Where are my followers? Understanding the Locality Effect in Twitter

Twitter is one of the most used applications in the current Internet with more than 200M accounts created so far. As other large-scale systems Twitter can obtain enefit by exploiting the Locality effect existing among its users. In this paper we perform the first comprehensive study of the Locality effect of Twitter. For this purpose we have collected the geographical location of around 1M Twitter users and 16M of their followers. Our results demonstrate that language and cultural characteristics determine the level of Locality expected for different countries. Those countries with a different language than English such as Brazil typically show a high intra-country Locality whereas those others where English is official or co-official language suffer from an external Locality effect. This is, their users have a larger number of followers in US than within their same country. This is produced by two reasons: first, US is the dominant country in Twitter counting with around half of the users, and second, these countries share a common language and cultural characteristics with US

Is Content Publishing in BitTorrent Altruistic or Profit-Driven

BitTorrent is the most popular P2P content delivery application where individual users share various type of content with tens of thousands of other users. The growing popularity of BitTorrent is primarily due to the availability of valuable content without any cost for the consumers. However, apart from required resources, publishing (sharing) valuable (and often copyrighted) content has serious legal implications for user who publish the material (or publishers). This raises a question that whether (at least major) content publishers behave in an altruistic fashion or have other incentives such as financial. In this study, we identify the content publishers of more than 55k torrents in 2 major BitTorrent portals and examine their behavior. We demonstrate that a small fraction of publishers are responsible for 66% of published content and 75% of the downloads. Our investigations reveal that these major publishers respond to two different profiles. On one hand, antipiracy agencies and malicious publishers publish a large amount of fake files to protect copyrighted content and spread malware respectively. On the other hand, content publishing in BitTorrent is largely driven by companies with financial incentive. Therefore, if these companies lose their interest or are unable to publish content, BitTorrent traffic/portals may disappear or at least their associated traffic will significantly reduce

Analyzing gender inequality through large-scale Facebook advertising data

Online social media are information resources that can have a transformative power in society. While the Web was envisioned as an equalizing force that allows everyone to access information, the digital divide prevents large amounts of people from being present online. Online social media in particular are prone to gender inequality, an important issue given the link between social media use and employment. Understanding gender inequality in social media is a challenging task due to the necessity of data sources that can provide large-scale measurements across multiple countries. Here we show how the Facebook Gender Divide (FGD), a metric based on aggregated statistics of more than 1.4 Billion users in 217 countries, explains various aspects of worldwide gender inequality. Our analysis shows that the FGD encodes gender equality indices in education, health, and economic opportunity. We find gender differences in network externalities that suggest that using social media has an added value for women. Furthermore, we find that low values of the FGD are associated with increases in economic gender equality. Our results suggest that online social networks, while suffering evident gender imbalance, may lower the barriers that women have to access informational resources and help to narrow the economic gender gap

Dispersion properties of plasmonic sub-wavelength elliptical wires wrapped with graphene

One fundamental motivation to know the dispersive or frequency dependent characteristics of localized surface plasmons (LSPs) supported by elliptical shaped particles wrapped with a graphene sheet, as well as their scattering characteristics when these elliptical LSPs are excited, is related to the design of plasmonic structures capable of manipulating light at sub-wavelength scale. The anisotropy imposed by ellipse eccentricity can be used as a geometrical tool for controlling plasmonic resonances. Unlike the metallic case, where multipolar eigenmodes are independent of each other, we find that the induced current on a graphene boundary couples multipolar eigenmodes with the same parity. In the long wavelength limit, a recursive relation equation for LSPs in terms of the ellipse eccentricity parameter is derived, and explicit solutions at lowest order are presented. In this approximation, we obtain analytical expressions for both the anisotropic polarizability tensor elements and the scattered power when LSPs are excited by plane wave incidence.Fil: Cuevas, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires; Argentina. Universidad Austral. Facultad de Ingeniería; ArgentinaFil: Depine, Ricardo Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentin

Politics in the Facebook era : evidence from the 2016 US presidential elections

Social media enable politicians to personalize their campaigns and target voters who may be decisive for the outcome of elections. We assess the effects of such political "micro-targeting" by exploiting variation in daily advertising prices on Facebook, collected during the course of the 2016 U.S. presidential campaign. We analyze the variation of prices across political ideologies and propose a measure for the intensity of online political campaigns. Combining this measure with information from the ANES electoral survey, we address two fundamental questions: (i) To what extent did political campaigns use social media to micro-target voters? (ii) How large was the effect, if any, on voters who were heavily exposed to campaigning on social media? We find that online political campaigns targeted on users' gender, geographic location, and political ideology had a signicant eect in persuading undecided voters to support Mr Trump, and in persuading Republican supporters to turn out on polling day. Moreover the effect of micro-targeting on Facebook was strongest among users without university or college-level education