• 제목/요약/키워드: Population heterogeneity

검색결과 137건 처리시간 0.023초

Insights into the Gut Microbiota of Freshwater Shrimp and Its Associations with the Surrounding Microbiota and Environmental Factors

  • Zhao, Yanting;Duan, Cuilan;Zhang, Xu-xiang;Chen, Huangen;Ren, Hongqiang;Yin, Ying;Ye, Lin
    • Journal of Microbiology and Biotechnology
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    • 제28권6호
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    • pp.946-956
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    • 2018
  • The gut microbiota of aquatic animals plays a crucial role in host health through nutrient acquisition and outcompetition of pathogens. In this study, on the basis of the high-throughput sequencing of 16S rRNA gene amplicons, we examined the bacterial communities in the gut of freshwater shrimp (Macrobrachium nipponense) and in their living environments (sediment and pond water) and analyzed the effects of abiotic and biotic factors on the shrimp gut bacterial communities. High bacterial heterogeneity was observed in the freshwater shrimp gut samples, and the result indicated that both the surrounding bacterial community and water quality factors (particularly dissolved oxygen and temperature) could affect the shrimp gut bacterial community. Despite the observed heterogeneity, 57 genera, constituting 38-99% of the total genera in each of the 40 shrimp gut samples, were identified as the main bacterial population in the gut of M. nipponense. In addition, a high diversity and abundance of lactic acid bacteria (26 genera), which could play significant roles in the digestion process in shrimp, were observed in the shrimp gut samples. Overall, this study provides insights into the gut bacterial communities of freshwater shrimp and basic information for shrimp farming regarding the application of probiotics and disease prevention.

Basic reproduction number of African swine fever in wild boars (Sus scrofa) and its spatiotemporal heterogeneity in South Korea

  • Lim, Jun-Sik;Kim, Eutteum;Ryu, Pan-Dong;Pak, Son-Il
    • Journal of Veterinary Science
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    • 제22권5호
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    • pp.71.1-71.12
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    • 2021
  • Background: African swine fever (ASF) is a hemorrhagic fever occurring in wild boars (Sus scrofa) and domestic pigs. The epidemic situation of ASF in South Korean wild boars has increased the risk of ASF in domestic pig farms. Although basic reproduction number (R0) can be applied for control policies, it is challenging to estimate the R0 for ASF in wild boars due to surveillance bias, lack of wild boar population data, and the effect of ASF-positive wild boar carcass on disease dynamics. Objectives: This study was undertaken to estimate the R0 of ASF in wild boars in South Korea, and subsequently analyze the spatiotemporal heterogeneity. Methods: We detected the local transmission clusters using the spatiotemporal clustering algorithm, which was modified to incorporate the effect of ASF-positive wild boar carcass. With the assumption of exponential growth, R0 was estimated for each cluster. The temporal change of the estimates and its association with the habitat suitability of wild boar were analyzed. Results: Totally, 22 local transmission clusters were detected, showing seasonal patterns occurring in winter and spring. Mean value of R0 of each cluster was 1.54. The estimates showed a temporal increasing trend and positive association with habitat suitability of wild boar. Conclusions: The disease dynamics among wild boars seems to have worsened over time. Thus, in areas with a high elevation and suitable for wild boars, practical methods need to be contrived to ratify the control policies for wild boars.

Motor imagery on upper extremity function for persons with stroke: a systematic review and meta-analysis

  • Lee, Dongsu;Hwang, Sujin
    • Physical Therapy Rehabilitation Science
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    • 제8권1호
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    • pp.52-59
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    • 2019
  • Objective: The purpose of this review was to investigate whether motor imagery training has an effect on the recovery of upper extremity function in individuals with hemiparetic stroke or not. Design: A systematic review and meta-analysis. Methods: PubMed and three other databases were searched up to December 18th, 2018 and randomized controlled trials (RCTs) evaluating motor imagery training on upper extremity function in persons with a diagnosis of hemiparetic stroke were included. This review selected the following information from each study: surname of the first author, published year, nation, population, intervention, therapeutic intensity of intervention, therapeutic comparison, outcome measures, additional therapy, summary of results, and descriptive statistics of outcome measures. Results: This review selected seventeen RCTs with 487 stroke survivors and the following intervention methods: six motor imagery training with additional therapeutic technology, two motor imagery training with additional modified constraint-induced therapy, four mirror therapy, and five motor imagery training. Ten RCTs were eligible for meta-analysis after systematic review. The motor imagery group were more effective than the control group based on the Fugl-Meyer assessment (3.43; 95% confidence interval [CI], 1.65 to 5.22; heterogeneity [$chi^2=8.03$, df=8, $I^2=0%$], test of overall effect Z=3.76; test for subgroup differences [$chi^2=2.56$, df=2, $I^2=21.8%$]) and the Action Research Arm Test (1.32; 95% CI, -8.12 to 10.76; heterogeneity [$Tau^2=70.74$, $chi^2=15.22$, df=3, $I^2=80%$], test of overall effect Z=3.76). Conclusions: The results of this review suggests that motor imagery shows positive effectiveness on improving upper extremity function in persons with hemiparetic stroke.

우리나라 이산화탄소 배출량 결정요인 분석: 횡단면 의존성과 계수 이질성을 고려하여 (Analysis of Determinants of Carbon Dioxide Emissions in Korea: Considering Cross-sectional Dependence and Heterogeneous Coefficient)

  • 김소연;류수열
    • 한국경제지리학회지
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    • 제24권4호
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    • pp.400-410
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    • 2021
  • 본 연구는 2000년부터 2019년까지 우리나라 16개 광역시·도의 패널자료를 활용하여 확장된 STIRPAT 모형을 통해 이산화탄소 배출량 결정요인을 분석하였다. 패널 데이터의 횡단면 의존성과 계수 이질성을 검정한 후, 이들 특성을 반영한 MG, CCEMG, AMG 추정법을 통해 분석하였다. AMG 추정법을 통해 분석한 결과를 살펴보면, 소득, 인구, 에너지 집약도의 계수가 양(+)의 부호로 통계적으로 유의하게 나타났으나, 도시화는 통계적으로 유의하지 않는 것으로 나타났다. 우리나라 이산화탄소 배출량의 감소는 에너지 효율의 증가와 지속가능한 경제성장을 통해 이루어질 수 있다. 따라서 이산화탄소 감축기술의 적극적인 개발로 저탄소 사회를 구축하고, 이와 함께 기술혁신을 통해 장기적으로 생산성 향상을 유발하여 지속가능한 경제성장에 기여할 수 있는 정책수립이 필요하다.

Experimental Infection of Different Tomato Genotypes with Tomato mosaic virus Led to a Low Viral Population Heterogeneity in the Capsid Protein Encoding Region

  • Sihelska, Nina;Vozarova, Zuzana;Predajna, Lukas;Soltys, Katarina;Hudcovicova, Martina;Mihalik, Daniel;Kraic, Jan;Mrkvova, Michaela;Kudela, Otakar;Glasa, Miroslav
    • The Plant Pathology Journal
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    • 제33권5호
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    • pp.508-513
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    • 2017
  • The complete genome sequence of a Slovak SL-1 isolate of Tomato mosaic virus (ToMV) was determined from the next generation sequencing (NGS) data, further confirming a limited sequence divergence in this tobamovirus species. Tomato genotypes Monalbo, Mobaci and Moperou, respectively carrying the susceptible tm-2 allele or the Tm-1 and Tm-2 resistant alleles, were tested for their susceptibility to ToMV SL-1. Although the three tomato genotypes accumulated ToMV SL-1 to similar amounts as judged by semiquantitative DAS-ELISA, they showed variations in the rate of infection and symptomatology. Possible differences in the intra-isolate variability and polymorphism between viral populations propagating in these tomato genotypes were evaluated by analysis of the capsid protein (CP) encoding region. Irrespective of genotype infected, the intra-isolate haplotype structure showed the presence of the same highly dominant CP sequence and the low level of population diversity (0.08-0.19%). Our results suggest that ToMV CP encoding sequence is relatively stable in the viral population during its replication in vivo and provides further demonstration that RNA viruses may show high sequence stability, probably as a result of purifying selection.

Functional PstI/RsaI Polymorphisms in the CYP2E1 Gene among South Indian Populations

  • Lakkakula, Saikrishna;Maram, Rajasekhar;Munirajan, Arasambattu Kannan;Pathapati, Ram Mohan;Visweswara, Subrahmanyam Bhattaram;Lakkakula, Bhaskar V.K.S.
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권1호
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    • pp.179-182
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    • 2013
  • Human cytochrome P4502E1 (CYP2E1) is a well-conserved xenobiotic-metabolizing enzyme expressed in liver, kidney, nasal mucosa, brain, lung, and other tissues. CYP2E1 is inducible by ethanol, acetone, and other low-molecular weight substrates and may mediate development of chemically-mediated cancers. CYP2E1 polymorphisms alter the transcriptional activity of the gene. This study was conducted in order to investigate the allele frequency variation in different populations of Andhra Pradesh. Two hundred and twelve subjects belonging to six populations were studied. Genotype and allele frequency were assessed through TaqMan allelic discrimination (rs6413419) and polymerase chain reaction-sequencing (-1295G>C and -1055C>T) after DNA isolation from peripheral leukocytes. The data were compared with other available world populations. The SNP rs6413419 is monomorphic in the present study, -1295G>C and -1055C>T are less polymorphic and followed Hardy-Weinberg equilibrium in all the populations studied. The -1295G>C and -1055C>T frequencies were similar and acted as surrogates in all the populations. Analysis of HapMap populations data revealed no significant LD between these markers in all the populations. Low frequency of $CYP2E1^*c2$ could be useful in the understanding of south Indian population gene composition, alcohol metabolism, and alcoholic liver disease development. However, screening of additional populations and further association studies are necessary. The heterogeneity of Indian population as evidenced by the different distribution of $CYP2E1^*c2$ may help in understanding the population genetic and evolutionary aspects of this gene.

Sex ratios and spatial structure of the dioecious tree Torreya nucifera in Jeju Island, Korea

  • Kang, Hye-Soon;Shin, Soo-Kyung
    • Journal of Ecology and Environment
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    • 제35권2호
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    • pp.111-122
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    • 2012
  • The sex ratio and spatial structure of different sexes are major components that affect the reproductive success and population persistence of dioecious plants. The differential reproductive costs between male and female plants are often believed to cause a biased sex ratio and spatial segregation of the sexes through slower growth and/or lower female survivorship. In this study, we examined the sex ratio and spatial structure of one population of $Torreya$ $nucifera$ trees in Jeju Island, Korea. We also tested the effects of the current tending actions in relation to tree vitality. At the population level, the sex ratio of the 2,861 trees was significantly biased toward males; however, it also showed considerable variation among different diameter at breast height classes and across habitats according to terrain level (from upper to lower). In 1999, before tree management (tending) began, among the ecological traits examined, only climber coverage correlated with tree vitality. Intensive tending such as climber removal since 1999 clearly enhanced the vitality of the majority of trees, but its effects were more conspicuous in medium-sized trees than in small ones, in upper terrain trees than those in other terrains, and in females than in males. Both male tree domination in small and large trees and tending effects on females are likely to reflect the effects of female reproductive costs regarding growth and/or survivorship. Spatial segregation between males and females was not observed in $T.$ $nucifera$. Habitat heterogeneity created by the forest's rocky ground and its implications regarding sex ratios and spatial structure require further studies.

목포 유달산에서의 나비 개체군 동태에 관한 연구 (Butterfly Population Dynamics at Mt, Yudal, Mokpo, Korea)

  • 기경자;최세웅
    • 환경생물
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    • 제22권1호
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    • pp.35-42
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    • 2004
  • 목포 유달산에서의 나비 종 구성과 개체군 변동을 알아보기 위하여 2001년 5월부터 2002년 4월까지 1년 동안 유달산을 4개의 지점으로 나누어 나비를 채집하였다. 그 결과 40종의 나비종이 분포하고 있는 것을 확인할 수 있었다. 각 지점별 나비 개체군 변동을 관찰한 결과 고. E 가 낮을수록 종 수와 개체군 수가 증가함을 볼 수 있었다. 조사기간 동안 월별 종 수 변동은 M-자형을 나타내는 반면 월별 개체수 변동은 8월에 가장 높은 피크를 보이는 곡선을 나타내었다. 종 수와 개체수 변동을 효과적으로 나타내는 풍부도 지수와 균등도 지수를 사용하여 조사지점 및 월별 변화를 살펴본 결과 두 지수는 서로 독립적이면서 약한 부정적인 상관관계를 나타내었다. 즉 풍부도 지수가 높은 경우 균등도 지수는 낮은 값을 나타내었다. 본 연구는 장기간의 나비 종의 개체수 및 종 수의 변동을 조사하기 위한 기초조사로써, 앞으로 이 지역에서 장기간의 나비 개체군 변동을 연구한다면 현재 지구적으로 문제가 되는 온난화 현상을 감지하거나, 유달산지역에서 나비 개체군을 위한 효과적인 서식지 관리 방법도 찾을 수 있을 것으로 기대한다.

Refining and Validating a Two-stage and Web-based Cancer Risk Assessment Tool for Village Doctors in China

  • Shen, Xing-Rong;Chai, Jing;Feng, Rui;Liu, Tong-Zhu;Tong, Gui-Xian;Cheng, Jing;Li, Kai-Chun;Xie, Shao-Yu;Shi, Yong;Wang, De-Bin
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권24호
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    • pp.10683-10690
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    • 2015
  • The big gap between efficacy of population level prevention and expectations due to heterogeneity and complexity of cancer etiologic factors calls for selective yet personalized interventions based on effective risk assessment. This paper documents our research protocol aimed at refining and validating a two-stage and web-based cancer risk assessment tool, from a tentative one in use by an ongoing project, capable of identifying individuals at elevated risk for one or more types of the 80% leading cancers in rural China with adequate sensitivity and specificity and featuring low cost, easy application and cultural and technical sensitivity for farmers and village doctors. The protocol adopted a modified population-based case control design using 72, 000 non-patients as controls, 2, 200 cancer patients as cases, and another 600 patients as cases for external validation. Factors taken into account comprised 8 domains including diet and nutrition, risk behaviors, family history, precancerous diseases, related medical procedures, exposure to environment hazards, mood and feelings, physical activities and anthropologic and biologic factors. Modeling stresses explored various methodologies like empirical analysis, logistic regression, neuro-network analysis, decision theory and both internal and external validation using concordance statistics, predictive values, etc..

Viral characteristics of plaque variants of porcine reproductive and respiratory syndrome virus

  • Park, Bong-kyun;Molitor, Thomas W.;Joo, Han-soo
    • 대한수의학회지
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    • 제39권4호
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    • pp.751-759
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    • 1999
  • Plaque characteristics of porcine reproductive and respiratory syndrome (PRRS) virus isolates were examined using MARC-145 line cells. The plaque morphology of PRRS virus isolates was variable in size and heterogenic in population. Upon serial passages of the PRRS virus isolates on MARC-145 tells, heterogeneity was maintained but numbers of the large plaque size virus were increased with certain isolates. A PRRS virus isolate with variable plaque sizes was subcloned into 2 populations : small plaque ($H_S$) and large plaque ($H_L$) viruses. Growth kinetics of the subclones were then determined in MARC-145 cells, and production of the structural polypeptides was analyzed by SDS-PAGE. In a comparison of the growth kinetics, the $H_S$ virus showed higher infectivity titers during the first 48 hours but slower to reach the peak titier than $H_L$ virus did. In a nucleotide sequence comparison, differences of 4 nucleotides in open reading frames 5-6 gene were found between $H_S$ and $H_L$ viruses. Both the $H_S$ and $H_L$ clones produced 5 polypeptide bands with molecular weights of 15, 19, 26, 36 and 42 kD. The 5 bands were detected at 48 hours postinoculation (PI) with antisera to $H_L$ and another large plaque virus ($W_L$) and at 72 hours PI with $H_S$ virus antiserum. The present results demonstrate differences of biologic and molecular characteristics between the two PRRS virus plaque clones.

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