Constraining holographic inflation with WMAP

In a class of recently proposed models, the early universe is strongly coupled and described holographically by a three-dimensional, weakly coupled, super-renormalizable quantum field theory. This scenario leads to a power spectrum of scalar perturbations that differs from the usual empirical LCDM form and the predictions of generic models of single field, slow roll inflation. This spectrum is characterized by two parameters: an amplitude, and a parameter g related to the coupling constant of the dual theory. We estimate these parameters, using WMAP and other astrophysical data. We compute Bayesian evidence for both the holographic model and standard LCDM and find that their difference is not significant, although LCDM provides a somewhat better fit to the data. However, it appears that Planck will permit a definitive test of this holographic scenario.Comment: 24 pages, 9 figs, published versio

Holographic predictions for cosmological 3-point functions

We present the holographic predictions for cosmological 3-point correlators, involving both scalar and tensor modes, for a universe which started in a non-geometric holographic phase. Holographic formulae relate the cosmological 3-point functions to stress tensor correlation functions of a holographically dual three-dimensional non-gravitational QFT. We compute these correlators at 1-loop order for a theory containing massless scalars, fermions and gauge fields, and present an extensive analysis of the constraints due to Ward identities showing that they uniquely determine the correlators up to a few constants. We define shapes for all cosmological bispectra and compare the holographic shapes to the slow-roll ones, finding that some are distinguishable while others, perhaps surprisingly, are not.Comment: 51pp; 4 fig

The NYU inverse swept wing code

An inverse swept wing code is described that is based on the widely used transonic flow program FLO22. The new code incorporates a free boundary algorithm permitting the pressure distribution to be prescribed over a portion of the wing surface. A special routine is included to calculate the wave drag, which can be minimized in its dependence on the pressure distribution. An alternate formulation of the boundary condition at infinity was introduced to enhance the speed and accuracy of the code. A FORTRAN listing of the code and a listing of a sample run are presented. There is also a user's manual as well as glossaries of input and output parameters

An overview of palaeomagnetic chronology with special reference to the South African hominid sites

Main articleThe phenomena of secular variation, polarity reversals and apparent polar wander are discussed. The calibration of each of these phenomena for use in palaeomagnetic chronology is outlined and the use of each of these calibrated scales for dating is briefly explained. A successful application of the polarity reversal dating technique is presented as an example of the potential for palaeomagnetic chronology in South Africa. In this example it is shown that the age of the important Member 3 in Makapan is about 3 My. It is concluded that palaeomagnetic chronology has a vast potential in South Africa ; a palaeomagnetic laboratory specifically oriented to chronological problems would be extremely valuable.Non

Gating of high-mobility InAs metamorphic heterostructures

We investigate the performance of gate-defined devices fabricated on high mobility InAs metamorphic heterostructures. We find that heterostructures capped with In$_{0.75}$Ga$_{0.25}$As often show signs of parallel conduction due to proximity of their surface Fermi level to the conduction band minimum. Here, we introduce a technique that can be used to estimate the density of this surface charge that involves cool-downs from room temperature under gate bias. We have been able to remove the parallel conduction under high positive bias, but achieving full depletion has proven difficult. We find that by using In$_{0.75}$Al$_{0.25}$As as the barrier without an In$_{0.75}$Ga$_{0.25}$As capping, a drastic reduction in parallel conduction can be achieved. Our studies show that this does not change the transport properties of the quantum well significantly. We achieved full depletion in InAlAs capped heterostructures with non-hysteretic gating response suitable for fabrication of gate-defined mesoscopic devices

How a National Carbon Policy Could Affect Grain Variety Selection: The Case of Rice in Arkansas

This study conducts a life cycle assessment (LCA) of carbon emissions and estimates the carbon sequestered in 14 commonly sown rice varieties across the Arkansas Delta. Given the uncertainty regarding future carbon legislation, and increased consumer and industry demand for “greener” products, this study estimates how potential carbon policies would affect rice cultivar selection Hybrid rice varieties, given their higher yield and higher yield per unit of green house gas (GHG) emission, are better positioned to take advantage of any increase in consumer demand for “greener” products and/or absorb any government policy better than conventional rice cultivars.Rice, Carbon Policy, Cap and Trade, Carbon Offset, Agricultural and Food Policy, Crop Production/Industries, Environmental Economics and Policy, Q52, Q54, Q58,

Macroeconomic models of consumer demand for consumer packaged goods in Asia

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 90-92).CPGCo, a global manufacturer of consumer packaged goods, has had tremendous difficulty in producing accurate forecasts for its products in developing markets. The problem was especially apparent during the global economic crisis in 2008, which caused demand for its products to become highly volatile. Its troubles have been aggravated by its long forecasting horizon, as it has not been able to adjust quickly enough to rapid market shifts due to fluctuations in various macroeconomic indicators. As a result, CPGCo faces heavy stockouts and excess inventories. This thesis explores the suitability of using macroeconomic indicators to forecast consumer demand for three developing countries in Asia as well as three separate product segments. A total of 27 macroeconomic models are constructed using stepwise multiple linear regression analysis employing three separate dependent variables: the firm's monthly wholesale shipment volume, retail market share by volume, and retail sales. The world oil price and country-specific exchange rates, stock indexes, interest rates, consumer price indexes, and consumer confidence indicators are used as independent variables. With our models, we are capable of producing extremely accurate forecasts for a small sample set with errors at or below 7.2%. Our findings also indicate that the consumer price index has the most influence on consumer demand, appearing in 81% of our models; thus, we recommend that CPGCo tracks the consumer price index of each country to complement its current forecasting processes.by Jonathan Mau and Bryan P. McFadden.M.Eng.in Logistic

Effective Actions for Heterotic M-Theory

We discuss the moduli space approximation for heterotic M-theory, both for the minimal case of two boundary branes only, and when a bulk brane is included. The resulting effective actions may be used to describe the cosmological dynamics in the regime where the branes are moving slowly, away from singularities. We make use of the recently derived colliding branes solution to determine the global structure of moduli space, finding a boundary at which the trajectories undergo a hard wall reflection. This has important consequences for the allowed moduli space trajectories, and for the behaviour of cosmological perturbations in the model.Comment: 21 pages, 4 figures. References added and some discussions clarifie