Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

病院勤務の看護師の職務キャリア意識と職業的アイデンティティの性差の検討

There has been a consistent increase in the number of male nurses in Japan. Male nurses who work with many female nurses have gender-specific distress. We examined the differences in occupational career assessments and professional identities of male and female nurses according to demographic factors. Our study was focused on the proportion of males to females in the occupational environment. A total of 229 male and female nurses completed the questionnaire used in the analysis. We evaluated demographic factors by t-tests and chi-squared tests, and applied Tukey’s multiple comparisons to professional identity scores and career assessment scores. Two-way ANOVA was used in evaluating the impact of the proportion of men to women in occupational environments to occupational career assessments and professional identities according to gender. The mean age of the nurse participants was about 36 years old. Fifty percent were female nurses. Occupational career assessments were higher for male nurses. Male nurses seem to prefer their nursing job as a career. Professional identity was higher for female nurses: nursing could be considered a subjective sense of awareness of “myself as a nurse” for them. There were no significant main or interaction effects of gender and the proportion of nurses in one’s own department to occupational career assessment and professional identity for nurses. As has been reported, professional identity may be highly relevant to female nurses, and occupational career assessment may be highly relevant to male nurses

Cu Species Incorporated into Amorphous ZrO₂ with High Activity and Selectivity in CO₂‑to-Methanol Hydrogenation

We prepared Cu/a-ZrO₂ (a-ZrO₂: amorphous ZrO₂), Cu/m-ZrO₂ (m-ZrO₂: monoclinic ZrO₂), Cu/a-ZrO₂/KIT-6, and Cu/t-ZrO₂/KIT-6 (t-ZrO₂: tetragonal ZrO₂) by a simple impregnation method and examined the effect of the ZrO₂ phase on CO₂-to-methanol hydrogenation. We discovered a-ZrO₂-containing catalysts with high activity and selectivity in CO₂-to-methanol hydrogenation. Next, we focused on Cu species formation on the above-described catalysts. While pure CuO was observed on Cu/m-ZrO₂ and Cu/t-ZrO₂/KIT-6, copper-zirconium mixed oxide (Cu_<i>x</i>Zr_<i>y</i>O_<i>z</i>), not pure CuO, was formed on Cu/a-ZrO₂ and Cu/a-ZrO₂/KIT-6, as evidenced by X-ray absorption spectroscopy (XAS) and the powder color. After reducing a-ZrO₂-containing catalysts with H₂ at 300 °C, we observed highly dispersed Cu nanoparticles in close contact with a-ZrO₂ (or Cu_<i>x</i>Zr_<i>y</i>O_<i>z</i>). In addition, methanol vapor sorption revealed that methanol adsorbed more weakly on a-ZrO₂ than on m-ZrO₂. Therefore, the high dispersion of Cu species and weak adsorption of methanol led to high activity and selectivity in CO₂-to-methanol hydrogenation