161,348 research outputs found
Lunar magnetization concentrations (MAGCONS) antipodal to young large impact basins
Electron reflection measurements from Apollo 15 and 16 subsatellites show that patches of strong surface magnetic fields ranging in size from less than about 7 km to greater than 500 km are distributed over the surface of the Moon. With the exception of a few regions, no obvious association to surface geology has been found. Researchers examined the antipodes of 23 winged impact basins for which electron reflection measurements are available. It was concluded that the apparent temporal variations for the basin antipodes may reflect real variations in the lunar magnetic field
Frequency Locking in Spatially Extended Systems
A variant of the complex Ginzburg-Landau equation is used to investigate the
frequency locking phenomena in spatially extended systems. With appropriate
parameter values, a variety of frequency-locked patterns including flats,
fronts, labyrinths and fronts emerge. We show that in spatially
extended systems, frequency locking can be enhanced or suppressed by diffusive
coupling. Novel patterns such as chaotically bursting domains and target
patterns are also observed during the transition to locking
Organic Premiums of U.S. Fresh Produce
The study uses the 2005 Nielsen Homescan panel data to estimate price premiums and discounts associated with product attributes, market factors, and consumer characteristics, focusing on the organic attribute for 5 major fresh fruits and 5 major fresh vegetables in the United States. The results suggest that the organic attribute commands a significant price premium, which varies greatly from 13 cents per pound for bananas to 86 cents per pound for strawberries among fresh fruits and from 13 cents per pound for onions to 50 cents per pound for peppers among fresh vegetables. In terms of percentages, the estimated organic price premiums vary from 20% above prices paid for conventional grapes to 42% for strawberries among fresh fruits and from 15% above prices paid for conventional carrots and tomatoes to 60% for potatoes. Furthermore, prices paid for fresh produce are found to vary by other product attributes, market factors, and household characteristics.fresh fruits and vegetables, hedonic price, organic produce, organic premium, product attributes, Nielsen Homescan, Agricultural Finance,
Origin of electron-hole asymmetry in the scanning tunneling spectrum of
We have developed a material specific theoretical framework for modelling
scanning tunneling spectroscopy (STS) of high temperature superconducting
materials in the normal as well as the superconducting state. Results for
(Bi2212) show clearly that the tunneling process
strongly modifies the STS spectrum from the local density of states (LDOS) of
the orbital of Cu. The dominant tunneling channel to the surface
Bi involves the orbitals of the four neighbouring Cu atoms. In
accord with experimental observations, the computed spectrum displays a
remarkable asymmetry between the processes of electron injection and
extraction, which arises from contributions of Cu and other orbitals
to the tunneling current.Comment: 5 pages, 4 figures, published in PR
How Much are Consumers Paying for Organic Baby Food?
Using retail purchase data, price premiums and discounts associated with household demographics, market factors, and product attributes (focusing on the organic attribute for strained baby food) are estimated using a hedonic pricing model. Results suggest that the organic premium ranges from about 12 to 49 percent in 2004 and from 30 to 52 percent in 2006. Tests for significant changes relative to product attributes show that while the price of conventional baby food has stayed relatively the same, the premium for organic baby food has increased.organic baby food, hedonic price, market factors, product attributes, Nielsen Homescan, organic premium, Consumer/Household Economics, Demand and Price Analysis,
Investigation of superlattice device structures
This report describes the investigation of growth properties, and the structure of epitaxial multilayer Si(Si(1x)Ge(x)) films grown on bulk Silicon Substrates. It also describes the fabrication and characterization of MOSFET and MESFET devices made on these epitaxial films. Films were grown in a CVD reactor using hydrides of Si and Ge with H2 and He as carrier gases. Growth temperatures were between 900 C and 1050 C with most films grown at 1000 C. Layer thickness was between 300A and 2000A and total film thickness was between 0.25 micro m and 7 micro m. The Ge content (X) in the alloy layers was between .05 and 0.2. N-type multilayer films grown on (100) p-type Si showed Hall mobility in the range 1000 to 1500 sq cm/v for an average carrier concentration of approx. 10 to the 16th power/cu cm. This is up to 50% higher than the Hall mobility observed in epitaxial Si films grown under the same conditions and with the same average carrier concentration. The mobility enhancement occurred in films with average carrier concentration (n) from 0.7 x 10 to the 16th power to 2 x 10 to the 17th power/cu cm, and total film thickness greater than 1.0 micro m. No mobility enhancement was seen in n-type multilayer films grown on (111) Si or in p-type multilayer films. The structure of the films was investigated was using SEM, TEM, AES, SIMS, and X-ray double crystal diffraction techniques. The film composition profile (AES, SIMS) showed that the transition region between layers is of the order of about 100A. The TEM examination revealed a well defined layered structure with fairly sharp interfaces and good crystalline quality. It also showed that the first few layers of the film (closest to the substrate) are uneven, most probably due to the initial growth pattern of the epitaxial film where growth occurs first in isolated islands that eventually growth and coalesce. The X-ray diffraction measurement determined the elastic strain and strain relief in the alloy layers of the film and the elastic strain in the intervening Si layers
Does Price or Income Affect Organic Choice? Analysis of U.S. Fresh Produce Users
This study analyzes consumer purchasing behavior of organic fresh fruits and vegetables using the 2006 Nielsen Homescan panel. An ordered logit model was estimated to quantify the impacts of economic and socio-demographic factors on the probability of a household belonging to a specific organic user group—devoted, casual, or nonuser. Results suggest that price and income, to some extent, affect consumer purchases of organic produce. Additionally, the profile of an organic produce user is most likely to consist of an Hispanic household residing in the Western United States with children under 6 years old and a household head older than 54 years with at least a college degree.Nielsen Homescan data, ordered logit, organic fruits and vegetables, user groups, Agribusiness, Consumer/Household Economics, Crop Production/Industries, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, C25, D12, M31, Q11,
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