700 research outputs found

    Exponential stability of the wave equation with memory and time delay

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    We study the asymptotic behaviour of the wave equation with viscoelastic damping in presence of a time-delayed damping. We prove exponential stability if the amplitude of the time delay term is small enough

    Conjugate times and regularity of the minimum time function with differential inclusions

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    This paper studies the regularity of the minimum time function, T()T(\cdot), for a control system with a general closed target, taking the state equation in the form of a differential inclusion. Our first result is a sensitivity relation which guarantees the propagation of the proximal subdifferential of TT along any optimal trajectory. Then, we obtain the local C2C^2 regularity of the minimum time function along optimal trajectories by using such a relation to exclude the presence of conjugate times

    Nightmare disorder and REM sleep behavior disorder in inflammatory arthritis: Possibility beyond neurodegeneration.

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    OBJECTIVES:To investigate the prevalence of REM sleep behavior disorder (RBD) in patients with inflammatory arthritis (IA) to ascertain if RBD could be an internal red flag signaling a fluctuating state of inflammation based on the theory of "protoconsciousness". MATERIALS & METHODS:One hundred and three patients with a confirmed diagnosis of IA were consecutively recruited. The patients underwent general (IA activity, functional status, laboratory tests) and neurological evaluations. A neurologist investigated RBD and REM sleep parasomnias in a semi-structured interview. Sleep quality was assessed with the Pittsburgh Sleep Quality Index, while the risk of obstructive sleep apnea syndrome (OSAS) was evaluated with the Berlin questionnaire. Beck Depression Inventory II and State-Trait Anxiety Inventory investigated depression and anxiety. RESULTS:Patients had a mean age of 53.7 ± 14.6 years, 65% were women; 57.3% were in a clinically active phase of IA. Two women fulfilled ICSD-3 criteria for RBD appearing 11 years after and 20 years before IA onset respectively. 31 patients scored positive for nightmare disorder (ND), 8 for recurrent isolated sleep paralysis. 65 (63.1%) patients reported poor sleep quality and 25 (24.3%) resulted at high risk for OSAS. 32 (31.0%) patients scored positively for depression or anxiety. CONCLUSIONS:The prevalence of RBD in patients with IA did not differ from that in the general population, whereas ND presented a 2-fold increased prevalence. Whether RBD can be considered a red flag signaling an internal danger remains an open question, while ND may be a new player in this intriguing relation

    Advanced Dissection Lab for Neuroanatomy Training

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    tert-Butyl 2-methyl-2-(4-nitro­benzo­yl)propanoate

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    The title compound, C15H19NO5, is bent with a dihedral angle of 61.8 (2)° between the mean planes of the benzene ring and a group encompassing the ester functionality (O=C—O—C). The dihedral angle of 0.8 (2)° between the mean planes of the nitro group and the benzene ring indicates near coplanarity. In the crystal, each mol­ecule is linked to four adjacent mol­ecules by weak C—H⋯O hydrogen-bonding inter­actions. Both benzene H atoms ortho to the ketone O atom form C—H⋯O hydrogen bonds with the keto O atoms of two neighboring mol­ecules (of the keto and ester groups, respectively), and the two other inter­actions involve the H atoms from a methyl group of the dimethyl residue, displaying C—H⋯O inter­actions with the O atoms of the nitro groups. These four inter­actions for each mol­ecule lead to the formation of two-dimensional sheets with a hydro­philic inter­ior, held together by weak hydrogen-bonded inter­actions, and a hydro­phobic exterior composed of protruding methyl groups which interst­ack with the methyl groups in adjacent sheets

    A novel comprehensive clinical stratification model to refine prognosis of glioblastoma patients undergoing surgical resection

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    Despite recent discoveries in genetics and molecular fields, glioblastoma (GBM) prognosis still remains unfavorable with less than 10% of patients alive 5 years after diagnosis. Numerous studies have focused on the research of biological biomarkers to stratify GBM patients. We addressed this issue in our study by using clinical/molecular and image data, which is generally available to Neurosurgical Departments in order to create a prognostic score that can be useful to stratify GBM patients undergoing surgical resection. By using the random forest approach [CART analysis (classification and regression tree)] on Survival time data of 465 cases, we developed a new prediction score resulting in 10 groups based on extent of resection (EOR), age, tumor volumetric features, intraoperative protocols and tumor molecular classes. The resulting tree was trimmed according to similarities in the relative hazard ratios amongst groups, giving rise to a 5-group classification tree. These 5 groups were different in terms of overall survival (OS) (p < 0.000). The score performance in predicting death was defined by a Harrell\u2019s c-index of 0.79 (95% confidence interval [0.76\u20130.81]). The proposed score could be useful in a clinical setting to refine the prognosis of GBM patients after surgery and prior to postoperative treatment

    A unified parameter identification method for nonlinear time-delay systems

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    This paper deals with the problem of identifying unknown time-delays and model parameters in a general nonlinear time-delay system. We propose a unified computational approach that involves solving a dynamic optimization problem, whose cost function measures the discrepancy between predicted and observed system output, to determine optimal values for the unknown quantities. Our main contribution is to show that the partial derivatives of this cost function can be computed by solving a set of auxiliary time-delay systems. On this basis, the parameter identification problem can be solved using existing gradient-based optimization techniques. We conclude the paper with two numerical simulations

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

    Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

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    Results of a search for H → τ τ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb−1 and 20.3 fb−1 at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV respectively. All combinations of leptonic (τ → `νν¯ with ` = e, µ) and hadronic (τ → hadrons ν) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalised to the Standard Model expectation, of µ = 1.43 +0.43 −0.37 is consistent with the predicted Yukawa coupling strength in the Standard Model
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