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Global pandemics may limit access to specialized care, delaying diagnosis and treatment of common acute surgical diseases. We analyzed the impact of the novel coronavirus disease 2019 (COVID-19) pandemic on acute appendicitis at an urban tertiary care center. We hypothesize that pandemics are associated with delayed presentation and worsened clinical sequelae, specifically, higher incidences of perforation in children. We retrospectively assessed patients admitted to our institution with acute appendicitis in pre-pandemic control (February 2018–June 2019) and COVID-19 (February 2020–June 2021) cohorts. Primary outcomes included complicated appendicitis rates (perforation/abscess/bowel obstruction), COVID-19 status, complications and travel distance to our institution. 1107 patients met inclusion criteria: 491 (44.4%) during the control period and 616 (55.6%) in the COVID-19 cohort. Statistical analysis involved t-tests, contingency tables and logistic regression modelling for key variables. A larger proportion of complicated appendicitis occurred during COVID-19 compared to controls (28.3% vs 38.8%, p < 0.001). Symptom duration at presentation and length of stay were not significantly different. Duration of antibiotic treatment, surgery length, readmission rate and travel distances were significantly higher during COVID-19. The pre-pandemic cohort had a significantly younger age distribution. Pediatric appendicitis was significantly impacted during COVID-19, demonstrated by increased rates of complicated appendicitis, surgery duration and antibiotic duration. This may be an unintended secondary consequence of patients avoiding healthcare facilities for non-pandemic related illnesses or lockdown policies. Government policies directing all provincial pediatric appendicitis cases to pediatric institutions increased travel distances for our patients and had unanticipated consequences and resource requirements on tertiary healthcare. Level III for "Treatment Studies". • The COVID-19 pandemic caused hospitals to alter protocols to reserve resources for COVID-19-positive patients. • Hospital protocol changes impacted all aspects of healthcare and potentially, access to time-sensitive interventions. • Our data highlights unanticipated consequences of pandemic related policies such as increase in complicated appendicitis. [ABSTRACT FROM AUTHOR]

Developments in the railway industry are continuously evolving and long-term transition strategies can enable an efficient implementation of signalling technologies that provide a significant increase in network capacity and operation efficiency. Virtual Coupling (VC) advances moving block signalling by further reducing train separation to less than an absolute braking distance using train-to-train communication and cooperative train control within a Virtually-Coupled Train Set (VCTS). This paper proposes a method to develop scenario-based roadmaps based on a SWOT and hybrid Delphi-AHP multi-criteria analysis. Step-changes are identified and initially assessed in a Swimlane based on priorities and time order collected from stakeholders through a survey and further developed in a workshop. Optimistic and pessimistic scenarios are assessed regarding various factors and timelines. Step-changes are initially defined in a Swimlane and then enriched with optimistic and pessimistic scenarios to ultimately derive scenario-based roadmaps. Durations for each of the step-changes are developed into scenario-based roadmaps that can be used as an efficient tool for stakeholders to identify and solve potential criticalities/risks to the deployment of VC as well as to setup investment and development plans. The approach is applied to deliver implementation roadmaps of VC for different market segments with particular focus on mainline railways. • A gap analysis identifies step-changes to deploy Virtual Coupling (VC) in Europe. • A framework is proposed to generate scenario-based roadmaps for rail technology. • Scenario-based roadmaps of VC are identified for different rail markets. • Most markets could deploy VC by 2050, but main-lines showing higher complexity. • Produced roadmaps can support stakeholders in setting policies and strategic plans. [ABSTRACT FROM AUTHOR]

Automatic Train Operation (ATO) is well-known in urban railways and gets increasing interest from mainline railways at present to improve capacity and punctuality. A main function of ATO is the train trajectory generation that specifies the speed profile over the given running route considering the timetable and the characteristics of the train and infrastructure. This paper proposes and assesses different possible ATO architecture configurations through allocating the intelligent components on the trackside or onboard. The set of analyzed ATO architecture configurations is based on state-of-the-art architectures proposed in the literature for the related Connected Driver Advisory System (C-DAS). Results of the SWOT analysis highlight that different ATO configurations have diverse advantages or limitations, depending on the type of railway governance and the technological development of the existing railway signaling and communication equipment. In addition, we also use the results to spotlight operational, technological, and business advantages/limitations of the proposed ATO-over-ETCS architecture that is being developed by the European Union Agency for Railways (ERA) and provide a scientific argumentation for it. • An analysis of essential driving function differences between C-DAS and ATO. • A proposal of three different ATO system architecture configurations. • A SWOT analysis of the ATO architecture alternatives for different railway markets. • Scientific argumentation for the ATO-over-ETCS reference architecture. [ABSTRACT FROM AUTHOR]

This paper analyzes the effectiveness of decentralized strategies for dispatching rolling stock and train drivers in a railway system. Such strategies give operators a robust alternative in case centralized control fails due to an abundance of infrastructure or rolling stock disruptions or information system malfunctions. We test the performance of four rolling stock and two driver dispatching strategies in a microscopic simulation. Our test case is a part of the Dutch railway network, containing eleven stations linked by four train lines. We find that with the decentralized dispatching strategies, target frequencies of the lines are approximately met and train services are highly regular without large delays. Especially strategies that allow rolling stock to switch between lines result in a high performance. [ABSTRACT FROM AUTHOR]

To address the ever-growing rail transport demand, the concept of Virtual Coupling train operations is gradually gaining ground within the railway industry. Thanks to a Vehicle-to-Vehicle communication, trains could be separated by less than an absolute braking distance and even form connected platoons to increase capacity at bottlenecks. However, a major concern about this concept regards the risk of safety violations in case of operational hazards pertaining to delays in train communication and control or emergency train stops. In this paper, the notion of dynamic safety margin is introduced for Virtual Coupling to dynamically adjust train separations so to always keep required safety distances also when hazardous operational events occur. The dynamic safety margin is embedded in a multi-state train-following model to analyse Virtual Coupling operations in presence of operational risk factors. A three-step methodology is applied in a real case study to fine-tune and verify the model, perform a sensitivity analysis, and identify capacity gains in several test scenarios including nominal and degraded traffic conditions. Results show that the use of a dynamic safety margin provides substantial capacity benefits to Virtual Coupling while respecting safe train distances even in case of sudden failures of the train control or communication systems. The notion of a dynamic safety margin can hence contribute to a safer version of Virtual Coupling operations and be considered by the railway industry in defining system requirements. • A dynamic safety margin is proposed to mitigate safety risks of Virtual Coupling. • A train-following model is used to assess impacts on railway capacity. • Virtual Coupling is compared to Moving Block for different operational scenarios. • A dynamic margin shows to keep VC operations safe even in presence of risk factors. • VC with a dynamic margin outperforms MB capacity even for heterogeneous traffic. [ABSTRACT FROM AUTHOR]

Highlights: [•] Stability of railway rescheduling plans is analysed under a stochastic environment. [•] A dispatching tool is integrated in a closed-loop with a railway traffic simulator. [•] Rescheduling plans become unstable when disturbances start propagating. [•] Train reordering varies more when enlarging the length of the prediction horizon. [•] Longer prediction horizons lead to solutions that prefer reordering to retiming. [Copyright &y& Elsevier]

Highlights: [•] Train running time parameters calibrated against real track occupation data. [•] A simulation-based optimization is used to derive dynamic speed profiles. [•] Some parameters of tractive effort and resistance do not affect train behaviours. [•] Calibrated resistance parameters differ from default values. [•] Big differences between default and calibrated braking rate is observed. [Copyright &y& Elsevier]

Stomatal closure and biosynthesis of antioxidant molecules are two fundamental components of the physiological machinery that lead to stress adaptation during plant''s exposure to salinity. Since high stomatal resistance may also contribute in counteracting O3 damages, we hypothesized that soil salinization may increase O3 tolerance of crops. An experiment was performed with alfalfa grown in filtered (AOT40=0 in both years) and non-filtered (AOT40=9.7 in 2005 and 6.9ppmh in 2006) open-top chambers. Alfalfa yield was reduced by O3 (−33%) only in plants irrigated with salt-free water, while the increasing levels of soil salinity until 1.06dSm−1 reduced both stomatal conductance and plant O3 uptake, thus linearly reducing O3 effects on yield. Therefore a reliable flux-based model for assessing the effects of O3 on crop yield should take into account soil salinity. [Copyright &y& Elsevier]

Chest radiography showed bilateral multiple diffuse lung microopacities and narrowing of the proximal trachea (Fig. Neck and chest computed tomography confirmed the radiography finding (Fig. Graph: Figure 1 Chest radiography (A) and coronal computed tomography image (B) showing multiple infiltrative and confluent nodular microopacities disseminated in all lung fields. [Extracted from the article]

Abstract: We describe a case report of a 6-year-old boy with a 4-year history of recurrent vomiting with a cyclical vomiting pattern. Although initially labelled with and treated for Cyclical Vomiting Syndrome the cause was subsequently found to be an enteric duplication associated with cystic lymphangioma, an association not previously described. [Copyright &y& Elsevier]