6,652 research outputs found

    A k-omega-multivariate beta PDF for supersonic combustion

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    In an attempt to study the interaction between combustion and turbulence in supersonic flows, an assumed PDF has been employed. This makes it possible to calculate the time average of the chemical source terms that appear in the species conservation equations. In order to determine the averages indicated in an equation, two transport equations, one for the temperature (enthalpy) variance and one for Q, are required. Model equations are formulated for such quantities. The turbulent time scale controls the evolution. An algebraic model similar to that used by Eklund et al was used in an attempt to predict the recent measurements of Cheng et al. Predictions were satisfactory before ignition but were less satisfactory after ignition. One of the reasons for this behavior is the inadequacy of the algebraic turbulence model employed. Because of this, the objective of this work is to develop a k-omega model to remedy the situation

    WATER RESOURCES IN THE WIDER AREA OF THE APOSELEMIS BASIN, CRETE ISLAND, GREECE

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    Η γνώση του υδρολογικού ισοζυγίου μιας λεκάνης αποτελεί απαραίτητη προϋπόθεση για να εκτιμηθεί η ασφαλής απόδοση των υδροφόρων συστημάτων ώστε να εξασφαλι­ σθεί η ορθολογική και βιώσιμη διαχείριση τους. Προκειμένου να αντιμετωπιστεί η διαταραχή της ισορροπίας του υδατικού ισοζυγίου στην υδρογεωλογική λεκάνη του Αποσελέμη αλλά και στον ευρύτερο χώρο του όρους Δίκτη είναι απαραίτητη η εκτίμη­ ση του υδατικού ισοζυγίου των επιμέρους λεκανών απορροής δηλαδή της λεκάνης του Αποσελέμη, των οροπεδίων Λασιθίου και Καθαρού καθώς και της υπόλοιπης επιφάνειας απορροής του όρους Δίκτη. Προς τούτο χρησιμοποιήθηκαν οι καταγραφές της απορροής του Αποσελέμη στη θέση Ποταμιές και οι μετρήσεις βροχής σε επτά βροχομετρικούς σταθμούς εντός ή πλησίον της λεκάνης απορροής του Αποσελέμη κατά την περίοδο 1967-2003. Τα όρια των περιοχών και οι μορφολογικές παράμετροι καθορί­ στηκαν με τη χρήση GIS, με βάση το ψηφιακό μοντέλο ανάγλυφου (DEM). Η πραγμα­ τική εξατμισοδιαπνοή σε όλη τη περιοχή υπολογίστηκε με τη μέθοδο ThornthwaiteMather. Διαπιστώθηκε υψηλός βαθμός συσχέτισης της απορροής του Αποσελέμη με τη βροχόπτωση στην ευρύτερη περιοχή πέρα από τα συμβατικά όρια της λεκάνης απορ­ ροής του. Σημαντικό ποσοστό της ετήσιας βροχόπτωσης και απορροής στην περιοχή τροφοδοτεί τόσο τα καρστικά υδροφόρα συστήματα κατάντη όσο και την απορροή του Αποσελέμη. Οι καρστικοί υδροφορίες εκφορτίζονται μερικώς από μεγάλες παράκτιες και υποθαλάσσιες υφάλμυρες πηγές, καθώς και από μικρότερες πηγές γλυκού νερού στην ενδοχώρα. Επιβεβαιώθηκε τέλος με ιχνηθετήσεις που εκτέλεσε το ΙΓΜΕ η υ­ δραυλική επικοινωνία του οροπεδίου Λασιθίου και των κατάντη υδροφορέων.The estimation of hydrologie balance is useful in order to assess the safe yield of the aquifer systems and therefore to establish their rational exploitation and sustainable management. Over-abstractions of groundwater in Aposelemis basin resulted in a severe disequilibrium of its water balance. In order to overcome this disequilibrium we studied the hydrological balance in the wider area ofDikti mountain which comprises the drainage basins of Aposelemis river, ofLasithi and Katharo plateaus and of the rest of the drainage area of Dikti. The data used are the monthly values of Aposelemis runoff in the gauge station at Potamies and rainfall data for the period 1967-2003 from seven stations located within or in the close vicinity of the drainage basin of Aposelemis. Using ArcView GIS, the hydrological basin of Aposelemis river and the drainage area ofDikti were delineated, based on the digital elevation model (DEM). The actual évapotranspiration was estimated by the Thornthwaite method. A high inter-relationship exists between the flow of the Aposelemis river and rainfall outside the conventional boundaries of the Aposelemis basin. A significant portion of the annual rainfall, in that wider area is not only recharging the karst systems downstream but also contributing to the flow of Aposelemis river. Karst aquifer systems are partially drained by large coastal and submarine brackish springs and by inland freshwater springs. Finally, tracer studies carried out by IGME confirmed the hydraulic connection between Lasithiplateau and downstream aquifer systems

    Possible scenarios for soft and semi-hard components structure in central hadron-hadron collisions in the TeV region

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    Possible scenarios in hh collisions in the TeV regions are discussed in full phase space. It is shown that at such high energies one should expect strong KNO scaling violation and a ln(s) increase of the average charged multiplicity of the semi-hard component, resulting in a huge mini-jet production.Comment: 20 pages, 9 PS figures included, LaTeX2e with AMSmath, epsfi

    Identification of signaling pathways related to drug efficacy in hepatocellular carcinoma via integration of phosphoproteomic, genomic and clinical data

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    Hepatocellular Carcinoma (HCC) is one of the leading causes of death worldwide, with only a handful of treatments effective in unresectable HCC. Most of the clinical trials for HCC using new generation interventions (drug-targeted therapies) have poor efficacy whereas just a few of them show some promising clinical outcomes [1]. This is amongst the first studies where the mode of action of some of the compounds extensively used in clinical trials is interrogated on the phosphoproteomic level, in an attempt to build predictive models for clinical efficacy. Signaling data are combined with previously published gene expression and clinical data within a consistent framework that identifies drug effects on the phosphoproteomic level and translates them to the gene expression level. The interrogated drugs are then correlated with genes differentially expressed in normal versus tumor tissue, and genes predictive of patient survival. Although the number of clinical trial results considered is small, our approach shows potential for discerning signaling activities that may help predict drug efficacy for HCC.National Institutes of Health (U.S.) (Grant U54-CA119267)National Institutes of Health (U.S.) (Grant R01-CA96504

    Measuring the Charged Particle Multiplicity with ALICE

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    The charged particle multiplicity distribution is one of the first measurements that ALICE will be able to perform. The knowledge of this basic property at a new energy is needed to configure Monte Carlo generators correctly with the aim of understanding the background of other, especially rare, processes including new physics. It allows to study the scaling behaviour and to verify model predictions. The unfolding of the measurement is a non-trivial task due to the finite precision and acceptance of the detector. Solutions are based on chi2 minimization or iteratively using Bayes' theorem. Both approaches to unfold the spectrum are presented. Furthermore, the capabilities of the SPD fast OR trigger are shown that enable physics at very high multiplicities.Comment: Proceedings of poster presentation at Quark Matter 2008, 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions in Jaipur, India; to be published in Indian Journal of Physics; 4 pages, 4 figure

    Percolation approach to quark gluon plasma in high energy pp collisions

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    We apply continuum percolation to proton-proton collisions and look for the possible threshold to phase transition from confined nuclear matter to quark gluon plasma. Making the assumption that J/Psi suppression is a good signal to the transition, we discuss this phenomenon for pp collisions, in the framework of a dual model with strings.Comment: 8 pages, 3 figure

    Fine specificity of antibodies against AQP4: Epitope mapping reveals intracellular epitopes

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    The autoantibody to aquaporin-4 (AQP4) is a marker and a pathogenetic factor in Neuromyelitis Optica (NMO) (Devic’s syndrome). Our aim was to identify B-cell antigenic linear epitopes of the AQP4 protein and investigate similarities with other molecules. To this end, we screened sera from 21 patients positive for anti-AQP4 antibodies (study group), from 23 SLE and 23 pSS patients without neurologic involvement (disease controls) and from 28 healthy individuals (normal controls). Eleven peptides, spanning the entire intracellular and extracellular domains of the AQP4 molecule, were synthesized, and all sera were screened for anti-peptide antibodies by ELISA. Specificity was evaluated by homologous inhibition assays. NMO positive sera exhibited reactivity against 3 different peptides spanning the sequences aa1e22 (AQPpep1) (42.9% of patients), aa88e113 (AQPpep4) (33%) and aa252e275 (AQPpep8) (23.8%). All epitopes were localized in the intracellular domains of AQP4. Homologous inhibition rates were ranging from 71.1% to 84.3%. A 73% sequence homology was observed between AQPpep80 aa257e271, a 15-mer peptide part of the AQPpep8 aa252e275, and the aa219e233 domain of the Tax1-HTLV-1 binding protein (TAX1BP1), a host protein associated with replication of the Human T-Lymphotropic Virus 1 (HTLV-1). Antibodies against the AQP4 and the TAX1BP1 15-mer peptides were detected in 26.3% (N ¼ 5) and 31.6% (N ¼ 6) of NMO positive sera (rs ¼ 0.81, P < 0.0001). Healthy controls did not react with these peptides, while homologous and cross-inhibition assays confirmed binding specificity. This first epitope mapping for AQP4 reveals that a significant proportion of anti-AQP4 antibodies target linear epitopes localized in the intracellular domains of the channel. One of the epitopes displays high similarity with a portion of TAX1BP1 protein

    Performances of Anode-resistive Micromegas for HL-LHC

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    Micromegas technology is a promising candidate to replace Atlas forward muon chambers -tracking and trigger- for future HL-LHC upgrade of the experiment. The increase on background and pile-up event probability requires detector performances which are currently under studies in intensive RD activities. We studied performances of four different resistive Micromegas detectors with different read-out strip pitches. These chambers were tested using \sim120 GeV momentum pions, at H6 CERN-SPS beam line in autumn 2010. For a strip pitch 500 micrometers we measure a resolution of \sim90 micrometers and a efficiency of ~98%. The track angle effect on the efficiency was also studied. Our results show that resistive techniques induce no degradation on the efficiency or resolution, with respect to the standard Micromegas. In some configuration the resistive coating is able to reduce the discharge currents at least by a factor of 100.Micromegas technology is a promising candidate to replace Atlas forward muon chambers -tracking and trigger- for future HL-LHC upgrade of the experiment. The increase on background and pile-up event probability requires detector performances which are currently under studies in intensive RD activities. We studied performances of four different resistive Micromegas detectors with different read-out strip pitches. These chambers were tested using \sim120 GeV momentum pions, at H6 CERN-SPS beam line in autumn 2010. For a strip pitch 500 micrometers we measure a resolution of \sim90 micrometers and a efficiency of \sim98%. The track angle effect on the efficiency was also studied. Our results show that resistive techniques induce no degradation on the efficiency or resolution, with respect to the standard Micromegas. In some configuration the resistive coating is able to reduce the discharge currents at least by a factor of 100.Comment: "Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 3 pages, 6 figures.
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