O pro-��lcool e algumas rela����es CTS concebidas por alunos de 6�� s��rie do ensino fundamental

A crescente degrada����o do meio ambiente e o reconhecimento, por parte da sociedade contempor��nea, da exist��ncia de problemas considerados cr��ticos, acentuadamente a quest��o energ��tica, intensifica a preocupa����o em incorporar nas atividades de ensino aspectos da rela����o do ser humano com o ambiente. A necessidade de abordar, durante atividades de ensino de ci��ncias, quest��es relacionadas com a dimens��o valorativa e aspectos da rela����o entre ci��ncia, tecnologia e sociedade passa a ser reconhecida tanto por educadores de maneira geral quanto por especialistas da ��rea, de maneira particular. O movimento Ci��ncia, Tecnologia e Sociedade (CTS) como um conjunto de propostas para o ensino de ci��ncias �� uma conseq����ncia concreta desta tend��ncia. No caso do Brasil s��o poucas as pesquisas em ensino de ci��ncias que exploram essa possibilidade e s��o poucas as experi��ncias em termos de trabalhos em sala de aula que abordam esta quest��o. Este trabalho, realizado entre maio e novembro de 1996, sistematiza os dados coletados em uma classe de 6�� s��rie do ensino fundamental que teve como tema de estudos o Projeto Pro-��lcool. Foi planejado e desenvolvido um conjunto de atividades, utilizando-se de um n��mero bastante diversificado de procedimentos did��ticos. Os resultados de pesquisa indicam que, um trabalho que ofere��a aos alunos oportunidades de discuss��es e reflex��es, a partir de procedimentos e material did��tico diversificado e rico em termos de solicita����es e propostas aos alunos, pode promover a incorpora����o, em sala de aula, de diferentes dimens��es relacionadas com a ci��ncia, tecnologia, sociedade e ambiente.

Arquitetura multiprocessada e reconfigur��vel para a s��ntese de redes de Petri em hardware

Uma arquitetura reconfigur��vel e multiprocessada para a implementa����o f��sica de Redes de Petri foi desenvolvida em VHDL e mapeada sobre um FPGA. Convencionalmente, as Redes de Petri s��o transformadas em uma linguagem de descri����o de hardware no n��vel de transfer��ncias entre registradores e um processo de s��ntese de alto n��vel �� utilizado para gerar as fun����es booleanas e tabelas de transi����o de estado para que se possa, finalmente, mape��-las num FPGA (Morris et al., 2000) (Soto and Pereira, 2001). A arquitetura proposta possui blocos l��gicos reconfigur��veis desenvolvidos exclusivamente para a implementa����o dos lugares e das transi����es da rede, n��o sendo necess��ria a descri����o da rede em n��veis de abstra����o intermedi��rios e nem a utiliza����o de um processo de s��ntese para realizar o mapeamento da rede na arquitetura. A arquitetura permite o mapeamento de modelos de Redes de Petri com diferencia����o entre as marcas e associa����o de tempo no disparo das transi����es, sendo composta por um arranjo de processadores reconfigur��veis, cada um dos quais representando o comportamento de uma transi����o da Rede de Petri a ser mapeada e por um sistema de comunica����o, implementado por um conjunto de roteadores que s��o capazes de enviar pacotes de dados de um processador reconfigur��vel a outro. A arquitetura proposta foi validada num FPGA de 10.570 elementos l��gicos com uma topologia que permitiu a implementa����o de Redes de Petri de at�� 9 transi����es e 36 lugares, atingindo uma lat��ncia de 15,4ns e uma vaz��o de at�� 17,12GB/s com uma freq����ncia de opera����o de 64,58MHz.

Effects of nitrogen ion irradiation on plasma polymerized films produced from titanium tetraiso pro poxide-oxygen-helium mixtures

In this work films were produced by the plasma enhanced chemical vapor deposition (PECVD) of titanium tetraisopropoxide-oxygen-helium mixtures and irradiated with 150 keV singly-charged nitrogen ions (N(+)) at fluences, phi, between 10(14) and 10(16) cm(-2). Irradiation resulted in compaction, which reached about 40% (measured via the film thickness) at the highest fluence. Infrared reflection-absorption spectroscopy (IRRAS) revealed the presence of Ti-O bonds in all films. Both O-H and C-H groups were present in the as-deposited films, but the density of each of these decreased with increasing phi and was absent at high phi, indicating a loss of hydrogen. X-ray photoelectron spectroscopy (XPS) analyses revealed an increase in the C to Ti atomic ratio as phi increased, while the O to Ti ratio hardly altered, remaining at around 2.8. The optical gap of the films, derived from data obtained by ultraviolet-visible spectroscopy (UVS), remained at about 3.6 eV for all fluences except the highest, for which an abrupt fall to around 1.0 eV was observed. For the irradiated films, the electrical conductivity, measured using the two-point method, showed a systematic increase with increasing phi. (c) 2008 Elsevier B.V. All rights reserved.

A pro-inflammatory role of lymphoid cells in acute pleurisy in rats

The effect of viable splenic lymphoid cells and their constituents (filtrate) on carrageenan-induced acute pleurisy was investigated in rats. Suspensions of lymphoid cells administered intravenously to recipients just prior to initiation of pleurisy enhance both the volume of exudate and cell accumulation in the pleural cavity 3 h after the irritation. Similar results were observed when filtrate of disrupted lymphoid cells was injected either 30 or 5 min before the carrageenan, but not when administered 30 min afterwards. Suspensions of bone marrow cells, on the contrary, were ineffective in producing an enhancement of the parameters studied. When administered into the pleural cavity together with carrageenan, the lymphoid cell filtrate augmented the inflammatory response to the irritant. Nevertheless, it was ineffective, per se, to elicit any local change. It is suggested that lymphoid cells may play a pro-inflammatory role in the initiation of the process by enhancing both the fluid and the cellular components of inflammation.

A comparative study of the efficiency of a pro-biotic and the anti-K99 and anti-A14 vaccines in the control of diarrhea in calves in Brazil.

A total of 99 pregnant cows were divided into eight groups submitted to the following treatments: group I (n = 29) consisted of unvaccinated cows whose calves did not receive a probiotic and was used as control. Group II (n = 10) consisted of vaccinated cows whose calves did not receive a probiotic. Groups III, IV and V (n = 10 neach) consisted of vaccinated cows whose calves received a probiotic for 5, 15 and 30 days, respectively. Groups VI, VII and VIII (n = 10 each) consisted of unvaccinated cows whose calves received a probiotic for 5, 15 and 30 days, respectively. Each animal in the vaccinated groups received two 5.0 ml vaccine doses containing pili K99 and A14 of Escherichia coli by the subcutaneous route. The probiotic containing Lactobacillus acidophilus at the dose of 2.0 x 10(8) live cells in 250 ml milk, was administered orally. All animals were observed clinically and bacteriologically and anti-K99 and anti-A14 antibody titers were determined in serum and colostrum. Mean calf weight was measured at birth and at 30 days of age. The results showed that a combination of the vaccine with the probiotic administered for 15 and 30 days was the most efficient treatment for the control of diarrhea.

A petri net based timing model for hardware/software co-design of digital systems

We have recently proposed an extension to Petri nets in order to be able to directly deal with all aspects of embedded digital systems. This extension is meant to be used as an internal model of our co-design environment. After analyzing relevant related work, and presenting a short introduction to our extension as a background material, we describe the details of the timing model we use in our approach, which is mainly based in Merlin's time model. We conclude the paper by discussing an example of its usage. �� 2004 IEEE.

Pro- and anti-inflammatory cytokines produced by human monocytes challenged in vitro with Paracoccidioides brasiliensis

Monocytes and macrophages play a central role in innate and adaptive immune response against systemic fungal infections. Imbalances in suppressor or stimulatory cytokine secretion caused by these cells may influence disease development, microorganism death, and the nature of the adaptive immune response. This study analyzed the monocyte cytokine profiles of healthy individuals challenged with high and low virulent strains of P. brasiliensis and mRNA cytokine expression kinetics by reverse transcription polymerase chain reaction (RT-PCR). Peripheral blood monocytes from healthy volunteers were cultured in vitro with and without virulent (Pb18) or low virulence (Pb265) strains from P. brasiliensis viable yeast cells. Interleukin-1 beta (IL-1��), IL-6, IL-8, IL-10, tumor necrosis factor-alpha (TNF-��), and transforming growth factor-beta (TGF-��1) were measured in culture supernatants by enzyme immunoassay (ELISA), and mRNA cytokine expression was determined by RT-PCR at 0, 4, 8, 12, 18 and 48 hr. Both P. brasiliensis strains induced monocyte production of IL-1��, IL-6, IL-10 and TNF-��. Pb18 induced higher levels of IL-1��, IL-6, and IL-10 than Pb265. IL-8 and TGF-��1 levels were not significantly different from those cultured without stimulus. The mRNA cytokine expression was similar to supernatant cytokines measured by ELISA. In vitro monocyte challenge with virulent P. brasiliensis strain induces earlier and higher levels of pro- and anti-inflammatory cytokines than low virulence strain.

Petri nets teaching in the Mechatronics Engineering course

The current solutions implanted in the majority of manufacturing systems controlled by PLCs were developed through the language of programming known as ladder. Such a language, easily learned and handled, shows to be efficient whenever the system to be implanted does not demand greater complexity of analyses. Bigger systems, presenting characteristics in which resource compartments, parallelism and synchronizing among processes are more frequent, demand the adoption of solutions differentiation. This article presents a teaching experience and practical application of Petri nets in a Mechatronics Engineering graduation course. Copyright �� 2007 IFAC.

Hacia una nueva pol��tica comercial en pro del desarrollo: selecci��n

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Petri nets and autonomous systems: A case study

This work presents the Petri net-based modeling of an autonomous robot's navigation system used for the application of supplies in agriculture. The model was developed theoretically and implemented through the CPNTools software. It simulates the behavior of the robot, capturing environmental characteristics by means of sensors, making appropriate decisions, and forwarding them to the corresponding actuators. By exciting the model using CPNTools it is possible to simulate situations that the robot might undergo, without the need to expose it to real potentially dangerous situations. ��2009 IEEE.