Sílvia Cañellas i Martínez, J. Perez de la Paz, Isabel Noguer, Fernando Villaamil Pérez, M. L. García Berrocal, Luís de la Fuente, MJ Belza, Jesús Castilla,
To analyze high-risk sexual behavior as regards HIV, the use of preventive measures and the patient-reported prevalence of HIV infections among males belonging to one of the leading homosexual associations in the Region of Madrid.Cross-sectional study conducted in 1997-1998 by way of mailed anonymous questionnaires. An analysis is made of the sociodemographic characteristics, how often condoms are used for different types of sexual intercourse with regular or casual partners, patient-reported prevalence ...
Tópico(s): Sex work and related issues
2000 - Ministry of Health of Spain | Revista Española de Salud Pública
María Isabel Jociles Rubio, Ana María Rivas Rivas, Beatriz Moncó, Fernando Villaamil Pérez,
En este artículo se analizan los discursos sobre las motivaciones que las Madres Solteras por Elección (MSPE) aducen para optar, o no, por las diferentes vías de acceso a la monoparentalidad electiva que ellas mismas distinguen: la que denominan “el engaño”, esto es, la fecundación sexual planificada pero no declarada, la fecundación sexual mediante “donante conocido”, la fecundación asistida y la adopción internacional. Estos discursos, producidos tanto en entrevistas cualitativas como en otros contextos ...
Tópico(s): LGBTQ Health, Identity, and Policy
2010 - Antropólogos Iberoamericanos en Red | AIBR Revista de Antropologia Iberoamericana
María Isabel Jociles Rubio, Fernando Villaamil Pérez,
Se analiza el discurso sobre las motivaciones que las Madres Solteras por Elección (MSPE) madrileñas aducen para optar o no por la fecundación sexual como vía de acceso a la maternidad.Este discurso, producido en entrevistas cualitativas y en otros contextos de interacción que han sido objeto de observación participante, revela que las MSPE distinguen dos formas de construir sus familias mediante la fecundación sexual: una es "el engaño" (mantener relaciones orientadas subrepticiamente al embarazo) ...
Tópico(s): Family Dynamics and Relationships
2012 - University of Tarapacá | Chungara
Felix Reidl, Peter Rossmanith, Fernando Sánchez Villaamil, Somnath Sikdar,
The width measure treedepth, also known as vertex ranking, centered coloring and elimination tree height, is a well-established notion which has recently seen a resurgence of interest. We present an algorithm which—given as input an n-vertex graph, a tree decomposition of width w, and an integer t—decides whether the input graph has treedepth at most t in time 2 O(wt) ·n. We use this to construct further algorithms which do not require a tree decomposition as part of their input: A simple algorithm ...
Tópico(s): Limits and Structures in Graph Theory
2014 - Springer Science+Business Media | Lecture notes in computer science
Jakub Gajarský, Petr Hliněný, Jan Óbdržálek, Sebastian Ordyniak, Felix Reidl, Peter Rossmanith, Fernando Sánchez Villaamil, Somnath Sikdar,
Meta-theorems for polynomial (linear) kernels have been the subject of intensive research in parameterized complexity. Heretofore, there were meta-theorems for linear kernels on graphs of bounded genus, H-minor-free graphs, and H-topological-minor-free graphs. To the best of our knowledge, there are no known meta-theorems for kernels for any of the larger sparse graph classes: graphs of bounded expansion, locally bounded expansion, and nowhere dense graphs. In this paper we prove meta-theorems for ...
Tópico(s): Graph Labeling and Dimension Problems
2013 - Springer Science+Business Media | Lecture notes in computer science
Aaron Adcock, Erik D. Demaine, Martin L. Demaine, Michael P. O’Brien, Felix Reidl, Fernando Sánchez Villaamil, Blair D. Sullivan,
When can t terminal pairs in an m × n grid be connected by t vertex-disjoint paths that cover all vertices of the grid? We prove that this problem is NP-complete. Our hardness result can be compared to two previous NP-hardness proofs: Lynch's 1975 proof without the “cover all vertices” constraint, and Kotsuma and Takenaga's 2010 proof when the paths are restricted to have the fewest possible corners within their homotopy class. The latter restriction is a common form of the famous Nikoli puzzle Numberlink. ...
Tópico(s): Algorithms and Data Compression
2015 - | Journal of Information Processing
Jakub Gajarský, Petr Hliněný, Jan Óbdržálek, Sebastian Ordyniak, Felix Reidl, Peter Rossmanith, Fernando Sánchez Villaamil, Somnath Sikdar,
We prove that graph problems with finite integer index have linear kernels on graphs of bounded expansion when parameterized by the size of a modulator to constant-treedepth graphs. For nowhere dense graph classes, our result yields almost-linear kernels. We also argue that such a linear kernelization result with a weaker parameter would fail to include some of the problems covered by our framework. We only require the problems to have FII on graphs of constant treedepth. This allows to prove linear ...
Tópico(s): Interconnection Networks and Systems
2016 - Elsevier BV | Journal of Computer and System Sciences
Felix Reidl, Fernando Sánchez Villaamil, Konstantinos Stavropoulos,
We show that a graph class G has bounded expansion if and only if it has bounded r-neighbourhood complexity, i.e. for any vertex set X of any subgraph H of G ∈ G, the number of subsets of X which are exact r-neighbourhoods of vertices of H on X is linear in the size of X.This is established by bounding the r-neighbourhood complexity of a graph in terms of both its r-centred colouring number and its weak r-colouring number, which provide known characterisations to the property of bounded expansion.
Tópico(s): graph theory and CDMA systems
2018 - Elsevier BV | European Journal of Combinatorics
Erik D. Demaine, Felix Reidl, Peter Rossmanith, Fernando Sánchez Villaamil, Somnath Sikdar, Blair D. Sullivan,
This research establishes that many real-world networks exhibit bounded expansion2, a strong notion of structural sparsity, and demonstrates that it can be leveraged to design efficient algorithms for network analysis. Specifically, we give a new linear-time fpt algorithm for motif counting and linear time algorithms to compute localized variants of several centrality measures. To establish structural sparsity in real-world networks, we analyze several common network models regarding their structural ...
Tópico(s): Bioinformatics and Genomic Networks
2019 - Elsevier BV | Journal of Computer and System Sciences
Fernando Villaamil Pérez, María Isabel Jociles Rubio,
AIDS has been a major challenge to the Spanish LGBT community, not only from an epidemiological, but also from a social and cultural perspective: risk of HIV transmission and seropositivity had to be incorporated into community-building practices in a context of accelerated social change. In this article we try to approach these processes by focusing on the changes that have taken place in the scene of venues where sex is practiced on premises in Madrid. The emergence of sex clubs in the last decade ...
Tópico(s): LGBTQ Health, Identity, and Policy
2011 - SAGE Publishing | Sexualities
Fernando Villaamil Pérez, María Isabel Jociles Rubio,
Se presentan los resultados de una investigación etnográfica acerca de la diversidad de prácticas y representaciones y, por tanto, de subjetividades que caracterizan a los hombres que tienen relaciones sexuales con hombres (HSH) que frecuentan los locales comerciales de encuentro sexual (LCES) del ambiente de Madrid (España). En primer lugar, se describen las formas de pensar, actuar y sentir con respecto a estos locales de tres sectores entre los usuarios, a los que hemos denominado "integrados", "periféricos" ...
Tópico(s): HIV, Drug Use, Sexual Risk
2008 - Centro em Rede de Investigação em Antropologia | Etnografica
Matthew Farrell, Timothy D. Goodrich, Nathan Lemons, Felix Reidl, Fernando Sánchez Villaamil, Blair D. Sullivan,
We establish the conditions under which several algorithmically exploitable structural features hold for random intersection graphs, a natural model for many real-world networks where edges correspond to shared attributes. Specifically, we fully characterize the degeneracy of random intersection graphs, and prove that the model asymptotically almost surely produces graphs with hyperbolicity at least $$\log {n}$$ . Further, we prove that when degenerate, the graphs generated by this model belong to a bounded- ...
Tópico(s): Complex Network Analysis Techniques
2015 - Springer Science+Business Media | Lecture notes in computer science
María Isabel Jociles Rubio, Fernando Villaamil Pérez,
En este artículo, los autores analizan las configuraciones que adoptan las reconstituciones familiares tras el divorcio desde la perspectiva de las dos lógicas que, de acuerdo a diversos especialistas, caracterizarían a dichas reconstituciones –la lógica de la sustitución (en la que el padre/ biológico/ no custodio/ es sustituido/ por la madrastra/padrastro) y la lógica de la perennidad (dirigida a mantener el rol y la posición del primero tras dicha reconstitución familiar)–, los autores desarrollan ...
Tópico(s): Gender, Health, and Social Inequality
2013 - Elsevier BV | Revista Mexicana de Ciencias Políticas y Sociales
Tópico(s): Gender and Feminist Studies
2006 - Servicio de Publicaciones | Revista de Antropología Social
Katrin Casel, Jan Dreier, Henning Fernau, Moritz Gobbert, Philipp Kuinke, Fernando Sánchez Villaamil, Markus L. Schmid, Erik Jan van Leeuwen,
An independency (cliquy) tree of an n-vertex graph G is a spanning tree of G in which the set of leaves induces an independent set (clique). We study the problems of minimizing or maximizing the number of leaves of such trees, and fully characterize their parameterized complexity. We show that all four variants of deciding if an independency/cliquy tree with at least/most ℓ leaves exists parameterized by ℓ are either Para-NP- or W[1]-hard. We prove that minimizing the number of leaves of a cliquy ...
Tópico(s): semigroups and automata theory
2018 - Elsevier BV | Discrete Applied Mathematics
Li-Hsuan Chen, Felix Reidl, Peter Rossmanith, Fernando Sánchez Villaamil,
Treedepth is a well-established width measure which has recently seen a resurgence of interest. Since graphs of bounded treedepth are more restricted than graphs of bounded tree- or pathwidth, we are interested in the algorithmic utility of this additional structure. On the negative side, we show with a novel approach that the space consumption of any (single-pass) dynamic programming algorithm on treedepth decompositions of depth d cannot be bounded by (2−ϵ)d·logO(1)n for Vertex Cover, (3−ϵ)d·logO( ...
Tópico(s): Computational Geometry and Mesh Generation
2018 - Multidisciplinary Digital Publishing Institute | Algorithms
Philipp Kranen, Felix Reidl, Fernando Sánchez Villaamil, Thomas Seidl,
In stream data mining, stream clustering algorithms provide summaries of the relevant data objects that arrived in the stream. The model size of the clustering, i.e. the granularity, is usually determined by the speed (data per time) of the data stream. For varying streams, e.g. daytime or seasonal changes in the amount of data, most algorithms have to heavily restrict their model size such that they can handle the minimal time allowance. Recently the first anytime stream clustering algorithm has ...
Tópico(s): Time Series Analysis and Forecasting
2011 - Springer Science+Business Media | Lecture notes in computer science
María Isabel Jociles Rubio, Fernando Villaamil Pérez,
Tópico(s): Aging, Health, and Disability
2008 - Elsevier BV | Revista Mexicana de Ciencias Políticas y Sociales
María Isabel Jociles Rubio, Fernando Villaamil Pérez,
Crida l’atenció que els autors que han estudiat el tema no hagin extret, en els seus estudis sobre les famílies reconstituïdes, totes les conseqüències possibles de la idea de constel·lació familiar, en especial la que manté que, en aquests estudis, el concepte de família s’ha d’estendre més enllà de la residència. Potser per això tampoc no s’ha aplicat a l’anàlisi de la paternitat i la maternitat dins d’aquesta modalitat de famílies. En la investigació els resultats de la qual presentem aquí, aquesta ...
Tópico(s): Social Sciences and Policies
2008 - Autonomous University of Barcelona | Papers Revista de Sociologia
The incorporation of HIV prevention into medical care is a central element of the redefinition of HIV prevention policies currently underway. In this article, I explore how safer sexual practices are promoted in doctor–patient encounters in the context of treatment of HIV infection in Madrid, Spain. Issues pertaining to the sexuality of people with HIV were usually absent after the initial visit, despite national and international recommendations that these be addressed. This absence is analyzed ...
Tópico(s): Feminism, Gender, and Sexuality Studies
2013 - Taylor & Francis | Medical Anthropology
Fernando Villaamil Pérez, María Isabel Jociles Rubio, Fernando Lores,
En este artículo se expone un modelo de análisis elaborado a partir de los resultados de una investigación realizada a
Tópico(s): HIV/AIDS oral health manifestations
2005 - Spanish National Research Council | Revista Internacional de Sociología
María Isabel Jociles Rubio, Fernando Villaamil Pérez,
Llama la atención que autores como Théry (1985), Le Gall y Martin (1993) y Le Gall (1996) no hayan extraído, en sus estudios sobre las familias reconstituidas, todas las consecuencias posibles de la idea de constelación familiar, en especial la que sostiene que el concepto de familia debe extenderse más allá de la residencia. Y llama asimismola atención que no la hayan aplicado al análisis de la paternidad y la maternidad dentro de esta modalidad de familias. En la investigación cuyos resultados se ...
Tópico(s): Aging, Health, and Disability
2008 - University of Toronto Press | Anthropologica
Òscar Guasch, Josep María Mesquida, Jordi Caïs,
... en España 1914–1990 (Barcelona-Madrid: Egales, 2004); Fernando Villaamil, La transformación de la identidad gay en España ( ...
Tópico(s): Latin American and Latino Studies
2023 - Taylor & Francis | Journal of Tourism History
Tópico(s): Spanish Literature and Culture Studies
2022 - Routledge | Hispanic Research Journal
Óscar Alzaga Villaamil, Fernando Reviriego Picón,
Tópico(s): Comparative constitutional jurisprudence studies
2017 - CIG Media Group | Cuestiones Constitucionales Revista Mexicana de Derecho Constitucional
Fernando Villaamil Pérez, María Isabel Jociles Rubio,
En el periodo 2009-2010 realizamos una investigacion sobre los tratamientos antirretrovirales en las consultas hospitalarias de la Comunidad de Madrid (Espana), cuyos resultados, que nacieron con vocacion de servir a la mejora de esos tratamientos, se presentan en parte aqui. Recurrimos a un modelo transaccional de la relacion medico-paciente para comprender los limites y potencialidades de la consulta entendida como espacio social y formativo en torno al cumplimiento del tratamiento. Constatamos ...
Tópico(s): HIV, Drug Use, Sexual Risk
2013 - National University of Central Buenos Aires | Intersecciones en antropología
In this article I try to explore a possible conceptualization of the body and subjectification technologies, considering them not as different entities but in their mutual conformation. To do this I propose to review the transformation of a medical technology, HIV testing, into a preventive technol-ogy. I am particularly interested in addressing the HIV test from the point of view of the bodies that it enacts in specific moral economies. I work through the narrative of the circumstances in which ...
Tópico(s): HIV, Drug Use, Sexual Risk
2013 - Complutense University of Madrid | Política y Sociedad
Jaime García-Iglesias, Angélica Cabezas‐Pino, Francisco Javier Membrillo de Novales, Axel Rodrigo Bautista Pérez, Jorge Garrido Fuentes, Fernando Villaamil Pérez, Alfonso J. Rodríguez‐Morales, Diego Zamora Estay, Edith Guajardo Zuñiga, Lucas J Núñez Saavedra, Emilio de Benito Cañizares,
Tópico(s): Zoonotic diseases and public health
2024 - Elsevier BV | The Lancet
Jakub Gajarský, Jan Óbdržálek, Sebastian Ordyniak, Felix Reidl, Peter Rossmanith, Fernando Sánchez Villaamil, Somnath Sikdar,
We show that the optimization versions of the Pathwidth and Treewidth problems have a property called finite integer index when the inputs are restricted to graphs of bounded pathwidth and bounded treewidth, respectively. They do not have this property in general graph classes. This has interesting consequences for kernelization of both these (optimization) problems on certain sparse graph classes. In the process we uncover an interesting property of path and tree decompositions, which might be of ...
Tópico(s): Complexity and Algorithms in Graphs
2014 - Springer Science+Business Media | Lecture notes in computer science
Blair D. Sullivan, Matthew Farrell, Fernando Sánchez Villaamil, Felix Reidl, Nathan Lemons, Timothy D. Goodrich,
We establish the conditions under which several algorithmically exploitable structural features hold for random intersection graphs, a natural model for many real-world networks where edges correspond to shared attributes. Specifically, we fully characterize the degeneracy of random intersection graphs, and prove that the model asymptotically almost surely produces graphs with hyperbolicity at least log(n). Further, we prove that in the parametric regime where random intersection graphs are degenerate ...
Tópico(s): Advanced Graph Theory Research
2017 - Taylor & Francis | Internet Mathematics