Search

Sanmen Bay (SMB) is one of the important harbors in Zhejiang Province. It is a semi-enclosed shallow bay that has undergone large-scale land reclamation activities. Long-term reclamation has changed the hydrodynamic conditions of SMB, such as tide, residual current, tidal prism, water exchange capacity, and tidal asymmetry. In this study, three typical periods of numerical models, based on historical charts and remote sensing, were established to investigate the influence of reclamation activities on the hydrodynamic conditions of SMB from 1971 to 2020. These model results reveal that the amplitude and phase of M2, the main tidal components in SMB, decreased by ~0.1-0.3 m and ~ 5°-15°, respectively, over the last half-century. Additionally, under the influence of ~200 km2 reclamation, many hydrodynamic conditions in SMB also changed. This includes the reduction of a residual current and tidal prism, an increase in residence time, and a change in tidal asymmetry characteristics. The residence time in nearby Xiayangtu exhibited a downward trend from 2003 to 2020, because land reclamation squeezed, and thus, enhanced the residual current eddy. The water-exchange capacity of the bay became weaker with the reduction of tidal prism to one-third and an increase in residence time. The tidal asymmetry characteristic of SMB changed from half of flood dominant to fully flood dominant by the influence of shoreline and bathymetry, which raised the flood risk. Research on the response of the hydrodynamic environment to reclamation activities in SMB reminds the local government to reassess the impact of land reclamation on the hydrodynamic environment. [ABSTRACT FROM AUTHOR]

The Baltic Sea is currently classified as 'affected by eutrophication'. In this study, water exchanges and net phosphorus flows in the Archipelago Sea and through the Åland Sea from the Baltic proper was estimated with the aid of a 3-D hydrodynamic model for the years 2000–2021. The modelling configuration is based on the Copernicus regional reanalysis data. W ater flowed from the Baltic proper to the Bothnian Sea at 669 km3/a and out from there at 879 km3/a. The inflow occurred in the deep-water layer (over 40 m), while the outflow occurred in the surface layer (0–40 m). With the inflow, 14,500 tons/a of phosphorus were transported during the years 2000–2014, but the amount increased to 20,300 tons per year from 2015 to 2021. At the same time, the winter-time concentrations of DIP in the Bothnian Sea almost doubled.   In the Archipelago Sea, the main flow direction of water was from south to north from 2000 to 2014. From 2015 to 2021, the net flow direction reversed, and water flowed from the Archipelago Sea to the Baltic proper in the surface layer at a rate of 140 km3/a. At the same time, the background loading of phosphorus entering the Archipelago Sea with the flows decreased significantly and the chlorophyll-a concentration decreased below the threshold for a good ecological status.   The U-turn in surface currents in the Archipelago Sea since 2015 may be related to variations in upwellings caused by climate change. [ABSTRACT FROM AUTHOR]

The blood–brain barrier (BBB) is a barrier protecting the brain and a milieu of continuous exchanges between blood and brain. There is emerging evidence that the BBB plays a major role in epileptogenesis and drug‐resistant epilepsy, through several mechanisms, such as water homeostasis dysregulation, overexpression of drug transporters, and inflammation. Studies have shown abnormal water homeostasis in epileptic tissue and altered aquaporin‐4 water channel expression in animal epilepsy models. This review focuses on abnormal water exchange in epilepsy and describes recent non‐invasive MRI methods of quantifying water exchange. Plain Language Summary: Abnormal exchange between blood and brain contribute to seizures and epilepsy. The authors describe why correct water balance is necessary for healthy brain functioning and how it is impacted in epilepsy. This review also presents recent MRI methods to measure water exchange in human brain. These measures would improve our understanding of factors leading to seizures. [ABSTRACT FROM AUTHOR]

Abstract The blood–brain barrier (BBB) is a barrier protecting the brain and a milieu of continuous exchanges between blood and brain. There is emerging evidence that the BBB plays a major role in epileptogenesis and drug‐resistant epilepsy, through several mechanisms, such as water homeostasis dysregulation, overexpression of drug transporters, and inflammation. Studies have shown abnormal water homeostasis in epileptic tissue and altered aquaporin‐4 water channel expression in animal epilepsy models. This review focuses on abnormal water exchange in epilepsy and describes recent non‐invasive MRI methods of quantifying water exchange. Plain Language Summary Abnormal exchange between blood and brain contribute to seizures and epilepsy. The authors describe why correct water balance is necessary for healthy brain functioning and how it is impacted in epilepsy. This review also presents recent MRI methods to measure water exchange in human brain. These measures would improve our understanding of factors leading to seizures.

Atmospheric frontal passage is a common meteorological event that can significantly affect hydrodynamics in coastal environments, including the hydrological connectivity between channels and floodplains that regulates material transport in river deltas. This study is focused on the influence of atmospheric cold fronts on the hydrological connectivity between channels and floodplains within the Wax Lake Delta using the Delft3D FM model. The results demonstrate a substantial effect of passing cold fronts on the exchange of water and transport fraction between the primary channels and floodplains. This impact is intricately connected to the morphodynamical characteristics of the floodplains, the intensity of cold fronts, river discharge, Coriolis force, and tidal currents. The passing cold fronts can enhance or reverse the direction of water exchange between channels and floodplains. For floodplains, the passage of cold fronts can lead to an increase in the rate of water exchange by as much as five times. In the WLD, a substantial fraction of water, 39-58%, is flowing through the floodplains to the bay at the delta front influenced by the prevailing discharge, although there is a significant spatial heterogeneity. Passing cold fronts can alter the transport distribution, depending on the phase of the front. An increase in river discharge tends to bolster floodplain connectivity and lessen the effects of cold fronts. Conversely, decreased river discharge results in reduced connectivity and exacerbates the fluctuations induced by cold fronts. Moreover, the findings indicate that from the apex to downstream, the contribution of channels decreases as they become shallower, while the role of the floodplains increases, leading to a less distinct demarcation between channels and floodplains. It has also been noted that an increase in river discharge correlates with an increased contribution from floodplains to transfer water to the bay. [ABSTRACT FROM AUTHOR]

Study region: Dongting Lake Basin of China. Study focus: Dongting Lake is the first large-scale interconnected river–lake systems in the middle-lower reaches of the Yangtze River and the second-largest freshwater lake in China. Dam operation on the upper reaches of the Yangtze River dramatically affected the hydrological condition of Dongting Lake. Therefore, this study established a hydrodynamic-water age model to assess the effects of the Three Gorges Dam (TGD) on the spatiotemporal pattern of water age in Dongting Lake. New hydrological insights: The results show a significant spatial and temporal variation of water age in Dongting Lake. Water age in the floodway is lower than that in the shoal, meanwhile, water age in spring and summer is lower than that in autumn and winter. By establishing a hydrodynamic-water age model, several factors influencing water age in Dongting Lake were analyzed, i.e., the influences of the Jingjiang Three Outlets' triage from the Yangtze River, the water level of the mainstream of the Yangtze River, and the flow pattern. The TGD could influence the water age in Dongting Lake by altering the hydrodynamic conditions of the Yangtze River. Results from this study provide support for flood control and dispatch management of Dongting Lake and provides a reference for water exchange studies in other large shallow lakes.

Macrochloa tenacissima (M. tenacissima), or esparto, is a perennial tussock grass that coexists with Pinus halepensis (P. halepensis) in semi-arid Mediterranean woodlands. This research was carried out to explore diurnal transpiration at leaf level in esparto grass under different levels of pine–esparto competition and in contrasting environmental soil water conditions. The measurement period spanned from the summer of 2020 to the spring of 2021. The relationship between transpiration and competition was conducted in open and closed P. halepensis stands, and the type of leaf (green, senescent) and the maturity of the esparto grass were taken into account. We observed a higher control of transpiration in green leaves, and the correlations between the transpiration and pine competition were noted exclusively in this type of leaf. Our results demonstrated a significant impact of pine competitors (closed stands) on the transpiration of esparto grass, particularly during seasons characterized by scenarios of high water demand: the summer drought period and the commencement of the growing and flowering period (spring). Furthermore, our findings revealed a greater response to transpiration in mature bushes compared to young ones under severe water stress, indicating a higher adaptation to drought by esparto as it ages. Although our results confirmed that PAR increased transpiration in all seasons and in both stands, which is attributable to the heliophilia of esparto grass, the site effects on transpiration could also be attributable to competition for water, especially during periods of drought. These results may have important implications for the dynamics and management of these semi-arid mixed woodlands, as well as the planning of reforestation programs aimed at restoring esparto grass formations. [ABSTRACT FROM AUTHOR]

Atmospheric frontal passage is a common meteorological event that can significantly affect hydrodynamics in coastal environments, including the hydrological connectivity between channels and floodplains that regulates material transport in river deltas. This study is focused on the influence of atmospheric cold fronts on the hydrological connectivity between channels and floodplains within the Wax Lake Delta using the Delft3D FM model. The results demonstrate a substantial effect of passing cold fronts on the exchange of water and transport fraction between the primary channels and floodplains. This impact is intricately connected to the morphodynamical characteristics of the floodplains, the intensity of cold fronts, river discharge, Coriolis force, and tidal currents. The passing cold fronts can enhance or reverse the direction of water exchange between channels and floodplains. For floodplains, the passage of cold fronts can lead to an increase in the rate of water exchange by as much as five times. In the WLD, a substantial fraction of water, 39-58%, is flowing through the floodplains to the bay at the delta front influenced by the prevailing discharge, although there is a significant spatial heterogeneity. Passing cold fronts can alter the transport distribution, depending on the phase of the front. An increase in river discharge tends to bolster floodplain connectivity and lessen the effects of cold fronts. Conversely, decreased river discharge results in reduced connectivity and exacerbates the fluctuations induced by cold fronts. Moreover, the findings indicate that from the apex to downstream, the contribution of channels decreases as they become shallower, while the role of the floodplains increases, leading to a less distinct demarcation between channels and floodplains. It has also been noted that an increase in river discharge correlates with an increased contribution from floodplains to transfer water to the bay.

Background: Recently, the ENDOANGEL (EN) system, a computer-assisted detection technique, and water exchange (WE) assisted colonoscopy have both been shown to increase the colorectal adenoma detection rate (ADR). Objectives: The aim of this study was to compare the ADR between EN- and WE-assisted colonoscopy. Design: This was a retrospective study. Methods: Data from patients who underwent either EN- or WE-assisted colonoscopy between October 2021 and August 2022 were analysed consecutively. The primary outcome measure was the ADR. Results: The ADR was found to be similar between the EN and WE groups, with 80 out of 199 (40.2%) patients in the EN group compared to 78 out of 174 (44.8%) patients in the WE group [1.21; 95% confidence interval (CI), 0.80–1.83]. In the analysis using stabilized inverse probability treatment weighting after adjustment for confounding factors, both colonoscopy methods had similar performance in terms of ADR (1.41; 95% CI, 0.88–2.27). Conclusion: EN was found to be comparable to WE in terms of ADR during colonoscopy, and both methods may be effectively used in clinical practice. [ABSTRACT FROM AUTHOR]

The self-purification capacity of semi-closed bays is closely related to the exchange process of open sea water. In recent years, with the enhancement of human development activities, environmental problems such as eutrophication, weak hydrodynamics, and poor water exchange capacity have appeared in the bays. In this paper, the water exchange time and flow field in Jiaozhou Bay (JZB) were investigated using the environmental fluid dynamics code with a coupled dye module. Specifically, Jiaozhou Bay was divided into seven zones to explore the effect mechanism of a monsoon on the water exchange process. A detailed analysis was performed on the current water exchange status in the highly polluted northeastern region of the bay and its influence on the surrounding areas. Based on the definition of the average residence time and considering the effect of the tracer release moment, the distribution of the water exchange time in the bay under three circumstances was obtained. Results showed that the timing of the tracer release exerted minimal influence on the average residence time. The water exchange process was influenced by a combination of astronomical and meteorological factors. The overall exchange capacity of the bay was strongest under the impact of a winter monsoon and tides, followed by a summer monsoon and tides, and the weakest exchange occurred under the influence of tides alone. Moreover, both summer and winter monsoons greatly facilitated water exchange in the heavily polluted northeastern region. However, pollutants from this region had a significant impact on surrounding areas during a summer monsoon. Changes in the structure and intensity of residual flow fields were the primary causes of exchange rate discrepancies. [ABSTRACT FROM AUTHOR]

Purpose. The paper is purposed at studying the dynamics and reasons of the Black Sea water inflows to the Sea of Azov, as well as the features of their seasonal variability. Methods and Results. Medium and high resolution satellite data, and also the results of numerical modeling the salinity field of the Azov-Black Sea basin for 2008-2009 by the high resolution (1 km) NEMO model were used. The analysis showed that the transparent and salty Black Sea waters were recorded most frequently in the southern and southeastern parts of the Azov Sea during a cold season. Based on the satellite measurements, the maximum number of inflows was observed in November and March, and the minimum one – from June to October. Similar results were obtained from the data of numerical calculations for 2008-2009: in winter, intense salt water inflows to the Sea of Azov (the flow exceeds 20 tons/s) are observed in a third of cases, and in some cases, the estimated salt flux attains 60 tons/s, whereas in summer their number is close to zero. Further the Black Sea waters move predominantly in a cyclonic direction, sometimes reaching the basin center. In some cases, high density gradients induce the development of an intense cyclonic eddy near the strait at the front of the Black Sea water inflows. The simulation data made it possible to assess the relationship between the wind and the salt fluxes to the Sea of Azov. It is shown that this relationship is of a cubic nature that is partly explained by increase of the inflowing water salinity caused by the intensified vertical mixing during the storms. Conclusions. The main hydrodynamic reasons for the Black Sea water inflows to the Sea of Azov and their seasonal variability are the following: 1) intense wind transfer during the south winds; 2) frontal currents at the boundary of upwellings near the Kerch Peninsula during the western and southwestern winds; 3) orbital currents of the passing anticyclones which are able to induce a northerly water transport in the strait at any wind conditions.

Water exchange between the different compartments of a heterogeneous specimen can be characterized via diffusion magnetic resonance imaging (dMRI). Many analysis frameworks using dMRI data have been proposed to describe exchange, often using a double diffusion encoding (DDE) stimulated echo sequence. Techniques such as diffusion exchange weighted imaging (DEWI) and the filter exchange and rapid exchange models, use a specific subset of the full space DDE signal. In this work, a general representation of the DDE signal was employed with different sampling schemes (namely constant b1, diagonal and anti-diagonal) from the data reduction models to estimate exchange. A near-uniform sampling scheme was proposed and compared with the other sampling schemes. The filter exchange and rapid exchange models were also applied to estimate exchange with their own subsampling schemes. These subsampling schemes and models were compared on both simulated data and experimental data acquired with a benchtop MR scanner. In synthetic data, the diagonal and near-uniform sampling schemes performed the best due to the consistency of their estimates with the ground truth. In experimental data, the shifted diagonal and near-uniform sampling schemes outperformed the others, yielding the most consistent estimates with the full space estimation. The results suggest the feasibility of measuring exchange using a general representation of the DDE signal along with variable sampling schemes. In future studies, algorithms could be further developed for the optimization of sampling schemes, as well as incorporating additional properties, such as geometry and diffusion anisotropy, into exchange frameworks.

The Baltic Sea is currently classified as ‘affected by eutrophication’. In this study, water exchanges and net phosphorus flows in the Archipelago Sea and through the Åland Sea from the Baltic proper was estimated with the aid of a 3-D hydrodynamic model for the years 2000–2021. The modelling configuration is based on the Copernicus regional reanalysis data. Water flowed from the Baltic proper to the Bothnian Sea at 669 km3/a and out from there at 879 km3/a. The inflow occurred in the deep-water layer (over 40 m), while the outflow occurred in the surface layer (0–40 m). With the inflow, 14,500 tons/a of phosphorus were transported during the years 2000–2014, but the amount increased to 20,300 tons per year from 2015 to 2021. At the same time, the winter-time concentrations of DIP in the Bothnian Sea almost doubled. In the Archipelago Sea, the main flow direction of water was from south to north from 2000 to 2014. From 2015 to 2021, the net flow direction reversed, and water flowed from the Archipelago Sea to the Baltic proper in the surface layer at a rate of 140 km3/a. At the same time, the background loading of phosphorus entering the Archipelago Sea with the flows decreased significantly and the chlorophyll-a concentration decreased below the threshold for a good ecological status. The U-turn in surface currents in the Archipelago Sea since 2015 may be related to variations in upwellings caused by climate change.

The Neva Bay is a body of water located between the delta of the Neva River and Kotlin Island. The goal of the study was to develop a method for numerical modeling of the shallow water equation in the Neva Bay, based on the finite element method. To achieve this goal, we solved a number of tasks. First, we selected characteristic periods in the history of the Neva Bay and formed numerical modeling options while determining boundary conditions. Secondly, we determined the geometric characteristics of the computational domain for modeling options and formed a finite element mesh for each of the options. Then, we found a numerical solution of hydrodynamic problems in terms of determining values of current velocity vectors. Finally, we conducted a comparative analysis of the results of solving the hydrodynamic problem of the structure of currents in the Neva Bay in different periods of history. The changes in the velocity field occurred because of the construction of the fairway and the dams for the Complex of flood protection structures (CFPS) in St. Petersburg. Today there is practically no water flow south of the Sea Canal. Water exchange between the Neva Bay and the Gulf of Finland is carried out due to culvert structures in the northern part of the CFPS and navigation facilities. The average flow of the Neva River during the calculation period did not change and was about 2500 m3/s (depends on the water level in Lake Ladoga); an increase in speeds occurs north of the Sea Canal.

Water exchange between the different compartments of a heterogeneous specimen can be characterized via diffusion magnetic resonance imaging (dMRI). Many analysis frameworks using dMRI data have been proposed to describe exchange, often using a double diffusion encoding (DDE) stimulated echo sequence. Techniques such as diffusion exchange weighted imaging (DEWI) and the filter exchange and rapid exchange models, use a specific subset of the full space DDE signal. In this work, a general representation of the DDE signal was employed with different sampling schemes (namely constant b1, diagonal and anti-diagonal) from the data reduction models to estimate exchange. A near-uniform sampling scheme was proposed and compared with the other sampling schemes. The filter exchange and rapid exchange models were also applied to estimate exchange with their own subsampling schemes. These subsampling schemes and models were compared on both simulated data and experimental data acquired with a benchtop MR scanner. In synthetic data, the diagonal and near-uniform sampling schemes performed the best due to the consistency of their estimates with the ground truth. In experimental data, the shifted diagonal and near-uniform sampling schemes outperformed the others, yielding the most consistent estimates with the full space estimation. The results suggest the feasibility of measuring exchange using a general representation of the DDE signal along with variable sampling schemes. In future studies, algorithms could be further developed for the optimization of sampling schemes, as well as incorporating additional properties, such as geometry and diffusion anisotropy, into exchange frameworks. [ABSTRACT FROM AUTHOR]

Purpose. The work is purposed at studying the synoptic variability of hydrophysical parameters in the basins of the Azov and Black seas induced by the water masses inflow through the strait; at that the inflowing water features differ from the analogous ones in the above-noted basins. Methods and Results. The results of numerical modeling of circulation in the cascade of seas (the Azov – Black – Marmara seas) for 2008–2009 were analyzed. Regional configuration of the NEMO numerical modeling platform and the results of the ERA5 atmospheric reanalysis were used. The main results were obtained for the configuration with the ~ 1.1 km spatial resolution of the computational grid. The processes of the Azov Sea waters inflow to the Black Sea and their further evolution, as well as the analogous processes with Black Sea waters in the Azov Sea basin are demonstrated. The estimates of water and salt exchange through the Kerch Strait are represented. Conclusions. Regular change of the water transfer direction through the strait conditioned by the wind significant variability constitutes the basic mechanism for the changes in water exchange between the basins. Having being analyzed, the events with the exceeding average annual values in the unidirectional salt flows through the Kerch Strait permitted to identify significant salt inflows to the Sea of Azov. The portion of such events ranges from 20–25 to almost 70 % of the total number of inflows.

Fissures and conduits are main void of karstic aquifer. Karst aquifers are highly vulnerable to contamination as water exchange between fissure system and conduit system greatly influences the karstification of limestone terrains, heterogeneity of karstic aquifer, and spring flow regime. A two-dimensional tank model was constructed, and a corresponding numerical model (MODFLOW-2005 Conduit Flow Process Mode 1, CFPM1) was developed to explore the effects of rainfall intensity and intrinsic structure of karst system (hydraulic conductivity of fissures and conduit diameter) on conduit-matrix water exchange. Nine different scenarios were designed to quantitatively simulate the spatial and temporal variability of water exchange between the fissures and conduits. The study reproduced the area of fissure water recharging to conduit (recharge zone), the area of conduit water discharging to fissure water (discharge zone) and the area of fissure water moving laterally (transport zone) in both physical model and numerical model. The results from rainfall scenarios show a relatively stable ratio of exchange zone (recharge zone and discharge zone) with increasing rainfall intensity, indicating that conduit-matrix water exchange is not sensitive to rainfall intensity, and conduit water discharging to fissure water is just a short-term phenomenon. It is also found that an increase in hydraulic conductivity of fissure system enhances extensiveness of water transport, but restrains conduit-matrix water exchange. However, the enlargement of conduit can prompt the extent of conduit-matrix water exchange. A positive feedback between the extent of conduit-matrix water exchanges and karstification can be confirmed. These findings might be essential for better understanding groundwater flow dynamics in karst aquifers.

Macrochloa tenacissima (M. tenacissima), or esparto, is a perennial tussock grass that coexists with Pinus halepensis (P. halepensis) in semi-arid Mediterranean woodlands. This research was carried out to explore diurnal transpiration at leaf level in esparto grass under different levels of pine–esparto competition and in contrasting environmental soil water conditions. The measurement period spanned from the summer of 2020 to the spring of 2021. The relationship between transpiration and competition was conducted in open and closed P. halepensis stands, and the type of leaf (green, senescent) and the maturity of the esparto grass were taken into account. We observed a higher control of transpiration in green leaves, and the correlations between the transpiration and pine competition were noted exclusively in this type of leaf. Our results demonstrated a significant impact of pine competitors (closed stands) on the transpiration of esparto grass, particularly during seasons characterized by scenarios of high water demand: the summer drought period and the commencement of the growing and flowering period (spring). Furthermore, our findings revealed a greater response to transpiration in mature bushes compared to young ones under severe water stress, indicating a higher adaptation to drought by esparto as it ages. Although our results confirmed that PAR increased transpiration in all seasons and in both stands, which is attributable to the heliophilia of esparto grass, the site effects on transpiration could also be attributable to competition for water, especially during periods of drought. These results may have important implications for the dynamics and management of these semi-arid mixed woodlands, as well as the planning of reforestation programs aimed at restoring esparto grass formations.

Gangnan Reservoir is an important water source of Shijiazhuang, the seat of northern China’s Hebei Province. The irregular shape of the reservoir makes it easy for water to stop flowing in bays, forming dead water areas. Serious water quality problems will ensue. To disclose the influence of a water diversion project on the water exchange in Gangnan Reservoir, this paper sets up a hydrodynamic and water exchange model for the reservoir based on the convection–diffusion theory. According to different diversion flows and wind fields, a total of 12 working conditions was configured to numerically simulate the water exchange in the reservoir. The results show that: the diversion flow is the main factor affecting the water exchange rate. In the main reservoir areas, the water exchange rate increases gradually, finally, it can reach a relatively high level. In the bay areas, the water exchange rate is relatively small, and affected by the diversion flow and the bay location. The wind field has different impacts on the water exchange rate in the main reservoir areas and the bay areas. The impact is small in the former areas, yet significant in the latter areas. When it is not windy, the residence time decreases with the increase of the flow. When it is windy, the wind field of each direction shortened the residence time in the bay areas, while increased that in the main reservoir areas. Furthermore, the transport and diffusion law of water pollutants in Gangnan Reservoir was analyzed by the connectivity matrix: When the main reservoir areas are polluted, the pollutants greatly affect the main reservoir areas; When the bay areas are polluted, the pollutants only affect some adjacent water bodies. The research findings provide scientific reference for the diversion operation of Gangnan Reservoir.

Eggs are a vulnerable stage because they are sensitive to thermal and hydric conditions and yet cannot behaviourally avoid stressful environments. A general mechanistic model of egg development in natural nests requires microclimatic predictions of temperature, humidity, radiation (if above ground) and water potential (if buried in soil) to be integrated with models of heat and water exchange of the egg and the metabolism of the developmental process. Although all the required pieces for such a model now exist, they have not been integrated into a general modelling framework.We developed such an integration using NicheMapR package for mechanistic niche modelling. Specifically, we took an existing general model of egg water exchange and connected it with the microclimate model in NicheMapR to simulate nest thermal and hydric environments, including the effects of soil water potential on liquid and vapour exchange and moisture‐mediated soil thermal conductivity on heat exchange. We then used the Dynamic Energy Budget model within the ectotherm model of NicheMapR as the mechanistic engine for the developmental process, allowing the explicit computation of the dynamics of metabolic heat production and all aspects of mass exchange.We illustrate the modelling framework using existing laboratory and field data on reptiles, insects, and birds. We show that it can capture laboratory observations of water exchange and metabolic heat production and how it can be used to map potential development and water uptake under natural conditions at the continental scale.The modelling framework can be used to interpret laboratory experiments and allows strong inferences to be made about the abiotic constraints on egg development in natural nests under past, present, and future environmental change. [ABSTRACT FROM AUTHOR]

BackgroundA low adenoma detection rate (ADR) increases risks of interval cancers (ICs). Proximal colon flat polyps, e.g. serrated lesions (SLs), are difficult to find. Missed proximal colon flat lesions likely contribute to IC.AimsWe compared chromoendoscopy with water exchange (CWE), water exchange (WE) and air insufflation (AI) in detecting adenomas in screening colonoscopy.MethodsAfter split-dose preparation, 480 veterans were randomized to AI, WE and CWE.ResultsPrimary outcome of proximal ADR (55.6% vs 53.4% vs 52.2%, respectively) were similar in all groups. Adenoma per colonoscopy (APC) and adenoma per positive colonoscopy (APPC) were comparable. Detection rate of proximal colon SLs was significantly higher for CWE and WE than AI (26.3%, 23.6% and 11.3%, respectively, p = 0.002). Limitations: single operator; SLs only surrogate markers of but not IC.ConclusionsWhen an endoscopist achieves high-quality AI examinations with overall ADR twice (61.6%) the recommended standard (30%), use of WE and CWE does not produce further improvement in proximal or overall ADR. Comparable APC and APPC confirm equivalent withdrawal inspection techniques. WE alone is sufficient to significantly improve detection of proximal SLs. The impact of increased detection of proximal SLs by WE on prevention of IC deserves to be studied. This study is registered at ClinicalTrial.gov (NCT#01607255).

Abstracts: Blood-brain barrier (BBB) impairment is an important pathophysiological process in Alzheimer's disease (AD) and a potential biomarker for early diagnosis of AD. However, most current neuroimaging methods assessing BBB function need the injection of exogenous contrast agents (or tracers), which limits the application of these methods in a large population. In this study, we aim to explore the feasibility of vascular water exchange MRI (VEXI), a diffusion-MRI-based method proposed to assess the BBB permeability to water molecules without using a contrast agent, in the detection of the BBB breakdown in AD. We tested VEXI on a 3T MRI scanner on three groups: AD patients (AD group), mild cognitive impairment (MCI) patients due to AD (MCI group), and the age-matched normal cognition subjects (NC group). Interestingly, we find that the apparent water exchange across the BBB (AXRBBB) measured by VEXI shows higher values in MCI compared with NC, and this higher AXRBBB happens specifically in the hippocampus. This increase in AXRBBB value gets larger and extends to more brain regions (medial orbital frontal cortex and thalamus) from MCI group to the AD group. Furthermore, we find that the AXRBBB values of these three regions is correlated significantly with the impairment of respective cognitive domains independent of age, sex and education. These results suggest VEXI is a promising method to assess the BBB breakdown in AD.

Background: Recently, the ENDOANGEL (EN) system, a computer-assisted detection technique, and water exchange (WE) assisted colonoscopy have both been shown to increase the colorectal adenoma detection rate (ADR). Objectives: The aim of this study was to compare the ADR between EN- and WE-assisted colonoscopy. Design: This was a retrospective study. Methods: Data from patients who underwent either EN- or WE-assisted colonoscopy between October 2021 and August 2022 were analysed consecutively. The primary outcome measure was the ADR. Results: The ADR was found to be similar between the EN and WE groups, with 80 out of 199 (40.2%) patients in the EN group compared to 78 out of 174 (44.8%) patients in the WE group [1.21; 95% confidence interval (CI), 0.80–1.83]. In the analysis using stabilized inverse probability treatment weighting after adjustment for confounding factors, both colonoscopy methods had similar performance in terms of ADR (1.41; 95% CI, 0.88–2.27). Conclusion: EN was found to be comparable to WE in terms of ADR during colonoscopy, and both methods may be effectively used in clinical practice. [ABSTRACT FROM AUTHOR]

Physical forcings affect water exchange in coral reef atolls. Characteristics of the consequent water exchange depend on the atoll morphology and the local atmospheric and hydrographic conditions. The pattern of water exchange at the Dongsha atoll under the influences of tides, wind, and waves was investigated by conducting realistic modeling and numerical experiments. The analyses suggest that the southwestern wind could enhance the inflow transports at the southern reef flat and the outflow transports at the northern reef flat/north channel. The northeastern wind induces an inversed pattern. Unlike the wind, the waves always strengthen the inflow transports at the reef flat, and the locations of strengthened transports depend on the incident directions of the waves. Wind and waves induce shorter hydrodynamic time scales than tides, suggesting more vigorous water exchange during high wind and waves. The directions of wind and waves significantly affect the spatial distributions of the residence time and the age. This implies that the hydrodynamic processes in the Dongsha Atoll would have significant seasonal variability. This study presents different circulation patterns in an atoll system influenced by calm weather and strong wind/waves. [ABSTRACT FROM AUTHOR]

Gangnan Reservoir is an important water source of Shijiazhuang, the seat of northern China's Hebei Province. The irregular shape of the reservoir makes it easy for water to stop flowing in bays, forming dead water areas. Serious water quality problems will ensue. To disclose the influence of a water diversion project on the water exchange in Gangnan Reservoir, this paper sets up a hydrodynamic and water exchange model for the reservoir based on the convection–diffusion theory. According to different diversion flows and wind fields, a total of 12 working conditions was configured to numerically simulate the water exchange in the reservoir. The results show that: the diversion flow is the main factor affecting the water exchange rate. In the main reservoir areas, the water exchange rate increases gradually, finally, it can reach a relatively high level. In the bay areas, the water exchange rate is relatively small, and affected by the diversion flow and the bay location. The wind field has different impacts on the water exchange rate in the main reservoir areas and the bay areas. The impact is small in the former areas, yet significant in the latter areas. When it is not windy, the residence time decreases with the increase of the flow. When it is windy, the wind field of each direction shortened the residence time in the bay areas, while increased that in the main reservoir areas. Furthermore, the transport and diffusion law of water pollutants in Gangnan Reservoir was analyzed by the connectivity matrix: When the main reservoir areas are polluted, the pollutants greatly affect the main reservoir areas; When the bay areas are polluted, the pollutants only affect some adjacent water bodies. The research findings provide scientific reference for the diversion operation of Gangnan Reservoir. [ABSTRACT FROM AUTHOR]

A numerical model, validated with field measurements, was applied to comparatively reconstruct the hydrodynamics of a eutrophic coastal lagoon in a set of scenarios over the last two centuries. The effect of major morphological changes on the water exchange with the open sea and water residence time is evaluated. The results show that the number and morphology of the lagoon inlets are crucial in determining the volume of water exchanged with the sea, the water transport timescales, and the extent of poorly circulated stagnant areas with poor flushing potential, which are areas where anoxic crises might develop. When all the relevant forcing mechanisms on the hydrodynamics are considered, great variability of the water residence time is found in the different historical scenarios, with values varying between 83 and 305 days. The effect of anthropic actions on the system hydrodynamics was quantitatively evaluated, consolidating the background knowledge to support the present and future management of this environmental system. [ABSTRACT FROM AUTHOR]

Due to the high heterogeneity and complexity of water flow movement for multiple karst water-bearing mediums, the evaluation, effective development, and utilization of karst water resources are significantly limited. Matrix flow is usually laminar, whereas conduit flow is usually turbulent. The driving mechanisms of water exchange that occur between the karst conduit and its adjacent matrix are not well understood. This paper investigates the hydrodynamic characteristics and the mechanism of flow exchange in dual water-bearing mediums (conduit and matrix) of karst aquifers through laboratory experimentation and numerical simulation. A karst aquifer consisting of a matrix network and a conduit was proposed, and the relationship between the water exchange flux and hydraulic head differences generated from the laboratory experiments was analyzed. Two modes of experimental tests were performed with different fixed water level boundaries in the laboratory karst aquifer. The results indicate that the water exchange capacity was proportional to the square root of hydraulic head differences. The linear exchange term in the conduit flow process (CFP) source program was modified according to experimental results. The modified CFP and the original CFP model experimental data results were compared, and it was found that the modified CFP model had better fitting effects. These results showed that the water exchange mechanism between conduit and matrix is very important for solid-liquid interface reaction, water resource evaluation, and understanding of karst hydrodynamic behavior.© 2022 China Geology Editorial Office.

The Karimata Strait (KS) throughflow between the South China Sea (SCS) and Java Sea plays an essential role in heat and freshwater budget in the SCS and dual roles in strengthening/reducing the primary Indonesian throughflow (ITF) in the Makassar Strait. A sustained long-term monitoring of the ITF is logistically challenging and expensive; therefore, proxies are needed. Here, we use a combination of in situ measurement of the KS throughflow and satellite-derived sea surface height (SSH) and sea surface wind (SSW) to determine the interannual and decadal modulations in seasonal amplitude of the KS throughflow associated with El Niño-Southern Oscillation (ENSO), Indian Ocean dipole (IOD), Pacific Decadal Oscillation (PDO). Linear regression, correlation, harmonic and power spectrum analyses are used. The results manifest that there are significant interannual to decadal modulations in the seasonal amplitude of the KS throughflow. The modulations of the seasonal amplitude in the volume and heat transports range 1.36-1.92 Sv (1 Sv = 106 m3 s-1) and 126.41-173.36 TW (1 TW = 1012 W), respectively, with a significant cycle of ~9 years. From 1994 to 2020, the seasonal amplitude of volume transport through the KS shows an increasing trend of 37.75 ± 15.69 mSv decade-1 (1 mSv = 103 m3 s-1). The seasonal amplitude of the heat transport also increases, at a rate of 4.78 ± 1.52 TW decade-1. The KS volume transport is positively correlated with PDO and ENSO indices (r2 = 0.69 and r2 = 0.58), with a lag of 12 and 10 months, respectively. The results of composite analysis suggest that the interannual variability of the KS transport is related to the interannual anomalies of the SSH gradient and the local SSW fields in boreal winter.

Field experiment was conducted with six common winter wheat varieties in IPGR, Sadovo during 2020-2021 vegetation period. The gas exchange, relative chlorophyll content, canopy temperature depression, morphometry and leaf water exchange of the flag leaves were measured. After harvest the yield components were determinated. The main objective of this study was to determine the effect of water stress on response of photosynthetic activity, water exchange and yield in common winter wheat varieties. The better photosynthetic activity, presented by the parameters photosynthetic assimilation rate (A), intercellular (sub-stomatal) CO2 concentration (Ci) and stomatal conductance (Gs) during grain filling stage was reported for the varieties Sashez, Nadita and Yailzla compared to a standard Sadovo 1. The highest values of the morphometric parameters fresh weight, dry weight and relative chlorophyll content of flag leaves were expressed at the varieties Nadita Ð, Enola. From the analysis of the results for photosynthetic activity, leaf morphometry and water exchange, the most tolerant reaction to dry prone conditions can be determined in variety Nadita. The highest average yield was estimated for the varieties Avenue, Nadita and Enola. It was determinated the more intense physiological activity correlate with better yield in the varieties Nadita, Enola and Yailzla. [ABSTRACT FROM AUTHOR]

Background and Aims Trees interconnected through functional root grafts can exchange resources, but the effect of exchange on trees remains under debate. A mechanistic understanding of resource exchange via functional root grafts will help understand their ecological implications for tree water exchange for individual trees, groups of trees and forest stands. Methods To identify the main patterns qualitatively describing the movement of sap between grafted trees, we reviewed the available literature on root grafting in woody plants that focus on tree allometry and resource translocation via root grafts. We then extended the BETTINA model, which simulates mangrove (Avicennia germinans) tree growth on the individual tree scale, to synthesize the available empirical information. Using allometric data from a field study in mangrove stands, we simulated potential water exchange and analysed movement patterns between grafted trees. Key Results In the simulations, relative water exchange ranged between −9.17 and 20.3 %, and was driven by gradients of water potential, i.e. differences in tree size and water availability. Moreover, the exchange of water through root grafts alters the water balance of trees and their feedback with the soil: grafted trees that receive water from their neighbours reduce their water uptake. Conclusions Our individual-tree modelling study is a first theoretical attempt to quantify root graft-mediated water exchange between trees. Our findings indicate that functional root grafts represent a vector of hydraulic redistribution, helping to maintain the water balance of grafted trees. This non-invasive approach can serve as a basis for designing empirical studies to better understand the role of grafted root interaction networks on a broader scale. [ABSTRACT FROM AUTHOR]

Early assessment of tumor therapeutic response is an important topic in precision medicine to optimize personalized treatment regimens and reduce unnecessary toxicity, cost, and delay. Although diffusion MRI (dMRI) has shown potential to address this need, its predictive accuracy is limited, likely due to its unspecific sensitivity to overall pathological changes. In this work, we propose a new quantitative dMRI-based method dubbed EXCHANGE (MRI of water Exchange, Confined and Hindered diffusion under Arbitrary Gradient waveform Encodings) for simultaneous mapping of cell size, cell density, and transcytolemmal water exchange. Such rich microstructural information comprehensively evaluates tumor pathologies at the cellular level. Validations using numerical simulations and in vitro cell experiments confirmed that the EXCHANGE method can accurately estimate mean cell size, density, and water exchange rate constants. The results from in vivo animal experiments show the potential of EXCHANGE for monitoring tumor treatment response. Finally, the EXCHANGE method was implemented in breast cancer patients with neoadjuvant chemotherapy, demonstrating its feasibility in assessing tumor therapeutic response in clinics. In summary, a new, quantitative dMRI-based EXCHANGE method was proposed to comprehensively characterize tumor microstructural properties at the cellular level, suggesting a unique means to monitor tumor treatment response in clinical practice.

Study region: Patna is located on the southern bank of the River Ganges in Bihar, India. Rapid population growth over the past few decades has driven an increase in groundwater abstraction from aquifers under the city. Study focus: This study exeplores the pumping-induced water exchange between the River Ganges and groundwater under transient conditions between 2009 and 2015, using a numerical simulation. The deterministic water exchange model within an uncertainty quantification was used to reveal the controlling factors affecting river water infiltration. New hydrological insights for the region: Modelling reveals that under baseline (eno pumping) conditions, the dominant (~ 91% of the year) flow direction is from the aquifer to the river, which reverses (~ 9% of the year) when the river stage is high. When a municipal pumping well is implemented, river water infiltration into the aquifer increases to 68% of the year. The groundwater pumping rate is found to be the most important factor affecting the river water infiltration, whilst the groundwater table level is most sensitive to the well distance from the river, followed by pumping rate. Optimizing the location, depth and pumping rate of new wells in the area could mitigate fluvial contamination of the aquifer and help maintain groundwater levels.

As a semienclosed marginal sea, the Red Sea connects with the open ocean through a narrow strait at its southern end, known as the Bab-al-Mandeb (BAM) strait. The water exchange between the Red Sea and the Gulf of Aden at the BAM strait is crucial for the water mass transformations and thermohaline circulation in the Red Sea as well as for nutrient supply to the open ocean. In this study, a three-dimensional high-resolution nonhydrostatic MIT general circulation model (MITgcm) was used to investigate the tidal influence on the water exchange in the BAM strait through simulations with and without tidal forcing. We found that the tidal effects on the water exchange in winter were insignificant; however, the summer intrusion of the Gulf of Aden Intermediate Water (GAIW) was strongly affected. When the simulation includes tidal forcing, the along-axis northern extension of the GAIW intrusion is reduced by u to 100 km and the monthly mean volume transport is decreased by 20% on average. Two actors that possibly contribute to the hindrance effects of tides in summer are (i) the tidal residual currents that propagate in a direction opposite to the pathway of the GAIW intrusion currents nd (ii) the enhanced vertical mixing at the pycnocline and near the benthic topography of the BAM strait, which triggers more instabilities along the pathway of the intrusion.

Estuarine environmental capacity is the foundation for coastal biological diversity and self-purification capacity. Hence, studies on the marine environmental capacity (MEC) are the foundation for the total discharge control and water quality improvement of land-based pollutants. In the article, A calibrated two-dimensional hydrodynamic model was used to study the environmental characteristics of Sanmen Bay, including the tides, the residual currents, the tidal prism, and water exchange abilities. The model results were used to estimate the environmental capacity of the bay. Taking the pollution problem in Sanmen Bay as an example, the method of response factor, the sub-unit control method, and the phased control method were used to estimate the environmental capacity, pollutant amounts, and the pollutant reduction in the bay. The concentrations of COD, inorganic nitrogen, and acid salt in Sanmen Bay are spatially varied, with higher values occurring in the western part and in the inner bay. The half exchange time of the whole bay is about 23 days, and the exchange time of 95% water body is about 60 days. The evaluation of MEC cannot only provide technical support for the offshore aquaculture industries but also provide a scientific basis for the total control of terrigenous pollutants in coastal cities in Southern Zhejiang Province. [ABSTRACT FROM AUTHOR]

【Background and Objective】 Hetao irrigation district is one of the three mega-irrigation districts relying on Yellow river water for irrigation in China. However, the reduced water supply for the district to take for the river in the past decade has promoted the region to develop water-saving irrigation. Different agronomic and engineering methods have been developed, and the aim of this paper is to elucidate how to improve groundwater usage by crops by manipulating irrigation amount in regions with different groundwater depths. 【Method】 The experiment was conducted over the district by irrigating the crops three time during their growth season, with the irrigation amount at each growth stage varying from 90 to 135 mm. Added to this is a further irrigation in autumn with an irrigation amount of 300mm. The average annual groundwater depth in the experimental regions varied from 1.8 m to 2.0 m. In each treatment, we measured the change in soil water content and groundwater table before and after the irrigation. 【Result】 Average water content in the 0~60 cm soil changed significantly following irrigation, regardless of the irrigation amount. The first two irrigations in the crop growth season replenished the water in the tillage layer, while in the third irrigation 25% of the irrigation water leached to the subsoils. Overall, the larger the irrigation amount was, the more water would leach into the groundwater. The proportion of irrigation water leached to the groundwater increased with irrigation amount when the average annual groundwater depth was the same, and decreased with the groundwater depth when the irrigation amount was the same. 【Conclusion】 For areas with annual groundwater depth of 1.8 m, irrigating 90 mm in each of the three irrigations during the crop growth season, together with a 300 mm autumn irrigation, can significantly reduce irrigation water leaching and increase groundwater usage by the crops.

Catfish farming has long been carried out by local farmers with various systems and technologies. A reduction of land and water availability in urban aquaculture has been stimulate the application of aquaponic and biofloc technology. In this study, we aimed to analyze production performance, financial feasibility, and sensitivity analysis in catfish farming through a different farm system including water exchange system, aquaponic and biofloc technology. A case study was used from catfish (Clarias gariepinus) farmers in Bogor, West Java, Indonesia. The production performance analyzed is the total production, productivity and survival. Financial feasibility analysis used cost-benefit analysis (CBA) and sensitivity analysis is carried out on changes in the amount of production based on the survival value. The results showed that the best productivity of catfish was obtained from a water exchange system with a production value of 4038.0 ± 6.0 kg, productivity 168.0 ± 2.0 kg per m2, and the survival of 79.4 ± 2.2%. The financial feasibility analysis suggested that the water exchange system was US$ 4204.29 (NPV), 12.52 (BCR), and 301.82% (IRR), in the aquaponic was US$ 5048.3 6 (NPV), 12.57 (BCR) and 303.48% (IRR) and for biofloc technology was US$ 2242.23 (NPV), 7.67 (BCR), and 184.07% (IRR), analysis period was five years. The sensitivity analysis shows that the limit of reduction in survival value in water exchange catfish culture, aquaponic, and biofloc technology are 64.0%, 60.0% and 64.0% respectively. Our study showed that the production and financial performance of catfish farming using biofloc technology produces the lowest value compared to the other two systems. It was found that the farmers have not implemented the biofloc technology procedures correctly and have not routinely monitored water quality in all systems and technologies. Still, we were able to acknowledge this issue in hope that we can fix it in the future.

Formulation of the problem. Hydrocarbon pools in hydrodynamic traps are known within many oil and gas provinces. The Dnieper-Donets basin is one of the regions where non-vault traps of almost all types and associated with them hydrocarbon pools are widespread, while HT in DDD are not yet typical, although the geological structure of the region indicates the possibility of their formation. Thus, substantiation of the role of geological preconditions in the processes of hydrodynamic type traps formation is the main task of the work. Analysis of recent research and publications. In the monograph of O. Plotnikov (2001) among the promising regions for the search for HT defined DDD. The reason for this was the data on the presence in some productive horizons, in particular in the Sorochinsky and Rudenkivsky fields, of formation waters that lie above gas-bearing deposits. It is believed by some researchers, that the leading role in the formation of gas accumulations at these fields belongs to formation waters. According to the results of geological and geophysical study of the southern slope of the Kalmius-Torets depression and the Krasnoarmijska monocline in the south-eastern part of the DDD (A. Terdovidov (2000), S. Pavlov (2004), favorable geological prerequisites for the formation of HT in Paleozoic sediments established. Selection of previously unsolved parts of the overall problem. The general problem of searching for HT in the DDD as a whole task has not been solved so far. Formulation of the purpose of the article. Estimation of possibilities of a new direction of search and reconnaissance works in DDD, namely on non-traditional non-vault traps of hydrodynamic type substantiation. Results. The Visean dominant productive complex, regionally extended on the monocline slopes of the northern and southern sides of the depression and lithologically represented mainly by sandy horizons, was selected for priority research. The significant content of alluvial sandstones in Visean sediments section allowed the authors to consider them as special reservoirs of fluids, and paleoalluvial systems to study in the rank of independent search objects. Their territorial location is logically related to the existing deflections of the surface of the crystalline basement, most of which are associated with modern river systems, which indicates the current functioning of their relationship. The authors made an attempt to substantiate within the northern side of the DDD the following forecast water exchange systems: 1) expultional overflowing; 2) docking regime (both in the terminology of O. Plotnikov) in Paleozoic sediments; 3) infiltration water exchange in Mesozoic sediments, as necessary conditions for catching migrating upward hydrocarbons. The decrease in the infiltration waters velocity to insignificant values is interpreted by the authors as a typical phenomenon for "closed" monoclines, within which there was an equilibrium between the pressure of infiltrative waters and the resistance of expultional fluids. This equilibrium is seen as a term of creating conditions for hydrodynamic trapping. The conclusions emphasize the need for comprehensive research to confirm the predictive models of water exchange and obtain data for mapping piezometric minimums, where there is an presumable accumulation of hydrocarbons.

Purpose. The work is aimed at continuing the started in the previous papers investigations of structure of the Azov Sea salinity field based on the oceanographic survey data collected since 2000. Interest in studying this parameter is conditioned by its anomalous increase after 2006. Methods and Results. The data of 49 seasonal oceanographic surveys carried out in the Sea of Azov by the Azov-Black Sea Branch of "VNIRO" ("AzNIIRKH") from 2001 to 2016 permitted to calculate the following: the radii in the concentration region of the field spatial correlation function in the meridional and zonal directions for the surface and bottom layers (the characteristic of the field homogeneity); the ratio between these radii; the sea-average values of salinity field for the surface and bottom layers. The time graphical and the paired correlation analyses of the calculated indicators’ series were done. The average values of the meridional and zonal radii of the concentration region of the spatial correlation function (42.5 and 47.1 km) testify presence of two relatively isolated zones in the sea related to the water circulation. These zones are formed under the conditions of the eastern winds dominating in the region. The average values of the above-mentioned radii the near-bottom sea layer were approximately equal, whereas in the surface layer, the average zonal radii exceeded the meridional ones. In spring and summer, the meridional radius in the bottom layer surpassed the zonal one. Long-term variability shows that in the surface layer, the meridional radius values tend to increase, and in the bottom layer, the zonal radius ones – to decrease. These trends demonstrate a change in the nature of water exchange in the sea, namely from predominance of the zonal transport to that of the meridional one. Conclusions. Since 2006, the changes in the structure of the Azov Sea water salinity field (trends towards decrease of the zonal radii and increase of the meridional ones in the concentration region of the field spatial correlation function) resulted from decrease in the river water inflow and increase of water exchange with the Kerch Strait, and were accompanied by growth of average salinity. Water exchange with the Kerch Strait in the bottom layer was the most active in spring and summer. The anticipatory shift of the field structural characteristics by 1 and 2 years relative to its average values makes it possible to forecast them with a two-year advance time.

The Three Gorges Reservoir (TGR) operation has profoundly altered the hydrological regimes and ecosystem in the middle and lower Yangtze River basin. Its impacts on the river flow regime, sedimentation, lake level decline, and biodiversity have been extensively studied. However, the quantitative influence of the TGR on the downstream water exchange between the Yangtze River and Poyang Lake is lacking attention. In this study, we developed a machine learning model to investigate the river–lake water exchange variations under the TGR operation in typical hydrological years, compared with the natural scenario (i.e., no TGR). The results show that the machine learning model could provide a fast and accurate approach to identify the long-distance impact of reservoirs. The operation of the TGR has significant effects on the water exchange between the Yangtze River and Poyang Lake in the impounding period, with a 10,000 m³/s decrease in reservoir discharge approximately causing a 4,000 m³/s decrease in river–lake water exchange in the dry year and a decrease of 6,000 m³/s and 8,000 m³/s in reservoir discharge causing an increase of 4,000 m³/s and 6,000 m³/s in the normal year and the wet year, respectively. The TGR effect varies with different hydrological conditions of the river and lake, showing longer time range (from May to October) and greater degree (1.5 times the change rate in other years) in the wet year. The TGR operation is beneficial to the water maintenance of the lake in the dry year and flood control in the lake area in the wet year. This study provides a constructive approach and valuable information for decision making in water resource management and ecosystem protection in large river–lake systems.

Research on water exchange in frogs has historically assumed that blood osmotic potential drives water exchange between a frog and its environment, but here we show that the "seat patch" (the primary site of water exchange in many anurans), or other sites of cutaneous water uptake, act as an anatomic "compartment" with a water potential controlled separately from water potential of the blood, and the water potential of that compartment can be the driver of water exchange between the animal and its environment. We studied six frog species (Xenopus laevis, Rana pipiens, R. catesbeiana, Bufo boreas, Pseudacris cadaverina, and P. regilla) differing in ecological relationships to environmental water. We inferred the water potentials of seat patches from water exchanges by frogs in sucrose solutions ranging in water potential from 0 to 1000‐kPa. Terrestrial and arboreal species had seat patch water potentials that were more negative than the water potentials of more aquatic species, and their seat patch water potentials were similar to the water potential of their blood, but the water potentials of venters of the more aquatic species were different from (and less negative than) the water potentials of their blood. These findings indicate that there are physiological mechanisms among frog species that can be used to control water potential at the sites of cutaneous water uptake, and that some frogs may be able to adjust the hydric conductance of their skin when they are absorbing water from very dilute solutions. Largely unexplored mechanisms involving aquaporins are likely responsible for adjustments in hydric conductance, which in turn, allow control of water potential at sites of cutaneous water uptake among species differing in ecological habit and the observed disequilibrium between sites of cutaneous water uptake and blood water potential in more aquatic species. [ABSTRACT FROM AUTHOR]

Water exchange (WE) and artificial intelligence (AI) have made critical advances during the past decade. WE significantly increases adenoma detection and AI holds the potential to help endoscopists detect more polyps and adenomas. We performed an electronic literature search on PubMed using the following keywords: water-assisted and water exchange colonoscopy, adenoma and polyp detection, artificial intelligence, deep learning, neural networks, and computer-aided colonoscopy. We reviewed relevant articles published in English from 2010 to May 2020. Additional articles were searched manually from the reference lists of the publications reviewed. We discussed recent advances in both WE and AI, including their advantages and limitations. AI may mitigate operator-dependent factors that limit the potential of WE. By increasing bowel cleanliness and improving visualization, WE may provide the platform to optimize the performance of AI for colonoscopies. The strengths of WE and AI may complement each other in spite of their weaknesses to maximize adenoma detection.

The reaction of horse chestnut to rejuvenation pruning has been studied by the following morphophysiological parameters: water regime, pigments content, morphometric parameters of annual growth and organs of assimilation. In the course of the study, it was found that the leaves of rejuvenated plants are characterized by a lower water retention capacity and a significant water deficit compared to control plants. The intensity of transpiration of the experimental plants exceeds this indicator by 1.55-2.60 times compared to the control trees. The chlorophyll content in the leaves of rejuvenated plants is also higher by an average of 20% (especially chlorophyll b). An intensification of growth processes is observed after crown pruning, especially the length of annual shoot due to the length of internodes. The size and number of assimilation organs also increases in rejuvenated horse chestnut trees.

Study Region: The Yangtze-Poyang river-lake system (YPRLS) which includes the Poyang Lake, and the middle reach of Yangtze River basin. Study Focus: The water exchange in the YPRLS is complex and vital to the dynamic of it, thereby requiring well simulation. Nevertheless, existing numerical models have shortages in accuracy, efficiency and revealing potential relationships. Thus, for providing an accurate and efficient statistical model as a fundamental tool for investigating the effects of changing environment on the YPRLS, we developed the Yangtze-Poyang water exchange statistic (YPWES) model. In this study, the YPWES model was employed to simulate the water exchange in the YPRLS from 1971 to 2016 and improve our understanding of the backflow from the river to lake (BRL) in the YPRLS.New Hydrological Insights for the Region: Based on a physic-based lumped framework, the established YPWES model is basically more accurate and efficient than nine existing models. Meanwhile, 93% of the BRL event will occur when the value of discharge identification function (DIF) is 9.2–10.0 m, while the threshold range of the DIF corresponding to the BRL event occurrence was smaller after 2003 because the discharge-stage relationship changes with the Yangtze River streamflow when the BRL event occurs. Our work provides a valuable model and may help to investigate the cause and influence of the water exchange in the YPRLS.

Abstract Research on water exchange in frogs has historically assumed that blood osmotic potential drives water exchange between a frog and its environment, but here we show that the “seat patch” (the primary site of water exchange in many anurans), or other sites of cutaneous water uptake, act as an anatomic “compartment” with a water potential controlled separately from water potential of the blood, and the water potential of that compartment can be the driver of water exchange between the animal and its environment. We studied six frog species (Xenopus laevis, Rana pipiens, R. catesbeiana, Bufo boreas, Pseudacris cadaverina, and P. regilla) differing in ecological relationships to environmental water. We inferred the water potentials of seat patches from water exchanges by frogs in sucrose solutions ranging in water potential from 0 to 1000‐kPa. Terrestrial and arboreal species had seat patch water potentials that were more negative than the water potentials of more aquatic species, and their seat patch water potentials were similar to the water potential of their blood, but the water potentials of venters of the more aquatic species were different from (and less negative than) the water potentials of their blood. These findings indicate that there are physiological mechanisms among frog species that can be used to control water potential at the sites of cutaneous water uptake, and that some frogs may be able to adjust the hydric conductance of their skin when they are absorbing water from very dilute solutions. Largely unexplored mechanisms involving aquaporins are likely responsible for adjustments in hydric conductance, which in turn, allow control of water potential at sites of cutaneous water uptake among species differing in ecological habit and the observed disequilibrium between sites of cutaneous water uptake and blood water potential in more aquatic species.

Vertical wall breakwater with culvert (VWBC) is an environmentally friendly way proposed for the encircled harbor basin, which can break waves and allow the current to pass through. This paper adopts a theoretical analysis combining physical experiments and computational fluid dynamics (CFD) numerical simulations to study the hydrodynamic performance of the VWBC and to propose an optimal culvert for engineering applications. Based on a linear wave theory, theoretical analysis demonstrates the interaction between waves and the VWBC through the matched eigenfunction expansion method. The effects of the structural parameters (culvert and rubble mound foundation) on the hydrodynamic performances, such as the wave transmission coefficient (berthing stability), wave force (structure stability), and oscillatory flow (water exchange) inside the culvert are taken into consideration. Newly designed physical experiments and CFD numerical simulations are performed to verify the correctness of the theoretical analysis and to reveal the nonlinear characteristics of the wave transmission and oscillatory flow. It is found that the berthing stability and water exchange are mainly affected by the length and height of the culvert as well as the rubble mound foundation, and a total transport flow toward the harbor basin will be produced with an increase in wave height. Furthermore, the optimal culvert is obtained through the theoretical analysis. With the optimal culvert, VWBC can improve the berthing and structure stability, further promote the water exchange, and enhance the environment in the harbor basin. [ABSTRACT FROM AUTHOR]

Purpose. The work is aimed at studying the components’ intra- and inter-annual variability in the water exchange between the Sivash Bay and the Sea of Azov through the Tonky Strait at the current climatic period based on the empirical conversion schemes and using the hydrometeorological observation data obtained at the nearby stations. Methods and Results. Using the data on the sea level, and the wind direction and speed, the runoffs of the Azov Sea and the Sivash Bay waters in the Tonky Strait during 1966–2013 are calculated by two methods developed by Slatinsky Yu.G. in 1969 and Raskin L.G. in 1992. Predominance of the Azov currents over the Sivash ones is revealed. Seasonal and long-term dynamics of the runoff values in the strait are given based on the monthly average and annual average data. The data on the wind regime variability in the Genichesk region, and the sea level at the Genichesk meteorological station and at the Chongarsky bridge meteorological post are cited. Conclusions. The calculations show that the average annual inflow of the Azov waters through the Tonky Strait varies within the wide range 0.3 km3 – 1.18 km3, and the outflow of the Sivash waters constitutes on average 0.26 km3 per year. Difference between the water inflow and outflow in the strait is characterized by high inter-annual variability. Over the whole period under study, it amounted on average up to 0.45 km3. In the components’ spectrum of water exchange between the Sivash Bay and the Azov Sea, distinguished are the ~ 4 year fluctuations of the Sivash waters outflow from the bay, and the 3 and 5–6 year fluctuations of the Azov Sea waters inflow to the Sivash Bay. Multi-year variability of the Sivash water outflow with the 4 year periodicity is conditioned by the same precipitation amount periodicity over the Sivash Bay.

The high incidence of colorectal cancer and the occurrence of interval cancers after screening colonoscopy support the need to develop methods to increase adenoma detection rate (ADR). This review focuses on the importance of ADR and the impact of new techniques on ADR based on meta-analysis data. The low-cost interventions (such as water-aided colonoscopy, second observation, and dynamic position change) were effective in increasing ADR. So were enhanced imaging techniques and add-on devices. Increase with higher cost interventions such as newer scopes is uncertain. Water exchange (WE) has the highest ADR compared with water immersion, air insufflation, and carbon dioxide insufflation. Second observation with forward or retroflexed views improved the right colon ADR. Add-on devices result in only modest improvement in ADR, of particular help in low performing endoscopists. The second-generation narrow-band imaging (NBI) provided a two-fold brighter image than the previous system. The improvement in ADR with NBI required the “best” quality bowel preparation. New endoscopic techniques incur various additional costs, nil for WE, small for tip attachments but large for the newer scopes. In conclusion, one or more of the above methods to improve ADR may be applicable in Taiwan. A comparison of these approaches to determine which is the most cost-effective is warranted.

The ability of plants to absorb CO2 for photosynthesis and transport water from root to shoot depends on the reversible swelling of guard cells that open stomatal pores in the epidermis. Despite decades of experimental and theoretical work, the biomechanical drivers of stomatal opening and closure are still not clearly defined. We combined mechanical principles with a growing body of knowledge concerning water flux across the plant cell membrane and the biomechanical properties of plant cell walls to quantitatively test the long-standing hypothesis that increasing turgor pressure resulting from water uptake drives guard cell expansion during stomatal opening. To test the alternative hypothesis that water influx is the main motive force underlying guard cell expansion, we developed a system dynamics model accounting for water influx. This approach connects stomatal kinetics to whole plant physiology by including values for water flux arising from water status in the plant .

Physical forcings affect water exchange in coral reef atolls. Characteristics of the consequent water exchange depend on the atoll morphology and the local atmospheric and hydrographic conditions. The pattern of water exchange at the Dongsha atoll under the influences of tides, wind, and waves was investigated by conducting realistic modeling and numerical experiments. The analyses suggest that the southwestern wind could enhance the inflow transports at the southern reef flat and the outflow transports at the northern reef flat/north channel. The northeastern wind induces an inversed pattern. Unlike the wind, the waves always strengthen the inflow transports at the reef flat, and the locations of strengthened transports depend on the incident directions of the waves. Wind and waves induce shorter hydrodynamic time scales than tides, suggesting more vigorous water exchange during high wind and waves. The directions of wind and waves significantly affect the spatial distributions of the residence time and the age. This implies that the hydrodynamic processes in the Dongsha Atoll would have significant seasonal variability. This study presents different circulation patterns in an atoll system influenced by calm weather and strong wind/waves.