366 research outputs found

    Bosonization on a lattice: The emergence of the higher harmonics

    Get PDF
    6 págs.; 2 figs.A general and transparent procedure to bosonize fermions placed on a lattice is presented. Harmonics higher than kF in the one-particle Green function are shown to appear due to the compact character of real electron bands. Quantitative estimations of the role of higher harmonics are made possible by this bosonization technique. © 1995 The American Physical Society.J.F. was supported by DEYCIT Project No. PB93-1248.Peer Reviewe

    Augmented Reality as a Tool for Promoting the Tourist Value of the Geological Heritage Around Natural Filming Locations: a Case Study in “Sad Hill” (The Good, the Bad and the Ugly Movie, Burgos, Spain)

    Get PDF
    This research was funded by projects Junta Castilla y Leon SA044G18, University of Salamanca USAL2017/46AC01, and Spanish Ministry of Economy and Competitiveness CGL2015-69919-R.Some natural scenes of films shooting contain landscapes and other elements that are part of the geological heritage, representing an added value for the growing cultural tourism that visits them. In the SE of Burgos province (Spain), near some filming locations of the classic western movie directed by Sergio Leone (1966), “The Good, the Bad and the Ugly”, we have assessed the Geological Heritage of 6 selected sites: (1) Dinosaur tracks; (2) Paleo-river structures preserved; (3) Fossil trees; (4) Sad Hill; (5) Marine Cretaceous fossils; and (6) La Yecla Gorge. Their tourist-cultural, scientific and educational values range from 775 points in La Yecla Gorge site to 450 in Marine Cretaceous fossils site. A virtual tour is presented implementing Augmented Reality on Google Earth with detailed but easily understanding descriptive information of each site, suggested activities for tourism and a free geoapp. The proposed technologies can enhance geotourism, favouring sustainable development and fostering attitudes and skills related to the tourist’s respect for nature.publishersversionpublishe

    Algoritmo Genético aplicado al problema de programación en procesos tecnológicos de maquinado con ambiente Flow Shop

    Get PDF
    Debido a las limitaciones de las técnicas de optimización convencionales, en el siguiente trabajo se presenta una metaheurística basada en un algoritmo genético (AG), para resolver problemas de programación de tipo flow shop, con el objetivo de minimizar el tiempo de finalización de todos los trabajos, más conocido como makespan. Este problema, considerado de difícil solución, es típico de la optimización combinatoria y se presenta en talleres con tecnología de maquinado, donde existen máquinas-herramientas convencionales y se fabrican diferentes tipos de piezas que tienen en común una misma ruta tecnológica (orden del proceso). La solución propuesta se probó con problemas clásicos publicados por otros autores, obteniéndose resultados satisfactorios en cuanto a la calidad de las soluciones encontradas y el tiempo de cómputo empleado

    Depositional history of estuarine infill during the last postglacial transgression (Gulf of Cadiz, Southern Spain)

    Get PDF
    The Late Pleistocene and Holocene evolution of the estuaries in the Gulf of Cadiz is interpreted for the first time using drill cores, logs, trenches, and 38 new radiocarbon data, and the results compared with the shelf. The Odiel, Tinto and Guadalete Rivers deposited conglomerates during a highstand that did not reach the present sea level dated at ca. 25–30 ka (Isotopic Stage (IS) 3), corresponding to a relatively humid period in the area. Rivers incised these coarse-grained deposits during the last main lowstand at ca. 18 ka, when sea level dropped to -- 120 m and the coastline lay 14 km seawards from the present. The erosional surface is a sequence boundary and the flooding surface of the postglacial eustatic rise, overlain by the valley fill deposits of the transgressive and highstand phases of the last fourth- and fifth-order depositional sequences recognised in the shelf. The first marine influence in the estuaries during the transgression occurs at -25/-30 m at. ca. 10,000 years BP. According to fossil assemblages, the transgressed basins changed from brackish to more open marine as the sea rose until ca. 6500 years BP, when it reached the maximum flooding and the sandy estuarine barriers ceased to retrograde toward the muddy central basins. Then, the rate of eustatic rise decreased drastically, and the estuarine filling followed a two-fold pattern governed by the progressive change from vertical accretion to lateral (centripetal) progradation. At ca. 4000 years BP the fluvial input surpassed the already negligible rate of rise, causing partial emergence of tidal flats and spit barriers in the largely filled estuarine basins. Prevalence of coastal progradation upon vertical accretion at ca. 2400 years BP caused accelerated expansion of tidal flats and rapid growth of the sandy barriers. Further changes since the 16th century reflect widespread anthropic impacts. q2000 Elsevier Science B.V. All rights reserved

    La “Ruta de las huellas fósiles” (Monsagro, Salamanca): un ejemplo de iniciativa geoturística aplicada al desarrollo rural

    Get PDF
    Se presenta la “Ruta de las huellas fósiles”, realizada en el casco urbano de Monsagro (Sierra de Francia, Salamanca). Mediante seis paneles didácticos e interpretativos, que incluyen el acceso “online” desde las nuevas tecnologías (smartphone, tablets, ipod….) a información complementaria implementada en videos, códigos QR, geoapps y juegos, se han promocionado y divulgado los contenidos geológicos de la zona, basados principalmente en el interés paleontológico de sus icnofósiles, atribuidos a diversos tipos de gusanos y trilobites durante el Ordovícico Inferior, y en el interés geomorfológico de sus cresterías cuarcíticas con relieve apalachiense, del encajamiento fluvial del río Agadón y de sus formaciones superficiales como canchales. Los visitantes señalan como fortalezas de la ruta su fácil y didáctico recorrido, así como la implicación ciudadana en la conservación de las icnitas

    Preliminar paleontologic study from upper Tortonian deposits of «Las Pajanosas» (Sevilla, Guadalquivir Basin)

    Get PDF
    The paleontological record of a set of upper Tortonian outcrops nearby Las Pajanosas, north of Seville, has been studied. The most complete series of 15 metres of thickness, unconformed over upper Devonian metamorphic rocks, is divided in two sedimentary parts. 60 macrofaunal species have been identified. Bivalves group is the most abundant with 37 species, specially pectinids with 14 species. This outcrop presents the most diversity of pectinids in the Tortonian sections of the Guadalquivir Basin. The fossil content, distribution, taphonomy signature and sedimentological context, suggest a transgressive process over the paleorelief, with progressive deepening of the paleoenvironments in a global eustatic rising settin

    Bioactive compounds and techno-functional properties of high-fiber co-products of the cacao agro-industrial chain

    Get PDF
    The cacao shell (CS) and cacao pod husk (CPH), two of the most promising high-fiber co-products of the cacao agro-industrial chain, were evaluated to determine their potential incorporation into food products. This research determined bioactive compounds and techno-functional properties of CS and CPH, and was evaluated the enzymatic inactivation by thermal treatments in CPH. We found that CS is rich in protein, lipids, dietary fiber (48.1 ± 0.3 g 100 gdw−1), and antioxidant molecules such as epicatechin (1.10 ± 0.02 mg g−1) and isoquercetin (1.04 ± 0.09 mg g−1). Moreover, in CS a positive effect of hydration mechanism occur; in fact, it was observed a reduction of Lightness (L∗) value and a remarkable color difference (ΔE∗,18.8 ± 0.7) (CIEL∗a∗b∗ color space), between hydrated and dry CS samples; so, it could be used as a potential natural colorant in foods. CPH resulted equally rich in dietary fiber (35.3–37.4%) and flavonoids (2.9 ± 0.1 mg RE g−1); in this co-product, the rapid enzymatic inactivation by thermal treatments was essential to obtain the highest antioxidant activity and polyphenols content; regarding the techno-functional properties, it was found that CPH flour had high hydration capacity, so CPH can use it as a replacement for emulsifiers or water holding additives while incorporating the fiber and abundantly found antioxidants

    The angiopoietin-like protein 4, apolipoprotein C3, and lipoprotein lipase axis is disrupted in patients with rheumatoid arthritis

    Get PDF
    Background: Modulators of triglyceride metabolism include lipoprotein lipase (LPL), angiopoietin-like protein 4 (ANGPTL4), and apolipoprotein C-3 (ApoC3). There is evidence on the influence of this triangle of molecules on an increased risk of atherosclerotic cardiovascular disease (CV) in the general population. Patients with rheumatoid arthritis (RA) present changes in lipid profiles and accelerated CV disease. In the present study, we set out to study whether the ANGPTL4, ApoC3, and LPL axis differs in subjects with RA compared to controls. In a further step, we investigated the relationship of this axis with subclinical atherosclerosis in patients with RA. Methods: Cross-sectional study that included 569 individuals, 323 patients with RA and 246 age-matched controls. ANGPTL4, ApoC3 and LPL, and standard lipid profiles were analyzed in patients and controls. Carotid intima-media thickness (cIMT) and carotid plaques were assessed in RA patients. A multivariable analysis was performed to assess whether the ANGPTL4, ApoC3, and LPL axis was altered in RA and to study its relationship with RA dyslipidemia and subclinical carotid atherosclerosis. Results: Most lipid profile molecules did not differ between patients and controls. Despite this, and after fully multivariable analysis including CV risk factors, use of statins, and changes in the lipid profile caused by the disease itself, patients with RA showed higher serum levels of ANGPTL4 (beta coef. 295 [95% CI 213-376] ng/ml, p<0.001) and ApoC3 (beta coef. 2.9 [95% CI 1.7-4.0] mg/dl, p<0.001), but lower circulating LPL (beta coef. -174 [95% CI -213 to - 135] ng/ml, p<0.001). ANGPTL4 serum levels were positively and independently associated with a higher cIMT in patients with RA after fully multivariable adjustment. Conclusion: The axis consisting in ANGPTL4, ApoC3, and LPL is disrupted in patients with RA. ANGPTL4 serum levels are positively and independently associated with a higher cIMT in RA patients.Funding: This work was supported by a grant to IFA from the Spanish Ministry of Health, Subdirección General de Evaluación y Fomento de la Investigación, Plan Estatal de Investigación Científica y Técnica y de Innovación 2013-2016 and by Fondo Europeo de Desarrollo Regional - FEDER - (Fondo de Investigaciones Sanitarias, PI17/00083)
    corecore