31 research outputs found
Analysis of water erosion using GIS and remote sensing for the management of protected natural environments in the south of the province of Salamanca (Spain)
Resumen del trabajo presentado al IV International Symposium on Gully Erosion, celebrado en la Universidad Pública de Navarra del 17 al 19 de septiembre de 2007.The soil is a natural resource that must be conserved in
protected natural areas since it is one of the determinant
physical supports in territorial planning because it governs
its different uses. Accordingly, specific studies must be
carried out aimed at estimating soil losses at individual
project level and at the general level of Natural Environments
in order to establish methodologies for the control and
ordering of activities, above all in protected environments
whose focus is on sustainable activities. The basic objective
should delimit different erosive forms where best it reflects
the risk of water erosion (gullies, rills) and the degree
(weak, light, important, and burden) and the processes
induced (slides, scarp, remontant erosion...) in addition the
evolution with time.Part of the work reported in this paper was financially
supported by the GCL 2005-04655/BTE and CGL 2005-01336/BTE
Projects
Reformulating Supersymmetry with a Generalized Dolbeault Operator
The conditions for N=1 supersymmetry in type II supergravity have been
previously reformulated in terms of generalized complex geometry. We improve
that reformulation so as to completely eliminate the remaining explicit
dependence on the metric. Doing so involves a natural generalization of the
Dolbeault operator. As an application, we present some general arguments about
supersymmetric moduli. In particular, a subset of them are then classified by a
certain cohomology. We also argue that the Dolbeault reformulation should make
it easier to find existence theorems for the N=1 equations.Comment: 30 pages, no figures. v2: minor correction
Nanoparticles for Multimodal Antivascular Therapeutics: Dual Drug Release, Photothermal and Photodynamic Therapy.
The poor delivery of nanoparticles to target cancer cells hinders their success in the clinical setting. In this work, an alternative target readily available for circulating nanoparticles has been selected to eliminate the need for nanoparticle penetration in the tissue: the tumor blood vessels. A tumor endothelium-targeted nanoparticle (employing an RGD-containing peptide) capable of co-delivering two anti-vascular drugs (one anti-angiogenic drug and one vascular disruption agent) is here presented. Furthermore, the nanodevice presents two additional anti-vascular capabilities upon activation by Near-Infrared light: provoking local hyperthermia (by gold nanorods in the system) and generating toxic reactive oxygen species (by the presence of a photosensitizer). RGD-targeting is shown to increase uptake by HUVEC cells, and while the nanoparticles are shown not to be toxic for these cells, upon Near-Infrared irradiation their almost complete killing is achieved. The combination of all four therapeutic modalities is then evaluated in an ex ovo fibrosarcoma xenograft model, which shows a significant reduction in the number of blood vessels irrigating the xenografts when the nanoparticles are present, as well as the destruction of the existing blood vessels upon irradiation. These results suggest that the combination of different anti-vascular therapeutic strategies in a single nanocarrier appears promising and should be further explored in the future
Tide and wind coupling in a semienclosed bay driven by coastal upwelling
The Ría de Vigo is a semi-enclosed bay in which tidal residual currents are associated with coastal upwelling events. Both upwelling and downwelling favourable winds generate a bidirectional exchange flow with the shelf – a two-layer circulation with surface waters leaving (entering) the ria and a compensating inflow (outflow) through the bottom layer under upwelling (downwelling) conditions. This vertical circulation changes the vertical density structure inside the ria. In the ria, the tide is mainly semidiurnal (M2, S2 and K2), with some energy in the diurnal band (K1). Our velocity observations show that the vertical structure of the tidal currents in the ria do not exhibit a classic barotropic profile with a bottom boundary layer beneath uniform “free-stream” flow as the tidal bottom boundary layer is affected by stratification. This links tidal circulation to the wind-driven residual circulation, since the latter also greatly helps to control the stratification. We quantify this effect by fitting tidal ellipses to observed velocities through the water column. In addition to this indirect coupling through stratification, there is a direct interaction in which velocities in the upper and bottom layers are best correlated with winds while the mid-water velocities are best correlated with tides. These wind-tide interactions are expected to play a key role in the resuspension and transport of nutrients and phytoplankton in the Ria.CTM2012-3515
The Fall of Stringy de Sitter
Kachru, Kallosh, Linde, & Trivedi recently constructed a four-dimensional de
Sitter compactification of IIB string theory, which they showed to be
metastable in agreement with general arguments about de Sitter spacetimes in
quantum gravity. In this paper, we describe how discrete flux choices lead to a
closely-spaced set of vacua and explore various decay channels. We find that in
many situations NS5-brane meditated decays which exchange NSNS 3-form flux for
D3-branes are comparatively very fast.Comment: 35 pp (11 pp appendices), 5 figures, v3. fixed minor typo
Major role of nutrient supply in the control of picophytoplankton community structure.
abstractThe Margalef´s mandala (1978) is a simplified bottom-up control model that explains how mixing and
nutrient concentration determine the composition of marine phytoplankton communities. Due to the
difficulties of measuring turbulence in the field, previous attempts to verify this model have applied
different proxies for nutrient supply, and very often used interchangeably the terms mixing and
stratification. Moreover, because the mandala was conceived before the discovery of smaller
phytoplankton groups (picoplankton <2 μm), it describes only the succession of vegetative phases of
microplankton. In order to test the applicability of the classical mandala to picoplankton groups, we
used a multidisciplinary approach including specifically designed field observations supported by
remote sensing, database analyses, and modeling and laboratory chemostat experiments.
Simultaneous estimates of nitrate diffusive fluxes, derived from microturbulence observations, and
picoplankton abundance collected in more than 200 stations, spanning widely different hydrographic
regimes, showed that the contribution of eukaryotes to picoautotrophic biomass increases with
nutrient supply, whereas that of picocyanobacteria shows the opposite trend. These findings were
supported by laboratory and modeling chemostat experiments that reproduced the competitive
dynamics between picoeukaryote sand picocyanobacteria as a function of changing nutrient supply.
Our results indicate that nutrient supply controls the distribution of picoplankton functional groups in
the ocean, further supporting the model proposed by Margalef.RADIALES (IEO
Control of tHe structure of marine phytoplAnkton cOmmunities by turbulence and nutrient supply dynamicS (CHAOS)
extended abstract del posterIn order to investigate the role of turbulence mixing on structuring marine phytoplankton communities, the CHAOS project included a multidisciplinary approach involving specifically designed field observations supported by remote sensing, database analyses, and modeling and laboratory chemostat experiments. Field observations carried out in the outer part of Ría de Vigo in summer 2013 showed that, as a result of increased mixing levels, nitrate diffusive input into the euphotic layer was approximately 4-fold higher during spring tides. This nitrate supply could contribute to explain the continuous dominance of large-sized phytoplankton during the upwelling favorable season. Simultaneous estimates of nitrate diffusive fluxes, derived from microturbulence observations, and picoplankton abundance collected in more than 100 stations, spanning widely different hydrographic regimes, showed that the contribution of eukaryotes to picoautotrophic biomass increases with nutrient supply, whereas that of picocyanobacteria shows the opposite trend. These findings were supported by laboratory and modeling chemostat experiments that reproduced the competitive dynamics between picoeukaryote and picocyanobacteria as a function of changing nutrient supply. The results derived from this project confirm that turbulence and mixing control the availability of light and nutrients, which in turn determine the structure of marine phytoplankton communities.RADIALES-20 (IEO), CHAOS (CTM 2012-30680), Malaspina-2010(CSD2008-00077
Aportaciones a la flora de Galicia, VIII
Se citan 37 plantas de variado interés para la flora gallega. Se incluyen 8 novedades de carácter regional
(Pteris incompleta Cav., Potentilla recta L., Myriophyllum spicatum L., Solanum sisymbrifolium Lam., Knautia
integrifolia (L.) Bertol., Senecio inaequidens DC. Melica arrecta G. Kunze y Stipa clausa Trab.), 17 novedades
provinciales (Vandenboschia speciosa (Willd.) G. Kunkel, Ranunculus bupleuroides Brot., Silene niceensis All.,
Armeria transmontana (Samp.) Lawr., Alcea rosea L., Crambe hispanica L., Rorippa microphylla (Rchb.) Hyl.,
Saxifraga lepismigena Planellas, Cytisus commutatus subsp. merinoi Laínz & M. Laínz, Galega officinalis L.,
Melilotus spicatus (Sm.) Breistr., Calystegia silvatica (Kit.) Griseb., Orobanche hederae Baucher ex Duby, Aegilops
triuncialis L., Eleusine tristachya (Lam.) Lam., Gagea nevadensis Boiss. y Paradisea lusitanica (Cout.)
Samp.) y 12 de interés corológico pero que no suponen novedad gallega o provincial (Lycopodiella inundata (L.)
Holub., Corydalis cava (L.) Schweigg. & Körte, Quercus cerris L., Genista sanabrensis Valdés Berm., Castrov.
& Casaseca, Oenothera speciosa Nutt., Ligustrum vulgare L., Stachys sylvatica L., Antirrhinum meonanthum
Hoffmanns. & Link, Cynara cardunculus L., Nardus stricta L., Gagea pratensis (Pers.) Dumort. y Narcissus
rupicola Dufour). Como en anteriores aportaciones, cada taxon va acompañado de diversos comentarios que
indican su relevancia corológica o ecológica
Aportaciones a la flora de Galicia, IX
En este trabajo se mencionan 53 plantas de diverso interés para la flora de Galicia o zonas próximas. Se
incluyen 3 novedades para España (Sesamoides minor (Lange) O. Kuntze x S. purpurascens (L.) G. López, Hedychium
gardnerianum Sheppard ex Ker-Gawler y Oxalis incarnata L.) y otra para Portugal (Bromus hordeaceus
L. subsp. ferronii (Mabille) P.M. Smith), 3 novedades regionales (Oxalis incarnata L., Antirrhinum latifolium
Mill., Sisyrinchium striatum Mill.), 16 novedades provinciales (Ranunculus bulbosus L. subsp. aleae (Willk.)
Rouy & Fouc. var. adscendens (Brot.) Pinto da Silva, Ranunculus peltatus subsp. peltatus var. microcarpus
Meikle, Dianthus laricifolius subsp. merinoi (M. Laínz) M. Laínz, Spartium junceum L., Sanicula europea
L., Tordylium maximum L., Euphorbia flavicoma DC. subsp. occidentalis M. Laínz, Campanula medium L.,
Centaurea melitensis L., Festuca durandoi Clauson in Billot subsp. capillifolia (Pau ex Willk.) Rivas Ponce,
Cebolla & M.B. Crespo var. livida (Hack.) Rivas-Ponce, Cebolla & M.B. Crespo, Phalaris minor Retz, Carex
distans L., Carex umbrosa Hornem. subsp. umbrosa) y otras 40 de interés diverso, bien ecológico, corológico
o taxonómico. También, y a la luz de más información, eliminamos del catálogo de la flora vascular de Galicia
Iberis contracta subsp. welwitschii (Boiss.) Moreno y Arctium lappa L. Se lectotipifica Euphorbia polygalifolia
subsp. hirta (Lange) M. Laínz y Senecio doria var. subintegrum Merino
Validación del "Cuestionario de ansiedad social para adultos" (CASO-A30) en universitarios españoles: similitudes y diferencias entre carreras universitarias y comunidades autónomas
Resumen: El objetivo de este trabajo es presentar las propiedades psicométricas del ?Cuestionario de ansiedad social para adultos? (CASO-A30) con universitarios y analizar las diferencias y similitudes en ansiedad social en esta muestra. Participaron 15504 estudiantes de 20 carreras universitarias de 17 comunidades autónomas españolas a los que se les aplicó el CASO-A30 y la ?Escala de ansiedad social de Liebowitz, versión de autoinforme? (LSAS-SR). Se obtuvieron cinco dimensiones a través de diversos análisis factoriales y de ecuaciones estructurales del CASO-A30: ?Hablar en público/Interacción con personas de autoridad?, ?Interacción con desconocidos?, ?Interacción con el sexo opuesto?, ?Expresión asertiva de molestia, desagrado o enfado? y ?Quedar en evidencia o en ridículo?. La consistencia interna fue de 0,91 y su validez concurrente (con la LSAS-SR) de 0,66. Se hallaron diferencias significativas entre hombres y mujeres, pero escasas diferencias entre las comunidades autónomas y las carreras. Estos resultados confirman la estructura pentafactorial y las buenas propiedades psicométricas del CASO-A30, que lo convierten en un instrumento adecuado para la evaluación de la ansiedad social en universitarios, tanto generalizada como específica, cuidando las diferencias de sexo.Abstract: This work presents the psychometric properties of the Social Anxiety Questionnaire for Adults (SAQ-A30) with university students and analyses the differences and similarities in social anxiety in the sample. The 15,504 participants, students of 20 degree subjects in 17 Spanish Autonomous Community regions, were applied the SAQ-A30 and the ?Liebowitz Social Anxiety Scale-Self Report? (LSAS-SR). A five-factor structure was obtained through several factor analyses as well as an exploratory structural equation modeling of the SAQ-A30: ?Speaking in public/Talking with people in authority?, ?Interactions with strangers?, ?Interactions with the opposite sex?, ?Assertive expression of annoyance, disgust or displeasure?, and ?Criticism and embarrassment?. Internal consistency was 0.91 and concurrent validity (paired with LSAS-SR) was 0.66. Significant differences were found between males and females, but there was scarce difference between regions and subjects studied. These results confirm the five-factor structure and the good psychometric characteristics of the SAQ-A30, which make it a suitable instrument for assessing both general and specific social anxiety in universities, taking into account sex differences.Este estudio ha sido financiado parcialmente por la Fundación para el Avance de la Psicología Clínica Conductual (FUNVECA), el Ministerio de Ciencia y Tecnología de España (BSO2003-07029/PSCE) y el Fondo Europeo de Desarrollo Regional (FEDER)