bluuebunny/crossref_metadata_2025 huggingface dataset:
A System of Demand Equations Satisfying Effectively Global Curvature Conditions*
Authors: COOPER RUSSEL J. , McLAREN KEITH R. , PARAMESWARAN PRIYA
Published: October 2007

The MP1GLOG specification of an indirect utility function allows a parametric representation in terms of expenditure and two unit cost functions. An appropriate specification of these unit cost functions resolves the conflict between the need for flexibility and satisfaction of curvature restrictions by allowing the use of a flexible unit cost function which satisfies curvature conditions for all positive prices. The resulting demand system will then satisfy curvature restrictions over a wide range of prices and expenditures, and hence allow policy conclusions consistent with the restrictions of economic theory.
The Experience‐Earnings Profile in Australia*
Authors: BORLAND JEFF , SUEN ANTHONY
Published: October 2007

This paper investigates the goodness‐of‐fit' and effect on estimates of the experience‐earnings profile of alternative specifications of the human capital earnings function for a sample of full‐time male workers in Australia. It is concluded that it is difficult to differentiate between specifications of the earnings function which include a cubic experience term, cubic plus quartic experience terms, or a linear spline function in experience–each of these specifications appears to marginally dominate the quadratic specification and a non‐parametric approach. A modified Gompertz function is found to perform poorly.
Australia's Real Exchange Rate–Is it Explained by the Terms of Trade or by Real Interest Differentials?*
Authors: GRUEN DAVID W. R. , WILKINSON JENNY
Published: October 2007

We find weak evidence of a stable relationship between the Australian real exchange rate and the terms of trade from 1969 to 1990. Since the float, the terms of trade and long real interest differentials together help to explain the real exchange rate. Our best estimates are that a real exchange rate appreciation of about 0.3 to 0.5 per cent is associated with a 1 per cent improvement in the terms of trade, while an appreciation of about 2 to 3½ per cent is associated with an increase of 1 percentage point in the differential between Australian and world long real interest rates.
Is Housing Activity a Leading Indicator?*
Authors: PENM JAMMIE H. , TERRELL R.D.
Published: October 2007

We investigate whether housing activity is a leading indicator of general activity using two dynamic systems. In the national account system, the results indicate that dwelling investment contains leading information for gross national expenditure. In a five‐variable system including a measure of economic activity, housing activity, money, prices and a short‐term interest rate, housing activity is found to provide an important linkage between economic activity and the rest of the system. These results consistently affirm that housing activity is a leading indicator of general economic activity.
Regulation and Deregulation of the Supply of Bulk Liquid Petroleum Gas in Queensland: A Case Study*
Authors: ANDERSON DON , FINN FRANK
Published: October 2007

This paper presents a case study of the regulation and subsequent deregulation of the bulk liquid petroleum gas industry in Queensland. During the period of the regulated franchise system, prices paid by bulk LPG customers in south‐east Queensland were higher than those paid by customers in northern NSW (where no similar regulations existed) despite both sets of customers being supplied from the same source. In response to higher prices, some customers attempted to circumvent the regulations by utilizing inefficient configurations of gas cylinders as a substitute for bulk supply. Following deregulation, bulk LPG prices fell in previously franchised areas of south‐east Queensland.
The Rise and Fall and Fall of Keynesian Economics?*
Authors: LEESON ROBERT
Published: October 2007

This paper examines the argument that Professor Blinder presented to the Bicentennial Australian Conference of Economists, that the Phillips curve is ‘alive and well’. It is argued below that Blinder's conclusion is, at best, unproven. It also highlights The Keynesian Recovery, outlined by Howitt and others, which has not resurrected the trade‐off interpretation of Phillips's work.
Word‐of‐Mouth Communication and Price as a Signal of Quality*
Authors: KENNEDY PETER W.
Published: October 2007

This paper demonstrates that word‐of‐mouth communication between consumers provides a mechanism to support signalling. Particularly, a separating equilibrium can be supported where a low introductory price signals high quality. The equilibrium price path is qualitatively similar to that supported by repeat buying. Separation is less likely than in repeat buying because word‐of‐mouth communication between consumers is likely to be less effective in transmitting information than repeat buying. The equivalence of word‐of‐mouth communication and repeat buying breaks down entirely when communication is costly because consumers then have a strict incentive not to communicate if separation occurs. This undermines the mechanism that supports the separation.
Personal Income Tax Deductions in Australia, 79/1978–1990/91*
Authors: BALDRY JONATHAN
Published: October 2007

An analysis of deductions claimed against personal income tax in Australia over the period 1978/79–1990/91 indicates that the level of claims is positively related to both the marginal tax rate facing the taxpayer and to the taxpayer's net income. However, only a small part of the large increase in deductions claimed can be explained by these factors. An exogenous trend indicates an increased ‘taste’ for deductions. Evidence for this is a high correlation between deductions claimed and the proportion of taxpayers who submit their returns via a tax agent
Predicting the Quality of an Unborn Grange*
Authors: BYRON R.P. , ASHENFELTER O.
Published: October 2007

In a recent paper Ashenfelter, Ashmore and Lalonde found they could explain the variation in the price (and quality) of Bordeaux vintages by a combination of age, temperature and rainfall. The same ideas are applied here to Grange Hermitage, Australia's premier wine. Weather variation is less important than in Bordeaux. However, some remarkably robust results are obtained: a ‘quality index’ for Grange is derived, predictions about still unreleased vintages are made, the Australian regression coefficients work well in the Bordeaux equation, and issues relating to market efficiency in the pricing of young wines are examined
The Intergenerational Incidence of Government Spending*
Authors: TAN KIM‐HENG
Published: October 2007

This paper analyzes the effect of an increase in government spending on the welfare of different generations in a dynamic general equilibrium model. The paper shows that the intergenerational incidence of government spending on a public good is determined not only by the welfare effects due to the public good and to financing the good but also by a welfare effect due to intertemporal substitution between private consumption when government spending is increased. The degree of substitutability between private consumption and public spending is shown to be a key determinant of this incidence.
Relative Incentives and Trade Strategies: Typologies and Possibilities*
Authors: MILNER CHRIS
Published: October 2007

The paper investigates trade strategy classification within a general equilibrium framework which includes both tradeables and non‐tradeables. In a three‐sector model there is apparently a wider range of trade strategies available than in the traditional two‐sector model. Besides pure import‐substitution (IS) and export promotion (EP) policies, mixed IS/EP policies might seek (ex ante) to create a protradeables bias rather than approximate neutrality. However, the ex‐post outcome depends upon the substitution, complementarity and/or income effects of commercial policies on equilibrium relative prices. The paper demonstrates that the actual change in the incentive structure may differ from the intended strategy.
The Question of Access to the Japanese Market*
Authors: DRYSDALE PETER
Published: October 2007

It is now widely accepted that Japan has relatively low official barriers to merchandise, particularly manufactured goods, trade relative to other industrial countries. Yet, Japan's current account and trade surpluses have encouraged the view that there must be special ‘hidden barriers’ to accessing the Japanese market, and a literature has developed on the premise that Japanese business organizations (keiretsu) limit foreign penetration of markets of manufactured goods. This paper surveys the main elements of this literature and questions some of the assumptions upon which recent American policy in this area seems to have been developed.
Optimal Hedging Under Forward‐Looking Behaviour*
Authors: LENCE SERGIO H. , HAYES DERMOT J.
Published: October 2007

The study focuses on the production and hedging behaviour of forward‐looking risk‐averse competitive firms. It is shown that there is separation between production and hedging. Optimal productin for a forward‐looking firm is identical to that of an otherwise equivalent myopic firm. However, the optimal forward‐looking hedge differs from the optimal myopic hedge. If forward prices are unbiased, full hedging is suboptimal when the firm is forward looking and output and material input prices are contemporaneously related. Furthermore, under certain conditions, the optimal forward‐looking hedge under unbiased forward prices is strictly smaller than the full hedge.
Portfolio Implications of an Equity Rain in Australia*
Authors: LIM G. C. , KELLS STUART S.
Published: October 2007

In the next decade Australia will experience a substantial privatization program. This represents a switch away from public debt financing towards public equity financing. In this paper, estimates of the likely effect of the government's privatization program on corporate financing are provided. The main result of an increase in the supply of equities along with a commensurate reduction in the supply of government debt is to cause a significant increase in the relative cost of equity, thereby creating incentives for corporate financiers to emphasize reliance on debt financing relative to equity financing. The estimated effect on the weighted cost of finance in the economy, while positive, is small
The Distribution of Work in Australia*
Authors: DAWKINS PETER
Published: October 2007

Since the 1960s substantial increases in unemployment, female participation and employment, part‐time employment, and persons working long hours, have produced a wider distribution of work between individuals in the Australian labour market. A widening distribution of work between income units and households has also occurred. The effect on the distribution of earnings and ‘well‐being’ is considered. The case for work‐sharing policies to reduce unemployment and create a more even distribution of work is rejected. Labour market deregulation combined with a negative income tax system may be a way of increasing employment without creating a substantial ‘working poor’.
Nonlinearities in Exchange‐Rate Dynamics: Evidence from Five Currencies, 1973–94
Authors: BLEANEY MICHAEL , MIZEN PAUL
Published: October 2007

Although exchange rates appear to follow a random walk when tested against linear alternatives, the null hypothesis of a random walk is rejected against a cubic alternative which embodies the intuition that the rate of mean‐reversion increases with distance from equilibrium. A possible theoretical foundation for such a model is suggested. The model is tested on bilateral real exchange rates between four major currencies, and on the real effective exchange rate of these four plus the Australian dollar. The cubic model consistently outperforms its linear counterpart and the results imply that real exchange rates are in fact stationary.
Targeting Welfare: A Comment*
Authors: WHITEFORD PETER
Published: October 2007

Mitchell, Harding and Gruen (1994) survey the redistributive impact of Australia's targeted social security system using Luxembourg Income Study data. They argue that the Australian system has the highest target efficiency among ten countries, but the lowest benefit generosity (after taking account of tax clawbacks), implying that generosity is greater in universal or contributory systems. This comment identifies methodological problems with the accounting framework used by Mitchell, Harding and Gruen, although also arguing that the Australian targeted income support system is likely to be more efficient at reducing poverty than social insurance systems. An alternative methodological approach is outlined.
Imputation of Female Labour Market Experience: Some Australian Evidence on the Zabalza and Arrufat Method*
Authors: KIDD MICHAEL P. , SHANNON MICHAEL
Published: October 2007

Recent empirical studies of gender discrimination point to the importance of accurately controlling for accumulated labour market experience. Unfortunately in Australia, most data sets do not include information on actual experience. The current paper using data from the National Social Science Survey 1984, examines the efficacy of imputing female labour market experience via the Zabalza and Arrufat (1985) method. The results suggest that the method provides a more accurate measure of experience than that provided by the traditional Mincer proxy. However, the imputation method is sensitive to the choice of identification restrictions. We suggest a novel alternative to a choice between arbitrary restrictions.
Technological Catch‐Up and Economic Growth in East Asia and the Pacific*
Authors: DRYSDALE PETER , HUANG YIPING
Published: October 2007

This paper examines factors contributing to the faster economic growth in East Asia relative to other APEC economies. A simple but popular model is applied using purchasing power parity income estimates. Contrary to the view recently advanced by Krugman, we find that productivity improvement was an important factor contributing to the rapid East Asian growth. For many East Asian economies such as Japan, Korea, Taiwan and Hong Kong, a large proportion of higher than average growth is attributable to technological progress.
The Market for Surrogate Motherhood Contracts*
Authors: HEWITSON GILLIAN
Published: October 2007

Surrogate motherhood is a controversial subject, and has not previously been formally modelled by economists. In this paper, a neoclassical model of the market for surrogate motherhood contracts is developed, based on the utility maximizing decisions of potential surrogate mothers and commissioning parties. The presence of both altruistic and self‐interested behaviour generates unusual market outcomes.
Do Leading Indicators Really Predict Australian Business Cycle Turning Points?
Authors: LAYTON ALLAN P.
Published: October 2007

In earlier work, Layton (1994) demonstrated how Hamilton's (1991) quasi‐bayesian, markov (constant transition probability parameters), regime‐switching model could be used to characterize the nature of the Australian business cvcle. However, Diebold, Lee and Weinbach (1992), Durland and McCurdy (1994), and Filardo(1994) have suggested approaches which allow the markov transition probabilities to he non‐constant. In this paper the Australian coincident index is employed as a summative measure of the business cycle and the transition probability parameters are allowed to vary. In particular, leading and long leading indexes are used as putative determinants of these transition probabilities to test whether, in this framework, these indexes systematically influence the probability of phase changes in the business cycle.
National Competition Policy*
Authors: KING STEPHEN P.
Published: October 2007

National competition policy is having a major effect on Australian industry. The Hilmer committee recommendations on infrastructure access, competitive neutrality, restructuring of public enterprises and legislative review have been accepted by all Australian governments. The underlying economic principles, however, are not necessarily reflected in the reforms. The process of negotiated infrastructure access established under national competition policy may lead to monopoly rather than competitive pricing. Structural reforms of government business enterprises have ignored the benefits of integration and the relevant market characteristics. Legislative review has resulted in considerable political controversy. In some cases, competition policy can be improved by simple amendments to legislation while in other cases a clearer understanding of the relevant trade‐offs may improve the reform process.
The Economic Performance of the States and Territories of Australia: 1861–1992
Authors: NERI FRANK
Published: October 2007

This paper examines the economic performance of the States and Territories of Australia from 1861 to 1992. Original estimates of real per capita output for each State are constructed and used to determine whether, for selected periods, the material standards of living of the States converged. Whilst the data suggest that this was the case for the selected subperiods up to the mid 1970s, it appears that from this period the per capita income gap between the richest and poorest States probably widened. The most important factor driving this phenomenon is the ability of States to successfully adapt to national and international sectoral changes.
The Efficiency Effects of Removing the Diesel Fuel Rebate Scheme
Authors: ALBON ROBERT
Published: October 2007

The diesel fuel rebate scheme which returns most of the excise on diesel fuel used off‐road by agricultural and mineral producers has been debated. Removal could cause three inefficiencies (input choice distortion. deadweight losses on reduced exports, and flowon inefficiencies in domestic processing) and two efficiencies (from reducing other taxes and savings on administrative and compliance costs). Empirical studies suggest high net efficiency costs from removal, but while business input taxes have no place in an efficient taxation structure, a small reduction in the rebate could yield some revenue at a low marginal deadweight loss.
The Behaviour of Declining Industries
Authors: KING STEPHEN P.
Published: October 2007

This paper examines how the prospect of imminent exit by a competitor in a declining industry affects the market behaviour of that industry prior to exit. We show that ‘survivor’ firms have an incentive to increase their holdings of inventories and to hold excess capacity before exit occurs. Preparation for the failure of a rival will also involve increasing output. This will push down the market price and may hasten the rival firm's demise. The welfare consequences of these actions are mixed but can be very different from the same actins in a growing or stable industry. In particular, holding excess capacity or increased inventories may be procompetitive.
Intertemporal Solvency in the Small Open Economy of Australia
Authors: LEACHMAN LORI L. , THORPE MICHAEL
Published: October 2007

This paper employs cointegration and multicointegration analysis to explore the issue of external solvency in the small open economy of Australia. Results indicate that in the fixed exchangerate era exports and imports are multicointegrated while in the more recent floating exchange‐rate period the series do not share a conventional long‐run equilibrium relationship. The results are consistent with intertemporal external solvency in the early period and insolvency more recently. Sustainability criteria are reviewed. Indications are that low saving and investment rates may inhibit Australia's abiliry to sustain persistent external imbalances, however, recent fiscal adjustments may work to abate this problem.
Are Australia's Current Account Deficits Excessive?
Authors: CASHIN PAUL , McDERMOTT C. JOHN
Published: October 2007

This paper compares the evolution of the Australian current account balance over the period 1954‐94 against an optimal current account derived from a consumption‐smoothing model. The findings indicate that the Australian current account was not used to smooth consumption optimally in the period prior to the relaxation of capital controls in the early 1980s. The results also suggest that in the period since the mid‐1980s Australia's current account deficits have become excessive, and that the increase in net national saving required to satisfy its external borrowing constraint is about 2 to 4 per cent of GDP.
Industrial Structure and Australia– UK Intra‐Industry Trade
Authors: MENON JAYANT , GREENAWAY DAVID , MILNER CHRIS
Published: October 2007

This paper tests industry‐specific hypotheses of the determinants of intra‐industry trade in the context of Australia‐UK trade. In doing so it separates intra‐industry trade (ITT) into ITT in horizontally differentiated products and ITT in vertically differentiated products. It finds that the latter is the dominant former of ITT. Further the paper investigates the robustness of empirical results on testing industry‐specific hypotheses to the choice of national (UK or Australian) industrial structure characteristics. The assumption of uniform industrial structures across countries adopted in other studies is shown not to be justified.
Fiscal Illusion at the Local Level: An Empirical Test Using Australian Municipal Data
Authors: DOLLERY BRIAN , WORTHINGTON ANDREW
Published: October 2007

This paper seeks to extend the literature on the empirical analysis of fiscal illusion in two ways. First, it provides a simultaneous test of four specific hypotheses subsumed under fiscal illusion, namely the revenue‐complexity, renter illusion, debt illusion and flypaper models. and second, it adds evidence drawn from the Australian institutional milieu to existing empirical work which has an overwhelming North American focus. Using 1991 data from 46 local government authorities in Tasmania, the results suggest significant support for revenue‐complexity, debt illusion, and the degree of indirectness of the revenue system.
What Determines Research Output of Academic Economists?
Authors: FOX KEVIN J. , MILBOURNE ROSS
Published: October 2007

This paper looks at the characteristics that explain research productivity in a cross section of academic economists. From a sample of 150 economists, we obtained data on a range of human capital variables, teaching loads and research funding. The results suggest that human capital variables, particularly the grade of honours and the nature and location of the PhD., are especially important in explaining a quality‐weighted research output measure. Teaching loads are also significant. In particular, we find that a 10 per cent increase in the number of teaching hours may reduce research output by as much as 20 per cent, whereas a 10 per cent increase in the number of grants held per year may raise output per year by as much as 15 per cent.
Ten Years of the PHD Conference in Economics and Business
Authors: QIANG YE , CLEMENTS KENNETH W.
Published: October 2007

Since its commencement in 1987, the PhD Conference in Economics and Business has become an important annual event in Australian Economics. This paper presents an overview of the last ten years of the conference regarding the students involved, their topics and backgrounds, as well as some information on the nature of PhD studies. The experience of these students reveals some key factors that seem to lead to successful research outcomes.
Labour Market Programs and the Australian Beveridge Curve: 1978 to 1997
Authors: WEBSTER ELIZABETH
Published: October 2007

Labour market programs are often advocated on the basis that by re‐introducing unemployed people to the culture of the workplace, they will re‐skill and motivate them enough to make them suitable employees to prospective employers. Accordingly, total employment should rise and vacancy rates fall. If programs work in this manner, we should be able to detect a systematic relationship between labour market program expenditure and the distance of the Beveridge curve from the origin ceteris paribus. There are few studies in the world that have directly tried to assess the impact of labour market program expenditure on the Beveridge curve. Our estimates for Australia over the last 19 years give limited support to the view that most labour market programs nave moved the Beveridge curve inwards.
The Determinants of Foreign Direct Investment in Australia
Authors: YANG JEANNIE YIH YUN , GROENEWOLD NICOLAAS , TCHA MOONJOONG
Published: October 2007

Australia is a recipient of large foreign direct investment (FDI) flows by world standards. Despite this, there is little empirical work on the determinants of FDI in Australia. We carry out an econometric analysis of the determinants of aggregate FDI inflows into Australia since the mid‐1980s. We find that interest rates, wage changes, a measure of the openness of the economy and a variable representing industrial disputes are important determinants of FDI inflow into Australia over the period. The estimated model successfully explains within‐sample variability but this success is greater in the beginning of the sample than at the end.
Australia's Unemployment Problem
Authors: LE ANH T. , MILLER PAUL W.
Published: October 2007

A number of Australian studies have provided microeconomic and macroeconomic perspectives on the causes of, and solutions to, Australia's unemployment problem. This paper provides an evaluation of these studies. Several important findings can be noted. First, from the cross‐sectional studies economists have gained a good understanding of the factors contributing to a high probability of unemployment. Effective use is currently being made of this information. Second, there is general consensus from the time‐series studies regarding the estimates of the aggregate labour demand wage and output elasticities. In addition, it has been widely acknowledged that lower real wages and economic growth would help reduce the high rate of unemployment. Despite the information available we are making slow progress towards reducing the unemployment rate. This may be due to political reasons or because we are unsure of how to deliver the wage cuts and faster rates of economic growth presented as solutions to the unemployment problem.
The Efficiency of State Taxes on Mobile Labour Income
Authors: PETCHEY JEFFREY , SHAPIRO PERRY
Published: October 2007

We model a federation where States levy a tax on the wage income of mobile citizens who shop between States for their preferred tax and public policy package. It is shown that competition between States results in efficient State spending but that the taxes on wage income are inefficient in the sense that mobile taxpayers are allocated inefficiently across States. The implication is that if States tax the wage income of mobile workers, there may be benefits from policy competition (a more competitive federal system) but also costs associated with the inefficiency. The central government can correct for the inefficiency, but this requires a complex system of inter‐State transfers that are difficult to implement in practice.
Men, Women and the Hiring Function
Authors: MUMFORD KAREN , SMITH PETER N.
Published: October 2007

This paper examines the idea of ranking of groups and genders of unemployed labour force participants in terms of their hiring probabilities.We find a clear ranking of men over women in the hiring process in Australia. We also find that amongst males, employed job seekers are ranked above those unemployed and, in turn, above those not in the labour force. For women, the unemployed and employed are not found to be competing with each other, whilst those not in the labour force are ranked below the unemployed.
The Social Construction of Romantic Relationships in Adolescence: Examining the Role of Peer Networks, Gender, and Race*
Authors: Cavanagh Shannon E.
Published: October 2007

Romantic activity is a social psychological phenomenon. Gender, race, and peer networks are key contexts for understanding the social construction of this behavior as gender‐ and race‐based norms structure feelings and behaviors that define “appropriate” romantic activity and peer networks serve as incubators of this activity. With a nationally representative sample of adolescents (N= 8510) drawn from the National Longitudinal Study of Adolescent Health, this study explored the linkages among peer networks, conceptions of idealized romantic relationships and actual romantic relationships, and the ways in which gender and race moderate these associations. Several characteristics of peer networks predicted adolescent attitudes about romantic behaviors as well as actual romantic behavior. Moreover, the linkages among peer networks, romantic attitudes, and romantic behaviors varied by race.
The Role of Quinapril in the Presence of a Weight Loss Regimen: Endothelial Function and Markers of Obesity in Patients With the Metabolic Syndrome
Authors: Nagamia Sameer , Pandian Anbu , Cheema Faiz , Natarajan Rama , Khan Qamar A. , Patel Amar D. , Merchant Nadya , Sola Srikanth , Khan Bobby V.
Published: October 2007

Forty‐four patients with the metabolic syndrome were placed on a reduced‐calorie and reduced‐fat regimen to lose weight throughout a 56‐week period. The patients were treated in a crossover fashion with placebo and the angiotensin‐converting enzyme inhibitor quinapril for 24 weeks each. The study measured endothelial‐dependent flow‐mediated dilation plus serum obesity markers of adiponectin and leptin. Metabolic parameters improved after 56 weeks. Serum adiponectin level increased by 18% (P<.05 vs baseline) and serum leptin level decreased by 16% with placebo (P<.05 vs baseline). These findings were potentiated further in the quinapril group. In comparison with baseline, flow‐mediated dilation was increased by 13% in the placebo group (P=.055 vs baseline) and by 43% in the quinapril group (P<.001 vs baseline and placebo). These findings suggest that weight loss therapy improves endothelial function and markers of obesity. These results are potentiated with quinapril and are independent of changes in metabolic parameters.
Casual Chocolate Consumption and Inhibition of Platelet Function
Authors: Bordeaux Bryan , Yanek Lisa R. , Moy Taryn F. , White Linda W. , Becker Lewis C. , Faraday Nauder , Becker Diane M.
Published: October 2007

Observational studies have associated reduced cardiovascular mortality with chocolate consumption. Feeding studies of high‐dose, flavanol‐rich chocolate show antiplatelet effects, but the effect of casual chocolate consumption on platelet function is unknown. Healthy adults (N=1535) were proscribed from consuming foods affecting platelet function, including chocolate, for 48 hours and completed a 24‐hour dietary recall before ex vivo platelet testing with the Platelet Function Analyzer (PFA)‐100 (Dade Behring, Inc, Deerfield, IL) test and in vivo testing with urinary 11‐dehydro thromboxane B2 (Tx‐M) measurements. Some participants (n=141) reported ignoring the prohibition of consuming chocolate before platelet testing. Despite having similar baseline characteristics, chocolate consumers had longer PFA closure times (130 vs 123 seconds, P=.005) and decreased Tx‐M levels (175 vs 290 ng/mol creatinine, P=.03). Chocolate remained a significant independent predictor of both ex vivo and in vivo platelet function testing after adjusting for confounders. The authors concluded that even consuming modest amounts of commercial chocolate has important antiplatelet effects.
Estimating the Effect of Protected Lands on the Development and Conservation of Their Surroundings
Authors: McDONALD ROBERT I. , YUAN‐FARRELL CHRIS , FIEVET CHARLES , MOELLER MATTHIAS , KAREIVA PETER , FOSTER DAVID , GRAGSON TED , KINZIG ANN , KUBY LAUREN , REDMAN CHARLES
Published: October 2007

Abstract: The fate of private lands is widely seen as key to the fate of biodiversity in much of the world. Organizations that work to protect biodiversity on private lands often hope that conservation actions on one piece of land will leverage the actions of surrounding landowners. Few researchers have, however, examined whether protected lands do in fact encourage land conservation nearby or how protected lands affect development in the surrounding landscape. Using spatiotemporal data sets on land cover and land protection for three sites (western North Carolina, central Massachusetts, and central Arizona), we examined whether the existence of a protected area correlates with an increased rate of nearby land conservation or a decreased rate of nearby land development. At all sites, newly protected conservation areas tended to cluster close to preexisting protected areas. This may imply that the geography of contemporary conservation actions is influenced by past decisions on land protection, often made for reasons far removed from concerns about biodiversity. On the other hand, we found no evidence that proximity to protected areas correlates with a reduced rate of nearby land development. Indeed, on two of our three sites the development rate was significantly greater in regions with more protected land. This suggests that each conservation action should be justified and valued largely for what is protected on the targeted land, without much hope of broader conservation leverage effects.
Climatic and Biotic Stochasticity: Disparate Causes of Convergent Demographies in Rare, Sympatric Plants
Authors: FOX LAUREL R.
Published: October 2007

Abstract:  Species with known demographies may be used as proxies, or approximate models, to predict vital rates and ecological properties of target species that either have not been studied or are species for which data may be difficult to obtain. These extrapolations assume that model and target species with similar properties respond in the same ways to the same ecological factors, that they have similar population dynamics, and that the similarity of vital rates reflects analogous responses to the same factors. I used two rare, sympatric annual plants (sand gilia [Gilia tenuiflora arenaria] and Monterey spineflower [Chorizanthe pungens pungens]) to test these assumptions experimentally. The vital rates of these species are similar and strongly correlated with rainfall, and I added water and/or prevented herbivore access to experimental plots. Their survival and reproduction were driven by different, largely stochastic factors and processes: sand gilia by herbivory and Monterey spineflower by rainfall. Because the causal agents and processes generating similar demographic patterns were species specific, these results demonstrate, both theoretically and empirically, that it is critical to identify the ecological processes generating observed effects and that experimental manipulations are usually needed to determine causal mechanisms. Without such evidence to identify mechanisms, extrapolations among species may lead to counterproductive management and conservation practices.
Eutrophication and Consumer Control of New England Salt Marsh Primary Productivity
Authors: BERTNESS MARK D. , CRAIN CAITLIN , HOLDREDGE CHRISTINE , SALA NICHOLAS
Published: October 2007

Abstract:  Although primary productivity in salt marshes is thought to be controlled by physical forces, recent evidence suggests that human disturbances can drive a switch to consumer control in these ecologically valuable ecosystems. We tested the hypothesis that nitrogen enrichment can trigger consumer control in salt marshes in Narragansett Bay, Rhode Island, with (1) a field experiment in which we manipulated nutrient availability (with nutrient additions) and insect herbivory (with insecticide application), (2) a survey of 20 salt marshes that examined the relationship between marsh nutrient status and herbivore pressure, and (3) insect herbivore removal at high and low nutrient input sites to directly test the hypothesis that nutrient enrichment is increasing insect herbivory in these marshes. Experimental nitrogen eutrophication initially increased plant productivity but eventually led to reduced plant biomass due to insect herbivory, and our surveys revealed that marsh nitrogen supply was a good predictor of herbivore damage to plants. Insects had minimal impacts on primary productivity in pristine marshes, but suppressed primary productivity in eutrophic salt marshes by 50–75%. Thus, eutrophication is currently triggering consumer suppression of primary productivity in New England salt marshes and may ultimately jeopardize the ecological and societal services these systems provide.
Intellectual and language functions in children of mothers with epilepsy
Authors: Thomas Sanjeev V. , Sukumaran Sajith , Lukose Neetha , George Annamma , Sarma P. S.
Published: October 2007

Summary

Purpose: To compare the intellectual and language functions of children of mothers with epilepsy (CME) with that of controls matched for age and socioeconomic status.

Methods: Cases were CME, aged six years or more (n = 71), drawn from a prospective cohort in the Kerala Registry of Epilepsy and Pregnancy. Controls were 201 children of parents without epilepsy, matched for age and socioeconomic status. The outcome measures included Indian adaptation of Wechsler Intelligence Scale for children and MLT—a locally developed proficiency test for regional language. All relevant data were abstracted from the registry records.

Results: The Full Scale IQ and MLT scores were significantly lower for the cases (87.7 ± 22.6 and 73.4 ± 17.3) compared to controls (93.0 ± 14.4 and 83.2 ± 11.8). Compared to controls, CME scored poor on all subtests of MLT but their impairment was confined to only some of the subtests of IQ. Maternal education and maternal IQ significantly correlated with low IQ and MLT scores for CME whereas type of epilepsy, seizures during pregnancy or low birth weight did not have any significant association with these outcome measures. Polytherapy and higher dosage of antiepileptic drugs (AEDs) were associated with significant impairment in outcome measures. Infants with low developmental quotient at one year of age continued to have low scores on outcome measures at six years.

Conclusions: Low maternal IQ, maternal education, and antenatal AED exposure were associated with significant impairment of intellectual and language functions for CME at six years.
A new animal model of infantile spasms with unprovoked persistent seizures
Authors: Lee Chong L. , Frost James D. , Swann John W. , Hrachovy Richard A.
Published: October 2007

Summary

Purpose: Infantile spasms is one of the most severe epileptic syndromes of infancy and early childhood. Progress toward understanding the pathophysiology of this disorder and the development of effective therapies has been hindered by the lack of a relevant animal model. We report here the creation of such a model.

Methods: The sodium channel blocker, tetrodotoxin (TTX), was chronically infused into the developing neocortex or hippocampus of infant rats by way of an osmotic minipump starting on postnatal day 10–12.

Results: After a minimum of 10 days of infusion, approximately one‐third of these rats began to display very brief (1–2 s) spasms, which consisted of symmetric or asymmetric flexion or extension of the trunk and sometimes involvement of one or both forelimbs. The typical ictal EEG pattern associated with the behavioral spasms consisted of an initial generalized, high amplitude, slow wave followed by an electrodecrement with superimposed fast activity. The interictal EEG revealed multifocal spikes and sharp waves, and in most animals that had spasms a hypsarrhythmic pattern was seen, at least intermittently, during NREM sleep. Like in humans, the spasms in the rat often occurred in clusters especially during sleep–wake transitions. Comparison of the ictal and interictal EEGs recorded in this model and those from humans with infantile spasms revealed that the patterns and the frequency components of both the ictal events and hypsarrhythmia were very similar.

Discussion: The TTX model of infantile spasms should be of value in furthering an understanding of the pathophysiology of this seizure disorder.
Herbal medicine and epilepsy: Proconvulsive effects and interactions with antiepileptic drugs
Authors: Samuels Noah , Finkelstein Yoram , Singer Shepherd Roee , Oberbaum Menachem
Published: October 2007

Summary

The use of complementary and alternative medicine is on the rise, including among patients with epilepsy. Herbal medicine, one of the most popular forms of CAM, is considered to be both safe and effective by most consumers. Yet many herbs may increase the risk for seizures, through intrinsic proconvulsant properties or contamination by heavy metals, as well as via effects on the cytochrome P450 enzymes and P‐glycoproteins, altering antiepileptic drug (AED) disposition. Herb–drug interactions may be difficult to predict, especially since the quality and quantity of active ingredients are often unknown. Since most patients do not inform their physicians that they are taking herbal medicines, health care professionals must initiate a dialogue in order to prevent complications with the combined regimen. At the same time, further research is required regarding the effect of herbs on seizure activity and interactions with AED treatment.
Cognitive Performance in Long‐Term Abstinent Elderly Alcoholics
Authors: Fein George , McGillivray Shannon
Published: October 2007

Background:  To date, there is a wealth of literature describing the deleterious effects of active alcoholism on cognitive function. There is also a growing body of literature on the extent of cognitive recovery that can occur with abstinence. However, there is still a dearth of published findings on cognitive functioning in very long‐term abstinence alcoholics, especially in the elderly population.

Methods:  The current study examines 91 elderly abstinent alcoholics (EAA) (49 men and 42 women) with an average age of 67.3 years, abstinent for an average of 14.8 years (range 0.5 to 45 years), and age and gender comparable light/nondrinking controls. The EAA group was divided into 3 subgroups: individuals that attained abstinence before age 50 years, between the ages 50 and 60 years, and after age 60 years. Attention, verbal fluency, abstraction/cognitive flexibility, psychomotor, immediate memory, delayed memory, reaction time, spatial processing, and auditory working memory were assessed. The AMNART and cranium size were used as estimates of brain reserve capacity, and the association of all variables with alcohol use measures was examined.

Results:  Overall, the EAA groups performed comparably to controls on the assessments of cognitive function. Only the abstinent in group before 50 years of age performed worse than controls, and this was only in the domain of auditory working memory. EAAs had larger craniums than their controls. This effect was strongest for those who drank the longest and had the shortest abstinence. Such individuals also performed better cognitively.

Conclusions:  Our data showed that elderly alcoholics that drank late into life, but with at least 6 months abstinence can exhibit normal cognitive functioning. Selective survivorship and selection bias probably play a part in these findings. Cognitively healthier alcoholics, with more brain reserve capacity, may be more likely to live into their 60s, 70s, or 80s of age with relatively intact cognition, and to volunteer for studies such as this. Our results do not imply that all elderly alcoholics with long‐term abstinence will attain normal cognition.
Motor Functioning and Alcohol Dependence
Authors: De Wilde Bieke , Dom Geert , Hulstijn Wouter , Sabbe Bernard
Published: October 2007

Background:  Autopsy and neuroimaging research in stably abstinent alcoholics illuminated structural and functional abnormalities in brain areas that organize and coordinate motor functioning. Researchers that used behavioural tasks to measure motor functioning found that abstinent alcoholics perform worse than healthy controls. These researchers however did not analyze timed responses into their cognitive and motor components. They thus were unable to decide which aspects of information processing are impaired. We here used a Fitts’ task to examine differences in cognitive and motor components between abstinent alcoholics and healthy controls.

Methods:  Fifty‐two abstinent alcoholics and 52 healthy controls participated in this research design. Fine motor functioning was assessed by means of the Fitts’ task.

Results:  Abstinent alcoholics needed more time to perform timed responses than healthy controls. As both reaction and movement times were higher in abstinent alcoholics, both cognitive and motor processes seem to be impaired. When the task became more difficult (small targets instead of large targets) abstinent alcoholics needed proportionally more time to give the correct response than healthy controls. This phenomenon solely applied to movement times.

Conclusions:  These research data indicate that abstinent alcoholics are somewhat impaired on a behavioral level. The execution of timed responses indeed was lengthier in abstinent alcoholics than in healthy controls. As both cognitive and motor processes were impaired, we here assume that both central and peripheral processes are affected by progressive alcohol intake. Abstinent alcoholics also have more difficulties to adapt their motor responses to changing task conditions.
Variation in GABRA2 Predicts Drinking Behavior in Project MATCH Subjects
Authors: Bauer Lance O. , Covault Jonathan , Harel Ofer , Das Sourish , Gelernter Joel , Anton Raymond , Kranzler Henry R.
Published: October 2007

Background:  Previous studies demonstrated, and replicated, an association between single nucleotide polymorphisms (SNPs) within the GABRA2 gene and risk for alcohol dependence. The present study examines the association of a GABRA2 SNP with another definition of alcohol involvement and with the effects of psychosocial treatment.

Methods:  European‐American subjects (n = 812, 73.4% male) provided DNA samples for the analysis. All were participants in Project Matching Alcoholism Treatment to Client Heterogeneity (MATCH), a multi‐center randomized clinical trial evaluating the efficacy of 3 types of psychosocial treatment for alcoholism: Cognitive Behavioral Therapy (CBT), Motivational Enhancement Therapy (MET), or twelve‐step facilitation (TSF). The daily probabilities of drinking and heavy drinking were estimated during the 12‐week treatment and 12‐month post‐treatment periods.

Results:  Subjects homozygous for the allele associated with low risk for alcohol dependence in previous studies had lower daily probabilities of drinking and heavy drinking in the present study. This low‐risk allele was also associated with a greater difference in drinking outcomes between the treatments. In addition, it enhanced the relative superiority of TSF over CBT and MET. Population stratification was excluded as a confound using ancestry informative marker analysis.

Conclusions:  The assessment of genetic vulnerability may be relevant to studies of the efficacy of psychosocial treatment: GABRA2 genotype modifies the variance in drinking and can therefore moderate power for resolving differences between treatments.