1,376 research outputs found

    Effects of the construction of an educational mathematics game on students' attitudes and learning: Case study

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    Este trabalho descreve o processo de conceção e desenvolvimento de um jogo educativo de matemática denominado “Trivial matemático”, por alunos do 8.ºano de escolaridade, numa escola pública de Portugal, O jogo possibilita exercitar os mais variados conteúdos de matemática, através de pequenas adaptações, em qualquer ano de escolaridade do ensino básico. Neste trabalho investigou-se se a conceção de um jogo educativo promove a aprendizagem de conceitos matemáticos e identificaram-se implicações nas atitudes dos alunos face à matemática. A metodologia utilizada foi um design de estudo de caso. Trata-se de um estudo de caso misto pelo facto de existir uma combinação de instrumentos e técnicas, associadas aos estudos qualitativos e quantitativos. A recolha de dados, foi feita através da observação naturalista, da aplicação de tarefas e da aplicação de um inquérito por questionário. Na análise estatística dos dados foi utilizado o software SPSS. Os resultados obtidos sugerem que a utilização do jogo educativo, como recurso de apoio às aulas, produz uma melhoria significativa das atitudes dos alunos face à matemática, bem como, contribui para desenvolver a motivação dos alunos. Além disso, o processo de construção do jogo educativo aponta para uma melhoria na aprendizagem de conceitos geométricos inerentes ao jogoThis work describes the process of conception and development of an educational game of mathematics called "Mathematical Trivial", by students of the eighth grade of schooling, in a public school in Portugal. The game allows to practice the most varied mathematical contents through small adaptations, in any year of elementary education. In this work, we investigated whether the design of an educational game promotes the learning of mathematical concepts and identified the implications of students' attitudes towards mathematics. The methodology used was a case study design. This is a mixed case study because there is a combination of tools and techniques associated with qualitative and quantitative studies. The data collection was done through naturalistic observation, the application of tasks and the application of a questionnaire survey. Statistical analysis of the data was performed using SPSS software. The results suggest that the use of the educational game, as a resource to support the classes, produces a significant improvement of the students 'attitudes towards mathematics, as well as, it contributes to develop students' motivation. In addition, the process of constructing the educational game points to an improvement in the learning of geometrical concepts inherent to the game, in a playful and dynamic wa

    Pulsating Flow Effects on Hydrodynamics in a Desalination Membrane Filled with Spacers

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    A previously developed and validated two-dimensional computational fluid dynamics (CFD) model to study the hydrodynamics in a desalination membrane filled with spacers in zig-zag arrangements has been further developed to include the effects of a pulsating flow with the profile of a heartbeat. Numerical solutions were obtained with Fluent for pulsating laminar flows in channels filled with four different spacers and four lengths of cells. Hydrodynamics was investigated for unsteady state, using a characteristic function of a heartbeat, in order to study the influence of temporal variation in the hydrodynamic behavior. The results show the velocities distribution, streamlines, pressure drop and the wall shear stress on the impermeable wall of the membrane, for Reynolds numbers up to 100. The reduction in the distance between the filaments of the spacers, leads to the appearance of more active recirculation zones that can promote mass transfer and decreasing concentrations layers. On the other hand, this reduction increases the pressure drop and consequently the energy expended in the process. Further, the characteristic function of heartbeat demonstrates promising results, with regard to the energy consumption in the process and optimization of the recirculation zones

    Building Country-Specific Advantages (CSA): Understanding How FTZ Incentives Impact Strategic Plant Location and Buyer-Supplier Relationships

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    We explore how leading companies manage relationships in supply chains that are not formed by natural market forces. Rather, they were stimulated by exogenous forces, such as the Free Trade Zones that are created by the Government’s policy initiatives for purposes of regional development. We researched electronic industry in Manaus, located in the Brazilian Amazon Rain Forest. Multi-methods using qualitative, structured interviews, and quantitative approaches, structural modeling equation, were used. Results indicated that the companies settled for a location that they would not do under normal conditions and, secondly, that there was an expectation of externality as the makers of the strategy, in this case the public entity. Coordination among the members is not enough structured. No strategic supplier was found on the local FTZ, indicating that the local suppliers are only based on the premise of volume vs. logistics cost

    Machine learning for predicting fracture strain in sheet metal forming

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    Machine learning models are built to predict the strain values for which edge cracking occurs in hole expansion tests. The samples from this test play the role of sheet metal components to be manufactured, in which edge cracking often occurs associated with a uniaxial tension stress state at the critical edges of components. For the construction of the models, a dataset was obtained experimentally for rolled ferritic carbon steel sheets of different qualities and thicknesses. Two types of tests were performed: tensile and hole expansion tests. In the tensile test, the yield stress, the tensile strength, the strain at maximum load and the elongation after fracture were determined in the rolling and transverse directions. In the hole expansion test, the strain for which edge cracking occurs, was determined. It is intended that the models can predict the strain at fracture in this test, based on the knowledge of the tensile test data. The machine learning algorithms used were Multilayer Perceptron, Gaussian Processes, Support Vector Regression and Random Forest. The traditional polynomial regression that fits a 2nd order polynomial function was also used for comparison. It is shown that machine learning-based predictive models outperform the traditional polynomial regression method; in particular, Gaussian Processes and Support Vector Regression were found to be the best machine learning algorithms that enable the most robust predictive models.publishe

    Scaffold proteins LACK and TRACK as potential drug targets in kinetoplastid parasites: Development of inhibitors

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    Parasitic diseases cause similar to 500,000 deaths annually and remain a major challenge for therapeutic development. Using a rational design based approach, we developed peptide inhibitors with anti-parasitic activity that were derived from the sequences of parasite scaffold proteins LACK (Leishmania's receptor for activated C-kinase) and TRACK (Trypanosoma receptor for activated C-kinase). We hypothesized that sequences in LACK and TRACK that are conserved in the parasites, but not in the mammalian ortholog, RACK (Receptor for activated C-kinase), may be interaction sites for signaling proteins that are critical for the parasites' viability. One of these peptides exhibited leishmanicidal and trypanocidal activity in culture. Moreover, in infected mice, this peptide was also effective in reducing parasitemia and increasing survival without toxic effects. The identified peptide is a promising new anti-parasitic drug lead, as its unique features may limit toxicity and drug-resistance, thus overcoming central limitations of most anti-parasitic drugs. (C) 2016 The Authors. Published by Elsevier Ltd on behalf of Australian Society for Parasitology.National Institutes of HealthStanford Univ, Sch Med, Dept Chem & Syst Biol, Stanford, CA 94305 USAUniv Sao Paulo, Inst Quim, Dept Bioquim, BR-05508 Sao Paulo, SP, BrazilMcGill Univ, Res Inst, Natl Reference Ctr Parasitol, Montreal, PQ, CanadaUniv Autonoma Yucatan, Ctr Invest Reg Dr Hideyo Noguchi, Parasitol Lab, Merida, Yucatan, MexicoStanford Univ, Biomat & Adv Drug Delivery Lab, Stanford, CA 94305 USAUniv Estadual Campinas, Inst Chem, Campinas, SP, BrazilUniv Fed Sao Paulo, Dept Ciencias Biol, Campus Diadema, Sao Paulo, BrazilMcGill Univ, Inst Parasitol, Quebec City, PQ, CanadaMcGill Univ, Ctr Host Parasite Interact, Quebec City, PQ, CanadaUniv Fed Sao Paulo, Dept Ciencias Biol, Campus Diadema, Sao Paulo, BrazilNIH: TW008781-01C-IDEANIH: AI078505Web of Scienc

    A review of mycotoxins in food and feed products in Portugal and estimation of probable daily intakes

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    Mycotoxins are toxic secondary metabolites produced by filamentous fungi that occur naturally in agricultural commodities worldwide. Aflatoxins, ochratoxin A, patulin, fumonisins, zearalenone, trichothecenes and ergot alkaloids are presently the most important for food and feed safety. These compounds are produced by several species that belong to the Aspergillus, Penicillium, Fusarium and Claviceps genera and can be carcinogenic, mutagenic, teratogenic, cytotoxic, neurotoxic, nephrotoxic, estrogenic and immunosuppressant. Human and animal exposure to mycotoxins is generally assessed by taking into account data on the occurrence of mycotoxins in food and feed as well as data on the consumption patterns of the concerned population. This evaluation is crucial to support measures to reduce consumer exposure to mycotoxins. This work reviews the occurrence and levels of mycotoxins in Portuguese food and feed to provide a global overview of this issue in Portugal. With the information collected, the exposure of the Portuguese population to those mycotoxins is assessed, and the estimated dietary intakes are presented.Lu ıs Abrunhosa, H ector Morales, C elia Soares, and Thalita Calado received support through grants SFRH/BPD/43922/ 2008, SFRH/BPD/38011/2007, SFRH/BD/37264/2007 and SFRH/BD/79364/2011, respectively, from the Fundac¸ ao para ~ a Ciencia e Tecnologia ^ –FCT, Portugal

    Impact of promoting self-care in nursing workload

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    Abstract OBJECTIVES To assess the impact of promoting self-care in nursing workload and associate it to the variables: age, gender, socioeconomic status, education, marital status and number of children of caregivers. METHODS Prospective study with 31 children and their caregivers. Participants were assessed at two moments, 1st and 2nd hospitalization, the nursing workload was measured by the Nursing Activities Score (NAS). RESULTS The mean NAS in the 1st hospitalization was 60.9% and in the 2nd hospitalization was 41.6%, that is, 14.6 and 9.9 hours of nursing, respectively. The nursing workload on the first day of hospitalization was higher compared to the last day, both for the 1st (p<0.001) and for the 2nd hospitalization (p<0.001), and higher in the first (p<0.001) and in the last day (p=0.025) in the 1st hospitalization. Comparing the 1st hospitalization to the 2nd hospitalization, the first was higher (p<0.001), and NAS items related to the training of self-care was influenced (p<0.001). CONCLUSION The nursing workload associated to self-care promotion corresponded to 14.6 hours and was higher than determined by the existing legislation

    Adjunctive rifampicin to reduce early mortality from Staphylococcus aureus bacteraemia: the ARREST RCT.

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    BACKGROUND: Staphylococcus aureus bacteraemia is a common and frequently fatal infection. Adjunctive rifampicin may enhance early S. aureus killing, sterilise infected foci and blood faster, and thereby reduce the risk of dissemination, metastatic infection and death. OBJECTIVES: To determine whether or not adjunctive rifampicin reduces bacteriological (microbiologically confirmed) failure/recurrence or death through 12 weeks from randomisation. Secondary objectives included evaluating the impact of rifampicin on all-cause mortality, clinically defined failure/recurrence or death, toxicity, resistance emergence, and duration of bacteraemia; and assessing the cost-effectiveness of rifampicin. DESIGN: Parallel-group, randomised (1 : 1), blinded, placebo-controlled multicentre trial. SETTING: UK NHS trust hospitals. PARTICIPANTS: Adult inpatients (≥ 18 years) with meticillin-resistant or susceptible S. aureus grown from one or more blood cultures, who had received < 96 hours of antibiotic therapy for the current infection, and without contraindications to rifampicin. INTERVENTIONS: Adjunctive rifampicin (600-900 mg/day, oral or intravenous) or placebo for 14 days in addition to standard antibiotic therapy. Investigators and patients were blinded to trial treatment. Follow-up was for 12 weeks (assessments at 3, 7, 10 and 14 days, weekly until discharge and final assessment at 12 weeks post randomisation). MAIN OUTCOME MEASURES: The primary outcome was all-cause bacteriological (microbiologically confirmed) failure/recurrence or death through 12 weeks from randomisation. RESULTS: Between December 2012 and October 2016, 758 eligible participants from 29 UK hospitals were randomised: 370 to rifampicin and 388 to placebo. The median age was 65 years [interquartile range (IQR) 50-76 years]. A total of 485 (64.0%) infections were community acquired and 132 (17.4%) were nosocomial; 47 (6.2%) were caused by meticillin-resistant S. aureus. A total of 301 (39.7%) participants had an initial deep infection focus. Standard antibiotics were given for a median of 29 days (IQR 18-45 days) and 619 (81.7%) participants received flucloxacillin. By 12 weeks, 62 out of 370 (16.8%) patients taking rifampicin versus 71 out of 388 (18.3%) participants taking the placebo experienced bacteriological (microbiologically confirmed) failure/recurrence or died [absolute risk difference -1.4%, 95% confidence interval (CI) -7.0% to 4.3%; hazard ratio 0.96, 95% CI 0.68 to 1.35; p = 0.81]. There were 4 (1.1%) and 5 (1.3%) bacteriological failures (p = 0.82) in the rifampicin and placebo groups, respectively. There were 3 (0.8%) versus 16 (4.1%) bacteriological recurrences (p = 0.01), and 55 (14.9%) versus 50 (12.9%) deaths without bacteriological failure/recurrence (p = 0.30) in the rifampicin and placebo groups, respectively. Over 12 weeks, there was no evidence of differences in clinically defined failure/recurrence/death (p = 0.84), all-cause mortality (p = 0.60), serious (p = 0.17) or grade 3/4 (p = 0.36) adverse events (AEs). However, 63 (17.0%) participants in the rifampicin group versus 39 (10.1%) participants in the placebo group experienced antibiotic or trial drug-modifying AEs (p = 0.004), and 24 (6.5%) participants in the rifampicin group versus 6 (1.5%) participants in the placebo group experienced drug-interactions (p = 0.0005). Evaluation of the costs and health-related quality-of-life impacts revealed that an episode of S. aureus bacteraemia costs an average of £12,197 over 12 weeks. Rifampicin was estimated to save 10% of episode costs (p = 0.14). After adjustment, the effect of rifampicin on total quality-adjusted life-years (QALYs) was positive (0.004 QALYs), but not statistically significant (standard error 0.004 QALYs). CONCLUSIONS: Adjunctive rifampicin provided no overall benefit over standard antibiotic therapy in adults with S. aureus bacteraemia. FUTURE WORK: Given the substantial mortality, other antibiotic combinations or improved source management should be investigated. TRIAL REGISTRATIONS: Current Controlled Trials ISRCTN37666216, EudraCT 2012-000344-10 and Clinical Trials Authorisation 00316/0243/001. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 59. See the NIHR Journals Library website for further project information.NIHR HTA Programm
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