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  • 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.
301

The Dark Triad and Faking Ability on Self-Report Personality Inventories and Autobiographical Accounts

MacNeil, Bonnie 21 October 2008 (has links)
Three studies were undertaken to examine the relationship between the Dark Triad (i.e., psychopathy, Machiavellianism, and narcissism) and faking ability. Study 1 examined the relationship between psychopathy and the ability to fake good and fake bad on self-report personality inventories in a sample of 84 male federal offenders. Results showed that when faking good, successful fakers scored significantly higher than unsuccessful fakers on carefree nonplanfulness, and significantly lower on stress immunity. When faking bad, successful and unsuccessful fakers did not differ significantly on psychopathy total or subscale scores. Study 2 examined the effect of the Dark Triad on the ability to fake good and fake bad on self-report personality inventories in a sample of 166 undergraduates. Results indicated that when faking good, total psychopathy significantly predicted successful faking for 1 of 3 methods of evaluation, while Machiavellianism significantly predicted success at faking good for 2 of 3 methods of evaluation. Narcissism was unrelated to success at faking good. In addition, the Dark Triad constructs did not predict success at faking bad. Study 3 examined the relationship between the Dark Triad constructs and the ability to fake good interpersonally. In this study, 32 undergraduates comprising four groups (i.e., controls, and individuals high in psychopathy, Machiavellianism, and narcissism) provided videotaped self-presentations. A separate group of 134 university students subsequently rated the veracity of these presentations. Results indicated that when faking good, psychopathy and narcissism groups were rated as more believable than the control group. Conversely, the Machiavellianism group was less successful at faking good than the control group. Contributions of this research to the fields of personality assessment and self-presentation are discussed. / Thesis (Ph.D, Psychology) -- Queen's University, 2008-10-14 11:24:45.946
302

PERFORMANCE EVALUATION OF SIGNAL CONDITIONING BOARDS AND SIMULATION OF THE IMPACT OF ELECTRONICS NOISE ON THE DEAP-3600 DARK MATTER DETECTOR

Chouinard, Rhys Timon Unknown Date
No description available.
303

Kaluza Klein Dark Matter Analysis with the AMANDA Neutrino Telescope

Han, Kahae January 2010 (has links)
In this work the search for the dark matter arising from a model of extra dimensions, otherwise known as Kaluza Klein WIMPs, on the data taken with the AMANDA neutrino telescope in the South Pole is presented. The limit on the dark matter from the Kaluza Klein Solar WIMPs analysis on the data taken from year 2001 to 2003 is derived.
304

Supersymmetric Dark Matter in IceCube

Silverwood, Hamish George Miles January 2012 (has links)
The Minimally Supersymmetric Standard Model (MSSM) provides us with a WIMP dark matter candidate particle, the neutralino. Neutralinos from the dark matter halo can potentially become captured by the sun and concentrated in the core, where they can undergo self-annihilation and so produce a distinct neutrino signal. The IceCube Neutrino Observatory has the potential to detect this neutrino signal and thus give indirect evidence of the presence and properties of neutralino dark matter. Although the full, unconstrained MSSM has 105 parameters this can be reduced to 25 parameters by the application of physically motivated assumptions. Scans of this MSSM-25 parameter space are conducted using the DarkSUSY software package and an adaptive scanning technique based on the Monte-Carlo VEGAS algorithm. The IceCube exclusion confidence level is then calculated for a set of points produced by these scans. Results indicate that the detection capability of IceCube exceeds that of current direct detection methods in certain regions of the parameter space. The use of a 25 dimensional parameter space reveals that there are new regions of observables with high exclusion confidence levels compared to earlier simulations performed with a seven dimensional parameter space.
305

Symmetries of Elko and massive vector fields

Lee, Cheng-Yang January 2012 (has links)
This thesis studies the symmetries and phenomenologies of the massive vector fields of indefinite spin with both scalar and spin-one degrees of freedom and Elko. The investigation is conducted by using and extending the quantum field theory formalism developed by Wigner and Weinberg. In particular, we explore the possibility that the W± and Z bosons have an additional scalar degree of freedom and show that Elko is a fermionic dark matter candidate. We show that the massive vector fields of indefinite spin are consistent with Poincaré symmetry and have physically desirable properties that are absent for their pure spin-one counterpart. Using the new vector fields, the decay of the W± and Z bosons to leptons at tree-level are in agreement with the Standard Model (SM) predictions. For higher order scattering amplitudes, the theory has better convergent behaviour than the intermediate vector boson model and the Fermi theory. Elko has the unusual property that it satisfies the Klein-Gordon but not the Dirac equation and has mass dimension one instead of three-half. We show that the Elko fields are local only along a preferred axis and that they violate Lorentz symmetry. Motivated by the results obtained by Ahluwalia and Horvath that the Elko spin-sums are covariant under very special relativity (VSR) transformations, we derive the VSR particle states and quantum fields. We show that the VSR particles can only interact with the SM particles through gravity and massive scalar particles thus making them and hence Elko dark matter candidates.
306

Astrophysical Constraints on Dark Matter

Macias Ramirez, Oscar January 2014 (has links)
Well motivated theoretical models predict the annihilation of dark matter (DM) into standard model particles, a phenomenon which could be a significant source of photons in the gamma-ray sky. With its unprecedented sensitivity and its broad energy range (20 MeV to more than 300 GeV) the main instrument on board the Fermi satellite, the Large Area Telescope (LAT), might be able to detect an indirect signature of DM annihilations. In this work we revisit several interesting claims of extended dark matter emission made from analyses of Fermi-LAT data: First, based on three years of Fermi Large Area Telescope (LAT) gamma-ray data of the Virgo cluster, evidence for an extended emission associated with dark matter pair annihilation in the bb̄ channel has been reported by Han et al. (arxiv:1201.1003). After an in depth spatial and temporal analysis, we argue that the tentative evidence for a gamma-ray excess from the Virgo cluster is mainly due to the appearance of a population of previously unresolved gamma-ray point sources in the region of interest. These point sources are not part of the LAT second source catalogue (2FGL), but are found to be above the standard detection significance threshold when three or more years of LAT data is included. Second, we confirm the detection of a spatially extended excess of 2-5 GeV gamma rays from the Galactic Center (GC), consistent with the emission expected from annihilating dark matter or an unresolved population of about 10³ milisecond pulsars. However, there are significant uncertainties in the diffuse galactic background at the GC. We have performed a revaluation of these two models for the extended gamma ray source at the GC by accounting for the systematic uncertainties of the Galactic diffuse emission model. We also marginalize over point source and diffuse background parameters in the region of interest. We show that the excess emission is significantly more extended than a point source. We find that the DM (or pulsars population) signal is larger than the systematic errors and therefore proceed to determine the sectors of parameter space that provide an acceptable fit to the data. We found that a population of order a 10³ MSPs with parameters consistent with the average spectral shape of Fermi-LAT measured MSPs was able to fit the GC excess emission. For DM, we found that a pure τ⁺τ⁻ annihilation channel is not a good fit to the data. But a mixture of τ⁻τ⁻ and bb̄ with a (σν) of order the thermal relic value and a DM mass of around 20 to 60 GeV provides an adequate fit. We also consider the possibility that the GeV excess is due to nonthermal bremsstrahlung produced by a population of electrons interacting with neutral gas in molecular clouds. The millisecond pulsars and dark matter alternatives have spatial templates well fitted by the square of a generalized Navarro-Frenk-White (NFW) profile with inner slope γ = 1.2. We model the third option with a 20-cm continuum emission Galactic Ridge template. A template based on the HESS residuals is shown to give similar results. The gamma-ray excess is found to be best fit by a combination of the generalized NFW squared template and a Galactic Ridge template. We also find the spectra of each template is not significantly affected in the combined fit and is consistent with previous single template fits. That is, the generalized NFW squared spectrum can be fit by either of order 10³ unresolved MSPs or DM with mass around 30 GeV, a thermal cross section, and mainly annihilating to bb̄ quarks. While the Galactic Ridge continues to have a spectrum consistent with a population of nonthermal electrons whose spectrum also provides a good fit to synchrotron emission measurements. We also show that the current DM fit may be hard to test, even with 10 years of Fermi-LAT data, especially if there is a mixture of DM and MSPs contributing to the signal, in which case the implied DM cross section will be suppressed.
307

An Exploration into the Use of the Biblical Narrative of the Fall within the children’s series The Chronicles of Narnia by C.S. Lewis and His Dark Materials by Philip Pullman

Fisher, Rebecca Maree January 2008 (has links)
In this thesis, I explore the uses to which children’s authors C.S. Lewis and Philip Pullman put the major biblical theme of the Fall (with passing commentary on Temptation, the precursor to the Fall) in their seminal children’s series The Chronicles of Narnia and the His Dark Materials trilogy. I argue that each author uses the subject of the Fall as a central theme in his series in order to inflect the dominant message of this biblical story (that humanity has fallen from perfection into sin) with their personal opinions on fundamental human questions concerning the nature of God, the difference between good and evil, and the metaphysical ‘rules’ that structure the universe and mankind’s place in it.1 In exploring these issues, I point out the ways in which Pullman and Lewis, in their drastically differing opinions as to the legitimacy of the worldview implicit in the original Bible story, are nevertheless both heavily dependant on the overwhelming influence that the Fall narrative has had on Western culture.
308

Recreation of the Bullet Cluster (1E 0657-56) merging event via N-body computer simulation

Balint, Zsolt T. 21 July 2012 (has links)
In this study I present two N-body computer simulations of the Bullet Cluster (1E 0657-56) merging system. The models are fully self-consistent, meaning that all gravitational forces are determined by the distribution of the particles. Initial positions and velocities of the two clusters are determined by solving a two-body problem. Post-collision time period shows an increase in the line-of-sight velocity dispersion in both clusters, and is consistent with previous Bullet Cluster studies. I also investigate the temporal evolution of the average cluster radial velocities of the galaxies located in the inner, middle, and outer regions of the clusters. I show that the orbital trajectories differ in pre- and post-collision periods. Inner region galaxies receive an impulse that moves them outward from the cluster center immediately after collision, while at the same time the outer region galaxies are pulled back towards the cluster center. / Department of Physics and Astronomy
309

Dark Ages Lunar Interferometer : Deployment Rover - Suspension System and Transition Mecanism

Pasalic, Haris, Bernfort, Björn January 2014 (has links)
This thesis is a continuation of last year's work and it builds on earlier construction of a rover that will deploy an interferometer on the far side of the moon. The project is done in collaboration with (JPL) Jet Propulsion Laboratoryin Pasadena, California. Given the size of the mission, accuracy and time limit project has been split into several smaller projects. The areas that are the focus of this project are the suspension and the transition system. The transition system that is originated from the stage when the rover transforms from the transit mode to ready mode, and the suspension system, are in this thesis work presented by detailed conceptual design. The next step, not mentioned this thesis work, will be to perform aprimary structure design on the details. The project owner’s ultimate goal is to create a better understanding about the origins of the universe and its continual changing. This would give scientists an opportunity to study some of the most fundamental questions that are still are waiting for answers. Together with a group of energy engineers, Gustav Andersson and Emil Ericsson, we were caught by the very attractive project assignment, well aware that not many people get the chance or the opportunity to be involved or work with projects like this.
310

The Milky Way's dwarf satellite galaxies in [L]CDM: orbital ellipticities and internal structure

Barber, Christopher 01 May 2014 (has links)
Current models of cosmology and galaxy formation are possibly at odds with observations of small-scale galaxies. Such is the case for the dwarf spheroidal (dSph) galaxies of the Milky Way (MW), where tension exists in explaining their observed abundance, mass, and internal structure. Here we present an analysis of the substructure surrounding MW-sized haloes in a Lambda Cold Dark Matter (LCDM) simulation suite. Combined with a semi-analytic model of galaxy formation and evolution, we identify substructures that are expected to host dSph galaxies similar to the satellites of the MW. We subsequently use these simulations to investigate the orbital properties of dSph satellite galaxies to make contact with those orbiting the MW. After accretion into the main halo, the higher mass ``luminous'' substructure remains on highly radial orbits while the orbits of lower mass substructure, which are not expected to host stars, tend to scatter off of the luminous substructure, and thus circularize over time. The orbital ellipticity distribution of the luminous substructure shows little dependence on the mass or formation history of the main halo, making this distribution a robust prediction of LCDM. Through comparison with the ellipticity distribution computed from the positions and velocities of the nine MW dSph galaxies that currently have proper motion estimates as a function of the assumed MW mass, we present a novel means of estimating the virial mass of the Milky Way. The best match is obtained assuming a mass of 1.1 x 10^12 M_sun with 95 per cent confidence limits of (0.6 - 3.1) x 10^12 M_sun. The uncertainty in this estimate is dominated by the large uncertainties in the proper motions and small number of MW satellites used, and will improve significantly with better proper motion measurements from Gaia. We also measure the shape of the gravitational potential of subhaloes likely to host dSphs, down to radii comparable to the half-light radii of MW dSphs. Field haloes are triaxial in general, while satellite haloes become more spherical over time due to tidal interactions with the host. Thus through the determination of the shape of a MW dSph's gravitational potential via line of sight velocity measurements, one could in principle deduce the impact of past tidal interactions with the MW, and thus determine its dynamical history. Additionally, luminous subhaloes experience a radial alignment of their major axes with the direction to the host halo over time, caused by tidal torquing with the host's gravitational potential during close pericentric passages. This effect is seen at all radii, even down to the half-light radii of the satellites. Radial alignment must be taken into account when calibrating weak-lensing surveys which often assume isotropic orientations of satellite galaxies surrounding host galaxies and clusters. / Graduate / 0606

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