As dificultades de incorporación das mulleres matemáticas á universidade

[RESUMO] Votamos una ollada as primeiras mulleres matemáticas no eido universitario en Europa dende finais do século XIX, analizamos tamén a situación actual en datos porcentuais facendo especial fincapé nas mulleres españolas e nas galegas. Destacamos as singularidades dalgunhas mulleres que nun ámbito desfavorable sobresaíron polos seus logros académicos e/ou científicos

Perverse coherent t-structures through torsion theories

Bezrukavnikov (later together with Arinkin) recovered the work of Deligne defining perverse $t$-structures for the derived category of coherent sheaves on a projective variety. In this text we prove that these $t$-structures can be obtained through tilting torsion theories as in the work of Happel, Reiten and Smal\o. This approach proves to be slightly more general as it allows us to define, in the quasi-coherent setting, similar perverse $t$-structures for certain noncommutative projective planes.Comment: New revised version with important correction

Resolving Sets Tolerant to Failures in Three-Dimensional Grids

[Abstract] An ordered set S of vertices of a graph G is a resolving set for G if every vertex is uniquely determined by its vector of distances to the vertices in S. The metric dimension of G is the minimum cardinality of a resolving set. In this paper we study resolving sets tolerant to several failures in three-dimensional grids. Concretely, we seek for minimum cardinality sets that are resolving after removing any k vertices from the set. This is equivalent to finding (k+1)-resolving sets, a generalization of resolving sets, where, for every pair of vertices, the vector of distances to the vertices of the set differs in at least k+1 coordinates. This problem is also related with the study of the (k+1)-metric dimension of a graph, defined as the minimum cardinality of a (k+1)-resolving set. In this work, we first prove that the metric dimension of a three-dimensional grid is 3 and establish some properties involving resolving sets in these graphs. Secondly, we determine the values of k≥1 for which there exists a (k+1)-resolving set and construct such a resolving set of minimum cardinality in almost all cases.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sk lodowska-Curie grant agreement No 734922. M. Mora is supported by projects H2020-MSCA-RISE-2016-734922 CONNECT, PID2019-104129GB-I00/MCIN/AEI/10.13039/501100011033 of the Spanish Ministry of Science and Innovation and Gen.Cat. DGR2017SGR1336; M. J. Souto-Salorio is supported by project PID2020-113230RB-C21 of the Spanish Ministry of Science and Innovation. Open Access funding provided thanks to the CRUECSIC agreement with Springer NatureGeneralitat de Catalunya; DGR2017SGR133

Resolving Sets Tolerant to Failures in Three-Dimensional Grids

[Abstract] An ordered set S of vertices of a graph G is a resolving set for G if every vertex is uniquely determined by its vector of distances to the vertices in S. The metric dimension of G is the minimum cardinality of a resolving set. In this paper we study resolving sets tolerant to several failures in three-dimensional grids. Concretely, we seek for minimum cardinality sets that are resolving after removing any k vertices from the set. This is equivalent to finding (k+1)-resolving sets, a generalization of resolving sets, where, for every pair of vertices, the vector of distances to the vertices of the set differs in at least k+1 coordinates. This problem is also related with the study of the (k+1)-metric dimension of a graph, defined as the minimum cardinality of a (k+1)-resolving set. In this work, we first prove that the metric dimension of a three-dimensional grid is 3 and establish some properties involving resolving sets in these graphs. Secondly, we determine the values of k≥1 for which there exists a (k+1)-resolving set and construct such a resolving set of minimum cardinality in almost all cases.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sk lodowska-Curie grant agreement No 734922. M. Mora is supported by projects H2020-MSCA-RISE-2016-734922 CONNECT, PID2019-104129GB-I00/MCIN/AEI/10.13039/501100011033 of the Spanish Ministry of Science and Innovation and Gen.Cat. DGR2017SGR1336; M. J. Souto-Salorio is supported by project PID2020-113230RB-C21 of the Spanish Ministry of Science and Innovation. Open Access funding provided thanks to the CRUECSIC agreement with Springer NatureGeneralitat de Catalunya; DGR2017SGR133

Ion counting efficiencies at the IGISOL facility

At the IGISOL-JYFLTRAP facility, fission mass yields can be studied at high precision. Fission fragments from a U target are passing through a Ni foil and entering a gas filled chamber. The collected fragments are guided through a mass separator to a Penning trap where their masses are identified. This simulation work focuses on how different fission fragment properties (mass, charge and energy) affect the stopping efficiency in the gas cell. In addition, different experimental parameters are varied (e. g. U and Ni thickness and He gas pressure) to study their impact on the stopping efficiency. The simulations were performed using the Geant4 package and the SRIM code. The main results suggest a small variation in the stopping efficiency as a function of mass, charge and kinetic energy. It is predicted that heavy fragments are stopped about 9% less efficiently than the light fragments. However it was found that the properties of the U, Ni and the He gas influences this behavior. Hence it could be possible to optimize the efficiency.Comment: 52 pages, 44 figure

Algorithms for determining relative position between spheroids and hyperboloids with one sheet

©2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https:// creativecommons.org/licenses/by-nc-nd/4.0/. This version of the article: Castro, P. M., Dapena, A., Souto- Salorio, M. J., & Tarrío-Tobar, A. D. (2019). 'Algorithms for determining relative position between spheroids and hyperboloids with one sheet', has been accepted for publication in Mathematics and Computers in Simulation, 160, 168–179.The Version of Record is available online at https://doi.org/10.1016/j.matcom.2018.12.006.[Abstract]: In this work we present a new method for determining relative positions between one moving object, modelled by a bounding spheroid, and surrounding static objects, modelled by circular hyperboloids of one sheet. The proposed strategy is based on the real-time calculation of the coefficients of degree three polynomial. We propose several algorithms for two real applications of this geometric problem: the first one, oriented to the design of video games, and the second one, devoted to surveillance tasks of a quadcopter in industrial or commercial environments.This work has been funded by the Xunta de Galicia, Spain (ED431C 2016-045, ED341D R2016/012, ED431G/01), the Agencia Estatal de Investigación of Spain (TEC2013-47141-C4-1-R, TEC2015-69648-REDC, TEC2016-75067-C4-1-R) and ERDF funds of the EU (AEI/FEDER, UE). The authors wish to thank José Sanmartín for his helpful work in the graphic design of the pictures included in this paper.Xunta de Galicia; ED431C 2016-045Xunta de Galicia; ED341D R2016/012Xunta de Galicia; ED431G/0