565 research outputs found

    Alternation of the flickering morphology between the high and low state in MV Lyr

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    AIMS: We studied unique data of a nova-like system MV Lyr during transition from the high to low state and vice versa taken by the Kepler space telescope. We were interested in evolution of frequency components found previously by Scaringi et al. in different data also obtained by Kepler. METHODS: We divided the light curve into 10 day segments and investigated the corresponding power density spectra. We searched for individual frequency components by fitting with Lorentzian functions. Additionally, we investigated the variability using averaged shot profiles calculated from the light curve divided into 10 equally spaces subsamples. RESULTS: We found very complex changes of the power density spectra. We focused our study onto three frequency components. Strong activity increase is seen at low frequencies. Contrariwise, the high frequency part of the spectrum strongly decreases in power with specific rise in characteristic frequencies of the individual components. We discuss various scenarios of this phenomenology as reprocessing of X-rays in a receding accretion disc or a radiation from a more active region at the outer disc. Finally, we show that various cataclysmic variables show similar characteristic frequencies in their power density spectra. These are dependent on activity stage, making the situation similar to X-ray binaries.Comment: accepted for publication to A&

    Pengaruh Peluang Pertumbuhan dan Ketidakpastian Lingkungan terhadap Tindakan Manajemen Laba

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    Effect of Growth Opportunities and Environmental Uncertainties To Profit ManagementThe purpose of this study is to investigate the determinant of firm's earning management by food and beverage industry in Indonesian Stock Exchange (IDX) during 2010-2015. The impact growth opportunity and environmental uncertainty may induce greater manager's use discretionary accruals as earning management. Furthermore, this study also examines the effect auditor quality on the relationship between growth opportunity and earning management. Using purposive sampling, the sample of this study consist 8 companies are listed on IDX (48 firms-year). The result indicated that firm's situation under growth opportunity and environmental uncertainty had an impact on the earning management. However, auditor quality proven has an impact on the relationship between growth opportunity and eaning management.DOI: 10.15408/ess.v6i2.357

    Scalable Spin Amplification with a Gain over a Hundred

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    We propose a scalable and practical implementation of spin amplification which does not require individual addressing nor a specially tailored spin network. We have demonstrated a gain of 140 in a solid-state nuclear spin system of which the spin polarization has been increased to 0.12 using dynamic nuclear polarization with photoexcited triplet electron spins. Spin amplification scalable to a higher gain opens the door to the single spin measurement for a readout of quantum computers as well as practical applications of nuclear magnetic resonance (NMR) spectroscopy to infinitesimal samples which have been concealed by thermal noise.Comment: 6 pages, 7 figure

    Swift Observations of MAXI J1659-152: A Compact Binary with a Black Hole Accretor

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    We report on the detection and follow-up high cadence monitoring observations of MAXI J1659-152, a bright Galactic X-ray binary transient with a likely black-hole accretor, by Swift over a 27 day period after its initial outburst detection. MAXI J1659-152 was discovered almost simultaneously by Swift and MAXI on 2010 Sept 25, and was monitored intensively from the early stages of the outburst through the rise to a brightness of ~0.5 Crab by the Swift XRT, UVOT, and BAT. We present temporal and spectral analysis of the Swift observations. The broadband light-curves show variability characteristic of black-hole candidate transients. We present the evolution of thermal and non-thermal components of the 0.5-150 keV combined X-ray spectra during the outburst. MAXI J1659-152 displays accretion state changes typically associated with black-hole binaries, transitioning from its initial detection in the Hard State, to the Steep Power-Law State, followed by a slow evolution towards the Thermal State, signified by an increasingly dominant thermal component associated with the accretion disk, although this state change did not complete before Swift observations ended. We observe an anti-correlation between the increasing temperature and decreasing radius of the inner edge of the accretion disk, suggesting that the inner edge of the accretion disk in-falls towards the black-hole as the disk temperature increases. We observed significant evolution in the absorption column during the initial rise of the outburst, with the absorption almost doubling, suggestive of the presence of an evolving wind from the accretion disk. We detect quasi- periodic oscillations that evolve with the outburst, as well as irregular shaped dips that recur with a period of 2.42\pm0.09 hours, strongly suggesting an orbital period that would make MAXI J1659-152 the shortest period black-hole binary yet known.Comment: Accepted for publication in ApJ. 9 pages, 7 figure

    X-Ray Fluctuations from Locally Unstable Advection-Dominated Disks

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    The response of advection-dominated accretion disks to local disturbances is examined by one-dimensional numerical simulations. It is generally believed that advection-dominated disks are thermally stable. We, however, find that any disurbance added onto accretion flow at large radii does not decay so rapidly that it can move inward with roughly the free-fall velocity. Although disturbances continue to be present, the global disk structure will not be modified largely. This can account for persistent hard X-ray emission with substantial variations observed in active galactic nuclei and stellar black hole candidates during the hard state. Moreover, when the disturbance reaches the innermost parts, an acoustic wave emerges, propagating outward as a shock wave. The resultant light variation is roughly (time) symmetric and is quite reminiscent of the observed X-ray shots of Cygnus X-1.Comment: plain TeX, 11 pages, without figures; to be published in ApJ Lette

    THE RELATIONSHIP OF BRAND COMMUNICATION, BRAND IMAGE, AND BRAND TRUST TO BRAND LOYALTY OF SAMSUNG CELLULAR PHONE PRODUCT

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    Each people have a trust to the product that they use for daily activity, such as a cellular phone which almost all people are using this product for communicating tool to each other. But not just only for communication purpose, each cellular phone is used by the user for entertaining purpose. Talking about cellular phone, Samsung is one of the most cellular phones that famous in Indonesia, we can see this product everywhere, and many people are using Samsung product, starting from the cheapest one to the most expensive prices, and its users from school age to workers level. As a product, Samsung is one of the famous brands which successful to attract its users and any potential user to use the product. The level of people trust to this product is higher than other products. The trust itself is not coming too easy, Samsung has to convince the customers or potential customers of what benefit that they will get by using Samsung product, and also the fixed product reputation will be able to attract customers’ attention. This research aims to find out the relationship of brand communication, brand image, and brand trust that influences brand loyalty. This research itself is using a statistical the modeling structural equations. The sampling method that applied by the researcher is a random sampling to 130 users (students, workers) of Samsung cellular phone (any types, and prices) in Jakarta, Surabaya, and Tangerang City. The results showed that brand communication influences brand image, brand communication influences brand trust, brand image has an effect on brand trust, and brand trust has an influence on brand loyalty of the Samsung customers

    Combined Spectral and Timing Analysis of the Black Hole Candidate MAXI J1659-152 Discovered by MAXI and Swift

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    We report on X-ray spectral and timing results of the new black hole candidate (BHC) MAXI J1659-152 with the orbital period of 2.41 hours (shortest among BHCs) in the 2010 outburst from 65 Rossi X-ray Timing Explorer (RXTE) observations and 8 simultaneous Swift and RXTE observations. According to the definitions of the spectral states in Remillard & McClintock (2006), most of the observations have been classified into the intermediate state. All the X-ray broadband spectra can be modeled by a multi-color disk plus a power-law with an exponential cutoff or a multi-color disk plus a Comptonization component. During the initial phase of the outburst, a high energy cutoff was visible at 30-40 keV. The innermost radius of the disk gradually decreased by a factor of more than 3 from the onset of the outburst and reached a constant value of 35 d_10 cos i^-1/2 km, where d_10 is the distance in units of 10 kpc and ii is the inclination. The type-C quasi-periodic oscillation (QPO) frequency varied from 1.6 Hz to 7.3 Hz in association with a change of the innermost radius, while the innermost radius remained constant during the type-B QPO detections at 1.6-4.1 Hz. Hence, we suggest that the origin of the type-B QPOs is different from that of type-C QPOs, the latter of which would originate from the disk truncation radius. Assuming the constant innermost radius in the latter phase of the outburst as the innermost stable circular orbit, the black hole mass in MAXI J1659-152 is estimated to be 3.6-8.0 M_solar for a distance of 5.3-8.6 kpc and an inclination angle of 60-75 degrees.Comment: 27 pages, 14 figures, accepted for publication in PAS

    H2-decoupling-accelerated H1 spin diffusion in dynamic nuclear polarization with photoexcited triplet electrons

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    In dynamic nuclear polarization (DNP) experiments applied to organic solids for creating nonequilibrium, high H1 spin polarization, an efficient buildup of H1 polarization is attained by partially deuterating the material of interest with an appropriate H1 concentration. In such a dilute H1 spin system, it is shown that the H1 spin diffusion rate and thereby the buildup efficiency of H1 polarization can further be enhanced by continually applying radiofrequency irradiation for deuterium decoupling during the DNP process. As experimentally confirmed in this work, the electron spin polarization of the photoexcited triplet state is mainly transferred only to those H1 spins, which are in the vicinity of the electron spins, and H1 spin diffusion transports the localized H1 polarization over the whole sample volume. The H1 spin diffusion coefficients are estimated from DNP repetition interval dependence of the initial buildup rate of H1 polarization, and the result indicates that the spin diffusion coefficient is enhanced by a factor of 2 compared to that without H2 decoupling.This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in M. Negoro, K. Nakayama, K. Tateishi, A. Kagawa, K. Takeda, and M. Kitagawa, J. Chem. Phys. 133, 154504 (2010) and may be found at https://doi.org/10.1063/1.3493453

    The X-ray CCD camera of the MAXI Experiment on the ISS/JEM

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    MAXI, Monitor of All-sky X-ray Image, is the X-ray observatory on the Japanese experimental module (JEM) Exposed Facility (EF) on the International Space Station (ISS). MAXI is a slit scanning camera which consists of two kinds of X-ray detectors: one is a one-dimensional position-sensitive proportional counter with a total area of ∼5000cm2\sim 5000 cm^2, the Gas Slit Camera (GSC), and the other is an X-ray CCD array with a total area ∼200cm2\sim 200 cm^2, the Solid-state Slit Camera (SSC). The GSC subtends a field of view with an angular dimension of 1∘×180∘^\circ\times 180^\circ while the SSC subtends a field of view with an angular dimension of 1∘^\circ times a little less than 180∘^\circ. In the course of one station orbit, MAXI can scan almost the entire sky with a precision of 1∘^\circ and with an X-ray energy range of 0.5-30 keV. We have developed the engineering model of CCD chips and the analogue electronics for the SSC. The energy resolution of EM CCD for Mn Kα\alpha has a full-width at half maximum of ≃\simeq 182 eV. Readout noise is ≃\simeq 11 e^- rms.Comment: 10 pages, 4 figures Accepted for Nuclear Instruments and Method in Physics Researc
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