Chlorpyrifos and dimethoate are overused agricultural pesticides that can trigger trophic cascades, resulting in toxicity to both terrestrial and aquatic organisms as well as altered ecosystems. In previous studies, s...Chlorpyrifos and dimethoate are overused agricultural pesticides that can trigger trophic cascades, resulting in toxicity to both terrestrial and aquatic organisms as well as altered ecosystems. In previous studies, substantial attention has been given to the effects of pesticides on vertebrate species and, to a lesser extent, species of zooplankton. The present study was designed to show that the fission time effective concentration in ciliates is a potential aquatic detection index for environmental monitoring. The ciliate Urostyla grandis was treated with doses of chlorpyrifos and dimethoate. After exposed to the pesticides, the LC_(50)(i.e., concentration that killed 50% of the ciliate cells within 24 h) values were 0.029 mg L^(-1) for chlorpyrifos and 0.0685 mg L^(-1) for dimethoate. The fission time effective concentrations after 168 h of exposure were 0.0075–0.0093 mg L^(-1) for chlorpyrifos and 0.2640–0.2750 mg L^(-1) for dimethoate. These results show that the fission time effective concentration is lower than the LC_(50) value in ciliates, indicating that fission time effective concentration is more suitable than the LC_(50) value for environmental monitoring using ciliates. The effects of chlorpyrifos and dimethoate on ciliate cell ultrastructures included agglutination of chromatin in the macronucleus, protruded and discontinuous macronuclear and micronuclear membranes, loss of integrity of mitochondrial membranes and contents, and abscission and deformation of the adoral zone of membranelles.展开更多
Dissipation retards fission, resulting in a drop in the first-chance fission probability of a fissioning nucleus with respect to its statistical model value. We use the Langevin model to compute the evolution of the d...Dissipation retards fission, resulting in a drop in the first-chance fission probability of a fissioning nucleus with respect to its statistical model value. We use the Langevin model to compute the evolution of the drop(due to friction), P_(f0)^(drop), for the fissioning systems^(220)Th and ^(240)Cf with the presaddle friction strength(b). The firstchance fission probability is shown to depend sensitively on b, and the sensitivity is apparently greater than that of the total fission probability. We further find that although the total fission probability of heavy ^(240)Cf is insensitive to b, its first-chance fission probability is quite sensitive to b.These results suggest that, to strongly limit the presaddle friction strength, an optimal experimental avenue is to measure the first-chance fission probability of heavy fissioning nuclei.展开更多
A generalized Boussinesq equation that includes the dissipation effect is derived to describe a kind of algebraic Rossby solitary waves in a rotating fluid by employing perturbation expansions and stretching transform...A generalized Boussinesq equation that includes the dissipation effect is derived to describe a kind of algebraic Rossby solitary waves in a rotating fluid by employing perturbation expansions and stretching transformations of time and space.Using this equation, the conservation laws of algebraic Rossby solitary waves are discussed. It is found that the mass, the momentum, the energy, and the velocity of center of gravity of the algebraic solitary waves are conserved in the propagation process. Finally, the analytical solution of the equation is generated. Based on the analytical solution, the properties of the algebraic solitary waves and the dissipation effect are discussed. The results point out that, similar to classic solitary waves,the dissipation can cause the amplitude and the speed of solitary waves to decrease; however, unlike classic solitary waves,the algebraic solitary waves can split during propagation and the decrease of the detuning parameter can accelerate the occurrence of the solitary waves fission phenomenon.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 31601866 and 31501844)the Heilongjiang Province Colleges and Universities Youth Innovative Training Program (Nos. UNPYSCT2017178 and 2017180)
文摘Chlorpyrifos and dimethoate are overused agricultural pesticides that can trigger trophic cascades, resulting in toxicity to both terrestrial and aquatic organisms as well as altered ecosystems. In previous studies, substantial attention has been given to the effects of pesticides on vertebrate species and, to a lesser extent, species of zooplankton. The present study was designed to show that the fission time effective concentration in ciliates is a potential aquatic detection index for environmental monitoring. The ciliate Urostyla grandis was treated with doses of chlorpyrifos and dimethoate. After exposed to the pesticides, the LC_(50)(i.e., concentration that killed 50% of the ciliate cells within 24 h) values were 0.029 mg L^(-1) for chlorpyrifos and 0.0685 mg L^(-1) for dimethoate. The fission time effective concentrations after 168 h of exposure were 0.0075–0.0093 mg L^(-1) for chlorpyrifos and 0.2640–0.2750 mg L^(-1) for dimethoate. These results show that the fission time effective concentration is lower than the LC_(50) value in ciliates, indicating that fission time effective concentration is more suitable than the LC_(50) value for environmental monitoring using ciliates. The effects of chlorpyrifos and dimethoate on ciliate cell ultrastructures included agglutination of chromatin in the macronucleus, protruded and discontinuous macronuclear and micronuclear membranes, loss of integrity of mitochondrial membranes and contents, and abscission and deformation of the adoral zone of membranelles.
基金supported by the National Nature Science Foundation of China(No.11575044)
文摘Dissipation retards fission, resulting in a drop in the first-chance fission probability of a fissioning nucleus with respect to its statistical model value. We use the Langevin model to compute the evolution of the drop(due to friction), P_(f0)^(drop), for the fissioning systems^(220)Th and ^(240)Cf with the presaddle friction strength(b). The firstchance fission probability is shown to depend sensitively on b, and the sensitivity is apparently greater than that of the total fission probability. We further find that although the total fission probability of heavy ^(240)Cf is insensitive to b, its first-chance fission probability is quite sensitive to b.These results suggest that, to strongly limit the presaddle friction strength, an optimal experimental avenue is to measure the first-chance fission probability of heavy fissioning nuclei.
基金Project supported by the Shandong Provincial Key Laboratory of Marine Ecology and Environment and Disaster Prevention and Mitigation Project,China(Grant No.2012010)the National Natural Science Foundation of China(Grant Nos.41205082 and 41476019)+1 种基金the Special Funds for Theoretical Physics of the National Natural Science Foundation of China(Grant No.11447205)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China
文摘A generalized Boussinesq equation that includes the dissipation effect is derived to describe a kind of algebraic Rossby solitary waves in a rotating fluid by employing perturbation expansions and stretching transformations of time and space.Using this equation, the conservation laws of algebraic Rossby solitary waves are discussed. It is found that the mass, the momentum, the energy, and the velocity of center of gravity of the algebraic solitary waves are conserved in the propagation process. Finally, the analytical solution of the equation is generated. Based on the analytical solution, the properties of the algebraic solitary waves and the dissipation effect are discussed. The results point out that, similar to classic solitary waves,the dissipation can cause the amplitude and the speed of solitary waves to decrease; however, unlike classic solitary waves,the algebraic solitary waves can split during propagation and the decrease of the detuning parameter can accelerate the occurrence of the solitary waves fission phenomenon.
