Tracking ocean wave spectrum from SAR images

An end to end algorithm for recovery of ocean wave spectral peaks from Synthetic Aperture Radar (SAR) images is described. Current approaches allow precisions of 1 percent in wave number, and 0.6 deg in direction

Gravitational waves in preheating

We study the evolution of gravitational waves through the preheating era that follows inflation. The oscillating inflaton drives parametric resonant growth of scalar field fluctuations, and although super-Hubble tensor modes are not strongly amplified, they do carry an imprint of preheating. This is clearly seen in the Weyl tensor, which provides a covariant description of gravitational waves.Comment: 8 pages, 8 figures, Revte

The Formation of Star Clusters II: 3D Simulations of Magnetohydrodynamic Turbulence in Molecular Clouds

(Abridged) We present a series of decaying turbulence simulations that represent a cluster-forming clump within a molecular cloud, investigating the role of magnetic fields on the formation of potential star-forming cores. We present an exhaustive analysis of numerical data from these simulations that includes a compilation of all of the distributions of physical properties that characterize bound cores - including their masses, radii, mean densities, angular momenta, spins, magnetizations, and mass-to-flux ratios. We also present line maps of our models that can be compared with observations. Our simulations range between 5-30 Jeans masses of gas, and are representative of molecular cloud clumps with masses between 100-1000 solar masses. The cores have mass-to-flux ratios that are generally less than that of the original cloud, and so a cloud that is initially highly supercritical can produce cores that are slightly supercritical, similar to that seen by Zeeman measurements of molecular cloud cores. Clouds that are initially only slightly supercritical will instead collapse along the field lines into sheets, and the cores that form as these sheets fragment have a different mass spectrum than what is observed. The spin rates of these cores suggests that subsequent fragmentation into multiple systems is likely. The sizes of the bound cores that are produced are typically 0.02-0.2 pc and have densities in the range 10^4-10^5 cm^{-3} in agreement with observational surveys. Finally, our numerical data allow us to test theoretical models of the mass spectrum of cores, such as the turbulent fragmentation picture of Padoan-Nordlund. We find that while this model gets the shape of the core mass spectrum reasonably well, it fails to predict the peak mass in the core mass spectrum.Comment: Accepted by MNRAS. 28 pages, 16 figures. Substantial revision since last versio

FEASIBILITY OF AN OKLAHOMA FRESH GREENS AND COWPEAS PACKING COOPERATIVE

Oklahoma's green producers are not benefiting from a growing fresh market. In order to seize the opportunities offered by the growing fresh market for leafy greens, investment in packing facilities have been evaluated. To make use of these facilities during summer months, the addition of a cowpea shelling enterprise is considered. A business plan for a new generation cooperative is estimated using an updated version of "The Packing Simulation Model" (PACKSIM) The business associates PACKSIM with @RISK®, to incorporate risks in the financial analysis.Agribusiness,

Why the crime drop? Why crime rates fall and why they don’t

The ‘crime drop’ is the most important criminological phenomenon of modern times. In North America, Europe, and Australasia, many common crimes have fallen by half or more since the early 1990s, albeit with variation in the specifics. Seventeen explanations are examined here including demographics, policing, imprisonment, drug markets and lead poisoning. Some have been falsified, some lack evidence, some are inconsistent with the evidence, and some claim a minor contribution at most. Pioneering research that developed explanations only relevant to the United States now appears, with the benefit of hindsight, somewhat parochial. Sixteen of the seventeen hypotheses fail one or more of four evidence-based standardized tests on which they are assessed. The one that passes is the security hypothesis, underpinned by crime opportunity theories. Here there is strong evidence from four countries that vehicle theft fell due to more and better security, and mounting evidence that improved security was critical in reducing burglary and other acquisitive crime. Many crime types are inter-related, while most criminal careers are dominated by property crime, so removing these volume crimes might be expected to reduce violence. The policy implication of the security hypothesis is that governments should promote regulation and incentives to promote designing-out crime and crime-proofing for the remaining common crimes plus new and emerging crime types

Signature dish: triangulation from data signatures to examine the role of security in falling crime

This article describes realist evaluation research combining data signatures and theories of causal mechanism as a means of shedding light on why crime has declined in recent years. A data signature is an empirical indicator of how or why something has occurred. The use of multiple signatures – a ‘dish’ – from different angles and contexts can, if they point in the same direction, result in a form of triangulation that reduces the chance of interpretive error. The signatures identified strongly suggest that more and better security played a key role in the global 'crime drop', and in so doing, they rebut rival hypotheses

Income disparities of burglary risk and security availability during the crime drop. British Journal of Criminology, 51(2), 296-313.

In the past fifteen years volume crimes dropped substantially in most countries with reliable crime trend estimates. In England and Wales domestic burglary fell by 58% between 1995 and 2008/09, the trend levelling off after 2005/6. Wider use of more and better security arguably contributed to these drops. The availability of enhanced and especially basic security increased between 1997 and 2005/06, while burglary risk fell for all population income groups. Considering, however, the financial cost of burglary protection devices it is not surprising that enhanced security continues to be more accessible to better off households. In 2005/06 the most affluent households were 60% more likely to have such devices compared to the poorest. This is consistent with the finding that nationally burglary drops have occurred least amongst the poorest segments of population. The better off continue to benefit most in terms of crime protection: burglary risk differentials between the lowest and all other income groups widened during the decade up to 2005/06. Security Impact Assessment Tool analysis however shows that enhanced security confers greatest burglary protection for those who can least afforded it. These results suggest that making enhanced security available to the poorest would further reduce national burglary rates