Miracle-dz/UniFAR-FTUs huggingface dataset:
The HARPS search for southern extra-solar planets. X. A m sin i = 11 M_â planet around the nearby spotted M dwarf GJ 674

Context. How planet properties depend on stellar mass is a key diagnostic of planetary formation mechanisms. Aims. This motivates planet searches around stars that are significantly more massive or less massive than the Sun, and in particular our radial velocity search for planets around very low-mass stars. Methods. As part of that program, we obtained measurements of GJ 674, an M 2.5 dwarf at d = 4.5 pc. These measurements have dispersion much in excess of their internal errors. An intensive observing campaign demonstrates that the excess dispersion is due to two superimposed coherent signals, with periods of 4.69 and 35 days. Results. These data are described well by a 2-planet Keplerian model where each planet has a ∼11 M⊕ minimum mass. A careful analysis of the (low-level) magnetic activity of GJ 674, however, demonstrates that the 35-day period coincides with the stellar rotation period. This signal therefore originates in a spot inhomogeneity modulated by stellar rotation. The 4.69-day signal, on the other hand, is caused by a bona-fide planet, GJ 674b. Conclusions. Its detection adds to the growing number of Neptune-mass planets around M-dwarfs and reinforces the emerging conclusion that this mass domain is much more populated than the Jovian mass range. We discuss the metallicity distributions of Md warfwith and without planets and find a low 11% probability that they are drawn from the same parent distribution. Moreover, we find tentative evidence that the host star metallicity correlates with the total mass of their planetary system.
Random Walks and Electric Networks: REFERENCES

Probability theory, like much of mathematics, is indebted to physics as a source of problems and intuition for solving these problems. Unfortunately, the level of abstraction of current mathematics often makes it difficult for anyone but an expert to appreciate this fact. In this work we will look at the interplay of physics and mathematics in terms of an example where the mathematics involved is at the college level. The example is the relation between elementary electric network theory and random walks. Central to the work will be Polya’s beautiful theorem that a random walker on an infinite street network in d-dimensional space is bound to return to the starting point when d = 2, but has a positive probability of escaping to infinity without returning to the starting point when d ≥ 3. Our goal will be to interpret this theorem as a statement about electric networks, and then to prove the theorem using techniques from classical electrical theory. The techniques referred to go back to Lord Rayleigh, who introduced them in connection with an investigation of musical instruments. The analog of Polya’s theorem in this connection is that wind instruments are possible in our three-dimensional world, but are not possible in Flatland (Abbott [1]). The connection between random walks and electric networks has been recognized for some time (see Kakutani [12], Kemeny, Snell, and
Air Entrainment by Bow Waves

Experimental studies of air entrainment by breaking waves are essential for advancing the understanding of these flows and creating valid models. The present study used three-dimensional simulations of a bow wave to examine its air entrainment process. The simulated waves were created by a deflecting plate mounted at an angle in a super-critical free surface flow. Since the air entrainment process is closely coupled with breaking wave dynamics, the present study included both air entrainment and free surface measurements. Measurements of the free surface were obtained from the simulated bow waves at two scales, and also from the bow wave created by a towed wedge model. Contact line and bow wave profile measurements for the different experiments were compared, demonstrating the similarity of the experimental simulations to the towed model experiments. The plunging wave jet shape was measured in the larger scale stationary model and towed model experiments and used to calculate jet thickness, velocity, and impingement angle. The bow wave profile data from the towed model experiments were used to investigate the scaling of the wave with the flow and geometric parameters. Surface disturbances were observed on the plunging wave face, and their wavelength, frequency, and velocity were measured. The primary mechanisms for air entrainment were the impact of the plunging wave jet and individual droplets in the splash region on the free surface. The air entrainment process was observed in the larger scale stationary model experiments, and the air bubbles were entrained in spatially periodic bubble clouds. Due to the shallow depth in these experiments, measurements of only the larger bubbles in the initial stages of air entrainment were obtained. An impedance based void fraction meter, developed specifically for the purpose, was used to measure void fractions and bubble size distributions beneath the wave. The bubble cloud size and void fraction increased with downstream distance. There were indications that the surface disturbances control the periodicity of the bubble clouds. Namely, the surface disturbances divide the plunging liquid jet sheet into a series of plunging wave jets, each entraining air into a separate bubble cloud beneath the free surface.
Symbolic Dynamics for the Geodesic Flow on Two-dimensional Hyperbolic Good Orbifolds

We construct cross sections for the geodesic flow on the orbifolds $\Gamma\backslash H$ which are tailor-made for the requirements of transfer operator approaches to Maass cusp forms and Selberg zeta functions. Here, $H$ denotes the hyperbolic plane and $\Gamma$ is a nonuniform geometrically finite Fuchsian group (not necessarily a lattice, not necessarily arithmetic) which satisfies an additional condition of geometric nature. The construction of the cross sections is uniform, geometric, explicit and algorithmic.
The Hilbert schemes of locally Cohen-Macaulay curves in P^3 may after all be connected

Progress on the problem whether the Hilbert schemes of locally Cohen-Macaulay curves in projective 3 space are connected has been hampered by the lack of an answer to a question that was raised by Robin Hartshorne in his paper "On the connectedness of the Hilbert scheme of curves in projective 3 space" Comm. Algebra 28 (2000) and more recently in the open problems list of the 2010 AIM workshop Components of Hilbert Schemes available at this http URL does there exist a flat irreducible family of curves whose general member is a union of d disjoint lines on a smooth quadric surface and whose special member is a locally Cohen-Macaulay curve in a double plane? In this paper we give a positive answer to this question: for every d, we construct a family with the required properties, whose special fiber is an extremal curve in the sense of Martin-Deschamps and Perrin. From this we conclude that every effective divisor in a smooth quadric surface is in the connected component of its Hilbert scheme that contains extremal curves.
Existence of Smooth Solutions to Coupled Chemotaxis-Fluid Equations

We consider a system coupling the parabolic-parabolic Keller-Segel equations to the in- compressible Navier-Stokes equations in spatial dimensions two and three. We establish the local existence of regular solutions and present some blow-up criteria. For two dimensional Navier-Stokes-Keller-Segel equations, regular solutions constructed locally in time are, in reality, extended globally under some assumptions pertinent to experimental observation in [20] on the consumption rate and chemotactic sensitivity. We also show the existence of global weak solutions in spatially three dimensions with rather restrictive consumption rate and chemotactic sensitivity.
Classification of resolving subcategories and grade consistent functions

We classify certain resolving subcategories of finitely generated modules over a commutative noetherian ring R by using integer-valued functions on Spec R. As an application we give a complete classification of resolving subcategories when R is a locally hypersurface ring. Our results also recover a "missing theorem" by Auslander.
Elaboration de revêtements sur acier inoxydable: simulation de la fusion par irradiation laser, caractérisation structurale, mécanique et tribologique.

L'irradiation par un laser Nd-YAG pulse est mise en oeuvre afin d'elaborer des revetements epais sur acier inoxydable X30Cr13, par fusion superficielle avec apport de bore ou nitrure de bore hexagonal (h-BN): alliages borures polyphases ou composites metal-ceramique. Les coupes metallographiques permettent de determiner l'epaisseur de chaque revetement (zone fondue) et revelent des microstructures de solidification caracteristiques: front plan, cellulaire et dendritique. Les caracteristiques optiques du faisceau laser sont determinees: divergence, distance focale, rayon du spot et distribution de la puissance dans le plan focal. La simulation des effets thermiques est fondee sur la modelisation par differences finies de la distribution spatio-temporelle de la temperature, dans l'acier irradie par balayage du faisceau pulse. Par ce moyen, la prevision de l'epaisseur atteinte par la zone fondue et la description de l'avancement du front de fusion durant l'irradiation deviennent possibles, d'ou une meilleure description des conditions d'incorporation de matiere, selon un processus de fusions et solidifications successives. Les proprietes mecaniques, module d'elasticite et durete, des divers revetements sont determinees a partir d'essais de nanoindentation. Dans des conditions d'irradiation optimales, la durete du composite atteint 10 GPa et celle de l'alliage borure, 14 GPa, alors que l'acier non traite a une durete de 4 GPa. L'analyse systematique du comportement tribologique des revetements est effectuee en configuration bille-sur-disque, a 25 °C sous differentes charges (1 a 10 N), puis a 300 et 500 °C sous 2 N. A temperature ambiante, le glissement a sec sur bille en rubis de ces deux types de revetements est caracterise par un coefficient de frottement reduit et un faible taux d'usure volumique, par rapport a ceux de l'acier non traite, revelant une resistance nettement renforcee envers l'usure adhesive et/ou abrasive. A partir de 300 °C, en revanche, leur tenue au frottement se degrade, malgre l'abaissement sensible du coefficient de frottement.
Strong quasiconvexity, stability, and lower relative divergence in right-angled Artin groups

Let $\Gamma$ be a simplicial, finite, connected graph such that $\Gamma$ does not decompose as a nontrivial join. We prove that two notions of strong quasiconvexity and stability are equivalent in the right-angled Artin group $A_\Gamma$ (except for the case of finite index subgroups). We also characterize non-trivial strongly quasiconvex subgroups of infinite index in $A_\Gamma$ (i.e. non-trivial stable subgroups in $A_\Gamma$) by quadratic lower relative divergence. These results strengthen the work of Koberda-Mangahas-Taylor on characterizing purely loxodromic subgroups of right-angled Artin groups.
Data Visualization using Spline Functions

A two parameter family of C1 rational cubic spline functions is presented for the graphical representation of shape preserving curve interpolation for shaped data. These parameters have a direct impact on the shape of the curve. Constraints are developed on one family of the parameters to visualize positive, monotone and convex data while other family of parameters can assume any positive values. The problem of visualization of constrained data is also addressed when the data is lying above a straight line and curve is required to lie on the same side of the line. The approximation order of the proposed rational cubic function is also investigated and is found to be O(h3) .
Fisher–KPP propagation in the presence of a line: further effects

This paper is a continuation of Berestycki et al (2013 J. Math. Biol. 66 743–66) where a new model of biological invasions in the plane directed by a line was introduced. Here we include new features such as transport and reaction terms on the line. Their interaction with the pure diffusivity in the plane is quantified in terms of enhancement of the propagation speed. We establish conditions that determine whether the spreading speed exceeds the standard Fisher–KPP invasion speed. These conditions involve the ratio of the diffusivities on the line and in the field, the transport term and the reactions. We derive the asymptotic behaviour for large diffusions or large transports. We also discuss the biological interpretation of these findings.
Finiteness of commutable maps of bounded degree

In this paper, we study the relation between two dynamical systems (V,f) and (V,g) with f. g = g . f. As an application, we show that an endomorphism (respectively a polynomial map with Zariski dense, of bounded Pre(f) has only finitely many endomorphisms (respectively polynomial maps) of bounded degree which are commutable with f.
Type Algebras, Functor Categories, and Block Structure

In this paper we outline a category-theoretic approach to the semantics of ALGOL-like languages in which particular attention is paid to the use of functor categories as a mechanism to reflect stack discipline. Also, we explore the idea that implicit conversions can be modelled by making the phrase types of a language into a poset, and we show how any poset freely generates a type algebra.
Tracking and Almost Disturbance Decoupling for Nonlinear Systems with Uncertainties

This paper studies the output tracking and almost disturbance decoupling problem of nonlinear control systems with uncertainties. The main contribution of this study is to construct a controller, under appropriate conditions, such that the resulting closed-loop system is valid for any initial condition and bounded tracking signal with the following characteristics: input-to-state stability with respect to disturbance inputs and almost disturbance decoupling, i. e. , the influence of disturbances on the L2 norm of the output tracking error can be arbitrarily attenuated by changing some adjustable parameters. The fundamental theoretical approaches are the differential geometry approach and the composite Lyapunov approach. Two examples, which cannot be solved by the first paper on the almost disturbance decoupling problem, are proposed in this paper to exploit the fact that the tracking and the almost disturbance decoupling performances are easily achieved by the proposed approach. In order to demonstrate the practical applicability, the paper has investigated a pendulum control system that cannot be solved by some existent approaches.
Outer scale of turbulence: comparison of different models

The calculation results obtained with different outer-scale dependent atmospheric turbulence models are presented. Three outer-scale models are considered: the exponential model, the von Karman model, and the Greenwood model. A generalization of the outer-scale models is suggested. The calculation results of the refractive-index structure functions and of the structure functions of phase and spatial–temporal Zernike coefficient characteristics are compared for the cases of different outer-scale models. In the case of Kolmogorov turbulence the analytical expressions for the temporal correlation functions and spectra of the Zernike coefficients are obtained. It is shown that all considered models give nearly the same results.
Planar waveguide with “twisted” boundary conditions: Discrete spectrum

We consider a planar waveguide with combined Dirichlet and Neumann conditions imposed in a “twisted” way. We study the discrete spectrum and describe it dependence on the configuration of the boundary conditions. In particular, we show that in certain cases the model can have discrete eigenvalues emerging from the threshold of the essential spectrum. We give a criterium for their existence and construct them as convergent holomorphic series.
Homological and homotopical Dehn functions are different

The homological and homotopical Dehn functions are different ways of measuring the difficulty of filling a closed curve inside a group or a space. The homological Dehn function measures fillings of cycles by chains, whereas the homotopical Dehn function measures fillings of curves by disks. Because the two definitions involve different sorts of boundaries and fillings, there is no a priori relationship between the two functions; however, before this work, there were no known examples of finitely presented groups for which the two functions differ. This paper gives such examples, constructed by amalgamating a free-by-cyclic group with several Bestvina–Brady groups.
Effects of mathematical locality and number scaling on coordinate chart use

A stronger foundation for earlier work on the effects of number scaling, and local mathematics is described. Emphasis is placed on the effects of scaling on coordinate systems. Effects of scaling are represented by a scalar field, θ, that appears in gauge theories as a spin zero boson. Gauge theory considerations led to the concept of local mathematics, as expressed through the use of universes, ∪ x, as collections of local mathematical systems at each point, x, of a space time manifold, M. Both local and global coordinate charts are described. These map M into either local or global coordinate systems within a universe or between universes, respectively. The lifting of global expressions of nonlocal physical quantities, expressed by space and or time integrals or derivatives on M, to integrals or derivatives on coordinate systems, is described. The assumption of local mathematics and universes makes integrals and derivatives, on M or on global charts, meaningless. They acquire meaning only when mapped into a local universe. The effect of scaling, by including the effect of θ into the local maps, is described. The lack of experimental evidence for θ so far shows that the coupling constant of θ to matter fields must be very small compared to the fine structure constant. Also the gradient of θ must be very small in the local region of cosmological space and time occupied by us as observers. So far, there are no known restrictions on θ or its gradient in regions of space and/or time that are far away from our local region.
Technetium and lithium in Galactic bulge AGB stars

1 Institute for Astronomy, University of Vienna, Turkenschanzstrase 17, 1180 Vienna, Austria e-mail: [uttenthaler;hron;lebzelter;lederer;aringer]@astro.univie. ac.at 2 Department of Physics, University of Perugia, via A. Pascoli 1, 06123 Perugia, Italy e-mail: [busso;palmerini]@fisica.unipg. it 3 Observatoire de Besancon, 41bis, avenue de l’Observatoire, BP 1615, 25010 Besancon Cedex, France e-mail: mathias@obs-besancon.fr 4 European Southern Observatory, Karl Schwarzschild Strase 2, 85748 Garching near Munich, Germany e-mail: hukaufl@eso.org
Thirty-five years and counting

It has been 35 years since Stanley proved that f-vectors of boundaries of simplicial polytopes satisfy McMullen's conjectured g-conditions. Since then one of the outstanding questions in the realm of face enumeration is whether or not Stanley's proof could be extended to larger classes of spheres. Here we hope to give an overview of various attempts to accomplish this and why we feel this is so important. In particular, we will see a strong connection to f-vectors of manifolds and pseudomanifolds. Along the way we have included several previously unpublished results involving how the g-conjecture relates to bistellar moves and small g_2, the topology and combinatorics of stacked manifolds introduced independently by Bagchi and Datta, and Murai and Nevo, and counterexamples to over optimistic generalizations of the g-theorem.
ALGEBRAIC FIBER SPACES AND CURVATURE OF HIGHER DIRECT IMAGES

Abstract Let $p:X\rightarrow Y$ be an algebraic fiber space, and let $L$ be a line bundle on $X$ . In this article, we obtain a curvature formula for the higher direct images of $\unicode[STIX]{x1D6FA}_{X/Y}^{i}\otimes L$ restricted to a suitable Zariski open subset of $X$ . Our results are particularly meaningful if $L$ is semi-negatively curved on $X$ and strictly negative or trivial on smooth fibers of $p$ . Several applications are obtained, including a new proof of a result by Viehweg–Zuo in the context of a canonically polarized family of maximal variation and its version for Calabi–Yau families. The main feature of our approach is that the general curvature formulas we obtain allow us to bypass the use of ramified covers – and the complications that are induced by them.
An efficient and flexible approach to the calculation of three-dimensional full-wave Fréchet kernels for seismic tomography—I. Theory

SUMMARY We propose a new approach to computing the sensitivity kernels used in seismic tomography based on a Green's function database. For any perturbation in the Earth's structural model, the waveform Frechet derivative can be expressed in terms of strain Green's tensors, which are themselves functions of the reference Earth model only. The Frechet derivative of any seismic observable can then be obtained from waveform Frechet derivative. Given a reference model, a strain Green's tensor database can be established, thus eliminating the need for repetitive wavefield evaluations in all subsequent synthetic and kernel calculations, and reducing the CPU time. For a spherically symmetric reference Earth model, the strain Green's tensor database can be constructed on a (r, Δ) grid by normal-mode summation. The stored strain Green's tensors can then be used to quickly evaluate the wavefield between any source and receiver. The generality of the strain Green's tensors makes it possible to compute the Frechet kernels for any phase on a seismogram (P, S, Pdiff, surface waves, etc.), for any type of data (traveltime, amplitude, splitting intensity, waveform, etc.), and for any parameter (isotropic, anisotropic, attenuation, etc.). The kernel calculation at each point in the medium is reduced to the convolution of two sets of strain Green's tensors extracted from the database, which makes the approach extremely efficient.
Bounded gaps between product of two primes in number fields

We combine the methods of Goldston-Graham-Pintz-Y\i ld\i r\i m \cite{GGPY} and Maynard~-Tao~\cite{MAY} to study bounded gaps between product of two primes in imaginary quadratic fields of class number one. In particular, we show that for $K_d=\mathbb{Q}\left(\sqrt d\right), d=-1, -2, -3, -7, -11, -19, -43, -67 \text{ and } -163,$ there exist infinitely many pairs $\alpha_1, \alpha_2$ which are product of two prime elements in $K_d$ such that $|\sigma(\alpha_1-\alpha_2)|\leq 2$ for all embeddings $\sigma$ of $K_d. $
Asymmetric Latin squares, Steiner triple systems, and edge-parallelisms

This article, showing that almost all objects in the title are asymmetric, is re-typed from a manuscript I wrote somewhere around 1980 (after the papers of Bang and Friedland on the permanent conjecture but before those of Egorychev and Falikman). I am not sure of the exact date. The manuscript had been lost, but surfaced among my papers recently. I am grateful to Laci Babai and Ian Wanless who have encouraged me to make this document public, and to Ian for spotting a couple of typos. In the section on Latin squares, Ian objects to my use of the term "cell"; this might be more reasonably called a "triple" (since it specifies a row, column and symbol), but I have decided to keep the terminology I originally used. The result for Latin squares is in B. D. McKay and I. M. Wanless, On the number of Latin squares, Annals of Combinatorics 9 (2005), 335-344 (arXiv 0909.2101), while the result for Steiner triple systems is in L. Babai, Almost all Steiner triple systems are asymmetric, Annals of Discrete Mathematics 7 (1980), 37-39.