619 research outputs found

    Simultaneous cross section measurements of top quark-antiquark pair production with additional heavy flavor jets at the CMS experiment

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    This thesis presents a simultaneous cross section measurement of top quark-antiquark pair (ttˉ\text{t}\bar{\text{t}}) production in association with b jets, c jets, a Higgs boson, or a Z boson in the H/Zbbˉ\text{H/Z}\to \text{b}\bar{\text{b}} decay mode with exactly two charged leptons (e,μ\mu), targeting the dilepton ttˉ\text{t}\bar{\text{t}} decay channel. The measurement is performed at the CMS experiment at the CERN LHC in proton-proton collisions at a center-of-mass energy of 13TeV13\,\text{TeV} and the analyzed data corresponds to an integrated luminosity of approximately 60fb160\,\text{fb}^{-1}. Collision events are modeled as a mathematical graph structure and processed using graph transformer neural network architectures based on multi-head attention mechanisms to perform multi-class classification. The measured cross sections are parameterized as signal strength parameters relative to the cross sections predicted by the SM. Four signal strength parameters are simultaneously extracted in a maximum likelihood fit to data and result to μttˉBobs=0.980.25+0.34\mu_{\text{t}\bar{\text{t}}\text{B}}^{\text{obs}} = 0.98^{+0.34}_{-0.25}, μttˉCobs=0.740.41+0.41\mu_{\text{t}\bar{\text{t}}\text{C}}^{\text{obs}} = 0.74^{+0.41}_{-0.41}, μttˉHobs=0.890.93+0.95\mu_{\text{t}\bar{\text{t}}\text{H}}^{\text{obs}} = 0.89^{+0.95}_{-0.93}, and μttˉZobs=1.281.06+1.15\mu_{\text{t}\bar{\text{t}}\text{Z}}^{\text{obs}} = 1.28^{+1.15}_{-1.06} , corresponding to an observed (expected) significance of 15σ15\sigma (16σ16\sigma) for ttˉB\text{t}\bar{\text{t}}\text{B}, 1.8σ1.8\sigma (2.9σ2.9\sigma) for ttˉC\text{t}\bar{\text{t}}\text{C}, 1.0σ1.0\sigma (1.1σ1.1\sigma) for ttˉH\text{t}\bar{\text{t}}\text{H}, and 1.2σ1.2\sigma (1.0σ1.0\sigma) for ttˉZ\text{t}\bar{\text{t}}\text{Z} compared to the SM prediction without these processes. The results reveal a good agreement with the SM expectation for the signal strength of one within the 68% confidence interval

    Typhoon damage on a shallow mesophotic reef in Okinawa, Japan

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    Little is known about effects of large storm systems on mesophotic reefs. This study reports on how Typhoon 17 (Jelawat) affected Ryugu Reef on Okinawa-jima, Japan in September 2012. Benthic communities were surveyed before and after the typhoon using line intercept transect method. Comparison of the benthic assemblages showed highly significant differences in coral coverage at depths of 25–32 m before and after Typhoon 17. A large deep stand of Pachyseris foliosa was apparently less resistant to the storm than the shallower high diversity area of this reef. Contradictory to common perception, this research shows that large foliose corals at deeper depths are just as susceptible to typhoon damage as shallower branching corals. However, descriptive functional group analyses resulted in only minor changes after the disturbance, suggesting the high likelihood of recovery and the high resilience capacity of this mesophotic reef

    Heavy flavor jet tagging algorithm developments at CMS for HL-LHC

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    The rich physics program at the high luminosity LHC (HL-LHC) requires all final state particles to be reconstructed with good accuracy. However, it also poses formidable challenge of dealing with very high pileup. Different identification algorithms need to be upgraded along with the detectors to improve the overall event reconstruction in such a hostile collision environment. The new timing device in the proposed CMS detector at the HL-LHC allows for the construction of timing observables at the track-level as well as at the jet-level. This information when given as inputs to the deep neural networks, have a potential to improve the existing algorithms used for heavy flavor (HF) jet tagging. In this paper, the latest developments on the studies for HF jet tagging performance at the HL-LHC are presented

    "If HTTPS Were Secure, I Wouldn't Need 2FA" - End User and Administrator Mental Models of HTTPS

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    HTTPS is one of the most important protocols used to secure communication and is, fortunately, becoming more pervasive. However, especially the long tail of websites is still not sufficiently secured. HTTPS involves different types of users, e.g., end users who are forced to make security decisions when faced with warnings or administrators who are required to deal with cryptographic fundamentals and complex decisions concerning compatibility. In this work, we present the first qualitative study of both end user and administrator mental models of HTTPS. We interviewed 18 end users and 12 administrators; our findings reveal misconceptions about security benefits and threat models from both groups. We identify protocol components that interfere with secure configurations and usage behavior and reveal differences between administrator and end user mental models. Our results suggest that end user mental models are more conceptual while administrator models are more protocol-based. We also found that end users often confuse encryption with authentication, significantly underestimate the security benefits of HTTPS. They also ignore and distrust security indicators while administrators often do not understand the interplay of functional protocol components. Based on the different mental models, we discuss implications and provide actionable recommendations for future designs of user interfaces and protocols

    Inhibiting Androgen Receptor Splice Variants With Cysteine-Selective Irreversible Covalent Inhibitors To Treat Prostate Cancer

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    Androgen receptor (AR) and its splice variants (AR-SVs) promote prostate cancer (PCa) growth by orchestrating transcriptional reprogramming. Mechanisms by which the low complexity and intrinsically disordered primary transactivation domain (AF-1) of AR and AR-SVs regulate transcriptional programming in PCa remains poorly defined. Using omics, live and fixed fluorescent microscopy of cells, and purified AF-1 and AR-V7 recombinant proteins we show here that AF-1 and the AR-V7 splice variant form molecular condensates by liquid-liquid phase separation (LLPS) that exhibit disorder characteristics such as rapid intracellular mobility, coactivator interaction, and euchromatin induction. The LLPS and other disorder characteristics were reversed by a class of small-molecule-selective AR-irreversible covalent antagonists (SARICA) represented herein by UT-143 that covalently and selectively bind to C406 and C327 in the AF-1 region. Interfering with LLPS formation with UT-143 or mutagenesis resulted in chromatin condensation and dissociation of AR-V7 interactome, all culminating in a transcriptionally incompetent complex. Biochemical studies suggest that C327 and C406 in the AF-1 region are critical for condensate formation, AR-V7 function, and UT-143\u27s irreversible AR inhibition. Therapeutically, UT-143 possesses drug-like pharmacokinetics and metabolism properties and inhibits PCa cell proliferation and tumor growth. Our work provides critical information suggesting that clinically important AR-V7 forms transcriptionally competent molecular condensates and covalently engaging C327 and C406 in AF-1, dissolves the condensates, and inhibits its function. The work also identifies a library of AF-1-binding AR and AR-SV-selective covalent inhibitors for the treatment of PCa

    Vertigo's Musical Gaze: Neo-Riemannian Symmetries and Spirals

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    Laura Mulvey coined the term ‘male gaze’ (1975), using Lacanian theory as a ‘political weapon’ against the standard mode of viewing in which the viewing subject turns onscreen women into fantasy objects. While politically laudable, her article misconstrues Lacan's concept of ‘the gaze’, the power of which emanates from the object itself. We might better serve Lacanian theory by inverting Mulvey's reading of Alfred Hitchcock's Vertigo to suggest that Scottie (James Stewart) is himself objectified by the mystique of the ‘object’ he watches and follows: Madeleine (Kim Novak). The screen's gaze reduces spectators to objects too. From this perspective, rather than watching the film, the film can be said to be watching us. This extends to Bernard Herrmann's soundtrack, famously influenced by the yearning of Wagner's Tristan und Isolde . Developing David Schwarz's (2006) musical gaze (in which repeated pedal points of Schubert songs gaze at us), I analyse Vertigo ’s frequent emphasis on the pitch class D. A pedal D is often repeated in alluring yet sinister bare octaves as Scottie follows Madeleine. But at key moments in the film, the pitch becomes a sophisticated tool that captivates us in unique ways. Around this central pitch third‐relationships circle. These resonate with neo‐Riemannian theory, particularly in their hexatonic ‘poles’, which Cohn shows to be agents of the Freudian ‘uncanny’ (2004) and which here also serve as an alternative gaze to the reiterated D. Other pitch constellations, in symmetries or spirals, form similar obsessional musical ‘gazes’ that, using Lacanian theory, prompt the question about whether we are listening to the music or the music is listening to us

    Development of Resistance towards Artesunate in MDA-MB-231 Human Breast Cancer Cells

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    Breast cancer is the most common cancer and the second leading cause of cancer death in industrialized countries. Systemic treatment of breast cancer is effective at the beginning of therapy. However, after a variable period of time, progression occurs due to therapy resistance. Artesunate, clinically used as anti-malarial agent, has recently revealed remarkable anti-tumor activity offering a role as novel candidate for cancer chemotherapy. We analyzed the anti-tumor effects of artesunate in metastasizing breast carcinoma in vitro and in vivo. Unlike as expected, artesunate induced resistance in highly metastatic human breast cancer cells MDA-MB-231. Likewise acquired resistance led to abolishment of apoptosis and cytotoxicity in pre-treated MDA-MB-231 cells. In contrast, artesunate was more cytotoxic towards the less tumorigenic MDA-MB-468 cells without showing resistance. Unraveling the underlying molecular mechanisms, we found that resistance was induced due to activation of the tumor progression related transcription factors NFκB and AP-1. Thereby transcription, expression and activity of the matrix-degrading enzyme MMP-1, whose function is correlated with increased invasion and metastasis, was up-regulated upon acquisition of resistance. Additionally, activation of the apoptosis-related factor NFκB lead to increased expression of ant-apoptotic bcl2 and reduced expression of pro-apoptotic bax. Application of artesunate in vivo in a model of xenografted breast cancer showed, that tumors growth was not efficiently abolished as compared to the control drug doxorubicin. Taken together our in vitro and in vivo results correlate well showing for the first time that artesunate induces resistance in highly metastatic breast tumors

    Observation of γγ → ττ in proton-proton collisions and limits on the anomalous electromagnetic moments of the τ lepton

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    The production of a pair of τ leptons via photon–photon fusion, γγ → ττ, is observed for the f irst time in proton–proton collisions, with a significance of 5.3 standard deviations. This observation is based on a data set recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 138 fb−1. Events with a pair of τ leptons produced via photon–photon fusion are selected by requiring them to be back-to-back in the azimuthal direction and to have a minimum number of charged hadrons associated with their production vertex. The τ leptons are reconstructed in their leptonic and hadronic decay modes. The measured fiducial cross section of γγ → ττ is σfid obs = 12.4+3.8 −3.1 fb. Constraints are set on the contributions to the anomalous magnetic moment (aτ) and electric dipole moments (dτ) of the τ lepton originating from potential effects of new physics on the γττ vertex: aτ = 0.0009+0.0032 −0.0031 and |dτ| < 2.9×10−17ecm (95% confidence level), consistent with the standard model
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