Dust flux records from the Subarctic North Pacific

We present a new record of eolian dust flux to the western Subarctic North Pacific (SNP) covering the past 27000 years based on a core from the Detroit Seamount. Comparing the SNP dust record to the NGRIP ice core record shows significant differences in the amplitude of dust changes to the two regions during the last deglaciation, while the timing of abrupt changes is synchronous. If dust deposition in the SNP faithfully records its mobilization in East Asian source regions, then the difference in the relative amplitude must reflect climate-related changes in atmospheric dust transport to Greenland. Based on the synchronicity in the timing of dust changes in the SNP and Greenland, we tie abrupt deglacial transitions in the 230Th-normalized 4He flux record to corresponding transitions in the well-dated NGRIP dust flux record to provide a new chronostratigraphic technique for marine sediments from the SNP. Results from this technique are complemented by radiocarbon dating, which allows us to independently constrain radiocarbon paleoreservoir ages. We find paleoreservoir ages of 745 ± 140 yr at 11653 yr BP, 680 ± 228 yr at 14630 yr BP and 790 ± 498 yr at 23290 yr BP. Our reconstructed paleoreservoir ages are consistent with modern surface water reservoir ages in the western SNP. Good temporal synchronicity between eolian dust records from the Subantarctic Atlantic and equatorial Pacific and the ice core record from Antarctica supports the reliability of the proposed dust tuning method to be used more widely in other global ocean regions.

Continuous 25-years aerosol records at coastal Antarctica: Part I. Variability and climate implications of ionic compounds

The aerosol climatology at the coastal Antarctic Neumayer Station (NM) was investigated based on continuous, 25-yr long observations of biogenic sulphur components (methanesulfonate and non-sea salt sulphate), sea salt and nitrate. Although significant long-term trends could only be detected for nitrate (-3.6 ± 2.5% per year between 1983 and 1993 and +4.0 ± 3.2% per year from 1993-2007), non-harmonic periodicities between 2 and 5 yr were typical for all species. Dedicated time series analyses revealed that relations to sea ice extent and various circulation indices are weak at best or not significant. In particular, no consistent link between sea ice extent and sea salt loadings was evident suggesting only a rather local relevance of the NM sea salt record. Nevertheless, a higher Southern Annular Mode index tended to entail a lower biogenic sulphur signal. In examining the spatial uniformity of the NM findings we contrasted them to respective 17 yr records from the coastal Dumont d'Urville Station. We found similar long-term trends for nitrate, indicating an Antarctic-wide but not identifiable atmospheric signal, although any significant impact of solar activity or pollution could be ruled out. No inter-site variability on the multiannual scale was evident for the other ionic compounds.

Política y comunicación : el impacto de la Ley de Servicios de Comunicación Audiovisual en el escenario mediático

El año 2009 significó para Argentina un momento de discusiones que provocaron interpelaciones al sistema democrático. Después 26 años de recuperada la democracia, el Estado modificó la dictatorial legislación que regula los servicios de comunicación audiovisuales. Esto implica una ampliación de la democratización del sistema de medios, tanto en las voces presentes, como en los autorizados para su uso y explotación. Esta nueva legislación permite que más y diversos sujetos puedan hacer uso de su derecho a comunicar y obliga a los oligopolios de la comunicación a ceder parte de sus licencias, de ahí las presiones económicas para frenar la nueva norma.

El impacto de la Ley de Servicios de Comunicación Audiovisual en los diarios mendocinos Los Andes y Uno : un análisis desde la intencionalidad editorial

En base al modelo teórico metodológico de la intencionalidad editorial, que sostiene que el periodismo es objetivo (en tanto remite a fuentes), y parcial (toma de posición), analizamos la cobertura realizada por los diarios Los Andes y UNO sobre la Ley de Servicios de Comunicación Audiovisual. La hipótesis fue que los diarios locales construyeron, a través de piezas periodísticas, un sentido común que respondió a sus intereses corporativos en detrimento del derecho humano a la comunicación. El análisis consistió en un observatorio de medios que combinó metodología cuantitativa y cualitativa, desde el 27 de agosto al 11 de octubre de 2009.