127 research outputs found

    Cuatro nuevas especies de Pycnophyes (Kinorhyncha: Homalorhagida) de Corea y el mar del este de China

    Get PDF
    Four new species of Pycnophyes are described from Korean waters and the East China Sea. Pycnophyes pardosi n. sp. is distinguished from other congeners by the presence of a single paradorsal seta on segments 2-8 and a pair on segment 9, combined with the presence of longitudinal cuticular thickenings on the dorsal and ventral sides of segment 10. Pycnophyes chalgap n. sp. is easily distinguished by the shape of its midsternal plate with the rounded posterior margin, extending beyond and overlapping half of the following segment. Pycnophyes cristatus n. sp. is recognized by its lack of ventromedial setae on segments 3-6 combined with the presence of pointed middorsal processes that turn progressively longer towards the posterior segments from segment 6. The process on segment 10 is conspicuously long, extending beyond the posterior margin of segment 11. Pycnophyes smaug n. sp. is distinguished by its general scarcity of setae which, with the exception of those in lateroventral positions, only appear in laterodorsal positions on segments 2 and 9 and in ventromedial position on segment 9. The description of four additional species brings the total number of valid kinorhynch species around the Korean Peninsula up to 26.Se describen cuatro nuevas especies de aguas coreanas y del este del mar de China. Pycnophyes pardosi n. sp. se distingue de las demás especies por la presencia de una única seda paradorsal en los segmentos 2-8 y un par en el segmento 9, combinado con la presencia de engrosamientos cuticulares longitudinales en el lado dorsal y ventral del segmento 10. Pycnophyes chalgap n. sp. es fácilmente distinguible por la forma de su placa medioesternal con el margen posterior redondeado, sobrepasando y solapando la mitad anterior del siguiente segmento. Pycnophyes cristatus n. sp. es reconocible por la ausencia de sedas ventromediales en los segmentos 3-6 combinado con la presencia de salientes mediodorsales puntiagudos que a partir del segmento 6 se vuelven progresivamente más largos hacia los segmentos posteriores. El saliente del segmento 10 es llamativamente largo, extendiéndose más allá del margen posterior del segmento 11. Pycnophyes smaug n. sp. se distingue por su carencia general de sedas que, aparte de las lateroventrales, solo aparecen en posición laterodorsal en los segmentos 2 y 9, y en posición ventromedial en el segmento 9. La descripción de las cuatro especies aumenta hasta 26 el número total de especies válidas de kinorrincos entorno a la península coreana

    Construction cost estimation using a case-based reasoning hybrid genetic algorithm based on local search method

    Get PDF
    Estimates of project costs in the early stages of a construction project have a significant impact on the operator\u27s decision-making in essential matters, such as the site\u27s decision or the construction period. However, it is not easy to carry out the initial stage with confidence, because information such as design books and specifications is not available. In previous studies, case-based reasoning (CBR) is used to estimate initial construction costs, and genetic algorithms are used to calculate the weight of the retrieve phase in CBR\u27s process. However, it is difficult to draw a better solution than the current one, because existing genetic algorithms use random numbers. To overcome these limitations, we reflect correlation numbers in the genetic algorithms by using the method of local search. Then, we determine the weights using a hybrid genetic algorithm that combines local search and genetic algorithms. A case-based reasoning model was developed using a hybrid genetic algorithm. Then, the model was verified with construction cost data that were not used for the development of the model. As a result, it was found that the hybrid genetic algorithm and case-based reasoning applied with the local search performed better than the existing solution. The detail mean error value was found to be 3.52%, 6.15%, and 0.33% higher for each case than the previous one

    Integrative description of a new Dactylobiotus (Eutardigrada: Parachela) from Antarctica that reveals an intraspecific variation in tardigrade egg morphology

    Get PDF
    Tardigrades constitute one of the most important group in the challenging Antarctic terrestrial ecosystem. Living in various habitats, tardigrades play major roles as consumers and decomposers in the trophic networks of Antarctic terrestrial and freshwater environments; yet we still know little about their biodiversity. The Eutardigrada is a species rich class, for which the eggshell morphology is one of the key morphological characters. Tardigrade egg morphology shows a diverse appearance, and it is known that, despite rare, intraspecific variation is caused by seasonality, epigenetics, and external environmental conditions. Here we report Dactylobiotus ovimutans sp. nov. from King George Island, Antarctica. Interestingly, we observed a range of eggshell morphologies from the new species, although the population was cultured under controlled laboratory condition. Thus, seasonality, environmental conditions, and food source are eliminated, leaving an epigenetic factor as a main cause for variability in this case

    <i>Echinoderes rex</i> n. sp. (Kinorhyncha: Cyclorhagida), the largest <i>Echinoderes</i> species found so far

    Get PDF
    A new kinorhynch species, Echinoderes rex n. sp., is described from the Korea Strait. The new species is characterized by a pair of diminutive lateral terminal spines (19-23 μm) and a trunk length of 482-528 μm, making it the largest Echinoderes described so far. Unique for the new species is also the presence of a type of putative glandular cell outlets that have not been described previously. This paper presents light and scanning electron micrographs of the new structure. In addition, E. rex n. sp. is characterized by having a single middorsal spine on segment 4, lateroventral tubules on segment 5 and 8 and lateroventral acicular spines on segments 6 and 7. A pair of distinct and conspicuously large sieve plates, only described from two other species of the genus, is present on segment 9 in E. rex n. sp. A comparison is made with other species of Echinoderes and the similarities are discussed

    Simultaneous detection and subtyping of porcine endogenous retroviruses proviral DNA using the dual priming oligonucleotide system

    Get PDF
    The purpose of this study was to develop a multiplex PCR that can detect porcine endogenous retrovirus (PERV) proviral genes (pol, envA, envB, envC) and porcine mitochondrial DNA, using a dual priming oligonucleotide (DPO) system. The primer specifically detected the PERV proviral genes pol, envA, envB, envC, and porcine mitochondrial DNA only in samples of pig origin. The sensitivity of the primer was demonstrated by simultaneous amplification of all 5 target genes in as little as 10 pg of pig DNA containing PERV proviral genes and mitochondrial DNA. The multiplex PCR, when applied to field samples, simultaneously and successfully amplified PERV proviral genes from liver, blood and hair root samples. Thus, the multiplex PCR developed in the current study using DPO-based primers is a rapid, sensitive and specific assay for the detection and subtyping of PERV proviral genes

    Identification of single-nucleotide polymorphisms of the prion protein gene in sika deer (Cervus nippon laiouanus)

    Get PDF
    Polymorphisms of the prion protein gene (PRNP) have been detected in several cervid species. In order to confirm the genetic variations, this study examined the DNA sequences of the PRNP obtained from 33 captive sika deer (Cervus nippon laiouanus) in Korea. A total of three single-nucleotide polymorphisms (SNPs) at codons 100, 136 and 226 in the PRNP of the sika deer were identified. The polymorphic site located at codon 100 has not been reported. The SNPs detected at codons 100 and 226 induced amino acid substitutions. The SNP at codon 136 was a silent mutation that does not induce any amino acid change. The genotype and allele frequencies were determined for each of the SNPs
    • …
    corecore