In seismic-prone regions, assessment of the risk of regional bridge networks is essential for quantifying resilience metrics. Ideally this assessment needs to rely on high-fidelity numerical simulation models and on a comprehensive quantification of the seismic hazard. Unfortunately, the computational burden associated with such a faithful assessment of risk across the bridge portfolio is prohibitive for larger networks. This study investigates the use of a Gaussian Process (GP)-based stochastic emulation framework to alleviate this burden. A single surrogate model is established across all bridges of the same typology in the network. The surrogate model development accounts for diverse bridge configurations, as well as aleatoric ground motion variability across different intensity levels. The implementation also addresses aleatoric correlations across different engineering demand parameters for each bridge. The framework is implemented for risk assessment of the Chilean bridge network, specifically for four different bridge typologies, representing the predominant configurations within the national bridge inventory. It also examines in detail the computational benefits of establishing a single surrogate model across each typology, by comparing its accuracy to an application that considers the development of separate surrogate models per bridge type. The case study validates the accuracy of the stochastic emulation framework and illustrates the computational benefits for regional risk assessment. The latter is accomplished by comparing the results to different approximate formulations with respect to the assumptions for modeling the bridges within the network or the fidelity for considering and propagating the different types of uncertainties impacting the risk estimation.
Osteoporotic vertebral fractures (OVFs) are the second most common fractures in osteoporosis, often leading to reduced functional capacity, chronic pain, and lower quality of life. Physical exercise and health education are considered promising options for managing these symptoms. To determine the effectiveness and safety of exercise and health education compared to usual care in patients with OVFs. A literature search up to April 2024 was conducted in PubMed, Scopus, Web of Science, and the Cochrane Library. Clinical trials involving adults with OVFs were included, focusing on physical capacity (primary outcome) and other health outcomes. Study selection, bias assessment, and data extraction were independently conducted by two authors, with a third author resolving conflicts. Nineteen studies were included in the meta-analysis of exercise interventions. Exercise interventions were analyzed using a standardized mean difference (SMD) meta-analysis, with additional sensitivity analyses. Physical exercise significantly improves functional capacity (SMD −0.41; 95
The vasopressor test (VPT) has been proposed to evaluate changes in tissue perfusion in response to a transient, vasopressor-induced increase in mean arterial blood pressure (MAP). However, the physiological determinants of this response remain unclear. To (1) evaluate capillary refill time (CRT) response to standardized VPT, (2) explore the associations between CRT and splanchnic vascular Doppler indices, and (3) identify baseline hemodynamic predictors of CRT improvement. In this prospective multicenter study, 32 septic shock patients with persistent hypoperfusion and preload unresponsiveness underwent a VPT, increasing MAP from 65 to 85 mmHg. CRT responders were defined as those with a decrease of ≥ 1 s. Visceral Doppler resistive indices were measured to assess regional perfusion. Baseline hemodynamic variables were evaluated as predictors of CRT improvement. Logistic regression and mixed-effects models examined the associations between CRT, stroke volume, and baseline hemodynamics. Eleven patients (34
The thymus is one of the primary immune organs in childhood. During embryonic development, the migration of the thymus from the cervical region to the mediastinum coincides with the formation of other structures in the anterior cervical region, which can result in anomalous thymic locations. Among these, the most frequent are cervical remnants of accessory thymic tissue along the normal migration path and thymic extensions that project beyond their usual location. Ectopic locations, which deviate from the normal embryological course, are less common. Radiologists must recognize these variants and their imaging manifestations to avoid misdiagnosis and incorrect interventions. This article aims to review and illustrate, using imaging, the embryology, normal development, anatomy, and the most common locations of thymic tissue outside its normal position in the anterior mediastinum in children.
The management of upper cervical spine (UCS) fractures is unclear concerning the role of fusion versus non-fusion fixation and the need for implant removal following fracture healing. This international AO Spine expert survey (Level IV study) evaluated the current trends, and practice preferences among experienced surgeons in the management of UCS fractures. A structured questionnaire was answered by AO Spine Knowledge Forum Trauma and Infection (KF T I) members (n = 24). The survey collected data regarding demographics, classification use, fixation vs. fusion preferences, and implant removal practices for UCS fractures (C1, C2 odontoid, and Hangman’s fractures). Descriptive statistics were analysed. Majority were from North America and Europe (54
