1,189 research outputs found

    Occurrence of Entomophthorales on Spittlebugs Pests of Pasture in Eastern São Paulo State, Brazil

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    Spittlebugs (Hemiptera: Cercopidae) are the most important pests of pasture in Brazil. Nymphal behavior, i.e. residing in the soil, makes their control with insecticides difficult. Although Entomophthorales fungi occasionally have been found at epizootic levels in spittlebug populations, they have not been cultured, had their incidence levels determined, nor evaluated for pest control potential. The research reported here aimed to evaluate the occurrence of Entomophthorales species on spittlebug pests of pasture in Pindamonhangaba County, São Paulo State, Brazil. Evaluations were carried out in 2 adjacent fields with Brachiaria decumbens and Pennisetum purpureum grasses, respectively, of 5 ha each. Evaluations were done every 4 days from January through February by capturing spittlebug adults on leaves with an entomological sweep net, and the insect samples were kept frozen until examined. Insect abdomens were dissected and observed by microscopy for the presence of hyphae and resting spores. Insects cadavers with sporulating fungus were collected in the field and taken immediately to the lab to isolate the pathogen. Scanning electron microscopy pictures were taken of conidophores, and primary and secondary conidia of both fungi. Furia sp. was found at epizootic levels on Deois schach in the Brachiaria pasture, reaching 80% infected followed by a fall in the insect population. Batkoa sp. was found at enzootic levels (\u3c 10% infected) on Mahanarva fimbriolata in the P. purpureum pasture. Furia sp. also was found to infect another important spittlebug, Deois flavopicta, indicating that it has good potential as a bioinsecticide. Heavy rainfall adversely affected the occurrence of Batkoa sp. in M. fimbriolata populations in P. purpureum pasture

    Quantum cosmology of scalar-tensor theories and self-adjointness

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    In this paper, the problem of the self-adjointness for the case of a quantum minisuperspace Hamiltonian retrieved from a Brans-Dicke (BD) action is investigated. Our matter content is presented in terms of a perfect fluid, onto which the Schutz's formalism will be applied. We use the von Neumann theorem and the similarity with the Laplacian operator in one of the variables to determine the cases where the Hamiltonian is self-adjoint and if it admits self-adjoint extensions. For the latter, we study which extension is physically more suitable.Comment: Latex file, 12 pages. Small changes made in the paper, and a a new appendix adde

    Motivos para la práctica de correr y su influencia en la satisfacción con la vida

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    O objetivo do presente estudo foi analisar a influência dos motivos para prática da corrida de rua na satisfação com a vida de corredores amadores. O estudo se caracteriza como de abordagem quantitativa. O procedimento de coleta adotado foi o E-survey, onde os indivíduos foram convidados através das redes sociais a responder um formulário online disponível na plataforma Google Drive. A amostra foi composta por 158 corredores. O instrumento utilizado foi um questionário composto pelas variáveis: (i) motivos; (ii) satisfação com a vida; (iii) perfil da prática da corrida de rua e (iv) caracterização dos dados demográficos. Os dados foram analisados no software SPSS Statistics 24. A análise do valor preditivo das variáveis independes resultou num modelo estatisticamente significativo [F (3, 154) = 13,06; < 0,001; R² = 0,20]. Especificamente, o fator social exerceu a influência mais forte (β = 0.325), seguida pelo divertimento (β = 0.198). Portanto, conclui-se que os motivos da prática da corrida de rua são fatores significativos para a satisfação com a vida.The aim of this study was to analyze the influence of motivations for running practice on the life satisfaction of amateur runners. The study is characterized as a quantitative research. The data collection procedure adopted was the E-survey, where individuals were invited through social networks to answer an online survey form available on the Google Drive platform. The sample consisted of 158 runners. The instrument used was a questionnaire composed of: (i) motivations; (ii) life satisfaction; (iii) running profile (iv) characterization of demographic data. The data were analyzed using the SPSS Statistics 24 software. The analysis of the predictive value of the independent variables resulted in a statistically significant model [F (3, 154) = 13.06; <0.001; R² = 0.20]. Specifically, the social factor exerted the strongest influence (β = 0.325), followed by entertainment (β = 0.198). As a conclusion, the motivations for running practice prove to be significant factors for life satisfaction.El objetivo del presente estudio fue analizar la influencia de los motivos de la práctica de correr en la satisfacción con la vida de los corredores aficionados. El estudio se caracteriza por ser un enfoque cuantitativo. El procedimiento de recolección adoptado fue la encuesta electrónica, donde se invitó a las personas a través de las redes sociales a contestar un formulario en línea disponible en la plataforma Google Drive. La muestra estuvo conformada por 158 corredores. El instrumento utilizado fue un cuestionario compuesto por las variables: (i) motivos; (ii) satisfacción con la vida; (iii) perfil de práctica de carrera y (iv) caracterización de datos demográficos. Los datos se analizaron utilizando el software SPSS Statistics 24. El análisis del valor predictivo de las variables independientes resultó en un modelo estadísticamente significativo [F (3, 154) = 13,06; <0,001; R² = 0,20]. En concreto, el factor social ejerció la mayor influencia (β = 0,325), seguido del entretenimiento (β = 0,198). Por lo tanto, se concluye que los motivos de la práctica de correr en la calle son factores importantes para la satisfacción con la vida.Facultad de Humanidades y Ciencias de la Educació

    Quantum Particle Production at Sudden Singularities

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    We investigate the effects of quantum particle production on a classical sudden singularity occurring at fine time in a Friedmann universe. We use an exact solution to describe an initially radiation-dominated universe that evolves into a sudden singularity at finite time. We calculate the density of created particles exactly and find that it is generally much smaller than the classical background density and pressure which produce the sudden singularity. We conclude that, in the example studied, the quantum particle production does not lead to the avoidance or modification to the sudden future singularity. We argue that the effects of small residual anisotropies in the expansion will not change these results and show how they can be related to studies of classical particle production using a bulk viscosity. We conclude that we do not expect to see significant observable effects from local sudden singularities on our past light cone.Comment: Latex file, 13 pages, five figures in eps format. Extended discussion, new appendix and added reference

    Randomized controlled trial of probiotics for the prevention of spontaneous preterm delivery associated with intrauterine infection: study protocol

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    Background: Spontaneous preterm deliveries that occur before the 34th week of gestation, and particularly before the 32nd week of gestation, have been strongly associated to intrauterine infection, ascending from vagina, and represent the largest portion of neonatal deaths and neurological problems. Bacterial vaginosis, characterized by a diminished or absent flora of lactobacilli and increased colonization of several anaerobic or facultative microorganisms, increases two times the risk of preterm delivery before the 34th week. Trials of antibiotics failed to show efficacy and effectiveness against spontaneous preterm birth related to bacterial vaginosis. Some studies indicate benefit from selected probiotics to treat genitourinary infections, including bacterial vaginosis. Objective: The purpose of this study is to evaluate the effectiveness of the early administration of selected probiotics to pregnant women with asymptomatic bacterial vaginosis/intermediate degree infection to reduce the occurrence of spontaneous preterm delivery and related neonatal mortality and morbidity. Methods/Design: Women attending public prenatal care services in Rio de Janeiro will be screened to select asymptomatic pregnant women, less than 20 weeks' gestation, with no indication of elective preterm delivery. Those with vaginal pH > = 4.5 and a Nugent score between 4 and 10 (intermediate degree infection or bacterial vaginosis) will be randomized to either the placebo or the intervention group, after written informed consent. Intervention consists in the use of probiotics, Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14, 2 capsules a day, each capsule containing more than one million bacilli of each strain, for 6-12 weeks, up to the 24th-25th wk of gestation. Ancillary analyses include quantification of selected cervicovaginal cytokines and genotyping of selected polymorphisms. The randomization process is stratified for history of preterm delivery and blocked. Allocation concealment was designed as well as blinding of women, caregivers and outcome evaluators. The study will be supervised by an independent monitoring committee. Outcomes under study are preterm delivery (< 34- < 32 weeks of gestation) and associated neonatal complications: early neonatal sepsis, bronchopulmonary dysplasia, periventricular leukomalacia, necrotizing enterocolitis, and prematurity-related retinopathy; definitions were adapted from those recommended by the 2002 version of the Vermont-Oxford Network. Trial registration at NIH register: NCT00303082

    Isolation and functional characterization of a cotton ubiquitination-related promoter and 5'UTR that drives high levels of expression in root and flower tissues

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    <p>Abstract</p> <p>Background</p> <p>Cotton (<it>Gossypium </it>spp.) is an important crop worldwide that provides raw material to 40% of the textile fiber industry. Important traits have been studied aiming the development of genetically modified crops including resistance to insect and diseases, and tolerance to drought, cold and herbicide. Therefore, the characterization of promoters and regulatory regions is also important to achieve high gene expression and/or a specific expression pattern. Commonly, genes involved in ubiquitination pathways are highly and differentially expressed. In this study, we analyzed the expression of a cotton ubiquitin-conjugating enzyme (E2) family member with no previous characterization.</p> <p>Results</p> <p>Nucleotide analysis revealed high identity with cotton <it>E2 </it>homologues. Multiple alignment showed a premature stop codon, which prevents the encoding of the conserved cysteine residue at the <it>E2 </it>active site, and an intron that is spliced in <it>E2 </it>homologues, but not in <it>GhGDRP85</it>. The <it>GhGDRP85 </it>gene is highly expressed in different organs of cotton plants, and has high transcript levels in roots. Its promoter (uceApro2) and the 5'UTR compose a regulatory region named uceA1.7, and were isolated from cotton and studied in <it>Arabidopsis thaliana</it>. uceA1.7 shows strong expression levels, equaling or surpassing the expression levels of CaMV35S. The uceA1.7 regulatory sequence drives GUS expression 7-fold higher in flowers, 2-fold in roots and at similar levels in leaves and stems. GUS expression levels are decreased 7- to 15-fold when its 5'UTR is absent in uceApro2.</p> <p>Conclusions</p> <p>uceA1.7 is a strong constitutive regulatory sequence composed of a promoter (uceApro2) and its 5'UTR that will be useful in genetic transformation of dicots, having high potential to drive high levels of transgene expression in crops, particularly for traits desirable in flower and root tissues.</p

    Mitochondrial echoes of first settlement and genetic continuity in El Salvador

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    Background: From Paleo-Indian times to recent historical episodes, the Mesoamerican isthmus played an important role in the distribution and patterns of variability all around the double American continent. However, the amount of genetic information currently available on Central American continental populations is very scarce. In order to shed light on the role of Mesoamerica in the peopling of the New World, the present study focuses on the analysis of the mtDNA variation in a population sample from El Salvador. Methodology/Principal Findings: We have carried out DNA sequencing of the entire control region of the mitochondrial DNA (mtDNA) genome in 90 individuals from El Salvador. We have also compiled more than 3,985 control region profiles from the public domain and the literature in order to carry out inter-population comparisons. The results reveal a predominant Native American component in this region: by far, the most prevalent mtDNA haplogroup in this country (at ~90%) is A2, in contrast with other North, Meso- and South American populations. Haplogroup A2 shows a star-like phylogeny and is very diverse with a substantial proportion of mtDNAs (45%; sequence range 16090–16365) still unobserved in other American populations. Two different Bayesian approaches used to estimate admixture proportions in El Salvador shows that the majority of the mtDNAs observed come from North America. A preliminary founder analysis indicates that the settlement of El Salvador occurred about 13,400±5,200 Y.B.P.. The founder age of A2 in El Salvador is close to the overall age of A2 in America, which suggests that the colonization of this region occurred within a few thousand years of the initial expansion into the Americas. Conclusions/Significance: As a whole, the results are compatible with the hypothesis that today's A2 variability in El Salvador represents to a large extent the indigenous component of the region. Concordant with this hypothesis is also the observation of a very limited contribution from European and African women (~5%). This implies that the Atlantic slave trade had a very small demographic impact in El Salvador in contrast to its transformation of the gene pool in neighbouring populations from the Caribbean facade

    Microsatellite analysis supports clonal propagation and reduced divergence of Trypanosoma vivax from asymptomatic to fatally infected livestock in South America compared to West Africa

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    Background: Mechanical transmission of the major livestock pathogen Trypanosoma vivax by other biting flies than\ud tsetse allows its spread from Africa to the New World. Genetic studies are restricted to a small number of isolates\ud and based on molecular markers that evolve too slowly to resolve the relationships between American and West\ud African populations and, thus, unable us to uncover the recent history of T. vivax in the New World.\ud Methods: T. vivax genetic diversity, population structure and the source of outbreaks was investigated through the\ud microsatellite multiloci (7 loci) genotype (MLGs) analysis in South America (47isolates from Brazil, Venezuela and\ud French Guiana) and West Africa (12 isolates from The Gambia, Burkina Faso, Ghana, Benin and Nigeria).\ud Relationships among MLGs were explored using phylogenetic, principal component and STRUCTURE analyses.\ud Results: Although closely phylogenetically related, for the first time, genetic differences were detected between\ud T. vivax isolates from South America (11 genotypes/47 isolates) and West Africa (12 genotypes/12 isolates) with no\ud MLGs in common. Diversity was far greater across West Africa than in South America, where genotypes from Brazil\ud (MLG1-6), Venezuela (MLG7-10) and French Guiana (MLG11) shared similar but not identical allele composition. No\ud MLG was exclusive to asymptomatic (endemic areas) or sick (outbreaks in non-endemic areas) animals, but only\ud MLGs1, 2 and 3 were responsible for severe haematological and neurological disorders.\ud Conclusions: Our results revealed closely related genotypes of T. vivax in Brazil and Venezuela, regardless of\ud endemicity and clinical conditions of the infected livestock. The MLGs analysis from T. vivax across SA and WA\ud support clonal propagation, and is consistent with the hypothesis that the SA populations examined here derived\ud from common ancestors recently introduced from West Africa. The molecular markers defined here are valuable to\ud assess the genetic diversity, to track the source and dispersion of outbreaks, and to explore the epidemiological\ud and pathological significance of T. vivax genotypes.This work was funded through projects within the PROAFRICA and PROSUL programs from the Brazilian agency CNPq. We are grateful to Professor Erney P. Camargo for the joint coordination of these projects and helpful commentaries on the manuscript. HAG was funded by a CDCH-UCV studentship from Venezuela; ACR is a postdoctoral fellow of PNPD-CAPES and CMFR is recipient of PhD scholarships from CNPq-PROTAX. The authors would like to acknowledge for clinical and epidemiological information, blood samples of T. vivax infected livestock and valuable help in the fieldwork several colleagues Garcia et al. Parasites & Vectors 2014, 7:210 Page 11 of 13\ud http://www.parasitesandvectors.com/content/7/1/210 from African countries, Venezuela and Brazil (Galiza GF, Da Silva A and Cadioli L\ud also for previous joint studies). We are grateful to The Wellcome Trust for making available sequences from the genome of T. vivax from Sanger Institute. We are deeply in debt to Wendy Gibson (Bristol University, UK) for helpful discussions and suggestions that much improved our manuscript

    Soil cover plants on water erosion control in the South of Minas Gerais

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    Water erosion is responsible for soil, water, carbon and nutrient losses, turning into the most important type of degradation of Brazilian soils. This study aimed to evaluate the influence of three cover plants under two tillage systems on water erosion control in an Argisol at south of Minas Gerais state, Brazil. The cover plants utilized in the study were pigeon pea, jack bean and millet, under contour seeding and downslope tillage. Experimental plots of 4 x 12 m, with 9% slope, under natural rainfall were used for the quantification of losses of soil, water, nutrients, and organic matter. One experimental plot was kept without plant cover (reference). Higher erosivity was observed in December and January, although a great quantity of erosive rainfall was detected during the whole raining period. Contour seeding provided a greater reduction of water erosion than downslope tillage, as expected. The jack bean under contour seeding revealed the lowest values of soil, water, nutrients and organic matter losses
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