Interaction between cells in dielectrophoresis and electrorotation experiments     

Miguel Sancho  Genoveva Martínez  Sagrario Mu?oz  José L. Sebastián  Ronald Pethig 《Biomicrofluidics》2010,4(2)

Progress in microelectrode-based technologies has facilitated the development of sophisticated methods for manipulating and separating cells, bacteria, and other bioparticles. For many of these various applications, the theoretical modeling of the electrical response of compartmentalized particles to an external field is important. In this paper we address the analysis of the interaction between cells immersed in rf fields. We use an integral formulation of the problem derived from a consideration of the charge densities induced at the interfaces of the particle compartments. The numerical solution by a boundary element technique allows characterization of their dielectric properties. Experimental validation of this theoretical model is obtained by investigating two effects: (1) The influence that dipolar “pearl chaining” has on the dielectrophoretic behavior of human T lymphocytes and (2) the frequency variation of the spin and orbital torques of approaching insulinoma β-cells in a rotating field.  相似文献   

Non-centralized control for flow-based distribution networks: A game-theoretical insight     

Julian Barreiro-Gomez  Carlos Ocampo-Martinez  Nicanor Quijano  José M. Maestre 《Journal of The Franklin Institute》2017,354(14):5771-5796

This paper solves a data-driven control problem for a flow-based distribution network with two objectives: a resource allocation and a fair distribution of costs. These objectives represent both cooperation and competition directions. It is proposed a solution that combines either a centralized or distributed cooperative game approach using the Shapley value to determine a proper partitioning of the system and a fair communication cost distribution. On the other hand, a decentralized non-cooperative game approach computing the Nash equilibrium is used to achieve the control objective of the resource allocation under a non-complete information topology. Furthermore, an invariant-set property is presented and the closed-loop system stability is analyzed for the non-cooperative game approach. Another contribution regarding the cooperative game approach is an alternative way to compute the Shapley value for the proposed specific characteristic function. Unlike the classical cooperative-games approach, which has a limited application due to the combinatorial explosion issues, the alternative method allows calculating the Shapley value in polynomial time and hence can be applied to large-scale problems.  相似文献   

Faculty attitudes and training needs to respond the new European Higher Education challenges     

María José Fernández Díaz  Rafael Carballo Santaolalla  Arturo Galán González 《Higher Education》2010,60(1):101-118

The main objective of the Bologna Process is to create a “European space” for higher education that allows for comparability, compatibility, and coherence between the existing systems of higher education across Europe. This objective is commonly known as the European higher education area (EHEA). The creation of the EHEA is a new and specific challenge for higher education in Europe, one that depends upon improved faculty development and training across Europe. The integration of Spain and other European countries into European higher education more generally entails these challenges. In order for necessary changes in faculty development and training to take place, university managers and policy makers must account for designing training plans, as well the knowledge, attitudes and needs of faculty members. This investigation was undertaken with these themes in mind. Conducted in Madrid, Spain, it included 257 professors from ten different schools of the Universidad Complutense de Madrid. The aim of the investigation was to understand faculty knowledge and attitudes about changes in higher education in Europe. Moreover, with an eye to helping faculty members cope with the change that is accompanying the creation of EHEA, the investigators sought to understand the importance that faculty members place upon professional development and how current approaches to professional development at the university level could be improved. The results indicate a degree of ignorance regarding changes in European higher education as well as a feeling of resistance on the part of many faculty members. While many faculty members consider knowledge of change processes and adaptability to be important qualities, faculty responses also indicate a clear need for guidance if they are going to integrate new learning models and adequate coping strategies into their work in higher education.  相似文献   

Career coping styles: differences in career attitudes among secondary school students     

Isabel N. Janeiro  José Ferreira Marques 《International Journal for Educational and Vocational Guidance》2010,10(1):35-48

The types of difficulties associated with career attitudes were studied using Super’s model of career maturity (1990) in a group of 620 Portuguese students from grades 9 and 12. A cluster analysis identified four styles with different patterns of association between time perspective, attributional beliefs, self-esteem and career attitudes. The adaptive style showed more committed career attitudes, and the other three styles—superficial, insecure and pessimistic—showed lower levels of career maturity. Implications for career counselling are further discussed.  相似文献   

The relationship between segmental kinematics and ball spin in Type-2 cricket spin bowling     

Aaron J. Beach  René E. D. Ferdinands  Peter J. Sinclair 《Journal of sports sciences》2018,36(10):1127-1134

The techniques of spin bowling in cricket have been largely formulated from the collective intuitions of past players. A standard model of bowling technique has been generally prescribed for both off-spin and leg-spin bowlers, but there has been no biomechanics research to validate this approach. This study measured 20 Type-2 off-spin and 15 Type-2 leg-spin bowlers using a 3D Cortex motion analysis system. Correlation coefficients between segmental kinematic variables and spin rate in the off-spin and leg-spin bowlers revealed that off-spin bowling was associated with an earlier movement time of the thorax, whereas leg-spin bowling was associated with a greater magnitude and earlier movement time of pelvis rotation, as well as a greater magnitude of pelvis-shoulder separation movement. The maximum velocity of rear hip flexion differentiated between both groups of bowlers. The GLM suggested that for off-spinners, rear hip flexion velocity significantly explained the variance in spin rate (subject to sequential timing constraints), while for leg-spinners, the time of maximum rear hip flexion and maximum arm circumduction velocity significantly explained variance in spin rate. This study supports the notion that off-spinners and leg-spinners have significant differences in their joint kinematics, and should not be coached under a one-size-fits-all technical model.  相似文献   

The Victorian College of Pharmacy: a case study of amalgamation failure and success in Australian higher education     

André Brett 《History of education》2018,47(5):644-662

Small specialist higher education institutions often face challenges when negotiating with larger partners. In 1988, John Dawkins, Australia’s federal Minister for Education, introduced sweeping reforms to create a Unified National System of higher education. Dawkins’ criteria for funding necessitated mergers for many smaller providers. The Victorian College of Pharmacy in Melbourne, Victoria, presents a case study of how one institution negotiated this policy and asserted its interests to achieve an optimal outcome. It rejected amalgamation with the University of Melbourne, reaching a superior arrangement with Monash University despite state and federal opposition. This article combines archival research from Melbourne and Monash Universities and the state government with interviews of key players. It examines the importance of institutional identity and how small institutions can navigate government policies of consolidation. It also focuses on the deleterious effects of inflexible government policy and how the College successfully overcame these challenges to complete its desired merger.  相似文献   

Protective effects of photobiomodulation against resistance exercise-induced muscle damage and inflammation in rats     

Helenita Antonia de Oliveira  Ednei Luiz Antonio  Flávio André Silva  Paulo de Tarso Camillo de Carvalho  Regiane Feliciano  Amanda Yoshizaki 《Journal of sports sciences》2018,36(20):2349-2357

We investigated whether low-level laser therapy (LLLT) prior to or post resistance exercise could attenuate muscle damage and inflammation. Female Wistar rats were assigned to non-LLLT or LLLT groups. An 830-nm DMC Laser Photon III was used to irradiate their hind legs with 2J, 4J, and 8J doses. Irradiations were performed prior to or post (4J) resistance exercise bouts. Resistance exercise consisted of four maximum load climbs. The load work during a resistance exercise bout was similar between Control (non-LLLT, 225 ± 10 g), 2J (215 ± 8 g), 4J (210 ± 9 g), and 8J (226 ± 9 g) groups. Prior LLLT did not induce climbing performance improvement, but exposure to 4J irradiation resulted in lower blood lactate levels post-exercise. The 4J dose decreased creatine kinase and lactic dehydrogenase levels post-exercise regardless of the time of application. Moreover, 4-J irradiation exposure significantly attenuated tumor necrosis factor alpha, interleukin-6, interleukin-1β, cytokine-induced neutrophil chemoattractant-1, and monocyte chemoattractant protein-1. There was minor macrophage muscle infiltration in 4J-exposed rats. These data indicate that LLLT prior to or post resistance exercise can reduce muscle damage and inflammation, resulting in muscle recovery improvement. We attempted to determine an ideal LLLT dose for suitable results, wherein 4J irradiation exposure showed a significant protective role.  相似文献   

Effect of 6-weeks WBVT on the behaviour of the lower limb muscle fibres during vertical jumping     

Jacobo Ángel Rubio-Arias  Domingo Jesús Ramos-Campo  Paula Esteban  Fernando Martínez  José Fernando Jiménez 《Journal of sports sciences》2018,36(4):398-406

The purpose of the current study was to examine the effect of 6 weeks of whole body vibration training (WBVT) on body composition, muscle activity of the gastrocnemius and vastus lateralis, gastrocnemius muscle architecture (static and dynamic) and ground reaction forces (performance jump) during the take-off phase of a countermovement jump in young healthy adult males. A total of 33 men (23.31 ± 5.62 years) were randomly assigned to a whole body vibration group (experimental group, EG_WBVT: n = 17; 22.11 ± 4.97 years) or a control group (CG: n = 16; 24.5 ± 6.27 years). The total duration of the intervention phase (WBVT) was 6 weeks with a frequency of 3 sessions per week. Statistically significant differences were observed (P ≤ 0.05) between pre- and post-test in the power peak (Δ 1.91 W · kg^?1; P = 0.001), take-off velocity (0.1 cm · s^?1; P = 0.002) and jump height (Δ 0.4 cm; P = 0.002) for EG_WBVT. There were no statistically significant differences in any of the body composition and muscle architecture variables. Moreover, no significant differences were found between EG_WBVT and CG nor changes in muscle activity during take-off phase of the gastrocnemius and vastus lateralis pre- versus post-training. This study suggests that a 6-week WBVT programme with increasing intensity improves jump performance but does not alter muscle activity nor muscle architecture in healthy young men.  相似文献   

Effect of Dehydration on Passing Decision Making in Soccer Athletes     

Leonardo S. Fortes  José R. A. Nascimento-Júnior  Arnaldo L. Mortatti  Dalton Roberto Alvas Araújo de Lima-Júnior  Maria E. C. Ferreira 《Research quarterly for exercise and sport》2018,89(3):332-339

It seems that dehydration may impair decision-making performance in athletes. Purpose: This study aimed to investigate the influence of dehydration on passing decision-making performance in soccer players. Method: Participants were 40 male soccer players (M_age = 22.3 ± 2.3 years) who agreed to participate in the study and were randomly assigned to the following conditions: control (CON), dehydration (DEH), and euhydration (EUH). The players played in 2 games of 90 min in duration (2 45-min halves) followed by 2 15-min halves (overtime) with and without proper hydration. The Game Performance Assessment Instrument (GPAI) was considered for the analysis of passing decision making. Results: The GPAI analysis indicated effective reduction in the decision-making index in the DEH condition compared with the EUH and CON conditions, F(2, 38) = 31.4, p < .05, ES = 0.8. Conclusions: In conclusion, dehydration may be considered a mediating factor in the passing decision-making performance of male soccer athletes.  相似文献   

Contribution of uncertainty in estimation of active drag using assisted towing method in front crawl swimming     

Pendar Hazrati  Peter James Sinclair  Wayne Spratford  René Edouard Ferdinands  Bruce Robert Mason 《Journal of sports sciences》2018,36(1):7-13

Active drag force in swimming can be calculated from a function of five different variables: swim velocity, tow velocity, belt force, power output and exponent of velocity. The accuracy of the drag force value is dependent on the accuracy of each variable, and on the contribution of each variable to drag estimation. To calculate uncertainty in drag value, first the derivatives of the active drag equation with respect to each variable were obtained. Second, these were multiplied by the uncertainty of that variable. Twelve national age and open level swimmers were recruited to complete four free swimming and five active drag trials. The uncertainties for the free and the tow swim velocities, and for the belt force, contributed approximately 5–6% and 2–3% error, respectively, in calculation of drag. The result of the uncertainty of the velocity exponent (1.8–2.6) indicated a contribution of about 6% error in active drag. The contribution of unequal power output showed that if a power changed 7.5% between conditions, it would lead to about 30% error in calculated drag. Consequently, if a swimmer did not maintain constant power output between conditions, there would be substantial errors in the calculation of active drag.  相似文献