Inmigrantes españoles en la Provincia del Paraguay. 1776-1811

El presente trabajo se refiere a las características de los inmigrantes españoles en la Provincia del Paraguay, entre 1776 y 1811. La motivación para ahondar en el tema ha sido el deseo de constatar el rol protagónico a nivel político y socioeconómico que los mismos tuvieron en la sociedad de la época, puesto de relieve en los libros de historia tradicionales. Las fuentes a las cuales recurrimos han sido testamentos de los inmigrantes, hallados en el Archivo Nacional de Asunción (A.N.A), ya que estos poseen datos tales como lugar de procedencia de los testamentarios, oficios, monto parcial o total de bienes, entre otros interesantes datos

Salinity and SO4 and Br enrichment of seawater and frost flowers near Barrow, Alaska

Frost flowers have been proposed to be the major source of sea-salt aerosol to the atmosphere during polar winter and a source of reactive bromine during polar springtime. However little is known about their bulk chemical composition or microstructure, two important factors that may affect their ability to produce aerosols and provide chemically reactive surfaces for exchange with the atmosphere. Therefore, we chemically analyzed 28 samples of frost flowers and parts of frost flowers collected from sea ice off of northern Alaska. Our results support the proposed mechanism for frost flower growth that suggests water vapor deposition forms an ice skeleton that wicks brine present on newly grown sea ice. We measured a high variability in sulfate enrichment factors (with respect to chloride) in frost flowers and seawater from the vicinity of freezing sea ice. The variability in sulfate indicates that mirabilite precipitation (Na2SO4 x 10 H2O) occurs during frost flower growth. Brine wicked up by frost flowers is typically sulfate depleted, in agreement with the theory that frost flowers are related to sulfate-depleted aerosol observed in Antarctica. The bromide enrichment factors we measured in frost flowers are within error of seawater composition, constraining the direct reactive losses of bromide from frost flowers. We combined the chemical composition measurements with temperature observations to create a conceptual model of possible scenarios for frost flower microstructure development.