Cholesterol and fatty acyl-coenzymeA thioesters are signalling molecules with role in regulation of genes involved in lipid and glucose transport and metabolism. The studies described herein focused on three proteins that bind lipids and have different cellular functions: steroidogenic acute regulatory protein (StAR), hepatocyte nuclear factor-4a (HNF-4a) and acyl-CoA binding protein (ACBP). First, StAR mediates delivery of cholesterol to inner mitochondrial membrane in steroidogenesis by a poorly understood mechanism. In our studies, fluorescent NBD-cholesterol binding assays demonstrate that StAR binds cholesterol at two binding sites with 32 nM Kds and circular dichroism spectra show that cholesterol binding results in changes of StAR secondary structure. Fluorescent sterol exchange assays between donor and acceptor mitochondrial membranes indicate that StAR significantly increased the formation of rapidly transferable cholesterol domains. Second, HNF-4a, a nuclear receptor, had been shown to bind fatty acyl-CoAs as natural ligands with apparent low affinities obtained with radiolabeled ligand binding assays. Our fluorescence spectroscopy studies demonstrate that HNF-4a ligand binding domain (HNF-4aLBD) binds acyl-CoAs at a single binding site with Kds of 1.6-4 nM. Fluorescence resonance energy transfer (FRET) between HNF-4aLBD tryptophan residues and cis-parinaroyl-CoA yielded an intermolecular distance of 42 Â thus pointing to direct molecular interaction. Third, although ACBP has been detected in the nucleus, it is not known whether ACBP may directly and/or functionally interact with a nuclear acyl-CoA binding protein such as HNF-4a to regulate transcription. Our present studies in vitro and in intact cultured cells, including circular dichroism of HNF-4a in the presence of ACBP, coimmunoprecipitation of HNF-4a/ACBP complexes, ACBP and HNF-4a colocalization in nuclei of cells by confocal microscopy demonstrate a physical association of ACBP and HNF-4a. FRET microscopy data indicated an intermolecular distance of 53 Â between ACBP and HNF-4a in rat hepatoma cells. Functional assays (transactivation of an HNF4a-dependent reporter gene) showed significant increase in the presence of ACBP in two different cell lines. Expression of ACBP anti-sense RNA decreased HNF-4a-mediated transactivation, pointing to a role of ACBP in co-regulating HNF-4a-dependent transcription.

We give an explicit construction of the trace on the algebra of quantum observables on a symplectic orbifold and propose an index formula.

Background Strategic alliances have become increasingly popular within the business world, they can be seen as a way to improve the total output of the firm. Over the last 10 years, the industry endured trying times, the most notable being the events of September 11, 2001. That event drastically changed airline traveling all across the world. It also showed the importance of collaborations in order to stay competitive. Star Alliance began in 1997 and has since then grown into the world’s largest airline alliance with a total market share of 25.1%. Purpose The raison d’être of this study is to quantify and analyze the augmentation of load factors over time, in terms of distribution, as they pertain to capacity performance of allied carriers within Star Alliance. Method In order to fulfill the purpose, a deductive approach to the research has been taken. Furthermore, due to the nature of the data, a quantitative approach has been used within. Two hypotheses will be stated and several research questions as well. Result It can be clearly seen that distribution of load factors has transformed during the years. There is a shift in both the skewness and the kurtosis of the distributions that can be seen when examining the frequency distribution charts. The kurtosis increases and the skew decreases, measures that are positive for the airlines, while the anomalies of 0% and 100% load factor have remained stable throughout the years. A general increase in the average load factors has also been seen. Conclusion By analyzing the empirical findings, it is clear that the load factor of the allied members has increased and that the proportion of the denied boardings decreased in relation to the average load factor. This means that the alternative hypothesis was accepted in the first hypothesis and that the second alternative hypothesis was accepted in the second hypothesis. The research also reveals a generally increased mean which together with the changes in the skew and kurtosis lead to an acceptance of the beta distribution. Furthermore, higher load factors were shown to have a strong correlation with the increase in efficiency and decrease in overselling.

The central line-depths of absorption lines depend upon stellar temperature. By dividing the central line-depth of such a line with a central line-depth independent of temperature, a thermometer of relative star temperatures is obtained in the form of a line-depth ratio (LDR), once it is related to an effective temperature scale. Such thermometers are known to give precise results which is why the method is pursued. The purpose of this work is to rank LDRs according to a set of criteria to find the most suitable ratio to measure temperature. This is done based on a set of LDRs measured for a large sample of dwarf stars with known effective temperature, atmospheric pressure and chemical composition. Numerous LDRs are eliminated because their temperature dependence are limited to a short temperature interval. Further LDRs are eliminated due to dependence on the atmospheric pressure and chemical composition of the LDR. The remaining LDRs are ranked based on the strength of temperature dependence, the fit of the representative polynomial to the data points and the number of data points available. The best ranked LDR provides a temperature resolution smaller than 10 K over a temperature interval of 4500-6250 K, assuming an uncertainty in LDR of 0.01.

This study looks at how media representations change regarding Somalis in Minneapolis, Minnesota, USA, under the course of a project called “I AM A STAR for Somalia”, launched in April 2011. A quantitative content analysis of print media is employed, concentrating on factors such as actors, subjects, patterns of quoting, involvement and article prominence. Various studies are used as a foundation, including Teun Van Dijk (1991), which introduce and explain theories such as Ideology and Racism, Agenda Setting, Minimal Effects and Integration. Ultimately, the analysis reveals a change in media portrayals correlating with the I AM A STAR project; Somalis are portrayed in roles and stories which normalise their representation in the year following the launch. In the second year, however, these positive effects are not as apparent.

Purpose/aim The aim is to examine the distribution of hotel ownerships and star-rated levels in different regions. This thesis depends on the analysis of the examination to find out if the change of investment behaviors can decrease or avoid the adverse effects of bureaucracy in the Chinese hotel industry. Design/methodology/approach Data has been collected through the third-party electronic distribution channel. The analysis includes a description of the samples and statistical tests. Findings The analysis showed that there is a connection between hotel ownerships, star-rated levels, and different regions. The adverse effects of bureaucracy in the second-tier cities and third-tier cities are stronger than that in the first-tier cities and tourist cities. The state-owned hotels also can do the enterprise transformation in the tourist cities to avoid or decrease the adverse effects of the bureaucracy. Originality/value The original idea is using the hotel ownerships distribution in different regions to find out the different levels of adverse effects of the bureaucracy in different regions. This thesis should be a meaningful contribution to knowledge development.

(Abridged) Physical processes regulating star formation in satellite galaxies represent an area of ongoing research, but the projected nature of observed coordinates makes separating different populations of satellites (with different processes at work) difficult. The present-day phase space coordinates of a satellite galaxy carry information about its orbital history, which can then be compared to its star formation history (SFH). This is expected to reveal both a trigger time and timescale for environmental quenching. Finally, this can be related back to the physical process(es) regulating star formation in high density environments. We use merger trees from the MultiDark Run 1 N-body simulation to compile a catalogue of satellite orbits in cluster environments. We parameterize the orbital history by the time since crossing within 2.5 virial radii of the cluster centre and use our catalogue to estimate the probability density over a range of this parameter given a set of projected phase space coordinates. We show that different populations of satellite haloes occupy (semi-)distinct regions of (projected) phase space. We generalize this result by producing a probability distribution function (PDF) of possible infall times at every point in projected phase space. We apply our method to determining the infall time PDFs of a large sample of observed cluster satellite candidates from the Sloan Digital Sky Survey. We use galaxy colour as a proxy for SFH and model the distribution of satellite galaxy colours as two gaussian populations. We derive a Markov chain Monte-Carlo method to obtain the colour distribution as a function of the time since infall into the cluster environment. Our implementation of this method is still being tuned, but we use a second simpler (but much cruder) method to obtain an estimate of the evolution of the colour distribution. Our results are suggestive of a quenching process that begins within perhaps ±1 Gyr of virial radius crossing and which slows after pericentric passage. We stress that results obtained with this second method come with important caveats.

It has become clear that the global star formation rate in the Universe has been decreasing since at least z~1, and blue, star-forming galaxies are transformed into red, passive galaxies through one or more processes. The origin of this decline and transformation remains unclear. The role environment plays in all this is especially uncertain. Despite the observed domination of a passive population in the cores of clusters, in contrast to the more actively star-forming field population, whether or not, and how environment affects the properties of galaxies when they fall into clusters is an unsettled question. In this thesis, we look into these issues by examining both the passive and star-forming galaxies, from the cores out to the infall regions, in a large sample of clusters at 0.15<z<0.36 we detected from the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). We find that in the cores of clusters, the red-sequence galaxies are a mixture of two populations, indicated by the inflexion in their luminosity function. There is no strong evolution in the shape of the red-sequence between z~0.4 and z~0.2; however, from z~0.2 to today, there is a rapid increase in the number of faint galaxies on the red-sequence relative to the bright ones, suggesting a rapid quenching of the faint galaxies in cluster cores within the last few billion years. At z~0.2, we find that the red fraction (star-forming fraction), at all stellar mass explored (9.0<log10(M*/M_solar)<11.5), shows no dependence on the distance from cluster centres, in the range 3<r<7Mpc; but within the inner 3 Mpc, we see a clear increase (decrease) in the red fraction (star-forming fraction). Also, for the lowest stellar mass galaxies, their red fraction has increased by a factor of 2 from z~0.3 to z~0.2 (over 1 Gyr), and yet we do not detect any difference between the star formation properties of the star-forming galaxies in clusters at all radii and that in the field. This suggests that for the low mass galaxies, it is likely that a mechanism that truncates star formation rapidly (within 1 Gyr) is at work. In the outskirts of the clusters, despite the low density contrast with the field, the red fraction is still higher than that in the field, suggesting that those galaxies have had their star formation quenched relative to the field population, supporting the pre-processing scenario.

Attitude estimation and angular velocity estimation are the most critical components of a spacecraft's guidance, navigation and control. Usually, an array of tightlycoupled sensors (star trackers, gyroscopes, sun sensors, magnetometers) is used to estimate these quantities. The cost (financial, mass, power, time, human resources) for the integration of these separate sub-systems is a major deterrent towards realizing the goal of smaller, cheaper and faster to launch spacecrafts/satellites. In this work, we present a novel stellar imaging system that is capable of estimating attitude and angular velocities at true update rates of greater than 100Hz, thereby eliminating the need for a separate star tracker and gyroscope sub-systems. High image acquisition rates necessitate short integration times and large optical apertures, thereby adding mass and volume to the sensor. The proposed high speed sensor overcomes these difficulties by employing light amplification technologies coupled with fiber optics. To better understand the performance of the sensor, an electro-optical model of the sensor system is developed which is then used to design a high-fidelity night sky image simulator. Novel star position estimation algorithms based on a two-dimensional Gaussian fitting to the star pixel intensity profiles are then presented. These algorithms are non-iterative, perform local background estimation in the vicinity of the star and lead to significant improvements in the star centroid determination. Further, a new attitude determination algorithm is developed that uses the inter-star angles of the identified stars as constraints to recompute the body measured vectors and provide a higher accuracy estimate of the attitude as compared to existing methods. The spectral response of the sensor is then used to develop a star catalog generation method that results in a compact on-board star catalog. Finally, the use of a fiber optic faceplate is proposed as an additional means of stray light mitigation for the system. This dissertation serves to validate the conceptual design of the high update rate star sensor through analysis, hardware design, algorithm development and experimental testing.

Abstract Under the great impact and known to all, the structural changes may be obviously clear that can be observed out, when being not so obvious, should observe whether there are structural changes to appear, it is very difficult to get a clear result clearly to turn into. This paper tries to use such models as Chow test, CUSUM test, CUSUMSQ test, STAR in unknown cases, whether going to assay the data separately has structural changes, various kinds of examination ways of result received are each different to some extent, clear conclusion not unanimous and unified. The dominance the Chow test is the most obvious; Consider heteroscedasticity and autocorrelation restriction in because CUSUM test and CUSUMSQ test model, it is not apt to demonstrate the dominance instead; The STAR depends on state of the materials.