博弈论视角下的卢沟桥事变

本文主要运用博弈论模型对卢沟桥事变从一个"地方性"事件演变为中日两国之间的全面战争这一过程进行分析.本文认为,卢沟桥事变发生伊始,中日两国都不同程度地想避免卷入全面战争,但是由于双方在卢沟桥事变后所采取的对策使得他们陷入了"谁是懦夫"的困境中,最终导致了全面战争的爆发.     

Mitochondrial DNA from 3000-year old chickens at the Teouma site,Vanuatu

Chickens were part of the Lapita cultural complex, transported into and through the Pacific by prehistoric colonists; as such they can be used as a proxy for tracking prehistoric migration and interaction. The Lapita site of Teouma in Vanuatu is well known for the recovery of complete dentate stamped pots and a cemetery containing the largest collection of Lapita period skeletons ever found. Chicken bones recovered from these excavations provide the first ancient DNA sequences from any commensal organism directly associated with a Lapita context. The ancient mtDNA sequences obtained from two Teouma chicken bones are compared with previously published archaeologically derived ancient DNA sequences to extend our understanding of the spread of chickens in Pacific prehistory. The results also show that the haplogroup E signature was present in very early populations of chickens transported into Remote Oceania. This study also adds to the suite of available data relating to isotopic signatures for commensal animals during the early settlement of Vanuatu and may reveal a different diet for Teouma chickens than those from other early prehistoric assemblages in the Pacific.     

Examining dispersal mechanisms for the translocation of chicken (Gallus gallus) from Polynesia to South America

DNA sequencing and radiocarbon dates from the archaeological site of El Arenal-1 (Arauco Peninsula, south central Chile) suggest that Polynesians may have introduced chicken (Gallus gallus) to South America prehistorically (A.D. 1300–1420). The Chilean specimen identified has the exact same amplified mtDNA pattern as samples recovered from archaeological sites in Samoa and Tonga, but is only one base different from prehistoric chicken samples from Tonga (n = 1), Niue (n = 1), Easter Island (n = 1 of 6), and Hawai'i (n = 1). To examine the possible dispersal mechanisms of chicken between Polynesian islands and the Americas, we conducted computer simulations of seafaring from these six island groups and the Tuamotus, as well as return voyages. Simulation results from sailed vessels suggest that in certain months, landfall on the Pacific Coast of South America from Samoa and Tonga was fairly successful at around 40% (particularly in March for the former and January/February for the latter). For Niue, sailed vessels were 21% successful in January with only 2% success in December. Sailed vessels from the Tuamotus (a proxy for closer island groups to the west with evidence for chicken such as the Cook Islands) were successful in January and December, with 15% and 23% of the vessels making landfall in South America. Vessels sailing from all simulations heading east from Easter Island resulted in landfall. Hawai'i had only a 1% success rate if sailing in January, but high numbers of vessels reached southern Mexico and Central America in August and September. Most landfalls occurred much farther north than Chile, in Ecuador and Peru. Unsuccessful voyages from all of the islands other than Easter Island and Hawai'i often made landfall on islands to the east. Return voyages from Chile were not possible or extremely rare during most times of the year. Overall, seafaring simulations suggest that Polynesians may not have initially landed in close proximity to El Arenal-1—contemporaneous or even earlier archaeological evidence of translocated chicken remains may indeed be found further north. In addition, if Polynesians found it difficult or impossible to return to their homeland, the possibility exists that co-mingling between Polynesians and South American groups resulted in offspring that carried an admixture of genetic traits.