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排序方式: 共有109条查询结果,搜索用时 31 毫秒
21.
Pedro Bosch Inmaculada Alemán Carlos Moreno-Castilla Miguel Botella 《Journal of archaeological science》2011
Bones treated at low temperature do not present major modifications although, macroscopically, boiled bones may be distinguished from unboiled ones as they are smoother, lighter and more transparent. Such observations should correspond to textural modifications at a nanometric level and should depend on boiling time. In this study, contemporary human bones, boiled during various time intervals, were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and nitrogen adsorption (BET). The results were used to estimate the boiling time in four archaeological samples (Neolithic bones from Malalmuerzo cave, Spain). It is concluded, comparing Neolithic bones to contemporary ones and from the textural characterization at a nanometrical level, that two of the archaeological bones were boiled and that they were boiled for less than 6 hours. 相似文献
22.
We present a scheme to modify empirical Green's functions by attenuation considering: (1) geometrical spreading; (2) decay in high frequency; (3) regional attenuation; and (4) phase of the signal. The accelerograms computed with the proposed simulation method are compared, in time and frequency domains, with strong ground motions from subduction and intermediate-depth earthquakes recorded in Mexico. It is shown that this simple empirical Green's functions technique can synthesize both the shape and amplitude of the response spectra in the site, considering a postulated seismic source located at different distances from the original one. 相似文献
23.
Virginia García-Marín Pablo García-López Miguel Freire 《Journal of the history of the neurosciences》2013,22(2):197-210
Abstract Multiple sclerosis (MS) was first presented in a clinical setting in 1838. In this paper the presentation and treatment of a transient hemiparesis in a drummer in 1789 is discussed. This may have been an early case of MS and presents evidence against the theory that MS is an infectious disease beginning in the 19th century. 相似文献
24.
Miguel de Asúa 《Journal of the history of the neurosciences》2013,22(2):160-174
Dr. Haakon Sæthre was a leader of Norwegian neurology and psychiatry. He was resourceful, compassionate and had immense pride in his independent homeland. He described Sæthre-Chotzen syndrome (acrocephalosyndactyly type III). When Nazi Germany occupied Norway during World War II, Sæthre fearlessly and actively resisted, from revoking his medical association membership, to hiding persecuted Jews as patients in his psychiatric ward and aiding in their escape to Sweden, to managing the largest “illegal” food warehouse in Oslo with Danish humanitarian aid. As a prominent and noticeable citizen, he was arrested and executed by the Nazis in reprisal for the resistance's assassination of a hated Norwegian Nazi. His legacy lives on in Norway, where he was honored by a scholarship fund, a portrait and multiple plaques at Ullevål Hospital, and a street and memorial statue in his hometown. He was a hero and should be remembered by all who practice neurology. 相似文献
25.
Alessandra Pecci Gianluca Giorgi Laura Salvini Miguel Ángel Cau Ontiveros 《Journal of archaeological science》2013
The identification of the organic residues preserved in archaeological materials yields good insights into understanding food production, trade and consumption. Wine is one of the most important beverages produced, traded and consumed in the Mediterranean area. Consequently, it is important to identify its presence in ancient materials. Nevertheless, the identification of wine markers is still an object of discussion. We present here the results obtained from analysing different materials using gas chromatography/mass spectrometry (GC/MS), which allowed for the identification of tartaric acid and other markers of wine. The method was first tested on experimental and traditional materials that have been used until recently to store and/or produce wine and was then used for investigating archaeological materials. The experiments also involved the degradation of wine through cooking, drastic heating and burial for seven years. The results from the analysis of ceramic and plaster materials are discussed. 相似文献
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Savvas Saloustros Luca Pelà Miguel Cervera Pere Roca 《International Journal of Architectural Heritage》2018,12(3):432-447
ABSTRACTFinite element macro-modeling approaches are widely used for the analysis of large-scale masonry structures. Despite their efficiency, they still face two important challenges: the realistic representation of damage and a reasonable independency of the numerical results to the used discretization. In this work, the classical smeared crack approach is enhanced with a crack-tracking algorithm, originating from the analysis of localized cracking in quasi-brittle materials. The proposed algorithm is for the first time applied to a large-scale wall exhibiting multiple shear and flexural cracking. Discussion covers structural aspects, as the response of the structure under different assumptions regarding the floor rigidity, but also numerical issues, commonly overlooked in the simulation of large structures, such the mesh-dependency of the numerical results. 相似文献
29.
Miguel Delgado 《Archaeological and Anthropological Sciences》2018,10(4):817-832
The Sabana de Bogotá in the northern Andes is an interesting region to investigate temporal patterns of dietary variation because it counts with a vast archeological and osteological record for the last 10,000 years. In this paper, stable isotope data of human archeological bone collagen and apatite were used to study the evolution of diet and major subsistence transformations taking place during the Holocene (~9000–600 cal BP). Paleoenvironmental reconstructions and the isotopic ecology of the Sabana de Bogotá were used as an interpretative baseline. Stable isotope measurements (δ13Ccol, δ13Cap, δ15N, and Δ13Ccol-ap) representing hunter-gatherers, horticulturalists, and agriculturalists (N = 134 individuals) were analyzed by using bivariate, regressional, and discriminant statistical techniques. Results show that early Holocene hunter-gatherers (9000–7000 cal BP) consumed mostly C3 vegetal resources locally available. In contrast, animal protein was less important. Middle Holocene hunter-gatherers (6000–4500 cal BP) continued with the food foraging pattern observed in the earlier counterparts and presented a slight increase in C3 animal protein intake. During the initial late Holocene ca. 4000 cal BP, important shifts in subsistence strategies occurred when populations presented a trend toward mixed C3/C4 diets, and by ca. 3500 cal BP, there is a clear signal of C4 crops (i.e., maize) consumption concomitant with the introduction of ceramic technology. During the final late Holocene (last 2000 cal years BP), intensive agriculture was adopted and humans presented relatively diverse diets integrated by C4 and C3 crops, C3-C4 feeding animals, and freshwater resources. Such dietary change coincides with an increase in sociopolitical complexity, population size, and a general decline in health. 相似文献
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