250 research outputs found

    An Empirical Evaluation of the Cost and Effectiveness of Structural Testing Criteria for Concurrent Programs

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    AbstractConcurrent program testing is not a trivial task. Features like nondeterminism, communication and synchronization impose new challenges that must be considered during the testing activity. Some initiatives have proposed testing approaches for concurrent programs, in which different paradigms and programming languages are considered. However, in general, these contributions do not present a well-formed experimental study to validate their ideas. The problem is that the data used and generated during the validation is not always available, hampering the replication of studies in the context of other testing approaches. This paper presents an experimental study, taking into account the concepts of the Experimental Software En- gineering to evaluate the cost, effectiveness and strength of the structural testing criteria for message-passing programs. The evaluation was conducted considering a benchmark composed of eight MPI programs. A set of eight structural testing criteria defined for message-passing programs was evaluated with the ValiMPI testing tool, which provides the support required to apply the investigated testing criteria. The results indicate the complementary aspect of the criteria and the information about cost and effectiveness has contributed to the establishment of an incremental testing strategy to apply the criteria. All material generated during the experimental study is available for further comparisons

    Water buffalo production in the Brazilian Amazon Basin: a review

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    The Brazilian Amazon has witnessed, in the last decades, an increase in the water buffalo (Bubalus bubalis) inventory, with interesting productivity results. As the Brazilian Amazon contains the main water buffalo population in the Americas, the aim of this work is to review its most relevant production systems and some peculiarities about meat and milk production in this territory. The opening section describes the Amazon Basin, the most common water buffalo breeds, a brief history of the local livestock farming beginning in 1644. Also, it presents how water buffaloes gradually replaced bovine herds, especially where the latter had a lower productive performance. The use of extensive or more intensified models is pointed out and the ecosystems in which buffaloes are raised are detailed since native or cultivated pastures can be used in floodplains or drylands. Buffalo raising is favored in the Amazon due to the climate, soil, genetic variability of forages, animal adaptability, and physical space. Thus, it is clear that buffaloes have a high potential for meat and milk production and are an alternative in the use of altered areas of the Amazon; and, in the recent past, the low profitability of buffalo farming in traditional production systems in the Amazon was the reason which made this activity economically unattractive. Most recent technologies as outdoor confinements and silvopastoral systems are pointed out as more suitable regarding land-use policies, and buffalo farming for meat and milk production fits perfectly in this context, with productivity and beneficial socioeconomicinfo:eu-repo/semantics/acceptedVersio

    Effects of deliberate reflection on students' engagement in learning and learning outcomes

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    Context Reflection in practice is assumed to enhance interest in knowing more about a topic, increasing engagement in learning and learning outcomes. However, this claim lacks empirical evidence, particularly in medical education. The authors investigated the effects of deliberate reflection upon clinical cases on medical students’ engagement in a learning activity and learning outcomes. Methods A three‐task (diagnostic task; learning activity; test) experiment was conducted in August 2017. Seventy‐two fourth‐year students from UNIFENAS‐BH Medical School, Brazil, diagnosed two clinical cases with jaundice as the chief complaint, either by following a deliberate reflection procedure or making differential diagnosis. Subsequently, all participants received the same study material on the diagnosis of jaundice. Finally, they took a recall test on the study material. Outcome measurements were study time and test scores. Results There was a significant effect of experimental condition on students’ engagement in the learning activity and on learning outcomes. Students who deliberately reflected upon the cases invested more time in studying the material than those who made a differential diagnosis (respectively, mean = 254.97, standard deviation = 115.45 versus mean = 194.96, standard deviation = 111.68; p = 0.02; d = 0.53). Deliberate reflection was also related to higher scores in the test relative to differential diagnosis (respectively, mean = 22.08, standard deviation = 14.94 versus mean = 15.75, standard deviation = 9.24; p = 0.03; d = 0.51). Medium effect sizes (Cohen's d) were observed in both measurements. Conclusions Relative to making differential diagnosis, deliberate reflection while diagnosing cases fostered medical students’ engagement in learning and increased learning outcomes. Teachers can employ this relatively easy procedure, possibly both with simulated and real scenarios, to motivate their students and help them expand their knowledge, an important requirement for their professional development

    Digestible lysine effects on gene expression by Japanese quails in the pre-laying phase

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    This study aimed to determine the effects of digestible lysine levels in the diets of Japanese quail (Coturnix coturnix japonica) on performance, blood parameters and the expression of insulin-like growth factor I, and growth hormone receptor (GHR), apolipoprotein A-I (APOA-I), acetyl-CoA-carboxylase (ACC), and fatty acid synthase (FAS) genes. A total of 288 seven-day-old female Japanese quails were randomly assigned to one of three diets that contained 0.8%, 1.10%, or 1.40% digestible lysine. The birds were slaughtered at 42 days old, and relative gene expression was evaluated in the liver by qRT-PCR using the 2-ΔCT method. Lysine supplementation had no effect on weight gain and feed conversion. Abdominal fat was lower in birds supplemented with 0.8% digestible lysine than those supplemented with 1.10% and 1.40%. Increased total cholesterol and triglycerides were elevated in quails that received supplementation of 1.10% digestible lysine compared with the other diets. High density lipoproteins were decreased in birds that received 0.8% digestible lysine. Quails fed with 1.40% digestible lysine had greater expression of GHR and APOA-I than quails fed diets with 0.8 and 1.10% (P <0.05). The greatest expressions of ACC and FAS were observed in the liver of quails fed with 0.8% digestible lysine. The current results suggest that lysine supplementation in the pre-laying phase allows birds to deposit muscle mass to reach the optimal conformation and body fatness that provides an energetic reserve for the productive phase by modulating the expression of genes related to growth and lipid metabolism. Keywords: Coturnix coturnix japonica, growth, growth hormone, lipid synthesis, lipid metabolis

    The role of lubricant feeding conditions on the performance improvement and friction reduction of journal bearings

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    Most conventional hydrodynamic journal bearing performance tools can not suitably assess the effect of lubricant feeding conditions on bearing performance, even though these conditions are known to affect important performance parameters such as eccentricity and powerloss. A thermohydrodynamic analysis suitable to deal with realistic feeding conditions has been proposed. Special attention was given to the treatment of phenomena taking place within grooves and their vicinity,as well as to the ruptured film region. The effec to flubricant feeding pressure and temperature, groove length ratio,width ratio and number (single/twin) on bearing performance has been analyzed for a broad range of conditions.It was found that a careful tuning of the feeding conditions may indeed improve bearing performance.FCT - POCTI/EME/39202/200

    A coleção herpetológica das Faculdades Integradas do Tapajós/Faculdade da Amazônia, Santarém, Pará, Brasil: 1 - Répteis

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    It shows the collection of the herpetological collection of the Tapajos Integrated Colleges/College Amazon, with complete list of species of reptiles and amphibians deposited in the collection. The herpetological collection currently houses 3.349 specimens, has scientific and didactic collection. The entire collection is properly tumbled and packaged as minimum requirements for collections. He represents an excellent database for the study of amazon herpetofauna. The cities with the most representative specimens of deposits in the collection are Santarem and Belterra, Pará, Brazil; most copies come from scientific expeditions and be can considered a regional dynamic collection because it is to the community. However, greater investments are needed structural, for the maintenance and growth of, the collection so that it continues in of continue with the performance of their duties.Apresenta-se o acervo da coleção herpetológica das Faculdades Integradas do Tapajós/Faculdade da Amazônia, com lista completa das espécies de répteis depositados na coleção. A coleção herpetológica abriga atualmente 3.349 espécimes, possui coleção científica e didática. Todo o acervo está devidamente tombado e acondicionado conforme exigências mínimas para coleções. E representa uma excelente base de dados para o estudo da herpetofauna amazônica. As cidades com maior representatividade de depósitos de espécimes na coleção são Santarém e Belterra, Pará, Brasil. Grande parte dos exemplares é oriunda de expedições científicas e pode ser considerada uma coleção regional dinâmica, pois se encontra à disposição da comunidade. Entretanto, são necessários maiores investimentos de ordem estrutural, para a manutenção e crescimento do acervo, para que este continue no desempenho de suas funções

    Results from On-The-Ground Efforts to Promote Sustainable Cattle Ranching in the Brazilian Amazon

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    Agriculture in Brazil is booming. Brazil has the world’s second largest cattle herd and is the second largest producer of soybeans, with the production of beef, soybeans, and bioethanol forecast to increase further. Questions remain, however, about how Brazil can reconcile increases in agricultural production with protection of its remaining natural vegetation. While high hopes have been placed on the potential for intensification of low-productivity cattle ranching to spare land for other agricultural uses, cattle productivity in the Amazon biome (29% of the Brazilian cattle herd) remains stubbornly low, and it is not clear how to realize theoretical productivity gains in practice. We provide results from six initiatives in the Brazilian Amazon, which are successfully improving cattle productivity in beef and dairy production on more than 500,000 hectares of pastureland, while supporting compliance with the Brazilian Forest Code. Spread across diverse geographies, and using a wide range of technologies, participating farms have improved productivity by 30–490%. High-productivity cattle ranching requires some initial investment (R13006900/haorUS1300–6900/ha or US410–2180/ha), with average pay-back times of 2.5–8.5 years. We conclude by reflecting on the challenges that must be overcome to scale up these young initiatives, avoid rebound increases in deforestation, and mainstream sustainable cattle ranching in the Amazon

    Anticholinesterasic activity of Manilkara subsericea (Mart.) Dubard triterpenes

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    Manilkara subsericea (Mart.) Dubard (Sapotaceae) is popularly known in Brazil as "guracica". The species from the genus Manilkara have been studied and several substances were found, including triterpenes. In the present study, we describe the anticholinesterasic activity of an extract of M. subsericea containg beta-amyrin acetate (76.3 %) and alpha-amyrin acetate (23.7 %) using a TLC bioassay.Colegio de Farmacéuticos de la Provincia de Buenos Aire
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