14,582 research outputs found
Changing Farm Structure and the Distribution of Farm Payments and Federal Crop Insurance
The distribution of commodity-related payments and Federal crop insurance indemnities to U.S. farmers has shifted to larger farms as more and more U.S. agricultural production is done on those farms. Since the operators of larger farms tend to have higher household incomes than other farm operators, commodity-related program payments and Federal crop insurance indemnities also have shifted to higher income households. By 2009, half of commodity-related program payments went to farms operated by households earning over 209,000 and 10 percent went to farms operated by households with incomes of at least 12.3 billion in 2009. Total Federal crop insurance indemnity payments were $5.2 billion in 2009.farm program payments, Federal crop insurance, Agricultural Resource Management Survey, structural change, income caps, payment limits., Agricultural and Food Policy, Agricultural Finance, Industrial Organization, Public Economics,
Locally Optimally-emitting Clouds and the Narrow Emission Lines in Seyfert Galaxies
The narrow emission line spectra of active galactic nuclei are not accurately
described by simple photoionization models of single clouds. Recent Hubble
Space Telescope images of Seyfert 2 galaxies show that these objects are rich
with ionization cones, knots, filaments, and strands of ionized gas. Here we
extend to the narrow line region the ``locally optimally emitting cloud'' (LOC)
model, in which the observed spectra are predominantly determined by powerful
selection effects. We present a large grid of photoionization models covering a
wide range of physical conditions and show the optimal conditions for producing
many of the strongest emission lines. We show that the integrated narrow line
spectrum can be predicted by an integration of an ensemble of clouds, and we
present these results in the form of diagnostic line ratio diagrams making
comparisons with observations. We also predict key diagnostic line ratios as a
function of distance from the ionizing source, and compare these to
observations. The predicted radial dependence of the [O III]/[O II] ratio may
be matched to the observed one in NGC4151, if the narrow line clouds see a more
intense continuum than we see. The LOC scenario when coupled with a simple
Keplerian gravitational velocity field will quite naturally predict the
observed line width versus critical density relationship. The influence of dust
within the ionized portion of the clouds is discussed and we show that the more
neutral gas is likely to be dusty, although a high ionization dust-free region
is most likely present too. This argues for a variety of NLR cloud origins.Comment: 29 pages plus 16 figures, accepted for publication in Ap
Fibroblast Memory in Development, Homeostasis and Disease
Fibroblasts are the major cell population in the connective tissue of most organs, where they are essential for their structural integrity. They are best known for their role in remodelling the extracellular matrix, however more recently they have been recognised as a functionally highly diverse cell population that constantly responds and adapts to their environment. Biological memory is the process of a sustained altered cellular state and functions in response to a transient or persistent environmental stimulus. While it is well established that fibroblasts retain a memory of their anatomical location, how other environmental stimuli influence fibroblast behaviour and function is less clear. The ability of fibroblasts to respond and memorise different environmental stimuli is essential for tissue development and homeostasis and may become dysregulated in chronic disease conditions such as fibrosis and cancer. Here we summarise the four emerging key areas of fibroblast adaptation: positional, mechanical, inflammatory, and metabolic memory and highlight the underlying mechanisms and their implications in tissue homeostasis and disease
Older Emergency Department Drivers: Patterns, Behaviors, and Willingness to Enroll in a Safe Driver Program
Objective: Our objective was to assess the reported driving patterns of older emergency department (ED) drivers and the factors that might lead them to enroll in a safe driving program.Methods: We conducted a prospective, cross-sectional survey of a convenience sample of ED patients 65-years-old and up regarding their driving patterns, behaviors and willingness to enroll in a safe driving program.Results: We surveyed 138 patients. Most (73%) reported driving within the last year, and 88% of these believe they could not manage without driving. Eleven percent of ED older drivers have been in a motor vehicle crash (MVC) in the past year (95% CI 6-20%), compared to 2.5% of all seniors. Our survey findings suggest that 88% of older ED drivers avoid at least some high-risk driving situations and 65% are unwilling to enroll in a safe driver program unless it lowers their automobile insurance rates. At the same time, most older ED drivers underestimate their risk of being involved in (75%) or dying from (74%) a MVC.Conclusion: Overall, there are a significant number of older people for whom driving remains a vital yet risky daily function. Most of these drivers have little interest in information regarding safe driving programs while in the ED. Those willing to learn about such programs would prefer to take home the information regarding the program rather than have any staff member discuss it while in the ED. [West J Emerg Med. 2011;12(1):51-55.
Observation of lobes near the X-point in resonant magnetic perturbation experiments on MAST
The application of non-axisymmetric resonant magnetic perturbations (RMPs)
with a toroidal mode number n=6 in the MAST tokamak produces a significant
reduction in plasma energy loss associated with type-I Edge Localized Modes
(ELMs), the first such observation with n>3. During the ELM mitigated stage
clear lobe structures are observed in visible-light imaging of the X-point
region. These lobes or manifold structures, that were predicted previously,
have been observed for the first time in a range of discharges and their
appearance is correlated with the effect of RMPs on the plasma i.e. they only
appear above a threshold when a density pump out is observed or when the ELM
frequency is increased. They appear to be correlated with the RMPs penetrating
the plasma and may be important in explaining why the ELM frequency increases.
The number and location of the structures observed can be well described using
vacuum modelling. Differences in radial extent and poloidal width from vacuum
modelling are likely to be due to a combination of transport effects and plasma
screening.Comment: 15 pages, 5 figure
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