Maxwell equations in matrix form, squaring procedure, separating the variables, and structure of electromagnetic solutions

The Riemann -- Silberstein -- Majorana -- Oppenheimer approach to the Maxwell electrodynamics in vacuum is investigated within the matrix formalism. The matrix form of electrodynamics includes three real 4 \times 4 matrices. Within the squaring procedure we construct four formal solutions of the Maxwell equations on the base of scalar Klein -- Fock -- Gordon solutions. The problem of separating physical electromagnetic waves in the linear space \lambda_{0}\Psi^{0}+\lambda_{1}\Psi^{1}+\lambda_{2}\Psi^{2}+ lambda_{3}\Psi^{3} is investigated, several particular cases, plane waves and cylindrical waves, are considered in detail.Comment: 26 pages 16 International Seminar NCPC, May 19-22, 2009, Minsk, Belaru

Quantum tops as examples of commuting differential operators

We study the quantum analogs of tops on Lie algebras $so(4)$ and $e(3)$ represented by differential operators.Comment: 24 p

A zeta function approach to the relation between the numbers of symmetry planes and axes of a polytope

A derivation of the Ces\`aro-Fedorov relation from the Selberg trace formula on an orbifolded 2-sphere is elaborated and extended to higher dimensions using the known heat-kernel coefficients for manifolds with piecewise-linear boundaries. Several results are obtained that relate the coefficients, $b_i$, in the Shephard-Todd polynomial to the geometry of the fundamental domain. For the 3-sphere we show that $b_4$ is given by the ratio of the volume of the fundamental tetrahedron to its Schl\"afli reciprocal.Comment: Plain TeX, 26 pages (eqn. (86) corrected

Hunting for the Dark Matter Wake Induced by the Large Magellanic Cloud

Satellite galaxies are predicted to generate gravitational density wakes as they orbit within the dark matter (DM) halos of their hosts, causing their orbits to decay over time. The recent infall of the Milky Way's (MW) most massive satellite galaxy, the Large Magellanic Cloud (LMC), affords us the unique opportunity to study this process in action. In this work, we present high-resolution ($m_{dm} = 4 \times 10^4 M_{\odot}$ ) N-body simulations of the MW-LMC interaction over the past 2 Gyr. We quantify the impact of the LMC's passage on the density and kinematics of the MW's DM halo and the observability of these structures in the MW's stellar halo. The LMC is found to generate pronounced Local and Global wakes in both the DM and stellar halos, leads to both local overdensities and distinct kinematic patterns that should be observable with ongoing and future surveys. Specifically, the Global Wake will result in redshifted radial velocities of stars in the North and blueshifts in the South, at distances larger than 45 kpc. The Local Wake traces the orbital path of the LMC through the halo (50-200 kpc), resulting in a stellar overdensity with a distinct, tangential kinematic pattern that persists to the present day. The detection of the MW's halo response will constrain: the infall mass of the LMC and its orbital trajectory, the mass of the MW, and it may inform us about the nature of the dark matter particle itself.Comment: 41 pages, 27 figures. Accepted to ApJ. Some terminology was changed. High-resolution images and figures can be found at https://bit.ly/2S25Yz

Transfer-Expanded Graphs for On-Demand Multimodal Transit Systems

This paper considers a generalization of the network design problem for On-Demand Multimodal Transit Systems (ODMTS). An ODMTS consists of a selection of hubs served by high frequency buses, and passengers are connected to the hubs by on-demand shuttles which serve the first and last miles. This paper generalizes prior work by including three additional elements that are critical in practice. First, different frequencies are allowed throughout the network. Second, additional modes of transit (e.g., rail) are included. Third, a limit on the number of transfers per passenger is introduced. Adding a constraint to limit the number of transfers has a significant negative impact on existing Benders decomposition approaches as it introduces non-convexity in the subproblem. Instead, this paper enforces the limit through transfer-expanded graphs, i.e., layered graphs in which each layer corresponds to a certain number of transfers. A real-world case study is presented for which the generalized ODMTS design problem is solved for the city of Atlanta. The results demonstrate that exploiting the problem structure through transfer-expanded graphs results in significant computational improvements.Comment: 9 pages, 4 figure

Effects of sildenafil on maximum walking time in patients with arterial claudication: The ARTERIOFIL study

BACKGROUND: Patients with lower extremity peripheral artery disease (PAD) frequently experience claudication, a clinical symptom indicative of reduced walking capacity. Recommended care consists of exercise rehabilitation combined with optimal medical treatment and surgery. The effects of a single oral dose of sildenafil, a phosphodiesterase type-5 inhibitor, on patients with claudication are discussed. The aim of this study was to test the efficacy of a single 100 mg dose of sildenafil compared to placebo in terms of maximal walking time (MWT) in patients with claudication. METHODS: The ARTERIOFIL study is a crossover, double-blind, prospective, randomized, single-center study conducted at Angers University Hospital in France. MWT (primary endpoint) was assessed using a treadmill test (10% incline; 3.2 km/h). Secondary endpoints (pain-free walking time (PFWT), transcutaneous oximetry during exercise and redox cycle parameters and safety) were also studied. RESULTS: Fourteen patients were included of whom two were ultimately excluded. In the 12 remaining patients, the MWT was significantly improved during the sildenafil period compared with the placebo period (300 s [95% CI 172 s-428 s] vs 402 s [95% CI 274 s-529 s] p < 0.01). Sildenafil had no significant effect on pain-free walking time or skin tissue oxygenation during exercise. According to redox cycle parameters, sildenafil significantly reduced blood glucose and pyruvate levels and the 3-hydroxybutyrate/acetoacetate ratio, while there was no significant effect on lactate, 3-hydroxybutyrate, acetoacetate and free fatty acid levels. Symptomatic transient hypotension was observed in two women. CONCLUSIONS: The ARTERIOFIL study has shown that a single 100 mg oral dose of sildenafil had a significant effect on increase in MWT but had no significant effects on PFWT and oxygenation parameters in patients with claudication. A double-blind, prospective, randomized, multicenter study (VIRTUOSE©) is ongoing to evaluate the chronic effect of six month-long sildenafil treatment on MWT in PAD patients with claudication. CLINICAL TRIAL REGISTRATION: This clinical trial was registered at clinicaltrials.gov, registration. number: NCT02832570, (https://clinicaltrials.gov/ct2/show/NCT02832570)

What are the differences among occupational groups related to their palliative care-specific educational needs and intensity of interprofessional collaboration in long-term care homes?

© 2017 The Author(s). Background: The purpose of this study was to compare the differences across occupational groups related to their end-of-life care-specific educational needs and reported intensity of interprofessional collaboration in long-term care (LTC) homes. Methods: A cross-sectional survey, based on two questionnaires, was administered at four LTC homes in Ontario, Canada using a modified Dilman’s approach. The first questionnaire, End of Life Professional Caregiver Survey, included three domains: patients and family-centered communication, cultural and ethical values, effective care delivery. The Intensity of Interprofessional Collaboration Scale included two subscales: care sharing activities, and interprofessional coordination. In total, 697 LTC staff were given surveys, including personal support workers, support staff (housekeeping, kitchen, recreation, laundry, dietician aids, office staff), and registered staff (licensed nurses, physiotherapists, social workers, pharmacists, physicians). Results: A total of 317 participants completed the survey (126 personal support workers, 109 support staff, 82 registered staff) for a response rate of 45%. Significant differences emerged among occupational groups across all scales and subscales. Specifically, support staff rated their comfort of working with dying patients significantly lower than both nurses and PSWs. Support staff also reported significantly lower ratings of care sharing activities and interprofessional coordination compared to both registered staff and personal support workers. Conclusions: These study findings suggest there are differing educational needs and sense of interprofessional collaboration among LTC staff, specific to discipline group. Both the personal support workers and support staff groups appeared to have higher needs for education; support staff also reported higher needs related to integration on the interdisciplinary team. Efforts to build capacity within support staff related to working with dying residents and their families are needed. Optimal palliative care may require resources to increase the availability of support for all staff involved in the care of patients

Efficient Passive ICS Device Discovery and Identification by MAC Address Correlation

Owing to a growing number of attacks, the assessment of Industrial Control Systems (ICSs) has gained in importance. An integral part of an assessment is the creation of a detailed inventory of all connected devices, enabling vulnerability evaluations. For this purpose, scans of networks are crucial. Active scanning, which generates irregular traffic, is a method to get an overview of connected and active devices. Since such additional traffic may lead to an unexpected behavior of devices, active scanning methods should be avoided in critical infrastructure networks. In such cases, passive network monitoring offers an alternative, which is often used in conjunction with complex deep-packet inspection techniques. There are very few publications on lightweight passive scanning methodologies for industrial networks. In this paper, we propose a lightweight passive network monitoring technique using an efficient Media Access Control (MAC) address-based identification of industrial devices. Based on an incomplete set of known MAC address to device associations, the presented method can guess correct device and vendor information. Proving the feasibility of the method, an implementation is also introduced and evaluated regarding its efficiency. The feasibility of predicting a specific device/vendor combination is demonstrated by having similar devices in the database. In our ICS testbed, we reached a host discovery rate of 100% at an identification rate of more than 66%, outperforming the results of existing tools.Comment: http://dx.doi.org/10.14236/ewic/ICS2018.

Implementation of chamber misalignments and deformations in the ATLAS muon spectrometer simulation

"The implementation of run-time dependent corrections for alignment and distortions in the detector description of the ATLAS Muon Spectrometer is discussed, along with the strategies for studying such effects in dedicated simulations."http://deepblue.lib.umich.edu/bitstream/2027.42/64214/1/jpconf8_119_032010.pd