Application of moderate resolution band models to the prediction of heat transfer from rocket exhaust plumes

Computer program for resolution band model prediction of heat transfer from rocket exhaust plume

New technique to measure the cavity defects of Fabry-Perot interferometers

(Abridged): We define and test a new technique to accurately measure the cavity defects of air-spaced FPIs, including distortions due to the spectral tuning process typical of astronomical observations. We further develop a correction technique to maintain the shape of the cavity as constant as possible during the spectral scan. These are necessary steps to optimize the spectral transmission profile of a two-dimensional spectrograph using one or more FPIs. We devise a generalization of the techniques developed for the so-called phase-shifting interferometry to the case of FPIs. The technique is applicable to any FPI that can be tuned via changing the cavity spacing ($z$-axis), and can be used for any etalon regardless of the coating' reflectivity. The major strength of our method is the ability to fully characterize the cavity during a spectral scan, allowing for the determination of scan-dependent modifications of the plates. As a test, we have applied this technique to three 50 mm diameter interferometers, with cavity gaps ranging between 600 micron and 3 mm, coated for use in the visible range. We obtain accurate and reliable measures of the cavity defects of air-spaced FPIs, and of their evolution during the entire spectral scan. Our main, and unexpected, result is that the relative tilt between the two FPI plates varies significantly during the spectral scan, and can dominate the cavity defects; in particular, we observe that the tilt component at the extremes of the scan is sensibly larger than at the center of the scan. Exploiting the capability of the electronic controllers to set the reference plane at any given spectral step, we develop a correction technique that allows the minimization of the tilt during a complete spectral scan. The correction remains highly stable over long periods, well beyond the typical duration of astronomical observations.Comment: 15 pages, 20+ figures, accepted for publication in A&A. Two additional movies are available in the online version of the pape

Impacts of Agrifood Market Transformation during Globalization on the Poor's Rural Nonfarm Employment: Lessons for Rural Business Development Programs

Consumer/Household Economics, Resource /Energy Economics and Policy,

Impacts of Agrifood Market Transformation during Globalization on the Poor's Rural Nonfarm Employment: Lessons for Rural Business Development Programs

This paper presents emerging evidence pointing to the transmission to developing countries' rural spaces of the impacts of agrifood market transformation occurring at national and global levels. That transmission takes place via retail chains penetrating intermediate cities and rural towns, and urban-based food manufacturers selling products to those chains as well as to traditional shops. The paper presents and justifies three main hypotheses concerning the impacts of that penetration. (1) The direct effect is that the modern retailers and modern-sector processed products directly compete with, and present potentially major challenges to, the processed foods, farm inputs, and commercial services already being undertaken in the RNFE sector by the rural poor among others. (2) The indirect effects is that modern sector firms tend, once they have "modernized" their procurement systems, to prefer larger suppliers if available, and/or small suppliers that have the requisite levels of capital assets. This further translates to a potential labor substitution bias, in particular of unskilled labor, although it may drive skilled labor demand. (3) The production and consumption linkage effects of the above impacts on RNFE firms, laborers, and farmers, all else equal, probably implies greater demand for non-tradeable goods and services in the RNFE that correspond to the demand patterns of the upper stratum of rural consumers. Faced with the above, what can business development programs do? (1) Given the change in the market context, it will be increasingly undesirable and "un-strategic," except in the most remote, hinterland areas, to maintain the separation between competitiveness and nonfarm employment programs. At least for RNF activities that supply processed products, farm inputs, and retail commerce, RNF enterprises will need to face the same general challenge that exporters in their country face on the global market, and urban firms face, which is to compete on cost and quality. (2) Second, maintaining the analogy to international competitiveness, it will be necessary go beyond a generic competitiveness approach, to employ a "customized competitiveness" strategy (a term used by Reardon and Flores 2006 for export programs, but applicable here). Such an approach focuses on understanding the specific requirements of transformed markets and building the capacity of particular groups to respond to those requirements (as suppliers) or match cost and quality and compete for specific niches. The capital assets that programs should building include market intelligence capital, organizational capital, technology capital, and financial (and risk reduction) capital. (3) In the economic transformation, this time in the rural space, the poorest, those with least assets, are again vulnerable. Special attention should be paid to equipping those households and firms to participate in the increasingly challenging rural nonfarm economy.Community/Rural/Urban Development,

Statistical Analysis of Small Ellerman Bomb Events

The properties of Ellerman bombs (EBs), small-scale brightenings in the H-alpha line wings, have proved difficult to establish due to their size being close to the spatial resolution of even the most advanced telescopes. Here, we aim to infer the size and lifetime of EBs using high-resolution data of an emerging active region collected using the Interferometric BIdimensional Spectrometer (IBIS) and Rapid Oscillations of the Solar Atmosphere (ROSA) instruments as well as the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO). We develop an algorithm to track EBs through their evolution, finding that EBs can often be much smaller (around 0.3") and shorter lived (less than 1 minute) than previous estimates. A correlation between G-band magnetic bright points and EBs is also found. Combining SDO/HMI and G-band data gives a good proxy of the polarity for the vertical magnetic field. It is found that EBs often occur both over regions of opposite polarity flux and strong unipolar fields, possibly hinting at magnetic reconnection as a driver of these events.The energetics of EB events is found to follow a power-law distribution in the range of "nano-flare" (10^{22-25} ergs).Comment: 19 pages. 7 Figure

Where are we short and who are we short of? A review of the human resources for health in South Africa

This review showed that thinking about the shortage of health care personnel merely in terms of insufficient numbers prevents sound strategic interventions to solve the country’s human resources for health (HRH) problem. It revealed that the numbers shortage was one facet of a broader problem that included the mal distribution of HRH, production of the wrong skills in the nursing care, the attrition of staff from the public health services and, contextually, the ever-changing demands on the health services. The challenge in South Africa was furthermore to train and retain health care personnel with skills and expertise that are commensurate with the changing demands on the public health services.Uit hierdie oorsig het dit duidelik geblyk dat die tekort van gesondheidsorgpersoneel slegs in terme van ontoereikende getalle val en ’n omvattende strategiese ingryping om die land se menslike gesondheidshulpbron krisis op te los, belemmer. Dit het aangedui dat die getalletekort maar slegs een fasset van ’n groter probleem uitmaak, wat onder andere die volgende insluit: die oneweredige verspeiding van menslike gesondheidshulpbronne, ’n fokus op ontoepaslike vaardighede in die opleiding van verpleegpersoneel, die behoud van personeel in die openbare gesondheidsektor, asook die konstant-veranderlike eise van die gesondheidsdienste. Verder was die uitdaging in Suid Afrika die opleiding en behoud van gesondheidsorgpersoneel met kennis en vaardighede wat tred hou met die veranderlike eise van die openbare gesondheidsdienste

Opciones para el desarrollo del empleo rural no agrícola en América Latina y el Caribe

El empleo y el ingreso rurales no agrícolas constituyen una vía muy importante de salida de la pobreza, para muchos hogares e individuos rurales que carecen de los recursos necesarios para intentar otras opciones de progreso, como puede ser la emigración o el trabajo agrícola por cuenta propia. El documento presenta una visión de estas actividades rurales no agrícolas como elementos deseables de una sociedad rural moderna, lo que contrasta con los esquemas que ven en la caída del empleo agrícola una manifestación de progreso económico. El trabajo describe las características, los tipos y la importancia y potencialidades del empleo y del ingreso rurales no agrícolas en varios países de la región; y presenta recomendaciones para el desarrollo de estrategias de fomento del empleo y del ingreso rurales no agrícolas, incluyendo el diseño de políticas públicas orientadas a aumentar las opciones para el desarrollo de las economías rurales de la región.Agronegocio, Política agrícola, Desarrollo rural, empleo rural no agrícola, ingreso rural no agrícola, América Latina, erna, irna