Anisotropic AGN Outflows and Enrichment of the Intergalactic Medium

We investigate the cosmological-scale influence of outflows driven by AGNs on metal enrichment of the intergalactic medium. AGNs are located in dense cosmological structures which tend to be anisotropic. We designed a semi-analytical model for anisotropic AGN outflows which expand away along the direction of least resistance. This model was implemented into a cosmological numerical simulation algorithm for simulating the growth of large-scale structure in the universe. Using this modified algorithm, we perform a series of 9 simulations inside cosmological volumes of size $(128 h^{-1}{\rm Mpc})^3$, in a concordance $\Lambda$CDM universe, varying the opening angle of the outflows, the lifetimes of the AGNs, their kinetic fractions, and their level of clustering. For each simulation, we compute the volume fraction of the IGM enriched in metals by the outflows. The resulting enriched volume fractions are relatively small at $z \gtrsim 2.5$, and then grow rapidly afterward up to $z = 0$. We find that AGN outflows enrich from 65% to 100% of the entire universe at the present epoch, for different values of the model parameters. The enriched volume fraction depends weakly on the opening angle of the outflows. However, increasingly anisotropic outflows preferentially enrich underdense regions, a trend found more prominent at higher redshifts and decreasing at lower redshifts. The enriched volume fraction increases with increasing kinetic fraction and decreasing AGN lifetime and level of clustering.Comment: 19 pages, 16 figures, submitted. The version uploaded here does not contain Figs 5, 6 & 7, because of their large sizes. Those can be found along with the full paper at: http://www.astro.phy.ulaval.ca/staff/paramita/AllPages/Talks-Posters/Papers_Thesis/ms_AGNoutflow.pd

Insaka: mobile phone support groups for adolescent pregnant women living with HIV

Background: Mobile phone-based interventions have been demonstrated in different settings to overcome barriers to accessing critical psychosocial support. In this study, we aimed to assess the acceptability and feasibility of a phone-based, peer-to-peer support group intervention for adolescent pregnant women aged 15–24 years living with HIV in Zambia. Methods: Sixty-one consenting participants were recruited from Antenatal Clinics of two large urban communities in Lusaka. They were invited to participate in the mobile phone-based intervention that allowed them to anonymously communicate in a small group led by a facilitator for 4 months. A mixed methods approach was used to assess acceptability and feasibility, including a focus group discussion, pre- and post-intervention interview and analysis of the content of the text message data generated. Results: Participants reported finding the platform “not hard to use” and enjoyed the anonymity of the groups. Seventy-one percent of participants (n = 43) participated in the groups, meaning they sent text messages to their groups. Approximately 12,000 text messages were sent by participants (an average of 169 messages/user and 6 mentors in 6 groups. Topics discussed were related to social support and relationships, stigma, HIV knowledge and medication adherence. Conclusion: The study showed that the intervention was acceptable and feasible, and highlighted the potential of the model for overcoming existing barriers to provision of psychosocial support to this population

Associations of multi-decadal sea-surface temperature variability with US drought

Recent research suggests a link between drought occurrence in the conterminous United States (US) and sea surface temperature (SST) variability in both the tropical Pacific and North Atlantic Oceans on decadal to multidecadal (D2M) time scales. Results show that the Atlantic Multidecadal Oscillation (AMO) is the most consistent indicator of D2M drought variability in the conterminous US during the 20th century, but during the 19th century the tropical Pacific is a more consistent indicator of D2 M drought. The interaction between El Niño-Southern Oscillation (ENSO) and the AMO explain a large part of the D2M drought variability in the conterminous US. More modeling studies are needed to reveal possible mechanisms linking low-frequency ENSO variability and the AMO with drought in the conterminous US.National Oceanographic and Atmospheric Administration//NOAA/Estados UnidosUniversidad de Costa Rica//UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI