Parametrically Excited Vibration with External Constant Load and Damping

The vibrations of gears can be expressed by differential equations of parametrically excited vibrations. In this paper, the stabilities of parametrically excited vibrations of the MeiBner and Mathieu types (the former expresses the torsional vibrations of spur gears and the latter expresses those of helical gears) and their vibrational characteristics in the stable region are theoretically investigated. Through this investigation, the effects of the helix angle and the damping factor on the vibrations of gears are made clear. The vibrations of helical gears are smaller than those of spur gears. And the vibrations of helical gears with a large helix angle are smaller than those with a small helix angle. When the damping factor ζ increases, the unstable region decreases, and the peak levels of vibrations decrease remarkably, although the amplitude at the other region does not decrease. When we drive a pair of gears at a speed whose meshing frequency is two times faster than the natural frequency of the gearing system, the gears with a small damping have a very large vibration, but the gears with a large damping rotate smoothly

3-D Kinematics of Water Masers in the W51A Region

We report proper motion measurements of water masers in the massive-star forming region W51A and the analyses of the 3-D kinematics of the masers in three maser clusters of W51A (W51 North, Main, and South). In W~51 North, we found a clear expanding flow that has an expansion velocity of ~70 km/s and indicates deceleration. The originating point of the flow coincides within 0.1 as with a silicon-monoxide maser source near the HII region W~51d. In W51 Main, no systematic motion was found in the whole velocity range (158 km/s =< V(lsr) =< -58 km/s) although a stream motion was reported previously in a limited range of the Doppler velocity (54 km/s =< V(lsr) =< 68 kms). Multiple driving sources of outflows are thought to explain the kinematics of W51 Main. In W51 South, an expansion motion like a bipolar flow was marginally visible. Analyses based on diagonalization of the variance-covariance matrix of maser velocity vectors demonstrate that the maser kinematics in W51 North and Main are significantly tri-axially asymmetric. We estimated a distance to W51 North to be 6.1 +/- 1.3 kpc on the basis of the model fitting method adopting a radially expanding flow.Comment: 20 pages, 8 figures, 8 tables, appear in the NRO report No. 564 (ftp://ftp.nro.nao.ac.jp/nroreport/PASJ-W51.pdf) and will appear in Publ. Astron. Soc. Japan, Vol. 54, No. 5 (10/25 issue

VLBI Monitoring Observations of Water Masers Around the Semi-Regular Variable Star R Crateris

We monitored water-vapor masers around the semi-regular variable star R Crateris with the Japanese VLBI Network (J-Net) at the 22 GHz band during four epochs with intervals of one month. The relative proper motions and Doppler-velocity drifts of twelve maser features were measured. Most of them existed for longer than 80 days. The 3-D kinematics of the features indicates a bipolar expanding flow. The major axis of the asymmetric flow was estimated to be at P.A. = 136 degrees. The existence of a bipolar outflow suggests that a Mira variable star had already formed a bipolar outflow. The water masers are in a region of apparent minimum radii of 1.3 x 10^12 m and maximum radii of 2.6 x 10^12 m, between which the expansion velocity ranges from 4.3 to 7.4 km/s. These values suggest that the water masers are radially accelerated, but still gravitationally bound, in the water-maser region. The most positive and negative velocity-drifting features were found relatively close to the systemic velocity of the star. We found that the blue-shifted features are apparently accelerated and the red-shifted apparently decelerated. The acceleration of only the blue-shifted features seems to be consistent with that of the expanding flow from the star.Comment: 15 pages, 5 figures, Accepted for publication in PASJ (2001), preprint can be obtained via WWW on http://www.nro.nao.ac.jp/library/report/list.htm

VLBI Astrometry of the Semiregular Variable RX Bootis

We present distance measurement of the semiregular variable RX Bootis (RX Boo) with its annual parallax. Using the unique dual-beam system of the VLBI Exploration of Radio Astrometry (VERA) telescope, we conducted astrometric observations of a water maser spot accompanying RX Boo referred to the quasar J1419+2706 separated by 1.69 degrees from RX Boo. We have measured the annual parallax of RX Boo to be 7.31 +/- 0.50 mas, corresponding to a distance of 136 +10/-9 pc, from the one-year monitoring observation data of one maser spot at VLSR = 3.2 km/s. The distance itself is consistent with the one obtained with Hipparcos. The distance uncertainty is reduced by a factor of two, allowing us to determine the stellar properties more accurately. Using our distance, we discuss the location of RX Boo in various sequences of Period-Luminosity (PL) relations. We found RX Boo is located in the Mira sequence of PL relation. In addition, we calculated the radius of photosphere and the mass limitation of RX Boo and discussed its evolutionary status.Comment: 8 pages, 4figure

Participation in the Setouchi Triennale and the Health of Residents in Naoshima: A Cross-Sectional Study

Arts festivals have become increasingly popular in various parts of Japan in recent years. The purpose of this study was to investigate the relationships between arts festival activities participation at the Setouchi Triennale and the health of residents in the town of Naoshima. This was a cross-sectional study. Questionnaires were distributed to all residents of Naoshima who were 20 years old or older (n=2,588). We analyzed responses from 708 people. The associations between arts festival activities participation and health (measured by self-rated health) were analyzed using logistic regression analysis as the primary outcome. Kessler’s psychological distress scale scores were also analyzed in the same manner as the primary outcome. The participating group had an adjusted odds ratio of 1.86 (95% confidence interval: 1.03-3.33) for higher self-rated health compared with those who did not participate. Kessler’s psychological distress scale results showed that the participating group had an adjusted odds ratio of 3.23 (95% confidence interval: 1.19-8.81) for lower psychological distress compared with those who did not participate. In conclusion, arts festival activities participation was associated with higher self-rated health and lower psychological distress. However, caution must be taken in regard to generalizability and causality when interpreting these results

Does Participation in the Setouchi Triennale Foster Social Capital? : A Cross-Sectional Study

This study examined whether participation in an art project was associated with higher social capital (SC). We conducted a questionnaire survey from November 2021 to March 2022 among residents aged 20 years or older of Naoshima, an island in Kagawa Prefecture, Japan. Before the survey, the Setouchi Triennale had been held on Naoshima four times, starting in 2010. We calculated propensity scores for Triennale participation and performed propensity score matching. We then compared cognitive and structural SC by Triennale participation and found significant differences, respectively. We adopted a conditional ordered logistic regression analysis with propensity score matching for cognitive or structural SC, and found adjusted odd ratios of 2.913 (95%CI, 1.846-4.596) for cognitive SC and 4.535 (95%CI, 2.839-7.244) for structural SC. Our findings suggest that Triennale participation enhanced the cognitive aspect of SC while also building structural SC

Identification of a mammalian vesicular polyamine transporter

Spermine and spermidine act as neuromodulators upon binding to the extracellular site(s) of various ionotropic receptors, such as N-methyl-d-aspartate receptors. To gain access to the receptors, polyamines synthesized in neurons and astrocytes are stored in secretory vesicles and released upon depolarization. Although vesicular storage is mediated in an ATP-dependent, reserpine-sensitive fashion, the transporter responsible for this process remains unknown. SLC18B1 is the fourth member of the SLC18 transporter family, which includes vesicular monoamine transporters and vesicular acetylcholine transporter. Proteoliposomes containing purified human SLC18B1 protein actively transport spermine and spermidine by exchange of H+. SLC18B1 protein is predominantly expressed in the hippocampus and is associated with vesicles in astrocytes. SLC18B1 gene knockdown decreased both SLC18B1 protein and spermine/spermidine contents in astrocytes. These results indicated that SLC18B1 encodes a vesicular polyamine transporter (VPAT)

Annual Parallax Distance to the K-type star system IRAS 22480+6002 measured with VERA

We present the astrometric VLBI observations of water masers associated with IRAS 22480+6002 (IRC+60370, hereafter I22480) with the VLBI Exploration of Radio Astrometry (VERA). The stellar type of I22480 looks unusual as a stellar maser source and has been debated since the 1970s. We successfully determined the annual parallax of a group of the water maser spots, pi=0.400+/-0.025 mas, corresponding to a distance to I22480 of D=2.50 /+0.17/-0.15 kpc. This suggests that the estimated bolometric luminosity of I22480 should be revised to 35 000 L_sun, favoring a K-type supergiant rather than an RV Tau-type variable star previously suggested. Although the spectral type is unusual as a stellar maser source, the internal motions of the water maser features suggest that the water masers are associated with the circumstellar envelope of this star. Taking into account a possible stellar motion with respect to the maser feature motions, we derived a secular proper motion of I22480, (mu_alpha, mu_delta)=(-2.58+/-0.33, -1.91+/-0.17) [mas yr^-1]. The derived motion of I22480 in the Milky Way has a deviation by ~ -30 km/s in the galactic azimuthal direction from a circular motion estimated from the galactocentric distance to I22480 and assumption of a flat Galactic rotation curve. This peculiar motion is still comparable to those typically seen in the water maser sources located in the Perseus spiral arm. Taking into account the peculiar motion and the proximity to the Galactic midplane (z ~60 pc), I22480 may be a member of the Galactic thin disk.Comment: 11 pages, 7 figures, accepted by PASJ (issue on vol. 65, No.1). Figure formats were correcte