Reliability and validity of a modified 3-minute all-out swimming test in elite swimmers     

Lachlan J. G. Mitchell  David B. Pyne  Philo U. Saunders  Ben Rattray 《European Journal of Sport Science》2018,18(3):307-314

Critical speed (CS) testing is useful in monitoring training in swimmers, however, completing a series of time trials (TTs) regularly is time-consuming. The 3-minute test may be a solution with positive initial findings. This investigation examined whether a modified 3-minute test (12?×?25?m) could assess CS and supra-CS distance capacity (D’) in swimmers. A series of 12?×?25?m intervals were completed unpaced at maximal effort, interspersed with 5?s rest periods. The model speed?=?a e^{b t}?+?c was fitted to the data and integrated to calculate D’. The slowest two of the last four efforts were averaged to calculate CS. To assess reliability, 15 highly trained swimmers (9 females, 6 males) completed the 12?×?25?m twice within 72?h. Four measures were deemed reliable: peak velocity (0.01?m?s^?1; 0.5%, typical error and % coefficient of variation), CS (0.02?m?s^?1; 1.2%), D’ (1.22?m; 5.7%) and drop off % (0.70% points; 4.5%). To assess criterion validity, 21 swimmers (9 from reliability, 12 other) completed two competition races within 2 weeks of a 12?×?25?m in the same stroke. Traditional CS and D’ measures were calculated from competition performances (TT method). TT CS and 12?×?25?m CS were highly correlated (adj. R²?=?0.92, p?D’ values were moderately correlated (adj. R²?=?0.60, p?D’ accurately. The 12?×?25?m all-out swimming test is a reliable method for assessing CS and D’ in swimmers, however, the validity of D’ requires further investigation.  相似文献   

Preparation,Characterization and Cytotoxic Effects of Pegylated Nanoliposomal Containing Carboplatin on Ovarian Cancer Cell Lines     

Meysam Ebrahimifar  Amir Nili-Ahmadabadi  Azim Akbarzadeh  Hasan Ebrahimi Shahemabadi  Majid Hasanzadegan  Hemen Moradi-Sardareh  Hassan Madadizadeh  Jalal Rezaee-diyan 《Indian journal of clinical biochemistry : IJCB》2017,32(2):230-234

Carboplatin is a chemotherapeutic agent used against various malignancies such as ovarian carcinoma. The aim of this study is to improve the therapeutic efficacy of carboplatin using pegylated liposomal nanocarriers. Nanoparticles were synthesized using thin film hydration technique and characterized for shape morphology, particle size, zeta potential and drug-release properties. In the next step, A2780S and A2780CP ovarian cancer cell lines were used to determine the efficacy of nanodrug by MTT assay. The particle size and zeta potential of nanodrug were measured 244.3 ± 19.6 nm and ?22.9 ± 1.7 mV, respectively. High encapsulation capacity (78.6 ± 3.7 %) confirmed the efficiency of technique. The cytotoxicity results also showed that nanodrug compared to free drug improve the efficacy of carboplatin against both A2780S (P < 0.01) and A2780CP (P < 0.05) cell lines. In conclusion, the findings of our study suggested pegylated liposomal nanocarriers are proper for carboplatin delivery to ovarian cancer cell lines A2780S and A2780CP.  相似文献   

Socioeconomic Implications of Telecommunications Liberalization: India in the International Context     

Ben A. Petrazzini Girija Krishnaswamy 《The Information Society》1998,14(1):3-18

Telecommunications restructuring have evolved differently in Asia and Latin America. While Asian governments have moved cautiously in bringing changes to the sector, Latin American nations have implemented radical ownership and market transformations. The Indian telecommunications reform falls in between these two general regional trends. The choice of a high component of competition, increased private participation, and no privatization of the national carrier set conditions that will trigger unique socioeconomic effects. This article identifies and highlights the likely implications of the Indian reform on key economic and social issues, such as the cost of services, cross-subsidies, network interconnection, private investments, universal services, employment, and the possible rise of an information-intensive economy. It does so by comparing and contrasting the Indian experience with dominant reform strategies elsewhere in the developing world.  相似文献   

Equity in college physics student learning: A critical quantitative intersectionality investigation     

Ben Van Dusen  Jayson Nissen 《科学教学研究杂志》2020,57(1):33-57

We investigated the intersectional nature of race/racism and gender/sexism in broad scale inequities in physics student learning using a critical quantitative intersectionality. To provide transparency and create a nuanced picture of learning, we problematized the measurement of equity by using two competing operationalizations of equity: Equity of Individuality and Equality of Learning. These two models led to conflicting conclusions. The analyses used hierarchical linear models to examine student's conceptual learning as measured by gains in scores on research-based assessments administered as pretests and posttests. The data came from the Learning About STEM Student Outcomes' (LASSO) national database and included data from 13,857 students in 187 first-semester college physics courses. Findings showed differences in student gains across gender and race. Large gender differences existed for White and Hispanic students but not for Asian, Black, and Pacific Islander students. The models predicted larger gains for students in collaborative learning than in lecture-based courses. The Equity of Individuality operationalization indicated that collaborative instruction improved equity because all groups learned more with collaborative learning. The Equality of Learning operationalization indicated that collaborative instruction did not improve equity because differences between groups were unaffected. We discuss the implications of these mixed findings and identify areas for future research using critical quantitative perspectives in education research.  相似文献   

杭州大雪的气候诊断分析     

查贲  张炎  方汉杰 《科技通报》2010,26(1):63-66,76

通过对杭州1951年以来的48个大雪个例资料,结合海温、大气环流特征资料进行周期分析、突变检测、相关分析,给出杭州大雪出现频次的周期、突变点,发现大雪出现频次、降雪强度与海温冷暖事件存在高关联．特别是与NINO1＋2区海温存在密切的联系,根据所得结论可以较好的对大雪发生趋势作出预测。  相似文献   

铝电解故障诊断的研究现状及发展趋势     

周昊  李界家  李世涛  王奔 《科技广场》2010,(9)

铝电解是一个非线性、多耦合、时变和大时滞过程,受强电场、强磁场、强热场交互干扰,故障发生频繁。本文综述了国内外铝电解故障诊断研究状况,阐述了目前铝电解故障诊断的主要方法和发展趋势,为铝电解故障诊断技术的实用化提供理论依据。  相似文献   

适应人工智能快速发展的知识产权制度研究     

余翔  张润哲张奔 王华 《科研管理》2021,42(8):176-183

基于深度学习算法的进步,人工智能逐渐有能力独立进行发明创造和文艺作品创作。本文主要探讨现行专利及著作权制度中规定的保护对象、权利人资格、专利及著作权的权属、侵权判定、侵权责任主体等对人工智能技术快速发展的适应及协调程度,研究指出：现有的专利和版权制度应当对人工智能的发明和作品持鼓励的态度,在排除不适宜作为专利或著作权保护对象的同时,人工智能的发明或作品的权利授予标准应当与人类的有所区分;相关权利人仍须对应自然人或法人,而非人工智能本身;相关专利侵权行为应包括间接侵权,同时应对人工智能作品安排“登记-授权”的著作权制度、参考临摹作品为人工智能绘画作品提供相应的授权使用制度等。本文还探讨了当前的专利法及著作权法在人工智能时代符合公平原则的程度,并提出解决方案：在“强人工智能时代”将人工智能的发明创造或作品作为公共财产,授予相应的开发者“数据处理权”作为一种新的邻接权,赋予人工智能创造物新的特别权利（Sui Generis）,修改专利法与著作权法中关于主要权利的相关规定等。  相似文献   

Using causal models to bridge the divide between big data and educational theory     

Kirsty Kitto  Ben Hicks  Simon Buckingham Shum 《British journal of educational technology : journal of the Council for Educational Technology》2023,54(5):1095-1124

An extraordinary amount of data is becoming available in educational settings, collected from a wide range of Educational Technology tools and services. This creates opportunities for using methods from Artificial Intelligence and Learning Analytics (LA) to improve learning and the environments in which it occurs. And yet, analytics results produced using these methods often fail to link to theoretical concepts from the learning sciences, making them difficult for educators to trust, interpret and act upon. At the same time, many of our educational theories are difficult to formalise into testable models that link to educational data. New methodologies are required to formalise the bridge between big data and educational theory. This paper demonstrates how causal modelling can help to close this gap. It introduces the apparatus of causal modelling, and shows how it can be applied to well-known problems in LA to yield new insights. We conclude with a consideration of what causal modelling adds to the theory-versus-data debate in education, and extend an invitation to other investigators to join this exciting programme of research.

Practitioner notes

What is already known about this topic

• ‘Correlation does not equal causation’ is a familiar claim in many fields of research but increasingly we see the need for a causal understanding of our educational systems.
• Big data bring many opportunities for analysis in education, but also a risk that results will fail to replicate in new contexts.
• Causal inference is a well-developed approach for extracting causal relationships from data, but is yet to become widely used in the learning sciences.

What this paper adds

• An overview of causal modelling to support educational data scientists interested in adopting this promising approach.
• A demonstration of how constructing causal models forces us to more explicitly specify the claims of educational theories.
• An understanding of how we can link educational datasets to theoretical constructs represented as causal models so formulating empirical tests of the educational theories that they represent.

Implications for practice and/or policy

• Causal models can help us to explicitly specify educational theories in a testable format.
• It is sometimes possible to make causal inferences from educational data if we understand our system well enough to construct a sufficiently explicit theoretical model.
• Learning Analysts should work to specify more causal models and test their predictions, as this would advance our theoretical understanding of many educational systems.

  相似文献   

Implementation Factors and Their Influence on Student Mathematics Outcomes     

Tasia Brafford  Beth Harn  Ben Clarke  Christian T. Doabler  Derek Kosty  Kathleen Scalise 《Learning disabilities research & practice》2023,38(1):5-14

Assessing implementation allows for a better understanding of an intervention's effects and the mechanisms that influence its impact. Two main areas of implementation are (a) the quality with which an intervention is delivered and (b) instructors’ adherence to the programmed intervention. The current study used data from a kindergarten mathematics intervention program to (a) examine if and how treatment adherence was associated with implementation quality and (b) explore implementation measures’ relation to student mathematics outcomes. Results indicated high implementation scores across time for both adherence and quality. Neither treatment adherence nor implementation quality was found to relate to a general outcome measure of student mathematics achievement; however, both were similarly related to the curricular-aligned measure.  相似文献   

电子对抗专业应用型人才实践教学研究 ——以"电子对抗技术与指挥"人才培养方案为例     

任明秋  王冰切  冷毅  商犇 《高等教育研究学报》2022,45(1):116-120

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