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401.
Carlos Torres-Fuchslocher 《Research Policy》2010,39(2):268-277
The development of local technology-intensive suppliers (t-suppliers) may contribute to both reinforcing the industrial base and supporting the competitiveness of primary production in developing countries. This article explores the role of t-suppliers in natural resource-based economies and outlines a theoretical framework for the analysis of the factors which foster or constrain their development and defines areas for an effective promotion. The proposed model of analysis distinguishes between factors influencing the development of t-suppliers on the level of the main industry, the level of supplier firms or firm-level and the level of external determinants with special reference to industrial policy factors. 相似文献
402.
Joanne Klevens José William Martínez Brenda Le Carlos Rojas Adriana Duque Rafael Tovar 《International Journal of Educational Research》2009,48(5):307-319
We conducted a three-arm cluster randomized controlled trial (n = 2491) to evaluate a teacher delivered intervention to reduce aggressive and antisocial behavior and increase prosocial behavior in the classroom. A second aim of this trial was to establish whether combining this intervention with an intervention for parents was better than the teacher-only intervention. This evaluation was conducted in a resource-poor setting (Pereira, Colombia). The findings show that both interventions prevented increases in aggressive and antisocial behavior. However, the teacher-only intervention also had a positive impact on increasing prosocial behavior. 相似文献
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The first part of this article explores whether convergence has occurred in technology and income across EU regions during the period 1990-2002. The second part evaluates whether these two processes of convergence are related to each other. With respect to the first question, we find that all R&D indicators and patents have converged among regions during the 1990s and this has ran parallel to a real convergence in income per capita levels. Regarding the second question, we have identified a strong relationship between the distribution of technology indicators and the distribution of regional income in Europe. Our main result is that convergence in business R&D leads to convergence in patents, which in turn leads to convergence in income per capita. Although, we identify a role for government R&D and higher education spending in this process, the policy implications for these two variables are less clear. 相似文献
406.
Jesús Navarro-Moreno Rosa María Fernández-Alcalá José Domingo Jiménez-López Juan Carlos Ruiz-Molina 《Journal of The Franklin Institute》2019,356(5):3115-3138
The optimal widely linear state estimation problem for quaternion systems with multiple sensors and mixed uncertainties in the observations is solved in a unified framework. For that, we devise a unified model to describe the mixed uncertainties of sensor delays, packet dropouts and uncertain observations by using three Bernoulli distributed quaternion random processes. The proposed model is valid for linear discrete-time quaternion stochastic systems measured by multiple sensors and it allows us to provide filtering, prediction and smoothing algorithms for estimating the quaternion state through a widely linear processing. Simulation results are employed to show the superior performance of such algorithms in comparison to standard widely linear methods when mixed uncertainties are present in the observations. 相似文献
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Alejandro Bastida Castillo Carlos D. Gómez Carmona Ernesto De la cruz sánchez José Pino Ortega 《European Journal of Sport Science》2018,18(4):450-457
There is interest in the accuracy and inter-unit reliability of position-tracking systems to monitor players. Research into this technology, although relatively recent, has grown exponentially in the last years, and it is difficult to find professional team sport that does not use Global Positioning System (GPS) technology at least. The aim of this study is to know the accuracy of both GPS-based and Ultra Wide Band (UWB)-based systems on a soccer field and their inter- and intra-unit reliability. A secondary aim is to compare them for practical applications in sport science. Following institutional ethical approval and familiarization, 10 healthy and well-trained former soccer players (20?±?1.6 years, 1.76?±?0.08?cm, and 69.5?±?9.8?kg) performed three course tests: (i) linear course, (ii) circular course, and (iii) a zig–zag course, all using UWB and GPS technologies. The average speed and distance covered were compared with timing gates and the real distance as references. The UWB technology showed better accuracy (bias: 0.57–5.85%), test–retest reliability (%TEM: 1.19), and inter-unit reliability (bias: 0.18) in determining distance covered than the GPS technology (bias: 0.69–6.05%; %TEM: 1.47; bias: 0.25) overall. Also, UWB showed better results (bias: 0.09; ICC: 0.979; bias: 0.01) for mean velocity measurement than GPS (bias: 0.18; ICC: 0.951; bias: 0.03). 相似文献
410.
Mota J Silva P Santos MP Ribeiro JC Oliveira J Duarte JA 《Journal of sports sciences》2005,23(3):269-275
The aims of this study were: (1) to observe participation in moderate-to-vigorous physical activity (MVPA) during school recess periods; (2) to determine the relative importance of physical activity during recesses to overall daily physical activity; and (3) to examine differences in physical activity between the sexes during unstructured recess periods. The participants were 22 school children (10 boys, 12 girls) aged 8 - 10 years (mean = 8.9, s = 0.7) in the third and fourth grades. Daily totals for the physical activity variables were calculated by summing the values for each hour of 14 h of physical activity measurements (08:00 to 22:00 h). Recess times (minutes) were as follows: morning 10:30 to 11:00 h and afternoon 15:30 to 16:00 h. We did not differences between boys and girls in daily total accelerometer counts or the overall time spent in MVPA. However, girls were significantly (P < 0.05) more involved (38%) in MVPA during recess time than boys (31%). Participation in MVPA during recess contributes significantly more (P < 0.05) for girls (19%) than boys (15%) to the total amount of physical activity suggested by international health-related physical activity guidelines, while the percentage of time engaged in MVPA during recess time at school accounts for a small amount of the daily MVPA (6% for boys and 8% for girls). The results of this study suggest that school recess time is an important setting to promote MVPA and contributes to daily physical activity in young children, especially in girls. 相似文献