agriculture led growth foodgrains versus export crops in madagascar abstract this article compares the growth generating power of alternative agricultural development strategies in madagascar projections from a semi input output model and a recently developed social accounting matrix suggest that both paddy and export crops stimulate strong linkages with other sectors of the malagasy economy but since paddy output can be increased at lower cost investment in rehabilitating small irrigated rice perimeters generates 40 to 100 more gdp than a comparable investment in coffee production paddy also generates greater employment and a more equitable income distribution

sensitivity analyses of anomalies in developed stock markets abstract the literature on anomalies in developed stock markets produces no consensus on specification this study uses extreme bound analysis eba to evaluate the robustness of 15 stock return anomalies given data covering 16 developed markets from may 1984 to march 1999 two factors are sturdy according to the extreme decision rule in the panel design d p and momentum under a less stringent eba criterion long run lagged returns country risk and the january effect are also robust time series eba for individual markets produces one robust result according to relaxed decision rules across a majority of cases long run government bond yields

market clearing with stochastic security part i formulation the first of this two paper series formulates a stochastic security constrained multi period electricity market clearing problem with unit commitment the stochastic security criterion accounts for a pre selected set of random generator and line outages with known historical failure rates and involuntary load shedding as optimization variables unlike the classical deterministic reserve constrained unit commitment here the reserve services are determined by economically penalizing the operation of the market by the expected load not served the proposed formulation is a stochastic programming problem that optimizes concurrently with the pre contingency social welfare the expected operating costs associated with the deployment of the reserves following the contingencies this stochastic programming formulation is solved in the second companion paper using mixed integer linear programming methods two cases are presented a small transmission constrained three bus network scheduled over a horizon of four hours and the ieee reliability test system scheduled over 24 h the impact on the resulting generation and reserve schedules of transmission constraints and generation ramp limits of demand side reserve of the value of load not served and of the constitution of the pre selected set of contingencies are assessed

economies of scope and the cash crop food crop debate in senegal abstract the government of senegal plans to achieve national food self sufficiency by inducing farmers to switch away from cash crops toward food crop production this paper examines selected economic consequences of the planned substitution using empirical data recently collected in southeastern senegal cost function estimates suggest that farmers are currently producing too much food crop and too little cash crop output given existing technology and observed relative prices moreover economies of scope in producing both food crops and cash crops on the same farm result in a 22 cost saving relative to growing both types of crops on separate specialized farms

genco s risk constrained hydrothermal scheduling this paper presents a stochastic midterm risk constrained hydrothermal scheduling algorithm in a generation company genco the objective of a genco is to maximize payoffs and minimize financial risks when scheduling its midterm generation of thermal cascaded hydro and pumped storage units the proposed schedule will be used by the genco for bidding purposes to the iso the optimization model is based on stochastic price based unit commitment the proposed genco solution may be used to schedule midterm fuel and natural water inflow resources for a few months to a year the proposed stochastic mixed integer programming solution considers random market prices for energy and ancillary services as well as the availability of natural water inflows and generators in monte carlo scenarios financial risks associated with uncertainties are considered by applying expected downside risks which are incorporated explicitly as constraints variable time steps are adopted to avoid the exponential growth in solution time and memory requirements when considering midterm constraints a single water to power conversion function is used instead of several curves for representing water head and discharge parameters piecewise linearized head dependant water to power conversion functions are used for computational efficiency illustrative examples examine gencos midterm generation schedules risk levels fuel and water usage and hourly generation dispatches for bidding in energy and ancillary services markets the paper shows that gencos could decrease their financial risks by adjusting expected payoffs

the future of asean energy mix a swot analysis this paper assesses competing outlooks for energy mix in the association of southeast asian nations asean highlighting the paradox of its fossil fuel dominated outlooks when contrasted with its aspirations to move toward a green energy mix and reviews green energy strategies using the strengths weaknesses opportunities and threats swot analysis method the paper argues that despite the looming brown outlooks due to the expected surge of coal the asean region has many advantages in providing cleaner energy for its green vision however reduction of co2 emissions has not been explicitly set in the region s policy agenda and thus green energy potential is underdeveloped to achieve a greener energy mix asean needs to make further efforts such as cleaner use and removal of subsidies of fossil fuels promotion of renewables and energy efficiency regional market integration and connectivity and execution of existing plans by nations ultimately each of these strategies will require sustained leadership political determination and concrete actions from stakeholders in particular national governments across the region

portfolio analysis with factors and scenarios recently there has been a growing interest in the scenario model of covariance as an alternative to the one factor or many factor models we show how the covariance matrix resulting from the scenario model can easily be made diagonal by adding new variables linearly related to the amounts invested note the meanings of these new variables note how portfolio variance divides itself into within scenario and between scenario variances and extend the results to models in which scenarios and factors both appear where factor distributions and effects may or may not be scenario sensitive

agriculture in recent development theory abstract this paper is a critical review of recent contributions to the literature on agriculture in development theory it considers and compares the main lines of advance made within neoclassical neo marxian and structuralist approaches recent neo marxian and structuralist studies of agrarian development reveal that traditional agriculture is neither stationary nor efficient that resource allocation cannot be separated from wealth distribution or production organization that forms of surplus appropriation do not necessarily follow the dictates of efficiency that the social relations of production may inhibit accumulation and determine the forms of technological change that the state s role in primitive accumulation is more economic than explicitly coercive political and that political and macroeconomic constraints preclude a simple get the prices right view of the intersectoral terms of trade the thrust of these developments is to challenge both neoclassical and some orthodox marxian formulations of agrarian development issues and add to the insights to be gleaned from a political economy of development

agricultural commercialization and nutrition revisited empirical evidence from three african countries the transition from subsistence to commercial agriculture is key for economic growth but what are the consequences for nutritional outcomes the evidence to date has been scant and inconclusive this study contributes to the debate by revisiting two prevailing wisdoms a market participation by african smallholders remains low and b the impact of commercialization on nutritional outcomes is generally positive using nationally representative data from three african countries the analysis reveals high levels of commercialization by even the poorest and smallest landholders with rates of market participation as high as 90 female farmers participate less but tend to sell larger shares of their production conditional on participation second we find little evidence of a positive relationship between commercialization and nutritional status as countries and international agencies prioritize the importance of nutrition sensitive agriculture better understanding of the transmission channels between crop choices and nutritional outcomes should remain a research priority

regional growth linkages from agriculture pioneering research on downstream linkages from agriculture is said to demonstrate that consumption links rather than production links are the main source of indrect growth effects that these consumption links take the form of labour intensive goods and services produced locally and that the largest farm enterprises are most locally multiplicative of activities mopping up surplus rural labour this article has two purposes first the methodologies assumptions and data base for the quantification of the local and non local regional multiplier effects from agricultural development are examined second the contradictory interpretations for agricultural policy which have arisen from these exercises of quantification are discussed and an attempt made to explain their bases

can land market reform mitigate the exclusionary aspects of rapid agro export growth abstract agro export growth has been associated with land concentration and employment instability in the wake of exclusionary agro export booms land market reform has been proposed as a way to improve peasant land access through the market developing a model of the economic competitiveness of different classes of producers this paper evaluates the likely effectiveness of land market reform while the model itself gives ambiguous answers numerical simulation identifies a large gap between market price and peasants abilty to pay for land among the components of land market reform policy progressive land taxation appears unlikely to close that competitiveness gap while farm land mortgage banks appear more likely to mitigate exclusionary aspects of growth

market clearing with stochastic security part ii case studies this paper analyzes the market clearing formulation with stochastic security developed in its companion paper through two case studies solved using mixed integer linear programming techniques the generation and reserve schedules as well as the nodal prices of energy and security are assessed under various conditions such as a line flow limits b when nonspinning reserve is excluded from the formulation c demand side valuation of energy not served d generator ramping limits and e the set of pre selected contingencies

trends cycles and asymmetries in the terms of trade of primary commodities from developed and less developed countries abstract the paper examines the prebisch hypothesis that primary product prices relative to the price of manufacturers fall during cyclical downturns by more than they rise during cyclical upturns and that this is an independent explanation of the secular tendency of the net barter terms of trade to move against primary commodities an important distinction is made between primary products exported by less developed countries and those exported by developed countries the greater cyclicality of primary product prices and the long run deterioration in their terms of trade since 1954 are confirmed but there is little support for the prebisch thesis that primary product prices relative to manufacturers are move sensitive on the downswing than the upswing

cash crops and food security evidence from ethiopian smallholder coffee producers one of the central questions in food policy debates has been the role of cash cropping for achieving food security in low income countries we revisit this question in the context of smallholder co

uncertainty and disaster avoidance behaviour in peasant farming evidence from bangladesh a sample of smallholding farmers in the pabna region of bangladesh provide data to test predictions of a safety first model and of a profit maximisation model of farmer behaviour of the two sets of predictions the data tend to support those of the safety first model more frequently than they support the predictions of the profit maximisation model while the degree to which the former model out performs the latter is not great it is important to note that when the major inputs land and human labour and the major outputs rice and jute are focused upon the safety first model performs much better than the profit maximisation model

risk constrained self scheduling of hydro wind units for short term electricity markets considering intermittency and uncertainty abstract in view of the intermittency and uncertainty associated with both the electricity production sector of restructured power system and their competitive markets it is necessary to develop an appropriate risk managing scheme so that it is desirable to trade off between optimum utilization of intermittent generation resources i e renewable energy resources uncertain market prices and related risks in order to maximize participants benefits and minimize the corresponding risks in the multi product market environment the main goal of this paper is to investigate risk management by introducing a novel multi risk index to quantify expected downside risk edr which is caused by both the wind power and market price uncertainties value at risk var method is used to assess the mentioned risk issue by the proposed weighted edr so that an optimal trade off between the profit and risk is made for the system operations also the roulette wheel mechanism is employed for random market price scenario generation wherein the stochastic procedure is converted into its respective deterministic equivalents moreover the autoregressive integrated moving average arima model is employed to characterize the stochastic wind farm wf generation by predetermined mean level and standard deviation of wind behavior as well as temporal correlation the problem is formulated as a mixed integer stochastic framework for a hydro wind power system scheduling and tested on a generation company genco

grain substitution and food dependency in the third world abstract critics of the green revolution in agriculture have argued that the introduction of high yielding varieties of seed and their requisite complementary inputs to the countries of the third world have actually rendered these countries more food dependent than before it is also argued that the internal results of this technology transfer have been increasing inequality in the distribution of income and growing malnutrition of the majority of the populations in these countries the purpose of this paper is to examine empirically the relationships between so called grain substitution and several indicators of human welfare including malnutrition and child mortality the study is based on cross country data covering over 70 nations in the third world and a time period extending from the early to mid 1960s through 1989 1990 the results suggest a negative and statistically significant relationship between social welfare and the process of grain substitution on the other hand the data do not support the proposition that grain substitution is significantly related to levels of external food dependency

contract farming and smallholder outgrower schemes in less developed countries abstract some studies of outgrower schemes involving smallholders and public or private corporations in less developed countries suggest the potential value of such arrangements in facilitating transfer of technology access to markets and other benefits for growers a diverse literature is surveyed to see what economic and political questions have been raised which have a bearing on the issue of grower welfare in some cases existing literature or the author s own research provides adequate answers to the questions raised in others the need for further research is indicated some possible directions and methodologies for systematic comparative studies are suggested

optimal portfolio selection under institutional procedures for short selling abstract this study presents and formally justifies a simple ranking approach for optimal portfolio selection under institutional procedures for short selling it also provides economic insights of the explicit solution of the portfolio problem the analysis is applicable to different treatments of the short sale proceeds and any margin deposits in contrast to previous approaches it does not require assumptions that overstate short sale benefits for maintaining analytical tractability and it can easily identify and filter out securities that are undesirable for investing or for short selling thus this study can enhance the usefulness of portfolio modeling for assisting practical investment decisions

determinants of levered portfolio performance the cumulative return to a levered strategy is determined by five elements that fit together in a simple and useful formula a previously undocumented element is the covariance between leverage and excess return to the fully invested source portfolio underlying the strategy in an empirical study of volatility targeting strategies over the 84 year period 1929 2013 this covariance accounted for a reduction in return that substantially diminished the sharpe ratio in all cases

weather shocks and agricultural commercialization in colonial tropical africa did cash crops alleviate social distress a rapidly growing body of research examines the ways in which climatic variability influences economic and societal outcomes this study investigates how weather shocks triggered social distress in british colonial africa further it intervenes in a long standing and unsettled debate concerning the effects of agricultural commercialization on the abilities of rural communities to cope with exogenous shocks we collect qualitative evidence from annual administrative records to explore the mechanisms linking weather extremes to harvest failures and social distress we also conduct econometric testing on a novel panel dataset of 143 administrative districts across west south central and east africa in the interwar era 1920 39 our findings are twofold first we find robust evidence that rainfall anomalies both drought and excessive precipitation are associated with spikes in imprisonment our proxy for social distress we argue that the key causal pathway is the loss of agricultural income which results in higher imprisonment for theft unrest debt and tax default second we find that the impact of weather shocks on distress is partially mitigated by the cultivation of export crops our findings suggest that even in the british colonial context smallholder export crop cultivation led to higher private incomes as well as greater public investment our findings speak to a topic of considerable urgency today as the process of global climate change accelerates generating more severe and unpredictable climatic extremes an increased understanding and identification of adaptive and mitigating factors would assist in targeting policy interventions and designing adaptive institutions to support vulnerable rural societies

market efficiency a theoretical distinction and so what with the aid of some simplifying assumptions the capital asset pricing model comes to dramatic conclusions about practical matters such as how to choose an investment portfolio and how to value financial assets as illustrated in this article when one particular clearly unrealistic capm assumption is replaced by a more real world version some of the dramatic practical conclusions of capm no longer follow this result has implications for financial practice research and pedagogy

modernizing peasant agriculture lessons from el palmar colombia abstract this paper examines the short run and anticipated long run output and income results of the modernization of production in a colombian peasant community el palmar the study finds that in the short run there were increases in output and in producer income as well as increases in local employment and trade opportunities which benefited land poor households however the incidence of extreme poverty in the community was still high after 10 years of modernization the gains from modernization had been limited by the failure of the projects to achieve stable low risk increases in the productivity of peasant resources and many producers had pulled back from adoption of full technological packages in favor of selective and limited adoption the lessons from the community of el palmar are applied to an assessment of the peasant modernization program of the colombian government where it is shown that the problems encountered in el palmar are reflective of problems with the colombian modernization strategy in general the conclusion drawn is that the income gains that can be achieved from the modernization of peasant production in the context of peasant land scarcity and the poor market conditions for traditional peasant products are limited

portfolio optimization with factors scenarios and realistic short positions this paper presents fast algorithms for calculating mean variance efficient frontiers when the investor can sell securities short as well as buy long and when a factor and or scenario model of covariance is assumed currently fast algorithms for factor scenario or mixed factor and scenario models exist but except for a special case of the results reported here apply only to portfolios of long positions factor and scenario models are used widely in applied portfolio analysis and short sales have been used increasingly as part of large institutional portfolios generally the critical line algorithm cla traces out mean variance efficient sets when the investor s choice is subject to any system of linear equality or inequality constraints versions of cla that take advantage of factor and or scenario models of covariance gain speed by greatly simplifying the equations for segments of the efficient set these same algorithms can be used unchanged for the long short portfolio selection problem provided a certain condition on the constraint set holds this condition usually holds in practice

integrated risk management for an electricity producer abstract electricity suppliers face two sources of risk uncertainty of spot prices and uncertainty of production costs uncertainty in selling the output is usually solved by signing forwards and the two sources of risk are dealt with separately however managing the integrated risk optimally is the direction we will suggest we intend to analyse the problem a power producer is confronted to upon acting in a market where spot and forward agreements are available since forwards allow to sell production in advance at a given price but do not hedge against cost volatility the total risk can be reduced by selling also in the spot market the analysis is further detailed to encompass the spread option inherent in electricity production we find a benchmark value for forwards to sign and the optimal spot forward combinations the analysis is carried out by accounting for market figures for input and output variables in the german market eex

the danger of assuming homogeneous expectations the capital asset pricing model the black scholes option valuation model and many other economic models rely on the assumption of homogeneous expectations what are the effects of heterogeneous expectations on price determination are the homogeneous expectations models approximately correct we compare stock price dynamics in models with homogeneous and heterogeneous expectations heterogeneous expectations appear to play a crucial role in risky asset price determination when homogeneous expectations are assumed unacceptable market inefficiencies are observed the introduction of even a small degree of diversity of expectations changes the dynamics dramatically and the result is a much more realistic market these findings make one wonder how far the equilibrium prices of the capm and black scholes model are from the true values in markets with heterogeneous expectations

financial risk reduction in photovoltaic projects through ocean atmospheric oscillations modeling abstract the impact of climate change on society has increased the interest to deploy renewable energies and to understand climate climate variability is partly predictable and is a fundamental factor in explaining financial risk in renewable energy projects current methodologies used for risk assessment do not appropriately account for climate predictability we found limited literature on risk reduction on pv projects through the modeling of predictable components of solar radiation and ocean atmospheric oscillations allowing us to present original proposals to fill these voids a new profit model for pv plants was developed capturing this predictable climate information the proposed methodology is potentially applicable to hydro wind and other renewable resources and allows leaving aside predictable climate components from the project s risk calculation the model was tailored for the risk assessment of pv investments and is applied over 10 geographical areas across chile the largest pv market in latin america where climate is strongly affected by 3 ocean atmospheric oscillations el nino southern oscillation southern annular mode and indian ocean dipole using the model in these regions allows reducing the monthly financial the risk to reduce by 60 81 compared to traditional methodology for a 100 mw pv project located in those areas this means reducing annualized risk from 4 93 to 7 88 mm usd year traditional model to 1 11 2 38 mm usd year proposed model modeling of ocean atmospheric oscillations allows achieving the greatest risk reduction between the cities of copiapo and coquimbo north central regions decreasing their influence towards the extreme latitudes their risk reduction will depend on the quality of the model and may have strong implications for both investors and financial institutions it could also impact competition in the energy sector due to possible asymmetries of information to facilitate extending the use of the model elsewhere the incorporation of subsidies is discussed

stochastic security constrained unit commitment this paper presents a stochastic model for the long term solution of security constrained unit commitment scuc the proposed approach could be used by vertically integrated utilities as well as the isos in electricity markets in this model random disturbances such as outages of generation units and transmission lines as well as load forecasting inaccuracies are modeled as scenario trees using the monte carlo simulation method for dual optimization coupling constraints among scenarios are relaxed and the optimization problem is decomposed into deterministic long term scuc subproblems for each deterministic long term scuc resource constraints represent fuel and emission constraints in the case of vertically integrated utilities and energy constraints in the case of electricity markets lagrangian relaxation is used to decompose subproblems with long term scuc into tractable short term mip based scuc subproblems without resource constraints accordingly penalty prices lagrangian multipliers are signals to coordinate the master problem and small scale subproblems computational requirements for solving scenario based optimization models depend on the number of scenarios in which the objective is to minimize the weighted average generation cost over the entire scenario tree in large scale applications the scenario reduction method is introduced for enhancing a tradeoff between calculation speed and accuracy of long term scuc solution numerical simulations indicate the effectiveness of the proposed approach for solving the stochastic security constrained unit commitment

the capital asset pricing model in economic perspective the capital asset pricing model capm is theoretically incomplete in its demand side focus risk averse investors and internally inconsistent homogeneous beliefs is not conclusively supported empirically and yet it legitimizes a notion that investors can earn higher returns by bearing undiversifiable risk our article does not merely extend the capm with more realistic assumptions it completes its original framework by including 1 risk taking investors in the investor population 2 investors who can have heterogeneous expectations or beliefs an overlooked but required condition for the capm to be an internally consistent and meaningful model of competitive financial asset pricing under uncertainty and 3 a positive sloped short run supply curve based on a reasonable interpretation of the nature of financial asset trade upon a complete economic interpretation it is shown that the equilibrium systematic risk rate of return relationship depends on whose aggregate trading activity dominates ri

agro export production and peasant land access examining the dynamic between adoption and accumulation abstract new technologies and export opportunities have often contributed to dualistic agrarian structure and intense social conflict in latin american a switching regression model developed in this paper explicitly links export adoption and land accumulation patterns controlling for pre existing differentiation processes applied to survey data gathered from peasant households in guatemala the model provides evidence of equitable structural change induced by a recent export boom in vegetable crops however the optimism of these results is tempered by consideration of the unfavorable longer term market dynamics confronting small scale producers

communal property and land markets agricultural development policy in st lucia abstract communal land tenure in st lucia was targeted for privatization in 1986 on the premise that its undercapitalization and low productivity could be corrected by establishing an efficient land market this article takes the neoclassical analysis which was used to support this policy to task with empirical evidence from st lucia it argues that the inefficiencies attributed to communal land only are not justified many of these inefficiencies are in fact also shared with freehold tenure in addition family land performs socioeconomic functions that cannot be achieved with freehold tenure and fulfills a critical function in the development process

environment development and politics capital accumulation and the livestock sector in eastern amazonia summary deforestation and environmental degradation are increasingly common themes in the literature on humid tropical rural development this paper explores the frameworks used to analyze environmental questions in developing economies and how well these function in the particular case of livestock development in the eastern amazon basin the paper argues that due to the peculiarities of the state subsidies available for ranching activities that spurred a frenzy of land speculation the exchange rather than productive value of land became paramount in such a context cautious land management was irrelevant and serious environmental degradation was the result the paper suggests that models of environmental degradation that focus only on the question of production cannot capture the environmental dynamics of speculative economies

trimability and fast optimization of long short portfolios optimization of long short portfolios through the use of fast algorithms takes advantage of models of covariance to simplify the equations that determine optimality fast algorithms exist for widely applied factor and scenario analysis for long only portfolios to allow their use in factor and scenario analysis for long short portfolios the concept of trimability is introduced the conclusion is that the same fast algorithms that were designed for long only portfolios can be used virtually unchanged for long short portfolio optimization provided the portfolio is trimable which usually holds in practice

short selling and efficient sets the effect of short selling on the composition and location of the efficient set has been analyzed in a variety of ways however the situation typically facing investors where the initial margin requirement is less than 100 percent and the riskfree interest rate that is paid on the short proceeds is less than the rate paid on initial margin has not previously been considered the elton gruber padberg algorithm 1976 1978 subject to certain modifications is shown here to be capable of identifying the efflcient set under such conditions when harry markowitz 1952 developed the notion of efficient sets as a method of identifying an investor s optimal portfolio he did so in a setting where short selling was prohibited since then the effect of short selling on the composition and location of the efficient set has been considered in a variety of ways for example lintner 1965 suggested that short sales be treated from the perspective of a broker dealer where an amount of money equal to the short proceeds must be put up as initial margin with the short seller receiving riskfree interest on both the short proceeds and the margin alternatively black 1972 and merton 1972 assumed that the short seller did not have to put up any initial margin and that the short seller actually got the use of the short proceeds more recently dyl 1975 has assumed that the short seller must put up initial margin that is less than the short proceeds but receives no interest on either the margin or short proceeds this paper is concerned with the generation of efficient sets where short selling is allowed but with certain restrictions attached to it referred to hereafter as restricted short selling in particular initial margin is required but can be met by depositing interest bearing securities with the brokerage firm where the short seller s account is kept furthermore the model allows the short seller to earn interest on the short proceeds accordingly the model

energy landscape in mauritius abstract located in the indian ocean mauritius is among the small island developing states sids entirely reliant on coal petroleum and some locally available renewable energy sources to satisfy energy needs 22 7 of the electricity is generated by biomass solar landfill gas and hydro and the remaining by fossil fuels even with continual oil price volatilities and specific economic social and environmental vulnerabilities compared to continental areas mauritius has successfully provided 100 electricity to all its residents however with a growth in population and economy mauritius faces a crucial challenge to supply more electrical power to all requiring sectors renewable energy appears to be the most effective solution to cater for the increase in electricity demand but there are still huge challenges to overcome for massive deployment of more renewable energy in this context this paper reviews the current electricity industry and fuel sources for electricity production in mauritius it also describes future energy policies for more renewable energy integration within the energy mix by 2025

structural change in malawi since independence consequences of a development strategy based on large scale agriculture abstract this paper investigates the nature of the structural change which has occured in the malawian economy since independence and identifies key policies pursued by the government which it is argued have been decisive in shaping this development the salient feature of structural change is shown to be the rapid growth of large scale agriculture associated with an equally rapid transfer of labour into wage employment and a decline in the importance of peasant production the implications of these changes for living standards and future development and policy are considered

climate change mitigation and agricultural development models primary commodity exports or local consumption production abstract the increasing demand for agricultural products partly due to the high population growth requires agriculture to struggle for productivity improvement however productivity search is constrained by environmental preoccupations raising the question of agricultural development models to be adopted to increase productivity while limiting environmental consequences this paper examines the role of market orientation by assessing the effect of agricultural commodity export on greenhouse gas emissions relatively to local market oriented agricultural production model using panel data from 1986 to 2010 for 136 countries around the world and accurate instrumental variables technique the findings suggest that the proportion of primary commodity export in agricultural production increases greenhouse gas emissions these results are robust to different sources of agricultural export and environmental data and to the inclusion of additional control variables

the long run determinants of north south terms of trade and some recent empirical evidence abstract this paper reviews some recent evidence of the long run decline in the terms of trade of primary commodities versus manufactures in the context of north south trade this evidence is evaluated in the light of competing explanations of the sources of the observed long run trends in the context of a model of north south trade which includes a general resource labor and capital in the north and specific factors in a dual economy model of the south changes in factor supply sectoral and factoral bias in technical change biased demand conditions changes in the pattern of protection and institutional elements all play a role in determining the evolution of commodity and factor prices the lewis hypothesis of sectoral bias in the pattern of technical change towards temperate agriculture in the north and against tropical agriculture in the south is then reexamined in the light of the recent empirical evidence on terms of trade movements and some sketchy evidence presented on the patterns of bias in technical change in the north and the south the evidence is not consistent with an absolute technical change bias towards temperate agriculture in the north rather the rate of technical change in temperate agriculture is now comparable to that experienced in manufactures so that engel curve effects now assert the major downward pressure on the long run terms of trade between temperate agriculture commodities and manufactures overriding the effects of diminishing returns to natural resources as northern population expands the empirical evidence onbiased technical change in the south is much more sketchy and the evidence on various components of north south terms of trade is more varied

strategic trading behavior and price distortion in a manipulated market anatomy of a squeeze abstract this paper investigates an attempted delivery squeeze in a bond futures contract traded in london using cash and futures trades of dealers and customers we analyze their strategic trading behavior price distortion and learning in a market manipulation setting we argue that marked differences in settlement failure penalties in the cash and futures markets create conditions that favor squeezes we recommend that regulators require special flagging of forward term repurchase agreements on the key deliverables that span futures contract maturity dates and that exchanges mark to market their contract specifications more frequently or consider a cash settled contract on a basket of bonds

impossible frontiers a key result of the capital asset pricing model capm is that the market portfolio the portfolio of all assets in which each asset s weight is proportional to its total market capitalization lies on the mean variance efficient frontier the set of portfolios having mean variance characteristics that cannot be improved upon therefore the capm cannot be consistent with efficient frontiers for which every frontier portfolio has at least one negative weight or short position we call such efficient frontiers impossible and show that impossible frontiers are difficult to avoid in particular as the number of assets n grows we prove that the probability that a generically chosen frontier is impossible tends to one at a geometric rate in fact for one natural class of distributions nearly one eighth of all assets on a frontier is expected to have negative weights for every portfolio on the frontier we also show that the expected minimum amount of short selling across frontier portfolios grows linearly with n and even when short sales are constrained to some finite level an impossible frontier remains impossible using daily and monthly u s stock returns we document the impossibility of efficient frontiers in the data

recent advances in electricity price forecasting a review of probabilistic forecasting abstract since the inception of competitive power markets two decades ago electricity price forecasting epf has gradually become a fundamental process for energy companies decision making mechanisms over the years the bulk of research has concerned point predictions however the recent introduction of smart grids and renewable integration requirements has had the effect of increasing the uncertainty of future supply demand and prices academics and practitioners alike have come to understand that probabilistic electricity price and load forecasting is now more important for energy systems planning and operations than ever before with this paper we offer a tutorial review of probabilistic epf and present much needed guidelines for the rigorous use of methods measures and tests in line with the paradigm of maximizing sharpness subject to reliability the paper can be treated as an update and a further extension of the otherwise comprehensive epf review of weron 1 or as a standalone treatment of a fascinating and underdeveloped topic that has a much broader reach than epf itself

multivariate dependence and portfolio optimization algorithms under illiquid market scenarios we propose a model for optimizing structured portfolios with liquidity adjusted value at risk lvar constraints whereby linear correlations between assets are replaced by the multivariate nonlinear dependence structure based on dynamic conditional correlation t copula modeling our portfolio optimization algorithm minimizes the lvar function under adverse market circumstances and multiple operational and financial constraints when we consider a diversified portfolio of international stock and commodity market indices under multiple realistic portfolio optimization scenarios the obtained results consistently show the superiority of our approach relative to other competing portfolio strategies including the minimum variance risk parity and equally weighted portfolio allocations

a global stock and bond model six fundamental risk factors four for stocks and two for bonds explain most of the common volatility of individual stocks and bonds worldwide some of the risk factors have a strong international component and others are more purely national the cross national component of the risk factors tends to be stronger within the european union than worldwide the model proposed in this article can be used for integration of worldwide asset selection and asset allocation decisions

increasing the benefits to smallholders from contract farming problems for farmers organizations and policy makers abstract contract farming cf is potentially beneficial to small farmers providing services not readily available by other means in reality growers frequently face serious problems in dealing with firms indicating the need for intervention by government or by farmers organizations however the hybrid structure and multiple objectives of cf schemes make it difficult to organize farmers or to design effective policy interventions this article describes some of the most frequent problems points out trade offs among competing welfare goals and cautions against the use of cf as a simple model for agricultural development

interdependence between cash crop and staple food international prices across periods of varying financial market stress abstractthis paper investigates the price dynamics between a selection of international staple food and cash crop futures prices this price interaction is particularly relevant for developing coun

risk constrained profit maximization in day ahead electricity market the deregulation of the electricity industry has caused for the generation company genco the need of tools for measuring and managing the risk beyond the classical problem of generating unit scheduling in this paper a probabilistic framework for the problem of managing risk faced by gencos trading in day ahead energy market is proposed in particular a stochastic forecast of electricity price and the technical features of hydrothermal units are considered the approach is based on an optimization procedure for maximizing expected profits in the presence of risk constraints conditional value at risk for the distribution of daily profit is used as risk measure

the currency hedging decision a search for synthesis in asset allocation many asset allocation and liability management decisions are controversial but the decision that frequently generates the most debate is the currency hedging decision strong feelings on currency exposure policy are usually based on the conviction that currency exposures should be determined by a simple mechanical process but not everyone advocates the same process a survey of the leading proposals to simplify the currency management process suggests that a baseline currency policy may lend itself to some mechanical rules but the rules are more complex than any of the widely advocated currency hedging policies suggest equity and fixed income managers as well as asset allocators will find currency issues easier to understand if they view currencies as they would view any other financial instrument the importance of currency management is clearer if a manager and client start from a 50 50 hedged unhedged currency benchmark and if currency and money market returns are combined the combination of currency and money market returns strips primary currency movements from stock and bond returns clarifying intermarket correlations and creating synthetic stock and bond futures portfolios no one can harbor illusions that this study or any similar effort can completely eliminate currency hedging controversies the argument has gone on too long and too many positions are ossified nonetheless most practitioners can understand the strengths and weaknesses of the various currency hedging viewpoints and the assumptions behind them can be evaluated dispassionately this dispassionate evaluation leads to a baseline currency policy but not to a rigid prescription for currency hedging designed to satisfy the demand for a simple rule the policy suggests an approach that can help a manager measure the cost or risk of a specific currency com

how does the diversity of investors beliefs affect stock price informativeness abstracta growing number of studies have investigated the role of stock prices in aggregating private information and guiding resource reallocation however this article may be the first attempt to study how the diversity of beliefs affects stock price informativeness the framework of the noisy rational expectations model shows that stock informativeness is determined by both the precision and use of private information in trading if private beliefs about the value are highly diverse the aggregate average opinion revealed in a stock s price will be more accurate and thus more informative as the price becomes more informative however individual investors will rely less on their private information when this occurs less private information will be absorbed in price which in turn reduces price informativeness our model shows that the relationship between belief diversity and price informativeness is u shaped in equilibrium

farm to market transaction costs and specialisation in small scale agriculture explorations with a non separable household model using an integrated household model with endogenous transaction costs this article illustrates how even in the absence of risk the tension between gains from specialisation and corresponding increases in transaction costs may lead to enterprise diversification on small farms a numerical example illustrates that this tension may contribute to the prevalence of inter cropped cash crops on small farms in apparent disregard for foregone yield and income from greater specialisation involving pure stands by implication measures that augment households abilities to override trading costs may be critical complements to efforts seeking to raise productivity and incomes in small scale agriculture via increased specialisation

will my risk parity strategy outperform the authors gauged the return generating potential of four investment strategies value weighted 60 40 fixed mix and unlevered and levered risk parity they report three main findings 1 even over periods lasting decades the start and end dates of a backtest can have a material effect on results 2 transaction costs can reverse ranking especially if leverage is used and 3 a statistically significant return premium does not guarantee outperformance over reasonable investment horizons see comments and response on this article

on the optimality of long short strategies we consider the optimality of portfolios not subject to short selling constraints and derive conditions that a universe of securities must satisfy for an optimal active portfolio to be dollar neutr

heterogeneity of commercialization gains in the rural economy farmers in low income rural economies often fail to switch to cash crops from staple production despite the positive income effects of commercialization expected by policy makers the literature suggests that market failures prevent households from cash crop adoption but remains inconclusive regarding farmers motives and the effects of commercialization this article contributes to the debate by offering an original approach to the analysis of commercialization outcomes and farmers decisions it consists of applying a model with essential heterogeneity and a semiparametric estimation technique to analyzing harvest value returns to cash cropping using malawian data we show considerable heterogeneity in harvest value returns to cash cropping both within and between groups of farmers choosing different crop portfolios importantly the results imply rational choices based on comparative advantage considerations of farming households farmers self select into the activity where they expect higher gains and adopt cash crops when facing weaker market barriers

national versus global influences on equity returns simple factor models of worldwide equity returns are used to explore the level and trend in international capital market integration global influences and national influences are of roughly equal importance in explaining the common movements in equity returns significant evidence indicates a trend toward increasing integration within the european union but not worldwide

relative agricultural prices and the urban bias model a comparative analysis of tanzania and fiji the paper critically examines agricultural price aspects of the urban bias model especially the links between class interests government policies and the trend of real agricultural prices the paper contains an analysis of the principal factors both economic and political underlying agriculture s terms of trade in two contrasting countries tanzania and fiji both case studies in different ways raise doubts about the generality of urban bias propositions as they relate to agricultural prices they also suggest important weaknesses in the model s interpretation of the politics of farm prices

financial risk evaluation in stochastic pbuc this letter is an extension of our previous price based unit commitment pbuc work this letter identifies a frontier relationship between payoff and risk this letter also discusses the calculation of target value and risk using payoff risk frontiers test results show a trade off between risk minimization and payoff maximization for power generation utilities

sustainability in the diffusion of innovations smallholder nontraditional agro exports in guatemala i nontraditional agro exports in guatemala since the late 1970s guatemala like a number of other developing countries has experienced an extraordinarily rapid growth in the production of nontraditional agro exports ntxs the share of agricultural exports coming from ntxs grew from less than 6 in 1980 to more than 22 in 1992 rationales behind the promotion of ntxs by governments and development agencies include seeking foreign exchange earnings alternatives to depressed market conditions for traditional export crops and rural poverty reduction as part of the packages mandated by structural adjustment and trade liberalization programs many national governments including guatemala s introduced policies in favor of ntx producers such as export facilitation procedures subsidy programs and fiscal reforms trade agreements such as the generalized system of preferences and the caribbean basin initiative created additional incentives for ntx exporters in the guatemalan context private organizations and trade associations such as the association of exporters of nontraditional products played a catalytic role in promoting ntxs in the 1980s as a potential new approach to rural development international donors have invested heavily in the promotion of ntxs among smallholders one such effort that received considerable attention is the agricultural cooperative cuatro pinos that was founded in 1979 with financial assistance from a swiss development agency cooperative membership grew tenfold in the following 10 years reaching more than 1 900 members in the late 1980s and operating in ten different villages pre ntx agriculture in the region was dominated by the milpa sys

modeling approaches for computational cost reduction in stochastic unit commitment formulations although stochastic commitment policies provide robust and efficient solutions they have high computational costs this letter considers two modeling approaches for the reduction of their computational effort the relaxation of the integrality constraint of fast start units and the modeling of generation outages as load increments these approaches are shown to reduce the computational cost while maintaining the good properties of stochastic policies

level playing fields and laissez faire postliberal development strategy in inegalitarian agrarian economies focusing on the rural sector in latin america this paper explores the microeconomic linkages between distribution and growth which drive the possible reproduction of rural poverty over time the result of this exploration is a neostructuralist perspective which argues that actually existing laissez faire agrarian economies do not present a level playing field and that low wealth farms face disadvantages which tend to reproduce or even deepen sectoral inequality the paper then tries to identify the sorts of public policy and collective action which might modify the nature of growth and distribution in post liberalization agrarian market economy

stochastic multiobjective market clearing of joint energy and reserves auctions ensuring power system security in this paper a stochastic multiobjective framework is proposed for day ahead joint market clearing the proposed multiobjective framework can concurrently optimize competing objective functions including augmented generation offer cost and security indices overload index voltage drop index and voltage stability margin besides system uncertainties including generating units and branches contingencies and load uncertainty are explicitly considered in the stochastic market clearing scheme the solution methodology consists of two stages which firstly employs roulette wheel mechanism and monte carlo simulation mcs for random adaptive 24 h scenario generation wherein the stochastic multiobjective market clearing procedure is converted into its respective deterministic equivalents scenarios in the second stage for each deterministic scenario a multiobjective mathematical programming mmp formulation based on the epsiv constrained approach is implemented for provision of spinning reserve sr and nonspinning reserve nsr as well as energy the mmp formulation of the market clearing process is optimized while meeting ac power flow constraints and expected interruption cost eic the ieee 24 bus reliability test system rts 24 bus is used to demonstrate the performance of the proposed method

simulating security markets in dynamic and equilibrium modes an asynchronous discrete time model run in dynamic mode can model the effects on market prices of changes in strategies leverage and regulations or the effects of different return estimation procedures and different trading rules run in equilibrium mode it can be used to arrive at equilibrium expected returns

shifts from maize to sorghum production nutrition effects in four mexican communities abstract this paper examines how commercialization of agriculture especially the production of sorghum as a cash crop has affected household economic strategies and child nutritional status in four agrarian reform communities in mexico growing sorghum as a cash crop over maize as a semi subsistence crop has not placed the families of these small farmers in nutritional jeopardy nor has it provided them with a significantly better situation access to basic productive resources especially good quality land wage labour opportunities ecological conditions and agrarian and agricultural policy are more important than crop choice in determining the welfare of rural populations

the three types of factor models a comparison of their explanatory power multifactor models of security market returns can be divided into three types macroeconomic fundamental and statistical factor models macroeconomic factor models use observable economic time series such as inflation and interest rates as measures of the pervasive shocks to security returns fundamental factor models use the returns to portfolios associated with observed security attributes such as dividend yield the book to market ratio and industry identifiers statistical factor models derive their pervasive factors from factor analysis of the panel data set of security returns this paper compares the explanatory power of these three approaches for u s equity returns

a policymaker s guide to comparative advantage abstract for a country to produce according to its comparative advantage simply means that it chooses to produce those things which it can produce best such choice may be implemented by market mechanisms or by administrative means since most production decisions commit a country for more than a single period the future is relevant to present comparative advantage however the future is shaped in part by the actions of the present rather than being entirely exogenous the past also affects present comparative advantage through the legacy of installed productive capacity the dynamic domestic resource cost of foreign exchange is a quantitative tool which can be useful in the qualification and implementation of a comparative advantage oriented policy

inequality in sub saharan africa new data and new insights from anthropometric estimates reliable information on inequality within countries is highly scarce especially for less developed countries ldcs using anthropometric measures we extend the inequality database for sub saharan africa to no less than 28 countries over six five year periods from 1950 to 1980 and to some 200 regions within those countries in this process we also test in depth the validity of objections against the derivation of inequality measures from height data in a second step we test the determinants of inequality within and between the 200 regions under study our set of explanatory variables includes protein supply cash cropping industrial structure mineral resources distance to the countries capital urbanization education population density and ethnic fractionalization we find that monoculture cash cropping increases inequality whereas diversified cash cropping has the opposite effect

cleaning house new perspectives on households and economic development abstract this paper provides a critical review of the recent literature on households and economic development three related points are developed 1 household activities can be analyzed in economic terms particularly if these terms are broadly defined to encompass such factors as risk and uncertainty 2 significant differences between the economic position of men women and children within the patriarchal household mean that it cannot be treated as an undifferentiated unit of analysis 3 microeconomic analysis of the household must be situated within a larger structural analysis of gender and age based inequalities and their interaction with class structure and national position within the world capitalist system

a review of the wind power developments in pakistan abstract pakistan is among the 10 countries that face the worst energy crisis of the world as the country struggles with a number of financial political and social issues the transition from a conventional fuels based economy to a green economy is not an easy one pakistan has been blessed with immense potential of clean renewable sources of solar wind and biomass but they have not been exploited yet renewable energy technology sector has not penetrated the energy mix and is currently an emerging market this paper highlights the steps the country has taken in the past and the steps that are being taken at present to emerge out of the prevailing energy crisis when even the most urban areas suffer from power outages of 12 h per day until 2009 no single grid interconnected wind farm existed but now the situation has changed considerably and wind farms contributing to the national grid are a reality now three grid interconnected farms have been inaugurated and many others are in pipeline the national policy regarding wind power systems has recently changed after unexpected setbacks to ongoing projects this paper reviews the developments in the wind power sector of the country and lists some suggestions that can help improve the wind power penetration in the national energy mix

cash crops in developing countries the issues the facts the policies the issue of cash crops is profoundly controversial the debate uses different definitions of the term and slides across levels of analysis from the household to the international economy it also cuts across arguments crops countries and time periods this paper sets out to order the debate it deals first with definitions and taxonomy and then reviews issues connected with cash crops and a growth b distribution c food security d dependency and e the environment the paper concludes that with appropriate policies cash crops can offer a route to equitable growth