72 research outputs found

    Gaussian limits for subcritical chaos

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    peer reviewedWe present a simple criterion, only based on second moment assumptions, for the convergence of polynomial or Wiener chaos to a Gaussian limit. We exploit this criterion to obtain new Gaussian asymptotics for the partition functions of two-dimensional directed polymers in the sub-critical regime, including a singular product between the partition function and the disorder. These results can also be applied to the KPZ and Stochastic Heat Equation. As a tool of independent interest, we derive an explicit chaos expansion which sharply approximates the logarithm of the partition function

    Quasi-critical fluctuations for 2d directed polymers

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    We study the 2d directed polymer in random environment in a novel *quasi-critical regime*, which interpolates between the much studied sub-critical and critical regimes. We prove Edwards-Wilkinson fluctuations throughout the quasi-critical regime, showing that the diffusively rescaled partition functions are asymptotically Gaussian, under a rescaling which diverges arbitrarily slowly as criticality is approached. A key challenge is the lack of hypercontractivity, which we overcome deriving new sharp moment estimates

    Random Evolution Equations: Well-Posedness, Asymptotics, and Applications to Graphs

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    peer reviewedWe study diffusion-type equations supported on structures that are randomly varying in time. After settling the issue of well-posedness, we focus on the asymptotic behavior of solutions: our main result gives sufficient conditions for pathwise convergence in norm of the (random) propagator towards a (deterministic) steady state. We apply our findings in two environments with randomly evolving features: ensembles of difference operators on combinatorial graphs, or else of differential operators on metric graphs

    The Comparative Exploration of the Ice Giant Planets with Twin Spacecraft: Unveiling the History of our Solar System

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    In the course of the selection of the scientific themes for the second and third L-class missions of the Cosmic Vision 2015-2025 program of the European Space Agency, the exploration of the ice giant planets Uranus and Neptune was defined "a timely milestone, fully appropriate for an L class mission". Among the proposed scientific themes, we presented the scientific case of exploring both planets and their satellites in the framework of a single L-class mission and proposed a mission scenario that could allow to achieve this result. In this work we present an updated and more complete discussion of the scientific rationale and of the mission concept for a comparative exploration of the ice giant planets Uranus and Neptune and of their satellite systems with twin spacecraft. The first goal of comparatively studying these two similar yet extremely different systems is to shed new light on the ancient past of the Solar System and on the processes that shaped its formation and evolution. This, in turn, would reveal whether the Solar System and the very diverse extrasolar systems discovered so far all share a common origin or if different environments and mechanisms were responsible for their formation. A space mission to the ice giants would also open up the possibility to use Uranus and Neptune as templates in the study of one of the most abundant type of extrasolar planets in the galaxy. Finally, such a mission would allow a detailed study of the interplanetary and gravitational environments at a range of distances from the Sun poorly covered by direct exploration, improving the constraints on the fundamental theories of gravitation and on the behaviour of the solar wind and the interplanetary magnetic field.Comment: 29 pages, 4 figures; accepted for publication on the special issue "The outer Solar System X" of the journal Planetary and Space Science. This article presents an updated and expanded discussion of the white paper "The ODINUS Mission Concept" (arXiv:1402.2472) submitted in response to the ESA call for ideas for the scientific themes of the future L2 and L3 space mission

    Alteration of glyoxalase genes expression in response to testosterone in LNCaP and PC3 human prostate cancer cells.

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    Glyoxalase system, a ubiquitous detoxification pathway protecting against cellular damage caused by potent cytotoxic metabolites, is involved in the regulation of cellular growth. Aberrations in the expression of glyoxalase genes in several human cancers have been reported. Recently, we described a possible regulatory effect by estrogens on glyoxalase genes in human breast cancer cell lines. This result, along with those ones regarding changes in glyoxalases activity and expression in other human hormone-regulated cancers, such as prostate cancer, has prompted us to investigate whether also androgens, whose functional role in prostate cancer pathogenesis is well known, could modulate glyoxalases gene expression. Therefore, we treated LNCaP androgen-responsive and PC3 androgen-independent human prostate cancer cell lines with testosterone at the concentrations of 1 nM and 100 nM. After a two days treatment, glyoxalases mRNA levels as well as cell proliferation were evaluated by real-time RT-PCR analysis and [3H]thymidine incorporation, respectively. Results pointed out that testosterone affects the expression of glyoxalase system genes and cell proliferation in a different manner in the two cell lines. The possibility that modulation of glyoxalase genes expression by testosterone is due to glyoxalases-mediated intracellular response mechanisms to the androgen-induced oxidative stress or to the presence of androgen response elements (ARE) in glyoxalase promoters are discussed. Knowledge regarding the regulation of glyoxalases by testosterone may provide insights into the importance of these enzymes in human prostate carcinomas in vivo

    Plasma Cystatin C correlates with plasma NfL levels and predicts disease progression in Parkinson's disease

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    INTRODUCTION: Previous studies reported increased plasma levels of Cystatin C (Cys-C) in Parkinson's disease (PD) and claimed for a possible association with disease severity and progression. The aim of this study was to evaluate plasma Cys-C in PD and healthy controls (HC) and test its association with markers of peripheral inflammation, neurodegeneration and clinical progression in a longitudinal study. METHODS: Plasma Cys-C, high-sensitive C-reactive protein (hsCRP), interleukin 6 (IL-6) and Neurofilament Light Chain (NfL) were assessed at the baseline in 71 consecutive non-demented PD and 69 HC. PD patients underwent an extensive motor and cognitive assessment at baseline and after 2 years of follow-up. The association of Cys-C with disease severity was evaluated in a multilinear model adjusted for the effect of age, sex, disease duration and peripheral inflammation. RESULTS: Cys-C levels appeared to be higher in PD compared to controls and correlated with the plasma neuronal marker NfL (r = 0.204, p = 0.046). In longitudinal analyses, PD patients with higher Cys-C levels exhibited faster motor progression at two years of follow-up independently from the peripheral inflammatory profile. CONCLUSIONS: Cys-C was associated with higher NfL levels and a remarkably faster motor progression in PD independently from peripheral inflammation. Further studies are needed in order to understand the mechanisms underpinning the association of Cys-C with higher neuronal damage markers in neurodegenerative diseases

    Serum NFL as a predictor of disease progression in dementia with Lewy bodies

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    AbstractBackgroundCSF and plasma neurofilament light chain (NfL) levels have been consistently proposed as reliable markers of neurodegeneration able to discriminate between Parkinson's disease (PD) and atypical parkinsonisms. Increased Serum NfL might predict worse motor and cognitive progression in PD patients at single subject level.Methodplasma NfL was assessed in a longitudinal study including 93 patients with Parkinson's disease and 27 patients with DLB who underwent an extensive motor and cognitive assessment and after 2 years of follow‐up. The study evaluated the correlation between NfL plasma levels and motor, non‐motor symptoms, cognitive and behavioral abnormalities in the two cohorts, as well as benignant/malignant phenotypes and motor/cognitive progression in PD after 2 years of follow‐up.ResultSerum NfL correlated with age and age at onset in the cohort. In DLB, NfL correlated with disease duration, hyposmia and neuropsychiatric symptoms, but not with motor function assessed by UPDRS‐III. We found no significant associations between NfL and disease progression in DLB patients. In PD, higher NfL levels correlated with hyposmia (p=0.01), total UPDRS‐II and UPDRS‐III scores (0.001), gait speed (0.04) and several disability milestones, including mild cognitive impairment (0.001), symptomatic dysautonomia (0.001), loss of independency in activities of daily living (p=0.01) and instrumental daily living (p=0.001). At two years of follow‐up, NfL was the best marker in multivariate regression analyses for both motor and cognitive progression beyond malignant/benignant phenotypes.ConclusionElevated serum NfL levels are associated with fast progression in PD patients and could thus represent target of interventions in specific subpopulation of patients

    Psychological treatments and psychotherapies in the neurorehabilitation of pain. Evidences and recommendations from the italian consensus conference on pain in neurorehabilitation

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    BACKGROUND: It is increasingly recognized that treating pain is crucial for effective care within neurological rehabilitation in the setting of the neurological rehabilitation. The Italian Consensus Conference on Pain in Neurorehabilitation was constituted with the purpose identifying best practices for us in this context. Along with drug therapies and physical interventions, psychological treatments have been proven to be some of the most valuable tools that can be used within a multidisciplinary approach for fostering a reduction in pain intensity. However, there is a need to elucidate what forms of psychotherapy could be effectively matched with the specific pathologies that are typically addressed by neurorehabilitation teams. OBJECTIVES: To extensively assess the available evidence which supports the use of psychological therapies for pain reduction in neurological diseases. METHODS: A systematic review of the studies evaluating the effect of psychotherapies on pain intensity in neurological disorders was performed through an electronic search using PUBMED, EMBASE, and the Cochrane Database of Systematic Reviews. Based on the level of evidence of the included studies, recommendations were outlined separately for the different conditions. RESULTS: The literature search yielded 2352 results and the final database included 400 articles. The overall strength of the recommendations was medium/low. The different forms of psychological interventions, including Cognitive-Behavioral Therapy, cognitive or behavioral techniques, Mindfulness, hypnosis, Acceptance and Commitment Therapy (ACT), Brief Interpersonal Therapy, virtual reality interventions, various forms of biofeedback and mirror therapy were found to be effective for pain reduction in pathologies such as musculoskeletal pain, fibromyalgia, Complex Regional Pain Syndrome, Central Post-Stroke pain, Phantom Limb Pain, pain secondary to Spinal Cord Injury, multiple sclerosis and other debilitating syndromes, diabetic neuropathy, Medically Unexplained Symptoms, migraine and headache. CONCLUSIONS: Psychological interventions and psychotherapies are safe and effective treatments that can be used within an integrated approach for patients undergoing neurological rehabilitation for pain. The different interventions can be specifically selected depending on the disease being treated. A table of evidence and recommendations from the Italian Consensus Conference on Pain in Neurorehabilitation is also provided in the final part of the pape
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