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Publicações

Publicações por LIAAD

2013

Clinical prognostic factors for disabling Crohn's disease: A systematic review and meta-analysis

Autores
Dias, CC; Rodrigues, PP; da Costa Pereira, A; Magro, F;

Publicação
WORLD JOURNAL OF GASTROENTEROLOGY

Abstract
AIM: To identify demographic and clinical factors associated with disabling Crohn's disease (CD). METHODS: A systematic review and meta-analysis of observational studies, focusing on the factors that can predict the prognosis of different outcomes of CD was undertaken. PubMed, ISI Web of Knowledge and Scopus were searched to identify studies investigating the above mentioned factors in adult patients with CD. Studies were eligible for inclusion if they describe prognostic factors in CD, with inclusion and exclusion criteria defined as follows. Studies with adult patients and CD, written in English and studying association between clinical factors and at least one prognosis outcome were included. Meta-analysis of effects was undertaken for the disabling disease outcome, using odds ratio (OR) to assess the effect of the different factors in the outcome. The statistical method used was MantelHaenszel for fixed effects. The 16-item quality assessment tool (QATSDD) was used to assess the quality of the studies (range: 0-42). RESULTS: Of the 913 papers initially selected, sixty studies were reviewed and three were included in the systematic review and meta-analysis. The global QATSDD scores of papers were 18, 21 and 22. Of a total of 1961 patients enrolled, 1332 (78%) were classified with disabling disease five years after diagnosis. In two studies, age at diagnosis was a factor associated with disabling disease five years after diagnosis. Individuals under 40 years old had a higher risk of developing disabling disease. In two studies, patients who were treated with corticosteroids on the first flare developed disabling disease five years after diagnosis. Further, perianal disease was found to be relevant in all of the studies at two and five years after diagnosis. Finally, one study showed localization as a factor associated with disabling disease five years after diagnosis, with L3 being a higher risk factor. This meta-analysis showed a significantly higher risk of developing disabling disease at five years after initial diagnosis among patients younger than 40 years of age (OR = 2.47, 95% CI: 1.74-3.51), with initial steroid treatment for first flare (OR = 2.42, 95% CI: 1.87-3.11) and with perianal disease (OR = 2.00, 95% CI: 1.41-2.85). CONCLUSION: Age at diagnosis, perianal disease, initial use of steroids and localization seem to be independent prognostic factors of disabling disease.

2013

Predisposition, Insult/Infection, Response and Organ Dysfunction (PIRO): A Pilot Clinical Staging System for Hospital Mortality in Patients with Infection

Autores
Cardoso, T; Teixeira Pinto, A; Rodrigues, PP; Aragao, I; Costa Pereira, A; Sarmento, AE;

Publicação
PLOS ONE

Abstract
Purpose: To develop a clinical staging system based on the PIRO concept (Predisposition, Infection, Response and Organ dysfunction) for hospitalized patients with infection. Methods: One year prospective cohort study of all hospitalized patients with infection (n = 1035), admitted into a large tertiary care, university hospital. Variables associated with hospital mortality were selected using logistic regressions. Based on the regression coefficients, a score for each PIRO component was developed and a classification tree was used to stratify patients into four stages of increased risk of hospital mortality. The final clinical staging system was then validated using an independent cohort (n = 186). Results: Factors significantly associated with hospital mortality were . for Predisposition: age, sex, previous antibiotic therapy, chronic hepatic disease, chronic hematologic disease, cancer, atherosclerosis and a Karnofsky index, 70; . for Insult/Infection: type of infection . for Response: abnormal temperature, tachypnea, hyperglycemia and severity of infection and . for Organ dysfunction: hypotension and SOFA score >= 1. The area under the ROC curve (CI95%) for the combined PIRO model as a predictor for mortality was 0.85 (0.82-0.88). Based on the scores for each of the PIRO components and on the cut-offs estimated from the classification tree, patients were stratified into four stages of increased mortality rates: stage I: <= 5%, stage II: 6-20%, stage III: 21-50% and stage IV: >50%. Finally, this new clinical staging system was studied in a validation cohort, which provided similar results (0%, 9%, 31% and 67%, in each stage, respectively). Conclusions: Based on the PIRO concept, a new clinical staging system was developed for hospitalized patients with infection, allowing stratification into four stages of increased mortality, using the different scores obtained in Predisposition, Response, Infection and Organ dysfunction. The proposed system will likely help to define inclusion criteria in clinical trials as well as tailoring individual management plans for patients with infection.

2013

Rule Induction for Sentence Reduction

Autores
Cordeiro, J; Dias, G; Brazdil, P;

Publicação
PROGRESS IN ARTIFICIAL INTELLIGENCE, EPIA 2013

Abstract
Sentence Reduction has recently received a great attention from the research community of Automatic Text Summarization. Sentence Reduction consists in the elimination of sentence components such as words, part-of-speech tags sequences or chunks without highly deteriorating the information contained in the sentence and its grammatical correctness. In this paper, we present an unsupervised scalable methodology for learning sentence reduction rules. Paraphrases are first discovered within a collection of automatically crawled Web News Stories and then textually aligned in order to extract interchangeable text fragment candidates, in particular reduction cases. As only positive examples exist, Inductive Logic Programming (ILP) provides an interesting learning paradigm for the extraction of sentence reduction rules. As a consequence, reduction cases are transformed into first order logic clauses to supply a massive set of suitable learning instances and an ILP learning environment is defined within the context of the Aleph framework. Experiments evidence good results in terms of irrelevancy elimination, syntactical correctness and reduction rate in a real-world environment as opposed to other methodologies proposed so far.

2013

Comparing Strategies of Collaborative Networks for R&D: An Agent-Based Study

Autores
Campos, P; Brazdil, P; Mota, I;

Publicação
COMPUTATIONAL ECONOMICS

Abstract
In this work we analyze the evolving dynamics of different strategies of collaborative networks that emerge from the creation and diffusion of knowledge. An evolutionary economic approach is adopted by introducing decision rules that are applied routinely and an agent-based model is developed. Firms (the agents) can collaborate and create networks for research and development purposes. We have compared three collaboration strategies (A-peer-to-peer complementariness, B-concentration process and C-virtual cooperation networks) that were defined on the basis of literature and on empirical evidence. Strategies are introduced exogenously in the simulation. The aims of this paper are twofold: (i) to analyze the importance of the networking effects; and (ii) to test the differences among collaboration strategies. It was possible to conclude that profit is associated with higher stock of knowledge and with smaller network diameter. In addition, concentration strategies are more profitable and more efficient in transmitting knowledge through the network. These processes reinforce the stock of knowledge and the profit of the firms located in the centers of the networks.

2013

Real-time Augmented Reality Demo Platform for Exploring Consumer Emotional Responses with Shopping Applications

Autores
Stoyanova, J; Gonçalves, R; Brito, PQ; Coelho, A;

Publicação
Int. J. Online Biomed. Eng.

Abstract
The present-day revival of Augmented reality (AR) technology has led to its vast expansion in various applications. In marketing, the hunt for more inventive and intriguing approaches for immersive consumer experiences has endorsed the implementation of AR in multiple brand advertising campaigns, specifically for improved product display. The engaging potential of this technology is established in the fusion between computer-generated data and the physical world as seen by the user, where 3D registration and real time interaction are inseparable parts of this system. Alternatively, impressions from user experiences serve as a principal instrument in the evaluation process of the effectiveness of interactive systems. In order to get deeper insight into consumers' reflections from a real-time AR shopping experience, we present a demo platform for the purchase of sneakers, focusing on users' behavior and more precisely on their perceptions, emotions, personal preferences before, during and after use of the platform. To fully evaluate and compare consumer experiences with the main AR platform, two other shopping systems were designed: a marker-based and a static one. Consecutively, we aim at defining a system of metrics for measuring shopping experiences with AR, as well as at establishing a ground base for subsequent marketing research in the field. Motivated by the large application of the technology and aiming at understanding the impact of AR on consumer psychology, the application will assist in exploring the antecedents of consumer purchase intentions.

2013

Real-time Augmented Reality shopping platform for studying consumer cognitive experiences

Autores
Stoyanova, J; Goncalves, R; Coelho, A; Brito, P;

Publicação
2013 2ND EXPERIMENT@ INTERNATIONAL CONFERENCE (EXP.AT'13)

Abstract
Augmented Reality (AR) is a technology which produces a synthesis between a computer-generated data and the physical world of a viewer while establishing 3D registration and real time interaction. Among the wide range of application of AR, its use in advertising shopping experiences has recently been embraced by advertisers due to its novelty and engaging potential. Part of a wider research aiming at understanding the impact of AR on consumer psychology, this paper presents a demo platform application developed for a real-time shopping experience for shoes and attempts to define a ground base for posterior marketing research in the field. In order to fully evaluate consumer experiences and compare with the main AR platform two other shopping applications were designed: a marker-based and a static one. The platform will assist in exploring the antecedents of consumer purchase intention and in defining metrics for measuring shopping experiences with AR.

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