<p>The dark focus is a resting state of accommodation, which occurs when there are not enough stimuli for the eye to focus on. This means that the eye becomes more myopic and some people notice a blur for example at night time, more known as night myopia. In this study the dark focus in Swedish myopes is measured and any difference between early and late onset myopes is investigated.</p><p><strong>Method: </strong>The dominant eye of 56 myopes was first measured with static retinoscopy, using a distant target, and then with near retinoscopy, with the retinoscope beam as the target. The full working distance of 2.00 D was subtracted in both methods and the values were compared. The difference, if any, was the dark focus.</p><p><strong>Results: </strong>The mean value of dark focus was 0.53 D ± 0.26 for the entire group. The mean value for early onset myopes was 0.56 D ± 0.29 and for late onset myopes the mean value was 0.47 D ± 0.21. This showed no significant difference (p-value = 0.18). No significant correlation between amount of refractive error and dark focus was found.</p><p><strong>Conclusion: </strong>The Swedish myopes in this study have a smaller mean value of dark focus than mean values found in other studies using the same technique and the previous findings that early and late onset myopes differ in mean values of dark focus is not applied to this study.</p>

There is very strong evidence that ordinary matter in the Universe is outweighed by almost ten times as much so-called dark matter. Dark matter does neither emit nor absorb light and we do not know what it is. One of the theoretically favoured candidates is a so-called neutralino from the supersymmetric extension of the Standard Model of particle physics. A theoretical calculation of the expected cosmic neutralino density must include the so-called coannihilations. Coannihilations are particle processes in the early Universe with any two supersymmetric particles in the initial state and any two Standard Model particles in the final state. In this thesis we discuss the importance of these processes for the calculation of the relic density. We will go through some details in the calculation of coannihilations with one or two so-called sfermions in the initial state. This includes a discussion of Feynman diagrams with clashing arrows, a calculation of colour factors and a discussion of ghosts in non-Abelian field theory. Supersymmetric models contain a large number of free parameters on which the masses and couplings depend. The requirement, that the predicted density of cosmic neutralinos must agree with the density observed for the unknown dark matter, will constrain the parameters. Other constraints come from experiments which are not related to cosmology. For instance, the supersymmetric loop contribution to the rare b -&gt; sγ decay should agree with the measured branching fraction. The principles of the calculation of the rare decay are discussed in this thesis. Also on-going and planned searches for cosmic neutralinos can constrain the parameters. In one of the accompanying papers in the thesis we compare the detection prospects for several current and future searches for neutralino dark matter.

Syftet med denna uppsats är att undersöka på vilket sätt musik och filmrum interagerar med varandra i filmmusikalerna ”Dancer in the Dark” och ”Chicago”. Detta görs huvudsakligen med utgångspunkt från Richard Dyers teorier kring rumsgestaltning inom filmmusikaler, men också utifrån deras roll som förmedlare av utopiska värden, samt Michel Chions teorier kring ljudets olika effekter på film. Vilka värderingar och budskap filmerna har och hur de kommer fram diskuteras också. Resultatet av analyserna visar att de två filmernas sätt att arbeta med rum och musik skiljer sig markant, men att de båda för fram ett samhällskritiskt budskap.

Dark Tourism is a relatively new concept, but as a phenomenon it has existed for centuries in the form of pilgrimages and gladiator games. The term includes visits to places associated with death and disaster, and has in more recent years become a highlighted tourist niche. This paper addresses the phenomenon of Dark Tourism and the reasons behind a visit to such an attraction. To find out the motive behind people's visits, interviews were conducted with respondents who have previously visited one or more Dark Tourism sites. A total of 32 people were interviewed about what influenced them to go to such a macabre place. Observations were also performed on five Dark Tourism attractions, in order to provide a greater understanding for their attractiveness and appeal.In our research we found that, often, a multiple reasons lay behind the choice to visit a Dark Tourism site. Two of the main reasons stated by the respondents for their visits, were history and education, with the motivation that the abovementioned referees wanted to experience and learn about the past simultaneously. We also found that curiosity for attractions characterized as “different”, was a strong motivation for many of our interviewed. / Dark Tourism är ett relativt nytt begrepp men fenomenet har existerat i århundraden exempelvis i form av pilgrimsfärder och gladiatorspel. Begreppet innefattar besök till platser som kopplas till död och katastrofer, vilket har blivit en turistnich som uppmärksammats mer under de senaste åren. Denna uppsats tar upp fenomenet Dark Tourism och vilka motiven är till att besöka en sådan attraktion. För att få reda på motivet bakom människors vistelser har intervjuer utförts med respondenter som besökt Dark Tourism områden. Sammanlagt intervjuades 32 personer kring vad som påverkat dem att åka till en sådan makaber plats. Observationer har även utförts på fem Dark Tourism attraktioner för att ge en större förståelse kring deras dragningskrafter.    I arbetet fann vi att det ofta fanns flera motiv till ett besök på en Dark Tourism plats. Historia och utbildning var ett av de främsta skälen till besöken då de ville uppleva och få kunskap om det förgångna. Vidare framkom det att nyfikenhet av att besöka en annorlunda attraktion för många utgjorde ett starkt motiv till deras besök.

The abundance of satellite galaxies is a critical small-scale test of the standard cosmological model. From comparing the predictions of structure formation in simulations with observations of Local Group dwarf galaxies there is a clear mismatch in the abundance, leading to the so-called “missing satellites” problem. The comparison between simulation and observation have, however, suffered from a limited sample of satellite galaxies, with the only reasonably complete sample being from the most local galaxy groups. It is unknown whether the observed abundance of dwarf satellite galaxies of the nearest groups is statistically representative of the abundance of dwarf satellites in the greater universe. We construct a volume-limited sample of galaxies down to a well-defined stellar mass limit (M★ ≥ 6 × 109 Msun ) using the Atlas3D parent sample of spiral and ellipsoidal galaxies by Cappellari et al. 2011. In order to statistically identify bound satellites around galaxies in our primary catalogue, we apply cuts on the background based on the properties of known dwarf satellites of the Local Group using both the Sloan Digital Sky Survey Data Release 8 (SDSS DR8) (http://www.sdss3.org/dr8/) spectroscopic and photometric galaxy catalogues. We detect an over-density of faint objects at projected separations of < 500 kpc at S/N ∼ 8, corresponding to an average of 4.8 ± 0.65 satellite detections per primary after stacking these systems and subtracting the background. We further find that the over-density of faint objects strongly depends on primary morphology and magnitude. While the Milky Way seems to be unusual in its number of bright satellites, our faint end satellite abundances are in agreement from the ∆m luminosity function for primaries in our sample as bright as the Milky Way. Our work has extended the work of previous authors by several magnitudes further down the faint end of the luminosity function.

The dark focus is a resting state of accommodation, which occurs when there are not enough stimuli for the eye to focus on. This means that the eye becomes more myopic and some people notice a blur for example at night time, more known as night myopia. In this study the dark focus in Swedish myopes is measured and any difference between early and late onset myopes is investigated. Method: The dominant eye of 56 myopes was first measured with static retinoscopy, using a distant target, and then with near retinoscopy, with the retinoscope beam as the target. The full working distance of 2.00 D was subtracted in both methods and the values were compared. The difference, if any, was the dark focus. Results: The mean value of dark focus was 0.53 D ± 0.26 for the entire group. The mean value for early onset myopes was 0.56 D ± 0.29 and for late onset myopes the mean value was 0.47 D ± 0.21. This showed no significant difference (p-value = 0.18). No significant correlation between amount of refractive error and dark focus was found. Conclusion: The Swedish myopes in this study have a smaller mean value of dark focus than mean values found in other studies using the same technique and the previous findings that early and late onset myopes differ in mean values of dark focus is not applied to this study.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 201-212).

Not available / text

A detector with a target mass of 7 kg of liquid argon was designed, constructed and operated at Queen’s University. This detector is a scaled model for the DEAP project toward a tonne-scale argon detector to search for the WIMP candidate of the so far undetected, dark matter of the universe. The primary intent of the scaled detector was to measure the achievable level to reject background events by use of pulse shape discrimination, being based upon the scintillation timing properties of liquid argon. After refining the apparatus and components, the detector was in operation from the 20th of August until the 16th of October 2007 before being moved to its current location in SNOLAB. During this time, a population of 31 million well-tagged gamma events were collected, of which 15.8 million were in the energy range of interest for calibration. This population was sufficient to demonstrate the discrimination of background events by pulse shape discrimination at the level of 6.3 × 10-8. An analytical model was constructed, based on the scintillation processes and detector response, and has been sufficiently investigated to make predictions of further achievable discrimination. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2008-04-25 01:39:39.121

One of the pressing concerns in Dark Matter detection experiments is ensuring that the potential signal from exceedingly rare Dark Matter interactions is not obscured by background from interactions with more common particles. This work focuses on the ways in which alpha particles from primordial isotopes in the DEAP detector components can cause background events in the region of interest for Dark Matter search, based on both Monte Carlo simulations and data from the DEAP-1 prototype detector. The DEAP experiment uses liquid argon as a target for Dark Matter interactions and relies on the organic electroluminescent dye tetraphenyl butadiene (TPB) to shift the UV argon scintillation light to the visible range. The light yield and pulse shape of alpha particle induced scintillation of TPB, which is an essential input parameter for the simulations, was experimentally determined. An initial mismatch between simulated and measured background spectra could be explained by a model of geometric background events, which was experimentally confirmed and informed the design of certain parts of the DEAP-3600 detector that is under construction at the moment. Modification of the DEAP-1 detector geometry based on this model led to improved background rates. The remaining background was well described by the simulated spectra, and competitive limits on the contamination of acrylic with primordial isotopes were obtained. Purity requirements for the DEAP-3600 detector components were based on this work. The design and testing of a novel large area TPB deposition source, which will be used to make TPB coatings for the DEAP-3600 detector, is described. / Thesis (Ph.D, Physics, Engineering Physics and Astronomy) -- Queen's University, 2012-08-09 13:12:52.26