Furnaces, minerals and slags: an approximation to extractive metallurgy in the puna of jujuy during pre-hispanic and colonial times

Se presentan los resultados de los análisis arqueométricos realizados sobre escorias recuperadas en seis sitios arqueológicos de la Puna de Jujuy (Argentina), uno probablemente de época prehispánica tardía y los otros cinco de época colonial. Las escorias se observaron y analizaron con técnicas de microscopía óptica, electrónica y de microanálisis químico. Estos resultados, en conjunto con la información contextual y el estudio de las evidencias de hornos conservados en los sitios, apuntaron a conocer la naturaleza de la carga mineral y las condiciones de los procesos metalúrgicos llevados a cabo en cada uno de los sitios. En líneas generales, los resultados obtenidos permiten plantear que en todos los casos se desarrolló la metalurgia extractiva de sulfuros de plomo con contenidos de plata (galena argentífera), con el objetivo de obtener este último metal. Es interesante señalar que hasta el momento no se han identificado diferencias destacadas entre los desechos de fundición producidos por el beneficio en hornos de reverbero y otro tipo de hornos, ni entre la producción colonial y la probablemente prehispánica.We present the results of archaeo-metric analyses conducted on slags recovered in six archaeological sites in the Puna of Jujuy (Argentina). One of them was probably in use during pre-Hispanic times and the other five in colonial times. The slag pieces were observed and analysed using optical and electronic microscopy, and chemical microanalysis techniques. These results, together with contextual information and the study of the evidence of furnaces preserved in the sites, aimed at ascertaining the nature of the mineral ore and conditions of metallurgical processes carried out in each site. Overall, the results allow us to state that in all cases extractive metallurgy of lead sulfide with content of silver (argentiferous galena) was carried out in order to obtain the latter. Interestingly, marked differences between casting waste produced by the benefit in reverberatory furnaces and other furnaces, or between colonial and probably Hispanic production, have not been identified.Fil: Becerra, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Estudios Sociales. Universidad Nacional de Tucuman. Instituto Superior de Estudios Sociales; ArgentinaFil: Nieva, Nicolás. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; ArgentinaFil: Angiorama, Carlos Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Instituto Superior de Estudios Sociales. Universidad Nacional de Tucuman. Instituto Superior de Estudios Sociales; Argentin

EFFECTS OF GLYPHOSATE ON GERMINATION AND PHOTOSYNTHESIS IN Prosopis alba G.: A BIOCHEMICAL APPROACH

In recent decades, the phytogeographic region of the Western Chaco has been subjected to heavy deforestation. The native forest was gradually replaced by agricultural crops using high doses of herbicides. Glyphosate is the most widely used herbicide, and its impact on the surrounding native flora is unknown. The aim of this work was to determine the effect of glyphosate on the germination of Prosopis alba seeds and the photosynthesis of seedlings.  Seeds were placed between paper towels, moistened with solutions of 0, 10, 20, 20, 30 and 40 mg a.i. glyphosate l-1, in a growth chamber at 25 oC and a 12 h photoperiod. The percentage of germinated seeds and the mean germination time were calculated. The respiratory rate was measured in these seeds, and the activity of complexes I and III of the respiratory chain was quantified. The shikimate concentration and antioxidant response of the seeds were also quantified. Chlorophyll a fluorescence emission variables were measured in the cotyledons. It was concluded that glyphosate inhibits germination in P. alba seeds and decreases the speed of the process.  This effect can partly be explained by inhibition of respiration, mainly at the level of complex III of the mitochondrial electron transport chain. It is also due to oxidative stress produced by the herbicide, since the antioxidant response of the seeds fails to compensate for the high production of reactive oxygen species. Glyphosate inhibits the photochemical stage of photosynthesis on P. alba cotyledons

Wetland Loss by Erosion in Odiel Marshes (SW Spain)

Wetland loss in many estuaries around the world, has been attributed mainly to undermining and collapse of channel banks. This study aims to quantify bank erosion and vertical erosion/accretion rates on intertidal sediments in the Odiel tidal marshes (SW Spain). Bi-monthly erosion/accretion measurements were taken on eight channels over a four year period, using markers (iron stakes) located on intertidal areas and on eroding banks. The intensity of erosion divides the Odiel marshes into two zones. The northern zone has low erosion rates (horizontal erosion c. -20 cm year-1 and vertical erosion / accretion between 0 and -1 cm year-1), and coincides with low levels of human activities. The southern zone has higher erosion rates (horizontal erosion c. -25 cm year-1 and vertical erosion / accretion between 0 and -5 cm year-1) and exhibits higher levels of anthropogenic pressure. The highest horizontal and vertical erosion rates (c. -80 cm year-1) were recorded on navigation channels. Horizontal and vertical erosion showed a positive linear relationship (r2 = 0.66; P< 0.01), indicating that sediments mobilized by bank erosion are not deposited on adjacent intertidal areas. Erosion led to mature marsh habitat loss of c. 17000 m2 year-1 and a sediment mobilization of c. 16500 m3 year-1

Franz-Keldysh effect in epitaxial ZnO thin films

Photoconductance spectroscopy has been studied in epitaxial ZnO thin films with different thicknesses that range between 136 and 21 nm. We report a systematic decrease in photoconductivity and a red shift in band edge photoconductance spectra when the thickness is reduced. For thinner films, it is found that the effective energy gap value diminishes. By time dependent photoconductivity measurements, we found an enhanced contribution of the slow relaxation times for thicker films. These effects are interpreted in terms of a band-bending contribution where the Franz-Keldysh effect and the polarization of ZnO play a major role in thinner films.Fil: Bridoux, German. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Villafuerte, Manuel Jose. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Ferreyra, Jorge Mario. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Guimpel, Julio Juan. Comisión Nacional de Energía Atómica; Argentina. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nieva, Gladys Leonor. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Figueroa, Carlos Alejandro. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Straube, Benjamin. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; ArgentinaFil: Pérez, Silvia Inés. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Sólido; Argentina. Universidad Nacional de Tucumán. Instituto de Física del Noroeste Argentino. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Instituto de Física del Noroeste Argentino; Argentin

Spatial predictions of human and natural-caused wildfire likelihood across Montana (USA)

Spatial wildfire ignition predictions are needed to ensure efficient and effective wildfire response, and robust methods for modeling new wildfire occurrences are ever-emerging. Here, ignition locations of natural and human-caused wildfires across the state of Montana (USA) from 1992 to 2017 were intersected with static, 30 m resolution spatial data that captured topography, fuel availability, and human transport infrastructure. Once combined, the data were used to train several simple and multiple logistic generalized linear models (GLMs) and generalized additive models (GAMs) to predict the spatial likelihood of natural and human-caused ignitions. Increasingly more complex models that included spatial smoothing terms were better at distinguishing locations with and without natural and human-caused ignitions, achieving area under the receiver operating characteristic curves (AUCs) of 0.84 and 0.89, respectively. Whilst both ignition types were more likely to occur at intermediate fuel loads, as characterized by the local maximum Normalized Difference Vegetation Index (NDVI), naturally-ignited wildfires were more locally influenced by slope, while human-caused wildfires were more locally influenced by distance to roads. Static maps of ignition likelihood were verified by demonstrating that mean annual ignition densities (# yr−1 km−1) were higher within areas of higher predicted probabilities. Although the spatial models developed herein only address the static component of wildfire hazard, they provide a foundation upon which dynamic data can be superimposed to forecast and map wildfire ignition probabilities statewide on a timely basis.This research funded in part by Project FIREPATHS (PID2020-116556RA-I00), Spanish Ministry of Science and Innovation

Saurofagia y canibalismo en dos especies de lagartos del centro-oeste de Argentina

El canibalismo y la saurofagia han sido registrados en numerosas especies de anfibios y reptiles. En la mayoría de los casos esta estrategia predatoria aparece como oportunista y como resultado de un comportamiento predatorio normal. Por otra parte, ambas conductas alimentarias han sido reportadas en lagartos como consecuencia de descubrimientos fortuitos o bien a partir de estudios de ecología del comportamiento. Además es sabido que algunos casos de canibalismo en reptiles pueden ser inducidos por condiciones de cautiverio, lo que no indica que este comportamiento no ocurra naturalmente. El objetivo de este trabajo es aportar nuevos casos a los estudios que se realizan en este sentido, reportando el hallazgo accidental de canibalismo en Cnemidophorus longicauda y saurofagia en Homonota underwoodi ambas especies sintópicas del Monte de San Juan.Asociación Herpetológica Argentina (AHA

Nuevo registro y confirmación de Leiosaurus paronae (Peracca, 1897) (Squamata: Leiosauridae) en la provincia de San Juan, Argentina

We report the first record of Leiosaurus paronae in the department Valle Fértil, San Juan province, Argentina. In December 2015 and January 2016 they were collected and identified two individuals, an adult female (SVL 79 mm) and a juvenile (SVL 44 mm). They were then deposited in the herpetological collection of the Universidad Nacional de San Juan. With this new record, we confirm the presence of Leiosaurus paronae for the province of San Juan.Fil: Gómez Alés, Carlos Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; ArgentinaFil: Castro, Susana Alejandra. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Nieva Cocilio, Rodrigo Alfredo. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Galdeano Ruiz, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; ArgentinaFil: Blanco, Graciela Mirta. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Acosta, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Biología; Argentin

Nuevo registro y confirmación de <i>Leiosaurus paronae</i> (Peracca, 1897) (Squamata: Leiosauridae) en la provincia de San Juan, Argentina

We report the first record of Leiosaurus paronae in the department Valle Fértil, San Juan province, Argentina. In December 2015 and January 2016 were collected and identified two individuals, an adult female (SVL 79 mm) and a juvenile (SVL 44 mm). The specimens were then deposited in the herpetological collection of the Universidad Nacional de San Juan. With this new record, we confirm the presence of Leiosaurus paronae for the province of San Juan.Asociación Herpetológica Argentina (AHA