7,828 research outputs found
Hyperbolic Voronoi Percolation
In this thesis, we studied the behaviour of the critical probability for percolation of Voronoi cells in the hyperbolic plane. There are profound differences between this model of percolation in the hyperbolic plane and the Euclidean plane. Most notably, the critical probability is a function of the intensity
Cigarette Taxes and the Social Market
Previous researchers have argued that the social market for cigarettes insulates its participants from policies designed to curb youth smoking. Using state Youth Risk Behavior Survey data, we examine whether recent changes in state cigarette taxes affected how young smokers obtained their cigarettes. Our estimates suggest that tax increases reduce youth smoking participation primarily through their effect on third-party purchase, although there is evidence that they are negatively related to borrowing among younger teenagers and negatively related to direct purchase among older teenagers.youth smoking, cigarette taxes
Evaluation of Corn Condensed Distillers Solubles in Beef Cattle Diets and Grazing Double-Cropped Forages Following Corn Harvest
Corn condensed distillers solubles (CDS) is a protein and energy dense by-product from dry-milled production of ethanol. Recent oil extraction has posed modifications to the nutrient profile of CDS, suggesting that de-oiled CDS needs to be re-evaluated in beef cattle diets. Three experiments were conducted to evaluate the effects of CDS in high-concentrate diets, forage-based diets, as well as evaluate the effects of CDS on diet digestibility and rumen fermentation parameters in forage-based diets. Feeding CDS in high-concentrate diets up to 20% of the diet DM or in combination with wet distillers grains plus solubles (WDGS) improved performance and resulted in greater energy value compared to corn. Feeding values of 20% CDS or the combination of 16% CDS and 20% WDGS were 147 and 129% compared to corn, respectively. Feeding CDS in forage-based diets up to 40% of the diet DM diminished performance and resulted in a lesser energy value compared to corn. Linear decreases were observed in total tract digestibility of NDF and the acetate to propionate ratio in rumen fluid.
Double-cropped forages following corn harvest offer livestock producers an opportunity to extend their grazing season on high quality forage in the fall. Additionally, crop producers may benefit from the implementation of grazing animals due to added soil nutrients and removal of residue. Therefore, an experiment was conducted to evaluate the effects of double-cropped oats following corn silage (CS) or high-moisture corn (HMC) on calf gains, forage production, and subsequent cash crop yields. Oats seeded after CS produced more forage biomass than oats seeded after HMC. Both treatments produced high quality oats (22% CP, 39% NDF, and 24% ADF averaged across treatments). Calf gains were greater grazing oats following CS compared to HMC at 1.10 and 0.84 kg / d, respectively. Across 1-yr of data, subsequent cash crop yields were not different for HMC and soybeans with increased CS yields in both covered/grazed and non-covered/non-grazed treatments compared to the covered/non-grazed treatment.
Advisor: James C. MacDonal
Temperature and Polarization CMB Maps from Primordial non-Gaussianities of the Local Type
The forthcoming Planck experiment will provide high sensitivity polarization
measurements that will allow us to further tighten the f_NL bounds from the
temperature data. Monte Carlo simulations of non-Gaussian CMB maps have been
used as a fundamental tool to characterize non-Gaussian signatures in the data,
as they allow us to calibrate any statistical estimators and understand the
effect of systematics, foregrounds and other contaminants. We describe an
algorithm to generate high-angular resolution simulations of non-Gaussian CMB
maps in temperature and polarization. We consider non-Gaussianities of the
local type, for which the level of non-Gaussianity is defined by the
dimensionless parameter, f_NL. We then apply the temperature and polarization
fast cubic statistics recently developed by Yadav et al. to a set of
non-Gaussian temperature and polarization simulations. We compare our results
to theoretical expectations based on a Fisher matrix analysis, test the
unbiasedness of the estimator, and study the dependence of the error bars on
f_NL. All our results are in very good agreement with theoretical predictions,
thus confirming the reliability of both the simulation algorithm and the fast
cubic temperature and polarization estimator.Comment: 14 pages, 9 figures, revised version accepted by PRD, minor changes
and acknowledgements adde
The critical probability for Voronoi percolation in the hyperbolic plane tends to 1/2
We consider percolation on the Voronoi tessellation generated by a
homogeneous Poisson point process on the hyperbolic plane. We show that the
critical probability for the existence of an infinite cluster tends to as
the intensity of the Poisson process tends to infinity. This confirms a
conjecture of Benjamini and Schramm.Comment: 15 pages, 6 figures, to be published in Random Structures and
Algorithms, very minor corrections since the last versio
Poisson-Voronoi percolation in the hyperbolic plane with small intensities
We consider percolation on the Voronoi tessellation generated by a
homogeneous Poisson point process on the hyperbolic plane. We show that the
critical probability for the existence of an infinite cluster is asymptotically
equal to as This answers a question of Benjamini
and Schramm.Comment: 70 pages, 11 figures, various corrections made compared to the last
versio
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