2,488 research outputs found
Development of 2MASS Catalog Server Kit
We develop a software kit called "2MASS Catalog Server Kit" to easily
construct a high-performance database server for the 2MASS Point Source Catalog
(includes 470,992,970 objects) and several all-sky catalogs. Users can perform
fast radial search and rectangular search using provided stored functions in
SQL similar to SDSS SkyServer. Our software kit utilizes open-source RDBMS, and
therefore any astronomers and developers can install our kit on their personal
computers for research, observation, etc. Out kit is tuned for optimal
coordinate search performance. We implement an effective radial search using an
orthogonal coordinate system, which does not need any techniques that depend on
HTM or HEALpix. Applying the xyz coordinate system to the database index, we
can easily implement a system of fast radial search for relatively small (less
than several million rows) catalogs. To enable high-speed search of huge
catalogs on RDBMS, we apply three additional techniques: table partitioning,
composite expression index, and optimization in stored functions. As a result,
we obtain satisfactory performance of radial search for the 2MASS catalog. Our
system can also perform fast rectangular search. It is implemented using
techniques similar to those applied for radial search. Our way of
implementation enables a compact system and will give important hints for a
low-cost development of other huge catalog databases.Comment: 2011 PASP accepte
Identifications and SEDs of the detected sources from the AKARI Deep Field South
In order to find counterparts of the detected objects in the AKARI Deep Field
South (ADFS) in all available wavelengths, we searched public databases (NED,
SIMBAD and others). Checking 500 sources brighter than 0.0482 Jy in the AKARI
Wide-S band, we found 114 sources with possible counterparts, among which 78
were known galaxies. We present these sources as well as our first attempt to
construct spectral energy distributions (SEDs) for the most secure and most
interesting sources among them, taking into account all the known data together
with the AKARI measurements in four bands.Comment: 4 pages, 10 figures, To appear in: the proceedings of the conference
"AKARI, a light to illuminate the misty Universe", February 16-19 2009, Toky
Zoo-FISH in the European mole (Talpa europaea) detects all ancestral Boreo-Eutherian human homologous chromosome associations
Zoo-FISH with human whole-chromosome paint probes delineated syntenic association of human homologous chromosome segments 3-21, 14-15, 16-19, 4-8, 7-16 and 12-22 (twice) in the European mole (Talpa europaea, Talpidae, Eulipotyphla, Mammalia). These segment associations represent shared ancestral Boreo-Eutherian traits, half of which were previously not described for Eulipotyphla. The karyotype of the European mole acquired a minimum of 19 translocations and six inversions compared to the presumed Boreo-Eutherian ancestor. Copyright (c) 2006 S. Karger AG, Basel
Monolithic Ge:Ga Detector Development for SAFARI
We describe the current status and the prospect for the development of
monolithic Ge:Ga array detector for SAFARI. Our goal is to develop a 64x64
array for the 45 -- 110 um band, on the basis of existing technologies to make
3x20 monolithic arrays for the AKARI satellite. For the AKARI detector we have
achieved a responsivity of 10 A/W and a read-out noise limited NEP (noise
equivalent power) of 10^-17 W/rHz. We plan to develop the detector for SAFARI
with technical improvements; significantly reduced read-out noise with newly
developed cold read-out electronics, mitigated spectral fringes as well as
optical cross-talks with a multi-layer antireflection coat. Since most of the
elemental technologies to fabricate the detector are flight-proven, high
technical readiness levels (TRLs) should be achieved for fabricating the
detector with the above mentioned technical demonstrations. We demonstrate some
of these elemental technologies showing results of measurements for test
coatings and prototype arrays.Comment: To appear in Proc. Workshop "The Space Infrared Telescope for
Cosmology & Astrophysics: Revealing the Origins of Planets and Galaxies".
Eds. A.M. Heras, B. Swinyard, K. Isaak, and J.R. Goicoeche
Spatial Distributions of Cold and Warm Interstellar Dust in M101 Resolved with AKARI/Far-Infrared Surveyor (FIS)
The nearby face-on spiral galaxy M101 has been observed with the Far-Infrared
Surveyor (FIS) onboard AKARI. The far-infrared four-band images reveal fine
spatial structures of M101, which include global spiral patterns, giant HII
regions embedded in outer spiral arms, and a bar-like feature crossing the
center. The spectral energy distribution of the whole galaxy shows the presence
of the cold dust component (18 K) in addition to the warm dust component (55
K). The distribution of the cold dust is mostly concentrated near the center,
and exhibits smoothly distributed over the entire extent of the galaxy, whereas
the distribution of the warm dust indicates some correlation with the spiral
arms, and has spotty structures such as four distinctive bright spots in the
outer disk in addition to a bar-like feature near the center tracing the CO
intensity map. The star-formation activity of the giant HII regions that
spatially correspond to the former bright spots is found to be significantly
higher than that of the rest of the galaxy. The latter warm dust distribution
implies that there are significant star-formation activities in the entire bar
filled with molecular clouds. Unlike our Galaxy, M101 is a peculiar normal
galaxy with extraordinary active star-forming regions.Comment: 18 pages, 9 figures, accepted for publication in PASJ AKARI special
issu
CSIP - a Novel Photon-Counting Detector Applicable for the SPICA Far-Infrared Instrument
We describe a novel GaAs/AlGaAs double-quantum-well device for the infrared
photon detection, called Charge-Sensitive Infrared Phototransistor (CSIP). The
principle of CSIP detector is the photo-excitation of an intersubband
transition in a QW as an charge integrating gate and the signal amplification
by another QW as a channel with very high gain, which provides us with
extremely high responsivity (10^4 -- 10^6 A/W). It has been demonstrated that
the CSIP designed for the mid-infrared wavelength (14.7 um) has an excellent
sensitivity; the noise equivalent power (NEP) of 7x10^-19 W/rHz with the
quantum efficiency of ~2%. Advantages of the CSIP against the other highly
sensitive detectors are, huge dynamic range of >10^6, low output impedance of
10^3 -- 10^4 Ohms, and relatively high operation temperature (>2K). We discuss
possible applications of the CSIP to FIR photon detection covering 35 -- 60 um
waveband, which is a gap uncovered with presently available photoconductors.Comment: To appear in Proc. Workshop "The Space Infrared Telescope for
Cosmology & Astrophysics: Revealing the Origins of Planets and Galaxies".
Eds. A.M. Heras, B. Swinyard, K. Isaak, and J.R. Goicoeche
Dengue Vectors and their Spatial Distribution
The distribution of dengue vectors, Ae. aegypti and Ae. albopictus, is affected by climatic factors. In addition, since their life cycles are well adapted to the human environment, environmental changes resulting from human activity such as urbanization exert a great impact on vector distribution. The different responses of Ae. aegypti and Ae albopictus to various environments result in a difference in spatial distribution along north-south and urban-rural gradients, and between the indoors and outdoors. In the north-south gradient, climate associated with survival is an important factor in spatial distribution. In the urban-rural gradient, different distribution reflects a difference in adult niches and is modified by geographic and human factors. The direct response of the two species to the environment around houses is related to different spatial distribution indoors and outdoors. Dengue viruses circulate mainly between human and vector mosquitoes, and the vector presence is a limiting factor of transmission. Therefore, spatial distribution of dengue vectors is a significant concern in the epidemiology of the disease
Nationwide Investigation of the Pyrethroid Susceptibility of Mosquito Larvae Collected from Used Tires in Vietnam
Pyrethroid resistance is envisioned to be a major problem for the vector control program since, at present, there are no suitable chemical substitutes for pyrethroids. Cross-resistance to knockdown agents, which are mainly used in mosquito coils and related products as spatial repellents, is the most serious concern. Since cross-resistance is a global phenomenon, we have started to monitor the distribution of mosquito resistance to pyrethroids. The first pilot study was carried out in Vietnam. We periodically drove along the national road from the north end to the Mekong Delta in Vietnam and collected mosquito larvae from used tires. Simplified susceptibility tests were performed using the fourth instar larvae of Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus. Compared with the other species, Ae. aegypti demonstrated the most prominent reduction in susceptibility. For Ae. aegypti, significant increases in the susceptibility indices with a decrease in the latitude of collection points were observed, indicating that the susceptibility of Ae. aegypti against d-allethrin was lower in the southern part, including mountainous areas, as compared to that in the northern part of Vietnam. There was a significant correlation between the susceptibility indices in Ae. aegypti and the sum of annual pyrethroid use for malaria control (1998–2002). This might explain that the use of pyrethroids as residual treatment inside houses and pyrethroid-impregnated bed nets for malaria control is attributable to low pyrethroid susceptibility in Ae. aegypti. Such insecticide treatment appeared to have been intensively administered in the interior and along the periphery of human habitation areas where, incidentally, the breeding and resting sites of Ae. aegypti are located. This might account for the strong selection pressure toward Ae. aegypti and not Ae. albopictus
An electro-chemo-mechanical analysis of solid oxide fuel cell considering evolution of microstructure in porous electrode using phase-field method
For the numerical simulation of oxygen potential distributions in Solid Oxide
Fuel Cell (SOFC), the time-evolution of the anode microstructure is reflected in the
macroscopic electrical conductivities and the amount of triple-phase boundaries. Once the
oxygen potential distributions are determined, the time-variation of the reduction-induced
strains due to nonstoichiometry of oxide materials is calculated along with the thermal strains.
These strains cause the macroscopic stresses in mutually constrained components. Thus, the
capability of the proposed method is demonstrated in characterizing the aging degradation of
the macroscopic electro-chemo-mechanical behavior of SOFC that is caused by the Nisintering
in cermet microstructures during long-period control
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