920 resultados para zone of proximal development


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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

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Cats are the definitive hosts of Toxoplasma gondii. Infected cats excrete oocysts in their feces, infecting humans and other animals. The objective of the present study was to determine the presence of anti-Toxoplasma antibodies in cat owners and their pets, and determine if there was a relationship between Toxoplasma infection and humans who live with infected cats. IgG anti-Toxoplasma antibodies in sera of 59 cat owners were determined by enzyme-linked immunosorbent assay (ELISA), in 24 sera from their cats, IgG, IgM, and IgA antibodies were found using Burney's ELISA. Thirty-eight (64%) of 59 cat owners were positive to IgG anti-Toxoplasma. Seropositivity for cats was 70.8% IgG, 8.3% IgM, and 62.5% IgA. Cohabitation with cats infected by T. gondii, feeding with leftovers or raw viscera, and lack of control over how their feces were handled are risk factors conducive for humans to become infected by T. gondii.

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Loxosceles laeta spiders were captured in the West zone of São Paulo City, this being the first record of the specie in this area. Since loxoscelism is an important public health problem in the South region of Brazil, it is necessary to investigate the presence of this spider in São Paulo City.

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INTRODUCTION: A seroepidemiological survey was carried out to evaluate Trypanosoma cruzi infection in an endemic area of the State of Rio Grande do Norte, Brazil, involving rural residents. METHODS: Sixteen municipalities were randomly selected, 15 from the west mesoregion and one from the central, with an estimated population of 83,852 individuals. A total of 1,950 blood samples were collected in the west mesoregion and 390 in Caicó. Anti-T. cruzi antibodies were detected using the Chagatest® ELISA HAI-hemagglutination kits and indirect immunofluorescence. As sera presented indeterminate results, TESAcruzi® western blot was performed to confirm reactivity. RESULTS: An estimated seroprevalence of 6.5% was determined for the west mesoregion and 3.3% for Caicó. Seropositivity rises progressively with the age of individuals, up to 40 years in Caicó and up to 50 years in the west mesoregion. Only educational level and knowledge regarding the triatomine were associated with seropositivity. No seroreactive individuals under 18 years of age were identified. CONCLUSIONS: Infection by T. cruzi remains high and is concentrated in municipalities in the central western area of the west mesoregion; however, evidence suggests a decline in vector transmission in this mesoregion and in Caicó. Epidemiological variables appear not to influence seropositivity, with the exception of education and knowledge concerning the triatomine, among seroreactive individuals from the west mesoregion.

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In Brazil, more than 99% of malaria cases are reported in the Amazon, and the State of Amazonas accounts for 40% of this total. However, the accumulated experience and challenges in controlling malaria in this region in recent decades have not been reported. Throughout the first economic cycle during the rubber boom (1879 to 1912), malaria was recorded in the entire state, with the highest incidence in the villages near the Madeira River in the Southern part of the State of Amazonas. In the 1970s, during the second economic development cycle, the economy turned to the industrial sector and demanded a large labor force, resulting in a large migratory influx to the capital Manaus. Over time, a gradual increase in malaria transmission was observed in peri-urban areas. In the 1990s, the stimulation of agroforestry, particularly fish farming, led to the formation of permanent Anopheline breeding sites and increased malaria in settlements. The estimation of environmental impacts and the planning of measures to mitigate them, as seen in the construction of the Coari-Manaus gas pipeline, proved effective. Considering the changes occurred since the Amsterdam Conference in 1992, disease control has been based on early diagnosis and treatment, but the development of parasites that are resistant to major antimalarial drugs in Brazilian Amazon has posed a new challenge. Despite the decreased lethality and the gradual decrease in the number of malaria cases, disease elimination, which should be associated with government programs for economic development in the region, continues to be a challenge.

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This study presents an experimental program to assess the tensile strain distribution along prestressed carbon fiber reinforced polymer (CFRP) reinforcement flexurally applied on the tensile surface of RC beams according to near surface mounted (NSM) technique. Moreover, the current study aims to propose an analytical formulation, with a design framework, for the prediction of distribution of CFRP tensile strain and bond shear stress and, additionally, the prestress transfer length. After demonstration the good predictive performance of the proposed analytical approach, parametric studies were carried out to analytically evaluate the influence of the main material properties, and CFRP and groove cross section on the distribution of the CFRP tensile strain and bond shear stress, and on the prestress transfer length. The proposed analytical approach can also predict the evolution of the prestress transfer length during the curing time of the adhesive by considering the variation of its elasticity modulus during this period.

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In this study, the macro steel fiber (SF), carbon fiber (CF) and nano carbon black (NCB) as triphasic conductive materials were added into concrete, in order to improve the conductivity and ductility of concrete. The influence of NCB, SF and CF on the post crack behavior and conductivity of concrete was explored. The effect of the triphasic conductive materials on the self-diagnosing ability to the load–deflection property and crack widening of conductive concrete member subjected to bending were investigated. The relationship between the fractional change in surface impedance (FCR) and the crack opening displacement (COD) of concrete beams with conductive materials has been established. The results illustrated that there is a linear relationship between COD and FCR.

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This paper analyses the impact of elections on the dynamics of human development in a panel of 82 countries over the period 1980-2013. The incidence of partisan and political support effects is also taken into account. A GMM estimator is employed in the empirical analysis and the results point out to the presence of an electoral cycle in the growth rate of human development. Majority governments also influence it, but no clear evidence is found regarding partisan effects. The electoral cycles have proved to be stronger in non-OECD countries, in countries with less frequent elections, with lower levels of income and human development, in presidential and non-plurality systems and in proportional representation regimes. They have also become more intense in this millennium.

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Las bacterias que habitan la rizosfera y que poseen la capacidad de provocar un efecto positivo sobre las plantas son denominadas en su conjunto como Rizobacterias Promotoras del Crecimiento Vegetal (PGPR). Estas bacterias han desarrollado diferentes estrategias para adaptarse a diversas condiciones ambientales. La capacidad para responder a variaciones en la disponibilidad nutricional permite la persistencia de la bacteria en el suelo y mejora sus posibilidades para colonizar la planta hospedadora. En la naturaleza, a menudo las bacterias se encuentran en estructuras de comunidades de microorganismos interconectados denominados biofilms, con un estilo de vida diferente al de la vida en forma planctónica. La formación del biofilm podría representar una estrategia de supervivencia de la rizobacteria a condiciones adversas del suelo. Por Microscopía Confocal de Barrido Láser (CLSM), hemos observado que Rhizobium leguminosarum desarrolla un biofilm característico sobre una superficie abiótica. Hemos identificado algunos de los factores genéticos que influyen en su formación. El presente proyecto propone avanzar en el conocimiento de los factores ambientales y genéticos que influyen sobre la capacidad de las rizobacterias para formar biofilms y su impacto en la interacción con las plantas. A través de enfoques genéticos (mutacionales y de expresión génica) y análisis por CLSM nos proponemos acercarnos a un modelo de los factores de superficie, extracelulares y regulatorios propios de la bacteria que influyen en las propiedades de adhesión y la formación de biofilms. Por último, se intentará correlacionar la emisión de compuestos orgánicos volátiles por las bacterias rizosféricas con ciertos aspectos de la promoción del crecimiento de las plantas.

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This Study assessed the development of sludge treatment and reuse policy since the original 1993 National Sludge Strategy Report (Weston-FTA, 1993). A review of the 48 sludge treatment centres, current wastewater treatment systems and current or planned sludge treatment and reuse systems was carried out Sludges from all Regional Sludge Treatment Centres (areas) were characterised through analysis of selected parameters. There have been many changes to the original policy, as a result of boundary reviews, delays in developing sludge management plans, development in technology and changes in tendering policy, most notably a move to design-build-operate (DBO) projects. As a result, there are now 35 designated Hub Centres. Only 5 of the Hub Centres are producing Class A Biosolids. These are Ringsend, Killamey, Carlow, Navan and Osberstown. Ringsend is the only Hub Centre that is fully operational, treating sludge from surrounding regions by Thermal Drying. Killamey is producing Class A Biosolids using Autothermal Thermophilic Aerobic Digestion (ATAD) but is not, as yet, treating imported sludge. The remaining three plants are producing Class A Biosolids using Alkaline Stabilisation. Anaerobic Digestion with post pasteurisation is the most common form of sludge treatment, with 11 Hub Centres proposing to use it. One plant is using ATAD, two intend to use Alkaline Stabilisation, seven have selected Thermal Drying and three have selected Composting. While the remaining plants have not decided which sludge treatment to select, this is because of incomplete Sludge Management Plans and on DBO contracts. Analysis of sludges from the Hub Centres showed that all Irish sewage sludge is safe for agricultural reuse as defined by the Waste Management Regulations {Use of Sewage Sludge in Agriculture) (S.I. 267/2001), providing that a nutrient management plan is taken into consideration and that the soil limits of the 1998 (S.I. 148/1998) Waste Management Regulations are not exceeded.