African pastoralism: genetic imprints of origins and migrations     

Hanotte O  Bradley DG  Ochieng JW  Verjee Y  Hill EW  Rege JE 《Science (New York, N.Y.)》2002,296(5566):336-339

The genetic history of African cattle pastoralism is controversial and poorly understood. We reveal the genetic signatures of its origins, secondary movements, and differentiation through the study of 15 microsatellite loci in 50 indigenous cattle breeds spanning the present cattle distribution in Africa. The earliest cattle originated within the African continent, but Near East and European genetic influences are also identified. The initial expansion of African Bos taurus was likely from a single region of origin. It reached the southern part of the continent by following an eastern route rather than a western one. The B. indicus genetic influence shows a major entry point through the Horn and the East Coast of Africa and two modes of introgression into the continent.  相似文献   

Iron isotope constraints on the Archean and Paleoproterozoic ocean redox state   总被引：5，自引：0，他引：5  

Rouxel OJ  Bekker A  Edwards KJ 《Science (New York, N.Y.)》2005,307(5712):1088-1091

The response of the ocean redox state to the rise of atmospheric oxygen about 2.3 billion years ago (Ga) is a matter of controversy. Here we provide iron isotope evidence that the change in the ocean iron cycle occurred at the same time as the change in the atmospheric redox state. Variable and negative iron isotope values in pyrites older than about 2.3 Ga suggest that an iron-rich global ocean was strongly affected by the deposition of iron oxides. Between 2.3 and 1.8 Ga, positive iron isotope values of pyrite likely reflect an increase in the precipitation of iron sulfides relative to iron oxides in a redox stratified ocean.  相似文献   

Suction Feeding in Triassic Protorosaur?     

Peters D  Demes B  Krause DW  Labarbera M  Rieppel O 《Science (New York, N.Y.)》2005,308(5725):1112-3; author reply 1112-3

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The use of hand-held chlorophyll meters as a tool to assess the nitrogen status and to guide nitrogen fertilization of potato crop     

G. Gianquinto  J. P. Goffart  M. Olivier  G. Guarda  M. Colauzzi  L. Dalla Costa  G. Delle Vedove  J. Vos  D. K. L. Mackerron 《Potato Research》2004,47(1-2):35-80

Summary Fifteen experiments were carried out in different sites of Italy, Belgium, Scotland and The Netherlands from 1995 to 1999 to study the possible use of chlorophyll meter to assess the nitrogen status and to guide nitrogen fertilization of the potato crop. The results are gathered here and reviewed together with available information in literature. The paper deals with measuring principles of chlorophyll meter; relation between chlorophyll meter readings and analytical measurements of chlorophyll, analytical measurements of nitrogen, crop nitrogen content, tuber yield, and physiological processes in leaves; variations in chlorophyll meter readings related to nitrogen supply, potato cultivar, crop management, and sampling methods; use of chlorophyll meter readings for decision making in the management of supplemental nitrogen fertilization (assessment of chlorophyll meter critical threshold, plant response to addition of supplementary N).  相似文献   

Chemical synthesis of hydroxycinnamic acid glucosides and evaluation of their ability to stabilize natural colors via anthocyanin copigmentation     

Galland S  Mora N  Abert-Vian M  Rakotomanomana N  Dangles O 《Journal of agricultural and food chemistry》2007,55(18):7573-7579

This work describes the chemical synthesis of O-aryl-beta-D-glucosides and 1-O-beta-D-glucosyl esters of hydroxycinnamic acids. In particular, O-aryl-beta-D-glucosides were efficiently prepared via a simple diastereoselective glycosylation procedure using phase transfer conditions. Despite the lability of its ester linkage, 1-O-beta-D-caffeoylglucose could also be obtained using a Lewis acid catalyzed glycosylation step and a set of protective groups that can be removed under neutral conditions. Hydroxycinnamic acid O-aryl-beta-D-glucosides were then quantitatively investigated for their affinity for the naturally occurring anthocyanin malvin (pigment). Formation of the pi-stacking molecular complexes (copigmentation) was characterized in terms of binding constants and enthalpy and entropy changes. The glucosyl moiety did not significantly alter these thermodynamic parameters, in line with a binding process solely involving the polyphenolic nuclei.  相似文献   

Comparison of the Susceptibility of Quercus petraea, Q. robur and Q. rubra to Collybia fusipes     

Benoit Marçais  Olivier Caël 《European journal of plant pathology / European Foundation for Plant Pathology》2000,106(3):227-232

Collybia fusipes is the cause of a root rot of Quercus petraea (sessile oak), Q. robur (pedunculate oak) and Q. rubra (red oak). This parasite is often reported to cause problems in stands of red oaks and field evidence suggests that this North American oak species is more susceptible than the two European oak species. Young saplings of the three oak species and of chestnut, Castanea sativa, in the glasshouse, and also mature sessile and red oaks growing in the same stand were inoculated with C. fusipes to compare their susceptibility. Red oak, both as young seedlings and mature trees, was more susceptible to C. fusipes than sessile oak. Chestnut seedlings were as susceptible as sessile oak. Susceptibility of pedunculate oak seedlings was intermediate between red oak and sessile oak. In one experiment this species was significantly less susceptible than red oak, and in the other it was as susceptible.  相似文献   

Comparison of cone-beam and fan-beam computed tomography and low-field magnetic resonance imaging for detection of proximal phalanx dorsoproximal osteochondral defects     

Szu-Ting Lin  Nicholas M. Bolas  David R. Sargan  Olivier Restif  Vanessa G. Peter  Rachel Pokora  Hayley Patrick  Alastair K. Foote  Rachel C. Murray 《Equine veterinary journal》2024,56(3):484-493

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Community livelihood and patterns of natural resources uses in the shrimp‐farm impacted Mekong Delta     

Olivier Marc Joffre  Klaus Schmitt 《Aquaculture Research》2010,41(12):1855-1866

This case study looks at changing livelihood strategies of the coastal population in Soc Trang Province in the Mekong Delta, Vietnam, and their impacts on natural resources. It provides an opportunity not only to document the impact of shrimp farming on coastal livelihood but also to better understand the link between brackish water aquaculture development and natural resource use. The approach includes a socio‐economic survey in six villages of the province focusing on risk strategies and livelihood diversification. Shrimp farming was found to be less risky and more profitable for households and private companies with a higher investment capacity than for poorer households. Households facing a high risk in shrimp farming diversified their aquaculture production, with other high‐value species like mud crab and elongated goby as a coping mechanism. The use of natural resources' collection is shifting from home consumption towards market‐oriented sales of juvenile mud crabs, clams or fish (elongated goby) to supply seed for brackish water aquaculture developments.  相似文献   

Book review: Limnology in developing countries,Vol. 1, edited by B. Gopal and R.G. Wetzel,International Scientific Publications Publishers,New Delhi,India, 1995, vii + 230 pp. Free for SIL members. ISBN 81 86047 14 X.     

Olivier A. E. Sparagano 《水产资源保护:海洋与淡水生态系统》1997,7(2):181-181

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Double dose efficiency of the yellow rust resistance gene Yr17 in bread wheat lines     

Olivier Coriton  Joseph Jahier  Marc Leconte  Virginie Huteau  Gwenn Trotoux  Françoise Dedryver  Claude de-Vallavieille-Pope 《Plant Breeding》2020,139(2):263-271

Yellow rust, caused by Puccinia striiformis f. sp. tritici, is one of the most severe wheat disease worldwide. Crop losses have ranged from 10% to 70% and up to 100% in extreme conditions. Eighty-two resistance genes, designated Yr, have been identified. Among them, Yr17 derived from Aegilops ventricosa and located on chromosome 2A has been widely used in wheat breeding. However, it had been overcome already. Through recombination of the Ae. ventricosa Yr17-carrying 6N^v chromosome with 2D of wheat, we introduced Yr17 onto chromosome 2D. Then, lines carrying Yr17 on both 2A and 2D were generated. Seedlings of the latter, as well as those carrying a single dose of Yr17 either on 2A or on 2D, were inoculated with virulent or avirulent strains on wheat seedlings. The different genotypes were fully susceptible for the two pathotypes that are virulent on Yr17. In the case of avirulent pathotypes, the Yr17 double dose lines were fully resistant, while those with the Yr17 gene only on either 2A or 2D had intermediate resistance reactions towards one or the other or both pathotypes.  相似文献