INVESTIGATING THE SEISMIC RESPONSE OF URM WALLS WITH IRREGULAR OPENING LAYOUT THROUGH DIFFERENT MODELING APPROACHES

The façade and internal walls of unreinforced masonry (URM) buildings often present an irregular opening layout, due to architectural reasons or modifications to the structure, which make the expected seismic damage pattern less predictable a priori. Therefore, the discretization of the walls in structural components is not standardized, conversely to cases with a regular opening layout for which the available modeling methods are corroborated by seismic damage surveys reporting recurrent failure patterns. The structural component discretization is a relevant step for the code-conforming seismic assessment, typically based on comparing the internal forces and drifts of each component to strength criteria and drift thresholds. Therefore, the lack of well-established approaches can significantly influence the assessment. The issue is even more evident when the structural components must be identified a priori in the modeling stage, namely for equivalent frame models. The applicability of available methods for discretization of URM walls with irregular opening layout has been already investigated in literature, but a conclusive judgment requires further studies. In this context, this paper presents an overview of the preliminary results addressing the numerical modeling of this type of walls within the framework of the DPC-ReLUIS 2022-2024 project (Subtask 10.3), funded by the Italian Department of Civil Protection. The Subtask aims to propose consensus-based recommendations for researchers and practitioners which can contribute to harmonize the use of different modeling approaches. Seven research groups are involved in the research, adopting different modeling approaches and computer codes, but similar assumptions and the same analysis method (pushover) are used. The benchmark URM structure illustrated in the paper is a two-story wall from which four configurations with increasing irregularity of opening layout were derived. The results of four modeling approached are presented. Three of them reproduce the mechanical response of masonry at the material scale by means of FE models implemented in OpenSees, DIANA and Abaqus software, while the remaining approach describes the mechanical response of masonry at the macro-element scale in 3DMacro software. Results were compared in terms of capacity curves, predicted failure mechanisms and evolution of internal forces in piers. The adoption of consistent assumptions among the different approaches led to an overall agreement of predictions at both wall and pier scales, particularly in terms of damage pattern with higher concentration of damage at the ground story. Despite that, differences on the pushover curves have been highlighted. They are mainly due to some deviations of the internal forces in squat piers deriving from a complex load flow in these elements

The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry

The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations

Institutional investors and corporate governance

We provide a comprehensive overview of the role of institutional investors in corporate governance with three main components. First, we establish new stylized facts documenting the evolution and importance of institutional ownership. Second, we provide a detailed characterization of key aspects of the legal and regulatory setting within which institutional investors govern portfolio firms. Third, we synthesize the evolving response of the recent theoretical and empirical academic literature in finance to the emergence of institutional investors in corporate governance. We highlight how the defining aspect of institutional investors – the fact that they are financial intermediaries – differentiates them in their governance role from standard principal blockholders. Further, not all institutional investors are identical, and we pay close attention to heterogeneity amongst institutional investors as blockholders

The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry

The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations

Long-term results of polytetrafluoroethylene versus saphenous vein repair of degenerative carotid artery aneurysm

Objective: To compare the results of polytetrafluoroethylene (PTFE) and great saphenous vein (GSV) bypass after resection of a degenerative aneurysm of the carotid artery. Methods: From January 1994 to November 2017, 37 patients (27 men) with a mean age of 58 years (range, 39-82 years) with a degenerative aneurysm of the carotid artery (median diameter, 28 mm; range, 19-42 mm), underwent resection of the aneurysm followed by a bypass with either a GSV (n = 10) or a PTFE prosthesis (n = 27). Although 31 patients were asymptomatic, 6 patients were symptomatic: transient ischemic attack (n = 4), minor stroke (n = 1), and compression of the hypoglossal nerve (n = 1). The preoperative workup included duplex ultrasound examination of the arteries to the head, and angiography or computed tomography angiography. All patients were operated under general anesthesia and six were intubated through the nose. Sixteen patients were monitored through transcutaneous oximetry. No shunt was used in this series. In 10 patients receiving a PTFE graft, the external carotid artery was implanted in the prosthesis. Mean follow-up was 16.9 ± 2 years (95% confidence interval, 14.5-19.3 years). Primary end points were the 30-day combined stroke/death rate, graft infection, late graft patency, and late stroke-free survival. Secondary end points were cranial nerve injury and length of postoperative hospital stay. Results: Postoperative mortality was nil in both groups. One postoperative stroke was observed in the PTFE group, whereas none occurred in the GSV group (P =.84). No graft infection was observed in either group. At 10 years, survival in the GSV group was 80 ± 12%, and survival in the PTFE group was 76 ± 8% (log-rank [Mantel-Cox], P =.85). In the GSV group, graft patency at 7 and 10 years was 85 ± 13%. In the PTFE group B, graft patency was 100% (log-rank [Mantel-Cox], P =.12). No late stroke was observed. Two transient cranial nerve injuries were observed in the GSV group (20%) and two in the PTFE group (8%) (P =.97). Length of hospital stay was comparable in both groups (GSV group, 6 days; PTFE group, 5 days; P =.12). Conclusions: This study suggests that, after resection of a degenerative aneurysm of the carotid artery, bypass with a PTFE prosthesis gives comparable results to those obtained with the GSV. We recommend sparing the GSV and instead using a PTFE prosthesis in patients with a degenerative aneurysm of the carotid artery

Intravascular ultrasound-assisted endovascular exclusion of penetrating aortic ulcers

Background: Penetrating aortic ulcer (PAU) is an atherosclerotic lesion penetrating the elastic lamina and extending into the media of the aorta. It may evolve into intramural hematoma, focal dissection, pseudoaneurysm, and eventually rupture. The purpose of this study was to evaluate the effectiveness of a totally intravascular ultrasound (IVUS)-assisted endovascular exclusion of PAU. Methods: Thirteen consecutive patients (median age 66 years) underwent IVUS-assisted endovascular exclusion of PAU. The primary end points were fluoroscopy time, radiation dose, and occurrence of type I primary endoleak. Secondary end points were postoperative mortality and morbidity, arterial access complications, postoperative length of stay in the hospital, and occurrence of type II endoleaks. Results: The median fluoroscopy time was 4 min (4–5). The median radiation dose was 4.2 mGy (3.9–4.5). A proximal and distal landing zone of at least 2 cm could be obtained in all the patients. No patient presented a type I endoleak. No postoperative mortality, no morbidity, or arterial access complication was observed. The median length of postoperative stay in the hospital was 2 days (2–3). The median length of follow-up was 25 months (9.2–38.7). One late type II endoleak was observed (7.7%), because of reflux from the intercostal arteries, without the need for additional treatment. Conclusions: IVUS-assisted endovascular treatment of PAU allows durable exclusion of PAU with a short fluoroscopy time and no need for injection of contrast media. Further series are needed to confirm the results of this preliminary study

Changes in prostate cancer detection rate of MRI-TRUS fusion vs systematic biopsy over time: Evidence of a learning curve

© 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved. Background:To determine the effect of urologist and radiologist learning curves and changes in MRI-TRUS fusion platform during 9 years of NCI\u27s experience with multiparametric magnetic resonance imaging (mpMRI)/TRUS fusion biopsy.Methods:A prospectively maintained database of patients undergoing mpMRI followed by fusion biopsy (Fbx) and systematic biopsy (Sbx) from 2007 to 2016 was reviewed. The patients were stratified based on the timing of first biopsy. Cohort 1 (7/2007 d for learning curve. Cohort 2 (1/2011-5/2013) and cohort 3 (5/2013-4/2016) included patients biopsied prior to and after debut of a new software platform, respectively. Clinically significant (CS) disease was defined as Gleason 7 (3+4) or higher. McNemar\u27s test compared cancer detection rates (CDRs) of Sbx and Fbx between time periods.Results:1528 patients were included in the study with 230, 537 and 761 patients included in three respective cohorts. Median age (interquartile range) was 61.0 (±9.0), 62.0 (±7.3), and 64.0 (±11.0) years in three cohorts, respectively (P\u3c0.001). Fbx and Sbx had comparable CS CDR in cohort 1 (24.8 vs 22.2%, P=0.377). Fbx detected significantly more CS disease compared to Sbx in the following two periods (cohort 2: 31.5 vs 25.0%, P=0.001; cohort 3: 36.4 vs 30.3%, P\u3c0.001) and detected significantly less low risk disease in the same period (cohort 2: 14.5 vs 19.6%, P\u3c0.001; cohort 3: 12.6 vs 16.7%, P\u3c0.001). Even after multivariate adjustment with age, PSA, race, clinical stage and MRI suspicion score, Fbx CS cancer detection increased in successive cohorts (cohort 2: OR 2.23, P=0.043; cohort 3: OR 2.92, P=0.007).Conclusions:In the past 9 years, there has been significant improvement in the accuracy of Fbx. Our results show that after an early learning period, Fbx detected higher rates of CS cancer and lower rates of clinically insignificant cancer than Sbx. Software advances allowed for even greater detection of CS disease