780 research outputs found

    “El fin de un enigma”, una nueva subtribu y novedades nomenclaturales en Asclepiadeae (Apocynaceae: Asclepiadoideae)

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    Se propone Topea H. A. Keller como nuevo nombre para el género Aenigma H. A. Keller (Apocynaceae) por prexistir un homónimo fonético. Además, sobre la base de estudios de filogenia molecular se describe dentro de la tribu Asclepiadeae a la nueva subtribu monogenérica Topeinae H. A. Keller & Liede, endémica del Cono Sur de América del SurA new name, Topea H. A. Keller, is proposed for the genus Aenigma H. A. Keller (Apocynaceae) because there is a preexisting phonetic homonym. In addition, based on molecular phylogenetic studies, the new, monogeneric subtribe Topeinae H. A. Keller & Liede, endemic to the southern cone of South America, is here described within the tribe Asclepiadeae.Fil: Keller, Hector Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentina. University of Bayreuth; AlemaniaFil: Liede Schumann, Sigrid. University of Bayreuth; Alemani

    Left-right symmetry and heavy particle quantum effects

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    We have renormalized a classical left-right model with a bidoublet, and left and right triplets in the Higgs sector. We focus on oblique corrections and show the interplay between the top quark, heavy neutrinos and Higgses contribution to the muon Δr\Delta r parameter. In the SM, custodial symmetry prevents large oblique corrections to appear. Although in LR models there is no such symmetry to make vanish the quadratically diverging terms, we have shown, that heavy Higgses contributions to Δr\Delta r are under control. Also the top contribution to Δr\Delta r, quite different from that in the SM, is discussed. However, heavy neutrinos seem to give the most important contributions. From oblique corrections, they can be as large as the SM top one. Moreover, vertex and box diagrams give additional non-decoupling effects and only concrete numerical estimates are able to answer whether the model is still self-consistent.Comment: 23 pages, 3 figure

    Diversity of Diptera families that pollinate Ceropegia (Apocynaceae) trap flowers: An update in light of new data and phylogenetic analyses

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    Pollination by flies (Diptera) has been important to the diversification and ecology of the flowering plants, but is poorly understood in contrast to pollination by other groups such as bees, butterflies and birds. Within the Apocynaceae the genera Ceropegia and Riocreuxia temporarily trap flies, releasing them after a fixed, species-specific period of time, during which pollination and/or pollen removal occurs. This “trap flower” pollination system shows convergent evolution with unrelated species in other families and fascinated Stefan Vogel for much of his career, leading to ground-breaking work on floral function in Ceropegia (Apocynaceae). In this new study we extend the work of the latest broad analysis published by some of the authors (Ollerton et al., 2009 − Annals of Botany). This incorporates previously unpublished data from India and Africa, as well as recently published information, on the diversity of po llinators exploited by Ceropegia. The analyses are based on a more accurate phylogenetic understanding of the relationships between the major groups, and significantly widens the biogeographic scope of our understanding of fly pollination within Ceropegia. Information about the pollinators of 69 taxa (species, subspecies and natural varieties) of Ceropegia is now available. Twenty five families of Diptera are known to visit the flowers of Ceropegia, of which sixteen are confirmed as pollinators. Most taxa are pollinated by species from a single family. Overall, there were no major biogeographic differences in the types of Diptera that were used in particular regions, though some subtle differences were apparent. Likewise there were no differences between the two major clades of Ceropegia, but clear differences when comparing the range of Diptera exploited by Ceropegia with that of the stapeliads. This clade, one of the largest in the Asclepiadoideae, is a fascinating example of a species radiation driven by an apparently relatively uniform set of pollinators

    The Apocynaceae TEN (Taxonomic Expert Network)

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    Mutation analysis of BRCA1 and BRCA2 genes in Iranian high risk breast cancer families

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    Background: Telomerase is a ribonucleoprotein enzyme that synthesises telomeres after cell division and maintains chromosomal stability leading to cellular immortalization. Telomerase has been associated with negative prognostic indicators in some studies. The present study aims to detect any association between telomerase sub-units: hTERT and hTR and the prognostic indicators including tumour's size and grade, nodal status and patient's age. Methods: Tumour samples from 46 patients with primary invasive breast cancer and 3 patients with benign tumours were collected. RT-PCR analysis was used for the detection of hTR, hTERT, and PGM1 (as a housekeeping) genes expression. Results: The expression of hTR and hTERT was found in 31(67.4%) and 38 (82.6%) samples respectively. We observed a significant association between hTR gene expression and younger age at diagnosis (p = 0.019) when comparing patients ≤ 40 years with those who are older than 40 years. None of the benign tumours expressed hTR gene. However, the expression of hTERT gene was revealed in 2 samples. No significant association between hTR and hTERT expression and tumour's grade, stage and nodal status was seen. Conclusion: The expression of hTR and hTERT seems to be independent of tumour's stage. hTR expression probably plays a greater role in mammary tumourogenesis in younger women (≤ 40 years) and this may have therapeutic implications in the context of hTR targeting strategies

    “El fin de un enigma”, una nueva subtribu y novedades nomenclaturales en Asclepiadeae (Apocynaceae: Asclepiadoideae)

    Get PDF
    A new name, Topea H. A. Keller, is proposed for the genus Aenigma H. A. Keller (Apocynaceae) because there is a preexisting phonetic homonym. In addition, based on molecular phylogenetic studies, the new, monogeneric subtribe Topeinae H. A. Keller & Liede, endemic to the southern cone of South America, is here described within the tribe AsclepiadeaeSe propone Topea H. A. Keller como nuevo nombre para el género Aenigma H. A. Keller (Apocynaceae) por prexistir un homónimo fonético. Además, sobre la base de estudios de filogenia molecular se describe dentro de la tribu Asclepiadeae a la nueva subtribu monogenérica Topeinae H. A. Keller & Liede, endémica del Cono Sur de América del Su

    Caa, un nuevo género sudamericano de Gonolobinae (Apocynaceae: Asclepiadeae: Asclepiadoideae)

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    The phylogenetic analysis of the subtribe Gonolobinae allowed to determine the position of Matelea balansae Morillo & Fontella, a taxon that was not related to the clade of the genus Matelea Aubl. sensu stricto, nor was grouped into other generic clades. This leads to the foundation of a new monotypic genus, Caa H. A. Keller & Liede. Morphological information, complementary to the original diagnosis of the species, is included.El análisis filogenético de la subtribu Gonolobinae permitió determinar la posición de Matelea balansae Morillo & Fontella, taxón que no resultó afín al clado del género Matelea Aubl. sensu stricto, ni tampoco se agrupó dentro de otros clados genéricos. Ello propicia la conformación de un nuevo género monotípico, Caa H.A. Keller & Liede. Se incluye información morfológica complementaria a la diagnosis original de la especie.Fil: Keller, Hector Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Liede Schumann, Sigrid. University of Bayreuth; Alemani

    Tarvitsemme tieliikennemuseon

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    Humanistin mietteitä tekniikan opetuksesta

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    Tekniikka ja tekniikan museointi

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