Volume of the polar of random sets and shadow systems

We obtain optimal inequalities for the volume of the polar of random sets, generated for instance by the convex hull of independent random vectors in Euclidean space. Extremizers are given by random vectors uniformly distributed in Euclidean balls. This provides a random extension of the Blaschke-Santalo inequality which, in turn, can be derived by the law of large numbers. The method involves generalized shadow systems, their connection to Busemann type inequalities, and how they interact with functional rearrangement inequalities

A critical review on the vulnerability assessment of natural gas pipelines subjected to seismic wave propagation. Part 1:Fragility relations and implemented seismic intensity measures

© 2019 Elsevier Ltd Natural gas (NG) pipeline networks constitute a critical means of energy transportation, playing a vital role in the economic development of modern societies. The associated socio-economic and environmental impact, in case of seismically-induced severe damage, highlights the importance of a rational assessment of the structural integrity of this infrastructure against seismic hazards. Up to date, this assessment is mainly performed by implementing empirical fragility relations, which associate the repair rate, i.e. the number of repairs/damages per unit length of the pipeline, with a seismic intensity measure. A limited number of analytical fragility curves that compute probabilities of failure for various levels of predefined damage states have also been proposed, recently. In the first part of this paper, a thorough critical review of available fragility relations for the vulnerability assessment of buried NG pipelines is presented. The paper focuses on the assessment against seismically-induced transient ground deformations, which, under certain circumstances, may induce non-negligible deformations and strains on buried NG pipelines, especially in cases of pipelines crossing heterogeneous soil sites. Particular emphasis is placed on the efficiency of implemented seismic intensity measures to be evaluated or measured in the field and, more importantly, to correlate with observed structural damage on buried NG pipelines. In the second part of this paper, alternative methods for the analytical evaluation of the fragility of steel NG pipelines under seismically-induced transient ground deformations are presented. Through the discussion, recent advancements in the field are highlighted, whilst acknowledged gaps are identified, providing recommendations for future research

On The Numerical Simulation of The Response of Gas Pipelines Under Compression

Steel gas pipelines may be subjected to buckling failure under large compressive straining, caused by seismically induced ground deformations. This paper further elaborates on the buckling response of this type of networks, through the presentation of representative results from a series of axial compression static analyses that were conducted on segments of steel gas pipelines. Above ground and embedded segments of diverse radius to thickness ratios (R/t) were simulated by means of inelastic shell elements. The trench of embedded pipelines was modelled using solid elastic elements, while an advanced contact model was used to simulate the pipe-soil interface. Salient parameters that affect the axial response, including the internal pressure and the existence of imperfections on the segment, were considered in this study. In line with previous evidence, the results reveal a reduction of the axial response of the pipe segment with increasing levels of internal pressure. In parallel, internal pressure leads the limit stresses to occur at progressively higher axial deformations, while limit loads computed for embedded pipelines are higher compared to those predicted for equivalent above ground pipelines, as a result of the soil confinement

Impact of safety-related dose reductions or discontinuations on sustained virologic response in HCV-infected patients: Results from the GUARD-C Cohort

BACKGROUND: Despite the introduction of direct-acting antiviral agents for chronic hepatitis C virus (HCV) infection, peginterferon alfa/ribavirin remains relevant in many resource-constrained settings. The non-randomized GUARD-C cohort investigated baseline predictors of safety-related dose reductions or discontinuations (sr-RD) and their impact on sustained virologic response (SVR) in patients receiving peginterferon alfa/ribavirin in routine practice. METHODS: A total of 3181 HCV-mono-infected treatment-naive patients were assigned to 24 or 48 weeks of peginterferon alfa/ribavirin by their physician. Patients were categorized by time-to-first sr-RD (Week 4/12). Detailed analyses of the impact of sr-RD on SVR24 (HCV RNA <50 IU/mL) were conducted in 951 Caucasian, noncirrhotic genotype (G)1 patients assigned to peginterferon alfa-2a/ribavirin for 48 weeks. The probability of SVR24 was identified by a baseline scoring system (range: 0-9 points) on which scores of 5 to 9 and <5 represent high and low probability of SVR24, respectively. RESULTS: SVR24 rates were 46.1% (754/1634), 77.1% (279/362), 68.0% (514/756), and 51.3% (203/396), respectively, in G1, 2, 3, and 4 patients. Overall, 16.9% and 21.8% patients experienced 651 sr-RD for peginterferon alfa and ribavirin, respectively. Among Caucasian noncirrhotic G1 patients: female sex, lower body mass index, pre-existing cardiovascular/pulmonary disease, and low hematological indices were prognostic factors of sr-RD; SVR24 was lower in patients with 651 vs. no sr-RD by Week 4 (37.9% vs. 54.4%; P = 0.0046) and Week 12 (41.7% vs. 55.3%; P = 0.0016); sr-RD by Week 4/12 significantly reduced SVR24 in patients with scores <5 but not 655. CONCLUSIONS: In conclusion, sr-RD to peginterferon alfa-2a/ribavirin significantly impacts on SVR24 rates in treatment-naive G1 noncirrhotic Caucasian patients. Baseline characteristics can help select patients with a high probability of SVR24 and a low probability of sr-RD with peginterferon alfa-2a/ribavirin

The challenges of a randomised placebo-controlled trial of CTO PCI vs. placebo with optimal medical therapy: The ORBITA-CTO pilot study design and protocol

BackgroundPercutaneous coronary intervention (PCI) for coronary chronic total occlusion (CTO) has been performed for the improvement of symptoms and quality of life in patients with stable angina. The ORBITA study demonstrated the role of the placebo effect in contemporary PCI in non-CTO chronic coronary syndromes. However, the benefit of CTO PCI beyond that of a placebo has not been demonstrated.AimsThe ORBITA-CTO pilot study will be a double-blind, placebo-controlled study of CTO PCI randomising patients who have: (1) been accepted by a CTO operator for PCI; (2) experienced symptoms due to a CTO; (3) evidence of ischaemia; (4) evidence of viability within the CTO territory; and (5) a J-CTO score ≤3.MethodsPatients will undergo medication optimisation that will ensure they are on at least a minimum amount of anti-anginals and complete questionnaires. Patients will record their symptoms on an app daily throughout the study. Patients will undergo randomisation procedures, including an overnight stay, and be discharged the following day. All anti-anginals will be stopped after randomisation and re-initiated on a patient-led basis during the 6-month follow-up period. At follow-up, patients will undergo repeat questionnaires and unblinding, with a further 2-week unblinded follow-up.ResultsThe co-primary outcomes are feasibility (blinding) in this cohort and angina symptom score using an ordinal clinical outcome scale for angina. Secondary outcomes include changes in quality-of-life measures, Seattle Angina Questionnaire (SAQ), peak VO2, and anaerobic threshold on the cardiopulmonary exercise test.ConclusionThe feasibility of a placebo-controlled CTO PCI study will lead to future studies assessing efficacy. The impact of CTO PCI on angina measured using a novel daily symptom app may provide improved fidelity in assessing symptoms in patients with CTO's