Allowable levels for pesticide residues in foods, known as tolerances in the US and as maximum residue limits （MRLs） in much of the world, are widely yet inappropriately perceived as levels of safety concern. A nove...Allowable levels for pesticide residues in foods, known as tolerances in the US and as maximum residue limits （MRLs） in much of the world, are widely yet inappropriately perceived as levels of safety concern. A novel approach to develop scientifically defensible levels of safety concern is presented and an example to determine acute and chronic pesticide food safety standard （PFSS） levels for the fungicide captan on strawberries is provided. Using this approach, the chronic PFSS level for captan on strawberries was determined to be 2 000 mg kg-1 and the acute PFSS level was determined to be 250 mg kg-1. Both levels are far above the existing tolerance and MRLs that commonly range from 3 to 20 mg kg-~, and provide evidence that captan residues detected at levels greater than the tolerance or MRLs are not of acute or chronic health concern even though they represent violative residues. The benefits of developing the PFSS approach to serve as a companion to existing tolerances/MRLs include a greater understanding concerning the health significance, if any, from exposure to violative pesticide residues. In addition, the PFSS approach can be universally applied to all potential pesticide residues on all food commodities, can be modified by specific jurisdictions to take into account differences in food consumption practices, and can help prioritize food residue monitoring by identifying the pesticide/commodity combinations of the greatest potential food safety concern and guiding development of field level analytical methods to detect pesticide residues on prioritized pesticide/commodity combinations.展开更多
This paper investigates the problem of almost sure limit theorem for the maximum of quasi-stationary sequence based on the result of Turkman and Walker. We prove an almost sure limit theorem for the maximum of a class...This paper investigates the problem of almost sure limit theorem for the maximum of quasi-stationary sequence based on the result of Turkman and Walker. We prove an almost sure limit theorem for the maximum of a class of quasi-stationary sequence under weak dependence conditions of D （uk, un） and αtm,ln = 0 （（log log n）-（1＋ε））.展开更多
The problem of k-llmited maximum base was specified into two special problems of k-limited maximum base; that is, let subset D of the problem of k-limited maximum base be an independent set and a circuit of the matroi...The problem of k-llmited maximum base was specified into two special problems of k-limited maximum base; that is, let subset D of the problem of k-limited maximum base be an independent set and a circuit of the matroid, respectively. It was proved that under this circumstance the collections of k-limited base satisfy base axioms. Then a new matroid was determined, and the problem of k-limited maximum base was transformed to the problem of maximum base of this new matroid. Aiming at the problem, two algorithm% which in essence are greedy algorithms based on former matroid, were presented for the two special problems of k- limited maximum base. They were proved to be reasonable and more efficient than the algorithm presented by Ma Zhongfan in view of the complexity of algorithm.展开更多
A large number of criteria has been developed to predict material instabilities, but their choice is limited by the lack of existing comparison of their theoretical basis and application domains. To overcome this limi...A large number of criteria has been developed to predict material instabilities, but their choice is limited by the lack of existing comparison of their theoretical basis and application domains. To overcome this limitation, a theoretical and numerical comparison of two major models used to predict diffuse necking is present in this paper. Limit Point Bifurcation criterion is first introduced. An original formulation of the Maximum Force Criterion (MFC), taking into account the effects of damage and isotropic and kinematic hardenings, is then proposed. Strong connections are shown between them by comparing their theoretical basis. Numerical Forming Limit Diagrams at diffuse necking obtained with these criteria for different metallic materials are given. They illustrate the theoretical link and similar predictions are shown for both models.展开更多
Recent discoveries show steady improvements in life expectancy during modern decades. Does this support that humans continue to live longer in future? We recently put forward the maximum survival tendency, as found in...Recent discoveries show steady improvements in life expectancy during modern decades. Does this support that humans continue to live longer in future? We recently put forward the maximum survival tendency, as found in survival curves of industrialized countries, which is described by extended Weibull model with agedependent stretched exponent. The maximum survival ten dency suggests that human survival dynamics may possess its intrinsic limit, beyond which survival is inevitably forbidden. Based on such tendency, we develop the model and explore the patterns in the maximum lifespan limits from industrialized countries during recent three decades. This analysis strategy is simple and useful to interpret the complicated human survival dynamics.展开更多
A type of three-pitch fluctuating speed ratio limited-slip differential （TPLSD） is presented for the first time, analyzed its working principle, introduced the tooth profile design method of using non-involute tooth...A type of three-pitch fluctuating speed ratio limited-slip differential （TPLSD） is presented for the first time, analyzed its working principle, introduced the tooth profile design method of using non-involute tooth profile and separated tooth profile design along the pitch line. Performance comparison between vehicles equipped with three-pitch fluctuating speed ratio limited-slip differential and common open differefitial is finished. The data from experiments prove that three-pitch fluctuating speed ratio limited-slip differential can increase the traction of a vehicle, improve its acceleration performance, decrease braking distance and limit sideslip. The basic structure of new differential is the same of open differential, the only difference is that they have different tooth profile, so the new differential has a high performance price.展开更多
With the rapid development of society and economy, the market of power engineering construction is expanding continuously, and all enterprises and units are participating in bidding activities more and more actively. ...With the rapid development of society and economy, the market of power engineering construction is expanding continuously, and all enterprises and units are participating in bidding activities more and more actively. Through participating in the work of several power construction projects, and through analyzing the key points of the establishment of the maximum bid price limit in the power industry, this paper aims to establish a reasonable and feasible price limit for bidding and provide specific guidance, which will provide a certain reference for the establishment of the maximum bid price limit for similar projects in the power industry.展开更多
This paper deals with the problems of consistency and strong consistency of the maximum likelihood estimators of the mean and variance of the drift fractional Brownian motions observed at discrete time instants. Both ...This paper deals with the problems of consistency and strong consistency of the maximum likelihood estimators of the mean and variance of the drift fractional Brownian motions observed at discrete time instants. Both the central limit theorem and the Berry-Ess′een bounds for these estimators are obtained by using the Stein’s method via Malliavin calculus.展开更多
基金the Chilean Government and the National Commission for Scientific and Technological Research (CONICYT) for supporting this work through the Becas Chile Scholarships
文摘Allowable levels for pesticide residues in foods, known as tolerances in the US and as maximum residue limits （MRLs） in much of the world, are widely yet inappropriately perceived as levels of safety concern. A novel approach to develop scientifically defensible levels of safety concern is presented and an example to determine acute and chronic pesticide food safety standard （PFSS） levels for the fungicide captan on strawberries is provided. Using this approach, the chronic PFSS level for captan on strawberries was determined to be 2 000 mg kg-1 and the acute PFSS level was determined to be 250 mg kg-1. Both levels are far above the existing tolerance and MRLs that commonly range from 3 to 20 mg kg-~, and provide evidence that captan residues detected at levels greater than the tolerance or MRLs are not of acute or chronic health concern even though they represent violative residues. The benefits of developing the PFSS approach to serve as a companion to existing tolerances/MRLs include a greater understanding concerning the health significance, if any, from exposure to violative pesticide residues. In addition, the PFSS approach can be universally applied to all potential pesticide residues on all food commodities, can be modified by specific jurisdictions to take into account differences in food consumption practices, and can help prioritize food residue monitoring by identifying the pesticide/commodity combinations of the greatest potential food safety concern and guiding development of field level analytical methods to detect pesticide residues on prioritized pesticide/commodity combinations.
基金Project supported by the National Natural Science Foundation of China(11171275)the Natural Science Foundation Project of CQ(cstc2012jjA00029)Liaocheng University Foundation(X09005)
文摘This paper investigates the problem of almost sure limit theorem for the maximum of quasi-stationary sequence based on the result of Turkman and Walker. We prove an almost sure limit theorem for the maximum of a class of quasi-stationary sequence under weak dependence conditions of D （uk, un） and αtm,ln = 0 （（log log n）-（1＋ε））.
文摘The problem of k-llmited maximum base was specified into two special problems of k-limited maximum base; that is, let subset D of the problem of k-limited maximum base be an independent set and a circuit of the matroid, respectively. It was proved that under this circumstance the collections of k-limited base satisfy base axioms. Then a new matroid was determined, and the problem of k-limited maximum base was transformed to the problem of maximum base of this new matroid. Aiming at the problem, two algorithm% which in essence are greedy algorithms based on former matroid, were presented for the two special problems of k- limited maximum base. They were proved to be reasonable and more efficient than the algorithm presented by Ma Zhongfan in view of the complexity of algorithm.
文摘A large number of criteria has been developed to predict material instabilities, but their choice is limited by the lack of existing comparison of their theoretical basis and application domains. To overcome this limitation, a theoretical and numerical comparison of two major models used to predict diffuse necking is present in this paper. Limit Point Bifurcation criterion is first introduced. An original formulation of the Maximum Force Criterion (MFC), taking into account the effects of damage and isotropic and kinematic hardenings, is then proposed. Strong connections are shown between them by comparing their theoretical basis. Numerical Forming Limit Diagrams at diffuse necking obtained with these criteria for different metallic materials are given. They illustrate the theoretical link and similar predictions are shown for both models.
文摘Recent discoveries show steady improvements in life expectancy during modern decades. Does this support that humans continue to live longer in future? We recently put forward the maximum survival tendency, as found in survival curves of industrialized countries, which is described by extended Weibull model with agedependent stretched exponent. The maximum survival ten dency suggests that human survival dynamics may possess its intrinsic limit, beyond which survival is inevitably forbidden. Based on such tendency, we develop the model and explore the patterns in the maximum lifespan limits from industrialized countries during recent three decades. This analysis strategy is simple and useful to interpret the complicated human survival dynamics.
基金supported by Western-Area Transportation-Construction Scientific and Technological Project (No.200331822322)
文摘A type of three-pitch fluctuating speed ratio limited-slip differential （TPLSD） is presented for the first time, analyzed its working principle, introduced the tooth profile design method of using non-involute tooth profile and separated tooth profile design along the pitch line. Performance comparison between vehicles equipped with three-pitch fluctuating speed ratio limited-slip differential and common open differefitial is finished. The data from experiments prove that three-pitch fluctuating speed ratio limited-slip differential can increase the traction of a vehicle, improve its acceleration performance, decrease braking distance and limit sideslip. The basic structure of new differential is the same of open differential, the only difference is that they have different tooth profile, so the new differential has a high performance price.
文摘With the rapid development of society and economy, the market of power engineering construction is expanding continuously, and all enterprises and units are participating in bidding activities more and more actively. Through participating in the work of several power construction projects, and through analyzing the key points of the establishment of the maximum bid price limit in the power industry, this paper aims to establish a reasonable and feasible price limit for bidding and provide specific guidance, which will provide a certain reference for the establishment of the maximum bid price limit for similar projects in the power industry.
基金supported by the National Science Foundations (DMS0504783 DMS0604207)National Science Fund for Distinguished Young Scholars of China (70825005)
文摘This paper deals with the problems of consistency and strong consistency of the maximum likelihood estimators of the mean and variance of the drift fractional Brownian motions observed at discrete time instants. Both the central limit theorem and the Berry-Ess′een bounds for these estimators are obtained by using the Stein’s method via Malliavin calculus.
