Efeitos do enriquecimento com nutrientes (N e P) em diferentes condições de luz sobre o crescimento do fitoplâncton em um reservatório eutrófico no semi-árido brasileiro

The increasing of pollution in aquatic ecosystems in the last decades has caused an expansion of eutrophication and loss of water quality for human consumption. The increase of frequency and intensity of cyanobacteria blooms have been recognized as a major problem connected to water quality and eutrophication. The knowledge of environmental factors controlling these blooms is a key step towards the management for recovering aquatic ecosystems from eutrophic conditions. Primary productivity in aquatic ecosystems is dependent on light and nutrients availability. In the present work we evaluated the relative importance of the concentration of major nutrients, such as phosphorus and nitrogen, and light for phytoplankton growth in the main water reservoir of Rio Grande do Norte State, named Engenheiro Armando Ribeiro Gonçalves (EARG), which is an eutrophic system, dominated by potentially toxic cyanobacteria populations. Limitation of phytoplankton growth was evaluated through bioassays using differential enrichment of nutrients (N and/or P) under two light conditions (low light and high light) and monthly monitoring of chlorophyll-a and nutrients (total nitrogen and phosphorus) concentrations, and water transparency (Secchi depth) at the pelagic region. Our results confirm that EARG reservoir is an eutrophic system with a low water quality. Results of bioassays on the growth of phytoplankton limitation (N or P) were conflicting with the results predicted by the TN:TP ratios, which indicates that these ratios were not a good indicator of algal growth limitation. Nitrogen was the limiting nutrient, considering both frequency and magnitude. Light and hidrology affected phytoplankton response to nutrient enrichment. The extreme eutrophic conditions of this reservoir, dominated by cyanobacteria blooms, demand urgent managing strategies in order to guarantee the multiple uses for this system, including water supply for human population. Although nitrogen is the limiting nutrient, an effective management program must focus on the reduction of both phosphorus and nitrogen input

Avaliação de tanques de escorva utilizados em substituição à válvula-de-pé em instalações de bombeamento

A maioria das instalações de abastecimento de água utiliza bombas hidráulicas do tipo turbobombas, requerendo que o interior de sua carcaça e da tubulação de sucção esteja preenchido com água (escorvados) para que a sucção da água possa ser efetivada. O escorvamento das bombas pode ser efetuado instalando-as abaixo do reservatório de captação (bomba afogada). Quando a bomba está acima do reservatório e o escorvamento é manual, é necessário usar válvulas-de-pé, que são suscetíveis ao mau funcionamento, limitando a confiabilidade do sistema, principalmente em caso de automação. Como alternativa à válvula-de-pé, neste trabalho, foram estudados dois tanques escorva, testados no Laboratório de Hidráulica e Irrigação da FCAV/UNESP - Jaboticabal, avaliando-se situações de altura manométrica de sucção de bomba centrífuga e relações entre volume útil do tanque e volume do tubo de sucção, tendo-se concluído: a) o volume do tanque de escorva é função do volume do tubo de sucção da instalação de bombeamento e da altura manométrica de sucção; b) o volume do tanque de escorva pode ser calculado seguindo-se a Lei de Boyle, com percentagem de acréscimo que, neste estudo, foi de 10% para um modelo de tanque e de 30% para o segundo modelo.

Expansão canavieira e ocupação formal em empresas sucroalcooleiras do Centro-Sul do Brasil, entre 2007 e 2009

Considerando-se a região Centro-Sul do Brasil e com base nos dados do Ministério do Trabalho e Emprego e do Ministério da Agricultura, Pecuária e Abastecimento, comparou-se a evoluçãoda produção sucroalcooleira comonúmero e tipos de pessoas formalmente ocupadas em empresas do setor, de 2007 a 2009. Nas empresas dedicadas ao cultivo da cana-de-açúcar, o número de pessoas ocupadas caiu nesses três anos, enquanto aumentava nas empresas dedicadas à produção de açúcareetanol.Quantoàscategoriasdeocupação,constatou-seaumentononúmero de pessoas ocupadas em atividades industriais, administrativas, de apoio ou não sucroalcooleiras, enquanto diminuíam as pessoas ocupadas na agricultura. Neste caso, houve redução dos trabalhadores canavieiros não qualificados e crescimento dos trabalhadores da mecanização agrícola, fatos associados à intensificação da adoção da colheita mecânica de cana-de-açúcar. Não ocorreu mudança expressiva na sazonalidade de emprego dos trabalhadores canavieiros não qualificados, que permaneceu muito alta. O aumento mais intenso da produção do que do número de pessoas ocupadas refletiu em indicadores de produtividade, com crescimento da relação da produção de cana-de-açúcar, tanto com o total de pessoas ocupadas, quanto com o número de trabalhadores canavieiros não qualificados. Também foi constatada redução significativa na relação desse grupo de trabalhadores com a área colhida com cana-de-açúcar.

Participação das principais frutas brasileiras no comércio internacional: 1997 a 2008

As tendências do mercado mundial de alimentos apontam para alto crescimento no consumo de produtos naturais, como as frutas e verduras. O mercado mundial de frutas frescas registrou, em 2005, cifra superior a US$ 31,5 bilhões e cresce US$ 1 bilhão ao ano, em média. Tal fato se reproduz no Brasil, onde se observa elevação do consumo de frutas. em termos monetários, o valor bruto da produção de frutas no Brasil atingiu, em 2006, cerca de R$ 16,3 bilhões, 16,5% do valor da produção agrícola brasileira. O presente trabalho buscou analisar características econômicas da participação brasileira no comércio mundial de frutas, entre 1997 e 2008. Ademais, foi analisada a evolução da balança comercial das principais frutas brasileiras, discriminação das exportações em frescas ou processadas, representatividade do comércio externo no valor da produção nacional e participação da exportação de frutas selecionadas na exportação total do agronegócio. Foram utilizados dados da Pesquisa de Orçamento Familiar (POF) do Instituto Brasileiro de Geografia e Estatística; o Sistema de Análise e Levantamento do Comércio Exterior - AliceWeb do Ministério do Desenvolvimento, Indústria e Comércio Exterior e o banco de dados do Ministério da Agricultura, Pecuária e Abastecimento. Após levantamento das frutas que seriam estudadas, constatou-se que o crescimento das exportações foi maior que o crescimento das importações brasileiras de 1997 a 2008. Isso contribuiu para que o seu saldo comercial aumentasse em 112% no período. As exportações de frutas frescas cresceram relativamente mais que as exportações de frutas processadas. Porém houve queda da participação das exportações de frutas nas exportações do agronegócio brasileiro, de 5,8%, em 1997, para 3,9%, em 2008.

Políticas públicas para agricultura familiar: uma avaliação sobre a correspondência do paa e do PRONAF nos territórios da cidadania do Rio Grande do Norte - 2008 a 2010.

Family farming has been considered as the new axis of rural development in the country, the focus of several public policies, especially the National Program for Strengthening Family Agriculture - PRONAF and Food Purchase Program - PAA. PRONAF was created with the aim of providing credit to farmers, while the PAA to support family farmers through the purchase of its production. In this context, the objective of this study is to analyze the correspondence of these two public policies for family farming, in the Territories of Citizenship of the state of Rio Grande do Norte, between the years 2008 to 2010. In the methodology, the analysis was performed by comparing the distributions of the two programs in the territories of citizenship status. There were also statistical tests of differences in proportions, and Spearman correlations, and estimated a logit regression model, in order to measure the probability of a farmer participating in the PAA is associated with one of the modes of PRONAF. The data used were obtained from the National and Supply - CONAB at the Institute of Technical Assistance and Rural Extension - EMATER, and the Ministry of Agrarian Development - MDA. Among the key findings was noted that policies were associated with a direct, but low in the districts of the Territories of Citizenship. And that, in the years 2008 and 2009, only in the territories of Mato Grande, Alto Oeste and Seridó, the actions of PAA and PRONAF had direct and significant correlations. It was found that in most of the territories, policies are performed randomly, ie that both have no correlation to each other. The estimates of the logit model showed that the chance of a family farmer, the PAA participant, receive credits PRONAF A, is higher in the territory of Mato Grande, and would have a chance to fall in PRONAF B in all areas surveyed. Moreover, farmers in the territories of the Assu-Mossoró, Sertão of Apodi, Seridó and Alto Oeste, participating in the PAA would be more likely to receive credits PRONAF C, reflecting thus the family farm more consolidated these territories

Caracterização da água da microbacia do córrego rico avaliada pelo índice de qualidade de água e de estado trófico

A avaliação do índice de qualidade da água (IQA) e do índice de estado trófico médio (IETm) pode subsidiar a formulação de planos de manejo e gestão de sistemas aquáticos. Neste trabalho, foi avaliada a qualidade da água da microbacia do Córrego Rico, que abastece a cidade de Jaboticabal (SP), utilizando o IQA e IETm. As amostragens de água foram realizadas entre setembro-2007 e agosto-2008, em três pontos: a) em uma das nascentes; b) após a Estação de Tratamento de Esgoto de Monte Alto, e c) na captação de água para abastecimento público de Jaboticabal. As amostras foram analisadas quanto aos parâmetros físicos, químicos e microbiológicos: temperatura, oxigênio dissolvido, pH, DBO5, nitrogênio total, fósforo total, turbidez, resíduo total, ortofosfato, clorofila-a e Escherichia coli. de acordo com os resultados obtidos, concluiu-se que: a) as atividades antrópicas às margens do Córrego Rico reduzem a qualidade de sua água, durante os diferentes períodos do ano; b) os valores médios de IQA nos três pontos analisados apresentaram relação direta com os valores médios de IETm, porém ocorreu maior discriminação da qualidade da água pelo IETm, identificando diferentes graus de trofia para os pontos e períodos de amostragens; c) o IQA apresentou melhor diferenciação da qualidade da água entre pontos no período seco e o IETm diferenciou melhor no período chuvoso; d) o processo de autodepuração e/ou a confluência do Córrego Tijuco com o Córrego Rico contribuem para melhor qualidade da água, tornando-a adequada ao abastecimento urbano após tratamento convencional.

Avaliação de equipamentos de aplicação de herbicidas em operação de repasse em cana-de-açúcar e segurança para o trabalhador

Objetivou-se com este trabalho classificar em seguras ou inseguras as condições de trabalho de aplicação da formulação comercial de paraquat a 0,5% e de abastecimento dos tanques em operação de repasse em cultura de cana-de-açúcar com os pulverizadores costal manual, costal pressurizado e Pulmipur manual; determinar o efeito das variações na operação de repasse em quatro usinas de açúcar e álcool com o pulverizador costal pressurizado sobre as exposições dos trabalhadores ao paraquat; determinar a eficácia de equipamentos de proteção individual nessas condições de trabalho; e avaliar a intensidade da deriva e a eficácia de acessórios protetores de deriva. As exposições dérmicas e respiratórias dos trabalhadores foram avaliadas e utilizadas para calcular a margem de segurança (MS). Os valores de MS foram utilizados para classificar essas condições de trabalho em seguras (MS > 1) ou em inseguras (MS < 1). Para avaliar a deriva das aplicações na cultura e a eficácia dos protetores de deriva, foram estudados os tratamentos: formulação comercial de paraquat a 0,5% na calda, aplicada com o costal manual, sem e com o chapéu de proteção de deriva; com o costal pressurizado, sem e com a planilha de proteção de deriva; formulação comercial de paraquat pura com o Pulmipur; formulação comercial de glyphosate a 1% com o costal pressurizado e com a planilha, e puro com o Pulmipur; e testemunha sem aplicação. As duas atividades com o Pulmipur proporcionam as maiores exposições dérmicas, devido ao manuseio da formulação, e são inseguras sem o uso dos EPIs e seguras com estes. As atividades com o pulverizador costal manual ou pressurizado são seguras com ou sem os EPIs. As grandes diferenças nas EDs dos trabalhadores se devem às diferenças no tempo de trabalho diário e no número de trabalhadores nas equipes entre as usinas de açúcar e álcool. O protetor de deriva tipo chapéu é eficaz no controle da deriva na aplicação do paraquat, e a planilha, não.

Água de consumo humano como fator de risco à saúde em propriedades rurais

OBJETIVO: Verificar a qualidade higiênico-sanitária da água de consumo humano em propriedades rurais por meio da contagem de indicadores microbiológicos de potabilidade. MÉTODOS: Foram colhidas 180 amostras de água utilizada para consumo humano das fontes, reservatórios e ponto de consumo em 30 propriedades rurais, situadas na região Nordeste do Estado de São Paulo. Determinou-se o número mais provável de coliformes totais, Escherichia coli e o número de microrganismos mesófilos. Foi verificada a presença de medidas de proteção das fontes de abastecimento. RESULTADOS: Os resultados evidenciaram que 90% das amostras de água das fontes, 90% dos reservatórios e 96,7% de água de consumo humano, colhidas no período de chuvas, e 83,3%, 96,7% e 90%, daquelas colhidas respectivamente nos mesmos locais, durante a estiagem, estavam fora dos padrões microbiológicos de potabilidade para água de consumo humano. CONCLUSÕES: A água utilizada nas propriedades rurais foi considerada um importante fator de risco à saúde dos seres humanos que a utilizam. A adoção de medidas preventivas, visando à preservação das fontes de água, e o tratamento das águas já comprometidas são as ferramentas necessárias para diminuir consideravelmente o risco de ocorrência de enfermidades de veiculação hídrica.

Bactérias do gênero Aeromonas em água de matadouro bovino

Verificou-se a ocorrência de bactérias do gênero Aeromonas em amostras de água (abastecimento/residuária) obtidas em matadouro bovino. Analisaram-se a água utilizada nas dependências internas, a água dos currais, utilizada na dessedentação, pré-higienização e tranqüilização dos animais e a água residuária da lavagem das carcaças. Das 30 amostras representativas de cada tipo, bactérias do gênero Aeromonas foram isoladas em 10 (33,3%) amostras da água dos currais e em 10 (33,3%) amostras da água residuária da lavagem de carcaças. Nenhuma das amostras da água tratada de abastecimento das instalações revelou-se positiva no isolamento. As espécies isoladas foram Aeromonas hydrophila em duas (2,2%) e Aeromonas caviae em 19 (21,1%) amostras. Uma cepa considerada atípica foi isolada da água dos currais. Os resultados evidenciaram que a água dos currais pode ser uma importante fonte de contaminação, principalmente para a pele, e através dela as Aeromonas sp. podem chegar à sala de matança.

Descompassos nas políticas educacionais: a reorganização da educação rural em Jardim de Piranhas/RN

The present work has as aim to analyze the reorganization process of the rural education in Jardim de Piranhas-RN, on the context of the education policies, in particular of the period of 1999-2006, having as reference the transformations in the political, cultural and socio-economic setting in the national, regional and local level, above all from the decade of 1990. The studies carried out in diverse sources made possible to understand from the context in which they had developed the education policies, in particular, that one directed for the rural way, as well as the mediation of this with the education reorganization in the local scope. Besides these research procedures, we carry out interviews - semi-structuralized - with managers and teachers, and we analyze documents from the produced ones in national level to those local ones. From the viewpoint theoretician-methodological, we focus the national discussion that comes developing under a new ideological political configuration and, being entitled by the Field Education, understood as a policy directed to education specifities in this sector and consolidated in the Operational Guidelines for the Basic Education in the Field Schools (CNE/MEC/2002). As particularity of this object in Jardim de Piranhas-RN, we emphasize events occurred that had marked the rural education reorganization in that city, especially from the creation of the Rural Education named Center Teacher Maria Edite Batista. Studies make possible to realize that until the Center creation, the schools functioned in rather precarious infrastructure and physical conditions, that is, without electric energy and water supplying, as well as the lack of school snack and the management structure. There was not a project or specific pedagogical accompaniment for the sector. Moreover, the teachers worked predominantly with several grade classes and still they fulfilled the manager functions, caretakers, and cook- in some cases as school secretary. However, exactly with the creation of the Rural Education Center, the education municipal system did not become capable to overcome problems as of the evasion and school failure, as well as decreasing the work overload of teachers, neither to give greater consistency to the pedagogical project of the field schools in that city

Automedicação e guarda de medicamentos por universitários das áreas de saúde e tecnologia

This study aimed to compare self-medication and domestic drug storage among undergraduate students in the areas of health and technology. This is a descriptive study of cross-sectional type and quantitative approach, conducted in a Public University of Natal, Rio Grande do Norte, Brazil. The sample consisted of 300 students of the third year of undergraduate courses at the Center for Health Sciences and Technology Center, selected through a simple random sample. The project was authorized by the Ethics Committee of Federal University of Rio Grande do Norte (CAAE 0137.0.051.000-10). Data collection lasted twelve months and was conducted during the period of study participants, in the university environment. The instrument for data collection was a structured questionnaire consisting of open and closed questions. For data analysis, we used descriptive statistics and applied Fisher s exact test and Chi-square test with adopted level of significance α=5% and 10%. For the variables that correlated with self-medication (p<0.05), we subsequently calculated the odds ratios and confidence intervals. The prevalence of undergraduate students who performed self-medication in the 15 days prior to the collection accounted for 33.7% and, by analyzing each knowledge area, we verified was a higher prevalence of self-medication among students in the technological area (37.3%). The analysis of the socio-demographic characteristics of the participants in this practice revealed a significant difference between the knowledge areas in the income and self-medication variables (p=0.005). General analgesics and antipyretics (N02) represent the therapy group most used in self-medication (57.4%), especially acetaminophen (28.7%), and the main health situations that motivated this practice related to pain, especially headaches (48.5%). Regarding the indication of the drugs used, the majority of students self-medicated themselves on their own (71.3%). As regards to the in-home drug storage, most of the participants had a home pharmacy (88%). By analyzing the socioeconomic characteristics, the variables medical service and home medicine presented a significant difference (p=0.002). General 10 analgesics and antipyretics constituted the medicinal products most found in the home pharmacies, especially acetaminophen. The main room used for the drug storage was the kitchen (36.4%), most students kept these products in boxes of different materials (38.6%) and the medicines stored at home of most of the participants were not easily accessible to children (75%). The results reinforce the need to develop strategies, from the reality found, aiming to encourage and implement educational and preventive activities with undergraduate students on the importance of proper self-medication and in-home drug storage. Despite the sample in our study is relatively small, not representative for the whole country, we believe that, at national level, the panorama of the subject does not present major differences

Impacto urbano ocasionado por empreendimentos da construção civil no entorno da zona de proteção ambiental (zpa-6), Vila de Ponta Negra, Natal/RN

The process of urbanization in recent decades has generated considerable seriousness of problems relating to the use and occupation physical environment of cities. The concentration of population, economic activities and technological standards have reinforced an existing urban environment highly degraded as a consequence of the development style that leads to the predatory use of natural resources. In this context, cities as centers of production and consumption, have the most serious problems of environmental degradation. This study investigated the impacts of the municipal building projects to large-scale vertical in the town of Vila de Ponta Negra, Natal-RN, given the proximity to the Environmental Protection Area (ZPA-6) and considering its environmental importance , scenic, landscape and tourism for the city of Natal-RN. The fragility of the licensing process and the failure of the assumptions in the analysis, objective and subjective, for the granting of environmental permits for the building construction projects, specifically those set out in the surroundings of the Environmental Protection Area (ZPA-6) and fundamental importance of landscape and tourism for the city of Natal, has aroused the concern of local people in and of itself the Government, faced with the probable impacts that will affect greatly the Vila de Ponta Negra. The methodology used to achieve the intended objectives will be the literature review, questionnaire to the surrounding population and the Government, as well as findings on the spot, through the photographic record. The beneficiaries of the license, if the entrepreneurs, have been affected because of the granting of licensing act of investing large amount of capital in the works. Additionally, with distrust of the population, since they are to discredit the public system of environmental management have guessed by the probability of imbalance to the environment and structural damage to the Vila de Ponta Negra, where such failure to support energy, lack of regular supply of water , lack of sanitation and access roads sufficient for the flow of motor vehicles in these areas, among other factors. Thus, this work will contribute to the diagnosis and solutions to the problem in question, so that the Government will effectively fulfill its social management of ecologically balanced environment of continuing urban development in Natal, Brazil

Diagnóstico Socioambiental da disposição final dos resíduos sólidos no distrito de Guajiru São Gonçalo do Amarante/RN, ressaltando a situação socioeconômica dos catadores

One of the concerns of this century is with the handling and the final destination of urban solid waste (RSU), where depending on the form as they will be made use, they can cause diverse problems, they are of ambient or social order, being able to generate the loss of the quality of life and illnesses to the population, of direct or indirect form. The objective of the present work was to diagnosis the environmental partner situation of the Final Destination of the urban solid residues in the District of Guajiru, city of São Gonçalo do Amarante/RN, standing out the partner-economic situation of the scavengers. The research was carried through in the period of March of 2008 the October of 2009, with a methodology developed through analyzes them of documents made available for the state ambient agency, the Air base of Christmas and managing agencies of the city. For collection of the date, it was used directly application of the questionnaire with 20 existing scavengers in points of destination of residues, evaluation of the old place of final destination through the use of the spread sheet of the IQR (Index of Quality of the Residues), developed for the CETESB, identification of the matter dump and photographic register. For effect of treatment of the data, a descriptive analysis with regard to the answers of the interviewed scavengers was carried through. The acquired date, Scale had been according to tabulated and analyzed in Excel 2003, where they had been generated graphical to observe the behavior of the data. The results show that of the twenty interviewed scavengers, 35% possess age between 20 and 30 years; 75% possess incomplete basic education; 60% inhabit in houses of waal or huts (cardboard or wood); 55% do not make use of system of water supply and system of sanitary exhaustion; with regard to income monthly for scavengers, 35% had presented income between R$ 200,00 and R$300,00 and 20% possess income above of R$ 500,00 for possessing another source of income; 80% of the interviewed ones, use some type of equipment of individual protection; In the year of 2009, confirming what it was informed by the State agency of Environment, during the field visit, we evidence that the city of Is Gonçalo do Amarante, currently, destines its residues in Sanitary landfill of São Region Metropolitan of Natal in the District of Massaranduba in the city of Ceará-Mirim, after some interventions of the State Public prosecution service. However, in the district of Guajiru some diggings still exist that today are used as final destination of RCD' s (Residues of Construction and Demolition) of the cities of Natal and São Gonçalo do Amarante, as well as private dumps that are used by scavengers that deviate the final destination (Sanitary landfill) of the residues of the great generators (supermarkets, shopping Center and hotels), with presence of urubus, generating a new ambient problem for the city and the aeroportuária security. Ahead of this scene, the study it suggests viable alternatives for the elimination of the private dumps and for the social situation of the escavengers, aiming at to improve its quality of life and 10 to minimize the ambient impacts caused by the inadequate destination of the solid waste in the community of Guajiru, São Gonçalo do Amarante/RN, being able to contribute so that the public managers carry through action in the handling and the control of the final destination of the urban solid waste

Estudo do potencial poluidor da atividade de revenda de combustíveis líquidos na cidade de Natal (RN): justificativas para a implantação da rotulagem ambiental (Selo Verde)

This work presents the analysis of data collected by Universidade Federal do Rio Grande do Norte and State Public Prosecution Office experts concerning to current situation of liquid fuel resale stations, its forms of storage and its technical apparatus for the performance of primary functions (supply of vehicles) and secondary (car washing, storage of used oil, oil change etc.). The data presented were analyzed in the setting of the city of Natal (RN) and considering its characteristics, potentialities and weaknesses. Thereafter, it was discussed liquid fuels resale pollution potential in the city and legal provisions directed to implementation of Green Seal. The discussion involves three agents: environmental, legal and technical ones, applied to all 110 resale fuel stations which were analyzed

Construção e avaliação térmica de um fogão solar tipo caixa

The present work presents a contribution in the study of modelings of transference of heat for foods submitted to the experimental tests in the considered solar oven, where the best modeling for the beefburger of chicken in study was evaluated, comparing the results, considering this food as a half-infinite(1er object considered model) and,after that, considered the chicken beefburger as a plain plate in transient regimen in two distinct conditions: not considering and another model considering the contribution of the generation term, through the Criterion of Pomerantsev. The Sun, beyond life source, is the origin of all the energy forms that the man comes using during its history and can be the reply for the question of the energy supplying in the future, a time that learns to use to advantage in rational way the light that this star constantly special tax on our planet. Shining more than the 5 billion years, it is calculated that the Sun still in them will privilege for others 6 billion years, or either, it is only in the half of its existence and will launch on the Earth, only in this year, 4000 times more energy that we will consume. Front to this reality, would be irrational not to search, by all means technical possible, to use to advantage this clean, ecological and gratuitous power plant. In this dissertation evaluate the performance of solar cooker of the type box. Laboratory of Solar Energy of the Federal University of the Great River of North - UFRN was constructed by the group (LES) a model of solar stove of the type box and was tested its viability technique, considering modeling foods submitted when baking in the solar oven, the cooker has main characteristic the easiness of manufacture and assembly, the low cost (was used material accessible composition to the low income communities) and simplicity in the mechanism of movement of the archetype for incidence of the direct solar light. They had been proposals modeling for calculations of food the minimum baking time, considering the following models of transference of heat in the transient state: object the halfinfinite, plain plate and the model of the sphere to study the necessary temperature for the it bakes of bread (considering spherical geometry). After evaluate the models of transmission of heat will be foods submitted you the processes of to it bakes of, the times gotten for the modeling with the experimental times of it bakes in the solar oven had been compared, demonstrating the modeling that more good that it portraies the accuracies of the results of the model