Bots increase exposure to negative and inflammatory content in online social systems

Societies are complex systems which tend to polarize into sub-groups of individuals with dramatically opposite perspectives. This phenomenon is reflected -- and often amplified -- in online social networks where, however, humans are no more the only players, and co-exist alongside with social bots, i.e., software-controlled accounts. Analyzing large-scale social data collected during the Catalan referendum for independence on October 1, 2017, consisting of nearly 4 millions Twitter posts generated by almost 1 million users, we identify the two polarized groups of Independentists and Constitutionalists and quantify the structural and emotional roles played by social bots. We show that bots act from peripheral areas of the social system to target influential humans of both groups, bombarding Independentists with violent contents, increasing their exposure to negative and inflammatory narratives and exacerbating social conflict online. Our findings stress the importance of developing countermeasures to unmask these forms of automated social manipulation.Comment: 8 pages, 5 figure

XML Matchers: approaches and challenges

Schema Matching, i.e. the process of discovering semantic correspondences between concepts adopted in different data source schemas, has been a key topic in Database and Artificial Intelligence research areas for many years. In the past, it was largely investigated especially for classical database models (e.g., E/R schemas, relational databases, etc.). However, in the latest years, the widespread adoption of XML in the most disparate application fields pushed a growing number of researchers to design XML-specific Schema Matching approaches, called XML Matchers, aiming at finding semantic matchings between concepts defined in DTDs and XSDs. XML Matchers do not just take well-known techniques originally designed for other data models and apply them on DTDs/XSDs, but they exploit specific XML features (e.g., the hierarchical structure of a DTD/XSD) to improve the performance of the Schema Matching process. The design of XML Matchers is currently a well-established research area. The main goal of this paper is to provide a detailed description and classification of XML Matchers. We first describe to what extent the specificities of DTDs/XSDs impact on the Schema Matching task. Then we introduce a template, called XML Matcher Template, that describes the main components of an XML Matcher, their role and behavior. We illustrate how each of these components has been implemented in some popular XML Matchers. We consider our XML Matcher Template as the baseline for objectively comparing approaches that, at first glance, might appear as unrelated. The introduction of this template can be useful in the design of future XML Matchers. Finally, we analyze commercial tools implementing XML Matchers and introduce two challenging issues strictly related to this topic, namely XML source clustering and uncertainty management in XML Matchers.Comment: 34 pages, 8 tables, 7 figure

Effective Retrieval of Resources in Folksonomies Using a New Tag Similarity Measure

Social (or folksonomic) tagging has become a very popular way to describe content within Web 2.0 websites. However, as tags are informally defined, continually changing, and ungoverned, it has often been criticised for lowering, rather than increasing, the efficiency of searching. To address this issue, a variety of approaches have been proposed that recommend users what tags to use, both when labeling and when looking for resources. These techniques work well in dense folksonomies, but they fail to do so when tag usage exhibits a power law distribution, as it often happens in real-life folksonomies. To tackle this issue, we propose an approach that induces the creation of a dense folksonomy, in a fully automatic and transparent way: when users label resources, an innovative tag similarity metric is deployed, so to enrich the chosen tag set with related tags already present in the folksonomy. The proposed metric, which represents the core of our approach, is based on the mutual reinforcement principle. Our experimental evaluation proves that the accuracy and coverage of searches guaranteed by our metric are higher than those achieved by applying classical metrics.Comment: 6 pages, 2 figures, CIKM 2011: 20th ACM Conference on Information and Knowledge Managemen

potential of the virtual blade model in the analysis of wind turbine wakes using wind tunnel blind tests

Abstract The present research frontier on wind turbine wake analysis is leading to a massive use of large-eddy simulations to completely solve the flow field surrounding the rotors; on the other hand, there is still room for lower-fidelity models with a more affordable computational cost to be used in extended optimization analyses, e.g. for a park layout definition. In this study, a customized version of the Virtual Blade Model (VBM) for ANSYS ® FLUENT ® is presented. The model allows a hybrid solution of the flow, in which the surrounding environment is simulated through a conventional RANS approach, while blades are replaced by a body force, calculated by a simplified version of the Blade Element Theory. The potential of the newly-customized VBM was evaluated by applying it to the famous NOWITECH-NORCOWE blind tests for horizontal axis wind turbines. Several test cases were analyzed and discussed including: 1) a single turbine; 2) an array of two turbines with one rotor working in the wake of the other one; 3) an array of two staggered rotors; 4) several configurations of rotors working in yawed-flow. The study proves that the VBM model can represent a valuable tool for the analysis of wind turbines wakes and of their interaction with near rotors

Plasma and Red Blood Cells Concentration Profiles of Ktamine after Single Intravenous Administration in an Anaesthetic Protocol in Horses

The aim of this study was to describe the concentration profile of ketamine in plasma and red blood cells following an intravenous (IV) bolus in the horse. Ten healthy standardbred horses (two males and height females) 7.7 ± 4.6 (mean value ± SD) years old and weighting 380 ± 21 kg (mean value ± SD) were recruited. The horses were premedicated with acepromazine (0.04 mg·kg-1·IV). Fifteen minutes later they received romifidine (0.08 mg·kg-1·IV), and 5 minutes after they were administered midazolam (0.06 mg·kg-1·IV). Immediately, anaesthesia was induced by ketamine (2.2 mg·kg-1·IV). Venous blood samples were collected at scheduled time points. Plasma and red blood cells (RBCs) concentration of ketamine was assayed using a high performance liquid chromatographic method (HPLC/UV-DAD). The high mean recovery rates, the high sensitivity, the good linearity, suggest a clinical applicability of the analytical method. A bicompartmental model resulted as the most appropriate to describe the ketamine concentration—time profile for both plasma and RBCs. The fitted regression line between ketamine plasma concentrations and RBC concentrations supports the good correlation between ketamine concentrations in plasma and in RBCs. The kinetic parameters of ketamine calculated for RBC are equal or very similar to the plasma ones. The study confirms the kinetic behaviour of ketamine used in the horse as anaesthetic inducers in routine surgery. Finally, the bicompartmental model well describes the ketamine profile also in RBCs, that it is very close to the plasma profile, underlining the great importance of RBCs as blood subcompartment

“Spontaneous” ping-pong fracture in newborns: case report and review of the literature

“Ping-pong” fractures (PPF) are depressed skull fractures typical of newborns. PPF usually result from head injury and, rarely, may cause severe long-term neurological sequelae. The management of PPF is still controversial. The goal of this paper is to present a case of “spontaneous” ping-pong fracture and to review the pertinent literature of the last 20 years. We report on a newborn who presented with a “spontaneous” parietal depressed skull fracture at birth. Preoperative computed tomography (CT) scan confirmed the PPF and excluded brain injuries. Neurosurgical intervention was performed on day 3 with immediate lifting of the fracture; the postoperative course was uneventful. During the last 20 years, 22 cases of “spontaneous ping-pong” fractures in newborn have been reported, with different clinical pictures and management but, generally, with a good outcome. “Ping-pong” fractures can occur in uneventful pregnancies and after uncomplicated vaginal or cesarean deliveries. CT scan, with low-dose protocol for infants, is the gold standard examination to evaluate the fracture and any associated brain lesions. Treatment is selected according to fracture characteristics

Architecture: experience and education for children

Ponència presentada a: Session 3: Educación y arquitectura: fundamentos teóricos / Education and architecture: theoretical foundation

Architecture: experience and education for children

Ponència presentada a: Session 3: Educación y arquitectura: fundamentos teóricos / Education and architecture: theoretical foundation

Metformin-related lactic acidosis: is it a myth or an underestimated reality?

AbstractMetformin, belonging to a class of drugs called biguanides, is the recommended first-line treatment for overweight patients with type 2 diabetes mellitus. It has multiple mechanisms of action, such as reduction of gluconeogenesis, increases peripheral uptake of glucose, and decreases fatty acid oxidation. However, a potential serious complication, defined metformin-associated lactic acidosis (MALA), is related to increased plasma lactate levels, linked to an elevated plasma metformin concentrations and/or a coexistent condition altering lactate production or clearance. The mortality rate for MALA approaches 50% and metformin has been contraindicated in moderate and severe renal impairment, to minimize its potential toxic levels. Nevertheless, metformin prescription or administration, despite the presence of contraindications or precipitating factors for MALA, was a common topic highlighted in all reviewed papers. Routine assessment of metformin plasma concentration is not easily available in all l..