struc2vec: Learning Node Representations from Structural Identity

Structural identity is a concept of symmetry in which network nodes are identified according to the network structure and their relationship to other nodes. Structural identity has been studied in theory and practice over the past decades, but only recently has it been addressed with representational learning techniques. This work presents struc2vec, a novel and flexible framework for learning latent representations for the structural identity of nodes. struc2vec uses a hierarchy to measure node similarity at different scales, and constructs a multilayer graph to encode structural similarities and generate structural context for nodes. Numerical experiments indicate that state-of-the-art techniques for learning node representations fail in capturing stronger notions of structural identity, while struc2vec exhibits much superior performance in this task, as it overcomes limitations of prior approaches. As a consequence, numerical experiments indicate that struc2vec improves performance on classification tasks that depend more on structural identity.Comment: 10 pages, KDD2017, Research Trac

Understanding and Detecting Hateful Content using Contrastive Learning

The spread of hate speech and hateful imagery on the Web is a significant problem that needs to be mitigated to improve our Web experience. This work contributes to research efforts to detect and understand hateful content on the Web by undertaking a multimodal analysis of Antisemitism and Islamophobia on 4chan's /pol/ using OpenAI's CLIP. This large pre-trained model uses the Contrastive Learning paradigm. We devise a methodology to identify a set of Antisemitic and Islamophobic hateful textual phrases using Google's Perspective API and manual annotations. Then, we use OpenAI's CLIP to identify images that are highly similar to our Antisemitic/Islamophobic textual phrases. By running our methodology on a dataset that includes 66M posts and 5.8M images shared on 4chan's /pol/ for 18 months, we detect 573,513 posts containing 92K Antisemitic/Islamophobic images and 246K posts that include 420 hateful phrases. Among other things, we find that we can use OpenAI's CLIP model to detect hateful content with an accuracy score of 0.84 (F1 score = 0.58). Also, we find that Antisemitic/Islamophobic imagery is shared in 2x more posts on 4chan's /pol/ compared to Antisemitic/Islamophobic textual phrases, highlighting the need to design more tools for detecting hateful imagery. Finally, we make publicly available a dataset of 420 Antisemitic/Islamophobic phrases and 92K images that can assist researchers in further understanding Antisemitism/Islamophobia and developing more accurate hate speech detection models

Synthesis, physicochemical and photophysical characterization of 4-(1-Pyrenyl)-Butyl-α-d-mannopyranoside

Indexación: Web of Science; Scopus; Scielo.Glycolipids are biomolecules composed of a lipid chain (lipophilic) and a monosaccharide or oligosaccharide as hydrophilic group. Their chemical structure and biological role make them undoubtedly good candidates for a large and continuously growing number of biotechnological applications. Mannose is a carbohydrate present on membrane glycolipids of a wide number of pathogenic microorganisms (bacteria, fungi, protozoa, and viruses) and specifically recognized by several lectins. We synthesized a mannose derivative linked through a short methylene chain to a pyrene moiety which behaves as a surfactant, able to aggregate, and retains the photophysical properties of pyrene: showing comparable absorption and emission spectra, having lower fluorescence quantum yield and the ability to form excimer, and finally the ability to produce O-2((1)Delta(g)) with high quantum yields. Thus, this novel molecule would open future applications for detection (fluorescence) or inactivation (singlet oxygen) of bacterial pathogens, viruses, tumor cells, or particular cells.http://ref.scielo.org/pcn4d

Detection of Catalase Activity by Polyacrylamide Gel Electrophoresis (PAGE) in Cell Extracts from Pseudomonas aeruginosa

Bacteria in nature and as pathogens commonly face oxidative stress which causes damage to proteins, lipids and DNA. This damage is produced by the action of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), singlet oxygen, superoxide anion and hydroxyl radical. ROS are generated by antimicrobials, environmental factors (e.g., ultraviolet radiation, osmotic stress), aerobic respiration, and host phagocytes during infective processes. Pseudomonas aeruginosa, a versatile bacterium, is a prevalent opportunistic human pathogen which possesses several defense strategies against ROS. Among them, two catalases (KatA and KatB) have been well characterized by their role on the defense against multiple types of stress. In this protocol, KatA and KatB activities are detected by polyacrylamide gel electrophoresis (PAGE). It is also suggested that the detection of KatB is elusive.Fil: Pezzoni, Magdalena. Comisión Nacional de Energía Atómica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pizarro, R. A.. Comisión Nacional de Energía Atómica; ArgentinaFil: Costa, C. S.. Comisión Nacional de Energía Atómica; Argentin

The role peer responses to adolescent expression of emotions plays in their emotion regulation : A systematic literature review

Introduction Peer responses to adolescents’ emotional expressions (PREE), are thought to influence the continued development of emotion regulation (ER). Unsupportive (e.g., dismissive) PREE, for example, are expected to be associated with greater maladaptive ER. Poor ER is known to place adolescents at risk of psychopathology. The aim of this systematic review was to collate and synthesize the emerging evidence exploring the role that peer emotion socialization, specifically PREE, plays in adolescent ER and identify future directions. Methods In adherence with PRISMA guidelines, PsychINFO, Medline Complete, CINAHL Complete, Scopus and Web of Science were searched on April 20th, 2021, May 28th, 2022, and April 12th, 2023 for English language reports published after 1998. To be included, studies needed to report on PREE and its relation to adolescent ER. Results A total of eight studies, one qualitative and seven quantitative, met inclusion criteria and had a combined N of 785 participants (aged 10–18 years). Studies were primarily undertaken in the US and mostly included males and females, with one study only including female participants. Conclusions Although only eight studies were identified, the review identified preliminary evidence for an association between PREE and ER in adolescents. This association appeared to vary depending on adolescent gender, age, the closeness of the friendship and the PREE. Several limitations were identified, and suggestions are made for future research in this emerging area

Urban Green Spaces, Greenness Exposure and Species Richness in Residential Environments and Relations with Physical Activity and BMI in Portuguese Adolescents

Environmental factors play an important role in obesity-related behaviors. Evidence indicates significant associations between weight and urban green spaces in adults, but it is not clear whether this relationship applies to adolescents. Therefore, our aim was to determine the associations between urban green spaces, greenness exposure and species richness in residential environments with physical activity and body mass index. Sixty-two adolescents between 12 and 18 years of age answered a self-administered questionnaire, providing information on height, weight, age, sex and home address. Data on socioeconomic deprivation were obtained from the European Index of Deprivation for Small Portuguese Areas. Physical activity levels were assessed using accelerometers. Urban green space counts and the normalized difference vegetation index values were measured using buffers along the roads with distances of 300, 500, 1000 and 1500 m from each participant’s residence. To quantify the species richness, the species richness index was used. Linear regression models were fitted to analyze whether urban green spaces, exposure to green spaces and species richness counts for each distance were associated with physical activity and self-reported body mass index. We did not find significant associations between the independent variables and the probability of overweight or obesity. The relationship between environmental variables, adolescents’ physical activity and body weight seems to be complex and further studies may contribute to better understanding of the topic.This research was funded by FEDER through the Operational Program for Competitiveness and Internationalization and received national funding from the Foundation for Science and Technology—FCT (Portuguese Ministry of Science, Technology and Higher Education), under the Research Center in Physical Activity, Health and Leisure (CIAFEL) (UIDB/00617/2020) and also under the Epidemiology Research Unit (EPIUnit)—Institute of Public Health of the University of Porto (info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB/04750/2020/PT). Ana Isabel Ribeiro was supported by national funds through FCT, under the ‘Stimulus of Scientific Employment—Individual Support’ program within the contract info:eu-repo/grantAgreement/FCT/CEEC IND 2018/CEECIND/02386/2018/CP1538/CT0001/PT

Trabajo Social escolar, ciudadanía y educación: Una reflexión pertinente

School social work confronts a dilemma rooted in the deterioration of the public school system. Henee, this dilemma calls for the need to evaluate the paradigms of the school social work interventions. In the Department of Education's official memo for school social work # 16-2004-2005, the language used is ambiguous and superficial. It is based on a positivism discourse about what the intervention should be, thus limiting what the social work discipline can bring to the educational process. This discourse in its practice focus the attention on individual casework and group work, thus limiting what the community work method could do to the educational process. The attention of school social work to the educational process of the social construction of citizenship, nurturing a participatory leadership among students, family and community is almost non-existence. The errors in the decentralization and the invisibility of the educative autonomy constitute barriers for the construction of a new grammar in the school social work. I suggest that the school social work should focus its intervention from a new perspective. It should be focused on a new relationship with all the members that constitutes the school community and within its macro structural context, based in the social construction of an educational citizenship and taking into consideration the ideas about educational subjects.El trabajo social escolar enfrenta el dilema de evaluar los paradigmas de la intervención social a raíz del deterioro de la educación pública. En la Carta Circular de Trabajo Social 16-2004-2005 del Departamento de Educación, predomina un discurso ambiguo y superficial, basado en enfoques positivistas de intervención, los cuales limitan la aportación que esta disciplina puede hacer al proceso educativo. En su praxis se privilegia la atención a casos en su modalidad individual o grupal, con poca atención al método comunitario. La atención del trabajo social a procesos de construcción de ciudadanía educativa, a la formación de liderazgo participativo de estudiantes, a familias y comunidad son estrategias lejanas en la mayoría de las escuelas. Los desaciertos en la descentralización y la invisibilidad de la autonomía educativa, constituyen barreras para la construcción de una nueva gramática en el trabajo social escolar. Sugiero reenfocar la intervención social desde una nueva relación con los demás componentes de la comunidad escolar y con su contexto macroestructural. Esta debe estar basada en la construcción de una ciudadanía educativa y en la revisión de las ideas sobre quiénes son los sujetos educativos

Critical Strain Region Evaluation of Self-Assembled Semiconductor Quantum Dots

A novel peak finding method to map the strain from high resolution transmission electron micrographs, known as the Peak Pairs method, has been applied to In(Ga) As/AlGaAs quantum dot (QD) samples, which present stacking faults emerging from the QD edges. Moreover, strain distribution has been simulated by the finite element method applying the elastic theory on a 3D QD model. The agreement existing between determined and simulated strain values reveals that these techniques are consistent enough to qualitatively characterize the strain distribution of nanostructured materials. The correct application of both methods allows the localization of critical strain zones in semiconductor QDs, predicting the nucleation of defects, and being a very useful tool for the design of semiconductor device

Regulation of surface architecture by symbiotic bacteria mediates host colonization

Microbes occupy countless ecological niches in nature. Sometimes these environments may be on or within another organism, as is the case in both microbial infections and symbiosis of mammals. Unlike pathogens that establish opportunistic infections, hundreds of human commensal bacterial species establish a lifelong cohabitation with their hosts. Although many virulence factors of infectious bacteria have been described, the molecular mechanisms used during beneficial host–symbiont colonization remain almost entirely unknown. The novel identification of multiple surface polysaccharides in the important human symbiont Bacteroides fragilis raised the critical question of how these molecules contribute to commensalism. To understand the function of the bacterial capsule during symbiotic colonization of mammals, we generated B. fragilis strains deleted in the global regulator of polysaccharide expression and isolated mutants with defects in capsule expression. Surprisingly, attempts to completely eliminate capsule production are not tolerated by the microorganism, which displays growth deficits and subsequent reversion to express capsular polysaccharides. We identify an alternative pathway by which B. fragilis is able to reestablish capsule production and modulate expression of surface structures. Most importantly, mutants expressing single, defined surface polysaccharides are defective for intestinal colonization compared with bacteria expressing a complete polysaccharide repertoire. Restoring the expression of multiple capsular polysaccharides rescues the inability of mutants to compete for commensalism. These findings suggest a model whereby display of multiple capsular polysaccharides provides essential functions for bacterial colonization during host–symbiont mutualism