Distribución de la brioflora en el gradiente vertical (suelo-dosel) y la selectividad de habitats en Tarapacá (Amazonas, Colombia)

En los diferentes tipos de paisaje del corregimiento de Tarapacá (Amazonas-Colombia) se estudió la distribución vertical de los briófitos sobre los forofítos, encontrándose que alrededor del 41% de las especies son exclusivas del dosel y el 35% exclusivas del sotobosque. Además, se analiza la selectividad de las especies de briófitos por diferentes tipos de hábitats (base de tronco, corteza baja, corteza alta, ramas bajas, ramas altas, epífilos, roca, hojarasca, suelo y troncos caídos en descomposición) y sus formas de crecimiento. En todos los tipos de paisaje, la selectividad de la brioflora fue mayor sobre la corteza baja de los árboles y los hábitats del dosel (hojas y ramas del dosel a más de 18 m de altura sobre el suelo), con las formas de crecimiento más comunes (felpas lisas, felpas rugosas e hilos) y el mayor número de especies (especialistas y/o generalistas). Los resultados obtenidos para Tarapacá, fueron comparados con otras regiones similares.In the different types of landscape of Tarapacá (Amazonas-Colombia) the vertical distribution of the bryophytes was studied, being found that around 41% of the species are exclusive of the canopy and 35% exclusive of the understory. Furthermore, there is analyzed the selectivity of the bryophytes species for different types of habitats (trunk, low bark, high bark, low branches, high branches, foliicolous, rocks, soil and rotten trunks fallen down) and their growth forms. In all the landscape types, the selectivity of the bryophytes was greater for the low bark and the habitats of the canopy (leaves and canopy branches more than 18m high), with the more common growth forms (smooth mats, rough mats and threads) and the larger number of species („Specialist“ o „Generalist“). The results obtained for Tarapacá were compared with other similar regions

Commercial scale membrane distillation for solar desalination

Abstract Membrane distillation is an attractive technology for solar-powered decentralized desalination that has not yet reached commercial breakthrough on a large scale. The main barriers are energy consumption and cost. Since the latter are mostly related to the former, thermal energy efficiency is key to assessing the potential of the different available membrane distillation systems at a commercial scale. As discussed here, existing membrane distillation technologies use mostly flat sheet membranes in plate and frame and spiral-wound modules. Modules based on hollow fibre membranes are also considered, as well as the concept of multi-effect vacuum membrane distillation for improved heat recovery. The heat efficiency of each system is analysed based on available experimental results. Better internal heat recovery and capacity for upscaling are found to be important elements of distinction which make multi-channelled spiral-wound modules working in air-gap configuration stand out currently, with the lowest heat consumption of all large scale modules. Potential for improvement of this and other technologies is also discussed, and an estimation based on the associated costs for solar energy is used for establishing boundary conditions towards the implementation of membrane distillation for solar desalination

¿Hacia un sistema de metrópolis españolas policéntricas?: caracterización de su estructura metropolitana

Las metrópolis han sufrido en la última mitad de siglo un proceso de descentralización de la actividad económica y el desarrollo de nuevas centralidades fuera de sus cascos tradicionales. Este proceso, ha permitido la generación de subcentros de actividad, que captan actividad económica de los centros urbanos generando nuevos patrones de ocupación del territorio, que coexisten con los procesos de dispersión. En esta investigación, mediante el análisis de la densidad de empleo, se caracteriza la estructura policentrica de 7 áreas metropolitanas españolas: Madrid, Barcelona, Valencia, Bilbao, Sevilla, Zaragoza, y Málaga; en el sentido de identificar la forma en cómo la población y la actividad económica se distribuye en 4 tipos de asentamientos: 1) núcleos centrales de actividad, 2) continuos centrales, 3) núcleos satelitales de actividad, y 4) resto del área metropolitana. Los resultados sugieren que el nivel de policentrismo está asociado a dos factores: el tamaño de los sistemas metropolitanos y la matriz territorial en la que se ubican éstos; así, cuanto más grandes son los primeros y más accidentada es la segunda, el proceso de autoorganización espacial de la economía tiende a generar sistemas policéntricos.The cities have suffered in the last half century a process of decentralization of economic activity and development of new centralities outside their traditional helmets. This process has allowed the generation of sub-centers, that capture economic activity to generate new patterns in the territory, which coexist with the scattering processes. In this research, by analyzing the density of employment, polycentric structure characterized by seven metropolitan areas Spanish: Madrid, Barcelona, Valencia, Bilbao, Seville, Zaragoza, and Málaga, in the sense of identifying how and how people and economic activity is settled in into four types of settlement: 1) nuclei central activity, 2) Central continuous, 3) satellite nucleos , and 4) rest of the metropolitan area. The results suggest that the level of polycentrism is associated with two factors: the size of metropolitan system and the territorial matrix in which are located they, thus, the larger the first and most rugged is the second, the process of spatial self-organization of the economy tends to generate polycentric system.Peer Reviewe

Fachadas ligeras

Entre los temas objeto de estudio de la «Union Européenne pour l'agrément technique dans la construction», figura el genérico de «Fachadas ligeras». Los grupos de trabajo de la Asociación, integrados por técnicos especialistas, representan a los Centros de investigación de los diversos países europeos que la forman, donde se realizan los estudios y ensayos, eminentemente científicos y técnicos, los cuales son analizados en común en las llamadas Reuniones «ad-hoc» que vienen celebrándose desde hace unos años, como es sabido, en diferentes ciudades europeas

Control of quantum interference in the quantum eraser

We have implemented an optical quantum eraser with the aim of studying this phenomenon in the context of state discrimination. An interfering single photon is entangled with another one serving as a which-path marker. As a consequence, the visibility of the interference as well as the which-path information are constrained by the overlap (measured by the inner product) between the which-path marker states, which in a more general situation are non-orthogonal. In order to perform which-path or quantum eraser measurements while analyzing non-orthogonal states, we resort to a probabilistic method for the unambiguous modification of the inner product between the two states of the which-path marker in a discrimination-like process.Comment: Submitted to New Journal of Physics, March 200

The effect of pre-strain on fatigue for a high strength low alloy (HSLA) steel

The effect of initial plastic strain cycle fatigue lives of HSLA specimens is investigated. Specimens were monotonically, quasi-statically loaded under strain control in tension to produce plastic strains (prestrain conditions s0 = 0, s1 = 4,6, s2 = 35,6 and s3 = 66,7 % deformation). Surface analysis on the annealed Zn coat on the prestrain surfaces shows that, the higher the deformation the bigger and deeper the cracks on the Zn coat. Results show that the higher prestrain the higher fatigue resistance for all stress applied, specimens with s3 shows the highest fatigue resistance for these experimental conditions

Sustainable approach of high-pressure agave bagasse pretreatment for ethanol production

ABSTRACT: Agave bagasse is one of the most abundant lignocellulosic residues readily available for valorization. The agave bagasse was pretreated by applying high-pressure CO2–H2O mixture at temperatures ranging from 150 to 190 °C for a residence time varying from 10 to 50 min. Subsequently, solid phase obtained from pretreatment was subject to enzymatic hydrolysis at high solid loadings. Under optimal conditions, the process integrating pretreatment followed by enzymatic hydrolysis yielded 75.8 mol% of the polysaccharides present in the biomass converted into oligo- or monosaccharides, providing 110.5 g/L of reducing sugars. The monosaccharides present in the obtained hydrolysate were successfully fermented into ethanol, demonstrating the feasibility of performing its biological conversion to commercial biofuels or biochemicals. Thereby, the present study has demonstrated the proof of concept of use of more sustainable high-pressure CO2–H2O pretreatment in the context of lignocellulosic residual biomass valorization based on the biochemical sugar platform.info:eu-repo/semantics/publishedVersio