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Experimental and theoretical studies have highlighted the impact of gene flow on the probability of evolutionary rescue in structured habitats. Mathematical modeling and simulations of evolutionary rescue in spatially or otherwise structured populations showed that intermediate migration rates can often maximize the probability of rescue in gradually or abruptly deteriorating habitats. These theoretical results corroborate the positive effect of gene flow on evolutionary rescue that has been identified in experimental yeast populations. The observations that gene flow can facilitate adaptation are in seeming conflict with traditional population genetics results that show that gene flow usually hampers (local) adaptation. Identifying conditions for when gene flow facilitates survival chances of populations rather than reducing them remains a key unresolved theoretical question. We here present a simple analytically tractable model for evolutionary rescue in a two-deme model with gene flow. Our main result is a simple condition for when migration facilitates evolutionary rescue, as opposed as no migration. We further investigate the roles of asymmetries in gene flow and/or carrying capacities, and the effects of density regulation and local growth rates on evolutionary rescue.

Bias correction methods are used to compensate for any tendency to overestimate or underestimate the downscaled variables. Rainfall, maximum, and minimum temperatures are the key climate variables where the socioeconomic activities of the regions are principally based on rain-fed agriculture. This paper compares the performance of regional climate models (RCMs) and bias correction methods in Gelana and Deme watersheds in Ethiopia during the base period of 1988–2019. Observed data obtained from the Ethiopian National Meteorological Agency were used for performance evaluation of the RCM outputs. The performance of the three selected RCMs and four bias correction methods were evaluated by using four statistical indicators: Pearson correlation coefficient (R), root mean square error, Nash–Sutcliffe efficiency, and percent bias. The results show that the RACMO22T and HIRHAM5 models performed better than the RCA4 model in reproducing daily precipitation, and maximum and minimum temperatures in the Deme and Gelana watersheds. Similarly, the empirical quantile mapping method for precipitation and maximum temperature bias correction, and the distribution mapping method for minimum temperature bias correction, were well performed and preferable to adjust the climate variables of the future periods in these watersheds. Moreover, all RCMs performed better in the Deme watershed than in the Gelana watershed.

One of the most effective corrective control strategies to prevent voltage collapse and instability is load shedding. In this paper, a multiple-deme parallel genetic algorithm is used for a suitable design of load shedding. The load shedding algorithm is implemented when the voltage stability margin index of the power system is lower than a predefined value. In order to increase the computational speed, the voltage stability margin index is estimated by a modular neural network method in a fraction of a second. In addition, in order to use the exact values of the voltage stability margin index for neural network training, a simultaneous equilibrium tracing technique has been employed considering the detailed model of the components of the generating units such as the governor and the excitation system. In the proposed algorithm, the entire population is partitioned into several isolated subpopulations (demes) in which demes distributed in different processors and individuals may migrate occasionally from one subpopulation to another. The proposed technique has been tested on New England-39 bus test system, and the obtained results indicate the efficiency of the proposed method.

High herbivore abundances on trees surrounded by distantly related neighbors (phylogenetic isolation) might in part be due to local adaptation of herbivores to host trees, but this has not been tested. We studied if free‐feeding and semi‐concealed (shelter‐building) Lepidoptera can be adapted to leaf traits of individual trees, and if this is affected by phylogenetic isolation. We performed a reciprocal transplant experiment on free‐feeding and semi‐concealed lepidopteran caterpillars collected from oak trees (Quercus petraea) in a mixed forest in Poland. Within a set of trees with early and a set with late budburst, we selected oak trees that varied from being surrounded by other oak trees (low phylogenetic isolation) to oaks surrounded by pine trees (high phylogenetic isolation), and collected canopy branches to obtain caterpillars. We then fed half of the caterpillars leaves from the tree they were collected from (home tree) and others on the leaves of another tree in the set (away trees) in the laboratory. We measured caterpillar mass over a five‐day interval to calculate growth rate and determined aspects of leaf chemistry of each tree. Five species of Lepidoptera (Acrobasis repandana, Eudemis profundana, Operopthera brumata, Phycita roborella, Zeiraphera isertana) yielded sufficient sample sizes for statistical analyses. Overall, we found faster growth on home trees, which could be attributed to one species, E. profundana. There was no effect of phylogenetic isolation. Our results indicate that local adaptation to leaf traits of individual trees is rare in these lepidopterans, and we found no evidence that local adaptation would be more pronounced on trees that are more phylogenetically isolated from their neighbors. Therefore, the effects phylogenetic isolation on herbivory are not likely to be mediated by local adaptation to individual trees. We performed a reciprocal transplant experiment in which we reared half of the caterpillars collected from large oak trees in a forest on leaves from the home tree, and the rest on leaves of the other oak trees. We found that in one species, the growth rate was higher on leaves of the home tree, indicating adaptation to the individual trees.

In view of their unique shape morphing behaviour, dielectric elastomer-based minimum energy structures (DEMES) have received an increasing attention in the technology of electroactive soft transduction. Because several of them undergo a time-dependent motion during their operation, understanding their nonlinear dynamic behaviour is crucial to their effective design. Additionally, in the recent past, there has been a growing scientific interest in imparting anisotropy to the material behaviour of dielectric elastomers in view of ameliorating their actuation performance. Spurred with these ongoing efforts, this paper presents an analytical framework for investigating the nonlinear dynamic behaviour of aniso-visco-hyperelastic DEMES actuator with an elementary rectangular geometry. We use a rheological model comprising two Maxwell elements connected in parallel with two single spring elements for modelling the material behaviour of the DE membrane. The governing equations of motion for the underlying non-conservative system are then derived using the Euler–Lagrange equation. The proposed model is used for building insights into the attainable equilibrium states, periodicity of the response as well as the resonant behaviour of the DEMES actuator over a feasible range of anisotropy and viscosity parameters. Our results reveal that the DEMES with hyperelastic material properties exhibits a supercritical pitchfork bifurcation of equilibrium state which is further accelerated in terms of attained equilibrium angle due to membrane anisotropy. A significant enhancement in the equilibrium angle attained by the structure with the extent of membrane anisotropy parameter is observed, indicating a favourable impact of material anisotropy. Poincare maps and phase-portraits are presented for assessing the periodicity of the nonlinear oscillations. The frequency response of the actuator for a combined DC and AC load indicates an upsurge in the resonant frequency with an increase in anisotropy parameter. The underlying analytical model and the trends presented in this study can find their potential use in the design and development of the futuristic anisotropic DEMES actuators subjected to time-dependent actuation.

Climate change is believed to have led to changes in global patterns. This study evaluated the hydrological responses to climate change in the Deme watershed using the Soil and Water Assessment Tool (SWAT) for two consecutive periods of 2031–2050 and 2051–2070. Climate variables were downscaled from RACMO22T, under RCP4.5 and RCP8.5 scenarios from CORDEX-Africa. Distribution mapping and variance scaling methods were used for bias correction of precipitation and temperatures, respectively, and for further analysis. The SWAT model was calibrated (and validated) for the 1989–2000 (2001–2010) period, and the hydrological model showed a reasonably good agreement. The result shows that the rainfall and streamflow show a decreasing signal in the wet season. The maximum projected change in annual temperature, PET, and ET was 2.15 °C, 10.89, and 9.24%, respectively, in the far future period under the RCP8.5 scenario. These incremental changes have an impact on declining annual rainfall and streamflow up to 27.6 and 26.2%, respectively, under the RCP8.5 scenario in 2031–2050. The subsequent results were the maximum decline of surface runoff by 15.10%, groundwater by 14.78%, and total water yield by 26.10% in 2031–2050 under the RCP8.5 scenario. Thus, the concerned body integrates its duties with climate change.

Carangidae fish feature streamlined, oval, or rhomboid bodies with flat and high sides, making them adept at swimming swiftly through water with minimal resistance. Dielectric elastomers (DEs), known for their high strain, rapid response times, and high electromechanical coupling efficiency under an electric field, are intelligent materials suitable for creating various actuators widely employed in flexible bionic robots. By utilizing smart material-driven soft fins, bionic robot fish can more realistically simulate the movements of actual fish, improving their swimming performance. In this study, we employed a DE-based actuator to develop a bionic robot fish resembling Carangidae, driven by fins. Leveraging the minimum energy structure of DE material, we designed a structure inspired by the Carangidae family to replicate the fin swing of the bionic robot fish. We investigated the swimming behavior of this bionic robot fish under sinusoidal voltage signals of varying amplitudes and frequencies. The bionic robot fish swims in the medium and/or paired fin (MPF) propulsion mode, achieving a maximum speed of 8.6 mm/s. This work presents a novel scheme and theoretical foundation for the application of dielectric elastomers in bionic Carangidae robots.

Dielectric Elastomer Minimum Energy Structures (DEMES) have the ability of actively adjusting their shape to accommodate complex scenarios, understanding the actuation mechanism of DEMES is essential for their effective design and control, which has rendered them a focus of research in the field of soft robotics. The actuation ability of DEMES is usually influenced by external conditions, among which the electromechanical properties of DE materials are highly sensitive to temperature changes, and the pre-stretch ratio of DE materials has a significant impact on the dynamic performance of DEMES. Therefore, it is necessary to study the effects of temperature and pre-stretch ratio on the nonlinear dynamic behavior of DEMES. In this paper, in response to the lack of research on the influence of DE pre-stretch ratio on the actuation characteristics of DEMES, this paper proposes a systematic modeling and analysis framework that comprehensively considers pre-stretch factors, temperature factors, and viscoelastic factors, and establishes the motion control equation of DEMES affected by the coupling effect of DE pre-stretch ratio and temperature. The proposed analytical framework is used to analyze the evolution of the electromechanical response of DEMES under voltage excitation under the coupling of DE pre-stretch ratio and temperature. The results indicate that the bending angle, inelastic deformation, resonant frequency, and dynamic stability of DEMES can be jointly adjusted by the DE pre-stretch ratio and ambient temperature. A low pre-stretch ratio of DE can lead to dynamic instability of DEMES, while appropriate temperature conditions and higher pre-stretch ratios can significantly improve the actuation ability of DEMES. This can provide theoretical guidance for the design and deformation control of DEMES.

Micro- and macrovascular consequences of atherosclerosis, arterial hypertension, dyslipidemia, and smoking can affect neurotransmission and markers for neuronal activity. The potential direction and specifics are under study. It is also known that optimal control of hypertension, diabetes, and dyslipidemia in midlife may positively affect cognitive functioning later in life. However, the role of hemodynamically significant carotid stenoses in neuronal activity markers and cognitive functioning is still being debated. With the increased use of interventional treatment for extracranial carotid disease, the question of whether it might affect neuronal activity indicators and whether we can stop or even reverse the path of cognitive deterioration in patients with hemodynamically severe carotid stenoses naturally emerges. The existing state of knowledge provides us with ambiguous answers. We sought the literature for possible markers of neuronal activity that can explain any potential difference in cognitive outcomes and guide us in the assessment of patients throughout carotid stenting. The combination of biochemical markers for neuronal activity with neuropsychological assessment and neuroimaging may be important from practical point of view and may provide the answer to the question for the consequences of carotid stenting for long-term cognitive prognosis.

Propagation of chaos is a well-studied phenomenon and shows that weakly interacting diffusions may become independent as the system size converges to infinity. Most of the literature focuses on the case of exchangeable systems where all involved diffusions have the same distribution and are “of the same size”. In this paper, we analyze the case where only a few diffusions start outside of an accessible trap. Our main result shows that in this “sparse regime” the system of weakly interacting diffusions converges in distribution to a forest of excursions from the trap. In particular, initial independence propagates in the limit and results in a forest of independent trees.