Mapping urban socioeconomic inequalities in developing countries through Facebook advertising data

Ending poverty in all its forms everywhere is the number one Sustainable Development Goal of the UN 2030 Agenda. To monitor the progress toward such an ambitious target, reliable, up-to-date and fine-grained measurements of socioeconomic indicators are necessary. When it comes to socioeconomic development, novel digital traces can provide a complementary data source to overcome the limits of traditional data collection methods, which are often not regularly updated and lack adequate spatial resolution. In this study, we collect publicly available and anonymous advertising audience estimates from Facebook to predict socioeconomic conditions of urban residents, at a fine spatial granularity, in four large urban areas: Atlanta (USA), Bogotá (Colombia), Santiago (Chile), and Casablanca (Morocco). We find that behavioral attributes inferred from the Facebook marketing platform can accurately map the socioeconomic status of residential areas within cities, and that predictive performance is comparable in both high and low-resource settings. Our work provides additional evidence of the value of social advertising media data to measure human development and it also shows the limitations in generalizing the use of these data to make predictions across countries

UHE and EHE neutrino induced taus inside the Earth

Tau neutrinos interacting inside the Earth produce $\tau$ leptons which thereafter can decay inside the atmosphere. The propagation of extremely energetic \nut's and $\tau$'s through the Earth is studied by means of a detailed Monte Carlo simulation, taking into account all major mechanisms of \nut interactions and $\tau$ energy loss as well as decay modes. The rates of $\tau$'s emerging from the Earth are determined as a function of $\tau$'s energy for several cosmic neutrino models.Comment: 21 pages, accepted for publication in Astroparticle Physic

Widely transparent electrodes based on ultrathin metals

Transparent electrodes made of single-component ultrathin ͑Ͻ10 nm͒ metal films (UTMFs) are obtained by sputtering deposition. We show that the optical transparency of the deposited films (chromium and nickel) is comparable to that of indium tin oxide (ITO) in the visible and near-infrared range ͑0.4-2.5 m͒, while it can be significantly higher in the ultraviolet ͑175-400 nm͒ and mid-infrared ͑2.5-25 m͒ regions. Despite their very small thickness, the deposited UTMFs are also uniform and continuous over the 10 cm substrate, as it is confirmed by the measured low electrical resistivity. The excellent optical and electrical properties, stability, compatibility with active materials, process simplicity, and potential low cost make UTMFs high-quality transparent electrodes for the optoelectronics industry, seriously competing with widely used transparent conductive oxides, such as ITO. In this Letter we show that Cr and Ni films deposited by single-step sputtering can be effective transparent electrodes over the entire wavelength range from the UV ͑175 nm͒ to the mid-IR ͑25 m͒. In fact, a detailed comparison with ITO indicates a similar performance in the VIS range, while significant improvement is found in the UV and IR regions. With the invention of ultrahigh vacuum technologies, it is now possible to deposit thin films with relatively lower impurities and contaminants, which would be the main causes of discontinuities and defects in ultrathin films. Polycrystalline Cr and Ni films of thicknesses of 2, 3.5, 5, and 10 nm were deposited by DC sputtering (Kenosistec Dual Chamber), at room temperature in a pure argon atmosphere of 8 mTorr with power levels of 200 W. It is already intuitive that the surface roughness of the substrate has to be smaller than the thickness of the metal film to be deposited if the latter is to be continuous. The UTMFs were grown on optically polished UV grade silica and silicon substrates of typical rms roughness levels below 1 nm being, respectively, used for UV-VIS and IR measurements. The thicknesses of the films were inferred from the deposition rates. Two different ITO films were also grown on UV grade silica and silicon substrates by e-beam evapo

Porcine Cornea Storage Ex Vivo Model as an Alternative to Human Donor Tissues for Investigations of Endothelial Layer Preservation

Purpose: Due to the growing shortage of human corneas for research, we developed a porcine cornea storage model with qualitative features comparable to human tissues. Methods: We established a decontamination procedure for porcine eye bulbs to ensure corneal storage at 31°C to 35°C for up to 28 days without contamination. We compared human and porcine corneas under hypothermic (2-8°C) or culture (31-35°C) conditions for central corneal thickness (CCT), corneal transparency, endothelial morphology, endothelial cell density (ECD), and a novel method to quantify whole endothelial mortality. We also examined portions of lamellar tissues consisting of Descemet's membrane and endothelial cells under the microscope after Alizarin red staining. Results: Our decontamination procedure reduced corneal contamination from 94% (control corneas without decontamination) to 18% after 28 days of storage at 31°C to 35°C. ECD, CCT, transparency, and morphology were significantly higher in porcine corneas than in human corneas at day 0. Nevertheless, the qualitative parameters of porcine and human corneas showed comparable trends under both investigated storage conditions for up to 14 days. Conclusions: The presented corneal storage model provides a reliable alternative to human tissues for preliminary corneal investigations. Translational Relevance: The porcine cornea storage model can be used to investigate the efficacy and safety of new media, substances, or storage conditions. Furthermore, the method developed to assess the percentage of endothelial mortality is tissue conservative and can be used in eye banks to monitor endothelial mortality during storage of tissues intended for transplantation