Horizontal profiles of longwave and shortwave radiation components over sea ice near Barrow, Alaska during the 2011 melt

An integrated instrument package for measuring and understanding the surface radiation budget of sea ice is presented, along with results from its first deployment. The setup simultaneously measures broadband fluxes of upwelling and downwelling terrestrial and solar radiation (four components separately), spectral fluxes of incident and reflected solar radiation, and supporting data such as air temperature and humidity, surface temperature, and location (GPS), in addition to photographing the sky and observed surface during each measurement. The instruments are mounted on a small sled, allowing measurements of the radiation budget to be made at many locations in the study area to see the effect of small-scale surface processes on the large-scale radiation budget. Such observations have many applications, from calibration and validation of remote sensing products to improving our understanding of surface processes that affect atmosphere-snow-ice interactions and drive feedbacks, ultimately leading to the potential to improve climate modelling of ice-covered regions of the ocean. The photographs, spectral data, and other observations allow for improved analysis of the broadband data. An example of this is shown by using the observations made during a partly cloudy day, which show erratic variations due to passing clouds, and creating a careful estimate of what the radiation budget along the observed line would have been under uniform sky conditions, clear or overcast. Other data from the setup's first deployment, in June 2011 on fast ice near Point Barrow, Alaska, are also shown; these illustrate the rapid changes of the radiation budget during a cold period that led to refreezing and new snow well into the melt season.

Collection of data on soil carbon (particulate and dissolved) in the Jena Experiment (Main Experiment, time series since 2002)

This data set contains three time series of measurements of soil carbon (particular and dissolved) from the main experiment plots of a large grassland biodiversity experiment (the Jena Experiment; see further details below). In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). Plots were maintained by bi-annual weeding and mowing. 1. Particulate soil carbon: Stratified soil sampling was performed every two years since before sowing in April 2002 and was repeated in April 2004, 2006 and 2008 to a depth of 30 cm segmented to a depth resolution of 5 cm giving six depth subsamples per core. Total carbon concentration was analyzed on ball-milled subsamples by an elemental analyzer at 1150°C. Inorganic carbon concentration was measured by elemental analysis at 1150°C after removal of organic carbon for 16 h at 450°C in a muffle furnace. Organic carbon concentration was calculated as the difference between both measurements of total and inorganic carbon. 2. Particulate soil carbon (high intensity sampling): In one block of the Jena Experiment soil samples were taken to a depth of 1 m (segmented to a depth resolution of 5 cm giving 20 depth subsamples per core) with three replicates per block ever 5 years starting before sowing in April 2002. Samples were processed as for the more frequent sampling. 3. Dissolved organic carbon: Suction plates installed on the field site in 10, 20, 30 and 60 cm depth were used to sample soil pore water. Cumulative soil solution was sampled biweekly and analyzed for dissolved organic carbon concentration by a high TOC elemental analyzer. Annual mean values of DOC are provided.

Un copista-autor : Francisco de Paula Castañeda en Doña María Retazos (1821-1823)

En el marco polifónico e intertextual de la construcción enunciativa del periódico Doña María Retazos (1821-1823), Francisco de Paula Castañeda formula una figura de autor que se expone como scriptor de antiguallas, operación devenida, paradójicamente, en la configuración de un autor moderno, es decir, un periodista

Soil carbon in the Jena Experiment (all blocks Main Experiment up to 30cm depth, year 2006)

This data set contains soil carbon measurements (Organic carbon, inorganic carbon, and total carbon; all measured in dried soil samples) from the main experiment plots of a large grassland biodiversity experiment (the Jena Experiment; see further details below). In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). Plots were maintained by bi-annual weeding and mowing. Soil sampling and analysis: Stratified soil sampling was performed in April 2006 to a depth of 30 cm. Three samples per plot were taken using a split tube sampler with an inner diameter of 4.8 cm (Eijkelkamp Agrisearch Equipment, Giesbeek, the Netherlands). Sampling locations were less than 30 cm apart from sampling locations in 2002. Soil samples were segmented into 5 cm depth segments in the field (resulting in six depth layers) and made into composite samples per depth. Subsequently, samples were dried at 40°C. All soil samples were passed through a sieve with a mesh size of 2 mm. Because of much higher proportions of roots in the soil, samples in years after 2002 were further sieved to 1 mm according to common root removal methods. No additional mineral particles were removed by this procedure. Total carbon concentration was analyzed on ball-milled subsamples (time 4 min, frequency 30 s**-1) by an elemental analyzer at 1150°C (Elementaranalysator vario Max CN; Elementar Analysensysteme GmbH, Hanau, Germany). We measured inorganic carbon concentration by elemental analysis at 1150°C after removal of organic carbon for 16 h at 450°C in a muffle furnace. Organic carbon concentration was calculated as the difference between both measurements of total and inorganic carbon.

La vestimenta de los esclavos en el Buenos Aires posrevolucionario : Un análisis a través de los avisos de fugas y extravíos publicados en La Gaceta Mercantil de Buenos Aires (1823-1831)

Un relevamiento cualitativo y cuantitativo de los avisos de fugas y extravíos de esclavos publicados en La Gaceta Mercantil entre 1823 y 1831 nos permitió analizar pormenorizadamente los atuendos que utilizaba dicho grupo social, sus estados, telas y colores, y cuestionar la visión recibida de los contemporáneos sobre un esclavo mal vestido y harapiento. Comprobamos que vestían mayor variedad y cantidad de prendas, lo cual pudo representar, junto con los ornamentos que complementaron sus ajuares y cierto cuidado en la apariencia personal, una forma de reafirmación de la propia individualidad y el intento de preservación de la identidad de grupo

Enfiteutas, propietarios, agregados y ocupantes en el 'nuevo sur': los partidos de Arenales y Ayacucho (1823-1860)

Este artículo se centra en la ocupación y apropiación de tierras en una región del sudeste de la provincia de Buenos Aires, que integraba en las primeras décadas del siglo XIX el llamado "nuevo sur": los partidos de Arenales y Ayacucho, entre 1823 y 1860. Comenzaremos por caracterizar el traspaso de estos territorios a particulares, el impacto de las distintas modalidades de transferencia y la evolución de la estructura de tenencia. Esto nos llevará a interrogarnos por los protagonistas de este proceso: ¿quiénes fueron los beneficiarios de este reparto? ¿cómo llegaron a estas tierras del "nuevo sur"? ¿cómo fue la conformación del grupo de propietarios en esta zona?, ¿permanecieron los mismos apellidos a lo largo del período? Además, ¿existieron, en esta zona como en otras regiones, posibilidades de ocupación sin la tenencia legal? La comparación con otros procesos de ocupación y apropiación de terrenos del estado, especialmente al sur del río Salado, nos posibilitará una visión más completa de este caso, que obviamente está integrado en un proceso más amplio.