我国女子持拍隔网对抗类优势项目发展研究——对潜优势项目网球的启示

运用文献资料法、对比研究法和归纳演绎法对我国女子持拍隔网对抗类项目的发展状况进行研究，总结该项群成为优势项目的成功经验，为潜优势项目发展提供借鉴。研究表明体制发展优势、奥运发展战略、完善的后备梯队建设和高水平联赛体系以及技战术创新等是乒乓球、羽毛球运动成为优势项目的主要支持。为实现潜优势项目向优势项目的过渡，应继续优化管理模式、提升教练员执教能力、完善青少年后备人才体系和竞赛机制。     

Spawning dynamics of American shad (Alosa sapidissima) in the St. Lawrence River,Canada–USA

Maltais E, Daigle G, Colbeck G, Dodson JJ. Spawning dynamics of American shad (Alosa sapidissima) in the St. Lawrence River, Canada–USA.
Ecology of Freshwater Fish 2010: 19: 586–594. © 2010 John Wiley & Sons A/S Abstract – The most northerly population of American shad (Alosa sapidissima), located in the St. Lawrence River, is considered vulnerable because of low population abundance and limited spawning habitat located at the upstream extent of the population’s anadromous migration. Here, we aimed to establish the temporal and spatial extent of spawning based on a novel hatch‐date analysis of juveniles. Spawning activity lasted from early May to early July. We found that juveniles captured downstream during the summer hatched later in the year than those captured further upstream. As a result, younger juveniles were distributed somewhat further downstream. In addition, we found significant multimodality in hatch‐date distributions at midstream and downstream sampling stations. Together, these results provide evidence that the 2‐month spawning period involved numerous spawning events that progressed in a downstream direction as the season advanced, rather than being restricted to upstream sites over the spawning season.     

暗期间断在植物生长发育中的应用研究(英文)

暗期间断属于光周期调控技术,被广泛应用于植物的生长发育研究。通过对暗期间断的类型、应用和机理三个方面研究成果进行了综述,其中在暗期间断类型部分总结了光质、间断暗期的次数和间隔时间方面的研究;在暗期间断应用部分总结了在植物形态发生、生理和生物化学方面的相关研究。在此基础上,提出了暗期间断在分子生物学研究及森林资源保护中的应用前景。     

Response of grain yield and related agronomic traits of oilseed flax to diversified cropping rotations北大核心CSCD

This research aimed to identify a suitable planting pattern for oilseed flax production in a dry-farming region. A long-term field experiment was started in 2012 with a 4-year crop rotation cycle,designed to measure the effects on flax crop performance of previous crop,and various patterns of flax planting interval within the four-year rotation,compared with continuous flax cropping. Crop parameters measured included plant height,stem diameter,dry matter accumulation and distribution,and the experiment included six different crop rotation patterns：Flax→flax →flax→flax［（F）FFF］;Flax→wheat→potato→flax［（F）WPF］;Flax→potato→flax→wheat［（F）PFW］;Flax→ flax→wheat→potato［（F）FWP］;Flax→wheat→flax→potato［（F）WFP］and flax→wheat→potato→wheat［（F）WPW］. Results for the ninth year showed significantly increased grain yield（29. 89%-109. 57%）in crop rotation treatments compared with continuous cropping of oilseed flax. The ranking of the six tested rotations for yield was：（F）WPW>（F）FWP>（F）WFP>（F）PFW>（F）WPF>（F）FFF. The grain yield of oilseed flax was significantly affected by previous crop,frequency and years interval of flax cropping and number of years of continuous flax cropping. Yield was increased by 54. 45%-59. 29% under wheat stubble and potato stubble compared with oilseed flax stubble,and increased by 30. 66% and 109. 57%,respectively,under 50% and 25% frequencies,compared with 100% frequency. The grain yield of oilseed flax under two-year continuous cropping was higher by 29. 89% than four-year continuous cropping,and increased with increase in years interval between flax crops. Correlation analysis identified a significantly positive correlation between oilseed flax grain yield and effective capsule number,branch number and 1000-seed weight. The effective capsule number,branch number and 1000-seed weight of oilseed flax under rotation treatment were increased by 35. 88%-108. 91%,15. 47%-46. 19% and 14. 61%-16. 34%,respectively（P<0. 05）,compared with continuous cropping. In addition,the high grain yield of oilseed flax was accompanied by an increase in plant height,stem diameter and dry matter accumulation and these increases were,respectively,5. 11%-42. 24%,2. 77%-39. 92% and 31. 25%-117. 89% under the rotation regimes,compared with continuous cropping. Reduction in the number of years of continuous cropping years,change of crop stubble,decreased flax planting frequency and increased of interval between flax crops also improved flax crop performance. In summary,crop rotation improved the vigor of oilseed flax,resulting in greater plant height and stem diameter,improved dry matter accumulation and distribution,leading to increased branch number,effective capsule number and 1000-seed weight,and increase in the crop yield of oilseed flax. The results indicated that a multiple-crop rotation pattern was an effective way to avoid the yield reduction caused by continuous cropping in oilseed flax. The rotation： Flax→wheat→potato→wheat performed best among those tested and can be recommended as an appropriate cropping rotation for oilseed flax production in the dry region of northwest China. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

应用DHI对某奶牛场奶牛生产性能的综合分析

[目的]为了解奶牛的生产性能.[方法]应用奶牛生产性能测定(DHI)体系,2006年10～11月对武汉市某牛场所有产奶牛的生产情况进行测定和分析.[结果]表明:该场牛群所产奶中体细胞数高,产奶牛中有12%患有临床乳房炎,产犊间隔长,存在繁殖问题和饲料问题,针对测检和分析中发现的问题,提出了相应的改进措施.[结论]为牛场...     

论生物多样性与建设海南国际旅游岛的关系

经过多年的研究和实践,人们已深刻地认识到,海南省的发展战略应该积极发展服务型、开放型和生态型经济,形成以旅游业为龙头、以现代服务业为主导的特色经济结构。显然要实现这个宏伟的目标,生物多样性的保护和持续利用就是最根本和最关键的问题。如果作为生态旅游基本资源的季节性雨林、红树林、海洋生物资源和农业生物多样性被毁,一切都将是一纸空文。本文就拟简略地探讨一下有关这些方面的问题,并提出一些建议供有关方面参考。     

Effects of strategic helminthosis control on age at first lambing and lambing interval of communally grazed Menz ewes in Ethiopia

A three-year longitudinal study was conducted to evaluate effects of strategic anthelmintic treatment regimes on age at first lambing (AFL), weight at first lambing (WFL) and lambing interval (LI) of 356 communally grazed ewes and 675 lambs owned by 10 smallholder farmers in the central highlands of Ethiopia. The ewes were stratified by weight and randomly allocated to three treatment groups as untreated control (TG1), twice-dosed per year (TG2) for both nematodes and trematodes in mid-January and mid-June and four-time-dosed per year (TG3) in June for nematodes, in August–September for nematodes and adult Fasciola, in November–December and January–February for immature flukes. The fixed effect of anthelmintic treatments, parity, season and year of lambing on AFL and LI was evaluated. Mean ± standard error (SE) of lambing interval was 292 ± 3 days. Both anthelmintic treatments (TG2 and TG3) shortened (P < 0.01) LI by about 23 days compared to non-treated ewes (TG1). Season and year of lambing had a significant (P < 0.001) effect on LI. Mean ± SE of AFL and WFL was 598 ± 10 days and 17.2 ± 1.37 kg, respectively. Anthelmintic treatments and parity of dam of the ewe lamb did not affect AFL (P > 0.05). Birth and lambing seasons of the ewe lamb had significant (P < 0.05) effect on AFL. On the other hand, lambing season of the ewe had significant (P < 0.05) effect on WFL. Ewe lambs born in the long rains lambed more than 50 days earlier than the ewe lambs born in short rainy and dry seasons. Lambing occurred year-round with two peaks in August–September and December–January, each 5 months after the two rainy seasons. Anthelmintic treatment at the beginning of the two rainy seasons should improve reproductive performance of Menz ewe lambs in similar agro-ecology in the central highlands of Ethiopia.     

有机磷和菊酯类农药在田间蔬菜上的降解试验

对露天栽培的白菜、茄子和番茄上常用有机磷和菊酯类农药的消减情况进行研究,试验结果表明,敌敌畏是一种降解速度快的农药,施药后1 d,在茄子、番茄和白菜上的降解率分别为66.67%,99%和99.9%,而毒死蜱相对降解速度慢,药后7 d在茄子、番茄和甘蓝上的降解率分别为86.47%,91.59%和97.78%。3种菊酯类农药的降解速度慢,其中以氯氰菊酯的降解速度最快。     

沂蒙山区不同强降雨下土壤的氮素流失特征分析

为探讨不同自然强降雨氮素流失特征,实地观测沂蒙山区孟良崮小流域2010年汛期的降雨与径流过程,选取暴雨(汛期首场强降雨)、大雨(土壤水分相对饱和强降雨)和大暴雨(年最大雨强降雨)3场不同典型强降雨,分析降雨径流及氮素流失特征。结果表明,在首场暴雨条件下,除颗粒态氮外,其他形态氮含量在整个降雨过程中均呈现增加趋势;在大雨过程中,总氮含量在径流峰值前达到峰值,溶解态氮和硝态氮含量在径流峰值后达到峰值,并趋于稳定;在大暴雨条件下,总氮和颗粒态氮含量在径流峰值前浓度陡增到最大后迅速降低。总氮与颗粒态氮的流量加权质量浓度表现为大雨<暴雨<大暴雨,溶解态氮流失浓度百分比介于49.9265%～85.292%,且硝态氮在溶解态氮中占主导地位。不同形态氮和泥沙的平均流失率随着降雨强度的增强而增加,均表现为大暴雨>暴雨>大雨。该研究为沂蒙山区小流域水环境保护和非点源污染治理提供依据。     

利用SCS-CN方法估算流域可收集雨水资源量

流域可收集雨水资源的定量研究对于雨水资源开发利用及其工程规划和建设具有十分重要的意义。该文以北京市门头沟区小流域为研究对象,采用遥感和地理信息系统技术,对流域下垫面特征有关的空间和属性数据进行提取和分析;在此基础上,结合不同水平年降雨资料,运用美国农业部水土保持局(Soil Conservation Service)开发的径流曲线模型(Soil Conservation Service curve number method,SCS-CN),得出不同下垫面特征的径流系数,结合地理信息系统技术生成径流潜力空间分布图。计算了平水年(P=50%)、丰水年(P=25%)、枯水年(P=75%)可收集雨水资源量分别为1.2×107,2.2×107,0.8×107m3;为小流域综合治理和雨水集蓄利用工程的规划与设计提供科学依据。