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Detalhes

Detalhes

  • Nome

    Paulo Teles
  • Cluster

    Informática
  • Cargo

    Investigador Sénior
  • Desde

    01 janeiro 2014
Publicações

2019

Clustering of interval time series

Autores
Maharaj, EA; Teles, P; Brito, P;

Publicação
Statistics and Computing

Abstract
Interval time series occur when real intervals of some variable of interest are registered as an ordered sequence along time. We address the problem of clustering interval time series (ITS), for which different approaches are proposed. First, clustering is performed based on point-to-point comparisons. Time-domain and wavelet features also serve as clustering variables in alternative approaches. Furthermore, autocorrelation matrix functions, gathering the autocorrelation and cross-correlation functions of the ITS upper and lower bounds, may be compared using adequate distances (e.g. the Frobenius distance) and used for clustering ITS. An improved procedure to determine the autocorrelation function of ITS is proposed, which also serves as a basis for clustering. The different alternative approaches are explored and their performances compared for ITS simulated under different setups. An application to sea level daily ranges, observed at different locations in Australia, illustrates the proposed methods. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.

2018

The effect of temporal aggregation on the estimation accuracy of ARMA models

Autores
Teles, P; Sousa, PSA;

Publicação
Communications in Statistics - Simulation and Computation

Abstract

2018

Radio-cephalic arteriovenous fistula recovered with drainage through the brachial vein

Autores
Norton de Matos, AN; Sousa, CN; Almeida, P; Teles, P; Rego, D; Teixeira, G; Loureiro, L; Teixeira, S;

Publicação
HEMODIALYSIS INTERNATIONAL

Abstract
Dysfunction of arteriovenous access for hemodialysis is a challenge for the vascular surgeon. Some patients have complex vascular access with problems that are difficult to solve. Careful analysis of the vascular network with ultrasound and dissection of the veins during surgery can help to identify the best option for each access. We introduce and discuss the case of creation of a radio-cephalic fistula with outflow into the brachial vein in 64-year-old hemodialysis male patient. This technique enables extending fistula patency, arterializing the brachial vein, and improves cost efficiency.

2018

Radiocephalic Fistula Recovery Using the Brachial Vein and Forearm Basilic Vein: A Case Series and Literature Review

Autores
de Matos, AN; Sousa, CN; Almeida, P; Teles, P; Rego, D; Teixeira, G; Loureiro, L; Teixeira, S; Antunes, I;

Publicação
THERAPEUTIC APHERESIS AND DIALYSIS

Abstract
Vascular access dysfunction is a serious problem in dialysis units. Some patients have complex dysfunctions that are difficult to resolve. In this article, we report the case a of two patients with radiocephalic arteriovenous fistulae (RC-AVF) who had stenosis/occlusion of the forearm median vein and where we used the basilic vein of the forearm as a solution. We reviewed the use of this surgical solution in RC-AVF. Two male patients on hemodialysis exhibited stenosis/occlusion of the forearm median vein. The forearm basilic vein was isolated and rotated toward the forearm median vein in order to solve RC-AVF problems. One patient had fistula thrombosis 5 months after the procedure, while for the other patient, the fistula continues to work without problems. Literature describes only a few cases using the forearm basilic vein or the brachial vein for fistula recovery. This procedure increased the patency of fistulas. This approach has been proven to be a good solution for solving outflow problems using the superficial or deep veins, increasing fistula patency and avoiding the need to place a central venous catheter and all the related complications.

2018

Self-care in Preserving the Vascular Network: Old Problem, New Challenge for the Medical Staff

Autores
Sousa, CN; Ligeiro, I; Teles, P; Paixao, L; Dias, VFF; Cristovao, AF;

Publicação
THERAPEUTIC APHERESIS AND DIALYSIS

Abstract
Teaching/educating patients with end stage renal disease (ESRD) and identifying their self-care behaviors for vascular network preservation are very important. However, the self-care behaviors regularly performed by patients are still unknown. We compared self-care behaviors for vascular network preservation performed by patients who are/are not followed-up by the nephrologist. The study design was a prospective, observational and comparative study. Inclusion criteria were as follows: ESRD patients (at stages 4 or 5); at least 18 years old; in pre-dialysis with at least a 6-month follow-up period by the nephrologist or who started dialysis in emergency and were not followed-up by the nephrologist; with no memory problems; and medically stable. Primary outcome was the frequency of self-care behaviors for vascular network preservation. Secondary outcome was the comparison between self-care behaviors by ESRD patients who were/were not followed-up by the nephrologist. The study involved 145 patients, 64.1% were female, the mean age was 69.5 years and the self-care behaviors mean score was 36.8% (with a SD of 39.8%). The number of patients followed-up and not followed-up by the nephrologist was 109 (group 1) and 36 (group 2), respectively. Social characteristics were similar in the two groups (P > 0.05). The mean self-care behaviors were 29.4% and 59.2% in groups 1 and 2, respectively (P = 0.000). Patients performed self-care behaviors for vascular network preservation with a relatively low frequency (the mean score was 36.8% only). Patients not followed by the nephrologist performed self-care behaviors more often than those who were followed (59.2% vs. 29.4% respectively, P = 0.000).

Teses
supervisionadas

2017

Globalização das Regiões Portuguesas – Índice de Globalização Regional

Autor
João Pedro Almeida Ferreira

Instituição
UP-FEP

2017

Determinantes do Investimento Direto Estrangeiro em Cabo Verde: evidência para o período 1986-2015

Autor
Ermelinda Andrade Santana

Instituição
UP-FEP

2017

Price Analysis of Bitcoin: Volatility, Key Drivers and Evolution

Autor
Pedro Jorge Melgo Vieira

Instituição
UP-FEP