Diagnóstico y tratamiento de la esofagitis eosinofílica en niños. Revisión de la literatura y recomendaciones basadas en la evidencia. Grupo de trabajo de la Sociedad Latinoamericana de Gastroenterología, Hepatología y Nutrición pediátrica (SLAGHNP).

During the last twenty years Eosinophilic Esophagitis has become one the most important causes of esophageal disfunction in children, food impactation in adolescents and young adults, therapeutic failure in patients with gastroesophageal reflux disease (GERD) and the most frecuent eosinophilic disease of the gastrointestinal tract. We present recommendations for the diagnosis and treatment of the disease based in a systematic review of the literature.

Impact of rainfed agriculture on spatio-temporal patterns of water balance and the interaction between groundwater and surface water in sub-humid plains.

The expansion of rainfed agriculture, especially soybean cultivation in sub-humid plains, alters water balance and the exchange between groundwater-surface water (GW-SW). However, to date, there are no studies that analyze how these anthropic disturbances affect hydrological connectivity in these systems, especially the GW-SW interactions. The objective of this study is to analyze how the increase in rainfed agriculture affects the spatio-temporal patterns of the water balance and the GW-SW interaction. For this analysis, a coupled GW-SW flow model was implemented under land use and land cover (LULC) scenarios, to quantify the spatio-temporal dynamics for different components of water balance and GW-SW interactions for the upper creek basin of Del Azul. A simulation was carried out for a period of 13 years (2003-2015) on a daily scale and it was contrasted through three multitemporal LULC maps. The results point that substitution of natural pastures, the reduction of winter crops and the decrease of crop rotation, due to the increase of soybean monoculture in the basin under study, modifies the water balance, especially the annual rates of surface runoff and soil moisture which may increase between 3.5 and 9.4 % and between 1.4 and 4.4 % respectively, thus increasing the annual streamflows between 2.6 and 6.8 % and the groundwater heads between 0.2 and 0.6 m. This leads to changes in the hetereogeneity of the GW-SW interaction, a reduction between 0.3 and 3 % is observed in the discharge from the Pampeano aquifer to the Del Azul stream, while the recharge rates from the Del Azul stream to the Pampeano aquifer increase between 2 and 17.8 %. The application of the SWAT-MODFLOW model under LULC scenarios, improves the prediction of the regional hydrologic connectivity on sub-humid plains, because the hydrological processes occurring in the surface and non-saturated zone are governed by shallow groundwater dynamics.

Spatio-temporal effect of climate change on water balance and interactions between groundwater and surface water in plains.

The analysis of the impact of climate change on water resources in plains requires integral simulation tools that quantify topographic complexity and the strong interaction of groundwater and surface water components (GW-SW). The objective of this study is to implement a coupled hydrological-hydrogeological model under climate change scenarios in order to quantify the spatio-temporal dynamics of water balance and GW-SW interactions for the upper creek basin of Del Azul, which is located in the center of the province of Buenos Aires. The simulation was carried out for a baseline scenario calibrated and validated for the period 2003-2015 and contrasted with two scenarios of the regional climate model CCSM4, RCP (4.5 and 8.5) simulated for the period 2020-2050. First, the annual and monthly anomalies of precipitation, temperature, surface runoff, evapotranspiration, soil moisture, recharge, flow, as well as the discharge, head level and reserves of groundwater are studied. Then the spatio-temporal anomalies of the GW-SW interaction were analyzed and finally wet and dry periods by means of the standardized precipitation index and the annual water balance were studied. Simulation results show that climate change will significantly alter the spatio-temporal patterns of the GW-SW interaction as well as the water balance. These showed monthly, seasonal and annual variations. They show an increase in most of the components of the water balance towards the middle of the 21st century, except soil moisture. Regarding GW-SW interactions, the average annual discharge of the aquifer to the stream is expected to increase by 5% with RCP 4.5 while it will increase 24% with RCP 8.5. The recharge from the stream to the aquifer is expected to increase by 12% with RCP 4.5 while a decrease by 5% with RCP 8.5. Concerning the SPI related to the water balance for the period 2020-2050, alternations of both the time and the length of dry and wet periods are expected for the two scenarios, with RCP 4.5 low frequency of wet episodes, but with a greater severity and permanence in time in contrast to RCP 8.5 that presents less frequency in dry periods, but with high permanence and severity. Climate change could alter groundwater mainly through changes in the recharge, leading to modify groundwater levels and this will cause GW-SW flow to be reversed in some sectors of the stream by increasing or decreasing groundwater discharge into the stream.

Hydrological dataset of a sub-humid continental plain basin (Buenos Aires, Argentina).

The Chaco-Pampean Plain (Argentina) is the strongest economic region and the most inhabited in the country, comprising approximately 66% of the country's population (26,500 million) [1]. In this region, surface slopes are very low (<0.1%) and due to the current climatological features, floods and droughts alternate over time. Salinity and alkalinity of water and soil increase towards the flattest sector of the basin, as well as the contents of arsenic and fluoride, which restrict their human use. Worldwide, population growth and global warming, in addition to political decisions, are leading to abrupt land use changes. Under this premise, identifying and quantifying the hydrological processes that control water quantity and its chemical quality become an imperative task [2]. This data article provides a long-term hydrological dataset from a sector of the Chaco-Pampean Plain, the Del Azul creek basin. Hydrological data such as flow rates and piezometric levels, and physical-chemical (i.e., major and minor solutes, and trace elements) and isotopic (δ18O, δ2H; and d-excess) data from rainwater, surface (creek and wetland) and groundwater (at two depths) are available. Rainwater samples are derived from three precipitation collectors installed at different altitudes (monitoring period: 2010-2019; n = 57). Surface water samples were collected at three sampling sites located along the Del Azul Creek and six wetlands (monitoring period: 2018-2019; n = 12). Groundwater samples were collected from 17 piezometers with depths ranging between 3 and 10 m, and from 12 piezometers of 30 m depth, all located throughout the entire basin (monitoring period: 2018-2019; n = 115). Sampling campaigns were performed during the austral dry (summer) and wet (spring) seasons. This dataset provides useful information to understand a) how water moves from recharge to discharge areas, b) how water acquires salinity, and c) how particular solutes of concern, such as arsenic and fluoride, are distributed in space and time across in an extensive plain.

Using isotope data to characterize and date groundwater in the southern sector of the Guaraní Aquifer System.

The Guaraní Aquifer System (SAG) is the largest transboundary aquifer in Latin America, extending beneath parts of Brazil, Paraguay, Argentina, and Uruguay. This paper presents the results of recent hydrogeological studies in the southern portion of the SAG. Locally, the abundance of surface water bodies precluded the use of conventional hydrological tools to characterize groundwater flows. Geological, hydrochemical and environmental isotope investigations were integrated to postulate a revised hydrogeological conceptual model. The revised geological model has provided a better definition of the geometry of the aquifer units and outlined the relevance of regional faults in controlling flow patterns. The new potentiometric map is consistent with groundwater flow from the SAG outcrops to the centre of the Corrientes Province, where upwards flows were identified. Hydrochemical and isotope data confirmed the widespread occurrence of mixing. Noble gas isotopes dissolved in groundwater (4He and 81Kr/Kr) provided residence times ranging from recent recharge up to 770 ± 130 ka. Groundwater age modelling confirmed the role of the geological structures in controlling groundwater flow. The southern sector of the SAG is a multilayer aquifer system with vertical flows and deep regional discharge near the Esteros del Iberá wetland area and along the Paraná and Uruguay rivers.