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We evaluated the HIV-1 DNA reservoir in peripheral blood mononuclear cells (PBMC) and cerebrospinal fluid (CSF) in people with HIV (PWH) and associations to cognitive dysfunction. Using the intact proviral DNA assay (IPDA), an emerging technique to identify provirus that may be the source of viral rebound, we assessed HIV DNA in CSF and PBMC in PWH regardless of antiretroviral therapy (ART). CSF was used as a sampling surrogate for the central nervous system (CNS) as opposed to tissue. IDPA results (3' defective, 5' defective, and intact HIV DNA) were analyzed by compartment (Wilcoxon signed rank; matched and unmatched pairs). Cognitive performance, measured via a battery of nine neuropsychological (NP) tests, were analyzed for correlation to HIV DNA (Spearman's rho). 11 CSF and 8 PBMC samples from PWH were evaluated both unmatched and matched. Total CSF HIV DNA was detectable in all participants and was significantly higher than in matched PBMCs (p ​= ​0.0039). Intact CSF HIV DNA was detected in 7/11 participants and correlated closely with those in PBMCs but tended to be higher in CSF than in PBMC. CSF HIV DNA did not correlate with global NP performance, but higher values did correlate with worse executive function (p ​= ​0.0440). Intact HIV DNA is frequently present in the CSF of PWH regardless of ART. This further supports the presence of an HIV CNS reservoir and provides a method to study CNS reservoirs during HIV cure studies. Larger studies are needed to evaluate relationships with CNS clinical outcomes.

The deformation evolution of reservoir slope shows obvious time-sensitive characteristics. Based on the gray system new information priority theory, this paper introduced an equidistant NOGM (1,1) model based on new initial condition optimization to strengthen the latest time-sensitive factors on reservoir slope, thus, the influence proportion of the latest environmental variables on slope deformation was increased. It used the artificial jellyfish search algorithm to intelligently optimize the relevant model parameters and build the AJSO-NOGM (1, 1) model for reservoir slope deformation prediction. The example analysis shows that the method has higher prediction accuracy and well reflects the deformation trend of reservoir slope compared with the traditional gray system GM (1,1) model. [ABSTRACT FROM AUTHOR]

Introduction: The main obstacle to achieving an HIV-1 cure is the proviral reservoir. To promote equity in HIV cure strategies, it is crucial to study the viral reservoir of the predominant HIV-1 subtype C in both women and men. Therefore, we investigated the dynamics of the (intact) viral reservoir in relation to plasma viral load (VL), CD4+ T cell count, and immune activation before and during 96 weeks of successful antiretroviral therapy (ART). Methods: Eighty-two participants (62% female) newly initiating ART in a rural clinic in South Africa were included in the study. Blood samples were collected at baseline, week 48, and week 96, and CD4 count was determined. Plasma was used for VL and immune marker analyses, while isolated peripheral blood mononuclear cells (PBMCs) were used for the quantification of cellular multiple spliced HIV-1 RNA (msRNA) and the intact proviral DNA assay. For the longitudinal analyses on ART, we selected only those participants who durably suppressed their VL to <200 copies/mL during 48 (n=65) and/or 96 (n=60) weeks of treatment. Results: At ART initiation, the median CD4 count was 234 cells/mm3 and VL was 68,897 copies/mL. Interestingly, at baseline the number of defective proviruses was significantly correlated with VL (p<0.0001), msRNA (p<0.0001), CD4 count (p=0.0008), CXCL10 (p=0.0003) and TNF-α (p=0.0394). During successful ART, a significant decrease of both the intact and defective proviral reservoir was observed (p<0.0001). The decrease of the intact proviral reservoir was more profound compared to the defective fraction after 96 weeks of therapy. In addition, a significant decrease in cellular msRNA and IL-6, IL-7, TNF-α, sCD14, sCD163, CCL2, CXCL10, and CRP was detected. Discussion: This study underscores the significant relationship observed prior to therapy initiation between the number of defective proviruses, viral transcription/production and their association with immune response indicators such as CD4 count, CXCL10, and TNF-α. Furthermore, the observation of a less pronounced decrease of the defective proviral DNA highlights the importance of addressing both intact and defective proviruses in therapeutic strategies to enhance clinical outcomes for people with HIV-1. Together, these findings suggest a significant role of the defective proviruses in HIV-related disease progression. [ABSTRACT FROM AUTHOR]

ABSTRACT Aims Methods and Results Conclusions Leishmaniasis is an endemic disease in several regions of Brazil, a tropical country that presents specific environmental conditions that contribute to the development of phlebotomine vectors. This study aimed to detect Leishmania species in naturally infected bats from 17 municipalities in the São Paulo state.Spleen and liver samples from 203 bats were analysed by real‐time PCR and confirmed by conventional PCR followed by gene sequencing. Leishmania DNA was amplified by real‐time PCR in 6.4% of the bats and by conventional PCR followed by sequencing in 3.4% of the bats. Positive samples were characterised and included in GenBank. Leishmania species were confirmed in M. molossus, M. nigricans and E. glaucinus bats. Leishmania (Leishmania) amazonensis and L. infantum (syn. L. chagasi) were identified. This is the first detection of Leishmania spp. in bats in the studied areas. All the positive bats came from urban areas. Insectivorous bats were statistically more positive. There was similarity between our sequences and those of a human isolate and a phlebotomine from the region.This result points to bats as important possible reservoir of Leishmania in Brazil and guides the country's health authorities towards epidemiological surveillance, control and prevention actions in endemic areas. [ABSTRACT FROM AUTHOR]

The composition and concentration of dissolved organic matter (DOM) in freshwater ecosystems are influenced by the abundance and diversity of phytoplankton, which are, in turn, affected by nutrient availability. The interactions among DOM, phytoplankton, and nutrients are not fully understood, particularly regarding dissolved Si (DSi), a required nutrient for diatoms but generally not for other major phytoplankton groups. In this study, we sought to characterize the relationships among the optical properties of DOM, phytoplankton abundance (as chlorophyll a) and functional group relative biovolume, and nutrient concentrations (dissolved NO3–, soluble reactive P, dissolved organic C, and DSi) in a large reservoir in south-central Indiana, USA, a site representative of dimictic, mesotrophic reservoirs in temperate climates. We found that DOM composition varied throughout the summer growing season, and the variation was correlated to changes in phytoplankton abundance. We also found strong relationships between diatom biovolume, DSi concentrations, and the protein fractions of DOM, which indicates that the availability of DSi may influence the composition of DOM, likely mediated through the productivity of diatoms. This proposed relationship suggests changes in DSi availability could indirectly elicit responses in the composition, processing, and fate of DOM in freshwater systems. Describing these relationships in a reservoir is of particular interest given that dams drive changes in water retention time, light availability, and biogeochemical processes that affect DOM production and transformations. This novel coupling of C and Si cycling highlights the need to better understand controls on the sources and fates of C in reservoirs, particularly given the increase in dam construction across much of the world. [ABSTRACT FROM AUTHOR]

Investigating the origin of authigenic quartz is crucial for elucidating shale sedimentary and diagenetic processes, thereby enhancing shale oil exploration. Within the Middle Eocene Shahejie Formation of the Jiyang Depression, lacustrine shale serves as a significant reservoir for shale oil, characterized by its abundant authigenic quartz. In this study, scanning electron microscopic (SEM) imaging and transmission electron microscopic (TEM) imaging, in-situ or bulk elemental data, porosity data, and oil saturation data were used to clarify the origin of authigenic quartz and its effect on pore and oil content of shale. Mineral and in-situ elemental evidence shows that the authigenic quartz originated in saline early diagenetic pore water. The conditions conducive to the formation of authigenic quartz in the study area closely resemble those observed in Coorong Lagoon, suggesting potential implications for understanding the origin of the investigated authigenic quartz. The study suggests that the presence of saline lake water and early diagenetic dissolution of detrital quartz are significant contributors to the dissolved silicon content, promoting the origin of authigenic quartz in the study area. Furthermore, the acidic environment, resulting from the accumulation of humic acid, facilitates the precipitation of precursors to authigenic quartz. Microscopic imaging combined with porosity and oil saturation data shows that this authigenic quartz increases intercrystalline pores in the range of 100–1000 nm and oil saturation. These results provide insights into the understanding of the diagenetic process in saline lacustrine shale and the factors controlling shale pore evolution. [ABSTRACT FROM AUTHOR]

The Triassic-Jurassic successions of the Sulaiman Fold-Thrust Belt, Pakistan, are predominantly composed of limestone with minor proportions of shale, marl, and sandstone, accumulated at the northwestern passive margin of the Indian Plate within the Palaeo-Tethys. The current work is an outcome of field observations, thin-section petrographic studies, and scanning electron microscopy (SEM), aiming to reconstruct the palaeoenvironments and diagenetic pathways. Facies analysis and microscopic descriptions revealed sixteen microfacies, including mud-supported microfacies (mudstone and wackestone), grain-supported microfacies (packstone and grainstone) and calcisiltite. The Triassic succession includes calcisiltite and radiolarite, deposited below the CCD. Carbonates of the study area reflect both early-stage diagenesis (micrite envelopes, syntaxial rim cement, drusy mosaic calcite cement, and microbial micritization) - and late-stage diagenesis (chemical compaction, partial mechanical compaction, filling of fractures, and stylolites). Specific types of cement including dog tooth, syntaxial overgrowths, circumgranular, granular, radiaxial acicular and drusy mosaic calcite cements, indicate an early diagenetic stage of the marine phreatic zone. The Triassic-Jurassic carbonates have been affected by various diagenetic processes, which include cementation, compaction, dissolution, replacement and de-dolomitization, indicating primarily alteration by marine phreatic diagenesis, later burial diagenetic processes and mechanical breakdown of the rocks subsequently controlled by tectonics. Sea level changes, punctuated by tectonics and the paleogeographic evolution of the Indian Plate, controlled these depositional and diagenetic changes. [ABSTRACT FROM AUTHOR]

Vibrio cholerae is the causative agent of cholera, an acute diarrheal disease that spreads locally and globally in epidemics and pandemics. Although it was discovered that fish harbor V. cholerae strains in their intestines, most investigations revealed non-toxic V. cholerae serogroups in fish. Due to the rarity of toxigenic V. cholerae serogroups, it is difficult to cultivate these strains from environmental samples. Hence, here we aimed to uncover evidence of the occurrence of toxigenic V. cholerae in the intestines and spleens of various fish species. By using molecular detection tools, we show that V. cholerae O1 and strains positive for the cholera toxin inhabit both healthy and diseased fish intestines and spleens, suggesting that fish may serve as intermediate vectors of toxigenic V. cholerae. No significant differences were found between the abundance of toxigenic V. cholerae (either O1 or cholera toxin positive strains) in the healthy and the diseased fish intestines or spleens. In conclusion, a variety of fish species may serve as potential vectors and reservoirs of toxigenic V. cholerae as they form a link between the other reservoirs of V. cholerae (chironomids, copepods, and waterbirds). Similarly, they may aid in the spread of this bacterium between water bodies. [ABSTRACT FROM AUTHOR]

Reservoirs influence the global climate by exchanging greenhouse gases (GHGs) of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) with the atmosphere. Few studies, however, quantify emissions of all three GHGs from reservoirs, particularly in permafrost‐affected mountain regions where ecosystems are highly vulnerable to climate change. This study presents three‐year direct measurements of CO2, CH4, and N2O concentrations and fluxes upstream, within, and downstream from two reservoirs draining permafrost catchments on the Qinghai‐Tibet Plateau, including periods of reservoir drawdown. Comparing GHG fluxes across space and time exhibits a general pattern of lower fluxes at the two reservoirs relative to up‐ and downstream channels. Ebullitive fluxes contributed to 36.7% and 9.4% of total CH4 and N2O fluxes, respectively. CO2 has no response to drawdown, but CH4 and N2O display synchronous drawdown‐associated increase within the reservoir, constituting 57.5% and 32.8% of the annual reservoir emissions in just 2 months, respectively. Riverine emissions from up‐ and downstream channels accounted for an outsized fraction (55.5% for CH4, 17.3% for CO2 and 16.5% for N2O) of the system‐wide GHG budget. Compared with global reservoirs, the two reservoirs have high CO2 and N2O but low CH4 fluxes in CO2 equivalents. Upscaling shows that the two reservoirs emit the same magnitude of carbon as thermokarst lakes, and four times higher N2O than Finnish lakes on an areal basis. This article shows that alpine reservoirs draining permafrost catchments are unrecognized atmospheric sources in current reservoir GHG inventories, but also emphasizes the importance of system‐wide emissions when assessing total GHG evasion from reservoir systems. Key Points: Unlike global reservoirs, the two reservoirs draining permafrost catchments on the Qinghai‐Tibet Plateau have both high CO2 and N2O but low CH4 fluxes in terms of CO2 equivalentsThe two reservoirs emit the same magnitude of carbon (CO2 + CH4) as thermokarst lakes on an areal basisWater‐level drawdown and up‐ and downstream channel emissions play a pivotal role in system‐wide greenhouse gases emissions, marking the first discovery of increased N2O emissions during drawdown [ABSTRACT FROM AUTHOR]

This work principally involves the petrophysical evaluation and the determination of hydrocarbon saturation of potential reservoirs in the Rio del Rey basin. Petrel 2017 software was used to interpret the obtained data well logs and seismic. Illustrator CS was used to find tune and arrange the maps and figures. From the studies, four reservoirs (S1A1, S1A2, S1A3 and RB) in total were successfully detected from two target wells: S-C1 and S-FB. Porosity, permeability and water saturation ranged between 17 to 22%, 149 to 193.5 mD and 60 to 100%, respectively. Good reservoirs were discovered based on the petrophysical studies at multiple zones, but only two were of interest to this work. The most prolific zones are those with less than 80% saturation of water and porosity of 17% and 22%. The remaining zones had the same porosity and permeability range but were not considered prolific zones due to high shale volume and more than 80% water saturation. Seismic interpretation revealed the presence of seven listric faults, two major faults (F9 and F19 trending in the NE-SW and E-W direction, respectively) and five minor faults (F7, and F2, and F6 which appear in the two wells). Faults F9, F2 and F6 trend in the same direction as the major faults: Eastern to Western. Four major horizons (S1A1, S1A2, S1A3, RB) were identified in well S-C1, and only one of these major horizons was identified in well S-FB (S1A3). All these horizons correspond to the five reservoir tops to be studied in the two target wells. Rollover anticlinal structures and fault closures between the listric faults were identified. All three types of environments of deposition of sediments were found in the reservoirs: progradational (sediment shift landward), aggradational (deposition far away from shore) and retrogradational (sediment shift seaward) sequences. Rollover anticline or four-way structural closure constitutes the main mechanism for trap formation. STOOIP of the reservoirs have been determined with S1A3 and RB zone being more prolific. The STOOIP of S1A3 is given by 11.2 MMbbls high case, 8.5 MMbbls base case and 7.4 MMbbls low case, while the STOOIP of RB is given by 8.6 MMbbls for the base case and 10.8 MMbbls for the high case. [ABSTRACT FROM AUTHOR]

The article defines the morphometric, hydrochemical, and hydrobiological parameters of the Ust-Kamenogorsk reservoir, located on the territory of Ablaketka and the Bukhtarma reservoir, formed in the zone of narrowing of the mountain valley (1960), 12 km below the confluence of the Bukhtarma River with the Irtysh River. When determining deviations in indicators of the reservoirs, data from gauging stations have been taken into account. The purpose of the article is to conduct a comprehensive assessment of the current state of two large reservoirs in the East Kazakhstan region during the specified time period. The novelty of this topic lies in its comprehensive approach to assessing various aspects of the reservoirs' condition in a specific region over a defined period. This approach enables the identification of current trends and issues and facilitates the proposal of practical measures to address them and enhance water resource management. As a result of this research work, after analyzing changes in indicators, the condition of the reservoirs was determined. During the research work, according to the results of hydrochemical studies, the Bukhtarma reservoir is favorable for the habitat of aquatic organisms, and in the Ust-Kamenogorsk reservoir, a positive change in hydrochemical parameters has been noted compared with 2020. In addition, after analyzing the research indicators, it was proposed to form specially protected areas in the Bukhtarma reservoir, suitable for use in connection with the distribution of valuable fish listed in the Red Book of the Republic of Kazakhstan. When demonstrating the location of gauging stations, methods of remote sensing of the earth and the method of geoinformation mapping were used. [ABSTRACT FROM AUTHOR]

The intrusion of non-native species into freshwater ecosystems can lead to rapid shifts in fish community dynamics, posing significant threats to biodiversity and ecological stability. In this study, we examined the changes in the fish community within the Kerkini Reservoir, a Ramsar Site in Greece, influenced by the establishment of invasive fish species. Through standardized seasonal surveys conducted in 2007–2008 and 2023, we assessed changes in fish species composition, abundance, and functional traits. Our findings revealed a shift in dominance, with invasive species such as Gymnocephalus cernua emerging as key players in the reservoir's fish fauna. Moreover, high numbers of fish specimens and biomass were recorded, highlighting the reservoir's high productivity. However, concerns arise regarding the ecological impacts of invasive species, particularly G. cernua, which exhibits traits associated with ecological disruption and competition with native species. A shift towards the dominance of species with shorter lifespans, smaller sizes and lower trophic levels was observed. In addition, the observed decline in native species abundance, coupled with poor ecological quality assessments, underscores the need for proactive management measures to preserve ecosystem integrity. This study contributes valuable insights into the ecological dynamics of a system considered a biodiversity hotspot. It also highlights the proliferation of invasive fish species as a primary driver and underscores the importance of ongoing monitoring and conservation efforts. However, future research is needed, focusing on further understanding the long-term effects of invasive species establishment and their implications for native fish populations and ecosystem functioning. [ABSTRACT FROM AUTHOR]

Methods for determining evaporation from water and soil surface are considered. Monthly evaporation values were calculated for experimental grounds in the Crimean Peninsula based on measurement data from automatic meteorological complexes over 2022–2023. The estimates of evaporation from reservoir surfaces were compared with the evaporation values for individual months obtained using ground-based evaporators. Calculations by V.I. Moklyak's formula showed the best agreement with the results derived from field observations of evaporation. The relative error of evaporation estimate by the recommended method is 15%. An estimate of the monthly evaporation from soil, based on calculation methods with the use of dependences on various meteorological factors is given. [ABSTRACT FROM AUTHOR]

When reservoirs are constructed on rivers, river velocity decreases and the river system gradually evolves into a reservoir system. This phenomenon is particularly pronounced in the case of megareservoirs. Previous studies on this problem mostly relied on physical models, analyzing changes in water temperature. However, traditional physical process models are limited by data availability on hydrology, meteorology, and topography. Conversely, data-driven models offer the advantages of a simple structure, ability to use remote sensing data as primary data, easy acquisition, and efficiency in parameter tuning. This study constructed a hybrid artificial neural network data-driven water temperature model using a mutual information screening model to drive factors and dividing the dataset using the hold-out method. Taking the Xiaowan Reservoir as an example, the vertical distribution of water temperature across 20 layers was simulated and predicted. The results are as follows: (1) The Hybrid Artificial Neural Network (H-ANN) model enhanced the accuracy of simulating vertical water temperature in the reservoir by taking into account the correlation between water temperatures at different depths, effectively overcoming the challenges of traditional physical models (acquisition of experimental data and difficulties in model parameter tuning). (2) The water temperature simulated using the H-ANN model showed good agreement with observed water temperature in the Xiaowan Reservoir. The average Nash-Sutcliffe efficiency (NSE), correlation coefficient (r), root mean square error (RMSE), mean squared error (MSE), and mean absolute error (MAE) for water temperature in the 1–200 m layer were 0.94, 0.98, 0.23°C, 0.1°C, and 0.13°C, respectively, during the training period, and 0.9, 0.96, 0.32°C, 0.16°C, and 0.19°C, respectively, during the testing period. Overall, the model showed a high degree of conformity between simulated and observed series, indicating the suitability of the mutual information-based and concatenated multilayer ANN data-driven model for simulating vertical water temperature. (3) The Xiaowan Reservoir is a typical stratified reservoir with evident seasonal thermal stratification, where the epilimnion ranges from 1 to 15 m, the metalimnion ranges from 15 to 80 m, and the hypolimnion lies below 80 m. [ABSTRACT FROM AUTHOR]

Acquired immune deficiency syndrome is an infectious disease with high mortality caused by human immunodeficiency virus (HIV). Even after antiretroviral therapy, the virus reservoir formed by the provirus integrated in the host genome can evade host immune surveillance and clearance. The existing methods of HIV reservoir detection mainly include cell culture induced virus growth assay in vitro and direct detection of the provirus genome based on PCR technology. Understanding and measuring accurately of HIV reservoir can provide reliable technical basis for HIV treatment research. This article summarizes and analyzes various detection methods of HIV reservoirs in recent years and their advantages and disadvantages, in order to select the suitable method for different detection objects of HIV reservior, and give appropriate suggestions, to provide technical support and theoretical guidance for further research on acquired immune deficiency syndrome. [ABSTRACT FROM AUTHOR]

Despite its effectiveness in controlling plasma viremia, antiretroviral therapy (ART) cannot target proviral DNA, which remains an obstacle to HIV-1 eradication. When treatment is interrupted, the reservoirs can act as a source of viral rebound, highlighting the value of proviral DNA as an additional source of information on an individual's overall resistance burden. In cases where the viral load is too low for successful HIV-1 RNA genotyping, HIV-1 DNA can help identify resistance mutations in treated individuals. The absence of treatment history, the need to adjust ART despite undetectable viremia, or the presence of LLV further support the use of genotypic resistance tests (GRTs) on HIV-1 DNA. Conventionally, GRTs have been achieved through Sanger sequencing, but the advances in NGS are leading to an increase in its use, allowing the detection of minority variants present in less than 20% of the viral population. The clinical significance of these mutations remains under debate, with interpretations varying based on context. Additionally, proviral DNA is subject to APOBEC3-induced hypermutation, which can lead to defective, nonviable viral genomes, a factor that must be considered when performing GRTs on HIV-1 DNA. [ABSTRACT FROM AUTHOR]

Background The 3-piece inflatable penile prosthesis (IPP) is the most widely used device for erectile dysfunction refractory to medications, containing a reservoir inserted into the retropubic space (RPS) or an alternative/ectopic space (AES). Indications for removal of the reservoir include malfunction, malposition, or infection. In revision cases without infection, reservoir removal is sometimes optional. Aim We reviewed outcomes and complications related to reservoir removal from a large multi-institutional series. Methods We retrospectively reviewed databases at 6 institutions over 7 years. Patients with artificial urethral sphincter, urethral sling, or mini-jupette were excluded. Outcomes Outcomes and complications related to IPP reservoir removal were analyzed. Data were collected, but only reservoir-related complications at surgery were included. Data were compared between the RPS and AES cohorts to evaluate differences with a χ2 test, with significance at P <.05. Results Of 215 cases, there were 172 RPS and 43 AES reservoirs. The mean patient age was 65.3 years. An overall 131 procedures were due to malfunction and 49 to malposition of an IPP component; 35 were secondary to infection. Among those retained (n = 44), reasons included reuse, avoiding surrounding structure damage, and difficult dissection. Among those removed (n = 171), 15 required a counterincision. To determine the statistical difference between those removed from the RPS and an AES, the χ2 test result was P =.00059, indicating a significant difference in the need for a counterincision between the groups. Complications included bladder perforation (n = 1) in the RPS group and an avulsion of the epigastric vessels requiring abdominal exploration (n = 1) in the AES group. To determine the statistical difference between RPS and AES complications, the χ2 test result was P =.365, indicating no significant difference between the groups. Strengths and Limitations Strengths include being a multi-institutional study with high-volume skilled implanters. Limitations include being a retrospective review, with implanters exclusively performing penoscrotal incisions and not utilizing an infrapubic approach. Last, there was a lack of long-term follow-up with these patients. Conclusions Removal of an IPP reservoir remains safe, with few intraoperative complications. Surgeons should be aware of the inferior epigastric vessels during removal in an AES or be willing to perform a counterincision to avoid injury to surrounding structures. Surgeons should also obtain preoperative imaging to identify the specific location of the reservoir and adjacent anatomy. This is the first multi-institutional study reviewing outcomes related to reservoir removal during IPP revision or removal surgery. [ABSTRACT FROM AUTHOR]

This study presents an analysis of the influence of climatic conditions and the operation of a dam reservoir on the occurrence of ice cover and water temperature in two rivers (natural and transformed by reservoir operations) located in the Carpathian Mountains (central Europe). The analyses are based on data obtained from four hydrological and two climatological stations. The Extreme Gradient Boosting (XGBoost) machine learning model was used to quantitatively separate the effects of climate change from the effects arising from the operation of the dam reservoir. An analysis of the effects of reservoir operation on the phase synchronization between air and river water temperatures based on a continuous wavelet transform was also conducted. The analyses showed that there has been an increase in the average air temperature of the study area in November by 1.2 °C per decade (over the period 1984–2016), accompanied by an increase in winter water temperature of 0.3 °C per decade over the same period. As water and air temperatures associated with the river not influenced by the reservoir increased, there was a simultaneous reduction in the duration of ice cover, reaching nine days per decade. The river influenced by the dam reservoir showed a 1.05 °C increase in winter water temperature from the period 1994–2007 to the period 1981–1994, for which the operation of the reservoir was 65% responsible and climatic conditions were 35% responsible. As a result of the reservoir operation, the synchronization of air and water temperatures was disrupted. Increasing water temperatures resulted in a reduction in the average annual number of days with ice cover (by 27.3 days), for which the operation of the dam reservoir was 77.5% responsible, while climatic conditions were 22.5% responsible. [ABSTRACT FROM AUTHOR]

The contamination of the aquatic ecosystem with heavy metals has become a rising global concern due to their possible adverse health effects on human beings and the environment. Hence, the objective of this paper was to evaluate the levels of Fe, Cu, Cd, Zn, Pb, As, and Cr and their potential effects on water, sediment, and water hyacinth plants in Opa Reservoir, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria using Atomic Absorption Spectrometry. The concentration of heavy metals in the hyacinth samples varied from 0.002 ± 0.000ppm to 0.5 ± 0.000ppm exceeding permissible limit except for Cu, Zn, and Fe. The metals in water samples ranged between 0.003 ± 0.001ppm to 0.5 ± 0.000ppm also surpassing the concentration limit established by WHO with only Cu, Zn, and Fe having lower concentrations. Sediment samples revealed a high concentration, varying from 0.005 ± 0.000ppm to 4.150 ± 0.002ppm. The values obtained were far above the permissible values set by WHO with only Zn, Fe, and As having lower concentrations. The contamination factor analysis indicated generally low contamination factor with the exception of Fe and Cr which showed moderate contamination. Although the pollution load index and geo accumulation index revealed that all metals were within the range of unpolluted geo-accumulation index, enrichment factor indicated varying degrees of contamination. While some metals exhibited depletion to minimal enrichment, others revealed significant or even extremely high enrichment pollution index. Considering the pollution status of the Opa reservoir, it is therefore recommended that regular monitoring of the reservoir be put in place to ensure the safety of human and aquatic ecosystems in general. [ABSTRACT FROM AUTHOR]

Tilapia is an important fishing resource in economic terms for continental ecosystems such as dam reservoirs and lagoons. In Nayarit, the Aguamilpa Dam reservoir contributes around 50 % of the tilapia production in the state. However, despite the social and economic importance of the resource, there are few studies on it in this reservoir, and it is still unknown with certainty which species are found in the reservoir. This work is the first report for the Aguamilpa reservoir, where geometric morphometrics was used as a tool for the identification of tilapia species. The pharyngeal plate of 230 organisms was used for the geometric morphometrics analysis. According to this study, the existence of three species of the genus Oreochromis (O. aureus, O. niloticus and Oreochromis mossambicus) is confirmed; according to the analysis of canonical variables, the three species were correctly discriminated. This allows us to conclude that the use of geometric morphometrics in the pharyngeal plate is a useful structure for the identification of species in the reservoir. [ABSTRACT FROM AUTHOR]

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Copyright of Petroleum Geology & Experiment is the property of Petroleum Geology & Experiment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Monitoring and analyzing reservoir water quality are crucial for ecological and environmental strategies. This study examines the differences between the water quality index (WQI) of Indonesia (WQI-INA), Malaysia (DOE-Malaysia), Oregon (WQI-Oregon), and Italy (PI-Prati), considering the tropical climate of Indonesia and Malaysia, and contrasting with the temperate climate of Oregon and the Mediterranean climate of Italy. Using data from the Sutami Reservoir in Indonesia from 2015 to 2021, the study assesses water quality parameters such as BOD, COD, DO, NH3, NO3, total suspended solids, total phosphorus (TP), and pH at various depths (0.3, 5, and 10 meters) across three sites (upstream, midstream, down-stream). The results show varied classifications: WQI-INA rated the reservoir as "pretty good," WQI-Oregon as "poor," and both DOE-Malaysia and PI-Prati as "slightly polluted." Spatial analysis of vertical distribution revealed "slightly polluted" (WQI-INA), "moderately polluted" (WQI-Oregon and PI-Prati), and "heavily polluted" (DOE-Malaysia). These discrepancies arise from differences in local environmental standards, regulatory requirements, and specific water quality concerns included in each index. The Sutami Reservoir water quality status was declared using WQI-INA, however, other methods were employed to simulate the worst-case scenarios and inform preventive actions. The Sutami Reservoir hyper-eutrophic conditions indicate a pollution load capacity of 65.22 tons per year. Critical parameters such as pH and TP highlight significant water quality and pollution issues. Recommendations for water quality treatment under heavy pollution conditions include applying 12.09-120.87 tons of lime, using 78.75-393.75 kg of chemical buffers, oxygen diffusion, controlling riparian vegetation over 2.37-23.7 hectares, dredging 37,100 m3 of sediment per year, and reducing nutrient sources through community involvement. [ABSTRACT FROM AUTHOR]

This study explores the in vitro effects of cyanotoxins from the methanolic extract of the cyanobacteria Aphanizomenon flos-aquae and Microcystis aeruginosa on human blood cells, with samples drawn from the Gruža reservoir in Serbia. These cyanobacteria, which made up 98.5% of the reservoir's phytoplankton, reached densities of 4,656,450 cells mL−1, with A. flos aquae (3,105,120 cells mL−1) as the dominant species, followed by M. aeruginosa (1,480,130 cells mL−1). A cyanotoxin analysis of biomass detected anatoxin-a (3.56 µg g−1), cylindrospermopsin (6.86 µg g−1), microcystin LR (0.87 µg g−1), and microcystin RR (2.47 µg g−1). This study assessed the genotoxic potential of the methanolic extract of the cyanobacterial biomass by evaluating the DNA damage and the Genetic Damage Index (GDI) in peripheral blood lymphocytes (PBLs) from healthy donors. The results showed a dose-dependent increase in the DNA damage, from 35.67 ± 4.93% at 10 µg mL−1 to 95.67 ± 1.53% at 100 µg mL−1, with a corresponding rise in the GDI from 0.61 ± 0.02 to 2.39 ± 0.07. The extract also caused the concentration-dependent hemolysis of red blood cells, with 5.63% hemolysis at the highest concentration (200 µg mL−1). These findings underscore the significant genotoxic risks posed by cyanotoxins from biomass extracts of A. flos aquae and M. aeruginosa, particularly in water sources used for human consumption. [ABSTRACT FROM AUTHOR]

Purpose: Life cycle assessment (LCA) distinguishes three types of water use: (1) consumptive water use, (2) degradative water use, and (3) in-stream water use. When it comes to assessing the impact of turbine water use (TWU, major source of in-stream water use) in LCA, so far, no method exists to quantify the related environmental impacts. Here, we developed the first midpoint characterization factors (CFs) with global coverage for turbine water use of storage and pumped storage hydropower power plants. Methods: The midpoint CF at the basin scale describes the hydropower regulation potential (HRP) [HDOR·y] per TWU [m3]. The HRP indicates the probability of how strongly the natural flow regime of a river is potentially affected by all upstream reservoir operation, calculated as the quotient between reservoir volume [m3] and the annual river discharge [m3/y]. The hydropower degree of regulation (HDOR) thereby equals the unitless m3/m3 fraction. The TWU depends on the electricity production [kWh] and the turbine efficiency [m3/kWh]. We tested the sensitivity of the input data on the calculated CFs for four parameters (discharge, turbine efficiency, multipurpose allocation, and plant type). Furthermore, we performed a case study to analyze if consumptive and TWU impacts of producing 1 kWh are correlated or not. Results and discussion: The calculated CFs for the 342 basins vary from 1.13E-13 HDOR·y/m3 to 3.28E10-7 HDOR·y/m3. The HDOR values range from 0.0015 to 16.66, and the TWU varies between 0.0030 km3 and 2824 km3. A HDOR ≥ 0.02 can be interpreted as affected basin, and only 23 out of 342 basins have a HDOR below this threshold. This confirms that TWU of hydropower production can have important environmental impacts. The sensitivity analyses revealed that discharge and turbine efficiency are the most sensitive parameters because they are influencing almost all basins. The results of the case study showed that a high consumptive water-use impact does not automatically lead to a high TWU impact and vice versa (R2 values of 0.0081 and 0.003). Conclusion: Our study highlights that it is important to account for the environmental impacts of in-stream water use in LCA, as otherwise, the environmental impact can be underestimated, which could lead to wrong conclusions. However, the CFs are not meant to replace a local risk assessment of hydropower reservoir operation and should only be used for relative comparison between basins. The CF application in LCA will represent a step forward towards more sustainable hydropower development. [ABSTRACT FROM AUTHOR]

Information pertaining to a reservoir's bathymetry is of utmost significance for water resource sustainability and management. The current study evaluated and compensated the reservoir's bathymetric patterns established using radial basis function (RBF) approaches. Water depth data were acquired by conventionally rolling out a measuring tape into the water. The water depth data were split into three (3) categories, i.e., training data, validation data, and test dataset. Spatial variations in the field-measured bathymetry were determined through descriptive statistics. The thin-plate spline (TPS), multiquadric function (MQF), inverse multiquadric (IMQF), and Gaussian function (GF) were integrated into RBF to establish bathymetric patterns based on the training data. Spatial variations in bathymetry were assessed using Levene's k-comparison of equal variance. The coefficient of determination ( R 2 ), root mean square error (RMSE) and absolute error of mean (AEM) techniques were used to evaluate the uncertainties in the interpolated bathymetric patterns. The regression of the observed estimated (ROE) was used to compensate for uncertainties in the established bathymetric patterns. The Levene's k-comparison of equal variance technique revealed variations in the predicted bathymetry, with the standard deviation of 8.94, 6.86, 4.36, and 9.65 for RBF with thin-plate spline, multi quadric function, inverse multiquadric function, and Gaussian function, respectively. The bathymetric patterns predicted with thin-plate spline, multiquadric function, inverse multiquadric function, and Gaussian function revealed varying accuracy, with AEM values of −1.59, −2.7, 2.87, and −0.99, respectively, R 2 values of 0.68, 0.62, 0.50, and 0.70, respectively, and RMSE values of 4.15, 5.41, 5.80 and 3.38, respectively. The compensated mean bathymetric values for thin-plate spline, multiquadric function, inverse multiquadric function, and Gaussian-based RBF were noted to be 18.21, 17.82, 17.35, and 18.95, respectively. The study emphasized the ongoing contribution of geospatial technology towards inland water resource monitoring. [ABSTRACT FROM AUTHOR]

Microplastic concentrations were studied in surface waters of two reservoirs playing an important role in water storage and supply in Vietnam, the Dau Tieng and Tri An reservoirs, by collecting water samples during dry and rainy seasons. Microplastic mean concentration (including all sites and seasons per reservoir) was of 3.96 ± 1.38 items m−3 at Dau Tieng and 4.04 ± 1.35 items m−3 at Tri An, and is in the range of concentrations found in other reservoirs studied worldwide. We noted that microplastic spatial distribution was driven by difference levels of anthropogenic activities and population density surrounding each area of the reservoirs. Between the two seasons, microplastic mean abundance did not change at the level of the Dau Tieng reservoir (4.36 ± 1.71 items m−3 and 3.57 ± 0.95 items m−3 during dry and rainy season, respectively), but their value significantly decreased at specific sites under intense anthropogenic activities during the rainy season. Meanwhile, in Tri An reservoir, mean microplastic abundance and size significantly decrease during the rainy season. Although the mean abundances are low value, ecological concern needs to be addressed because of the important touristic activities and their potential impact to the quality of the water and to the agriculture development of the surrounding areas. We therefore questioned microplastic as a new parameter to include into local environmental monitoring network, and we recommended to consider microplastic as an important parameter in the monitoring control of the surface water quality of the two reservoirs. [ABSTRACT FROM AUTHOR]

The process of dredging reservoirs serves the purpose of preserving water storage capacity and ensuring the functionality of navigational channels. Additionally, it has the potential to mitigate the presence of pollutants and chemicals that pose risks to both the environment and human well-being. This review article examines the many ways of disposal and treatment of dredged sediment, as well as the ecological and economic advantages associated with these approaches. Algae and reed-based treatment methods have the potential to effectively and economically remediate and sustainably manage dredged sediments. Landfills and ocean dumping are widely utilized methods for the disposal of excavated materials. However, other approaches such as land reclamation, the use of fill material, and the preservation of wetlands can offer cost-effective solutions while also contributing to environmental conservation. The implementation of sediment cleaning, stabilization, and solidification techniques has the potential to effectively mitigate waste and improve the quality of sediment, hence facilitating its reuse. Algae and reed-based treatment systems have been found to effectively mitigate disposal costs and contribute to environmental enhancement. Additionally, the practice of reusing dredged sediments has been recognized as a valuable strategy in promoting a circular economy. [ABSTRACT FROM AUTHOR]

Composite xerogel films with structural orientation, controlled swelling degree, and drug‐release ability are prepared using biocompatible megamolecular liquid crystalline polysaccharide (sacran) secreted by a cyanobacterium Aphanothece sacrum. The sacran xerogel films (Sac‐XFs) are formed by drying sacran aqueous solution including vitamin C (L‐ascorbic acid, AA) and trehalose under various conditions. In X‐ray diffraction and differential scanning calorimetry of Sac‐XFs, diffractions or melting points of either AA or trehalose are not detected, indicating no crystal formation. Additionally, the stability of entrapped AA in Sac‐XFs is evaluated through changes in film color and percentage loss, to indicate that AA stability is enhanced by entrapment in Sac‐XFs in the presence of trehalose. Scanning electron microscopy of Sac‐XFs reveals the morphological orientation, and number of striped lines along the longitudinal axis of film edges on side views while no visible textures in top views. When Sac‐XFs are immersed in water, anisotropic swelling is observed, and anisotropy decreases with an increase in the drying temperature of the films. AA is released preferentially from the hydrogel sheet edges, indicating the direction‐controlled release. Thus, the trehalose/sacran composite xerogels offer an alternative platform for preserving and controlled‐releasing sensitive substances for fields of foods, pharmaceutics, and cosmetics. [ABSTRACT FROM AUTHOR]

In this study, we explore the potential of assimilating satellite-derived reservoir storage data into the global-scale hydrodynamic model CaMa-Flood, focusing on the Yangtze River basin. We evaluated three data assimilation (DA) methods: direct assimilation (DIR), anomaly based assimilation (ANO), and normalized assimilation (NOM). Our results show that the DIR method achieved the most significant improvements in reservoir storage and downstream discharge simulations. DIR reduced the average relative root mean square error (rRMSE) of reservoir storage estimates by 80.5%, and increased discharge correlation (ΔCC) by 78.6% in the 14 validated discharge stations. ANO, while effective in certain cases, led to mixed results, with 56.4% of the 39 assimilated dams showing improved storage estimates and a modest 7.8% reduction in average RMSE. NOM had minimal impact, with negligible changes in RMSE or discharge correlation (ΔCC). The direct assimilation method (DIR) consistently outperformed the others, improving both reservoir storage and downstream discharge estimates. However, the magnitude of improvement varied across locations, highlighting the need for the further refinement of DA techniques and input data, especially for regions with complex reservoir operations. Our findings enhance reservoir representation in global hydrodynamic models and improve the predictability of river dynamics and water resource management. [ABSTRACT FROM AUTHOR]

Many research findings have proven that the system of porous medium reservoirs exhibits different heterogeneous structures at various scales, demonstrating some form of self-similarity with fractal characteristics. In this paper, fractal theory is incorporated into the reservoir to investigate coupled flow between reservoir and horizontal well. By examining the pore structure of highly heterogeneous reservoirs, the fractal dimension can be determined. Analytical methods are utilized to solve the Green function of a point source in a reservoir with fractal characteristics. Employing Green's function and the principle of spatial superposition, a finite flow model for a horizontal well coupled with a fractal reservoir is developed to calculate the flow rate and flow profile of the horizontal well. The model also accounts for the impact of wellbore friction and is solved numerically. A specific example is used for calculation to analyze the influence of fractal parameters on the production and flow rate of the horizontal well. When considering the fractal characteristics of oil reservoirs, the flow rate of the horizontal well is lower than that in Euclidean space. As the fractal dimension increases, the connectivity of pores in the reservoir improves, making it easier to drive the fluid into the wellbore, and the flow distribution along the wellbore becomes more uniform. Conversely, as the anomalous diffusion index increases, the connectivity between pores deteriorates, thus the distribution of flow rate along the wellbore becomes more uneven. [ABSTRACT FROM AUTHOR]

This study deals with unraveling the diagenesis-induced porosity evolution in a mixed clastic-carbonate sequence of the Middle Permian Indus Basin, Pakistan. Multiple data sets including outcrop, petrography, cathodoluminescence, scanning electron microscopy (SEM), mineralogy, and geochemical isotopic compositions were integrated to establish a link between porosity evolution and diagenesis. The spatial thickness and facies variations of the strata at outcrop scale are inherently controlled by the underlying bathymetry of the basin with deepening westward trend. The low values of δ18O of the target strata, relative to average values of the Permian carbonate, hints to diagenetic alteration in the strata. The data sets used in this study reveal modification of the strata in four environments, that is, i) early marine diagenesis indicated by micritization, pervasive dolomitization and isopachous fibrous cements, followed by ii) meteoric dissolution, and iii) shallow burial diagenetic processes including the precipitation of blocky cement, compaction of skeletal and non-skeletal allochems, and stylolites, and iv) a deep burial environment, characterized by pressure solution, and micro-fractures. The clastic intervals host subangular to subrounded quartz grains, floating textures, and almost complete absence of deleterious clay minerals, consequently resulting in the preservation of primary porosity. The primary porosity of carbonate intervals is preserved in the form of intercrystalline and intracrystalline porosity. The secondary porosity evolved through various diagenetic phases in the form of fractures and dissolution. The diagenetic solution mediated by organic matter in carbonates may have experienced both bacterial decomposition and thermochemical sulfate reduction, precipitating sulfides within the pores. The plug porosity/permeability analyses generally suggest high porosity in the siliciclastic unit, and carbonates with wackestone fabric while lower values were observed for the inner shelf pure carbonate facies. However, both intervals show very low permeability values probably due to isolated moldic pores and intense micritization. Therefore, clastic intervals may provide an opportunity to serve as a moderate reservoir; however, the carbonate intervals possess very low permeability values and could generally be considered as low-moderate reservoir potential. [ABSTRACT FROM AUTHOR]

Romania has a rich hydrographic network, which permitted the construction of over 80 large dams on its water courses, estimating a number between 545 and 674 hydropower plants that were either built or were in a different construction stage on the rivers of Romania in 2021. These hydropower plants were often built outside specific legislation regarding ecological impacts, especially before 1990. Longitudinal fragmentation of rivers causes severe ecological impacts on biodiversity, food chains, and nutrient cycles. Someșul Cald River is the main tributary of Someșul Mic River, the most important water source for the northwestern region of Transylvania. On its course, several dams and reservoirs were built from 1968 to 1980 for electricity production and population freshwater supply. The present study aimed to analyze the length–weight relationships (LWRs) and condition factors occurring in the longitudinally fragmented Someșul Cald River. The LWRs, relative condition factor Kn, and Fulton condition factor K were determined based on total length and wet body weight. Comparisons of LWRs, Kn, and K across river sections constrained by dams showed that some fish species exhibited similar growth patterns and physiological conditions, while others differed significantly. Freshwater fish physiology is altered by longitudinal fragmentation, both natural and artificial. Barriers such as dams influence the energy gradient, limiting feed availability and, consequently, the life history of fish species. Long-term management plans regarding conservation should take into consideration existing fish species population dynamics, along with their physiological and somatic status. [ABSTRACT FROM AUTHOR]

The paper presents a simulation-based approach for optimizing CO2 injection into depleted gas reservoirs, with the goal of enhancing underground CO2 storage. The research employs a two-dimensional dynamic reservoir model, developed using Darcy's law, to describe gas flow in a pressure-homogeneous porous medium, along with real gas equations. The model integrates the Du Fort–Frenkel and finite-difference methods to accurately simulate the behavior of CO2 during injection and storage. Real data from an operational gas storage facility were used to calibrate the model. CO2sim v1 software, specifically developed for this purpose, simulates CO2 injection cycles and quiescence phases, enabling the optimization of storage capacity and energy efficiency. The reservoir model, based on the engineering of the geological structure, is discretized into approximately 16,000 cells and solved using the finite-difference method, allowing for rapid simulation of CO2 injection and quiescence processes. The average computation time for a 150-day cycle is approximately 5 min. Simulation results indicate that increasing the number of injection wells and carefully controlling the injection rates significantly improves the distribution of CO2 within the reservoir, thereby enhancing storage efficiency. Additionally, appropriate well placement and prolonged quiescence periods lead to better CO2 dispersion, increasing the storage potential while reducing energy costs. The study concludes that further development of the software, along with comprehensive technical and economic assessments, is required to fully optimize CO2 storage on a commercial scale. [ABSTRACT FROM AUTHOR]

The study was carried out to assess heavy metal concentrations in water, gills and liver of Tilapia zilli sampled from Wasai Reservoir from January 2019 to June 2020, with the aim of predicting health risk to the consumers. Sampling stations were selected based on variation of human activities around the water body. Levels of metals were determined using Microwave Plasma Emission Spectroscopy (MP-AES). The results indicated that metal concentrations in water followed the following order: Zinc (2.55 mg/L) > Chromium (0.067 mg/L) > Lead (0.058 mg/L) > Cadmium (0.031 mg/L), with Arsenic undetected. The Bioaccumulation Factor (BAF) showed that heavy metal accumulation in fish tissues was highest for Zn, followed by Pb, Cr, Cu, Cd, and As. Significant differences (P<0.05) were observed in the heavy metal concentrations across sampling stations, months, and seasons, except for Cr and Cd, which did not show significant variations (P>0.05). Fish tissue analysis revealed significant increases (P<0.05) in the gills (Cu > Pb > Zn > Cr > As > Cd) and liver (Cu > Pb > Zn > Cd > Cr > As). Pearson's correlation coefficient indicated strong positive correlations for Zn, Cr, Cd, and Pb (P<0.01), while negative correlations were observed for Cd and Cu (P<0.01). The study concluded that heavy metal pollution significantly affected fish physiology and water quality in the reservoir, primarily due to anthropogenic activities. It recommends the implementation of proper reservoir management systems to conserve this vital ecosystem and prevent its long-term deterioration. [ABSTRACT FROM AUTHOR]

Reservoir projects often have significant impacts on ecosystems. The resulting environmental problems hinder the ecologically sustainable development of project areas. Research focusing on landscape pattern vulnerability could shed light on ecological restoration in disturbed sites. However, few studies have specifically examined reservoir areas in this context. This study investigates the spatial distribution characteristics, change rules, spatial autocorrelation, and driving forces of landscape pattern vulnerability in the Qianping Reservoir area (3859.16 hm2) from 2000 to 2020 using land use data. The findings reveal several key points: (1) Over the study period, cultivated land, grassland, and forest land are the key landscape types, covering more than 90% of the area. Cultivated land decreased by 481.57 hm2 as other land use types expanded. (2) Vulnerability remained stable in the first decade but sharply increased from 2010 to 2020, showing a trend of spatial aggregation. Reservoir construction and simultaneous ecological restoration efforts led to shifts in vulnerability zones across the landscape. (3) Spatial distribution of landscape pattern vulnerability shows a positive correlation, which strengthened by 2020 compared to earlier years. (4) Man-made factors, particularly land use changes, significantly influence landscape pattern vulnerability, with their impact growing over time. These findings not only provide a scientific basis for ecological restoration and landscape reconstruction in the Qianping Reservoir area but also offer insights applicable to similar environments. Overall, this study enhances theoretical understanding of reservoir landscape pattern vulnerability and contributes valuable perspectives on ecological restoration strategies for reservoir areas. [ABSTRACT FROM AUTHOR]

The main principles of optimal flow regulation in small rivers by reservoirs are presented. New methodological approaches are considered, taking into account the need of differential analysis of the physiographic conditions of the areas where the basins of the examined rivers are located. This is of particular importance in the case of formation of regional response to global climate warming with a combination of unfavorable economic and environmental conditions. The methodological basis of the study includes the geosystem approach and a basin principle, which allow comprehensive incorporation of the effect of the totality of natural and anthropogenic factors on the formation of variations of quantitative and qualitative characteristics of water in watercourse and the ecological conditions in them. The methods of studies include the physiographic zoning of the Ural River basin within the boundaries of the Russian Federation, statistical and graphical analysis of materials of long-term hydrometeorological observations, cartography, etc. The results of the study include methodological provision and substantiation of methodological principles for optimal flow regulation of small rivers in the Ural River basin by reservoirs within the boundaries of the Russian Federation, taking into account environmental and economic criteria. They form a part of a vast list of proposals aimed at hydrological-environmental rehabilitation of small rivers. [ABSTRACT FROM AUTHOR]

This study focuses on optimizing the storage capacity of an underground natural gas storage facility through numerical modeling and simulation techniques. The reservoir, characterized by an elongated dome structure, was discretized into approximately 16,000 cells. Simulations were conducted using key parameters such as permeability (10–70 mD) and porosity (12–26%) to assess the dynamics of gas injection and pressure distribution. The model incorporated core and petrophysical data to accurately represent the reservoir's behavior. By integrating new wells in areas with storage deficits, the model demonstrated improvements in storage efficiency and pressure uniformity. The introduction of additional wells led to a significant increase in storage volume from 380 to 512 million Sm³ and optimized the injection process by reducing the storage period by 25%. The study concludes that reservoir performance can be enhanced with targeted well placement and customized flow rates, resulting in both increased storage capacity and economic benefits. [ABSTRACT FROM AUTHOR]

The practice of oil and gas exploration has confirmed the existence of recoverable shale oil resources in the Permian Lucaogou Formation on the northern edge of the Bogda Mountains. However, previous research on the development characteristics and main controlling factors of shale oil resources in this area is relatively limited. In order to elucidate the development characteristics and principal controlling factors of the shale deposit in the Lucaogou Formation, the characteristics, physical properties, diagenesis, and influencing factors of the shale ore were investigated utilising data derived from outcrop, drilling, seismic, and geochemical analysis. The findings indicate that the shale of the Lucaogou Formation is prevalent and extensive. The deposit's lithology is predominantly composed of dark grey and grey-black mud shale, interspersed with thin layers of dark grey and grey-black sandy mud shale and dolomite mud shale. The most prevalent minerals are carbonate minerals, followed by feldspar and quartz, with a notable proportion of brittle minerals. The deposit is primarily composed of dissolution pores, bedding fractures, and structural fractures, with a porosity of 1.23–3.26% and permeability of 0.012–0.076 mD, which are characteristic of ultra-low porosity and ultra-low permeability deposits. Among the three deposit types, the sandstone type exhibits the most favourable physical properties, followed by the dolomite type and the shale type, which displays the least favourable properties. The shale of the Lucaogou Formation is currently in the middle diagenetic phase, which is characterised by compaction, cementation (carbonate cementation, mudstone cementation, pebble cementation), and dissolution. The destructive effect of compaction and cementation on the physical properties is counterbalanced by the constructive effect of dissolution. The diagenetic environment has gradually changed from an alkaline environment to a slightly alkaline, slightly acidic stage. [ABSTRACT FROM AUTHOR]