Bubble Universe Dynamics After Free Passage

We consider bubble collisions in single scalar field theories with multiple vacua. Recent work has argued that at sufficiently high impact velocities, collisions between such bubble vacua are governed by 'free passage' dynamics in which field interactions can be ignored during the collision, providing a systematic process for populating local minima without quantum nucleation. We focus on the time period that follows the bubble collision and provide evidence that, for certain potentials, interactions can drive significant deviations from the free-passage bubble profile, thwarting the production of bubbles with different field values.Comment: 21pages, 8 figures, Revised version modified to include Acknowledgements sectio

Exploring the String Landscape: The Dynamics, Statistics, and Cosmology of Parallel Worlds

This dissertation explores various facets of the low-energy solutions in string theory known as the string landscape. Three separate questions are addressed - the tunneling dynamics between these vacua, the statistics of their location in moduli space, and the potential realization of slow-roll inflation in the flux potentials generated in string theory. We find that the tunneling transitions that occur between a certain class of supersymmetric vacua related to each other via monodromies around the conifold point are sensitive to the details of warping in the near-conifold regime. We also study the impact of warping on the distribution of vacua near the conifold and determine that while previous work has concluded that the conifold point acts as an accumulation point for vacua, warping highly dilutes the distribution in precisely this regime. Finally we investigate a novel form of inflation dubbed spiral inflation to see if it can be realized near the conifold point. We conclude that for our particular models, spiral inflation seems to rely on a de Sitter-like vacuum energy. As a result, whenever spiral inflation is realized, the inflation is actually driven by a vacuum energy

Warped Vacuum Statistics

We consider the effect of warping on the distribution of type IIB flux vacua constructed with Calabi-Yau orientifolds. We derive an analytical form of the distribution that incorporates warping and find close agreement with the results of a Monte Carlo enumeration of vacua. Compared with calculations that neglect warping, we find that for any finite volume compactification, the density of vacua is highly diluted in close proximity to the conifold point, with a steep drop-off within a critical distance.Comment: 30 pages, 2 figure

Good practices for estimating area and assessing accuracy of land change

The remote sensing science and application communities have developed increasingly reliable, consistent, and robust approaches for capturing land dynamics to meet a range of information needs. Statistically robust and transparent approaches for assessing accuracy and estimating area of change are critical to ensure the integrity of land change information. We provide practitioners with a set of “good practice” recommendations for designing and implementing an accuracy assessment of a change map and estimating area based on the reference sample data. The good practice recommendations address the three major components: sampling design, response design and analysis. The primary good practice recommendations for assessing accuracy and estimating area are: (i) implement a probability sampling design that is chosen to achieve the priority objectives of accuracy and area estimation while also satisfying practical constraints such as cost and available sources of reference data; (ii) implement a response design protocol that is based on reference data sources that provide sufficient spatial and temporal representation to accurately label each unit in the sample (i.e., the “reference classification” will be considerably more accurate than the map classification being evaluated); (iii) implement an analysis that is consistent with the sampling design and response design protocols; (iv) summarize the accuracy assessment by reporting the estimated error matrix in terms of proportion of area and estimates of overall accuracy, user's accuracy (or commission error), and producer's accuracy (or omission error); (v) estimate area of classes (e.g., types of change such as wetland loss or types of persistence such as stable forest) based on the reference classification of the sample units; (vi) quantify uncertainty by reporting confidence intervals for accuracy and area parameters; (vii) evaluate variability and potential error in the reference classification; and (viii) document deviations from good practice that may substantially affect the results. An example application is provided to illustrate the recommended process

Modified Einstein Hilbert Action and the Resulting Field Equations

We begin by reviewing special and general relativity in such a way as to smoothly transition into current research. We present the variational formalism of general relativity as well as the extension into the palatini formalism. This allows us to develop a theory on a metric affine manifold rather than the standard manifold in general relativity. We present a generalized action intended to replace the Einstein Hilbert action in general relativity and derive some consequences thereof. The modified field equations are derived by varying this action using the Palatini approach. The corresponding differential equations are solved thereby establishing the equivalence between the modified action and the standard action with a cosmological constant. Furthermore the metric due to a spherically symmetric distribution of mass is found and applied in calculating the bending of light in the curved space. It is deduced that no difference between the modified action and the original Einstein Hilbert action is observed thereby implying that the experiment involving the bending of light around the sun in 1919 in no way distinguishes between our modification and the original approach by Einstein and Hilbert

Competiveness among apparel manufacturers in Istanbul : An industry analysis

This paper is the result of a minor field study conducted in Istanbul, Turkey, during the period of November and December 2007. The purpose of the paper is to investigate the current business environment for apparel manufacturing in Istanbul. Research was carried out through an industry analysis in terms of competition and potential future development for apparel manufacturers. The research has been carried out through interviews with actors related to the apparel manufacturing segment. Interviewees include five manufacturers, two sourcing agents, one trade organization and one professor with research in the area. Our findings concerning the business environment are based on Michael E. Porters theoretical framework on “How Competitive Forces Shape Strategy”. In the case of Turkish apparel manufacturers this paper concludes how the barriers of entry for new actors are high, unless integrating forward. Additionally in general terms the suppliers have a weak bargaining position while customers are relatively strong in the bargaining process. The rivalry among apparel manufacturers is low, but it can be stated how less differentiated manufacturer experience significant higher level of rivalry. Further on this paper also concludes how these factors not are affected by any substitute products, much due to the broad scope of the study. In respect to these factors a general strategy used by apparel manufactures has been identified as they try to affect the balance of these competitive forces through e.g. differentiation and vertical integration