Systematic Test and Evaluation of Metal Detectors: The EC\u27s STEMD Project

There is an international need for people within the humanitarian demining community (HDC) to be informed about appropriate metal detectors for the clearance process. Those involved in information exchange within the HDC will know that metal detector trials are performed regularly. User requirements and test results can easily be published because a network exists within the HDC. The Journal of Mine Action itself is part of this network and readers will probably also be familiar with the websites and publications of the International Test and Evaluation Program for Humanitarian Demining (ITEP) and the Geneva International Centre for Humanitarian Demining (GICHD). The GICHD periodically publishes a metal detector catalogue containing manufacturers\u27 specifications and references to test reports. Since the middle of the 1990s, increased efforts have been made to improve testing and develop reliable and systematic methods. The European Commission\u27s (EC\u27s) project, Systematic Test and Evaluation of Metal Detectors (STEMD), is a new step in this development

The modelling of electromagnetic methods for the nondestructive testing of fatigue cracks

This thesis describes a theoretical and experimental investigation of electromagnetic methods for the detection and measurement of metal fatigue cracks. The available methods are reviewed, with particular attention being paid to mathematical models, and a new model of the electromagnetic field near a metal fatigue crack for small skin-depths is presented which uses a surface impedance boundary condition with the addition of a line source to represent the crack. This leads to a coupled system of two magnetic scalar potentials, one on the crack face which obeys the two-dimensional Laplace equation and one outside the test-piece which obeys the three-dimensional Laplace equation. The behaviour of the field is governed by a parameter m =l/(μ, δ), where l is the size of the field perturbation, μ, is the relative permeability and δ is the skin-depth. When m is small, almost all the flux is concentrated inside the metal and the exterior potential also obeys the two-dimensional Laplace equation, on the test-piece surface. When m is large, the perturbation part of the exterior field has a negligible effect on the field inside the crack so that the crack-face potential may be found by the Born approximation. The general m problem is solved for rectangular and semi-elliptical cracks in flat plates, interrogated by uniform fields, and the solution is verified experimentally. A method for calculating the crack depth from the magnetic field is given, with descriptions of industrial applications. The theory is further developed to find the impedance change in an air-cored circular coil caused by a crack, to find the field near overlapping cracks and to find the field near a crack in an interior corner. Finally, a semi-empirical analysis is presented for a ferrite-cored measuring coil

Where Technology and Field Information Meet: The Metal Detector Handbook

The Metal Detector Handbook for Humanitarian Demining explains what all operators need to know about modern metal detectors. If trying to test, select or simply use a detector to its optimal ability, this handbook will show the user exactly what is needed. The handbook is in pocket A5 format and is resistant to field use

Understanding person acquisition using an interactive activation and competition network

Face perception is one of the most developed visual skills that humans display, and recent work has attempted to examine the mechanisms involved in face perception through noting how neural networks achieve the same performance. The purpose of the present paper is to extend this approach to look not just at human face recognition, but also at human face acquisition. Experiment 1 presents empirical data to describe the acquisition over time of appropriate representations for newly encountered faces. These results are compared with those of Simulation 1, in which a modified IAC network capable of modelling the acquisition process is generated. Experiment 2 and Simulation 2 explore the mechanisms of learning further, and it is demonstrated that the acquisition of a set of associated new facts is easier than the acquisition of individual facts in isolation of one another. This is explained in terms of the advantage gained from additional inputs and mutual reinforcement of developing links within an interactive neural network system. <br/

Logarithmic Operators and Dynamical Extention of The Symmetry Group in the Bosonic SU(2)_0 and SUSY SU(2)_2 WZNW Models

We study the operator product expansion in the bosonic $SU(2)_0$ and SUSY $SU(2)_2$ WZNW models. We find that these OPEs contain both logarithmic operators and new conserved currents, leading to an extension of the symmetry group.Comment: 16 pages, Late

Counting matrices over finite fields with support on skew Young diagrams and complements of Rothe diagrams

We consider the problem of finding the number of matrices over a finite field with a certain rank and with support that avoids a subset of the entries. These matrices are a q-analogue of permutations with restricted positions (i.e., rook placements). For general sets of entries these numbers of matrices are not polynomials in q (Stembridge 98); however, when the set of entries is a Young diagram, the numbers, up to a power of q-1, are polynomials with nonnegative coefficients (Haglund 98). In this paper, we give a number of conditions under which these numbers are polynomials in q, or even polynomials with nonnegative integer coefficients. We extend Haglund's result to complements of skew Young diagrams, and we apply this result to the case when the set of entries is the Rothe diagram of a permutation. In particular, we give a necessary and sufficient condition on the permutation for its Rothe diagram to be the complement of a skew Young diagram up to rearrangement of rows and columns. We end by giving conjectures connecting invertible matrices whose support avoids a Rothe diagram and Poincar\'e polynomials of the strong Bruhat order.Comment: 24 pages, 9 figures, 1 tabl

Telephone follow-up to identify incident lung cancer symptoms in COPD patients

Background: COPD patients are at very high risk of lung cancer, yet new respiratory symptoms of lung cancer may be particularly hard to identify. Aim: We sought to assess the feasibility of actively seeking lung cancer symptoms to improve the timeliness of diagnosis in this group. Design and setting: Observational study to evaluate the feasibility and practicability of the intervention. Patients were recruited from a primary care COPD register and were contacted by telephone 4-monthly over 12 months. Chest X-ray rates were assessed over the 20 months before, during the intervention and for 20 months following it, in both the study group and in patients on the register who did not volunteer for the intervention. Results: Most symptoms were identified at the first call, with 13 (17%) subjects admitting to a new persistent cough and 7 (9%) to a change in their cough. As a result of symptoms identified on the first call, 21 (27%) of the participating patients were referred for a chest X-ray and 4 (5%) were referred urgently to secondary care. Incident symptoms continued frequently to be identified at all subsequent calls, with an overall total of 49% of patients qualifying for and receiving a chest X-ray. Interestingly, the chest X-ray rate remained significantly elevated for the 20 months following the intervention, whilst there appeared to be little change in the non-study COPD patients. Conclusion: The intervention was readily practicable and lung cancer symptoms were frequently identified. The intervention may have resulted in a behavior change leading to a persistently higher chest X-ray rate, although the comparator group was not a formal control group and further assessment in a randomized control trial appears justified

Melatonin for rapid eye movement sleep behavior disorder in Parkinson's disease : a randomised controlled trial

Background Melatonin may reduce REM-sleep behavior disorder (RBD) symptoms in Parkinson's disease (PD), though robust clinical trials are lacking. Objective To assess the efficacy of prolonged-release (PR) melatonin for RBD in PD. Methods Randomized, double-blind, placebo-controlled, parallel-group trial with an 8-week intervention and 4-week observation pre- and postintervention (ACTRN12613000648729). Thirty PD patients with rapid eye movement sleep behavior disorder were randomized to 4 mg of prolonged-release melatonin (Circadin) or matched placebo, ingested orally once-daily before bedtime. Primary outcome was the aggregate of rapid eye movement sleep behavior disorder incidents averaged over weeks 5 to 8 of treatment captured by a weekly diary. Data were included in a mixed-model analysis of variance (n = 15 per group). Results No differences between groups at the primary endpoint (3.4 events/week melatonin vs. 3.6 placebo; difference, 0.2; 95% confidence interval = -3.2 to 3.6; P = 0.92). Adverse events included mild headaches, fatigue, and morning sleepiness (n = 4 melatonin; n = 5 placebo). Conclusion Prolonged-release melatonin 4 mg did not reduce rapid eye movement sleep behavior disorder in PD. (c) 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society

Brain rhythms define distinct interaction networks with differential dependence on anatomy

Cognitive functions are subserved by rhythmic neuronal synchronization across widely distributed brain areas. In 105 area pairs, we investigated functional connectivity (FC) through coherence, power correlation, and Granger causality (GC) in the theta, beta, high-beta, and gamma rhythms. Between rhythms, spatial FC patterns were largely independent. Thus, the rhythms defined distinct interaction networks. Importantly, networks of coherence and GC were not explained by the spatial distributions of the strengths of the rhythms. Those networks, particularly the GC networks, contained clear modules, with typically one dominant rhythm per module. To understand how this distinctiveness and modularity arises on a common anatomical backbone, we correlated, across 91 area pairs, the metrics of functional interaction with those of anatomical projection strength. Anatomy was primarily related to coherence and GC, with the largest effect sizes for GC. The correlation differed markedly between rhythms, being less pronounced for the beta and strongest for the gamma rhythm