514 resultados para Nicolau Copérnico
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Mode of access: Internet.
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Mode of access: Internet.
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The dynamic lateral segregation of signaling proteins into microdomains is proposed to facilitate signal transduction, but the constraints on microdomain size, mobility, and diffusion that might realize this function are undefined. Here we interrogate a stochastic spatial model of the plasma membrane to determine how microdomains affect protein dynamics. Taking lipid rafts as representative microdomains, we show that reduced protein mobility in rafts segregates dynamically partitioning proteins, but the equilibrium concentration is largely independent of raft size and mobility. Rafts weakly impede small-scale protein diffusion but more strongly impede long-range protein mobility. The long-range mobility of raft-partitioning and raft-excluded proteins, however, is reduced to a similar extent. Dynamic partitioning into rafts increases specific interprotein collision rates, but to maximize this critical, biologically relevant function, rafts must be small (diameter, 6 to 14 nm) and mobile. Intermolecular collisions can also be favored by the selective capture and exclusion of proteins by rafts, although this mechanism is generally less efficient than simple dynamic partitioning. Generalizing these results, we conclude that microdomains can readily operate as protein concentrators or isolators but there appear to be significant constraints on size and mobility if microdomains are also required to function as reaction chambers that facilitate nanoscale protein-protein interactions. These results may have significant implications for the many signaling cascades that are scaffolded or assembled in plasma membrane microdomains.
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Protein molecular motors, which are natural nano-machines that convert the chemical energy into mechanical work for cellular motion, muscle contraction and cell division, have been integrated in the last decade in primitive nanodevices based on the motility of nano-biological objects in micro- and nano-fabricated structures. However, the motility of microorganisms powered by molecular motors has not been similarly exploited. Moreover, among the proposed devices based on molecular motors, i.e., nanosensors, nano-mechanical devices and nano-imaging devices, biocomputation devices are conspicuously missing. The present contribution discusses, based on the present state of the art nano- and micro-fabrication, the comparative advantages and disadvantages of using nano- and micro-biological objects in future computation devices. (c) 2006 Elsevier B.V. All rights reserved.
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A pesquisa analisou as tendências de formação de professores na perspectiva da educação inclusiva ante as exigências do cotidiano escolar que desde a década de 1990 vem apresentando uma demanda crescente de estudantes com necessidades educacionais especiais nas salas comuns do ensino regular. A inclusão escolar é um processo que depende da combinação de vários fatores, não é responsabilidade apenas do professor. Entretanto, questionamos: Será que os professores estão sendo preparados para pensar nesta perspectiva, de planejar para a diversidade da sala de aula, especialmente na vertente de alunos com deficiência intelectual, de realizar um trabalho em equipe com professores especialistas? A reflexão sobre a formação e a prática de professores na sala de aula inclusiva faz parte do processo de inclusão, ainda em construção. Eis a questão que norteou esta pesquisa, no sentido de revelar impactos das políticas de inclusão escolar nos cursos de formação de professores e na prática docente, revelando conflitos, resistências, contradições, avanços e mecanismos de exclusão implícitos na proposta da inclusão, contribuindo ainda, para a discussão sobre o papel da universidade como locus privilegiado de formação docente. Os resultados da pesquisa apontaram para uma superficialidade na formação de professores na perspectiva da educação inclusiva. A ação investigativa articulou as políticas públicas de formação de professores, as Diretrizes Curriculares Nacionais para as licenciaturas, os dispositivos legais, a sustentação teórica e os instrumentos de investigação para coordenadores, estudantes de Pedagogia e de Letras e professores do Ensino Fundamental em exercício.
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One of the main characteristics of the world that we live in is the access to information and one of the main ways to reach the information is the Internet. Most Internet sites put accessibility problem on a secondary plan. If we try to define this concept (accessibility) we could say that accessibility it’s a way to offer access to information for the people with disabilities. For example blind people can’t navigate on the Internet like usual people. For that reason Internet sites have to put at their disposal ways to make their content known to this people. Accessibility does not refer only at blind people the web accessibility refers to all people who lost their ability to access the Internet sites. The web accessibility includes every disability that stops people with disabilities to access the web sites content like hearing disability, neurological and cognitive. People that have low speed Internet connection or with low performance computers can use the web accessibility.
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Computational Intelligence Methods have been expanding to industrial applications motivated by their ability to solve problems in engineering. Therefore, the embedded systems follow the same idea of using computational intelligence tools embedded on machines. There are several works in the area of embedded systems and intelligent systems. However, there are a few papers that have joined both areas. The aim of this study was to implement an adaptive fuzzy neural hardware with online training embedded on Field Programmable Gate Array – FPGA. The system adaptation can occur during the execution of a given application, aiming online performance improvement. The proposed system architecture is modular, allowing different configurations of fuzzy neural network topologies with online training. The proposed system was applied to: mathematical function interpolation, pattern classification and selfcompensation of industrial sensors. The proposed system achieves satisfactory performance in both tasks. The experiments results shows the advantages and disadvantages of online training in hardware when performed in parallel and sequentially ways. The sequentially training method provides economy in FPGA area, however, increases the complexity of architecture actions. The parallel training method achieves high performance and reduced processing time, the pipeline technique is used to increase the proposed architecture performance. The study development was based on available tools for FPGA circuits.
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In the contemporaneity, due to the implementation of the neoliberal project in which one verifies the withdrawal of the State in regard to the development of social policies, it is observed a new way of responding to the multifaceted expressions of the social issue, which is the emergence and expansion of a supposed "third sector" in society. Thus, the productive restructuring process has led to the deterioration of labor relations, as well as a super exploration of human labor power, also triggering structural unemployment. By being delineated in classist interests, the emergence of the "third sector" brings contradictory aspects to the society, one of these being the very concept of "third sector", more ideological than real. By seeking to answer the expressions of the social issue, demands the intervention of social workers in the institutions that "composes it". This way, arises the interest in researching what are the current conditions and labor relations of the social workers who work in the institutions of the "third sector" in Mossoró-RN. Therefore, this study is constituted by a survey for the conclusion of a Master's degree in Social Service at the Universidade Federal do Rio Grande do Norte. Therefore, it was listed out as general objective to identify and analyze the conditions and labor relations of the social workers entered in the institutions of the "third sector" in Mossoró-RN. And by specific objectives: to map the institutions that are part of the "third sector" in the city of Mossoró, which have social workers on its professional staff, in order to profile the same; and, analyze the main challenges presented to the work of the social worker in these institutions. We used the bibliographic and documental research to enlighten the knowledge of the topic approached and the development of the field research, in which for the analysis of the data obtained, through field research, it was used the quantitative and qualitative approach. The search results confirmed that half of the institutions was identified as philanthropics, and most of them are funded by the federal government and that such organizations develop activities in several areas, particularly health and welfare. Concerning the conditions and labor relations, was highlighted the fact that half of the professionals insert themselves within the institutions by appointment; regarding the salary, 57.1% of employees receive between 3 and 4 minimum wages, which is considered relatively low. Was satisfactory the analysis related to the labor rights, because almost all offer a formal contract, which ensures, in great measure, the effectuation of such rights. Now with regard to the workload, 5 of 6 institutions implemented the Law Nº. 12.317/2010 ensuring 30 hours a week for social workers. However, it were cited many challenges relating the reality of the "third sector" to the conditions and labor relations, among them stands out: the delay of salary and non-salary adjustment; the realization of activities that do not relate to professionals, functions and duties; the development of many activities by a single professional. Two important data are the not incentive to a postgraduate and the charging of the fulfillment of the goals for the professional productivity. Here, it is worth to reflect that, although this study presents elements that provide to identify some aspects of labor relations and conditions of social workers in the "third sector" in Mossoró- RN, as well as some challenges that permeate this space of professional insertion, is meant that there is much to be unveiled, and other studies can later do so in an attempt to a better understanding of the complexity of processes that permeate the "third sector"
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Reverberation is caused by the reflection of the sound in adjacent surfaces close to the sound source during its propagation to the listener. The impulsive response of an environment represents its reverberation characteristics. Being dependent on the environment, reverberation takes to the listener characteristics of the space where the sound is originated and its absence does not commonly sounds like “natural”. When recording sounds, it is not always possible to have the desirable characteristics of reverberation of an environment, therefore methods for artificial reverberation have been developed, always seeking a more efficient implementations and more faithful to the real environments. This work presents an implementation in FPGAs (Field Programmable Gate Arrays ) of a classic digital reverberation audio structure, based on a proposal of Manfred Schroeder, using sets of all-pass and comb filters. The developed system exploits the use of reconfigurable hardware as a platform development and implementation of digital audio effects, focusing on the modularity and reuse characteristics
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The Solidarity Economy is considered in this work as a development option. Talk about it is to think in the workforce as a producer of material wealth and, above all , subjective , therefore it is necessary to take into account that these relations coexist different types of practices that encompass emotions , lifestyles , etc. This research has as an object of study evaluating the effectiveness of public policy for Solidarity Economy, microrregion Angicos / RN, demonstrating how the Solidarity Economy has encouraged the development not only as a driving force for economic growth, but as the expansion capabilities and freedoms. The Solidarity Economy has several definitions, and despite having its origin in the cooperative movement, is a concept under construction. Focused on the discussion of public policy, is now understood as a proposal for employability, either as a generator of employment and income, reflecting its polymorphism. Theories and concepts developed by Amartya Sen is an important analytical tool for understanding the Solidarity Economy as a development strategy. When speaking of instrumental freedoms, Senniana theory contributes to reflection on how participants socioeconomic actions are becoming active agents of change i n their own freedoms. The analysis was based on the discussion of development beyond economic bias, using the lines of the vari ous local stakeholders with PCPR II, p hase 2, for microrregion Angicos / RN, comprising: public managers, technical advisors and beneficiaries of the program rural poverty alleviation. Besides the discussion of the economic organization of the RN and its spatial distribution, the survey brings the result that the Solidarity Economy in microrregion Angicos / RN contributed to the dev elopment as freedom, proving the effectiveness of public policy by allowing an improvement in the quality of life, enabling efetivations, even without major proportions.
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Micro cracking during service is a critical problem in polymer structures and polymer composite materials. Self-healing materials are able to repair micro cracks, thus their preventing propagation and catastrophic failure of structural components. One of the self-healing approaches presented in the literature involves the use of solvents which react with the polymer. The objective of this research is to investigate a procedure to encapsulate solvents in halloysite nanotubes to promote self-healing ability in epoxy. Healing is triggered by crack propagation through embedded nanotubes in the polymer, which then release the liquid sovent into the crack plane. Two solvents were considered in this work: dimethylsulfoxide (DMSO) and nitrobenzene. The nanotubes were coated using the layer-by-layer technique of oppositely charged polyelectrolytes: cetyltrimethylammonium bromide (CTAB) and sodium polyacrylate. Solvent encapsulation was verified by X-ray diffraction (XRD), Fourier transform infrared (FTIR), analysis thermogravimetry (TGA), adsorption and desorption of nitrogen and scanning electron microscopy (SEM). The introduction of the solvent DMSO into the cavity of the nanotubes was confirmed by the techniques employed. However, was not verified with nitrobenzene only promoted clay aggregation. The results suggest that the CTAB reacted with the halloystite to form a sealing layer on the surface of the nanotubes, thus encapsulating the solvent, while this was not verified using sodium polyacrylate.
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This work describes the synthesis and aplication of homogeneous and heterogenized iron catalysts in the alkylation reaction of toluene with propene, empolying experimental design. The homogenous complex was obtained trough the synthesis of the organic ligand folowed by the complexation of the iron(II) chloride. As to the heterogenized complexes, first were synthetized the inorganic supports (SBA-15, MCM-41 and Al-MCM-41). Then, it was synthetized the ligand again, that through funcionalization with chloropropyltrimethoxysilane (CPTMS), was anchored on the support previously calcinated. To these anchored ligands, was complexed the iron(II) chloride, previously solubilizated in tetrahydrofuran (THF). The organic ligand characterization was accomplished trough nuclear magnetic resonance (NMR) and Infrared spectroscopy (IV). The supports were characterized with x-ray diffraction (DRX), texture analysis with nitrogen adsorption/desorption (before and after the anchoring), termogravimetric analysis (TG) and infrared (IV). The metalic content was quantified trough the atomic absorption spectrophotometry (AAS). The complexes were tested in catalytic reactions emolying ethylaluminium sesquichloride (EASC) as co-catalyst in steel reactor, under mecanic stirring. The reaction conditions ranged from 4 to 36 ◦C, with many aluminum/iron ratios. The catalysts were actives in homogeneous and heterogenized ways. The homogenous catalytic complex showed a maximum turnover frequency (TOF) of 8.63 ×103 · h −1 , while, in some conditions, the anchored complexes showed better results, with TOF of until 8.08 ×103 · h −1 . Aditionally, it was possible to determine an equation, to the homogenous catalyst, that describes the product quantity in function of reacional temperature and aluminum/iron ratio.
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This Thesis main objective is to implement a supporting architecture to Autonomic Hardware systems, capable of manage the hardware running in reconfigurable devices. The proposed architecture implements manipulation, generation and communication functionalities, using the Context Oriented Active Repository approach. The solution consists in a Hardware-Software based architecture called "Autonomic Hardware Manager (AHM)" that contains an Active Repository of Hardware Components. Using the repository the architecture will be able to manage the connected systems at run time allowing the implementation of autonomic features such as self-management, self-optimization, self-description and self-configuration. The proposed architecture also contains a meta-model that allows the representation of the Operating Context for hardware systems. This meta-model will be used as basis to the context sensing modules, that are needed in the Active Repository architecture. In order to demonstrate the proposed architecture functionalities, experiments were proposed and implemented in order to proof the Thesis hypothesis and achieved objectives. Three experiments were planned and implemented: the Hardware Reconfigurable Filter, that consists of an application that implements Digital Filters using reconfigurable hardware; the Autonomic Image Segmentation Filter, that shows the project and implementation of an image processing autonomic application; finally, the Autonomic Autopilot application that consist of an auto pilot to unmanned aerial vehicles. In this work, the applications architectures were organized in modules, according their functionalities. Some modules were implemented using HDL and synthesized in hardware. Other modules were implemented kept in software. After that, applications were integrated to the AHM to allow their adaptation to different Operating Context, making them autonomic.
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Camu-camu (Myrciaria dubia H.B.K. (McVaugh)) is a native Amazon fruit, recognized worldwide as one of the main natural sources of ascorbic acid. Due to its great acidity, this fruit is generally consumed after processing into juice or as ingredient in food preparations. As a co-product of the camu-camu processing, a significant amount of agroindustrial residue is generated. Despite the studies showing the bioactive value and biological potential of the fruit, few studies have approached the possible processing techniques, transformation and preservation of camu-camu fruits and its agroindustrial pomace. Therefore, the present work has the objective of evaluating two different drying processes applied to camu-camu pomace (peel and seeds with residual pulp), freeze drying and hot air drying, in order to obtain a functional fruit product. This thesis was divided into three stages: the first one shows the studies related to the freeze drying and hot air drying, where we demonstrated the impact of the selected drying techniques on the bioactive components of camu-camu, taking the fresh pomace as the control group. Among the investigated conditions, the groups obtained at 50ºC and 4 m/s (SC50) and 80ºC and 6 m/s (SC80) were selected as for further studies, based on their ascorbic acid final content and Folin-Ciocalteau reducing capacity. In addition to SC50 and SC80, the fresh pomace (RF) and freeze dried (RL) samples were also evaluated in these further stages of the research. Overall, the results show higher bioactive concentration in the RF samples, followed by RL, SC50 and SC80. On the second step of the research, the antioxidant, antimicrobial and antienzymatic activities were evaluated and the same tendency was observed. It was also reported, for the first time in the literature, the presence of syringic acid in dried camu-camu pomace. In the third and final stage of the research, it was investigated the effect of dried camu-camu on aging and neuroprotective disorders, using the in vivo model C.elegans. It was observed that camu-camu extracts were able to modulate important signaling genes relevant to thermal and oxidative stresses (p < 0.05). The polar acid, polar basic and polar neutral fractions obtained from the low molecular extracts of SC50 were able to extend the lifespan of wild type N2 C. elegans in 20% and 13% (p < 0.001). Results also showed that the paralysis induced by the β1-42 amyloid was significantly (p < 0.0001) retarded in CL4176 worms. Similarly, the camu-camu extracts attenuated the dopaminergic induction associated to Parkinson’s disease. Finally, a global analysis of the data presented here reveal that the camu-camu pomace, a co-product obtained from the industrial processing of a native Brazilian fruit, is a relevant natural source of health relevant compounds. This thesis, shows for the first time, the multifunctionality of camu-camu pomace, a natural resource still underexploited for scientific, commercial and technological purposes.
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This paper suggests modifications in coating of electrodes providing an alternative for execution of welding with low hydrogen electrode AWS E7018 without having to dry it, reducing thus the cost and time of manufacturing of high resistance welds. The welds in this research were developed with basic coated electrodes (hygroscopic) – SMAW process – externally painted with aluminum spray paint for high temperatures or wrapped with thin plastic films (PVC) and aluminum foil films used commonly for food protection. The basic premise is that establishing a barrier between the atmosphere and the electrode coating could reduce the effects of high hygroscopicity presented by coatings of low hydrogen, minimizing this way the main source of supply of hydrogen to the fusion pool during welding. It is also expected that the addition of new materials from the electrode coating to the fusion pool would induce metallurgical changes in the deposited metal and, as a consequence, modifications in its mechanical properties. This research dealt with measuring the dissolved hydrogen in the deposited metal after welding with modified electrodes, evaluating the influence of these changes in the produced microstructures and in the mechanical properties of the resulting weld, and comparing the obtained results with the standard welding procedures and with the recently developed waterproof electrodes. The results obtained in most samples welded with modified electrodes showed increased mechanical resistance and increased tenacity due to the increased percentage of acicular ferrite in metal deposited without significant elevation of hardness, when compared with the traditional welding with AWS E7018 electrode and with ELBRÁS BRH4R waterproof electrode. The diffusing hydrogen measured in the modified electrodes was kept inside the parameters defined by international codes.