Analysis of self-regulated learning processing using statistical models for count data     

Jeffrey Alan Greene  Lara-Jeane Costa  Kristin Dellinger 《Metacognition and Learning》2011,6(3):275-301

Researchers often use measures of the frequency of self-regulated learning (SRL; Zimmerman, American Educational Research Journal, 45(1), 166–183, 2000) processing as a predictor of learning gains. These frequency data, which are really counts of SRL processing events, are often non-normally distributed, and the accurate analysis of these data requires the use of specialized statistical models. In this study, we demonstrate how to implement and interpret count statistical models in path and latent profile analyses to investigate the role of SRL as a mediator of the relation between pretest and posttest conceptual understanding. Our findings from a sample of 170 college students using a computer to learn about the circulatory system show that SRL does mediate the aforementioned relation, and that count models are a more accurate representation of SRL processing data than standard analysis models based on ordinary least squares estimation. The results of our path analyses revealed which specific SRL processes were related to learning, above and beyond the effect of prior knowledge. Our latent profile analysis revealed two groups of participants, indicative of Brophy’s (2004) model of schematic and aschematic learners. We conclude with implications and future directions for basic and applied SRL research.  相似文献   

Editorial     

Julio Grao  & José-Giné Mora 《European Journal of Education》2000,35(1):1-5

  相似文献   

Secondary immunization inhibits drug induced apoptosis<Emphasis Type="Italic">in vivo</Emphasis>     

Winston Costa Pereira  Muddanna S. Rao  D. M. Vasudevan 《Indian journal of clinical biochemistry : IJCB》2003,18(2):161-168

Immunization with a proper dose of an antigenic stimulus leads to cell proliferation and antibody response of circulating lymphocytes. We have previously observed that Secondary immunized spleenocytes resist ceramide-mediated apoptosisin vitro. Our present study is aimed at investigating thein vivo effect of immunization on apoptosis. Mice were subjected to either Primary or Secondary dose with Tetanus Toxoid. Unimmunized spleenocytes served as controls. Unimmunized, Primary and Secondary immunized mice were later exposed to chemotherapeutic drugs such as Etoposide/Methotrexate/Vincristine to induce apoptosis. Apoptosis was studied by using the Feulgen reaction on 5μ thin parafin sections of spleen. It was observed that Secondary immunized mice showed a lower percentage of apoptosis as compared to Primary or Unimmunized mice that was subjected to either of the chemotherapeutic drugs. It was thus concluded that Secondary immunization inhibits the process of chemotherapeutic drug induced apoptosis in vivo.  相似文献   

Maintenance of responding when reinforcement becomes delayed     

Costa DS  Boakes RA 《Learning & behavior》2007,35(2):95-105

In four experiments with rats, we examined the persistence of behavior when reinforcement was switched from immediate to delayed. In Experiment 1, lever pressing elicited by instrumental training with immediate reinforcement continued when a 20-sec delay of reinforcement was introduced (easy-to-hard condition), whereas when the delay condition was introduced from the start (hard-to-hard condition), responding remained low throughout. A similar result was obtained in Experiment 2, in which lever pressing was elicited by a classical conditioning (autoshaping) procedure. In Experiment 3, rats initially trained with delayed reinforcement continued to respond at a low rate when switched to immediate reinforcement (hard-to-easy condition). By measuring magazine entry (goal tracking) as well as lever pressing (sign tracking) in Experiment 4, we confirmed that such transfer effects at least partly involve the persistence of whatever type of behavior was initially dominant.  相似文献   

Measurement and analysis of soil nitrogen and organic matter content using near-infrared spectroscopy techniques   总被引：2，自引：0，他引：2  

He Y  Song HY  Pereira AG  Gómez AH 《Journal of Zhejiang University. Science. B》2005,6(11):1081-1086

Near infrared reflectance （N1R） spectroscopy is as a rapid, convenient and simple nondestructive technique useful for quantifying several soil properties. This method was used to estimate nitrogen （N） and organic matter （OM） content in a soil of Zhejiang Province, Hangzhou County. A total of 125 soil samples were taken from the field. Ninety-five samples spectra were used during the calibration and cross validation stage. Thirty samples spectra were used to predict N and OM concentration. NIR spectra of these samples were correlated using partial least square regression. The regression coefficients between measured and predicted values of N and OM was 0.92 and 0.93, and SEP （standard error of prediction） were 3.28 and 0.06, respectively, which showed that NIR method had potential to accurately predict these constituents in this soil. The results showed that NIR spectroscopy could be a good tool for precision farming application.  相似文献   

A survey on the light-fastness properties of organic-based Alaska Native artifacts     

Julio M. del Hoyo-Melndez  Marion F. Mecklenburg 《Journal of Cultural Heritage》2010,11(4):48-499

A series of light-fastness tests were conducted on a group of ethnographic objects that will be on exhibit at the Smithsonian Institution Arctic Studies Center, a recent addition to the Anchorage Museum at Rasmuson Center in Alaska. The objects surveyed belong to the collections of the Smithsonian National Museum of Natural History and the Smithsonian National Museum of the American Indian. This work was designed as a feasibility study on the use of a micro-fading tester as a non-contact and non-destructive technique to evaluate the light-stability of materials present in ethnographic collections. A broad range of objects containing a wide variety of materials were selected for the study. The materials investigated included a variety of dyes applied on silk, cotton, and wool substrates along with some unusual materials such as tanned skin and seal gut skin. The results from this investigation have allowed establishing exhibition recommendations taking into consideration the sensitivity of each object, light levels in the museum building, and estimated light exposures based on the duration of the exhibit. The micro-fading tester has proven to be a very useful tool for determining the light-stability of ethnographic materials without causing any harm to the objects. Objects containing equivalent materials are usually classified under a general category based on their probable sensitivity to light. However, micro-fading test results have permitted the detection of dissimilarities among some of these objects, which could be associated to variations in prior fading histories, the quality of raw materials, and different preparation methods.  相似文献   

Optimal sampling frequency in recording of resistance training exercises     

Paolo Bardella  Irene Carrasquilla García  Marco Pozzo  Julio Tous-Fajardo  Eduardo Saez de Villareal 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(1):102-114

The purpose of this study was to analyse the raw lifting speed collected during four different resistance training exercises to assess the optimal sampling frequency. Eight physically active participants performed sets of Squat Jumps, Countermovement Jumps, Squats and Bench Presses at a maximal lifting speed. A linear encoder was used to measure the instantaneous speed at a 200 Hz sampling rate. Subsequently, the power spectrum of the signal was computed by evaluating its Discrete Fourier Transform. The sampling frequency needed to reconstruct the signals with an error of less than 0.1% was f_99.9 = 11.615 ± 2.680 Hz for the exercise exhibiting the largest bandwidth, with the absolute highest individual value being 17.467 Hz. There was no difference between sets in any of the exercises. Using the closest integer sampling frequency value (25 Hz) yielded a reconstruction of the signal up to 99.975 ± 0.025% of its total in the worst case. In conclusion, a sampling rate of 25 Hz or above is more than adequate to record raw speed data and compute power during resistance training exercises, even under the most extreme circumstances during explosive exercises. Higher sampling frequencies provide no increase in the recording precision and may instead have adverse effects on the overall data quality.  相似文献   

Light-load maximal lifting velocity full squat training program improves important physical and skill characteristics in futsal players     

Julio Torres-Torrelo  Juan José González-Badillo 《Journal of sports sciences》2017,35(10):967-975

This study aimed to compare the effect of 6 weeks of resistance training or combined resistance training and change of direction exercises on physical performance and motor skills in futsal players. Thirty-four futsal players were divided into full squat group (SG, n = 12), combined full squat and change of direction exercises group (S+CDG, n = 12) and control group (CG, n = 10). The resistance training for SG consisted of full squat with low load (~45–58% 1RM) and low volume (4–6 repetitions), whereas the S+CDG performed the same resistance training program combined with loaded change of direction. Sprint time in 10 and 20 m, change of direction test, countermovement vertical jump (CMJ) height, maximal strength and force–velocity relationship in full squat exercise, kicking speed ball (BS_mean) and repeated sprint ability (RSA_mean) were selected as testing variables. Both experimental groups showed significant improvements for CMJ, BS_mean and all strength parameters. Only SG resulted in significant sprint gains, whereas S+CDG also achieved significant improvements in RSA_mean. The CG remained unchanged after training period. No significant differences were found between both experimental groups. These findings suggest that only 12 sessions of either lightweight resistance training alone, lifting the load at maximal intended velocity or combined with change of direction exercises is enough to improve several physical and skills capacities critical to futsal performance in adult players.  相似文献   

Kinematic,kinetic and EMG analysis of four front crawl flip turn techniques     

Suzana Matheus Pereira  Caroline Ruschel  Marcel Hubert  Leandro Machado  Helio Roesler  Ricardo Jorge Fernandes 《Journal of sports sciences》2015,33(19):2006-2015

This study aimed to analyse the kinematic, kinetic and electromyographic characteristics of four front crawl flip turn technique variants. The variants distinguished from each other by differences in body position (i.e. dorsal, lateral, ventral) during rolling, wall support, pushing and gliding phases. Seventeen highly trained swimmers (17.9 ± 3.2 years old) participated in interventional sessions and performed three trials of each variant, being monitored with a 3-D video system, a force platform and an electromyography (EMG) system. Studied variables: rolling time and distance, wall support time, push-off time, peak force and horizontal impulse at wall support and push-off, centre of mass horizontal velocity at the end of the push-off, gliding time, centre of mass depth, distance, average and final velocity during gliding, total turn time and electrical activity of Gastrocnemius Medialis, Tibialis Anterior, Biceps Femoris and Vastus Lateralis muscles. Depending on the variant, total turn time ranged from 2.37 ± 0.32 to 2.43 ± 0.33 s, push-off force from 1.86 ± 0.33 to 1.92 ± 0.26 BW and centre of mass velocity during gliding from 1.78 ± 0.21 to 1.94 ± 0.22 m · s^?1. The variants were not distinguishable in terms of kinematical, kinetic and EMG parameters during the rolling, wall support, pushing and gliding phases.  相似文献   

Continuous usage of e-participation: The role of the sense of virtual community     

Mijail Naranjo-Zolotov  Tiago Oliveira  Sven Casteleyn  Zahir Irani 《Government Information Quarterly》2019,36(3):536-545

Local governments around the world are increasingly implementing e-participation platforms to involve citizens in consultation and decision-making processes. E-participation platforms usually succeed and produce positive effects in the community when adopted in the long-term scenario. The adoption of those platforms is still a challenge for local governments. The understanding of the factors that influence the continuous intention to use e-participation over time is critical for the design of diffusion and promotion strategies that motivate the citizens to keep using e-participation. This article explores the drivers that predict the post-adoption of e-participation platforms from the perspective of the sense of virtual community theory, that is the degree of affective attachment to a given community mediated by information technology. Specifically, our research model evaluates the association between the sense of virtual community with use behaviour and the continuous intention to use e-participation. Structural equation modelling was used to evaluate the data collected from 370 citizens who experienced an e-participation platform hosted by a European capital city. We found out that the direct association between the sense of virtual community and use was significant. Even though the direct association between the sense of virtual community and the continuous intention was non-significant, the indirect association sense of virtual community to use to continuous intention was statistically significant. This finding may indicate that the use behaviour is triggered by the influence of other members of the community for a short period of time, but it does not persist to influence the continuous intention over time.  相似文献