The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of ...The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of Navier slip conditions on exchange flows within a long channel connecting two large reservoirs of differing salinity.These horizontal density gradients drive the flow.We modify the recent one-dimensional theory,developed to avoid runaway stratification,to account for the presence of uniform slip walls.By adjusting the parameters of the horizontal density gradient based on the slip factor,we resolve analytically various flow regimes ranging from high diffusion to transitional high advection.These regimes are governed by physical parameters like channel aspect ratio,slip factor,Schmidt number,and gravitational Reynolds number.Our solutions align perfectly with ones in the no-slip limit.More importantly,under the conditions of no net flow across the channel and high Schmidt number(where stratification is concentrated near the channel’s mid-layer),we derive a closed-form solution for the slip parameter,aspect ratio,and gravitational Reynolds number that describes the interface’s behavior as a sharp interface separating two distinct zones.This interface,arising from hydrostatic wall gradients,ultimately detaches the low-and high-density regimes throughout the channel when the gravitational Reynolds number is inversely proportional to the aspect ratio for a fixed slip parameter.This phenomenon,observed previously in 2D numerical simulations with no-slip walls in the literature,is thus confirmed by our theoretical results.Our findings further demonstrate that wall slip leads to distinct and diverse flow regimes.展开更多
Sharp eyespot(Rhizoctonia cerealis)is a widespread soil-borne fungal disease that poses a severe threat to wheat health,and it is one of the main obstacles to achieving stable and high-quality wheat yields in China.Ou...Sharp eyespot(Rhizoctonia cerealis)is a widespread soil-borne fungal disease that poses a severe threat to wheat health,and it is one of the main obstacles to achieving stable and high-quality wheat yields in China.Our collaborative team has developed a novel,efficient,and low-toxicity fungicide named Y17991(N-(2-(2,4-bis-(trifluoromethyl)phenoxy)phenyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide).Preliminary laboratory tests confirmed the significant inhibitory effect of this agent on R.cerealis.Large-area field trials also demonstrated its efficacy,with a disease prevention index of 83.52%,which is 1.97%greater than that of the widely used thifluzamide,and it significantly increased the wheat yield.Moreover,this study explored the impacts of Y17991 on the structure and function of the microbial community in wheat rhizosphere soil.Bacterial communities were more strongly affected than fungal communities.Y17991 significantly modulated key amino acid metabolic pathways and certain biosynthetic processes in diseased wheat rhizospheres,and it also enhanced certain biosynthetic pathways and metabolic activities in healthy wheat rhizospheres.Additionally,the application of Y17991 regulated rhizosphere metabolites,thus exerting significant control over the microbial community.We identified 15 microbial strains potentially involved in the prevention and treatment of R.cerealis,and Y17991 treatment promoted the growth of Pedobacter and Bacillus strains.These strains not only aid in plant growth but they also have the potential for disease prevention.In summary,Y17991 application at a reasonable dose does not cause significant disruption to nontarget rhizosphere microbial communities.In future studies,we will continue to investigate the impacts of Y17991 on nonmicrobial components in soil ecosystems,such as protozoa and nematodes.Our research provides a theoretical basis for the scientific application and promotion of new fungicides and offers a significant reference for establishing a comprehensive system for assessing the ecological impact of pesticides on the environment.展开更多
This paper is concerned with the global well-posedness of the solution to the compressible Navier-Stokes/Allen-Cahn system and its sharp interface limit in one-dimensional space.For the perturbations with small energy...This paper is concerned with the global well-posedness of the solution to the compressible Navier-Stokes/Allen-Cahn system and its sharp interface limit in one-dimensional space.For the perturbations with small energy but possibly large oscillations of rarefaction wave solutions near phase separation,and where the strength of the initial phase field could be arbitrarily large,we prove that the solution of the Cauchy problem exists for all time,and converges to the centered rarefaction wave solution of the corresponding standard two-phase Euler equation as the viscosity and the thickness of the interface tend to zero.The proof is mainly based on a scaling argument and a basic energy method.展开更多
Introduction: Cranioencephalic trauma caused by bladed weapons is rare, and that caused by sharp objects is exceptional. The aim of our study was to describe the clinical, therapeutic and evolutionary aspects. Materia...Introduction: Cranioencephalic trauma caused by bladed weapons is rare, and that caused by sharp objects is exceptional. The aim of our study was to describe the clinical, therapeutic and evolutionary aspects. Materials and method: This was a descriptive and analytical study over a 48-month period at CHU la Renaissance from January 1, 2018 to December 31, 2021, concerning patients admitted for penetrating cranioencephalic trauma by pointed object. Results: Twelve cases, all male, of penetrating cranioencephalic sharp-force trauma were identified. The mean age was 34 ± 7 years, with extremes of 11 and 60 years. Farmers and herders accounted for 31% and 25% of cases respectively. The average admission time was 47 hours. Brawls were the circumstances of occurrence in 81.2% of cases. Knives (33%), arrows (25%) and iron bars (16.6%) were the objects used. Altered consciousness was present in 43.8% of cases, and focal deficit in 50%. Scannographic lesions were fracture and/or embarrhment (12 cases), intra-parenchymal haematomas (6 cases) and presence of object in place (4 cases). Surgery was performed in 11 patients. Postoperative outcome was favorable in 9 patients. After 12 months, 2 patients were declared unfit. Conclusion: Penetrating head injuries caused by sharp objects are common in Chad. Urgent surgery can prevent disabling after-effects.展开更多
This study presents a numerical analysis of three-dimensional steady laminar flow in a rectangular channel with a 180-degree sharp turn. The Navier-Stokes equations are solved by using finite difference method for Re ...This study presents a numerical analysis of three-dimensional steady laminar flow in a rectangular channel with a 180-degree sharp turn. The Navier-Stokes equations are solved by using finite difference method for Re = 900. Three-dimensional streamlines and limiting streamlines on wall surface are used to analyze the three-dimensional flow characteristics. Topological theory is applied to limiting streamlines on inner walls of the channel and two-dimensional streamlines at several cross sections. It is also shown that the flow impinges on the end wall of turn and the secondary flow is induced by the curvature in the sharp turn.展开更多
目的探讨项目式学习在护理实习生岗前培训中对锐器伤防护技能培训的效果及其对实习期间锐器伤发生率的影响。方法采用便利抽样法选取2023年3月南昌理工学院医学院护理专业A、B两个班级为研究对象。采用掷硬币法将A班设为常规组,B班设为...目的探讨项目式学习在护理实习生岗前培训中对锐器伤防护技能培训的效果及其对实习期间锐器伤发生率的影响。方法采用便利抽样法选取2023年3月南昌理工学院医学院护理专业A、B两个班级为研究对象。采用掷硬币法将A班设为常规组,B班设为干预组。常规组接受以回顾性强化训练护理操作技能为主的常规岗前培训;干预组在此基础上融入锐器伤防护技能的项目式学习补偿教育。采用柯氏四级培训评估模式在相应阶段自“反应、学习、行为、结果”四个递进的层面全方位评估教育效果。结果A班常规组和B班干预组各纳入56名护理实习生。干预组护理实习生的课程评价评分(128.67±4.39 VS 117.28±6.55)、针刺伤防护知识认知评分(109.11±4.38 VS 96.44±6.72)、安全注射行为评分(38.45±4.91 VS 32.30±5.62)、职业认同感评分(58.02±8.55 VS 51.77±15.86)、岗位胜任力评分(82.59±13.35 VS 75.61±15.09)均高于常规组,差异均有统计学意义(均P<0.05)。干预组护理实习生锐器伤发生率(19.64%VS 57.14%)及平均发生频次(1.45 VS 2.13)均低于常规组;锐器伤后例次干预率(87.50%VS 45.59%)和例次上报率(93.75%VS 32.35%)均高于常规组,差异均有统计学意义(均P<0.05)。结论在护生岗前培训中引入项目式学习的锐器伤防护培训,能有效提升防护技能掌握程度,降低实习期间锐器伤发生率,对培养护生职业防护能力具有重要实践价值。展开更多
传统Sharpe比率将投资收益的标准差作为风险的度量,而实证研究中更关注基金的损失风险而非全部风险,这是收益标准差所无法准确刻画的。针对传统Sharpe比率的这一缺点,本文考虑了用于度量下方风险的指标风险价值VaR(Value at Risk)和预...传统Sharpe比率将投资收益的标准差作为风险的度量,而实证研究中更关注基金的损失风险而非全部风险,这是收益标准差所无法准确刻画的。针对传统Sharpe比率的这一缺点,本文考虑了用于度量下方风险的指标风险价值VaR(Value at Risk)和预期不足ES(Expected Shortfall)来替代投资收益的标准差,从而对传统Sharpe比率进行了调整。这里对VaR和ES进行计算时,运用了经验非参数估计和非参数平滑核估计两种方法。此外,本文还考虑了基金收益随时间波动的动态性,用广义自回归异方差GARCH模型对收益波动进行模拟,考察动态的VaR和ES,在实践中以动态的VaR和ES评价风险收益更加灵活。在实证研究中,本文用传统的Sharpe比率、基于VaR和ES的Sharpe比率以及基于条件VaR和条件ES的条件Sharpe比率对国内证券市场上所有26只封闭式基金在2005-2009年间的业绩进行了实证分析,分析了基金在不同指标下所体现的风险控制能力和收益水平的差别,并基于不同指标对所有基金进行了排名。此外,本文还运用协整检验考察基金收益率与市场基准指数是否存在联动关系,检验证明两者并不存在长期的均衡关系。展开更多
文摘The variable salinity in stored reservoirs connected by a long channel attracts the attention of scientists worldwide,having applications in environmental and geophysical engineering.This study explores the impact of Navier slip conditions on exchange flows within a long channel connecting two large reservoirs of differing salinity.These horizontal density gradients drive the flow.We modify the recent one-dimensional theory,developed to avoid runaway stratification,to account for the presence of uniform slip walls.By adjusting the parameters of the horizontal density gradient based on the slip factor,we resolve analytically various flow regimes ranging from high diffusion to transitional high advection.These regimes are governed by physical parameters like channel aspect ratio,slip factor,Schmidt number,and gravitational Reynolds number.Our solutions align perfectly with ones in the no-slip limit.More importantly,under the conditions of no net flow across the channel and high Schmidt number(where stratification is concentrated near the channel’s mid-layer),we derive a closed-form solution for the slip parameter,aspect ratio,and gravitational Reynolds number that describes the interface’s behavior as a sharp interface separating two distinct zones.This interface,arising from hydrostatic wall gradients,ultimately detaches the low-and high-density regimes throughout the channel when the gravitational Reynolds number is inversely proportional to the aspect ratio for a fixed slip parameter.This phenomenon,observed previously in 2D numerical simulations with no-slip walls in the literature,is thus confirmed by our theoretical results.Our findings further demonstrate that wall slip leads to distinct and diverse flow regimes.
基金supported by the National Natural Science Foundation of China(32270296)the Shenzhen Postdoctoral Scientific Research,China(77000-42100004)+1 种基金the Key Basic Research and Development Program of Hubei Province,China(2020BBA052)the Natural Science Foundation of Guangdong Province,China(2024A1515010498)and the Fundamental Research Funds for the Central Universities,Sun Yat-sen University,China.
文摘Sharp eyespot(Rhizoctonia cerealis)is a widespread soil-borne fungal disease that poses a severe threat to wheat health,and it is one of the main obstacles to achieving stable and high-quality wheat yields in China.Our collaborative team has developed a novel,efficient,and low-toxicity fungicide named Y17991(N-(2-(2,4-bis-(trifluoromethyl)phenoxy)phenyl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide).Preliminary laboratory tests confirmed the significant inhibitory effect of this agent on R.cerealis.Large-area field trials also demonstrated its efficacy,with a disease prevention index of 83.52%,which is 1.97%greater than that of the widely used thifluzamide,and it significantly increased the wheat yield.Moreover,this study explored the impacts of Y17991 on the structure and function of the microbial community in wheat rhizosphere soil.Bacterial communities were more strongly affected than fungal communities.Y17991 significantly modulated key amino acid metabolic pathways and certain biosynthetic processes in diseased wheat rhizospheres,and it also enhanced certain biosynthetic pathways and metabolic activities in healthy wheat rhizospheres.Additionally,the application of Y17991 regulated rhizosphere metabolites,thus exerting significant control over the microbial community.We identified 15 microbial strains potentially involved in the prevention and treatment of R.cerealis,and Y17991 treatment promoted the growth of Pedobacter and Bacillus strains.These strains not only aid in plant growth but they also have the potential for disease prevention.In summary,Y17991 application at a reasonable dose does not cause significant disruption to nontarget rhizosphere microbial communities.In future studies,we will continue to investigate the impacts of Y17991 on nonmicrobial components in soil ecosystems,such as protozoa and nematodes.Our research provides a theoretical basis for the scientific application and promotion of new fungicides and offers a significant reference for establishing a comprehensive system for assessing the ecological impact of pesticides on the environment.
基金supported by the National Natural Science Foundation of China(12361044)supported by the National Natural Science Foundation of China(12171024,11971217,11971020)supported by the Academic and Technical Leaders Training Plan of Jiangxi Province(20212BCJ23027)。
文摘This paper is concerned with the global well-posedness of the solution to the compressible Navier-Stokes/Allen-Cahn system and its sharp interface limit in one-dimensional space.For the perturbations with small energy but possibly large oscillations of rarefaction wave solutions near phase separation,and where the strength of the initial phase field could be arbitrarily large,we prove that the solution of the Cauchy problem exists for all time,and converges to the centered rarefaction wave solution of the corresponding standard two-phase Euler equation as the viscosity and the thickness of the interface tend to zero.The proof is mainly based on a scaling argument and a basic energy method.
文摘Introduction: Cranioencephalic trauma caused by bladed weapons is rare, and that caused by sharp objects is exceptional. The aim of our study was to describe the clinical, therapeutic and evolutionary aspects. Materials and method: This was a descriptive and analytical study over a 48-month period at CHU la Renaissance from January 1, 2018 to December 31, 2021, concerning patients admitted for penetrating cranioencephalic trauma by pointed object. Results: Twelve cases, all male, of penetrating cranioencephalic sharp-force trauma were identified. The mean age was 34 ± 7 years, with extremes of 11 and 60 years. Farmers and herders accounted for 31% and 25% of cases respectively. The average admission time was 47 hours. Brawls were the circumstances of occurrence in 81.2% of cases. Knives (33%), arrows (25%) and iron bars (16.6%) were the objects used. Altered consciousness was present in 43.8% of cases, and focal deficit in 50%. Scannographic lesions were fracture and/or embarrhment (12 cases), intra-parenchymal haematomas (6 cases) and presence of object in place (4 cases). Surgery was performed in 11 patients. Postoperative outcome was favorable in 9 patients. After 12 months, 2 patients were declared unfit. Conclusion: Penetrating head injuries caused by sharp objects are common in Chad. Urgent surgery can prevent disabling after-effects.
文摘This study presents a numerical analysis of three-dimensional steady laminar flow in a rectangular channel with a 180-degree sharp turn. The Navier-Stokes equations are solved by using finite difference method for Re = 900. Three-dimensional streamlines and limiting streamlines on wall surface are used to analyze the three-dimensional flow characteristics. Topological theory is applied to limiting streamlines on inner walls of the channel and two-dimensional streamlines at several cross sections. It is also shown that the flow impinges on the end wall of turn and the secondary flow is induced by the curvature in the sharp turn.
文摘目的探讨项目式学习在护理实习生岗前培训中对锐器伤防护技能培训的效果及其对实习期间锐器伤发生率的影响。方法采用便利抽样法选取2023年3月南昌理工学院医学院护理专业A、B两个班级为研究对象。采用掷硬币法将A班设为常规组,B班设为干预组。常规组接受以回顾性强化训练护理操作技能为主的常规岗前培训;干预组在此基础上融入锐器伤防护技能的项目式学习补偿教育。采用柯氏四级培训评估模式在相应阶段自“反应、学习、行为、结果”四个递进的层面全方位评估教育效果。结果A班常规组和B班干预组各纳入56名护理实习生。干预组护理实习生的课程评价评分(128.67±4.39 VS 117.28±6.55)、针刺伤防护知识认知评分(109.11±4.38 VS 96.44±6.72)、安全注射行为评分(38.45±4.91 VS 32.30±5.62)、职业认同感评分(58.02±8.55 VS 51.77±15.86)、岗位胜任力评分(82.59±13.35 VS 75.61±15.09)均高于常规组,差异均有统计学意义(均P<0.05)。干预组护理实习生锐器伤发生率(19.64%VS 57.14%)及平均发生频次(1.45 VS 2.13)均低于常规组;锐器伤后例次干预率(87.50%VS 45.59%)和例次上报率(93.75%VS 32.35%)均高于常规组,差异均有统计学意义(均P<0.05)。结论在护生岗前培训中引入项目式学习的锐器伤防护培训,能有效提升防护技能掌握程度,降低实习期间锐器伤发生率,对培养护生职业防护能力具有重要实践价值。
文摘传统Sharpe比率将投资收益的标准差作为风险的度量,而实证研究中更关注基金的损失风险而非全部风险,这是收益标准差所无法准确刻画的。针对传统Sharpe比率的这一缺点,本文考虑了用于度量下方风险的指标风险价值VaR(Value at Risk)和预期不足ES(Expected Shortfall)来替代投资收益的标准差,从而对传统Sharpe比率进行了调整。这里对VaR和ES进行计算时,运用了经验非参数估计和非参数平滑核估计两种方法。此外,本文还考虑了基金收益随时间波动的动态性,用广义自回归异方差GARCH模型对收益波动进行模拟,考察动态的VaR和ES,在实践中以动态的VaR和ES评价风险收益更加灵活。在实证研究中,本文用传统的Sharpe比率、基于VaR和ES的Sharpe比率以及基于条件VaR和条件ES的条件Sharpe比率对国内证券市场上所有26只封闭式基金在2005-2009年间的业绩进行了实证分析,分析了基金在不同指标下所体现的风险控制能力和收益水平的差别,并基于不同指标对所有基金进行了排名。此外,本文还运用协整检验考察基金收益率与市场基准指数是否存在联动关系,检验证明两者并不存在长期的均衡关系。
