Efficiency Effects Zimbabwe’s Agricultural Mechanization and Fast Track Land Reform Programme: A Stochastic Frontier Approach

A development goal pursued by the Zimbabwean government even before the much-maligned fast track land reform programme (FTLRP) was expansion of agricultural production through agricultural mechanization. This goal has been pursued through the acquisition and use of tractors by arable crop farmers in communal and resettlement state land delineated during the period following the launch of the FTLRP. This research project investigated the combined impacts of mechanization and an unplanned land reform on agricultural productivity in the Bindura district of Zimbabwe. The existing land policy and the issue of technical efficiency in agricultural productivity are assumed to be the drivers of the programme. It is likely that these issues will be important considerations in determining the sustainability of the mechanization policy. A multistage sampling technique was used to randomly select 90 farmers in the study area and structured questionnaires were used to collect demographic, investment and production data which were subsequently fitted by means of the Stochastic Frontier Model. Results revealed that mechanization was an important factor in the performance of the farmers who participated in the programme. The results also suggest that availability of land and access to production resources are crucial to farm productivity. Despite these, overall production and productivity remain low and the hyperinflationary situation triggered by supply constraints are only beginning to slightly ease. As the national unity government grapples with the huge task to restore growth in the Zimbabwean economy, it is important that these issues are borne in mind.Technical Constraints, Market Access, Agricultural Development, Induced Innovation Model, The Stochastic Frontier model, The Productive Efficiency and Mandate of Extension, Farm Management,

Performance of Smallholder Agriculture Under Limited Mechanization and the Fast Track Land Reform Program in Zimbabwe

agricultural mechanization, fast track land reform, agricultural development, Stochastic Frontier model, technical efficiency, agribusiness management, Agricultural and Food Policy, Community/Rural/Urban Development, International Development, Land Economics/Use, Resource /Energy Economics and Policy,

Top-loading Small-sample Calorimeters for Measurements as a Function of Magnetic Field Angle

In quasi-low-dimensional systems, the existence of a particular physical state and the temperature and magnetic-field-dependence of its phase boundary often strongly depends on magnetic field orientation. To investigate magnetic field orientation dependent phase transitions in these materials, we have developed rotatable miniature and sub-miniature sample-in-vacuum calorimeters that operate in dc magnetic fields up to 18 and 45 tesla. The calorimeters cover the temperature range from below 0.1 K to above 10 K; they are able rotate a full 360 degrees relative to the applied magnetic field while remaining at base temperature. Samples are typically ontheorderof1mginmassandupto2mm2 x0.5mminvolume

Calorimetric Measurements of Magnetic-Field-Induced Inhomogeneous Superconductivity Above The Paramagnetic Limit

We report the first magneto-caloric and calorimetric observations of a magnetic-field-induced phase transition within a superconducting state to the long-sought exotic "FFLO" superconducting state first predicted over 50 years ago. Through the combination of bulk thermodynamic calorimetric and magnetocaloric measurements in the organic superconductor $\kappa$ - (BEDT-TTF)$_2$Cu(NCS)$_2$, as a function of temperature, magnetic field strength, and magnetic field orientation, we establish for the first time that this field-induced first-order phase transition at the paramagnetic limit $H_p$ for traditional superconductivity is to a higher entropy superconducting phase uniquely characteristic of the FFLO state. We also establish that this high-field superconducting state displays the bulk paramagnetic ordering of spin domains required of the FFLO state. These results rule out the alternate possibility of spin-density wave (SDW) ordering in the high field superconducting phase. The phase diagram determined from our measurements --- including the observation of a phase transition into the FFLO phase at $H_p$ --- is in good agreement with recent NMR results and our own earlier tunnel-diode magnetic penetration depth experiments, but is in disagreement with the only previous calorimetric report.Comment: 5 pages, 5 figure

The Complexity of Graph-Based Reductions for Reachability in Markov Decision Processes

We study the never-worse relation (NWR) for Markov decision processes with an infinite-horizon reachability objective. A state q is never worse than a state p if the maximal probability of reaching the target set of states from p is at most the same value from q, regard- less of the probabilities labelling the transitions. Extremal-probability states, end components, and essential states are all special cases of the equivalence relation induced by the NWR. Using the NWR, states in the same equivalence class can be collapsed. Then, actions leading to sub- optimal states can be removed. We show the natural decision problem associated to computing the NWR is coNP-complete. Finally, we ex- tend a previously known incomplete polynomial-time iterative algorithm to under-approximate the NWR

TB biomarkers, TB correlates and human challenge models: New tools for improving assessment of new TB vaccines

SummaryThe 4th Global Forum on TB Vaccines, convened in Shanghai, China, from 21 – 24 April 2015, brought together a wide and diverse community involved in tuberculosis vaccine research and development to discuss the current status of, and future directions for this critical effort. This paper summarizes the sessions on Biomarkers and Correlates, and Human Challenge Models. Summaries of all sessions from the 4th Global Forum are compiled in a special supplement of Tuberculosis. [August 2016, Vol 99, Supp S1, S1–S30]

Maximum Edge-Disjoint Paths in kk-sums of Graphs

We consider the approximability of the maximum edge-disjoint paths problem (MEDP) in undirected graphs, and in particular, the integrality gap of the natural multicommodity flow based relaxation for it. The integrality gap is known to be $\Omega(\sqrt{n})$ even for planar graphs due to a simple topological obstruction and a major focus, following earlier work, has been understanding the gap if some constant congestion is allowed. In this context, it is natural to ask for which classes of graphs does a constant-factor constant-congestion property hold. It is easy to deduce that for given constant bounds on the approximation and congestion, the class of "nice" graphs is nor-closed. Is the converse true? Does every proper minor-closed family of graphs exhibit a constant factor, constant congestion bound relative to the LP relaxation? We conjecture that the answer is yes. One stumbling block has been that such bounds were not known for bounded treewidth graphs (or even treewidth 3). In this paper we give a polytime algorithm which takes a fractional routing solution in a graph of bounded treewidth and is able to integrally route a constant fraction of the LP solution's value. Note that we do not incur any edge congestion. Previously this was not known even for series parallel graphs which have treewidth 2. The algorithm is based on a more general argument that applies to $k$-sums of graphs in some graph family, as long as the graph family has a constant factor, constant congestion bound. We then use this to show that such bounds hold for the class of $k$-sums of bounded genus graphs

Charge Ordering in alpha-(BEDT-TTF)2I3 by synchrotron x-ray diffraction

The spatial charge arrangement of a typical quasi-two-dimensional organic conductor alpha-(BEDT-TTF)2I3 is revealed by single crystal structure analysis using synchrotron radiation. The results show that the horizontal stripe type structure, which was suggested by mean field theory, is established. We also find the charge disproportion above the metal-insulator transition temperature and a significant change in transfer integrals caused by the phase transition. Our result elucidates the insulating phase of this material as a 2k_F charge density localization.Comment: 8 pages, 5 figures, 1 tabl

Spectroscopy of 18^{18}Na: Bridging the two-proton radioactivity of 19^{19}Mg

The unbound nucleus $^{18}$Na, the intermediate nucleus in the two-proton radioactivity of $^{19}$Mg, was studied by the measurement of the resonant elastic scattering reaction $^{17}$Ne(p,$^{17}$Ne)p performed at 4 A.MeV. Spectroscopic properties of the low-lying states were obtained in a R-matrix analysis of the excitation function. Using these new results, we show that the lifetime of the $^{19}$Mg radioactivity can be understood assuming a sequential emission of two protons via low energy tails of $^{18}$Na resonances