525 research outputs found

    Laser ranging application to time transfer using geodetic satellite and to other Japanese space programs

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    Communications Research Laboratory (CRL) has been developing a laser time transfer system using a satellite laser ranging (SLR) system. We propose Japanese geodetic satellite 'AJISAI', launched in 1986 as a target satellite. The surface is covered not only with corner cube reflectors but also with mirrors. The mirrors are originally designed for observation of flushing solar light reflected by the separate mirrors while the satellite is spinning. In the experiment, synchronized laser pulses are transferred via specified mirror from one station to another while the satellite is up on the horizon to both stations. The system is based on the epoch timing ranging system with 40 ps ranging precision, connected together with UTC(CRL). Simulation study indicates that two stations at thousands of km distance from each other can be linked with signal strength of more than 10 photons and the distributed images of laser beam from AJISAI mirrors give many chances for two stations to link each other during a single AJISAI pass. Retro-reflector In Space for Advanced Earth Observation Satellite (ADEOS) and RendDezVous docking mission of Experimental Technology Satellite-7 (ETS-7) are briefly presented

    Estimation of Newtonian noise from KAGRA cooling system

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    KAGRA is the first km-scale gravitational wave detector to be constructed underground and employ cryogenics to cool down its test masses. While the underground location provides a quiet site with low seismic noise, the cooling infrastructure is known to generate large mechanical vibrations due to cryocooler operation and structural resonances of the cryostat. As cooling system components are relatively heavy and in close proximity to the test masses, oscillation of gravity force induced by their vibration, so-called Newtonian noise, could contaminate the detector sensitivity. In this paper, we use the results from vibration analysis of the KAGRA cryostat to estimate cooling system Newtonian noise in the 1-100 Hz frequency band. Our calculations show that, while this noise does not limit the current detector sensitivity or inspiral range, it will be an issue in the future when KAGRA improves its sensitivity. We conclude that KAGRA may need to implement Wiener filters to subtract this noise in the future

    Cloning of CRP2, a novel member of the cysteine-rich protein family with two repeats of an unusual LIM/double zinc-finger motif

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    AbstractThe cDNA coding for a novel member of the cysteine-rich protein family was isolated from a rat brain cDNA library. It encodes a protein, denoted cysteine-rich protein 2 (CRP2), of 208 amino acid residues containing two tandem repeats of an unusual LIM/double zinc-finger-like motif. The ubiquitous tissue distribution and high level of expression of CRP2 mRNA suggest an important role for CRP2 in cell functions

    Wetting hysteresis induces effective unidirectional water transport through a fluctuating nanochannel

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    We propose a water pump that actively transports water molecules through nanochannels. Spatially asymmetric thermal fluctuations imposed on the channel radius cause unidirectional water flow without osmotic pressure, which can be attributed to hysteresis in the cyclic transition between the wetting/drying states. We show that the water transport depends on fluctuations, such as white, Brownian, and pink noises. Because of the high-frequency components in white noise, fast switching of open and close states inhibits channel wetting. Conversely, pink and Brownian noises generate high-pass filtered net flow. Brownian fluctuation leads to a faster water transport rate, whereas pink noise has a higher capability to overcome osmotic pressure in the opposite direction. A trade-off relationship exists between the resonant frequency of the fluctuation and the flow amplification. The proposed pump can be considered as an analogy for the reversed Carnot cycle, which is the upper limit on the energy conversion efficiency

    Evaluation of heat extraction through sapphire fibers for the GW observatory KAGRA

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    Currently, the Japanese gravitational wave laser interferometer KAGRA is under construction in the Kamioka mine. As one main feature, it will employ sapphire mirrors operated at a temperature of 20K to reduce the impact from thermal noise. To reduce seismic noise, the mirrors will also be suspended from multi-stage pendulums. Thus the heat load deposited in the mirrors by absorption of the circulating laser light as well as heat load from thermal radiation will need to be extracted through the last suspension stage. This stage will consist of four thin sapphire fibers with larger heads necessary to connect the fibers to both the mirror and the upper stage. In this paper, we discuss heat conductivity measurements on different fiber candidates. While all fibers had a diameter of 1.6mm, different surface treatments and approaches to attach the heads were analyzed. Our measurements show that fibers fulfilling the basic KAGRA heat conductivity requirement of κ\kappa\geq 5000W/m/K at 20K are technologically feasible.Comment: 11 pages, 4 figure

    Molecular Clouds as Cosmic Ray Laboratories

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    We will here discuss how the gamma-ray emission from molecular clouds can be used to probe the cosmic ray flux in distant regions of the Galaxy and to constrain the highly unknown cosmic ray diffusion coefficient. In particular we will discuss the GeV to TeV emission from runaway cosmic rays penetrating molecular clouds close to young and old supernova remnants and in molecular clouds illuminated by the background cosmic ray flux.Comment: to appear on Proceedings of 25th Texas Symposium on Relativistic Astrophysic

    Immunohistochemical Analysis of CXCR4 Expression in Fibrohistiocytic Tumors

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    Functional chemokine receptors are expressed in many malignant tumors. These receptors promote tumor growth and metastasis in response to endogenous chemokines. We analyzed the expression of CXCR4, CCR6 and CCR7 in fibrohistiocytic tumors, including dermatofibrosarcoma protuberance (DFSP), malignant fibrous histiocytoma (MFH), dermatofibroma (DF) using immunohistochemistry. We also investigated the relationship between CXCR4 and CD34, the latter of which is an immunohistochemical marker for DFSP. We observed a higher expression of CXCR4 in DFSP and MFH as compared with DF. Interestingly, a significantly higher expression of CXCR4 was detected in relapsed DFSP than in non-relapsed DFSP, but no significant differences were detected between non-relapsed DFSP and DFSP with CD34 immunostaining. Moreover, MFH had strong immunoreactivity for CXCR4, CCR6 and CCR7. These findings suggest that the assessment of CXCR4 immunoreactivity in fibrohistiocytic tumors is a useful tool for predicting tumor aggressiveness

    Discovery of Molecular Loop 3 in the Galactic Center: Evidence for a Positive-Velocity Magnetically Floated Loop towards L=355359L=355^\circ-359^\circ

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    We have discovered a molecular dome-like feature towards 355l359355^{\circ} \leq l \leq 359^{\circ} and 0b20^{\circ} \leq b \leq 2^{\circ}. The large velocity dispersions of 50--100 km s1^{-1} of this feature are much larger than those in the Galactic disk and indicate that the feature is located in the Galactic center, probably within 1\sim1 kpc of Sgr A^{*}. The distribution has a projected length of 600\sim600 pc and height of 300\sim300 pc from the Galactic disk and shows a large-scale monotonic velocity gradient of 130\sim130 km s 1^{-1} per 600\sim600 pc. The feature is also associated with HI gas having a more continuous spatial and velocity distribution than that of 12^{12}CO. We interpret the feature as a magnetically floated loop similar to loops 1 and 2 and name it "loop 3". Loop 3 is similar to loops 1 and 2 in its height and length but is different from loops 1 and 2 in that the inner part of loop 3 is filled with molecular emission. We have identified two foot points at the both ends of loop 3. HI, 12^{12}CO and 13^{13}CO datasets were used to estimate the total mass and kinetic energy of loop 3 to be \sim3.0 \times 10^{6} \Mo and 1.7×1052\sim1.7 \times 10^{52} ergs. The huge size, velocity dispersions and energy are consistent with the magnetic origin the Parker instability as in case of loops 1 and 2 but is difficult to be explained by multiple stellar explosions. We argue that loop 3 is in an earlier evolutionary phase than loops 1 and 2 based on the inner-filled morphology and the relative weakness of the foot points. This discovery indicates that the western part of the nuclear gas disk of 1\sim1 kpc radius is dominated by the three well-developed magnetically floated loops and suggests that the dynamics of the nuclear gas disk is strongly affected by the magnetic instabilities.Comment: 30 pages, 10 figures. High resolution figures are available at http://www.a.phys.nagoya-u.ac.jp/~motosuji/fujishita09_figs
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