The effect of 14 weeks of vitamin D3 supplementation on antimicrobial peptides and proteins in athletes

Heavy training is associated with increased respiratory infection risk and antimicrobial proteins are important in defence against oral and respiratory tract infections. We examined the effect of 14 weeks of vitamin D₃ supplementation (5000 IU/day) on the resting plasma cathelicidin concentration and the salivary secretion rates of secretory immunoglobulin A (SIgA), cathelicidin, lactoferrin and lysozyme in athletes during a winter training period. Blood and saliva were obtained at the start of the study from 39 healthy men who were randomly allocated to vitamin D₃ supplement or placebo. Blood samples were also collected at the end of the study; saliva samples were collected after 7 and 14 weeks. Plasma total 25(OH)D concentration increased by 130% in the vitamin D₃ group and decreased by 43% in the placebo group (both P = 0.001). The percentage change of plasma cathelicidin concentration in the vitamin D₃ group was higher than in the placebo group (P = 0.025). Only in the vitamin D₃ group, the saliva SIgA and cathelicidin secretion rates increased over time (both P = 0.03). A daily 5000 IU vitamin D₃ supplement has a beneficial effect in up-regulating the expression of SIgA and cathelicidin in athletes during a winter training period, which could improve resistance to respiratory infections.     

矿井轴流式主要通风机经济运行探讨

轴流式通风机是煤矿常用的一种通风设备，用于矿井通风的轴流式风机，不仅功率大而且长时运转，因此，它是煤矿耗电量较大的机械设备之一。针对轴流式风机能量损失的一些原因作以分析，并提出使之可达到经济运行的若干技术措施。     

高校现金流量表编制的依据与编制方法初探

随着我国高等教育事业的发展,高校财务活动已不再是简单的取得财政、事业收入,拨缴规定款项,和核算相关支出。作为会计主体,高校会计核算的内容正逐步走向多样化、复杂化。鉴于这种情况,应尽快在高校财务报表体系中增加现金流量表,全面反映一个学校一定会计期间现金流入、流出和净增加(减少)情况,以改变现行高校会计信息披露不完整,决策依据不充分的现状。     

中国基础研究类高层次科技人才流动特征分析 ——以环境领域为例

探寻我国基础研究类科技人才,尤其是高层次科技人才的流动特征和规律,对于制定我国基础研究类科技 人才发现、培养和发展的政策具有重要意义。本文以环境领域国家杰出青年科学基金获得者为研究对象,对中国该领 域基础研究类高层次科技人才的机构流动和国别流动特征进行分析。基于马斯洛需求理论,进一步对不同动机产生的 人才流动所对应的年龄分布进行探讨,为我国基础研究类高层次科技人才的政策制定提供参考和借鉴。     

Visual body pedagogies: how anti-oppressive education informs the teaching and learning of sporting bodies

In this article, the authors borrow from anti-oppressive education theory for its potential to disrupt how students visually conceive sporting bodies and to problematize the teaching and learning of these bodies within undergraduate physical education (PE) programs. Fourteen photo stories produced by students enrolled in PE programs at two universities were analysed using a semiotic approach to excavate the emergent themes of sporting bodies from the narratives. Relying on Kumashiro's anti-oppressive educational theoretical framework, the authors found that most of stories reified discursive practices that (re)produce gender oppression in sport. Despite these findings, the authors also discovered anti-oppressive pedagogies are useful for teaching against the body oppressions conveyed in the photo stories. How anti-oppressive education informs other areas of PE should be examined in the future.     

自力式流量控制器在热网中的应用

开滦荆各庄热水采暖系统98年以前采用普通阀门调节流量，定量困难，由于在检修过程中频繁开关，导致调节功能失效，供暖用户冷热不均。自98年后逐步改用了自力式流量控制器进行流量控制，改后，在使用过程中解决了以往存在的各种问题，实现了节能节水的效果。     

从评价到决策:科学逻辑研究的可能转向

科学评价问题是科学逻辑的核心。科学理性不是体现在存在科学评价的逻辑上，而是体现在科学的决策之中。科学决策机制是一个特殊的“投票体制”，它与科学理性的关系，将是科学逻辑研究的一个可能转向。“科学决策”的研究方向将涉及到多个学科，如科学史学、科学社会学、逻辑学，它同时可以借鉴博弈论、经济学、政治学等学科里的研究成果，这将是一个富于成果的研究方向。     

连续定态传热过程平均温差的统一推导

采用统一的方法对定态传热逆流和并流的平均温差进行了推导。推导过程无需假定冷热流体的特定流向,并利于得到对数平均温差“同侧相减”的规律。     

人造金刚石提纯废水处理沉淀池的设计

本文对人造金刚石提纯废水进行了研究,在试验和分析的基础上,根据生产实际设计出科学实用的竖流式沉淀池,可对悬浮固体的有用成分进行回收,能取得一定的经济效益。     

Numerical investigation of cavitating flow behind the cone of a poppet valve in water hydraulic system

Computational Fluid Dynamics (CFD) simulations of cavitating flow through water hydraulic poppet valves were performed using advanced RNGk-epsilon turbulence model. The flow was turbulent, incompressible and unsteady, for Reynolds numbers greater than 43000. The working fluid was water, and the structure of the valve was simplified as a two dimensional axisymmetric geometrical model. Flow field visualization was numerically achieved. The effects of inlet velocity, outlet pressure, opening size as well as poppet angle on cavitation intensity in the poppet valve were numerically investigated. Experimental flow visualization was conducted to capture cavitation images near the orifice in the poppet valve with 30° poppet angle using high speed video camera. The binary cavitating flow field distribution obtained from digital processing of the original cavitation image showed a good agreement with the numerical result. Project supported by the National Natural Science Foundation of China (No. 59835160) and Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry of China (No. 50175097)