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This paper is mainly concerned with the new types of entire solutions which are different from pulsating fronts of Lotka-Volterra competition systems with asymmetric dispersal in spatially periodic habitats. The asymmetry of kernel function leads to a great influence on the profile of pulsating fronts and the sign of wave speeds, which gives rise to the properties of the entire solution more complex and diverse. We first give a relationship between the critical speeds c ⁎ ( ξ ) and c ⁎ ( − ξ ) , corresponding to the minimal speeds of two pulsating fronts propagating in the direction of ξ and −ξ, respectively. Then, the exponential behavior of pulsating fronts as they approach their limiting states is obtained. Finally, by considering the interactions of two different pulsating fronts coming from two opposite/same directions and applying the super-/subsolutions techniques as well as the comparison principle, we establish the existence and various qualitative properties of some different types of entire solutions defined for all time and whole space. Moreover, we give some numerical simulations to describe intuitively these obtained entire solutions.

Background: Starter cultures are essential in food industry biotechnology, consisting of microorganism preparations inoculated to produce safe fermented foods with desirable sensory characteristics. Objective: This study aims to identify and analyze the growth and flow of knowledge regarding starter cultures by creating scientific and technological profiles using patentometric and bibliometric indicators. Methods: A search for patents and scientific articles was conducted in December 2020 following a proposed 10-step methodology using the Scopus® and Patentinspiration databases. The search strategy was based on the keywords “starter culture” and “fermentation” considering publications up to 2020. Results: A total of 3035 articles and 719 patents were published until 2020, presenting a more significant number in the last ten (10) years due to the development of biological sciences and molecular biology involving enzymes and microorganisms. Italy leads the scientific production while China leads the technological. It was also possible to determine the most productive author and inventors, the most influential articles and inventions, and the main scientific journals and patent offices. Conclusion: Scientific and technological activities have an exponential behavior showing that the knowledge about starter cultures continues to grow, becoming a field of interest for optimizing industrial processes related to food fermentation, thus achieving diversification of products that can satisfy the demand for food in an increasingly competitive global market.

Noninvasive and convenient measurement of vascular stiffness is of considerable importance for early detection and treatment of arteriosclerosis. Volume elastic modulus ( $${E}_{{v}}$$ ) is one of representative measures reflecting effective vascular elasticity that is strongly dependent upon blood pressure (BP) or transmural pressure ( $${P}_{{t}{r}}$$ = mean BP – (externally applied pressure)). However, its nonlinear nature in terms of functional form has not been fully investigated in human vasculature. This paper therefore seeks to clarify the functional form of $${E}_{{v}}({P}_{{t}{r}})$$ in the human finger and radial arteries based on photoplethysmographic volume-oscillometry developed for novel indirect BP measurement. Using a smartphone-based instrument specially designed for this study, $${E}_{{v}}$$ values at various $${P}_{{t}{r}}$$ levels were obtained in 11 male and female volunteers with various ages. It was demonstrated that $${E}_{{v}}({P}_{{t}{r}})$$ showed an exponential behavior with respect to $${P}_{tr}$$ changes, expressed as $${E}_{{v}}({P}_{{t}{r}})={E}_{{v}0}\bullet {e}{x}{p}(\alpha \bullet {P}_{{t}{r}})$$ ( $${E}_{{v}0}$$ , α; constant) with a high coefficient of determination, the validity of which was also supported through theoretical derivation. Conclusively, the $${E}_{{v}}({P}_{{t}{r}})$$ is found to increase exponentially with arterial distending pressure, and the independent measures $${E}_{{v}0}$$ and α would be useful parameters to conveniently evaluate progressive changes of vascular stiffness among and/or within individuals, indicating that this measurement has potential for arteriosclerosis screening (200/200). Schematic diagram of overall configuration of the measurement system of arterial elasticity in the finger and the wrist, consisting of a measuring, signal processing and control (MSC) unit (surrounded by the dashed line) and a smartphone for data display and storage. An occlusive cuff and a photoplethysmographic placement of LED and PD for the finger and the wrist are shown in the upper middle part. Measurement scenes of the finger and the wrist are also inset in the upper left and in the upper right part, respectively.

We study in this article, a stochastic evolution equation for the motion of magneto-fluid filling a periodic domain of R3: The existence and uniqueness of stationary solution is established and the...

In this article, we study the exponential behavior of 3D stochastic primitive equations driven by fractional noise. Since fractional Brownian motion is essentially different from Brownian motion, the standard method via classic stochastic analysis tools is not available. Here, we develop a method which is close to the method from dynamic system to show that the weak solutions to 3D stochastic primitive equations driven by fractional noise converge exponentially to the unique stationary solution of primitive equations. This method may be applied to other stochastic hydrodynamic equations and other noises including Brownian motion and Levy noise.

espanolObjetivo: Comparar dos modelos epidemiologicos matematicos deterministicos de la literatura, para simular la curva de decesos en el departamento del Atlantico causados por el COVID-19. Metodologia: El primer modelo propuesto para simular el numero de decesos por el COVID-19 es el de Tappe. Este enfoque se basa en el comportamiento exponencial de la curva del numero de decesos, e inicialmente fue usado por el autor con los datos disponibles del numero de muertos en China. El otro modelo propuesto es el SIRD, una extension del modelo SIR, que divide la poblacion entre susceptibles, infectados, muertos y recuperados. Resultados: Los resultados obtenidos a partir de los dos modelos, en las fechas estipuladas, mostraron que, comparados con los datos tomados del INS, ambos describen un comportamiento relativamente similar. Sin embargo, al analizar una proyeccion realizada para noventa dias, treinta dias despues de la fecha final de analisis (26 de mayo), se observa que el modelo SIRD describe una curva de crecimiento mayor que la del modelo de Tappe, esto se debe, probablemente, a la insercion de mas variables en el modelo. Conclusiones: Al ser SIRD un modelo mas completo, con mayor numero de variables representativas de la poblacion, la proyeccion realizada con este es mas confiable que la realizada con el modelo de Tappe. Para estudios futuros se pretende incorporar la poblacion de los expuestos para describir el numero de decesos, en un modelo SEIRD, en este departamento EnglishObjective: To compare two deterministic mathematical epidemiological models from the literature, to simulate the death curve in the Atlantic department caused by COVID-19. Methodology: The first model proposed to simulate the number of deaths by COVID-19 is that of Tappe. This approach is based on the exponential behavior of the death number curve, and was initially used by the author with the available data on the number of deaths in China. The other model proposed is the SIRD, an extension of the SIR model, which divides the population between susceptible, infected, dead and recovered. Results: From the obtained results of both models, comparing with the available data from INS, both models reach similar behavior. However, when analyzing the projection for the next 30 days from the 26th may, it is observed that the curve of number of deaths is greater in the SIRD model than the Tappe’s model, probably due to the adding of more variables on the model. Conclusions: As SIRD is a more complete model that involves a wide number of variables of population, the projection made with this model is more reliable than that made with the Tappe’s model. For future studies, the aim is to incorporate the population of those exposed to describe the number of deaths, in a SEIRD model, in the department of Atlantico.

In this article, we are concerned with the neutral impulsive stochastic integro-differential equations driven by Poisson jumps and Rosenblatt process. By using resolvent operator and some analysis techniques, we ensure existence and uniqueness of solutions. Further, we investigate exponential stability of mild solutions. We have also given an example to illustrate our theoretical results.

Water quality parameters help to decide the further use of water based on its quality. Changes in water surface area in the lake shall affect the water quality. Chlorophyll a, Nitrate concentration and water turbidity were extracted from satellite images to record each variation on these parameters caused by the water amount in the lake changes. Each water quality measures have been recorded with its surface area reading to analyses the effects. Water quality parameters were estimated from Sentinel-2 sensor based on the satellite temporal resolution for the years 2017–2018. Data were pre-processed then processed to estimate the Maximum Chlorophyll Index (MCI), Green Normalized Difference Vegetation Index (GNDVI) and Normalized Difference Turbidity Index (NDTI). The Normalized Difference Water Index (NDWI), was used to calculate and record the changes in the water surface area in Baysh dam lake. Results showed different correlation coefficients between the lake surface area and the water quality parameters estimated Remote Sensing data. The response of the water quality parameters to surface water changes was expressed in four different surface water categories. MCI is more sensitive to surface water changes rather than GNDVI and NDTI. Neural network Analysis showed a resemblance between GNDVI and NDTI expressed in sigmoidal function while MCI showed a different behavior expressed in exponential behavior. Therefore, monitoring of the surface water area of the lack is essential in water quality monitoring.

In this paper, we study the stability of quasilinear parabolic stochastic partial differential equations with multiplicative noise, which are neither monotone nor locally monotone. The exponential mean square stability and pathwise exponential stability of the solutions are established. Moreover, under certain hypothesis on the stochastic perturbations, pathwise exponential stability can be derived, without utilizing the mean square stability.

En el presente trabajo se realizó la simulación del comportamiento plasmónico de nanoesferas de oro con diámetros de 10, 20, 30, 40, 50 y 60 nm en medio acuoso frente a la luz en el rango de longitudes de onda de 400 a 650 nm. Se observó una mayor contribución de la dispersión al espectro de extinción en función del tamaño de nanoesferas, el cual presentó un comportamiento exponencial.

This paper discusses the unique patterns evolved through phase separation of a bulk liquid crystal (LC) from the self-assembly of lysozyme induced by evaporation of de-ionized water only. Each domain shows a central dark region surrounded by bright regions (randomly oriented LC droplets). The birefringence intensity reveals three regimes (a slow increase, rapid rise, then saturation) not seen without LC droplets. The textural study exhibits a simple exponential behavior that changes as a function of LC concentration. Furthermore, in the presence of LC, the crack patterns are found to be different near the drop edge than those in the central region.

In this paper, we use the fractional conformable derivative to analyze the classical Drude model with direct DC and alternating current AC. We apply the conformable Laplace transform to solve the corresponding equations and found that the electron current density in the DC case has a stretched exponential behavior, while in the AC case shows an exponential-like down-chirp response. It is shown that the conformable fractional Laplace transform is a powerful method to solve fractional linear differential equations with constant coefficients. The solutions of the corresponding classical model are recovered as particular cases, when γ = 1.

The way in which the Root Mean Square of the Successive Differences between adjacent RR intervals (RMSSD) recovers immediately after exercise could be a good indicator of internal training load (ITL). The aim of this study is to design a recovery index based on RMSSD. Forteen healthy men took part in this study. The experiment lasted 2 weeks, with 4 separate (48 - 72 h) sessions. First session was an incremental treadmill test to determine ventilatory thresholds (VT1 and VT2) and maximal aerobic speed (MAS). Each subject ran at VT1 speed (second day), VT2 speed (third day) and a time-to-exhaustion test at MAS (fourth day). The duration of VT1 and VT2 loads was selected in such a way that the product intensity-duration (training load) was the same. HRV was measured from 10’ prior to test (Rest) to 30’ after completed (Recovery). Recovery slopes were calculated from RMSSD values at 10 and 30 minutes. Borg scale was recorded at the end of every test and the Training Impulse (TRIMP) values were calculated using Banister equations. The RMSSD values dropped substantially regardless of the intensity and the duration of exercise (average 4 ms). The RMSSD recovery was linear during the 30 min and different depending on the intensity of exercise. To propose a recovery index, we calculated the slope of RMSDD over the 30 minutes (slope-30) and also the first 10 minutes (slope-10). Given that the slopes presented an exponential behavior in relation with effort intensity, three curves were obtained (average values, plus SD and minus SD) defining a nomogram. For practical application, we propose: 1) to measure RMSSD the last 5 minutes of exercise and any period of 5 minutes during the first 30 minutes recovery; 2) to calculate the slope of RMSSD between exercise and recovery; 3) to compare with the nomogram.

Objective: In this study, it is aimed to provide a dynamic structure to the summary status and analysis results based on the current COVID-19 data of the countries based on changing status of global COVID-19 outbreak in the world and in Turkey; thus, to support fast and proactive decisions. In this scope, to define COVID-19 based on data, an online R-Shiny application is developed (https://elifkartal.shinyapps.io/covid19/). Material and Method: In this study, CRoss-Industry Standard Process for Data Mining - CRISP-DM is used as the study method. The changing situation of COVID-19 in global and national dimensions was evaluated. New variables are calculated such as Linear Change Rate (LCR), Exponential Growth Coefficient (EGC), and required days to double cases. Cluster analysis was performed by applying the k-Means data mining algorithm to the data reinforced with the new variables and similarities of countries were determined. The countries closest to the cluster average are accepted as cluster centers and the countries in the same cluster are ranked according to their distance from the cluster center. Results: One of the most important findings of the study is that the trends of LCR and EGC are the same. As such, it can be said that COVID-19 does not display an exponential behavior or can be controlled. With the developed application, the countries in which the cluster is located, regardless of their geographical location and dynamically according to time, the possible risk situations and similarities of the countries in the same cluster have been determined more precisely. Conclusion: With this study and the application developed; depending on changing status of global COVID-19 outbreak in the world and in Turkey, a dynamic structure has been given to the summary status and analysis results based on the current COVID-19 data of the countries, thus, it has been provided to support fast and proactive decisions., Amaç: Bu çalışmanın amacı; küresel COVID-19 salgınının dünyada ve Türkiye’de değişen durumuna bağlı olarak ülkelere ait güncel COVID-19 verisine dayalı özet durum ve analiz sonuçlarına dinamik yapı kazandırılması, böylelikle hızlı ve proaktif kararlara destek verilebilmesidir. Bu kapsamda, COVID-19’u veriye dayalı olarak tanımlamak amacıyla öncelikle çevrimiçi bir R-Shiny uygulaması geliştirilmiştir (https://elifkartal.shinyapps.io/covid19/). Gereç ve Yöntem: Bu çalışmada yöntem olarak Veri Madenciliği için Çapraz Endüstri Standart Süreç Modeli (CRoss-Industry Standard Process for Data Mining - CRISP-DM) kullanılmıştır. Küresel ve ülkesel boyutta COVID-19’un değişen durumu değerlendirilmiştir. Doğrusal Değişim Oranı (DDO), Üstel Büyüme Katsayısı (ÜBK) ve vaka sayısının ikiye katlanması için gereken gün sayısı gibi yeni değişkenler hesaplanmıştır. Böylece, yeni değişkenlerle güçlendirilen veriye k-Ortalamalar veri madenciliği algoritması uygulanarak kümeleme analizi yapılmış ve ülkelerin benzerlikleri belirlenmiştir. Küme ortalamasına en yakın ülkeler küme merkezi olarak kabul edilmiş, aynı kümedeki ülkeler küme merkezine olan uzaklıklarına göre sıralanmıştır. Bulgular: Çalışmanın en önemli bulgularından biri ÜBK ve DDO eğilimlerinin aynı olmasıdır. Bu haliyle COVID-19’un salgın özelliği olarak kabul edilen üstel bir davranış göstermediği veya kontrol altına alınabildiği söylenebilecektir. Geliştirilen uygulamayla ülkelerin, coğrafi konumlarından bağımsız ve zamana göre dinamik bir biçimde, hangi kümede yer aldığı, aynı kümedeki ülkelerin olası risk durumları ve benzerlikleri daha hassas biçimde belirlenmiştir. Sonuç: Bu çalışma ve geliştirilen uygulama ile; küresel COVID-19 salgınının dünyada ve Türkiye’de değişen durumuna bağlı olarak ülkelere ait güncel COVID-19 verisine dayalı özet durum ve analiz sonuçlarına dinamik yapı kazandırılmış, böylelikle hızlı ve proaktif kararlara destek verilebilmesi sağlanmıştır.

Time dependent reproduction number (Rt) is one of the most popular parameters to track the impact of COVID-19 pandemic. However, especially at the initial stages, Rt can be highly underestimated because of remarkable differences between the actual number of infected people and the daily incidence of people who are tested positive. Here, we present the analysis of daily cumulative number of hospitalized (HP) and intensive care unit (ICU) patients both in space and in time in the early phases of second wave COVID-19 pandemic across eight different European countries, namely Austria, Belgium, Czech Republic, France, Italy, Portugal, Spain, and United Kingdom. We derive simple model equations to fit the time dependence of these two variables where exponential behavior is observed. Growth rate constants of HP and ICU are listed, providing country-specific parameters able to estimate the burden of SARS-COV-2 infection before extensive containment measures take place. Our quantitative parameters, fully related to hospitalizations, are disentangled from the capacity range of the screening campaign, for example the number of swabs, and they cannot be directly biased by the actual number of infected people. This approach can give an array of reliable indicators which can be used by governments and healthcare systems to monitor the dynamics of COVID-19 epidemic.

The study objective was to evaluate the performance of SAGAC in optimizing a linear mathematical model in whole variables to determine the most cost-effective solution in transporting cattle for slaughter. The model determines the choice of refrigerator truck, road (route), and an open-truck in a scripting process. The tests performed with the SAGAC algorithm for optimizing the proposed model were compared with the results obtained, under similar conditions, by the branch-and-bound method for solving entire problems and solving a problem optimally. After the first twenty-two experimental trials, for comparison between the two methods, nine more experimental trials were carried out, with an increase in the degree of complexity, only with the SAGAC algorithm. The results obtained in the first twenty-two experimental trials demonstrate an equivalent performance between the two methods, showing that the SAGAC algorithm, even though it is not a technique that guarantees optimal results, in this case, was also able to find them. The nine final experiments performed only by SAGAC showed satisfactory results, with an evolutionary curve of exponential behavior.

We give characterizations of the hyperbolicity of a nonautonomous one-sided dynamics defined by a sequence of linear operators, in terms of the hyperbolicity of an associated evolution map defined on a Banach space of sequences. We consider a large family of spaces of sequences besides $$L^p$$ spaces. Moreover, we discuss the general cases when the dynamics may be invertible only along the unstable direction and of a general nonuniform exponential behavior of the dynamics given by a sequence of norms instead of a single norm.

Hydrology and especially hydrological models often treat catchments as if they were leaky buckets. But, do we find such catchments in the real world or is this just a convenient simplification? Moreover, if we find them, what attributes allow these catchments to show such a simple behavior? To study this, we look at time series of 27 years for 90 catchments in Hesse, Germany, which includes droughts and years of abundant precipitation. In addition, the state Hesse provides a wide range of catchment attributes like geology, soils and land use, while still having a relatively similar climate. Using discharge, evapotranspiration and precipitation, we calculate the cumulative storage change for all years separately and use it as a proxy for the storage. We group the 90 catchments by the complexity of their storage-discharge relationship, which we define as how good the relationship can be modelled by an exponential function. We find that climate and physical attributes of the catchments seem to have similar influence on the overall complexity of the storage-discharge relationship. However, we could also identify catchments that depict consistent behavior, mostly independent of climate. Those catchments either behave always complex or always simple in all the years considered. They differ in their permeability, conductivity, geology, soil and to a lesser extent their shape. We show that bucket like catchments exist in the real world and that they can be found by looking for oval catchments with good permeability in regions of igneous geology and clay silt soil texture.

Characterizing the time-dependent mechanical properties of cells is not only necessary to determine how they deform, but also to fully understand how external forces trigger biochemical-signaling cascades to govern their behavior. Presently mechanical properties are largely assessed by applying local shear or compressive forces on single cells in isolation grown on non-physiological 2D surfaces. In comparison, we developed the microfabricated vacuum actuated stretcher to measure tensile loading of 3D multicellular ‘microtissue’ cultures. With this approach, we assessed here the time-dependent stress relaxation and recovery responses of microtissues, and quantified the spatial remodeling that follows step length changes. Unlike previous results, stress relaxation and recovery in microtissues measured over a range of step amplitudes and pharmacological treatments followed a stretched exponential behavior describing a broad distribution of inter-related timescales. Furthermore, despite a performed compendium of experiments, all responses led to a single linear relationship between the residual elasticity and degree of stress relaxation, suggesting that these mechanical properties are coupled through interactions between structural elements and the association of cells with their matrix. Lastly, although stress relaxation could be quantitatively and spatially linked to recovery, they differed greatly in their dynamics; while stress recovery behaved as a linear process, relaxation time constants changed with an inverse power law with step size. This assessment of microtissues offers insights into how the collective behavior of cells in a 3D collagen matrix generate the dynamic mechanical properties of tissues, which is necessary to understanding how cells deform and sense mechanical forces in the body.

In this paper, micro-damage mechanics (MIDM) and macro-damage mechanics (MADM) are employed to study the progressive damage in composite laminates. Firstly, a novel method for progressive damage modeling of composite laminates is proposed based on MADM rules. In the MADM method, a new exponential behavior for the softening regime of damaged plies is proposed from comprehensive experimental tests on glass/epoxy composite laminates with a variety of the stacking sequence. Then, a MIDM model is employed to study the mechanical behavior of composite laminates with micro-cracks. The effective elastic moduli and Poisson’s ratio in damaged composite laminates containing a large number of micro-cracks are determined by utilizing variational methods. Finally, the proposed exponential behavior of damaged plies based on MADM rules is verified by utilizing a MIDM model. The resulting coincidence of MADM and MIDM proves that the proposed method can accurately simulate the behavior of damaged plies in glass/epoxy composite laminates.

In this article, we study the stability of weak solutions to a stochastic version of a globally modified coupled Cahn–Hilliard–Navier–Stokes model with multiplicative noise. The model consists of the globally modified Navier–Stokes equations for the velocity, coupled with an Cahn–Hilliard model for the order (phase) parameter. We prove that under some conditions on the forcing terms, the weak solutions converge exponentially in the mean square and almost surely exponentially to the stationary solutions. We also prove a result related to the stabilization of these equations.

We consider the problem of whether the existence of a tempered exponential dichotomy for a linear dynamics can be deduced from the same property for the dynamics restricted to each diagonal entry. More generally, we consider this problem for a dynamics in block upper triangular form. We also obtain corresponding results for a strong tempered exponential dichotomy and for a discrete time dynamics.

A detailed kinetic study of the reduction of trans-[RuCl2(dipicOEt)2]-, where dipicOEt = dipicolinate mono ethyl ester anion, by L-ascorbic acid that leads to the formation of the corresponding Ru(II) complex, was carried out spectrophotometrically using the stopped-flow technique. The reaction was studied as a function of [AscH2]T and pH. The observed kinetic traces could only be fitted by a three-exponential function, characteristic for three parallel reaction paths. The complex was isolated as {[Na(H2O)2][trans-RuCl2(dipicOEt)2]}n of which a single crystal X-ray structure was determined. Detailed spectroscopic studies on the complex present in aqueous solution showed that under the selected experimental conditions only a single complex species is present in solution. The observed complication is suggested to arise from the low driving force of the reaction during which the re-oxidation of Ru(II) by the semi-oxidized L-ascorbic acid, i.e. ascorbyl radical Asc*-, accounts for the apparent three exponential behavior of the reaction. The results are in excellent agreement with those of a recent study on the same reaction for cis-dichloridobispicolinatoruthenate(III) (Eur. J. Inorg. Chem., 2016, 5380-5386).

We consider the problem of synthesizing a program given a probabilistic specification of its desired behavior. Specifically, we study the recent paradigm of distribution-guided inductive synthesis (digits), which iteratively calls a synthesizer on finite sample sets from a given distribution. We make theoretical and algorithmic contributions: (i) We prove the surprising result that digits only requires a polynomial number of synthesizer calls in the size of the sample set, despite its ostensibly exponential behavior. (ii) We present a property-directed version of digits that further reduces the number of synthesizer calls, drastically improving synthesis performance on a range of benchmarks.

We consider a generalization of the notion of exponential dichotomy in which the exponential behaviors on \(\mathbb {R}^+\) and \(\mathbb {R}^-\) need not agree at the origin, although they still satisfy a certain compatibility condition. A nontrivial example is the change from stable to unstable behavior in a given direction, such as in a saddle-node bifurcation. Our main aim is to show that this exponential behavior is robust, in the sense that it persists under sufficiently small linear perturbations. We emphasize that we consider arbitrary evolution families in Banach spaces. This includes any differentiable evolution family obtained from a nonautonomous linear equation \(x^{\prime } =A(t) x\) possibly with A(t) unbounded, although in general we do not require the evolution families to be differentiable.

We study the semilinear elliptic equation Δu + g(x, u, Du) = 0 in ℝ n . The nonlinearities g can have arbitrary growth in u and Du, including, in particular, exponential behavior. No restriction is imposed on the behavior of g(x, z, p) at infinity except in the variable x. We obtain a solution u which is locally unique and inherits many of the symmetry properties of g. Positivity and asymptotic behavior of the solution are also addressed. Our results can be extended to other domains, such as the half-space and exterior domains. Finally, we give some examples.

Proposed is a multicomponent model for the estimation of light-emitting diode (LED) lumen maintenance using test data that were acquired in accordance with the test standards of the Illumination Engineering Society of North America, i.e., LM-80-08. Lumen maintenance data acquired with this test do not always follow exponential decay, particularly data collected in the first 1000 h or under low-stress (e.g., low temperature) conditions. This deviation from true exponential behavior makes it difficult to use the full data set in models for the estimation of lumen maintenance decay coefficient. As a result, critical information that is relevant to the early life or low-stress operation of LED light sources may be missed. We present an efficiency-decay model approach, where all lumen maintenance data can be used to provide an alternative estimate of the decay rate constant. The approach considers a combined model wherein one part describes an initial “break-in” period and another part describes the decay in lumen maintenance. During the break-in period, several mechanisms within the LED can act to produce a small (typically < 10%) increase in luminous flux. The effect of the break-in period and its longevity is more likely to be present at low-ambient temperatures and currents, where the discrepancy between a standard TM-21 approach and our proposed model is the largest. For high temperatures and currents, the difference between the estimates becomes nonsubstantial. Our approach makes use of all the collected data and avoids producing unrealistic estimates of the decay coefficient.

A number of crowd accidents in last decades have attracted the interests of scientists in the study of self-organized behavior of crowd under extreme conditions. The faster-is-slower effect is one of the most referenced behaviors in pedestrian dynamics. However, this behavior has not been experimentally verified yet. A series of experiments with mice under panic were conducted in a bi-dimensional space. The mice were trained to be familiar with the way of escape. A varying number of joss sticks were used to produce different levels of stimulus to drive the mice to escape. The evacuation process was video-recorded for further analysis. The experiment found that the escape times significantly increased with the levels of stimulus due to the stronger competition of selfish mice in panic condition. The faster-is-slower effect was experimentally verified. The probability distributions of time intervals showed a power law and the burst sizes exhibited an exponential behavior.

This paper is concerned with the reaction–advection–diffusion equations with bistable nonlinearity in periodic media. Assume that the equation has three equilibria: an unstable equilibrium θ and two stable equilibria 0 and 1. It is known that there exist different pulsating fronts connecting any two of those three equilibria. In this paper we first study the exponential behavior of the fronts when they approach their stable limiting states. Then, we establish three different types of pulsating entire solutions for the equation. To establish the existence of entire solutions, we consider combinations of any two of those different pulsating fronts and construct appropriate sub- and supersolutions.

Představujeme měření optických vlastností krystalického PbIn6Te10. Vzorky se pěstují ve formě hranolů o velikosti _5 _ 3 _ 0,3 mm3. Absorpční koeficient (HN) ukazuje na exponenciální chování s energií v energetickém rozsahu 0.82-0.99 eV následovaným náhlým zvýšením vstřebávání z 1:07 na 1:13 eV. We present measurements of the optical properties of crystalline PbIn6Te10. The samples are grown in the form of parallelepipeds of size _5 _ 3 _ 0.3 mm3. The absorption coefficient a(hn) shows an exponential behavior with energy in the energy range 0.82–0.99 eV followed by an abrupt increase in the absorption from 1.07–1.13 eV.

Magnetic skyrmions are topologically protected spin textures with promising prospects for applications in data storage. They can form a lattice state due to competing magnetic interactions and are commonly found in a small region of the temperature—magnetic field phase diagram. Recent work has demonstrated that these magnetic quasi-particles fluctuate at the μeV energy scale. Here, we use a coherent x-ray correlation method at an x-ray free-electron laser to investigate these fluctuations in a magnetic phase coexistence region near a first-order transition boundary where fluctuations are not expected to play a major role. Surprisingly, we find that the relaxation of the intermediate scattering function at this transition differs significantly compared to that deep in the skyrmion lattice phase. The observation of a compressed exponential behavior suggests solid-like dynamics, often associated with jamming. We assign this behavior to disorder and the phase coexistence observed in a narrow field-window near the transition, which can cause fluctuations that lead to glassy behavior.

The body-centered cubic (BCC) Ti15Zr15Nb35Ta35 high-entropy alloy showed superconducting behavior at around 8 K. The electronic specific heat coefficient γ and the lattice specific heat coefficient β were determined to be γ = 9.3 ± 0.1 mJ/mol K2 and β = 0.28 ± 0.01 mJ/mol K4, respectively. It was found that the electronic specific heat Ces does follow the exponential behavior of the Bardeen-Cooper-Schrieffer (BCS) theory. Nevertheless, the specific heat jump (ΔC/γTc) at the superconducting transition temperature which was determined to be 1.71 deviates appreciably from that for a weak electron-phonon coupling BCS superconductor. Within the framework of the strong-coupled theory, our analysis suggests that theTi15Zr15Nb35Ta35 HEA is an intermediate electron-phonon coupled BCS-type superconductor.

We determine the asymptotic behavior of the tails of the steady state velocity distribution of a homogeneously driven granular gas comprising of particles having a scalar velocity. A pair of particles undergo binary inelastic collisions at a rate that is proportional to a power of their relative velocity. At constant rate, each particle is driven by multiplying its velocity by a factor $-r_w$ and adding a stochastic noise. When $r_w, 27 pages, 5 figures. J Stat Phys (2019)

In this work we present an agent-based computational model to study the spreading of the tuberculosis (TB) disease on age-structured populations. The model proposed is a merge of two previous models: an agent-based computational model for the spreading of tuberculosis and a bit-string model for biological aging. The combination of TB with the population aging, reproduces the coexistence of health states, as seen in real populations. In addition, the universal exponential behavior of mortalities curves is still preserved. Finally, the population distribution as function of age shows the prevalence of TB mostly in elders, for high efficacy treatments.

In this work, we study the existence, uniqueness, and exponential asymptotic behavior of mild solutions to stochastic integrodifferential delay evolution equations. We assume that the non-delay part generates a C0-semigroup.

In the present study, investigation of extracorporeal shock wave lithotripsy in Zakho City for breakdown kidney and ureteral stones has been carried out. The data were collected from the center of breakdown kidney stones in Zakho hospital. A total of 34 patients (25 male and 9 female) of ages ranged from 20 - 60 years were treated with ESWL. The patient harboring 24 renal stones and 10 ureteral stones of size ranged from 7 to 23 mm of almost patients are 8 mm and composed of calcium oxalate. The study has been conducted taking in to consideration the parameters (type, sizes, composition and location of stone as well as region and ages of patients, also power, number of shock wave and session). The results show that the number of shock wave decreases nearly exponentially with the ages of patients for calcium oxalate stone of size 8 mm under constant power 4 watt while it tends to increase according to increasing stones size for the patients of ages 20 - 30 years. The size of calcium oxalate stones decreases nearly exponentially with the patients’ ages for workers in Zakho city. Also for same size 8 mm of (calcium, phosphate, and oxalate) stones and different regions of zakho city, the number of shock waves decreases according to increasing ages of patients. Contrary to that for certain size of stones 8 mm, the number of shock wave starts to increase from uric acid to maximum value for calcium oxalate stone for the adult patients of age’s 22 up to 30 years. However for elders ages 30 - 60 years and different regions, the size of renal and ureteric stones increases from the minimum value for calcium, phosphate, oxalate to maximum value for calcium oxalate stone only. Uric acid stone requires minimum power to break, while the calcium oxalate needs maximum power to fragment due to its hardness composition. Later number of session of shock wave required for crushing each stones size increases according to increasing its size while its variation due to enhancing patients ages for calcium oxalate of size 8 mm results in nearly a decreasing exponential behavior.

A fundamental issue in the dynamics of complex systems is the resilience of the network in response to targeted attacks. This paper explores the local dynamics of the network attack process by investigating the order of removal of the nodes that have maximal degree, and shows that this dynamic network response can be predicted from the graph's initial connectivity. We demonstrate numerically that the maximal degree M(τ) of the network at time step τ decays exponentially with τ via a topology-dependent exponent. Moreover, the order in which sites are removed can be approximated by considering the network's "hierarchy" function h, which measures for each node V_{i} how many of its initial nearest neighbors have lower degree versus those that have a higher one. Finally, we show that the exponents we identified for the attack dynamics are related to the exponential behavior of spreading activation dynamics. The results suggest that the function h, which has both local and global properties, is a novel nodal measurement for network dynamics and structure.