Modeling human behavior in user-adaptive systems: recent advances using soft computing techniques

Adaptive Hypermedia systems are becoming more important in our everyday activities and users are expecting more intelligent services from them. The key element of a generic adaptive hypermedia system is the user model. Traditional machine learning techniques used to create user models are usually too rigid to capture the inherent uncertainty of human behavior. In this context, soft computing techniques can be used to handle and process human uncertainty and to simulate human decision-making. This paper examines how soft computing techniques, including fuzzy logic, neural networks, genetic algorithms, fuzzy clustering and neuro-fuzzy systems, have been used, alone or in combination with other machine learning techniques, for user modeling from 1999 to 2004. For each technique, its main applications, limitations and future directions for user modeling are presented. The paper also presents guidelines that show which soft computing techniques should be used according to the task implemented by the application

Results for Channel Error Profiles for DECT

This letter presents the main statistical characterization of the underlying error process obtained in the case of the Digital European Cordless Telecommunications (DECT) radio system. By simulation of the transmission link, error sequences are generated for different channel parameters. Relevant statistics are then computed for the purpose of efficient channel coding design and evaluation

Stromal vascular fraction obtained from subcutaneous adipose tissue: ex-obese and older population as main clinical targets

Introduction Human adipose tissue contains a heterogeneous and synergistic mixture of cells called stromal vascular fraction (SVF) with highly proliferative and angiogenic properties, conferring promising applicability in the field of regenerative medicine. This study aims to investigate if age, body mass index (BMI), history of obesity and massive weight loss, and harvest site are related to SVF cell marker expression. Methods A total of 26 samples of subcutaneous adipose tissue were harvested from patients admitted to the Plastic and Reconstructive department in University Hospital Center of São João, Porto, Portugal, for body contouring surgery. The percentage of cells expressing CD31, CD34, CD45, CD73, CD90, and CD105 was assessed and compared with patient's age, BMI, history of obesity and massive weight loss (ex-obese group), and harvest site. Results In the ex-obese group, a significantly higher number of cells expressing CD90 (P = 0.002) was found. BMI, harvest site, and age appear to have no association with SVF subpopulations

Numerical modelling of concrete curing, regarding hydration and temperature phenomena

A numerical model that accounts for the hydration and aging phenomena during the early ages of concrete curing is presented in a format suitable for a finite element implementation. Assuming the percolation of water through the hydrates already formed as the dominant mechanism of cement hydration, the model adopts an internal variable called hydration degree, whose evolution law is easily calibrated and allows an accurate prediction of the hydration heat production. Compressive strength evolution is related to the aging degree, a concept that accounts for the influences of the hydration and curing temperature on the final mechanical properties of concrete. The model capabilities are illustrated by means of a wide set of experimental tests involving ordinary and high performance concretes, and through the simulation of the concrete curing on a viaduct deck of the Öresund Link

Interfollicular epidermal stem cells: boosting and rescuing from adult skin

Publicado na série "Methods in Molecular Biology", vol. 989 (2013), ISSN 1064-3745Epidermal stem cells isolation struggle remains, mainly due to the yet essential requirement of well-defined approaches and markers. The herein proposed methodology integrates an assemblage of strategies to accomplish the enrichment of the interfollicular epidermal stem cells multipotent fraction and their subsequent separation from the remaining primary human keratinocytes culture. Those include rapid adherence of freshly isolated human keratinocytes to collagen type IV through the β 1-integrin ligand and Rho- Associated Protein Kinase Inhibitor Y- 27632 administration to the cultures, followed by an immunomagnetic separation to obtain populations based in the combined CD49f bri /CD71 dim expression. Flow cytometry is the supporting method to analyze the effect of the treatments over the expression rate of early epidermal markers keratins19/5/14 and in correlation to CD49f bri /CD71 dim subpopulations. The stepby- step methodology herein described indulges the boosting and consecutive puri fi cation and separation of interfollicular epidermal stem cells from human keratinocytes cultures.(undefined

11HDL-induced cardioprotection is independent of the HDL receptor, scavenger receptor B1

Purpose: High-density lipoproteins (HDL) are atheroprotective. New evidence shows that HDL has widespread actions, including protection against cardiac ischemia reperfusion injury (IRI). This cardioprotective role has been attributed to several constituents of the HDL particle, including apolipoprotein A1 (apoA1) the major protein constituent and sphingosine-1-phosphate (S1P). However, the exact mechanisms of HDL-induced cardioprotection are still unknown and are under intensive investigation. A particular unresolved question remains the specific role of the HDL receptor, Scavenger Receptor BI (SR-BI), in the heart. The latter mediates many of the intracellular effects of HDL. The aim of this study was to evaluate the specific role of SR-BI in the protective impact of HDL on the heart. Methods and Results: The effects of HDL on the heart was evaluated in vitro using rat cultured neonatal cardiomyocytes and ex vivo in mice using the isolated heart Langendorff model of IRI (global no flow ischemia 35min, reperfusion 60min). In this model, HDL (400μg/mL) was injected during the first 7min of reperfusion and infarct size was assessed by triphenyltetrazolium chloride (TTC) staining. The specific role of SR-BI was investigated in vitro using specific siRNA facilitated knockdown and ex vivo using SR-BI knockout (SR-BI KO) mice. We confirmed that SR-BI is expressed in the cardiomyocytes and that HDL binds specifically to these cells. Treatment of cardiomyocytes with HDL induced the activation of several prosurvival signalling proteins, including Akt, STAT3 and ERK1/2 and protected the cells against oxidative stress induced by doxorubicin. Although specific binding of HDL was significantly reduced in SR-BI knockdown cardiomyocytes, activation of the prosurvival pathways was not affected. Similarly, SR-BI knockdown did not reduce the in vitro protective influence of HDL against oxidative stress induced by doxorubicin. Ex vivo, IRI induced an infarct size of 17.3±0.6% in isolated hearts of wildtype mice. HDL treatment during the first phase of reperfusion significantly reduced the infarct size by approximately 35% (p<0.05). This protective effect induced by HDL is maintained in SR-BI KO mice (40% of infarct size reduction (p<0.05) compared to non-treated SR-BI-KO mice). Conclusion: This is the first time that the specific role of SR-BI in the impact of HDL on the heart is investigated. Our results do not support a role for the HDL receptor SR-BI in the protective influence of HDL. Further investigations will be required to elucidate the exact mechanisms of HDL-induced cardioprotectio

Sulfonic groups induce formation of filopodia in mesenchymal stem cells

Glycosaminoglycans (GAGs) are an integral part of the extracellular matrix and glycocalix, i.e. the closest cellular environment. They are abundant in –OH groups and their bioactivity is also associated with the presence of negatively charged –SO3H functionalities. Therefore, we have investigated and discussed the influence of these functional units on mesenchymal stem cells (MSCs) behaviour using single component and mixed self-assembled monolayers of alkanethiols with –SO3H and –OH end groups. In the absence of serum, MSCs attachment, spreading, cytoskeleton organisation and motility were significantly influenced by the surface chemistry. We found that the sulfonic groups induce starlike cell shape with very intense actin staining and a high density net of filopodia that enlarge from the base of lamellipodia structures. Moreover, this response is concentration dependent and is apparent only for very short culture time in the presence of serum.Fundação para a Ciência e a Tecnologia (FCT