Miracle-dz/UniFAR-FTUs huggingface dataset:
PERMANENT-TRANSITORY DECOMPOSITIONS UNDER WEAK EXOGENEITY

This note shows that the orthogonal shocks obtained by imposing a recursive structure on the contemporaneous impacts of the errors in a vector-error correction model (VECM) are related to the orthogonal permanent-transitory shocks in a Gonzalo and Ng (2001, Journal of Economic Dynamics and Control 25, 1527–1546) decomposition provided some of the variables in the system are weakly exogenous. Specifically, when there are as many weakly exogenous variables as common trends and the weakly exogenous variables are ordered first, the orthogonal shocks obtained directly from the VECM constitute a permanent-transitory decomposition, and the permanent shocks are identical to those in the Gonzalo and Ng decomposition.We are grateful to the co-editor Paolo Paruolo and an anonymous referee for useful comments, which have helped to improve the content and exposition of this note. Financial support from the Australian Research Council is gratefully acknowledged.
Nonlinear time series analysis of geomagnetic pulsations

Abstract. A detailed nonlinear time series analysis has been made of two daytime geomagnetic pulsation events being recorded at L'Aquila (Italy, L ≈ 1.6) and Niemegk (Germany, L ≈ 2.3). Grassberger and Procaccia algorithm has been used to investigate the dimensionality of physical processes. Surrogate data test and self affinity (fractal) test have been used to exclude coloured noise with power law spectra. Largest Lyapunow exponents have been estimated using the methods of Wolf et al. The problems of embedding, stability of estimations, spurious correlations and nonlinear noise reduction have also been discussed. The main conclusions of this work, which include some new results on the geomagnetic pulsations, are (1) that the April 26, 1991 event, represented by two observatory time series LAQ1 and NGK1 is probably due to incoherent waves; no finite correlation dimension was found in this case, and (2) that the June 18, 1991 event represented by observatory time series LAQ2 and NGK2, is due to low dimensional nonlinear dynamics, which include deterministic chaos with correlation dimension D2(NGK2) = 2.25 ± 0.05 and D2(NDK2) = 2.02 ± 0.03, and with positive Lyapunov exponents λ max (LAQ2) = 0.055 ± 0.003 bits/s and λ max (NGK2) = 0.052 ± 0.003 bits/s; the predictability time in both cases is ≈ 13 s.
The Seasonal Variation of the Tropical Circulation as Simulated by a Global Model of the Atmosphere

Abstract A mathematical model of the atmosphere with a seasonal variation of insulation and sea surface temperatures is integrated numerically with respect to time over three model years. The model has a global computational domain and a realistic distribution of mountains. It contains a highly idealized parameterization of convection, i.e., dry and moist convective adjustment. It is found that the model accurately simulates the seasonal variation of the location of the tropical rainbelt as well as that of the flow field associated with it. Over the continental regions of the model, the tropical rainbelt tends to form very close to the equator, whereas, in certain oceanic regions, it has a tendency to form away from the equator. Based upon a comparison of these results with those of another numerical experiment, it is concluded that this tendency is not due to an inherent characteristic of the rainbelt of the model to avoid the equator in oceanic regions, but rather it is due to the equatorial belt of low.
Connecting Levels of Representation: Emergent versus submergent perspective

Chemical phenomena can be described using three representation modes: macro, submicro, and symbolic. The way students use and connect these modes when solving conceptual problems was studied, using a think‐aloud interview protocol. The protocol was validated through interviews with six faculty members, and then applied to four graduate and six undergraduate chemistry students. We used a ‘levels of complexity’ framework to analyse responses: the macro and symbolic modes were considered system‐level representations, and the submicro mode a component‐level representation. We found that faculty members thought of system‐level properties as emerging from mechanistic interactions between particles on the component level—an emergent perspective. In many cases, the students either failed to connect the system and component levels, or thought of system‐level properties as guiding the behaviour of particles on the component level—a ‘submergent’ perspective. Some students used their familiarity with a symbolic equation describing the behaviour of a substance as the starting point of a thought process that leads them to impose mechanistically unwarrantable behaviour upon its particles. We concluded that a submergent perspective inhibits students from confronting their misconceptions regarding particle behaviour, and explains why students are often able to correctly solve algorithmic problems while failing to solve conceptual ones. It is suggested that the directionality of connecting particle behaviour to system‐level properties should be emphasized in teaching.
Moduli and periods of supersymmetric curves

Supersymmetric curves are the analogue of Riemann surfaces in super geometry. We establish some foundational results about complex Deligne-Mumford superstacks, and we then prove that the moduli superstack of supersymmetric curves is a smooth complex Deligne-Mumford superstack. We then show that the superstack of supersymmetric curves admits a coarse complex superspace, which, in this case, is just an ordinary complex space. In the second part of this paper we discuss the period map. We remark that the period domain is the moduli space of ordinary abelian varieties endowed with a symmetric theta divisor, and we then show that the differential of the period map is surjective. In other words, we prove that any first order deformation of a classical Jacobian is the Jacobian of a supersymmetric curve.
Classical and Relative Realizability

We show that every abstract Krivine structure in the sense of Streicher can be obtained, up to equivalence of the resulting tripos, from a filtered opca (A,A') and a subobject of 1 in the relative realizability topos RT(A',A); the topos is always a Booleanization of a closed subtopos of RT(A',A). We exhibit a range of non-localic Boolean subtoposes of the Kleene-Vesley topos.
A Fractional-Order Epidemic Model for Bovine Babesiosis Disease and Tick Populations

This paper shows that the epidemic model, previously proposed under ordinary differential equation theory, can be generalized to fractional order on a consistent framework of biological behavior. The domain set for the model in which all variables are restricted is established. Moreover, the existence and stability of equilibrium points are studied. We present the proof that endemic equilibrium point when reproduction number is locally asymptotically stable. This result is achieved using the linearization theorem for fractional differential equations. The global asymptotic stability of disease-free point, when , is also proven by comparison theory for fractional differential equations. The numeric simulations for different scenarios are carried out and data obtained are in good agreement with theoretical results, showing important insight about the use of the fractional coupled differential equations set to model babesiosis disease and tick populations.
INCREMENTAL CONSTITUTIVE LAW FOR SANDS AND CLAYS: SIMULATIONS OF MONOTONIC AND CYCLIC TESTS

An incremental formulation of constitutive laws is first presented and the fundamental notion of incremental non-linearity, necessary for the description of cyclic behaviour of soils, is emphasized. The incremental constitutive law for soils and its principal assumptions, which make it more general than the classical elastic-plastic models are detailed. The constitutive parameters of Hostun sand and Grundite clay are then given, as well as a comparison of theoretical results with experimental axisymmetrical and true triaxial measurements (Hostun sand tests at Grenoble and Grundite clay tests at Berkeley). Different cyclic behaviour simulations are presented, as well as an example of cyclic liquefaction of monterey loose sand. Finally, a simple shear test is simulated. (Author/TRRL)
Four-photon parametric mixing and interaction between filaments

Recently energy exchange between two filaments crossing at small angle and with power slightly above the critical for self-focusing Pcr was experimentally demonstrated. In this paper we present a model describing the process of this transfer through degenerate four-photon parametric mixing. Our model confirms the experimental results that the direction of energy exchange depends on the relative transverse velocity (incident angle), laser intensity and initial distance between the pulses (relative initial phase).
Ultimate limit and temperature dependency of light-emitting diode efficiency

We discuss the ultimate limit of performance of semiconductor light-emitting diodes (LEDs) and its dependence on temperature. It is known that in high quality semiconductor materials it is, in principle, possible to reach wall plug efficiencies exceeding unity, which allows electroluminescent cooling in addition of very high efficiency light emission. Our simulation results suggest a few fairly simple measures that may further improve the external quantum efficiency (EQE) of LEDs toward the electroluminescent cooling limit. These include reducing the current density, modifying the LED structure by making thicker active regions and barrier layers, and doping of the active material. Our calculations also indicate that, contrary to the present understanding, operating LEDs at relatively high temperatures of 400–600 K may, in fact, improve the performance.
The galactic globular cluster system

We explore correlations between various properties of Galactic globular clusters, using a database on 143 objects. Our goal is identify correlations and trends which can be used to test and constrain theoretical models of cluster formation and evolution. We use a set of 13 cluster parameters, 9 of which are independently measured. Several arguments suggest that the number of clusters still missing in the obscured regions of the Galaxy is of the order of 10, and thus the selection effects are probably not severe for our sample. Known clusters follow a power-law density distribution with a slope approximately -3.5 to -4, and an apparent core with a core radius approximately 1 kpc. Clusters show a large dynamical range in many of their properties, more so for the core parameters (which are presumably more affected by dynamical evolution) than for the half-light parameters. There are no good correlations with luminosity, although more luminous clusters tend to be more concentrated. When data are binned in luminosity, several trends emerge: more luminous clusters tend to have smaller and denser cores. We interpret this as a differential survival effect, with more massive clusters surviving longer and reaching more evolved dynamical states. Cluster core parameters and concentrations also correlate with the position in the Galaxy, with clusters closer to the Galactic center or plane being more concentrated and having smaller and denser cores. These trends are more pronounced for the fainter (less massive) clusters. This is in agreement with a picture where tidal shocks form disk or bulge passages accelerate dynamical evolution of clusters. Cluster metallicities do not correlate with any other parameter, including luminosity and velocity dispersion; the only detectable trend is with the position in the Galaxy, probably reflecting Zinn's disk-halo dichotomy. This suggests that globular clusters were not self-enriched systems. Velocity dispersions show excellent correlations with luminosity and surface brightness. Their origin is not well understood, but they may well reflect initial conditions of cluster formation, and perhaps even be used to probe the initial density perturbation spectrum on a approximately 10(exp 6) solar mass scale. Core radii and concentrations play a role of a 'second parameter' in these correlations. While a global manifold of cluster properties has a high statistical dimensionality (D greater than 4), a subset of structural, photometric, and dynamical parameters forms a statistically three-dimensional family, as expected from objects following King models; we propose to call this set of quantities the King Manifold. Some of the observed correlations may be usable as distance indicator relations for globular clusters.
Toward a topological characterization of symplectic manifolds

A topological condition is given, characterizing which closed manifolds in dimensions < 8 (and conjecturally in general) admit symplectic structures. The condition is the existence of a certain fibration-like structure called a hyperpencil. A deformation class of hyperpencils on a manifold X of any even dimension is shown to determine an isotopy class of symplectic structures on X. This provides an inverse (at least in dimensions < 8) to Donaldson's program for constructing linear systems on symplectic manifolds. It follows that (at least in dimensions < 8) the set of deformation classes of hyperpencils canonically maps onto the set of isotopy classes of rational symplectic forms up to positive scale, topologically determining a dense subset of all symplectic forms up to an equivalence relation on hyperpencils. Other applications of the main techniques are presented, including the construction of symplectic structures on domains of locally holomorphic maps, and on high-dimensional Lefschetz pencils and other linear systems.
INTERSTELLAR SILICATE DUST IN FIVE QUASAR ABSORPTION SYSTEMS

We report on a study of interstellar silicate dust in five quasar absorption systems at 0.44 < zabs < 1.31 toward quasars Q0235+164, 3C196, Q0852+3435, Q0937+5628, and Q1203+0634, using data from the Infrared Spectrograph on board the Spitzer Space Telescope. In the absorbers toward Q0235+164, 3C196, Q0852+3435, and Q0937+5628, the 9.7 μm silicate feature is detected in absorption at ∼5σ–10σ significance, with rest-frame equivalent widths of ∼0.2–0.5 μm. For Q1203+0634, the noisy data allow us to make only a 3. 6σ detection of absorption at 10 μm. Fits to the redshifted 9.7 μm features with four possible template profiles indicate that the laboratory amorphous olivine profile generally provides the best fit, with inferred peak optical depths of τ9.7 ≈ 0.08–0.18. For three of the quasars with optical spectra available from the Sloan Digital Sky Survey, the Large Magellanic Cloud supershell extinction curve provides the best formal fits, with E(B − V) of 0.34–0.54 mag. A 2175 Å extinction bump at the absorber redshift (known to exist in Q0235+164) appears to be present at >2. 8σ level in Q0852+3435, >2. 5σ level in Q1203+0634, and marginally at nearly 2σ level in Q0937+5628. We briefly explore possible correlations between τ9.7 and the color excess, the strength of the 2175 Å bump, and the metallicity (which appears to be relatively high for these absorbers, in the range of ≳0.1 solar to supersolar). While our measurements are consistent with a linear relation between τ9.7 and E(B − V), the τ9.7/E(B − V) ratios for these quasar absorbers appear to be higher than those for diffuse interstellar clouds in the Milky Way, closer to values observed for the Galactic center. Some of these quasar sightlines may trace regions in the bulges of the galaxies responsible for the absorption systems.
Damped artificial compressibility iteration scheme for implicit calculations of unsteady incompressible flow

Peyret and others have described artificial compressibility iteration schemes for solving implicit time discretizations of the unsteady incompressible Navier-Stokes equations. Such schemes solve the implicit equations by introducing derivatives with respect to a pseudo-time variable τ and marching out to a steady state in τ. The pseudo-time evolution equation for the pressure p takes the form ∂p/∂τ = -a 2 ⊇. u, where a is an artificial compressibility parameter and u is the fluid velocity vector. We present a new scheme of this type in which convergence is accelerated by a new procedure for setting a and by introducing an artificial bulk viscosity b into the momentum equation. This scheme is used to solve the non-linear equations resulting from a fully implicit time differencing scheme for unsteady incompressible flow.
A CONFIGURATION OF THE LASER CAVITY FOR SIMULTANEOUS DUAL WAVELENGTH Q-SWITCH PULSED ND:YALO3 LASER

On the basis of the investigation on the rate equations of the Q-switch simultaneous dual wavelength laser of Nd:YAlO3(Nd:YAP), we have developed a new configuration of the cavity by adjusting the ratio of the cavity lengths for different wavelength lasers according to their emission cross sections. Therefore, the competitive ability and the net gain for the two different wavelengths will be equal at anytime and anywhere in the laser rod, and the optimal spatial and temporal overlap of the two different wavelengths can be easy to realize for optimal sum frequency mixing. In addition, this configuration can overcome several disadvantages of the previously used configurations, and its photon density product integral of the two different wavelengths is about one order larger than the previous ones.
Quantifying Biometric Life Insurance Risks With Non-Parametric Smoothing Methods

Julien Tomas beschrijft verdelingsvrije afrondingsmethoden van de sterfte-ervaring bij levensverzekeringen. Net als parametrische methoden neigen ook deze methoden naar onzuivere schattingen, maar zodanig dat het mogelijk is een grotere onzuiverheid op te laten wegen tegen een lagere steekproefvariatie. De oneffenheden van de ruwe data worden afgevlakt. Afronden is echter meer dan gladmaken. Gladgemaakte kansen moeten de onderliggende data goed weergeven, en afronding zal vaak uitdraaien op een compromis tussen de best mogelijke fit en optimale gladheid. Tomas gebruikt in zijn onderzoek onder meer kwesties over de keuze van de parameters voor het gladmaken, statistische eigenschappen van de schatters, criteria gebruikt bij modelselectie, constructie van betrouwbaarheidsintervallen en vergelijking van de modellen besproken en zowel numeriek als grafisch geillustreerd Overlevingstafels worden gebruikt om de eenjarige sterftekansen te beschrijven in een welomschreven populatie, in functie van de bereikte leeftijd en het kalenderjaar. Zulke kansen spelen een belangrijke rol bij het bepalen van premies en voorzieningen bij levensverzekeringen. De ruwe schattingen waarop overlevingstafels gebaseerd zijn, kunnen worden gezien als een steekproef uit een grotere populatie en zijn daarom onderhevig aan stochastische fluctuaties. Meestal echter wil men deze grootheden
FRACTIONAL BROWNIAN MOTION AND STOCHASTIC EQUATIONS IN HILBERT SPACES

In this paper, stochastic differential equations in a Hilbert space with a standard, cylindrical fractional Brownian motion with the Hurst parameter in the interval (1/2,1) are investigated. Existence and uniqueness of mild solutions, continuity of the sample paths and state space regularity of the solutions, and the existence of limiting measures are verified. The equivalence of the probability laws for the solution evaluated at different times and different initial conditions and the convergence of these probability laws to the limiting probability are verified. These results are applied to specific stochastic parabolic and hyperbolic differential equations. The solution of a specific parabolic equation with the fractional Brownian motion only in the boundary condition is shown to have many results that are analogues of the results for a fractional Brownian motion in the domain.
The alpha -enhanced Isochrones and Their Impact on the FITS to the Galactic Globular Cluster System

We analyze in detail the effect produced by the enhancement of the α-elements O, Ne, Mg, Si, S, and Ca on the evolutionary properties of low-mass, low-metallicity stars. In particular we address the evolutionary phases which extend from the main sequence up to the H reignition on the asymptotic giant branch. We find that the α-elements other than O cannot be neglected
Hopf Semialgebras

In this paper, we introduce and investigate bisemialgebras and Hopf semialgebras over commutative semirings. We generalize to the semialgebraic context several results on bialgebras and Hopf algebras over commutative rings including the main reconstruction theorems and the Fundamental Theorem of Hopf Algebras. We also provide a notion of quantum monoids as Hopf semialgebras which are neither commutative nor cocommutative; this extends the Hopf algebraic notion of a quantum group. The generalization to the semialgebraic context is neither trivial nor straightforward due to the nonadditive nature of the base category of commutative monoids which is also neither Puppe-exact nor homological and does not necessarily have enough injectives.
HYCELL—A new hybrid model of the rain horizontal distribution for propagation studies: 1. Modeling of the rain cell

From radar observations of rain fields at midlatitudes, a new physical model of rain cells is proposed. It strives to describe optimally the rain rate horizontal distribution within rain cells down to 1 mm h−1. The approach is similar to that of the well‐known EXCELL model. The mathematical definition of the model lies in the combination of a gaussian function and an exponential one, the cells having an elliptic horizontal cross section. Due to its hybrid structure, the new model has been named HYCELL. From a conceptual point of view, the gaussian component describes the convective‐like high rain rate core of the cell, while the exponential component accounts for the surrounding stratiform‐like low rain rate spreading down to 1 mm h−1. The modeling of a rain cell with HYCELL then requires the determination of seven parameters. The latter is obtained, cell by cell, by solving a set of five fit‐forcing equations completed by two continuity equations. The fit‐forcing equations involve radar parameters of integral nature which refer not only to the rain cell geometry (area, ellipticity) but also to the rain rate R distribution inside the cell (mean and root mean square values of R and gradient of R). Their analytical expressions are derived from the model definition, while their values are forced to be those derived from radar measurements. Using this method, thousands of rain cells identified from radar observations in the regions of Bordeaux (southwestern France) and Karlsruhe (southwestern Germany) have been modeled. Though both sites are at midlatitude, the climatic contexts differ: oceanic for Bordeaux and continental for Karlsruhe. Results of rain rate horizontal distribution modeling within cells using HYCELL and EXCELL are compared. It is then suggested that the HYCELL model is a new tool which deserves to be considered by system designers to compute propagation parameters.
Modeling cirrus clouds. Part II: Treatment of radiative properties

Abstract A new radiation scheme, suitable for two-stream radiation transfer models, was developed for cirrus clouds. Analytical expressions were derived for the extinction and absorption coefficients and the asymmetry parameter. These are functions of the ice particle size distribution parameters, ice particle shapes, and wavelength. The ice particle shapes considered were hexagonal plates and columns, bullet rosettes, and planar polycrystals. These appear to be the principal crystal types found in cirrus clouds. The formulation of radiative properties accounts for the size distribution projected area and the distance radiation travels through ice particles. For absorption, refraction and internal reflection of radiation were parameterized. By assuming an idealized cirrus cloud, the dependence of the single scatter albedo, reflectance, and emissivity on wavelength, ice particle shape, and size distribution was demonstrated. Reflectance and emissivity exhibited a strong dependence on ice particle shape, wi.