450 research outputs found

    Modeling the non-Markovian, non-stationary scaling dynamics of financial markets

    Full text link
    A central problem of Quantitative Finance is that of formulating a probabilistic model of the time evolution of asset prices allowing reliable predictions on their future volatility. As in several natural phenomena, the predictions of such a model must be compared with the data of a single process realization in our records. In order to give statistical significance to such a comparison, assumptions of stationarity for some quantities extracted from the single historical time series, like the distribution of the returns over a given time interval, cannot be avoided. Such assumptions entail the risk of masking or misrepresenting non-stationarities of the underlying process, and of giving an incorrect account of its correlations. Here we overcome this difficulty by showing that five years of daily Euro/US-Dollar trading records in the about three hours following the New York market opening, provide a rich enough ensemble of histories. The statistics of this ensemble allows to propose and test an adequate model of the stochastic process driving the exchange rate. This turns out to be a non-Markovian, self-similar process with non-stationary returns. The empirical ensemble correlators are in agreement with the predictions of this model, which is constructed on the basis of the time-inhomogeneous, anomalous scaling obeyed by the return distribution.Comment: Throughout revision. 15 pages, 6 figures. Presented by A.L. Stella in a Talk at the "Econophysics - Kolkata V'' International Workshop, March 2010, Saha Institute of Nuclear Physics, Kolkata, Indi

    Hyaluronan fragments induce IFNβ via a novel TLR4-TRIF-TBK1-IRF3- dependent pathway

    Get PDF
    Background: The extracellular matrix plays a critical role in insuring tissue integrity and water homeostasis. However, breakdown products of the extracellular matrix have emerged as endogenous danger signals, designed to rapidly activate the immune system against a potential pathogen breach. Type I interferons play a critical role in the immune response against viral infections. In the lungs, hylauronan (HA) exists as a high molecular weight, biologically inert extracellular matrix component that is critical for maintaining lung function. When lung tissue is injured, HA is broken down into lower molecular weight fragments that alert the immune system to the breach in tissue integrity by activating innate immune responses. HA fragments are known to induce inflammatory gene expression via TLR-MyD88-dependent pathways. Methods. Primary peritoneal macrophages from C57BL/6 wild type, TLR4 null, TLR3 null, MyD88 null, and TRIF null mice as well as alveolar and peritoneal macrophage cell lines were stimulated with HA fragments and cytokine production was assessed by rt-PCR and ELISA. Western blot analysis for IRF3 was preformed on cell lysates from macrophages stimulate with HA fragments. Results: We demonstrate for the first time that IFNβ is induced in murine macrophages by HA fragments. We also show that HA fragments induce IFNβ using a novel pathway independent of MyD88 but dependent on TLR4 via TRIF and IRF-3. Conclusions: Overall our findings reveal a novel signaling pathway by which hyaluronan can modulate inflammation and demonstrate the ability of hyaluronan fragments to induce the expression of type I interferons in response to tissue injury even in the absence of viral infection. This is independent of the pathway of the TLR2-MyD88 used by these matrix fragments to induce inflammatory chemokines. Thus, LMW HA may be modifying the inflammatory milieu simultaneously via several pathways

    Comprehensive molecular characterization of urachal adenocarcinoma reveals commonalities with colorectal cancer, including a hypermutable phenotype

    Get PDF
    Purpose Urachal adenocarcinoma is a rare type of primary bladder adenocarcinoma that comprises less than 1% of all bladder cancers. The low incidence of urachal adenocarcinomas does not allow for an evidence-based approach to therapy. Transcriptome profiling of urachal adenocarcinomas has not been previously reported.Wehypothesized that an in-depth molecular understanding of urachal adenocarcinoma would uncover rational therapeutic strategies. Patients and Methods We performed targeted exon sequencing and global transcriptome profiling of 12 urachal tumors to generate a comprehensive molecular portrait of urachal adenocarcinoma. A single patient with an MSH6 mutation was treated with the anti-programmed death-ligand 1 antibody, atezolizumab. Results Urachal adenocarcinoma closely resembles colorectal cancer at the level of RNA expression, which extends previous observations that urachal tumors harbor genomic alterations that are found in colorectal adenocarcinoma. A subset of tumors was found to have alterations in genes that are associated with microsatellite instability (MSH2 and MSH6) and hypermutation (POLE).Apatient with anMSH6mutation was treated withimmunecheckpoint blockade, which resulted in stable disease. Conclusion Because clinical trials are next to impossible for patients with rare tumors, precision oncology may be an important adjunct for treatment decisions. Our findings demonstrate that urachal adenocarcinomas molecularly resemble colorectal adenocarcinomas at the level ofRNA expression, are the first report, to our knowledge, of MSH2andMSH6mutations in this disease, and support the consideration of immune checkpoint blockade as a rational therapeutic treatment of this exceedingly rare tumor

    Appraising empirical applications of Structuration Theory in management and organization studies

    Get PDF
    There is an increasing interest in the application of Structuration Theory in the fields of management and organization studies. Based upon a thorough literature review, we have come up with a data-set to assess how Structuration Theory has been used in empirical research. We use three key concepts of this theory (duality of structure, knowledgeability, and time-space) as sensitizing concepts for our analysis. We conclude that the greatest potential of Structuration Theory for management and organization studies is to view it as a process theory that offers a distinct building block for explaining intra and interorganizational change, as exemplified through concepts such as routine, script, genre, practice, and discourse

    Community advisory boards guiding engaged research efforts within a clinical translational sciences award: Key contextual factors explored

    Get PDF
    Background: Engaging stakeholders in research carries the promise of enhancing the research relevance, transparency, and speed of getting findings into practice. By describing the context and functional aspects of stakeholder groups, like those working as community advisory boards (CABs), others can learn from these experiences and operationalize their own CABs. Our objective is to describe our experiences with diverse CABs affiliated with our community engagement group within our institution’s Clinical Translational Sciences Award (CTSA). We identify key contextual elements that are important to administering CABs. Methods: A group of investigators, staff, and community members engaged in a 6-month collaboration to describe their experiences of working with six research CABs. We identified the key contextual domains that illustrate how CABS are developed and sustained. Two lead authors, with experience with CABs and identifying contextual domains in other work, led a team of 13 through the process. Additionally, we devised a list of key tips to consider when devising CABs. Results: The final domains include (1) aligned missions among stakeholders (2) resources/support, (3) defined operational processes/shared power, (4) well-described member roles, and (5) understanding and mitigating challenges. The tips are a set of actions that support the domains. Conclusions: Identifying key contextual domains was relatively easy, despite differences in the respective CAB’s condition of focus, overall mission, or patient demographics represented. By contextualizing these five domains, other research and community partners can take an informed approach to move forward with CAB planning and engaged research

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

    Get PDF
    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

    Get PDF
    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

    Get PDF
    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

    Get PDF
    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

    Get PDF
    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters
    corecore