Agriculture, the Environment and Rural Sociology in the South

Agricultural conservation research was revived by rural sociologists in the late 1970s and gained momentum during the 1980s. Most of this research was focused, however, on social and farm organizational factors affecting technology adoption and diffusion. Few studies included environmental factors such as soil characteristics, land physiography, and climate. This paper reviews rural sociologists\u27 recent attention to environmental factors. Next, it describes the ecological and agricultural variation among production regions in the South and overviews Southern producers\u27 participation in federal farm conservation programs. Finally, it prescribes three tasks for rural sociologists in the South to consider if they are to improve their participation in the agricultural conservation policy process. *This paper is adapted from the presidential address given at the annual meeting of the Southern Rural Sociological Association in Lexington, Kentucky, February 1992

Identification of drug resistance mutations in HIV from constraints on natural evolution

Human immunodeficiency virus (HIV) evolves with extraordinary rapidity. However, its evolution is constrained by interactions between mutations in its fitness landscape. Here we show that an Ising model describing these interactions, inferred from sequence data obtained prior to the use of antiretroviral drugs, can be used to identify clinically significant sites of resistance mutations. Successful predictions of the resistance sites indicate progress in the development of successful models of real viral evolution at the single residue level, and suggest that our approach may be applied to help design new therapies that are less prone to failure even where resistance data is not yet available.Comment: 5 pages, 3 figure

Ionized Gas Kinematics At High Resolution. II. Discovery Of A Double Infrared Cluster In II Zw 40

The nearby dwarf galaxy II Zw 40 hosts an intense starburst. At the center of the starburst is a bright compact radio and infrared source, thought to be a giant dense H II region containing approximate to 14,000 O stars. Radio continuum images suggest that the compact source is actually a collection of several smaller emission regions. We accordingly use the kinematics of the ionized gas to probe the structure of the radio-infrared emission region. With TEXES on the NASA-IRTF we measured the 10.5 mu m [S IV] emission line with effective spectral resolutions, including thermal broadening, of similar to 25 and similar to 3 km s(-1) and spatial resolution similar to 1 ''. The line profile shows two distinct, spatially coextensive, emission features. The stronger feature is at galactic velocity and has FWHM 47 km s(-1). The second feature is similar to 44 km s(-1) redward of the first and has FWHM 32 km s(-1). We argue that these are two giant embedded clusters, and estimate their masses to be approximate to 3 x 10(5) M-circle dot and approximate to 1.5 x 10(5) M-circle dot. The velocity shift is unexpectedly large for such a small spatial offset. We suggest that it may arise in a previously undetected kinematic feature remaining from the violent merger that formed the galaxy.University of Hawaii NNX-08AE38ANSF AST-0607312NASAAstronom

Structurally adaptive space crane concept for assembling space systems on orbit

Many future human space exploration missions will probably require large vehicles that must be assembled on orbit. Thus, a device that can move, position, and assemble large and massive spacecraft components on orbit becomes essential for these missions. A concept is described for such a device: a space crane concept that uses erectable truss hardware to achieve high-stiffness and low-mass booms and uses articulating truss joints that can be assembled on orbit. The hardware has been tested and shown to have linear load-deflection response and to be structurally predictable. The hardware also permits the crane to be reconfigured into different geometries to satisfy future assembly requirements. A number of articulating and rotary joint concepts have been sized and analyzed, and the results are discussed. Two strategies were proposed to suppress motion-induced vibration: placing viscous dampers in selected truss struts and preshaping motion commands. Preliminary analyses indicate that these techniques have the potential to greatly enhance structural damping

Direct and indirect selection on flowering time, water-use efficiency (WUE, δ (13)C), and WUE plasticity to drought in Arabidopsis thaliana.

Flowering time and water-use efficiency (WUE) are two ecological traits that are important for plant drought response. To understand the evolutionary significance of natural genetic variation in flowering time, WUE, and WUE plasticity to drought in Arabidopsis thaliana, we addressed the following questions: (1) How are ecophysiological traits genetically correlated within and between different soil moisture environments? (2) Does terminal drought select for early flowering and drought escape? (3) Is WUE plasticity to drought adaptive and/or costly? We measured a suite of ecophysiological and reproductive traits on 234 spring flowering accessions of A. thaliana grown in well-watered and season-ending soil drying treatments, and quantified patterns of genetic variation, correlation, and selection within each treatment. WUE and flowering time were consistently positively genetically correlated. WUE was correlated with WUE plasticity, but the direction changed between treatments. Selection generally favored early flowering and low WUE, with drought favoring earlier flowering significantly more than well-watered conditions. Selection for lower WUE was marginally stronger under drought. There were no net fitness costs of WUE plasticity. WUE plasticity (per se) was globally neutral, but locally favored under drought. Strong genetic correlation between WUE and flowering time may facilitate the evolution of drought escape, or constrain independent evolution of these traits. Terminal drought favored drought escape in these spring flowering accessions of A. thaliana. WUE plasticity may be favored over completely fixed development in environments with periodic drought

Concerns with AED conversion: comparison of patient and physician perspectives.

When discussing AED conversion in the clinic, both the patient and physician perspectives on the goals and risks of this change are important to consider. To identify patient-reported and clinician-perceived concerns, a panel of epilepsy specialists was questioned about the topics discussed with patients and the clinician's perspective of patient concerns. Findings of a literature review of articles that report patient-expressed concerns regarding their epilepsy and treatment were also reviewed. Results showed that the specialist panel appropriately identified patient-reported concerns of driving ability, medication cost, seizure control, and medication side effects. Additionally, patient-reported concerns of independence, employment issues, social stigma, medication dependence, and undesirable cognitive effects are important to address when considering and initiating AED conversion

A Social Exchange Explanation of Participation in the U.S. Farm Program

Passage of the 1990 Food, Agriculture, Conservation, and Trade Act resulted from the political influence of many environmental interest groups and, consequently, included many conservation provisions. As agricultural policy has increasingly reflected the environmental concerns of the public, farmers who participate in the Farm Program have adjusted their production practices to conserve land and water resources, minimize use of agrichemicals, and control animal wastes. Social exchange theory was used to examine personal and farm characteristics that could affect agroenvironmental attitudes, Farm Program participation, and conservation practices of Texas farmers (n = 1,063 farmers) in 199 1. One in four farmers did not participate in a federal commodity/conservation program. Less than 8 percent of the variation in regulatory and environmental attitudes was explained by personal and farm characteristics, compared to 30 percent of the variation in Farm Program participation and 14 percent in use of conservation practices. Agroenvironmental attitudes and most background characteristics were poor predictors of farm-related behaviors. Level of gross farm income was the best predictor of farmers\u27 attitudes and behaviors. Implications of these findings are discussed

Ne II Observations of Gas Motions in Compact and Ultracompact H II Regions

We present high spatial and spectral resolution observations of 16 Galactic compact and ultracompact H II regions in the [Ne II] 12.8 mu m fine-structure line. The small thermal width of the neon line and the high dynamic range of the maps provide an unprecedented view of the kinematics of compact and ultracompact H II regions. These observations solidify an emerging picture of the structure of ultracompact H II regions suggested in our earlier studies of G29.96-0.02 and Mon R2 IRS 1; systematic surface flows, rather than turbulence or bulk expansion, dominate the gas motions in the H II regions. The observations show that almost all of the sources have significant (5-20 km s(-1)) velocity gradients and that most of the sources are limb-brightened. In many cases, the velocity pattern implies tangential flow along a dense shell of ionized gas. None of the observed sources clearly fits into the categories of filled expanding spheres, expanding shells, filled blister flows, or cometary H II regions formed by rapidly moving stars. Instead, the kinematics and morphologies of most of the sources lead to a picture of H II regions confined to the edges of cavities created by stellar wind ram pressure and flowing along the cavity surfaces. In sources where the radio continuum and [Ne II] morphologies agree, the majority of the ionic emission is blueshifted relative to nearby molecular gas. This is consistent with sources lying on the near side of their natal clouds being less affected by extinction and with gas motions being predominantly outward, as is expected for pressure-driven flows.NSF AST-0607312, NSF-0708074SOFIA USRA8500-98-008NYSTAR Faculty Development ProgramNASA NNG 04-GG92G, CAN-NCC5-679Lunar and Planetary InstituteAstronom