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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.
11

The Sirius System and Its Astrophysical Puzzles: Hubble Space Telescope and Ground-based Astrometry

Bond, Howard E., Schaefer, Gail H., Gilliland, Ronald L., Holberg, Jay B., Mason, Brian D., Lindenblad, Irving W., Seitz-McLeese, Miranda, Arnett, W. David, Demarque, Pierre, Spada, Federico, Young, Patrick A., Barstow, Martin A., Burleigh, Matthew R., Gudehus, Donald 08 May 2017 (has links)
Sirius, the seventh-nearest stellar system, is a visual binary containing the metallic-line A1. V star Sirius. A, the brightest star in the sky, orbited in a 50.13. year period by Sirius B, the brightest and nearest white dwarf (WD). Using images obtained over nearly two decades with the Hubble Space Telescope (HST), along with photographic observations covering almost 20 years and nearly 2300 historical measurements dating back to the 19th century, we determine precise orbital elements for the visual binary. Combined with the parallax and the motion of the A component, these elements yield dynamical masses of 2.063 +/- 0.023 M circle dot and 1.018 +/- 0.011 M circle dot for Sirius. A and B, respectively. Our precise HST astrometry rules out third bodies orbiting either star in the system, down to masses of similar to 15-25 M-Jup. The location of Sirius. B in the Hertzsprung-Russell diagram is in excellent agreement with theoretical cooling tracks for WDs of its dynamical mass, and implies a cooling age of similar to 126 Myr. The position of Sirius. B on the mass-radius plane is also consistent with WD theory, assuming a carbon-oxygen core. Including the pre-WD evolutionary timescale of the assumed progenitor, the total age of Sirius B is about 228 +/- 10 Myr. We calculated evolutionary tracks for stars with the dynamical mass of Sirius A, using two independent codes. We find it necessary to assume a slightly subsolar metallicity, of about 0.85 Z circle dot, to fit its location on the luminosity-radius plane. The age of Sirius. A based on these models is about 237-247. Myr, with uncertainties of +/- 15 Myr, consistent with that of the WD companion. We discuss astrophysical puzzles presented by the Sirius system, including the probability that the two stars must have interacted in the past, even though there is no direct evidence for this and the orbital eccentricity remains high.
12

Vilka behov har IK Sirius fotbollspublik? : En marknadsundersökning på Studenternas Idrottsplats

Granath, Jon January 2008 (has links)
Fotboll kan ses överallt nuförtiden. Det visas nästan ständigt matcher på tv och media rapporterar spaltmeter dagligen. Att likna en fotbollsmatch vid en produkt som ska säljas är i dagens samhälle inte alls någonting konstigt. De olika egenskaper en fotbollsmatch kan ha uppfyller på olika sätt publikens behov. Vilka är dessa behov? Specifikt vad är det som gör att en person väljer att gå och se en fotbollsmatch med Sirius på Studenternas Idrottsplats i Uppsala? Detta är vad denna uppsats avser att undersöka. Som analysverktyg har teorier om kunders behov vid produktinköp använts. Med produkt avses i denna studie Sirius hemmamatcher. För att finna svar på vilka behov som finns hos Sirius publik har en enkätundersökning utförts på Studenternas i samband med matchen mellan Sirius och Degerfors den 4: e augusti. Resultaten som framkom i studien tyder på att det finns en rad olika behov som är viktiga. Själva fotbollens kvalité samt atmosfären och stämningen runt omkring är väldigt betydelsefulla behov för publiken. Vidare är arenafaciliteterna viktiga. Fotbollen ska även uppfylla behovet av underhållning och fungera som en social mötesplats. Att känna passion samt delaktighet i Sirius med- och motgångar är ytterligare starka behov. Sammanfattningsvis kan det sägas att fotboll inte bara är fotboll, utan det kan ses som ett socialt nöje inom vilket en mängd känslor uttrycks. Uppsatsresultaten kan med fördel användas som riktlinjer då marknadsföring och utformning av matchevenemang ska genomföras inom Sirius fotboll.
13

Vägen till framgång : En studie av Uppsalaidrottens sponsormarknad

Andersson, Jonas, Löfgren, Viktor January 2013 (has links)
En idrottsförenings ekonomi är idag avgörande för hur den sportsliga verksamheten kan bedrivas. Många föreningar måste jobba hårt för att få verksamheten att gå runt. Ett sätt att arbeta på för att få in pengar är att locka företag att sponsra verksamheten. Denna studie ställer upp en hypotes för Uppsalaidrotten om ett linjärt samband mellan föreningarnas synlighet hos publik och i media gentemot deras sponsringsintäkter. Studien undersöker sedan om denna hypotes stämmer genom att studera tre idrottsföreningar valda utefter deras synlighet i media och hos publik samt tre företag som sponsrar Uppsalaidrotten. Den insamlade informationen har analyserats med hjälp av en analysmodell baserat på teorier om sponsring. Detta har gett studien en möjlighet att identifiera sponsringens typ och anledningar till sponsringen samt idrottsföreningars arbetssätt. Studien visar att hypotesen stämmer till viss del; föreningarnas synlighet hos publik och i media är den viktigaste faktorn men inte den enda som påverkar. Idrottsföreningarnas företagsnätverk är också en betydande faktor vilket blir tydligt om man ser till föreningarnas satsningar på företagsnätverken.
14

Effects of Aqueous Extracts of Bidens pilosa L. Leaves Against Thioacetamide-Induced Liver Fibrosis in Mice

Wang, Chu-en 02 December 2010 (has links)
Bidens pilosa L. is a traditional Chinese herbal medicine of which was considered as a potential COX2 inhibitor and anti-inflammatory agent. The objective of this study is to discriminate the protective effect of aqueous extract of Bidens pilosa L. leaves (BPLAE) against TAA-induced live fibrosis using an animal model. The herb extracts were administrated via intraperitoneal injection once per week (1.25, 2.5 g/kg), and thioacetamide (200 mg/kg) was injected three times per week and the mice were sacrificed at week 4 and week 8, respectively. Immunohistochemistry staining, Hematoxylin-eosin (HE) staining, Sirius red staining were carried out to evaluate the pathological alterations of mouse livers; in addition, Western blotting was performed to measure the differential expression of £\-smooth muscle actin (£\-SMA) between different treatment groups (vehicle, week 4 and week 8). Hepatic hydroxyproline was also detected in order to compare difference in collagen formation of each group. The results showed that Bidens pilosa L. effectively reduced amount of hepatic hydroxyproline and £\-SMA protein in mice with fibrotic liver induced by TAA. Moreover, in histiopathological exam, the BPLAE treated mice demonstrated a lower collagen and £\-SMA expression, which indicated that BPLAE might reduce degree and severity of liver fibrosis in mice. In conclusion, these results suggested that BPLAE potentially against fibrogenesis in TAA- induced mice liver fibrosis. Additionally, we found that BPLAE might involve in the signaling pathway of MAPK (ERK1/ERK2), which reduced the phosporylation level of p44 but not p42. Further studies using cell base assay to confirm the inhibiting role of BPLAE against cell proliferation or migration is warrant.
15

Jämförelse mellan Scheimpflug imaging och anterior segment OCT i mätning av Corneal tjocklek.

Fournstedt, Daniel January 2015 (has links)
Purpose: The purpose of this study was to compare corneal thickness measured both centrally and midperipherally, between two instruments using different measuring principles. The study also looked at correlation between corneal thickness and intraocular pressure (IOP). Methods: Central and midperipheral corneal thickness was measured on the right eyes of 31 subjects with two different instruments. Instruments were Scheimpflug-camera from Bon Sirius and an AS/OCT from Optos. Measurements were taken on central cornea (CCT) and midperipheral (nasal (NCT), temporal (TCT), superior (SCT) and inferior (ICT)) at a distance of 1.75 mm from the apex. Mean age of the subjects was 23.6 ± 4.5 years. (19-44 years). A CT-80A non-contact tonometer (NonCT) from Topcon was used to measure the intraocular pressure (IOP). Results: A mean-value for central corneal thickness was calculated to 542.4 µm and 540.4 µm for Bon Sirius and AS/OCT repectively. Remaining measured points had mean-values for corneal thickness of, NCT: 577.7 µm & 558.5 µm. TCT: 555.0 µm & 545.2 µm. SCT: 585.7 µm & 554.5 µm. ICT: 563.0 µm & 548.9 µm, respectively. Mean-difference for CCT was 2.4 µm and it showed a significant difference between the two instruments with a p-value of 0.007. Remaining measured points all showed a significant difference of p<0.05. NCT: 19.2 µm. TCT: 9.8 µm. SCT: 31 µm. ICT: 14 µm. A correlation between IOP and CCT measured in both Sirius and AS/OCT was positive with r = 0.7 and p<0.05. Conclusion: The results showed that Sirius gives higher values for corneal thickness then ASOCT in all five measurement points. The results show that these instruments can be used interchangeably when measuring central corneal thickness. However, caution should be used when measuring midperipheral corneal thickness as the there is a significant differences between these two instruments.
16

Nouvelles méthodes d'extraction du Molybdène et géochimie d'un grand gisement fossilifère Cambrien, le Lagerstätte de Sirius Passet

Le Boudec, Ange 26 February 2013 (has links) (PDF)
Les propriétés géochimiques particulières du molybdène vis-à-vis du potentiel d'oxygénation en milieu aqueux en font un élément particulièrement utilisé pour déterminer le degré d'oxygénation du milieu dans lequel un dépôt a sédimenté. Dans un premier temps, ce travail de thèse présente une alternative aux méthodes d'extraction du molybdène utilisées jusqu'ici. Les principales méthodes de purification couramment utilisées sur échantillons géologiques se décomposent en deux phases : une purification au travers d'une résine anionique, puis une purification au travers d'une résine cationique. La méthode proposée ici, initialement prévue pour permettre des analyses en Sample-Standard-Bracketing (SSB), permet d'isoler quantitativement le molybdène du reste de la matrice géologique en un seul passage sur résine anionique. La purification s'avère également suffisamment efficace pour effectuer des analyses en utilisant la méthode du double-spike. Une comparaison de ces deux méthodes de correction du fractionnement instrumental a permis d'évaluer les limites de l'utilisation du SSB par rapport au double-spike. Dans un second temps, cette chimie a été appliquée dans le cadre d'une étude géochimique approfondie d'un gisement fossilifère extrêmement riche: le Lagerstätte de Sirius Passet situé au nord du Groenland. Associée aux critères paléontologiques, cette étude indique que ces sédiments se sont déposés dans un milieu au moins partiellement oxygéné, sous forme de boues sédimentaires très peu propices aux échanges avec la colonne d'eau. Le contexte paléogéographique, les analyses chimiques et les observations microscopiques suggèrent que ces boues sont principalement d'origine éolienne.
17

Påverkas pupilldiametern av ögats refraktiva status?

Gustafsson, Karolina January 2018 (has links)
Purpose: Understanding how pupil size changes under different light conditions is important for refractive surgery, in contact lens fitting, as well as in the development of multifocal contact lenses. It is therefore of great value to have good measurement results and trustworthy methods. The accuracy and repeatability of the instruments used for these measurements are also critical.The purpose of this study was to investigate whether there was a potential relationship between the pupil diameter and the eye's refractive error with the use of the pupilometer incorporated within Sirius. A secondary purpose arose during the study, to evaluate the repeatability of the instrument Sirius. The null hypothesis of this study was; that pupil diameter is greater in myopes than hyperopes and emmetropes - that one would see a decrease in pupil diameter from myopes to emmetropes and also a decrease in pupil diameter from emmetropes to hyperopes. Method: There were 64 participants who took part in this study, aged between 20 to 36 years. Of these, three were excluded because they did not fit the inclusion criteria. The participants were divided into three different groups according to their spherical equivalent refractive errors: there were 26 myopes (range -7.75 D to -0.75 D), 17 emmetropes (range -0.50 D to +0.50 D), and 18 hyperopes (range + 0.75 D to + 5.75 D). Both eyes was measured. Pupil diameter was first measured in Sirius in a darkened room, where the computer was the only light source and the screen's brightness was dimmed. An objective refraction was done with the use of an autorefractor to get an estimated refractive value. Thereafter, retinoscopy was performed in a trial frame with a retinoscopy rack or loose trial lenses. The participants with higher astigmatism were also controlled with the use of the Jackson cross-cylinder. The pupil response was checked in all participants following pupil diameter measurements, to ensure that both eyes did not exhibit pupil defects. The result was analyzed with Excel and GraphPad Prism. Results: Since this study did not find any difference between the right and left eye, the data analysis was performed for right eye only. The mean and standard deviation (SD) of spherical equivalent power for myopes was -2.75 ±1.95 D, emmetropes -0.06 ±0.37 D and hyperopes +1.51 ±1.37 D. This study showed a weak trend between refractive error and pupil diameter, but no significant correlation between pupil diameter and the refractive state of the eye was evident, irrespective of lighting conditions; scotopic (p = 0.38), mesopic (p = 0.17) or photopic (p = 0.16). As expected, a clear decrease in pupil diameter with increased illumination intensity was found. A variance analysis (one-way, repeated measures ANOVA) was performed on the three different measurement in each illumination level, to confirm the repeatability of Sirius. The ICC values were 0.94 for scotopic, 0.87 for mesopic and 0.95 for photopic lighting conditions. Conclusuion: The study shows no significant correlation between pupil diameter and the refractive state of the eye over the range of -7.75 D to + 5.75 D. In this study, we also investigated the repeatability of the measurements values obtained with Sirius using the ICC; this showed that Sirius has a good repeatability in measuring pupil diameter in all three light levels.
18

l'intégrité et la mise à jour dans un système de gestion de bases de données réparties : projet POLYPHEME

Andrade, Juan Manuel 29 October 1980 (has links) (PDF)
On fait le point sur l'ensemble des travaux menés dans le cadre du projet POLYPHEME. On présente l'architecture et les caractéristiques de la maquette réalisée. On étudie les problèmes d'intégrité qui se posent lorsque l'on désire faire coopérer des données dans un environnement reparti, on aborde en particulier l'intégrité sémantique et le traitement des opérations de mise à jour. On propose un formalisme pour exprimer le comportement des mises a jour sur une relation abstraite construite sur d'autres relations.
19

Creating An Editor For The Implementation of WorkFlow+: A Framework for Developing Assurance Cases

Chiang, Thomas January 2021 (has links)
As vehicles become more complex, the work required to ensure that they are safe increases enormously. This in turn results in a much more complicated task of testing systems, subsystems, and components to ensure that they are safe individually as well as when they are integrated. As a result, managing the safety engineering process for vehicle development is of major interest to all automotive manufacturers. The goal of this research is to introduce a tool that provides support for a new framework for modeling safety processes, which can partially address some of these challenges. WorkFlow+ is a framework that was developed to combine both data flow and process flow to increase traceability, enable users to model with the desired granularity safety engineering workflow for their products, and produce assurance cases for regulators and evaluators to be able to validate that the product is safe for the users and the public. With the development of an editor, it will bring WorkFlow+ to life. / Thesis / Master of Applied Science (MASc)
20

Mise en phase des grands interféromètres: Méthode de La Diversité de Phase Chromatique - Développement et Implémentation sur le démonstrateur hypertélescope fibré SIRIUS

Tarmoul, Nassima 10 November 2011 (has links) (PDF)
Afin d'augmenter les capacités d'imagerie et de résolution des instruments d'observation en astronomie, la prospective Haute Résolution Angulaire propose d'augmenter le nombre de sous-pupilles des interféromètres optiques. Associés à des techniques de densification de pupille, les futurs interféromètres seront capables d'imager des cibles astrophysiques faibles et/ou de taille apparente réduite. Il en résulte des contraintes instrumentales constituant le défi technique et technologique dans lequel s'inscrit mon travail de Thèse. Les conditions de propagation et la qualité de recombinaison des faisceaux collectés par chaque sous-pupille régissent les performances en termes de stabilité de l'image et de sensibilité des réseaux optiques. Pour garantir un mélange interférométrique cohérent et la possibilité d'observer sur des temps d'intégrations supérieurs à quelques millisecondes, il est nécessaire de maintenir la différence de marche optique à une valeur inférieure à la fraction de longueur d'onde grâce à un dispositif de cophasage. Je propose une méthode dédiée à la mise en phase des grands interféromètres : la Diversité de Phase Chromatique. Celle-ci est fondée sur une analyse spectrale des images à plusieurs longueurs d'onde permettant de déterminer en temps réel les différences de marche optique à compenser par les lignes à retard de l'instrument. Après une étude théorique et numérique de la méthode à travers l'analyse de cas réalistes, je présente sa mise en œuvre pratique sur le banc hypertélescope fibré SIRIUS développé à l'Observatoire de la Côte d'Azur.

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