The islands of the Central Ryukyus (Amami and Okinawa archipelagos), Japan, were continuously occupied by hunter-gatherers for several thousand years during the Holocene. This occupation would seem to represent a unique example of island settlement by hunter-gatherers. Homo sapiens had expanded into all continents except Antarctica by 10,000 BP, demonstrating high adaptability to various environments, but few islands had been settled by that time. Most islands appear to have been too small to support hunter-gatherer subsistence. Many islands were indeed first colonized by agriculturalists. Some islands located close to large landmasses, having a large surface area, or with reliable sea mammal populations or translocated plants and animals were successfully colonized by hunter-gatherers, but none of these features characterize the prehistoric Central Ryukyu Islands, which were successfully colonized by hunter-gatherers by at least the early–middle Holocene. Furthermore, this colonization was likely accomplished with smaller populations and foraging territories than previously documented for hunter-gatherers. Coral reef resources with nuts (and possibly yams) appear to have played a crucial role in this island colonization. The only similar case to prehistoric Okinawa comes from the Andaman Islands, where hunter-gatherers have occupied small tropical islands for thousands of years. The final part of this paper provides a brief comparison of the Andaman data in light of the results from the Central Ryukyus described here.

The energy relaxation time of hot carriers photoexcited in bulk InGaN is measured. The time‐resolved pump and probe transmission measurements with subpicosecond time resolution show that the hot‐carrier relaxation time is 0.92 ps at 15 K. The hot‐carrier relaxation time becomes significantly shorter at higher temperatures. At temperatures higher than 150 K, there are no meaningful differences between rise times. This strong temperature dependence indicates that electron‐phonon scattering dominates the carrier relaxation process. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Many fish remains were recovered from excavations at Man Bac during the 2005 and 2007 seasons. This chapter focuses on the identification of fish remains recovered in the 2004-5 season, with some general observations made on the 2007 assemblage. In addition, a discussion of the aquatic palaeoenvironment surrounding the site and the fishing activities of its inhabitants is outlined here. The analysis was carried out at the Institute of Archaeology, Hanoi in 2008. The elements considered for identification were maxillaries, premaxillaries, dentaries, angulars, quadrates, vertebrae and other identifiable elements. These specimens were identified through comparison with skeletal specimens of modern fishes. MATERIALS AND RESULTS Identifications The identification results are shown in Table 10.1. A total of 722 specimens were available for analysis. Separating them by strata; specifically Layer I, II, and III, yielded 561, 121, and 40 specimens respectively, with most of the specimens coming from Layer I, and the number decreasing in the lower layers. As with the mammalian assemblage (see Chapter 9) the Man Bac fish assemblage was collected by a combination of in situ recovery during excavation and the wet sieving of two excavation squares (squares E3 and G1). Among the material analysed, 692 specimens were identified to the level of order or lower, and 4 taxa of Chondrichthyes (Elasmobranchii) plus 10 taxa of Osteichthyes (Teleostei) were identified. In addition, there were 25 unidentified Osteichthyes specimens (Figure 10.1, No. 13-17). Acanthopagrus sp. (black seabreams) were the most numerous (54% of total MNI), followed by Lates calcarifer (barramundi), Siluriformes (catfishes), Rajiformes (rays), Lamnidae / Lamniformes (sharks), and Serranidae (groupers). This pattern is basically the same from Layer I to Layer III (Table 10.2, Figure 10.2). Brief Description of the Dominant Taxa Because a comparison with modern fish specimens was insufficiently detailed, the identification of the Elasmobranchii (Sharks and Rays) remains uncertain. Most of the shark vertebrae are from Carcharhinidae or similar types (Figure 10.1, No. 2),

The competition between the quantum‐confined Stark effect (QCSE) and the free‐carrier screening effect in AlGaN/GaN multiple quantum wells (MQWs) has been investigated by time‐resolved photoluminescence (PL) measurement. AlGaN/GaN MQWs is a promising material for the next‐generation ultraviolet light‐emitting diodes and laser devices. The large changes in the PL energy and the decay time are observed with changing carrier density. We show that the energy shift and the change in decay time are explained well by the free‐carrier screening effect that compensates for the internal electric field. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)