Cavity state preparation using adiabatic transfer

We show how to prepare a variety of cavity field states for multiple cavities. The state preparation technique used is related to the method of stimulated adiabatic Raman passage or STIRAP. The cavity modes are coupled by atoms, making it possible to transfer an arbitrary cavity field state from one cavity to another, and also to prepare non-trivial cavity field states. In particular, we show how to prepare entangled states of two or more cavities, such as an EPR state and a W state, as well as various entangled superpositions of coherent states in different cavities, including Schrodinger cat states. The theoretical considerations are supported by numerical simulations.Comment: 11 pages, 9 figures. Accepted in Phys. Rev.

Indonesia's palm oil subsector

Debate on Indonesia's palm oil policy was stimulated by a sharp increase in cooking oil prices in 1994-95 and a resulting increase in the export tax rate on crude palm oil. Palm oil has been one of the fastest growing subsectors in Indonesia. Using a quantitative model, the author analyzes the effect of government policies, including the export tax, buffer stock operations by the BULOG (the national logistics agency), and directed sales from public estates. The author acknowledges the export tax's effectiveness in lowering domestic prices, but observes that its impact on inflation and consumer welfare is minimal. The tax has also had the unintended effect of transferring income from oil palm growers located primarily off Java. The structure of the tax discourages local processing by squeezing processing margins. And determining tax rates on palm oil products independent from the underlying crude palm oil price creates uncertainty about marketing margins for processors. The author recommends repealing the tax and discontinuing buffer stock operations and directed sales from public estates. The author concludes with recommendations on investment policy. Direct incentives to private investors have been used to overcome investment risks and uncertainties, but investors should no longer need those incentives. Instead, Indonesia's government should focus more on alleviating obstacles to private investment. The Bank might be of assistance in this area.Markets and Market Access,Environmental Economics&Policies,Economic Theory&Research,Payment Systems&Infrastructure,Consumption,Economic Theory&Research,Consumption,Environmental Economics&Policies,Markets and Market Access,Access to Markets

Cast Fe-base cylinder/regenerator housing alloy

The development of an iron-base alloy that can meet the requirements of automotive Stirling engine cylinders and regenerator housings is described. Alloy requirements are as follows: a cast alloy, stress for 5000-hr rupture life of 200 MPa (29 ksi) at 775 C (1427 F), oxidation/corrosion resistance comparable to that of N-155, compatibility with hydrogen, and an alloy cost less than or equal to that of 19-9DL. The preliminary screening and evaluation of ten alloys are described

Monte Carlo simulation by computer for life-cycle costing

Prediction of behavior and support requirements during the entire life cycle of a system enables accurate cost estimates by using the Monte Carlo simulation by computer. The system reduces the ultimate cost to the procuring agency because it takes into consideration the costs of initial procurement, operation, and maintenance

The "Mysterious" Origin of Brown Dwarfs

Hundreds of brown dwarfs (BDs) have been discovered in the last few years in stellar clusters and among field stars. BDs are almost as numerous as hydrogen burning stars and so a theory of star formation should also explain their origin. The ``mystery'' of the origin of BDs is that their mass is two orders of magnitude smaller than the average Jeans' mass in star--forming clouds, and yet they are so common. In this work we investigate the possibility that gravitationally unstable protostellar cores of BD mass are formed directly by the process of turbulent fragmentation. Supersonic turbulence in molecular clouds generates a complex density field with a very large density contrast. As a result, a fraction of BD mass cores formed by the turbulent flow are dense enough to be gravitationally unstable. We find that with density, temperature and rms Mach number typical of cluster--forming regions, turbulent fragmentation can account for the observed BD abundance.Comment: 11 pages, 3 figures, ApJ submitted Error in equation 1 has been corrected. Improved figure

Sugar policy and reform

Reviewing cross-country experience with sugar policies, and policy reform, the authors conclude that long-standing government interventions - rooted in historical trade arrangements, fear of shortages, and conflicting interests between growers, and sugar mills - often displace both the markets, and the institutions required to produce efficient outcomes. Arrangements rooted in colonial eras, still shape policies, and trade in the United States, the European Union (EU), and many developing countries. Once policies, and institutions are put in place, households, and the value of investments grow dependent on them, even as their usefulness fades. Firms and households make decisions that are costly to reverse. And the result is a legacy of path-dependent policies, in which approaches, and instruments are greatly influenced by past agreements, and previous interventions. The cumulative effects of these interventions are embodied in livelihoods, political institutions, capital stocks, and factor markets - which not only dictate the starting point for reform, but also determine which reform paths are feasible. Experiments with public ownership, common in many countries, have not succeeded. So most countries have initiated some measure of market reform. And events relating to NAFTA, Lome, and expansion of the EU, may bring about significant changes in the EU, and US sugar regimes, with cascading effects on other countries. Common problems in the sector include determining cane quality, finding methods for fairly sharing revenues from joint production, finding ways to take advantage of preferential trade arrangements with minimal negative consequences, finding ways to finance, and encourage research, and other activities with common benefits, identifying practices that facilitate equitable, sustainable privatization, and determining the relationship between sugar market reform, and markets in land, water, credit, and other inputs.Food&Beverage Industry,Environmental Economics&Policies,Agribusiness,Agribusiness&Markets,Economic Theory&Research,Environmental Economics&Policies,Agribusiness&Markets,Economic Theory&Research,Agribusiness,Agricultural Trade

Risks, lessons learned, and secondary markets for greenhouse gas reductions

Collectively or individually, countries are likely to implement policies designed to limit greenhouse gas emissions. Experience from tradable quota schemes suggests that emissions trading could significantly reduce the costs of emission limits. The Kyoto Protocol provides the framework for a common trading mechanism for all countries - including countries that would not face immediate emission limits. Significantly, the Protocol places the responsibility for meeting emission limits with national governments. How policymakers choose to implement emission limits will significantly shape the incentives that drive evolving secondary markets for greenhouse-gas-based instruments. Potential market participants who were surveyed rate policy-related risk as higher than business-related risks. Domestic polices designed to reduce fragmentation in secondary markets, establish clear baselines and procedures, and strengthen host-country institutions can all help reduce the risks and costs of emission limits.Economic Theory&Research,Labor Policies,Payment Systems&Infrastructure,Environmental Economics&Policies,Health Economics&Finance,Health Economics&Finance,Environmental Economics&Policies,Carbon Policy and Trading,Energy and Environment,Economic Theory&Research

The effects of option hedging on the costs of domestic price stabilization schemes

Casual observation leads to the conclusion that stabilization funds tend to be short-lived. While it may be that some funds have failed due to poor management or unwarranted political interventions, the stochastic components of commodity prices can generate insurmountable difficulties for even the most expert managers. Price-band schemes contain an element of information feed-back and offer transparent rules -- attributes which make such schemes preferable to many alternative mechanisms -- but the benefits to producers tend to be, on average, quite small. Similar average benefits can be generated with very small import taxes or producer subsidies. Nevertheless, such schemes can have large single-year effects. The simulation results demonstrate that, if adopted, such funds should be hedged unless the government is not at all adverse to the fund's financial failure. Still, hedged or unhedged, such funds will, with eventual certainty, generate large levels of debt as a statistically"rare"sequence of events must eventually occur. By hedging, the funds are more likely to survive in the short-run.Environmental Economics&Policies,Access to Markets,Markets and Market Access,Economic Theory&Research,Insurance&Risk Mitigation

Resource management and the effects of trade on vulnerable places and people : lessons from six case studies

Lessons from six case studies illustrate the complex relationships between international trade, vulnerable ecologies and the poor. The studies, taken from Africa, Asia and Latin America and conducted by local researchers, are set in places where the poor live in close proximity to ecologies that are important to global conservation efforts, and focus on the cascading consequences of trade policy for local livelihoods and environmental services. Collectively, the studies show how under-valued common resources are often poorly protected and consequently subject to shifting economic incentives, including those that arise from trade. The studies provide examples where trade works to accelerate the use of natural resources and to exacerbate unsustainable dependencies by the poor, and other examples where trade has the opposite effect. An important conclusion is that local livelihood and technology choices have important consequences for how environmental resources are used and should be taken into account when designing policies to safeguard fragile ecologies.Environmental Economics&Policies,Economic Theory&Research,Emerging Markets,Labor Policies,Population Policies

The performance of Bulgarian food markets during reform

Food policy often depends on markets and markets depend on institutions. But how good do institutions have to be before reforms can be launched? Relying on well timed surveys of agricultural prices and a joint study by the Government of Bulgaria and the World Bank on agricultural market institutions, this paper presents evidence that performance in food markets improved following significant policy reforms in Bulgaria, although public institutions remained weak. This suggests that even though strong institutions are preferred to weak ones, it can be costly and impractical to delay policy reforms until work on strengthening institutions is finished. Still, measured performance varied by place and by commodity, suggesting that markets developed at different tempos and that the distribution of benefits from improved markets was uneven. This points to the need to address the costs of adjustment as policies change. The paper introduces a new approach to measure market performance based on composite-error techniques.Markets and Market Access,Transport Economics Policy&Planning,Economic Theory&Research,Access to Markets,Agribusiness