A study on the meat and bone meal and poultry by-product meal as protein substitutes of fish meal in practical diets for Litopenaeus vannamei juveniles     

Zhu Wei  Mai Kangsen  Zhang Baigang  Wang Fuzhen  Yu Yu 《中国海洋大学学报(英文版)》2004,3(2):157-160

A study was conducted to evaluate the effects of meat and bone meal (MBM) and poultry by-product meal (PBM) as the replacement of fish meal in the diets on the growth performance, survival and apparent digestibility coefficients (ADC) of Litopenaeus vannamei. The basal diets were formulated with 22% fish meal and other ingredients which provided about 40% protein and 9% lipid in the diet. The experimental diets included MBM or PBM to replace 0, 20%, 40%, 60% and 80% of total fish meal respectively. All diets were iso-nitrogenous and isocaloric in gross terms. The results showed that there were no significant differences (Pτ;0.05) in growth performance and ADC among the treatments fed with the diets in which 0–60% fish meal had been replaced with MBM, while the percent weight gain (WG, %), body length gain (BLG, %) and ADC significantly decreased when the MBM was up to 80% of the fish meal. There were no significant differences (Pτ;0.05) in growth performance and ADC among all the treatments fed with the diets in which 0–80% fish meal had been replaced with PBM.  相似文献   

基于ConvLSTM的广西短临降水预报     

黄启桥  麦雄发  李玲  唐菁  唐飞笼 《气象研究与应用》2021,42(4):44-49

针对传统雷达回波外推算法在快速增长或消散降水过程预报精度较低的问题,利用华南雷达回波拼图资料数据,建立ConvLSTM回波外推模型,对广西区域范围进行短临降水预报研究.采用气象业务中的正确率(POD)、临界成功指数(CSI)及误报率(FAR)评判标准检验预报模型,并将ConvLSTM与光流法的预报结果进行对比分析.结果 表明,ConvLSTM模型的CSI、POD分别比光流法提高0.06和0.059,而FAR下降了0.058.ConvLSTM方法比光流法的回波外推预报准确率高,该方法可为广西短临降水预报提供新的参考.  相似文献   

南海北部大陆架莺琼盆地新生代海平面变化   总被引：4，自引：0，他引：4  

谢金有  祝幼华  李绪深  麦文  赵鹏肖 《海相油气地质》2012,17(1):49-58

南海北部大陆架莺琼盆地是建立西太平洋新生代海平面变化的关键地区之一。基于有孔虫和钙质超微化石资料所建立的莺歌海盆地和琼东南盆地新生代相对分辨率较高的年代地层格架,通过南海海域表层建立的浮游有孔虫含量与水深的定量关系,辅以古生态、成因相及特征沉积构造分析和反射地震剖面的海岸上超分析,编制了海平面变化曲线。识别出包含三个完整二级海平面变化旋回和半周期的海平面上升旋回。海平面变化幅度在0～200 m之间。海水最深的时期在早中新世晚期至中中新世早期以及上新世早期,与Haq曲线较为吻合。  相似文献   

Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) in riverine and estuarine sediments of the Pearl River Delta in southern China, with emphasis on spatial variability in diastereoisomer- and enantiomer-specific distribution of HBCD   总被引：4，自引：0，他引：4  

Feng AH  Chen SJ  Chen MY  He MJ  Luo XJ  Mai BX 《Marine pollution bulletin》2012,64(5):919-925

Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) were measured in surface sediments in the Pearl River Delta, southern China. The concentrations ranged from 0.06 to 304 ng/g dry weight for TBBPA and from 0.03 to 31.6 ng/g for total HBCD. The correlations between the TBBPA and HBCD concentrations were significant in rivers (Dongjiang, Zhujiang, Beijiang, and Dayanhe Rivers) with local input sources but not significant in the Xijiang River and Pearl River Estuary without local sources. HBCD was dominated by γ-HBCD (averaged 52.5-75.0%), whereas α-HBCD contributions were relatively high in sediments from the urban areas. The enantiomeric fractions of γ-HBCD in the sediments (averaged from 0.431 ± 0.035 to 0.479 ± 0.010) differed significantly from that in HBCD technical product except for samples from the e-waste area (Dayanhe River, 0.488 ± 0.091). This suggests that enantioselective biotransformation of HBCD occurs in the aquatic environment in this region.  相似文献   

TAT improves in vitro transportation of fortilin through midgut and into hemocytes of white shrimp Litopenaeus vannamei     

Yi Zhou  Wenbing Zhang  Kangsen Mai  Wei Xu  Yanjiao Zhang  Qinghui Ai  Xiaojie Wang 《中国海洋大学学报(英文版)》2012,11(2):197-204

  相似文献   

Route height connection across the sea by using the vertical deflections and ellipsoidal height data     

郭金运  陈永宁  刘新  钟世霞  麦照秋 《中国海洋工程》2013,27(1):99-110

Distance between the main land and island is so long that it is very difficult to precisely connect the height datum across the sea with the traditional method like the trigonometric leveling,or it is very expensive and takes long time to implement the height transfer with the geopotential technique.We combine the data of GPS surveying,astro-geodesy and EGM2008 to precisely connect the orthometric height across the sea with the improved astronomical leveling method in the paper.The Qiongzhou Strait is selected as the test area for the height connection over the sea.We precisely determine the geodetic latitudes,longitudes,heights and deflections of the vertical for four points on both sides across the strait.Modeled deflections of the vertical along the height connecting routes over the sea are determined with EGM2008 model based on the geodetic positions and heights of the sea segmentation points from DNSC08MSS model.Differences of the measured and modeled deflections of the vertical are calculated at four points on both sides and linearly change along the route.So the deflections of the vertical along the route over the sea can be improved by the linear interpolation model.The results are also in accord with those of trigonometirc levelings.The practical case shows that we can precisely connect the orthometric height across the Qiongzhou Strait to satisfy the requirement of order 3 leveling network of China.The method is very efficient to precisely connect the height datum across the sea along the route up to 80 km.  相似文献   

Biological risk and pollution history of polycyclic aromatic hydrocarbons (PAHs) in Nansha mangrove,South China     

Qihang Wu  Jonathan Y.S. Leung  Nora F.Y. Tam  Shejun Chen  Bixian Mai  Xizhen Zhou  Lihua Xia  Xinhua Geng 《Marine pollution bulletin》2014

Chinese government has taken various measures to alleviate pollution caused by polycyclic aromatic hydrocarbons (PAHs) in the region of Pearl River Delta since the economic reform in 1978, but the effectiveness of these measures remains largely unknown. This study aimed to elucidate the biological risk and pollution history of PAHs by measuring the concentrations of 28 PAHs in the surface and core sediments, respectively, in Nansha mangrove. Results found that the biological risk of PAHs was low without obvious spatial variation. The PAH concentration along the depth gradient indicated that PAH pollution was stabilized since the early 1990s while the source of PAHs has gradually changed from combustion of coal to petroleum products. This implied that the mitigation measures taken by the Chinese government were effective. Compared to marine bottom sediment, we propose that using mangrove sediment can provide a more accurate and precise estimate of pollution history of PAHs.  相似文献   

An Application of the Multi-Physics Ensemble Kalman Filter to Typhoon Forecast     

Chanh Kieu  Pham Thi Minh  Hoang Thi Mai 《Pure and Applied Geophysics》2014,171(7):1473-1497

This study examines the roles of the multi-physics approach in accounting for model errors for typhoon forecasts with the local ensemble transform Kalman filter (LETKF). Experiments with forecasts of Typhoon Conson (2010) using the weather research and forecasting (WRF) model show that use of the WRF’s multiple physical parameterization schemes to represent the model uncertainties can help the LETKF provide better forecasts of Typhoon Conson in terms of the forecast errors, the ensemble spread, the root mean square errors, the cross-correlation between mass and wind field as well as the coherent structure of the ensemble spread along the storm center. Sensitivity experiments with the WRF model show that the optimum number of the multi-physics ensemble is roughly equal to the number of combinations of different physics schemes assigned in the multi-physics ensemble. Additional idealized experiments with the Lorenz 40-variable model to isolate the dual roles of the multi-physics ensemble in correcting model errors and expanding the local ensemble space show that the multi-physics approach appears to be more essential in augmenting the local rank representation of the LETKF algorithm rather than directly accounting for model errors during the early cycles. The results in this study suggest that the multi-physics approach is a good option for short-range forecast applications with full physics models in which the spinup of the ensemble Kalman filter may take too long for the ensemble spread to capture efficiently model errors and cross-correlations among model variables.  相似文献   

Features of the Distribution of Abnormal Gasgeochemical Fields in the Red River Rift (Gulf of Tonkin,South China Sea)     

Shakirov  R. B.  Hung  Duong Quoc  Syrbu  N. S.  Anh  Le Duc  Obzhirov  A. I.  Borzova  O. V.  Okulov  A. K.  Van Nam  Bui  Van Diep  Nguyen  Dong  Mai Duc  Legkodimov  A. A.  Shakirova  M. V.  Ponomareva  A. L.  Bakunina  M. S. 《Doklady Earth Sciences》2019,484(2):181-184

Doklady Earth Sciences - This paper reports the results of the third Russian–Vietnamese expedition (V.I. Il'ichev Pacific Oceanological Institute, Far East Branch, Russian Academy of...  相似文献   

东南亚断裂构造的演化     

高庭朝  阮友宣  黎文勇  范南雄  Mai Xuan Bach  Thai Anh Tuan 《大地测量与地球动力学》2005,25(1):51-60

本研究项目是采用诸如地质学解释、影像判读和地球物理探测等多种方法相结合进行的。在所得结果的基础上参考了越南国内外同行的一些资料编制了东南亚、越南及邻区的断裂构造图．其比例尺分别为1：4百万和1：1百万。分析所得结果显示出东南亚断裂构造演化的下列情况：1)在现今地质结构方面东南亚是欧亚岩石圈板块的东南部分．由一条消减带围绕．这条消减带的伸展从Myanmer开始,通过Nicobar,Java Timor直到东菲律宾。东南亚被Song Hong(即红河)断裂,Three Pagodas断裂和Hainam-Natuna断裂等2级断裂系统分成3个微板块。2)在早新生代．东南亚是分为5个微板块的。它们的分界断裂中有2个一级断裂(中央东海扩张带和Lupar-Kuching消减带)和3个二级断裂(即上述3个)。3)上述绝大多数二和三级断裂从晚新生代起活化且继承了从早新生代即已发生和发展了的二、三级断裂,但在某些条件下．运动方向却完全变成了相反,尤其是走滑运动的方向。我们的研究结果表明：在这一地区内,盆地、隆起、岩浆侵入、褶皱和局部断裂等构造的形成都取决于这些沿着一、二级走滑断裂的微板块运动。  相似文献