Miracle-dz/UniFAR-FTUs huggingface dataset:
The truncation model of the derivative nonlinear Schrödinger equation

The derivative nonlinear Schrodinger (DNLS) equation is explored using a truncation model with three resonant traveling waves. In the conservative case, the system derives from a time-independent Hamiltonian function with only one degree of freedom and the solutions can be written using elliptic functions. In spite of its low dimensional order, the truncation model preserves some features from the DNLS equation. In particular, the modulational instability criterion fits with the existence of two hyperbolic fixed points joined by a heteroclinic orbit that forces the exchange of energy between the three waves. On the other hand, numerical integrations of the DNLS equation show that the truncation model fails when wave energy is increased or left-hand polarized modulational unstable modes are present. When dissipative and growth terms are added the system exhibits a very complex dynamics including appearance of several attractors, period doubling bifurcations leading to chaos as well as other nonlinear pheno.
Non�?Parametric Regression Under Location Shifts

Recent work by Wang and Phillips (2009b, 2011) has shown that ill‐posed inverse problems do not arise in non‐stationary non‐parametric regression and there is no need for non‐parametric instrumental variable estimation. Instead, simple Nadaraya–Watson non‐parametric estimation of a cointegrating regression equation is consistent irrespective of the endogeneity in the regressor. The present paper shows that some closely related results apply in the case of structural non‐parametric regression with independent data when there are continuous location shifts in the regressor. Some interesting cases are discovered where non‐parametric regression is consistent, whereas parametric regression is inconsistent even when the true regression functional form is known and used in regression. This appears to be a paradox, as knowing the true functional form should not in general be detrimental in regression. The paradox arises because additional correct information is not necessarily advantageous when information is incomplete. In this case, endogeneity in the regressor introduces bias when the true functional form is known, but interestingly does not do so in local non‐parametric regression. We propose two new consistent estimators for the parametric regression, which address the endogeneity in the regressor by means of spatial bounding and bias correction using non‐parametric estimation.
Statistics of N-body simulations — IV. Unequal masses with a tidal field

We report results of a large number of collisional N-body simulations including a mass spectrum and a tidal field. We emphasize the ways in which evolution differs from that observed in isolated systems, by comparison with earlier papers in this series. We show that the evolution hardly alters if the tidal field is replaced by a tidal cut-off. Core collapse is almost unaffected by the tide, but the subsequent post collapse expansion is eventually reversed by the time that tidal limitation becomes important. As in isolated models, mass segregation almost stops by the end of core collapse; after core bounce there is a substantial increase in the mean mass, caused by preferential escape of stars of low mass. The early phase of rapid mass segregation is also characterized by an approach to equipartition in the inner parts of the system, although the outer parts remain far from equipartition. Even here, however, there is a slow tendency to equipartition in post-collapse expansion, as the tidal stripping of the outer parts gradually exposes parts of the cluster where equipartition was partially established. Similar remarks apply to the evolution of the anisotropy. The evolution of the core is vIrtually unaffected by the tide until well after core bounce; in late post-collapse evolution there is a tendency for the mass of the core to decrease slightly, whereas it is nearly constant in isolated models. Similarly, in the presence of a tide the mean number of binaries in the system tends to decrease after the end of core collapse. The total internal binding energy in bound binaries is smaller than at comparable stages of post-collapse evolution in isolated systems. In the overall energy budget, one obvious difference between isolated and tidally limited models is that the energy of escaping single stars is initially negative, although it becomes positive later as the energy carried off by ejecta from three body interactions becomes dominant.
Algebras stably equivalent to selfinjective algebras whose Auslander-Reiten quivers consist only of generalized standard components

Throughout the paper K denotes a fixed algebraically closed field. All algebras considered are finite-dimensional associative K-algebras with a unit element. Moreover, they are assumed to be basic and connected. For an algebra A we denote by mod(A) the category of all finitely generated right A-modules, and mod(A) denotes the stable category of mod(A), i.e. mod(A)/℘ where ℘ is the two-sided ideal in mod(A) of all morphisms that factorize through projective A-modules. Two algebras A and B are said to be stably equivalent if the stable categories mod(A) and mod(B) are equivalent. The study of stable equivalences of algebras has its sources in modular representation theory of finite groups. It is of importance in this theory whether two stably equivalent algebras have the same number of pairwise non-isomorphic nonprojective simple modules. Another motivation for studying stable equivalences appears in the following context. If E is a K-algebra of finite global dimension then its derived category Db(E) is equivalent to the stable category mod(Ê) of the repetitive category Ê of E [15]. Thus the problem of a classification of derived equivalent algebras leads in many cases to a classification of stably equivalent selfinjective algebras.
Applying complex network theory to the understanding of high-aspect-ratio carbon-filled composites

This work demonstrates that the theoretical framework of complex networks typically used to study systems such as social networks or the World Wide Web can be also applied to material science, allowing deeper understanding of fundamental physical relationships. In particular, through the application of the network theory to carbon nanotubes or vapour-grown carbon nanofiber composites, by mapping fillers to vertices and edges to the gap between fillers, the percolation threshold has been predicted and a formula that relates the composite conductance to the network disorder has been obtained. The theoretical arguments are validated by experimental results from the literature.
Thermal fracture in a biomaterial during rapid freezing

Thermal stresses leading to fracture during rapid freezing of a biomaterial are studied using potato tissues as an example. The thermal model includes the gradual freezing of the tissue, that is, the presence of a mushy zone. Water in the biomaterial expands almost 9% during freezing and develops transient stresses when the material is frozen from all sides. A viscoelastic model for the tissue is used with mechanical properties changing continuously during freezing. A comparison of stresses developed during freezing, with experimentally measured failure strength, is used as a criterion for initiation of a crack. The strain energy release rate G is calculated using the J integral. Experimental evidence of a catastrophic fracture during very rapid freezing (boundary temperature of 200 C) suggests that the G value is likely to exceed the critical rate (G) at this temperature but not so for slow freezing at a boundary temperature of c.40 C, for which no experimental fractures are observed. A multistep freezin.
CLASSIFICATION OF DACRYODES EDULIS (G. DON) H.J. LAM BY USING MORPHOLOGICAL AND PHYSICAL CHARACTERISTICS OF THE FRUITS: A STATISTICAL APPROACH

ABSTRACT Safous (2270 fruits) picked on 227 safou trees from Franceville (southeast Gabon) were studied for their morphological and physical characteristics including fruit length, fruit width, fruit volume, fruit mass, pulp thickness, pulp mass, specific gravity and pulp mass/fruit mass ratio. All these characteristics showed continuous and considerable variation, the highest coefficients of variation being recorded for fruit mass (36%), fruit volume (39%) and pulp mass (45%). Data were treated by multivariate statistics tools. Principal Components Analysis (PCA) permitted to select three variables (fruit mass, fruit length and fruit width) for safous classification. Three safous classes were defined by Ascending Hierarchical Clustering (AHC) and these three classes were confirmed by Factorial Discriminant Analysis (FDA) with 94.7% of the population correctly classified. One class is composed of small-size fruits and the other two classes, relatively near, corresponded to medium-size fruits. A model to classify new trees is proposed.
Compressional waves in complex (dusty) plasmas under microgravity conditions

Complex plasmas consist of electrons, ions and charged microparticles, with typical charge-to-mass ratios 1:10−5:10−13. The interest in these systems has grown explosively, because they can be investigated at the kinetic level (the microparticles). However, on Earth the supporting forces (against gravity) are of the same order as the electrostatic interparticle forces—and hence only strongly compressed systems can be investigated. Under microgravity conditions these “body forces” are a factor 102 smaller which allows the experimental investigation of weakly compressed three-dimensional complex plasmas. One way to study these systems is by the controlled excitation of low-frequency compressional waves. The first such experiments, conducted with the PKE-Nefedov laboratory on the International Space Station is reported. The waves were excited by modulating the voltage on the rf electrodes. By varying the modulation frequency the dispersion relation was measured. The results are compared with existing theoret.
On critically perfect graphs

A perfect graph is critical, if the deletion of any edge results in an imperfect graph. We give examples of such graphs and prove some basic properties. We relate critically perfect graphs to well-known classes of perfect graphs, investigate the structure of the class of critically perfect graphs, and study operations preserving critical perfectness. © 1999 John Wiley & Sons, Inc. J Graph Theory 32: 394–404, 1999
A generalized multistate-based path vector approach to multistate two-terminal reliability

The two-terminal reliability problem assumes that a network and its elements are either in a working or a failed state. However, many practical networks are built of elements that may operate in more than two states i.e., elements may be degraded but still functional. Multistate two-terminal reliability at demand level d (M2TR d ) can be defined as the probability that the system capacity generated by multistate components is greater than or equal to a demand of d units. This paper presents a fully multistate-based algorithm that obtains the multistate equivalent of binary path sets, namely, Multistate Minimal Path Vectors (MMPVs), for the M2TR d problem. The algorithm mimics natural organisms in the sense that a select number of arcs inherit information from other specific arcs contained in a special set called the “primary set. ” The algorithm is tested and compared with published results in the literature. Two features of the algorithm make it relevant: (i) unlike other approaches, it does not depend on an a priori knowledge of the binary path sets to obtain the MMPVs; and (ii) the use of an information sharing approach and network reduction technique significantly reduce the number of vector analyses needed to obtain all the component levels that guarantee system success. Additionally, the complexities associated with the computation of reliability are discussed. A Monte Carlo simulation approach is used to obtain an accurate estimate of actual M2TR values based on MMPVs. Examples are used to validate the algorithm and the simulation procedure.
Thematic information content assessment of the ASTER GDEM: a case study of watershed delineation in West Java, Indonesia

This study assesses the thematic information content using subwatershed boundaries mapped using advanced spaceborne thermal emission and reflection (ASTER) global digital elevation model (GDEM), shuttle radar topography mission (SRTM) DEM and a topographic map (Topo-DEM), and verifies the absolute elevation accuracy by the use of a real-time kinematic differential global positioning system (RTK-DGPS) survey. Subwatershed boundaries extracted from the three different DEMs exhibit a high degree of congruency especially in upstream areas. In these areas, SRTM exhibits lower root mean square errors (RMSEs) than the ASTER GDEM. The discrepancies were larger at lower altitudes. The vertical accuracy assessment using the RTK-DGPS data showed strong correlation with the three DEMs at some stations but the accuracy varied from one area to another. The ASTER GDEM and SRTM had lower accuracy than the Topo-DEM due to the influence of artefacts as shown by their total average RMSE (4.42, 3.30 and 3.13 m, respectively). The average RMSE values also indicate that SRTM is comparatively more accurate than ASTER GDEM.
Dynamic magneto-optical imaging of transport current redistribution and normal zone propagation in YBa2Cu3O7−δ coated conductor

YBa2Cu3O7−δ (YBCO) coated conductors carry high critical current density with the potential for low cost and thus have a broad range of potential applications. An unresolved issue that could inhibit implementation, however, is a lack of understanding of the current redistribution and normal zone propagation behavior in the event of a thermal disturbance (quench). In this work, we for the first time present the real-time, dynamic observation of magnetic field redistribution during a thermal disturbance via magneto-optical imaging with a high speed, high resolution CCD (charge coupled device) camera. The optical images are converted to a two-dimensional, time-dependent data set that is then analyzed quantitatively. It is found that the normal zone propagates non-uniformly in two dimensions within the YBCO layer. Two stages of normal zone propagation are observed. During the first stage, the normal zone propagates along the conductor length as the current and magnetic field redistribute within the YBCO layer. During the second stage, current sharing with the Cu begins and the magneto-optical image becomes constant. The normal zone propagation velocity at 45 K, I = 50 A (∼50% Ic), is determined as 22.7 mm s−1 using the time-dependent optical light intensity data.
Colorless chalco-halide Ga2S3-GeS2-CsCl glasses as new optical material

Colorless sulfide glasses can be obtained by selecting appropriately the composition within the Ga2S3-GeS2-CsCl pseudo-ternary glass system. The addition of electronegative chlorine ions into the sulfide glassy network results in a widening of its optical bandgap without altering its infrared transparency. Glasses transparent from the near UV (380 nm) up to the middle infrared (11.5 μm) are thus achievable. Such extended infrared transmission for a colorless glass is the widest among the known heavy metal oxide and fluoride glasses, e.g. fluoroindate glasses are transparent from 350 nm up to 8-9 μm. We present in this work our recent progress on the preparation of this chloro-sulfide glass of high optical quality. Efforts have been devoted in a first step to reduce the content of extrinsic impurities such as OH, SH and H2O. In a second step, protective coatings have been deposited on polished glass samples to improve their chemical durability and assess their potential for practical applications. Large improvement of both optical quality, in terms of transmission spectrum flattening, and chemical durability were achieved. Finally, the high thermal stability against crystallization of this glass shows a high potential for lens molding and applications in multispectral imaging.
Statistical energy analysis: a critical overview

For the benefit of the ‘enquirer within’, who may not be familiar with the background and concepts of SEA, this overview opens with a discussion of the rationale for the use of probabilistic energetic models for high-frequency vibration prediction, and introduces the postulate upon which conventional SEA is based. It compares and relates the modal and travelling wave approaches, discusses the strengths and weaknesses of SEA as currently practised and points out needs and directions for future research. Critical discussions of individual contributions to the development of the subject are presented only in as much as they treat specific matters of concept, principle or reliability. The roles of SEA in providing a framework for experimental investigations of the high-frequency dynamic behaviour of systems and in interpreting observations on operating systems, although equally important, are not substantially addressed. Nor are specific experimental techniques which involve considerations of transducers, spatial sampling, signal processing, error analysis and data interpretation, which require a critical review in their own right.
Projective Differential Geometrical Structure of the Painlevé Equations

Abstract The necessary and sufficient conditions that an equation of the form y″=f(x, y, y′) can be reduced to one of the Painleve equations under a general point transformation are obtained. A procedure to check these conditions is found. The theory of invariants plays a leading role in this investigation. The reduction of all six Painleve equations to the form y″=f(x, y) is obtained. The structure of equivalence classes is investigated for all the Painleve equations. Following Cartan the space of the normal projective connection which is uniquely associated with any class of equivalent equations is considered. The specific structure of the spaces under investigation allows us to immerse them into R P3. Each immersion generates a triple of two-dimensional manifolds in R P3. The surfaces corresponding to all the Painleve equations are presented.
Population Dynamics and Random Genealogies

We start with stochastic models of genealogies in discrete time, distinguishing models where the population size is fixed (models of Cannings, Wright–Fisher, and Moran; compositions of bridges) with models where the population size fluctuates randomly (processes of Bienaymé–Galton–Watson, Jirina; birth–death processes, logistic branching process). Scaling limits of these models can be seen as genealogies of continuous populations. The continuous analogue of models with a fixed size is the stochastic flow of bridges of Bertoin and Le Gall. That of branching models is the continuous-state branching process. Both processes have diffusion versions called, respectively, the Fisher–Wright diffusion and the Feller diffusion. Connections between the two kinds of models are also studied, and special attention is given to extinction/fixation (probability, expected time, conditioning). When (sub)populations are bound to extinction, the distribution of their size conditional on extinction, either not to have occurred yet or to occur in the distant future, converges in many situations. The limits are called quasi-stationary distributions and provide a rigorous notion for the dynamics of populations which seem stable at least on the human time-scale. We display quasi-stationarity for all models introduced previously, tackling the problem of uniqueness of quasi-stationary distributions, and comparing different conditionings (Q-process). In a slightly different setting, we prove that the contour process of splitting trees with general lifetime is a killed Lévy process, and use this observation to derive a certain number of properties of these trees, including connections between Lévy processes and branching processes (one by Le Gall and Le Jan and another one by Bertoin and Le Gall), and a generalization of the coalescent point process of Aldous and Popovic. These two kinds of results open up to more general problems such as Ray–Knight type theorems on the one hand, and coalescent processes on the other hand.
On Realizability of a Set of Integers as Degrees of the Vertices of a Linear Graph. I

This paper is mainly concerned with the realizability of a set of n integers as the degrees of vertices of an n-vertex linear graph. Other related problems, such as when a set of integers is realizable as a connected graph, connected graph without “parallel” elements, separable graph, and nonseparable graph, are considered. The relationship between this problem and the problem of isomers in the organic chemistry is described. A similar problem in weighted graphs is also studied.
The degree of differentiability of the regularization of simultaneous binary collisions in some N-body problems

Simultaneous binary collisions in the four-body problem are studied in the cases which reduce to one-dimensional problems: the collinear, bi-isosceles and trapezoidal cases and the tetrahedron problem, some of them requiring certain symmetries of the masses. It is shown that in all of these cases the regularization is differentiable but the map passing from initial to final conditions (in some suitable transversal sections) is exactly C8/3. Then the result is extended to other symmetric N-body problems.
What Determines the Height of Spicules? I. Alfvén-Wave Model and Slow-Wave Model

We perform numerical simulations for torsional Alfvén waves and slow waves propagating along an open magnetic flux tube in the solar atmosphere to elucidate the mechanisms of spicule formation and coronal heating. We introduce random motions of about 1 km s-1 in the photosphere as the source of Alfvén and slow waves, and solve the 1.5-dimensional magnetohydrodynamic equations. The waves generated by the random motions propagate upward and lift up the transition region. The chromospheric plasma just below the transition region is thought to be observed as a spicule. We investigate the effect of the initial height of the transition region, or transition-region pressure, on spicule formation. Our results agree well with the observational fact that spicules are absent over plages, where the transition-region pressure is high, and tall under coronal holes, where the transition-region pressure is low. We also show that the dependence of spicule height on the initial transition-region height (or pressure) is well described by the theoretical relation, which is for the slow-wave acceleration of spicules even though we input only Alfvén waves in the photosphere. Although both fast and slow waves are excited by the nonlinear coupling of Alfvén waves, our results suggest that the slow waves play a more fundamental role in the generation of spicules. How much energy flux is transported to the corona is also estimated. A part of the energy flux carried by the waves that generate spicules propagates into the corona and contributes to the heating of the corona. Alfvén waves can transport enough energy flux to heat the quiet corona, but slow waves cannot.