6,689 research outputs found

    Development of 2MASS Catalog Server Kit

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    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

    Performance and loads data from an outdoor hover test of a Lynx tail rotor

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    A Lynx tail rotor was tested in hover at the Outdoor Aerodynamic Research Facility at NASA Ames Research Center. The test objectives were to measure the isolated rotor performance to provide a baseline for subsequent testing, and to operate the rotor throughout the speed and collective envelope before testing in the NFAC 40- by 80-Foot Wind Tunnel. Rotor forces and blade bending moments were measured at ambient wind conditions from zero to 6.23 m/sec. The test envelope was limited to rotor speeds of 1550 to 1850 rpm and minus 13 deg to plus 20 deg of blade collective pitch. The isolated rotor performance and blade loads data are presented

    Multi-field open inflation model and multi-field dynamics in tunneling

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    We consider a multi-field open inflation model, in which one of the fields dominates quantum tunneling from a false vacuum while the other field governs slow-roll inflation within the bubble nucleated from false vacuum decay. We call the former the tunneling field and the latter the inflaton field. In the limit of a negligible interaction between the two fields, the false vacuum decay is described by a Coleman-De Luccia instanton. Here we take into account the coupling between the two fields and construct explicitly a multi-field instanton for a simple quartic potential model. We also solve the evolution of the scalar fields within the bubble. We find our model realizes open inflation successfully. This is the first concrete, viable model of open inflation realized with a simple potential. We then study the effect of the multi-field dynamics on the false vacuum decay, specifically on the tunneling rate. We find the tunneling rate increases in general in comparison with the single field case, though the increase is small unless the inflaton affects the instanton solution substantially.Comment: 13 pages, 4 figure

    In Vivo oocyte maturation and ovulation in females and spermiation in males of hybrid sturgeon, bester

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    Bester, a hybrid sturgeon (Huso huso L. females ´ Acipenser ruthenus L. males), neither spermiate nor ovulate in the captivity. Thirteen-year-old adult male and female bester were injected with LH-RHa (0.1-0.3 mg/kg B.W.) intramuscularly and spawning status of the treated fish was checked 24-48 hours later. Additionally, changes in serum levels of DHP in both the responded and the non-responded individuals were monitored 0, 1, 3, 6, 9, 12, 24, 48 and 72 hours after treatment. Between 70-100 percent of the LR-RHa injected males individuals, and 11-40 percent of the females spawned 24-48 hours after the treatment; the rest did not respond to the injection. In the responded males, 3-9 hours after the treatment, serum levels of DHP increased; while in the females it occurred first after 12-24 hours. In contrast, during the same period, serum levels of DHP remained low in all non-responded individuals. The present study indicated that using 0.1-1.3 mg/kg B. W. of LH-RHa can induce oocyte maturation and ovulation in the females and spermiation in the males cultured bester. The results suggested additionally DHP as an appropriated steroid that could be used in the final maturation stage of the gonads

    Structural transformation and magnetic competition in Yb(Mn1-xFex)O3

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    Structural and magnetic properties of the Yb(Mn1−xFex)O3 (0⩽x⩽1) system have been systematically investigated. Initial samples were prepared via a sol-gel method. A pure hexagonal phase was only obtained for samples with x⩽0.5. With high-pressure annealing, a pure orthorhombic perovskite phase was achieved for all the compositions. The Fe57 Mössbauer spectrum for x=0.5 shows that only Fe3+ ions exist in the system; there was no evidence of chemical inhomogeneities. With increasing x, the Néel temperature TN increases for both hexagonal and orthorhombic phases. The orthorhombic Yb(Mn0.5Fe0.5)O3 shows an interesting weak ferromagnetic state in the temperature range of 239–298K, the ferromagnetism disappearing abruptly on cooling below Tt=239K. The transition at Tt appears to be a reorientation of the spin axis of a type-G antiferromagnetic order from the orthorhombic a axis to the b axis in the (010) plane.Peer reviewe

    Discovery of X rays from Class 0 protostar candidates in OMC-3

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    We have observed the Orion Molecular Clouds 2 and 3 (OMC-2 and OMC-3) with the Chandra X-ray Observatory (CXO). The northern part of OMC-3 is found to be particularly rich in new X-ray features; four hard X-ray sources are located in and along the filament of cloud cores. Two sources coincide positionally with the submmmm-mmmm dust condensations of MMS 2 and 3 or an outflow radio source VLA 1, which are in a very early phase of star formation. The X-ray spectra of these sources show an absorption column of (1-3) x 10^23 H cm-2. Assuming a moderate temperature plasma, the X-ray luminosity in the 0.5-10 keV band is estimated to be ~10^30 erg s^-1 at a distance of 450 pc. From the large absorption, positional coincidence and moderate luminosity, we infer that the hard X-rays are coming from very young stellar objects embedded in the molecular cloud cores. We found another hard X-ray source near the edge of the dust filament. The extremely high absorption of 3 x 10^23 H cm^-2 indicates that the source must be surrounded by dense gas, suggesting that it is either a YSO in an early accretion phase or a Type II AGN (e.g. a Seyfert 2), although no counterpart is found at any other wavelength. In contrast to the hard X-ray sources, soft X-ray sources are found spread around the dust filaments, most of which are identified with IR sources in the T Tauri phase.Comment: 9 pages, To be appeared in ApJ v554 n2 Jun 20, 2001 issue, related press release is available at http://science.psu.edu/alert/Tsuboi11-2000.htm, Figure 1 and figure 2 with the best resolution is available at ftp.astro.psu.edu/pub/tsuboi/OMC/010205

    Experimental analysis of sample-based maps for long-term SLAM

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    This paper presents a system for long-term SLAM (simultaneous localization and mapping) by mobile service robots and its experimental evaluation in a real dynamic environment. To deal with the stability-plasticity dilemma (the trade-off between adaptation to new patterns and preservation of old patterns), the environment is represented at multiple timescales simultaneously (5 in our experiments). A sample-based representation is proposed, where older memories fade at different rates depending on the timescale, and robust statistics are used to interpret the samples. The dynamics of this representation are analysed in a five week experiment, measuring the relative influence of short- and long-term memories over time, and further demonstrating the robustness of the approach

    3',5'-Cyclic Adenosine Monophosphate- and Ca2+-Calmodulin-Dependent Endogenous Protein Phosphorylation Activity in Membranes of the Bovine Chromaffin Secretory Vesicles: Identification of Two Phosphorylated Components as Tyrosine Hydroxylase and Protein Kinase Regulatory Subunit Type II

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    Abstract: Membranes of the secretory vesicles from bovine adrenal medulla were investigated for the presence of the endogenous protein phosphorylation activity. Seven phosphoprotein bands in the molecular weight range of 250,000 to 30,000 were observed by means of the sodium dodecyl sulphate electrophoresis and autoradiography. On the basis of the criteria of molecular weight, selective stimulation of the phosphorylation by cyclic AMP (as compared with cyclic GMP) and immunoprecipitation by specific antibodies, band 5 (molecular weight 60,300) was found to represent the phosphorylated form of the secretory vesicle-bound tyrosine hydroxylase. The electrophoretic mobility, the stimulatory and inhibitory effects of cyclic AMP in presence of Mg2+ and Zn,2+ respectively, and immunoreactivity toward antibodies showed band 6 to contain two forms of the regulatory subunits of the type II cyclic AMP-dependent protein kinase, distinguishable by their molecular weights (56,000 and 52,000, respectively). Phosphorylation of band 7 (molecular weight 29,800) was stimulated about 2 to 3 times by Ca2+ and calmodulin in the concentration range of both agents believed to occur in the secretory tissues under physiological conditions

    Comparison and Mapping Facilitate Relation Discovery and Predication

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    Relational concepts play a central role in human perception and cognition, but little is known about how they are acquired. For example, how do we come to understand that physical force is a higher-order multiplicative relation between mass and acceleration, or that two circles are the same-shape in the same way that two squares are? A recent model of relational learning, DORA (Discovery of Relations by Analogy; Doumas, Hummel & Sandhofer, 2008), predicts that comparison and analogical mapping play a central role in the discovery and predication of novel higher-order relations. We report two experiments testing and confirming this prediction

    Geometrical quadrupolar frustration in DyB4_4

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    Physical properties of DyB4_4 have been studied by magnetization, specific heat, and ultrasonic measurements. The magnetic entropy change and the ultrasonic properties in the intermediate phase II indicate that the degeneracy of internal degrees of freedom is not fully lifted in spite of the formation of magnetic order. The ultrasonic attenuation and the huge softening of C44C_{44} in phase II suggests existence of electric-quadrupolar (orbital) fluctuations of the 4ff-electron. These unusual properties originate from the geometrical quadrupolar frustration.Comment: 4 pages, 4 figures, accepted for publication in Journal of the Physical Society of Japa
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