Miracle-dz/UniFAR-FTUs huggingface dataset:
Role of atomic structure on grain boundary-defect interactions in Cu

We investigate the role that the atomic structure of grain boundaries in Cu has in the interaction with point defects produced during irradiation. We focus on three aspects of defect-boundary interaction: how defects interact with pristine boundaries, how boundaries modify defect production during collision cascades, and how defects interact with damaged boundaries. We find that there are generic features common to most boundaries, including biased absorption of interstitials over vacancies during collision cascades and strong interactions with vacancies for interstitial-loaded boundaries. However, we find that the magnitude of these behaviors depends strongly on the atomic structure of the boundary. In particular, the biased absorption is much stronger for a high angle twist boundary and smallest for a more general twist-asymmetric tilt boundary. Further, the strength of defect-boundary interactions is also sensitive to the boundary structure. We conclude that the sink strength of grain boundaries for interacting with point defects is not an intrinsic property of the boundary but rather depends on the irradiation condition through the absorbed defect content at the boundary.
Convergence analysis of adaptive biasing potential methods for diffusion processes

This article is concerned with the mathematical analysis of a family of adaptive importance sampling algorithms applied to diffusion processes. These methods, referred to as Adaptive Biasing Potential methods, are designed to efficiently sample the invariant distribution of the diffusion process, thanks to the approximation of the associated free energy function (relative to a reaction coordinate). The bias which is introduced in the dynamics is computed adaptively; it depends on the past of the trajectory of the process through some time-averages. We give a detailed and general construction of such methods. We prove the consistency of the approach (almost sure convergence of well-chosen weighted empirical probability distribution). We justify the efficiency thanks to several qualitative and quantitative additional arguments. To prove these results , we revisit and extend tools from stochastic approximation applied to self-interacting diffusions, in an original context.
Convergence to the boundary for random walks on discrete quantum groups and monoidal categories

We study the problem of convergence to the boundary in the setting of random walks on discrete quantum groups. Convergence to the boundary is established for random walks on $\hat{\textrm{SU}_q(2)}$. Furthermore, we will define the Martin boundary for random walks on C$^*$-tensor categories and give a formulation for convergence to the boundary for such random walks. These categorical definitions are shown to be compatible with the definitions in the quantum group case. This implies that convergence to the boundary for random walks on quantum groups is stable under monoidal equivalence.
A survey of galaxy redshifts. III - The density field and the induced gravity field

We have recently completed a redshift survey of galaxies complete to 14.5 m/sub Z/ in the north and south galactic polar caps containing some 2400 objects. Using an estimator unbiased by the known inhomogeneity of matter, we here compute the number density and luminosity density of bright galaxies to a distance of 80 Mpc (H/sub 0/ = 100) over the 2.7 sr of the survey. A plot of density versus distance vividly demonstrates the existence of a region 30 Mpc in extent beyond the Virgo cluster that is underdense by nearly a factor of 2 from the mean. However, averaging over the full sample volume of 4 x 10/sup 5/ Mpc/sup 3/, the number density and luminosity density given in the north catalogs agree to within 7%, suggesting that the survey is perhaps approaching a fair sample volume of the universe. The mean overdensity delta-bar toward the Virgo cluster is measured to be 2.0 +- 0.2, an important number for Virgocentric estimates of . cap omega. Finally, we examine the local peculiar gravity g induced by the inhomogeneous distribution of matter at large distances, assuming mass density to be at least approximately distributed as the large scale number density of galaxies.more » In the limit of linear perturbation theory, g is proportional to the expected peculiar motion of the local group v/sub p/, for which we derived Vertical Bar v/sub p/ Vertical Barapprox.670 . cap omega. /sup 0.6/, directed roughly toward the Virgo cluster. The assumptions of this cosmological test are quite different from the nonlinear spherically symmetric Virgo infall test, and yet they both yield estimates of . cap omega. that are quite high, 0.4<. cap omega. <0.5, for an adopted infall velocity of 400 km s/sup -1/. If the infall is as high as 500 km s/sup -1/, the universe could very well be closed. However, if the infall is only 300 km s/sup -1/, . cap omega. is roughly one-third of the closure density. « less
Reaction-diffusion processes and evolution to harmonic maps

Initial-boundary value problems are considered for the reaction-diffusion equation $u_1 = \varepsilon \Delta u - \varepsilon ^{ - 1} f( u )$ with x in a domain $\Omega $ in $R''$ and u in $R'''$. First the asymptotic behavior of u is determined for $\varepsilon $ small when $f( u ) = 0$ on a connected manifold M of stable equilibrium points. It is found that a tends rapidly to M, being driven by reaction. Then u evolves slowly by diffusion restricted toM. It tends ultimately to a limit that is a harmonic map of $\Omega $ into M Next, the case where $f( u )$ has stable equilibrium points on two manifolds $M_1 $ and $M_2 $ is treated. In this case a front develops in $\Omega $, It separates the regions where u is close to $M_1 $, from the regions whereu is close to $M_2 $. For $f( u ) = V_n ( u )$ a boundary layer solution is constructed for u near the front, and the velocity of the front is found to be proportional to the jump in V across it, to leading order in $\varepsilon $. When $V( u )$ has the same v.
Co‐infection of peste des petits ruminants and goatpox in a mixed flock of sheep and goats in Kanam, North Central Nigeria

Abstract Peste‐des‐petits‐ruminants (PPR) and Goat pox (GTP) are two devastating and economically important transboundary animal diseases of small ruminants in Africa and Asia that have been difficult to control. This study however, investigated an outbreak of PPR and GTP in a mixed flock of indigenous sheep and goats in Kanam, North Central Nigeria. A total of nine sera and seven tissues (lungs, spleen, scab and skin) samples were collected and analysed in the laboratory using competitive enzyme linked immunosorbent assay (cELISA) for PPR antibodies and polymerase chain reaction (PCR) for detection of PPR virus (PPRV) and GTP virus (GTPV). Gene fragments of the nucleoprotein of PPRV and the G‐protein‐coupled chemokine receptor (GPCR) of GTPV were amplified and sequenced to confirm the presence of the causative viruses. Serologically, antibodies to PPRV were detected in all (9/9) sera collected. GTPV and PPRV was detected in corresponding samples (42.8% n = 3/7) of the scab/skin samples collected by both PCR and RT‐PCR technique. The phylogenetic analysis of PPRV revealed that the virus belongs to lineage IV and clustered with viruses from Gabon and Cameroon. Similarly, the GTPV also clustered with other sequences from Burkina Faso and Yemen. The positive cELISA, RT‐PCR and PCR results from samples collected from the same animals confirmed co‐infection of PPR and GTP in this mixed flock of sheep and goats. This is the first report of concurrent infection of PPR and GTP in mixed flock of sheep and goats in Nigeria. Our findings underscore the need for farmers to vaccinate their flock to control spread and economic losses as result of these diseases.
Translation operator with exceptional Laguerre polynomials

We extend the notion of general translation operator to exceptional Laguerre polynomials. To this we investigate the associated singular hyperbolic Cauchy problem. We derive a maximum principle with respect to this Cauchy problem and applying it we determine the norm of the translation operator. As an application we give Nikol'skii inequalities with respect to exceptional Laguerre polynomials.
Production and Dissipation of Vorticity in a Turbulent Fluid

In some recent publications (Taylor 1937; Taylor and Green 1937) the author has put forward the view that the high average vorticity which is known to exist in turbulent motion is caused by the extension of vortex filaments in an eddying fluid. Let A and B be two particles a short distance, d , apart on a vortex line where the vorticity is ω . At a subsequent time when the distance between A and B has changed from d to d and the vorticity from ω to ω then, neglecting the effects of viscosity, the equation representing the conservation of circulation is ω / ω = d / d . (1) Turbulent motion is found to be diffusive, so that particles which were originally neighbours move apart as the motion proceeds. In a diffusive motion the average value of d 2/ d 2 continually increases. It will be seen therefore from (1) that the average value of ω 2/ ω 2 continually increases. An equation for the average rate of increase in ω 2 has been given by v. Karman (1937) which contains the term ω 2 ∂ u 3/∂ x 3, where the bar shows that the average value has been taken and ∂ u 3/∂ x 3 represents the rate of stretching of vortex filaments.
Rapid mixing in Markov chains

A wide class of ``counting'' problems have been studied in Computer Science. Three typical examples are the estimation of - (i) the permanent of an $n\times n$ 0-1 matrix, (ii) the partition function of certain $n-$ particle Statistical Mechanics systems and (iii) the volume of an $n-$ dimensional convex set. These problems can be reduced to sampling from the steady state distribution of implicitly defined Markov Chains with exponential (in $n$) number of states. The focus of this talk is the proof that such Markov Chains converge to the steady state fast (in time polynomial in $n$). A combinatorial quantity called conductance is used for this purpose. There are other techniques as well which we briefly outline. We then illustrate on the three examples and briefly mention other examples.
This paper is included in the Proceedings of the 32nd USENIX Security Symposium.

EDHOC is a key exchange proposed by IETF’s Lightweight Authenticated Key Exchange (LAKE) Working Group (WG). Its design focuses on small message sizes to be suitable for constrained IoT communication technologies. In this paper we provide an in-depth formal analysis of EDHOC–draft version 12, taking into account the different proposed authentication methods and various options. For our analysis we use the S APIC + protocol platform that allows to compile a single specification to 3 state-of-the-art protocol verification tools (P ROVERIF , T AMARIN and D EEP S EC ) and take advantage of the strengths of each of the tools. In our analysis we consider a large variety of compromise scenarios, and also exploit recent results that allow to model existing weaknesses in cryptographic primitives, relaxing the perfect cryptography assumption, common in symbolic analysis. While our analysis confirmed security for the most basic threat models, a number of weaknesses were uncovered in the current design when more advanced threat models were taken into account. These weaknesses have been acknowledged by the LAKE WG and the mitigations we propose (and prove secure) have been included in version 14 of the draft.
A family of Crouzeix–Raviart finite elements in 3D

In this paper, we will develop a family of non-conforming “Crouzeix–Raviart” type finite elements in three dimensions. They consist of local polynomials of maximal degree [Formula: see text] on simplicial finite element meshes while certain jump conditions are imposed across adjacent simplices. We will prove optimal a priori estimates for these finite elements. The characterization of this space via jump conditions is implicit and the derivation of a local basis requires some deeper theoretical tools from orthogonal polynomials on triangles and their representation. We will derive these tools for this purpose. These results allow us to give explicit representations of the local basis functions. Finally, we will analyze the linear independence of these sets of functions and discuss the question whether they span the whole non-conforming space.
VARIATIONS IN THE STRUCTURE OF THE UPPER WESTERLIES

Abstract This study indicates that the jet streams which are observed on meridional cross sections appear first at high latitudes and usually shift slowly southward to low latitudes, where they eventually disappear. It is common to observe the presence of more than one upper west-wind maximum at the same time but at different latitudes. Average variations in the speeds of these maxima are studied. Splitting of a single west-wind maximum into two distinct maxima is occasionally observed on a hemispheric scale.
Surface Waves, Limiting Waves and Exceptional Waves: David Barnett's Role in the Development of the Theory

A short review is presented of progress in the theory of localized eigenwaves in anisotropic solids. The main attention is paid to the problem of existence of surface wave solutions in semi-infinite elastic bodies. Here the contribution of David Barnett is most important. The general theorems of existence and uniqueness are formulated and their modifications for media with piezoelectric and/or piezomagnetic couplings are considered. The conditions for existence of supersonic surface waves in purely elastic half-spaces are displayed. The situations on both sides of the vicinity of exceptional transonic states are discussed. The criterion for the existence of quasi-bulk subsonic surface waves in elastic media of unrestricted anisotropy is obtained in terms of the general Barnett and Lothe theorem. The conditions for the existence of exceptional bulk waves and their main properties are considered. The interface wave theory of David Barnett et al is reviewed for rigid and slip contacts between elastic and piezoelectric sub-media.
Accurate oscillator strengths for interstellar ultraviolet lines of Cl I

Analyses on the abundance of interstellar chlorine rely on accurate oscillator strengths for ultraviolet transitions. Beam-foil spectroscopy was used to obtain f-values for the astrophysically important lines of Cl I at 1088, 1097, and 1347 A. In addition, the line at 1363 A was studied. Our f-values for 1088, 1097 A represent the first laboratory measurements for these lines; the values are f(1088)=0.081 +/- 0.007 (1 sigma) and f(1097) = 0.0088 +/- 0.0013 (1 sigma). These results resolve the issue regarding the relative strengths for 1088, 1097 A in favor of those suggested by astronomical measurements. For the other lines, our results of f(1347) = 0.153 +/- 0.011 (1 sigma) and f(1363) = 0.055 +/- 0.004 (1 sigma) are the most precisely measured values available. The f-values are somewhat greater than previous experimental and theoretical determinations.
The Evolution of Cloud-to-Ground Lightning within a Portion of the 10 11 June 1985 Squall Line

Abstract The character of cloud-to-ground lightning is examined during the life cycle of a distinct mesoscale segment of the 10–11 June 1985 mesoscale convective system (MCS). Three phases of lightning activity are identified and related to both the radar-observed structure of the convection and to the severe weather produced by the MCS. Positive strikes to ground are dominant when the MCS is first developing. Negative strikes then dominate during a period of intense leading-line convective activity with high storm tops. Finally, a period of relatively frequent positive strikes within the trailing stratiform region occurs during the demise of the MCS. This last phase begins after the vertical extent of the leading convective line decreases rapidly and markedly, with moderate intensity echoes (i.e., 30–40 dBZ) occurring mostly below the freezing level. The first period of frequent positive flashes results from the lightning associated with a single severe thunderstorm in southwest Kansas; however, a second.
Lessons for Loop Quantum Gravity from Parametrised Field Theory

In a series of seminal papers, Laddha and Varadarajan have developed in depth the quantisation of Parametrised Field Theory (PFT) in the kind of discontinuous representations that are employed in Loop Quantum Gravity (LQG). In one spatial dimension (circle) PFT is very similar to the closed bosonic string and the constraint algebra is isomorphic to two mutually commuting Witt algebras. Its quantisation is therefore straightforward in LQG like representations which by design lead to non anomalous, unitary, albeit discontinuous representations of the spatial diffeomorphism group. In particular, the complete set of (distributional) solutions to the quantum constraints, a preferred and complete algebra of Dirac observables and the associated physical inner product has been constructed. On the other hand, the two copies of Witt algebras are classically isomorphic to the Dirac or hypersurface deformation algebra of General Relativity (although without structure functions). The question we address in this paper, also raised by Laddha and Varadarajan in their paper, is whether we can quantise the Dirac algebra in such a way that its space of distributional solutions coincides with the one just described. This potentially teaches us something about LQG where a classically equivalent formulation of the Dirac algebra in terms of spatial diffeomorphism Lie algebras is not at our disposal. We find that, in order to achieve this, the Hamiltonian constraint has to be quantised by methods that extend those previously considered. The amount of quantisation ambiguities is somewhat reduced but not eliminated. We also show that the algebra of Hamiltonian constraints closes in a precise sense, with soft anomalies, that is, anomalies that do not cause inconsistencies. We elaborate on the relevance of these findings for full LQG.
Extreme Event Quantification in Dynamical Systems with Random Components

A central problem in uncertainty quantification is how to characterize the impact that our incomplete knowledge about models has on the predictions we make from them. This question naturally lends itself to a probabilistic formulation, by making the unknown model parameters random with given statistics. Here this approach is used in concert with tools from large deviation theory (LDT) and optimal control to estimate the probability that some observables in a dynamical system go above a large threshold after some time, given the prior statistical information about the system's parameters and/or its initial conditions. Specifically, it is established under which conditions such extreme events occur in a predictable way, as the minimizer of the LDT action functional. It is also shown how this minimization can be numerically performed in an efficient way using tools from optimal control. These findings are illustrated on the examples of a rod with random elasticity pulled by a time-dependent force, and the nonlinear Schrodinger equation (NLSE) with random initial conditions.
Sound attenuation as a function of depth in the sea floor

Recently published data on the attenuation of compressional (sound) waves in marine sediments and sedimentary rocks as a function of frequency and sediment porosity have been added to previously published figures. The revised figure illustrating attenuation as a function of frequency (5 Hz–1 MHz), and attendant discussion, continue to support the conclusion that attenuation is approximately related to the first power of frequency in sands, muds, and sedimentary rocks. The revised figure illustrating sediment porosity versus attenuation affirms that sediment porosity is an important index property which can be used to predict sound attenuation in surficial sediments. Data were collected and illustrated on sound attenuation as a function of depth in the sea floor. It is concluded that attenuation decreases with about the −1/6 power of depth in sands. As a silt–clay sediment (mud), or turbidite, is placed under increasing overburden pressure, there may be a progressive increase in attenuation due to reductio.
Spectra in the vacuum ultraviolet region of CO in gaseous and solid phases and dispersed in solid argon at 10 K

With radiation in the region 104–170 nm from a synchrotron and dispersed with a grating monochromator at spectral resolution 0.02–0.03 nm, we measured absorption spectra of 12C16O in the gaseous phase at 303 K and in the solid phase at 10 K, and dispersed in solid argon at molar ratios Ar:CO = 10, 50 and 250 and at 10 K. We assign observed spectral features to transitions to electronic states A 1Π, B 1Σ+, C 1Σ+ and E 1Π from the ground state X 1Σ+. Vibrational progressions are discernible for all these systems of CO in the gaseous phase, but for only the system A—X for CO in the pure solid phase of CO or a dispersion in solid argon; for all condensed phases, multiple series of features are deducible in this vibrational structure.
Multiscale structures in relativistic pair plasmas

The steady-state solution of a pair plasma with relativistic thermal velocity of the constituent particles (electrons and positrons) is investigated. The relaxed state can be written as a superposition of three Beltrami fields. Generally, the associated scale parameters could be a complex conjugate pair and a real one. It is shown that at higher thermal energies, all the scale parameters become real. It is also observed that one component gets a large scale (system size) while the other two components appear with small scale of the order of the skin depth at relativistic temperature.
Luminescence in CaSO4 : Dy phosphor - dependence on grain agglomeration, sintering temperature, sieving and washing

In the recently developed high-sensitive CaSO4 : Dy phosphor, sieving before the high-temperature sintering treatment has successfully eliminated particle agglomeration during subsequent sintering, and has further enhanced its thermostimulated luminescence (TSL) sensitivity to γ-rays. The reduction in TSL sensitivity of higher sized grains observed earlier following the procedure of sieving after sintering has also more or less vanished. Maximum TSL sensitivity is seen after sintering around 700°C, whereas maximum photoluminescent (PL) sensitivity is seen after sintering around 325°C. While the observed increase in TSL sensitivity (by 30%) with increasing sintering temperature in the range 325-700°C is explained on the basis of diffusion of Dy3+ ions from the surface to the whole volume of the grains (0-75 µm), the drastic decrease (by a factor of 3) in PL sensitivity with increasing sintering temperature is explained on the basis of change in the Dy3+ environment on the grain surface perhaps due to oxygen incorporation. Washing with water and acetone, which affect mainly the surface traps, enhances the PL sensitivity of CaSO4 : Dy slightly; however, it does not influence TSL sensitivity very significantly. Grinding reduces PL in general, but no such trend was noticed in TSL which supports the conclusion that PL originates mainly from surface traps since grinding affects mainly the grain surface. However, the sharp reduction in TSL and PL sensitivities observed at 400°C indicates that an unusual process takes place near that sintering temperature.
Exchange between perverse and weight filtration for the Hilbert schemes of points of two surfaces

We show that a natural isomorphism between the rational cohomology groups of the two zero-dimensional Hilbert schemes of $n$-points of two surfaces, the affine plane minus the axes and the cotangent bundle of an elliptic curve, exchanges the weight filtration on the first set of cohomology groups with the perverse Leray filtration associated with a natural fibration on the second set of cohomology groups. We discuss some associated hard Lefschetz phenomena.