254 research outputs found
FGFR1 and WT1 are markers of human prostate cancer progression
BACKGROUND: Androgen-independent prostate adenocarcinomas are responsible for about 6% of overall cancer deaths in men. METHODS: We used DNA microarrays to identify genes related to the transition between androgen-dependent and androgen-independent stages in the LuCaP 23.1 xenograft model of prostate adenocarcinoma. The expression of the proteins encoded by these genes was then assessed by immunohistochemistry on tissue microarrays (TMA) including human prostate carcinoma samples issued from 85 patients who had undergone radical prostatectomy. RESULTS: FGFR1, TACC1 and WT1 gene expression levels were associated with the androgen-independent stage in xenografts and human prostate carcinoma samples. MART1 protein expression was correlated with pT2 tumor stages. CONCLUSION: Our results suggest that each of these four genes may play a role, or at least reflect a stage of prostate carcinoma growth/development/progression
The ImageCLEF 2011 plant images classification task
International audienceImageCLEFs plant identification task provides a testbed for the system-oriented evaluation of tree species identification based on leaf images. The aim is to investigate image retrieval approaches in the con- text of crowdsourced images of leaves collected in a collaborative manner. This paper presents an overview of the resources and assessments of the plant identification task at ImageCLEF 2011, summarizes the retrieval approaches employed by the participating groups, and provides an anal- ysis of the main evaluation results
Observation of collective excitation of two individual atoms in the Rydberg blockade regime
The dipole blockade between Rydberg atoms has been proposed as a basic tool
in quantum information processing with neutral atoms. Here we demonstrate
experimentally the Rydberg blockade of two individual atoms separated by 4
m. Moreover, we show that, in this regime, the single atom excitation is
enhanced by a collective two-atom behavior associated with the excitation of an
entangled state. This observation is a crucial step towards the deterministic
manipulation of entanglement of two or more atoms using the Rydberg dipole
interaction.Comment: 5 pages, 4 figure
Global patterns and environmental drivers of forest functional composition
To determine the relationships between the functional trait composition of forest communities and environmental gradients across scales and biomes and the role of species relative abundances in these relationships. We integrated species abundance records from worldwide forest inventories and associated functional traits (wood density, specific leaf area and seed mass) to obtain a data set of 99,953 to 149,285 plots (depending on the trait) spanning all forested continents. We computed community-weighted and unweighted means of trait values for each plot and related them to three broad environmental gradients and their interactions (energy availability, precipitation and soil properties) at two scales (global and biomes). Our models explained up to 60% of the variance in trait distribution. At global scale, the energy gradient had the strongest influence on traits. However, withinbiome models revealed different relationships among biomes. Notably, the functional composition of tropical forests was more influenced by precipitation and soil properties than energy availability, whereas temperate forests showed the opposite pattern. Depending on the trait studied, response to gradients was more variable and proportionally weaker in boreal forests. Community unweighted means were better predicted than weighted means for almost all models. Worldwide, trees require a large amount of energy (following latitude) to produce dense wood and seeds, while leaves with large surface to weight ratios are concentrated in temperate forests. However, patterns of functional composition within-biome differ from global patterns due to biome specificities such as the presence of conifers or unique combinations of climatic and soil properties. We recommend assessing the sensitivity of tree functional traits to environmental changes in their geographic context. Furthermore, at a given site, the distribution of tree functional traits appears to be driven more by species presence than species abundance.Fil: Bouchard, Elise. Université du Québec a Montreal; CanadáFil: Searle, Eric B.. Université du Québec a Montreal; CanadáFil: Drapeau, Pierre. Université du Québec a Montreal; CanadáFil: Liang, Jingjing. Purdue University; Estados UnidosFil: Gamarra, Javier G. P.. Food and Agriculture Organization of the United Nations; ItaliaFil: Abegg, Meinrad. No especifíca;Fil: Alberti, Giorgio. No especifíca;Fil: Zambrano, Angelica Almeyda. No especifíca;Fil: Alvarez Davila, Esteban. No especifíca;Fil: Alves, Luciana F.. No especifíca;Fil: Avitabile, Valerio. No especifíca;Fil: Aymard, Gerardo. No especifíca;Fil: Bastin, Jean François. No especifíca;Fil: Birnbaum, Philippe. No especifíca;Fil: Bongers, Frans. No especifíca;Fil: Bouriaud, Olivier. No especifíca;Fil: Brancalion, Pedro. No especifíca;Fil: Broadbent, Eben. No especifíca;Fil: Bussotti, Filippo. No especifíca;Fil: Gatti, Roberto Cazzolla. No especifíca;Fil: Češljar, Goran. No especifíca;Fil: Chisholm, Chelsea. No especifíca;Fil: Cienciala, Emil. No especifíca;Fil: Clark, Connie J.. No especifíca;Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; ArgentinaFil: Zawiła Niedźwiecki, Tomasz. No especifíca;Fil: Zhou, Mo. No especifíca;Fil: Zhu, Zhi Xin. No especifíca;Fil: Zo Bi, Irié C.. No especifíca;Fil: Paquette, Alain. Université du Québec a Montreal; Canad
The number of tree species on Earth
One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknown. Here, based on global ground-sourced data, we estimate the total tree species richness at global, continental, and biome levels. Our results indicate that there are ∼73,000 tree species globally, among which ∼9,000 tree species are yet to be discovered. Roughly 40% of undiscovered tree species are in South America. Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains). These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness
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