63 research outputs found

    Uhlmann phase as a topological measure for one-dimensional fermion systems

    Get PDF
    We introduce the Uhlmann geometric phase as a tool to characterize symmetry-protected topological phases in one-dimensional fermion systems, such as topological insulators and superconductors. Since this phase is formulated for general mixed quantum states, it provides a way to extend topological properties to finite temperature situations. We illustrate these ideas with some paradigmatic models and find that there exists a critical temperature Tc at which the Uhlmann phase goes discontinuously and abruptly to zero. This stands as a borderline between two different topological phases as a function of the temperature. Furthermore, at small temperatures we recover the usual notion of topological phase in fermion systems

    Modeling the external flow of a novel HorseShoe receiver and the evaluation of thermal performance

    Get PDF
    The linear receiver of a Parabolic Trough Collector is the most critical element in the entire system. The Universal Vacuum Air Collector concept is the most extended type of receiver in both experimental and industrial facilities. Besides their considerable cost, their efficiency usually drops as operation time passes. This is mainly due to a partial loss of vacuum in the evacuated annulus between the absorber and the glass cover. An alternative design called HorseShoe receiver is proposed in this work, whose main goal is to maintain the thermal performance throughout its entire lifespan. This innovative receiver is indicated for low-to-medium temperature ranges, which is particularly suitable for solar heat for industrial processes. It consists of a horseshoe-like cavity absorber having its upper border insulated. In addition, two main advantages can be taken by using two symmetric lenses as glass cover: reconcentrate solar radiation into the cavity (improvement of the intercept factor) and protect stratification conditions (reduction of thermal losses). A transient numerical model with customized boundary conditions has been implemented to evaluate both thermal performance and temperature difference in the absorber domain, which is critical for the thermal stress conditions. For that purpose and as a key contribution, not only the Heat Transfer Fluid (HTF) temperature but also the heat transfer coefficient in the duct are set. In particular, HTF temperature ranges from 80 °C to 220 °C and the inner heat transfer coefficient from 600 W/(mK) to 1800 W/(mK). Results show that numerical thermal performance is above 96%, which is mainly due to the reduction of thermal radiation losses, where the absorber active surface emittance is . (...)Second (corresponding) author J.J. Serrano-Aguilera acknowledges the support provided by Junta de Andalucía (Government of Andalusia) and Universidad de Málaga for the source of funding for the HERTERSOL project (UMA18-FEDERJA-195), as well as to Ministerio de Ciencia, Innovación Universidades (Spain) by means of the postdoc position: Ref No. FJCI-2017-32403 (Juan de la Cierva-Formación Postdoc Grant). Third author acknowledges the support of Universidad de Málaga, Spain through the Project WALICON, 2021. Authors also acknowledge funding for open access charge: Universidad de Málaga / CBUA

    Evolución de la innovación educativa en la Universidad Complutense: proyecto UNICOMEX

    Get PDF
    La evolución de la educación universitaria en España ha experimentado una enorme evolución en los últimos veinte años. Desde la enseñanza centrada en la clase magistral, con el consiguiente protagonismo del profesor, a lo que sucede actualmente, con el estudiante como eje principal, media todo un cambio en el planteamiento de nuestro sistema educativo universitario. La implantación del Espacio Europeo de Educación Superior (EEES) ha sido uno de los objetivos perseguidos por la Universidad Complutense de Madrid (UCM) en la última década. Con este fin existieron, hasta hace poco, las conocidas como Asignaturas Piloto (AP) e igualmente se convocan periódicamente, desde hace años, los Proyectos de Innovación Educativa (P.I.E.). Ambas herramientas han procurado facilitar dicha adaptación, así como promover un concepto transversal en la transmisión del conocimiento. Nuestro grupo de trabajo puede ser un ejemplo de lo que la UCM ha querido conseguir con ambas cosas. La asignatura ha participado en todas las convocatorias de AP, pasando por una evolución clara desde la clase magistral a los pequeños grupos de trabajo. Ha sido, además, el instrumento útil para ir desarrollando distintos P.I.E., hasta un total de nueve, tras formar un equipo interdisciplinar constituido por profesores universitarios y profesionales de diversos ámbitos. El último de estos PIE, concedido en el curso académico 2011-2012, consiste en la creación de un espacio virtual de referencia para el estudio de los animales exóticos, partiendo de los resultados obtenidos en proyectos anteriores. UNICOMEX (Universidad-Complutense-Exóticos) nace con el objetivo de poner al alcance de cualquiera una serie de recursos virtuales ordenados que faciliten el conocimiento biológico, anatómico y clínico de los animales exóticos, entendiendo como tales aquellos que, siendo de interés veterinario, no se consideran domésticos. La totalidad de su contenido está en español e inglés, con el fin de hacer de ella una herramienta virtual útil y abierta a la comunidad científica y didáctica internacional

    La medicina rural: una visión mirando al futuro

    Get PDF
    The management of any large building stock with limited resources poses a problem of prioritization of refurbishment actions. Also, available technical information about the building stock is often incomplete and the process of standardization and updating is expensive and time consuming. Some public owners are developing preliminary BIM models of their stock, but they are willing to limit the complexity of the models within the lowest amount of information required for management and maintenance, so as to make that process affordable. Indeed, administrations are challenged by their duty relative to planning regular maintenance and operation of buildings, because of the legislation in force, which requires monitoring of their facilities. For the reasons stated above, this paper presents a decision support tool that can help prioritize refurbishment actions on large building assets. To this purpose, many requirements must be jointly considered in this examination, each requirement being assessed by means of one or several indicators. Then the indicators are compared one another, according to a multi-criteria approach, that weighs the several criteria and rank the assets. In order to deal with the extensive and uncertain information that must be managed in this process, indicators are estimated by means of Bayesian Networks. This tool is used first to assess the technical indicators and rank the assets, while marking any facilities not complying with regulations. Then, additional Bayesian Networks are in charge of estimating the budget needed to upgrade non-compliant facilities with minimum legislation requirements. The outcomes of this research can be used even to assess the level of detail of the information that must be included in BIM models of the stock, in fact acting as guidelines for their development. Finally, the application of the decision tool on a real test case will be presented

    Nitrogen and Phosphorous Retention in Tropical Eutrophic Reservoirs with Water Level Fluctuations: A Case Study Using Mass Balances on a Long-Term Series

    Get PDF
    Nitrogen and phosphorous loading drives eutrophication of aquatic systems. Lakes and reservoirs are often effective N and P sinks, but the variability of their biogeochemical dynamics is still poorly documented, particularly in tropical systems. To contribute to the extending of information on tropical reservoirs and to increase the insight on the factors affecting N and P cycling in aquatic ecosystems, we here report on a long-term N and P mass balance (2003–2018) in Valle de Bravo, Mexico, which showed that this tropical eutrophic reservoir lake acts as a net sink of N (−41.7 g N m y) and P (−2.7 g P m y), mainly occurring through net sedimentation, equivalent to 181% and 68% of their respective loading (23.0 g N m y and 4.2 g P m y). The N mass balance also showed that the Valle de Bravo reservoir has a high net N atmospheric influx (31.6 g N m y), which was 1.3 times the external load and likely dominated by N fixation. P flux was driven mainly by external load, while in the case of N, net fixation also contributed. During a period of high water level fluctuations, the net N atmospheric flux decreased by 50% compared to high level years. Our results outlining water regulation can be used as a useful management tool of water bodies, by decreasing anoxic conditions and net atmospheric fluxes, either through decreasing nitrogen fixation and/or promoting denitrification and other microbial processes that alleviate the N load. These findings also sustain the usefulness of long-term mass balances to assess biogeochemical dynamics and its variability.This research was funded by UNAM, PAPIIT-IN207702 and CONACYT-SEMARNAT, C01-1125 projects to M.M-

    An Experimental DUAL Model of Advanced Liver Damage

    Get PDF
    Individuals exhibiting an intermediate alcohol drinking pattern in conjunction with signs of metabolic risk present clinical features of both alcohol-associated and metabolic-associated fatty liver diseases. However, such combination remains an unexplored area of great interest, given the increasing number of patients affected. In the present study, we aimed to develop a preclinical DUAL (alcohol-associated liver disease plus metabolic-associated fatty liver disease) model in mice. C57BL/6 mice received 10% vol/vol alcohol in sweetened drinking water in combination with a Western diet for 10, 23, and 52 weeks (DUAL model). Animals fed with DUAL diet elicited a significant increase in body mass index accompanied by a pronounced hypertrophy of adipocytes, hypercholesterolemia, and hyperglycemia. Significant liver damage was characterized by elevated plasma alanine aminotransferase and lactate dehydrogenase levels, extensive hepatomegaly, hepatocyte enlargement, ballooning, steatosis, hepatic cell death, and compensatory proliferation. Notably, DUAL animals developed lobular inflammation and advanced hepatic fibrosis. Sequentially, bridging cirrhotic changes were frequently observed after 12 months. Bulk RNA-sequencing analysis indicated that dysregulated molecular pathways in DUAL mice were similar to those of patients with steatohepatitis. Conclusion: Our DUAL model is characterized by obesity, glucose intolerance, liver damage, prominent steatohepatitis and fibrosis, as well as inflammation and fibrosis in white adipose tissue. Altogether, the DUAL model mimics all histological, metabolic, and transcriptomic gene signatures of human advanced steatohepatitis, and therefore serves as a preclinical tool for the development of therapeutic targets.Supported by EXOHEP-CM (S2017/BMD-3727), Ramón y Cajal (RYC-2014-15242 and RYC-2015-17438), NanoLiver-CM (Y2018/NMT-4949), COST Action (CA17112), AMMF (2018/117), ERAB (EA 18/14), MINECO Retos (SAF2016-78711 and SAF2017-87919-R), and German Research Foundation (DFG NE 2128/2-1, SFB 1382-403224013/A02, and SFB/TRR57/P04). FJC is a Gilead Research Liver Scholar. The research group belongs to the validated Research group Ref. 970935 “Liver Pathophysiology”, 920631 “Lymphocyte immunology”, 920361 “Immunogenética e inmunología de las mucosas” and IBL-6 (imas12-associated). FG and KZ are Chinese Scholarship Council (CSC) fellows. O.E.-V is supported by Beca FPI (associated to MINECO SAF2017-87919R) and R.B.-U. by Contratos predoctorales de personal investigador en formación UCM-Banco Santander (CT63/19)

    Geographic genetic structure of Iberian columbines (gen. Aquilegia)

    Get PDF
    Southern European columbines (genus Aquilegia)are involved in active processes of diversification, and the Iberian Peninsula offers a privileged observatory to witness the process. Studies on Iberian columbines have provided significant advances on species diversification,but we still lack a complete perspective of the genetic diversification in the Iberian scenario. This work explores how genetic diversity of the genus Aquilegia is geographically structured across the Iberian Peninsula. We used Bayesian clustering methods, principal coordinates analyses, and NJ phenograms to assess the genetic relationships among 285 individuals from 62 locations and detect the main lineages. Genetic diversity of Iberian columbines consists of five geographically structured lineages, corresponding to different Iberian taxa. Differentiation among lineages shows particularly complex admixture patterns at Northeast and highly homogeneous toward Northwest and Southeast. This geographic genetic structure suggests the existence of incomplete lineage sorting and interspecific hybridization as could be expected in recent processes of diversification under the influence of quaternary postglacial migrations. This scenario is consistent with what is proposed by the most recent studies on European and Iberian columbines, which point to geographic isolation and divergent selection by habitat specialization as the main diversification drivers of the Iberian Aquilegia complex

    COVIDiSTRESS Global Survey dataset on psychological and behavioural consequences of the COVID-19 outbreak

    Full text link
    This N = 173,426 social science dataset was collected through the collaborative COVIDiSTRESS Global Survey – an open science effort to improve understanding of the human experiences of the 2020 COVID-19 pandemic between 30th March and 30th May, 2020. The dataset allows a cross-cultural study of psychological and behavioural responses to the Coronavirus pandemic and associated government measures like cancellation of public functions and stay at home orders implemented in many countries. The dataset contains demographic background variables as well as measures of Asian Disease Problem, perceived stress (PSS-10), availability of social provisions (SPS-10), trust in various authorities, trust in governmental measures to contain the virus (OECD trust), personality traits (BFF-15), information behaviours, agreement with the level of government intervention, and compliance with preventive measures, along with a rich pool of exploratory variables and written experiences. A global consortium from 39 countries and regions worked together to build and translate a survey with variables of shared interests, and recruited participants in 47 languages and dialects. Raw plus cleaned data and dynamic visualizations are available

    Los contratos sobre el buque en Derecho Español. Análisis práctico

    Get PDF
    Prólogo / José Luis Gabaldón García (pp. 9-13). -- Introducción (pp. 15-18). -- El contrato de construcción naval: aspectos prácticos / Gonzalo Alvar Ezquerra (pp. 19-37). -- El contrato de compraventa / Carlos López-Quiroga, Luz Martínez de Azcoitia y José Sánchez-Fayos Martín-Peña (pp. 39-58). -- El contrato de arrendamiento de buque / Rodolfo González Lebrero (pp. 59-75). -- El contrato de fletamento por tiempo / José María Alcántara González (pp. 77-102). -- El contrato de fletamento por viaje: contenido obligacional / Juan Pablo Rodríguez Delgado (pp. 103-144). -- El contrato de transporte marítimo en régimen de conocimiento de embarque / Javier del Corte (pp. 145-186). -- Los documentos de transporte / Carlos Llorente (pp. 187-205). -- Contratos de utilización del buque para fines distintos del transporte de mercancías / José Manuel G. Pellicer (pp. 207-221). -- El contrato de arrendamiento náutico / León von Ondarza (pp. 223-244). -- El contrato de pasaje marítimo / Hannah de Bustos, Antonio Quirós de Sas y Julio López Quiroga (pp. 245-260). -- Los contratos de gestión naval para la dotación del buque / Bernardo Ruiz Lima (pp. 261-279). -- El contrato de gestión naval / Víctor Mata Garrido (pp. 281-302). -- El contrato de consignación de buques /Jesús Barbadillo Eyzaguirre (pp. 303-323). -- El contrato de manipulación portuaria / Carlos Pérez (pp. 325-338). -- El contrato de practicaje / Alicia Velasco Nates (pp. 339-356). -- Los contratos de mediación en la explotación del buque / Carmen Codes Cid y Martín Prieto Sulleiro (pp. 357-372). -- El contrato de remolque / Ana Sánchez Horneros (pp. 373- 392). -- El contrato de remolque / Jaime de Castro (pp. 393-412). -- El contrato de salvamento / Luis Souto (pp. 413-430). -- El contrato de remoción de restos / Verónica Meana (pp. 431-446). -- El contrato de clasificación del buque / Jaime Rodrigo de Larrucea (pp. 447-463). -- El seguro de casco y máquina / Carlos Cerdá Donat y Diego de San Simón Palacios (pp. 465-491). -- Los clubes de protección e indemnización (P&I) / Miguel Caballero (pp. 493-504). -- El seguro de protección e indemnización (P&I) / Jaime Albors (pp. 505-524). -- El seguro del acreedor hipotecario / Luis F. Gómez de Mariaca Fernández (pp. 525-540)

    Effectiveness of an intervention for improving drug prescription in primary care patients with multimorbidity and polypharmacy:Study protocol of a cluster randomized clinical trial (Multi-PAP project)

    Get PDF
    This study was funded by the Fondo de Investigaciones Sanitarias ISCIII (Grant Numbers PI15/00276, PI15/00572, PI15/00996), REDISSEC (Project Numbers RD12/0001/0012, RD16/0001/0005), and the European Regional Development Fund ("A way to build Europe").Background: Multimorbidity is associated with negative effects both on people's health and on healthcare systems. A key problem linked to multimorbidity is polypharmacy, which in turn is associated with increased risk of partly preventable adverse effects, including mortality. The Ariadne principles describe a model of care based on a thorough assessment of diseases, treatments (and potential interactions), clinical status, context and preferences of patients with multimorbidity, with the aim of prioritizing and sharing realistic treatment goals that guide an individualized management. The aim of this study is to evaluate the effectiveness of a complex intervention that implements the Ariadne principles in a population of young-old patients with multimorbidity and polypharmacy. The intervention seeks to improve the appropriateness of prescribing in primary care (PC), as measured by the medication appropriateness index (MAI) score at 6 and 12months, as compared with usual care. Methods/Design: Design:pragmatic cluster randomized clinical trial. Unit of randomization: family physician (FP). Unit of analysis: patient. Scope: PC health centres in three autonomous communities: Aragon, Madrid, and Andalusia (Spain). Population: patients aged 65-74years with multimorbidity (≥3 chronic diseases) and polypharmacy (≥5 drugs prescribed in ≥3months). Sample size: n=400 (200 per study arm). Intervention: complex intervention based on the implementation of the Ariadne principles with two components: (1) FP training and (2) FP-patient interview. Outcomes: MAI score, health services use, quality of life (Euroqol 5D-5L), pharmacotherapy and adherence to treatment (Morisky-Green, Haynes-Sackett), and clinical and socio-demographic variables. Statistical analysis: primary outcome is the difference in MAI score between T0 and T1 and corresponding 95% confidence interval. Adjustment for confounding factors will be performed by multilevel analysis. All analyses will be carried out in accordance with the intention-to-treat principle. Discussion: It is essential to provide evidence concerning interventions on PC patients with polypharmacy and multimorbidity, conducted in the context of routine clinical practice, and involving young-old patients with significant potential for preventing negative health outcomes. Trial registration: Clinicaltrials.gov, NCT02866799Publisher PDFPeer reviewe
    corecore