974 resultados para 802.11b


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As Redes da Próxima Geração consistem no desenvolvimento de arquiteturas que viabilizem a continuidade de serviços que proporcionem sempre a melhor conectividade (Always Best Connectivity - ABC) aos usuários móveis com suporte adequado à Qualidade de Experiência (QoE) para aplicações multimídia de alta definição, nesse novo contexto as arquiteturas têm perspectiva orientada a serviços e não a protocolos. Esta tese apresenta uma arquitetura para redes da próxima geração capaz de fornecer acesso heterogêneo sem fio e handover vertical transparente para as aplicações multimídia. A tese considera diferentes tecnologias sem fio e também adota o padrão IEEE 802.21 (Media Independent Handover – MIH) para auxiliar na integração e gerenciamento das redes heterogêneas sem fio. As tecnologias que a arquitetura possui são: IEEE 802.11 (popularmente denominada de WiFi), IEEE 802.16 (popularmente denominada de WiMAX) e LTE (popularmente denominada de redes 4G). O objetivo é que arquitetura tenha a capacidade de escolher entre as alternativas disponíveis a melhor conexão para o momento. A arquitetura proposta apresenta mecanismos de predição de Qualidade de Experiência (Quality of Experience - QoE) que será o parâmetro decisivo para a realização ou não do handover para uma nova rede. A predição para determinar se haverá ou não mudança de conectividade será feita com o uso da inteligência computacional de Redes Neurais Artificiais. Além disso a arquitetura também apresenta um mecanismo de descarte seletivo de pacotes especifico para aplicações multimídia. A proposta é avaliada via simulação utilizando-se o ns-2 (Network Simulator) e os resultados de desempenho são apresentados através das métricas de QoS, de QoE e também visualmente através da exibição de frames dos vídeos transmitidos na arquitetura.

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Usamos uma metodologia experimental para investigar propriedades ópticas e térmicas da oleína de palma (OP), a fração líquida do azeite de palma (Elaies guineensis) obtida por fracionamento natural, com propriedades físicas que diferem apreciavelmente do azeite. Em uma primeira abordagem, estudamos os espectros de absorção e emissão monitorando a modificação dos espectros com o aumento da concentração β-caroteno misturado com OP, o que permitiu encontrar o coeficiente de absorção molar do β-caroteno (ε = 920,802 mol -1.cm-1.L). Este valor é muito baixo em relação aos conhecidos para o β-caroteno diluído em um solvente puro, como o benzeno ou o n-hexano. Experimentos feitos com β-caroteno diluído em hexano nos permitiram medir ε = 117.900 L.mol-1.cm-1, que representa aproximadamente 18% abaixo dos valores reportados na literatura. Em uma segunda abordagem, os espectros de absorção foram usados para medir o coeficiente de absorção da OP, A = 0,028 cm-1 em 532 nm, o comprimento de onda de um laser usado como fonte de excitação no estudo das propriedades térmicas da OP usando a técnica de lente térmica. Neste sentido foi medido também o coeficiente térmico do índice de refração da OP, dn/dt = - 3,821 x 10 -4 °C -1. Estes resultados, associados ao modelo aberrante para estudos de espectroscopia de lente térmica, levaram à medição do coeficiente de difusão, D = 2,19 ± 0,11 x 10-4 cm2/s, e da condutividade térmica, k = 5,96 ± 0,08 W/m°C. Embora as medidas das propriedades térmicas da OP não sejam ainda conhecidas na literatura, observa-se que elas têm as mesmas ordens de grandeza daquelas já conhecidas para outros óleos vegetais que foram relatadas na literatura.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Graft-versus-host disease is observed mainly in recipients of hematopoietic cell transplantation and is expressed by cutaneous or systemic signals and symptoms. Graft-versus-host disease is clinically classified as acute or chronic. Chronic Graft-versus-host disease occurs in up to 70% of hematopoietic cell transplanted patients and its clinical manifestations have important impact on morbidity and quality of life. The authors report an expressive cutaneous, oral and adnexal involvement in a patient with chronic Graft-versus-host disease with multiple lesions of lichenoid and atrophic pattern.

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Objective: Local invasion of bone is a frequent complication of oral squamous cell carcinoma (OSCC). Development of these osteolytic lesions is mediated by osteoclasts. Receptor activation of NF-kappa B ligand (RANKL) signaling, counteracted by osteoprotegerin (OPG), regulates osteoclastogenesis. Previous studies in rodent models have demonstrated that inhibition of RANKL decreases tumor growth and lesions within bone. However, the contributory role of OSCC cells to this disease process has yet to be defined.Methods: RANKL expression was assessed in a panel of OSCC cell lines by qPCR, flow cytometry, and ELISA. Induction of osteoclastogenesis was assessed by co-culture with macrophages or with OSCC-derived conditioned medium. In an animal model of bone invasion, nude mice were injected intratibially with UMSCC-11B cells expressing a RANKL luciferase promoter to detect tumor-derived RANKL activity. Osteolytic lesions were analyzed by X-ray, micro-CT, and histological methods. RANKL expression was assessed in human OSCC tissues by immunohistochemistry.Results: We demonstrated that OSCCs express varied levels of all RANKL isoforms, both membrane-bound and soluble RANKL. Both co-culture and treatment with OSCC-conditioned media induced osteoclastogenesis. In mice, we demonstrated human RANKL promoter activity during bone invasion. Over the course of the experiment, animals suffered osteolytic lesions as RANKL-driven luciferase expression increased with time. After 8 weeks, human-derived RANKL was detected in areas of bone resorption by immunohistochemistry. Similar epithelial RANKL expression was detected in human OSCC tissues.Conclusion: These data demonstrate the ability of OSCCs to produce RANKL, directly altering the tumor microenvironment to increase osteoclastogenesis and mediate local bone invasion. (C) 2012 Elsevier Ltd. All rights reserved.

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The present study aimed to investigate the efficiency of exfoliative cytology by correlating the clinical lesions of oral squamous cell carcinoma (OSCC) with exfoliative cytology and histopathological findings. Cases of OSCC diagnosed between 1984 and 2010 were analyzed. The inclusion criteria for the present study were the availability of detailed clinical findings and a diagnosis of the disease through exfoliative cytology and histopathology. The cases were assessed and assigned scores, which were then submitted to modal expression analysis, which considers the higher frequency scores, thus relating the variables. The cytological findings demonstrated that the majority of the cases had malignant potential. Exfoliative cytology should be used as a supplementary tool for the diagnosis of OSCC, as it enables the early detection of these lesions. However, cytology should not be used as a substitute for histopathological examination.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Individuals with autism are often unable to communicate through speech, and the ones that are able to speak sometimes cannot begin or to maintain a conversation. This article presents a case study that observed the communicative profile of a young student with autism interacting with his teacher during classroom activities using adapted PECS. The results demonstrated that the autistic student enhanced communicative initiatives in the interaction with his teacher, and the augmentative and alternative communication system was a facilitating tool used in the communicative learning process.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

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This paper presents a technique dubbed WiMAX radio link, the IEEE 802.16 was completed in October 2001 and published on April 8, 2002 and is constantly updated, this technology specifies an interface for wireless metropolitan networks (WMAN) and is under control of the WiMAX Forum, which is a group of companies responsible for the dissipation of this technology in the world, the great benefit of this standard is to offer broadband Internet connection in areas where there is no infrastructure such as fiber optics that has a cost higher. The main purpose of this paper is to present the theoretical and technical characteristics of this technology for both the standard for fixed and mobile standard, regulation of frequency bands by the FCC and description of the physical layer, through to basic concepts are used in many other types of radio link and technologies have been adapted and updated for this little-known standard, allowing a greater range and speed, which are specified and differentiate these advancements is one of the contributions of the work done here. After the theoretical conceptualization stage, a real case study has been inserted in this work to demonstrate the effectiveness of this technology deployed. The idea of presenting this case study is linked to a better view of the use of standard in the market, nationwide

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In this paper expounds on the major phases or generations of the evolutionary process of wireless mobile communication, emphasizing their characteristics and changes over time. The main benefit of this process is the rate of data transfer remembering capacity spectral and methods of harnessing and improving its efficiency. The current network today is 4G and the technologies developed over the following requirements of the ITU are: Long Term Evolution Advanced (LTE-Advanced) and WirelessMAN-Advanced as part of the WiMAX IEEE 802.16m also described in this graduate work

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Pós-graduação em Engenharia Elétrica - FEIS

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We present some results of our studies on the relationship between educational processes and subjective processes. The object of our research is the body inserted in the school context in which we analyze tenderness as a field colonized by the dynamics of power. We have observed in the educational process both signs of capture as well as rupture facing the mechanisms of control coming from the market. We identified the implications of the body in the educational process in order to propose the aesthetic paradigm as a reference for educational action.