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Rosetta is a European spacecraft that will rendevouz with andfollow the comet 67P/Churyumov-Gerasimenko from 2014 to 2015. Among other instruments are two Langmuir probes that measure certain plasma parameters. This study aims to describe the photoemssionon Rosetta and in particular on the Langmuir probes. More than 7800 bias voltage sweeps were analyzed and parameters such as photosaturationcurrent, spacecraft potential, photoelectron temperature and offset current were calculated from these sweeps. It is found that the photoemission is stronger on Probe 1 than Probe 2. The photosaturation currents for dierent mission phases align rather well when normalized to distance to the Sun and the solar activity, when correcting for the offset currents found on the probes the alignment became even better. The typical electron density in the photoelectron cloud is 25 cm^-3 at 1 AU and the electron temperature varies from 1 - 2 eV.

The Rosetta spacecraft is on route to rendezvous with the comet 67P/ Churyomov-Gerasimenko. One of the instruments onboard is the Langmuir probe instrument (LAP) developed by the Swedish Institute of Space Physics. The LAP includes two spherical probes used to measure a number of properties of the surrounding plasma. One measured property is the plasma density for which the spacecraft potential is a good proxy. By the determining the potential between spacecraft and Langmuir probe, the spacecraft potential can be measured. But such measurements are sometimes disturbed by the potential from the spacecraft itself, the influence from photoemitted electrons and the solar wind wake behind Rosetta. In order to correct for the errors caused by spacecraft-plasma interaction in the solar wind a model depending on the spacecraft (and Langmuir probe) orientation is developed. The data is obtained from three-dimensional simulations of Rosetta, with varying plasma parameters, using the software SPIS (Spacecraft Plasma Interaction System). Least squares fitting with a set of basis functions then provide the input for a parametric modelling. The developed model makes it possible to estimate the influence of each of the disturbing effects. The developed model gives good fits to data obtained in SPIS simulations. The two angular dependent factors, modelling perturbation on potential measurements caused by photoelectrons and wake effects, show errors below the 100 mV level in all cases. The model describing the influence from spacecraft potential is slightly less accurate, with errors at or below the 400 mV level in all relevant cases.

By modelling and simulating the ESA spacecraft Rosetta in a plasma with solar wind parameters, and simultaneously simulating a particle detection experiment of Langmuir probe voltage sweep type using the ESA open source software SPIS Science, we investigate the features of Rosetta’s envi- ronment in the solar wind and the e↵ect of photoemission from the space- craft on the measurements made by the Langmuir Probe instrument on board Rosetta. For a 10 V positively charged spacecraft and Maxwellian distributed photoelectron emission with photoelectron temperature, Tf = 2 eV in a plasma of typical 1 AU solar wind parameters: ne = 5 ⇥ 106 m3, vSW = 4 ⇥ 105 m/s, Te = 12 eV, Tion = 5 eV, we detect a floating potential of 6.4 (± 0.2) V at Langmuir probe 1. Two models used in literature on photoemission was used and compared and we report a clear preference to the Maxwellian energy distribution of photoelectrons from a point source model with our simulation result.

Enzyme design is a steadily growing field of computational chemistry, but its successes are limited by the current available knowledge and application of enzyme conformational dynamics. In this work a series of FTIR and 2D IR spectroscopic methods, for observing the conformational dynamics of an enzymatic active site and its surrounding residues, are characterized. The enzyme model system for these studies is the promiscuous ene-reductase from Pyrococcus horikoshii (PhENR) which is capable of binding substrates in multiple orientations. In one method, the spectral lineshape of an aryl-nitrile substrate-analog vibrational label is analyzed using a frequency fluctuation correlation function (FFCF) and compared to the lineshape of a corresponding aryl-azide label. This analysis revealed dynamic and electrostatic active site anisotropy which may influence substrate catalysis. The second method utilizes the intramolecular vibrations of the enzymatic cofactor, flavin mononucleotide (FMN), which is shown to be sensitive to electric field changes associated with substrate binding. The final method places a site-specific nonnatural amino acid containing an azide probe within the enzyme’s hydrophobic core. Additionally, a double-mutant cycle was identified via a common design program, the Rosetta Modeling Suite, and used to analyze the effects of mutation on enzyme dynamics. Altogether, these methods demonstrate the ability of 2D IR spectroscopy to observe enzyme conformational dynamics. Application of these methods to various other enzyme model systems should provide valuable insight for the improvement of future dynamic enzyme design protocols.

`The Rosetta Stone Language Library` is a language learning software developed by the American company Fairfield Language Technologies which allows users to learn a foreign language with their computer without the aid of an instructor. The program promises its users they can learn a language faster and with more ease than ever before, without having to learn vocabulary or grammatical rules. Once having completed Levels I and II, learners should be able to make themselves understood in the new language using a basic vocabulary of roughly 3000 words. Both these levels are to be completed within a time frame of one to two years, and the results should be the equivalent of five years of conventional school instruction. Since 1993, a Swahili language course has been featured in The Rosetta Stone for which only Level I is currently available. With regard to the Swahili course, it must be asked if this design can work with a class language just as it does with an Indo-European gender language. The second question addresses the cultural adequacy of the contexts, or more specifically, of cultural knowledge, which must not be excluded from modern language instruction.

Zugl.: Braunschweig, Techn. Univ., Diss., 2008

L'expérience Comet Nucleus Sounding par Radio-wave Transmission (CONSERT / Rosetta) a été conçu pour scanner l'intérieur de la comète 67P / Churyumov-Gerasimenko. Cet instrument se compose de deux parties: l'une à bord de Rosetta et l'autre à bord de Philae. Les données disponibles à partir des tests de fonctionnement et d’étalonnage ont permis de faire une calibration de l’instrument de bout à bout. Cette calibration a permis de corriger le déséquilibre d’amplitude à 5%, de la puissance de sortie et de construire une loi de compensation pour les différents modèles de vol et de recharge. Celui-ci a augmenté la précession de l’AGC et gain système et enfin nous avons estimé le délai engendré par les filtres et l’électronique du système pour les différents modèles. Les résultats obtenus sur la calibration des données sur chaque modèle réduiront, en conséquence, les erreurs d’estimation. Enfin, l’étalonnage de CONSER a beaucoup contribué à améliorer les mesures effectuées lors de l’atterrissage du Philae sur la comète. / The Comet Nucleus Sounding Experiment by Radio-wave Transmission (CONSERT / Rosetta) was designed to scan the interior of the comet 67P / Churyumov-Gerasimenko. This instrument consists of two parts:one on board of Rosetta and the other on board of Philae. The data available from operational and calibration tests allowed a end-to-end calibration of the instrument. This calibration enabled to correct the amplitude imbalance at 5%, of the output power and to build a compensation law for the different models of flight and recharging. This increased the precession of the AGC and gain systemand finally we estimated the delay generated by the filters and electronics system for the different models. The results obtained on the calibration of the data on each model will consequently reduce the estimation errors.Finally, the calibration of CONSER contributed significantly to improve the measurements made during the landing of the Philae on the comet.

This paper examines the neutral coma of comet 67P/Churyumov–Gerasimenko by using measurements of charged particles (water ions) and tracing them back to their place of ionisation. The measurements were taken from Rosetta’s Ion Composition Analyser. The simulations made use of an existing program which traces particles forward, which was changed to trace particles backwards, with new conditions for terminating the simulation. Two types of simulations were made. The first type is referred to as ”one-day simulations”. In these, simulations are made using data from a single occasion, with nine occasions studied per selected day. The days were selected so that the spacecraft was in different positions in relation to the comet. The second is referred to as the ”full-hemisphere” simulation. In this simulation, data from all usable days are used to produce an image of the hemisphere facing the Sun. The full-hemisphere simulation suffers from lack of simultaneous measurements, and indeed it is impossible to obtain in-situ measurements at all positions at once. Both simulations could be improved using more precise models, which could not be done within the allotted time of this work.

Amas Repertory Theatre was founded in 1969 by Rosetta LeNoire, an African American actress who pursued a mission of developing original musicals while practicing interracial casting. The company's most successful show was Bubbling Brown Sugar (1975). Throughout Amas's history LeNoire's complicated perspective on what constituted discrimination sometimes caused her casting choices to be questioned. LeNoire believed in a colorblind theatre and society, however, as the decades passed, her colorblind perspective was challenged by neo-conservative philosophy which states that in a colorblind society no particular group should receive any more privilege than another. This definition of colorblind is used to justify conservative efforts to eliminate affirmative action and undermine race conscious legislation. In the late 1990s, at her retirement, LeNoire, who always believed that color did not matter, turned her theatre over to white leadership, who still operate Amas today. At that point, Amas changed from a company that had, from its founding, been considered to be a black theatre to one that is now white. As the history of Amas unfolds, my study examines the complex politics surrounding the concept of colorblindness. Efforts by Actors' Equity to promote interracial or, as it is often called, nontraditional casting are also investigated as well as the conservative backlash against race conscious policies, particularly during and after the administration of Ronald Reagan. In the present day Amas practices a multicultural mission, however, as my dissertation examines the company's programming decisions as well as its perspective on race, Amas is revealed to be an example of how white operated theatres, even if unintentionally, through the agency of white power and privilege, are affected by the same institutional racism that permeates American society. My dissertation then challenges Amas and other theatres to take responsibility for staying fully aware of the racially charged issues and tensions that exist in America today. When theatre professionals seek out and are committed to engaging in open dialogue on race they are in a stronger position to make knowledgeable decisions regarding the representation of race on stage.