My dissertation focuses on a relatively new field of study: the region immediately around galaxies known as the circumgalactic medium (CGM). The CGM holds vast quantities of mass and metals, yet its connection to galaxies is not well understood. My work uses cosmological hydrodynamic simulations and comparisons to data from Hubble's Cosmic Origins Spectrograph (COS) to understand the CGM's connection to galaxy evolution, gas accretion, outflows, star formation, and baryon cycling. This includes studies of the CGM's extent and physical conditions; the cause and nature of outflows; gas dynamics, including the first comprehensive study of tracers of inflowing and outflowing gas at low redshift (z=0.25); and direct comparison of theoretical results to observational data. Chapter 1 introduces my research and show its connection to galaxy evolution. Chapter 2 investigates hydrogen and metal line absorption around low-redshift galaxies in cosmological hydrodynamic simulations. This chapter studies different models for stellar outflows, physical conditions, and dependencies on halo mass. Chapter 3 examines the flow of gas into, out of, and around galaxies using a novel particle tracking technique. This chapter examines the baryon cycle in detail for our preferred model of stellar outflows. Chapter 4 compares our model results, including two separate prescriptions for outflows, with data from COS. We contrast these wind models, showing how they cycle baryons differently, and show degeneracies in observational diagnostics. In Chapter 5, I summarize and discuss plans for future research in this field, and how it can be more fully leveraged to understand galaxy evolution.

I investigate the emission properties of the molecular interstellar medium in protoplanetary disks and galaxy mergers, though focus largely on the latter topic. I utilize both numerical models as well as observations to relate the emission characteristics to physical models for the formation and evolution of gas giant planets and galaxies. The main results of this thesis follow. (1) Gas giant protoplanets may be detectable via self-absorption signatures in molecular emission lines with sufficiently high critical density. Given the spatial resolution of e.g. ALMA, gas giant planets in formation may be directly imageable. (2) Starburst and AGN feedback-driven winds in galaxies can leave imprints on the molecular line emission properties via morphological outflows and high velocity peaks in the emission line spectra. Methods for distinguishing between high velocity peaks driven by dynamics versus those driven by winds are discussed. (3) CO line widths on average trace the virial velocity of z ∼ 6 quasar host halos. Thus, if the earliest quasars formed in ∼1013 M ⊙ halos, they are predicted to have broad molecular line widths. Selection effects may exist which tend quasars selected for optical luminosity toward molecular line widths narrower than the slightline-dependent mean. (4) Using the SMT, I observe a roughly linear relation between infrared luminosity and CO (J=3-2) luminosity in local galaxies confirming the results of recently observed L(IR)-HCN (J=1-0) relations. Subsequent modeling shows that observed SFR-molecular line luminosity relations owe to the average fraction of subthermally excited gas in galaxies, and are simply reflective of the assumed Schmidt law governing the SFR.

I investigate the chemical evolution of the Universe in a series of cosmological hydrodynamic simulations with the purpose of finding a self-consistent evolutionary scenario of galaxy formation able to reproduce key observables focusing on the enrichment of the intergalactic medium (IGM). The most successful models I run and analyze use the scalings of momentum-driven feedback whereby UV photons generated during the Main Sequence stage accelerate dust-driven winds while providing a significantly larger energy budget than from supernovae alone. The success of this outflow model relies on its ability to drive highly mass-loaded winds from small galactic haloes. These feedback relations, supported by observations of local starburst, are inserted into simulations at all epochs, reproducing observables including the C IV column density and linewidth distributions at z=6->1.5 and the O VI forest at z=0-0.5. Outflows at z>=5 propagate early nucleosynthetic products traced by C IV and lower ionization species into an otherwise metal-free IGM. Continual outflows at the peak ages of star formation (z=5->1.5) produce a non-evolving cosmic mass density of C IV despite continual enrichment increasing IGM metallicity by a factor of ten. The z=0-0.5 O VI forest is composed of weaker absorbers tracing photo-ionized diffuse IGM metals, sometimes injected by primordial galaxies, and stronger absorbers tracing recently injected metals, often unable to escape their parent haloes and sometimes collisionally ionized. Tracking the individual histories of metals in outflows shows the average outflow travels ~100 physical kpc and returns to galaxies on an average timescale of 1-2 Gyr; this result implies metals in superwinds do not remain in the IGM for a Hubble time and are more likely to rejoin galaxies. Metal absorbers aligned with Lyman-alpha are examined in detail, finding that the two often trace different phases of gas with the former tracing an inhomogeneous distribution of metals exhibiting turbulence imparted during the outflow phase dissipating on a Hubble timescale. I find this is the first model to self-consistently reproduce the wide range of IGM observables spanning the history of heavy metal production while being consistent with key galaxy observables. The link between star formation and galactic superwinds requires that a successful model of galaxy formation reproduces both the evolution of galaxies and the IGM.

We study specific aspects of the relationship between the stellar content and the intracluster media (ICM) of galaxy clusters. First, we attempt to solve the long-standing difficulty in explaining the highly enriched ICM by including a previously unaccounted for stellar component: the intracluster stars. To determine the relative contributions of galactic and intracluster stars to the enrichment of the intracluster medium (ICM), we present X-ray surface brightness, temperature, and Fe abundance profiles for a set of twelve galaxy clusters for which we have extensive optical photometry. Assuming a standard IMF and simple chemical evolution model scaled to match the present-day cluster early-type SN Ia rate, the stars in the brightest cluster galaxy (BCG) plus the intracluster stars (ICS) generate 31⁺¹¹₋₉%, on average, of the observed ICM Fe within r₅₀₀(∼ 0.6 times r₂₀₀, the virial radius). Because the ICS typically contribute 80% of the BCG+ICS Fe, we conclude that the ICS are significant, yet often neglected, contributors to the ICM Fe within r₅₀₀. However, the BCG+ICS fall short of producing all the Fe, so metal loss from stars in other cluster galaxies must also contribute. By combining the enrichment from intracluster and galactic stars, we can account for all the observed Fe. These models require a galactic metal loss fraction (0.84(−0.14)^(+0.11)) that, while large, is consistent with theoretical models of Fe mass not retained by galactic stars. The SN Ia rates, especially as a function of galaxy environment and redshift, remain a significant source of uncertainty in further constraining the metal loss fraction. Second, we study the effects of ram-pressure stripping on infalling galaxies using a warm molecular hydrogen (H₂) as a tracer by carrying out a Spitzer infrared spectrograph (IRS) survey of four galaxies with signatures of ram-pressure stripping. We have discovered two galaxies, ESO 137-001 and NGC 4522, with warm H₂ tails stretching 20 kpc and 4 kpc in length, respectively. In the case of ESO 137-001 where we measure a warm H₂ mass loss rate of ∼ 2 − 3 M⊙ yr⁻¹, we estimate that the galaxy will lose all of its gas in a single pass through the cluster core. Strong warm H₂ emission is detected in one other galaxy, CGCG 97-073, which a region within its tail that is mainly dominated by H₂ emission. The warm H₂ observed in these three galaxies share similar temperature and column density properties with warm H₂ masses ranging from 10⁶ − 10⁸ M⊙. From a comparison with the SINGS warm H₂ sample, our results indicate that these galaxies experiencing significant ram-pressure stripping show anomalously high warm H₂ emission that cannot be explained purely from star formation. This adds credence to the hypothesis that H₂ within these galaxies is being shock-heated from the interaction with the ICM. We also discover that stripping of warm and hot dust, as measured at 8 μm and 24 μm, is a common feature of the galaxies observed in our sample. In the case of NGC 4522, we capture the turbulent nature of the stripping process. We measure the star formation rates using published Hα and measured 24 μm luminosities for all of our galaxies and find that some of them have suppressed star formation rates compared to similar mass counterparts in the field. We find a possible association between Hα and warm H₂ emission in three of the four galaxies observed. We conclude that the variation of H₂ properties observed in our sample is likely due to the galaxies being in different stages of ram-pressure stripping. Finally, we report on our efforts to improve the performance of the Lochkeed Arizona Infrared Spectrometer (LAIRS), a near-IR, tunable filter imager. We have made significant progress in identifying the sources of key issues such as the a highly asymmetric line profile and the unstable performance of the servo controller at the MMT. Solutions have been implemented for these issues, such as a revised mounting strategy for the tunable filter plates and a completely new controller with higher bandwidth. Significant progress has been made towards resolving these issues, but a few issues remain before LAIRS meets all of its requirements.

Remote determination of the hydrate content of marine sediments remains a challenging problem. In the absence of boreholes, the most commonly used approach involves the measurement of Pwave velocities from seismic experiments. A range of seismic effective medium methods has been developed to interpret these velocities in terms of hydrate content, but uncertainties about the pore-scale distribution of hydrate can lead to large uncertainties in this interpretation. Where borehole geophysical measurements are available, electrical resistivity is widely used as a proxy for hydrate content, and the measurement of resistivity using controlled source electromagnetic methods shows considerable promise. However, resistivity is commonly related to hydrate content using Archie’s law, an empirical relationship with no physical basis that has been shown to fail for hydrate-bearing sediments. We have developed an electrical effective medium method appropriate to hydrate-bearing sediments based on the application of a geometric correction to the Hashin-Shrikman conductive bound, and tested this method by making resistivity measurements on artificial sediments of known porosity. We have adapted our method to deal with anisotropic grains such as clay particles, and combined it with a well-established seismic effective medium method to develop a strategy for estimating the hydrate content of marine sediments based on a combination of seismic and electrical methods. We have applied our approach to borehole geophysical data from Integrated Ocean Drilling Program Expedition 311 on the Vancouver Island margin. Hydrate saturations were determined from resistivity logs by adjusting the geometric factor in areas of the log where hydrate was not present. This value was then used over the entire resistivity log. Hydrate saturations determined using this method match well those determined from direct measurements of the methane content of pressurized cores.

Methane gas hydrates have attracted significant international interest as a potential future energy resource, but also as a geotechnical hazard for offshore operations related to hydrocarbon recovery. In this context, the abilities to detect the presence of hydrate in marine sediments and to quantify the amount of hydrate contained therein, have become increasingly important over the years. Detection and quantification of hydrates are done on the basis of seismic surveys, which measure indirectly the bulk dynamic properties of large volumes of sediment in situ. Seismic data are then interpreted using an effective medium model, which employs theoretical assumptions to relate wave velocities to gas hydrate content of the sediment. Wave velocity can then be used to infer hydrate concentration levels. A host of such effective medium models exists in the literature. Many of these models have been calibrated on and tested on specific sites, and are not readily transferable to other settings. In addition, many models ignore the existence of heterogeneities of the host sediment, or the inhomogeneous distribution of hydrate within it. These, however, are factors that may have a significant impact on the seismic signature of the sediment-hydrate system, and thus on the predicted quantity of hydrate. This paper presents a review of existing effective medium models and identifies general areas for improvement. A new numerical modelling method is outlined that enhances existing effective medium approaches, by taking explicitly into account different hydrate morphologies within the host sediment.

No description available.

Interleukin-3 is a cytokine, which acts on many target cells within the haemopoietic system, often in synergy with the other cytokines. Streptomyces lividans NCIMB 11416/IL3 p002 secreting human interleukin-3 was used as the host organism in this study of improving target protein production. Streptomyces also produces several proteases including extracellular endoprotease that truncate the N-terminus of the recombinant protein. Federal guidelines and regulations banning animal-derived medium components necessitate the refinement or redevelopment of industrial medium formulations. The development of a defined medium without animal products is most desirable for the production of pure and safe biological products. The objective of the proposed research was the development and application of engineering methodology for the development of a defined medium and the analysis and optimization of a bacterial bioprocess for recombinant protein production. The underlying hypothesis is that a significant improvement of target protein productivity is achievable by using appropriate optimization techniques. During the first phase of this study the task was to develop a systematic procedure for the design and optimization of a chemically defined medium. The study aimed at replacing casein peptone in conventional medium for S. lividans with essential amino acids and determining the optimum proportion of the amino acids. To accomplish this, starvation trials with growth limiting amino acids were performed to establish the baseline for the nutritional requirement. The starvation trials revealed that essential amino acids for growth and product formation are amongst the following eight amino acids: Arg, Asn, Asp, Glu, Leu, Met, Phe, and Thr. Following these preliminary experiments, a statistically based experimental method called mixture experiments along with distance-based multivariate analysis revealed that Asp, Leu, Met, and Phe were the essential amino acids. Then, another mixture experiment design known as simplex lattice design was performed and artificial neural networks were employed to obtain the optimum proportions of the essential amino acids. The optimal medium was found to be composed of 56% Asp, 5% Met, and 39% Phe. It was found in previous studies that in complex media, several types of protease are produced during fermentation. Using the defined medium no proteolytic activity was detected in the fermentation broth. The second optimization method was based on metabolic flux analysis. A comprehensive metabolic network was developed for S. lividans. The metabolic network included carbohyderate and amino acid metabolism in both anabolic and catabolic reactions. According to the experimental results, the time course of the fermentation was divided into two phases, Phase E1 and Phase E2. In the first phase amino acids were used as a nitrogen source and in the second phase ammonia was the nitrogen source for growth and product formation. The metabolic network was used to form a set of linear algebraic equations based on the stoichiometry of the reactions by assuming pseudo-steady state for intracellular metabolites. The metabolic flux model consisted of 62 intracellular metabolites and 91 biochemical reactions. Two different objective functions were considered for optimization: maximizing the specific growth rate and minimizing the redox equivalent. A linear programming approach was used for optimizing the objective functions. The proposed model was able to predict the specific growth rate very accurately with a maximum error of 10%. The oxygen uptake rate and carbon dioxide evolution rate were evaluated with maximum error of 27% and 35%, respectively. Sensitivity analysis revealed that amino acid uptake was the growth limiting flux during the Phase E1 of the fermentation. During Phase E2 the uptake rate of ammonia had a significant effect on the specific growth rate. Sensitivity analysis of the specific growth rate and redox potential with respect to the biomass components showed that any additional supply of biomass building blocks (amino acids, nucleotides) would not significantly affect the specific growth rate and redox potential production as well as the calculated flux pattern.

Untersucht wurde die mögliche Rolle von Adenosin-5´-Triphosphat (ATP) als extrazelluläres Signalmolekül im Neostriatum der Ratte. Zum Einsatz kam die patch-clamp Methode, adaptiert für Ableitungen aus akuten Hirnschnitten. Bereits bekannt war, dass ATP exzitatorische postsynaptische Ströme an GABAergen, striatalen Projektionsneuronen („medium spiny“ Neurone) hemmen konnte. Nun sollten die verantwortlichen Mechanismen hinter diesem Effekt aufgeklärt werden. Es zeigte sich, dass exogen zugeführtes ATP zunächst zu Adenosin metabolisiert werden musste, um seine Wirkung ausüben zu können. Ein Teil dieses Effektes war, vermittelt über präsynaptische Adenosin A1-Rezeptoren, einer Hemmung der striatalen Glutamat-Freisetzung geschuldet. Neu war, dass auch die „medium spiny“ Neurone selbst funktionelle A1-Rezeptoren exprimierten. Aktiviert durch lokal gebildetes Adenosin vermittelten diese eine Hemmung der Leitfähigkeit von Glutamat-Rezeptoren des N-Methyl-D-Aspartat (NMDA) Subtyps. Unter physiologischen Bedingungen mag dieser Mechanismus der Begrenzung der Informationsweiterleitung über die GABAergen Projektionsneurone dienen. Striataler Glutamat-Exzess mit Überaktivierung von NMDA-Rezeptoren ist ein Charakteristikum der Huntington´schen Erkrankung. Eine Adressierung der A1 Rezeptoren als therapeutische Option im Rahmen dieser Basalganglienerkrankung scheint daher prinzipiell möglich.

Тема моей работы магистра Герой и среда в раннем творчестве Л. Н. Толстого. В раннем творчестве Л. Н. Толстой особенное внимание уделяет раскрытию человека в необычных условиях жизни. В связи с этим, особое з��ачение приобретает аспект взаимоотношения человека со средой. В нашей работе магистра взято пять произведений раннего творчества Л. Н. Толстого, в них различные герои, различная среда, различные развязки влияния ��реды на характеры, судьбы героев. В рассказе «Записки маркёра» изображена гибель героя в порочной среде, в повести «Утро помещика» видим неудавшиеся попытки героя изменить среду, в рассказе «Люцерн» герой сталкивается со средой людей высокой цивилизации, в повести «Семейное счастье» героиня, покинув деревенскую среду, пытается найти счастье в светской среде, но разочаровывается в ней и с мужем возвращается обратно в деревню, в повести «Казаки» попытки героя найти счастье в экзотической среде всё же заканчиваются неудачей. В перечисленных произведениях раннего Толстого, герои не находят того, чего искали, чего надеялись, они терпят неудачу, это обусловлено как субъективными свойствами их самих, так и влиянием среды. / Darbo įžangoje trumpai apibūdinama tai, kaip ankstyvoji Tolstojaus kūryba buvo vertinama jo metų literatūros kritikų ir vėlesnių tyrinėtojų darbuose. Tema „Herojus ir aplinka ankstyvojoje L. Tolstojaus kūryboje“ nebuvo išsamiai nagrinėta darbuose apie rašytoją. Todėl mūsų tikslas – išnagrinėti ją remiantis penkiais rašytojo kūriniais, kurie priskiriami ankstyvajam kūrybos periodui. Pagrindinė darbo dalis susideda iš penkių skyrių: I. Skyrius. Herojaus žuvimas ydingoje aplinkoje ( „Markerio užrašai“ ); II. Skyrius. Herojaus pastangos pakeisti aplinką ( „Dvarininko rytas“ ); III. Skyrius. Herojus aukštos civilizacijos žmonių aplinkoje ( „Liucernas“ ); IV. Skyrius. Patrauklios aplinkos pavojus ( „Šeimyninė laimė“); V. Skyrius. Herojaus pastangos atrasti laimę egzotiškoje aplinkoje ( „Kazokai“ ). Pirmame kūrinyje „Markerio užrašuose“ pagrindinis herojus Nechliudovas, jaunas, turtingas žemvaldys neturėjo jokio užsiėmimo, gyvenimo tikslo, todėl atvykęs į Peterburgą pasidavė degradavusios aplinkos įtakai, kuri jį galiausiai ir įstūmė į pražūtį. Lošėjo aistra užvaldė herojų, jis neteko visko, ką turėjo. Jaunuolis pražudė ne tik save. Dėl Nechliudovo kaltės sunkioje padėtyje atsidūrė ir jo valstiečiai. Pamatęs savo kaip žmogaus visišką smukimą ir negalėdamas išbristi iš purvo, herojus nusižudė. Apsakyme „Dvarininko rytas“... [toliau žr. visą tekstą] / An introduction is a short description telling about the critics evaluation of the works of Leo Tolstoy. The theme The hero and the medium in the early works of Leo Tolstoy hasn’t received a detailed investigation yet. Consequently, our aim is to analyze the theme on five early writer’s works basis. My work’s background consists of five chapters: I. Chapter. The death of the hero in the faulty medium. («Записки маркёра»); II. Chapter. The attempts of the hero to change the medium. («Утро помещика»); III. Chapter. The hero surrounded by the people of advanced civilization. («Люцерн»); IV. Chapter. The danger of the attractive medium. («Семейное счастье»); V. Chapter. The attempts of the hero to find happiness in the exotic medium. («Казаки»). The main hero of the first work is young and rich landlord. He hadn’t any occupation, any aim of life. Due to this reason, the hero had been influenced by the faulty medium, which caused his death after the arrival in Saint-Peterburg. The hero was enslaved by the gambler’s passion, he lost everything he had. Such hero’s actions were harmful not only to himself but also to his peasants. Admitting any possibility to change his life and hopeless about the future he committed suicide. The main hero of the second work gives up his studies and goes to the countryside in order to help peasants. He isn’t able to fulfill his dreams. People disbelieved in good hero’s intentions. Even young landlord didn’t know... [to full text]