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The exploration and production of hydrocarbons require the management of associated aquifers not only because they must be intercepted and isolated during the drilling process, but also because they can be used as reservoirs for the final disposal of connate water, or as a source to maintain the energy of reservoirs and enhanced oil recovery operations. Despite the technological advances in the management of aquifers in the hydrocarbon industry, these kinds of operations have not been free of risks and opposition. Primary oil exploitation, improved oil recovery, and disposal of remaining water operations usually involve medium and deep aquifers that have physical, chemical, and geomechanical characteristics that may differ greatly from those known in shallow aquifers. Therefore, a detailed study of the porous media as well as the contained, produced, or reinjected fluids is an obligation for the regulation compliments and the safe handling of these operations. This chapter deals with issues associated with the chemical interaction of water, the problems that may arise from an incorrect evaluation or management, and the phenomena that can show a problem or evolution in injection operations. Finally, corrective, and preventive treatments and procedures that are commonly used in the hydrocarbon industry are specified.

To evaluate the physiological state of the wild fish inhabiting the Biobío River in South-Central Chile, susceptible to the chemical contamination from different sources, biochemical and physiological biomarkers were applied to wild fish Percilia irwini and Trichomycterus areolatus in situ. Fish caught in the Biobío river in low, medium, and high anthropic impacts areas, with different pollution degrees along the river. Ethoxyresorufin O-O deethylase (EROD) activity was evaluated in fish liver. Length, weight, Gonad weight and Liver weight, Physiological Index, and gill and liver histopathology were conducted. Physicochemical parameters (pH, Temperature, Conductivity, and TDS) were measured at each sampling site. The results indicated a deteriorating condition in the biological parameters of both species in a high anthropic zone. Fishes show an increase in physiological indices and EROD liver activity, agreeing with previous studies supporting evidence of reproductive change development as we move downstream the river. Also, an increase in histopathological lesions towards the lower third stretch of the Biobío River. The Integrated Index of Physiological Biomarkers (IPBR) indicated that sites located in the high impact area (P. irwini: BC: 4.09; RC: 3.38; PC: 3.50; SJ: 2.34 and T. areolatus BC: 6.06, PC: 5.37; SJ: 5.42) have the most detrimental environmental quality, compared to reference area. The integrated biomarker analysis demonstrates that the alterations observed are related to the high anthropic activity levels downstream from the sites with the least intervention, demonstrating that the IPBR used is a complementary tool for studies of the Environmental Effects Monitoring approach.

Background Vibrio species display variable and plastic fitness strategies to survive and interact with multiple hosts, including marine aquaculture species that are severely affected by pathogenic Vibrios. The culturable Vibrio sp. strain ArtGut-C1, the focus of this study, provides new evidence of such phenotypic plasticity as it accumulates polyhydroxybutyrate (PHB), a biodegradable polymer with anti-pathogen activity, particularly in the marine larviculture phase. The strain was isolated from the gut of laboratory-reared Artemia individuals, the live diet and PHB carrier used in larviculture. Its main phenotypic properties, taxonomic status and genomic properties are reported based on the whole-genome sequencing. Results Vibrio sp. ArtGut-C1 yielded 72.6% PHB of cells’ dry weight at 25°C. The genomic average nucleotide identity (ANI) shows it is closely related to V. diabolicus (ANI: 88.6%). Its genome contains 5,236,997-bp with 44.8% GC content, 3,710 protein-coding sequences, 96 RNA, 9 PHB genes functionally related to PHB metabolic pathways, and several genes linked to competing and colonizing abilities. Conclusions This culturable PHB-accumulating Vibrio strain shows high genomic and phenotypic variability. It may be used as a natural pathogen biocontrol in the marine hatchery and as a potential cell factory for PHB production. How to cite: Yevenes M, Quiroz M, Maruyama F, et al. Vibrio sp. ArtGut-C1, a polyhydroxybutyrate producer isolated from the gut of the aquaculture live diet Artemia (Crustacea). Electron J Biotechnol 2021;49. https://doi.org/10.1016/j.ejbt.2020.10.003

Project: Environmental isotope applications in Latin America and the Caribbean region This Special Issue illustrates the use of environmental isotopes in studying and assessing hydrogeological and ecohydrological issues in the Latin America and the Caribbean (LAC) region. The issue includes twenty selected papers, which have been peer-reviewed in Isotopes in Environmental and Health Studies. Although the LAC region concentrates a third of the world’s freshwater resources [1], access to safe water supplies and sanitation remains unevenly distributed, with water scarcity affecting most arid and semiarid areas and serious water quality issues across the region [2]. About 82% of the LAC population lives in urban centres, including some megacities, creating major challenges to water authorities [3]. Water security is often compromised due to a fast-growing water demand near urban centres (i.e. domestic supply, irrigation and industrial uses) along with the expected impacts of climate change [4] on both water availability and quality [5–7]. In many parts of the LAC region, groundwater resources have become the main or the only source of water to cover basic human needs and the maintenance of ecosystems [8–10]. This rapid increase of water demand is generally translated into intensive and unsustainable exploitation of water resources, having a profound impact on local hydrological cycles. In order to assess the availability of local resources for the near future and adopt sustainable management practices, sound and precise hydrological information is required. Este número especial ilustra el uso de isótopos ambientales en el estudio y evaluación de problemas hidrogeológicos y ecohidrológicos en la región de América Latina y el Caribe (ALC). El número incluye veinte artículos seleccionados, que han sido revisados ​​por pares en Isotopes in Environmental and Health Studies. Aunque la región de ALC concentra un tercio de los recursos de agua dulce del mundo [1], el acceso al suministro de agua potable y al saneamiento sigue distribuido de manera desigual, con la escasez de agua que afecta a la mayoría de las áreas áridas y semiáridas y graves problemas de calidad del agua en toda la región [2]. Aproximadamente el 82% de la población de ALC vive en centros urbanos, incluidas algunas megaciudades, lo que crea grandes desafíos para las autoridades del agua [3]. La seguridad hídrica a menudo se ve comprometida debido al rápido crecimiento de la demanda de agua cerca de los centros urbanos (es decir, el suministro doméstico, el riego y los usos industriales) junto con los impactos esperados del cambio climático [4] tanto en la disponibilidad como en la calidad del agua [5-7]. En muchas partes de la región de ALC, los recursos hídricos subterráneos se han convertido en la principal o única fuente de agua para cubrir las necesidades humanas básicas y el mantenimiento de los ecosistemas [8-10]. Este rápido aumento de la demanda de agua se traduce generalmente en una explotación intensiva e insostenible de los recursos hídricos, con un profundo impacto en los ciclos hidrológicos locales. Para evaluar la disponibilidad de recursos locales para el futuro cercano y adoptar prácticas de gestión sostenible, se requiere información hidrológica sólida y precisa. Universidad Nacional, Costa Rica Escuela de Química

The mid-latitude coastal area at the western South-Atlantic out of the tropics is under the combined effect of different atmospheric circulation patterns at different temporal scales, which can be ...

El objetivo del trabajo es identificar las zonas de erosion y sedimentacion costera y, cuantificar las tasas de perdida y aporte de sedimentos en un sistema playa-duna del litoral atlantico bonaerense (Argentina) a partir de un marco metodologico basado en SIG. Se realizaron 7 campanas de relevamiento topografico de marzo del 2016 a marzo del 2017.El volumen total de arena movilizada fluctuo entre 31079 y 77680 m3. Se cuantifico un area de permanente erosion de 488 m2, proxima a la linea de costa, y, un area total de 2468 m2 de permanente acumulacion coincidente en general con las crestas de los medanos. Los resultados identificaron zonas prioritarias (3,7 %) para instalar dispositivos de acumulacion de arena como posibles alternativas de remediacion de la cadena medanosa frontal, recomendandose principalmente entre marzo y junio ya que en estos meses se presentan los mayores volumenes de sedimentos en el sistema.

Recharge environmental conditions and residence time, can be studied by the application of different tracers. Several tracers are useful as proxies of the environmental recharge conditions, such as water stable isotopes deuterium and oxygen-18, and the dissolved noble gases. Other tracers are applied in order to know when the recharge occurred. Carbon-14 dating is a widely applied method for dating old groundwater, having an application range up to around 30 ky. Noble gases, as non-reactive and water-soluble substances, constitute useful tracers for studying different processes in hydrologic cycles. One of the applications is dating very old groundwater beyond the range of 14C. It can be done in a semi-quantitative way by the accumulation of 4He, and quantitatively through the radionuclide 81Kr (t1/2 = 229,000 y), a more robust method for dating groundwater up to 1.3 million years.The province of Buenos Aires, Argentina, hosts three deep sedimentary basins, from north to south, Salado, Claromecó and Colorado, with areas of 85,000 km2, 3,100 km2 and 125,000 km2, respectively. In these basins, a thick continental sequence of Neogene sediments contains confined thermal aquifers, at depths from hundreds meters to more than 1 km. The recharge conditions and the water age of the Neogene aquifers are studied through water stable isotopes, 4He and 81Kr tracers. 10 deep wells were sampled for δ2H, δ18O, 3H, 14C, for noble gases using clamped copper tubes, and for 81Kr with a gas extractor. 4He analyses were performed at the IAEA laboratory by mass spectrometry, and 81Kr at the ATTA laboratory of USTC.3H contents were not detectable in all of the cases, thus no young water components exist. By plotting the isotopic results in a δ2H vs δ18O diagram, four groups of samples can be recognized. Group 1 includes Colorado basin isotopically depleted samples (δ18O from -6.5 to -7.5 ‰) along a line parallel to the GMWL and the present LMWL, but with a higher deuterium-excess (d). Samples in G1 have a Ne/He ratio around 0.6. 14C and 81Kr ages were from 10 ky to 40 ky. Group 2 includes the samples of the borders of the Salado basin, being isotopically more enriched (δ18O from -3 to -4.5 ‰) and with a lower d than present precipitation, a Ne/He ratio from 0.2 to 0.8 and one sample with 81Kr age of 640 ky. Group 3 is formed by brines from the Colorado basin, a Ne/He ratio in the range of 1E-02 to 1E-04, and 81Kr in ages around 900 ky, and are along a line of slope 1.9, showing a 18O shift. Finally the Group 4 formed by samples at the axis of Salado basin, are isotopically enriched (δ18O from -0.5 to -3.7 ‰) along a line of slope 3.9 resembling and evaporation line. However, these samples of 81Kr ages of 1000 ky and Ne/He ratio of 2E-03, showed a high correlation Cl- vs δ18O, with increasing values from West to East. This suggest a mixing with a brine or an increasing water-rock interaction.

Fluxes between fractured-karstified and detritic aquifers are commonly poorly understood in many environments. These two types of aquifers are in contact in the southeastern Pampean region in the Argentine Buenos Aires province, and the aim of this work is to analyze their relationship contributing to improve the hydrological model. A joint application of hydrochemical and multi-isotope (δ2H, δ18O, δ13C-TDIC, δ18O-TDIC, 87Sr/86Sr) tools was used. TDIC, δ2H, δ18O and δ13C-TDIC allowed differentiating two main end members. Water in the Pampeano aquifer (PA) which is transferred from the fractured-karstic aquifer (F-KA) is characterised by high TDIC around 500–700 mg/L, isotopically depleted in 18O (about −5.5 ‰) and high δ13C-TDIC (around −10.0 ‰). The other end member is direct recharge water infiltrated into the PA with TDIC ranging from 400 to 500 mg/L, slightly enriched in 18O (δ18O = −4.8 ‰), and δ13C-TDIC in the range of soil CO2 as a result of reactions with calcrete concretions (from −20.0 to −9.0 ‰). Dolomite dissolution is the main process controlling the chemistry of the low-mineralized (Mg–Ca-HCO3) waters, whereas high-mineralized (Na-HCO3) waters are strongly influenced by ion-exchange reactions with adsorbed Ca2+ and Mg2+ and by evaporation.

The estimation of lake hydrological characteristics such as evaporation/inflow ratios and water residence time becomes necessary for understanding cycling and potential retention of natural and anthropogenic substances into the lake. The aim of this work was to estimate the evaporation loss and the water residence time of a temperate shallow lake based on the water isotope mass balance approach. One representative freshwater temperate shallow lake from the Argentinian Pampa Plain was selected. Groundwater, lake and stream samples (

The Pampean Plain in Argentina is one of the most extended plain regions of the world with numerous wetland systems and very shallow lakes. Certain anomalies related to geomorphology and shallow lakes’ hydrology are particularly present in a sector of the southern Pampean Plain, specifically, in the southwestern limit of the Quequen Grande River Basin. Here, shallow lakes can be defined as upland-embedded wetlands, characterized by the lack of observable hydrological connectivity due to the absence of surface water flows. The aim of this study was to identify groundwater connectivity of Pampean shallow lakes considered as upland-embedded wetlands and classify them according to their water presence frequency over time and their water source origin based on natural tracers (18O–H2O, 2H–H2O, electrical conductivity and Cl− content). In this work, a methodological framework involving a multitemporal analysis of the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Water Index (NDWI) derived from Landsat data, in addition to field data is proposed. According to water presence frequency, shallow lakes were classified in four categories: occasionally (89.0 %), regularly (6.7 %), usually (1.9 %) and permanently (2.3 %) with water. Obtained results allowed identifying shallow lakes having low, moderate or high mineralized water due to both different evaporation degree and water sources.

Ionic liquids (ILs) with aprotic heterocyclic anions (AHAs) have been developed primarily for CO2 capture applications. However, they have also been considered for cofluid CO2/IL vapor compression refrigeration cycles and for various electrochemical applications. In all of these cases, reducing the viscosity of the IL is of primary importance. Therefore, the focus of this work is tuning the cation to produce AHA ILs with both low viscosities and low melting points. Toward this goal we have synthesized 40 AHA ILs paired with phosphonium, ammonium and imidazolium cations, as well as a number of ILs with the bis(trifluoromethylsulfonyl)imide anion to use for comparison. The azolide anions investigated were 2-cyanopyrrolide, 4-nitropyrazolide, various substituted imidazolides, 1,2,3-triazolide, and tetrazolide. Melting points, glass transition temperatures, and decomposition temperatures were measured for all ILs. Viscosities and densities were measured from 278.15 to 343.15 K and 283.15 to 353.15 K, respecti...

This paper gives an account of the design a logic-based approach for identifying potential infiltration areas in low-gradient watersheds based on remote sensing data. This methodological framework is applied in a sector of the Pampa Plain, Argentina, which has high level of agricultural activities and large demands for groundwater supplies. Potential infiltration sites are assessed as a function of two primary topics: hydrologic and soil conditions. This model shows the state of each evaluated subwatershed respecting to its potential contribution to infiltration mainly based on easily measurable and commonly used parameters: drainage density, geomorphologic units, soil media, land-cover, slope and aspect (slope orientation). Mapped outputs from the logic model displayed 42% very low-low, 16% moderate, 41% high-very high contribution to potential infiltration in the whole watershed. Subwatersheds in the upper and lower section were identified as areas with high to very high potential infiltration according to the following media features: low drainage density (

Fresh water is of vital importance and therefore, the availability of water in urban areas has been a priority objective in the world for many years. One of the greatest challenges related to any natural resource management process is to achieve the best possible compatibility between the “ideal” and the “possible” situations. Nowadays, urban water management is a key objective particularly in intermediate cities of developing countries where human and economic resources in governmental agencies are limited. So, it is necessary to count with a tool as simple as possible, in order to allow control efforts to be prioritised. The aim of this paper is to develop a hazard index (HI), in order to identify which point sources of groundwater contamination need to be more frequently controlled and to recognise public supply wells that may be threatened. This index was applied in Mar del Plata city, located in the south-east of the Buenos Aires province, Argentina. The HI was defined as a weighted sum of three variables: Potential Contamination Load (PCL), Effluent Disposal mode (ED) and the distance from the point source to groundwater supply wells or Well Protection Areas (WP). HI results for each point source showed that all buried fuel tanks, soil and stone quarries present high HI as well as 2% of the industries. On the other hand, 90% of the inventoried industries and a landfill present the lowest HI values. Some recommendations based on two strategies (mitigation or prevention) are proposed.

The urban growth of the southern neighborhoods of Mar del Plata City provoked significant changes in the groundwater balance of the loessic sequences. These regional loessic levels with a significant portion of volcanic ash layers were reported subject to fluoride and nitrate concentrations. Residential houses pump from sands located 70 m depth and withdraw the sewages to depths less than 5 m. These effects cause significant local and seasonal (summer) increments of the water table outcropping via springs at certain unconformities of the coastal cliffs. A mathematical model was applied to analyze the water level lowering at the productive levels, while there is a decrease in the quality of the upper levels subject to waste discharges. Much of this groundwater flow is concentrated in unconformities between different types of sediments. Human activities have affected the aquifer dynamics increasing the groundwater pumping rates and the return velocity of the sewages. This should be considered in the management strategies of coastal hydric resources. Fil: Isla, Federico Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Quiroz Londoño, Orlando Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Cortizo, Luis Camilo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Bioactive substances in the Biobio River Basin in Chile were examined by deploying Semi Permeable Membrane Devices (SPMDs) upstream and downstream of 4 pulp mill effluent discharges. Androgenic and estrogenic activity of SPMD extracts were then evaluated using in vitro fish sex steroid receptor binding assays. The results indicated the occurrence of estrogenic type compounds associated with one of the mill discharges. A significant correlation among the presence of these compounds, an increase in gonadosomatic index GSI and induction of hepatic EROD activity of two native fish species was observed. However, no significant presence of mature oocytes in female gonads was detected. Although EROD induction was observed in sites impacted by mill effluents, an increase of its activity occurred towards the downstream areas, suggesting other non-mill sources. More research is needed to understand the environmental changes in context of the new technological improvements in treatment systems to MBBR (Moving Bed Biofilm Reactor) recently implemented by the pulp mill industries.

The Ballenera Creek has 160 km2 being a small catchment in the Pampa Plain in Argentina. This area has been deeply modified by human action through agricultural activities. From 2013 to 2017, electrical conductivity, stable isotopes of water and nitrate concentration monitoring program were conducted. The sampling included weekly and bimonthly samples in two sites along the stream, several groundwater wells and monthly precipitation. Chemical and isotopic tracers are used to discriminate the streamflow components and to evaluate their incidence in the nitrate concentration. The easiest conceptual model for gaining streams contemplates two main elements: direct runoff and groundwater (baseflow and pre-event water). The direct runoff has the lowest electrical conductivity and 18Ow variable content. The baseflow component is characterized by the highest electrical conductivity and isotope composition quite constant. Finally, pre-event water has an intermediate electrical conductivity and isotopic content close to the rainfall-weighted average composition. The nitrate concentration obtained was in general related to the different stream stages and was a useful indicator to evaluate the fertilization in agricultural zones. Fil: Calvi, Carolina Maria Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotópica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; Argentina Fil: Dapeña, Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotópica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; Argentina Fil: Martinez, Daniel Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Quiroz Londoño, Orlando Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

This study aims to determine the wetland potential on a pixel basis on the floodplain of the Leon River: hydrology, hydrophytic vegetation and hydromorphic soils were taken into account. Field measurements and spatially explicit models were used to model surface hydrology and piezometric levels. Satellite data were used to derive inundated areas and vegetation. Existing maps from the national geographic institute (IGAC) were used to define the spatial distribution of hydromorphic soils. Special attention was paid to agricultural infrastructure, levees and diversion channels used to modify surface hydrology in order to promote plantations and cattle grazing. A total of 536 km2 meet one or more wetland conditions according to biophysical variables, but only 393 km2 were selected, using logical rules, as wetland pixels. The combination of biophysical variables to define wetland potential is discussed in terms of the spatial distribution and the implications for environmental resource management. El presente estudio tiene como fin determinar el potencial de humedales a nivel de pixel en la llanura de inundación del Río León, se consideraron aspectos de hidrología, vegetación hidrofítica y suelos hidromórficos. Se utilizaron mediciones en campo y modelos distribuidos espacialmente para modelar la hidrología superficial y los niveles piezométricos. También se utilizaron imágenes de satélite para determinar áreas inundadas y vegetación. Los mapas existentes del instituto geográfico Agustín Codazzi fueron utilizados para definir la distribución espacial de los suelos hidromórficos. Se prestó atención especial a la infraestructura agrícola, donde los diques artificiales y trasvases han sido utilizados para modificar la hidrología superficial con el fin de promover el establecimiento de plantaciones y pastoreo. Un total de 536 km2 cumplieron una o más condiciones de humedal según las variables biofísicas, pero solo 393 km2 fueron seleccionados mediante reglas lógicas como pixeles de humedal. La combinación de variables biofísicas para la definición del potencial de humedal es discutida en términos de la distribución espacial y las implicaciones para el manejo de los recursos naturales. Fil: Anaya Acevedo, Jesús Adolfo. Universidad de Medellin; Colombia Fil: Escobar Martínez, John Fernando. Universidad de Antioquia; Colombia Fil: Massone, Hector Enrique. Universidad Nacional de Mar del Plata; Argentina Fil: Booman Zugarramurdi, Gisel Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata; Argentina Fil: Quiroz Londoño, Orlando Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata; Argentina Fil: Cañón Barriga, César Camilo. Pontificia Universidad Javeriana de Cali; Colombia Fil: Montoya Jaramillo, Luis Javier. Universidad de Medellin; Colombia Fil: Palomino Ángel, Sebastián. Universidad de Medellin; Colombia

13 páginas, 6 figuras, 2 tablas, The brine shrimp Artemia (Crustacea) and a diversity of halophilic microorganisms coexist in natural brines, salterns and laboratory cultures; part of such environmental microbial diversity is represented in the gut of Artemia individuals. Bacterial diversity in these environments was assessed by 16S rRNA gene denaturing gradient gel electrophoresis (DGGE) fingerprinting. Eight natural locations in Chile, where A. franciscana or A. persimilis occur, were sampled for analysis of free-living and gutassociated bacteria in water from nature and laboratory cultures. The highest ecological diversity (Shannon’s index, H’) was found in brines, it decreased in the gut of wild and laboratory animals, and in laboratory water. Significant differences in H’ existed between brines and laboratory water, and between brines and gut of wild animals. The greatest similarity of bacterial community composition was between brines and the gut of field animals, suggesting a transient state of the gut microbiota. Sequences retrieved from DGGE patterns (n = 83) exhibited an average of 97.8 % identity with 41 bacterial genera from the phyla Proteobacteria (55.4 % of sequences match), Bacteroidetes (22.9 %), Actinobacteria (16.9 %) and Firmicutes (4.8 %). Environment-exclusive genera distribution was seen in Sphingomonas and Paenibacillus (gut of field animals), Amaricoccus and Ornithinimicrobium (gut of laboratory animals), and Hydrogenophaga (water of laboratory cultures). The reported ecological and physiological capabilities of such bacteria can help to understand Artemia adaptation to natural and laboratory conditions., Mauricio Quiroz acknowledges project FONDEF D09I1256 (Artemia), National Commission for Scientific and Technological Research (CONICYT), Chile, for support to carry out this work at the Centre for Advanced Studies of Blanes (CEAB), Girona, Spain, which is part of his Master thesis in Natural Resources at Universidad de los Lagos, Osorno. Work in Spain was supported by project DARKNESS (CGL2012-32747) from the Spanish Office of Science (MINECO) to EOC.

We show that phosphonium azolide ionic liquids of interest for CO2 capture applications react with CO2 both through the normal anion channel and, at elevated temperatures, through a previously unrecognized cation channel. The reaction is caused by an interaction between the anion and cation that allows proton transfer, and involves a phosphonium ylide intermediate. The cation reaction can be mitigated by using ammonium rather than phosphonium cations. Thus, phosphonium and ammonium cations paired with aprotic heterocyclic anions (AHAs) react with CO2 through different mechanisms at elevated temperatures. This work shows that careful consideration of both physical properties and chemical reactivity of ILs based on AHA anions is needed when designing ionic liquids for CO2 separations.

Ionic liquids (ILs) have been received significant attention in recent years due to their outstanding properties, such as negligibly small vapor pressure, high thermal stability, relatively high conductivity and wide electrochemical windows. [1-3] Especially in the electrochemical field, ILs have been intensively investigated as alternatives for common flammable and volatile organic solvents. [4] A series of novel ionic liquids based on N,N′dialkyimidazolium, alkylphosphonium and N,N′dialkylpyrrolidinium cations paired with two aprotic heterocyclic anions (AHAs) were synthesized in the present study. In addition, their corresponding lithium salts were prepared. Physicochemical and electrochemical properties of the neat ILs and their lithium salt mixtures at various concentrations were measured from 283.15K to 343.15K at atmosphere pressure. Properties investigated include density (ρ), viscosity (η), electrical conductivity (σ), melting point (Tm), and thermal decomposition temperature (Td). Generally, the densities of all the neat ILs and their mixtures with the corresponding lithium salts follow a linear relationship with temperature and decrease with increasing temperature. The densities of all the IL mixtures with lithium salts increased with increasing lithium salt concentrations. The temperature dependence of the viscosity and the electrochemical conductivity were investigated for all neat ILs and lithium salt doped ILs. The empirical Vogel-Fulcher-Tammann (VFT) equation was used to analyze the viscosity and the electrical conductivity experimental results, which gave excellent fits over the temperature range studied.

Mendoza is the province that has the largest irrigated area in Argentina where water resources depend mainly on snowmelt and glacier melting in the closed Andes Mountain. In this region the Blanco River Basin is one of the most important, covering about 300 km2 flowing from the highest peaks to Potrerillos Dam (1300 masl). The objective of this work was to make a preliminary characterization of stable isotopes in surface and groundwater, ice and snowmelt to contribute to a better understanding of the hydrologic cycle in the region, using a Los Gatos DLT-100 analyzer. Hydrochemical analyses were performed on 157 samples. The isotopic composition of rain water is more enriched than streamwater, clearly indicating that the stream recharge sources are at higher altitude. The discharge regime of the streams indicates that snowmelt is the main water origin, and considering the theoretical evolution of isotopes in meltwater, the composition of streams corresponds to the first meltwater, without fractionation. Then, it is more depleted than the original snow. The ice isotopic composition is more enriched than streamwater, indicating that snowmelt is the main recharge source. The hydrochemical results indicate the importance of geology in determining streamwater composition, which is integrated with isotopic data to achieve a better comprehension of the hydrological system. Fil: Massone, Hector Enrique. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina Fil: Martinez, Daniel Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Vich, Alberto Ismael Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina Fil: Quiroz Londoño, Orlando Mauricio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Trombotto, Dario Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina Fil: Grondona, Sebastian. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Groundwater recharge estimation is one of the major unknowns when generating both conceptual and numerical hydrogeological models. Aquifer recharge refers to water that crosses the lower limit of the non-saturated zone, reaches the aquifer and produces measureable increases in the water table level. Though several techniques currently exist to quantify this, selecting that which is most appropriate is often difficult, especially because of the need to consider the spatial-time variation, range and data reliability of each methodology. The main objective of this study is to estimate the recharge value in the unconfined detritic aquifer in the southeast province of Buenos Aires known as the Bonaire Intermountain Plains Region, using the water table fluctuation method. A northwestern portion of the intermountain plains of this province was selected as a pilot area. The results provided a total recharge value ranging from 14.4 to 18.7% of the total rainfall. This study also presents monthly recharge data and maximum specific yield values, the latter with values between 9.9 and 13.6%.

Organochlorine pesticides (OCPs) use has been restricted or forbidden in Argentina since 1998 and technical endosulfan is the last currently used OCPs on the soybean-wheat production. As they persist in soil for several years after application, OCPs constitute a source of environmental pollution. This work aims to assess OCPs contamination of groundwater (Gw) and streamwater (Sw) in the Quequen Grande River watershed from south Argentinean Pampas in relation to the hydrogeological characteristics. OCPs were analyzed in Sw, Gw, surface bottom sediments, soils and borehole cutting sediments (Cs) by gas chromatograph-electron capture detector. Pesticide distribution in Cs was dependent on the characteristic of the non-saturated zone. Leached pesticides over 3 m in Cs showed the pattern: HCHs = endosulfan > chlordanes > DDTs, and from 3 to 6 m heptachlor was the main group as a consequence of the past use of this compound in the area, mainly on potato crops. Endosulfan reaches Gw during application season as well as during flooding events while a retard effect was observed for Sw. Levels of α- and β-isomers were in certain cases above national (7 ng L−1) and international (3 ng L−1) limits for aquatic biota protection. As the endosulfan sulfate metabolite was present in Gw and Sw and due to its high toxicity, it should be considered in the establishment of water quality criteria for human and environmental protection.

J. Neurochem. (2011) 119, 78–88. Abstract The importance of copper in the CNS is well documented, but the mechanisms related to its brain functions are poorly understood. Copper is released at the synaptic cleft, where it may modulate neurotransmission. To understand the functional impact of copper on the neuronal network, we have analyzed the synaptic activity of primary rat hippocampal neurons by using different approaches including whole cell patch clamp, recording of calcium transients, immunofluorescence and western blot. Here, we show that copper produces biphasic changes in neurotransmission. When copper is acutely applied to the plate it blocks neurotransmission. Interestingly, when it is applied for 3 h to hippocampal neurons it mainly increases the frequency and amplitude of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)ergic currents (control: 0.21 ± 0.05 Hz/22.9 ± 1.3 pA; copper: 0.68 ± 0.16 Hz/30.5 ± 2.5 pA), intracellular calcium transients (control: 0.05 ± 0.013 Hz; copper: 0.11 ± 0.02 Hz) and evoked AMPA currents (control: EC50 8.3 ± 0.5 μM; copper: EC50 2.9 ± 0.2 μM). Moreover, our results suggest that copper increases GluA1 subunit levels of the AMPA receptor through the anchorage of AMPA receptors to the plasma membrane as a result of PSD-95 accumulation. We also found that copper-treated neurons displayed an undistinguishable neurotransmission to control neurons after 24 h of treatment, indicating that changes in neurotransmission induced by copper at 3 h of incubation are homeostatically regulated after long-term exposure to the metal. Together, our data reveal an unexpected biphasic effect of copper on neurotransmission, which may be relevant to understand the effects of this ion in brain diseases that display copper dyshomeostasis such as that observed in Alzheimer’s disease (AD).

3,3′,5,5′-Tetrasubstituted-2,2′-biphenolate complexes of titanium(IV) with bis(diketonate) (Bob), bis(hydroxamate) (Hox) and mixed diketonate–hydroxamate (Hob) ligands have been prepared from the corresponding diisopropoxide complexes. Four of the twelve compounds have been characterized crystallographically, and in the solid state all show the (Δ,R)/(Λ,S) relative stereochemistry at titanium and the biaryloxide, respectively, as previously observed in (acac)2Ti(1,1′-bi-2-naphtholate) complexes. In solution the compounds epimerize by atropisomerization of the biphenolate moiety with ΔG‡ ≈ 14 kcal mol−1. The bis(diketonate) complexes show high diastereoselectivity except for the most electron-poor tetranitrobiphenolate. In contrast, the bis(hydroxamate) shows low to moderate selectivity which correlates with the steric but not electronic properties of the biphenolates (Br < CH3 < NO2 < tBu). The mixed diketonate–hydroxamate complexes show intermediate behaviour. These observations are rationalized on the basis of MO arguments regarding ligand-metal π bonding. Symmetrical chelates such as diketonates foster mixing of two dπ orbitals and create a dissymmetric electronic environment. This mixing does not take place with unsymmetrical ligands such as hydroxamates, which therefore do not create an environment where electronic effects contribute significantly to binding stereoselectivity.

The Negro River extends from the Andes to the Atlantic Ocean supplying water to several cities and to the most important fruit-bearing productive region of Patagonia. Floodplains from the Upper Valley are artificially irrigated with water delivered from the main channel. Pesticides are increasingly used without strict government control. Dams constructed at the tributary rivers retain sediment and therefore the clean water delivered becomes free of sediment and therefore is able to erode certain levees during high-discharge events. Bedload–transport fraction (sand dunes) increases at the Upper Valley and is fixed at the levees of the Lower Valley by riparian vegetation. This riparian vegetation is dominated by Salix humboldtiana and Schoenoplectus californicus while Spartina sp is abundant at the estuarine marsh area. Organochlorine compounds (OCCs) were measured by GC-ECD including dichloro-diphenyl-trichloroethane (DDT), dichlorophenyl-dichloroethylene (DDE) and dichloro-dyphenyl-dichloroethane (DDD) en...

The southeast area of the Argentine Pampas is characterized by the presence of an unconfined aquifer in a wide plain. A methodology is proposed that deals with the aquifer vulnerability where the homogeneity of the hydrogeological variables used by traditional methods (in this case, DRASTIC-P) causes vulnerability maps to show more than 80% of the territory under the same class. This absence of discrimination renders vulnerability maps of little use to decision-makers. In addition, the proposed methodology avoids the traditional vague classification (high, low, and moderate vulnerability) which is highly dependent on subjectivity in its association of each class with hydrogeological considerations. That traditional vulnerability assessment methodology was adapted using a geographic information system to reclassify classes, based on the Natural Breaks (Jenks) method. The pixel-to-pixel comparison between the result obtained by the DRASTIC-P and the reclassified classes generates the so-called operational vulnerability index (OVI), which shows four classes, associating each with different hydrogeological requirements to make decisions. El área sudeste de las Pampas de Argentina está caracterizada por la presencia de un acuífero no confinado en una amplia llanura. Se propone una metodología que trata la vulnerabilidad del acuífero donde la homogeneidad de las variables hidrogeológicas usadas por los métodos tradicionales (en este caso, DRASTIC-P) produce mapas de vulnerabilidad que muestran más del 80% de territorio bajo la misma clase. Esta ausencia de discriminación da mapas de vulnerabilidad de poca utilidad para los tomadores de decisiones. Además, la metodología propuesta evita la clasificación ambigua tradicional (vulneralidad alta, baja y moderada) que es altamente dependiente de la subjetividad en su asociación de cada clase con consideraciones hidrogeológicas. Esta metodología tradicional de evaluación de la vulnerabilidad fue adaptada usando un sistema de información geográfica para reclasificar clases, basado en el método Natural Breaks (Jenks). La comparación pixel a pixel entre los resultados obtenidos por DRASTIC-P y el de las clases reclasificadas genera, los así llamados índices de vulnerabilidad operacional (OVI), que muestran cuatro clases, asociando cada una con diferentes requerimientos hidrogeológicos para la toma de decisiones. A região sudeste das Pampas Argentinas é caracterizada pela presença de um aquífero livre numa ampla planície. Propõe-se uma metodologia para calcular a vulnerabilidade do aquífero quando a homogeneidade das variáveis hidrogeológicas usadas pelos métodos tradicionais (como DRASTIC-P) fazem com que os mapas de vulnerabilidade mostrem que mais de 80% do território ficam sob a mesma classe. Esta ausência de discriminação torna os mapas de vulnerabilidade de pouca utilidade para os decisores. Adicionalmente, a metodologia proposta evita a tradicional classificação vaga (vulnerabilidade alta, moderada e baixa), a qual é extremamente dependente da subjectividade, pela associação de cada classe a considerações hidrogeológicas. A metodologia tradicional de avaliação de vulnerabilidade foi adaptada, tendo para o efeito sido utilizado um sistema de informação geográfica para reclassificar as classes, com base no método das quebras naturais de Jenks (Jenks’ Natural Breaks). A comparação pixel-a-pixel entre o resultado obtido com DRASTIC-P e com as classes reclassificadas dá origem a um designado índice de vulnerabilidade operacional (operational vulnerability index, OVI) que mostra quatro classes, associando-se cada uma delas a diferentes requisitos hidrogeológicos necessários para a tomada de decisões. Fil: Massone, Héctor. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Quiroz Londoño, Orlando Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina Fil: Martinez, Daniel Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentina

The synthesis, complete characterization, and solid state conformation of a new series of p-tert-butylcalix[5]arene (ButC5) mono-, di-, tri- and pentaanions are reported. X-ray structures of the alkali metal salts illustrate the strong influence of the alkali metal ion on the structure of the calixanion. The strength of the alkali metal base and its reaction stoichiometry play an important role in the conformation and level of deprotonation of the resulting anion. Reaction of ButC5 in a 2:1 molar ratio with alkali metal bases M2CO3 (M = Rb, Cs), or in a 1:1 ratio with M2CO3 (M = Na, K), MOH (M = Na, K, Rb, Cs) or MH (M = Li, Na) produces ButC5 monoanions, but ButC5 reacts in a 1:1 molar ratio with M2CO3 (M = Rb, Cs) or a 1:2 molar ratio with MOC(CH3)3 (M = Na, K) to afford ButC5 dianions. Due to the steric bulkiness of the But group no polymeric structures are observed. Alkali metal salts of trianionic ButC5 were obtained in high yields from reactions of ButC5 with MOC(CH3)3 (M = Li, Na, K), BunLi, LiH and LiOH in a 1:3 molar ratio. Pentaanionic ButC5 salts were obtained by the reaction with MOC(CH3)3 (M = Li, Na, K) or BunLi in a 5:1 ratio. X-ray crystal structures of ButC5 · Na and ButC5 · Cs indicate that the size of the alkali metal influences the level of cation-π arene interactions and therefore the conformation of the ButC5 unit; for example, ButC5 · Na has a cone conformation while ButC5 · Cs shows a flattened cone conformation. Cation-π arene interactions are observed in most of the calixarene salts.

Stable isotopes and electrical conductivity in groundwater were used as natural tracers to adjust the hydrogeological conceptual model in one of the largest catchments within the inter-mountainous Pampa plain, Argentina. Geostatistical tools were used to define the model that best fitted the spatial distribution of each tracer, and information was obtained in areas where there was a lack of data. The conventional isotopic analysis allowed the identification of three groundwater groups with different isotopic fingerprints. One group containing 56 % of the total groundwater samples suggested a well-mixed system and soil infiltration precipitation as the main recharge source to the aquifer. The other two groups included samples with depleted (25.5 %) and enriched (18.5 %) isotopic compositions, respectively. The combination of δ18O, δ2H and electrical conductivities maps suggested ascending regional flows and water transfer from the Quequén Grande River catchment to the Moro creek. The spatial interpretation of these tracers modified the conceptual hydrogeological model of the Quequén Grande River. Fil: Quiroz Londoño, Orlando Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina Fil: Martinez, Daniel Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina Fil: Massone, Hector Enrique. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina Fil: Londoño Ciro, Libardo Antonio. Universidad de Antioquia; Colombia Fil: Dapeña, Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotópica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; Argentina

Ionic liquids (ILs) with aprotic heterocyclic anions, or AHAs, can bind CO2 with reaction enthalpies that are suitable for gas separations and without suffering large viscosity increases. In the present work, we have synthesized ILs bearing an alkyl-phosphonium cation with indazolide, imidazolide, pyrrolide, pyrazolide and triazolide-based anions that span a wide range of predicted reaction enthalpies with CO2. Each AHA-based IL was characterized by NMR spectroscopy and their physical properties (viscosity, glass transition, and thermal decomposition temperature) determined. In addition, the influence of substituent groups on the reaction enthalpy was investigated by measuring the CO2 solubility in each IL at pressures between 0 and 1 bar at 22 °C using a volumetric method. The isotherm-derived enthalpies range between -37 and -54 kJ mol(-1) of CO2, and these values are in good agreement with computed enthalpies of gas-phase IL-CO2 reaction products from molecular electronic structure calculations. The AHA ILs show no substantial increase in viscosity when fully saturated with CO2 at 1 bar. Phase splitting and compositional analysis of one of the IL/H2O and IL/H2O/CO2 systems conclude that protonation of the 2-cyanopyrrolide anion is improbable, and this result was confirmed by the equimolar CO2 absorption in the presence of water. Taking advantage of the tunable binding energy and absence of viscosity increase after the reaction with CO2, AHA ILs are promising candidates for efficient and environmental-friendly absorbents in postcombustion CO2 capture.

This paper gives an account of the implementation of hydrochemical and isotopic techniques to identify and explain the processes that govern solute exchange in two groundwater-dependent shallow lakes in the Southeastern Pampa Plain of Argentina. Water samples (lakes, streams, spring water and groundwater) for hydrochemical and stable isotopic determination were collected and the main physical-chemical parameters were measured. The combination of stable isotope data with hydrogeochemical techniques was used for the identification of sources and preferential recharge areas to these aquatic ecosystems which allowed the explanation of the lake water origin. The hydrochemical processes which explain Los Padres Lake water chemistry are evaporation from groundwater, CO2 input, calcite dissolution, Na+ release by Ca2+ and Mg2+ exchange, and sulfate reduction. The model that best aligns with La Brava Lake hydrochemical constraints includes: mixing, CO2 and calcite dissolution, cationic exchange with Na+ release and Mg2+ adsorption, and to a lesser extent, Ca/Na exchange. This model suggests that the fractured aquifer contribution to this water body is greater than 50 %. An isotopic-specific fingerprint for each lake was identified, finding a higher evaporation rate for La Brava Lake compared to Los Padres Lake. Isotopic data demonstrate the importance of these shallow lakes as recharge areas to the regional aquifer, becoming areas of high groundwater vulnerability. The Tandilia Range System, considered in many hydrogeological studies as the impermeable bedrock of the Pampean aquifer, acts as a fissured aquifer in this area, contributing to low salinity waters and with a fingerprint similar to groundwater isotopic composition. Fil: Romanelli, Asunción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina Fil: Quiroz Londoño, Orlando Mauricio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Martinez, Daniel Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Massone, Hector Enrique. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina Fil: Escalante, Alicia Haydee. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

The importance of copper in the CNS is well documented, but the mechanisms related to its brain functions are poorly understood. Copper is released at the synaptic cleft, where it may modulate neurotransmission. To understand the functional impact of copper on the neuronal network, we have analyzed the synaptic activity of primary rat hippocampal neurons by using different approaches including whole cell patch clamp, recording of calcium transients, immunofluorescence and western blot. Here, we show that copper produces biphasic changes in neurotransmission. When copper is acutely applied to the plate it blocks neurotransmission. Interestingly, when it is applied for 3 h to hippocampal neurons it mainly increases the frequency and amplitude of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)ergic currents (control: 0.21 ± 0.05 Hz/22.9 ± 1.3 pA; copper: 0.68 ± 0.16 Hz/30.5 ± 2.5 pA), intracellular calcium transients (control: 0.05 ± 0.013 Hz; copper: 0.11 ± 0.02 Hz) and evoked AMPA currents (control: EC50 8.3 ± 0.5 μM; copper: EC50 2.9 ± 0.2 μM). Moreover, our results suggest that copper increases GluA1 subunit levels of the AMPA receptor through the anchorage of AMPA receptors to the plasma membrane as a result of PSD-95 accumulation. We also found that copper-treated neurons displayed an undistinguishable neurotransmission to control neurons after 24 h of treatment, indicating that changes in neurotransmission induced by copper at 3 h of incubation are homeostatically regulated after long-term exposure to the metal. Together, our data reveal an unexpected biphasic effect of copper on neurotransmission, which may be relevant to understand the effects of this ion in brain diseases that display copper dyshomeostasis such as that observed in Alzheimer's disease (AD).

The Pampa in Argentina is a large plain with a quite obvious dependence on agriculture, water availability and its quality. It is a sensitive environment due to weather changes and slope variations. Supplementary irrigation is a useful practice for compensating the production in the zone. However, potential negative impacts of this type of irrigation in salinization and sodification of soils are evident. Most conventional methodologies for assessing water irrigation quality have difficulties in their application in the region because they do not adjust to the defined assumptions for them. Consequently, a new GIS-based methodology integrating multiparametric data was proposed for evaluating and delineating groundwater suitability zones for irrigation purposes in flat areas. Hydrogeological surveys including water level measurements, groundwater samples for chemical analysis and electrical conductivity (EC) measurements were performed. The combination of EC, sodium adsorption ratio, residual sodium carbonate, slopes and hydraulic gradient parameters generated an irrigation water index (IWI). With the integration of the IWI 1 to 3 classes (categories of suitable waters for irrigation) and the aquifer thickness the restricted irrigation water index (RIWI) was obtained. The IWI′s index application showed that 61.3 % of the area has “Very high” to “Moderate” potential for irrigation, while the 31.4 % of it has unsuitable waters. Approximately, 46 % of the tested area has high suitability for irrigation and moderate groundwater availability. This proposed methodology has advantages over traditional methods because it allows for better discrimination in homogeneous areas.

Both the radical cation tris(4-bromophenyl)aminium hexachloridoantimonate ('Magic Blue'), (C(18)H(12)Br(3)N)[SbCl(6)], (I), and neutral tris(4-bromophenyl)amine, C(18)H(12)Br(3)N, (II), show extremely similar three-bladed propeller structures with planar N atoms. Key geometric features, such as the C-N bond distances and the angles between the planes of the aryl groups and the central NC(3) plane, are identical within experimental uncertainty in the two structures. This contrasts with the significant structural changes observed on oxidation of more electron-rich triarylamines, where resonance contributes to the stabilization of the radical cation, and suggests that, in general, more strongly oxidizing triarylaminium cations will have lower inner-sphere reorganization energies than their lower-potential analogues.

Comprender el funcionamiento hidrológico y la interacción de los diferentes cuerpos de agua en un área específica es un tema esencial a la hora de planificar el uso racional del recurso hídrico. El objetivo de este trabajo es realizar un aporte en el ámbito metodológico, al evaluar la aplicación conjunta de métodos hidrológicos-limnológicos y de SIG en el estudio de lagos someros, y profundizar en el conocimiento del comportamiento hidrológico de los humedales en ambientes de llanura, tomando como área piloto la laguna La Salada en la Llanura Interserrana Bonaerense. La misma es una laguna somera, permanente y arreica con una extensión de 5,78 km2. En este trabajo se aplican metodologías y herramientas ofrecidas por los SIG para establecer la evolución y el estado de este humedal. Utilizando el Modelo Digital de Terreno del área, se elaboraron perfiles topográficos que muestran la relación entre esta laguna y los cuerpos de agua cercanos, y se realizó el análisis multitemporal de los parámetros morfométricos. Se diseñó una malla de muestreo para establecer la batimetría de la laguna y realizar su caracterización hidrogeoquímica e isotópica. Su composición química es homogénea tanto arealmente como en profundidad. Una variación de conductividad en profundidad, el contenido isotópico y el diagrama de Gibbs, sugieren que un proceso de evaporación domina la química del agua. Los parámetros físico- químicos permitieron establecer la aptitud del agua para distintos usos.

New sterically encumbered tripodal aminetris(aryloxide) ligands N(CH(2)C(6)H(2)-3-(t)Bu-5-X-2-OH)(3) ((tBu,X)LH(3)) with relatively electron-rich phenols are prepared by Mannich condensation (X = OCH(3)) or by a reductive amination/Hartwig-Buchwald amination sequence on the benzyl-protected bromosalicylaldehyde (X = N[C(6)H(4)-p-OCH(3)](2)), followed by debenzylation using Pearlman's catalyst (Pd(OH)(2)/C). The analogous dianisylamino-substituted compound lacking the tert-butyl group ortho to the phenol ((H,An(2)N)LH(3)) is also readily prepared. The ligands are metalated by titanium(IV) tert-butoxide to form the five-coordinate alkoxides LTi(O(t)Bu). Treatment of the tert-butoxides with aqueous HCl yields the five-coordinate chlorides LTiCl, and with acetylacetone gives the six-coordinate diketonates LTi(acac). The diketonate complexes (tBu,X)LTi(acac) show reversible ligand-based oxidations with first oxidation potentials of +0.57, +0.33, and -0.09 V (vs ferrocene/ferrocenium) for X = (t)Bu, MeO, and An(2)N, respectively. Both dianisylamine-substituted complexes (R,An(2)N)LTi(acac) (R = (t)Bu, H) show similar electrochemistry, with three one-electron oxidations closely spaced at approximately 0 V and three oxidations due to removal of a second electron from each diarylaminoaryloxide arm at approximately + 0.75 V. The new electron-rich tripodal ligands therefore have the capacity to release multiple electrons at unusually low potentials for aryloxide groups.