Effect Of Fluctuations Research Articles

Factors Associated with Retinal Microvasculature Dropout Induced by Elevation of Intraocular Pressure in Primary Open-Angle Glaucoma.

To investigate the risk factors related to decrease in vessel density (VD) observed in primary open-angle glaucoma (POAG), due to acute increase in intraocular pressure (IOP) by an ophthalmodynamometer (OPD). This cross-sectional study involved 42 eyes of participants (22 Controls and 20 POAG patients) that underwent optical coherence tomography angiography (OCT-A) to assess VD in the peripapillary region in three examination sets: primary gaze position (1), 25-degree adduction (2) and 25-degree adduction with OPD compression (3). Individual relationships between IOP levels and changes in the superficial complex VD were evaluated after image processing and exclusion of large retinal vessels. Multivariable regression analysis was used to verify factors associated with differences in VD induced by IOP elevation. A significant increase in IOP was induced by OPD compression during adduction (mean ± SD, Control: + 13.8 ± 2.8; POAG: + 13.4 ± 2.1mmHg). Only during IOP elevation (set 3), a significant VD decrease was observed both in POAG eyes (p = 0.008) and controls (p = 0.022). Baseline IOP (p = 0.022), maximum IOP (p = 0.003), and scleral rigidity (p = 0.029) were significantly associated with VD decreases in eyes with POAG. No changes were observed in VD during adduction gaze exclusively. Acute IOP elevation induced with OPD, but not adduction gaze, decreased peripapillary VD measured with OCT-A imaging. IOP levels and scleral rigidity significantly affected VD reduction in POAG patients. Thus, high scleral rigidity may decrease the ability of the globe to dampen the well-known effects of IOP fluctuation on glaucoma onset and progression. What is known Decrease vascular density in the peripapillary retina was associated with POAG, but factors related to the vascular response to elevated IOP are unexplored. What is new OCT-A quantification shows decreases in vascular density of the superficial layers of the peripapillary retina during an acute elevation in IOP. High IOP levels and scleral rigidity significantly affected vascular density reduction in POAG patients.

Effects of thermal cycles and time-dependent behavior of the deck on steel network arch bridges

Network arches are a type of arch bridges with inclined hangers, in which some hangers cross each other at least twice. This paper aims to evaluate the effects of thermal fluctuations and volumetric changes of the concrete deck on steel network arches. Fifty-nine variants of a reference network arch bridge were developed, assuming identical arch geometries but varying hanger arrangements. Each bridge was modeled using the finite element method and subjected to heat flux due to solar radiation and changes in ambient temperature in addition to heat transfer via conduction, convection, and radiation. The time-dependent deformations of the concrete deck were implemented using a rate-type formulation. Results obtained during a one-year period after the assumed end of construction showed that stress changes in the arch bridge due to ambient and time-dependent effects were not very sensitive to the hanger layout. Neglecting concrete creep and shrinkage was found to cause a 15-20% underestimation of maximum stresses in the concrete deck, whereas a 40-60% error was observed in both the deck and rib when thermal effects were ignored. The radial arrangement of hangers, already known to perform favorably under live loads, was also found to provide the smallest bending moments and the fewest number of relaxed hangers due to thermal and time-dependent effects.

Monthly, Annual and Seasonal Changes in Temperature by Using Mann Kendall and Sen’s Slope Estimator in Karnataka, India

The mean annual minimum temperature during the period 1979-2019 has increased significantly in Eastern dry zone, Southern dry zone and Southern transition zone to a cumulative of total of 0.010°C, 0.013°C and 0.08 °C respectively while it has decreased significantly in Hilly zone with a magnitude of -0.032°C. The annual maximum temperature significantly increased in North eastern transition zone (0.018°C), North eastern dry zone (0.017°C), Northern dry zone (0.014°C), Central dry zone (0.010°C), Eastern dry zone (0.011°C), Southern dry zone (0.013°C), Southern transition zone (0.016°), Northern transition zone (0.016°C) and Coastal zone (0.018°C). The hilly zone experienced a decrease in annual maximum temperature by-0.055°C. Therefore, it is evidential that, Karnataka is getting raised over the years. Researchers should develop crop varieties that are insensitive to temperature changes and scientist should develop packages of practices which will reduce adverse effect of fluctuations in climate parameters on crop productivity.

Liquid-substrate fluctuation effects on crystal growth and disordered hyperuniformity of two-dimensional materials

Liquid-substrate fluctuation effects on crystal growth and disordered hyperuniformity of two-dimensional materials

Fokker-Planck equation for the crystal-size probability density in progressive nucleation and growth with application to lognormal, Gaussian and gamma distributions

The Fokker Planck (FP) equation for the probability density function (PDF) of crystal size in phase transformations ruled by progressive nucleation and growth, has been derived. Crystals are grouped in sub-sets, we refer to as τ-crystals, where τ is the birth time of the set. It is shown that the size PDF is the superposition of the PDF of the crystal sub-sets (τ-PDFs), with weight given by the nucleation rate. The growth and diffusion coefficients entering the FP equations are estimated as a function of both τ-PDFs and nucleation rate. The functional form of these coefficients is studied for solutions of the FP equation for τ-crystals given by the lognormal, Gaussian and gamma distributions. For the first two distributions, the effect of fluctuations, nucleation rate and growth rate, on the shape of the distribution has been investigated. It is shown that for an exponential decay of the fluctuation term, the shape of the PDF is mainly governed by both the time constant for nucleation and the strength of the fluctuation. It is found that τ-PDFs given by the one-parameter gamma distributions are suitable to deal with KJMA (Kolmogorov Johnson Mehl Avrami) compliant phase transformations, where the fluctuation term is proportional to crystal size. The connection between the FP equation for the size PDF and the evolution equation for the density of crystal populations is also discussed.

Effects of primordial fluctuations on relic neutrino simulations

After decoupling, relic neutrinos traverse the evolving gravitational imhomogeneities along their trajectories. Once they turn non-relativistic, this results in a significant amplification of the anisotropies in the cosmic neutrino background (CνB). Past studies have reconstructed the phase-space distribution of relic neutrinos from the local distribution of matter (accounting for the Milky Way halo and the surrounding large-scale structures), but have neglected the CνB anisotropies in the initial conditions of neutrino trajectories. Using our previously developed N-1-body simulation framework, we show that including these primordial fluctuations in the initial conditions can be important, as it produces similar effects on the abundance and anisotropies of the CνB as the inclusion of large-scale structures beyond the Milky Way halo. Interpretability of data from future CνB observatories like PTOLEMY therefore depends on correctly modelling these effects. GitHub: our jax-accelerated simulation code can be found here.

Temperature inversion in a confined plasma atmosphere: coarse-grained effect of temperature fluctuations at its base

Prompted by the relevant problem of temperature inversion (i.e. gradient of density anti-correlated to the gradient of temperature) in astrophysics, we introduce a novel method to model a gravitationally confined multi-component collisionless plasma in contact with a fluctuating thermal boundary. We focus on systems with anti-correlated (inverted) density and temperature profiles, with applications to solar physics. The dynamics of the plasma is analytically described via the coupling of an appropriated coarse-grained distribution function and a temporally coarse-grained Vlasov dynamics. We derive a stationary solution of the system and predict the inverted density and temperature profiles of the two species for scenarios relevant for the corona. We validate our method by comparing the analytical results with kinetic numerical simulations of the plasma dynamics in the context of the two-species Hamiltonian mean-field model. Finally, we apply our theoretical framework to the problem of the temperature inversion in the solar corona, obtaining density and temperature profiles in remarkably good agreement with the observations.

Retinal Fluid and Thickness Fluctuations in Archway Trial for Port Delivery System With Ranibizumab vs Monthly Ranibizumab Injections

PurposeTo determine proportion of eyes with neovascular age-related macular degeneration (nAMD) with retinal fluid and/or central subfield thickness (CST) fluctuations and evaluate their impact on best-corrected visual acuity (BCVA) in eyes treated with the Port Delivery System with ranibizumab (PDS) versus monthly intravitreal ranibizumab injections. DesignPost-hoc analyses of phase 3 Archway trial (NCT03677934). ParticipantsAdults with nAMD responsive to anti-vascular endothelial growth factor therapy. Intervention418 patients randomized 3:2 to the PDS (100 mg/mL) with refill-exchanges every 24 weeks (Q24W) or monthly intravitreal ranibizumab (0.5 mg) for 96 weeks. OutcomesProportion of eyes in each treatment arm with subretinal and/or intraretinal fluid (SRF/IRF) overall and in central 1-mm; BCVA changes from baseline by treatment arm and fluid presence/location; proportion of eyes with CST fluctuations from baseline to week 48, week 48 to 96, and baseline to week 96; effects of CST fluctuations on BCVA. Results415 eyes were assessed. In the PDS versus monthly ranibizumab arm, proportion of eyes with SRF/IRF, central SRF, and central IRF were 47.6% versus 50.9%, 29.0% versus 19.2%, and 11.7% versus 12.6% at baseline, and 57.8% versus 56.1%, 21.6% versus 14.8%, and 7.0% versus 8.4% at week 96. BCVA changes from baseline to week 96 were –1.1 letters with the PDS versus –1.4 with monthly ranibizumab in eyes with SRF/IRF, and –1.9 versus –1.8 in eyes with central SRF. In eyes with central IRF, BCVA changes from baseline to week 96 were –2.1 with the PDS versus –6.9 with monthly ranibizumab, respectively (mean BCVA at 96 weeks 68.9 [20/40] versus 64.6 [20/50]). CST fluctuations occurred in 32.1% and 29.7% of PDS versus monthly ranibizumab eyes; corresponding BCVA changes from baseline to week 96 were –2.5 versus –2.6 (mean BCVA at 96 weeks 72.7 [20/35] versus 71.5 [20/38]). ConclusionsPDS Q24W maintained BCVA to 96 weeks regardless of SRF/IRF, central SRF, central IRF, or CST fluctuations, comparable with monthly ranibizumab, thus supporting the use of the PDS in stabilizing retinal anatomy without the need for monthly treatment in patients with nAMD.

A study on usefulness of neural network equalizer to reduce impact of amplitude fluctuations in magnetic tape

As digital data grows explosively year after year, magnetic tape devices, with their high reliability and long-term storage capacity, are widely used for backup and archiving. Magnetic tape devices with larger capacity are required, and it is necessary to improve track density. We have previously constructed a simulator that considers inter-track interference due to narrower tracks in barium ferrite (BaFe) magnetic tape drives and evaluated its performance. In this study, we develop a simulator which more accurately models the experimental data, considering amplitude fluctuations caused by the problem of poor tape running, and discuss the usefulness of a neural network equalizer to reduce the effects of amplitude fluctuations. As a result, we show that applying the neural network equalizer is useful in reducing the impact of amplitude fluctuations caused by the problem of poor tape running.

Modulation of fatty acid profiles and turnover dynamics in jellyfish polyps through copepod diets: Insights into trophic interactions and nutrient flux.

Fatty acids (FAs) are vital biomolecules crucial for determining food quality for higher trophic levels. To investigate FA transfer and turnover time in predators, we conducted a diet switch experiment using jellyfish polyps. These polyps were fed food sources including Artemia sinica nauplii and FA-manipulated copepod Pseudodiaptomus annandalei, maintained on distinct algal diets with varied FA compositions. Our findings reveal that copepods may have a strong potential to synthesize long-chain polyunsaturated FA to maintain biochemical homeostasis when consuming low-quality food. Consequently, the species-specific fatty acid composition within plankton, combined with effects of seasonal environmental fluctuations and climate change, leads to changes in the FA composition of foundational food web components. These alterations create a complex "nutrient black box" effect as they propagate up trophic levels. Our study shows that jellyfish polyps fail to accumulate EPA and DHA but display high levels of ARA compared to their zooplankton and phytoplankton food sources, suggesting a potential association with dietary EPA and DHA through an unidentified pathway. Certain FA components indicate variations in the turnover time when polyps undergo a dietary shift. Understanding the trajectory of FA metabolism across the "phytoplankton-zooplankton" interface, along with its turnover time, provides crucial insights for modeling diet estimation of components within food webs.

Time resolution of wind speed data introduces errors in wind power density assessment

Wind energy is critical in the global shift towards renewable energy sources, necessitating accurate potential assessments for informed decision-making and strategic development in this transition. Despite the widespread use of wind speed data with varying time resolutions for estimating wind energy, the influence of this variability on the accuracy of wind energy assessment remains uncertain. In this study, we investigate the impact of wind speed data’s time resolution on wind power density (WPD) assessment, utilizing high-frequency, in-situ observations collected from eight anemometer towers in China. Through analysis of wind speed data at nine resolutions, ranging from 10-minute to monthly intervals, we uncover significant errors introduced by coarser time resolutions in WPD calculations. Specifically, it reveals a systematic underestimation of WPD with decreasing time resolution, highlighting the importance of time resolution in wind energy evaluation. While hourly wind speed data yield acceptable WPD errors, daily and monthly resolutions lead to substantial underestimation due to the smoothing effect of fluctuations. We also delve into the underlying mechanisms contributing to these errors, including variations in the power law exponent and changes in the Weibull distribution shape factor with time resolution. Furthermore, we propose a novel method to mitigate WPD calculation errors using coarse time resolution data by regressing Weibull distribution factors. The findings offer valuable insights into wind speed data selection and accurate wind energy assessment, with implications for renewable energy planning and policy-making in the context of the global energy transition.

The Fluctuation Effect of Remnant Polarization in Hf₀.₅Zr₀.₅O₂ Capacitors at Elevated Temperatures

The Fluctuation Effect of Remnant Polarization in Hf₀.₅Zr₀.₅O₂ Capacitors at Elevated Temperatures

Numerical analysis of oil liquid sloshing in fuel tanks of plug-in hybrid electric vehicles under different structure baffles

Abstract To solve a large amount of oil liquid sloshing in the fuel tank and a series of problems caused by oil liquid sloshing in the plug-in hybrid electric vehicle (PHEV) under the condition of electric drive only, this paper analyzes the oil liquid sloshing in fuel tank under different liquid filling rates under complex situations. After determining the representative liquid filling rates, the optimal scheme is finally determined. We conduct the specific analysis of different types, structures, and installation modes of fuel tank baffles under the same working conditions and liquid filling amount. The results show that the less liquid is filled in the fuel tank, the larger the sloshing amplitude is, and the more complicated the sloshing situation is. When the oil liquid sloshes, the non-porous baffle has an obvious zoning effect on the oil liquid and suppresses the oil liquid fluctuations effect, but the oil liquid fluidity is poor. The angle between the linear baffle and the oil liquid flow direction is larger, which has a better attenuation effect on the impact force of oil liquid. In conditions of significant oil liquid sloshing, a high baffle enhances the contact area of the oil liquid, resulting in improved inhibition effects. After considering various advantages and disadvantages, the analysis of the cruciform baffle found that the cruciform baffle limited the multi-directional movement of oil liquid, caused substantial vortex inside the oil liquid, and attenuated the kinetic energy generated by oil liquid sloshing. This greatly reduced the impact of the oil liquid on the fuel tank wall and improved the effect of suppressing oil liquid fluctuations.

Fluctuation-driven dynamics of liquid nano-threads with external hydrodynamic perturbations

Instability and rupture dynamics of a liquid nano-thread, subjected to external hydrodynamic perturbations, are captured by a stochastic lubrication equation (SLE) incorporating thermal fluctuations via Gaussian white noise. Linear instability analysis of the SLE is conducted to derive the spectra and distribution functions of thermal capillary waves influenced by external perturbations and thermal fluctuations. The SLE is also solved numerically using a second-order finite difference method with a correlated noise model. Both theoretical and numerical solutions, validated through molecular dynamics, indicate that surface tension forces due to specific external perturbations overcome the random effects of thermal fluctuations, determining both the thermal capillary waves and the evolution of perturbation growth. The results also show two distinct regimes: (i) the hydrodynamic regime, where external perturbations dominate, leading to uniform ruptures, and (ii) the thermal-fluctuation regime, where external perturbations are surpassed by thermal fluctuations, resulting in non-uniform ruptures. The transition between these regimes, modelled by a criterion developed from linear instability theory, exhibits a strong dependence on the amplitudes and wavenumbers of the external perturbations.

40Ar/39Ar geochronologic and paleoenvironmental constraints to glacial termination III and MIS 7e, 7c, and 7a sea level fluctuations on the Tyrrhenian Sea coast of Italy

We provide detailed sedimentological, paleontological, and tephrochronological data on a complex sedimentary succession cropping out in the Tyrrhenian coastal area of central Italy, which was deposited in response to sea-level rise during MIS 7, coeval with the Latera phase of activity in the Vulsini Volcanic District. Diffuse intercalations of primary volcanic layers erupted during this phase and their geochronologic and chemostratigraphical characterization based on 40Ar/39Ar dating and EMP analyses, allowed for the identification of three stacked aggradational successions separated by erosive phases and their correlation with the Oxygen isotope record and phases in the relative sea-level curve. The ages of the tephra layers strictly frame the sedimentation in the interval of 253–206 ka, providing independent dating to glacial Termination III and to the three sea-level oscillations during MIS 7e, 7c, and 7a.Moreover, micro- and macrofaunal-based analyses provide information on the paleoenvironments and bathymetry during the highstands, which complement the geomorphological analysis reconstructing the inner edges of the corresponding marine terraces, allowing us to assess precise maximum sea level reached during MIS 7e and MIS 7a.The results of this multidisciplinary study enable us to establish in great detail the chronology, dynamics, relative amplitude, and effects of the sea-level fluctuations in the Tyrrhenian Sea during the whole MIS 7, providing independent, precise geochronological constraints for this period.

Influence analysis of position error to the operating characteristics of opposed-piston free-piston engine generator with position observation optimization

Stable operation is a crucial challenge for opposed-piston free-piston engine generator (FPEG). Due to the absence of mechanical constraints, variations position-based operation parameters would have a significantly impact on the operation performance of the system. This paper conducted a comprehensive investigation into the effects of position fluctuations on the system's dynamic characteristics and thermodynamic performance by leveraging a detail system model with stable operation. Additionally, a novel real-time position observation approach for the mover was proposed, leveraging observation coils. The findings indicate that the opposed-piston FPEG system can quickly recover to stable operational state within a few cycles for a one-time position error, if there is no misfire in the power cylinder. The acceptable range for stable operation of the opposed-piston FPEG is between +35 % and −48 % for the one-time position error. With the continuous position error varying from +20 % to −30 %, there is a noticeable decrease in the compression ratio, operating frequency, and overall system performance. A significant linear relationship has been found between the flux linkage value of the observation coil and the position of the mover. The maximum difference between the observed position calculated by the proposed approach and the actual position was below 4 %.

Enhanced capability of model fitting to nuclear level density and heat capacity: testing on 93−98Mo nuclei

We propose an improved fitting approach that improves reliability in studying the nuclear level density (NLD) and thermodynamic quantities. The proposed method, which relies on the fact that experimental fluctuations or outliers, if they exist, should not be involved in the fitting process, is validated with a set of data artificially generated with anomalous data points being intentionally inserted. In order to showcase the advantages of the proposed technique, we have applied it to re-investigate the back-shifted Fermi gas (BSFG) level density parameters and thermodynamic quantities, particularly the heat capacities, of 93−98Mo isotopes. We have found that the range of values for the level density parameter of 93Mo (approximately from 8.5 to 9.0 MeV−1) is notably smaller than that obtained for the other isotopes of Mo (approximately from 10.5 to 11.5 MeV−1). This observation is different from previous predictions, in which the values of level density parameter of all Mo isotopes are in the same range. This is because among the Mo isotopes under examination, 93Mo (N = 51 neutrons) has the smallest number of valence neutrons, namely only a single neutron away from the closed N = 50 shell. In addition, thanks to the proposed method, we have discussed the effects of data fluctuations on the BSFG NLDs and thermodynamic quantities of 93−98Mo isotopes, from which our recommendation for future works is announced. On top of that, we should notice that the proposed approach can be further applied to any work involving the fitting of a phenomenological model to empirical data.

Effects of groundwater level changes on soil characteristics and vegetation response in arid and semiarid coal mining areas.

Coal mining in arid and semiarid regions often leads to numerous ecological and environmental problems, such as aquifer depletion, lake shrinkage, vegetation degradation, and surface desertification. The drainage from coal mining activities is a major driving force in the evolution of the groundwater-soil-vegetation system. In order to explore the effect of groundwater level fluctuation on soil properties and the response mechanism of surface vegetation in coal mining areas, this study is based on hydrogeological and ecological vegetation investigations in the Bojianghaizi Basin, and soil and vegetation samples are collected in the areas with different groundwater levels, and soil and vegetation indexes are analyzed with the aid of methods such as numerical statistics, linear regression, and correlation analysis with the aid of the Origin software. The results show that there is a significant negative correlation between groundwater table (GWT) and soil water content (SWC), soil conductivity, soil organic matter (SOM), soil available nitrogen (SAN), and soil available potassium (SAK). Mining activities have led to the destruction of the soil structure, greatly reducing its ability to retain water and fertilizer. The contents of SWC, SOM, and SAN in the mining area are significantly reduced, which are at least 49.73%, 47.56% and 59.90% lower than those around the mining area. On the northern and southern sides of the lake, serious soil salinization exists in the lakeshore zone where the depth to the water table is <0.5m, and the water required for the growth of vegetation here mainly comes from the groundwater, so there are only a few water-loving and saline-resistant plants; when the depth to the water table is 0.5-7m, the growth of surface vegetation is influenced by the double impacts of the water table and atmospheric precipitation with a high degree of species richness; when the depth to the water table is >7m, the surface vegetation is only dependent on the limited atmospheric precipitation for water. When the depth of groundwater is >7m, the surface vegetation only relies on limited atmospheric precipitation for water, and drought-tolerant plants mainly grow in these areas. This study not only provides a scientific basis for the sustainable development and environmental protection of similar mines in the world, but also has important significance in guiding the ecological management and rational utilization of water resources in coal mine areas. What is more, This study provides valuable insights into sustainable water resource management in arid and semi-arid regions, crucial for mitigating the ecological impacts of coal mining activities.

Properties of the connected components in projections of random bipartite networks: effects of clique size fluctuations

Projection is a helpful description for treating bipartite networks as (monopartite) networks with pairwise interactions. Projections induce correlation spontaneously, avoiding negative degree correlation, even if bipartite networks are entirely random. In this study, we examined the structure of projections of random bipartite networks characterized by the degree distribution of individual and group nodes through the generating function method. We decomposed a projection into two subgraphs, the giant component, and finite components and analyzed their degree correlation. We demonstrate that positive degree correlations in projections originating from the clique size fluctuation remain after the decomposition at the set of finite components, although the values of their clustering coefficient are still finite. The giant component can exhibit either positive or negative degree correlations based on the structure of the projection. However, they are positively correlated in most cases. In addition, we found that a projection removed the giant component coincides with one in the subcritical phase, i.e., the discrete duality relation, when the degree distributions for group and individual are of Poisson.

Characteristics of Mould Growth in Pine and Spruce Sapwood and Heartwood under Fluctuating Humidity

The importance of maintaining a healthy indoor climate has recently increased, as has the durability of building structures, and for this issue, we need to predict mould growth. To prepare this model under real conditions is challenging, and this work aimed to contribute data to this model. This article presents the findings of a laboratory study investigating the effects of fluctuations in the relative humidity and temperature conditions on mould growth on pine and spruce. The study compared the results to a previous steady-state experiment, demonstrating that fluctuations in relative humidity and temperature prolonged the onset of mould growth. The mould growth observed depended on the type of wood with pine or spruce wood exhibiting different growth patterns compared to heartwood or sapwood. In sapwood, mould growth was found to be almost independent of the direction of the fiber. The first microscopic indications of mould growth on pine sapwood were observed around day 76, with the first macroscopic indications observed around day 90. On the contrary, spruce sapwood demonstrated a limit for mould growth. The mould growth was only visible under the microscope with the first indications observed between the 72nd and 80th day. Furthermore, heartwood was found to be unsuitable for mould growth under fluctuating conditions.