Influence Diffusion in Social Networks under Time Window Constraints

We study a combinatorial model of the spread of influence in networks that generalizes existing schemata recently proposed in the literature. In our model, agents change behaviours/opinions on the basis of information collected from their neighbours in a time interval of bounded size whereas agents are assumed to have unbounded memory in previously studied scenarios. In our mathematical framework, one is given a network G = (V , E), an integer value t(v) for each node v ∈ V , and a time window size λ. The goal is to determine a small set of nodes (target set) that influences the whole graph. The spread of influence proceeds in rounds as follows: initially all nodes in the target set are influenced; subsequently, in each round, any uninfluenced node v becomes influenced if the number of its neighbours that have been influenced in the previous λ rounds is greater than or equal to t(v). We prove that the problem of finding a minimum cardinality target set that influences the whole network G is hard to approximate within a polylogarithmic factor. On the positive side, we design exact polynomial time algorithms for paths, rings, and tree

How to do Qualitative Structural Analysis: The Qualitative Interpretation of Network Maps and Narrative Interviews

Zur Analyse der Einbettung von Akteur/innen in soziale Strukturen werden in der Netzwerkforschung zunehmend offene Forschungszugänge auch in Kombination mit standardisierten methodischen Ansätzen verwendet. Die Entwicklung eines Vorgehens zur qualitativen strukturbezogenen Analyse stellt bislang ein Desiderat dar. Am Beispiel der Analyse einer egozentrierten Netzwerkkarte und eines erzählgenerierenden Interviews entwerfen, explizieren und begründen wir ein methodisches qualitatives Analyseverfahren, das Standards einer strukturalen Analyse – als theoretisch-methodologische Position der sozialen Netzwerkanalyse – Rechnung trägt. Entlang des Beispiels entwerfen wir qualitative Verfahren der Interpretation (Sequenzanalyse, sensibilisierendes Konzept, Memos) für die Auswertung von Netzwerkkarten und des narrativen Materials, für das wir Konzepte der formalen Netzwerkanalyse adaptieren. Unser Vorschlag dieser qualitativen strukturalen Analyse – kurz QSA – stellt damit eine Kombination aus der analytischen Perspektive der strukturalen Analyse mit analytischen Standards der qualitativen Sozialforschung dar.URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs150190Para analizar cómo los actores están involucrados en las estructuras sociales, la investigación de redes está empleando cada vez más métodos cualitativos, a veces en combinación con enfoques estandarizados. Hasta ahora sigue siendo una aspiración desarrollar un método para el análisis estructural cualitativo. Utilizando el ejemplo de análisis de un mapa de red egocéntrico y una entrevista narrativa, conceptualizamos, explicamos y fundamentamos un procedimiento de análisis cualitativo que representa adecuadamente los estándares del análisis estructural en tanto posturas teóricas y metodológicas adoptadas por el análisis de redes sociales. Con base en este ejemplo, diseñamos procedimientos cualitativos (análisis secuencial, conceptos sensibilizadores, memos) para analizar los mapas de red y los datos narrativos. Para ello, adaptamos conceptos del análisis formal de red. Nuestra propuesta para este análisis estructural cualitativo (AEC) es, pues, una combinación de la perspectiva del análisis estructural y de los estándares tomados de la investigación social cualitativa.URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs150190To analyze how actors are embedded in social structures, network research is increasingly using qualitative methods, sometimes in combination with standardized approaches. So far, the development of a method for qualitative structural analysis remains a desideratum. Using the example of the analysis of an ego-centric network map and a narrative interview, we conceptualize, explicate and substantiate a qualitative analysis procedure which does justice to the standards of structural analysis as theoretical and methodological stances taken by social network analysis. Based on this example, we design qualitative procedures (sequential analysis, sensitizing concepts, memos) to analyze network maps and narrative data. To do so, we adapt concepts from formal network analysis. Our proposal for this qualitative structural analysis (QSA) is thus a combination of the analytical perspective of structural analysis and analytical standards taken from qualitative social research.URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs15019

Percepções dos cientistas brasileiros sobre a cobertura de ciência pela mídia e sua relação com os jornalistas: Um estudo qualitativo

O presente estudo traz as percepções de cientistas brasileiros sobre a cobertura de temas da ciência pela mídia e da relação que eles têm com jornalistas. De caráter qualitativo, insere-se em um estudo nacional, no qual foi realizada uma enquete. A partir da enquete, identificamos alguns aspectos que foram aprofundados por meio de entrevistas semiestruturadas, realizadas com 20 cientistas de diferentes áreas de pesquisa e regiões do Brasil. A maioria dos participantes tem uma relação positiva com os jornalistas, mas preferem que as entrevistas se limitem aos temas de sua especialidade, por não se sentirem à vontade de falar sobre assuntos mais amplos do país, como política e economia. Os cientistas entrevistados destacam a necessidade de usar a ética para falar sobre divergências entre pesquisadores e para comentar resultados de estudos realizados por seus pares. Além disso, evitam falar sobre pesquisas ainda não publicadas em periódicos científicos, seja porque essas não passaram pela revisão por pares, seja para preservar a propriedade intelectual de seus resultados. Os entrevistados sentem-se à vontade em falar com a mídia sem pedir autorização a superiores ou a assessores de imprensa, mas preferem não entrar em contato eles mesmos com jornalistas, quando desejam divulgar resultados de seus estudos

Bewegungsförderung in Deutschland: Akteure, Strukturen und Netzwerkentwicklung

Bewegung unterstützt in vielfältiger Weise die Gesundheit von Menschen jeden Lebensalters. Dennoch ist die Prävalenz körperlicher Inaktivität in Deutschland hoch und die meisten Menschen erreichen den von der Weltgesundheitsorganisation empfohlenen Bewegungsumfang nicht. Um gezielte Maßnahmen zur Bewegungsförderung zu unterstützen, ist die Kenntnis der relevanten Akteure, Berufsgruppen und Multiplikatoren sowie deren struktureller Zusammenhang notwendig. Im Rahmen einer explorativen Untersuchung wurden 2 Ziele verfolgt: (1) die Identifikation relevanter Akteure, Berufsgruppen und Multiplikatoren der Bewegungsförderung in Deutschland und (2) die Analyse der strukturellen Vernetzung dieser Akteure sowie die Formulierung von Empfehlungen zur nachhaltigen Entwicklung eines nationalen Netzwerks der Bewegungsförderung. Hierzu wurden qualitative Experteninterviews, eine anschließende Netzwerkvisualisierung und eine Analyse zur Netzwerkentwicklung durchgeführt. Es zeigte sich, dass das Feld der Akteure im Bereich der Bewegungsförderung ausgesprochen heterogen und umfangreich hinsichtlich verschiedener Akteursformen, Gesellschaftsbereiche und Bezugsräume ist. Insgesamt konnten 128 Akteure identifiziert werden. Davon werden 22 Akteure in Schlüsselpositionen gesehen. Bei den Multiplikatoren wurden 19 aktuelle und 17 weitere potenzielle identifiziert. Die strukturelle Vernetzung der Akteure ist nur schwach ausgeprägt. Für eine zukünftige Netzwerkentwicklung konnten verschiedene Voraussetzungen, Vorteile und Barrieren herausgearbeitet werden. Daran anschließend werden Empfehlungen formuliert, welche zur Bildung und effektiven Steuerung eines nationalen Netzwerks der Bewegungsförderung beitragen. Die Studie ermöglicht eine erste differenzierte Betrachtung der Akteursstrukturen der Bewegungsförderung in Deutschland

Dyadic Coping of Kidney Transplant Recipients and Their Partners: Sex and Role Differences

Background: Coping with stressful health issues – e.g., organ transplantation – can affect interpersonal relationships.Objective: The study examines individual and dyadic coping (DC) in kidney transplant recipients and their partners under consideration of sex and role differences. The Dyadic Coping Inventory allows analyzing partners’ perception of their own DC and also of their partner’s behavior and investigating different perspectives with three discrepancy indexes (similarity, perceived similarity, congruence).Methods: Fifty-six kidney transplant recipients and their partners completed self-report questionnaires (N = 112) on DC, depression, anxiety, and relationship satisfaction. The average age of the patients was 58.1 years and of the partners 57.2 years; 64.3% of the patients were male; time since transplantation was on average 9.7 years.Results: (1) Individual and dyadic functioning: In couples with male patients female caregivers showed higher own supportive DC than the males. In couples with female patients, women reported higher own stress communication, supportive DC, total positive DC and total DC as well as depression compared to men. (2) Regarding the discrepancy indexes, in couples with male patients lower levels of similarity in DC reactions of the couple was associated with higher depression of the males as well as higher anxiety of the females. Moreover, lower comparability of the own DC with partner-perception was correlated with higher depression in males. In couples with female patients, higher comparability was associated with higher DC. Higher DC of the males was associated with lower own anxiety and better similarity in DC reactions. Lower levels of similarity of the male spouse showed correlations with higher depression and anxiety of the females. (3) Sex and role differences occurred. No significant differences between male patients and male partners occurred whereas female patients showed higher own stress communication, supportive DC, common DC, total positive DC, total DC and relationship satisfaction compared to female caregivers (role differences). The same differences were found comparing female with male patients. No differences occurred between male and female caregivers (sex differences). (4) Regarding male’s relationship quality, male’s DC total score and similarity index seem to be important predictors in couples with male patients.Discussion: The results demonstrate the relevance of DC in couples with kidney transplantation and show differences between males and females as well as between patients and partners

Wild dogs at stake: deforestation threatens the only Amazon endemic canid, the short-eared dog (Atelocynus microtis)

The persistent high deforestation rate and fragmentation of the Amazon forests are the main threats to their biodiversity. To anticipate and mitigate these threats, it is important to understand and predict how species respond to the rapidly changing landscape. The short-eared dog Atelocynus microtis is the only Amazon-endemic canid and one of the most understudied wild dogs worldwide. We investigated short-eared dog habitat associations on two spatial scales. First, we used the largest record database ever compiled for short-eared dogs in combination with species distribution models to map species habitat suitability, estimate its distribution range and predict shifts in species distribution in response to predicted deforestation across the entire Amazon (regional scale). Second, we used systematic camera trap surveys and occupancy models to investigate how forest cover and forest fragmentation affect the space use of this species in the Southern Brazilian Amazon (local scale). Species distribution models suggested that the short-eared dog potentially occurs over an extensive and continuous area, through most of the Amazon region south of the Amazon River. However, approximately 30% of the short-eared dog's current distribution is expected to be lost or suffer sharp declines in habitat suitability by 2027 (within three generations) due to forest loss. This proportion might reach 40% of the species distribution in unprotected areas and exceed 60% in some interfluves (i.e. portions of land separated by large rivers) of the Amazon basin. Our local-scale analysis indicated that the presence of forest positively affected short-eared dog space use, while the density of forest edges had a negative effect. Beyond shedding light on the ecology of the short-eared dog and refining its distribution range, our results stress that forest loss poses a serious threat to the conservation of the species in a short time frame. Hence, we propose a re-assessment of the short-eared dog's current IUCN Red List status (Near Threatened) based on findings presented here. Our study exemplifies how data can be integrated across sources and modelling procedures to improve our knowledge of relatively understudied species

Chronic Hepatitis B Finite Treatment: similar and different concerns with new drug classes

Chronic hepatitis B, a major cause of liver disease and cancer, affects over 250 million people worldwide. Currently there is no cure, only suppressive therapies. Efforts to develop finite curative HBV therapies are underway, consisting of combinations of multiple novel agents +/- nucleos(t)ide reverse transcriptase inhibitors. The HBV Forum convened a webinar in July 2021, and subsequent working group discussions to address how and when to stop finite therapy for demonstration of sustained off-treatment efficacy and safety responses. Participants included leading experts in academia, clinical practice, pharmaceutical companies, patient representatives and regulatory agencies. This Viewpoint outlines areas of consensus within our multi-stakeholder group for stopping finite therapies in chronic Hepatitis B investigational studies, including trial design, patient selection, outcomes, biomarkers, pre-defined stopping criteria, pre-defined retreatment criteria, duration of investigational therapies, and follow up after stopping therapy. Future research of unmet needs are discussed

A proteomics analysis of 5xFAD mouse brain regions reveals the lysosome-associated protein Arl8b as a candidate biomarker for Alzheimer's disease

BACKGROUND: Alzheimer's disease (AD) is characterized by the intra- and extracellular accumulation of amyloid-β (Aβ) peptides. How Aβ aggregates perturb the proteome in brains of patients and AD transgenic mouse models, remains largely unclear. State-of-the-art mass spectrometry (MS) methods can comprehensively detect proteomic alterations, providing relevant insights unobtainable with transcriptomics investigations. Analyses of the relationship between progressive Aβ aggregation and protein abundance changes in brains of 5xFAD transgenic mice have not been reported previously. METHODS: We quantified progressive Aβ aggregation in hippocampus and cortex of 5xFAD mice and controls with immunohistochemistry and membrane filter assays. Protein changes in different mouse tissues were analyzed by MS-based proteomics using label-free quantification; resulting MS data were processed using an established pipeline. Results were contrasted with existing proteomic data sets from postmortem AD patient brains. Finally, abundance changes in the candidate marker Arl8b were validated in cerebrospinal fluid (CSF) from AD patients and controls using ELISAs. RESULTS: Experiments revealed faster accumulation of Aβ42 peptides in hippocampus than in cortex of 5xFAD mice, with more protein abundance changes in hippocampus, indicating that Aβ42 aggregate deposition is associated with brain region-specific proteome perturbations. Generating time-resolved data sets, we defined Aβ aggregate-correlated and anticorrelated proteome changes, a fraction of which was conserved in postmortem AD patient brain tissue, suggesting that proteome changes in 5xFAD mice mimic disease-relevant changes in human AD. We detected a positive correlation between Aβ42 aggregate deposition in the hippocampus of 5xFAD mice and the abundance of the lysosome-associated small GTPase Arl8b, which accumulated together with axonal lysosomal membranes in close proximity of extracellular Aβ plaques in 5xFAD brains. Abnormal aggregation of Arl8b was observed in human AD brain tissue. Arl8b protein levels were significantly increased in CSF of AD patients. CONCLUSIONS: We report a comprehensive biochemical and proteomic investigation of hippocampal and cortical brain tissue derived from 5xFAD transgenic mice, providing a valuable resource to the neuroscientific community. We identified Arl8b, with significant abundance changes in 5xFAD and AD patient brains. Arl8b might enable the measurement of progressive lysosome accumulation in AD patients and have clinical utility as a candidate biomarker