1,004 research outputs found
Universal factorization property of certain polycyclic groups
AbstractLet H be a torsion-free strongly polycyclic (torsion-free virtually polycyclic, resp.) group. Let G be any group with maximal condition. We show that there exists a torsion-free strongly polycyclic (torsion-free virtually polycyclic, resp.) group GË and an epimorphism Δ:GâGË such that for any homomorphism Ï:GâH, it factors through GË, i.e., there exists a homomorphism ÏË:GËâH such that Ï=ÏËâΔ. We show that this factorization property cannot be extended to any finitely generated group G. As an application of factorization, we give necessary and sufficient conditions for N(f,g)=R(f,g) to hold for maps f,g:XâY between closed orientable n-manifolds where Ï1(X) has the maximal condition, Y is an infra-solvmanifold, N(f,g) and R(f,g) denote the Nielsen and Reidemeister coincidence numbers, respectively
Strategies For Manufacturing Servitization Of Korean SMEs: By Using Data Envelopment Analysis
This study examines the efficiency of Korean manufacturing SMEs through data envelopment analysis. We divide business processes into support activities (e.g., business management and product planning) and primary activities (e.g., production and sales and after-sales services) to measure the efficiency of each process by product module. Moreover, we verify the effect of manufacturing servitization by comparing between the efficiency of servitized and non-servitized firms. The result shows that support activities are generally more efficient than primary activities and that standardized mass production with option (module 2) and totally customized production (module 4) is more efficient than either standardized mass production without option (module 1) or customized assembly after standardized production (module 3). The results suggest that, as SMEs are small, they have an advantage in support activities but also lack production and sales channel infrastructure. Moreover, modules 2 and 4 are relatively efficient because they can increase their product values via product differentiation. In addition, servitized firms are more efficient than non-servitized firms in almost every process and module, implying that servitization in manufacturing is an effective way to improve product value. Finally, module 1 and the production process are relatively inefficient, while servitized firms have higher efficiency scores than do non servitized firms. Likewise, module 3 and sales and after-sales services are relatively inefficient, while servitized firms have higher efficiency scores than do non servitized firms. There results imply that servitization can be used by Korean manufacturing SMEs to develop efficiently and effectively
Bone-Loading Physical Activity and Alcohol Intake but not BMI Affect Areal Bone Mineral Density in Young College-Aged Korean Women: A Cross-Sectional Study.
The purpose of this cross-sectional study was to determine the differences in areal bone mineral density (aBMD) based on alcohol consumption behaviors, bone-loading history as assessed by a bone-specific physical activity questionnaire (BPAQ), and the body mass index (BMI). College-aged female students (N = 112) were recruited from the universities in Seoul and Gyeonggi province, South Korea. The aBMD of the lumbar spine and non-dominant side of the proximal femur (total hip, TH; femoral neck, FN; femoral trochanter, FT) were measured using dual energy X-ray absorptiometry (DXA). Alcohol consumption was determined by the frequency and amount of alcohol intake during the past 12 months using a self-reported questionnaire. The X-scan plus II was used to measure height (cm), body mass (kg), fat-free mass (FFM, kg), and % body fat. Drinking two or more times alcohol per week was associated with greater aBMD of the TH (p = 0.04â0.002) and FN (p = 0.043) compared to a lower frequency of alcohol consumption and 2â4 times per month, respectively. Based on the drinking amount per occasion, there were no significant group differences (p \u3e 0.05) in aBMD at any of the sites. The highest group of total BPAQ had greater aBMD of the TH, FN, and FT versus the lowest (p = 0.023â0.009) and mid of total BPAQ groups (p = 0.004â0.009). Additionally, the highest group had greater aBMD of the lumbar spine compared to the mid group (p = 0.001). No significant group differences in aBMD at any of the sites were noted based on the BMI (p \u3e 0.05). Young college-aged women with greater bone-loading physical activity showed greater aBMD at the TH, FN, FT, and lumbar spine, while a moderate alcohol intake was associated with greater aBMD of the TH and FN. These findings have clinical implications for young women who may not participate in high-impact physical activity and are binge drinkers
Structure and spectral features of H+(H2O)(7): Eigen versus Zundel forms
The two dimensional (2D) to three dimensional (3D) transition for the protonated water cluster has been controversial, in particular, for H+(H2O)(7). For H+(H2O)(7) the 3D structure is predicted to be lower in energy than the 2D structure at most levels of theory without zero-point energy (ZPE) correction. On the other hand, with ZPE correction it is predicted to be either 2D or 3D depending on the calculational levels. Although the ZPE correction favors the 3D structure at the level of coupled cluster theory with singles, doubles, and perturbative triples excitations [CCSD(T)] using the aug-cc-pVDZ basis set, the result based on the anharmonic zero-point vibrational energy correction favors the 2D structure. Therefore, the authors investigated the energies based on the complete basis set limit scheme (which we devised in an unbiased way) at the resolution of the identity approximation Moller-Plesset second order perturbation theory and CCSD(T) levels, and found that the 2D structure has the lowest energy for H+(H2O)(7) [though nearly isoenergetic to the 3D structure for D+(D2O)(7)]. This structure has the Zundel-type configuration, but it shows the quantum probabilistic distribution including some of the Eigen-type configuration. The vibrational spectra of MP2/aug-cc-pVDZ calculations and Car-Parrinello molecular dynamics simulations, taking into account the thermal and dynamic effects, show that the 2D Zundel-type form is in good agreement with experiments. (c) 2006 American Institute of Physics.open353
The Impact of Overactive Bladder on Health-Related Quality of Life, Sexual Life and Psychological Health in Korea
Purpose We aimed to estimate the prevalence of overactive bladder (OAB) in Korea, to assess the variation in prevalence by sex and age, and to measure the impact of OAB on quality of life. Methods A population-based, cross-sectional telephone survey was conducted between April and June 2010 with a questionnaire regarding the prevalence of OAB, demographics, and the impact of OAB on quality of life. A geographically stratified random sample of men and women aged â„30 years was selected. Results The overall prevalence of OAB was 22.9% (male, 19%; female, 26.8%). Of a total of 458 participants with OAB, 37.6% and 19.9% reported moderate or severe impact on their daily life and sexual life (5.6% and 3.5%, respectively, in participants without OAB). Anxiety and depression were reported by 22.7% and 39.3% of participants with OAB, respectively (9.7% and 22.8%, respectively, in participants without OAB). Only 19.7% of participants with OAB had consulted a doctor for their voiding symptoms, but 50.7% of respondents with OAB were willing to visit a hospital for the management of their OAB symptoms. Conclusions This study confirmed that OAB symptoms are highly prevalent in Korea, and many sufferers appear to have actively sought medical help. OAB has severe effects on daily and sexual life as well as psychological health
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Rational Perturbation of the Fluorescence Quantum Yield in EmissionâTunable and Predictable Fluorophores (SeoulâFluors) by a Facile Synthetic Method Involving CâH Activationâ
Abstract Fluorescence imaging enables the uniquely sensitive observation of functionalâ and molecularârecognition events in living cells. However, only a limited range of biological processes have been subjected to imaging because of the lack of a design strategy and difficulties in the synthesis of biosensors. Herein, we report a facile synthesis of emissionâtunable and predictable SeoulâFluors, 9âarylâ1,2âdihydrolopyrrolo[3,4âb]indolizinâ3âones, with various R1 and R2 substituents by coinageâmetalâcatalyzed intramolecular 1,3âdipolar cycloaddition and subsequent palladiumâmediated CâH activation. We also showed that the quantum yields of SeoulâFluors are controlled by the electronic nature of the substituents, which influences the extent of photoinduced electron transfer. On the basis of this understanding, we demonstrated our design strategy by the development of a SeoulâFluorâbased chemosensor 20 for reactive oxygen species that was not accessible by a previous synthetic route
A Study on Performance Design Using a Sprinkler System for Fire-Spread Prevention of a Building Exterior
A glass exterior material is normally used in buildings, but it also comes with a disadvantageâit is easily damaged by fire. If the glass exterior material is damaged, a fire can rapidly propagate inside the building space, leading to a lot of damage from the flame transfer to the other space. In this study, the performance of a sprinkler for flame propagation prevention was evaluated during an experiment with an actual proof fire. The study found that where the sprinkler is installed with the glass exterior material, the temperature does not exceed 60°C until the end of the test due to the effect of the water curtain. In the glass exterior material where the sprinkler is not installed, the temperature rapidly increased just after starting the experiment, and caused damage 21 minutes and 30 seconds after starting the test
The Study on Fire Safety by a Real-Scale Combustion Experiment of Composite Material
In this study, a real-scale combustion experiment was carried out for a Styrofoam and glass wool sandwich panel to figure out the fire safety for the composite material used for a building. In the experiment, a heat release rate of a sandwich panel was measured by the ISO 9705 fire test method. Research has also tested and compared temperature change in the Large Scale Calorimeter (LSC) experiment equipment to evaluate the structural safety of the structure body. As a result of the experiment, the structural body with the Styrofoam sandwich panel collapsed which was caused by propagation, and in case of the glass wool sandwich panel, the combustion did no propagate inside. Since the composite material experiences various types of fire hazards depending on the combustion characteristics of the core material, the exact combustion characteristic should be expected by the full-scale combustion experiment
Genome-scale metabolic model of the fission yeast Schizosaccharomyces pombe and the reconciliation of in silico/in vivo mutant growth
<p>Abstract</p> <p>Background</p> <p>Over the last decade, the genome-scale metabolic models have been playing increasingly important roles in elucidating metabolic characteristics of biological systems for a wide range of applications including, but not limited to, system-wide identification of drug targets and production of high value biochemical compounds. However, these genome-scale metabolic models must be able to first predict known <it>in vivo</it> phenotypes before it is applied towards these applications with high confidence. One benchmark for measuring the <it>in silico</it> capability in predicting <it>in vivo</it> phenotypes is the use of single-gene mutant libraries to measure the accuracy of knockout simulations in predicting mutant growth phenotypes.</p> <p>Results</p> <p>Here we employed a systematic and iterative process, designated as Reconciling <it>In silico/in vivo</it> mutaNt Growth (RING), to settle discrepancies between <it>in silico</it> prediction and <it>in vivo</it> observations to a newly reconstructed genome-scale metabolic model of the fission yeast, <it>Schizosaccharomyces pombe</it>, SpoMBEL1693. The predictive capabilities of the genome-scale metabolic model in predicting single-gene mutant growth phenotypes were measured against the single-gene mutant library of <it>S. pombe</it>. The use of RING resulted in improving the overall predictive capability of SpoMBEL1693 by 21.5%, from 61.2% to 82.7% (92.5% of the negative predictions matched the observed growth phenotype and 79.7% the positive predictions matched the observed growth phenotype).</p> <p>Conclusion</p> <p>This study presents validation and refinement of a newly reconstructed metabolic model of the yeast <it>S. pombe</it>, through improving the metabolic modelâs predictive capabilities by reconciling the <it>in silico</it> predicted growth phenotypes of single-gene knockout mutants, with experimental <it>in vivo</it> growth data.</p
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