We report a study of the processes of e^{+}e^{-}→K^{+}D_{s}^{-}D^{*0} and K^{+}D_{s}^{*-}D^{0} 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}^{*-}D^{0} mass thresholds in the K^{+} recoil-mass spectrum for events collected at sqrts=4.681 GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5_{-2.6}^{+1.8}±2.1) MeV/c^{2} and (12.8_{-4.4}^{+5.3}±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}^{*-}D^{0}. However, the properties of the excess need further exploration with more statistics.
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Abstract
We report on analysis of observations of the bright transient X-ray pulsar Swift J0243.6+6124 obtained during its 2017-2018 giant outburst with Insight-HXMT, NuSTAR, and Swift observatories. ...We focus on the discovery of a sharp state transition of the timing and spectral properties of the source at super-Eddington accretion rates, which we associate with the transition of the accretion disk to a radiation pressure dominated (RPD) state, the first ever directly observed for magnetized neutron star. This transition occurs at slightly higher luminosity compared to already reported transition of the source from sub- to super-critical accretion regime associate with onset of an accretion column. We argue that this scenario can only be realized for comparatively weakly magnetized neutron star, not dissimilar to other ultra-luminous X-ray pulsars (ULPs), which accrete at similar rates. Further evidence for this conclusion is provided by the non-detection of the transition to the propeller state in quiescence which strongly implies compact magnetosphere and thus rules out magnetar-like fields.
In strongly correlated systems the strength of Coulomb interactions between electrons, relative to their kinetic energy, plays a central role in determining their emergent quantum mechanical phases. ...We perform resonant x-ray scattering on Bi
Sr
CaCu
O
, a prototypical cuprate superconductor, to probe electronic correlations within the CuO
plane. We discover a dynamic quasi-circular pattern in the x-y scattering plane with a radius that matches the wave vector magnitude of the well-known static charge order. Along with doping- and temperature-dependent measurements, our experiments reveal a picture of charge order competing with superconductivity where short-range domains along x and y can dynamically rotate into any other in-plane direction. This quasi-circular spectrum, a hallmark of Brazovskii-type fluctuations, has immediate consequences to our understanding of rotational and translational symmetry breaking in the cuprates. We discuss how the combination of short- and long-range Coulomb interactions results in an effective non-monotonic potential that may determine the quasi-circular pattern.
We prospectively investigated the diagnostic accuracy of contrast-free 3-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) with volume rendering (VR) at 3.0 T to detect ...intracranial aneurysms in a large cohort of patients.
We conducted a prospective clinical study including 411 patients with suspected aneurysms and other cerebral vascular diseases who were referred for contrast-free 3D-TOF-MRA at 3.0 T prior to digital subtraction angiography (DSA). 2D-DSA and VR-DSA were regarded as the gold standard. Forty-two patients were excluded. Accuracy, sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV) as measures to detect or rule out intracranial aneurysms were determined by patient-, aneurysm-, vessel-, and aneurysm size-based evaluations.
In all 369 patients investigated, VR-DSA revealed 307 aneurysms in 246 patients (66.7%) and no aneurysm in 123 patients. The patient-based evaluation by VR 3D-TOF-MRA at 3.0 T yielded an accuracy of 97.6%, a sensitivity of 99.2%, specificity of 94.4%, PPV of 97.2%, and NPV of 98.3% in the detection of intracranial aneurysms. The aneurysm-based evaluation yielded an accuracy of 98.3%, sensitivity of 99.3%, specificity of 96.9%, PPV of 97.8%, and NPV of 99.1%. The vessel-based evaluation yielded accuracy of 98.8%, sensitivity of 99.2%, specificity of 98.5%, PPV of 97.5%, and NPV of 99.6%. The evaluation based on aneurysm sizes yielded similar results.
VR 3D-TOF-MRA at 3.0 T accurately identified the presence of intracranial aneurysms. High PPV and NPV indicated that VR 3D-TOF-MRA at 3.0 T may replace DSA as a contrast-free, noninvasive, and non-radiation-based modality for the diagnosis and screening of intracranial aneurysms.
The processes X(3872) ... , and γD+D− are searched for in a 9.0 fb−1 data sample collected at center-of-mass energies between 4.178 and 4.278 GeV with the BESIII detector. We observe X(3872) ... . ...and find evidence for X (3872)→γJ/ψ with statistical significances of 7.4 σ and 3.5σ, respectively. No evident signals for X(3872)→γψ(2S) and γD+D− are found, and the upper limit on the relative branching ratio Rγψ ≡ {BX(3872)→γψ(2S)}/{BX(3872)→γJ/ψ} <0.59 is set at 90% confidence level. Measurements of branching ratios relative to decay X(3872)→π+π−J/ψ are also reported for decays ... .,γψ(2S), γJ/ψ, and γD+D−, as well as the non-... three-body decays ... .(ProQuest: ... denotes formulae omitted.)
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Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron-Positron Collider II storage rings, the value of ...R≡σ(e^{+}e^{-}→hadrons)/σ(e^{+}e^{-}→μ^{+}μ^{-}) is measured at 14 center-of-mass energies from 2.2324 to 3.6710 GeV. The resulting uncertainties are less than 3.0% and are dominated by systematic uncertainties.
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Abstract Objective To evaluate the role of circulating tumour cells (CTCs) in patients with endometrial cancer (EC). Study design This study included 40 patients with a pre-operative diagnosis of ...high-risk EC between April 2015 and May 2016. Patients were further divided into high-risk (grade 3, non-endometrioid, myometrial invasion ≥1/2 and stage II–IV) and high–intermediate-risk (grade 2–3, endometrioid, myometrial invasion <1/2 and stage I–II) groups according to postoperative pathological results. CTCs were detected using the CellSearch system, and CTC results were correlated with standard clinicopathological characteristics and serum tumour marker CA125/HE4 status using Chi-squared test, continuity correction or Fisher’s exact test. The pharmacodynamic effect was detected after the first cycle of adjuvant therapy. Patients were followed up for 13 months to assess outcomes. Results Fifteen percent of patients had one or more CTCs. The presence of CTCs was found to be significantly associated with cervical involvement (83.33% vs 11.76%, p = 0.00). No significant difference in CTC-positive rates was detected between the high-risk and high–intermediate-risk groups, and no significant correlation was found between CTCs and serum CA125/HE4, either by positive rates or exact serum levels of the conventional tumour markers. No more CTCs were detected after the first cycle of standard chemotherapy in this study, and no distant metastases or recurrence were found in the CTC-positive patients during the follow-up period. Conclusion The presence of CTCs was correlated with cervical involvement. Early-stage EC patients with CTCs may benefit from additional adjuvant therapies. Assessment of CTCs may be useful in the management of high-risk EC patients.
We present an analysis of the process ψ(3686)→Ω^{-}Ωover ¯^{+} (Ω^{-}→K^{-}Λ, Ωover ¯^{+}→K^{+}Λover ¯, Λ→pπ^{-}, Λover ¯→pover ¯π^{+}) based on a dataset of 448×10^{6} ψ(3686) decays collected with ...the BESIII detector at the BEPCII electron-positron collider. The helicity amplitudes for the process ψ(3686)→Ω^{-}Ωover ¯^{+} and the decay parameters of the subsequent decay Ω^{-}→K^{-}Λ (Ωover ¯^{+}→K^{+}Λover ¯) are measured for the first time by a fit to the angular distribution of the complete decay chain, and the spin of the Ω^{-} is determined to be 3/2 for the first time since its discovery more than 50 years ago.
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► Friction–velocity thresholds (u*Th) are commonly used to filter nighttime NEE. ► Change-point detection (CPD) is used to improve automated u*Th evaluation. ► The technique is evaluated at 38 sites ...from the North American Carbon Program. ► At most sites, CPD produced robust u*Th estimates that were comparable among years. ► The results support the pragmatic use of u*Th filters.
The eddy-covariance method often underestimates fluxes under stable, low-wind conditions at night when turbulence is not well developed. The most common approach to resolve the problem of nighttime flux underestimation is to identify and remove the deficit periods using friction–velocity (u*) threshold filters (u*Th). This study modifies an accepted method for u*Th evaluation by incorporating change-point-detection techniques. The original and modified methods are evaluated at 38 sites as part of the North American Carbon Program (NACP) site-level synthesis. At most sites, the modified method produced u*Th estimates that were higher and less variable than the original method. It also provided an objective method to identify sites that lacked a u*Th response. The modified u*Th estimates were robust and comparable among years. Inter-annual u*Th differences were small, so that a single u*Th value was warranted at most sites. No variation in the u*Th was observed by time of day (dusk versus mid or late night), however, a few sites showed significant u*Th variation with time of year. Among-site variation in the u*Th was strongly related to canopy height and the mean annual nighttime u*. The modified u*Th estimates excluded a high fraction of nighttime data – 61% on average. However, the negative impact of the high exclusion rate on annual net ecosystem production (NEP) was small compared to the larger impact of underestimating the u*Th. Compared to the original method, the higher u*Th estimates from the modified method caused a mean 8% reduction in annual NEP across all site-years, and a mean 7% increase in total ecosystem respiration (Re). The modified method also reduced the u*Th-related uncertainties in annual NEP and Re by more than 50%. These results support the use of u*Th filters as a pragmatic solution to a complex problem.
•Sm2O3 is well coated on LiLi0.2Mn0.56Ni0.16Co0.08O2 by simple wet chemical method.•The coated sample exhibits high capacity of 234.5mAhg−1 at 1C.•Capacity retention of 91.5% is obtained at 1C ...(200mAg−1) after 80 cycles 25°C.•EIS shows the thin Sm2O3 layer mainly reduces the charge transfer resistance.
Sm2O3-modified LiLi0.2Mn0.56Ni0.16Co0.08O2 was synthesized via a simple wet chemical process followed by a solid state reaction. A thin Sm2O3 layer with a thickness of about 2.5nm was uniformly coated on the surface of the Li-rich layered oxide particles. After Sm2O3 surface modification, high discharge capacity of 214.6mAhg−1 with a retention of 91.5% is obtained at a current density of 200mAg−1 between 2.0V and 4.8V after 80 cycles. Electrochemical impedance spectroscopy (EIS) shows that the thin Sm2O3 layer mainly reduces the charge transfer resistance and stabilizes the surface structure of the active material during cycling. Sm2O3 modification will be a promising approach to improve the cyclic stability of Li-rich layered oxides.
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