20 citations · 161 across the 23 of their papers we have counts for
23 papers
Odd-parity ringdown gravitational waves of a spherically symmetric black hole with perfect fluid accretion
Rikuto Ohashi, Yasutaka Koga, Hiroyuki Nakano +2
The ringdown waves from a black hole offer a clean probe of strong-field gravity, but a matter distribution that may be present around a realistic black hole renders the background…
Urban Reconstruction and Population Redistribution: Evidence from Tokyo after the Great Kanto Earthquake
Kota Ogasawara
This study examines the impact of the 1923 Great Kanto Earthquake on population distribution within Tokyo City. The earthquake triggered massive fires that devastated nearly half o…
Risk-coping Behaviors in Metropolis: Evidence from Working-class Households in Prewar Tokyo
Kota Ogasawara
I analyze the risk-coping strategies of factory-worker households in early twentieth-century Tokyo. I digitized a unique daily longitudinal household budget survey conducted in Tsu…
Technology, Institution, and Regional Growth: Evidence from Mineral Mining Industry in Industrializing Japan
Kota Ogasawara
Coal mining was an influential economic activity in interwar Japan. Initially, coal mines employed both men and women in the pits. However, the introduction of labor-saving technol…
Photon escape in the extremal Kerr black hole spacetime
Kota Ogasawara, Takahisa Igata
We consider necessary and sufficient conditions for photons emitted from an arbitrary spacetime position of the extremal Kerr black hole to escape to infinity. The radial equation…
Photon emission from inside the innermost stable circular orbit
Takahisa Igata, Kazunori Kohri, Kota Ogasawara
We consider a situation where a light source orbiting the innermost stable circular orbit (ISCO) of the Kerr black hole is gently falling from the marginally stable orbit due to an…
The Impacts of the Gender Imbalance on the Marriage Market: Evidence from World War II in Japan
Kota Ogasawara, Erika Igarashi
This study uses the unprecedented changes in the sex ratio due to the losses of men during World War II to identify the impacts of the gender imbalance on marriage market outcomes…
Complete classification of photon escape in the Kerr black hole spacetime
Kota Ogasawara, Takahisa Igata
We consider necessary and sufficient conditions for photons emitted from the vicinity of a Kerr black hole horizon to escape to infinity. The radial equation of motion determines n…
Pandemic Influenza and Gender Imbalance: Mortality Selection before Births
Kota Ogasawara
This study uses data from the 1918-1920 influenza pandemic in Japan along with newly digitized and complete census records on births and infant deaths to analyze mortality selectio…
Escape probability of a photon emitted near the black hole horizon
Kota Ogasawara, Takahisa Igata, Tomohiro Harada +1
We investigate the escape of photons from the vicinity of the horizon to infinity in the Kerr-Newmann black hole spacetime. We assume that a light source is at rest in a locally no…
Observability of the innermost stable circular orbit in a near-extremal Kerr black hole
Takahisa Igata, Keisuke Nakashi, Kota Ogasawara
We consider the escape probability of a photon emitted from the innermost stable circular orbit (ISCO) of a rapidly rotating black hole. As an isotropically emitting light source o…
Particulate Air Pollution, Birth Outcomes, and Infant Mortality: Evidence from Japan's Automobile Emission Control Law of 1992
Tatsuki Inoue, Nana Nunokawa, Daisuke Kurisu +1
This study investigates the impacts of the Automobile NOx Law of 1992 on ambient air pollutants and fetal and infant health outcomes in Japan. Using panel data taken from more than…
Effect of the self-gravity of shells on a high energy collision in a rotating Bañados-Teitelboim-Zanelli spacetime
Kota Ogasawara, Naoki Tsukamoto
We consider a collision of two dust thin shells with a high center-of-mass (CM) energy including their self-gravity in a Bañados-Teitelboim-Zanelli (BTZ) spacetime. The shells divi…
Consumption smoothing in the working-class households of interwar Japan
Kota Ogasawara
I analyze factory worker households in the early 1920s in Osaka to examine idiosyncratic income shocks and consumption. Using the household-level monthly panel dataset, I find that…
Persistence of Natural Disasters on Children's Health: Evidence from the Great Kanto Earthquake of 1923
Kota Ogasawara
This study uses a catastrophic earthquake in 1923 to analyse the long-term effects of a natural disaster on children's health. I find that fetal exposure to Japan's Great Kanto Ear…
Chain effects of clean water: The Mills-Reincke phenomenon in early twentieth-century Japan
Tatsuki Inoue, Kota Ogasawara
This study explores the validity of chain effects of clean water, which are known as the "Mills-Reincke phenomenon," in early twentieth-century Japan. Recent studies have reported…
Particle collision with an arbitrarily high center-of-mass energy near a Bañados-Teitelboim-Zanelli black hole
Naoki Tsukamoto, Kota Ogasawara, Yungui Gong
We consider a particle collision with a high center-of-mass energy near a Bañados-Teitelboim-Zanelli (BTZ) black hole. We obtain the center-of-mass energy of two general colliding…
Escape probability of the super-Penrose process
Kota Ogasawara, Tomohiro Harada, Umpei Miyamoto +1
We consider a head-on collision of two massive particles that move in the equatorial plane of an extremal Kerr black hole, which results in the production of two massless particles…
Bayesian Nonparametric Instrumental Variable Regression Approach to Quantile Inference
Genya Kobayashi, Kota Ogasawara
This study extends the Bayesian nonparametric instrumental variable regression model to determine the structural effects of covariates on the conditional quantile of the response v…
Consistent analytic approach to the efficiency of collisional Penrose process
Tomohiro Harada, Kota Ogasawara, Umpei Miyamoto
We propose a consistent analytic approach to the efficiency of collisional Penrose process in the vicinity of a maximally rotating Kerr black hole. We focus on a collision with arb…
High efficiency of collisional Penrose process requires heavy particle production
Kota Ogasawara, Tomohiro Harada, Umpei Miyamoto
The center-of-mass energy of two particles can become arbitrarily large if they collide near the event horizon of an extremal Kerr black hole, which is called the Baa…
Empirical Uncertain Bayes Methods in Area-level Models
Shonosuke Sugasawa, Tatsuya Kubokawa, Kota Ogasawara
Random effects model can account for the lack of fitting a regression model and increase precision of estimating area-level means. However, in case that the synthetic mean provides…
Small Area Estimation with Spatially Varying Natural Exponential Families
Shonosuke Sugasawa, Yuki Kawakubo, Kota Ogasawara
Two-stage hierarchical models have been widely used in small area estimation to produce indirect estimates of areal means. When the areas are treated exchangeably and the model par…