Melting of iron at the physical conditions of the Earth's core

Seismological data can yield physical properties of the Earth's core, such as its size and seismic anisotropy. A well-constrained iron phase diagram, however, is essential to determine the temperatures at core boundaries and the crystal structure of the solid inner core. To date, the iron phase diagram at high pressure has been investigated experimentally through both laser-heated diamond-anvil cell and shock-compression techniques, as well as through theoretical calculations. Despite these contributions, a consensus on the melt line or the high-pressure, high-temperature phase of iron is lacking. Here we report new and re-analysed sound velocity measurements of shock-compressed iron at Earth-core conditions. We show that melting starts at 225 +/- 3 GPa (5,100 +/- 500 K) and is complete at 260 +/- 3 GPa (6,100 +/- 500 K), both on the Hugoniot curve-the locus of shock-compressed states. This new melting pressure is lower than previously reported, and we find no evidence for a previously reported solid-solid phase transition on the Hugoniot curve near 200 GPa (ref. 16).     

Science,sensitivity and the sociozoological scale: Constituting and complicating the human-animal boundary at the 1875 Royal Commission on Vivisection and beyond

Arnold Arluke and Clinton Sanders (1996) have argued that human societies index both humans and animals as belonging to particular rungs of the social hierarchy. They term this multispecies ranking the “sociozoological scale”. This paper will investigate how claims at the 1875 Royal Commission on Vivisection about the sensitivity of particular species and breeds not only reflected assumptions about human social hierarchy but also blurred the boundaries between the human and the animal in the process. It will further be shown how these claims were informed by 18th and 19th century humanitarianism, classism, scientific racism and evolutionary theory, and how these influences combined in claims-making about the relative capacity of particular animals to sense pain and ethical duties towards them that followed from this sensitivity. Particular attention will be given to the opposing efforts of commissioners Thomas Henry Huxley and Richard Holt Hutton to demarcate human and animal sensitivity and exempt companion animals from vivisection respectively. The paper concludes by considering the sociozoological orders constituted by the 1876 Cruelty to Animals Act, particularly through its focus on calculating pain, and the legacy and limitations of this constitution.     

医用胶粘剂主体材料α-氰基丙烯酸正辛酯的合成研究

以氰乙酸正辛酯为原料,通过改进合成反应条件,合成得到了一种医用胶粘剂主体材料α-氰基丙烯酸正辛酯,产率达到了71.2%,为下一步α-氰基丙烯酸酯胶粘剂性能改进奠定了基础.     

Ancient co-speciation of simian foamy viruses and primates

Although parasite-host co-speciation is a long-held hypothesis, convincing evidence for long-term co-speciation remains elusive, largely because of small numbers of hosts and parasites studied and uncertainty over rates of evolutionary change. Co-speciation is especially rare in RNA viruses, in which cross-species transfer is the dominant mode of evolution. Simian foamy viruses (SFVs) are ubiquitous, non-pathogenic retroviruses that infect all primates. Here we test the co-speciation hypothesis in SFVs and their primate hosts by comparing the phylogenies of SFV polymerase and mitochondrial cytochrome oxidase subunit II from African and Asian monkeys and apes. The phylogenetic trees were remarkably congruent in both branching order and divergence times, strongly supporting co-speciation. Molecular clock calibrations revealed an extremely low rate of SFV evolution, 1.7 x 10(-8) substitutions per site per year, making it the slowest-evolving RNA virus documented so far. These results indicate that SFVs might have co-speciated with Old World primates for at least 30 million years, making them the oldest known vertebrate RNA viruses.     

Multi-proxy evidence for late Pleistocene-Holocene environ-mental change in arid Central Asia: An overview of the RACHAD 2001 symposium

This special issue of Chinese Science Bulletin arose from a symposium entitled 揂brupt EnvironmentalChanges in Arid Asia——History and Mechanisms?RACHAD 2001) held at Lanzhou University in October 2001. This international event was attended by over 70 scientists from Australia, China, Germany, India,Mongolia, Russia, the UK and the USA. More than fifty papers were given over a three-day period on all aspects of the mechanisms and history of environmental change in Asia抯 drylands.…