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Incarcerated Ventral Hernia of T-colon Resulting in Colon Perforation and Intraabdominal Abscess
Probing Transverse Momentum Broadening via Dihadron and Hadron-jet Angular Correlations in Relativistic Heavy-ion Collisions
Dijet, dihadron, hadron-jet angular correlations have been reckoned as
important probes of the transverse momentum broadening effects in relativistic
nuclear collisions. When a pair of high-energy jets created in hard collisions
traverse the quark-gluon plasma produced in heavy-ion collisions, they become
de-correlated due to the vacuum soft gluon radiation associated with the
Sudakov logarithms and the medium-induced transverse momentum broadening. For
the first time, we employ the systematical resummation formalism and establish
a baseline calculation to describe the dihadron and hadron-jet angular
correlation data in and peripheral collisions where the medium effect
is negligible. We demonstrate that the medium-induced broadening and the so-called jet quenching parameter can be
extracted from the angular de-correlations observed in collisions. A
global analysis of dihadron and hadron-jet angular correlation data
renders the best fit for a
quark jet at RHIC top energy. Further experimental and theoretical efforts
along the direction of this work shall significantly advance the quantitative
understanding of transverse momentum broadening and help us acquire
unprecedented knowledge of jet quenching parameter in relativistic heavy-ion
collisions.Comment: 6 pages, 3 figure
Coronary Computed Tomography Angiography—A Promising Imaging Modality in Diagnosing Coronary Artery Disease
BackgroundTraditionally, information on coronary artery lesions is obtained from invasive coronary angiography (CAG). The clinical applicability and diagnostic performance of the newly developed 64-slice multislice computed tomography (MSCT) scanner in coronary angiographic evaluation is not well evaluated.MethodsCoronary computed tomography angiography (CCTA) was performed in 345 patients (119 women, 226 men; mean age, 59.64 ±11.67 years). Concomitant CAG was performed in 53 patients. The diagnostic performance of CCTA for detecting significant lesions was compared with that of CAG by 3 independent cardiologists.ResultsAll CCTA was performed without complication. Comparison between CCTA and CAG was made in the 53 patients who underwent both studies. Sensitivity, specificity and the positive and negative predictive values for the 53 patients were: 81%, 99%, 87% and 99%, respectively.ConclusionThe 64-slice MSCT, developed in recent years, allows reliable noninvasive evaluation of coronary artery morphology, including plaque, stenosis and congenital anomaly. The diagnostic accuracy of MSCT scans for detecting lesions makes it a good imaging substitute for CAG in the evaluation of these coronary segments. [J Chin Med Assoc 2008;71(5):241–246
Ergodic Achievable Rate Analysis and Optimization of RIS-assisted Millimeter-Wave MIMO Communication Systems
Reconfigurable intelligent surfaces (RISs) have emerged as a prospective
technology for next-generation wireless networks due to their potential in
coverage and capacity enhancement. Previous works on achievable rate analysis
of RIS-assisted communication systems have mainly focused on the
rich-scattering environment where Rayleigh and Rician channel models can be
applied. This work studies the ergodic achievable rate of RIS-assisted
multiple-input multiple-output communication systems in millimeter-wave band
with limited scattering under the Saleh-Valenzuela channel model. Firstly, we
derive an upper bound of the ergodic achievable rate by means of majorization
theory and Jensen's inequality. The upper bound shows that the ergodic
achievable rate increases logarithmically with the number of antennas at the
base station (BS) and user, the number of the reflection units at the RIS, and
the eigenvalues of the steering matrices associated with the BS, user and RIS.
Then, we aim to maximize the ergodic achievable rate by jointly optimizing the
transmit covariance matrix at the BS and the reflection coefficients at the
RIS. Specifically, the transmit covariance matrix is optimized by the
water-filling algorithm and the reflection coefficients are optimized using the
Riemannian conjugate gradient algorithm. Simulation results validate the
effectiveness of the proposed optimization algorithms.Comment: 30 pages, 11 figure
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