Tamagawa University is a Japanese university in Machida, Tokyo, Japan. The university consists of 16 departments in seven faculties , as well as seven programs leading to a master’s degree and four programs leading to a doctorate degree. Part of the Tamagawa Gakuen campus, the school was founded by influential Japanese education reformer Kuniyoshi Obara. Wikipedia.
Futami F.,Tamagawa University
Quantum Information Processing | Year: 2014
Quantum Enigma Cipher is an epoch-making concept in the cryptography that may break the Shannon limit of the cryptography. Yuen-2000 (Y-00) protocol is a first generation toward the Quantum Enigma Cipher that overcomes the Shannon limit in cryptography relying on macroscopic quantum effects. Current Y-00 cipher is an encryption scheme where noise masking blocks an eavesdropper’s reading of the physical ciphertext consisting of the mathematical structure. No such masking effect is realized only by using the mathematical encryption, because mathematical ciphertexts are composed of binary signals, “0” or “1” or deterministic symbols, and they are correctly discriminated. Y-00 cipher is one of the candidates to provide high transmission performance and a provable security simultaneously in the real world. In our present, Y-00 cipher, mathematical cipher and physical phenomena are combined. It features multi-level signaling by mathematical cipher and noise masking to hide the ciphertext in the quantum noise and other channel noise. In the paper, transmission performance of Y-00 cipher is experimentally investigated. A running test for 60 days of Y-00 cipher transceiver at 2.5 Gbit/s is demonstrated. In addition, a trial of a current direct modulation scheme using 4096 signal levels for realizing a compact Y-00 transceiver is demonstrated. Furthermore, a wavelength-division multiplexing transmission of Y-00 cipher is experimentally demonstrated, and 100-Gbit/s Y-00 cipher transmission is successfully transmitted over 120 km. © 2014, Springer Science+Business Media New York.
Harano K.-I.,Tamagawa University
Apidologie | Year: 2013
The functions of juvenile hormone in the physiological and behavioral maturation in Apis mellifera males (drones) were investigated by application of a juvenile hormone analog, methoprene. No evidence was found for the stimulation of maturation of male reproductive organs by methoprene. The dry weight of the seminal vesicle and reproductive accessory gland was slightly but significantly lighter in drones treated with a high dose (100 or 500 μg/male) of methoprene than drones treated either with a low dose (1 or 10 μg/male) or solvent control only. Methoprene accelerated in-colony male movement from the center to the periphery. It also induced earlier diet transition from pollen and jelly-like materials to honey. These results suggest that juvenile hormone acts as a behavioral pacemaker rather than as a gonadotropin in drones. © 2013 INRA, DIB and Springer-Verlag France.
Van Boxtel J.J.A.,California Institute of Technology |
Tsuchiya N.,California Institute of Technology |
Tsuchiya N.,Tamagawa University |
Koch C.,California Institute of Technology |
Koch C.,Korea University
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010
The brain's ability to handle sensory information is influenced by both selective attention and consciousness. There is no consensus on the exact relationship between these two processes andwhether they are distinct. So far, no experiment has simultaneously manipulated both. We carried out a full factorial 2 x 2 study of the simultaneous influences of attention and consciousness (as assayed by visibility) on perception, correcting for possible concurrent changes in attention and consciousness. We investigated the duration of afterimages for all four combinations of high versus low attention and visible versus invisible. We show that selective attention and visual consciousness have opposite effects: paying attention to the gratingdecreases theduration of its afterimage,whereas consciously seeing the grating increases the afterimage duration. These findings provide clear evidence for distinctive influences of selective attention and consciousness on visual perception.
Sasaki K.,Tamagawa University
Journal of Insect Physiology | Year: 2016
Precursors of neuroactive substances can be obtained from dietary sources, which can affect the resulting production of such substances in the brain. In social species, an intake of the precursor in food could be controlled by social interactions. To test the effects of dietary tyrosine on the brain dopamine levels in social insect colonies, male and worker honeybees were fed tyrosine or royal jelly under experimental conditions and the brain levels of dopamine and its metabolite were then measured. The results showed that the levels of dopamine and its metabolite in the brains of 4- and 8-day-old workers and 8-day-old males were significantly higher in tyrosine-fed bees than in control bees, but the levels in 4-day-old males were not. The brain levels of dopamine and its metabolite in 4- and 8-day-old males and workers were significantly higher in royal jelly-fed bees than in control bees, except for one group of 4-day-old workers. Food exchanges with workers were observed in males during 1-3 days, but self-feedings were also during 5-7 days. These results suggest that the brain levels of dopamine in males can be controlled by an intake of tyrosine in food via exchanging food with nestmates and by self-feeding. © 2016 Elsevier Ltd.
Watanabe H.,Tamagawa University
Acta Horticulturae | Year: 2011
The idea of planned production of vegetables using a factory has been suggested for many years as a technology extending the application of greenhouse horticulture. However, it has not been a very long time since the world's first systematized vegetable factory appeared for commercial production. Development of vegetable factories in Japan was started in the second half of the 1970s, and subsequently many companies like manufacturers of electrical appliances, food producers, and electric power companies and so on began technology development work in this field. Currently, Japan is one of the most active countries in the world in technology development in this field. If the goals of vegetable production in factory are fully planned production and cultivation management, then in terms of lighting, a fully controlled system using artificial light only is superior to a sunlight/artificial light combined system. However, one issue with artificial lighting is the running cost, especially the cost of electricity for lighting and air conditioning. Estimates based on high pressure sodium lamps and fluorescent light indicate that lighting accounts for approximately 40% of the total running cost for vegetable production. Therefore, it is essential that electricity costs for lighting and air conditioning should be lowered in order to develop a practical vegetable factory that uses fully controlled artificial light. Light-emitting diodes (LEDs) are featured with a narrow light-emitting spectrum, enabling them to focus light on plants with just the required wavelength of light. In addition, it is possible to completely reduce thermal infrared radiation. This means the light source can be positioned very close to plants. Furthermore, the lack of infrared radiation is an important cost advantage in terms of managing the temperature of a closed vegetable cultivation system. This article will overview the history and technology development of the light-controlled plant cultivation system in Japan, especially comparing the performance and characteristics of lighting devices for vegetable cultivation.