The Role of Electron-electron Interactions in Graphene ARPES Spectra

We report on a theoretical study of the influence of electron-electron interactions on ARPES spectra in graphene that is based on the random-phase-approximation and on graphene's massless Dirac equation continuum model. We find that level repulsion between quasiparticle and plasmaron resonances gives rise to a gap-like feature at small k. ARPES spectra are sensitive to the electron-electron interaction coupling strength $\alpha_{\rm gr}$ and might enable an experimental determination of this material parameter.Comment: 5 Pages, 4 Figures, Submitte

Statistical Analysis of a Semilinear Hyperbolic System Advected by a White in Time Random Velocity Field

We study a system of semilinear hyperbolic equations passively advected by smooth white noise in time random velocity fields. Such a system arises in modeling non-premixed isothermal turbulent flames under single-step kinetics of fuel and oxidizer. We derive closed equations for one-point and multi-point probability distribution functions (PDFs) and closed form analytical formulas for the one point PDF function, as well as the two-point PDF function under homogeneity and isotropy. Exact solution formulas allows us to analyze the ensemble averaged fuel/oxidizer concentrations and the motion of their level curves. We recover the empirical formulas of combustion in the thin reaction zone limit and show that these approximate formulas can either underestimate or overestimate average concentrations when reaction zone is not tending to zero. We show that the averaged reaction rate slows down locally in space due to random advection induced diffusion; and that the level curves of ensemble averaged concentration undergo diffusion about mean locations.Comment: 18 page

Results and perspectives of the solar axion search with the CAST experiment

The status of the solar axion search with the CERN Axion Solar Telescope (CAST) will be presented. Recent results obtained by the use of $^3$He as a buffer gas has allowed us to extend our sensitivity to higher axion masses than our previous measurements with $^4$He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV$\le m_{a} \le$ 0.64 eV. From the absence of an excess of x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g$_{a\gamma} \le 2.3\times 10^{-10}$ GeV$^{-1}$ at 95% C.L., the exact value depending on the pressure setting. CAST published results represent the best experimental limit on the photon couplings to axions and other similar exotic particles dubbed WISPs (Weakly Interacting Slim Particles) in the considered mass range and for the first time the limit enters the region favored by QCD axion models. Preliminary sensitivities for axion masses up to 1.16 eV will also be shown reaching mean upper limits on the axion-photon coupling of g$_{a\gamma} \le 3.5\times 10^{-10}$ GeV$^{-1}$ at 95% C.L. Expected sensibilities for the extension of the CAST program up to 2014 will be presented. Moreover long term options for a new helioscope experiment will be evoked.Comment: 4 pages, 2 pages, to appear in the proceedings of the 24th Rencontres de Blois V2 A few affiliations were not corrected in previous version V3 Author adde

Electrocardiogram Monitoring Wearable Devices and Artificial-Intelligence-Enabled Diagnostic Capabilities: A Review

Worldwide, population aging and unhealthy lifestyles have increased the incidence of high-risk health conditions such as cardiovascular diseases, sleep apnea, and other conditions. Recently, to facilitate early identification and diagnosis, efforts have been made in the research and development of new wearable devices to make them smaller, more comfortable, more accurate, and increasingly compatible with artificial intelligence technologies. These efforts can pave the way to the longer and continuous health monitoring of different biosignals, including the real-time detection of diseases, thus providing more timely and accurate predictions of health events that can drastically improve the healthcare management of patients. Most recent reviews focus on a specific category of disease, the use of artificial intelligence in 12-lead electrocardiograms, or on wearable technology. However, we present recent advances in the use of electrocardiogram signals acquired with wearable devices or from publicly available databases and the analysis of such signals with artificial intelligence methods to detect and predict diseases. As expected, most of the available research focuses on heart diseases, sleep apnea, and other emerging areas, such as mental stress. From a methodological point of view, although traditional statistical methods and machine learning are still widely used, we observe an increasing use of more advanced deep learning methods, specifically architectures that can handle the complexity of biosignal data. These deep learning methods typically include convolutional and recurrent neural networks. Moreover, when proposing new artificial intelligence methods, we observe that the prevalent choice is to use publicly available databases rather than collecting new data

Study protocol : improving newborn survival in rural southern Tanzania : a cluster-randomised trial to evaluate the impact of a scaleable package of interventions at community level with health system strengthening

Child mortality has declined substantially in many countries including Tanzania, but newborn mortality remains high and around 3 million babies die every year in the first 28 days of life. Community-based approaches with home visits in the first week of life have shown great potential to reduce newborn mortality. INSIST aimed1 to develop, implement and evaluate an integrated, two-part strategy that combines interventions at community level with health system strengthening in rural Southern Tanzania to reduce newborn mortality. The community intervention focused around interpersonal communication through home visits in pregnancy and the early neonatal period by a village-based "agent of change". Key messages focused on hygiene during delivery, immediate and exclusive breastfeeding, and identification and extra care for babies born small because of low birth weight or prematurity. Extra care for babies born small included skin-to-skin care for small babies and referral to hospital for very small babies. The community intervention was implemented in six poor rural districts in Southern Tanzania, with 65 of the 132 wards within these districts randomized to receive the community intervention. In addition, a health system quality-improvement package was implemented in all health facilities of one district. Data collection for the evaluation included i) a baseline household survey in 2007 of all 243,000 households in 5 of the 6 study districts to estimate baseline mortality and prevalence of newborn care behaviours, ii) an adequacy survey in 2011 in a representative sample of 5,000 households to estimate coverage of home visits and prevalence of newborn care behaviours, and iii) an endline household survey in 2013 in a representative sample of 200,000 households to estimate newborn and maternal mortality and prevalence of newborn care behaviours. The final analysis was based on "intention to treat", comparing newbor

Anomaly Detection for Vision-based Railway Inspection

none7nomixedRiccardo Gasparini; Stefano Pini; Guido Borghi; Giuseppe Scaglione; Simone Calderara; Eugenio Fedeli; Rita CucchiaraRiccardo Gasparini; Stefano Pini; Guido Borghi; Giuseppe Scaglione; Simone Calderara; Eugenio Fedeli; Rita Cucchiar

Nonadiabatic effects in a generalized Jahn-Teller lattice model: heavy and light polarons, pairing and metal-insulator transition

The ground state polaron potential of 1D lattice of two-level molecules with spinless electrons and two Einstein phonon modes with quantum phonon-assisted transitions between the levels is found anharmonic in phonon displacements. The potential shows a crossover from two nonequivalent broad minima to a single narrow minimum corresponding to the level positions in the ground state. Generalized variational approach implies prominent nonadiabatic effects:(i) In the limit of the symmetric E-e Jahn- Teller situation they cause transition between the regime of the predominantly one-level "heavy" polaron and a "light" polaron oscillating between the levels due to phonon assistance with almost vanishing polaron displacement. It implies enhancement of the electron transfer due to decrease of the "heavy" polaron mass (undressing) at the point of the transition. Pairing of "light" polarons due to exchange of virtual phonons occurs. Continuous transition to new energy ground state close to the transition from "heavy" polaron phase to "light" (bi)polaron phase occurs. In the "heavy" phase, there occurs anomalous (anharmonic) enhancements of quantum fluctuations of the phonon coordinate, momentum and their product as functions of the effective coupling. (ii) Dependence of the polaron mass on the optical phonon frequency appears.(iii) Rabi oscillations significantly enhance quantum shift of the insulator-metal transition line to higher values of the critical effective e-ph coupling supporting so the metallic phase. In the E-e JT case, insulator-metal transition coincide with the transition between the "heavy" and the "light" (bi)polaron phase at certain (strong) effective e-ph interaction.Comment: Paper in LaTex format (file jtseptx.tex) and 9 GIF-figures (ppic_1.gif,...ppic_9.gif

Solar axion search with the CAST experiment

The CAST (CERN Axion Solar Telescope) experiment is searching for solar axions by their conversion into photons inside the magnet pipe of an LHC dipole. The analysis of the data recorded during the first phase of the experiment with vacuum in the magnet pipes has resulted in the most restrictive experimental limit on the coupling constant of axions to photons. In the second phase, CAST is operating with a buffer gas inside the magnet pipes in order to extent the sensitivity of the experiment to higher axion masses. We will present the first results on the $^{4}{\rm He}$ data taking as well as the system upgrades that have been operated in the last year in order to adapt the experiment for the $^{3}{\rm He}$ data taking. Expected sensitivities on the coupling constant of axions to photons will be given for the recent $^{3}{\rm He}$ run just started in March 2008.Comment: Proceedings of the ICHEP 2008 conferenc

CAST solar axion search with 3^He buffer gas: Closing the hot dark matter gap

The CERN Axion Solar Telescope (CAST) has finished its search for solar axions with 3^He buffer gas, covering the search range 0.64 eV < m_a <1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess X-rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g_ag < 3.3 x 10^{-10} GeV^{-1} at 95% CL, with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of g_a, for example by the currently discussed next generation helioscope IAXO.Comment: 5 pages, 2 figures. Last version uploade

Search for low Energy solar Axions with CAST

We have started the development of a detector system, sensitive to single photons in the eV energy range, to be suitably coupled to one of the CAST magnet ports. This system should open to CAST a window on possible detection of low energy Axion Like Particles emitted by the sun. Preliminary tests have involved a cooled photomultiplier tube coupled to the CAST magnet via a Galileian telescope and a switched 40 m long optical fiber. This system has reached the limit background level of the detector alone in ideal conditions, and two solar tracking runs have been performed with it at CAST. Such a measurement has never been done before with an axion helioscope. We will present results from these runs and briefly discuss future detector developments.Comment: Paper submitted to the proceedings of the "4th Patras Workshop on Axions, WIMPs and WISPs", DESY, Hamburg Site - Germany, 18-21 June 2008. Author affiliations are reported on the title page of the paper. In version 2: 1 affiliation change, 3 references adde