903 research outputs found

    Lattice Boltzmann scheme for relativistic fluids

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    A Lattice Boltzmann formulation for relativistic fluids is presented and numerically verified through quantitative comparison with recent hydrodynamic simulations of relativistic shock-wave propagation in viscous quark-gluon plasmas. This formulation opens up the possibility of exporting the main advantages of Lattice Boltzmann methods to the relativistic context, which seems particularly useful for the simulation of relativistic fluids in complicated geometries.Comment: Submitted to PR

    Pattern formation from consistent dynamical closures of uniaxial nematic liquid crystals

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    Pattern formation in uniaxial polymeric liquid crystals is studied for different dynamic closure approximations. Using the principles of mesoscopic non-equilibrium thermodynamics in a mean-field approach, we derive a Fokker-Planck equation for the single-particle non-homogeneous distribution function of particle orientations and the evolution equations for the second and fourth order orientational tensor parameters. Afterwards, two dynamic closure approximations are discussed, one of them considering the relaxation of the fourth order orientational parameter and leading to a novel expression for the free-energy like function in terms of the scalar order parameter. Considering the evolution equation of the density of the system and values of the interaction parameter for which isotropic and nematic phases coexist, our analysis predicts that patterns and traveling waves can be produced in lyotropic uniaxial nematics even in the absence of external driving.Comment: 34 pages, 7 figure

    Quality parameters and technological properties of pasta enriched with a fish by-product: A healthy novel food

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    The effect of incorporating a fish (D. labrax) by-product on pasta quality was evaluated to assess its technological viability in comparison with a common pasta. Two enriched pastas, both dried and fresh and including or not a natural antioxidant (R. officinalis) were analyzed and compared to traditional pasta (durum and spelt). Findings indicated that enriched pasta showed a decrease in their texture properties, except for adhesiveness which was higher compared to traditional pasta. The addition of fish caused slight changes in color. Regarding the technological quality, it was moderately affected by fish inclusion, presenting lower gains in weight respect to control pasta (>15% of difference). Therefore, enriched pasta appears to be a good alternative to offer food with an improved nutritional profile with a low impact on the quality of the product from a technological point of view since the introduction of fish does not extensively affect pasta quality. Novelty impact statement: The enrichment of pasta from fish by-product is a good alternative to improve its nutritional value. The cooking had a beneficial effect on the bioavailability of nutrients in enriched pasta with fish. Technological properties of enriched pasta with fish after cooking was similar to traditional pasta made with durum wheat. © 2021 The Authors. Journal of Food Processing and Preservation published by Wiley Periodicals LLC

    Pathogenicity and fusaric acid production by fusarium proliferatum isolated from garlic in Spain

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    Fusarium proliferatum has been reported on garlic in the north west U.S.A., Spain and Serbia, causing as water-soaked tan lesions on cloves. Moreover, F. proliferatum is known to produce a range of toxins, including fumonisin B1, moniliformin, beauvericin, fusaproliferin and fusaric acid, which are implicated in pathogenesis. In this study six randomly selected F. proliferatum isolates from garlic were tested for pathogenicity and screened for fusaric acid production. Healthy seedlings of onion (Allium cepa), leek (A. porrum) and chives (A. schoenoprasum) and garlic clones (A. sativum) were inoculated. Onion seedlings and garlic clones were soaked in the conidial suspensions of each F. proliferatum isolate for 24 h and then planted in flats containing soil previously inoculated with the same isolate of F. proliferatum. Plants were maintained in a temperature and light-controlled greenhouse (12 h/12 h light/dark; 25/21°C). The root and bulb/clove rot disease symptoms were graded into five classes following the method of Stankovick et al. (2007). A disease severity index (DSI) was calculated as the mean of three plants of each species and four test replicates. Symptoms on onion and garlic plants were observed three weeks after inoculation. The overall effects of isolate, host and variety were analyzed. Effects were significant for all the studied isolates. The correlations between isolate pathogenicity and production of FA are also discussed

    Characterization of the spoilage microbiota of hake fillets packaged under a modified atmosphere (MAP) rich in CO2 (50% CO2/50% N2) and stored at different temperatures

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    The aim of this study was to characterize the spoilage microbiota of hake fillets stored under modified atmospheres (MAP) (50% CO2/50% N2) at different temperatures using high-throughput 16S rRNA gene sequencing and to compare the results with those obtained using traditional microbiology techniques. The results obtained indicate that, as expected, higher storage temperatures lead to shorter shelf-lives (the time of sensory rejection by panelists). Thus, the shelf-life decreased from six days to two days for Batch A when the storage temperature increased from 1 to 7 °C, and from five to two days—when the same increase in storage temperature was compared—for Batch B. In all cases, the trimethylamine (TMA) levels measured at the time of sensory rejection of hake fillets exceeded the recommended threshold of 5 mg/100 g. Photobacterium and Psychrobacter were the most abundant genera at the time of spoilage in all but one of the samples analyzed: Thus, Photobacterium represented between 19% and 46%, and Psychrobacter between 27% and 38% of the total microbiota. They were followed by Moritella, Carnobacterium, Shewanella, and Vibrio, whose relative order varied depending on the sample/batch analyzed. These results highlight the relevance of Photobacterium as a spoiler of hake stored in atmospheres rich in CO2. Further research will be required to elucidate if other microorganisms, such as Psychrobacter, Moritella, or Carnobacterium, also contribute to spoilage of hake when stored under MAP

    Intensity-field correlation of single-atom resonance fluorescence

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    We report measurements of an intensity-field correlation function of the resonance fluorescence of a single trapped Ba+ ion. Detection of a photon prepares the atom in its ground state and we observe its subsequent evolution under interaction with a laser field of well defined phase. We record the regression of the resonance fluorescence source field. This provides a direct measurement of the field of the radiating dipole of a single atom and exhibits its strong non-classical behavior. In the experimental setup an interference measurement is conditioned on a fluorescence photon detection. The third-order correlation function thus recorded demonstrates an aspect of wave-particle duality at the single-atom, single-photon level.Comment: 4 pages, 4 figures, accepted in PR

    Fusarium proliferatum isolated from garlic in Spain: Identification, toxigenic potential and pathogenicity on related Allium species

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    Fusarium proliferatum has been reported on garlic in the Northwest USA, Spain and Serbia, causing water-soaked tan-colored lesions on cloves. In this work, Fusarium proliferatum was isolated from 300 symptomatic garlic bulbs. Morphological identification of Fusarium was confirmed using species-specific PCR assays and EF-1α sequencing. Confirmation of pathogenicity was conducted with eighteen isolates. Six randomly selected F. proliferatum isolates from garlic were tested for specific pathogenicity and screened for fusaric acid production. Additionally, pathogenicity of each F. proliferatum isolate was tested on healthy seedlings of onion (Allium cepa), leek (A. porrum), scallions (A. fistulosum), chives (A. schoenoprasum) and garlic (A. sativum). A disease severity index (DSI) was calculated as the mean severity on three plants of each species with four test replicates. Symptoms on onion and garlic plants were observed three weeks after inoculation. All isolates tested produced symptoms on all varieties inoculated. Inoculation of F. proliferatum isolates from diseased garlic onto other Allium species provided new information on host range and pathogenicity. The results demonstrated differences in susceptibility with respect to host species and cultivar. The F. proliferatum isolates tested all produced fusaric acid (FA); correlations between FA production and isolate pathogenicity are discussed. Additionally, all isolates showed the presence of the FUM1 gene suggesting the ability of Spanish isolates to produce fumonisins
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