The effect of inspiratory muscle fatigue on acid-base status and performance during race-paced middle-distance swimming

The aim of this study was to investigate the effect of pre-induced inspiratory muscle fatigue (IMF) on race-paced swimming and acid-base status. Twenty-one collegiate swimmers performed two discontinuous 400-m race-paced swims on separate days, with (IMF trial) and without (control trial) pre-induced IMF. Swimming characteristics, inspiratory and expiratory mouth pressures, and blood parameters were recorded. IMF and expiratory muscle fatigue (P < 0.05) were evident after both trials and swimming time was slower (P < 0.05) from 150-m following IMF inducement. Pre-induced IMF increased pH before the swim (P < 0.01) and reduced bicarbonate (P < 0.05) and the pressure of carbon dioxide (PCO₂) (P < 0.05). pH (P < 0.05), bicarbonate (P < 0.01) and PCO₂ (P < 0.05) were lower during swimming in the IMF trial. Blood lactate was similar before both trials (P > 0.05) but was higher (P < 0.01) in the IMF trial after swimming. Pre-induced IMF induced respiratory alkalosis, reduced bicarbonate buffering capacity and slowed swimming speed. Pre-induced and propulsion-induced IMF reflected metabolic acidosis arising from dual role breathing and propulsion muscle fatigue.     

低氧暴露后提高平原运动能力的非血液学机制

在过去五十多年中,高原训练常被应用于优秀耐力运动员,旨在提高其平原的运动能力.大多研究认为,高原适应的优势主要集中在血液学方面,即提主平原运动能力的主要机制是高原环境下氧气利用下降激发红细胞生成加速反应,从而起红细胞量、 VO2max和竞技能力的提高.     

Select Books – the struggle of an independent bookshop

Abstract

This is a first‐hand account of the initial 28 years of Select Books, an independent bookshop, located in Singapore, but with a regional Southeast Asian focus and a global reach. Select Books carved a niche for itself by specializing in books about Southeast Asia and published in Southeast Asia. Its comprehensive and in‐depth book stock gave it an edge over formidable competition at home and abroad. The author relates the difficulties encountered and the novel solutions Select Books employed to overcome administrative problems and sidestep bureaucratic red tape. Select Books operated on all levels of the book trade: as bookseller, distributor, library supplier and publisher. Equally important is its intangible role as a promoter of Southeast Asian authors and their works in Singapore as well as to the first world. Select Books provided a cultural space where authors could meet with their readership. Turning to the broader book community, the author is critical of the Eurocentric mindsets of public and academic institutions in Singapore. She is equally critical of the parochial and prejudiced international market that dismisses books about Asia as insufficiently ‘mainstream’ for their market.     

A group recommendation system for online communities

Online communities are virtual spaces over the Internet in which a group of people with similar interests or purposes interact with others and share information. To support group activities in online communities, a group recommendation procedure is needed. Though there have been attempts to establish group recommendation, they focus on off-line environments. Further, aggregating individuals’ preferences into a group preference or merging individual recommendations into group recommendations—an essential component of group recommendation—often results in dissatisfaction of a small number of group members while satisfying the majority. To support group activities in online communities, this paper proposes an improved group recommendation procedure that improves not only the group recommendation effectiveness but also the satisfaction of individual group members. It consists of two phases. The first phase was to generate a recommendation set for a group using the typical collaborative filtering method that most existing group recommendation systems utilize. The second phase was to remove irrelevant items from the recommendation set in order to improve satisfaction of individual members’ preferences. We built a prototype system and performed experiments. Our experiment results showed that the proposed system has consistently higher precision and individual members are more satisfied.     

论篮球战术系统

运用逻辑方法分析了篮球战术及相关概念,通过内涵定义与外延定义明确了篮球战术的特征和分类;运用系统方法从系统的整体性、关联性和动态性等方面论述了篮球战术系统的结构、功能及系统的发展规律.