ALBERT

Description: 〈h3〉Abstract〈/h3〉 〈p〉A single-well push–pull test is one of the most effective ways to estimate aquifer transport parameters. However, a patchy aquifer of finite thickness may surround the test well due to a gravel pack, mud invasion and stress redistribution during the well construction, which is usually neglected for single-well push–pull tests. In such a case, the aquifer should be regarded as a radial two-zone system, i.e., patchy zone and aquifer formation zone. In this study, a numerical model of a single-well push–pull test for a radial two-zone confined aquifer was developed using finite-element COMSOL Multiphysics. Two special cases, i.e., uniform patchy aquifer and non-uniform patchy aquifer, were considered. For the uniform patchy aquifer, results indicate that larger values of effective porosity and dispersivity in the patchy zone results in larger values of the breakthrough curves in the pumping phase. Patchy-aquifer thickness was also noted to have considerable impact on the breakthrough curves. As for the nonuniform patchy aquifer, the variation of hydraulic conductivity, dispersivity and effective porosity in the patchy zone leads to a change of concentration along the z-direction around the well screen, and as such, a smaller dispersivity of patchy regions results in more fluctuation in the concentration curve, while little impact can be found for a larger dispersivity. In addition, results showed that the average concentration over the entire screened section with an equivalent uniform patchy aquifer can be applied to interpret the data of a single-well push–pull test for the case of a nonuniform patchy aquifer.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Mexico City aquifer is a complex mix of alluvial deposits and volcanic rocks overlapped by an aquitard composed of lacustrine deposits. To characterize this heterogeneous hydrogeologic system, a three-dimensional model of the distribution of hydrofacies is constructed using borehole lithological records. The analysis is based on 111 borehole logs with an average depth of 300 m, in an area of 234 km〈sup〉2〈/sup〉, providing a nominal scale of resolution of 2.1 km in the plane and 2-m resolution in the vertical direction. These records were discretized to generate a georeferenced dataset of 13,518 points associated with a lithological category; nine lithological categories were observed. These categories were subsequently grouped into four hydrofacies: A and B, grouping low-permeability lithological categories (lacustrine and volcano-sedimentary materials, respectively); and C and D, grouping high-permeability lithological categories (volcanic rocks and alluvial deposits, respectively). The database was analyzed in terms of proportion of hydrofacies at depth, distribution of layer thickness, and behavior of experimental horizontal and vertical variograms. The experimental variograms of each hydrofacies were fitted to exponential models via minimization of cross-validation errors. Three-dimensional models of probability of occurrence of each hydrofacies and the combined distribution of hydrofacies were then constructed via ensemble averaging of 1,000 realizations obtained by sequential indicator simulation. The potential use of this model for water management, modeling land subsidence, and groundwater pollution is discussed.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Gravity Recovery and Climate Experiment (GRACE) twin satellites introduced a new opportunity to monitor changes in groundwater level. However, the performance of the GRACE-derived Liquid Water Equivalent Thickness (GRACE-LWET) in estimating groundwater-level changes at a local scale requires evaluation. Thus, the main aim of this study is to evaluate the performance of the GRACE-derived estimation in monitoring groundwater-level changes in Iran, which is experiencing decreasing trends and subsequent impacts. Another aim is to investigate the time lag between the water levels derived from the GRACE estimation and direct measurements. Four regions in Iran were studied between the years 2002 and 2016. To evaluate the results of GRACE-LWET, groundwater levels in 144 piezometric wells were measured monthly. The changes of the earth’s mass due to surface-water changes were assessed using four datasets of the Global Land Data Assimilation System. Furthermore, the statistical trend of the groundwater-level changes acquired from the GRACE estimations and observational data was investigated using the Mann-Kendall test and Sen’s slope estimator at a significance level of 0.05. The results showed that the best performance of the GRACE estimations was acquired when considering a 2-month time lag. In this case, the average correlation coefficient of the GRACE estimations against the observational data for the entire study region was 0.57. Moreover, the GRACE-LWET showed a significant decreasing trend for the whole study area using both considered tests. Hence, GRACE-derived estimation of groundwater-level changes can be used in regions with insufficient observational well data with an acceptable accuracy.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The crystalline-rock aquifer system of the Llano Uplift (Central Texas, USA) hosts an important local water resource that has been relatively little studied. The Uplift is a structural dome of Precambrian granitic and metamorphic rocks. Late Paleozoic normal faulting and fractures, decompressive fractures, weathering, lithology, and rock fabric control the aquifer properties. Data from driller reports (over 2,000 wells) show that wells in granites have higher median yields than wells in metamorphic rocks. There is a weak correlation of well yield with regolith thickness, and median regolith thickness is greater over granites than over metamorphic rocks. Fracture permeability, which is very heterogeneous, is the major control. Wells are shallow (generally 〈100 m depth), but more recent wells have been drilled more deeply. Permeability data imply decreased open-fracture density and aperture with depth, although sample bias is a consideration. Diamond drill cores show that many near-surface fractures with significant aperture are filled by rock fragments from weathered surrounding rocks and that fracture skins are thinner and contain iron oxides in a more reduced state with depth. Fracture skins can be porous, with porosity ranging to over 10%. There is a need to compare crystalline-rock aquifer systems to assess weathering, tectonics, fractures, and mineralogy/petrology to assess the characteristics of these systems, which are critical water resources in large areas of the world.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The 〈em〉Streptomyces〈/em〉 sp. strain AV05 isolated from an organic amendment was found to impact both growth and fumonisin production of 〈em〉Fusarium verticillioides〈/em〉 during in vitro direct confrontation. In order to investigate the interactions between the 〈em〉Streptomyces〈/em〉 sp. strain AV05 and 〈em〉F〈/em〉. 〈em〉verticillioides〈/em〉, a metabolomic approach was used. The study of the endometabolomes of the microorganisms was carried out in two different conditions: the microorganisms were cultivated alone or in confrontation. The aim of this study was to examine the modifications of the endometabolome of 〈em〉F〈/em〉. 〈em〉verticillioides〈/em〉 in confrontation with the 〈em〉Streptomyces〈/em〉 strain. The metabolites involved in these modifications were identified using 2D NMR. Many metabolites were found to be overproduced in confrontation assays with the 〈em〉Streptomyces〈/em〉 strain, notably 16 proteinogenic amino acids, inosine, and uridine. This suggested that fungal metabolic pathways such as protein synthesis have been affected due to interaction. Thus, metabolomic studies, as well as proteomics or transcriptomics, are useful for deciphering the mechanisms of interactions between biological control agents and mycotoxigenic fungi. This comprehension is one of the key elements of the improvement of the selection and use of antagonistic agents.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Mastitis in dairy cows is generally considered to be the most expensive disease for dairy farmers worldwide. The overuse of antibiotics is a major problem in the treatment of bovine mastitis, and bacteriophage therapy is expected to provide an alternative treatment. The primary aim of this study was to evaluate the efficacy of a phage cocktail against mastitis in a mouse model. First, a 〈em〉Staphylococcus aureus〈/em〉 strain was isolated from milk samples taken from mastitis cows from dairy farms in Xinjiang, China, and it was designated as Sau-XJ-21. Next, two phages (designated as vBSM-A1 and vBSP-A2) with strong lytic activity against Sau-XJ-21 were isolated from mixed sewage samples collected from three cattle farms in Xinjiang. Phages vBSM-A1 and vBSP-A2 were identified as members of the Myoviridae and Podoviridae families, respectively. The two phages exhibited a wide range of hosts, especially phage vBSM-A1. To evaluate the effectiveness of the two phages in the treatment against mastitis, female lactating mice were used 10–14 days after giving births. The mice were divided into six groups; one group was kept as healthy control, while the remaining five groups were inoculated with the isolated 〈em〉S. aureus〈/em〉 strain to induce mastitis. Four hours after bacterial inoculation, mice in these groups were injected with 25 μL phosphate buffer saline (negative control), ceftiofur sodium (positive control), or phage, either individually or as a cocktail. The mice were sacrificed 20 h later, and the mammary glands were removed and subjected to further analysis, including the quantitation of colony-forming units (CFU), plaque-forming units (PFU), and gross macroscopic as well as histopathology observation. Mice with induced mastitis exhibited significantly improved mastitic pathology and decreased bacterial counts after they had been given phage treatments, with the phage cocktail being more superior than either phage alone. Furthermore, the cocktail treatment also maintained the highest intramammary phage titer without spreading systemically. The effectiveness of the phage cocktail was comparable to that produced by ceftiofur sodium〈em〉.〈/em〉 According to the data obtained for the mouse model of mastitis, phage therapy could be considered as an innovative alternative to antibiotics for the treatment of bovine mastitis.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Lower respiratory tract infection due to 〈em〉Pseudomonas aeruginosa〈/em〉 has become increasingly challenging, resulting in a worse morbidity and mortality. Airway remodeling is a common phenomenon in this process, to which epithelial-mesenchymal transition (EMT) may contribute as an important promoter. Previous studies showed that epithelium-specific integrin αvβ6–mediated EMT was involved in pulmonary fibrosis via transforming growth factor-β1 (TGF-β1) signaling, but whether integrin αvβ6 plays a role in the 〈em〉P. aeruginosa〈/em〉–associated airway remodeling remains unknown. BEAS-2B cells were incubated with lipopolysaccharide (LPS) from 〈em〉P. aeruginosa〈/em〉 in the presence or the absence of integrin αvβ6–blocking antibodies. Morphologic changes were observed by an inverted microscopy. The EMT markers were detected using Western blotting and immunofluorescence. The activation of TGF-β1-Smad2/3 signaling pathway was assessed. Furthermore, matrix metalloproteinase (MMP)-2 and -9 in the medium were measured using ELISA. 〈em〉P. aeruginosa〈/em〉’s LPS decreased the expression of the epithelial marker E-cadherin and promoted the mesenchymal markers, vimentin and α-smooth muscle actin in BEAS-2B cells. The expression of integrin αvβ6 was significantly increased during EMT process. Blocking integrin αvβ6 could attenuate 〈em〉P. aeruginosa〈/em〉’s LPS-induced EMT markers’ expression via TGF-β1-Smad2/3 signaling pathway. Furthermore, blocking integrin αvβ6 could prevent morphologic changes and oversecretion of MMP-2 and -9. Integrin αvβ6 mediates epithelial-mesenchymal transition in human bronchial epithelial cells induced by lipopolysaccharides of 〈em〉P. aeruginosa〈/em〉 via TGF-β1-Smad2/3 signaling pathway and might be a promising therapeutic target for 〈em〉P. aeruginosa〈/em〉–associated airway remodeling.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Groundwater is regarded as one of the most reliable and vulnerable sources of drinking water in many countries. Declining groundwater levels, due to over-exploitation and climate-change impacts, emphasize the need for sustainable management of this valuable resource. The concept of reliability-resiliency-vulnerability (RRV) has been adopted in this study to assess the spatial changes in the sustainability of aquifers for different periods to identify the main factors affecting groundwater sustainability in Pakistan. This is important for the country, as the substantial decline of groundwater levels in recent years has affected the water security of the growing economy. The satellite-based gridded Gravity Recovery and Climate Experiment (GRACE) groundwater anomaly data for the period 2002–2016 were used for this spatial assessment. The results revealed precipitation as the dominant factor associated with changing groundwater storage in Pakistan. A large decrease in aquifer storage was found over the study period. The groundwater-level decline was found to be greater in the region where agriculture is more intense, resulting in over-exploitation of groundwater for irrigation. The reduction of groundwater storage has led to a decrease in sustainability, especially in recent years (2008–2016) compared with previous periods (2002–2010 and 2005–2013). This study emphasized the need for groundwater resource management strategies such as reduction of groundwater abstraction in drought years, rescheduling the crop calendar to take advantage of rainfall, switching to less water-intensive crops, etc., particularly in groundwater depleting regions.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The dramatic loss of glacial mass in low latitudes is causing shifts in downstream water availability and use during the driest months of the year. The world’s largest concentration of tropical glaciers lies in the Cordillera Blanca range of Peru, where glacial runoff is declining and regional stresses are emerging over water resources. Throughout the Cordillera Blanca, groundwater inputs from alpine meadow–talus complexes, locally known as pampas, supply proglacial streams with up to 80% of their flow during the region’s dry season. Structural knowledge of the pampa aquifers is needed to estimate their drainable groundwater storage capacity and residence time, to elucidate the role and importance of alpine groundwater storage in the regional water budget of the Cordillera Blanca. To understand the structure of these proglacial aquifers, multiple near-surface geophysical methods were implemented in a proglacial valley near dense networks of spring-fed tributaries. Geophysical results and borehole logs suggest groundwater is stored in a confined aquifer composed of buried talus deposits overlain by lacustrine clay, while deeper portions of the unit, 10–15 m in depth, are relatively clay-free and more hydraulically conductive. Based on these findings and assumptions of aquifer porosity, the pampas of the Callejon de Huaylas may store from 0.006 to 0.02 km〈sup〉3〈/sup〉 of groundwater. Furthermore, these findings suggest that the talus aquifers of the Cordillera Blanca were formed in proglacial lakes, followed by infilling with fine lacustrine sediments that confine lower units and allow for groundwater discharge to springs via macropores and preferential flow.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Creating a geological framework for hydrogeological investigations in ice-marginal settings is challenging, as the dynamic nature of ice margins results in heterogeneous sediments and complex geometries that are difficult to characterize geologically and hydraulically. In this study, a multi-scale and multi-tool approach was used to develop a robust and hydraulically calibrated conceptual model of a site in Wisconsin (USA), which constrains the subsurface geologic and hydraulic heterogeneity onsite and can be utilized offsite and in similar settings. Facies analysis, including detailed logging of sediment cores integrated with geophysical surveys, was used to reconstruct the glacial history of the site and to identify key sedimentation styles. Depth-discrete multilevel monitoring wells were used to measure hydraulic head and to explore the relationship between hydraulic conditions and stratigraphy. Results indicate that hydraulic and geological heterogeneity do not necessarily coincide, as hydraulic head profiles of the heterogeneous sediments showed little head change with depth. The minimal observed hydraulic heterogeneity in this complex geologic system is likely due to relatively small and spatially limited differences in hydraulic conductivities, limited water-table relief, and minimal natural or induced transience to enhance local head differentials. Hydraulic data were also used to provide new insights on the style and scale of geologic heterogeneity known to influence permeability within ice-marginal sediments; this is especially relevant at the study site where fine-scale bedding (millimeters to tens of centimeters scale) and lateral continuity of units (meters to hundreds of meters scale) influence water recharge and dense nonaqueous phase liquids migration and distribution.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Mississippi Delta, a portion of the Mississippi Alluvial Plain (MAP) located in northwest Mississippi (USA), is an area dense with industrial-level agriculture sustained by groundwater-dependent irrigation supplied by the Mississippi River Valley alluvial aquifer. Observed declines in groundwater-level elevations and streamflow, contemporaneous with increases in irrigation, have raised concerns about future groundwater availability and the effects of groundwater withdrawals on streamflow. To quantify the impacts of groundwater withdrawals on streamflow and increase understanding of groundwater and surface-water interaction in the MAP, hydrograph-separation techniques were used to estimate baseflow and identify statistical streamflow trends. The analysis was conducted using the US Geological Survey Groundwater Toolbox open-source software and daily hydrologic data provided by a spatially distributed network of paired groundwater wells and streamgage sites. This study found that statistically significant reductions in stream baseflow occurred in areas with substantial groundwater-level declines. The use of hydrograph-separation and trend analyses to quantify the impacts of groundwater withdrawals and the use of streamflow as a proxy for changes in groundwater availability may be applicable in other altered environments. Characterizing and defining hydrologic relations between groundwater and surface water will help scientists and water-resource managers refine a regional groundwater-flow model that includes the Mississippi Delta, which will be used to aid water-resource managers in future decisions concerning the alluvial aquifer.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Groundwater recharge source and flowpaths, along with aquifer medium characteristics, are identified based on nitrate distribution and dynamics. These are significant factors in long-term water-resources management of the Sichuan-Yunnan-Guizhou lead-zinc mining deposits, southwestern China. The results show that high nitrate concentration correlates with lower temperature and heavy isotope enrichment, indicating groundwater recharge from the eastern karst depression area (situated at higher elevation), which has intensive agriculture. Higher NO〈sub〉3〈/sub〉〈sup〉-〈/sup〉 concentration corresponds to higher Ca/Mg ratio in the Carboniferous karst aquifer, both indicating the preferential groundwater flowpath, while the lateral nitrate distribution signifies hydraulic connection with the northern Devonian aquifer passing through the aquitard via NE–SW and N–S trending faults. Nitrate pollution has reached deep sections of the karst aquifers and generated a wide vertical distribution, with the lowest elevation of significant nitrate concentration at –28 m relative to sea level, far lower than the recharge area by over 1,500 m. The variations in groundwater temperature, electrical conductivity and partial pressure of CO〈sub〉2〈/sub〉 in the early rainy season are associated with enhanced dissolution capacity of the carbonate minerals, controlled by the soil CO〈sub〉2〈/sub〉 effect, hence characterizing the mining area as a fissure-dominant karst groundwater system. Under such conditions, nitrate concentration rises and recedes subsequent to recharge events, and these processes characterize nitrate leaching. Overall, the current nitrate distribution is the result of increased agricultural productivity, intensive mine dewatering works and intrinsic media heterogeneity. Nitrate functions as an artificial, stable and cost-effective tracer for groundwater-system characterization in this mining area.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Though springs are the primary source of water for communities in the mid-hills of Nepal, an in-depth scientific understanding of spring systems is missing, preventing the design of effective climate-resilient interventions for long-term sustainability of springs. This study marks the first attempt to combine environmental isotopes analysis with hydrometric and hydrogeological measurements to identify dominant recharge zones for springs in two mountainous catchments—Banlek and Shikarpur—in Far-Western Nepal. In total, 422 water samples collected from rainfall, springs and streams between March 2016 and March 2017 were analyzed for their isotopic composition (δ〈sup〉18〈/sup〉O and δD). Isotopic composition of rainwater shows seasonality, suggesting that different sources of water vapor cause rains in monsoon and in dry season. Rainfall responses of individual springs were used to identify connections to unconfined and deeper groundwater strata. The isotopic composition of springs in the two catchments ranges from −9.55 to −8.06‰ for δ〈sup〉18〈/sup〉O and −67.58 to −53.51‰ for δD. The isotopic signature of the spring sources falls close to the local meteoric water line for the corresponding season, indicating strong rainfall contribution to springs. Altitudinal isotopic gradients suggest mean recharge elevation of 2,600–2,700 m asl for springs in Shikarpur, which lies beyond the surface-water catchment, and a recharge elevation of 1,000–1,100 m asl for Banlek, which partially extends beyond the surface-water catchment. The demarcated recharge zones will be used by government agencies to implement recharge interventions to increase the resiliency and reliability of springs in Far-Western Nepal.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The main goal of this study was to optimize an adaptive neuro-fuzzy inference system (ANFIS) using three meta-heuristic optimization algorithms—genetic algorithm (GA), biogeography-based optimization (BBO) and simulated annealing (SA)—to prepare groundwater potential maps. The methodology was applied to the Booshehr plain, Iran. The results of optimized models were compared with ANFIS individually and three bivariate models: frequency ratio (FR), evidential belief function (EBF), and the entropy model. First, 339 wells with groundwater yield higher than 11 m〈sup〉3〈/sup〉/h were selected and randomly divided into two groups. In all, 238 wells (70%) were used for training the models and 101 wells (30%) were used for testing and validating the models. Fifteen conditioning factors were selected as input parameters for the modeling. The accuracy of the groundwater potential maps for the study area was determined using root mean squared error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE), and standard deviation of error (SD), as well as the area under the receiver operating characteristic (ROC) curve (AUC). Overall, the results demonstrated that ANFIS-GA had the highest prediction capability (AUC = 0.915) for groundwater potential mapping followed by ANFIS-BBO (0.903), entropy (0.862), FR (0.86), ANFIS-SA (0.83), ANFIS (0.82) and EBF (0.80). According to the entropy model, land-use, soil order and rainfall factors had the highest impact on groundwater potential in the study area. The results of this research show that the ANFIS models combined with meta-heuristic optimization algorithms can be a useful decision-making tool for assessment and management of groundwater resources.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A new semi-analytical solution to study groundwater flow fields associated with pumping or injection wells in confined isotropic aquifers with uniform regional flow is proposed and tested against steady-state and transient-state numerical simulations on MODFLOW-MODPATH. The solution is based on the complex potential theory and can be used for large numbers of arbitrarily positioned wells operated with different rates. The solution can be used to follow the movement of water particles in space (within pores or within the equivalent continuous media) and in time with two tracking modes: forward (from origin to target) and backward (from target to origin). The proposed solution is a useful tool that can be used for establishing groundwater resources management practices like designing groundwater remediation solutions, delineating capture zones, defining safeguard perimeters and mapping groundwater vulnerability. Moreover, the paper gives a comparative numerical study of flow fields near pumping wells, showing that, in terms of their shape and position, delineating capture zones using either steady-state or transient-state simulations would lead to practically similar results for long pumping periods. It is also shown that in such cases, the main differences between steady-state and transient-state simulation are present in the computed water particles’ transport time.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Water and salt migration properties are important in many disciplines, including engineering construction, natural disaster prevention, agricultural irrigation and wastewater disposal. Relevant research into unsaturated loess caters to the development needs of the cities located on it. The objective of this study is to identify the water flow dynamics and consequent salt migration and redistribution (as well as their influence on microstructure alteration of the soil) during long-term seepage in unsaturated loess. In this experimental study, a long-term and one-dimensional seepage simulation test is conducted in a loess column. Probes are buried at different depths along the vertical profile to monitor and record the variations of volume water content and electrical conductivity. After the seepage test, soils at different depths are analyzed with different methods to make further investigation, including use of a pressure-plate apparatus to obtain soil-water characteristic curves, ion chromatography to determine the soluble salt components, and scanning electron microscopy to observe the microstructure changes. Good consistency between the different tests is obtained. Based on those results, the water and salt migration patterns and their influence on loess are analyzed and concluded.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The last 60 years has seen unprecedented groundwater extraction and overdraft as well as development of new technologies for water treatment that together drive the advance in intentional groundwater replenishment known as managed aquifer recharge (MAR). This paper is the first known attempt to quantify the volume of MAR at global scale, and to illustrate the advancement of all the major types of MAR and relate these to research and regulatory advancements. Faced with changing climate and rising intensity of climate extremes, MAR is an increasingly important water management strategy, alongside demand management, to maintain, enhance and secure stressed groundwater systems and to protect and improve water quality. During this time, scientific research—on hydraulic design of facilities, tracer studies, managing clogging, recovery efficiency and water quality changes in aquifers—has underpinned practical improvements in MAR and has had broader benefits in hydrogeology. Recharge wells have greatly accelerated recharge, particularly in urban areas and for mine water management. In recent years, research into governance, operating practices, reliability, economics, risk assessment and public acceptance of MAR has been undertaken. Since the 1960s, implementation of MAR has accelerated at a rate of 5%/year, but is not keeping pace with increasing groundwater extraction. Currently, MAR has reached an estimated 10 km〈sup〉3〈/sup〉/year, ~2.4% of groundwater extraction in countries reporting MAR (or ~1.0% of global groundwater extraction). MAR is likely to exceed 10% of global extraction, based on experience where MAR is more advanced, to sustain quantity, reliability and quality of water supplies.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉An integrated hydrogeological modelling approach applicable to hard-rock aquifers in semi-arid data-scarce Africa was developed using remote sensing, rainfall-runoff modelling, and a three-dimensional (3D) dynamic model. The integrated modelling approach was applied to the Hout catchment, Limpopo Province, South Africa, an important agricultural region where groundwater abstraction for irrigation doubled during 1968–1986. Since the 1960s, groundwater levels in irrigated areas have displayed extended periods of decline with partial or full recovery in response to major decadal rainfall events or periods. The integrated dynamic 3D hydrogeological flow model, based on the One-Water Hydrologic Flow Model (MODFLOW-OWHM), helped to understand recharge and flow processes and inform water use and management. Irrigation abstraction was estimated based on irrigated crop area delineated using the Landsat Normalized Difference Vegetation Index (NDVI) and crop water requirements. Using groundwater level data, the model was calibrated (2008–2012) and validated (2013–2015). Estimated mean diffuse recharge (3.3 ± 2.5% of annual rainfall) compared well with estimates from the Precipitation Runoff Modelling System model. Recharge and groundwater storage showed significant inter-annual variability. The ephemeral river was found to be losing, with mean net flux to the aquifer (focused recharge) of ~1.1% of annual rainfall. The results indicate a delicate human-natural system reliant on the small but highly variable recharge, propagating through variable pumping to an even more variable storage, making the combined system vulnerable to climate and anthropogenic changes. The integrated modelling is fundamental for understanding spatio-temporal variability in key parameters required for managing the groundwater resource sustainably.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Distributed numerical models, considered as optimal tools for groundwater resources management, have always been constrained by availability of spatio-temporal input data. This problem is particularly distinct in arid and semi-arid developing countries, characterized by large spatio-temporal variability of water fluxes but scarce ground-based monitoring networks. That problem can be mitigated by remote sensing (RS) methods, which nowadays are applicable for modelling not only surface-water but also groundwater resources, through rapidly increasing applications of integrated hydrological models (IHMs). This study shows implementation of various RS products in the IHM of the Central Kalahari Basin (~200 Mm〈sup〉2〈/sup〉) multi-layered aquifer system, characterized by semi-arid climate and thick unsaturated zone, both enhancing evapotranspiration. The MODFLOW-NWT model with UZF1 package, accounting for variably saturated flow, was set up and calibrated in transient conditions throughout 13.5 years using borehole hydraulic heads as state variables and RS-based daily rainfall and potential evapotranspiration as driving forces. Other RS input data included: digital-elevation-model, land-use/land-cover and soils datasets. The model characterized spatio-temporal water flux dynamics, providing 13-year (2002–2014) daily and annual water balances, thereby evaluating groundwater-resource dynamics and replenishment. The balances showed the dominant role of evapotranspiration in restricting gross recharge to only a few mm yr〈sup〉−1〈/sup〉 and typically negative net recharge (median, −1.5 mm yr〈sup〉−1〈/sup〉), varying from −3.6 (2013) to +3.0 (2006) mm yr〈sup〉−1〈/sup〉 (rainfall of 287 and 664 mm yr〈sup〉−1〈/sup〉 respectively) and implying systematic water-table decline. The rainfall, surface morphology, unsaturated zone thickness and vegetation type/density were primary determinants of the spatio-temporal net recharge distribution.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The unsaturated zone of karst aquifers influences the dynamics and the chemistry of water. Because of a lack of direct access, other than via caves, flows in the aquifer matrix and the smallest conduits remain poorly characterized. The few artificial underground structures in the unsaturated karst provide a rare opportunity to study the variety of flow processes. At the low noise underground research laboratory (Laboratoire Souterrain à Bas Bruit, LSBB) in Rustrel (France), 12 variables (temperature, pH, electrical conductivity, alkalinity, major anions and cations, total organic carbon) have been monitored on 12 perennial or temporary flows and leakages over a 10-year period covering contrasting climatic periods. This unique dataset of 1,135 samples has been used to discriminate, identify, and rank the processes associated with the hydrochemical variability of these different types of flows. A principal component analysis and a hierarchical cluster analysis, using mean values and standard deviation of the flow along the principal components, were performed. The results indicate that seasonal variability, mean water residence time, and the depth of acquisition of the chemical characteristics are the main factors of the variability of chemistry at the monitored flow points. Distinguished clusters highlight the great diversity of flows and processes occurring in the fine pathways that may be neighboring the large and structured fractures and conduits. Long-term monitoring with various climatic conditions appears to be a useful tool for assessing this diversity.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Shenzhen is the major financial and high-tech center in southern China. The megacity has grown rapidly in the last 40 years with the population increasing from about 30,000 in 1979 to 20 million in 2016. The study area (2,015 km〈sup〉2〈/sup〉) is about 42% urban and 58% undeveloped land. The rapid development of the megacity has resulted in severe degradation of the groundwater and surface-water resources and has created a nearly insatiable demand for water, with an average consumption of 2000 × 10〈sup〉6〈/sup〉 m〈sup〉3〈/sup〉/year. Groundwater is an important component of the baseflow of the many streams in the area and is used for potable water supply and irrigation in some of the rural parts of the municipality. This study develops a conceptual model and quantitative framework for assessing the groundwater resources of Shenzhen. The groundwater system consists of shallow aquifers of alluvium and weathered bedrock overlying low permeability igneous and sedimentary rocks. The complex geologic setting was conceptualized as a block structure with blocks bounded by high-angle faults. The water budget in Shenzhen was quantified. The estimated average groundwater discharge is about 12% of annual precipitation. The study provides a starting point to investigate how a megacity such as Shenzhen should manage and protect its groundwater as a strategic resource and environmental asset. It is also a basic management tool for analyzing and contributing to urban drainage concepts such as the “sponge city”.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Extensive dissolution of evaporites has occurred in the Williston Basin, Canada, but it is unclear what effect this has had on bulk permeability. The bulk of this dissolution has occurred from the Prairie Evaporite Formation, which is predominantly halite and potash. However, minor evaporite beds and porosity infilling have also been removed from the overlying Dawson Bay and Souris River formations, which are predominantly carbonates. This study examines whether permeability values in the Dawson Bay and Souris River formations have been affected by dissolution, by analyzing 142 drillstem tests from those formations. For both the Dawson Bay and Souris River formations, the highest permeabilities were found in areas where halite dissolution had occurred. However, the mean permeabilities were not statistically different in areas of halite dissolution compared to those containing connate water. Subsequent precipitation of anhydrite is known to have clogged pore spaces and fractures in some instances. Geochemical relationships found here support this idea but there is no statistically significant relationship between anhydrite saturation and permeability. Geomechanical effects, notably closure of fractures due to collapse, could be a mitigating factor. The results indicate that coupling dissolution and precipitation to changes in permeability in regional flow models remains a significant challenge.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Little attention has been paid to non-Darcy fluid flow through rough-walled rock joints under high hydraulic gradient. Water fluid flow through splitting granite joints was tested beyond the range of previously tested conditions by using an experimental apparatus designed for this study. This apparatus facilitated the quantification of the effects of joint surface roughness and aperture on fluid flow properties. Experimental results showed that Forchheimer’s law could provide an excellent description of the nonlinear relationship between hydraulic gradient and flow velocity, and the variations of Forchheimer coefficients with joint surface roughness and aperture were further explored. In this work, the Reynolds numbers varied between 2,881 and 290,338, and greatly exceeded the critical value of 2,300. Moreover, the fluid flow entered the turbulent flow regime. In accordance with the discriminant factor 〈em〉α〈/em〉 = 0.9 on the basis of Forchheimer’s law, the fluid flow regimes were further divided into two categories: weak turbulence and fully developed turbulence. The corresponding critical Reynolds numbers were obtained and ranged from 17,169 to 94,385. Finally, a new seepage calculation formula for fluid flow through open rough-walled rock joints was established and verified by experimental observations and other formulae. Through a comprehensive consideration of the joint surface roughness and the uneven aperture distribution, the proposed formula could reflect the real fluid flow situation. The findings may prove beneficial for improving understanding of the nonlinear fluid flow in jointed rocks.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Novel findings about the general properties of an aquifer were obtained by applying the pumping approach introduced by Summa (2010). The approach of keeping the pump’s rotation speed constant was chosen over the well-known and widely used constant discharge method. The present analysis was performed on a set of unpublished data acquired during the same field test that was described in Summa (2010). The values of the instantaneous discharge and instantaneous drawdown were obtained. The contribution of the water already stored in the well to the overall capacitance of the aquifer was cancelled out for the field data that were processed. It was then possible to obtain a discharge-time function depending only upon the aquifer discharge. The discharge-time curve that was obtained showed a behaviour practically indistinguishable from the discharge-time curve for a resistor-inductor-capacitor (RLC) circuit with a direct current. By fully exploiting that circuit analogy, it was possible to evaluate the resistance, capacitance and inductance (inertia) of the aquifer. These parameters were estimated from the RLC solution that best fit the discharge-time curve. The value of the hydraulic resistance that was obtained was of the same order of magnitude as the inverse value of the transmissivity, already calculated for the same aquifer in previous work. This matching suggests that this model, as a future development of the present study, can be tested against the standard models regarding the determination of the traditional hydrogeological parameters. Summa G (2010) A new approach to the step-drawdown test, Water SA, 36(3):279–286.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉VDFST-CFP (variable-density flow and solute transport–conduit flow process) is a density-dependent discrete-continuum numerical model for simulating seawater intrusion in a dual-permeability coastal karst aquifer. A previous study (Xu and Hu 2017) simulates variable-density flow only in a single conduit, and studies the parameter sensitivities only in the horizontal case (2D domain as horizontal section) by the VDFST-CFP model. This paper focuses on the density-dependent vertical case (2D domain as vertical section) with two major improvements: 1) when implementing double-conduit networks in the domain, simulated intruded plumes in the porous medium are extended in the double-conduit scenario, compared to the single-conduit system; 2) by quantifying micro-textures on the conduit wall by the Goudar-Sonnad equation and considering macro-structures as local head loss. Sensitivity analysis shows that medium hydraulic conductivity, conduit diameter and effective porosity are important parameters for simulating seawater intrusion in the discrete-continuum system. On the other hand, rougher micro-structures and additional macro-structure components on the conduit wall would reduce the distance of seawater intrusion to the conduit system, but, rarely affect salinity distribution in the matrix. Compared to the equivalent mean roughness height, the new method (with more detailed description of structure) simulates seawater intrusion slightly landward in the conduit system. The macro-structure measured by local head loss is more reasonable but needs further study on conduit flow. Xu and Hu (2017) Development of a discrete-continuum VDFST-CFP numerical model for simulating seawater intrusion to a coastal karst aquifer with a conduit system. Water Resources Research: 53, 688-711.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Excessive use of antibiotics contributes to the selection of resistant bacteria and intestinal colonization with multiresistant pathogens poses a risk factor for subsequent infections. The present study assessed vancomycin-resistant enterococci (VRE) carriage rates in patients admitted to our tertiary care hospital. Stool samples sent for routine culturing were screened with vancomycin containing solid or broth enrichment media. VRE isolates were identified with matrix-assisted laser desorption/ionization-time of flight mass spectrometry and antibiotic susceptibilities were tested by E-test. Vancomycin resistance genes were detected by polymerase chain reaction. Medical records of carriers were examined for suspected risk factors for colonization. Altogether 3025 stool specimens were analyzed. Solid media identified a VRE carriage rate of 2.2% while broth enrichment detected 5.8%. Seventy percent of the isolates were 〈em〉Enterococcus faecium. VanB〈/em〉 genotype was detected in 38.2%, 〈em〉VanA〈/em〉 in 37.3%, 〈em〉VanC1〈/em〉 in 22.6%, and 〈em〉VanC2〈/em〉 in 1.9%. All VRE were sensitive to linezolid, daptomycin, and tigecycline. Collective risk factors for carriage were diabetes, normal flora absence, 〈em〉Clostridioides difficile〈/em〉 positivity, longer hospital stay, and advanced age. 78.5% of the carriers received antibiotic therapy which was metronidazole in most cases (47.3%)〈em〉.〈/em〉 We recommend regular screening of risk groups such as patients with diabetes, history of recent hospitalization, or former 〈em〉C. difficile〈/em〉 infection as an imperative step for preventing VRE dissemination.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The objectives of this study were (i) to isolate and characterize of cultivable denitrifying bacteria using classic microbiological and molecular methods, (ii) to compare of 16S rRNA and 〈em〉nosZ〈/em〉 genes as molecular markers, (iii) to determine bacterial community structure and diversity in soil samples using single-strand conformation polymorphism (SSCP) analysis. In this study, 49 bacterial isolates were cultivated and phylogenetic analyses grouped them into two phyla: 〈em〉Proteobacteria〈/em〉 (37 species) and 〈em〉Firmicutes〈/em〉 (12 species). Our study showed that the 〈em〉nosZ〈/em〉 functional gen could be used to identify denitrifying bacteria abundance in environment but could not be used to identify pure bacterial cultures. In addition, the bacterial community structure showed significant differences among the various soil types. Phylogenetic analysis of community structure indicated that 51 clones could be divided into 2 phylotypes. Uncultured bacteria (80.4%) and 〈em〉Gammaproteobacteria〈/em〉 (19.6%) were the dominant components of the soil bacterial community. For 16S rRNA, PCR products of 49 bacteria were obtained with 27F-1492R primer pairs. For 〈em〉nosZ〈/em〉, PCR products were obtained with primers 1F-1R (259 bp), 2F-2R (267 bp), and F-1622R (453 bp) of 39 bacteria that the single 〈em〉nosZ〈/em〉 band provided on the agarose gel. The bacterial 16S rRNA gene clone library was dominated by 〈em〉Gammaproteobacteria〈/em〉 and 〈em〉Bacilli〈/em〉. The 〈em〉nosZ〈/em〉 clone sequences did not represent the bacteria from which they were obtained but were found to be closer to the environmental clones. Our study showed that the 〈em〉nosZ〈/em〉 functional gene could be used to identify denitrification abundance in environment but could not be used to identify pure bacterial cultures. It was also found that the 〈em〉nosZ〈/em〉 sequences showed uncultured denitrifier species.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Vancomycin is often used in orthopedic surgery as a local prophylaxis of bacterial infection. The aim of this work was to compare the release of vancomycin and its biologically inactive crystalline degradation products (CDP-1) during in vitro experiments from different types of local antibiotic delivery systems (bone grafts and bone cements). The concentrations of vancomycin and its crystalline degradation products were determined by high-performance liquid chromatography. Each experiment was performed in a phosphate buffer solution over 21 days. Morselized bone grafts, synthetic bone cements Palacos and Copal, and synthetic bone grafts were tested as local carriers of vancomycin. The highest concentration approximately 670 mg/L of vancomycin was released from synthetic bone grafts Actifuse. Even after 21 days, the concentration of vancomycin was still above the minimum inhibitory concentration (MIC). The maximum concentration of vancomycin released in two experiments with human bone grafts exceeded 600 mg/L during the first day and was still above MIC level 21 days later when the experiment was concluded. By comparing the synthetic bone cements Palacos and Copal, Copal had the average maximum concentration of only 32.4 mg/L and Palacos 35.7 mg/L. The concentration of vancomycin fell below the MIC for vancomycin-resistant 〈em〉Staphylococcus aureus〈/em〉 (VRSA) on the seventh day with Palacos and the ninth day with Copal. This study showed the insufficient concentration of released vancomycin from synthetic bone cements at the end of the experiment. For improvement of local prophylaxis, it would be beneficial to increase the amount of vancomycin in bone cements.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The present study was designed to characterize six 〈em〉Trueperella〈/em〉 (〈em〉T.〈/em〉) 〈em〉abortisuis〈/em〉 strains, cultured over a period of 5 months from fetus and abortion material of six pigs of a single farm in Mecklenburg-West Pomerania federal state, Germany. It was of interest to investigate the epidemiological relationships of the six strains among each other and whether a single bacterial clone was responsible for the abortion situation of the single farm. All six strains were identified phenotypically, by MALDI-TOF MS analysis and by phylogenetic analysis based on 16S rRNA gene and 〈em〉gap〈/em〉 (encoding the glyceraldehyde 3-phosphate dehydrogenase) and 〈em〉tuf〈/em〉 (encoding elongation factor tu) gene sequencing. Further genotypic comparison was performed using different genomic DNA fingerprint methods including BOX-PCR, (GTG)〈sub〉5〈/sub〉-PCR, and three RAPD-PCRs. The sequence analysis of the genes 〈em〉gap〈/em〉 and 〈em〉tuf〈/em〉 and the genomic DNA fingerprinting results revealed, as noval findings, that the six 〈em〉T. abortisuis〈/em〉 strains cultured from a single farm represent six different bacterial clones showing a genetic variability of this bacterial species in the pig population. All six 〈em〉T. abortisuis〈/em〉 strains were isolated in mixed culture with several other bacterial species. However, the 〈em〉T. abortisuis〈/em〉 strain, generally found in high numbers, seemed to be responsible for the abortion situation in the farm.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Getting into a weakened organism, non-tuberculosis mycobacteria (NTMB) contact not only with the cells of the microorganism but also with the microflora of the human body; however, these interactions are poorly understood. The purpose of this work was to study the effect of NTMB supernatants on the properties of conditionally pathogenic microorganisms in their interaction with red blood cells. We used strains of non-tuberculous mycobacteria 〈em〉Mycobacterium iranicum〈/em〉 and 〈em〉M. rutilum〈/em〉, as well as strains of 〈em〉Staphylococcus epidermidis〈/em〉 and 〈em〉Escherichia coli〈/em〉. Using the fluorescence in situ hybridisation (FISH) method, the processes of adhesion to the surface of erythrocytes and the intra-erythrocyte penetration of cells of 〈em〉S. epidermidis〈/em〉 and 〈em〉E. coli〈/em〉 under the influence of NTMB supernatants were studied. To study changes in the haemoglobin molecule under the action of the supernatants of NTMB, spectral analysis was performed. Statistical processing was performed using STATISTIKA 6.0. The results showed that the supernatants of 〈em〉M. iranicum〈/em〉 and 〈em〉M. rutilum〈/em〉 increased the adhesion of conditionally pathogenic bacteria with a low level of AntiHbA to the surface of erythrocytes by 3–4 times. It also increased the intra-erythrocyte penetration of cells of 〈em〉S. epidermidis〈/em〉 and 〈em〉E. coli〈/em〉 relative to the control values. As a result of studying the haemoglobin spectrum of erythrocytes under the influence of 〈em〉M. iranicum〈/em〉, a decrease in the optical density values of oxyhaemoglobin by a factor of 2 relative to the values in the control sample was noted. Thus, the supernatants of NTMB have a multidirectional effect on the interaction of opportunistic microorganisms with erythrocytes, increasing the adhesive activity and the penetration of cells into the erythrocytes, as well as reducing the optical density of oxyhaemoglobin.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The aim of the present study was to develop an ion-selective electrode method for the continuous determination of the intracellular pH in 〈em〉Lactobacillus plantarum〈/em〉 using a small-scale bioreactor. This method employed a salicylate-selective electrode basing on the distribution of salicylic acid across the cytoplasmic membrane. This developed electrode responded to salicylate concentrations above 20 μmol/L with a Nernstian sensitivity. The energized and concentrated cells were added into a thermostated small-scale bioreactor that contained the salicylate anions dissolved in a 100 mmol/L potassium phosphate buffer at different pH values. The changes in salicylate concentration that occurred in the medium containing bacterial suspension were measured as a voltage change. The cells of 〈em〉Lactobacillus plantarum〈/em〉 showed maintenance of pH homeostasis at the studied pH ranging from 4.0 to 7.0, and they kept a neutral intracellular pH up to 5.8. The simplicity of the measuring preparation and the relatively low cellular concentration, as well as the advantages of the small-scale bioreactor, lead us to believe that the described method can facilitate the study of the physicochemical factors on the intracellular pH of lactic acid bacteria using a single pH probe in one method.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Microbial contamination poses a great threat to aviation system security through mechanisms such as microbiologically influenced corrosion (MIC), fuel filter clogging, and fuel deterioration. In this study, a survey of microbial contamination in aviation fuel obtained from aircraft fuel tanks was performed to test the relationship between microbial contamination and aircraft service life. The contaminating microorganisms were counted, isolated, identified, and subjected to preliminary characterization. A low risk of microbial contamination in the selected samples was confirmed, and there was no significant difference in the counts between culturable bacteria and fungi (〈em〉p〈/em〉 〉 0.05). Phylogenetic analysis tree indicated that the diversity of culturable microorganisms was rather low, with 17 bacterial isolates belonging to 13 genera and 12 fungal isolates belonging to 5 genera. No yeast was isolated. The growth characteristics of these isolates indicated that the aircraft fuel tanks harbored various microorganisms that were able to utilize the aviation fuel as a source of carbon and energy. Meanwhile, some isolates caused emulsification and produced acid. The conclusions of this study were that various hazardous microorganisms can root in aircraft aviation fuel tanks. There was no relationship between microbial contamination and aircraft service life (〈em〉p〈/em〉 〉 0.05), and continuous good maintenance suppressed microbial proliferation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The antifouling, antimicrobial, elution behavior, skin irritant, and cytotoxicity properties of water-soluble phosphate glass on stainless steel were evaluated. Water-soluble phosphate glass samples with 35% Cu (mol/mol) were prepared by altering the network modifier (Na〈sub〉2〈/sub〉O, K〈sub〉2〈/sub〉O) and network former (P〈sub〉2〈/sub〉O〈sub〉5〈/sub〉, B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉) compositions. The materials were melted at temperatures within the range of 850–950 °C. The melt was then quenched and ground into fine particles using a twin roll mill. The resulting water-soluble glasses were prepared as glass frit (size 〈 100 μm) using a sieve. The amorphous phase was determined by X-ray diffraction and differential thermal analysis. Water-soluble glasses with a reduced Cu ion elution rate of 1.2 ppm per week were formed because the chemical resistances of the formulated glasses improved as the P〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 content decreased and the B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 content increased. To test its antifouling properties, the glass frit was mixed with paint and coated onto a STS316L sheet. The surface roughness was increased markedly from 1.4 to 19.2 nm, increasing the specific surface area for antimicrobial activity. It was demonstrated that the proposed method was able to form noncytotoxic, nonirritant, water-soluble glasses with 99.9% antimicrobial activity against 〈em〉Staphylococcus aureus.〈/em〉 These results suggest that water-soluble phosphate glass on STS316L sheets could be useful in filtration plants.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Nosocomial infections are an important cause of morbi-mortality worldwide. The increase in the rate of resistance to conventional drugs in these microorganisms has stimulated the search for new therapeutic options. The nitro moiety (NO〈sub〉2〈/sub〉) is an important pharmacophore of molecules with high anti-infective activity. We aimed to synthesize new nitro-derivates and to evaluate their antibacterial and anti-〈em〉Candida〈/em〉 potential in vitro〈em〉.〈/em〉 Five compounds [3-nitro-2-phenylchroman-4-ol (〈strong〉3〈/strong〉); 3-nitro-2-phenyl-2H-chromene (〈strong〉4a〈/strong〉); 3-nitro-2-(4-chlorophenyl)-2H-chromene (〈strong〉4b〈/strong〉); 3-nitro-2-(4-fluorophenyl)-2H-chromene (〈strong〉4c〈/strong〉), and 3-Nitro-2-(2,3-dichlorophenyl)-2H-chromene (〈strong〉4d〈/strong〉)] were efficiently synthesized by Michael-aldol reaction of 2-hydroxybenzaldehyde with nitrostyrene, resulting in one β-nitro-alcohol (〈strong〉3〈/strong〉) and four nitro-olefins (〈strong〉4a〈/strong〉–〈strong〉4d〈/strong〉). The antibacterial and anti-〈em〉Candida〈/em〉 potentials were evaluated by assaying minimal inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and minimum bactericidal concentration (MBC). Mono-halogenated nitro-compounds (〈strong〉4b〈/strong〉 and 〈strong〉4c〈/strong〉) showed anti-staphylococcal activity with MIC values of 15.6–62.5 μg/mL and MBC of 62.5 μg/mL. However, the activity against Gram-negative strains was showed to be considerably lower and our data suggests that this effect was associated with the outer membrane. Furthermore, nitro-compounds 〈strong〉4c〈/strong〉 and 〈strong〉4d〈/strong〉 presented activity against C〈em〉andida〈/em〉 spp. with MIC values ranging from 7.8–31.25 μg/mL and MFC of 15.6–500 μg/mL. In addition, these compounds were able to induce damage in fungal cells increasing the release of intracellular material, which was associated with actions on the cell wall independent of quantitative changes in chitin and β-glucan. Together, these findings show that nitro-compounds can be exploited as anti-staphylococcal and anti-〈em〉Candida〈/em〉 prototypes.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Flap endonuclease is a structure-specific nuclease which cleaves 5′-flap of bifurcated DNA substrates. Genome sequence of 〈em〉Thermococcus kodakarensis〈/em〉 harbors an open reading frame, Tk1281, exhibiting high homology with archaeal flap endonucleases 1. The corresponding gene was cloned and expressed in 〈em〉Escherichia coli〈/em〉, and the gene product was purified to apparent homogeneity. Tk1281 was a monomer of 38 kDa and catalyzed the cleavage of 5′-flap from double-stranded DNA substrate containing single-stranded DNA flap. The highest cleavage activity was observed at 80 °C and pH 7.5. Under optimal conditions, Tk1281 exhibited apparent 〈em〉V〈/em〉〈sub〉max〈/sub〉 and 〈em〉K〈/em〉〈sub〉m〈/sub〉 values of 278 nmol/min/mg and 37 μM, respectively, against a 54-nucleotide double-stranded substrate containing a single-stranded 5′-flap of 27 nucleotides. A unique feature of Tk1281 is its highest activation in the presence of Co〈sup〉2+〈/sup〉 and no activation with Mn〈sup〉2+〈/sup〉. To the best of our knowledge, this is the first cloning and characterization of a flap endonuclease from the genus 〈em〉Thermococcus〈/em〉.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉〈em〉Chromera velia〈/em〉 is a marine photosynthetic relative of human apicomplexan parasites. It has been isolated from coral reefs and is indicted for being involved in symbioses with hermatypic corals. 〈em〉C. velia〈/em〉 has been subject to intensive research, but still very little is known of its response to light quality and quantity. Here, we have studied the growth and compositional responses of 〈em〉C. velia〈/em〉 to culture under monochromatic light (blue, green or red), at two photon flux densities (PFD, 20 and 100 μmol photons m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉). Our results show that 〈em〉C. velia〈/em〉 growth rate is unaffected by the quality of light, whereas it responds to PFD. However, light quality influenced cell size, which was smaller for cells exposed to blue monochromatic light, regardless of PFD. PFD strongly influenced carbon allocation: at 20 μmol photons m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉, carbon was mainly allocated into proteins while at 100 μmol photons m〈sup〉−2〈/sup〉 s〈sup〉−1〈/sup〉, carbon was allocated mainly into carbohydrate and lipid pools. The blue light treatment caused a decrease in the lipids and carbohydrates to proteins and thus suggested to affect nitrogen metabolism in acclimated cells. Whole-cell absorption spectra revealed the existence of red-shifted chlorophyll 〈em〉a〈/em〉 antenna not only under red light but in all low PFD treatments. These findings show the ability of 〈em〉C. velia〈/em〉 to successfully adapt and thrive in spectrally very different environments of coral reefs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The geological basins in Australia across which the hydrogeological Great Artesian Basin (GAB) exists, hold significant coal and coal seam gas (CSG) resources. Resource development from deep sedimentary basins often involves the risk of impacting groundwater resources. Predictive analysis of potential impacts on water resources are important for the risk analysis of resource development projects. A regional-scale numerical groundwater model was developed to probabilistically assess potential groundwater impacts due to additional coal resource development from a deep sedimentary basin underlying the GAB. The probabilistic simulation considered the plausible variability of the model parameters and accounted for uncertainties. Predictive uncertainty analysis was undertaken using a rejection sampling method after screening the model runs using predefined objective functions to evaluate the performance of the model runs with respect to historical observations. The predictive simulations were undertaken using 2,618 model runs to obtain maximum head drawdown caused by CSG and coal mining developments. The results showed that the water-table drawdown from an individual coal mining development becomes insignificant (maximum difference in drawdown 〈0.2 m) beyond 5 km. In general, less water-table drawdown was produced near the CSG development site but small amounts of drawdown spread further from it. Separation of surficial aquifers from deeper coal formations, as generally found in the GAB, limits the propagation of CSG-induced drawdown into the aquifers closer to the surface. While this study was specifically done for the Namoi region, similar outcomes could be expected in the broader GAB and other basins where equivalent hydrogeological conditions exist.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The following series of articles form a special issue organized by the Algatech Center of the Institute of Microbiology CAS dedicated to the memory of Dr. Ivan Šetlík.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The rapid emergence of resistance in pathogenic bacteria together with a steep decline in economic incentives has rendered a new wave in the drug development by the pharmaceutical industry and researchers. Since cyanobacteria are recognized as wide producers of pharmaceutically important compounds, we investigated thirty-four cyanobacterial extracts prepared by solvents of different polarities for their antimicrobial potential. Almost all tested cyanobacterial strains exhibited some degree of antimicrobial bioactivity, with more general effect on fungal strains compared with bacteria. Surprisingly ~50% of cyanobacterial extracts exhibited specific activity against one or few bacterial indicator strains with Gram-positive bacteria being more affected. Extracts of two most promising strains were subjected to activity-guided fractionation and determination of the minimum inhibitory concentration (MIC) against selected bacterial and fungal isolates. Multiple fractions were responsible for their antimicrobial effect with MIC reaching low-micromolar concentrations and in some of them high level of specificity was recorded. Twenty-six bioactive fractions analyzed on LC-HRMS/MS and Global Natural Product Social Molecular Networking (GNPS) online workflow using dereplication resulted in identification of only forty-nine peptide spectrum matches (PSMs) with eleven unique metabolites spectrum matches (MSMs). Interestingly, only three fractions from 〈em〉Nostoc calcicola〈/em〉 Lukešová 3/97 and four fractions from 〈em〉Desmonostoc〈/em〉 sp. Cc2 showed the presence of unique MSMs suggesting the presence of unknown antimicrobial metabolites among majority of bioactive fractions from both the strains. Our results highlight potential for isolation and discovery of potential antimicrobial bioactive lead molecules from cyanobacterial extracts.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Citrus black spot (CBS) and post-bloom fruit drop (PFD), caused by 〈em〉Phyllosticta citricarpa〈/em〉 and 〈em〉Colletotrichum abscissum〈/em〉, respectively, are two important citrus diseases worldwide. CBS depreciates the market value and prevents exportation of citrus fruits to Europe. PFD under favorable climatic conditions can cause the abscission of flowers, thereby reducing citrus production by 80%. An ecofriendly alternative to control plant diseases is the use of endophytic microorganisms, or secondary metabolites produced by them. Strain LGMF1631, close related to 〈em〉Diaporthe〈/em〉 cf. 〈em〉heveae〈/em〉 1, was isolated from the medicinal plant 〈em〉Stryphnodendron adstringens〈/em〉 and showed significant antimicrobial activity〈em〉,〈/em〉 in a previous study. In view of the potential presented by strain LGMF1631, and the absence of chemical data for secondary metabolites produced by 〈em〉D.〈/em〉 cf. 〈em〉heveae〈/em〉, we decided to characterize the compounds produced by strain LGMF1631. Based on ITS, TEF1, and TUB phylogenetic analysis, strain LGMF1631 was confirmed to belong to 〈em〉D.〈/em〉 cf. 〈em〉heveae〈/em〉 1. Chemical assessment of the fungal strain LGMF1631 revealed one new 〈em〉seco〈/em〉-dihydroisocoumarin [cladosporin B (〈strong〉1〈/strong〉)] along with six other related, already known dihydroisocoumarin derivatives and one monoterpene [(−)-(1〈em〉S〈/em〉,2〈em〉R〈/em〉,3〈em〉S〈/em〉,4〈em〉R〈/em〉)-〈em〉p〈/em〉-menthane-1,2,3-triol (〈strong〉8〈/strong〉)]. Among the isolated metabolites, compound 〈strong〉5〈/strong〉 drastically reduced the growth of both phytopathogens in vitro and completely inhibited the development of CBS and PFD in citrus fruits and flowers. In addition, compound 〈strong〉5〈/strong〉 did not show toxicity against human cancer cell lines or citrus leaves, at concentrations higher than used for the inhibition of the phytopathogens, suggesting the potential use of (−)-(3〈em〉R〈/em〉,4〈em〉R〈/em〉)-〈em〉cis〈/em〉-4-hydroxy-5-methylmellein (〈strong〉5〈/strong〉) to control citrus diseases.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The biogenesis of the cyanobacterial photosystem II (PSII) complex requires a number of auxiliary assembly factors that improve efficiency of the process but their precise function is not well understood. To assess a possible synergic action of the Ycf48 and Ycf39 factors acting in early steps of the biogenesis via interaction with the nascent D1 subunit of PSII, we constructed and characterised a double mutant of the cyanobacterium 〈em〉Synechocystis〈/em〉 PCC 6803 lacking both these proteins. In addition, we also deleted the 〈em〉ycf39〈/em〉 gene in the double mutant lacking Ycf48 and Pam68, the latter being a ribosomal factor promoting insertion of chlorophyll (Chl) into the CP47 subunit of PSII. The resulting double ΔYcf48/ΔYcf39 and triple ΔYcf48/ΔPam68/ΔYcf39 mutants were deficient in PSII and total Chl, and in contrast to the source mutants, they lost the capacity for autotrophy. Interestingly, autotrophic growth was restored in both of the new multiple mutants by enhancing Chl biosynthesis using a specific ferrochelatase inhibitor. Taking together with the weak radioactive labelling of the D1 protein, these findings can be explained by inhibition of the D1 synthesis caused by the lack and/or incorrect binding of Chl molecules. The results emphasise the key importance of the sufficient Chl supply for the PSII biogenesis and also support the existence of a so far enigmatic regulatory mechanism leading to the reduced overall Chl biosynthesis/accumulation when the PSII assembly is impaired.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The northern Aquitaine basin (southwest France) is a large multi-layer aquifer system that contains groundwater with strong residence-time variability ranging from years to tens of thousands of years. This system constitutes an archive of paleoclimate variations. A multi-parameter approach involving isotopic tracers (〈sup〉14〈/sup〉C, 〈sup〉18〈/sup〉O, 〈sup〉2〈/sup〉H) was used to determine the residence time of groundwater and to document climate fluctuations, while dissolved noble gases were used to estimate mean annual temperatures (noble gas recharge temperatures, NGRT) at the water table. Near-surface ground temperature reconstruction from 40 ka cal〈span〉 BP〈/span〉 to the present was made using data collected from five aquifers. The coldest temperatures are recorded for late Marine Isotopic Stage (MIS) 3 and MIS 2, i.e. between 36 and 18 ka cal〈span〉 BP〈/span〉. The mean NGRT for the period 27–18 ka cal〈span〉 BP〈/span〉 is estimated at 5.9 ± 0.9 °C, and a strong increase towards modern values (11–13 °C) is observed after 15 ka cal〈span〉 BP〈/span〉. The temperature change between the Holocene and the Last Glacial ranges from 5 to 7 °C, in agreement with previous NGRT studies in Europe. Since mean near-surface ground temperatures during the glacial were well above 0 °C, long-term presence of permafrost in northern Aquitaine is unlikely. However, a possible warm bias in reconstructed temperatures during the coldest events lies in the fact that NGRTs in cold regions do not reflect annual means but rather the ground temperature during the thaw months.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Nitrate is found in groundwater due to natural and anthropic processes. Nitrate content in groundwater is associated with factors such as human activities, soil type, climate, geology and chemistry of groundwater. Some of these factors (climate and geology) coincide with those that determine the type of groundwater flow system (local, intermediate or regional) present in an area which, in turn, is influenced by climate, stratigraphy, and type of subsoil and surface rocks; therefore, it is expected that the concentration of nitrate is related to the type of groundwater flow. The relationship between the concentration of nitrate in groundwater samples and the type of flow was analyzed in an aquifer system located in the Trans-Mexican Volcanic Arc, within the Michoacán-Guanajuato volcanic complex. The system is composed of two hydrogeological units, one volcanic and the other sedimentary, with the presence of geological faults, in a context where there is agricultural activity and deficient domestic wastewater management. To improve understanding of the overall aquifer system, 34 groundwater samples (28 wells, 6 springs) were analyzed. The results indicate that each flow system presents characteristic patterns of nitrate concentration and groundwater chemical composition. A high nitrate concentration was found in local and local-intermediate flow systems. Nitrate concentration decreased from local to intermediate and regional flows. The nitrate concentration decreased depending on groundwater flow direction, so it is possible to use nitrate as a parameter to differentiate groundwater flow systems.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Groundwater plays a vital role in the arid Southern Gobi Region (SGR) of Mongolia. It is the only source of water supply and is largely utilized for mining operations, such as those at Oyu Tolgoi Mine. The area is expected to face severe water shortages for mining and drinking water, which may be related to changes in groundwater recharge due to climate change. Understanding the geochemical evolution of groundwater and recharge mechanisms is thus paramount for water resource management. In this study, for the first time, chemical and isotopic approaches have been used to characterize the groundwater origin and its associated recharge processes in the Gunii Khooloi basin, which is located in the SGR. Shallow groundwater is mainly characterized by Na(HCO〈sub〉3〈/sub〉) and NaCl type; however, Gunii Khooloi aquifer is classified as NaCl type with high electrical conductivity. The stable isotope composition of the water in the deep Cretaceous confined aquifer shows depletion in 〈sup〉2〈/sup〉H and 〈sup〉18〈/sup〉O relative to modern rainfall and the Quaternary shallow aquifer, which indicates a weak interaction between the two aquifers. Modern groundwater was identified in the shallow streambed aquifer, probably due to the direct infiltration of rainfall. On the other hand, 〈sup〉14〈/sup〉C ages in the deep groundwater range from 2,800 to 33,500 years, which suggests that this is paleowater that was recharged during the glacial age. The results indicate that there is a need for strategic groundwater management in the Gunii Khooloi basin.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Cassino plain is a Quaternary intermontane basin of the central-southern Apennines, Italy. The plain has outstanding groundwater resources (total discharge of 23,000 L/s), thanks to the huge karst basins that surround the area. The area has been involved in many hydrogeological interests since the 1970s due to the economic importance and construction of the Western Campania Aqueduct for the water supply of Naples city and its hinterland. Despite its importance, the area lacks a common accepted hydrogeological conceptual model due to the complex geological setting. Two contrasting conceptual models already exist in the literature, with the first model based on a quantitative hydrogeological approach and the second on fieldwork. Through a literature analysis and further detailed field surveys, a new conceptual model is presented, acknowledging the thrust tectonics of the Apennine chain. The model unveils the most important hydrogeological issues of the area, serving as a useful tool for groundwater management, as well as for considering the changing anthropic and climate scenarios. In particular, the study redefines the hydrostructure extents and the groundwater flowpaths, characterizing the main water resources as Gari and Peccia springs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Accurate characterization of aquifers remains challenging for large-scale systems because of the spatial heterogeneity of hydraulic properties and temporal variability of hydrologic inputs. This study highlights the importance of integrating geological, hydrogeological and geophysical approaches to characterize an aquifer and evaluate groundwater productivity. Data from geological maps, drill logs, a pumping test, vertical electrical soundings (VES) and different field hydrogeological studies were combined and applied to a heavily extracted aquifer system—Lake Haramaya watershed, Ethiopia. From the geological characterization, the aquifer was found to be a single heterogeneous and anisotropic unconfined unit. Significant differences were found between the three-dimensional geological models of the aquifer developed from the drill logs and VES data; the VES data were likely affected by moisture content. The pumping-test and VES data were combined to estimate transmissivity (〈em〉T〈/em〉; 126.5 ± 25.8 m〈sup〉2〈/sup〉/day) and hydraulic conductivity (〈em〉K〈/em〉; 4.1 ± 1.0 m/day). This combined use allowed for a reduction in uncertainty (40.1% for 〈em〉T〈/em〉 and 33.3% for 〈em〉K〈/em〉) compared with values estimated from the VES data alone. The combined approach also allowed for much greater spatial coverage and a higher resolution characterization of the aquifer. The available volume of groundwater resource in the system was estimated at ~0.62 ± 0.09 km〈sup〉3〈/sup〉. The groundwater extraction rate was ~30,120 m〈sup〉3〈/sup〉〈em〉/〈/em〉day, approximately double the estimated sustainable yield of the aquifer (15,720 m〈sup〉3〈/sup〉/day). This showed that the current exploitation rate could exhaust groundwater resources in 27–32 years and should be reduced by 50% to ensure sustainability of the groundwater resource.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In the process of solute transport, dispersivity and hydrodynamic dispersion coefficients are important factors that define the distribution and migration of dissolved salts in the aquifer. Tracer tests were carried out in wells located in the northeast coast of Yucatan, Mexico, whereby only the freshwater thickness of the aquifer was analyzed. Sodium chloride (NaCl) was used as a tracer. Groundwater flow velocity was estimated with the Drost dilution point method. To analyse the solute transport, the analytical model for instantaneous injection was chosen, which is derived from the advection–dispersion equation, and the dispersivity and longitudinal dispersion coefficients were determined. The results indicate that the longitudinal dispersivity and hydrodynamic dispersion of the aquifer vary from 2.56 to 2,500 m and between 1 × 10〈sup〉−3〈/sup〉 and 1 × 10〈sup〉−2〈/sup〉 m〈sup〉2〈/sup〉/s, respectively. In the areas of Telchac Puerto, Dzilam Bravo and San Felipe, advection is the most important solute transport mechanism, while El Cuyo has lower velocity ranges than other locations in the study area and salts tend to disperse. Groundwater flow velocity varies between 3.1 × 10〈sup〉−7〈/sup〉 and 8.65 × 10〈sup〉−5〈/sup〉 m/s, associated with the flow in the karstic aquifer matrix, with maximum values ​​of 1.5 × 10〈sup〉−4〈/sup〉 m/s, associated with the karstification of the aquifer. Groundwater flow velocity increases towards the coast, which is consistent with the fact that the aquifer discharges to the sea. It is observed that in the first 10 m of aquifer, the velocities are higher than those determined in deeper layers, up to an order of magnitude.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Hydrogeologic processes and shallow subsurface flows control runoff generation, groundwater dynamics, and permafrost distribution at high latitudes and elevations. Electrical resistivity tomography (ERT) can effectively delineate the frozen and thawed zones in the cold environment and can be applied in permafrost hydrogeology by measuring the differences in subsurface electrical potential. A combined approach of ERT and borehole measurements is implemented to map the flow paths of the supra-permafrost and sub-permafrost waters around the Wanlong Worma Lake (WWL) basin in the headwaters of the Yellow River (northeastern Qinghai-Tibet Plateau, China). The ERT sounding results are further validated using drilling records and measured data on ground temperatures and groundwater level. Then, basic features for permafrost hydrogeology are outlined according to the ERT sounding, vegetation distribution, and geological data in the WWL basin. The results show the presence of permafrost at depths up to 15 m, in which electrical resistivity is 〉250 Ωm. Below the permafrost (at depth 15–80 m), electrical resistivity is generally 〈100 Ωm. At the depth where an aquifer occurs (20–60 m), electrical resistivity is in the range 1–25 Ωm. The sub-permafrost water moves towards the zone of taliks (unfrozen ground) under the hydraulic gradient controlled by local permafrost distribution and is affected by terrain relief. This work demonstrates the capability of ERT for delineating the distribution of the aquifers of the supra- and sub-permafrost waters and for understanding changes in hydraulic connections in a rapidly degrading alpine permafrost basin.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Karahayıt Geothermal Field (KGF) is located at the northern margin of the Denizli Basin in SW Anatolia (Turkey) where thermal waters discharge along the Quaternary normal fault segments locally displaced by conjugate transfer faults. Major and trace element contents and stable isotopes (δ〈sup〉18〈/sup〉O, δ〈sup〉2〈/sup〉H, δ〈sup〉3〈/sup〉H and δ〈sup〉13〈/sup〉C) of the KGF thermal and cold waters were analyzed in order to determine their origin and evolution and reservoir temperatures. Two main thermal waters, indicated as being fed by steam-heated aquifers, are recognized: (1) Ca-HCO〈sub〉3〈/sub〉 and (2) Ca-SO〈sub〉4〈/sub〉 types. All thermal waters have shown non-equilibrium chemical conditions, indicating mixing processes. According to the δ〈sup〉18〈/sup〉O (−9.14 to −8.07‰) and δ〈sup〉2〈/sup〉H (−59.50 to −51.80‰) data, the KGF thermal waters are meteoric in origin and originated from precipitation in the northern piedmont of Yenice Horst with elevation of 900 m asl. Various geothermometers yield the reservoir temperatures of 80–130 °C. A conceptual flow model for the KGF was suggested as follows: the thermal waters were derived from a regional flow system with high recharge areas and deep circulation depth. The NW- and NE-trending conjugate fault segments (the Pamukkale Fault Zone) serve as features of hydraulic channelling, magmatic heat source and fluid convection in the extensional settings. This fault system is characterized by migration of a large amount of CO〈sub〉2〈/sub〉-rich gas from the deep geothermal reservoir. Consequently, the KGF is characterized by a fault-hosted geothermal system affected by magmatism and active extensional tectonics, the same as other geothermal fields in this crustal extensional setting.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉When it comes to women’s health, treating vaginal infections makes up a high proportion of the gynecological services. Among the forms of vaginitis, vulvovaginal candidiasis (VVC) is considered the second most common. Demand for new treatment alternatives is increasingly relevant, especially for therapies with fewer side effects, better tolerability, and lower cost, while still offering improved quality of life in terms of disease prevention. This study intended to investigate the alternative therapies described for the adjuvant treatment of vulvovaginitis caused by 〈em〉Candida〈/em〉 species, including alternative and complementary treatment methods used by women. This literature review is based on articles written in English and Portuguese in the PubMed, Google Scholar, and SciELO databases. This study was conducted for the most part using the Brazilian Government’s Capes Periodicals Portal, which directs to Google Scholar and PubMed. Since the 1980s, there has been growing interest in alternative therapies in Brazil, a trend which also began in other Western countries in the second half of the twentieth century. Some alternative treatments include substances with antifungal activity, some substances help restore the balance of the vaginal microbiota, while others have an inhibitory activity on microbial virulence factors. The proper use of therapeutic alternatives can effectively contribute to the treatment of VVC, but it should be remembered that some chemical products, such as boric acid or vinegar, and even natural products such as propolis, garlic, and tea tree may have undesirable side effects, having not been tested by well-designed clinical studies. Even so, alternative therapies in the treatment of VVC do have support in the scientific literature.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Asymptomatic uropathogenic 〈em〉Escherichia coli〈/em〉 (UPECs) are the leading cause of asymptomatic bacteriuria (ABU) in humans. So this study aimed to identify and characterize ABU UPECs from hospitalized patients of Kolkata, India, with respect to their antibiogram profile, phylogeny, pathogenicity islands, and virulence factor gene acquisition and FimH mutations in comparison to symptomatic UPECs. 〈em〉E. coli〈/em〉 was detected biochemically in 44.44% (20/45) and 32.26% (20/62) of urine culture-positive asymptomatic and symptomatic hospitalized individuals respectively. Ninety-five percent of the asymptomatic isolates were multidrug resistant (MDR) compared to the symptomatic isolates (100%). Significant predominance of unknown phylogroup, pathogenicity island markers (PAI IV536, PAI I CFT073), and distribution patterns of different virulence factor genes respectively was evident among both groups. A significant correlation was observed between both groups of isolates with respect to their antibiotic resistances (except imipenem, amikacin, and nitrofurantoin), prevalence of phylogenetic groups and PAIs, and virulence factor gene (〈em〉fimH〈/em〉, 〈em〉papC〈/em〉, 〈em〉papEF〈/em〉, 〈em〉papGII〈/em〉, 〈em〉iucD〈/em〉, and 〈em〉cnf1〈/em〉) acquisition. Pathoadaptive FimH adhesin mutations, especially hot spot mutation V27A, were detected in 80% asymptomatic isolates mostly reported in symptomatic ones worldwide. Moreover, this is the first study from India that reported incidence of “Unknown” phylogroup, pathogenicity island markers, and potentially pathoadaptive FimH mutations in asymptomatic UPECs isolated from hospitalized patients which further indicated that these ABU 〈em〉E. coli〈/em〉 might have originated from their symptomatic counterparts due to unbridled use of unprescribed antibiotics. Therefore, this study demands antibiotic de-escalation along with regular and intricate monitoring at the molecular level for efficient management of ABU that addresses a major public health concern.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Mutations occurring in viral polymerase gene of hepatitis B virus (HBV) due to the use of nucleos(t)id analogs reduce the activity of the drugs by causing antiviral resistance. In this study, it was aimed to evaluate mutations responsible for drug resistance and drug resistance mutation rates in patients followed up by the diagnosis of chronic hepatitis B (CHB). A total of 318 CHB patients were included in the study. HBV mutations were detected using the INNO-LiPA commercial kit based on the reverse hybridization principle. Drug resistance mutation was detected in 46.86% (149/318) of the patients. The rates of drug resistance were found 36.79% (117/318) for lamivudine resistance, 12.58% (40/318) for entecavir (ETV), and 7.86% (25/318) for adefovir. In 10 patients, the possible tenofovir (TDF) resistance (3.14%) was found. Single-drug and double-drug resistances were detected in 34.59% and in 11.01% of the patients, respectively. Triple drug resistance was detected in only 1.26% of the patients. Unlike various studies in Turkey and in other countries, remarkable resistance to ETV and TDF were found in this study. The high rate of the probable TDF resistance was striking, with 3.14%.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Some strains of the genus 〈em〉Enterococcus〈/em〉 are effective probiotic bacteria if they meet safety and probiotic criteria. In our study, 17 canine enterococci previously selected from a group of 160 isolates based on safety criteria were screened for some functional properties relevant to their use as probiotics. The results of antimicrobial resistance testing showed sensitivity of eleven strains to EFSA recommended antimicrobials. In contrast, the most frequent resistance was observed for cefotaxim (15/17) and oxacillin (13/17). PCR detection of resistance genes (〈em〉vanA〈/em〉, 〈em〉vanB〈/em〉, 〈em〉vanC〈/em〉, 〈em〉tetM〈/em〉, 〈em〉tetL〈/em〉, 〈em〉ermB〈/em〉, and 〈em〉mefA〈/em〉) revealed the presence of 〈em〉mefA〈/em〉 gene in five 〈em〉Enterococcus faecium〈/em〉 strains and 〈em〉vanA〈/em〉 gene in one strain. The production of enzymes commonly associated with intestinal diseases was in general rare (β-glucosidase 2/17, α-chymotrypsin 1/17, 〈em〉N〈/em〉-acetyl-β-glucosaminidase 0/17, and β-glucuronidase 0/17). The measurement of strain survival rate (%) under the conditions simulating gastric (pH 2.5) and bile juices (0.3% bile) showed considerable differences between strains (〈 0.01 to 4.7% after 90 min for gastric juices, 48.0 to 254.0% after 180 min for bile). The concentration of produced 〈span〉l〈/span〉-lactic acid ranged between 83.1 to 119.3 mmol/L after 48 h cultivation depending on the strain. All strains fermented 16 out of 49 different carbohydrates (range from 17 to 23/49). Antimicrobial activity was recorded for two strains against some species of 〈em〉Listeria〈/em〉 sp. and 〈em〉Enterococcus〈/em〉 sp. Finally, two 〈em〉E. faecium〈/em〉 candidates (IK25 and D7) were selected for testing in dogs, and hereafter they could possibly extend the currently limited range of beneficial bacteria of canine origin used as a dietary supplement for dogs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Paclobutrazol, (2RS, 3RS)-1-(4-chlorophenyl)-4, 4-dimethyl-2-(1H-1,2,4-triazol-1-yl) pentan-3-ol, is a plant growth retardant that mainly inhibits gibberellins (GAs) biosynthesis. In agricultural practice, paclobutrazol is applied to arrest vegetative growth so as to increase the reproductive growth of many orchard fruit, as well as grain crops. However, due to its over-application and chemical stability, paclobutrazol accumulates in soil and inhibits the growth of subsequent crops, especially those grown for vegetative purposes. The present study focused mainly on the changes in the soil bacterial community following application of paclobutrazol. Mung bean (〈em〉Vigna radiata〈/em〉) plants were treated with paclobutrazol and cultivated for three consecutive seasons. Soil samples were collected and analyzed by denaturing gradient gel electrophoresis (DGGE) using 16S rDNA gene fragments and clone library analyses. The results obtained through clustering and clonal sequencing analysis showed that the bacterial community was affected by paclobutrazol, and in addition, was more diverse in the third stage of mung bean plant cultivation. The results of the study showed that paclobutrazol affected bacterial composition, and the population of bacteria varied greatly across time.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The aim of this study was to evaluate the contribution of plasmid-mediated genes and efflux to fluoroquinolone resistance in collection of 〈em〉Achromobacter〈/em〉 spp. gathered during a 3-year period. Susceptibility to ciprofloxacin and levofloxacin was tested by disk diffusion and microdilution tests for a collection of 98 〈em〉Achromobacter〈/em〉 spp. clinical isolates. Identification of fluoroquinolone-resistant isolates was performed by sequencing and phylogenetic analyses of the 〈em〉nrdA〈/em〉 gene. Genetic relatedness among resistant isolates was determined by pulsed-field gel electrophoresis (PFGE) analysis. The influence of an H〈sup〉+〈/sup〉 conductor cyanide 〈em〉m〈/em〉-chlorophenyl hydrazone (CCCP) and a resistance-nodulation-division-type efflux pump inhibitor phenylalanine-arginine beta-naphthylamide (PAβN) on minimal inhibitory concentration (MIC) value was evaluated by broth microdilution. The presence of the plasmid-mediated 〈em〉qnrA〈/em〉, 〈em〉qnrB〈/em〉, 〈em〉qnrC〈/em〉, 〈em〉qnrS〈/em〉, and 〈em〉aac-(6′)-Ib-cr〈/em〉 genes was investigated by PCR and sequencing. 〈em〉Achromobacter〈/em〉 spp. isolates that were resistant or intermediately resistant to fluoroquinolones in disk diffusion tests (44/98) were subjected to microdilution. As a result, 20/98 isolates were confirmed to be resistant to ciprofloxacin while 10/98 was resistant to levofloxacin. CCCP decreased twofold MIC value for ciprofloxacin in six isolates and more than 16 times in one isolate, while MIC value for levofloxacin was decreased in all isolates (twofold to more than eightfold). Fluoroquinolone-resistant isolates were identified as 〈em〉A. xylosoxidans〈/em〉 with the 〈em〉nrdA〈/em〉 gene sequencing. PFGE revealed that resistant isolates belonged to seven different genotypes. Ten isolates belonging to four genotypes were positive for the 〈em〉aac-(6′)-Ib-cr〈/em〉 gene. Although resistance to fluoroquinolones was not widespread among analyzed isolates, detected contribution of efflux pumps and the presence of the 〈em〉aac-(6′)-Ib-cr〈/em〉 gene present a platform for emergence of more resistant strains.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The aim of this study was to determine the presence and prevalence of 〈em〉Wolbachia〈/em〉 bacteria in natural population of fleas (Insecta: Siphonaptera) in Turkey, and to exhibit the molecular characterization and the phylogenetic reconstruction at the positive isolates with other species in GenBank, based on 16S rDNA sequences. One hundred twenty-four flea samples belonging to the species 〈em〉Ctenocephalides canis〈/em〉, 〈em〉C. felis〈/em〉, and 〈em〉Pulex irritans〈/em〉 were collected from animal shelters in Kayseri between January and August 2017. All flea species were individually screened for the presence of 〈em〉Wolbachia〈/em〉 spp. by polymerase chain reaction (PCR) targeting the 16S ribosomal RNA gene. According to PCR analyses, 〈em〉Wolbachia〈/em〉 spp. were found prevalent in 〈em〉C. canis〈/em〉 and 〈em〉P. irritans〈/em〉 fleas, while it was not detected in the 〈em〉C. felis〈/em〉 species. Totally, 20 isolates were purified from agarose gel and sequenced with the same primers for molecular characterization and phylogenetic analyses. The sequence analyses revealed 17 polymorphic sites and 2 genetically different 〈em〉Wolbachia〈/em〉 isolates, representing two different haplotypes in two flea species. The distribution patterns, molecular characterization, and phylogenetic status of 〈em〉Wolbachia〈/em〉 spp. of fleas in Turkey are presented for the first time with this study. Understanding of the role of 〈em〉Wolbachia〈/em〉 in vector biology may provide information for developing 〈em〉Wolbachia〈/em〉-based biological control tools.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The groundwater resources potential of Ethiopia is estimated to be about 40 billion cubic meters. Groundwater has been used as the main source of water supply since the 1970s for the main cities, towns and dispersed rural communities across the country, where provision of reticulated surface-water schemes is often expensive because of initial project construction costs and poor water quality. The exponential growth of the urban population and agriculture-led industrial development have resulted in greater attention to groundwater as the potentially cost-effective water supply source. As part of the growing focus on the use of groundwater, the Ethiopian government is currently implementing irrigation projects. One plan involves nine irrigation projects covering an estimated area of 8,000 ha, being developed on a pilot scale, with 9,000 test wells, 28,000 monitoring wells and 14,657 spring improvements. If this unprecedented Ethiopian groundwater-centred development plan is implemented successfully at such a scale, it is highly likely that its success will persuade other Sub-Saharan developing nations to put in place the necessary policies, regulations and investment for infrastructure and capacity development for exploring, exploiting and managing their groundwater resources.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Nitrogen (N) pollution in shallow groundwater within the Jianghan Plain—a depositional basin along the Yangtze River in China—is a serious issue affecting the local water supply. There is little concern regarding temporal variation patterns of groundwater N in regions with intensive groundwater/surface-water interactions thus far. In this study, a 2-year field monitoring program and a set of incubation experiments were jointly applied to characterize the seasonal variation mechanisms of groundwater N. Groundwater monitoring suggested that temporal N variations in monitoring wells of 25 and 10-m depth were correlated with fluctuations in water levels, with lower NH〈sub〉4〈/sub〉-N and higher NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉-N concentrations corresponding to groundwater discharge during the dry season, and with higher NH〈sub〉4〈/sub〉-N and lower NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉-N concentrations corresponding to groundwater recharge during the wet season. Batch sediment incubation experiments showed that buried organic carbon in sediments from the field site could not promote NH〈sub〉4〈/sub〉-N release, but exogenous organic carbon and oxidant input could catalyze organic N mineralization, resulting in NH〈sub〉4〈/sub〉-N release. Nevertheless, NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉-N release was limited in all incubations. Thus, the temporal variation patterns could be divided into (1) groundwater N in type-1 wells (25 and 10 m), controlled by the annual reversal of groundwater flow gradient, which determined whether there was input of exogenous organic carbon or oxidants, ultimately affecting organic N mineralization, denitrification and other transformation processes, and (2) groundwater N in type-2 wells (〈4 m depth), which showed no significant seasonal variation, implying the process is mainly controlled by surface inputs in the shallower subsurface.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Continuous increasing incidence of allergic diseases is calling for identifying early prognostic markers pointing to increased risk of allergy development and establishing protocols for preventive strategies limiting allergy development in predisposed individuals. It is important to better understand the critical events occurring in early postnatal life, especially the interaction of a newborn with microbial compounds important for the maturation of the neonatal immune system and setting immunoregulatory responses as well. Dendritic cells (DC) together with the cytokine microenvironment play an important role in priming of immune responses. The capacity of monocyte-derived DC (moDC) from cord blood of children of healthy and allergic mothers to respond to microbial antigens (〈em〉Escherichia coli〈/em〉 O86 (EcO86) and delipidated 〈em〉Bacillus firmus〈/em〉 (DBF)) was tested by flow cytometry and quantitative real-time PCR. Both EcO86 and DBF were able to promote maturation of moDC, but moDC of children of allergic mothers expressed higher levels of activation markers CD80 and CD83. Increased gene expression of IL-6 and lower expression of indol-amine 2,3 dioxygenase were observed in moDC of neonates of allergic mothers, in comparison to healthy ones. A higher gene expression and an increased presence of activation markers on moDC of newborns of allergic mothers indicate a generally higher reactivity of these cells, possibly enabling easier development of inappropriate immune response after an allergen encounter.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Understanding and modelling the passage of groundwater is important for a wide range of environmental and earth science disciplines. The science of groundwater modelling is mature, and advanced modelling algorithms are routinely implemented, for example via the widely used MODFLOW software. However, for the non-specialist scientist or student, the fundamentals of such software can be difficult to comprehend, whilst the algorithms are arguably too complex to be easily applied for many applications which require integration of a groundwater model with climate, surface-water, soil or ecological data. In this context, a spreadsheet-based groundwater model (A2016), capable of solving transient groundwater behaviour in multiple spatial dimensions, was developed. Inter-comparison tests investigating nine transient groundwater scenarios were performed between MODFLOW, A2016 and the Time-dependent Groundwater Modeling using Spreadsheet Simulation (TGMSS) model. Results demonstrated that A2016 is directly comparable to MODFLOW, with identical hydraulic heads in all model experiments. TGMSS was not able to accurately simulate hydraulic heads for any of the model experiments. A groundwater–lake interaction scenario was identified for which MODFLOW will produce unrealistic results, due to the way conductance beneath lakes is determined. Applying a specified saturated thickness approximation for the region beneath the lake resulted in improved lake–groundwater interactions. A2016 is potentially useful for educational purposes and as a tool for groundwater experiments by non-specialists, as it is modular in nature and incorporates MODFLOW terminology and techniques.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Ordovician aquifer is a typical limestone aquifer associated with Pangzhuang coal mine in North China. The groundwater properties in this area have been investigated, as the aquifer is a major drinking-water source for local people. The hydro-chemical type of the water is Ca-Na-HCO〈sub〉3.〈/sub〉 The bicarbonate concentration (290–428 mg/L) is relatively higher than that of other major anions (SO〈sub〉4〈/sub〉〈sup〉2−〈/sup〉, Cl〈sup〉−〈/sup〉 and CO〈sub〉3〈/sub〉〈sup〉2−〈/sup〉). Three reasons for the high bicarbonate concentration are proposed. Firstly, from geochemical calculations and correlation analysis, this study finds that the high-bicarbonate water results from dissolution of calcite and dolomite. Secondly, the high bicarbonate content is the result of influence from the regional hydrogeology. The study area is located in the recharge and runoff zone of the Ordovician aquifer, which outcrops in the southeastern hills, and the hydraulic connection between the upper and lower aquifers is confirmed in terms of faults and fissures developed from mining. Finally, high values of partial pressure of CO〈sub〉2〈/sub〉 indicate an open carbonate system. Additionally, SO〈sub〉4〈/sub〉〈sup〉2−〈/sup〉 is confirmed as arising from the dissolution of gypsum, even though gypsum is not the major mineral in the aquifer. Inverse geochemical modeling of three cross-section lines provides additional evidence for the geochemical evolution. It also implies that more calcite is dissolved than dolomite. The coupled approach, using multiple evidence from both hydrogeological and hydro-geochemical insights, as well as geochemical modeling, is able to illustrate the groundwater hydro-geochemistry from a more intrinsic perspective.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Climate change has the potential to substantially impact groundwater recharge, groundwater/surface-water dynamics, and surface-water quality. Changes in climate could be manifested as decreasing overall snowpack or an increase in the variability of snowpack year-to-year, and may affect wildfire occurrence and severity. Observed climatic extremes, including abnormal seasonal snowfall (both drought and extreme precipitation) and wildfires, have occurred in recent years in a semi-arid region of the Great Basin in the western United States. These climatic extremes have caused focused groundwater recharge following winters with elevated snowfall (2011 and 2017). Groundwater recharge calculated using the water-table fluctuation method, for periods following the elevated snowfall, was more than 10 times greater than previous studies in the basin that utilized distributed recharge calculation methods. Caution must be exercised when using results of these calculations in subsequent analyses such as groundwater flow modeling, to assure that all required assumptions are met and that calculated recharge rates are spatially applicable. Although water-quality changes due to the elevated snowfall were not evident in the surface-water data, several geochemical constituents (Ba, Ca, K, Mg, Na, pH, and specific conductance) indicated statistically significant concentration differences following a downstream wildfire in the watershed (representing the climatic extreme of drought). Both recharge calculations and statistical evaluations of water chemistry were completed using an easily modified Python script, which could be utilized by water managers to aid in water-resource planning under potentially variable future climatic conditions.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉An understanding of the three-dimensional hydrostratigraphic architecture of a buried valley network, in particular the continuity of permeable units within their fill, is needed to evaluate the resource potential and role of buried valley aquifers in regional groundwater flow. In this study, a facies modeling algorithm within the exploration and production software Petrel was used to construct a geological model of a buried valley network located in the central Peace Region in Northeast British Columbia, Canada. Facies were interpreted using resistivity inversion results from an airborne electromagnetic survey (SkyTEM) and borehole gamma-ray and lithology logs. This detailed geological model and a simplified geological model of the buried valley network were used to develop two interpretive numerical groundwater flow models in MODFLOW. Calibration was performed using baseflow estimates derived using a novel approach whereby upper and lower bounds for baseflow indices were combined with streamflow estimates from the Northeast Water Tool (NEWT), a hydrological modeling tool developed for water allocation for industrial use by the British Columbia Oil and Gas Commission. The modeling results suggest that permeable deposits exist within the buried valleys, but are not regionally connected throughout the whole network, and thus do not play a significant role in the regional groundwater flow regime. However, locally extensive permeable deposits occur within the buried valleys and may offer viable water sources for domestic use or to replace existing surface-water licenses for industrial use.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The natural radioisotope radon (〈sup〉222〈/sup〉Rn) has been widely used as a tracer for quantifying submarine groundwater discharge (SGD). Applicable equipment for continuous radon-in-water detection using a radon-in-air monitor includes the “RAD AQUA” and the “Water Probe” (both Durridge Inc., USA). Although both devices have been applied to measure 〈sup〉222〈/sup〉Rn concentrations in coastal water over time periods from hours to days, the monitoring results for the same water body may differ due to the different physical driving forces for 〈sup〉222〈/sup〉Rn degassing from the water, which will result in an inaccurate SGD estimate. Here the two approaches were simultaneously applied for monitoring 〈sup〉222〈/sup〉Rn concentrations at the same site in the same surface-water body (Daya Bay, China). The SGD fluxes resulting from both approaches were evaluated and compared, based on the obtained time series and a 〈sup〉222〈/sup〉Rn mass balance model. The results demonstrate that the average 〈sup〉222〈/sup〉Rn concentration measured by the Water Probe is only ~30% of that detected by means of the RAD AQUA. The mean SGD flux estimated based on 〈sup〉222〈/sup〉Rn time series measured with the Water Probe is 69% of that detected by means of the RAD AQUA. The findings of this study suggest that the RAD AQUA can capture more accurately the signals of variation of radon concentration, and is a better approach for continuously monitoring radon and quantifying SGD in coastal zones. Thus, previous studies based on 〈sup〉222〈/sup〉Rn data from the Water Probe for estimating SGD and the associated nutrient flux may need re-evaluation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This study evaluates the applicability of the chloride mass balance (CMB) method for groundwater recharge estimation in a semi-arid region in Canada, where recharge largely occurs under topographic depressions. The CMB applicability was tested at three scales: point-scale recharge rates at different topographical positions; average recharge rates incorporating multiple topographical positions on a local scale; and an identification of spatial trends of recharge on a regional scale. Agricultural chloride inputs were shown to be a major factor affecting chloride concentrations at all three scales, where elevated chloride concentrations in the shallow subsurface affected by agricultural inputs surpassed background concentrations by an order of magnitude. The propagation depth of elevated concentrations varied among study sites from being largely confined to the unsaturated zone to extending well into the saturated zone. Lateral chloride redistribution further affected the CMB applicability for point-scale recharge rates. Specific solutions enabling the CMB application in these conditions are presented, including runoff concentration measurements for point-scale estimates, using groundwater age tracers on a local scale, and using the harmonic mean concentration of a large number of samples on a regional scale.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The hydrological dynamics of karstic systems are generally highly nonlinear and weakly predictable. This paper introduces, for the first time, a hydrological modelling approach based on chaos theory. Although this modelling approach may be extended to multi-variables, as a first step in exploring its applicability, the focus is on the simple case of single-variable modelling for karst springs, which in practice corresponds to basins where rainfall is ungauged or poorly constrained. Chaos modelling is applied to the discharge of two karstic springs, the Doubs and the Lez springs in France, selected because they represent very different geological settings, climatic conditions, anthropogenic forcings and discharge dynamics. A deterministic model of autonomous ordinary differential equations is obtained for each spring. The models have chaotic behavior in both cases. The forecasting skills of these chaotic models are assessed. Forecasting performance estimates suggest that, under real conditions, forecasting could be performed for time horizons of ~16 h for Doubs and ~19 h for Lez (±1,000 L/s, 95% of confidence). This analysis offers new evidence for chaos in hydrogeology: the dynamic of discharge of karst springs is both deterministic and highly sensitive to the initial conditions, and it can be approximated by low-dimensional models.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Four bench-scale solute injection experiments were conducted in a natural undisturbed basaltic fractured core of the Serra Geral Formation (SGF) (Brazil) to assess the performance of the equivalent apertures on conservative solute transport. Fracture aperture is particularly important in controlling solute transport in fractured-rock aquifers. The spatial heterogeneity of fracture apertures complicates solute transport modeling. Scientific researchers and mainly hydrogeology professionals still adopt a single value for the fracture aperture field, i.e., an equivalent aperture. However, there is a lack of information about the most suitable equivalent aperture associated with solute transport phenomena, especially for basaltic fractured aquifers. The objective of this study was to evaluate the performance of three types of equivalent apertures on conservative solute transport in a basaltic aquifer sample. The fracture aperture field was measured using the advanced high-resolution and nondestructive technique, x-ray micro-computed tomography. The performance of the equivalent apertures was evaluated using an analytical solution of the one-dimensional advection-dispersion equation (ADE) compared to observed breakthrough curves. As a result, the arithmetic mean of the measured aperture field was 111.74 ± 54.26 μm. The analytical solution of ADE coupled with mass balance aperture was able to predict breakthrough behavior, especially for low volumetric flow rates. This study demonstrates that the mass balance aperture should be adopted as an equivalent aperture instead of the hydraulic and friction loss equivalent aperture when inertial forces of macroscopic flow are negligible. The findings provide a step forward towards better understanding of groundwater contamination risk in basaltic fractured aquifers.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Many coastal areas around the world suffer severe water stresses due to improper management of water resources. In these areas, groundwater is typically the most important source for drinking water, and its overexploitation may lead to deterioration in water quality. In coastal confined aquifers, the dynamics of saltwater intrusion (SWI) and well salinization are the focus of many recent studies that commonly do not include a geological study of the subsurface structure of the aquifer. The goal of the present work is to study the effect of groundwater extraction on SWI, using the Judea Group Aquifer as a case study representing a coastal confined aquifer that suffers drawdown due to excess pumping. First, the offshore-onshore structure of the aquifer is described, and then a groundwater model is constructed based on the inferred structure. The resulting model shows that under realistic conditions, a water well situated 5 km inland from the shoreline is expected to undergo salinization after ~190 years since level drop. The SWI advances inland faster when the confinement is efficient, suggesting that semi-confined aquifers should be preferred for pumping compared with confined ones. Additionally, the model shows that under certain conditions, deep submarine groundwater discharge (SGD) occurs through the aquifer outcrop, ~15 km offshore and at depths of ~200 m. The SGD comprises brackish and warm water. The insights from this work are important both for studies on freshwater budgets in coastal areas and for the study of SGD and its implications for the ocean.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉〈em〉Neoscytalidium〈/em〉 (or 〈em〉N.〈/em〉) 〈em〉dimidiatum〈/em〉 and 〈em〉N. novaehollandiae〈/em〉 are two aggressive plant pathogenic species that affect several agricultural crops. Early detection and identification of these fungi are of critical importance to bring about the effective minimization to the threat they pose to the infected plants. Herein, two species of 〈em〉Neoscytalidium〈/em〉 were rapidly discriminated by utilizing the rRNA internal transcribed (ITS4-5.8S-ITS5) PCR primers. A total of 100 isolates of 〈em〉Neoscytalidium〈/em〉 species, which were isolated from Iraqi canker-infected fig trees, were included in this study. Two discrete electrophoretic PCR bands were observed in 〈em〉Neoscytalidium〈/em〉 isolates—A-variants were about 546 bp, while B-variants were about 993 bp in length. The comprehensive phylogenetic analysis of both DNA variants revealed that A-variants resided between 〈em〉N. novaehollandiae〈/em〉 and 〈em〉N. hyalinum〈/em〉, while B-variants were closely related to 〈em〉N. dimidiatum〈/em〉. Furthermore, the highly specific re-constructed tree of both electrophoretic variants demonstrated that B-variants share a high similarity with 〈em〉N. novaehollandiae〈/em〉. Additionally, the secondary structures for both variants were predicted computationally to reveal the structural patterns that each variant follows. In conclusion, a small rRNA locus comprising 22 nucleotides that differs in the two variants is potentially responsible for this species-specific classification. The main divergence in the amplified loci led to the classification of these fungal variants into two main species, namely 〈em〉N. dimidiatum〈/em〉 and 〈em〉N. novaehollandiae〈/em〉, demonstrating that the amplification by ITS4–ITS5 rRNA fragment is a beneficial strategy that can be employed for the assessment of 〈em〉Neoscytalidium〈/em〉 diversity in the natural ecosystems.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Turkeys and broilers have been identified as important reservoirs for 〈em〉Campylobacter jejuni〈/em〉 which is of public health significance. The evaluation of the genotypes among 〈em〉C〈/em〉. 〈em〉jejuni〈/em〉 strains within different reservoirs is critical for our understanding of the epidemiology of this infectious agent. The present study aimed to compare the genetic diversity and differences of 〈em〉C〈/em〉. 〈em〉jejuni〈/em〉 isolates from turkeys and broilers using flagellin PCR-RFLP typing (〈em〉flaA〈/em〉 typing) technique, in terms of the ease of use and discriminatory power. Sixty 〈em〉C〈/em〉. 〈em〉jejuni〈/em〉 isolates were detected biochemically and confirmed by duplex-PCR from turkeys and broilers (30 strains from each bird species). Then, a 〈em〉flaA〈/em〉 gene fragment (1725 bp) of 〈em〉C〈/em〉. 〈em〉jejuni〈/em〉 isolates was amplified and amplicons were digested with HpyF3I enzyme. Restriction analysis by HpyF3I gave four different 〈em〉flaA〈/em〉 patterns (H1, H2, H3, H4) among all tested 〈em〉C〈/em〉. 〈em〉jejuni〈/em〉 isolates. In broiler isolates, all four patterns were observed but in turkey isolates, only H2 and H4 patterns were present. The results clearly demonstrated that distribution of the 〈em〉flaA〈/em〉 typing patterns differed depending on the host species (broiler/turkey). H1 and H3 〈em〉flaA〈/em〉 types are more prevalent in broiler than turkey isolates, while H2 type is significantly more prevalent within isolates from turkey (〈em〉p〈/em〉 〈 0.05). The 〈em〉flaA〈/em〉 typing technique by digestion with HpyF3I enzyme can almost give us a clue to the source of infection in local outbreaks.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Mixed infections and heteroresistance of 〈em〉Helicobacter pylori〈/em〉 contribute to decreased efficacy of treatments. This study aimed to investigate frequency of clarithromycin heteroresistance and its link with mixed infections, medication history, and disease severity. A total of 40 pairs of 〈em〉H〈/em〉. 〈em〉pylori〈/em〉 strains were isolated from the antrum and corpus of 97 patients. Susceptibility of the strains to clarithromycin was measured by agar dilution method. Site-specific mutations of 〈em〉23S rRNA〈/em〉 at A2143G, A2142G, and A2142C positions were analyzed by PCR and genomic relatedness of pairs of the strains was determined by random amplified polymorphic DNA (RAPD)-PCR. The results showed a prevalence of 35% (14/40) clarithromycin resistance. Diversity of the antrum and corpus isolates in resistance to clarithromycin was detected among 17.5% (7/40) of the patients. Similarly, diversity in MIC value was also detected in two patients infected with the sensitive strains. Significant difference in frequency of resistance was detected among patients with peptic ulcer disease (PUD) (MIC90 32 μg/mL) and severe gastritis (MIC90 16 μg/mL), compared with those who suffered from non-ulcer dyspepsia (NUD) (MIC90 8 μg/mL) and chronic gastritis (MIC90 0.25 μg/mL). MIC values showed 8–32 folds increased levels in the corpus. A2142G, A2143G, and A2142C mutations were detected in three, two, and two patients, respectively, but not observed in 46% of the resistant strains. RAPD-PCR fingerprints showed identical molecular patterns for the isolates of the corpus and antrum in each patient. In conclusion, microevolution of 〈em〉H〈/em〉. 〈em〉pylori〈/em〉 strains during chronic infection, rather than mixed infection, and inappropriate medication appear to be main reasons of treatment failure in adults.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉〈em〉Pediococcus pentosaceus〈/em〉 GS4 (MTCC 12683), a probiotic lactic acid bacterium (LAB), was found to produce bacteriocin in spent culture. Antibacterial and antagonistic potential of this bacteriocin against reference strains of 〈em〉Staphylococcus aureus〈/em〉 (ATCC 25923), 〈em〉Escherichia coli〈/em〉 (ATCC 25922), 〈em〉Pseudomonas aeruginosa〈/em〉 (ATCC 25619), and 〈em〉Listeria monocytogenes〈/em〉 (ATCC 15313) was proven by double-layer and well diffusion methods wherein nisin and ampicillin were used as positive controls. Bacteriocin in supernatant was purified and analyzed by SDS-PAGE, RP-HPLC, and circular dichroism (CD). The physico-chemical properties of purified bacteriocin were characterized being treated at different temperatures (30 to 110 °C), pH (3.0 to 12.0), with different enzymes (α-amylase, pepsin, and lysozyme), and organic solvents (hexane, ethanol, methanol, and acetone) respectively. The molar mass of bacteriocin (named pediocin GS4) was determined as 9.57 kDa. The single peak appears at the retention time of 2.403 with area amounting to 25.02% with nisin as positive control in RP-HPLC. CD analysis reveals that the compound appears to have the helix ratio of 40.2% with no beta sheet. The antibacterial activity of pediocin GS4 was optimum at 50 °C and at pH 5.0 and 7.0. The pediocin GS4 was not denatured by the treatment of amylase and lysozyme but was not active in the presence of organic solvents. This novel bacteriocin thus m ay be useful in food and health care industry.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Accurate estimates of aquifer parameters are necessary for effective groundwater management and for geotechnical engineering applications. Pumping tests may be employed to estimate the hydraulic conductivity in leaky aquifer/aquitard systems. This work introduces a hybrid algorithm with global search capacity (the Genetic algorithm, GA) and local search capacity—the Levenberg-Marquardt (LM) algorithm—coupled with a modified Neuman-Witherspoon solution for leaky aquifers to estimate the aquifer’s hydraulic parameters from pumping-test data. The GA is employed to determine the initial guesses of the aquifer parameter values. The optimal parameter values are then obtained with the LM algorithm, yielding a mixed GA/LM algorithm, herein named GALMA. Results show that the drawdown trends based on the estimated parameters agree well with measured drawdown. The proposed estimation algorithm identifies aquifer parameters with greater reliability than previous approaches. Verification of the GALMA is carried out based on three pumping tests in a layered aquifer in Tianjin, China, and on four historical case studies involving diverse hydrogeological settings. The excellent match between observed drawdown and GALMA-estimated parameters demonstrates the estimation accuracy and superior performance relative to previously reported estimation methods.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Groundwater vulnerability assessment is an effective tool for groundwater pollution prevention and control. However, very few methods are available to address the vulnerability assessment of confined aquifers, though the risk of confined aquifer pollution has been increasing. This paper describes a method that integrates the vulnerability of the unconfined aquifer (〈em〉V〈/em〉), extraction rate (〈em〉E〈/em〉), aquitard thickness (〈em〉B〈/em〉〈sub〉t〈/sub〉), head difference between unconfined and confined aquifers (〈em〉H〈/em〉), aquitard media (〈em〉A〈/em〉〈sub〉t〈/sub〉), and transmissivity of the confined aquifer (〈em〉T〈/em〉〈sub〉c〈/sub〉), i.e., VEBHAT, to assess the vulnerability of confined aquifers. Hydraulic connections between the unconfined and confined aquifers, the vulnerability of unconfined aquifers, and the properties of confined aquifers were explicitly considered in this method. Moreover, the FO-TOPSIS method was used, which integrates fuzzy set theory (FST), along with an optimization model of multi-objective programming (OMP) and the classical TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method, to determine the weights of assessment factors, and to reduce subjectivity of the weight assignment. To illustrate the applicability and reliability of the VEBHAT and FO-TOPSIS methods, they were applied to assess the vulnerability of confined aquifers in Zhaoyuan County, Heilongjiang Province, northeastern China. The Pearson correlation coefficient between the ammonium concentration data and the vulnerability assessment values was used to verify the validity of the methods. The results showed that the VEBHAT method and FO-TOPSIS method could be used to effectively assess the vulnerability of confined aquifers.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A significant volume of an aquifer along the coastline in the German Bight is salinized by seawater intrusion. The mean sea-level rise (MSLR) is expected to continue in the future due to global climatic change, subsequently degrading the fresh groundwater resources. To impede further salinization in the future, a solution is proposed based on weir construction in an existing canal hydraulically connected to the aquifer. The effect is twofold: (1) the elevated groundwater level can upgrade present fresh groundwater resources by shifting the saltwater–freshwater interface position further seaward, or by inhibiting its landward movement, and (2) the inland water level can be elevated, expanding surface water ponds. A fully coupled three-dimensional numerical surface-subsurface model (a modified HydroGeoSphere code) was used to simulate the effects of variable weir construction heights under different MSLR rates, and to quantify the gain of aquifer freshwater volume and loss of usable land due to surface ponding. Construction of a higher weir increases the desalinized aquifer volume and decreases the newly salinized aquifer volume under future MSLR. A minimum height of a weir was determined under a certain MSLR rate to maintain the present freshwater resource. Both weir construction and MSLR can cause the loss of land usage. Computed loss-gain ratio curves can be utilized to determine the optimal weir height, meeting the economic requirements of coastal land management under future MSLR.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The influence of local perched aquifers on groundwater recharge in semi-arid areas at a regional scale remains inadequately studied, especially in southern Africa where data scarcity limits the understanding of recharge and groundwater flow processes. The objective of this study was to understand the interaction between localized perched aquifers and an underlying regional aquifer in the Cuvelai-Etosha Basin in Namibia. The connection between the perched and regional aquifers was assessed based on an extensive dataset of hydrochemical and isotope (δ〈sup〉18〈/sup〉O and δ〈sup〉2〈/sup〉H) measurements for groundwater from both shallow and deep hand-dug wells as well as boreholes. Ephemeral rivers and pans/depression landforms were analyzed separately. Recharge was calculated using the chloride mass balance method. It was found that groundwater originates from precipitation that undergoes strong evapotranspiration and water–rock interaction, especially carbonate dissolution. Overlapping chemical and isotopic compositions suggest a common or similar origin of groundwater in the perched and regional aquifers in the pan/depression hydrotope. No such similarity was established for the ephemeral river hydrotope, suggesting that ephemeral rivers contribute negligibly to regional groundwater recharge. This has important implications for groundwater management and helps to understand recharge processes in similar semi-arid environments.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In semiarid and arid regions, the evaporation from bare soil is highly sensitive to changes in the depth to the water table. This study quantifies the relation between water-table depth and the groundwater contribution to evaporation in the Ordos Basin in China. In-situ field experiments were combined with numerical simulations of heat, vapor and liquid water flow. Based on lysimeter experiments and a calibrated numerical model, a relation between depth to groundwater and evaporation rate was established for the lysimeter site. In addition, a sensitivity analysis considering the hydraulic conductivity and the inverse of the air-entry pressure (van Genuchten 〈em〉α〈/em〉) was established. For the field site, the results showed that for the water-table depths less than 52 cm below the ground, evaporation is independent of the water-table depth. For water-table depths exceeding 52 cm, an exponential relation between depth to groundwater and evaporation is observed. No phreatic evaporation occurs for water tables deeper than 105 cm, which is nearly two times the capillary fringe height. The sensitivity analysis showed that the extinction depth decreased with decreasing hydraulic conductivity and increased with 〈em〉α〈/em〉. The field-specific results and the sensitivity analysis provide valuable information to understand the dynamic processes of soil evaporation in the Ordos Basin. From a methodological point of view, the proposed modelling approach and the integration of lysimeter data proved to be a highly efficient combination to study evaporation dynamics in semi-arid and arid environments.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This study experimentally investigated the internal fracture geometries and hydraulic properties of deformable rock samples subjected to various loading paths. Three loading paths, uniaxial compression, conventional triaxial compression, and triaxial prepeak unloading, were administered to granite samples. A high-precision X-ray microfocus-computed-tomography scanning system was adopted to explore the internal failure modes of the deformable samples, and a series of flow tests with different hydraulic pressures and confining stresses were then performed. The results show that the samples after uniaxial compression exhibit a typical splitting failure mode; however, for conventional triaxial compression and prepeak unloading, the samples generally show tensile-shear failure modes. The relationship between the flow rate and pressure gradient of the sample after uniaxial compression can be best described using the Forchheimer law. Both the linear and nonlinear coefficients in the Forchheimer law increase with increasing confining stress. As the confining stress increases from 4 to 20 MPa, the critical hydraulic gradient that quantifies the onset of nonlinear flow increases from 5.33 to 56.74, but the transmissivity decreases due to the fracture closure. For water flow through the samples after conventional triaxial compression and prepeak unloading, two representative types of nonlinear flow behaviors induced by inertial effects and fracture dilation were observed. Different loading paths lead to different failure mechanisms and thus different fluid-flow responses, and the samples subjected to prepeak unloading with a high confining pressure possess a more significant flow capacity.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The identification of transient groundwater contaminant sources in terms of source locations, contaminant magnitudes, and active durations remains a challenge. The problem becomes more complex due to spatial heterogeneity, sparse observation data, concentration measurement errors, and unexpected uncertainty. This study addresses this challenge by proposing a modified self-organizing maps (SOM) algorithm; this algorithm can improve the physically-based models by reducing the computational burden more efficiently. The method sufficiently increases the accuracy and efficiency for identifying the contaminant source, because the trained SOM-based surrogate models can identify the source characteristics independently without necessarily operating a formal linked simulation-optimization model. The performance of the proposed method was assessed on a hypothetical heterogeneous aquifer model; the assessment considered unknown observation data, concentration measurement errors, and an unknown pumping well. The proposed SOM-based surrogate model can not only approximate the results from the groundwater flow and transport simulation models, but it can also be used in lieu of the optimization model in a more efficient way for identifying the unknown transient contaminant sources in groundwater systems.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The existence of submarine fresh groundwater has been recorded at continental shelves worldwide. The dynamic preservation and lifetime of fresh groundwater in the offshore environment remains an open hydrogeological problem. The mechanisms and time scales of fresh groundwater preservation are examined using numerical simulations based on a geologically representative model of the New Jersey shelf, USA. Utilizing two-dimensional depth-migrated seismic and well data, a detailed hydrogeological model is built, with a vertical resolution of 10 m. The model captures the highly heterogeneous shelf environment and accounts for porosity compaction trends derived from core data. The results show transient coupled simulations of groundwater flow and heat and salt transport from the late Pleistocene until present day and projected 18,000 years into the future. They reveal freshwater preservation patterns and yield simulated borehole salinity profiles broadly consistent with field observations. The simulations show that freshwater intervals of a thickness of 200–300 m and lateral extent of tens of kilometers may have been preserved from the Last Glacial Maximum until today. It was found that approximately 30–45% of the initial freshwater volume remains preserved after 12,000 years, depending on the recharge boundary condition. The preserved volume ranges between 15 and 30% after 30,000 years. These results improve the understanding of submarine preservation of fresh groundwater through an interdisciplinary approach which integrates seismic imaging, hydrogeological modeling and high-performance numerical simulation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The interaction between a waterproof curtain and withdrawal wells (or simply, the wall-well effect) is a key factor in controlling the environmental effects that occur during the dewatering of foundation pits. A series of laboratory investigations was conducted to study the changes in groundwater level during dewatering. The influence of the buried depth of the waterproof curtain placed in a dewatering confined aquifer (〈em〉D〈/em〉), and the filter length of the pumping well (〈em〉L〈/em〉), is investigated. Based on the laboratory test results, numerical simulations are used to analyse the ground settlement. The relationship between the approximate hydraulic gradients on both sides of the wall (Δ〈em〉i〈/em〉), or the ground settlement outside the excavation (〈em〉S〈/em〉), using ratio 〈em〉R〈/em〉〈sub〉〈em〉D〈/em〉〈/sub〉 (〈em〉D〈/em〉 divided by the thickness of the confined aquifer) or ratio 〈em〉R〈/em〉〈sub〉〈em〉L〈/em〉〈/sub〉 (〈em〉L〈/em〉 divided by the thickness of the confined aquifer), can be simulated using a Boltzmann curve. The value of Δ〈em〉i〈/em〉 increases while 〈em〉S〈/em〉 decreases with an increase in 〈em〉R〈/em〉〈sub〉〈em〉D〈/em〉〈/sub〉, whereas Δ〈em〉i〈/em〉 decreases while 〈em〉S〈/em〉 increases with an increase in 〈em〉R〈/em〉〈sub〉〈em〉L〈/em〉〈/sub〉. The value of the contraflexure point of the Boltzmann curve is regarded as the effective value of 〈em〉R〈/em〉〈sub〉〈em〉D〈/em〉〈/sub〉 or 〈em〉R〈/em〉〈sub〉〈em〉L〈/em〉〈/sub〉. Based on a comprehensive consideration, 〈em〉R〈/em〉〈sub〉〈em〉D〈/em〉〈/sub〉 is suggested to be equal to or larger than the effective value, and 〈em〉R〈/em〉〈sub〉〈em〉L〈/em〉〈/sub〉 is suggested to be equal to or lesser than the effective value.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The need for regional-scale integrated hydrological models for the purpose of water resource management is increasing. Distributed physically based coupled surface-subsurface models are usually complex and contain a large amount of spatio-temporal information that leads to a relatively long forward runtime. One of the main challenges with regard to regional-scale inverse modeling relates to parameterization and how to adequately exploit the information embedded in the existing observational data while avoiding parameter identifiability issues. This study examined and compared the calibration of a “highly parameterized” model with a “classical” unit-based parameterization scheme in which the dominant geological features were assumed to be known. The physically based coupled surface-subsurface model MIKE SHE was used for conducting the study of five river basins (4,900 km〈sup〉2〈/sup〉) in central Jutland in Denmark, characterized by heterogeneous geology and a considerable amount of groundwater flux across topographical catchment boundaries. The results indicated that introducing more flexibility in the parameter estimation process through a regularized approach significantly improved the model performance, in particular head and water balance errors. The highly parameterized calibration results additionally provided very useful insights into the model deficiencies in terms of conceptual model structure and incorrectly imposed boundary conditions. Furthermore, the results from data-worth analysis indicated that the highly parameterized model has more effectively utilized the information in the dataset compared to a traditional unit-based calibration approach.〈/p〉

Description: 〈p〉There was an error during production which resulted in the alpha symbol (〈em〉α〈/em〉) being omitted from the article in some locations.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Upsurge in the instances of antibiotic-resistant uropathogenic 〈em〉Escherichia .coli〈/em〉 (UPECs) strains has repositioned the attention of researchers towards a century old antimicrobial approach popularly known as phage therapy. Rise of extended spectrum beta lactamase (ESBL) and biofilm producing strains has added another step of hurdle in treatment of uropathogens with conventional antibiotics, thus providing a further impetus for search for exploring new therapeutic measures. In this direction, bacteriophages, commonly called phages, are recently being considered as potential alternatives for treatment of UPECs. Phages are the tiniest form of viruses which are ubiquitous in nature and highly specific for their host. This review discusses the possible ways of using natural phages, genetically engineered phages, and phage lytic enzymes (PLEs) as an alternative antimicrobial treatment for urinary tract infections. The review also sheds light on the synergistic use of conventional antibiotics with phages or PLEs for treatment of uropathogens. These methods of using phages and their derivatives, alone or in combination with antibiotics, have proved fruitful so far in in vitro studies. However, in vivo studies are required to make them accessible for human use. The present review is a concerted effort towards putting together all the information available on the subject.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Homeostatic mechanisms preventing the toxicity of heavy metal ions in cells involve, among others, compartmentalization and binding with peptidaceous ligands, particularly the cysteinyl-rich metallothioneins (MTs). We have previously shown that in natural conditions Zn-overaccumulating ectomycorrhizal (EM) fungus 〈em〉Russula bresadolae〈/em〉 stores nearly 40% of Zn bound with cysteinyl- and hystidyl-containing RaZBP peptides, which resemble MTs, while the detoxification of Zn and Cd in EM 〈em〉Hebeloma mesophaeum〈/em〉 relies upon compartmentalization in small vesicles and vacuoles, respectively. Here, we examined the performance of Ra〈em〉ZBP1〈/em〉 gene expressed in 〈em〉H. mesophaeum〈/em〉 mycelium with respect to handling of Zn and Cd. Expression of Ra〈em〉ZBP1〈/em〉 impaired growth of the mycelium on low-Zn medium by 60%, the growth was partly ameliorated upon the addition of Zn and remained considerable up to 2 mmol/L Zn, while the growth of the wild-type and control mycelia transformed with empty T-DNA was severely reduced in the presence of 0.5 mmol/L Zn; furthermore, Ra〈em〉ZBP1〈/em〉 slightly added to Cd tolerance in the range of Cd concentrations of 0.625 to 8 μmol/L. Staining of Zn- or Cd-exposed hyphal cells with Zn- or Cd-specific fluorescent tracers did not indicate that the expression of Ra〈em〉ZBP1〈/em〉 would redirect the flow of the metals away from their innate sinks. Size exclusion chromatography of extracted metal species revealed that the complexes corresponding to Zn/Cd-RaZBP1 are present only in minute levels. Considering that RaZBP1 inhibited growth at low Zn, and despite the benefit that it provided to 〈em〉H. mesophaeum〈/em〉 in the presence of high Zn and moderate Cd, these data indicate that the binding of excess Zn and Cd with RaZBP1 is not a trait that would be outright transmitted to 〈em〉H. mesophaeum〈/em〉.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉We have worked out a rapid 1-day test based on photosynthesis measurements to estimate suitable growth temperature of microalgae cultures. To verify the proposed procedure, several microalgae—〈em〉Chlorella〈/em〉, 〈em〉Nostoc〈/em〉, 〈em〉Synechocystis〈/em〉, 〈em〉Scenedesmus〈/em〉, and 〈em〉Cylindrospermum—〈/em〉were cultured under controlled laboratory conditions (irradiance, temperature, mixing, CO〈sub〉2〈/sub〉, and nutrient supply) to find the optima of photosynthetic activity using the range between 15 and 35 °C. These activities were recorded at each temperature step after 2 h of acclimation which should be sufficient as oxygen production and the PQ cycle are regulated by fast processes. Photosynthetic activity was measured using three techniques—oxygen production/respiration, saturating pulse analysis of fluorescence quenching, and fast fluorescence induction kinetics—to estimate the temperature optima which should correspond to high growth rate. We measured all variables that might have been directly related to growth—photosynthetic oxygen evolution, maximum photochemical yield of PSII, 〈em〉F〈/em〉〈sub〉v〈/sub〉/〈em〉F〈/em〉〈sub〉m〈/sub〉, relative electron transport rate rETR〈sub〉max〈/sub〉, and the transients 〈em〉V〈/em〉〈sub〉j〈/sub〉 and 〈em〉V〈/em〉〈sub〉i〈/sub〉 determined by fast fluorescence induction curves. When the temperature optima for photosynthetic activity were verified in growth tests, we found good correlation. For most of tested microalgae strains, temperature around 30 °C was found to be the most suitable at this setting. We concluded that the developed test can be used as a rapid 1-day pre-screening to estimate a suitable growth temperature of microalgae strains before they are cultured in a pilot scale.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this work, the key moments of the development of the so-called thin-layer cascades (TLC) for microalgae production are described. Development started at the end of the 1950s when the first generation of TLCs was set-up in former Czechoslovakia. Since, similar units for microalgae culturing, which are relatively simple, low-cost and highly productive, have been installed in a number of other countries worldwide. The TLCs are characterized by microalgae growth at a low depth (〈 50 mm) and fast flow (0.4–0.5 m/s) of culture compared to mixed ponds or raceways. It guarantees a high ratio of exposed surface to total culture volume (〉 100 1/m) and rapid light/dark cycling frequencies of cells which result in high biomass productivity (〉 30 g/m〈sup〉2〈/sup〉/day) and operating at high biomass density, 〉 10 g/L of dry mass (DW). In TLCs, microalgae culture is grown in the system of inclined platforms that combine the advantages of open systems—direct sun irradiance, easy heat derivation, simple cleaning and maintenance, and efficient degassing—with positive features of closed systems—operation at high biomass densities achieving high volumetric productivity. Among significant advantages of thin layer cascades compared to raceway ponds are the operation at much higher cell densities, very high daylight productivities, and the possibility to store the culture in retention tanks at night, or in unfavourable weather conditions. Concerning the limitations of TLCs, one has to consider contaminations by other microalgae that limit cultivation to robust, fast-growing strains, or those cultured in selective environments.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Due to limitations in commercial diagnostic methods, this study aimed to develop a reliable real-time polymerase chain reaction (Rt-PCR) assay for early diagnosis of brucellosis. Optimization of the Rt-PCR method was performed on serum samples spiked by 〈em〉Brucella melitensis〈/em〉 with different densities ranging from 10〈sup〉1〈/sup〉 to 10〈sup〉8〈/sup〉 colony-forming units (cfu)/mL; each density was prepared in ten samples. The limit of detection was investigated by using Thermo DNA extraction kit with Maxima SYBR Green Rt-PCR and two TaqMan probe–based Rt-PCR protocols performed by QuantiTect and TEMPase multiplex PCR master mixes in two thermal cyclers, which were Rotor-Gene and Bio-Rad. The validation of the optimized protocol was carried on 20 brucellosis-negative samples and 20 samples spiked with 〈em〉B. melitensis〈/em〉 by using a combination of Thermo DNA extraction kit with TEMPase PCR master mix. SYBR Green Rt-PCR yielded positive results on all samples having ≥ 10〈sup〉4〈/sup〉 cfu/mL of 〈em〉B. melitensis〈/em〉 in both thermal cyclers. Its limit of detection was 112 DNA copies per reaction. The positivity of both probe-based Rt-PCR protocols was 100% and 80% on the samples having 10〈sup〉3〈/sup〉 cfu/mL and 10〈sup〉2〈/sup〉 cfu/mL of 〈em〉B. melitensis〈/em〉, respectively. The limit of detection of probe-based protocols was defined as 4 DNA copies per reaction. The optimized Rt-PCR protocol showed high-level accuracy, precision, specificity, and sensitivity, each having a rate of 100%. The current study indicated that the TaqMan probe–based Rt-PCR protocol optimized and validated with serum samples can be reliably used for early diagnosis of brucellosis.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The edge of regional aquifers can be complex hydrodynamic systems with unique flow dynamics, water quality, and continuity relationships with the main aquifer system. A site near the southwestern margin of the High Plains Aquifer (USA) was investigated to characterize the local hydrogeology and its relationship with the regional aquifer system. Measurements of tritium, ion concentrations, oxygen and hydrogen isotopes, and hydraulic heads documented (1) a discontinuous saturated zone, (2) no inflow to the study area from the regional aquifer, (3) focused recharge beneath playas with limited local mixing between pockets of saturation, (4) outflow orthogonal to the regional aquifer flow direction, (5) localized multi-year reversals in flow direction following high precipitation events, and (6) a magnified influence of the paleo-erosional surface of the basement rock (Dockum Group) on groundwater isolation and flow direction. In isolated areas, groundwater can be trapped on decadal time scales by depressions in the Dockum, or by recharge events that periodically reverse groundwater gradients.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In most arid areas, due to scarce hydrogeological data, it is a challenge to locate groundwater sources and to meet water demand for residential, irrigation, and mining uses. In this study, an innovative method is presented, using magnetic resonance sounding (MRS), to detect areas suitable as groundwater sources on the Mongolian Plateau. First, a target investigation area was identified with a small number of MRS surveys of potential areas by determining whether aquifers exist, whether the aquifers have relatively large water contents and relaxation times, and whether there are hydraulic connections among the aquifers. Next, an intensive MRS survey (158 points in total) was conducted in the target investigation area, and eight boreholes were drilled. A comparison of the borehole data and MRS data showed that when the MRS data had a high signal-to-noise ratio, the aquifer depth and transmissivity estimated by MRS were associated with a deviation of only 4.85 m from the measured depth, and an uncertainty in transmissivity of 15.53%, respectively. These values indicated that the proposed method is highly accurate. Finally, a kriging interpolation method was used to construct distribution maps of groundwater levels, aquifer thickness, transmissivity, and water yield, based on the borehole and MRS data. The reliability of the results was assessed from several perspectives. The findings showed that this step-by-step approach is an effective method of groundwater source detection in arid areas with scarce hydrogeological data.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A hydro-economic approach for planning on-farm managed aquifer recharge is developed and demonstrated for two contiguous sub-basins in California’s Central Valley, USA. The amount and timing of water potentially available for recharge is based on a reoperation study for a nearby surface-water reservoir. Privately owned cropland is intermittently used for recharge with payments to landowners that compensate for perceived risks to crop health and productivity. Using all cropland in the study area would have recharged approximately 4.8 km〈sup〉3〈/sup〉 (3,900 thousand acre-feet) over the 20-year analysis period. Limits to recharge effectiveness are expected from (1) temporal variability in recharge water availability, (2) variations in infiltration rate and few high-infiltration recharge sites in the study area, and (3) recharged water escaping from the study area groundwater system to surface water and adjacent sub-basins. Depending on crop tolerance to ponding depth, these limitations might be reduced by (1) raising berm heights on higher-infiltration-rate croplands and (2) creating dedicated recharge facilities over high-infiltration-rate sites.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Springs in the Middle Atlas region of Morocco are important public water supplies, but their responses to storm-event and seasonal forcings have received only limited study. From March 2014 to May 2015, water temperature was measured hourly at three springs (Ribaa, Sidi Rached, and Zerouka); water level (stage) was measured hourly at Sidi Rached and Zerouka; and maximum daily turbidity was recorded at Ribaa. From March 2014 to March 2015, daily water samples were taken at Zerouka for analyses of deuterium and oxygen-18. Hourly weather data (precipitation and air temperature) were available from March 2014 to May 2015 from Ifrane, near Zerouka. Temperature responses varied between the springs, showing a time-lagged seasonal signal at Sidi Rached, near-constant values at Zerouka, and relatively stable dry-season values followed by flashy wet-season behavior at Ribaa. Stage at Sidi Rached and Zerouka tracked together, with a broad minimum in late summer and responses to individual storms superposed on the signal. Stable isotopes fluctuated daily but were frequently out of phase with each other. Autocorrelation analyses of spring parameters indicate that Sidi Rached and Zerouka have greater inertia than Ribaa. Cross-correlation analyses show characteristic time lags between (1) precipitation and stage, (2) air temperature and water isotopes, and (3) air and water temperatures. However, as shown in previous work, there is a broad range of time lags between precipitation and turbidity. The variety of spring behaviors is consistent with differences in hydraulic connectivity within each spring basin.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Dryland inland freshwater lenses (IFLs) that have been topographically induced are represented using physically modeled laboratory simulations, to characterize the stages of IFL evolution (i.e. formation, migration, degradation) as a function of recharge rate. Arid regions with shallow brackish to saline groundwater possess IFLs. The position and geometry (i.e. thickness, length) of IFLs over varying temporal and spatial scales is poorly understood due to their transient nature. The physically modeled IFLs in this study formed from an initial recharge pulse, after which IFL geometry was measured over time as it flowed in the direction of simulated groundwater flow. The time required for an IFL to reach the maximum thickness exhibited a negative exponential correlation to recharge rate. At IFL formation, thickness and length were positively correlated, and the ratio of IFL thickness to length exhibited a positive exponential correlation to recharge rate. After IFL formation, the central position of the simulated IFLs migrated laterally in the direction of groundwater flow at a velocity less than the range of applied recharge rates and greater than the groundwater flow velocities. The time required for the IFL to reach a minimum thickness, or IFL degradation, exhibited a positive exponential correlation to recharge rate. The Dupuit-Ghyben-Herzberg solution used to model coastal freshwater lens thickness was tested against the physically modeled IFLs and deemed invalid. A correction factor and modified solution are provided to predict IFL thickness, providing motivation for future analytical and numerical studies on inland variable-density groundwater systems in arid regions globally.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉There is a need for groundwater modelling approaches that can incorporate both the complexity of riverbeds and the influence of lateral flows through the river banks in the simulation of river–aquifer interaction. A simple and straight-forward approach is proposed for modelling river–aquifer interaction in gaining rivers based on existing building blocks available in MODFLOW. The river water itself is modelled as constant-head cells, while the riverbed is modelled as one or more separate layers. The Horizontal Flow Barrier (HFB) Package is used to simulate the effect of a river bank on lateral exchange fluxes between river and aquifer. This approach has several advantages over conventional MODFLOW streamflow packages: (1) riverbeds can be modelled as several layers with different hydraulic properties; (2) both vertical and horizontal flow through the riverbed can be modelled; and (3) lateral flow through the river banks can be simulated. The capabilities of the new approach are demonstrated in two applications based on a MODFLOW model of the Aa River, Belgium. Application I demonstrates that the approach can be used to model heterogeneous multi-layered riverbeds. Results show that neglecting this heterogeneity can result in an overestimation of river–aquifer exchange fluxes. Application II shows that the approach can be used to simulate the effect of lateral fluxes through river banks. It demonstrates that lateral fluxes can be a major contributor to total river–aquifer exchange fluxes. The proposed approach provides the necessary tools to accurately model river–aquifer interaction for gaining rivers in MODFLOW.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Tritium is a well-known tracer, used to estimate the age of modern groundwater (〈50 years) and consequently to capture information on the longer-term components of recharge in aquifers. However, its current low concentration in groundwater limits its usefulness for recharge assessment, which is more symptomatic of arid and semi-arid regions where the recharge is characterized by extreme spatial and temporal variability. Regions where groundwater tritium was studied at a time close to the peak of nuclear bomb testing (1963) would be worth studying again today to establish new information. This report describes the application of a radioactivity decay model to a long (up to 50 years) record of tritium in rainfall and the associated recharge to several aquifers in central Tunisia; these aquifers were sampled for tritium in 1967. The results show that the groundwater renewal rate has a large range: 0.06–2.2% of annual mean rainfall for Plio-Quaternary aquifers, 0.1–6.46% for Mio-Pliocene aquifers, and 0.1–1.5% for the upper Oligocene aquifers. A good agreement was found between the recharge estimated in this study and the recharge estimated in previous studies only for the upper Oligocene aquifers. This suggest that the methodology of recharge estimation, described in this report, is reliable only for aquifers of homogeneous lithology with a localized recharge area, but the method is less consistent for detrital aquifers, i.e. composed of lenticular sediments. The results also highlight the usefulness of historical (1950–1970) measurements of tritium in groundwater for the estimation of the groundwater recharge.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The effects of groundwater depletion may impose costs on many people that rely upon the resource. Such costs are not borne entirely by the high-volume pumpers that largely create the problematic conditions. Ideally, sustainable groundwater management should include addressing economic externalities and social equity, although information quantifying these concerns is often unavailable. This work estimates impacts to domestic water well owners from groundwater overdraft caused mostly by pumping deeper agricultural wells. A study is presented for Tulare County in the southern Central Valley of California, USA, where many interruptions in domestic well supplies occurred during a recent drought. The case has unusually well-documented conditions and data available for analysis. A method is developed to model supply interruptions and estimate costs for maintaining domestic water well supplies that are impacted by declining groundwater levels. The analysis is performed in the context of planning for sustainable groundwater management and suggestions for managing the economic externality are made. This work may provide a basis for evaluating the economic impacts on well owners from over-pumping in basins outside the study area where less data may be available.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The Kasserine Aquifer System (KAS) is a transboundary aquifer, located in an arid region in central Tunisia and extending into northeastern Algeria. The system consists of four compartments: Oum Ali-Thelepte, Feriana-Skhirat, and the Plateau and the Plaine of Kasserine. The challenge of this study was to evaluate the influence of regional faults on groundwater flow in the different compartments of the KAS and to estimate the regional impact of current and future groundwater use. A three-dimensional saturated regional groundwater flow model for the steady state and transient conditions (1980–2015) was created and calibrated. This work was achieved using numerical flow modelling, coupled with geological modelling, using FEFLOW and GeoModeller software. The significance of regional faults as potential barriers or conduits to groundwater flow in the different aquifer compartments was evaluated by considering the different recharge rates. Two connectivity hypotheses were proposed at each major fault, and the general hydraulic relationship of units that are juxtaposed by each fault were considered. This study contributes rigorous estimates for the diffuse and concentrated recharge in the arid study region, and evaluates the groundwater behavior that shows a gradual decline in the water table over time, using a regional model. Different predicted outcomes for the KAS based on variable potential groundwater extraction scenarios for the period 2015–2050 have been developed. The results of numerical simulation provide useful information regarding the behavior of the KAS aquifers, and contribute significant knowledge to guide sustainable practice for present and future groundwater management.〈/p〉