931 research outputs found

    Multi-wavelength Stellar Polarimetry of the Filamentary Cloud IC5146: I. Dust Properties

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    We present optical and near-infrared stellar polarization observations toward the dark filamentary clouds associated with IC5146. The data allow us to investigate the dust properties (this paper) and the magnetic field structure (Paper II). A total of 2022 background stars were detected in RcR_{c}-, ii'-, HH-, and/or KK-bands to AV25A_V \lesssim 25 mag. The ratio of the polarization percentage at different wavelengths provides an estimate of λmax\lambda_{max}, the wavelength of peak polarization, which is an indicator of the small-size cutoff of the grain size distribution. The grain size distribution seems to significantly change at AVA_V \sim 3 mag, where both the average and dispersion of PRc/PHP_{R_c}/P_{H} decrease. In addition, we found λmax\lambda_{max} \sim 0.6-0.9 μ\mum for AV>2.5A_V>2.5 mag, which is larger than the \sim 0.55 μ\mum in the general ISM, suggesting that grain growth has already started in low AVA_V regions. Our data also reveal that polarization efficiency (PE Pλ/AV\equiv P_{\lambda}/A_V) decreases with AVA_V as a power-law in RcR_c-, ii'-, and KK-bands with indices of -0.71±\pm0.10, -1.23±\pm0.10 and -0.53±\pm0.09. However, HH-band data show a power index change; the PE varies with AVA_V steeply (index of -0.95±\pm0.30) when AV<2.88±0.67A_V < 2.88\pm0.67 mag but softly (index of -0.25±\pm0.06) for greater AVA_V values. The soft decay of PE in high AVA_V regions is consistent with the Radiative Aligned Torque model, suggesting that our data trace the magnetic field to AV20A_V \sim 20 mag. Furthermore, the breakpoint found in HH-band is similar to the AVA_V where we found the PRc/PHP_{R_c}/P_{H} dispersion significantly decreased. Therefore, the flat PE-AVA_V in high AVA_V regions implies that the power index changes result from additional grain growth.Comment: 31 pages, 17 figures, and 3 tables; accepted for publication in Ap

    Seismic evidence for a mantle plume beneath the Cape Verde hotspot

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    <div><p>P- and S-wave tomography of the upper mantle beneath the Cape Verde hotspot is determined using arrival-time data measured precisely from three-component seismograms of 106 distant earthquakes recorded by a local seismic network. Our results show a prominent low-velocity anomaly imaged as a continuous column <100 km wide from the uppermost mantle down to about 500 km beneath Cape Verde, especially below the Fogo active volcano, which erupted in 1995. The low-velocity anomaly may reflect a hot mantle plume feeding the Cape Verde hotspot.</p></div

    A Temporal Credential-Based Mutual Authentication with Multiple-Password Scheme for Wireless Sensor Networks

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    <div><p>Wireless sensor networks (WSNs), which consist of a large number of sensor nodes, have become among the most important technologies in numerous fields, such as environmental monitoring, military surveillance, control systems in nuclear reactors, vehicle safety systems, and medical monitoring. The most serious drawback for the widespread application of WSNs is the lack of security. Given the resource limitation of WSNs, traditional security schemes are unsuitable. Approaches toward withstanding related attacks with small overhead have thus recently been studied by many researchers. Numerous studies have focused on the authentication scheme for WSNs, but most of these works cannot achieve the security performance and overhead perfectly. Nam et al. proposed a two-factor authentication scheme with lightweight sensor computation for WSNs. In this paper, we review this scheme, emphasize its drawbacks, and propose a temporal credential-based mutual authentication with a multiple-password scheme for WSNs. Our scheme uses multiple passwords to achieve three-factor security performance and generate a session key between user and sensor nodes. The security analysis phase shows that our scheme can withstand related attacks, including a lost password threat, and the comparison phase shows that our scheme involves a relatively small overhead. In the comparison of the overhead phase, the result indicates that more than 95% of the overhead is composed of communication and not computation overhead. Therefore, the result motivates us to pay further attention to communication overhead than computation overhead in future research.</p></div

    Immunohistochemical localization for Bax.

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    <p>There was few specific expression of Bax in normal tissue (B). Protein expression of Bax was significantly increased in the epithelial cell, intestine glands and in the inflammatory cells infiltrating in the tissue of model animals (C). Treatment of SASP (150 mg/kg), Bax protein expression was obviously reduced (D). Administration with IG (80 mg/kg, E; 160 mg/kg, F; 240 mg/kg, G), protein expression of Bax was effectively inhibited in both mucosa and submucosa in dose-dependent manner (A). Specific expression of Bax was very weak in the colonic tissue of high-dose group (<b>G</b>). Original magnification 400×.</p

    Additional file 1: of Audio bandwidth extension using ensemble of recurrent neural networks

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    Demonstration for subjective listening tests. (PPT 10166 kb

    Effect of iridoid glycosides on the mRNA expressions of TNF-α, IL-8, TGF-β1 and COX-2 in DSS-induced colitis.

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    <p>Rats were administered with IG (80, 160, 240 mg/kg/day p.o.) for 14 days. SASP (150 mg/kg/day p.o.) was used as a positive control. The mRNA expressions of (A) TNF-α, (B) IL-8, (C) TGF-β1 and (D) COX-2 were determined using real-time quantitative PCR. The data are expressed as the mean ± standard deviation (Mean ± SD). ΔΔ p<0.01 vs normal group; * p<0.05, ** p<0.01 vs DSS group; ★ p<0.05, ★★ p<0.01 vs SASP group.</p

    Effect of iridoid glycosides on intestinal epithelial cells apoptosis.

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    <p>Apoptotic cells in the colon tissues were detected using TUNEL assay. Cells with nuclei that stained dark brown were considered to be TUNEL-positive. (A) Apoptosis index (%); (B) Normal group, (C) DSS Model group; (D) SASP group; (E) IG 80 mg/kg, (F) IG 160 mg/kg and (G) IG 240 mg/kg (original magnification ×400). Apoptosis index indicated that the percentage of TUNEL-positive cells significantly decreased in a dose-dependent manner after treatment with IG compared with the DSS Model group. Data were expressed as mean ±SD (each group, n = 10). ΔΔ p<0.01 versus normal group; * p<0.05, ** p<0.01 versus DSS group; ★ p<0.05 versus SASP group.</p

    Comparison of storage overhead.

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    <p>Comparison of storage overhead.</p

    Effect of iridoid glycosides on the mRNA expressions of Fas/FasL, Bcl-2 and Caspase-3 in DSS-induced colitis.

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    <p>Rats were administered with IG (80, 160, 240 mg/kg/day p.o.) for 14 days. SASP (150 mg/kg/day p.o.) was used as a positive control. The mRNA expressions of (A) Fas/FasL, (B) Bcl-2 and (C) Caspase-3 were determined using real time quantitative PCR. The data are expressed as the mean ± standard deviation (Mean ± SD). ΔΔ p<0.01 vs normal group; * p<0.05, ** p<0.01 vs DSS group; ★ p<0.05, ★★ p<0.01 vs SASP group.</p

    Sequences of the amplification primers used in the real-time RT-PCR.

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    <p>Sequences of the amplification primers used in the real-time RT-PCR.</p
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