586 research outputs found
Infrared molecular emissions from comets
The possibility of detecting IR molecular line emission from cometary parent molecules is explored. Due to the non-LTE conditions in the inner coma and the large amount of near IR solar flux, IR fluorescence will be a significant source of cometary emission and, in fact, will dominate the grain radiation in a sufficiently high resolution instrument. The detection of this line emission will be difficult due to absorption in the terrestrial atmosphere, but it appears possible to measure cometary H2O emission from airplane altitudes. As IR molecular line emission represents one of the few promising methods of detecting cometary parent molecules directly, further research on this problem should be vigorously pursued
SOYBEANS QUALITY PRICE DIFFERENTIALS FROM AN ELEVATOR'S PERSPECTIVE
Soybean prices are determined by interaction between various factors. At an elevator, discount prices for unique characteristics can range from 0.02 cents per bushel to 7.71 cents per bushel of soybeans. This variation suggests that producers of soybeans need quality-characteristic specific information concerning soybeans pricing at the market. This study uses a hedonic model to evaluate price differentials associated with soybean quality based on grain elevator data during the 1998 production period. Foreign material, moisture, bean damage, and net weight were found to significantly influence the cash price of soybeans.hedonic, quality, discount, Crop Production/Industries, Demand and Price Analysis,
Infrared remote sensing of cometary parent volatiles from the ground, air, and space
A balanced view of the present generation of infrared instruments for cometary compositional studies is presented. Ground-based instruments are compared with airborne and spaceborne capabilities. An attempt to give examples of the unique science achievable with each is made, and particular emphasis is on the unique aspects of a dedicated Cometary Composition Telescope in earth orbit for investigating the chemical and structural heterogeneity of the cometary nucleus
CONSUMERS' WILLINGNESS TO PAY FOR FOOD SAFETY: A PATHOGEN SPECIFIC ANALYSIS
Estimates of the economic benefits of intervention strategies to make food safer from specific pathogens for different durations of protection are not available. We estimated consumers' willingness to pay for a hypothetical vaccine that would deliver a 1-year, 5- years, 10-years, or lifetime protection against Salmonella, E. coli, or Listeria. We used logit and Tobit models to estimate the economic benefits of food safety measures against these major foodborne pathogens. Based on FoodNet 2002 population survey data, consumers were willing to pay for protection against foodborne pathogens. They were willing to pay more for longer protection and for protection against E. coli compared to Salmonella or Listeria. However, they were less willing to pay if the protection was costly.Contingent valuation, Food Safety, Economic benefits, population survey, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,
Velocity-resolved observations of water in Comet Halley
High resolution (lambda/delta lambda approx. = 3 x 10 to the 5th power) near-infrared observations of H2O emission from Comet Halley were acquired at the time of maximum post-perihelion geocentric Doppler shift. The observed widths and absolute positions of the H2O line profiles reveal characteristics of the molecular velocity field in the coma. These results support H2O outflow from a Sun-lit hemisphere or the entire nucleus, but not from a single, narrow jet emanating from the nucleus. The measured pre- and post-perihelion outflow velocities were 0.9 + or - 0.2 and 1.4 + or - 0.2 km/s, respectively. Temporal variations in the kinematic properties of the outflow were inferred from changes in the spectral line shapes. These results are consistent with the release of H2O into the coma from multiple jets
IMPACT OF STRATEGIC CHANGES ON THE PERFORMANCE OF TRUCKING FIRMS IN THE AGRICULTURAL COMMODITY TRANSPORTATION MARKET
Econometric models were developed to estimate factors that influence strategic changes and evaluate the impacts that strategic changes will have on the subsequent performance of agricultural commodity trucking firms. Results reveal that GDP and change in firm size will have positive impacts on strategic changes made by firms.Public Economics,
Cognitive processing of spatial relations in Euclidean diagrams
The cognitive processing of spatial relations in Euclidean diagrams is central to the diagram-based geometric practice of Euclid's Elements. In this study, we investigate this processing through two dichotomies among spatial relations—metric vs topological and exact vs co-exact—introduced by Manders in his seminal epistemological analysis of Euclid's geometric practice. To this end, we carried out a two-part experiment where participants were asked to judge spatial relations in Euclidean diagrams in a visual half field task design. In the first part, we tested whether the processing of metric vs topological relations yielded the same hemispheric specialization as the processing of coordinate vs categorical relations. In the second part, we investigated the specific performance patterns for the processing of five pairs of exact/co-exact relations, where stimuli for the co-exact relations were divided into three categories depending on their distance from the exact case. Regarding the processing of metric vs topological relations, hemispheric differences were found for only a few of the stimuli used, which may indicate that other processing mechanisms might be at play. Regarding the processing of exact vs co-exact relations, results show that the level of agreement among participants in judging co-exact relations decreases with the distance from the exact case, and this for the five pairs of exact/co-exact relations tested. The philosophical implications of these empirical findings for the epistemological analysis of Euclid's diagram-based geometric practice are spelled out and discussed
The Volatile Composition of the Split Ecliptic comet 73P/Schwassmann-Wachmann 3: A Comparison of Fragments C and B
The composition of fragments C and B of the Jupiter-family comet 73P/Schwassmann-Wachmann 3 (SW3) was investigated in early April of 2006 at IR wavelengths using high-dispersion echelle spectroscopy. Both fragments were depleted in ethane, and C was depleted in most forms of volatile carbon. In particular, fragment C shows a severe depletion of CH_(3)OH but a "normal" abundance of HCN (which has a similar volatility). Thermal processing is a possible explanation, but since fragment B is perhaps sublimating fresher material because of the frequent outbursts and fragmentation, the observed depletions might have cosmogonic implications. The chemistry of the volatile ices in SW3, like in the Oort Cloud comet C/1999 S4 (LINEAR), may be associated with sublimation of icy mantles from precometary grains followed by subsequent gas-phase chemistry and recondensation
AN ANALYSIS OF INTERMODAL INFORMATION TECHNOLOGY USAGE BY INTERMODAL PORTS AND TERMINALS IN THE AGRICULTURAL AND FOOD- PRODUCT MARKET
Agribusiness, Research and Development/Tech Change/Emerging Technologies,
Non-detection of L-band Line Emission from the Exoplanet HD189733b
We attempt to confirm bright non-local thermodynamic equilibrium (non-LTE) emission from the exoplanet HD 189733b at 3.25 μm, as recently reported by Swain et al. based on observations at low spectral resolving power (λ/δλ ≈ 30). Non-LTE emission lines from gas in an exoplanet atmosphere will not be significantly broadened by collisions, so the measured emission intensity per resolution element must be substantially brighter when observed at high spectral resolving power. We observed the planet before, during, and after a secondary eclipse event at a resolving power λ/δλ = 27, 000 using the NIRSPEC spectrometer on the Keck II telescope. Our spectra cover a spectral window near the peak found by Swain et al., and we compare emission cases that could account for the magnitude and wavelength dependence of the Swain et al. result with our final spectral residuals. To model the expected line emission, we use a general non-equilibrium formulation to synthesize emission features from all plausible molecules that emit in this spectral region. In every case, we detect no line emission to a high degree of confidence. After considering possible explanations for the Swain et al. results and the disparity with our own data, we conclude that an astrophysical source for the putative non-LTE emission is unlikely. We note that the wavelength dependence of the signal seen by Swain et al. closely matches the 2ν_2 band of water vapor at 300 K, and we suggest that an imperfect correction for telluric water is the source of the feature claimed by Swain et al
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