Kōchi University

About: Kōchi University is a education organization based out in Kochi, Japan. It is known for research contribution in the topics: Population & Zircon. The organization has 5314 authors who have published 10056 publications receiving 204869 citations. The organization is also known as: Kōchi Daigaku.

Temperature limits to deep subseafloor life in the Nankai Trough subduction zone

Abstract: Microorganisms in marine subsurface sediments substantially contribute to global biomass. Sediments warmer than 40°C account for roughly half the marine sediment volume, but the processes mediated by microbial populations in these hard-to-access environments are poorly understood. We investigated microbial life in up to 1.2-kilometer-deep and up to 120°C hot sediments in the Nankai Trough subduction zone. Above 45°C, concentrations of vegetative cells drop two orders of magnitude and endospores become more than 6000 times more abundant than vegetative cells. Methane is biologically produced and oxidized until sediments reach 80° to 85°C. In 100° to 120°C sediments, isotopic evidence and increased cell concentrations demonstrate the activity of acetate-degrading hyperthermophiles. Above 45°C, populated zones alternate with zones up to 192 meters thick where microbes were undetectable.

Non-Destructive Techniques for Quality Evaluation of Intact Fruits and Vegetables

Abstract: Consumers are now more conscious about quality and source of their foods. Attempts made to determine the quality of food materials are numerous, but most of them are destructive in nature. In recent years, nondestructive methods of quality evaluation have gained momentum and a considerable attempts have been made to develop them. This paper reviews application of these non-destructive methods: magnetic resonance imaging, x-ray computer tomography, near infrared spectroscopy and a few other important techniques for determination of different quality attributes with emphasis on fruits and vegetables, and discusses their pros and cons for practical exploitation.

Correlations of the arrival directions of ultra-high energy cosmic rays with extragalactic objects as observed by the telescope array experiment

Abstract: We search for correlations between the positions of extragalactic objects and the arrival directions of ultra-high energy cosmic rays (UHECRs) with primary energy E ≥ 40 EeV as observed by the surface detector array of the Telescope Array (TA) experiment during the first 40 months of operation. We examine several public astronomical object catalogs, including the Veron-Cetty and Veron catalog of active galactic nuclei. We count the number of TA events correlated with objects in each catalog as a function of three parameters: the maximum angular separation between a TA event and an object, the minimum energy of the events, and the maximum redshift of the objects. We determine the combination of these parameters that maximizes the correlations, and we calculate the probability of having the same levels of correlations from an isotropic distribution of UHECR arrival directions. No statistically significant correlations are found when penalties for scanning over the above parameters and for searching in several catalogs are taken into account.