Gaids: a generalised version of the almost ideal demand system

AIDS is a popular model in empirical demand literature. In this paper a generalised version of AIDS (GAIDS) is presented, estimated and statistically tested. Evidence from Italian household data suggests rejection of AIDS, also when demographic effects are considered.     

Radionuclide esophageal transit test: Detection of esophageal dysmotility and reflux in noncardiac chest pain

Thirty-one patients with substernal chest pain but with normal coronary angiographic findings and 25 normal volunteers were included in our study. Esophageal motility—including esophageal mean transit time (MTT), residual fraction (RF), and retrograde index (RI) of the two groups—were evaluated by the radionuclide esophageal transit test. The results showed that among patients with noncardiac chest pain (NCP), 48% have a longer MTT, 39% have a higher RF, and 58% have a higher RI than normal volunteers. We found that esophageal disorders are a common source of noncardiac chest pain, and that radionuclide esophageal transit test is a simple noninvasive screening method to detect esophageal dysmotility or gastroesophageal reflux in such cases.     

Esophageal calcification after corrosive injury

A clinically silent case of intramural esophageal calcification secondary to corrosive injury is presented. Computed tomography (CT) demonstrated a circular calcified esophageal wall over a distance of 5 cm leaving a residual esophageal lumen of 5 mm.     

和胃解毒汤治疗食道癌患者的疗效和安全性

目的探讨和胃解毒汤治疗食道癌患者的疗效以及安全性,为临床治疗食道癌提供新思路。方法选取2019年1月至2020年5月梅州市人民医院收治的食道癌患者62例作为研究对象,按照不同的治疗方案分为对照组(30例)和试验组(32例)。对照组给予调强适形放射治疗加紫杉醇(TXL)联合洛铂(LBP)化疗,即TP化疗方案;试验组在对照组基础上加用和胃解毒汤。比较分析两组患者的治疗效果,并评价两组患者的胃肠道不良反应发生情况。结果试验组治疗有效率及疾病控制率分别为78.13%和87.50%,显著高于对照组的53.33%和66.67%,差异有统计学意义(P<0.05);主要不良反应为胃肠道反应,以恶心呕吐、食欲下降为主,可耐受,其中试验组胃肠道不良反应发生率9.38%,显著低于对照组的30.00%(P<0.05)。结论和胃解毒汤在食道癌患者综合治疗中具有良好的疗效,减轻了不良反应,对治疗食道癌有积极的意义。     

Time-varying parameters in the almost ideal demand system and the Rotterdam model: will the best specification please stand up?

This article assesses the ability of the Rotterdam Model (RM) and of three versions of the Almost Ideal Demand System (AIDS) to recover the time-varying elasticities of a true demand system and to satisfy theoretical regularity. Using Monte Carlo simulations, we find that the RM performs better than the linear-approximate AIDS at recovering the signs of all the time-varying elasticities. More importantly, the RM has the ability to track the paths of time-varying income elasticities, even when the true values are very high. The linear-approximate AIDS, not only performs poorly at recovering the time-varying elasticities but also badly approximates the nonlinear AIDS.     

Estimation of an effectively globally regular demand system: An application to United States meat consumption

A combination of Cooper and McLaren's modified almost ideal demand system (AIDS) and Moschini's semiflexible AIDS specification gives an effective globally regular demand system. Using the United States meat price and consumption data, the effectively globally regular demand system was estimated and compared to Cooper and McLaren's modified AIDS. The Likelihood Dominance Criterion showed that Cooper and McLaren's modified AIDS was actually better model than the effectively globally regular demand system proposed. The reason may be due to the fact that the violation of the curvature conditions is not significant for the given data. First Version Received: September 1998/Final Version Received: April 2001     

Economic Development,Risky Sexual Behavior,and AIDS Epidemics—Theory and Evidence

In this paper, we present a simple theoretical model to investigate how economic development affects AIDS epidemics through its influence on individuals’ sexual behavior, building on the literature on economic growth with endogenous mortality concern. We employ provincial data from China on the incidence rate of AIDS between 2002 and 2008 to test the theoretical predictions. The findings are: (1) a rise in personal income/wealth induces more safe sexual activities and reduces the prevalence of AIDS; and (2) increases in public health expenditure do not have a significant positive impact on individuals’ preference of risky sexual activity over safe sexual activity.     

中国艾滋病预防控制的政策研究

有关艾滋病预防和控制的研究既是一项政策性很强的社会系统研究，同时也是一项需要多学科间进行合作的应用性研究。艾滋病预防控制主要可分为基础性研究；综合性研究；检测和监测；宣传、教育和行为干预；治疗、咨询和社会支持这五个方面。本文在分析以上五个方面之间以及每个方面的各个要素之间存在的相互关系的基础上，结合泰国经验和教训。对中国艾滋病预防控制政策进行了系统研究，并提出一些政策性建议。     

The demand for home-produced and imported alcoholic beverages in Cyprus: the AIDS approach

The purpose of this paper is to investigate the demand and its composition between home-produced and imported for alcoholic beverages in Cyprus. The methodological approach used is the Almost Ideal Demand System (AIDS), both in static and dynamic terms. Empirically, the AIDS, both in its static and dynamic version, was estimated using time-series (1970-1992) for three sets of data which include: (1) alcoholic beverages (wine-beer-other brandies) broken down between home-produced and imported (model A); (2) alcoholic beverages only without disaggregation between home-produced and imported (model B), and (3) aggregate alcoholic beverages (wine-beer-other brandies) and food (model C). Zellner's iterative estimation procedure was used for estimating the model. The empirical findings: (1) strongly support the dynamic version of the AIDS over its static alternative; and (2) provide certain guidelines concerning economic policies relating to an increase in government revenues and changing the composition between home-produced and imported consumption of alcoholic beverages. These basic findings could be considered relevant to the policy makers in the light of Cyprus' accession to the EU.     

Social science research on AIDS in Africa: questions of content,methodology and ethics

An international symposium on the social sciences and AIDS in Africa was held in Sali Portudal, Senegal, in November 1996. English- and French-speaking researchers and AIDS activists came together to consider a broad range of topics, with reference to individual country experience. The authors review some of the issues discussed at the symposium; in particular, the need for more social science research on AIDS to reconsider and re-evaluate methodologies and their role in relation to interventions, the variety of discourses through which AIDS is articulated and understood, and ethical questions relating to confidentiality and disclosure, as well as international disparities in income and access to resources. The shift in perception and understanding about the significance of AIDS, with its implications for the weakening of a former sense of common purpose, makes conferences such as this one all the more important.     

AIDS mortality and its effect on the labor market: Evidence from South Africa

This paper investigates how HIV/AIDS has impacted the labor market in South Africa, focusing on its effect on wages and employment. This is done by matching individual level data with group specific cumulative AIDS mortality rates. Exploiting the panel nature of the data, I remove individuals whose productivity is most likely impacted by HIV/AIDS, and find evidence that cumulative AIDS mortality has led to reductions in wages of between 3 and 6% for the African population group (Black South Africans). Furthermore, I also find evidence that the epidemic has lowered employment in South Africa. This result is concentrated among those with the lowest levels of education and employment. Although not large in magnitude, these effects are widespread across a significant portion of the population, contributing to a substantial loss of income throughout the South African economy.     

How much of a threat to economic growth is a mature AIDS epidemic?

The article models the impact on economic growth of HIV/AIDS when the epidemic is in a mature phase, in contrast with previous studies focused on periods of expansion as it is typically the case in African countries. Simulations for Honduras, the epicentre of the epidemic in Central America, show that AIDS is not likely to threaten economic growth neither through labour nor capital accumulation channels. Impacts are estimated between 0.007 and 0.27% points of Gross Domestic Product (GDP) growth annually for the period 2001 to 2010. Increasing spending on prevention, higher public treatment subsidies and increasing treatment access will not jeopardize economic growth prospects. Critical factors that slash economic growth in Africa (such as human capital reductions and shifts in relative skills) are not strong in Honduras.     

HIV/AIDS AND BANKING STABILITY IN DEVELOPING COUNTRIES

We argue that the recent large increase in deposits’ turnover in many developing countries with high HIV/AIDS prevalence is associated with the spread of the disease. The point is that the need to pay for individual treatments force large‐scale withdrawals of households’ deposits, and that those large withdrawals put the banking industry at risk. In a standard demand‐deposit model where the HIV/AIDS prevalence among depositors is random, we show that (1) the probability of a large‐scale banking failure without a bank run increases as the odds of any prevalence level increases, and (2) it is always optimal to deposit, and thus to accept the risk of banking failure, to maintain long‐term investments in place.     

Assessing the impact of AIDS on the growth path of the Malawian economy

More than 1% of people of sub-Saharan Africa aged 15-49 years are infected with HIV, with over half likely to develop AIDS in the next decade. As rates of HIV infection continue to climb, there will be staggering financial consequences to bear in the years ahead in terms of high medical treatment costs and crippled macroeconomies. The authors employ a modified Solow growth model to simulate the impact of the AIDS epidemic on output capacity and other key macroeconomic aggregates in Malawi. They compare a counterfactual no-AIDS scenario to medium and extreme AIDS projections and find that average real GDP growth over the 1985-2010 period will be 0.2-0.3 percentage points lower in the medium case and 1.2-1.5% lower in the extreme case relative to the no-AIDS case. The size of the economy by 2010 will therefore be reduced from a real GDP of 5.03 billion (constant 1985) Kwacha without AIDS to 4.81-4.77 and 3.80-3.46 billion Kwacha in the medium and extreme scenarios, respectively.     

Imposing local curvature in the QUAIDS

In this paper, we build on Ryan and Wales (1998), Moschini (1999), and Serletis and Shahmoradi (2007) and impose curvature conditions locally on the quadratic Almost Ideal Demand System (AIDS) model of Banks et al. (1997), an extension of the simple AIDS model of Deaton and Muellbauer (1980) that can generate quadratic Engel curves [that is, rank-three demand systems, in the terminology of Lewbel (1991)]. In doing so, we exploit the Slutsky matrix of second order derivatives of the indirect utility function.     

The HIV Epidemic,Skill Heterogeneity,and Output

This paper investigates the effect of HIV/AIDS on output using an overlapping generations model with heterogeneous agents calibrated to sub‐Saharan Africa. Output is found to be below a no‐AIDS output in a range between 3% (10%), when only unskilled workers are affected, and 10% (28%), when only skilled workers are affected, whenever the overall infection rate is 7% (20%). When investigating the hypothesis that AIDS affects skilled workers more severely than unskilled at the beginning of the epidemic, with the effect switching as the epidemic becomes more mature, the findings are that the economy can be 8% smaller along the transition path. In all scenarios where the epidemic is temporary, it would take four to five generations or about 90 years for sub‐Saharan Africa to recover.     

Pricing and patents of HIV/AIDS drugs in developing countries

This article provides empirical evidence on the impact of patents on drug prices across developing countries. It uses sales data on human immunodeficiency virus (HIV)/acquired immuno deficiency syndrome (AIDS) drugs in a sample of 34 low- and middle-income countries between 1995 and mid-2000. The main findings are that patents do shift drug prices up, drug prices are correlated to per capita income levels and drug firms follow a skimming strategy when pricing new HIV/AIDS drugs. That is, there is across country and intertemporal price discrimination in the global drug markets.     

AIDS crisis and growth

We investigate an OLG economy where an AIDS epidemic influences human capital accumulation and growth through the creation of large numbers of orphans. We study how intra-family allocations regarding school and work time of children are adjusted in the face of AIDS within a family, and how, in turn, these adjustments influence accumulation of physical and human capital. We compute the aggregate effects of an AIDS epidemic on human and physical capital accumulation and growth. We find that growth effects of an AIDS epidemic are large. Some policies such as subsidization of AIDS medication have relatively small effects.     

Regression analysis on the variation in efficiency frontiers for prevention stage of HIV/AIDS

Abstract

Objectives:

To investigate how the cost effectiveness of preventing HIV/AIDS varies across possible efficiency frontiers (EFs) by taking into account potentially relevant external factors, such as prevention stage, and how the EFs can be characterized using regression analysis given uncertainty of the QALY-cost estimates.

Methods:

We reviewed cost-effectiveness estimates for the prevention and treatment of HIV/AIDS published from 2002–2007 and catalogued in the Tufts Medical Center Cost-Effectiveness Analysis (CEA) Registry. We constructed efficiency frontier (EF) curves by plotting QALYs against costs, using methods used by the Institute for Quality and Efficiency in Health Care (IQWiG) in Germany. We stratified the QALY-cost ratios by prevention stage, country of study, and payer perspective, and estimated EF equations using log and square-root models.

Results:

A total of 53 QALY-cost ratios were identified for HIV/AIDS in the Tufts CEA Registry. Plotted ratios stratified by prevention stage were visually grouped into a cluster consisting of primary/secondary prevention measures and a cluster consisting of tertiary measures. Correlation coefficients for each cluster were statistically significant. For each cluster, we derived two EF equations – one based on the log model, and one based on the square-root model.

Discussion:

Our findings indicate that stratification of HIV/AIDS interventions by prevention stage can yield distinct EFs, and that the correlation and regression analyses are useful for parametrically characterizing EF equations. Our study has certain limitations, such as the small number of included articles and the potential for study populations to be non-representative of countries of interest. Nonetheless, our approach could help develop a deeper appreciation of cost effectiveness beyond the deterministic approach developed by IQWiG.