4,115 research outputs found

    On the NLO Power Correction to Photon-Pion Transition Form Factor

    Full text link
    We propose a perturbative evaluation for the next-to-leading-order (NLO) O(1/Q4)O(1/Q^4) power correction to the photon-pion transition form factor. The effects of the NLO power correction are analyzed.Comment: 4 pages, 3 figures, Revtex, revised versio

    High resolution Compton scattering as a Probe of the Fermi surface in the Iron-based superconductor LaO1xFxFeAsLaO_{1-x}F_xFeAs

    Full text link
    We have carried out first principles all-electron calculations of the (001)-projected 2D electron momentum density and the directional Compton profiles along the [100], [001] and [110] directions in the Fe-based superconductor LaOFeAs within the framework of the local density approximation. We identify Fermi surface features in the 2D electron momentum density and the directional Compton profiles, and discuss issues related to the observation of these features via Compton scattering experiments.Comment: 4 pages, 3 figure

    Establishing and Externally Validating a Hemoglobin, Albumin, Lymphocyte, and Platelet (HALP) Score-Based Nomogram for Predicting Early Recurrence in BCLC Stage 0/A Hepatocellular Carcinoma Patients After Radical Liver Resection: A Multi-Center Study

    Get PDF
    Xulin Liu,1,&ast; Zhancheng Qiu,2,&ast; Elijah Ndhlovu,1,&ast; Yunyan Wan,3 Huapeng Sun,4 Shuai Wang,5 Yugang Cao,6 Peng Zhu1 1Department of Hepatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People’s Republic of China; 2Division of Liver Surgery, Department of General Surgery, West China Hospital, Sichuan University, Chengdu, Sichuan Province, People’s Republic of China; 3Department of Hepatobiliary Pancreatic Surgery, Taihe Hospital, Shiyan City, Hubei Province, People’s Republic of China; 4Department of General Surgery, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, People’s Republic of China; 5Department of Hepatobiliary Surgery, Jingzhou Central Hospital, Jingzhou, People’s Republic of China; 6Department of Hepatobiliary and Pancreatic Surgery, Huangshi Central Hospital of Edong Healthcare Group, Huangshi, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Peng Zhu, Department of Hepatic Surgery, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People’s Republic of China, Tel +86 13907170712, Email [email protected]: Early recurrence (ER) is associated with poor prognosis in hepatocellular carcinoma (HCC). In this study, we developed and externally validated a nomogram based on the hemoglobin, albumin, lymphocytes, and platelets (HALP) score to predict ER for patients with BCLC stage 0/A HCC who underwent radical liver resection.Patients and Methods: A total of 808 BCLC stage 0/A HCC patients from six hospitals were included in this study, and they were assigned to a training cohort (n = 500) and an external validation cohort (n = 308). We used univariate and multivariate Cox regression analysis to identify the independent risk factors for disease-free survival (DFS). We also established and externally validated a nomogram based on these risk predictors. The nomogram was evaluated using the area under the receiver operating characteristic curve (AUC), the concordance index (C-index), the calibration curve, decision curve analysis (DCA), and Kaplan‒Meier analysis.Results: Multivariate COX regression showed that HBV DNA ≥ 10,000 IU/mL (P < 0.001), HALP score ≤ 38.20 (P < 0.001), tumor size (P = 0.003), clinically significant portal hypertension (P = 0.001), Edmondson-Steiner grade (III–IV) (P = 0.007), satellite nodules (P < 0.001), and MVI (P = 0.001) were independent risk factors for post-operative tumor recurrence. The AUC of our nomogram for predicting the 2-year and 5-year DFS was 0.756 and 0.750, respectively, in the training cohort and 0.764 and 0.705, respectively, in the external validation cohort. We divided the patients into low-, intermediate- and high-risk groups according to the risk score calculated by the nomogram. There were statistically significant differences in the DFS and overall survival (OS) among the three groups of patients (P < 0.001).Conclusion: We developed and externally validated a new nomogram, which is accurate and can predict ER in BCLC stage 0/A HCC patients after curative liver resection.Keywords: early recurrence, hepatocellular carcinoma, HALP score, nomogram, Barcelona Clinic of Liver Cancer staging system, disease-free surviva

    Extraordinary Late-Time Infrared Emission of Type IIn Supernovae

    Full text link
    Near-Infrared (NIR) observations are presented for five Type IIn supernovae (SN 1995N, SN 1997ab, SN 1998S, SN 1999Z, and SN 1999el) that exhibit strong infrared excesses at late times (t >= 100 d). H- and K-band emission from these objects is dominated by a continuum that rises toward longer wavelengths. The data are interpreted as thermal emission from dust, probably situated in a pre-existing circumstellar nebula. The IR luminosities implied by single temperature blackbody fits are quite large,> 10^(41 - 42) erg s^-1, and the emission evolves slowly, lasting for years after maximum light. For SN 1995N, the integrated energy release via IR dust emission was 0.5 -- 1 * 10^50 erg. A number of dust heating scenarios are considered, the most likely being an infrared echo poweredby X-ray and UV emissions from the shock interaction with a dense circumstellar medium.Comment: 14 Pages, 3 Figures, Accecpted for publication in The Astrophysical Journa

    Fate and transport of chromium in industrial sites: dynamic simulation on soil profile

    Get PDF
    Direct discharge of chromium-containing waste water and improper disposal of waste residues in industrial sites may lead to the vertical migration of metals into aquifers, posing serious threat to soil-groundwater system. The heterogeneity in soil profile further aggravates the complexity and unpredictability of this transport process. However, topsoil was the main focus of most studies. Herein, the vertical transport and transformation of Cr in soils at different depths in three industrial sites (i.e., Shijiazhuang, Zhuzhou, and Guangzhou) were investigated to delineate Cr transport and retention characteristics under complex conditions. Regional and vertical differences in soil properties led to the specificity in Cr migration behaviors among these three sites. Correlation analysis showed that soil pH (r = −0.909, p r = 0.949, p 3 within 20 years. Heavier rainfall condition exacerbated the contamination due to an increased pollutant flux and enhanced convection. Specially, Cr was fixed in the topsoil of Zhuzhou site with the formation of PbCrO4 and presented least vertical migration risk. The conclusions above can provide scientific theoretical guidance for heavy metal pollution prevention and control in industrial contaminated regions.Environmental Biolog

    Pressure-induced unconventional quantum phase transition with fractionalization in the coupled ladder antiferromagnet C9H18N2CuBr4

    Full text link
    We present a comprehensive study of the effect of hydrostatic pressure on the magnetic structure and spin dynamics in the spin-1/2 coupled ladder compound C9_9H18_{18}N2_2CuBr4_4. The applied pressure is demonstrated as a parameter to effectively tune the exchange interactions in the spin Hamiltonian without inducing a structural transition. The single-crystal heat capacity and neutron diffraction measurements reveal that the Neˊ\rm \acute{e}el ordered state breaks down at and above a critical pressure PcP_{\rm c}\sim1.0 GPa through a continuous quantum phase transition. The thorough analysis of the critical exponents indicates that such transition with a large anomalous exponent η\eta into a quantum-disordered state cannot be described by the classic Landau's paradigm. Using inelastic neutron scattering and quantum Monte Carlo methods, the high-pressure regime is proposed as a Z2Z_2 quantum spin liquid phase in terms of characteristic fully gapped vison-like and fractionalized excitations in distinct scattering channels.Comment: 6 pages and 4 figures in the main text. The Supplementary Material is available upon the reques

    Strong competition between orbital ordering and itinerancy in a frustrated spinel vanadate

    Get PDF
    The crossover from localized to itinerant electron regimes in the geometrically frustrated spinel system Mn1-x CoxV2O4 is explored by neutron-scattering measurements, first-principles calculations, and spin models. At low Co doping, the orbital ordering (OO) of the localized V3+ spins suppresses magnetic frustration by triggering a tetragonal distortion. At high Co doping levels, however, electronic itinerancy melts the OO and lessens the structural and magnetic anisotropies, thus increasing the amount of geometric frustration for the V-site pyrochlore lattice. Contrary to the predicted paramagentism induced by chemical pressure, the measured noncollinear spin states in the Co-rich region of the phase diagram provide a unique platform where localized spins and electronic itinerancy compete in a geometrically frustrated spinel.open1
    corecore