高寒围栏草地短期放牧育肥牦牛增重试验

选择 40头成年阉牦牛 ,( 2 0头为试验组、2 0头为对照组 ) ,进行围栏草地上短期放牧育肥试验。结果 ,在围栏草地上放牧育肥的试验组阉牦牛 ,试验组每头牦牛的总增重比对照组提高 3 .3 1kg ,平均日增重 83g ,提高 44 % ,(P <0 .0 1)。试验组比对照组牦牛每头分别增收 2 6.48元     

北京通州新通国际花园景观设计

通过对北京通州新通国际花园居住区的背景概述、基地分析、设计依据与定位目标分析,提出了项目的设计原则、设计理念和设计方案。认为,设计应以满足居住者的需求为着力点,社区景观规划应遵循＂公共—半公共—私密＂的逻辑递进关系,强调点线面的相互结合统一。     

Intensive beach management as an improved sea turtle conservation strategy in Mexico

We evaluate the role of intensive beach management, meaning intense patrolling and nest reburial to a central hatchery, as a strategy for improving the success of sea turtle conservation at nesting sites in Mexico. We report the results of an experimental program at Playa Cuixmala, Jalisco, western Mexico. Sea turtle conservation efforts in Mexico have, in general, poor results because of lack of funds, which leads to insufficient beach protection and severe negative effects of nest removal on hatching success and sex ratios. Alternative strategies are needed to optimize limited resources. We predicted that intensive beach management, which included intense patrolling and careful nest reburial, could be an effective way to maximize nest survival and hatchling release under limited financial and human resources. The results of our 9-year study were very positive. Survival rate increased several fold during the study period. Hatching success and sex ratios were not significantly different between in-situ and removed nests. Survival in removed nests was, however, much higher that in-situ nests, because of predation and beach erosion. In total, the small (3 km length) Playa Cuixmala became the second most productive sea turtle nesting beach in the region because of these concentrated efforts. Intense beach management can be an important technique for sea turtle conservation, and can be properly applied to small beaches or the most productive sections of large beaches.     

江油市低效天然林封禁试验初步研究

连续2a对低效天然林封禁试验进行了初步研究。结果表明：（1）封禁1a后,乔木层郁闭度提高8．3％～16．7％,灌木层覆盖度提高15．2％～64．7％,草本层覆盖度提高12．5％～20．0％;封禁2a后,乔木层郁闭度提高16．7％～33．3％,灌木层覆盖度提高39．4％～141．2％,草本层覆盖度提高37．5％-44．0％。（2）封禁与不封禁的林分郁闲度、灌木和草本盖度和林分总生物量均达到差异极显著水平。     

围隔海域水质评价及底栖曲浒苔对水质修复能力评估研究

于2015年1—12月对杭州湾北部沿岸碧海金沙围隔海域水环境质量进行每月一次的跟踪监测,进行围隔海域水质分析评价,通过调查底栖浒苔群落的种类组成及其生物量,评估其对围隔海域水质的修复能力。根据富营养化状态指数(E)表明,2015年该围隔海域1—9月份属于高富营养化状态,10—12月份属于富营养化状态,其中溶解无机氮(DIN)全年平均为(0.91±0.11)mg/L,属劣Ⅳ类海水水质标准;溶解无机磷(DIP)全年平均为(0.031±0.005)mg/L,属Ⅲ类海水水质标准;根据有机污染指数(A)显示,2015年该围隔海域2—7月份开始受到有机污染,8月、9月和12月属于轻度有机污染,10月和11月属于中度有机污染。底栖浒苔类的优势种为曲浒苔(Ulva flexuosa),占底栖藻场总生物量的97.3%。2015年3月至12月碧海金沙围隔海域底栖曲浒苔全年总生物量净增长量为1 497.3 t,实验测得曲浒苔组织内总氮(TN)和总磷(TP)平均含量分别为3.50%±0.02%和0.13%±0.01%(干重),全年吸收水体中氮和磷量分别为(4 354.90±46.78)kg和(161.75±1.74)kg。分析表明,碧海金沙围隔海域天然曲浒苔种群通过同化养殖水体中氮磷,具备一定的水质修复能力,但尚未平衡由水产养殖活动造成的营养负荷。因此,在近岸海水养殖海域,除需进行底栖海藻场的构建外,还需要调整养殖结构,如增加大型海藻栽培以建立多营养层次的综合养殖模式(IMTA),实现近岸海水养殖产业的可持续发展。     

典型草原封育过程中植物凋落物的变化动态

以内蒙古巴林右旗退化草原为研究对象,采用直接收集的方法,研究各种围封条件下,退化草原在自然演替过程中土壤凋落物的变化动态。结果表明：典型草原在封育演替过程中,凋落物呈增加的趋势,以封育10年的凋落物量最高;凋落物的养分,不同年限之间均存在显著差异,其中碳素含量以封育1年的最高,封育10年的最低,氮素则是以封育4年的含量...     

生态清洁型封闭式循环水养鱼技术研究

从预防病害发生入手,应用沉淀分离、旋流分离和砂滤等固液分离技术,提高循环水量,增加固液分离、生物过滤、紫外线消毒等水质净化频次,保持鱼类、水质环境和病原微生物的生态平衡,以生态清洁的方式健康养殖。结果表明,在生态清洁型循环水系统中养殖点带石斑鱼,养殖期12个月,无明显病害发生,养殖过程不用药,养殖产量为25.44 kg/m2,成活率87.42%。     

基于空间啮合理论的摆线钢球行星传动根切研究

介绍了摆线钢球行星传动的结构组成和传动原理,提出了利用锥形铣刀包络内、外摆线封闭槽的数学模型,建立了摆线槽齿面的包络面方程。根据空间啮合理论推导出摆线槽齿面的根切界限函数,分析了根切界限函数随基本设计参数的变化规律。结果表明,随着基本设计参数的变化,内、外摆线封闭槽齿面会按一定的先后顺序发生根切,并且总是内摆线槽内侧齿面最先根切,从而得到了不发生根切必须满足的不等式方程,并通过具体实例及计算机图形仿真进行验证。本研究为摆线钢球行星传动的设计制造提供了理论依据。     

小型封闭景观水体应急修复技术研究

良好的感官性状是景观水体的基本特征,封闭景观水体的水域面积小、环境容量低、水体自净能力差等特点决定了其易受到污染.目前针对该水体修复常用的技术手段多为换水及固定底泥.以师陶园内500 m2的封闭池塘为研究对象,对该水体实施换水及固定底泥的应急修复工程,通过监测修复前后的水质,分析其变化情况,评估该应急修复方法的经济性及持效性.结果发现修复10 d后,其水质得到明显改善,水质指标达GB38382-2002Ⅳ类标准,表观污染等级由重污染转变为清洁,氨氮、磷酸盐、COD以及浊度由25、1.5、120、90 mg/L下降到2、0.1、40、5 mg/L,DO由0.5 mg/L上升到3.0 mg/L.该修复工程的费用为2.12元/m3,水质持效时间可达10个月左右.     

Micromorphology of abnormal and decayed xylem in rubberwood canker

Typical symptoms of rubberwood canker found in East Kalimantan, Indonesia, differ from those of conventional rubberwood peach canker. Rubberwood canker showed a conspicuous longitudinal canker with exposed xylem that was discolored and decayed. Bark wounds, resulting from regular tapping, were enclosed within the xylem, and the tissues had become integrated. The characteristics of abnormal and decayed xylem in this rubberwood canker were analyzed by light microscopy and scanning electron microscopy. Xylem in the vicinity of the enclosed bark contained fewer vessels of smaller diameter and shorter length, and significantly wider rays compared with normal xylem. Around the wide growth zones of the canker, axial cells were disoriented and warped toward the canker zones. In view of the separation among cells, and the concentric degradation of the cell walls starting from the lumen surfaces, decayed xylem appeared to be caused mainly by white-rot fungal attack.