Improvement of scanning tunneling microscopy resolution with H-sensitized tips

Recent scanning tunneling hydrogen microscopy (STHM) experiments on PTCDA (perylene-3,4,9,10- tetracarboxylic-3,4,9,10-dianhydride)/Au(111) have shown unprecedented intramolecular and intermolecular spatial resolution. The origin of this resolution is studied using an accurate STHM theoretical simulation technique that includes a detailed description of the electronic structure of both the tip and sample. Our results show that H2 molecules are dissociated on the Au tip; the adsorbed H atoms change the density of states at the Fermi level (EF) of the tip, increasing its p-orbital character and reducing the s-orbital contribution. Also, due to the interaction with the H-decorated tip, EF is shifted to the middle of the PTCDA lowest unoccupied molecular orbital peak, increasing dramatically the density of states of the sample at EF. These effects give rise to the enhanced STHM resolutionThis work is supported by Spanish MICIIN under Contract No. FIS2010-16046, the CAM under Contract No. S2009/MAT-1467, and the European Project MINOTOR (Grant No. FP7-NMP-228424). J. I. M. acknowledges funding from Spanish MICINN through Juan de la Cierva Program, E. A. the financial support by Consejería de Educación de la CAM, FSE, and European Project MINOTOR, and C. G. the CSIC JA

DATOS PRELIMINARES SOBRE EL CICLO NICTIMERAL DE PHLEBOTOMUS PERNICIOSUS NEWSTEAD, 1911 Y PHLEBOTOMUS SERGENTI PARROT, 1917 (DIPTERA, PSYCHODIDAE)

Studies carried out on night activity of sandflies in an endemic area of leishmaniasis have shown the night cycle of the most abundant species: Phlebotomus perniciosus Newstead, 1911 and Phlebotomus sergenti Parrot, 1917. This cyle is directly related to environmental conditions and physiological stage of females. So, warm and dry conditons allow sandflies activity is continued all night long. With lower temperatures and higher relative humidity values sandflies go out from their resting sites in waves. The higher densities, measured in sandflies per hour, have been reached from 21 to 24 p.m.; so, this is the most important epidemiological risk period for dispersion of leishmaniasis, because 95 per cent of females have not fed yet and, accordingly, they should be more active to find a host.El estudio del ciclo nictimeral de los flebotomos en un foco de leishmaniasis en el sudeste de la Península Ibérica ha puesto de manifiesto la actividad nocturna de las especies más abundantes: Phlebotomus perniciosus Newstead, 1911 and Phlebotomus sergenti Parrot, 1917. El ciclo de actividad nocturna de estos dípteros está directamente relacionada con las condiciones microambientales y con el estado fisiológico de las hembras. De forma que temperaturas elevadas y ambientes secos permiten un desarrollo de la actividad de los flebotomos de forma continuada a lo largo de toda la noche. Temperaturas más bajas y humedad relativa alta favorecen que la actividad de estos dípteros sea en oleadas. Las mayores densidades, medidas en flebotomos capturados por hora, se alcanzan entre las 21 y las 24 horas p.m., por tanto este es el periodo de mayor riesgo para la dispersión de la leishmaniasis, debido a que el 95% de las hembras no se habían alimentado todavía y éstas se muestran más activas para satisfacer sus necesidades alimentarias

CARACTERES MORFOLÓGICOS DE INTERÉS TAXONÓMICO DE LOS FLEBOTOMOS (DIPTERA, PSYCHODIDAE) DE LA PENÍNSULA IBÉRICA

El estudio de un elevado número de ejemplares de flebotomos de la península ibérica, ha permitido poner de manifiesto una serie de caracteres morfológicos que presentan variación con las especies y que tienen interés taxonómico. Estos caracteres son los filamentos genitales y noveno segmento de los machos y la región distal de los conductos de las espermatecas y la estructura de las faringes de las hembras, observadas tras su disección fina

Geochemical characterization of the mining district of Linares (Jaen, Spain) by means of XRF and ICP-AES

Linares (Jaen, Spain) has been subjected to an intense mining and metallurgic activity during 2500 years. Basically, lead and silver have been extracted from galena; as well as copper and zinc. Different studies have been conducted to evaluate trace element concentrations to obtain relationships with anthropogenic and geologic factors. The analytical results of these studies have been obtained with ICP-AES. This analytical technique is relatively expensive and inaccessible in zones with scarce economic means. In this study, XRF analyses have been conducted and the obtained results are presented, as well as a comparison with the previously obtained ICP results. In both cases, a cluster analysis has been made to try to identify the same relations in the target area. 5 groups have been identified, mainly related with lithology. Only 10 of the 122 grid squares (each one of 1 km2) are classified in different groups if the cluster analysis is conducted with XRF results or ICP results. ICP classifies better where these grid squares are located, mostly, in contact zones of different lithologies

ESTUDIO DE LAS POBLACIONES DE FLEBOTOMOS (DIPTERA, PSYCHODIDAE) DE LA COMUNIDAD DE MADRID (ESPAÑA)

A study dealing with phlebotomine sandflies in the Madrid community (Central Spain) has been carried out. A total of 31.161 specimens belonging to seven species were capturated. The two species Sergentomyia minuta (Rondani, 1843) and Phlebotomus perniciosus Newstead, 1911 are the most abundant and widespread among these. The presence of Phlebotomus papatasi (Scopoli, 1786), Phlebotomus longicuspis Nitzulescu, 1930 and Phlebotomus langeroni Nitzulescu, 1930 have been reported for the first time in the Madrid province. Some aspects dealing with the sandflies populations such as specific richness and frecuence as well as interspecific affinity and specific diversity are treated. These results provide information about the structure and dynamics of phlebotomine sandflies populations in the Madrid province.En el estudio entomológico sobre flebotomos, llevado a cabo en la Comunidad de Madrid, se capturó un total de 31.161 ejemplares pertenecientes a 7 especies. Entre estas especies cabe destacar Sergentomyia minuta (Rondani, 1843) y Phlebotomus perniciosus Newstead, 1911, como las especies más abundantes y comunes. Así mismo se aportan tres nuevas especies a la lista de flebotomos de la provincia de Madrid: Phlebotomus papatasi (Scopoli, 1786), Phlebotomus longicuspis Nitzulescu, 1930 y Phlebotomus langeroni Nitzulescu, 1930. Se estudian diferentes aspectos de las comunidades de flebotomos: riqueza específica, frecuencia, convivencia, afinidad interespecífica y diversidad específica, lo que permite conocer, en parte, la estructura de dichas comunidades

C6H6/Au(111): Interface dipoles, band alignment, charging energy, and van der Waals interaction

The following article appeared in Journal of Chemical Physics 134.4 (2011): 044701 and may be found at http://scitation.aip.org/content/aip/journal/jcp/134/4/10.1063/1.3521271.We analyze the benzene/Au(111) interface taking into account chargingenergy effects to properly describe the electronic structure of the interface and van der Waals interactions to obtain the adsorption energy and geometry. We also analyze the interface dipoles and discuss the barrier formation as a function of the metal work-function. We interpret our DFT calculations within the induced density of interface states (IDIS) model. Our results compare well with experimental and other theoretical results, showing that the dipole formation of these interfaces is due to the charge transfer between the metal and benzene, as described in the IDIS model.This work is supported by Spanish MICIIN under Contracts No. MAT2007-60966 and No. FIS2010-16046, the CAM under Contract No. S2009/MAT-1467, and the European Project MINOTOR (Grant No. FP7-NMP-228424). E.A. gratefully acknowledges financial support by the Consejería de Educación of the CAM and the FSE. J.I.M. acknowledges funding from Spanish MICINN through Juan de la Cierva Program

Servidor de datos y página web para el aprendizaje de SIG en la ingeniería forestal

Los Sistemas de Información geográfica (SIG) son una herramienta de trabajo habitual en el ámbito de la ingeniería forestal, tanto en la faceta de redacción de proyectos, como en la investigación sobre el medio ambiente y el territorio. Cada vez hay más información cartográfica disponible desde servidores de diferentes instituciones, por lo que consideramos que es muy útil contar con una herramienta de organización de la información. En el trabajo que se presenta, se pretende proporcionar a los estudiantes e investigadores en materia forestal un portal que contenga información actualizada y ordenada sobre los recursos existentes compatibles con los SIG. Por tanto constituiráuna herramienta de apoyo que facilitarála fase de documentación, búsqueda de datos compatibles y aprendizaje de las herramientas que sirven de base para el desarrollo de cualquier trabajo técnico o de investigación relacionado con el medio ambiente y el territorio que se apoye en los SIG

Morfología y erosión de los suelos de suroeste de Sierra Nevada (Granada)

En el presente estudio se reflejan una serie de características morfológicas de Leptosoles, Regosoles, Calcisoles, Luvisoles y Cambisoles localizados al SW de Sierra Nevada, así como los parámetros que inciden en su degradación erosiva ( erosión hídrica y erodibilidad eólica) y las fluctuaciones de la intensidad de éstas en cada caso.In the study that we present are showed several morphological characteristics of Leptosols, Regosols, Calcisols, Luvisols and Cambisols located at SW of Sierra Nevada, as well the parameters which have incidence on their erosive degradation (hydric erosion and eolic erosibity) and their intensity fluctuations for each case

Quantum Noise Limits for Nonlinear, Phase-Invariant Amplifiers

Any quantum device that amplifies coherent states of a field while preserving their phase generates noise. A nonlinear, phase-invariant amplifier may generate less noise, over a range of input field strengths, than any linear amplifier with the same amplification. We present explicit examples of such nonlinear amplifiers, and derive lower bounds on the noise generated by a nonlinear, phase-invariant quantum amplifier.Comment: RevTeX, 6 pages + 4 figures (included in file; hard copy sent on request