threshold effects in price transmission the case of brazilian wheat maize and soya prices recent studies into price transmission have recognized the important role played by transport and transaction costs threshold models are one approach to accommodate such costs we develop a generalized threshold error correction model to test for the presence and form of threshold behavior in price transmission that is symmetric around equilibrium we use monthly wheat maize and soya prices from the united states argentina and brazil to demonstrate this model classical estimation of these generalized models can present challenges but bayesian techniques avoid many of these problems evidence for thresholds is found in three of the five commodity price pairs investigated

distinguishing between equilibrium and integration in spatial price analysis this article introduces a new spatial price analysis methodology based on maximum likelihood estimation of a mixture distribution model incorporating price transfer cost and trade flow data this method permits differentiation between market integration and competitive market equilibrium and derivation of intuitive measures of intermarket tradability competitive market equilibrium perfect integration segmented equilibrium and segmented disequilibrium one can also use these estimates to derive semiparametric measures of time varying regime probabilities to track changing market conditions an application to trade in soybean meal among pacific rim economies demonstrates the usefulness of the method copyright 2002 oxford university press

on the sources of aggregate fluctuations in emerging economies recent research on macroeconomic fluctuations in emerging economies has advocated introducing a stochastic productivity trend or allowing for interest rate shocks and financial frictions we estimate a model that encompasses these two approaches shedding light on their relative merits and on how financial frictions affect the transmission of shocks the model accounts for aggregate fluctuations by assigning a dominant role to financial frictions in amplifying conventional temporary productivity shocks whereas trend shocks play a minor role a link between spreads and expected future productivity emerges as essential for a reasonable approximation to the data

bayesian estimation and selection of nonlinear vector error correction models the case of the sugar ethanol oil nexus in brazil nonlinear adjustment toward long run price equilibrium relationships in the sugar ethanol oil nexus in brazil is examined we develop generalized bivariate error correction models that allow for cointegration between sugar ethanol and oil prices where dynamic adjustments are potentially nonlinear functions of the disequilibrium errors a range of models are estimated using bayesian monte carlo markov chain algorithms and compared using bayesian model selection methods the results suggest that the long run drivers of brazilian sugar prices are oil prices and that there are nonlinearities in the adjustment processes of sugar and ethanol prices to oil price but linear adjustment between ethanol and sugar prices

measuring market integration in the presence of transaction costs a threshold vector error correction approach applied econometric analyses of market integration based on price data alone have been criticised because they neglect the role of transaction costs to meet this objection threshold vector error correction models are used threshold models can account for the effects of transaction costs in price transmission without directly relying upon information about these costs which are often unavailable it is argued that threshold models that are based on two thresholds provide results that are economically more intuitive than those obtained from one threshold models however to this point no adequate econometric test is available for threshold significance in a two threshold model such tests are only available for the one threshold model in this paper a restricted two threshold model is developed in which the significance of the thresholds can be tested this model is therefore amenable to economic interpretation and statistical inference the model is used to estimate market integration in the european pig market

determination of the international maize price what is the growing role of brazil and ukraine this paper examines the relationships among maize prices for four countries to determine if newly emerging exporters brazil and ukraine influence the international price of maize our work focuses on each market s participation in the price discovery process rather than trying to determine a price leader we find that the united states plays the largest role in price discovery followed by argentina brazil and ukraine we also search for export thresholds and find that ukraine s contribution to price discovery rises slightly when an export threshold of 2 3 million tons is reached no export thresholds were found for brazil export thresholds for argentina were found but only have a minor impact on price relationships we also found that price relationships vary considerably across seasons of the year

cointegration tests and spatial price linkages in regional cattle markets this analysis empirically evaluates spatial linkages in regional cattle markets using cointegration tests of regional price series several markets were not cointegrated over the 1980 through 1987 period however significant increases in cointegration of several regional livestock markets are observed through the 1980s the increased cointegration parallels significant structural changes in the livestock industry a formal analysis of market characteristics reveals that distances between markets industry concentration ratios market volumes and market types have significant influences on cointegration relationships between markets

acreage decisions under risk the case of corn and soybeans an acreage supply response model is developed under expected utility maximization the resulting framework is used to specify and estimate a system of risk responsive acreage equations for corn and soybeans in the united states particular attention is given to the truncation effects of government price supports on the distribution of corn and soybean prices also a wealth variable is included in the acreage equations the empirical results indicate that risk and wealth variables play an important role in cornsoybean acreage decisions the analysis also shows that cross commodity risk reduction is important in acreage allocation decisions

sharing a ride on the commodities roller coaster common factors in business cycles of emerging economies fluctuations in commodity prices are an important driver of business cycles in small emerging market economies emes this paper documents how these fluctuations correlate strongly with the business cycle in emes a commodity sector is then embedded into a multi country emes business cycle model where exogenous fluctuations in commodity prices follow a common dynamic factor structure and coexist with other driving forces the estimated model assigns to commodity shocks 42 percent of the variance in income of which a considerable part is linked to the common factor a further amplification mechanism is a spillover effect from commodity prices to risk premia

testing market integration a model of spatial price differentials for a tradable good is proposed which avoids the inferential dangers of received methods using static price correlations the proposed method also extracts more information on the causes of price differentials from the same data the method is illustrated using monthly rice price data for postindependence bangladesh including the very substantial regional price shocks during the 1974 famine impediments to market integration are indicated

limits of floating exchange rates the role of foreign currency debt and import structure abstract a traditional argument in favor of flexible exchange rates is that they insulate output better from real shocks because the exchange rate can adjust and stabilize demand for domestic goods through expenditure switching this argument is weakened in models with high foreign currency debt and low exchange rate pass through to import prices the present study evaluates the empirical relevance of these two factors we analyze the transmission of real external shocks to the domestic economy under fixed and flexible exchange rate regimes for a broad sample of countries in a panel var and let the responses vary with foreign currency debt and import structure we find that flexible exchange rates do not insulate output better from external shocks if the country imports mainly low pass through goods and foreign indebtedness is high

global growing area elasticities of key agricultural crops estimated using dynamic heterogeneous panel methods we estimate the short and long run global response of corn soybeans wheat and rice growing areas to output price changes allowing responses to vary across countries using methods from the panel time series literature our estimates of growing area response are considerably lower than estimates obtained using more traditional models previous findings appear biased due to the assumption of homogeneous response across countries our aggregate estimates of short and long run elasticities of four crop growing areas with respect to average price are 0 024 and 0 143 respectively crop specific results indicate that both corn and soybean growing areas are generally more responsive than wheat and rice for corn and soybeans the long run own price growing area elasticities are 0 274 and 0 793 respectively the long run own price elasticities for wheat and rice are 0 279 and 0 045 respectively the short run own price elasticities for corn and soybeans are 0 133 and 0 199 respectively which are higher than wheat 0 037 and rice 0 00001

dynamic asymmetries in u s unemployment we examine dynamic asymmetries in u s unemployment using nonlinear time series models and bayesian methods we find strong statistical evidence in favor of a two regime threshold auto regressive model empirical results indicate that once we take into account both parameter and model uncertainty there are economically interesting asymmetries in the unemployment rate one finding of particular interest is that shocks that lower the unemployment rate tend to have a smaller effect than shocks that raise the unemployment rate this finding is consistent with unemployment rises being sudden and falls gradual

saving growth and investment a macroeconomic analysis using a panel of countries this paper provides a descriptive analysis of the long and short run correlations among saving investment and growth rates for 123 countries over the period 1961 94 three results are robust across data sets and estimation methods i lagges saving rates are positively related to investment rates ii investment rates granger cause growth rates with a negative sign iii growth rates granger cause investment with a positive sign

the transmission of world maize price to south african maize market a threshold cointegration approach this article seeks to provide an explanation for the relationship between domestic maize price in south africa and world maize prices in order to evaluate comovement and transmission of world prices to domestic prices in sub sahara african countries this is done by comparing nested and nonnested models that capture different forms of nonlinearity in the price spread adopting a bayesian approach that allows for comparison of models using bayes factor we found that the relationship between south african price and world price for maize indicates the presence of nonlinearity in price transmission with three regimes that is triggered by the price spread in previous period

estimating policy effects on spatial market efficiency an extension to the parity bounds model the standard parity bounds model pbm is extended to allow for dynamic shifts in regime probabilities in response to changes in marketing policy the approach allows estimation of the length of the adjustment period and a statistical test for no policy effects the extended pbm is applied to maize and wheat markets in ethiopia evidence of a dynamic adjustment path is found and grain marketing reforms are found to have improved spatial efficiency in a few markets worsened it in a few others but generally to have had little effect on the spatial efficiency of ethiopian grain markets

reaching out access to and use of banking services across countries the authors 1 present new indicators of banking sector penetration across 99 countries based on a survey of bank regulatory authorities 2 show that these indicators predict household and firm use of banking services 3 explore the association between the outreach indicators and measures of financial institutional and infrastructure development across countries and 4 relate these banking outreach indicators to measures of firms financing constraints in particular they find that greater outreach is correlated with standard measures of financial development as well as with economic activity controlling for these factors the authors find that better communication and transport infrastructure and better governance are also associated with greater outreach government ownership of financial institutions translates into lower access while more concentrated banking systems are associated with greater outreach finally firms in countries with higher branch and atm penetration and higher use of loan services report lower financing obstacles thus linking banking sector outreach to the alleviation of firms financing constraints

worldwide acreage and yield response to international price change and volatility a dynamic panel data analysis for wheat rice corn and soybeans this study estimates a worldwide aggregate supply response for key agricultural commodities namely wheat rice corn and soybeans by employing a newly developed multi country crop and calendar specific seasonally disaggregated model with price changes and price volatility applied accordingly the findings reveal that although higher output prices serve as incentives to improve global crop supply as expected output price volatility acts as a disincentive depending on the crop the results show that own price supply elasticities range from about 0 05 to 0 40 output price volatility however has negative correlations with crop supply implying that farmers shift land other inputs and yield improving investments to crops with less volatile prices simulating the impact of price dynamics since 2006 we find that price risk has reduced the production response of wheat in particular and to a lesser extent rice thus dampening price incentive effects the simulation analysis shows that the increase in own crop price volatility during the 2006 2010 period has dampened yield by about 1 2 for the crops considered

business cycle implications of rising household credit market participation in emerging countries abstract a small open emerging economy model is extended with a household sector financial constraint to investigate business cycle implications of a rise in household access and use of financial services estimating the model on mexican data and consistent with empirical findings this paper finds that a rise in household credit market participation 1 yields larger aggregate consumption volatility and 2 amplifies the effects of shocks in the domestic economy particularly those transmitted through the interest rate channel the estimated model also highlights that 3 the lesser financial frictions are the lower is the increase of consumption growth and trade balance volatility driven by a rise in household credit market participation and 4 trend productivity shocks become a more relevant source of business cycle fluctuations finally standard measures of predictive accuracy suggest that the extended model outperforms the baseline emerging market model

market analysis methods are our enriched toolkits well suited to enlivened markets the past fifteen years have brought historic reduction of government intervention in agricultural markets in the developing world most economists and policy makers believe these reforms enliven markets previously fettered by excessive government authority nonetheless the impact of market oriented reforms on the spatial and intertemporal extent and the competitiveness of markets remains an inherently empirical question meanwhile there also have been major innovations in methods used to analyze markets and prices due largely to the rapidly emerging time series econometric literature agricultural economists toolkits have changed nearly as rapidly and dramatically as have developing economy markets but can these enriched toolkits answer the

the extent of the market examines the classical theory of the market in this paper authors consider the role of price market determination price movement in competitive and monopolistic markets extension of commodity markets

the new keynesian transmission mechanism a heterogenous agent perspective we present a tractable heterogeneous agent version of the new keynesian model that allows us to study the interaction between inequality and monetary policy though formulated as a precautionary saving model a la huggett aiyagari its reduced form is a two agent model with a highly concentrated wealth distribution when prices are sticky and wages flexible as in the textbook representative agent model monetary policy affects the distribution of consumption but has no effect on output as workers choose not to change their hours worked in response to wage movements this highlights a transmission mechanism of the textbook model that we find implausible in response to a monetary stimulus the representative worker s labor supply is greatly affected by the profits she receives first the lower profits induced by higher wages raise labor supply through a wealth effect and secondly the mere presence of profits reduces the negative income effect of a wage rise when wages are rigid in contrast our model exhibits plausible responses of output and hours worked to monetary policy shocks

the impact of rising ethanol production on the brazilian market for basic food commodities an econometric assessment the controversial debate on the impacts of rising biofuel production on food commodity markets is of great policy relevance in brazil this paper contributes to the discussion by applying panel data regression models with fixed effects using ols our dataset comprises annual production harvested area data for sugar ethanol and five other staple commodities ranging from 1981 to 2009 for 24 brazilian states our results indicate that rising ethanol production exerts statistically significant positive impacts on sugarcane negative impacts on rice beans and soybeans acreage but no statistically significant effect on the areas for corn and manioc the negative impacts on commodities acreage have implications for the associated prices ceteris paribus rising ethanol production puts some upward pressure on the prices for rice beans and soybeans however the economic implication of these direct land use effects is attenuated due to the moderate scale of any effect

the economics of brazil s ethanol sugar markets mandates and tax exemptions sugarcane in brazil is processed into sugar and or ethanol often in flex plants that can switch between the two products we develop an economic model of flex plants export demands and two domestic fuel demand curves for a blend of ethanol with gasoline consumed by conventional cars and ethanol consumed only by flex cars we analyze the market impacts of the following policies the blend mandate fixing gasoline prices below world prices the high gasoline tax and a higher tax exemption for ethanol blended with gasoline because brazilian and u s ethanol prices have become linked a change in brazilian ethanol policy or a shock in world sugar markets can now impact u s ethanol and corn prices we show that in theory each policy analyzed has an ambiguous impact on ethanol and sugar prices empirically however a low gasoline tax and a high tax exemption for ethanol used in the fuel blend reduce ethanol and sugar prices this contradicts conventional wisdom overall we find that policy reforms implemented in 2010 offset the ethanol price increase by about 27 due to outward shifts in fuel transportation and sugar export demand curves and due to a reduced sugarcane supply caused by bad weather our model illustrates the importance of brazil s ethanol policies on world commodity markets it also provides insight into how the brazilian government can adjust policies to better control domestic inflation while minimizing impacts on investment

world shocks world prices and business cycles an empirical investigation abstract svar models that include a single world price such as the terms of trade predict that world shocks explain a small fraction of movements in domestic output typically less than 10 this paper presents an empirical framework in which multiple commodity prices transmit world disturbances estimates on a panel of 138 countries over the period 1960 2015 indicate that world shocks explain on average 33 of output fluctuations in individual economies this figure doubles when the model is estimated on post 2000 data the findings reported here suggest that one world price specifications significantly underestimate the importance of world shocks for domestic business cycles

asset market participation monetary policy rules and the great inflation this paper argues that limited asset market participation is crucial in explaining u s macroeconomic performance and monetary policy before the 1980s and their changes thereafter in an otherwise conventional sticky price model standard aggregate demand logic is inverted at low enough asset market participation interest rate increases become expansionary passive monetary policy ensures equilibrium determinacy and maximizes welfare this suggests that federal reserve policy in the pre volcker era was better than conventional wisdom implies we provide empirical evidence consistent with this hypothesis and study the relative merits of changes in structure and shocks for reproducing the conquest of the great inflation and the great moderation

spatial price transmission and asymmetry in the ghanaian maize market abstract this paper utilizes recently developed threshold cointegration tests that allow for asymmetric adjustment toward a long run equilibrium relationship to examine price linkages between principal maize markets in ghana unlike previous studies the approach employed here assumes that economic agents only act to move the system back to equilibrium when the deviation from equilibrium exceeds a critical threshold whereby the benefits of this adjustment exceed the costs the findings indicate that major maize markets in ghana are well integrated both the threshold cointegration and asymmetric error correction models reveal that wholesale maize prices in local markets accra and bolgatanga respond more swiftly to increases than to decreases in central market techiman prices accra prices are found to react faster than bolgatanga prices to changes in techiman market prices

biofuels and land use change sugarcane and soybean acreage response in brazil scientists and economists are increasingly worried that biofuels production is leading to land use changes in the form of competition with food crops or loss of natural ecosystems i estimate acreage conversion in response to shocks in sugarcane a biofuels feedstock and soybean thought to be affected by united states corn ethanol production prices in brazil at a national and regional level using county level data from 1973 to 2005 i consider a dynamic panel data model of input demand for agricultural land conditioning on price changes of other commodities the short run crop price elasticity of sugarcane acreage in brazil is estimated to be approximately zero whereas the elasticity of soybean acreage is 0 9 when both spot and futures prices change the regional estimates for soybeans show considerable variation and are highest in areas of ecological importance such as the cerrado sugarcane estimates are more homogeneous these results should be taken into account in impact assessments of biofuels

futures prices in supply analysis are instrumental variables necessary citation nathan p hendricks joseph p janzen aaron smith futures prices in supply analysis are instrumental variables necessary american journal of agricultural economics volume 97 issue 1 1 january 2015 pages 22 39 https doi org 10 1093 ajae aau062

inter and intra seasonal crop acreage response to international food prices and implications of volatility understanding how producers make decisions to allot acreage among crops and how decisions about land use are affected by changes in prices and their volatility is fundamental for predicting the supply of staple crops and hence assessing the global food supply situation this study makes estimations of monthly i e seasonal versus annual global acreage response models for the world s principal staple food crops wheat corn soybeans and rice primary emphasis is given to the magnitude and speed of the allocation process estimation of intra annual acreage elasticity is crucial for expected food supply and for input demand especially in the light of the recent short term volatility in food prices the econometric results indicate that global crop acreage responds to crop prices and price risks input costs as well as a time trend depending on respective crop short run elasticities are about 0 05 to 0 40 price volatility tends to reduce acreage for some of the crops comparison of the annual and the monthly acreage response elasticities suggests that acreage adjusts seasonally around the globe to new information and expectations given the seasonality of agriculture time is of an essence for acreage response the analysis indicates that acreage allocation is more sensitive to prices in the northern hemisphere spring than in winter and the response varies across months

modelling trends in food market integration method and an application to tanzanian maize markets abstract pushed by increasing availability of price data and extensive market liberalisation efforts in many developing countries research on food market integration has evolved rapidly over the last two decades empirical methods to measure market integration diverged in two directions on the one hand there is the parity bounds model pbm using a switching regressions technique while on the other hand the use of threshold autoregressive tar models has been proposed this article provides a discussion on the two methods and argues that tar models are better able to capture the dynamics of the arbitrage process underlying interconnected markets furthermore we extend the standard tar model to include a time trend in both the threshold and the adjustment parameter using weekly maize price data on seven selected markets in tanzania we illustrate how both transaction cost and the speed of adjustment have changed during the nineties

limited asset markets participation monetary policy and inverted aggregate demand logic abstract this paper incorporates limited asset markets participation in dynamic general equilibrium and develops a simple analytical framework for monetary policy analysis aggregate dynamics and stability properties of an otherwise standard business cycle model depend nonlinearly on the degree of asset market participation while moderate participation rates strengthen the role of monetary policy low enough participation causes an inversion of results dictated by conventional wisdom the slope of the is curve changes sign the taylor principle is inverted optimal welfare maximizing discretionary monetary policy requires a passive policy rule and the effects and propagation of shocks are changed however a targeting rule implementing optimal policy under commitment delivers equilibrium determinacy regardless of the degree of asset market participation our results may justify fed s behavior during the great inflation period

the effects of financial development in the short and long run theory and evidence from india abstract although many view financial access as a means of reducing poverty or increasing growth empirical studies have produced contradictory results one problem is that most studies cover only a short time frame and do not consider dynamic effects i show that introducing credit in a general model of intertemporal consumption creates a boom in consumption and reduces poverty initially but eventually reduces mean consumption because credit substitutes for precautionary wealth using new consistent consumption data that cover a much longer time period than most studies my empirical findings show that increased access to bank branches in rural india increased consumption initially and reduced poverty but consumption later fell and poverty rose the long term effect is still positive however suggesting that credit may have a beneficial role beyond consumption smoothing

convergence of the static estimation toward the long run effects of dynamic panel data models abstract this article focuses on the estimation of long run effects on panel data we show that the probability limit of the between estimator of a static relation whereas the true specification is a dynamic error components model converges to the long run effects

transfer costs spatial arbitrage and testing for food market integration conventional tests for food market integration ask often misleadingly whether prices in different locations move together in this paper an alternative methodology the parity bounds model pbm is developed which uses information on transfer costs in addition to food prices to assess the efficiency of spatial arbitrage monte carlo experiments using data generated by a point space spatial price equilibrium model show the pbm to be statistically reliable an application to philippine rice markets demonstrates that the pbm detects efficient arbitrage when other tests do not

market integration efficiency of arbitrage and imperfect competition methodology and application to u s celery this paper develops and applies a methodology to test for efficiency of interregional commodity arbitrage application of the methodology requires only time series data on prices for alternative cities regions countries or product forms yet the approach is capable of generating evidence on a number of market parameters including market integration arbitrage efficiency the magnitude of marketing margins product substitutability and competitiveness of markets estimation is based on a switching regression model with three regimes efficient arbitrage relative shortage and relative glut results from application of the model to u s celery marketing indicated significant departures from efficient arbitrage for both california and florida celery

does the law of one price really hold for commodity prices in spite of the empirical failure of the law of one price it is usually assumed that commodity prices are perfectly arbitraged at least in the long run this paper argues that this assumption is counterfactual and that much of the empirical evidence provided to support it is flawed and affected by econometric shortcomings spurious regressions nonstationarity in the data inappropriate use of first differences an alternative methodology co integration by which a long run relationship between nonstationary series can be tested is proposed tests of nonstationarity and co integration for a group of commodities show quite uniformly that the law of one price as a long run relationship fails and that deviations from the pattern are permanent

commodity booms and busts in emerging economies abstract emerging economies particularly those dependent on commodity exports are prone to highly disruptive economic cycles this paper proposes a small open economy model for a net commodity exporter to quantitatively study the triggers of these cycles the economy consists of two sectors one of which produces commodities with prices subject to exogenous international fluctuations these fluctuations affect both the competitiveness of the economy and its borrowing terms as higher commodity prices are associated with lower spreads between the country s borrowing rate and world interest rates both effects jointly result in strongly positive effects of commodity price increases on gdp consumption and investment and a negative effect on the total trade balance furthermore they generate excess volatility of consumption over output and a large volatility of investment besides explicitly incorporating a double role of commodity prices the model structure nests the various candidate sources of shocks proposed in previous work on emerging economy business cycles estimating the model on argentine data we find that the contribution of commodity price shocks to fluctuations in post 1950 output growth is in the order of 38 in addition commodity prices account for around 42 and 61 of the variation in consumption and investment growth respectively we find transitory productivity shocks to be an important driver of output fluctuations exceeding the contribution of shocks to the trend which though smaller is not negligible

cross country maize market linkages in africa integration and price transmission across local and global markets in order to study short run price shock propagation we model twenty seven sub saharan africa ssa domestic maize markets within a global vector autoregression framework the main purpose is to fully embed multilateral trade flows as a way to better structure local price transmission dynamics and interdependencies and get a more comprehensive picture of food price shocks propagation we found significant between country market contagion and prompt regional price shock propagation when trade connection exists yet the integration of ssa domestic maize markets within the continent and with global markets remains generally weak furthermore under regular market conditions most local price series appear to be more responsive to regional neighbors than to global shocks

spatial market integration in the presence of threshold effects a large body of research has evaluated price linkages in spatially separate markets much recent research has applied models appropriate for nonstationary data such analyses have been criticized for their ignorance of transactions costs which may inhibit price adjustments and thus affect tests of integration this analysis utilizes threshold autoregression and cointegration models to account for a neutral band representing transactions costs we evaluate daily price linkages among four corn and four soybean markets in north carolina nonlinear impulse response functions are used to investigate dynamic patterns of adjustments to shocks our results confirm the presence of thresholds and indicate strong support for market integration though adjustments following shocks may take many days to be complete in every case the threshold models suggest much faster adjustments in response to deviations from equilibrium than is the case when threshold behavior is ignored a large amount of empirical research has evaluated the extent to which spatially separate markets are integrated though the term is used loosely in the literature tests of market integration usually consider the extent to which shocks are transmitted among spatially separate markets the integration of markets can have important implications for price discovery and the operation of the market since persistent deviations from integration may imply riskless profit opportunities for spatial traders

spatial price efficiency in mozambique s post reform maize markets maize zea mays shortages and maize price instability continue to occur in mozambique in spite of policy reforms and great capacity for increased production in northern mozambique this study measured the efficiency of spatial maize price arbitrage in mozambique s post reform period spatial price inefficiency does not seem to explain why food shortages continue to occur in mozambique suggesting nonprice market constraints such as poor infrastructure and poor market institutions as more likely explanations baulch s spatial efficiency test indicated that it is not profitable to ship maize from northern surplus maize regions to southern mozambique records of interregional maize shipments show that indeed grain is not being shipped from the north to the south market liberalization may have improved spatial price efficiency but high transfer costs still limit trade and potential benefits from freeing markets under these circumstances food shortages and price instability are likely to continue

multiple regime spatial price transmission with an application to maize markets in southern africa conventional threshold models of price transmission allow for different speeds of adjustment to equilibria depending on the magnitude of price differentials between markets however these models typically assume only one underlying long run equilibrium price relationship in this article we develop a framework for allowing multiple equilibria and multiple speeds of adjustment with regime separation depending on the magnitude of trade flows between regions rather than the magnitude of price differentials applying this framework to maize price transmission between south africa and zambia shows no transmission during periods of high imports when the government was heavily involved in maize importation but stronger transmission during periods of low imports when the government was not importing copyright 2012 oxford university press

the structure of technology in brazilian sugarcane production 1975 87 an application of a modified symmetric generalized mcfadden cost function sugarcane based ethanol has become a primary automotive fuel in brazil over the past 15 years because sugarcane costs are over two thirds of the costs of ethanol production the economic efficiency of this renewable petroleum substitute hinges on the structure of technology in sugarcane production in this paper a modified symmetric generalized mcfadden sgm cost function for sugarcane is estimated and the presence of technical change and economies of scale are investigated the original sgm proposed by diewert and wales 1987 is modified to allow for fixed factors of production this allows the cost function to be applied to processes which have fixed factors the results suggest that there is no empirical evidence of economies of scale and very little technical change only in the north of brazil the implications for the future economic efficiency of this petroleum substitute are discussed