随机Lotka-Volterra系统的稳定性

利用Lyapunov方法与K．lto公式及鞅的理论,研究了随机Lotka-Volterra系统正平衡点的全局渐近稳定性．得到了随机全局渐近稳定的主要定理,并以确定性系统的全局稳定性作为定理的推论．     

具有leakage时滞与随机干扰的离散神经网络渐近稳定性分析

研究了一类具有leakage时滞与随机干扰的离散型神经网络的全局渐近稳定性问题．利用一种新的时滞分割方法将时滞区间分割为多个区间．通过构造新的Lyapunov泛函得到了基于线性矩阵不等式（LMI）的渐近稳定性判据．该判据在获得更小的保守性同时也降低了计算的复杂度．     

在有限资源条件下的肺结核模型研究

讨论了有限资源下的肺结核模型,得到了基本再生数,考虑了模型的双稳定性,用第二加型复合矩阵研究了模型平衡点的全局渐近稳定性．最后数值模拟验证理论结果．     

一类竞争扩散方程组在Neumann边条件下解的渐近行为

本文主要采用比较方法讨论了一类竞争扩散方程组在Neumann边条件下解的渐近行为,得到了解的稳定性区域．     

中立型时滞Volterra系统解的稳定性

本文研究中立型时滞Volterra系统解的渐近稳定性，得到系统的正常数平衡点为渐近稳定的充分条件，发展了文献〔6〕的结果，回答了文献〔7〕所留下的一个未解决问题．     

具有扩散和放养的时滞竞争系统的正周期解

主要研究缀块环境下具有扩散和放养的时滞Lotka-Volterra竞争系统,得到了系统的周期解存在性,唯一性和全局渐近稳定性的充分条件．     

具有庇护所的三种群捕食者-食饵模型

讨论了一类具有庇护所的自治三种群捕食者一食饵模型,运用Liapunov函数方法,得到了该模型持久性的充分条件．对于该模型的周期系统,在一定的条件下,将产生唯一一个全局渐近稳定的周期正解．对更具普遍意义的概周期现象,也得出了概周期正解唯一存在且全局渐近稳定性的充分条件．     

生态学中一类n维反应扩散方程组解的性质

本文讨论一类不满足所谓的拟单调条件的反应扩散方程组的初边值问题．应用谱论和单调性方法证明了问题解的存在唯一性和平衡解的渐近稳定性．并进一步讨论了生态学中n种群单食物链模型的第二初值问题,得到了问题的非负平衡解的存在性和渐近性以及相应的吸引区域．     

一类害虫与天敌模型的稳定性

本文研究一类害虫——天敌模型的稳定性,得到系统（E）的正常数平衡点为渐近稳定的充分条件,发展了文献[1],[2]的结果．     

具有垂直传染和时滞的肺结核传染病模型

建立了一类含时滞具有垂直传染的肺结核传染病模型,得到了系统的基本再生数R_0.利用平衡点处的特征方程讨论平衡点的局部渐近稳定性;通过构造Lyapunov函数讨论地方病平衡点的全局渐近稳定性;运用比较定理和分析的方法得到无病平衡点的全局渐近稳定性和地方病平衡点的持久性;最后利用数值模拟分析了时滞在模型中的影响.     

基于路径依赖视角的公立医院税制问题研究

“营业税改为增值税”全面实施以来,引起了学者的广泛关注。本文在路径依赖视角下初步探讨了“营改增”对我国公立医院税收制度的影响。简单分析了我国公立医院税制的发展历程以及现状和存在的问题,最后从政策法规、医院内部管理等方面提出一系列完善我国公立医院税收问题的对策。     

碳税和硫税治理下中国未来的碳排放趋势

基于气候治理背景,计算模拟了征收碳税和硫税后的经济影响和减排效果。结果发现,基准情景下,中国经济将保持不断增长的趋势,到2100年,GDP总量将达到69.95万亿美元,碳排放呈现环境库兹涅茨曲线特征,高峰值出现在2034年,碳排放高峰为3832Mt C。在收税治理策略下,无论单独征收硫税还是单独征收碳税,我国的GDP均会受到影响,碳排放都会减少。同时征收碳税和硫税,碳排放显著降低,碳排放高峰出现在2031年,峰值估计为3111Mt C,较基准情景下碳排放高峰降低了721Mt C,高峰值出现的年份也提前了3a,完全满足2030年左右实现碳高峰的承诺。     

Economic aspects of tobacco use and taxation policy.

Tax levels have important effects on cigarette prices and tax revenues. Over 70p of every pound spent on tobacco goes to the Chancellor of the Exchequer, yielding over 5 billion pounds. But the value of tobacco tax revenues have generally fallen--by 1986 they were 10% lower than at their peak in 1965, and tobacco revenue is becoming a smaller proportion of total tax receipts. The impact of a consistent increase in tobacco taxation is important in terms of reduced consumption (and harm to health) as well as in terms of reduced employment. Revenue may, however, increase in the short term. Finally, if the findings of Townsend and Atkinson et al (see above) still apply then the distributive effects of increased taxation on the poor might be less than is sometimes feared.     

Taxpayers,Thieves, and the State: Fiscal Citizenship in Contemporary Italy

As, burdened by its massive public debt, the Italian state nears the verge of default, the debate on taxation and distribution raging in this country's public sphere provides citizens with a means to conceptualize their responsibilities and rights vis-à-vis the state as well as each other. Italian fiscal citizenship thus emerges as an unstable relational category that is negotiated along and across the split between the rhetoric of fiscal and distributive fairness on the one hand, and its actual denial on the other. By fostering the breakdown of solidarity and the intensification of ethnic chauvinism, the failure to implement equity in taxation and distribution shows the extent to which the Italian state is implicated in the divisiveness of social categories that cast each other as an impediment to the fulfillment of their respective rights.     

A cost–benefit analysis of the environmental taxation policy in China: A frontier analysis‐based environmentally extended input–output optimization method

China's high‐speed economic development and reliance on overconsumption of natural resources have led to serious environmental pollution. Environmental taxation is seen as an effective economic tool to help mitigate air pollution. In order to assess the effects of different scenarios of environmental taxation policies, we propose a frontier‐based environmentally extended input–output optimization model with explicit emission abatement sectors to reflect the inputs and benefits of abatement. Frontier analysis ensures policy scenarios are assessed under the same technical efficiency benchmark, while input–output analysis depicts the wide range of economic transactions among sectors of an economy. Four scenarios are considered in this study, which are increasing specific tax rates of SO₂, NO_x, and soot and dust separately and increasing all three tax rates simultaneously. Our estimation results show that: raising tax rates of SO₂, NO_x, and soot and dust simultaneously would have the highest emission reduction effects, with the SO₂ tax rate making the greatest contribution to emission reduction. Raising the soot and dust tax rate is the most environmentally friendly strategy due to its highest abatement to welfare through avoided health costs. The combination of frontier analysis and input–output analysis provides policy makers a comprehensive and sectoral approach to assess costs and benefits of environmental taxation.     

Taxes and the tobacco wars

In this issue (see pages 187 to 191) Dr. Vivian H. Hamilton and associates demonstrate that tax reductions introduced in 5 Canadian provinces in 1994 slowed the rate of decline in cigarette consumption in those jurisdictions. Although both reductions and increases in taxation have been shown to influence tobacco consumption, changes in smoking habits must also be understood in the context of battles being waged on other fronts in the tobacco wars. In addition, more finely detailed analyses are needed to determine the impact of taxation and other factors on the smoking habits of specific subgroups of the population, particularly teenagers.     

Growth characteristics of black alder in pure and mixed stands at the southern boundary of its range

The age dynamics of the main taxation characteristics (height, diameter, stand basal area, average and current increment of stock, and total stand productivity) have been analyzed in stands of different types. The influence of admixed species on the formation of the stands is assessed. The expediency of planting pure stands on heavy textured soils of floodplains in the forest steppe has been proven.     

Redistribution Spurs Growth by Using a Portfolio Effect on Risky Human Capital

We demonstrate by mathematical analysis and systematic computer simulations that redistribution can lead to sustainable growth in a society. In accordance with economic models of risky human capital, we assume that dynamics of human capital is modeled as a multiplicative stochastic process which, in the long run, leads to the destruction of individual human capital. When agents are linked by fully redistributive taxation the situation might turn to individual growth in the long run. We consider that a government collects a proportion of income and reduces it by a fraction as costs for administration (efficiency losses). The remaining public good is equally redistributed to all agents. Sustainable growth is induced by redistribution despite the losses from the random growth process and despite administrative costs. Growth results from a portfolio effect. The findings are verified for three different tax schemes: proportional tax, taking proportionally more from the rich, and proportionally more from the poor. We discuss which of these tax schemes performs better with respect to maximize growth under a fixed rate of administrative costs, and the governmental income. This leads us to general conclusions about governmental decisions, the relation to public good games with free riding, and the function of taxation in a risk-taking society.     

Estimated Effects of Different Alcohol Taxation and Price Policies on Health Inequalities: A Mathematical Modelling Study

Introduction

While evidence that alcohol pricing policies reduce alcohol-related health harm is robust, and alcohol taxation increases are a WHO “best buy” intervention, there is a lack of research comparing the scale and distribution across society of health impacts arising from alternative tax and price policy options. The aim of this study is to test whether four common alcohol taxation and pricing strategies differ in their impact on health inequalities.

Methods and Findings

An econometric epidemiological model was built with England 2014/2015 as the setting. Four pricing strategies implemented on top of the current tax were equalised to give the same 4.3% population-wide reduction in total alcohol-related mortality: current tax increase, a 13.4% all-product duty increase under the current UK system; a value-based tax, a 4.0% ad valorem tax based on product price; a strength-based tax, a volumetric tax of £0.22 per UK alcohol unit (= 8 g of ethanol); and minimum unit pricing, a minimum price threshold of £0.50 per unit, below which alcohol cannot be sold. Model inputs were calculated by combining data from representative household surveys on alcohol purchasing and consumption, administrative and healthcare data on 43 alcohol-attributable diseases, and published price elasticities and relative risk functions. Outcomes were annual per capita consumption, consumer spending, and alcohol-related deaths. Uncertainty was assessed via partial probabilistic sensitivity analysis (PSA) and scenario analysis.The pricing strategies differ as to how effects are distributed across the population, and, from a public health perspective, heavy drinkers in routine/manual occupations are a key group as they are at greatest risk of health harm from their drinking. Strength-based taxation and minimum unit pricing would have greater effects on mortality among drinkers in routine/manual occupations (particularly for heavy drinkers, where the estimated policy effects on mortality rates are as follows: current tax increase, −3.2%; value-based tax, −2.9%; strength-based tax, −6.1%; minimum unit pricing, −7.8%) and lesser impacts among drinkers in professional/managerial occupations (for heavy drinkers: current tax increase, −1.3%; value-based tax, −1.4%; strength-based tax, +0.2%; minimum unit pricing, +0.8%). Results from the PSA give slightly greater mean effects for both the routine/manual (current tax increase, −3.6% [95% uncertainty interval (UI) −6.1%, −0.6%]; value-based tax, −3.3% [UI −5.1%, −1.7%]; strength-based tax, −7.5% [UI −13.7%, −3.9%]; minimum unit pricing, −10.3% [UI −10.3%, −7.0%]) and professional/managerial occupation groups (current tax increase, −1.8% [UI −4.7%, +1.6%]; value-based tax, −1.9% [UI −3.6%, +0.4%]; strength-based tax, −0.8% [UI −6.9%, +4.0%]; minimum unit pricing, −0.7% [UI −5.6%, +3.6%]). Impacts of price changes on moderate drinkers were small regardless of income or socioeconomic group. Analysis of uncertainty shows that the relative effectiveness of the four policies is fairly stable, although uncertainty in the absolute scale of effects exists. Volumetric taxation and minimum unit pricing consistently outperform increasing the current tax or adding an ad valorem tax in terms of reducing mortality among the heaviest drinkers and reducing alcohol-related health inequalities (e.g., in the routine/manual occupation group, volumetric taxation reduces deaths more than increasing the current tax in 26 out of 30 probabilistic runs, minimum unit pricing reduces deaths more than volumetric tax in 21 out of 30 runs, and minimum unit pricing reduces deaths more than increasing the current tax in 30 out of 30 runs). Study limitations include reducing model complexity by not considering a largely ineffective ban on below-tax alcohol sales, special duty rates covering only small shares of the market, and the impact of tax fraud or retailer non-compliance with minimum unit prices.

Conclusions

Our model estimates that, compared to tax increases under the current system or introducing taxation based on product value, alcohol-content-based taxation or minimum unit pricing would lead to larger reductions in health inequalities across income groups. We also estimate that alcohol-content-based taxation and minimum unit pricing would have the largest impact on harmful drinking, with minimal effects on those drinking in moderation.     

Youth are more sensitive to price changes in cigarettes than adults

Virtually all smoking begins in our population's youth and remains as a habit into those smokers' elder years. If we desire to halt smoking in its infancy, we should seek to deter and induce cessation in the youth years. It has been cited that taxation is an effective means to deter smoking at all ages, particularly efficacious in the youth population. This paper explores the merits of this method of preventative medicine, and intends to investigate differences between the price elasticity of cigarette demand between various cohorts, particularly the adult versus the youth population. We use a two-variable log-log, ordinary least-squares econometric regression to determine the extent that price alterations have on participation rates and quantity smoked. Our results show that youth are quite responsive to price increases showing a decrease of 14 percent prevalence in smoking for a 10 percent increase in price; whereas, the adult population is relatively less responsive to such price changes, exhibiting nearly a 2 percent decrease in prevalence for a 10 percent increase in price. We conclude that taxation is an effective means of socially-enacted preventative medicine in deterring youth smoking.