6,923 research outputs found

    Phase-reference VLBI Observations of the Compact Steep-Spectrum Source 3C 138

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    We investigate a phase-reference VLBI observation that was conducted at 15.4 GHz by fast switching VLBA antennas between the compact steep-spectrum radio source 3C 138 and the quasar PKS 0528+134 which are about 4∘^\circ away on the sky. By comparing the phase-reference mapping with the conventional hybrid mapping, we demonstrate the feasibility of high precision astrometric measurements for sources separated by 4∘^\circ. VLBI phase-reference mapping preserves the relative phase information, and thus provides an accurate relative position between 3C 138 and PKS 0528+134 of Δα=−9m46s.531000±0s.000003\Delta\alpha=-9^m46^s.531000\pm0^s.000003 and Δδ=3∘6′26′′.90311±0′′.00007\Delta\delta=3^\circ6^\prime26^{\prime\prime}.90311\pm0^{\prime\prime}.00007 (J2000.0) in right ascension and declination, respectively. This gives an improved position of the nucleus (component A) of 3C 138 in J2000.0 to be RA=05h21m9s.88574805^h 21^m 9^s.885748 and Dec=16∘38′22′′.0526116^\circ 38' 22''.05261 under the assumption that the position of calibrator PKS 0528+134 is correct. We further made a hybrid map by performing several iterations of CLEAN and self-calibration on the phase-referenced data with the phase-reference map as an input model for the first phase self-calibration. Compared with the hybrid map from the limited visibility data directly obtained from fringe fitting 3C 138 data, this map has a similar dynamic range, but a higher angular resolution. Therefore, phase-reference technique is not only a means of phase connection, but also a means of increasing phase coherence time allowing self-calibration technique to be applied to much weaker sources.Comment: 9 pages plus 2 figures, accepted by PASJ (Vol.58 No.6

    Acute cholecystitis associated with infection of Enterobacteriaceae from gut microbiota

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    AbstractAcute cholecystitis (AC) is one of the most common surgical diseases. Bacterial infection accounts for 50% to 85% of the disease's onset. Since there is a close relationship between the biliary system and the gut, the aims of this study were to characterize and determine the influence of gut microbiota on AC, to detect the pathogenic microorganism in the biliary system, and to explore the relationship between the gut and bile microbiota of patients with AC. A total of 185 713 high-quality sequence reads were generated from the faecal samples of 15 patients and 13 healthy controls by 16S rRNA gene pyrosequencing. Patients' samples were significantly enriched in Akkermansia, Enterobacter and Escherichia/Shigella group. The healthy controls, however, showed significant enrichment of Clostridiales, Coprococcus, Coprobacillaceae, Paraprevotella, Turicibacter and TM7-3 in their faecal samples. Escherichia coli was the main biliary pathogenic microorganism, among others such as Klebsiella spp., Clostridium perfringens, Citrobacter freundii and Enterobacter cloacae in the bile of the patients. Additionally, the amount of bile endotoxin significantly correlated with the number of Enterobacteriaceae, especially E. coli. Our data indicate that Enterobacteriaceae might play essential role in the pathogenesis and/or progress of AC. This was verified in an in vivo model using a pathogenic E. coli isolated from one of the patients in guinea pigs and observed marked gallbladder inflammation and morphologic changes. This study thus provides insight which could be useful for the prevention, diagnosis and treatment of AC and related diseases by controlling the growth of Enterobacteriaceae to alleviate the infection

    Derivation and Validation of Risk Scores to Predict Cerebrovascular Mortality Among Incident Peritoneal Dialysis Patients

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    Background/Aims: Cerebrovascular disease (CeVD) is one of the leading causes of death in patients initialising peritoneal dialysis (PD). Currently there is no risk score to predict the future risk of CeVD on entry into PD. This study aimed to derive and validate a risk prediction model for CeVD mortality in 2 years after the initialisation of PD. Methods: All patients registered with the Henan Peritoneal Dialysis Registry (HPDR) between 2007 and 2014 were included. Multivariable logistic regression modelling was applied to derive the risk score. All accessible clinical measurements were screened as potential predictors. Internal validation through bootstrapping was applied to test the model performance. Results: The absolute risk of CeVD mortality was 2.9%. Systolic and diastolic blood pressure, total cholesterol, phosphate, and sodium concentrations were the strongest predictors of CeVD mortality in the final risk score. Good model discrimination with C statistics above 0.70 and calibration of agreed observed and predicted risks were identified in the model. Conclusion: The new risk score, developed and validated using clinical measurements that are accessible on entry into PD, could be used clinically to screen for patients at high risk of CeVD mortality. Such patients might benefit from therapies reducing the incidence of CeVD related events

    Fetal Familial Cerebral Cavernous Malformation With a Novel Heterozygous KRIT1 Pathogenic Variant

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    OBJECTIVES: To identify fetal familial cerebral cavernous malformation (CCMs) and a novel mutation. METHODS: A 37-year-old pregnant woman (G4P0) presented right-handed numbness since two weeks at 31 weeks of gestation. Evaluation with brain magnetic resonance imaging (MRI) revealed multiple CCMs. As a result, fetal MRI, fetal Whole Exome Sequencing (WES), and maternal Sanger sequencing were performed. RESULTS: The mother's brain MRI demonstrated numerous CCMs involving the brain stem, cerebral hemispheres, and cerebellum. Fetal MRI showed a CCM located in the left frontal lobe in SWI. The neuroimaging characteristics of the mother and the fetus suggested that their CCMs may be familial. Genetic analysis revealed a novel mutation in KRIT1 (c.1A>G, p.0?), also called CCM1, in the mother and the baby. The mother delivered a daughter at 32 weeks of gestation with an Apgar score of 10 by cesarean section. DISCUSSION: This mutation of the initial codon in the KRIT1 gene leads to a phenotype with an early-onset. To our knowledge, this is the first-ever reported case of fetal familial CCM and this novel mutation. Brain MRI has excellent sensitivity and specificity, providing the best option for detecting CCMs, even in utero, primarily when SWI is used

    Dependence of quantum correlations of twin beams on pump finesse of optical parametric oscillator

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    The dependence of quantum correlation of twin beams on the pump finesse of an optical parametric oscillator is studied with a semi-classical analysis. It is found that the phase-sum correlation of the output signal and idler beams from an optical parametric oscillator operating above threshold depends on the finesse of the pump field when the spurious pump phase noise generated inside the optical cavity and the excess noise of the input pump field are involved in the Langevin equations. The theoretical calculations can explain the previously experimental results, quantitatively.Comment: 27 pages, 8 figure

    HPSAP: A High-Performance and Synthesizable Asynchronous Pipeline with Quasi-2phase Conversion Method

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    \ua9 2013 IEEE.This paper presents a high-performance and synthesizable asynchronous pipeline (HPSAP). First, a 4-phase pipeline controlled by the relative-timing (RT) controller is designed. The controller is small (7 gates) and its handshake protocol is highly concurrent, resulting in fewer component delays in cycle time. However, the RT pipeline\u27s throughput is limited by the inherent reset phase in the 4-phase protocol. Thus, the variant HPSAP pipeline is proposed with the quasi-2phase conversion method. Unlike other existing solutions which aimed at reducing the reset time of the 4-phase protocol, this method imitates the behavior of the 2-phase pipeline and re-activates the reset edge by two steps: 1) replacing all delay-matched units with the maximum delay; 2) adding a small pulse generator on each RT controller. The post-layout HSPICE simulation of a 4-bit 10-stage HPSAP first-in-first-out (FIFO) pipeline indicated a throughput of 5.382 giga data item per second (GDI/s) under SMIC 55nm CMOS technology, which was 77.5% and 14.65% higher than the Click pipeline and Mousetrap pipeline. In the pipeline with processing, a 32 7 32 bits multiplier was built, and the maximum working frequency of the HPSAP multiplier was faster than Mousetrap and the synchronous counterparts

    A Microcalorimetric Method for Studying the Biological Effects of Mg2+ Ion on Recombinant Escherichia coli

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    Power-time curves of growing recombinant Escherichia coli B1 cell suspensions, treated with different concentrations of Mg2+, were recorded by microcalorimeter. The extent of the stimulatory effect of Mg2+ on the growth of recombinant E. coli B1 was compared by reference to the changes in the values of the growth rate coefficient of bacteria (k), the time of reaching the maximum effect in the log phase (tD), the time of maintaining the maximum effect in the stationary period (tS), and the maximum thermal power during the entire bacterial growth (Pm) at different Mg2+ doses and the optimal Mg2+ dose was calculated. The experimental results revealed that when Mg2+ mass concentration reached γ = 2.2 mg mL-1, the stimulatory effect is the greatest. With more Mg2+ (γ > 2.2 mg mL-1) added, the promotive effect would decrease drastically
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