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Dams are one of the larger infrastructures of human civilization in the 21st century and subjected to increasing safety monitoring in the frame of global change. The quick development of SAR interferometry and processing capabilities allow near-real time monitoring of dams and associated areas and infrastructures. A pilot project for the surveillance and management of embankment dams, EyeRADAR-Dam has been developed in an industry-academia collaboration, supported by scientific validation. The potential of EyeRADAR-Dam lies in the integration via API of monitoring data and SAR time series dating from 1992 to present. The processed SAR data is input to the platform, together with relevant monitoring data (climate, topography, geotechnics, hydrology, flows...). A two-scale approach allows monitoring the entire reservoir, with slopes and infrastructures as a whole while simultaneously monitoring in detail critical infrastructures and dam body. EyeRADAR-Dam is part of a new generation of management platforms that integrate space data in daily operations. [ABSTRACT FROM AUTHOR]

Determination of seismic wave incidence angle is a critical step in performing seismic oblique incidence analysis of dams. However, for structures with complex dynamic responses, such as dams, it is difficult to derive the incident angle by traditional mathematical methods. For this reason, this paper proposes a method for determining the seismic wave incidence angle based on the dynamic response of the dam. The model calculates the dynamic response of the dam under different incidence angles of seismic waves, establishes the mapping relationship between the dynamic response and the incidence angle by using a hybrid particle network, and performs feature screening to obtain the optimal inversion features by the SHAP method, and then constructs the optimal inversion model. The results show that there is a significant correlation between the dynamic response of the dam body and the incident angle, the correlation coefficients of the model are all greater than 0.96, and the average absolute percentage errors are less than 5 %, which proves that the model can effectively invert the incident angle. The method can also be applied to the seismic safety analysis of other structures, providing a new way to determine the seismic wave incidence angle. [ABSTRACT FROM AUTHOR]

Recovering structures from images with 180 ∘ or 360 ∘ FoV is pivotal in computer vision and computational photography, particularly for VR/AR/MR and autonomous robotics applications. Due to varying distortions and the complexity of indoor scenes, recovering flexible structures from a single image is challenging. We introduce OmniSRNet, a comprehensive deep learning framework that merges distortion-aware learning with bidirectional LSTM. Utilizing a curated dataset with optimized panorama and expanded fisheye images, our framework features a distortion-aware module (DAM) for extracting features and a horizontal and vertical step module (HVSM) of LSTM for contextual predictions. OmniSRNet excels in applications such as VR-based house viewing and MR-based video surveillance, achieving leading results on cuboid and non-cuboid datasets. The code and dataset can be accessed at https://github.com/mmlph/OmniSRNet/. [ABSTRACT FROM AUTHOR]

Ethion is a class II moderately toxic organothiophosphate pesticide. The main objective of this study was to evaluate the maternal and foetal toxicity of ethion in rats. Pregnant rats were divided into 5 groups. Group I served as control. Group II, III, IV, and V were orally administered with 0.86, 1.71, 3.43, and 6.9 mg/kg of ethion respectively, from gestational day (GD) 6–19. Dams were sacrificed on GD 20. Maternal toxicity was assessed by body weight gain, foetal resorptions, oxidative stress, liver and kidney function tests, and histopathology. Foetal toxicity was assessed by physical status, gross, teratological and histopathological examination. Ethion caused dose-dependent reduction in maternal body weight gain, increased resorptions, and reduced gravid uterine weights. Elevated MDA levels and altered levels of GSH, SOD and catalase were recorded in pregnant dam serum and tissues. SGOT, SGPT, total bilirubin, urea, uric acid, and creatinine were elevated in ethion groups indicating liver and kidney toxicity. Histology of uterus revealed myometrial degeneration and mucosal gland atrophy in uterus of pregnant dams and degenerative changes in placenta. It showed histological alterations in liver, kidney, and lungs. There was reduction in the foetal body weights and placental weights, and degenerative changes in the foetal liver and kidney. Gross evaluation of foetuses showed subcutaneous hematoma. Skeletal evaluation showed partial ossification of skull bones, costal separation, and agenesis of tail vertebrae, sternebrae, metacarpals and metatarsals. The findings reveal that prenatal exposure to ethion caused maternal and foetal toxicity in rats. • Ethion is a class II moderately toxic organothiophosphate pesticide. • This study investigated the maternal and foetal toxicity caused by ethion. • It caused reduced weight gain, histological changes, and oxidative stress in dams. • It reduced foetal weight and caused histological changes in the liver and kidney. [ABSTRACT FROM AUTHOR]

Keeping replacement heifers that were the progeny of primiparous cows mated by artificial insemination enhances rates of genetic gain. Previous research has shown that heifers that were the progeny of primiparous cows were lighter at birth and grew at a slower rate to first calving compared with heifers born to multiparous dams. Furthermore, heifers that were heavier before first calving produced more milk than did lighter heifers. This study aimed to determine whether there were body weight, milk production, or reproductive disadvantages for heifers born from primiparous compared with multiparous dams. Data comprised body weight records from 189,936 New Zealand dairy heifers. Dams were allocated to 4 groups according to their age: 2 yr old (n = 13,717), 3 yr old (n = 39,258), 4 to 8 yr old (n = 120,859), and 9 yr or older (n = 16,102). Heifers that were the progeny of 2-yr-old dams were lighter from 3 to 21 mo of age than heifers that were the progeny of 3-yr-old and 4- to 8-yr-old dams. The progeny of 2- and 3-yr-old dams produced similar milk solids yields (± standard error of the mean) during their first lactation (304.9 ± 1.6 and 304.1 ± 1.5 kg, respectively), but more than that of 4- to 8-yr-old dams (302.4 ± 1.5). Furthermore, the progeny of 2-yr-old dams had similar stayabilities to first, second, and third calving to that of the progeny of 4- to 8-yr-old and ≥9-yr-old dams. Reproductive performance, as measured by calving and recalving rates was similar in first-calving heifers of all age-of-dam classes. Additionally, second and third calving rates were similar for the progeny of 2- and 3-yr-old dams. Interestingly, the progeny of dams ≥9 yr old had the lowest milk solids production in first (297.8 ± 1.6 kg), second (341.6 ± 1.8 kg), and third lactations (393.2 ± 2.4 kg). Based on the results of this study, keeping replacements from dams aged 9 yr and over could not be recommended. Furthermore, heifers born to 2-yr-old dams were lighter but produced more milk than heifers from older dams, in addition to having superior genetic merit. [ABSTRACT FROM AUTHOR]

La perte de contact entre le disque articulaire et le condyle mandibulaire de l'ATM, et la mise en tension des muscles ptérygoïdiens latéraux qui sont attachés au disque articulaire, peuvent induire un Dysfonctionnement de l'Appareil Manducateur (DAM), autrefois appelé SADAM. Cette affection touche 5 % des hommes et 10 % des femmes au moins une fois dans leur existence. Il combine en proportions variables des douleurs et des claquements des ATM, des otalgies/acouphènes induits par l'ouverture de la bouche, et des syndromes myo-fasciaux des muscles de voisinage (muscles massétérins, temporaux), ou plus lointains (sterno-cleïdo-mastoïdiens, scalènes, trapèzes), à l'origine de cervicalgies et céphalées à prédominance temporale et occipitale. En présence d'un syndrome SADAM il faut rechercher : (1) une douleur avec « clic » de l'ATM à l'ouverture de la bouche, qui est réduite à moins de trois travers de doigts, et se fait avec un trajet en baïonnette ; (2) une dysmorphose maxillo-mandibulaire (prognathisme ou rétrognathisme) ; (3) un trouble de l'occlusion dentaire (perte de dents postérieures qui peut faire reculer la mandibule par exemple), voire ; (4) une interposition linguale exagérée lors des 2500 efforts quotidiens de déglutition ; (5) une scoliose cervicale, ou une asymétrie visuelle ou auditive, majorant encore les syndromes myo-fasciaux ; (6) un stress ou un contexte de fibromyalgie, même si ce ne sont que des facteurs aggravants. L'équilibration de l'occlusion dentaire, la rééducation spécialisée semblent les plus efficaces, visant surtout à ré-harmoniser le couple disque et condyle, les gouttières ne paraissant pas efficaces contrairement aux espoirs passés. La prise en charge de l'anxiété et l'avis d'un(e) orthophoniste peuvent être nécessaires. Contact loss between the articular disc and the TMJ mandibular condyle, and the excessive stress on lateral pterygoid muscles can lead to temporo-mandibular dysfunction (TMD) in roughly 5% of people (twice more often in females). The TMD syndrome is a mix of pain and cliking arising from temporo-mandibular joint, sometimes associated with otalgia or tinnitus, and regional hypersensitivity, with myo-fascial pain of neighbouring muscles (masseter, temporalis, and sometimes sternocleidomastoid, scalenus, trapezus). Main symptoms are TM pain, often combined with cervicalgia and temporal and occipital headaches. Tinnitus and otalgia can also be found and are suggestive of the diagnosis when they occur during mouth opening. Pain in the throat and the face can also be noticed. A tenderness of the temporo-mandibular joint, an audible "click", and an asymmetrical opening of the mouth, reduced to less than three fingers, are main findings. Several underlying disorders must be searched for: (1) malocclusion, sometimes induced by orthodontics treatments; (2) inappropriate dental prosthesis; (3) maxillo-mandibular dysmorphosis; (4) abnormal deglutition with tongue interposition during the 2500 oral stages of swallowing, so that speech therapist advice can be welcome; (5) cervical scoliosis and asymmetrical hearing or sight can worsen myofascial syndromes; (6) stress and fibromyalgia can coexist but are not the main source of TMD. Occlusal treatment, physiotherapy, cognitive-behavorial treatment seem the most useful treatments of this frustrating disorder, soft occlusal splint therapy being little effective. [ABSTRACT FROM AUTHOR]

The impact of dam on the distribution and transformation of elements in riparian zones has received increasing attention. However, previous studies mainly focused on the site scale, with limited investigation at the particle scale, although the particle size is an important sediment property affecting solute and contaminant adsorption and desorption. In this study, we collected sediment particles from a dam-adjacent riparian zone and analyzed the content of iron (Fe) species and sediment particle surface morphology. Results showed that dam significantly altered sediment particle surface morphology, but had no significant influence on Fe mineral types or the relative sequence of different Fe species. In the upstream riparian zone, Fe contents in particles of varying sizes followed the sequence: 250−1000 μm > 5−20 μm > 20−50 μm > 50−250 μm. Conversely, in the downstream riparian zone, this sequence shifted to 5−20 μm > 20−50 μm > 50−250 μm > 250−1000 μm. Additionally, the total Fe contents in various-sized particles were higher in the upstream riparian zone than in the downstream riparian zone. These differences were attributed to the sediment particle surface properties influenced by dam-regulated hydrodynamic processes. In the upstream riparian zone, the sediment particle surface exhibited rough textures and were covered with numerous Fe-rich fine particles, resulting in higher Fe content, particularly in 250–1000 μm sediment particles. In contrast, in the downstream riparian zone, sediment particle surfaces were smoother, leading to lower Fe content. In both upstream and downstream riparian zones, the relative content of different Fe species in sediment particles of varying sizes generally followed the sequence: Silicate-associated Fe ≫ crystalline Fe oxides > poorly crystalline Fe oxides > carbonate-associated Fe/metastable Fe(II) sulfides. However, the mass contents of Fe oxides and carbonate-associated Fe/metastable Fe(II) sulfides in 5–50 μm sediment particles exceeded those in 50–1000 μm sediment particles. In addition, the rates of Fe(II)/Fe(III) cycling in 5–50 μm sediment particles were higher. This study elucidated the previously overlooked role of dam in influencing the distribution and transformation of Fe in riparian sediments at the particle scale. [Display omitted] • Influence of dam on solid phase Fe species at the particle scale was first investigated. • Dam changed the Fe distribution in sediment particles. • The influence was attributed to the modification sediment particle surface properties by dam. • Particle size exerted a great influence on the redox reactivity of solid Fe species. • Dam magnified the difference in reactivity between 50 and 1000 and 5−50 μm sediment particles. [ABSTRACT FROM AUTHOR]

Diode Area Melting (DAM) is an innovative approach to laser powder bed fusion. This research for the first time utilized multiple low wavelength (450 nm) and low power lasers (4 W each) to simultaneously process Ti6Al4V from a powder bed, resulting in high density samples (> 99%). The use of nine lasers perpendicular to the scanning direction allowed for the creation of melt pools with widths larger than 1000 µm, reducing the number of passes within a layer compared to traditional single laser LPBF systems. However, the increase in melt pool width creates challenges related to maintaining uniform melt pool penetration depths, this intern creates issues achieving high density in multi-layer parts. A parameter map based on normalized energy density was created. The research also investigated the effect of variable process conditions (scanning speed, hatch distance, and layer height), normalized energy density on densification, microstructure, and hardness. Implementing a rescanning strategy on each layer reduced average surface roughness and increased density while reducing hardness by approximately 40%. X-ray Diffraction analyses showed that the β phase occurred with increased energy density in as-built samples. Coarser lamellar structures were observed in the lower sections due to slower cooling rates, while finer, more martensite structures were observed towards the top, resulting in a basket-weave type microstructure throughout the sample. Furthermore, the lamellar sub-grains were visible without etching. This innovative technology shows that an array of low-power lasers can melt and fuse Ti6Al4V powder to create dense samples. • A unique approach utilizing nine adjacent 450 nm 4 W diode lasers to melt Ti-6Al-4V (Ti64) powder, offering a new perspective in multi-laser PBF technology. • The study successfully developed a parameter map for Ti64 based on normalized energy density. • The crescent effect phenomenon discovered due to the irradiated melt pool width from the laser array. • The study achieved samples with a density of 99.3% and reduced the hardness by approximately 40% by implementing a rescanning strategy. • The presence of lamellar α + β structures were found in as-built condition DAM samples. [ABSTRACT FROM AUTHOR]

Microplastic pollution is ubiquitous in freshwater environments, including rivers, lakes, and reservoirs. Plastic particles can accumulate in the sediment mainly in lentic environments offering several risks to the benthic community. While there are records on the distribution of microplastics in freshwater systems worldwide, limited research has been conducted on their distribution in reservoirs in the Southern Hemisphere. We investigated the levels of microplastic pollution in the sediments from the Billings Reservoir, Brazil, located in an area with high anthropogenic activities. Microplastics were recovered from all sediment samples, indicating their extensive distribution in the reservoir. Microplastic abundance in the sediment ranged from 11,800 to 31,900 particles.kg−1 dry weight. We observed different abundances between the shapes of microplastics: fiber > fragment > film > foam. Colorless fibers were the most abundant particles and small-sized (100 – 300 µm) microplastics were predominant. Of all the microplastics identified by FTIR, polyethylene was the most common type (25.0%), followed by polycarbonate, polypropylene, and nitrocellulose, each polymer representing 15.0% of the analyzed particles. The entry and the damming area of the reservoir seem to be more susceptible to the accumulation of microplastics in the sediment. This study was the first to report microplastic pollution in a Brazilian reservoir, which elucidates the incipience of the studies investigating microplastic pollution in Brazil. [Display omitted] • Tropical reservoirs are potential accumulation zones for microplastics. • High amounts of microplastics (20070 ± 6671.8 particles.kg−1) were found in Billings Reservoir. • Fibers were the most predominant shape in the sediment, followed by fragments. • PE, PC, PP, and nitrocellulose are the most frequent microplastic types found. • Microplastic pollution seems to be related to the critical state of conservation of the reservoir. [ABSTRACT FROM AUTHOR]

• Hydrologic alterations drive changes in physicochemical properties and Chl-a. • Higher TN:TP and lower NO 3 -N:DSi imply changes in phytoplankton composition. • Chl-a is less predicted by physicochemical variables in wet season rather dry. • Decoupling of relationships between physicochemical properties and Chl-a occurs. Periodically hydrologic alterations driven by seasonal change and water storage capacity management strongly modify physicochemical properties and chlorophyll- a (Chl- a) and their interactions in dam-induced lakes. However, the extent and magnitude of these changes still remain unclear. This study aimed to determine the effects of periodically hydrologic alterations on physicochemical variables and Chl- a in the dam-induced urban Hanfeng Lake, upstream of Three Gorges Reservoir. Shifts in Chl- a and 13 physicochemical variables were recorded monthly in the lake from January 2013 to December 2014. Chl- a was neither seasonal nor inter-annual differences while a few physical variables such as flow velocity (V) exhibited significantly seasonal variabilities, and chemical variables like total nitrogen (TN), nitrate-nitrogen (NO 3 -N), total phosphorus (TP), dissolved silica (DSi) were markedly inter-annual differences. Higher TN:TP (40:1) and lower NO 3 -N:DSi (0.8:1) relative to balanced stoichiometric ratios suggested changes in composition of phytoplankton communities and potentially increased proportion of diatom in Hanfeng Lake. Chl- a was predicable by combination of dissolved oxygen (DO), TN and DSi in dry season, and by V alone in wet season. During the whole study period, Chl- a was solely negatively correlated with TN:TP, indicating decline in N concentration and increase in P could therefore increase Chl- a. Our results highlight pronounced decoupling of linkages between Chl- a and physicochemical variables affected by periodically hydrologic alterations in dam-induced aquatic systems. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The aim of this paper is to study the performance of plasticised polyvinyl chloride (PVC) geomembranes used in the rehabilitation of concrete and masonry dams. In such applications, the geomembranes are left exposed on the upstream face, without external protection, to environmental factors and weather conditions, especially to UV rays. Evaluation of the performance and the lifetime assessment of the geomembranes is very important from a managerial point of view. Therefore, the results from a 25-year ongoing study on the long-term performance of PVC-P geomembranes installed on the upstream face of Italian dams are presented. The sampled geomembranes have been subjected to physical and mechanical tests and the results interpreted with reference to the variation of plasticiser, tensile characteristics, foldability at low temperatures, volumic mass and water vapour permeability. In the analysed samples, the loss of plasticiser range from 14.83% to 21.86%. This decrease in plasticiser content resulted in slightly higher modulus and tensile strength. The functionality of the geomembranes was not affected, as evaluated also by on site inspection. On the basis of the experimental results, lifetime predictions of the exposed geomembranes using the function of the loss of plasticiser were made. [ABSTRACT FROM AUTHOR]

Background: Remodeling of the uterine spiral arteries and blood vessels within the placenta allows delivery of nutrients to the growing utero-fetal-placental unit. While abnormal remodeling of these vessels is thought to play an important role in syndromes including intrauterine growth restriction and preeclampsia, there are a lack of studies that have quantified vascular remodeling in normal pregnant rats. Thus, the purpose of this study was to quantify time-dependent remodeling of the utero-placental vasculature during late gestation in normal pregnant rats.Methods: Timed-pregnant Sprague-Dawley rats were used. Gestational days of 14 and 19 were chosen because this when a large amount of fetal and placental growth occurs. A combined method of perfusion-casting and 3D micro-computed tomography were utilized to construct ex-vivo utero-placental vasculature images.Results: Significant spiral artery remodeling occurred between days 14 and 19. Vessel density shifted away from a distribution of smaller to larger diameters by day 19. Total spiral artery area and average diameter were increased by day 19. Moreover, branching and tortuosity of the spiral arteries were greater by day 19. In rodents, spiral arteries feed into the central canal vessels that funnel to sites of exchange. Canal vessel area and diameter were increased by day 19.Conclusions: Our study supports a quantitative method to examine the placental vasculature showing that significant vascular remodeling occurs during late gestation in the utero-placental-fetal unit of the normal pregnant rat. This method may serve as a tool to investigate fundamental pathophysiological mechanisms underlying placental-related diseases in rat models. [ABSTRACT FROM AUTHOR]

A combination of Geological mapping and two-dimensional electrical resistivity (2D-ER) surveys was applied to study the Unilorin Dam and its environment. The purpose of the study was to investigate the dam for structural anomalies that may compromise the purpose and safety of the dam. Field equipment for the study comprised a SuperSting R8/IP Multi-Electrodes Resistivity Meter, 84 metallic electrodes and the accessories, compass clinometer, and portable GPS equipment. Geological data were processed and plotted to obtain a Geological Map and Rosette Diagram that were used for structural interpretations. The structures interpreted include an asymmetric fold and a strike-slip fault. The 2D resistivity data were processed and tomographically inverted to obtain the resistivity models of the subsurface around the dam. Interpretations of 2D resistivity models showed that the dam reservoir floor is underlain by competent basement rocks, however, the basement rock is weathered in some places. Patches of low resistivities structures interpreted as seepages, fractures and water-saturated cavity were delineated in different sections of the dam. The surface structural elements from geological study support the subsurface structures interpreted in the 2D resistivity models. Weathered structures, fractures, and seepage in the reservoir floor constitute areas of excessive water loss in the dam. The cavity delineated in the dam foundation is a potential threat to the dam's safety. The dam section with cavity has been referred to structural engineers for detailed study. [ABSTRACT FROM AUTHOR]

Managed aquifer recharge (MAR) structure is widely used to expand groundwater resources. In arid regions with flash flooding, MAR can also be used as a flood control structure to decrease peak discharge of rivers. In this paper, we present a method for quantifying the role of MAR in head water systems and assess its impact on the total water balance in a river basin. The method is based on rainfall-runoff modeling, reservoir flood routing, recharge analysis and river flow analysis. For the case selected, Kamal Abad MAR in Lake Maharlou basin in southern Iran, we analyzed changes in the downstream river regime using two scenarios (with MAR and without MAR) with different return periods. The results revealed a significant impact of MAR on river flow in terms of changes in flow timing, magnitude and variability. With MAR, the ephemeral river studied became disconnected from the main stream, albeit, whereas the case without MAR, floods with return period higher than 10 years would be connected to the downstream. Even though, MAR structures are useful in arid and semi-arid climates for irrigation water supply, their placing and designing need more attention. The developed method can be used to assess the impacts of MAR on river flow and find the best location for it to make the connection of the ephemeral river and downstream river, an issue which has not received much attention in hydrological research. Unlabelled Image • Estimate the impact of Managed Aquifer Recharge (MAR) in arid and semi-arid region. • Develop a framework to assess the flow regime alteration due to MAR. • Evaluate the rate of groundwater recharge from reservoir and river due to MAR. [ABSTRACT FROM AUTHOR]

Abstract Wetlands (rivers, lakes, bogs, etc.), the biodiversity hotspots, provide habitats for biology on Earth and play an important role in biodiversity protection around the world. However, they are damaged by dam construction all over the world. Many studies have been conducted on the effects of dam construction on biodiversity, but a review about it is missing. The objectives of this review are: (1) to discuss the effects of dam construction on biodiversity in freshwater wetlands; and (2) to identify the future directions for research in this field. To achieve these objectives, 347 significant publications from 2000 to 2017 were selected (based on a rigorous screening processes and a systematic literature review approach) from the ISI Web of Knowledge database. Dam construction decreased the water fungal biomass and richness in reservoirs and downstream reaches, but increased the amount of soil microorganisms in downstream lake wetlands. The studies about effects of dam on benthos mainly focused on macroinvertebrate, periphyton and mussel. Most studies about the effects on macroinvertebrate claimed that dam construction caused increases in biomass and decreases in taxa richness in downstream reaches. The studies about effects of dam on plankton mainly focused on phytoplankton, zooplankton, planktonic microorganisms and ichthyoplankton. Effects of dam on fish (including aquatic mammals) included blocking migration route, habitat fragmentation, changing from lotic to lentic water in the impounded area, release of hypolimnetic cold water of reservoir, and changes of water flow in downstream reaches. Studies about effects of dam construction on botany mainly focused on the riparian plants, but there were few studies on floating plants and submerged macrophyte and effects of dam construction on botany in downstream lake wetlands. There were only few studies that examined these effects of dam on bird. We also pointed out the future directions for research in this field. Graphical abstract Image 1017 Highlights • The paper reviewed the effects of hydropower dam on biodiversity. • Dam effect microorganism, benthos, plankton, fish (aquatic mammals), botany& birds. • Dam blocked migration route, fragmented habitat, changed water environment. • It pointed out the immediate study needs arising & future directions for research. [ABSTRACT FROM AUTHOR]

Highlights • Backward elimination-partial least square (BE-PLS) method was used to establish the statistical model of dam displacement. • The relation between computations of the finite element model (FEM) and readings of the monitoring instrument was analyzed. • FEM computations were consistent with the components extracted from monitoring data in objective function of back analysis. • The rule of jumping out was used to prevent the particle swarm optimization algorithm from falling into the local solution. Abstract The elastic modulus of dam body and dam foundation is the important mechanical parameter affecting the strength and stability of dam. According to dam monitoring data and numerical simulation, establishing the statistical model and the objective function, the improved particle swarm optimization (PSO) algorithm is applied to back analysis of elastic modulus of dam body and dam foundation. Firstly, based on backward elimination-partial least square (BE-PLS) method, the statistical model of dam deformation monitoring data is established, and the water load component is separated from monitoring data. Meanwhile, the finite element model (FEM) of the dam is built and the displacement field of the dam is calculated. Secondly, according to the difference between the FEM computations and the reading of the plumb-line, the relation between the two objects is deduced, and an accurate objective function is established. Thirdly, in the optimized back analysis, the PSO algorithm with modified parameters is used to search the optimal elastic modulus, and the rule of jumping out makes the algorithm avoid falling into the local solution. Finally, taking a gravity dam as an example, the results demonstrate that the statistical model established by BE-PLS has high fitting precision, and that the new PSO algorithm improves the global optimization ability and convergence speed and can avoid falling into the local solution. The optimized back analysis can obtain the elastic modulus of dam body and dam foundation with high accuracy. [ABSTRACT FROM AUTHOR]

• We established large-scale patterns of hydrological alteration caused by dams. • We used a hydrological classification and we define types of altered regimes. • Variability of daily flows and high flow events were the most commonly altered features. • The hydrological alteration is influenced by the pre-dam nature of the altered rivers. • Types of altered regime and the purposes of the dams were not directly related. Nowadays, alteration of the natural flow regime is considered one the most widespread and damaging impacts for river ecosystems. Hence, increasing our understanding of large-scale hydrological alteration patterns would help us design more effective water use policies. The present study aims to establish general patterns of hydrological alteration caused by dams on a national level, with Spain as a case study. First, we developed a classification of the natural flow regime of the Spanish river network, which served as the reference to assess the degree of hydrological alteration of 139 altered-river gauges. In addition, using the flow series of the altered-river gauges we defined a set of 7 types of altered regimes (TARs), which allowed the stratification of the analyses. The results revealed that the magnitude and direction of hydrological alteration depended on the natural flow class of the altered rivers. In this regard, major effects of dams on Spanish rivers were related to the modification of the intra-annual variability of daily flow, the magnitude of seasonal maximum and minimum flows and the patterns of high flow events. Our results also showed that the distribution of the TARs partially followed a geographic order, but associations between TARs and natural flow classes were not straightforward. In addition, we highlighted that the nature of the hydrological alteration was independent of the registered dam uses. [ABSTRACT FROM AUTHOR]

Highlights • AcSVP2 regulates the timing of budbreak in a low-chill kiwifruit A. chinensis. • Histone modification plays a role in regulation of AcSVP2 expression. • Candidate transcription factors that may regulate AcSVP2 expression include homologs of SOC1. • Aspects of SVP and SOC1 interactions are conserved across distant taxa but may have no role in regulation of flowering time. Abstract The SHORT VEGETATIVE PHASE (SVP)- like and DORMANCY ASSOCIATED MADS-BOX (DAM) genes have been shown to regulate winter dormancy in woody perennials. In kiwifruit, AcSVP2 affects the duration of dormancy in cultivars that require high chill for dormancy release. In this study, we used a low-chill kiwifruit Actinidia chinensis 'Hort16A' to further study the function and regulation of AcSVP2. Overexpression of AcSVP2 in transgenic A. chinensis delayed budbreak in spring. A reduction in the active trimethylation histone marks of the histone H3K4 and acetylation of histone H3 contributed to the reduction of AcSVP2 expression towards dormancy release, while the inactive histone marks of trimethylation of the histone H3K27 and H3K9 in AcSVP2 locus did not show significant enrichment at the end of winter dormancy. Analysis of expression in shoot buds showed that AcSVP2 transcript was elevated in dormant buds during winter months and declined prior to budbreak, which was coordinated with expression of some of kiwifruit SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) -like genes. Screening of 101 transcription factors in an assay with a 2.3 kb promoter region of AcSVP2 found that kiwifruit SOC1 -like genes are able to activate the AcSVP2 promoter. We further identified additional transcription factors associated with drought/osmotic stress and dormancy which may regulate AcSVP2 expression. [ABSTRACT FROM AUTHOR]

Highlights • There a high environmental synchrony. • There a low populational synchrony. • The spatial distance was not related to the synchrony. • Synchrony change according to the reservoir construction phases. • Synchronous/asynchronous populations have potential applications in biomonitoring. Abstract The escalating demand for energy and the strong political and economic pressure to explore the Amazon's hydroelectric potential has led to the increase of hydroelectric reservoirs in the region. Reservoirs are artificial ecosystems that modify the structure of biological populations. Evaluating the spatial synchrony of populations and environmental variables in the development of reservoirs may reveal determinant factors and processes operating in these ecosystems. This may help understand the impacts, optimize monitoring systems and develop strategies to improve and maintain the ecological integrity (or stability) of these environments. In this study, we evaluated the spatial synchrony in zooplankton populations and limnological environmental variables during the implementation of a hydroelectric reservoir in the Amazon region, on the border of the states of Pará and Amapá. Synchrony was determined by mean cross-correlation between the pairs of points for each variable, followed by Mantel test to investigate its influencing factors. We observed spatial synchronous values for both population and limnological environmental variables. However, we could not identify the mechanisms that are operating, indicating that more than one factor may be influencing the ecosystem dynamics. Population synchrony increased after impoundment. Population synchrony may be associated with some limnological variables, such as the ones related to the amounts of nutrients, whereas environmental synchrony can be related to extrinsic factors, such as climatic variation, not tested this study. In order to increase the understanding of the mechanisms operating over population and environmental dynamics, we suggest that, besides evaluating limnological environmental variables and spatial synchrony, analyses should include meteorological and landscape data. [ABSTRACT FROM AUTHOR]

Abstract Only in the years 2007–2016 about 8000 large dams were constructed all over the world, adding to >50,000 previously built dams. These structures disturb abiotic and biotic components of rivers, but to date the knowledge of their impacts has been mainly derived from observations of downstream river reaches. Upstream from dams, however, backwater fluctuations induce sediment deposition, cause more frequent and higher valley-floor inundation, increase groundwater level, and change channel morphology and riparian vegetation. Little is known on the effects of these disturbances on the river biogeomorphological processes. In this review I synthesized knowledge on backwater effects on rivers into a model of backwater-induced abiotic–biotic interactions in the fluvial system. This model is next used to propose new hypotheses and research tasks concerning the biogeomorphology of gravel-bed rivers in the temperate climatic zone. Implications for flow–sediment–morphology–vegetation interactions and feedbacks are conceptualized in a river cross-section based on recent biogeomorphological insights and methodological approaches allowing to explore them in future studies. The model highlights that backwater-induced changes in abiotic and biotic components of river system trigger further feedbacks between them that additionally influence these components even without a direct backwater influence. Backwater-induced changes in hydrodynamics and sediment transport favour seed germination and growth of plants and decrease their mortality during floods, but also eliminate plants intolerant to prolonged inundation and intensive fine sediment deposition. These impacts may change the biogeomorphical structure of river system by modifying trajectories of biogeomorphic succession cycles and related zones of vegetation–hydromorphology interactions in the river corridor. Specifically, backwater effects may promote the development of more stable channel morphology and a less diverse mosaic of riparian vegetation and animals habitats, contrasting with those occurring in free-flowing rivers of the temperate zone. Graphical abstract Unlabelled Image Highlights • First conceptual model of backwater fluctuation (BF) effects on river ecosystem is proposed. • BF influences abiotic-biotic components of river and trigger feedbacks between them. • Flow-sediment-morphology-vegetation feedbacks on gravel-bed river is influenced by BF. • This influence river biogeomorphic succession cycles and vegetation zonation in BF zone. • BF zone biogemorphology is challenge for further multidisciplinary research. [ABSTRACT FROM AUTHOR]

Highlights • Compilation of knowledge gained during more than 30 years of experience. • Diagnostic procedure successfully applied in 15 dams with durability issues. • Selection of 4 case studies covering different pathologies. Abstract Studies on the diagnosis of pathologies of concrete dams are a valuable reference for professionals managing such assets. However, detailed information is rarely reported in the literature. This paper compiles the most important lessons learned during 30 years of practical experience in this area. The diagnostic procedure is illustrated through 4 of the most interesting dams analysed and monitored by the authors. All were subjected to a first stage that included inspection and analysis of historical documentation, leading to the proposal of a diagnose hypothesis. This was followed by a second stage that included an experimental programme with laboratory tests and, in some cases, numerical simulations to confirm or reject the hypothesis. The analysis of the information shows different pathologies and provide a wide spectrum of boundary conditions, symptoms and diagnoses (from internal sulphate attack and alkali-aggregate reaction to soil-structure interaction). [ABSTRACT FROM AUTHOR]

Abstract Reliability analysis of large coupled systems is a challenging task in dam safety. Not only the number of random variables is increased, but also a complex numerical model makes the simulations computationally expensive. To overcome this problem, an efficient analytical model should be developed which does not affect the accuracy of reliability analysis. In this paper, a gravity dam-foundation-reservoir coupled system is taken as a vehicle for the numerical simulations. Epistemic (i.e. material) uncertainties, as well as the ground motion record-to-record variability (i.e. aleatory) are incorporated in the simulations. A new reliability technique is proposed and its efficiency is compared to the Latin Hypercube Sampling (LHS). In this technique, a continuous probability density function is replaced by a finite number of fractional moments. Furthermore, an improved bivariate dimension reduction method is developed for dynamic systems. Several parametric simulations are performed to investigate the impact of the reservoir water level and the dam size. Results of the proposed method are in good agreement with the LHS. Finally, a response surface meta-model is proposed to estimate the dam behavior as a function of ground motion intensity measures. Highlights • An efficient reliability analysis technique id proposed for dynamical systems. • The proposed method accounts for both the epistemic and aleatory uncertainties. • Computational effort is considerably reduced compared to Latin Hypercube sampling. • Several parametric studies are performed on dam-reservoir-foundation coupled system. • A response surface meta-model is proposed for dam response. [ABSTRACT FROM AUTHOR]

Abstract Water regulation of the Xiaolangdi Reservoir of the Yellow River was chosen as a case to investigate variations in concentrations and bioavailability of heavy metals caused by water conservancy projects in rivers. Water and suspended sediment (SPS) samples were collected at downstream sampling sites along the river during this period. Concentrations and speciation of Zn, Cr, Cu, Ni, and Pb in water and SPS samples were analyzed, and their bioaccumulation was studied with Daphnia magna. This study indicated that the exchangeable and carbonate-bound fractions of heavy metals in SPS decreased along the studied stretch, and the dissolved heavy metal concentrations increased along the river with 1.6–15 folds. This is because sediment resuspension increased along the river during water regulation, giving rise to the increase of heavy metal release from SPS. The dissolved Zn, Cu, Ni, and Pb concentrations were significantly positively correlated with SPS concentrations, and their increase along the river was greater than Cr. The body burdens of heavy metals in D. magna exposed into samples collected from the reservoir outlet were 1.3–3.0 times lower than those from downstream stations, suggesting that the heavy metal bioavailability increased during water regulation. This should be considered in the reservoir operation. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract The capacity of water reservoirs may be considerably reduced by sediment transport and accumulation. This phenomenon may occur quickly in regions prone to erosion, such as Hammam Debagh Dam region in Algeria. For better management of water resources, it is important to estimate the volume of a reservoir by regular and frequent topo-bathymetric surveys. Topo-bathymetric surveys with a high point measurement density are expensive and time-consuming. To reduce this expense and to increase the frequency of topo-bathymetric surveys, it is required to optimize their size and density. The complete survey of the reservoir created by the Hammam Debagh Dam in Algeria was examined in comparison with 19 reduction subsets using geostatistics. The study showed that the complete dataset of 32,164 points, corresponding to a density of 42 points ha-1 could be reduced to 10,000 points, i.e. 13 points ha-1, without affecting the estimation of the water volume in the reservoir. This reduction could considerably simplify the work load, reduce the expenses to do these surveys, and, therefore, allow for an increased frequency of topo-bathymetric surveys. Highlights • It is important to estimate the volume of a reservoir by regular topo-bathymetric surveys. • Geostatistics were applied to 19 reduction subsets extracted from a survey of 32,164 points from the Hammam Debagh Dam in Algeria. • The original density of 42 points ha-1 could be reduced to 13 points ha-1, without affecting the estimation of the water volume in the reservoir. [ABSTRACT FROM AUTHOR]

Abstract The Social Impact Assessment (SIA) literature has highlighted the need to focus attention on the most vulnerable groups to improve the management of socio-environmental risk. However, methodological proposals to introduce vulnerability in SIAs are still incipient. The aim of this article is to present a proposal to analyze the role of social vulnerability in the production of risks generated by large infrastructure projects. Taking the theoretical-methodological advances made from the social vulnerability and natural disasters approach, and from the social vulnerability, development and poverty approaches, we have designed a Social Vulnerability Approach (SVA) which we aim at incorporating into the SIA of large infrastructure projects. To illustrate our methodological proposal, the case of the socio-environmental conflict generated by the HydroAysen Project (which entailed the construction of a set of hydroelectric dams on the Baker and Pascua rivers in the Chilean Patagonia region) has been selected. Our proposal allows us to identify elements of vulnerability throughout the whole project cycle and, therefore, windows for intervention in order to reduce social vulnerability as well as other kind of hazards that large infrastructure projects may generate on affected populations. Highlights • Social vulnerability is a process in two stages: the Structural and the Acquired. • SVA is apt for the diagnosis and management of social impacts caused by projects. • SVA is based on the Natural disaster and the Assets Based approaches. • Structural Vulnerability influences the very nature of the project. • Understanding the project as a possible hazard improves its analysis. [ABSTRACT FROM AUTHOR]

Emerging evidence suggests that immune receptors may participate in many aging-related processes such as energy metabolism, inflammation, and cognitive decline. CD300f, a TREM2-like lipid-sensing immune receptor, is an exceptional receptor as it integrates activating and inhibitory cell-signaling pathways that modulate inflammation, efferocytosis, and microglial metabolic fitness. We hypothesize that CD300f can regulate systemic aging-related processes and ultimately healthy lifespan. We closely followed several cohorts of two strains of CD300f−/− and WT mice of both sexes for 30 months and observed an important reduction in lifespan and healthspan in knockout mice. This was associated with systemic inflammaging, increased cognitive decline, reduced brain glucose uptake observed by 18FDG PET scans, enrichment in microglial aging/neurodegeneration phenotypes, proteostasis alterations, senescence, increased frailty, and sex-dependent systemic metabolic changes. Moreover, the absence of CD300f altered macrophage immunometabolic phenotype. Taken together, we provide strong evidence suggesting that myeloid cell CD300f immune receptor contributes to healthy aging. [Display omitted] • CD300f−/− mice show reduced lifespan, but no specific cause of death is identified • This is associated with inflammaging, senescence, frailty, and cognitive decline • CD300f−/− mice exhibit microglial aging states and sex-dependent metabolic changes • Absence of CD300f reduces macrophage immunometabolic fitness in a sex-dependent way Evans et al. report that the absence of CD300f myeloid cell immune receptor in male and female mice induces a reduced lifespan. Animals display diverse aged-related conditions such as inflammaging, frailty, cognitive decline, brain senescence markers, microglial aging phenotypes, and reduced macrophage metabolic fitness, as well as sex-dependent metabolic alterations. [ABSTRACT FROM AUTHOR]

Apolipoprotein E4 (APOE4) is an important driver of Tau pathology, gliosis, and degeneration in Alzheimer's disease (AD). Still, the mechanisms underlying these APOE4-driven pathological effects remain elusive. Here, we report in a tauopathy mouse model that APOE4 promoted the nucleocytoplasmic translocation and release of high-mobility group box 1 (HMGB1) from hippocampal neurons, which correlated with the severity of hippocampal microgliosis and degeneration. Injection of HMGB1 into the hippocampus of young APOE4-tauopathy mice induced considerable and persistent gliosis. Selective removal of neuronal APOE4 reduced HMGB1 translocation and release. Treatment of APOE4-tauopathy mice with HMGB1 inhibitors effectively blocked the intraneuronal translocation and release of HMGB1 and ameliorated the development of APOE4-driven gliosis, Tau pathology, neurodegeneration, and myelin deficits. Single-nucleus RNA sequencing revealed that treatment with HMGB1 inhibitors diminished disease-associated and enriched disease-protective subpopulations of neurons, microglia, and astrocytes in APOE4-tauopathy mice. Thus, HMGB1 inhibitors represent a promising approach for treating APOE4-related AD. [Display omitted] • APOE4 promotes neuronal HMGB1 translocation and release in tauopathy mice • Neuronal APOE4 removal reduces HMGB1 translocation and release in tauopathy mice • Treatment with HMGB1 inhibitors ameliorates APOE4-driven gliosis and AD pathologies • The inhibitor treatment reduces disease-associated neuronal and glial subtypes Nicole Koutsodendris et al. report that, in a tauopathy mouse model, APOE4 promoted intraneuronal translocation and release of HMGB1, which correlated with the severity of microgliosis and neurodegeneration. Treatment of APOE4-tauopathy mice with HMGB1 inhibitors effectively blocked the intraneuronal translocation and release of HMGB1 and ameliorated APOE4-driven Alzheimer's disease pathologies. [ABSTRACT FROM AUTHOR]

Earthquake-induced landslides, also called seismic landslides (SLs), are some of the most catastrophic natural hazards on the Tibetan Plateau (TP). They have frequently caused disastrous impacts on human society but are also important driving forces in regional evolution. The rapid development of multiple advanced techniques and more relevant studies have contributed to much progress in understanding SLs, but a synoptic survey that combines the insights of related studies to build a comprehensive understanding of SLs on the Tibetan Plateau is currently lacking. Here, we adopt recent SLs triggered by the 2005 Kashmir (Mw 7.6), 2008 Wenchuan (Mw 7.9), 2010 Yushu (Mw 6.9), 2013 Lushan (Mw 6.6), 2013 Minxian (Mw 5.5), 2015 Gorkha (Mw 7.8), 2017 Jiuzhaigou (Mw 6.5), 2017 Nyingchi (Mw 6.5), 2022 Lushan (Mw 5.8) and 2022 Luding (Mw 6.6) earthquakes on the TP to overview some advances in data preparation, spatial patterns and controls, landslide patterns and causes, movement and landslide damming, susceptibility, and long-term evolution. The study first summarizes worldwide seismic events that have triggered SLs since 2000 to confirm the TP is a SL-prone area and points out detailed SL-prone tectonic blocks on the TP. Based on landslide inventories of 10 adopted events, the study investigates the SL spatial distribution and finds tectonic and geomorphic controls of SL distribution. The landslide inventories also help us confirm the relationships of landslide sizes (SL number, SL area and SL volume) and magnitudes. Next, we summarize the landslide patterns and possible failure causes and highlight that seismic amplification could play an important role for SL occurrence on steep mountains. We use two important indicators, namely, landslide mobility (H/L) and landslide velocity, to reveal SL movement characteristics; we analyze the characteristics of SL damming, dam breaks and outburst floods; we analyze the SL susceptibility process and propose the most common landslide controlling factors (altitude, slope, PGA, seismogenic faults, rivers and stratigraphy) for SL susceptibility; we analyze postseismic evolution using two important indicators, namely, landslide activity and debris flow activity. Finally, we compare the results with other earthquakes worldwide and find that the TP is more sensitive to SLs; SL distribution laws of other worldwide seismic events are not fully consistent with those of the TP, including few seismic liquefaction landslides occur on the TP, while it is common for coastal earthquakes, and SLs on the TP require longer recovery periods. [ABSTRACT FROM AUTHOR]

• ABAQUS CDP model could well simulate the damage pattern of concrete slab subjected to underwater contact explosion. • Underwater contact explosion caused more serious damage compared to the air contact explosion. • For gravity dam, lowering water level reduced damages to the dam body (craters, punching damage, and stress concentration). • For arch dam, lowering water level reduced most damage except the arch end damage. In order to investigate the damage mechanism of dams subjected to underwater contact explosion, firstly, an experimental program was conducted with six concrete slabs and two explosive quantities. The test results showed that the diameter and depth of the crater on the front and back surface of the concrete slab increased with increasing explosive quantity with radial and circular cracks generated. Three different concrete material models were tested and it was found the CDP model was most suitable in simulating concrete subjected to underwater explosion. The calibrated models were used to conduct parametric studies to study the effect of explosive quantity, slab thickness, and transferring medium (water or air). Numerical analysis results showed that the diameter and depth of the crater on both the front and back surface of the concrete slab decreased with increasing slab thickness and decreasing explosive quantity. In addition, the damage caused by the air contact explosion was smaller and more concentrated in the detonation center compared with underwater contact explosion. Finally, a gravity dam and an arch dam were modeled to study the effect of detonation depth and water level on the damage distribution pattern of the dams. Based on the results, recommendations were provided for the anti-explosion protection design of hydraulic structures. [ABSTRACT FROM AUTHOR]

• A novel data-based modelling approach, (EOF) is introduced for riverine management. • The results showed significant similarity between simulated and observed patterns. • The natural forces were the main driving factor for the sediment load before 1988. • Anthropogenic pressure emerged as an important driver to the declining of sediment load since the end of 1988. This paper introduces a novel data-based modelling approach, Empirical Orthogonal Function (EOF), to characterize the sediment load variability at the downstream section of the Red River system in Vietnam. We modified the original EOF and performed it on the demeaned datasets of monthly total sediment load. Rating curves between the discharge and sediment load were used to validate the performance of EOF analysis. The results showed significant similarity between simulated and observed patterns. A dramatic decrease in sediment load has been observed via both the EOF and rating curve methods across the observation period (∼1958–2021), with two dramatic decreasing phases identified (1988–2008 and 2009-present). The variation in the sediment load was mainly related to the seasonal and inter-annual hydrological conditions in the basin, as well as the dam-reservoir impact. Before 1988, river discharge and rainfall were well correlated to the first EOF mode, indicating that the natural forces were the main driving factor for the sediment load. However, anthropogenic pressure (dam-reservoir impact) emerged as an important driver to the declining of sediment load since the end of 1988 and became more severe towards the end of 2008. We conclude that the modified EOF method developed in this study successfully demonstrates a simple and efficient means of reconstructing and evaluating the sediment load variability over time in data-poor regions, influenced by complex natural and anthropogenic – drivers. It can, thus, be useful for water resources management in ungauged basins in the region. [ABSTRACT FROM AUTHOR]

Few studies have assessed the impact of dams on the distribution of the genetic diversity of Neotropical fish species, and some of them suggest that the genetic structure of fish metapopulations is not affected by damming. However, the effects of dams on the genetic structure of populations may hinge on the biological characteristics of the species, such as homing behavior. Dams prevent some individuals from migrating from their feeding area to their natal spawning area, constraining them to reproduce in the tributaries that are closest to the barrier, and which are already being used as breeding grounds by other subpopulations. In these places, subpopulations may interbreed, thus disrupting the overall genetic structure of the metapopulation. To test this hypothesis, we developed a demogenetic Individual-Based Model that simulates the impact of permeable and impermeable dams on the genetic structure of homing populations, in both the long-term and the short-term. Our results support that genetic homogenization occurs among the subpopulations in the short-term, especially near the dam. The impact of a dam on the genetic structure is also detectable in the long-term (100 generations after the addition of the dam) when the dam is permeable (symmetrical or asymmetrical). However, when the barrier is not permeable, the genetic differentiation among the subpopulations is reestablished in the long-term. Our results suggest that conservation programs should be developed to avoid/mitigate genetic homogenization of populations of fish that display homing behavior in the short-term, and to reestablish the pre-dam genetic structure of these populations in the long-term. [ABSTRACT FROM AUTHOR]

In Structural Health Monitoring, non-harmonic periodic hidden covariate typically arises when an observed structural response depends on unobserved external effects such as temperature or loading. This paper addresses this challenge by proposing a new extension to Bayesian Dynamic Linear Models (BDLMs) for handling situations where non-harmonic periodic hidden covariates may influence the observed responses of structures. The potential of the new approach is illustrated on the data recorded on a dam in Canada. A model employing the proposed approach is compared to another that only uses a superposition of harmonic hidden components available from the existing BDLMs. The comparative study shows that the proposed approach succeeds in estimating hidden covariates and has a better predictive performance than the existing method using a superposition of harmonic hidden components. [ABSTRACT FROM AUTHOR]

A good monitoring method is vital for understanding the sources of a water reservoir leakage and planning for effective restoring. Here we present a combination of several tracers ( 222 Rn, oxygen and hydrogen isotopes, anions and temperature) for identification of water leakage sources in the Pushihe pumped storage power station which is in the Liaoning province, China. The results show an average 222 Rn activity of 6843 Bq/m 3 in the leakage water, 3034 Bq/m 3 in the reservoir water, and 41,759 Bq/m 3 in the groundwater. Considering that 222 Rn activity in surface water is typically less than 5000 Bq/m 3 , the low level average 222 Rn activity in the leakage water suggests the reservoir water as the main source of water. Results of the oxygen and hydrogen isotopes show comparable ranges and values in the reservoir and the leakage water samples. However, important contribution of the groundwater (up to 36%) was present in some samples from the bottom and upper parts of the underground powerhouse, while the leakage water from some other parts indicate the reservoir water as the dominant source. The isotopic finding suggests that the reservoir water is the main source of the leakage water which is confirmed by the analysis of anions (nitrate, sulfate, and chloride) in the water samples. The combination of these tracer methods for studying dam water leakage improves the accuracy of identifying the source of leaks and provide a scientific reference for engineering solutions to ensure the dam safety. [ABSTRACT FROM AUTHOR]

Metals in river sediments from a semi-arid Mediterranean basin were investigated from upstream to downstream during contrasting hydrological conditions in 2014 and 2015. The level and origin of the contamination were evaluated using several geochemical and isotopic indicators. Elements were grouped by their level of contamination: high (Pb > Cd > Zn > Cu) and low (Al, Fe, Cr, Co, Ni). Multiple local sources of contamination were identified (industrial, agricultural and domestic waste), as well as very specific ones (gasoline station) and diffuse pollution from atmospheric deposition (gasoline, ores, aerosols). During storm events, the upstream dams can either be secondary sources of contamination or dilutors through particles derived from natural erosion. The contamination was slowed downstream due to the river geomorphology, but eventually washed into the Mediterranean Sea by intense storm events. Naturally derived elements (Co, Ni, Cr, As) were associated with Al, Fe and Mn oxides or clays, and anthropogenic originated metals with phosphorus (Cd and Zn), sulphur (Cu) and POC (Pb enrichment). Cadmium and Pb were the most available metals upstream and at the outlet, but their availability was not strictly related to their degree of contamination. These conclusions could be drawn thanks to an approach by multiple indicators. [ABSTRACT FROM AUTHOR]

Abstract: The Mejerda River is the one of the major rivers in Tunisia and several studies dealt with the importance of this river in terms of ecology, geochemistry and sociology. However, the sedimentary contributions to the coastal zone from the Mejerda River were poorly observed, and we did not find any continuous monitoring. The main objective of this work is to assess the impact of reduction on sediment transport from the upper basins to the coastal area, after the construction of large dams which may have strong and long-lasting effects on coastal geomorphology and ecosystems. In this paper, a paleo-hydrological approach was applied through the study of sediment cores sampled in the low valley meander on alluvial terrace. We attempt to emphasize, through this approach, the reduction in sediment loads to the sea (Gulf of Tunis) due to the construction of dams on the Mejerda River and to changes in climate conditions. Three cores (C1, C3, C5) were sampled in the lower part of the Mejerda near the hydrometric station of Jdaida with different depths (0.9 m, 1.2 m and 3.0 m) and in different dates (2014–2015). Visible successions of sedimentary layers corresponding to the deposits of successive flood events were identified and the history of the sedimentary contributions to the Mejerda was reconstructed. The thickest layers of sedimentary deposits were related to the exceptional events. They are mainly concentrated on the lower part of the core and are predominantly composed of sands. Since the construction of the Sidi Salem dam in 1981, all of the cores C1, C3 and specially C5 presented mostly a succession of small layers of fine material (silt or clay) without any sand deposits in the downstream River bed. In C5, 18 individual slackwater flood units were identified. A strong decrease in the accumulation rate of sediment was observed based on the length of the flood units and the number of years between flood events. A lower sedimentation rate is observed between 1982 and 2015 of about 2.3 cm/year, while it was much more important between 1963 and 1981 of about 4.75 cm/year, and around 10 cm/year between 1950 and 1962. The statistical study of precipitation indicated three climatic successive periods between 1951 and 2009 characterized as wet, dry and intermediate. Thus, the sediment rate was higher before 1974 reaching about 8.47 cm/year for the wet condition, of about 4 cm/year for the dry period between 1974 and 1989, and about 1.6 cm/year in the intermediate period afterward to 2009 that also witnessed the construction of the major dams. [ABSTRACT FROM AUTHOR]

Tamarisk ( Tamarix spp.) is an invasive plant species that is rapidly expanding along arid and semi-arid rivers in the western United States. A biocontrol agent, tamarisk beetle ( Diorhabda carinulata ), was released in 2001 in California, Colorado, Utah, and Texas. In 2009, the tamarisk beetle was found further south than anticipated in the Colorado River ecosystem within the Grand Canyon National Park and Glen Canyon National Recreation Area. Our objectives were to classify tamarisk stands along 412 km of the Colorado River from the Glen Canyon Dam through the Grand Canyon National Park using 2009 aerial, high spatial resolution multispectral imagery, and then quantify tamarisk beetle impacts by comparing the pre-beetle images from 2009 with 2013 post-beetle images. We classified tamarisk presence in 2009 using the Mahalanobis Distance method with a total of 2500 training samples, and assessed the classification accuracy with an independent set of 7858 samples across 49 image quads. A total of 214 ha of tamarisk were detected in 2009 along the Colorado River, where each image quad, on average, included an 8.4 km segment of the river. Tamarisk detection accuracies varied across the 49 image quads, but the combined overall accuracy across the entire study region was 74%. Using the Normalized Difference Vegetation Index (NDVI) from 2009 and 2013 with a region-specific ratio of >1.5 decline between the two image dates (2009NDVI/2013NDVI), we detected tamarisk defoliation due to beetle herbivory. The total beetle-impacted tamarisk area was 32 ha across the study region, where tamarisk defoliation ranged 1–86% at the local levels. Our tamarisk classification can aid long-term efforts to monitor the spread and impact of the beetle along the river and the eventual mortality of tamarisk due to beetle impacts. Identifying areas of tamarisk defoliation is a useful ecological indicator for managers to plan restoration and tamarisk removal efforts. [ABSTRACT FROM AUTHOR]

In the Colorado River downstream of Glen Canyon Dam in the Grand Canyon, USA, controlled floods are used to resupply sediment to, and rebuild, river sandbars that have eroded severely over the past five decades owing to dam-induced changes in river flow and sediment supply. In this study, we examine whether controlled floods, can in turn resupply aeolian sediment to some of the large source-bordering aeolian dunefields (SBDs) along the margins of the river. Using a legacy of high-resolution lidar remote-sensing and meteorological data, we characterize the response of four SBDs (a subset of 117 SBDs and other aeolian-sand-dominated areas in the canyon) during four sediment-laden controlled floods of the Colorado River in 2012, 2013, 2014, and 2016. We find that aeolian sediment resupply unambiguously occurred in 8 of the 16 instances of controlled flooding adjacent to SBDs. Resupply attributed to individual floods varied substantially among sites, and occurred with four, three, one, and zero floods at the four sites, respectively. We infer that the relative success of controlled floods as a regulated-river management tool for resupplying sediment to SBDs is analogous to the frequency of resupply observed for fluvial sandbars in this setting, in that sediment resupply was estimated to have occurred for roughly half of the instances of recent controlled flooding at sandbars monitored separately from this study. We find the methods developed in this, and a companion study, are effective tools to quantify geomorphic changes in sediment storage, along linked fluvial and aeolian pathways of sedimentary systems. [ABSTRACT FROM AUTHOR]

Source-bordering dunefields (SBDs), which are primarily built and maintained with river-derived sediment, are found in many large river valleys and are currently impacted by changes in sediment supply due to climate change, land use changes, and river regulation. Despite their importance, a physically based, applied approach for quantifying the response of SBDs to changes in sediment supply does not exist. To address this knowledge gap, here we develop an approach for quantifying the geomorphic responses to sediment-supply alteration based on the interpretation of dunefield morphodynamics from geomorphic change detection and wind characteristics. We use the approach to test hypotheses about the response of individual dunefields to variability in sediment supply at three SBDs along the Colorado River in Grand Canyon, Arizona, USA during the 11 years between 2002 and 2013 when several river floods rebuilt some river sandbars and channel margin deposits that serve as sediment source areas for the SBDs. We demonstrate that resupply of fluvially sourced aeolian sediment occurred at one of the SBDs, but not at the other two, and attribute this differential response to site-specific variability in geomorphology, wind, and sediment source areas. The approach we present is applied in a companion study to shorter time periods with high-resolution topographic data that bracket individual floods in order to infer the resupply of fluvially sourced aeolian sediment to SBDs by managed river flows. Such an applied methodology could also be useful for measuring sediment connectivity and anthropogenic alterations of connectivity in other coupled fluvial-aeolian environments. [ABSTRACT FROM AUTHOR]

In this investigation, the capacity of citric acid as copper scavenger is analyzed. For the copper scavenger capacity, the formation of the chelate complexes is studied using the Gibbs free energies. The chelates may be formed since the formation reactions are all exergonic. The free radical scavenger ability of chelate complexes is investigated using the single electron transfer mechanism with the Full Electron Donor-Acceptor Map (FEDAM). Different acid-base species of citric acid are also studied as OH inactivating ligands (OIL). The conclusion of this investigation is that metal chelation is viable for citric acid species and also that the formed chelates are efficient OH scavengers. Therefore, it is possible to conclude that citric acid is promising for copper chelation therapy (metal scavenger). These results may be useful for further investigations concerning citric acid and can give ideas about the benefits of citric acid as an additive in food. [ABSTRACT FROM AUTHOR]

Southwest China, as one of the largest continuous karst areas in the world, is a severely eroded region due to its special geological condition. Thus, soil and water conservation measures such as dam construction have been extensively implemented in this region to control sediment delivery. However, it remains unclear how dam construction affects multiscale variability of sediment discharge (SD) and its potentially influential factors in southwest China. To assess this, annual SD, water discharge (WD), precipitation (PT), potential evapotranspiration (PET), and normalized differential vegetation index (NDVI) data from 1955 to 2015 were obtained from two karst watersheds of Liujiang (no large dams) and Hongshui (dam-controlled). These sites shared the similar climatic conditions. The Mann-Kendal test, Wilcoxon rank-sum test, and continuous wavelet transform analysis was used to detect the trends and periodicity in SD, and wavelet coherence analysis were employed to detect the temporal covariance between SD and WD, PT, PET, and NDVI. Results indicated that the multiscale variability of SD was strongly influenced by dam construction. The annual SD showed significant 4-year periodic oscillation in the Liujiang watershed, while no significant cycles were found in the Hongshui watershed. Dam construction exerted substantial influence on the multiscale correlations between SD and its associated factors. The time scales that the NDVI resonated with SD were concentrated on the periodicity of 2- and 3-year in the Liujiang watershed. In contrast, no significant periodicities were observed in the Hongshu watershed. This study yields a greater understanding of SD dynamics, and is helpful for better watershed management in karst areas of southwest China. [ABSTRACT FROM AUTHOR]

Dams are universally constructed to change hydrodynamic forces and impound water in urban rivers, but few efforts have been made to expound the impact of dams on the transport of antibiotics in rivers. In this study, the main object and focus was to elucidate the intercept effect of rubber dam and the gate dam on the sediment-water phase redistribution of eight typical antibiotics along an urban river with the water replenished from wastewater treatment plants (WWTPs). The results show that the eight antibiotics were widely detected in the whole river segment, and the WWTPs were found to be the main sources. Among the eight antibiotics, fluoroquinolones had the highest concentrations in the surface water, while tetracyclines constituted the dominant composition in the sediments. Due to the retention effect, the rubber dam encouraged the enrichment and degradation of the antibiotics in the river. However, the role of gate dams depended mainly on the opening and closing of the sluice gate. For all eight antibiotics, each dam or WWTP exhibited a generally consistent impact on the changes (e.g., an increase or decrease) of the sediment-water partitioning coefficients, although obvious differences existed between effect degree. Moreover, the changes in the coefficients caused by the rubber dam were completely opposite to those affected by gate dams. Contrary to the other six antibiotics, the two sulfonamides showed significant relationships with the dissolved organic matter in the surface water but had no significant relationships with the organic matter in the sediments. [ABSTRACT FROM AUTHOR]

In a hydroelectric reservoir, sediments are subject to remobilization events, water-level fluctuations and physicochemical changes. Depending on their associated metallic content, surficial oxic to suboxic sediments could constitute a major source of metals. To identify the key parameters that control metallic elements in terms of their mobility and sensitivity to reservoir management, sediments were subject to resuspension and drying/wetting cycle experiments over a wide range of pH values, solid/liquid ratios (S/L) and redox (Eh) conditions. During these tests, special attention was also paid to the influence of pretreatments on samples, i.e., drying, aeration and the leachate composition (ultrapure water vs. natural water); on the preservation of the sediment characteristics; and especially on metallic element release. The results of this study show that the pH, S/L ratio and Eh parameters are key variables in metal solubilization; the pH influences metal mobility primarily through sorption-desorption phenomena as well as the dissolution of metallic-bearing phases, the S/L ratio modifies the sorption-desorption equilibria, and the Eh primarily affects the reducible sensitive phases and associated metallic elements through dissolution-precipitation processes. Under environmental conditions, evolution of these parameters can lead to a > 20% solubilization of the most mobile elements, i.e., As and Cd. These results are influenced by the sample pretreatment and experimental conditions. In fact, even if the solubilization patterns show no significant differences between dry and wet sediment depending on the physicochemical conditions, the magnitude of their release is significantly affected. Drying pretreatment induces changes in metal speciation, notably altering the distribution of the most weakly bound elements; there is almost half the amount of metallic elements associated with the exchangeable fraction in dry compared to wet sediments. The solubilization percentages were higher in the ultrapure phase than in reservoir water primarily due to the low pH, which influenced the sorption equilibria. [ABSTRACT FROM AUTHOR]

Hydrological variability over seasonal and multi-annual timescales strongly shapes the ecological structure and functioning of floodplain ecosystems. The current IPCC climate scenario foresees an increase in the frequency of extreme events. This, in conjunction with other anthropogenic disturbances ( e.g. , river regulation or land-use changes) poses a serious threat to the natural functioning of these ecosystems. In this study we aimed to i) evaluate the long-term variability of the flooded area of the third largest floodplain lake in the Brazilian Pantanal using remote sensing techniques, and ii) analyze the possible factors influencing this variability. Changes in open-water and riparian floodplain-wetland vegetation areas were mapped by applying an ad hoc -developed remote-sensing method (including a newly developed normalized water index, NWI) to 221 Landsat-Thematic Mapper (TM)/Enhanced Thematic Mapper Plus (ETM +) images, acquired between 1984 and 2011. Added to the lake's natural swing between riparian floodplain-wetland vegetation expansion and retraction, our analyses revealed large interannual changes, grouped into three main periods within the studied time interval. Moreover, our results indicate that this floodplain-lake system is losing open-water area, paired with an increase in riparian floodplain-wetland vegetation. The system's long-term dynamics are not all climate related, but are the result of a combination of drivers. The start of the Manso dam's operation upstream of the studied system, and the subsequent river regulation because of the dam operation, coupled with climatic oscillation appear to be responsible for the observed changes. However, other factors which were not considered in this study might also be important in this process and contributing to the reduction of the system's resilience to droughts ( e.g ., land-use changes). This study illustrates the serious conservation risks that the Pantanal faces in the near future, given the current climate-change scenario and the accumulation of dam building projects in this region. [ABSTRACT FROM AUTHOR]