% reported aging, 47.1% blamed "overusing the eyes in the workplace or at home", 7.1% believed they had cataract due to some kind of "spell." Of the associated answers, 94.1% referred to "blurred vision" in people suffering from cataract, 72.4% thought the person may become blind, and 66.5% believed that the patients suffering from cataract are depressed because they cannot see. Regarding surgery, 28.8% were afraid of undergoing surgery; of those, 16.3% cited with the fear of dying during surgery, 55.1% thought they might become blind, 40.8% believed the surgery would be painful, and 8.2% followed religious practices that do not permit surgery. CONCLUSION: Some misconceptions were identified, and the fear of blindness was the most mentioned reason for not seeking cataract surgery, which indicates the need for orientation.OBJETIVO: Identificar percepções de adultos portadores de catarata em relação à doença e ao tratamento cirúrgico. MATERIAIS E MÉTODOS: Foi realizada uma pesquisa exploratória entre pacientes adultos portadores de catarata presentes em mutirão em hospital universitário no ano de 2004. Auxiliares de pesquisa previamente treinados para formulação das questões e registros das respostas, encarregaram-se das entrevistas. RESULTADOS: A amostra foi composta por 170 sujeitos de ambos os sexos (43,5% do sexo masculino e 56,5% do sexo feminino) com idade entre 40 e 88 anos. Dos 170 participantes, 43,5% eram nascidos no estado de São Paulo, 14,7% na Bahia, 12,4% em Minas Gerais, 1,8% nasceram em outros paises e os demais sujeitos, em outros estados brasileiros.Da população ativa no mercado de trabalho (n=87), encontravam-se em nível de ocupação manual não especializada 43,7%; ocupação manual especializada 27,6%; ocupação de rotina não manual 25,3%; supervisão de trabalho manual 1,1%; posição baixa de supervisão ou inspeção , considerando ocupações não manuais,2,3 %. Entre a população inativa no mercado de trabalho (n=82), 53,6% eram aposentados, 45,2% donas de casa e 1,2% desempregados. Em relação a concepção sobre catarata, 79,0% referiram ser uma "pelezinha que vai cobrindo os olhos" e 32,4% além da "pelezinha", mencionaram outras concepções. Em relação a causa , entre as opções fornecidas, 80% relacionam a velhice; 47,1% "por usar muito as vistas no serviço ou em casa"; 7,1% acreditam que tem catarata devido a "mau olhado". Dentre as respostas associadas, 94,1% referiram que a "visão fica embaçada" na pessoa que tem catarata, 72,4% acham que a pessoa pode ficar cega e 66,5% acham que os portadores de catarata ficam com depressão por não enxergarem. Vinte e oito por cento tem medo de se submeter a cirurgia, desses, 16,3% atribuem ao fato de poderem morrer na cirurgia; 55,1% acham que podem ficar cego; 40,8% crêem que a cirurgia dói e 8,2% tem medo de operar pois a religião não permite. CONCLUSÃO: Foram evidenciados alguns conhecimentos incorretos, o medo de ficar cego se fez presente entre as razões para não operar a catarata, indicando necessidade de provimento de orientação

Proposal for a radiation shielding study aiming the implantation of neutrons beam shutter in the J-9 radiation channel of the Argonauta reactor of the Nuclear Engineering Institute.

Argonauta, the only nuclear research reactor situated in Rio de Janeiro, located at the Institute of Nuclear Engineering (IEN), regularly serves a network of users focused on research and development, and also provides its infrastructure for experimental classes and completion work course. Due to increasing demand for non-destructive thermal neutron assays and production of radioisotopes, there is a search for new procedures and/or devices that optimize users' exposure to neutrons. The implementation of mechanisms that allow access to the irradiation channels without the reactor being turned off and with a shielding configuration that limits the occupational doses at this location is very useful for the operation of the reactor. In order to achieve this, the present work proposes the establishment of a neutron beam shutter of the J-9 irradiation channel of the IEN’s Argonauta reactor. In a first step, experimental measurements were made in the irradiation channel of the reactor using a BF3 detector, which is coupled to a spectrometer. In this phase, the neutron beam was aligned to the spectrometer, and different materials were used as shields, aiming the attenuation of the beam. To validate and/or change the configuration of the barrier that best meets the material irradiation needs, a second planned phase is involving the neutron flux simulation of the reactor and the various shields with different boundary conditions using the particle transport code, Monte Carlo N-Particle Extended (MCNP- X)

Characterization of Ant Communities (Hymenoptera: Formicidae) in Twigs in the Leaf Litter of the Atlantic Rainforest and Eucalyptus Trees in the Southeast Region of Brazil

Fragments of Atlantic Rainforest and extensive eucalyptus plantations are part of the landscape in the southeast region of Brazil. Many studies have been conducted on litter ant diversity in these forests, but there are few reports on the nesting sites. In the present study, we characterized the ant communities that nest in twigs in the leaf litter of dense ombrophilous forests and eucalyptus trees. The colony demographics associated with the physical structure of the nest were recorded. In the eucalyptus forests, the study examined both managed and unmanaged plantations. During five months, all undecomposed twigs between 10 and 30 cm in length containing ants found within a 16-m2 area on the surface of the leaf litter were collected. A total of 307 nests and 44 species were recorded. Pheidole, Solenopsis, and Camponotus were the most represented genera. Pheidole sp.13, Pheidole sp.43 and Linepithema neotropicum were the most populous species. The dense ombrophilous forest and a eucalyptus plantation unmanaged contained the highest number of colonized twigs; these communities were the most similar and the most species rich. Our results indicate that the twigs are important resources as they help to maintain the litter diversity of dense rain forest and abandoned eucalypt crops

Atrial fibrosis and decreased connexin 43 in rat hearts after exposure to high-intensity infrasound

Background: Noise is an important environmental risk factor. Industrial environments are rich in high-intensity infrasound (hi-IFS), which we have found to induce myocardial and coronary perivascular fibrosis in rats. The effects of exposure to IFS on the ventricles have been studied, but not on the atria. We hypothesized that rats exposed to hi-IFS develop atrial remodeling involving fibrosis and connexin 43, which we sought to evaluate. Material and methods: Seventy-two Wistar rats, half exposed to hi-IFS (120 dB, < 20 Hz) during a maximum period of 12 weeks and half age-matched controls, were studied. Atrial fibrosis was analyzed by Chromotropeaniline blue staining. The immunohistochemical evaluation of Cx43 was performed using the polyclonal antibody connexin-43 m diluted 1:1000 at 4 degrees C overnight. Digitized images were obtained with an optical microscope using 400 x magnifications. The measurements were performed using image J software. A two-way ANOVA model was used to compare the groups. Results: The mean values of the ratio "atrial fibrosis / cardiomyocytes" increased to a maximum of 0.1095 +/- 0,04 and 0.5408 +/- 0,01, and of the ratio "CX43 / cardiomyocytes" decreased to 0.0834 +/- 0,03 and 0.0966 +/- 0,03, respectively in IFS-exposed rats and controls. IFS-exposed rats exhibited a significantly higher ratio of fibrosis (p < .001) and lower ratio of Cx43 (p = .009). Conclusion: High-intensity infrasound exposure leads to an increase in atrial interstitial fibrosis and a decrease in connexin 43 in rat hearts. This finding reinforces the need for further experimental and clinical studies concerning the effects of exposure to infrasound

Water erosion in a Yellow-Red Ultisol under different patterns of simulated rain

Visou-se, neste trabalho, determinar as perdas de solo, água e nutrientes em um Argissolo Vermelho-Amarelo submetido a quatro diferentes padrões de chuva simulada. O estudo foi conduzido no Campo Experimental da Embrapa-Agrobiologia, localizado no município de Seropédica, RJ, e consistiu na aplicação de chuvas simuladas com diferentes padrões caracterizados como avançado (AV), intermediário (IN), atrasado (AT) e constante (CT), em uma área amostral de 0,80 m de largura por 1,0 m de comprimento. As chuvas tiveram duração de 60 min com uma lâmina total aplicada de 30 mm e um pico de 110 mm h-1, para os padrões de intensidade variável. Os resultados obtidos possibilitaram concluir que após 60 min de chuva simulada as perdas de solo e água observadas para o padrão atrasado foram, em média, superiores em 61,6, 46,4 e 13,6%, respectivamente, para o CT, AV e IN (solo), e de 42,0, 19,0 e 19,0%, respectivamente, para o AV, IN e CT (água) e as perdas de nutrientes não diferiram entre os padrões de precipitação, sendo mais influenciadas pelas perdas de água escoada superficialmente que pelo material sólido em suspensão.This study was carried out in order to determine the soil, water and nutrient losses in a Yellow-Red Ultisol, under four different patterns of simulated rainfall. The experiment was conducted at the Embrapa Agrobiologia experimental field, located in the municipality of Seropédica, Rio de Janeiro, Brazil. The study consisted in the application of simulated rains using variable rainfall intensity classified in different patterns as: advanced (AD), intermediate (IN), delayed (DE), and constant (CT), in plots 0.8 m wide and 1.0 m long. The rain had a duration of 60 min, with a total applied depth of 30 mm, and a peak of 110 mm h-1, for the variable intensity patterns. With the results obtained it was possible to verify that after 60 min of simulated DE pattern provided losses higher than CT, AD and IN, in 61.6, 46.4 and 13.6%, respectively (soil), and 42.0, 19.0 and 19.0% (run-off), respectively, for the AD, IN and CT patterns; and the nutrients losses did not differ among the rainfall patterns, being more affected by water run-off than solid material in suspension

Screening \u3ci\u3eBrachiaria\u3c/i\u3e Introductions for Resistance to Spittlebugs (Homoptera: Cercopidae)

Spittlebugs are the most evident and damaging pests of Signal grasses (Brachiaria) in tropical America. Damage caused by these insects can result in the complete loss of available forage, thereby reducing the carrying capacity of infested pastures. Host plant resistance is a low-cost method of controlling insects. High level of spittlebug resistance is found in the cultivar Marandu (B. brizantha), but it requires more fertile soils. Brachiaria germplasm provided by the International Center for Tropical Agriculture (CIAT) is available at National Beef Cattle Research Center of the Brazilian Agricultural Research Corporation (Embrapa Beef Cattle) and it is being screened for spittlebug resistance. In the present study, 23 introductions of Brachiaria were evaluated for resistance to the spittlebug Deois flavopicta, based on the parameters: nymphal survival and nymphal period. The introductions CIAT 16125 and CIAT 16309, both B. brizantha, were selected as resistant in this test. Given the great number of available introductions and hybrids, tests like this have been conducted routinely at Embrapa Beef Cattle. A total of 551 introductions and hybrids have already been screened in the past few years. As a result 40 introductions and 11 hybrids were found resistant. The aim of continuing evaluations is to release new spittlebug resistant Brachiaria cultivars