Projeto de Up-Down Converter e Antena para Comunicações Wi-Fi Sub-Aquáticas

As ondas de rádio são altamente atenuadas em ambientes sub-aquáticos. Contudo, como essa atenuação aumenta com o aumento da frequência, o uso de baixas frequências permite obter maior distancias de comunicação. A possibilidade de usar cartas Wi-Fi comerciais é extremamente atractiva devido ao seu baixo custo e à sua grande compatibilidade com o protocolo IP, permitindo o uso de Internet em ambientes aquáticos. Há vários cenários de aplicação, entre os quais destaca-se a monitorização ambiental, vigilância marinha, uso em portos marinhos e ainda na industria petrolífera, gas e matéria-prima. Este trabalho prende-se com o desenvolvimento de um sistema de conversão de frequências e de uma antena que permitirá o uso de cartas comerciais Wi-Fi para estabelecer uma comunicação sub-aquática a distâncias maiores. O sistema desenvolvido irá converter o sinal RF da carta Wi-Fi centrado nos canais de 2.4 GHz) para uma frequência IF centrada em 100MHz. Este sinal é o que se propaga pelo ambiente aquático. No lado do receptor o sinal será convertido de volta para a banda Wi-Fi e a comunicação é estabelecida desta forma. O circuito desenvolvido usa um oscilador/PLL, um misturador de frequências, e uma cadeia de amplificação tanto na transmissão tanto na transmissão como na recepção como comutação automática. O projecto inclui a especificação e o desenho da PCB e da antena bem como os resultados obtidos em testes feitos em ambientes reais.Radio-waves are strongly attenuated in an underwater environment. However, as the attenuation increases with frequency, the use of lower frequencies may allow to obtain higher range communications. The possibility to use commercial Wi-Fi cards is extremely attractive due to the low cost and due to its large compatibility with IP protocol, allowing the use of Internet in underwater environment. There are several scenarios of application, among which stand out the environmental monitoring and aquaculture surveillance, sea ports as well as the oil, gas and raw materials industry. The work proposal concerns the development of an up-down converter system and an antenna that will allow the use of commercial Wi-Fi cards to establish an underwater communication with higher ranges. The developed system will downconvert the RF signal from the Wi-Fi card ($\sim$ 2.4GHz) to an IF frequency of around 100MHz. This signal will be the one that propagates through the underwater medium. On the receiver side, this signal will be upconverted to the Wi-Fi band again and the communication is established in this way. The circuit design uses an oscillator/PLL, a mixer, and it has amplification chain in the transmission and reception with automatic switching. The project includes the specification and design of the PCB and the antenna as well as the obtained results in measurements performed in a real field

ESTRUTURA DE MERCADO DE PRODUTOS LÃCTEOS NO MUNICÃPIO DE LAVRAS, MG

This study was carried out with the objective of characterizing the market structure and the commercialization of dairy products in the district of Lavras, MG, Brazil. For such study, agents were identified, their market conduct, and the prices paid and received were analyzed, as well as the volume of sales in the different market segments. It was verified that the products demanding greater technological resources, such as milk “longa vida†( “long-life†or UHT milk ) and milk sweets are the ones that feature the largest commercialization margins. In the retail segment, supermarkets feature, in average, the lowest margins in relation to their competitors, especially “longa vida†milk. In the consumer market of milk, the sterilized product is the most demanded kind with 36% of the total consumption, informal milk (without inspection) with 31% and milk “longa vida†with 28%. The consumers prefer the informal type because they believe it features better quality, price, distribution and payment services. By the Gini Index methodology, it was verified that there is a concentration in the distribution of milk in the wholesale and retail markets, especially in retail stores.Market structure, commercialization, dairy products.,

TANQUES DE EXPANSÃO E RESFRIAMENTO DE LEITE COMO ALTERNATIVA DE DESENVOLVIMENTO REGIONAL PARA PRODUTORES FAMILIARES

The deregulation of the sector occurred in the early 1990 and the globalization of markets have presented a series of injunctions to the productive milk chain, particularly in the primary production stage, imposing to the organizations the need of a wide reformulation of their structures and strategies in order to keep such organisms themselves either active and competitive. This study aims to present the experiences of associative organizations of dairy farmers of six rural communities of the State of Minas Gerais, which have been adopting the system of purchasing and use of communitarian milk cooling tanks. The methodology consisted in the utilization of qualitative and quantitative research methods through an exploratory study, a descriptive approach and a comparative multicase study. The statistical analyses of frequency and distinguishers were used. It was found that that 82% of the farmers interviewed stated that the need of installation of the communitarian tank was the chief reason for them to associate, which is highly justifiable, considering the transformations which have been occurring in that productive chain. Out of the motivational variables indicating the associative behavior which have most discriminated the communities it stand out the demand for the dairy plant, the power of bargain in milk price and in the purchase of inputs, the reduction of the transportation cost and the commitment to the MAPA guidelines. The results showed that the associative experiences of the dairy farmers in the purchasing of milk cooling tanks vary according to the participation of the local industry – whether a dairy plant whether an agricultural cooperative, as well as public bureaus.milking, associativism, expanding tanks, milk cooling tanks.,

Central nervous system lymphoma: iconographic essay

The authors illustrate the present pictorial essay about central nervous system lymphoma with magnetic resonance images obtained in their institution over the past 13 years. Some of the main radiological findings in primary and secondary presentations of this type of lymphoma are discussed. Central nervous system lymphoma is a relatively uncommon tumor, but magnetic resonance imaging findings may suggest the diagnosis.Ilustramos este ensaio iconográfico de linfoma do sistema nervoso central com imagens de ressonância magnética obtidas em nosso serviço nos últimos 13 anos e discutimos algumas das principais características radiológicas deste tipo de linfoma, primário e secundário. O linfoma sistema nervoso central é um tumor relativamente infrequente, mas alguns achados na ressonância magnética podem sugerir este diagnóstico.11011

Arquitetura sem truques: Bairro de Santa Maria e Bairro da Prageira, as HE em Peniche, por Vítor Figueiredo

O presente estudo centra-se na produção arquitetónica da habitaçãoprogramada em Portugal, nomeadamente sobre os programas deCasas de Renda Económica e Casas dos Pescadores, promovidos pelas«Habitações Económicas» -Federação de Caixas de Previdência [HE] emmeados do século XX. Tem como objeto de estudo o bairro de Casas deRenda Económica de Santa Maria e o bairro dos Pescadores da Prageira,ambos situados em Peniche, construídos no início da década de 1970 eprojetados por Vítor Figueiredo. O enquadramento histórico do organismo,as motivações para a sua fundação e o seu desenvolvimento emPortugal, juntamente com o estudo histórico e sociográfico de Peniche naépoca da construção dos conjuntos habitacionais, são fundamentais parauma melhor compreensão dos objetos de estudo.Por outro lado, é pertinente e necessário, para um melhor entendimentoda resposta arquitetónica de Vítor Figueiredo em ambos os bairros,conhecer mais a fundo a sua visão, interpretação e fundamento na produçãode arquitetura de cariz social.A razão da escolha dos objetos desta pesquisa prende-se com aoportunidade de estudar dois projetos desenvolvidos na mesma cidade,para o mesmo organismo e pelo mesmo arquiteto, mas para realidadesdistintas. A forma como as obras foram assimiladas pelos moradores, bemcomo o estudo, a análise e interpretação documental dos projetos destesconjuntos habitacionais, é a finalidade desta pesquisa. Com a análise dacaracterização social de cada bairro, pretende-se perceber qual o impactosocial na construção dos conjuntos e o porquê das soluçõesarquitetónicas.The present study focuses on the architectural production of socialhousing in Portugal, on the framework of Casas de Renda Económica andCasas dos Pescadores, programmes included on the state organism of«Habitações Económicas» - Federação de Caixas de Previdência [HE], inthe mid 20th century, having as its base project the residential area of lowincome economic houses of Santa Maria and the residential area ofPescadores da Prageira, in Peniche, and built at the starts of the 70s, bothprojected by Vítor Figueiredo. The historical framework of this organism,the motivations for its foundations and its development in Portugal, alongwith the historic and sociographic study of Peniche at the time of buildingthe housing complex, are vital for a better understanding of the studyobjects.On the other hand, it is relevant and required, to fully understandthe architectural answer of Vítor Figueiredo in both residential areas, toget to know, in a deeper sense, his vision, interpretation and reasoningprinciples in the production of architecture of social nature.The reason for choosing these objects in this research is the opportunityof studying two projects in the same city, for the same organism andby the same architect but for different realities. The way as the constructionworks were handled by the residents, as well as the study, analysis anddocumental interpretation of these housing complexes projects, is the actualaim of this research. With the analysis of the social characterization ofeach residential area, it is intended to understand the social impact in thebuilding of the complexes and its architectural solutions

Assessment of Wild Rocket (Diplotaxis tenuifolia (L.) DC.) Germplasm accessions by NGS identified SSR and SNP markers

Rocket is the common designation for two baby-leaf salad crops of the Brassicaceae family: Eruca sativa (L.) Cav., usually referred to as annual garden rocket, and Diplotaxis tenuifolia (L.) DC. commonly named to as perennial wild rocket. E. sativa is used for human consumption since antiquity. However, the growing consumer preference for D. tenuifolia is being accompanied by the fast increase in its production area and commercialization of new cultivars. Nevertheless, the worldwide number of wild rocket accessions maintained in germplasm collections is very reduced, the solution for which situation the project “REMIRucula” intends to contribute, establishing a germplasm collection at the INIAV, Oeiras, Portugal. Herein, we report on the establishment via next generation sequencing (NGS) of the first genome assembly of D. tenuifolia and the identification of specific single sequence repeat (SSR) and single nucleotide polymorphisms (SNP) loci for the establishment of specific DNA-markers for this species. A representative set of 87 D. tenuifolia and 3 E. sativa accessions were assessed by 5 SSR and 9 SNP-CAPS markers, allowing a drastic discrimination between both species and the establishment of unequivocal molecular fingerprints for the analyzed accessions. The non-discrimination within six pairs and one trio of D. tenuifolia accessions is discussed.info:eu-repo/semantics/publishedVersio

CUSTOS DE PRODUÇÃO DA ATIVIDADE LEITEIRA NA REGIÃO SUL DE MINAS GERAIS

The production costs for dairy milk in the southern region of the state of Minas Gerais are presented in this study. This research identifies economic indexes of costs that most influence decisions made by milk producers. The research is based on the theory of costs and the study location was the southern region of the state of Minas Gerais, where data on the 12 milk production units were gathered from March of 2000 to February of 2001, characterizing a multicase study. The economic analysis proved that milk prices were below average total cost but exceeded average variable cost. Even though profits may be negative in this case, as long as variable cost gets covered, the profit-maximizing decision is to continue production. Thus, not all of the fixed costs are lost. The research shows that expenses on variable resources represent the greater portion of the final cost of milk, like costs with cattle feed and labor. The items with fixed costs which affected most on the cost of milk production in the south of Minas Gerais were machinery and equipment.production costs, milk, south of Minas Gerais.,

EFICIÊNCIA ECONÔMICA NA CULTURA DO CAFÉ: UM ESTUDO NO SUL DE MINAS GERAIS

This paper has sought to evaluate the economical efficiency in the use of productive resources in the coffee production in the south region of the state of Minas Gerais. Economical efficiency was estimated through a production frontier function using a sample of 43 coffee producers. The average economical efficiency index reached by the coffee producers in the south of Minas Gerais was 80,14%. Such index indicates that a tendency to gains in productions can be obtained through a better allocation of the production factors, which may lead them to operate on the production frontier line.production frontier, economical efficiency, coffee., Production Economics, Crop Production/Industries,

Postcosecha de maracuyá amarilla cosechada temprano en regiones tropicales de tierras altas

As baixas temperaturas próximas a maturação plena dos frutos inviabilizam o cultivo do maracujá em regiões tropicais de altitude. Visando definir a possibilidade de colheita antecipada, objetivou-se avaliar a qualidade pós-colheita de frutos colhidos antecipadamente (casca verde), com e sem tratamento com ethephon, visando o aproveitamento dos frutos antes da chegada do inverno. Para isto, determinou-se sólidos solúveis (SS), pH, acidez titulável (AT), ratio, perda de massa, rendimento de polpa, espessura e índice de cor da casca (ICC) e polpa (ICP), produção de CO2 e etileno. O delineamento experimental foi inteiramente casualizado em esquema fatorial com frutos tratados ou não com etileno e cinco períodos do armazenamento. Frutos imersos em ethephon apresentaram cor da casca 100% amarela após 14 dias (três dias antes do tratamento controle). Cor da polpa, espessura da casca, perda de massa e pH não diferiram entre os tratamentos, bem como AT, SS e ratio apresentaram semelhanças. O rendimento de polpa obedeceu ao nível requerido pela indústria em ambos os casos. Com isto, frutos de maracujá-amarelo podem ser colhidos antecipadamente sem perdas significativas das características comerciais e propiciando sua comercialização em áreas marginais a cultura.Low temperatures near full ripening of fruits bring about unfeasibility of passion fruit cultivation at tropical high-altitude regions. Aiming at defining the possibility of harvesting the fruits in advance, the current research was proposed to assess postharvest-quality of passion fruits at a green-peel phenological stage under influence of treatments with and without ethephon application so that the fruits might be consumed shortly before winter season. For such, soluble acids (SS), titratable acidity (AT), ratio, loss of mass, pulp yield, thickness and color index of peel (ICC) and pulp (ICP), carbon dioxide emissions, and ethylene production were determined herein. The experimental design was completely randomized in factorial scheme with fruits both treated with and without ethylene along with five storage periods. Fruits immersed into ethylene showed peel color 100% yellow after 14 days-time (three days after application of the control treatment). Pulp color, peel thickness, loss of mass and pH did not differ among treatments, as well as AT, SS and ratio evidenced similarities in terms of physiological responses. Yield pulp met the standards required by the industry under the influence of both treatments. As a result, yellow passion fruits might be harvested in advance bereft of any significant detrimental impacts on commercial characteristics in such a way as to promoting its commercialization at marginal regions amenable to the crop.Las bajas temperaturas cercanas a la plena madurez de las frutas hacen que sea inviable cultivar maracuyá en regiones tropicales de altitud. Con el reto de definir la posibilidad de una cosecha temprana, el objetivo fue evaluar la calidad poscosecha de las frutas cosechadas temprano (cáscara verde), con y sin tratamiento con ethephon, con el objetivo de utilizar la fruta antes de la llegada del invierno. Para esto, sólidos solubles (SS), pH, atio, acidez titulable (AT), pérdida de masa, rendimiento de pulpa, espesor e índice de color de la cáscara (ICC) y pulpa (ICP), producción de CO2 y etileno. El diseño experimental fue completamente al azar en un esquema factorial con frutas tratadas o no con etileno y cinco períodos de almacenamiento. Las frutas sumergidas en ethephon presentaran un color de piel 100% amarillo después de 14 días (tres días antes del tratamiento de control). El color de la pulpa, el grosor de la cáscara, la pérdida de peso y el pH no difirieron entre los tratamientos, así como la AT, SS y ratio mostraron similitudes. El rendimiento de la pulpa estuvo al nivel requerido por la industria en ambos los casos. Con esto, se puede cosechar los frutos de maracuyá amarillo por adelantado sin una pérdida significativa de características comerciales y proporciando su comercialización en áreas marginales al cultivo