Ultrafast Molecular Imaging by Laser Induced Electron Diffraction

We address the feasibility of imaging geometric and orbital structure of a polyatomic molecule on an attosecond time-scale using the laser induced electron diffraction (LIED) technique. We present numerical results for the highest molecular orbitals of the CO2 molecule excited by a near infrared few-cycle laser pulse. The molecular geometry (bond-lengths) is determined within 3% of accuracy from a diffraction pattern which also reflects the nodal properties of the initial molecular orbital. Robustness of the structure determination is discussed with respect to vibrational and rotational motions with a complete interpretation of the laser-induced mechanisms

Signal Processing Methodology of Response Data from a Historical Arch Bridge toward Reliable Modal Identification

The paper is part of a case study concerning the structural assessment of a historical infrastructure in the local territory, a road three-span reinforced concrete arch bridge over a river, built by the end of World War I (1917). The purpose of the paper is twofold: first, in-situ acquired response data are systematically analysed by specific signal processing techniques, to form a devoted methodological procedure and to extract useful information toward possible interpretation of the current structural conditions; second, the deciphered information is elaborated, in view of obtaining peculiar conceptualisations of detailed features of the structural response, as meant to achieve quantitative descriptions and modelling, for final Structural Health Monitoring (SHM) and intervention purposes. The proposed methodology, integrating self-implemented and adapted classical signal processing methods, and refined techniques, such as Wavelet analysis and ARMA models, assembles a rather general, systematic methodological approach to signal processing, highlighting the capability to extract useful and fundamental information from acquired response data, also endowed of a non-stationary character, toward final structural interpretation, identification and modelling, thus enabling for developing a reliable and effective SHM platform, on strategic ageing infrastructures. For the present case study, non-stationary characteristics of the response signals are revealed and flattened out, to identify the underlying fundamental frequencies of the infrastructure and to advance particular interpretations of its current structural behaviour, in forming an enlarging structural consciousness of the bridge at hand

Femtosecond spectroscopic study of carminic acid–DNA interactions

Photo-excited carminic acid and carminic acid–DNA complexes in a buffer solution at pH 7 have been examined using a variety of spectroscopy techniques, that are in particular, the femtosecond resolved fluorescence upconversion and transient absorption spectroscopy. The observation of dual fluorescence emission, one peaks at 470 nm and the other at 570 nm, indicates to an excited-state (S1) intramolecular proton transfer (ESIPT). A detailed analysis of the transient absorption measurements of an aqueous carminic-acid solution at pH 7 yielded four lifetimes for the excited-state (S1): 8, 15, 33 and 46 ps. On the other hand, only two lifetimes, 34 and 47 ps, were observed by fluorescence upconversion spectroscopy because of the detection limitation to the long wavelength edge of the carminic-acid spectrum. The four S1 lifetimes were ascribed to the coexistence of respectively two tautomer (normal and tautomer) forms of carminic acid, in the non-dissociated state (CAH) and in the deprotonated state (CA−). The fluorescence upconversion measurements of carminic acid–DNA complexes exhibited a prolongation of the fluorescence lifetimes. This effect was accepted as evidence for the formation of intercalation complexes between the carminic acid and the DNA. The intercalative binding of the carminic acid to DNA was confirmed by the fluorescence titration experiments resulting to a binding constant of 2 × 105 M−1 that is typical for anthracycline–DNA complexes

Effects of lockdown on emergency room admissions for psychiatric evaluation: an observational study from the AUSL Romagna, Italy

Objectives: An observation of the admissions to the emergency room (ER) requiring psychiatric evaluation during the lockdown and investigation of the demographic and clinical variables. Methods: Retrospective longitudinal observational study of ER accesses for psychiatric evaluation was performed, comparing two periods (9 March–3 May 2020 vs. 9 March–3 May 2019). Data (number of admissions, key baseline demographic and clinical variables) were extracted from the ER databases of referral centres in a well-defined geographic area of North-Eastern Italy (Cesena, Ravenna, Forlì, and Rimini). Results: A 15% reduction of psychiatric referrals was observed, together with a 17% reduction in the total number of patients referring to the ER. This reduction was most evident in the first month of the lockdown period (almost 25% reduction of both referrals and patients). Female gender (OR: 1.52: 95%, CI: 1.12–2.06) and being a local resident (OR: 1.54: 95%CI: 1.02–2.34) were factors associated with the decrease. Conclusions: Lockdown changed dramatically health priorities in the local population, including people with mental health. We speculate that our observations do not only refer to the confinement due to the lockdown regime but also to fear of contagion and adoption of different coping strategies, especially in women.Key-points During lockdown 15% reduction of psychiatric visits and >17% reduction in the number of psychiatric patients referring to the ER was observed. in the first four weeks of the lockdown almost 25% reduction of both visits and patients was observed Female gender and being a local resident were factors associated with the decrease

Mid-term psychiatric consequences of the COVID-19 pandemic: a 4 months observational study on emergency room admissions for psychiatric evaluation after the (first) lockdown period in Italy

Purpose: The aim of our study is to evaluate the number and the features of admissions to the emergency room (ER) requiring psychiatric consultation, in the period between May 4th and August 31st 2020. Methods: We carried out a retrospective longitudinal observational study examining the 4 months following the initial lockdown imposed during the COVID-19 outbreak (May 4th and August 31st 2020). More specifically, the ER admissions leading to psychiatric referral were reviewed at all seven public hospitals of AUSL Romagna (Emilia Romagna region, Italy). Socio-demographic variables, history of medical comorbidities or psychiatric disorders, reason for ER admission, psychiatric diagnosis at discharge, and actions taken by the psychiatrist were collected. Results: An 11.3% (p = 0.007) increase in psychiatric assessments was observed when compared with the same period of the previous year (2019). A positive personal history of psychiatric disorders (OR:0.68, CI: 0.53–0.87) and assessments leading to no indication for follow-up (OR: 0.22, CI: 0.13–0.39) were significantly less frequent, while there was a significant increase of cases featuring organic comorbidities (OR: 1.24, CI: 1.00–1.52) and suicidal ideation/self-harm/suicide attempt (OR: 1,71, CI: 1.19–2.45) or psychomotor agitation (OR: 1.46, CI: 1.02–2.07) as reason for admission. Conclusions: Our results showed an increase in ER psychiatric consultations compared to the previous year, underlying the increased psychological distress caused by the lockdown

Strong field double ionization of H2 : Insights from nonlinear dynamics

The uncorrelated (``sequential'') and correlated (``nonsequential'') double ionization of the H2 molecule in strong laser pulses is investigated using the tools of nonlinear dynamics. We focus on the phase-space dynamics of this system, specifically by finding the dynamical structures that regulate these ionization processes. The emerging picture complements the recollision scenario by clarifying the distinct roles played by the recolliding and core electrons. Our analysis leads to verifiable predictions of the intensities where qualitative changes in ionization occur. We also show how these findings depend on the internuclear distance