Objective Based on the transcriptome data of Scolopendra subspinipes mutilans L.Koch,SSR primers were designed and developed to evaluate the genetic diversity and analyze the population structure of the germplasm resources of S.mutilans,which can provide a theoretical basis for the development and utilization of the germplasm resources of S.mutilans.Methods We collected 301 samples of S.mutilans from major production areas,and analyzed the population genetic diversity and population structure of the germplasm resources of S.mutilans using 18 pairs of highly polymorphic SSR primers after screening.Results A total of 142 alleles were amplified by 18 primer pairs across all samples,with an average of 7.89 alleles amplified per locus.The mean of observed heterozygosity(HO)of the 18 populations was 0.39,the mean of expected heterozygosity(HE)was 0.46,the mean of polymorphism information content(PIC)was 0.41,the mean of Nei's gene diversity index(H)was 0.46,and the mean of Shannon information index(I)was 0.81.The results showed that the wild resources of S.mutilans collected in this study had a high level of genetic diversity,Four populations in Anhui and Zhejiang had higher genetic diversity than populations in Hubei.Molecular analysis of variance(AMOVA)of the population showed that most of the genetic variation in the materials of this study mainly occurred within populations.The STRUCTURE analysis of germplasm resources showed that all germplasm could be divided into four populations.Conclusion This study showed that the natural population of S.mutilans possesses high genetic diversity with high genetic variation and is better adapted to changes in the environment.Our results provided a research basis for the rational utilization of the germplasm resources of S.mutilans and the selection and breeding of superior varieties.

Objective Based on the transcriptome data of Scolopendra subspinipes mutilans L.Koch,SSR primers were designed and developed to evaluate the genetic diversity and analyze the population structure of the germplasm resources of S.mutilans,which can provide a theoretical basis for the development and utilization of the germplasm resources of S.mutilans.Methods We collected 301 samples of S.mutilans from major production areas,and analyzed the population genetic diversity and population structure of the germplasm resources of S.mutilans using 18 pairs of highly polymorphic SSR primers after screening.Results A total of 142 alleles were amplified by 18 primer pairs across all samples,with an average of 7.89 alleles amplified per locus.The mean of observed heterozygosity(HO)of the 18 populations was 0.39,the mean of expected heterozygosity(HE)was 0.46,the mean of polymorphism information content(PIC)was 0.41,the mean of Nei's gene diversity index(H)was 0.46,and the mean of Shannon information index(I)was 0.81.The results showed that the wild resources of S.mutilans collected in this study had a high level of genetic diversity,Four populations in Anhui and Zhejiang had higher genetic diversity than populations in Hubei.Molecular analysis of variance(AMOVA)of the population showed that most of the genetic variation in the materials of this study mainly occurred within populations.The STRUCTURE analysis of germplasm resources showed that all germplasm could be divided into four populations.Conclusion This study showed that the natural population of S.mutilans possesses high genetic diversity with high genetic variation and is better adapted to changes in the environment.Our results provided a research basis for the rational utilization of the germplasm resources of S.mutilans and the selection and breeding of superior varieties.

Objective To investigate the effects of noise from the subway cars on the preferred listening volumes using different kinds of earphones.Methods A total of 75 subjects with normal hearing were investigated to listen the same song wearing 4 kinds of earphones: insert earphones, intra-concha earphones, supra-concha earphones, and circumaural earphones, in the semi-anechoic background and inside the Line 7 subway-cars of the Beijing subway (the mean of LAeq,1s is 80.3 dB A and then selected personally preferred listening volumes.The effects of noise in the subway cars and earphone types on the preferred listening volumes were then analyzed.Results Inside subway-cars, the preferred listening levels using insert earphones, intra-concha earphones, supra-concha earphones, circumaural earphones were 76.6±4.7, 84.3±5.0, 82.3±4.2, and 80.8±4.2 dB A, respectively.The levels were respectively 65.5±6.8, 71.9±7.1, 69.5±7.5, 67.9±7.3 dB A for those in the semi-anechoic background.The preferred listening levels increase more than 10 dB averagely when stepped into noisy subway-cars background from silent background.According to the threshold levels stipulated in the WHO, to avoid hearing impairment, the daily noise exposure duration should not exceed 134 mins when exposed to subway-cars noise and the duration should not exceed 315, 54, 85, and 120 mins respectively when wearing those 4 kinds of earphones in subway-cars.Conclusion The noise and earphones types have great effects on the preferred listening volumes.The noise exposure levels in the ear canal wearing earphones with good sound insulation and listening at highly increased volume may be lower than that without earphones.