1,222 research outputs found
Desigualdades sociais e acesso seletivo ao ensino superior no Brasil no período 1994-2001
O ensino superior no Brasil experimentou um significativo processo de expansão, iniciado em meados da década de 90. A retomada do crescimento do número de matrículas, após um período de estagnação na década anterior, ocorreu num contexto de aumento do número de concluintes do nível médio, e acentuou-se a partir de 1997, sob os efeitos das políticas governamentais para a ampliação da oferta de vagas. O setor privado foi o principal responsável pelo processo de expansão, em vista da redução das restrições legais para a criação de novos cursos e instituições. Este trabalho investiga as relações entre as chances de ingresso e o risco de evasão e algumas características sociais e familiares dos estudantes, no contexto da expansão recente deste nível de ensino no Brasil. A análise foi baseada nos dados da Pesquisa Mensal do Emprego do IBGE de 1994 a 2001. Os resultados indicam que tanto o ingresso quanto a evasão são fortemente condicionados pelas características sociais dos estudantes, que as chances de ingresso reduziram-se para o conjunto dos concluintes do ensino médio e que o risco de evasão manteve-se constante. Também não foram observadas alterações nas desigualdades de acesso entre estudantes de diferentes grupos sociais no período
A LOW COST PACKAGE FOR THE ANALYSIS OF HUMAN BODY KINEMATICS
The application of the analytical methods of Classical Mechanics has made possible the modelling and quantification of relatively simple motional situations. Only recently, however, with the development of computer integrated systems of kinematic data acquisition and processing, has this branch of Biomechanics acquired a lively momentum. The data for the study of the kinematics of human movement has essentially been obtained with techniques of goniometry, accelerometry and cine- and videophotogrammetry and then processed to provide information on the time histories of the co-ordinates of representative points on the surface of the body. This processing can be done automatically by data acquisition systems such as the Peak Performance, the Elite Motion Analyser, the MacReflex System Motion Analysis System and the Ariel Performance Analysis System (APAS), systems which are, however, far too expensive for the great majority of the researchers and field workers. We have developed a simple and portable PC computer software package which provides facilities for image processing such as the use of several filtering and zooming schemes, image conversion, as well as adjustment of brilliance and contrast. The images are recorded with a video camera and stored frame by frame on disc with a frame grabber and are interactively edited for processing. The image resolution may vary from 800 x 600 pixels with 65 536 colours to 1024 x 768 pixels and 256 colours. The package also includes the means for the acquisition of the co-ordinates of relevant marker points on the body segments and for their export to another package we have developed (Ferreira & Correia da Silva. 1991) which is capable of quantifying the kinematics of the body movement as well as of simulating alternative segment trajectories. Reference: Ferreira. C. & K.Correia da Silva(1991). "John- a Three- Dimensional Model for the Simulation of Human Movement". Proc. First Congress on Computer Science and New Technologies, Malaga
Jack bean (Canavalia ensiformis) urease induces eicosanoid-modulated hemocyte aggregation in the Chagas' disease vector Rhodnius prolixus
AbstractUreases are multifunctional proteins that display biological activities independently of their enzymatic function, such as induction of exocytosis and insecticidal effects. Rhodnius prolixus, a major vector of Chagas' disease, is a model for studies on the entomotoxicity of jack bean urease (JBU). We have previously shown that JBU induces the production of eicosanoids in isolated tissues of R. prolixus. In insects, the immune response comprises cellular and humoral reactions, and is centrally modulated by eicosanoids. Cyclooxygenase products signal immunity in insects, mainly cellular reactions, such as hemocyte aggregation. In searching for a link between JBU's toxic effects and immune reactions in insects, we have studied the effects of this toxin on R. prolixus hemocytes. JBU triggers aggregation of hemocytes after injection into the hemocoel and when applied to isolated cells. On in vitro assays, the eicosanoid synthesis inhibitors dexamethasone (phospholipase A2 indirect inhibitor) and indomethacin (cyclooxygenase inhibitor) counteracted JBU's effect, indicating that eicosanoids, more specifically cyclooxygenase products, are likely to mediate the aggregation response. Contrarily, the inhibitors esculetin and baicalein were inactive, suggesting that lipoxygenase products are not involved in JBU's effect. Extracellular calcium was also necessary for JBU's effect, in agreement to other cell models responsive to ureases. A progressive darkening of the medium of JBU-treated hemocytes was observed, suggestive of a humoral response. JBU was immunolocalized in the cultured cells upon treatment along with cytoskeleton damage. The highest concentration of JBU tested on cultured cells also led to nuclei aggregation of adherent hemocytes. This is the first time urease has been shown to affect insect hemocytes, contributing to our understanding of the entomotoxic mechanisms of action of this protein
Electrolytic Treatment And Biosurfactants Applied To The Conservation Of Eugenia Uniflora Fruit
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Microorganisms are the primary responsible for food poisoning and food spoilage. The purpose of this study was to evaluate different fruit washing methods with tap water, electrolyzed water and rhamnolipids solution produced by Pseudomonas aeruginosa LBI, in order to inhibit microbial growth. The tested organism was Eugenia uniflora. The fruits were washed and periodically inoculated into culture media to evaluate and count the colonies on the fruit surface. It was also observed the deterioration level of the fruits after each treatment. The results showed that treatment with rhamnolipids were the most efficient, inhibiting the growth of fungi and bacteria. The electrolyzed water proved to be very efficient in bacterial inhibition at the initial time, but in the final time it did not present any inhibitory effect. The electrolyzed water was also not effective in eliminating fungus. Washing with tap water was the less efficient treatment of all. The only treatment that showed an increased durability has been with rhamnolipids, increasing shelf life by up to two days. Thus rhamnolipids are the most recommended method for fruits sanitation. © 2016, Sociedade Brasileira de Ciencia e Tecnologia de Alimentos, SBCTA. All rights reserved.363456460CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES
The DNA damage response is developmentally regulated in the African trypanosome
Genomes are affected by a wide range of damage, which has resulted in the evolution of a number of widely conserved DNA repair pathways. Most of these repair reactions have been described in the African trypanosome Trypanosoma brucei, which is a genetically tractable eukaryotic microbe and important human and animal parasite, but little work has considered how the DNA damage response operates throughout the T. brucei life cycle. Using quantitative PCR we have assessed damage induction and repair in both the nuclear and mitochondrial genomes of the parasite. We show differing kinetics of repair for three forms of DNA damage, and dramatic differences in repair between replicative life cycle forms found in the testse fly midgut and the mammal. We find that mammal-infective T. brucei cells repair oxidative and crosslink-induced DNA damage more efficiently than tsetse-infective cells and, moreover, very distinct patterns of induction and repair of DNA alkylating damage in the two life cycle forms. We also reveal robust repair of DNA lesions in the highly unusual T. brucei mitochondrial genome (the kinetoplast). By examining mutants we show that nuclear alkylation damage is repaired by the concerted action of two repair pathways, and that Rad51 acts in kinetoplast repair. Finally, we correlate repair with cell cycle arrest and cell growth, revealing that induced DNA damage has strikingly differing effects on the two life cycle stages, with distinct timing of alkylation-induced cell cycle arrest and higher levels of damage induced death in mammal-infective cells. Our data reveal that T. brucei regulates the DNA damage response during its life cycle, a capacity that may be shared by many microbial pathogens that exist in variant environments during growth and transmission
On spin-1 massive particles coupled to a Chern-Simons field
We study spin one particles interacting through a Chern-Simons field. In the
Born approximation, we calculate the two body scattering amplitude considering
three possible ways to introduce the interaction: (a) a Proca like model
minimally coupled to a Chern-Simons field, (b) the model obtained from (a) by
replacing the Proca's mass by a Chern-Simons term and (c) a complex
Maxwell-Chern-Simons model minimally coupled to a Chern-Simons field. In the
low energy regime the results show similarities with the Aharonov-Bohm
scattering for spin 1/2 particles. We discuss the one loop renormalization
program for the Proca's model. In spite of the bad ultraviolet behavior of the
matter field propagator, we show that, up to one loop the model is power
counting renormalizable thanks to the Ward identities satisfied by the
interaction vertices.Comment: 14 pages, 5 figures, revte
Firing temperature determination and thermoluminescence dating of a brick with cuneiform characters found in the ruins of Ancient Babylon
Este artigo tem por objetivo estudar um tijolo com inscrições em caracteres cuneiformes cujas sentenças estão praticamente completas. Estudos tipológicos correspondentes aos relatos históricos sugerem que o tijolo foi manufaturado no século VI a.C., durante a dinastia de Nabucodonosor II, grande monarca da Babilônia. A amostra foi estudada através da difração de raios X (DRX), ressonância paramagnética de elétron (RPE), termoluminescência (TL) e técnicas de análise por ativação instrumental com nêutrons (AAIN). Os resultados demonstraram que o tijolo tem 2350 anos de idade (± 40) e queima menor que 400o C.This paper aims to study a brick with inscriptions in cuneiform characters in which the sentences are almost complete. Typological studies in agreement with historical records suggest that the tablet was manufactured in the 6th century BCE during the dynasty of Nebuchadnezzar II, Great King of Babylon. The sample was studied by X-ray diffraction analysis (XRD), electron paramagnetic resonance (EPR), thermoluminescence (TL), and instrumental neutron activation analysis (INAA) techniques. The results showed that the brick is 2350 years old (± 40) and its firing temperature was lower than 400 °C
3α,4α-Epoxy-5α-androstan-17β-yl acetate
The title compound, C21H32O3, results from modifications of the A and D rings of the aromatase substrate androstenedione. Ring A adopts a conformation between 10β-sofa and 1α,10β half-chair. Rings B and C are in slightly flattened chair conformations. Ring D approaches a 13β-envelope conformation, probably due to the acetoxy substituent, and shows a very short Csp
3—Csp
3 bond next to the epoxide ring, which is characteristic of 3–4 epoxides.
Reproductive aspects of Macrobrachium amazonicum (Decapoda: Palaemonidae) in the State of Amapá, Amazon River mouth
Sustainability-focused international PBL project:Rethinking digital education for individuals of low socioeconomic status
Providing access to education for individuals of lower socio-economic status is a significant way to reduce poverty, as it
empowers them to grow as professionals and as individuals. Although there is an increasing sense of urgency to promote
these changes, notably motivated by the Sustainable Development Goals (SDGs) set by the UN 2030 Agenda, there are still
few successful ways to solve this problem on a large-scale. As digital technology develops and affordability increases, new
ways to share quality educational content are created. In an exploratory case study, with a qualitative approach, this paper
presents the development of a digital application focused on providing quality educational content directed to vulnerable
groups that lack access to formal learning experiences, specifically focused on waste pickers in Brasilia, Brazil. The main
data collection methods used to make the decisions through the development process were observation, surveys, and
interviews. Within the framework of Problem Based Learning (PBL) an international cross-disciplinary collaboration among
different universities, the project, denominated “Mobile Education”, involved: (i) the design and implementation of a system
consisting of both a web and mobile application; (ii) the research of a viable business model to provide long-term
sustainability for the project; (iii) and the creation of a pilot course of financial education for the preliminary target group,
i.e., waste pickers from Brasilia, Brazil. Conclusively, the project aims to positively impact social transformation for individuals
who work at the Waste Sorting facilities and lack financial knowledge. The Mobile Education project resulted in a functional
version of the app (Web and Mobile) as well as the delimitation of a viable business model to keep it providing digital
equality in Brazilian education
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