Economic analysis of animal disease control inputs at farm level: the case of trypanocide use in villages under risk of drug resistance in West Africa

This paper presents an economic analysis of the use of drugs (isometamidium and diminazene) in controlling African Animal Trypanosomosis (AAT), a serious disease of cattle and small ruminants in villages that exhibit resistance to isometamidium in Burkina Faso and Mali in West Africa. The study applies a production function framework integrating a damage control function to assess the short term productivity effect of trypanocide use under different epidemiological conditions. We found that the marginal value products of isometamidium in all epidemiological conditions, and the marginal value product of diminazene in high-prevalence-high-resistance conditions are positive and greater than one revealing an underuse of trypanocidal drugs in those conditions. The economical optimum level of isometamidium is far larger than the current use level. In a strict economic interpretation, this implies that in the short term cattle farmers could increase the profitability if they increase trypanocide input beyond current levels. On the other hand, if the use of trypanocide increases, cattle farmers will also be more likely to experience future losses from trypanocide resistance. In this paper we demonstrated the feasibility of applying the damage control framework for measuring the productivity of veterinary therapeutic drugs at farm level in poor African countries

Inverted Echo Sounder Telemetry System Report

From August 1989 until August 1990, a simple acoustic telemetry system was used for obtaining real-time data from 5 Inverted Echo Sounders (IESs) deployed in the SYNOP inlet array in the Gulf Stream east of Cape Hatteras. Every 24 hours, each IES calculated a representative travel time from a set of 48 measurements (τ), and telemetered that value to a listening station on Bermuda. From the received data, a daily time series of the depth of the 12oC isotherm (our proxy for main thermocline depth) over each IES was calculated. The position of the Gulf Stream North Wall through the IES array was calculated on a daily basis from the thermocline depth information at each IES site. The telemetry system is based on encoding data as a time delayed broadcast acoustic signal: the delay of the time of broadcast of the signal, with with respect to a reference time, is proportional to the data value. The changes in delay time, from one broadcast signal to the next, are recorded at a remote receiving station. The IESs were recovered in August 1990, with the exception of the one at site B2. The telemetered data from the IES at site B2 was, however received at Bermuda. The RMS agreement between thermocline depths, as calculated from the data on tape from the recovered IESs and as calculated from the received telemetry data, is 20 m. This compares favorably with the 19 m uncertainty in calibrating the τs as a measure of the thermocline depth. The RMS agreement between the position of the Gulf Stream path through the IESs as calculated from the tape data and the telemetry data is 5 km. This telemetry system is not IES specific. It could be used with other appropriately modified oceanographic instruments, such as current meters and pressure sensors

Improving the precision of dynamic forest parameter estimates using Landsat

The use of satellite-derived classification maps to improve post-stratified forest parameter estimates is well established.When reducing the variance of post-stratification estimates for forest change parameters such as forest growth, it is logical to use a change-related strata map. At the stand level, a time series of Landsat images is ideally suited for producing such a map. In this study, we generate strata maps based on trajectories of Landsat Thematic Mapper-based normalized difference vegetation index values, with a focus on post-disturbance recovery and recent measurements. These trajectories, from1985 to 2010, are converted to harmonic regression coefficient estimates and classified according to a hierarchical clustering algorithm from a training sample. The resulting strata maps are then used in conjunction with measured plots to estimate forest status and change parameters in an Alabama, USA study area. These estimates and the variance of the estimates are then used to calculate the estimated relative efficiencies of the post-stratified estimates. Estimated relative efficiencies around or above 1.2 were observed for total growth, total mortality, and total removals, with different strata maps being more effective for each. Possible avenues for improvement of the approach include the following: (1) enlarging the study area and (2) using the Landsat images closest to the time of measurement for each plot. Multitemporal satellite-derived strata maps show promise for improving the precision of change parameter estimates

Improving the precision of dynamic forest parameter estimates using Landsat

The use of satellite-derived classification maps to improve post-stratified forest parameter estimates is well established.When reducing the variance of post-stratification estimates for forest change parameters such as forest growth, it is logical to use a change-related strata map. At the stand level, a time series of Landsat images is ideally suited for producing such a map. In this study, we generate strata maps based on trajectories of Landsat Thematic Mapper-based normalized difference vegetation index values, with a focus on post-disturbance recovery and recent measurements. These trajectories, from1985 to 2010, are converted to harmonic regression coefficient estimates and classified according to a hierarchical clustering algorithm from a training sample. The resulting strata maps are then used in conjunction with measured plots to estimate forest status and change parameters in an Alabama, USA study area. These estimates and the variance of the estimates are then used to calculate the estimated relative efficiencies of the post-stratified estimates. Estimated relative efficiencies around or above 1.2 were observed for total growth, total mortality, and total removals, with different strata maps being more effective for each. Possible avenues for improvement of the approach include the following: (1) enlarging the study area and (2) using the Landsat images closest to the time of measurement for each plot. Multitemporal satellite-derived strata maps show promise for improving the precision of change parameter estimates

Etude des politiques relatives aux stratégies de gestion de la chimiorésistance dans le cadre de la lutte contre la trypanosomose en Afrique de l'Ouest: cas du Mali

Discussion sur l’etude des politiques relatives aux stratégies de gestion de la chimiorésistance dans le cadre de la lutte contre la trypanosomose en Afrique de l’Ouest, Mali. Le projet a pour objectif d’assurer l’efficacité des trypanocides comme une composante effective des strategies intégrées et améliorées de contrôle de Ia trypanosomose animale dans Ia region ouest-africaine. Pour atteindre cet objectif, des organisations nationales de recherche et de developpement, des institutions internationales et régionales de recherche, et des universités allemandes travaillent en partenariat afin de développer aux niveaux local et regional des strategies de reduction de risque de Ia chimiorésistance. L’accent est mis principalement sur l‘information et des supports techniques aux paysans, aux prestataires de service en sante animale, aux vétérinaires professionnels et aux décideurs politiques. Les informations et supports techniques ont pour but de promouvoir Ia lutte intégrée et l’utilisation rationnelle des trypanocides afin de réduire les risques a long terme de Ia chimiorésistance sans compromettre Ia capacité des éleveurs a pouvoir protéger leurs animaux contre les effets néfastes de la trypanosomose animale. Le projet est réalisé au Burkina Faso, au Mali et en Guinée par l’lnstitut International de Recherche sur l’Elevage (lLRl) en collaboration avec d’autres organisations. Des approaches de solutions sont alors proposees de maniere a apporter une solution durable au phenomene de la chimioresistance

Life and Operating Range Extension of the BPT-4000 Qualification Model Hall Thruster

Following completion of the 5,600 hr qualification life test of the BPT-4000 4.5 kW Hall Thruster Propulsion System, NASA and Aerojet have undertaken efforts to extend the qualified operating range and lifetime of the thruster to support a wider range of NASA missions. The system was originally designed for orbit raising and stationkeeping applications on military and commercial geostationary satellites. As such, it was designed to operate over a range of power levels from 3 to 4.5 kW. Studies of robotic exploration applications have shown that the cost savings provided by utilizing commercial technology that can operate over a wider range of power levels provides significant mission benefits. The testing reported on here shows that the 4.5 kW thruster as designed has the capability to operate efficiently down to power levels as low as 1 kW. At the time of writing, the BPT-4000 qualification thruster and cathode have accumulated over 400 hr of operation between 1 to 2 kW with an additional 600 hr currently planned. The thruster has demonstrated no issues with longer duration operation at low power

Extent of Left Ventricular Scar Predicts Outcomes in Ischemic Cardiomyopathy Patients With Significantly Reduced Systolic Function A Delayed Hyperenhancement Cardiac Magnetic Resonance Study

ObjectivesThe objective of the study was to determine whether the extent of left ventricular scar, measured with delayed hyperenhancement cardiac magnetic resonance (DHE-CMR), predicts survival in patients with ischemic cardiomyopathy (ICM) and severely reduced left ventricular ejection fraction (LVEF).BackgroundPatients with ICM and reduced LVEF have poor survival. Such patients have a high myocardial scar burden. CMR is highly accurate in delineation of myocardial scar.MethodsWe studied 349 patients (76% men) with severe ICM (≥70% disease in ≥1 epicardial coronary, and mean LVEF of 24%) that underwent DHE-CMR (Siemens 1.5-T scanner, Erlangen, Germany), between 2003 and 2006. Scar (quantified as percentage of myocardium) was defined on DHE-MR images as an intensity >2 standard deviations above the viable myocardium. Transmurality score was semiquantitatively recorded in a 17-segment model as: 0 = no scar, 1 = 1% to 25% scar, 2 = 26% to 50%, 3 = 51% to 75%, and 4 = >75%. The LVEF, demographic data, risk factors, need for cardiac transplantation (CTx), and all-cause mortality were recorded.ResultsThe mean age and follow-up were 65 ± 11 years and 2.6 ± 1.2 years (median 2.4 years [1.1, 3.5]), respectively. There were 56 events (51 deaths and 5 CTx). Mean scar percentage and transmurality score were higher in patients with events versus those without (39 ± 22 vs. 30 ± 20, p = 0.003, and 9.7 ± 5 vs. 7.8 ± 5, p = 0.004). On Cox proportional hazard survival analysis, quantified scar was greater than the median (30% of total myocardium), and female gender predicted events (relative risk 1.75 [95% Confidence Interval: 1.02 to 3.03] and relative risk 1.83 [95% Confidence Interval: 1.06 to 3.16], respectively, both p = 0.03).ConclusionsIn patients with ICM and severely reduced LVEF, a greater extent of myocardial scar, delineated by DHE-CMR is associated with increased mortality or the need for cardiac transplantation, potentially aiding further risk-stratification