Universidade Federal de Minas Gerais

About: Universidade Federal de Minas Gerais is a education organization based out in Belo Horizonte, Minas Gerais, Brazil. It is known for research contribution in the topics: Population & Context (language use). The organization has 41631 authors who have published 75688 publications receiving 1249905 citations.

On word-of-mouth based discovery of the web

Abstract: Traditionally, users have discovered information on the Web by browsing or searching. Recently, word-of-mouth has emerged as a popular way of discovering the Web, particularly on social networking sites like Facebook and Twitter. On these sites, users discover Web content by following URLs posted by their friends. Such word-of-mouth based content discovery has become a major driver of traffic to many Web sites today. To better understand this popular phenomenon, in this paper we present a detailed analysis of word-of-mouth exchange of URLs among Twitter users. Among our key findings, we show that Twitter yields propagation trees that are wider than they are deep. Our analysis on the geolocation of users indicates that users who are geographically close together are more likely to share the same URL.

Horizontal equity in health care utilization in Brazil, 1998–2008

Abstract: This study assesses trends in horizontal equity in the utilization of healthcare services from 1998 to 2008--a period of major economic and social change in Brazil. Data are from nationally representative surveys repeated in 1998, 2003, and 2008. We apply established methods for assessing horizontal inequity in healthcare access (the principle that people with the same healthcare needs should have similar access to healthcare services). Horizontal inequity is calculated as the difference between observed healthcare utilization and utilization predicted by healthcare needs. Outcomes examined include the probability of a medical, dental, or hospital visit during the past 12 months; any health service use in the past two weeks; and having a usual source of healthcare. We use monthly family income to measure differences in socioeconomic position. Healthcare needs include age, sex, self-rated health, and chronic conditions. Non-need factors include income, education, geography, health insurance, and Family Health Strategy coverage. The probability of having at least one doctor visit in the past 12 months became substantially more equitable over time, ending with a slightly pro-rich orientation in 2008. Any hospitalization in the past 12 months was found to be pro-poor in all periods but became slightly less so in 2008. Dental visits showed the largest absolute decrease in horizontal inequity, although they were still the most inequitably (pro-rich) distributed outcome in 2008. Service use in the past two weeks showed decreased inequity in 2003 but exhibited no significant change between 2003 and 2008. Having a usual source of care became less pro-rich over time and was nearly income-neutral by 2008. Factors associated with greater inequities include income, having a private health plan, and geographic location. Factors associated with greater equity included health needs, schooling, and enrolment in the Family Health Strategy. Healthcare utilization in Brazil appears to have become increasingly equitable over the past 10 years. Although this does not imply that equity in health outcomes has improved correspondingly, it does suggest that government policies aimed at increasing access, especially to primary care, have helped to make healthcare utilization in Brazil fairer over time.

The Gemini NICI Planet-finding Campaign: Discovery of a Substellar L Dwarf Companion to the Nearby Young M Dwarf CD?35 2722

Abstract: We present the discovery of a wide (67?AU) substellar companion to the nearby (21?pc) young solar-metallicity M1 dwarf CD?35 2722, a member of the 100?Myr AB Doradus association. Two epochs of astrometry from the NICI Planet-Finding Campaign confirm that CD?35 2722?B is physically associated with the primary star. Near-IR spectra indicate a spectral type of L4?1 with a moderately low surface gravity, making it one of the coolest young companions found to date. The absorption lines and near-IR continuum shape of CD?35 2722?B agree especially well the dusty field L4.5 dwarf 2MASS J22244381?0158521, while the near-IR colors and absolute magnitudes match those of the 5?Myr old L4 planetary-mass companion, 1RXS J160929.1?210524 b. Overall, CD?35 2722?B appears to be an intermediate-age benchmark for L dwarfs, with a less peaked H-band continuum than the youngest objects and near-IR absorption lines comparable to field objects. We fit Ames-Dusty model atmospheres to the near-IR spectra and find T eff= 1700-1900?K and log(g)= 4.5 ? 0.5. The spectra also show that the radial velocities of components A and B agree to within ?10?km?s?1, further confirming their physical association. Using the age and bolometric luminosity of CD?35 2722?B, we derive a mass of 31 ? 8 M Jup from the Lyon/Dusty evolutionary models. Altogether, young late-M to mid-L type companions appear to be overluminous for their near-IR spectral type compared with field objects, in contrast to the underluminosity of young late-L and early-T dwarfs.