498 research outputs found

    Extreme waves generated by Typhoon Bolaven (201215) in Southern Korean waters

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    Unusual extreme waves were generated by Typhoon Bolaven (201215) in the Southern Korean Waters\ud (SKW) and gave destructive damages to the breakwaters of Seogwipo Harbor at Jeju Island. The waves were far\ud exceeding the design wave height (Hs50yrs 9.3m) and their duration was 14hours. The duration is a very significant\ud factor as much as the design wave height for breakwater armor stability in terms of cumulative damages. A significant\ud increase in strong typhoon intensity and duration in North West Pacific (NWP) due to global warming has been reported\ud and also in landfall typhoons on Korea/Japan in a recent decade. The frequency of typhoon passed SKW region had an\ud inter-annual and also a decadal variation and decreased in recent years, but several strong typhoons were occurred.\ud Bolaven was affected by high pressure distribution located above the warm eddy region to track toward NNW rather\ud than NE as usual in August. The extreme waves were analyzed with respect to typhoon genesis, evolution of the waves\ud through extensive measured data and model simulation. Numerical models of TC96 for the wind fields and WAM4.5.2\ud for the waves were used after calibration with measured data and correction of Cd in wave growth term. They produced\ud reasonably good results. It was found that the extreme waves were evolved by combination of distant large swell and\ud strong wind seas generated by consistent strong winds from front right quadrant of typhoon track for such a long time.\ud The variation of those waves was relatively small as 1-2m, which might be due to limitation of wave growth for\ud U>30m/s and bottom energy dissipation of long period waves in the region. It is essential to hindcast accurately the\ud extreme waves for design of the breakwaters and also for assessment of coastal flooding and coastal erosion in a\ud warming climate

    Observation of the Smectic C -- Smectic I Critical Point

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    We report the first observation of the smectic C--smectic I (C--I) critical point by Xray diffraction studies on a binary system. This is in confirmity with the theoretical idea of Nelson and Halperin that coupling to the molecular tilt should induce hexatic order even in the C phase and as such both C and I (a tilted hexatic phase) should have the same symmetry. The results provide evidence in support of the recent theory of Defontaines and Prost proposing a new universality class for critical points in layered systems.Comment: 9 pages Latex and 5 postscript figures available from [email protected] on request, Phys.Rev.Lett. (in press

    Simple models of small world networks with directed links

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    We investigate the effect of directed short and long range connections in a simple model of small world network. Our model is such that we can determine many quantities of interest by an exact analytical method. We calculate the function V(T)V(T), defined as the number of sites affected up to time TT when a naive spreading process starts in the network. As opposed to shortcuts, the presence of un-favorable bonds has a negative effect on this quantity. Hence the spreading process may not be able to affect all the network. We define and calculate a quantity named the average size of accessible world in our model. The interplay of shortcuts, and un-favorable bonds on the small world properties is studied.Comment: 15 pages, 9 figures, published versio

    CFD analysis of liquid stream going through the wire-screen mesh

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    Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.Wire-screen mesh is normally used for the removal of particles from a liquid stream. Here we consider a system where fluid passes wire-screen mesh perpendicularly. The configurations of wire-screen mesh such as diameter and shape factor of wire affect the stream of fluid going through the screen. In this study, we performed a theoretical approach to the relation between wire mesh and fluid stream with computational fluid dynamics (CFD). FLUENT is used for the simulation. Head loss can be estimated by Rose equation when the stream passes through the wire-mesh (Rose 1945). The drag coefficient (CD) varies with the stream types. The other parameters depend on a specific mesh, velocity and pressure. In the experiment we used a screen of 50 mesh-size and water as a fluid. The pressure drop during water flow was determined. The average and maximum velocities of water were calculated. On the basis of these values, we derived a proportional factor between the velocity of fluid and head loss that can estimate CD.cs201

    Altered expression of microRNA-451 in eutopic endometrium of baboons ( Papio anubis ) with endometriosis

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    Are microRNAs (miRs) altered in the eutopic endometrium (EuE) of baboons following the induction of endometriosis

    Photoemission and x-ray absorption spectroscopy study of electron-doped colossal magnetoresistance manganite: La0.7Ce0.3MnO3 film

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    The electronic structure of La0.7Ce0.3MnO3 (LCeMO) thin film has been investigated using photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). The Ce 3d core-level PES and XAS spectra of LCeMO are very similar to those of CeO2, indicating that Ce ions are far from being trivalent. A very weak 4f resonance is observed around the Ce 4d \to 4f absorption edge, suggesting that the localized Ce 4f states are almost empty in the ground state. The Mn 2p XAS spectrum reveals the existence of the Mn(2+) multiplet feature, confirming the Mn(2+)-Mn(3+) mixed-valent states of Mn ions in LCeMO. The measured Mn 3d PES/XAS spectra for LCeMO agrees reasonably well with the calculated Mn 3d PDOS using the LSDA+U method. The LSDA+U calculation predicts a half-metallic ground state for LCeMO.Comment: 7 pages, 7 figure

    Golgi Outpost Synthesis Impaired by Toxic Polyglutamine Proteins Contributes to Dendritic Pathology in Neurons

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    Dendrite aberration is a common feature of neurodegenerative diseases caused by protein toxicity, but the underlying mechanisms remain largely elusive. Here, we show that nuclear polyglutamine (polyQ) toxicity resulted in defective terminal dendrite elongation accompanied by a loss of Golgi outposts (GOPs) and a decreased supply of plasma membrane (PM) in Drosophila class IV dendritic arborization (da) (C4 da) neurons. mRNA sequencing revealed that genes downregulated by polyQ proteins included many secretory pathway-related genes, including COPII genes regulating GOP synthesis. Transcription factor enrichment analysis identified CREB3L1/CrebA, which regulates COPII gene expression. CrebA overexpression in C4 da neurons restores the dysregulation of COPII genes, GOP synthesis, and PM supply. Chromatin immunoprecipitation (ChIP)-PCR revealed that CrebA expression is regulated by CREB-binding protein (CBP), which is sequestered by polyQ proteins. Furthermore, co-overexpression of CrebA and Rac1 synergistically restores the polyQ-induced dendrite pathology. Collectively, our results suggest that GOPs impaired by polyQ proteins contribute to dendrite pathology through the CBP-CrebA-COPII pathway. ? 2017 The Author(s)113Ysciescopu

    Doing quantitative research in the learning sciences and CSCL:current developments and applications

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    While quantitative methods are continuously developed in various fields of origin,such as psychology, the specific applications in the core field of learning sciences and CSCL are less well advanced. In this workshop, we explore and discuss current methodological topics in three relevant fields of empirical research: (1) obtaining data, (2) analyzing data, and (3) sharing data, replicating and integrating findings. Outcomes of the discussions are planned to be published in short guidelines facilitating the application of latest developments in quantitative methods in the learning sciences and CSCL research.<br/

    Doing quantitative research in the learning sciences and CSCL:current developments and applications

    Get PDF
    While quantitative methods are continuously developed in various fields of origin,such as psychology, the specific applications in the core field of learning sciences and CSCL are less well advanced. In this workshop, we explore and discuss current methodological topics in three relevant fields of empirical research: (1) obtaining data, (2) analyzing data, and (3) sharing data, replicating and integrating findings. Outcomes of the discussions are planned to be published in short guidelines facilitating the application of latest developments in quantitative methods in the learning sciences and CSCL research.<br/

    Slewing Mirror Telescope and the Data-Acquisition System for the UFFO-Pathfinder

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    The Ultra-Fast Flash Observatory (UFFO) aims to detect the earliest moment of Gamma-Ray Bursts (GRBs) which is not well known, resulting into the enhancement of GRB mechanism understanding. The pathfinder mission was proposed to be a scaled-down version of UFFO, and only contains the UFFO Burst Alert & Trigger Telescope (UBAT) measuring the X-ray/gamma-ray with the wide-field of view and the Slewing Mirror Telescope (SMT) with a rapid-response for the UV/optical photons. Once the UBAT detects a GRB candidate with the position accuracy of 10 arcmin, the SMT steers the UV/optical photons from the candidate to the telescope by the fast rotatable mirror and provides the early UV/optical photons measurements with 4 arcsec accuracy. The SMT has a modified Ritchey-Chrètien telescope with the aperture size of 10 cm diameter including the rotatable mirror and the image readout by the intensified charge-coupled device. There is a key board called the UFFO Data Acquisition system (UDAQ) that manages the communication of each telescope and also of the satellite and the UFFO overall operation. This pathfinder is designed and built within the limited size and weight of  ~20 kg and the low power consumption up to  ~30 W. We will discuss the design and performance of the UFFO-pathfinder, and its integration to the Lomonosov satellite
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