Specific tackling situations affect the biomechanical demands experienced by rugby union players     

Elena Seminati  Dario Cazzola  Ezio Preatoni  Grant Trewartha 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(1):58-75

Tackling in Rugby Union is an open skill which can involve high-speed collisions and is the match event associated with the greatest proportion of injuries. This study aimed to analyse the biomechanics of rugby tackling under three conditions: from a stationary position, with dominant and non-dominant shoulder, and moving forward, with dominant shoulder. A specially devised contact simulator, a 50-kg punch bag instrumented with pressure sensors, was translated towards the tackler (n = 15) to evaluate the effect of laterality and tackling approach on the external loads absorbed by the tackler, on head and trunk motion, and on trunk muscle activities. Peak impact force was substantially higher in the stationary dominant (2.84 ± 0.74 kN) than in the stationary non-dominant condition (2.44 ± 0.64 kN), but lower than in the moving condition (3.40 ± 0.86 kN). Muscle activation started on average 300 ms before impact, with higher activation for impact-side trapezius and non-impact-side erector spinae and gluteus maximus muscles. Players’ technique for non-dominant-side tackles was less compliant with current coaching recommendations in terms of cervical motion (more neck flexion and lateral bending in the stationary non-dominant condition) and players could benefit from specific coaching focus on non-dominant-side tackles.  相似文献   

Natural lighting in the Hall of Two Hundred. A proposal for exhibition of its ancient tapestries     

Carla Balocco  Elena Frangioni 《Journal of Cultural Heritage》2010,11(1):113-118

The present paper provides a qualitative and quantitative approach to natural lighting design for the Hall of Two Hundred in Palazzo Vecchio (the present town hall) in Florence. Starting from transient simulation of natural lighting inside the Hall in its present state, using the commercial software Radiance, a design proposal was suggested, detecting the optimal conditions for tapestry conservation and maintenance and taking into account their periodical exhibition, designing a proper wall show-case solution. The suggested design does not modify the architecture and structure of the building. The distribution of natural lighting and consequently of the illuminance and luminance inside the ambient, suggested a solution for exhibition of the historical tapestries, which can guarantee not only tapestry conservation but also the Hall structure and its present uses. The design proposal provides a comfortable lighting environment, rehabilitation and improvement of the historical perception and sight of these works of art, under variable sun and sky conditions throughout the year.  相似文献   

Experiences of Danish Business Expatriates in Russia: Power Distance in Organizational Communication     

Elena V. Chudnovskaya  Laura S. O’Hara 《Journal of Intercultural Communication Research》2016,45(4):261-281

Rapid globalization of business processes stimulates many companies to dispatch their employees – business expatriates – on overseas assignments. Russia differs markedly from many other cultures in terms of specific communication norms and rules. Understanding such differences in organizational life is crucial for the success of business expatriates working there. This study employs in-depth interviews with eight Danish business expatriates who worked in Russia and examines the differences between the Danes and the Russians in terms of communication characteristics related to Hofstede’s cultural dimension power distance. This work enhances scholars’ empirical knowledge of power distance, which has rarely been investigated qualitatively.  相似文献   

The relationships between pelvic range of motion,step width and performance during an athletic sprint start     

Paul Sandamas  Elena M. Gutierrez-Farewik  Anton Arndt 《Journal of sports sciences》2020,38(19):2200-2207

ABSTRACT

The aims of this study were (a) to describe the kinematics underlying the phenomenon of the knee of the swing leg passing medially in front of the athlete during the single push (SP) phase of the block sprint start, and (b) to determine the relationships between block phase pelvis range of motion (RoM), 1^st step width and block phase performance. Three-dimensional kinematic data (250 Hz) were collected from eleven competitive sprinters (100 m PB: 11.17 ± 0.41) performing maximal effort block starts. The joint angles of the rear hip with respect to the pelvis and the pelvis segment angles with respect to the laboratory coordinate system were calculated during the block start phase to the end of the 1^st stance. A combination of pelvis list and rotation (not hip adduction) was coupled with the thigh of the swing leg moving medially during the SP phase. A very high positive correlation was found between pelvic list RoM and 1^st step width (r = 0.799, p = 0.003). No other significant correlations were found. Attempting to reduce pelvic RoM or changing frontal and transverse plane hip joint angles to minimise medial thigh motion is unlikely to lead to an improvement to performance.  相似文献   

Exploring the Relationships between Employee Burnout,Organizational Dissent and Work-family Culture in Russian Organizations     

Cheng Zeng  Tatiana M. Permyakova  Elena A. Smolianina  Irina S. Morozova 《Journal of Intercultural Communication Research》2020,49(2):119-132

ABSTRACT

Employees who fail to balance work and life responsibilities are likely to experience job burnout and, ultimately, withdraw their engagement and voice in the workplace. The current study explored the relationships between employee burnout, work-family balance, and organizational dissent. More importantly, these relationships were tested in an under-researched and culturally unique context, Russia. Data collected from 232 full-time employees in the Perm region were analysed using multiple regression analysis. Analysis revealed that employee burnout is negatively related to articulated dissent and positively related to latent dissent. Furthermore, employees who receive managerial support for prioritizing family issues are less likely to experience job burnout. The influences of national culture and macroeconomic factors on the tested relationships are further discussed  相似文献   

Quality in virtual education environments   总被引：1，自引：0，他引：1  

Elena Barbera 《British journal of educational technology : journal of the Council for Educational Technology》2004,35(1):13-20

The emergence of the Internet has changed the way we teach and learn. This paper provides a general overview of the state of the quality of virtual education environments. First of all, some problems with the quality criteria applied in this field and the need to develop quality seals are presented. Likewise, the dimensions and subdimensions of an empirical instrument to improve and assess the quality of online education are examined. This tool has already been applied to several educational contexts; though not definitive, it aims to improve not only specific areas, but also the whole educational approach as a system.  相似文献   

Engaging Families in Public Libraries     

M. Elena Lopez  Margaret Caspe  Christina Simpson 《Public Library Quarterly》2017,36(4):318-333

Public libraries today are undergoing significant transformations as well as interacting with patrons in new and different ways (Knight Foundation 2017). Part of this transformation is the way libraries are engaging entire families. Libraries are playing a stronger role than ever before in supporting families to promote children’s early literacy and reading skills (Celano and Neuman 2015; Nagle et al. 2016; Neuman and Celano 2010), stimulating adult learning (Boden and Tashijan 2015), creating initiatives to improve family health (Morgan et al. 2016), providing services to families with extreme challenges such as those experiencing poverty, homelessness, food insecurity, and incarceration (Holt and Holt 2010; Terille 2016), as well as becoming spaces for families, especially those who are recent immigrants, to build new relationships and social networks (Khoir et al. 2017; Vårheim 2014). Despite these efforts, few studies have specifically sought to understand the organizational dimensions that support family engagement within a library system and the potential that these efforts have in promoting children’s learning not only in the early years, but also into and throughout middle childhood and adolescence. Based on a yearlong study investigating the power of family engagement in public libraries, this article considers how libraries can begin to adopt a systemic approach to family engagement to further innovate the library space.  相似文献   

Salivary hormones and anxiety in winners and losers of an international judo competition     

Elena Papacosta  George P. Nassis  Michael Gleeson 《Journal of sports sciences》2016,34(13):1281-1287

The purpose of this study was to investigate the responses of salivary hormones and salivary secretory immunoglobulin A (SIgA) and anxiety in winners and losers during an international judo competition. Twenty-three trained, male, national-level judo athletes provided three saliva samples during a competition day: morning, in anticipation of competition after an overnight fast, mid-competition, and post-competition within 15 min post-fight for determination of salivary cortisol, salivary testosterone, salivary testosterone/cortisol ratio, SIgA absolute concentrations, SIgA secretion rate and saliva flow rate. The competitive state anxiety inventory questionnaire was completed by the athletes (n = 12) after the first saliva collection for determination of somatic anxiety, cognitive anxiety and self-confidence. Winners were considered 1-3 ranking place (n = 12) and losers (n = 11) below third place in each weight category. Winners presented higher anticipatory salivary cortisol concentrations (p = 0.03) and a lower mid-competition salivary testosterone/cortisol ratio (p = 0.003) compared with losers with no differences for salivary testosterone. Winners tended to have higher SIgA secretion rates (p = 0.07) and higher saliva flow rates (p = 0.009) at mid-competition. Higher levels of cognitive anxiety (p = 0.02) were observed in the winners, without differences according to the outcome in somatic anxiety and self-confidence. The results suggest that winners experienced higher levels of physiological arousal and better psychological preparedness in the morning, and as the competition progressed, the winners were able to control their stress response better.  相似文献   

Call for papers     

Elena Xeni 《Educational Media International》2013,50(4):353-355

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El papel del análisis gráfico en la resolución de problemas aritméticos     

Elena Botsmanova 《Cultura y Educación》2013,25(3-4):17-21

El planteamiento de los problemas matemáticos adopta tradicionalmente una formulación verbal. Pero dar cuenta con la palabra de los elementos y las relaciones que caracterizan la situación de un problema tiene sus ventajas y sus limitaciones y a veces el niño no alcanza a representarse correctamente los hechos: no alcanza a encontrar los referentes concretos que soportan esas expresiones verbales con cierto grado de abstracción. Se ha sugerido que la ayuda de representación y esquemas gráficos facilita una mejor comprensión del problema que la formulación verbal. En este articulo se presenta una investigación que lo demuestra.  相似文献