The effective use of student time: a stochastic frontier production function case study     

Peter Dolton  Oscar D. Marcenaro  Lucia Navarro 《Economics of Education Review》2003,22(6):547-560

The relationship between student study time allocation and examination performance is little understood. We model the allocation of student time into formal study (lectures and classes) and self study and its relationship to university examination scores using a stochastic frontier production function. This case study uses unique time budget data and detailed personal records from one university in Spain. The results suggest that, within the formal system of teaching in Spain, both formal study and self study are significant determinants of exam scores but that the former may be up to four times more important than the latter. We also find that self study time may be insignificant if ability bias is corrected for.  相似文献   

Risk Assessment and Preservative Measures for Volatile Organic Compounds in Museum Showcases     

Oscar Chiantore  Chiara Riedo  Tommaso Poli  Giancarlo Cotrufo  Peter Hohenstatt 《文物保护研究》2018,63(5):58-63

ABSTRACT

The first step in preservative measures for artworks in airtight showcases is the exclusion of outgassing from construction materials or, at least, limitation of the emissions to a minimum acceptable level if the volatile organic compounds (VOCs) generated may be qualified as harmless. Once it is ascertained that the objects in the showcases are responsible for VOC emissions, a step forward becomes necessary, implying showcase ventilation with air flowing through active sorbent materials. Solid phase micro-extraction (SPME) followed by GC separation and MS identification has been applied for checking the outgassing characteristics of different types of materials used for the construction of airtight showcases, and the method was found particularly attractive in terms of speed and sensitivity, suitable for measurements in presence of low-emitting materials. Sampling could also be done in the case interiors, thus making possible detection and recognition of emissions from art objects within a case. A comprehensive preventive conservation scheme has been further devised by means of active air circulation within the showcase and functional sorbent materials along the flow, for complete suppression of gaseous compounds. Control of the compounds in the air flow and of their filtration efficacy was achieved by direct sampling, also using SPME fibers. Continuous monitoring of the air quality in the showcases has been developed with insertion of a photoionization detector capable of detecting the VOCs in the air by inducing molecular ionization, and measuring the generated photocurrent. The system is not selective, but gives the total concentration, reaching ppb sensitivity with high-quality data. In addition it includes temperature and humidity sensors, making the whole a useful instrument for environment control.  相似文献   

Activity-related typologies and longitudinal change in physical activity and sedentary time in children and adolescents: The UP&DOWN Study     

Kate Parker  Anna Timperio  Jo Salmon  Karen Villanueva  Helen Brown  Irene Esteban-Cornejo  Veronica Cabanas-Snchez  Jos Castro-Piero  David Snchez-Oliva  Oscar L. Veiga 《运动与健康科学(英文)》2021,10(4):447

BackgroundChildren and adolescents can be distinguished by different typologies (clusters) of physical activity and sedentary behavior. How physical activity and sedentary behaviors change over time within different typologies is not known. This study examined longitudinal changes in physical activity and sedentary time among children and adolescents with different baseline typologies of activity-related behavior.MethodsIn this longitudinal study (3 annual time points) of children (n = 600, age = 9.2 ± 0.4 years (mean ± SD), 50.3% girls) and adolescents (n = 1037, age = 13.6 ± 1.7 years, 48.4% girls), participants were recruited in Spain in 2011–2012. Latent class analyses identified typologies based on self-reported screen, educational, social and relaxing sedentary behaviors, active travel, muscle strengthening activity, and sport at baseline. Within each typology, linear mixed growth models explored longitudinal changes in accelerometer-derived moderate-to-vigorous physical activity and sedentary time, as well as time by class interactions.ResultsThree typologies were identified among children (“social screenies”, 12.8%; “exercisers”, 61.5%; and “non-sporty active commuters”, 25.7%) and among adolescents (“active screenies”, 43.5%; “active academics”, 35.0%; and “non-sporty active commuters”, 21.5%) at baseline. Sedentary time increased within each typology among children and adolescents, with no significant differences between typologies. No changes in physical activity were found in any typology among children. In adolescents, physical activity declined within all typologies, with “non-sporty active commuters” declining significantly more than “active screenies” over 3 years.ConclusionThese results support the need for intervention to promote physical activity and prevent increases in sedentary time during childhood and adolescence. Adolescents characterized as “non-sporty active commuters” may require specific interventions to maintain their physical activity over time.  相似文献   

Relationship Between Educational Resources and School Achievement: A Mixed Method Intra-District Analysis     

Oscar Jimenez-Castellanos 《The Urban Review》2010,42(4):351-371

This study examines the relationship between educational resources (fiscal, personnel and facilities) and school achievement within a large urban/suburban elementary school district. A sequential mixed methods approach reveals inequitable resource allocation trends and patterns between schools within a school district by producing different student outcomes. The educational resources positively correlated to higher school achievement are: higher teacher salaries, newer schools, more multi-purpose space per pupil and less portable classrooms. Without question, White students receive more of these resources than Latino students, low-income students and English Language learners. This study also conducts a multiple comparative case study analysis comparing between Title I and non-Title I schools, within Title I schools and within non-Title I schools. The study contains policy and practice implications to improve opportunity and school achievement in urban/suburban school districts.  相似文献   

The government irrigation project at roosevelt dam,salt river,Arizona     

Oscar C.S. Carter 《Journal of The Franklin Institute》1907,163(4):277-301

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Emigration and the supply and demand for medical manpower: The Irish case     

Oscar Gish 《Minerva》1969,7(4):668-679

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Connecting others: Does a tertius iungens orientation shape the relationship between research networks and innovation?     

Oscar Llopis  Pablo D'Este  Adrián A. Díaz-Faes 《Research Policy》2021,50(4):104175

Research on social networks and innovation emphasizes that individuals spanning structural holes and crossing institutional boundaries have more opportunities for knowledge recombination and innovation involvement. However, transforming the potential knowledge and resources available through personal networks to attain innovation can be difficult for the focal individual. Using an ego-network approach, this study examines whether and to what extent an individual strategic orientation to cooperation (i.e. tertius iungens) contributes to strengthening the relation between two personal network properties (structural and institutional separation) and involvement in innovation. Our analysis is conducted in the context of biomedicine, where research networks are particularly relevant for science and innovation achievements. Our findings advance social network theory by decoupling social network mechanisms from individual strategic networking behavior as factors influencing knowledge generation processes. Results also provide original evidence on an overlooked phenomenon: the moderating role of a tertius iungens orientation in the relationship between multiple social network properties and innovation. Finally, our research sheds new light on the distinct sources of knowledge recombination in networks and the role of individual networking strategies to facilitate mobilization of resources for innovation.  相似文献   

Reacting to poverty: A comparative analysis of schools in Brazilian deprived areas     

Aina Tarabini  Xavier Bonal  Oscar Valiente 《Prospects》2014,44(3):335-349

Schools in the most deprived areas in Brazil are marked by extreme poverty, a situation that has obvious consequences for the everyday life in schools and for efforts to develop a supportive culture of schooling. Nevertheless, schools’ responses to poverty are far from uniform. Although the context of poverty generally determines what is possible for schools to achieve, this context is by no means consistent. Not all schools located in poor areas offer poor education. And, in themselves, unfavourable contexts do not necessarily generate educational failure. This article captures the diversity of effects generated by poverty at the school level, and the variety of responses by schools situated in very similar socioeconomic and cultural contexts. It draws on a study conducted in the state of Minas Gerais, which explored five schools and their corresponding cultures to reveal the diverse effects of poverty at the school level.  相似文献   

Children's shyness,popularity, school liking,cooperative participation,and internalizing problems in the early school years     

Natalie D. Eggum-Wilkens  Carlos Valiente  Jodi Swanson  Kathryn Lemery-Chalfant 《Early childhood research quarterly》2014

Aims of the present study included understanding the manner in which shyness during the first year of formal schooling predicts early popularity in the peer group, as well as the manner in which children's shyness and popularity uniquely contribute to later school liking, cooperative participation, and internalizing problems. Structural equation modeling using parents’, teachers’, and children's reports suggested that children's (N = 291; 46% girls) kindergarten shyness predicted lower school liking and lower cooperative participation during second grade through its negative association with first grade popularity. Shyness during the first year of formal schooling may relate to difficulties in the classroom during later years due to problematic peer relations. The indirect relation of kindergarten shyness to second-grade internalizing problems through first-grade popularity was not statistically significant. Kindergarten shyness was also directly related to higher cooperative participation, which suggests that relations between early shyness and classroom engagement may be more complex than previously assumed.  相似文献   

Journalism     

Howard Simons  Joseph A. Califano Jr.  Oscar H. Gandy  George S. Rage  William A. Lucas  Karen B. Possner 《Communication Booknotes Quarterly》2013,44(7):86-87

Howard Simons and Joseph A. Califano, Jr. (eds.) The Media and the Law (New York: Praeger Special Studies, 1976---$4.95, paper with hardbound edition available)

Oscar H. Gandy, et al. Media and Government: An Annotated Bibliography (Institute for Communisation Research, Stanford University, Stanford, Calif. 94305--- apparently free on request, paper)

George S. Rage, et al. New Strategies for Public Affairs Reporting: Investigation, Interpretation, and Research (Englewood Cliffs, N.J.: Prentice-Hall, 1976---price not given)

William A. Lucas and Karen B. Possner's Television News and Local Awareness: A Retrospective Look (Santa Monica, Calif.: Rand Corp. R-1858-MF, 1975---$5.00, paper)

Judith S. Gelfman's Women in Television News (New York: Columbia University Press, 1976---$7.95)  相似文献