LINKING LAND QUALITY, AGRICULTURAL PRODUCTIVITY, AND FOOD SECURITY

Land quality and land degradation affect agricultural productivity, but quantifying these relationships has been difficult. Data are limited, and impacts are sensitive to the choices that farmers make. Summarizing new research by economists, soil scientists, and geographers, this report explores the extent to which land quality and land degradation affect agricultural productivity, how farmers' responses to land degradation are influenced by economic, environmental, and institutional factors, and whether land degradation poses a threat to productivity growth and food security. Results suggest that land degradation does not threaten food security at the global scale, but does pose problems in areas where soils are fragile, property rights are insecure, and farmers have limited access to information and markets.Land quality, land degradation, soil erosion, agricultural productivity, food security, Food Security and Poverty, Land Economics/Use, Productivity Analysis,

LAND QUALITY, AGRICULTURAL PRODUCTIVITY, AND FOOD SECURITY AT LOCAL, REGIONAL, AND GLOBAL SCALES

Econometric and simulation analyses indicate that land degradation does not threaten agricultural productivity growth and food security at the global level, but problems exist in some areas. Improving market performance could reduce erosion-induced yield losses to 0.1 percent per year and the number of hungry people in less-developed countries by 5 percent over 10 years.land quality, agricultural productivity, food security, Food Security and Poverty, Productivity Analysis,

A Non-Zeeman Interpretation for Polarized Maser Radiation and the Magnetic Field at the Atmospheres of Late-Type Giants

The linear polarization that is observed, together with likely changes in the orientation of the magnetic field along the line of sight and hence of the optical axes of the medium, can lead to the circular polarization that is observed in the radiation of the circumstellar SiO masers. A magnetic field greater than only about 30 mG is required, in contrast to 10-100 G that would be implied by the Zeeman interpretation. To assess quantitatively the likely changes in orientation of the magnetic field, calculations are performed with representative field configurations that are created by statistical sampling using a Kolmogorov-like power spectrum.Comment: 7 pages Latex (aaspp4.sty), 3 ps-figures. Accepted for publication in Astrophysical Journal Letter

Do we need to know the temperature in prestellar cores?

Molecular line observations of starless (prestellar) cores combined with a chemical evolution modeling and radiative transfer calculations are a powerful tool to study the earliest stages of star formation. However, conclusions drawn from such a modeling may noticeably depend on the assumed thermal structure of the cores. The assumption of isothermality, which may work well in chemo-dynamical studies, becomes a critical factor in molecular line formation simulations. We argue that even small temperature variations, which are likely to exist in starless cores, can have a non-negligible effect on the interpretation of molecular line data and derived core properties. In particular, ``chemically pristine'' isothermal cores (low depletion) can have centrally peaked C$^{18}$O and C$^{34}$S radial intensity profiles, while having ring-like intensity distributions in models with a colder center and/or warmer envelope assuming the same underlying chemical structure. Therefore, derived molecular abundances based on oversimplified thermal models may lead to a mis-interpretation of the line data.Comment: ApJL, accepte

Spectra of Maser Radiation from a Turbulent, Circumnuclear Accretion Disk. III. Circular polarization

Calculations are performed for the circular polarization of maser radiation from a turbulent, Keplerian disk that is intended to represent the sub-parsec disk at the nucleus of the galaxy NGC4258. The polarization in the calculations is a result of the Zeeman effect in the regime in which the Zeeman splitting is much less than the spectral linebreadth. Plausible configurations for turbulent magnetic and velocity fields in the disk are created by statistical methods. This turbulence, along with the Keplerian velocity gradients and the blending of the three hyperfine components to form the $6_{16} - 5_{23}$ masing transition of water, are key ingredients in determining the appearance of the polarized spectra that are calculated. These spectra are quite different from the polarized spectra that would be expected for a two-level transition where there is no hyperfine structure. The effect of the hyperfine structure on the polarization is most striking in the calculations for the maser emission that represents the central (or systemic) features of NGC4258. Information about magnetic fields is inferred from observations for polarized maser radiation and bears on the structure of accretion disks.Comment: Latex, uses aastex, eucal, to be published in the Astrophysical Journa

RESOURCE QUALITY, AGRICULTURAL PRODUCTIVITY, AND FOOD SECURITY

USDA's Economic Research Service estimates that about 33 percent of the developing world's people suffer from insufficient food intake. Growth in agricultural productivity is critical to improvements in food security. We will examine the impact of changes in acreage and fertilizer response on production in 67 study countries and review the implications for food security.Food Consumption/Nutrition/Food Safety, Productivity Analysis,

Tarian Perdamaian: Enacting Alternative Hindu/Christian Identity Discourses Through Secular Balinese Performing Arts

This article examines the nature of interreligious relations between Protestants of the Bali Church and Hindus as enacted through dramatic forms of Balinese music and dance. Particular attention is paid to the influence of mass tourism as a contributing factor in this process. Since the early twentieth century these arts have formed a central component of a pan-Balinese identity discourse known as kebalian. The first Balinese converted to Christianity during the 1930s and were subsequently excommunicated from their ancestral villages for refusing to participate in local customary practices (including the ritualistic use of gamelan music). For this reason, Balinese Christians have historically been regarded as “traitors” with no claim to kebalian. Since the 1970s, however, the Bali Church has employed local music and dance in a variety of church-based contexts as one means to “contextualize” congregational life. The adoption of these and other forms of local culture (ex. language, clothing) have reconfigured and challenged the existing parameters of a generally Hindu-centric kebalian. This has led to the formation of a religion(agama)/culture(budaya) dichotomy, which is often used as the intellectual underpinning for the arts as a tool of identity construction. The article concludes with an analysis of the contextualized musical drama, Tarian Perdamaian, to illustrate the practical complications of this dichotomy and suggests the theatrically situated “interreligious gaze” as a lens through which to better understand the parameters of twenty-first century interreligious relations in Bali