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1.
The assessment of the degree of similarity or difference between Neanderthals and modern humans in their patterns of dental development remains a controversial matter. Here we report results from the microtomographic-based (SR-μCT) high-resolution structural investigation of the maxilla and mandible of the Neanderthal child from Roc de Marsal, Dordogne, France (likely from OIS 5a). Following their virtual extraction and 3D rendering, we assessed the maturational stage of each of the 41 dental elements (20 deciduous and 21 permanent) forming its mixed dentition. By using a Bayesian approach, we calculated the probability that its deciduous and permanent mandibular sequences are found within the extant human variation as illustrated by a tomographic CT-based sub-sample of 32 children (deciduous dentition) and a panoramic radiographic- and CT-based whole sample of 343 living children (permanent dentition). Results show that neither the deciduous nor the permanent mandibular sequences displayed by Roc de Marsal are precisely found within our modern comparative files. In both sequences, the most influential factor is represented by a slight discrepancy in the Neanderthal child between the stage of mineralization of the first molar, which is proportionally advanced, and the maturational level reached by its incisors, which are proportionally delayed. Following a quantitative volumetric analysis of the deciduous teeth, we suggest that this characteristic may be related to differences between Neanderthals and modern humans in absolute dental size and relative size proportions between front and cheek teeth, as well as to structural differences in dental tissue proportions.  相似文献   

2.
The spatial structure of archeological sites can help reconstruct the settlement dynamics of hunter‐gatherers by providing information on the number and length of occupations. This study seeks to access this information through a comparison of seven sites. These sites are open‐air and were all excavated over large spatial areas, up to 2,000 m2, and are therefore ideal for spatial analysis, which was done using two complementary methods, lithic refitting and density zones. Both methods were assessed statistically using confidence intervals. The statistically significant results from each site were then compiled to evaluate trends that occur across the seven sites. These results were used to assess the “spatial consistency” of each assemblage and, through that, the number and duration of occupations. This study demonstrates that spatial analysis can be a powerful tool in research on occupation dynamics and can help disentangle the many occupations that often make up an archeological assemblage.  相似文献   

3.
Neandertals were effective hunters of large ungulates throughout their geographic and temporal ranges. Equipped with this knowledge, researchers in paleoanthropology continue to seek insight on the relationships between hunting and subsistence strategies with other components of the Neandertals’ niche, such as mobility, site use, and lithic technology. The Quina Mousterian deposits from the rockshelter site of Chez Pinaud Jonzac (Charente-Maritime, France; hereafter Jonzac) offer an excellent opportunity to pursue these issues. This paper focuses on the extensive and well-preserved skeletal remains of reindeer (Rangifer tarandus) recovered from recent excavations of the site, representing at least 18 individuals that were hunted by Neandertals during the fall through winter. Our zooarchaeological results indicate that all ages of reindeer were hunted but adult individuals predominate. No bias is evident in the comparable frequencies of males and females. These prey were butchered on-site, with abundant evidence of meat filleting and marrow exploitation. In the excavated sample, the absence of hearths and the almost complete lack of burned bones or stones suggest that Neandertals were not using fire to assist with processing the reindeer carcasses. The zooarchaeological results presented here indicate that reindeer were hunted during a restricted window of time when they were seasonally abundant in the local area near Jonzac. Taken together with the lithic industry based on bifacial elements, the evidence is consistent with a pattern of site use by highly mobile hunter-gatherers making frequent, short-term visits. Ongoing research at Jonzac and other Quina Mousterian localities will contribute to a better understanding of Neandertal behavior during cold climate phases.  相似文献   

4.
The morphological and anatomical responses to different depths of burial were examined in Rumex alpinus (Polygonaceae), a perennial plant with monopodial, horizontally growing rhizome. Its segments, which consist of 12–20 internodes, 1 to 2 mm in length each, are products of single growing seasons. The rhizomes regenerated from 5, 10 and 20 cm, but failed to emerge from 30 cm. Number of internodes produced during a growing season was not affected by burial but the length of internodes increased up to about 30-fold. The rhizomes growing up to the surface were subsidized by older rhizome segments. In the case of deeply buried rhizomes the carbohydrate reserves of the last-year-segment were nearly completely depleted. Evolutionary significance of the regeneration capacity is discussed.  相似文献   

5.
Two previous reconstructions of the Moroto hominoid palate and face made during the late 1960s suffer from several errors, in particular the angle at which the facial skeleton was hafted onto the palate, and the orientation of the canines, among others. A new reconstruction is based on the discovery that there is a good contact about 1cm logn between the palatal and facial pieces, which reveals that the snout was low and elongated as inAfropithecus turkanensis. Addition of a fragment of the right orbit reveals that the interorbital region was wide as inA. turkanensis. The remaining differences between the skulls from Moroto and Kalodirr are due to five factors:−1) pathology of the Moroto right premaxilla following ante-mortem loss of the right I1, which led to abnormal enlargement of the right half of the nasal cavity, 2) the incisive foramina of the Moroto palate are damaged, making them appear considerably larger than they were in life, 3) damage to the upper portions of the nasal aperture making it look higher than it would in life, 4) plastic deformation and crushing of the Kalodirr specimen has greatly reduced the width of the palate and has led to the cheek tooth rows converging to the rear, and 5) the slightly larger and ontogenetically older status of the Moroto individual. Resemblances between the Moroto and Kalodirr specimens far outweight the purported or real differences and it is concluded thatMorotopithecus bishopi is a junior subjective synonym ofAfropithecus turkanensis. The sites of Moroto and Kalodirr are unlikely to differ greatly in age (certainly not as much as 4 Ma).  相似文献   

6.
《Journal of bryology》2013,35(1):48-54
Abstract

The endemic Tasmanian hepatic Vandiemenia ratkowskiana Hewson, originally referred to the family Vandiemeniaceae (Marchantiophyta), is restudied taxonomically. The rhizoids, female plants, calyptrae and sporophytes are described for the first time. These features are closest to those of Metzgeria (Metzgeriaceae) and support the placement of Vandiemenia within the Metzgeriaceae.  相似文献   

7.
8.
Diseases of the human brain are almost universally attributed to malfunction or loss of nerve cells. However, a considerable amount of work has, during the last decade, expanded our view on the role of astrocytes in CNS (central nervous system), and this analysis suggests that astrocytes contribute to both initiation and propagation of many (if not all) neurological diseases. Astrocytes provide metabolic and trophic support to neurons and oligodendrocytes. Here, we shall endeavour a broad overviewing of the progress in the field and forward the idea that loss of homoeostatic astroglial function leads to an acute loss of neurons in the setting of acute insults such as ischaemia, whereas more subtle dysfunction of astrocytes over periods of months to years contributes to epilepsy and to progressive loss of neurons in neurodegenerative diseases. The majority of therapeutic drugs currently in clinical use target neuronal receptors, channels or transporters. Future therapeutic efforts may benefit by a stronger focus on the supportive homoeostatic functions of astrocytes.  相似文献   

9.
10.
SCF is a ubiquitin ligase and is composed of Skp1, Cul1, F-box protein, and Roc1. The catalytic site of the SCF is the Cul1/Roc1 complex and RING-finger protein Roc1. It was shown earlier that when Cul1 was co-expressed with Roc1 in Sf-9 cells in a baculovirus protein expression system, Cul1 was highly neddylated in the cell, suggesting that Roc1 may function as a Nedd8-E3 ligase. However, there is no direct evidence that Roc1 is a Nedd8-E3 in an in vitro enzyme system. Here we have shown that Roc1 binds to Ubc12, E2 for Nedd8, but not to Ubc9, E2 for SUMO-1 and Roc1 RING-finger mutant, H77A, did not bind to Ubc12. In in vitro neddylation system using purified Cul1/Roc1 complex expressed in bacteria, Roc1 promotes neddylation of Cul1. These results demonstrate that Roc1 functions as a Nedd8-E3 ligase toward Cul1. Furthermore, Roc1 and Cul1 were ubiquitinylated in a manner dependent on the neddylation of Cul1 in vitro. In addition, Cul1 was degraded through the ubiquitin-proteasome pathway, and a non-neddylated mutant Cul1, K720R, was more stable than wild-type in intact cells. Thus, neddylation of Cul1 might regulate SCF function negatively via degradation of Cul1/Roc1 complex.  相似文献   

11.
12.
This paper examines shape and size variability in Mousterian of Acheulian Tradition (MTA) handaxes and compares the observed patterns to those in the Lower Paleolithic Acheulian, both to better understand variability in MTA handaxes and to test whether or not this variability, particularly as it relates to resharpening and reduction, is structured similarly to that in the Acheulian. The Acheulian data set is based on previously published data with the addition here of a study of the handaxes from the site of Boxgrove, England. The MTA data set is based on four classic sites from southwest France with large handaxe collections. Both standard caliper-based morphometrics and Elliptical Fourier Analysis applied to coordinate data taken from digitized images of handaxes are used to assess shape. The result is that, contrary to expectations based on assumptions of evolving technological skill, handaxes in the MTA are as or more variable in shape than Acheulian ones. This variation is allometric in Acheulian handaxes, and is linked to resharpening from the tip down to the base, but is not related to size in the MTA samples. These results suggest that the goals and constraints of handaxe manufacture, but particularly handaxe reduction as a result of reworking during use, were quite different in the MTA and Acheulian, implying that conclusions about hominin cognition drawn from patterns in shape variability in handaxes must be understood in the context of artifact life histories.  相似文献   

13.
Childhood overweight and obesity is a major public health challenge for policymakers in many countries. As the most common supervisors of children’s activities, parents have a potentially important role to play in obesity prevention. However, a precondition for parents to improve their children’s diets, encourage them to be more physically active, or take them to see a doctor about their weight is for the parent to first recognize that their child is overweight or obese. This paper examines the extent of parental misclassification of child weight status, and its correlates, focusing on the role of parental education and the parent’s own obesity status. We find evidence that, among non-obese parents, those who are better-educated report their child’s weight status more accurately, but among obese parents, the better-educated are 45.18% more likely than parents with lower secondary education to give a false negative report of their child’s overweight/obesity; this may reflect social desirability bias.  相似文献   

14.
本文是康纳德教授在中国科学院古脊椎动物与古人类研究所所做系列讲座的内容概要,包括对旧石器时代考古发掘方法的介绍,及其团队通过对四处重要遗址(群)长期发掘所研究的人类演化重要学术问题的成果:1) Schöninge遗址及相关问题;2)南非Sibudu遗址和其他石器时代中期遗址及早期现代人行为;3)Tönchesberg, Wallertheim等遗址的发掘与尼安德特人石器技术的多样性;4) Swabian Jura洞穴发掘和艺术、音乐的起源。通过此次系列讲座,他与中国学者分享国外旧石器时代考古的发掘方法、旧大陆西部不同区域遗址的考古学材料及相关研究成果,并希望未来能够加强交流与合作研究,共同推进旧石器时代考古的发展。  相似文献   

15.
The closely related species Rhipicephalus appendiculatus and R. zambeziensis co-occur in a wide area in Zambia. In this area, specimens of both species have been collected on the same individual host at the same time. In addition, specimens that are morphologically intermediate between R. appendiculatus and R. zambeziensis have been found in this area. These observations cast some doubt on the species status of R. appendiculatus and R. zambeziensis. Because the two taxa have varied influences on the epidemiology of East Coast fever (ECF), a cattle disease for which they act as vectors, it is essential that their taxonomic status is clarified and their identification is accurate. Therefore a phylogenetic analysis of nucleotide sequences of the ITS2 and a fragment of the mitochondrial 12S rDNA was performed to reassess the specific status of both taxa. This revealed two well supported clades coinciding with R. appendiculatus and R. zambeziensis as two separate species. In order to facilitate species identification a PCR-RFLP diagnostic assay was developed based on BauI digestion of the ITS2 gene. This assay produced clear diagnostic banding patterns for the two species and is applicable over a wide range of both species’ distribution. Nucleotide sequence data reported in this paper are available in the GenBank™ under the accession numbers DQ849203–DQ849274.  相似文献   

16.
A monotypic new genus, Coleicarpus, is proposed for Castericystis? sprinklei Ubaghs & Robison 1988, the only solute known to be attached when adult. Coleicarpus sprinklei was fixed by the tip of its stele or tail to trilobite exoskeletal fragments which themselves adhered to the sea bed. The tail of C. sprinklei is uniformly circular in cross-section and made of small non-imbricating plates which form imprecise transverse rings and longitudinal rows. The tail of C. sprinklei is not divided into discrete regions as are the tails of other solutes. C. sprinklei is probably the most primitive known solute because of its attachment and lack of tail regions. These features of its tail are consistent with the theory of the descent of solutes from a Cephalodiscus-like ancestor and also the phylogenetic placement of C. sprinklei in the stem group of the Dexiothetica, the monophyletic group which comprises the echinoderms and chordates exclusively.  相似文献   

17.
Ethological studies have shown that besides human groups, large-medium carnivores have bone-collecting habits. The research developed since the last half of the twentieth century has attempted to characterise the carnivore’s accumulations and to identify them in the archaeo-paleontological record. At present, we have diagnostic criteria that define the accumulations produced by hyenids (mainly, Crocuta crocuta), thereby allowing us to differentiate them from the other accumulating agents. The faunal assemblage recovered at the Early Pleistocene TD6.3 layer of the Gran Dolina site is characterised by the presence of typical elements described in hyena dens: presence of small carnivores remains, high bone breakage, low epiphysis survival and a high frequency (>30%) of specimens with carnivore induced modifications, including large amounts of digested bones. However, attritional mortality profiles, hyena’s cubs remains, mid-shaft bone cylinders or differential anatomical composition among different weight-sizes, have not been observed or are ambiguous. In addition, anthropic evidences are scarce and concentrated in the uppermost section of the layer. TD6.3 is the result of an accumulation produced by hyenas using the cave as a den, in alternation with sporadic occupations by hominin groups. TD6.3 shows that hyena fossil accumulations may present great anatomical and taxonomic variability.  相似文献   

18.
The oldest record of Cyamodus is a skull of Cyamodus tarnowitzensis (Gürich 1884, Zt dt Geol Ges. 36:125–144) from Pelsonian shallow marine deposits. During the middle Illyrian, placodonts disappeared from the Germanic Basin. With renewed upper Illyrian transgression, Cyamodus rostratus (Münster 1839, Über einige ausgezeichnete fossile Fischzähne aus dem Muschelkalk bei Bayreuth. Birner, Bayreuth, p. 14) appeared which was found in terebratulid shell-rich shallow marine deposits. Abundant remains of Cyamodus muensteri (Agassiz 1839), traditionally referred to as Cyamodus hildegardis and here synonymised with C. muensteri, have been reported from the upper Illyrian/middle Fassanian. Skeletal remains of this species are from the Grenzbitumenzone of the Monte San Giorgio lagoons. The youngest species, Cyamodus kuhnschnyderi (Nosotti and Pinna 1993 Nosotti, S and Pinna, G. 1993. Cyamodus kuhnschnyderi n. sp. novelle espèce de Cyamodontidae (Reptilia, Placodontia) du Muschelkalk supérieur allemande. Compt Rend Acad Sci Paris, 317: 847850.  [Google Scholar], Compt Rend Acad Sci Paris. 317:847–850), has been found in the upper Fassanian/lower Longobardian of the southern Germanic Basin or Burgundian Gate when marine facies in the Germanic Basin had nearly disappeared. These successive species provide evidence of monophylogenetic development with a trend towards anterior upper and lower jaw teeth reduction, along with a shortening of the rostrum, over an interval of five million years (243–238 Ma). This evolutionary trend most probably reflects adaptation to specialised feeding on seaplants. The Cyamodus osteoderm carapace was not fused to the vertebral column, and appears to have been primarily a body enhancement that produced neutral or negative buoyancy to facilitate long-period diving.  相似文献   

19.
20.
Bosherston Lakes are a series of interconnected, mesotrophic to hypereutrophic, artificially-created coastal marl lakes in Dyfed, South West Wales. Progressive eutrophication of the lake system has been produced by a high external phosphorus loading which includes phosphorus-rich effluent from a sewage treatment works (STW) in the catchment of the Lakes.Cores were taken from four sites of varying eutrophic status within the Lakes. In the surface sediment layer, organic C, N and P concentrations generally correlate directly with trophic status and reflect distance from the source of P input. At one site, sediment stratigraphy records a clear transition at 20–15 cm depth, marked by a sharp upward increase in porosity, organic C, N, and P, and iron-associated-P; decreases in organic matter C/N, C/P and N/P ratios; a sharp decrease in carbonate, and a change in the subfossil diatom assemblage. Lead-210 dating indicates that this change occurred in the period 1919 to 1938.The diatom stratigraphy and sediment geochemistry suggest that this transition reflects an increase in trophic status at this site, probably as a result of the influx of nutrient-rich water. This took place when the management of the Stackpole estate surrounding the lake system, fell into decline during the period 1919–1938.  相似文献   

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