Reflective scattering effects in double-pomeron exchange processes

We discuss energy dependence of rapidity gap survival probability in the double-pomeron exchange processes with account of the reflective scattering effects.Comment: 11 pages, 3 figure

Simulation of Three Dimensional Electrostatic Field Configuration in Wire Chambers : A Novel Approach

Three dimensional field configuration has been simulated for a simple wire chamber consisting of one anode wire stretched along the axis of a grounded square cathode tube by solving numerically the boundary integral equation of the first kind. A closed form expression of potential due to charge distributed over flat rectangular surface has been invoked in the solver using Green's function formalism leading to a nearly exact computation of electrostatic field. The solver has been employed to study the effect of several geometrical attributes such as the aspect ratio ($\lambda = \frac{l}{d}$, defined as the ratio of the length $l$ of the tube to its width $d$) and the wire modeling on the field configuration. Detailed calculation has revealed that the field values deviate from the analytic estimates significantly when the $\lambda$ is reduced to 2 or below. The solver has demonstrated the effect of wire modeling on the accuracy of the estimated near-field values in the amplification region. The thin wire results can be reproduced by the polygon model incorporating a modest number of surfaces ($\geq 32$) in the calculation with an accuracy of more than 99%. The smoothness in the three dimensional field calculation in comparison to fluctuations produced by other methods has been observed.Comment: Revised version submitted to Elsevier Science including some more near-field calculation

An Iterative and Toolchain-Based Approach to Automate Scanning and Mapping Computer Networks

As today's organizational computer networks are ever evolving and becoming more and more complex, finding potential vulnerabilities and conducting security audits has become a crucial element in securing these networks. The first step in auditing a network is reconnaissance by mapping it to get a comprehensive overview over its structure. The growing complexity, however, makes this task increasingly effortful, even more as mapping (instead of plain scanning), presently, still involves a lot of manual work. Therefore, the concept proposed in this paper automates the scanning and mapping of unknown and non-cooperative computer networks in order to find security weaknesses or verify access controls. It further helps to conduct audits by allowing comparing documented with actual networks and finding unauthorized network devices, as well as evaluating access control methods by conducting delta scans. It uses a novel approach of augmenting data from iteratively chained existing scanning tools with context, using genuine analytics modules to allow assessing a network's topology instead of just generating a list of scanned devices. It further contains a visualization model that provides a clear, lucid topology map and a special graph for comparative analysis. The goal is to provide maximum insight with a minimum of a priori knowledge.Comment: 7 pages, 6 figure

Measurement of Direct Photon Emission in K^+ -> pi^+ pi^0 gamma Decay

We have performed a measurement of the K^+ -> pi^+ pi^0 gamma decay and have observed 2 X 10^4 events. The best fit to the decay spectrum gives a branching ratio for direct photon emission of (4.7\pm0.8\pm0.3) X 10^{-6} in the pi^+ kinetic energy region of 55 to 90 MeV and requires no component due to interference with inner bremsstrahlung.Comment: 9 pages, 3 figures. To be submitted to PR

Closed Strings with Low Harmonics and Kinks

Low-harmonic formulas for closed relativistic strings are given. General parametrizations are presented for the addition of second- and third-harmonic waves to the fundamental wave. The method of determination of the parametrizations is based upon a product representation found for the finite Fourier series of string motion in which the constraints are automatically satisfied. The construction of strings with kinks is discussed, including examples. A procedure is laid out for the representation of kinks that arise from self-intersection, and subsequent intercommutation, for harmonically parametrized cosmic strings.Comment: 39, CWRUTH-93-

Novel digital biomarkers for frontotemporal dementia

Frontotemporal dementia (FTD) is a heterogenous neurodegenerative disease and is caused by an autosomal dominant mutation in around one third of cases. This pattern of inheritance enables FTD to be studied in the presymptomatic phase, where individuals carry the genetic mutation but have yet to develop symptoms. There are currently no approved treatments for FTD, although clinical trials aiming to target interventions at the earliest disease stage, are underway. There is an urgent need for biomarkers that can reliably detect and monitor the progression of disease in the presymptomatic period, though there are a distinct lack of sensitive cognitive measures. This thesis aims to establish the validity and sensitivity of a set of digital biomarkers that can be used to measure cognitive function in FTD. I begin this thesis by describing the Ignite computerised cognitive assessment, developing normative properties for the tests through a remote data collection study in over 2,000 healthy controls. I build upon this validation by establishing the concurrent validity of Ignite with gold-standard pen and paper tasks, the test-retest reliability upon repeated administration, and demonstrate the tests are sensitive to presymptomatic impairment across several cognitive domains. I also describe a novel portable eye tracking experiment that can be completed outside of the lab, first highlighting the validity of the tests as measures of cognitive function and demonstrating their sensitivity in detecting early changes in social cognition in the presymptomatic period. Finally, I investigate a smartphone app that passively monitors human-device interactions to generate digital biomarkers of cognitive function. I establish the acceptability of the app in the general population before demonstrating the measures produced can detect differences in keyboard interactions in presymptomatic FTD mutation carriers. This work provides evidence that biomarkers generated from different digital devices are valid and sensitive measures of cognitive impairment in FTD. Therefore, digital biomarkers could replace outdated pen and paper tasks and be used as outcome measures in clinical trials

The Lore of Low Methane Livestock:Co-Producing Technology and Animals for Reduced Climate Change Impact

Methane emissions from sheep and cattle production have gained increasing profile in the context of climate change. Policy and scientific research communities have suggested a number of technological approaches to mitigate these emissions. This paper uses the concept of co-production as an analytical framework to understand farmers’ evaluation of a 'good animal’. It examines how technology and sheep and beef cattle are co-produced in the context of concerns about the climate change impact of methane. Drawing on 42 semi-structured interviews, this paper demonstrates that methane emissions are viewed as a natural and integral part of sheep and beef cattle by farmers, rather than as a pollutant. Sheep and beef cattle farmers in the UK are found to be an extremely heterogeneous group that need to be understood in their specific social, environmental and consumer contexts. Some are more amenable to appropriating methane reducing measures than others, but largely because animals are already co-constructed from the natural and the technical for reasons of increased production efficiency