Negative Water Balance Research Articles

Features of current and intensive therapy of new coronavirus infection in children with comorbidities (clinical cases)

The risk of a severe course of new coronavirus infection(COVID-19) due to the development of acute respiratory distress syndrome is extremely high, which is especially true forpatients with comorbidities.The aimof the study is to demonstrate the peculiarities ofthe course and intensive care measures in new coronavirusinfection COVID-19 in children with comorbidities.Patients and methods:On the example of clinical cases,the characteristics of the course of a new coronavirus infection of COVID-19 in children with systemic lupus erythematosus and bronchopulmonary dysplasia are considered.Results:The main data from the history and clinical laboratory examination are reflected, which made it possible toidentify a cytokine storm in a timely manner, a high risk ofadverse course and begin timely specific pathogenetic therapy, including immunoglobulins for intravenous administration, hydroxychloroquine, ritonavir in combination withlopinavir, azithromycin and dexamethasone. Particular attention is paid to the need to limit infusion therapy, maintaina negative water balance and optimal blood oxygen capacity,ambiguity of opinions on the need for routine use of albuminand dexamethasone solutions in patients with COVID-19 hasbeen demonstrated.Conclusion:Children with comorbidities are characterized by a severe course of a new coronavirus infection COVID-19, which requires timely pathogenetic therapy takinginto account the individual characteristics of the patient.

Ecophysiological Traits of Invasive C3 Species Calotropis procera to Maintain High Photosynthetic Performance Under High VPD and Low Soil Water Balance in Semi-Arid and Seacoast Zones.

The evergreen C3 plant Calotropis procera is native to arid environments. Thus, it grows under high vapor pressure deficit (VPD), intense light, and severe drought conditions. We measured several ecophysiological traits in C. procera plants growing in semi-arid and seacoast environments to assess the attributes that support its photosynthetic performance under these contrasting conditions. Gas exchange analysis, primary metabolism content, nutrients, the antioxidant system, and leaf anatomy traits were measured under field conditions. In the semi-arid environment, C. procera was exposed to a prolonged drought season with a negative soil water balance during the 2 years of the study. Calotropis procera plants were exposed to a positive soil water balance only in the rainy season in the seacoast environment. The leaves of C. procera showed the same photosynthetic rate under high or low VPD, even in dry seasons with a negative soil water balance. Photosynthetic pigments, leaf sugar content, and the activity of antioxidant enzymes were increased in both places in the dry season. However, the anatomical adjustments were contrasting: while, in the semi-arid environment, mesophyll thickness increased in the driest year, in the seacoast environment, the cuticle thickness and trichome density were increased. The ability to maintain photosynthetic performance through the seasons would be supported by new leaves with different morpho-anatomical traits, with contrasting changes between semi-arid and seacoast environments. Furthermore, our results suggest that an efficient antioxidative system and leaf sugar dynamics can contribute to protecting the photosynthetic machinery even under severe drought.

INFLUENCE OF SOIL TEXTURE, CLIMATE AND VEGETATION COVER ON SECONDARY SOIL SALINIZATION IN PAMPAS PLAINS, SOUTH AMERICA

Land-use change from herbaceous to woody cover -or vice versa- largely affects water fluxes, which in turn can mobilize existing salts dissolved in the soil, and thereby negatively affect soil and/or water quality and site productivity. Secondary salinization was observed after afforestation at the Northern and Eastern subregions of the Río de la Plata Grassland. Based on this, our objective was to determine the degree of association between the climatic (e.g. water balance), edaphic (e.g. texture, presence of petrocalcic horizons) and biological factors (age of plantation, stand density and stand basal area) with the secondary salinization processes under the particular environmental conditions of the Austral Pampas. The lowest electrical conductivity (EC, µS.cm-1) values were found in sites with sandy-textured soils and negative water balance, regardless of tree canopy cover. When EC differences did occur between land uses of the same site (50% of the sites), in most cases - but not in all of them - the highest EC was measured under tree cover. When salinization was significant, no pattern was observed in the salt distribution along the soil profile. An increase of EC was associated with the oldest-unmanaged plantations, with mean age of 40 years, a period much longer than the productive rotation recommended. Under similar edaphic conditions where salinization was observed (i.e. clayed soils, with naturally high salt level), salinization was not significant in relatively young plantations (<rotation period), demonstrating the key role of forest management to decrease its negative impacts on soils.

State-of-the-art of tools and methods to assess vine water status

Rising global air temperatures will lead to an increased evapotranspiration and altered precipitation pattern. In many regions this may result in a negative water balance during the vegetative cycle, which can augment the risk of drought and will require mitigation strategies. These strategies, ultimately, will mean the installation of irrigation systems in some winegrowing regions where vines were cultivated historically under rain-fed conditions and growers do not have many years of experience with vine water management.This review aims to provide a state-of-the-art summary of the recent and most important literature on vine water assessment for monitoring and adapting vineyard management strategies to production goals in view of global warming. Plant, soil and atmospheric methods are reviewed, and their advantages and drawbacks are discussed. Recent advances in plant water status measurement reveal the limitation of traditional techniques such as water potential, particularly in the context of drought and high vapor pressure deficit and the discoveries regarding hydraulic and stomatal regulation. New technologies can integrate heterogeneous sources of information collected in the vineyard at different spatial and temporal resolutions. Such new approaches offer new synergies to overcome limitations inherent to plant water status measurement techniques obtained directly or indirectly from proxy measurements.

Drought and Desertification in Iran

Iran has different climatic and geographical zones (mountainous and desert areas), mostly arid and semi-arid, which are suffering from land degradation. Desertification as a land degradation process in Iran is created by natural and anthropogenic driving forces. Meteorological drought is a major natural driving force of desertification and occurs due to the extended periods of low precipitation. Scarcity of water, as well as the excessive use of water resources, mainly for agriculture, creates negative water balances and changes in plant cover, and accelerates desertification. Despite various political measures having been taken in the past, desertification is still a serious environmental problem in many regions in Iran. In this study, drought and aridity indices derived from long-term temperature and precipitation data were used in order to show long-term drought occurrence in different climatic zones in Iran. The results indicated the occurrence of severe and extremely severe meteorological droughts in recent decades in the areas studied. Moreover, the De Martonne Aridity Index (IDM) and precipitation variability index (PVI) showed an ongoing negative trend on the basis of long-term data and the conducted regression analysis. Rapid population growth, soil salinization, and poor water resource management are also considered as the main anthropogenic drivers. The percentage of the rural population in Iran is decreasing and the urban area is growing fast. Since the 1970s, the usage of groundwater in Iran has increased around fourfold and the average annual decrease in the groundwater table has been around 0.51 m. The results of the study provide a better ex-post and ex-ante understanding of the occurrence of droughts as key driving forces of the desertification in Iran. Additionally, they can enable policymakers to prepare proper regional-based strategic planning in the future. Desertification cannot be stopped or managed completely, but could be mitigated by the adoption of some proposed sustainable land management strategies.

THE FACTOR OF DEGRADATION AND DIRECTIONS FOR THE PERFORMANCE OF THE SOILS OF THE SOUTH STEPHEN OF UKRAINE

The article presents the results of perennial investigations in the field of causes of degradation anddesertification of the irrigated soils of Southern Steppe of Ukraine, scientifically substantiated measuresdirected to decrease of degradation and reconstruction of the soils fertility. The methodological basis ofthe investigations is made up by the modern methods of scientific research: historical, system analysisand approach, economic, statistical, and graphical methods. The natural and anthropogenic factors ofinfluence on the processes of degradation and desertification of the soils are determined. It was proved thatone of the causes of degradation is their natural dryness, which is accompanied by lack of precipitation,negative water balance, and connected with it specific process of soil formation. The measures of the soilfertility conservation are substantiated. The example of practical use of the results of the investigationsin State Enterprise Research Farm «Askaniiske» of the Institute of Irrigated Agriculture of the NAAS isgiven. The developed measures of the soils fertility conservation allow to prevent their degradation, providethe non-deficient balance of humus, increase the efficiency of agricultural activity on the irrigatedlands, improve ecological state of agricultural landscapes, and solve an important state task of providingfood safety as a component of the national safety of Ukraine.

Using stable isotopes paired with tritium analysis to assess thermokarst lake water balances in the Source Area of the Yellow River, northeastern Qinghai-Tibet Plateau, China

A spatially distributed network of thermokarst lakes undergoing significant environmental changes was sampled in 2014 and 2016 to develop a comprehensive understanding of lake water balances in lakes across a gradient of frozen ground conditions. Frozen ground ranges from seasonally frozen ground (SFG) to sporadic discontinuous permafrost (SDP) to extensive discontinuous permafrost (EDP), and is representative of complex conditions in the Source Area of the Yellow River, northeastern part of Qinghai-Tibet Plateau. Radioactive and stable water isotopes in reference lakes (non-thaw lakes), thermokarst lakes, precipitation, wetlands, ground ice and supra-permafrost groundwater are analyzed to characterize systematic variations and to assess lake water balances using stable isotope mass balance (IMB). IMB, paired with analysis of tritium decay gradients, is shown to be a valid approach for detecting short-term shifts in lake water balance, which allows evaluation of the proportion of precipitation-derived versus permafrost-derived water inputs to lakes. All lakes except EDP thaw lakes are evaporation-dominated (E/I > 0.5). Negative water balances occurred most frequently in reference lakes due to hydrological connectivity with rivers. Precipitation-derived water inputs result in positive water balances in SFG and SDP thermokarst lakes, but negative-trending water balances are found in SDP thermokarst lakes due to substantial reduction in water yield. Increasing contributions from thawing permafrost in EDP thermokarst lakes result in strong positive water balance. Permafrost degradation may also lead to the changes in hydrological connectivity between precipitation and wetlands or thermokarst lakes. Based on these findings, a conceptual model of the hydrological evolution of thermokarst lakes under the influence of permafrost degradation is proposed.

Economic and Environmental Impacts of Cropping Pattern Elements Using Systems Dynamics

Tragedies arising from poor water resources management and planning are significantly more relevant than climate change and frequent natural droughts, especially in arid and semi-arid areas. Nearly 92% of total water is allocated to the agricultural sector in Iran. In this situation, cultivation patterns play an important role in agricultural water management. Evaluating the effect of each crop would help the stakeholders make a rational decision in choosing appropriate cropping patterns to avoid groundwater depletion as well as maintain their livelihoods. The Qazvin plain in Iran, whose aquifer has had a drawdown of nearly 20m during the last 15 years, was used in this case study. It has been modeled using system dynamics, which includes two subsystems: hydrology, for calculating groundwater level, and economy, for defining farmer’s income in the years from 1997 to 2011. The system dynamics, which included 17 crops, was developed after calibration by simple genetic algorithm and verification under extreme condition tests. To identify the economic and environmental effect of each of the crops, the system dynamics was run 18 times, removing crops one by one. It has been found that wheat plays an important role in causing a negative water balance but does not affect the farmers’ incomes as significantly as grapes. Two indicators, which included sustainable water resources and water exploitation, were employed to assess the scenarios as well. According to the results, no scenarios are fully sustainable for maintaining a steady aquifer, but scenario 1, which removed wheat from the cropping pattern, is the most sustainable and puts the least pressure on the aquifer.

Microbial mat contribution to the formation of an evaporitic environment in a temperate-latitude ecosystem

An evaporitic environment is characterized by having high salinity, climatic, and hydrological factors that promote a negative water balance; however, biological factors may also influence their development. Modern coastal flat Paso Seco (40°33′S; 62°14′W) is located in a semi-arid region with low precipitation and dry winds coming mainly from the NW. The site is an old tidal channel, which nowadays behaves like a shallow coastal saline-like basin, separated from the sea by a sand barrier, which the sea periodically overcomes, flooding the flat with eventual water evaporation. Microbial mats of up to 1 cm thick colonize the sandy sediments of this evaporitic environment. Water samples were taken during five field trips (2017–2018) from interstitial water of the flat, a tidal creek that crosses the flat, and two shallow tidal depressions (TDs) within the flat with different degrees of evaporation. In comparison to the sea, the maximum salinity values measured in Austral spring (September 2017) in the tidal creek were doubled, tripled in interstitial water, and 5.9 to 8 times higher in TDs. Ionic concentration denotes that evaporite chemical divides are followed as water evaporates, corresponding to the presence of CaCO3, gypsum and halite found in TDs. On-site permeability of microbial mat-covered surfaces presented semi-pervious properties. Microbial mat presence is condition for CaCO3, gypsum, and halite precipitation as they allow for water retention and its consequent evaporation due to the impermeability they confer to the sedimentary surface. Thus, microbial mats are a biological factor affecting the development of an evaporitic environment.

Effects of Drugs and Excipients on Hydration Status.

Despite being the most essential nutrient, water is commonly forgotten in the fields of pharmacy and nutrition. Hydration status is determined by water balance (the difference between water input and output). Hypohydration or negative water balance is affected by numerous factors, either internal (i.e., a lack of thirst sensation) or external (e.g., polypharmacy or chronic consumption of certain drugs). However, to date, research on the interaction between hydration status and drugs/excipients has been scarce. Drugs may trigger the appearance of hypohydration by means of the increase of water elimination through either diarrhea, urine or sweat; a decrease in thirst sensation or appetite; or the alteration of central thermoregulation. On the other hand, pharmaceutical excipients induce alterations in hydration status by decreasing the gastrointestinal transit time or increasing the gastrointestinal tract rate or intestinal permeability. In the present review, we evaluate studies that focus on the effects of drugs/excipients on hydration status. These studies support the aim of monitoring the hydration status in patients, mainly in those population segments with a higher risk, to avoid complications and associated pathologies, which are key axes in both pharmaceutical care and the field of nutrition.

Quantitative model-data comparison of mid-Holocene lake-level change in the central Rocky Mountains

Recently-developed Holocene lake-level reconstructions from the Rocky Mountains offer a quantitative target for testing the skill of state-of-the-art climate system models in simulating hydroclimate change. Here, we use a combination of hydrologic models of catchment streamflow, lake energy balance, and lake water balance to simulate lake level at Little Windy Hill Pond (LWH) in the Medicine Bow Range of Wyoming for a period of severe drought during the mid-Holocene (MH; approximately 6000 years ago). Using Coupled Model Intercomparison Project (CMIP5) output to drive our hydrologic models, we find that none of our simulations reproduce the significantly lowered lake levels at LWH during the MH. Rather, simulated hydroclimate changes for the MH are modest (< 10% reductions in precipitation and streamflow and generally 10–30% increases in lake evaporation), and LWH lake-level changes are buffered by the large volume of snowmelt runoff that the lake receives. Only when winter precipitation is approximately halved in sensitivity experiments do water inputs to the lake become small enough that lake level can be significantly drawn down by year-over-year negative water balances. Possible explanations for the model-data mismatch could lie in the realism of our hydrological modeling framework or in the accuracy of the CMIP5 output, the latter having important implications for projections of future drying in western North America.

On the Problem of Gypsum Deposition in the Dead Sea in the Case of Two Seas Canal Construction

The Dead Sea is a terminal lake, being the lowest and one of the most saline lakes on earth. For more than last fifty years the water level of the Dead Sea drastically decreased resulting in a drop of more than 30 m since beginning of sixties of the last century. The present level and size of the Dead Sea and its development are determined by a negative water balance between precipitation, runoff and evaporation. One of the possible ways to stop reducing the surface level of the Dead See and even to reverse this process, it is to supply seawater by connecting the Dead Sea with a world ocean system. The first and the most suitable choice discussed from the seventies of the last century was a canal connecting the Dead Sea with the Mediterranean Sea. However, due to geopolitical situation in this region the project of Dead Sea - Mediterranean Sea canal was abandoned, and another two seas canal variant has been studying for the last several decades, namely a canal between the Dead Sea and the Rea Sea via the Gulf of Eilat/Aqaba. The problems attracting the wide public attention for this canal construction are the ecological effects of mixing the waters of the Dead Sea and seawater from the Red Sea if the canal between these two seas will be built. There are some fears that under certain conditions, a layer of gypsum crystals floating on the Dead Sea surface will be formed causing some undesirable ecological effects in local environment. In the present article the rates of the deposition of gypsum crystals in the mixtures of the Dead Sea water with seawater were estimated by using the experimental viscosity and density values of these waters mixtures. The results of these calculations allowed us to assume that there is no danger that gypsum crystals, which can be formed under certain conditions during mixing of Dead Sea and seawater, will float on the Dead Sea water surface forever and after a relatively short period of time, depending on the dimensions of the crystals, gypsum crystals will sink to the bottom.

Quantitative analysis of water balance components in Lake Urmia, Iran using remote sensing technology

Accurate quantification of water balance components in large lakes is of great importance in assessing the changes in hydrological components, and subsequent variations in lakes water balance. The water balance of Urmia Lake in northwestern Iran was quantitatively analyzed in the year 2005 using remotely-sensed data (e.g. evapotranspiration and precipitation) and meteorological data. The analysis was based on GIS operations. For this purpose, the estimation of pixel-scaled monthly evapotranspiration (ET) was conducted via the Surface Energy Balance Algorithm for Land (SEBAL) using time series of Moderate Resolution Imaging Spectroradiometer (MODIS) images and meteorological data; precipitation was derived from the monthly Tropical Rainfall Measuring Mission (TRMM) satellite observations; surface runoff was estimated by the empirical formula; and finally, the computations of recharge were carried out using the water balance approach for the winter months where estimation of ET and surface runoff were subtracted from precipitation. Water balance components were quantified for the lake and the lake basin separately. Results showed that the water balance components calculated by remote sensing were in conformity with the reported figures in the literature. According to the results of the water balance method, Urmia Lake was suffering from a negative water balance of 3443 MCM yr−1. Findings of this study demonstrated the application of the derived satellite data in estimating lake's water balance components in order to improve the accuracy of the lake water budget calculation.

Climate Change and Future Wildfire in the Western United States: An Ecological Approach to Nonstationarity

AbstractWe developed ecologically based climate‐fire projections for the western United States. Using a finer ecological classification and fire‐relevant climate predictors, we created statistical models linking climate and wildfire area burned for ecosections, which are geographic delineations based on biophysical variables. The results indicate a gradient from purely fuel‐limited (antecedent positive water balance anomalies or negative energy balance anomalies) to purely flammability‐limited (negative water balance anomalies or positive energy balance anomalies) fire regimes across ecosections. Although there are other influences (such as human ignitions and management) on fire occurrence and area burned, seasonal climate significantly explains interannual fire area burned. Differences in the role of climate across ecosections are not random, and the relative dominance of climate predictors allows objective classification of ecosection climate‐fire relationships. Expected future trends in area burned range from massive increases, primarily in flammability limited systems near the middle of the water balance deficit distribution, to substantial decreases, in fuel‐limited nonforested systems. We predict increasing area burned in most flammability‐limited systems but predict decreasing area burned in primarily fuel‐limited systems with a flammability‐limited (“hybrid”) component. Compared to 2030–2059 (2040s), projected area burned for 2070–2099 (2080s) increases much more in the flammability and flammability‐dominated hybrid systems than those with equal control and continues to decrease in fuel‐limited hybrid systems. Exceedance probabilities for historical 95th percentile fire years are larger in exclusively flammability‐limited ecosections than in those with fuel controls. Filtering the projected results using a fire‐rotation constraint minimizes overprojection due to static vegetation assumptions, making projections more conservative.

Adaptation Strategies of the Hydrosocial Cycles in the Mediterranean Region

The Spanish Mediterranean region has been affected by several factors over the years (climatic conditions of aridity, high water demands, rapid and intense urban and population growth, climate change), that have generated a negative water balance whereby water resources are unable to meet the demand. Diversifying supply sources by resorting to new resources has been a necessity that has stimulated the expansion and integration of non-conventional water sources (desalination and reuse of reclaimed water) and sustainable solutions. The aim of this paper is to evaluate the adaptation strategies that have been developed in Alicante, Benidorm and Torrevieja in order to adjust their hydrosocial cycles to development and future scenarios. The theoretical analysis developed in this paper is corroborated by the study of the hydrosocial cycle evolution of three cities in the southeast of Spain, and the adaptive measures that the different stakeholders involved in the cycle have developed in each of them. The input and output of the systems are accounted for with information provided by the management companies in each of the phases (urban consumption; treated, reused and desalinated volumes), which highlight how the diversification of resources and the incorporation of non-conventional resources have been essential for adaptation.

Pelagic Sea Snakes Drink Fresh Water at Beginning of Wet Season

The Yellow‐bellied sea snake (Hydrophis platurus) is the only pelagic species of marine snake and ranges from southern Africa across the Indo‐Pacific to the Pacific coast of Central America. It is subject to long‐range movements by drifting with gyres and currents, and it is the only species of sea snake to have reached the Americas. Like other sea snakes investigated recently, this species is dependent on fresh water (FW) and dehydrates at sea during periods of drought. Because of its pelagic marine habitat, the only source of FW for this snake is rainfall that forms a freshwater or dilute brackish‐water lens during intense precipitation over the ocean. In the coastal region of Guanacaste, Costa Rica, there is a 6‐mo dry season without significant rainfall usually ending in May. During a research trip to Costa Rica from 5 to 14 May 2017, we captured H. platurus daily during the morning and returned them immediately to the laboratory where they were air‐dried, weighed, and placed individually in FW. Snakes were held in FW for approximately 20 h, following which they were air‐dried on a towel and reweighed. Drinking of FW was observed immediately when some snakes were placed in FW; others were determined to have ingested water by changes in mass that occurred overnight (5 to 27 % body mass; mean = 14.2 ± 0.87 s.e.m.). When we arrived in Costa Rica, there had not been significant rainfall at the location where snakes were studied; the weather was hot and dry, and there was no precipitation over the ocean. A large proportion of snakes that were captured during the first two days drank FW. Between the second and third day there was heavy rainfall during the afternoon, and we observed that rain fell in large amounts over the Golfo de Papagayo where we collected the snakes. During the next several days, heavy rainfall occurred during the afternoon or evening, and precipitation again fell over the ocean. The percentage of snakes drinking after capture decreased with time, falling from ~ 80% before the rains began to 13% on the seventh day. Our data clearly indicate that fewer and fewer snakes were in negative water balance as the wet season began in context of precipitation we observed over the ocean. Thus, it is appropriate to conclude that thirsty snakes having accumulated a water deficit during the previous dry season were drinking from FW‐brackish oceanic lenses when precipitation began to fall over the Golfo de Papagayo. We were extremely fortunate to be able to quantify drinking behaviors of sea snakes precisely at the transition from dry to wet season when rainfall first impacted the ocean at our location. These data reinforce the importance of fresh water for pelagic sea snakes, which dehydrate in the ocean and are thus susceptible to changing patterns of precipitation that might result from climatic changes related to global warming.Support or Funding InformationNational Science Foundation grant IOS‐0926802 to HBLThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Rhodobacter sp. Rb3, an aerobic anoxygenic phototroph which thrives in the polyextreme ecosystem of the Salar de Huasco, in the Chilean Altiplano.

The Salar de Huasco is an evaporitic basin located in the Chilean Altiplano, which presents extreme environmental conditions for life, i.e. high altitude (3800m.a.s.l.), negative water balance, a wide salinity range, high daily temperature changes and the occurrence of the highest registered solar radiation on the planet (> 1200Wm-2). This ecosystem is considered as a natural laboratory to understand different adaptations of microorganisms to extreme conditions. Rhodobacter, an anoxygenic aerobic phototrophic bacterial genus, represents one of the most abundant groups reported based on taxonomic diversity surveys in this ecosystem. The bacterial mat isolate Rhodobacter sp. strain Rb3 was used to study adaptation mechanisms to stress-inducing factors potentially explaining its success in a polyextreme ecosystem. We found that the Rhodobacter sp. Rb3 genome was characterized by a high abundance of genes involved in stress tolerance and adaptation strategies, among which DNA repair and oxidative stress were the most conspicuous. Moreover, many other molecular mechanisms associated with oxidative stress, photooxidation and antioxidants; DNA repair and protection; motility, chemotaxis and biofilm synthesis; osmotic stress, metal, metalloid and toxic anions resistance; antimicrobial resistance and multidrug pumps; sporulation; cold shock and heat shock stress; mobile genetic elements and toxin-antitoxin system were detected and identified as potential survival mechanism features in Rhodobacter sp. Rb3. In total, these results reveal a wide set of strategies used by the isolate to adapt and thrive under environmental stress conditions as a model of polyextreme environmental resistome.

Groundwater uptake of different surface cover and its consequences in great Hungarian plain

IntroductionForest cover in Hungary has increased from 1.1 to 2.0 million hectares during the last century. The EU (European Union) promotes further afforestation; thus, 15,000–18,000 ha are being forested each year, mainly in the Hungarian Great Plain. In terms of species used for afforestation, poplar plantations are preferred over native oak woodlands.The groundwater uptake of trees can be a significant water balance element of forested areas in shallow groundwater environments within the Hungarian Great Plain. Forests can cause water table depressions and subsurface salt accumulation in areas with negative water balance. This study examined the hydrological impact of forest cover in the Hungarian Great Plain. Within the framework of this research, climatic water balance, water table depth and salinity, subsoil layering, tree species and stand age were analysed as influencing factors. This paper compares the effect which an oak forest, a poplar plantation and a pasture have on groundwater uptake and salt accumulation.ResultsThe water table level was roughly 0.4–0.5 m lower beneath the oak forest and the poplar plantation than it was beneath the pasture. Forest groundwater use was 1.5–2 times higher than that of grassland. Groundwater uptake of oak forest was greater than that of poplar plantation during the monitoring period. Salt accumulation, which shows water use in the longer run, was slightly higher for poplar in deeper layers.ConclusionsThe greater amount of groundwater used by trees does not lead to a higher salt uptake as only a slight accumulation of salt was measured beneath the forests. Overall, hybrid poplar was slightly less favourable than native oak when considering salinization effects. However, even greater groundwater uptake by trees over longer timescales could cause more significant salt accumulation under pronounced drought conditions due to climate change.

Heparin-Free Prolonged Intermittent Hemodialysis Using Calcium-Free Citrate Dialysate in Critically Ill Patients.

Critically ill patients who have a high risk of bleeding but require prolonged intermittent dialysis need a heparin-free easy-to-use alternative type of anticoagulation within the dialysis circuit. We assessed the safety and efficiency of heparin-free regional citrate anticoagulation of the dialysis circuit using a calcium-free citrate-containing dialysate, with calcium reinjected according to ionic dialysance. Prospective cohort study. Critical care units. Critically ill patients who required renal replacement therapy. None. A total of 101 dialysis sessions were performed in 35 patients (mechanical ventilation n = 78; norepinephrine n = 13). Median duration of dialysis was 294 minutes (interquartile range, 240-300), and median ultrafiltration volume was 2.3 L (1-2.8). Urea and β2-microglobulin reduction rates were 64.5% ± 0.4% and 48% ± 0.13%, respectively. Postfilter ionized calcium was 0.35 ± 0.17 and 0.38 ± 0.14 mmol/L at 1 and 3 hours, respectively, within the extracorporeal circuit. A major clotting event that led to premature termination of the session occurred in only three of 101 sessions. In these three cases, major catheter dysfunction occurred before clotting within the circuit. Prefilter ionized calcium remained within narrow ranges (before/after change +0.07 ± 0.006 mmol/L), and total-to-ionized calcium ratio, a surrogate marker for citratemia, was unchanged. Dialysis anticoagulation with calcium-free citrate-containing dialysate and calcium reinjection according to ionic dialysance is an easy-to-use, efficient, and inexpensive form of heparin-free regional anticoagulation. It allows prolonged hemodialysis sessions in critically ill patients without the need to systemically monitor ionized calcium. Furthermore, sessions can be safely extended according to the hemodynamic tolerance to ensure an adequate dose of dialysis and a negative water balance, a major point in patients with severe acute kidney disease.

Combined preharvest and postharvest treatments affect rapid leaf wilting in Bouvardia cut flowers

Bouvardia is an ornamental shrub, commercially cultivated as flowering stem. Occasionally, negative water balance, which leads to rapid leaf wilting, ends vase life immediately. This work studies the effect of preharvest and postharvest conditions on vase life, water uptake and transpiration. Stems grown at moderate RH show a significantly longer vase life, lower water uptake and transpiration rate compared to those grown at high RH. Postharvest treatments overcoming air emboli and wound response had a positive effect on vase life. One of the treatments to overcome air emboli, surfactant treatment, increased water uptake and transpiration rate compared to control. Higher water deficit was measured in stems that had reduced vase life. Stomata malfunction (not closing in response to closing stimuli) resulting from high air humidity during growth conditions is likely one cause for the negative water balance. A combination of high transpiration rate (due to high RH) and hindering of vase water uptake (due to air emboli and/or stem-wounding responses) is likely the main reason for early wilting of Bouvardia leaves and short vase life.