Longitudinal Momentum Mining of Beam Particles in a Storage Ring

I describe a new scheme for selectively isolating high density low longitudinal emittance beam particles in a storage ring from the rest of the beam without emittance dilution. I discuss the general principle of the method, called longitudinal momentum mining, beam dynamics simulations and results of beam experiments. Multi-particle beam dynamics simulations applied to the Fermilab 8 GeV Recycler (a storage ring) convincingly validate the concepts and feasibility of the method, which I have demonstrated with beam experiments in the Recycler. The method presented here is the first of its kind.Comment: 11 pages, 3 figure

Police Vehicle Searches and Racial Profiling: An Empirical Study

In 1981, the U.S. Supreme Court held in New York v. Belton that police officers could lawfully search virtually anywhere in a vehicle without a warrant after the arrest of any occupant in the vehicle. Then, in 2009, the Court reversed course in Arizona v. Gant, holding that police could only engage in vehicle searches after such arrests in a smaller number of extenuating circumstances. This series of cases became a flash point for the broader debate about the regulation of policing. Law enforcement groups argued that administratively complex rules, like those established in Gant, risk officer safety. But some scholars and civil rights activists worried that by giving police officers wider discretion to search vehicles incident to arrest, the Belton rule may have led to unjustified civil rights violations and racial profiling. This Article argues that, by limiting vehicle searches incident to arrest, Gant may have disincentivized policing tactics that disproportionately target individuals of color without jeopardizing officer safety. By utilizing a data set of traffic stops from thirteen law enforcement agencies in seven states, this Article presents an empirical study of the effects of shifting doctrines related to vehicle searches incident to arrest. This Article makes two findings. First, it finds no evidence that Gant endangered officer safety. Changes in state doctrines related to vehicle searches incident to arrest are not associated with increases in assaults of officers during traffic stops. Second, it hypothesizes that Gant may have reduced racial profiling. Gant may be linked to a somewhat larger decline in vehicle searches incident to arrest for nonwhite individuals relative to white individuals. These findings are a reminder that seemingly neutral procedural choices by courts in regulating police behavior may have racially disparate effects. We conclude by arguing for the narrowing of the discretionary authority of police officers as a mechanism for reducing disparities in the criminal justice system

Tourist Pathways in Cities: Providing Insights into Tourists Spatial Behaviour

Cities are shaped by flows of people, money and goods. Amongst the people who move through cities are tourists. The types of activities and spaces within cities that satisfy a tourist’s needs are often concentrated into distinctive geographic areas – precincts – and the tourist’s experience is most commonly one of moving between these precincts in search of the city’s highlights. While the movement of tourists through cities is observable, it is complex and not well understood. Understanding tourists’ spatial behaviour can greatly assist those engaged in the management and planning of urban destinations. To address this issue, since 2007 researchers in the Urban Tourism Program at the University of Technology Sydney have been examining tourists’ spatial behaviour using GPS technology, in tandem with other methods that assist with ‘interpreting’ the spatial activity. Studies have been conducted in Sydney, Canberra, London and Melbourne. This paper provides insights into how tourists view and use the city, highlighting differences in their general patterns and range of movement in these cities

An Empirical Analysis of Sexual Orientation Discrimination

This study is the first to empirically demonstrate widespread discrimination across the United States based on perceived sexual orientation, sex, and race in mortgage lending. Our analysis of over five million mortgage applications reveals that any Fair Housing Administration (FHA) loan application filed by same-sex male co-applicants is significantly less likely to be approved compared to the white heterosexual baseline (holding lending risk constant). The most likely explanation for this pattern is sexual orientation–based discrimination—despite the fact that FHA loans are the only type of loan in which discrimination on the basis of sexual orientation is prohibited. Moreover, we find compelling evidence to support the intersectionality theory. According to this theory, when sex and race unite, a new form of discrimination emerges that cannot be explained by sexism or racism alone. The data unequivocally indicates that the race and sex of same-sex applicants play a role and result in a unique and previously unobserved pattern. This discriminatory pattern plagues every region in the United States, and it transcends party lines (that is, it is present in red, blue, and swing states). Furthermore, upending conventional wisdom, the data reveals that big banks discriminate at the same rate as small banks, and lenders in urban environments are as discriminatory as rural lenders. Prior studies failed to reveal this phenomenon due to data constraints and design flaws. These studies relied on testers posing as applicants, and none could investigate how intersectionality influences lending practices. Despite the grim results, a silver lining exists. We find that the pattern of discrimination diminishes or disappears in states and localities that pass anti–sexual orientation discrimination laws. These findings have important and timely implications. In 2017, a new bill offering nationwide protection from sexual orientation credit discrimination was introduced. The same year experienced tectonic changes in Title VII jurisprudence. Our study can reinvigorate the debate and help policymakers tailor remedies that would correct the discriminatory pattern this study unravel

Urban Tourism Research. Developing an Agenda

The study of urban tourism and associated focus on urban tourist precincts is a growing area of interest as practitioners, researchers and policy makers seek to understand the phenomenon of tourism within the urban environment. In Australia research in this area has lacked integration and has not engaged sufficiently with the contextual setting of the urban environment. This paper reports on a study that was undertaken to identify the important areas that should be included in an urban tourism research agenda. This paper has three aims: to review the literature on urban tourism; to outline the process that was undertaken to identify areas for urban tourism research; and to present a conceptual framework that can be used to focus future urban tourism research. © 2008 Elsevier Ltd. All rights reserved

Supreme Optimizer

A Python-based machine learning algorithm was designed for the function of the traffic signal controller. Traffic signal controllers are the decision-making component within a traffic control box. Signal controllers determine when and which traffic lights transition from one phase to the next. The deep Q-learning algorithm designed in this project looked to decrease average vehicle delay, the expected amount of stoppage the average vehicle should expect, by a minimum of 10%. This reduction in vehicle wait times will have a noticeable impact on vehicle emissions created by interrupted vehicle flow, making the signalized intersection system more environmentally friendly. On top of these performance-based metrics, the design provided by this project can be implemented theoretically in easily available and cost-reasonable hardware, allowing transportation authorities to save considerable amounts of taxpayer money on the designed product

F, G, K, M Spectral Standards in the Y Band (0.95-1.11 um)

We take advantage of good atmospheric transparency and the availability of high quality instrumentation in the 1 um near-infrared atmospheric window to present a grid of F, G, K, and M spectral standards observed at high spectral resolution (R ~ 25,000). In addition to a spectral atlas, we present a catalog of atomic line absorption features in the 0.95-1.11 um range. The catalog includes a wide range of line excitation potentials, from 0-13 eV, arising from neutral and singly ionized species, most frequently those of Fe I and Ti I at low excitation, Cr I, Fe I, and Si I at moderate excitation, and C I, S I, and Si I having relatively high excitation. The spectra also include several prominent molecular bands from CN and FeH. For the atomic species, we analyze trends in the excitation potential, line depth, and equivalent width across the grid of spectroscopic standards to identify temperature and surface gravity diagnostics near 1 um. We identify the line ratios that appear especially useful for spectral typing as those involving Ti I and C I or S I, which are temperature sensitive in opposite directions, and Sr II, which is gravity sensitive at all spectral types. Ascii versions of all spectra are available to download with the electronic version of the journal.Comment: 40 pages, 21 figures, 4 tables, spectra available for download with source file, updated to mirror published versio

The Effects of Voluntary and Presumptive Sentencing Guidelines

This Article empirically illustrates that the introduction of voluntary and presumptive sentencing guidelines at the state-level can contribute to statistically significant reductions in sentence length, inter-judge disparities, and racial disparities. For much of American history, judges had largely unguided discretion to select criminal sentences within statutorily authorized ranges. But in the mid-to-late twentieth century, states and the federal government began experimenting with sentencing guidelines designed to reign in judicial discretion to ensure that similarly situated offenders received comparable sentences. Some states have made their guidelines voluntary, while others have made their guidelines presumptive or mandatory, meaning that judges must generally adhere to them unless they can justify a departure. In order to explore the effects of both voluntary and presumptive sentencing guidelines on judicial behavior, this Article relies on a comprehensive dataset of 221,934 criminal sentences handed down by 355 different judges in Alabama between 2002 and 2015. This dataset provides a unique opportunity to address this empirical question, in part because of Alabama’s legislative history. Between 2002 and 2006, Alabama had no sentencing guidelines. In 2006, the state introduced voluntary sentencing guidelines. Then in 2013, the state made these sentencing guidelines presumptive for some non-violent offenses. Using a difference-in-difference framework, we find that the introduction of voluntary sentencing guidelines in Alabama coincided with a decrease in average sentence length of around seven months. When the same guidelines became presumptive, the average sentence length dropped by almost two years. Further, using a triple difference framework, we show that the adoption of these sentencing guidelines coincided with around eight to twelve-month reductions in race-based sentencing disparities and substantial reductions in inter-judge sentencing disparities across all classes of offenders. Combined, this data suggests that voluntary and presumptive sentencing guidelines can help states combat inequality in their criminal justice systems while controlling the sizes of their prison populations