Inter-group violence among early Holocene hunter-gatherers of West Turkana, Kenya.

The nature of inter-group relations among prehistoric hunter-gatherers remains disputed, with arguments in favour and against the existence of warfare before the development of sedentary societies. Here we report on a case of inter-group violence towards a group of hunter-gatherers from Nataruk, west of Lake Turkana, which during the late Pleistocene/early Holocene period extended about 30 km beyond its present-day shore. Ten of the twelve articulated skeletons found at Nataruk show evidence of having died violently at the edge of a lagoon, into which some of the bodies fell. The remains from Nataruk are unique, preserved by the particular conditions of the lagoon with no evidence of deliberate burial. They offer a rare glimpse into the life and death of past foraging people, and evidence that warfare was part of the repertoire of inter-group relations among prehistoric hunter-gatherers.

A microprocessor-controlled photon counter for pulsed optically detected magnetic resonance.

In pulsed optically detected magnetic resonance (ODMR) spectroscopy, a lock-in amplifier is used to monitor the signal which is phase-matched to the duty cycle of an applied sequence of pulses. However, since the desired signals reside atop a much larger amplitude-modulated signal, lock-in amplification methods are difficult to use. Commerically available photon counters are of limited use, because the pulsed ODMR method requires sequential counting over several time intervals, often with minimum time delay between the intervals. The multiaccumulator photon counter described here is capable of such sequential counting over as many as four intervals. The microprocessor which controls the counter algebraically manipulates the photon counts during each of the duty cycles. The result is an inexpensive yet versatile photon counter which is suited for pulsed ODMR and other applications in which sequential counting is necessary.