Regular Pattern Research Articles

Numerical and experimental assessment of tilted-helical fiber orientation effects on deformation of pneumatic soft actuators

Pneumatic actuation of fiber-reinforced soft-material slender structures, and specifically inflatable cylinders, plays a key role in soft robotics, particularly for generating sought deformations in terms of, e.g. elongation, expansion, torsion, and bending. Fiber-reinforced tubes were widely investigated, in particular by considering regular helical patterns for the fibers, and multiple sets of fibers were introduced for achieving relatively richer deformations such as coiling (i.e. combined bending and torsion). However, coiling can be obtained even by introducing a single tilted-helical fiber, thus potentially simplifying actuator design and implementation. Therefore, in this study, we numerically investigated the effect of fiber orientation on the coiling behavior of tilted-helical fiber-reinforced cylindrical actuators. Specifically, we used finite element numerical simulations to determine the effect of fiber pitch and tilt angle on the curvature and twist angle of an inflated cylindrical actuator, and we assessed numerical results based on corresponding experiments. Finally, we addressed a preliminary design chart based on the inverse map linking coiling to the corresponding pitch and tilt angle. Our results take an initial step for the design of tilted-helical fiber-reinforced actuators, with potential application to a wider class of inflatable soft actuators to program a desired coiled configuration through the integration of a single tilted-helical fiber.

Self-enhanced mobility enables vortex pattern formation in living matter.

Ranging from subcellular organelle biogenesis to embryo development, the formation of self-organized structures is a hallmark of living systems. Whereas the emergence of ordered spatial patterns in biology is often driven by intricate chemical signalling that coordinates cellular behaviour and differentiation1-4, purely physical interactions can drive the formation of regular biological patterns such as crystalline vortex arrays in suspensions of spermatozoa5 and bacteria6. Here we discovered a new route to self-organized pattern formation driven by physical interactions, which creates large-scale regular spatial structures with multiscale ordering. Specifically we found that dense bacterial living matter spontaneously developed a lattice of mesoscale, fast-spinning vortices; these vortices each consisted of around 104-105 motile bacterial cells and were arranged in space at greater than centimetre scale and with apparent hexagonal order, whereas individual cells in the vortices moved in coordinated directions with strong polar and vortical order. Single-cell tracking and numerical simulations suggest that the phenomenon is enabled by self-enhanced mobility in the system-that is, the speed of individual cells increasing with cell-generated collective stresses at a given cell density. Stress-induced mobility enhancement and fluidization is prevalent in dense living matter at various scales of length7-9. Our findings demonstrate that self-enhanced mobility offers a simple physical mechanism for pattern formation in living systems and, more generally, in other active matter systems10 near the boundary of fluid- and solid-like behaviours11-17.

Keloid and Hypertrophic Scars Treatment.

Hypertrophic scars are contained within the site of injury and may regress over time, while keloids spread beyond the borders of the initial injury and do not regress. On histologic examination, hypertrophic scars tend to have collagen in a wavy, regular pattern, whereas keloids have no distinct pattern of collagen. To retrospectively analyze improvement in keloid and hypertrophic scars characteristics following treatment with Ablative 10600nm and a non-Ablative 1570nm Hybrid Laser Device. Treatment parameters with the ProScan Hybrid Mode were 40W/1.3-1.5ms for the CO2 and 12W/4ms for the 1570nm in a 1:1 ratio. Outcomes were assessed based on physician scar grading as measured by the Vancouver Scar Scale and patient-reported satisfaction. Excel was used for data analysis, and a p value < 0.05 was considered statistically significant. Adverse events and patient pain were also recorded. A total of 31 hypertrophic scars and 30 keloid scars were treated. There was a significant reduction in Vancouver Scar Scale scores for both hypertrophic and keloid scars (62% ± 8% and 58% ± 7%; p = 2.6E-17 and p = 8.29E-26, respectively). In a scar-based comparison, a statistically significant difference was observed for all measures reflecting favorable outcomes for hypertrophic scars (VSS, p = 1.1E-05; satisfaction, p = 0.0112; pain, p = 0.00081). Only one adverse event was reported, a superficial burn treated with topical antibiotics. The device was found to be safe and effective, with promising results for the treatment of hypertrophic and keloid scars. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Flow stirred by open turbine: A modal analysis of multiscale flow characteristics

AbstractThe turbulence observed in the stirred tank is a result of the superposition of flows at different scales, each exerting various influences on the operational processes. To understand the flow characteristics associated with stirring, this paper undertakes particle image velocimetry (PIV) experimental research on an unbaffled tank stirred by an open turbine featuring four distinct blade deflection angles. The flow field in the unbaffled tank manifests as a double‐circulation flow pattern; however, it is worth noting that the blade deflection angle exerts a significant impact on the stirring process. Specifically, when the blade deflection angle reached 90°, the flow discharge aligned closely with the radial direction, accompanied by pronounced fluctuations in the high‐velocity region. The Lagrangian coherent structures (LCS) formed were subsequently extracted and subjected to finite‐time Lyapunov exponent (FTLE) analysis. Notably, a more regular wake pattern emerged in proximity to the blade tip, while a larger scale flow structure persisted along the flow direction. To systematically analyze the flow field stirred by the open turbine, modal analysis was employed. By reconstructing the flow field based on the principle of 50% energy content, the decomposition of flows at different scales was achieved. The turbulent kinetic energy (TKE) generated by the various scale flows was subsequently calculated, revealing that the high TKE values primarily originate from the large‐scale flow structure. Conversely, the TKE generated by the small‐scale flow exhibits a uniform distribution across different regions. Notably, in regions characterized by higher velocities, the peak TKE associated with the small‐scale flow also manifests; however, it is significantly smaller in magnitude compared to that generated by the original flow or the large‐scale flow.

Inductive 3D numerical modelling of the tibia bone using MRI to examine von Mises stress and overall deformation

Abstract As the main load bearer throughout the gait cycle, the tibia is a crucial bone in the lower leg that distributes ground reaction forces with each stride. Comprehending the distribution of stress inside the tibia is essential for both avoiding fractures and developing efficient methods of redistributing load to promote healing and biomechanical correction. The study examined the stress, strain, and deformation encountered by the tibia over a 7-s walking cycle using an ANSYS workbench software, using tibia bone under a period of force applied to the boundary condition at intervals of 0.2 s. The tibia encounters stress levels varying from 0 to 1,400 N, exhibiting a regular pattern that aligns with the loading attributes often associated with traditional walking. The research conducted in this study identified the occurrence of maximum stress levels, measuring 25.45 MPa. Additionally, related peak elastic strains and deformations were observed, measuring 2.19 × 10−3 and 2.43 mm, respectively. The patterns that have been seen indicate that there is an initial contact of the foot with the ground, followed by the bearing of weight and subsequently the toe-off. These observed patterns closely resemble the natural motion of the foot during the act of walking. Temporal fluctuations in elastic strain through the tibia throughout a gait cycle reveal that the strain is mostly cantered at the medial surface of the tibia. Additional investigation into the elastic properties and overall deformations of the tibia yielded valuable observations on prospective areas of interest within the bone’s structure. These findings are of utmost importance for biomechanical assessments and the identification of potential injury hazards in subsequent research endeavours.

Experimental study of flame extension lengths and fire pattern lengths induced by the turbulent jet fire impinging on inclined wooden boards

The safety of producing and transporting flammable gas may be compromised by the occurrence of jet fires resulting from pipeline leakage. During such incidents, combustible obstacles can impede the development of vertical jet fires, leading to impingement. Wood, a typical building material, was chosen as a combustible solid for the experiment due to its ability to produce regular fire patterns on its surface when heated, making it useful for fire investigation. A series of experiments were conducted to examine the flame extension length and fire pattern length resulting from a jet fire impinging on inclined wooden boards with different nozzle diameters, inclination angles, and heat release rates. This work showed that, unlike non-combustible boards, the rate of increase in flame extension length beneath a wooden board continues to rise as the heat release rate increases. Additionally, the boards' ability to absorb heat during the initial stages of combustion affects the flame extension length at low heat release rates. This work introduces a new correlation that can predict the length of flame extension under wooden boards, addressing a gap in research on jet fire impingement on combustible ceilings. For the regular fire patterns left by jet fires impinging on wooden boards, a new correlation of fire pattern length with flame extension length for different inclination angles of wooden boards is proposed. Considering the characteristics of turbulence, a novel model for fire pattern length is introduced, incorporating the Karlovitz flame stretch factor, nozzle inner diameter, and fire source-wooden board spacing.

Expect the unexpected: a new species of killifish from a highly stochastic temporary wetland near Iguazú Falls (Cyprinodontiformes: Rivulidae)

We describe Argolebias adrianae, a new species of killifish from a small temporary wetland in the Paraná Forest ecoregion with no regular or predictable temporal pattern of water availability. This habitat is in the Lower Iguazú River Basin, known for its high fish endemism, but until now, only two species of Rivulidae were reported from it, but from the Araucarian Forest ecoregion. The genus Argolebias was previously only known from the lower portions of the Paraguay, Paraná, and Uruguay basins and middle Paraná. The new species is distinguished from all congeners by its unique coloration, which includes a conspicuously dark grey anterior third portion of the dorsal fin and the absence of iridescent spots on the basal half of the pectoral fin in live adult males, as well as dark grey spots on the anterocentral portion of the flanks of females. Our phylogenetic analysis shows A. adrianae to be closely related to Argolebias guarani from the adjacent Middle Paraná basin. We also provide data on the ecology, ontogeny of coloration, and chorion ornamentation of this species. Our findings have important implications for understanding the biogeography, ecology, and evolution of mechanisms that enable organisms to thrive in highly stochastic environments like this one.

Waveform characteristics in thoracic paravertebral space: a prospective observational study

Background With increased use of thoracic paravertebral block (TPVB) in thoracic surgery, many faced the challenge of locating the thoracic paravertebral space (TPVS) ultrasonographically. This observational study aimed to investigate the waveform characteristics and pressure value within the TPVS in anaesthetized patients with controlled ventilation. Methods 50 patients scheduled for elective lung surgery were enrolled. After conduction of anesthesia, all patients underwent TPVB at T4/5 and T6/7 using transverse, in-plane ultrasound guidance. A pressure transducer system with a desktop monitor was connected to the needle hub to measure pressure values and waveform characteristics in three locations: the paraspinal muscles, immediately behind the superior costotransverse ligament, and within the TPVS. Next, 15 mL of 0.33% bupivacaine was injected into each desired TPVS. After completion of the surgery, the extent of dermatomal blockade and the pain score was assessed in all patients. Results 98 typical regular respiratory waveforms with a mean pressure of ≤ 25 mmHg were detected in the TPVS of 50 patients. The sensitivity of the combined ultrasound and pressure waveform measurement technique to identify the TPVS was 95.45% (95% confidence interval, 84.527–99.445). Nontypical respiratory waveforms were present in two patients. Factors interfering with the TPVS waveform characteristics were previous thoracic surgery and chronic pleural inflammation. Conclusion The TPVS had low pressure and showed a smooth, regular waveform pattern corresponding to respiration.

Owens Valley Radio Observatory monitoring of LS I +61°303 completes three cycles of the super-orbital modulation

Context. The high-mass X-ray binary LS I +61°303 is composed of a Be-type star and a compact object in an eccentric orbit. The emission from this source is variable and periodic across the electromagnetic spectrum, from radio to very high-energy γ rays. The orbital period has been determined as P1 ≈ 26.5 d, and the source also features a super-orbital period with a value of Plong ≈ 4.6 years. Long-term monitoring of the binary by the Owens Valley Radio Observatory (OVRO) at 15 GHz has now completed 13.8 years, which corresponds to three full cycles of the super-orbital period. This is exactly one long-term cycle more than in the previous publication about OVRO observations of this source. Aims. Our aim is to investigate the presence and the stability of periodic signals in the radio data and to test if they are in agreement with previous results. This will contribute to the understanding of the physical processes behind the non-thermal emission from this source. Methods. We performed a timing analysis of the OVRO radio light curve and made use of the generalized Lomb-Scargle periodogram. We also combined the OVRO data with the full archive of previous radio observations and computed the discrete autocorrelation function. Results. The most powerful features in the periodogram of the OVRO data are two peaks at P1 = 26.49 ± 0.05 d and P2 = 26.93 ± 0.05 d, which are well separated from each other and clearly stand out above the very low noise level. The previously detected long-term period is still present in these new radio data, and our measurement is Plong = 1698 ± 196 d. Dividing the OVRO data into three segments of equal length showed that the two periods, P1 and P2, are present in the periodogram of each of the consecutive long-term cycles. Our analysis of the full radio archive resulted in the detection of the same three periods, and the autocorrelation function showed a regular pattern, proving the continuity of the decades-spanning stability of the super-orbital modulation. In addition, we report a possible systematic modulation of the radio flux density with a timescale of approximately 40 years that has so far remained unnoticed. Conclusions. The physical model of a relativistic jet whose mass loading is modulated with the orbital period P1 and is precessing with the slightly larger period P2, giving rise to a beating with period Plong, had previously been able to reproduce the radio and gigaelectron volt emission from this source. The ongoing presence and the stability of the periodic signals imply that this model is still the most plausible explanation for the physical processes at work in this source.

Exploring transformer fault detection using RFID technology

Real-time monitoring and fault diagnosis of transformers are essential for the stable power system operation. This paper presents an RFID-based transformer fault feature extraction and classification algorithm. Experiments show that monitored current signals are stable while the temperature peak is 356°C. Hilbert decomposition reveals regular current and voltage patterns that can be used as fault indicators. Signal strength classification accuracy reached 80% . At rated load, the transformer temperature soared to 186°C, indicating overheating issues. The monitoring during a sample day showed that overload events were concentrated from 16:00-20:00, which required attention. The approach helps accurately identify transformer fault types from real-time RFID data for proactive maintenance. Compared to reactive repairs after failures, this not only improves employee productivity but also reduces costs. Based on customized RFID deployment, the algorithm contributes to the stability and economy of power infrastructure.

Unveiling the Shadows: The Alarming Link Between Sleep Irregularity and Dementia

Nature has beautifully planned nocturnal hours during which neurobiological processes critical for the preservation of cognitive health and prevention of dementia take place. Irregular sleeping may interfere with the brain’s function of eliminating neurotoxic, and results in onset of neurodegeneration. Studies have revealed a surprising relationship between irregular sleeping and dementia. &#x0D; Dementia is known to be major cause of disability and mortality worldwide. According to WHO, estimated 55 million individual suffering with dementia globally and this number is expected to raise up to 140 million in 2050 [1]. A variety of neurodegenerative diseases comes under dementia, and they are all characterized by a loss of cognitive abilities including memory, language, problem-solving, and the capacity to carry out daily tasks. Alzheimer disease is the most common form and may contribute to 60–70% of all cases. It is due to accumulation of beta-amyloid. &#x0D; Irregular sleeping has become a widespread problem that is silently draining millions of people's cognitive capacities and may even be the precursor to dementia. Findings have shown U-shaped relationship between sleep regularity and dementia risk. Very irregular and overly consistent sleep patterns, both are linked to a higher risk of dementia. &#x0D; Previous studies have shown the association between irregular sleeping and dementia but does not prove that dementia is caused by irregular sleep. Future studies, including longer follow-up periods and inquiries into the underlying molecular mechanisms, are required to better understand the complicated link between sleep regularity and dementia. It would be helpful to conduct further intervention trials aimed at improving irregular sleep in individuals with highly variable sleep patterns in order to ascertain whether restoring regular sleep patterns actually enhances brain health. &#x0D; Currently, there is no treatment available for any of the prevalent form of dementia, including frontotemporal dementia, Alzheimer's disease, vascular dementia, and Lewy body dementia. Individual with dementia can preserve the quality of life and well-being by engaging in physical activity and by maintaining the social connections that stimulate brain functioning. Some tips can be followed to improve sleep, such as maintaining a regular sleep schedule or abstaining from caffeine and stimulating screen time 1-2 hours before bed or by consulting your doctor for assistance and to discuss your sleep issues, habits, and general health. &#x0D; In summary, the connection between sleep disorders and dementia serves as a warning, drawing attention to a frequently overlooked aspect that may be essential to prevent a wave of subsequent cognitive deterioration.

Pace setting as an adaptive precursor of rhythmic musicality.

Human musicality (the capacity to make and appreciate music) is difficult to explain in evolutionary terms, though many theories attempt to do so. This paper focuses on musicality's potential adaptive precursors, particularly as related to rhythm. It suggests that pace setting for walking and running long distances over extended time periods (endurance locomotion, EL) is a good candidate for an adaptive building block of rhythmic musicality. The argument is as follows: (1) over time, our hominin lineage developed a host of adaptations for efficient EL; (2) the ability to set and maintain a regular pace was a crucial adaptation in the service of EL, providing proximate rewards for successful execution; (3) maintaining a pace in EL occasioned hearing, feeling, and attending to regular rhythmic patterns; (4) these rhythmic patterns, as well as proximate rewards for maintaining them, became disassociated from locomotion and entrained in new proto-musical contexts. Support for the model and possibilities for generating predictions to test it are discussed.

Reconstruction of multi-phase parametric maps in 4D-magnetic resonance fingerprinting (4D-MRF) by optimization of local T1 and T2 sensitivities.

Time-resolved magnetic resonance fingerprinting (MRF), or 4D-MRF, has been demonstrated its feasibility in motion management in radiotherapy (RT). However, the prohibitive long acquisition time is one of challenges of the clinical implementation of 4D-MRF. The shortening of acquisition time causes data insufficiency in each respiratory phase, leading to poor accuracies and consistencies of the predicted tissues' properties of each phase. To develop a technique for the reconstruction of multi-phase parametric maps in four-dimensional magnetic resonance fingerprinting (4D-MRF) through the optimization of local T1 and T2 sensitivities. The proposed technique employed an iterative optimization to tailor the data arrangement of each phase by manipulation of inter-phase frames, such that the T1 and T2 sensitivities, which were quantified by the modified Minkowski distance, of the truncated signal evolution curve was maximized. The multi-phase signal evolution curves were modified by sliding window reconstruction and inter-phase frame sharing (SWIFS). Motion correction (MC) and dot product matching were sequentially performed on the modified signal evolution and dictionary to reconstruct the multi-parametric maps. The proposed technique was evaluated by numerical simulations using the extended cardiac-torso (XCAT) phantom with regular and irregular breathing patterns, and by in vivo MRF data of three health volunteers and six liver cancer patients acquired at a 3.0 T scanner. In simulation study, the proposed SWIFS approach achieved the overall mean absolute percentage error (MAPE) of 8.62%±1.59% and 16.2%±3.88% for the eight-phases T1 and T2 maps, respectively, in the sagittal view with irregular breathing patterns. In contrast, the overall MAPE of T1 and T2 maps generated by the conventional approach with multiple MRF repetitions were 22.1%±11.0% and 30.8%±14.9%, respectively. For in-vivo study, the predicted mean T1 and T2 of liver by the proposed SWIFS approach were 795ms±38.9ms and 58.3ms±11.7ms, respectively. Both simulation and in vivo results showed that the approach empowered by T1 and T2 sensitivities optimization and sliding window under the shortened acquisition of MRF had superior performance in the estimation of multi-phase T1 and T2 maps as compared to the conventional approach with oversampling of MRF data.

Spatial-temporal order-disorder transition in angiogenic NOTCH signaling controls cell fate specification.

Angiogenesis is a morphogenic process resulting in the formation of new blood vessels from pre-existing ones, usually in hypoxic micro-environments. The initial steps of angiogenesis depend on robust differentiation of oligopotent endothelial cells into the Tip and Stalk phenotypic cell fates, controlled by NOTCH-dependent cell-cell communication. The dynamics of spatial patterning of this cell fate specification are only partially understood. Here, by combining a controlled experimental angiogenesis model with mathematical and computational analyses, we find that the regular spatial Tip-Stalk cell patterning can undergo an order-disorder transition at a relatively high input level of a pro-angiogenic factor VEGF. The resulting differentiation is robust but temporally unstable for most cells, with only a subset of presumptive Tip cells leading sprout extensions. We further find that sprouts form in a manner maximizing their mutual distance, consistent with a Turing-like model that may depend on local enrichment and depletion of fibronectin. Together, our data suggest that NOTCH signaling mediates a robust way of cell differentiation enabling but not instructing subsequent steps in angiogenic morphogenesis, which may require additional cues and self-organization mechanisms. This analysis can assist in further understanding of cell plasticity underlying angiogenesis and other complex morphogenic processes.

Immortalised murine R349P desmin knock-in myotubes exhibit a reduced proton leak and decreased ADP/ATP translocase levels in purified mitochondria

Desmin gene mutations cause myopathies and cardiomyopathies. Our previously characterised R349P desminopathy mice, which carry the ortholog of the common human desmin mutation R350P, showed marked alterations in mitochondrial morphology and function in muscle tissue. By isolating skeletal muscle myoblasts from offspring of R349P desminopathy and p53 knock-out mice, we established an immortalised cellular disease model. Heterozygous and homozygous R349P desmin knock-in and wild-type myoblasts could be well differentiated into multinucleated spontaneously contracting myotubes. The desminopathy myoblasts showed the characteristic disruption of the desmin cytoskeleton and desmin protein aggregation, and the desminopathy myotubes showed the characteristic myofibrillar irregularities. Long-term electrical pulse stimulation promoted myotube differentiation and markedly increased their spontaneous contraction rate. In both heterozygous and homozygous R349P desminopathy myotubes, this treatment restored a regular myofibrillar cross-striation pattern as seen in wild-type myotubes. High-resolution respirometry of mitochondria purified from myotubes by density gradient ultracentrifugation revealed normal oxidative phosphorylation capacity, but a significantly reduced proton leak in mitochondria from the homozygous R349P desmin knock-in cells. Consistent with a reduced proton flux across the inner mitochondrial membrane, our quantitative proteomic analysis of the purified mitochondria revealed significantly reduced levels of ADP/ATP translocases in the homozygous R349P desmin knock-in genotype. As this alteration was also detected in the soleus muscle of R349P desminopathy mice, which, in contrast to the mitochondria purified from cultured cells, showed a variety of other dysregulated mitochondrial proteins, we consider this finding to be an early step in the pathogenesis of secondary mitochondriopathy in desminopathy.

Collaboration and Competition: A Social Network Analysis of Thailand’s Music Industry

This study quantitatively investigates the collaborative framework and competitive landscape of Thailand’s evolving music industry, driven by technological progress and changing consumer preferences. By examining data obtained from Thailand’s Department of Intellectual Property, specifically 138,868 songs, it explores the complex network of relationships among music creators, artists, and various rights-holders, including those associated with recording, music, melodies, and lyrics. Utilizing social network analysis, this research uncovers a power law distribution in these networks, reflecting a scale-free market configuration. This characteristic is marked by a few dominant players exercising considerable market influence, contrasted with numerous less-interconnected participants. This investigation notes regular patterns of collaboration between artists and different rights-holders. Furthermore, the network of music creators displays small-world properties, with short collaborative distances fostering efficient information exchange and creative synergy. Crucially, this study identifies key influential players instrumental in directing the industry’s major trends, highlighting their role in market concentration. These significant findings will provide critical evidence for informing future policy development aimed at improving efficiency and equity in the digital content industries.

A hybrid bio-inspired sandwich structures for high strain rate energy absorption applications

Due to its advantages in terms of enhancing the performance of structures in the desired applications, the bio-inspired design approach has recently attracted the interest of researchers in a number of engineering disciplines. A hybrid bio-inspired design is suggested for the sandwich structures to absorb the energy of the blast loads in the current study. The sandwich structure's core, which often has a regular grid pattern resembling a honeycomb structure, is crucial to how well the panel absorbs energy. In order to achieve the best results, we first chose the structure of the core grid by taking into account potential 2D grids (polygons and multi-pointed stars) through Genetic Algorithm optimization. Next, we combined a bio-inspired bi-tubular thin-walled structure with the core grid to take advantage of its high energy absorption capacity. Finally, the performance of the suggested design is compared with four frequently implemented ones. The results show that the hybrid design has better energy absorption characteristics compared with the bionic and conventional designs presented in the literature.

Diazotrophic community in the sediments of Poyang Lake in response to water level fluctuations.

Water level fluctuations (WLFs) are typical characteristic of floodplain lakes and dominant forces regulating the structure and function of lacustrine ecosystems. The sediment diazotrophs play important roles in contributing bioavailable nitrogen to the aquatic environment. However, the relationship between the diazotrophic community and WLFs in floodplain lakes is unknown. In this paper, we carried out a comprehensive investigation on the alpha diversity, abundance, composition and co-occurrence network of the sediment diazotrophs during different water level phases in Poyang Lake. There were no regular variation patterns in the alpha diversity and abundance of the sediment diazotrophs with the water level phase transitions. The relative abundance of some diazotrophic phyla (including Alphaproteobacteria, Deltaproteobacteri, Euryarchaeota, and Firmicutes) and genera (including Geobacter, Deferrisoma, Desulfuromonas, Rivicola, Paraburkholderia, Methylophilus, Methanothrix, Methanobacterium, and Clostridium) was found to change with the water level phase transitions. The results of ANOSIM, PerMANOVA, and DCA at the OTU level showed that the diazotrophic community structure in the low water level phase was significantly different from that in the two high water level phases, while there was no significant difference between the two high water level phases. These results indicated that the diazotrophic community was affected by the declining water level in terms of the composition, while the rising water level contributed to the recoveries of the diazotrophic community. The diazotrophs co-occurrence network was disrupted by the declining water level, but it was strengthened by the rising water level. Moreover, redundancy analysis showed that the variation of the diazotrophic community composition was mostly related to sediment total nitrogen (TN) and total phosphorous (TP). Interestingly, the levels of sediment TN and TP were also found to vary with the water level phase transitions. Therefore, it might be speculated that the WLFs may influence the sediment TN and TP, and in turn influence the diazotrophic community composition. These data can contribute to broadening our understanding of the ecological impacts of WLFs and the nitrogen fixation process in floodplain lakes.

Effect of Boundaries on Pattern Formation in a Monolayer of Interacting Dipoles

AbstractSelf‐organization can be defined as a process of arrangement of entities that start out in an irregular arrangement and evolve into a stable, regular pattern without the aid of an external agent. A system of magnetic particles that are constrained to move only in a plane is reported. The individual components in the system have dipole moments in an orientation perpendicular to the plane of motion and the interaction between components is purely repulsive. For such a system, it is attempted to understand the influence of the boundary of the monolayer on the patterns that emerge. A system with a small number of magnets is found where the range of the magnetic interactions is of the size of the boundary; the symmetry of the boundary imposed on the monolayer plays a crucial role in determining the pattern types, the number of different pattern types, and the frequency of appearance of a particular pattern type. The effect of scaling up the size of the system while maintaining the characteristics of individual components as well as the component areal density is also discussed.

A Mahalanobis Distance-Based Approach for Dynamic Multiobjective Optimization With Stochastic Changes

In recent years, researchers have made significant progress in handling dynamic multi-objective optimization problems (DMOPs), particularly for environmental changes with predictable characteristics. However, little attention has been paid to DMOPs with stochastic changes. It may be difficult for existing dynamic multi-objective evolutionary algorithms (DMOEAs) to effectively handle this kind of DMOPs because most DMOEAs assume that environmental changes follow regular patterns and consecutive environments are similar. This paper presents a Mahalanobis Distance-based approach (MDA) to deal with DMOPs with stochastic changes. Specifically, we make an all-sided assessment of search environments via Mahalanobis distance on saved information to learn the relationship between the new environment and historical ones. Afterward, a change response strategy applies the learning to the new environment to accelerate the convergence and maintain the diversity of the population. Besides, the change degree is considered for all decision variables to alleviate the impact of stochastic changes on the evolving population. MDA has been tested on stochastic DMOPs with 2 to 4 objectives. The results show that MDA performs significantly better than the other latest algorithms in this paper, suggesting that MDA is effective for DMOPs with stochastic changes.