Global Dynamics and Applications of an Epidemiological Model for Hepatitis C Virus Transmission in China

An epidemiological model is proposed and studied to understand the transmission dynamics and prevalence of HCV infection in China. Theoretical analysis indicates that the basic reproduction number R0 provides a threshold value determining whether the disease dies out or not. Two Lyapunov functions are constructed to prove the global asymptotic stability of the disease-free and the endemic equilibria, respectively. Based on data reported by the National Health and Family Planning Commission of China, the basic reproduction number is estimated as approximately R0=1.9897, which is much less than that for the model when a treatment strategy is not considered. An ever-increasing HCV infection is predicted in the near future. Numerical simulations, performed to investigate the potential effect of antiviral treatment, show that increasing the treatment cure rate and enlarging the treatment rate for patients at the chronic stage remain effective in reducing the number of new infections and the equilibrium prevalence. The finding suggests that treatment measures are significantly beneficial for disease control in terms of reducing new infections and, in particular, more attention should be paid to treatment for patients at the chronic stage

A Knowledge-Enhanced Recommendation Model with Attribute-Level Co-Attention

Deep neural networks (DNNs) have been widely employed in recommender systems including incorporating attention mechanism for performance improvement. However, most of existing attention-based models only apply item-level attention on user side, restricting the further enhancement of recommendation performance. In this paper, we propose a knowledge-enhanced recommendation model ACAM, which incorporates item attributes distilled from knowledge graphs (KGs) as side information, and is built with a co-attention mechanism on attribute-level to achieve performance gains. Specifically, each user and item in ACAM are represented by a set of attribute embeddings at first. Then, user representations and item representations are augmented simultaneously through capturing the correlations between different attributes by a co-attention module. Our extensive experiments over two realistic datasets show that the user representations and item representations augmented by attribute-level co-attention gain ACAM's superiority over the state-of-the-art deep models

4K4D: Real-Time 4D View Synthesis at 4K Resolution

This paper targets high-fidelity and real-time view synthesis of dynamic 3D scenes at 4K resolution. Recently, some methods on dynamic view synthesis have shown impressive rendering quality. However, their speed is still limited when rendering high-resolution images. To overcome this problem, we propose 4K4D, a 4D point cloud representation that supports hardware rasterization and enables unprecedented rendering speed. Our representation is built on a 4D feature grid so that the points are naturally regularized and can be robustly optimized. In addition, we design a novel hybrid appearance model that significantly boosts the rendering quality while preserving efficiency. Moreover, we develop a differentiable depth peeling algorithm to effectively learn the proposed model from RGB videos. Experiments show that our representation can be rendered at over 400 FPS on the DNA-Rendering dataset at 1080p resolution and 80 FPS on the ENeRF-Outdoor dataset at 4K resolution using an RTX 4090 GPU, which is 30x faster than previous methods and achieves the state-of-the-art rendering quality. Our project page is available at https://zju3dv.github.io/4k4d/.Comment: Project Page: https://zju3dv.github.io/4k4

Preferential regeneration of photoreceptor from Müller glia after retinal degeneration in adult rat

AbstractTo determine whether photoreceptor degeneration can stimulate Müller glia to transdifferentiate into neurons in adult mammalian retina, N-methyl-N-nitrosourea (MNU) was injected to induce complete loss of photoreceptors. Following MNU administration, Müller glia underwent reactive gliosis characterized by up-regulation of glial fibrillar acidic protein and nestin, and initiated proliferation through the cyclin D1 and D3 related pathways. Some Müller glia-derived cells were induced to express rhodopsin exclusively. These rhodopsin-positive cells exhibited synaptophysin around them, suggesting possible formation of synapses. After transplanted in to damaged retina, Müller glia migrated, grafted in host retina and produced rhodopsin. These results suggest that degeneration may promote preferential differentiation of Müller glia to photoreceptors and provide a potential therapeutic strategy for retinal degenerative diseases

Oviposition sequence of non-pollinating fig wasps associated with Ficus benjamina in China

Fig-fig wasp mutualisms are exploited by non-pollinating fig wasps (NPFWs). In most cases, NPFWs oviposit into ovaries of female flowers from outside syconia. In this study, the oviposition sequence of externally ovipositing non-pollinating fig wasps associated with Ficus benjamina were studied by direct observation, yellow sticky board and manipulation experiments in Xishuangbanna, southwest of China. The results showed that (i) Different genera of wasps showed a temporal partition in oviposition sequence among NPFWs. Acophila, Sycobia and Walkerella wasps colonized syconia in pre-female phase, while Micronisa, Philotrypesis and Sycoscapter oviposited in the interfloral phase. Further, NPFWs of the same genus also showed difference ovposition period. (ii) Different genera of wasps exhibited various strategies of resource exploitation. Acophila, Sycobia and Walkerella wasps were gallers, while Philotrypesis wasps should be inquiline. However, only the galler species Walkerella sp.2 had significant negative effective on pollinator and seed