Recognizing pro-R closures of regular languages

Given a regular language L, we effectively construct a unary semigroup that recognizes the topological closure of L in the free unary semigroup relative to the variety of unary semigroups generated by the pseudovariety R of all finite R-trivial semigroups. In particular, we obtain a new effective solution of the separation problem of regular languages by R-languages

Portugal, o Atlântico e a Europa. A Identidade Nacional, a (re)imaginação da Nação e a Construção Europeia

Desde 1974, com o seu regresso a casa e à Europa, depois do fim dum projecto nacional expansionista de cinco séculos, Portugal tem atravessado importantes mudanças estruturais que têm transformado a velha sociedade tradicional e fechada numa sociedade pós-colonial moderna e mais aberta. Este processo de reconstrução da nação tem sido acompanhado duma importante agenda de celebração da história nacional. Adoptando uma abordagem intermédia entre uma visão modernista e uma visão primordialista, argumenta-se que as nações, apesar de poderem desenvolver novas tendências, medos e mitos, abandonar velhos, mudar o seu equilíbrio interno, são formas de organização colectiva baseadas nalgum tipo de continuidade histórica e numa experiência histórica comum (Hutchinson, 1994; Jenkins, 1995; May, 2001; Parekh, 1995; Smith, 1991). Ora, muita da literatura sobre a integração europeia tem chamado a atenção para o facto de que a dificuldade da emergência duma identidade europeia assenta na permanência dos sentimentos nacionais e numa limitada oferta da União Europeia de repertórios comuns que inspirem o entusiasmo colectivo (Calhoun, 1997; Hansen & Waever, 2002; Pagden, 2002; Smith, 1996). Neste ensaio explora-se como estes dois processos de reimaginação da nação e de integração europeia acontecem em paralelo, podendo, por vezes, criar tensões e fazer apelos que os cidadãos nacionais podem perceber como sendo de sentido contrário. Por um lado o processo de reprodução da nação reafirma os sentimentos de lealdade para com a nação – definida, durante a maior parte do século XX, em oposição à industrialização, modernização e aos valores liberais e democráticos dos seus vizinhos europeus. Por outro, o aprofundar do projecto europeu implica a perda de soberania nacional num número crescente de aspectos da vida nacional

Mining protein structure data

The principal topic of this work is the application of data mining techniques, in particular of machine learning, to the discovery of knowledge in a protein database. In the first chapter a general background is presented. Namely, in section 1.1 we overview the methodology of a Data Mining project and its main algorithms. In section 1.2 an introduction to the proteins and its supporting file formats is outlined. This chapter is concluded with section 1.3 which defines that main problem we pretend to address with this work: determine if an amino acid is exposed or buried in a protein, in a discrete way (i.e.: not continuous), for five exposition levels: 2%, 10%, 20%, 25% and 30%. In the second chapter, following closely the CRISP-DM methodology, whole the process of construction the database that supported this work is presented. Namely, it is described the process of loading data from the Protein Data Bank, DSSP and SCOP. Then an initial data exploration is performed and a simple prediction model (baseline) of the relative solvent accessibility of an amino acid is introduced. It is also introduced the Data Mining Table Creator, a program developed to produce the data mining tables required for this problem. In the third chapter the results obtained are analyzed with statistical significance tests. Initially the several used classifiers (Neural Networks, C5.0, CART and Chaid) are compared and it is concluded that C5.0 is the most suitable for the problem at stake. It is also compared the influence of parameters like the amino acid information level, the amino acid window size and the SCOP class type in the accuracy of the predictive models. The fourth chapter starts with a brief revision of the literature about amino acid relative solvent accessibility. Then, we overview the main results achieved and finally discuss about possible future work. The fifth and last chapter consists of appendices. Appendix A has the schema of the database that supported this thesis. Appendix B has a set of tables with additional information. Appendix C describes the software provided in the DVD accompanying this thesis that allows the reconstruction of the present work

Active or passive recovery ? Discussing implications of vegetation diversity in unmanaged salt marshes

The interest on salt marsh recovery and habitat restoration started to be associated with rapid changes in erosion and accretion rates endangering the human communities that live in the borderline salt marsh (Boorman et al., 2002; Doody, 2013). Lowlying areas left by successive embankments and land reclamation over centuries fail in the absorption of wave energy and in the capacity to accommodate flooding. These aspects started to be valued in a context of climate change, particularly rising sea levels, and these concerns, in the first phase, have led to the construction of breakwater structures (Elliot et al., 2007; Doody, 2013). Nevertheless, these hard measures started to degrade and sustainability issues arose whenever breakwaters and groins needed repairing or reconstruction (Esteves, 2013).info:eu-repo/semantics/publishedVersio

XML::DT : a PERL down translation module

In this paper we present a Perl module, called XML::DT, that can be used to translate and transform XML documents. A programmer always looks for the simplest tool to do a certain task, development and maintenance will be easier. That is the main idea behind the module we are presenting: a simple tool that will enable the user to speed up his work and that will help him to maintain it. XML::DT includes some down translation features that are common to other SGML/XML processors available on the market like Omnimark, or Balise, and some other features to deal with input and output of Unicode character sets. The idea was to adopt familiar concepts together with a familiar syntax to SGML/XML programmers but shaped to the usual Perl notation.GC

Pointlike sets with respect to R and J

We present an algorithm to compute the pointlike subsets of a finite semigroup with respect to the pseudovariety R of all finite R-trivial semigroups. The algorithm is inspired by Henckell’s algorithm for computing the pointlike subsets with respect to the pseudovariety of all finite aperiodic semigroups. We also give an algorithm to compute J-pointlike sets, where J denotes the pseudovariety of all finite J-trivial semigroups. We finally show that, in contrast with the situation for R, the natural adaptation of Henckell’s algorithm to J computes pointlike sets, but not all of them.Pessoa French-Portuguese project Egide- Grices 11113YMFundação para a Ciência e a Tecnologia (FCT

Iterated periodicity over finite aperiodic semigroups

This paper provides a characterization of pseudowords over the pseudovariety of all finite aperiodic semigroups that can be described from the free generators using only the operations of multiplication and omega-power. A necessary and sufficient condition for this property to hold turns out to be given by the conjunction of two rather simple finiteness conditions: the nonexistence of infinite anti-chains of factors and the rationality of the language of McCammond normal forms of omega-terms that define factors of the given pseudoword. The relationship between pseudowords with this property and arbitrary pseudowords is also investigated.Projeto PTDC/MAT/65481/2006 financiado em parte pelo European Community Fund FEDERPrograma AutoMathA da European Science Fundation (ESF)Projeto Egide-Grices 11113YMFundação para a Ciência e a Tecnologia (FCT

ω-terms over finite aperiodic semigroups

This paper provides a characterization of pseudowords over the pseudovariety of all finite aperiodic semigroups that are given by w-terms, that is that can be obtained from the free generators using only multiplication and the w-power. A necessary and sufficient condition for this property to hold turns out to be given by the conjunction of two rather simple finiteness conditions: the nonexistence of infinite anti-chains of factors and the rationality of the language of McCammond normal forms of w-terms that define factors.FCT through the Centro de Matemática da Universidade do Minho and the Centro de Matemática da Universidade do PortoEuropean Community Fund FEDE

Factoriality and the pin-reutenauer procedure

We consider implicit signatures over finite semigroups determined by sets of pseudonatural numbers. We prove that, under relatively simple hypotheses on a pseudovariety V of semigroups, the finitely generated free algebra for the largest such signature is closed under taking factors within the free pro-V semigroup on the same set of generators. Furthermore, we show that the natural analogue of the Pin-Reutenauer descriptive procedure for the closure of a rational language in the free group with respect to the profinite topology holds for the pseudovariety of all finite semigroups. As an application, we establish that a pseudovariety enjoys this property if and only if it is full.European structural funds (FEDER)European Regional Development Fund, through the program COMPET

Complete reducibility of pseudovarieties

The notion of reducibility for a pseudovariety has been introduced as an abstract property which may be used to prove decidability results for various pseudovariety constructions. This paper is a survey of recent results establishing this and the stronger property of complete reducibility for specific pseudovarieties.FCT through the Centro de Matemática da Universidade do Minho and Centro de Matemática da Universidade do Port