Clones identification of Sequoia sempervirens (D. Don) Endl. in Chile by using PCR-RAPDs technique     

Manuel Toral Ibañez  Margarita Caru  Miguel A. Herrera  Luis Gonzalez  Luis M. Martin  Jorge Miranda  Rafael M. Navarro-Cerrillo 《Journal of Zhejiang University. Science. B》2009,10(2):112-119

A protocol of polymerase chain reaction-random amplified polymorphic DNAs (PCR-RAPDs) was established to analyse the gene diversity and genotype identification for clones of Sequoia sempervirens (D. Don) Endl. in Chile. Ten (out of 34) clones from introduction trial located in Voipir-Villarrica, Chile, were studied. The PCR-RAPDs technique and a modified hexadecyltrimethylammonium bromide (CTAB) protocol were used for genomic DNA extraction. The PCR tests were carried out employing 10-mer random primers. The amplification products were detected by electrophoresis in agarose gels. Forty nine polymorphic bands were obtained with the selected primers (BG04, BF07, BF12, BF13, and BF14) and were ordered according to their molecular size. The genetic similarity between samples was calculated by the Jaccard index and a dendrogram was constructed using a cluster analysis of unweighted pair group method using arithmetic averages (UPGMA). Of the primers tested, 5 (out of 60) RAPD primers were selected for their reproducibility and high polymorphism. A total of 49 polymorphic RAPD bands were detected out of 252 bands. The genetic similarity analysis demonstrates an extensive genetic variability between the tested clones and the dendrogram depicts the genetic relationships among the clones, suggesting a geographic relationship. The results indicate that the RAPD markers permitted the identification of the assayed clones, although they are derived from the same geographic origin. Project (No. CONICYT-FONDEF PROYECT D01 I 1008) supported by the National Commission of Science and Research of Chile  相似文献   

Jump higher,run faster: effects of diversified sport participation on talent identification and selection in youth basketball     

Jorge Arede  Pedro Esteves  António Paulo Ferreira  Jaime Sampaio  Nuno Leite 《Journal of sports sciences》2013,31(19):2220-2227

ABSTRACT

The aims of this study were to examine the medium-term effects of previous experiences during early stages of sport development on physical capacities of under-13 (U-13) talented basketball players and, to identify variables that discriminated under-14 (U-14) national team training camp selection. Anthropometrical and physical measurements were collected during a basketball training camp. Previous sport experiences (6–10 years), maturity offset, power outputs for jumping and sprinting were determined. A cluster analysis was used to allocate the subjects according to their different levels of sport experiences (more specialized vs. less specialized) to allow creating a dummy variable for the subsequent analysis of the physical variables. A stepwise discriminant analysis was computed to identify the construct that best classifies selected and non-selected players for U-14 national team training camp. The less specialized group outscored more specialized in all physical parameters, irrespectively of gender. The Abalakov Jump Peak Power and Predicted Adult Height (PAH) could successfully discriminate selected from non-selected players for U-14 national team training camp in boys and PAHin girls. The diversified and non-specific sport stimulus during early ages seem to be determinant to the acquisition and development of fundamental movement skills of talented basketball players.  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   

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

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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   

Statistical Models and Inference for the True Equating Transformation in the Context of Local Equating     

Jorge González B.  Matthias von Davier 《Journal of Educational Measurement》2013,50(3):315-320

Based on Lord's criterion of equity of equating, van der Linden (this issue) revisits the so‐called local equating method and offers alternative as well as new thoughts on several topics including the types of transformations, symmetry, reliability, and population invariance appropriate for equating. A remarkable aspect is to define equating as a standard statistical inference problem in which the true equating transformation is the parameter of interest that has to be estimated and assessed as any standard evaluation of an estimator of an unknown parameter in statistics. We believe that putting equating methods in a general statistical model framework would be an interesting and useful next step in the area. van der Linden's conceptual article on equating is certainly an important contribution to this task.  相似文献   

A scale-based approach to interdisciplinary research and expertise in sports     

Jorge Ibáñez-Gijón  Martinus Buekers  Antoine Morice  Guillaume Rao  Nicolas Mascret  Jérome Laurin 《Journal of sports sciences》2017,35(3):290-301

After more than 20 years since the introduction of ecological and dynamical approaches in sports research, their promising opportunity for interdisciplinary research has not been fulfilled yet. The complexity of the research process and the theoretical and empirical difficulties associated with an integrated ecological-dynamical approach have been the major factors hindering the generalisation of interdisciplinary projects in sports sciences. To facilitate this generalisation, we integrate the major concepts from the ecological and dynamical approaches to study behaviour as a multi-scale process. Our integration gravitates around the distinction between functional (ecological) and execution (organic) scales, and their reciprocal intra- and inter-scale constraints. We propose an (epistemological) scale-based definition of constraints that accounts for the concept of synergies as emergent coordinative structures. To illustrate how we can operationalise the notion of multi-scale synergies we use an interdisciplinary model of locomotor pointing. To conclude, we show the value of this approach for interdisciplinary research in sport sciences, as we discuss two examples of task-specific dimensionality reduction techniques in the context of an ongoing project that aims to unveil the determinants of expertise in basketball free throw shooting. These techniques provide relevant empirical evidence to help bootstrap the challenging modelling efforts required in sport sciences.  相似文献