Increasing Profitability of Small Scale Orchard Producers through Optimizing Replacement Rate: The Case Study of Ghana

This study sets out to empirically estimate the optimum annual replacement rate and age of cocoa trees in order to maximize the net present value of four common cocoa production systems. The study examines the costs and returns of four common cocoa production systems in Ghana associated with changes in cocoa prices, fertilizer prices, inflation rates, and labor prices. While this study focuses on cocoa, the methodology is applicable to any perennial crop. This study uses empirical yield curves and cost of production data from Ghana to determine when and what percentage of a cocoa orchard should be replaced annually to maximize net present value of revenues over time. Successive versions of the model are solved to determine how input and output price changes affect optimal replacement rates and replacement ages. Producers in both high- and low-income countries are reluctant to cull still productive assets, such as trees that are diminishing in yield over time. The Excel based model developed in this study could provide extension personnel with a simple yet powerful tool to illustrate to producers the benefits of systematic tree replacement. This study provides strong evidence of the benefits of replacing trees at the optimal time and rate.Cocoa, Replacement Rate, Net Present Value (NPV), Production Economics, Q01, Q15, Q32,

Decision problems, complexity, traces, and representations

In this article, we study connections between representation theory and efficient solutions to the conjugacy problem on infinitely generated groups. The main focus is on the conjugacy problem in conjugacy separable groups, where we measure efficiency in terms of the size of the quotients required to distinguish a distinct pair of conjugacy classes

Science, innovation and technology transfer pathways in translational research: a study of divergent trajectories in the healthcare sector in Europe

The geography of the biomedical sector, that of clustering in particular regions, presents an opportunity for place-specific understanding of processes involved in translational research in medical sciences, particularly with regard to the role of public policy and its outcomes in four bioscience regions in Europe

First principles calculation of vibrational Raman spectra in large systems: signature of small rings in crystalline SiO2

We present an approach for the efficient calculation of vibrational Raman intensities in periodic systems within density functional theory. The Raman intensities are computed from the second order derivative of the electronic density matrix with respect to a uniform electric field. In contrast to previous approaches, the computational effort required by our method for the evaluation of the intensities is negligible compared to that required for the calculation of vibrational frequencies. As a first application, we study the signature of 3- and 4-membered rings in the the Raman spectra of several polymorphs of SiO2, including a zeolite having 102 atoms per unit cell.Comment: 4 pages, 2 figures, revtex4 Minor corrections; accepted in Phys. Rev. Let

Computing SL(2,C) Central Functions with Spin Networks

Let G=SL(2,C) and F_r be a rank r free group. Given an admissible weight in N^{3r-3}, there exists a class function defined on Hom(F_r,G) called a central function. We show that these functions admit a combinatorial description in terms of graphs called trace diagrams. We then describe two algorithms (implemented in Mathematica) to compute these functions.Comment: to appear in Geometriae Dedicat

Gas loading of graphene-quartz surface acoustic wave devices

Copyright © 2013 AIP PublishingGraphene was transferred to the propagation path of quartz surface acoustic wave devices and the attenuation due to gas loading of air and argon measured at 70 MHz and 210 MHz and compared to devices with no graphene. Under argon loading, there was no significant difference between the graphene and non-graphene device and the values of measured attenuation agree well with those calculated theoretically. Under air loading, at 210 MHz, there was a significant difference between the non-graphene and graphene devices, with the average value of attenuation obtained with the graphene devices being approximately twice that obtained from the bare quartz devices.Royal Societ

Statins and Exercise Training Response in Heart Failure Patients: Insights From HF-ACTION.

OBJECTIVES: The aim of this study was to assess for a treatment interaction between statin use and exercise training (ET) response. BACKGROUND: Recent data suggest that statins may attenuate ET response, but limited data exist in patients with heart failure (HF). METHODS: HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) was a randomized trial of 2,331 patients with chronic HF with ejection fraction ≤35% who were randomized to usual care with or without ET. We evaluated whether there was a treatment interaction between statins and ET response for the change in quality of life and aerobic capacity (peak oxygen consumption and 6-min walk distance) from baseline to 3 months. We also assessed for a treatment interaction among atorvastatin, simvastatin, and pravastatin and change in these endpoints with ET. Multiple linear regression analyses were performed for each endpoint, adjusting for baseline covariates. RESULTS: Of 2,331 patients in the HF-ACTION trial, 1,353 (58%) were prescribed statins at baseline. Patients treated with statins were more likely to be older men with ischemic HF etiology but had similar use of renin angiotensin system blockers and beta-blockers. There was no evidence of a treatment interaction between statin use and ET on changes in quality of life or exercise capacity, nor was there evidence of differential association between statin type and ET response for these endpoints (all p values \u3e0.05). CONCLUSIONS: In a large chronic HF cohort, there was no evidence of a treatment interaction between statin use and short-term change in aerobic capacity and quality of life with ET. These findings contrast with recent reports of an attenuation in ET response with statins in a different population, highlighting the need for future prospective studies. (Exercise Training Program to Improve Clinical Outcomes in Individuals With Congestive Heart Failure; NCT00047437)

Addressing Profound Disadvantages to Improve Indigenous Health and Reduce Hospitalisation: A Collaborative Community Program in Remote Northern Territory

BACKGROUND: Aboriginal people in rural and remote areas of the Northern Territory of Australia have suffered longstanding issues of homelessness and profound health and social inequities. The town and region of Katherine are particularly impacted by such inequities and have the highest rates of homelessness in Australia, composed almost entirely of Aboriginal people who represent 51% of the total population of 24,000 people. The region is serviced by a 60-bed hospital, and a small cohort of frequent attenders (FAs) represent 11% of the Emergency Department (ED) case load. The vast majority of FAs are Aboriginal and have very high burdens of social inequity and homelessness. FAs are a challenge to efficient and effective use of resources for most hospitals around the world, and investment in programs to address underlying social and chronic health issues contributing to frequent attendance have been demonstrated to be effective. METHODS: These are the interim findings of a prospective cohort study using five sources of linked health and related data to evaluate a community-based case management pilot in a culturally competent framework to support frequent attenders to the Katherine Hospital ED. FAs were defined as people with six or more presentations in 12 preceding months. The intervention composed of a community-based case management program with a multi-agency service delivery addressing underlying vulnerabilities contributing to ED presentations. RESULTS: Among this predominantly Aboriginal cohort (91%), there were high rates of homelessness (64%), food insecurity (60%) and alcohol misuse (64%), limited access to transport, and complex comorbidities (average of 2.8 chronic conditions per client). Following intervention, there was a statistically significant reduction in ED presentations (IRR 0.77, 95% CI 0.69-0.85), increased engagement with primary health care (IRR 1.90, 95% CI 1.78-2.03), and ambulance utilisation (IRR 1.21, 95% CI 1.07-1.38). Reductions in hospital admissions (IRR 0.93, 95% CI 0.77-1.10) and aeromedical retrievals (IRR 0.67, 95% CI 0.35-1.20) were not statistically significant. CONCLUSIONS: This study demonstrates the short-term impacts of community-led case management extending beyond the hospital setting, to address causes of recurrent ED presentations among people with complex social and medical backgrounds. Improving engagement with primary care is a particularly important outcome given the national impetus to reduce preventable hospital admissions