Diamonds and the african lithosphere

Data and inferences drawn from studies of diamond inclusions, xenocrysts, and xenoliths in the kimberlites of southern Africa are combined to characterize the structure of that portion of the Kaapvaal craton that lies within the mantle. The craton has a root composed in large part of peridotites that are strongly depleted in basaltic components. The asthenosphere boundary shelves from depths of 170 to 190 kilometers beneath the craton to approximately 140 kilometers beneath the mobile belts bordering the craton on the south and west. The root formed earlier than 3 billion years ago, and at that time ambient temperatures in it were 900 degrees to 1200 degrees C; these temperatures are near those estimated from data for xenoliths erupted in the Late Cretaceous or from present-day heat-flow measurements. Many of the diamonds in southern Africa are believed to have crystallized in this root in Archean time and were xenocrysts in the kimberlites that brought them to the surface.     

Decipherment of the earliest tablets

The first signs of writing were crudely impressed on clay tablets. These signs are found to represent and stand for clay tokens used for recording prior to writing. The recent decoding of a series of tokens makes it possible to identify the signs as units of grain metrology, land measure, animal numeration, and other economic units.     

The earliest primates

The known range of the Primates is extended down from the middle Paleocene to the early Paleocene and late Cretaceous by a new genus and two new species from Montana, Purgatorius unio and P. ceratops. These species approach condylarths and leptictid and erinaceoid insectivores in structure. Purgatorius is referred to a new subfamily, Purgatoriinae, of the Paromomyidae, but is probably not the stem primate. The fauna of Purgatory Hill indicates a late early Paleocene age.     

Sexual dimorphism: the horns of african antelopes

Comparisons of the horns of males and females across genera of African antelopes indicate that male horns are better adapted for clashing or pushing against another pair of horns during intrasexual combat. The horns of females are relatively more specialized as stabbing weapons. Horns in females are found in only half the genera and in those genera where females have horns, the genera are heavier than genera with hornless females.     

Basal anthropoids from Egypt and the antiquity of Africa's higher primate radiation

Early anthropoid evolution in Afro-Arabia is poorly documented, with only a few isolated teeth known from before approximately 35 million years ago. Here we describe craniodental remains of the primitive anthropoid Biretia from approximately 37-million-year-old rocks in Egypt. Biretia is unique among early anthropoids in exhibiting evidence for nocturnality, but derived dental features shared with younger parapithecids draw this genus, and possibly >45-million-year-old Algeripithecus, into a morphologically and behaviorally diverse parapithecoid clade of great antiquity.     

特早熟试管杏新品种群的选育

本项目首次研究了特早熟杏胚培育种 ,解决了 7项胚培技术关键 ,建立了特早熟杏胚培育种技术体系 ,首次人工育成 10个特早熟试管杏新品种 ,形成了一个特早熟试管杏品种群。以新育成的特早熟杏为试材 ,研究了果实性状遗传、雌雄蕊发育、自花和异花授粉亲和性、花期抗霜冻能力及配套栽培技术。该品种群果实发育期 5 0～ 5 7天 ,自花结实率高达 19%～ 31% ,花期抗霜冻能力强 ,早果丰产 ,色彩艳丽 ,酸甜适口 ,品质极佳 ,综合性状明显优于华北生态群老品种和欧洲生态群。现正在有计划地进行成果转化和产业化开发 ,已在全国 16个省 (市 )推广