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991.
In this review all empirically based articles published in the years 1997 and 1998 in five acclaimed journals in the field of research of high ability and talent will be compared. For this purpose several questions will be taken into consideration, including the problems of the identification procedures used, the predominating research questions and the quality of the methodological standards. The results show that it is difficult to compare the studies due to the various procedures used to identify giftedness. In contrast, regarding the thematic orientation of the research studies themselves, the existence of a virulent problem in gifted research could be confirmed. The methodological standards adhered to in the studies give rise to troubling thoughts, possibly the most worrisome outcome being that the integration of a control group occurred in less than one-quarter of the studies. A definitive result of the study is the confirmation that gifted research is conducted within the framework of a fragmented research community where studies are performed under various methodological viewpoints, which are often unsatisfactory. The appearance of approximately one new publication per day is accompanied by the dangers of a metamorphosis of quality into pure quantity and the loss of any sort of conceptual overview. The aim of this article is, therefore, to determine whether these suspicions can be substantiated specifically regarding theoretical and methodological aspects of empirical studies in giftedness research. 相似文献
992.
In a simultaneous discrimination involving a positive (S+) and a negative (S−) stimulus, positive value appears to transfer from the S+ to the S−. However, negative value does not appear to transfer from the S− to the S+. Instead, when sufficient experience with the contingencies associated with responding to the S− is provided, it appears that the presence of the S− enhances the value of the S+ (i.e., a contrast effect is found). The purpose of the present experiments was to further examine the influence of the S+ on the S− in a simultaneous discrimination (between subjects in Experiment 1 and within subjects in Experiment 2). In both experiments, we found that under typical training conditions, given little direct experience with the value of the S−, value transfers from the S+ to the S−. If sufficient experience with the value of the S− is provided, however, contrast between the S+ and the S− can be demonstrated. Thus, in a simultaneous discrimination, value transfer from the S+ to the S− depends on the animal’s having responded relatively little to the S−. 相似文献
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Sridevi Kurella Monika Manocha Leenu Sabhnani Beena Thomas D. N. Rao 《Indian journal of clinical biochemistry : IJCB》2000,15(1):83-100
The dramatic advancements in the field of vaccinology has led to the formulation of chemically well defined vaccines composed of synthetic peptides and recombinant proteins derived from the immunologically dominant regions of the pathogens. Though these subunit vaccines are safer compared to the traditional vaccines they are known to be poorly immunogenic. This necessitates the use of adjuvants to enhance the immunogenicity of these vaccine formulations. The most common adjuvant for human use is alum. Research in the past has focused on the development of systemic immunity using conventional immunization protocols. In the present are, the emphasis is on the development and formulation of alternative adjuvants and delivery systems in generating systemic as well as mucosal immunity. This review mainly focuses on a variety of adjuvants (particulate as well as non-particulate) used with protective antigens of HIV, malaria, plague, leprosy using modified delivery vehicles. The experience of our laboratory and other researchers in this field clearly proves that these new age adjuvants and delivery systems undoubtedly generate enhanced immune response-both humoral and cell mediated. The choice of antigens, the nature of adjuvant used and the mode of delivery employed have a profound effect on the type of immune response generated. Besides the quantity, the quality of the antibodies generated also play a vital role in protection against these diseases. Some of the adjuvants and delivery systems used promoted high titre and affinity antibodies, which were shown to be cytophilic in nature, an important criteria in providing protection to the host. Thus the studies on these adjuvants/delivery systems with respect to various infectious diseases indicate their active role in efficient modulation of immune response along with safety and permissibility. 相似文献
998.
The relationship between peak height velocity and physical performance in youth soccer players 总被引:1,自引:1,他引:0
Philippaerts RM Vaeyens R Janssens M Van Renterghem B Matthys D Craen R Bourgois J Vrijens J Beunen G Malina RM 《Journal of sports sciences》2006,24(3):221-230
Longitudinal changes in height, weight and physical performance were studied in 33 Flemish male youth soccer players from the Ghent Youth Soccer Project. The players' ages at the start of the study ranged from 10.4 to 13.7 years, with a mean age of 12.2 +/- 0.7 years. Longitudinal changes were studied over a 5 year period. Peak height velocity and peak weight velocity were determined using non-smoothed polynomials. The estimations of peak height velocity, peak weight velocity and age at peak height velocity were 9.7 +/- 1.5 cm x year-1, 8.4 +/- 3.0 kg x year-1 and 13.8 +/- 0.8 years, respectively. Peak weight velocity occurred, on average, at the same age as peak height velocity. Balance, speed of limb movement, trunk strength, upper-body muscular endurance, explosive strength, running speed and agility, cardiorespiratory endurance and anaerobic capacity showed peak development at peak height velocity. A plateau in the velocity curves was observed after peak height velocity for upper-body muscular endurance, explosive strength and running speed. Flexibility exhibited peak development during the tear after peak height velocity. Trainers and coaches should be aware of the individual characteristics of the adolescent growth spurt and the training load should also be individualized at this time. 相似文献
999.
The purpose of this study was to assess the power output of field-based downhill mountain biking. Seventeen trained male downhill cyclists (age 27.1 +/- 5.1 years) competing nationally performed two timed runs of a measured downhill course. An SRM powermeter was used to simultaneously record power, cadence, and speed. Values were sampled at 1-s intervals. Heart rates were recorded at 5-s intervals using a Polar S710 heart rate monitor. Peak and mean power output were 834 +/- 129 W and 75 +/- 26 W respectively. Mean power accounted for only 9% of peak values. Paradoxically, mean heart rate was 168 +/- 9 beats x min(-1) (89% of age-predicted maximum heart rate). Mean cadence (27 +/- 5 rev x min(-1)) was significantly related to speed (r = 0.51; P < 0.01). Analysis revealed an average of 38 pedal actions per run, with average pedalling periods of 5 s. Power and cadence were not significantly related to run time or any other variable. Our results support the intermittent nature of downhill mountain biking. The poor relationships between power and run time and between cadence and run time suggest they are not essential pre-requisites to downhill mountain biking performance and indicate the importance of riding dynamics to overall performance. 相似文献
1000.
Linguistic influences on networks of professional communication and recognition among engineers at two Quebec universities were examined. It was hypothesized that chemists and engineers affiliated with the French medium University of Montreal and the Ecole Polytechnique would be less active in research and more likely to obtain scientific recognition locally and to feel professionally unrecognized outside Quebec compared to their colleagues at McGill University. The findings suggest that the localizing effects of using a medium of scientific training which is not the predominant language of international scientific communication and recognition (French) are ambiguous. Although chemists and engineers at the French medium institutions were less active researchers, their language of professional communication with other scientific communities was English and there was little sense of isolation.This research has been supported by grants from the Canadian Council and the Ecole Polytechnique of Montreal. The authors also wish to thank Miss Madeleine Palmer, Miss Daniella Quiniou and Miss Rosalba Casas for their help in data collection for this paper. 相似文献