3,660 research outputs found
Considerations in the Dairy Relocation Decision
Historically, U.S. dairymen have been thought to move to a new location to seek better economic opportunities or to leave an area that has become disadvantaged due to regulation or economics. Recently, there again have been major shifts in dairy production across the United States.Livestock Production/Industries,
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Disclosure Standards and the Sensitivity of Returns to Mood
We provide evidence that higher-quality disclosure standards are associated with stock returns that are less sensitive to noise driven by investors\u27 moods. We identify return-mood sensitivity (RMS) based on the association between index returns and urban cloudiness, a source of short-term variation in mood. Based on a stylized model, we predict and find evidence consistent with higher-quality disclosure standards reducing RMS by tilting susceptible investors\u27 trades toward information and by facilitating sophisticated investors\u27 arbitrage. Our findings suggest that disclosure standards play an important role in enhancing price efficiency by reducing noise in returns, particularly noise related to investors\u27 short-term moods
A search for Lyman Break Galaxies at z>8 in the NICMOS Parallel Imaging Survey
We have selected 14 J-dropout Lyman Break Galaxy (LBG) candidates with J110 -
H160 > 2.5 from the NICMOS Parallel Imaging Survey. This survey consists of 135
square arcminutes of imaging in 228 independent sight lines, reaching average 5
sigma sensitivities of J110 = 25.8 and H160 = 25.6 (AB). Distinguishing these
candidates from dust reddened star forming galaxies at z ~ 2-3 is difficult,
and will require longer wavelength observations. We consider the likelihood
that any J-dropout LBGs exist in this survey, and find that if L*(z=9.5) is
significantly brighter than L*(z=6) (a factor of four), then a few J-dropout
LBGs are likely. A similar increase in luminosity has been suggested by Eyles
et al. and Yan et al., but the magnitude of this increase is uncertain.Comment: Accepted to ApJ Letter
Representative Farms Economic Outlook for the December 2007 FAPRI/AFPC Baseline
The farm level economic impacts of the Farm Security and Rural Investment Act of 2002 (2002 Farm Bill) on representative crop, dairy, and livestock operations are projected in this report. The analysis was conducted over the 2007-2012 planning horizon using FLIPSIM, AFPCâs whole farm simulation model. Data to simulate agricultural operations in the nationâs major production regions came from two sources: âą Producer panel cooperation to develop economic information to describe and simulate representative crop, livestock, and dairy farms. âą Projected prices, policy variables, and input inflation rates from the Food and Agricultural Policy Research Institute (FAPRI) December 2007 Baseline. The FLIPSIM policy simulation model incorporates the historical risk faced by agricultural producers for prices and production. This report presents the results of the December 2007 Baseline in a risk context using selected simulated probabilities and ranges for annual net cash farm income values. The probability of a farm experiencing a negative ending cash balance and the probability of a farm losing real net worth are included as indicators of the cash flow and equity risks facing producers through the year 2012. This report is organized into ten sections. The first section summarizes the process used to develop the representative farms and the key assumptions utilized for the farm level analysis. The second section summarizes the FAPRI December 2007 Baseline and the policy and price assumptions used for the representative farm analyses. The third through sixth sections present the results of the simulation analyses for feed grain, wheat, cotton, and rice farms. The seventh and eighth sections summarize simulation results for dairy and cattle. Two appendices constitute the final sections of the report. Appendix A provides tables to summarize the physical and financial characteristics for each of the representative farms. Appendix B provides the names of producers, land grant faculty, and industry leaders who cooperated in the panel interview process to develop the representative farms.
Response of deep-sea deposit-feeders to detrital inputs: A comparison of two abyssal time-series sites
Biological communities on the abyssal plain are largely dependent on detritus from the surface ocean as their main source of energy. Seasonal fluctuations in the deposition of that detritus cause temporal variations in the quantity and quality of food available to these communities, altering their structure and the activity of the taxa present. However, direct observations of energy acquisition in relation to detritus availability across megafaunal taxa in abyssal communities are few. We used time-lapse photography and coincident measurement of organic matter flux from water column sediment traps to examine the impact of seasonal detrital inputs on resource acquisition by the deposit feeding megafauna assemblages at two sites: Station M (Northeast Pacific, 4000âŻm water depth) and the Porcupine Abyssal Plain Sustained Observatory (PAP-SO, Northeast Atlantic 4850âŻm water depth). At Station M, studied over 18-months, the seasonal particle flux was followed by a salp deposition event. At that site, diversity in types of deposit feeding was related to seabed cover by detritus. At PAP-SO, studied over 30 months, the seasonal particle flux consisted of two peaks annually. While the two study sites were similar in mean flux (~8.0 mgC mâ2 dâ1), the seasonality in the flux was greater at PAP-SO. The mean overall tracking at PAP-SO was five times that of Station M (1.9 and 0.4 cm2âŻhâ1, respectively); both are likely underestimated because tracking by some common taxa at both sites could not be quantified. At both sites, responses of deposit-feeding megafauna to the input of detritus were not consistent across the taxa studied. The numerically-dominant megafauna (e.g. echinoids, large holothurians and asteroids) did not alter their deposit feeding in relation to the seasonality in detrital supply. Taxa for which deposit feeding occurrence or rate were correlated to seasonality in particle flux were relatively uncommon (e.g. enteropneusta), known to cache food (e.g. echiurans), or to be highly selective for fresh detritus (e.g. the holothurian Oneirophanta mutabilis). Thus, the degree of seasonality in deposit feeding appeared to be taxon-specific and related to natural history characteristics such as feeding and foraging modes
Inter-annual species-level variations in an abyssal polychaete assemblage (Sta. M, NE Pacific, 4000 m)
Understanding the dynamics of abyssal community structure and function has become increasingly important as deep-sea resource exploitation and climate change pressures are expected to ramp up. This time-series study investigates macrofaunal polychaete dynamics at a station in the North East Pacific (Sta. M; 35Ë N 123Ë W, 4000 m, 1991-2011). Infaunal polychaete species were identified and their proxy biomass and proxy energy use rate estimated. The assemblage comprised 167 species, having a composition consistent with other abyssal areas globally. Significant changes in univariate and multivariate parameters (rank abundance distribution, Simpsonâs diversity index, and species and functional group composition) were detected across 1991-2011. However, no change in biomass or energy use rate was apparent through the time-series. The largest changes in the polychaete assemblage coincided with both an increase in sinking particulate organic carbon flux to the seafloor in 2007, and a 40 km relocation of the sampling location to a site 100 m shallower, preventing a conclusive assessment of which might drive the observed variation. Analyses prior to the change of sampling location showed that the polychaete assemblage composition dynamics were primary driven by food supply variation. Changes in several species were also lagged to changes in POC flux by 4 to 10 months. The polychaete fauna exhibited a significant positive relationship between total density and total energy use rate, suggesting population-level tracking of a common resource (e.g. POC flux food supply). Neither compensatory nor energetic zero-sum dynamics were detected among the polychaete assemblage, but the results suggest that the latter occur in the macrofaunal community as a whole. The results do indicate (a) potential control of species composition, and the density of individual key species, by food supply, when the time-series prior to the sampling location was analysed separately, and (b) generally sensitive detection of environmental change by species-level analysis of the abyssal polychaete assemblage
Germination of Silene regia Seeds from Four Sites in Lawrence County, Illinois, Following Scarification or Stratification
Silene regia Sims is an endangered prairie forb in Illinois where small isolated colonies are scattered. In La·wrence County, two sites (Allison Prairie and Chauncey Marsh) have fewer plants (6-23) than two other sites (Cmmty Road and Cemetery) with 26-45 plants. Information on seed germination in these isolated colonies is needed. Our goal was to evaluate seed germination of S. regia from colonies in Lawrence County, illinois. S. regia fruits were collected from these four sites on August 9 and 19, 1999. Seeds were scarified by cutting the seed coat, or they were stratified at 2 C for 12 or 15 weeks. Seeds from Chaun.cey Marsh weighed less than those from other sites. With the exception of seeds from Chauncey Marsh, scariiication increased gemrination within each site. When significant germination differences occurred due to site, they were apparent on stratified seed, where frequently Allison Prairie was highest and Chauncey Marsh was lowest. Germination clifferences between stratified and control seeds were inconsistent, although stratified seeds had up to 67% higher gemrination than control seeds when significant differences occurred. These increases in seed germination were most evident in seeds collected on August 9th and stratified for 12 weeks. Seed that was neither scarified nor stratified gemrinated after storage, indicating that scarification and stratification are not absolute gemrination requirements with after-ripened seeds. Seed germination at different sites did not correspond directly with population sizes, and multiple mechanisms were present for breaking seed donnancy in S. regia
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