Matemática e Estatística / Mathematics and Statistics
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- 12th Workshop on Statistics, Mathematics and Computation In Honour of Professor Carlos Braumann: book of abstractsPublication . Oliveira, Amilcar; Nunes, Célia; Ferreira, Dário; Grilo, Luís M.; Ferreira, Sandra; Oliveira, TeresaWe celebrate this meeting in Honour of Professor Carlos Braumann, for his brilliant career and outstanding contribution to the field of Statistics in Portugal and abroad, and to whom we are deeply grateful for all the support, kind and precious collaboration in our meetings! We are delighted to have this celebration fostering strong interaction between national and international researchers, leading to a successful com mitment and enthusiasm on promoting research in and between the broad areas of Statistics, Mathematics and Computation. It is a great pleasure to receive all our guests and contributors from 9 to 10 th November in UBI Universidade da Beira Interior, expressing our huge gratitude to the Univer sity Coordinators for kindly accepted to embrace this challenge of receiving us again! The WSMC was successfully organized in several places along these last 12 years and we believe that our meetings have been creating very nice opportunities for showcasing the growth and development of the focused main areas, at a time when so many new technologies are available and huge challenges are emerging. The idea exchanges between participants are al ways helpful for generating positive impact on propelling the advancement of science and technology and some of these results have been published in high standard Journals, special issues and Springer Series Books. Also in this 12th WSMC edition the participants will have several journal oppor tunities for papers submission. Selected papers, after review, will appear in Journal of Applied Statistics, Biometrical Letters, Biometrics & Biostatis tics International Journal (BBIJ) and in a new Springer volume of the Series Contributions to Statistics. We are hightly grateful to all the participants, Invited Speakers, Session Organizers and Authors who submitted abstracts, for their valuable contri bution and for the enthusiastic way how they assume their participation. We also acknowledge all the sponsors and contributors who made this meeting a reality. Furthermore, we acknowledge the Rector of Universidade da Beira Interior, the Rector of Universidade Aberta, the Coordinator of the Centro de Estatística e Aplicações da Universidade de Lisboa and the President of the Committee on Risk Analysis of International Statistical Institute, for v vi Preface their support. We are most grateful to all the members of the Organizing Committee and of the Scientific Committee for their crucial help and sugges tions. We address a deeply thanks to the Local Chair, Sandra Ferreira, and also to Amílcar Oliveira, Célia Nunes, Dário Ferreira and Luís Grilo for their invaluable contribution on organizing the Webpage, the final programme, the Book of Abstracts and so many details in a such incredible short time! Finally, the venue adds an important attraction to the meeting. The destination city, Covilhã, is a fantastic place close to beautiful and highest mountain in Portugal, Serra da Estrela. This region is very famous not only for awesome landscapes and sports opportunities but also for the famous de lights like the wool cheese, ham, licors and also for the traditional artesanat. Covilhã offers a full calendar of traditional festivals and holidays celebrated throughout the year adds to its cultural appeal. We trust that you will find the conference and your visit to the very beautiful city of Covilhã in November 2018 both valuable and enjoyable, we believe that this meeting will be rewarding to all of us and that it will draw us to the next edition -WSMC13, which is planned for 2019 in Lisbon.
- 13th Conference on Statistics, Mathematics and Computation: book of abstractsPublication . Oliveira, Amilcar; Ferreira, Dário; Ferreira, Sandra; Oliveira, Teresa A.We celebrate this meeting in Honour of Professor João Tiago Mexia, for his brilliant career and outstanding contribution to the field of Statistics in Portugal and abroad, and to whom we are deeply grateful for all the support, kindness and precious collaboration in our meetings! We are delighted to have this celebration, fostering strong interaction between national and international researchers, leading to a successful com mitment and enthusiasm on promoting research in and between the broad areas of Statistics, Mathematics and Computation. It is a great pleasure to receive all our guests and contributors from 3 to 5th June in the Aberta University, and we emphasize our huge gratitude to the Magnificent Rector, for kindly accepting to embrace this challenge of hosting once more this International Conference! The WSMC was successfully organized in several places along the 13 editions and we believe that our meetings have been creating very nice op portunities for showcasing the growth and development of the focused main areas, in a time underlined by so many new technologies and huge emerging challenges. The scientific exchanges of ideas between participants is always helpful for generating positive impact on propelling the advancement of sci ence and technology and some of these results have already been successfully published in high standard Journals, special issues and Springer Series Books. Also now, in this 13th edition, the participants have the opportunity to submit their work to high referenced Journals and Book volumes. Selected papers, after peer review, will appear in the Chilean Journal of Statistics (ChJS), Journal of Applied Statistics (JAS), Biometrical Letters, Biometrics & Biostatistics International Journal (BBIJ) and in Springer volumes of the Series Contributions to Statistics. Details will be soon announced in our webpage. We are highly grateful to all the participants, Invited Speakers, members of Scientific Committee, Session Organizers and Authors who submitted ab v vi Preface stracts, for their valuable contribution and for the enthusiastic way how their participation is assumed! We greatly acknowledge all the sponsors and contributors who made this meeting a reality and we reinforce the importance of our social programme. This year it includes the nice opportunity to visit the National Museum of Natural History and Science and the Botanical Garden, allowed all the week, from 3 to 9 of June - during and after WSMC13. We are really grateful to the Director of the Department of Museums Management Support and IICT, Dr Vitor Lucas and to his team, for kindly offering this outstanding opportunity to all the participants of WSMC13. A deeply thanks is addressed to all the members of the Organizing Com mittee, emphasizing the invaluable collaboration of Dr. Virginia Zaidam, the crucial help of the Gabinete de Comunicação e de Relações Internacionais UAB team, and the very hard work of Amílcar, Sandra and Dário on the organization and supervision of many of the programme and schedule de tails, preparing the website and the abstracts book in an incredible record time! Finally, as I guess most of you already noticed, Lisbon is very much enjoyable for offering a rich and varied history, a buzzing nightlife and for being blessed with a glorious year-round climate, where the sky joins the ocean and the city is kissed by the river Tagus. Please take some of your time to enjoy and take profit of it! Don’t forget to taste the famous "Pastéis de Belém" and to listen to Fado music! We wish you all a very productive and successfull meeting, as well as a pleasant and memorable stay in Lisbon, the stunning capital of Portugal!
- Abundance of elliptic dynamics on conservative three-flowsPublication . Bessa, Mário; Duarte, PedroWe consider a compact three-dimensional boundaryless Riemannian manifold M and the set of divergence-free (or zero divergence) vector fields without singularities, then we prove that this set has a C 1-residual (dense G_δ) such that any vector field inside it is Anosov or else its elliptical orbits are dense in the manifold M. This is the flow-setting counterpart of Newhouse's Theorem 1.3 (S. Newhouse, Quasi-elliptic periodic points in conservative dynamical systems, Am. J. Math. 99 (1977), pp. 1061–1087). Our result follows from two theorems, the first one says that if Λ is a hyperbolic invariant set for some class C^1 zero divergence vector field X on M, then either X is Anosov, or else Λ has empty interior. The second one says that, if X is not Anosov, then for any open set U ⊆ M there exists Y arbitrarily close to X such that Y t has an elliptical closed orbit through U.
- Acid phosphatase, some genetic polymorphism and obesity risk factors in adult womenPublication . Carolino, E.; Oliveira, T.; Silva, A. P.; Carvalho, R; Bicho, M.Recent works point out to a relation between some genetic factors and the predisposition for obesity. We believe, therefore, to be relevant to conduct this kind of study in the Portuguese population. In the present work the following genetic factors are considered: Haptoglobin phenotype, the Acid Phosphatasehenotype and two blood group systems, the MN System and the Lewis System. In addition, it was also considered one demographic factor, age, and one enzymatic activity, the Acid Phosphatase Activity. Haptoglobin (Hp) is a hemoglobin-binding protein of the immune system expressed by a genetic polymorphism with three major phenotypes. This protein is associated in some works with susceptibility for common pathological situations, such as some disorders related with obesity. The Acid phosphatase, more precisely the Acid phosphatase locus 1 (ACP1), is a highly polymorphic enzyme that has an important role in flavoenzyme activity and in the control of insulin receptor activity. High ACP1 activity was positively associated with high glycemic levels and with high body mass index (BMI) values. The MN blood system is a blood group system with three phenotypes each one showing different associations with some diseases, including some related with obesity. Finally, the Lewis System was focused on a single locus with two antigens, Le a and Le b. Confirming this characteristic as a genetic marker of obesity may contribute to the explanation of individual differences in the prevalence of obesity. The group under study involves 85 Portuguese adult women with complete data for all variables, taken from a data base with 714 subjects from the Genetic Laboratory, Centre of Endocrinology and Metabolism of University of Lisbon. The aim of the study is to explore and examine the relationship between the weight categories and the explanatory variables, with emphasis on risk for obesity. Therefore, an ordinal regression model was tried, considering as the regressor variables the Haptoglobin phenotype, Acid phosphatase (ACP1) phenotype, MN blood group system, Lewis system, the enzymatic activity of ACP1, age and some association effects between these factors. Some significant main effects were found at a 5% significance level: the phenotypeLe(a-b+) of Lewis System (p-value=0,021) and age (p-value=0,002). The phenotype Le(a-b+) of Lewis System is associated with a decreased risk for obesity (odds ratio 0,139; CI95%(0,016; 0,754)); age (as expected) is associated with an increased risk for obesity (odds ratio 1,11; CI95%(1,038; 1,190))
- Álgebra linear I : aplicações lineares: definição e exemplosPublication . Costa, Fernando Pestana da; Firmino, Joaquim; Silva, Fátima Ferreira daVídeo sobre "Aplicações lineares: definição e exemplos" para apoio à unidade curricular Álgebra Linear I da Universidade Aberta, Lisboa, Portugal.
- Álgebra linear I : cálculo de determinantes por aplicação do teorema de LaplacePublication . Costa, Fernando Pestana da; Barrela, Nuno; Silva, Fátima Ferreira daVídeo sobre " Cálculo de determinantes por aplicação do teorema de Laplace" para apoio à unidade curricular Álgebra Linear I da Universidade Aberta, Lisboa, Portugal
- Álgebra linear I : conjuntos geradores, bases e dimensão de espaços vetoriaisPublication . Costa, Fernando Pestana da; Firmino, Joaquim; Silva, Fátima Ferreira daVídeo sobre "Conjuntos geradores, bases e dimensão de espaços vetoriais" para apoio à unidade curricular Álgebra Linear I da Universidade Aberta, Lisboa, Portugal
- Álgebra linear I : diagonalizaçãoPublication . Costa, Fernando Pestana da; Silva, Fátima Ferreira da; Firmino, JoaquimVídeo sobre "Diagonalização" para apoio à unidade curricular Álgebra Linear I da Universidade Aberta, Lisboa, Portugal
- Álgebra linear I : espaços vetoriais: definição e exemplosPublication . Costa, Fernando Pestana da; Barrela, Nuno; Silva, Fátima Ferreira daVídeo sobre "Espaços vetoriais: definição e exemplos" para apoio à unidade curricular Álgebra Linear I da Universidade Aberta, Lisboa, Portugal
- Álgebra linear I : espaços vetoriais: mais exemplosPublication . Costa, Fernando Pestana da; Barrela, Nuno; Silva, Fátima Ferreira daVídeo sobre "Espaços vetoriais: mais exemplos" para apoio à unidade curricular Álgebra Linear I da Universidade Aberta, Lisboa, Portugal