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1,350 results on '"Yang, Xiaorong"'

14. Functional-Coefficient Quantile Regression for Panel Data with Latent Group Structure

Author

Yang, Xiaorong, Chen, Jia, Li, Degui, and Li, Runze

Subjects
Economics - Econometrics, Statistics - Methodology
Abstract

This paper considers estimating functional-coefficient models in panel quantile regression with individual effects, allowing the cross-sectional and temporal dependence for large panel observations. A latent group structure is imposed on the heterogenous quantile regression models so that the number of nonparametric functional coefficients to be estimated can be reduced considerably. With the preliminary local linear quantile estimates of the subject-specific functional coefficients, a classic agglomerative clustering algorithm is used to estimate the unknown group structure and an easy-to-implement ratio criterion is proposed to determine the group number. The estimated group number and structure are shown to be consistent. Furthermore, a post-grouping local linear smoothing method is introduced to estimate the group-specific functional coefficients, and the relevant asymptotic normal distribution theory is derived with a normalisation rate comparable to that in the literature. The developed methodologies and theory are verified through a simulation study and showcased with an application to house price data from UK local authority districts, which reveals different homogeneity structures at different quantile levels.

Published
2023

26. Monitoring and analysis of STEC in cow manure from a dairy farm and retail fresh beef around Chengdu City

Author

LYU Hong, LEI Gaopeng, LIU Li, XIAO Tao, and YANG Xiaorong

Subjects
shiga toxin producing escherichia coli, drug resistance, serotype, virulence gene, Food processing and manufacture, TP368-456, Nutrition. Foods and food supply, TX341-641
Abstract

ObjectiveTo understand the carrying status and strain characteristics of STEC strains in cattle and beef in the local area， provide scientific basis for evaluating the STEC pollution status， infection risk， prevention and control strategies in the region， the Shiga toxin producing Escherichia coli （STEC） in the feces of calves and adult cows and feeding environment in a dairy farm around Chengdu， as well as fresh beef from vegetable markets and supermarkets for three years were continuously monitored.MethodsSTEC using fluorescence quantitative PCR method was identified， and drug sensitivity testing using micro broth dilution method was conducted. After sequencing the entire genome of the isolated strain， the MLST type， strain type， serotyping， and virulence gene information were obtained on the EnteroBase database. The stx subtype information was compared using the Abricate software. Perform cgMLST clustering analysis was used by BioNumerics 7.6 software.ResultsFrom 2019 to 2021， a total of 247 cow manure and environmental samples were collected from dairy farms， and 25 STEC strains were isolated， with a detection rate of 10.12%. 294 fresh beef samples were collected and 32 STECs were isolated， with a detection rate of 10.88%. A total of 57 STEC strains were isolated. The STEC strain had the highest resistance rate to ampicillin， reaching 42.11%（24/57）， followed by cefotaxime and cefazolin at 38.60%（22/57）. Multiple resistant strains accounted for 35.09%（20/57）. A total of 30 serotypes were isolated from 57 STEC strains， among which the serotypes that can cause outbreaks include O26：H11， O103：H25， and O145：H12. Through virulence gene analysis， it was found that subtypes with pathogenic risk included stx2a， stx2c， stx2d， stx2e， stx2g， stx2k， as well as eae-STEC and STEC/ETEC heterozygous strains.ConclusionThe pollution of STEC in cow manure from dairy farms and fresh beef from vegetable markets continued to exist from 2019 to 2021. The detection rate of calf feces was 21.43%， which was higher than that of adult cow feces by 0.91%. The STEC detection rate of fresh beef in vegetable markets is significantly higher than that in supermarkets. The drug resistance of strains isolated from cow manure is more severe than that of strains isolated from beef. Some isolated strains have stronger pathogenicity due to carrying strong virulence genes or other pathogenic related genes.

Published
2023
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49. Non-invasive early detection of cancer four years before conventional diagnosis using a blood test.

Author

Chen, Xingdong, Gole, Jeffrey, Gore, Athurva, He, Qiye, Lu, Ming, Min, Jun, Yuan, Ziyu, Yang, Xiaorong, Jiang, Yanfeng, Zhang, Tiejun, Suo, Chen, Li, Xiaojie, Cheng, Lei, Zhang, Zhenhua, Niu, Hongyu, Li, Zhe, Xie, Zhen, Shi, Han, Zhang, Xiang, Fan, Min, Wang, Xiaofeng, Yang, Yajun, Dang, Justin, McConnell, Catie, Zhang, Juan, Wang, Jiucun, Yu, Shunzhang, Ye, Weimin, Gao, Yuan, Zhang, Kun, Liu, Rui, and Jin, Li

Subjects
Humans, Neoplasms, Genetic Markers, Sensitivity and Specificity, Longitudinal Studies, Reproducibility of Results, DNA Methylation, Adult, Aged, Aged, 80 and over, Middle Aged, China, Female, Male, Early Detection of Cancer, Young Adult, Epigenomics, High-Throughput Nucleotide Sequencing, Healthy Volunteers, Biomarkers, Tumor, Circulating Tumor DNA
Abstract

Early detection has the potential to reduce cancer mortality, but an effective screening test must demonstrate asymptomatic cancer detection years before conventional diagnosis in a longitudinal study. In the Taizhou Longitudinal Study (TZL), 123,115 healthy subjects provided plasma samples for long-term storage and were then monitored for cancer occurrence. Here we report the preliminary results of PanSeer, a noninvasive blood test based on circulating tumor DNA methylation, on TZL plasma samples from 605 asymptomatic individuals, 191 of whom were later diagnosed with stomach, esophageal, colorectal, lung or liver cancer within four years of blood draw. We also assay plasma samples from an additional 223 cancer patients, plus 200 primary tumor and normal tissues. We show that PanSeer detects five common types of cancer in 88% (95% CI: 80-93%) of post-diagnosis patients with a specificity of 96% (95% CI: 93-98%), We also demonstrate that PanSeer detects cancer in 95% (95% CI: 89-98%) of asymptomatic individuals who were later diagnosed, though future longitudinal studies are required to confirm this result. These results demonstrate that cancer can be non-invasively detected up to four years before current standard of care.

Published
2020

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