Miracle-dz/UniFAR-FTUs huggingface dataset:
Absolute triple differential cross sections of electron impact ionisation of helium at 600 eV collision energy

Triple differential cross sections for electron impact ionisation of helium by 600 eV electrons have been measured and normalised to an absolute scale by extrapolating the generalised oscillator strength to zero momentum transfer. In this optical limit the triple differential cross sections can be expressed by the dipole transition matrix elements which are accurately known from photoionisation. The same cross sections have been calculated in the first Born approximation using quantum defect phaseshifts and standing-wave solutions for the ejected electron within a simple static potential approximation. Rather good agreement between this first-order theory and experiment is obtained for momentum transfer up to approximately 0.7 au, which contains a large fraction of all collisions leading to single ionisation. On the other hand, the experiments demonstrate the existence of higher-order effects for q>0.5 au, but a quantitative estimate of their importance for the calculation of triple differential cross sections is not yet possible.
Effect of a magnetic field on the magnetostructural phase transition inGd5(SixGe1−x)4

The first-order magnetostructural phase transition in Gd5(SixGe12x) 4 alloys with x<0.5 and the related entropy change DS are analyzed from high-field magnetization curves up to 23 T, and differential scanning calorimetry up to 5 T. The variation of the transition field Ht with the transition temperature Tt is discussed for fields up to 23 T for thex<0.5 range. From these data, the ratio dHt /dTt , which is related to the strength of the magnetoelastic coupling, is obtained as a function of x. We show that DS obtained from the ClausiusClapyeron equation and the Maxwell relation are equivalent for all compositions (0 <x<0.5), provided the Maxwell relation is evaluated only within the transition region. The T and H dependences of DS are accounted for by modeling the T and H dependences of the magnetization outside the transition.
Excitation of the ionospheric Alfvén resonator from the ground: Theory and experiments

[1] We report results from numerical and experimental studies of the excitation of ULF shear Alfven waves inside the ionospheric Alfven resonator (IAR) by heating the ionosphere with powerful HF waves launched from the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. Numerical simulations of the two-fluid MHD model describing IAR in a dipole magnetic field geometry with plasma parameters taken from the observations at HAARP during the October–November 2010 experimental campaign reveal that the IAR quality is higher during nighttime conditions, when the ionospheric conductivity is very low. Simulations also reveal that the resonance wave cannot be identified from the magnetic measurements on the ground or at an altitude above 600 km because the magnetic field in this wave has nodes on both ends of the resonator, and the best way to detect IAR modes is by measuring the electric field on low Earth orbit satellites. These theoretical predictions are in good, quantitative agreement with results from observations: In particular, (1) observations from the ground-based magnetometer at the HAARP site demonstrate no significant difference in the amplitudes of the magnetic field generated by HAARP in the frequency range from 0 to 5 Hz, and (2) the DEMETER satellite detected the electric field of the IAR first harmonic at an altitude of 670 km above HAARP during the heating experiment.
Some Exact Percentage Points of a Statistic Useful in Analysis of Variance and Principal Component Analysis

Some exact percentage points are given for the ratio of the largest eigenvalue to the trace of Z′Z, where Z is a matrix having independent standard normal variates as entries. These percentage points are useful in certain analysis of variance models for two-way cross-classilied data, for which only approximations have been given to date. They also have implications for principal component analysis.
Active and Star-forming Galaxies and Their Supernovae

To investigate the extent to which nuclear starbursts or other nuclear activity may be connected with enhanced star formation activity in the host galaxy, we perform a statistical investigation of supernovae (SNe) discovered in host galaxies from four samples: the Markarian galaxies sample, the Second Byurakan Survey (SBS) sample, the north Galactic pole (NGP) sample of active or star-forming galaxies, and the NGP sample of normal galaxies. Forty-seven SNe in 41 Mrk galaxies, 10 SNe in six SBS galaxies, 29 SNe in 26 NGP active or star-forming galaxies, and 29 SNe in 26 NGP normal galaxies have been studied. We find that the rate of SNe, particularly core-collapse (Types Ib/c and II) SNe, is higher in active or star-forming galaxies in comparison with normal galaxies. Active or star-forming host galaxies of SNe are generally of later morphological type and have lower luminosity and smaller linear size than normal host galaxies of SNe. The radial distribution of SNe in active and star-forming galaxies shows a higher concentration toward the center of the active host galaxy than is the case for normal host galaxies, and this effect is more pronounced for core-collapse SNe. Ib/c-type SNe have been discovered only in active and star-forming galaxies of our samples. About 78% of these SNe are associated with H II regions or are located very close to the nuclear regions of these active galaxies, which are in turn hosting AGNs or starburst nuclei. Besides these new results, our study also supports the conclusions of several other earlier papers. We find that Type Ia SNe occur in all galaxy types, whereas core-collapse SNe of Types Ib/c and II are found only in spiral and irregular galaxies. The radial distribution of Type Ib SNe in their host galaxies is more centrally concentrated than that of Type II and Ia SNe. The radial distances of Types Ib/c and II SNe, from the nuclei of their host galaxies, is larger for barred spiral hosts. Core-collapse SNe are concentrated in spiral arms and are often close to or in the H II regions, whereas Type Ia SNe show only a loose association with spiral arms and no clear association with H II regions.
EXPERIMENTS ON PHRASAL CHUNKING IN NLP USING EXPONENTIATED GRADIENT FOR STRUCTURED PREDICTION

Exponentiated Gradient (EG) updates were originally introduced in (Kivinen and Warmuth, 1997) in the context of online learning algorithms. EG updates were shown by (Collins et al., 2008) to provide fast batch and online algorithms for learning a max-margin classifier. They show that EG can converge quickly due to multiplicative updates, and that EG updates can be factored into tractable components for structured prediction tasks where the number of output labels is exponential in the size of the input. In this project, we implement EG for a Natural Language Processing structured prediction task of phrasal chunking (finding noun phrases, and other phrases in text) and we compare the performance of EG with other discriminative learning algorithms that have state of the art results on this task.
A Partial Differential Equation Arising in a 1D Model for the 3D Vorticity Equation

We continue the study of the one-dimensional model for the vorticity equation considered in [4]. The partial differential equation σ yt + σσ xy = σ x σ y + vσ yxx is deduced, which appears as a generalization of the Burgers' equation, with possibly some connection also to the K dV equation. Some properties of this equation are given and propagating solutions are found which are of soliton type, both with non-compact and compact support.
Gravity Waves from Fronts: Parameterization and Middle Atmosphere Response in a General Circulation Model

Current parameterizations of the gravity wave processes that are relevant to middle atmosphere general circulation modeling need to have specified somewhere in the lower atmosphere a number of characteristics of the gravity wave spectrum that arise from different possible gravity wave sources (i.e., the so-called gravity wave source spectrum). The aim of this study is to take into account in the specification of the gravity wave source spectrum a space and time modulation of the gravity wave wind variance and propagation direction associated with the occurrence of frontal systems. Given that fronts are poorly resolved at the truncations commonly used in middle atmosphere models (typically T21‐T42), first a method is devised to diagnose conditions that are considered to be the precursor of frontogenesis in a space and time-dependent low-resolution flow. This is achieved by evaluating horizontal isotherm compression due to flow deformation and convergence. Second, when particular conditions are satisfied, the precursor to frontogenesis is used as an indicator of subgridscale gravity wave emission in the model. Third, the wind variance and the propagation direction of the gravity waves at the source level are specified according to empirical evidences of frontal generation of gravity waves. The MAECHAM4 middle atmosphere response to this gravity wave forcing is presented. The study is restricted to fronts since they are thought to be one of the major nonstationary gravity wave sources in the extratropics, other gravity wave source mechanisms being left for later examination.
A Semi-Implicit Finite-Element Barotropic Model

Abstract A barotropic primitive equation model using the finite-element method of space discretization is presented. The semi-implicit method of time discretization is implemented by taking a suitable form of the governing equations. Finite-element forecasts are then compared with those from both finite-difference and spectral models. From the point of view of both efficiency and accuracy it is concluded that the finite-element method of space discretization appears to he viable for the practical problem of numerical weather prediction.
Effect of the Interphase Zone on the Bulk Modulus of a Particulate Composite

An exact solution is found for the problem of hydrostatic compression of an infinite body containing a spherical inclusion, with the elastic moduli varying with radius outside of the inclusion. This may represent an interphase zone in a composite, or the transition zone around an aggregate particle in concrete, for example. Both the shear and the bulk moduli are assumed to be equal to a constant term plus a powerlaw term that decays away from the inclusion. The method of Frobenius series is used to generate an exact solution for the displacements and stresses. The solution is then used to estimate the effective bulk modulus ofa material containing a random dispersion of these inclusions. The results demonstrate the manner in which a localized interphase zone around an inclusion may markedly affect both the stress concentrations at the interface, and the overall bulk modulus of the material.
New Insights on the Chemical Composition of the Siberian Air Shed From The Yak-Aerosib Aircraft Campaigns

There are very few large-scale observations of the chemical composition of the Siberian airshed. The Airborne Extensive Regional Observations in Siberia (YAKAEROSIB) French–Russian research program aims to fill this gap by collecting repeated aircraft high-precision measurements of the vertical distribution of CO2, CO, O3, and aerosol size distribution in the Siberian troposphere on a transect of 4,000 km during campaigns lasting approximately one week. This manuscript gives an overview of the results from five campaigns executed in April 2006, September 2006, August 2007, and early and late July 2008. The dense set of CO2 vertical profiles, consisting of some 50 profiles in each campaign, is shown to constrain large-scale models of CO2 synoptic transport, in particular frontal transport processes. The observed seasonal cycle of CO2 in altitude reduces uncertainty on the seasonal covariance between vegetation fluxes and vertical mixing, known as the “seasonal rectifier effect. ” Regarding carbon dioxide, w.
F-purity and rational singularity

We investigate singularities which are F-pure (respectively F-pure type). A ring R of characteristic p is F-pure if for every R-module M, 0 M ? R M ? 'R is exact where 1R denotes the R-algebra structure induced on R via the Frobenius map (if r E R and s E 1R, then r s = rPs in 1R). F-pure type is defined in characteristic 0 by reducing to characteristicp. It is proven that when R = S/I is the quotient of a regular local ring S, R is F-pure at the prime ideal Q if and only if (I[PI: I) ? Q[P]. Here, J[P] denotes the ideal {aP I a E J}. Several theorems result from this criterion. If f is a quasihomogeneous hypersurface having weights (r1,.,r) and an isolated singularity at the origin: (1) 17 1ri > I implies K[X1,. X]/(f) has F-pure type at m = (X1,. X). (2) 1n I ri < I implies K [ X1 . Xn ]/(f) does not have F-pure type at m. (3) 1%= 1ri = I remains unsolved, but does connect with a problem that number theorists have studied for many years. This theorem parallels known results about rational singularities. It is also proven that classifying F-pure singularities for complete intersection ideals can be reduced to classifying such singularities for hypersurfaces, and that the F-pure locus in the maximal spectrum of K [ X1, . Xn ]/I, where K is a perfect field of characteristic P, is Zariski open. An important conjecture is that R/fR is F-pure (type) should imply R is F-pure (type) whenever R is a Cohen-Macauley, normal local ring. It is proven that Ext1( 1R, R) = 0 is a sufficient, though not necessary, condition. A local ring (R, m) of characteristic p is F-injective if the Frobenius map induces an injection on the local cohomology modules H' (R) H' (1R). An example is constructed which is F-injective but not F-pure. From this a counterexample to the conjecture that R/fR is F-pure implies R is F-pure is constructed. However, it is not a domain, much less normal. Moreover, it does not lead to a counterexample to the characteristic 0 version of the conjecture. 0. Introduction. Let R be a ring of characteristic p and let 'R denote the ring R viewed as an R-module via the Frobenius map F(r) = rP. R is F-pure if for every R-module M, 0 -R ? M -4'R ? M is exact. A notion of F-pure type is then defined in characteristic 0 by reduction to characteristicp. F-pure rings are connected with invariant theory and appear in the proof that the ring of invariants of a linearly reductive affine linear group acting on a regular ring is Cohen-Macaulay [3]. It has also been demonstrated that F-purity measures good singularities in the sense that it implies a great deal of simplification in the computation of local cohomology [1]. Received by the editors March 30, 1982 and, in revised form, August 3, 1982. 1980 Mathematics Subject Classification. Primary 13H99. 1983 American Mathematical Society 0002-9947/82/0000-0829/$05.25
Sums of incompressible surfaces

In an orientable Haken 3-manifold, given two orientable incompressible surfaces F and S transverse to each other with intersections suitably simplified, certain cut-and-paste operations along curves of intersection yield embedded incompressible surfaces. We show in this paper that, no matter how F and S axe isotoped, as long as intersections axe suitably simplified, exactly the same finite (possibly empty) set of isotopy classes of incompressible surfaces result from cut-and-paste operations. 0. Introduction and statement of results. Throughout this paper we let M be an irreducible, a-irreducible, orientable 3-manifold. Given two incompressible surfaces F and S, transverse to each other and with simplified intersection, it is possible to cut F and S on curves of intersection and reglue (in different ways) to obtain a properly embedded surface, G say. This operation is traditionally called a cut-and-paste operation. Often, depending on choices, G will not be incompressible. We study in this paper those cut-and-paste operations which do yield incompressible surfaces. We address the following: QUESTION 0. Suppose F and S are orientable incompressible surfaces intersecting transver8ly. Suppose F' and S' are isotopic to F and S respectively. Finally, suppose F' and S' also intersect transversely. If an incompressible surface G is obtained from F and S by a cut-and-paste operation, can a surface isotopic to G be obtained from F' and S' by cut-and-paste? We shall see that we cannot hope for a positive answer to the question without imposing conditions on the intersection of F and S (F' and S'). Suppose F, S are orientable incompressible, a-incompressible surfaces in M. If F n s contains contractible closed curves, we can eliminate them by isotopy of F or S. Similarly, if F n s contains arcs which are isotopic in F or S to an arc in aF or AS, these can be eliminated by isotopy. For simplicity, we call these arcs contractible curves also. If a is an arc, we use R = (a x I)/ to denote a product with x x I collapsed to a point for each x E aa. Given such a product embedded in AM with a x 1 C aF, a x 0 C AS, and R n (S U F) = AR, we can isotope (F, aF) or (S, AS) in (M, AM) to eliminate two intersections of aF and AS. Similarly, if W is a compact surface with boundary and -y is a closed 1-submanifold of aW, we use Received by the editors September 8, 1986 and, in revised form, November 10, 1986. This paper was presented at an AMS meeting in Los Angeles, November 14, 1987. 1980 Mathematic8 Subject Classification (1985 Revtiion). Primary 57M99; Secondary 57R52.
Constructing the Spatial Weights Matrix Using a Local Statistic

Spatial weights matrices are necessary elements in most regression models where a representation of spatial structure is needed. We construct a spatial weights matrix, W, based on the principle that spatial structure should be considered in a two-part framework, those units that evoke a distance effect, and those that do not. Our twovariable local statistics model (LSM) is based on the Gi* local statistic. The local statistic concept depends on the designation of a critical distance, dc, defined as the distance beyond which no discernible increase in clustering of high or low values exists. In a series of simulation experiments LSM is compared to well-known spatial weights matrix specifications—two different contiguity configurations, three different inverse distance formulations, and three semi-variance models. The simulation experiments are carried out on a random spatial pattern and two types of spatial clustering patterns. The LSM performed best according to the Akaike Information Criterion, a spatial autoregressive coefficient evaluation, and Moran's I tests on residuals. The flexibility inherent in the LSM allows for its favorable performance when compared to the rigidity of the global models.
Effect of Aspect Ratio on the Three-Dimensional Global Instability Analysis of Incompressible Open Cavity Flows

The stability analysis of open cavity flows is a problem of great interest in the aeronautical industry. This type of flow can appear, for example, in landing gears or auxiliary power unit configurations. Open cavity flows is very sensitive to any change in the configuration, either physical (incoming boundary layer, Reynolds or Mach numbers) or geometrical (length to depth and length to width ratio). In this work, we have focused on the eect of geometry and of the Reynolds number on the stability properties of a three- dimensional spanwise periodic cavity flow in the incompressible limit. To that end, BiGlobal analysis is used to investigate the instabilities in this configuration. The basic flow is obtained by the numerical integration of the Navier-Stokes equations with laminar boundary layers imposed upstream. The 3D perturbation, assumed to be periodic in the spanwise direction, is obtained as the solution of the global eigenvalue problem. A parametric study has been performed, analyzing the stability of the flow under variation of the Reynolds number, the L/D ratio of the cavity, and the spanwise wavenumber . For consistency, multidomain high order numerical schemes have been used in all the computations, either basic flow or eigenvalue problems. The results allow to define the neutral curves in the range of L/D = 1 to L/D = 3. A scaling relating the frequency of the eigenmodes and the length to depth ratio is provided, based on the analysis results.
One-Dimensional Transient Radiative Transfer in Complex Semitransparent Medium by Meshless Method

A diffuse approximation meshless method based on the discrete ordinates equation is presented to solve transient radiative transfer problems, and the transient term is discretized by employing the fully implicit scheme. We consider transient radiative heat transfer problems in both homogeneous (constant refractive index, in this case n=1.0) and graded-index media bounded by a slab. Results obtained using the proposed meshless method are compared with published results to demonstrate the flexibility and accuracy of the method. In some cases, such as a step-shaped pulse boundary condition, the diffuse approximation meshless method presents false diffusion characteristics, but apart from these types of cases, the proposed diffuse approximation meshless method could be used to solve transient radiative transfer problems in homogeneous and graded-index media with sufficient spatial and angular discretizations.
The slowly declining type Ia supernova 2008fv and the near-infrared second maximum

Aims. We present optical and near-infrared (NIR) photometry of supernova (SN) 2008fv and a brief investigation of SN type Ia to search for possible correlations between the properties of NIR light curves and the optical decline rate. Methods. We analyse our BVRI and JHK observations to derive light curves (LCs), colour curves, and the bolometric behaviour of SN2008fv. Data range from about five days before to two months after maximum. We also collect a database of the main characteristics of NIR LCs of SNeIa available in literature. Results. We find close similarities between the observed LCs of the SN event studied here and SN 2000E. SN 2008fv is a slow-declining SNeIa with a post-maximum decline of Δm15,B = 0.96 ± 0.08 mag and a B-band maximum luminosity of MB,0 = −19.40 ± 0.1 mag, close to the value of normal SNeIa. The optical and NIR data allow us to constrain the host galaxy reddening of NGC 3147, E(B−V) = 0.22 ± 0.05 mag and its distance μ = 33.2 ± 0.1 mag. Furthermore, we derive a synthesized 56 Ni mass of about 0.7 M� , by using the well-known relation between the maximum luminosity of the uvoir bolometric light curve and the initial content of 56 Ni. We investigate the correlation between the NIR characteristics of LCs and optical properties by collecting data of a sample of 40 SNe. We derive quantitative relationships involving the epoch of the secondary maximum in the JHK bands and the decline rate Δm15(B). Further, we find no correlations between Δm15 measured in the JHK bands and the optical Δm15(B). In contrast, quite evident correlations with the Δm15(B )a ndΔm40(J)/Δm15(H).
COMPARISON OF NATURAL FREQUENCIES OF LAMINATES BY 3-D THEORY, PART I: RECTANGULAR PLATES

Abstract The three-dimensional theory of laminated plates and shells has been developed by Chao et al.[10–13, 62, 63] with many applications to impact and shock modal analyses. In this research, a complete survey of the literature is made on the free vibration natural frequencies of simply supported rectangular plates. Various boundary conditions are composed of fixed pin, hinge-roller, and sliding pin supported edges. The lowest frequencies are obtained in the present study in comparison with those in earlier studies as a result of the close natural state reached in keeping with the three-dimensional boundary and interlaminar continuity conditions via a 3-D augmented energy variational approach.