Agricultural Efficiency Gains and Trade Liberalization in Sudan

The traditional agriculture in Sudan occupies 60% of the total cultivated land and employs 65% of the agricultural population. Nevertheless, it is characterized by its low crop productivity, which is mainly driven by low technical efficiency, while drought and civil conflicts threaten most of its areas countrywide. Therefore, it has contributed only an average of 16% to the total agricultural GDP during the last decade. This paper addresses from an empirical point of view the sectoral and macroeconomic implications of agricultural efficiency improvement in Sudan and assesses the efficiency gains under the assumption of trade liberalization. Efficiency improvement experiments are implemented by augmenting the efficiency parameters of labor, capital, and land in a Computable General Equilibrium (CGE) framework. The CGE model of the study relies on the newly produced Sudanese Social Accounting Matrix (SAM), which provides data on 10 agricultural sectors, 10 industrial sectors and 13 service sectors. Results show that improving the agricultural efficiency would lead to improvements in GDP, welfare level, and trade balance. In addition it would also improve the output and competitiveness of the Sudanese agricultural exports and increase their strength to face the challenges of liberalization.Agricultural efficiency, liberalization, Sudan SAM, CGE analysis, Agribusiness, Agricultural and Food Policy, Agricultural Finance, Consumer/Household Economics, Crop Production/Industries, Food Security and Poverty, Labor and Human Capital, Land Economics/Use, Production Economics, Productivity Analysis, D2, D5, D6, E1, E2, F1, F2, H2,

Optical manipulation of atoms and molecules using structured light

The interaction of atoms and molecules with structured light, specifically laser light endowed with the property of orbital angular momentum, such as Laguerre-Gaussian light, is discussed. The primary effects of interest here are the influence of the light on the gross motion of atoms and molecules and the possibilities this motion provides for particle manipulation in cooling, heating and trapping experiments. It turns out that, in addition to the possibility of modifying translational motion, suitably structured light can facilitate the manipulation of rotational motion. The latter possibility arises from a light-induced torque that is directly attributable to the orbital angular momentum property of the light. We outline the physics responsible for these effects and consider applications to typical cases in which atoms and ions are subject to near resonant Laguerre-Gaussian beams, leading to characteristic trajectories and eventual trapping in specific regions. Details are given for optical molasses configurations based on twisted light beams arranged in one-, two- and three-dimensional counter-propagating pairs. We extend consideration to the case of liquid crystals, subject to Laguerre-Gaussian light tuned far off-resonance, and show how this leads to the twisting of the directors in the liquid crystal, coinciding with the intensity distribution of the light