4,367 research outputs found

    Default Spread dan Term Spread sebagai Variabel Proxy Siklus Bisnis pada Model Fama-French

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    This research aims to apply the Fama-French models and test the effect of alternative variable of bond yield spread, default spread (RBBB – RAAA and RAAA – RF), and the term spread (RSUN10-RSUN1), as proxy variables of the business cycle, in IDX stock data during 2005-2010. Four types of asset pricing models tested are Sharpe-Lintner CAPM, Fama-French models, Hwang et al.model, and hybrid model. The results showed that the size effect and value effect has an impact on excess stock returns. Slopes of market beta, SMB, and HML are more sensitive to stock big size and high B / M. Default spreads and term spreads in Hwang et al. model can explain the value effect, and weakly explain the size effect, meanwhile the power of explanation disappeared on Hybrid models. Based on the assessment adjusted R2 and the frequency of rejection of non-zero alpha, is found that the hybrid model is the most suitable model

    Numerical study of 1.1 GeV electron acceleration over a-few-millimeter-long plasma with a tapered density

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    We present two-dimensional particle-in-cell simulations of laser wakefield electron acceleration up to 1.1 GeV over a-few-millimeter-long plasma with the help of density tapering. We observed that, in a uniform plasma, the electron beam reaches the dephasing state not only by the slow phase velocity of the wakefield but also by the relativistic prolonging of the plasma wavelength. Such a dephasing between the wakefield and beam can be mitigated by an upward density taper. By employing a parabolically increasing plasma density, we obtained a significant enhancement of the beam energy from 850 MeV (uniform) to 1.1 GeV (tapered). However, the similar relativistically promoted dephasing was observed again in the environment of tapered density. Over a few millimeters the driving laser pulse was well self-guided without any externally prepared channel. Thus, this parameter regime is suitable for the gas-jet laser wakefield electron acceleration experiments.open6

    Local Hall effect in hybrid ferromagnetic/semiconductor devices

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    We have investigated the magnetoresistance of ferromagnet-semiconductor devices in an InAs two-dimensional electron gas system in which the magnetic field has a sinusoidal profile. The magnetoresistance of our device is large. The longitudinal resistance has an additional contribution which is odd in applied magnetic field. It becomes even negative at low temperature where the transport is ballistic. Based on the numerical analysis, we confirmed that our data can be explained in terms of the local Hall effect due to the profile of negative and positive field regions. This device may be useful for future spintronic applications.Comment: 4 pages with 4 fugures. Accepted for publication in Applied Physics Letter

    Nonvolatile memories using deep traps formed in HfO₂ by Nb ion implantation

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    We report nonvolatile memories (NVMs) based on deep-energy trap levels formed in HfO₂ by metal ion implantation. A comparison of Nb- and Ta-implanted samples shows that suitable charge-trapping centers are formed in Nb-implanted samples, but not in Ta-implanted samples. This is consistent with density-functional theory calculations which predict that only Nb will form deep-energy levels in the bandgap of HfO₂. Photocurrent spectroscopy exhibits characteristics consistent with one of the trap levels predicted in these calculations. Nb-implanted samples showing memory windows in capacitance–voltage (V) curves always exhibit current (I) peaks in I–V curves, indicating that NVM effects result from deep traps in HfO₂. In contrast, Ta-implanted samples show dielectric breakdowns during the I–V sweeps between 5 and 11 V, consistent with the fact that no trap levels are present. For a sample implanted with a fluence of 10¹³Nb cm⁻², the charge losses after 10⁴ s are ∼9.8 and ∼25.5% at room temperature (RT) and 85°C, respectively, and the expected charge loss after 10 years is ∼34% at RT, very promising for commercial NVMs

    Non-Linear Impact of Growth Opportunity and Firm Size on the Capital Structure

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    One of the focuses on capital structure studies is to identify economic forces influencing corporate capital structure. We investigated the non-linear effects of the firm-specific factors to the leverage of the firm of the US-listed firms. In the partial-adjusted model, growth opportunity and the size of the firm had non-linear effects on the leverage of the firm. Growth opportunity showed quadratic effects on leverage with a negative linear term but a positive quadratic term. It meant if the growth opportunity of a firm reached a certain level, fund providers can relatively detect it and subsequently causes a decrease in asymmetric information. This detection of ample growth opportunity will increase the accessibility of external funding. Firm size also exhibits quadratic effects on leverage with a positive linear term but a negative quadratic term. In other words, if the firm size as a proxy of various omitted variables was imminent, the financial market has been applied the diversification discount that will decrease the accessibility of external funding.JEL Classification: G32, D92DOI: https://doi.org/10.26905/jkdp.v22i4.240

    Energy exchange during stimulated Raman scattering of a relativistic laser in a plasma

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    Energy exchange between pump and daughter waves during the stimulated Raman scattering process in a plasma is investigated, including the effect of a damping coefficient of electron-ion collision at different initial three-wave phases. To obey the energy and momentum conservations, the resonance conditions are satisfied at an optimal initial phase difference between the interacting waves. The amplitudes of the interacting waves exhibit behaviors such as a parametric oscillator. The variations in initial three-wave phase difference generate a phase mismatch, which enhances the rate of the amplitude variations of the interacting waves. The relativistic mass effect modifies the dispersion relations of the interacting waves, and consequently the energy exchange during the stimulated Raman scattering is affected. The collisional damping in the plasma is shown to have an important effect on the evolution of the interacting waves.open91

    Nodulation and Growth of a Supernodulating Soybean Mutant SS2-2 Symbiotically Associated with Bradyrhizobium Japonicum

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    Mutan kedelai penghasil nodulsuper menunjukkan kelemahan dalam kontrol autoregulasi pada nodulasi dan perbedaan fenotip dibandingkan dengan tipe liarnya. Studi untuk mengevaluasi karakter pertumbuhan dan nodulasi dari kedelai penghasil nodulsuper dalam asosiasinya dengan Bradyrhizobium japonicum dilakukan dalam penelitian ini. Tiga genotip kedelai, yaitu mutan kedelai penghasil nodulsuper SS2-2, tipe liarnya Sinpaldalkong 2 dan kedelai kontrol Jangyeobkong diinokulasi dengan B. japonicum USDA 110, kemudian ditumbuhkan di rumah kaca dalam kondisi terkontrol. Karakter nodulasi, fiksasi nitrogen (Acetylene Reduction Activity/ARA), pertumbuhan tanaman, dan hasil biji ditentukan untuk mengevaluasi asosiasi simbiotik antara B. japonicum dan kedelai nodulsuper. Kedelai yang diinokulasi dengan B. japonicum menunjukkan peningkatan jumlah dan berat kering nodul serta berat kering total tanaman dibandingkan dengan tanpa inokulasi. Tanaman SS2-2 yang diinokulasi menunjukkan jumlah nodul sekitar 20 kali lipat lebih tinggi daripada tipe liarnya. Inokulasi B. japonicum ternyata juga meningkatkan fiksasi nitrogen seiring dengan perkembangan nodul. Tanaman S2-2 lebih pendek dan menghasilkan fiksasi nitrogen (ARA) lebih tinggi, tetapi spesifik ARA dan hasil biji lebih rendah dibandingkan dengan tipe liarnya. Berdasarkan hasil evaluasi terhadap nodulasi dan pertumbuhannya, interaksi Rhizobium dan kedelai penghasil nodulsuper SS2-2 mempunyai respon asosiasi simbiotik lebih rendah dibandingkan kedelai penghasil nodul normal (kedelai yang tidak mendapat perlakuan mutasi)

    The Eruption from a Sigmoidal Solar Active Region on 2005 May 13

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    This paper presents a multiwavelength study of the M8.0 flare and its associated fast halo CME that originated from a bipolar active region NOAA 10759 on 2005 May 13. The source active region has a conspicuous sigmoid structure at TRACE 171 A channel as well as in the SXI soft X-ray images, and we mainly concern ourselves with the detailed process of the sigmoid eruption as evidenced by the multiwavelength data ranging from Halpha, WL, EUV/UV, radio, and hard X-rays (HXRs). The most important finding is that the flare brightening starts in the core of the active region earlier than that of the rising motion of the flux rope. This timing clearly addresses one of the main issues in the magnetic eruption onset of sigmoid, namely, whether the eruption is initiated by an internal tether-cutting to allow the flux rope to rise upward or a flux rope rises due to a loss of equilibrium to later induce tether cutting below it. Our high time cadence SXI and Halpha data shows that the first scenario is relevant to this eruption. As other major findings, we have the RHESSI HXR images showing a change of the HXR source from a confined footpoint structure to an elongated ribbon-like structure after the flare maximum, which we relate to the sigmoid-to-arcade evolution. Radio dynamic spectrum shows a type II precursor that occurred at the time of expansion of the sigmoid and a drifting pulsating structure in the flare rising phase in HXR. Finally type II and III bursts are seen at the time of maximum HXR emission, simultaneous with the maximum reconnection rate derived from the flare ribbon motion in UV. We interpret these various observed properties with the runaway tether-cutting model proposed by Moore et al. in 2001.Comment: 10 pages, 10 figures, The Astrophysical Journal, accepted July, 200
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