A Resource Extraction Model with Technology Adoption under Time Inconsistent Preferences

A two-stage non-standard optimal control problem with time inconsistent preferences is studied. In an infinite horizon setting, a time consistent (sophisticated) decision maker chooses the time of switching between two consecutive regimes. The second regime corresponds to the implementation of a new technology, and a cost must be paid at the switching time. Although the problem is formulated for a general discount function, special attention is devoted to models with nonconstant discounting and heterogeneous discounting. The problem is solved by transforming it into a problem in a finite horizon and free terminal time. The corresponding dynamic programming equations are presented, and conditions for the derivation of the switching time by decision makers with different degrees of sophistication are studied. A resource extraction model with technology adoption is solved in detail. Effects of the adoption of different discount functions are illustrated numerically

Los grupos GEI como experiencia docente orientada a estudiantes repetidores: el caso de Matemáticas I en Economía.

En este trabajo estudiamos las mejoras introducidas en los Grupos de Estudios de Intensificación (grupos GEI) durante el curso académico 2012-2013. La introducción de estos grupos ha sido una apuesta de la Facultat d"Economia i Empresa de la Universitat de Barcelona con el objetivo de facilitar al estudiante el seguimiento de las asignaturas que repite, teniendo en cuenta el perfil de este alumnado, y ofrecerle una vía atractiva que le facilite el seguimiento y superación de la materia, así como su compaginación con las otras asignaturas de primera matrícula. Tras un primer año de implantación en el curso académico 2011-2012, se redefinió el diseño de estos grupos con el objetivo de corregir las ineficiencias observadas. Estudiamos así, para la asignatura de Matemáticas I del grado de Economía, cómo estos cambios han incidido en el seguimiento y rendimiento, comparando los resultados con los obtenidos durante el pasado curso académico

Aprenentatge autònom de l'alumne i eines per al docent mitjançant l'ús de GeoGebra. Assignatures de Matemàtiques I i II dels Graus d’ADE i d’ECO de la Universitat de Barcelona

Línies d’innovació vinculades: 216231 - Moodle / 201995 - Avaluació formativa / 235623 - Project-based learning, PBL / 020691 - Estudi de casos / 025424 – SimulacionsL’objectiu del nostre projecte ha estat millorar la docència de les assignatures de Matemàtiques dels Graus d’Economia (ECO) i d’Administració i Direcció d’Empreses (ADE), introduint a la docència el software gratuït GeoGebra. El projecte va sorgir en el context de la implantació dels graus, en un moment en què vèiem que ja no podríem seguir fent les classes de pràctiques a les aules d’informàtica amb el programa Derive, que disposaríem de menys hores de docència i que a les aules només hi hauria un ordinador per al professor i un canó de projecció. En aquelles circumstàncies vam pensar que la capacitat de GeoGebra per donar vida a funcions i vectors podia ajudar-nos a explicar els conceptes teòrics de les assignatures de Matemàtiques d’una manera tan atractiva com intuïtiva. Hem elaborat un conjunt de materials (applets) per a les assignatures de Matemàtiques I i Matemàtiques II dels graus d’ADE i d’ECO. Gràcies a la plataforma Moodle hem pogut posar aquestes applets a disposició d’alumnes i professors

Student’s autonomous learning and tools for teachers by means of the use of GeoGebra. Mathematics I and II subjects of the degrees in ADE and ECO of the University of Barcelona

The objective of our project has been to improve the teaching in mathematics subjects of the degrees in Economics (ECO) and Business management (ADE) by incorporating the GeoGebra free software. The project started when university degrees were being implemented. At that time, we realized that we could no longer use the Derive software because the practical lectures in the computer rooms were cancelled and only the teacher's computer attached to a projector remained. On the top of that, the time devoted to lectures was reduced. Under those constraints, we thought that the ability of GeoGebra to give functions and vectors life could help us in explaining the theoretical concepts of the mathematics subjects in an appealing and intuitive manner. We have created several applets for the subjects Mathematics I and Mathematics II of the degrees in ECO and ADE. Thanks to the Moodle platform we have been able to put these applets at students’ and teachers’ disposal

Pre-multisymplectic constraint algorithm for field theories

We present a geometric algorithm for obtaining consistent solutions to systems of partial differential equations, mainly arising from singular covariant first-order classical field theories. This algorithm gives an intrinsic description of all the constraint submanifolds. The field equations are stated geometrically, either representing their solutions by integrable connections or, what is equivalent, by certain kinds of integrable m-vector fields. First, we consider the problem of finding connections or multivector fields solutions to the field equations in a general framework: a pre-multisymplectic fibre bundle (which will be identified with the first-order jet bundle and the multimomentum bundle when Lagrangian and Hamiltonian field theories are considered). Then, the problem is stated and solved in a linear context, and a pointwise application of the results leads to the algorithm for the general case. In a second step, the integrability of the solutions is also studied. Finally, the method is applied to Lagrangian and Hamiltonian field theories and, for the former, the problem of finding holonomic solutions is also analized.Comment: 30 pp. Presented in the International Workshop on Geometric Methods in Modern Physics (Firenze, April 2005

High dose chemotherapy and autologous stem cell transplantation in patients with peripheral T-cell lymphoma not achieving complete response after induction chemotherapy. The GEL-TAMO experience

Background and objectives: patients with aggressive non-Hodgkin's lymphomas (NHL) who do not obtain a complete response (CR) after induction chemotherapy have a poor prognosis. However, provided they are sensitive to the first regimen of chemotherapy, 25-40% of them with a B-cell phenotype may achieve long-term survival when treated with high dose chemotherapy and autologous stem cell transplantation (HDC/ASCT). The aim of this study was to analyze the efficacy of this therapy in the corresponding patients with peripheral T-cell lymphoma (PTCL). Design and methods: we retrospectively evaluated the efficacy of ASCT in 35 patients with PTCL from the GEL-TAMO registry, who did not achieve a CR to standard induction chemotherapy regimens for aggressive NHL. Thirty-one patients underwent transplantation after achieving a partial response (PR) and 4 patients were non-responders. Results: following HDC/ASCT, 23 (66%) of the patients achieved a CR, 4 (11%) a PR and in 7 (20%) cases the transplant failed. One patient was not evaluated because of early toxic death. With a median follow-up of the survivors of 37.5 months, 18 patients (51%) are alive and 15 patients (43%) are free of disease. Transplant-related mortality rate at 100 days was 11% and at 5 years the probabilities of survival, freedom from progression and disease-free survival for complete responders were 37%, 36% and 55% respectively. Pre-transplant lactate-dehydrogenase level, age-adjusted International Prognostic Index (aa-IPI) and tumor score correlated with survival. Interpretation and conclusions: one third of the patients with PTCL who fail to achieve CR to the first chemotherapeutic regimen can be rescued with HDC/ASCT. Pre-transplant values of IPI and tumor score risk systems for aggressive lymphomas were useful to predict subsequent survival

Aprendizaje autónomo del alumno y herramientas para el docente mediante el uso de GeoGebra. Asignaturas de Matemáticas I y II de los Grados de ADE y de ECO de la Universidad de Barcelona

El objetivo de nuestro proyecto ha sido mejorar la docencia de las asignaturas de Matemáticas de los Grados de Economía (ECO) y de Administración y Dirección de Empresas (ADE), introduciendo en la docencia el software gratuito GeoGebra. El proyecto surgió en el contexto de la implantación de los grados, en un momento en que veíamos que ya no podríamos seguir impartiendo las clases de prácticas en las aulas de informática con el programa Derive, que dispondríamos de menos horas de docencia y que en las aulas solo habría un ordenador para el profesor y un cañón de proyección. En aquellas circunstancias pensamos que la capacidad de GeoGebra para dar vida a funciones y vectores podía ayudarnos a explicar los conceptos teóricos de las asignaturas de Matemáticas de una manera tan atractiva como intuitiva. Hemos elaborado un conjunto de materiales (applets) para las asignaturas de Matemáticas I y Matemáticas II de los grados de ADE y de ECO. Gracias a la plataforma Moodle hemos podido poner estas applets a disposición de alumnos y profesores

J-PLUS: A first glimpse at spectrophotometry of asteroids -- The MOOJa catalog

Context: The Javalambre Photometric Local Universe Survey (J-PLUS) is an observational campaign that aims to obtain photometry in 12 ultraviolet-visible filters (0.3-1 {\mu}m) of approximately 8 500 deg{^2} of the sky observable from Javalambre (Teruel, Spain). Due to its characteristics and strategy of observation, this survey will let us analyze a great number of Solar System small bodies, with improved spectrophotometric resolution with respect to previous large-area photometric surveys in optical wavelengths. Aims: The main goal of this work is to present here the first catalog of magnitudes and colors of minor bodies of the Solar System compiled using the first data release (DR1) of the J-PLUS observational campaign: the Moving Objects Observed from Javalambre (MOOJa) catalog. Methods: Using the compiled photometric data we obtained very-low-resolution reflectance (photospectra) spectra of the asteroids. We first used a {\sigma}-clipping algorithm in order to remove outliers and clean the data. We then devised a method to select the optimal solar colors in the J-PLUS photometric system. These solar colors were computed using two different approaches: on one hand, we used different spectra of the Sun, convolved with the filter transmissions of the J-PLUS system, and on the other, we selected a group of solar-type stars in the J-PLUS DR1, according to their computed stellar parameters. Finally, we used the solar colors to obtain the reflectance spectra of the asteroids. Results: We present photometric data in the J-PLUS filters for a total of 3 122 minor bodies (3 666 before outlier removal), and we discuss the main issues of the data, as well as some guidelines to solve the

J-PLUS: Discovery and characterisation of ultracool dwarfs using Virtual Observatory tools

Ultracool dwarfs (UCDs) are objects with spectral types equal or later than M7. Most of them have been discovered using wide-field imaging surveys. The Virtual Observatory (VO) has proven to be of great utility to efficiently exploit these astronomical resources. We aim to validate a VO methodology designed to discover and characterize UCDs in the J-PLUS photometric survey. J-PLUS is a multiband survey carried out with the wide angle T80Cam optical camera mounted on the 0.83-m telescope JAST/T80 in the Observatorio Astrof\'isico de Javalambre. In this work we make use of the Internal Data Release (IDR) covering 528 deg$^2$. We complement J-PLUS photometry with other catalogues in the optical and IR using VOSA, a VO tool that estimates physical parameters from the spectral energy distribution fitting to collections of theoretical models. Objects identified as UCDs are distinguished from background M giants and highly reddened stars using parallaxes and proper motions from Gaia DR2. We identify 559 UCDs, ranging from i=16.2 to 22.4 mag, of which 187 are candidate UCDs not previously reported in the literature. This represents an increase in the number of known UCDs of about 50% in the studied region of the sky, particularly at the faint end of our sensitivity, which is interesting as reference for future wide and deep surveys such as Euclid. Three candidates constitute interesting targets for exoplanet surveys because of their proximity

J-PLUS:Searching for very metal-poor star candidates using the SPEEM pipeline

We explore the stellar content of the Javalambre Photometric Local Universe Survey (J-PLUS) Data Release 2 and show its potential to identify low-metallicity stars using the Stellar Parameters Estimation based on Ensemble Methods (SPEEM) pipeline. SPEEM is a tool to provide determinations of atmospheric parameters for stars and separate stellar sources from quasars, using the unique J-PLUS photometric system. The adoption of adequate selection criteria allows the identification of metal-poor star candidates suitable for spectroscopic follow-up. SPEEM consists of a series of machine learning models which uses a training sample observed by both J-PLUS and the SEGUE spectroscopic survey. The training sample has temperatures Teff between 4\,800 K and 9\,000 K; $\log g$ between 1.0 and 4.5, and $-3.