黑社会的制衡

在校园，黑社会，以及国际事务中，一些组织总是试图用武力从其他组织手中掠夺财物。当他们拥有绝对的实力优势时，便会肆无忌惮地进行攻击，目标是获取财富。有时，个人或组织也会联合起来，组成一个临时聪盟以获取财富或阻止对手的进攻。     

Plasticity of human menstrual blood stem cells derived from the endometrium

Stem cells can be obtained from women’s menstrual blood derived from the endometrium. The cells display stem cell markers such as Oct-4, SSEA-4, Nanog, and c-kit (CD117), and have the potent ability to differentiate into various cell types, including the heart, nerve, bone, cartilage, and fat. There has been no evidence of teratoma, ectopic formation, or any immune response after transplantation into an animal model. These cells quickly regenerate after menstruation and secrete many growth factors to display recurrent angiogenesis. The plasticity and safety of the acquired cells have been demonstrated in many studies. Menstrual blood-derived stem cells (MenSCs) provide an alternative source of adult stem cells for research and application in regenerative medicine. Here we summarize the multipotent properties and the plasticities of MenSCs and other endometrial stem cells from recent studies conducted both in vitro and in vivo.     

A theoretical analysis of the role of social networks in entrepreneurship

Entrepreneurship involves innovation and uncertainty. We outline a theory of entrepreneurship, which highlights the importance of social networks in promoting innovation and reducing uncertainty. Our findings suggest that this “social” aspect of entrepreneurship increases the probability of entrepreneurial success. The results also lend credence to theories of entrepreneurship that suggest that entrepreneurial opportunities are formed endogenously by the entrepreneurs who create them. We also consider the public policy implications of our findings.     

Validity and reliability of GPS for measuring distance travelled in field-based team sports

Abstract

The aim of the present study was to examine the effects of movement intensity and path linearity on global positioning system (GPS) distance validity and reliability. One participant wore eight 1-Hz GPS receivers while walking, jogging, running, and sprinting over linear and non-linear 200-m courses. Five trials were performed at each intensity of movement on each 200-m course. One receiver was excluded from analysis due to errors during data collection. The results from seven GPS receivers showed the mean (±s) and percent bias of the GPS distance values on the 200-m linear course were 205.8 ± 2.4 m (2.8%), 201.8 ± 2.8 m (0.8%), 203.1 ± 2.2 m (1.5%), and 205.2 ± 4 m (2.5%) for the walk, jog, run, and sprint trial respectively. Walk and sprint distances were significantly different from jogging and running distances (P < 0.05). The GPS distance values on the 200-m non-linear course were 198.9 ± 3.5 m (?0.5%), 188.3 ± 2 m (?5.8%), 184.6 ± 2.9 m (?7.7%), and 180.4 ± 5.7 m (?9.8%) for the walk, jog, run, and sprint trial respectively; these were significantly lower than those for the corresponding values on the linear course (P < 0.05). Differences between all non-linear movement intensities were significant (P < 0.05). The overall coefficient of variation within and between receivers was 2.6% and 2.8% respectively. Path linearity and movement intensity appear to affect GPS distance accuracy via inherent positioning errors, update rate, and conditions of use; reliability decreases with movement intensity.     

Book reviews

William J. Baker and James A. Rog (eds.), Sports and the Humanities: A Symposium (University of Maine, Orono, Maine, 1983), Pp.126. $8.95.

William J. Baker, Sports in the Western World. (Totowa, N.J., Rowan and Littlefield, 1982), Pp.viii + 360. $19.95 (hardback).

J. Bale, Sport and Place: A Geography of Sport in England, Scotland and Wales. (London, C. Hurst; Lincoln, University of Nebraska Press, 1982). Pp.187 £9.50.

J. A. Mangan, Athleticism in the Victorian and Edwardian Public School: the Emergence and Consolidation of an Educational Ideology. (Cambridge, Cambridge University Press, 1981). Pp.368. £28.

Beryl Furlong, Carnegie 1933–1983: College and School. (University of Liverpool, 1983). Pp.40. NP.

Gerald Redmond, The Sporting Scots of Nineteenth‐Century Canada. (London and Toronto, Associated University Presses, 1982). Pp.347. £16.50 (hardback).

Steven Tischler, Footballers and Businessmen (New York, Holmes and Meier, 1981). Pp.154.     

An Analysis of Anatomy Education Before and During Covid-19: May–August 2020

Coronavirus disease 2019 (Covid-19) created unparalleled challenges to anatomy education. Gross anatomy education has been particularly impacted given the traditional in-person format of didactic instruction and/or laboratory component(s). To assess the changes in gross anatomy lecture and laboratory instruction, assessment, and teaching resources utilized as a result of Covid-19, a survey was distributed to gross anatomy educators through professional associations and listservs. Of the 67 survey responses received for the May–August 2020 academic period, 84% were from United States (US) institutions, while 16% were internationally based. Respondents indicated that in-person lecture decreased during Covid-19 (before: 76%, during: 8%, P < 0.001) and use of cadaver materials declined (before: 76 ± 33%, during: 34 ± 43%, P < 0.001). The use of cadaver materials in laboratories decreased during Covid-19 across academic programs, stand-alone and integrated anatomy courses, and private and public institutions (P ≤ 0.004). Before Covid-19, cadaveric materials used in laboratories were greater among professional health programs relative to medical and undergraduate programs (P ≤ 0.03) and among stand-alone relative to integrated anatomy courses (P ≤ 0.03). Furthermore, computer-based assessment increased (P < 0.001) and assessment materials changed from cadaveric material to images (P < 0.03) during Covid-19, even though assessment structure was not different (P > 0.05). The use of digital teaching resources increased during Covid-19 (P < 0.001), with reports of increased use of in-house created content, BlueLink, and Complete Anatomy software (P < 0.05). While primarily representing US institutions, this study provided evidence of how anatomy educators adapted their courses, largely through virtual mediums, and modified laboratory protocols during the initial emergence of the Covid-19 pandemic.     

Expansive learning in a change laboratory intervention for teachers

The theory of Expansive learning and the change laboratory (CL) methodology has been developed and applied in many studies on workplace learning and educational change. There are fewer studies made on small-scale interventions, exploring the longitudinal development of expansive learning in an educational change effort. This article examines a CL intervention performed in an upper secondary school in Sweden, with a small group of teachers engaged in a participatory design project. By identifying and analysing the relationship of the seven learning actions posited by the theory of expansive learning, the aim was to contribute to the discussion of the CL methodology and the empirical usability of the theory. The results showed that the seven expansive learning actions functioned as analytical tools to map the teachers learning and development, but the analysis also showed many deviations, disruptions and occurrence of practical actions of design in the process. This challenge the notions of cyclicity and ascension in the theory of expansive learning. Cyclicity might be desirable but not necessary for expansive learning which questions the need to first grasp the problem at a conceptual level before generating concrete solutions. The Findings in this study suggests the opposite; that the entanglement and parallel movement between the abstract and the concrete was a driving force for the teachers expansive learning and the design of new curricular units.

     

Tuition-Setting Authority and Broad-Based Merit Aid: The Effect of Policy Intersection on Pricing Strategies

The notion of merit-aid is not a new development in higher education. Although previous researchers have demonstrated the impact of state-adopted merit-aid funding on student decision-making, fewer studies have examined institutional pricing responses to broad-based merit-aid policies. Using a generalized difference-in-difference approach, we extend previous empirical work by examining the impact of merit-aid on institutional pricing strategies while considering both the institution’s tuition-setting authority and the relative strength of the merit-aid program. In this study, we find that colleges and universities with the authority to set their own tuition increased their in-state tuition and fees following broad-based merit-aid policy adoption; however, institutions with state-controlled tuition-setting authority respond to broad-based merit-aid policies by lowering their in-state tuition and fees. Our findings suggest that the incentives and dynamics of each state’s policy environment are significant determinants of institutional responses to state-level policy adoptions.