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Determining the cosmic star formation history of the Universe is fundamental for our understanding of galaxy formation and evolution. While surveys now suggest that the "epoch" of galaxy formation occurred more than 6 billion years ago, our measurements still suff er from signi ficant scatter and uncertainties due to the use of diff erent indicators, dust extinction and the e ffects of cosmic variance in the current samples. Furthermore, understanding galaxy formation and evolution require us to go much beyond simply determining the star formation history of the Universe with high accuracy: what are the physical mechanisms driving the strong evolution that we observe? How does star formation depend on stellar mass and environment and how does that change with cosmic time? This thesis presents both a completely self-consistent determination of the star formation history of the Universe (based on a single, sensitive and well-calibrated star formation indicator up to redshift z ~ 2:3: the H α luminosity) and investigates its drivers by exploring large area surveys (probing a range of environments and overcoming cosmic variance) obtained with the High-redshift Emission Line Survey (HiZELS). HiZELS is a panoramic extragalactic survey using the WFCAM instrument on the 3.8-m UK Infrared Telescope (UKIRT) which utilizes a set of existing and custom-made narrow-band filters in the J, H and K bands to detect emission line galaxies (main targets are H α emitters at z = 0:84, z = 1:47 and z = 2:23) up to z ~ 9 over square degree areas of extragalactic sky. Detailed measurements of the H α luminosity function and its evolution with redshift are presented, revealing a signi ficant luminosity evolution. The clustering properties of H α emitters at high-redshift are quantifi ed and investigated for the first time, revealing that these distant galaxies reside in Milky-Way type dark matter haloes at z ~ 1. Mass and environment are found to have important and inter-dependent roles on star formation at high-z and the results are able to reconcile previously contradictory results in the literature. Furthermore, by conducting a novel double-narrow band survey at z = 1:47, the relationship between the [Oii]3727 and H α emission lines is studied in detail and directly compared to z ~ 0, showing no signifi cant evolution in the dust properties of star-forming galaxies, despite the very strong luminosity evolution. Finally, this thesis also presents the widest search for very distant Ly α emitters at z ~ 9.

A unique K-band selected high-redshift spectroscopic dataset (UDSz) is exploited to gain further understanding of galaxy evolution at z > 1. Acquired as part of an ESO Large Programme, this thesis presents the reduction and analysis of a sample of ∼ 450 deep optical spectra of a random 1 in 6 sample of the KAB < 23, z > 1 galaxy population. Based on the final reduced dataset, spectrophotometric modelling of the optical spectra and multi-wavelength photometry available for each galaxy is performed using a combination of single and dual component stellar population models. The stellarmass and age estimates provided by the spectrophotometric modelling are exploited throughout the rest of the thesis to investigate the evolution of massive galaxies at z > 1. Focusing on a K-band bright (K < 21.5) sub-sample in the redshift range 1.3 < z < 1.5 the galaxy size-mass relation has been studied in detailed. In agreement with some previous studies it is found that massive, old, early-type galaxies (ETGs) have characteristic radii a factor ~- 1.5 − 3.0 smaller than their local counterparts at a given stellar-mass. Due to the potential errors in spectrophotometric estimates of the stellarmasses at high redshift velocity dispersion measurements are derived for a sub-sample of massive ETGs at z > 1.3 in order to calculate dynamical mass estimates. To date, only a handful of objects at z > 1.3 have individual velocity dispersion estimates in the literature. Here the largest single sample (13 objects) of velocity dispersion measurements at high redshift is presented. The results for the sub-sample of objects with dynamical mass estimates confirm the results based on stellar mass estimates that high redshift massive systems are more compact than their local counterparts. The fraction of K-band bright objects at high redshift that are passively evolving is calculated with specific star-formation rates from the UV rest-frame continuum, [OII] emission and 24μm data. It is concluded that ∼ 58 ± 10% of the K < 21.5, 1.3 < z < 1.5 galaxy population is passively evolving. Various photometric techniques for separating star-forming and passively evolving galaxies are assessed by exploiting the accurate spectral types derived for the UDSz spectroscopic sample. Popular highredshift selection techniques are shown to fail to effectively select complete samples of passive objects with low levels of contamination. Using detailed information available for the UDSz dataset, various techniques are optimised and then used to estimate the passive fraction from the full UDS photometric catalog. The passive fraction results from the full photometric catalog are found to agree well with the results derived from the UDSz sample. With the Visible and Infrared Survey Telescope for Astronomy (VISTA) now starting to produce data, the opportunity has been taken to develop high-redshift galaxy population dividers based on the VISTA filters. Using the first data release from the VISTA Deep Extragalactic Observations (VIDEO) survey (VVDS D1 field), the passive fractions of K-band limited samples have been estimated to compare with results derived in the UDS. Within the errors the passive fraction estimates in the UDS and VISTA VVDS D1 field are found to agree reasonably well. Finally, composite spectra are used to study the evolution of various different galaxy sub-samples as a function of redshift, age, stellar-mass and specific star-formation rate. This work produces an remarkably clean result, showing that the massive, absolute Kband bright, passively evolving ETGs are always the oldest population, with ages close to the age of the Universe at z ∼ 1.4. In contrast, the late-type, low-mass, star-forming galaxies are always found to be much younger systems. This result strongly supports the downsizing scenario, in which more massive systems complete their stellar-mass assembly before lower-mass counterparts.

This investigation undertakes to re-centre the figure of the film star and their film appearances in the field of star study. To this end it uses Charlton Heston as its focus in a re-appraisal of existing methods of accounting for the star phenomenon in cinema. It also concomitantly re-assesses existing accounts of the significance of Charlton Heston as a film star. This thesis posits a robust method for identifying the specificities of the star’s contribution to a film’s meanings and effects across the body of their work by drawing on Andrew Britton’s understanding of the ‘star enactment’. Present approaches through which to engage with the details of a star’s performance are considered in detail and the weaknesses of those that seek to impose external schemas onto such discussions are highlighted. The difficulties with approaches that attempt to account for the star as a signifying phenomenon through the concepts of acting and performance are also considered. Existing methods which may allow for a fruitful investigation into the significance of the star enactment, such as the commutation test, are re- formulated in this study and their benefits are demonstrated through their application to key Heston star enactments. These new understandings are also made possible through the application of an ‘ekphrastic’ method of rendering film moments. Previous readings of Heston’s star figure are also re- appraised, and their conclusions questioned, through closer reference to the evidence of details from films. The fruitfulness of this method for analysing and commenting on film is thus demonstrated and Heston’s relationship to genre and its effect on performance style is also considered in order to be able to confidently assert the specific features of the Heston aesthetic.

No description available.

Bakgrund: Knäskador är vanligt förekommande bland yngre fysiskt aktiva personer. Ofta skadas flera strukturer samtidigt vilket medför att den mekaniska stabiliteten i knäleden försämras samt att den neuromuskulära funktionen i benet försämras, vilket påverkar den posturala kontrollen samt stabiliteten på knät. För att upptäcka instabilitet behövs mer utmanande och specifika test som Star Excursion Balance Test (SEBT). I dagsläget saknas studier gjorda med SEBT på en svensk population. Fysioterapeuter är beroende av tillförlitliga instrument för att kunna göra en korrekt bedömning. Syfte: Syftet med studien var att undersöka test-retest reliabiliteten för SEBT samt att undersöka samtidig validitet mellan SEBT och Unilateral Stance test (UST) för personer med knäproblematik.Syftet var dessutom att undersöka hur den posturala kontrollen var för personer i åldrarna 20-30 år med knäproblematik mätt med SEBT och UST. Metod: Studien var gjord med en icke experimentell design som var både deskriptiv och korrelerande. Alla tester gjordes vid ett tillfälle med 5 minuters vila mellan testerna. I studien ingick 30 personer med diagnostiserad alternativt självupplevd knäproblematik i åldern 20-30 år som studerade på Biomedicinskt centrum vid Uppsala Universitet. Resultat: Den posturala kontrollen för testpersonerna (n=30) var uppmätt till god både mätt med både SEBT och UST. Validiteten mellan SEBT och UST var låg r=0,3 (p=0,12). Test-retest reliabiliteten för SEBT var god r=0,74 (p=0.00013). Konklusion: SEBT har en god interbedömarreliabilitet. Korrelationen mellan UST och SEBT var låg. SEBT är ett test som är ett väldigt specifikt test där man behöver både material och tid för utförandet. Det behövs mer studier för att få fram om testet går att användas effektivt på allmänna kliniker som ett utvärderingsinstrument för postural kontroll. Keywords: Postural balance, Dynamic balance, Reliability, Validity, Star excursion balance test (SEBT), Unilateral stance test (UST), knee injury.

The newest European high performance material testing reactor, the Jules Horowitz Reactor, is under construction at CEA Cadarache research center in France. The reactor will support existing and future nuclear reactor technologies, with the first criticality expected at the end of this decade. The current/reference CEA methodology for simulating the thermalhydraulic behavior of the reactor gives reliable results. The CATHARE2 code simulates the full reactor circuit with a simplified approach for the core. The results of this model are used as boundary conditions in a three-dimensional FLICA4 core simulation. However this procedure needs further improvement and simplification to shorten the computational requirements and give more accurate core level data. The reactor’s high performance (e.g. high neutron fluxes, high power densities) and its design (e.g. narrow flow channels in the core) render the reactor modeling challenging compared to more conventional designs. It is possible via thermal-hydraulic or solely hydraulic Computational Fluid Dynamics (CFD) simulations to achieve a better insight of the flow and thermal aspects of the reactor’s performance. This approach is utilized to assess the initial modeling assumptions and to detect if more accurate modeling is necessary. There were no CFD thermal-hydraulic publications available on the JHR prior to the current PhD thesis project. The improvement process is split into five steps. In the first step, the state-of-the-art CEA methodology for thermal-hydraulic modeling of the reactor using the system code CATHARE2 and the core analysis code FLICA4 is described. In the second and third steps, a CFD thermal-hydraulic simulations of the reactor’s hot fuel element are undertaken with the code STAR-CCM+. Moreover, a conjugate heat transfer analysis is performed for the hot channel. The knowledge of the flow and temperature fields between different channels is important for performing safety analyses and for accurate modeling. In the fourth step, the flow field of the full reactor vessel is investigated by conducting CFD hydraulic simulations in order to identify the mass flow split between the 36 fuel elements and to describe the flow field in the upper and lower plenums. As a side study a thermal-hydraulic calculation, similar to those performed in previous steps is undertaken utilizing the outcome of the hydraulic calculation as an input. The final step culminates by producing an improved, more realistic, purely CATHARE2 based, JHR model, incorporating all the new knowledge acquired from the previous steps. The primary outcome of this four year PhD research project is the improved, more realistic, CATHARE2 model of the JHR with two approaches for the hot fuel element. Furthermore, the project has led to improved thermal-hydraulic knowledge of the complex reactor (including the hot fuel element), with the most prominent findings presented. / <p>QC 20161208</p> / DEMO-JHR

Les naines brunes sont des astres incapables de déclencher et soutenir des réactions nucléaires dans leur cœur. En l’absence de cette source d’énergie, leur luminosité diminue avec le temps jusqu’à leur extinction complète. Leur flux aux longueurs d’onde de 0,8 à 2,35 μm est particulièrement altéré par l’humidité contenue dans l’atmosphère terrestre, ce qui complique l’étude de ces astres. Le but de la présente recherche est de vérifier si la division par un spectre d’étoile A0 est un moyen de corriger l’altération causée par l’atmosphère terrestre sur cette partie de leur spectre. Tout d’abord, des notions, pertinentes à la compréhension de ce travail, sont abordées. L’introduction présente quelques notions sur les naines brunes et sur l’atmosphère terrestre. Le deuxième chapitre concerne le traitement des données. Il traite de la calibration, de la mise en évidence du problème de non-répétabilité de la position de la fente du spectromètre SIMON ainsi que de ses causes. Il porte aussi sur l’uniformisation de la réponse des pixels et de la soustraction du ciel pour extraire les spectres. La méthode employée pour étudier l’effet de l’atmosphère terrestre sur les spectres de naines brunes y est présentée. Le troisième chapitre analyse les résultats obtenus par l’utilisation de l’étoile de référence de type A0 comme calibration pour corriger le spectre de naine brune, en assumant un même effet de l’atmosphère terrestre sur les deux types d’astres. Nous ne pouvons conclure, avec certitude, que l’absorption tellurique affecte de la même façon les deux spectres ni de quelle façon exactement ils sont affectés. Une recherche supplémentaire nécessitant de nouvelles prises de données à des masses d’air et à des taux d’humidité variés est requise. / Brown dwarfs are celestial bodies unable to sustain nuclear reactions. For this reason their luminosity declines until complete extinction. Their flux, particularly in the band between 0,8 and 2,35 μm, is absorbed by the water vapor in the terrestrial atmosphere. The goal of this research is to find a way to correct this part of their spectra affected by this effect. First, general notions needed to understand the project are exposed. The second chapter concerns the data reduction. The calibration, the problem of the position repeatability of the slit of the spectrometer SIMON and his cause are exposed. It discusses techniques to even up the pixels’ response and the substraction of the sky from the spectra. The method used to study the atmosphere effect on brown dwarf spectra is presented. The third chapter analyses the results that use the A0 reference star to correct the brown dwarf spectrum. We cannot conclude that the A0 spectrum is affected in the same way as the brown dwarf spectrum by the terrestrial atmosphere. The data from a single night do not allow a good analysis of this effect as a function of air mass and humidity level. Others missions are needed.

Modern automotive applications such as transmission clutch plates, combustion chambers, diesel fuel injector tips, and axle gears and friction plates operate at temperatures that can exceed 250°C and pressures of 40,000 psia. Industrial practice is to add homopolymers and copolymers to base oils to modify bulk fluid viscosity and frictional properties for these demanding applications. However, designing polymeric additives for lubricants and predicting their performance is limited by the lack of available high-temperature high-pressure (HTHP) viscosity and density data needed to test contemporary lubricity models. Thus, a major objective of this thesis is the design, development, and commissioning of a rolling ball viscometer/densitometer (RBVD) capable of simultaneously determining fluid densities and viscosities at temperatures in excess of 250°C and pressures of 40,000 psia. Resulting data may then be generated to directly address the fundamental need for lubricant property data at these HTHP conditions. The design and development of the RBVD is described in detail to highlight the design iterations and modifications utilized to ensure robust operation at extreme conditions. Three significant and novel features of this RBVD apparatus that distinguish and differentiate it from other apparatus of this type are: (1) specially designed metal-to-metal and sapphire-to-metal seated surfaces capable of eliminating temperature- and chemically-sensitive elastomeric seals; (2) use of a bellows piston to eliminate significant temperature and operational constraints; and (3) incorporation of a linear variable differential transducer (LVDT) to simultaneously permit determination of solution density and viscosity. A detailed analysis of initial accumulated uncertainty for the experimental viscosity and density techniques revealed the need for key RBVD modifications. Final data are presented showing that the RBVD is capable of measuring viscosities with an accuracy of ± 2 to 3 percent and densities to ± 0.7 percent, including at the extreme operating conditions targeted. A second objective of this thesis is the measurement of HTHP viscosities of star polymer-solvent mixtures to determine the impact of star polymer architecture on solution viscosity at extreme conditions similar to those that might be experienced in automotive applications. This objective is motivated by current challenges facing industry to identify polymeric additives that can be added to base oils to improve fuel economy and allow for the implementation of novel hardware technology that relies on enhanced lubricant properties. Relative to linear polymers, the unique architecture of star polymers enhances polymer solubility in base oils while having a more favorable impact on viscosity and density properties over a wide range of temperatures and pressures. Data are presented for an industrially-relevant star polymer in octane to assess the impact of the star configuration on solvent viscosity at extreme conditions. The star polymer used in this instance consists of an ethylene glycol dimethacrylate (EGDMA) core with poly(lauryl methacrylate-co-methyl methacrylate) (LMA-MMA) arms. The star polymer has a total weight averaged molecular weight (Mw) and Mw of each arm of 575,000, and 45,000, respectively. The copolymer arms of the star polymer have an LMA-to-MMA mole ratio of 0.6. The results of further viscosity studies are presented for a model system of well-characterized commercially available narrow polydispersity index (PDI) star polystyrenes (PS) in toluene. Each PS is evaluated at a two percent by weight concentration in toluene to evaluate the effect of arm molecular weigh on viscosity. Each three-arm star polymer has arm and total molecular weights ([arm Mw] total star Mw) of ([15,400] 41,200), ([36,000] 97,600), and ([108,000] 305,000). In this instance, the viscosity of toluene increased by more than a factor of three for the star with the highest Mw arms.

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.