Numerical modeling of cracking pattern's influence on the dynamic response of thickened tailings disposals: a periodic approach

Copper production is an essential component of the Chilean economy. During the extraction process of copper, large quantities of waste materials（tailings） are produced, which are typically stored in large tailing ponds. Thickened Tailings Disposal（TTD） is an alternative to conventional tailings ponds. In TTD, a considerable amount of water is extracted from the tailings before their deposition. Once a thickened tailings layer is deposited, it loses water and it shrinks, forming a relatively regular structure of tailings blocks with vertical cracks in between, which are then filled up with ＂fresh＂ tailings once the new upper layer is deposited. The dynamic response of a representative column of this complex structure made out of tailings blocks with softer material in between was analyzed using a periodic half-space finite element model. The tailings＇ behavior was modeled using an elasto-plastic multi-yielding constitutive model, and Chilean earthquake records were used for the seismic analyses. Special attention was given to the liquefaction potential evaluation of TTD.

THREE- DIMENSIONAL PERIODICITY ANDTENFOLD ROTATIONAL SYMMETRY

Electron-diffraction pattern with 'tenfold rotational symmetry' of Al-Fe alloyphase is assumed to be produced by periodic structure. One 3D periodic structure is presentedbased on so-called C polyhedra. The structure can be used as atomic model to describethe Al-Fe alloy phase. The Fourier transform patterns of the model are in good agreementwith the corresponding electron-diffraction patterns. Several other models with' tenfold symmetry' Fourier transform patterns have briefly been mentioned.

Bifurcation and dynamics in double-delayed Chua circuits with periodic perturbation

Rank-1 attractors play a vital role in biological systems and the circuit systems.In this paper,we consider a periodically kicked Chua model with two delays in a circuit system.We first analyze the local stability of the equilibria of the Chua system and obtain the existence conditions of supercritical Hopf bifurcations.Then,we derive some explicit formulas about Hopf bifurcation,which could help us find the form of Hopf bifurcation and the stability of bifurcating period solutions through the Hassards method.Also,we show that rank-1 chaos occurs when the Chua model with two delays undergoes a supercritical Hopf bifurcation and encounters a periodic kick,which shows the effect of two delays on the circuit system.Finally,we illustrate the theoretical analysis by simulations and try to explain the mechanism of delay in our system.

Phase diagram,correlations,and quantum critical point in the periodic Anderson model

Periodic Anderson model is one of the most important models in the field of strongly correlated electrons. With the recent developed numerical method density matriX embedding theory, we study the ground state properties of the periodic Anderson model on a two-dimensional square lattice. We systematically investigate the phase diagram away from half filling. We find three different phases in this region, which are distinguished by the local moment and the spin-spin correlation functions. The phase transition between the two antiferromagnetic phases is of first order. It is the so-called Lifshitz transition accompanied by a reconstruction of the Fermi surface. As the filling is close to half filling, there is no difference between the two antiferromagnetic phases. From the results of the spin-spin correlation, we find that the Kondo singlet is formed even in the antiferromagnetic phase.

STOCHASTIC MODEL OF PERIODIC OPERATION PERFORMANCE FOR THE CONTINUOUS COUNTER－CURRENT ADSORPTION PROCESS

A stochastic model is developed to predict the peniodic operation performance ofthe continuous counter-current adsorption process. The model takes into account theeffects of random backmixing of particles, axial dispersion of liquid phase, liquid- film mass transfer, intraparticle diffusion and panticle shape, and can revealclearly the behavior of solid and liquid phase in adsorption process. The simulation results agree with the experimental data rather well.

Antiferromagnetism and Kondo screening on a honeycomb lattice

Magnetic adatoms in the honeycomb lattice have received tremendous attention due to the interplay between Ruderman-Kittel-Kasuya-Yosida interaction and Kondo coupling leading to very rich physics. Here we study the competition between the antiferromagnetism and Kondo screening of local moments by the conduction electrons on the honeycomb lattice using the determinant quantum Monte Carlo method. While changing the interband hybridization V, we systemat- ically investigate the antiferromagnetic-order state and the Kondo singlet state transition, which is characterized by the behavior of the local moment, antiferromagnetic structure factor, and the short range spin-spin correlation. The evolution of the single particle spectrum are also calculated as a function of hybridization V, we find that the system presents a small gap in the antiferromagnetic-order region and a large gap in the Kondo singlet region in the Fermi level. We also find that the localized and itinerant electrons coupling leads to the midgap states in the conduction band in the Fermi level at very small V. Moreover, the formation of antiferromagnetic order and Kondo singlet are studied as on-site interaction U or temperature T increasing, we have derived the phase diagrams at on-site interaction U （or temperature T） and hybridization V plane.

Interactional models for adults of two populations with maturation delays

This paper is concerned with interactional models for adults of two species delayed by their mature periods. The existence and local stability of equilibria are discussed thoroughly for competitive systems, cooperative systems and predator-prey systems, respectively. For systems with interaction of competition and cooperation, it is found that the two populations are uniformly persistent if the positive equilibrium is stable. For predator-prey interaction, however, some further conditions are needed to guarantee the persistence of the systems.

Laboratory Models for the Study of the Peri-implantation Period

The greatest risks to mammalian pregnancy occur during the peri-implantation period (passage through the uterotubal junction, blastulation, zona shedding, embryonic signaling and recognition, blastocyst attachment, postattachment events initiating placentation). Conventional markers and screening methods do not provide the means to clarify the relationship between exposure of a reproductively competent woman to a xenobiotic compound and the specific error in the functional expression of an embryogenetic process identified by impairment or deletion of that process. Laboratory models which provide the flexibility of in vitro culture methods and allow integration of cellular and molecular techniques have identified cell-specific, stage-specific markers that could focus on the mechanism of xenobiotic action. In vitro models have been used to define postattachment trophoblast cell differentiation. Trophoblast specific peptide hormones prove to be valid markers of established pregnancy. They provide no assessment of the risk to the embryo during the peri-implantation period. The relationship between developmental time of exposure and risk is discussed in terms of trophoblast differentiation.

Dynamics of a stochastic periodic SIRS model with time delay

Dynamical behaviors of a siocluustic periodic SIRS epidemic model with time delay are investigated.By constructing suitable Lyapunov functions and applying Ito's formula,the existence of the global positive solution and the property of stochastically ultimate boundedness of model(1.1)are proved.Moreover,the extinction and the persistence of the disease are established.The results are verified by numerical simulations.

Optimal Investment with Multiple Risky Assets for an Insurer with Modified Periodic Risk Process

This paper considers the optimal investment problem for an insurer in the sense of maximizing the adjustment coefficient of the risk process.The authors propose a modified periodic risk model in which the periodic risk process is perturbed by a standard Brownian motion.The insurer can invest in multiple risky assets and one risk-free asset and the correlations between the risky assets and the risk process are considered.Optimal strategy is obtained explicitly,which is a function of time and related to the risk process.The effects of market parameters on the optimal strategy are discussed and a numerical example is also given.

Invasion reproductive numbers for periodic epidemic models

There are many cases within epidemiology where infections compete to persist within a population.In studying models for such cases,one of the goals is to determine which infections can invade a population and persist when other infections are already resident within the population.Invasion reproductive numbers(IRN),which are tied to the stability of boundary endemic equilibria,can address this question.By reinterpreting resident infections epidemiologically,this study extends methods for finding IRNs to periodic systems,and presents some examples which illustrate the often complex computations required.Results identify conditions under which a simple time-average can be used to derive IRNs,and apply the methods to examine how seasonal fluctuations in influenza incidence facilitate the year-round persistence of bacterial respiratory infections.

MODELLING AND NUMERICAL SOLUTIONS OF A GAUGE PERIODIC TIME DEPENDENT GINZBURG-LANDAU MODEL FOR TYPE-Ⅱ SUPERCONDUCTORS

In this paper we seek the solutions of the time dependent Ginzburg-Landau model for type-Ⅱ superconductors such that the associated physical observables are spatially periodic with respect to some lattice whose basic lattice cell is not necessarily rectangular. After appropriately foring the gange, the model can be formulated as a system of nonlinear parabolic partial differential equations with quasi-periodic boundary conditions. We first give some results concerning the existence, uniqueness and regularity of solutions and then we propose a semiimplicit finite element scheme solving the system of nonlinear partial dmerential equations and show the optimal error estimates both in the L2 and energy norm.We also report on some numerical results at the end of the paper.

Discussion on the paper “Analyzing short time series data from periodically fluctuating rodent populations by threshold models: A nearestblock bootstrap approach”

This is a very attractive article. It combines fascinating new methodology with a most interesting dataset, and a highly motivating presentation. However, despite the many

Discussion on the paper “Analyzing short time series data from periodically fluctuating rodent populations by threshold models: A nearestblock bootstrap approach”

The authors are to be congratulated for an innovative paper in terms of both modelling methodology and subject matter significance. The analysis of short time series is known to be

Secular trends of asthma mortality in China and the United States from 1990 to 2019

Background:Asthma imposes a large healthcare burden in China and the United States(US).However,the trends of asthma mortality and the relative risk factors have not been comparatively analyzed between the countries.The aim of this study was to compare the mortality and risk factors between China and the US.Methods:The deaths,and mortality rates of asthma in China and the US during 1990–2019 were obtained from the Global Burden of Disease Study 2019.The age–period–cohort model was used to estimate these mortality rates based on a log-linear scale with additive age,period,and cohort effects.The population attributable fractions of risk factors for asthma were estimated.Results:In 1990–2019,the asthma mortality rate was higher in China than in the US.The crude and age-standardized asthma mortality rates trended downward in both China and the US from 1990 to 2019.The decline in mortality was more obvious in China.Mortality gap between the two countries was narrowing.A sex difference in asthma mortality was observed with higher mortality in males in China and females in the US.The age effects showed that mortality increased with age in adults older than 20 years,particularly in the elderly.Downward trends were generally observed in the period and cohort rate ratios in both countries,with China experiencing a more obvious decrease.Smoking and high body mass index(BMI)were the leading risk factors for asthma mortality in China and the US,respectively.Mortality attributable to occupational asthmagens and smoking decreased the most in China and the US,respectively.Conclusions:In 1990–2019,the asthma mortality rate was higher in China than in the US;however,the mortality gap has narrowed.Mortality increased with age in adults.The improvements in asthma death risk with period and birth cohort were more obvious in China than in the US.Smoking,high BMI,and aging are major health problems associated with asthma control.The role of occupational asthmagens in asthma mortality underscores the importance of management and prevention of occupational asthma.

THE INFLUENCE OF ARCTIC AND ANTARCTIC ICE ON SOUTHERN OSCILLATION

The analysis of the relationship between sea ice in Arctic and Antarctic, and the Southern Oscillation Index (SOI) variation on the temporal scale of month, season and year is made in this paper. The negative correlation between sea ice in Arctic and the SOI. and the positive correlation between sea ice in Antarctic and the SOI are found. The variation of sea ice in Antarctic Pacific seems to play an important role in the influence to atmosphere. Their nonlinear relationships present more strongly than the linear relationship between them. The relationship between sea ice in Arctic and Antarctic and the SOI in the early stage is investigated. Their variation shows periodic phenomena. The maximum correlation is used to build the model for forecasting the variation of the SOI on the condition of the sea ice in Arctic and Antarctic. The explained variance of the simulated series is greater than 0.90. There exists a 17-month period in the relationship between sea ice in Arctic and Antarctic and SOI. The existing of the common factor with larger scale is discussed in this paper.

COMBINING SINGULAR SPECTRUM ANALYSIS AND PAR(p) STRUCTURES TO MODEL WIND SPEED TIME SERIES

Singular spectrum analysis （SSA） is a technique that decomposes a time series into a set of components, such as, trend, harmonics, and residuals. Leaving out the residual components and adding up the others, the time series can be smoothed. This procedure has been used to model Brazilian electricity consumption and flow series. The PAR（p）, periodic autoregressive models, has been broadly used in modelling energy series in Brazil. This paper presents an approach of this decomposition method, by fitting the PAR（p）, considering its multivariate version known as multivariate SSA （MSSA）. The method was applied to a vector of two wind speed series recorded at two locations in the Brazilian Northeast region. The obtained results, when compared to the univariate decomposition of each series, were far superior, showing that the spatial correlation between the two series were considered by MSSA decomposition stage.

Cellular and Circuitry Bases of Autism:Lessons Learned from the Temporospatial Manipulation of Autism Genes in the Brain

Transgenic mice carrying mutations that cause Autism Spectrum Disorders（ASDs） continue to be valuable for determining the molecular underpinnings of the disorders. Recently, researchers have taken advantage of such models combined with Cre-lox P and similar systems to manipulate gene expression over space and time. Thus, a clearer picture is starting to emerge of the cell types, circuits, brain regions, and developmental time periods underlying ASDs. ASD-causing mutations have been restricted to or rescued speci？cally in excitatory or inhibitory neurons, different neurotransmitter systems, and cells speci？c to the forebrain or cerebellum. In addition,mutations have been induced or corrected in adult mice,providing some evidence for the plasticity and reversibility of core ASD symptoms. The limited availability of Cre lines that are highly speci？c to certain cell types or time periods provides a challenge to determining the cellular and circuitry bases of autism, but other technological advances may eventually overcome this obstacle.

The theoretical study of the efficiency of diffusion deposition of nanoaerosols in the extended range of the Peclet numbers

The efficiencies of the diffusion deposition of nanoaerosols for a single fiber for the models of aerosol filter and wire mesh screen are studied numerically in the extended range of the Peclet number Pe.The rectangular periodic cell model for fluid flow and convective-diffusive transport of small aerosol particles is used.Most of the previous theoretical and experimental studies of single fiber diffusion deposition efficiency were for the case of Pe>1.The array with uniform square or chess grid of fibers and of a row of circular cylindrical fibers are considered as the filter and wire mesh screen models.The flow and particles transport equations are solved numerically using the Boundary Element Method.The obtained numerical data are used to derive the approximate formulas for the deposition efficiency in the entire range of the Peclet number for the various porosities of the filter medium or distances between fibers in a wire mesh screen.The derived dependencies take into account nonlinearity of the deposition efficiency at the low Peclet numbers.The obtained analytical dependencies compare well with the numerical and experimental data.

Zero Temperature Numerical Studies of Multiband Lattice Models of Strongly Correlated Electrons

Relative to single-band models,multiband models of strongly interacting electron systems are of growing interest because of their wider range of novel phenomena and their closer match to the electronic structure of real materials.In this brief review we discuss the physics of three multiband models(the three-band Hubbard,the periodic Anderson,and the Falicov-Kimball models)that was obtained by numerical simulations at zero temperature.We first give heuristic descriptions of the three principal numerical methods(the Lanczos,the density matrix renormalization group,and the constrainedpath Monte Carlo methods).We then present generalized versions of the models and discuss the measurables most often associated with them.Finally,we summarize the results of their ground state numerical studies.While each model was developed to study specific phenomena,unexpected phenomena,usually of a subtle quantum mechanical nature,are often exhibited.Just as often,the predictions of the numerical simulations differ from those of mean-field theories.