6,294 research outputs found

    Settleability assessment protocol for anaerobic granular sludge and its application

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    A simple method for settleability assessment of anaerobic granular sludge was proposed and its applicability as an opera parameter was evaluated in a lab-scale UASB reactor treating brewery wastewater. Based on the settleability protocol, the O was increased up to 28 kg COD.m-3.d-1 (67 kg COD.m-3 of granular bed volume.d-1) which corresponds to an HRT of 1 h. The re revealed that the protocol was sufficiently sensitive to define the settleability of the sludge samples and to accurately determ their allowable upflow velocities, resultant organic loading rates, and recycling ratios according to the settleability of the gran bed. Also, a series of graphical procedures with settling tests which are very easy to apply for settleability monitoring improvised, capable of direct use as an operational and monitoring parameter of the granular bed with laboratory and full-scale reactors, without need for additional sludge bed control such as dosing of chemicals. In addition, this method was also found to be applicable to improve and monitor system performance according to high or low-strength wastewater characteristics. Image analysis of the granular biomass supported the suitability of this graphical method. WaterSA Vol.29(4) 2003: 419-42

    Duality of Quasilocal Black Hole Thermodynamics

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    We consider T-duality of the quasilocal black hole thermodynamics for the three-dimensional low energy effective string theory. Quasilocal thermodynamic variables in the first law are explicitly calculated on a general axisymmetric three-dimensional black hole solution and corresponding dual one. Physical meaning of the dual invariance of the black hole entropy is considered in terms of the Euclidean path integral formulation.Comment: 19 pages, Latex, no figures, to be published in Class. Quantum Grav. Some minor changes, references adde

    A New SX Phe Star in the Globular Cluster M15

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    A new SX Phe star (labelled SXP1) found from BVBV CCD photometry is the first to be discovered in the globular cluster M15. It is a blue straggler and is located 102\arcsec.8 north and 285\arcsec.6 west of the center of M15 \citep{har96}. Mean magnitudes of SXP1 are = 18$\fm$671 and = 18\fm445. The amplitude of variability of SXP1 is measured to be ΔV0.15\Delta V \approx 0.15. From multiple-frequency analysis based on the Fourier decomposition method, we detect two very closely separated pulsating frequencies: the primary frequency at f1=24.630f_1=24.630 c/d for both BB- and VV-bands, and the secondary frequency at f2=24.338f_2=24.338 c/d for the BB-band and 24.343 c/d for the VV-band. This star is the second among known SX Phe stars found to pulsate with very closely separated frequencies (f2/f10.95f_2/f_1\ge0.95). These frequencies may be explained by excitation of nonradial modes; however, we have an incomplete understanding of this phenomenon in the case of SX Phe stars with relatively high amplitudes. The metallicity-period and the variability amplitude-period relations for SXP1 in M15 are found to be consistent with those for SX Phe stars in other globular clusters.Comment: 15 pages with 6 figures, accepted by the Astronomical Journal (scheduled May 2001

    Determination of Vitamin C in Fresh Fruits and Vegetables Using the Dye-titration and Microfluorometric Methods

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    The vitamin C content of19 types of fresh fruits and 24 vegetables was determined by the official AOAC methods of dye-titration and microfluorometry. As expected, values obtained by the latter method, which estimated ascorbic acid plus dehydroascorbic acid (DHAA), were clearly higher than those given by the titration method, which determined only ascorbic acid. There were considerable differences in the values obtained by the two methods, depending on the concentration ofDHAA in the foods. Larger differences were obtained for the vegetables. The mean recovery value obtained by the dye-titration method was significantly higher than that given by the fluorometric method (p <0.01). Reproducibility studies showed that the two methods did not give significantly different variances (p < 0.05). If only ascorbic acid values were required, the titrimetric procedure would give good results, and it may be ca"ied out rapidly using simple laboratory equipment. If a fluorometer was available, total vitamin C values, which would be more useful from the nutritional point of view, could be determined

    The colonization pattern by resistant microorganisms in an adult intensive care unit (ICU)

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    Effect of biochars pyrolyzed in N2 and CO2, and feedstock on microbial community in metal(loid)s contaminated soils

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    Little is known about the effects of applying amendments on soil for immobilizing metal(loid)s on the soil microbial community. Alterations in the microbial community were examined after incubation of treated contaminated soils. One soil was contaminated with Pb and As, a second soil with Cd and Zn. Red pepper stalk (RPS) and biochars produced from RPS in either N2 atmosphere (RPSN) or CO2 atmosphere (RPSC) were applied at a rate of 2.5% to the two soils and incubated for 30 days. Bacterial communities of control and treated soils were characterized by sequencing 16S rRNA genes using the Illumina MiSeq sequencing. In both soils, bacterial richness increased in the amended soils, though somewhat differently between the treatments. Evenness values decreased significantly, and the final overall diversities were reduced. The neutralization of pH, reduced available concentrations of Pb or Cd, and supplementation of available carbon and surface area could be possible factors affecting the community changes. Biochar amendments caused the soil bacterial communities to become more similar than those in the not amended soils. The bacterial community structures at the phylum and genus levels showed that amendment addition might restore the normal bacterial community of soils, and cause soil bacterial communities in contaminated soils to normalize and stabilize

    The age of data-driven proteomics : how machine learning enables novel workflows

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    A lot of energy in the field of proteomics is dedicated to the application of challenging experimental workflows, which include metaproteomics, proteogenomics, data independent acquisition (DIA), non-specific proteolysis, immunopeptidomics, and open modification searches. These workflows are all challenging because of ambiguity in the identification stage; they either expand the search space and thus increase the ambiguity of identifications, or, in the case of DIA, they generate data that is inherently more ambiguous. In this context, machine learning-based predictive models are now generating considerable excitement in the field of proteomics because these predictive models hold great potential to drastically reduce the ambiguity in the identification process of the above-mentioned workflows. Indeed, the field has already produced classical machine learning and deep learning models to predict almost every aspect of a liquid chromatography-mass spectrometry (LC-MS) experiment. Yet despite all the excitement, thorough integration of predictive models in these challenging LC-MS workflows is still limited, and further improvements to the modeling and validation procedures can still be made. In this viewpoint we therefore point out highly promising recent machine learning developments in proteomics, alongside some of the remaining challenges

    A morphological comparison between the central region in AGN and normal galaxies using HST data

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    We study the morphology of the central region of a sample of Active Galactic Nuclei (AGN) and a ``control'' sample of normal galaxies using archival observations of the WFPC2 instrument onboard the Hubble Space Telescope (HST). We use the ellipse fitting technique in order to get a good description of the inner ``smooth'' light distribution of the galaxy. We then divide the observed galaxy image by the artificial image from the fitted ellipses in order to detect morphological signatures in the central region around the nucleus of the galaxy. We perform quantitative comparisons of different subgroups of our sample of galaxies (according to the Hubble type and the nuclear activity of the galaxies) by calculating the average amplitude of the structures that are revealed with the ellipse fitting technique. Our main conclusions are as follows: 1) All AGNs show significant structure in their inner 100 pc and 1 kpc regions whose amplitude is similar in all of them, independent of the Hubble type of the host galaxy. 2) When considering early-type galaxies, non-AGN galaxies show no structure at all, contrary to what we find for AGN. 3) When considering late-type galaxies, both AGN and non-AGN galaxies show significant structure in their central region. Our results are consistent with the hypothesis that all early-type galaxies host a supermassive black hole, but only those that have enough material in the central regions to fuel it show an active nucleus. The situation is more complicated in late-type galaxies. Either not all of them host a central black hole, or, in some of them, the material inside the innermost 100 pc region is not transported to the scales of the central engine for some reason, or the large amount of gas and dust hides the active nucleus from our sight.Comment: Accepted for publication in A&A. A gziped ps file with high resolution figures is available at http://armonia.physics.uoc.gr/~xilouris/publications/pub.htm
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