Facile aerial oxidation is a general feature of guanine ribo- and 2'-deoxyribonucleosides that are substituted at the 8-position by an aminoaryl group. In previous work, it had been suggested that two of the major oxidation products are a pair of diastereomers having a spiro structure. These were presumed to be related by a chiral difference at the spiro carbon atom. The pattern of the oxidative process involves a contraction of the pyrimidine ring. It was thought to be analogous to that suggested by other investigators for the oxidation of uric acid, but for which no really definitive evidence had been presented. We have been able now to isolate in a crystalline state one of the diastereomers produced by the aerial oxidation of 8-phenylaminoguanosine under alkaline conditions. Analysis by X-ray diffraction has now confirmed the type of spiro structure promulgated previously. These findings also imply that spiro compounds are likely to be produced during the aerial oxidation of any 8-arylaminoguanine nucleoside or 2'-deoxynucleoside. In addition, this work adds considerable weight to the results of Poje and Sokolic-Maravic who proposed that a spiro intermediate is produced during the aerial oxidation of uric acid (12,13). However, they found this compound to be unstable to base, in contrast to the arylaminoguanine oxidation products. In the course of the above work we showed that the 8-arylamino derivatives of guanosine can be converted by the Barton deoxygenation method to the corresponding 2'-deoxyribonucleosides. This makes available a number of the latter compounds, which are not easily prepared by other methods.

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In an accompanying paper (Journal of Anthropological Research 73(2):149-80, 2017), the authors assess current archaeological and paleobiological evidence for the early Neolithic of China. Emerging trends in archaeological data indicate that early agriculture developed variably: hunting remained important on the Loess Plateau, and aquatic-based foraging and protodomestication augmented cereal agriculture in South China. In North China and the Yangtze Basin, semisedentism and seasonal foraging persisted alongside early Neolithic culture traits such as organized villages, large storage structures, ceramic vessels, and polished stone tool assemblages. In this paper, we seek to explain incipient agriculture as a predictable, system-level cultural response of prehistoric foragers through an evolutionary assessment of archaeological evidence for the preceding Paleolithic to Neolithic transition (PNT). We synthesize a broad range of diagnostic artifacts, settlement, site structure, and biological remains to develop a working hypothesis that agriculture was differentially developed or adopted according to "initial conditions" of habitat, resource structure, and cultural organization. The PNT of China is characterized by multiple, divergent evolutionary pathways: between the eastern and western parts of North China, and between and the Yangtze Valley and the Lingnan region farther south.

The earliest evidence for agriculture in Taiwan dates to about 6000 years BP and indicates that farmer-gardeners from Southeast China migrated across the Taiwan Strait. However, little is known about the adaptive interactions between Taiwanese foragers and Neolithic Chinese farmers during the transition. This paper considers theoretical expectations from human behavioral ecology based models and macroecological patterning from Binford’s hunter-gatherer database to scope the range of responses of native populations to invasive dispersal. Niche variation theory and invasion theory predict that the foraging niche breadths will narrow for native populations and morphologically similar dispersing populations. The encounter contingent prey choice model indicates that groups under resource depression from depleted high-ranked resources will increasingly take low-ranked resources upon encounter. The ideal free distribution with Allee effects categorizes settlement into highly ranked habitats selected on the basis of encounter rates with preferred prey, with niche construction potentially contributing to an upswing in some highly ranked prey species. In coastal plain habitats preferred by farming immigrants, interactions and competition either reduced encounter rates with high ranked prey or were offset by benefits to habitat from the creation of a mosaic of succession ecozones by cultivation. Aquatic-focused foragers were eventually constrained to broaden subsistence by increasing the harvest of low ranked resources, then mobility-compatible Neolithic cultigens were added as a niche-broadening tactic. In locations less suitable for farming, fishing and hunting continued as primary foraging tactics for centuries after Neolithic arrivals. The paper concludes with a set of evidence-based archaeological expectations derived from these models.

The geometric phase is a fundamental quantity characterizing the holonomic feature of quantum systems. It is well known that the evolution operator of a quantum system undergoing a cyclic evolution can be simply written as the product of holonomic and dynamical components for the three special cases concerning the Berry phase, adiabatic non-Abelian geometric phase, and nonadiabatic Abelian geometric phase. However, for the most general case concerning the nonadiabatic non-Abelian geometric phase, how to separate the evolution operator into holonomic and dynamical components is a long-standing open problem. In this work, we solve this open problem. We show that the evolution operator of a quantum system can always be separated into the product of holonomy and dynamic operators. Based on it, we further derive a matrix representation of this separation formula for cyclic evolution, and give a necessary and sufficient condition for a general evolution being purely holonomic. Our finding is not only of theoretical interest itself, but also of vital importance for the application of quantum holonomy. It unifies the representations of all four types of evolution concerning the adiabatic/nonadiabatic Abelian/non-Abelian geometric phase, and provides a general approach to realizing purely holonomic evolution.