646 research outputs found
Broadband multi-wavelength study of LHAASO detected AGN
Recently, the Large High Altitude Air Shower Observatory (LHAASO)
collaboration presents the first catalog of -ray sources using 508 days
LHAASO data from March 2021 to September 2022. This catalog contains five
active galactic nuclei (AGNs), of which four are blazars and one is a
liner-type AGN. In this work, we establish averaged multi-wavelength SEDs by
combining data from -Large Area Telescope, , , and
with the same period as the LHAASO detection. In general, these five AGNs are
found in low states at all wavelengths. To study the multi-wavelength
properties of these AGNs, several jet emission models, including the one-zone
leptonic model, the one-zone leptonic and hadronuclear () model, the
one-zone proton-synchrotron model, and the spine-layer model are applied to
reproduce their averaged SEDs, respectively. We find that the one-zone leptonic
model can reproduce most of the SEDs, except for the high-energy tail of LHAASO
spectra. To improve the fitting, emission from interactions is favoured in
the framework of one-zone model. The spine-layer model, which can be treated as
a multi-zone scenario, also can provide good spectra fits. The influence of
different extragalactic background light models on fitting LHAASO energy
spectrum is also discussed.Comment: 22 pages, 10 figures, submitted to ApJS. Suggestions, comments or
feedback will be appreciate
A multi-objective optimal PID control for a nonlinear system with time delay
It is generally difficult to design feedback controls of nonlinear systems with time delay to meet time domain specifications such as rise time, overshoot, and tracking error. Furthermore, these time domain specifications tend to be conflicting to each other to make the control design even more challenging. This paper presents a cell mapping method for multi-objective optimal feedback control design in time domain for a nonlinear Duffing system with time delay. We first review the multi-objective optimization problem and its formulation for control design. We then introduce the cell mapping method and a hybrid algorithm for global optimal solutions. Numerical simulations of the PID control are presented to show the features of the multi-objective optimal design
Molecular cloning, expression pattern, and putative cis-acting elements of a 4-coumarate:CoA ligase gene in bamboo ( Neosinocalamus affinis )
Background: 4-coumarate:CoA ligase (4CL) plays an important role at the
divergence point from general phenylpropanoid metabolism to several
branch pathways. Although 4CL sin higher plants have been extensively
studied, little has known about the 4CL gene of bamboo. Results: In
current study, a Na4CL gene putative encoding 4-coumarate:CoA ligase
(4CL) and its 5\u2019-flanking region were isolated from bamboo
(Neosinocalamus affinis) by RACE-PCR and genomic DNA walker,
respectively. Na4CL encodes a predicted protein of 557 amino acids,
with conserved motifs of adenylate-forming enzymes. Phylogenetic
analysis showed that Na4CL shared 62~85% identity with other known
plant 4CLs, and cluster closely with some known 4CLs in monocots.
Sequence analysis revealed conserved cis-acting elements (Box A and
AC-II element) present in the Na4CL promoter. Additionally, a Na4CL
RNAi construct was transformed into tobacco. Transgenic tobaccos
displayed significant down-expression of endogenesis 4CL and reduced
lignin contents. Conclusion:These results contribute to the knowledge
of the presence of Na4CL gen and its possible role in phenylpropanoid
metabolism
Agent with Warm Start and Active Termination for Plane Localization in 3D Ultrasound
Standard plane localization is crucial for ultrasound (US) diagnosis. In
prenatal US, dozens of standard planes are manually acquired with a 2D probe.
It is time-consuming and operator-dependent. In comparison, 3D US containing
multiple standard planes in one shot has the inherent advantages of less
user-dependency and more efficiency. However, manual plane localization in US
volume is challenging due to the huge search space and large fetal posture
variation. In this study, we propose a novel reinforcement learning (RL)
framework to automatically localize fetal brain standard planes in 3D US. Our
contribution is two-fold. First, we equip the RL framework with a
landmark-aware alignment module to provide warm start and strong spatial bounds
for the agent actions, thus ensuring its effectiveness. Second, instead of
passively and empirically terminating the agent inference, we propose a
recurrent neural network based strategy for active termination of the agent's
interaction procedure. This improves both the accuracy and efficiency of the
localization system. Extensively validated on our in-house large dataset, our
approach achieves the accuracy of 3.4mm/9.6{\deg} and 2.7mm/9.1{\deg} for the
transcerebellar and transthalamic plane localization, respectively. Ourproposed
RL framework is general and has the potential to improve the efficiency and
standardization of US scanning.Comment: 9 pages, 5 figures, 1 table. Accepted by MICCAI 2019 (oral
Y Chromosomes of 40% Chinese Are Descendants of Three Neolithic Super-grandfathers
Demographic change of human populations is one of the central questions for
delving into the past of human beings. To identify major population expansions
related to male lineages, we sequenced 78 East Asian Y chromosomes at 3.9 Mbp
of the non-recombining region (NRY), discovered >4,000 new SNPs, and identified
many new clades. The relative divergence dates can be estimated much more
precisely using molecular clock. We found that all the Paleolithic divergences
were binary; however, three strong star-like Neolithic expansions at ~6 kya
(thousand years ago) (assuming a constant substitution rate of 1e-9/bp/year)
indicates that ~40% of modern Chinese are patrilineal descendants of only three
super-grandfathers at that time. This observation suggests that the main
patrilineal expansion in China occurred in the Neolithic Era and might be
related to the development of agriculture.Comment: 29 pages of article text including 1 article figure, 9 pages of SI
text, and 2 SI figures. 5 SI tables are in a separate ancillary fil
Estimated glomerular filtration rate is a biomarker of cognitive impairment in Parkinson’s disease
BackgroundsThe relationship between kidney function and cognitive impairment in Parkinson’s disease (PD) is poorly understood and underexplored. This study aims to explore whether renal indices can serve as indicators to monitor the cognitive impairment of PD.MethodsA total of 508 PD patients and 168 healthy controls from the Parkinson’s Progression Markers Initiative (PPMI) were recruited, and 486 (95.7%) PD patients underwent longitudinal measurements. The renal indicators including serum creatinine (Scr), uric acid (UA), and urea nitrogen, as well as UA/Scr ratio and estimated glomerular filtration rate (eGFR), were measured. Cross-sectional and longitudinal associations between kidney function and cognitive impairment were evaluated using multivariable-adjusted models.ResultseGFR was associated with lower levels of cerebrospinal fluid (CSF) Aβ1–42 (p = 0.0156) and α-synuclein (p = 0.0151) and higher serum NfL (p = 0.0215) in PD patients at baseline. Longitudinal results showed that decreased eGFR predicted a higher risk of cognitive impairment (HR = 0.7382, 95% CI = 0.6329–0.8610). Additionally, eGFR decline was significantly associated with higher rates of increase in CSF T-tau (p = 0.0096), P-tau (p = 0.0250), and serum NfL (p = 0.0189), as well as global cognition and various cognitive domains (p < 0.0500). The reduced UA/Scr ratio was also linked to higher NfL levels (p = 0.0282) and greater accumulation of T-tau (p = 0.0282) and P-tau (p = 0.0317). However, no significant associations were found between other renal indices and cognition.ConclusioneGFR is altered in PD subjects with cognitive impairment, and predict larger progression of cognitive decline. It may assist identifying patients with PD at risk of rapid cognitive decline and have the potential to monitoring responses to therapy in future clinical practice
Video-assisted mediastinoscopic transhiatal esophagectomy combined with laparoscopy for esophageal cancer
<p>Abstract</p> <p>Background</p> <p>Minimally invasive transhiatal esophagectomy for esophageal cancer includes mediastinoscopic and laparoscopic transhiatal esophagectomy. It is inadequate in both two techniques. It is impossible to dissect the lower esophagus with single mediastinoscopy or the upper and middle esophagus with single laparoscopy. We use mediastinoscopy combined with laparoscopy to dissect the whole esophagus and stomach including lymph node dissection. In addition, laparoscopic gastric mobilization leads to less trauma than an open gastroplasty.</p> <p>Methods</p> <p>40 cases of video-assisted mediastinoscopic transhiatal esophagectomy were performed and divided into two groups.32 patients were received surgical therapy of single mediastinoscopic esophagectomy with open gastroplasty in group A, while 8 patients were received surgical therapy of mediastinoscopic esophagectomy combined with laparoscopic lower esophageal and gastric dissection in group B. The perioperative complications were recorded.</p> <p>Results</p> <p>Video-assisted mediastinoscopic transhiatal esophagectomy was performed successfully both in group A and B. It suggested that mediastinoscopy combined with laparoscopy be better than single mediastinoscopy because of less blood loss, less pain, shorter ICU stay and complete lower mediastinal lymph nodes resection.</p> <p>Conclusions</p> <p>Video-assisted mediastinoscopic transhiatal esophagectomy combined with laparoscopy is a safe and minimally invasive technique with whole esophagus and mediastinal lymph node dissection in the clear visualization of the mediastinum, reducing the abdominal trauma.</p
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