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[EN] In this communication we present an interview with Dr. Eduardo Sáenz de Cabezón, professor, researcher and scientific disseminator in the area of Mathematics. The interview was carried out to celebrate the international Pi day of the year 2021. This event belonged to the periodic cycle of joint activities Math & Beyond UPV organized by the Department of Applied Mathematics, the University Institute of Multidisciplinary Mathematics and the University Institute of Pure and Applied Mathematics, all from the Universitat Politècnica de València. In the conversation we spoke with Professor Sáenz de Cabezón about education and mathematical dissemination, and we were able to know first-hand his opinion on various current issues. The full interview can be accessed via https://www.youtube.com/watch?v=ztMe6eSbp4I&feature=youtu.be, [ES] En esta comunicación presentamos una entrevista realizada al Dr. Eduardo Sáenz de Cabezón, profesor, investigador y divulgador científico en el área de las Matemáticas. La entrevista se realizó con motivo de la celebración del día internacional de Pi del año 2021, dentro del ciclo periódico de actividades conjuntas Math & Beyond UPV organizada por el Departamento de Matemática Aplicada, el Instituto Universitario de Matematica Multidisciplinar y el Instituto Universitario de Matemática Pura y Aplicada de la Universitat Politècnica de València. En la conversación hablamos con el profesor Sáenz de Cabezón sobre educación y divulgación matemática, y pudimos conocer de primera mano su opinión sobre diversos temas de actualidad. A la entrevista completa se puede acceder a través del enlace: https://www.youtube.com/watch?v=ztMe6eSbp4I&feature=youtu.be, A Eduardo Sáenz de Cabezón por permitirnos hacer y transcribir su entrevista. Al Departamento de Matemática Aplicada, el Instituto Universitario de Matemática Pura y Aplicada, y el Instituto Universitario de Matemática Multidisciplinar por co-organizar y patrocinar el evento. Especialmente, a los profesores Jose Manuel Calabuig Rodríguez, Alberto Conejero Casares, Juan Carlos Cortés López, Lluís M. García Raffi y Antonio Hervás Jorge, por el apoyo y la ayuda en la organización.

[EN] Biological systems are commonly constituted by a high number of interacting agents. This great dimensionality hinders biological modelling due to the high computational cost. Therefore, new modelling methods are needed to reduce computation time while preserving the properties of the depicted systems. At this point, Boolean Networks have been revealed as a modelling tool with high expressiveness and reduced computing times. The aim of this work has been to introduce an automatic and coherent procedure to model systems through Boolean Networks. A synergy that harnesses the strengths of both approaches is obtained by combining an existing approach to managing information from biological pathways with the so-called Nested Canalising Boolean Functions (NCBF). In order to show the power of the developed method, two examples of an application with systems studied in the bibliography are provided: The epithelial-mesenchymal transition and the lac operon. Due to the fact that this method relies on directed graphs as a primary representation of the systems, its applications exceed life sciences into areas such as traffic management or machine learning, in which these graphs are the main expression of the systems handled., This paper has been supported by the Generalitat Valenciana grant AICO/2020/114

[EN] A methodology to model a process in which repeated events occur is presented. The context is the evolution of non-muscle-invasive bladder carcinoma (NMIBC), characterized by recurrent relapses. It is based on the statistical flowgraph approach, a technique specifically suited for semi-Markov processes. A very useful feature of the flowgraph framework is that it naturally incorporates the management of censored data. However, this approach presents two difficulties with the process to be modeled. On one hand, the management of covariates is not straightforward. However, it is of great interest to know how the characteristics of a certain patient influence the evolution of the disease. On the other hand, repeated events on the same subject are generally not independent, in which case the semi-Markov framework is not sufficient because the semi-Markov assumption implies independence among waiting time distributions. We solve this issue by extending the flowgraph methodology using the Markovian arrival process (MAP), which does successfully model the dependence between events. Along the way, we provide a procedure to consider covariates and censored times in MAPs, a pending task needed in this field. In short, we have managed to extend the flowgraph methodology beyond the semi-Markovian framework, simplifying the incorporation of covariates and keeping the management of censored times. All of which has allowed us to build a multistate model of the evolution of NMIBC. The developed model allows us to compute the Survival function for any evolution of a patient with specific clinic-pathological characteristics in this primary tumor.

Objective:Overactive bladder is a disease with a high prevalence. The management is difficult, because different demographic, social or economic aspects converge. Our objective was to evaluate the efficacy and satisfaction in patients with overactive bladder treated with transcutaneous electrostimulation of the posterior tibial nerve.Methods:This was a prospective and descriptive study of 45 patients with overactive bladder (with or without detrusor overactivity) resistant to pharmacological treatment. Patients received a weekly session for 12 weeks, with a duration of 30 minutes for each of the sessions. There was a screening after 12 sessions, after which if there had been no response, treatment was suspended and maintenance sessions were not continued (six twice-monthly sessions and three monthly sessions). It was considered that the treatment had been effective when it was possible to decrease the number of events, except the maximum voiding volume, the objective of which was to increase. The results were evaluated using a 3-day voiding diary, an overactive bladder short form questionnaire and a satisfaction level questionnaire. Statistical analysis was performed using IBM SPSS Statistics version 19.0. Independent variables with a normal distribution were examined using the t-test. The Wilcoxon signed-rank test was used to compare the averages of the quantitative variables without a normal distribution. Satisfaction was analysed by a binary and ordinal regression analysis, univariate and multivariate. A P value less than 0.05 was considered statistically significant.Results:All the parameters of the study improved to a statistically relevant degree: frequency, nocturia, urgency, maximum voided volume, urge urinary incontinence. The overactive bladder short form questionnaire score improved but was not statistically significant.Conclusions:The use of transcutaneous electrostimulation of the posterior tibial nerve is a safe, effective and minimally invasive alternative in the treatment of overactive bladder when pharmacological treatment has failed. Patients had a good objective and subjective response in our study.Level of evidence:4.

Statistical Flowgraph Models are an efficient tool to model multi-state stochastic processes. They support both frequentist and Bayesian approaches. Inclusion of covariates is also available. In this paper we propose an easy way to perform a Bayesian approach with covariates. Results are presented with an application to bladder carcinoma data. (C) 2015 Elsevier B.V. All rights reserved.

[EN] Purpose The purpose of this paper is to evaluate the contribution of location (geographical concentration) and firm structure (age and subsector) to the risk of business failure. Design/methodology/approach The Markov s regression analysis was made for a sample of over 11,700 Spanish textile-clothing firms. Findings The results obtained from the analysis suggest that the risk of business failure is increased by some risk factors relative to the structural characteristics of the firms (younger firms and specialization in low-tech activities), and under determined locational circumstances. Research limitations/implications Our conclusions have been obtained starting from a sample of manufacturing firms in the Spanish textile sector. An extension of this work would be to test its robustness in other countries (for example, Italy or Portugal) and/or for other industries such as footwear and furniture. Practical implications Explaining the different levels of risk business failure shown by firms in an industry. Originality/value Work that has studied the failure of the textile firms within this location- subsector relationship is still scarce. Given that the viability of clusters and of European textile have been put into question, our work evidences that the risk of failure related to the firm s location and structure needs to be tested jointly, so that the way in which the firm addresses environmental changes can be appraised., This investigation was supported by the Research Project GV2011-025 of the Generalitat Valenciana (Spain).

Multiple sequential recurrences are one of the most important characteristics of superficial transitional cell carcinoma of the bladder, more than 50% of the patients will have recurrences (reappearance of a new superficial tumor). When in the same subject recurrent events are considered and these observed events are clustered into groups, independence between the clustered survival times cannot be assumed. A natural way to model the dependence of clustered event times is through the introduction of a cluster-specific random effect: the frailty term. On the other hand, between 10% and 30% of patients diagnosed with bladder carcinoma will present a muscle invasive progression, so the observation process of recurrences could be interrupted by a major failure event (progression). In this regard, a joint modelling of the two processes could make the study of a joint evolution over time possible, giving unbiased and efficient parameters. We jointly analyze recurrences and progression processes by means of the joint frailty model.

The aim of this study is to analyze survival until extirpation in bladder carcinoma. For this it is necessary to study the different stages of this chronic disease: multiple recurrences and progression. The sum of two random independent variables is considered, each of them being associated with a homogeneous time-continuous Markovian process of multiple absorbing states. The distribution function of the variable sum is modeled by means of a new associated Markov process. In order to maintain manageable problem dimension we have applied the Frechet derivate and the Kronecker matrix representation.

The risk of a new tumor recurrence after transurethral resection (surgical operation) in patients with primary superficial bladder carcinoma is evaluated. As the exact time of the event is not known, it is suggested to consider interval-censored survival data methodology. We use the model of Farrington to perform a prognostic model for predicting a new recurrence and to determine the clinicopathologic factors associated within interval-censored data framework. The implementation of this method is easy using standard statistical packages. Anyway, we use diagnostic methods for the validation of the model developed by the same author for interval-censored data. The obtained model is easily interpretable and let us to individualize the course of follow-up and treatment of each patient in order to improve the patient�s quality of life.

[EN] Current methodologies involve personal and group intervention by students leading to consider new approaches in the evaluation methods maintaining the relationship with the learning objectives that must cover the subjects of the degree courses. We intend to show an innovation made in the form of oral presentations evaluating the group work in the course of Computational Mathematics Laboratory of the first year in the Degree of Electronic Engineering and Automation. This evaluation will consider both the teacher's qualification as those made by each of the group members. It is desirable this cooperative attitude and responsibility of all team members and convey the message that each of them is responsible for work done both against their partners as to the teacher. The evaluation method used is presented in detail and also the results obtained. Subsequently, the opinion of the students about this change in the evaluation of group work will be exhibited., [ES] Las metodologías actuales implican una intervención personal y grupal por parte de los alumnos lo que lleva a considerar nuevos enfoques en los métodos de evaluación manteniendo la relación con los objetivos de aprendizaje que deben cubrir las asignaturas de las titulaciones de grado. Se pretende mostrar una innovación realizada en la forma de evaluar las presentaciones orales de los trabajos realizados en grupo en la asignatura de Laboratorio de Matemática Computacional de primer curso en la titulación de Grado en Ingeniería Electrónica y Automática. En esta evaluación se consideran tanto la calificación del profesor como las aportadas por cada uno de los miembros del grupo. Se pretende reforzar la actitud de colaboración y responsabilidad de todos los miembros del equipo y transmitir el mensaje de que cada uno de ellos es responsable del trabajo realizado tanto frente a sus compañeros como ante el profesor. Se presentará detalladamente el método de evaluación utilizado. Posteriormente se expondrá la opinión de los alumnos sobre este cambio en la evaluación de los trabajos en grupo., Projecte d’Innovació Docent en el Departamento de Matemática Aplicada de la Universitat Politècnica de València (PID-DMA 2014).

[EN] In reliability, sometimes some failures are not observed at the exact moment of the occurrence. In that case it can be more convenient to approximate them by a time interval. In this study, we have used a generalized non-linear model developed for interval-censored data to treat the life time of a pipe from its time of installation until its failure. The aim of this analysis was to identify those network characteristics that may affect the risk of failure and we make an exhaustive validation of this analysis. The results indicated that certain characteristics of the network negatively affected the risk of failure of the pipe: an increase in the length and pressure of the pipes, a small diameter, some materials used in the manufacture of pipes and the traffic on the street where the pipes are located. Once the model has been correctly fitted to our data, we also provided simple tables that will allow companies to easily calculate the pipe's probability of failure in a future., The research by A. Debón was supported by the Ministerio de Ciencia e Innovación of Spain under grant no. MTM2013-45381-P

Using a representative sample of Spanish individuals, we explore the effects of workers’ education on self‐assessed satisfaction with diverse specific aspects of their jobs. We find that the effects of education level on job satisfaction differ, both in size and direction, according to the aspect of the job considered, especially after controlling for actual job attributes and other workers’ characteristics. We also find that workers’ perceptions of the match between education and employment are relevant as determinants of job satisfaction irrespective of workers’ education level.

Background: Superficial bladder cancer has been the subject of numerous studies for many years, but the evolution of the disease still remains not well understood. After the tumor has been surgically removed, it may reappear at a similar level of malignancy or progress to a higher level. The process may be reasonably modeled by means of a Markov process. However, in order to more completely model the evolution of the disease, this approach is insufficient. The semi-Markov framework allows a more realistic approach, but calculations become frequently intractable. In this context, flowgraph models provide an efficient approach to successfully manage the evolution of superficial bladder carcinoma. Our aim is to test this methodology in this particular case. Results: We have built a successful model for a simple but representative case. Conclusion: The flowgraph approach is suitable for modeling of superficial bladder cancer.

[EN] This paper deals with the analytic-numerical solution of random heat problems for the temperature distribution in a semi-infinite bar with different boundary value conditions. We apply a random Fourier sine and cosine transform mean square approach. Random operational mean square calculus is developed for the introduced transforms. Using previous results about random ordinary differential equations, a closed form solution stochastic process is firstly obtained. Then, expectation and variance are computed. Illustrative numerical examples are included., This work has been partially supported by the Ministerio de Economia y Competitividad Grant no. DPI2010-20891-C02-01 and Universitat Politecnica de Valencia Grant no. PAID06-11-2070.