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Curriculum development in Canada has gone from teaching survival skills, both practical and cultural, to emphasizing self-fulfillment and standards-based achievements. This evolution mirrors that which has occurred in other developed countries, namely in Europe.

Planification systématique de ce qui est enseigné et appris dans les écoles et qui se reflète dans les cours et dans les programmes scolaires, consignés dans des documents officiels (qui servent en général de « guides » pour les programmes d'études pour les enseignants) et rendus obligatoires par les ministères de l'Éducation des provinces et des territoires.

This paper discusses the curriculum in relation to civic education and national consciousness and to emerging programs in Canadian Studies, focussing on the work of the Canada Studies Foundation. It stresses the need in Canadian Studies for a non-ideological approach that will enable students to confront and consider diverse interpretations of the Canadian experience. Canadian Studies is defined broadly to include the social sciences and humanities and to take account of skills, values and attitudes as well as content.

Masks reduce transmission of SARS-CoV2 and other respiratory pathogens. Comparative studies of the fitted filtration efficiency of different types of masks are scarce. To describe the fitted filtration efficiency against small aerosols (0.02-1 µm) of medical and non-medical masks and respirators when worn, and how this is affected by user modifications (hacks) and by overmasking with a cloth mask. We tested a 2-layer woven-cotton cloth mask of a consensus design, ASTM-certified level 1 and level 3 masks, a non-certified mask, KF94s, KN95s, an N95 and a CaN99. Closed rooms with ambient particles supplemented by salt particles. 12 total participants; 21-55 years, 68% female, 77% white, NIOSH 1-10. Using standard methods and a PortaCount 8038, we counted 0.02-1 µm particles inside and outside masks and respirators, expressing results as the percentage filtered by each mask. We also studied level 1 and level 3 masks with earguards, scrub caps, the knot-and-tuck method, and the effects of braces or overmasking with a cloth mask. Filtration efficiency for the cloth mask was 47-55%, for level 1 masks 52-60%, for level 3 masks 60-77%. A non-certified KN95 look-alike, two KF94s, and three KN95s filtered 57-77%, and the N95 and CaN99 97-98% without fit testing. External braces and overmasking with a well-fitting cloth mask increased filtration, but earguards, scrub caps, and the knot-and-tuck method did not. Limited number of masks of each type sampled; no adjustment for multiple comparisons. Well-fitting 2-layer cotton masks filter in the same range as level 1 masks when worn: around 50%. Level 3 masks and KN95s/KF94s filter around 70%. Over a level 1 mask, external braces or overmasking with a cloth-mask-on-ties produced filtration around 90%. Only N95s and CaN99s, both of which have overhead elastic, performed close to the occupational health and safety standards for fit tested PPE (>99%), filtering at 97-99% when worn, without formal fit testing. These findings inform public health messaging about relative protection from aerosols afforded by different mask types and explain the effectiveness of cloth masks observed in numerous epidemiologic studies conducted in the first year of the pandemic. A plain language summary of these findings is available at https://maskevidence.org/masks-compared.

Reaction-induced porosity is a key factor enabling protracted fluid-rock interactions in the Earth’s crust, promoting large-scale mineralogical changes during diagenesis, metamorphism, and ore formation. Here, we show experimentally that the presence of trace amounts of dissolved cerium increases the porosity of hematite (Fe 2 O 3 ) formed via fluid-induced, redox-independent replacement of magnetite (Fe 3 O 4 ), thereby increasing the efficiency of coupled magnetite replacement, fluid flow, and element mass transfer. Cerium acts as a catalyst affecting the nucleation and growth of hematite by modifying the Fe 2+ (aq)/Fe 3+ (aq) ratio at the reaction interface. Our results demonstrate that trace elements can enhance fluid-mediated mineral replacement reactions, ultimately controlling the kinetics, texture, and composition of fluid-mineral systems. Applied to some of the world’s most valuable orebodies, these results provide new insights into how early formation of extensive magnetite alteration may have preconditioned these ore systems for later enhanced metal accumulation, contributing to their sizes and metal endowment. Trace amounts of Cerium can act as a catalyst by enhancing fluid-mediated magnetite alteration, which preconditions ore systems and could contribute to the large size and metal content of world-class ore deposits.

[This corrects the article DOI: 10.1371/journal.pone.0301310.].