Preventing Atomicity Violations with Contracts

Software developers are expected to protect concurrent accesses to shared regions of memory with some mutual exclusion primitive that ensures atomicity properties to a sequence of program statements. This approach prevents data races but may fail to provide all necessary correctness properties.The composition of correlated atomic operations without further synchronization may cause atomicity violations. Atomic violations may be avoided by grouping the correlated atomic regions in a single larger atomic scope. Concurrent programs are particularly prone to atomicity violations when they use services provided by third party packages or modules, since the programmer may fail to identify which services are correlated. In this paper we propose to use contracts for concurrency, where the developer of a module writes a set of contract terms that specify which methods are correlated and must be executed in the same atomic scope. These contracts are then used to verify the correctness of the main program with respect to the usage of the module(s). If a contract is well defined and complete, and the main program respects it, then the program is safe from atomicity violations with respect to that module. We also propose a static analysis based methodology to verify contracts for concurrency that we applied to some real-world software packages. The bug we found in Tomcat 6.0 was immediately acknowledged and corrected by its development team

Entrepreneurial artisan products as regional tourism competitiveness

Purpose – The purpose of this paper is to explore and analyse the role of entrepreneurial artisan products in regional tourism competitiveness. Design/methodology/approach – This study applies secondary data from different sources (Regional Directorate of Statistics of Madeira, the Madeira Institute of Wine, Embroideries and Handicrafts) covering a temporal period spanning the last 15 years (2001-2015). This deployed quantitative data analysis through an econometric approach with recourse to regression models and the Pearson’s correlation technique. Findings – According to the results, it is suggested that in terms of external support and funding, there should be a greater role and a boost in the number of projects carried out not only under the auspices of the European Union but also under the Autonomous Region of Madeira. Thus, participant companies may invest in greater business efficiency and entrepreneurship, in innovation, promotion and the internationalisation of their products, and thereby obtain greater overall regional competitiveness. Research limitations/implications – The generalisation of results remains to a certain extent limited, given the findings stem from only one particular region. The exclusive utilisation of secondary data may also undermine the robustness of the results obtained. Originality/value – The study provides empirical evidence that helps in identifying the role of artisan products within the capacity for regional tourism sector entrepreneurship and competitiveness. Furthermore, this also contributes to the knowledge of the scientific community particularly interested in artisan and cultural entrepreneurship and regional competitiveness in the tourism sector.info:eu-repo/semantics/publishedVersio

Mass-degenerate Higgs bosons at 125 GeV in the Two-Higgs-Doublet Model

The analysis of the Higgs boson data by the ATLAS and CMS Collaborations appears to exhibit an excess of h --> gamma\gamma events above the Standard Model (SM) expectations; whereas no significant excess is observed in h --> ZZ* --> {four lepton} events, albeit with large statistical uncertainty due to the small data sample. These results (assuming they persist with further data) could be explained by a pair of nearly mass-degenerate scalars, one of which is a SM-like Higgs boson and the other is a scalar with suppressed couplings to W+W- and ZZ. In the two Higgs doublet model, the observed \gamma\gamma and ZZ* --> {four lepton} data can be reproduced by an approximately degenerate CP-even (h) and CP-odd (A) Higgs boson for values of \sin(\beta-\alpha) near unity and 0.7 < \tan\beta < 1. An enhanced \gamma\gamma signal can also arise in cases where m_h ~ m_H, m_H ~ m_A, or m_h ~ m_H ~ m_A. Since the ZZ* --> {four lepton} signal derives primarily from a SM-like Higgs boson whereas the \gamma\gamma signal receives contributions from two (or more) nearly mass-degenerate states, one would expect a slightly different invariant mass peak in the ZZ* --> {four lepton} and \gamma\gamma channels. The phenomenological consequences of such models can be tested with additional Higgs data that will be collected at the LHC in the near future.Comment: 18 pages, 19 pdf figures, v2: references added, v3&v4: added refs and explanation

The role of entrepreneurial ecosystems in the SME internationalization

The Entrepreneurial Ecosystems (EE) articulate concepts from various streams of literature and are formed by multiple stakeholders and relate to different levels of analysis. Although the literature shows a growing relevance on the theme of EE, most studies reveal to be conceptual, and the existence of empirical studies with quantitative methodologies is still scarce. This study attempts to contribute to filling this gap by developing a dynamic model of EE and its impact on the small and medium-sized enterprises (SME) international performance by aggregating different levels of analysis. Based on a sample of 120 SMEs, the results suggest that macro (agents) and meso (different partners) level variables positively impact international performance. We also find that technology transfer has a negative moderating effect on the meso level relationship of EE with digital performance. Our study also contributes to a greater understanding of the Entrepreneurial Ecosystems, its internationalization and the digital performance effect.info:eu-repo/semantics/publishedVersio

Tourist events and satisfaction: a product of regional tourism competitiveness

Purpose – This study aims to analyze the contribution of tourist event and satisfaction with tourism events as a product of regional tourism competitiveness, as well as evaluate factors of competitiveness. Design/methodology/approach – The research followed a quantitative methodology by conducting a questionnaire on the four largest tourist events in Madeira (Carnival, Flower Festival, Atlantic Festival and Wine Festival), an insular island located in Portugal. Findings – The sample consisted of 2,262 tourists surveyed during the year 2017 and structural equation models were used as the statistical method. Results showed that satisfaction is reflected in the client’s loyalty to the choice of a tourist destination and also contributes directly and indirectly to the regional tourist competitiveness. Originality/value – This study contributes to the valorization of local and regional events, perceived by the level of satisfaction and loyalty of tourists, as products of regional competitiveness of a tourist destination.info:eu-repo/semantics/publishedVersio

Comparing Single-Item and Multi-Item Trust Scales: Insights for Assessing Trust in Project Leaders

Funding: This research was funded by Instituto Politécnico de Setúbal. Institutional Review Board Statement: Ethical review and approval were waived for this study. Brazilian Comitê de Ética de Pesquisa (CEP), CNS/466/12, indicates ethical approval is not required for this type of study.The purpose of this research is to provide researchers and leaders with a reliable and up-to- date comparison between a single-item and a multi-item trust scale, enabling effective assessment of team members’ trust in their leaders. The aim of the study is to investigate whether a single-question scale is as reliable as a multi-item questionnaire in measuring trust. An additional goal is to provide researchers with insights and conditions for effectively using single or multiple measures to assess trust in leaders, considering factors like reliability and effectiveness. After conducting a compre- hensive literature review, data were collected from 101 project members in Brazil using a survey methodology. The respondents were asked to provide feedback regarding their leaders, specifically project managers, and factor analysis was then employed to test the single-item and multi-item measures of trust. The advantages and disadvantages of each approach are discussed. The findings of our study demonstrate that both single-item and multi-item scales of trust should be utilized to gain a more comprehensive understanding of the trust construct. Single-item questionnaires can reduce survey length, improve respondent friendliness, and increase participant willingness. On the other hand, multi-item questionnaires enable researchers to analyze latent variables that contribute to an overall variable, but they cannot isolate data for each of those constructs. The results show that both measures are reliable, providing researchers and professionals with insights into the benefits and drawbacks associated with each method. Consequently, this research equips researchers and project professionals with valuable information for selecting the appropriate measurement tool.info:eu-repo/semantics/publishedVersio

The epidemiology ontology: an ontology for the semantic annotation of epidemiological resources

BACKGROUND: Epidemiology is a data-intensive and multi-disciplinary subject, where data integration, curation and sharing are becoming increasingly relevant, given its global context and time constraints. The semantic annotation of epidemiology resources is a cornerstone to effectively support such activities. Although several ontologies cover some of the subdomains of epidemiology, we identified a lack of semantic resources for epidemiology-specific terms. This paper addresses this need by proposing the Epidemiology Ontology (EPO) and by describing its integration with other related ontologies into a semantic enabled platform for sharing epidemiology resources. RESULTS: The EPO follows the OBO Foundry guidelines and uses the Basic Formal Ontology (BFO) as an upper ontology. The first version of EPO models several epidemiology and demography parameters as well as transmission of infection processes, participants and related procedures. It currently has nearly 200 classes and is designed to support the semantic annotation of epidemiology resources and data integration, as well as information retrieval and knowledge discovery activities. CONCLUSIONS: EPO is under active development and is freely available at https://code.google.com/p/epidemiology-ontology/. We believe that the annotation of epidemiology resources with EPO will help researchers to gain a better understanding of global epidemiological events by enhancing data integration and sharing

Prevailing theoretical approaches predicting sustainable business models: a systematic review

Purpose: This study aims to map scientific publications, intellectual structure and research trends in the sustainable business model (SBM) field. Specifically, it attempts to (1) identify the fundamental contributions of research in this area of knowledge; and (2) determine the research lines that constitute the most prominent intellectual structure. We leverage these insights to formulate and propose a future research agenda for SBM. Design/methodology/approach: The authors made recourse to the bibliometric, co-citation and cluster analysis techniques. To evaluate potential patterns among articles, we analysed how articles are jointly cited. We further applied hierarchical cluster analysis to the articles and used co-citation analysis to group the interrelated articles into distinct sets. Findings: The results enable the identification and classification of the prevailing theoretical foci in the domain of SBM: (1) SBM implementation; (2) SBM challenges; (3) institutional SBM; (4) circular SBM; and (5) emerging SBM. Originality/value: This study identifies, explores, analyses and summarises the main theoretical approaches and themes surrounding SBM research to date, contributing to deepening the literature by identifying the priority areas concerning sustainable business models and encouraging future research of an internationally excellent standard.info:eu-repo/semantics/acceptedVersio

Exopolysaccharide production by Helicobacter pylori

Helicobacter pylori is a widespread Gram-negative bacterium that infects the stomach of humans leading to the onset of several gastric disorders, such as, gastritis, gastric ulcers, and cancers. Studies from developing countries with low socioeconomic status and poor management of the drinking water suggest that it may serve as an environmental reservoir of H. pylori and therefore contribute to human infection. It has been reported that H. pylori has the ability to form microbial consortia embedded by a highly hydrated exopolysaccharidic matrix (biofilms) on surfaces exposed to water. The enhanced protection provided to microbial cells by the exopolysaccharides (EPS) brings added concerns about the possibility of H. pylori being transmitted through drinking water. H. pylori EPS as been reported to be composed mainly by Gal:Glc:GlcN in a proportion of 1.0:2.1:7.0, respectively (Stark et al., 1999). The present work brings about microscopical evidences of the capability of H. pilory to form free swimming bacterial aggregates and biofilms when submitted to nutrient depletion and hydrodynamic stress. Evidences that H. pylori aggregation is an exopolysaccharidic mediated phenomena both in planktonic and sessile states are also showed. Ethanol fractioning of the material recovered from these aggregates revealed an EPS composed of Gal:Glc:GlcN in a proportion of 1.0:0.4:1.6 respectively. A further structural detail about this EPS is under progress