Effects Of Sudden Changes Research Articles

Hemolymph Agglutination and Coagulation Inside the Body of Penaeus monodon (Crustacea, Decapod) and Effect of Sudden Changes of Salinity on Oxygen Consumption and Metabolic Rate

Hemolymph Agglutination and Coagulation Inside the Body of Penaeus monodon (Crustacea, Decapod) and Effect of Sudden Changes of Salinity on Oxygen Consumption and Metabolic Rate

Asymmetric effects of sudden changes in timbre on auditory stream segregation

Two experiments explored the effects of abrupt transitions in timbral properties [amplitude modulation (AM), pure tones vs narrow-band noises, and attack/decay envelope] on streaming. Listeners reported continuously the number of streams heard during 18-s-long alternating low- and high-frequency (LHL–) sequences (frequency separation: 2–6 semitones) that underwent a coherent transition at 6 s or remained unchanged. In experiment 1, triplets comprised unmodulated pure tones or 100%-depth AM was created using narrowly spaced tone pairs (dyads: 30- or 50-Hz modulation). In experiment 2, triplets comprised narrow-band noises, dyads, or pure tones with quasi-trapezoidal envelopes (10/80/10 ms), fast attacks and slow decays (10/90 ms), or vice versa (90/10 ms). Abrupt transitions led to direction-dependent changes in stream segregation. Transitions from modulated to unmodulated (or slower-modulated) tones, from noise bands to pure tones, or from slow- to fast-attack tones typically caused substantial loss of segregation (resetting), whereas transitions in the opposite direction mostly caused less or no resetting. Furthermore, for the smallest frequency separation, transitions in the latter direction usually led to increased segregation (overshoot). Overall, the results are reminiscent of the perceptual asymmetries found in auditory search for targets with or without a salient additional feature (or greater activation of that feature).

Effects of sudden changes in strain rate on hot deformation behavior of Inconel 718

Effects of sudden changes in strain rate on hot deformation behavior of Inconel 718

The impact of the learning environment sudden shifts on students’ performance in the context of the COVID-19 pandemic

IntroductionThis study aims to determine the effect of sudden changes in learning environments on students’ performance, in the context of the COVID-19 pandemic lockdown. We present an analysis of the kinesiology program, focusing on the learning modality changes through the years, and its impact on students’ performance. MethodsWe analyzed three periods over five years. During the Pre-pandemic period (2018-2019), classes had been taught in-person, during the pandemic (2020-2021) classes had been taught online, and during end of lockdown (2022) classes had return to in-person modality. In addition, we also examined the academic performance outcomes by gender during the three periods. ResultsWe found that the academic performance significantly increased in all cohort of career, increasing the average grade from 4.7±0.08 (2018 to 2019, in-person) to 5.15±0.07 during the pandemic period, from 2020 to 2021, when online modality was utilized. Furthermore, when returning to in-person classes in 2022, the academic performance reduced significantly to 4.6±0.17. We also found that gender did not have an influence on academic performance in any of the learning environments presented. However, during clinical internships, we found that gender had a significantly effect on academic performance. ConclusionBased on these results, we conclude that the sudden shift from in-person learning to online learning modality helped improved the learning performance of student, reflecting those results on better students’ performance scores that could be associated with the enhanced efficient use of time.

Reef recovery and resilience: interpreting abiotic effects on critical early life stages of large brown algae

Rocky reefs throughout the temperate zone are dominated by large brown algae, which are major foundation species and ecosystem engineers. There is usually an ecological bottleneck at the early life stage of such algae when they are vulnerable to a wide range of stressors. A large earthquake that affected the coastline of southern New Zealand highlighted the combined effects of sudden changes to multiple stressors on large algal assemblages. In particular, the regime of temperature, sediment and light suddenly changed as the coastal platform was lifted, and sediments from the catchment occluded the light environment of nearshore waters. Here we tested the effects of these stressors on early survival and growth of 3 formerly dominant species—the fucoids Landsburgia quercifolia and Durvillaea antarctica and the laminarian Lessonia variegata—over 100 d using a culture laboratory. After 42 d, interactive effects were found for growth of all species. Decreasing light and increasing temperature had the greatest negative effect on L. variegata and D. antarctica growth. Growth was minimal at the lowest light treatment (PAR: 16 µmol m-2 s-1) for all species, but often least growth was found at the highest sediment treatment (PAR: 32 µmol m-2 s-1). L. quercifolia was resilient to increasing temperature, whereas survival and growth decreased with increasing temperature for D. antarctica and L. variegata. These results are highly suggestive of the coincident influences of major stressors on the post-earthquake marine ecosystem. These results also highlight that recovery of large brown algae following disturbance events is likely to be slow due to an increase in coastal sedimentation and extreme water temperature.

Design of temporary, conditional, general and highly influential buildings for tropical cyclones and severe local storms

This paper first discusses the causes of damage to buildings and structures due to various types of winds including daily winds and some extremely strong winds. Regarding devastating wind-induced disasters due to tropical cyclones (TC), the importance of combined effects of wind and water hazards is emphasized. It also points out human errors hidden in damage scenarios, especially for large buildings. The importance of cladding/component design, the significance of debris impacts, and the effects of sudden changes in internal pressures are also emphasized. The design principles for buildings and structures are also examined, and the crucial differences among building performances against TCs and severe local storms such as tornadoes and downbursts are discussed. Design load levels for temporary buildings including scaffoldings and construction offices and for conditional buildings and structures including cranes, movable roofs and so on are also discussed. Next, design issues of tornado effects on highly important and highly influential buildings such as nuclear power plants are discussed. Finally, to cope with the future increasing trend of wind-related disasters, the importance of decarbonization and full-scale storm simulators are emphasized.

Effects of sudden change in wind loads on running performance of trains on a highway-railway one-story bridge in crosswinds

Effects of sudden change in wind loads on running performance of trains on a highway-railway one-story bridge in crosswinds

Numerical study on the effect of sudden change in coal property on coal and gas outburst during roadway excavation

Numerical study on the effect of sudden change in coal property on coal and gas outburst during roadway excavation

Performance Assessment of Hetero-Junction Intrinsic Thin Film HIT Photovoltaic Module Using Machine Learning Methods

A solar cell built of ultra-thin amorphous silicon and high-quality mono-crystalline silicon is known as a hetero-junction intrinsic thin film. It has a pyramid surface on the front that increases sunlight absorption. The operating environment has a significant impact on the performance of hetero-junction intrinsic thin-film photovoltaic modules with real I–V (current-voltage) characteristics. Changes in the environment have a significant impact on solar irradiation. Clouds also have a significant impact on the solar irradiation that a PV cell receives. In this project, we will use the Random Forest Regression machine learning algorithm to investigate the effects of sudden changes in environmental conditions on power output and module temperature of an HIT (Heterojunction with Intrinsic Thin Layer) module, where irradiance, temperature, and module efficiency parameters are taken into account when designing modules. The algorithm’s output will be studied to gain a better understanding of performance variations as well as the behavior of the power output and module temperature when subjected to random influences induced by various environmental variables. The suggested algorithm is not restricted to a certain module technology or geographic location.

Anticipatory Drainage Base Management for Groundwater Level Optimization

AbstractControlled drainage is normally operated on a seasonal timescale to increase availability of water and to limit nutrient loss to surface water. It is conceivable that with more frequent, or even daily, management of the drainage base, controlled drainage can be both more efficient and effective. With the analytical successive steady state model presented here, rapid simulations of groundwater level and discharge as a function of time for a field under either regular or controlled drainage are feasible. The model includes effects of sudden changes in drainage base as well as damping and attenuation of dynamics by the unsaturated zone. It is validated against a numerical model and shows good agreement with numerical results. We demonstrate how this analytical model may facilitate anticipatory drainage base management based on ensemble weather forecasts, such that groundwater levels can be maintained at a theoretical optimal level.

Long-Distance Transport of Finisher Pigs in the Iberian Peninsula: Effects of Season on Thermal and Enthalpy Conditions, Welfare Indicators and Meat pH.

Simple SummaryLong-distance transport in the global swine industry is more the rule than the exception. We tested the impact on the rates of temperature change and air enthalpy on the stress response and muscle pH in pigs subjected to long-distance travel from Spain to Portugal performed in the summer and winter. We found that winter journeys are more adverse for the animals because during the journey, abrupt variations in rates of temperature change and air enthalpy caused a marked physiological stress response and effects on the meat pH after 45 min. These results indicate the need to develop new environmental control strategies that mitigate abrupt temperature changes during travel to attenuate the biological cost of such long-distance transport on the animals.Current legislation in the European Union places limits on live pig transport according to outside temperature, but less is known about the effects of sudden changes in the thermal microenvironment in trailers, particularly during long-distance transport. In this study, we measured the temperature and relative humidity inside livestock vehicles carrying 1920 Spanish finisher pigs (live weight 100 kg and 240 animals per journey) during eight long-distance (>15 h) commercial journeys to slaughter from northern Spain to Portugal in the summer and winter. Here, we report the rate of change in the air temperature (°C × min−1) and air enthalpies in the transport vehicle (kg water kg dry air-1). At sticking, blood samples were taken for to measure cortisol, glucose, and creatine kinase (CK) as stress response indicators, and the meat pH after 45 min and the pH after 24 h were also determined. The rate of change in the air temperature and enthalpy was higher inside the livestock vehicle during the winter months and was positively related with higher cortisol and glucose levels and lower pH after 45 min (p < 0.05). It is proposed that the rate of temperature change and air enthalpy represent useful integrated indices of thermal stress for pigs during transport.

The dynamics of auditory stream segregation: Effects of sudden changes in frequency, level, or modulation.

Three experiments explored the effects of abrupt changes in stimulus properties on streaming dynamics. Listeners monitored 20-s-long low- and high-frequency (LHL-) tone sequences and reported the number of streams heard throughout. Experiments 1 and 2 used pure tones and examined the effects of changing triplet base frequency and level, respectively. Abrupt changes in base frequency (±3-12 semitones) caused significant magnitude-related falls in segregation (resetting), regardless of transition direction, but an asymmetry occurred for changes in level (±12 dB). Rising-level transitions usually decreased segregation significantly, whereas falling-level transitions had little or no effect. Experiment 3 used pure tones (unmodulated) and narrowly spaced (±25 Hz) tone pairs (dyads); the two evoke similar excitation patterns, but dyads are strongly modulated with a distinctive timbre. Dyad-only sequences induced a strongly segregated percept, limiting scope for further build-up. Alternation between groups of pure tones and dyads produced large, asymmetric changes in streaming. Dyad-to-pure transitions caused substantial resetting, but pure-to-dyad transitions sometimes elicited even greater segregation than for the corresponding interval in dyad-only sequences (overshoot). The results indicate that abrupt changes in timbre can strongly affect the likelihood of stream segregation without introducing significant peripheral-channeling cues. These asymmetric effects of transition direction are reminiscent of subtractive adaptation in vision.

Season specific influence of projected ocean changes on the response to cadmium of stress-related genes in Mytilus galloprovincialis

Anthropogenic inputs of carbon dioxide in the atmosphere are driving ocean warming and acidification. The potential threat represented by these changes for marine species could be amplified in coastal areas, characterized by higher levels of pollutants. In addition, temperate organisms may exhibit a different seasonal tolerance to stressors influenced by fluctuations of environmental and physiological factors. In this study, Mediterranean mussels Mytilus galloprovincialis collected both in summer and winter were exposed to combinations of two temperatures (SST, seasonal surface temperature and SST+5 °C) and two levels of pH (8.20 and 7.40) in clean or cadmium contaminated seawater (20 μg/L Cd). mRNA levels of genes related to metal-induced stress response were investigated, including metallothionein mt-20, heat-shock protein hsp70, superoxide dismutase Cu/Zn-sod, catalase cat, glutathione peroxidase gpx1 and glutathione S-transferase gst-pi. To further elucidate if tissues with different physiological roles could exhibit different responsiveness, such analyses were carried out in digestive gland and in gills of exposed mussels. mt-20 mRNA increase after Cd-exposure was higher in the digestive gland than in the gills, with few modulations by temperature or pH only in the latter. Acidification, alone or in combination with other stressors, increased hsp70 mRNA, with seasonal- and tissue-specificities (higher in summer and in digestive gland). Among antioxidants, gpx1 mRNA was affected by Cd in both tissues and seasons, with further modulations due to pH and temperature variation tissue- and season-specific; in winter the combination of Cd, warming and acidification affected Cu/Zn-sod both in digestive gland and gills and cat only in gills, while weak seasonal variations were observed for gst-pi transcripts only in digestive gland. The overall results highlighted the importance of considering seasonality and responsiveness of different tissues to predict the effects of sudden changes in environmental parameters on responsiveness to and toxicity of chemicals in marine coastal organisms.

Effects of Sudden Drop in Salinity on Osmotic Pressure Regulation and Antioxidant Defense Mechanism of Scapharca subcrenata.

Salinity is an important ecological factor that impacts the growth and survival of aquatic organisms. The salinity of seawater in coastal and estuarine areas is often subject to dynamic changes because of seasonal rainfall and continental runoff. Thus, the current study investigated the effects of sudden changes in salinity on the survival rate and osmotic pressure regulation mechanisms of bottom-sowing seedlings of the economically important ark shell, Scapharca subcrenata. By simulating the sudden changes that occur in seawater salinity after rainstorms, the results showed that the osmotic pressure of the hemolymph and Na+, K+, Ca2+, and Cl– concentrations first decreased and then increased. When the salinity decreased from 30 to 14‰, hemoglobin, soluble total protein, taurine, and total free amino acid gradually increased; maximum levels of hemoglobin, soluble total protein, and taurine occurred once the salinity increased to 22‰ at 96 h. After 96 h, the total free amino acid content increased until 144 h. The reactive oxygen species (ROS) content and total antioxidant capacity (T-AOC) peaked at 96 h, whereas the expression levels of Mn-superoxide dismutase (MnSOD) and catalase (CAT) increased earlier, indicating that, with continuous ROS generation, antioxidant defense mechanisms were activated to avoid oxidative damage. Expression levels of cathepsin C (CTSC), cathepsin D (CTSD), heat shock protein 20 (HSP20), and heat shock protein 70 (HSP70) were significantly higher than in the control group at 48 h (salinity level 14‰); the expression levels of HSP20, heat shock protein 90 (HSP90), MnSOD, and glutathione peroxidase (GPx) remained high, indicating that they were still required for osmotic pressure regulation to maintain the dynamic balance between the generation and removal of ROS as the salinity level increased. These results not only add to our basic understanding of the aquatic ecology of S. subcrenata, but also provide a theoretical ground for improving the survival rate of bottom-sowing, propagation, and release of S. subcrenata seedlings.

The Effect of Environmental Conditions on the Degradation Behavior of Biomass Pellets.

Biomass pellets provide a pivotal opportunity in promising energy transition scenarios as a renewable source of energy. A large share of the current utilization of pellets is facilitated by intensive global trade operations. Considering the long distance between the production site and the end-user locations, pellets may face fluctuating storage conditions, resulting in their physical and chemical degradation. We tested the effect of different storage conditions, from freezing temperatures (−19 °C) to high temperature (40 °C) and humidity conditions (85% relative humidity), on the physicochemical properties of untreated and torrefied biomass pellets. Moreover, the effect of sudden changes in the storage conditions on pellet properties was studied by moving the pellets from the freezing to the high temperature and relative humidity conditions and vice versa. The results show that, although storage at one controlled temperature and RH may degrade the pellets, a change in the temperature and relative humidity results in higher degradation in terms of higher moisture uptake and lower mechanical strength.

Overriding Plate Velocity Control on Surface Topography in 2‐D Models of Subduction Zones

AbstractWe study the dynamically induced flexural topography in subduction numerical mechanical models. We focus on the topographic changes at the overriding plate (OP) surface induced by variations in OP kinematics, particularly when the subducting plate (SP) has a stationary motion after having reached the rigid base of the upper mantle. Our models consist of two viscoelastic plates with free surfaces and an isoviscous mantle. Friction is imposed along the planar subduction interface. We first characterize the main topographic features at a constant OP velocity, using spatial definitions based on geometrical estimations of the volcanic arc position. The models exhibit the formation of a bulge in the forearc area followed landwards by a depression and a smaller second bulge, both bracketing the arc region. The steady‐state distance to the trench of these features increases with OP velocity. Their amplitude is affected by the far‐field OP tectonic regime that depends on kinematics, and plates and subduction interface strength. We next test the effect of sudden changes in OP velocity. An OP acceleration yields a transient topographic tilt, during which the outer forearc quickly subsides whereas the arc region uplifts, and that is followed by reverse slower motions. An OP slowdown induces opposite motions. The rates of elevation change during the tilt are approximately proportional to velocity variations and mainly sensitive to the SP strength. The rates are higher than 0.1 mm/yr for velocity changes higher than 1 cm/yr. We suggest that topographic accommodations of OP velocity changes should be considered when quantifying nonisostatic topography.

Cyber security of electric networks with energy storages

Modern Energy Power Systems (EPS) are characterized by a rather high share of distributed generation, renewable energy sources (RES) and energy storage systems (ESS) operating under the control of smart devices. For transition to a qualitatively new level of power industry management, the developed countries create Smart Grids. An effect of sudden changes of loads, power flows in the lines, and changes in the generation, as well as other unexpected factors can negatively affect on stability and reliability of state of EPS as well as lower EPS flexibility that is one of the most relevant features of future energy systems. Use of ESS is one of the recognized options of maintaining the energy system flexibility. At the same time executing energy storages at an energy object and, moreover, their coordination using Internet-technologies globally increase cyber vulnerability of electrical network. At this paper different aspects of cyber security of electrical networks with energy storage units incorporated into them are shown and ways of their cyber resilience are considered. By arranging PMUs in power system nodes using ESS, awareness of the absence of cyber attacks can be increased.

Coordinated Control of PV-Ultracapacitor System for Enhanced Operation Under Variable Solar Irradiance and Short-Term Voltage Dips

Utilization of an ultracapacitor (UC)-based energy storage device can provide one of the most efficient solutions for short-term operational challenges in grid-connected photovoltaic (PV) systems. This paper proposes an algorithm for coordinated control of PV and ultracapacitor-based energy storage system to minimize the effects of sudden changes in solar irradiance and the presence of low voltages at the point of common coupling. In addition, this work proposes an improved multi-mode operational scheme for control of an ultracapacitor-based energy storage system that takes into consideration various associated limits during charging and discharging modes. The effectiveness of the proposed algorithm in mitigating the impacts of low voltages and short term changes in irradiance is demonstrated using simulation analysis carried out on the modified Consortium for Electric Reliability Technology Solutions (CERTS) microgrid testbed.

THE INFLUENCE OF HYPOTHERMIA ON THE PARAMETERS OF THE ELECTROMYOGRAM AT LOW MUSCLE TONE STATE

Effects of sudden changes in temperature on the general state of functional systems of the body can be assessed by the effects of local cold expesure on the neuromuscular system. Aim: to study electromyograms of the retracting muscle flexor of the little finger with weak static muscle tension (F1 = 50 N) during cold exposure. Methods. Altogether, 15 men aged 20-27 years participated in the study. We used one of the stochastic methods in the form of calculation of matrices of paired comparisons of electromyogram samples as an indicator of k pairs of matches of samples. Matrices of paired comparisons of samples were calculated for each test subject at a static voltage F1 = 50 N before and after local cold exposure. At the same time built a quasi-attractor dynamics, the behavior of x(t) and determined area of the quasi-attractor. In the end, the analysis of the state of the muscles of the subjects in the development of static force F was carried out on the basis of a comparison of the area of quasi-attractors in the form of S. Results. With weak (F1 = 50 N) static force after cold exposure, the area of quasi-attractor increased by 2.5 times, while in the matrices of paired comparisons of samples after local cold exposure, the number of matches of pairs of samples increased from 8 to 14. Conclusion: the regularities of changes in the number of matches of pairs of samples k in the matrices of paired comparisons with changes in the static force and under the influence of local cold exposure were revealed; statistically significant differences were found for such samples k and S before and after hypothermia.

Sliding window correlation analysis: Modulating window shape for dynamic brain connectivity in resting state

The sliding window correlation (SWC) analysis is a straightforward and common approach for evaluating dynamic functional connectivity. Despite the fact that sliding window analyses have been long used, there are still considerable technical issues associated with the approach. A great effort has recently been dedicated to investigate the window setting effects on dynamic connectivity estimation. In this direction, tapered windows have been proposed to alleviate the effect of sudden changes associated with the edges of rectangular windows. Nevertheless, the majority of the windows exploited to estimate brain connectivity tend to suppress dynamic correlations, especially those with faster variations over time. Here, we introduced a window named modulated rectangular (mRect) to address the suppressing effect associated with the conventional windows. We provided a frequency domain analysis using simulated time series to investigate how sliding window analysis (using the regular window functions, e.g. rectangular and tapered windows) may lead to unwanted spectral modulations, and then we showed how this issue can be alleviated through the mRect window. Moreover, we created simulated dynamic network data with altering states over time using simulated fMRI time series, to examine the performance of different windows in tracking network states. We quantified the state identification rate of different window functions through the Jaccard index, and observed superior performance of the mRect window compared to the conventional window functions. Overall, the proposed window function provides an approach that improves SWC estimations, and thus the subsequent inferences and interpretations based on the connectivity network analyses.