Shepherd＇s purse seeds were collected from winter wheat fields and road sides in Hebei Province,China.Their sensitivities to tribenuron-methyl were evaluated in a whole plant dose response assay in the greenhouse.Res...Shepherd＇s purse seeds were collected from winter wheat fields and road sides in Hebei Province,China.Their sensitivities to tribenuron-methyl were evaluated in a whole plant dose response assay in the greenhouse.Results revealed that HB-1,HB-2,HB-3,HB-4,HB-6,HB-7,HB-17,HB-18,HB-19,HB-20,HB-21,and HB-22 populations were susceptible to tribenuron-methyl characterised by very low GR50 values of about 0.10 g a.i.ha-1.On the other hand,populations HB-15 and HB-16 had moderate resistance to tribenuron-methyl with resistance indices （RI） ranging from 10-100 folds,whilst populations HB-5,HB-8,HB-9,HB-10,HB-11,HB-12,HB-13,and HB-14 expressed high level of resistance to tribenuron-methyl with resistance indices over 100.The proportion of moderate resistance level was about 9.09%,and that of high resistance was about 36.36%.展开更多
This study applies the mass-spring system to model the dynamic behavior of a submerged net panel similar to the shooting process in actual purse seine fishing operation. Modeling indicates that there is insufficient s...This study applies the mass-spring system to model the dynamic behavior of a submerged net panel similar to the shooting process in actual purse seine fishing operation. Modeling indicates that there is insufficient stretching with the net panel under the floatline in the prophase of the shooting process. Sinkers at different locations along the leadline descend successively after submergence, and the sinking speed decreases gradually with elapsed time until attainment of a stable state. Designs with different current speeds and sinker weights are executed to determine the dimensional shape and sinking characteristics of the net. The net rigged with greater sinker weight gains significantly greater sinking depth without water flow. Compared with the vertical spread of the net wall in static water, the middle part of the netting presents a larger displacement along the direction of current under flow condition. It follows that considerable deformation of the netting occurs with higher current speed as the sinkers affected by hydrodynamic force drift in the direction of current. The numerical model is verified by a comparison between simulated results and sea measurements. The calculated values generally coincide with the observed ones, with the former being slightly higher than the latter. This study provides an implicit algorithm which saves computational loads for enormous systems such as purse seines, and ensures the accuracy and stability of numerical solutions in a repetitious iteration process.展开更多
In the Indian Ocean, bigeye tuna supports one of the most important fisheries in the world. This fishery mainly consists of two components: longline and purse seine fisheries. Evidence of overfishing and stock depleti...In the Indian Ocean, bigeye tuna supports one of the most important fisheries in the world. This fishery mainly consists of two components: longline and purse seine fisheries. Evidence of overfishing and stock depletion of bigeye tuna calls for an evaluation of alternative management strategies. Using an age-structured operating model, parameterize dwith the results derived in a recent stock assessment,we evaluated the effectiveness of applying constant fishing mortality (CF) and quasi-constant fishing mortality (QCF) strategies to reduce fishing effort of purse seining with fish aggregating devices (FADs) at different rates. Three different levels of productivity accounted for the uncertainty in our understanding of stock productivity. The study shows that the results of CF and QCF are similar. Average SSB and catchduring simulation years would be higher if fishing mortality of FAD-associated purse seiningwas reduced rapidly. The banning or rapid reduction of purse seining with FAD resulted in a mean catch, and catch in the last simulation year, higher than that of the base case in which no change was made to the purse seine fishery. This could be caused by growth overfishing by purse seine fisheries with FADs according to the per-recruit analysis. These differences would be more obvious when stock productivity was low. Transferring efforts of FAD-associated purse seining to longline fisheries is also not feasible.Our study suggests that changes are necessary to improve the performance of the current management strategy.展开更多
EVER since Yang Yue got married six years ago, she has kept her husband, Liang Xiaoming, on a short financial leash, giving him about 2,500 yuan （$393） a month for his own personal use.
The Double Take column looks at a single topic from an African and Chinese perspective. This month we discuss whether husbands should surrender their salary within a family or not.
海山是海底重要的生物栖息地类型之一,是研究海洋生物多样性的热点区域。黄鳍金枪鱼(Thunnus albacares)广泛分布于中西太平洋,具有极高的生态和经济价值,然而,鲜有关于海山及其相关特征对黄鳍金枪鱼资源丰度和分布影响的研究。基于2010...海山是海底重要的生物栖息地类型之一,是研究海洋生物多样性的热点区域。黄鳍金枪鱼(Thunnus albacares)广泛分布于中西太平洋,具有极高的生态和经济价值,然而,鲜有关于海山及其相关特征对黄鳍金枪鱼资源丰度和分布影响的研究。基于2010—2021年中西太平洋渔业委员会(Western and Central Pacific Fisheries Commission,WCPFC)汇总的延绳钓和围网渔业数据结合海山特征数据,采用广义加性模型(Generalized additive model,GAM)分析两种不同捕捞方式的黄鳍金枪鱼单位捕捞努力量渔获量(Catch per unit effort,CPUE)与海山相关特征之间的关系。结果表明,中西太平洋两种渔业方式的黄鳍金枪鱼渔获量主要来源于海山区域,海山特征对两种渔业黄鳍金枪鱼的CPUE均产生了极显著性影响(P<0.001)。在延绳钓渔业中,较高的CPUE出现在山顶深度、粗糙度、底面积和海山密度较小、坡度较缓的区域;而在围网渔业中,较高的CPUE则出现在粗糙度较小、山顶深度较大、底面积较大、较陡峭且密集的海山区域。研究探讨了中西太平洋海山特征对黄鳍金枪鱼不同群体的影响机制,为今后进一步探索黄鳍金枪鱼种群分布和资源丰度变化与海洋环境的关系提供了参考与新思路。展开更多
目的:利用生物电阻抗成像(EIT)技术探究不同自主呼吸训练方法对区域性肺通气的影响,以期为慢性阻塞性肺疾病(COPD)患者在训练标准及方法选取上提供行之有效的康复指导方案。方法:共纳入28名健康志愿者,取舒适站立位并进行:(1)平静呼吸;...目的:利用生物电阻抗成像(EIT)技术探究不同自主呼吸训练方法对区域性肺通气的影响,以期为慢性阻塞性肺疾病(COPD)患者在训练标准及方法选取上提供行之有效的康复指导方案。方法:共纳入28名健康志愿者,取舒适站立位并进行:(1)平静呼吸;(2)腹式呼吸;(3)缩唇呼吸;(4)腹式缩唇呼吸,每位被试的四种呼吸方式随机决定,整个过程中连续记录胸部EIT;分别对比四种呼吸方式期间的潮气量(TV)、呼气末肺阻抗(EELI)、通气中心(center of ventilation,Co V)、不均一指数(GI)、区域通气延迟(RVD)。结果:较平静呼吸,腹式呼吸、缩唇呼吸及腹式缩唇呼吸三种呼吸训练方法期间的TV明显增大(P<0.05);EELI明显降低(P<0.05);Co V明显减小(P<0.05,腹侧通气增多);腹式呼吸和腹式缩唇呼吸的GI明显减小(P<0.05,通气更均匀);缩唇呼吸和腹式缩唇呼吸RVD明显增加(P<0.05)。结论:腹式呼吸、缩唇呼吸、腹式缩唇呼三种呼吸训练方法均能有效增加肺通气量,减少肺功能残气量,但三种呼吸训练方法对肺通气的影响各不相同:缩唇呼吸通气向腹侧移动更显著(COV更小),区域通气延迟更显著(RVD更大),而腹式呼吸可改善通气均匀性(GI更小)。因此,从区域性肺通气的角度,建议COPD患者在进行呼吸训练时应腹式呼吸与缩唇呼吸独立交替进行,以达到更好的呼吸训练效果。展开更多
基金supported by the State Key Laboratory for Biology of Plant Diseases and Insect Pests,Institute of Plant Protection (IPP),Chinese Academy of Agricultural Sciences,China (SKL2010OP15)the National Natural Science Foundation of China (31000856)
文摘Shepherd＇s purse seeds were collected from winter wheat fields and road sides in Hebei Province,China.Their sensitivities to tribenuron-methyl were evaluated in a whole plant dose response assay in the greenhouse.Results revealed that HB-1,HB-2,HB-3,HB-4,HB-6,HB-7,HB-17,HB-18,HB-19,HB-20,HB-21,and HB-22 populations were susceptible to tribenuron-methyl characterised by very low GR50 values of about 0.10 g a.i.ha-1.On the other hand,populations HB-15 and HB-16 had moderate resistance to tribenuron-methyl with resistance indices （RI） ranging from 10-100 folds,whilst populations HB-5,HB-8,HB-9,HB-10,HB-11,HB-12,HB-13,and HB-14 expressed high level of resistance to tribenuron-methyl with resistance indices over 100.The proportion of moderate resistance level was about 9.09%,and that of high resistance was about 36.36%.
基金financially supported by the National High Technology Research and Development Program of China (No. 2012AA092302)the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20103104120006)the Project of First-class Disciplines Shanghai Universities: Eco-Friendly Fishing Gear and Fishing Methods in the Field of Fisheries Science (B-5005-12-0001-4C)
文摘This study applies the mass-spring system to model the dynamic behavior of a submerged net panel similar to the shooting process in actual purse seine fishing operation. Modeling indicates that there is insufficient stretching with the net panel under the floatline in the prophase of the shooting process. Sinkers at different locations along the leadline descend successively after submergence, and the sinking speed decreases gradually with elapsed time until attainment of a stable state. Designs with different current speeds and sinker weights are executed to determine the dimensional shape and sinking characteristics of the net. The net rigged with greater sinker weight gains significantly greater sinking depth without water flow. Compared with the vertical spread of the net wall in static water, the middle part of the netting presents a larger displacement along the direction of current under flow condition. It follows that considerable deformation of the netting occurs with higher current speed as the sinkers affected by hydrodynamic force drift in the direction of current. The numerical model is verified by a comparison between simulated results and sea measurements. The calculated values generally coincide with the observed ones, with the former being slightly higher than the latter. This study provides an implicit algorithm which saves computational loads for enormous systems such as purse seines, and ensures the accuracy and stability of numerical solutions in a repetitious iteration process.
基金Supported by the Shanghai Ocean University Graduate School (PhD Dissertation Grant)the Project of Shanghai Science and Technology Innovation(No.12231203900)+4 种基金the National Natural Science Foundation of China(No.NSFC41276156)the Industrialization Program of the National Development and Reform Commission(No.2159999)the Shanghai Leading Academic Discipline Projectthe National Distant-water Fisheries Engineering Research Center,the Scientific Observing and Experimental Station of Oceanic Fishery Resources,Ministry of Agriculture,China.Y.supported by the Shanghai Leading Teacher Program
文摘In the Indian Ocean, bigeye tuna supports one of the most important fisheries in the world. This fishery mainly consists of two components: longline and purse seine fisheries. Evidence of overfishing and stock depletion of bigeye tuna calls for an evaluation of alternative management strategies. Using an age-structured operating model, parameterize dwith the results derived in a recent stock assessment,we evaluated the effectiveness of applying constant fishing mortality (CF) and quasi-constant fishing mortality (QCF) strategies to reduce fishing effort of purse seining with fish aggregating devices (FADs) at different rates. Three different levels of productivity accounted for the uncertainty in our understanding of stock productivity. The study shows that the results of CF and QCF are similar. Average SSB and catchduring simulation years would be higher if fishing mortality of FAD-associated purse seiningwas reduced rapidly. The banning or rapid reduction of purse seining with FAD resulted in a mean catch, and catch in the last simulation year, higher than that of the base case in which no change was made to the purse seine fishery. This could be caused by growth overfishing by purse seine fisheries with FADs according to the per-recruit analysis. These differences would be more obvious when stock productivity was low. Transferring efforts of FAD-associated purse seining to longline fisheries is also not feasible.Our study suggests that changes are necessary to improve the performance of the current management strategy.
文摘EVER since Yang Yue got married six years ago, she has kept her husband, Liang Xiaoming, on a short financial leash, giving him about 2,500 yuan （$393） a month for his own personal use.
文摘The Double Take column looks at a single topic from an African and Chinese perspective. This month we discuss whether husbands should surrender their salary within a family or not.
文摘海山是海底重要的生物栖息地类型之一,是研究海洋生物多样性的热点区域。黄鳍金枪鱼(Thunnus albacares)广泛分布于中西太平洋,具有极高的生态和经济价值,然而,鲜有关于海山及其相关特征对黄鳍金枪鱼资源丰度和分布影响的研究。基于2010—2021年中西太平洋渔业委员会(Western and Central Pacific Fisheries Commission,WCPFC)汇总的延绳钓和围网渔业数据结合海山特征数据,采用广义加性模型(Generalized additive model,GAM)分析两种不同捕捞方式的黄鳍金枪鱼单位捕捞努力量渔获量(Catch per unit effort,CPUE)与海山相关特征之间的关系。结果表明,中西太平洋两种渔业方式的黄鳍金枪鱼渔获量主要来源于海山区域,海山特征对两种渔业黄鳍金枪鱼的CPUE均产生了极显著性影响(P<0.001)。在延绳钓渔业中,较高的CPUE出现在山顶深度、粗糙度、底面积和海山密度较小、坡度较缓的区域;而在围网渔业中,较高的CPUE则出现在粗糙度较小、山顶深度较大、底面积较大、较陡峭且密集的海山区域。研究探讨了中西太平洋海山特征对黄鳍金枪鱼不同群体的影响机制,为今后进一步探索黄鳍金枪鱼种群分布和资源丰度变化与海洋环境的关系提供了参考与新思路。
文摘目的:利用生物电阻抗成像(EIT)技术探究不同自主呼吸训练方法对区域性肺通气的影响,以期为慢性阻塞性肺疾病(COPD)患者在训练标准及方法选取上提供行之有效的康复指导方案。方法:共纳入28名健康志愿者,取舒适站立位并进行:(1)平静呼吸;(2)腹式呼吸;(3)缩唇呼吸;(4)腹式缩唇呼吸,每位被试的四种呼吸方式随机决定,整个过程中连续记录胸部EIT;分别对比四种呼吸方式期间的潮气量(TV)、呼气末肺阻抗(EELI)、通气中心(center of ventilation,Co V)、不均一指数(GI)、区域通气延迟(RVD)。结果:较平静呼吸,腹式呼吸、缩唇呼吸及腹式缩唇呼吸三种呼吸训练方法期间的TV明显增大(P<0.05);EELI明显降低(P<0.05);Co V明显减小(P<0.05,腹侧通气增多);腹式呼吸和腹式缩唇呼吸的GI明显减小(P<0.05,通气更均匀);缩唇呼吸和腹式缩唇呼吸RVD明显增加(P<0.05)。结论:腹式呼吸、缩唇呼吸、腹式缩唇呼三种呼吸训练方法均能有效增加肺通气量,减少肺功能残气量,但三种呼吸训练方法对肺通气的影响各不相同:缩唇呼吸通气向腹侧移动更显著(COV更小),区域通气延迟更显著(RVD更大),而腹式呼吸可改善通气均匀性(GI更小)。因此,从区域性肺通气的角度,建议COPD患者在进行呼吸训练时应腹式呼吸与缩唇呼吸独立交替进行,以达到更好的呼吸训练效果。
