9,231 research outputs found

    Soliton cellular automaton associated with G2(1)G_2^{(1)} crystal base

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    We calculate the combinatorial RR matrix for all elements of BlB1\mathcal{B}_l\otimes \mathcal{B}_1 where Bl\mathcal{B}_l denotes the G2(1)G_2^{(1)}-perfect crystal of level ll, and then study the soliton cellular automaton constructed from it. The solitons of length ll are identified with elements of the A1(1)A_1^{(1)}-crystal B~3l\tilde{\mathcal{B}}_{3l}. The scattering rule for our soliton cellular automaton is identified with the combinatorial RR matrix for A1(1)A_1^{(1)}-crystals

    Nominal Stock Price Anchors: A Global Phenomenon?

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    Weld et al. (2009) find that the average nominal U.S. stock price has been approximately $25 since the Great Depression. They report that this nominal price fixation is primarily a U.S. or North American phenomenon. Using a larger data set from 38 countries, we show that this nominal price fixation is a global phenomenon. We exploit the introduction of the euro in 1999 to show that stock splits maintain these nominal stock price anchors. Generally, firms in countries with larger drops in nominal prices had fewer stock splits after stock prices were displayed in euros

    Retrievals of All-Weather Daily Air Temperature Using MODIS and AMSR-E Data

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    Satellite optical-infrared remote sensing from the Moderate Resolution Imaging Spectroradiometer (MODIS) provides effective air temperature (Ta) retrieval at a spatial resolution of 5 km. However, frequent cloud cover can result in substantial signal loss and remote sensing retrieval error in MODIS Ta. We presented a simple pixel-wise empirical regression method combining synergistic information from MODIS Ta and 37 GHz frequency brightness temperature (Tb) retrievals from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) for estimating surface level Ta under both clear and cloudy sky conditions in the United States for 2006. The instantaneous Ta retrievals showed favorable agreement with in situ air temperature records from 40 AmeriFlux tower sites; mean R2 correspondence was 86.5 and 82.7 percent, while root mean square errors (RMSE) for the Ta retrievals were 4.58 K and 4.99 K for clear and cloudy sky conditions, respectively. Daily mean Ta was estimated using the instantaneous Ta retrievals from day/night overpasses, and showed favorable agreement with local tower measurements (R2 = 0.88; RMSE = 3.48 K). The results of this study indicate that the combination of MODIS and AMSR-E sensor data can produce Ta retrievals with reasonable accuracy and relatively fine spatial resolution (~5 km) for clear and cloudy sky conditions

    Plasmonic colloidal nanoparticles with open eccentric cavities via acid-induced chemical transformation

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    Surface-enhanced Raman spectroscopy (SERS) has been considered a promising technique for the detection of trace molecules in biomedicine and environmental monitoring. The ideal metal nanoparticles for SERS must not only fulfill important requirements such as high near-field enhancement and a tunable far-field response but also overcome the diffusion limitation at extremely lower concentrations of a target material. Here, we introduce a novel method to produce gold nanoparticles with open eccentric cavities by selectively adapting the structure of non-plasmonic nanoparticles via acid-mediated surface replacement. Copper oxide nanoparticles with open eccentric cavities are first prepared using a microwave-irradiation-assisted surfactant-free hydrothermal reaction and are then transformed into gold nanoparticles by an acidic gold precursor while maintaining their original structure. Because of the strong near-field enhancement occurring at the mouth of the open cavities and the very rough surfaces resulting from the uniformly covered hyperbranched sharp multi-tips and the free access of SERS molecules inside of the nanoparticles without diffusion limitation, adenine, one of the four bases in DNA, in an extremely diluted aqueous solution (1.0 pM) was successfully detected with excellent reproducibility upon laser excitation with a 785-nm wavelength. The gold nanoparticles with open eccentric cavities provide a powerful platform for the detection of ultra-trace analytes in an aqueous solution within near-infrared wavelengths, which is essential for highly sensitive, reliable and direct in vivo analysis.None1132sciescopu

    Radio and x-ray shocks in clusters of galaxies

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    Radio relics detected in the outskirts of galaxy clusters are thought to trace radio-emitting relativistic electrons accelerated at cosmological shocks. In this study, using the cosmological hydrodynamic simulation data for the large-scale structure formation and adopting a diffusive shock acceleration (DSA) model for the production of cosmic-ray (CR) electrons, we construct mock radio and X-ray maps of simulated galaxy clusters that are projected in the sky plane. Various properties of shocks and radio relics, including the shock Mach number, radio spectral index, and luminosity, are extracted from the synthetic maps and compared with observations. A substantial fraction of radio and X-ray shocks identified in these maps involve multiple shock surfaces along lines of sight (LOSs), and the morphology of shock distributions in the maps depends on the projection direction. Among multiple shocks in a given LOS, radio observations tend to pick up stronger shocks with flatter radio spectra, while X-ray observations preferentially select weaker shocks with larger kinetic energy flux. As a result, in some cases the shock Mach numbers and locations derived from radio and X-ray observations could differ from each other. We also find that the distributions of the spectral index and radio power of the synthetic radio relics are somewhat inconsistent with those of observed real relics; a bit more radio relics have been observed closer to the cluster core and with steeper spectral indices. We suggest that the inconsistency could be explained if very weak shocks with M-s less than or similar to 2 accelerate CR electrons more efficiently, compared with the DSA model adopted here.open0

    Ex vivo promoter analysis of antiviral heat shock cognate 70B gene in Anopheles gambiae

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    <p>Abstract</p> <p>Background</p> <p>The <it>Anopheles gambiae </it>heat shock cognate gene (<it>hsc70B</it>) encodes a constitutively expressed protein in the <it>hsp70 </it>family and it functions as a molecular chaperone for protein folding. However, the expression of <it>hsc70B </it>can be further induced by certain stimuli such as heat shock and infection. We previously demonstrated that the <it>An. gambiae hsc70B </it>is induced during o'nyong-nyong virus (ONNV) infection and subsequently suppresses ONNV replication in the mosquito. To further characterize the inducibility of <it>hsc70B </it>by ONNV infection in <it>An. gambiae</it>, we cloned a 2.6-kb region immediately 5' upstream of the starting codon of <it>hsc70B </it>into a luciferase reporter vector (pGL3-Basic), and studied its promoter activity in transfected Vero cells during infection with o'nyong-nyong, West Nile and La Crosse viruses.</p> <p>Results</p> <p>Serial deletion analysis of the <it>hsc70B </it>upstream sequence revealed that the putative promoter is likely located in a region 1615–2150 bp upstream of the <it>hsc70B </it>starting codon. Sequence analysis of this region revealed transcriptional regulatory elements for heat shock element-binding protein (HSE-bind), nuclear factor κB (NF-κB), dorsal (Dl) and fushi-tarazu (Ftz). Arbovirus infection, regardless of virus type, significantly increased the <it>hsc70B </it>promoter activity in transfected Vero cells.</p> <p>Conclusion</p> <p>Our results further validate the transcriptional activation of <it>hsc70B </it>during arbovirus infection and support the role of specific putative regulatory elements. Induction by three taxonomically distinct arboviruses suggests that the HSC70B protein may be expressed to cope with cellular stress imposed during infection.</p

    First report of Perkinsus honshuensis in the variegated carpet shell clam Ruditapes variegatus in Korea

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    The recent discovery of Perkinsus honshuensis, a new Perkinsus species infecting Manila clams Ruditapes philippinarum (Sowerby, 1852), in Japan, suggested that, based on proximity, P. honshuensis could also be in Korean waters, where to date, P. olseni was believed to be the only Perkinsus species present. Perkinsus sp. infections consistently occurred among Ruditapes variegatus clams on a pebble beach on Jeju Island, off the south coast of Korea. The typical \u27signet ring\u27 morphology of the parasite was observed in the connective tissue of the digestive gland, and infection intensity was comparatively low (3.3 x 10(3) +/- 1.2 x 10(4) to 1.3 x 10(4) +/- 6.1 x 10(4) cells g(-1) gill weight). Further DNA analyses of internal transcribed spacer (ITS-1, 5.8S and ITS-2) and non-transcribed spacer (NTS) regions of the parasite showed 98.9-99.8 and 98.5-99.5% similarity to those of P. honshuensis from Japan, respectively. Phylogenetic analyses using ITS and NTS sequences indicated that Perkinsus sp. from Jeju formed a highly supported clade with P. honshuensis. This is the first report of P. honshuensis infections in clams in Korean waters and the first report of R. variegatus as a host for that parasite

    Geometric and combinatorial realizations of crystal graphs

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    For irreducible integrable highest weight modules of the finite and affine Lie algebras of type A and D, we define an isomorphism between the geometric realization of the crystal graphs in terms of irreducible components of Nakajima quiver varieties and the combinatorial realizations in terms of Young tableaux and Young walls. For affine type A, we extend the Young wall construction to arbitrary level, describing a combinatorial realization of the crystals in terms of new objects which we call Young pyramids.Comment: 34 pages, 17 figures; v2: minor typos corrected; v3: corrections to section 8; v4: minor typos correcte
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