6,148 research outputs found

    Attractiveness of host plant volatile extracts to the Asian citrus psyllid, diaphorina citri, is reduced by terpenoids from the non-host cashew

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    Diaphorina citri is a vector of the bacterial causative agent of Huanglongbing (HLB = Citrus greening), a severe disease affecting citrus crops. As there is no known control for HLB, manipulating insect behaviour through deployment of semiochemicals offers a promising opportunity for protecting citrus crops. The behavioural responses of D. citri to plant volatiles, and the identity of these plant volatiles were investigated. Volatiles were collected from host plants Murraya paniculata, Citrus sinensis, C. reshni, C. limettioides, Poncirus trifoliata, and from non-host plants Psidium guajava, Mangifera indica, Anacardium occidentale. In behavioural assays, female D. citri spent more time in the arms containing volatiles from either M. paniculata or C. sinensis compared to the control arms. When D. citri was exposed to volatiles collected from A. occidentale, they preferred the control arm. Volatiles emitted from the other studied plants did not influence the foraging behaviour of D. citri. Chemical analyses of volatile extracts from C. sinensis, M. paniculata, and A. occidentale revealed the presence of the terpenoids (E)-4,8-dimethylnona-1,3,7–triene (DMNT) and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT) in higher amounts in A. occidentale. In further behavioural bioassays, female D. citri spent less time in arms containing a synthetic blend of DMNT and TMTT compared to the control arms. Female D. citri also spent less time in arms containing the synthetic blend in combination with volatile extracts from either M. paniculata or C. sinensis compared to the control arms. Results suggest that higher release of the two terpenoids by A. occidentale make this species unattractive to D. citri, and that the terpenoids could be used in reducing colonisation of citrus plants and therefore HLB infection

    Assessment of the effectiveness of steel fibre reinforcement for the punching resistance of flat slabs by experimental research and design approach

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    The present paper deals with the experimental assessment of the effectiveness of steel fibre reinforcement in terms of punching resistance of centrically loaded flat slabs, and to the development of an analytical model capable of predicting the punching behaviour of this type of structures. For this purpose, eight slabs of 2550 x 2550 x 150 mm3 dimensions were tested up to failure, by investigating the influence of the content of steel fibres (0, 60, 75 and 90 kg/m3) and concrete strength class (50 and 70 MPa). Two reference slabs without fibre reinforcement, one for each concrete strength class, and one slab for each fibre content and each strength class compose the experimental program. All slabs were flexurally reinforced with a grid of ribbed steel bars in a percentage to assure punching failure mode for the reference slabs. Hooked ends steel fibres provided the unique shear reinforcement. The results have revealed that steel fibres are very effective in converting brittle punching failure into ductile flexural failure, by increasing both the ultimate load and deflection, as long as adequate fibre reinforcement is assured. An analytical model was developed based on the most recent concepts proposed by the fib Mode Code 2010 for predicting the punching resistance of flat slabs and for the characterization of the behaviour of fibre reinforced concrete. The most refined version of this model was capable of predicting the punching resistance of the tested slabs with excellent accuracy and coefficient of variation of about 5%.The study presented in this paper is a part of the research project titled "SlabSys-HFRC - Flat slabs for multi-storey buildings using hybrid reinforced self-compacting concrete: an innovative structural system", with reference number of PTDC/ECM/120394/2010. The second author acknowledges the support provided by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) grant, and the grant provided by the project SlabSys. The authors would acknowledge the collaboration of Casais Company on the preparation of the moulds and flexural reinforcement, CiviTest on the design of the SFRSCC for the slabs, and Maccaferri, Secil (Unibetao), and Sika companies for the supplying of steel fibres, concrete and superplasticizers, respectively

    Chromatographic Methods Applied to the Characterization of Bio-Oil from the Pyrolysis of Agro-Industrial Biomasses

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    Biomass conversion into solid, liquid and gaseous products by pyrolytic technology is one of the most promising alternative to convert the biomass into useful products and energy. The total characterization of the products from the pyrolysis of biomass is one of the great challenges in this field, mainly due to their molecular complexity. Pyrolysis is a process that causes degradation of biomass in a non‐oxidative atmosphere, at relatively high temperatures, producing a solid residue rich in carbon and mineral matter, gases and bio‐oil. The yield and properties of the products depend on the nature of the biomass and the type of the pyrolysis process (type of reactor, temperature, gas flow, catalyst). Due to the high molecular complexity of bio‐oil, many different technical had been developed to their complete characterization. This chapter describes the principles of the techniques and main application of chromatographic methods (GC, LC, GC × GC, LC × LC, Nano‐LC) in the analysis of bio‐oils derived from thermo‐degradation of biomasses. Especial attention is carried out to two‐dimensional techniques that represent the state of the art in terms of separation, sensibility, selectivity and velocity of data acquisition for characterization of complex organic mixtures. For proper use of bio‐oil in the chemical industry, it is essential the identification and unambiguous determination of its major constituents. Only then, it is possible to propose a recovery route of some of these components for the development of an industry dedicated to a bio‐refinery. For this, chromatographic methods, especially GC × GC/MS, are fundamental because they allow analysis with high sensitivity and accuracy in identifying each constituent of the bio‐oil

    Avaliação de programa para reduzir dores nas costas em trabalhadores de enfermagem

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    OBJECTIVE: To evaluate the effectiveness of a program designed to reduce back pain in nursing aides. METHODS: Female nursing aides from a university hospital who had suffered episodes of back pain for at least six months were included in the study. Participants were randomly divided into a control group and an intervention group. The intervention program involved a set of exercises and an educational component stressing the ergonomic aspect, administered twice a week during working hours for four months. All subjects answered a structured questionnaire and the intensity of pain was assessed before and after the program using a visual analogue scale (VAS). Student's t-test or the Wilcoxon Rank Sum Test for independent samples, and Chi-square test or the Exact Fisher test for categorical analysis, were used. The McNemar test and the Wilcoxon matched pairs test were used to compare the periods before and after the program. RESULTS: There was a statistically significant decrease in the frequency of cervical pain in the last two months and in the last seven days in the intervention group. There was also a reduction in cervical pain intensity in the two periods (2 months, 7 days) and lumbar pain intensity in the last 7 days. CONCLUSIONS: The results suggest that a program of regular exercise with an emphasis on ergonomics can reduce musculoskeletal symptoms in nursing personnel.OBJETIVO: Avaliar o efeito de um programa na redução de dores nas costas em auxiliares de enfermagem. MÉTODOS: Participaram do estudo auxiliares de enfermagem com menos de 50 anos de idade, do sexo feminino, de um hospital universitário e que apresentavam dores nas costas por um período mínimo de 6 meses. O programa envolveu parte educativa, com abordagem ergonômica, e a realização de exercícios executados durante o horário de trabalho, duas vezes por semana, em um período de quatro meses. As participantes foram divididas aleatoriamente em grupo tratado e grupo controle. A intensidade das dores foi avaliada pela escala visual analógica. Foram utilizados os testes t de Student ou de Wilcoxon, para amostras independentes e os testes Qui-quadrado ou Exato de Fisher, para as categóricas. Para comparar as proporções do início e final do programa utilizou-se o teste de McNemar. RESULTADOS: Ocorreu diminuição estatisticamente significativa na freqüência de dor cervical durante os últimos dois meses e durante a ultima semana no grupo tratado. Houve também redução na intensidade da dor cervical em ambos os períodos (2 meses; 7 dias) e da dor lombar na última semana. CONCLUSÕES: O estudo sugere que programa regular de exercícios, acompanhado por abordagem instrucional ergonômica, pode reduzir sintomas músculo-esqueléticos em trabalhadores de enfermagem.35636

    Influence of two acyclic homoterpenes (Tetranorterpenes) on the foraging behavior of anthonomus grandis Boh

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    Previous studies have shown that the boll weevil, Anthonomus grandis, is attracted to constitutive and conspecific herbivore-induced cotton volatiles, preferring the blend emitted by cotton at the reproductive over the vegetative stage. Moreover, this preference was paralleled by the release of the acyclic homoterpenes (tetranorterpenes) (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT) in Delta Opal cotton being higher at the vegetative than at the reproductive stage. Here, we evaluated whether this difference in release of acyclic homoterpenes also occurred in other cotton varieties, and if boll weevils could recognize these compounds as indicators of a specific cotton phenological stage. Results showed that cotton genotypes CNPA TB-90, BRS-293 and Delta Opal all produced higher levels of DMNT and TMTT at the vegetative stage than at the reproductive stage and that these homoterpenes allowed for principal component analysis separation of volatiles produced by the two phenological stages. Electroantennograms confirmed boll weevil antennal responses to DMNT and TMTT. Behavioral assays, using Y-tube olfactometers, showed that adding synthetic homoterpenes to reproductive cotton volatiles (mimicking cotton at the vegetative stage in terms of homoterpene levels) resulted in reduced attraction to boll weevils compared to that to unmodified reproductive cotton. Weevils showed no preference when given a choice between plants at the vegetative stage and the vegetative stage-mimicked plant. Altogether, the results show that DMNT and TMTT are used by boll weevils to distinguish between cotton phenological stages

    Cardiac Troponin T and Illness Severity in the Very-Low-Birth-Weight Infant

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    Introduction. Respiratory distress are very common in Very-low-birth-weight (VLBW) infants and Myocardial injury may play a role in the disease outcome. Cardiac troponin T (cTnT) is the most useful marker of injury in adult population, but has not been extensively studied in this population. Aim. To study the role of cTnT in VLBW infants and its association with clinical outcomes. Methods. All VLBW infants admitted to our NICU were included in the study. Echocardiography and blood samples for cTnT determination were collected at 24 and 48 hours of life, and values >0.1 ng/mL were considered CTnT-positive values. Results. A total of 116 neonates had their blood samples collected. The median cTnT concentration within 24 hours was 0.191 (0.1–0.79) ng/mL and within 48 hours was 0.293 (0.1–1.0) ng/mL. A logistic regression analysis showed that PDA, low GA, and use of dopamine were independently associated with positive cTnT and abnormal Dopplerfluxometry and diuretics use had protective effects and was independently associated with troponin values. Conclusion. We observed a high prevalence of positivecTnT values in VLBW infants associated with illness severity. Our findings suggest that cTnT may be a useful and early marker of myocardial injury in VLBW infants

    MIGRANTES TEMPORALES: RESIGNIFICACIÓN DE LAS NARRATIVAS

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     El objetivo de este texto es el análisis de las narrativas de campesinos migrantes temporales, procedentes de dos regiones de fuerte emigración en Brasil: el estado de Paraíba, (situado en el nordeste del país), y el norte de Minas Gerais (situado en la región sudeste), donde se localiza el Vale do Rio Jequitinhonha. El estado de São Paulo es el principal destino de estos campesinos migrantes a causa de los extensos cañaverales que, actualmente, cubren un área de más de cinco millones de hectáreas. Son utilizadas también las narrativas de campesinos migrantes para la ciudad de São Paulo y de Rio de Janeiro. La metodología se basa en la Historia Oral. El eje principal de las reflexiones sostiene la idea de que no hay una desaparición de las narrativas causada por las constantes migraciones, sino una resignificación de las mismas, a partir de la experiencia migratoria. Palabras clave: Trabajo, emigración, narrativas.   Abstract The aim of this article is to analyse the narratives of  the temporary peasant migrants  from two important emigration regions in Brazil:  the State of Paraiba (located in the Northeast region) and  Vale of Jequitinhonha River in the North of Minas Gerais (located in the southeast region). The  main destination of the peasant migrants  is the sugar cane fields in the State of São Paulo, which covers over five millions of hectares of land. The narratives of peasant  migrants who go to the cities of São Paulo and Rio de Janeiro are also analysed in the article. The methodology is grounded on oral history. The main idea of the analysis  is that the narrative has not disappeared due to the permanent migrations, but there has been a re-interpretation of the narratives throughout the migration experience. Keywords: Job, emigration, narratives

    PESQUISA E EXTENSÃO NA MODALIDADE DE ENSINO A DISTÂNCIA: A EXPERIÊNCIA DA LICENCIATURA EM TURISMO

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    O ensino a distância surge, no Brasil, como um projeto de ampliação de acesso ao nível superior, porém a garantia do tripé “ensino, pesquisa e extensão” ainda é um desafio para essa modalidade. O ensino a distância é mediatizado pela plataforma do ambiente virtual de aprendizagem (AVA) e por intermédio de tutores, materiais didáticos, polos e de ligações através de números 0800.Além de suscitar uma série de interessantes e relevantes debates acerca de formas de construção do conhecimento, pensar pesquisa e extensão em uma nova modalidade de ensino é rever as concepções filosóficas que permeiam o ensino como um todo. Através da contextualização do ensino a distância no Estado do Rio de Janeiro e do Curso de Licenciatura em Turismo,pretende-se refletir sobre o papel da pesquisa e extensão nesta modalidade, utilizando para tal a experiência em andamento dois projetos de pesquisa e extensão que estão sendo desenvolvidos

    Cell therapy in diabetes mellitus

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    Nesta revisão são discutidas várias alternativas de regeneração do conjunto de células produtoras de insulina do pâncreas, usando células-tronco embrionárias do cordão umbilical e adultas, e o trabalho que está sendo realizado em nosso grupo de pesquisas utilizando imunossupressão em altas doses combinada com a infusão de células-tronco hematopoéticas autólogas em diabete do tipo 1 recém-diagnosticado.In this review, we discuss several alternatives for the regeneration of the pool of insulin-producing cells by the pancreas using embryonic, cord blood or adult stem cells and the work being carried out by our research group using high dose immunosuppression with autologous hematopoietic stem cells in newly diagnosed type 1 diabetes mellitus
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