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1.
In the present note an outline of the project and of the cooperation established with the Museum of the Hombre Dominicano is outlined.  相似文献   

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Motility is a common property of animal cells. Cell motility is required for embryogenesis [1], tissue morphogenesis [2] and the immune response [3] but is also involved in disease processes, such as metastasis of cancer cells [4]. Analysis of cell migration in native tissue in vivo has yet to be fully explored, but motility can be relatively easily studied in vitro in isolated cells. Recent evidence suggests that cells plated in vitro on thin lines of adhesive proteins printed onto culture dishes can recapitulate many features of in vivo migration on collagen fibers [5,6]. However, even with controlled in vitro measurements, the characteristics of motility are diverse and are dependent on the cell type, origin and external cues. One objective of the first World Cell Race was to perform a large-scale comparison of motility across many different adherent cell types under standardized conditions. To achieve a diverse selection, we enlisted the help of many international laboratories, who submitted cells for analysis. The large-scale analysis, made feasible by this competition-oriented collaboration, demonstrated that higher cell speed correlates with the persistence of movement in the same direction irrespective of cell origin.  相似文献   

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Microsatellite markers were developed for epidemiological studies on Contarinia nasturtii (Diptera, Cecidomyiidae), a native European pest that was introduced to the New World in 1996. Nine loci were found to be polymorphic and suitable for the analysis of 56 male individuals that were collected using pheromone traps. These markers all conform to Hardy–Weinberg expectations in at least one of the two tested populations, and carry an average number of 11 alleles among populations and observed levels of heterozygosity ranging from 0.32 to 0.86. Primers for all markers also successfully amplified fragments from Contarinia pisi and Contarinia tritici.  相似文献   

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Two new species of the Eocene avian taxonPlesiocathartes (Aves: ?Leptosomidae) are described. They are similar in size and overall appearance to other members of the genus, as well as to the extant Madagascan cuckoo-rollerLeptosomus discolor. So far, putative fossil Leptosomidae have been found only in the Eocene European de-posits of Messel, Geiseltal, Quercy, and London Clay. Both new species are from the Lower Eocene Green River Formation (USA) and thus the first New World representatives of this taxon.  相似文献   

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The Makapansgat Limeworks is a significant Pliocene site both for its sample of 35 hominin fossils as well as its wealth of fossil fauna. The lithological and paleontological successions reveal local environmental changes that are important for understanding the context of hominin evolution in southern Africa. Yet most of the site's fossils were found in dumps left behind by quarry operations, and the paleoecological interpretations rest upon debatable assumptions about the original fossil provenience. We have recently initiated systematic paleoanthropological excavations at Makapansgat to recover well provenanced fossils in order to: 1) assess whether faunal successions are discernable in the Makapansgat sequence; 2) assist environmental interpretations of the site; 3) and potentially recover the oldest hominins in South Africa, roughly coincident with Australopithecus afarensis in East Africa. This paper presents a summary of our current paleoenvironmental research at the Limeworks and preliminary results of ongoing in situ excavations.  相似文献   

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《Comptes Rendus Palevol》2016,15(5):537-554
The excavations carried out from 1983 to 1985 on an Andorran hillside by the former Andorra National Artistic Heritage Archaeological Research Service revealed one of the most important Neolithic sites in the Pyrenees. Directed by Xavier Llovera and Pere Canturri, the excavations uncovered a settlement with two interesting features: 1) it was located in a high mountain area, and 2) the same place possessed numerous domestic and funerary structures. Both factors have made La Feixa del Moro a key site in the prehistory of both the Pyrenees and the western Mediterranean in general. Three decades later, a pluridisciplinary team has begun a careful review of the documentation, studied the human remains and artefacts in the graves, carried out several forms of biochemical analysis and obtained new radiocarbon determinations for the individuals exhumed in two of the three burials in stone boxes (or cists). The objective is a better understanding of the first farming communities that settled in the Pyrenees.  相似文献   

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Little information exists regarding habitat selection on oceanic islands for the introduced European rabbitOryctolagus cuniculus Linnaeus, 1758. I employed the sharp altitude gradient of one of the Canary Islands, La Palma, to analyze factors relating to rabbit abundance. I used pellet counts to assess rabbit abundance in relation to microhabitat variables during June and July of 1999 and 2001. Number of rabbits varied with grass cover in the different biotopes for both years. They were particularly abundant in biotopes at low elevation and with rich grass cover. Rabbits were more numerous in 2001 than in 1999, and selected shrub protection in places with high levels of grass cover. Areas with vegetation transformed by humans were particularly suitable for wild rabbits, in contrast to less disturbed island biotopes. Rabbit abundance was usually associated with rich grass cover, which might be a limiting factor on La Palma.  相似文献   

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This article questions the utility of the concept of urban poverty for the practice of development research and intervention. It surveys the main sociological approaches of poverty and concludes with considerations in the contet of social justice.  相似文献   

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The aim of this paper is to present the first aeromycological study of the atmosphere of the city of La Plata. Air samples were taken using a Hirst-type volumetric spore trap sampler (Lanzoni, VPPS 2000) for a period of a year (July 2000–June 2001). Seventy-nine morphological types of spores belonging to the Phyla Myxomycota, Zygomycota, Oomycota, Ascomycota, Basidiomycota, as well as anamorphs of Higher Fungi were identified. A total of 171670.21 spores were recorded, with a daily mean of 540 spores/m3. The spores were present throughout the year the study was carried out. However, there was a wide daily fluctuation in the concentration values with a tendency toward an increase during the summer months. The fungal spores were classified in three categories: abundant, having five spore types; moderate having 12 types; and low, with 62 morphological types which represent 67.2, 24.2, and 8.6%, respectively. The most representative taxa were Cladosporium cladosporioides, Leptosphaeria, Cladosporium herbarum, Coprinus, and Agaricus, the first two taxa having a high frequency during the year of study. This scientific research reveals a great diversity of morphological types in this outdoor environment, showing a strong dominance of the Imperfect Fungi, whose components have seasonal rates. By this study, the first aeromycological profile of an urban center of Argentina has been portrayed, and new information on the field of aeromycology in the country has been provided.  相似文献   

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The behaviour of Celtis airborne pollenwas studied for a period of three years(1998–2000) in the city of La Plata. The pollengrains were captured with a Lanzoni trap andthe maximum pollination period was observed tooccur during the end of winter and spring inthe three years. The annual values of pollenconcentration varied, and a significantdecrease was observed during 2000. The greatestairborne pollen record was in October with anaverage of 82.3% in relation to its totalconcentration during 1998–2000. Based on theintradiurnal behaviour analysis, it wasobserved that the maximum pollination peakoccurs at 2H when the temperaturereaches its maximum values. Considering thethree sampling years, the meteorologicalvariables that most influenced the processes of pollen emission,dispersion and transportation in the atmospherewere: maximum and minimum temperature andrainfall.  相似文献   

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City rankings that aim to measure the environmental sustainability of European cities may contribute to the evaluation and development of environmental policy of European cities. The objective of this study is to identify and evaluate the methodological characteristics of these city rankings. First, a methodology was developed to systematically identify methodological characteristics of city rankings within different steps of the ranking development process. Second, six city rankings (European Energy Award, European Green Capital Award, European Green City Index, European Soot-free City Ranking, RES Champions League, Urban Ecosystem Europe) were examined. Official websites and any methodological documents found on those websites were content analyzed using the developed methodology. Interviews with representatives of the city rankings were conducted to acquire any additional information. Results showed that the city rankings varied greatly with respect to their methodological characteristics and that all city rankings had methodological weaknesses. Developers of city rankings are advised to use the methodology developed in this study to find methodological weaknesses and improve their ranking. In addition, developers ought to be more transparent about the methodological characteristics of their city rankings. End-users of city rankings are advised to use the developed methodology to identify and evaluate the methodological characteristics of city rankings before deciding to act on ranking results.  相似文献   

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Toxocara canis is very common in dogs throughout the world. It is the primary cause of visceral larva migrans (VLM) in humans. Soil contaminated with T. canis embryonated eggs is the main source of infection of man. Our objective was to describe Toxocara seroprevalence in humans in the city of La Plata associated with some determinants such asage, presence or absence of clinical manifestations and risk factors. Blood samples were collected at random from 156 patients of different sex and age, with and without clinical symptoms compatible with the disease. The diagnostic technique ELISA test was performed with the Bordier Affinity Products Commercial Kit, using excretory-secretory Toxocara antigen with a sensitivity higher than 90%. The values were positive in 39% of the studied population. In the analysis according to age, the younger group presented significant differences with respect to the older one (Chi-square p<0.05). Positive patients presented clinical symptoms compatible with the disease (84%), and 41% presented some risk factor. The level of positivity obtained indicates a certain risk of being infects mainly in patients younger than 15 years old. The authors agree that an early identification and treatment of VLM may save a life.  相似文献   

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The first endophytic oviposition in a plant leaf from the Tatarian of European Russia (Isady locality) is formally described as Paleoovoidus rasnitsyni, sp. nov. This find supplements considerably the data on plant-insect interaction recorded in this locality.  相似文献   

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Datura (Solanaceae)is a small genus of plants that,for long, was thought to occur naturally in both the New and Old Worlds. However, recent studies indicate that all species in the genus originated in the Americas. This finding has prompted the conclusion that no species of Datura could have been present in the Old World prior to its introduction there by Europeans in the early 16th century CE. Further, the textual evidence traditionally cited in support of a pre-Columbian Old World presence of Datura species is suggested to be due to the misreading of classical Greek and Arabic sources. As a result, botanists generally accept the opinion that Datura species were transferred into the Old World in the post-Columbian period. While the taxonomic and geographic evidence for a New World origin for all the Datura species appears to be well supported, the assertion that Datura species were not known in the Old World prior to the 16th century is based on a limited examination of the pre-Columbian non-Anglo sources.We draw on old Arabic and Indic texts and southern Indian iconographic representations to show that there is conclusive evidence for the pre-Columbian presence of at least one species of Datura in the Old World. Given the systematic evidence for a New World origin of the genus, the most plausible explanation for this presence is a relatively recent but pre-Columbian (probably first millennium CE) transfer of at least one Datura species, D. metel, into the Old World. Because D. metel is a domesticated species with a disjunct distribution,this might represent an instance of human-mediated transport from the New World to the Old World, as in the case of the sweet potato (Ipomoea batatas).  相似文献   

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