a market discovery algorithm to estimate a general class of nonparametric choice models we propose an approach for estimating customer preferences for a set of substitutable products using only sales transactions and product availability data the underlying demand framework combines a general nonparametric discrete choice model with a bernoulli process of arrivals over time the choice model is defined by a discrete probability mass function pmf on a set of possible preference rankings of alternatives and it is compatible with any random utility model an arriving customer is assumed to purchase the available option that ranks highest in her preference list the problem we address is how to jointly estimate the arrival rate and the pmf of the rank based choice model under a maximum likelihood criterion since the potential number of customer types is factorial we propose a market discovery algorithm that starts with a parsimonious set of types and enlarge it by automatically generating new types that increase the likelihood value numerical experiments confirm the potential of our proposal for a realistic data set in the hospitality industry our approach improves the root mean square errors between predicted and observed purchases computed under independent demand model estimates by 67 to 93 this paper was accepted by serguei netessine operations management

estimation of consumer demand with stock out based substitution an application to vending machine products the occurrence of temporary stock outs at retail is common in frequently purchased product categories available empirical evidence suggests that when faced with stock outs consumers are often willing to buy substitute items an important implication of this consumer behavior is that observed sales of an item no longer provide a good measure of its core demand rate sales of items that stock out are right censored while sales of other items are inflated because of substitutions knowledge of the true demand rates and substitution rates is important for the retailer for a variety of category management decisions such as the ideal assortment to carry how much to stock of each item and how often to replenish the stock the estimated substitution rates can also be used to infer patterns of competition between items in the category in this paper we propose methods to estimate demand rates and substitution rates in such contexts we develop a model of customer arrivals and choice between goods that explicitly allows for possible product substitution and lost sales when a customer faces a stock out the model is developed in the context of retail vending an industry that accounts for a sizable part of the retail sales of many consumer products we consider the information set available from two kinds of inventory tracking systems in the best case scenario of a perpetual inventory system in which times of stock out occurrence and cumulative sales of all goods up to these times are observed we derive maximum likelihood estimates mles of the demand parameters and show that they are especially simple and intuitive however state of the art inventory systems in retail vend ing provide only periodic data i e data in which times of stock out occurrence are unobserved or missing for these data we show how the expectation maximization em algorithm can be employed to obtain the mles of the demand parameters by treating the stock out times as missing data we show an application of the model to daily sales and stocking data pooled across multiple beverage vending machines in a midwestern u s city the vending machines in the application carry identical assortments of six brands since the number of parameters to be estimated is too large given the available data we discuss possible restrictions of the consumer choice model to accomplish the estimation our results indicate that demand rates estimated naively by using observed sales rates are biased even for items that have very few occurrences of stock outs we also find significant differences among the substitution rates of the six brands the methods proposed in our paper can be modified to apply to many nonvending retail settings in which consumer choices are observed not their preferences and choices are constrained because of unavailability of items in the choice set one such context is in store grocery retailing where similar issues of information availability arise in this context an important issue that would need to be dealt with is changes in the retail environment caused by retail promotions

sulfur dioxide control by electric utilities what are the gains from trade title iv of the 1990 clean air act amendments caaa established a market for transferable sulfur dioxide so2 emission allowances among electric utilities this market offers firms facing high marginal abatement costs the opportunity to purchase the right to emit so2 from firms with lower costs and this is expected to yield cost savings compared to a command and control approach to environmental regulation this paper uses econometrically estimated marginal abatement cost functions for power plants affected by title iv of the caaa to evaluate the performance of the so2 allowance market specifically we investigate whether the much heralded fall in the cost of abating so2 compared to original estimates can be attributed to allowance trading we demonstrate that for plants that use low sulfur coal to reduce so2 emissions technical change and the fall in prices of low sulfur coal have lowered marginal abatement cost curves by over 50 percent since 1985 the flexibility to take advantage of these chan

recent advances in the valuation of ecosystem services and biodiversity recent interest in the economics of biodiversity and wider ecosystem services has been given empirical expression through a focus upon economic valuation this emphasis has been prompted by a growing recognition that the benefits and opportunity costs associated with such services are frequently given cursory consideration in policy analyses or even completely ignored the valuation of biodiversity and ecosystem services is therefore increasingly seen as a crucial element of robust decision making and this has been reflected in a growing body of related research we provide a critical review of some of this research considering the valuation methods applied to date and focussing upon their limitations in respect to certain categories of ecosystem services particularly cultural services and the applicability of the extant literature to new settings substantial questions also remain at the interface of natural science and economics and we consider the potential contribution of the conceptualization of ecosystems as assets as a response to this challenge as part of this review we also highlight the role which large scale ecosystem assessments have played as an impetus to extending the valuation evidence base and the way in which frameworks and assessments of how ecosystems contribute to human wellbeing might be translated into policy thinking and decision analyses

protecting forests biodiversity and the climate predicting policy impact to improve policy choice p olicies must balance forest conservation s local costs with its benefits local to global in terms of biodiversity the mitigation of climate change and other eco services such as water quality the trade offs with development vary across forest locations we argue that considering location in three ways helps to predict policy impact and improve policy choice i policy impacts vary by location because baseline deforestation varies with characteristics market distances slopes soils etc of loca tions in a landscape ii different mixes of political economic pressures drive the location of different policies and iii policies can trigger second order or spillover effects likely to differ by location we provide empirical evidence that suggests the importance of all three considerations by reviewing high quality evaluations of the impact of conservation and development on forest impacts of well enforced conservation rise with private clearing pressure supporting i protection types e g federal state dif fer in locations and thus in impacts supporting ii differences in development process explain differ ent signs for spillovers supporting iii

a nonparametric approach to modeling choice with limited data choice models today are ubiquitous across a range of applications in operations and marketing real world implementations of many of these models face the formidable stumbling block of simply identifying the right model of choice to use because models of choice are inherently high dimensional objects the typical approach to dealing with this problem is positing a priori a parametric model that one believes adequately captures choice behavior this approach can be substantially suboptimal in scenarios where one cares about using the choice model learned to make fine grained predictions one must contend with the risks of mis specification and overfitting underfitting thus motivated we visit the following problem for a generic model of consumer choice namely distributions over preference lists and a limited amount of data on how consumers actually make decisions such as marginal information about these distributions how may one predict revenues from offering a particular assortment of choices an outcome of our investigation is a nonparametric approach in which the data automatically select the right choice model for revenue predictions the approach is practical using a data set consisting of automobile sales transaction data from a major u s automaker our method demonstrates a 20 improvement in prediction accuracy over state of the art benchmark models this improvement can translate into a 10 increase in revenues from optimizing the offer set we also address a number of theoretical issues among them a qualitative examination of the choice models implicitly learned by the approach we believe that this paper takes a step toward automating the crucial task of choice model selection this paper was accepted by yossi aviv operations management

confronting the environmental kuznets curve t he environmental kuznets curve posits an inverted u relationship between pollution and economic development kuznets s name was apparently attached to the curve by grossman and krueger 1993 who noted its resemblance to kuznets s inverted u relationship between income inequality and development in the first stage of industrialization pollution in the environmental kuznets curve world grows rapidly because people are more interested in jobs and income than clean air and water communities are too poor to pay for abatement and environmental regulation is correspondingly weak the balance shifts as income rises leading industrial sectors become cleaner people value the environment more highly and regulatory institutions become more effective along the curve pollution levels off in the middle income range and then falls toward pre industrial levels in wealthy societies the environmental kuznets curve model has elicited conflicting reactions from researchers and policymakers applied econometricians have generally accepted the basic tenets of the model and focused on measuring its parameters their regressions typically fitted to cross sectional observations across countries or regions suggest that air and water pollution increase with development until per capita income reaches a range of 5000 to 8000 when income rises beyond that level pollution starts to decline as shown in the conventional ekc line in figure 1 in developing countries some policymakers have interpreted such results as conveying a message about priorities grow first then clean up numerous critics have challenged the conventional environmental kuznets curve both as a representation of what actually happens in the development process and as a policy prescription some pessimistic critics argue that crosssectional evidence for the environmental kuznets curve is nothing more than a

who cares about biodiversity optimal conservation and transboundary biodiversity externalities the convention on biological diversity s 2010 target to reduce the rate of biodiversity loss was achieved by very few countries why we use the theory of conservation implicit in the hotelling model of non renewable resource pricing to analyze the problem distinguishing between the benefits to countries where conservation takes place and to other countries we estimate models for three taxonomic groups and find that while individual countries value conservation within their borders in poor countries this effect is dominated by the negative impact of income growth international concessional financial contributions to conservation in poor countries are found to be statistically insignificant we conclude that countries care about the biodiversity within their national borders but only when development priorities permit and only when it becomes scarce enough that its value grows more rapidly than the return on alternative assets there is little evidence that high income countries yet care sufficiently about biodiversity in the places where it is most threatened to affect conservation outcomes there

evaluation of biodiversity policy instruments what works and what doesn t w e review and confirm the claim that credible evaluations of common conservation instru ments continue to be rare the limited set of rigorous studies suggests that protected areas cause modest reductions in deforestation however the evidence base for payments for ecosystem services decentralization policies and other interventions is much weaker thus we renew our urgent call for more evaluations from many more biodiversity relevant locations specifically we call for a programme of research conservation evaluation 2 0 that seeks to measure how programme impacts vary by socio political and bio physical context to track economic and environmental impacts jointly to iden tify spatial spillover effects to untargeted areas and to use theories of change to characterize causal mechanisms that can guide the collection of data and the interpretation of results only then can we usefully contribute to the debate over how to protect biodiversity in developing countries

valuing research leads bioprospecting and the conservation of genetic resources bioprospecting has been touted as a source of finance for biodiversity conservation recent work has suggested that the bioprospecting value of the marginal unit of genetic resources is likely to be vanishingly small creating essentially no conservation incentive this result is shown to flow specifically from a stylized description of the research process as one of brute force testing unaided by an organizing scientific framework scientific models channel research effort toward leads for which the expected productivity of discoveries is highest leads of unusual promise then command information rents associated with their role in reducing the costs of search when genetic materials are abundant information rents are virtually unaffected by increases in the profitability of product discovery and decline as technology improvements lower search costs numerical simulation results suggest that under plausible conditions the bioprospecting value of certain genetic resources could be large enough to s

dynamite in the ekc tunnel inconsistencies in resource stock analysis under the environmental kuznets curve hypothesis recent studies incorporating consumption into the relationship between gdp and conservation increasingly reveal that economic prosperity does not lead to improvements in environmental quality even in cases where rich countries may appear to protect a greater proportion of their domestic resources this study reinforces those findings for forest and species conservation across two groups of countries additionally through explicit comparison with two previous ekc studies i enable an illustration of precisely how ekc results are affected by the incorporation of consumption and highlight persistent problems with ekc analyses despite general linear modeling results showing that wealthy countries drive deforestation in poorer countries through the import of forest resources ekc analyses can still indicate improvements in conservation for wealthier countries such contradictions suggest that recent methodological improvements to the ekc cannot guarantee the validity of evidence from ekc analyses poor quality of resource stocks data the restrictive time scales that can be examined with those data and the lack of consistent results across different groups of countries all speak to continued inadequacies of the ekc hypothesis and the need to focus on approaches that address actual behavior patterns exhibited by different income groups

cost benefit analysis and mammographic screening a travel cost approach abstract this study describes the methodology and presents preliminary results of an economic appraisal of a program to use mobile mammographic screening units in rural areas of australia the benefits of the project are measured using the travel cost method since mammograms are a binary good conventional welfare analysis must be modified and discrete choice models used to estimate the demand for screening the results suggest that the level of welfare benefits depends on the distance a town is from the nearest fixed screening unit in the 10 towns studied the economic benefits of mobile screening outweighed the economic costs if a rural town is situated 29 km or more from a fixed mammographic screening unit

the censored newsvendor and the optimal acquisition of information this paper investigates the effect of demand censoring on the optimal policy in newsvendor inventory models with general parametric demand distributions and unknown parameter values we show that the newsvendor problem withobservable lost sales reduces to a sequence of single period problems while the newsvendor problem withunobservable lost sales requires a dynamic analysis using a bayesian markov decision process approach we show that the optimalin ventory level in the presence of censored demand ishigher than would be determined using a bayesian myopic policy we explore the economic rationality for this observation and illustrate it with numerical examples

crop biodiversity risk management and the implications of agricultural assistance this paper presents a theoretical and empirical analysis of the impact of financial assistance to farms on crop biodiversity in an uncertain setting the findings reveal that risk aversion is an important driving force for crop biodiversity conservation risk averse farmers can hedge against the uncertainty they face by allocating land to different crop species however policies intended to stabilize revenues by supporting particular species may alter this link by delinking crop biodiversity from the management of revenues risk

valuing biodiversity for use in pharmaceutical research biodiversity prospecting has been touted as a mechanism for both discovering new pharmaceutical products and saving endangered ecosystems it is unclear what values may arise from such activities however evidence from transactions is incomplete and existing theoretical models are flawed we calculate an upper bound on the value of the marginal species even under favorable assumptions this bound is modest slightly modified assumptions lead to drastically lower estimates we extend our findings to the value of the marginal hectare of habitat and find that the incentives for habitat conservation generated by private pharmaceutical research are also at best very modest

estimating the demand distributions of single period items having frequent stockouts abstract very often the service level of a single period newsboy type product is set at such a low level that i stockouts occur in the majority of the periods and ii a large right hand side of the empirical demand distribution is never observable this paper reports a practical approach for estimating the periodic demand distribution of such a product the approach has three components i using the non parametric product limit method to estimate the fractiles of the observable left hand side of the empirical distribution ii using a subjective approach and an extrapolation of hourly sales approach to fill in the missing right hand side of the empirical distribution iii fitting the estimates obtained in the preceding two components to a tocher curve which can handle the diversity of shapes of a realistic demand distribution and is also computationally very convenient for subsequent calculations for production inventory decisions the entire approach is shown to be simpler but more powerful than existing alternatives for the problem

agrobiodiversity conservation under an imperfect seed system the role of community seed banking schemes the study is an empirical investigation of agrobiodiversity conservation decisions of small farmers in the central highlands of ethiopia the primary objective is to measure the effectiveness of community seed banking csb in enhancing diversity while providing productivity incentives our results indicate a significant impact of participation in csb on farm level agrobiodiversity however the level of biodiversity conservation was not found to have the expected reinforcing impact on participation indicating no support for simultaneity csb participation also led to an increase in productivity consistent with a need for such incentives in order to enhance diversity at a farm level our assessment of the performance of the gls estimator yielded a significant discrepancy between the gls and bootstrap estimates this led to the conclusion that bootstrapping asymptotic estimations might be required for appropriate inference

demand estimation and ordering under censoring stock out timing is almost all you need retailers facing uncertain demand can use observed sales to update demand estimates however such learning is limited by the amount of inventory carried when demand exceeds inventory i e when a stock out event occurs a retailer in general cannot observe actual demand we propose using observations on the timing of sales occurrences in a bayesian fashion to learn about demand and we analyze this learning method for a multiperiod newsvendor setting we find that as previously shown with the use of only stock out event observations the optimal order quantity with timing observations is greater than the optimal order quantity with full demand observations we prove this result using a novel methodology from the statistics literature on comparison of experiments although the optimal over ordering with timing observations tends to be less than that with only stock out event observations in most cases we do observe cases where the opposite is true such cases correspond to high demand uncertainty and low margins where marginal learning from timing observations is significantly higher than using only a stock out event in an extensive numerical study we find that on average and with respect to uncensored demand observations the use of timing observations eliminates 76 1 of the loss in expected profit from using only stock out event observations we show that for poisson and normal demand with unknown mean the proposed learning method is tractable as well as intuitively appealing the information contained in the timing of sales occurrences is fully captured by a single number the timing of stock out we also investigate checkpoint models in which the newsvendor can make observations only at predetermined times in a period and illustrate its convergence to the models with timing and stock out event observations

economic prosperity biodiversity conservation and the environmental kuznets curve many conservationists contend that economic growth and biodiversity conservation are incompatible goals some economists contest this viewpoint arguing that wealthier countries have the luxury of investing more heavily in efforts to conserve biodiversity under this assumption we expect a u shaped relationship between per capita wealth and proportion of species conserved we test this environmental kuznets curve ekc using estimates of per capita income and deforestation rates index of biodiversity threat for 35 tropical countries a prior analysis dietz s adger w n 2003 economic growth biodiversity loss and conservation effort journal of environmental management 68 23 35 using conventional regression techniques failed to provide any support for the parabolic relationship predicted by the ekc hypothesis here we introduce the use of quantile regression and spatial filtering to reanalyze this data addressing issues of heteroskedasticity and spatial autocorrelation we note that preliminary analysis using these methods provides some initial evidence for an ekc however a series of panel analyses with country specific dummy variables eliminated or even reversed much of this support a closer examination of conservation practices and environmental indicators within the countries particularly those countries that drove our initial support suggests that wealth is not a reliable indicator of improved conservation practice our findings indicate that an ekc for biodiversity is overly simplistic and further exploration is required to fully understand the mechanisms by which income affects biodiversity

on crop biodiversity risk exposure and food security in the highlands of ethiopia this paper investigates the effects of crop genetic diversity on farm productivity and production risk in the highlands of ethiopia using a moment based approach the analysis uses a stochastic production function capturing mean variance and skewness effects welfare implications of diversity are evaluated using a certainty equivalent measured as expected income minus a risk premium reflecting the cost of risk we find that the effect of diversity on skewness dominates its effect on variance meaning that diversity reduces the cost of risk the analysis also shows that the beneficial effects of diversity

the economic analysis of biodiversity an assessment biodiversity is complex difficult to define difficult to measure and often involves international and intergenerational considerations biodiversity loss presents significant economic challenges a great deal of economics is required to understand the issues but a simple and important observation is that most species and ecosystems are not traded in markets so prices are often absent and biodiversity is under provided despite the formidable obstacles to high quality economic analysis economics has plenty to offer to biodiversity policy first economic valuation techniques can be employed to roughly estimate the value of the benefits provided by biodiversity and ecosystems second assessing the optimum amount of biodiversity involves recognizing that the conversion of natural capital into manufactured and human capital has so far generated vast amounts of wealth while there may have been too much biodiversity in the past economic analysis suggests that this is a difficult position to hold now third econometric techniques and carefully designed policy studies can assist in determining what policies are most suited to different contexts to cost effectively reduce biodiversity loss fourth political economy is helpful because international coordination is often required ecosystems do not respect national borders and many biodiverse ecosystems are in poorer countries this paper synthesizes the issues and proposes a research agenda which includes improving the measurement and accounting of natural capital improving valuation techniques and theory to provide greater guidance as to the optimum biodiversity and developing our understanding of the merits of different alternatives for government intervention to reduce biodiversity loss

biofuel as social fuel introducing socio environmental services as a means to reduce global inequity the increasing cultivation of energy crops for biofuel production has significantly altered the focus of the agricultural sector but the impact of biofuel production and use is not merely an agricultural one even more importantly it is an issue which likely promotes inequitable conditions and the social conflict of different basic needs within this context the dominant argument criticizes the growing demand for biofuels in the north to compromise food security and sovereignty in the south in order to address these trade offs and conflicts the objective of this paper is the introduction of a conceptual framework of socio environmental services by expanding the construct of environmental services to explicitly include the social dimension it shall accommodate for the fact that the provision of environmental services is often embedded in a complex system of global economic ecological as well as social interdependencies recently the concept of payments for environmental services pes has received much attention with respect to its potential contribution to both environmental sustainability and the economic alleviation of poverty by linking the idea of payments for socio environmental services pses to the three functions of justice its beneficial impact may be more fully tapped

biodiversity poverty and development biodiversity is crucial for the production of a range of marketed and non marketed ecosystem goods and services this paper reviews the empirical evidence for the role of terrestrial biodiversity and biodiversity conservation in economic development and poverty at both the macro e g country and micro e g farm scales it first examines general relationships between biodiversity and economic development before showing how biodiversity influences ecosystem services second future scenarios and challenges for biodiversity and development are examined given projections for further changes in global population economic growth and consumption third the relationship between biodiversity protection and incomes is investigated two specific policies protected areas and bioprospecting are reviewed with respect to their impacts on the welfare of the resource dependent poor in conclusion improvements in policy design and implementation could help minimize the possibility of earth s sixth mass extinction event at least within a few generations while ensuring that the poor are not made worse off as a result of policy implementation

adaptive data driven inventory control with censored demand based on kaplan meier estimator using the well known product limit form of the kaplan meier estimator from statistics we propose a new class of nonparametric adaptive data driven policies for stochastic inventory control problems we focus on the distribution free newsvendor model with censored demands the assumption is that the demand distribution is not known and there are only sales data available we study the theoretical performance of the new policies and show that for discrete demand distributions they converge almost surely to the set of optimal solutions computational experiments suggest that the new policies converge for general demand distributions not necessarily discrete and demonstrate that they are significantly more robust than previously known policies as a by product of the theoretical analysis we obtain new results on the asymptotic consistency of the kaplan meier estimator for discrete random variables that extend existing work in statistics to the best of our knowledge this is the first application of the kaplan meier estimator within an adaptive optimization algorithm in particular the first application to stochastic inventory control models we believe that this work will lead to additional applications in other domains

does poverty constrain deforestation econometric evidence from peru this paper examines the relationship between income and land clearing for households living in tropical forest regions a simple model of the agricultural household that clears land for agriculture is developed to investigate the relationship between lagged income and cleared land holdings analysis of panel data from peru suggests that lagged income is positively correlated with clearing though at a decreasing rate and because of labor market constraints clearing is positively correlated with household labor availability this work suggests that small increases in the incomes of the poorest are unlikely to reduce deforestation in this context

learning consumer tastes through dynamic assortments how should a firm modify its product assortment over time when learning about consumer tastes in this paper we study dynamic assortment decisions in a horizontally differentiated product category for which consumers diverse tastes can be represented as locations on a hotelling line we presume that the firm knows all possible consumer locations comprising a finite set but does not know their probability distribution we model this problem as a discrete time dynamic program each period the firm chooses an assortment and sets prices to maximize the total expected profit over a finite horizon given its subjective beliefs over consumer tastes the consumers then choose a product from the assortment that maximizes their own utility the firm observes sales which provide censored information on consumer tastes and it updates beliefs in a bayesian fashion there is a recurring trade off between the immediate profits from sales in the current period exploitation and the informational gains to be exploited in all future periods exploration we show that one can partially order assortments based on their information content and that in any given period the optimal assortment cannot be less informative than the myopically optimal assortment this result is akin to the well known stock more result in censored newsvendor problems with the newsvendor learning about demand through sales when lost sales are not observable we demonstrate that it can be optimal for the firm to alternate between exploration and exploitation and even offer assortments that lead to losses in the current period in order to gain information on consumer tastes we also develop a bayesian conjugate model that reduces the state space of the dynamic program and study value of learning using this conjugate model

economic and ecological trade offs of agricultural specialization at different spatial scales specialization in agricultural systems can lead to trade offs between economic gains and ecosystem functions we suggest and explore a conceptual framework in which economic gains can be maximized when production activities are specialized at increasingly broader scales from the household to the village region or above particularly when markets for outputs and inputs function well conversely more specialization likely reduces biodiversity and significantly limits ecosystem functions when agricultural specialization increases and moves to broader scales as a result of improved infrastructure and markets or other drivers ecosystem functions can also be endangered at broader spatial scales policies to improve agricultural incomes may influence the level of specialization at different scales and thus affect the severity of the trade offs this paper takes jambi province in indonesia a current hotspot of rubber and oil palm monoculture as a case study to illustrate these issues we empirically show that the level of specialization differs across scales with higher specialization at household and village levels and higher diversification towards the province level we discuss ways to resolve trade offs between economic gains and ecological costs including landscape design targeted policies and adoption of long term perspectives

stalking information bayesian inventory management with unobserved lost sales retailers are frequently uncertain about the underlying demand distribution of a new product when taking the empirical bayesian approach of scarf 1959 they simultaneously stock the product over time and learn about the distribution assuming that unmet demand is lost and unobserved this learning must be based on observing sales rather than demand which differs from sales in the event of a stockout using the framework and results of braden and freimer 1991 the cumulative learning about the underlying demand distribution is captured by two parameters a scale parameter that reflects the predicted size of the underlying market and a shape parameter that indicates both the size of the market and the precision with which the underlying distribution is known an important simplification result of scarf 1960 and azoury 1985 which allows the scale parameter to be removed from the optimization is shown to extend to this setting we present examples that reveal two interesting phenomena 1 a retailer may hope that compared to stocking out realized demand will be strictly less than the stock level even though stocking out would signal a stochastically larger demand distribution and 2 it can be optimal to drop a product after a period of successful sales we also present specific conditions under which the following results hold 1 investment in excess stocks to enhance learning will occur in every dynamic problem and 2 a product is never dropped after a period of poor sales the model is extended to multiple independent markets whose distributions depend proportionately on a single unknown parameter we argue that smaller markets should be given better service as an effective means of acquiring information

the contribution of genetic resources and diversity to wheat production in the punjab of pakistan the ability to meet the world s growing food demand dramatically improved with the release of modern semidwarf or green revolution wheat varieties in the early 1960s despite initial and subsequent success in improving yield potential and yield stability maintaining disease resistance and improving other plant characteristics the green revolution has provoked criticism and debate a major issue in this debate concerns the effect of scientific plant breeding technology on crop genetic diversity which is believed to have important implications for global and national food security and producer welfare

property rights genetic resources and biotechnological change it is well recognized that wild genetic resources the genetic constitutions of plants and animals have substantial social and economic value as repositories of genetic information today genetic information provides direct and indirect inputs into plant breeding programs the development of natural products including drugs and pharmaceuticals and increasingly sophisticated applications of biotechnology 2 recognition of the potential of wild genetic resources in the development of drugs has led the national cancer institute to initiate a massive plant collection project 3 which is a follow up to an earlier 1970s project that sought to identify drugs effective against a variety of cancers and to look at the immune system effects of various drugs it is estimated that 70 percent of the 3 000 species known to have anticancer properties are found in the tropical forests 4 in recent years a number of widely used drugs have been developed from plants including two important anticancer drugs derived from the rosy periwinkle found in tropical madagascar with the recent major breakthroughs in biotechnology the future potential of these resources seems limitless species that have no current commercial application have useful natural chemicals or are as yet undiscovered never