1,598 research outputs found

    The inverse problems for computational psychophysiology: opinions and insights [Editorial]

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    Prognostic Value of Metastatic No.8p LNs in Patients with Gastric Cancer

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    Background. To evaluate prognostic value of metastatic No.8p LNs in patients with gastric cancer. Methods. From August 2002 to December 2011, a total of 284 gastric cancer patients who underwent gastrectomy with No.8p LNs dissection were analyzed retrospectively in this study. Patients were divided into two groups according to the status of No.8p LNs. Clinicopathological features were collected to conduct the correlation analysis. Follow-up was carried out up to December 31st, 2014. Overall survival was analyzed. Results. Out of 284 patients, metastatic No.8p LNs were found in 24 (8.5%) patients. Compared with other 260 cases, these patients suffered morphologically larger tumor (P=0.003), node stage (P=0.000), and metastatic stage (P=0.000). The 3-year overall survival rate was 26% in No.8p-positive group and 53% in No.8p-negative group. No significant difference of cumulative survival rates existed between the No.8p-positive group and No.8p-negative stage IV group (26% versus 28%, P=0.923). Patients with other distant metastasis or not in No.8p+ group had similar cumulative survival rates (24% versus 28%, P=0.914). Conclusions. Positive No.8p LNs were a poor but not an independent prognostic factor for patients with GC and should be recognized as distant metastasis

    Impact of combinations of time-delay interferometry channels on stochastic gravitational wave background detection

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    The method of time delay interferometry (TDI) is proposed to cancel the laser noise in space-borne gravitational-wave detectors. Among all different TDI combinations, the most commonly used ones are the orthogonal channels A, E and T, where A and E are signal-sensitive and T is signal-insensitive. Meanwhile, for the detection of stochastic gravitational-wave background, one needs to introduce the overlap reduction function to characterize the correlation between channels. For the calculation of overlap reduction function, it is often convenient to work in the low-frequency approximation, and assuming the equal-arm Michelson channels. However, if one wishes to work on the overlap reduction function of A/E\rm A/E channels, then the low-frequency approximation fails. We derive the exact form of overlap reduction function for A/E\rm A/E channels. Based on the overlap reduction function, we calculate the sensitivity curves of TianQin, TianQin I+II and TianQin + LISA. We conclude that the detection sensitivity calculated with A/E\rm A/E channels is mostly consistent with that obtained from the equal-arm Michelson channels.Comment: 18 pages,10 figure

    Constraints on the cosmological parameters with three-parameter correlation of Gamma-ray bursts

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    As one of the most energetic and brightest events, gamma-ray bursts (GRBs) can be treated as a promising probe of the high-redshift universe. Similar to type Ia supernovae (SNe Ia), GRBs with same physical origin could be treated as standard candles. We select GRB samples with the same physical origin, which are divided into two groups. One group is consisted of 31 GRBs with a plateau phase feature of a constant luminosity followed by a decay index of about -2 in the X-ray afterglow light curves, and the other has 50 GRBs with a shallow decay phase in the optical light curves. For the selected GRB samples, we confirm that there is a tight correlation between the plateau luminosity L0L_0, the end time of plateau tbt_b and the isotropic energy release Eγ,isoE_{\gamma,iso}. We also find that the L0−tb−Eγ,isoL_0-t_b-E_{\gamma,iso} correlation is insensitive to the cosmological parameters and no valid limitations on the cosmological parameters can be obtained using this correlation. We explore a new three-parameter correlation L0L_0, tbt_b, and the spectral peak energy in the rest frame Ep,iE_{p,i} (L0−tb−Ep,iL_0-t_b-E_{p,i}), and find that this correlation can be used as a standard candle to constrain the cosmological parameters. By employing the optical sample only, we find the constraints of Ωm=0.697−0.278+0.402(1σ)\Omega_m = 0.697_{-0.278}^{+0.402}(1\sigma) for a flat Λ\LambdaCDM model. For the non-flat Λ\LambdaCDM model, the best-fitting results are Ωm=0.713−0.278+0.346\Omega_m = 0.713_{-0.278}^{+0.346}, ΩΛ=0.981−0.580+0.379(1σ)\Omega_{\Lambda} = 0.981_{-0.580}^{+0.379}(1\sigma). For the combination of the X-ray and optical smaples, we find Ωm=0.313−0.125+0.179(1σ)\Omega_m = 0.313_{-0.125}^{+0.179}(1\sigma) for a flat Λ\LambdaCDM model, and Ωm=0.344−0.112+0.176\Omega_m = 0.344_{-0.112}^{+0.176}, ΩΛ=0.770−0.416+0.366(1σ)\Omega_{\Lambda} = 0.770_{-0.416}^{+0.366}(1\sigma) for a non-flat Λ\LambdaCDM model.Comment: Accepted for publication in The Astrophysical Journal, 13 pages, 9 figures and 2 table

    Direct observation of the formation and stabilization of metallic nanoparticles on carbon supports

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    Direct formation of ultra-small nanoparticles on carbon supports by rapid high temperature synthesis method offers new opportunities for scalable nanomanufacturing and the synthesis of stable multi-elemental nanoparticles. However, the underlying mechanisms affecting the dispersion and stability of nanoparticles on the supports during high temperature processing remain enigmatic. In this work, we report the observation of metallic nanoparticles formation and stabilization on carbon supports through in situ Joule heating method. We find that the formation of metallic nanoparticles is associated with the simultaneous phase transition of amorphous carbon to a highly defective turbostratic graphite (T-graphite). Molecular dynamic (MD) simulations suggest that the defective T-graphite provide numerous nucleation sites for the nanoparticles to form. Furthermore, the nanoparticles partially intercalate and take root on edge planes, leading to high binding energy on support. This interaction between nanoparticles and T-graphite substrate strengthens the anchoring and provides excellent thermal stability to the nanoparticles. These findings provide mechanistic understanding of rapid high temperature synthesis of metal nanoparticles on carbon supports and the origin of their stability

    Measuring the Hubble Constant Using Strongly Lensed Gravitational Wave Signals

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    The measurement of the Hubble constant H0H_0 plays an important role in the study of cosmology. In this letter, we propose a new method to constrain the Hubble constant using the strongly lensed gravitational wave (GW) signals. By reparameterizing the waveform, we find that the lensed waveform is sensitive to the H0H_0. Assuming the scenario that no electromagnetic counterpart of the GW source can be identified, our method can still give meaningful constraints on the H0H_0 with the information of the lens redshift. We then apply Fisher information matrix and Markov Chain Monte Carlo to evaluate the potential of this method. For the space-based GW detector, TianQin, the H0H_0 can be constrained within a relative error of ∼\sim 0.3-2\%, using a single strongly lensed GW event. Precision varies according to different levels of electromagnetic information.Comment: 8 pages, 4 figure

    Radio Plateaus in Gamma-Ray Burst Afterglows and Their Application in Cosmology

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    The plateau phase in the radio afterglows has been observed in very few gamma-ray bursts (GRBs), and 27 radio light curves with plateau phase were acquired from the published literature in this article. We obtain the related parameters of the radio plateau, such as temporal indexes during the plateau phase (α1\alpha_1 and α2\alpha_2), break time (\Tbz) and the corresponding radio flux (FbF_{\rm b}). The two parameter Dainotti relation between the break time of the plateau and the corresponding break luminosity (\Lbz) in radio band is \Lbz \propto \Tbz^{-1.20\pm0.24}. Including the isotropic energy \Eiso and the peak energy \Epi, the three parameter correlations for the radio plateaus are written as \Lbz \propto \Tbz^{-1.01 \pm 0.24} \Eiso^{0.18 \pm 0.09} and \Lbz \propto \Tbz^{-1.18 \pm 0.27} \Epi^{0.05 \pm 0.28}, respectively. The correlations are less consistent with that of X-ray and optical plateaus, implying that radio plateaus may have a different physical mechanism. The typical frequencies crossing the observational band may be a reasonable hypothesis that causes the breaks of the radio afterglows. We calibrate GRBs empirical luminosity correlations as standard candle for constraining cosmological parameters, and find that our samples can constrain the flat Λ\LambdaCDM model well, while are not sensitive to non-flat Λ{\Lambda}CDM model. By combining GRBs with other probes, such as SN and CMB, the constraints on cosmological parameters are \om = 0.297\pm0.006 for the flat Λ{\Lambda}CDM model and \om = 0.283\pm0.008, \oL = 0.711\pm0.006 for the non-flat Λ{\Lambda}CDM model, respectively.Comment: 16 pages, 6 figures and 6 tables, accepted for publication in Ap

    Effects of temperature and wavelength choice on in-situ dissolution test of Cimetidine tablets

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    AbstractThe effects of temperature and wavelength choice on in-situ dissolution test instrument of Cimetidine were studied. Absorbance (A)<1.0 is required when using a fiber-optic dissolution test system. The detection wavelength of λmax (218nm) was replaced by 244nm to carry out this test. The absorbance of Cimetidine solution at different temperature showed an obvious change. Calibration of Cimetidine solution should be tested at the same temperature (37°C) with the test solution. A suitable wavelength with smaller tangent slope could be chosen for in-situ dissolution test of Cimetidine tablets
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