Lattices of quasi-equational theories as congruence lattices of semilattices with operators, Part I

We show that for every quasivariety K of structures (where both functions and relations are allowed) there is a semilattice S with operators such that the lattice of quasi-equational theories of K (the dual of the lattice of sub-quasivarieties of K) is isomorphic to Con(S,+,0,F). As a consequence, new restrictions on the natural quasi-interior operator on lattices of quasi-equational theories are found.Comment: Presented on International conference "Order, Algebra and Logics", Vanderbilt University, 12-16 June, 2007 25 pages, 2 figure

Sgoldstino events in top decays at LHC

We study top-quark decays in models with light sgoldstinos. The off-diagonal entries in the squark mass matrices can lead to FCNC top two-body decays into sgoldstinos and u(c) quarks. We compute the rates for these decays and discuss the corresponding signatures that could manifest the presence of sgoldstinos in top decays at LHC. We expect that a supersymmetry breaking scale $\sqrt{F}$ up to a scale of order 10 TeV could be probed through this process, for a maximal squark mixing with the third generation. Justified by our preliminary analysis, a thorough study of the corresponding signal versus background and systematics in the LHC environment would be most welcome, in order to accurately assess the potential of this promising process in determining $\sqrt{F}$.Comment: Standard LaTeX, 11 pages, 4 figures, one reference adde

A Lagrangian model of the evolution of the particulate size distribution of vehicular emissions

The emission inventory for London indicates that nearly 80% of the particulate emissions derive from vehicular sources. Most of this mass is in the form of ultrafine submicrometer particles which are of concern because of their influence on lung function. The prediction of their dispersion in the atmosphere coupled to the physical and chemical transformations which affect their size distribution and concentration are of great importance. This paper reports the first results from a new meso-scale Lagrangian model which follows the particulate emissions and the evolution of their size distribution across the city. The vehicular emissions are based on the published inventory, corrected to time of day, while other emissions are assumed steady. The initial size distributions of background and emitted particles are represented by the sum of three lognormal distributions. Meteorological data are derived from Meteorological Office reports and are preprocessed to obtain the hourly values of boundary layer depth, Monin–Obukov (MO) length, friction velocity, etc., needed for the computation of the vertical dispersion process via eddy diffusivities and the aerodynamic component of the dry deposition process. In the vertical direction, three layers are assumed—surface layer (typically 50 m), canopy layer and one further layer up to the prevailing boundary layer depth. Currently, the model includes wet and dry deposition and coagulation but not chemical reaction, nucleation or deliquescence. Trajectories are evolved for several hours across the city and the number size distributions and mass concentrations (PM10, PM2.5, PM1 and PM0.1) output at each step. This enables the vehicular contributions over and above the background concentration in each size range to be studied in detail. Data from the model have been compared with experimental data for one of the London background sites where particle number size distribution up to 450 nm (SMPS), plus PM10 and PM2.5 (TEOM) data are available

TeV gamma-UHECR anisotropy by decaying nuclei in flight: first neutrino traces?

Ultra High Cosmic Rays) made by He-like lightest nuclei might solve the AUGER extragalactic clustering along Cen A. Moreover He like UHECR nuclei cannot arrive from Virgo because the light nuclei fragility and opacity above a few Mpc, explaining the Virgo UHECR absence. UHECR signals are spreading along Cen-A as observed because horizontal galactic arms magnetic fields, bending them on vertical angles. Cen A events by He-like nuclei are deflected as much as the observed clustered ones; proton will be more collimated while heavy (iron) nuclei are too much dispersed. Such a light nuclei UHECR component coexist with the other Auger heavy nuclei and with the Hires nucleon composition. Remaining UHECR spread group may hint for correlations with other gamma (MeV-Al^{26} radioactive) maps, mainly due to galactic SNR sources as Vela pulsar, the brightest, nearest GeV source. Other nearest galactic gamma sources show links with UHECR via TeV correlated maps. We suggest that UHECR are also heavy radioactive galactic nuclei as Ni^{56}, Ni^{57} and Co^{60} widely bent by galactic fields. UHECR radioactivity (in $\beta$ and $\gamma$ channels) and decay in flight at hundreds keV is boosted (by huge Lorentz factor (nearly a billion) leading to PeVs electrons and consequent synchrotron TeVs gamma offering UHECR-TeV correlated sky anisotropy. Moreover also rarest and non-atmospheric electron and tau neutrinos secondaries at PeVs, as the first two rarest shower just discovered in ICECUBE, maybe the first signature of such expected radioactive secondary tail.Comment: 7 pages,3 figures. arXiv admin note: substantial text overlap with arXiv:1201.015

Instabilities for a relativistic electron beam interacting with a laser irradiated plasma

The effects of a radiation field (RF) on the unstable modes developed in relativistic electron beam--plasma interaction are investigated assuming that $\omega_{0} >\omega_{p}$, where $\omega_{0}$ is the frequency of the RF and $\omega_{p}$ is the plasma frequency. These unstable modes are parametrically coupled to each other due to the RF and are a mix between two--stream and parametric instabilities. The dispersion equations are derived by the linearization of the kinetic equations for a beam--plasma system as well as the Maxwell equations. In order to highlight the effect of the radiation field we present a comparison of our analytical and numerical results obtained for nonzero RF with those for vanishing RF. Assuming that the drift velocity $\mathbf{u}_{b}$ of the beam is parallel to the wave vector $\mathbf{k}$ of the excitations two particular transversal and parallel configurations of the polarization vector $\mathbf{E}_{0}$ of the RF with respect to $\mathbf{k}$ are considered in detail. It is shown that in both geometries resonant and nonresonant couplings between different modes are possible. The largest growth rates are expected at the transversal configuration when $\mathbf{E}_{0}$ is perpendicular to $\mathbf{k}$. In this case it is demonstrated that in general the spectrum of the unstable modes in $\omega$--$k$ plane is split into two distinct domains with long and short wavelengths, where the unstable modes are mainly sensitive to the beam or the RF parameters, respectively. In parallel configuration, $\mathbf{E}_{0} \parallel \mathbf{k}$, and at short wavelengths the growth rates of the unstable modes are sensitive to both beam and RF parameters remaining insensitive to the RF at long wavelengths.Comment: 23 pages, 5 figure

Сравнение энергетической эффективности дефибрилляционных импульсов на базе гипотезы гарантированной дефибрилляции

The aim of this study is to compare, on the basis of the guaranteed defibrillation hypothesis, the energy efficiency of a trapezoidal defibrillation pulse with fixed rise and fall times with the main types of defibrillation pulses: truncated exponential with the tilt of 50%, rectangular and half-sine. The study was carried out using the ten Tusscher–Panfilov 2006 human ventricular myocyte model subjected to simulated fibrillation in the BeatBox simulation environment. Depolarizing excitation stimuli with a high frequency were used to simulate fibrillation. The results of computer simulation based on the hypothesis of the guaranteed defibrillation showed that defibrillation pulses are energetically efficient (have low values of threshold energy of defibrillation) in a rather narrow range of phase duration values, beyond which a rapid increase in the threshold energy is observed. In terms of energy efficiency, the trapezoidal pulse with the sloping rise and fall is very close to the half-sine one, and at the same time it has a wider range of energetically effective durations.Significantly higher minimum threshold energy of guaranteed defibrillation is a characteristic of rectangular and truncated exponential pulses, while the truncated exponential pulse has a more uniform characteristic in the area of energetically effective durations. From the results obtained, it can be assumed that the maximum duration of the phases of the defibrillation pulse should be limited to the value of no more than 9ms. In this case, the nominal delivered energy at the load impedance of 175Ω should be at least 140J. The possibility of increasing the pulse duration without a significant drop in its energy efficiency will ensure the delivery of more energy in patients with high transthoracic impedance and, accordingly, a greater probability of successful defibrillation. The above will also increase the probability of successful defibrillation in patients with defibrillation electrodes placement errors. Gorbunov B. B., Vostrikov V. A., Nesterenko I. V., Telyshev D. V. Comparison of the energy efficiency of defibrillation pulses based on the hypothesis of guaranteed defibrillation. Ural Radio Engineering Journal. 2021;5(4):353–368. (In Russ.) DOI: 10.15826/urej.2021.5.4.002.Целью данного исследования является сравнение на основе гипотезы гарантированной дефибрилляции энергетической эффективности биполярного трапецеидального импульса с фиксированной длительностью фронта и среза с основными типами дефибрилляционных импульсов: классической трапецеидальной (truncated exponential) со спадом вершины 50%, прямоугольной и полусинусоидальной. Результаты компьютерного моделирования на базе гипотезы гарантированной дефибрилляции показали, что дефибрилляционные импульсы энергетически эффективны (имеют низкие значения пороговой энергии дефибрилляции) в достаточно узком диапазоне значений длительности фаз, за пределами которого наблюдается быстрый рост пороговой энергии. По энергетической эффективности трапецеидальный импульс с пологими фронтом и срезом очень близок к полусинусоидальному, и при этом он имеет более широкий диапазон энергетически эффективных длительностей. Существенно более высокую минимальную пороговую энергию гарантированной дефибрилляции имеют прямоугольный и классический трапецеидальный со спадом вершины 0,5 импульсы, при этом классический трапецеидальный импульс имеет более равномерную характеристику в области энергетически эффективных длительностей. Из полученных результатов можно предположить, что максимальную длительность фаз дефибрилляционного импульса следует ограничивать значением не более 9 мс. При этом номинальная выделенная энергия на сопротивлении нагрузки 175 Ом должна составлять не менее 140 Дж. Возможность увеличения длительности импульса без значимого падения его энергетической эффективности позволит обеспечить выделение большей энергии у больных с высоким сопротивлением грудной клетки и, соответственно, большую вероятность проведения успешной дефибрилляции. Указанное выше увеличит также вероятность проведения успешной дефибрилляции у больных при ошибках наложения дефибрилляционных электродов или использовании сухих многоразовых дефибрилляционных электродов. Горбунов Б.Б., Востриков В.А., Нестеренко И.В., Телышев Д.В. Сравнение энергетической эффективности дефибрилляционных импульсов на базе гипотезы гарантированной дефибрилляции. Ural Radio Engineering Journal. 2021;5(4):353–368. DOI: 10.15826/urej.2021.5.4.002.

Resolution of puzzles from the LSND, KARMEN, and MiniBooNE experiments

This work has attempted to reconcile puzzling neutrino oscillation results from the LSND, KARMEN and MiniBooNE experiments. We show that the LSND evidence for $\bar{\nu}_\mu \to \bar{\nu}_e$ oscillations, its long-standing disagreement with the results from KARMEN, and the anomalous event excess observed by MiniBooNE in $\nu_\mu$ and $\bar{\nu}_\mu$ data could all be explained by the existence of a heavy sterile neutrino ($\nu_h$). All these results are found to be consistent with each other assuming that the $\nu_h$ is created in $\nu_\mu$ neutral-current interactions and decays radiatively into a photon and a light neutrino. Assuming the $\nu_h$ is produced through mixing with $\nu_\mu$, the combined analysis of the LSND and MiniBooNe excess events suggests that the $\nu_h$ mass is in the range from 40 to 80 MeV, the mixing strength is $|U_{\mu h}|^2 \simeq 10^{-3}-10^{-2}$, and the lifetime is $\tau_{\nu_h} \lesssim 10^{-9}$ s. Surprisingly, this LSND-MiniBooNE parameters window is found to be unconstrained by the results from the most sensitive experiments searching for heavy neutrino. We set new limits on $|U_{\mu h}|^2$ for the LSND-MiniBooNE favorable mass region from the precision measurements of the Michel spectrum by the TWIST experiment. The results obtained provide a strong motivation for a sensitive search for the $\nu_h$ in a near future $K$ decay or neutrino experiments, which fit well in the existing/planned experimental programs at CERN or FNAL. The question of whether the heavy neutrino is Dirac or Majorana particle is briefly discussed.Comment: 24 pages, 28 figures, version to appear in PR