A multilayered graph-based framework to explore behavioural phenomena in social media conversations

Objective Social media is part of current health communications. This research aims to delve into the effects of social contagion, biased assimilation, and homophily in building and changing health opinions on social media. Materials and Methods Conversations about COVID-19 vaccination on English and Spanish Twitter are the case studies. A new multilayered graph-based framework supports the integrated analysis of content similarity within and across posts, users, and conversations to interpret contrasting and confluent user stances. Deep learning models are applied to infer stance. Graph centrality and homophily scores support the interpretation of information reproduction. Results The results show that semantically related English posts tend to present a similar stance about COVID-19 vaccination (rstance=0.51) whereas Spanish posts are more heterophilic (rstance=0.38). Neither case showed evidence of homophily regarding user influence or vaccine hashtags. Graph filters for Pfizer and Astrazeneca with a similarity threshold of 0.85 show stance homophily in English scenarios (i.e. rstance=0.45 and rstance=0.58, respectively) and small homophily in Spanish scenarios (i.e. r=0.12 and r=0.3, respectively). Highly connected users are a minority and are not socially influential. Spanish conversations showed stance homophily, i.e. most of the connected conversations promote vaccination (rstance=0.42), whereas English conversations are more likely to offer contrasting stances. Conclusion The methodology proposed for quantifying the impact of natural and intentional social behaviours in health information reproduction can be applied to any of the main social platforms and any given topic of conversation. Its effectiveness was demonstrated by two case studies describing English and Spanish demographic and sociocultural scenarios.This study was supported by MCIN/AEI/ 10.13039/501100011033 under the scope of the CURMIS4th project (Grant PID2020–113673RB-I00), the Consellería de Educación, Universidades e Formación Profesional (Xunta de Galicia) under the scope of the strategic funding of ED431C2018/55-GRC Competitive Reference Group, the “Centro singular de investigación de Galicia” (accreditation 2019–2022), and the Portuguese Foundation for Science and Technology(FCT) under the scope of the strategic funding of UIDB/04469/2020 unit. SING group thanks CITI (Centro de Investigación, Transferencia e Innovación) from the University of Vigo for hosting its IT infrastructure. Funding for open access charge: Universidade de Vigo/CISUG.info:eu-repo/semantics/publishedVersio

Insights into Pseudomonas aeruginosa and Candida albicans consortia challenged by antimicrobials

Ventilator associated pneumonia (VAP), an usual nosocomial infection in the intensive care units and the most common in mechanically ventilated patients, is a serious problem due to high mortality and morbidity rates associated. The presence of the endotracheal tube is the principal risk factor for developing VAP because its surface is prone to microbial adhesion and the formation of biofilms, deserving thus high attention in clinical settings. Cell-to-cell communication is an important mechanism of interaction between VAP microorganisms, being involved in the process known as quorum-sensing (QS) that regulate the expression of virulence. To evaluate bacteria fungi cross-talk in co-infection, the biofilm-forming ability of Pseudomonas aeruginosa and Candida albicans, individually or jointly, before and after antibiotic and antifungal co-treatment was tested. Biofilms were characterized in terms of total mass and cell viability. Results showed that no antimicrobial combination was successful in the binary biofilms eradication. In some cases, the tolerance of the polymicrobial consortia was higher than that of single biofilms, highlighting that P. aeruginosa and C. albicans established synergistic relationships. To gain knowledge helping to explain those interactions, a quantitative real-time PCR approach was followed to inspect the expression profiles of some cell-cell communication genes involved in biofilm resistance. To overcome the tolerance issues, new antimicrobial combinatorial approaches using QS-inhibitors are being tested. Some combinations involving chlorogenic acid and ciprofloxacin displayed promising anti-biofilm potential

Agent-based model of diffusion of N-acyl homoserine lactones in a multicellular environment of Pseudomonas aeruginosa and Candida albicans

Experimental incapacity to track microbemicrobe interactions in structures like biofilms, and the complexity inherent to the mathematical modelling of those interactions, raises the need for feasible, alternative modelling approaches. This work proposes an agent-based representation of the diffusion of N-acyl homoserine lactones (AHL) in a multicellular environment formed by Pseudomonas aeruginosa and Candida albicans. Depending on the spatial location, C. albicans cells were variably exposed to AHLs, an observation that might help explain why phenotypic switching of individual cells in biofilms occurred at different time points. The simulation and algebraic results were similar for simpler scenarios, although some statistical differences could be observed (p<0.05). The model was also successfully applied to a more complex scenario representing a small multicellular environment containing C. albicans and P. aeruginosa cells encased in a 3-D matrix. Further development of this model may help create a predictive tool to depict biofilm heterogeneity at the single-cell level.This work has been funded by a Research Grant 2014 by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) to AL; the Portuguese Foundation for Science and Technology (FCT) [grant numbers UID/ BIO/04469/2013, UID/EQU/00511/2013] units and COMPETE 2020 [grant numbers POCI-01-0145-FEDER-006684, POCI-01-0145-FEDER-006939]; North Portugal Regional Operational Programme (NORTE 2020) [grant number NORTE‐01‐0145‐FEDER‐000005 – LEPABE-2-ECO-INNOVATION] under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio

Las proteínas extracelulares de Lactobacillus acidophilus DSM 20079t como potenciales moduladores de la respuesta inmune en enfermedades inflamatorias crónicas

El uso de probióticos o compuestos bacterianos se ha propuesto como un mecanismo para modular la respuesta inmune del hospedador y remodelar el microbioma humano. Sin embargo, actualmente existe una falta de información sobre las vías moleculares inducidas por las bacterias probióticas, o sobre la interacción entre los probióticos y el sistema inmunológico. Lactobacillus es un género del filo Firmicutes que incluye cepas probióticas y representativas de la microbiota gastrointestinal humana. Estudios independientes han demostrado las propiedades antiinflamatorias de diferentes cepas de Lactobacillus, aunque estamos lejos de comprender la interacción molecular subyacente. En este trabajo, demostramos que una administración diaria de 5e10 células viables de Lactobacillus acidophilus DSM 20079T (DSM20079) a lechones sanos produjo un aumento plasmático de la interleucina antinflamatoria IL10, disminuyendo, a su vez, la interleucina IL12 y la ratio proinflamatorio IL12 + TNF / IL10. Además, las células mononucleares de sangre preriféricas (PBMCs) extraídas de estos lechones se volvieron menos reactivas contra el lipopolisacárido de Escherichia coli (LPS) y la fitohemaglutinina de Phaseolus vulgaris (PHA), cuando se ven afectadas por la cepa DSM20079. Se identificó la fracción proteica extracelular de DSM20079 como la responsable de esta modulación. El efecto tolerogénico ejercido por las proteínas extracelulares de esta cepa sugiere su uso potencial como coadyuvante para aplicaciones terapéuticas dirigidas a enfermedades inflamatorias crónicas.Este trabajo fue respaldado por el "Programa Estatal de Investigación, Desarrollo e Inovación Orientada a los Retos de la Sociedad" (AGL2016-78311-R); la Asociación Española Contra el Cáncer ("Obtención de péptidos bioactivos contra el Cáncer Colo-Rectal a partir de secuencias genéticas de microbiomas intestinales", PS-2016).info:eu-repo/semantics/publishedVersio

Applying clickstream data mining to real-time Web crawler detection and containment using ClickTips platform

Web crawler uncontrolled widespread has led to undesired situations of server overload and contents misuse. Most programs still have legitimate and useful goals, but standard detection heuristics have not evolved along with Web crawling technology and are now unable to identify most of today's programs. In this paper, we propose an integrated approach to the problem that ensures the generation of up-to-date decision models, targeting both monitoring and clickstream differentiation. The ClickTips platform sustains Web crawler detection and containment mechanisms and its data webhousing system is responsible for clickstream processing and further data mining. Web crawler detection and monitoring helps preserving Web server performance and Web site privacy and clickstream differentiated analysis provides focused report and interpretation of navigational patterns. The generation of up-to-date detection models is based on clickstream data mining and targets riot only well-known Web crawlers, but also camouflaging and previously unknown programs. Experiments with different real-world Web sites are optimistic, proving that the approach is not only feasible but also adequate.The work of Anlia Loureno was supported by a grant from Fundao para a Cincia e Tecnologia - FRH/BD/8242/2002.info:eu-repo/semantics/publishedVersio

Web crawler profiling and containment through navigation pattern mining

Web profiles may support the analysis of Web site popularity as well as the detection of unwanted and illegitimate activities such as fraud. Yet, profiling techniques often fail to account for different usage, processing regular sessions, crawler sessions and proxy sessions in a similar way. This paper proposes an integrated approach to Web crawler profiling and containment. A data Webhousing embracing standard crawler detection techniques supplies the profiles to be further analysed through navigation pattern mining. The ability to adapt crawler identification to particular Web scenarios, the incremental analysis of navigation patterns, and the capacity of monitoring server performance and preventing crawler-related hazards are considered main strengths of this approach. Experiments over six-month Web server logs of a non-commercial Web site evidence the benefits of focused Web profiling and, in particular, of this approach.(undefined)info:eu-repo/semantics/publishedVersio

Catching web crawlers in the act

This paper recommends a new approach to the detection and containment of Web crawler traverses based on clickstream data mining. Timely detection prevents crawler abusive consumption of Web server resources and eventual site contents privacy or copyrights violation. Clickstream data differentiation ensures focused usage analysis, valuable both for regular users and crawler profiling. Our platform, named ClickTips, sustains a site-specific, updatable detection model that tags Web crawler traverses based on incremental Web session inspection and a decision model that assesses eventual containment. The goal is to deliver a model flexible enough to keep up with crawling continuous evolving and that is capable of detecting crawler presence as soon as possible. We use a real-world Web site case study as a support for process description, as well as, to evaluate the accuracy of the obtained classification models and their ability for discovering previously unknown Web crawlers.- (undefined

Signature based credentials, an alternative method for validating student access in eLearning systems

e-Learning systems are today one of the most used tools in student’s life. Every time a student uses an e-Learning system he initiates a pre-defined, and often implicit, set of clicks, which somewhat characterizes his interests. The navigation habits of students can be revealed easily through a conventional usage profiling process. In most cases, these profiles are used to optimize the organization of e-Learning systems, to tune its services, or simply to reallocate resources and services in better access places. In this paper, we analyse student profiles with a different, less- conventional goal: to identify improper and anomalous accesses to e-Learning systems requiring user credentials (login and password)

Agent-based knowledge extraction services inside enterprise data warehousing systems environments

During their lifetimes, enterprises have been storing and maintaining huge amounts of business and operational information. As time passed their information repositories grown almost exponentially and they have typically got "drown" in data. So, they felt the urge for more suitable systems, capable of gathering, treating and storing this data avalanche in appropriated manners. Therefore, it is necessary to conceive and implant adequate analytical systems, capable of dealing with this huge potential of information in the best way, and providing new knowledge about the activities of organizations. Taking these real scenarios into account, we designed and developed a multi-agent system specially conceived to support knowledge extraction processes over data warehousing systems, covering the definition and preparation of the data repositories to be mined, till the visualization and manipulation of the results