2,060 research outputs found

    REGULATORY TARGETS AND REGIMES FOR FOOD SAFETY: A COMPARISON OF NORTH AMERICAN AND EUROPEAN APPROACHES

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    Food quality, international trade, harmonization, mutual recognition, Food Consumption/Nutrition/Food Safety,

    Discovery of 6.035GHz Hydroxyl Maser Flares in IRAS18566+0408

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    We report the discovery of 6.035GHz hydroxyl (OH) maser flares toward the massive star forming region IRAS18566+0408 (G37.55+0.20), which is the only region known to show periodic formaldehyde (4.8 GHz H2CO) and methanol (6.7 GHz CH3OH) maser flares. The observations were conducted between October 2008 and January 2010 with the 305m Arecibo Telescope in Puerto Rico. We detected two flare events, one in March 2009, and one in September to November 2009. The OH maser flares are not simultaneous with the H2CO flares, but may be correlated with CH3OH flares from a component at corresponding velocities. A possible correlated variability of OH and CH3OH masers in IRAS18566+0408 is consistent with a common excitation mechanism (IR pumping) as predicted by theory.Comment: Accepted for publication in the Astrophysical Journa

    FOOD SAFETY INNOVATION IN THE UNITED STATES: EVIDENCE FROM THE MEAT INDUSTRY

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    Recent industry innovations improving the safety of the Nation's meat supply range from new pathogen tests, high-tech equipment, and supply chain management systems, to new surveillance networks. Despite these and other improvements, the market incentives that motivate private firms to invest in innovation seem to be fairly weak. Results from an ERS survey of U.S. meat and poultry slaughter and processing plants and two case studies of innovation in the U.S. beef industry reveal that the industry has developed a number of mechanisms to overcome that weakness and to stimulate investment in food safety innovation. Industry experience suggests that government policy can increase food safety innovation by reducing informational asymmetries and strengthening the ability of innovating firms to appropriate the benefits of their investments.Food safety, innovation, meat, asymmetric information, Beef Steam Pasteurization System, Bacterial Pathogen Sampling and Testing Program, Food Consumption/Nutrition/Food Safety, Livestock Production/Industries,

    Contributions of high- and low-quality patches to a metapopulation with stochastic disturbance

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    © The Author(s), 2010. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Theoretical Ecology 5 (2012): 167-179, doi:10.1007/s12080-010-0106-9.Studies of time-invariant matrix metapopulation models indicate that metapopulation growth rate is usually more sensitive to the vital rates of individuals in high-quality (i.e., good) patches than in low-quality (i.e., bad) patches. This suggests that, given a choice, management efforts should focus on good rather than bad patches. Here, we examine the sensitivity of metapopulation growth rate for a two-patch matrix metapopulation model with and without stochastic disturbance and found cases where managers can more efficiently increase metapopulation growth rate by focusing efforts on the bad patch. In our model, net reproductive rate differs between the two patches so that in the absence of dispersal, one patch is high quality and the other low quality. Disturbance, when present, reduces net reproductive rate with equal frequency and intensity in both patches. The stochastic disturbance model gives qualitatively similar results to the deterministic model. In most cases, metapopulation growth rate was elastic to changes in net reproductive rate of individuals in the good patch than the bad patch. However, when the majority of individuals are located in the bad patch, metapopulation growth rate can be most elastic to net reproductive rate in the bad patch. We expand the model to include two stages and parameterize the patches using data for the softshell clam, Mya arenaria. With a two-stage demographic model, the elasticities of metapopulation growth rate to parameters in the bad patch increase, while elasticities to the same parameters in the good patch decrease. Metapopulation growth rate is most elastic to adult survival in the population of the good patch for all scenarios we examine. If the majority of the metapopulation is located in the bad patch, the elasticity to parameters of that population increase but do not surpass elasticity to parameters in the good patch. This model can be expanded to include additional patches, multiple stages, stochastic dispersal, and complex demography.Financial support was provided by the Woods Hole Oceanographic Institution Academic Programs Office; National Science Foundation grants OCE-0326734, OCE- 0215905, OCE-0349177, DEB-0235692, DEB-0816514, DMS- 0532378, OCE-1031256, and ATM-0428122; and by National Oceanic and Atmospheric Administration National Sea Grant College Program Office, Department of Commerce, under Grant No. NA86RG0075 (Woods Hole Oceanographic Institution Sea Grant Project No. R/0-32), and Grant No. NA16RG2273 (Woods Hole Oceanographic Institution Sea Grant Project No. R/0-35)

    Concepts of microdosimetry

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    This is the first part of an investigation of microdosimetric concepts relevant to numerical calculations. The definitions of the microdosimetric quantities are reviewed and formalized, and some additional conventions are adopted. The common interpretation of the quantities in terms of energy imparted to spherical sites is contrasted with their interpretation as the result of a diffusion process applied to the initial spatial pattern of energy transfers in the irradiated medium

    Maser Source Finding Methods in HOPS

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    The {\bf H}2_2{\bf O} Southern Galactic {\bf P}lane {\bf S}urvey (HOPS) has observed 100 square degrees of the Galactic plane, using the Mopra radio telescope to search for emission from multiple spectral lines in the 12\,mm band (19.5\,--\,27.5\,GHz). Perhaps the most important of these spectral lines is the 22.2\,GHz water maser transition. We describe the methods used to identify water maser candidates and subsequent confirmation of the sources. Our methods involve a simple determination of likely candidates by searching peak emission maps, utilising the intrinsic nature of water maser emission - spatially unresolved and spectrally narrow-lined. We estimate completeness limits and compare our method with results from the {\sc Duchamp} source finder. We find that the two methods perform similarly. We conclude that the similarity in performance is due to the intrinsic limitation of the noise characteristics of the data. The advantages of our method are that it is slightly more efficient in eliminating spurious detections and is simple to implement. The disadvantage is that it is a manual method of finding sources and so is not practical on datasets much larger than HOPS, or for datasets with extended emission that needs to be characterised. We outline a two-stage method for the most efficient means of finding masers, using {\sc Duchamp}.Comment: 8 pages, 1 table, 4 figures. Accepted for publication in PASA special issue on Source Finding & Visualisatio

    The Distances of SNR W41 and overlapping HII regions

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    New HI images from the VLA Galactic Plane Survey show prominent absorption features associated with the supernovae remnant G23.3-0.3 (SNR W41). We highlight the HI absorption spectra and the 13^{13}CO emission spectra of eight small regions on the face of W41, including four HII regions, three non-thermal emission regions and one unclassified region. The maximum velocity of absorption for W41 is 78±\pm2 km/s and the CO cloud at radial velocity 95±\pm5 km/s is behind W41. Because an extended TeV source, a diffuse X-ray enhancement and a large molecular cloud at radial velocity 77±\pm5 km/s are also projected at the center of W41, these yield the kinematic distance of 3.9 to 4.5 kpc for W41. For HII regions, our analyses reveal that both G23.42-0.21 and G23.07+0.25 are at the far kinematic distances (\sim9.9 kpc and \sim 10.6 kpc respectively) of their recombination-line velocities (103±\pm0.5 km/s and 89.6±\pm2.1 km/s respectively), G23.07-0.37 is at the near kinematic distance (4.4±\pm0.3 kpc) of its recombination-line velocity (82.7±\pm2.0 km/s), and G23.27-0.27 is probably at the near kinematic distance (4.1±\pm0.3 kpc) of its recombination-line velocity (76.1±\pm0.6 km/s).Comment: 11 pages, 3 figs., 2 tables, accepted by A

    Five-Loop Vacuum Energy Beta Function in phi^4 Theory with O(N)-Symmetric and Cubic Interactions

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    The beta function of the vacuum energy density is analytically computed at the five-loop level in O(N)-symmetric phi^4 theory, using dimensional regularization in conjunction with the MSbar scheme. The result for the case of a cubic anisotropy is also given. It is pointed out how to also obtain the beta function of the coupling and the gamma function of the mass from vacuum graphs. This method may be easier than traditional approaches.Comment: 16 pages, LaTeX; "note added" fixe
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