MULTIPLE USES OF SMALL-SCALE VALLEY BOTTOM LAND:CASE STUDY OF THE MATENGO IN SOUTHERN TANZANIA

Many recent studies have examined wetlands as a food supply resource in sub-Saharan Africa. Although a number of studies have investigated the use of large-scale wetlands such as swamps and floodplains, little is known about the use of small-scale valley bottom lands. The Matengo, who are Bantu speakers living in mountainous southern Tanzania, have developed intensive use of ntambo, the principal unit of land tenure and use. Ntambo land use is based on an indigenous farming system called ngolo as well as coffee cultivation. At the same time, small valley bottom lands (kijungu) have also been used. In recent years, people have begun to pay greater attention to diversifying kijungu land use against the backdrop of economic liberalisation, climate change, and population pressure.Cultivating the kijungu provides the Matengo not only with food during times of scarcity but also with petty cash called `hela ya haraka' for daily use throughout the year. As their use is diversified and expanded, kijungu may be vital for sustaining the Matengo's livelihood and will become increasingly important in enforcing relationships between other subsistence activities

Whole body counter surveys of Miharu-town school children for four consecutive years after the Fukushima NPP accident

Comprehensive whole-body counter surveys of Miharu town school children have been conducted for four consecutive years, in 2011-2014. This represents the only long-term sampling-bias-free study of its type conducted after the Fukushima Dai-ichi accident. For the first time in 2014, a new device called the Babyscan, which has a low $^{134/137}$Cs MDA of $< 50$ Bq/body, was used to screen the children shorter than 130 cm. No child in this group was found to have detectable level of radiocesium. Using the MDAs, upper limits of daily intake of radiocesium were estimated for each child. For those screened with the Babyscan, the upper intake limits were found to be <1 Bq/day for $^{137}$Cs. Analysis of a questionnaire filled out by the children's parents regarding their food and water consumption shows that the majority of Miharu children regularly consume local and/or home-grown rice and vegetables. This however does not increase the body burden.Comment: 11 pages, 10 figure

Discharge properties of identified cochlear nucleus neurons and auditory nerve fibers in response to repetitive electrical stimulation of the auditory nerve

Using the in vitro isolated whole brain preparation of the guinea pig maintained at 29°C, we intracellularly recorded and stained cochlear nucleus (CN) neurons and auditory nerve (AN) fibers. Discharge properties of CN cells and AN axons were tested in response to 50-ms trains of electrical pulses delivered to the AN at rates ranging from 100 to 1000 pulses per second (pps). At low stimulation rates (200-300pps), the discharges of AN fibers and a large proportion of principal cells (bushy, octopus, stellate) in the ventral cochlear nucleus (VCN) followed with high probability each pulse in the train, resulting in synchronization of discharges within large populations of AN fibers and CN cells. In contrast, at high stimulation rates (500pps and higher), AN fibers and many VCN cells exhibited "primary-like", "onset" and some other discharge patterns resembling those produced by natural sound stimuli. Unlike cells in the VCN, principal cells (pyramidal, giant) of the dorsal CN did not follow the stimulating pulses even at low rates. Instead, they often showed "pauser" and "build-up" patterns of activity, characteristic for these cells in conditions of normal hearing. We hypothesize that, at low stimulation rates, the response behavior of AN fibers and VCN cells is different from the patterns of neuronal activity related to normal auditory processing, whereas high stimulation rates produce more physiologically meaningful discharge patterns. The observed differences in discharge properties of AN fibers and CN cells at different stimulation rates can contribute to significant advantages of high- versus low-rate electrical stimulation of the AN used for coding sounds in modern cochlear implant

Chaotic mode-competition dynamics in a multimode semiconductor laser with optical feedback and injection

Photonic computing is attracting increasing interest to accelerate information processing in machine learning applications. The mode-competition dynamics of multimode semiconductor lasers is useful for solving the multi-armed bandit problem in reinforcement learning for computing applications. In this study, we numerically evaluate the chaotic mode-competition dynamics in a multimode semiconductor laser with optical feedback and injection. We observe the chaotic mode-competition dynamics among the longitudinal modes and control them by injecting an external optical signal into one of the longitudinal modes. We define the dominant mode as the mode with the maximum intensity; the dominant-mode ratio for the injected mode increases as the optical injection strength increases. We find that the characteristics of the dominant mode ratio in terms of the optical injection strength are different among the modes owing to the different optical feedback phases. We propose a control technique for the characteristics of the dominant mode ratio by precisely tuning the initial optical frequency detuning between the optical injection signal and injected mode. We also evaluate the relationship between the region for the large dominant mode ratio and injection locking range. The region for the large dominant mode ratio does not correspond to the injection-locking range. This discrepancy results from the complex mode-competition dynamics in multimode semiconductor lasers with both optical feedback and injection. This control technique of chaotic mode-competition dynamics in multimode lasers is promising for applications in reinforcement learning and reservoir computing as photonic artificial intelligence.Comment: 17 pages, 12 figures, 1 tabl

A Comparative Study of the Amino-acids, Contained in Various Silks and Mulberry Leaves.

Article上田蠶絲專門學校學術報告 1(1): 1-47(1920)departmental bulletin pape

DEVELOPMENT AND INTRODUCTION OF A PICO-HYDRO SYSTEM IN SOUTHERN TANZANIA

The demand for electricity has rapidly risen in rural Tanzania due to the spread of mobile phones. In a rural village in southern Tanzania, we collaborated with a group of villagers to develop a pico-hydro system with a screw turbine and introduced it to a flat plateau with a low water head. The power generation system was designed to take advantage of the fluvial environment and gentle slopes to counteract the drastic changes in water level that can occur throughout Africa. The project began in 2010 with a pico-hydro system using a traditional Japanese screw turbine, resulting in successful power generation in 2012. This study clarified key considerations in developing a community-based pico-hydro system. Low cost, locally sourced materials and equipment are advantageous. A lightweight screw turbine power generation system is transportable to meet changing water levels. Easy reproduction and/or modification can meet changing needs. The proposed system could provide stable electrical power for lights and mobile phones. Additionally, the cooperative exchange promoted by the project inspired the local people to create their own environmental groups to take on activities that supported sustainable natural resource use