A previously undocumented group of wild chimpanzees (Pan troglodytes verus) was recently discovered along the Pampana River in the Tonkolili District of Sierra Leone. Based on interviews from local residents (N = 6), we estimate the group size to be approximately 30 individuals. Though this population does not show up in the most recent census of chimpanzees in Sierra Leone, it concurs with findings that indicate most of the chimpanzees in Sierra Leone live scattered throughout the country alongside villages, rather than in protected areas. During a three-week observation in the area, two chimpanzees were hunted and killed. The reason for these deaths, along with other reported instances of hunting in the area, are primarily due to crop-raiding and competition for resources between chimpanzees and humans. We conclude that this is a heavily imperiled population. Based on the ecology of the area and composition of local villages, we propose a number of conservation strategies that will promote a symbiotic relationship between the chimpanzees and human populations residing in the area.

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This work tested the feasibility of a silicon-on-insulator microdosimeter, which mimics the size and shape of specific cells within the human body, to determine dose equivalent from neutron irradiation. The microdosimeters were analyzed in terms of their basic diode characteristics, i.e., leakage current as a function of bias voltage. Lineal energy spectra were acquired using two different converter layers placed atop the microdosimeter: a tissue-substitute converter made from high-density polyethylene, and a boron converter consisting of epoxy coated with boron powder. The spectra were then converted into absorbed dose and dose equivalent. Experimental results were compared to Monte Carlo simulations of the neutron irradiations, revealing good agreement. Uncertainty in the dose equivalent determinations was 7.5% when using the cell-shaped microdosimeter with the tissue-substitute converter and 13.1% when using the boron converter. This work confirmed that the SOI approach to cell-mimicking microdosimetry is feasible.