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   

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   

The upper Schuylkill river     

Oscar C.S. Carter 《Journal of The Franklin Institute》1897,144(5):366-379

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A multivariate approach; evaluating major objectives in science education     

Ashley G. Morgan  Oscar J. Brouillette 《科学教学研究杂志》1969,6(2):163-165

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Book reviews     

Thomas F. Baldwin  Oscar H. Gandy Jr. 《Journal of Media Economics》2013,26(3):59-63

Ken Auletta, Three Blind Mice (New York: Random House, 1991) 642 pp.

Marc Raboy. Missed Opportunities: The Story of Canada's Broadcasting Policy (Montreal: McGill‐Queen's University Press, 1990) 471 pp.  相似文献