904 research outputs found

    Possible link between Arctic Sea ice and January PM10 concentrations in South Korea

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    In this study, we investigated the possible teleconnection between PM10 concentrations in South Korea and Arctic Sea ice concentrations at inter-annual time scales using observed PM10 data from South Korea, NCEP R2 data, and NOAA Sea Ice Concentration (SIC) data from 2001 to 2018. From the empirical orthogonal function (EOF) analysis, we found that the first mode (TC1) was a large-scale mode for PM10 in South Korea and explained about 27.4% of the total variability. Interestingly, the TC1 is more dominantly influenced by the horizontal ventilation effect than the vertical atmospheric stability effect. The pollution potential index (PPI), which is defined by the weighted average of the two ventilation effects, is highly correlated with the TC1 of PM10 at a correlation coefficient of 0.75, indicating that the PPI is a good measure for PM10 in South Korea at inter-annual time scales. Regression maps show that the decrease of SIC over the Barents Sea is significantly correlated with weakening of high pressure over the Ural mountain range region, the anomalous high pressure at 500 hPa over the Korean peninsula, and the weakening of the Siberian High and Aleutian low. Moreover, these patterns are similar to the correlation pattern with the PPI, suggesting that the variability of SIC over the Barents Sea may play an important role in modulating the variability of PM10 in South Korea through teleconnection from the Barents Sea to the Korean peninsula via Eurasia

    Rationale of decreasing low-density lipoprotein cholesterol below 70 mg/dL in patients with coronary artery disease: A retrospective virtual histology-intravascular ultrasound study

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    Background: The associations between statin and coronary plaque compositional changes were re­ported according to the use of high dose or not. An evaluation of the impact of low-density lipoprotein cholesterol (LDL-C) < 70 mg/dL by using real world dosages of statin on coronary plaque composition was undertaken. Methods: The study subjects consisted of 61 patients (mean 59.9 years old, 45 males) who underwent percutaneous coronary intervention, baseline and follow-up (F/U; mean 8.4 months) virtual histology- -intravascular ultrasound (VH-IVUS) examination. Change of plaque composition at peri-stent area, which was selected in order to measure the identical site at F/U study, was compared according to the F/U LDL-C level. Results: Body mass index, prevalence of dyslipidemia, baseline total cholesterol and baseline LDL-C were significantly lower in F/U LDL-C < 70 mg/dL group (14 segments in 10 patients) than F/U LDL-C ≄ 70 mg/dL group (79 segments in 51 patients). F/U high-density lipoprotein cholesterol (HDL-C, OR 1.06, 95% CI 1.00–1.11, p = 0.054) and F/U LDL-C < 70 mg/dL (OR 3.43, 95% CI 0.97–12.17, p = 0.056) showed strong tendency of regression of necrotic core volume (NCV) ≄ 10%. In multivariable logis­tic regression analysis, F/U HDL-C (OR 1.07, 95% CI 1.01–1.14, p = 0.020) and F/U LDL-C < 70 mg/dL (OR 8.02, 95% CI 1.58–40.68, p = 0.012) were the independent factors for regression of NCV ≄ 10%. Conclusions: Follow-up LDL-C level < 70 mg/dL with any types of statins and increase of HDL-C were associated with regression of NCV ≄ 10% in patients with coronary artery disease

    Topological beaming of light

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    Nanophotonic light emitters are key components in numerous application areas because of their compactness and versatility. Here, we propose a topological beam emitter structure that takes advantage of submicrometer footprint size, small divergence angle, high efficiency, and adaptable beam shaping capability. The proposed structure consists of a topological junction of two guided-mode resonance gratings inducing a leaky Jackiw-Rebbi state resonance. The leaky Jackiw-Rebbi state leads to in-plane optical confinement with funnel-like energy flow and enhanced emission probability, resulting in highly efficient optical beam emission. In addition, the structure allows adaptable beam shaping for any desired positive definite profiles by means of Dirac mass distribution control, which can be directly encoded in lattice geometry parameters. Therefore, the proposed approach provides highly desirable properties for efficient micro–light emitters and detectors in various applications including display, solid-state light detection and ranging, laser machining, label-free sensors, optical interconnects, and telecommunications

    The Effects of Aerobic Exercise Training on Blood Lipid Profiles, Fibrinolytic Activities, and Nitric Oxide Levels in High-fat-diet induced Rats

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    Although exercise training has been utilized to improve vascular function in animals and humans, the impact of moderate intensity exercise training on fibrinolytic activities and nitric oxide (NO) bioavailability has not been well documented. Therefore, the purpose of the current study was to examine the impact of moderate intensity aerobic exercise training on fat mass, blood lipid profiles, fibrinolytic activity, and NO levels in high-fat-diet induced rats. The body weight, fat mass, blood lipid profiles, fibrinolytic activity, and nitrite/nitrate were measured pre- and postexercise (10 weeks) training. The body weight and fat mass reduced significantly in the exercise (EX) group compared to the control (CON) group. Blood lipid profiles and low-density lipoprotein were unchanged in the EX group compared to the CON group. However, triglyceride and free fatty acid were significantly lower in the EX group compared to the CON group, and high-density lipoprotein was significantly greater in the EX group compared to the CON group. In addition, fibrinolytic activity and nitrite/nitrate were significantly greater in the EX compared to the CON group. These results suggest that 10 weeks of the moderated intensity aerobic exercise training improves blood lipid profiles, fibrinolytic activity, and the nitrite/nitrate ratio, which may improve vascular health and reduce obesity-related cardiovascular disease risks in high-fat- diet induced rats

    Neovesical-Urethral Anastomotic Stricture Successfully Treated by Ureteral Dilation Balloon Catheter

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    Neovesical-urethral anastomotic stricture is a complication of orthotopic neobladder, with a reported incidence of 2.7% to 8.8%. Strictures of the neovesico-urethral anastomotic site can be treated with regular self-dilation, but high-grade strictures require a surgical procedure involving incision by electrocautery or cold knife. Here we describe a grade III neovesical-urethral anastomotic stricture after an orthotopic bladder substitution that was successfully treated by use of a ureteral dilation balloon catheter

    New Preamble Design for Reduced-Complexity Timing Acquisition in UWB Systems

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    Abstract-Low-complexity rapid timing acquisition is one of the most pivotal challenges in ultra-wideband (UWB) wireless technology whose short duration pulse results in high resolution in time. In this paper, we propose a new preamble which can reduce the performance degradation caused by diminishing the operational complexity of the coarse timing acquisition. In the reduced-complexity acquisition algorithm, the received preamble is shortened by summing its elements group-by-group and correlated with the known PN sequence having reduced length to find the maximum output value of the correlators. This acquisition algorithm introduces performance deterioration since it loses the impulsive autocorrelation property of the PN sequence after summation. Therefore, we judiciously design a new preamble sequence whose slide correlator output function shows a distinct peak at zero delay and the symmetry even after summation. Simulation results demonstrate that the reducedcomplexity acquisition algorithm exploiting the proposed preamble outperforms the algorithm using the PN sequence as the preamble, while the amount of computational reduction remains the same

    Freshwater and Terrestrial Algae from Ny-Ålesund and Blomstrandhalvþya Island (Svalbard)

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    A field survey of algae and cyanobacteria from terrestrial and freshwater habitats in the vicinity of Ny-Ålesund and on BlomstrandhalvĂžya Island (Svalbard) was performed in June 2009, and results were compared with data from our fieldwork in June 2006. In total, we identified 30 taxa belonging to 23 genera from the specimens collected near Ny-Ålesund (26 taxa) and on BlomstrandhalvĂžya Island (24 taxa). Five species previously unrecorded from this locality are depicted, including astaxanthin-containing Haematococcus sp. collected from BlomstrandhalvĂžya Island. This is the first report on a Haematococcus species from the High Arctic.Une Ă©tude sur le terrain portant sur les algues et les cyanobactĂ©ries d’habitats terrestres et dulçaquicoles dans les environs de Ny-Ålesund et de l’üle BlomstrandhalvĂžya (Svalbard) a Ă©tĂ© rĂ©alisĂ©e en juin 2009, et les rĂ©sultats ont Ă©tĂ© comparĂ©s aux donnĂ©es de notre travail sur le terrain effectuĂ© en juin 2006. En tout, nous avons identifiĂ© 30 taxons appartenant Ă  23 genres Ă  partir de spĂ©cimens prĂ©levĂ©s prĂšs de Ny-Ålesund (26 taxons) et de BlomstrandhalvĂžya (24 taxons). Cinq espĂšces qui n’avaient jamais Ă©tĂ© rĂ©pertoriĂ©es dans cette localitĂ© sont illustrĂ©es, dont l’Haematococcus sp. contenant de l’astaxanthine recueillie Ă  l’üle BlomstrandhalvĂžya. Il s’agit de la premiĂšre fois que l’espĂšce Haematococcus a Ă©tĂ© signalĂ©e dans l’ExtrĂȘme-Arctique
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