En 2007 aura lieu au CERN le démarrage du collisionneur LHC qui étudiera l'origine de la masse et cherchera les signes d'une nouvelle physique. L'expérience ATLAS en exploitera les potentialités avec un détecteur généraliste multicouches.<br />L'étude du quark top sera une étape importante : ses propriétés peuvent révéler une éventuelle nouvelle physique. Dans ce but, la polarisation du quark top et du boson W ont été étudiées avec une simulation détaillée du détecteur, dont les résultats confirment la simulation simplifiée. Ils indiquent une précision de 1 à 7 % avec 10 fb-1 de données, adéquate pour écarter ou retenir divers modèles de nouvelle physique.<br />Le calorimètre électromagnétique d'ATLAS est crucial pour l'observation des électrons et photons, et donc pour la recherche du boson de Higgs. Sa mise en route est illustrée ici par l'analyse des rampes reliant le calibrage au signal mesuré, ainsi qu'une analyse des muons cosmiques, premier test de la chaîne de lecture dans de vraies conditions de fonctionnement.

Block copolymers (BCPs) are an attractive alternative for patterning applications used to produce next-generation microelectronic devices. Advancements require the development of high interaction parameter χ BCPs that enable patterning at the sub-10 nm length scale. Several organosilicon BCPs were designed to both enhance χ and impart an inherent etch selectivity that facilitates pattern transfer processes. Increasing the BCP silicon content both increases χ and bolsters the etch resistance, providing a pathway to designing new high-χ materials. Unfortunately, the BCPs investigated are not amenable to thermal annealing because the organosilicon block preferentially segregates to an air/vacuum interface and drives orientation parallel to the surface. A series of spin-coatable, polarity-switching top coats (as well as other strategies) were developed to provide a “neutral” top interface and promote the perpendicular orientation of BCP domains. In addition, a methodology for evaluating the neutral condition, relying on thickness quantization and the corresponding wetting behavior (i.e. island/hole topography) of lamellae. The top coat strategy was demonstrated for several BCP systems, and perpendicular structures can successfully be etched on commercial tools and be transferred into underlying substrates. The interaction parameter χ was evaluated using two methods to compare the performance of several BCPs: the order-disorder transition (ODT) of symmetric diblock copolymers, and the absolute scattering profile of a disordered BCP melt. Both methods, while severely limited for quantitative comparison, indicate trends towards higher χ with additional appended polar and organosilicon functional groups. Furthermore, the pattern fidelity is shown to be a function of the overall BCP segregation strength. The free energy of confined lamella was modeled algebraically to produce response surface plots capable of identifying process conditions favorable for perpendicular orientation. Thickness independent perpendicular orientation is only favorable using two neutral interfaces. Incommensurate film thicknesses are the most favorable, with commensurability conditions dependent on the wetting behavior at each interface. The modeling was supplemented with an extensive body of thin film experimental work that qualitatively agrees well with the above conclusions.

Background Research has shown that people need to be pre-informed about the ambiguity in order to perceive both interpretations (reverse) of an ambiguous figure. Children younger than 4 years mostly do not experience reversal even when informed. This suggests that the processes involved in reversal develop at this age. Aim The aim of the studies reported here was to disentangle the cognitive processes (metarepresentation, executive function, mental imagery) and the role of eye-movements involved in reversal. Method Four studies (7 experiments), each involving around sixty 3-, 4- and 5-year-old children, using multiple tasks, were conducted. The primary tasks used were the Ambiguous Figures Production and Reversal tasks. The secondary tasks used were metacognitive, executive function and mental imagery tasks. New tasks were also implemented in order to assess reversal abilities. Results Between the ages of 3 and 4 children develop the basic conceptual understanding for reversal (Study 1), that an ambiguous figure can have two interpretations. This is associated with the understanding of false belief, synonymy and homonymy. Between the ages of 4 and 5 children develop inhibitory (Study 3) and image generation abilities (Study 4). These are key cognitive processes necessary for reversal. Contrary to previous research, when task demands were changed (Reversal Task Revised) children’s reversal is at ceiling by the age of 5 (Studies 3 and 4). Eye-tracking data suggests that appropriate eye-movements, focusing on particular parts of the ambiguous figure, are not a primary causal factor in the development of reversal abilities (Study 4). Conclusion The ability to reverse develops in two stages. During stage 1 (between 3 and 4 years) children develop the necessary conceptual understanding that an ambiguous figure can have two interpretations (top-down knowledge). During stage 2 (between 4 and 5 years) children develop the necessary cognitive processes for reversal to occur (inhibition and image generation).

Although much has been written about the challenges affecting transfer students, a mixed method study on transfer admission, particularly at the institutional level is an intriguing, albeit unexplored endeavor. In Texas, there is an added dimension of interest given the presence and popularity of the Top 10% Law. This study sought to provide a comprehensive portrait of transfer admission at The University of Texas at Austin from the 1990s to 2007. A sequential explanatory design was employed to identify changes in transfer admission policy and practice and to address if there were differences in admission rates among the major transfer pathways to the state’s largest flagship institution (Creswell, Plano Clark, Gutmann, & Hanson, 2003). Two main conclusions emerged from this study. First, transfer admission became more competitive and selective after the passage of the state’s Top 10% Law in 1997. Second, qualitative and quantitative findings suggested the implementation of a conditional transfer guarantee program for highly selective freshman applicants resulted in significantly less opportunity for transfer applicants from community colleges and other transfer routes to be admitted. Based on these findings, recommendations included reinvesting in a community college transfer student recruitment and scholarship program and significantly reducing the size of the university’s conditional transfer guarantee program for admissible freshmen applicants. A final suggestion was to identify and value the community college route in the holistic transfer admission process given the large proportion of first-generation college, low-income students who comprise this population. To avoid perceptions of sponsored mobility and to promote a social justice rationale, a pre-selection transfer program to prospective freshmen should be revisited given the adverse effects on the community college transfer population. With over 600,000 students enrolled in Texas 2-year colleges, a viable pathway to the state’s most prestigious flagship university provides increased opportunities for social mobility to the many competitively admissible first-generation and low-income students populating public 2-year colleges and seeking a baccalaureate degree from UT Austin. / text

Tyrimo objektas. Sportinę karjerą baigusių sportininkų socialinio aprūpinimo ypatumai Lietuvoje. Tyrimo tikslas: atskleisti sportinę karjerą baigusių sportininkų socialinio aprūpinimo ypatumus Lietuvoje. Tyrimo uždaviniai: 1 Teoriniu aspektu aptarti profesionalaus ir didelio meistriškumo sportininkų sampratą ir jų teisinį reglamentavimą Lietuvoje. 2. Išanalizuoti teisės aktus, reglamentuojančius sportinę karjerą baigusių sportininkų socialinio aprūpinimą Lietuvoje. 3. Palyginti teisės aktus, reglamentuojančius sportinę karjerą baigusių sportininkų socialinį aprūpinimą su Europos šalių patirtimi. 4. Įvertinti sportinę karjerą baigusių Lietuvos profesionalių ir didelio meistriškumo sportininkų nuomonę apie jiems teikiamas socialines garantijas. Tyrimo metodai. 1. Literatūros šaltinių analizė. 2. Dokumentų analizė. 3. Interviu. Tyrimo rezultatai. Profesionalusis sportininkas apibrėžiamas kaip sportininkas, kurio pagrindinis pragyvenimo šaltinis ir darbas yra sportavimas. Didelio meistriškumo sportininkas apibrėžiamas kaip atletas, atstovaujamos sporto šakos vienas geriausių sportininkų. Profesionalus ir didelio meistriškumo sportininko teisinis statusas reglamentuojamas LR Kūno kultūros ir sporto įstatyme. Literatūros šaltinių ir dokumentų analizė parodė, kad karjerą baigusių sportininkų socialinis aprūpinimas Lietuvoje yra reglamentuojamas LR valstybinio socialinio draudimo įstatymu, LR valstybinių socialinio draudimo pensijų įstatymu bei naująja LR kūno kultūros ir sporto... [toliau žr. visą tekstą] / Work object: Peculiarities of social provision of former athletes in Lithuania Work objectives: to analyze the peculiarities of social provision of former athletes in Lithuania Work objectives: 1. To discus the conception and juridical regulation of professional and top level athlete in Lithuania. 2. To analyze juridical documents that regulates social provision of retired athletes in Lithuania 3. To compare juridical documents, that regulates social provision of retired athletes in Lithuania with present experience of European countries. 4. To evaluate opinion of retired professional and top level athletes about present social guaranties that is provided. Work Methods. 1. Analysis of literature sources. 2. Document analysis. 3. Interview. Conclusions. Professional athlete is defined as a person who receives payment for his performance and earns for living in that way. Whereas Top level athlete can be described as an athlete that competes at the highest level, represents country during international events. The status of Professional and Top Level Athlete is regulated by the Law of Sport and Physical Education. Literature and Documents analysis proved that Social Provision of retired athletes in Lithuania is regulated by the Lithuanian Republic Law of Social Security, LR National Law of Social Provision and by the Law of Sport and Physical Education. Retired athletes can attain social guaranties if they succeed during the active career to become a medallist of one oft top... [to full text]

The Madden-Julian Oscillation (MJO), a tropical phenomenon that exists on the time scale of 30-90 days, commonly initiates over the Indian Ocean and slowly propagates into the western Pacific as a series of convective events, which have time scales on the order of hours or days. These events and the overall MJO convective envelope may interact with convectively coupled waves such as Kelvin waves that propagate more rapidly eastward with time scales of 3-5 days. Radar and sounding data collected during the DYNAMO/AMIE/CINDY2011 field campaign from October 2011 to February 2012 in the central Indian Ocean are used to study the interaction between Kelvin waves and the MJO in terms of atmospheric and cloud properties. The focus is on characterizing the precipitation characteristics, convective cloud spectrum, and atmospheric profiles of Kelvin waves during the active and suppressed phases of the MJO to gain insight on MJO initiation. Characteristics of waves identified using different satellite thresholds and filtering methods are compared. Composites of the radar and sounding observations are calculated for a total of ten Kelvin waves and three MJO events that occurred during the field campaign. Analyzed radar products include convective-stratiform classification of rain rate, rain area, and echo-top heights, as well as cloud boundaries. Sounding data includes profiles of wind speed and direction and relative humidity. Kelvin waves that occur during the suppressed MJO are convectively weaker than Kelvin waves during the active MJO, but display previously documented structure of low-level convergence and a moist atmosphere prior to the wave passage. During the active MJO, Kelvin waves have stronger convective and stratiform rain, and the entire event is longer, suggesting a slower moving wave. The Kelvin wave vertical structure is somewhat overwhelmed by the convective envelope associated with the MJO. When the MJO is developing, the Kelvin wave displays a moisture-rich environment after the passage, providing deep tropospheric moisture that is postulated to be important for the onset of the MJO. The convective cloud population prior to MJO initiation shows increased moisture and a population of low- to mid-level clouds. The moisture precedes shallow convection, which develops into the deep convection of the MJO, supporting the discharge-recharge theory of MJO initiation. Additionally, enhanced moisture after the passage of the pre-MJO Kelvin wave could also support the frictional Kelvin-Rossby wave-CISK theory of MJO initiation. With a better understanding of the interaction between the initiation of the MJO and Kelvin waves, the relationships between the environment and the onset of the convection of the MJO can be improved.

Fund investments are very popular in Sweden. However, we have the impression that despite this popularity, the average fund investor in Sweden does not pay much attention to the importance and possible link of fund’s asset composition features (e.g. Asset class, Holdings, and Geo-exposure) to fund’s performance. Instead, S/he relies on factors such as fees, risk levels, historical performance, etc. in her/his investment decisions. Similarly, academic studies mainly focus on attributes such as funds fees, size, and manager’s skill to explain fund’s performance. Thus there are limited premier academic studies on the relationship between fund’s performance and its asset composition features. The main purpose of this study is to investigate possible causal relationship between the performances of funds with their assets composition features. We study the whole population of 346 Swedish listed mutual funds older than five years for the period 2009-2013. The results of the study provides the investors and analysts with additional decision-making and investment-analysis tools to assist them in making more informed judgment on funds and their expected returns. The results are also useful for fund managers to improve their strategies by refining the combinations of their funds’ asset composition attributes in order to improve the absolute risk-adjusted performance of their funds. Our research philosophy has been based on positivism and objectivism along with functionalist paradigm and we have applied deductive approach to test the theories. We have used quantitative method and collected the funds’ data from public business databases and chosen Jensen’s alpha and Treynor ratio as funds’ risk-adjusted performance measures. We performed Correlation tests and Regression with robust techniques on our data to answer the research question from three aspects, namely asset class (equity, bond, and mixed assets); geo-exposures (Sweden, Global, Europe, and Nordic) and Top-ten holdings’ measures (asset concentration and Treynor of each fund’s passive top-ten sub-portfolio). We conclude that correlations between funds’ risk-adjusted performance and assets composition features are likely to exist. Stronger correlations are observed between the explanatory measures and fund’s relative risk-adjusted performance (fund’s Treynor) as compared to fund’s absolute risk adjusted performance (fund’s Jensen’s alpha). Asset concentration in top-ten holdings and bond asset class are more likely to be in casual relationship with fund’s risk-adjusted performance, whereas Treynor ratio of top-ten holdings’ passive sub-portfolio as well as fund’s geo-exposure do not seem to have strong explanatory power for funds’ absolute performance.

Deux analyses de physique des particules à hautes énergies sont présentées dans ce manuscrit de thèse, utilisant des événements avec deux leptons de charges opposées et de l'énergie transverse manquante. Ces événements sont sélectionnés parmi 9.7 fb-1 de données totales de collisions pp enregistrées par le détecteur DØ auprès du collisionneur TeVatron du Fermilab à √s=1.96 TeV.La première analyse est la recherche du boson de Higgs se désintégrant en H→WW→μνμν. Aucun excès significatif au-dessus de l'attente pour le bruit de fond n'est observé.Des limites supérieures sur la section efficace de production du boson de Higgs sont donc calculées dans le cadre du modèle standard mais aussi dans l'hypothèse de l'existence d'une quatrième génération de fermions et dans le contexte de couplages fermiophobiques du boson de Higgs.Pour valider la méthodologie de cette recherche, la section efficace de production de la paire de bosons W est mesurée.La seconde analyse est la mesure de l'asymétrie avant-arrière de production de la paire tt. Il s'agit de la première mesure dans le canal dileptonique de l'expérience DØ. Dans ce contexte, une méthode inédite de reconstruction de la cinématique de la paire est utilisée (méthode des éléments de matrice) pour donner une mesure brute de l'asymétrie avant-arrière. A l'aide d'une méthode de calibration dédiée, nous donnons une mesure finale de AFB=18.0 ± 6.0 (stat) ± 3.3 (syst).

L'objectif principal de cette thèse est de fournir une mesure aussi précise que possible de la masse du quark top dans son canal de désintégration semi-leptonique. Cette mesure expérimentale est réalisée à l'aide du détecteur ATLAS, installé auprès du LHC, un collisionneur proton-proton. Les motivations principales à cette mesure de précision sont les contraintes qu'elle apporte aux modèles de physique. Par ailleurs, la masse du quark top est un paramètre permettant d'estimer l'état de stabilité du vide dans le cadre du Modèle Standard, à l'échelle de Planck. Les jets sont des objets dont l'étalonnage en énergie est cruciale pour la mesure. Une étude détaillée de cette calibration est présentée, et notamment l'impact des conditions réelles de prises de données sur la performance de ces objets. La mesure de masse utilisant les données prises en 2011 à une énergie dans le centre de masse de 7 TeV est détaillée. Cette mesure utilise une méthode d'analyse particulière, appelée méthode des templates tridimensionnels. La masse du quark top mesurée est: mtop = 172.01 ± 0.92 (stat) ± 1.17 (syst) GeV. Les données prises en 2012 à une énergie dans le centre de masse de 8 TeV sont aussi analysées, et une mesure préliminaire de la masse du quark top est fournie: mtop = 172.82 ± 0.39 (stat) ± 1.12 (syst) GeV, la combinaison des deux mesures donnant le résultat le plus précis de cette thèse: mtop = 172.64 ± 0.37 (stat) ± 1.10 (syst) GeV.

La première partie rapporte la caractérisation de prototypes de chambre MICROMEGAS en tests sous faisceaux et en laboratoire. L'étude détaille notamment l'efficacité de détection, la multiplicité de la réponse et dépendance du gain du détecteur vis à vis des conditions environnementales. Dans la seconde partie, La détection d'un boson de jauge Z', prédit par différends modèles de types Randal-Sundrum est étudiées dans le cadre de l'expérience CLIC. Le canal considéré implique l'émission du Z' par une paire de quarks top. Le Z' se désintègre ensuite en particules de matière noire.