2,148 research outputs found

    Potential dietary feed additives with antibacterial effects and their impact on performance of weaned piglets: A meta-analysis

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    This meta-analysis evaluated the use of potential dietary feed additives (pDFA) with antibacterial effects and their impact on the perfomance of weaned piglets. Twenty-three peer-reviewed in vivo studies, comprising 50 trials, were identified between January 2010 and January 2017. The pDFA in these studies could be grouped in 5 classes: antimicrobial peptides, chitosan, lysozyme, medium chain fatty acids/ triglycerides and plant extracts. Mixed-effect meta-analyses with type of pDFA as fixed effect were performed for the growth parameters ‘average daily gain’ (ADG) and ‘feed conversion ratio’ (FCR), which are the two most important and used economic performance parameters for farmers. For each class of pDFA, results of the meta-analysis showed significantly higher average daily gain in the group with pDFA compared to the negative control group, while no significant difference with the positive control group was observed. Furthermore, a positive effect on FCR was found, i.e. significantly less feed was needed to gain 1 kg of body weight in the group with pDFA compared to the negative control group. No significant differences with positive control groups were observed for each class of pDFA, except for plant extracts, where the FCR was also significantly reduced in the treatment group. These results suggest that pDFA could reduce the use of antimicrobials without significant negative effects on performance indicators

    Potential dietary feed additives with antibacterial effects and their impact on performance of weaned piglets : a meta-analysis

    Get PDF
    This meta-analysis evaluated the use of potential dietary feed additives (pDFA) with antibacterial effects and their impact on the perfomance of weaned piglets. Twenty-three peer-reviewed in vivo studies, comprising 50 trials, were identified between January 2010 and January 2017. The pDFA in these studies could be grouped in 5 classes: antimicrobial peptides, chitosan, lysozyme, medium chain fatty acids/triglycerides and plant extracts. Mixed-effect meta-analyses with type of pDFA as fixed effect were performed for the growth parameters 'average daily gain' (ADG) and 'feed conversion ratio' (FCR), which are the two most important and used economic performance parameters for farmers. For each class of pDFA, results of the meta-analysis showed significantly higher average daily gain in the group with pDFA compared to the negative control group, while no significant difference with the positive control group was observed. Furthermore, a positive effect on FCR was found, i.e. significantly less feed was needed to gain 1 kg of body weight in the group with pDFA compared to the negative control group. No significant differences with positive control groups were observed for each class of pDFA, except for plant extracts, where the FCR was also significantly reduced in the treatment group. These results suggest that pDFA could reduce the use of antimicrobials without significant negative effects on performance indicators

    Optical properties of tungsten thin films perforated with a bidimensional array of subwavelength holes

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    We present a theorical investigation of the optical transmission of a dielectric grating carved in a tungsten layer. For appropriate wavelengths tungsten shows indeed a dielectric behaviour. Our numerical simulations leads to theoretical results similar to those found with metallic systems studied in earlier works. The interpretation of our results rests on the idea that the transmission is correlated with the resonant response of eigenmodes coupled to evanescent diffraction orders.Comment: 4 pages, 3 figure

    Relation between hospital orthopaedic specialisation and outcomes in patients aged 65 and older: retrospective analysis of US Medicare data

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    Objective To explore the relation between hospital orthopaedic specialisation and postoperative outcomes after total hip or knee replacement surgery

    Brane matter, hidden or mirror matter, their various avatars and mixings: many faces of the same physics

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    Numerous papers deal with the phenomenology related to photon-hidden photon kinetic mixing and with the effects of a mass mixing on particle-hidden particle oscillations. In addition, recent papers underline the existence of a geometrical mixing between branes which would allow a matter swapping between branes. These approaches and their phenomenologies are reminiscent of each other but rely on different physical concepts. In the present paper, we suggest there is no rivalry between these models, which are probably many faces of the same physics. We discuss some phenomenological consequences of a global framework.Comment: 9 pages. Typo corrected. Published in European Physical Journal

    Exciton swapping in a twisted graphene bilayer as a solid-state realization of a two-brane model

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    It is shown that exciton swapping between two graphene sheets may occur under specific conditions. A magnetically tunable optical filter is described to demonstrate this new effect. Mathematically, it is shown that two turbostratic graphene layers can be described as a "noncommutative" two-sheeted (2+1)-spacetime thanks to a formalism previously introduced for the study of braneworlds in high energy physics. The Hamiltonian of the model contains a coupling term connecting the two layers which is similar to the coupling existing between two braneworlds at a quantum level. In the present case, this term is related to a K-K' intervalley coupling. In addition, the experimental observation of this effect could be a way to assess the relevance of some theoretical concepts of the braneworld hypothesis.Comment: 15 pages, 3 figures, final version published in European Physical Journal

    Optical structure and function of the white filamentary hair covering the edelweiss bracts

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    The optical properties of the inflorescence of the high-altitude ''Leontopodium nivale'' subsp. ''alpinum'' (edelweiss) is investigated, in relation with its submicrometer structure, as determined by scanning electron microscopy. The filaments forming the hair layer have been found to exhibit an internal structure which may be one of the few examples of a photonic structure found in a plant. Measurements of light transmission through a self-supported layer of hair pads taken from the bracts supports the idea that the wooly layer covering the plant absorbs near-ultraviolet radiation before it reaches the cellular tissue. Calculations based on a photonic-crystal model provides insight on the way radiation can be absorbed by the filamentary threads.Comment: 9 pages, 13 figures. Published pape
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