22,228 research outputs found

    Parity-violating πNN\pi NN coupling constant from the flavor-conserving effective weak chiral Lagrangian

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    We investigate the parity-violating pion-nucleon-nucleon coupling constant hπNN1h^1_{\pi NN}, based on the chiral quark-soliton model. We employ an effective weak Hamiltonian that takes into account the next-to-leading order corrections from QCD to the weak interactions at the quark level. Using the gradient expansion, we derive the leading-order effective weak chiral Lagrangian with the low-energy constants determined. The effective weak chiral Lagrangian is incorporated in the chiral quark-soliton model to calculate the parity-violating πNN\pi NN constant hπNN1h^1_{\pi NN}. We obtain a value of about 10710^{-7} at the leading order. The corrections from the next-to-leading order reduce the leading order result by about 20~\%.Comment: 12 page

    The Effects of Sexism and Self-Concept on Body Satisfaction and Clothing Style Preferences for College Students

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    The purpose of this study is to examine how sexism and self-concept are related to body satisfaction and clothing style preferences. First, this study is designed to investigate the influence of self-concept (i.e., self-efficacy and public self-consciousness) on body image. Second, this study examines how sexism moderates the relationship between self-concept and body satisfaction. Third, this study investigates the effect of body satisfaction on clothing style preferences (i.e., fashionability, self-expression, self-confidence)

    Competitive Evolutionary Dynamics of Cloud Service Offerings in Korea: A Path-Dependency Perspective

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    Cloud service for personal users has become more popular world-wide since Apple Inc. launched iCloud storage service in October, 2011. However, such cloud storage service was not new because many global telecom companies, usually called telcos, as well as many portals had already offered similar Internet-based online storage services at that time. As of now, there can be seen hundreds of diverse cloud storage and computing services for both personal and enterprise users in the global market. During last several years, Korean cloud service market has been led by three major telcos, who have launched more advanced and more diversified services competing with each other. Some questions may arise: What makes that happen and what kind of market dynamics affects on the evolution of cloud service offerings? This paper tries to answer these questions by categorizing and analysing 84 cloud services offered by three major telcos in Korea during last three years. As a research framework, Pessemier’s new product classification scheme was employed and precedence relationships among differently positioned service categories were analyzed to figure out the competitive evolutionary dynamics of the market. From the empirical study, path dependency was observed and resource-based view of the market competition was validated. Also, it was found that a player’s next move in service offering to a better position in Pessemier’s product space is quite closely related with the competitive position as well as the company-owned competitive resources like technology competency and company-wide service scope

    Molecular Taxonomy of a Phantom Midge Species (Chaoborus flavicans) in Korea

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    The larvae of Chaoborus are widely distributed in lakes, ponds, and reservoirs. These omnivorous Chaoborus larvae are crucial predators and play a role in structuring zooplankton communities, especially for small-sized prey. Larvae of Chaoborus are commonly known to produce predator-induced polyphenism in Daphnia sp. Nevertheless, their taxonomy and molecular phylogeny are very poorly understood. As a fundamental study for understanding the role of Chaoborus in predator-prey interactions in a freshwater ecosystem, the molecular identification and phylogenetic relationship of Chaoborus were analyzed in this study. A molecular comparison based on partial mitochondrial cytochrome oxidase I (COI) between species in Chaoborus was carried out for the identification of Chaoborus larvae collected from 2 localities in Korea. According to the results, the Chaoborus species examined here was identified as C. flavicans, which is a lake-dwelling species. Furthermore, partial mitochondrial genome including COI, COII, ATP6, ATP8, COIII, and ND3 were also newly sequenced from the species and concatenated 5 gene sequences excluding ATP8 with another 9 dipteran species were compared to examine phylogenetic relationships of C. flavicans. The results suggested that Chaoborus was more related to the Ceratopogonidae than to the Culicidae. Further analysis based on complete mitochondrial DNA sequences and nuclear gene sequences will provide a more robust validation of the phylogenetic relationships of Chaoborus within dipteran lineages

    Sub-100-as timing jitter optical pulse trains from mode-locked Er-fiber lasers

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    We demonstrate sub-100-attosecond timing jitter optical pulse trains generated from free-running, 77.6-MHz repetition-rate, mode-locked Er-fiber lasers. At -0.002(\pm0.001) ps2 net cavity dispersion, the rms timing jitter is 70 as (224 as) integrated from 10 kHz (1 kHz) to 38.8 MHz offset frequency, when measured by a 24-as-resolution balanced optical cross-correlator. To our knowledge, this result corresponds to the lowest rms timing jitter measured from any mode-locked fiber lasers so far. The measured result also agrees fairly well with the Namiki-Haus analytic model of quantum-limited timing jitter in stretched-pulse fiber lasers.Comment: 4 pages, 2 figures, to appear in Optics Letter

    Numerical Sensitivity Tests of Volatile Organic Compounds Emission to PM2.5 Formation during Heat Wave Period in 2018 in Two Southeast Korean Cities

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    A record-breaking severe heat wave was recorded in southeast Korea from 11 July to 15 August 2018, and the numerical sensitivity simulations of volatile organic compound (VOC) to secondarily generated particulate matter with diameter of less than 2.5 mu m (PM2.5) concentrations were studied in the Busan and Ulsan metropolitan areas in southeast Korea. A weather research and forecasting (WRF) model coupled with chemistry (WRF-Chem) was employed, and we carried out VOC emission sensitivity simulations to investigate variations in PM2.5 concentrations during the heat wave period that occurred from 11 July to 15 August 2018. In our study, when anthropogenic VOC emissions from the Comprehensive Regional Emissions Inventory for Atmospheric Transport Experiment-2015 (CREATE-2015) inventory were increased by approximately a factor of five in southeast Korea, a better agreement with observations of PM2.5 mass concentrations was simulated, implying an underestimation of anthropogenic VOC emissions over southeast Korea. The simulated secondary organic aerosol (SOA) fraction, in particular, showed greater dominance during high temperature periods such as 19-21 July, 2018, with the SOA fractions of 42.3% (in Busan) and 34.3% (in Ulsan) among a sub-total of seven inorganic and organic components. This is considerably higher than observed annual mean organic carbon (OC) fraction (28.4 +/- 4%) among seven components, indicating the enhancement of secondary organic aerosols induced by photochemical reactions during the heat wave period in both metropolitan areas. The PM2.5 to PM10 ratios were 0.69 and 0.74, on average, during the study period in the two cities. These were also significantly higher than the typical range in those cities, which was 0.5-0.6 in 2018. Our simulations implied that extremely high temperatures with no precipitation are significantly important to the secondary generation of PM2.5 with higher secondary organic aerosol fraction via photochemical reactions in southeastern Korean cities. Other possible relationships between anthropogenic VOC emissions and temperature during the heat wave episode are also discussed in this study

    Quetiapine Misuse and Abuse: Is It an Atypical Paradigm of Drug Seeking Behavior?

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    Recent case reports in medical literatures suggest that more and more second-generation atypical antipsychotics (AAs) have been prescribed for off-label use; quetiapine (Brand name: Seroquel®) showed increase in its trend for off-label use. Little is known about the reasons behind this trend, although historical sedative and hypnotic prescription patterns suggest that despite relatively superior safety profiles of quetiapine (especially for movement disorders), it may be used for treating substance abuse disorder. In addition, recent studies have shown a strong potential for misuse and abuse (MUA) of quetiapine beyond Food and Drug Administration-approved indications. This includes drug-seeking behaviors, such as feigning symptoms, motivated by quetiapine and use of quetiapine in conjunction with alcohol. Quetiapine appears to be the most documented AA with street values bartered illicitly on the street. A recent report from the Drug Abuse Warning Network has shown a high prevalence of quetiapine-related emergency department visits involving MUA. Several other case studies have found that quetiapine causes seeking behaviors observed in substance use disorder. In fact, the majority of quetiapine MUA involved patients diagnosed with substance use disorder. In the absence of a definitive mechanism of action of quetiapine\u27s reinforcing properties, it is imperative to gather robust evidence to support or refute increasing off-label use of AAs
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