Higher socioeconomic status is related to healthier levels of fatness and fitness already at 3 to 5 years of age: The PREFIT project     

Ignacio Merino-De Haro  Cristina Cadenas-Sanchez  Pere A. Borras  Pedro J. Benito  Oscar Chiva-Bartoll 《Journal of sports sciences》2019,37(12):1327-1337

This study aimed to analyse the association between socioeconomic status (SES) and fatness and fitness in preschoolers. 2,638 preschoolers (3–5 years old; 47.2% girls) participated. SES was estimated from the parental educational and occupational levels, and the marital status. Fatness was assessed by body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR). Physical fitness components were assessed using the PREFIT battery. Preschoolers whose parents had higher educational levels had lower fatness (P < 0.05). BMI significantly differed across occupational levels of each parent (P < 0.05) and WHtR across paternal levels (P = 0.004). Musculoskeletal fitness was different across any SES factor (P < 0.05), except handgrip across paternal occupational levels (P ≥ 0.05). Preschoolers with high paternal occupation had higher speed/agility (P = 0.005), and those with high or low maternal education had higher VO₂max (P = 0.046). Odds of being obese and having low musculoskeletal fitness was lower as SES was higher (P < 0.05). Those with married parents had higher cardiorespiratory fitness than single-parent ones (P = 0.010). School-based interventions should be aware of that children with low SES are at a higher risk of obesity and low fitness already in the first years of life.  相似文献   

Developing teachers’ pedagogical identities through a community of practice: learning to sustain the use of a student-centered inquiry as curriculum approach     

Carla Luguetti  Raquel Aranda  Oscar Nuñez Enriquez  Kimberly L. Oliver 《Sport, Education and Society》2013,18(8):855-866

ABSTRACT

This collaborative self-study explores how educators’ pedagogical identities developed in the process of learning to use a Student-Centered Inquiry as Curriculum (SCIC) approach in activity settings within a community of practice (CoP). Participants included a university professor, college instructor, postdoctoral student and doctoral student. Data included 16 weekly field notes and debriefings following observations, teacher artifacts, 16 weekly collaborative group meetings, and 3 90-minute interviews per teacher. Culture, values, beliefs and professional background were critical for the development of the teachers’ pedagogical identities in the process of learning to use a SCIC approach within a community of practice. These experiences created for some, places to further develop their ideas about teaching, whereas for others they caused great discomfort and a sense of personal loss. The CoP facilitated the development of the teachers’ pedagogical identities, changing positionalities, and negotiating culture, values, beliefs and professional backgrounds.  相似文献   

The impact of test language on PISA scores. New evidence from Wales     

John Jerrim  Luis Alejandro Lopez-Agudo  Oscar David Marcenaro-Gutierrez 《British Educational Research Journal》2022,48(3):420-445

In this paper we investigate the link between the language in which pupils take the Programme for International Student Assessment (PISA) test and the scores they achieve in this assessment, focusing upon the case of Wales. Using five rounds of PISA data and an instrumental variable approach, we show how pupils who took the test in Welsh score around 0.3 standard deviations (30 PISA test points) lower in reading, mathematics and science than their peers who took the test in English. This finding is robust to different model specifications and statistical approaches. We argue that this may indicate that the academic performance of teenagers in Wales may be underestimated in PISA – particularly amongst those who take this test in Welsh.  相似文献   

Identification of histological threshold concepts in health sciences curricula: Students' perception     

Miguel A. Martin-Piedra  Salvador Saavedra-Casado  Antonio Santisteban-Espejo  Fernando Campos  Jesus Chato-Astrain  Oscar Dario Garcia-Garcia  David Sanchez-Porras  Juan de Dios Luna del Castillo  Ismael Angel Rodriguez  Antonio Campos 《Anatomical sciences education》2023,16(1):171-182

Students' metacognitive skills and perceptions are considered important variables for high-quality learning. In this study, students' perceptions were used to identify histological threshold concepts (integrative, irreversible, transformative, and troublesome) in three health sciences curricula. A specific questionnaire was developed and validated to characterize students' perceptions of histological threshold concepts. A sample of 410 undergraduate students enrolled in the dentistry, medicine, and pharmacy degree programs participated in the study. Concepts assessed in the study were clustered to ten categories (factors) by exploratory and confirmatory factor analysis. Concepts linked to tissue organization and tissue functional states received the highest scores from students in all degree programs, suggesting that the process of learning histology requires the integration of both static concepts related to the constituent elements of tissues and dynamic concepts such as stem cells as a tissue renewal substrate, or the euplasic, proplasic and retroplasic states of tissues. The complexity of integrating static and dynamic concepts may pose a challenging barrier to the comprehension of histology. In addition, several differences were detected among the students in different degree programs. Dentistry students more often perceived morphostructural concepts as threshold concepts, whereas medical students highlighted concepts related to two-dimensional microscopic identification. Lastly, pharmacy students identified concepts related to tissue general activity as critical for the comprehension and learning of histology. The identification of threshold concepts through students' perceptions is potentially useful to improve the teaching and learning process in health sciences curricula.  相似文献   

Social correlates of sedentary behavior in young people:The UP&DOWN study     

Veronica Cabanas-Sanchez  Laura Garcia-Cervantes  Laura Esteban-Gonzalo  Maria Jose Girela-Rejon  Jose Castro-Pinero  Oscar L.Veiga 《运动与健康科学(英文)》2020,9(2):189-196

Purpose:The aim of the present study was to analyze the associations of youths' sedentary behavior(SB) with parents' and siblings' SB and physical activity(PA),as well as the associations of youths' coparticipation with parents,siblings,and friends in PA and SB with youths' SB.Methods:The sample consisted of 1543 youths(12.02±2.51 years;788 boys) enrolled in the baseline cohort of the UP&DOWN study.SB was assessed by accelerometry and questionnaire.Participants reported the time spent by their parents and siblings watching television,playing videogames,surfing the Internet,sitting/resting,and doing PA.Further,participants reported coparticipation with parents,siblings,and friends in these activities.Linear mixed models,including school and city as random effects,were performed.Results:Parents' television time was positively associated with youths' screen-based SB.Coparticipation with friends in playing videogames(in boys) and in surfing the Internet(in girls) showed a positive association with screen-based SB and a negative association with educational-based SB.Moreover,coparticipation with siblings and friends in PA was inversely associated with accelerometer-based SB in boys and girls.Conclusion:Our results emphasize the important role of social modeling in the development of sedentary lifestyles in youths.Interventions aimed at reducing health risk behaviors in youths could be more effective if they are oriented from a social perspective that involves their families and networks of their closest friends.  相似文献   

A real-time estimation and control scheme for induction motors based on sliding mode theory     

Oscar Barambones  Patxi Alkorta  Jose Maria Gonzalez de Durana 《Journal of The Franklin Institute》2014

In this paper a sliding mode position control for high-performance real-time applications of induction motors is developed. The design also incorporates a sliding mode rotor flux estimator in order to avoid the flux sensors. The proposed control scheme presents a low computational cost and therefore can be implemented easily in a real-time applications using a low cost Digital Signal Processor (DSP). The stability analysis of the observer and the controller, under parameter uncertainties and load torque disturbances, is provided using the Lyapunov stability theory. Finally simulated and experimental results show that the proposed controller with the proposed observer provides a good trajectory tracking and that this scheme is robust with respect to plant parameter variations and external load disturbances.  相似文献   

A robust vector control for induction motor drives with an adaptive sliding-mode control law     

Oscar Barambones  Patxi Alkorta 《Journal of The Franklin Institute》2011,348(2):300-314

A novel adaptive sliding-mode control system is proposed in order to control the speed of an induction motor drive. This design employs the so-called vector (or field oriented) control theory for the induction motor drives. The sliding-mode control is insensitive to uncertainties and presents an adaptive switching gain to relax the requirement for the bound of these uncertainties. The switching gain is adapted using a simple algorithm which does not imply a high computational load. Stability analysis based on Lyapunov theory is also performed in order to guarantee the closed loop stability. Finally, simulation results show not only that the proposed controller provides high-performance dynamic characteristics, but also that this scheme is robust with respect to plant parameter variations and external load disturbances.  相似文献   

Print Media     

Oscar Ogg  Douglass McMurtrie  John Adamson  Jim Allee Hart  Louis M. Lyons  Michael L. Johnson 《Communication Booknotes Quarterly》2013,44(5):74-76

Oscar Ogg, The 26 Letters (New York: Crowell, 1971—$7.50)

Douglass McMurtrie with the assistance of John Adamson (eds) The Invention of Printing: A Bibliography (New York: Burt Franklin, 1970—price not known)

Jim Allee Hart, Views on the News: The Developing Editorial Syndrome 1500-1800 (Carbondale: Southern Illinois University Press, 1970—$7.95)

Louis M. Lyons, Newspaper Story: One Hundred Years of the Boston Globe (Cambridge: Harvard University Press, 1971—$9.95)

Michael L. Johnson, The New Journalism: The Underground Press, the Artists of Nonfiction, and Changes in the Established Media (Lawrence: University Press of Kansas, 1971—$6.95/2.95)  相似文献   

Real time observer and control scheme for a wind turbine system based on a high order sliding modes     

Oscar Barambones  José A. Cortajarena  Isidro Calvo  José M. Gonzalez de Durana  Patxi Alkorta  Ali Karami-Mollaee 《Journal of The Franklin Institute》2021,358(11):5795-5819

The introduction of advanced control algorithms may improve considerably the efficiency of wind turbine systems. This work proposes a high order sliding mode (HOSM) control scheme based on the super twisting algorithm for regulating the wind turbine speed in order to obtain the maximum power from the wind. A robust aerodynamic torque observer, also based on the super twisting algorithm, is included in the control scheme in order to avoid the use of wind speed sensors. The presented robust control scheme ensures good performance under system uncertainties avoiding the chattering problem, which may appear in traditional sliding mode control schemes. The stability analysis of the proposed HOSM observer is provided by means of the Lyapunov stability theory. Experimental results show that the proposed control scheme, based on HOSM controller and observer, provides good performance and that this scheme is robust with respect to system uncertainties and external disturbances.  相似文献   

High-gain fractional disturbance observer control of uncertain dynamical systems     

Aldo Jonathan Muñoz-Vázquez  Vicente Parra-Vega  Anand Sánchez-Orta  Oscar Martínez-Fuentes 《Journal of The Franklin Institute》2021,358(9):4793-4806

Disturbance observer-based control allows to compensate unknown inputs, however, in most cases, requiring their integer-order differentiability. In this paper, a novel disturbance observer-based state feedback controller is proposed to compensate a more general class of fractional-, but not necessarily integer-order, differentiable unknown inputs. The proposed fractional PI-like structure yields precise conditions for feedback gain tuning. Remarkably, the resulting controller rejects non-differentiable disturbances with a smooth controller, guaranteeing robustness, an outstanding features for tracking tasks, under a prescribed practical stability regimen. A comparison to a fractional sliding mode observer is conducted via simulations to highlight the reliability of the proposed scheme.  相似文献