Multiple resonance compensation for betatron coupling and its equivalence with matrix method

Analyses of betatron coupling can be broadly divided into two categories: the matrix approach that decouples the single-turn matrix to reveal the normal modes and the hamiltonian approach that evaluates the coupling in terms of the action of resonances in perturbation theory. The latter is often regarded as being less exact but good for physical insight. The common opinion is that the correction of the two closest sum and difference resonances to the working point is sufficient to reduce the off-axis terms in the 4X4 single-turn matrix, but this is only partially true. The reason for this is explained, and a method is developed that sums to infinity all coupling resonances and, in this way, obtains results equivalent to the matrix approach. The two approaches is discussed with reference to the dynamic aperture. Finally, the extension of the summation method to resonances of all orders is outlined and the relative importance of a single resonance compared to all resonances of a given order is analytically described as a function of the working point.Comment: 22 pages, 10 figure

Household's vulnerability to shocks in Zambia

Zambia is a county characterized by a high incidence of poverty and exposure to several types of shocks like HIV/AIDS, macroeconomic instability and periodic droughts. In this paper the authors conduct an in depth analysis of the incidence and impact of those shocks on poverty. The analysis of the HIV/AIDS epidemic, carried out using the data on the occurrence of the death of an adult in the previous 12 months and the existence of foster children, shows the existence of a generaldecrease in consumption with the exception of non poor rural families. The deterioration of the economic situation and the related high level of unemployment resulted in a lower level of economic wellbeing. Finally, the analysis of the impact of the drought shows that while a significant percentage (17 percent) of the poorest households in rural areas would experience significant losses in maize production (covering 8 percent of all the households), they are concentrated in a few communities in Southern, Central and Western provinces. In order to identify those households that might suffer more from the negative impact of the shocks and/or have a low level of human capital the authors defined"vulnerable households", those that are likely to be poor and exposed to shocks, and"chronically poor households", those that are likely to be poor and have low levels of human capital outcomes. According to this definition, about 20 percent of the households are vulnerable whilst almost 40 percent are chronically poor and 10 percent are at the same time both vulnerable and chronically poor and therefore at most risk. Private coping mechanisms and private transfers are very common, but they do not seem to be effective in helping households to deal with the adverse impact of shocks. On the other hand, household participation in food for work programs increase after the death of a household member. Therefore there is a need for long term household human capital investments, programs to alleviate the burden of HIV/AIDS, and targeted programs for the alleviating weather related shocks like the drought.Rural Poverty Reduction,Services&Transfers to Poor,Poverty Assessment,Small Area Estimation Poverty Mapping,Housing&Human Habitats

Interplay between electron-electron and electron-vibration interactions on the thermoelectric properties of molecular junctions

The linear thermoelectric properties of molecular junctions are theoretically studied close to room temperature within a model including electron-electron and electron-vibration interactions on the molecule. A nonequilibrium adiabatic approach is generalized to include large Coulomb repulsion through a self-consistent procedure and applied to the investigation of large molecules, such as fullerenes, within the Coulomb blockade regime. The focus is on the phonon thermal conductance which is quite sensitive to the effects of strong electron-electron interactions within the intermediate electron-vibration coupling regime. The electron-vibration interaction enhances the phonon and electron thermal conductance, and it reduces the charge conductance and the thermopower inducing a decrease of the thermoelectric figure of merit. For realistic values of junction parameters, the peak values of the thermoelectric figure of merit are still of the order of unity since the phonon thermal conductance can be even smaller than the electron counterpart.Comment: 8 pages, 1 Appendix, 12 pages. arXiv admin note: substantial text overlap with arXiv:1406.377

Electron-vibration effects on the thermoelectric efficiency of molecular junctions

The thermoelectric properties of a molecular junction model, appropriate for large molecules such as fullerenes, are studied within a non-equilibrium adiabatic approach in the linear regime at room temperature. A self-consistent calculation is implemented for electron and phonon thermal conductance showing that both increase with the inclusion of the electron-vibration coupling. Moreover, we show that the deviations from the Wiedemann-Franz law are progressively reduced upon increasing the interaction between electronic and vibrational degrees of freedom. Consequently, the junction thermoelectric efficiency is substantially reduced by the electron-vibration coupling. Even so, for realistic parameters values, the thermoelectric figure of merit can still have peaks of the order of unity. Finally, in the off-resonant electronic regime, our results are compared with those of an approach which is exact for low molecular electron densities. We give evidence that in this case additional quantum effects, not included in the first part of this work, do not affect significantly the junction thermoelectric properties in any temperature regime.Comment: 15 pages, 11 figures, 2 Appendice

In-kind transfers and household food consumption

This paper examines the impact of wheat transfers and cash incomes on wheat consumption and wheat markets. Using propensity score- matching techniques, the total marginal propensity to consume (MPC) for wheat is, on average, 0.33, ranging from essentially zero for Food For Work (a program with large transfers) to 0.51 for Food For Education. Econometric estimates indicate that the MPC for small wheat transfers to poor households is approximately 0.25, while the MPC for wheat out of cash income is near zero. This increase in demand for wheat reduces the potential price effect of three major targeted programs involving small rations (Food For Education, Vulnerable Group Development, and Vulnerable Group Feeding) by about one-third.Transfer payments. ,Incomes. ,Wheat. ,Wheat Economic aspects Bangladesh. ,Food consumption. ,Cereal crops. ,Education. ,Labor. ,Access to education. ,

The Food For Education program in Bangladesh

The Government of Bangladesh launched the innovative Food for Education (FFE) program in 1993. The FFE program provides a free monthly ration of rice or wheat to poor families if their children attend primary school. The goals of this program are to increase primary school enrollment, promote attendance, reduce dropout rates, and enhance the quality of education. This paper presents the findings of a recent International Food Policy Research Institute (IFPRI) evaluation of the FFE program that demonstrates the extent to which these goals were met. This evaluation uses primary data collected from multiple surveys covering schools, households, communities, and foodgrain dealers. The authors first examine the performance of the FFE program, showing that it has largely fulfilled its objectives of increasing school enrollment, promoting school attendance, and preventing dropouts. The enrollment increase was greater for girls than for boys. The quality of education, however, remains a problem. Next, they analyze the targeting effectiveness of the program, its impact on food security, and its efficiency in distributing rations. In general, the FFE program targets low-income households. However, there is considerable scope for improving targeting, as a sizable number of poor households remain excluded from the program even while many nonpoor households are included. Furthermore, the evaluation results indicate that the functioning of the current private-dealer-based foodgrain distribution system of the FFE program is not satisfactory.School children Food ,