5,758 research outputs found

    Extent and Characteristics of Retail Fresh Beef Branding

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    Limited information exists regarding the extent and characteristics of branded fresh beef. Retail package data from a sample of grocery stores in three metropolitan areas enabled determining the extent of branded beef for ground beef, roasts, and steaks. Logit models identified factors affecting the probability of beef products being branded, and the probability of beef products carrying specific types of brands compared with store brands and generic (unbranded) beef. The extent of branded beef and type of brand both varied by store type, specific product, quality designation, package type, and presence of special labeling.Marketing,

    Fundamental study of transpiration cooling

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    Isothermal and non-isothermal pressure drop data and heat transfer data generated on porous 304L stainless steel wire forms, sintered spherical stainless steel powder, and sintered spherical OFHC copper powder are reported and correlated. Pressure drop data was collected over a temperature range from 500 R to 2000 R and heat transfer data collected over a heat flux range from 5 to 15 BTU/in2/sec. It was found that flow data could be correlated independently of transpirant temperature and type (i.e., H2, N2). It was also found that no simple relation between heat transfer coefficient and specimen porosity was obtainable

    STM Studies of Synthetic Peptide Monolayers

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    We have used scanning probe microscopy to investigate self-assembled monolayers of chemically synthesized peptides. We find that the peptides form a dense uniform monolayer, above which is found a sparse additional layer. Using scanning tunneling microscopy, submolecular resolution can be obtained, revealing the alpha helices which constitute the peptide. The nature of the images is not significantly affected by the incorporation of redox cofactors (hemes) in the peptides.Comment: 4 pages, 3 figures (4 gifs); to appear in the Proceedings of the XIIth Int. Winterschool on Electronic Properties of Novel Materials "Molecular Nanostructures", Kirchberg/Tyrol, Febr. 199

    Clues to the nature of dark matter from first galaxies

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    We use thirty-eight high-resolution simulations of galaxy formation between redshift 10 and 5 to study the impact of a 3 keV warm dark matter (WDM) candidate on the high-redshift Universe. We focus our attention on the stellar mass function and the global star formation rate and consider the consequences for reionization, namely the neutral hydrogen fraction evolution and the electron scattering optical depth. We find that three different effects contribute to differentiate warm and cold dark matter (CDM) predictions: WDM suppresses the number of haloes with mass less than few 10910^9 M_{\odot}; at a fixed halo mass, WDM produces fewer stars than CDM; and finally at halo masses below 10910^9 M_{\odot}, WDM has a larger fraction of dark haloes than CDM post-reionization. These three effects combine to produce a lower stellar mass function in WDM for galaxies with stellar masses at and below 107\sim 10^7 M_{\odot}. For z>7z > 7, the global star formation density is lower by a factor of two in the WDM scenario, and for a fixed escape fraction, the fraction of neutral hydrogen is higher by 0.3 at z6z \sim 6. This latter quantity can be partially reconciled with CDM and observations only by increasing the escape fraction from 23 per cent to 34 per cent. Overall, our study shows that galaxy formation simulations at high redshift are a key tool to differentiate between dark matter candidates given a model for baryonic physics.Comment: 11 pages, 8 figures, submitted to MNRA

    Nurse telephone triage for same day appointments in general practice: multiple interrupted time series trial of effect on workload and costs

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    OBJECTIVE: To compare the workloads of general practitioners and nurses and costs of patient care for nurse telephone triage and standard management of requests for same day appointments in routine primary care. DESIGN: Multiple interrupted time series using sequential introduction of experimental triage system in different sites with repeated measures taken one week in every month for 12 months. SETTING: Three primary care sites in York. Participants: 4685 patients: 1233 in standard management, 3452 in the triage system. All patients requesting same day appointments during study weeks were included in the trial. MAIN OUTCOME MEASURES: Type of consultation (telephone, appointment, or visit), time taken for consultation, presenting complaints, use of services during the month after same day contact, and costs of drugs and same day, follow up, and emergency care. RESULTS: The triage system reduced appointments with general practitioner by 29-44%. Compared with standard management, the triage system had a relative risk (95% confidence interval) of 0.85 (0.72 to 1.00) for home visits, 2.41 (2.08 to 2.80) for telephone care, and 3.79 (3.21 to 4.48) for nurse care. Mean overall time in the triage system was 1.70 minutes longer, but mean general practitioner time was reduced by 2.45 minutes. Routine appointments and nursing time increased, as did out of hours and accident and emergency attendance. Costs did not differ significantly between standard management and triage: mean difference £1.48 more per patient for triage (95% confidence interval -0.19 to 3.15). CONCLUSIONS: Triage reduced the number of same day appointments with general practitioners but resulted in busier routine surgeries, increased nursing time, and a small but significant increase in out of hours and accident and emergency attendance. Consequently, triage does not reduce overall costs per patient for managing same day appointments

    NIHAO XX: The impact of the star formation threshold on the cusp-core transformation of cold dark matter haloes

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    We use cosmological hydrodynamical galaxy formation simulations from the NIHAO project to investigate the impact of the threshold for star formation on the response of the dark matter (DM) halo to baryonic processes. The fiducial NIHAO threshold, n=10cm3n=10\, {\rm cm}^{-3}, results in strong expansion of the DM halo in galaxies with stellar masses in the range 107.5<Mstar<109.5M10^{7.5} < M_{star} < 10^{9.5} M_{\odot}. We find that lower thresholds such as n=0.1n=0.1 (as employed by the EAGLE/APOSTLE and Illustris/AURIGA projects) do not result in significant halo expansion at any mass scale. Halo expansion driven by supernova feedback requires significant fluctuations in the local gas fraction on sub-dynamical times (i.e., < 50 Myr at galaxy half-light radii), which are themselves caused by variability in the star formation rate. At one per cent of the virial radius, simulations with n=10n=10 have gas fractions of 0.2\simeq 0.2 and variations of 0.1\simeq 0.1, while n=0.1n=0.1 simulations have order of magnitude lower gas fractions and hence do not expand the halo. The observed DM circular velocities of nearby dwarf galaxies are inconsistent with CDM simulations with n=0.1n=0.1 and n=1n=1, but in reasonable agreement with n=10n=10. Star formation rates are more variable for higher nn, lower galaxy masses, and when star formation is measured on shorter time scales. For example, simulations with n=10n=10 have up to 0.4 dex higher scatter in specific star formation rates than simulations with n=0.1n=0.1. Thus observationally constraining the sub-grid model for star formation, and hence the nature of DM, should be possible in the near future.Comment: 18 pages, 13 figures, accepted to MNRA

    The edge of galaxy formation III: The effects of warm dark matter on Milky Way satellites and field dwarfs

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    In this third paper of the series, we investigate the effects of warm dark matter with a particle mass of mWDM=3keVm_\mathrm{WDM}=3\,\mathrm{keV} on the smallest galaxies in our Universe. We present a sample of 21 hydrodynamical cosmological simulations of dwarf galaxies and 20 simulations of satellite-host galaxy interaction that we performed both in a Cold Dark Matter (CDM) and Warm Dark Matter (WDM) scenario. In the WDM simulations, we observe a higher critical mass for the onset of star formation. Structure growth is delayed in WDM, as a result WDM haloes have a stellar population on average two Gyrs younger than their CDM counterparts. Nevertheless, despite this delayed star formation, CDM and WDM galaxies are both able to reproduce the observed scaling relations for velocity dispersion, stellar mass, size, and metallicity at z=0z=0. WDM satellite haloes in a Milky Way mass host are more susceptible to tidal stripping due to their lower concentrations, but their galaxies can even survive longer than the CDM counterparts if they live in a dark matter halo with a steeper central slope. In agreement with our previous CDM satellite study we observe a steepening of the WDM satellites' central dark matter density slope due to stripping. The difference in the average stellar age for satellite galaxies, between CDM and WDM, could be used in the future for disentangling these two models.Comment: 10 pages, 11 figures, accepted for publication on MNRA

    Magnetically-controlled velocity selection in a cold atom sample using stimulated Raman transitions

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    We observe velocity-selective two-photon resonances in a cold atom cloud in the presence of a magnetic field. We use these resonances to demonstrate a simple magnetometer with sub-mG resolution. The technique is particularly useful for zeroing the magnetic field and does not require any additional laser frequencies than are already used for standard magneto-optical traps. We verify the effects using Faraday rotation spectroscopy.Comment: 5 pages, 6 figure
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