Impulsive Model Research Articles

Electronic Spectroscopy and Dissociation Dynamics of Vinyl-Substituted Criegee Intermediates: 2-Butenal Oxide and Comparison with Methyl Vinyl Ketone Oxide and Methacrolein Oxide Isomers

The 2-butenal oxide Criegee intermediate [(CH3CH═CH)CHOO], an isomer of the four-carbon unsaturated Criegee intermediates derived from isoprene ozonolysis, is characterized on its first π* ← π electronic transition and by the resultant dissociation dynamics to O (1D) + 2-butenal [(CH3CH═CH)CHO] products. The electronic spectrum of 2-butenal oxide under jet-cooled conditions is observed to be broad and unstructured with peak absorption at 373 nm, spanning to half maxima at 320 and 420 nm, and in good accord with the computed vertical excitation energies and absorption spectra obtained for its lowest energy conformers. The distribution of total kinetic energy released to products is ascertained through velocity map imaging of the O (1D) products. About half of the available energy, deduced from the theoretically computed asymptotic energy, is accommodated as internal excitation of the 2-butenal fragment. A reduced impulsive model is introduced to interpret the photodissociation dynamics, which accounts for the geometric changes between 2-butenal oxide and the 2-butenal fragment, and vibrational activation of associated modes in the 2-butenal product. Application of the reduced impulsive model to the photodissociation of isomeric methyl vinyl ketone oxide reveals greater internal activation of the methyl vinyl ketone product arising from methyl internal rotation and rock, which is distinctly different from the dissociation dynamics of 2-butenal oxide or methacrolein oxide.

Synergy of Investment Projects: A Cognitive Approach

An important part of the analysis of economic growth of regions is the study of the investment distribution within industries and Russian Federation regions. Carefully considered construction of extra value sequences can create positive impulses because of the synergetic effects of investment projects. The purpose of the study is to analyze the synergetic effects of regional investment projects and impulse modeling their effects on Russian economic system. Finding such effects requires complex mathematical models implementation, and usually it cannot describe all existing investment relationships. Cognitive modeling methods can become the solution of stated problem. Cognitive modeling is a combination of mathematical approaches and expert assessments. The following study includes multidimensional factor statistical analysis, which was applied to construct a cognitive map for impulse modeling. Based on investment projects in Russia, there were identified 4 main generalized economic factors. These factors were sets of closely interrelated industries. Complied factors were energy and chemical industry, mining and processing of minerals and mechanical engineering, quality of life, metalworking and woodworking. four main scenarios of investment impulses in the constructed factors were also evaluated. The growth of investment flows in the “quality of life” factor was chosen as the optimality criterion. It was revealed that the development of metal- and wood-processing provides the biggest positive effect. The conducted research shows the importance of investment synergy studying and describes a methodological approach to perform calculations.

Concurrent measures of impulsive action and choice are partially related and differentially modulated by dopamine D1- and D2-like receptors in a rat model of impulsivity

Impulsivity is a multidimensional construct, but the relationships between its constructs and their respective underlying dopaminergic underpinnings in the general population remain unclear. A cohort of Roman high- (RHA) and low- (RLA) avoidance rats were tested for impulsive action and risky decision-making in the rat gambling task, and then for delay discounting in the delay-discounting task to concurrently measure the relationships among the three constructs of impulsivity using a within-subject design. Then, we evaluated the effects of dopaminergic drugs on the three constructs of impulsivity, considering innate differences in impulsive behaviors at baseline. Risky decision-making and delay-discounting were positively correlated, indicating that both constructs of impulsive choice are related. Impulsive action positively correlated with risky decision-making but not with delay discounting, suggesting partial overlap between impulsive action and impulsive choice. RHAs showed a more impulsive phenotype in the three constructs of impulsivity compared to RLAs, demonstrating the comorbid nature of impulsivity in a population of rats. Amphetamine increased impulsive action and had no effect on risky decision-making regardless of baseline levels of impulsivity, but it decreased delay discounting only in high impulsive RHAs. In contrast, while D1R and D3R agonism as well as D2/3R partial agonism decreased impulsive action regardless of baseline levels of impulsivity, D2/3R agonism decreased impulsive action exclusively in high impulsive RHAs. Irrespective of baseline levels of impulsivity, risky decision-making was increased by D1R and D2/3R agonism but not by D3R agonism or D2/3R partial agonism. Finally, while D1R and D3R agonism, D2/3R partial agonism and D2R blockade increased delay discounting irrespective of baseline levels of impulsivity, D2/3R agonism decreased it in low impulsive RLAs only. These findings indicate that the acute effects of dopamine drugs were partially overlapping across dimensions of impulsivity, and that only D2/3R agonism showed baseline-dependent effects on impulsive action and impulsive choice.

GMM-Based Symbol Error Rate Analysis for Multicarrier Systems With Impulsive Noise Suppression

Theoretical analysis of orthogonal frequency division multiplexing (OFDM) systems, equipped at the receiver by a non-linear impulsive noise suppressor, is very challenging. Indeed, although an exact closed-form expression for the output signal-to-noise ratio (SNR) of such OFDM systems is available for widely used impulsive noise models, theoretical analysis of the associated symbol error rate (SER) is still open. The analytical SER available in the literature, exploit a Gaussian approximation of the non-linear distortion noise, which however holds true only under specific conditions. Conversely, this work develops an accurate analytical closed-form expression of the distortion noise distribution at the nonlinearity output, as well as its approximation by a Gaussian mixture model (GMM). By using GMMs we unify the SER analysis for communication systems equipped by non-linear impulsive noise suppressors, typically also used in vehicular communications. Closed form expressions for the SER are derived both for non-fading and frequency-selective Rayleigh/Rician fading channels affected by impulsive noise, which is also modeled by a GMM, including Bernoulli-Gaussian (BG), Middleton Class-A, and alpha-stable noises. Theoretical SER performance are compared with simulations, showing very good agreement for all the impulsive noise scenarios and the non-linear suppressors.

Nanoflare Heating of the Solar Corona Observed in X-Rays

The existence of the million-degree corona above the cooler photosphere is an unsolved problem in astrophysics. Detailed study of the quiescent corona that exists regardless of the phase of the solar cycle may provide fruitful hints toward resolving this conundrum. However, the properties of heating mechanisms can be obtained only statistically in these regions due to their unresolved nature. Here, we develop a two-step inversion scheme based on the machine-learning scheme of Upendran & Tripathi (2021a) for the empirical impulsive heating model of Pauluhn & Solanki (2007), and apply it to disk integrated flux measurements of the quiet corona as measured by the X-ray solar monitor on board Chandrayaan-2. We use data in three energy passbands, viz, 1–1.3, 1.3–2.3, and 1–2.3 keV, and estimate the typical impulsive event frequencies, timescales, amplitudes, and the distribution of amplitudes. We find that the impulsive events occur at a frequency of ≈25 events per minute with a typical lifetime of ≈10 minutes. They are characterized by a power-law distribution with a slope α ≤ 2.0. The typical amplitudes of these events lie in an energy range of 1021–1024 erg, with a typical radiative loss of about ≈103 erg cm−2 s−1 in the energy range of 1–2.3 keV. These results provide further constraints on the properties of subpixel impulsive events in maintaining the quiet solar corona.

Building patterns and fuel features drive wildfire severity in wildland-urban interfaces in Southern Europe

Fire danger analysis is crucial for landscape planning, which is particularly relevant in vulnerable areas such as the wildland-urban interface (WUI). The aim of our work is to investigate the capacity of fuel characteristics to predict burn severity in different WUI typologies classified according to nearby building density criteria. To achieve this goal, we selected 23 wildfires across Southern Europe, in which we differentiated non WUI areas, isolated, scattered, dense and very dense WUIs. Moreover, we spatialized burn severity and different fuel metrics using multispectral and radar satellite imagery. This information was used to analyze burn severity, and to identify its drivers in the different WUI typologies through analysis of variance, correlation analysis and machine learning models. Our results indicate that burn severity is lower in WUIs of clustered buildings than in non-WUI areas, which were also the most homogeneous in terms of vegetation cover. Moreover, we found that vegetation biophysical properties related to the amount of living fuel (fraction of vegetation cover and fraction of absorbed photosynthetically active radiation) showed the highest influence on burn severity in all WUI typologies. We also found that burn severity is less predictable in dense and very dense WUIs than in the rest, which can be attributed to their greater landscape complexity, presence of artificial structures and efficiency of extinction efforts. Our results serve to guide landscape management strategies, and impulse next-generation fire danger models, which should be based not only on synoptic fire weather indices but also on landscape-scale susceptibility to severe fires.

Locomotion performance for oscillatory swimming in free mode

Oscillatory swimming of a fishlike body, whose motion is essentially promoted by the flapping tail, has been studied almost exclusively in axial mode under an incoming uniform stream or, more recently, self-propelled under a virtual body resistance. Obviously, both approaches do not consider the unavoidable recoil motions of the real body which have to be necessarily accounted for in a design procedure for technological means. Actually, once combined with the prescribed kinematics of the tail, the recoil motions lead to a remarkable improvement on the resulting swimming performance. An inviscid impulse model, linear in both potential and vortical contributions, is a proper tool to obtain a deeper comprehension of the physical events with respect to more elaborated flow interaction models. In fact, at a first look, the numerical results seem to be quite entangled, since their trends in terms of the main flapping parameters are not easy to be identified and a fair interpretation is obtained by means of the model capability to separate the effects of added mass and vortex shedding. Specifically, a prevailing dependence of the potential contribution on the heave amplitude and of the vortical contribution on the pitch amplitude is instrumental to unravel their combined action. A further aid for a proper interpretation of the data is provided by accounting separately for a geometrical component of the recoil which is expected to follow from the annihilation of any spurious rigid motion in case no fluid interactions occur. The above detailed decomposition of the recoil motions shows, through the numerical results, how the single components are going to influence the main flapping parameters and the locomotion performance as a guide for the design of biomimetic swimmers.

Imaging the Photodissociation Dynamics and Fragment Alignment of CH2BrI at 193 nm.

The photodissociation dynamics and photofragment alignment of bromoiodomethane (CH2BrI) have been studied at 193 nm using a double experimental and theoretical approach. In addition, the ultraviolet (UV)-vacuum ultraviolet (VUV) absorption spectrum of gas phase CH2BrI has been measured in the photon energy range of 5-11 eV using the VUV Fourier transform spectrometer (FTS) at the VUV beamline DESIRS of the synchrotron SOLEIL facility. The slice imaging technique in combination with resonance enhanced multiphoton ionization (REMPI) detection of the Br(2PJ) and I(2PJ) (with J = 3/2 and 1/2 for Br/I and Br*/I*, respectively) atomic photofragments have been used to produce experimental translational energy and angular distributions, which were analyzed to deliver, on one hand, the partitioning of the available energy among the different degrees-of-freedom of the photofragments and, on the other, the photofragment polarization in terms of aqk(p) alignment parameters. The experimental measurements were rationalized in terms of high-level ab initio calculations of vertical excitation energies, transition dipole moments and potential energy curves (PECs) along different reaction coordinates to provide a complete picture of the photodissociation dynamics. The results indicate that for excitation at 193 nm, prompt C-X cleavage (with X being either halogen atom, Br or I) competes with fast internal conversion and consequent stochastic dissociation in lower electronic states. In the case of the CH2Br + I(2P3/2)/I*(2P1/2) channels, the dynamics are greatly biased toward the stochastic dissociation process due to both the particular PECs landscape and the unfavored excitation of the CH2BrI ensemble with respect to the C-I molecular axis at this excitation energy. The ab initio PECs provide a tentative path for the fast dissociation process in either case. For the C-Br bond breakage, excitation to the 13A' electronic state and predissociation through the 11A'/11A″ or 12A'/12A″ states, leading to direct dissociation through the 10A'/9A″ states, appear as the most consistent dynamics. For the C-I channel, predissociation does not become a reliable possibility and a fast internal conversion may precede dissociation through the repulsive 6A'/6A″ and 4A'/4A″ states. The large content of rotational and vibrational excitation of the polyatomic cofragments is justified through the soft impulsive model and the geometrical changes produced along the dissociation pathway. Strikingly, the aqk(p) alignment parameters obtained for the Br(2P3/2) and I(2P3/2) photoproducts indicate that the rotational angular momentum of the CH2X (X = I or Br) cofragment appears highly constrained along the recoil direction. Finally, this work presents a highly plausible explanation for the branching ratio of secondary dissociation processes in the photodynamics of CH2BrI at 193 nm.

Impulsive time series modeling with application to luteinizing hormone data.

This work considers the estimation of impulsive time series pertaining to biomedical systems and, in particular, to endocrine ones. We assume a signal model in the form of the output of a continuous linear time-invariant system driven by a sequence of instantaneous impulses, which concept is utilized here, in particular, for modeling of the male reproductive hormone axis. An estimation method to identify the impulsive sequence and the continuous system dynamics from sampled measurements of the output is proposed. Hinging on thorough mathematical analysis, the method improves upon a previously developed least-squares algorithm by resolving the trade-off between model fit and input sparsity, thus removing the need for manual tuning of user-defined estimation algorithm parameters. Experiments with synthetic data and Markov chain Monte-Carlo estimation demonstrate the viability of the proposed method, but also indicate that measurement noise renders the estimation problem ill-posed, as multiple estimates along a curve in the parameter space yield similar fits to data. The method is furthermore applied to clinical luteinizing hormone data collected from healthy males and, for comparability, one female, with similar results. Comparison between the estimated and theoretical elimination rates, as well as simulation of the estimated models, demonstrate the efficacy of the method. The sensitivity of the impulse distribution to the estimated elimination rates is investigated on a subject-specific data subset, revealing that the input sequence and elimination rate estimates can be interdependent. The dose-dependent effect of a selective gonadotropin releasing hormone receptor antagonist on the frequency and weights of the estimated impulses is also analyzed; a significant impact of the medication on the impulse weights is confirmed. To demonstrate the feasibility of the estimation approach for other hormones with pulsatile secretion, the modeling of cortisol data sets collected from three female adolescents was performed.

Almost Periodic Solution for Forced Perturbed Non-Instantaneous Impulsive Model

In this paper we investigate a forced perturbed non-instantaneous impulsive model. Firstly, we prove the existence and uniqueness of an almost periodic solution for the model considered by the Banach contraction principle. Secondly, we prove that all solutions converge exponentially to the almost periodic solution. In other words, the solution of the model considered is exponentially stable. Finally, we provide some simulations to show the effectiveness of the theoretical results.

Comprehensive coverage of particle acceleration and kinetic feedback from the stellar mass black hole V404 Cygni

ABSTRACT We present analysis of comprehensive radio observations of the black hole V404 Cyg during its 2015 outburst. These data represent the best ever coverage of jet production and particle acceleration from any black hole. We report for the first time a clear and near-linear flux–rms correlation in the radio flux densities. Investigation of individual flares reveals in nearly all cases the peak corresponds to the transition from optically thick to thin to synchrotron emission, but an extended phase of particle acceleration is required in contrast to simple impulsive injection models. The largest radio flare is preceded by a phase of optical oscillations and followed one day later by a smaller but optically thin flare, likely due to ejecta interacting with the interstellar medium. Comparing the radio emission to contemporaneous X-ray and optical data, we find that the X-ray and radio measurements are correlated on all time-scales from seconds to one day. Correlation with the optical flux densities is weak at short time-scales, but becomes significant on time-scales greater than a few hours. We evaluate the physical conditions (size, magnetic field, and internal energy) associated with 86 individual radio flares, which in turn allows us to place a lower limit on the kinetic feedback over the 15 d of intense activity. If this energy was deposited locally to the source, as implied by the failure to detect jets on angular scales larger than milliarcsec, then we predict that a nova-like shell could have been formed.

Large-amplitude effects on interface perturbation growth in Richtmyer–Meshkov flows with reshock

Experimental and theoretical studies on the Richtmyer–Meshkov (RM) instability of heavy/light gaseous interfaces with reshock are performed. Both small and large initial perturbation amplitudes of single- and quasi-single-mode interfaces are considered, highlighting the effects of interface amplitude and shape on the linear and nonlinear growths of the RM instability. The results indicate that for small-amplitude interfaces distorted before and after the first reshock arrival, the perturbation growths at linear stages can be well predicted by the impulsive model. For large-amplitude interfaces, however, the reshock acceleration on the evolving interface promotes the mode interaction and enhances the nonlinear effects, making the perturbation growth rates reduced in comparison with those in the singly shocked cases. The complete evolution, especially the bubble evolution, has a strong memory of initial shapes, while for large-amplitude cases, the spike evolution is nearly independent of them owing to the destruction of large-scale vortices and multiple-shock-induced small-scale structures. Compared with that of the single-mode case, the normalized perturbation growths after reshock for the quasi-single-mode cases are more sensitive to initial amplitudes. To better describe the linear growth rates of the RM instability induced by the incident shock and reshock, the reduction factor models for large-amplitude cases are developed, which successfully predict the non-monotonic dependence of linear growth rates on initial perturbation amplitudes. For small-amplitude cases, the nonlinear model proposed for the singly shocked case can predict the reshocked nonlinear growth, while for large-amplitude cases, it is invalid because the perturbation growth shows a linear characteristic after reshock.

Analyzing stability of equilibrium points in impulsive neural network models involving generalized piecewise alternately advanced and retarded argument

In this paper, we investigate the models of the impulsive cellular neural network with piecewise alternately advanced and retarded argument of generalized argument (in short IDEPCAG). To ensure the existence, uniqueness and global exponential stability of the equilibrium state, several new sufficient conditions are obtained.The method is based on utilizing Banach's fixed point theorem and a new IDEPCAG's Gronwall inequality.The criteria given are easy to check and when the impulsive effects do not affect, the results can be extracted from those of the non-impulsive systems.Typical numerical simulation examples are used to show the validity and effectiveness of proposed results.

Impulsivity and Perpetration of Intimate Partner Aggression: The Moderating Effects of Negative Affective State and Alcohol

Background: The goal of this study was to test the interactive effects of negative urgency, state negative affect, and alcohol intoxication on intimate partner aggression (IPA) perpetration. Methods: Heavy drinkers who recently perpetrated IPA completed self-report measures of impulsivity, were administered an alcohol or control beverage, and completed a laboratory aggression task. State negative affect was assessed unobtrusively via the Facial Action Coding System. Results: Consistent with our prediction, negative urgency was significantly and positively related to IPA when state negative affect was also high, but this relation was not significant when state negative affect was low. Conclusions: These results have implications for understanding the role of negative affect and impulsivity in IPA perpetration and for understanding trait models of impulsivity in general.

Analysis of impulsive stochastic delay budworm population model with L$$\acute{\mathrm {e}}$$vy jumps

Analysis of impulsive stochastic delay budworm population model with L$$\acute{\mathrm {e}}$$vy jumps

Understanding Chinese Consumers' Livestreaming Impulsive Buying: An Stimulus-Organism-Response Perspective and the Mediating Role of Emotions and Zhong Yong Tendency.

We built a livestreaming impulsive buying model based on stimulus-organism-response (SOR) theory, and we explored the impact of atmospheric cues (ACELS) and sales promotion (SPELS) on impulsive buying (IBI) based on emotions (EOC) and Zhong Yong tendency (ZYT) of online consumers. Combined with holistic orientation, perspective integration, and harmony maintenance, ZYT is a cognitive process involving individual events. We gathered 478 samples using a questionnaire to test the proposed research model. The empirical findings show that as the stimuli in the livestreaming environment, ACELS and SPELS during livestreaming greatly boost EOC while significantly constraining consumers’ ZYT. Among online consumers, positive EOC promotes IBI, whereas ZYT dampens it. In addition, EOC and ZYT mediate the relationship between stimulus factors and response factors in parallel, resulting in four model mediation paths. By incorporating the SOR model, this study provides theoretical underpinnings for the role of cognitive processing in impulsive purchases, as well as useful guidance for e-commerce platforms and streamers to effectively understand Chinese consumers’ purchase behavior, which benefits the development of effective promotion strategies and the creation of powerful marketing tools.

Lightning impulse modeling and simulation of dry-type and oil-immersed power- and distribution transformers

This paper presents in detail numerical methods and techniques for lightning impulse (LI) modeling and simulation of power and distribution transformers. The modeling methods are based on equivalent circuits of transformer winding entities resulting from the initial winding discretization determined by the required accuracy. The parameters of the equivalent circuit such as resistances and self- and mutual capacitances and inductances are obtained from field simulations (FEM). The circuit equations of the transformer’s equivalent circuit written in the state space form yield a large system of differential equations that is solved in time-domain by using the standard Runge-Kutta numerical integration technique. The obtained solution represents the voltage distribution over the winding in each moment of the LI-time (50μs). The results verification by comparison against measurements is presented in detail.

On stability of nonzero set-point for nonlinear impulsive control systems

The interest in non-linear impulsive systems (NIS) has been growing due to their impact on application problems such as disease treatments (diabetes, HIV, influenza, COVID-19, among many others), where the control action (drug administration) is given by short-duration pulses followed by time periods of null values. Within this framework, the concept of equilibrium needs to be extended (redefined) to allow the system to keep orbiting (between two consecutive pulses) in some state-space sets out of the origin, according to the usual objectives of most real applications. Although such sets can be characterized by means of a discrete-time system obtained by sampling the NIS at the impulsive times, no agreement has been reached on their asymptotic stability (AS) under optimizing control strategies. This paper studies the asymptotic stability of control equilibrium orbits for NIS, based on the underlying discrete-time system, in order to establish the conditions under which the AS for the latter leads to the AS for the former. Furthermore, based on the latter AS characterization, an impulsive Model Predictive Control (i-MPC) that feasibly stabilizes the non-linear impulsive system is presented. The biomedical problems of intravenous bolus administration of Lithium and antiretrovirals administration for HIV treatments are considered as simulation examples to demonstrate the controller performance

Reduction of symptom after a combined behavioral intervention for reward sensitivity and rash impulsiveness in internet gaming disorder: A comparative study

Impulsivity is both a core symptom and a key psychological mechanism in Internet Gaming Disorder (IGD), and therefore interventions for impulsivity in IGD have both theoretical and practical value. However, previous related interventions only tended to focus on a single factor of impulsivity and achieved inconsistent results. In this study, based on the theory of two-factor model of impulsivity (reward sensitivity and rash impulsiveness), four groups of IGD subjects were recruited to investigate whether there were different effects of single rash impulsiveness or reward sensitivity intervention versus a combined intervention. By comparing the different factors of impulsivity of the four groups before and after a 15-day intervention, the results showed that: (1) compared with the control group, subjects in the Go/No-go training group only had a significantly lower level of rash impulsiveness, subjects in the Stimulus-Response Compatibility (SRC) training group only had a significantly lower level of reward sensitivity, and subjects in the combined training group had significantly lower levels of both impulsivity; (2) among the three intervention groups, only the subjects in the combined training group had significantly lower IGD scores in the follow-up measure. This study indicated that the behavioral training of Go/No-go and SRC were effective in improving rash impulsiveness and reward sensitivity in IGD, respectively, but the intervention effect of the combined training was better than that of the single training.

Synchronization of Epidemic Systems with Neumann Boundary Value under Delayed Impulse

This paper reports the construction of synchronization criteria for the delayed impulsive epidemic models with reaction–diffusion under the Neumann boundary value. Different from the previous literature, the reaction–diffusion epidemic model with a delayed impulse brings mathematical difficulties to this paper. In fact, due to the existence of second-order partial derivatives in the reaction–diffusion model with a delayed impulse, the methods of first-order ordinary differential equations from the previous literature cannot be effectively applied in this paper. However, with the help of the variational method and an appropriate boundedness assumption, a new synchronization criterion is derived, and its effectiveness is illustrated by numerical examples.