Magnetospheric accretion-ejection processes in the classical T Tauri star AA

From a long time series of high resolution (R=115,000) HARPS spectra and simultaneous broad-band photometry, we report new evidence for magnetospheric accretion as well as ejection processes in the nearly edge-on classical T Tauri star AA Tau. AA Tau's light curve is modulated with a period of 8.22d. The recurrent luminosity dips are due to the periodic occultation of the central star by the magnetically-warped inner disk edge located at about 9 Rstar. Balmer line profiles exhibit a clear rotational modulation of high-velocity redshifted absorption components with a period of 8.22 days as well, with a maximum strength when the main accretion funnel flow passes through the line of sight. At the same time, the luminosity of the system decreases by about 1 mag, indicative of circumstellar absorption of the stellar photosphere by the magnetically-warped, corotating inner disk edge. The photospheric and HeI radial velocities also exhibit periodic variations, and the veiling is modulated by the appearance of the accretion shock at the bottom of the accretion funnel. Diagnostics of hot winds and their temporal behaviour are also presented. The peculiar geometry of the young AA Tau system (nearly edge-on) allows us to uniquely probe the acretion-ejection region close to the star. We find that most spectral and photometric diagnostics vary as expected from models of magnetically-channelled accretion in young stars, with a large scale magnetosphere tilted by 20 deg onto the star's spin axis. We also find evidence for time variability of the magnetospheric accretion flow on a timescale of a few rotational periods.Comment: 14 page

Magnetization of manganite thin films on ferroelectric substrates

© 2016 Elsevier B.V.Here we report the magnetic susceptibility measurements of magnetron sputtered orthorhombic manganite RMnO3 (R=Yb, Gd) thin films deposited on dielectric LaAlO3 and ferroelectric SrTiO3, LiNbO3 substrates. We observed that all of investigated o-RMnO3 films show a splitting in the temperature dependence of ZFC and FC magnetization curves. We found that the substrate can impact on the splitting temperature ZFC-FC curves and absolute value of the magnetization of thin films

Magnetization of manganite thin films on ferroelectric substrates

© 2016 Elsevier B.V.Here we report the magnetic susceptibility measurements of magnetron sputtered orthorhombic manganite RMnO3 (R=Yb, Gd) thin films deposited on dielectric LaAlO3 and ferroelectric SrTiO3, LiNbO3 substrates. We observed that all of investigated o-RMnO3 films show a splitting in the temperature dependence of ZFC and FC magnetization curves. We found that the substrate can impact on the splitting temperature ZFC-FC curves and absolute value of the magnetization of thin films

Magnetic and dielectric properties of o-LuFeO<inf>3</inf>/SrTiO<inf>3</inf>

© 2016 Published under licence by IOP Publishing Ltd. Here we present the investigation of the orthorhombic o-LuFeO 3 thin film grown on SrTiO 3 (001) substrate. Temperature dependencies of magnetization measured in magnetic fields 1000 Oe and 2000 Oe were described in the assumption that ferromagnetic correlated regions are presented in samples together with the paramagnetic phase. Additional argument in favor of the ferromagnetic regions existence in o-LuFeO 3 is the magnetic hysteresis curve measured at T=5 and 100K. The temperature dependences of dielectric response were measured and analyzed

The correlated optical and radio variability of BL Lacertae. WEBT data analysis 1994-2005

Since 1997, BL Lacertae has undergone a phase of high optical activity, with the occurrence of several prominent outbursts. Starting from 1999, the Whole Earth Blazar Telescope (WEBT) consortium has organized various multifrequency campaigns on this blazar, collecting tens of thousands of data points. One of the main issues in the study of this huge dataset has been the search for correlations between the optical and radio flux variations, and for possible periodicities in the light curves. The analysis of the data assembled during the first four campaigns (comprising also archival data to cover the period 1968-2003) revealed a fair optical-radio correlation in 1994-2003, with a delay of the hard radio events of ~100 days. Moreover, various statistical methods suggested the existence of a radio periodicity of ~8 years. In 2004 the WEBT started a new campaign to extend the dataset to the most recent observing seasons, in order to possibly confirm and better understand the previous results. In this campaign we have collected and assembled about 11000 new optical observations from twenty telescopes, plus near-IR and radio data at various frequencies. Here, we perform a correlation analysis on the long-term R-band and radio light curves. In general, we confirm the ~100-day delay of the hard radio events with respect to the optical ones, even if longer (~200-300 days) time lags are also found in particular periods. The radio quasi-periodicity is confirmed too, but the "period" seems to progressively lengthen from 7.4 to 9.3 years in the last three cycles. The optical and radio behaviour in the last forty years suggests a scenario where geometric effects play a major role. In particular, the alternation of enhanced and suppressed optical activity (accompanied by hard and soft radio events, respectively) canComment: 6 pages, 4 figure

Multifrequency variability of the blazar AO 0235+164. The WEBT campaign in 2004-2005 and long-term SED analysis

A huge multiwavelength campaign targeting the blazar AO 0235+164 was organized by the Whole Earth Blazar Telescope (WEBT) in 2003-2005 to study the variability properties of the source. Monitoring observations were carried out at cm and mm wavelengths, and in the near-IR and optical bands, while three pointings by the XMM-Newton satellite provided information on the X-ray and UV emission. We present the data acquired during the second observing season, 2004-2005, by 27 radio-to-optical telescopes. They reveal an increased near-IR and optical activity with respect to the previous season. Increased variability is also found at the higher radio frequencies, down to 15 GHz, but not at the lower ones. The radio (and optical) outburst predicted to peak around February-March 2004 on the basis of the previously observed 5-6 yr quasi-periodicity did not occur. The analysis of the optical light curves reveals now a longer characteristic time scale of 8 yr, which is also present in the radio data. The spectral energy distributions corresponding to the XMM-Newton observations performed during the WEBT campaign are compared with those pertaining to previous pointings of X-ray satellites. Bright, soft X-ray spectra can be described in terms of an extra component, which appears also when the source is faint through a hard UV spectrum and a curvature of the X-ray spectrum. Finally, there might be a correlation between the X-ray and optical bright states with a long time delay of about 5 yr, which would require a geometrical interpretation.Comment: 14 pages, 10 figures (8 included in the text and 2 PNG files), in press for A&

Testing the inverse-Compton catastrophe scenario in the intra-day variable blazar S5 0716+71. I. Simultaneous broadband observations during November 2003

Some intra-day variable, compact extra-galactic radio sources show brightness temperatures severely exceeding 10^{12} K, the limit set by catastrophic inverse-Compton (IC) cooling in sources of incoherent synchrotron radiation. The violation of the IC limit, possible under non-stationary conditions, would lead to IC avalanches in the soft-gamma-ray energy band during transient periods. For the first time, broadband signatures of possible IC catastrophes were searched for in S5 0716+71. A multifrequency observing campaign targetting S5 0716+71 was carried out in November 2003 under the framework of the European Network for the Investigation of Galactic nuclei through Multifrequency Analysis (ENIGMA) together with a campaign by the Whole Earth Blazar Telescope (WEBT), involving a pointing by the soft-gamma-ray satellite INTEGRAL, optical, near-infrared, sub-millimeter, millimeter, radio, and Very Long Baseline Array (VLBA) monitoring. S5 0716+71 was very bright at radio frequencies and in a rather faint optical state during the INTEGRAL pointing; significant inter-day and low intra-day variability was recorded in the radio regime, while typical fast variability features were observed in the optical band. No correlation was found between the radio and optical emission. The source was not detected by INTEGRAL, neither by the X-ray monitor JEM-X nor by the gamma-ray imager ISGRI, but upper limits to the source emission in the 3-200 keV energy band were estimated. A brightness temperature Tb>2.1x10^{14} K was inferred from the radio variability, but no corresponding signatures of IC avalanches were recorded at higher energies. The absence of IC-catastrophe signatures provides either a lower limit delta>8 to the Doppler factor affecting the radio emission or strong constraints for modelling of the Compton catastrophes in S5 0716+71.Comment: 15 pages, 3 EPS figures, 3 tables, to appear in A&

Applications of evolutionary methods for complex industrial problems

Adaptive Business Intelligence systems combine the methods and techniques that enable prediction, optimisation and adaptation. Adaptive Business Intelligence software solutions powered by Computational Intelligence tools are invaluable for making better predictions and decisions. This paper discusses applicability of Adaptive Business Intelligence software systems for Demand Planning, Advanced Planning and Scheduling, and Supply Chain Network Optimisation, developed by SolveIT Software Pty Ltd.Zbigniew Michalewicz, Maksud Ibrahimov, Arvind Mohais, Sven Schellenberg and Neal Wagnerhttp://www.eurogen2009.polsl.pl/index.htm

Global optimization in supply chain operations

This chapter discusses some optimization issues from a business perspective in the context of the supply chain operations. We note that the term “global optimization” may have different meanings in different communities and we look at it from the business and classical optimization points of view. We present two real-world optimization problems which differ in scope and use them for our discussion on global optimization issues. The differences between these two problems, experimental results, the main challenges they present and the algorithms used are discussed. Here, we claim neither uniqueness nor superiority of the algorithms used, rather the main goal of this chapter is to emphasize the importance of the global optimization concept.Maksud Ibrahimov, Arvind Mohais and Zbigniew Michalewic

Advanced planning in vertically integrated supply chains

During the last few years most production-based businesses have been under enormous pressure to improve their top-line growth and bottom-line savings. As a result, many companies are turning to systems and technologies that can help optimise their supply chain activities and improving short-and long-term demand forecasting. Given the inherent complexities of planning and scheduling in vertically integrated supply chains, many new methods (e.g., ant systems, evolutionary algorithms, fuzzy systems, genetic algorithms, neural networks, rough sets, swarm intelligence, simulated annealing, tabu search-collectively known as "Computational Intelligence" methods) have been introduced into software applications to help manage and and optimise this complexity. In this paper we discuss two realworld applications of advanced planning: one from wine industry and the other-from mining industry. © 2011 Springer-Verlag Berlin Heidelberg.Maksud Ibrahimov, Arvind Mohais, Sven Schellenberg, and Zbigniew Michalewiczhttp://nla.gov.au/anbd.bib-an4802882