• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 134
  • 133
  • 38
  • 33
  • 13
  • 11
  • 11
  • 6
  • 5
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • Tagged with
  • 445
  • 88
  • 78
  • 71
  • 60
  • 49
  • 49
  • 38
  • 36
  • 36
  • 33
  • 29
  • 25
  • 24
  • 23
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A political and critical study on the factors that affect Latino enrollment and engagement in advanced placement courses

Marks-Arias, Desirée Elyse 01 February 2013 (has links)
Advanced placement courses are designed to be innovative and rigorous and also encourage and promote critical thinking, communication, and collaboration. Currently, most high schools across the United States offer advanced placement courses with the intent that students enrolled in such courses will be prepared for entering and completing college courses. While advanced placement courses are intended to promote enriched learning experiences for all students, the enrollment of Latino students in high school advanced placement courses is low as compared to other student groups excluding African American students (College Board, 2010). Despite reports, studies, and literature surrounding equity and access in the advanced placement program, research and literature is limited with respect to identifying factors that influence the enrollment in advanced placement courses in high schools from the perspective of Latino students. The purpose of this study was to identify the factors that influence Latino students in their decision to enroll and participate in advanced placement courses in high schools. Moreover, identifying factors that influence enrollment in advanced placement courses from the perspective of the Latino student was critical to analyzing current practice and informing future strategies for increasing enrollment in high school advanced placement courses. This qualitative case study provided rich, descriptive data drawn from student experiences and perceptions from individual interviews that allowed for flexibility and opportunities for further exploration of topics or ideas that emerged from the research to best identify the factors that influence enrollment in advanced placement courses. / text
2

Integration of engineering components into the AP Physics I curriculum

Manuel, Mariam Afzal 07 November 2014 (has links)
This work examines the integration of engineering topics and design in an Advanced Placement (AP) Physics I course as taught in a large urban district in Texas, herein referred to as the school district, and examines whether engineering integrated into physics instruction accomplishes the same educational objectives as dedicated engineering courses such as the Engineer Your World designed by UTeach Engineering Program at The University of Texas at Austin. (Innovative Curriculum for High School Engineering Design, 2013). Observations were conducted in physics classrooms to view the enactment of district prescribed performance tasks. These performance tasks are open-ended, engineering-type challenges involving real-world scenarios in which students generate products. In addition, two AP Physics I instructors from the district were interviewed, one of whom is affiliated with UTeach engineering. A third instructor outside of the district, who teaches physics and Engineer Your World was also interviewed. The findings reported in this work indicate that AP Physics I courses have the potential to include steps of engineering design in traditional physics project-based instruction as well as the opportunity for instructors to utilize engineering-based examples during instruction. However, AP Physics I with its many curriculum requirements and accelerated pace cannot provide an experience comparable to that of an authentic engineering course. A more effective instructional model would be to teach the two courses concurrently, rather than substituting engineering modules in physics courses for an engineering course. To better integrate physics and engineering instruction, professional development geared towards physics teachers interested in incorporating engineering components into their lessons and projects is needed. / text
3

Schémas numériques d'ordre élevé et préservant l'asymptotique pour l'hydrodynamique radiative / High-order asymptotic-preserving numerical scheme for radiation hydrodynamics

Blachère, Florian 27 September 2016 (has links)
Le but de ce travail est de construire un schéma volumes finis explicite d’ordre élevé pour des systèmes de lois de conservation avec terme source qui peuvent dégénérer vers des équations de diffusion sous des conditions de compatibilités. Cette dégénérescence est observée en temps long et/ou lorsque le terme source devient prépondérant. Par exemple, ce comportement peut être observé sur le modèle d’Euler isentropique avec friction, ou sur le modèle M1 pour le transfert radiatif ou encore avec l’hydrodynamique radiative. On propose une théorie générale afin de développer un schéma d’ordre un préservant l’asymptotique (au sens de JIN) pour suivre la dégénérescence. On montre qu’il est stable et consistant sous une condition CFL hyperbolique classique dans le régime de transport comme proche de la diffusion pour tout maillage 2D non structuré. De plus, on justifie qu’il préserve aussi l’ensemble des états admissibles, ce qui est nécessaire pour conserver des solutions physiquement et mathématiquement valides. Cette construction se fait en utilisant le schéma non-linéaire de DRONIOU et LE POTIER pour discrétiser l’équation de diffusion limite. Ensuite, l’extension à l’ordre élevé s’effectue avec des reconstructions polynomiales et la méthode MOOD comme principe de limitation. Les difficultés principales sont la préservation de l’ensemble des états admissibles dans tous les régimes sur maillage 2D non structuré et la préservation de l’asymptotique à tout ordre lors de l’utilisation de reconstructions polynomiales. Des résultats numériques sont présentés pour valider le schéma d’ordre un et d’ordre élevé dans tous les régimes. / The aim of this work is to design a high-order and explicit finite volume scheme for specific systems of conservation laws with source terms. Those systems may degenerate into diffusion equations under some compatibility conditions. The degeneracy is observed with large source term and/or with late-time. For instance, this behaviour can be seen with the isentropic Euler model with friction or with the M1 model for radiative transfer, or with the radiation hydrodynamics model. We propose a general theory to design a first-order asymptotic preserving scheme (in the sense of Jin) to follow this degeneracy. The scheme is proved to be stable and consistent under a classical hyperbolic CFL condition in both hyperbolic and diffusive regimes, for any 2D unstructured mesh. Moreover, we justify that the developed scheme also preserves the set of admissible states in all regimes, which is mandatory to conserve physical solutions. This construction is achieved by using the non-linear scheme of Droniou and Le Potier as a target scheme for the diffusive equation, which gives the form of the global scheme for the complete system of conservation laws. Then, the high-order scheme is constructed with polynomial reconstructions and the MOOD paradigm as a limiter. The main difficulties are the preservation of the set of admissible states in both regimes on unstructured meshes and to deal with the high-order polynomial reconstruction in the diffusive limit without losing the asymptotic preserving property. Numerical results are provided to validate the scheme in all regimes, with the first and high-order versions.
4

Synthesis and Structural Analysis of Nano-size TiO2 via Nanocasting Method

Li, Kuen-ying 25 August 2009 (has links)
TiO2 nanoparticles were successfully synthesized by a wet impregnation method using SBA-15 or AP-SBA-15 as the template for confining the growth of TiO2 nanocrystals followed by acclimation at 550 ¢J in muffle furnace for 6 hrs. These uniform nano-sized TiO2 particles are difficult to prepare using the conventional sol-gel process since the decomposition of the Ti precursor proceeds rapidly to form large aggregates, resulting in a wide particle size distribution. The as-synthesized samples were characterized with powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), and nitrogen adsorption isotherm. Results from TEM reveal that the TiO2 nanoparticles are highly dispersed in the channels of SBA-15; subsequent removal of the SBA-15 channels with HF gives the pure TiO2 nanoparticles having a diameter of ~ 9 nm. On the other hand, the bulk TiO2 outside the SBA-15 channels mainly forms aggregated large TiO2 particles. Prior treatment of SBA-15 surface with the coupling agent APTS (AP-SBA-15) enhances the easy chemosorption of a great number of titanium. Subsequent hydrolysis of the anchored Ti complexes and calcinations of the amorphous TiO2, anatase TiO2 nanocrystals yields uniform TiO2 nanoparticles having diameter of ~ 5 nm, as compared to the unconfined bulk TiO2 of 15~50 nm in diameter.
5

Análise de medidas de velocidade radial na estrela HR1217

Oliveira, Humberto Luz 18 October 2012 (has links)
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Física, Florianópolis, 2001. / Made available in DSpace on 2012-10-18T13:58:22Z (GMT). No. of bitstreams: 1 269711.pdf: 1520115 bytes, checksum: b3a1916cdbe63e3f56ce8c0619f86f38 (MD5) / As estrelas Ap rapidamente oscilante (roAp) são estrelas que mostram muitos modos de oscilações não-radiais. Esses objetos são laboratórios astrofísicos ideais para compreender como e porque estas pulsações ocorrem? Os estudos espectroscópicos das pulsações fornecem informações sobre as propriedades gerais dessa classe de estrelas. Neste trabalho, apresentamos medidas precisas da amplitude da velocidade radial na estrela roAp HR1217 com o telescópio de 2,7m do Observatório McDonald. Essas medidas foram tomadas com uma ampola contendo um gás de Iodo na frente da entrada do espectrógrafo Coudé Echelle de dispersão cruzada. Os resultados das medidas da velocidade radial para cada ordem indicam que a amplitude da pulsação depende da região espectral analisada. Uma análise mais detalhada das medidas individuais das linhas de absorção mostra que os elementos terras raras (Nd e Pr) têm maiores amplitudes de pulsação do que outros elementos (Cr e Fe). Investigamos também a suspeita do comportamento da amplitude com a largura equivalente, reinvidicada por Hatzes e Kanaan e por Baldry. A análise de todas as medidas individuais das linhas não confirmou a suspeita de correlação entre a amplitude de pulsação com a largura equivalente para os três tipos de ajustes: linear, exponencial e constante. Realizamos ainda os mesmos tipos de ajustes para as espécies químicas Nd e Fe, e o melhor ajuste foi o linear, mas a baixa probabilidade deste ajuste P(?2) # 15% não indica uma correlação significativa. Testamos também a hipótese de a amostra das medidas da amplitude ser tendenciosa.
6

An Investigation of Black and Hispanic Participation and Performance in Advanced Placement Courses in a School Division that has Targeted Increased Participation as a Goal

Byrd, Tyrone Qovodis 04 April 2023 (has links)
Participation in Advanced Placement (AP) courses and success on associated exams has become the standard bearer for post-secondary admission. While AP began as a mechanism to support the academic needs of the most advanced students, today it is offered to a diverse range of students. Increasing AP participation and improving AP performance for traditionally underrepresented populations to include Blacks, Hispanics, students with disabilities, and those from lower socioeconomic families has been an ambition of American school districts for the past several decades. This study used AP participation and performance data to investigate the progress one school district has made regarding Black and Hispanic students for the eight school years between 2011-19. Progress was measured by increases in percentages of Black and Hispanic students enrolled in AP courses who sat for an associated AP exam and the percentage of each cohort who earned scores of three or higher on those exams. Significance was determined using Pearson's chi-square and one-way ANOVA tests. Study results show that, among other findings, there was no significant relationship in AP participation for either Black or Hispanic students and that both Black and Hispanic students demonstrated significant improvement in AP performance between school years. / Doctor of Education / The purpose of this study was to identify what change, if any, has occurred in Black and Hispanic AP participation and performance on AP, ACT, SAT, and state mandated reading and writing exams. A quantitative review of Black and Hispanic AP student participation and performance data was conducted to identify areas of significant growth. Participants were identified as Black and Hispanic AP students who sat for an associated exam. Performance data collected and reviewed included Black and Hispanic AP, ACT, SAT, and state mandated reading and writing exam results. Data were collected over an eight-year period and the sample includes all high schools in the school district. The data collected and analyzed for this study identified six findings and six implications. The study was limited by the small sample size of students who fit the profile of having taken and AP course and sitting for an associated exam. Of the nearly thirty-one thousand students considered, less than ten percent were eligible for the study. Considerations for further study includes expanding eligibility to all Black and Hispanic participants regardless of their participation in associated AP exams.
7

Aplinkos veiksnių įtaka organizacijos veiklos gerinimui / Influence of Environmental Factors on the Improvement of Organisation Proceeding

Dovalgaitė, Agnė 16 August 2007 (has links)
Šio darbo tikslas – nustatyti, kokie aplinkos veiksniai veikia organizacijų veiklą bei kokia jų įtaka organizacijos veiklos gerinimui, panaudojant anketas. Magistro darbe yra išanalizuoti ir susisteminti įvairių Lietuvos ir užsienio autorių mokslinės literatūros šaltiniai apie organizacijas, jų vidinę ir išorinę aplinką bei jos svarbą organizacijų veiklai. Apklausti vadovaujamą darbą dirbantys asmenys bei vartotojai. Gauti duomenys apdoroti SPSS programa. Iš dalies patvirtinta hipotezė, jog vadovaujantį darbą dirbantys darbuotojai nepakankamai domisi organizaciją supančia aplinka bei jos įtaka organizacijos veiklai. / The purpose of this work is to identify what environmental factors influence organization’s performance and how they influence the organization’s performance improvement by using the questionnaire forms. Master work analyses and systemizes different Lithuanian and foreign authors’ sources of scholarly literature about the organizations, their internal and external environment and its significance to the organizations’ performance. The author of this work questioned consumers and the managing people. The received data were processed by SPSS program. It partly confirmed the hypothesis that employees performing the managing work don’t show enough interest to the organization‘s performance improvement.
8

Escola pública em Macapa: como, ate quando e porque

Ferreira, Norma Iracema de Barros 18 November 1993 (has links)
Submitted by Beatriz_ Estagiaria (marcianb@ig.com.br) on 2012-01-27T14:49:23Z No. of bitstreams: 1 000060165.pdf: 21849781 bytes, checksum: 65c3952914396ff7c408e32701b86eaa (MD5) / Made available in DSpace on 2012-01-27T14:49:39Z (GMT). No. of bitstreams: 1 000060165.pdf: 21849781 bytes, checksum: 65c3952914396ff7c408e32701b86eaa (MD5) / The quality of the Public School in Macapá justifies its predominance towards the Particular one. Add to that, it has been the kind of institution that attends the school age population. This study analyses the educator’s conception about the importance of preservating the Public School at that city. It also claims to examine the grade of consciousness from that professional about the privilege to have the public education predominating. It is an investigation that aims at calling attention from educators to the importance of their participation redeeming the Public School credibility. / A Escola Pública de Macapá possui uma qualidade que justifica sua prevalência sobre a Particular. Além disso, ela tem sido o tipo de instituição predominante no atendimento da população em idade escolar. O presente estudo analisa a concepção dos educadores macapaenses sobre a importância da preservação da Escola Pública. Procurou-se verificar, também, o grau de consciência destes profissionais sobre o privilégio de usufruir do ensino público. Trata-se de uma pesquisa que visa chamar a atenção dos educadores para a importância de sua participação no resgate da credibilidade da Escola Pública em Macapá.
9

No tempo das águas cheias :: memória e história dos negros do Curiaú - AP /

Trindade, Joseline Simone Barreto. January 1999 (has links)
Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro de Filosofia e Ciências Humanas. / Made available in DSpace on 2012-10-18T23:36:21Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-09T02:19:36Z : No. of bitstreams: 1 151990.pdf: 100538026 bytes, checksum: ff28ddeff88c3e95c8f919304c90da31 (MD5)
10

Etude du rôle des sites de liaison AP-1 intragéniques dans la régulation de l'expression du HIV-1 (Human Immunodeficiency Virus type 1)

Vandenhoudt, Nathalie 26 June 2009 (has links)
La vitesse de réplication du HIV-1(Human Immunodeficiency Virus type 1), qui semble corrélée de manière directe à la vitesse de progression de la maladie vers le stade SIDA, est essentiellement contrôlée au niveau transcriptionnel. La transcription du HIV-1 est régulée par la structure chromatinienne, des éléments agissant en cis localisés dans les LTRs, des facteurs de transcription agissant en trans et par la protéine virale trans-activatrice Tat (revu dans Quivy et al. 2007, Bisgrove et al. 2005, Rohr et al. 2003, Rabson and Graves 1997). En plus de l’enhancer localisé dans le LTR5’ du HIV-1, un enhancer intragénique, localisé dans le gène pol du HIV-1, inductible par le phorbol 12-myristate 13-acétate (PMA) a été identifié. La localisation progressive de l’activité enhancer a permis de définir deux domaines distincts et indépendants dans cet enhancer intragénique : les fragments 5103 et 5105 localisés respectivement dans la partie centrale du gène pol et dans une région couvrant la fin du gène pol, le gène vif, le gène vpr et le premier exon codant des gènes tat et rev (Verdin et al. 1990). Les fragments 5103 et 5105 se comportent tous deux comme des enhancers inductibles par le PMA lorsqu’ils sont clonés en amont du promoteur de la thymidine kinase dans un vecteur rapporteur en cellules HeLa. Notre laboratoire a précédemment identifié trois sites de liaison pour les facteurs de transcription AP-1 dans le fragment 5103 (Van Lint et al., 1991). Au cours de notre thèse, nous avons poursuivi la caractérisation de ces sites de liaison AP-1 et avons montré que les facteurs c Fos, JunB et JunD interagissent in vitro avec ces motifs. Pour chaque site, nous avons identifié des mutations qui abolissent la liaison des facteurs AP-1 sans altérer la séquence en acides aminés sous-jacente de la transcriptase inverse. Par des expériences de transfection transitoire, nous avons démontré que les sites AP 1 intragéniques sont entièrement responsables de l’activité enhancer PMA-dépendante du fragment 5103. De plus, l’activité PMA-inductible du fragment 5103 est inhibée par le mutant dominant négatif A-Fos à condition que les sites ne soient pas mutés. A l’inverse, l’expression ectopique de dimères forcés AP-1 affecte positivement l’activité enhancer du fragment 5103. Enfin, nous avons étudié le rôle biologique des sites AP-1 intragéniques dans la réplication virale et avons montré que ces sites contribuent positivement à l’infectivité du virus. Durant la seconde partie de notre thèse, nous avons entamé la caractérisation physique et fonctionnelle du fragment 5105. Nos résultats de transfection transitoire montrent que l’activité PMA inductible du fragment 5105 est localisée dans le dernier tiers de ce dernier : le sous fragment 5105.3. L’analyse bioinformatique de cette région a permis de mettre en évidence un site de liaison pour les facteurs AP-1 in vitro. Des mutations ponctuelles permettent d’abolir la liaison des facteurs à leur site mais altèrent la séquence en acides aminés sous-jacente codant pour les protéines Tat et Rev. Nous avons montré que ce site est impliqué dans l’activité transcriptionnelle de ce fragment. L’expression ectopique du mutant dominant négatif A-Fos inhibe l’activité transcriptionnelle PMA-inductible du fragment 5105. Une analyse bioinformatique plus large nous a ensuite permis d’identifier in vitro, par retard de migration sur gel, 5 sites de liaison pour le facteur YY1 et 2 sites de liaison pour le facteur PU.1 dont les implications pour le virus restent encore à déterminer.

Page generated in 0.0233 seconds