Discovery of the compact X-ray source inside the Cygnus Loop

We detected an X-ray compact source inside the Cygnus Loop during the observation project of the whole Cygnus Loop with the ASCA GIS. The source intensity is 0.11 c s$^{-1}$ for GIS and 0.15 c s$^{-1}$ for SIS, which is the strongest in the ASCA band. The X-ray spectra are well fitted by a power law spectrum of a photon index of \error{-2.1}{0.1} with neutral H column of (\error{3.1}{0.6})${\rm \times 10^{21} cm^{-2}}$. Taking into account the interstellar absorption feature, this source is X-ray bright mainly above 1 keV suggesting either an AGN or a rotating neutron star. So far, we did not detect intensity variation nor coherent pulsation mainly due to the limited observation time. There are several optical bright stellar objects within the error region of the X-ray image. We carried out the optical spectroscopy for the brightest source (V=+12.6) and found it to be a G star. The follow up deep observation both in optical and in X-ray wavelengths are strongly required.Comment: Accepted for Publications of the Astronomical Society of Japan 17 pages, 3 figur

A comparison of CMB- and HLA-based approaches to type I interoperability reference model problems for COTS-based distributed simulation

Commercial-off-the-shelf (COTS) simulation packages (CSPs) are software used by many simulation modellers to build and experiment with models of various systems in domains such as manufacturing, health, logistics and commerce. COTS distributed simulation deals with the interoperation of CSPs and their models. Such interoperability has been classified into six interoperability reference models. As part of an on-going standardisation effort, this paper introduces the COTS Simulation Package Emulator, a proposed benchmark that can be used to investigate Type I interoperability problems in COTS distributed simulation. To demonstrate its use, two approaches to this form of interoperability are discussed, an implementation of the CMB conservative algorithm, an example of a so-called “light” approach, and an implementation of the HLA TAR algorithm, an example of a so-called “heavy” approach. Results from experimentation over four federation topologies are presented and it is shown the HLA approach out performs the CMB approach in almost all cases. The paper concludes that the CSPE benchmark is a valid basis from which the most efficient approach to Type I interoperability problems for COTS distributed simulation can be discovered

Spectroscopic Monitoring Observations of Nova V1724 Aql in 2012

Spectroscopic and photometric monitoring observations of nova Apl 2012 (V1724 Apl) were conducted at Koyama Astronomical Observatory, Fujii-Kurosaki Observatory and Bisei Astronomical Observatory. The nova was initially considered as an outbursting pre-main-sequence young stellar object. Our monitoring observations have revealed the nova to be a Fe II type classical nova. The temporal evolution of spectra and light curves of the nova were similar to those of a slow nova (e.g., V1280 Sco and V5558 Sgr). We observed no evidence of molecule formation in V1724 Aql in contrast with V2676 Oph in which dust formation occurred after the molecular formation in the nova outflow

Survey and classification of functional characteristics in neural network technique for the diagnosis of ischemic heart disease: A systematic review

Background: Nowadays, the prevalence of ischemic heart diseases (IHDs) leads to destructive effects such as patient death. Late diagnosis of such diseases as well as their invasive diagnostic approaches made researchers provide a decision support system based on neural network techniques, while using minimum data set for timely diagnosis. In this regard, selecting minimum useful features is significant for designing neural network structure and it paves the way to attain maximum accuracy in obtaining the results. Methods: In this systematic review, valid databases using sensitive keywords were initially searched out to find articles related to "diagnosing the ischemic heart disease using artificial neural networks" and afterwards, scientific methods were used to analyze and classify the content. Findings: Researchers applied various extractable features from demographic data, medical history, signs and symptoms, and paraclinical examinations, to design the neural network structure. Among them, the features obtained from electrocardiographic test, embedded in paraclinical examinations, had led to a remarkable increase of efficiency in neural network. Conclusion: Utilizing such diagnostic decision support systems in practical environments depends on their high confidence coefficient and physicians� acceptability. Therefore, it can be useful to improve maturity in the design of the neural network structure depending on the choice of the minimum optimal features, and to create required infrastructures to input patients� real, accurate, and flowing data in these systems. © 2018, Isfahan University of Medical Sciences(IUMS). All rights reserved

Survey and classification of functional characteristics in neural network technique for the diagnosis of ischemic heart disease: A systematic review

Background: Nowadays, the prevalence of ischemic heart diseases (IHDs) leads to destructive effects such as patient death. Late diagnosis of such diseases as well as their invasive diagnostic approaches made researchers provide a decision support system based on neural network techniques, while using minimum data set for timely diagnosis. In this regard, selecting minimum useful features is significant for designing neural network structure and it paves the way to attain maximum accuracy in obtaining the results. Methods: In this systematic review, valid databases using sensitive keywords were initially searched out to find articles related to "diagnosing the ischemic heart disease using artificial neural networks" and afterwards, scientific methods were used to analyze and classify the content. Findings: Researchers applied various extractable features from demographic data, medical history, signs and symptoms, and paraclinical examinations, to design the neural network structure. Among them, the features obtained from electrocardiographic test, embedded in paraclinical examinations, had led to a remarkable increase of efficiency in neural network. Conclusion: Utilizing such diagnostic decision support systems in practical environments depends on their high confidence coefficient and physicians� acceptability. Therefore, it can be useful to improve maturity in the design of the neural network structure depending on the choice of the minimum optimal features, and to create required infrastructures to input patients� real, accurate, and flowing data in these systems. © 2018, Isfahan University of Medical Sciences(IUMS). All rights reserved

Near-infrared Observations of Nova V574 Puppis (2004)

We present results obtained from extensive near-infrared spectroscopic and photometric observations of nova V574 Pup during its 2004 outburst. The observations were obtained over four months, starting from 2004 November 25 (four days after the nova outburst) to 2005 March 20. The near-IR JHK light curve is presented - no evidence is seen from it for dust formation to have occurred during our observations. In the early decline phase, the JHK spectra of the nova are dominated by emission lines of hydrogen Brackett and Paschen series, OI, CI and HeI. We also detect the fairly uncommon Fe II line at 1.6872 micron in the early part of our observations. The strengths of the HeI lines at 1.0830 micron and 2.0585 micron are found to become very strong towards the end of the observations indicating a progression towards higher excitation conditions in the nova ejecta. The width of the emission lines do not show any significant change during the course of our observations. The slope of the continuum spectrum was found to have a lambda^{-2.75} dependence in the early stages which gradually becomes flatter with time and changes to a free-free spectral dependence towards the later stages. Recombination analysis of the HI lines shows deviations from Case B conditions during the initial stages. However, towards the end of our observations, the line strengths are well simulated with case B model values with electron density n_e = 10^{9-10} cm^{-3} and a temperature equal to 10^4 K. Based on our distance estimate to the nova of 5.5 kpc and the observed free-free continuum emission in the later part of the observations, we estimate the ionized mass of the ejecta to be between 10^{-5} and 10^{-6} solar-mass.Comment: 10 pages, 8 figures, Accepted for publication in MNRA

On the Progenitor System of Nova V2491 Cygni

Nova V2491 Cyg is one of just two detected pre-outburst in X-rays. The light curve of this nova exhibited a rare "re-brightening" which has been attributed by some as the system being a polar, whilst others claim that a magnetic WD is unlikely. By virtue of the nature of X-ray and spectroscopic observations the system has been proposed as a recurrent nova, however the adoption of a 0.1 day orbital period is generally seen as incompatible with such a system. In this research note we address the nature of the progenitor system and the source of the 0.1 day periodicity. Through the combination of Liverpool Telescope observations with published data and archival 2MASS data we show that V2491 Cyg, at a distance of 10.5 - 14 kpc, is likely to be a recurrent nova of the U Sco-class; containing a sub-giant secondary and an accretion disk, rather than accretion directly onto the poles. We show that there is little evidence, at quiescence, supporting a ~ 0.1 day periodicity, the variation seen at this stage is likely caused by flickering of a re-established accretion disk. We propose that the periodicity seen shortly after outburst is more likely related to the outburst rather than the - then obscured - binary system. Finally we address the distance to the system, and show that a significantly lower distance (~ 2 kpc) would result in a severely under-luminous outburst, and as such favour the larger distance and the recurrent nova scenario.Comment: 5 pages, 3 images, accepted for publication in A&A as a research not

Probing the phase transition to a coherent 2D Kondo Lattice

Kondo lattices are systems with unusual electronic properties that stem from strong electron correlation, typically studied in intermetallic 3D compounds containing lanthanides or actinides. Lowering the dimensionality of the system enhances the role of electron correlations providing a new tuning knob for the search of novel properties in strongly correlated quantum matter. The realization of a 2D Kondo lattice by stacking a single-layer Mott insulator on a metallic surface is reported. The temperature of the system is steadily lowered and by using high-resolution scanning tunneling spectroscopy, the phase transition leading to the Kondo lattice is followed. Above 27 K the interaction between the Mott insulator and the metal is negligible and both keep their original electronic properties intact. Below 27 K the Kondo screening of the localized electrons in the Mott insulator begins and below 11 K the formation of a coherent quantum electronic state extended to the entire sample, i.e., the Kondo lattice, takes place. By means of density functional theory, the electronic properties of the system and its evolution with temperature are explained. The findings contribute to the exploration of unconventional states in 2D correlated materialsThis work was supported by Ministerio de Ciencia, Innovación y Universidades through grants, PID2021-128011NB-I00 and PID2019-105458RBI00. Ministerio de Ciencia e Innovación and Comunidad de Madrid through grants “Materiales Disruptivos Bidimensionales (2D)” (MAD2DCM)-UAM and “Materiales Disruptivos Bidimensionales (2D)” (MAD2DCM)-IMDEA-NC funded by the Recovery, Transformation and Resilience Plan, and by NextGenerationEU from the European Union. Comunidad de Madrid through grants NMAT2D-CM P20128/NMT-4511 and NanoMagCost. IMDEA Nanoscience acknowledges support from the “‘Severo Ochoa”’ Programme for Centres of Excellence in R&D CEX2020-001039-S. IFIMAC acknowledges support from the “‘María de Maeztu”’ Programme for Units of Excellence in R&D CEX2018-000805-M. M.G. thanks Ministerio de Ciencia, Innovación y Universidades “Ramón y Cajal” Fellowship RYC2020-029317-I. Allocation of computing time at the Centro de Computación Científica at the Universidad Autónoma de Madrid, the CINECA Consortium INF16_npqcd Project, and Newton HPCC Computing Facility at the University of Calabria (MP

Observation of the first gravitational microlensing event in a sparse stellar field : the Tago event

We report the observation of the first gravitational microlensing event in a sparse stellar field, involving the brightest (V=11.4 mag) andclosest (~ 1 kpc) source star to date. This event was discovered by an amateurastronomer, A. Tago, on 2006 October 31 as a transient brightening, by ~4.5 mag during a ~15 day period, of a normal A-type star (GSC 3656-1328) in the Cassiopeia constellation. Analysis of both spectroscopic observations and the light curve indicates that this event was caused by gravitational microlensing rather than an intrinsically variable star. Discovery of this single event over a 30 year period is roughly consistent with the expected microlensing rate for the whole sky down to V = 12 mag stars. However, the probability for finding events with such a high magnification (~ 50) is much smaller, by a factor ~1/50, which implies that the true event rate may be higher than expected. This discovery indicates the potential of all sky variability surveys, employing frequent sampling by telescopes with small apertures and wide fields of view, for finding such rare transient events, and using the observations to explore galactic disk structure and search for exo-planets.Comment: 13 pages, 2 tables, 3 figures, accepted by Ap