A way to measure the water quality of the LHAASO-WCDA with cosmic muon signals

The Large High Altitude Air Shower Observatory (LHAASO) is to be built at Daocheng, Sichuan Province, China. As one of the major components of the LHAASO project, a Water Cherenkov Detector Array (WCDA), with an area of 78,000~$\rm m^{2}$, contains 350,000~tons of purified water. The water transparency and its stability are critical for successful long-term operation of this project. To gain full knowledge of the water Cherenkov technique and investigate the engineering issues, a 9-cell detector array has been built at the Yangbajing site, Tibet, China. With the help of the distribution of single cosmic muon signals, the monitoring and measurement of water transparency are studied. The results show that a precision of several percent can be obtained for the attenuation length measurement, which satisfies the requirements of the experiment. In the near future, this method could be applied to the LHAASO-WCDA project

Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. V. A New Size-Luminosity Scaling Relation for the Broad-Line Region

This paper reports results of the third-year campaign of monitoring super-Eddington accreting massive black holes (SEAMBHs) in active galactic nuclei (AGNs) between 2014-2015. Ten new targets were selected from quasar sample of Sloan Digital Sky Survey (SDSS), which are generally more luminous than the SEAMBH candidates in last two years. H$\beta$ lags ($\tau_{_{\rm H\beta}}$) in five of the 10 quasars have been successfully measured in this monitoring season. We find that the lags are generally shorter, by large factors, than those of objects with same optical luminosity, in light of the well-known $R_{_{\rm H\beta}}-L_{5100}$ relation. The five quasars have dimensionless accretion rates of $\dot{\mathscr{M}}=10-10^3$. Combining measurements of the previous SEAMBHs, we find that the reduction of H$\beta$ lags tightly depends on accretion rates, $\tau_{_{\rm H\beta}}/\tau_{_{R-L}}\propto\dot{\mathscr{M}}^{-0.42}$, where $\tau_{_{R-L}}$ is the H$\beta$ lag from the normal $R_{_{\rm H\beta}}-L_{5100}$ relation. Fitting 63 mapped AGNs, we present a new scaling relation for the broad-line region: $R_{_{\rm H\beta}}=\alpha_1\ell_{44}^{\beta_1}\,\min\left[1,\left(\dot{\mathscr{M}}/\dot{\mathscr{M}}_c\right)^{-\gamma_1}\right]$, where $\ell_{44}=L_{5100}/10^{44}\,\rm erg~s^{-1}$ is 5100 \AA\ continuum luminosity, and coefficients of $\alpha_1=(29.6_{-2.8}^{+2.7})$ lt-d, $\beta_1=0.56_{-0.03}^{+0.03}$, $\gamma_1=0.52_{-0.16}^{+0.33}$ and $\dot{\mathscr{M}}_c=11.19_{-6.22}^{+2.29}$. This relation is applicable to AGNs over a wide range of accretion rates, from $10^{-3}$ to $10^3$. Implications of this new relation are briefly discussed.Comment: 15 pages, 9 figures, 5 table, accepted for publication in The Astrophysical Journa

Implications of new-onset atrial fibrillation on in-hospital and long-term prognosis of patients with acute myocardial infarction:A report from the CBD bank study

BACKGROUND: An increase in the incidence of atrial fibrillation (AF) during the acute phase of myocardial infarction (AMI) has been observed. But it is still unclear whether the implications of new-onset AF on in-hospital and long-term prognosis are of similar magnitude. METHODS: Using data from the CBD Bank study, 3,824 consecutive AMI patients, without prior AF, were analyzed. During the index hospitalization, all patients were monitored by continuous cardiac monitoring, twice daily performed 12- or 18-lead ECGs and timely ECG checks when cardiac symptoms occurred. Follow-up visits were routinely scheduled after discharge. Primary outcomes were all-cause death and cardiovascular death occurring during hospitalization and long-term follow-up. Secondary outcome was MACEs during hospitalization. RESULTS: During the median hospital stay of 9.0 (7.0, 11.0) days, new-onset AF was documented in 133 (3.48%) patients; 95 (71.43%) patients had AF attacks within 3 days following AMI. Independent risk factors associated with new-onset AF were older age, larger left atrial diameter, higher level of NT-proBNP, and primary PCI. New-onset AF was found to be significantly associated with in-hospital all-cause death (OR 4.33, 95%CI: 2.37-7.89, P < 0.001), cardiovascular death (OR 4.10, 95%CI: 2.18-7.73, P < 0.001), and MACEs (OR 2.51, 95%CI: 1.46-4.33, P = 0.001). A total of 112 new-onset AF and 3,338 non-AF patients were followed up for 1,090 (365, 1,694) days after discharge. There was no significant association between new-onset AF and long-term all-cause death (HR 1.21, 95%CI: 0.77-1.92, P = 0.406) or cardiovascular death (HR 1.09, 95%CI: 0.61-1.97, P = 0.764). CONCLUSION: New-onset AF following AMI is strongly associated with an increased risk of adverse in-hospital prognosis, but it does not affect prognosis in those who survive until hospital discharge

A Short Review of U. S. Naval Ship Concept Design Technology Development Features

In present study, a history analysis and review of last 30 years for U.S. naval ship concept design development trend is proposed. Based on the development of naval ship concept design model history, the three features of development process are further summarized. The first is that model-based system engineering (MBSE) becomes the basic of naval ship concept design, while the second one is that the multi-discipline crossing and combination becomes a general innovation model. And the third one is that systematization oriented naval system integration is the developing goal. Some detailed examples are presented to illustrate these three characteristics. Finally, the technology difficulties in naval ship concept design are also presented

Efficacy and safety of combination therapy with vildagliptin and metformin versus metformin up-titration in Chinese patients with type 2 diabetes mellitus: study design and rationale of the vision study

Background and aim: Limitations of the currently recommended stepwise treatment pathway for type 2 diabetes mellitus (T2DM), especially the failure of monotherapies to maintain good glycemic control, have prompted use of early, more aggressive combination therapies. The VISION study is designed to explore the efficacy and safety of vildagliptin as an add-on to metformin therapy compared with up-titration of metformin monotherapy in Chinese patients with T2DM. Methods: VISION, a 24-week, phase 4, prospective, randomized, multicenter, open-label, parallel-group study, will include 3312 Chinese T2DM patients aged &gt;= 18 years who are inadequately controlled (6.5% &gt;HbA1c &lt;= 9%) by metformin (750-1000 mg/day). Eligible patients will be randomized to receive either vildagliptin plus metformin or up-titration of metformin monotherapy (5: 1). Patients will also be subgrouped (1: 1: 1: 1) based on their age and body mass index (BMI): &lt;60 years and &lt;24 kg/m(2); &lt;60 years and &gt;= 24 kg/m(2); &gt;= 60 years and &lt;24 kg/m(2); and &gt;= 60 years and &gt;= 24 kg/m(2). Conclusion: The VISION study will test the hypothesis that early use of combination therapy with vildagliptin and metformin will provide good glycemic control and will be better tolerated than up-titration of metformin monotherapy. The study will also correlate these benefits with age and BMI.Cardiac &amp; Cardiovascular SystemsEndocrinology &amp; MetabolismSCI(E)PubMed1ARTICLE1181

Observation of a Near-Threshold Structure in the K+ Recoil-Mass Spectra in e+⁢e−→K+⁢(D−s⁢D*0+D*− s⁢D0)

We report a study of the processes of e+⁢e− →K+⁢D− s⁢D*0 and K+⁢D*−s⁢D0 based on e+⁢e− annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb−1. An excess of events over the known contributions of the conventional charmed mesons is observed near the D−s⁢D*0 and D*−s⁢D0 mass thresholds in the K+ recoil-mass spectrum for events collected at √s =4.681 GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5+1.8 −2.6±2.1) MeV/c2 and (12.8+5.3 −4.4 ±3.0) MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 σ over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into D− s⁢D*0 and D*− s⁢D0. However, the properties of the excess need further exploration with more statistics

Study of e+e−→2(pp¯) at center-of-mass energies between 4.0 and 4.6 GeV

Using data taken at 23 center-of-mass energies between 4.0 and 4.6 GeV with the BESIII detector at the Beijing Electron Positron Collider and with a total integrated luminosity of approximately 15 fb-1, the process e+e-→2(pp¯) is studied for the first time. The Born cross sections for e+e-→2(pp¯) are measured, and no significant structure is observed in the lineshape. The baryon pair (pp and p¯p¯) invariant mass spectra are consistent with phase space, therefore no hexaquark or di-baryon state is found

Cross section measurement of e+e−→pp¯η and e+e−→pp¯ω at center-of-mass energies between 3.773 GeV and 4.6 GeV

Based on 14.7 fb-1 of e+e- annihilation data collected with the BESIII detector at the BEPCII collider at 17 different center-of-mass energies between 3.7730 GeV and 4.5995 GeV, Born cross sections of the two processes e+e-→pp¯η and e+e-→pp¯ω are measured for the first time. No indication of resonant production through a vector state V is observed, and upper limits on the Born cross sections of e+e-→V→pp¯η and e+e-→V→pp¯ω at the 90% confidence level are calculated for a large parameter space in resonance masses and widths. For the current world average parameters of the ψ(4230) of m=4.2187 GeV/c2 and Γ=44 MeV, we find upper limits on resonant production of the pp¯η and pp¯ω final states of 7.5 pb and 10.4 pb at the 90% CL, respectively

Amplitude analysis and branching fraction measurement of Ds+→K−K+π+π0

The first amplitude analysis of the decay Ds+→K-K+π+π0 is presented using the data samples, corresponding to an integrated luminosity of 6.32 fb-1, collected with the BESIII detector at e+e- center-of-mass energies between 4.178 and 4.226 GeV. More than 3000 events selected with a purity of 97.5% are used to perform the amplitude analysis, and nine components are found necessary to describe the data. Relative fractions and phases of the intermediate decays are determined. With the detection efficiency estimated by the results of the amplitude analysis, the branching fraction of Ds+→K-K+π+π0 decay is measured to be (5.42±0.10stat±0.17syst)

Search for the reaction e+e−→χcJπ+π− and a charmoniumlike structure decaying to χcJπ± between 4.18 and 4.60 GeV

We search for the process e+e-→χcJπ+π- (J=0, 1, 2) and for a charged charmoniumlike state in the χcJπ± subsystem. The search uses datasets collected with the BESIII detector at the BEPCII storage ring at center-of-mass energies between 4.18 GeV and 4.60 GeV. No significant χcJπ+π- signals are observed at any center-of-mass energy, and thus upper limits are provided which also serve as limits for a possible charmoniumlike structure in the invariant χcJπ± mass