Effects of Collisional Decoherence on Multipartite Entanglement - How would entanglement not be relatively common?

We consider the collision model of Ziman {\em et al.} and study the robustness of $N$-qubit Greenberger-Horne-Zeilinger (GHZ), W, and linear cluster states. Our results show that $N$-qubit entanglement of GHZ states would be extremely fragile under collisional decoherence, and that of W states could be more robust than of linear cluster states. We indicate that the collision model of Ziman {\em et al.} could provide a physical mechanism to some known results in this area of investigations. More importantly, we show that it could give a clue as to how $N$-partite distillable entanglement would be relatively rare in our macroscopic classical world.Comment: 10 page

On the Weight Distribution of Weights Less than 2wmin⁡2w_{\min} in Polar Codes

The number of low-weight codewords is critical to the performance of error-correcting codes. In 1970, Kasami and Tokura characterized the codewords of Reed-Muller (RM) codes whose weights are less than $2w_{\min}$, where $w_{\min}$ represents the minimum weight. In this paper, we extend their results to decreasing polar codes. We present the closed-form expressions for the number of codewords in decreasing polar codes with weights less than $2w_{\min}$. Moreover, the proposed enumeration algorithm runs in polynomial time with respect to the code length

Improving the Gilbert-Varshamov Bound by Graph Spectral Method

We improve Gilbert-Varshamov bound by graph spectral method. Gilbert graph $G_{q,n,d}$ is a graph with all vectors in $\mathbb{F}_q^n$ as vertices where two vertices are adjacent if their Hamming distance is less than $d$. In this paper, we calculate the eigenvalues and eigenvectors of $G_{q,n,d}$ using the properties of Cayley graph. The improved bound is associated with the minimum eigenvalue of the graph. Finally we give an algorithm to calculate the bound and linear codes which satisfy the bound

On the Weight Spectrum Improvement of Pre-transformed Reed-Muller Codes and Polar Codes

Pre-transformation with an upper-triangular matrix (including cyclic redundancy check (CRC), parity-check (PC) and polarization-adjusted convolutional (PAC) codes) improves the weight spectrum of Reed-Muller (RM) codes and polar codes significantly. However, a theoretical analysis to quantify the improvement is missing. In this paper, we provide asymptotic analysis on the number of low-weight codewords of the original and pre-transformed RM codes respectively, and prove that pre-transformation significantly reduces low-weight codewords, even in the order sense. For polar codes, we prove that the average number of minimum-weight codewords does not increase after pre-transformation. Both results confirm the advantages of pre-transformation

PMP-Swin: Multi-Scale Patch Message Passing Swin Transformer for Retinal Disease Classification

Retinal disease is one of the primary causes of visual impairment, and early diagnosis is essential for preventing further deterioration. Nowadays, many works have explored Transformers for diagnosing diseases due to their strong visual representation capabilities. However, retinal diseases exhibit milder forms and often present with overlapping signs, which pose great difficulties for accurate multi-class classification. Therefore, we propose a new framework named Multi-Scale Patch Message Passing Swin Transformer for multi-class retinal disease classification. Specifically, we design a Patch Message Passing (PMP) module based on the Message Passing mechanism to establish global interaction for pathological semantic features and to exploit the subtle differences further between different diseases. Moreover, considering the various scale of pathological features we integrate multiple PMP modules for different patch sizes. For evaluation, we have constructed a new dataset, named OPTOS dataset, consisting of 1,033 high-resolution fundus images photographed by Optos camera and conducted comprehensive experiments to validate the efficacy of our proposed method. And the results on both the public dataset and our dataset demonstrate that our method achieves remarkable performance compared to state-of-the-art methods.Comment: 9 pages, 7 figure

A Systematic Approach for Inertial Sensor Calibration of Gravity Recovery Satellites and Its Application to Taiji-1 Mission

High-precision inertial sensors or accelerometers can provide us references of free-falling motions in gravitational field in space. They serve as the key payloads for gravity recovery missions such as the CHAMP, the GRACE-type missions, and the planned Next Generation Gravity Missions. In this work, a systematic method of electrostatic inertial sensor calibrations for gravity recovery satellites is suggested, which is applied to and verified with the Taiji-1 mission. With this method, the complete operating parameters including the scale factors, the center of mass offset vector and the intrinsic biased acceleration can be precisely calibrated with only two sets of short-term in-orbit experiments. Taiji-1 is the first technology demonstration satellite of the "Taiji Program in Space", which, in its final extended phase in 2022, could be viewed as operating in the mode of a high-low satellite-to-satellite tracking gravity mission. Based on the calibration principles, swing maneuvers with time span about 200 s and rolling maneuvers for 19 days were conducted by Taiji-1 in 2022. The inertial sensor's operating parameters are precisely re-calibrated with Kalman filters and are updated to the Taiji-1 science team. Data from one of the sensitive axis is re-processed with the updated operating parameters, and the performance is found to be slightly improved compared with former results. This approach could be of high reference value for the accelerometer or inertial sensor calibrations of the GFO, the Chinese GRACE-type mission, and the Next Generation Gravity Missions. This could also shed some light on the in-orbit calibrations of the ultra-precision inertial sensors for future GW space antennas because of the technological inheritance between these two generations of inertial sensors.Comment: 24 pages, 19 figure

A parametric study of 3D printed polymer gears

The selection of printing parameters for 3D printing can dramatically affect the dynamic performance of components such as polymer spur gears. In this paper, the performance of 3D printed gears has been optimised using a machine learning process. A genetic algorithm (GA)–based artificial neural network (ANN) multi-parameter regression model was created. There were four print parameters considered in 3D printing process, i.e. printing temperature, printing speed, printing bed temperature and infill percentage. The parameter setting was generated by the Sobol sequence. Moreover, sensitivity analysis was carried out in this paper, and leave-one cross validation was applied to the genetic algorithm-based ANN which showed a relatively accurate performance in predictions and performance optimisation of 3D printed gears. Wear performance of 3D printed gears increased by 3 times after optimised parameter setting was applied during their manufacture

The Sphingosine-1-Phosphate/Sphingosine-1-Phosphate Receptor 2 Axis in Intestinal Epithelial Cells Regulates Intestinal Barrier Function During Intestinal Epithelial Cells–CD4+T-Cell Interactions

Background/Aims: Epithelial cells line the intestinal mucosa and form an important barrier for maintaining host health. This study aimed to explore the mechanism of the Sphingosine-1-phosphate (S1P)/Sphingosine-1-phosphate receptor 2 (S1PR2) pathway in intestinal epithelial cells (IECs) that participate in the intestinal barrier function. Methods: In this study, we constructed a knockout of the S1PR2 gene in mice, and Dextra sulfate sodium (DSS) was used to induce colitis. We isolated IECs from wild type (WT) and S1PR2–/– mice, and the endogenous expression of S1PR2 and Zonula occludens 1 (ZO-1) in IEC were detected by Western blot. Next, the major histocompatibility complex II (MHC-II) expression was analyzed by reverse transcription quantitative real-time (RT-qPCR) and flow cytometry. The in vivo and in vitro intestinal permeability were evaluated by serum fluorescein isothiocyanate (FITC) concentration. The tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interferon-γ (IFN-γ) levels in cell suspension were analyzed by enzyme-linked immuno sorbent assay (ELISA). A carboxyfluorescein diacetate succinimidyl ester (CFSE) assay was used to detect the T-cell proliferation in a co-culture system. Results: The intestinal mucosal barrier damage in S1PR2–/– mice was more severe than in the WT mice, and there were more CD4+T-cells in the colon tissue of DSS-treated S1PR2–/– mice. Either the mouse colon carcinoma cell line (CT26. WT) or the IECs upregulated MHC-II expression, which then promoted CD4+T-cell proliferation. The S1P/S1PR2 pathway controlled MHC-II expression to regulate CD4+T-cell proliferation via the extracellular signal-regulated kinase (ERK) pathway. In addition, the IFN-γ that was secreted by CD4+T-cells increased DSS-induced damage of intestinal epithelial cell barrier function. ZO-1 expression was increased by S1P in CT26.WT cells, while S1PR2 antagonist JTE-013 expression was downregulated. However, in CT26.WTsi-S1PR2 cells, S1P had no effect on ZO-1 expression. Conclusions: The S1P/S1PR2 axis in IECs mediated CD4+T-cell activation via the ERK pathway and MHC-II expression to regulate intestinal barrier function