High Flow Research Articles

Analytical and descriptive study of the production behavior for pilot multi-stages hydraulic fracturing wells in southeast Iraq

The hydraulic fracturing technique is a widely used technique worldwide, making it interesting to study. This technique was applied for the first time in Iraq on a tight carbonate reservoir in the Halfaya oil field. In this field, the oil production rates, and flowing pressure were low during production periods reflecting a problem for the development plan designed to increase production using a hydraulic fracture technique. Initially, the hydraulic fracture well showed high oil-producing rates, but then, quickly experienced a high decline failing to keep a stable production rate. To address this problem, it is important to describe and analyze the behavior of pilot hydraulic fracturing wells during their production period, study the inflow performance relationship (IPR), and determine the optimum wellhead pressure above the bubble point pressure (Pb) to avoid loss of lifting energy. Furthermore, it identifies the allowable flow rate to keep stable production, investigates the effect of selecting internal tubing size, and reveals a future production procedure for hydraulic fracture wells. This study reveals that the transient inflow performance relationship observed in the production history of hydraulic fracture well in the tight carbonate reservoir and traditional inflow performance relationship concepts are not applicable. The optimum wellhead pressure for stability in production for Wells w-5 and w-55 is determined to be 750 and 580 psi with optimum rates of 800 and 450 Bbl/D, respectively. The results also showed that producing at a high flow rate may cause a depletion in the fracture potential storage without giving an opportunity for a reservoir to compensate for the produced fluid into fracturing potential storage. The internal tubing size has a passive effect on the hydraulic fracture well, as an increase in size causes an unstable flow zone. Lastly, future production procedures emphasize keeping wellhead pressures stable or increasing them if they drop. This can be accomplished by re-adjusting the choke size according to any changes observed.

Response of submarine braided channels to varying inflow hydrographs: Geomorphic experiments and stratigraphic implications

AbstractSubmarine channels on the seafloor experience a range of turbidity current‐flood hydrographs. The characteristics of the flood hydrograph influence channel dimensions, the number of channel threads (i.e. braiding intensity) and the depositional properties of sandbars within the channels. However, the morphodynamic response of submarine braided channels to different hydrograph patterns is poorly understood. In this study, six geomorphic experiments are used to test how varied flood hydrographs affect the braiding intensity and sandbar geometry within submarine channels. Three experiments represent the control group with constant density‐current inflow, and three experiments use different time‐varying hydrograph patterns. The experiments show that, as the inflow‐to‐sediment discharge ratio increases, multiple small channels coalesce into a few main channels, causing a decrease in active braiding intensity defined by the channel threads with flow. When the flow returns to the initial low flow rate, active braiding intensity increases again. These observations show that the inflow‐to‐sediment discharge ratio determines the value of active braiding intensity. Additionally, active braiding intensity is directly proportional to dimensionless sediment‐stream power and dimensionless stream power, in agreement with previously established trends for both submarine and fluvial braided channels. In contrast to active braiding intensity changes, the measured sandbar aspect ratio and compactness ratio (i.e. ratio of planform area to perimeter) of submarine braided channels is insensitive to changes in the hydrograph. However, when inflows reach peak discharge, the higher transport capacity erodes pre‐existing deposits, forming noticeable erosional surfaces, and subsequently depositing thicker sandbars during that stage. These observations imply that sandbar planform morphology is largely insensitive to hydrograph, but hydrograph variability induces a greater variability in the resultant stratigraphic packages. The experimental results predict that field‐scale stratigraphy should be dominated by strata deposited during intervals of high flow, but that these strata will also exhibit reduced lateral continuity compared to formation scenarios with constant discharge.

Differential microbiome features in lake–river systems of Taihu basin in response to water flow disturbance

IntroductionIn riverine ecosystems, dynamic interplay between hydrological conditions, such as flow rate, water level, and rainfall, significantly shape the structure and function of bacterial and microeukaryotic communities, with consequences for biogeochemical cycles and ecological stability. Lake Taihu, one of China’s largest freshwater lakes, frequently experiences cyanobacterial blooms primarily driven by nutrient over-enrichment and hydrological changes, posing severe threats to water quality, aquatic life, and surrounding human populations. This study explored how varying water flow disturbances influence microbial diversity and community assembly within the interconnected river–lake systems of the East and South of Lake Taihu (ET&ST). The Taipu River in the ET region accounts for nearly one-third of Lake Taihu’s outflow, while the ST region includes the Changdougang and Xiaomeigang rivers, which act as inflow rivers. These two rivers not only channel water into Lake Taihu but can also cause the backflow of lake water into the rivers, creating distinct river–lake systems subjected to different intensities of water flow disturbances.MethodsUtilizing high-throughput sequencing, we selected 22 sampling sites in the ET and ST interconnected river-lake systems and conducted seasonally assessments of bacterial and microeukaryotic community dynamics. We then compared differences in microbial diversity, community assembly, and co-occurrence networks between the two regions under varying hydrological regimes.Results and discussionThis study demonstrated that water flow intensity and temperature disturbances significantly influenced diversity, community structure, community assembly, ecological niches, and coexistence networks of bacterial and eukaryotic microbes. In the ET region, where water flow disturbances were stronger, microbial richness significantly increased, and phylogenetic relationships were closer, yet variations in community structure were greater than in the ST region, which experienced milder water flow disturbances. Additionally, migration and dispersal rates of microbes in the ET region, along with the impact of dispersal limitations, were significantly higher than in the ST region. High flow disturbances notably reduced microbial niche width and overlap, decreasing the complexity and stability of microbial coexistence networks. Moreover, path analysis indicated that microeukaryotic communities exhibited a stronger response to water flow disturbances than bacterial communities. Our findings underscore the critical need to consider the effects of hydrological disturbance on microbial diversity, community assembly, and coexistence networks when developing strategies to manage and protect river–lake ecosystems, particularly in efforts to control cyanobacterial blooms in Lake Taihu.

Sedimentary Reservoir Characteristics of Fuyu Oil Formation in the Middle of Fuxin Uplift, Southern Songliao Basin

Currently, the Fuyu reservoir in the middle of the Fuxin uplift, located in the southern Songliao Basin, is in a high water cut development stage. The understanding of this reservoir is limited, and the distribution of favorable reservoirs remains unclear, necessitating detailed reservoir characterization. This study employs a combination of well and seismic technologies to accurately depict the sedimentary and reservoir characteristics of the Fuyu oil reservoir. By conducting detailed correlations of oil zones, a regional high-resolution isochronous stratigraphic framework is established. The division of sedimentary microfacies enables fine characterization of single sand bodies, identifying channel boundaries, clarifying lateral connectivity, and detailing the vertical contact relationships of sand bodies across different deposition periods. The results demonstrate that root-mean-square amplitude and total energy metrics effectively correspond to sand bodies in the study area and can be used to analyze sand body distribution. Provenance is primarily from the southwest to the northeast, with shallow deltas predominantly developed. Delta plain subfacies are found in zones 4-12, while delta front subfacies are in zones 1-3. Microfacies types mainly include the main distributary channel, distributary channel sides, crevasse splay, overbank sand, and underwater distributary channels. The main distributary channel reservoirs exhibit the best physical properties, with porosity ranging from 20-25%, while sand bodies at the sides of distributary channels reach 15-20%. Predicted favorable areas are mainly located at the intersections of distributary channels and structural highs, where drilling is likely to yield high oil flow.

Exploring cost-effectiveness heterogeneity of high flow nasal cannula (HFNC) therapy in acutely ill children – Insights from step-up FIRST-ABC trial using a machine learning method

To investigate heterogeneity in the cost-effectiveness of high flow nasal cannula (HFNC) therapy compared to continuous positive airway pressure (CPAP) for acutely ill children requiring noninvasive respiratory support. Using data from the FIRST-line support for Assistance in Breathing in Children (FIRST-ABC) trial, we explore heterogeneity at the patient and subgroup levels using two causal forest approaches and a seemingly unrelated regression (SUR) approach for comparison. FIRST-ABC is a non-inferiority randomized controlled trial (ISRCTN60048867) involving 24 UK paediatric intensive care units. The 'step-up' trial focuses on acutely ill children aged 0 to 15 years, requiring non-invasive respiratory support. A total of 600 children were randomly assigned to HFNC and CPAP groups in a 1:1 allocation ratio, with 94 patients excluded due to data unavailability. The primary outcome is the incremental net monetary benefit (INB) of HFNC compared to CPAP, using a willingness-to-pay threshold of £20,000 per QALY gain. INB is derived from total costs and Quality Adjusted Life Years (QALYs) at six months. Subgroup analysis showed that some subgroups such as male children, those aged less than 12 months, and those without severe respiratory distress at randomization had more favorable INB results. Patient-level analysis revealed heterogeneity in INB estimates, particularly driven by the cost component, with greater uncertainty for those with higher INBs. The estimated overall INB of HFNC is significantly larger for specific patient subgroups, suggesting that the cost-effectiveness of HFNC can be heterogeneous which highlight the importance of considering patient characteristics in evaluating the cost-effectiveness of HFNC.

High power density redox-mediated Shewanella microbial flow fuel cells

Microbial fuel cells utilize exoelectrogenic microorganisms to directly convert organic matter into electricity, offering a compelling approach for simultaneous power generation and wastewater treatment. However, conventional microbial fuel cells typically require thick biofilms for sufficient metabolic electron production rate, which inevitably compromises mass and charge transport, posing a fundamental tradeoff that limits the achievable power density (<1 mW cm−2). Herein, we report a concept for redox-mediated microbial flow fuel cells that utilizes artificial redox mediators in a flowing medium to efficiently transfer metabolic electrons from planktonic bacteria to electrodes. This approach effectively overcomes mass and charge transport limitations, substantially reducing internal resistance. The biofilm-free microbial flow fuel cell thus breaks the inherent tradeoff in dense biofilms, resulting in a maximum current density surpassing 40 mA cm−2 and a highest power density exceeding 10 mW cm−2, approximately one order of magnitude higher than those of state-of-the-art microbial fuel cells.

Development of an Ultrasonic Nebulization System for an Inverse Low Temperature Plasma Ionization Source.

An effective nebulization and evaporation of a liquid sample, like in liquid chromatography, mass spectrometry (LC-MS) couplings, is an essential requirement for the ionization of analyte molecules in the gas phase by, for example, atmospheric pressure chemical ionization (APCI) or the novel low temperature plasma (LTP)-based ion source. These LTP-based ion sources have recently gained interest in the field of atmospheric pressure ion sources, as they can cover a wide range of polarity and molecular mass. They can be used in combination with separation techniques like liquid chromatography or used as an ambient ion source. However, commercial nebulizer systems are of course not constructed to fit to home-built LTP-based ion sources, and this was one incentive to develop a new nebulization system. Instead of an atmospheric pressure chemical ionization (APCI) nebulizer, two commercial nebulizers were disassembled and remodeled to be used as nebulizing systems in an LC-MS setup using an LTP-based ion source. Based on these results, a novel nebulizer system was subsequently developed. To further improve the degree of ionization, cones to focus the LC eluent spray on the plasma region, heating applications, and auxiliary nitrogen gas for dispersion of the solvent droplets were implemented. The LOD that could be calculated via the rule of three resulted in an average of 2.0 μg/L for the APCI-nebulizer and 41 μg/L for the USN. Both could be reduced to 1.4 and 18 μg/L, respectively, by using a TPI-configuration instead of an iLTP. The linearity was equally good for both types of nebulization devices. The final nebulizer could also be operated with a high water content and flow rates higher than those of the two previous ones, indicating an important improvement step.

Boron Delta-Doping in Si : B Stacks By RP-CVD Epitaxy

Low resistivity materials are required for advanced MOS or equivalent technologies. High boron in-situ doped Si epitaxy is known to create defects that increase the resistivity. Boron delta-doping (Si:B epitaxy alternating with boron saturation layers) is a potential solution to overcome this limitation. Using the delta-doping process at 750 °C in a Reduced Pressure Chemical Vapor Deposition reactor, a resistivity two times lower than that without delta-doping (8.9x10-4 Ω.cm and 1.86x10-3 Ω.cm respectively) was achieved. SIMS characterization measured a total boron concentration of 3.3x1021 at.cm-3. However, the delta-doping processes , as a function of the soaking volume (product of B2H6 flow and saturation time), resulted in low crystal quality and highly stressed layers. Moreover, thin layers were observed by TEM likely due to the formation of the SiBx phase at each saturation layer. For an equivalent soaking volume, a better crystal quality was obtained with a high B2H6 flow and short saturation time.

Benchmarking of HCl-Based Cyclic Deposition / Etch (CDE) and Single Deposition / Etch (DE) Processes for Selective Epitaxial Growth of SiGeC:B Films

In this paper, SiGeC:B growth behaviors at 550 °C, 10 Torr, were studied in a 300 mm industrial Reduced Pressure-Chemical Vapor Deposition reactor using a Si2H6/GeH4/SiH3CH3/B2H6 chemistry. Carbon atoms, for both SiGeC and SiGeC:B layers, were only incorporated into substitutional sites, with concentrations up to ~ 1.4 at%. It appeared that in-situ boron doping at a level of 1x1020 at.cm-3 did not modify the substitutional carbon incorporation. However, carbon and boron atoms were shown to compete for substitutional incorporation sites, as outlined by the increased SiGeC:B films resistivity. Cyclic Deposition / Etch (CDE) and Deposition / Etch (DE) processes were then benchmarked on blanket Si substrates and blanket Si wafers covered with 10 nm of Si3N4, with the aim to achieve selective growth on patterned wafers. The CDE process consisted of 10 cycles with deposition steps at 550 °C, 10 Torr and etch steps at 550 °C, 50 Torr with a very high HCl flow. The simpler DE process consisted in a single deposition step at 550 °C, 10 Torr, followed by a single etch step at 550, 575 or 600 °C, 600 Torr, with a very low HCl flow. CDE and DE processes both resulted in a rather low etch selectivity of 1.8 and produced slightly rough SiGeC:B surfaces. Finally, it was shown that the use of a HCl-based CDE process is not a viable solution to obtain high quality SiGeC:B films on patterned wafers at low growth temperatures. Meanwhile, DE yielded higher quality if slightly rough SiGeC:B layers.

Adaptive (re)operations facilitate environmental flow maintenance downstream of multi-purpose reservoirs

Multi-purpose reservoirs support socioeconomic development by providing irrigation, domestic water supply, hydropower, and other services. However, impoundment of water impacts instream aquatic ecosystems. Thus, the concept of minimum environmental flows (MEFs) was established to restore the benefits of naturally flowing rivers by specifying minimum flow rates to be maintained downstream of dams. But varying legislative contexts under which multi-purpose reservoirs operate may not always necessitate MEF releases. To what extent the release of MEF affects other sectoral benefits remains an open-ended and possibly a site-specific inquiry. A related issue is − how does the order in which releases are prioritized influences sectoral performances? We analyse these issues for the Nagarjuna Sagar reservoir, one of the largest multipurpose reservoirs in southern India. We formulate two versions of a multi-objective decision problem. PF_MEF formulation prioritizes MEF releases over releases for water demand satisfaction, followed by hydropower releases. PF_nMEF formulation follows the regional legislative rule releasing first for demand satisfaction, followed by hydropower and MEF releases. The objectives include: annual demand deficits (minimize), hydropower production (maximize), reliability of maintaining MEF (maximize), and reliability of non-exceedance of high flows downstream (maximize). A dynamic rule using radial basis functions (RBFs) specifies releases as a function of reservoir storage and the Borg multi-objective evolutionary algorithm is used to identify the Pareto approximate solutions. The reliability of MEF satisfaction, annual demand deficits, and hydropower production attained across the Pareto-optimal strategies obtained for PF_MEF (PF_nMEF) formulation is 86–99 % (63–80%), 47–1063 (17.6–340) Mm3, and 3452–3703 (3408–3650) GWh, respectively. Results thus indicate that prioritizing MEF releases improves can meet MEF requirements without significant compromises in other objectives. We hypothesize that similar investigations may reveal how simple modification of release order may improve ability of other reservoirs to meet environmental goals.

Concentric circular flow field to improve mass transport in large-scale proton exchange membrane water electrolysis cells

Uniform reactant supply is challenging for high-performance proton exchange membrane water electrolysis (PEMWE) in renewable energy storage. The anode flow-field pattern, anode flow-field orientation, and stoichiometric ratio influence mass transport. In this study, the performances of two flow-field patterns were compared for a single PEMWE cell with an active area of 100 cm2. Straight serpentine was used as the reference model and a concentric circle with an arc shape was designed. In addition, the optimal anode flow field orientation and stoichiometric ratio were determined. The results indicate that the optimal anode flow-field pattern differs depending on the stoichiometric ratio. At low flow rates, mass transfer via diffusion was dominant; therefore, a straight serpentine flow was preferred. In contrast, a concentric circle, which induces a significant differential pressure between adjacent channels, is preferable at a high flow rate. This is because convection is dominant in mass transfer. Maintaining a stoichiometric ratio of 10 or more is recommended during the operation. At a ratio of less than 10, the reactant was depleted at a high current density, and the mass transfer resistance increased. In addition, water is better distributed by gravity and buoyancy when the electrolyte membrane is parallel to the ground, and the anode flow path is above the porous medium. This leads to high PEMWE cell performance.

Pilot-scale capacitive deionization for water softening: Performance, energy consumption, and ion selectivity

Capacitive deionization (CDI) has emerged as an efficient process for hardness control than traditional water-softening technologies. However, few systematic studies have been conducted on water softening using pilot-scale CDI systems. For industrial applications, it is essential to investigate deionization performance, energy consumption, and selectivity for divalent cations through pilot-scale studies. In this study, we examined the deionization performance and energy consumption of a pilot-scale CDI process for effective water softening. The key operational variables analyzed were the applied voltage (200–300 V (i.e., 1.0–1.5 V per pair)), feed concentration (550–1250 mg/L), recovery ratio (50–80 %), flow rate (3–5 L/min), and adsorption/desorption time (80–180 s). Within this range, a high voltage, low feed concentration, low recovery ratio, high flow rate, and long adsorption/desorption times are advantageous for the total dissolved solids (TDS) removal ratio. In terms of energy efficiency, expressed as TDS removal per unit energy consumption, a low voltage, low feed concentration, low recovery ratio, fast flow rate, and long adsorption/desorption time are beneficial. Additionally, we investigated the selective removal of Ca2+ over Na+ under various operating conditions, as well as its impact on enhancing energy efficiency. The pilot CDI system achieved a Ca/Na selectivity coefficient of approximately 2.4 and it was analyzed to achieve up to 45 % energy-saving efficiency compared to nonselective systems (i.e., selectivity coefficient = 1). The results of this study are expected to provide valuable data for the application of CDI to water softening and hardness control processes.

The Effect of High Flow Nasal Cannula (HFNC) on the Use of Ventilators in Severe to Critical COVID-19 Patients

The Effect of High Flow Nasal Cannula (HFNC) on the Use of Ventilators in Severe to Critical COVID-19 Patients

Developments in the epidemiology of calcium channel blocker poisoning and implications for management

Purpose of review The aim of this study was to outline recent developments in calcium channel blocker (CCB) poisoning. The dihydropyridine CCB amlodipine is commonly prescribed in the United States, and amlodipine poisoning is increasing in frequency, presenting new challenges for clinicians because current paradigms of CCB poisoning management arose from literature on non-dihydropyridine agents. Recent findings Amlodipine is now the most common CCB involved in poisoning. High-dose insulin is a potent inotrope and vasodilator; as such, it should be used cautiously, and typically in conjunction with vasopressors, as it theoretically may worsen vasodilation in amlodipine poisoning. High-dose insulin is best used when some degree of cardiogenic shock is suspected. Venoarterial extracorporeal membrane oxygenation utilization in CCB poisoning appears to be increasing, but high flow rates may be needed to combat amlodipine-induced vasoplegia. Intravenous lipid emulsion cannot be routinely recommended but may have a role in peri-arrest situations. Adjunct treatments such as angiotensin II, methylene blue, and hydroxocobalamin offer theoretical benefit but warrant further study. Summary Amlodipine causes most cases of CCB poisoning and can induce both cardiogenic and distributive shock through multiple mechanisms. Clinicians should tailor treatment to suspected shock etiology, be aware of adjunct treatments for refractory shock, and consult an expert in poisoning.

Heat transfer and friction factor analysis for tomato puree flowing in a concentric-tube heat exchanger.

The heat and momentum transfer of tomato puree through a concentric-tube heat exchanger over a range of generalized Reynolds number (0.05<Re<66.5) was experimentally and numerically analyzed. Thermophysical and rheological properties of tomato puree (12°Brix) were measured from 20 to 60°C. The velocity, pressure, and temperature were calculated using the computational fluid dynamics (CFD) software FLUENTTM with temperature-dependent transport properties. The thermal operation of the concentric-tube exchanger was satisfactorily predicted using CFD, indicating accurate measurement of tomato puree properties with temperature variations. A concordance was found between the calculated Fanning friction factor and generalized Reynolds with the experimental correlation. A modified Sieder-Tate correlation was established, which allows properly expressing the Nusselt number as a function of the Peclet number. Simple correlations for the mechanical work and the heat transfer rate as a function of the volumetric flow rate were derived. The thermal efficiency was high at low puree flow rates but decreased with higher rates. However, at high flow rates, ceased its decline, instead showing a slight improvement. The analysis confirmed higher heat transfer rates in the concentric-tube heat exchanger compared to a plain tube at low puree flow rates. The results offer valuable insights for assessing diverse operational conditions in dairy, beverage, sauce, and concentrated food industries. Additionally, they also enhance the analysis and design of concentric-tube heat exchangers. PRACTICAL APPLICATION: The knowledge of the rheological and hydrodynamical behavior of fluids in concentric-tube heat exchangers allows to explore a set of different operating conditions to improve the yield and effectiveness on the system heating/cooling design.

Enhancing charpy absorbed energy of aged duplex lightweight steel plates through TRIP and TWIP mechanisms

Ensuring toughness in thick hot-rolled plates remains a challenge for lightweight steels in automotive, shipbuilding, military, and construction industries despite improved tensile properties. This study investigated the Charpy absorbed energy of thick hot-rolled Fe-0.4C-15Mn-6Al duplex lightweight steel plates exhibiting TRIP and TWIP mechanisms, aged at 450–500 °C to precipitate κ-carbides. Fracture initiation and propagation energies measured from instrumented Charpy impact testing were analyzed through microstructural and microfracture analyses. The 500 °C-aged (A500) specimen showed the highest Charpy absorbed energy, composed of the highest fracture initiation and propagation energies across all test temperatures, particularly due to active TWIP and TRIP mechanisms along with significant κ-carbide precipitation strengthening. Despite predominantly ductile fracture modes, regardless of aging temperature and test temperature, deformation mechanisms were influenced by stacking fault energy (SFE). Aging resulted in κ-carbide precipitation, reducing C and Mn contents in austenite and lowering SFE. At 25 °C, the superior energy absorption of the A500 specimen (296 J) was attributed to its high flow stress and extensive roughness in the fracture surface due to crack deflection in the fracture initiation region and zigzag crack propagation. The Charpy absorbed energy decreased significantly at lower temperatures due to limited development of slip line field and less zigzag crack propagation. Despite this, the A500 specimen maintained the highest energy absorption due to its optimized TWIP and TRIP mechanisms and κ-carbide precipitation strengthening.

Normal fault architecture, evolution, and deformation mechanisms in basalts, Húsavik, Iceland: Impact on fluid flow in geothermal reservoirs and seismicity

Faults within layered basaltic sequences significantly influence hydrothermal fluid flow in shallow geothermal reservoirs and potentially during CO2 sequestration and storage. Nevertheless, their characterization regarding fault zone architecture, fluid flow, deformation mechanisms, and seismic potential remains underdeveloped. This study addresses this gap by integrating structural and microstructural observations with X-ray diffraction analyses of exposed normal-transtensional faults associated with the seismically active Húsavík-Flatey Fault in the Tjörnes Fracture Zone, Northern Iceland. Our findings demonstrate that the evolution of basalt-hosted normal-transtensional faults progresses through distinct stages: (1) low-displacement fault propagation from pre-existing cooling joints; (2) fault linkage via dilational jogs; (3) damage zone/fault core growth through brecciation and cataclastic processes; (4) shear localization along sharp slip surfaces; and (5) smearing of volcaniclastic interbeds along the principal fault plane. Evidence of shear localization, truncated clasts, and hydrothermal breccias/veins suggests repeated seismic slip events facilitated by overpressured fluids. Conversely, the presence of clay-rich foliated cataclasite indicates aseismic slips during interseismic periods. Slip along fault jogs, bends, geometric irregularities, and orientation changes causes the dilatant opening of the fault planes and extensional horsetail fractures at fault tips. These structures create main tabular zones for lateral movement of hydrothermal fluids parallel to the fault strike in shallow geothermal reservoirs situated in active extensional-transtensional tectonic settings. In addition, the dilational jogs and the intersection of horsetail veins with the hosting faults may define linear zones of high structural permeability and intense localized fluid flow parallel to the σ2 paleostress orientation and finally mineral precipitation. The results of this study can be utilized to improve models of geothermal fluid flow for enhanced recovery in basaltic reservoirs and assess seismic risk in basaltic faults.

Company reputation and dividend payout

Purpose The purpose of this paper is to examine the association between company reputation and dividend policy. Design/methodology/approach In this study, sample of 98,809 firm-year observations from 22 countries covering 2005–2016 were used. Findings Firm reputation concerns are associated with higher propensities to pay dividends and payout ratios. Further, this positive effect is more pronounced for firms with high free cash flows, high information asymmetry and low institutional monitoring. The results are robust to an instrumental variable approach, propensity score matching and the Heckman two-stage correction approach while addressing endogeneity concerns. Practical implications These findings have significant implications for various stakeholders, such as existing and potential investors, managers, policymakers and regulators, by providing insights into the relationship between corporate reputation and firm dividend payout decisions. Corporate reputation is highlighted as crucial for accessing finance, emphasizing the role of national regulators and policymakers in facilitating firms' efforts to improve their reputation. The study highlights the dynamics of corporate reputation and dividend payout, calling for proactive engagement from regulators and policymakers. Crafting policies conducive to reputation-building can enhance firms' financial prospects, indicating the need for strategic interventions at managerial, regulatory and policy levels. Understanding the influence of economic context is crucial for firms to tailor reputation management strategies and optimize funding opportunities in different economic environments. Originality/value Overall, results suggest that reputation serves as a disciplining mechanism, where firms will pay dividends to maintain their reputations.

Lower mortality risk associated with remdesivir + dexamethasone versus dexamethasone alone for the treatment of patients hospitalized for COVID-19

Abstract Background Treatment guidelines were developed early in the pandemic when much about COVID-19 was unknown. Given the evolution of SARS-CoV-2, real-world data can provide clinicians with updated information. The objective of this analysis was to assess mortality risk in patients hospitalized for COVID-19 during the Omicron period receiving remdesivir+dexamethasone versus dexamethasone alone. Methods A large, multicenter US hospital database was used to identify hospitalized adult patients, with a primary discharge diagnosis of COVID-19 also flagged as “present on admission” treated with remdesivir+dexamethasone or dexamethasone alone from December 2021 to April 2023. Patients were matched 1:1 using propensity score matching and stratified by baseline oxygen requirements. Cox proportional hazards model was used to assess time to 14- and 28-day in-hospital all-cause mortality. Results A total of 33 037 patients were matched, with most patients ≥65 years old (72%), White (78%), and non-Hispanic (84%). Remdesivir+dexamethasone was associated with lower mortality risk versus dexamethasone alone across all baseline oxygen requirements at 14 days (no supplemental oxygen charges: adjusted hazard ratio [95% CI]: 0.79 [0.72-0.87], low flow oxygen: 0.70 [0.64-0.77], high flow oxygen/non-invasive ventilation: 0.69 [0.62-0.76], invasive mechanical ventilation/extracorporeal membrane oxygen (IMV/ECMO): 0.78 [0.64-0.94]), with similar results at 28 days. Conclusions Remdesivir+dexamethasone was associated with a significant reduction in 14- and 28-day mortality compared to dexamethasone alone in patients hospitalized for COVID-19 across all levels of baseline respiratory support, including IMV/ECMO. However, the use of remdesivir+dexamethasone still has low clinical practice uptake. In addition, these data suggest a need to update the existing guidelines.

Population genetics of Babesia vogeli based on the mitochondrial cytochrome b gene

The current study aimed at population genetic characterization of B. vogeli based on the cytochrome b (cyt b) gene sequences (≥ 685 bp) available in the GenBank. Phylogenetic trees placed all the sequences of B. vogeli in a single large monophyletic clade; however, it was further divided into two subclades (Bv1 and Bv2). Out of seven nucleotide variations observed between Bv1 and Bv2 subclades, four were synonymous (G92A, C170T, T488C and A659G), and three were non-synonymous (G324A, C438A and G465A) resulting in amino acid substitutions at three places (V108I, L146I and V155I). Within different B. vogeli populations, the nucleotide and haplotype diversities were low. The median-joining haplotype network revealed only two haplotypes (Hap_1 and Hap_2). A geographical sub-structuring was noticed in the B. vogeli populations, with moderate genetic differentiation (FST = 0.05000; P < 0.05) and a very high gene flow (Nm = 4.75) between Indian and Chinese populations. Neutrality tests and mismatch distributions for the Indian population and the overall dataset of B. vogeli indicated a constant population size. This study provides the first insight into the genetic characterization, population genetics and haplotype network of B. vogeli based on the cyt b gene.