Effects of mangrove deforestation on fish assemblage at Pak Phanang Bay,southern Thailand   总被引：2，自引：0，他引：2  

Tatsuya Shinnaka  Mitsuhiko Sano  Kou Ikejima  Prasert Tongnunui  Masahiro Horinouchi  Hisashi Kurokura 《Fisheries Science》2007,73(4):862-870

Daytime sampling using a seine net was conducted at Pak Phanang Bay (Nakhon Si Thammarat Province, Thailand) in February and July 2006, to determine differences in fish assemblage structures between a mangrove site and an adjacent site completely cleared of mangroves. The overall numbers of fish species and individuals were significantly higher at the mangrove site than the cleared site in both months. Although benthic crustacean feeders showed more species and individual numbers at the mangrove site in both months, the opposite was found for zooplankton feeders. A cluster analysis, based on the abundance of each species, demonstrated that the fish assemblage structures were distinctly different between the two sites. In addition, significant differences in length frequency distributions for each of the four most abundant species were found between the sites in February and/or July. Small individuals of Scatophagus argus, Ambassis nalua, and Tetraodon nigroviridis were more common at the mangrove site, and of Chelon subviridis at the cleared site. These results suggest that mangrove deforestation exerts marked effects on fish assemblages.  相似文献   

Light and electron microscopic evidence of white spot disease in the giant tiger shrimp, Penaeus monodon (Fabricius), and the kuruma shrimp, Penaeus japonicus (Bate), cultured in Taiwan   总被引：2，自引：0，他引：2  

C S Wang  K F J Tang  G H Kou  & S N Chen 《Journal of fish diseases》1997,20(5):323-331

Since 1992, mass mortalities among cultured giant tiger shrimp, Penaeus monodon (Fabricius), and kuruma shrimp, Penaeus japonicus (Bate), have been observed in Taiwan. The condition is known as 'white spot disease' (WSD), based on the characteristic white spots on the cuticle of diseased shrimp. With the scanning electron microscope, two sizes of white spots were observed. Each spot represented a protrusion on the inside surface of the carapace. The composition of white spots was similar to that of the cuticule, most calcium, as determined with an energy dispersive spectrometer. Histological studies of moribund, infected specimens revealed degenerated cells, characterized by hypertrophied nuclei, in various meso- and ectodermal tissues. Infected tissues included cuticular epidermis, connective tissue, lymphoid organ, antennal gland, and haematopoietic, gill and nervous tissue. Nuclei were Feulgen-positive and no occlusion body was found in the necrotic tissue. Transmission electron microscopy revealed the presence of rod-shaped and enveloped virions in the hypertrophied nuclei. The virions measured 298 ± 21 × 107 ± 8 nm in the giant tiger shrimp and 248 ± 12 × 104 ± 8 nm in the kuruma shrimp. In an experimental infection trial, cumulative mortality was 40% within 14 days under stress conditions. No mortality was observed in controls or in non-stressed infected shrimp. Experimental infections show that environmental stressors such as ammonia may enhance the severity of WSD virus infections in cultured shrimp.  相似文献   

Antibody response of glass eels,Anguilla japonica Temminck & Schlegel, to Pleistophora anguillarum Hoshina (Microspora) infection     

H-W Hung  C-F Lo  C-C Tseng  & G-H Kou 《Journal of fish diseases》1997,20(3):237-239

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非接触式测温鉴定母猪典型生理状态     

王晨阳  胡冰艳  李雨晴  寇忠云  李爱赟  李倩  庞卫军 《农业工程学报》2022,38(20):149-155

体温是衡量母猪发情与否的关键生理指标。母猪发情期与间情期体温的明显不同,是运用红外热成像监测母猪体温变化以鉴定母猪发情的依据。该研究基于Y3TB01体温筛查智能摄像机和红外热像仪C3实时非接触拍摄母猪红外热图像,并运用图像分析技术获取体温,为非接触式测温用于鉴定母猪典型生理状态提供支持。试验以空怀期、发情期、妊娠1～8 d和妊娠9～16 d大白初产和经产母猪共720头为研究对象,利用红外设备和电子体温计分别测量母猪的眼睛、耳、耳蜗、乳房、外阴、臀部和直肠温度,筛选不同胎次发情母猪和返情母猪的体表关键部位温度,进行差异分析。结果表明：运用Y3TB01体温筛查智能摄像机可以代替直肠温度测定,准确监测母猪体表温度（相关系数为0.973）;红外热像仪C3检测体温异常母猪的体表温度,臀部温度可以作为筛选大白初产发情母猪和返情母猪的测定部位（准确率分别为77%和72%）,外阴温度可以作为筛选大白经产发情母猪和返情母猪的测定部位（准确率分别为88%和81%）。因此,Y3TB01体温筛查智能摄像机和红外热像仪C3配套技术能准确监测母猪体温和异常体温报警,明确不同胎次不同生理时期大白母猪体表部位温度和体温分布,准确鉴定出发情母猪和返情母猪。研究为非接触式测温鉴定母猪发情技术提供了科学依据,对规模化猪场母猪的饲养管理与疫情防控具有重要意义。  相似文献   

利用智能推荐技术改进电子科研档案网络服务质量探讨     

寇玉香 《计算机与农业》2010,(3):98-100

改进电子科研档案网络服务质量的智能推荐方法主要包括关联规则的推荐方法、协作过滤推荐技术和聚类方法的推荐技术三种。这些智能推荐方法在客户浏览、检索和购买电子档案产品过程中,对于评价客户的需求、期望和优秀服务的感知度具有广泛的应用。智能推荐方法可评价客户对电子科研档案网络服务和网络资源的满意度,进而向客户推荐适当的电子产品的手段,必将极大地提高电子科研档案网络服务质量。  相似文献   

麦草酸水解制取糠醛和纸浆的研究   总被引：1，自引：0，他引：1  

吴玉英  张力平  寇顺利  王乃文 《林产工业》2000,27(3):26-28

提出一种采用稀硫酸水解，综合利用麦草、制取糠醛和纸浆的方法。通过对水解反应影响因素的探讨．发现较优 化的水解工艺条件为用酸量20％、时间180min、最高温度110℃、液比15洗浆废水和精馏后废水的污染负荷远低于常规碱法草浆厂废水的污染负荷，且低于GB3544-92规定的造纸工业废水排放二级标准。  相似文献   

烟草高分子量核DNA提取方法比较     

BAC文库  HMW DNA  一次选择法  二次选择法 《勤云标准版测试》2006,(3)

高分子量(HMW)核DNA的制备是构建BAC文库关键环节之一。为构建高质量的烟草BAC文库,作者研究了一次选择法和二次选择法提取烟草高分子量核DNA的效果。研究结果表明:虽然二次选择法得到的高分子量核DNA浓度较低,但此法省略了对细胞核连续3￣5次的漂洗,而且得到含DNA的凝胶块(plugs)数量是用一次选择法的3倍,因此得到高分子量DNA的总量更高;同时二次选择法得到的plugs纯度更高,排除了酶切时细胞杂质对HMWDNA的干扰,此外在节约材料等方面也优于一次选择法。  相似文献   

甘蓝型油菜(Brassica napus L.)千粒重性状遗传体系分析   总被引：8，自引：1，他引：8  

戚存扣  盖钧镒  傅寿仲  浦惠明  张洁夫  陈新军  高建琴 《作物学报》2004,30(12):1274-1277

通过遗传差异较大的2个甘蓝型油菜（Brassica napus L.）纯系亲本组合（HSTC14×宁油7号）衍生后代的世代家系群体分析，应用主基因+多基因家系世代联合分离分析方法研究油菜千粒重的遗传体系。结果表明，甘蓝型油菜HSTC14×宁油7号组合千粒重遗传体系系由一对主基因+多基因构成，主基因中只有加性效应(d = 0.1062),不存在显  相似文献   

内蒙古西部黄土丘陵区土壤水分动态初探   总被引：1，自引：1，他引：1  

寇志强  王其昌 《水土保持通报》1992,12(6):60-63,77

通过对内蒙古西部黄土丘陵区土壤水分的初步研究,表明:该区土壤水分的垂直动态分布分为三个不同层次,即:水分不稳定层(0～40cm);中间过渡层(40～100cm);水分相对稳定层(100～200cm);旱作土壤水分的动态变化与降雨的变化基本一致;作物对土壤水分的消耗主要是当年降雨。  相似文献   

南方红壤区植被覆盖因子估算模型构建与验证   总被引：3，自引：0，他引：3  

黄俊  金平伟  姜学兵  林丽萍  寇馨月  徐舟  刘斌  方宗福 《农业工程学报》2020,36(17):106-114

研究红壤区植被覆盖因子变化规律、构建植被覆盖因子计算模型可为该区域水土流失防治及动态监测提供科学依据。该研究基于广东省五华县水土保持试验推广站200余场降雨试验观测数据,分析了影响水土流失的各关键因子与次降雨土壤侵蚀模数(Individual Rainfall Event Soil Erosion Modulus,ISEM)间定量关系,基于中国土壤流失方程计算了系列次降雨事件不同植被覆盖度对应植被覆盖因子值,构建了植被覆盖因子值与植被覆盖度间数学模型,从点、面2个尺度对模型计算精度进行了验证。结果表明:1)ISEM随植被覆盖度增加而降低;ISEM与雨前土壤表层含水率间存在显著正相关对数关系;ISEM随坡度增加呈先增后减的变化规律;ISEM随次降雨量、次降雨侵蚀力和次降雨径流深呈显著正相关线性变化关系。2)构建了植被覆盖因子值与植被覆盖度间二阶指数衰减模型,该模型决定系数和纳什系数分别达0.947和0.876。点尺度验证结果表明90%样本模型计算值与观测值相对误差均小于0.30;面尺度验证结果表明,70%～80%的植被覆盖因子计算值相对误差不超过0.1。总体而言,该模型计算精度较为理想,但由于研究对象典型的时空尺度特征,仍需要更多观测数据对该模型进行完善和验证。研究成果可为深入理解红壤区土壤侵蚀规律、水土流失动态监测提供有益参考。  相似文献