Les pratiques de marché en éducation et la cohésion scolaire au Québec

Au cours des dernières décennies, l'évolution du système éducatif québécois a été caractérisée par des logiques du marché. En accordant aux parents la liberté de choisir l’école pour leurs enfants et à l’établissement la possibilité de sélectionner ses élèves, les pouvoirs politiques ont ouvert la porte à la compétition intra et inter établissements (Kamanzi, 2018, 2019). Cette dynamique du marché accentue, entre autres, des inégalités scolaires et sociales où les élèves sont séparés selon leurs capacités et, de façon implicite, leur origine sociale (Desjardins, Lessard et Blais, 2011; Marcotte-Fournier, 2015; Marcotte-Fournier et al., 2016; Larose, 2016, Hurteau et Duclos, 2017). À partir des données de l’enquête Pisa 2015, nous étudions les effets des pratiques de marché sur la cohésion scolaire. Celle-ci est analysée à travers les sentiments d’appartenance, de confiance et de coopération chez les élèves du secondaire. Les analyses montrent que la stratification scolaire et la présence de compétition sont liées à la cohésion scolaire. D'une part, les élèves des écoles privées sont ceux qui maintiennent une forte cohésion dans leur environnement scolaire. D'autre part, plus il y a de concurrence au sein de l’établissement, plus le sentiment d'appartenance est élevé. À partir de ces constats, l’étude suggère quelques pistes d’interprétation pour mieux comprendre la nature de la compétition, mais aussi envisager les moyens d'établir une cohabitation saine entre la cohésion et les logiques du marché scolaire dans le contexte du système scolaire québécois.Over the past few decades, market forces have characterized the evolution of Quebec’s education system. By giving parents the freedom to choose the school that their children attend and schools the opportunity to select their students, political leaders have opened the door to intra- and inter-school competition (Kamanzi, 2018, 2019). This results, among other things, in educational and social inequalities where students are separated according to their abilities and, implicitly, their social background (Desjardins, Lessard and Blais, 2011; Marcotte-Fournier, 2015; Marcotte-Fournier et al., 2016; Larose, 2016, Hurteau and Duclos, 2017). Using data from the Pisa 2015 survey, we study the effects of market practices on school cohesion. We analyze this phenomenon through the feelings of belonging, trust and cooperation among secondary school students. Our analyses show that school stratification and the presence of competition are linked to school cohesion. On the one hand, students in private schools are those who maintain a strong cohesion in their school environment. On the other hand, the more competition there is within the institution, the higher the sense of belonging. Based on these findings, the study suggests some possible interpretations to better understand the nature of competition, but also to consider ways to establish a healthy cohabitation between cohesion and the logic of school markets in the context of Quebec’s school system

Conception et mise en oeuvre d'une tête de réception à échantillonnage direct RF pour les signaux de radionavigation par satellites

Dans la prochaine décennie, la navigation par satellites connaîtra un essor fulgurant avec l’arrivée des européens et des chinois, qui entreront en compétition avec les systèmes de positionnement américain et russe existants. Les récepteurs GNSS devront dès lors s’adapter à une multitude de signaux situés à des fréquences différentes. Pour ce faire, la technique classique consiste en l’ajout d’une tête de réception pour chaque signal GNSS à capturer. Toutefois, cette approche devient rapidement complexe et coûteuse pour un récepteur multifréquences. Pour pallier ces problèmes, une approche nouvelle et élégante est d’échantillonner tous les signaux simultanément et de les traiter numériquement par la suite. Cette technique est connue sous le nom d’échantillonnage direct RF. Ce mémoire vise la mise en oeuvre en temps réel ainsi que l’évaluation des performances d’une tête de réception à échantillonnage direct RF pour les signaux de radionavigation par satellites. Pour ce faire une chaîne de traitement du signal RF et numérique est conçue en tenant compte de différentes contraintes, notamment au niveau de la gigue de phase. L’étude théorique prédit qu’elle ne doit pas dépasser 1.159 ps pour que son effet soit négligeable pour un récepteur GNSS. Le prototype réalisé se concentre sur le signal GPS L1 C/A tout en conservant le maximum de flexibilité pour les travaux ultérieurs sur toute la bande GNSS. La chaîne de traitement du signal RF conçue permet une amplification d’environ 100 dB de toute la bande GNSS et possède une figure de bruit de 1.52 dB. Pour le prototype de tête de réception du signal GPS L1 C/A, des filtres RF limitent la capture du signal à une bande d’environ 25 MHz autour de la fréquence L1. Le convertisseur analogique-numérique AT84AS004 de la compagnie Atmel est utilisé et est configuré pour échantillonner les signaux sur 7 bits à une cadence de 300 MHz. Ces derniers sont transmis à un FPGA de type Virtex-4 FX12 qui effectue le traitement du signal numérique. La chaîne de traitement dans le FPGA est composée d’une conversion numérique en fréquence polyphase ainsi que d’une décimation polyphase de facteur 5 utilisant un filtre FIR du 50e ordre. La tête de réception conçue est par la suite connectée au récepteur RxGNSS conçu au LACIME. Les performances de cette tête de réception sont similaire, voire meilleures, à celles de la tête de réception superhétérodyne classique du RxGNSS. En effet, on note une diminution d’environ 20% du bruit sur l’erreur résiduelle de la pseudo-distance et de la phase de la porteuse GPS L1 C/A. Les mesures de l’effet de la gigue de phase sur la tête de réception conçue montrent que cette gigue n’a aucun effet sur les performances du RxGNSS à condition qu’elle soit inférieure à environ 5 ps. Une gigue de phase supérieure cause une diminution du C/N0, ce qui entraîne une augmentation du bruit sur les mesures de pseudo-distance et ainsi qu’une perte de sensibilité et de précision du récepteur

Location Management in IP-based Future LEO Satellite Networks: A Review

Future integrated terrestrial, aerial, and space networks will involve thousands of Low Earth Orbit (LEO) satellites forming a network of mega-constellations, which will play a significant role in providing communication and Internet services everywhere, at any time, and for everything. Due to its very large scale and highly dynamic nature, future LEO satellite networks (SatNets) management is a very complicated and crucial process, especially the mobility management aspect and its two components location management and handover management. In this article, we present a comprehensive and critical review of the state-of-the-art research in LEO SatNets location management. First, we give an overview of the Internet Engineering Task Force (IETF) mobility management standards (e.g., Mobile IPv6 and Proxy Mobile IPv6) and discuss their location management techniques limitations in the environment of future LEO SatNets. We highlight future LEO SatNets mobility characteristics and their challenging features and describe two unprecedented future location management scenarios. A taxonomy of the available location management solutions for LEO SatNets is presented, where the solutions are classified into three approaches. The "Issues to consider" section draws attention to critical points related to each of the reviewed approaches that should be considered in future LEO SatNets location management. To identify the gaps, the current state of LEO SatNets location management is summarized. Noteworthy future research directions are recommended. This article is providing a road map for researchers and industry to shape the future of LEO SatNets location management.Comment: Submitted to the Proceedings of the IEE

Site Diversity in Downlink Optical Satellite Networks Through Ground Station Selection

Recent advances have shown that satellite communication (SatCom) will be an important enabler for next generation terrestrial networks as it can provide numerous advantages, including global coverage, high speed connectivity, reliability, and instant deployment. An ideal alternative for radio frequency (RF) satellites is its free-space optical (FSO) counterpart. FSO or laser SatCom can mitigate the problems occurring in RF SatCom, while providing important advantages, including reduced mass, lower consumption, better throughput, and lower costs. Furthermore, laser SatCom is inherently resistant to jamming, interception, and interference. Owing to these benefits, this paper focuses on downlink laser SatCom, where the best ground station (GS) is selected among numerous candidates to provide reliable connectivity and maximum site diversity. To quantify the performance of the proposed scheme, we derive closed-form outage probability and ergodic capacity expressions for two different practical GS deployment scenarios. Furthermore, asymptotic analysis is conducted to obtain the overall site diversity gain, and aperture averaging is studied to illustrate the impact of aperture diameter on the overall performance. Finally, important design guidelines that can be useful in the design of practical laser SatComs are outlined

Routing Heterogeneous Traffic in Delay-Tolerant Satellite Networks

Delay-tolerant networking (DTN) offers a novel architecture that can be used to enhance store-carry-forward routing in satellite networks. Since these networks can take advantage of scheduled contact plans, distributed algorithms like the Contact Graph Routing (CGR) can be utilized to optimize data delivery performance. However, despite the numerous improvements made to CGR, there is a lack of proposals to prioritize traffic with distinct quality of service (QoS) requirements. This study presents adaptations to CGR to improve QoS-compliant delivery ratio when transmitting traffic with different latency constraints, along with an integer linear programming optimization model that serves as a performance upper bound. The extensive results obtained by simulating different scenarios show that the proposed algorithms can effectively improve the delivery ratio and energy efficiency while meeting latency constraints

Anxiety following mild traumatic brain injury

Purpose/Objective: The goals of the present study were (1) to document the prevalence of anxiety-related disorders and anxiety symptoms at 4, 8, and 12 months post-injury in individuals with mild traumatic brain injury (mTBI) while considering pre-injury history of anxiety disorders and (2) to verify whether the presence of anxiety in the first months following mTBI was associated with more symptoms present one year after the injury. Research Method/Design: One hundred and twenty participants hospitalized after an accident and having sustained mTBI were assessed at 4, 8, and 12 months post-accident with the Mini-International Neuropsychiatric Interview, the Hospital Anxiety and Depression Scale and questionnaires assessing fatigue, irritability, perceived stress, cognitive difficulties, depression, insomnia, and pain. Results: At 4 months, 23.8% of participants presented with at least one anxiety-related disorder compared to 15.2% at 8 months and 11.2% at 12 months. Overall, 32.5% presented with at least one anxiety disorder over the first 12 months post-mTBI. Participants with a history of anxiety (20.5%) were significantly more anxious following their accident. Individuals who were anxious 4 months after the accident presented with more symptoms in different areas 12 months post-injury compared to non-anxious individuals. Conclusions/Implications: The present results highlight that anxiety should be evaluated and managed carefully as it appears to be a key factor in the persistence of other mTBI-related symptom

Extending our scientific reach in arboreal ecosystems for research and management

The arboreal ecosystem is vitally important to global and local biogeochemical processes, the maintenance of biodiversity in natural systems, and human health in urban environments. The ability to collect samples, observations, and data to conduct meaningful scientific research is similarly vital. The primary methods and modes of access remain limited and difficult. In an online survey, canopy researchers (n = 219) reported a range of challenges in obtaining adequate samples, including ∼10% who found it impossible to procure what they needed. Currently, these samples are collected using a combination of four primary methods: (1) sampling from the ground; (2) tree climbing; (3) constructing fixed infrastructure; and (4) using mobile aerial platforms, primarily rotorcraft drones. An important distinction between instantaneous and continuous sampling was identified, allowing more targeted engineering and development strategies. The combination of methods for sampling the arboreal ecosystem provides a range of possibilities and opportunities, particularly in the context of the rapid development of robotics and other engineering advances. In this study, we aim to identify the strategies that would provide the benefits to a broad range of scientists, arborists, and professional climbers and facilitate basic discovery and applied management. Priorities for advancing these efforts are (1) to expand participation, both geographically and professionally; (2) to define 2–3 common needs across the community; (3) to form and motivate focal teams of biologists, tree professionals, and engineers in the development of solutions to these needs; and (4) to establish multidisciplinary communication platforms to share information about innovations and opportunities for studying arboreal ecosystems

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570