929 resultados para year-class strength
Resumo:
This paper examines the relationship between attendance and grade, controlling for other factors, in first year economics courses in University College Cork. Determinants of both class attendance and grade are specified and estimated. We find that attendance is low, at least by comparison with US evidence. Hours worked and travel time are among the factors affecting class attendance. Class attendance, and especially tutorial attendance has a positive and diminishing marginal effect on grade, while hours worked in a part-time job have a significant negative effect on grade.
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A constructivist philosophy underlies the Irish primary mathematics curriculum. As constructivism is a theory of learning its implications for teaching need to be addressed. This study explores the experiences of four senior class primary teachers as they endeavour to teach mathematics from a constructivist-compatible perspective with primary school children in Ireland over a school-year period. Such a perspective implies that children should take ownership of their learning while working in groups on tasks which challenge them at their zone of proximal development. The key question on which the research is based is: to what extent will an exposure to constructivism and its implications for the classroom impact on teaching practices within the senior primary mathematics classroom in both the short and longer term? Although several perspectives on constructivism have evolved (von Glaserfeld (1995), Cobb and Yackel (1996), Ernest (1991,1998)), it is the synthesis of the emergent perspective which becomes pivotal to the Irish primary mathematics curriculum. Tracking the development of four primary teachers in a professional learning initiative involving constructivist-compatible approaches necessitated the use of Borko’s (2004) Phase 1 research methodology to account for the evolution in teachers’ understanding of constructivism. Teachers’ and pupils’ viewpoints were recorded using both audio and video technology. Teachers were interviewed at the beginning and end of the project and also one year on to ascertain how their views had evolved. Pupils were interviewed at the end of the project only. The data were analysed from a Jaworskian perspective i.e. using the categories of her Teaching Triad of management of learning, mathematical challenge and sensitivity to students. Management of learning concerns how the teacher organises her classroom to maximise learning opportunities for pupils. Mathematical challenge is reminiscent of the Vygotskian (1978) construct of the zone of proximal development. Sensitivity to students involves a consciousness on the part of the teacher as to how pupils are progressing with a mathematical task and whether or not to intervene to scaffold their learning. Through this analysis a synthesis of the teachers’ interpretations of constructivist philosophy with concomitant implications for theory, policy and practice emerges. The study identifies strategies for teachers wishing to adopt a constructivist-compatible approach to their work. Like O’Shea (2009) it also highlights the likely difficulties to be experienced by such teachers as they move from utilising teacher-dominated methods of teaching mathematics to ones in which pupils have more ownership over their learning.
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Experimental tests have been completed for high-strength 8.8 bolts for studying their mechanical performance subjected to tensile loading. As observed from these tests, failure of structural bolts has been identified as in one of two ways: threads stripping and necking of the threaded portion of the bolt shank, which is possibly due to the degree of fit between internal and external threads. Following the experimental work, a numerical approach has been developed for demonstration of the tensile performance with proper consideration of tolerance class between bolts and nuts. The degree of fit between internal and external threads has been identified as a critical factor affecting failure mechanisms of high-strength structural bolts in tension, which is caused by the machining process. In addition, different constitutive material laws have been taken into account in the numerical simulation, demonstrating the entire failure mechanism for structural bolts with different tolerance classes in their threads. It is also observed that the bolt capacities are closely associated with their failure mechanisms.
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BACKGROUND: -There are few contemporary data on the mortality and morbidity associated with rheumatic heart disease (RHD) or information on their predictors. We report the two year follow-up of individuals with RHD from 14 low and middle income countries in Africa and Asia.
METHODS: -Between January 2010 and November 2012, we enrolled 3343 patients from 25 centers in 14 countries and followed them for two years to assess mortality, congestive heart failure (CHF), stroke or transient ischemic attack (TIA), recurrent acute rheumatic fever (ARF), and infective endocarditis (IE).
RESULTS: -Vital status at 24 months was known for 2960 (88.5%) patients. Two thirds were female. Although patients were young (median age 28 years, interquartile range 18 to 40), the two year case fatality rate was high (500 deaths, 16.9%). Mortality rate was 116.3/1000 patient-years in the first year and 65.4/1000 patient-years in the second year. Median age at death was 28.7 years. Independent predictors of death were severe valve disease (hazard ratio (HR) 2.36, 95% confidence interval (CI) 1.80-3.11), CHF (HR 2.16, 95% CI 1.70-2.72), New York Heart Association functional class III/IV (HR 1.67, 95% CI 1.32-2.10), atrial fibrillation (AF) (HR 1.40, 95% CI 1.10-1.78) and older age (HR 1.02, 95% CI 1.01-1.02 per year increase) at enrolment. Post-primary education (HR 0.67, 95% CI 0.54-0.85) and female sex (HR 0.65, 95%CI 0.52-0.80) were associated with lower risk of death. 204 (6.9%) had new CHF (incidence, 38.42/1000 patient-years), 46 (1.6%) had a stroke or TIA (8.45/1000 patient-years), 19 (0.6%) had ARF (3.49/1000 patient-years), and 20 (0.7%) had IE (3.65/1000 patient-years). Previous stroke and older age were independent predictors of stroke/TIA or systemic embolism. Patients from low and lower-middle income countries had significantly higher age- and sex-adjusted mortality compared to patients from upper-middle income countries. Valve surgery was significantly more common in upper-middle income than in lower-middle- or low-income countries.
CONCLUSIONS: -Patients with clinical RHD have high mortality and morbidity despite being young; those from low and lower-middle income countries had a poorer prognosis associated with advanced disease and low education. Programs focused on early detection and treatment of clinical RHD are required to improve outcomes.
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The work presented in this catalogue represent ten years of study, thought, practice and application. While each member of the fourth-year visual arts class has selected just one image and chosen only a few words for inclusion in this record of our graduates and the program, it is important that we understand the dimensions of experience and learning symbolized on these pages. The women and men represented here have all passed through a rigorous course of academic study,personal and professional development, and technical training. They have engaged issues and concepts from both theoretical and practical perspectives, and have been challenged to stretch their thinking about community, society and the world in terms past, present and future. These Students have translated ideas and insights into works of art in a variety of media.
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One of the Highlights of our academic year is the exhibition of the works of the graduating class in our visual arts degree program. Of course it is very Satisfying to see such an unambiguous evidence of accomplishments of our students.But i also find the exhibition invariably inspiring because of the works themselves,which stimulate us to see again as children, with wide-eyed curiosity and wonder, without the need to explain or reduce, with delight, with horror, with recognition. In enabling us to see again in this way, the students have learned a very demanding craft and educated themselves inthe history, vocabulary and syntax of visual expression.
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Pipelines for the transport of crude oil from the production wells to the collecting stations are named production lines . These pipes are subjected to chemical and electrochemical corrosion according to the environment and the type of petroleum transported. Some of these lines, depending upon the composition of the fluid produced, may leak within less than one year of operation due to internal corrosion. This work aims at the development of composite pipes with an external protecting layer of high density polyurethane for use in production lines of onshore oil wells, meeting operational requirements. The pipes were manufactured using glass fibers, epoxy resin, polyester resin, quartz sand and high density polyurethane. The pipes were produced by filament winding with the deposition of high density polyurethane on the external surface and threaded ends (API 15 HR/PM-VII). Three types of pipes were manufactured: glass/epoxy, glass/epoxy with an external polyurethane layer and glass/epoxy with an intermediate layer of glass fiber, polyester, sand and with an external polyurethane layer. The three samples were characterized by Scanning Electronic Microscopy (SEM) and for the determination of constituent content. In addition, the following tests were conducted: hydrostatic test, instant rupture, shorttime failure pressure, Gardner impact, transverse stiffness and axial tension. Field tests were conducted in Mossoró RN (BRAZIL), where 1,677 meters of piping were used. The tests results of the three types of pipes were compared in two events: after two months from manufacturing of the samples and after nine months of field application. The results indicate that the glass/epoxy pipes with an intermediate layer of fiber glass composite, polyester e sand and with an external layer of high density polyurethane showed superior properties as compared to the other two and met the requirements of pressure class, axial tensile strength, transverse stiffness, impact and environmental conditions, for onshore applications as production lines
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Background: Choosing the method of nutritional assessment is essential for proper follow-up of the nutritional status of patients undergoing liver transplantation. Objectives: Evaluate and compare the nutritional status of cirrhotic patients before and after liver transplantation over a year by different methods of nutritional assessment. Methods: Patients undergoing liver transplantation were assessed in five phases: pre-transplant, 1, 3, 6 and 12 months after transplantation at the hospital Santa Casa de Misericordia de Porto Alegre, RS, Brazil. The methods used for nutritional assessment were anthropometry, grip strength of the non-dominant hand (HGS) by dynamometry, thickness of the adductor pollicis muscle (APM) and phase angle (PA) by bioelectrical impedance analysis (BIA). In all evaluations, the same measurements were taken. Results: Evaluations were performed in 22 patients. Methods that showed a higher prevalence of malnourished patients before transplantation were PA by BIA (25%), arm muscle circumference (AMC) (21.9%) and arm circumference (AC) (18.8%). When comparing the nutritional status of patients during follow-up, there was a significant difference only in the evaluation methods AC, triceps skinfold thickness and PA by BIA. At the end, the methods of nutritional assessment were compared again. They showed a significant statistical difference, with HGS being the best method for detecting malnutrition. Conclusions: In conclusion, it is suggested that the method PA by BIA could be widely used with this population since the results are consistent with other findings in the literature and they are significant, reliable, and reproducible.
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OBJECTIVE: To estimate the prevalence of spontaneous tinnitus in 11-year-old children. DESIGN: A prospective UK population-based study. STUDY SAMPLE: A total of 7092 children from the Avon longitudinal study of parents and children (ALSPAC) who attended the hearing session at age 11 years and answered questions about tinnitus. RESULTS: We estimated the prevalence of any spontaneous tinnitus as 28.1% (95% CI 27.1, 29.2%), and the prevalence of 'clinically significant' tinnitus as 3.1% (95% CI 2.7, 3.5%). Children were less likely to have clinically significant tinnitus if the tinnitus was 'soft' rather than 'loud' and if continuous rather than intermittent. Clinical significance was more likely if the tinnitus occurred more than once a week. Neither pitch nor length of history were important determinants of clinical significance. Small increases in mean hearing threshold (of up to 2.3 dB HL) were associated with clinically significant tinnitus. CONCLUSIONS: Although the prevalence of any tinnitus in 11-year-old children appears high, the small proportion in which this was found to be clinically significant implies that this does not necessarily indicate a large unmet clinical demand. We would expect approximately one child per class of 30 to have clinically significant tinnitus which is, by definition, problematic.
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Aims: Investigating tracking of fatness from childhood to adolescence, early adolescence to young adulthood and late adolescence to young adulthood. Subjects and methods: Participants from the Madeira Growth Study were followed during an average period of 7.2 years. Height, body mass, skin-folds and circumferences were measured, nine health- and performance-related tests were administered and the Baecke questionnaire was used to assess physical activity. Skeletal maturity was estimated using the TW3 method. Results: The prevalence of overweight plus obesity ranged from 8.2–20.0% at baseline and from 20.4–40.0% at followup, in boys. Corresponding percentages for girls were 10.6– 12.0% and 13.2–18.0%. Inter-age correlations for fatness indicators ranged from 0.43–0.77. BMI, waist circumference and sum of skin-folds at 8, 12 and 16-years old were the main predictors of these variables at 15, 19 and 23-years old, respectively. Strength, muscular endurance and aerobic fitness were negatively related to body fatness. Physical activity and maturation were independently associated with adolescent (15 years) and young adult (19 years) fatness. Conclusions: Over 7.2 years, tracking was moderate-to-high for fatness. Variance was explained by fatness indicators and to a small extent by physical fitness, physical activity and maturation.
Resumo:
Aims: Investigating tracking of fatness from childhood to adolescence, early adolescence to young adulthood and late adolescence to young adulthood. Subjects and methods: Participants from the Madeira Growth Study were followed during an average period of 7.2 years. Height, body mass, skin-folds and circumferences were measured, nine health- and performance-related tests were administered and the Baecke questionnaire was used to assess physical activity. Skeletal maturity was estimated using the TW3 method. Results: The prevalence of overweight plus obesity ranged from 8.2–20.0% at baseline and from 20.4–40.0% at followup, in boys. Corresponding percentages for girls were 10.6– 12.0% and 13.2–18.0%. Inter-age correlations for fatness indicators ranged from 0.43–0.77. BMI, waist circumference and sum of skin-folds at 8, 12 and 16-years old were the main predictors of these variables at 15, 19 and 23-years old, respectively. Strength, muscular endurance and aerobic fitness were negatively related to body fatness. Physical activity and maturation were independently associated with adolescent (15 years) and young adult (19 years) fatness. Conclusions: Over 7.2 years, tracking was moderate-to-high for fatness. Variance was explained by fatness indicators and to a small extent by physical fitness, physical activity and maturation.
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Abstract Objective: Evidence shows an association between muscular strength (MS) and health among youth, however low muscular strength cut-points for the detection of high metabolic risk in Latin-American populations are scarce. The aim of this study was two-fold: to explore potential age- and sex-specific thresholds of MS, for optimal cardiometabolic risk categorization among Colombian children and adolescents; and to investigate if cardiometabolic risk differed by MS group by applying the receiver operating characteristic curve (ROC) cut point. Methods: This is a secondary analysis of a cross-sectional study (the FUPRECOL study), published elsewhere. The FUPRECOL study assessments were conducted during the 2014– 2015 school year. MS was estimated by a handle dynamometer on 1,950 children and adolescents from Colombia, using the MS relative to weight (handgrip strength/body mass). A metabolic risk score was computed from the following components: waist circumference, triglycerides, HDL-c, glucose, systolic and diastolic blood pressure. ROC analysis showed a significant discriminatory accuracy of MS in identifying the low/high metabolic risk in children and adolescents and both gender. Results: In children, handgrip strength/body mass level for a low metabolic risk were 0.359 and 0.376 in girls and boys, respectively. In adolescents, these points were 0.440 and 0.447 in girls and boys, respectively. Conclusion: In conclusion, the results suggest a hypothetical MS level relative to weight for having a low metabolic risk, which could be used to identify youths at risk.
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Purpose: In the present study, we consider mechanical properties of phosphate glasses under high temperatureinduced and under friction-induced cross-linking, which enhance the modulus of elasticity. Design/methodology/approach: Two nanomechanical properties are evaluated, the first parameter is the modulus of elasticity (E) (or Young's modulus) and the second parameter is the hardness (H). Zinc meta-, pyro - and orthophosphates were recognized as amorphous-colloidal nanoparticles were synthesized under laboratory conditions and showed antiwear properties in engine oil. Findings: Young's modulus of the phosphate glasses formed under high temperature was in the 60-89 GPa range. For phosphate tribofilm formed under friction hardness and the Young's modulus were in the range of 2-10 GPa and 40-215 GPa, respectively. The degree of cross-linking during friction is provided by internal pressure of about 600 MPa and temperature close to 1000°C enhancing mechanical properties by factor of 3 (see Fig 1). Research limitations/implications: The addition of iron or aluminum ions to phosphate glasses under high temperature - and friction-induced amorphization of zinc metaphosphate and pyrophosphate tends to provide more cross-linking and mechanically stronger structures. Iron and aluminum (FeO4 or AlO4 units), incorporated into phosphate structure as network formers, contribute to the anion network bonding by converting the P=O bonds into bridging oxygen. Future work should consider on development of new of materials prepared by solgel processes, eg., zinc (II)-silicic acid. Originality/value: This paper analyses the friction pressure-induced and temperature–induced the two factors lead phosphate tribofilm glasses to chemically advanced glass structures, which may enhance the wear inhibition. Adding the coordinating ions alters the pressure at which cross-linking occurs and increases the antiwear properties of the surface material significantly.