35,701 research outputs found

    INCREASING FOOD RECOVERY FROM FARMERS' MARKETS: A PRELIMINARY ANALYSIS

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    Collecting unsold food discarded at farmer's markets has the potential to allow nonprofit food recovery and gleaning organizations to distribute significant quantities of wholesome, unsold fruits and vegetables to needy families. Donations of this unsold produce by the participants at these markets can generate tangible benefits: increased private food assistance and better nutrition for lower income families. The Geographical Information System (GIS) analysis presented in this study indicates that there is potential to strengthen the links between farmer's markets and nonprofit food recovery and gleaning organizations in many areas of the United States.Food Consumption/Nutrition/Food Safety, Marketing,

    Why Are Prices Sticky? The Dynamics of Wholesale Gasoline Prices

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    The menu-cost interpretation of sticky prices implies that the probability of a price change should depend on the past history of prices and fundamentals only through the gap between the current price and the frictionless price. We find that this prediction is broadly consistent with the behavior of 9 Philadelphia gasoline wholesalers. We nevertheless reject the menu-cost model as a literal description of these firms' behavior, arguing instead that price stickiness arises from strategic considerations of how customers and competitors will react to price changes.

    Theoretical Predictions for Surface Brightness Fluctuations and Implications for Stellar Populations of Elliptical Galaxies

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    (Abridged) We present new theoretical predictions for surface brightness fluctuations (SBFs) using models optimized for this purpose. Our predictions agree well with SBF data for globular clusters and elliptical galaxies. We provide refined theoretical calibrations and k-corrections needed to use SBFs as standard candles. We suggest that SBF distance measurements can be improved by using a filter around 1 micron and calibrating I-band SBFs with the integrated V-K galaxy color. We also show that current SBF data provide useful constraints on population synthesis models, and we suggest SBF-based tests for future models. The data favor specific choices of evolutionary tracks and spectra in the models among the several choices allowed by comparisons based on only integrated light. In addition, the tightness of the empirical I-band SBF calibration suggests that model uncertainties in post-main sequence lifetimes are less than +/-50% and that the IMF in ellipticals is not much steeper than that in the solar neighborhood. Finally, we analyze the potential of SBFs for probing unresolved stellar populations. We find that optical/near-IR SBFs are much more sensitive to metallicity than to age. Therefore, SBF magnitudes and colors are a valuable tool to break the age/metallicity degeneracy. Our initial results suggest that the most luminous stellar populations of bright cluster galaxies have roughly solar metallicities and about a factor of three spread in age.Comment: Astrophysical Journal, in press (uses Apr 20, 2000 version of emulateapj5.sty). Reposted version has a minor cosmetic change to Table

    The Local Group: The Ultimate Deep Field

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    Near-field cosmology -- using detailed observations of the Local Group and its environs to study wide-ranging questions in galaxy formation and dark matter physics -- has become a mature and rich field over the past decade. There are lingering concerns, however, that the relatively small size of the present-day Local Group (2\sim 2 Mpc diameter) imposes insurmountable sample-variance uncertainties, limiting its broader utility. We consider the region spanned by the Local Group's progenitors at earlier times and show that it reaches 373' \approx 7 co-moving Mpc in linear size (a volume of 350Mpc3\approx 350\,{\rm Mpc}^3) at z=7z=7. This size at early cosmic epochs is large enough to be representative in terms of the matter density and counts of dark matter halos with Mvir(z=7)2×109MM_{\rm vir}(z=7) \lesssim 2\times 10^{9}\,M_{\odot}. The Local Group's stellar fossil record traces the cosmic evolution of galaxies with 103M(z=0)/M10910^{3} \lesssim M_{\star}(z=0) / M_{\odot} \lesssim 10^{9} (reaching M1500>9M_{1500} > -9 at z7z\sim7) over a region that is comparable to or larger than the Hubble Ultra-Deep Field (HUDF) for the entire history of the Universe. It is highly complementary to the HUDF, as it probes much fainter galaxies but does not contain the intrinsically rarer, brighter sources that are detectable in the HUDF. Archaeological studies in the Local Group also provide the ability to trace the evolution of individual galaxies across time as opposed to evaluating statistical connections between temporally distinct populations. In the JWST era, resolved stellar populations will probe regions larger than the HUDF and any deep JWST fields, further enhancing the value of near-field cosmology.Comment: 6 pages, 5 figures; MNRAS Letters, in pres

    A new genus of Prioninae (Coleoptera, Cerambycidae)

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    Neoma, a new genus of Cerambycidae (Coleoptera: Cerambycidae: Prioninae: Macrotomini) is described for Mallodonopsis corrosus Bates, 1879, compared to related genera (Aplagiognathus Thomson, 1861; Archodontes Lameere, 1903; and Mallodonopsis Thomson, 1861), and its tribal position discussed. A lectotype for Mallodonopsis corrosus is here designated with the species redescribed and figured

    Structural characterisation of pre-processed thermoplastic protein derived from bloodmeal

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    Additives are required to convert bloodmeal powder into an extrudable thermoplastic protein-based bioplastic. These include a protein denaturant, a surfactant, a reducing agent and plasticisers. The objective of this work was to assess the structural changes induced in bloodmeal by these additives prior to extrusion. Structure was investigated using Fourier transform infrared (FT-IR) spectroscopy, wide angle X-ray scattering (WAXS) and synchrotron light based FT-IR microspectroscopy. FT-IR results suggested the additives reduced α-helical content. The shape of the amide I region (1600 – 1700 cm⁻¹, representing carbonyl group stretching in the protein backbone) is known to depend on protein secondary structures. Bloodmeal showed a broad, convoluted peak in this region, with a maximum in the range 1648 – 1658 cm⁻¹, associated with α-helices. With processing additives, a dip was seen in the α-helix region, with twin peaks emerging either side of it. Urea, one of the additives, also absorbs in the amide I region and may also contribute to a change in its shape. Analysis of the amide 3 region supported a reduction in the ratio of α helices to β sheets. Further support of structural changes was shown by WAXS. The additives decreased the sharpness of peaks corresponding to 4.8 Å and 10 Å, thought to represent intra-helix spacing and inter-helix packing respectively. FT-IR microspectroscopy at the Australian Synchrotron enabled spatial variations in secondary structure to be explored using peaks in the amide 3 region. Spatial distribution of secondary structure was detected in bloodmeal and thermoplastically modified bloodmeal prior to extrusion (PPM-TEG). Bloodmeal showed domain separation on the approximate order of 10 μm, whilst PPM-TEG appeared to have larger phases and overall reduced α-helical content, relative to beta sheets

    The 1999 Center for Simulation of Dynamic Response in Materials Annual Technical Report

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    Introduction: This annual report describes research accomplishments for FY 99 of the Center for Simulation of Dynamic Response of Materials. The Center is constructing a virtual shock physics facility in which the full three dimensional response of a variety of target materials can be computed for a wide range of compressive, ten- sional, and shear loadings, including those produced by detonation of energetic materials. The goals are to facilitate computation of a variety of experiments in which strong shock and detonation waves are made to impinge on targets consisting of various combinations of materials, compute the subsequent dy- namic response of the target materials, and validate these computations against experimental data
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