33 research outputs found

    SG-classes, singular symplectic geoemtry, and order preserving isomorphisms

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    Die geometrischen KalkĂŒle von Pseudo-differenzial- und Fourier-Integraloperatoren beruhen auf den symplektischen Eigenschaften des KotangentialbĂŒndels. Um neue KalkĂŒle zu entwickeln, die an eine besondere Geometrie angepasst sind, ist es nötig, singulĂ€r-symplektische Mannigfaltigkeiten zu betrachten. Diese mĂŒssen zuerst verstanden werden, bevor man die zugehorigen OperatorkalkĂŒle konstruieren kann. In dieser Dissertation geben wir neue Einblicke in die singulĂ€r-symplektischen Strukturen, die aus asymptotisch-Euklidischen Mannigfaltigkeiten entstehen. Insbesondere rechnen wir aus, wie die Poisson-Klammer auf SG-Pseudo-Differenzialoperatoren wirkt, und definieren eine neue Klasse symplektischer Abbildungen, die an die geometrischen Besonderheiten angepasst sind. Wir betrachten außerdem die ordnungserhaltenden Isomorphismen der SG-Algebra und zeigen, dass unser Konzept von singulĂ€r-symplektischen Abbildungen natĂŒrlich in diesem Zusammenhang auftaucht. Wir benutzen es, um diese Isomorphismen als Konjugation mit einem SG-Fourier-Integraloperator zu charakterisieren.The geometric theory of pseudo-differential and Fourier Integral Operators relies on the symplectic structure of cotangent bundles. If one is to study calculi with some specific feature adapted to a geometric situation, the corresponding notion of cotangent bundle needs to be adapted as well and leads to spaces with a singular symplectic structure. Analysing these singularities is a necessary step in order to construct the calculus itself. In this thesis we provide some new insights into the symplectic structures arising from asymptotically Euclidean manifolds. In particular, we study the action of the Poisson bracket on SG-pseudo-differential operators and define a new class of singular symplectomorphisms, taking into account the geometric picture. We then consider this notion in the context of the characterisation of order-preserving isomorphisms of the SG-algebra, and show that these are in fact given by conjugation with a Fourier Integral Operator of SG-type

    Reliable Fast (20 Hz) Acquisition Rate by a TD fNIRS Device: Brain Resting-State Oscillation Studies

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    A high power setup for multichannel time-domain (TD) functional near infrared spectroscopy (fNIRS) measurements with high efficiency detection system was developed. It was fully characterized based on international performance assessment protocols for diffuse optics instruments, showing an improvement of the signal-to-noise ratio (SNR) with respect to previous analogue devices, and allowing acquisition of signals with sampling rate up to 20 Hz and source-detector distance up to 5 cm. A resting-state measurement on the motor cortex of a healthy volunteer was performed with an acquisition rate of 20 Hz at a 4 cm source-detector distance. The power spectrum for the cortical oxy- and deoxyhemoglobin is also provided

    How future surgery will benefit from SARS-COV-2-related measures: a SPIGC survey conveying the perspective of Italian surgeons

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    COVID-19 negatively affected surgical activity, but the potential benefits resulting from adopted measures remain unclear. The aim of this study was to evaluate the change in surgical activity and potential benefit from COVID-19 measures in perspective of Italian surgeons on behalf of SPIGC. A nationwide online survey on surgical practice before, during, and after COVID-19 pandemic was conducted in March-April 2022 (NCT:05323851). Effects of COVID-19 hospital-related measures on surgical patients' management and personal professional development across surgical specialties were explored. Data on demographics, pre-operative/peri-operative/post-operative management, and professional development were collected. Outcomes were matched with the corresponding volume. Four hundred and seventy-three respondents were included in final analysis across 14 surgical specialties. Since SARS-CoV-2 pandemic, application of telematic consultations (4.1% vs. 21.6%; p < 0.0001) and diagnostic evaluations (16.4% vs. 42.2%; p < 0.0001) increased. Elective surgical activities significantly reduced and surgeons opted more frequently for conservative management with a possible indication for elective (26.3% vs. 35.7%; p < 0.0001) or urgent (20.4% vs. 38.5%; p < 0.0001) surgery. All new COVID-related measures are perceived to be maintained in the future. Surgeons' personal education online increased from 12.6% (pre-COVID) to 86.6% (post-COVID; p < 0.0001). Online educational activities are considered a beneficial effect from COVID pandemic (56.4%). COVID-19 had a great impact on surgical specialties, with significant reduction of operation volume. However, some forced changes turned out to be benefits. Isolation measures pushed the use of telemedicine and telemetric devices for outpatient practice and favored communication for educational purposes and surgeon-patient/family communication. From the Italian surgeons' perspective, COVID-related measures will continue to influence future surgical clinical practice

    Prognostic indicators and outcomes of hospitalised COVID-19 patients with neurological disease: An individual patient data meta-analysis

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    BACKGROUND: Neurological COVID-19 disease has been reported widely, but published studies often lack information on neurological outcomes and prognostic risk factors. We aimed to describe the spectrum of neurological disease in hospitalised COVID-19 patients; characterise clinical outcomes; and investigate factors associated with a poor outcome. METHODS: We conducted an individual patient data (IPD) meta-analysis of hospitalised patients with neurological COVID-19 disease, using standard case definitions. We invited authors of studies from the first pandemic wave, plus clinicians in the Global COVID-Neuro Network with unpublished data, to contribute. We analysed features associated with poor outcome (moderate to severe disability or death, 3 to 6 on the modified Rankin Scale) using multivariable models. RESULTS: We included 83 studies (31 unpublished) providing IPD for 1979 patients with COVID-19 and acute new-onset neurological disease. Encephalopathy (978 [49%] patients) and cerebrovascular events (506 [26%]) were the most common diagnoses. Respiratory and systemic symptoms preceded neurological features in 93% of patients; one third developed neurological disease after hospital admission. A poor outcome was more common in patients with cerebrovascular events (76% [95% CI 67-82]), than encephalopathy (54% [42-65]). Intensive care use was high (38% [35-41]) overall, and also greater in the cerebrovascular patients. In the cerebrovascular, but not encephalopathic patients, risk factors for poor outcome included breathlessness on admission and elevated D-dimer. Overall, 30-day mortality was 30% [27-32]. The hazard of death was comparatively lower for patients in the WHO European region. INTERPRETATION: Neurological COVID-19 disease poses a considerable burden in terms of disease outcomes and use of hospital resources from prolonged intensive care and inpatient admission; preliminary data suggest these may differ according to WHO regions and country income levels. The different risk factors for encephalopathy and stroke suggest different disease mechanisms which may be amenable to intervention, especially in those who develop neurological symptoms after hospital admission

    Prognostic indicators and outcomes of hospitalised COVID-19 patients with neurological disease: An individual patient data meta-analysis.

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    BackgroundNeurological COVID-19 disease has been reported widely, but published studies often lack information on neurological outcomes and prognostic risk factors. We aimed to describe the spectrum of neurological disease in hospitalised COVID-19 patients; characterise clinical outcomes; and investigate factors associated with a poor outcome.MethodsWe conducted an individual patient data (IPD) meta-analysis of hospitalised patients with neurological COVID-19 disease, using standard case definitions. We invited authors of studies from the first pandemic wave, plus clinicians in the Global COVID-Neuro Network with unpublished data, to contribute. We analysed features associated with poor outcome (moderate to severe disability or death, 3 to 6 on the modified Rankin Scale) using multivariable models.ResultsWe included 83 studies (31 unpublished) providing IPD for 1979 patients with COVID-19 and acute new-onset neurological disease. Encephalopathy (978 [49%] patients) and cerebrovascular events (506 [26%]) were the most common diagnoses. Respiratory and systemic symptoms preceded neurological features in 93% of patients; one third developed neurological disease after hospital admission. A poor outcome was more common in patients with cerebrovascular events (76% [95% CI 67-82]), than encephalopathy (54% [42-65]). Intensive care use was high (38% [35-41]) overall, and also greater in the cerebrovascular patients. In the cerebrovascular, but not encephalopathic patients, risk factors for poor outcome included breathlessness on admission and elevated D-dimer. Overall, 30-day mortality was 30% [27-32]. The hazard of death was comparatively lower for patients in the WHO European region.InterpretationNeurological COVID-19 disease poses a considerable burden in terms of disease outcomes and use of hospital resources from prolonged intensive care and inpatient admission; preliminary data suggest these may differ according to WHO regions and country income levels. The different risk factors for encephalopathy and stroke suggest different disease mechanisms which may be amenable to intervention, especially in those who develop neurological symptoms after hospital admission

    Jean-Marie Guyau notre contemporain

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    La philosophie de la vie de Jean-Marie Guyau (1854-1888) reprĂ©sente l’une des perspectives les plus originales de son temps dans les domaines de l’éthique, de l’esthĂ©tique et des Ă©tudes sociologiques. Cependant, malgrĂ© son influence sur des auteurs comme Nietzsche, Bergson, Durkheim et Kropotkine, cet auteur a Ă©tĂ© considĂ©rĂ© comme peu important dans l’histoire de la philosophie française. Ce livre, auquel ont contribuĂ© les plus grands spĂ©cialistes de Guyau, vise Ă  redĂ©couvrir l’actualitĂ© de sa pensĂ©e, en posant une question fondamentale : qui sont les vĂ©ritables contemporains de Guyau ? Guyau reste-t-il un auteur de la seconde moitiĂ© du XIXe siĂšcle, dont l’Ɠuvre a Ă©tĂ© accomplie par un Nietzsche et un Bergson ; ou, au contraire, est-elle d’une actualitĂ© qui n’a pas Ă©tĂ© suffisamment prise en compte en son temps et qui appartient, d’un point de vue conceptuel, Ă  notre XXIe siĂšcle ? Le livre s’adresse Ă  la fois aux spĂ©cialistes de la philosophie française du XIXe siĂšcle et, d’une maniĂšre plus gĂ©nĂ©rale, Ă  ceux et celles qui s’intĂ©ressent aux itinĂ©raires philosophiques non linĂ©aires et non conventionnels.The philosophy of life according to Jean-Marie Guyau (1854-1888) offers one of the most original perspectives of his time in the fields of ethics, aesthetics and sociological studies. However, despite his influence on authors such as Nietzsche, Bergson, Durkheim and Kropotkin, he has been deemed of little importance in the history of French philosophy. This book, to which the greatest specialists of Guyau have contributed, aims to rediscover the relevance of his thought, by asking a fundamental question: who are Guyau’s true contemporaries? Is Guyau merely an author of the second half of the 19th century, whose work was completed by Nietzsche and Bergson; or, on the contrary, is his work of a topicality that was not sufficiently acknowledged at the time and that belongs, from a conceptual point of view, to our 21st century? The book is intended both for specialists in nineteenth-century French philosophy and, more generally, for anyone interested in non-linear and unconventional philosophical itineraries

    Renal function and peak exercise oxygen consumption in chronic heart failure with reduced left ventricular ejection fraction

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    Background: Chronic kidney disease is associated with sympathetic activation and muscle abnormalities, which may contribute to decreased exercise capacity. We investigated the correlation of renal function with peak exercise oxygen consumption (V˙O2) in heart failure (HF) patients. Methods and Results: We recruited 2,938 systolic HF patients who underwent clinical, laboratory, echocardiographic and cardiopulmonary exercise testing. The patients were stratified according to estimated glomerular filtration rate (eGFR). Mean follow-up was 3.7 years. The primary outcome was a composite of cardiovascular death and urgent heart transplantation at 3 years. On multivariable regression, eGFR was predictor of peakV˙O2 (P<0.0001). Other predictors were age, sex, body mass index, HF etiology, NYHA class, atrial fibrillation, resting heart rate, Btype natriuretic peptide, hemoglobin, and treatment. After adjusting for significant covariates, the hazard ratio for primary outcome associated with peakVO2 <12 ml ・ kg−1 ・ min−1 was 1.75 (95% confidence interval (CI): 1.06–2.91; P=0.0292) in patients with eGFR ≄60, 1.77 (0.87–3.61; P=0.1141) in those with eGFR of 45–59, and 2.72 (1.01– 7.37; P=0.0489) in those with eGFR <45 ml ・ min−1 ・ 1.73 m−2. The area under the receiver-operating characteristic curve for peakV˙O2 <12 ml ・ kg−1 ・ min−1 was 0.63 (95% CI: 0.54–0.71), 0.67 (0.56–0.78), and 0.57 (0.47–0.69), respectively. Testing for interaction was not significant. Conclusions: Renal dysfunction is correlated with peakV O2. A peakV O2 cutoff of 12 ml ・ kg–1 ・ min–1 offers limited prognostic information in HF patients with more severely impaired renal function

    The metabolic exercise test data combined with Cardiac and Kidney Indexes (MECKI) score and prognosis in heart failure. A validation study

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    BACKGROUND: The Metabolic Exercise test data combined with Cardiac and Kidney Indexes (MECKI) score is a prognostic model to identify heart failure (HF) patients at risk for cardiovascular mortality (CVM) and urgent heart transplantation (uHT) based on 6 routine clinical parameters: hemoglobin, sodium, kidney function by the Modification of Diet in Renal Disease (MDRD) equation, left ventricle ejection fraction (LVEF), percentage of predicted peak oxygen consumption (VO2) and VE/VCO2 slope. OBJECTIVES: MECKI score must be generalizable to be considered useful: therefore, its performance was validated in a new sequence of HF patients. METHODS: Both the development (MECKI-D) and the validation (MECKI-V) cohorts were composed of consecutive HF patients with LVEF <40% able to perform a symptom-limited cardiopulmonary exercise testing. The CVM or uHT rates were analyzed at one, two and three years in both cohorts: all patients with a censoring time shorter than the scheduled follow-up were excluded, while those with events occurring after 1, 2 and 3 years were considered as censored. RESULTS: MECKI-D and MECKI-V consisted of 2009 and 992 patients, respectively. MECKI-V patients had a higher LVEF, higher peak VO2 and lower VE/VCO2 slope, higher prescription of beta-blockers and device therapy: after the 3-year follow-up, CVM or uHT occurred in 206 (18%) MECKI-D and 44 (13%) MECKI-V patients (p<0.000), respectively. MECKI-V AUC values at one, two and three years were 0.81 \ub1 0.04, 0.76 \ub1 0.04, and 0.80 \ub1 0.03, respectively, not significantly different from MECKI-D. CONCLUSIONS: MECKI score preserves its predictive ability in a HF population at a lower risk

    Sex Profile and Risk Assessment With Cardiopulmonary Exercise Testing in Heart Failure: Propensity Score Matching for Sex Selection Bias

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    35In heart failure (HF), women show better survival despite a comparatively low peak oxygen consumption (V˙o2): this raises doubt about the accuracy of risk assessment by cardiopulmonary exercise testing (CPET) in women. Accordingly, we aimed to check (1) whether the predictive role of well-known CPET risk indexes, ie, peak V˙o2 and ventilatory response (V˙e/V˙co2 slope), is sex independent and (2) if sex-related characteristics that impact outcome in HF should be considered as associations that may confound the effect of sex on survival.nonenoneCorrà, Ugo; Agostoni, Piergiuseppe; Giordano, Andrea; Cattadori, Gaia; Battaia, Elisa; La Gioia, Rocco; Scardovi, Angela B; Emdin, Michele; Metra, Marco; Sinagra, Gianfranco; Limongelli, Giuseppe; Raimondo, Rosa; Re, Federica; Guazzi, Marco; Belardinelli, Romualdo; Parati, Gianfranco; Magrì, Damiano; Fiorentini, Cesare; Cicoira, Mariantonietta; Salvioni, Elisabetta; Giovannardi, Marta; Veglia, Fabrizio; Mezzani, Alessandro; Scrutinio, Domenico; Di Lenarda, Andrea; Ricci, Roberto; Apostolo, Anna; Iorio, Anna Maria; Paolillo, Stefania; Palermo, Pietro; Contini, Mauro; Vassanelli, Corrado; Passino, Claudio; Giannuzzi, Pantaleo; Piepoli, Massimo FCorrà, Ugo; Agostoni, Piergiuseppe; Giordano, Andrea; Cattadori, Gaia; Battaia, Elisa; La Gioia, Rocco; Scardovi, Angela B; Emdin, Michele; Metra, Marco; Sinagra, Gianfranco; Limongelli, Giuseppe; Raimondo, Rosa; Re, Federica; Guazzi, Marco; Belardinelli, Romualdo; Parati, Gianfranco; Magrì, Damiano; Fiorentini, Cesare; Cicoira, Mariantonietta; Salvioni, Elisabetta; Giovannardi, Marta; Veglia, Fabrizio; Mezzani, Alessandro; Scrutinio, Domenico; Di Lenarda, Andrea; Ricci, Roberto; Apostolo, Anna; Iorio, Anna Maria; Paolillo, Stefania; Palermo, Pietro; Contini, Mauro; Vassanelli, Corrado; Passino, Claudio; Giannuzzi, Pantaleo; Piepoli, Massimo

    Heart failure and anemia: Effects on prognostic variables

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    Anemia is frequent in heart failure (HF), and it is associated with higher mortality. The predictive power of established HF prognostic parameters in anemic HF patients is unknown
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