Internal symmetries and bootstrap models

Chapter 1 serves ms a brief introduction to the ideas which form the subject of this thesis, internal symmetry, bootstraps, duality and the quark model. In Chapters 2 and 3 we survey predictions for internal symmetries made from (^N)/D bootstraps and the duality hypothesis respectively. Both approaches predict a Lie group structure and predict the meson representations. In addition the duality equations imply that the baryons transform as two-quark composites. A phenomenological choice of a subset of the duality constraints can be made which has a physical three-quark solution. Symmetry breaking is discussed in both cases. In Chapter 4 we contrast the predictions surveyed in the previous two chapters. Duality requires exchange degeneracies among trajectories of different multiplet8 but these do not result from (^N)/D models. In the dual case the even-signature, isosinglet trajectories are identified with mixed f, f' states, degenerate with the W,Ѳ respectively, whereas bootstrap models always produce a high-lying singlet trajectory which is most naturally identified with the Pomeron. It is argued that these differences make it unlikely that dual models can be deduced in any simple way from the bootstrap hypothesis. An (^N)/D quark model with meson exchanges is examined in Chapter 5. With the assumption that the quark mass is much larger than the meson mass, a singlet meson trajectory is obtained which lies an order of magnitude above the octet trajectories. This result is unaltered if symmetry breaking of any order is allowed. These difficulties are not removed by treating the particle exchange forces as perturbations to a background term. It is concluded that these results together with the known difficulties of obtaining physical slopes and intercepts imply that this type of quark model should probably be discarded

Examining the geographies of human trafficking: Methodological challenges in mapping trafficking's complexities and connectivities

There is relatively little empirical research into the geographies of human trafficking, despite its inherent spatiality and the clear benefits of geographical perspectives. An emerging but vibrant body of qualitative work explores different aspects of trafficking's spatiality and spatio-temporality in depth and nuance, but equivalent quantitative analyses are notably lacking. What exists is largely limited to crude maps and broad-brushed assessments of patterns and trends. Yet, rigorous quantitative work is also vital in advancing understanding, informing responses and increasing accountability. In this paper, we present a novel, empirically-substantiated examination of methodological challenges in mapping trafficking. We draw on analysis of data extracted from the case files of 450 formally identified labour trafficking victims (accessed via the UK's National Crime Agency). We identify and illustrate five characteristics of the data creating particular challenges for geospatial analysis: data integrity (regarding completeness, accuracy and consistency); geographical uncertainty (regarding spatial accuracy and specificity); managing multiple geographies (trafficking is a complex process with various stages, each potentially involving numerous locations); diversity and disaggregation (important geographical variations can be masked in aggregated analysis); and unclear journeys (analysing trafficking routes proved particularly complicated). We also consider possible solutions and explore implications for future research, policy and practice

The effect of GPS refresh rate on measuring police patrol in micro-places

© 2021, The Author(s). With the increasing prevalence of police interventions implemented in micro hot-spots of crime, the accuracy with which officer foot patrols can be measured is increasingly important for the robust evaluation of such strategies. However, it is currently unknown how the accuracy of GPS traces impact upon our understanding of where officers are at a given time and how this varies for different GPS refresh rates. Most existing studies that use GPS data fail to acknowledge this. This study uses GPS data from police officer radios and ground truth data to estimate how accurate GPS data are for different GPS refresh rates. The similarity of the assumed paths are quantitatively evaluated and the analysis shows that different refresh rates lead to diverging estimations of where officers have patrolled. These results have significant implications for the measurement of police patrols in micro-places and evaluations of micro-place based interventions

Data and evidence challenges facing place-based policing

PURPOSE: The purpose of this paper is to use an evaluation of a micro-place-based hot-spot policing implementation to highlight the potential issues raised by data quality standards in the recording and measurement of crime data and police officer movements. DESIGN/METHODOLOGY/APPROACH: The study focusses on an area of London (UK) which used a predictive algorithm to designate micro-place patrol zones for each police shift over a two-month period. Police officer movements are measured using GPS data from officer-worn radios. Descriptive statistics regarding the crime data commonly used to evaluate this type of implementation are presented, and simple analyses are presented to examine the effects of officer patrol duration (dosage) on crime in micro-place hot-spots. FINDINGS: The results suggest that patrols of 10-20 minutes in a given police shift have a significant impact on reducing crime; however, patrols of less than about 10 minutes and more than about 20 minutes are ineffective at deterring crime. RESEARCH LIMITATIONS/IMPLICATIONS: Due to the sparseness of officer GPS data, their paths have to be interpolated which could introduce error to the estimated patrol dosages. Similarly, errors and uncertainty in recorded crime data could have substantial impact on the designation of micro-place interventions and evaluations of their effectiveness. ORIGINALITY/VALUE: This study is one of the first to use officer GPS data to estimate patrol dosage and places particular emphasis on the issue of data quality when evaluating micro-place interventions

A Tonal Analysis of Gurung, with Separate Systems for Register and Contour Pitch Features

An earlier analysis of Gurung, by Burton-Page in BSOAS, 17/1, 1955, put forward a single system, of two terms, for the word unit in the dialect spoken in Ghandrung: tones 1 and 2; the present analysis of the Gurung of a speaker from the centre of the Gurung area differs from Burton-Page's in that it distinguishes two tone systems: a two-term system (tones 1 and 2) for a difference in pitch register and a further two-term system (tones A and B) for a difference in pitch contour. Support for separating register-pitch and contour-pitch differences comes from three associated features, aspiration, phonation and voice: they apply to the register distinction but not to the contour distinction. Further support comes from comparing this tonal analysis with an identical analysis of a closely related language, Tamang, and also with the two-term system put forward for the word in Tibetan

Detection of fixed points in spatiotemporal signals by clustering method

We present a method to determine fixed points in spatiotemporal signals. A 144-dimensioanl simulated signal, similar to a Kueppers-Lortz instability, is analyzed and its fixed points are reconstructed.Comment: 3 pages, 3 figure

Do Employees From Less-Healthy Communities Use More Care and Cost More? Seeking to Establish a Business Case for Investment in Community Health.

INTRODUCTION: Few studies have examined the impact of community health on employers. We explored whether employed adults and their adult dependents living in less-healthy communities in the greater Philadelphia region used more care and incurred higher costs to employers than employees from healthier communities. METHODS: We used a multi-employer database to identify adult employees and dependents with continuous employment and mapped them to 31 zip code regions. We calculated community health scores at the regional level, by using metrics similar to the Robert Wood Johnson Foundation (RWJF) County Health Rankings but with local data. We used descriptive analyses and multilevel linear modeling to explore relationships between community health and 3 outcome variables: emergency department (ED) use, hospital use, and paid claims. Business leaders reviewed findings and offered insights on preparedness to invest in community health improvement. RESULTS: Poorer community health was associated with high use of ED services, after controlling for age and sex. After including a summary measure of racial composition at the zip code region level, the relationship between community health and ED use became nonsignificant. No significant relationships between community health and hospitalizations or paid claims were identified. Business leaders expressed interest in further understanding health needs of communities where their employees live. CONCLUSION: The health of communities in which adult employees and dependents live was associated with ED use, but similar relationships were not seen for hospitalizations or paid claims. This finding suggests a need for more primary care access. Despite limited quantitative evidence, business leaders expressed interest in guidance on investing in community health improvement

Stimulus statistics shape oscillations in nonlinear recurrent neural networks.

Rhythmic activity plays a central role in neural computations and brain functions ranging from homeostasis to attention, as well as in neurological and neuropsychiatric disorders. Despite this pervasiveness, little is known about the mechanisms whereby the frequency and power of oscillatory activity are modulated, and how they reflect the inputs received by neurons. Numerous studies have reported input-dependent fluctuations in peak frequency and power (as well as couplings across these features). However, it remains unresolved what mediates these spectral shifts among neural populations. Extending previous findings regarding stochastic nonlinear systems and experimental observations, we provide analytical insights regarding oscillatory responses of neural populations to stimulation from either endogenous or exogenous origins. Using a deceptively simple yet sparse and randomly connected network of neurons, we show how spiking inputs can reliably modulate the peak frequency and power expressed by synchronous neural populations without any changes in circuitry. Our results reveal that a generic, non-nonlinear and input-induced mechanism can robustly mediate these spectral fluctuations, and thus provide a framework in which inputs to the neurons bidirectionally regulate both the frequency and power expressed by synchronous populations. Theoretical and computational analysis of the ensuing spectral fluctuations was found to reflect the underlying dynamics of the input stimuli driving the neurons. Our results provide insights regarding a generic mechanism supporting spectral transitions observed across cortical networks and spanning multiple frequency bands