A data-driven analysis to question epidemic models for citation cascades on the blogosphere

Citation cascades in blog networks are often considered as traces of information spreading on this social medium. In this work, we question this point of view using both a structural and semantic analysis of five months activity of the most representative blogs of the french-speaking community.Statistical measures reveal that our dataset shares many features with those that can be found in the literature, suggesting the existence of an identical underlying process. However, a closer analysis of the post content indicates that the popular epidemic-like descriptions of cascades are misleading in this context.A basic model, taking only into account the behavior of bloggers and their restricted social network, accounts for several important statistical features of the data.These arguments support the idea that citations primary goal may not be information spreading on the blogosphere.Comment: 18 pages, 9 figures, to be published in ICWSM-13 proceeding

Effects of Slag-Based Fertilizer to Mitigate Salinity Stress on Greenhouse Durum Wheat (Triticum Durum Desf.) Cultivars

For a modern agricultural, the search for sustainable practices to increase productivity is fundamental. Steel slag have been studied for their potential use in agriculture. These substances present a great possibility of agricultural applications since they are rich in nutrients, which enhance plant uptake. In this regard, the effect of steel slag based-fertilizer was investigated in the greenhouse durum wheat cultivation in pots under salt-stress conditions. Two slag doses: 10 g slag/ kg soil (D1) and 20 g slag/ kg soil (D2) were evaluated under no salt-stress (0 mM NaCl) and salt-stress conditions (100 mM NaCl) for salinity stress mitigation. Morpho-physiological and biochemical parameters of wheat were measured and compared to the different treatments. Wheat exposure to salinity decreased its biomass, stomatal conductance, efficiency of photosystem II, protein content and increased total soluble sugars, hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents. Amended plants with 10 g slag/ kg soil (D1), led to a significant improve in biomass with an increase of shoot and root dry weights (133% and 400% respectively), stomatal conductance (22 %), soluble sugars (14 %) and protein content (158%) under salinity conditions as compared to the control treatment 0 g slag/ kg soil (C), indicating a positive influence on durum wheat plants. However, soil enrichment with 20 g slag/ kg soil (D2) decreased plant growth parameters and presented the highest levels of H2O2 and MDA contents compared to the control and treatment D1 after three months of cultivation under salt-stress. This study supports the hypothesis of the application of slag at lower dose improve productivity of durum wheat and mitigate salinity stress

Effects of Slag Applications and Salinity Stress on Greenhouse Durum Wheat (Triticum durum Desf.) Plants

The search for sustainable practices to increase productivity is a fundamental need in current agriculture. Steel slag has been studied for its potential use in agriculture. These substances present a great ability of agricultural applications since they are rich in nutrients. The effect of steel slag-based fertilizer was investigated on greenhouse durum wheat cultivar under salt-stress conditions. Two doses of slag: 10 g slag/ kg soil (D1) and 20 g slag/ kg soil (D2) were evaluated under no salt-stress (0 mM NaCl) and salt-stress conditions (100 mM NaCl) for salinity stress mitigation. Morpho-physiological and biochemical parameters of wheat were measured and compared to the different treatments. Exposure of wheat to salinity decreased its biomass, stomatal conductance, efficiency of photosystem II, and protein content, but it increased total soluble sugars, hydrogen peroxide (H2O2), and malondialdehyde (MDA) contents. Amended plants with 10 g slag/ kg soil (D1) led to a significant improvement in biomass with an increase of shoot and root dry weights (133% and 400% respectively), stomatal conductance (22 %), soluble sugars (14 %), and protein content (158%) under saline conditions compared to the control treatment with 0 g slag/ kg soil (C), thus indicating a positive influence on durum wheat plants. Soil enrichment with 20 g slag/kg soil (D2) decreased plant growth parameters and presented the highest levels of H2O2 and MDA contents compared to the control and treatment (D1) after three months of cultivation under salt stress. This study supports the hypothesis of the application of slag at lower dose, which improves productivity of durum wheat and mitigate salinity stress

Effects of Slag-Based Fertilizer to Mitigate Salinity Stress on Greenhouse Durum Wheat (Triticum Durum Desf.) Cultivars

For a modern agricultural, the search for sustainable practices to increase productivity is fundamental. Steel slag have been studied for their potential use in agriculture. These substances present a great possibility of agricultural applications since they are rich in nutrients, which enhance plant uptake. In this regard, the effect of steel slag based-fertilizer was investigated in the greenhouse durum wheat cultivation in pots under salt-stress conditions. Two slag doses: 10 g slag/ kg soil (D1) and 20 g slag/ kg soil (D2) were evaluated under no salt-stress (0 mM NaCl) and salt-stress conditions (100 mM NaCl) for salinity stress mitigation. Morpho-physiological and biochemical parameters of wheat were measured and compared to the different treatments. Wheat exposure to salinity decreased its biomass, stomatal conductance, efficiency of photosystem II, protein content and increased total soluble sugars, hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents. Amended plants with 10 g slag/ kg soil (D1), led to a significant improve in biomass with an increase of shoot and root dry weights (133% and 400% respectively), stomatal conductance (22 %), soluble sugars (14 %) and protein content (158%) under salinity conditions as compared to the control treatment 0 g slag/ kg soil (C), indicating a positive influence on durum wheat plants. However, soil enrichment with 20 g slag/ kg soil (D2) decreased plant growth parameters and presented the highest levels of H2O2 and MDA contents compared to the control and treatment D1 after three months of cultivation under salt-stress. This study supports the hypothesis of the application of slag at lower dose improve productivity of durum wheat and mitigate salinity stress

Information diffusion and community structure in a blog network

On peut modéliser de nombreux objets issus du monde réel par des graphes. Ces objets sont issus de contextes très différents (ex. réseaux informatiques, sociaux ou biologiques), cependant ils se ressemblent au sens de certaines propriétées statistiques. On les désigne sous le terme général de graphes de terrain (complex networks en anglais) ou grands graphes d'interaction. L'analyse des graphes de terrain est probablement le plus grand champ de recherche du domaine et l'étude des phénomènes de diffusion constitue un des axes importants dans la compréhension de ces objets. Beaucoupde précédentes études ont été menées sur la diffusion avec une approche théorique mais avec l'apparition de données issues du monde réel de plus en plus riches, une approche empirique de l'analyse de ces réseaux est apparue comme une nécessité. La diffusion peut être de différentes natures: diffusion d'information, d'idées ou d'opinion. Cette diffusion est vue dans la plupart des travaux comme le résultat de l'interaction entre les éléments du réseau (i.e. les nœuds du graphe). En complément de cette vision, nous considérons dans cette thèse que la diffusion, en plus de se produire entre les nœuds, est aussi le résultat de l'interaction entre des groupes de nœuds, appelés communautés, qui ont des propriétés en commun. On dit que le réseau possède une structure en communautés. Cette approche ouvre de nouvelles perspectives pour la compréhension et la caractérisation des graphes de terrain. L'objectif de cette thèse est d'étudier les phénomènes de diffusion de manière empirique non seulement à l'échelle des nœud mais à différents niveaux de la structure en communautés. A l'aide d'une approche statistique, nous proposons un ensemble de méthodes et de métriques pour aborder la diffusion sous un nouvel angle et aller plus loin dans la caractérisation de ces phénomènes .Nous nous proposons d'étudier les liens de diffusion au sein d'un réseau de blogs francophones. Nous montrons en premier lieu l'impact des communautés sur la popularité des blogs et distinguons des classes de comportement. Cela nous conduit à investiguer les interactions entre les communautés. Pour ce faire, nous définissons deux mesures: la distance communautaire et l'Homophilie. En dernier lieu, nous étudions la diffusion de proche on proche dans le graphe, caractérisée par des cascades de diffusion. Nous montrons que notre approche permet de détecter et d'interpréter les différents comportements de diffusion et de faire le lien entre les propriétés topologiques, temporelles et communautaires.PARIS-BIUSJ-Mathématiques rech (751052111) / SudocSudocFranceF

Some Insight on Dynamics of Posts and Citations in Different Blog Communities

International audienceThis paper explores new approaches and methods to characterize post and citation dynamics in different blog communities. In particular, evolution of post popularity over time is studied, as well as information spreading cascades. This methodology goes beyond traditional approaches by defining classes of dynamic behaviors based on topological features of the post network, and by investigating the impact of topical communities on post popularity dynamics and on information spreading cascades. This methodology has been applied to a corpus of active French blogs monitored during 4 months

Citations among blogs in a hierarchy of communities: method and case study

International audienceIn this paper we propose a generic methodology to study the correlation between nodes interactions in complex networks and their organization into groups called communities. We illustrate it on citations in a blog network. We first define a homophily probability evaluating the tendency of blogs to cite blogs from the same community. We then introduce the notion of community distance to capture whether a blog cites (or is cited by) blogs distant or not from its community. We analyze the distribution of distances corresponding to each citation link, and use it to build maps of relevant communities which help interpreting blogs interactions.This community-oriented approach allows us to study citation links at various abstraction levels, and conversely, to characterize communities with regard to their citation behaviour

Role of the Website Structure in the Diversity of Browsing Behaviors

International audienceThe quantitative measurement of the diversity of information consumption has emerged as a prominent tool in the examination of relevant phenomena such as filter bubbles. This paper proposes an analysis of the diversity of the navigation of users inside a website through the analysis of server log files. The methodology, guided and illustrated by a case study, but easily applicable to other cases, establishes relations between types of users' behavior, site structure, and diversity of web browsing. Using the navigation paths of sessions reconstructed from the log file, the proposed methodology offers three main insights: 1) it reveals diversification patterns associated with the page network structure, 2) it relates human browsing characteristics (such as multi-tabbing or click frequency) with the degree of diversity, and 3) it helps identifying diversification patterns specific to subsets of users. These results are in turn useful in the analysis of recommender systems and in the design of websites when there are diversity-related goals or constrains