2,479 research outputs found

    The genus Huperzia (Lycopodiaceae) in the Azores and Madeira

    Get PDF
    The taxonomy and nomenclature of the genus Huperzia Bernh. in the Azores and Madeira have been reviewed. Plants collected in the Azores and Madeira were characterized morphologically. The independence between two endemic species common to Madeira and the Azores Islands – Huperzia suberecta (Lowe) Tardieu and Huperzia dentata (Herter) Holub – is clearly shown. A clear-cut morphological separation between these taxa and Huperzia selago (L.) Bernh. ex Schrank & Mart. of continental Europe is established

    The genus Huperzia (Lycopodiaceae) in the Azores and Madeira

    Get PDF
    The taxonomy and nomenclature of the genus Huperzia Bernh. in the Azores and Madeira have been reviewed. Plants collected in the Azores and Madeira were characterized morphologically. The independence between two endemic species common to Madeira and the Azores Islands – Huperzia suberecta (Lowe) Tardieu and Huperzia dentata (Herter) Holub – is clearly shown. A clear-cut morphological separation between these taxa and Huperzia selago (L.) Bernh. ex Schrank & Mart. of continental Europe is established

    Differentiation of Trichuris species using a morphometric approach

    Get PDF
    Trichuris trichiura is a nematode considered as the whipworm present in humans and primates. The systematics of the genus Trichuris is complex. Morphological studies of Trichuris isolated from primates and humans conclude that the species infecting these hosts is the same. Furthermore, numerous molecular studies have been carried out so far to discriminate parasite species from humans and Non-Human Primates using molecular techniques, but these studies were not performed in combination with a parallel morphological study. The hypothesised existence of more species of Trichuris in primates opens the possibility to revise the zoonotic potential and host specificity of T. trichiura and other putative new species of whipworms. In the present work, a study of Trichuris Roederer, 1761 (Nematoda:Trichuridae) parasitizing C. g. kikuyensis, P. ursinus, Macaca sylvanus, Pan troglodytes, and Sus scrofa domestica has been carried out using modern morphometric techniques in order to differentiate populations of Trichuris isolated from four species of captive NHP from different geographical regions, and swine, respectively. The results obtained revealed strong support for geometrical morphometrics as a useful tool to differentiate male Trichuris populations. Therefore, morphometrics in combination with other techniques, such as molecular biology analyses, ought to be applied to further the differentiation of male populations. On the other hand, morphometrics applied to female Trichuris species does not seem to contribute new information as all the measurements combinations of obtained from females always showed similar resultsMinistry of Economy,Industry and Competitiveness(CGL2017-83057)FEDER funds, the Junta de Andalucía (BIO-338)V Plan Propio de Investigación of the University of Sevill

    El fracaso de Copenhague desde la teoría de juegos

    Get PDF
    Los acuerdos medioambientales de carácter supranacional parecen “condenados” a no funcionar debido, fundamentalmente, a la característica del propio medio ambiente como bien público global. Si uno de los agentes implicados toma la iniciativa con movimientos hacia un cambio tecnológico, más respetuoso en términos medioambientales y más eficiente en términos energéticos, podría cambiar los resultados y lograr la buscada reducción en los niveles de contaminación. La UE ha adoptado esa posición pero la cumbre de Copenhague, lejos de corroborar que el resto de países seguirán la estrategia iniciada por la UE, ha sido un fracaso en términos de mayor compromiso por parte de países que, de momento, siguen fuera del protocolo, básicamente EEUU. El objetivo de este trabajo es analizar qué circunstancias han podido propiciar (intencionadamente o no) el fracaso en la búsqueda de apoyos en la cumbre de Copenhague

    Spatial and temporal variability of CO2 emisions in soils under conventional tillage and no-till farming

    Get PDF
    Agricultural soils can act as a carbon sink depending on the soil management practices employed. As a result of this functional duality, soil management systems are present in international documents relating to climate change mitigation. Agricultural practices are responsible for 14% of total greenhouse gas emissions (GHG’s) (MMA, 2009)(1). Conservation agriculture (CA) is one of the most effective agricultural systems for reducing CO2 emissions, as it increases the sequestration of atmospheric carbon in the soil. In order to assess the performance of CA in terms of CO2 emissions, a field trial was conducted comparing soil derived CO2 fluxes under No-till (NT) farming and under conventional tillage. Three pilot farms were selected in the cereal-growing area of southern Spain, located in Las Cabezas de San Juan (Seville), Carmona (Seville) and Cordoba. Each pilot farm comprises six experimental plots with an approximate area of five hectares; three of the six plots implement CA practices, while the other three use conventional tillage techniques. The subdivision of each tillage system into 3 plots allowed the simultaneous cropping of the three crops of the wheat-sunflower-legume rotation each year. Results showed that carbon dioxide emissions were 31 to 91% higher in tilled soils than in untilled soils, and that there was a great seasonal variability of CO2 emissions, as weather conditions also differed considerably for the different sampling periods. In all cases, the CO2 fluxes emitted into the atmosphere were always higher when soil was subject to conventional tillage
    corecore