43 resultados para principal´s role in entrepreneurship education
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This article describes the Ethics and Citizenship Program, a moral education project developed by the Brazilian government to promote education in ethics and citizenship in Brazilian fundamental and middle schools through four key themes: ethics, democratic coexistence, human rights and social inclusion. Some findings from a research project that investigated whether such a program did in fact promote the ethical and citizenship awareness of participating students are outlined. As an introduction to the paper`s main concerns, the Brazilian socioeconomic context is characterised, followed by a description of the historical background of moral education in Brazil.
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The article explores the relationships between distance education, information and communication technologies and teacher education. Its focus is on the interactive media and its uses in an in-service teacher education program, in Brazil, and on the ways the teachers used the technologies doing their own appropriateness. It departs from the presuppositions of the society of knowledge, that is, the close relationships between new technologies, continuing professional development and social inclusion, arguing that this paradigm is an ideological discourse. The article shows how the teachers have used the technologies in creative ways, calling the attention to the importance of this teachers` abilities as a basic skill to facing the challenges of the society of knowledge itself.
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This study examines the relationship between management accounting and planning profiles in Brazilian companies. The main goal is to understand the consequences of not including a fully structured management accounting scheme in the planning process. The authors conducted a field research among medium and large-sized companies, using a probabilistic sample from a population of 2281 companies. Using analytic hierarchy process (AHP) and statistical cluster analysis, the authors grouped the entities` strategic budget planning processes into five profiles, after which the authors applied statistical tests to assess the five clusters. The study concludes that poor or fully implemented strategic and budget-planning processes relate to the management accounting profiles of the Brazilian organizations studied. (C) 2009 Elsevier Inc. All rights reserved.
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Like ants and termites some species of stingless bees (Meliponini), which are very important pollinators in the tropics, use pheromone trails to communicate the location of a food source. We present data on the communicative role of mandibular gland secretions of Meliponini that resolve a recent controversy about their importance in the laying of such trails. Volatile constituents of the mandibular glands have been erroneously thought both to elicit aggressive/defensive behaviour and to signal food source location. We studied Trigona spinipes and Scaptotrigona aff. depilis (`postica`), two sympatric species to which this hypothesis was applied. Using extracts of carefully dissected glands instead of crude cephalic extracts we analysed the substances contained in the mandibular glands of worker bees. Major components of the extracts were 2-heptanol (both species), nonanal (T. spinipes), benzaldehyde and 2-tridecanone (S. aff. depilis). The effect of mandibular gland extracts and of individual components thereof on the behaviour of worker bees near their nest and at highly profitable food sources was consistent. Independent of the amount of mandibular gland extract applied, the bees overwhelmingly reacted with defensive behaviour and were never attracted to feeders scented with mandibular gland extract or any of the synthetic chemicals tested. Both bee species are capable of using mandibular gland secretions for intra-and interspecific communication of defence and aggression and share 2-heptanol as a major pheromone compound. While confirming the role of the mandibular glands in nest defence, our experiments provide strong evidence against their role in food source signalling.
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Proteins incorporated into phospholipid Langmuir-Blodgett (LB) films are a good model system for biomembranes and enzyme immobilization studies. The specific fluidity of biomembranes, an important requisite for enzymatic activity, is naturally controlled by varying phospholipid compositions. In a model system, instead, LB film fluidity may be varied by covering the top layer with different substances able to interact simultaneously with the phospholipid and the protein to be immobilized. In this study, we immobilized a carbohydrate rich Neurospora crassa alkaline phosphatase (NCAP) in monolayers of the sodium salt of dihexadecylphosphoric acid (DHP), a synthetic phospholipid that provides very condensed Langmuir films. The binding of NCAP to DHP Langmuir-Blodgett (LB) films was mediated by the anionic polysaccharide iota-carrageenan (iota-car). Combining results from surface isotherms and the quartz crystal microbalance technique, we concluded that the polysaccharide was essential to promote the interaction between DHP and NCAP and also to increase the fluidity of the film. An estimate of DHP:iota-car ratio within the film also revealed that the polysaccharide binds to DHP LB film in an extended conformation. Furthermore, the investigation of the polysaccharide conformation at molecular level, using sum-frequency vibrational spectroscopy (SFG), indicated a preferential conformation of the carrageenan molecules with the sulfate groups oriented toward the phospholipid monolayer, and both the hydroxyl and ether groups interacting preferentially with the protein. These results demonstrate how interfacial electric fields can reorient and induce conformational changes in macromolecules, which may significantly affect intermolecular interactions at interfaces. This detailed knowledge of the interaction mechanism between the enzyme and the LB film is relevant to design strategies for enzyme immobilization when orientation and fluidity properties of the film provided by the matrix are important to improve enzymatic activity.
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Mechanisms of leukocyte NADPH oxidase regulation remain actively investigated. We showed previously that vascular and macrophage oxidase complexes are regulated by the associated redox chaperone PDI. Here, we investigated the occurrence and possible underlying mechanisms of PDI-mediated regulation of neutrophil NADPH oxidase. In a semirecombinant cell-free system, PDI inhibitors scrRNase (100 mu g/mL) or bacitracin (1 mM) near totally suppressed superoxide generation. Exogenously incubated, oxidized PDI increased (by similar to 40%), whereas PDIred diminished (by similar to 60%) superoxide generation. No change occurred after incubation with PDI serine-mutated in all four redox cysteines. Moreover, a mimetic CxxC PDI inhibited superoxide production by similar to 70%. Thus, oxidized PDI supports, whereas reduced PDI down-regulates, intrinsic membrane NADPH oxidase complex activity. In whole neutrophils, immunoprecipitation and colocalization experiments demonstrated PDI association with membrane complex subunits and prominent thiol-mediated interaction with p47(phox) in the cytosol fraction. Upon PMA stimulation, PDI was mobilized from azurophilic granules to cytosol but did not further accumulate in membranes, contrarily to p47(phox). PDI-p47(phox) association in cytosol increased concomitantly to opposite redox switches of both proteins; there was marked reductive shift of cytosol PDI and maintainance of predominantly oxidized PDI in the membrane. Pulldown assays further indicated predominant association between PDIred and p47(phox) in cytosol. Incubation of purified PDI (> 80% reduced) and p47(phox) in vitro promoted their arachidonate-dependent association. Such PDI behavior is consistent with a novel cytosolic regulatory loop for oxidase complex (re) cycling. Altogether, PDI seems to exhibit a supportive effect on NADPH oxidase activity by acting as a redox-dependent enzyme complex organizer. J. Leukoc. Biol. 90: 799-810; 2011.
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Galectins are beta-galactoside-binding lectins involved in several biological processes and galectin-3 (Gal-3) is related to modulation of immune and inflammatory responses. This study aimed to evaluate the role of Gal-3 in the life span and biological functions of murine neutrophils during in vitro infection by virulent Toxoplasma gondii RH strain. Inflammatory peritoneal neutrophils (N phi) from C57BL/6 wildtype (WT) and Gal-3 knockout (KO) mice were cultured in the presence or absence of parasites and analyzed for phosphatidylserine (PS) exposure and cell death using Annexin-V and propidium iodide staining, and cell viability by MU assay. Cell toxicities determined by lactate dehydrogenase (LDH), degranulation by lysozyme release, and cytokine production were measured in NO culture supernatants. Phorbol myristate acetate (PMA)- or zymosan-dependent reactive oxygen species (ROS) were measured in N phi cultures. Our results demonstrated that Gal-3 is involved in the increase of the viable Not. number and the decrease of PS exposure and cell death following T. gondii infection. We also observed that Gal-3 downmodulates gondii-induced N phi toxicity as well as N phi degranulation regardless of infection. Furthermore, Gal-3 expression by N phi was associated with increased levels of IL-10 in the beginning and decreased levels of TNF-alpha later on, regardless of parasite infection, as well as with decreased levels of IL-6 and increased IL-12 levels, following early parasite infection. Our results also showed that Gal-3 suppresses PMA- but not zymosan-induced ROS generation in N phi following T. gondii infection. In conclusion, Gal-3 plays an important modulatory role by interfering in N phi life span and activation during early T gondii infection. (C) 2009 Elsevier GmbH. All rights reserved.
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XPC participates in the initial recognition of DNA damage during the DNA nucleotide excision repair process in global genomic repair. Polymorphisms in XPC gene have been analyzed in case-control studies to assess the cancer risk attributed to these variants, but results are conflicting. To clarify the impact of XPC polymorphisms in cancer risk, we performed a meta-analysis that included 33 published case-control studies. Polymorphisms analyzed were Lys939Gln and Ala499Val. The overall summary odds ratio (OR) for the associations of the 939Gln/Gln genotype with risk of cancer was 1.01 (95% confidence interval (95% CI): 0.94-1.09), but there were statistically significant associations for lung cancer, observed for the recessive genetic model (Lys/Lys + Lys/Gln vs Gln/Gln), (OR 1.30; 95% CI: 1.113-1.53), whereas for breast cancer a reduced but nonsignificant risk was observed for the same model (OR 0.87; 95% CI: 0.74-1.01). The results for Ala499Val showed a significant overall increase in cancer risk (OR 1.15; 95% CI: 1.02-1.31), and for bladder cancer in both the simple genetic model (Ala/Ala vs Val/Val) (OR 1.30; 95% CI: 1.04-1.61) and the recessive genetic model (Ala/Ala + Ala/Val vs Val/Val) (OR 1.32; 95% CI: 1.06-1.63). Our meta-analysis supports that polymorphisms in XPC may represent low-penetrance susceptibility gene variants for breast, bladder, head and neck, and lung cancer. XPC is a good candidate for large-scale epidemiological case-control studies that may lead to improvement in the management of highly prevalent cancers.
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The human endometrium is a dynamic tissue that undergoes cycles of growth and regression with each menstrual cycle. Adult progenitor stem cells are likely responsible for this remarkable regenerative capacity; these same progenitor stem cells may also have an enhanced capacity to generate endometriosis if shed in a retrograde fashion. The progenitor stem cells reside in the uterus; however, less-committed mesenchymal stem cells may also travel from other tissues such as bone marrow to repopulate the progenitor population. Mesenchymal stem cells are also involved in the pathogenesis of endometriosis and may be the principle source of endometriosis outside of the peritoneal cavity when they differentiate into endometriosis in ectopic locations. Finally, besides progenitor stem cells, recent publications have identified multipotent stem cells in the endometrium. These multipotent stem cells are a readily available source of cells that are useful in tissue engineering and regenerative medicine. Endometrial stem cells have been used to generate chondrocytes, myocytes, neurons, and adiposites in vitro as well as to replace dopaminergic neurons in a murine model of Parkinson`s disease.
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Although the number of genes known to be associated with bovine spermatogenesis has increased in the past few years, regulation of this biological process remains poorly understood. Therefore, discovery of new male fertility genetic markers is of great value for assisted selection in commercially important cattle breeds, e.g., Nelore, that have delayed reproductive maturation and low fertility rates. The objective of the present study was to identify sequences associated with spermatogenesis that could be used as fertility markers. With RT-PCR, the following five transcripts preferentially expressed in adult testis were detected: TET(656) detected only in adult testis; TET(868) and TET(515) expressed preferentially in adult testis but also detected in fetal gonads of both sexes; and TET(456) and TET(262). expressed primarily in the testis, but also present in very low amounts in somatic tissues. Based on their homologies and expression profiles, we inferred that they had putative roles in spermatogenesis. Detection of sequences differentially expressed in testis, ovary, or both, was a useful approach for identifying new genes related to bovine spermatogenesis. The data reported here contributed to discovery of gene pathways involved in bovine spermatogenesis, with potential for prediction of fertility. (C) 2011 Elsevier Inc. All rights reserved.
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Little is known about the effect of clinical characteristics, parental psychopathology, family functioning, and environmental stressors in the response to methylphenidate in children with attention-deficit/hyperactivity disorder (ADHD) followed up in a naturalistic setting. Data from cultures outside the United States are extremely scarce. This is a longitudinal study using a nonrandom assignment, quasi-experimental design. One hundred twenty-five children with ADHD were treated with methylphenidate according to standard clinical procedures, and followed up for 6 months. The severity of ADHD symptoms was assessed by the Swanson, Nolan, and Pelham rating scale. In the final multivariate model, ADHD combined subtype (P < 0.001) and comorbidity with oppositional defiant disorder (P = 0.03) were both predictors of a worse clinical response. In addition, the levels of maternal ADHD symptoms were also associated with worse prognosis (P < 0.001). In the context of several adverse psychosocial factors assessed, only undesired pregnancy was associated with poorer response to methylphenidate in the final comprehensive-model (P = 0.02). Our study provides evidence for the involvement of clinical characteristics, maternal psychopathology, and environmental stressors in the response to methylphenidate. Clinicians may consider adjuvant strategies when negative predictors are present to increase the chances of success with methylphenidate treatment.
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Background. Foot deformities have been related to diabetic neuropathy progression but their influence on plantar distribution during dynamic tasks is not completely understood. The purpose of the present study was to investigate the influence of metatarsal head prominence and claw toes on regional plantar pressures during gait in patients with diabetic neuropathy Methods Seventy-one adults participated in this study categorized into three groups: a control group (CG, n = 32), patients with diabetic neuropathy without any foot deformities (DG, n = 20), and patients with diabetic neuropathy with metatarsal head prominence and/or claw toes (DMHG, n = 19). Plantar pressure variables (contact area, peak pressure, and maximum mean pressure) were evaluated during gait on rearfoot, midfoot, and forefoot using capacitive insoles (Pedar-X System, Novel Inc., Munich, Germany). A general linear model was applied to repeatedly measure and analyze variance relationships between groups and areas. Results. DMHG. presented larger contact areas at the forefoot and midfoot along with higher peak pressure at the rearfoot compared to the other two groups The DG showed higher mean pressure at the midfoot compared to:the other two groups. Conclusion. The coexistence of diabetic neuropathy and metatarsal head prominence in addition to claw toes, resulted in overloading the rearfoot and enhancing the contact area of forefoot and midfoot while walking. This plantar pressure distribution is a result of a different coordination pattern adopted in order to reduce plantar loads at the anterior parts of the foot that were structurally altered. Patients with diabetic neuropathy without any forefoot deformities presented a different plantar pressure distribution than patients with deformities suggesting that both neuropathy and structural foot alterations can influence foot rollover mechanisms.
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Histoplasma capsulatum (Hc) is a facultative, intracellular parasite of worldwide significance. Infection with Hc produces a broad spectrum of diseases and may progress to a life-threatening systemic disease, particularly in individuals with HIV infection. Resolution of histoplasmosis is associated with the activation of cell-mediated immunity, and leukotriene B(4) plays an important role in this event. Lipid bodies (LBs) are increasingly being recognized as multifunctional organelles with roles in inflammation and infection. In this study, we investigated LB formation in histoplasmosis and its putative function in innate immunity. LB formation in leukocytes harvested from Hc-infected C57BL/6 mice peaks on day 2 postinfection and correlates with enhanced generation of lipid mediators, including leukotriene B(4) and PGE(2). Pretreatment of leukocytes with platelet-activating factor and BLT1 receptor antagonists showed that both lipid mediators are involved in cell signaling for LB formation. Alveolar leukocytes cultured with live or dead Hc also presented an increase in LB numbers. The yeast alkali-insoluble fraction 1, which contains mainly beta-glucan isolated from the Hc cell wall, induced a dose- and time-dependent increase in LB numbers, indicating that beta-glucan plays a signaling role in LB formation. In agreement with this hypothesis, beta-glucan-elicited LB formation was inhibited in leukocytes from 5-LO(-/-), CD18(low) and TLR2(-/-) mice, as well as in leukocytes pretreated with anti-Dectin-1 Ab. Interestingly, human monocytes from HIV-1-infected patients failed to produce LBs after beta-glucan stimulation. These results demonstrate that Hc induces LB formation, an event correlated with eicosanoid production, and suggest a role for these lipid-enriched organelles in host defense during fungal infection. The Journal of Immunology, 2009, 182: 4025-4035.
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Background: Environmental factors may influence the development of allergen sensitization and asthma. The aim of this study was to evaluate the role of endotoxin and allergen exposure in early life as a risk factor for recurrent wheezing. Methods: One hundred and four infants from low-income families, at high risk of asthma, were enrolled at birth. Dust samples were collected from the bedding and bedroom floor within 6 months after birth. Recurrent wheezing was defined as 3 or more wheezing episodes in the past year. Endotoxin was determined by Limulus amebocyte lysate assay, and major indoor allergens were quantitated by ELISA in dust extracts. IgE antibodies were measured by ImmunoCAP at 30 months of age. Results: At 30 months, 51 of the 99 infants who completed the study (51.5%) had recurrent wheezing. Respiratory infection was strongly associated with recurrent wheezing (OR 6.67, 95% CI 1.96-22.72), whereas exclusive breastfeeding for at least 1 month was a protective factor (OR 0.09, 95% CI 0.01-0.51). Exposure to high levels of mouse allergen was more frequent among non-recurrent wheezers, approaching significance (OR 0.12, 95% CI 0.01-1.13; p=0.064). None of the children were sensitized to mouse. Sensitization to mite was found in 26/90 (28.8%) children, with no association with recurrent wheezing. Conclusion: Respiratory infection was strongly associated with recurrent wheezing in the first 30 months of life, in children at high risk of asthma, living in a socially deprived community in Brazil. Copyright (C) 2009 S. Karger AG, Basel
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Taking into account that atherosclerosis is a focal disease and high levels of plasma cholesterol are closely correlated with its pathogenesis, it is a challenge to explain how equal concentrations of cholesterol bathing the endothelium can produce local, rather than global, effects on arteries. The focal distribution of atherosclerotic lesions has been considered to be dependent, at least in part, on hydrodynamic factors. The present study was carried out to further test the hypothesis that these forces are an important localizing factor in rats feeding a hypercholesterolaemic diet and submitted to infra-diaphragmatic aortic constriction. These animals develop a normotensive prestenotic region with laminar blood flow that serves as control for a normotensive poststenotic region with turbulent blood flow. Our findings clearly demonstrated that the combination of turbulent blood flow and low wall shear stress (WSS) in the presence of hypercholesterolaemia and oxidative stress creates conditions to the formation of focally distributed incipient atherosclerotic lesions observed in the poststenotic segment. In contrast, only diffuse fatty streaks could be observed in the normotensive prestenotic segment with laminar blood flow and normal WSS in the presence of hypercholesterolaemia and oxidative stress. Although haemodynamic forces are not by themselves responsible for the pathogenesis of atherosclerosis, they prime the local vascular wall in which the lesion develop. Further studies are required to establish how haemodynamic forces are detected and transduced into chemical signalling by the cells of the artery wall and then converted into pathophysiologically relevant phenotypic changes.