A Multi-Sector Planning Support Model for en Route Air Traffic Control

RÉSUMÉ : Le concept de planification multisectorielle (PM) a été récemment introduit dans le contrôle du trafic aérien. Ce concept consiste à remplacer le contrôleur de planification par un planificateur multisectoriel (PrM). Le PrM est responsable des tâches de planification dans un ensemble de secteurs adjacents. L’objectif principal du PrM est de minimiser et d’équilibrer la charge de travail des contrôleurs entre les secteurs. Le PrM a besoin d’outils d’aide à la décision pour l’aider à accomplir ses tâches. L’objectif de cette thèse est de fournir au PrM un modèle d’aide à la décision qui minimise et équilibre la charge de travail des contrôleurs dans un ensemble de secteurs en route sur un horizon de temps moyen, soit 20 à 90 minutes. On propose une définition complète du problème de la résolution de la complexité, qui est une mesure de la charge de travail, dans le contexte de la PM. On représente la charge de travail des contrôleurs par le nombre de conflits. Pour obtenir des solutions optimales rapidement pour des problèmes impliquant de nombreux avions (par exemple 200), nous avons choisi d’utiliser un modèle de programmation linéaire mixte. Notre modèle minimise et équilibre le nombre des conflits de croisement et de rattrapage avec le nombre minimum de trajectoires modifiées. Nous présentons une formulation linéaire pour la détection et la résolution des conflits de croisement et de rattrapage. Notre formulation repose sur une transformation des distances de séparation en temps de séparation, et consiste à examiner ces temps en utilisant des contraintes linéaires. Nous avons aussi proposé une première méthode permettant d’équilibrer le nombre de conflits entre les secteurs. Notre modèle permet l’utilisation de changements de vitesse, de cap et d’altitude. Nous avons formulé le modèle de telle sorte que toutes les combinaisons de ces trois manœuvres puissent être utilisées ou empêchées. Nous avons défini les trois manœuvres pour obtenir des changements minimes du temps de parcours des trajectoires modifiées. Notre modèle ne modifie pas les points d’arrivée et de sortie des avions dans les secteurs. Pour un ensemble de problèmes étalons de détection-résolution de conflits, notre modèle a éliminé 100% des conflits dans des problèmes impliquant 25 avions et 300 conflits simultanés. Ces résultats ont été obtenus en moins d’une seconde de calculs. Pour un ensemble de problèmes de résolution de complexité générés aléatoirement et impliquant jusqu’à 200 avions, notre modèle a éliminé tous les conflits en modifiant moins de 30% des trajectoires. Le retard moyen par trajectoire modifiée était inférieur à 2,5% du temps de parcours. Nous concluons que notre modèle est un outil efficace pour réduire le nombre de conflits dans un ensemble de secteurs adjacents tout en minimisant le nombre de trajectoires modifiées. Notre modèle permet de calculer des solutions avec le nombre minimum de conflits dans un temps raisonnable (<10 minutes). Nous avons montré que l’ajout des changements de cap et d’altitude aux changements de vitesse permet de réduire significativement le nombre de conflits non résolus et le nombre de trajectoires modifiées. Nous avons aussi montré que notre méthode d’équilibrage des conflits entre les secteurs permet d’éviter de surcharger l’un des secteurs sans augmenter significativement le nombre total de conflits.----------ABSTRACT : The concept of multi-sector planning (MSP) was recently introduced into air traffic control to accommodate the continuous growth of air traffic. This concept consists in replacing the planner controller by a multi-sector planner (MSPr). The MSPr is responsible for the planning tasks in a set of adjacent sectors. The primary aim of the MSPr is to minimize and balance the workload among sectors. The MSPr needs advisory tools and models to help him fulfil his tasks. The main objective of this thesis is to develop a MSP support model that minimizes and balances controllers workload in a set of adjacent en route sectors over a medium time horizon, i.e. 20 to 90 minutes. We introduce a complete definition of the complexity resolution problem in a MSP context. The complexity is a measure for controllers workload. We choose to measure the controllers workload by the number of conflicts. Since the MSPr deals with many aircraft and requires relatively fast solutions, we formulate our model using a mixed integer linear program. Our model minimizes and balances the crossing and trailing conflicts with the minimum number of modified trajectories. We introduce a linear formulation for the detection and resolution of crossing and trailing conflicts. Our formulation relies on the transformation of safe separation distances into safe separation times and on the examination of the separation times between aircraft using linear constraints. We also propose a first method to take into account workload balancing in the complexity resolution problem. Our model enables the use of speed, heading and altitude changes. We formulated the model so that any combination of these three manoeuvres can be used or prevented. We defined the three manoeuvres so that the model ensures minimal changes in the travel duration of the modified trajectories. Our model also ensures spatial trajectory recovery. For a set of conflict detection and resolution benchmark problems, our model eliminates 100% of the conflicts in problems that involve up to 25 aircraft and 300 simultaneous conflicts. The solutions are obtained in less than one second. For a set of randomly generated complexity resolution problems, our model eliminates all the conflicts in problems that involve up to 200 aircraft by modifying less than 30% of the trajectories. The average delay per modified trajectory is less than 2.5% of the travel duration through the multi-sector area. We conclude that our model is an efficient tool to decrease and balance the total number of conflicts in a set of adjacent sectors using the minimum number of modified trajectories. Our model is able to obtain solutions with the minimum number of conflicts in a reasonable amount of time (<10 minutes). In comparison with the use of only speed changes, the introduction of the heading and altitude changes can reduce significantly the number of unresolved conflicts and the number of modified trajectories. We also found that our workload balancing method prevents overloading one of the sectors without a significant increase of the total number of conflicts

Solving Competitive Traveling Salesman Problem Using Gray Wolf Optimization Algorithm

In this paper a Gray Wolf Optimization (GWO) algorithm is presented to solve the Competitive Traveling Salesman Problem (CTSP). In CTSP, there are numbers of non-cooperative salesmen their goal is visiting a larger possible number of cities with lowest cost and most gained benefit. Each salesman will get a benefit when he visits unvisited city before all other salesmen. Two approaches have been used in this paper, the first one called static approach, it is mean evenly divides the cities among salesmen. The second approach is called parallel at which all cities are available to all salesmen and each salesman tries to visit as much as possible of the unvisited cities. The algorithms are executed for 1000 times and the results prove that the GWO is very efficient giving an indication of the superiority of GWO in solving CTSP

Decline in subarachnoid haemorrhage volumes associated with the first wave of the COVID-19 pandemic

Background During the COVID-19 pandemic, decreased volumes of stroke admissions and mechanical thrombectomy were reported. The study’s objective was to examine whether subarachnoid haemorrhage (SAH) hospitalisations and ruptured aneurysm coiling interventions demonstrated similar declines. Methods We conducted a cross-sectional, retrospective, observational study across 6 continents, 37 countries and 140 comprehensive stroke centres. Patients with the diagnosis of SAH, aneurysmal SAH, ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases, 10th Revision, codes. The 3-month cumulative volume, monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before (1 year and immediately before) and during the pandemic, defined as 1 March–31 May 2020. The prior 1-year control period (1 March–31 May 2019) was obtained to account for seasonal variation. FindingsThere was a significant decline in SAH hospitalisations, with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic, representing a relative decline of 22.5% (95% CI −24.3% to −20.7%, p Interpretation There was a relative decrease in the volume of SAH hospitalisations, aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 pandemic. These findings in SAH are consistent with a decrease in other emergencies, such as stroke and myocardial infarction

Craniofacial anthropometric measurements of the cohort of Egyptian male school children and their utility in detection of abnormalities

ABSTRACT: Background Anthropology is a scientific discipline which applies scientific methods to identify and quantitate inter-individual variations in body structure and function. Anthropometry assesses craniofacial dysmorphology in genetic disorders and helps to detect phenotypic differences in diseases with common underlying cause. This study is part of a comprehensive cross-sectional study of craniofacial and oral findings in Egyptian school children. This paper focused on establishing the norms of Egyptian male school children and its utility in determining the differences in facial measurements of a child with Prader–Willi syndrome (PWS). Thirty craniofacial measurements were taken from 55 healthy Egyptian school children aged 12–14 years with mean age 13 ± 0.64 and a PWS child aged 13.6 years. The PWS measurements were compared with healthy children of the same age using computed Z-score. Results Morphological face height of the PWS child was within the normal range. However, upper face height and nose height were significantly lower with Z-scores of - 3.18 and - 2.7, respectively; right and left mandibular body length and upper lip height were significantly higher than the mean of healthy children with corresponding Z-scores of 2.95, 2.48, and 2.33. Conclusions By establishing the norms of Egyptian male school children and utilizing these data, we can identify the difference in facial measurements among children with abnormalities like PWS. This information can be used during periodic checkups as a simple, non-invasive, and economical method for the detection of these abnormalities

Double-blind randomized proof-of-concept trial of canakinumab in patients with COVID-19 associated cardiac injury and heightened inflammation

AIMS: In coronavirus disease 2019 (COVID-19), myocardial injury is associated with systemic inflammation and higher mortality. Our aim was to perform a proof of concept trial with canakinumab, a monoclonal antibody to interleukin-1β, in patients with COVID-19, myocardial injury, and heightened inflammation. METHODS AND RESULTS: This trial required hospitalization due to COVID-19, elevated troponin, and a C-reactive protein concentration more than 50 mg/L. The primary endpoint was time to clinical improvement at Day 14, defined as either an improvement of two points on a seven-category ordinal scale or discharge from the hospital. The secondary endpoint was mortality at Day 28. Forty-five patients were randomly assigned to canakinumab 600 mg ( CONCLUSION: There was no difference in time to clinical improvement at Day 14 in patients treated with canakinumab, and no safety concerns were identified. Future studies could focus on high dose canakinumab in the treatment arm and assess efficacy outcomes at Day 28

Pulmonary embolism versus pulmonary vasculitis in Hughes-Stovin syndrome: Characteristic computed tomography pulmonary angiographic findings and diagnostic and therapeutic implications. HSS International Study Group

Background and aim: Hughes-Stovin syndrome (HSS) is a rare systemic vasculitis with widespread venous/arterial thrombosis and pulmonary vasculitis. Distinguishing between pulmonary embolism (PE) and in-situ thrombosis in the early stages of HSS is challenging. The aim of the study is to compare clinical, laboratory, and computed tomography pulmonary angiography (CTPA) characteristics in patients diagnosed with PE versus those with HSS. Methods: This retrospective study included 40 HSS patients with complete CTPA studies available, previously published by the HSS study group, and 50 patients diagnosed with PE from a single center. Demographics, clinical and laboratory findings, vascular thrombotic events, were compared between both groups. The CTPA findings were reviewed, with emphasis on the distribution, adherence to the mural wall, pulmonary infarction, ground glass opacification, and intra-alveolar hemorrhage. Pulmonary artery aneurysms (PAAs) in HSS were assessed and classified. Results: The mean age of HSS patients was 35 ± 12.3 years, in PE 58.4 ± 17 (p &lt; 0.0001). Among PE 39(78 %) had co-morbidities, among HSS none. In contrast to PE, in HSS both major venous and arterial thrombotic events are seen. Various patterns of PAAs were observed in the HSS group, which were entirely absent in PE. Parenchymal hemorrhage was also more frequent in HSS compared to PE (P &lt; 0.001). Conclusion: Major vascular thrombosis with arterial aneurysms formation are characteristic of HSS. PE typically appear loosely-adherent and mobile whereas “in-situ thrombosis” seen in HSS is tightly-adherent to the mural wall. Mural wall enhancement and PAAs are distinctive pulmonary findings in HSS. The latter findings have significant therapeutic ramifications.</p

Cerebrovascular events and outcomes in hospitalized patients with COVID-19: The SVIN COVID-19 Multinational Registry

© 2020 World Stroke Organization.[Background]: Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has been associated with a significant risk of thrombotic events in critically ill patients. [Aim]: To summarize the findings of a multinational observational cohort of patients with SARS-CoV-2 and cerebrovascular disease. [Methods]: Retrospective observational cohort of consecutive adults evaluated in the emergency department and/or admitted with coronavirus disease 2019 (COVID-19) across 31 hospitals in four countries (1 February 2020–16 June 2020). The primary outcome was the incidence rate of cerebrovascular events, inclusive of acute ischemic stroke, intracranial hemorrhages (ICH), and cortical vein and/or sinus thrombosis (CVST). [Results]: Of the 14,483 patients with laboratory-confirmed SARS-CoV-2, 172 were diagnosed with an acute cerebrovascular event (1.13% of cohort; 1130/100,000 patients, 95%CI 970–1320/100,000), 68/171 (40.5%) were female and 96/172 (55.8%) were between the ages 60 and 79 years. Of these, 156 had acute ischemic stroke (1.08%; 1080/100,000 95%CI 920–1260/100,000), 28 ICH (0.19%; 190/100,000 95%CI 130–280/100,000), and 3 with CVST (0.02%; 20/100,000, 95%CI 4–60/100,000). The in-hospital mortality rate for SARS-CoV-2-associated stroke was 38.1% and for ICH 58.3%. After adjusting for clustering by site and age, baseline stroke severity, and all predictors of in-hospital mortality found in univariate regression (p < 0.1: male sex, tobacco use, arrival by emergency medical services, lower platelet and lymphocyte counts, and intracranial occlusion), cryptogenic stroke mechanism (aOR 5.01, 95%CI 1.63–15.44, p < 0.01), older age (aOR 1.78, 95%CI 1.07–2.94, p ¼ 0.03), and lower lymphocyte count on admission (aOR 0.58, 95%CI 0.34–0.98, p ¼ 0.04) were the only independent predictors of mortality among patients with stroke and COVID-19. [Conclusions]: COVID-19 is associated with a small but significant risk of clinically relevant cerebrovascular events, particularly ischemic stroke. The mortality rate is high for COVID-19-associated cerebrovascular complications; therefore, aggressive monitoring and early intervention should be pursued to mitigate poor outcomes

Decline in subarachnoid haemorrhage volumes associated with the first wave of the COVID-19 pandemic

BACKGROUND: During the COVID-19 pandemic, decreased volumes of stroke admissions and mechanical thrombectomy were reported. The study\u27s objective was to examine whether subarachnoid haemorrhage (SAH) hospitalisations and ruptured aneurysm coiling interventions demonstrated similar declines. METHODS: We conducted a cross-sectional, retrospective, observational study across 6 continents, 37 countries and 140 comprehensive stroke centres. Patients with the diagnosis of SAH, aneurysmal SAH, ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases, 10th Revision, codes. The 3-month cumulative volume, monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before (1 year and immediately before) and during the pandemic, defined as 1 March-31 May 2020. The prior 1-year control period (1 March-31 May 2019) was obtained to account for seasonal variation. FINDINGS: There was a significant decline in SAH hospitalisations, with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic, representing a relative decline of 22.5% (95% CI -24.3% to -20.7%, p\u3c0.0001). Embolisation of ruptured aneurysms declined with 1170-1035 procedures, respectively, representing an 11.5% (95%CI -13.5% to -9.8%, p=0.002) relative drop. Subgroup analysis was noted for aneurysmal SAH hospitalisation decline from 834 to 626 hospitalisations, a 24.9% relative decline (95% CI -28.0% to -22.1%, p\u3c0.0001). A relative increase in ruptured aneurysm coiling was noted in low coiling volume hospitals of 41.1% (95% CI 32.3% to 50.6%, p=0.008) despite a decrease in SAH admissions in this tertile. INTERPRETATION: There was a relative decrease in the volume of SAH hospitalisations, aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 pandemic. These findings in SAH are consistent with a decrease in other emergencies, such as stroke and myocardial infarction

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030