Miniature spectrally selective dosimeter

A miniature spectrally selective dosimeter capable of measuring selected bandwidths of radiation exposure on small mobile areas is described. This is achieved by the combination of photovoltaic detectors, electrochemical integrators (E-cells) and filters in a small compact case which can be easily attached in close proximity to and substantially parallel to the surface being measured. In one embodiment two photovoltaic detectors, two E-cells, and three filters are packaged in a small case with attaching means consisting of a safety pin. In another embodiment, two detectors, one E-cell, three filters are packaged in a small case with attaching means consisting of a clip to clip over a side piece of an eye glass frame

Hill's Equation with Random Forcing Parameters: Determination of Growth Rates through Random Matrices

This paper derives expressions for the growth rates for the random 2 x 2 matrices that result from solutions to the random Hill's equation. The parameters that appear in Hill's equation include the forcing strength and oscillation frequency. The development of the solutions to this periodic differential equation can be described by a discrete map, where the matrix elements are given by the principal solutions for each cycle. Variations in the forcing strength and oscillation frequency lead to matrix elements that vary from cycle to cycle. This paper presents an analysis of the growth rates including cases where all of the cycles are highly unstable, where some cycles are near the stability border, and where the map would be stable in the absence of fluctuations. For all of these regimes, we provide expressions for the growth rates of the matrices that describe the solutions.Comment: 22 pages, 3 figure

The Downfall of Incumbent Protection : Case Study and Implications

On January 9, 2019, the United States Court of Appeals for the Fourth Circuit struck down Virginia Code section 24.2-509— Virginia’s long-standing “Incumbent Protection Act” (or the “Act”). The Incumbent Protection Act was the only statute of its kind, and had endured criticism by grassroots commentators. Yet, the Incumbent Protection Act had long evaded scrutiny in the courtroom. Indeed, the Incumbent Protection Act’s courtroom history is labyrinthine, replete with interesting and significant commentaries on party rights, standing, and public policy preference for primaries. In fact, before its eventual demise, it had been implicated in several lawsuits bringing constitutional challenges to various Virginia election laws and had dodged one direct assault by defending on standing grounds. By the time the challenge to the Incumbent Protection Act culminated with the Fourth Circuit’s January 9, 2019 decision, litigation to dismantle it had been ongoing for almost five years between two different suits. Indeed, the Incumbent Protection Act was felled not by one, but two swings. This Article chronicles the course of the litigation that ultimately toppled the Incumbent Protection Act. Spanning two lawsuits and no fewer than seven opinions, the story of the litigation provides insight to practitioners who hope to navigate the interlocking and overlapping hierarchies of party plans, state laws, and constitutional rights. Following the summary and analysis of the litigation, this Article will assess the ramifications of the two Fourth Circuit opinions and will look ahead to issues likely of interest to future challengers to Virginia’s election laws

The harmonic measure of diffusion-limited aggregates including rare events

We obtain the harmonic measure of diffusion-limited aggregate (DLA) clusters using a biased random-walk sampling technique which allows us to measure probabilities of random walkers hitting sections of clusters with unprecedented accuracy; our results include probabilities as small as 10- 80. We find the multifractal D(q) spectrum including regions of small and negative q. Our algorithm allows us to obtain the harmonic measure for clusters more than an order of magnitude larger than those achieved using the method of iterative conformal maps, which is the previous best method. We find a phase transition in the singularity spectrum f(α) at α≈14 and also find a minimum q of D(q), qmin=0.9±0.05

The Behavioural Outcomes of Anxiety scale (BOA): A preliminary validation in stroke survivors

© 2014 The British Psychological Society. Objectives To determine the psychometric properties of an observational scale of anxiety.Design A cross-sectional and longitudinal survey with stroke survivor-carer dyads.Methods Eighty-nine dyads recruited in community stroke groups completed: a demographic questionnaire; the Behavioural Outcomes of Anxiety scale (BOA), survivor-rated (survivor BOA) and carer-rated (carer BOA) versions; the anxiety scale of the Hospital Anxiety and Depression Scales (HADS-A), also in carer and survivor versions. Twenty-seven survivors and carers repeated the BOA after 1 week.Results Correlations between the carer BOA and the survivor HADS-A (r =.55, p <.001) and the survivor BOA (r =.73, p <.001) demonstrated construct validity. Cronbach's alpha for the carer BOA was.81; item statistics did not identify any items for exclusion. The test-retest coefficient at 1 week was 0.83. Receiver operating characteristic analysis against the survivor HADS-A and BOA produced areas under the curve of 0.75 and 0.88, respectively. At a cut-off score of 13/14 sensitivity and specificity against the HADS-A were 0.77 and 0.58, respectively, and 0.86 and 0.68 against the survivor BOA. The impact of stroke on memory was associated with elevated anxiety. Scores for both BOA versions were independent of demographic variables.Conclusions The carer BOA has acceptable psychometric properties and is independent of survivor demographic variables such as age. It identifies self-reported cases with acceptable sensitivity and specificity. It has potential for use with persons unable to self-report anxiety. Further validation is recommended, but its continuing use is supported. © 2014 The British Psychological Society

Topologies of nodal sets of random band limited functions

It is shown that the topologies and nestings of the zero and nodal sets of random (Gaussian) band limited functions have universal laws of distribution. Qualitative features of the supports of these distributions are determined. In particular the results apply to random monochromatic waves and to random real algebraic hyper-surfaces in projective space.Comment: 62 pages. Major revision following referee repor

Active controls: A look at analytical methods and associated tools

A review of analytical methods and associated tools for active controls analysis and design problems is presented. Approaches employed to develop mathematical models suitable for control system analysis and/or design are discussed. Significant efforts have been expended to develop tools to generate the models from the standpoint of control system designers' needs and develop the tools necessary to analyze and design active control systems. Representative examples of these tools are discussed. Examples where results from the methods and tools have been compared with experimental data are also presented. Finally, a perspective on future trends in analysis and design methods is presented

Magnetic hydrodynamics with asymmetric stress tensor

In this paper we study equations of magnetic hydrodynamics with a stress tensor. We interpret this system as the generalized Euler equation associated with an abelian extension of the Lie algebra of vector fields with a non-trivial 2-cocycle. We use the Lie algebra approach to prove the energy conservation law and the conservation of cross-helicity

Dephasing of Electrons on Helium by Collisions with Gas Atoms

The damping of quantum effects in the transport properties of electrons deposited on a surface of liquid helium is studied. It is found that due to vertical motion of the helium vapour atoms the interference of paths of duration $t$ is damped by a factor $\exp - (t/\tau_v)^3$. An expression is derived for the weak-localization lineshape in the case that damping occurs by a combination of processes with this type of cubic exponential damping and processes with a simple exponential damping factor.Comment: 7 pages, 2 figures, Revte