457 research outputs found
Lidar measurement of stratospheric aerosol at Syowa Station, Antarctica
Lidar measurement on Antarctic aerosols were made during the Antarctic Middle Atmosphere (AMA) period, 1983 to 1985, at Syowa Station. Topics measured are winter enhancement aerosol layer and volcanic effect of El Chichon on the Antarctic stratosphere aerosols. The large depolarization ratio (maximum value was about 0.8) seems to support sublimation growth of ice crystals. The lidar measurements showed a meaningful time lag between aerosol content increase and depolarization ratio increase. Considering the balloon observations made in early winter, it was speculated that an increase in large particle number concentration also contributed to the winter enhancement. The El Chichon cloud spread to the Antarctic region by the beginning of 1983. The temporal change of integrated backscatter coefficient shows a clear decay pattern, although strong winter enhancement superposes
Lidar observation of the mesospheric sodium layer in Antarctica
The mesospheric sodium layer has been observed at Syowa Station in Antarctica during the wintering period of the 26th Japanese Antarctic Research Expedition. A lidar observation of the polar middle atmosphere at the station has been performed as a part of the Middle Atmosphere Program since 1983. At first stratospheric aerosols have been observed by the system based on a ruby laser. In 1985 a new transmitting system consisting of a tunable dye laser was added to that system to observe the sodium layer, too. The characteristics of the lidar system are given. The results of the mesospheric sodium layer observed on 42 nights during the period from March to October, 1985 are also given
FrameDP: sensitive peptide detection on noisy matured sequences
Summary: Transcriptome sequencing represents a fundamental source of information for genome-wide studies and transcriptome analysis and will become increasingly important for expression analysis as new sequencing technologies takes over array technology. The identification of the protein-coding region in transcript sequences is a prerequisite for systematic amino acid-level analysis and more specifically for domain identification. In this article, we present FrameDP, a self-training integrative pipeline for predicting CDS in transcripts which can adapt itself to different levels of sequence qualities
Long Base-line Measurements of Short Period Mesospheric Gravity Waves During the SEEK Campaign
Simultaneous observations of short‐period (\u3c1 hour) mesospheric gravity waves were made over an extended base‐line (∼660 km) from two sites in Japan (at Shigaraki and Yamagawa) during the SEEK (Sporadic‐E Experiment over Kyushu) campaign, 9–23 August, 1996. Coincident image data obtained on four nights provided a rare opportunity to investigate the horizontal spatial extent and propagation characteristics of the waves in detail. Surprisingly, out of a total of 12 events observed from Shigaraki and 10 from Yamagawa at most only three exhibited similar propagation characteristics at each site. The majority of the wave displays (∼70–75%) had quite dissimilar characteristics suggesting a preponderance for localized wave motions of limited lifetimes and geographical extent. A marked preference for wave progression towards the N‐NE indicates that the gravity waves imaged in the near infrared OH and OI (557.7 nm) nightglow emissions were probably not directly associated with the observed E‐region irregularities
Hyperfine Anomaly of Be Isotopes and Anomalous Large Anomaly in Be
A new result of investigations of the hyperfine structure (hfs) anomaly in Be
isotopes is presented. The hfs constant for Be is obtained by using the
core plus neutron type wave function: . A large hfs anomaly of Be is found, which is mainly due
to a large radius of the halo single particle state.Comment: 14 pages, Late
Multiple Polar Cap Arcs: Akebono (Exos D) Observations
Akebono (Exos D) observations demonstrate that polar cap arcs sometimes have a fine structure, that is, multiple (double or triple) arcs with spacing of a few tens of kilometers. The multiple polar cap arcs are dominantly observed in the nightside polar cap region, suggesting that low background conductance favors the appearance of the structured arcs. A relationship between the spacing and the average energy of the precipitating electrons is investigated. Results show that a higher energy leads to a wider spacing. Akebono observations also show the existence of a downward current region embedded between upward current regions (arcs). Comparison of the observations with results from a coupled magnetosphere-ionosphere Sun-aligned arc model is made, which shows good qualitative agreement between the modeling and observational results on the spacing-energy dependence and the effect of background ionospheric conductance
Particles in classically forbidden area, neutron skin and halo, and pure neutron matter in Ca isotopes
The nucleon density distributions and the thickness of pure neutron matter in
Ca isotopes were systematically studied using the Skyrme-Hartree-Fock model
(SHF) from the -stability line to the neutron drip-line. The pure
neutron matter, related with the neutron skin or halo, was shown to depend not
only on the Fermi levels of the neutrons but also on the orbital angular
momentum of the valence neutrons. New definitions for the thickness of pure
neutron matter are proposed.Comment: 6 pages, 5 figure
Investigation of initiation of gigantic jets connecting thunderclouds to the ionosphere
The initiation of giant electrical discharges called as "gigantic jets"
connecting thunderclouds to the ionosphere is investigated by numerical
simulation method in this paper. Using similarity relations, the triggering
conditions of streamer formation in laboratory situations are extended to form
a criterion of initiation of gigantic jets. The energy source causing a
gigantic jet is considered due to the quasi-electrostatic field generated by
thunderclouds. The electron dynamics from ionization threshold to streamer
initiation are simulated by the Monte Carlo technique. It is found that
gigantic jets are initiated at a height of ~18-24 km. This is in agreement with
the observations. The method presented in this paper could be also applied to
the analysis of the initiation of other discharges such as blue jets and red
sprites.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France
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