The emergence of an epidemic evokes the need to monitor its spread and assess and validate any mitigation measures enacted by governments and administrative bodies in real time. We present here a method based on previous models of relaxation in fractal structures to observe and quantify this spread and the response of affected populations and governing bodies, and apply it to COVID-19 as a case study. This method provides means to simultaneously track in real time quantities such as the mortality and the recovery rates as well as the number of new infections caused by an infected person. With sufficient data, this method enables thorough monitoring and assessment of an epidemic without ad-hoc assumptions regarding the evolution of the pandemic in the future.

The complex symbiotic relationship in the industrial symbiosis network (ISN) may cause new risks for firms. In view of this problem, previous studies mainly regard the ISN as a static system, without considering the adaptive behavior of firms. This paper establishes a risk propagation model of the ISN based on the change of firm state, proposes four kinds of reconnection strategies to model the adaptive behavior, and uses numerical simulation to investigate the effect of adaptive behavior on risk propagation. The results demonstrate that all the reconnection strategies play an inhibitory role in the risk propagation. Therein, the effectiveness of PP strategy is the best, followed by RR strategy, and DP (SP) strategy. In any case, the effect of reconnection strategies on risk propagation will improve with the increase of the disconnection probability and network resilience. Additionally, the more decentralized weight distribution will weaken the inhibition of adaptive behavior on risk propagation.

Identifying the source of information in a network plays a key role in controlling the impact of information. Herein, we study the problem of multiple source localization in the context of information propagation in social networks. We use the theory of the naming game to conduct observations. Moreover, we divide the observations into different sets based on the information provided by them and then estimate the source of each set. Finally, we combine the source of each observation set to obtain all the estimated information sources. The proposed method can locate sources without knowing the number of information sources. Simulations on four real data sets are provided to verify the performance of our method.

In this paper we consider dipole-mediated correlations between DNA and enzymes in the context of their water environment. Such correlations emerge from electric dipole-dipole interactions between aromatic ring structures in DNA and in enzymes. We show that there are matching collective modes between DNA and enzyme dipole fields, and that a dynamic time-averaged polarization vanishes in the water dipole field only if either DNA, enzyme, or both are absent from the sample. This persistent field may serve as the electromagnetic image that, in popular colloquialisms about DNA biochemistry, allows enzymes to "scan" or "read" the double helix. Topologically nontrivial configurations in the coherent ground state requiring clamplike enzyme behavior on the DNA may stem, ultimately, from spontaneously broken gauge symmetries.

The influence of the magnetization configuration on Kondo effect in magnetic tunnel junction is investigated. In the parallel configuration, an additional resistance contribution (*) below 40 K exhibits a logarithmic temperature dependence, indicating the presence of Kondo effect. However, in the anti-parallel configuration, the Kondo-effect-associated spin-flip scattering has a nontrivial contribution to the tunneling current, which compensates the reduction of the current directly caused by Kondo scattering, making * disappear. These results indicate that suppression and restoration of Kondo effect can be experimentally achieved by altering the magnetization configuration, enhancing our understanding of the role of Kondo effect in spin-dependent transport.

A Green's function (GF) method is developed for interpreting scanning probe microscopy (SPM) measurements on new two-dimensional (2D) materials. GFs for the Laplace/Poisson equations are calculated by using a virtual source method for two separate cases of a finite material containing a rectangular defect and a hexagonal defect. The prescribed boundary values are reproduced almost exactly by the calculated GFs. It is suggested that the GF is not just a mathematical artefact but a basic physical characteristic of material systems, which can be measured directly by SPM for 2D solids. This should make SPM an even more powerful technique for characterization of 2D materials.

The problem of finding a better immunization strategy for controlling the spreading of the epidemic with limited resources has attracted much attention since its great theoretical significance and wide application. In this letter, we propose a novel and successful targeted immunization strategy based on percolation transition. Our strategy repeatedly looks for the critical nodes for immunizing. The critical node, which leads to the emergence of the giant connected component as the degree threshold increases, is determined when the maximal second-largest connected component disappears. To test the effectiveness of the proposed method, we conduct the experiments on several artificial networks and real-world networks. The results show that the proposed method outperforms the degree centrality strategy, the betweenness centrality strategy and the adaptive degree centrality strategy with 18% to 50% fewer immunized nodes for same amount of immunization.

When a quantum particle traverses a rectangular potential created by a quantum field both photon exchange and entanglement between particle and field take place. We present the full analytic solution of the Schrödinger equation of the composite particle-field system allowing investigation of these phenomena in detail and comparison to the results of a classical field treatment. Besides entanglement formation, remarkable differences also appear with respect to the symmetry between energy emission and absorption, resonance effects and if the field initially occupies the vacuum state.

We show that a reduced form of the structural requirements for deterministic hidden variables used in Bell-Kochen-Specker theorems is already sufficient for the no-go results. Those requirements are captured by the following principle: an observable takes a spectral value if and only if the spectral projector associated with takes the value 1. We show that the "only if" part of this condition suffices. The proof identifies an important structural feature behind the no-go results; namely, if one projector is assigned the value 1 in any resolution of the identity, then t one is.

We begin by giving correct expressions for the short-time action following the work Makri-Miller. We use these estimates to derive an accurate expression modulo [Formula: see text] for the quantum propagator and we show that the quantum potential is negligible modulo [Formula: see text] for a point source, thus justifying an unfortunately largely ignored observation of Holland made twenty years ago. We finally prove that this implies that the quantum motion is classical for very short times.

We study the weak values of a quantum observable from the point of view of the Wigner formalism. The main actor here is the cross-Wigner transform of two functions, which is in disguise the cross-ambiguity function familiar from radar theory and time-frequency analysis. It allows us to express weak values using a complex probability distribution. We suggest that our approach seems to confirm that the weak value of an observable is, as conjectured by several authors, due to the interference of two wavefunctions, one coming from the past, and the other from the future.

A simple approximation within the framework of the hybrid methods for the calculation of the electronic structure of solids is presented. By considering only the diagonal elements of the matrix of the perturbation operator (Hartree-Fock exchange minus semilocal exchange) calculated in the basis of the semilocal orbitals, the computational time is drastically reduced, while keeping very well in most studied cases the accuracy of the results obtained with hybrid functionals when applied without any approximations.

So far fluid mechanical Nambu brackets have mainly been given on an intuitive basis. Alternatively an algorithmic construction of such a bracket for the two-dimensional vorticity equation is presented here. Starting from the Lie-Poisson form and its algebraic properties it is shown how the Nambu representation can be explicitly constructed as the continuum limit from the structure preserving Zeitlin discretization.

In this Letter, we apply the predictive control strategy to suppress the propagation of diseases or viruses in small-world network. The stability of small-world spreading model with predictive controller is investigated. The sufficient and necessary stability condition is given, which is closely related to the controller parameters and small-world rewiring probability . Our simulations discover a phenomenon that, with the fixed predictive controller parameters, the spreading dynamics become more and more stable when decreases from a larger value to a smaller one, and the suitable controller parameters can effectively suppress the spreading behaviors even when varies within the whole spectrum, and the unsuitable controller parameters can lead to oscillation when lies within a certain range.

We consider the influence of a terahertz field on the breathing dynamics of double-stranded DNA. We model the spontaneous formation of spatially localized openings of a damped and driven DNA chain, and find that linear instabilities lead to dynamic dimerization, while true local strand separations require a threshold amplitude mechanism. Based on our results we argue that a specific terahertz radiation exposure may significantly affect the natural dynamics of DNA, and thereby influence intricate molecular processes involved in gene expression and DNA replication.

Statistical physics and information theory is applied to the clinical chemistry measurements present in a patient database containing 2.5 million patients' data over a 20-year period. Despite the seemingly naive approach of aggregating all patients over all times (with respect to particular clinical chemistry measurements), both a diurnal signal in the decay of the time-delayed mutual information and the presence of two sub-populations with differing health are detected. This provides a proof in principle that the highly fragmented data in electronic health records has potential for being useful in defining disease and human phenotypes.

The time course of an epidemic can be modeled using the differential equations that describe the spread of disease and by dividing people into "patches" of different sizes with the migration of people between these patches. We used these multi-patch, flux-based models to determine how the time course of infected and susceptible populations depends on the disease parameters, the geometry of the migrations between the patches, and the addition of infected people into a patch. We found that there are significantly longer lived transients and additional "ancillary" epidemics when the reproductive rate is closer to 1, as would be typical of SARS (Severe Acute Respiratory Syndrome) and bird flu, than when is closer to 10, as would be typical of measles. In addition we show, both analytical and numerical, how the time delay between the injection of infected people into a patch and the corresponding initial epidemic that it produces depends on .

The upper limit of momentum transfer by a proton to K-shell electrons is calculated in a restricted three-body classical model. The model shows that the infinite upper limit used in practice, is generally good except for low energy protons passing through an extremely rarefied gas.

A resonant transition amplitude, valid to arbitrary order, is derived through the use of a complex energy T-matrix. A feature of this amplitude is its generality and simplicity making it useful for widespread applications in resonance theory.

Ultrasonic velocity measurements in KTaO between 2° and 300°K are reported. No evidence for a phase transition was observed.