Search

Thermal activation of a particle from a deep potential trap follows the Arrhenius law. Recently, this result has been generalized for interacting diffusive particles in the trap, revealing two universality classes—the Arrhenius class and the excluded volume class. The result was demonstrated with the aid of numerical analysis. Here, we present a perturbative hydrodynamic approach to analytically validate the existence and range of validity for the two universality classes. [ABSTRACT FROM AUTHOR]

"Gating" is a widely observed phenomenon in biochemistry that describes the transition between the activated (or open) and deactivated (or closed) states of an ion-channel, which makes transport through that channel highly selective. In general, gating is a mechanism that imposes an additional restriction on a transport, as the process ends only when the "gate" is open and continues otherwise. When diffusion occurs in the presence of a constant bias to a gated target, i.e., to a target that switches between an open and a closed state, the dynamics essentially slow down compared to ungated drift-diffusion, resulting in an increase in the mean completion time, ⟨TG⟩ > ⟨T⟩, where T denotes the random time of transport and G indicates gating. In this work, we utilize stochastic resetting as an external protocol to counterbalance the delay due to gating. We consider a particle in the positive semi-infinite space that undergoes drift-diffusion in the presence of a stochastically gated target at the origin and is moreover subjected to rate-limiting resetting dynamics. Calculating the minimal mean completion time ⟨ T r ⋆ G ⟩ rendered by an optimal resetting rate r⋆ for this exactly solvable system, we construct a phase diagram that owns three distinct phases: (i) where resetting can make gated drift-diffusion faster even compared to the original ungated process, ⟨ T r ⋆ G ⟩ < ⟨ T ⟩ < ⟨ T G ⟩ , (ii) where resetting still expedites gated drift-diffusion but not beyond the original ungated process, ⟨ T ⟩ ≤ ⟨ T r ⋆ G ⟩ < ⟨ T G ⟩ , and (iii) where resetting fails to expedite gated drift-diffusion, ⟨ T ⟩ < ⟨ T G ⟩ ≤ ⟨ T r ⋆ G ⟩. We also highlight various non-trivial behaviors of the completion time as the resetting rate, gating parameters, and geometry of the set-up are carefully ramified. Gated drift-diffusion aptly models various stochastic processes such as chemical reactions that exclusively take place in certain activated states of the reactants. Our work predicts the conditions under which stochastic resetting can act as a useful strategy to enhance the rate of such processes without compromising their selectivity. [ABSTRACT FROM AUTHOR]

This study demonstrates an integrated approach using a seismic-coloured inversion to derive the hydrocarbon potential of a field in the Upper Assam basin. The well-log analysis indicated the presence of hydrocarbon in the form of gas, oil, and water in sandstones with thin streaks of limestone and shale layers. The Acoustic Impedance (AI) model was generated from post-stack seismic data using a coloured inversion. Shale volume (Vshale), density, porosity and water saturation are the petrophysical parameters spatially populated using a multilayered feed-forward neural network on the inversion-based AI model. The estimated range of model-derived parameters varies as Velocity: 2136–5034 m/s, Vshale: 0–48%, Density: 2.14–2.72 gm/cc, Porosity: 6–29%, Water saturation: 9–28%, and demonstrates a reasonable correlation to well-log data. Seismic attribute for thin-fault likelihood was used to interpret the major faults. From the combined analysis based on interpreted faults and modelled parameters, the northwestern part of the study area displays a thick hydrocarbon-bearing zone (due to increasing thickness and reservoir quality). This interpretation is based on the consideration that faults are open. Thus, assuming continuity in the sequence, this northwestern region can be considered as one of the promising candidates for further exploration. [ABSTRACT FROM AUTHOR]

We present a scheme for producing tunable active dynamics in a self-propelled robotic device. The robot moves using the differential drive mechanism where two wheels can vary their instantaneous velocities independently. These velocities are calculated by equating robot's equations of motion in two dimensions with well-established active particle models and encoded into the robot's microcontroller. We demonstrate that the robot can depict active Brownian, run and tumble, and Brownian dynamics with a wide range of parameters. The resulting motion analyzed using particle tracking shows excellent agreement with the theoretically predicted trajectories. Later, we show that its motion can be switched between different dynamics using light intensity as an external parameter. Intriguingly, we demonstrate that the robot can efficiently navigate through many obstacles by performing stochastic reorientations driven by the gradient in light intensity towards a desired location, namely the target. This work opens an avenue for designing tunable active systems with the potential of revealing the physics of active matter and its application for bio- and nature-inspired robotics. [ABSTRACT FROM AUTHOR]

Triboelectrification necessitates a frictional interaction between two materials, and their contact electrification is characteristically based on the polarity variance in the triboelectric series. Utilizing this fundamental advantage of the triboelectric phenomenon, different materials can be identified according to their contact electrification capability. Herein, an in‐depth analysis of the amino acids present in the stratum corneum of human skin is performed and these are quantified regarding triboelectric polarization. The principal focus of this study lies in analyzing and identifying the amino acids present in copious amounts in the stratum corneum to explain their positive behavior during the contact electrification process. Thus, an augmented triboelectric series of amino acids with quantified triboelectric charging polarity by scrutinizing the transfer charge, work function, and atomic percentage is presented. Furthermore, the chirality of aspartic acid as it is most susceptible to racemization with clear consequences on the human skin is detected. The study is expected to accelerate research exploiting triboelectrification and provide valuable information on the surface properties and biological activities of these important biomolecules. [ABSTRACT FROM AUTHOR]

Estimation of reservoir properties from seismic data suffers from non-unique solutions. A workflow based on the numerical reformulation of a laboratory-based rock physics model may reduce the non-uniqueness. This study attempts to integrate seismic and well log data of relatively unexplored parts of Upper Assam (UA) basin using inversion driven by laboratory based rock physics model. The laboratory-based rock physics model was developed based on experimental measurements conducted on rock cores from Tipam and Barail formations of the basin. Seismic inversion analysis was performed in OpendTect, an open-source software on post-stack seismic data to derive the acoustic impedance (AI) using coloured inversion. A multilayered feed-forward neural network was developed to spatially populate different petrophysical properties. Laboratory-based correlations between AI, density, porosity were utilised for the AI model from which velocity was computed using multivariate rock physics equation. This derived velocity value was transformed to AI and subsequently trained with well log to populate density (2.23-2.73 gm/cc) and porosity (7-28%) for the entire survey area. A reasonable to high correlation is obtained between bulk density and porosity derived by NN using well log and that derived by laboratory-based model (r = 0.78, 0.91 for Barail and 0.95, 0.94 for Sylhet formation). Thus, integrating datasets of different scale from seismic to core with well log data using neural network helps to derive more realistic models that helps in quantitative decision analysis. [ABSTRACT FROM AUTHOR]

We study the statistical properties of first-passage Brownian functionals (FPBFs) of an Ornstein–Uhlenbeck process in the presence of stochastic resetting. We consider a one dimensional set-up where the diffusing particle sets off from x 0 and resets to x R at a certain rate r. The particle diffuses in a harmonic potential (with strength k) which is centered around the origin. The center also serves as an absorbing boundary for the particle and we denote the first passage time (FPT) of the particle to the center as t f . In this set-up, we investigate the following functionals: (i) local time T l o c = ∫ 0 t f d τ δ (x − x R) i.e. the time a particle spends around x R until the first passage, (ii) occupation or residence time T r e s = ∫ 0 t f d τ θ (x − x R) i.e. the time a particle typically spends above x R until the first passage and (iii) the FPT t f to the origin. We employ the Feynman–Kac formalism for renewal process to derive the analytical expression for the first moment of all the three FPBFs mentioned above. In particular, we find that resetting can either prolong or shorten the mean residence and FPT depending on the system parameters. The transition between these two behaviors or phases can be characterized precisely in terms of optimal resetting rates, which interestingly undergo a continuous transition as we vary the trap stiffness k. We characterize this transition and identify the critical-parameter and -coefficient for both the cases. We also showcase other interesting interplay between the resetting rate and potential strength on the statistics of these observables. Our analytical results are in excellent agreement with the numerical simulations. [ABSTRACT FROM AUTHOR]

This paper investigates a mixed H 2 / H ∞ robust formation tracking control problem for linear multi-agent systems (MAS) in presence of disturbances and measurement noises in the agent model. An output based dynamic controller is proposed for each agent, which minimizes the mixed H 2 / H ∞ performance measure, and ensures formation tracking under directed network topology. With the help of the unified framework representation, the formation control problem is converted to the robust performance problem for an agent. Mixed sensitivity conditions are in the form of linear matrix inequalities (LMIs), and the solution leads to controller synthesis. Finally, the effectiveness of the proposed approach has been demonstrated through a numerical example in the MATLAB environment. [ABSTRACT FROM AUTHOR]

We examined the effects of the petrophysical and mineralogical variables on the acoustic properties of Upper Assam sandstones. All parameters were evaluated in the laboratory using recognized standard laboratory methods. Compressional wave velocity was measured in the laboratory using piezoelectric transducers of 54 kHz by using the ultrasonic-through transmission technique. Single parameter correlations among bulk density, porosity, permeability and mineralogy with compressional wave velocity showed that the compressional wave velocity correlated inversely with porosity, permeability and feldspar content and directly with bulk density and quartz content. For instance, a plug with a higher amount of feldspar content showed a corresponding decrease in compressional wave velocity. Similarly, higher quartz content showed a higher compressional wave velocity. Nevertheless, to depict a clear correlation among different parameters, a multiparameter analysis was performed. It was observed that the coefficient of determination improved from 0.596 to 0.899 when compressional wave velocity was modelled in terms of bulk density, porosity, quartz and feldspar content collectively, rather than when compressional wave velocity was modelled as a function of porosity alone. Hence, our study suggests that multiple parameters exhibit a coherent influence on compressional wave velocity. Therefore, a multivariate statistical approach involving petrophysical and mineralogical influences would be more realistic. Furthermore, major mineral fractions of sandstone rock type, that is quartz and feldspar fractions were varied for a range of porosity to determine the variations in compressional wave velocity for different saturation conditions. Capturing the fluctuations in compressional wave velocity within the geological constraints will aid in possible reservoir characterization away from the well-control or beyond the available data range. The integrated approach can result in more accurate and precise rock physics models that may help to infer key reservoir parameters. The developed models can be used in quantitative seismic interpretation for reservoir characterization and to identify prospective reservoirs. [ABSTRACT FROM AUTHOR]

The refractive index is a number that governs how light changes its direction of propagation as it enters one material medium from another. This phenomenon is known as refraction and the angles of incidence and refraction of light, referred to the normal to the interface of the two media at the point of incidence, are related by Snell's law. The refractive index (RI) depends on the color (or wavelength λ) of light. Tables of values of refractive indices for various media and wavelengths of light, with respect to vacuum, are readily available. The refractive index of a material can be measured by many methods, for example, by using a spectrometer in conjunction with a prism made of the experimental substance. An important class of methods of measuring RI involves the formation of interference patterns. Interferometric measurements are concerned with the study of separation between bright fringes (or dark fringes) resulting from the superposition of light waves, originating from a single source and propagating along paths of different optical lengths (refractive index multiplied by geometric path length). Researchers have exploited (nearly) monochromatic light from laser sources to enhance precision in measuring refractive index by applying interferometric techniques. [ABSTRACT FROM AUTHOR]

Multifunctional materials have gained huge attention owing to their great possibility in device applications. However, producing single-phase multifunctional materials, associated with various novel properties, has been proved to be a serious challenge. A simple yet effective way to overcome this barrier, is therefore of great importance. Here, we report the evolution of temperature- and magnetic field-dependent novel multifunctional phenomena in polycrystalline La 2- x Tb x CoMnO 6. Substitution of Tb in ferromagnetic La 2 CoMnO 6 , induces antiferromagnetic ordering through development of antisite disorder and antiphase boundaries, and results in a phase separation between ferromagnetic/antiferromagnetic layers. This originates the coexistence of conventional and inverse magnetocaloric effects in this system. The switching between them, with its tunability with temperature and magnetic field, suggests a huge potential of this compound. In addition, a clear correlation is established between the magnetocaloric switching and field-induced metamagnetic transitions. Furthermore, the discovery of tunable giant exchange bias (~1.8 kOe) at very low cooling field (500 Oe), a reasonable self-exchange bias (270 Oe), and a large negative magnetoresistance (~14%), makes this system enormously attractive for practical applications and fundamental research. The present study proposes a novel and effective route for successfully preparing essential multifunctional compounds to open a new pathway toward room-temperature applications. [ABSTRACT FROM AUTHOR]

The Mpemba effect is a fingerprint of the anomalous relaxation phenomenon wherein an initially hotter system equilibrates faster than an initially colder system when both are quenched to the same low temperature. Experiments on a single colloidal particle trapped in a carefully shaped double well potential have demonstrated this effect recently [A. Kumar and J. Bechhoefer, Nature 584, 64 (2020)]. In a similar vein, here, we consider a piece-wise linear double well potential that allows us to demonstrate the Mpemba effect using an exact analysis based on the spectral decomposition of the corresponding Fokker–Planck equation. We elucidate the role of the metastable states in the energy landscape as well as the initial population statistics of the particles in showcasing the Mpemba effect. Crucially, our findings indicate that neither the metastability nor the asymmetry in the potential is a necessary or a sufficient condition for the Mpemba effect to be observed. [ABSTRACT FROM AUTHOR]

Adsorption is the accumulation of a solute at an interface that is formed between a solution and an additional gas, liquid, or solid phase. The macroscopic theory of adsorption dates back more than a century and is now well-established. Yet, despite recent advancements, a detailed and self-contained theory of single-particle adsorption is still lacking. Here, we bridge this gap by developing a microscopic theory of adsorption kinetics, from which the macroscopic properties follow directly. One of our central achievements is the derivation of the microscopic version of the seminal Ward–Tordai relation, which connects the surface and subsurface adsorbate concentrations via a universal equation that holds for arbitrary adsorption dynamics. Furthermore, we present a microscopic interpretation of the Ward–Tordai relation that, in turn, allows us to generalize it to arbitrary dimension, geometry, and initial conditions. The power of our approach is showcased on a set of hitherto unsolved adsorption problems to which we present exact analytical solutions. The framework developed herein sheds fresh light on the fundamentals of adsorption kinetics, which opens new research avenues in surface science with applications to artificial and biological sensing and to the design of nano-scale devices. [ABSTRACT FROM AUTHOR]

The transport of particles through channels is of paramount importance in physics, chemistry, and surface science due to its broad real world applications. Much insight can be gained by observing the transition paths of a particle through a channel and collecting statistics on the lifetimes in the channel or the escape probabilities from the channel. In this paper, we consider the diffusive transport through a narrow conical channel of a Brownian particle subject to intermittent dynamics, namely, stochastic resetting. As such, resetting brings the particle back to a desired location from where it resumes its diffusive phase. To this end, we extend the Fick–Jacobs theory of channel-facilitated diffusive transport to resetting-induced transport. Exact expressions for the conditional mean first passage times, escape probabilities, and the total average lifetime in the channel are obtained, and their behavior as a function of the resetting rate is highlighted. It is shown that resetting can expedite the transport through the channel—rigorous constraints for such conditions are then illustrated. Furthermore, we observe that a carefully chosen resetting rate can render the average lifetime of the particle inside the channel minimal. Interestingly, the optimal rate undergoes continuous and discontinuous transitions as some relevant system parameters are varied. The validity of our one-dimensional analysis and the corresponding theoretical predictions is supported by three-dimensional Brownian dynamics simulations. We thus believe that resetting can be useful to facilitate particle transport across biological membranes—a phenomenon that can spearhead further theoretical and experimental studies. [ABSTRACT FROM AUTHOR]

How long does a trajectory take to reach a stable equilibrium point in the basin of attraction of a dynamical system? This is a question of quite general interest and has stimulated a lot of activities in dynamical and stochastic systems where the metric of this estimation is often known as the transient or first passage time. In nonlinear systems, one often experiences long transients due to their underlying dynamics. We apply resetting or restart, an emerging concept in statistical physics and stochastic process, to mitigate the detrimental effects of prolonged transients in deterministic dynamical systems. We show that resetting the intrinsic dynamics intermittently to a spatial control line that passes through the equilibrium point can dramatically expedite its completion, resulting in a huge reduction in mean transient time and fluctuations around it. Moreover, our study reveals the emergence of an optimal restart time that globally minimizes the mean transient time. We corroborate the results with detailed numerical studies on two canonical setups in deterministic dynamical systems, namely, the Stuart–Landau oscillator and the Lorenz system. The key features—expedition of transient time—are found to be very generic under different resetting strategies. Our analysis opens up a door to control the mean and fluctuations in transient time by unifying the original dynamics with an external stochastic or periodic timer and poses open questions on the optimal way to harness transients in dynamical systems. [ABSTRACT FROM AUTHOR]

A fully analytical surface potential and current–voltage model is presented for the first time for both lateral homojunction (HMJ) and heterojunction (HTJ) tunneling-field-effect transistors (TFETs) based on 2-D semiconducting channel materials. The dynamic gate-modulated electrostatic potential at the source/channel tunneling junction is suitably captured by solving a quasi-2-D Poisson’s equation in both source and channel. Subsequently, the band-to-band tunneling current is accurately derived starting from the Landauer’s equation by integrating over all possible carrier energies (or wave-vectors) over which tunneling is possible. The model employs Fermi–Dirac statistics in both the degenerate source and drain to compute the surface potential and net current, which yields more physical results than the commonly employed Boltzmann statistics. Its use in Landauer’s approach for evaluating the net ON-current leads to an analytical model of the TFET, which physically guarantees zero drain current at zero drain–source bias. Input and output characteristics for both HMJ and HTJ TFETs are computed and compared against rigorous nonequilibrium Green’s function (NEGF) simulations for different device parameters to prove the veracity of the model, and the match has been found to be excellent up to ultrashort channel length of 5 nm. [ABSTRACT FROM AUTHOR]

Optimal placement of Distributed Generation (DG) in the distribution network is a significant solution to resolve the power loss issue. Selection of the optimal locations and sizes of the DG is a practical problem and challenging job to achieve the minimum loss. In this work, the optimal location and appropriate size of the DGs have been found out to minimize the total active power loss of the distribution system with less penetration level of the DG considering of 24 hours duration. A modified search algorithm has been proposed in this paper which is capable to obtain the best solutions. Moreover, several reputed soft computing techniques have been applied to solve the problem and validate the optimal results. Technical aspects like energy losses have been minimized instead of power loss and practical factors like hourly basis solar output, wind generation and load variation have been considered to make this work more realistic. The solution techniques have been tested on the IEEE 33, IEEE 69 and 118 radial distribution test bus systems and results have been compared with recent literature. The quality of the results establishes the efficiency of the proposed modified algorithm to solve the optimal location and sizing problem with the effect of PV and wind power variation along with the variable load. [ABSTRACT FROM AUTHOR]

Extreme value statistics (EVS) concerns the study of the statistics of the maximum or the minimum of a set of random variables. This is an important problem for any time-series and has applications in climate, finance, sports, all the way to physics of disordered systems where one is interested in the statistics of the ground state energy. While the EVS of 'uncorrelated' variables are well understood, little is known for strongly correlated random variables. Only recently this subject has gained much importance both in statistical physics and in probability theory. In this review, we will first recall the classical EVS for uncorrelated variables and discuss the three universality classes of extreme value limiting distribution, known as the Gumbel, Fréchet and Weibull distribution. We then show that, for weakly correlated random variables with a finite correlation length/time, the limiting extreme value distribution can still be inferred from that of the uncorrelated variables using a renormalization group-like argument. Finally, we consider the most interesting examples of strongly correlated variables for which there are very few exact results for the EVS. We discuss few examples of such strongly correlated systems (such as the Brownian motion and the eigenvalues of a random matrix) where some analytical progress can be made. We also discuss other observables related to extremes, such as the density of near-extreme events, time at which an extreme value occurs, order and record statistics, etc. [ABSTRACT FROM AUTHOR]

Motion under stochastic resetting serves to model a myriad of processes in physics and beyond, but in most cases studied to date resetting to the origin was assumed to take zero time or a time decoupled from the spatial position at the resetting moment. However, in our world, getting from one place to another always takes time and places that are further away take more time to be reached. We thus set off to extend the theory of stochastic resetting such that it would account for this inherent spatio-temporal coupling. We consider a particle that starts at the origin and follows a certain law of stochastic motion until it is interrupted at some random time. The particle then returns to the origin via a prescribed protocol. We study this model and surprisingly discover that the shape of the steady-state distribution which governs the stochastic motion phase does not depend on the return protocol. This shape invariance then gives rise to a simple, and generic, recipe for the computation of the full steady state distribution. Several case studies are analyzed and a class of processes whose steady state is completely invariant with respect to the speed of return is highlighted. For processes in this class we recover the same steady-state obtained for resetting with instantaneous returns—irrespective of whether the actual return speed is high or low. Our work significantly extends previous results on motion with stochastic resetting and is expected to find various applications in statistical, chemical, and biological physics. [ABSTRACT FROM AUTHOR]

We study the statistical properties of a non-Markovian chiral run-and-tumble particle (CRTP) in two dimensions in continuous space and time. In our model, the possible orientations of the particle correspond to the four cardinal directions. The particle can reorient by turning left, right or reversing its direction of motion at different rates. We show how chirality manifests itself in the transport properties like the spatial moments of the marginal position distribution and the first-passage properties of a CRTP. Interestingly, we find that the chirality leads to enhanced diffusion and a looping tendency in the trajectory space. Our results show that chirality plays a pivotal role in the improvement of the search strategy — notably, there exists an optimal bias in tumbling that minimizes the mean search time. We determine an analytical expression for this optimal bias. Furthermore, we find that there exists a critical rate for the reversal of direction beyond which the optimal bias becomes constant. This behavioural drift is in stark contrast to that of the simple non-chiral particle. We believe that these key observations can play a crucial role in determining how living systems efficiently search under non-equilibrium conditions. [ABSTRACT FROM AUTHOR]

In this report, the effect of incorporation of hydrothermally prepared TiO2-Au nanocomposites in the photoanode of dye-sensitized solar cells (DSSCs), prepared from commercially available TiO2 nanoparticles, has been investigated. Electrophoretic deposition technique has been utilized for nanocomposite-doped photoanode preparation. The formation of hydrothermally prepared TiO2-Au nanocomposites has been confirmed by the X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), UV-Vis spectroscopy. The HRTEM images establish that the particle size of Au nanoparticles dispersed in TiO2 matrix varies from 2 to 45 nm. TiO2-Au photoelectrode has been characterized by XRD, field emission scanning electron microscopy, Raman spectroscopy and photoluminescence spectroscopy in order to confirm the successful preparation of plasmonic photoanodes. Measurement of current-voltage characteristics of the plasmonic dye-sensitized solar cells under the solar simulator illumination (100 mW/cm2, AM 1.5) shows enormous enhancement of power conversion efficiency. The PCE of plasmonic DSSCs is 10.1%, which is 134% greater than the DSSCs with pristine TiO2 photoanode of the same thickness. Electro-impedance spectroscopy reveals that the back electron transfer from the conduction band of Au-TiO2 photoanode to either dye or electrolyte has been significantly suppressed in the DSSC with plasmonic photoelectrode. [ABSTRACT FROM AUTHOR]

The outbreak of pandemics (e.g., severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 in 2019), influenza A viruses (H1N1 in 2009), etc.), and worldwide spike in the aging population have created unprecedented urgency for developing new drugs to improve disease treatment. As a result, extensive efforts have been made to design novel techniques for efficient drug monitoring and screening, which form the backbone of drug development. Compared to traditional techniques, microfluidics-based platforms have emerged as promising alternatives for high-throughput drug screening due to their inherent miniaturization characteristics, low sample consumption, integration, and compatibility with diverse analytical strategies. Moreover, the microfluidic-based models utilizing human cells to produce in-vitro biomimetics of the human body pave new ways to predict more accurate drug effects in humans. This review provides a comprehensive summary of different microfluidics-based drug sensing and screening strategies and briefly discusses their advantages. Most importantly, an in-depth outlook of the commonly used detection techniques integrated with microfluidic chips for highly sensitive drug screening is provided. Then, the influence of critical parameters such as sensing materials and microfluidic platform geometries on screening performance is summarized. This review also outlines the recent applications of microfluidic approaches for screening therapeutic and illicit drugs. Moreover, the current challenges and the future perspective of this research field is elaborately highlighted, which we believe will contribute immensely towards significant achievements in all aspects of drug development. • Comprehensive review of microfluidics-based drug sensing and screening. • Different microfluidics-based drug screening techniques are summarized. • The importance of different structural properties is summarized. • Applications in therapeutic and illicit drug screening are discussed. • Perspectives on future research directions are briefly illustrated. [ABSTRACT FROM AUTHOR]

In this paper, we present an analytical model for the drain current of a double-gate tunnel field-effect transistor (DGTFET), derived using the pseudo-2-D Poisson’s equation in order to obtain the surface potential in both the channel and the source regions. We have proposed a new model for the surface potential when the channel is under accumulation, and have analytically modeled source depletion as well. We have also proposed a modification in the existing model for the band-to-band tunneling, by taking into account the change in the carrier momentum vector during its transit from the source valence band to the channel conduction band. Another important contribution of our work is the prediction of zero drain current at zero drain bias, which is physically modeled for the first time. The negative conductance region for low gate bias is also modeled for the first time using an empirical formulation, without using any fitting parameter. Extensive TCAD simulations were performed in order to prove the veracity of our model with respect to drain bias, gate bias, substrate doping, and metal work function, and the match of our model results with the simulated data was found to be excellent. [ABSTRACT FROM PUBLISHER]

Traditional nearest neighbor classifiers based on usual distance functions (e.g., Euclidean distance) often suffer in high dimension low sample size (HDLSS) situations, where phenomena like concentration of pairwise distances, violation of cluster assumptions and presence of hubs often have adverse effects on their performance. In order to cope with such problems, instead of usual distance functions, in this article we use a dissimilarity measure based on average of absolute differences between inter-point distances. Our proposed nearest neighbor classifier uses concentration of pairwise distances to its advantage, and it usually yield better performance in high dimension when such concentration occurs. Under appropriate regularity conditions, we proved the optimality of the misclassification probability of the proposed classifier in HDLSS asymptotic regime, where the training sample size remains fixed, and the dimension grows to infinity. Usefulness of the proposed method has also been demonstrated using several simulated and benchmark data sets. [ABSTRACT FROM AUTHOR]

Background: The private sector is an important yet underregulated component of the TB treatment infrastructure in India. The Joint Effort for Elimination of Tuberculosis (Project JEET) aims to link private sector TB care with the constellation of social support mechanisms available through the Indian National TB Elimination Programme (NTEP), including the provision of free fixed-dose combination (FDCs) drugs to patients. This quasi-experimental study analysed routinely collected data to determine the impact of free drugs on patient follow-ups and treatment outcomes. Methods: We used data for private sector patients enrolled with Project JEET who were diagnosed with pulmonary and extrapulmonary TB between 1 and 2019 and 31 March 2020, and completed treatment by 31 December 2021. Propensity score matching was used to create a dataset to compare the number of follow-ups and proportion of successful treatment outcomes for patients on free drugs to a control group who paid out-of-pocket. 11,621 matched pairs were included in the analysis. Logistic regression and ordinary least squares regression models were used to estimate the impact of free drugs on number of follow-ups and treatment success, where latter is defined as treatment completion or cure. Results: After controlling for potential confounders, patients on free drugs received on average 2.522 (95% C.I.: 2.325 to 2.719) additional follow-ups compared to patients who paid out of pocket. This equates to a 25% mean and 32% median increase in follow-ups for patients availing free drugs. For treatment success, patients receiving free drugs had 45% higher odds of a successful treatment (Odds Ratio: 1.452, 95% C.I.: 1.288 to 1.637). Conclusions: Patients receiving free drugs were found to follow up with their treatment coordinator more frequently, in part likely to enable drug refilling, compared to patients who were paying out of pocket. These additional contacts would have offered opportunities to address concerns regarding side effects, provide additional treatment information, and connect with social support services, all of which subsequently contributed to patients' continual engagement with their treatment. This potentially represents the unmeasured effect of free drugs on continual social support, which translates into a higher odds of treatment success for patients. [ABSTRACT FROM AUTHOR]

The steady state of a Brownian particle diffusing in an arbitrary potential under the stochastic resetting mechanism has been studied. We show that there are different classes of nonequilibrium steady states depending on the nature of the potential. In the stable potential landscape, the system attains a well-defined steady state; however, the existence of the steady state for the unstable landscape is constrained. We have also investigated the transient properties of the propagator towards the steady state under the stochastic resetting mechanism. Finally, we have done numerical simulations to verify our analytical results. [ABSTRACT FROM AUTHOR]

We have considered the underdamped motion of a Brownian particle in the presence of a correlated external random force. The force is modeled by an Ornstein-Uhlenbeck process. We investigate the fluctuations of the work done by the external force on the Brownian particle in a given time interval in the steady state. We calculate the large deviation functions as well as the complete asymptotic form of the probability density function of the performed work. We also discuss the symmetry properties of the large deviation functions for this system. Finally we perform numerical simulations and they are in a very good agreement with the analytic results. [ABSTRACT FROM AUTHOR]

NbTe2 is a distorted monoclinic quasi-two-dimensional layered semimetal with superconductivity at 0.5 K. We report the investigation of the influence of Cu substitution on the superconductivity in NbTe2. Surprisingly, we found that a very small amount of Cu doing in Nb sites can greatly enhance the superconductivity of Nb1−xCuxTe2 single crystal samples. The superconducting transition temperature increases 6 times to 3 K for the optimal composition Nb0.95Cu0.05Te2, and then decreases for higher x; the superconducting transition temperature disappears when x = 0.1, which forms a dome-shaped superconducting phase diagram. [ABSTRACT FROM AUTHOR]

We consider a Brownian particle in a harmonic trap. The location of the trap is modulated according to an Omstein-Uhlenbeck process. We investigate the fluctuation of the work done by the modulated trap on the Brownian particle in a given time interval in the steady state. We compute the large deviation as well as the complete asymptotic form of the probability density function of the work done. The theoretical asymptotic forms of the probability density function are in very good agreement with the numerics. We also discuss the validity of the fluctuation theorem for this system. [ABSTRACT FROM AUTHOR]

Carbonates are known to have a heterogeneous, complicated pore structure, characterized by textural variations. This complex nature of carbonates makes it challenging to establish correlations to interpret petrophysical properties from acoustic properties. The present study focuses on investigating various parameters that influence carbonates by integrating parameters estimated from laboratory based measurements along with digital image analysis (DIA) technique, to capture the heterogeneity in pore architecture. A generalized rock physics model for carbonates of Bombay offshore basin has been developed based on compressional wave velocity (Vp) measured at laboratory conditions using ultrasonic measurement techniques. Our study maximizes the use of information obtained from the laboratory analysis that is usually constrained by accurate geological details. For this purpose, we measured Vp of carbonate core plugs using transducers of 54 kHz frequency by utilizing the through transmission technique. The parameters investigated at the laboratory include bulk density, porosity, permeability, mineral content, pore size and pore aspect ratio. Statistical analysis was performed using single as well as multiple parameter function. Mineral content was correlated with Vp and porosity. Bulk Density and porosity showed greater correlation with Vp as single parameter function while pore size showed poor correlation. A combination of bulk density, porosity and mode pore size was able to explain more than 83% of the deviation of Vp. It was observed that the predictability of Vp increases when it is modeled as a multi-parameter function of bulk density, porosity and pore size. The effectiveness of the velocity model improved when Vp was modeled as a function of these investigated parameters collectively rather than in isolation. Thus, an integrated study such as multi-regression analysis would help to present a more realistic picture that affect the relations between petrophysical, mineralogical and acoustic properties. Furthermore, while considering different saturation conditions, our study suggest that porosity and mineral composition have an effect on Vp, while effect of porosity is more prominent. We observed approximate 50% decrease in Vp values when porosity varied from 2 to 40% for different saturation conditions. Hence, the results potentially allow the interpretation of different petrophysical properties from acoustic data and thereby help in connecting geology and seismology. • This study investigates the controls on acoustic properties by petrophysical parameters. • We used laboratory based measurements and digital image techniques for the investigation. • We studied the statistical effect of pore geometry on compressional wave velocity. • A generalized rock physics model for carbonates is developed. • Our study evaluated the saturation effects in carbonates on compressional wave velocity. [ABSTRACT FROM AUTHOR]

Corrigendum to "Laboratory assessment on factors controlling the acoustic properties of carbonates: A case study from Bombay offshore" [J. Petrol. [Extracted from the article]

Aim: There is a paucity of data on cerebrospinal fluid (CSF) procalcitonin (PCT) to diagnose neonatal meningitis. We evaluated CSF PCT to diagnose bacterial meningitis among neonates with suspected sepsis. Methods: Neonates undergoing lumbar puncture (LP) as part of sepsis workup were included. Index Tests: CSF PCT, plasma PCT, CSF:plasma PCT ratio and CSF cytochemistry. Reference Standards: 'Definite meningitis' defined by positive CSF culture and/or gram stain and/or broad‐based primer 16S rDNA polymerase chain reaction. 'Definite or probable' meningitis is defined as definite meningitis or abnormal cytochemistry. Results: Of 216 eligible neonates, 18 had 'definite meningitis' and 37 'definite or probable meningitis'. Median (Q1, Q3) CSF PCT level was significantly higher in 'definite meningitis' compared to 'no definite meningitis' (0.429 (0.123, 1.300) vs. 0.181 (0.119, 0.286) ng/mL respectively, P = 0.028). Likewise, it was significantly higher in 'definite or probable meningitis' compared to no meningitis (0.245 (0.136, 0.675) vs. 0.170 (0.116, 0.28), P = 0.01). The area under the receiver operator characteristics curve of CSF PCT level for definite meningitis was 0.656 and for 'definite or probable meningitis' 0.635. Paired comparisons of area under the receiver operator characteristics curve of CSF PCT with the other index tests showed no significant differences. Based on a priori cut‐off of 0.2 ng/mL, CSF PCT level had a sensitivity (95% confidence interval) of 67% (50, 80), specificity 58% (54, 61), LR+ 1.6 (1.1, 2.0) and LR− 0.6 (0.3, 0.9). Conclusions: Higher values of CSF PCT are associated with neonatal bacterial meningitis. However, the diagnostic performance of CSF PCT is modest and not significantly different from standard tests. [ABSTRACT FROM AUTHOR]

Background: Post‐tuberculosis lung abnormality (PTLA) is the most common risk factor for chronic pulmonary aspergillosis (CPA), and 14%–25% of the subjects with PTLA develop CPA. The pathogenesis and the host immune response in subjects with PTLA who develop CPA need to be better understood. Methods: We prospectively compared the innate and adaptive immune responses mounted by patients of PTLA with or without CPA (controls). We studied the neutrophil oxidative burst (by dihydrorhodamine 123 test), classic (serum C3 and C4 levels) and alternative (mannose‐binding lectin [MBL] protein levels) complement pathway, serum immunoglobulins (IgG, IgM and IgA), B and T lymphocytes and their subsets in subjects with PTLA with or without CPA. Results: We included 111 subjects (58 CPA and 53 controls) in the current study. The mean ± SD age of the study population was 42.6 ± 15.7 years. The cases and controls were matched for age, gender distribution and body weight. Subjects with CPA had impaired neutrophil oxidative burst, lower memory T lymphocytes and impaired Th‐1 immune response (lower Th‐1 lymphocytes) than controls. We found no significant difference between the two groups in the serum complement levels, MBL levels, B‐cell subsets and other T lymphocyte subsets. Conclusion: Subjects with CPA secondary to PTLA have impaired neutrophil oxidative burst and a lower Th‐1 response than controls. [ABSTRACT FROM AUTHOR]

Cerebral vasospasm (CV) is a significant complication following aneurysmal subarachnoid hemorrhage (aSAH), and lacks a comprehensive molecular understanding. Given the temporal trajectory of intracranial aneurysm (IA) formation, its rupture, and development of CV, altered gene expression might be a molecular substrate that runs through these clinical events, influencing both disease inception and progression. Utilizing RNA-Seq, we analyzed tissue samples from ruptured IAs with and without vasospasm to identify the dysregulated genes. In addition, temporal gene expression analysis was conducted. We identified seven dysregulated genes in patients with ruptured IA with vasospasm when compared with those without vasospasm. We found 192 common genes when the samples of each clinical subset of patients with IA, that is, unruptured aneurysm, ruptured aneurysm without vasospasm, and ruptured aneurysm with vasospasm, were compared with control samples. Among these common genes, TNFSF13B, PLAUR, OSM, and LAMB3 displayed temporal expression (progressive increase) with the pathological progression of disease that is formation of aneurysm, its rupture, and consequently the development of vasospasm. We validated the temporal gene expression pattern of OSM at both the transcript and protein levels and OSM emerges as a crucial gene implicated in the pathological progression of disease. In addition, RSAD2 and ATP1A2 appear to be pivotal genes for CV development. To the best of our knowledge, this is the first study to compare the transcriptome of aneurysmal tissue samples of aSAH patients with and without CV. The findings collectively provide new insights on the molecular basis of IA and CV and new leads for translational research. [ABSTRACT FROM AUTHOR]

Summary: In general, the load demand of a standard microgrid system, changes on an hourly basis. Keeping in line with the rise and fall of this load demand curve, utilities fix different prices at different hours, which is termed as time of usage‐based electricity pricing. Elastic and inelastic are the two types of load that comprise the hourly demand of the microgrid system. Demand‐side management (DSM) shifts the elastic loads from peak load hours to those hours when the utility charges less thereby, restructuring the entire demand model‐based on demand‐price elasticity. Considering that the elastic loads contribute about 5% to 20% of the total load consumed during an hour, this paper implements a novel hybrid CSAJAYA algorithm to minimize the overall cost of a microgrid system considering DSM strategy. The various cost components taken into consideration are fuel cost, penalized emission cost, the cost of operation and maintenance, the cost of depreciation, etc. Numerical results depict that 30% to 40% decrement in overall generation cost was realized when DSM‐based energy management microgrid system was performed using the novel hybrid algorithm when compared to those available in the literature. Measures of central tendencies analysis claim the superiority of the proposed optimization algorithm. [ABSTRACT FROM AUTHOR]

We explore the role of non-ergodicity in the relationship between income inequality, the extent of concentration in the income distribution, and income mobility, the feasibility of an individual to change their position in the income rankings. For this purpose, we use the properties of an established model for income growth that includes 'resetting' as a stabilizing force to ensure stationary dynamics. We find that the dynamics of inequality is regime-dependent: it may range from a strictly non-ergodic state where this phenomenon has an increasing trend, up to a stable regime where inequality is steady and the system efficiently mimics ergodicity. Mobility measures, conversely, are always stable over time, but suggest that economies become less mobile in non-ergodic regimes. By fitting the model to empirical data for the income share of the top earners in the USA, we provide evidence that the income dynamics in this country is consistently in a regime in which non-ergodicity characterizes inequality and immobility. Our results can serve as a simple rationale for the observed real-world income dynamics and as such aid in addressing non-ergodicity in various empirical settings across the globe. This article is part of the theme issue 'Kinetic exchange models of societies and economies'. [ABSTRACT FROM AUTHOR]

Lead‐based halide perovskites APbX3 are likely to become competitive candidates in applications of photodetectors and X/γ‐ray detectors owing to their excellent optical and electrical characteristics, such as high and balanced carrier mobility, long carrier diffusion length, and adjustable bandgap. Based on this system, the article summarizes the performance parameters, such as responsivity, detectivity, external quantum efficiency, and response time of photodetector, and generalizes the research status of its application in near‐infrared light, visible light, and ultraviolet light photodetectors. In addition to that, it also summarizes the recent progress of X/γ‐ray detectors. What is more, the influence of radii of A‐site cations on the photoelectric performance are discussed. Finally, based on these summary and discussion, a research trend could be raised that more and more researchers tend to fabricate APbX3 perovskite with single‐crystalline thin‐film for high‐performance photodetectors in the future. It is proposed that if the A‐site ion is an organic group with a larger radius than the formamidinium (FA+), it may have better photoelectric properties than FAPbX3. Inorganic lead‐based perovskite single crystals with few defects, fast carrier mobility, and good stability are beneficial for attaining low dose rate and high‐energy resolution X/γ‐ray detectors. [ABSTRACT FROM AUTHOR]

We study the one-dimensional motion of a Brownian particle inside a confinement described by two reactive boundaries which can partially reflect or absorb the particle. Understanding the effects of such boundaries is important in physics, chemistry, and biology. We compute the probability density of the particle displacement exactly, from which we derive expressions for the survival probability and the mean absorption time as a function of the reactive coefficients. Furthermore, using the Feynman-Kac formalism, we investigate the local time profile, which is the fluctuating time spent by the particle at a given location, both till a fixed observation time and till the absorption time. Our analytical results are compared to numerical simulations, showing perfect agreement. [ABSTRACT FROM AUTHOR]

The canonical Evans-Majumdar model for diffusion with stochastic resetting to the origin assumes that resetting takes zero time: upon resetting the diffusing particle is teleported back to the origin to start its motion anew. However, in reality getting from one place to another takes a finite amount of time which must be accounted for as diffusion with resetting already serves as a model for a myriad of processes in physics and beyond. Here we consider a situation where upon resetting the diffusing particle returns to the origin at a finite (rather than infinite) speed. This creates a coupling between the particle's random position at the moment of resetting and its return time, and further gives rise to a nontrivial cross-talk between two separate phases of motion: the diffusive phase and the return phase. We show that each of these phases relaxes to the steady state in a unique manner; and while this could have also rendered the total relaxation dynamics extremely nontrivial, our analysis surprisingly reveals otherwise. Indeed, the time-dependent distribution describing the particle's position in our model is completely invariant to the speed of return. Thus, whether returns are slow or fast, we always recover the result originally obtained for diffusion with instantaneous returns to the origin. [ABSTRACT FROM AUTHOR]

Objective  Performing lumbar punctures (LP) in all clinically suspected neonatal sepsis, as per current recommendations, results in many "negative" LPs. LPs are not without their own risks. With the intention of minimizing unnecessary LPs among neonates, we aimed to identify a subgroup at extremely low risk of developing possible meningitis so that an LP could be safely avoided in it. Study Design  This was a prospective, observational, and cross-sectional study in a level III neonatal unit. We included 300 episodes, in which LP was performed for suspected sepsis. We recorded a comprehensive set of clinico-demographic variables, laboratory parameters, sickness score, organ dysfunction score, and organ localization and studied association of these factors with "definite (culture positive) or possible meningitis." "Possible" meningitis was defined with liberal criteria, intending not to miss any meningitis. A subgroup without a single factor associated with "definite or possible meningitis" was analyzed for incidence of meningitis. Results  There were 121 episodes of "definite or possible meningitis" among 300 episodes of sepsis. On unadjusted analysis, apnea, irritability, high-pitched cry, seizures, neutrophilia, high C-reactive protein (CRP), score for acute neonatal physiology and perinatal extension II (SNAPPE-II), urine output, and leukomalacia were associated with "definite or possible" meningitis (p  < 0.05). On multivariate analysis, no apneas, no neutrophilia, and normal CRP were independently associated with "no definite or possible meningitis." Nevertheless, the subgroup that had a combination of no apneas, no neutrophilia, and normal CRP (n  = 118) had a 29% probability of "definite or possible meningitis." Conclusion  The lowest risk subgroup had a 29% chance of having "definite or possible" meningitis. There is no subgroup that we could identify among neonates with suspected sepsis, in which it is safe to avoid an LP. Key Points LP are performed in all cases of late onset neonatal sepsis. Previous authors unsuccessfully tried to identify high-risk groups for performing LP. We were unable to identify an extremely low-risk group in which LP could be safely avoided. [ABSTRACT FROM AUTHOR]

Background: Mycobacterium w (Mw), an immunomodulator, resulted in better clinical status in severe coronavirus infectious disease 19 (COVID-19) but no survival benefit in a previous study. Herein, we investigate whether Mw could improve clinical outcomes and survival in COVID-19. Materials and Methods: In a multicentric, randomized, double-blind, parallel-group, placebo-controlled trial, we randomized hospitalized subjects with severe COVID-19 to receive either 0.3 mL/day of Mw intradermally or a matching placebo for three consecutive days. The primary outcome was 28-day mortality. The co-primary outcome was the distribution of clinical status assessed on a seven-point ordinal scale ranging from discharged (category 1) to death (category 7) on study days 14, 21, and 28. The key secondary outcomes were the change in sequential organ failure assessment (SOFA) score on days 7 and 14 compared to the baseline, treatment-emergent adverse events, and others. Results: We included 273 subjects (136 Mw, 137 placebo). The use of Mw did not improve 28-day survival (Mw vs. placebo, 18 [13.2%] vs. 12 [8.8%], P = 0.259) or the clinical status on days 14 (odds ratio [OR], 1.33; 95% confidence intervals [CI], 0.79-2.3), 21 (OR, 1.49; 95% CI, 0.83-2.7) or 28 (OR, 1.49; 95% CI, 0.79-2.8) between the two study arms. There was no difference in the delta SOFA score or other secondary outcomes between the two groups. We observed higher injection site reactions with Mw. Conclusion: Mw did not reduce 28-day mortality or improve clinical status on days 14, 21 and 28 compared to placebo in patients with severe COVID-19. [ABSTRACT FROM AUTHOR]

Synchronization is one of the emerging collective phenomena in interacting particle systems. Its ubiquitous presence in nature, science, and technology has fascinated the scientific community over the decades. Moreover, a great deal of research has been, and is still being, devoted to understand various physical aspects of the subject. In particular, the study of interacting active particles has led to exotic phase transitions in such systems which have opened up a new research front-line. Motivated by this line of work, in this paper, we study the directional synchrony among self-propelled particles. These particles move inside a bounded region, and crucially their directions are also coupled with spatial degrees of freedom. We assume that the directional coupling between two particles is influenced by the relative spatial distance which changes over time. Furthermore, the nature of the influence is considered to be both short and long-ranged. We explore the phase transition scenario in both the cases and propose an approximation technique which enables us to analytically find the critical transition point. The results are further supported with numerical simulations. Our results have potential importance in the study of active systems like bird flocks, fish schools, and swarming robots where spatial influence plays a pertinent role. [ABSTRACT FROM AUTHOR]