Changes In Flow Research Articles

Urban exodus or suburbanisation? Medium-term COVID-19 pandemic impacts on internal migration in Japan

The COVID-19 pandemic has profoundly affected internal migration patterns worldwide. Most previous studies have reported on pandemic-induced changes in internal migration using data from 2020 and 2021. Therefore, little is known about the pandemic’s medium-term impact. To address this gap, this study investigated an annual series of migration patterns from 2019 to 2023 in Japan. At the municipal level, relationships between net migration rates and population density indicated that the urbanisation trend became weak in 2020, compared to that in 2019, and it was the weakest in 2021. The urbanisation degree became stronger in 2023, increasing to the level in 2020. Using annual inter-municipal migration flows, this study then investigated changes in migration flows to/from and within three major metropolitan areas (Tokyo, Nagoya, and Osaka). The changes in sizes of these flows and migration effectiveness index suggested that the pandemic had the largest impact in the Tokyo metropolitan area, among the three areas, and it stimulated intra-metropolitan migration as suburbanisation, rather than net out-migration as ‘urban exodus’, in Japan. The overall results indicated that the pandemic had the largest impact in 2021, which got smaller as the migration patterns recovered to the pre-pandemic ones in 2023.

Numerical investigation of slip effects on heat and mass transfer in a vertical channel with immiscible micropolar and viscous fluids of variable viscosity

AbstractThis study investigates the fluid flow, heat, and mass transfer phenomena within a vertical channel containing two immiscible fluids, with a particular focus on slip effects. These effects include no slip, velocity slip, thermal slip, and multiple slips, each analyzed with appropriate boundary conditions. The study thoroughly examines key characteristics, such as variations in thermal conductivity and viscosity. Using a sixth‐order Runge–Kutta numerical method implemented using Mathematica, the study achieves precise solutions for complex scenarios. The detailed results show how the various slip mechanisms and relevant parameters interact with each other in complex ways. These findings are useful for both theoretical understanding and application in real‐life engineering situations. This study also gives important information about how fluid flow, heat transfer, and mass transfer change under different slip effects. It looks at these effects and shows how they change visually. It also carefully calculates and analyzes engineering parameters like the Nusselt number, shear stress, and Sherwood number using bar charts, showing how they affect and behave. The study resulted in velocity slip having a minimal impact on temperature, whereas thermal slip resulted in higher temperatures. Both velocity and thermal slip conditions simultaneously result in the lowest temperatures.

A 2D numerical model for simulating landslide dam failure and induced morphological changes considering multi-layer and non-uniform sediments

ABSTRACT Landslide dams are formed by the blockage of rivers with landslides, or any debris flows. Such dams are prone to failure and therefore, simulation of their failure and induced morphological changes is of great importance for hazard mitigation. Multi-layer and non-uniform sediments are usually observed in landslide dam materials, but these are rarely considered in simulations. In this paper, a two-dimensional numerical model considering multi-layered and non-uniform sediments is proposed. The model solves the shallow water equations, the Exner equation considering the different size fractions and Hirano's active layer equation based on a finite volume scheme in a weakly coupled approach. Two experimental tests are used to assess the applicability and accuracy of the model. The results show that it can well simulate the flow and morphological changes, as well as the surface coarsening and fining phenomena related to multi-layer and non-uniform sediments. The numerical results of dam failure process and morphological changes are in overall good agreement with the experiments, but the peak discharge and bed elevation tend to be underestimated when finer material is considered. Finally, the influence of sediments fractions and active layer depth on numerical results, as well as the limitations of the model are discussed.

Effects of sodium-glucose transporter-2 inhibition on systemic hemodynamics, renal function, and intra-renal oxygenation in sepsis-associated acute kidney injury.

People with type 2 diabetes mellitus treated with sodium-glucose transporter-2 inhibitors (SGLT2i) have lower rates of acute kidney injury (AKI). Sepsis is responsible for the majority of AKI in critically ill patients. This study investigated whether SGLT2i is renoprotective in an ovine model of Gram-negative septic AKI. Sixteen healthy merino ewes were surgically instrumented to enable measurement of mean arterial pressure, cardiac output, renal blood flow, renal cortical and medullary perfusion, and oxygenation. After a 5-day recovery period, sepsis was induced via slow and continuous intravenous infusion of live Escherichia coli. Twenty-three hours later, sheep were randomized to receive an intravenous bolus of 0.2 mg/kg empagliflozin (n = 8) or a fluid-matched vehicle (n = 8). Empagliflozin treatment did not significantly reduce renal medullary hypoperfusion or hypoxia, improve kidney function, or induce histological changes. Renal cortical oxygenation during the intervention period was 47.6 ± 5.9mmHg in the empagliflozin group compared with 40.6 ± 8.2mmHg in the placebo group (P = 0.16). Renal medullary oxygenation was 28.0 ± 18.5mmHg in the empagliflozin compared with 25.7 ± 16.3mmHg (P = 0.82). Empagliflozin treatment did not result in significant between-group differences in renal blood flow, kidney function, or renal histopathological changes. In a large mammalian model of septic AKI, a single dose of empagliflozin did not improve renal microcirculatory perfusion, oxygenation, kidney function, or histopathology.

Network power and exclusion of informal waste pickers when plastic flows change: A case study of community waste banks in Klaten Municipality in Indonesia

Countries, like Indonesia, without advanced waste management systems and with higher levels of population and consumption growth, face particular challenges in addressing plastic waste and marine pollution. To address and prevent plastic marine pollution, Indonesia introduced mitigation initiatives, such as Extended Producer Responsibility, waste banks, and take back schemes. While recent research shows such approaches are able to prevent marine litter, research into their social and equity effects is scarce. This is problematic, because mitigation initiatives can have in- and exclusion effects in terms of access to valuable waste for vulnerable, informal waste actors. This article combines the sociology of network and flows with a network power typology to study how the implementation of waste banks in Klaten Municipality, Indonesia not only led to reduction in plastic pollution, but also the exclusion of cartmen, waste pickers and mobile intermediates from waste networks and thus from accessing these valuable waste flows. A waste bank is a community based business that provides households with additional income and turns household waste into economically valuable materials by trading them with recyclers. In doing so they outcompete a vulnerable group like waste pickers. Instead of waste pickers, households become part of the plastic waste networks. In addition to assessing environmental effects of (marine) plastic pollution mitigation initiatives, more scholarly attention should go towards assessing the in- and exclusion dynamics around different plastic mitigation initiatives. The sociology of network and flows is a useful lens through which to examine these in- an exclusion effects.

Engaging Mood Brain Circuits with Psilocybin (EMBRACE): a study protocol for a randomized, placebo-controlled and delayed-start, neuroimaging trial in depression

BackgroundMajor depressive disorder (MDD) is a leading cause of disability worldwide across domains of health and cognition, affecting overall quality of life. Approximately one third of individuals with depression do not fully respond to treatments (e.g., conventional antidepressants, psychotherapy) and alternative strategies are needed. Recent early phase trials suggest psilocybin may be a safe and efficacious intervention with rapid-acting antidepressant properties. Psilocybin is thought to exert therapeutic benefits by altering brain network connectivity and inducing neuroplastic changes that endure for weeks post-treatment. Although early clinical results are encouraging, psilocybin’s acute neurobiological effects on neuroplasticity have not been fully investigated. We aim to examine for the first time how psilocybin acutely (intraday) and subacutely (weeks) alters functional brain networks implicated in depression.MethodsFifty participants diagnosed with MDD or persistent depressive disorder (PDD) will be recruited from a tertiary mood disorders clinic and undergo 1:1 randomization into either an experimental or control arm. Participants will be given either 25 mg psilocybin or 25 mg microcrystalline cellulose (MCC) placebo for the first treatment. Three weeks later, those in the control arm will transition to receiving 25 mg psilocybin. We will investigate whether treatments are associated with changes in arterial spin labelling and blood oxygenation level-dependent contrast neuroimaging assessments at acute and subacute timepoints. Primary outcomes include testing whether psilocybin demonstrates acute changes in (1) cerebral blood flow and (2) functional brain activity in networks associated with mood regulation and depression when compared to placebo, along with changes in MADRS score over time compared to placebo. Secondary outcomes include changes across complementary clinical psychiatric, cognitive, and functional scales from baseline to final follow-up. Serum peripheral neurotrophic and inflammatory biomarkers will be collected at baseline and follow-up to examine relationships with clinical response, and neuroimaging measures.DiscussionThis study will investigate the acute and additive subacute neuroplastic effects of psilocybin on brain networks affected by depression using advanced serial neuroimaging methods. Results will improve our understanding of psilocybin’s antidepressant mechanisms versus placebo response and whether biological measures of brain function can provide early predictors of treatment response.Trial registrationClinicalTrials.gov Identifier: NCT06072898. Registered on 6 October 2023.

Study on dynamic mechanism of granular flow erosion and entrainment based on DEM theory

BackgroundGranular flows are common on the Qinghai–Tibet Plateau and the Hengduan Mountains in China, and their dynamic process processes have obvious erosional and entrainment effects. On the one hand, the volume of the granular flow increases by a factor of several or ten, which significantly increases its ability to cause a catastrophe; on the other hand, the eroded loose material affects the granular flow dynamics process and changes its state of motion.MethodsIn this paper, the dynamic mechanism of granular flow erosion and entrainment is investigated by DEM simulation.Purpose The effects of different substrate materials and substrate boundary conditions on granular flow erosion and entrainment are analyzed, and the effects of material mixing caused by erosion and entrainment on the state of motion of granular flow are discussed. It was verified that the kinetic mechanisms of granular flow erosion and entrainment includes impact erosion, ploughing, and shear abrasion.ResultsAnd discovered that small matrix particle size, small matrix boundary friction, and small matrix thickness lead to stronger ploughing and shear abrasion; Large matrix fractal dimensions result in stronger ploughing and weaker shear abrasion, and the granular flow does not entrain large amounts of material to the accumulation zone. Meanwhile, the dynamics of erosion and entrainment of granular flow were investigated, and the results showed that: 1. The greater the erosion rate, the greater the velocity and kinetic energy of the granular flow, the greater the distance traveled, and the smaller the apparent friction angle (i.e., the greater the mobility). 2. The amount of small granules in a granular flow changes its fluidity, the more small granules there are, the more fluid it is. 3. The fit reveals that the substrate fractal dimension has the strongest effect on the velocity and kinetic energy of granular flow, followed by substrate thickness and substrate boundary friction.

Short-term effects of antenatal betamethasone on fetal cardiovascular and circulation status: A quasi-experimental observational (before-after) study

Background: The administration of antenatal corticosteroid is a standard treatment to reduce the rate of perinatal mortality and morbidity; however, there is limited evidence regarding the potential effects of betamethasone on the constriction of the ductus arteriosus (DA). Objective: This study aimed to investigate the short-term effects of antenatal betamethasone on fetal cardiovascular and circulation status. Materials and Methods: This quasi-experimental observational (before-after) study was conducted on 32 singleton fetuses. The participants were healthy pregnant women with a diagnosis of placenta accreta spectrum who were eligible for 2 doses of betamethasone and referred to prenatal care clinic, Vali-E-Asr hospital; Tehran, Iran from January 2021-May 2022. The results of fetal echocardiography and Doppler sonography were compared before and after the administration of antenatal corticosteroid therapy. Results: Following betamethasone injection, significant increases were observed in peak systolic and diastolic velocity of the DA without constriction of the DA (p < 0.001, p = 0.002 respectively). However, no significant changes were observed in right ventricular function, tricuspid valve function, Doppler of ductus venous, and peak systolic velocity of the aortic isthmus (p > 0.05). Doppler examination of the uterine, umbilical, and middle cerebral arteries also showed no significant changes (p > 0.05). Conclusion: Considering the benefits of antenatal corticosteroid therapy, its administration seems reasonable in preterm births. The transient changes in ductal blood flow are not prohibitive. Key words: Betamethasone, Premature birth, Ultrasonography, Doppler, Echocardiography, Fetus.

Assessing small hydropower viability in water-scarce regions: environmental flow and climate change impacts using a SWAT+ based tool

Water-scarce regions, like the Mediterranean, face worsening conditions due to climate change, intensifying pressure on key economic sectors such as hydropower. Additionally, environmental conservation policies, particularly the implementation of environmental flows, present challenges for hydropower systems. Certainty regarding the impact of these factors on future hydropower production is crucial for informed decision-making in the transition to sustainable energy. This study introduces S + HydPower, a tool coupled with SWAT+ to assess climate change and watershed management effects on small hydropower plant (SHP) systems. In this study, we used this tool to investigate the consequences of implementing environmental flows and climate change on run-of-river SHPs in the Catalan River Basin District (CRBD), in Catalonia. The results show that applying environmental flows would lead to a significant 27% reduction in SHP production. However, this reduction would represent only 0.25% of the region’s current energy demand. Furthermore, the study reveals a potential 38% to 73% reduction in SHP production by the end of the twenty-first century due to the combined effects of environmental flows and climate change. This suggests a substantial decline in run-of-river SHP’s contribution to the CRBD’s electricity supply. These findings emphasize the need to explore alternative and sustainable energy sources to ensure the long-term reliability and resilience of the region’s energy supply.

Transient Decrease in Cerebrospinal Fluid Motion is Related to Cough-Associated Headache in Chiari I Malformation (Original Research Article)

Short-lasting cough-associated Headache (CAH) in patients with Chiari I Malformation (CMI) is believed to be due to transient worsening of CSF flow obstruction at the foramen magnum. We assessed changes in CSF flow in response to coughing in CMI patients with CAH and compared to those without CAH and healthy participants (HP) using real-time MRI. Seventeen CMI patients (12 with CAH, 5 without CAH) and 6 HP were prospectively assessed using real-time pencil-beam imaging (PBI) MR sequence. A 64-mm length PBI cylinder was placed at the cranio-cervical junction. CSF stroke volume (SVCSF) was assessed during resting, post-coughing and relaxation phases via a 90-second scan. SVCSF was measured at six levels at 5-mm intervals between 10 and 35 mm below the foramen magnum. During each phase, SVCSF was compared between CMI with and without CAH and HP and corrected for multiple comparisons. At multiple consecutive levels, post-coughing SVCSF was significantly lower in CMI with CAH compared to both CMI without CAH and HP (p <0.05). No differences in post-coughing SVCSF were seen between CMI without CAH and HP. At rest or relaxation phase, no differences in SVCSF were seen between patients with and without CAH but minimal differences were seen between CMI with CAH and HP. A decrease in CSF flow after coughing in CMI patients with CAH supports the notion that CAH is caused by transient worsening of CSF flow obstruction at the foramen magnum.

Fault root cause analysis using degree of change and mean variable threshold limit in non-linear dynamic distillation column

The chemical industrial processes are both dynamic and complex. The presence of instability and danger in the production process poses significant challenges to safety management. Early and accurate fault diagnosis is essential to ensure a sustainable and stable chemical process performance. Most studies in literature do not provide detailed information about diagnosing the root cause of faults in distillation columns using contribution plots. Using principal component analysis (PCA) in conventional contribution plots leads to a large number of contributing variables, making it difficult to identify the root cause of a specific fault. In this study, the authors suggest employing the Degree of Change of Contribution Values (DCC) and Mean Variable Threshold Limit (LMVT) techniques alongside the Wavelet Transform-Principal Component Analysis (WT-PCA) method to decrease the quantity of fault identification variables in a non-linear system (distillation column). The Aspen Plus software is utilized to perform a dynamic simulation of a distillation column, generating data for both normal and faulty operations. Two distinct types of faults are considered, which include loss of feed flow and feed temperature changes. This study aims to analyze the results obtained from the Hotelling T2 and SPE contribution plots by calculating the average difference between the normal and faulty conditions using the Degree of Change in Contribution Values. This procedure is performed to determine the extent of deviation from the standard state. Subsequently, the variables that have surpassed the threshold limit for means variables (LMVT) are designated as the variables that serve as the primary underlying cause of the fault. The technique was employed in a case study involving a nonlinear distillation column, and the results indicate that only one "dominant" variable intersects the LMVT by Hotelling T2, which represents the true underlying cause of the corresponding fault.

Non-stationary low flow frequency analysis under climate change

AbstractAnalysis of low river flows provides important information for effective management of water resources in a region. Despite the critical importance of understanding low flow dynamics, there is a gap in the literature regarding the use of non-stationary models to analyze low flow data under climate change in Turkey. In this research, low flow series from 80 measuring stations in Turkey are investigated by employing both stationary and non-stationary models based on the Generalized Additive Models for Location, Scale and Shape (GAMLSS). For constructing non-stationary models, 31 explanatory variables consisting of time, precipitation, temperature and atmospheric oscillation indices were used to model the parameters of the chosen distributions. The results show that stationary models are more successful at 7 stations, while non-stationary models are more successful at 73 stations. Comparisons between non-stationary models showed that for most stations, the best performing models were non-stationary models with annual precipitation as covariates. In addition, successful results were obtained when Western Mediterranean Oscillation and North Atlantic Oscillation indices were used as explanatory variables. Additionally, this study investigated 20 and 50-year return levels by fitting the non-stationary frequency distribution models for low flows over historical and projection periods under SSP2-4.5 and SSP5-8.5 climate scenarios. GAMLSS incorporated annual total precipitation, which is the most effective explanatory variable for low flows, as a covariate, and thus changes in low flows were analyzed. The results show that decreases are expected in low flows, except for the stations in the upper Euphrates basin compared to the historical period.

Cord Obstruction and Delayed Cord Clamping Do Not Affect Gut Function in Neonatal Piglets

Introduction: Birth-related obstruction of umbilical blood flow may induce hypoxic insults that affect postnatal organ adaptation. Using newborn cesarean-delivered pigs, we hypothesized that cord obstruction during delivery negatively affects physiological transition and gut maturation. Further, we investigated if delayed cord clamping (DCC) improves gut outcomes, including sensitivity to formula-induced necrotizing enterocolitis (NEC)-like lesions. Methods: In experiment 1, preterm (n = 24) and near-term (n = 29) piglets were subjected to umbilical cord obstruction (UCO, 5–7 min in utero), with corresponding pigs delivered without obstruction (CON, n = 17–22). Experiment 2 assessed preterm pigs subjected to delayed cord clamping (n = 30, 60 s) or immediate cord transection with umbilical cord milking (UCM, n = 34). Postnatal vital parameters were recorded, together with a series of gut parameters after 3 days of formula feeding. Results: UCO induced respiratory-metabolic acidosis in near-term pigs at birth (pH 7.16 vs. 7.32, pCO2 12.5 vs. 9.2 kPa, lactate 5.2 vs. 2.5 mmol/L, p < 0.05). In preterm pigs, UCO increased failure of resuscitation and mortality shortly after birth (88 vs. 47%, p < 0.05). UCO did not affect gut permeability, transit time, macromolecule absorption, six digestive enzymes, or sensitivity to NEC-like lesions. In experiment 2, DCC improved neonatal hemodynamics (pH 7.28 vs. 7.20, pCO2 8.9 vs. 9.9 at 2 h, p < 0.05), with no effects on gut parameters. Conclusion: UCO and DCC affect neonatal transition and hemodynamics, but not neonatal gut adaptation or sensitivity to NEC-like lesions. Our findings suggest that the immature newborn gut is highly resilient to transient birth-related changes in cord blood flow.

Sex differences in skin microcirculatory vascular reactivity in experimental lipopolysaccharide-induced endotoxinemia

Bacterial lipopolysaccharide (LPS) plays a leading role in the development of a systemic inflammatory response and endogenous intoxication. However, the sex differences in the functional state of the microcirculatory bed in LPS-induced endotoxinemia have been poorly studied. Objective. To study the characteristics of skin microcirculatory vascular reactivity in experimental LPS-induced endotoxinemia in male and female rats. Material and methods. Modeling of endotoxinemia was performed by intraperitoneal injection of LPS of the cell wall of the bacterium Salmonella enterica to male and female Wistar stock rats. Two doses of LPS were used: 50 mg/kg and 10 mg/kg. We used laser Doppler flowmetry to evaluate skin perfusion before and after LPS injection, blood flow changes under test conditions with local contact hypothermia caused by a thermoelement. Results. 48 hours after LPS injection, a decrease in blood flow was observed, especially pronounced at a dose of LPS 50 mg/kg. During the test with local cooling of the skin, a change in the kinetics of the reaction was noted. Blood flow reduction was 75% (LPS 50 mg/kg) and 51% (LPS 10 mg/kg), statistically significantly different from the control groups. At the same time, the classic phenomenon of “cold vasodilation” observed in control rats was absent in all groups with the injection of LPS. Maximum perfusion after restoration of blood flow in females was achieved 3 times faster than in males (LPS 10 mg/kg). Conclusion. In experimental LPS-induced endotoxinemia, a dose-dependent decrease in skin perfusion was revealed. We obtained new data on the absence of pronounced “cold vasodilation” at local contact hypothermia. The results of the study indicate a violation of the mechanisms of neurogenic vasoconstriction and endothelium-dependent vasodilation, reflecting systemic disorders of microcirculation regulation. At the same time, the females showed a more positive dynamics of blood flow restoration in the test with local cooling of the skin, indicating a greater functional reserve and a more effective mechanism of autoregulation of the blood microcirculation system. A functional test with local contact cooling of the skin is highly informative for assessing vascular reactivity and preservation of the autoregulation mechanism of microcirculation in modeling endogenous intoxication

On surface texture evolution in abrasive flow machining

ABSTRACT Abrasive Flow Machining (AFM) is highly effective for precise surface control and finishing. The process’s material removal mechanism significantly impacts surface quality, especially in complex parts. However, little research addresses how initial micro-surface textures affect AFM outcomes. This study prepared four types of initial surface profiles and machined them using various abrasive media particle sizes. The rheology of the abrasive media was analyzed, with a custom guide restricting the fluid domain to create gradient flow changes. Both experimental and simulated one-way and two-way AFM processes were conducted. Results demonstrated that the material removal efficiency improved according to an enhanced version of Preston’s equation for flat surfaces. Initial surface textures exerted more influence on material removal than anticipated. All abrasive media sizes yielded uniform surface quality, with surface roughness improvements exceeding 80%. Larger initial surface textures experienced greater material removal. Chemical element analysis confirmed the AFM process is contamination-free.

Ecosystem engineers shape ecological network structure and stability: A framework and literature review

Abstract Ecosystem engineering is a ubiquitous process where species influence the physical environment and thereby structure ecological communities. However, there has been little effort to synthesize or predict how ecosystem engineering may impact the structure and stability of interaction networks. To assess current scientific understanding of ecosystem engineering impacts via habitat forming, habitat modification and bioturbation on interaction networks/food webs, we reviewed the literature covering marine, freshwater and terrestrial food webs, plant‐pollinator networks and theory. We provide a conceptual framework and identify three major pathways of engineering impact on networks through changes in resource availability and energy flow, habitat heterogeneity and environmental filtering. These three processes often work in concert and most studies report that engineering increases species richness. This is particularly marked for engineers that increase habitat heterogeneity and thereby the number of available niches. The response of network structure to ecosystem engineering varies, however some patterns emerge from this review. Engineered habitat heterogeneity leads to a higher number of links between species in the networks and increases link density. Connectance can be negatively or positively affected by ecosystem engineer impact, depending on the engineering pathway and the engineer impact of species richness. We discuss how ecosystem engineers can stabilize or destabilize communities through the changes in niche space, diversity, network structure and the dependency on the engineering impact. Theory and empirical evidence need to inform each other to better integrate ecosystem engineering and ecological networks. A mechanistic understanding how ecosystem engineering traits shape interactions networks and their stability will be important to predict species extinctions and can provide crucial information for conservation and ecosystem restoration. Read the free Plain Language Summary for this article on the Journal blog.

Effects of changes in precipitation patterns and stream flow on stream DOC and [formula omitted] concentrations in a headwater catchment in a subtropical region of southern China

Study regionThe Guantian headwater watershed is located in the subtropical region of South China. Study focusThis study examined how changes in precipitation and consequent shifts in streamflow affect dissolved organic carbon (DOC) and nitrate (NO3−) concentrations in a headwater stream. New hydrological insights for the regionThe results indicate that stream DOC and NO3− concentrations decrease from spring to winter (0.16 mg/L/month for DOC and 0.18 mg/L/month for NO3−) and have a generally positive relationship with streamflow (p < 0.05). Changes in precipitation-concentration, precipitation-amount and consequent shifts in streamflow remarkably affect stream DOC and NO3− concentrations. When precipitation events are more heavily concentrated (when precipitation concentration index (PCI) changed from 12.81 to 18.33) from May to July, the stream DOC and NO3− concentrations tend to increase from May to July but decrease before and after this period. In addition, an increase in precipitation-amount tends to increase stream DOC and NO3− concentrations before the occurrence of peak flow and in the dry period from September to December, but decreases them in the wet period from June to September. When the precipitation-amount decreases, the trend of the change in concentration is exactly the opposite. These findings suggest that stream DOC and NO3− concentrations in the headwater stream are highly chemodynamic: they are transport-limited before the occurrence of high flow and in the dry period from September to December, while they are supply-limited in the June-September period.

From Warm to Cold: Feeding Cold Milk in Preterm Infants with Uncoordinated Oral Feeding Patterns.

Premature infants frequently face feeding challenges due to disrupted coordination of sucking, swallowing, and breathing, increasing their risk of dysphagia. There are few effective treatment options available for these infants. In adults experiencing dysphagia, consuming cold foods or liquids can be an effective strategy. This method stimulates the sensory receptors in the pharyngeal mucosa, promoting safer and more effective swallowing. We have previously demonstrated that short-duration feeding (5 swallows) with cold liquid significantly reduces dysphagia in preterm infants; however, the impact of extended cold milk feeding remains unexplored. This study aims to assess the safety of cold milk feedings in preterm infants diagnosed with uncoordinated feeding patterns and its effect on feeding performance. Preterm infants with uncoordinated feeding patterns (n=26) were randomized to be fed milk at either room or cold temperatures using an experimental, randomized crossover design. We monitored axillary and gastric content temperatures, mesenteric blood flow, and feeding performance. The findings suggest that preterm infants can safely tolerate cold milk without any clinically significant changes in temperature or mesenteric blood flow, and it may enhance certain aspects of feeding performance. These results suggest that cold milk feeding could be a safe therapeutic option for preterm infants. These results highlight the potential for further comprehensive studies to explore the use of cold milk as an effective therapeutic approach for addressing feeding and swallowing difficulties in preterm infants. Registered at clinicaltrials.org #NCT04421482.

Parvalbumin interneuron activity induces slow cerebrovascular fluctuations in awake mice.

Neuronal regulation of cerebrovasculature underlies brain imaging techniques reliant on cerebral blood flow (CBF) changes. However, interpreting these signals requires understanding their neural correlates. Parvalbumin (PV) interneurons are crucial in network activity, but their impact on CBF is not fully understood. Optogenetic studies show that stimulating cortical PV interneurons induces diverse CBF responses, including rapid increases, decreases, and slower delayed increases. To clarify this relationship, we measured hemodynamic and neural responses to optogenetic stimulation of PV interneurons expressing Channelrhodopsin-2 during evoked and ongoing resting-state activity in the somatosensory cortex of awake mice. Two-photon microscopy (2P) Ca2+ imaging showed robust activation of PV-positive (PV+) cells and inhibition of PV-negative (PV-) cells. Prolonged PV+ cell stimulation led to a delayed, slow CBF increase, resembling a secondary peak in the CBF response to whisker stimulation. 2P vessel diameter measurements revealed that PV+ cell stimulation induced rapid arterial vasodilation in superficial layers and delayed vasodilation in deeper layers. Ongoing activity recordings indicated that both PV+ and PV- cell populations modulate arterial fluctuations at rest, with PV+ cells having a greater impact. These findings show that PV interneurons generate a complex depth-dependent vascular response, dominated by slow vascular changes in deeper layers.

Sediment colour as a marker of syn-depositional and early diagenetic processes in glaciofluvial sediments

The continental red beds, encompassing a broad spectrum of genetic types, can serve as important palaeoclimatological and palaeoenvironmental archives. The origin of sediment colouration is a complex process involving abiotic processes (e.g., breakdown of original and precipitation of newly-formed minerals), which, together with biogenic factors, lead to mobilisation of redox-sensitive elements and precipitation of Fe- and Mn-(oxy)hydroxides. There is still discussion about the interpretation of the continental red beds as palaeoclimatological archives or the colour patterns reflecting ancient redox gradients. The layers coloured in red, yellow or black can be found in the Quaternary glaciofluvial sediments in the Czech Republic. We are using a combination of field study with multi-spectral petrophysical, petrological and geochemical analyses to investigate the mechanism and timing of the origin of coloured coatings in glaciofluvial sediments, and causes of cycling of Fe, Mn, and other redox sensitive elements and isotopes. The results show that both syn-depositional and early diagenetic processes are responsible for the origin of colour patterns in the Quaternary glaciofluvial sediments. The stable molybdenum and iron isotope fractionation is primarily driven by the breakdown of the primary Fe and Mn-bearing silicates and the precipitation of the secondary Fe- and Mn-(oxy)hydroxides, such as goethite and birnessite. These precipitates are the main components of colouring coatings on the detrital grains and are able to bind other redox-sensitive elements, such as Cu, As, Mo, U, and REEs. The textural patterns and geochemistry suggest that the colour features were developed in the time range of decades to several thousand years after the deposition along ancient subsurface redox gradients due to changes in groundwater flow associated with primary lithology, glaciotectonics, and seasonal changes in the active layer of permafrost. The coatings show morphological features (rods, botryoids) and geochemical signatures (e.g., increased P contents) suggesting involvement of microorganisms to their precipitation.