过早大强度专业化力量训练对足球运动员下肢形态影响的研究     

李振斌  李宏强 《安徽体育科技》2006,27(2):34-36

探讨过早大强度专业化力量训练是否对足球运动员下肢形态存在影响,从而科学地进行足球训练。方法:对原陕西省足球队二级以上的运动员25名与体育院系足球学生25名以及普通高校学生25名的下肢形态的相关指标进行对比。实验结果显示:体育院系学生与普通高校学生的下肢形态没有明显差异(P>0.05);原陕西省足球队与普通高校学生有明显差异(p<0.001),足球队运动员的腿部接近于“O”型以及脚尖略微内扣。结论:过早大强度专业化力量足球训练会对运动员下肢形态存在消极的影响。  相似文献   

Consolidation of Black-dyed Māori Textile Artefacts: Evaluating the Efficacy of Sodium Alginate     

Catherine A. Smith  Rachel A. Paterson  Bronwyn J. Lowe  Rangi Te Kanawa 《文物保护研究》2018,63(3):139-154

Black-dyed artefacts are found in museums worldwide, many produced using an iron-tannate compound. Deterioration of iron-tannate dyed artefacts is an international preservation issue: in New Zealand the deterioration of paru (iron-tannate) dyed Māori textiles is widespread. This article reports experimental work testing the efficacy of sodium alginate, a consolidant developed for deteriorated paru-dyed muka (fibre from harakeke; Phormium tenax). The colour stability, strength retention, and acidity of paru-dyed muka consolidated with sodium alginate (0.25, 0.5, and 1% w/v in water) was tested pre- and post-artificial light ageing. This study found that sodium alginate had no negative effect on paru-dyed muka and in some cases provided benefit. Interestingly, the colour of paru-dyed muka is substantially more stable in UV-filtered light than previously recognised. Also microfading results were in agreement with visual assessments of colour change at 1 Mlux hour exposure, providing confidence in this relatively new technique to assess colour change.  相似文献   

Walking and biologic ageing: Evidence based on NHANES telomere data     

Larry A. Tucker 《Journal of sports sciences》2020,38(9):1026-1035

ABSTRACT

The length of telomeres is an objective measure of biologic ageing. This study evaluated the extent minutes of walking per week are associated with leukocyte telomere length (LTL) in a random sample of 5,823 U.S. adults. The investigation was cross-sectional and data were obtained from the National Health and Nutrition Examination Survey (NHANES). LTL was measured by the quantitative polymerase chain reaction method. Walking minutes was calculated from walking frequency and duration measures. Results showed that for each year of chronological age, telomeres were 15.6 base pairs shorter (P < 0.0001). With walking minutes and LTL treated as continuous variables, the relationship was quadratic, not linear (F = 11.2, P = 0.0023). With walking time divided into three categories, adults who performed ≥ 150 minutes of walking per week had longer telomeres than those who did no regular walking, and those who did some, but less than the recommendation (F = 5.0, P = 0.0137). Regular walkers were estimated to have a biologic ageing advantage associated with 6.5–7.6 years less biologic ageing compared to non-walkers, after adjusting for covariates. Additional investigations designed to study causality and the mechanisms associated with the walking and LTL relationship are needed.  相似文献   

Study of the stability of a series of synthetic colorants applied with styrene-acrylic copolymer, widely used in contemporary paintings, concerning the effects of accelerated ageing     

Zoe Eirini Papliaka  Konstantinos S. Andrikopoulos  Evangelia A. Varella 《Journal of Cultural Heritage》2010,11(4):381-391

This study examines the materials of a contemporary pictorial artwork, belonging to the Macedonian Museum of Contemporary Art in Thessaloniki (Greece), and needing conservation. The combined use of micro-FTIR and micro-Raman spectroscopy allowed the identification of almost all painting materials. Moreover, the stability of a series of synthetic pigments towards accelerated ageing is investigated in applications using the contemporary binding medium styrene-acrylic copolymer. The pigments in question are: Hansa yellow PY3 and PY74, quinacridone PV19 and PR122, naphthol AS PR112, phthalocyanine green PG7 and blue PB15, dioxazine PV37, van Dyck brown PBk11, ivory black PBk9, and titanium dioxide PW6. The organic pigments were applied alone or mixed with titanium dioxide, in rutile form or as a mixture of rutile/anatase. The experimental swatches were subjected to ageing tests, and subsequently studied as to colour changes by means of colorimetric measurements, and as to the molecular structure differentiations by infrared spectroscopy in reflectance mode. The ageing tests included exposure to high temperature and humidity (90 °C, 60% RH) and to ultraviolet radiation (350 nm, 30 °C and 50% RH, with a substantial temperature increase at 90 °C for 3 days). The greater colour difference is caused by high temperature and humidity, whereas paint layers containing TiO₂, and especially the mixture of the forms rutile/anatase, prove very susceptible to ultraviolet radiation, demonstrating a significant colour difference and extended molecular changes.  相似文献   

Later life learning experiences: listening to the voices of Chinese elders in Hong Kong     

Maureen Tam 《International Journal of Lifelong Education》2016,35(5):569-585

Abstract

Governments’ anxieties about ageing populations are mostly concerned with the costs of welfare, care and health provision which all have to be paid for by an ever dwindling working population. However, research in later life learning indicates the significant role that lifelong learning can play in promoting mental well-being and resilience, and in assisting with maintaining personal self-confidence and self-coping strategies that prevent cognitive decline in an ageing population. This paper draws on the research with a group of Chinese elders in Hong Kong, who provide information about their experiences and views on learning in later life, including the meaning of learning, barriers to participation, learning interests, needs, motivations, and instructional preferences. Both quantitative and qualitative findings are reported to shed light on later life learning experiences, which contribute to the global understanding of later life learning and serve to inform the development of policy and practice geared to the planning and provision of opportunities to keep learning at the later stages of life.  相似文献   

胎儿纤维连接蛋白联合宫颈长度在早产预测中的价值     

潘爱萍  居红芳 《泰州职业技术学院学报》2011,11(6):80-81,95

目的探讨胎儿纤维连接蛋白（fFN）联合宫颈长度检测预测早产的价值。方法采用ELISA法检测86例先兆早产孕妇宫颈阴道分泌物中胎儿fFN水平,阴道B超测量其宫颈长度,分析其预测妊娠结局的价值。结果胎儿fFN测定联合宫颈长度预测早产的敏感性、特异性、阳性预测值和阴性预测值分别为97.30%、75.00%、87.80%和100.00%,其特异性、阳性预测值明显高于胎儿fFN及宫颈长度单独检测（P〈0.05）。结论胎儿fFN检测联合宫颈长度对预测早产有较高的价值。  相似文献   

体育教学的教学节奏     

胡承志  杨培岭  袁翠华 《通化师范学院学报》2004,25(2):96-97

在体育教学过程中，为了实现教学目标，教师采取一定“教”的方式，学生也要在教师指导下采取相应的“学”的方式．体育教学中的教学节奏体现了教师主导和学生主体的作用，体育教学中的教学节奏对运动技术、技能的形成和发展有重要作用。  相似文献   

对我国优秀女子标枪运动员早衰现象及其训练学原因的探讨   总被引：1，自引：0，他引：1  

曲淑华  杜超 《四川体育科学》1998,(1)

对我国优秀女子标枪运动员早衰的调查研究表明,我国优秀女子标枪运动寿命比世界选手平均少５．５岁,明显存在早衰现象。从训练学因素研究表明,导致我国女子标枪运动员早衰的原因是：运动负荷过大,基础阶段训练手段单一,大力量练习过多,运动年限较短,过于专项成绩,运动员损伤严重等  相似文献   

The Russian avant-garde painting palette: Documentary and physicochemical codification of organic colorants     

Elli Kampasakali  Evangelia A. Varella   《Journal of Cultural Heritage》2008,9(1):77-88

In the present article an attempt is made to elucidate the organic colorants commonly encountered in the Russian avant-garde painting palette by a combined art historical, documentary and physicochemical investigation, and to examine the influence of environmental factors on the chromatic profile originally sought by the artist. The overall approach based on written sources is confirmed by measurements on relevant paintings. The documentary research deals with the influences of Orthodox iconography, folkloric art, and occidental modernist tendencies on the Russian avant-garde palette, and studies the effects of contradictory historical processes in the chromatic profile of individual paintings. In the experimental section a series of colorants are investigated concerning the effects of accelerated ageing on experimental painting tables, prepared as watercolor and gouache layers on paper ground. The resulting samples are subjected to colorimetric and spectroscopic measurements, and analogous analytical procedures are applied on samples taken from selected paintings. A systematic comparative study of all data permits evaluation of the materials used in terms of their stability towards extrinsic factors, and proposal of degradation routes in order to assist museum curators and conservators in every concrete case related to the broad spectrum of pigments examined.  相似文献   

Learning in Retirement and Old Age: an agenda for the 21st century     

David Istance 《European Journal of Education》2015,50(2):225-238

This article is about education and learning for the ‘retired’. In using this term, it is recognised that any such definitions and given age bands cover a wide range of situations and learning needs. Such diversity should closely inform the educational agenda for older adults, and as it is a life phase defined by challenge and change ‘learning to be’ encapsulates much that is essential to that agenda. The international evidence shows how rapidly our societies are ageing, and how much longer is spent in retirement: so rapid is that change and so large the numbers of seniors and the elderly that the active nature of learning represents a critical aspect of response to this major phenomenon. Contrary to a popular image of declining skills and capacities, the evidence reveals a much more nuanced picture of capability among the retired. Comparisons are drawn with the early childhood sector, which had parallel characteristics but which has since moved rapidly upwards among policy priorities. In conclusion, the article argues that ‘active ageing’ rather than ‘lifelong learning’ represents a more promising embracing framework through which to develop learning in retirement and old age.  相似文献