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991.
大亚湾大鹏澳网箱养殖水域的浮游植物生态特征研究 总被引:4,自引:3,他引:1
采用现场采样及观察、计数、分析等方法,对大亚湾大鹏澳网箱养殖区及附近海域浮游植物生态特征进行研究。结果显示,养殖区与对照区种类组成基本一致,优势种发生一定变化,主要优势种为菱形海线藻、伏氏海毛藻、细弱海链藻、中肋骨条藻、尖刺菱形藻等。养殖区及附近水域浮游植物栖息密度范围为6.2 ̄2010×104·m-3,平均235.2×104·m-3,养殖区与对照区平均密度分别为141.8和328.6×104·m-3。比较显示,密度均值除冬季养殖区约低于后者2.4倍外,其他季节2个区域基本接近,差异不明显。多样性指数在0.97 ̄4.08范围内变化,养殖区和对照区四季均值分别为3.12和3.15,两者差异不明显。种类组成均匀度变化范围为0.19 ̄0.94,养殖区与对照区无明显差异。多样性阈值在0.23 ̄3.64范围变化,多样性处于Ⅱ ̄Ⅳ级,即多样性差 ̄多样性非常丰富水平,养殖区和对照区均值分别为2.22和2.20,平均处于Ⅲ级,即多样性较好水平。季节变化均以冬季最低,均值分别为0.79和0.83,夏季最高,均值分别为2.83和3.05。 相似文献
992.
基于环境变化的离合器起步补偿控制 总被引:1,自引:0,他引:1
离合器半接合点位置的判断是车辆自动变速传动控制的关键技术之一。在实现车辆离合器自动起步控制的基础上,着重研究了离合器摩擦盘片磨损、路面条件和车载负荷变化等因素对离合器半接合点位置的影响,建立相应的道路模拟检验工况,并提出相应的自动补偿控制措施。 相似文献
993.
基于MFC实现的小型局域网聊天室 总被引:1,自引:0,他引:1
探讨一种基于MFC的抽象类Socket的局域网通信工具一聊天室的设计与实现方法.通过了解Winsock网络编程的相关技术,利用TCP/IP协议簇与应用层通信的中间软件抽象层Socket接口来实现局域网内两台微机之间的连接.通过异步方式实现服务器/客户端的通信模式,从而达到构造小型的局域网聊天室的目的. 相似文献
994.
随着人们思想观念的解放,试婚、一夜情、包二奶现象屡有发生,由此非婚生子女也成了一个严重的社会问题.国外在非婚生子女的保护上有间接保护立法模式和直接保护立法模式.我国在非婚生子女的保护上虽然也有相关规定,但没有相应的具体措施可执行,以致非婚生子女的权益难以得到保护,我国有必要借鉴外国有益的立法模式,从实质上保护非婚生子女的权利. 相似文献
995.
Dong Gyu Choi Ming He Hua Fang Xin Lan Wang Xiao Qin Li Xiang Jun Leng 《Aquaculture Nutrition》2020,26(1):37-46
The present study investigated the effect of fish meal (FM) replacement with fermented soybean meal (FSM) on growth and feed utilization of rainbow trout. Two FSM products, FSM1 (more fermentation with more small peptide and acid than FSM2) and FSM2 were used to replace 20%, 40% and 60% of FM in control diet (250 g/kg FM), respectively (FSM1‐20, FSM1‐40, FSM1‐60, FSM2‐20, FSM2‐40 and FSM2‐60). Then the seven diets were fed to rainbow trout (18.1 g) for 8 weeks. Weight gain (WG), feed conversion ratio (FCR) and digestibility of crude protein and dry matter showed no significant difference among the groups of FSM1‐20, FSM1‐40, FSM2‐20, FSM2‐40 and the control, but WG significantly decreased and FCR increased when 60% FM was replaced by both FSMs (p < .05). The replacement of 40%, 60% FM resulted in lower villus height than the control (p < .05), and intestinal protease activity was lower in FSM2‐40, FSM2‐60 and FSM1‐60 groups than the control group (p < .05). In addition, the activity of alkaline phosphatase and superoxide dismutase increased with increasing levels of FSM (p < .05). In conclusion, dietary fish meal could be replaced by 40% with both FSMs without adverse effects on growth and feed utilization of rainbow trout based on an eight weeks feeding trial. 相似文献
996.
Gang Luo Xiaojin Xu Lingmin Zhao Yingxue Qin Lixing Huang Yongquan Su Qingpi Yan 《Journal of fish diseases》2019,42(7):991-1000
Interaction between bacterial pathogen and aquatic animal host is exceedingly complex, which involves large dynamic changes in gene expression during different stages of the disease. However, research on identifying key virulence genes based on the dynamics of gene expression changes of a one‐sided bacterial pathogen in tissue has not been reported so far across different stages of infectious disease. The clpV for the T6SS of Pseudomonas plecoglossicida was identified for a candidate for key virulence gene based on dynamic changes of gene expression. For the Epinephelus coioides infected using clpV‐RNAi strain, no deaths were observed up to 20 dpi. The spleens, kidneys and livers of all the E. coioides that received clpV‐RNAi strain failed to develop visible nodules at 5–8 dpi, with the swelling gradually disappearing. The burdens of clpV‐RNAi strain in the spleen and blood were greatly reduced at most of the time points after injection, and the burdens of clpV‐RNAi strain in the head kidneys and trunk kidneys also had a sharp reduction from 72 to 120 hpi. This paper provides a new insight into the discovery of key virulence genes of pathogens in infected tissue systems. 相似文献
997.
998.
2011—2012年采用盆栽苗人工接种和田间调查相结合的方法,研究了贡柑产区近年为害严重的黑腐病(病原菌为Alternaria citri)的发生规律。结果表明:在人工接种条件下,其病原菌可以从没有伤口的叶面侵入,但更易从伤口入侵;贡柑和默科特桔最感病,其次是椪柑和南丰蜜桔,在有伤口和连续下雨的条件下马水桔、沙糖桔和温州蜜柑的嫩芽也偶被感染,橙类、柚类、柠檬和金柑抗病。在田间,贡柑、默科特桔最感病,其次是南丰蜜桔、椪柑,马水桔、沙糖桔、温州蜜柑未见发病。刚抽发的嫩梢和幼果易感病,组织越嫩越易感病,老叶、成熟果实感病少,幼树和刚结果树以及嫩梢多的树发病重。该病原菌孢子萌发需要高湿,下雨、高温、高湿有利于该病的发生和流行。夏梢发病最重,其次是春梢和幼果,秋梢发病轻。在人工接种条件下,只要下雨和温度达到15~30℃,1~3天即可显症,病斑沿着叶脉快速扩展。发病快、扩展快是其难防治的最大原因。 相似文献
999.
Color performance of false clownfish, Amphiprion ocellaris Cuvier, was examined under three levels of light intensity (20–50 , 600–850 , and 2700–3500 lx) for 5 wk. The experiment was conducted in nine rectangular glass aquaria (25 × 25 × 20 cm) with three replicates. Each aquarium was stocked with 36 fish, and 3 fish were randomly sampled from each aquarium every other week. Digital images were taken weekly on each individual fish after it was anesthetized in MS‐222. The color performance in hue, saturation, and brightness was quantified using image analysis. In addition to the whole‐body analysis, each fish image was divided into ventral and dorsal parts to assess the body position‐dependent effect. Furthermore, color differences between dorsal fin, anal fin, ventral fin, and caudal fin were also quantified. The whole body was brighter at low light than at medium or at high light intensity. Irrespective of light intensity, the dorsal side was more orange but less bright than the ventral side. Brighter light strengthened overall orange color on fish fins. The dorsal fin and ventral fins appeared more orange than the anal and caudal fins regardless of light intensity and exposure duration. Similar to body color, low light also led to brighter fins, especially for caudal and dorsal fins. Our results indicate that ambient light could regulate fish color performance but could not change the pigment dominance by β‐carotene. Light intensity is unlikely to change the contrast between dorsal and ventral sides, but dim light tends to make fish body brighter, and bright light strengthens orange color on fins. 相似文献
1000.