1,487 research outputs found

    Vascular perfusion chilling of red meat carcasses - A feasibility study.

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    Meat carcasses must be chilled to below 7°C before leaving the slaughterhouse. Typically this is done by passing cold air over the surfaces of eviscerated and de-hided carcasses. This surface cooling can take many hours to reduce centre temperatures to below 7°C. In vascular perfusion chilling (VPC), a cold fluid is circulated through the intact vascular system, offering significant reductions in cooling time. This paper describes a small feasibility study to evaluate vascular perfusion techniques for rapid chilling of lamb carcasses using a proprietary Flo-ice(™) system. This produces pumpable ice slurries containing very fine ice particles, suitable for circulating through vascular systems. VPC was found to be capable of rapid initial reduction of carcass temperatures in comparison with air chilling (mean times to 20°C in deep legs were reduced from 2.6 to 1.3h, which was significantly different at P<0.05). In all cases however, uptake of perfusate into the carcasses occurred. This limited the duration of the perfusion treatment and as a result restricted the period of enhanced cooling. Samples from carcasses treated with VPC were lighter (P<0.05, with mean measured L value increasing from 43.4 to 46.8) and more yellow (P<0.05, with mean measured b value increasing from 6.7 to 7.9) than samples from conventionally chilled carcasses, and had lower shear force values when cooked (P<0.05, with mean force reducing from 10.0 to 6.8kg). This was most probably due to the added water in the meat. Microbial quality of the meat was not significantly affected by the perfusion treatments

    Stability, fatty acid composition and sensory properties of the <i>M. Longissimus </i>muscle from beef steers grazing either chicory / ryegrass or ryegrass

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    Research has shown both production and health benefits for the use of chicory (Cichorium intybus) within ruminant diets. Despite this, little was known about the the effects of this forage, containing differing fatty acid profiles and secondary plant compounds compared to ryegrass, on beef stability, fatty acid composition or sensory properties. An experiment was conducted to investigate whether the inclusion of chicory in the diet of grazing beef steers would alter the meat stability, fatty acid composition and sensory properties of the M. Longissimus muscle compared to beef steers grazing perennial ryegrass (Lolium perenne). Triplicate 2 ha plots were established with a chicory (cv. Puna II) / perennial ryegrass (cv. Premium) mix or a perennial ryegrass (cv. Premium) control. A core group of 36 Belgian Blue - cross steers were used within a two-year beef finishing experiment (n=6 per replicate plot). In the second grazing year, steers were slaughtered as they reached a target fat class of 3. After dressing, half carcass sides were hung for 48 h and then then quartered between the junction of the 10th and 11th rib. Muscle pH was checked at 2 and 48 h post-slaughter. A 250 mm-long section of the hindloin joint containing the M. Longissimus lumborum muscle was removed from the left side of the carcass, posterior to the 10th rib. A 20 mm-thick steak was cut and a muscle sample was vacuum packed and frozen at -20? C for subsequent analysis of vitamin E, a further steak being retained for fatty acid analysis. The remaining section of the loin was vacuum-packed in modified atmosphere packs and subjected to simulated retail display. The remaining section of the conditioned loin was used for sensory analysis. Data on pH, vitamin E concentration and colour stability in a simulated retail display showed there were no effects of including chicory in the diet of grazing beef steers on meat stability. There were also no differences found in the fatty acid composition or the overall eating quality of the steaks from the two treatments. In conclusion, there were no substantive effects of including chicory in the swards of grazing beef cattle on meat stability, fatty acid composition or sensory properties when compared with beef steers grazing ryegrass-only swards.publishersversionPeer reviewe

    Spectral Analysis of the September 2017 Solar Energetic Particle Events

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    An interval of exceptional solar activity was registered in early September 2017, late in the decay phase of solar cycle 24, involving the complex Active Region 12673 as it rotated across the western hemisphere with respect to Earth. A large number of eruptions occurred between 4 and 10 September, including four associated with Xclass flares. The X9.3 flare on 6 September and the X8.2 flare on 10 September are currently the two largest during cycle 24. Both were accompanied by fast coronal mass ejections and gave rise to solar energetic particle (SEP) events measured by nearEarth spacecraft. In particular, the partially occulted solar event on 10 September triggered a groundlevel enhancement (GLE), the second GLE of cycle 24. A further, much less energetic SEP event was recorded on 4 September. In this work we analyze observations by the Advanced Composition Explorer (ACE) and the Geostationary Operational Environmental Satellites (GOES), estimating the SEP eventintegrated spectra above 300 keV and carrying out a detailed study of the spectral shape temporal evolution. Derived spectra are characterized by a lowenergy break at few/tens of MeV; the 10 September event spectrum, extending up to 1 GeV, exhibits an additional rollover at several hundred MeV. We discuss the spectral interpretation in the scenario of shock acceleration and in terms of other important external influences related to interplanetary transport and magnetic connectivity, taking advantage of multipoint observations from the Solar Terrestrial Relations Observatory. Spectral results are also compared with those obtained for the 17 May 2012 GLE event

    Analysis of ontogenetic growth trends in two marine Antarctic bivalves Yoldia eightsi and Laternula elliptica: Implications for sclerochronology

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    There is an increasing use of marine species as paleoclimate recorders for the marine realm. These archives provide novel baseline records of past oceanographic variability in regions devoid of instrumental observations. Here we report results of a study of the ontogenetic growth pattern of two Antarctic marine bivalve molluscs: Yoldia eightsi and Laternula elliptica from West Antarctic Peninsula populations using negative exponential detrending technique and multi-taper method spectral analysis. Our data show the growth of both Y. eightsi and L. elliptica follow a general negative exponential trend over their longevity. However, our analyses also identified an innate 9.06 year periodic endogenous growth rhythm in the growth increment pattern of Y. eightsi and two innate periodic growth rhythms, 5 and 6.6 year period, were found in L. elliptica. We hypothesize that the Y. eightsi endogenous growth rhythm may be related to the reallocation of energetic resources between somatic growth and gametogenesis although more biological data are required to test this hypothesis. Further work into L. elliptica biology is required to understand the possible meaning of the innate growth rhythms found for this species. The identification growth rhythms is important not only for their biological significance but also in sclerochronological analysis because of their importance in developing paleoenvironmental reconstructions

    “Cross” Supermicelles via the Hierarchical Assembly of Amphiphilic Cylindrical Triblock Comicelles

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    Self-assembled “cross” architectures are well-known in biological systems (as illustrated by chromosomes, for example); however, comparable synthetic structures are extremely rare. Herein we report an in depth study of the hierarchical assembly of the amphiphilic cylindrical P–H–P triblock comicelles with polar (P) coronal ends and a hydrophobic (H) central periphery in a selective solvent for the terminal segments which allows access to “cross” supermicelles under certain conditions. Well-defined P–H–P triblock comicelles M­(PFS-<i>b</i>-PtBA)-<i>b</i>-M­(PFS-<i>b</i>-PDMS)-<i>b</i>-M­(PFS-<i>b</i>-PtBA) (M = micelle segment, PFS = polyferrocenyldimethylsilane, PtBA = poly­(<i>tert</i>-butyl acrylate), and PDMS = polydimethylsiloxane) were created by the living crystallization-driven self-assembly (CDSA) method. By manipulating two factors in the supermicelles, namely the H segment-solvent interfacial energy (through the central H segment length, <i>L</i><sub>1</sub>) and coronal steric effects (via the PtBA corona chain length in the P segment, <i>L</i><sub>2</sub> related to the degree of polymerization DP<sub>2</sub>) the aggregation of the triblock comicelles could be finely tuned. This allowed a phase-diagram to be constructed that can be extended to other triblock comicelles with different coronas on the central or end segment where “cross” supermicelles were exclusively formed under predicted conditions. Laser scanning confocal microscopy (LSCM) analysis of dye-labeled “cross” supermicelles, and block “cross” supermicelles formed by addition of a different unimer to the arm termini, provided complementary characterization to transmission electron microscopy (TEM) and dynamic light scattering (DLS) and confirmed the existence of these “cross” supermicelles as kinetically stable, micron-size colloidally stable structures in solution
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