The effect of thermal vibrations on extended x-ray absorption fine structure. I

The form of the Debye–Waller factor in EXAFS is discussed in detail, and an expression is obtained for this factor in a general three‐atom system of C_s symmetry. The normal modes which contribute to the Debye–Waller factors for each scattering path are dependent on the symmetry of the system. A series of model three‐atom systems with C_(2v) symmetry are studied and the Debye–Waller factors as a function of the bridging angle are discussed for each of these systems. The temperature dependence of the Debye‐Waller factor for each scattering path is also studied. In a system of C_(2v) symmetry, approximating the double and triple scattering Debye–Waller factors by the second shell single scattering factor is shown to be strictly valid only for a system close to linearity. The error due to this approximation is dependent upon the amplitude of the individual scattering paths and is shown to increase with temperature. When the single scattering contribution is unimportant, there is shown to exist a temperature where the above approximation is exact

The Political Economy of Increasing Block Tariffs for Water in Developing Countries

Increasing block tariffs (IBTs) have become the tariff structure of choice in developing countries. Multilateral donors, international financial and engineering consultants, and water sector professionals working in developing countries all commonly presume that IBT structures are the most appropriate way to determine water users' monthly bills. Most, if not all recent water tariff studies performed for developing countries propose IBT structures. The objective of this paper is to critically examine the current fashion of using IBTs in cities in developing countries. In the second section of the paper, we review the common arguments made to justify the adoption of IBTs, and present some actual IBTs currently in use in selected cities. In the third section of the paper we discuss the objectives and considerations involved in water tariff design so as to provide a basis for judging the appropriateness of IBTs.Tariff

Data analysis in extended x-ray-absorption fine structure: Determination of the background absorption and the threshold energy

Two approaches for the determination of the background absorption (μ_0) in the extended x-ray-absorption fine structure (EXAFS) are presented. Both methods, experimental and computational, take advantage of the damping of the EXAFS amplitude resulting from the convolution with Gaussian functions of different widths. In the experimental method two or more spectra are collected with the use of different spectrometer slit widths, resulting in spectra of different resolutions for the same sample. In the computational approach the convolution is accomplished via a convolution algorithm. The intersection points of the resulting spectra are used to generate μ_0. At the absorption edge, the spectra intersect at a unique point, which is shown to be a measure of the threshold energy, E_0. Illustration of the two methods for background removal is given for a copper-foil sample. The computational approach is superior to the experimental method of damping the EXAFS spectra to give μ_0

An Analysis of the 2002 Farm Bill’s Value-Added Producer Grants Program

Our objective is to identify the determinants for success among USDA’s Value- Added Producer Grants (VAPG) program recipients. Business development has become an important program in departments of agricultural economics. Market share was found to be an important determinant of VAPG success. Size variables including greater sales and increased grant dollars, as well as a lower number of producers, were also determinants of business success. Departments of agricultural economics are likely best able to assist VAPG recipients by providing information on price discovery, explaining their relationship to potential plant location, and providing education on best management practices to help producers avoid costly mistakes.agribusiness, business development, value-added, Agribusiness, Financial Economics, Productivity Analysis,

Grass-Fed Certification: The Case of the Uruguayan Beef Industry

International Relations/Trade, Livestock Production/Industries, Q13, Q17,

Astroturf, Technology and the Future of Community Mobilization: Implications for Nonprofit Theory

Nonprofit Organizations advocate for the poor, the disenfranchised and the oppressed. This process is thought to build social capital and civil society, while engendering the development of social skills and deliberation. In recent years, scholars have observed that nonprofit advocacy organizations have moved from membership associations to professionalized policy change organizations. Virtual advocacy will move the process farther afield. Astroturf, the creation of synthetic advocacy efforts, continues this process further. All of this has troubling implications for nonprofit organizations and nonprofit theory. This paper describes the astroturf phenomenon, reviews pertinent nonprofit theory and speculates on the impact of astroturf for society and the further development of nonprofit theory

Design and Evaluation of a Probabilistic Music Projection Interface

We describe the design and evaluation of a probabilistic interface for music exploration and casual playlist generation. Predicted subjective features, such as mood and genre, inferred from low-level audio features create a 34- dimensional feature space. We use a nonlinear dimensionality reduction algorithm to create 2D music maps of tracks, and augment these with visualisations of probabilistic mappings of selected features and their uncertainty. We evaluated the system in a longitudinal trial in users’ homes over several weeks. Users said they had fun with the interface and liked the casual nature of the playlist generation. Users preferred to generate playlists from a local neighbourhood of the map, rather than from a trajectory, using neighbourhood selection more than three times more often than path selection. Probabilistic highlighting of subjective features led to more focused exploration in mouse activity logs, and 6 of 8 users said they preferred the probabilistic highlighting mode