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Pierre de Maret 《African Archaeological Review》1986,4(1):103-133
Summary Now, for the first time, it is possible to place in an exact archaeological context the polished tools which have been collected for many years on the surface in the savanna immediately to the south of the equatorial forest. In Lower Zaïre, in an area of 6000 km2, polished tools have been found systematically associated with a particular type of pottery. This pottery, which was previously known as Groupvi pottery and which we propose calling Ngovo group pottery is very distinctive.Although faunal remains associated in one case were of wild animals, someElaeïs andCanarium nuts could indicate the beginnings of agriculture. A series of dates in good agreement place these polished tools and this pottery within the last two centuries bc.At the present time, iron-working in Lower Zaïre has not been dated prior to the second century ad. This Early Iron Age is associated with the Kay Ladio group pottery which is possibly derived from the Ngovo group.
Résumé Pour la première fois, il est possible de préciser le contexte archéologique des outils polis que depuis longtemps on recueillait en surface dans les savanes immédiatement au sud de la forêt équatoriale.Au Bas-Zaïre, dans une zone de plus de 6000 km2, des outils polis ont été trouvés systématiquement en association avec une céramique d'un type particulier. Cette céramique, connue précédemment sous le nom de céramique du groupevi et que l'on propose d'appeler dorénavant groupe de Ngovo, est très caractéristique.Bien que les restes de faune qui y sont associés dans une grotte soient ceux d'animaux sauvages, des noix d'Elaeïs et deCanarium indiquent peut-être un début d'agriculture.Une série de datations remarquablement convergentes placent ces outils polis et cette céramique durant les deux derniers siècles bc.La métallurgie n'est jusqu'à présent pas datée au Bas-Zaïre avant le 2e siècle ad. Cet âge du fer ancien est associé à la céramique du groupe Kay Ladio qui dérive peut-être du groupe de Ngovo.相似文献
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Geographical variables generally show spatially structured patterns corresponding to intrinsic characteristics of the environment. The size of the sampling unit has a critical effect on our perception of phenomena and is closely related to the variance and correlation structure of the data. Geostatistical theory uses analytical relationships for change of support (change of sampling unit size), allowing prediction of the variance and autocorrelation structure that would be observed if a survey was conducted using different sampling unit sizes. To check the geostatistical predictions, we use a test case about tree density in the tropical rain forest of the Pasoh Reserve, Malaysia. This data set contains exhaustive information about individual tree locations, so it allows us to simulate and compare various sampling designs. The original data set was reorganized to compute tree densities for 5 times 5-, 10 times 10-, and 20 times 20-meter quadrat sizes. Based upon the 5 times 5-meter data set, the spatial structure is modeled using a nugget effect (white noise) plus an exponential model. The change of support relationships, using within-quadrat variances inferred from the variogram model, predict the spatial autocorrelation structure and new variances corresponding to 10 times 10-meter and 20 times 20-meter quadrats. The theoretical and empirical results agreed closely, whereas neglecting the autocorrelation structure would have led to largely underestimating the variance. As the quadrat size increases, the range of autocorrelation increases, while the variance and the proportion of noise in the data decrease. 相似文献
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The investigation of a simple behavior, child naming, can provide insights into the varying reactions of families confronted by the extraordinary war losses of the First World War. The current study analyses names given in a large cohort of French orphans born 1914–1916, constructed thanks to the linkage of civil registers with a nationwide database of soldiers who died during the War. It shows that a prenatal loss of father was associated with a strong increase in father's name transmission. The phenomenon was twice as intense in officers' offspring. Regression analysis suggests the precise timing of the father's death controlled this change in naming behavior: father's name transmission was at a maximum when the father died at the very beginning of pregnancy. 相似文献
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A simplified model useful for assessing economic losses due to moderate seismicity events in urban areas has been developed by studying the behavior of buildings before yielding their structural system, allowing for nonuniform stiffness along their height. In particular, buildings are modeled as cantilever shear beams with uniform mass and parabolic reduction of lateral stiffness. This particular stiffness distribution is relevant, as it could be expected to occur in buildings where earthquake action is a critical structural design criterion. The equation of motion governing the dynamic behavior of the proposed model is solved analytically, finding mode shapes in terms of first and second zero-order Legendre functions. The solution is verified by comparing it with results obtained from fine mesh finite element models. The effect of reducing the lateral stiffness is then studied in the first five modes of vibration. Results include modal periods, mode shapes, modal participation factors, and derivatives of mode shapes. In general, it is found that effects of reduction of lateral stiffness in mode shapes are moderate when the lateral stiffness in the free end is smaller than about seventy percent of the lateral stiffness at the fixed end, but become significant for larger reductions. Effects are particularly important for the derivative of the mode shapes, which could play a significant role in estimating interstory drift demands in buildings. Model usefulness is showcased by analyzing a test case where both acceleration and drift demands are assessed by considering uniform beams and beams with parabolic stiffness variation, finding notable improvements by considering the latter. 相似文献
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A sailing replica based on the archaeological remains and structural analysis of the 6th‐century archaic Greek sewn boat Jules‐Verne 9 was built in Marseille as part of the city's European Capital of Culture 2013 programme. Full‐scale reconstruction allowed investigation of specific aspects of the methods used to build a shell‐first, sewn‐plank, and lashed‐frame vessel, as well as learning the gestures and know‐how of the original shipbuilders. The first two seasons of sailing trials, including short journeys in the Bay of Marseille and longer, coast‐hopping expeditions, reflecting the uses of the original vessel have taken place and are reported here. 相似文献