随机利率影响下信用风险的Monte—Carlo模拟

在前人利用马尔科夫链表示公司信用等级的基础上，将信用等级和随机利率引入离散时间的信用风险模型中，从而提出随机利率影响下的新的信用风险模型。就上述模型，对不同初始信用等级、初始盈余以及不同时刻的破产概率进行Monte—Carlo模拟，并讨论了相同条件下初始盈余与破产概率、初始信用等级与破产概率以及时间长短与破产概率之间的相互关系。     

出口信用保险对我国出口贸易影响的实证分析

出口作为拉动经济发展的＂三驾马车＂之一,在我国经济发展中起到举足轻重的作用,为了促进出口贸易的发展,我国实施了多项出口贸易鼓励政策。本文对出口退税、出口信用保险、出口贸易三个变量进行协整分析,并通过VAR模型估计以及脉冲响应函数及方差分解的实证分析,得出三个变量的相互关系;同时通过两个因素的实证比较,得出出口信用保险虽然在短期内对出口贸易的影响还不够显著,但从长期看却是显著的,并且要大于出口退税对出口贸易的影响程度,最后提出发展我国出口信用保险的政策建议。     

Economic assessment of doripenem versus imipenem in the treatment of ventilator-associated pneumonia

Abstract

Background: Ventilator-associated pneumonia (VAP), the most common nosocomial infection in critically ill patients, is associated with significantly longer duration of mechanical ventilation, and increased mortality, hospital days, and health-care costs. A previously published prospective, randomized study established the noninferiority of intravenous (IV) doripenem versus IV imipenem/cilastatin (‘imipenem‘) for VAP. This study compares the economic outcomes of IV therapy with doripenem versus imipenem as first-line treatment for VAP.

Methods: A decision-analytic model of inpatient care and outcomes for VAP was used to estimate costs associated with VAP treatment. The model calculates total hospital costs, comprising costs of initial and concomitant therapy, and costs associated with mechanical ventilation, intensive care unit stays, and total days in hospital.

Results: Total treatment costs for doripenem were $10,630 lower than for imipenem ($71,259 vs. 81,889), driven primarily by differences in costs of mechanical ventilation ($45,224 for doripenem, $57,348 for imipenem). Probabilistic sensitivity analyses found doripenem consistently cost saving versus imipenem in 1,000 simulations. Study limitations include use of a simple model to represent a complex disease process and reliance on trial data that may not reflect real-world care and outcomes.

Conclusions: Doripenem is a cost saving first-line treatment for VAP versus imipenem while providing an equivalent rate of cure.     

基于产业链的企业经营指标预测研究及实证分析

客观科学的预测企业主要经济指标是非常重要的,但是比较困难的。采用数学模型是一种有效的科学方法。本文尝试基于产业链,运用计量经济学的方法,使用GDP和行业数据,模拟出数学模型,以此来预测企业的主要经济指标。并以造纸业为例进行实证分析。     

Does interdependency affect firm and industry profitability? an empirical test

Strategy researchers have argued that heterogeneity in firms' practices and profitability within and across industries may derive from industry‐level differences in the extent of interdependencies among firms' activities. Theoretical models have clarified how and why differences in the extent of the interdependencies faced by firms across industries may affect the distributions of firm profits, but the specific predictions from these models have not been empirically tested. In this paper, we present what we believe is the first large scale empirical analysis linking differences in the extent of interdependencies across industries to differences in the distribution of firm profits within and across those industries. We use survey data to measure interdependencies systematically across a wide number of industries, thus addressing the primary obstacle to incorporating interdependencies in larger scale empirical work, and find evidence consistent with the theoretical predictions: average profitability is highest in industries with moderate levels of interdependency; the dispersion of profits among firms is higher in industries with more extensive interdependencies; and industries with more extensive interdependencies have a more positively skewed performance distribution. We find that the effect of interdependencies on average industry profitability is similar in scale to the effect of patent protection and industry growth rates, placing interdependency squarely among the strategy field's central concepts. Copyright © 2009 John Wiley & Sons, Ltd.     

Evolution and challenges of dairy supply chains: Evidence from supermarkets,industries and consumers in Ethiopia

In developing countries the demand for products of animal origin is expected to grow rapidly in the coming years. Using data collected from 200 urban households this study examines the evolution of the dairy market in Ethiopia. In particular, this study suggests that although the Ethiopian dairy market remains extremely thin and volatile, the commercialization of processed dairy products through supermarkets is expanding and is expected to keep doing so in the foreseeable future. Increasing urbanization and corresponding changes in consumer preferences, behaviour and purchasing power are the identified causes for the rise of supermarket-processor dairy chains. This study shows also that emerging dairy chains provide new market opportunities to Ethiopian farmers, but the existence of retail-industrial monopolies and monopsonies jeopardize farmers’ economic benefits to a great extent. The study concludes with some implications for policy and further research.     

What makes countries initiate WTO disputes on food-related issues?

This paper analyses relevant determinants for the probability to initiate a dispute on policy measures under the World Trade Organization (WTO) dispute settlement system. The empirical analysis differs from existing assessments by focusing on agro-food-related disputes and provides a more in-depth analysis of specific country and sectoral characteristics not considered in previous studies. Contrary to recent analyses of overall trade disputes, the results show that some determinants such as legal capacity and monetary means are not statistically significant. Own protectionist behaviour, endured protectionism, and the duration of WTO membership, however, could be identified as relevant determinants with the expected direction of impact.     

Interaction of size,book‐to‐market and momentum effects in Australia

This study seeks to disentangle the effects of size, book‐to‐market and momentum on returns. Initial results show that each characteristic has a role in explaining returns, but that there is interaction between size and momentum, as well as between size and book‐to‐market. Three key findings emerge. First, the size premium is the strongest, particularly in the loser portfolios. Second, the value premium is generally limited to the smallest portfolios. Third, the momentum premium is evident for the large‐ and middle‐sized portfolios, but loser stocks significantly outperform winner stocks in the smallest size portfolio. When these interactions are controlled with multivariate regression, we find a significant negative average relation between size and returns, a significant positive average relation between book‐to‐market and returns, and a significant positive average relation between momentum and returns.     

青岛啤酒物流模式探讨与分析

青岛啤酒招商局物流有限公司（下称青啤招商物流）是＂青啤模式＂的载体。青岛啤酒的物流资产和招商局物流先进的物流管理经验的物流合作模式,被誉为＂青啤模式＂,在国内尚属首创。＂青啤模式＂可以避免国企在物流外包中不可克服的阻力和障碍,在原物流资产和人员持续存在的情况下,实现与专业物流企业双赢的局面,对国内企业特别是国有企业的物流改革有重大示范作用,成为业界和媒体津津乐道的案例。     

The impact of relative residence times on the distribution of heavy drinkers in highly distinct environments

Alcohol consumption is a function of social dynamics, environmental contexts, individuals' preferences and family history. Empirical surveys have focused primarily on identification of risk factors for high-level drinking but have done little to clarify the underlying mechanisms at work. Also, there have been few attempts to apply nonlinear dynamics to the study of these mechanisms and processes at the population level. A simple framework where drinking is modeled as a socially contagious process in low- and high-risk connected environments is introduced. Individuals are classified as light, moderate (assumed mobile), and heavy drinkers. Moderate drinkers provide the link between both environments, that is, they are assumed to be the only individuals drinking in both settings. The focus here is on the effect of moderate drinkers, measured by the proportion of their time spent in “low-” versus “high-” risk drinking environments, on the distribution of drinkers.A simple model within our contact framework predicts that if the relative residence times of moderate drinkers are distributed randomly between low- and high-risk environments then the proportion of heavy drinkers is likely to be higher than expected. However, the full story even in a highly simplified setting is not so simple because “strong” local social mixing tends to increase high-risk drinking on its own. High levels of social interaction between light and moderate drinkers in low-risk environments can diminish the importance of the distribution of relative drinking times on the prevalence of heavy drinking.