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

Museum robots: multi-robot systems for public exhibition

Mobile robots provide a versatile platform for research, however they can also provide an interesting educational platform for public exhibition at museums. In general museums require exhibits that are both eye catching and exciting to the public whilst requiring a minimum of maintenance time from museum technicians. In many cases it is simply not possible to continuously change batteries and some method of supplying continous power is required. A powered flooring system is described that is capable of providing power continuously to a group of robots. Three different museum exhibit applications are described. All three robot exhibits are of a similar basic design although the exhibits are very different in appearance and behaviour. The durability and versatility of the robots also makes them extremely good candidates for long duration experiments such as those required by evolutionary robotics

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

The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin disrupts morphogenesis of the rat pre-implantation embryo

© 2008 Hutt et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The definitive version was published in BMC Developmental Biology 8 (2008): 1, doi:10.1186/1471-213X-8-1.Environmental toxicants, whose actions are often mediated through the aryl hydrocarbon receptor (AhR) pathway, pose risks to the health and well-being of exposed species, including humans. Of particular concern are exposures during the earliest stages of development that while failing to abrogate embryogenesis, may have long term effects on newborns or adults. The purpose of this study was to evaluate the effect of maternal exposure to the AhR-specific ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the development of rat pre-implantation embryos with respect to nuclear and cytoskeletal architecture and cell lineage allocation. We performed a systematic 3 dimensional (3D) confocal microscopy analysis of rat pre-implantation embryos following maternal exposure to environmentally relevant doses of TCDD. Both chronic (50 ng/kg/wk for 3 months) and acute (50 ng/kg and 1 μg/kg at proestrus) maternal TCDD exposure disrupted morphogenesis at the compaction stage (8–16 cell), with defects including monopolar spindle formation, f-actin capping and fragmentation due to aberrant cytokinesis. Additionally, the size, shape and position of nuclei were modified in compaction stage pre-implantation embryos collected from treated animals. Notably, maternal TCDD exposure did not compromise survival to blastocyst, which with the exception of nuclear shape, were morphologically similar to control blastocysts. We have identified the compaction stage of pre-implantation embryogenesis as critically sensitive to the effects of TCDD, while survival to the blastocyst stage is not compromised. To the best of our knowledge this is the first in vivo study to demonstrate a critical window of pre-implantation mammalian development that is vulnerable to disruption by an AhR ligand at environmentally relevant doses.This research was supported by NIH/NIEHS-012916 (BKP), ESHE Fund (DFA), Hall Family Foundation (DFA and KJH) and Biomedical Research Training Grant KUMC (KJH)

With A Love Like Mine

https://digitalcommons.library.umaine.edu/mmb-vp/2768/thumbnail.jp

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

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

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

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