Animals employ compasses during navigation,but little attention has been paid to how accuracy is maintained in the face of compass error,which is inevitable in biological systems.The use of multiple landmarks may min&...Animals employ compasses during navigation,but little attention has been paid to how accuracy is maintained in the face of compass error,which is inevitable in biological systems.The use of multiple landmarks may minimize the effect of compass error.We allowed Clark’s nutcrackers to cache seeds in an outdoor aviary with either one or four landmarks present,and subsequently subjected them to small clock-shifts mimicking the effects of compass error.As predicted,the results showed a significant decrease in search accuracy following the clock-shift when one landmark was present but not when four landmarks were present.These results support that nutcrackers encode information from the sun as well as terrestrial landmarks,and these spatial cues are used in a flexible manner.Overall,our results are important as they support the hypothesis that multiple landmarks may be used during situations where the sun compass has even a small amount of error.展开更多
In this paper, we consider the following noncooperative elliptic systems where Ω is a bounded domain in R<sup>N</sup> with smooth boundary ∂Ω, λ,δ,γ are real parameters, and . We assume that F is subq...In this paper, we consider the following noncooperative elliptic systems where Ω is a bounded domain in R<sup>N</sup> with smooth boundary ∂Ω, λ,δ,γ are real parameters, and . We assume that F is subquadratic at zero with respect to the variables u,v. By using a variant Clark’s theorem, we obtain infinitely many nontrivial solutions (u<sub>k</sub><sub></sub>,v<sub>k</sub>) with as k → ∞. Compared with the existing literature, we do not need to assume the behavior of the nonlinearity ∇F at infinity.展开更多
Clarke’s matrix has been applied as a phase-mode transformation matrix to three-phase transmission lines substituting the eigenvector matrices. Considering symmetrical untransposed three-phase lines, an actual symmet...Clarke’s matrix has been applied as a phase-mode transformation matrix to three-phase transmission lines substituting the eigenvector matrices. Considering symmetrical untransposed three-phase lines, an actual symmetrical three-phase line on untransposed conditions is associated with Clarke’s matrix for error and frequency scan analyses in this paper. Error analyses are calculated for the eigenvalue diagonal elements obtained from Clarke’s matrix. The eigenvalue off-diagonal elements from the Clarke’s matrix application are compared to the correspondent exact eigenvalues. Based on the characteristic impedance and propagation function values, the frequency scan analyses show that there are great differences between the Clarke’s matrix results and the exact ones, considering frequency values from 10 kHz to 1 MHz. A correction procedure is applied obtaining two new transformation matrices. These matrices lead to good approximated results when compared to the exact ones. With the correction procedure applied to Clarke’s matrix, the relative values of the eigenvalue matrix off-diagonal element obtained from Clarke’s matrix are decreased while the frequency scan results are improved. The steps of correction procedure application are detailed, investigating the influence of each step on the obtained two new phase-mode transformation matrices.展开更多
In ruminant field of digestive research, the appeal to methods of less invasive studies and reproducing the in vivo conditions is essential. The objective of the present study was to determine whether the conditions c...In ruminant field of digestive research, the appeal to methods of less invasive studies and reproducing the in vivo conditions is essential. The objective of the present study was to determine whether the conditions created with the proposed in vitro batch culture was an accurate reproduction of the physico-chemical and fermentative ruminal conditions observed in vivo. Two experiments were conducted to compare ruminal reducing power measured in vitro, i.e. in batch cultures or, in vivo i.e. in live animals: dairy cows at maintenance (Experiment 1) and lactating dairy cows (Experiment 2). In Experiment 1, at the beginning of incubation period, in vitro redox potential (Eh), pH and Clark’s exponent (rH) values were significantly higher than in vivo (+42 mV, +0.25 and +1.9, respectively) whereas volatile fatty acids (VFA) contents were 2.6 fold lower on average. At the end of incubation, Eh, rH values and VFA contents were similar between both methods whereas pH still remained different. In Experiment 2, at the beginning and at the end of incubation period, in vitro Eh, pH and rH values differed significantly than in vivo. As a result, the in vitro method did not provide a tool to evaluate accurately the level of the reducing status of ruminal milieu compared with in vivo measurement. Nonetheless, it provided strong reducing conditions after 8 h of incubation with levels of rH relatively closed to those observed in vivo. In vitro batch culture could be a good alternative to in vivo trials for a screening approach from an ethic and economic point of view in ruminant field of research.展开更多
Based on the differential properties of the smoothing metric projector onto the second-order cone,we prove that,for a locally optimal solution to a nonlinear second-order cone programming problem,the nonsingularity of...Based on the differential properties of the smoothing metric projector onto the second-order cone,we prove that,for a locally optimal solution to a nonlinear second-order cone programming problem,the nonsingularity of the Clarke's generalized Jacobian of the smoothing Karush-Kuhn-Tucker system,constructed by the smoothing metric projector,is equivalent to the strong second-order sufficient condition and constraint nondegeneracy,which is in turn equivalent to the strong regularity of the Karush-Kuhn-Tucker point.Moreover,this nonsingularity property guarantees the quadratic convergence of the corresponding smoothing Newton method for solving a Karush-Kuhn-Tucker point.Interestingly,the analysis does not need the strict complementarity condition.展开更多
基金a Natural Sciences Research Council grant RGPIN/312379-2009 to DMK,and a National Institutes of Health grant MH-61810 to AK.
文摘Animals employ compasses during navigation,but little attention has been paid to how accuracy is maintained in the face of compass error,which is inevitable in biological systems.The use of multiple landmarks may minimize the effect of compass error.We allowed Clark’s nutcrackers to cache seeds in an outdoor aviary with either one or four landmarks present,and subsequently subjected them to small clock-shifts mimicking the effects of compass error.As predicted,the results showed a significant decrease in search accuracy following the clock-shift when one landmark was present but not when four landmarks were present.These results support that nutcrackers encode information from the sun as well as terrestrial landmarks,and these spatial cues are used in a flexible manner.Overall,our results are important as they support the hypothesis that multiple landmarks may be used during situations where the sun compass has even a small amount of error.
文摘In this paper, we consider the following noncooperative elliptic systems where Ω is a bounded domain in R<sup>N</sup> with smooth boundary ∂Ω, λ,δ,γ are real parameters, and . We assume that F is subquadratic at zero with respect to the variables u,v. By using a variant Clark’s theorem, we obtain infinitely many nontrivial solutions (u<sub>k</sub><sub></sub>,v<sub>k</sub>) with as k → ∞. Compared with the existing literature, we do not need to assume the behavior of the nonlinearity ∇F at infinity.
文摘Clarke’s matrix has been applied as a phase-mode transformation matrix to three-phase transmission lines substituting the eigenvector matrices. Considering symmetrical untransposed three-phase lines, an actual symmetrical three-phase line on untransposed conditions is associated with Clarke’s matrix for error and frequency scan analyses in this paper. Error analyses are calculated for the eigenvalue diagonal elements obtained from Clarke’s matrix. The eigenvalue off-diagonal elements from the Clarke’s matrix application are compared to the correspondent exact eigenvalues. Based on the characteristic impedance and propagation function values, the frequency scan analyses show that there are great differences between the Clarke’s matrix results and the exact ones, considering frequency values from 10 kHz to 1 MHz. A correction procedure is applied obtaining two new transformation matrices. These matrices lead to good approximated results when compared to the exact ones. With the correction procedure applied to Clarke’s matrix, the relative values of the eigenvalue matrix off-diagonal element obtained from Clarke’s matrix are decreased while the frequency scan results are improved. The steps of correction procedure application are detailed, investigating the influence of each step on the obtained two new phase-mode transformation matrices.
文摘In ruminant field of digestive research, the appeal to methods of less invasive studies and reproducing the in vivo conditions is essential. The objective of the present study was to determine whether the conditions created with the proposed in vitro batch culture was an accurate reproduction of the physico-chemical and fermentative ruminal conditions observed in vivo. Two experiments were conducted to compare ruminal reducing power measured in vitro, i.e. in batch cultures or, in vivo i.e. in live animals: dairy cows at maintenance (Experiment 1) and lactating dairy cows (Experiment 2). In Experiment 1, at the beginning of incubation period, in vitro redox potential (Eh), pH and Clark’s exponent (rH) values were significantly higher than in vivo (+42 mV, +0.25 and +1.9, respectively) whereas volatile fatty acids (VFA) contents were 2.6 fold lower on average. At the end of incubation, Eh, rH values and VFA contents were similar between both methods whereas pH still remained different. In Experiment 2, at the beginning and at the end of incubation period, in vitro Eh, pH and rH values differed significantly than in vivo. As a result, the in vitro method did not provide a tool to evaluate accurately the level of the reducing status of ruminal milieu compared with in vivo measurement. Nonetheless, it provided strong reducing conditions after 8 h of incubation with levels of rH relatively closed to those observed in vivo. In vitro batch culture could be a good alternative to in vivo trials for a screening approach from an ethic and economic point of view in ruminant field of research.
基金the Natural Science Foundation of China(Grant No.10471159,No.10171118)the key project of the Chinese Ministry of Education,Supported by Program for New Century Excellent Talents in University,Education Commission project Research Foundation of Chongqing(Grant No.K J060818,KJ060804)+1 种基金the Research Fund for the Doctoral Program of Chongqing Normal University(Grant No.06XLB023)the project supported by Chongqing Key Laboratory of Operations Research and System Engineering.
基金supported by National Natural Science Foundation of China (Grant Nos.10771026,10901094)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry of China
文摘Based on the differential properties of the smoothing metric projector onto the second-order cone,we prove that,for a locally optimal solution to a nonlinear second-order cone programming problem,the nonsingularity of the Clarke's generalized Jacobian of the smoothing Karush-Kuhn-Tucker system,constructed by the smoothing metric projector,is equivalent to the strong second-order sufficient condition and constraint nondegeneracy,which is in turn equivalent to the strong regularity of the Karush-Kuhn-Tucker point.Moreover,this nonsingularity property guarantees the quadratic convergence of the corresponding smoothing Newton method for solving a Karush-Kuhn-Tucker point.Interestingly,the analysis does not need the strict complementarity condition.
