944 research outputs found
Perfil polínico de un depósito glacio-lacustre, de posible edad Würm, en el macizo central de Gredos (Ávila)
El contenido polinice del perfil presentado (correspondiente a un depósito situado en la vertiente Norte de l Nacizo Central de Gredas) s upone . una nueva aportación al conocimiento de l clima y la vegetación durante e l Cuaternario reciente en el Sistema Central. La s i t uación del depósito permi t e, en base a criterios exclusivamente geomorfo l ógicos, establecer su origen y etapa f uncional durante el máximo glaciar correspondiente a l a :fase \~ ü rn.The pollen content of a deposi t from t he north of t he central region of t he Sierra de Gredos (province of Avila, Spain ) prov i des the basi s for an improvement in our knowledge of the climate and vegetation of this area during the Quaternary . Geomorphological data re l ates t his deposi t to the period of Maxi mum glaciation in the Würm phas
Datos preliminares de los análisis polínicos de las tollas ubicadas en Galve de Sorbe (Guadalajara)
Se presentan los datos palinológicos obtenidos de l as t u•'beras localizadas en Gal ve de Sorbe 1 Guadalajara) . Dichos da tos constituyen una aportación al conocimiento del cl:!.:na y de la vegetaci6n durante el Cuaternario reciente en el Sis'tema Centralwe disp:ay palinolo&ic data obtained froc11 swnc peal sited i n Galve de Sorbe (Guadalajara) . It is a contribuüon 1n order to know clima te ond ve¡¡elalíon during :ate Ouaternary in Sistema Centra
Actividad humana y dinámica de la vegetación en la Sierra de Ávila (Sistema Central Español) desde el Bronce Medio
Historia del paisaje vegetal y acción antrópica en el Cerro Genciana (Sierra de Guadarrama, Madrid) durante el Holoceno reciente
Hylleraas-Configuration Interaction calculations on the 1 ^1S ground state of helium atom
Hylleraas-Configuration Interaction (Hy-CI) calculations on the ground S
state of helium atom are presented using s-, p-, d-, and f-Slater orbitals of
both real and complex form. Techniques of construction of adapted
configurations, optimization of the orbital exponents and structure of the wave
function expansion are explored. A new method to evaluate the two-electron
kinetic energy integrals occurring in the Hy-CI method has been tested here and
compared with other methods. The non-relativistic Hy-CI values are
approximately 10 picohartree accurate, about 2.2 x 10 cm. The
Hy-CI calculations are compared with Configuration Interaction (CI) and
Hylleraas (Hy) calculations employing the same orbital basis set, same computer
code and same computer machines. The computational required times are reported.Comment: 33 pages, 9 tables, 38 references and 0 figure
Air-steam gasification of char derived from sewage sludge pyrolysis. Comparison with the gasification of sewage sludge
Air-steam gasification of char derived from fast pyrolysis of sewage sludge has been experimentally evaluated in a fluidized bed as a route towards a full recovery of energy from sewage sludge. The results have been compared with those obtained from the direct gasification of sewage sludge in order to evaluate how the previous pyrolysis stage affects the subsequent gasification process. The fixed carbon content in the solid increased after the pyrolysis stage so that heterogeneous reactions of carbon with steam or CO2 assumed greater importance during char gasification than during sewage sludge gasification. Furthermore, char gasification led to an improvement in the gas yield -calculated on a dry and ash-free basis (daf)- due to the increased concentration of carbon in the organic fraction of the solid after the pyrolysis step, with an increase in the average CO yield of about 70% -in terms of g/kg solid daf-. The reduction in the fraction of carbon which forms tar is another advantage of char gasification over the direct gasification of sewage sludge, with an average decrease of about 45%. Regarding the influence of the operating conditions, the response variables were mainly controlled by the same factors in both processes
Primeros datos polínicos de la secuencia "fuentillejo-1" de la laguna del Maar de Fuentillejo (Campo de Calatrava, Ciudad Real)
XV lnternational A.P.L.E. Symposium of Palynolog
High-level quinolone resistance is associated with the overexpression of smeVWX in Stenotrophomonas maltophilia clinical isolates
AbstractStenotrophomonas maltophilia is the only known bacterium in which quinolone-resistant isolates do not present mutations in the genes encoding bacterial topoisomerases. The expression of the intrinsic quinolone resistance elements smeDEF, smeVWX and Smqnr was analysed in 31 clinical S. maltophilia isolates presenting a minimum inhibitory concentration (MIC) range to ciprofloxacin between 0.5 and > 32 μg/mL; 11 (35.5%) overexpressed smeDEF, 2 (6.5%) presenting the highest quinolone MICs overexpressed smeVWX and 1 (3.2%) overexpressed Smqnr. Both strains overexpressing smeVWX presented changes at the Gly266 position of SmeRv, the repressor of smeVWX. Changes at the same position were previously observed in in vitro selected S. maltophilia quinolone-resistant mutants, indicating this amino acid is highly relevant for the activity of SmeRv in repressing smeVWX expression. For the first time SmeVWX overexpression is associated with quinolone resistance of S. maltophilia clinical isolates
The onset of e^+e^- -> tau^+ tau^- at threshold revisited
The precise knowledge of the onset of the cross section at the threshold is necessary for improving the accuracy of
determination of the mass from the threshold measurements. The QED
radiative corrections of relative order and , additional to
the well known Coulomb factor, are considered in the threshold region. The
correction terms of order are calculated, which contain coefficients
enhanced by large parameters. As a result it is argued that the known
corrections provide the accuracy of the description of the cross
section close to , rather than as claimed in a recent
literature. Also analytical expressions are provided for some limiting cases of
the corrections, previously calculated numerically.Comment: 16 page
Hermetic carbon coatings for electro-thermal all-fiber phase modulators
Joule effect and thermal response of several carbon-coated fibers are modelled and analysed. An electro-thermally driven all-fiber phase modulator based on these principles is proposed and a proof of concept of it is characterized. This kind of fibers could be the basis for developing all-fiber components aimed to operate in environments where the strength increase and impermeability to hydrogen diffusion guaranteed by the carbon coating is crucial.European CommissionMinisterio de Economía y CompetitividadComunidad de Madri
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