Prevalence, behavioural and social factors associated with Schistosoma intercalatum and geohelminth infections in São Tomé and Principe

Copyright: Copyright 2008 Elsevier B.V., All rights reserved.A pilot study was conducted in schoolchildren from three main districts of São Tomé to assess the relationship between the prevalence of infections caused by Schistosoma intercalatum or intestinal helminths and individual behaviour and social conditions. Coprological examination revealed an increase of schistosome infections and a persisting high endemicity for ascariasis and trichuriasis. Infection rates were 36.2% for S. intercalatum and 70.8%, 68.5% and 4.6% for Ascaris lumbricoides, Trichuris trichiura and Ancylostomidae, respectively. Out of the 47 children positive for S. intercalatum, 35 (74.5%) were coinfected with one or more geohelminths. Logistic regression analysis of data collected through questionnaire demonstrate that behaviour and/or social conditions in the house were positively associated with S. intercalatum or T. trichiura. Neither sex nor age groups were associated with infections, suggesting that low personal hygiene and sanitation practices were similar for all groups of children. These data are in accordance to those of other studies and highlight the importance of assessing multivariate factors that may contribute to the transmission of these diseases, in order to design integrated control approaches for schistosomiasis and geohelminthiasis which could have more rapid effects on reduction of infections as well as greater cost-effectiveness.publishersversionpublishe

Differential tolerance of sugarcane cultivars to clomazone

Weed control is one of the most relevant costs of sugarcane production. If weeds are not controlled at the right time, the productivity and longevity of sugarcane plantations are reduced. In this crop, chemical control is the most used method, since it is efficient and it has a lower cost. Differentiated tolerance of sugarcane cultivars to the herbicide clomazone has been observed in the fields. However, there is no scientific evidence of this effect on the productivity of crops. This study evaluated the effects of clomazone on three sugarcane cultivars (RB966928, RB93579 and RB867515). Herbicide application was performed 40 days after the emergence of sugarcane plants and 7, 14, 21 and 28 days after the application, the toxicity caused by the herbicide in the culture was evaluated through grades ranging from 0 (no toxicity) to 100 (plant death). The harvest was performed 580 days after the herbicide application. On this occasion, the length and diameter of the stem, number of tillers, tons of stems per hectare, total soluble solids of the juice, sucrose of the juice, apparent purity of the juice, sugarcane fiber, reducing sugars and total recoverable sugars were evaluated. The differential tolerance among sugarcane cultivars in response to clomazone application in the early stages of crop development was confirmed. Nevertheless, in all cultivars, the symptoms of intoxication disappeared over time and did not reflect on crop productivity. It was concluded that plant control in the sugarcane crop with clomazone, following the recommendation of the manufacturer, does not interfere negatively in the growth, development and productivity of the crop.As plantas daninhas, se não controladas no momento adequado, reduzem a produtividade e longevidade dos canaviais. Nesta cultura, o método químico de controle das plantas daninhas, por ser eficiente e de menor custo, é o mais utilizado. No campo, tem-se observado tolerância diferenciada de cultivares de cana-de-açúcar ao herbicida clomazone. Contudo, não existe comprovação científica desse efeito sobre a produtividade dos cultivares. Neste trabalho foram avaliados os efeitos do clomazone em três cultivares de cana-de-açúcar (RB966928, RB93579 e RB867515). A aplicação do herbicida foi feita aos 40 dias após emergência das plantas de cana, e aos 7, 14, 21 e 28 dias após a aplicação foram avaliadas as intoxicações causadas pelo herbicida na cultura, atribuindo-se notas que variaram de 0 (ausência de intoxicação) até 100 (morte das plantas). Aos 580 dias após a aplicação foi realizada a colheita da cultura. Nessa ocasião, foram avaliados o comprimento e diâmetro do colmo, número de perfilho, tonelada de colmos por hectare, sólidos solúveis totais do caldo, sacarose do caldo, pureza aparente do caldo, fibra da cana, açúcares redutores e açúcares totais recuperáveis. Foi confirmada a tolerância diferenciada entre cultivares de cana-de-açúcar à aplicação do clomazone no início de desenvolvimento da cultura. Entretanto, os sintomas de intoxicação desapareceram ao longo do tempo e não refletiram na produtividade da cultura. Concluiu-se que o controle de plantas na cultura da cana-de-açúcar com o clomazone, seguindo a recomendação do fabricante, não interfere no crescimento, no desenvolvimento e na produtividade da cultura

On the independence of hydrogen production from methanogenic suppressor in olive mill wastewater

Anaerobic degradation of olive mill wastewater (OMW) at concentrations ranging from 2 to 100 g/L of chemical oxygen demand (COD) was assessed in batch assays. Methane was the main final product obtained for the lower concentrations tested. For 25 g COD/L, H2 was temporarily produced, albeit H2 depletion occurred, likely due to homoacetogenesis, since acetate was formed concomitantly. Hydrogen was produced and accumulated permanently in the assays containing 50 g COD/L of OMW. Methanogenesis and homoacetogenesis were naturally inhibited, suggesting that hydrogen recovery from OMW can be performed without the addition of methanogenic suppressors such as 2-bromoethanosulfonate. This fact opens new perspectives for the utilization of high OMW concentrations in a two-stage valorisation process combining biohydrogen and biomethane production.The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013, the FCT Project RECI/BBB-EBI/0179/2012, the Project "BioEnv - Biotechnology and Bioengineering for a sustainable world", REF. NORTE-07-0124-FEDER-000048, co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN, FEDER. Also through the project PTDC/ENR/69755/2006 and grants given to Marta Goncalves SFRH/BD/40746/2007, Jose Carlos Costa SFRH/BDP/48962/2008 and Angela A Abreu SFRH/BPD/82000/2011

Simple heuristics for the assembly line worker assignment and balancing problem

We propose simple heuristics for the assembly line worker assignment and balancing problem. This problem typically occurs in assembly lines in sheltered work centers for the disabled. Different from the classical simple assembly line balancing problem, the task execution times vary according to the assigned worker. We develop a constructive heuristic framework based on task and worker priority rules defining the order in which the tasks and workers should be assigned to the workstations. We present a number of such rules and compare their performance across three possible uses: as a stand-alone method, as an initial solution generator for meta-heuristics, and as a decoder for a hybrid genetic algorithm. Our results show that the heuristics are fast, they obtain good results as a stand-alone method and are efficient when used as a initial solution generator or as a solution decoder within more elaborate approaches.Comment: 18 pages, 1 figur

Influence of Quince rootstocks on Entomosporium Leaf Spot (Entomosporium mespili) susceptibility in European Pear cv. Abate Fetel

Entomosporium leaf spot (ELS) is caused by the fungus Fabraea maculata (anamorph: Entomosporium mespili) and affects most pear cultivars and quince rootstocks in Brazil. The aim of this study was to characterize the effect of Adams, EMA and EMC quince rootstocks on ELS in European pear cultivar “Abate Fetel” in Southern Brazil, during the 2009/2010, 2010/2011 and 2011/2012 growing season. The incidence and severity of disease was quantified weekly in 100 randomly leaves distributed in four medium-height branches per plant with eight replications. Disease progress curves of ELS were constructed and the epidemics compared according to: (1) the beginning of symptoms appearance (BSA); (2) the time to reach the maximum disease incidence and severity (TRMDI and TRMDS); (3) area under the incidence and severity disease progress curve (AUIDPC and AUSDPC). The data were analyzed by linear regression and adjusted for three empirical models: Logistic, Monomolecular and Gompertz. The Abate Fetel cultivar under all rootstocks evaluated was susceptible to E. mespili. However, there were significant differences in ELS intensity among rootstocks evaluated. The highest ELS intensities were observed in combinations with EMA and Adams quince rootstock. Abate Fetel cultivar grafted on EMC quince rootstock showed all epidemiological variables results significantly different when compared with EMA quince rootstock. EMC quince rootstock induced late resistance compared with the other considerated rootstocks. The Logistic model was the most appropriates to describe the ELS progress of Abate Fetel cultivar under all rootstocks evaluated in the edafoclimatic conditions of Southern Brazil, during the 2009/2010, 2010/2011 and 2011/2012 growing season

Leguminous cover crops improve the profitability and the sustainability of rainfed olive (Olea europaea L.) orchards: from soil biology to physiology of yield determination

The olive sector has a crucial economic, social, cultural and ecological relevance in the Mediterranean region, where tillage and herbicides application still are generalized practices. However, these techniques oppose to the recommendations of UE policy. Thus, other methods are needed to reduce adverse environmental impacts and to improve biodiversity, soil carbon sink and fertility, to save fossil fuels and to increase yield and the safety and nutritional value of food products. Meanwhile, since Mediterranean basin is particularly vulnerable to climate change, including lower precipitation in summer, olive tree will experiment some hard changes, mainly under rainfed conditions. Therefore, we propose an adequate management of cover crops to shift tillage and herbicides, in order to minimize runoff and evaporation water losses, conserve soil moisture storage and promote the infiltration of water in soil. The experiment was carried out during 4 years on a commercial orchard (cv. Cobrançosa) in Northeast Portugal. The treatments laid out were: (1) ordinary tillage techniques (OT) used by local growers (two tillage trips per year); (2) cover crop with self-reseeding annual legume species (AL); (3) natural vegetation fertilized (NVF) with 60 kg N hm2 (as in OT); (4) natural vegetation (NV) left unfertilized. The results revealed that AL treatment is the best option, reaching 37, 53 and 95% higher cumulative yield than NVF, OT and NV, respectively, in a closely association with greater physiological performance during the summer, mainly evidenced by lower oxidative damage and by favourable changes in water status and net photosynthetic rate, due to lower stomatal and mesophyll limitations. Moreover, the AL covered soil presented considerable microbial diversity and enzymatic activities, which may contribute to promote and conserve soil quality and health, as well the stability of ecosystems. Thus, leguminous cover crops improve the profitability and the sustainability of rainfed olive orchards.info:eu-repo/semantics/publishedVersio

Efeitos de diferentes níveis de N P K sobre o peso da matéria seca, na produção de mudas por via seminífera, do hedíquio amarelo, Hedychium gardnerianum sheppard ex ker-gawl, zingiberaceae

A study was made of the effect of different levels of N P K: N = 0,200, 400; P = 0,400, 800 and K = 0,200, 400 kg/ha, under field conditions, on the seedling production of ginger-lily, Hedyohium gardnerianum Sheppard ex Ker-gawl, Zingiberaceae and the influence on the dry matter Weight. From the data it was concluded that the best results were reached with the following levels: 20g of N; 80g of P; 20g of K/m² 40g of N; 80g of P; 40g of K/m² 20g of N; 40g of P; 40g of K/m².Estudou-se o efeito de aplicação de diferentes níveis de N P K: N = 0,200, 400; P = 0,400, 800 e K = 0,200, 400 kg/ha, em condições de campo na produção de mudas, por sementes, do hedíquio amarelo, Hedyohium gardnerianum Sheppard ex Ker-Gawl, Zingiberaceae, e sua influência sobre o peso da matéria seca. Através dos dados obtidos concluiu-se que a maior produção da matéria seca total, incluindo-se a parte aérea e o rizoma foram obtidos com os níveis de: a) 20g de N; 80 de P e 20 de K/m² b) 40g de N; 80 de P e 40 de K/m² c) 20g de N; 40 de P e 40 de K/m²

Efeito de espécies vegetais em bordadura em cebola sobre a densidade populacional de tripes e sirfídeos predadores.

Analisou-se a relação entre o efeito do plantio de diferentes espécies vegetais, em bordadura, na cultura da cebola, Allium cepa L, na incidência de Thrips tabaci Lind. e sirfídeos predadores, Toxomerus spp. O experimento foi conduzido na Epagri, EE de Ituporanga, de agosto a dezembro de 1998. Os tratamentos foram cebola em monocultivo; cebola + trigo mourisco (Fagopyrum esculentum Moench); cebola + nabo forrageiro (Raphanus sativus L. var. oleiferus Metzg.); cebola + cenoura (Daucus carota L., cv. Nantes e cv. Brasília); cebola + milho (Zea mays L.); cebola + rúcula (Eruca sativa L.) + vegetação espontânea. O plantio de diferentes espécies vegetais em bordadura não provocou diferenças significativas na incidência de tripes e sirfídeos predadores. A produtividade comercial de bulbos de cebola foi similar em sistema de monocultivo e diversificado, sugerindo ser possível adotar tais sistemas sem perdas em rendimento

Bulk viscosity driving the acceleration of the Universe

The possibility that the present acceleration of the universe is driven by a kind of viscous fluid is exploited. At background level this model is similar to the generalized Chaplygin gas model (GCGM). But, at perturbative level, the viscous fluid exhibits interesting properties. In particular the oscillations in the power spectrum that plagues the GCGM are not present. Possible fundamental descriptions for this viscous dark energy are discussed.Comment: Latex file, 8 pages, 3 eps figure

Semigroup Closures of Finite Rank Symmetric Inverse Semigroups

We introduce the notion of semigroup with a tight ideal series and investigate their closures in semitopological semigroups, particularly inverse semigroups with continuous inversion. As a corollary we show that the symmetric inverse semigroup of finite transformations $\mathscr{I}_\lambda^n$ of the rank $\leqslant n$ is algebraically closed in the class of (semi)topological inverse semigroups with continuous inversion. We also derive related results about the nonexistence of (partial) compactifications of classes of semigroups that we consider.Comment: With the participation of the new coauthor - Jimmie Lawson - the manuscript has been substantially revised and expanded. Accordingly, we have also changed the manuscript titl