Tokyo City University

The Contact Frontier in Galactic Civilization Networks: Radial Structure and the Galactic Habitable Zone

The probability of interstellar contact depends not only on the abundance of technological civilizations but also on their spatial connectivity. Treating civilizations as nodes linked whenever their separation is smaller than the distance a signal travels within a communicative l...

Lifetime Distributions in Galactic Civilization Networks: A Hierarchy of Moments and Connectivity Thresholds

The Drake equation uses only the mean lifetime of a communicating civilization. Do contact and connectivity depend on the mean alone? Here the single lifetime and communication range of earlier work become a joint distribution at fixed mean. Abundance depends on the first moment...

Hour-scale response of low-Earth-orbit satellite altitude to extreme geomagnetic storms revealed by the NinjaSat CubeSat during the 2024 solar maximum

Abstract Extreme geomagnetic storms accelerate low-Earth-orbit satellite decay by inflating the thermosphere, yet the hour-scale pathway from solar-wind energy to atmospheric heating is poorly understood. Using the GNSS receiver of the NinjaSat CubeSat ( $$\sim 500$$ km, $$97^\ci...

Practical robust loop-shaping design method for triple-stage HDD actuator control under stroke constraints in data-center storage applications

With the continuous growth of data storage demand, precise and stable magnetic-head positioning in hard disk drives (HDDs) remains essential. This paper proposes a disturbance-rejection-oriented control design for triple-stage actuator (TSA) systems. The approach employs Bode-plo...

Pressure-Induced Interplay between Heavy-Fermion and Mn-Derived Magnetic States in CeMnSi

We investigated pressure effects on the nontrivial heavy-fermion antiferromagnet CeMnSi by means of electrical resistivity (ρ) and powder X-ray diffraction. With increasing pressure, the antiferromagnetic order of Mn (T N ∼ 240 K at ambient pressure) is rapidly suppressed and dis...

P1.114. Endoscopic Diagnosis of Esophageal Cancer Using Ultra-High Magnification Endocytoscopy

Abstract Topic Esophageal Cancer: New Diagnostic Modalities (Including PET, PET-CT, New Tracers) Background Background Ultra-high magnification endoscopic observation using endocytoscopy (EC) enables cellular-level visualization and allows in vivo assessment comparable to histopa...

Derivation of human post-mitotic cardiomyocytes from tetraploid iPSCs

Human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iPS-CMs) have great potential in regenerative medicine. However, iPS-CMs are immature and resemble fetal cardiomyocytes, restricting their application. Fetal cardiomyocytes in the human heart are diploid and proli...

Exergy analysis on daylighting with a single-paned glass window and PV-based electric lighting

This study aims to evaluate two representative pathways for utilizing solar radiation in a building for indoor lighting using exergy analysis: (1) direct daylight utilization through a window system and (2) indirect utilization through electric lighting powered by photovoltaic (P...

Molecular dynamics study on anisotropic water cluster formation in polyethylene: A fundamental perspective on water tree initiation

The microscopic mechanisms of water tree inception in polymeric insulating materials remain a critical challenge for high-voltage engineering. In this study, molecular dynamics simulations were employed to investigate the structural and kinetic responses of water nanoclusters in...

A hydro-mechanical mechanism for cyclic ratcheting of embedded cantilever retaining walls in saturated sand

Saturated backfills behind embedded cantilever walls deform through coupled hydro-mechanical processes that pseudo-static methods cannot capture. Three 40 g dynamic centrifuge tests are presented to isolate how the pre-seismic static state, set by wall flexural stiffness, togethe...