The GARCH (1, 1) Model As A Risk Predictor For International Portfolios

This study pertains to forecasting portfolio risk using a GARCH (Generalized Autoregressive Conditional Heteroscedasticity) approach. Three models are compared to the GARCH model (1,1) i.e., random walk (RW), historical mean (HMM) and J.P. Morgans exponentially weighted moving average (EWMA). In recent years, many volatility forecasting models have been presented in the financial literature. Using the historical average of stock returns to determine the optimal portfolio is current practice in academic circles. However, we doubt the ability of this method to provide the best estimated portfolio variance. Moreover, an error in the estimated covariance matrix could result in a completely different portfolio mix. Consequently, we believe it would be relevant to examine the volatility forecasting model proposed in different studies to estimate the standard deviation of an efficient portfolio. With a view to building an efficient portfolio in an international context, we will analyze the forecasting models mentioned above. The purpose of this research is to determine whether a GARCH approach to forecasting the covariance matrix makes it possible to obtain a risk that most resembles the actual observed risk for a given return than the model traditionally used by practitioners and academic researchers. To this end, we selected six international stock indices. The study was conducted in a Canadian context and consequently, each stock index is converted into Canadian dollars. Initially, we estimate the covariance matrix for each forecasting model mentioned above. Then, we determine the proportions to invest in the portfolio and calculate the standard deviation of a minimum variance portfolio. Finally, the best model is selected based on the variances between estimated and actual risk by minimizing the root mean squared error (RMSE) for each forecasting model. Our results show that the GARCH (1,1) model is good for estimating risk in a minimum variance portfolio. As well, we find that it is statistically impossible to make a distinction between the accuracy of this model and the RW model. Lastly, our results show that based on the four statistical error measures used, the HMM is the least accurate for estimating portfolio risk. We therefore decided not to use this model and to rely instead on the GARCH approach or the RW, the simplest of all the models

Étude de la dynamique d'un robot sphérique et de son effet sur l'attention et la mobilité de jeunes enfants

Le présent travail porte sur l'étude d'un robot sphérique autonome nommé Roball. Un premier prototype démontrant sa faisabilité fut développé en 1999. Toutefois, pour pouvoir conduire des expériences sur un plus grand nombre d'enfants dans des conditions moins restrictives, il est primordial de concevoir et construire un nouveau prototype mieux adapté. Ainsi, la nouvelle conception de Roball amène des avantages intéressants. Entre autres, l'accès aux piles a été facilité et les paroles sont audibles clairement. Une interface a aussi été conçue. Elle prend la forme d'un visage et elle permet d'augmenter le nombre d'interactions et de faciliter la mise en marche et l'arrêt du robot. Enfin, grâce à un nouveau mécanisme, le mouvement latéral (gauche-droite) du robot possède beaucoup plus de liberté, ce qui engendre de nouvelles possibilités de positionnement. Puisque la richesse des interactions provient du mouvement du robot, une étude détaillée de la dynamique du robot fut aussi réalisée, d'abord pour la caractériser, mais aussi dans l'objectif d'enrichir les possibilités d'interactions reliées au mouvement. La modélisation de la dynamique a permis de conclure que les capacités motrices sont principalement influencées par le ratio masse suspendue sur la masse totale du robot. Il est maintenant possible de déterminer la hauteur maximale d'obstacle et la pente maximale que le robot peut franchir, et cela pour toute configuration géométrique et pour différentes répartitions de masses. Un modèle tridimensionnel a aussi été obtenu. Ce dernier a permis d'étudier différentes trajectoires ainsi que le mouvement circulaire. Enfin, deux séries d'expériences ont été réalisées avec Roball utilisé comme jouet avec des enfants de 12 à 24 mois. Celles-ci ont permis de confronter le nouveau prototype de Roball à la réalité. Afin de conduire ces expériences, une démarche scientifique a été suivie pour cerner la problématique et les hypothèses et pour définir une méthodologie et un protocole expérimental. Si un constat sans équivoque ne peut être dégagé concernant l'effet du mouvement de Roball sur l'attention et la mobilité des enfants, plusieurs recommandations sont émises en vue d'expériences futures

L'impact des mécanismes de fédéralisme exécutif sur le déficit fédératif canadien

Le Canada accuse un déficit fédératif en ce sens où il existe des écarts importants entre le fonctionnement de la fédération canadienne et les caractéristiques du système fédéral élaborées par les spécialistes du fédéralisme. Les deux ordres de gouvernement, censés être coordonnés et indépendants, sont, au Canada, hiérarchisés, laissant au gouvernement central un pouvoir nettement supérieur à celui des États provinciaux. Celles-ci, qui devraient avoir une autonomie financière et les ressources suffisantes pour gérer adéquatement leurs sphères de compétence, se retrouvent souvent à la remorque du gouvernement fédéral pour obtenir des transferts de paiement et instaurer des plans d'action. Les institutions politiques fédérales laissent très peu de place à la participation des États provinciaux dans la prise de décision centrale. De plus, les minorités nationales sont souvent exclues ou sous-représentées lors des débats politiques. Comme mécanismes de relations intergouvernementales, les Conférences des premiers ministres et le Conseil de la fédération pourraient jouer un rôle déterminant dans l'atténuation du déficit fédératif canadien. Pourtant, peu institutionnalisées, mal utilisées et surtout mal conçues, ces instances ne font que reproduire les lacunes de la fédération canadienne. Après avoir établi ce qu'est le principe fédéral et en avoir extrait les principaux éléments, et après avoir étudié le fonctionnement des Conférences des premiers ministres et du Conseil de la fédération, ce mémoire traite de l'impact qu'ont ces derniers sur le déficit fédératif canadien, c'est-à-dire sur les lacunes existant dans la fédération canadienne lorsqu'elle est mise en relation avec les théories du fédéralisme.\ud _____________________________________________________________________________

Tracking Landscape-Scale Movements of Snow Buntings and Weather-Driven Changes in Flock Composition During the Temperate Winter

Nomadic movements of migratory birds are difficult to study, as the scale is beyond the capabilities of hand-held telemetry (10 s of kms) but too fine-scale for long-range tracking devices like geolocators (50–100 km accuracy). Recent widespread installation of automated telemetry receiving stations allowed us, for the first time, to quantify and test predictions about within-winter movements of a presumed nomadic species, the Snow Bunting (Pletrophenax nivalis). We deployed coded radio-transmitters on 40 individual Snow Buntings during two winters (2015-16 and 2016-17) in southern Ontario, Canada, and tracked movements over a 300 by 300 km area with 69–77 active radio-receiving stations (Motus Wildlife Tracking Network). To complement our tracking data, we also examined the influence of weather on the demographics of winter flocks at a single wintering site over 6 consecutive years (n = 9312 tagged birds). We recorded movements of 25 Snow Buntings from the deployment sites to 1–6 different radio recievers (mean 2.68 locations/bird). Birds traveled a minimum average distance of 49 km between detections (range: 3 to 490 km) in the core wintering period of Dec-Feb, and cumulative total movements ranged from 3 to 740 km (average 121 ± 46 km). In March distances between detections increased to an average of 110 km, suggesting an extended early-migration period. Overall, older birds (after-second year or older) tended to move more (higher cumulative distances traveled) than younger (first winter) birds, even during the Dec-Feb period. The long-term banding data revealed that larger, male birds were more likely to be captured in colder and snowier weather, relative to female and smaller birds, suggesting that they can withstand these conditions more easily owing to their body size. We have provided the first direct-tracking data on nomadic winter movements of Snow Buntings, and tested the hypothesis that winter weather drives flock composition at a single site. Site-specific banding data suggest that weather-related changes in flock composition could explain the nomadic, landscape-scale movements of Snow Buntings we observed by using automated telemetry. Future work should explore the importance of resource availability, competition, and predation risk as drivers of winter movements in Snow Buntings

Geometallurgical Study of a Gravity Recoverable Gold Orebody

Sheeted vein gold deposits are often characterised by multiple sub-parallel veins and free-milling coarse gold. Inherent mineralisation heterogeneity results in grade and process parameter variability, which increases project risk if not quantified. Measured grade variability is often exacerbated by poorly designed sampling and testwork protocols. Protocols that are optimised within the framework of the Theory of Sampling (TOS) to suit the ore type, together with quality assurance/quality control systems, will reduce variability and provide fit for-purpose results. Geometallurgy can be broadly split into two key approaches: strategic and tactical (or operational). The strategic approach focuses on the whole orebody and long-term life-of-mine view, whereas tactical geometallurgy relates to a more short- to medium term view during mining. The geometallurgical approach requires spatially distributed samples within a deposit to support variability modelling. Diverse attributes from core logging, mineralogical/textural determination and small-scale tests are used to measure variability. This contribution presents a case study that emphasises an early-stage strategic geometallurgical programme applied to a gravity recoverable gold (GRG) dominated deposit. It exemplifies how data can be acquired from a well-designed and planned programme to support resource estimation, a pre-feasibility study, trial mining and fast-track to production. A tactical geometallurgical programme is embedded into the mine operation

Snow Buntings Maintain Winter-Level Cold Endurance While Migrating to the High Arctic

Arctic breeding songbirds migrate early in the spring and can face winter environments requiring cold endurance throughout their journey. One such species, the snow bunting (Plectrophenax nivalis), is known for its significant thermogenic capacity. Empirical studies suggest that buntings can indeed maintain winter cold acclimatization into the migratory and breeding phenotypes when kept captive on their wintering grounds. This capacity could be advantageous not only for migrating in a cold environment, but also for facing unpredictable Arctic weather on arrival and during preparation for breeding. However, migration also typically leads to declines in the sizes of several body components linked to metabolic performance. As such, buntings could also experience some loss of cold endurance as they migrate. Here, we aimed to determine whether free-living snow buntings maintain a cold acclimatized phenotype during spring migration. Using a multi-year dataset, we compared body composition (body mass, fat stores, and pectoralis muscle thickness), oxygen carrying capacity (hematocrit) and metabolic performance (thermogenic capacity – Msum and maintenance energy expenditure – BMR) of birds captured on their wintering grounds (January–February, Rimouski, QC, 48°N) and during pre-breeding (April–May) in the Arctic (Alert, NU, 82°). Our results show that body mass, fat stores and Msum were similar between the two stages, while hematocrit and pectoralis muscle thickness were lower in pre-breeding birds than in wintering individuals. These results suggest that although tissue degradation during migration may affect flight muscle size, buntings are able to maintain cold endurance (i.e., Msum) up to their Arctic breeding grounds. However, BMR was higher during pre-breeding than during winter, suggesting higher maintenance costs in the Arctic

Revue d'histoire du Bas-Saint-Laurent, vol. 12 (3-4)

Mot de l'éditeur -- Au micro de CJBR -- La grande histoire de CJBR -- Jules-A. Brillant et le poste CJBR -- Avec CJBR, un bon en avant pour le Bas St-Laurent -- CJBR, l'école -- L'annonceur: un éducateur populaire -- Sandy Burgess : le journaliste que j'ai connu -- "Ce pays qui est le mien" -- Un demi-siècle d'information: que de nouvelles! -- Journaliste de père en fils à CJBR -- Le théâtre à CJBR -- 50 ans de musique à CJBR, le château fort de la mélodie française -- Poésie, théâtre, jazz et originalité avec Michel Garneau -- Les "Chroniques du dimanche", l'âge d'or de la critique culturelle à CJBR -- "Si CJBR m'était conté..." -- L'évolution technologique, un élément-clef de l'histoire des 50 ans de radiodiffusion -- La publicité à CJBR, quarante ans de croissance -- Des pionnières à CJBR -- 1958-1972, des années enrichissantes -- De Trois-Pistoles à Rimouski -- Le sport et son enracinement dans le milieu régional -- "Debout c'est l'heure", c'est Jean Brisson qui sonne le réveil -- "Par une belle journée de tempête" -- Et on repart vers la centain

Patients' and Practitioners' Views of Knee Osteoarthritis and Its Management: A Qualitative Interview Study

PURPOSE: To identify the views of patients and care providers regarding the management of knee osteoarthritis (OA) and to reveal potential obstacles to improving health care strategies. METHODS: We performed a qualitative study based on semi-structured interviews of a stratified sample of 81 patients (59 women) and 29 practitioners (8 women, 11 general practitioners [GPs], 6 rheumatologists, 4 orthopedic surgeons, and 8 [4 GPs] delivering alternative medicine). RESULTS: Two main domains of patient views were identified: one about the patient-physician relationship and the other about treatments. Patients feel that their complaints are not taken seriously. They also feel that practitioners act as technicians, paying more attention to the knee than to the individual, and they consider that not enough time is spent on information and counseling. They have negative perceptions of drugs and a feeling of medical uncertainty about OA, which leads to less compliance with treatment and a switch to alternative medicine. Patients believe that knee OA is an inevitable illness associated with age, that not much can be done to modify its evolution, that treatments are of little help, and that practitioners have not much to propose. They express unrealistic fears about the impact of knee OA on daily and social life. Practitioners' views differ from those of patients. Physicians emphasize the difficulty in elaborating treatment strategies and the need for a tool to help in treatment choice. CONCLUSIONS: This qualitative study suggests several ways to improve the patient-practitioner relationship and the efficacy of treatment strategies, by increasing their acceptability and compliance. Providing adapted and formalized information to patients, adopting more global assessment and therapeutic approaches, and dealing more accurately with patients' paradoxal representation of drug therapy are main factors of improvement that should be addressed

Crowdsourcing hypothesis tests: Making transparent how design choices shape research results

To what extent are research results influenced by subjective decisions that scientists make as they design studies? Fifteen research teams independently designed studies to answer fiveoriginal research questions related to moral judgments, negotiations, and implicit cognition. Participants from two separate large samples (total N > 15,000) were then randomly assigned to complete one version of each study. Effect sizes varied dramatically across different sets of materials designed to test the same hypothesis: materials from different teams renderedstatistically significant effects in opposite directions for four out of five hypotheses, with the narrowest range in estimates being d = -0.37 to +0.26. Meta-analysis and a Bayesian perspective on the results revealed overall support for two hypotheses, and a lack of support for three hypotheses. Overall, practically none of the variability in effect sizes was attributable to the skill of the research team in designing materials, while considerable variability was attributable to the hypothesis being tested. In a forecasting survey, predictions of other scientists were significantly correlated with study results, both across and within hypotheses. Crowdsourced testing of research hypotheses helps reveal the true consistency of empirical support for a scientific claim.</div