Thesis advisor: Andrzej Herczynski / The magnetic pendulum investigated in this experiment closely models various forms of the gravitational pendulum. However, the apparatus used in this experiment allows for greater insight as the constant and periodic forces can be easily varied. This project extends the previous work of Sang-Yoon Kim and Francis Moon on the magnetic pendulum by including an additional degree of freedom. This additional degree of freedom allows for a greater understanding of the bifurcation points observed. / Thesis (BS) — Boston College, 2007. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Physics. / Discipline: College Honors Program.

A measurement of the Drell-Yan differential cross section at low invariant mass is presented in the di-muon channel. A 1.64 pb−1 dataset of √s = 7 TeV proton-proton collision data collected by the ATLAS experiment at the LHC is used. The measurement is made in an invariant mass range of 26 < M < 66 GeV where M is the invariant mass of the muon pair. A review of the relevant theoretical physics and the ATLAS detector is made. The analysis is described with particular attention paid to the determination of the isolation efficiency corrections for the Monte Carlo and the estimate of the multijet background. The fiducial differential cross section is calculated with a statistical uncertainty that varies between 0.8% and 1.2%. The systematic uncertainty is seen to vary between 2.4% and 4.1%. A cross section extrapolated to the full phase space is also presented. This is dominated by theoretical uncertainties from the variation of the factorisation and renormalisation scales. The obtained fiducial differential mass cross section is compared to theoretical predictions at NLO and NNLO in perturbative QCD. It is shown that a move beyond NLO is needed to describe the distribution well due to the restrictions of using a fixed order theoretical prediction. A combination with the electron channel measurement is also briefly discussed as well as comparisons to a di-muon measurement in an extended invariant mass range. This allows similar, but stronger conclusions to be drawn. A discussion is made of a PDF fit that uses the measurement presented here. The fit demonstrates the impact of the measurement on the PDFs and further supports the conclusion that a move to NNLO in pQCD is needed to describe the data.

Most financial markets operate as double auction markets in which buyers and sellers submit limit and market orders. In this case the traders have to decide firstly whether they want to submit a buy or sell order and then secondly what the limit price of this order is. In this thesis I develop further a theoretical model based on Chatterjee and Samuelson (1983) in which two traders trade with each other in a double auction market. Assuming that both traders assign a private value to the asset they are trading, which is known only to them but not their trading partner, I determine whether the traders should submit a buy or sell order and what the optimal limit price should be. I develop a single-period model in which traders only trade once and thus cannot learn each other’s private values from trading as well as a multi-period model that allows to infer to some degree the other trader’s private value from their order submission behavior. Using this theoretical model as a benchmark, I then conducted experiments with students to evaluate whether the actual behavior of students fits the theory developed. Although we find that in general the behavior of traders is consistent with the proposed theory, there are some significant differences. Most notably traders seem to underreact to differences in their own private value, i.e. do not adjust their limit price to the extend suggested by theory. I evaluate these outcomes in light of results established results in behavioral finance.

The goal of this thesis is to demonstrate how user testing can be used to identify and remediate learnability issues of a web application. Experimentation revolved around ASSISTments (www.assistments.org), an intelligent tutoring web application in which teachers create virtual classrooms where they can assign problem sets to their students and gain valuable data which can be used to make informed decisions. Recent log analysis uncovered very low task completion rates for new users on tasks that were intended to be trivial. Suspecting that this could be due to poor user interface design, user tests were conducted to help identify usability problems. Sessions were analyzed, and changes were made between each user test to address issues found. Feedback from user testing led to the implementation of an embedded support system. This support system consisted of a splash page which gave an overview of how the system should be used and a collection of context-sensitive tooltips which tried to give the user instructions on what to do as well as explain various parts of the interface. A randomized control trial was performed to measure the effectiveness of the embedded support. 69 participants were shown one of two interfaces: one with embedded support and one without. Task completion rates were analyzed for each of the groups. We found that the support system was able to influence which links a user clicked. However, although the support system was intended to address poor task completion rates, users in the conditions had similar task completion rates regardless of whether the support system was enabled.

This dissertation documents a study of very rare B-meson decays at the LHCb experiment, using data taken during the first experiment run of the Large Hadron Collider (LHC) and during the second experiment run until September 2016. The LHCb experiment was designed to test the Standard Model of particle physics and to search for New Physics effects that go beyond the scope of the Standard Model through the decay of b hadrons produced in high energy proton-proton collisions at the LHC. The measurements described in this dissertation are made using data samples of proton-proton collisions with integrated luminosities of 1.0, 2.0 and 1.4fb⁻¹, collected at centre-of-mass energies of 7, 8 and 13 TeV, respectively. All results are consistent with the predictions of the Standard Model.

The intentional destruction of Bronze Age metalwork prior to deposition is frequently recognised within assemblages, but rarely forms the focus of study. Furthermore, most research focuses on why metalwork was deliberately destroyed without considering how this process was undertaken. This thesis therefore analyses how metalwork might have been intentionally damaged and uses this to better interpret why. The material properties of bronze are considered alongside past research into the use of different implements, before a series of experiments are presented that explore how one might best break a bronze object. A better understanding of the methods by which Bronze Age metalwork might become damaged means one can identify intentional damage over that sustained accidentally, through use or post-deposition. This culminates in a Damage Ranking System, which can be utilised to assess the likelihood that damage observed on archaeological specimens is the result of intent. The Damage Ranking System is applied to Bronze Age metalwork from South West England (i.e. Cornwall, Devon, Dorset and Somerset). The catalogue of metalwork from this region was recently updated, highlighting instances of deliberate destruction that would warrant further study (Knight et al. 2015). The present research builds on this catalogue and involved analysis of complete and damaged objects from across the study region and from throughout the Bronze Age. Approximately 1300 objects were handled and studied and set within the Damage Ranking System alongside a contextual analysis of the findspots. This allowed trends in damage and depositional practices to be observed, demonstrating increased intentional destruction throughout the Bronze Age. It is shown that the deliberate destruction of metalwork throughout the Bronze Age related to the construction of personhood and emphasised links with other regions of Bronze Age Europe. This research demonstrates a new approach to the material that has wide-reaching applications in future studies.

Le confort et la sécurité de conduite sont les principaux critères de vente de l’industrie automobile actuelle. De nombreux projets de recherche sont mis en place afin de les améliorer et pour faire face aux mesures de législation et de contrôle mises en place pour réduire le nombre d’accidents routiers. Les mesures semblent efficaces : en France,par exemple, le nombre des accidents mortels diminue de 11% en moyenne chaque année.D’après de récentes études, 90% de ces accidents ont pour cause le facteur humain et il devient nécessaire de prendre en compte le conducteur pendant la phase de conception des systèmes de sécurité et d’aide à la conduite. Une assistance à la conduite basée sur le partage du contrôle du véhicule entre le conducteur et l’automate est un des axes de recherche privilégiés de l’industrie, notamment pour améliorer la sécurité.Il est maintenant devenu possible de récupérer une très grande quantité d’information sur l’environnement et de réaliser une interaction intelligente entre les différents acteurs du trafic. Les techniques existantes permettent même la conduite partagée entre le véhicule et le conducteur et, dans un horizon plus lointain, d’envisager un véhicule complètement autonome. Dans les situations de conduite automatisée, un algorithme adéquat est nécessaire pour remplacer le conducteur.L’intérêt principal de cette recherche se situe au niveau de l’interaction entre le conducteur et l’algorithme d’assistance ou de conduite automatisée. Il est indispensable de connaître et de comprendre le comportement du conducteur dans sa façon de conduire,de contrôler le véhicule et de prendre une décision. Par conséquent, un modèle adapté aux besoins est nécessaire. En plus de la nécessité de disposer d’un modèle suffisamment riche pour décrire le comportement de différents conducteurs dans les situations routières les plus fréquentes, il est indispensable de disposer d’une méthode de synthèse des systèmes d’assistance sur la base de ces modèles. / Driving comfort and safety are the main points of interest for the automotive industry. Many research projects were realized in order to improve them and to reduce the number of road accidents. The measures seem to be effective : in France, for example, the number of fatal accidents decreases by 11% on average each year. According to recent studies, 90% of these accidents are caused by the human factor. As a consequence, it becomes necessary to take the driver into account during the design of driving assistance systems. An assistance based on the control sharing between the driver and the automatic pilot is one of the main topics of research and a way to improve safety. It has now become possible to recover a very large amount of information on the environment and to achieve intelligent interaction between the various actors in the traffic. Existing technologies even allow imagining a completely autonomous driving in a more distant horizon. In such a situation, an adequate algorithm is required to replace the human driver.The main interest of this research is the interaction between the driver and the driver assistance algorithm. It is essential to know and to understand the behavior of the humanin his / her way to control the vehicle and to make a decision. Therefore, his model is necessary. Moreover, it is essential to develop a design method for such assistance systems on the basis of these driver models.

BakgrundFörskolans arena erbjuder stora möjligheter till naturvetenskapliga upptäckter varje dag. Genom barnens nyfikenhet kan ögonblick fångas upp och bli till rika lärandemiljöer inom området. För att nå dit krävs ett tillåtande klimat där barnen uppmuntras att utforska sin närmiljö. Pedagogens roll är en viktig faktor där produkt och process kan kopplas samman till en meningsfull helhet och på så sätt nå det syfte som verksamheten eftersträvar.SyfteJag vill studera hur förskolebarn agerar, reagerar och resonerar vid utforskandet av naturvetenskapliga experiment, specifikt inriktade på kemi. Mitt intresse riktar sig mot interaktionen och hur den yttrar sig mellan barnen, mellan barnen och det laborativa materialet samt mellan barnen och mig som deltagande observatör.MetodForskningsmetoden har inspirerats utifrån etnografisk ansats, där jag som forskare har valt att vara aktiv på fältet genom att inta rollen som deltagande observatör. Nio barn har medverkat i studien, indelade i tre grupper utifrån respektive förskoleavdelningar. Under laborationerna har jag observerat barnens aktioner och spelat in de samtal som aktiviteten genererat.ResultatResultatet visar en variation i förskolebarns sätt att agera, reagera och resonera vid utforskandet av naturvetenskapliga experiment. Detta synliggörs bland annat genom skillnaden i graden av intensitet hos varje enskilt barn. Gemensamt för alla barn tycks vara deras förmåga att helhjärtat gå in i utforskandet och på så sätt stänga ute intryck från omvärlden. Fantasi, kreativitet och nyfikenhet illustreras som i sin tur visar på hur glädjen infinner sig hos barnen vid utforskandet. / Program: Lärarutbildningen

Ever since Hench et al. first discovered bioactive glass in 1969, extensive interest was created because of the materials ability to chemically bond with living tissue. In this project the bioactivity of three different compositions of the bioactive glass Na2O-CaO-SiO2 have been studied. The compositions of the different glasses were A (25% Na2O, 25% CaO and 50% SiO2), B (22.5% Na2O, 22.5% CaO and 55% SiO2) and C (20% Na2O, 20% CaO and 60% SiO2). Their bioactivity was tested through biomimetic evaluation, in this case by soaking samples of each glass in simulated body fluid (SBF) and phosphate buffered saline (PBS). After soaking, the samples were analyzed with Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), Grazing Incidence X-ray Diffraction (GIXRD) and Fourier-Transform Infrared Spectroscopy (FTIR) to analyze if hydroxyapatite formed on the glass surfaces. Both the A and B glass showed bioactivity in SBF and PBS, while the C glass did not. Further work is necessary to determine which of the A and B glass has the highest apatite formability and the reason why the C glass were not bioactive.

Photocopy of typescript. / Digitized by Kansas Correctional Industries