Power spectrum and intermittency of the transmitted flux of QSOs Ly-alpha absorption spectra

Using a set of 28 high resolution, high signal to noise ratio (S/N) QSO Ly-alpha absorption spectra, we investigate the non-Gaussian features of the transmitted flux fluctuations, and their effect upon the power spectrum of this field. We find that the spatial distribution of the local power of the transmitted flux on scales k >= 0.05 s/km is highly spiky or intermittent. The probability distribution functions (PDFs) of the local power are long-tailed. The power on small scales is dominated by small probability events, and consequently, the uncertainty in the power spectrum of the transmitted flux field is generally large. This uncertainty arises due to the slow convergence of an intermittent field to a Gaussian limit required by the central limit theorem (CLT). To reduce this uncertainty, it is common to estimate the error of the power spectrum by selecting subsamples with an "optimal" size. We show that this conventional method actually does not calculate the variance of the original intermittent field but of a Gaussian field. Based on the analysis of intermittency, we propose an algorithm to calculate the error. It is based on a bootstrap re-sampling among all independent local power modes. This estimation doesn't require any extra parameter like the size of the subsamples, and is sensitive to the intermittency of the fields. This method effectively reduces the uncertainty in the power spectrum when the number of independent modes matches the condition of the CLT convergence.Comment: 26 pages (incl. figures). Accepted for publication in MNRA

Media Coverage of Law Enforcement Use of Force and Disability

Disability intersects with other factors such as race, class, gender, and sexuality, to magnify degrees of marginalization and increase the risk of violence. When the media ignores or mishandles a major factor, as we contend they generally do with disability, it becomes harder to effect change.This white paper focuses on the three years of media coverage of police violence and disability since the death of a young man with Down syndrome, named Ethan Saylor, in January 2013. After reviewing media coverage of eight selected cases of police violence against individuals with disabilities, the paper reveals the following patterns in the overall data:? Disability goes unmentioned or is listed as an attribute without context.? An impairment is used to evoke pity or sympathy for the victim.? A medical condition or "mental illness" is used to blame victims for their deaths.? In rare instances, we have identified thoughtful examinations of disability from within its social context that reveal the intersecting forces that lead to dangerous use-of-force incidents. Such stories point the way to better models for policing in the future. We conclude by proposing best practices for reporting on disability and police violence

Virtual Prototyping for Dynamically Reconfigurable Architectures using Dynamic Generic Mapping

This paper presents a virtual prototyping methodology for Dynamically Reconfigurable (DR) FPGAs. The methodology is based around a library of VHDL image processing components and allows the rapid prototyping and algorithmic development of low-level image processing systems. For the effective modelling of dynamically reconfigurable designs a new technique named, Dynamic Generic Mapping is introduced. This method allows efficient representation of dynamic reconfiguration without needing any additional components to model the reconfiguration process. This gives the designer more flexibility in modelling dynamic configurations than other methodologies. Models created using this technique can then be simulated and targeted to a specific technology using the same code. This technique is demonstrated through the realisation of modules for a motion tracking system targeted to a DR environment, RIFLE-62

Double Bottom Line Progress Report: Assessing Social Impact in Double Bottom Line Ventures, Methods Catalog

Outlines methods for social entrepreneurs and their investors to define, measure and communicate social impact and return in early-stage ventures

Double Bottom Line Project Report: Assessing Social Impact in Double Bottom Line Ventures

This tool expresses costs and social impacts of an investment in monetary terms. Quantification is achieved according to one or more of three measures: NPV (the aggregate value of all costs, revenues and social impacts discounted), benefit-cost ratio (the discounted value of revenues and positive impacts divided by discounted value of costs and negative impacts) and internal rate of return (the net value of revenues plus impacts expressed as an annual percentage return on the total costs of the investment)