En France, les inégalités scolaires restent un problème majeur. En effet, la reproduction des inégalités et le déterminisme social continuent de teinter la réussite des jeunes : la quête pour l’égalité des chances se poursuit. Agir sur la pédagogie pourrait être considérée comme l’une des voies pour l’édification d’une école plus juste. Notre revue de la portée vise donc à interroger la contribution des pédagogies nouvelles (PN), héritières du projet socio-politique de l’Éducation nouvelle, face à l’égalité des chances. Notre corpus composé de 17 études synthétise les effets des PN observés auprès de jeunes de milieux sociaux défavorisés. Notre thèse dévoile la capacité des PN à soutenir la réussite de tous les élèves grâce à certaines conditions pédagogiques et didactiques, propres à leurs principes fondamentaux. Si les PN ont le potentiel de contribuer à la réduction des inégalités, nous montrons l’intérêt et la nécessité de les démocratiser, de leur donner une chance.

Cognitions relevant to tanning salon decision making were studied using Jaccard's Theory of Alternative Behavior. Questionnaires were administered assessing tanning salon use, attitudes toward tanning salon use, attitudes toward reasonable behavioral alternatives, and cognitive variables underlying these variables. Tanning salon use reports were very high in this sample. The results support the notion that young people make decisions regarding using tanning salons based on the behavioral alternatives available to them. Specifically, subjects with stronger preferences for using clothing to enhance appearance were less likely to use tanning salons. Furthermore, the multivariate approach used clearly delineates the specific cognitive beliefs and orientations that might be targeted to change these attitudes. The relevance of these findings to skin cancer prevention is discussed.

Ordered alternatives tests are sometimes used in life-testing experiments and drug-screening studies. An ordered alternative test is sometimes used to gain power if the researcher thinks parameters will be ordered in a certain way if they are different. This research proposal focuses on developing new nonparametric tests for the nondecreasing ordered alternative problem for k (k?3) populations when testing for differences in both location and scale. Six nonparametric tests are proposed for the nondecreasing ordered alternative when testing for a difference in either location or scale. The six tests are various combinations of a well-known ordered alternatives test for location and a test based on the Moses test technique for testing differences in scale. A simulation study is conducted to determine how well the proposed tests maintain their significance levels. Powers are estimated for the proposed tests under a variety of conditions for three, four and five populations. Several types of variable parameters are considered: when the location parameters are different and the scale parameters are equal; when the location parameters are equal and the scale parameters are different; when the location and scale parameters are both different. Equal and unequal samples sizes of 18 and 30 are considered. Subgroup sizes of 3 and 6 are both used when applying the Moses test technique. Recommendations are given for which test should be used for various situations.

[EN] Climate change is one of the short term threats for the humanity because it can affect seriously to the environment and, consequently, to vegetal and animal life. If it is not stopped in next years, maybe this effect will be irreversible. Climate change is produced by anthropogenic emissions of Greenhouse Gas to Earth's atmosphere. Vapour compression systems are one of the main contributors to this phenomenon. Among them, commercial refrigeration applications, through HFC usage, can be highlighted. Since 1990s, developed countries supermarkets are using refrigerants (mainly R134a, R404A and R507A) with great impact (high GWP values) on the climate change due to leakages, especially from parallel compressor rack DX systems. Recently, some regulations and directives have been approved to limit GWP values of HFC used in most extended refrigeration and air conditioning applications, directly affecting to commercial refrigeration. In this thesis, some low-GWP alternatives to replace the most commonly used HFC refrigerants in commercial refrigeration are evaluated, taking into account the limitations imposed by these regulations. To carry out this evaluation, the current status of parallel compressor rack refrigeration systems and their fluids has been reviewed. Then, the different low-GWP options to replace R134a and R404A have been studied. HFOs and their mixtures with HFC have been highlighted as the most promising drop-in or retrofit alternatives. Thus, R1234yf, R1234ze(E) and R450A were proposed to replace R134a and R448A to substitute R404A. The theoretical performance of the different low-GWP alternative fluids, as an overview of their potential use, has been studied at typical parallel compressor rack refrigeration operating conditions using the basic thermodynamic vapour compression cycle. Given the good theoretical performance of these refrigerants, they have been tested in a vapour compression test bench. From the experimental results it is depicted that R1234yf and R1234ze(E) are not acceptable as drop-in or light retrofit refrigerants from an energetic point of view. These fluids, when used in R134a systems, require system modifications (more severe in the case of R1234ze(E)) to achieve acceptable energy efficiency values. Moreover, due to the large refrigerant charge in PCRRS, both HFOs could present problems relating to security. Thus, while R450A presents a GWP value of 547, it appears as the best option to replace R134a due to the similar energy efficiency and properties. Its experimental mass flow rate and cooling capacity are slightly lower than R134a, but the final COP is approximately the same. The best R450A results when compared to R134a are obtained at higher CRs. Although can obtain better efficiency results in new systems, with a minor TXV adjustment R448A shows very high performance when it is used in R404A systems. Despite R448A lower cooling capacity than that R404A, this HFC/HFO mixture can achieve great CO2 equivalent emission reductions and it is recommended as lower-GWP replacement for R404A. / [ES] El cambio climático es una amenaza para la humanidad ya que puede afectar seriamente al medio ambiente y, en consecuencia, a la vida animal y vegetal. Si en los próximos años no se actúa para detenerlo, tal vez este efecto sea irreversible. Entre otros factores, el incremento de la temperatura global es producido por las emisiones antropogénicas de gases de efecto invernadero a la atmósfera. La refrigeración comercial, basada en sistemas de compresión de vapor, contribuye de forma relevante a este fenómeno a través del uso de fluidos sintéticos como refrigerantes y del consumo de energía eléctrica procedente de combustibles fósiles. Desde la última década del siglo XX, los supermercados de países desarrollados utilizan HFCs como fluidos de trabajo, principalmente R134a, R404A y R507A. Estos gases, de alto potencial de calentamiento atmosférico (PCA), contribuyen al cambio climático al fugarse accidentalmente de los sistemas de refrigeración, destacando las centrales de compresores en paralelo conectadas a sistemas de expansión directa. El valor máximo de PCA de los HFCs utilizados en aplicaciones de refrigeración y aire acondicionado va a ser controlado por normativas comunitarias, afectando directamente a los fluidos usados comúnmente en refrigeración comercial. Esta tesis evalúa diferentes alternativas de bajo PCA para sustituir los refrigerantes HFC más utilizados en refrigeración comercial, teniendo en cuenta las limitaciones impuestas por las normativas actuales. Para llevar a cabo dicho estudio, se revisa el estado actual de los sistemas de centrales de compresores en paralelo y sus fluidos. A continuación, se analizan las diferentes opciones de bajo PCA para sustituir al R134a y R404A. Al destacar los HFOs y sus mezclas con HFCs como alternativas para realizar un reemplazo con pocas modificaciones del sistema (propiedades similares); R1234yf, R1234ze(E) y R450A son propuestos para sustituir al R134a y R448A para R404A. El rendimiento teórico de los diferentes fluidos alternativos de bajo PCA, para obtener una visión general del potencial de su uso, se estudia simulando las condiciones operativas típicas de las centrales de compresores en paralelo, usando el ciclo termodinámico de compresión de vapor básico. Dado el buen rendimiento mostrado por estos refrigerantes, son ensayados en un banco de pruebas de compresión de vapor. De los resultados experimentales se observa que R1234yf y R1234ze(E) no son aceptables desde un punto de vista energético como sustitutivos directos o con menores modificaciones. Dichos fluidos, cuando son utilizados en sistemas de R134a, requieren modificaciones del sistema (más severas en el caso del R1234ze(E)) para alcanzar valores aceptables de eficiencia energética. Por otra parte, debido a la gran carga necesaria en PCRRS, ambos HFOs podrían presentar problemas en cuanto a la seguridad. Así, mientras que el R450A presenta un valor de PCA de 547, aparece como la mejor opción para sustituir al R134a debido a una eficiencia energética y propiedades similares. El caudal másico y la capacidad frigorífica del R450A son ligeramente inferiores en comparación con las del R134a, pero por otra parte, el COP resultante es aproximadamente el mismo. Los mejores resultados obtenidos para R450A son obtenidas a altas tasas de compresión. Aunque puede ser obtenida una eficiencia energética más alta en sistemas de nuevo diseño, con sólo un ajuste menor de la válvula de expansión termostática, el R448A muestra valores muy altos de rendimiento en sistemas utilizados con R404A. A pesar de que la capacidad frigorífica del R448A es menor que la del R404A, esta mezcla de HFC y HFO puede dar lugar a grandes reducciones de emisiones de CO2 equivalentes, siendo así recomendado como reemplazo del R404A con menor PCA. / [CA] El canvi climàtic és una amenaça per a la humanitat ja que pot afectar seriosament el medi ambient i, en conseqüència, la vida animal i vegetal. Si en els propers anys no s'actua per aturar-lo, potser aquest efecte siga irreversible. Entre altres factors, l'increment de la temperatura global és produït per les emissions antropogèniques de gasos d'efecte hivernacle a l'atmosfera. La refrigeració comercial, basada en sistemes de compressió de vapor, contribueix de manera rellevant a aquest fenomen per l'ús de fluids sintètics com refrigerants i pel consum d'energia elèctrica procedent de combustibles fòssils. Des de l'última dècada del segle XX, els supermercats dels països desenvolupats utilitzen HFCs com fluids de treball, principalment R134a, R404A i R507A. Aquests gasos, d'alt potencial d'escalfament atmosfèric (PCA en castellà), contribueixen al canvi climàtic quan s'escapen accidentalment dels sistemes de refrigeració. D'aquest tipus de sistemes destaquen com a grans emissors de diòxid de carboni les centrals de compressors en paral·lel connectades a sistemes d'expansió directa. El valor màxim de PCA dels HFCs utilitzats en aplicacions de refrigeració i aire condicionat serà controlat per normatives comunitàries, cosa que afectarà directament els fluids utilitzats a la gran majoria de sistemes de refrigeració comercial. Aquesta tesi avalua diferents alternatives de baix PCA per substituir els refrigerants HFC més utilitzats en refrigeració comercial sense oblidar les limitacions imposades per les normatives actuals. Per dur a terme aquest estudi, es revisa l'estat actual dels sistemes de centrals de compressors en paral·lel i els seus fluids. A continuació, s'analitzen les diferents opcions de baix PCA per substituir l'R134a i l'R404A. Els HFOs i les seves mescles amb HFCs com alternatives destaquen per permetre una substitució amb poques modificacions del sistema (propietats similars); R1234yf, R1234ze(E) i R450A són proposats per substituir l'R134a i R448A per l'R404A. Per obtenir una visió general del potencial de l'ús dels diferents fluids alternatius de baix PCA, s'estudia el seu rendiment teòric mitjançant una simulació de les condicions operatives típiques de les centrals de compressors en paral·lel. Per a aquesta simulació s'empra el cicle termodinàmic de compressió de vapor bàsic. Com a conseqüència del bon rendiment mostrat per aquests refrigerants, són assajats en un banc de proves de compressió de vapor. Dels resultats experimentals s'observa que R1234yf i R1234ze(E) no són acceptables des d'un punt de vista energètic com a substitutius directes o amb menors modificacions. Aquests fluids, quan són utilitzats en sistemes de R134a, requereixen modificacions del sistema (més severes en el cas de l'R1234ze(E)) per assolir valors acceptables d'eficiència energètica. D'altra banda, a causa de la gran càrrega necessària en PCRRS, tots dos HFOs podrien presentar problemes en temes de seguretat. Així, mentre que el R450A presenta un valor de PCA de 547, apareix com la millor opció per substituir l'R134a a causa de una eficiència energètica i propietats similars. El cabal màssic i la capacitat frigorífica de l'R450A són lleugerament inferiors en comparació amb les de l'R134a, però d'altra banda, el COP resultant és aproximadament el mateix. Els millors resultats de l'R450A són obtinguts a altes taxes de compressió. Tot i que pot ser obtinguda una eficiència energètica més alta en sistemes de nou disseny, amb només un ajust menor de la vàlvula d'expansió termostàtica, l'R448A mostra valors molt alts de rendiment en sistemes utilitzats amb R404A. Encara que la capacitat frigorífica de l'R448A és menor que la de l'R404A, aquesta barreja de HFCs i HFO pot aconseguir grans reduccions d'emissions de CO2 equivalents, i es per tant es recomanada com a reemplaçament amb menor PCA de l'R404A. / Mota Babiloni, A. (2016). ANALYSIS OF LOW GLOBAL WARMING POTENTIAL FLUORIDE WORKING FLUIDS IN VAPOUR COMPRESSION SYSTEMS. EXPERIMENTAL EVALUATION OF COMMERCIAL REFRIGERATION ALTERNATIVES [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62680 / TESIS / Premios Extraordinarios de tesis doctorales

Thesis (M.Com. (Information Systems))--University of the Witwatersrand, Faculty of Commerce, Law and Management, School of Economic and Business Sciences, 2015. / This research study investigated the key factors that contribute to both current usage and future usage intention of online banking by South African users. The research was focused on online banking from all banks and regions in South Africa, hence making the results generalisable to the South African context. The variables (Performance Expectancy, Effort Expectancy, Facilitating Conditions and Social Influence) were derived from UTAUT model. Trust, Switching Costs and Availability of Alternatives were also added. The conceptual model was moderated by age, gender and experience. The variables used within the study were derived from literature review based on previous studies. From a survey of 300 online banking consumers, results were drawn from 105 responses. In South Africa, Trust, Effort expectancy and facilitating conditions, presented significant and positive impact on future usage intention of using online banking. Age and Experience were also significant to Future Usage intentions. However Social Influence, Switching Costs and Availability of Alternatives do not play a considerable role in influencing the user’s future usage in South Africa. While current usage did not directly impact future usage intentions of using online banking, the findings on frequency of usage and functionality (applications) added value to understanding the concept of current usage. The model had an R2 = 0.25 which suggests that within the South African context, there are more factors to be considered for academia and practitioners to understand online banking behaviour amongst consumers. We cannot completely apply theories and models from other countries to the South African context. There is a need to look at factors unique to South Africa, including how customers interpret questionnaires. The research also contributes to the current body of work and interest by banks in South Africa to move from “bricks to clicks”, (moving customers from the branches onto electronic platforms) that are more accessible from any location, and require less staff to operate. To do that, practitioners need add “trust” factors to online banking as well as increase frequency of users logging on to transact. It is vital for banks to also focus on functionality that is simple, reliable and dependable, as well as adds value to customers to ensure their frequent and continued usage thereof.

The transport sector is a major contributor to the rise in global temperatures and emissions. The use of fossil fuel being one of the main drivers, most modes of transport are looking at alternatives to the limited and environmentally unsustainable fuels. Despite the railway sector being considered the more ‘green’ alternative mode of transport as compared to other modes like air, there exist more work that is required to make the railway sector as efficient and green as possible especially the significant percentage of the railway networks that are still non-electrified. These lines tend to be short, isolated and in some instances with seasonal traffic, hence there not being an urgent need to electrify. The cost of electrification is usually costly especially in terms of initial infrastructure development and alternatives are needed where the cost of electrification is not viable. The main objective of this report is to analyze the current fossil-free alternatives that are available or soon to be available on the market and determine which alternative is suitable for a specific non-electrified line considering factors such as cost, impact to the environment and the long-term strategy. As this is a complex analysis, the authors of this report will utilize the analytical hierarchical process (AHP) model to determine the most suitable choice for each line. The AHP model is one of the multicriteria methods developed to deconstruct complex situations into simple levels with the first level containing the goal: determining the viability of a fossil-free alternative that may be suitable for a particular railway line using the various criteria and sub-criteria. The results differed along the various railway lines with Fryksdalsbanan, Tjustbanan, HällnäsLycksele, Kinnekullebanan and Vaggerydsbanan having battery-operated trains as the optimal choice while the Mellerud-Bengtsfors, Stångådalsbanan, both Inlandsbanan (North and South), HalmstadNässjö, Bockabanan and Nässjö-Vetlanda favoring the hydrogen-fueled trains. In conclusion, both the battery-operated and hydrogen-fueled trains are viable options on the short, low-demand railway lines while the electric trains and diesel-fueled trains are expensive and environmentally unsuitable, respectively.

This thesis considers the problem of hypothesis testing for umbrella alternatives when there are two groups, or strata, of observations. The proposed methods extend a previously established general framework of hypothesis testing based on rankings to stratified datasets by first aligning the strata. The tests based on the Spearman and Kendall distances between ranking vectors lead to the traditional aligned-rank tests and new methods which account for “misalignment” under the alternative hypothesis. Asymptotic null distributions and simulation studies are given for the Spearman distance. Diagnostic tools for the misalignment issue are illustrated alongside the proposed tests on a dataset of IQ scores of coma patients. Extensions to three or more strata and ”adaptive” tests are provided as future research directions.

Les comportements d'autonomie des 164 élèves dont 82 provenaient d'une école alternative et les 82 autres d'une école traditionnelle ont été évalués à l'aide d'un questionnaire jugé valide et fidèle. La démarche visait à étudier l'acquisition de l'autonomie chez les élèves d'une école alternative par rapport à ceux d'une école traditionnelle. Certains facteurs qui ont été considérés dans l'étude sont: l'âge, le sexe et le niveau scolaire des répondants, ainsi que quelques caractéristiques liées à leurs parents comme la scolarité, le revenu et la profession. Les résultats obtenus confirment l'hypothèse générale de recherche qui prédisait que les sujets de l'école alternative possèdent un degré d'autonomie significativement plus élevé que ceux de l'école traditionnelle. La différence significative en faveur des sujets de l'école alternative demeure, que l'on tienne compte ou non de l'âge, du sexe ou du niveau scolaire des répondants. Quelques implications pour le domaine de la recherche et de la pratique courante en éducation sont aussi dégagées. / Québec Université Laval, Bibliothèque 2016

The purpose of this mixed-methods case study was to examine teachers’ beliefs toward in-grade retention in a K-2 school. This study focused on how teachers acquire beliefs regarding grade retention, and their knowledge of research regarding the effectiveness of retention. Witmer, Hoffman and Nottis (2004) contend that teacher beliefs toward grade retention may not be based on research, but on peer influence, past practice, or administrative policy. Quantitative and qualitative data were collected to examine teacher beliefs in a K- 2 school. Quantitative data were collected through the Teacher Opinion Survey (TOS) and Personal Experiences and Retention Practices (PERP). A total of ten K-2 teachers volunteered to complete the survey instruments. Additionally, six K-2 teachers and the school principal were interviewed to collect qualitative data. Data were analyzed to triangulate the findings. This study concluded that teachers continue to retain students as a remedy for academic failure, contrary to what some researchers like Shepard and Smith (1989), who decried that schools were continuing the practice of retention despite research findings that indicated little or no academic achievement is gained though retention. Findings further indicated that teachers disagreed that retention failed to improve achievement, failed to inspire students to buckle down and behave better, and failed to develop students’ social adjustment and self-concept.

No description available.