Drug resistance in an age-of-infection model

ABSTRACT

In the case of a disease spreading over a time-scale comparable to the average lifetime in a host population, when the infectiousness of individuals depends on the tine since the onset of infection and when infections involve both drug-sensitive and drug-resistant strains of a pathogen, resistance may develop during the treatment of drug-sensitive strains. If increasing the treatment rate reduces the reproduction number of the drug-sensitive strain to a value below the reproduction number of the drug-resistant strain, then the disease may persist at a boundary equilibrium where only drug-resistant infection is present.     

箪食瓢饮:河北涉县旱作梯田系统的饮食体系

作为中国重要农业文化遗产,河北涉县旱作梯田系统是当地居民积累生活经验、寻找生存之道,最终实现农业永续发展的智慧结晶。 本文以其核心区域王金庄村居民的日常饮食入手,意在描述梯田社会中食物从破土而出到送入口中的全过程,呈现当地在自然与文化共同作用下所形成的饮食结构和饮食习惯。 这种与自然相适应的文化模式以及由此而生的生态观念,形成了以藏粮于地、储粮于仓、节粮于口为主要内容的饮食体系,影响着当地人的行为选择,也发挥了重要的生态调节功能。     

Local composite quantile regression estimation of time-varying parameter vector for multidimensional time-inhomogeneous diffusion models

This paper is dedicated to the study of the composite quantile regression (CQR) estimations of time-varying parameter vectors for multidimensional diffusion models. Based on the local linear fitting for parameter vectors, we propose the local linear CQR estimations of the drift parameter vectors, and verify their asymptotic biases, asymptotic variances and asymptotic normality. Moreover, we discuss the asymptotic relative efficiency (ARE) of the local linear CQR estimations with respect to the local linear least-squares estimations. We obtain that the local estimations that we proposed are much more efficient than the local linear least-squares estimations. Simulation studies are constructed to show the performance of the estimations proposed.     

A method for choosing the smoothing parameter in a semi-parametric model for detecting change-points in blood flow

In a smoothing spline model with unknown change-points, the choice of the smoothing parameter strongly influences the estimation of the change-point locations and the function at the change-points. In a tumor biology example, where change-points in blood flow in response to treatment were of interest, choosing the smoothing parameter based on minimizing generalized cross-validation (GCV) gave unsatisfactory estimates of the change-points. We propose a new method, aGCV, that re-weights the residual sum of squares and generalized degrees of freedom terms from GCV. The weight is chosen to maximize the decrease in the generalized degrees of freedom as a function of the weight value, while simultaneously minimizing aGCV as a function of the smoothing parameter and the change-points. Compared with GCV, simulation studies suggest that the aGCV method yields improved estimates of the change-point and the value of the function at the change-point.     

网络语境下的大学生榜样教育研

互联网的广泛应用使大学生榜样教育在形式上和内容上都得到了丰富和深化，但仍然存在网络推广方式还不能适应大学生成长要求、传统榜样的影响正在弱化等问题。运用问卷调查法，分析了当前网络语境下大学生榜样教育的现状以及存在的问题，剖析了榜样教育弱化的原因，进而提出了适合网络语境下的大学生榜样教育路径。     

西方平等理论从古典自然法学到新自然法学的嬗变

平等是一个非常复杂和抽象的范畴,西方法学对平等理论的热爱和追逐从未停止过,从古典自然法学追求的抽象的平等的政治理想,到新自然法学对平等的制度设计的现实关怀,平等理论随着自然法学的发展实现了其自身的嬗变,这种改变也是时代的要求、历史的必然。     

How do I get my way? A meta-analytic review of research on influence tactics

Despite considerable research investigating the role of influence tactics on work-related outcomes in organizations, consensus on the effectiveness of influence tactics has been elusive. Specifically, there is a lack of integration concerning the relationships between proactive influence tactics and their outcomes. We investigate the effectiveness of 11 influence tactics from a comprehensive perspective using meta-analytic techniques. In particular, the current study focuses on relationships between each of the 11 influence tactics (i.e., rational persuasion, exchange, inspirational appeal, legitimating, apprising, pressure, collaboration, ingratiation, consultation, personal appeals, and coalition) and task- and relations-oriented outcomes. In addition, we investigate the moderating effects of the direction of influence tactics, measurement of influence tactics, singular influence tactic (versus use of a combination of influence tactics), independence of data sources, and study setting involved in the study. Regardless of task- and relations-oriented outcomes, based on 49 independent samples (N = 8987), our results show positive relationships between outcomes and rational persuasion, inspirational appeal, apprising, collaboration, ingratiation, consultation, and a negative relationship between pressure and outcomes. Rational persuasion is the only tactic which held stable positive relationships with both categories of outcomes regardless of moderating factors. Implications and directions for future research in the area of influence tactics are discussed.     

A robust and efficient estimation method for nonparametric models with jump points

Nonparametric models with jump points have been considered by many researchers. However, most existing methods based on least squares or likelihood are sensitive when there are outliers or the error distribution is heavy tailed. In this article, a local piecewise-modal method is proposed to estimate the regression function with jump points in nonparametric models, and a piecewise-modal EM algorithm is introduced to estimate the proposed estimator. Under some regular conditions, the large-sample theory is established for the proposed estimators. Several simulations are presented to evaluate the performances of the proposed method, which shows that the proposed estimator is more efficient than the local piecewise-polynomial regression estimator in the presence of outliers or heavy tail error distribution. What is more, the proposed procedure is asymptotically equivalent to the local piecewise-polynomial regression estimator under the assumption that the error distribution is a Gaussian distribution. The proposed method is further illustrated via the sea-level pressures.     

Comparison of leadership styles in Confucian Asian countries

The purpose of this study was to examine the overall impact of four leadership styles (charismatic, directive, participative, and supportive) in four Confucian Asian countries, China, Japan, South Korea, and Singapore, by reviewing recent studies conducted in those countries. By reviewing 38 studies selected from 430 studies published between 2005 and 2016, we identify the impact of the four leadership styles in the four Asian countries. We start with the research question and purpose, and then propose criteria for selecting the relevant recent studies followed by a review of cultural heritage and its influence on leadership in the four Asian countries. We summarize and review the studies and, finally, discuss the theoretical and practical contributions of this study.     

利用数学软件复原碎纸片的方法

研究了碎纸片的拼接复原问题,建立了合理有效的碎纸片拼接复原的数学模型；给出了数学软件实现自动拼接的具体算法；结合人工拼接得出复原图片；最后,对所给的拼接方法提出了改进方向.