A person-centered approach to achievement goal orientations in competitive tennis players: Associations with motivation and mental toughness     

Richard Gregory Cowden  Nicolas Mascret  Timothy Ryan Duckett 《运动与健康科学(英文)》2021,10(1):73

BackgroundResearch on achievement goal orientations in sport has typically relied on the use of variable-centered approaches that tend to overlook population heterogeneity. In this study, we used a person-centered approach to identify subgroups of competitive tennis players according to unique combinations of achievement goal orientations and tested for subgroup differences in motivation and mental toughness.MethodsA sample of 323 competitive tennis athletes (69.35% male) between 15 and 25 years of age (17.60 ± 2.40 years, mean ± SD) completed the 3 × 2 Achievement Goal Questionnaire for Sport, Sport Motivation Scale II, and Mental Toughness Index. Latent profile analysis was used to identify unique combinations of achievement goal orientations. Comparisons between latent subgroups on autonomous motivation, controlled motivation, and mental toughness were performed using analysis of variance.ResultsLatent profile analysis supported 3 distinct patterns of achievement goal profiles that were primarily distinguishable based on valence of competence (i.e., approach vs. avoidance). Analyses of variance indicated that athletes who were classified into subgroups that endorsed approach types of goals (regardless of the types of avoidance goals they endorsed) reported higher levels of autonomous motivation and mental toughness.ConclusionResults indicated that athletes tend to pursue a number of achievement goals collectively rather than in isolation. Although approach goals are more commonly linked to adaptive psychological functioning and positive outcomes, avoidance goals may also be associated with desirable psychological characteristics if they are pursued in conjunction with approach types of achievement goals.  相似文献   

Development of a chemically defined medium for Planctopirus limnophila to increase biomass production     

《Electronic Journal of Biotechnology》2021

BackgroundPlanctomycetes is a phylum of biofilm-forming bacteria with numerous biosynthetic gene clusters, offering a promising source of new bioactive secondary metabolites. However, the current generation of chemically defined media achieves only low biomass yields, hindering research on these species. We therefore developed a chemically defined medium for the model organism Planctopirus limnophila to increase biomass production.ResultsWe found that P. limnophila grows best with a 10 mM sodium phosphate buffer. The replacement of complex nitrogen sources with defined amino acid solutions did not inhibit growth. Screening for vitamin requirements revealed that only cyanocobalamin (B12) is needed for growth. We used response surface methodology to optimize the medium, resulting in concentrations of 10 g/L glucose, 34 mL/L Hutner’s basal salts, 23.18 mM KNO₃, 2.318 mM NH₄Cl and 0.02 mg/L cyanocobalamin. The analysis of amino acid consumption allowed us to develop a customized amino acid solution lacking six of the amino acids present in Aminoplasmal 10%. Fed-batch cultivation in a bioreactor using the optimized medium achieved a final ΔOD₆₀₀ of 46.8 ± 0.5 after 108 h, corresponding to a cell dry weight of 13.6 ± 0.7 g/L.ConclusionsThe optimized chemically defined medium allowed us to produce larger amounts of biomass more quickly than reported in earlier studies. Further research should focus on triggering P. limnophila biofilm formation to activate the gene clusters responsible for secondary metabolism.How to cite: Kruppa OC, Gerlach D, Fan R, et al. Development of a chemically defined medium for Planctopirus limnophila to increase biomass production. Electron J Biotechnol 2021;54. https://doi.org/10.1016/j.ejbt.2021.09.002.  相似文献   

国外体育创新创业研究的前沿热点与发展启示——基于Web Of Science的文献计量分析     

唐元超  许建  蒋东升  陈政天 《浙江体育科学》2020,(3):8-14,108

为更好地了解国外体育创新创业领域研究的前沿热点和发展趋势,明晰我国发展的不足。运用文献计量法、数理统计法等对1968—2018年Web Of Science(SSCI、SCI等核心库)中的收录的123篇文献进行了计量分析。结果表明:国外体育创新创业领域已取得一定的成果,但也仍存在作者合作脉络单一、实证研究单薄、案例分析不够全面等问题,建议国内应取长补短,从巩固理论研究、深入实证研究、加强协作脉络、延伸企业家精神内涵等方面入手,以期更好地促进我国体育创新创业领域的发展。  相似文献   

Study Abroad Experience and Career Decision-Making: A Qualitative Study of Chinese Students     

WU Yihan 《Frontiers of Education in China》2020,15(2):313

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Can a non-Muslim Mass Shooter be a “Terrorist”?: A Comparative Content Analysis of the Las Vegas and Orlando Shootings     

Mohamad Hamas Elmasry  Mohammed el-Nawawy 《Journalism Practice》2020,14(7):863-879

ABSTRACT

This study used the 2017 Las Vegas and 2016 Orlando mass shootings as case studies to explore alleged double standards in reporting of events featuring Muslim and non-Muslim mass perpetrators of violence. The study used framing theory and content analysis to examine Los Angeles Times and New York Times coverage of the shootings during the one week immediately following each event. Findings are consistent with previous literature and the researchers’ expectations. The Orlando shooting, carried out by a Muslim, was allotted more coverage despite the fact that it produced nine fewer fatalities than the Las Vegas shooting, perpetrated by a white non-Muslim. The analysis also showed that the examined newspapers were more likely to employ a “terrorism” frame in their coverage of the Orlando shooting than in their coverage of the Las Vegas shooting; link the Orlando mass shooting with the global war on terrorism; and to humanize Stephen Paddock, the white perpetrator of the Las Vegas shooting. Framing differences found in this study may contribute to downplaying the threat of white male gun violence, and to reinforcing fears of Islam and Muslims.  相似文献   

The application of inertial measurement units and functional principal component analysis to evaluate movement in the forward 3½ pike somersault springboard dive     

Cherie Walker  John Warmenhoven  Peter J. Sinclair 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(2):146-162

Based on technological and analytical advances, the capability to more accurately and finitely examine biomechanical and skill characteristics of movement has improved. The purpose of this study was to use Inertial Measurement Units (IMUs) and Functional Principal Components Analysis (fPCA) to examine the role of movement variability (assessed via angular velocity), on 2 divers (1 international level; 1 national) performing the forward 3½ pike somersault dive. Analysis of angular velocity curves during ive-flight identified 5 fPCs, accounting for 96.5% of movement variability. The national diver’s scatter plots and standard deviation of fPC scores illustrated larger magnitudes of angular velocity variability across dive flight. For fPC1 and fPC3, magnitudes of SD variability were 282.6 and 201.5, respectively. The international diver illustrated more consistent angular velocity profiles, with clustering of fPCs scores (e.g., fPC1 & 3 = SD’s of 75.2 & 68.0). To account for lower variability in the international diver, the ability to better coordinate movement sequences and functionally utilise feedback in response to initiation of the somersault position is highlighted. Overall, findings highlight how both IMUs and fPCA can more holistically and finitely examine the biomechanical and skill characteristics of movement sequences with the capability to inform athlete development.  相似文献   

基于用户兴趣度量的知识发现服务精准推荐     

丁梦晓  毕强  许鹏程  李洁  牟冬梅 《图书情报工作》2019,63(3):21-29

[目的/意义]针对当前知识发现服务中存在的个性化程度不高和推荐效果不佳等问题，提出一种基于用户兴趣度量和内容分析的推荐算法。[方法/过程]文章通过特征词分布、LDA主题分布、引文结构网络三个维度构建学术资源模型，并通过对用户行为的度量，计算用户对其浏览学术资源的兴趣度，结合学术资源模型构建用户兴趣模型。将用户兴趣模型与学术资源模型匹配，计算其相似度，得到用户对每条学术资源的兴趣值，最后将兴趣值最高的TOP-N学术资源推荐给用户。[结果/结论]通过实验检验算法的有效性和推荐准确率，结果显示，本文从实时动态度量兴趣的角度，提出的推荐算法能较好地预测用户兴趣，推荐效果显著，为实现发现服务精准推荐提供思路。  相似文献   

The influence of water depth on kinematic and spatiotemporal gait parameters during aquatic treadmill walking     

Taeyou Jung  Yumi Kim  Hyosok Lim  Konstantinos Vrongistinos 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(3):297-307

The purpose of this study was to investigate kinematic and spatiotemporal variables of aquatic treadmill walking at three different water depths. A total of 15 healthy individuals completed three two-minute walking trials at three different water depths. The aquatic treadmill walking was conducted at waist-depth, chest-depth and neck-depth, while a customised 3-D underwater motion analysis system captured their walking. Each participant’s self-selected walking speed at the waist level was used as a reference speed, which was applied to the remaining two test conditions. A repeated measures ANOVA showed statistically significant differences among the three walking conditions in stride length, cadence, peak hip extension, hip range of motion (ROM), peak ankle plantar flexion and ankle ROM (All p values < 0.05). The participants walked with increased stride length and decreased cadence during neck level as compared to waist and chest level. They also showed increased ankle ROM and decreased hip ROM as the water depth rose from waist and chest to the neck level. However, our study found no significant difference between waist and chest level water in all variables. Hydrodynamics, such as buoyancy and drag force, in response to changes in water depths, can affect gait patterns during aquatic treadmill walking.  相似文献   

The biomechanical characteristics of high-performance endurance running     

Stephen J. Preece  Christopher Bramah  Duncan Mason 《European Journal of Sport Science》2019,19(6):784-792

The biomechanical profile of high-level endurance runners may represent a useful model that could be used for developing training programmes designed to improve running style. This study, therefore, sought to compare the biomechanical characteristics of high-performance and recreational runners. Kinematic and kinetic measurements were taken during overground running from a cohort of 14 high-performance (8 male) and 14 recreational (8 male) runners, at four speeds ranging from 3.3 to 5.6?m?s^?1. Two-way ANOVA analysis was then used to explore group and speed effects and principal component analysis used to explore the interdependence of the tested variables. The data showed the high-performance runners to have a gait style characterised by an increased vertical velocity of the centre of mass and a flight time that was 11% longer than the recreational group. The high-performance group were also observed to adopt a forefoot strike pattern, to contact the ground with their foot closer to their body and to have a larger ankle moment. Importantly, although observed group differences were mostly independent of speed, the tested variables showed a high degree of interdependence suggesting an underlying unitary phenomenon. This is the first study to compare high-performance and recreational runners across a full range of kinematic and kinetic variables. The results suggest that high-performance runners maintain stride length with a prolonged aerial phase, rather than by landing with a more extended knee. These findings motivate future intervention studies that should investigate whether recreational runners could benefit from instruction to decrease shank inclination at foot contact.  相似文献   

Investigating Identity: Gender,Overseas Experience,and Japanese Youth     

Erina Ogawa 《Journal of Intercultural Communication Research》2019,48(3):185-202

Identity is prominent in academia, despite it being difficult to define and measure due to its dynamic and multifaceted nature. In Japan, awareness of the make-up of Japanese youth is increasingly crucial as Japan becomes a more internationalized and ageing society. This paper examines, by identity mapping and discriminant analysis, the cultural identities of 94 Japanese youth. While strong Global identities separated the respondents with from without overseas experience, ties to National identities and Relationships were found respectively for males and females. This paper suggests that regarding the study of cultural identities, gender does matter – at least in Japan.  相似文献