Determination of unzipping step-size distribution using Hidden Markov Models

Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Any: 2015, Tutor: Félix RitortIn this paper we explain the unzipping experiment as well as the basic theory of hidden Markov models (HMM). Using a specific type of HMMs, variable step-size HMM, in which the quantized distance variable is represented by a large number of states of the Markov model we try to determine the size distribution of the steps in the unzipping process

Hogna radiata males do not deplete their sperm in a single mating

To the extent that sperm production or mating opportunities are limited, males are expected to allocate their sperm optimally, so as to increase their overall fitness. Among spiders, sperm depletion and monogyny are known to be optimal male mating decisions either under strong sperm competition or as terminal investment strategies, when future mating opportunities are limited. In a medium-sized wolf spider, Hogna radiata (Latreille 1817), we investigated sperm depletion, terminal sperm investment and the potential for sperm competition in laboratory mating trials in which we allowed males and females to pair sequentially with two mates. Males mated with as many females as they encountered. We found no evidence of sperm depletion or terminal sperm investment, as mating duration and female fitness were unaffected by male mating history or age. Polyandry was rare and did not involve any clear fitness benefit to females, whereas premating sexual cannibalism was a rather common outcome of mating interactions involving inseminated females. Our results indicate that H. radiata males are not sperm limited and support the hypothesis that the potential for sperm competition shapes the evolution of sperm allocation in this species. Monandrous females do not incur any fitness cost and could potentially benefit from cannibalizing their prospective mates.This study was financially supported by the Spanish Ministerio de Educación y Cultura to C.F.M. (BSO2002-03264)

Geometric morphometrics reveals sex-differential shape allometry in a spider

Common scientific wisdom assumes that spider sexual dimorphism (SD) mostly results from sexual selection operating on males. However, testing predictions from this hypothesis, particularly male size hyperallometry, has been restricted by methodological constraints. Here, using geometric morphometrics (GMM) we studied for the first time sex-differential shape allometry in a spider (Donacosa merlini, Araneae: Lycosidae) known to exhibit the reverse pattern (i.e., male-biased) of spider sexual size dimorphism. GMM reveals previously undetected sexdifferential shape allometry and sex-related shape differences that are size independent (i.e., associated to the y-intercept, and not to size scaling). Sexual shape dimorphism affects both the relative carapace-to-opisthosoma size and the carapace geometry, arguably resulting from sex differences in both reproductive roles (female egg load and male competition) and life styles (wandering males and burrowing females). Our results demonstrate that body portions may vary modularly in response to different selection pressures, giving rise to sex differences in shape, which reconciles previously considered mutually exclusive interpretations about the origins of spider SDThe fieldwork was financially supported by the Ministerio de Ciencia e Innovación and the Consejo Superior de Investigaciones Científicas to CFM (022/2007). JML is endorsed by project CGL2013-42643-

Reciprocal verbs in dictionaries: polysemy and pronominalization

[Resumen] En este artículo se presenta un análisis lexicográfico de un subgrupo de la clase de los verbos recíprocos léxicos del español, que en general ha sido muy poco estudiada. Concretamente hemos estudiado 49 verbos polisémicos que presentan al menos una acepción recíproca y pronominal. En primer lugar, se constata si, tal como propone Dimitriadis (2008), cuando estos verbos adoptan el clítico, la presencia de este elemento sirve para contrastar el sentido recíproco con otros sentidos. En segundo lugar, se analiza el tratamiento que han recibido estos predicados en tres obras lexicográficas con el fin de verificar en qué porcentaje estos recursos identifican el uso simétrico de estos verbos polisémicos, teniendo en cuenta especialmente que algunos usos no recíprocos de estos predicados son muy próximos a los recíprocos. En tercer lugar, dado que en el análisis realizado se han observado ciertas ambivalencias en la representación lexicográfica de este tipo de predicados, el objetivo último es presentar una propuesta de representación lexicográfica para los usos recíprocos de estos verbos teniendo en cuenta la distinta casuística observada.[Abstract] This article presents a lexicographic analysis of a subset of verbs that belong to the class of Spanish reciprocal predicates. We have studied 49 polysemic predicates that have at least one pronominal reciprocal sense. This paper first seeks to confirm the hypothesis postulated by Dimitriadis’s (2008), which states that whenever these verbs take the clitic they do in order to help contrast the reciprocal meaning with other senses. Second, an analysis of how theses predicates are described in three different dictionaries was carried out with the aim to verify if these lexicographical resources identify symmetric uses, taking into consideration that sometimes the non-reciprocal use is semantically close to the symmetric use. Thirdly, since some ambivalence in the lexicographical representation of this class was found, our last objective was to present a representation proposal taking into account all the casuistry observed

Integration of Computers in the Classroom. The Use of the UNIX Operating System as a Tool

In this paper we present our ESP teaching experience to computer science students at the Escuela Universitaria de Informática at the UAB using the UNIX operating system as a leaming tool. Concretely we detall the new approach adopted for our practice classes