178 research outputs found
Probing the nuclear deformation with three-particle asymmetric cumulant in RHIC isobar runs
Ru+Ru and Zr+Zr collisions at
GeV provide unique opportunities to study the
geometry and fluctuations raised from the deformation of the colliding nuclei.
Using iEBE-VISHNU hybrid model, we predict ratios between
these two collision systems and demonstrate that the ratios of , as well as the ratios of the involving flow harmonics and
event-plane correlations, are sensitive to quadrupole and
octupole deformations, which provides strong constrain on the shape
differences between Ru and Zr.Comment: 6 pages, 4 figure
Boundary and Entropy-driven Adversarial Learning for Fundus Image Segmentation
Accurate segmentation of the optic disc (OD) and cup (OC)in fundus images
from different datasets is critical for glaucoma disease screening. The
cross-domain discrepancy (domain shift) hinders the generalization of deep
neural networks to work on different domain datasets.In this work, we present
an unsupervised domain adaptation framework,called Boundary and Entropy-driven
Adversarial Learning (BEAL), to improve the OD and OC segmentation performance,
especially on the ambiguous boundary regions. In particular, our proposed BEAL
frame-work utilizes the adversarial learning to encourage the boundary
prediction and mask probability entropy map (uncertainty map) of the target
domain to be similar to the source ones, generating more accurate boundaries
and suppressing the high uncertainty predictions of OD and OC segmentation. We
evaluate the proposed BEAL framework on two public retinal fundus image
datasets (Drishti-GS and RIM-ONE-r3), and the experiment results demonstrate
that our method outperforms the state-of-the-art unsupervised domain adaptation
methods. Codes will be available at https://github.com/EmmaW8/BEAL.Comment: Accepted at MICCAI 201
A Game Theory-Based Obstacle Avoidance Routing Protocol for Wireless Sensor Networks
The obstacle avoidance problem in geographic forwarding is an important issue for location-based routing in wireless sensor networks. The presence of an obstacle leads to several geographic routing problems such as excessive energy consumption and data congestion. Obstacles are hard to avoid in realistic environments. To bypass obstacles, most routing protocols tend to forward packets along the obstacle boundaries. This leads to a situation where the nodes at the boundaries exhaust their energy rapidly and the obstacle area is diffused. In this paper, we introduce a novel routing algorithm to solve the obstacle problem in wireless sensor networks based on a game-theory model. Our algorithm forms a concave region that cannot forward packets to achieve the aim of improving the transmission success rate and decreasing packet transmission delays. We consider the residual energy, out-degree and forwarding angle to determine the forwarding probability and payoff function of forwarding candidates. This achieves the aim of load balance and reduces network energy consumption. Simulation results show that based on the average delivery delay, energy consumption and packet delivery ratio performances our protocol is superior to other traditional schemes
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
A Macromolecular Approach to Eradicate Multidrug Resistant Bacterial Infections while Mitigating Drug Resistance Onset
Polymyxins remain the last line treatment for multidrug-resistant (MDR) infections. As polymyxins resistance emerges, there is an urgent need to develop effective antimicrobial agents capable of mitigating MDR. Here, we report biodegradable guanidinium-functionalized polycarbonates with a distinctive mechanism that does not induce drug resistance. Unlike conventional antibiotics, repeated use of the polymers does not lead to drug resistance. Transcriptomic analysis of bacteria further supports development of resistance to antibiotics but not to the macromolecules after 30 treatments. Importantly, high in vivo treatment efficacy of the macromolecules is achieved in MDR A. baumannii-, E. coli-, K. pneumoniae-, methicillin-resistant S. aureus-, cecal ligation and puncture-induced polymicrobial peritonitis, and P. aeruginosa lung infection mouse models while remaining non-toxic (e.g., therapeutic index—ED50/LD50: 1473 for A. baumannii infection). These biodegradable synthetic macromolecules have been demonstrated to have broad spectrum in vivo antimicrobial activity, and have excellent potential as systemic antimicrobials against MDR infections
Impact of biogenic SOA loading on the molecular composition of wintertime PM2.5 in urban Tianjin: an insight from Fourier transform ion cyclotron resonance mass spectrometry
Biomass burning is one of the key sources of urban aerosols in the North China Plain, especially in winter when the impact of secondary organic aerosols (SOA) formed from biogenic volatile organic compounds (BVOCs) is generally considered to be minor. However, little is known about the influence of biogenic SOA loading on the molecular composition of wintertime organic aerosols. Here, we investigated the water-soluble organic compounds in fine particles (PM2.5) from urban Tianjin by ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Our results show that most of the CHO and CHON compounds were derived from biomass burning; they contain O-poor and highly unsaturated compounds with aromatic rings, which are sensitive to photochemical reactions, and some of which probably contribute to light-absorbing chromophores. Under moderate to high SOA loading conditions, the nocturnal chemistry is more efficient than photooxidation to generate secondary CHO and CHON compounds with high oxygen content. Under low SOA-loading, secondary CHO and CHON compounds with low oxygen content are mainly formed by photochemistry. Secondary CHO compounds are mainly derived from oxidation of monoterpenes. But nocturnal chemistry may be more productive to sesquiterpene-derived CHON compounds. In contrast, the number- and intensity-weight of S-containing groups (CHOS and CHONS) increased significantly with the increase of biogenic SOA-loading, which agrees with the fact that a majority of the S-containing groups are identified as organosulfates and nitrooxy-organosulfates that are derived from the oxidation of BVOCs. Terpenes may be potential major contributors to the chemical diversity of organosulfates and nitrooxy-organosulfates under photo-oxidation. While the nocturnal chemistry is more beneficial to the formation of organosulfates and nitrooxy-organosulfates under low SOA-loading. The SOA-loading is an important factor associating with the oxidation degree, nitrate group content and chemodiversity of nitrooxy-organosulfates. Furthermore, our study suggests that the hydrolysis of nitrooxy-organosulfates is a possible pathway for the formation of organosulfates.</p
Real-time Monitoring for the Next Core-Collapse Supernova in JUNO
Core-collapse supernova (CCSN) is one of the most energetic astrophysical
events in the Universe. The early and prompt detection of neutrinos before
(pre-SN) and during the SN burst is a unique opportunity to realize the
multi-messenger observation of the CCSN events. In this work, we describe the
monitoring concept and present the sensitivity of the system to the pre-SN and
SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is
a 20 kton liquid scintillator detector under construction in South China. The
real-time monitoring system is designed with both the prompt monitors on the
electronic board and online monitors at the data acquisition stage, in order to
ensure both the alert speed and alert coverage of progenitor stars. By assuming
a false alert rate of 1 per year, this monitoring system can be sensitive to
the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos
up to about 370 (360) kpc for a progenitor mass of 30 for the case
of normal (inverted) mass ordering. The pointing ability of the CCSN is
evaluated by using the accumulated event anisotropy of the inverse beta decay
interactions from pre-SN or SN neutrinos, which, along with the early alert,
can play important roles for the followup multi-messenger observations of the
next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure
Potential of Core-Collapse Supernova Neutrino Detection at JUNO
JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve
Detection of the Diffuse Supernova Neutrino Background with JUNO
As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO
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