67 research outputs found

    Temporal, spatial, and socioeconomic dynamics in social media thematic emphases during Typhoon Mangkhut

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    Disaster-related social media data often consist of several themes, and each theme allows people to understand and communicate from a certain perspective. It is necessary to take into consideration the dynamics of thematic emphases on social media in order to understand the nature of such data and to use them appropriately. This paper proposes a framework to analyze the temporal, spatial, and socioeconomic disparities in thematic emphases on social media during Typhoon Mangkhut. First, the themes were identified through a latent Dirichlet allocation model during Typhoon Mangkhut. Then, we adopted a quantitative method of indexing the themes to represent the dynamics of the thematic emphases. Spearman correlation analyses between the index and eight socioeconomic variables were conducted to identify the socioeconomic disparities in thematic emphases. The main research findings are revealing. From the perspective of time evolution, Theme 1 (general response) and Theme 2 (urban transportation) hold the principal position throughout the disaster. In the early hours of the disaster, Theme 3 (typhoon status and impact) was the most popular theme, but its popularity fell sharply soon after. From the perspective of spatial distribution, people in severely affected areas were more concerned about urban transportation (Theme 2), while people in moderately affected areas were more concerned about typhoon status and impact (Theme 3) and animals and humorous news (Theme 4). The results of the correlation analyses show that there are differences in thematic emphases across disparate socioeconomic groups. Women preferred to post about typhoon status and impact (Theme 3) and animals and humorous news (Theme 4), while people with higher income paid less attention to these two themes during Typhoon Mangkhut. These findings can help government agencies and other stakeholders address public needs effectively and accurately in disaster responses

    Neural Dependencies Emerging from Learning Massive Categories

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    This work presents two astonishing findings on neural networks learned for large-scale image classification. 1) Given a well-trained model, the logits predicted for some category can be directly obtained by linearly combining the predictions of a few other categories, which we call \textbf{neural dependency}. 2) Neural dependencies exist not only within a single model, but even between two independently learned models, regardless of their architectures. Towards a theoretical analysis of such phenomena, we demonstrate that identifying neural dependencies is equivalent to solving the Covariance Lasso (CovLasso) regression problem proposed in this paper. Through investigating the properties of the problem solution, we confirm that neural dependency is guaranteed by a redundant logit covariance matrix, which condition is easily met given massive categories, and that neural dependency is highly sparse, implying that one category correlates to only a few others. We further empirically show the potential of neural dependencies in understanding internal data correlations, generalizing models to unseen categories, and improving model robustness with a dependency-derived regularizer. Code for this work will be made publicly available

    Integrated Sensing and Communications: Recent Advances and Ten Open Challenges

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    It is anticipated that integrated sensing and communications (ISAC) would be one of the key enablers of next-generation wireless networks (such as beyond 5G (B5G) and 6G) for supporting a variety of emerging applications. In this paper, we provide a comprehensive review of the recent advances in ISAC systems, with a particular focus on their foundations, system design, networking aspects and ISAC applications. Furthermore, we discuss the corresponding open questions of the above that emerged in each issue. Hence, we commence with the information theory of sensing and communications (S&\&C), followed by the information-theoretic limits of ISAC systems by shedding light on the fundamental performance metrics. Next, we discuss their clock synchronization and phase offset problems, the associated Pareto-optimal signaling strategies, as well as the associated super-resolution ISAC system design. Moreover, we envision that ISAC ushers in a paradigm shift for the future cellular networks relying on network sensing, transforming the classic cellular architecture, cross-layer resource management methods, and transmission protocols. In ISAC applications, we further highlight the security and privacy issues of wireless sensing. Finally, we close by studying the recent advances in a representative ISAC use case, namely the multi-object multi-task (MOMT) recognition problem using wireless signals.Comment: 26 pages, 22 figures, resubmitted to IEEE Journal. Appreciation for the outstanding contributions of coauthors in the paper

    Streptococcus suis Sequence Type 7 Outbreak, Sichuan, China

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    An outbreak of Streptococcus suis serotype 2 emerged in the summer of 2005 in Sichuan Province, and sporadic infections occurred in 4 additional provinces of China. In total, 99 S. suis strains were isolated and analyzed in this study: 88 isolates from human patients and 11 from diseased pigs. We defined 98 of 99 isolates as pulse type I by using pulsed-field gel electrophoresis analysis of SmaI-digested chromosomal DNA. Furthermore, multilocus sequence typing classified 97 of 98 members of the pulse type I in the same sequence type (ST), ST-7. Isolates of ST-7 were more toxic to peripheral blood mononuclear cells than ST-1 strains. S. suis ST-7, the causative agent, was a single-locus variant of ST-1 with increased virulence. These findings strongly suggest that ST-7 is an emerging, highly virulent S. suis clone that caused the largest S. suis outbreak ever described

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    The Effect of Muscle-Regulatory Factor Genes and Satellite Cell Response to Recombinant Hsp70 Protein on Megalobrama amblycephala Skeletal Muscle

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    Hsp70 (70-kDa heat shock protein) plays a key regulatory role in muscle development. In order to evaluate whether recombinant Hsp70 protein (rMaHsp70) of M. amblycephala could affect muscle growth by inducing the expression of Myogenin (MyoG), Myogenic Differentiation Antigen (MyoD), Myogenic factor 5 (Myf5), myogenic regulatory factor 4 (MRF4) and myostatin (MSTN) in muscle, Hsp70 was injected intraperitoneally (IP) at two concentrations: 1.0 mg/mL and 3.4 mg/mL. The mRNA and protein levels of the transcription factor Pax-7 and the protein Hsp70 initially increased, then as concentration levels of injected recombinant M. amblycephala Hsp70 protein rMaHsp70 further increased, the protein Hsp70 decreased. In order to investigate the relationship between muscle hyperplasia, hypertrophy and satellite cell growth following rMaHsp70 administration, the number of satellite cells were analyzed and revealed that the numbers of satellite cells in low concentration group (1 mg/mL) was predominantly higher than in the other concentration groups in both red and white muscle. These results suggest that low concentrations of rMaHsp70 could decrease muscle-related gene expression and increase the number of satellite cells. Our research will be helpful in adapting Hsp70 as a feed additive to enhance M. amblycephala growth

    Molecular Characterization and Possible Immune Function of Two Members of Interleukin Family from Trachinotus ovatus

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    Interleukins (ILs) are a group of cytokines which play a core regulatory role in the immune system. In the present study, two members of the IL family, IL7 and IL8, were detected in Trachinotus ovatus. IL7 and IL8 cDNAs of T. ovatus consist of a 492 bp and 300 bp ORF (open reading frame) encoding a polypeptide of 163 and 99 amino acids, respectively. Multiple sequence alignment revealed that IL7 and IL8 contain characteristic arrangements of several conserved cysteine residues, which in T. ovatus are in positions 20, 57, 67, 105, 140, 152 and 35, 37, 61, 78, respectively. The phylogenetic tree showed that all ILs fell into four categories. Moreover, IL7 and IL8 mRNA of T. ovatus were constitutively expressed at different levels in all examined tissues, except muscle. Transcripts of IL7 were mainly expressed in liver, intestine, kidney, stomach, and fin, while transcripts of IL8 were highly detected in the eye, liver, kidney, and intestine of healthy fish. After Photobacterium damselae innoculation, mRNA levels of IL7 were higher than IL8 in the spleen and intestine, however, mRNA expression levels of IL7 were lower than IL8 in kidney 3 h post-injection. These results suggest that the two IL molecules play an important role in the inflammatory response of T. ovatus
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