不能生育的雌鸽     

J·P·史托斯高夫  刘正光 《环球赛鸽科技》2004,(6)

造成雌鸽不能生育的情况的原因一定是很多的,作者以自己养鸽生涯中的经验,历数种种可能,想必会对你有所启发。这是一个广义的概念,涉及从先天性不育到老年不育的各个方面,包括相对性不育,即雌鸽产蛋少、产蛋不正常(比如无壳蛋),也可能是个别雌鸽不育,出现雏鸽  相似文献   

幼鸽日益消瘦的问题     

J·P·杜夏尔  刘正光 《环球赛鸽科技》2006,(1)

每年春季,比利时各地的鸽友都在抱怨一种疾病,一般称其为鸽腺病毒病。这究竟是种什么疾病呢?有些科研人员把这种疾病规为圆环病毒 (circovirus),一种极少有人知道的病毒。为了使问题更明确一些,我们把这问题转告了吉恩·皮埃尔·杜夏尔(Jean Pierre Duchatel),他在列日大学兽医系工作。需告诉大家的是,吉恩·皮埃尔·杜夏尔先生也是位鸽友,而且自1974年以来就是鸟类医学系的成员,一直与文德夫格教授(Vindevogel)共事。他们一起深入研究感染鸽子的各类病毒,并为Fort Dodge公司研制了多种疫苗,如 Colombovac PMV(副粘病毒疫苗),Colombovac Pox (鸽痘病毒)和Colombovac Paratyphus (副伤寒病毒)。目前,杜夏尔先生正负责一项由FCI(国际赛鸽联合总会)出资扶植的研究项目,研究可传染给信鸽的圆环病毒。  相似文献   

贸易,就业与工资     

Krug.  P 朱疆 《科学中国》1994,(8):6-10

  相似文献   

Success in elite cycling: A prospective and retrospective analysis of race results     

Schumacher YO  Mroz R  Mueller P  Schmid A  Ruecker G 《Journal of sports sciences》2006,24(11):1149-1156

The development of peak performances is a main research focus in sports science. It is unclear how many former top junior athletes achieve success in the elite class later. The aim of the present study was to examine the careers of athletes who participated in major junior or adult/elite cycling events using prospective and retrospective analysis of competition results. The official results of major junior (age < or = 18 years) and elite (age > 18 years) cycling races from 1980 to 2004 were analysed. Age-related aspects, career lengths, and success were compared between riders who presented results in both junior and elite races (JUNIOR ELITE) and riders who had no junior race results (ELITE ONLY). Altogether, 27,454 results of 8004 athletes from 108 countries were collected. We found that 29.4% of the elite athletes had participated in junior World Championships, and that 34% of the participants in junior World Championships later participated in major elite competitions. JUNIOR ELITE athletes are significantly more successful in several cycling disciplines and have their first and last elite result at a younger age than ELITE ONLY athletes. No difference was found in career lengths. The data presented here emphasize the importance of long-term training programmes in the development of peak performance in cycling.  相似文献   

意大利14岁以下儿童的排球启蒙理念   总被引：2，自引：0，他引：2  

潘迎旭 《中国排球》2004,(3)

中国排球运动在过去的发展过程中曾经创造过历史性的辉煌和令人瞩目的成就,但近年来青少年后备力量的萎缩却极大地影响了其前进的速度和步伐。为了促进中国排球运动今后的持续、健康发展,必须加强对青少年排球后备力量培养工作的研究,努力培养出更多的优秀后备人才。但是,目前国内对青少年排球训练和培养的专门研究和探讨却不多,尤其缺乏对当今世界上一些排球强国的青少年排球训练理念和特点的研究及探讨。这里,笔者根据有关的文献和资料,对意大利14岁以下年龄组儿童的排球启蒙训练  相似文献   

Elite football on artificial turf versus natural grass: movement patterns, technical standards, and player impressions     

Andersson H  Ekblom B  Krustrup P 《Journal of sports sciences》2008,26(2):113-122

The aim of the present study was to examine the movement patterns, ball skills, and the impressions of Swedish elite football players during competitive games on artificial turf and natural grass. Time - motion analyses (36 observations) and technical analyses (16 team observations) were performed and 72 male and 21 female players completed a questionnaire. No differences were observed between artificial turf and natural grass in terms of total distance covered (mean 10.19 km, s = 0.19 vs. 10.33 km, s = 0.23), high-intensity running (1.86 km, s = 0.10 vs. 1.87 km, s = 0.14), number of sprints (21, s = 1 vs. 22, s = 2), standing tackles (10, s = 1 vs. 11, s = 1) or headers per game (8, s = 1 vs. 8, s = 1), whereas there were fewer sliding tackles (P < 0.05) on artificial turf than natural grass (2.1, s = 0.5 vs. 4.3, s = 0.6). There were more short passes (218, s = 14 vs. 167, s = 12) and midfield-to-midfield passes (148, s = 11 vs. 107, s = 8) (both P < 0.05) on artificial turf than natural grass. On a scale of 0-10, where 0 = "better than", 5 = "equal to", and 10 = "worse than", the male players reported a negative overall impression (8.3, s = 0.2), poorer ball control (7.3, s = 0.3), and greater physical effort (7.2, s = 0.2) on artificial turf than natural grass. In conclusion, the running activities and technical standard were similar during games on artificial turf and natural grass. However, fewer sliding tackles and more short passes were performed during games on artificial turf. The observed change in playing style could partly explain the male players' negative impression of artificial turf.  相似文献   

Science and technology policy in France: 1981–1986     

Papon P 《Minerva》1988,26(4):493-511

  相似文献   

Beyond online: primary research as a value-added service     

Jajko P 《Medical reference services quarterly》1992,11(2):67-78

Information specialists should provide a value-added service by supplementing their online searches with primary research. Primary research results in more up-to-date information from a broader spectrum of sources. The requester benefits from primary research by receiving a cost-effective and more comprehensive information package. The information professional benefits by acquiring a more in-depth knowledge of the subject, increasing awareness of important projects within the organization, and achieving recognition as a key information analyst.  相似文献   

Hospital and corporate information services: introducing a new column     

Jajko P 《Medical reference services quarterly》1992,11(1):63-66

Successful hospital and corporate libraries offer customized resources and services to meet the needs of their dynamic organizations. Concepts such as customer-driven, service-oriented and value-added are central to these libraries. Serving decision makers and integrating the library into the decision-making process of the organization is critical. Future articles in this new column will further explore the underlying philosophies and the specialized resources and services that characterize these libraries.  相似文献   

Rates and psychological effects of exposure to family violence among Sri Lankan university students     

Haj-Yahia MM  de Zoysa P 《Child abuse & neglect》2008,32(10):994-1002

  相似文献