QUANTUM COMPUTING AND HPC TECHNIQUES FOR SOLVING MICRORHEOLOGY AND DIMENSIONALITY REDUCTION PROBLEMS

Tesis doctoral en período de exposición públicaDoctorado en Informática (RD99/11)(8908

Electronic structure and experimental benchmarking of aluminum spinels for solar water splitting

A computational methodology for screening aluminum-based spinel oxides for photoelectrochemical water splitting has been developed by combining HSE06 and PBE + U calculations. The method, which can be extended to other ternary oxides, provides values for formation energies, band gaps, band edge positions, and carrier effective masses. The formation energies indicate that the Al spinels of Mg, Co, Ni, and Zn (successfully synthesized using a sol-gel method) are among the most stable in the series. Except for the Mg and Zn cases, the electronic structures of the spinels are rather similar, with band gaps separating occupied and empty 3 d metal states. The charge-transfer band gap values are found to be above 3 eV, limiting the use of these materials in solar water splitting, although an estimate of the band edge positions indicates that, in general, both conduction band electrons and valence band holes can promote water reduction and oxidation, respectively. The effective masses of the charge carriers suggests that the spinels are n-type semiconductors as experimentally demonstrated. Importantly, both the UV–vis spectra and the photoelectrochemical results qualitatively agree with the theoretical electronic structure. In general vein, this work demonstrates the potential of theoretical screening for the development and selection of new photoelectrode materials based on ternary oxides for their application in solar water splitting.The authors gratefully acknowledge funding from the European Union’s Horizon 2020 research and innovation program under grant agreement no. 760930 (FotoH2 project). This research was also partially funded by the Ministerio de Ciencia e Innovación/Agencia Estatal de Investigación/Fondos FEDER through project PID2021-128876OB-I00 and by the Generalitat Valenciana through project PROMETEO/2020/089. F.J.P. also acknowledges the Spanish Ministry of Education for the award of an FPU grant

External validation of a prognostic model based on total tumor load of sentinel lymph node for early breast cancer patients

Background: A prognostic model based on the results of molecular analysis of sentinel lymph nodes (SLN) is needed to replace the information that staging the entire axilla provided. The aim of the study is to conduct an external validation of a previously developed model for the prediction of 5-year DFS in a group of breast cancer patients that had undergone SLN biopsy assessed by the One Step Nucleic Acid Amplification (OSNA) method. Methods: We collected retrospective data of 889 patients with breast cancer, who had not received systemic treatment before surgery, and who underwent SLN biopsy and evaluation of all SLN by OSNA. The discrimination ability of the model was assessed by the area under the ROC curve (AUC ROC), and its calibration by comparing 5-years DFS Kaplan–Meier estimates in quartile groups of model predicted probabilities (MPP). Results: The AUC ROC ranged from 0.78 (at 2 years) to 0.73 (at 5 years) in the training set, and from 0.78 to 0.71, respectively, in the validation set. The MPP allowed to distinguish four groups of patients with heterogeneous DFS (log-rank test p < 0.0001). In the highest risk group, the HR were 6.04 [95% CI 2.70, 13.48] in the training set and 4.79 [2.310, 9.93] in the validation set. Conclusions: The model for the prediction of 5-year DFS was successfully validated using the most stringent form of validation, in centers different from those involved in the development of the model. The external validation of the model confirms its utility for the prediction of 5-year DFS and the usefulness of the TTL value as a prognostic variable.This study was supported by Sysmex España S.L

Clinical presentation of acute coronary syndrome in patients previously treated with nitrates

Aims: Several reports have suggested that nitrates limit acute ischaemic damage by a mechanism similar to preconditioning. This study aims to evaluate the effect of chronic oral nitrates on the clinical presentation and short-term outcomes of patients admitted with acute coronary syndrome (ACS).Methods: A retrospective cohort study was conducted in patients with ACS admitted to 62 acute care units from 2010 to 2011. A propensity score-matched samples analysis was performed.Results: We analysed 3171 consecutive patients, of whom 298 (9.4%) were chronically treated with nitrates. Patients previously treated with nitrates had higher comorbidity and disease severity at admission, lower prevalence of ACS with ST elevation, lower troponin elevation, higher prevalence of initial Killip class 2-4 and higher hospital mortality. The propensity score-matched analysis confirmed that previous use of nitrates is independently associated with a lower prevalence of ST-elevation ACS [odds ratio (OR) 0.53, 95% confidence interval (CI) 0.36-0.78; P = 0.0014] and a lower troponin elevation (OR 0.61, 95% CI 0.41-0.92) but not with Killip class on admission (OR 1.18, 95% CI 0.83-1.67, P = 0.3697) or mortality (OR 0.71, 95% CI 0.37-1.38, P = 0.3196).Conclusion: The results support the hypothesis that nitrates have a protective effect on acute ischaemic injury

Nuevo método de evaluación mediante revisiones cruzadas de los estudiantes

Actualmente nos enfrentamos a nuevos desafíos en el mundo de la educación. Entre las cuestiones más importantes se encuentra el grado de participación y compromiso de los estudiantes en su propio proceso de aprendizaje y esto implica que deban participar en su evaluación de manera activa. Así, en este artículo se presenta un nuevo método de evaluación empleado en la asignatura “Arquitecturas y Sistemas Operativos para Tiempo Real”, del título de Ingeniería Informática de la Universidad de Alicante. En este novedoso método, los alumnos participan en el proceso de evaluación de sus propios trabajos por medio de revisiones cruzadas (peer-reviewing) que pretenden identificar las carencias o errores en los trabajos presentados por sus compañeros de asignatura. En pocas semanas los estudiantes pueden entender la innovadora visión del proceso de enseñanza-aprendizaje empleado en nuestra asignatura y se involucran activamente en dicho proceso; con todo ello, sus conocimientos han de actualizarse de manera continua, por lo que son capaces de entender y asimilar los nuevos conceptos explicados por el profesor

Desarrollo de una unidad didáctica sobre circuitos y sistemas reversibles para la asignatura de Tecnología Industrial II

Aunque el desarrollo de la tecnología relativa a los circuitos y sistemas lógicos están en continuo avance durante las últimas décadas, las bases de dicha tecnología apenas han cambiado durante este tiempo, como puede verse fácilmente al comparar un libro de sistemas digitales de hace 20 años con uno actual. Sin embargo, el auge de nuevas tecnologías reversibles, motivado por causas tan dispares como el ahorro energético -con la vista puesta en el preocupante cambio climático- o el creciente interés de la computación cuántica, amenaza por primera vez este statu quo. De no educar a nuestros estudiantes teniendo en cuenta esta nueva tendencia, corremos el riesgo de que se instauren nuevas tecnologías para las que no se dispone de personal cualificado. En este trabajo, se motiva la necesidad de comenzar a incluir formación especializada en estas nuevas tecnologías, presentando un ejemplo funcional de unidad didáctica sobre circuitos y sistemas reversibles para la asignatura de Tecnología Industrial II de 2º de Bachillerato. La unidad didáctica ha sido realizada poniendo en práctica todos los conocimientos adquiridos en el Máster de Secundaria de la Universidad de Almería. Abstract: The development of digital circuits and systems has advanced steadily over the past decades. Nevertheless, the bases of such technology have hardly changed during this time, as can be easily seen by comparing a 20-year-old book on digital systems with a current one. The rise of new reversible technologies, motivated by causes as diverse as energysaving - with an eye on the worrying climate change - or the growing interest in quantum computing, threatens this status quo for the first time. If we do not educate our students in these technologies, we will not have qualified personnel to work with them in the future. In this work, the need for including specialized training in these new technologies is motivated, presenting a functional example of a didactic unit on reversible circuits and systems for the subject of Industrial Technology II. The didactic unit has been carried out by putting into practice the knowledge acquired in the Master's Degree in Secondary at the University of Almería

Diseño optimizado de un circuito comparador para computación cuántica

This work presents a comparator circuit for quantum computing. The circuit is able to determine, given two bit strings A and B of any length, whether A is less than or equal to B, or whether A is greater than B. Although there are already other comparators for quantum computing, the circuit proposed in this work allows this operation to be performed with a smaller number of qubits. Qubits are the minimum unit of information in quantum computing. As current quantum devices have a very limited number of qubits, achieving circuits that optimize their use is crucial for this computing paradigm. Typically, each qubit that is successfully reduced from a circuit design allows extending the length of the strings that the circuit can compare by one unit, which can also translate as an increase in data size by an order of magnitude in base 2. But achieving such optimization is not trivial, as quantum circuits have important restrictions such as the impossibility of copying values or the requirement that the computation done in them must always be reversible.En este trabajo se presenta un circuito comparador para computación cuántica. El circuito es capaz de determinar, dadas dos cadenas de bits A y B de cualquier longitud, si A es menor o igual a B, o bien si A es mayor que B. Aunque ya existen otros comparadores para computación cuántica, el circuito que se propone en este trabajo permite realizar dicha operación necesitando un menor número de cúbits. Los cúbits son la unidad mínima de información en computación cuántica. Como los dispositivos cuánticos actuales disponen de una cantidad muy limitada de cúbits, conseguir circuitos que optimicen su uso es crucial para este paradigma de computación. Típicamente, cada cúbit que se logra reducir del diseño de un circuito permite extender la longitud de las cadenas que el circuito puede comparar en una unidad, lo que también puede traducirse como un aumento del tamaño de los datos en un orden de magnitud en base 2. Pero lograr tal optimización no resulta trivial, pues los circuitos cuánticos tienen restricciones importantes tales como la imposibilidad de copiar valores o la exigencia de que la computación que en ellos se hace siempre debe ser reversibl

Photoelectrochemical Behavior and Computational Insights for Pristine and Doped NdFeO3 Thin-Film Photocathodes

Among the different strategies that are being developed to solve the current energy challenge, harvesting energy directly from sunlight through a tandem photoelectrochemical cell (water splitting) is most attractive. Its implementation requires the development of stable and efficient photocathodes, NdFeO3 being a suitable candidate among ternary oxides. In this study, transparent NdFeO3 thin-film photocathodes have been successfully prepared by a citric acid-based sol–gel procedure, followed by thermal treatment in air at 640 °C. These electrodes show photocurrents for both the hydrogen evolution and oxygen reduction reactions. Doping with Mg2+ and Zn2+ has been observed to significantly enhance the photoelectrocatalytic performance of NdFeO3 toward oxygen reduction. Magnesium is slightly more efficient as a dopant than Zn, leading to a multiplication of the photocurrent by a factor of 4–5 for a doping level of 5 at % (with respect to iron atoms). This same trend is observed for hydrogen evolution. The beneficial effect of doping is primarily attributed to an increase in the density and a change in the nature of the majority charge carriers. DFT calculations help to rationalize the behavior of NdFeO3 by pointing to the importance of nanostructuring and doping. All in all, NdFeO3 has the potential to be used as a photocathode in photoelectrochemical applications, although efforts should be directed to limit surface recombination.This work has been developed in the context of project RTI2018-102061-B-I00 financed by FEDER/Ministerio de Ciencia e Innovación-Agencia Estatal de Investigación. The Generalitat Valenciana through project PROMETEO/2020/089 is also gratefully acknowledged. J.Q. and F.J.P. thank the Ministerio de Educación, Cultura y Deporte (MECD) for the award of FPU predoctoral grants (FPU15/02005 and FPU16/02492, respectively)

Stoichiometry control and phosphorus doping as strategies for the enhancement of nickel iron spinel oxides as electrocatalysts for water oxidation

Energy storage and conversion may depend on the development of (photo)electrochemical devices relying on water oxidation. Finding electrode materials based on earth abundant elements is critical in this respect. Multinary transition metal oxides, such as the iron group spinels, can be efficient water oxidation electrocatalysts in alkaline media. Both Ni-rich and Fe-rich nickel ferrites have been synthesized through a chemical bath method by selecting specific bath temperature and composition. These electrodes, constituted by nanosheets, have been modified by the incorporation of phosphorus (as phosphate) in the structure, leading to either a substantial decrease (of around 0.1 V) in the overvoltage for oxygen evolution or a drastic decrease in the Tafel slope. Phosphate seems to have a dual role: it stabilizes the high oxidation states of surface nickel and probably provides sites for fast proton transfer. Both factors are needed for an efficient oxygen evolution reaction.This work has been financially supported by the Spanish Ministry of Science, Innovation and Universities under project RTI2018e102061eBeI00 (FONDOS FEDER). FJP also acknowledges the Spanish Ministry of Education for the award of an FPU grant

Análisis del proceso de enseñanza-aprendizaje a través de herramientas de comunicación síncrona y asíncrona: caso de la asignatura de Química Física Aplicada

El presente trabajo presenta un análisis de las ventajas e inconvenientes de las herramientas de comunicación docente-discente síncronas y asíncronas. Tomando como referencia la asignatura de Química Física Aplicada se ha evaluado: (i) la adecuación de la docencia síncrona / asíncrona; (ii) el efecto de las diferentes herramientas en los resultados del aprendizaje; (iii) el interés del alumnado en función de la metodología; y (iv) el impacto de la metodología empleada en la interacción con el profesorado. La investigación obedece a un estudio mixto en el que se combinan métodos cualitativos y cuantitativos y para la que ha sido necesario diseñar actividades formativas tanto asíncronas como síncronas. La percepción del alumnado se ha obtenido mediante la realización de encuestas online de carácter no obligatorio. Para este estudio, también se han considerado otros indicadores objetivos como la asistencia a las clases síncronas, número de visualizaciones y descargas, número de tutorías recibidas y su carácter síncrono o asíncrono. Los resultados obtenidos muestran las ventajas e inconvenientes de la docencia no presencial síncrona y asíncrona, tanto desde la perspectiva del profesorado, como desde la del alumnado. Mientras que la docencia síncrona o dual favorece la comunicación docente-discente, la docencia asíncrona favorece la independencia del alumnado y la gestión del tiempo. Esta es probablemente la principal razón por la que el alumnado prefiere claramente la docencia asíncrona.Esta investigación se ha llevado a cabo con el apoyo del Programa de Redes-I3CE de investigación en docencia universitaria del Instituto de Ciencias de la Educación de la Universidad de Alicante (convocatoria 2020-21) (Ref.:5252)