Detección de señales magnetotelúricas en la banda de 0,1 a 10 Hz

El objetivo fundamental de este trabajo consistió en comprobar la existencia de un nivel mínimo de agitación permanente del campo electromagnético natural, detectable con un instrumental especialmente diseñado, en la banda de 0,1 a 10 Hz y ensayar su utilización en la realización de sondajes magnetotelúricos. Debido a la existencia de un mínimo en el espectro de la agitación natural en los alrededores de 1 Hz, fue necesario desarrollar y optimizar los sensores y amplificadores para los campos eléctrico y magnético, así como recurrir a la utilización de filtros electrónicos para limitar la banda de interés. AL realizarse un sondaje magnetotelúrico (MT) experimental en el sitio de Zárate (Buenos Aires), se comprobó plenamente la hipótesis sobre la existencia de un nivel importante de agitación permanente del campo electromagnético natural. Asimismo, las curvas de resistividad aparente obtenidas son compatibles con los valores esperados a partir de los conocimientos geoestructurales.The fundamental aim of this work was to prove the existence of a minimum level in the permanent activity of the natural electromagnetic field, detectable through a specially designed equipment, in the 0,1 to 10 Hz band. Because of the existence of mininun in the natural activity spectrum near 1 Hz, it was necesary to develop sensors and amplifiers for the telluric and geomagnetic fields, as well as to use electronic filters limiting the extent of detection band. An experimental magnetotelluric sounding at Zárate (Buenos Aires), seems to prove the hypothesis about the existence of an inportant permanent level in the electromagnetic natural activity. Likewise, the apparent resistivity curves obtained ire compatible with the expectable values from the geostructural evidence.Asociación Argentina de Geofísicos y Geodesta

Detección de señales magnetotelúricas en la banda de 0,1 a 10 Hz

El objetivo fundamental de este trabajo consistió en comprobar la existencia de un nivel mínimo de agitación permanente del campo electromagnético natural, detectable con un instrumental especialmente diseñado, en la banda de 0,1 a 10 Hz y ensayar su utilización en la realización de sondajes magnetotelúricos. Debido a la existencia de un mínimo en el espectro de la agitación natural en los alrededores de 1 Hz, fue necesario desarrollar y optimizar los sensores y amplificadores para los campos eléctrico y magnético, así como recurrir a la utilización de filtros electrónicos para limitar la banda de interés. AL realizarse un sondaje magnetotelúrico (MT) experimental en el sitio de Zárate (Buenos Aires), se comprobó plenamente la hipótesis sobre la existencia de un nivel importante de agitación permanente del campo electromagnético natural. Asimismo, las curvas de resistividad aparente obtenidas son compatibles con los valores esperados a partir de los conocimientos geoestructurales.The fundamental aim of this work was to prove the existence of a minimum level in the permanent activity of the natural electromagnetic field, detectable through a specially designed equipment, in the 0,1 to 10 Hz band. Because of the existence of mininun in the natural activity spectrum near 1 Hz, it was necesary to develop sensors and amplifiers for the telluric and geomagnetic fields, as well as to use electronic filters limiting the extent of detection band. An experimental magnetotelluric sounding at Zárate (Buenos Aires), seems to prove the hypothesis about the existence of an inportant permanent level in the electromagnetic natural activity. Likewise, the apparent resistivity curves obtained ire compatible with the expectable values from the geostructural evidence.Asociación Argentina de Geofísicos y Geodesta

Estudios magnetotelúricos en la cuenca del mar de Wedell, cálculo de la matriz de inducción electromagnética terrestre

En este trabajo se revisaron datos magnetotelúricos obtenidos en campañas antárticas, en sitios aledaños a las bases argentinas Marambio y Matienzo, cuya interpretación preliminar ya era conocida. El análisis complementario que aquí se presenta pone énfasis en el cálculo detallado de los elementos del tensor impedancia, la forma de descripción mas general de la inducción en la tierra. Del análisis surgen las siguientes conclusiones: 1) un acuerdo general aceptable con los resultados preliminares, 2) argumentos para considerar válida la hipótesis de una estructura con simetría bidimensional en Marambio, 3) evidencias de una estructura de mayor complejidad en Matienz .In this paper antarctic magnetotelluric data obtained near the argentine bases Marambio and Matienzo were analyzed. Previous preliminary interpretation had been already published. The here presented complementary analysis put emphasis on the calculus of the elements of the impedance tensor, the more general description of the induction in earth phenomena. The conclusions of this analysis are: 1) There is a general agreement with preliminary results, 2) arguments in favour of the two dimensional structure hipothesis are obtained in the Marambio site, 3) there are evidencies of a more complex structure in the Matienzo sounding site.Asociación Argentina de Geofísicos y Geodesta

Estudios magnetotelúricos en la cuenca del mar de Wedell, cálculo de la matriz de inducción electromagnética terrestre

En este trabajo se revisaron datos magnetotelúricos obtenidos en campañas antárticas, en sitios aledaños a las bases argentinas Marambio y Matienzo, cuya interpretación preliminar ya era conocida. El análisis complementario que aquí se presenta pone énfasis en el cálculo detallado de los elementos del tensor impedancia, la forma de descripción mas general de la inducción en la tierra. Del análisis surgen las siguientes conclusiones: 1) un acuerdo general aceptable con los resultados preliminares, 2) argumentos para considerar válida la hipótesis de una estructura con simetría bidimensional en Marambio, 3) evidencias de una estructura de mayor complejidad en Matienz .In this paper antarctic magnetotelluric data obtained near the argentine bases Marambio and Matienzo were analyzed. Previous preliminary interpretation had been already published. The here presented complementary analysis put emphasis on the calculus of the elements of the impedance tensor, the more general description of the induction in earth phenomena. The conclusions of this analysis are: 1) There is a general agreement with preliminary results, 2) arguments in favour of the two dimensional structure hipothesis are obtained in the Marambio site, 3) there are evidencies of a more complex structure in the Matienzo sounding site.Asociación Argentina de Geofísicos y Geodesta

Effects of the 2021 La Palma volcanic eruption on groundwater resources (part II): Hydrochemical impacts

Volcanic eruptions can have significant implications for the management and sustainability of water resources in volcanic islands. The recent 2021 eruption of the Tajogaite volcano in La Palma Island (Canary Islands, Spain) raised concerns regarding its potential impact on groundwater resources. This study is the second part of a series investigating the hydrogeochemical impacts of the eruption. The study involved conducting three groundwater sampling campaigns during the eruption and two after the eruption, six months and one year after the eruption ceased. A total of 15 monitored points, including piezometers, wells, water galleries, and main gully collector of the island, all relatively close (2–15 km) to the erupted volcano, were sampled for the analysis of major, minor, and trace elements, physiochemical parameters, which were measured on-site. Statistical analyses were performed to assess the differences in groundwater composition before, during, and after the eruption. To evaluate the differences in water quality compared to pre-eruption events, 33 additional historical groundwater samples provided by the local Water Authority were assessed, and 103 groundwater analysis results from the groundwater data base of the Spanish National Geological Survey (IGME) were considered. The results of the study showed low but statistically significant changes in pH, T, conductivity and groundwater composition, mainly related to the high increases in several trace element concentrations, such as Al, Cr, Fe, Mo, Ni, Sr, Th, Tl, V, Zn, Ba, Cd, Co, Cu, Pb and U, with increments in various orders of magnitude for several elements. This increase was found to be highly influenced by the sample distance to the volcano during the eruption stage. The significance of these findings lies in their usefulness to enhance our understanding of the effects of volcanic eruptions on groundwater quality resources and demonstrate their resilience to this hazardous phenomenon, which ultimately underscores their reliability

Effect of chronic exercise on myocardial electrophysiological heterogeneity and stability. Role of intrinsic cholinergic neurons: A study in the isolated rabbit heart

[EN] A study has been made of the effect of chronic exercise on myocardial electrophysiological heterogeneity and stability, as well as of the role of cholinergic neurons in these changes. Determinations in hearts from untrained and trained rabbits on a treadmill were performed. The hearts were isolated and perfused. A pacing electrode and a recording multielectrode were located in the left ventricle. The parameters determined during induced VF, before and after atropine (1 mu M), were: fibrillatory cycle length (VV), ventricular functional refractory period (FRPVF), normalized energy (NE) of the fibrillatory signal and its coefficient of variation (CV), and electrical ventricular activation complexity, as an approach to myocardial heterogeneity and stability. The VV interval was longer in the trained group than in the control group both prior to atropine (78 +/- 10 vs. 68 +/- 10 ms) and after atropine (76 +/- 8 vs. 67 +/- 10 ms). Likewise, FRPVF was longer in the trained group than in the control group both prior to and after atropine (53 +/- 8 vs. 42 +/- 7 ms and 50 +/- 6 vs. 40 +/- 6 ms, respectively), and atropine did not modify FRPVF. The CV of FRPVF was lower in the trained group than in the control group prior to atropine (12.5 +/- 1.5% vs. 15.1 +/- 3.8%) and, decreased after atropine (15.1 +/- 3.8% vs. 12.2 +/- 2.4%) in the control group. The trained group showed higher NE values before (0.40 +/- 0.04 vs. 0.36 +/- 0.05) and after atropine (0.37 +/- 0.04 vs. 0.34 +/- 0.06; p = 0.08). Training decreased the CV of NE both before (23.3 +/- 2% vs. 25.2 +/- 4%; p = 0.08) and after parasympathetic blockade (22.6 +/- 1% vs. 26.1 +/- 5%). Cholinergic blockade did not modify these parameters within the control and trained groups. Activation complexity was lower in the trained than in the control animals before atropine (34 +/- 8 vs. 41 +/- 5), and increased after atropine in the control group (41 +/- 5 vs. 48 +/- 9, respectively). Thus, training decreases the intrinsic heterogeneity of the myocardium, increases electrophysiological stability, and prevents some modifications due to muscarinic block.This research was supported by the Spanish Ministry of Education and Science, (DEP2007-73234-C03-01 to AMA), http://www.mecd.gob.es/portada-mecd/; and the Generalitat Valenciana (PROMETEO 2010/093 to FJC, and FPI/2008/003 to MZ), http://www.gva.es/va/inicio/presentacion; jsessionid=ydprbDQZTsCTz85W1Such-Miquel, L.; Brines-Ferrando, L.; Alberola, A.; Zarzoso Muñoz, M.; Chorro Gasco, FJ.; Guerrero-Martínez, JF.; Parra-Giraldo, G.... (2018). Effect of chronic exercise on myocardial electrophysiological heterogeneity and stability. Role of intrinsic cholinergic neurons: A study in the isolated rabbit heart. 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N., & Quindry, J. C. (2014). Mechanisms of Exercise-Induced Cardioprotection. Physiology, 29(1), 27-38. doi:10.1152/physiol.00030.2013Hull, S. S., Vanoli, E., Adamson, P. B., Verrier, R. L., Foreman, R. D., & Schwartz, P. J. (1994). Exercise training confers anticipatory protection from sudden death during acute myocardial ischemia. Circulation, 89(2), 548-552. doi:10.1161/01.cir.89.2.548Hajnal, Á., Nagy, O., Litvai, Á., Papp, J., Parratt, J. R., & Végh, Á. (2005). Nitric oxide involvement in the delayed antiarrhythmic effect of treadmill exercise in dogs. Life Sciences, 77(16), 1960-1971. doi:10.1016/j.lfs.2005.02.015Such, L., Alberola, A. M., Such-Miquel, L., López, L., Trapero, I., Pelechano, F., … Chorro, F. J. (2008). Effects of chronic exercise on myocardial refractoriness: a study on isolated rabbit heart. Acta Physiologica, 193(4), 331-339. doi:10.1111/j.1748-1716.2008.01851.xZarzoso, M., Such-Miquel, L., Parra, G., Brines-Ferrando, L., Such, L., Chorro, F. J., … Alberola, A. (2011). The training-induced changes on automatism, conduction and myocardial refractoriness are not mediated by parasympathetic postganglionic neurons activity. European Journal of Applied Physiology, 112(6), 2185-2193. doi:10.1007/s00421-011-2189-4Billman, G. E. (2009). Cardiac autonomic neural remodeling and susceptibility to sudden cardiac death: effect of endurance exercise training. American Journal of Physiology-Heart and Circulatory Physiology, 297(4), H1171-H1193. doi:10.1152/ajpheart.00534.2009HAN, J., & MOE, G. K. (1964). Nonuniform Recovery of Excitability in Ventricular Muscle. Circulation Research, 14(1), 44-60. doi:10.1161/01.res.14.1.44Beaumont, E., Salavatian, S., Southerland, E. M., Vinet, A., Jacquemet, V., Armour, J. A., & Ardell, J. L. (2013). Network interactions within the canine intrinsic cardiac nervous system: implications for reflex control of regional cardiac function. The Journal of Physiology, 591(18), 4515-4533. doi:10.1113/jphysiol.2013.259382Armour, J. 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Aplicaciones de metodologías moleculares y biotecnológicas en la investigación sobre las enfermedades de cultivos en la Agricultura Sostenible

Las enfermedades son un componente de significación en la producción agrícola actual porque pueden reducir el rendimiento potencial o causar devastación en los cultivos de plantas; y la extensión y severidad de sus ataques va unida a los cambios que se están produciendo en los sistemas de manejo que dan lugar a mejoras en el rendimiento o modificaciones en los ambientes de producción. El control eficiente de las enfermedades requiere necesariamente la determinación exacta, rápida e informativa de su etiología, incluyendo la evaluación de la historia y potencial evolutivo en las poblaciones del agente causal, así como de la composición y diversidad de la microbiota beneficiosa asociada con el crecimiento vegetal, que hagan posible la aplicación eficiente de las acciones de prevención en que se fundamenta el manejo sostenible de dichas enfermedades. Las tecnologías de base molecular y biotecnológica ofrecen una excelente oportunidad para mejorar nuestras capacidades para satisfacer dichos requisitos. En este trabajo se ilustran tales oportunidades utilizando como ejemplo los resultados alcanzados por el Grupo AGR136 ‘Sanidad Vegetal’ durante el desarrollo de programa de investigación llevados a cabo sobre enfermedades importantes en la agricultura andaluz

Synergistic roles of climate warming and human occupation in Patagonian megafaunal extinctions during the Last Deglaciation

The causes of Late Pleistocene megafaunal extinctions (60,000 to 11,650 years ago, hereafter 60 to 11.65 ka) remain contentious, with major phases coinciding with both human arrival and climate change around the world. The Americas provide a unique opportunity to disentangle these factors as human colonization took place over a narrow time frame (~15 to 14.6 ka) but during contrasting temperature trends across each continent. Unfortunately, limited data sets in South America have so far precluded detailed comparison. We analyze genetic and radiocarbon data from 89 and 71 Patagonian megafaunal bones, respectively, more than doubling the high-quality Pleistocene megafaunal radiocarbon data sets from the region.We identify a narrowmegafaunal extinction phase 12,280 ± 110 years ago, some 1 to 3 thousand years after initial human presence in the area. Although humans arrived immediately prior to a cold phase, the Antarctic Cold Reversal stadial, megafaunal extinctions did not occur until the stadial finished and the subsequent warming phase commenced some 1 to 3 thousand years later. The increased resolution provided by the Patagonian material reveals that the sequence of climate and extinction events in North and South America were temporally inverted, but in both cases, megafaunal extinctions did not occur until human presence and climate warming coincided. Overall, metapopulation processes involving subpopulation connectivity on a continental scale appear to have been critical for megafaunal species survival of both climate change and human impacts.Fil: Metcalf, Jessica L.. University of Adelaide; Australia. State University of Colorado Boulder; Estados UnidosFil: Turney, Chris. University of New South Wales; AustraliaFil: Barnett, Ross. University of Oxford; Reino Unido. Universidad de Copenhagen; DinamarcaFil: Martin, Fabiana. Universidad de Magallanes. Instituto de la Patagonia. Centro de Estudios del Hombre Austral; ChileFil: Bray, Sarah C.. University of Adelaide; Australia. University of South Australia; AustraliaFil: Vilstrup, Julia T.. Universidad de Copenhagen; DinamarcaFil: Orlando, Ludovic. Universidad de Copenhagen; DinamarcaFil: Salas-Gismondi, Rodolfo. Université de Montpellier. Institut des Sciences de l’Evolution; Francia. Universidad Nacional Mayor de San Marcos; PerúFil: Loponte, Daniel Marcelo. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Medina, Matias Eduardo. Centro de Estudios Históricos ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: de Nigris, Mariana Eleonor. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Civalero, Maria Teresa. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fernández, Pablo Marcelo. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gasco, Alejandra Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Paleoecología Humana; ArgentinaFil: Duran, Victor Alberto. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Paleoecología Humana; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Seymour, Kevin L.. Royal Ontario Museum. Department of Natural History; CanadáFil: Otaola, Clara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Multidisciplinario de Historia y Ciencias Humanas; ArgentinaFil: Gil, Adolfo Fabian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Museo de Historia Natural de San Rafael - Ianigla | Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Museo de Historia Natural de San Rafael - Ianigla | Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Museo de Historia Natural de San Rafael - Ianigla; ArgentinaFil: Paunero, Rafael. Universidad Nacional de La Plata; ArgentinaFil: Prevosti, Francisco Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Universidad Nacional de Catamarca. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Secretaría de Industria y Minería. Servicio Geológico Minero Argentino. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja. - Provincia de La Rioja. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja; ArgentinaFil: Bradshaw, Corey J. A.. University of Adelaide; AustraliaFil: Wheeler, Jane C.. Instituto de Investigación y Desarrollo de Camélidos Sudamericanos; PerúFil: Borrero, Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Multidisciplinario de Historia y Ciencias Humanas; ArgentinaFil: Austin, Jeremy J.. University of Adelaide; AustraliaFil: Cooper, Alan. University of Adelaide; Australia. University of Oxford; Reino Unid

First emerging pollutants profile in groundwater of the volcanic active island of El Hierro (Canary Islands)

Emerging pollutants (EPs) are substances present in wastewater that have not been studied, previously, leading to ambiguity in regulations for their presence in water resources. Territories that are highly dependent on groundwater resources are at a high risk of suffering the consequences of EP contamination due to their dependence on good quality groundwater for agriculture, drinking, and other uses. A relevant example is El Hierro (Canary Islands), which was declared a biosphere reserve by the UNESCO in 2000 and is almost completely powered by renewable energies. Using high performance liquid chromatography-mass spectrometry, the concentrations of 70 EPs were assessed at 19 sampling points on El Hierro. The results indicated that no pesticides were present in groundwater; however, varied concentration levels of ultraviolet (UV) filters, UV stabilizers/blockers and pharmaceutically active compounds (PhACs) were found, with La Frontera being the most contaminated municipality. With regard to the different installation types, piezometers and wells were the ones showing the highest concentrations for most EPs. Interestingly, the depth of sampling correlated positively with EP concentration, and four different clusters virtually dividing the island into two areas could be identified based on the presence of each EP. More studies should be performed to ascertain why a few of the EPs showed considerably high concentrations at different depths. The results obtained highlight the need to, not only implement remediation measures once EPs have reached the soil and aquifers, but also to avoid their incorporation into the water cycle via homes, animal husbandry, agriculture, industry, and wastewater treatment plants (WWTPs)

Relationships with citizens in public management: a study at the largest Spanish Town Halls

This paper provides an analysis of the relationships existing between citizen participation and satisfaction levels within the framework of Spanish local administrations, additionally paying attention to the links between organisational size and the said participation and satisfaction levels. The results of a survey questionnaire answered by 388 Human Resources (HR) managers from the largest Spanish Town Halls were examined for these purposes. A claim is made both to increase the degree of citizen participation in public decision-making and to ensure the delivery of efficient and effective public services that can really meet citizens’ needs in Spanish town Halls