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Abstract. Stratospheric water vapor is an important greenhouse gas, which affects the radiation balance and temperature structure of the stratosphere and troposphere. Although previous studies have investigated the water vapor variability associated with the quasi-biennial oscillation (QBO), the seasonal difference in the water vapor QBO are still not well understood. Using the ERA5 reanalysis and SWOOSH observations, this study compares the stratospheric water vapor distribution in northern winter and summer under different QBO phases. The water vapor and zonal winds are positively correlated in the mid-to-lower stratosphere; however this relationship weakens in the northern summer. The mean vertical transport term via the QBO related residual circulation is the leading factor controlling the water vapor distribution in most of the stratosphere. This dynamic transport of water vapor in the lower stratosphere by the residual circulation is larger in boreal winter than in summer. Further, the dehydration effect by cold temperature in the lower stratosphere is also more effective in boreal winter than in summer. Tropical deep convection exhibits opposite variations for a given QBO phase in boreal winter versus summer especially over the Indo-Pacific Oceans. This further enhances the temperature difference between the QBO easterly and westerly phases in winter and reduces the temperature contrast in summer. It is still a challenge for models to reproduce the water vapor QBO: CMIP6 models tend to underestimate the water vapor QBO amplitude, and the seasonal contrast in the water vapor QBO between boreal winter and summer is underrepresented in most models.
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Abstract
Based on a sample of (2712.4 ± 14.3) × 106
ψ(3686) events collected with the BESIII detector, a partial wave analysis of the decay
$$ \psi (3686)\to \Lambda {\overline{\Sigma}}^0{\pi}^0 $$
ψ
3686
→
Λ
Σ
¯
0
π
0
+ c.c. is performed to investigate Λ* and Σ* resonances in the
$$ {\pi}^0{\overline{\Sigma}}^0 $$
π
0
Σ
¯
0
and π
0Λ invariant mass distributions. Significant contributions are found from the Λ(1405), Λ(1520), Λ(1600), Λ(1670), Λ(1690), Λ(1800), Λ(1890), Λ(2325), Σ(1385), Σ(1660), Σ(1670), Σ(1750), and Σ(1910). The masses, widths, and production branching fractions for each component are determined. In addition, the branching fraction of
$$ \psi (3686)\to \Lambda {\overline{\Sigma}}^0{\pi}^0 $$
ψ
3686
→
Λ
Σ
¯
0
π
0
+ c.c. is measured to be (1.544 ± 0.013 ± 0.071) × 10
−4 for the first time, where the first uncertainty is statistical and the second systematic.- Book : 2025(2)
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2025
Background and Objectives: Single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is a well-established technique for evaluating myocardial perfusion and function in patients with suspected or known coronary artery disease. While conventional dual-detector SPECT scanners have limitations in spatial resolution and photon detection sensitivity, recent advancements, including full-ring solid-state cadmium zinc telluride (CZT) detectors, offer enhanced image quality and improved diagnostic accuracy. This study aimed to compare the performance of Veriton-CT, a full-ring CZT SPECT system, with GE Discovery 530c, a dedicated cardiac fixed-angle gamma camera, in myocardial perfusion imaging and their correlation with coronary angiography findings. Materials and Methods: This was a prospective study that analyzed 21 patients who underwent MPI at the Department of Nuclear Medicine, Lithuanian University of Health Sciences, Kauno Klinikos. A one-day stress–rest protocol using 99mTc-Sestamibi was employed, with stress testing performed via bicycle ergometry or pharmacological induction. MPI was first conducted using GE Discovery 530c (GE Health Care, Boston, MA, USA), followed by imaging on Veriton-CT, which included low-dose CT for attenuation correction. The summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) were analyzed and compared between both imaging modalities. Coronary angiography results were retrospectively collected, and lesion-based analysis was performed to assess the correlation between imaging results and the presence of significant coronary artery stenosis (≥35% and ≥70% narrowing). Image quality and the certainty of distinguishing the inferior myocardial wall from extracardiac structures were also evaluated by two independent researchers with differing levels of experience. Results: Among the 14 patients included in the final analysis, Veriton-CT was more likely to classify MPI scans as normal (64.3%) compared to GE Discovery 530c (28.6%). Additionally, Veriton-CT provided a better assessment of the right coronary artery (RCA) basin, showing greater agreement with coronary angiography findings than GE Discovery 530c, although the difference was not statistically significant. No significant differences in lesion overlap were observed for the left anterior descending artery (LAD) or left circumflex artery (LCx) basins. Furthermore, the image quality assessment revealed slightly better delineation of extracardiac structures using Veriton-CT (Spectrum Dynamics Medical, Caesarea, Israel), particularly when evaluated by an experienced researcher. However, no significant difference was observed when assessed by a less experienced observer. Conclusions: Our findings suggest that Veriton-CT, with its full-ring CZT detector system, may offer advantages over fixed-angle gamma cameras in improving image quality and reducing attenuation artifacts in MPI. Although the difference in correlations with coronary angiography findings was not statistically significant, Veriton-CT showed a trend toward better agreement, particularly in the RCA basin. These results indicate that full-ring SPECT imaging could improve the diagnostic accuracy of non-invasive MPI, potentially reducing the need for unnecessary invasive angiography. Further studies with larger patient cohorts are required to confirm these findings and evaluate the clinical impact of full-ring SPECT technology in myocardial perfusion imaging.- Book : 61(4)
- Pub. Date : 2025
- Page : pp.665-665
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Background Research with neutrons is usually related to the use of fission-based research reactors or neutron spallation sources to offer neutron beams for science and industry. In recent years a novel way for the production of brilliant cold, thermal, and epithermal neutron beams has emerged with the availability of high current proton accelerator systems. These “High-Current Accelerator-driven Neutron Sources” (HiCANS) offer pulsed neutron beams with high peak brilliance close to present day neutron sources. Methods A project was launched at the Jülich Centre for Neutron Science for the development, design and demonstration of such an innovative high-current accelerator driven neutron source termed “High-Brilliance neutron Source” (HBS). The aim of the project is to construct a scalable neutron source as a user facility. The basic technical components consist of i) a high current proton accelerator with a proton energy below 100 MeV, ii) a compact neutron target, moderator and reflector unit and iii) a neutron extracting, and transport system optimized for neutron beams with high brilliance to serve a suite of high performing instruments with epithermal, thermal and cold neutrons for various applications. Results and Conclusions The HBS project will offer open access and services to the various and changing demands the scientific and also the industrial community asks for. The project offers flexible solutions to a broadest scale of applications in science and industry. The conceptual design of HBS as well as the technical design was published recently in a series of reports as blueprint of a HiCANS facility. HBS will complement and develop further the landscape of high-end neutron facilities in Europe. In addition, HBS will allow intense training and preparation for experiments at the highest level at flagship European neutron sources such as the ILL or, in the future, at the ESS.- Book : 3()
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- Page : pp.10-10
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