A non-linear observer for unsteady three-dimensional flows

A method is proposed to estimate the velocity field of an unsteady flow using a limited number of flow measurements. The method is based on a non-linear low-dimensional model of the flow and on expanding the velocity field in terms of empirical basis functions. The main idea is to impose that the coefficients of the modal expansion of the velocity field give the best approximation to the available measurements and that at the same time they satisfy as close as possible the non-linear low-order model. The practical use may range from feedback flow control to monitoring of the flow in non-accessible regions. The proposed technique is applied to the flow around a confined square cylinder, both in two- and three-dimensional laminar flow regimes. Comparisons are provided. with existing linear and non-linear estimation techniques

Clinical features and outcomes of elderly hospitalised patients with chronic obstructive pulmonary disease, heart failure or both

Background and objective: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) mutually increase the risk of being present in the same patient, especially if older. Whether or not this coexistence may be associated with a worse prognosis is debated. Therefore, employing data derived from the REPOSI register, we evaluated the clinical features and outcomes in a population of elderly patients admitted to internal medicine wards and having COPD, HF or COPD + HF. Methods: We measured socio-demographic and anthropometric characteristics, severity and prevalence of comorbidities, clinical and laboratory features during hospitalization, mood disorders, functional independence, drug prescriptions and discharge destination. The primary study outcome was the risk of death. Results: We considered 2,343 elderly hospitalized patients (median age 81 years), of whom 1,154 (49%) had COPD, 813 (35%) HF, and 376 (16%) COPD + HF. Patients with COPD + HF had different characteristics than those with COPD or HF, such as a higher prevalence of previous hospitalizations, comorbidities (especially chronic kidney disease), higher respiratory rate at admission and number of prescribed drugs. Patients with COPD + HF (hazard ratio HR 1.74, 95% confidence intervals CI 1.16-2.61) and patients with dementia (HR 1.75, 95% CI 1.06-2.90) had a higher risk of death at one year. The Kaplan-Meier curves showed a higher mortality risk in the group of patients with COPD + HF for all causes (p = 0.010), respiratory causes (p = 0.006), cardiovascular causes (p = 0.046) and respiratory plus cardiovascular causes (p = 0.009). Conclusion: In this real-life cohort of hospitalized elderly patients, the coexistence of COPD and HF significantly worsened prognosis at one year. This finding may help to better define the care needs of this population

Model and distribution uncertainty in Multivariate GARCH estimation: a Monte Carlo analysis

Multivariate GARCH models are in principle able to accommodate the features of the dynamic conditional correlations processes, although with the drawback, when the number of financial returns series considered increases, that the parameterizations entail too many parameters. In general, the interaction between model parametrization of the second conditional moment and the conditional density of asset returns adopted in the estimation determines the fitting of such models to the observed dynamics of the data. This paper aims to evaluate the interactions between conditional second moment specifications and probability distributions adopted in the likelihood computation, in forecasting volatilities and covolatilities. We measure the relative performances of alternative conditional second moment and probability distributions specifications by means of Monte Carlo simulations, using both statistical and financial forecasting loss functions

Model and distribution uncertainty in multivariate GARCH estimation: A Monte Carlo analysis

Multivariate GARCH models are in principle able to accommodate the features of the dynamic conditional covariances; nonetheless the interaction between model parametrization of the second conditional moment and the conditional density of asset returns adopted in the estimation determines the fitting of such models to the observed dynamics of the data. Alternative MGARCH specifications and probability distributions are compared on the basis of forecasting performances by means of Monte Carlo simulations, using both statistical and financial forecasting loss functions.

A novel calibration of the Large Piston Prover at INRIM

INRIM realizes its flow rate standard using three distinct facilities, aimed at measuring different flow rate ranges; in particular, for the larger flow range (10-2600 L/min) a piston of 1000 mm nominal diameter and 1200 mm nominal stroke is used. The traceability of the standard is obtained through dimensional calibration of the piston, regarding both the piston size and its stroke. The first calibration of the machine was performed at its initial installation. Even if most of the relevant documentation about this first calibration is not available, INRIM realized a procedure similar to the old one and performed measurements to renovate the first facility calibration. The present paper will dedicate special attention to the description of the measurement chain used for the calibration of the piston in its own siege. Moreover, the method for the transfer of traceability from the length standard to the measurement of the piston diameter will be discussed; it should be noted that the dimensional study is not completed yet, because the first set of measurements described in the present work, evidenced the criticalities of the procedure adopted in the past. For this aim, a further measurement campaign will be carried out in order to minimize the uncertainty associated to the dimensional measurement of the piston and of its displacement. Finally, the results of first dimensional evaluation will be presented alongside

Vaginal delivery in SARS-CoV-2-infected pregnant women in Northern Italy: a retrospective analysis

Objective: To report mode of delivery and immediate neonatal outcome in women infected with COVID-19. Design: Retrospective study. Setting: Twelve hospitals in northern Italy. Participants: Pregnant women with COVID-19-confirmed infection who delivered. Exposure: COVID 19 infection in pregnancy. Methods: SARS-CoV-2-infected women who were admitted and delivered from 1 to 20 March 2020 were eligible. Data were collected from the clinical records using a standardised questionnaire on maternal general characteristics, any medical or obstetric co-morbidity, course of pregnancy, clinical signs and symptoms, treatment of COVID 19 infection, mode of delivery, neonatal data and breastfeeding. Main outcome and measures: Data on mode of delivery and neonatal outcome. Results: In all, 42 women with COVID-19 delivered at the participating centres; 24 (57.1%, 95% CI 41.0–72.3) delivered vaginally. An elective caesarean section was performed in 18/42 (42.9%, 95% CI 27.7–59.0) cases: in eight cases the indication was unrelated to COVID-19 infection. Pneumonia was diagnosed in 19/42 (45.2%, 95% CI 29.8–61.3) cases: of these, 7/19 (36.8%, 95% CI 16.3–61.6) required oxygen support and 4/19 (21.1%, 95% CI 6.1–45.6) were admitted to a critical care unit. Two women with COVID-19 breastfed without a mask because infection was diagnosed in the postpartum period: their newborns tested positive for SARS-Cov-2 infection. In one case, a newborn had a positive test after a vaginal operative delivery. Conclusions: Although postpartum infection cannot be excluded with 100% certainty, these findings suggest that vaginal delivery is associated with a low risk of intrapartum SARS-Cov-2 transmission to the newborn. Tweetable abstract: This study suggests that vaginal delivery may be associated with a low risk of intrapartum SARS-Cov-2 transmission to the newborn

Vaginal delivery in SARS-CoV-2-infected pregnant women in Northern Italy: a retrospective analysis

Objective: To report mode of delivery and immediate neonatal outcome in women infected with COVID-19. Design: Retrospective study. Setting: Twelve hospitals in northern Italy. Participants: Pregnant women with COVID-19-confirmed infection who delivered. Exposure: COVID 19 infection in pregnancy. Methods: SARS-CoV-2-infected women who were admitted and delivered from 1 to 20 March 2020 were eligible. Data were collected from the clinical records using a standardised questionnaire on maternal general characteristics, any medical or obstetric co-morbidity, course of pregnancy, clinical signs and symptoms, treatment of COVID 19 infection, mode of delivery, neonatal data and breastfeeding. Main outcome and measures: Data on mode of delivery and neonatal outcome. Results: In all, 42 women with COVID-19 delivered at the participating centres; 24 (57.1%, 95% CI 41.0–72.3) delivered vaginally. An elective caesarean section was performed in 18/42 (42.9%, 95% CI 27.7–59.0) cases: in eight cases the indication was unrelated to COVID-19 infection. Pneumonia was diagnosed in 19/42 (45.2%, 95% CI 29.8–61.3) cases: of these, 7/19 (36.8%, 95% CI 16.3–61.6) required oxygen support and 4/19 (21.1%, 95% CI 6.1–45.6) were admitted to a critical care unit. Two women with COVID-19 breastfed without a mask because infection was diagnosed in the postpartum period: their newborns tested positive for SARS-Cov-2 infection. In one case, a newborn had a positive test after a vaginal operative delivery. Conclusions: Although postpartum infection cannot be excluded with 100% certainty, these findings suggest that vaginal delivery is associated with a low risk of intrapartum SARS-Cov-2 transmission to the newborn. Tweetable abstract: This study suggests that vaginal delivery may be associated with a low risk of intrapartum SARS-Cov-2 transmission to the newborn

How often are endometrial polyps malignant in asymptomatic postmenopausal women? A multicenter study

OBJECTIVE: The objective of the study was to evaluate the prevalence of cancer and premalignant lesions in polyps on atrophic endometrium in asymptomatic postmenopausal women to compare these findings with a similar cohort of patients with abnormal uterine bleeding. STUDY DESIGN: One thousand one hundred fifty-two asymptomatic and 770 consecutive postmenopausal women with abnormal uterine bleeding were included in a retrospective multicenter study. Recruited patients underwent hysteroscopic polypectomy based on a sonohysterographic or hysteroscopic diagnosis. The pathologic report was the main outcome measure. RESULTS: One single case of stage 1 grade 1 endometrial carcinoma on a polyp with a mean diameter of 40 mm (0.1%) was observed in asymptomatic women. This prevalence was 10 times lower than in symptomatic patients (P 18 mm, 6.9; confidence interval, 2.2-21.4). CONCLUSION: Follow-up and/or treatment of endometrial polyps incidentally diagnosed in asymptomatic postmenopausal patients could be safely restricted to few selected cases based on polyp diameter