227 research outputs found

    H-Dibaryon from Lattice QCD with Improved Anisotropic Actions

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    The six quark state(uuddss) called H dibaryon(JP=0+J^P=0^+,S=2S=-2) has been calculated to study its existence and stability. The simulations are performed in quenched QCD on 83×248^3 \times 24 and 163×4816^3 \times 48 anisotropic lattices with Symanzik improved gauge action and Clover fermion action. The gauge coupling is β=2.0\beta=2.0 and aspect ratio ξ=as/at=3.0\xi=a_s/a_t=3.0. Preliminary results indicate that mass of H dibaryon is 2134(100)Mev on 83×248^3 \times 24 lattice and 2167(59)Mev on 163×4816^3 \times 48 respectively. It seems that the radius of H dibaryon is very large and the finite size effect is very obvious

    Search for H dibaryon on the lattice

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    We investigate the H-dibaryon, an I(JP)=0(0+)I(J^{P})=0(0^{+}) with s=2s=-2, in the chiral and continuum regimes on anisotropic lattices in quenched QCD. Simulations are performed on very coarse lattices with refined techniques to obtain results with high accuracy over a spatial lattice spacing in the range of as0.190.41a_{s} \sim 0.19 - 0.41 fm. We present results for the energy difference between the ground state energy of the hexa-quark stranglet and the free two-baryon state from our ensembles. A negative binding energy observed in the chirally extrapolated results leads to the conclusion that the measured hexa-quark state is bound. This is further confirmed by the attractive interaction in the continuum limit with the observed H-dibaryon bound by 47\sim 47 MeV.Comment: 7 pages, 5 figures, Accepted for publication in Phys. Rev.

    Reinforcement Learning Based Robust Volt/Var Control in Active Distribution Networks With Imprecisely Known Delay

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    Active distribution networks (ADNs) incorporating massive photovoltaic (PV) devices encounter challenges of rapid voltage fluctuations and potential violations. Due to the fluctuation and intermittency of PV generation, the state gap, arising from time-inconsistent states and exacerbated by imprecisely known system delays, significantly impacts the accuracy of voltage control. This paper addresses this challenge by introducing a framework for delay adaptive Volt/Var control (VVC) in the presence of imprecisely known system delays to regulate the reactive power of PV inverters. The proposed approach formulates the voltage control, based on predicted system operation states, as a robust VVC problem. It employs sample selection from the state prediction interval to promptly identify the worst-performing system operation state. Furthermore, we leverage the decentralized partially observable Markov decision process (Dec-POMDP) to reformulate the robust VVC problem. We design Multiple Policy Networks and employ Multiple Policy Networks and Reward Shaping-based Multi-agent Twin Delayed Deep Deterministic Policy Gradient (MPNRS-MATD3) algorithm to efficiently address and solve the Dec-POMDP model-based problem. Simulation results show the delay adaption characteristic of our proposed framework, and the MPNRS-MATD3 outperforms other multi-agent reinforcement learning algorithms in robust voltage control

    Critical Behavior of Ferromagnetic Ising Model on Triangular Lattice

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    We apply a new updating algorithm scheme to investigate the critical behavior of the two-dimensional ferromagnetic Ising model on a triangular lattice with nearest neighbour interactions. The transition is examined by generating accurate data for large lattices with L=8,10,12,15,20,25,30,40,50L=8,10,12,15,20,25,30,40,50. The spin updating algorithm we employ has the advantages of both metropolis and single-update methods. Our study indicates that the transition to be continuous at Tc=3.6403(2)T_c=3.6403(2). A convincing finite-size scaling analysis of the model yield ν=0.9995(21)\nu=0.9995(21), β/ν=0.12400(18)\beta/\nu=0.12400(18), γ/ν=1.75223(22)\gamma/\nu=1.75223(22), γ/ν=1.7555(22)\gamma'/\nu=1.7555(22), α/ν=0.00077(420)\alpha/\nu=0.00077(420) (scaling) and α/ν=0.0010(42)\alpha/\nu=0.0010(42)(hyperscaling) respectively. Estimates of present scheme yield accurate estimates for all critical exponents than those obtained with Monte Carlo methods and show an excellent agreement with their well-established predicted values

    3-Chloro­pyridin-2-amine

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    In the title compound, C5H5ClN2, a by-product in the synthesis of ethyl 2-(3-chloro­pyridin-2-yl)-5-oxopyrazolidine-3-carboxyl­ate, the amine groups form inter­molecular hydrogen-bonding associations with pyridine N-atom acceptors, giving centrosymmetric cyclic dimers. Short inter­molecular Cl⋯Cl inter­actions [3.278 (3) Å] also occur

    Poly[[μ2-aqua-μ3-(4-carb­oxy-2-propyl-1H-imidazole-5-carboxyl­ato-κ4 N 3,O 4:O 4:O 5)-sodium] hemihydrate]

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    In the title compound, {[Na(C8H9N2O4)(H2O)]·0.5H2O}n, the Na+ ion is coordinated by two bridging water mol­ecules, one N atom and three O atoms from three 4-carb­oxy-2-propyl-1H-imidazole-5-carboxyl­ate (H2pimdc) ligands. Adjacent Na+ ions are linked alternately by two water O atoms and two carb­oxy O atoms into a chain along [001]. These chains are connected through the coordination of the carboxyl­ate O atoms to the Na+ ions, forming a three-dimensional structure. An intra­molecular O—H⋯O hydrogen bond and inter­molecular N—H⋯O and O—H⋯O hydrogen bonds are present in the crystal structure

    Lowest-lying Tetra-Quark Hadrons in Anisotropic Lattice QCD

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    We present a detailed study of lowest-lying q2qˉ2q^{2}\bar{q}^{2} hadrons in quenched improved anisotropic lattice QCD. Using the ππ\pi\pi and diquark-antidiquark local and smeared operators, we attempt to isolate the signal for I(JP)=0(0+),2(0+)I(J^{P})=0(0^{+}), 2(0^{+}) and 1(1+)1(1^{+}) states in two flavour QCD. In the chiral limit of light-quark mass region, the lowest scalar 4q4q state is found to have a mass, m4qI=0=927(12)m^{I=0}_{4q}=927(12) MeV, which is slightly lower than the experimentally observed f0(980)f_{0}(980). The results from our variational analysis do not indicate a signature of a tetraquark resonance in I=1 and I=2 channels. After the chiral extrapolation the lowest 1(1+)1(1^{+}) state is found to have a mass, m4qI=1=1358(28)m^{I=1}_{4q}=1358(28) MeV. We analysed the static 4q4q potential extracted form a tetraquark Wilson loop and illustrated the behaviour of the 4q4q state as a bound state, unbinding at some critical diquark separation. From our analysis we conclude that scalar 4q4q system appears as a two-pion scattering state and that there is no spatially-localised 4q4q state in the light-quark mass region.Comment: 9 pages, 10 figure

    A novel 7-chemokine-genes predictive signature for prognosis and therapeutic response in renal clear cell carcinoma

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    Background: Renal clear cell carcinoma (ccRCC) is one of the most prevailing type of malignancies, which is affected by chemokines. Chemokines can form a local network to regulate the movement of immune cells and are essential for tumor proliferation and metastasis as well as for the interaction between tumor cells and mesenchymal cells. Establishing a chemokine genes signature to assess prognosis and therapy responsiveness in ccRCC is the goal of this effort.Methods: mRNA sequencing data and clinicopathological data on 526 individuals with ccRCC were gathered from the The Cancer Genome Atlas database for this investigation (263 training group samples and 263 validation group samples). Utilizing the LASSO algorithm in conjunction with univariate Cox analysis, the gene signature was constructed. The Gene Expression Omnibus (GEO) database provided the single cell RNA sequencing (scRNA-seq) data, and the R package “Seurat” was applied to analyze the scRNA-seq data. In addition, the enrichment scores of 28 immune cells in the tumor microenvironment (TME) were calculated using the “ssGSEA” algorithm. In order to develop possible medications for patients with high-risk ccRCC, the “pRRophetic” package is employed.Results: High-risk patients had lower overall survival in this model for predicting prognosis, which was supported by the validation cohort. In both cohorts, it served as an independent prognostic factor. Annotation of the predicted signature’s biological function revealed that it was correlated with immune-related pathways, and the riskscore was positively correlated with immune cell infiltration and several immune checkpoints (ICs), including CD47, PDCD1, TIGIT, and LAG-3, while it was negatively correlated with TNFRSF14. The CXCL2, CXCL12, and CX3CL1 genes of this signature were shown to be significantly expressed in monocytes and cancer cells, according to scRNA-seq analysis. Furthermore, the high expression of CD47 in cancer cells suggested us that this could be a promising immune checkpoint. For patients who had high riskscore, we predicted 12 potential medications.Conclusion: Overall, our findings show that a putative 7-chemokine-gene signature might predict a patient’s prognosis for ccRCC and reflect the disease’s complicated immunological environment. Additionally, it offers suggestions on how to treat ccRCC using precision treatment and focused risk assessment
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