bluuebunny/crossref_metadata_2025 huggingface dataset:
Dutch Disease and the crime epidemic: an investigation of the mineral boom in Papua New Guinea
Authors: Chand Satish , Levantis Theodore
Published: March 2003

Papua New Guinea has pinned its hopes for economic development on its mineral wealth but, so far, this has been a false promise. Given Papua New Guinea’s vulnerability, this raises questions of a Dutch Disease effect. Dutch Disease is dismissed in principle, but an appreciating real exchange rate is considered to have important offsetting economic consequences via its implications for crime. Using a CGE model incorporating crime as an economic activity, the contribution to welfare of a resources boom is investigated. The results confirm that a resources boom will deliver a net welfare benefit, but far smaller than the revenues generated would suggest, and at a cost to equity.
Research returns redux: a meta‐analysis of the returns to agricultural R&D
Authors: Alston Julian M. , Marra Michele C. , Pardey Philip G. , Wyatt T. J.
Published: March 2003

A total of 289 studies of returns to agricultural R&D were compiled and these provide 1821 estimates of rates of return. After removing statistical outliers and incomplete observations, across the remaining 1128 observations the estimated annual rates of return averaged 65 per cent overall — 80 per cent for research only, 80 per cent for extension only, and 47 per cent for research and extension combined. These averages reveal little meaningful information from a large body of literature, which provides rate‐of‐return estimates that are often not directly comparable. This study was aimed at trying to account for the differences. Several features of the methods used by research evaluators matter, in particular assumptions about lag lengths and the nature of the research‐induced supply shift.
Beef import market shares in Taiwan: implications for Australia
Authors: Chang Hui‐Shung (Christie) , Hsia Chung‐Jen
Published: March 2003

Market shares of major beef suppliers to Taiwan, including Australia, the United States and New Zealand, were estimated econometrically to determine their relative competitiveness. The analysis, based on monthly data from June 1990 to August 1997, showed that relative prices and consumer incomes were important factors influencing suppliers’ market shares. Specifically, the demand for Australian beef responded little to an increase in price and negatively to an increase in consumer income. Furthermore, the growth in Taiwan beef consumption has slowed down and Australian beef suppliers need to re‐assess the market potential and develop appropriate marketing strategies to maintain competitiveness.
Valuing remnant vegetation in Central Queensland using choice modelling
Authors: Blamey Russell , Rolfe John , Bennett Jeff , Morrison Mark
Published: March 2003

In the Desert Uplands region of Central Queensland, many pastoralists are clearing vegetation in order to improve cattle grazing production. A choice modelling study was undertaken to provide estimates of the benefits of retaining remnant vegetation that are appropriate for inclusion in a cost benefit analysis of tighter clearing restrictions. Attributes included in the choice model were reductions in the population size of non‐threatened species, the number of endangered species lost to the region, and changes in regional income and employment. A nested logit model was used to model the data in order to avoid violations of the independence of irrelevant alternatives condition. The estimated benefits are reported for several tree clearing policy regimes that are more stringent than those currently applied.
Agriculture’s ‘multifunctionality’ and the WTO
Authors: Anderson Kym
Published: March 2003

Are the agricultural policy reforms embodied in the Uruguay Round consistent with meeting domestic policy objectives such as providing adequate food security, environmental protection and viability of rural areas? This article examines the claim that agriculture deserves more price support and import protection than other sectors because of the non‐marketed externalities and public goods it produces jointly with marketable food and fibre (agriculture’s so‐called ‘multifunctionality’). Do these unrewarded positive externalities exceed the negative externalities from farming by more than the net positive externalities produced by other sectors? To what extent are those farmer‐produced spillovers under‐supplied, and what are the most efficient ways to boost their production to the socially optimal levels? The article concludes that there is little trade‐off required to meet domestic policy objectives on the one hand and agricultural protection reform objectives as embodied in WTO rules on the other.
The application of trade and growth theories to agriculture: a survey
Authors: Van Berkum Siemen , Van Meijl Hans
Published: March 2003

This article reviews a broad range of theoretical concepts available to explain international trade in agricultural and food products. For many years agricultural trade analyses were largely based on traditional perceptions of comparative advantage following neoclassical theory. Observations of agricultural trade suggest, however, that concepts from modern trade and growth theories are increasingly relevant. This survey demonstrates that many opportunities exist for applying these new theories to the modern food economy.
Transition, development and the supply of wheat in China
Authors: Rozelle Scott , Huang Jikum
Published: March 2003

The overall goal of this article is to better understand the factors that influence China’s wheat supply. We assess trends in China’s wheat output and develop a framework to measure the relationship between output and key determinants of China’s wheat sector growth. Elasticity estimates and factor growth trends help decompose the growth of reform‐era wheat supply into its component parts. The results show that growth in the early reform period was due to institutional change and technology. In the late reform period, however, with the returns to institutional change exhausted, all of China’s growth in wheat supply was due to technology, a result that implies China’s government should invest heavily in agricultural research and development.
Agricultural extension policy in Australia: the good, the bad and the misguided
Authors: Marsh Sally P. , Pannell David
Published: March 2003

In most states of Australia, agricultural extension policies and practices have increasingly been based on considerations of private/public goods, user pays and cost recovery. In addition, the delivery of extension has been strongly influenced by changing administrative structures and a change in the paradigm within which the extension community operates. These changes have had major impacts, including more extension being delivered by the private sector. There are positive aspects to the changes and, for some issues, they are appropriate. However, we have a number of reservations, particularly about the effectiveness of current extension systems in assisting the adoption of complex environmental and farming system technologies.
Elegy, ode or panegyric? Practising agricultural economics in Australia, 1975–99
Authors: Godden David
Published: March 2003

Changes are investigated in the Australian agricultural economics profession, 1975–99, using a conventional microeconomics framework of supply and demand for agricultural economists. Aggregate exogenous factors such as changes in the agricultural and tertiary education sectors, and changes in beliefs about the proper role of government, have changed both supply and demand conditions for agricultural economists. The profession has responded by shifting its focus away from narrowly agricultural policy, especially marketing policy, towards areas of market failure such as environmental and natural resource issues.
Environmental economics and the Murray–Darling river system
Authors: Quiggin John
Published: March 2003

Much concern about the negative environmental consequences of agricultural development in Australia, including salinisation, waterlogging and algal blooms, has focused on the problems of the Murray–Darling Basin. The aim of this article is to provide an overview of the environmental problems of the Murray–Darling Basin from an economic perspective, and a selective survey of the relevant economic literature, including theoretical analysis, modelling and contributions to the development of water policy. In attempting to understand the complex problems of the Murray–Darling Basin, an eclectic approach drawing on externality, sustainability and property rights perspectives seems most appropriate.
The politics and economics of wool marketing, 1950–2000
Authors: Richardson Bob
Published: March 2003

The history of marketing, research, development policies and intervention in marketing of the wool clip is reviewed from the perspective of an insider. The overall theme is that politics took over comprehensively from clear economic policy advice on wool marketing in the past 50 years and woolgrowers paid a high price for this. The idea of ‘integrated marketing’ including an export monopoly, a buffer stock scheme and coordinated promotion and R&D, collectively a strong interventionist philosophy, has waxed and waned. Having borne most of the costs of these failed policies, remaining woolgrowers can now look forward to a market less distorted by political interference.
Does consistent aggregation really matter?
Authors: Shumway C. Richard , Davis George C.
Published: March 2003

Consistent aggregation ensures that behavioural properties which apply to disaggregate relationships apply also to aggregate relationships. The agricultural economics literature which has tested for consistent aggregation or measured statistical bias and/or inferential errors due to aggregation is reviewed. Tests for aggregation bias and errors of inference are conducted using indices previously tested for consistent aggregation. Failure to reject consistent aggregation in a partition did not entirely mitigate erroneous inference due to aggregation. However, inferential errors due to aggregation were small relative to errors due to incorrect functional form or failure to account for time series properties of data.
An economic analysis of farm forestry as a means of controlling dryland salinity
Authors: Cacho Oscar , Greiner Romy , Fulloon Lachlan
Published: March 2003

Large areas of agricultural land under conventional crops and pastures are at risk of dryland salinisation in Australia. The salinisation problem can be controlled by strategic and large‐scale planting of trees; however, farm forestry enterprises evaluated with conventional discounting techniques do not generally rank as an attractive alternative to annual crops on productive land. In this article, an optimal control model that explicitly accounts for decline or improvement in land quality over a period of 40 years is presented. The optimal area planted to trees and the optimal groundwater‐table trajectory through time are determined under a variety of scenarios. Implications of the results for policy design are discussed.
Cost and trade impacts of environmental regulations: effluent control and the New Zealand dairy sector
Authors: Cassells Sue M. , Meister Anton D.
Published: March 2003

New Zealand legislation sets standards for water quality. Nitrogen leaching from dairy effluent compromises these standards, with the consequent move being toward land‐based effluent disposal. The cost of this to the dairy sector was estimated and a Computable General Equilibrium (CGE) model (GTAP) was used to investigate the impact of additional production costs on NZ’s dairy export trade. Two scenarios were analysed: first, NZ acts unilaterally in imposing water quality regulations, second, the other principal dairy exporters act in a similar fashion. Changes in trade patterns vary from insignificant to large, depending on the scenario analysed.
Charging for the use of plant varieties
Authors: Kingwell Ross
Published: March 2003

Private and many publicly funded plant breeding organisations charge farmers for use of varieties they develop. This article compares four alternative charging mechanisms and outlines responses to these alternatives by farmers and plant breeders. Risk‐averse farmers and breeders are shown to have opposite preferences for charging mechanisms. Results suggest profit‐based or ad valorem royalties are preferred by farmers whereas breeders prefer area or tonnage‐based royalties. Risk‐sharing arrangements between both parties could lead to an overall preference for profit‐based or ad valorem royalties. However, this finding is subject to important caveats and practical limitations.
Pricing‐to‐market in NSW rice export markets
Authors: Griffith Garry , Mullen John
Published: March 2003

The Ricegrowers’ Cooperative Limited is a single‐desk seller of NSW Japonica rice on the export market. Confidential monthly price data supplied by the Cooperative were used to examine ‘pricing‐to‐market’ in four of its major export markets. The hypothesis of a competitive market was rejected. The Cooperative has been able to vary mark‐ups over different markets and with respect to the importer’s currency in each market. The exchange rate results in particular suggest that the Cooperative has been able to exercise market power to obtain price premiums.
Changes in regional inequality in rural China: decomposing the Gini index by income sources
Authors: Wan Guang Hua
Published: March 2003

A new method is proposed to decompose inequality changes as measured by the Gini index into structural effects, real inequality effects and interactive effects. Application of the method to updated Chinese data reveals that structural effects represent the driving force underlying the increasing trend in regional income inequality in rural China. Policy implications are explored. In addition to these contributions, considerable efforts are made to construct the income data used in the article. Pitfalls in measuring income inequality in rural China are discussed.
Macroeconomic impacts of export commodity price subsidy in Papua New Guinea
Authors: Kannapiran Chinna A.
Published: March 2003

A macroeconometric simulation study is undertaken to evaluate the impacts of a price subsidy for tree crops in Papua New Guinea (PNG). The price subsidy had favourable impacts on tree crop export income, aggregate demand, private consumption, and investment and employment. It increased imports, the budget deficit, and the demand for money and adversely affected the fiscal balance, inflation and interest rates, the BOP position and macroeconomic stability. The price subsidy contributed favourably to internal balance but adversely affected external balance. It worked against many of the policy objectives and made macroeconomic management difficult. With the introduction of the price subsidy, the government violated the commitments made under the Uruguay Round Agreement on Agriculture and PNG’s Structural Adjustment Program.
Incentives and static and dynamic gains from market reform: rice production in Vietnam
Authors: Che Tuong Nhu , Kompas Tom , Vousden Neil
Published: March 2003

This article develops a dynamic model to account for the enhanced incentive effects that result from market reform through a move toward private property rights and competitive markets. Reform is captured through an emerging profits function which depends on effective prices and incentives to work harder. Static and dynamic output gains from reform are derived through increases in total factor productivity and induced capital accumulation. The model is applied to rice production in Vietnam over the period 1976–94. The more extensive is market reform, the larger the effects found on rice output, the capital stock and transitional growth rates, suggesting that incentives and more competitive markets matter greatly.
Earmarking of pollution charges and the sub‐optimality of the Pigouvian tax
Authors: Jiang Tingsong
Published: March 2003

One approach to internalising a negative externality of economic activity is to impose a Pigouvian tax equal to the marginal cost of the externality. However, this approach overlooks the possibility that the tax revenue can be earmarked to correct the externality directly, i.e. financing the environmental protection projects. It is found that a pure Pigouvian tax is usually not an optimal policy. This issue is examined in both partial and general equilibrium, static and dynamic settings. Certain conditions for justifying a pure Pigouvian tax or a fully earmarked tax scheme are developed.
The citizen versus consumer hypothesis: Evidence from a contingent valuation survey
Authors: Curtis John A. , McConnell Kenneth E.
Published: March 2003

This paper examines the criticism of contingent valuation put forth by Blamey, Common and Quiggin (Australian Journal of Agricultural and Resource Economics, 1995, vol. 39, pp. 264–288). They argue that households have consistent preferences over private goods but not jointly consistent preferences over public and private goods and, hence, contingent valuation cannot uncover meaningful responses for the valuation of public goods. In this paper we argue that the motives that are manifested in choices for public goods can be explained in two ways. One is the model of the citizen, proposed by Blamey et al. (1995). The second is a model of neoclassical preferences with altruism. Given these alternative and competing explanations of choices for public goods, what matters is whether they imply differences in willingness to pay for public goods. We provide statistical evidence from a contingent valuation study of the control of deer in the USA that there is no difference in willingness to pay between those who profess ‘citizen’ or altruistic preferences and the rest of the presumably purely private respondents.
Transgenic varieties and productivity of smallholder cotton farmers in China
Authors: Huang Jikun , Hu Ruifa , Rozelle Scott , Qiao Fangbin , Pray Carl E.
Published: March 2003

Genetically modified cotton varieties have greater production efficiency for smallholders in farming communities in China. We also find that the adoption of Bacillus thuringiensis (Bt) cotton varieties leads to a significant decrease in the use of pesticides. Hence, we demonstrate that Bt cotton appears to be an agricultural technology that improves both production efficiency and the environment. In terms of policies, our findings suggest that the government should investigate whether or not they should make additional investments to spread Bt to other cotton regions and to other crops.
Taxes and quality: A market–level analysis
Authors: James Jennifer , Alston Julian
Published: March 2003

A conventional assumption of product homogeneity when the commodity of interest is actually heterogeneous will lead to errors in an analysis of the incidence of policies, such as taxes. In this article, an equilibrium displacement model is used to derive analytical solutions for price, quantity, and quality effects of ad valorem and per unit taxes. The results show how parameters determine the effects of tax policies on quality. The potential for tax–induced distortions in quality, and the distributive consequences of those distortions, are illustrated in a case study of the market for Australian wine.
Market power analysis in the retail food industry: a survey of methods
Authors: Digal Larry N. , Ahmadi–Esfahani Fredoun Z.
Published: March 2003

The present paper surveys various methods used to analyse market power in the retail food industry. The strengths and weaknesses of these approaches are explored and a review of the issues in using New Empirical Industrial Organization (NEIO) and time–series models is provided. The absence of a theory underlying time–series models is highlighted and a review of some theoretical models in retailing is presented. The impact of imperfect competition in the food processing sector on retailing is also examined. It is argued that a combination of the approaches that minimises the weaknesses and builds on the strengths of single approaches may prove more promising for examining non–competitive behaviour.
The nature of the research‐induced supply shift
Authors: Wohlgenant Michael K.
Published: March 2003

Differences among firms in a competitive industry can affect the shape of the industry supply curve. It is necessary to know how both production costs and rents are affected by research. Industry response to research will be different depending upon whether entry occurs. If the effect of entry is ignored, then the price decline from research will be overstated. Industry marginal returns can be positive with purely yield‐increasing research, even when industry demand is inelastic. Standard formulas for calculating producer surplus based on linear industry supply and demand curves are strictly valid only if the analysis is restricted to short‐run equilibrium behaviour.
Tactical Opportunities, Risk Attitude and Choice of Farming Strategy: an Application of the Distribution Method
Authors: Marshall Graham R. , Jones Randall E. , Wall Lisa M.
Published: March 2003

When assessing farming strategies, it is important to account for the opportunities provided for tactically adjusting to outcomes of risk. The hypothesis that accounting for tactical adjustment is more important than accounting for risk attitude was supported in this study with regard to identifying the optimal drainage recirculation strategy for an irrigated dairy farm. Failing to account for tactical adjustment would lead to a sub‐optimal choice, costing the farmer about A$3 100 in present value terms. In contrast, failing to account for risk aversion would not affect the strategy chosen. The distribution method was found to be well suited to modelling tactical adjustment.
Capturing benefits from water entitlement trade in salinity affected areas: A role for trading houses?
Authors: Bell Rosalyn
Published: March 2003

While there is potential for substantial benefits from water entitlement trade, external effects such as salinity may mean that traders cannot capture these benefits. This paper demonstrates that by creating a trading house as a single seller of water entitlements, with trade profits distributed to buyers, it is possible to achieve an allocation of entitlements which gives a social outcome higher than that possible from atomistic competition for entitlements. Such an outcome may be comparable to an optimally set uniform charge for water entitlements, but the trading house mechanism has the advantage that it makes use of trade to generate information on the optimal level of charging in the presence of salinity.
Trade liberalisation and regional integration: the search for large numbers
Authors: Robinson Sherman , Thierfelder Karen
Published: March 2003

We surveyed the empirical literature using multi–country computable general equilibrium (CGE) models to analyse potential and actual regional trade agreements (RTAs). The studies indicate that these RTAs improve welfare, that trade creation greatly exceeds trade diversion, and that they are consistent with further global liberalisation. The welfare gains are bigger when models incorporate aspects of “new trade theory” such as increasing returns, imperfect competition, and links between trade liberalisation, total factor productivity growth, and capital accumulation. We also conjectured that an RTA expands market size and stability, allowing firms to pursue economies of fine specialisation, generating additional “Smithian” efficiency gains.
World food markets into the 21st century: commodity risk management policies
Authors: Duncan Ron
Published: March 2003

Recent concerns about future global food production seem poorly based. The rapid phase of growth in food consumption is over for most of the world's population because of increased incomes and, besides, population growth rates continue to slow. Thus, the rate of growth of food production needed in the future is much lower than it has been for the past 40 years. Production and price instability will continue, perhaps with lessened intensity because of reduced government intervention. With private agricultural interests now facing greater exposure to price and production risks, especially in developing countries, there needs to be greater emphasis on financial market instruments for managing these risks.
A HIERARCHICAL METHOD FOR FINDING OPTIMAL ARCHITECTURE AND WEIGHTS USING EVOLUTIONARY LEAST SQUARE BASED LEARNING
Authors: GHOSH RANADHIR , VERMA BRIJESH
Published: March 2003

In this paper, we present a novel approach of implementing a combination methodology to find appropriate neural network architecture and weights using an evolutionary least square based algorithm (GALS).1 This paper focuses on aspects such as the heuristics of updating weights using an evolutionary least square based algorithm, finding the number of hidden neurons for a two layer feed forward neural network, the stopping criterion for the algorithm and finally some comparisons of the results with other existing methods for searching optimal or near optimal solution in the multidimensional complex search space comprising the architecture and the weight variables. We explain how the weight updating algorithm using evolutionary least square based approach can be combined with the growing architecture model to find the optimum number of hidden neurons. We also discuss the issues of finding a probabilistic solution space as a starting point for the least square method and address the problems involving fitness breaking. We apply the proposed approach to XOR problem, 10 bit odd parity problem and many real-world benchmark data sets such as handwriting data set from CEDAR, breast cancer and heart disease data sets from UCI ML repository. The comparative results based on classification accuracy and the time complexity are discussed.
A LOCAL TRAINING-PRUNING APPROACH FOR RECURRENT NEURAL NETWORKS
Authors: LEUNG CHI-SING , LAM PING-MAN
Published: March 2003

The global extended Kalman filtering (EKF) algorithm for recurrent neural networks (RNNs) is plagued by the drawback of high computational cost and storage requirement. In this paper, we present a local EKF training-pruning approach that can solve this problem. In particular, the by-products, obtained along with the local EKF training, can be utilized to measure the importance of the network weights. Comparing with the original global approach, the proposed local approach results in much lower computational cost and storage requirement. Hence, it is more practical in solving real world problems. Simulation showed that our approach is an effective joint-training-pruning method for RNNs under online operation.
CLASSICAL VELOCITY IN κ-DEFORMED POINCARÉ ALGEBRA AND A MAXIMUM ACCELERATION
Authors: RAMA S. KALYANA
Published: March 2003

We study the commutators of the κ-deformed Poincaré algebra (κPA) in an arbitrary basis. It is known that the two recently studied doubly special relativity theories correspond to different choices of κPA bases. We present another such example. We consider the classical limit of κPA and calculate particle velocity in an arbitrary basis. It has standard properties and its expression takes a simple form in terms of the variables in the Snyder basis. We then study the particle trajectory explicitly for the case of a constant force. Assuming that the spacetime continuum, velocity, acceleration, etc. can be defined only at length scales greater than x min ≠ 0, we show that the acceleration has a finite maximum.
ERROR ESTIMATION OF EIGENFREQUENCIES FOR ELASTICITY AND SHELL PROBLEMS
Authors: ODEN J. TINSLEY , PRUDHOMME SERGE , WESTERMANN TIM , BASS JON , BOTKIN MARK E.
Published: March 2003

In this paper, a method for deriving computable estimates of the approximation error in eigenvalues or eigenfrequencies of three-dimensional linear elasticity or shell problems is presented. The analysis for the error estimator follows the general approach of goal-oriented error estimation for which the error is estimated in so-called quantities of interest, here the eigenfrequencies, rather than global norms. A general theory is developed and is then applied to the linear elasticity equations. For the shell analysis, it is assumed that the shell model is not completely known and additional errors are introduced due to modeling approximations. The approach is then based on recovering three-dimensional approximations from the shell eigensolution and employing the error estimator developed for linear elasticity. The performance of the error estimator is demonstrated on several test problems.
A PROOF OF THE INF–SUP CONDITION FOR THE STOKES EQUATIONS ON LIPSCHITZ DOMAINS
Authors: BRAMBLE JAMES H.
Published: March 2003

The purpose of this paper is to present a rather simple proof of an inequality of Nečas9 which is equivalent to the inf–sup condition. This inequality is fundamental in the study of the Stokes equations. The boundary of the domain is only assumed to be Lipschitz.
SOLVING STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS BASED ON THE EXPERIMENTAL DATA
Authors: BABUŠKA IVO , LIU KANG-MAN , TEMPONE RAÚL
Published: March 2003

We consider a stochastic linear elliptic boundary value problem whose stochastic coefficient a(x, ω) is expressed by a finite number NKL of mutually independent random variables, and transform this problem into a deterministic one. We show how to choose a suitable NKL which should be as low as possible for practical reasons, and we give the a priori estimates for modeling error when a(x, ω) is completely known. When a random function a(x, ω) is selected to fit the experimental data, we address the estimation of the error in this selection due to insufficient experimental data. We present a simple model problem, simulate the experiments, and give the numerical results and error estimates.
LINK-CUTTING BUBBLES FOR THE STABILIZATION OF CONVECTION-DIFFUSION-REACTION PROBLEMS
Authors: BREZZI F. , HAUKE G. , MARINI L. D. , SANGALLI G.
Published: March 2003

It is known that the addition and elimination of suitable bubble functions can result in a stabilized scheme of the SUPG-type. Residual-Free Bubbles (RFB), in particular, can assure a quasi-optimal stabilized scheme, but they are difficult to compute in one dimension and nearly impossible to compute in two and three dimensions, unless in special limit cases. Strongly convection-dominated problems (without reaction terms) are one of these cases, where it is possible to find reasonably simple computable bubbles that provide a stabilizing effect as good as that of true RFB. Here, although in a one-dimensional framework, we analyze the case in which a non-negligible reaction term is present, and provide a simple recipe for spotting a suitable bubble space (adding two bubbles to each element) that provides a very good stabilizing effect. The method adapts very well to all regimes with continuous transitions from one regime to another. It is clear that the one-dimensional case, in itself, has no real interest. We believe, however, that the discussion can cast some light on the interaction between convection and reaction that could be useful in future works dealing with multidimensional, more realistic problems.
Is the Association Between Parity and Coronary Heart Disease Due to Biological Effects of Pregnancy or Adverse Lifestyle Risk Factors Associated With Child-Rearing?
Authors: Lawlor Debbie A. , Emberson Jonathan R. , Ebrahim Shah , Whincup Peter H. , Wannamethee S. Goya , Walker Mary , Smith George Davey
Published: March 2003

Background—

Parity is associated with coronary heart disease (CHD) risk. In the present study, we assessed the associations between number of children and CHD in both women and men.

Methods and Results—

A total of 4286 women and 4252 men aged 60 to 79 years from 24 British towns were studied. Number of children was positively associated with body mass index and waist-hip ratio in both sexes. In women but not in men, number of children was inversely associated with high-density lipoprotein cholesterol and was positively associated with triglycerides and diabetes. For both sexes, similar “J” shaped associations between number of children and CHD were observed, with the prevalence lowest among those with 2 children and increasing linearly with each additional child beyond 2. For those with at least 2 children, each additional child increased the age-adjusted odds of CHD by 30% (odds ratio, 1.30; 95% confidence interval, 1.17 to 1.44) for women and by 12% for men (odds ratio, 1.12; 95% confidence interval, 1.02 to 1.22). Adjustment for obesity and metabolic risk factors attenuated the associations between greater number of children and CHD in both sexes, although in women some association remained.

Conclusions—

Lifestyle risk factors associated with child-rearing lead to obesity and result in increased CHD in both sexes; biological responses of pregnancy may have additional adverse effects in women.
Twenty-Year Survival After Coronary Artery Surgery
Authors: Weintraub William S. , Clements Stephen D. , Crisco L. Van-Thomas , Guyton Robert A. , Craver Joseph M. , Jones Ellis L. , Hatcher Charles R.
Published: March 2003

Background—

Coronary artery bypass graft (CABG) surgery has been performed frequently for symptomatic coronary atherosclerotic heart disease for more than 30 years. However, uncertainty exists regarding the relationship between long-term survival after CABG and readily available clinical correlates of mortality.

Methods and Results—

We studied outcome at 20 years by age, sex, and other variables in 3939 patients who had CABG surgery from 1973 to 1979 in the Emory University System of Healthcare. Twenty-year survival, freedom from myocardial infarction, and freedom from repeat CABG were 35.6% (95% confidence interval [CI], 33.9% to 37.3%), 66.6% (95% CI, 64.6% to 68.6%), and 59.1% (95% CI, 56.9% to 61.5%). Multivariate correlates of late mortality were age (hazard ratio [HR], 1.46 per 10 years), female sex (HR, 1.21), hypertension (HR, 1.44), angina class (HR, 1.07 per class increase of 1), prior CABG (HR, 1.72), ejection fraction (HR, 1.07 per 10-point decrease), number of vessels diseased (HR, 1.11 per 1-vessel increase), and weight (HR, 1.04 per 10 kg). Twenty-year survival by age was 55%, 38%, 22%, and 11% for age <50, 50 to 59, 60 to 69, and >70 years at the time of initial surgery. Survival at 20 years after surgery with and without hypertension was 27% and 41%, respectively. Similarly, 20-year survival was 37% and 29% for men and women.

Conclusions—

Symptomatic coronary atherosclerotic heart disease requiring surgical revascularization is progressive with continuing events and mortality. Clinical correlates of mortality significantly impact survival over time and may help identify long-term benefits after CABG.
Prevention of Heart Failure in Patients in the Heart Outcomes Prevention Evaluation (HOPE) Study
Authors: Arnold J. Malcolm O. , Yusuf Salim , Young James , Mathew James , Johnstone David , Avezum Alvaro , Lonn Eva , Pogue Janice , Bosch Jackie
Published: March 2003

Background—

Previous trials in the prevention of heart failure have been restricted to patients with low ejection fraction or hypertension. We assessed an angiotensin-converting enzyme (ACE) inhibitor, ramipril, to prevent the development of heart failure in high-risk patients without known low ejection fraction or heart failure.

Methods and Results—

We randomly assigned 9297 patients to receive double-blind ramipril (10 mg daily) or matching placebo for 4.5 years. Death attributable to heart failure, hospitalization for heart failure, initiation of open-label ACE inhibitor for heart failure, or development of typical signs or symptoms of heart failure developed in 951 patients and was associated with a 4.01-fold increase in the risk of death (
P
<0.0001). The rate of developing heart failure was significantly increased with coronary disease (risk ratio, 2.17), microalbuminuria (1.82), left ventricular hypertrophy (1.47), increasing age (by decade, 1.37), and diabetes (1.36). Ramipril reduced new-onset heart failure rate from 11.5% to 9.0% (relative risk, 0.77; 95% CI, 0.68 to 0.87;
P
<0.0001). Ramipril consistently reduced heart failure rate both in those with (relative risk, 0.87) and those without an interim myocardial infarction (relative risk, 0.78). Ramipril also reduced the heart failure rate more in patients with baseline systolic pressure above the median (139 mm Hg) (relative risk, 0.67) compared with those below the median (relative risk, 0.91;
P
=0.024 for interaction of group by treatment).

Conclusion—

Ramipril significantly reduces the rate of development of heart failure in patients at high risk of cardiovascular events.
Enalapril Reduces the Incidence of Diabetes in Patients With Chronic Heart Failure
Authors: Vermes Emmanuelle , Ducharme Anique , Bourassa Martial G. , Lessard Myriam , White Michel , Tardif Jean-Claude
Published: March 2003

Background—

Diabetes mellitus is a predictor of morbidity and mortality in patients with heart failure. The effect of angiotensin-converting enzyme (ACE) inhibitors on the prevention of diabetes in patients with left ventricular dysfunction is unknown. The aim of this retrospective study was to assess the effect of the ACE inhibitor enalapril on the incidence of diabetes in the group of patients from the Montreal Heart Institute enrolled in the Studies of Left Ventricular Dysfunction (SOLVD).

Methods and Results—

Clinical charts were evaluated for fasting plasma glucose (FPG) levels by blinded reviewers. A diagnosis of diabetes was made when a FPG ≥126 mg/dL (7 mmol/L) was found at 2 visits (follow-up, 2.9±1.0 years). Of the 391 patients enrolled at the Montreal Heart Institute, 291 were not diabetic (FPG <126 mg/dL without a history of diabetes), 153 of these were on enalapril and 138 were on placebo. Baseline characteristics were similar in the 2 groups. Forty patients developed diabetes during follow-up, 9 (5.9%) in the enalapril group and 31 (22.4%) in the placebo group (
P
<0.0001). By multivariate analysis, enalapril remained the most powerful predictor for risk reduction of developing diabetes (hazard ratio, 0.22; 95% confidence intervals, 0.10 to 0.46;
P
<0.0001). The effect of enalapril was striking in the subgroup of patients with impaired FPG (110 mg/dL [6.1 mmol/L] ≤FPG <126 mg/dL) at baseline: 1 patient (3.3%) in the enalapril group versus 12 (48.0%) in the placebo group developed diabetes (
P
<0.0001).

Conclusions—

Enalapril significantly reduces the incidence of diabetes in patients with left ventricular dysfunction, especially those with impaired FPG.
Cardiovascular Morbidity and Mortality in Women Diagnosed With Rheumatoid Arthritis
Authors: Solomon Daniel H. , Karlson Elizabeth W. , Rimm Eric B. , Cannuscio Carolyn C. , Mandl Lisa A. , Manson JoAnn E. , Stampfer Meir J. , Curhan Gary C.
Published: March 2003

Background—

Rheumatoid arthritis may be associated with an increased risk of cardiovascular disease. We compared the incidence rates of myocardial infarction and stroke in subjects with and without rheumatoid arthritis.

Methods and Results—

A prospective cohort study was conducted among the 114 342 women participating in the Nurses’ Health Study who were free of cardiovascular disease and rheumatoid arthritis at baseline in 1976. All self-reported cases of rheumatoid arthritis were confirmed by medical record review. Fatal and nonfatal myocardial infarctions and strokes were similarly confirmed. Multivariate pooled logistic regression was used to adjust for potential cardiovascular risk factors. Five hundred twenty-seven incident cases of rheumatoid arthritis and 3622 myocardial infarctions and strokes were confirmed during 2.4 million person-years of follow-up. The adjusted relative risk of myocardial infarction in women with rheumatoid arthritis compared with those without was 2.0 (95% confidence interval [CI], 1.23 to 3.29). For stroke, the adjusted relative risk was 1.48 (95% CI, 0.70 to 3.12). Women who had rheumatoid arthritis for at least 10 years had a risk for myocardial infarction of 3.10 (95% CI, 1.64 to 5.87).

Conclusion—

In this large prospective cohort of women, participants with rheumatoid arthritis had a significantly increased risk of myocardial infarction but not stroke compared with those without rheumatoid arthritis. If these data are confirmed, aggressive coronary heart disease prevention strategies should be tested for persons with rheumatoid arthritis.
Antibiotic Therapy After Acute Myocardial Infarction
Authors: Zahn Ralf , Schneider Steffen , Frilling Birgit , Seidl Karlheinz , Tebbe Ulrich , Weber Michael , Gottwik Martin , Altmann Ernst , Seidel Friedrich , Rox Jürgen , Höffler Ulrich , Neuhaus Karl-Ludwig , Senges Jochen
Published: March 2003

Background—

Infection with
Chlamydia pneumoniae
is suspected to contribute to the pathogenesis of human atherosclerosis. We investigated whether treatment with the macrolide antibiotic roxithromycin would reduce mortality or morbidity in patients with an acute myocardial infarction.

Methods and Results—

Eight hundred seventy-two patients with an acute myocardial infarction (AMI) were randomly assigned to receive double-blind treatment with either 300 mg roxithromycin or placebo daily for 6 weeks. Primary end point was total mortality during 12-month follow-up. Four hundred thirty-three patients were treated with roxithromycin and 439 with placebo. With the exception of a higher proportion of patients suffering an anterior wall AMI (48.1% in the roxithromycin group versus 40.2% in the placebo group;
P
=0.027) and a lower prevalence of chronic obstructive pulmonary disease in the roxithromycin group (3.5% versus 6.9%,
P
=0.028), baseline characteristics, reperfusion therapy, and medical treatment were well balanced between the two groups. More patients in the roxithromycin group interrupted their study medication before completion of at least 4 weeks of treatment (78 of 433 [18%] versus 48 of 439 [11%];
P
=0.003; odds ratio, 1.8; 95% CI, 1.2 to 2.6). Follow-up at 12 months was achieved in 868 of 872 (99.5%) patients. Total mortality at 12 months was 6.5% (28 of 431) in the roxithromycin group compared with 6.0% (26 of 437) in the placebo group (odds ratio, 1.1; 95% CI, 0.6 to 1.9;
P
=0.739). There were also no differences in the secondary combined end points at 12 months.

Conclusions—

Treatment of AMI patients with roxithromycin did not reduce event rates during 12 months of follow-up. Therefore, our findings do not support the routine use of antibiotic treatment with a macrolide in patients with AMI.
Isolated Ambulatory Hypertension Predicts Cardiovascular Morbidity in Elderly Men
Authors: Björklund Kristina , Lind Lars , Zethelius Björn , Andrén Bertil , Lithell Hans
Published: March 2003

Background—

Little is known about isolated ambulatory hypertension, a state with elevated ambulatory but normal office blood pressure (BP). This study aimed to investigate the prognostic significance of isolated ambulatory hypertension for cardiovascular morbidity in a population of elderly men.

Methods and Results—

At baseline, 24-hour ambulatory BP and metabolic and cardiac risk profiles were evaluated in 578 untreated 70-year-old men, participants of a population-based cohort. Subjects with isolated ambulatory hypertension (office BP <140/90 and daytime BP ≥135/85) and sustained hypertension (office BP ≥140/90 and daytime BP ≥135/85) had increased plasma glucose, body mass index, and echocardiographically determined left ventricular relative wall thickness compared with normotensive subjects (office BP <140/90 and daytime BP <135/85). Seventy-two cardiovascular morbid events (2.37 per 100 person-years at risk) occurred over 8.4 years of follow-up. The prognostic value of isolated ambulatory and sustained hypertension was assessed with Cox proportional hazard regression. Multivariate models adjusting for serum cholesterol, smoking, and diabetes demonstrated that both isolated ambulatory hypertension (hazard ratio [HR], 2.77; 95% CI, 1.15 to 6.68) and sustained hypertension (HR, 2.94; 95% CI, 1.49 to 5.82) were independent predictors of cardiovascular morbidity. In a multivariate model with continuous BP variables, ambulatory daytime systolic BP (HR for 1 SD increase, 1.47; 95% CI, 1.09 to 1.97) was associated with an adverse outcome independently of office systolic BP.

Conclusions—

In the present study, isolated ambulatory hypertension as well as sustained hypertension predicted cardiovascular morbidity. The findings suggest that 24-hour ambulatory BP monitoring may disclose important prognostic information also in subjects characterized as normotensive according to office BP.
Bone Marrow–Derived Cardiomyocytes Are Present in Adult Human Heart
Authors: Deb Arjun , Wang Shaohua , Skelding Kimberly A. , Miller Dylan , Simper David , Caplice Noel M.
Published: March 2003

Background—

Recent studies have identified cardiomyocytes of extracardiac origin in transplanted human hearts, but the exact origin of these myocyte progenitors is currently unknown.

Methods and Results—

Hearts of female subjects (n=4) who had undergone sex-mismatched bone marrow transplantation (BMT) were recovered at autopsy and analyzed for the presence of Y chromosome–positive cardiomyocytes. Four female gender-matched BMT subjects served as controls. Fluorescence in situ hybridization (FISH) for the Y chromosome was performed on paraffin-embedded sections to identify cells of bone marrow origin with concomitant immunofluorescent labeling for α-sarcomeric actin to identify cardiomyocytes. A total of 160 000 cardiomyocyte nuclei were analyzed approximating 20 000 nuclei per patient. The mean percentage of Y chromosome–positive cardiomyocytes in patients with sex-mismatched BMT was 0.23±0.06%. Not a single Y chromosome–positive cardiomyocyte was identified in any of the control patients. Immunofluorescent costaining for laminin and chromosomal ploidy analysis with FISH showed no evidence of either pseudonuclei or cell fusion in any of the chimeric cardiac myocytes identified.

Conclusions—

These data establish for the first time human bone marrow as a source of extracardiac progenitor cells capable of de novo cardiomyocyte formation.
Randomized Study Comparing Radiofrequency Ablation With Cryoablation for the Treatment of Atrial Flutter With Emphasis on Pain Perception
Authors: Timmermans Carl , Ayers Gregory M. , Crijns Harry J.G.M. , Rodriguez Luz-Maria
Published: March 2003

Background—

Radiofrequency ablation (RF) of atrial flutter (AFL) has a high procedural efficacy, a low recurrence rate, and reports of procedure-related pain. The aim of the present study was to compare RF with cryoablation (cryo) for the treatment of AFL, with emphasis on pain perception during application of energy.

Methods and Results—

Fourteen patients (55±11 years, 11 males) with AFL were randomized to receive ablation of the cavotricuspid isthmus (CTI) by either RF or cryo. Cryothermia was delivered with the CryoCor Cryoablation System (10F, 6-mm tip), and radiofrequency energy was delivered with the use of an 8-mm–tip catheter. Pain was evaluated according to a visual analogue scale (VAS; 0 to 100). All patients in the cryo group were successfully ablated with a mean of 18 applications (9 sites), and RF was successful in 6 of 7 patients (not significant) with 13 applications (not significant). The mean temperature was −82°C and 55°C for cryo and RF, respectively. One patient in the cryo group perceived pain, versus all 7 patients in the RF group (
P
<0.05). The proportion of painful applications averaged 75.3% in the RF group and 2.0% in the cryo group (
P
<0.05), whereas the corresponding VAS for pain was 38.3±25.3 and 0.32±0.86, respectively (
P
<0.05). At 6-month follow-up, there were no recurrences of atrial flutter.

Conclusion—

Cryo, as compared with RF, produces significantly less pain during application. Although in the present study there was no significant difference in efficacy, larger studies will be needed to definitively compare efficacy.