A Bayesian method for pulsar template generation

Extracting Times of Arrival from pulsar radio signals depends on the knowledge of the pulsars pulse profile and how this template is generated. We examine pulsar template generation with Bayesian methods. We will contrast the classical generation mechanism of averaging intensity profiles with a new approach based on Bayesian inference. We introduce the Bayesian measurement model imposed and derive the algorithm to reconstruct a "statistical template" out of noisy data. The properties of these "statistical templates" are analysed with simulated and real measurement data from PSR B1133+16. We explain how to put this new form of template to use in analysing secondary parameters of interest and give various examples: We implement a nonlinear filter for determining ToAs of pulsars. Applying this method to data from PSR J1713+0747 we derive ToAs self consistently, meaning all epochs were timed and we used the same epochs for template generation. While the average template contains fluctuations and noise as unavoidable artifacts, we find that the "statistical template" derived by Bayesian inference quantifies fluctuations and remaining uncertainty. This is why the algorithm suggested turns out to reconstruct templates of statistical significance from ten to fifty single pulses. A moving data window of fifty pulses, taking out one single pulse at the beginning and adding one at the end of the window unravels the characteristics of the methods to be compared. It shows that the change induced in the classical reconstruction is dominated by random fluctuations for the average template, while statistically significant changes drive the dynamics of the proposed method's reconstruction. The analysis of phase shifts with simulated data reveals that the proposed nonlinear algorithm is able to reconstruct correct phase information along with an acceptable estimation of the remaining uncertainty.Comment: 21 pages, 16 figures, submitted to MNRA

Investigation into the impact of integral suppressor configurations on the pressure levels within the suppressor

This paper reports on an experimental investigation supported by basic modeling in to the performance of an integral suppressor on a low power firearm. A model was developed to determine the pressure within a suppressor chamber using iterative empirical calculations of the gas properties and flow within the system. The design of a reconfigurable suppressor chamber has been undertaken allowing suppressor chamber volume to be varied through the use of baffles. Pressure transducers were used to determine the pressure within the suppressor chamber for a series of firings. The results of the firings with different configurations within the suppressor are presented allowing trends to be established. The modeling and experimental results show an increase in suppressor chamber volume results in a reduction of recorded pressure within the suppressor chamber

City flight migration patterns in the East Midlands

This paper investigates migration to and from the Three Cities of Derby, Leicester and Nottingham. It investigates whether these cities lose more migrants than they gain from more rural parts of the city-regions and the extent to which these flows impact on the demographic profiles of the Three Cities

Urban CDEPs as Indigenous Employment Centres: Policy and community implications

This paper explores the federal government's continued development of its Indigenous Employment Policy (IEP) with the launch of additional Indigenous-specific welfare reform initiatives flagged in the May 2001 Budget. One of these new initiatives focuses in particular on 'urban' Community Development Employment Projects (CDEP) schemes and policy initiatives aimed at encouraging them to take on the additional role of Indigenous Employment Centres (IECs). The key function of IECs will be to move CDEP participants into mainstream employment. The paper presents a description of the policy background to this recent government initiative, and describes the proposed function and objectives of IECs. The then Department of Employment, Workplace Relations and Small Business (DEWRSB) initiated a CDEP Work Preparation and Employment Trial, to test out the new initiative. The possible effects of the IEC initiative on CDEP organisations is examined through a preliminary study of Redfern CDEP in Sydney, which has agreed to participate in an IEC trial. Because the trial had only recently been implemented at the time the field visit was conducted by the author in 2001, the paper is not a comprehensive evaluation of the Redfern trial. Rather, the Redfern case study provides an important preliminary ground-testing of the proposed objectives and implementation of IECs. In conclusion the paper raises some preliminary practical and policy implications for the CDEP scheme in general, and for specific CDEP organisations that may be considering undertaking an IEC role

Opportunities for weed manipulation using GMHT row crops

The herbicides and cultivation systems available in most non-GM crops allow farmers little flexibility as to when they control weeds. However, glyphosate and glufosinate-ammonium, as used in GM herbicide tolerant crops, offer the opportunity to control large weeds and weed control can be timed according to the agronomic and environmental aims of the user. This paper will use sugar beet as a model crop and report results where different approaches to weed control have been used and discuss their relevance in the wider agricultural and environmental contextNon peer reviewe

Wounding patterns and human performance in knife attacks: optimising the protection provided by knife-resistant body armour

Stab attacks generate high loads,1 and to defeat them, armour needs to be of a certain thickness and stiffness.2,3 Slash attacks produce much lower loads and armour designed to defeat them can be far lighter and more flexible.Methods and subjects: Phase 1: Human performance in slash attacks: 87 randomly selected students at the Royal Military College of Science were asked to make one slash attack with an instrumented blade on a vertically mounted target. No instructions on how to slash the target were given. The direction, contact forces and velocity of each attack were recorded. Phase 2: Clinical experience with edged weapon attacks: The location and severity of all penetrating injuries in patients attending the Glasgow Royal Infirmary between 1993 and 1996 were charted on anatomical figures.Results Phase 1: Two types of human slash behaviour were evident: a ‘chop and drag’ blow and a ‘sweep motion’ type of attack. ‘Chop and drag’ attacks had higher peak forces and velocities than sweep attacks. Shoulder to waist blows (diagonal) accounted for 82% of attacks, 71% of attackers used a long diagonal slash with an average cut length of 34 cm and 11% used short diagonal attacks with an average cut length of 25 cm. Only 18% of attackers slashed across the body (short horizontal); the average measured cut length of this type was 28 cm. The maximum peak force for the total sample population was 212 N; the maximum velocity was 14.88 m s−1. The 95 percentile force for the total sample population was 181 N and the velocity was 9.89 m s−1. Phase 2: 431 of the 500 patients had been wounded with edged weapons. The average number of wounds sustained by victims in knife assaults was 2.4. The distribution of wounds by frequency and severity are presented.Conclusions Anti-slash protection is required for the arms, neck, shoulders, and thighs. The clinical experience of knife-attack victims provides information on the relative vulnerabilities of different regions of the body. It is anticipated that designing a tunic-type of Police uniform that is inherently stab and slash resistant will eventually replace the current obvious and often bulky extra protective vest. Attempts at making a combined garment will need to be guided by ergonomic considerations and field testing. A similar anatomical regional risk model might also be appropriate in the design of anti-ballistic armour and combined anti-ballistic and knife-resistant armour

Comparison of porcine thorax to gelatine blocks for wound

Published online first in International Journal of Legal Medicine. The support of EPSRC and The Home Office are recognised. Open Access, this article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http:/ /creativecommons.org/licenses/by/4.0/)Tissue simulants are typically used in ballistic testing as substitutes for biological tissues. Many simulants have been used, with gelatine amongst the most common. While two concentrations of gelatine (10 and 20 %) have been used extensively, no agreed standard exists for the preparation of either. Comparison of ballistic damage produced in both concentrations is lacking. The damage produced in gelatine is also questioned, with regards to what it would mean for specific areas of living tissue. The aim of the work discussed in this paper was to consider how damage caused by selected pistol and rifle ammunition varied in different simulants. Damage to gelatine blocks 10 and 20 % in concentration were tested with 9 mm Luger (9 × 19 full metal jacket; FMJ) rounds, while damage produced by .223 Remington (5.56 × 45 Federal Premium® Tactical® Bonded®) rounds to porcine thorax sections (skin, underlying tissue, ribs, lungs, ribs, underlying tissue, skin; backed by a block of 10 % gelatine) were compared to 10 and 20 % gelatine blocks. Results from the .223 Remington rifle round, which is one that typically expands on impact, revealed depths of penetration in the thorax arrangement were significantly different to 20 % gelatine, but not 10 % gelatine. The level of damage produced in the simulated thoraxes was smaller in scale to that witnessed in both gelatine concentrations,though greater debris was produced in the thoraxes.The support of EPSRC and The Home Office are recognised