827 resultados para Verification and validation technology
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This qualitative study was aimed at investigating foreign language teachers’ attitudes toward use of information and communication technology (ICT) in their instruction. The insight was gained through the reported experience of ICT implementation by teachers, in what way and for which purpose they refer to use of technology, what kind of support and training they are provided with, and what beliefs they express about the influence of ICT implementation. This case study took place in one of the training schools in Finland. Five teachers participated in semi-structured interviews through a face-to-face approach. The findings demonstrated positive attitudes of teachers toward integration of ICT. The teachers shared their opinions about positive influence that ICT implementation has on both teaching and learning processes. However, they also pointed out the negative sides of ICT use: distraction of the students from usage of technology and technical problems causing frustration to the teachers. In addition, the responses revealed that the teachers are provided with adequate training aimed at enhancing their qualification which is provided with well-timed technology support and colleagues’ collaboration facilitating an efficient and smooth pace of the teaching process. According to the teachers’ opinions ICT integration in education appeared to have changed the role of the teacher. Due to different alterations in the field of ICT development teachers are required to upgrade their skills. The paper concludes with the limitations of the study and the recommendations for conducting further research.
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Background: The nitration of tyrosine residues in proteins is associated with nitrosative stress, resulting in the formation of 3-nitrotyrosine (3-NT). 3-NT levels in biological samples have been associated with numerous physiological and pathological conditions. For this reason, several attempts have been made in order to develop methods that accurately quantify 3-NT in biological samples. Regarding chromatographic methods, they seem to be very accurate, showing very good sensibility and specificity. However, accurate quantification of this molecule, which is present at very low concentrations both at physiological and pathological states, is always a complex task and a target of intense research. Objectives: We aimed to develop a simple, rapid, low-cost and sensitive 3-NT quantification method for use in medical laboratories as an additional tool for diagnosis and/or treatment monitoring of a wide range of pathologies. We also aimed to evaluate the performance of the HPLC-based method developed here in a wide range of biological matrices. Material and methods: All experiments were performed on a Hitachi LaChrom Elite® HPLC system and separation was carried out using a Lichrocart® 250-4 Lichrospher 100 RP-18 (5μm) column. The method was further validated according to ICH guidelines. The biological matrices tested were serum, whole blood, urine, B16 F-10 melanoma cell line, growth medium conditioned with the same cell line, bacterial and yeast suspensions. Results: From all the protocols tested, the best results were obtained using 0.5% CH3COOH:MeOH:H2O (15:15:70) as the mobile phase, with detection at wavelengths 215, 276 and 356 nm, at 25ºC, and using a flow rate of 1 mL/min. By using this protocol, it was possible to obtain a linear calibration curve (correlation coefficient = 1), limits of detection and quantification in the order of ng/mL, and a short analysis time (<15 minutes per sample). Additionally, the developed protocol allowed the successful detection and quantification of 3-NT in all biological matrices tested, with detection at 356 nm. Conclusion: The method described in this study, which was successfully developed and validated for 3-NT quantification, is simple, cheap and fast, rendering it suitable for analysis in a wide range of biological matrices.
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This paper presents the results of the implementation of a self-consumption maximization strategy tested in a real-scale Vanadium Redox Flow Battery (VRFB) (5 kW, 60 kWh) and Building Integrated Photovoltaics (BIPV) demonstrator (6.74 kWp). The tested energy management strategy aims to maximize the consumption of energy generated by a BIPV system through the usage of a battery. Whenever possible, the residual load is either stored in the battery to be used later or is supplied by the energy stored previously. The strategy was tested over seven days in a real-scale VRF battery to assess the validity of this battery to implement BIPV-focused energy management strategies. The results show that it was possible to obtain a self-consumption ratio of 100.0%, and that 75.6% of the energy consumed was provided by PV power. The VRFB was able to perform the strategy, although it was noticed that the available power (either to charge or discharge) varied with the state of charge.
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Background: Appetite and symptoms, conditions generally reported by the patients with cancer, are somewhat challenging for professionals to measure directly in clinical routine (latent conditions). Therefore, specific instruments are required for this purpose. This study aimed to perform a cultural adaptation of the Cancer Appetite and Symptom Questionnaire (CASQ), into Portuguese and evaluate its psychometric properties on a sample of Brazilian cancer patients. Methods: This is a validation study with Brazilian cancer patients. The face, content, and construct (factorial and convergent) validities of the Cancer Appetite and Symptom Questionnaire, the study tool, were estimated. Further, a confirmatory factor analysis (CFA) was conducted. The ratio of chi-square and degrees of freedom (χ2/df), comparative fit index (CFI), goodness of fit index (GFI) and root mean square error of approximation (RMSEA) were used for fit model assessment. In addition, the reliability of the instrument was estimated using the composite reliability (CR) and Cronbach’s alpha coefficient (α), and the invariance of the model in independent samples was estimated by a multigroup analysis (Δχ2). Results: Participants included 1,140 cancer patients with a mean age of 53.95 (SD = 13.25) years; 61.3% were women. After the CFA of the original CASQ structure, 2 items with inadequate factor weights were removed. Four correlations between errors were included to provide adequate fit to the sample (χ2/df = 8.532, CFI = .94, GFI = .95, and RMSEA = .08). The model exhibited a low convergent validity (AVE = .32). The reliability was adequate (CR = .82 α = .82). The refined model showed strong invariance in two independent samples (Δχ2: λ: p = .855; i: p = .824; Res: p = .390). A weak stability was obtained between patients undergoing chemotherapy and radiotherapy (Δχ2: λ: p = .155; i: p < .001; Res: p < .001), and between patients undergoing chemotherapy combined with radiotherapy and palliative care (Δχ2: λ: p = .058; i: p < .001; Res: p < .001). Conclusion: The Portuguese version of the CASQ had good face and construct validity and reliability. However, the CASQ still presented invariance in independent samples of Brazilian patients with cancer. However, the tool has low convergent validity and weak invariance in samples with different treatments.
Resumo:
This qualitative study was aimed at investigating foreign language teachers’ attitudes toward use of information and communication technology (ICT) in their instruction. The insight was gained through the reported experience of ICT implementation by teachers, in what way and for which purpose they refer to use of technology, what kind of support and training they are provided with, and what beliefs they express about the influence of ICT implementation. This case study took place in one of the training schools in Finland. Five teachers participated in semi-structured interviews through a face-to-face approach. The findings demonstrated positive attitudes of teachers toward integration of ICT. The teachers shared their opinions about positive influence that ICT implementation has on both teaching and learning processes. However, they also pointed out the negative sides of ICT use: distraction of the students from usage of technology and technical problems causing frustration to the teachers. In addition, the responses revealed that the teachers are provided with adequate training aimed at enhancing their qualification which is provided with well-timed technology support and colleagues’ collaboration facilitating an efficient and smooth pace of the teaching process. According to the teachers’ opinions ICT integration in education appeared to have changed the role of the teacher. Due to different alterations in the field of ICT development teachers are required to upgrade their skills. The paper concludes with the limitations of the study and the recommendations for conducting further research.
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Nowadays the organizational scenario is changing in several aspects that affect organization commitment. Team learning construct has emerged as a tool to deal with these changes and the dynamic nature of this situation. Although team learning has acquired importance in recent years, instruments to measure team learning should be developed. The aim of this paper is to develop and validate a team learning scale, the Team Learning Questionnaire, attending to four dimensions of team learning: Continued Improvement Seeking, Dialogue Promotion and Open Communication, Collaborative Learning, and Strategic and Proactive Leadership that Promote Learning. Results provide evidence of the reliability and validity of the scale.
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International audience
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This study presents the development and analysis of the psychometric properties of the Deviant Behavior Variety Scale (DBVS). Participants were 861 Portuguese adolescents (54 % female), aged between 12 and 19 years old. Two alternative models were tested using Confirmatory Factor Analysis. Although both models showed good fit indexes, the two-factor model didn’t presented discriminant validity. Further results provided evidence for the factorial and the convergent validity of the single-factor structure of the DVBS, which has also shown good internal consistency. Criterion validity was evaluated through the association with related variables, such as age and school failure, as well as the scale’s ability to capture group differences, namely between genders and school retentions, and finally by comparing a sub-group of convicted adolescents with a group of non-convicted ones regarding their engagement in delinquent activities. Overall, the scale presented good psychometric properties, with results supporting that the DBVS is a valid and reliable self-reported measure to evaluate adolescents’ involvement in deviance.
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Invasive candidiasis (IC) is an opportunistic systemic mycosis caused by Candida species (commonly Candida albicans) that continues to pose a significant public health problem worldwide. Despite great advances in antifungal therapy and changes in clinical practices, IC remains a major infectious cause of morbidity and mortality in severely immunocompromised or critically ill patients, and further accounts for substantial healthcare costs. Its impact on patient clinical outcome and economic burden could be ameliorated by timely initiation of appropriate antifungal therapy. However, early detection of IC is extremely difficult because of its unspecific clinical signs and symptoms, and the inadequate accuracy and time delay of the currently available diagnostic or risk stratification methods. In consequence, the diagnosis of IC is often attained in advanced stages of infection (leading to delayed therapeutic interventions and ensuing poor clinical outcomes) or, unfortunately, at autopsy. In addition to the difficulties encountered in diagnosing IC at an early stage, the initial therapeutic decision-making process is also hindered by the insufficient accuracy of the currently available tools for predicting clinical outcomes in individual IC patients at presentation. Therefore, it is not surprising that clinicians are generally unable to early detect IC, and identify those IC patients who are most likely to suffer fatal clinical outcomes and may benefit from more personalized therapeutic strategies at presentation. Better diagnostic and prognostic biomarkers for IC are thus needed to improve the clinical management of this life-threatening and costly opportunistic fungal infection...
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Background and aims: A gluten-free diet is to date the only treatment available to celiac disease sufferers. However, systematic reviews indicate that, depending on the method of evaluation used, only 42% to 91% of patients adhere to the diet strictly. Transculturally adapted tools that evaluate adherence beyond simple self-informed questions or invasive analyses are, therefore, of importance. The aim is to obtain a Spanish transcultural adaption and validation of Leffler's Celiac Dietary Adherence Test. Methods: A two-stage observational transversal study: translation and back translation by four qualified translators followed by a validation stage in which the questionnaire was administered to 306 celiac disease patients aged between 12 and 72 years and resident in Aragon. Factorial structure, criteria validity and internal consistency were evaluated. Results: The Spanish version maintained the 7 items in a 3-factor structure. Feasibility was very high in all the questions answered and the floor and ceiling effects were very low (4.3% and 1%, respectively). The Spearman correlation with the self-efficacy and life quality scales and the self-informed question were statistically significant (p < 0.01). According to the questionnaire criteria, adherence was 72.3%. Conclusion: The Spanish version of the Celiac Dietary Adherence Test shows appropriate psychometric properties and is, therefore, suitable for studying adherence to a gluten-free diet in clinical and research environments.
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The optical access engine integrated with the diagnostic and optical measurement techniques is a great platform for engine research because it provides clear visual access to the combustion chamber inside the engines. An optical access engine customized based on a 4-cylinder spark ignited direct injection (SIDI) production engine is located in the Advanced Power Systems Laboratories (APS LABS) at Michigan Technological University. This optical access engine inside the test cell has been set up for different engine research. In this report, two SAE papers in engine research utilizing the optical access engine are reviewed to gain basic understanding of the methodology. Though the optical engine in APS LABS is a little bit different from the engines used in the literature, the methodology in the papers provides guidelines for engine research through optical access engines. In addition, the optical access engine instrumentation including the test cell setup and the optical engine setup is described in detail in the report providing a solid record for later troubleshooting and reference. Finally, the motoring tests, firing tests and optical imaging experiment on the optical engine have been performed to validate the instrumentation. This report only describes so far the instrumentation of the optical engine in the APS LABS by April 2015.
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Tropical Rainfall Measuring Mission (TRMM) rainfall retrieval algorithms are evaluated in tropical cyclones (TCs). Differences between the Precipitation Radar (PR) and TRMM Microwave Imager (TMI) retrievals are found to be related to the storm region (inner core vs. rainbands) and the convective nature of the precipitation as measured by radar reflectivity and ice scattering signature. In landfalling TCs, the algorithms perform differently depending on whether the rainfall is located over ocean, land, or coastal surfaces. Various statistical techniques are applied to quantify these differences and identify the discrepancies in rainfall detection and intensity. Ground validation is accomplished by comparing the landfalling storms over the Southeast US to the NEXRAD Multisensor Precipitation Estimates (MPE) Stage-IV product. Numerous recommendations are given to algorithm users and developers for applying and interpreting these algorithms in areas of heavy and widespread tropical rainfall such as tropical cyclones.
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Adjuvants are substances that boost the protective immune response to vaccine antigens. The majority of known adjuvants have been identified through the use of empirical approaches. Our aim was to identify novel adjuvants with well-defined cellular and molecular mechanisms by combining a knowledge of immunoregulatory mechanisms with an in silico approach. CD4 + CD25 + FoxP3 + regulatory T cells (Tregs) inhibit the protective immune responses to vaccines by suppressing the activation of antigen presenting cells such as dendritic cells (DCs). In this chapter, we describe the identification and functional validation of small molecule antagonists to CCR4, a chemokine receptor expressed on Tregs. The CCR4 binds the chemokines CCL22 and CCL17 that are produced in large amounts by activated innate cells including DCs. In silico identified small molecule CCR4 antagonists inhibited the migration of Tregs both in vitro and in vivo and when combined with vaccine antigens, significantly enhanced protective immune responses in experimental models.
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This short paper presents a numerical method for spatial and temporal downscaling of solar global radiation and mean air temperature data from global weather forecast models and its validation. The final objective is to develop a prediction algorithm to be integrated in energy management models and forecast of energy harvesting in solar thermal systems of medium/low temperature. Initially, hourly prediction and measurement data of solar global radiation and mean air temperature were obtained, being then numerically downscaled to half-hourly prediction values for the location where measurements were taken. The differences between predictions and measurements were analyzed for more than one year of data of mean air temperature and solar global radiation on clear sky days, resulting in relative daily deviations of around -0.9±3.8% and 0.02±3.92%, respectively.