Search

• Integrated and multi-functional energy storage devices with excellent mechanical properties are fabricated. • The integrated paper-based supercapacitor displays ultrahigh areal specific capacitance. • The integrated paper-based supercapacitor shows excellent sensing and humidity power generation characteristics. • Zn2+ conductivity and transport mechanism are investigated by molecular dynamics simulation. The demand for flexible electric heating devices has increased due to technology advancement and improved living standards. These devices have various applications including personal thermal management, hyperthermia, defrosting, agricultural heating film, and oil-water separation. Joule heat, generated by electric currents, is commonly used in electrical appliances. To incorporate Joule heating into flexible electronics, new materials with excellent mechanical properties are necessary. Traditional polymers, used as reinforcements, limit the continuity of conductive networks in composites. Therefore, there is a need to develop flexible Joule thermal composite materials with enhanced mechanical strength and conductivity. Cellulose, a widely available renewable resource, is attracting attention for its excellent mechanical properties. It can be used as a dispersant and reinforcing agent for conductive fillers in cellulose-based composites, creating highly conductive networks. Various forms of cellulose, such as wood, nanocellulose, pulp fiber, bacterial cellulose, cellulose paper, textile clothing, and aramid fiber, have been utilized to achieve high-performance Joule thermal composites. Researchers have achieved excellent mechanical properties and developed efficient electric heating devices by designing cellulose-based composites with different structures. The scalable production methods enable large-scale application of cellulose-based devices, each with unique advantages in 1D, 2D, and 3D structures. This review summarizes recent advancements in cellulose-based Joule thermal composites, providing insights into different structural devices, and discussing prospects and challenges in the field. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, we have proposed and analyzed a predator–prey system introducing the cost of predation fear into the prey reproduction with Holling type-II functional response in the stochastic environment with the consideration of non-linear harvesting on predators. The system experiences Transcritical, Saddle–node, Hopf, and Bogdanov-Taken (BT) bifurcation with respect to the intrinsic growth rate and competition rate of the prey populations. We have discussed the existence and uniqueness of positive global solution of the stochastic model with the help of Ito's integral formula and the long-term behavior of the solution is derived here. The existence of stationary distribution and explicit form of the density function is established here when only prey populations survive or both populations. We have shown that due to high fluctuation, the regime changes from one stable state to another state when bistability occurs in the system. The paper ends with some conclusions. [ABSTRACT FROM AUTHOR]

Quasi-Monte Carlo (QMC) methods have been gaining popularity in computational finance as they are competitive alternatives to Monte Carlo methods that can accelerate numerical accuracy. This paper develops a new approach for reducing the effective dimension combined with a randomized QMC method. A distinctive feature of the proposed approach is its sample-based transformation that enables us to choose a flexible manipulation via regression. In the proposed approach, the first step is to perform a regression using the samples to estimate the parameters of the regression model. An optimal transformation is proposed based on the regression result to minimize the effective dimension. An advantage of this approach is that adopting a statistical approach allows greater flexibility in selecting the regression model. In addition to a linear model, this paper proposes a dimension reduction method based on a linear-quadratic model for regression. In numerical experiments, we focus on pricing different types of exotic options to test the effectiveness of the proposed approach. The numerical results show that different regression models are chosen depending on the underlying risk process and the type of derivative securities. In particular, we show several examples where the proposed method works while existing dimension reductions are ineffective. • We propose a sample-based transformation algorithm based on a regression. • The proposed scheme approximates the payoff of a financial option as a linear-quadratic function. • It can reduce the estimator's variance with a randomized QMC via dimension reduction. • The proposed scheme is particularly effective in pricing complex options. • We also show the effectiveness of ridge regression in the scheme. [ABSTRACT FROM AUTHOR]

This paper proposes finite-difference schemes based on triangular stencils to approximate partial derivatives using bivariate Lagrange polynomials. We use first-order partial derivative approximations on triangles to introduce a novel hexagonal scheme for the second-order partial derivative on any rotated parallelogram grid. Numerical analysis of the local truncation errors shows that first-order partial derivative approximations depend strongly on the triangle vertices getting at least a first-order method. On the other hand, we prove that the proposed hexagonal scheme is always second-order accurate. Simulations performed at different triangular configurations reveal that numerical errors agree with our theoretical results. Results demonstrate that the proposed method is second-order accurate for the Poisson and Helmholtz equation. Furthermore, this paper shows that the hexagonal scheme with equilateral triangles results in a fourth-order accurate method to the Laplace equation. Finally, we study two-dimensional elliptic differential equations on different triangular grids and domains. [ABSTRACT FROM AUTHOR]

This paper analyzes a discrete-time Cournot competition model with time delays taking into consideration the dynamics of market interactions involving one public firm and multiple private firms. The model assumes that the production output of the public firm is influenced by the past output levels of the private firms. The output levels of the private firms are affected by the past production outputs of both the public firm and their private competitors. The study identifies two equilibrium states within the nonlinear system: a positive equilibrium and a boundary equilibrium. Through a stability analysis, it is established that the boundary equilibrium is a saddle point. In the absence of time delays, the stability region for the positive equilibrium is determined. The research explores various specific delay scenarios, finding conditions under which the positive equilibrium is asymptotic stability. Additionally, the occurrence of flip and Neimark–Sacker bifurcations are examined. In order to illustrate the complex dynamics, the paper provides a series of numerical examples. • We explore Cournot competition with delays, involving both public and private firms. • Two equilibria are found: positive and boundary, with boundary as a saddle point. • Stability of positive equilibrium is analyzed, with and without time delays. • Flip/Neimark–Sacker bifurcations are investigated supported by numerical examples. [ABSTRACT FROM AUTHOR]

The impact of air pollutants on the human respiratory system has received more and more attention. However, due to the differences in human characteristics and the strength of protective measures, different people have different symptoms in air pollution and viral infection environments. In this paper, an S I 1 I 2 P dynamic model of respiratory diseases infected by virus under air pollution is established by introducing air pollutant concentration compartment. Qualitative research shows that there are seven equilibria in the system, the daily average emission and clearance rate of pollutants are the key parameters affecting the existence and stability of equilibria. In this paper, by using Sotomayor's theorem and center manifold theory, it is proved that the system undergoes saddle–node bifurcation or Bogdanov–Takens bifurcation of co-dimension 3 at the boundary equilibrium, and exhibits saddle–node bifurcation at the endemic equilibrium. Numerical simulation results show that wearing masks in haze weather can not only reduce the number of allergic patients, but also reduce the number of viral patients. In addition, reducing the daily average emission of air pollution and increasing its clearance rate can also reduce the number of allergic patients. It is worth mentioning that this measure is more effective in controlling viral respiratory diseases. • The heterogeneity of patients is taken into consideration. • The average daily emission of air pollution, the clearance rate and the proportion of illness are the key parameters affecting the existence, local asymptotic stability and bifurcation. • Respiratory diseases can be controlled by reducing the daily average emission of air pollution and its clearance rate, and this measure has a better control effect on viral respiratory diseases. [ABSTRACT FROM AUTHOR]

This paper presents a new approach that uses the Reservoir Computing Algorithm to solve Fokker-Planck-Kolmogorov (FPK) equation excited by both Gaussian white noise and non-Gaussian noise. Unlike typical numerical methods, this methodology does not necessitate spatial reconstruction or numerical supplementation. The novelty of this paper lies in the modifications made to the conventional Reservoir Computing algorithm. We altered the approach for calculating values of the input weight matrix and incorporated autoregressive techniques in the reservoir layer. In addition, we applied data normalization to the training data before training the algorithm to avoid a zero solution. The efficacy of this approach was verified through multiple arithmetic examples, showcasing its practicality and efficiency in solving FPK equations. Moreover, the Reservoir Computing-FPK algorithm is capable of solving high-dimensional and fractional-order FPK equations with a smaller training set than earlier algorithms. Finally, we analyzed how values of the input weight matrix and regularization parameter affected the performance of the algorithm. The findings suggest that the careful selection of hyperparameters can greatly improve the performance of the Reservoir Computing algorithm. [ABSTRACT FROM AUTHOR]

This paper presents a novel A-stable nonlinear method of order of accuracy three, based on optimization for solving the first-order initial value problems. The A-stability is proven and the consistency of order three is investigated as well. The convergence of the method is established under certain assumptions. Additionally, a second-order method is derived based on this approach, and a variable step size formulation is implemented using the second and third-order methods to enhance efficiency. Numerical examples provided in the paper demonstrate the validity of the theory and underscore the advantages of the method compared to three other A-stable methods of order three, including an implicit RK method, a Rosenbrock method, and an explicit (nonstandard) method. [ABSTRACT FROM AUTHOR]

Studying the interplay of phytoplankton–zooplankton–fish (PP–ZP–F) in an aquatic system is crucial for better understanding of nutrient cycling, assessing ecosystem health, predicting and mitigating harmful algal blooms, and managing fisheries in the water bodies. In order to investigate the effectiveness of nanoparticles (NPs), fear, and harvesting, this paper focuses on exploring the dynamics of a food chain model among PP–ZP–F species. We consider the fear of fish on zooplankton species (which reduces the reproduction rate of ZPs) with saturated fear cost in the presence of nanoparticles (NPs) and harvesting in fish. The system dynamics are studied from the viewpoint of proving positivity, boundedness, and uniqueness, followed by analysing the existence and local stability of biologically feasible equilibria. Conditions for the global stability of the interior equilibrium point are also found. Furthermore, we established the transversality conditions for the occurrence of Hopf, transcritical, and saddle–node bifurcations. To validate our theoretical results, we made numerous phase portraits, time-series graphs, tables showing the extinction of species, and bifurcation diagrams. It is numerically observed that increasing the contact rate of NPs with PPs makes the system stable from chaos, and further increase of contact rate may lead to extinction. Chaos at a low contact rate can also be managed by increasing the fear level, and the chaotic behaviour at a low fear level can again be controlled by enhancing the harvesting of fish species. Over-exploitation may result in the extinction of fish, whereas fear may promote coexistence, stability, and long-term survival of the species. Increased saturated fear cost can make the system chaotic from stable dynamics. Therefore, the theoretical as well as numerical findings of our paper may be of great interest in estimating the behaviour of aquatic systems biologically and practically. [ABSTRACT FROM AUTHOR]

• It is shown that all the nonlinear PDEs and their Lie symmetries derived in the paper "Exact solutions of nonlinear... " CNSNS, 67 (2019), 253-263 have been derived earlier. • The optimal systems of one-dimensional subalgebras of Lie algebras in the above paper are incorrect. • The exact solutions obtained in the above paper follow from earlier works. This comment is devoted to the paper "Exact solutions of nonlinear diffusion-convection-reaction equation: A Lie symmetry approach" (CNSNS, 67 (2019), 253-263) in which several results are not new because were derived much earlier. Moreover, some results in the paper are incorrect or incomplete. [ABSTRACT FROM AUTHOR]

• NRGO/Co 3 O 4 composite aerogels were prepared by a simple three-step method. • The obtained NRGO/Co 3 O 4 composite aerogels showed a 3D porous network structure. • Microwave absorption capacity was regulated by changing addition amounts of Co 3 O 4. • Maximum absorption bandwidth reached up to 6.32 GHz, covering the entire Ku-band. • Minimum reflection loss of −62.78 dB was achieved at a thin thickness of 2.13 mm. The fabrication of advanced graphene-based microwave absorbing materials with thin thickness, wide bandwidth, strong absorption strength, and low filling ratio remains a huge challenge. In this paper, nitrogen-doped reduced graphene oxide/tricobalt tetraoxide (NRGO/Co 3 O 4) composite aerogels were synthesized by a three-step method of solvothermal reaction, high-temperature calcination, and hydrothermal self-assembly. The results showed that the attained NRGO/Co 3 O 4 composite aerogels had a unique three-dimensional porous network structure, extremely low bulk density, and good compression recovery. Furthermore, the effect of the addition amounts of flower-like Co 3 O 4 on the complex dielectric constant and microwave absorption properties of NRGO/Co 3 O 4 composite aerogels was investigated. When the addition amount of Co 3 O 4 was equal to 15 mg, the prepared binary composite aerogel showed the strongest absorption strength of –62.78 dB and a wide absorption bandwidth of 5.5 GHz at a thin thickness of 2.13 mm and a low filling ratio of 15 wt.%. It was worth noting that the maximum absorption bandwidth could reach 6.32 GHz (11.68–18 GHz, spanning the entire Ku-band) at a thickness of 2.24 mm. In addition, the possible microwave absorption mechanism of NRGO/Co 3 O 4 composite aerogels was also proposed. Therefore, this paper will provide a new and simple strategy for preparing RGO-based porous nanocomposites as lightweight, efficient, and broadband microwave absorbers. [Display omitted] [ABSTRACT FROM AUTHOR]

The fixed point theory is one of the most essential techniques of applicable mathematics for solving many realistic problems to get a unique solution by using the well known Banach contraction principle. It has paved the ways for numerous extensions, generalization and development of the theory of fixed points in very diverse settings. Our intention in the present paper is to study the Kannan contraction maps defined on a controlled metric space. The generalization of the fixed point theorem for Kannan contraction on controlled metric space is investigated in this paper. We construct an iterated function system called Controlled Kannan Iterated Function System (CK-IFS) with Kannan contraction maps in a controlled metric space and use it to develop a new kind of invariant set, which is called a Controlled Kannan Attractor or Controlled Kannan Fractal (CK-Fractal). Subsequently, the collage theorem for controlled Kannan fractal is also proved. The multivalued fractals are also constructed in the controlled metric space using Kannan and Reich-type contraction maps. The newly developing iterated function system and fractal set in the controlled metric space can provide a novel direction in the fractal theory. [ABSTRACT FROM AUTHOR]

• The effect of varying WO 3 dimensions on the hydrogen-generating capacity of metal sulfide. • The metal sulfide as photocatalyst for hydrogen evolution has been studied systematically. • Selection of catalyst combinations with different morphologies. In the field of photocatalytic hydrogen production, metal sulfides are frequently utilized, particularly Cd sulfides, which have the benefits of a narrow band gap and a sufficient band gap. Other photocatalysts are required to enhance the situation because it still has a high photogenic carrier recombination rate and has flaws like photocorrosion that need to be fixed. The best morphology combination must be chosen since, as we are all aware, the morphology of the catalyst can significantly alter its activity. To choose the best morphology, we chose maple leaf CdS and WO 3 with various morphologies to construct the S-Scheme heterojunctions, and WO 3 was then applied to other metal sulfides. It is concluded that granular WO 3 –0D and CdS-F have the highest hydrogen evolution activity, which may indicate that 0D has the highest loading capacity and may play a certain supporting role for the catalyst that is easy to agglomerate, exposing more hydrogen evolution active sites to enhance hydrogen production. At the same time, the main hydrogen evolution active crystal face of the metal sulfide in the paper is (1 0 0) crystal face. When the crystal face is exposed, the metal sulfide in the paper has good hydrogen evolution activity, and the hydrogen evolution activity will be greatly reduced after the crystal face is covered. The established spatial angle between the (1 0 0) crystal face exposed by CdS-F and the (1 1 1) crystal face exposed by WO 3 –0D is large, so the highly active crystal face and active site are preserved as much as possible. On the other hand, WO 3 decreases the recombination rate of electron-hole pairs in metal sulfide, resulting in a greater contribution of photogenerated electrons to the hydrogen evolution reaction. The Tafel clearly demonstrates the variation of hydrogen production rate control steps. This offers some suggestions for choosing the photocatalyst's morphological configuration. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper proposes a new method for determining the simulation parameters of the Jiles–Atherton Model used to simulate the first magnetisation curve and hysteresis loop in ferromagnetic materials. The Jiles–Atherton Model is an important tool in engineering applications due to its relatively simple differential formulation. However, determining the simulation parameters for the anhysteretic curve is challenging. Several methods have been proposed, primarily based on mathematical aspects of the anhysteretic and first magnetisation curves and hysteresis loops. This paper focuses on finding the magnetic moments of the material, which are used to define the simulation parameters for its anhysteretic curve. The proposed method involves using the susceptibility of the material and a linear approximation of a paramagnet to find the magnetic moments. The simulation parameters can then be found based on the magnetic moments. The method is validated theoretically and experimentally and offers a more physical approach to finding simulation parameters for the anhysteretic curve and a simplified way of determining the magnetic moments of the material. [ABSTRACT FROM AUTHOR]

This paper aims to obtain less conservative stability and stabilization conditions for sampled-data linear systems with multiple sampling rates. To this end, three novel delay-dependent states resulting from sampling are introduced in the augmented state, enabling the exploitation of the sawtooth-type characteristics of the sampling-induced delay in both stability and stabilization processes. Additionally, a novel discontinuous function is included in Lyapunov–Krasovskii-based functional to enhance the capacity to extract more information from specific sampling pattern for each state. Especially, to strengthen the interdependence among the components of the augmented state, supplementary zero equalities are incorporated into the stability analysis conditions. Furthermore, by including a novel weighted state derivative in the augmented state, this paper proposes an effective method that can transform the parameter-dependent stability conditions into stabilization conditions formulated in terms of linear matrix inequalities. Finally, the validity and practicality of the proposed method are demonstrated through two illustrative examples. [ABSTRACT FROM AUTHOR]

This paper discusses the process of optimizing the shape of systems that are controlled by the Stokes flow with threshold leak boundary conditions. In the theoretical part it focuses on studying the stability of solutions to the state problem in relation to a specific set of domains. In order to facilitate computation, the slip term and impermeability condition are regulated. In the computational part, the optimized portion of the boundary is defined using Bézier polynomials, in order to create a finite dimensional optimization problem. The paper also includes numerical examples to demonstrate the computational efficiency of this approach. [ABSTRACT FROM AUTHOR]

This paper proposes a smooth finite element method (S-FEM) for efficient and accurate analysis of motor magnetic fields. The edge-based smooth finite element (ES-FEM) formulations are derived for two-dimensional triangular element meshes suitable for multi-material motor structures, and then a magnetic flux density calculation method appropriate for S-FEM to calculate nonlinear electromagnetic fields is introduced. In the calculation of motor magnetic field, ES-FEM has a proper softening effect on the stiffness matrix of the finite elements, which makes the calculation more accurate and more efficient than FEM. The magnetic flux intensity calculation method introduced in this paper is not only appropriate for ES-FEM to calculate the nonlinear electromagnetic field of motor, but also can improve the calculation accuracy of magnetic flux density. In the calculation of nonlinear magnetic field of motor, ES-FEM can also improve the calculation accuracy of magnetic field analysis compared with FEM. Several numerical examples demonstrate the improving effect of the ES-FEM discussed above on the motor's magnetic field calculation. [ABSTRACT FROM AUTHOR]

In this paper, the elastostatic and elastodynamic problems are analyzed by using the meshless generalized finite integration method (GFIM). The idea of the GFIM is to construct the integration matrix and the arbitrary functions by piecewise polynomial with Kronecker product, which leads to a significant improvement in accuracy and convenience. However, the traditional direct integration in the GFIM is difficult to deal with a large number of arbitrary functions generated in elastic problems. In order to tackle this problem, a special technique is proposed to construct relationships among arbitrary functions in this paper. Also, the Laplace transform method and the Durbin's inversion technique are adopted to deal with the variables of time in the elastodynamic problem. Several numerical examples are presented to demonstrate the accuracy and stability of the GFIM. [ABSTRACT FROM AUTHOR]

The paper focuses on pricing European-style options on multiple underlying assets under the Black–Scholes model represented by a nonstationary partial differential equation. The numerical solution of such equations is challenging in dimensions exceeding three, primarily due to the so-called curse of dimensionality. The main contribution of the paper is the design and analysis of the method based on combining the sparse wavelet-Galerkin method and the Crank–Nicolson scheme with Rannacher time-stepping enhanced by Richardson extrapolation, which helps overcome the curse of dimensionality. The next contribution is constructing a new orthogonal cubic spline wavelet basis on the interval and a sparse tensor product wavelet basis on the unit cube, which is suitable for the proposed method. The resulting method brings the following important advantages. The method is higher-order convergent with respect to both temporal and spatial variables, and the number of basis functions is significantly reduced compared to a full grid. Furthermore, many matrices involved in the computation are identity matrices, which results in a considerable simplification of the algorithm. Moreover, we prove that the condition numbers of discretization matrices are uniformly bounded and do not depend on the dimension, even without preconditioning, which leads to a small number of iterations when solving the resulting linear system. Numerical experiments are presented for several types of European-style options. [ABSTRACT FROM AUTHOR]

This study introduces a novel approach for integrating a compact mechanism into the Marine Predator Algorithm (MPA), subsequently proposing innovative parallel and communication strategies. The synergistic combination of these methodologies substantially augments the global search efficiency and accelerates the convergence rate of the original MPA. The paper culminates in presenting an enhanced version of the Marine Predator Algorithm, termed PCMPA, which leverages compact parallel technology. The performance of PCMPA, alongside a range of comparative algorithms, is rigorously evaluated using the CEC2013 benchmark test functions. These comparative algorithms encompass recent variants of MPA, PSO, DE, and other newly developed algorithms. Evaluation results reveal that PCMPA outperforms its counterparts in a more extensive array of test functions. To corroborate PCMPA's efficacy in real-world scenarios, the algorithm is applied to parameter optimization in Backpropagation neural network (BNN) and targeted engineering optimization challenges. This application demonstrates that PCMPA consistently achieves enhanced performance in practical implementations. • The study presents a novel variant of the Marine Predators Algorithm, dubbed PCMPA. • The paper benchmarks PCMPA against other Marine Predators Algorithm variants and other Algorithms. • The research applies PCMPA to optimize parameters of BNNs and to tackle engineering optimization challenges. [ABSTRACT FROM AUTHOR]

This paper aims to obtain the numerical solution of a one-dimension fourth-order Kuramoto-Sivashinsky (KS) equation, which has application in the context of flame propagation. This study combines the implementation of two new mechanisms quintic Uniform Algebraic Hyperbolic (QUAH) tension B-spline and quintic Uniform Algebraic Trigonometric (QUAT) tension B-spline with a renowned method known as Differential Quadrature Method (DQM). DQM is used to approximate the derivatives. Then, to obtain the weighting coefficients both quintic splines QUAH and QUAT are implemented with DQM and the original boundary value problem was then transformed into an ordinary differential equation. The Runge-Kutta 43 technique was used to solve the resultant ODE. With this approach, the outcomes are precise and close to the exact solution. The differential quadrature technique has a significant advantage over the previous approaches because it prevents the perturbation in order to find the better results for the given nonlinear equations. The accuracy of the suggested method is then illustrated numerically resolving four test problems and calculating the error norms L 2 and L ∞. Calculated results are displayed graphically and in tabular format for quick and simple access. This paper introduces an original work, to the best of the author's knowledge. The obtained solution and graphical observations show that QUAH and QUAT tension B-splines with DQM is a strong and dependable methods for estimating nonlinear problem solutions. Quintic B-splines are higher-order interpolation method compared to lower-degree B-splines, which results in more accurate approximations, and provides smooth and continuous representations of functions. Moreover, DQM when combined with quintic B-splines, can help reduce numerical dispersion, and can be applied to a wide range of problems. • Two new regimes of order six, referred as Uniform Algebraic Trigonometric and Uniform Algebraic Hyperbolic are proposed. • The Kuromoto-Sivashinsky equation (KS) is numerically solved by combining DQM with splines. • Four test problems have been resolved to gauge how well the current approach works. • Error norms and convergence order are calculated to evaluate the precision and efficiency of the approach. • The unconditional stability of the suggested technique has been proved. [ABSTRACT FROM AUTHOR]

• We introduce population flow and its effect on biodiversity in evolutionary dynamics of rock-paper-scissors game. • According to assumptions on population flows, the system can exhibit various survival states including persistent coexistence and multistability of single group survival. • Population flow can change the carrying simplex for evolutions of the system. • The basin structure for multistability may be spirally entangled and discontinuous. • The coexistence state can exhibit oscillatory dynamics according to the magnitude of population flow. Classic frameworks of rock-paper-scissors game have been assumed in a closed community that a density of each group is only affected by internal factors such as competition interplay among groups and reproduction itself. In real systems in ecological and social sciences, however, the survival and a change of a density of a group can be also affected by various external factors. One of common features in real population systems in ecological and social sciences is population flow that is characterized by population inflow and outflow in a group or a society, which has been usually overlooked in previous works on models of rock-paper-scissors game. In this paper, we suggest the rock-paper-scissors system by implementing population flow and investigate its effect on biodiversity. For two scenarios of either balanced or imbalanced population flow, we found that the population flow can strongly affect group diversity by exhibiting rich phenomena. In particular, while the balanced flow can only lead the persistent coexistence of all groups which accompanies a phase transition through supercritical Hopf bifurcation on different carrying simplices, the imbalanced flow strongly facilitates rich dynamics such as alternative stable survival states by exhibiting various group survival states and multistability of sole group survivals by showing not fully covered but spirally entangled basins of initial densities due to local stabilities of associated fixed points. In addition, we found that, the system can exhibit oscillatory dynamics for coexistence by relativistic interplay of population flows which can capture the robustness of the coexistence state. Applying population flow in the rock-paper-scissors system can ultimately change a community paradigm from closed to open one, and our foundation can eventually reveal that population flow can be also a significant factor on a group density which is independent to fundamental interactions among groups. [ABSTRACT FROM AUTHOR]

Abstract: A diverse class of viscous materials, which includes familiar materials such concrete, wood, and Kevlar, exhibit surprising, counterintutive properties under internal moisture content fluctuations. In test after test over the past 50 years, the viscosity of these materials is observed to decrease, often dramatically, during wetting and drying. The key characteristics of the observed viscous softening are: the decrease in viscosity is temporary, and depending on the specimen size can be greatly delayed with respect to the associated change in weight; the decrease in viscosity is absent under steady state flow. Based on recent research on the properties of water and other polar fluids confined by hydrophilic surfaces, we provide a physical explanation and propose a constitutive law. The resulting model accurately captures the interplay between the pore fluid movement and macroscopic constitutive properties in totality. The model is verified against published data for the creep of paper sheets exposed to cyclic moisture conditions. Experimental data of different materials under similar boundary conditions are compared using a new metric, the creep rate factor. The results further reinforce the idea that nanoscale movement of water enhances the internal ‘lubrication’ of the studied materials, interpreted as loosening of the hydrogen bonds. [Copyright &y& Elsevier]

Abstract: The most representative papers of M. V. Keldysh (10.02.1911-24.06.1978) in the field of mechanics and applied mathematics concerned with aircraft construction, shipbuilding and explosion theory are reviewed. Formulations of problems with their substantiation, the methods of solving them, which he used, and the main results obtained are given. [Copyright &y& Elsevier]

Abstract: Recently, Alaca et al. [Alaca et al., Chaos, Solitons & Fractals 2006;29:1073–9] proved some fixed point theorems in intuitionistic fuzzy metric spaces by a strong definition of Cauchy sequence (see [George and Veeramani, Fuzzy Sets Syst 1994;64:395–9] and [Veeramani and Vasuki, Fuzzy Sets Syst 2003;135:409–13]), also the intuitionistic fuzzy metric space has extra conditions (see [Gregori et al., Chaos, Solitons & Fractals, 2006;28:902–5]). In this paper, we consider generalized intuitionistic fuzzy metric spaces i.e., -fuzzy metric spaces and prove the fuzzy version of Banach and Edelstein contraction theorems in these spaces for modified definition of Cauchy sequence. [Copyright &y& Elsevier]

Abstract: In this communication, we will point out an interesting correspondence between a recent paper “On the properties of equidifferent OWA operator” [International Journal of Approximate Reasoning, in press, doi:10.1016/j.ijar.2005.11.003] by Liu, and an earlier result “On obtaining minimal variability OWA operator weights” [Fuzzy Sets and Systems 136 (2003) 203–215] by Fullér and Majlender. [Copyright &y& Elsevier]

Discusses issues related to the contract of physicians in Great Britain. Details on the IT needs of physicians; Information on inefficient electronic data use; Keys to earning based on the contract.

In this corrigendum we correct an error in our paper [T. Caraballo, R. Colucci, J. López-de-la-Cruz and A. Rapaport. A way to model stochastic perturbations in population dynamics models with bounded realizations, Commun Nonlinear Sci Numer Simulat , 77 (2019) 239–257]. We present a correct way to model real noisy perturbations by considering a slightly different stochastic process based, as in the original paper, on the Ornstein-Uhlenbeck process. Namely, we correct the formulae that generates the noisy realizations to ensure the boundedness property to be satisfied with probability one (which turns out not to be true in our original paper even though it was observed in all the simulations). [ABSTRACT FROM AUTHOR]

The article reflects on the medical regulations proposed in a white paper issued by the British government based on recommendations by Chief Medical Officer Sir Liam Donaldson. It predicts that the proposed elimination of the medical majority of the General Medical Council (GMC) will produce adverse effect. The white paper is anticipated to result in a new Medical Act. The overall revalidation costs under the proposal is estimated to double compared to the current £78 million.

Reports on a white paper that lists the proposals for primary care in Great Britain. Inclusion in the white paper of incentives to general practitioners who will make extension on surgery opening hours; British health secretary Patricia Hewitt remarks on their interests in patients; Advantages of the white paper according to Kailash Chand, secretary at West Pennine Local Medical Committee in England.

In a very recently presented paper, Turky and Abdullah [5] proposed a novel multi-population harmony search with external archive (MHSA-ExtArchive) for dynamic optimization problems. In the experimental results, the authors claimed that their approach could outperform several state-of-the-art algorithms. They also showed the superiority of their method by means of numerical experiments on Moving Peaks Benchmark (MPB). Despite the interesting idea of applying multi-population scheme on harmony search and using a new type of external archive for dealing with dynamic problems, we believe that there are two very important shortcomings in the result analysis, which we point out in this short note. The main motivation of the present note is to contribute toward preventing the same mistakes from happening by the other researchers. [ABSTRACT FROM AUTHOR]

Several letters to the editor in response to previous articles, including one on the white paper Our Health, Our Care, Our Say, and "Death Knell for the Personal Doctor," in the February 14, 2006 issue are presented.

The article reports that the white paper Our Health, Our Care, Our Say is, without doubt, the most serious challenge to general practice (GP) since the inception of the National Health Services, as of February 7, 2006. From now on, primary care trusts will view GP and practices as either part of the solution or part of the problem.

Presents views of several medical professionals on care outside hospitals discussed in the British government's white paper. Actions that should be taken by the government regarding the use of non-medics at primary care level according to Peter Mobbs, chairman of British Orthopaedic Directors Society; Other ways to improve choice without moving care outside hospitals stated by Allan Templeton, president of Royal College of Obstetrics and Gynaecology; Reaction of Andrew Mclrvine, general surgeon at Dartford & Gravesham National Health Trust, to the idea.

Reports on the criticism of general practitioner academics on the consultation to be made by the British government regarding the "Your Health, Your Care, Your Say" primary care white paper. Views of Mike Pringle, general practice professor at Nottingham University in England, on the consultation; Flaws of the questionnaire launched online with the consultation.

Provides information on England's consultation paper intended for general practitioners (GPs) in the country. Proposal for GPs and other health professionals to develop personal health plans; Reinforcement of genito-urinary medical services; Increased role of GPs in smoking cessation programs, domestic abuse and teenage and child health care.

Explains the integration of paper-based and electronic medical records in Great Britain. Advantages of computerization; Maximization of the benefits of a computerized surgery.

Reports on the complaints of angry doctors regarding the failure of the British Medical Association (BMA) to send them ballot papers to vote on the medical consultant contract in England in 2003. Reaction of army doctors who were denied the rights to vote; Criticism against the BMA in relation to the construction contract ballot; Remarks from Shehnaz Somjee of the Locum Doctors Association on the issue.

• Correct an error in our paper published in Communications in Nonlinear Science and Numerical Simulation in 2015. • Construct a new Z 2 -equivariant cubic switching system and prove the existence of 15 limit cycles. • An approach is described for calculating the focus values of systems with two switching lines. In this note, we correct an error in our paper published in Communications in Nonlinear Science and Numerical Simulation in 2015 [5], in which the form of a Z 2 -equivariant cubic planar switching system is not correct. In this note, we add one more switching line and use the same equations given in [5] to construct a correct Z 2 -equivariant cubic system. Then, we prove that the new system can exhibit 15 limit cycles and therefore the conclusion given in [5] still holds. [ABSTRACT FROM AUTHOR]

The condition of Theorem 6 in Li et al. (2020) is invalid for a design having general minimum-lower confounding (GMC) property. The purpose of the note is to correct the result and propose the right condition. The correction has no effect on the main text of Li et al. (2020). [ABSTRACT FROM AUTHOR]

In this paper, an inverse design method for auxetic metamaterials is proposed. The conjugate gradient method is employed to minimize the errors of the required parameters of the designed shape. The interior point penalty method is used to convert constrained inverse problems into unconstrained ones. Using the Taylor expansion, the optimizing step size is derived as well. The boundary element method and the representative volume element are used to compute the effective stiffness matrix. Due to the advantages of the boundary element method, we only need the boundary elements and can easily re-mesh the optimized geometry during the inverse search. The validation test demonstrates that using the computed effective stiffness matrix yields nearly identical results to those obtained from direct finite element analysis. Then, using the proposed method, the authors successfully achieved all three design targets, which proved the effectiveness. Furthermore, the choice of penalty factor has been discussed in this paper as well. [ABSTRACT FROM AUTHOR]

In this paper, we consider Constrained Pseudoconvex Nonsmooth Optimization Problems (CPNOPs), which are a class of nonconvex optimization problems. Due to their nonconvexity, classical convex optimization algorithms are unable to solve them, while existing methods, i.e., numerical integration methods, are inadequate in terms of computational performance. In this paper, we propose a novel approach for solving CPNOPs that combines neurodynamic optimization with deep learning. We construct an initial value problem (IVP) involving a system of ordinary differential equations for a CPNOP and use a surrogate model based on a neural network to approximate the IVP. Our approach transforms the CPNOP into a neural network training problem, leveraging the power of deep learning infrastructure to improve computational performance and eliminate the need for traditional optimization solvers. Our experimental results show that our approach is superior to numerical integration methods in terms of both solution quality and computational efficiency. [ABSTRACT FROM AUTHOR]