876 research outputs found

    Kinematics of the Broad-line Region of 3C 273 from a Ten-year Reverberation Mapping Campaign

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    Despite many decades of study, the kinematics of the broad-line region of 3C~273 are still poorly understood. We report a new, high signal-to-noise, reverberation mapping campaign carried out from November 2008 to March 2018 that allows the determination of time lags between emission lines and the variable continuum with high precision. The time lag of variations in Hβ\beta relative to those of the 5100 Angstrom continuum is 146.812.1+8.3146.8_{-12.1}^{+8.3} days in the rest frame, which agrees very well with the Paschen-α\alpha region measured by the GRAVITY at The Very Large Telescope Interferometer. The time lag of the Hγ\gamma emission line is found to be nearly the same as for Hβ\beta. The lag of the Fe II emission is 322.057.9+55.5322.0_{-57.9}^{+55.5} days, longer by a factor of \sim2 than that of the Balmer lines. The velocity-resolved lag measurements of the Hβ\beta line show a complex structure which can be possibly explained by a rotation-dominated disk with some inflowing radial velocity in the Hβ\beta-emitting region. Taking the virial factor of fBLR=1.3f_{\rm BLR} = 1.3, we derive a BH mass of M=4.10.4+0.3×108MM_{\bullet} = 4.1_{-0.4}^{+0.3} \times 10^8 M_{\odot} and an accretion rate of 9.3LEddc29.3\,L_{\rm Edd}\,c^{-2} from the Hβ\beta line. The decomposition of its HSTHST images yields a host stellar mass of M=1011.3±0.7MM_* = 10^{11.3 \pm 0.7} M_\odot, and a ratio of M/M2.0×103M_{\bullet}/M_*\approx 2.0\times 10^{-3} in agreement with the Magorrian relation. In the near future, it is expected to compare the geometrically-thick BLR discovered by the GRAVITY in 3C 273 with its spatially-resolved torus in order to understand the potential connection between the BLR and the torus.Comment: 17 pages, 12 figures, 6 tables, accepted for publication in The Astrophysical Journa

    Optimiranje podloge za enzimsku proizvodnju L-cisteina s pomoću Pseudomonas sp. Zjwp-14 primjenom metode odzivnih površina

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    Response surface methodology was applied to optimize medium constituents for enzymatic production of L-cysteine from DL-2-amino-Δ^2-thiazoline-4-carboxylic acid (DL-ATC) by a novel Pseudomonas sp. Zjwp-14. With the Plackett-Burman design experiment, glycerol, DL-ATC, yeast extract, and pH were found to be the most powerful factors among the eight tested variables that influence intracellular enzyme activity for biotransformation of DL-ATC to L-cysteine. In order to investigate the quantitative effects for four variables selected from Plackett-Burman design on enzyme activity, a central composite design was subsequently employed for further optimization. The determination coefficient (R^2) was 0.9817, and the results show that the regression models adequately explain the data variation and represent the actual relationships between the parameters and responses. The optimal medium for Pseudomonas sp. Zjwp-14 was composed of (in g/L): glycerol 16.94, DL-ATC 4.59, yeast extract 6.99, NaCl 5.0, peptone 5.0, beef extract 5.0, MgSO4·7H2O 0.4, and pH=7.94. Under the optimal conditions, the maximum intracellular enzyme activity of 918.7 U/mL in theory and 903.6 U/mL in the experiment were obtained, with an increase of 15.6 % compared to the original medium components. In a 5-litre fermentor, cultivation time for Pseudomonas sp. Zjwp-14 was cut down for 6 h and the maximum enzyme activity reached 929.6 U/mL.Primjenom metode odzivnih površina optimirani su sastojci podloge za enzimsku proizvodnju L-cisteina iz DL-amino-Δ^2-tiazolin-4-karboksilne kiseline (DL-ATC) s pomoću Pseudomonas sp. Zjwp-14. Upotrebom Plackett-Burmanova eksperimentalnog dizajna od 8 ispitanih varijabla, koje utječu na aktivnost enzima u stanici i biotransformaciju DL-ATC u L-cistein, odabrani su ovi najvažniji parametri: koncentracija glicerola, DL-ATC i kvaščeva ekstrakta, te pH-vrijednost. Za daljnje optimiranje četiriju odabranih varijabla uporabljen je centralno složeni plan. Koeficijent determinacije (R^2) iznosio je 0,9817, a rezultati pokazuju da je regresijski model prikladan za objašnjenje podataka i da predstavlja stvarni odnos parametara i odziva. Optimalni sastav podloge za uzgoj Pseudomonas sp. Zjwp-14 bio je (u g/L): glicerol 16,94; DL-ATC 4,59; kvaščev ekstrakt 6,99; NaCl 5,0; pepton 5,0; goveđi ekstrakt 5,0; MgSO4·7H2O 0,4 i pH=7,94. U optimalnim eksperimentalnim uvjetima postignuta je maksimalna aktivnost enzima u stanici od 903,6 U/mL (teorijska vrijednost bila je 918,7 U/mL), što čini povećanje od 15,6 % u usporedbi s početnim sastavom podloge. U reaktoru zapremnine 5 litara vrijeme uzgoja soja Pseudomonas sp. Zjwp-14 skraćeno je za 6 sati, a maksimalna aktivnost enzima dosegla je 929,6 U/mL

    The First Mitochondrial Genome of the Living-Fossil Sawfly \u3cem\u3eMacroxyela ferruginea\u3c/em\u3e (Hymenoptera: Xyelidae, Macroxyelinae)

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    The living-fossil sawfly Macroxyela ferruginea (Xyelidae: Macroxyelinae) was one of the oldest species of Hymenoptera. We sequenced the mitochondrial genome, 15,465 bp in size. All 37 typical mitochondrial genes were possessed. There is only one rearrangement of gene order, where trnM and trnQ were shuffled. We also found this order was shared with Xyela sp., which also belongs to family Xyelidae. The 13 protein-coding genes of this sequence and the other 10 species from eight superfamilies in Hymenoptera were all used for phylogenetic analysis by maximum likelihood (ML) analysis and Bayesian inference (BI), with Ascaloptynx appendiculatus from Neuroptera as an outgroup. The topology demonstrated that M. ferruginea was sister to Xyela sp., supporting that they belong to one family Xyelidae

    Thick MgB2 film with (101) oriented micro-crystals

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    Very thick, ~ 40 μ\mum, clean, and highly textured MgB2 film was effectively grown on an Al2O3 substrate. The fabrication technique is by the hybrid physical-chemical vapor deposition (HPCVD) using B2H6 gas and Mg ingot as the sources. The X-ray diffraction (XRD) analysis shows a highly (101)-oriented MgB2 crystal structure without any impurity detected. There is no signal from the substrate in the XRD spectrum, indicating that the film thickness exceeds the X-ray penetration length. Scanning electron microscopy (SEM) reveals that the film is composed of highly-packed MgB2 micro-crystals with a uniform size distribution of about 2 μ\mum in diameter and 0.2 μ\mum in thickness. According to the compositional analysis of energy-dispersive X-ray spectroscopy (EDX), no oxygen, hence no MgO, exists in the textured film, consistent with the XRD result. Also, the transport properties are similar to those of a single crystal, indicating a clean film of good crystallite. The zero field transition temperatures are determined as TC(onset) = 39.2 K and TC(zero) = 38.4 K, giving a sharp transition typical of a clean sample. The residual resistivity ratio (RRR) is determined as 6.4 and the magnetoreisitance (MR) is about 28 % at 40 K under the applied field of 9 T, which are similar to those of a single crystal. The zero temperature upper critical field, HC2(0), is extrapolated as 19 T from the TC(onset) at applied field up to 9 T.Comment: 10 pages, 4 figure

    Epidemiologic characterization of 30 confirmed cases of human infection with avian influenza A(H7N9) virus in Hangzhou, China

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    BACKGROUND: We examined the clinical and epidemiological characteristics of 30 cases of human infection with avian influenza A(H7N9) virus in Hangzhou and investigated their external environments to provide evidence for contact tracing and disease prevention and control. METHODS: The cases confirmed from April 1 through May 1, 2013 were studied. Field epidemiologic surveys were conducted to collect the clinical and epidemiologic data. Case-related and environmental specimens were collected for etiologic detection. RESULTS: Thirty cases of human infection with avian influenza A(H7N9) virus were confirmed in Hangzhou from April 1 through May 1, 2013, including one pregnant woman and three deaths. The median age of the patients was 62 years (range: 38–86 years). Twenty-three of the patients were men (76.67%). The median duration between disease onset and occurrence of respiratory failure and confirmed diagnosis was 5 and 6 days, respectively. Maximum medical observation of 666 close contacts of the patients revealed no irregularity. Of 314 external environmental specimens, the overall positive detection rate of H7N9 nucleic acid was 28.98%. Eight districts of Hangzhou city had positive detections in the external environments, the highest rate being in Yuhang District (78.13%). Statistical analysis of the specimen collection locations indicates a significant difference between the case-linked locations and the non-case locations (χ( 2 ) = 16.563, p < 0.05) in terms of H7N9 viral nucleic acid detection rate. No epidemiologic link has been found among the 30 cases. CONCLUSIONS: Most of the infected were retired individuals aged 60 years or older. Men made the majority. The cases are sporadic at present, with no evidence of human-to-human transmission. Exposures to poultry and live poultry markets may be important sources of infection

    Tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography: association with N categories

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    OBJECTIVE: To determine whether the gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict the presence of regional lymph node metastasis and could determine N categories. MATERIALS AND METHODS: A total of 202 consecutive patients with gastric adenocarcinoma who had undergone gastrectomy 1 week after contrast-enhanced multidetector computed tomography were retrospectively identified. The gross tumor volume was evaluated on multidetector computed tomography images. Univariate and multivariate analyses were performed to determine whether the gross tumor volume could predict regional lymph node metastasis, and the Mann-Whitney U test was performed to compare the gross tumor volume among N categories. Additionally, a receiver operating characteristic analysis was performed to identify the accuracy of the gross tumor volume in differentiating N categories. RESULTS: The gross tumor volume could predict regional lymph node metastasis (

    Increased brain iron in patients with thyroid-associated ophthalmopathy: a whole-brain analysis

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    BackgroundTo investigate the whole-brain iron deposition alternations in patients with thyroid-associated ophthalmopathy (TAO) using quantitative susceptibility mapping (QSM).MethodsForty-eight patients with TAO and 33 healthy controls (HCs) were enrolled. All participants underwent brain magnetic resonance imaging scans and clinical scale assessments. QSM values were calculated and compared between TAO and HCs groups using a voxel-based analysis. A support vector machine (SVM) analysis was performed to evaluate the performance of QSM values in differentiating patients with TAO from HCs.ResultsCompared with HCs, patients with TAO showed significantly increased QSM values in the bilateral caudate nucleus (CN), left thalamus (TH), left cuneus, left precuneus, right insula and right middle frontal gyrus. In TAO group, QSM values in left TH were positively correlated with Hamilton Depression Rating Scale (HDRS) scores (r = 0.414, p = 0.005). The QSM values in right CN were negatively correlated with Montreal Cognitive Assessment (MoCA) scores (r = -0.342, p = 0.021). Besides that, a nearly negative correlation was found between QSM values in left CN and MoCA scores (r = -0.286, p = 0.057). The SVM model showed a good performance in distinguishing patients with TAO from the HCs (area under the curve, 0.958; average accuracy, 90.1%).ConclusionPatients with TAO had significantly increased iron deposition in brain regions corresponding to known visual, emotional and cognitive deficits. QSM values could serve as potential neuroimaging markers of TAO
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