Distribution of Chlamydia pneumoniae DNA in atherosclerotic carotid arteries: significance for sampling procedures

Despite extensive efforts to confirm a direct association between Chlamydia pneumoniae and atherosclerosis, different laboratories continue to report a large variability in detection rates. In this study, we analyzed multiple sections from atherosclerotic carotid arteries from 10 endartectomy patients to determine the location of C. pneumoniae DNA and the number of sections of the plaque required for analysis to obtain a 95% confidence of detecting the bacterium. A sensitive nested PCR assay detected C. pneumoniae DNA in all patients at one or more locations within the plaque. On average, 42% (ranging from 5 to 91%) of the sections from any single patient had C. pneumoniae DNA present. A patchy distribution of C. pneumoniae in the atherosclerotic lesions was observed, with no area of the carotid having significantly more C. pneumoniae DNA present. If a single random 30-mum-thick section was tested, there was only a 35.6 to 41.6% (95% confidence interval) chance of detecting C. pneumoniae DNA in a patient with carotid artery disease. A minimum of 15 sections would therefore be required to obtain a 95% chance of detecting all true positives. The low concentration and patchy distribution of C. pneumoniae DNA in atherosclerotic plaque appear to be among the reasons for inconsistency between laboratories in the results reported.

Ventricular dysfunction in early diabetic heart disease: detection, mechanisms and significance

The detection of preclinical heart disease is a new direction in diabetes care. This comment describes the study by Vinereanu and co-workers in this issue of Clinical Science in which tissue Doppler echocardiography has been employed to demonstrate subtle systolic and diastolic dysfunction in Type 11 diabetic patients who had normal global systolic function and were free of coronary artery disease. The aetiology of early ventricular dysfunction in diabetes relates to complex intramyocardial and extramyocardial mechanisms. The initiating event may be due to insulin resistance, and involves abnormal myocardial substrate utilization and uncoupling of mitochondrial oxidative phosphorylation. Dysglycaemia plays an important role via the effects of oxidative stress, protein kinase C activation and advanced glycosylation end-products on inflammatory signalling, collagen metabolism and fibrosis. Extramyocardial mechanisms involve peripheral endothelial dysfunction, arterial stiffening and autonomic neuropathy. The clinical significance of the ventricular abnormalities described is unknown. Confirmation of their prognostic importance for cardiac disease in diabetes would justify routine screening for presymptomatic ventricular dysfunction, as well as clinical trials of novel agents for correcting causal mechanisms. These considerations could also have implications for patients with obesity and the metabolic syndrome.

The host-tourist interaction in a world heritage site: the case of Guimarães

Guimarães, in the northwest of Portugal, is a city of strong symbolic and cultural significance and its nomination by UNESCO as world heritage, in 2001, enlarged its tourism potential. In this paper we present a few results of a survey that envisaged capturing the Guimarães residents’ perceptions of tourism impacts and their attitudes towards tourists. Specifically, one analyzes the type of relationship that exists between some socio-demographic groups and the perceived tourism impacts, as well as their socio-characteristics and the existing level of interaction between residents and tourists. The survey was implemented between January and March 2010 to a convenience sample of 540 inhabitants of the municipality of Guimarães resulting in 400 questionnaires with complete data. For this, we made use of various statistical techniques. Using a factorial analysis, we can conclude that the three factors used explain 52.3% of the variance contained in the original variables obtained from the survey. By another side, using a logit model in the analysis and taking as the dependent variable the frequent or very frequent contact with tourists, we found that only the variables referred to perceived positive impacts of tourism, education and the place of residence in urban areas have shown to be statistically significant. We are aware of the multiple ways the issue of residents’ perceptions and attitudes towards tourism can be approached and of the difficulties to get useful policy-oriented insights. This paper is a step in that trail.

Does gender affect visiting a world heritage site?

The city of Guimarães in Portugal is a place of strong symbolic and cultural significance, and the nomination of its historical center as a World Heritage Site in 2001 enhanced its tourism potential. This study presents the results of a survey conducted in 2010 and 2011 to capture the profile and motivations of tourists visiting Guimarães as a cultural tourism destination. The study addressed two main issues: whether males and females have similar or different preferences in choosing the city as their destination, and whether there are gender differences in the perception of the attributes of Guimarães. A better understanding of the gendered nature of the destination is a valuable cue for shaping products and services according to visitors’ preferences. The results suggest that both men and women are aware of the main elements responsible for the city’s World Heritage status. That the destination is a Heritage Site that also offers the opportunity to tour the region has a significant positive effect on male tourists’ choice of Guimarães. Regarding the perceived attributes of the city, results indicate minor gender differences with one exception: Women expressed more apprehension than men regarding the perceived security of the destination.

How does gender affect visiting a world heritage site?: the case study of Guimarães

To date few studies have been undertaken in Portugal dealing with the attitudes, motivations, and profile of tourists who visit World Heritage Sites. Also, few studies have dealt with destination image (e.g., Agapito, Mendes & Valle, 2010; Lopes, 2011). As far as it is known, none have approached the issue of gender differences in the choice of a Portuguese heritage destination. Since cultural tourism destinations need to differentiate themselves from each other, appropriate market segmentation must be based on a deep understanding of the customers’ motivations and preferences. Keeping in mind results from empirical literature (e.g., Silberberg, 1995; Beerli & Martin, 2004; Richards, 2004; Pérez, 2009; Sheng, Shen, & Chen, 2008), gender seems to be a possible approach to market segmentation, whether for Guimarães or for other cultural tourism destinations around the world. Located in the north-western region of Portugal, Guimarães is a city of strong symbolic and cultural significance, and the nomination of its historical centre as a World Heritage Site in 2001 enhanced its tourism potential. This study analyses the possible relation between gender and attitudes and motivations towards a World Heritage Site, such as Guimarães. Additionally, the empirical approach used in the study tries to capture differences in the perceived attributes of the city. Commonalities and distinctions within and between groups of tourists, by focusing on the specific characteristic of gender, were analysed. The study addressed two main questions: first, whether males and females have similar or different preferences in choosing the city as their destination; and, second, whether there are gender differences in the perception of the attributes of Guimarães. A better understanding of the gendered nature of the destination is a valuable cue for shaping products and services according to visitors’ preferences.

Does Gender Affect Visiting a World Heritage Site?

The city of Guimar˜aes in Portugal is a place of strong symbolic and cultural significance, and the nomination of its historical center as a World Heritage Site in 2001 enhanced its tourism potential. This study presents the results of a survey conducted in 2010 and 2011 to capture the profile and motivations of tourists visiting Guimar˜aes as a cultural tourism destination. The study addressed two main issues: whether males and females have similar or different preferences in choosing the city as their destination, and whether there are gender differences in the perception of the attributes of Guimar˜aes. A better understanding of the gendered nature of the destination is a valuable cue for shaping products and services according to visitors’ preferences. The results suggest that both men and women are aware of the main elements responsible for the city’s World Heritage status. That the destination is a Heritage Site that also offers the opportunity to tour the region has a significant positive effect on male tourists’ choice of Guimar˜aes. Regarding the perceived attributes of the city, results indicate minor gender differences with one exception: Women expressed more apprehension than men regarding the perceived security of the destination.

Chaos and crises in a model for cooperative hunting: A symbolic dynamics approach

In this work we investigate the population dynamics of cooperative hunting extending the McCann and Yodzis model for a three-species food chain system with a predator, a prey, and a resource species. The new model considers that a given fraction sigma of predators cooperates in prey's hunting, while the rest of the population 1-sigma hunts without cooperation. We use the theory of symbolic dynamics to study the topological entropy and the parameter space ordering of the kneading sequences associated with one-dimensional maps that reproduce significant aspects of the dynamics of the species under several degrees of cooperative hunting. Our model also allows us to investigate the so-called deterministic extinction via chaotic crisis and transient chaos in the framework of cooperative hunting. The symbolic sequences allow us to identify a critical boundary in the parameter spaces (K, C-0) and (K, sigma) which separates two scenarios: (i) all-species coexistence and (ii) predator's extinction via chaotic crisis. We show that the crisis value of the carrying capacity K-c decreases at increasing sigma, indicating that predator's populations with high degree of cooperative hunting are more sensitive to the chaotic crises. We also show that the control method of Dhamala and Lai [Phys. Rev. E 59, 1646 (1999)] can sustain the chaotic behavior after the crisis for systems with cooperative hunting. We finally analyze and quantify the inner structure of the target regions obtained with this control method for wider parameter values beyond the crisis, showing a power law dependence of the extinction transients on such critical parameters.

Symbolic Knowledge Extraction from Trained Neural Networks Governed by Lukasiewicz Logics

This work describes a methodology to extract symbolic rules from trained neural networks. In our approach, patterns on the network are codified using formulas on a Lukasiewicz logic. For this we take advantage of the fact that every connective in this multi-valued logic can be evaluated by a neuron in an artificial network having, by activation function the identity truncated to zero and one. This fact simplifies symbolic rule extraction and allows the easy injection of formulas into a network architecture. We trained this type of neural network using a back-propagation algorithm based on Levenderg-Marquardt algorithm, where in each learning iteration, we restricted the knowledge dissemination in the network structure. This makes the descriptive power of produced neural networks similar to the descriptive power of Lukasiewicz logic language, minimizing the information loss on the translation between connectionist and symbolic structures. To avoid redundance on the generated network, the method simplifies them in a pruning phase, using the "Optimal Brain Surgeon" algorithm. We tested this method on the task of finding the formula used on the generation of a given truth table. For real data tests, we selected the Mushrooms data set, available on the UCI Machine Learning Repository.

Literary translation and quality assessment analysis – its significance in translation training

This paper aims to highlight the role of translation quality assessment in translation training so as to develop students’ translation competence and skills to face translation problems. An analysis to assess literary translation quality is proposed before proceeding to discuss its pedagogical implementation.

Symbolic dynamics and renormalization of non-autonomous k periodic dynamical systems

The purpose of this paper was to introduce the symbolic formalism based on kneading theory, which allows us to study the renormalization of non-autonomous periodic dynamical systems.

Symbolic fractional dynamics

Fractional dynamics reveals long range memory properties of systems described by means of signals represented by real numbers. Alternatively, dynamical systems and signals can adopt a representation where states are quantified using a set of symbols. Such signals occur both in nature and in man made processes and have the potential of a aftermath as relevant as the classical counterpart. This paper explores the association of Fractional calculus and symbolic dynamics. The results are visualized by means of the multidimensional technique and reveal the association between the fractal dimension and one definition of fractional derivative.