Effect of target change during the simple attack in fencing     

Marcos Gutiérrez-Dávila  Matteo Caletti  Raquel Antonio  Enrique Navarro 《Journal of sports sciences》2013,31(10):1100-1107

Abstract

The aim of this study was to test the effect that changing targets during a simple long lunge attack in fencing exerts on the temporal parameters of the reaction response, the execution speed, and the precision and the coordination of the movement pattern. Thirty fencers with more than 10 years of experience participated in this study. Two force platforms were used to record the horizontal components of the reaction forces and thereby to determine the beginning of the movement. A three-dimensional (3D) system recorded the spatial positions of the 9 markers situated on the fencer plus the epee, while a moving target was projected on a screen, enabling the control of the target change. The results indicated that when a target change is provoked the reaction time (RT), movement time (MT), and the time used in the acceleration phase of the centre of mass (CM) increases significantly with respect to the attack executed with a straight thrust. The speed and horizontal distance reached by the CM at the end of the acceleration phase (V_X(CM) and S_X(CM), respectively) significantly decreased, while the errors increased. However, the temporal sequence of the movement pattern did not appreciably change.  相似文献   

Technical Reliability Assessment of the Actigraph GT1M Accelerometer     

Pedro Silva  Jorge Mota  Dale Esliger  Gregory Welk 《Measurement in physical education and exercise science》2013,17(2):79-91

The purpose of this study was to determine the reliability of the Actigraph GT1M (Pensacola, FL, USA) accelerometer activity count and step functions. Fifty GT1M accelerometers were initialized to collect simultaneous acceleration counts and steps data using 15-sec epochs. All reliability testing was completed using a mechanical shaker plate to perform six different test conditions in Experiment 1 and 18 test conditions in Experiment 2. The overall intra- and inter-instrument reliability of the GT1M was CV_intra = 2.9% and CV_inter = 3.5% for counts and CV_intra = 1.1% and CV_inter = 1.2% for steps. No batch effects were evident in the 50 GT1Ms. The Actigraph GT1M accelerometer demonstrated good reliability for measuring both counts and steps. However, the ability of the GT1M to consistently detect acceleration at a given acceleration and frequency condition varied widely. Future studies clarifying the filtering limitations and the threshold necessary to detect the occurrence of movement are warranted.  相似文献   

Two teacher quality measures and the role of context: evidence from Chile     

Maria Veronica Santelices  Edgar Valencia  Jorge Gonzalez  Sandy Taut 《Educational Assessment, Evaluation and Accountability》2017,29(2):111-146

This research examines empirically the relationship between two measures of teacher quality: one based on professional standards and a second one using teacher value-added estimates. It also studies the extent to which teacher observable characteristics, such as teacher training variables, are associated to better performance on either of these measures and whether any of these two assessments is able to effectively measure teacher quality isolated from the effect of the context where teachers work. Context in this article is defined as any variable that is not under the direct control of the teacher but plays an important role on student learning and we believe is captured by school and municipal variables. The study uses hierarchical linear models and information from national and standardized assessments from Chile, specifically from the municipal education sector. Results show a small correlation between the two measures of teacher quality, in the lower end of results from previous studies conducted in the USA, and suggest that there is only a limited relationship between both measures of teacher quality. Teacher initial education type and professional development were statistically associated only to the standard-based measure of teacher quality. Context (both the school and municipal levels) plays an important role in the teacher effect measure, and in the standard-based measures, therefore, we conclude that neither of these measures are context-free. We expect that these results will contribute to the discussion about how to best measure teacher quality and how to evaluate teacher performance both in Chile and other parts of the world.  相似文献   

A Mixed Methods Examination of Gender Disparity in High Schools Implementing Advancement Via Individual Determination (AVID)     

Karen M. Watt  Jeffery Huerta  Jorge Martinez 《Educational Studies A Journal of the American Educational Studies Association》2017,53(4):377-389

This mixed-methods research study offers insights and explanations into gender imbalance in the college readiness program, Advancement Via Individual Determination (AVID). Over 200 schools that have been implementing AVID for more than 4 years across the United States participated in this study. Three years of archived historical data pertaining to school demographic information and AVID certification information was accessed and analyzed to examine recruitment and retention of male and female students over time, as well as student enrollment in rigorous curriculum. Our research indicated that at the high school level, gender disparity became most apparent in the 11th and 12th grades. Results indicated that schools that struggled to recruit and retain boys continued to enroll AVID students, both boys and girls, into rigorous advanced placement curriculum at comparable rates as schools that did not struggle to recruit and retain boys in the program. This indicates that once in AVID, boys and girls are provided equal access to rigor; however, recruiting and retaining boys in AVID continues to be a challenge for AVID schools. Research participants indicated that academic identity, peer and family support, leadership and mentoring opportunities and male role models influence male participation in AVID.  相似文献   

Biology Undergraduates' Misconceptions about Genetic Drift     

TM Andrews  RM Price  LS Mead  TL McElhinny  A Thanukos  KE Perez  CF Herreid  DR Terry  PP Lemons 《CBE life sciences education》2012,11(3):248-259

This study explores biology undergraduates' misconceptions about genetic drift. We use qualitative and quantitative methods to describe students' definitions, identify common misconceptions, and examine differences before and after instruction on genetic drift. We identify and describe five overarching categories that include 16 distinct misconceptions about genetic drift. The accuracy of students' conceptions ranges considerably, from responses indicating only superficial, if any, knowledge of any aspect of evolution to responses indicating knowledge of genetic drift but confusion about the nuances of genetic drift. After instruction, a significantly greater number of responses indicate some knowledge of genetic drift (p = 0.005), but 74.6% of responses still contain at least one misconception. We conclude by presenting a framework that organizes how students' conceptions of genetic drift change with instruction. We also articulate three hypotheses regarding undergraduates' conceptions of evolution in general and genetic drift in particular. We propose that: 1) students begin with undeveloped conceptions of evolution that do not recognize different mechanisms of change; 2) students develop more complex, but still inaccurate, conceptual frameworks that reflect experience with vocabulary but still lack deep understanding; and 3) some new misconceptions about genetic drift emerge as students comprehend more about evolution.  相似文献   

Multimodal indexing based on semantic cohesion for image retrieval     

Hugo Jair Escalante  Manuel Montes  Enrique Sucar 《Information Retrieval》2012,15(1):1-32

  相似文献   

Enhancing preschool children's vocabulary: Effects of teacher talk before,during and after shared reading     

Jorge E. Gonzalez  Sharolyn Pollard-Durodola  Deborah C. Simmons  Aaron B. Taylor  Matthew J. Davis  Melissa Fogarty  Leslie Simmons 《Early childhood research quarterly》2014

This observational study analyzed patterns of teacher extratextual talk as it occurs before, during, and after reading books to children, and the frequency and duration of teacher questioning by type (label, define, associate) on preschoolers’ receptive and expressive vocabulary knowledge. Over the course of 18 weeks, 13 teachers and 100 children participated in ninety 20-min small-group sessions of teacher-guided shared reading instruction. Teachers’ reading instruction was examined through videotaped observations using the Multi-Option Observation System for Experimental Studies (MOOSES™; Tapp, Wehby, & Ellis, 1995). Two findings, in particular, yielded relevant educational and theoretical implications. First, time spent after reading was significantly related to expressive vocabulary. However, question timing did not seem to matter in terms of receptive vocabulary outcomes. Second, duration of teacher association questioning was significantly related to receptive vocabulary outcomes while both frequency and duration of teacher vocabulary-related association-level questioning were related to expressive vocabulary. For receptive vocabulary, both vocabulary- and comprehension-related association-level questioning mattered. These findings complement the body of work demonstrating that engaging children in interactive shared reading that elicits their active participation is related to meaningful gains in children's language and literacy growth. Limitations of the study and directions for future research are discussed.  相似文献   

Obturated vs. Obturator: What obturates what?     

Jorge M. Barcia B.Sc.  Ph.D.  Francisco J. Romero M.D.  Ph.D. 《Anatomical sciences education》2013,6(5):359-360

  相似文献   

Impact of Media     

Dennis K. Davis  Stanley J. Baran  James B. LOmert  Emile McAnany  Jorge Schnitman  Noreene Janus 《Communication Booknotes Quarterly》2013,44(3)

Dennis K. Davis and Stanley J. Baran, Mass Communication and Everyday Life: A Perspective on Theory and Effects (Belmont, Ca.: Wadsworth Publishing, 1981—$7.95, paper)

James B.LOmert Does Mass Communication Change Public Opinion After All? A New Approach to Effects Analysis (Chicago: Nelson-Hall Publishers, 1981—$17.95/8.95)

Annual Report 1978/79. 1979/80 of the John and Mary R. Markle Foundation (50 Rockefeller Plaza, New York, N.Y. 10020—free on request, paper)

Emile McAnany, Jorge Schnitman, and Noreene Janus, eds. Communication and Social Structure: Critical Studies in Mass Media Research (New York: Praeger Special Studies, 1981—price not known)  相似文献   

The community model of content management: A case study of the music industry     

Enrique Dans 《媒体管理杂志》2013,15(1):4-13

Abstract

In 450 years of existence, the written press has never faced a change with the intensity and consequences as those of the Internet. The decision of going online represents a whole set of opportunities and threats that publishers must carefully weigh. Once they have made the step, newspapers find themselves in a completely different competitive environment. They deal with different competitors, business models, customers and patterns of consumption. The present study explores such patterns of consumption by using data from 15 Spanish newspapers, covering time periods from 2 to 20 months. Characteristics of the printed newspapers and general patterns of the Internet are also analyzed in order to isolate the factors that enable an Internet newspaper to achieve a high level of readership. The findings indicate that reading patterns on the Internet strongly differ from those in the physical world, particularly when we consider weekday versus weekend circulation. The use of the newspaper is different too: reading of Internet newspapers is usually more functional and goal oriented, as indicated by the small number of pages read per visit. These and other results can provide publishers with valuable insights to understand this new frontier in the history of journalism.  相似文献