Wheat policy options in Zimbabwe: a comparative advantage approach

A position paper on policy options for Zimbabwe's wheat production self-sufficiency.Zimbabwe is unusual among SADCC countries in producing most of its own wheat. From 1965 to 1975, rapid growth in wheat production transformed the nation from a net wheat importer to a net exporter. Although wheat consumption has since overtaken production and revived the need for imports, domestically-produced wheat continues to make up the major part of supply. Recent developments suggest that Zimbabwe’s current high level of wheat self-sufficiency may be threatened. Demographic and economic factors have increased the demand for bread and other wheat based products more rapidly than domestic wheat production has been able to expand, forcing the government to rely on imports to make up the shortfall. Commercial imports averaged around 100,000 mt in each of the last three years and would have been even greater had the government not imposed limits. Wheat is currently rationed to millers, who claim that demand exceeds the available supply by at least 25-30%. While such figures are difficult to substantiate in the absence of reliable consumption data, the millers’ claims are supported by the appearance in Harare of occasional bread lines.The research supporting the preparation the proceedings papers was financed by the U.S. Agency for International Development, Bureau of Science and Technology; Bureau for Africa; and the Southern Africa Regional Programme

The political economy of wheat consumption and production with special reference to Sub-Saharan Africa.

A position paper on the increased importance of wheat as a staple nutrition cereal in Sub-Saharan Africa.Over the past 25 years, one of the most dramatic changes in dietary patterns in developing countries has been the increasing role of wheat as a staple food. Wheat consumption has risen rapidly both in countries where wheat is a traditional staple (e.g., in the Middle East and North Africa) and in countries where wheat is an "introduced" food, especially in the tropical countries lying between 23°S and 23°N latitude . In most cases, increased wheat consumption has been made possible by rapid increases in imports; over 80% of increased wheat consumption over the past two decades in these two groups of countries has been supplied from wheat imports . Only in the large mixed-cereal economies of India, China, and Mexico that experienced the Green Revolution in wheat production has increased wheat consumption been largely supplied from domestic sources.The research supporting the preparation the proceedings papers was financed by the U.S. Agency for International Development, Bureau of Science and Technology; Bureau for Africa; and the Southern Africa Regional Programme; under a Food Security in Africa cooperative agreemen

Striding out with Parkinson disease: evidence-based physical therapy for gait disorders

Although Parkinson disease (PD) is common throughout the world, the evidence for physical therapy interventions that enable long-term improvement in walking is still emerging. This article critiques the major physical therapy approaches related to gait rehabilitation in people with PD: compensatory strategies, motor skill learning, management of secondary sequelae, and education to optimize physical activity and reduce falls. The emphasis of this review is on gait specifically, although balance and falls are of direct importance to gait and are addressed in that context. Although the researchers who have provided the evidence for these approaches grounded their studies on different theoretical paradigms, each approach is argued to have a valid place in the comprehensive management of PD generally and of gait in particular. The optimal mix of interventions for each individual varies according to the stage of disease progression and the patient's preferred form of exercise, capacity for learning, and age

Resource Recovery from Wastewater Treatment Sludge Containing Gypsum

The disposal of wastewater treatment sludge generated at the Radford Army Ammunition Plant (RAAP) is a serious problem. The sludge is produced by neutralizing spent acid contained in the wastewater with lime, and consists principally of very finely divided wet gypsum (calcium sulfate dihydrate). Although the sludge is presently being disposed of in a landfill, the sludge is difficult to handle and convert into a load-bearing material. Therefore an alternative method of disposal is being developed and evaluated. The alternative method involves drying and granulating the sludge, followed by high temperature calcination in a fluidized bed reactor to recover usable sulfur dioxide and lime. If the method is adopted, these products would be used within the plant with considerable cost savings. The sulfur dioxide would be added to the feed stream of an oleum manufacturing facility and the lime would be reused in wastewater treatment

Should all anticoagulated patients with head injury receive a CT scan? Decision-analysis modelling of an observational cohort

Objectives: It is not currently clear whether all anticoagulated patients with a head injury should receive CT scanning or only those with evidence of traumatic brain injury (e.g. loss of consciousness or amnesia). We aimed to determine the cost-effectiveness of CT for all compared to selective CT use for anticoagulated patients with a head injury. Design: Decision-analysis modelling of data from a multi-centre observational study. Setting: 33 Emergency Departments in England and Scotland. Participants: 3566 adults (aged ≥16 years) who had suffered blunt head injury, were taking warfarin and underwent selective CT scanning. Main outcome measures: Estimated expected benefits in terms of quality-adjusted life years (QALYs) were the entire cohort to receive a CT scan; estimated increased costs of CT and also the potential cost implications associated with patient survival and improved health. These values were used to estimate the cost per QALY of implementing a strategy of CT for all patients compared to observed practice based on guidelines recommending selective CT use. Results: Of the 1420/3534 patients (40%) who did not receive a CT scan, 7 (0.5%) suffered a potentially avoidable head injury related adverse outcome. If CT scanning had been performed in all patients, appropriate treatment could have gained 3.41 additional quality-adjusted life years (QALYs) but would have incurred £193,149 additional treatment costs and £130,683 additional CT costs. The incremental cost-effectiveness ratio of £94,895/QALY gained for unselective compared to selective CT use is markedly above the threshold of £20-30,000/QALY used by the UK National Institute for Care Excellence to determine cost-effectiveness. Conclusions: CT scanning for all anticoagulated patients with head injury is not cost-effective compared with selective use of CT scanning based on guidelines recommending scanning only for those with evidence of traumatic brain injur

Universal Cubic Eigenvalue Repulsion for Random Normal Matrices

Random matrix models consisting of normal matrices, defined by the sole constraint $[N^{\dag},N]=0$, will be explored. It is shown that cubic eigenvalue repulsion in the complex plane is universal with respect to the probability distribution of matrices. The density of eigenvalues, all correlation functions, and level spacing statistics are calculated. Normal matrix models offer more probability distributions amenable to analytical analysis than complex matrix models where only a model wth a Gaussian distribution are solvable. The statistics of numerically generated eigenvalues from gaussian distributed normal matrices are compared to the analytical results obtained and agreement is seen.Comment: 15 pages, 2 eps figures. to appar in Physical Review

Pulmonary MRI contrast using Surface Quadrupolar Relaxation (SQUARE) of hyperpolarized 83Kr

Hyperpolarized 83Kr has previously been demonstrated to enable MRI contrast that is sensitive to the chemical composition of the surface in a porous model system. Methodological advances have lead to a substantial increase in the 83Kr hyperpolarization and the resulting signal intensity. Using the improved methodology for spin exchange optical pumping of isotopically enriched 83Kr, internal anatomical details of ex vivo rodent lung were resolved with hyperpolarized 83Kr MRI after krypton inhalation. Different 83Kr relaxation times were found between the main bronchi and the parenchymal regions in ex vivo rat lungs. The T1 weighted hyperpolarized 83Kr MRI provided a first demonstration of surface quadrupolar relaxation (SQUARE) pulmonary MRI contrast

Curvature correction to the mobility of fluid membrane inclusions

For the first time, using rigorous low-Reynolds-number hydrodynamic theory on curved surfaces via a Stokeslet-type approach, we provide a general and concise expression for the leading-order curvature correction to the canonical, planar, Saffman-Delbrück value of the diffusion constant for a small inclusion embedded in an arbitrarily (albeit weakly) curved fluid membrane. In order to demonstrate the efficacy and utility of this wholly general result, we apply our theory to the specific case of calculating the diffusion coefficient of a locally curvature inducing membrane inclusion. By including both the effects of inclusion and membrane elasticity, as well as their respective thermal shape fluctuations, excellent agreement is found with recently published experimental data on the surface tension dependent mobility of membrane bound inclusions

Nonperturbative renormalization group approach to frustrated magnets

This article is devoted to the study of the critical properties of classical XY and Heisenberg frustrated magnets in three dimensions. We first analyze the experimental and numerical situations. We show that the unusual behaviors encountered in these systems, typically nonuniversal scaling, are hardly compatible with the hypothesis of a second order phase transition. We then review the various perturbative and early nonperturbative approaches used to investigate these systems. We argue that none of them provides a completely satisfactory description of the three-dimensional critical behavior. We then recall the principles of the nonperturbative approach - the effective average action method - that we have used to investigate the physics of frustrated magnets. First, we recall the treatment of the unfrustrated - O(N) - case with this method. This allows to introduce its technical aspects. Then, we show how this method unables to clarify most of the problems encountered in the previous theoretical descriptions of frustrated magnets. Firstly, we get an explanation of the long-standing mismatch between different perturbative approaches which consists in a nonperturbative mechanism of annihilation of fixed points between two and three dimensions. Secondly, we get a coherent picture of the physics of frustrated magnets in qualitative and (semi-) quantitative agreement with the numerical and experimental results. The central feature that emerges from our approach is the existence of scaling behaviors without fixed or pseudo-fixed point and that relies on a slowing-down of the renormalization group flow in a whole region in the coupling constants space. This phenomenon allows to explain the occurence of generic weak first order behaviors and to understand the absence of universality in the critical behavior of frustrated magnets.Comment: 58 pages, 15 PS figure