Single spin asymmetry in inclusive pion production, Collins effect and the string model

We calculate the single spin asymmetry in the inclusive pion production in proton-proton collisions. We generate the asymmetry at the level of fragmentation function (Collins effect) by the Lund coloured string mechanism. We compare our results with the Fermilab E704 data from polarized proton-proton collisions at 200 GeV. We show that the transversely polarized quark densities at high Bjorken x strongly differ from these predicted by the SU(6) proton wave function.Comment: (11 pages in TeX; 7 figures in PS files available upon request) LYCEN/9423, TPJU 12/9

Neutrino Oscillations in Intermediate States.II -- Wave Packets

We analyze oscillations of intermediate neutrinos in terms of the scattering of particles described by Gaussian wave packets. We study a scalar model as in a previous paper (I) but in realistic situations, where the two particles of the initial state and final state are wave packets and neutrinos are in the intermediate state. The oscillation of the intermediate neutrino is found from the time evolution of the total transition probability between the initial state and final state. The effect of a finite lifetime and a finite relaxation time are also studied. We find that the oscillation pattern depends on the magnitude of wave packet sizes of particles in the initial state and final state and the lifetime of the initial particle. For $\Delta m^2_{21}=3\times 10^{-2}$ eV$^2$, the oscillation probability deviates from that of the standard formula if the wave packet sizes are around $10^{-13}$ m for 0.4 MeV neutrino.Comment: 29 pages, 11 figures. typos corrected, appendix adde

Commodity risk management and development

In 1995, 57 countries depended on three commodities for more than half their exports, reports UNCTAD. And commodities, fuels, grains, and oilseeds are important imports for several countries. The notorious volatility of commodity prices is a major source of instability and uncertainty in commodity-dependent countries, affecting governments, producers (farmers), traders, processors, and financial institutions. Further, commodity price instability has a negative impact on economic growth, income distribution, and poverty alleviation. Early attempts to deal with commodity price volatility relied on buffer stocks, buffer funds, government intervention in commodity markets, and international commodity agreements to stabilize prices. These were largely unsuccessful--sometimes spectacularly so. Buffer funds went bankrupt, commodity agreements were suspended, buffer stocks proved ineffective, and government intervention was both costlyand ineffective. As the poor performance of such stabilization schemes became more evident, academics and policymakers began distinguishing between programs that tried to alter price distribution (domestically or internationally) and programs that used market-based approaches for dealing with market uncertainty. This change in approach coincided with a significant rise in the use of market-based commodity risk management instruments--aided by the liberalization of markets, the lowering of trade and capital control barriers, and the globalization of commodity markets. by the mid-1990s, several governments, state companies, and private sector participants began using commodity derivatives markets to hedge their commodity price risks. Participation in those markets is growing, but important barriers to access remain including counterparty risk, problems small groups (such as farmers) have aggregating risks, basis risks (no correlation of local and international prices), no local reference prices, low liquidity, no derivatives markets for certain products, and low levels of know-how. International institutions, local governments, and the private sector could facilitate developing countries access to derivatives markets and the use of risk management tools to solve public sector problems.Economic Theory&Research,Payment Systems&Infrastructure,Environmental Economics&Policies,Markets and Market Access,Labor Policies,Health Economics&Finance,Insurance&Risk Mitigation,Environmental Economics&Policies,Access to Markets,Markets and Market Access

Generalized formulation of theoretical maximum energy efficiency of light-powered systems based on photon entropy analysis

Certain questions regarding the analysis of theoretical maximum energy efficiency $\eta_{max}$ of light-powered systems by the radiant temperature and its use for the Boltzmann coefficient remain unanswered. A potential reason for this could be the confusion about equilibrium and reversibility. Therefore, this study performed a quantum statistical entropy analysis of a light-powered system based on reversibility as the solely essential condition and without recourse to the concept of radiation temperature. Several quantitative analyses that cannot be performed with radiation temperature can be performed using the generalized formula. As examples, this study presents the formulation of $\eta_{max}$ considering the entropy change caused by photochemical reactions, such as that in photosynthesis and photosynthetically active radiation (PAR), and the formulations of several quantities under radiation with arbitrary $\Omega$ and P. Furthermore, analysis from this study found that $\eta_{max}$ decreases as the light absorption rate increases, which had not previously been considered. This general formula is presented, which fills the gap between the Jeter efficiency (Carnot efficiency) $\eta_{C}=1-T_{out}/T_{in}$ and the Spanner efficiency $\eta_{S}$=1-(4/3)$T_{out}$/$T_{in}$ (where $T_{out}$ is ambient temperature and $T_{in}$ is the temperature in the system) for black-body radiation. The analyses generally formulated in this study allow practical analyses of systems such as photosynthesis and photovoltaics, under various conditions relating to sunlight scattered through the atmosphere. Finally, it is proved with elementary geometry that the total entropy of the solar radiation from the Sun to the upper atmosphere of the Earth remains at a constant value. This means that the use of solar energy on satellites in space is expected to be more efficient than on the earth's surface.Comment: 59 Pages, 7 Figures, 5 Appendices, The displayed abstract is shorter than one in the main body due to character limi

An Evaluation System for Steel Structures of Hydroelectric Power Stations based on Fault Tree Analysis and Performance Maps

This paper presents an evaluation system for steel structures of hydroelectric power stations, including hydraulic gates and penstocks, based on Fault Tree Analyasis (FTA) and performance maps. This system consists of fault tree diagrams of FTA, performance maps, design and analysis systems, and engineerin databases. These four modules are integrated by appropriate hyperlinks so that the user of this system can use it easily and seamlessly. A well developed system was applied to some illustrative example cases, and they showed that the developed methodology and system worked well and the users found the system useful and effective for their maintenance tasks at powerstations

Concentration of Bid Prices Just Above the Standard Minimum Price in Public Construction Works

In Japan, contract offices are mandated to set threshold prices for public works. A threshold price is the upper limit of the bid price, and a contractor who exceeds this threshold is disqualified. Furthermore, based on the threshold price, a minimum price is set as a price requiring investigation before acceptance. In recent years, bids and contracts for public works have generally had bid prices concentrated slightly above the standard minimum for investigation. It has been pointed out that this tendency is detrimental in terms of the motivation of engineers and social costs. In this study, we confirm that this tendency was alleviated and that the level of the winning bidder's technical evaluation score was feasible at the same time. In addition, we obtained quantitative findings on variables that affect both above. Furthermore, although it is impossible to achieve a perfect balance between alleviating the tendency of prices to concentrate slightly above the standard minimum for investigation and sufficient technical evaluation scores, elements necessary to improve the overall situation were quantitatively identified