1,144 research outputs found

    Methods of isolation and identification of pathogenic and potential pathogenic bacteria from skins and tannery effluents

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    Currently there is no standard protocol available within the leather industry to isolate and identify pathogenic bacteria from hides, skins or tannery effluent. This study was therefore carried out to identify simple but effective methods for isolation and identification of bacterial pathogens from the effluent and skins during leather processing. Identification methods based on both phenotypic and genotypic characteristics were investigated. Bacillus cereus and Pseudomonas aeruginosa were used as indicator bacteria to evaluate the isolation and identification methods. Decontaminated calfskins were inoculated with a pure culture of the above mentioned bacterial species followed by a pre-tanning and chromium tanning processes. Effluent samples were collected and skins were swabbed at the end of each processing stage. Bacterial identification was carried out based on the phenotypic characteristics; such as colony appearance on selective solid media, cell morphology following a standard Gram-staining and spore staining techniques, and biochemical reactions, e.g., the ability of a bacterial species to ferment particular sugars and ability to produce certain enzymes. Additionally, an identification system based on bacterial phenotypic characteristics, known as Biolog® system was applied. A pulsed-filed gel electrophoresis (PFGE) method for bacterial DNA fingerprinting was also evaluated and used for the identification of the inoculated bacteria. The methods described in the study were found to be effective for the identification of pathogenic bacteria from skins and effluent

    Discretization-related issues in the KPZ equation: Consistency, Galilean-invariance violation, and fluctuation--dissipation relation

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    In order to perform numerical simulations of the KPZ equation, in any dimensionality, a spatial discretization scheme must be prescribed. The known fact that the KPZ equation can be obtained as a result of a Hopf--Cole transformation applied to a diffusion equation (with \emph{multiplicative} noise) is shown here to strongly restrict the arbitrariness in the choice of spatial discretization schemes. On one hand, the discretization prescriptions for the Laplacian and the nonlinear (KPZ) term cannot be independently chosen. On the other hand, since the discretization is an operation performed on \emph{space} and the Hopf--Cole transformation is \emph{local} both in space and time, the former should be the same regardless of the field to which it is applied. It is shown that whereas some discretization schemes pass both consistency tests, known examples in the literature do not. The requirement of consistency for the discretization of Lyapunov functionals is argued to be a natural and safe starting point in choosing spatial discretization schemes. We also analyze the relation between real-space and pseudo-spectral discrete representations. In addition we discuss the relevance of the Galilean invariance violation in these consistent discretization schemes, and the alleged conflict of standard discretization with the fluctuation--dissipation theorem, peculiar of 1D.Comment: RevTex, 23pgs, 2 figures, submitted to Phys. Rev.

    Fish Welfare in Urban Aquaponics: Effects of Fertilizer for Lettuce (Lactuca sativa L.) on Some Physiological Stress Indicators in Nile Tilapia (Oreochromis niloticus L.)

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    The combination of hydroponics and aquaculture, or aquaponics, normally requires adding fertilizer to recirculated water to ensure optimal plant growth, but the effect of that fertilizer on fish welfare has not been studied in detail, especially for small urban and coupled aquaponic systems. In this study, a commercial fertilizer was placed in two small aquaponic systems (less than 250 liters each) to test its effect on the stress levels of Nile tilapia (Oreochromis niloticus) compared to controls without any fertilizer. Fish production parameters were not significantly different between treatments, nor were physiological indicators of fish stress (plasma cortisol, glucose, and triglycerides). On the other hand, lettuce growth (leaf and root weight and length) was up to three times higher in the treatment that received fertilizer. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

    Economic dynamics with financial fragility and mean-field interaction: a model

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    Following the statistical mechanics methodology, firstly introduced in macroeconomics by Aoki [1996,2002], we provide some insights to the well known works of Greenwald and Stiglitz [1990, 1993]. Specifically, we reach analytically a closed form solution of their models overcoming the aggregation problem. The key idea is to represent the economy as an evolving complex system, composed by heterogeneous interacting agents, that can partitioned into a space of macroscopic states. This meso level of aggregation permits to adopt mean field interaction modeling and master equation techniques.Comment: APFA6 proceeding

    Cardioprotective Effects of Taurisolo® in Cardiomyoblast H9c2 Cells under High-Glucose and Trimethylamine N-Oxide Treatment via de Novo Sphingolipid Synthesis

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    In addition to high plasma glucose, increased levels of trimethylamine N-oxide (TMAO) have been found in obese subjects, where are considered as a novel risk factor for cardiovascular diseases. The present study aimed to investigate the effect of a novel nutraceutical formulation based on grape polyphenols (registered as Taurisolo®) in counteracting TMAO- and high glucose (HG)-induced cytotoxicity in cardiomyoblast H9c2 cells. Cell damage was induced with HG (HG-H9c2) and HG+TMAO (THG-H9c2); both experimental cell models were, thus, incubated for 72 h in the presence or absence of Taurisolo®. It was observed that Taurisolo® significantly increased the cell viability and reduced lactate dehydrogenase and aspartate transaminase release in both HG- and THG-H9c2 cells. Additionally, through its antioxidant activity, Taurisolo® modulated cell proliferation via ERK activation in THG-H9c2. Furthermore, Taurisolo® was able to induce autophagic process via increasing the expression of LC3II, a protein marker involved in formation of autophagosome and ex novo synthesis of sphingomyelin, ceramides, and their metabolites both in HG- and THG-H9c2 cells. Finally, Taurisolo® reduced hypertrophy and induced differentiation of HG-H9C2 cells into cardiomyocyte-like cells. These data suggest that Taurisolo® counteracts the toxicity induced by TMAO and HG concentrations increasing autophagic process and activating de novo sphingolipid synthesis, resulting in a morphological cell remodeling. In conclusion, our results allow speculating that Taurisolo®, combined with energy restriction, may represent a useful nutraceutical approach for prevention of cardiomyopathy in obese subjects

    Optimal Uncertainty Quantification

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    We propose a rigorous framework for Uncertainty Quantification (UQ) in which the UQ objectives and the assumptions/information set are brought to the forefront. This framework, which we call \emph{Optimal Uncertainty Quantification} (OUQ), is based on the observation that, given a set of assumptions and information about the problem, there exist optimal bounds on uncertainties: these are obtained as values of well-defined optimization problems corresponding to extremizing probabilities of failure, or of deviations, subject to the constraints imposed by the scenarios compatible with the assumptions and information. In particular, this framework does not implicitly impose inappropriate assumptions, nor does it repudiate relevant information. Although OUQ optimization problems are extremely large, we show that under general conditions they have finite-dimensional reductions. As an application, we develop \emph{Optimal Concentration Inequalities} (OCI) of Hoeffding and McDiarmid type. Surprisingly, these results show that uncertainties in input parameters, which propagate to output uncertainties in the classical sensitivity analysis paradigm, may fail to do so if the transfer functions (or probability distributions) are imperfectly known. We show how, for hierarchical structures, this phenomenon may lead to the non-propagation of uncertainties or information across scales. In addition, a general algorithmic framework is developed for OUQ and is tested on the Caltech surrogate model for hypervelocity impact and on the seismic safety assessment of truss structures, suggesting the feasibility of the framework for important complex systems. The introduction of this paper provides both an overview of the paper and a self-contained mini-tutorial about basic concepts and issues of UQ.Comment: 90 pages. Accepted for publication in SIAM Review (Expository Research Papers). See SIAM Review for higher quality figure

    Influence of temperament on performance and carcass quality of commercial Brahman steers in a Colombian tropical grazing system

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    Temperament is defined as individual behavioral responses to potentially fear-eliciting or challenging situations related to human presence and handling. A total of 190 steers of commercial Zebu Brahman (Bos indicus) were used in this study, selected when they were between 10 and 11 months of age, fattened for 24 months (720 days) and slaughtered between 34 and 35 months of age. Using a temperament index (based on two tests: chute and exit score), animals were classified as calm, restless, or nervous. In general, calm animals had a longer carcass, a higher slaughter and fasting weight, and a normal pH24 (<5.7). However, carcass yield was significantly higher in nervous than in restless animals, but did not differ from that of calm steers. It is important to note that these results were obtained under experimental conditions, therefore, effects could have a greater impact on carcass quality under commercial conditions. © 2022 The Author

    Genetic Dissection of Complex Fruit Quantitative Traits in Peach Progen

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    Major research efforts in peach are dedicated to the discovery of genomic variants causing phenotypic effects in complex fruit traits such as: maturity date (MD), fruit size (FW), sugar (SSC) and acid content (TA), flesh texture (slow softening, SSf) and resistance to brown rot by Monilinia spp. (BRr). Five segregating progenies showing phenotypic variation for at least one of these traits are available in our experimental fields. For SSC and TA, an already validated approach based on Near-InfraRed spectroscopy (NIR), is being applied to phenotype some segregating progenies. For SSf and BRr instead, trait characterization has been performed, resulting in the identification of co-factor traits and definition of standardized phenotyping tools, which are currently applied in the characterization of segregating material (in the context of FruitBreedomics EU project). High-density linkage maps have been constructed with genotypic data obtained from IPSC Illumina 9K SNP chip (Italian Drupomics and FruitBreedomics frameworks) and Genotyping-by-Sequencing (GBS). Additionally, parents of these progenies have been re-sequenced (30-40x) and genetic variants present along their genomes have been identified. Multiple-QTL models (MQM) coupled with the use of co-factor traits is leading to the discovery of significant QTLs. Genomic variants are explored within QTL intervals on the genomes of progeny parents, in order to identify possible mutations causing phenotypic differences, and develop markers for marker-assisted selection approaches
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