3,071 research outputs found
IMPACT OF SOCIOECONOMIC CHARACTERISTICS ON ATTITUDES TOWARD FOOD IRRADIATION
Irradiation of food products is one of several techniques that reduce the risk of food-borne illness. Despite its advantages, the technique has been used sparingly because consumers are wary about this technology. A logit model is used to evaluate the impacts of demographic factors on attitudes toward purchasing foods that have been irradiated and toward paying more for irradiated foods. An important finding of this study is that consumers who are familiar with irradiation are significantly more likely to buy and pay more for irradiated products than those who have never heard of irradiation. This implies that educational programs aimed at informing consumers about the benefits of irradiation can work.Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,
Spin-flip and spin-conserving optical transitions of the nitrogen-vacancy centre in diamond
We map out the first excited state sublevel structure of single nitrogen-vacancy (NV) colour centres in diamond. The excited state is an orbital doublet where one branch supports an efficient cycling transition, while the other can simultaneously support fully allowed optical Raman spin-flip transitions. This is crucial for the success of many recently proposed quantum information applications of the NV defects. We further find that an external electric field can be used to completely control the optical properties of a single centre. Finally, a group theoretical model is developed that explains the observations and provides good physical understanding of the excited state structure
Mid-infrared Selection of Active Galactic Nuclei with the Wide-Field Infrared Survey Explorer. I. Characterizing WISE-selected Active Galactic Nuclei in COSMOS
The Wide-field Infrared Survey Explorer (WISE) is an extremely capable and efficient black hole finder. We present a simple mid-infrared color criterion, W1 â W2 â„ 0.8 (i.e., [3.4]â[4.6] â„0.8, Vega), which identifies 61.9 ± 5.4 active galactic nucleus (AGN) candidates per deg^2 to a depth of W2 ~ 15.0. This implies a much larger census of luminous AGNs than found by typical wide-area surveys, attributable to the fact that mid-infrared selection identifies both unobscured (type 1) and obscured (type 2) AGNs. Optical and soft X-ray surveys alone are highly biased toward only unobscured AGNs, while this simple WISE selection likely identifies even heavily obscured, Compton-thick AGNs. Using deep, public data in the COSMOS field, we explore the properties of WISE-selected AGN candidates. At the mid-infrared depth considered, 160 ÎŒJy at 4.6 ÎŒm, this simple criterion identifies 78% of Spitzer mid-infrared AGN candidates according to the criteria of Stern et al. and the reliability is 95%. We explore the demographics, multiwavelength properties and redshift distribution of WISE-selected AGN candidates in the COSMOS field
Research Supporting Technology Education- Task Force 2.4 Final Report
(First paragraph) ITEA\u27s Board of Directors convened a task force in 2006 to identify research on technology teaching and learning. The resulting database is designed to help teachers, supervisors, and anyone that needs to show research support for technology education. The research was compiled by the following task force members
Population Impact Analysis:A framework for assessing the population impact of a risk or intervention
The Mesozoic along-strike tectono-metamorphic segmentation of Longmen Shan (eastern Tibetan plateau)
The Longmen Shan belt (eastern border of the Tibetan plateau) constitutes a tectonically active region as demonstrated by the occurrence of the unexpected 2008 Mw 7.9 Wenchuan and 2013 Mw 6.6 Lushan earthquakes in the central and southern parts of the belt respectively. These events revealed the necessity of a better understanding of the longâterm geological evolution of the belt and its effect on the present dynamics and crustal structure. New structural and thermobarometric data offer a comprehensive dataset of the paleoâtemperatures across the belt and PâT estimates for lowâgrade metamorphic domains. In the central Longmen Shan, two metamorphic jumps of 150â200°C, 5â6 kbar and ~50 °C, 3â5 kbar acquired during the Early Mesozoic are observed across the Wenchuan and Beichuan faults respectively, attesting to their thrusting movement and unrevealing a major decollement between the allochtonous SongpanâGarze metasedimentary cover (at T > 500°C) and the autochtonous units and the basement (T < 400°C). In the southern Longmen Shan, the only greenschistâfacies metamorphism is observed both in the basement (360 ± 30°C, 6 ± 2 kbar) and in the metasedimentary cover (350 ± 30°C, 3 ± 1 kbar). Peak conditions were reached at c. 80â60 Ma in the basement and c. 55â33 Ma in the cover, c. 50 Ma after the greenschistâfacies metamorphic overprint observed in the central Longmen Shan (c. 150â120 Ma). This alongâstrike metamorphic segmentation coincides well with the present fault segmentation and reveals that the central and southern Longmen Shan experienced different tectonoâmetamorphic histories since the Mesozoic
A comprehensive study of GRB 070125, a most energetic gamma ray burst
We present a comprehensive multiwavelength analysis of the bright, long
duration gamma-ray burst GRB 070125, comprised of observations in -ray,
X-ray, optical, millimeter and centimeter wavebands. Simultaneous fits to the
optical and X-ray light curves favor a break on day 3.78, which we interpret as
the jet break from a collimated outflow. Independent fits to optical and X-ray
bands give similar results in the optical bands but shift the jet break to
around day 10 in the X-ray light curve. We show that for the physical
parameters derived for GRB 070125, inverse Compton scattering effects are
important throughout the afterglow evolution. While inverse Compton scattering
does not affect radio and optical bands, it may be a promising candidate to
delay the jet break in the X-ray band. Radio light curves show rapid flux
variations, which are interpreted as due to interstellar scintillation, and are
used to derive an upper limit of cm on the radius of the
fireball in the lateral expansion phase of the jet. Radio light curves and
spectra suggest a high synchrotron self absorption frequency indicative of the
afterglow shock wave moving in a dense medium. Our broadband modeling favors a
constant density profile for the circumburst medium over a wind-like profile
(). However, keeping in mind the uncertainty of the parameters, it is
difficult to unambiguously distinguish between the two density profiles. Our
broadband fits suggest that \event is a burst with high radiative efficiency
().Comment: 50 pages, 33 figures, sty file included, Appeared in 20 Aug 2008
edition of Astrophysical Journa
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