Solvable scalar and spin models with near-neighbors interactions

We construct new solvable rational and trigonometric spin models with near-neighbors interactions by an extension of the Dunkl operator formalism. In the trigonometric case we obtain a finite number of energy levels in the center of mass frame, while the rational models are shown to possess an equally spaced infinite algebraic spectrum. For the trigonometric and one of the rational models, the corresponding eigenfunctions are explicitly computed. We also study the scalar reductions of the models, some of which had already appeared in the literature, and compute their algebraic eigenfunctions in closed form. In the rational cases, for which only partial results were available, we give concise expressions of the eigenfunctions in terms of generalized Laguerre and Jacobi polynomials

Waste and Recycled Materials and their Impact on the Mechanical Properties of Construction Composite Materials

In a world increasingly fixated on the demands of sustainable development, too much attention has been focused on the widely used building materials, mainly on those tools and strategies for their reuse and those characteristics for considering them as environmental-friendly materials. Among the strategies are the following: (a) increased reliability on waste and recycled materials—such action will have to incorporate the substitution of recycled for virgin materials; (b) improved durability through reduction of materials needed for their replacement; and (c) improved mechanical properties, which reduces the use of raw materials. Extensive research and development activities in recycling composite materials have been conducted, and various technologies have been developed: (a) mechanical recycling, (b) thermal recycling, and (c) chemical recycling. However, gamma radiation is an innovative and clean technology, alternative to conventional recycling procedures. Gamma irradiation has proved to be an adequate tool for modifications of the physicochemical properties of polymers, through different effects: (a) scission, branching as well as cross-linking of polymer chains and (b) oxidative degradation. Moreover, the reuse and recycling of waste materials and the use of gamma radiation are useful tools for improving the mechanical properties of concrete. In this chapter, we show results of the effects of gamma irradiation on the physicochemical properties of waste and recycled materials and their reuse to enhance the properties of construction composite materials

Reflux patterns and risk factors of primary varicose veins clinical severity

Producción CientíficaAbstract Objectives: Primarily, to determine the association between the clinical severity of primary varicose veins and different reflux patterns in an anatomic and haemodynamic clinical study using duplex ultrasonography (DU). Secondly, to analyse the association of clinical severity with other aspects, such as risk factors for chronic venous insufficiency (CVI) and other concurrent diseases. Method: A total of 2036 limbs were evaluated using DU. Clinical status was characterized by the CEAP (clinical, aetiological, anatomical and pathological elements) classification. The degree of clinical severity was grouped into two categories, mild to moderate CVI (C1–C3) and severe CVI, characterized by the presence of skin changes (C4–C6). We analysed the association of the different reflux patterns with CEAP status. Results: Saphenofemoral junction (SFJ) reflux of the great saphenous vein (GSV) was associated with the most severe form of the disease (odds ratio [OR] ¼ 2.96; confidence interval [CI] 95%: 2.2–3.8), whereas competent SFJ of the GSV with reflux from proximal veins (OR ¼ 2; CI 95%: 1.4–2.7) and the pure non-saphenous reflux (OR ¼ 4.1; CI 95%: 1.8–9.0) were associated with mild to moderate CVI. Obesity increased the frequency of severe CVI 2.7 times (OR ¼ 2.7; CI 95%: 1.6–4.6); being a woman also increased the frequency of more severe disease 1.3 times (OR ¼ 1.3; CI 95%: 1.0–1.7). Conclusion: Anatomical and haemodynamic studies by DU are postulated as a useful diagnostic tool that allow, by identifying the pattern of venous reflux of varicose pathology, characterization of the probable association to CVI clinical severity

Control of dissipation in superconducting films by magnetic stray fields

Hybrid superconducting/magnetic nanostructures on Si substrates have been built with identical physical dimensions but different magnetic configurations. By constructing arrays based on Co-dots with in-plane, out-of-plane, and vortex state magnetic configurations, the stray fields are systematically tuned. Dissipation in the mixed state of superconductors can be decreased (increased) by several orders of magnitude by decreasing (increasing) the stray magnetic fields. Furthermore, ordering of the stray fields over the entire array helps to suppress dissipation and enhance commensurability effects increasing the number of dissipation minima

Fisheries interactions of Delphinus delphis in the north-east Atlantic with an emphasis on Galicia, north-west Spain.

Bycatch from interactions with fisherie s remains the biggest global threat to marine mammals. Galicia, north - west Spain, is one of the world’s main fishing regions and a high level of cetacean - fisheries interactions has been reported from on - board observers, interviews with fisheries stakeholde rs and analysis of stranded and by - caught carcasses. Delphinus delphis is the most abundant cetacean in the area and since 1990 necropsies of over 1800 stranded and by - caught Delphinus have been conducted. Life history data (age, maturity, and pregnancy ra te data) from stranded and by - caught cetaceans can be used to construct life tables and to estimate overall mortality and fisheries mortality rates. Age and maturity were determined from stranded and by - caught Delphinus between 1990 and 2009. Males and fem ales reach sexual maturity at 8.5 and 7.5 years of age, respectively, and no temporal difference in age at sexual maturity was observed. Results indicate 13% annual mortality in the Delphinus delphis north - east Atlantic population and necropsy data suggest s that 60% of mortality (i.e. 7.2% annual mortality) is attributable to fisheries interactions, predominantly from pair trawls and gillnets. By - caught Delphinus were found to die significantly younger than non - by - caught animals (p=<0.001) although no sex - r elated difference in bycatch rate was observed (p=0.051). The estimated annual mortality due to fisheries interactions greatly exceeds the 2% limit set by ASCOBANS and the IWC and high bycatch rates are also reported for other countries e.g. the UK, France and Portugal. Although Delphinus delphis in the north - east Atlantic is one continuous population, the high level of bycatch occurring in parts of the range is most likely unsustainable and will be discussed. There is a need to carry out on - board monitorin g, notably in the north - west Iberian Peninsula (Galicia and Portugal), to incorporate cetacean bycatch into fisheries advice and, above all, to start introducing mitigation measures

Electrical activity of crystal defects in multicrystalline Si

Producción CientíficaUpgraded metallurgical-grade silicon solar cells with different ranges of efficiencies have been characterized by light-beam-induced current (LBIC) measurements. The interaction between grain boundaries and metallic impurities is studied for cells fabricated on wafers from different solidification heights of the ingot. A tight relation is observed between the electrical activity of the grain boundaries and the position of the wafer in the ingot, which is related to the impurity contamination. The presence of a large amount of metallic impurities enhances the electrical activity of the grain boundaries. The main features of the LBIC images are discussed in relation to the presence of metallic impurities.Junta de Castilla y León (project VA283P18)Ministerio de Economía, Industria y Competitividad (project ENE2017-89561-C4-3-R

Defect recognition by means of light and electron probe techniques for the characterization of mc-Si wafers and solar cells

Producción CientíficaMulticristalline Silicon (mc-Si) is the preferred material for current terrestrial photovoltaic applications. However, the high density of defects present in mc-Si deteriorates the material properties, in particular the minority carrier diffusion length. For this reason, a large effort to characterize the mc-Si material is demanded, aiming to visualize the defective areas and to quantify the type of defects, density and its origin. In this work, several complementary light and electron probe techniques are used for the analysis of both mc-Si wafers and solar cells. These techniques comprise both fast and whole-area detection techniques such as Photoluminescence imaging, and highly spatially resolved time consuming techniques, such as light and electron beam induced current techniques and μRaman spectroscopy. These techniques were applied to the characterization of different mc-Si wafers for solar cells, e.g. ribbon wafers, cast mc-Si as well as quasi-monocrystalline material, upgraded metallurgical mc-Si wafers, and finished solar cells.Junta de Castilla y León (programa de apoyo a proyectos de investigación - Ref. VA166A11-2)Ministerio de Ciencia e Innovación (Proyect IPT-420000-2010-022 INNPACTO)Ministerio de Economía, Industria y Competitividad (Project ENE2014-56069-C4-4-R

Association of Human Leukocyte Antigens Class II Variants with Susceptibility to Hidradenitis Suppurativa in a Caucasian Spanish Population

Hidradenitis suppurativa (HS) is a chronic inflammatory cutaneous disease of the hair follicle typically presenting recurrent, painful, and inflamed lesions on the inverse areas of the body. Although its pathogenesis remains unknown, the immune system appears to play a potential role. To date, two previous studies have not found any association between the Human Leukocyte Antigen system (HLA) and HS. In this study we analyzed the HLA-A, -B, -C; and DRB1, -DQA1, and ?DQB1 allele distribution in 106 HS patients and 262 healthy controls from a Caucasian population in Cantabria (northern Spain). HLA-A*29 and B*50 were significantly more common in HS patients and A*30 and B*37 in controls, but these associations disappeared after statistical correction. DRB1*07, DQA1*02, and DQB1*02 were significantly more common in controls (p 0.026, p 0.0012, and p 0.0005, respectively) and the HLA allele DQB1*03:01 was significantly more common in HS patients (p 0.00007) after the Bonferroni correction. The DRB1*07~DQA1*02~DQB1*02 haplotype was significantly more common in controls (p < 0.0005). This is the first study showing an association between HLA-class II and HS. Our results suggest that HLA-II alleles (DRB1*07, DQA1*02, DQB1*02, and DQB1*03:01) and the DRB1*07~DQA1*02~DQB1*02 haplotype could influence resistance or susceptibility to HS