Experimental Analysis of Construction Time Space Effect for Large Span and Flat Multi Arch Tunnel

For the large span and flat, together with the interaction effect of construction and disturbance of surrounding rock, the mechanical of large span and flat multi arch tunnel is very complicated, and the time space effect is different from that of two lane multi arch tunnel or separated tunnel. Adopting the “CTSSSRH”, the 3 D dynamic process of the tunnel construction was simulated. Analyzing the rule of surrounding rock displacement and stress with excavation, the time space effect of large span and flat multi arch tunnel was proposed.     

无子沙糖橘(十月橘)的选育

采用芽变选种的方法,在四会市石狗镇选出了无子柑橘新品种—无子沙糖橘(十月橘)。果略小,单果重平均40g左右,单果平均种子数0.5粒以内,达到柑橘无子的标准。果实扁平,皮橘红色,薄而脆;果肉橙黄色,味清甜,可溶性固形物13%以上,肉质爽脆化渣,品质上等。早结丰产性好,发梢能力强,3月上中旬开花,12月上旬果实开始成熟。     

四会市低温与霜冻气候变化特征分析

利用1961—2010年四会市气象观测站50年逐日观测资料,对四会市出现低温和霜冻的日数、年、月变化及其强度、初、终日期进行统计分析,并对出现低温、霜冻天气的前期气象要素的变化进行浅析,找出单站气象要素与出现低温、霜冻天气之间的联系。     

Tench farming in China: present status and future prospects

Tench, Tinca tinca (L.) was introduced as a new species to Chinese aquaculture in 1998. Biological characteristics of tench are studied, and propagation techniques are improved at the Hubei Province Fisheries Institute with co-operation with the Research Institute of Fish Culture and Hydrobiology in Czech Republic and Institute of Hydrobiology, Chinese Academy of Sciences. The first successful artificial propagation of tench in China was made in 2000. The number of produced tench larvae increased from 5 millions in 2001 to 20 millions in 2002, and to 200 millions in 2003. The number of juveniles >5 cm reached 12 millions in 2002 and 120 millions in 2003. Total area of ponds with tench culture was 1400 ha in 2002 and 5400 ha in 2003. Main problems that hinder development of tench culture in China are identified, and future prospects of tench farming in China are highlighted. Abundant water bodies for aquaculture and cheap man-power make the export of tench from China to Europe, USA, Australia and Korea a promising activity.     

休闲农业发展模式探讨

作为当今农业转型和旅游业发展的新走向,休闲农业的发展是在国外起步较早。基于比较国内外休闲农业的主要开发模式,文章总结和借鉴了国外成功经验,从依托于资源环境状况进行定位（资源角度）、立足于需求导向考虑发展模式（客源角度）以及着眼于休闲农业综合系统完善（环境协调角度）三个方面．提出在打造国际旅游岛的大背景下。海南发展休闲农业的几点建议。     

特效植物营养素对柑桔产量品质及表观遗传的影响

以柑桔4个品种为材料,采用特效植物营养素(SPNE)在果实发育期喷施植株,结果表明SPNE能提高柑桔不同品种的产量和品质,经SPNE处理的柑桔种子能产生超过对照种子的表观遗传效应,表现为种子发芽成苗率以及幼苗株重、株高、叶面积、根长、叶绿素含量超过对照。不同品种用SPNE喷施次数相同,表现效果不同;同一品种用SPNE喷施次数不同,表现的效果也不同,在间隔喷施SPNE 4次的范围内,效果随着喷施次数增加而增大。     

粤西四会防雹作业催化剂常用量的估算

通过计算粤西四会市发生冰雹天气时单位体积冰雹云的冰核播撒量,按照优先、高效的原则合理选择防雹作业工具和催化剂,得出防雹作业时催化剂的需求用量,目的在于以低投入换取高效益。     

配施有机肥对香蕉生长和产量的影响

为了探索用鸡粪作栽培肥料的肥料效果,进行了香蕉配施有机肥(鸡粪)试验。结果表明,用鸡粪栽培香蕉,可以促进香蕉植株的生长,提前抽蕾,提早成熟和提高产量,同时还可以提高香蕉可溶性固形物含量,改善香蕉果形和熟色光泽,提高产品品质和效益。而施用量以鸡粪的纯氮量占总施纯氮的50%为宜,效益最好。     

山羊鼻内肿瘤病毒荧光定量PCR检测方法的建立及应用

为了解山羊鼻内肿瘤病毒(ENTV-2)的流行情况,本研究针对ENTV-2的env基因设计了1对特异性引物与探针,通过RT-PCR条件优化,成功建立了ENTV-2荧光RT-qPCR检测方法。该方法特异性高、灵敏性强(5.61 copies/μL)、重复性好(CV为0.09%~1.20%)。本研究建立的一步法荧光RT-qPCR方法为ENTV-2的临床检测以及流行病学调查提供技术支撑。     

Induced meiotic gynogenesis in tench, Tinca tinca (L.) using irradiated heterogenic sperm

Effects of the starting time and duration of cold shock, as well as the source of heterogenic sperm on the percentage of viable gynogenic larvae (PVGL) in tench were studied. The DNA in sperm of red common carp (Cyprinus carpio var singuonensis) was inactivated by ultraviolet radiation prior to use to induce meiotic gynogenetic development in tench. In experiment 1, tench eggs were cold-shocked for 30 min starting at 1, 3, 5, 7, 10 and 15 min post activation. In experiment 2, cold shock began 5 min after activation and lasted for 10, 20, 30, 40, 50 min, respectively. Each experiment was run in triplicate using 3 tench females, and one group not treated with cold shock was included in each experiment to serve as a control group. In experiment 3, sperm of bigmouth buffalo (Ictiobus cyprinellus), red common carp or grass carp (Ctenopharyngodon idella) was used to induce gynogenesis in tench with a 20-min cold shock starting 5 min post activation. The results showed that PVGL from the control group was very low (0.11–0.47%). In experiment 1, the highest average PVGL (9.60%) was observed when cold shock treatment was applied 5 min post activation. When cold shock treatment was started 5 min post activation, duration of cold shock affected PVGL. Cold shock lasting 20 min resulted in the highest average PVGL (12. 57%) among the selected duration of cold shock studied in experiment 2. The average PVGL was 2.3, 8.6, and 9.3%, respectively, for eggs induced by sperm of bigmouth buffalo, red common carp and grass carp. Average PVGL was significantly lower for eggs induced by sperm of bigmouth buffalo, compared with that for eggs induced by sperm of the other two species. However, average PVGL were similar for eggs induced by sperm of red common carp and grass carp. In summary, the optimal conditions for gynogenesis in tench include the use of irradiated sperm of grass carp to activate the eggs and cold shock of 20 min starting 5 min post activation. Since female tench grow much faster to a larger size than male tench, gynogenesis of tench holds great potential for production enhancement.