243 research outputs found

    Ruminal Fill Effect of Forages: Prediction and Relationship with Voluntary Intake

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    Voluntary dry matter intake (VDMI) and rumen fill were measured on sheep fed with 18 forages ranging from wheat straw to lucerne hay. In vivo fill effect (IVFE i.e. rumen DM pool divided by VDMI), in situ degradability, cell-wall composition, pepsin-cellulase digestibility and in vitro gas production were determined. In situ estimated fill effect (ISFE) was calculated as the retention time of insoluble potential degradable and undegradable fractions using a constant rate of passage. ISFE and IVFE were highly correlated (r2=0.89) but ISFE values were lower than IVFE values because in situ degradability does not integrate comminution time of large particles. NDF content, pepsin-cellulase digestibility and gas production were good predictors of IVFE (r2=0.86, 0.90 and 0.91 respectively) and to a lesser extent of VDMI (r2=0.78, 0.88 and 0.84)

    Patterns of Localisation in the French Manufacturing and Service Industries: a Distance-Based Approach

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    We explore the patterns of localisation in the French manufacturing and service industries using the distance-based approach developed by Duranton and Overman (2005). The idea of this methodology is to consider the distribution of distances between pairs of plants in an industry and to compare it with that of a hypothetical industry with the same number of plants which are randomly distributed conditional on the distribution of aggregate activity. Relying on the same industrial classification as the one used by these authors, we show that their main conclusions remain valid in the case of French manufacturing industries. First, fewer manufacturing industries are found to be globally localised than usually found with discrete indices (Ellison-Glaeser, Maurel-SĂ©dillot). Second, localisation takes place at small distance (localisation, K-density, spatial statistics, point-pattern processes

    Analytic continuation of residue currents

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    Let XX be a complex manifold and f\colon X\to \C^p a holomorphic mapping defining a complete intersection. We prove that the iterated Mellin transform of the residue integral associated to ff has an analytic continuation to a neighborhood of the origin in \C^p

    Differential Forms on Log Canonical Spaces

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    The present paper is concerned with differential forms on log canonical varieties. It is shown that any p-form defined on the smooth locus of a variety with canonical or klt singularities extends regularly to any resolution of singularities. In fact, a much more general theorem for log canonical pairs is established. The proof relies on vanishing theorems for log canonical varieties and on methods of the minimal model program. In addition, a theory of differential forms on dlt pairs is developed. It is shown that many of the fundamental theorems and techniques known for sheaves of logarithmic differentials on smooth varieties also hold in the dlt setting. Immediate applications include the existence of a pull-back map for reflexive differentials, generalisations of Bogomolov-Sommese type vanishing results, and a positive answer to the Lipman-Zariski conjecture for klt spaces.Comment: 72 pages, 6 figures. A shortened version of this paper has appeared in Publications math\'ematiques de l'IH\'ES. The final publication is available at http://www.springerlink.co

    Cement degradation in CO2 storage sites: a review on potential applications of nanomaterials

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    © 2018 The Author(s) Carbon capture and sequestration (CCS) has been employed to reduce global warming, which is one of the critical environmental issues gained the attention of scientific and industrial communities worldwide. Once implemented successfully, CCS can store at least 5 billion tons of CO2per year as an effective and technologically safe method. However, there have been a few issues raised in recent years, indicating the potential leakages paths created during and after injection. One of the major issues might be the chemical interaction of supercritical CO2with the cement, which may lead to the partial or total loss of the cement sheath. There have been many approaches presented to improve the physical and mechanical properties of the cement against CO2attack such as changing the water-to-cement ratio, employing pozzolanic materials, and considering non-Portland cements. However, a limited success has been reported to the application of these approaches once implemented in a real-field condition. To date, only a few studies reported the application of nanoparticles as sophisticated additives which can reinforce oil well cements. This paper provides a review on the possible application of nanomaterials in the cement industry where physical and mechanical characteristics of the cement can be modified to have a better resistance against corrosive environments such as CO2storage sites. The results obtained indicated that adding 0.5 wt% of Carbon NanoTubes (CNTs) and NanoGlass Flakes (NGFs) can reinforce the thermal stability and coating characteristics of the cement which are required to increase the chance of survival in a CO2sequestrated site. Nanosilica can also be a good choice and added to the cement by as much as 3.0 wt% to improve pozzolanic reactivity and thermal stability as per the reports of recent studies

    Over-expression of adenosine deaminase in mouse podocytes does not reverse puromycin aminonucleoside resistance

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    <p>Abstract</p> <p>Background</p> <p>Edema in nephrotic syndrome results from renal retention of sodium and alteration of the permeability properties of capillaries. Nephrotic syndrome induced by puromycin aminonucleoside (PAN) in rats reproduces the biological and clinical signs of the human disease, and has been widely used to identify the cellular mechanisms of sodium retention. Unfortunately, mice do not develop nephrotic syndrome in response to PAN, and we still lack a good mouse model of the disease in which the genetic tools necessary for further characterizing the pathophysiological pathway could be used. Mouse resistance to PAN has been attributed to a defect in glomerular adenosine deaminase (ADA), which metabolizes PAN. We therefore attempted to develop a mouse line sensitive to PAN through induction of normal adenosine metabolism in their podocytes.</p> <p>Methods</p> <p>A mouse line expressing functional ADA under the control of the podocyte-specific podocin promoter was generated by transgenesis. The effect of PAN on urinary excretion of sodium and proteins was compared in rats and in mice over-expressing ADA and in littermates.</p> <p>Results</p> <p>We confirmed that expression of ADA mRNAs was much lower in wild type mouse than in rat glomerulus. Transgenic mice expressed ADA specifically in the glomerulus, and their ADA activity was of the same order of magnitude as in rats. Nonetheless, ADA transgenic mice remained insensitive to PAN treatment in terms of both proteinuria and sodium retention.</p> <p>Conclusions</p> <p>Along with previous results, this study shows that adenosine deaminase is necessary but not sufficient to confer PAN sensitivity to podocytes. ADA transgenic mice could be used as a background strain for further transgenesis.</p

    Transcriptional Responses of Arabidopsis thaliana during Wilt Disease Caused by the Soil-Borne Phytopathogenic Bacterium, Ralstonia solanacearum

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    Bacterial wilt is a common disease that causes severe yield and quality losses in many plants. In the present study, we used the model Ralstonia solanacearum-Arabidopsis thaliana pathosystem to study transcriptional changes associated with wilt disease development. Susceptible Col-5 plants and RRS1-R-containing resistant Nd-1 plants were root-inoculated with R. solanacearum strains harbouring or lacking the matching PopP2 avirulence gene. Gene expression was marginally affected in leaves during the early stages of infection. Major changes in transcript levels took place between 4 and 5 days after pathogen inoculation, at the onset of appearance of wilt symptoms. Up-regulated genes in diseased plants included ABA-, senescence- and basal resistance-associated genes. The influence of the plant genetic background on disease-associated gene expression is weak although some genes appeared to be specifically up-regulated in Nd-1 plants. Inactivation of some disease-associated genes led to alterations in the plant responses to a virulent strain of the pathogen. In contrast to other pathosystems, very little overlap in gene expression was detected between the early phases of the resistance response and the late stages of disease development. This observation may be explained by the fact that above-ground tissues were sampled for profiling whereas the bacteria were applied to root tissues
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