3,090 research outputs found

    Link creation and profile alignment in the aNobii social network

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    The present work investigates the structural and dynamical properties of aNobii\footnote{http://www.anobii.com/}, a social bookmarking system designed for readers and book lovers. Users of aNobii provide information about their library, reading interests and geographical location, and they can establish typed social links to other users. Here, we perform an in-depth analysis of the system's social network and its interplay with users' profiles. We describe the relation of geographic and interest-based factors to social linking. Furthermore, we perform a longitudinal analysis to investigate the interplay of profile similarity and link creation in the social network, with a focus on triangle closure. We report a reciprocal causal connection: profile similarity of users drives the subsequent closure in the social network and, reciprocally, closure in the social network induces subsequent profile alignment. Access to the dynamics of the social network also allows us to measure quantitative indicators of preferential linking.Comment: http://www.iisocialcom.org/conference/socialcom2010

    Visual Exploration System for Analyzing Trends in Annual Recruitment Using Time-varying Graphs

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    Annual recruitment data of new graduates are manually analyzed by human resources specialists (HR) in industries, which signifies the need to evaluate the recruitment strategy of HR specialists. Every year, different applicants send in job applications to companies. The relationships between applicants' attributes (e.g., English skill or academic credential) can be used to analyze the changes in recruitment trends across multiple years' data. However, most attributes are unnormalized and thus require thorough preprocessing. Such unnormalized data hinder the effective comparison of the relationship between applicants in the early stage of data analysis. Thus, a visual exploration system is highly needed to gain insight from the overview of the relationship between applicants across multiple years. In this study, we propose the Polarizing Attributes for Network Analysis of Correlation on Entities Association (Panacea) visualization system. The proposed system integrates a time-varying graph model and dynamic graph visualization for heterogeneous tabular data. Using this system, human resource specialists can interactively inspect the relationships between two attributes of prospective employees across multiple years. Further, we demonstrate the usability of Panacea with representative examples for finding hidden trends in real-world datasets and then describe HR specialists' feedback obtained throughout Panacea's development. The proposed Panacea system enables HR specialists to visually explore the annual recruitment of new graduates

    Systematics, Biogeography, and Species Delimitation of the Malagasy Psorospermum (Hypericaceae)

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    Psorospermum belongs to the tribe Vismieae (Hypericaceae). Morphologically, Psorospermum is very similar to Harungana, which also belongs to Vismieae along with another genus, Vismia. Interestingly, Harungana occurs in both Madagascar and mainland Africa, as does Psorospermum; Vismia occurs in both Africa and the New World. However, the phylogeny of the tribe and the relationship between the three genera are uncertain. Using freshly collected specimens from my fieldwork as well as extant herbarium specimens, I aimed first, to generate a phylogeny of Psorospermum; second, to investigate its biogeography; and third, to investigate species boundaries within Malagasy Psorospermum. The results of my molecular phylogenetic work, based on a combined analysis of chloroplast DNA (ndhF; trnL-trnF) and nuclear DNA (ITS), strongly support Harungana and Psorospermum as two genera: Harungana also includes one African species of Vismia, V. rubescens, and Psorospermum includes the other African Vismia and Psorospermum. My results also show that Malagasy Psorospermum are paraphyletic, some African species being nested within the clade of Malagasy Psorospermum suggesting dispersal of the genus westwards back to Africa. I conducted ancestral area reconstruction studies to test this hypothesis. Psorospermum may have reached Madagascar by a single dispersal event from Africa during the Oligocene (ca. 34-22 Ma), followed by diversification on Madagascar after ca. 20-19 Ma. However, two recent dispersal events appear to have occurred out of Madagascar back to Africa in the late Miocene (ca. 5.5 and 5.7 Ma). Malagasy Psorospermum has not had a taxonomic revision in 60 years and the total number of species is uncertain. I undertook a novel approach to investigate the species boundaries in Psorospermum by integrating species hypotheses delimited by both molecular and morphometric analyses. Herbarium specimens of the putative taxa in each well supported clade in the molecular phylogeny of Malagasy Psorospermum were subjected to morphometric analyses using gaussian mixture models. I identified 27 species of Psorospermum of which 11 are new. The results will be used in a taxonomic revision of Malagasy Psorospermum that is in progress

    Data-driven journalism

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    Visual analysis of document triage data

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    As part of the information seeking process, a large amount of effort is invested in order to study and understand how information seekers search through documents such that they can assess their relevance. This search and assessment of document relevance, known as document triage, is an important information seeking process, but is not yet well understood. Human-computer interaction (HCI) and digital library scientists have undertaken a series of user studies involving information seeking, collected a large amount of data describing information seekers' behavior during document search. Next to this, we have witnessed a rapid increase in the number of off-the-shelf visualization tools which can benefit document triage study. Here we set out to utilize existing information visualization techniques and tools in order to gain a better understanding of the large amount of user-study data collected by HCI and digital library researchers. We describe the range of available tools and visualizations we use in order to increase our knowledge of document triage. Treemap, parallel coordinates, stack graph, matrix chart, as well as other visualization methods, prove to be insightful in exploring, analyzing and presenting user behavior during document triage. Our findings and visualizations are evaluated by HCI and digital library researchers studying this proble

    Biological mechanisms of aging predict age-related disease multimorbidities in patients

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    Genetic, environmental and pharmacological interventions into the aging process can confer resistance to a multiple age-related diseases in laboratory animals, including rhesus monkeys. These findings imply that mechanisms of aging might contribute to patterns of multimorbidity in humans, and hence could be targeted to prevent multiple conditions simultaneously. To address this question, we text mined 917,645 literature abstracts followed by manual curation, and found strong, non-random associations between age-related diseases and aging mechanisms, confirmed by gene set enrichment analysis of GWAS data. Integration of these associations with clinical data from 3.01 million patients showed that age-related diseases associated with each of five aging mechanisms were more likely than chance to be present together in patients. Genetic evidence revealed that innate and adaptive immunity, the intrinsic apoptotic signalling pathway and activity of the ERK1/2 pathway played a significant role across multiple aging mechanisms and multiple, diverse age-related diseases. Mechanisms of aging therefore contribute to multiple age-related diseases and to patterns of human age-related multimorbidity, and could potentially be targeted to prevent more than one age-related condition in the same patient

    Biological mechanisms of aging predict age-related disease co-occurrence in patients

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    Genetic, environmental, and pharmacological interventions into the aging process can confer resistance to multiple age-related diseases in laboratory animals, including rhesus monkeys. These findings imply that individual mechanisms of aging might contribute to the co-occurrence of age-related diseases in humans and could be targeted to prevent these conditions simultaneously. To address this question, we text mined 917,645 literature abstracts followed by manual curation and found strong, non-random associations between age-related diseases and aging mechanisms in humans, confirmed by gene set enrichment analysis of GWAS data. Integration of these associations with clinical data from 3.01 million patients showed that age-related diseases associated with each of five aging mechanisms were more likely than chance to be present together in patients. Genetic evidence revealed that innate and adaptive immunity, the intrinsic apoptotic signaling pathway and activity of the ERK1/2 pathway were associated with multiple aging mechanisms and diverse age-related diseases. Mechanisms of aging hence contribute both together and individually to age-related disease co-occurrence in humans and could potentially be targeted accordingly to prevent multimorbidity
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