Dynamical Variables Research Articles

Variability of the Bottom Boundary Layer Induced by the Dynamics of the Cross‐Isobath Transport Over a Variable Shelf

AbstractThe bottom boundary layer (BBL) dynamics play an important role in regulating the energy, momentum balance, and circulation in the shallow shelf areas. Unlike previous studies that disconnected BBL with background variable shelf circulation, we investigate the dynamic connection between the wind‐driven shelf circulation and BBL dynamics, and show the spatial characteristics of BBL dynamics in response to three‐dimensional (3D) heterogeneous transport over the highly variable shelf topography in the Northern South China Sea. Our process‐oriented modeling study demonstrates that the mixing dynamics and upslope buoyancy transport over varying shelf topography alter the spatial variability of BBL dynamics. Driven by southwesterly upwelling‐favorable winds, the along‐shelf current generated a frictional upslope Ekman transport. The along‐isobath pressure gradient force () formed by the flow‐topography interactions over the meandering shelf induces the geostrophic cross‐isobath transport. The downwave (upwave) enhances (offset) the frictional upslope transport over the east (west) of the shelf that has a concaving (uniform) bottom topography. Over the eastern shelf with concave isobaths, the intensified and upslope cross‐isobath dense water transport strengthen stratification and weaken the effect of bottom stress‐induced mixing, limiting the development of the BBL. The antithesis occurs over the western shelf, where a small bottom stress controls the BBL. River discharge and the tidal current modulate the alongshore current, upslope transport, bottom stress intensity, and BBL development. We model the trajectory of seabed particles as they respond to the BBL dynamic regimes, and find that high (low) concentration, short (long) suspension time, and strong (weak) shoreward transport occurover the eastern (western) shelf, respectively.

Carbon dioxide and methane fluxes in the growing and non-growing season in the Dajiuhu subtropical peatland: A five-year measurement using the eddy covariance technique

Peatlands present substantial terrestrial carbon reservoirs actively engaged in land-atmosphere carbon exchanges. Ongoing variations in carbon dynamics, attributed to global climate change, underscore the necessity of elucidating the connections between carbon fluxes and meteorological parameters. Limited studies have delved into disparities in carbon fluxes and the mechanisms mediating them during growing and non-growing seasons on a long-term scale, particularly in subtropical peatlands. Consequently, this study utilized the eddy covariance technique in the Dajiuhu peatland to investigate five-year CH4 and CO2 fluxes, longside meteorological characteristics. The Dajiuhu peatland functioned as a CO2 sink and CH4 source, ultimately serving as a carbon sink. A substantial portion of the annual fluxes was measured during the non-growing season, with elevated CO2 uptake and CH4 emission during the growing season. Further analyses revealed that photosynthetically active radiation (PAR), soil temperature (Ts), air temperature (Ta), and soil water content (SWC) were critical environmental parameters influencing fluctuations in CO2 and CH4 fluxes. Two distinct controlling pathways for CO2 fluxes were identified. In the growing season, PAR emerged as the most influential factor in CO2 flux variations, and increasing Ts weakened CO2 absorption by decreasing SWC. During the non-growing season, Ts emerged as the most influential factor in CO2 exchanges, with lower Ts leading to decreased CO2 uptake. Additionally, CH4 flux variations were significantly regulated by PAR and Ts in both periods. The results illustrated that vascular plants played a pivotal role in the dynamics of carbon between peatlands and the atmosphere. Furthermore, it was discovered that the Dajiuhu peatland contributed to mitigating global warming in both the short and long term, with SGWP identified as a more reliable evaluation index. Our findings underscore the essential ecological function of the Dajiuhu subtropical peatland and provide a theoretical foundation for scientifically managing carbon in natural subtropical peatlands.

Google trends as an early indicator of African swine fever outbreaks in Southeast Asia.

African Swine Fever (ASF) is a reportable disease of swine that causes far-reaching losses to affected countries and regions. Early detection is critically important to contain and mitigate the impact of ASF outbreaks, for which timely available data is essential. This research examines the potential use of Google Trends data as an early indicator of ASF outbreaks in Southeast Asia, focusing on the three largest swine producing countries, namely, Vietnam, the Philippines, and Thailand. Cross-correlation and Kullback-Leibler (KL) divergence indicators were used to evaluate the association between Google search trends and the number of ASF outbreaks reported. Our analysis indicate strong and moderate correlations between Google search trends and number of ASF outbreaks reported in Vietnam and the Philippines, respectively. In contrast, Thailand, the country of this group in which outbreaks were reported last, exhibits the weakest correlation (KL = 2.64), highlighting variations in public awareness and disease dynamics. These findings suggest that Google search trends are valuable for early detection of ASF. As the disease becomes endemic, integrating trends with other epidemiological data may support the design and implementation of surveillance strategies for transboundary animal diseases in Southeast Asia.

Macroeconomic factors influencing the Saudi balance of payments’ current account dynamics from 1995 to 2019

Reliable development reports highlight persistent deficits in developing countries’ balance of payments since the 1980s and 1990s, attributed to monetary turmoil and ambitious development plans. Saudi Arabia faces similar challenges as the leading economy in the Middle East and North Africa region.The objective of this study is to pinpoint the macroeconomic determinants influencing Saudi Arabia’s current account balance from 1995 to 2019. This aligns with the objectives of Saudi Vision 2030, which emphasizes economic diversification and sustainability.Eleven macroeconomic determinants were subjected to the Principal Component Analysis model and the Autoregressive Distributed Lag model for analysis. Five determinants, such as budget balance, goods exports, per capita gross domestic product, gross domestic product growth, and domestic liquidity growth, were identified as significant contributors to the current account balance. The Autoregressive Distributed Lag model revealed that goods exports, domestic liquidity growth, gross domestic product growth, and per capita gross domestic product exert a statistically significant positive impact on the current account balance in the long term.The research findings highlight the significance of goods exports, economic growth, and domestic liquidity in shaping Saudi Arabia’s current account balance, emphasizing the need for diversification away from oil dependence to mitigate economic vulnerabilities. The study underscores the implications for Saudi Vision 2030, stressing strategic policy interventions to foster non-oil exports and stimulate economic growth. Additionally, the analysis identifies temporal variations in export dynamics, emphasizing the importance of policy continuity and adaptability for economic resilience. AcknowledgmentsThe authors gratefully acknowledge financial support from The Deanship of Scientific Research, King Faisal University (KFU) in Saudi Arabia. The present work was done under Project Number (CHAIR 138).

Inter-annual and seasonal variations of the metazoan parasite communities of the blue sea catfish Ariopsis guatemalensis (Siluriformes: Ariidae), in a tropical coastal lagoon

Parasitological studies of long-term inter-annual variations provide more precise and reliable information about the biological structure of fish parasite communities, and constitute a reference data base for future studies. A total of 1103 blue sea catfish Ariopsis guatemalensis from a tropical eutrophic coastal lagoon were examined for parasites over a 22-year period (from May 2000 to October 2022), to test the hypothesis that parasite communities of this host, should exhibit greater variations in their structure and species composition mainly over long-term periods. Three species of monoxenous (single-host life cycle), and nine of heteroxenous (multi-host life cycle) parasites were identified. The results indicated that parasite species composition of this catfish has remained stable over a 22-years period. However, the community structure has registered notable changes over periods of several years, mainly due to the replacement of the numerically dominant species. Temporal variations in the infection dynamics of component parasite species, were possibly caused by a combination of biotic and abiotic factors, influenced by the seasonal dry/rainy cycle, which can affect the availability of intermediate host populations, as well as the feeding and reproductive behavior of the host.

Late Glacial-Holocene cirque glacier chronology on sub-Antarctic Kerguelen Archipelago (49°S) based on cosmogenic 36Cl exposure dating

Sub-Antarctic glacier chronologies can provide valuable information about the past variability of climate dynamics in the Southern Ocean region. The Kerguelen Archipelago (49°S) is advantageously located under the influence of the Southern Hemisphere's westerly wind belt, thus fluctuations of climate-sensitive glaciers on Kerguelen can provide a baseline for understanding the behavior of this atmospheric regime in response to climatic forcings. We present 17 36Cl exposure ages of moraine and erratic boulders to provide chronological constraints to paleoglacier extents of the Guynemer cirque glacier, located just north of the Cook Ice Cap. Erratic boulders show ice thinning in the Guynemer region started to occur in the Late Glacial by 13.5 ka and continued past 12.4 ka. Ice retreat was punctuated by the formation of two moraine stages, the outermost at 11.5 ± 0.4 ka followed by another at 10.4 ± 1.2 ka, which are indicative of Early Holocene glacier advances/standstills. A glacial advance occurred at 1.4 ± 0.3 ka, which corroborates other Late Holocene re-advances elsewhere on the archipelago. Finally, three undated moraine stages are found between 1.4 ka and the 1960s. The lack of moraines after 10.4 ka and through the Mid-Holocene suggests that the Guynemer glacier was significantly smaller during this extended period of the Holocene compared to its Early Holocene as well as its Late Holocene limits. The Guynemer glacier history provides unique evidence of Early Holocene moraines on Kerguelen, which have not been discovered thus far on the archipelago. Similar to glaciers in Patagonia, New Zealand and South Georgia, the Guynemer glacier was at its largest Holocene extent in the Early Holocene. However, while other southern mid-latitude glacier chronologies show progressively smaller glacial extents throughout the Mid- to Late Holocene, the Late Holocene re-advance of the Guynemer glacier, like other Kerguelen glaciers, likely exceeded its Mid-Holocene extent.

Dynamics and scale variations of blooms of Phaeocystis globosa “giant colony” ecotype and key environmental factors in the Beibu Gulf, China

The Beibu Gulf has experienced blooms of Phaeocystis globosa “giant colony” ecotype (PGGCE), with noticeable variations in bloom scale across years. However, driving environmental factors and their roles remain poorly understood. In this study, we quantified dynamics of PGGCE cells in 2016–2017 and 2018–2019, and analyzed their correlations with environment factors. The results revealed that PGGCE blooms primarily occurred in Guangxi coast and western waters of Leizhou Peninsula during winter months, exhibiting distinct developmental processes. Bloom intensity, duration, and distribution differed significantly between two bloom events. In 2016–2017, peak PGGCE density exceeded 2.0 × 105 cells L−1 nearly double that of 2018–2019. Furthermore, bloom sustained five months during 2016–2017, compared to three months during 2018–2019. Prolonged period of low temperatures and elevated nitrate concentrations favored PGGCE growth and colony formation, resulting in a larger scale bloom during winter 2016 as opposed to winter 2018.

Comprehensive Analysis of Flow Dynamics and Pressure Variations in PEM Water Electrolyzers: Experimental and Computational Insights into Gas Diffusion Electrodes

Polymer Electrolyte Membrane Water Electrolyzers (PEMWEs) can produce green hydrogen with zero emission with renewable energy sources integration. The gas diffusion electrodes (GDEs) are one of the main components of PEMWE. In this study, the flow behavior of GDEs for different patterns like square GDE (SGDE), circle GDE (CGDE), equilateral triangle GDE (ETGDE), and rhombic GDE (RGDE) was investigated numerically and experimentally for different flow rates at 100 mL min−1, 200 mL min−1, and 300 mL min−1. In pressure drop (ΔP) and flow visualization experiments, SGDE showed the best performance. Experimental results were compared with each other by validating them in the numerical analysis of multiphase flow conditions. As a result, at 100 mL min−1 flow rate, the flow is directed to the outlet side with 38.96 % less pressure loss in SGDE geometry. In flow visualization experiments, at 100 mL min−1 flow rate, SGDE geometry fills the cell faster than other GDE geometries by 0.437 sec. The results from the ex-situ ink test performance of the GDEs were confirmed in electrochemical single cell PEMWE tests via Pt coated GDEs. Furthermore, SGDE exhibited superior performance in thein-situtests. In the numerical calculation results, when 16 % porosity filter paper was examined, it was concluded that the SGDE geometry was 94.8 % rate successfully carried the liquid phase to all geometry. It is supposed that water transfer inside the cell may be improved by using an SGDE for the anode GDE, and the performance of PEMWE could be increased by providing faster delivery of the oxygen gas and excess water to the outside of the cell.

High-throughput 16S rRNA gene-based amplicon sequencing reveals the functional divergence of halophilic bacterial communities in the Suaeda salsa root compartments on the eastern coast of China

The rhizosphere environment of plants, which harbors halophilic bacterial communities, faces significant challenges in coping with environmental stressors, particularly saline soil properties. This study utilizes a high-throughput 16S rRNA gene-based amplicon sequencing to investigate the variations in bacterial community dynamics in rhizosphere soil (RH), root surface soil (RS), root endophytic bacteria (PE) compartments of Suaeda salsa roots, and adjoining soils (CK) across six locations along the eastern coast of China: Nantong (NT), Yancheng (YC), Dalian (DL), Tianjin (TJ), Dongying (DY), and Qingdao (QD), all characterized by chloride-type saline soil. Variations in the physicochemical properties of the RH compartment were also evaluated. The results revealed significant changes in pH, electrical conductivity, total salt content, and ion concentrations in RH samples from different locations. Notably, the NT location exhibited the highest alkalinity and nitrogen availability. The pH variations were linked to HCO3− accumulation in S. salsa roots, while salinity stress influenced soil pH through H+ discharge. Despite salinity stress, enzymatic activities such as catalase and urease were higher in soils from various locations. The diversity and richness of bacterial communities were higher in specific locations, with Proteobacteria dominating PE samples from the DL location. Additionally, Vibrio and Marinobacter were prevalent in RH samples. Significant correlations were found between soil pH, salinity, nutrient content, and the abundance and diversity of bacterial taxa in RH samples. Bioinformatics analysis revealed the prevalence of halophilic bacteria, such as Bacillus, Halomonas, and Streptomyces, with diverse metabolic functions, including amino acid and carbohydrate metabolisms. Essential genes, such as auxin response factor (ARF) and GTPase-encoding genes, were abundant in RH samples, suggesting adaptive strategies for harsh environments. Likewise, proline/betaine transport protein genes were enriched, indicating potential bioremediation mechanisms against high salt stress. These findings provide insight into the metabolic adaptations facilitating resilience in saline ecosystems and contribute to understanding the complex interplay between soil conditions, bacterial communities, and plant adaptation.

Остров Колгуев как объект мониторинга биоты западного сектора российской Арк­тики

The article presents the research results on the Kolguev Island Arctic biota dynamics under climate change in the 21st century. The researchers substantiate the prospects for using the island as a model territory for studying the dynamics of the biota in the western sector of the Russian Arctic. They outline that the area meets all the requirements for a monitoring object due to the relative representativeness of climate, vegetation and landscapes, spatial integrity, diversity of biota, variability of structure, functioning and dynamics, as well as the presence of long-term observation series. The researchers propose a system of indicators for monitoring the state of the biota, soils and ecosystems of the island and methods of their observation.

Invasive-plant traits, native-plant traits, and their divergences as invasion factors.

Invasive plants exert significant ecological impacts on native plants, communities, and ecosystems. However, consistent conclusions regarding how traits of invasive plants, native plants, and their divergences affect invasion dynamics are still lacking. Here, we conducted a pairwise common garden experiment to investigate how invasion was influenced not only by invasive plants but also by native plants, aiming to elucidate the role of invasive-plant traits, native-plant traits, and their divergences in invasion processes. Our findings revealed variations in invasive stage depending on the combinations of invasive and native plants. Specifically, native plants such as A. argyi, A. lavandulifolia, and C. album exhibited competitive superiority when co-occurring with the three invasive plants. S. viridis, A. vestita, and A. annua had competitive superiority when they co-occurred with E. canadensis, G. quadriradiata, and E. annuus respectively. Furthermore, our results demonstrated that the competitive abilities of invasive plants were primarily influenced by factors such as height, diameter, and biomass allocation, while native plants' competitive abilities were mainly affected by diameter, biomass allocation, and function group differences. Moreover, our analysis revealed that invasive-plant traits, native-plant traits, their divergences, and their interactions together explained 36.88% of the variation in invasion dynamics, with invasive-plant traits and the native-plant traits explaining 10.19% and 6.88%, respectively. In conclusion, the traits of invasive and native plants, along with their divergences, significantly influence interspecific relationships, and influencing the invasive stages. Divergences in competitive strategies between the native plants and invasive plants facilitated invasion processes. Our study not only contributes to understanding the mechanisms underlying invasion, but also provides a scientific foundation for predicting and managing the negative effects of invasive plants.

Inundation dynamics in seasonally dry floodplain forests in southeastern Brazil

AbstractFloodplains are one of the most threatened ecosystems. Even though the vegetation composition in floodplain forests is expected to reflect the variation in groundwater levels and flood duration and frequency, there is little field data on the inundation dynamics (e.g., the variability in flood duration and flood frequency), especially for the understudied seasonally dry tropics. This limits our understanding of these ecosystems and the mechanisms that cause the flooding. We, therefore, investigated six floodplain forests in the state of Minas Gerais in Brazil for 1.5 years (two wet seasons): Capivari, Jacaré, and Aiuruoca in the Rio Grande basin, and Jequitaí, Verde Grande, and Carinhanha in the São Francisco basin. These locations span a range of climates (humid subtropical to seasonal tropical) and biomes (Atlantic forest to Caatinga). At each location, we continuously measured water levels in five geomorphologically distinct eco‐units: marginal levee, lower terrace, higher terrace, lower plain, and higher plain, providing a unique hydrological dataset for these understudied regions. The levees and terraces were flooded for longer periods than the plains. Inundation of the terraces lasted around 40 days per year. The levees in the Rio Grande basin were flooded for shorter durations. In the São Francisco basin, the flooding of the levees lasted longer and the water level regime of the levees was more similar to that of the terraces. In the Rio Grande basin, flooding was most likely caused by rising groundwater levels (i.e., “flow pulse”) and flood pulses that caused overbank flooding. In the São Francisco basin, inundation was most likely caused by overbank flooding (i.e., “flood pulse”). These findings highlight the large variation in inundation dynamics across floodplain forests and are relevant to predict the impacts of changes in the flood regime due to climate change and other anthropogenic changes on floodplain forest functioning.

P‐181: Enhancing the Bragg‐Reflection by Blending Ag Nanoparticles in Polymer Stabilized Cholesteric Liquid Crystals

The coupling between the incident light and the highly reflective nanoparticles is believed to potentially raise the reflective intensity of PSCLCs by creating a channel that causes the incident light to reach the helical CLCs and reflect outward. Therefore, in this research Ag nanoparticles were blended into polymer stabilized cholesteric liquid crystals (PSCLCs) to enhance their reflective intensity. A small amount of blending Ag nanoparticles (less than 1.0 wt%) in PSCLCs that investigated with 1wt% ‐ 3wt% RM 257 polymerization effectively leads to an increase of the reflective intensity of up to 17%, but has little effect on their thermally induced dynamical reflection variations. These results indicate that the blending of Ag nanoparticles in PSCLCs is an adequate method for the investigation of highly reflective PSCLCs.

Infection dynamics of subtype H9N2 low pathogenic avian influenza a virus in turkeys

While mammals can be infected by influenza A virus either sporadically or with well adapted lineages, aquatic birds are the natural reservoir of the pathogen. So far most of the knowledge on influenza virus dynamics was however gained on mammalian models. In this study, we infected turkeys using a low pathogenic avian influenza virus and determined the infection dynamics with a target-cell limited model. Results showed that turkeys had a different set of infection characteristics, compared with humans and ponies. The viral clearance rates were similar between turkeys and ponies but higher than that in humans. The cell death rates and cell to cell transmission rates were similar between turkeys and humans but higher than those in ponies. Overall, this study indicated the variations of within-host dynamics of influenza infection in avian, humans, and other mammalian systems.

A novel thin plate spline methodology to model tissue surfaces and quantify tumor cell invasion in organ-on-chip models

Organ-on-chip (OOC) models can be useful tools for cancer drug discovery. Advances in OOC technology have led to the development of more complex assays, yet analysis of these systems does not always account for these advancements, resulting in technical challenges. A challenging task in the analysis of these two-channel microfluidic models is to define the boundary between the channels so objects moving within and between channels can be quantified. We propose a novel imaging-based application of a thin plate spline method – a generalized cubic spline that can be used to model coordinate transformations – to model a tissue boundary and define compartments for quantification of invaded objects, representing the early steps in cancer metastasis. To evaluate its performance, we applied our analytical approach to an adapted OOC developed by Emulate, Inc., utilizing a two-channel system with endothelial cells in the bottom channel and colorectal cancer (CRC) patient-derived organoids (PDOs) in the top channel. Initial application and visualization of this method revealed boundary variations due to microscope stage tilt and ridge and valley-like contours in the endothelial tissue surface. The method was functionalized into a reproducible analytical process and web tool – the Chip Invasion and Contour Analysis (ChICA) – to model the endothelial surface and quantify invading tumor cells across multiple chips. To illustrate applicability of the analytical method, we applied the tool to CRC organoid-chips seeded with two different endothelial cell types and measured distinct variations in endothelial surfaces and tumor cell invasion dynamics. Since ChICA utilizes only positional data output from imaging software, the method is applicable to and agnostic of the imaging tool and image analysis system used. The novel thin plate spline method developed in ChICA can account for variation introduced in OOC manufacturing or during the experimental workflow, can quickly and accurately measure tumor cell invasion, and can be used to explore biological mechanisms in drug discovery.

The observed evolution of sub‐daily to multi‐day heavy precipitation in Switzerland

AbstractHeavy precipitation is a major natural hazard in the Alps. Understanding the possible changes due to climate change is a prerequisite for effective climate adaptation and protection. In this study, we revisit the long‐term (1901–2023) evolution of daily and multi‐day heavy precipitation intensity and frequency, discuss trends for sub‐daily to multi‐day events in the recent period 1981–2023 and investigate elevation dependencies in the complex topography of Switzerland. We analyze station measurements from MeteoSwiss' dense operational network covering the whole country and a wide range of elevation levels. We find that daily maximum precipitation and the frequency of precipitation events exceeding the 99th all‐day percentile have increased since 1901 with a peak in the 1980s and decreases thereafter. For the recent period 1981–2023, positive trends in summer heavy precipitation intensity are detected for short (10‐min to 3‐h) events, but no changes are found for the frequency of these moderate extreme events. For longer (1‐ to 5‐day) events on the other hand, decreases in intensity and frequency are found, especially for the winter half‐year. We hypothesize that the opposing trends on the centennial (1901–2023) vs. decadal (1981–2023) time scales are caused by the interaction between thermodynamics, reflecting the primary influence of human‐induced climate change, and the internal variability of atmospheric dynamics. Moreover, we observe a small negative elevation dependency of the daily long‐term trends up to 2300 m above sea level. For the 1981–2023 trends, no strong elevation dependencies are found for sub‐daily events. For daily events, we find small opposing negative summer and positive winter elevation dependencies for both intensities and frequencies. The reason for these tendencies remains unclear. Our results underscore the need to further investigate the interplay between climate change, internal variability of large‐scale dynamics and elevation to better understand heavy precipitation variability in the complex Alpine terrain.

Geographic variation in reproductive traits and germination-niche dynamics in conservation-dependent Banksia arborea populations restricted to banded ironstone formations

The temperature and moisture requirements for reproduction (i.e. seed production and germination) underpin the biogeographical relationships between climate, distribution and population dynamics of plants, particularly narrow range endemic species. We aimed to investigate reproductive outputs and the responses of seeds to temperature and moisture availability across three Banksia arborea populations that are distributed over a narrow range (< 200 km2) of semi-arid habitat on banded ironstone formations of Western Australia. We conducted reproductive trait assessments by quantifying follicles per cone, proportion of viable seed and associated seed mass followed by hydrothermal germination assessments for each population to characterise temperature and water stress tolerance. We found the southern-most population, that receives marginally higher rainfall, had heavier seeds (10 ± 0.02 mg), a cooler optimum temperature (16.1 °C) and wider germination capacity under water stress at 10 °C and 15 °C (Ψb50 = -0.66 to -0.87 MPa) compared to the two northern populations (Ψb50 = -0.60 to -0.65 MPa). By contrast, both northern populations had slightly warmer optimum temperatures for germination (16.9–17.5 °C) and a higher capacity to germinate under water stress at warmer temperatures of 22.5 °C (Ψb50 = -0.43 to -0.56 MPa, compared to -0.29 MPa). Our work highlights that, even within the specific requirements of a narrow range endemic, different populations adapt to marginally different temperature and water stress tolerances. Warming of the southern populations could impact on future recruitment, and conservation action to promote resilient ecosystems are suggested.

Seasonal variation of limnological parameters and phytoplankton dynamics in the high-altitude oligotrophic lakes of Tawang district, Arunachal Pradesh (India)

Seasonal variation of limnological parameters and phytoplankton dynamics in the high-altitude oligotrophic lakes of Tawang district, Arunachal Pradesh (India)

Piezoelectric Actuators in Smart Engineering Structures Using Robust Control.

In this study, piezoelectric patches are used as actuators to dampen structural oscillations. Damping oscillations is a significant engineering challenge, and the use of piezoelectric patches in smart structures allows for a reduction in oscillations through sophisticated control methods. This analysis involved H-infinity (H∞) robust analysis. H∞ (H-infinity) control formulation is a robust control design method used to ensure system stability and performance under disturbances. When applied to piezoelectric actuators in smart structures, H∞ control aims to design controllers that are robust to variations in system dynamics, external disturbances, and modeling uncertainties, while meeting specified performance criteria. This study outlines the piezoelectric effects and advanced control strategies. A structural model was created using finite elements, and a smart structural model was analyzed. Subsequently, dynamic loads were applied and oscillation damping was successfully achieved by employing advanced control techniques.

How to quantify developmental synchrony in malaria parasites

Malaria infections represent an iconic example of developmental synchrony, where periodic fevers can result when the population of parasites develops synchronously within host red blood cells. The level of synchrony appears to vary across individual hosts and across parasite species and strains, variation that—once quantified—can illuminate the ecological and evolutionary drivers of synchrony. Yet current approaches for quantifying synchrony in parasites are either biased by population dynamics or unsuitable when population growth rates vary through time, features ubiquitous to parasite populations in vitro and in vivo. Here we develop an approach to estimate synchrony that accounts for population dynamics, including changing population growth rates, and validate it with simulated time series data encompassing a range of synchrony levels in two different host-parasite systems: malaria infections of mice and human malaria parasites in vitro. This new method accurately quantifies developmental synchrony from per capita growth rates using obtainable abundance data even with realistic sampling noise, without the need to sort parasites into developmental stages. Our approach enables variability in developmental schedules to be disentangled from even extreme variation in population dynamics, providing a comparative metric of developmental synchrony.