316 research outputs found

    Spatial Distribution and Sampling Technique for Aphis glycines Matsumura

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    The spatial distribution of Aphis glycines Matsumura was studied. All sets of samples exhibited aggregated patterns of spatial distribution, but did not fit Poisson, Neymann (n=0?4 and ?), Poisson-binomial and compound Poisson distributions. Of 11 sets of samples tested, 10 sets fitted the negative binomial distribution; only 1 set did not fit. The fundamental components of the spatial distributions of Aphis glycines are aggregated distribution of individual populations; the degrees of aggregation increase with the population densities. The spatial distribution parameters ( ? m , C? , ? I , x m ? ,?,? ) of the soybean aphids and species aggregation average degree ( ? ) were analyzed, the reason of aggregation patterns of the aphids was discussed, and the relation between the average sizes of the individual population and its average densities was predicted. The theoretical sizes of sampling and sequential sampling plans of fixed levels with precision were determined by utilizing estimated variance/mean relationship obtained from Taylorā€™s power law regression. The theoretical size of sampling is 2 0.64 5.364 D x n ? ? and the stop line of fixed-precision-level sequential sampling is 3.125 0.563 * 13.8 D n T n ? .Originating text in Chinese.Citation: Su, Jianya, Hao, Kangshan, Shi, Xiaoling. (1996). Spatial Distribution and Sampling Technique for Aphis glycines Matsumura. Journal of Nanjing Agricultural University, 19(3), 55-58

    Microgrid Stability Controller Based on Adaptive Robust Total SMC

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    This paper presents a microgrid stability controller (MSC) in order to provide existing distributed generation units (DGs) the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding-mode control (ARTSMC) system for the MSC. It is proved that the ARTSMC system is insensitive to parametric uncertainties and external disturbances. The MSC provides fast dynamic response and robustness to the microgrid. When the system is operating in grid-connected mode, it is able to improve the controllability of the exchanged power between the microgrid and the utility grid, while smoothing the DGsā€™ output power. When the microgrid is operating in islanded mode, it provides voltage and frequency support, while guaranteeing seamless transition between the two operation modes. Simulation and experimental results show the effectiveness of the proposed approach

    Relative Entropy in CFT

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    By using Araki's relative entropy, Lieb's convexity and the theory of singular integrals, we compute the mutual information associated with free fermions, and we deduce many results about entropies for chiral CFT's which are embedded into free fermions, and their extensions. Such relative entropies in CFT are here computed explicitly for the first time in a mathematical rigorous way. Our results agree with previous computations by physicists based on heuristic arguments; in addition we uncover a surprising connection with the theory of subfactors, in particular by showing that a certain duality, which is argued to be true on physical grounds, is in fact violated if the global dimension of the conformal net is greater than 1.1.Comment: 31 page

    Molecular characterization of a mosaic locus in the genome of 'Candidatus Liberibacter asiaticus'

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    <p>Abstract</p> <p>Background</p> <p>Huanglongbing (HLB) is a highly destructive disease of citrus production worldwide. '<it>Candidatus </it>Liberibacter asiaticus', an unculturable alpha proteobacterium, is a putative pathogen of HLB. Information about the biology and strain diversity of '<it>Ca</it>. L. asiaticus' is currently limited, inhibiting the scope of HLB research and control.</p> <p>Results</p> <p>A genomic region (CLIBASIA_05640 to CLIBASIA_05650) of '<it>Ca</it>. L. asiaticus' showing hyper-sequence variation or locus mosaicism was identified and investigated using 262 bacterial strains (188 from China and 74 from Florida). Based on the characteristic electrophoretic profiles of PCR amplicons generated by a specific primer set, eight electrophoretic types (E-types) were identified, six E-types (A, B, C, D, E, and F) in China and four E-types (A, C, G, and H) in Florida. The '<it>Ca</it>. L. asiaticus' strains from China consisted predominately of E-type A (71.3%) and E-type B (19.7%). In contrast, the '<it>Ca</it>. L. asiaticus' strains from Florida was predominated by E-type G (82.4%). Diversity of '<it>Ca</it>. L. asiaticus' in China was also evidenced. Strains from the high altitude Yunnan Province consisted of five E-types with E-type B being the majority (62.8%), whereas strains from the low altitude coastal Guangdong Province consisted of only two E-types with E-type A as the majority (97.0%). Sequence analyses revealed that variation of DNA amplicons was due to insertion/deletion events at CLIBASIA_05650 and the downstream intergenic region.</p> <p>Conclusions</p> <p>This study demonstrated the genomic mosaicism of '<it>Ca</it>. L. asiaticus' resulted from active DNA insertion/deletion activities. Analyses of strain variation depicted the significant inter- and intra-continent diversity of '<it>Ca</it>. L. asiaticus'.</p

    A 2-step penalized regression method for family-based next-generation sequencing association studies

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    Large-scale genetic studies are often composed of related participants, and utilizing familial relationships can be cumbersome and computationally challenging. We present an approach to efficiently handle sequencing data from complex pedigrees that incorporates information from rare variants as well as common variants. Our method employs a 2-step procedure that sequentially regresses out correlation from familial relatedness and then uses the resulting phenotypic residuals in a penalized regression framework to test for associations with variants within genetic units. The operating characteristics of this approach are detailed using simulation data based on a large, multigenerational cohort

    Ethnic differences and heritability of blood pressure circadian rhythm in African and European American youth and young adults

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    Background: The aim of this study was to investigate whether blood pressure (BP) circadian rhythm in African Americans differed from that in European Americans. We further examined the genetic and/or environmental sources of variances of the BP circadian rhythm parameters and the extent to which they depend on ethnicity or sex. Method: Quantification of BP circadian rhythm was obtained using Fourier transformation from the ambulatory BP monitoring data of 760 individuals (mean age, 17.2 +/- 3.3; 322 twin pairs and 116 singletons; 351 African Americans). Results: BP circadian rhythm showed a clear difference by ethnic group with African Americans having a lower amplitude (P = 1.5e-08), a lower percentage rhythm (P = 2.8e-11), a higher MESOR (P = 2.5e-05) and being more likely not to display circadian rhythm (P = 0.002) or not in phase (P = 0.003). Familial aggregation was identified for amplitude, percentage rhythm and acrophase with genetic factors and common environmental factors together accounting for 23 to 33% of the total variance of these BP circadian rhythm parameters. Unique environmental factors were the largest contributor explaining up to 67--77% of the total variance of these parameters. No sex or ethnicity difference in the variance components of BP circadian rhythm was observed. Conclusion: This study suggests that ethnic differences in BP circadian rhythm already exist in youth with African Americans having a dampened circadian rhythm and better BP circadian rhythm may be achieved by changes in environmental factors

    Decreased heritability and emergence of novel genetic effects on pulse wave velocity from youth to young adulthood

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    Increased arterial stiffness measured by pulse wave velocity (PWV) is an important parameter in the assessment of cardiovascular risk. Our previous longitudinal study has demonstrated that carotid-distal PWV showed reasonable stability throughout youth and young adulthood. This stability might be driven by genetic factors that are expressed consistently over time. We aimed to illustrate the relative contributions of genetic and environmental factors to the stability of carotid-distal PWV from youth to young adulthood. We also examined potential ethnic differences. For this purpose, carotid-distal PWV was measured twice in 497 European American (EA) and African American (AA) twins, with an average interval time of 3 years. Twin modelling on PWV showed that heritability decreased over time (62-35%), with the nonshared environmental influences becoming larger. There was no correlation between the nonshared environmental factors on PWV measured at visit 1 and visit 2, with the phenotypic tracking correlation (r=0.32) completely explained by shared genetic factors over time. Novel genetic influences were identified accounting for a significant part of the variance (19%) at the second measurement occasion. There was no evidence for ethnic differences. In summary, novel genetic effects appear during development into young adulthood and account for a considerable part of the variation in PWV. Environmental influences become larger with age for PWV
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