156 research outputs found

    Tibetan sheep are better able to cope with low energy intake than Small-tailed Han sheep due to lower maintenance energy requirements and higher nutrient digestibilities

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    Tibetan sheep are indigenous to the Qinghai-Tibetan Plateau (QTP) and are well-adapted to and even thrive under the harsh alpine conditions. Small-tailed Han sheep were introduced to the plateau because of their high prolificacy and are maintained mainly in feedlots. Because of their different backgrounds, we hypothesised that Tibetan and Small-tailed Han sheep would differ in their utilization of energy intake and predicted that Tibetan sheep would cope better with low energy intake than Small-tailed Han sheep. To test this prediction, we determined nutrient digestibilities, energy requirements for maintenance and blood metabolite and hormone concentrations involved in energy metabolism in these breeds. Sheep of each breed (n = 24 of each, all wethers and 1.5 years of age) were distributed randomly into one of four groups and offered ad libitum diets of different digestible energy (DE) densities: 8.21, 9.33, 10.45 and 11.57 MJ DE/kg Dry matter (DM). Following 42 d of measuring feed intake, a 1-week digestion and metabolism experiment was done. DM intakes did not differ between breeds nor among treatments but, by design, DE intake increased linearly in both breeds as dietary energy level increased (P < 0.001). The average daily gain (ADG) was significantly greater in the Tibetan than Small-tailed Han sheep (P = 0.003) and increased linearly in both breeds (P < 0.001). In addition, from the regression analysis of ADG on DE intake, daily DE maintenance requirements were lower for Tibetan than for Small-tailed Han sheep (0.41 vs 0.50 MJ/BW0.75, P < 0.05). The DE and metabolizable energy (ME) digestibilities were higher in the Tibetan than Small-tailed Han sheep (P < 0.001) and increased linearly as the energy level increased in the diet (P < 0.001). At the lowest energy treatment, Tibetan sheep when compared with Small-tailed Han sheep, had: 1) higher serum glucose and glucagon, but lower insulin concentrations (P < 0.05), which indicated a higher capacity for gluconeogenesis and ability to regulate glucose metabolism; and 2) higher non-esterified fatty acids (NEFA) and lower very low density lipoprotein (VLDL) and triglyceride (TG) concentrations (P < 0.05), which indicated a higher capacity for NEFA oxidation but lower ability for triglyceride (TG) synthesis. We concluded that our prediction was supported as these differences between breeds conferred an advantage for Tibetan over Small-tailed Han sheep to cope better with low energy diets

    Exact Results on Potts Model Partition Functions in a Generalized External Field and Weighted-Set Graph Colorings

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    We present exact results on the partition function of the qq-state Potts model on various families of graphs GG in a generalized external magnetic field that favors or disfavors spin values in a subset Is={1,...,s}I_s = \{1,...,s\} of the total set of possible spin values, Z(G,q,s,v,w)Z(G,q,s,v,w), where vv and ww are temperature- and field-dependent Boltzmann variables. We remark on differences in thermodynamic behavior between our model with a generalized external magnetic field and the Potts model with a conventional magnetic field that favors or disfavors a single spin value. Exact results are also given for the interesting special case of the zero-temperature Potts antiferromagnet, corresponding to a set-weighted chromatic polynomial Ph(G,q,s,w)Ph(G,q,s,w) that counts the number of colorings of the vertices of GG subject to the condition that colors of adjacent vertices are different, with a weighting ww that favors or disfavors colors in the interval IsI_s. We derive powerful new upper and lower bounds on Z(G,q,s,v,w)Z(G,q,s,v,w) for the ferromagnetic case in terms of zero-field Potts partition functions with certain transformed arguments. We also prove general inequalities for Z(G,q,s,v,w)Z(G,q,s,v,w) on different families of tree graphs. As part of our analysis, we elucidate how the field-dependent Potts partition function and weighted-set chromatic polynomial distinguish, respectively, between Tutte-equivalent and chromatically equivalent pairs of graphs.Comment: 39 pages, 1 figur

    Ultra-sharp asymmetric Fano-like resonance spectrum on Si photonic platform

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    In this paper, we report the generation of an ultra-sharp asymmetric resonance spectrum through Fano-like interference. This generation is accomplished by weakly coupling a high-quality factor (Q factor) Fabry–Pérot (FP) cavity and a low-Q factor FP cavity through evanescent waves. The high-Q FP cavity is formed by Sagnac loop mirrors, whilst the low-Q one is built by partially transmitting Sagnac loop reflectors. The working principle has been analytically established and numerically modelled by using temporal coupled-mode-theory (CMT), and verified using a prototype device fabricated on the 340 nm silicon-on-insulator (SOI) platform, patterned by deep ultraviolet (DUV) lithography. Pronounced asymmetric resonances with slopes up to 0.77 dB/pm have been successfully measured, which, to the best of our knowledge, is higher than the results reported in state-of-the-art devices in on-chip integrated Si photonic studies. The established theoretical analysis method can provide excellent design guidelines for devices with Fano-like resonances. The design principle can be applied to ultra-sensitive sensing, ultra-high extinction ratio switching, and more applications

    Production of Υ(nS) mesons in Pb+Pb and pp collisions at 5.02 TeV

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    A measurement of the production of vector bottomonium states, Υ ( 1S ) , Υ ( 2S ) , and Υ ( 3S ) , in Pb + Pb and p p collisions at a center-of-mass energy per nucleon pair of 5.02 TeV is presented. The data correspond to integrated luminosities of 1.38 nb − 1 of Pb + Pb data collected in 2018, 0.44 nb − 1 of Pb + Pb data collected in 2015, and 0.26 fb − 1 of p p data collected in 2017 by the ATLAS detector at the Large Hadron Collider. The measurements are performed in the dimuon decay channel for transverse momentum p μ μ T &lt; 30 GeV , absolute rapidity | y μ μ | &lt; 1.5 , and Pb + Pb event centrality 0–80%. The production rates of the three bottomonium states in Pb + Pb collisions are compared with those in p p collisions to extract the nuclear modification factors as functions of event centrality, p μ μ T , and | y μ μ | . In addition, the suppression of the excited states relative to the ground state is studied. The results are compared with theoretical model calculations

    Method for finding roots of quartic equation with application to RS codes

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    Electronics Letters34252399-2400ELLE

    Repair of multi-layered, polymer-based thermal spray coatings

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    Polymeric coatings manufactured by thermal spray processes exhibit variable mechanical and adhesion properties that depend on their exact processing schedules. One important advantage of these coatings is that they can be readily repaired by re-spraying any delaminated or otherwise defective regions. In some instances the repaired region exhibits better mechanical attributes than the original coating. In this study the repairability of several classes of polymeric and polymer-ceramic composite coatings were investigated with a focus on the interfacial adhesion properties. The coatings include those of monolayer and bilayer ethylene methacrylic acid (EMAA), and CaC03-EMAA composites. The coating thickness did not influence the interfacial adhesive strength between the coating and substrate; while a higher preheat temperature produced a greater interfacial cohesion for the monolayer coating on a metal substrate. The substrate preheat temperature played a dominant role concerning the peel strength of the coating. Greater peel strengths were achieved between polymers, at least twofold greater than that between the polymer and the steel substrate when the pre-heat temperature was greater than the melting point of the polymer. The peel strength of the composite coating decreased with filler content; both on the steel substrate and on a previously sprayed polymer coating. On the basis of these observations, the adhesion mechanism between polymers was explained with a model that relied on the formation of welding points

    Preparation and performance of a novel multifunctional plasma electrolytic oxidation composite coating formed on magnesium alloy

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    Plasma electrolytic oxidation (PEO) in an alkaline phosphate electrolyte was used to produce a novel multifunctional polytetrafluoroethylene (PTFE)-containing oxide composite coatings on AM60B magnesium alloys. The composition and microstructure of the PTFE-containing PEO coatings were analyzed by X-ray photoelectron spectroscope (XPS), X-ray diffraction (XRD), and scanning electron microscope (SEM). The electrochemical corrosion behavior, tribological properties, and wetting properties of the PTFE-containing PEO composite coatings were evaluated using potentiodynamic polarization measurements, a reciprocating ball-on-disk tribometer, and a contact angle meter, respectively. Results show that the PTFE-containing PEO composite coatings exhibited superior corrosion resistance, excellent self-lubricating property, and better hydrophobic property when compared with pure PEO coatings, and will be the attractive advanced materials for a wide range of functional applications
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