216 research outputs found

    In vitro ruminal fermentation and fatty acid production by various oil seeds

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    Rumen simulating techniques (Rusitec) were used to determine the impact of diets containing milled oilseeds on the fermentation parameters and amount of fatty acids (FA) in the effluent. High-forage diets containing no oilseeds (control diet (CD)) or 10% oilseed meal from rapeseed (RS), sunflower seed (SS), or flaxseed (FS) were used on a dry matter (DM) basis. No differences in DM digestibility were observed between the diets. Inclusion of SS and FS significantly reduced the pH values of the ruminal fluid, and a significant decline in the ammonia nitrogen (NH3-N) (mg/d) production in effluent was observed in the vessels with SS. Generally, oilseeds in these diets significantly reduced the amount of total fermentation gases (L/d); however, only a tendency toward methane (CH4, %) decrease was detected. The addition of oilseeds also significantly diminished the amount of total volatile fatty acids (VFA) produced (mmol/d). Significant reductions in the amounts of saturated FA in the vessels with RS and FS were observed compared with the CD and a significantly higher amount of monounsaturated fatty acids (MUFA) was noted in the vessels with RS. An increased amount of polyunsaturated fatty acids (PUFA), compared with the CD, was statistically significant only in the vessels with FS.Keywords: Flaxseed, high-forage diet, methane, rapeseed, sunflower see

    Effects of drying procedures on chemical composition and nutritive value of alfalfa forage

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    The effects of various drying procedures of alfalfa forage were evaluated on chemical composition, in vitro neutral detergent fibre (NDF) and dry matter (DM) digestibility, in situ DM, organic matter and crude protein (CP) degradability. The alfalfa had been harvested in the spring growth (early bud and flowering) and first regrowth (late bud and late flowering) periods. The samples were dried at 30 °C (T30), 40 °C (T40), 50 °C (T50), 60 °C (T60) and 100 °C (T100) in a forced-air oven or frozen for one month and then freeze-dried (TFD) or oven-dried at 50 °C (TFREE). Another drying procedure included pre-treatment by heating in a microwave oven (TMO) or in a forced-air oven at 100 °C for 1 hour (T100+50) and then oven-dried at 50 °C. The freeze-drying method was chosen as a reference method. Freeze-dried samples had the lowest NDF, acid detergent fibre (ADF), acid detergent lignin (ADL), neutral detergent insoluble protein (NDIP) and acid detergent insoluble protein contents (P <0.05). Additionally, freeze-dried products had the highest CP, in vitro true digestibility of DM and CP degradability values (P <0.05). There was no added benefit of the TMO in the chemical composition, in vitro digestibility or in situ degradation compared with T50. This study showed that T50 can yield chemical composition, in vitro and in situ results that are similar to those obtained with the freeze-drying method and that this procedure is useful for forage analyses and evaluation.Keywords: freeze-drying, insoluble nitrogen, in vitro digestibility, oven-drying, ruminant

    Biogeochemistry of upland to wetland soils, sediments, and surface waters across Mid-Atlantic and Great Lakes coastal interfaces

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    Transferable and mechanistic understanding of cross-scale interactions is necessary to predict how coastal systems respond to global change. Cohesive datasets across geographically distributed sites can be used to examine how transferable a mechanistic understanding of coastal ecosystem control points is. To address the above research objectives, data were collected by the EXploration of Coastal Hydrobiogeochemistry Across a Network of Gradients and Experiments (EXCHANGE) Consortium – a regionally distributed network of researchers that collaborated on experimental design, methodology, collection, analysis, and publication. The EXCHANGE Consortium collected samples from 52 coastal terrestrial-aquatic interfaces (TAIs) during Fall of 2021. At each TAI, samples collected include soils from across a transverse elevation gradient (i.e., coastal upland forest, transitional forest, and wetland soils), surface waters, and nearshore sediments across research sites in the Great Lakes and Mid-Atlantic regions (Chesapeake and Delaware Bays) of the continental USA. The first campaign measures surface water quality parameters, bulk geochemical parameters on water, soil, and sediment samples, and physicochemical parameters of sediment and soil

    A robust SNP barcode for typing Mycobacterium tuberculosis complex strains

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    Strain-specific genomic diversity in the Mycobacterium tuberculosis complex (MTBC) is an important factor in pathogenesis that may affect virulence, transmissibility, host response and emergence of drug resistance. Several systems have been proposed to classify MTBC strains into distinct lineages and families. Here, we investigate single-nucleotide polymorphisms (SNPs) as robust (stable) markers of genetic variation for phylogenetic analysis. We identify ~92k SNP across a global collection of 1,601 genomes. The SNP-based phylogeny is consistent with the gold-standard regions of difference (RD) classification system. Of the ~7k strain-specific SNPs identified, 62 markers are proposed to discriminate known circulating strains. This SNP-based barcode is the first to cover all main lineages, and classifies a greater number of sublineages than current alternatives. It may be used to classify clinical isolates to evaluate tools to control the disease, including therapeutics and vaccines whose effectiveness may vary by strain type

    Review of the development of cesium iodide photocathodes for application to large RICH detectors

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    CsI photocathodes were studied in order to evaluate their potential use as large photo converters in RICH detectors for the PID system of ALICE at LHC in heavy-ion collider mode. It has been demonstrated that a quantum efficiency close to the reference value obtained on small samples can be obtained on CsI layers evaporated on large pad electrodes operated in a MWPC at atmospheric pressure. We present a survey of the results obtained in the laboratory on small samples irradiated with UV-monochromatic beams and with large area RICH detectors of proximity-focusing geometry in a 3 GeV/c pion beam

    Z_2-Regge versus Standard Regge Calculus in two dimensions

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    We consider two versions of quantum Regge calculus. The Standard Regge Calculus where the quadratic link lengths of the simplicial manifold vary continuously and the Z_2-Regge Model where they are restricted to two possible values. The goal is to determine whether the computationally more easily accessible Z_2 model still retains the universal characteristics of standard Regge theory in two dimensions. In order to compare observables such as average curvature or Liouville field susceptibility, we use in both models the same functional integration measure, which is chosen to render the Z_2-Regge Model particularly simple. Expectation values are computed numerically and agree qualitatively for positive bare couplings. The phase transition within the Z_2-Regge Model is analyzed by mean-field theory.Comment: 21 pages, 16 ps-figures, to be published in Phys. Rev.
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