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Influence of environmental factors on the development of L. taurica on pepper genotypes To our knowledge, the effects of certain environmental factors, as well as those of host genotype on the development of Leveillula taurica on pepper have not been extensively investigated. To study effects of the above factors on the development of this parasite, two Capsicum genotypes (‘Yolo Wonder' and ‘line 815’) have been tested and compared under different light and relative humidity conditions. In vitro, optimal light intensity for spore germination was situated between 20 and 80 μE/m2/s, and for the growth of germ tubes it was 20 μE/m2/s. In vivo, under continous darkness during 20 days, the different organs of the hosts were only slightly affected. Under light conditions, during 20 days after inoculation, the highest infection level on leaves was observed at 20 μE/m2/s, (60 % of leaves) while with the cotyledons it was observed between 20–80 μE/m2/s. Effects of relative humidity on the development of this parasite were also studied on ‘Yolo Wonder’ and ‘line 815′. With relative humidity below 50 %, 60 % of ‘Yolo Wonder’ plants and 33 % of ‘line 815’ were infected. Under conditions of saturated relative humidity, the level of infection was the inverse, i. e. 13 and 55 %, respectively. Moreover, ‘Yolo Wonder’ plants were found more or less susceptible to infection with L. taurica during their different development stages. At the cotyledon stage all plants were infected. After this stage, up to flowering, susceptibility depended on the physiological age of the leaves. First leaves (older leaves) were not infected, while young ones near the apex became progressively susceptible.  相似文献   

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The site of Longgupo, discovered in 1984, is located south of the crossing of the Three Gorges of the Yangtze, in the eastern part of Chongqing Province. Situated on the limestone slope of the Miaoyu Valley, three excavation campaigns have been carried out since 1985. The first two seasons took place from 1985–1988 and 1997–1998, directed by W.B. Huang and the last campaign from 2003–2006 by E. Boëda and Y.M. Hou. After the first two campaigns, the presence of several bones, with an estimated age of 1.9 My, notably including a mandible fragment attributed to a hominid2 and the discovery of more than 20 lithic artifacts incited not only great interest in the scientific community, but controversy as well since these data contradicted diffusion models of the first hominids out of Africa. Paleoanthropological data often being privileged over other data, including lithic artifacts, the anthropic nature of the site was contested. Yet the few artifacts from the initial excavations irrefutably demonstrate their manufacture by humans, in particular those in exogenous stone. To definitively re-establish the authenticity of this site by applying the latest investigative methods, a new Franco-Chinese campaign was organized. The objective of the 2003–2006 field seasons focused on understanding and analysis of the archaeological data in their geomorphological and stratigraphic contexts.  相似文献   

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Sensitiveness of seedlings of Triticinae against the pathogenic agens of Pseudocercosporella herpotrichoides (Fron) Deighton The study of the sensitiveness of 16 varieties or lines of Triticinae against two races of Pseudocercosporella herpotrichoides shows that, whatever the strain used, the importance of the attacks is much less serious on seedlings of Ae. ventricosa no. 11, Ae. squarrosa no. 15, Ae. squarrosa no. 33 and Roazon, Roazon was the least sensitive among the Triticum. It is obvious that Ae. ventricosa is the most resistant one in all varieties or lines used.  相似文献   

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The Baume of Montclus is located in the Cèze valley (Gard). This site gave its name to a prehistoric tool-age, the Montclusian, which parted from the Sauveterrian. Middle and Upper Montclusian are present in Montclus, unlike the Lower Montclusian. The Montclusian industry, which starts here in about 8000 BP, includes a very high proportion of hypermicrolithes. It is followed by a Castelnovian industry from around 7000 BP. This one features very different Montclusian, showing thus a break. The Castelnovian survives in Montclus while the Cardial is already settled in Châteauneuf-les-Martigues and sites around the Ardèche river. After these Montclusian levels appear Cardial and Chassean layers. Neolithisation has been very gradual here, affecting tools first before the arrival of ceramic, around 6500 BP. What is the origin of Montclusian? And what could have become? Its origin might be further west with the Causses and Languedoc, where levels are rather similar. The Sauveterrian origin has long been established. But research shows a great diversity among the Sauveterrian originated industries. What the Montclusian was going to become is to discovered from the Lower Montclusian, quite original, and which should be found in other site. Montclusian might be on the geographic and cultural boderline of 2 districts: one being located west of the Rhône river, influenced by Sauveterrian, and which gave birth to Montclusian, the other east of the Rhône river bears witness to Castelnovian.  相似文献   

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The “Earth of fortified settlement” is one of the last big discoveries of the end of the XXth century. Situated on the oriental slopes of the mounts of Ural, fortified settlement, date the Middle Bronze Age. These strengthened structures are particular in the archaeology of steppes. They were built according to geometrical plans, Cities in oval being the most ancient, the rectangular cities being the most recent. The most remarkable are together of strengthened structures appropriate for the culture of Sintachta-Arkaïm. This city distinguishes itself from the others by the unique integrity of the works of fortification and by the graves which are connected to these last ones. Situated on a prominence, Arkaim consists of two defensive walls, maybe of a third, the rampart and the ditch. The space between the defensive walls was occupied by the houses of shape trapezoidale and directed as beams to the center of the city. The center of the city, the rectangular shape, was not built and formed a place where foyers were found. Complex entrances were at the four corner of the city. The excavations of fortified settlement and graves allowed to have an idea on the level of development of the everyday life at the time of the Middle Bronze Age in transouraliennes plains.  相似文献   

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In 2011, the prostate cancer positions itself clearly like a problem of public health. The radiotherapy has shown these twenty last years significant improvements with the advent of the three-dimensional conformation radiotherapy as a standard in the treatment of the adenocarcinoma prostate cancer, and now with the contribution of the modulation of intensity which makes it possible to consider an increment of amount on estimated target volume without toxicity added to the organs at risks. Radio-hormonotherapy association for high-risk cancers also went to current practice. The nuclear medicine through new tracers and new indications probably will allow the experts dealing with these patients to better define the indications and to better distinguish the patients who will profit authentically from a therapeutic strategy more than of another, and even to associate them…  相似文献   

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In this paper, we will examine the foundations of Western representation of Paleolithic art at the end of the nineteenth century. Taking the period of 1864-1902 into account, we will prove the leading role of analogy between “modern primitive societies” and “prehistoric societies” in the very definition of “primitive art”. According to us, the representation of the “primitive artist” at that time was largely based in comparison between art which came from modern primitive societies living in Africa, Australia or America, and prehistoric art which was authenticated at about 1865. Through this examination, we will show the way in which analogy functions as a main category in the construction of scientific knowledge.  相似文献   

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