Imprints of domesticated pearl millet (Pennisetum glaucum (L.) R. Br.) spikelets, observed as temper in ceramics dating to the third millennium BC, provide the earliest evidence for the cultivation and domestication process of this crop in northern Mali. Additional sherds from the same region dating to the fifth and fourth millennium BC were examined and found to have pearl millet chaff with wild morphologies. In addition to studying sherds by stereomicroscopy and subjecting surface casts to scanning electron microscopy (SEM), we also deployed X-ray microcomputed tomography (microCT) on eleven sherds. This significantly augmented the total dataset of archaeological pearl millet chaff remains from which to document the use of the wild pearl millet as ceramic temper and the evolution of its morphology over time. Grain sizes were also estimated from spikelets preserved in the ceramics. Altogether, we are now able to chart the evolution of domesticated pearl millet in western Africa using three characteristics: the evolution of nonshattering stalked involucres; the appearance of multiple spikelet involucres, usually paired spikelets; and the increase in grain size. By the fourth millennium BC, average grain breadth had increased by 28%, although spikelet features otherwise resemble the wild type. In the third millennium BC, the average width of seeds is 38% greater than that of wild seeds, while other qualitative features of domestication are indicated by the presence of paired spikelets and the appearance of nondehiscent, stalked involucres. Nonshattering spikelets had probably become fixed by around 2000 BC, while increases in average grain size continued into the second millennium BC. These data now provide a robust sequence for the morphological evolution of domesticated pearl millet, the first indigenous crop domesticated in western Africa.
Summary Looking beyond the reaction to and the discourses surrounding inventions, it may appear incongruous to link religion with technological innovation, especially considering the underlying religious motivations of the inventive act. Steamship propulsion and the search for an alternative to the paddle wheel in 1840s France implicates three inventors (Frédéric Sauvage, Augustin Normand, Achille de Jouffroy d'Abbans) and three inventions (the continuous propeller, the divided propeller, the flipper apparatus); only Normand's propeller would have a vertiable future. This contest also entails three different types of religious temperaments: a Romantic religiosity, a “bourgeois” or private Catholicism; and a clerical‐legitimist militancy. The question which will be considered here is: were these inventors influenced by the strength of their religious convictions; and if so, how did this affect their scientific reasoning ? 相似文献
Cate, C., André Malraux: A Biography (Hutchison, 1995), xvi + 451pp., £25, ISBN 0 09 174856 9 Raymond, G., André Malraux: Politics and the Temptation of Myth (Avebury, 1995), 212pp., £35, ISBN 1 85972 132X 相似文献
The Netherlands has denoted large areas as stormwater retention areas. These areas function as temporary storage locations for stormwater when rivers cannot cope with the amount of water. A large area, the Onlanden — 2,500 hectares — was developed as such a storage area between 2008 and 2013. This peat area contains up to 300 medieval housing areas. These ‘peatmounds’, named after the current visible small mound, were explicitly mentioned as a preservation goal in the project. The preservation of the peatmounds during and after the project has been guaranteed by a combination of protective measures, research, and monitoring actions. At first a risk evaluation was performed, followed by a monitoring project focusing on the preservation of the organic part of the mounds. This evaluation showed that the rewetting of the mounds might improve the overall preservation. A total of fifteen monitoring stations were a-selectively distributed over the total area, covering the four main types of land use. The measured parameters at these stations focus on the desiccation/rewetting effects. The second threat, as determined in the risk evaluation, is the growth of deep penetrating plants. These roots might disturb the archaeological profile. Preventive coverage with plastic and up to a metre of soil could prevent root growth into the archaeology. An experimental coverage showed the effectiveness of this technique, but also the risks. This paper focuses on the lessons that can be learned from this six-year project, the monitoring results, and clearly shows the benefits of a combined approach in large-scale projects. 相似文献
The two authors have carried out an oral survey on a group of retired farm labourers in the French Vexin and the Pays de France regions (north of the lle de France). This paper examines the means by which individual memory registers the collective downward trend of this social group. It is remarkable for instance that respondents tend to recall memories of the “life of yore”;, opposed to life nowadays, instead of describing precise stages of their career, or the social evolution of their group and of the region. Their vision of History is fatalistic, syncretical, motionless, with frequent reference to war, exodus, moments of horror. All these elements express indirectly how a social group was crushed. Fragments of oral litterature that were collected on the same occasion refer also to the theme of social failure. 相似文献
When and how did the first human beings settle in the American continent? Numerous data, from archaeological researches as well as from palaeogenetics, anthropological and environmental studies, have led to partially contradictory interpretations in recent years, often because of the lack of a reliable chronological framework. The present study contributes to the establishment of such a framework using luminescence techniques to date a Brazilian archaeological site, the Toca da Tira Peia. It constitutes an exemplary case study: all our observations and measurements tend to prove the good integrity of the site and the anthropological nature of the artifacts and we are confident in the accuracy of the luminescence dating results. All these points underline the importance of the Toca da Tira Peia. The results bring new pieces of evidence of a human presence in the north-east of Brazil as early as 20,000 BC. The Toca da Tira Peia thus contributes to the rewriting of the history of the peopling of the American continent. 相似文献
A new microdomatid gastropod, Eopagodea sevillana gen. and sp. nov., is described from the Late Ordovician (pre-Hirnantian Ashgill) limestones of Seville, Ossa Morena Zone, Spain. Palaeozoic microdomatids lived in shallow-water environments and were restricted to warm-water regions. Occurrence of microdomatid gastropods in the pre-Hirnantian Ashgill limestones of the Cerrón del Hornillo syncline (Ossa Morena Zone, Spain) is interpreted as an example of an influx of warm-water faunal elements into the otherwise cool to cold climate of the Mediterranean region during a short-termed, pre-Hirnantian increase of palaeotemperatures. The Late Ordovician microdomatid genus Daidia Wilson, 1951, is revised and two new Late Ordovician (Ashgill) subspecies of Daidia cerithioides (Salter, 1859) are described: Daidia cerithioides sewardensis n. subsp. from the Don River area of the York Mountains, Seward Peninsula, western Alaska, and Daidia cerithioides wilsonae n. subsp. from the Little East Lake Formation of northwestern Maine. 相似文献
While use of polyethylene glycols, PEG, polymers for archaeological wood conservation has been well established, there is almost no study of such composite materials with carbon thirteen high-resolution solid-sate NMR. We demonstrate that NMR is an useful analytical tool to characterize rapidly samples of conserved wooden objects. By choosing an appropriate value of the contact time (from 3 to 5 ms) for which the PEG component gives only a small residual NMR signal in the CP-MAS experiment, it is possible to edit selectively the spectra of the wood components. It allows one to visualize the degradation extent of the archaeological wood even when the conservation processes have been already applied. Moreover, by studying the kinetics of CP-MAS experiments, the time constants, T1ρH and TCH values for PEG moiety were computed. From these data, it is shown that either in the crude commercial product or in incorporated in archaeological woods, two components are present and they are the signatures of crystalline (or ordered) and amorphous (or disordered) molecular domains. Moreover, it was shown in the archaeological woods that almost 30% of PEG was in close molecular interactions with lignins. This study is the first evidence that the PEG in conserved wood can interact at a molecular level with wood components. It also demonstrates that the PEG diffuses inside the residual cell walls of archaeological wood. This data are important for scientists in charge of process development for the conservation of wooden artifacts. 相似文献