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  • 1
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    Observation system simulation experiment for new radio occultation observations using multiple small satellites on Venus (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-04-25
    Description: The radio occultation (RO) observations using multiple small satellites are expected not to be interrupted by a thick global cloud layer at about 48–70 km altitudes, and to enable frequent observations of the global vertical temperature distribution at 40–90 km altitudes. In this study, we focus on a phenomenon peculiar to Venus called “cold collar”, in which the polar region becomes warmer than the surrounding latitudes of 60–80 ° at 65 km altitude, and the Observation System Simulation Experiment (OSSE) is carried out assuming RO observation by satellites to be launched in the future. For the Venus assimilation system, “ALEDAS-V” (AFES LETKF Data Assimilation System for Venus) based on LETKF (Local Ensemble Transform Kalman Filter) is used. For the ensemble forecast, the Venus general circulation model “AFES-Venus” is used. For the pseudo-observation data, we use the temperature output of the IPSL Venus GCM (now called the Venus “Planetary Climate Model; PCM”) which represent ideal cold collar by radiative forcing. The temperature at 40–90 km altitudes corresponding to observation points obtained by orbit calculations is used as pseudo-observation data. As a result, while the experiment without assimilation (free run) cannot reproduce the cold collar at 67 km altitude, the RO OSSE reproduces it.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 2
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    Super-rotation independent of horizontal diffusion reproduced in a Venus GCM (AFES-Venus) (2023)
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Details
    Publication Date: 2023-04-25
    Description: In the Venus atmosphere, fast zonal wind has been observed, which is called super-rotation, because it is much faster than the rotation period of the solid part of the planet. So far, Venus general circulation models (VGCMs) have been used to study the super-rotation and several studies obtained fully developed super-rotation faster than 100 m/s. It has been suggested that horizontal diffusion and resolution are important factors to generate and maintain the super-rotation in the general circulation model because waves which transport angular momentum are sensitive to them. Here, we investigated how the super-rotation depends on the magnitude of horizontal hyper diffusion using a VGCM (AFES-Venus) with medium and high resolutions (T42L60 and T159L120 where T and L denote the triangular truncation number for spherical harmonics and vertical levels, respectively). In both the runs, we found a parameter range where the structure of fully developed super-rotation is almost independent of the magnitude of horizontal diffusion. Spectral analysis shows that unrealistically strong super-rotation is developed when medium-scale disturbances are dissipated by stronger horizontal diffusion. On the other hand, artificially weak super-rotation is also realized because spurious small-scale disturbances are accumulated when the horizontal diffusion is too weak. We elucidated that the super-rotation reproduced in our VGCM is caused by resolved eddies. Moreover, we could estimate appropriate magnitude of horizontal diffusion by the spectral analysis. This study has broad implications for the planetary atmospheric science, not only in modeling but also in observational aspects.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
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  • 3
    Electronic Resource
    Electronic Resource
    Time-gated gain cell for frequency-stable, single-longitudinal-mode operation of a transverse, electric, atmospheric CO2 laser (1993)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 1663-1664 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A time-gated gain cell has been demonstrated as a method for producing single-longitudinal-mode output from a pulsed transverse, electric, atmospheric (TEA) carbon dioxide laser. The gain cell is operated as an oscillator during the time between the laser pulses and is rapidly dropped below threshold during the TEA pulse output to avoid degradation of the gain-switched spike in the laser pulse. Standard dither-stabilization techniques can be used during the time between the laser pulses (cw oscillation) to position the output coupler for single-mode operation and frequency stabilization while the gain cell is operated above threshold.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144046
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  • 4
    Electronic Resource
    Electronic Resource
    Magneto-optic buried channel waveguides for a 45° nonreciprocal waveguide rotator (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 2744-2746 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An optical isolation ratio of −21.1 dB at λ=1.55 μm is obtained for a LPE-grown La and Ga substituted YIG single-mode buried channel waveguide. Waveguides about 3 mm long end-butted to single-mode fibers show an overall insertion loss of less than 2 dB. The Ar ion-beam etching technique using a three layered etching mask provides sufficient control of both the width (∼4 μm) and height (∼4 μm) of the core ridge. The core and cladding layers are individually grown from melts with different compositions in order to reduce stress-induced birefringence. The good reproducibility with which 45° waveguide rotators exhibiting a circular near-field intensity pattern can be fabricated will enable us to realize optical integration in future systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.110321
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  • 5
    Electronic Resource
    Electronic Resource
    A ytterbium- and neodymium-co-doped yttrium aluminum garnet–buried channel waveguide laser pumped at 0.81 μm (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 582-584 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this paper we will explain the preparation of an epitaxially grown ytterbium- and neodymium-co-doped yttrium aluminum garnet [(Yb,Nd):YAG]–buried channel waveguide laser on a YAG substrate. Waveguides, whose cores are formed with Ar ion beam etching, demonstrate single-mode operation. The (Yb,Nd):YAG waveguide laser operates at 1.03 μm when pumped at 0.81 μm, as a result of a nonradiative energy transfer from Nd3+ ions to Yb3+ ions. The incident threshold and slope efficiency of the 5 mm long waveguide laser are 235 mW and 13%, respectively. Output power of 50 mW is obtained for an incident power of 620 mW at room temperature. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115395
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  • 6
    Electronic Resource
    Electronic Resource
    Room-temperature operation of an Yb-doped Gd3Ga5O12 buried channel waveguide laser at 1.025 μm wavelength (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 2177-2179 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An epitaxially grown ytterbium-doped gadolinium gallium garnet (Yb:GGG) buried channel waveguide laser is prepared on an yttrium substituted GGG substrate (Y:GGG). The effective light guiding structure is obtained as a result of the difference of refractive indices of Yb:GGG and Y:GGG. The Yb:GGG waveguide exhibits single-mode 1.025 μm lasing operation at room temperature. The incident threshold and slope efficiency of the 5-mm-long waveguide laser when pumped at 0.941 μm are 80 mW and 13.4%, respectively. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.116004
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  • 7
    Electronic Resource
    Electronic Resource
    RNA Structure Prediction (1988)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Biophysics and Biomolecular Structure 17 (1988), S. 167-192 
    Details
    ISSN: 0084-6589
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.bb.17.060188.001123
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  • 8
    Electronic Resource
    Electronic Resource
    Role of elastase and active oxygen species in gastric mucosal injury induced by aspirin administration in Helicobacter pylori-infected Mongolian gerbils (2002)
    Oxford UK : Blackwell Science Ltd.
    Alimentary pharmacology & therapeutics 16 (2002), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: H. pylori infection potentiates aspirin-induced gastric mucosal injury by mechanisms that include accumulation of activated neutrophils.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To determine the role of elastase and active oxygen species (AOS) produced by activated neutrophils in the gastric mucosal injury induced by administration of acidified aspirin to H. pylori-infected Mongolian gerbils.〈section xml:id="abs1-3"〉〈title type="main"〉Methods: H. pylori ATCC43504 culture broth was administered by oral gavage to male Mongolian gerbils at 7 weeks of age. After 4 weeks, acidified aspirin (400 mg/kg) was administered orally, and 3 h later, the total area of gastric erosions, myeloperoxidase (MPO) activity (an index of neutrophil accumulation), thiobarbituric acid-reactive substances (TBARS, an index of lipid peroxidation), and KC/GRO (a chemo-attractive cytokine in rodents) were measured in gastric mucosa. To determine the role of elastase or AOS derived from neutrophils in these circumstances, ONO-5046 (an elastase inhibitor), a combination of superoxide dismutase (SOD) and catalase (scavengers of AOS), and polaprezinc (an anti-ulcer agent with anti-inflammatory effects) were administered before aspirin.〈section xml:id="abs1-4"〉〈title type="main"〉Results:ONO-5046 inhibited the increase in gastric erosions and mucosal TBARS induced by administration of aspirin to H. pylori-infected gerbils, but not the increases in MPO activity or KC/GRO contents. A combination of SOD and catalase or polaprezinc significantly reduced gastric erosions, TBARS concentrations, MPO activity and KC/GRO concentration.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusions:These results suggest that neutrophil-derived-elastase and -oxidants play an important role in the gastric mucosal injury induced by administration of aspirin to H. pylori-infected gerbils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2036.16.s2.32.x
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  • 9
    Electronic Resource
    Electronic Resource
    Enterotoxin of Clostridiumperfringens type a forms ion-permeable channels in a lipid bilayer membrane
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 156 (1988), S. 551-556 
    Details
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0006-291X(88)80877-5
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  • 10
    Electronic Resource
    Electronic Resource
    Tetanus toxin blocks Ca spikes in neuroblastoma clone N1E-115 cells
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 115 (1983), S. 788-793 
    Details
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/S0006-291X(83)80003-5
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