1,721,027 research outputs found
Nurse practitioners: Improving access to primary care on Prince Edward Island
No full textPresently, 8200 Prince Edward Island (PEI) residents do not have access to a family physician or primary care. Effective integration of nurse practitioners (NP) will improve access to this care with equivalent health outcomes. This document evaluates the effectiveness of integrating the NP role in two primary care collaborative models on PEI, and compares collaborative and non-collaborative models with respect to access and quality of care. This paper also shows that an existing Ontario NP led clinic model is effective in improving access to primary care. Findings demonstrate that integrating NPs in collaborative models can improve access to care, health outcomes and patient satisfaction
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Convection in the primitive mantle in interaction with global magma oceans
No full textUn scénario couramment considéré lors de la formation des planètes telluriques est celui des océans de magma. L'énergie d’accrétion ainsi que celle dégagée par la désintégration d’éléments radioactifs de courtes périodes est en effet largement suffisante pour fondre une large portion voire l'entièreté du manteau terrestre, formant dans ce dernier cas un océan de magma global. La dépendance en pression de la température de solidification et le fort gradient du profil isentropique dans le manteau inférieur peut ammener à une cristallisation decet océan de magma global par le milieu. Ceci conduit à une situation où la partie solide du manteau primitif est encadrée par deux océans de magma globaux : un en surface, et un basal. Cette thèse se focalise sur deux aspects scientifiques d'un tel système. D'une part, les océans de magma ayant une composition similaire à celle du solide, la matière en convection dans le solide n'est pas nécessairement arrêtée à l'interface entre le solide et le liquide mais peut la traverser par fusion/cristallisation si le temps de changement de phase est court devant le temps de construction de topographie du solide au sein du liquide par force visqueuse. Une analyse de stabilité linéaire ainsi que des simulations numériques directes montrent que cette possibilité de changement de phase affecte considérablement la convection dans la partie solide. Le nombre de Rayleigh critique est abaissé, les structures convectives ont une plus grande longeur d'onde, et le flux de chaleur transporté à travers la couche solide peut être de plusieurs ordres de grandeurs plus important qu'avec des conditions aux limites classiques. Le deuxième aspect étudié durant cette thèse est celui de l'évolution à long terme du manteau primitif. En couplant le modèle de convection dans le solide avec des modèles simples d'évolution des océans de magma, nous avons construit un modèle d'évolution global du manteau primitif en suivant l'évolution thermo-compositionelle des océans de magma globaux et de la partie solide. Une analyse de stabilité linéaire montre que la convection dans la partie solide démarre avant même que l'océan de magma en surface soit entièrement cristallisé. Une simulation numérique directe préliminaire montre que la cristallisation fractionnée de l’océan de magma basal peut conduire à la formation de larges piles thermochimiques en base du manteau solide, similaires aux structures de faibles vitesses sismiques (LLSVP) observées de nos jours. La présence d'océans de magma globaux peut donc avoir d'importantes répercussions sur l'évolution à long terme de la Terre : d'une part via les structures thermiques et compositionnelles mises en place par la cristallisation fractionnée des océans et la convection dans le solide ; d'autre part, le bilan énergétique global peut être considérablement affecté par le fort flux de chaleur extrait par le manteau solide du fait des conditions de changement de phase.A common scenario considered during the formation of Earth-like bodies is that of magma oceans. Indeed, the accretion energy as well as the heat produced by the radioactive decay of short-period elements is more than enough to melt entirely the primitive mantle, thereby forming a global magma ocean. The pressure-dependence of the solidification temperature as well as the steep isentropic temperature profile at the base of the mantle could lead to a crystallization of that global magma ocean from the middle. The primitive solid mantle could therefore be bounded by two global magma oceans: one above and one below.This PhD thesis focuses on two aspects of such a system. First, the solid part of the mantle and the magma oceans being of similar composition, convecting matter in the solid is not necessarily stopped by the solid/liquid interface but could instead go through it by melting/freezing provided that the phase change timescale is short enough compared to the viscous timescale needed to build a solid topography in the liquid oceans. A linear stability analysis and direct numerical simulations show the phase change at the boundary greatly affects convection in the solid part of the mantle. The critical Rayleigh number decreases, convective patterns have a larger wavelength, and the heat flux carried through the solid increases of up to several orders of magnitude compared to cases with classical boundary conditions.The second aspect explored in this thesis is the long-term evolution of the primitive mantle. Coupling convection in the solid with simple evolution models for the magma oceans allowed us to build a global evolution model of the primitive mantle monitoring the thermo-compositional evolution of the solid mantle and magma oceans. A linear stability analysis shows convection sets in the solid before the surface magma ocean crystallizes entirely. A preliminary direct numerical simulation shows the fractional crystallization of the basal magma ocean may lead to the formation of large thermo-chemical piles at the base of the solid mantle. These piles are similar to the large low-shear velocity provinces (LLSVP) observed today.The presence of global magma oceans could therefore have important consequences on the long-term evolution of the Earth: first, fractional crystallization of the magma oceans and convection in the solid part affect the resulting thermal and compositional structures; and second, the global heat budget could be tremendously affected by the high heat flux carried out by the solid part owing to the phase change boundary conditions
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Convection dans les glaces de haute pression des satellites de Jupiter et Saturne
No full textDans notre système planétaire, il existe de nombreux objets connus sous le nom de « lunes glacées ». Plusieurs de ces lunes abritent un océan souterrain composé principalement d’eau liquide, ce qui permet aussi de classifier ces lunes comme « mondes océans ». Les petites lunes glacées, comme Encelade et Europe, sont composées d’un océan souterrain entre une couche de glace à la surface et un noyau rocheux, ce qui permet de fortes interactions eau-roche qui en font des objets intéressants à étudier pour la recherche de vie dans le système solaire. Cependant, sur les grandes lunes glacées comme Ganymède et Titan, une couche de glaces de haute pression existerait entre l’océan et le noyau à cause des hautes pressions expérimentées par ces lunes, composées d’une hydrosphère très épaisse. A première vue, cette couche de glace empêche un contact direct ainsi que les échanges de sels, et éventuellement de nutriments, entre le noyau rocheux et l'océan. Par conséquent, la question est : « Ces échanges sont-ils possibles et peuvent-ils être efficaces ? » Cette thèse se concentre sur différents aspects du problème qui n’ont pas été considérés par les quelques précédentes études sur le sujet. Tout d’abord, on étudie les effets du changement de phase existant à l’interface entre l’océan et la couche de glace de haute pression. La prise en compte de ce changement de phase modifie radicalement la dynamique, permettant une vitesse radiale non nulle à l’interface. On montre que cette condition aux limites facilite la convection et permet à la glace de haute pression, sous certaines conditions et pour divers corps planétaires, de fondre à l’interface avec le noyau rocheux, ce qui favorise les échanges entre le noyau et l’océan. Deuxièmement, on ajoute des sels dans notre modèle afin d’en étudier les effets sur la dynamique. Le peu d’études antérieures à ce sujet de thèse considère uniquement une couche de glace d’eau pure, alors que les océans de ces lunes sont à priori salés. Une partie de ces sels proviendrait de la différentiation de ces corps, tandis qu’une autre pourrait provenir des échanges avec le noyau, d’où l’importance de considérer ces sels dans nos modèles et d’étudier l’efficacité de ces échanges. En ajoutant des sels à notre modèle, on montre qu’il existe deux régimes d’évolution des sels dans la couche de glace de haute pression, en fonction de leur effet sur la densité de la glace. On montre également que des échanges efficaces peuvent avoir lieu entre le noyau et l’océan et qu’en fonction du régime dans lequel on se trouve, une quantité importante de sels peut atteindre l'océan. Enfin, les résultats obtenus en ajoutant un flux de sels provenant du noyau rocheux dans la couche de glace de haute pression ont mis en évident l’existence possible, dans certains cas, d’un mince océan très salé entre le noyau et la glace de haute pression, que nous avons commencé à étudié dans cette thèse.In our planetary system, there are many planetary objects known as icy moons. Several of these moons home a subsurface liquid ocean mainly composed of water, which also classifies them as ocean worlds. Small icy moons, as Enceladus or Europa, are composed of an ocean between an icy surface and a rocky core, allowing strong interactions between liquid water and rocks, which make them interesting for the search for life in the solar system. However, on large icy moons as Ganymede or Titan, a layer of high-pressure (HP) ices may exist between the ocean and the rocky core due to the high pressure experienced by these moons composed of a very deep hydrosphere. At first glance, this layer prevents direct contact and exchanges of salts, and possibly nutrients, between the rocky core and the ocean. Therefore, the question is: are those exchanges possible and could they be efficient? This PhD thesis focuses on several aspects not considered in the few previous studies carried out on this subject. The first one is the effect of the phase equilibrium at the interface between the high-pressure ice layer and the ocean. It can be modelled as a phase change boundary condition and drastically changes the dynamics, allowing a non-zero radial velocity at the top interface. We show that this boundary condition eases the convection and allows, under certain conditions for various planetary bodies, melt to form at the interface between the core and the high-pressure ice shell, which enhances the exchanges between the core and the ocean. Secondly, we added salts into our model to study their effect on the overall dynamics. The few studies already existing on this topic focused only on pure water ice, while the oceans of these moons are likely to be composed of salty water. Part of these salts may come from the interactions with the core, hence the importance of studying the efficiency of these exchanges. By adding salts to our model, we show that there are two regimes for how the salts behave in the high-pressure ice layer, depending on how much they affect the ice density. We also show that efficient exchanges of salts can happen through the high-pressure ice shell and that, depending on the regime just mentioned, a significant amount of salts can reach the ocean. Finally, the results obtained by including salts from the core in the high-pressure ice layer highlighted the possible formation of a thin highly-salted basal ocean between the core and the ice, which we started to study in this PhD thesis
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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