High-TcT_c superconductivity by mobilizing local spin singlets and possible route to higher TcT_c in pressurized La3_3Ni2_2O7_7

We clarify the pairing mechanism of high-$T_c$ superconductivity in bilayer La$_3$Ni$_2$O$_7$ under high pressure by employing the static auxiliary field Monte Carlo approach to simulate a minimal effective model that contains local $d_{z^2}$ inter-layer spin singlets and metallic $d_{x^2-y^2}$ bands. Superconductivity is induced when the local spin singlet pairs are mobilized and attain long-distance phase coherence by hybridization with the metallic bands. We find a dual role of hybridization that not only induces global phase coherence but also competes with the spin singlet formation. This lead to a tentative phase diagram where $T_c$ varies nonmonotonically with the hybridization, in good correspondence with experimental observation. A roughly linear relation is obtained for realistic hopping and hybridization parameters: $T_c\approx 0.05 J$, where $J$ is the inter-layer superexchange interaction. We emphasize the peculiar tunability of the bilayer structure and propose that $T_c$ may be further enhanced by applying uniaxial pressure along the $c$ axis on superconducting La$_3$Ni$_2$O$_7$. Our work provides numerical evidences for the pairing mechanism of high-$T_c$ superconductivity in La$_3$Ni$_2$O$_7$ and points out a potential route to achieve even higher $T_c$.Comment: 6 pages,4 figure

A computational study on the overload characteristic curves of projectile penetrating metal object

The paper, based on ANSYS/LS-DYNA software, made a computational study on the overload characteristic curves of projectile penetrating metal objects. Adopting Lagrange method, Lagrangian-Eulerian coupling algorithm and SPH method, respectively, simulated the over-load characteristics of projectiles penetrating single-layer steel plates and multi-layer steel and aluminum alloy plates. The results affirmed that the curves agreed well with each other. The curves reached its peak during every penetrating layer and the accelerator peak declined with layers increasing. And the overload value fluctuated around zero during the penetrating interval. The fact, gained from the velocity curves, was that it dropped gradually, however, reached a plateau during the interval, suggesting that the velocity kept constant, and overload value came to zero. The simulation and the experimental results of penetrating the multi-layer aluminum alloy plates were in well accord. Besides, the overload curves shared the same trends with penetrating the multi-layer steel plates

A Longitudinal Study of Identifying and Paying Down Architectural Debt

Architectural debt is a form of technical debt that derives from the gap between the architectural design of the system as it "should be" compared to "as it is". We measured architecture debt in two ways: 1) in terms of system-wide coupling measures, and 2) in terms of the number and severity of architectural flaws. In recent work it was shown that the amount of architectural debt has a huge impact on software maintainability and evolution. Consequently, detecting and reducing the debt is expected to make software more amenable to change. This paper reports on a longitudinal study of a healthcare communications product created by Brightsquid Secure Communications Corp. This start-up company is facing the typical trade-off problem of desiring responsiveness to change requests, but wanting to avoid the ever-increasing effort that the accumulation of quick-and-dirty changes eventually incurs. In the first stage of the study, we analyzed the status of the "before" system, which indicated the impacts of change requests. This initial study motivated a more in-depth analysis of architectural debt. The results of this analysis were used to motivate a comprehensive refactoring of the software system. The third phase of the study was a follow-on architectural debt analysis which quantified the improvements made. Using this quantitative evidence, augmented by qualitative evidence gathered from in-depth interviews with Brightsquid's architects, we present lessons learned about the costs and benefits of paying down architecture debt in practice.Comment: Submitted to ICSE-SEIP 201

MIANet: Aggregating Unbiased Instance and General Information for Few-Shot Semantic Segmentation

Existing few-shot segmentation methods are based on the meta-learning strategy and extract instance knowledge from a support set and then apply the knowledge to segment target objects in a query set. However, the extracted knowledge is insufficient to cope with the variable intra-class differences since the knowledge is obtained from a few samples in the support set. To address the problem, we propose a multi-information aggregation network (MIANet) that effectively leverages the general knowledge, i.e., semantic word embeddings, and instance information for accurate segmentation. Specifically, in MIANet, a general information module (GIM) is proposed to extract a general class prototype from word embeddings as a supplement to instance information. To this end, we design a triplet loss that treats the general class prototype as an anchor and samples positive-negative pairs from local features in the support set. The calculated triplet loss can transfer semantic similarities among language identities from a word embedding space to a visual representation space. To alleviate the model biasing towards the seen training classes and to obtain multi-scale information, we then introduce a non-parametric hierarchical prior module (HPM) to generate unbiased instance-level information via calculating the pixel-level similarity between the support and query image features. Finally, an information fusion module (IFM) combines the general and instance information to make predictions for the query image. Extensive experiments on PASCAL-5i and COCO-20i show that MIANet yields superior performance and set a new state-of-the-art. Code is available at https://github.com/Aldrich2y/MIANet.Comment: Accepted to CVPR 202

Lipid rafts both in cellular membrane and viral envelope are critical for PRRSV efficient infection

AbstractPorcine reproductive and respiratory syndrome virus (PRRSV) represents a significantly economical challenge to the swine industry worldwide. In this study, we investigated the importance of cellular and viral lipid rafts in PRRSV infection. First, we demonstrated that PRRSV glycoproteins, Gp3 and Gp4, were associated with lipid rafts during viral entry, and disruption of cellular lipid rafts inhibited PRRSV entry. We also showed the raft-location of CD163, which might contribute to the glycoproteins–raft association. Subsequently, raft disruption caused a significant reduction of viral RNA production. Moreover, Nsp9 was shown to be distributed in rafts, suggesting that rafts probably serve as a platform for PRRSV replication. Finally, we confirmed that disassembly of rafts on the virus envelope may affect the integrity of PRRSV particles and cause the leakage of viral proteins, which impaired PRRSV infectivity. These findings might provide insights on our understanding of the mechanism of PRRSV infection