WorldWideScience

Sample records for walkers facts conjectures

  1. Statement of Facts for 1977 City-Wide Mock Trial Competitions. Walker Thomas v. Sam Nomad.

    Science.gov (United States)

    National Inst. for Citizen Education in the Law, Washington, DC.

    Prepared by the District of Columbia Street Law Project for its annual city-wide mock trial competition, this instructional handout provides material for a civil case over an automobile accident. Walker Thomas is suing Sam Nomad for damages that resulted from a collision, for which both parties blame the other. The handout clarifies the laws and…

  2. Lang's Height Conjecture and Szpiro's Conjecture

    CERN Document Server

    Silverman, Joseph H

    2009-01-01

    It is known that Szpiro's conjecture, or equivalently the ABC-conjecture, implies Lang's conjecture giving a uniform lower bound for the canonical height of nontorsion points on elliptic curves. In this note we show that a significantly weaker version of Szpiro's conjecture, which we call "prime-depleted," suffices to prove Lang's conjecture.

  3. Three friendly walkers

    Science.gov (United States)

    Jensen, Iwan

    2017-01-01

    More than 15 years ago Guttmann and Vöge (2002 J. Stat. Plan. Inference 101 107), introduced a model of friendly walkers. Since then it has remained unsolved. In this paper we provide the exact solution to a closely allied model which essentially only differs in the boundary conditions. The exact solution is expressed in terms of the reciprocal of the generating function for vicious walkers which is a D-finite function. However, ratios of D-finite functions are inherently not D-finite and in this case we prove that the friendly walkers generating function is the solution to a non-linear differential equation with polynomial coefficients, it is in other words D-algebraic. We find using numerically exact calculations a conjectured expression for the generating function of the original model as a ratio of a D-finite function and the generating function for vicious walkers. We obtain an expression for this D-finite function in terms of a {{}2}{{F}1} hypergeometric function with a rational pullback and its first and second derivatives. Dedicated to Tony Guttmann on the occasion of his 70th birthday.

  4. The Multiplicity Conjecture in low codimensions

    OpenAIRE

    2004-01-01

    We establish the multiplicity conjecture of Herzog, Huneke, and Srinivasan about the multiplicity of graded Cohen-Macaulay algebras over a field, for codimension two algebras and for Gorenstein algebras of codimension three. In fact, we prove stronger bounds than the conjectured ones allowing us to characterize the extremal cases. This may be seen as a converse to the multiplicity formula of Huneke and Miller that inspired the conjectural bounds.

  5. Lang's conjectures, conjecture H, and uniformity

    CERN Document Server

    Abramovich, D

    1995-01-01

    The purpose of this note is to wish a happy birthday to Professor Lucia Caporaso.* We prove that Conjecture H of Caporaso et. al. ([CHarM], sec. 6) together with Lang's conjecture implies the uniformity of rational points on varieties of general type, as predicted in [CHarM]; a few applications in arithmetic and geometry are stated. Let X be a variety of general type defined over a number field K. It was conjectured by S. Lang that the set of rational points X(K) is not Zariski dense in X. In the paper [CHarM] of L. Caporaso, J. Harris and B. Mazur it is shown that the above conjecture of Lang implies the existence of a uniform bound on the number of K-rational points of all curves of fixed genus g over K. The paper [CHarM] has immediately created a chasm among arithmetic geometers. This chasm, which often runs right in the middle of the personalities involved, divides between loyal believers of Lang's conjecture, who marvel in this powerful implication, and the disbelievers, who try (so far in vain) to use t...

  6. The Bieberbach conjecture

    CERN Document Server

    Gong, Sheng

    2014-01-01

    In 1919, Bieberbach posed a seemingly simple conjecture. That "simple" conjecture challenged mathematicians in complex analysis for the following 68 years! In that time, a huge number of papers discussing the conjecture and its related problems were inspired. Finally in 1984, de Branges completed the solution. In 1989, Professor Gong wrote and published a short book in Chinese, The Bieberbach Conjecture, outlining the history of the related problems and de Branges' proof. The present volume is the English translation of that Chinese edition with modifications by the author. In particular, he includes results related to several complex variables. Open problems and a large number of new mathematical results motivated by the Bieberbach conjecture are included. Completion of a standard one-year graduate complex analysis course will prepare the reader for understanding the book. It would make a nice supplementary text for a topics course at the advanced undergraduate or graduate level.

  7. Neimark-Sacker bifurcations and evidence of chaos in a discrete dynamical model of walkers

    Science.gov (United States)

    Rahman, Aminur; Blackmore, Denis

    2016-10-01

    Bouncing droplets on a vibrating fluid bath can exhibit wave-particle behavior, such as being propelled by interacting with its own wave field. These droplets seem to walk across the bath, and thus are dubbed walkers. Experiments have shown that walkers can exhibit exotic dynamical behavior indicative of chaos. While the integro-differential models developed for these systems agree well with the experiments, they are difficult to analyze mathematically. In recent years, simpler discrete dynamical models have been derived and studied numerically. The numerical simulations of these models show evidence of exotic dynamics such as period doubling bifurcations, Neimark--Sacker (N--S) bifurcations, and even chaos. For example, in [Gilet, PRE 2014], based on simulations Gilet conjectured the existence of a supercritical N-S bifurcation as the damping factor in his one-dimensional path model. We prove Gilet's conjecture and more; in fact, both supercritical and subcritical (N-S) bifurcations are produced by separately varying the damping factor and wave-particle coupling for all eigenmode shapes. Then we compare our theoretical results with some previous and new numerical simulations, and find complete qualitative agreement. Furthermore, evidence of chaos is shown by numerically studying a global bifurcation.

  8. On Dirac's Conjecture

    Institute of Scientific and Technical Information of China (English)

    LI Zi-Ping; LI Ai-Min; JIANG Jin-Huan; WANG Yong-Long

    2005-01-01

    The extended canonical Noether identities and canonical first Noether theorem derived from an extended action in phase space for a system with a singular Lagrangian are formulated. Using these canonical Noether identities,it can be shown that the constraint multipliers connected with the first-class constraints may not be independent, so a query to a conjecture of Dirac is presented. Based on the symmetry properties of the constrained Hamiltonian system in phase space, a counterexample to a conjecture of Dirac is given to show that Dirac's conjecture fails in such a system.We present here a different way rather than Cawley's examples and other's ones in that there is no linearization of constraints in the problem. This example has a feature that neither the primary first-class constraints nor secondary first-class constraints are generators of the gauge transformation.

  9. On the Firoozbakht's conjecture

    OpenAIRE

    Sabihi, Ahmad

    2016-01-01

    This paper proves Firoozbakht's conjecture using Rosser and Schoenfelds' inequality on the distribution of primes. This inequality is valid for all natural numbers ${n\\geq 21}$. Firoozbakht's conjecture states that if $ {p_{n}}$ and ${p_{(n+1)}}$ are consecutive prime numbers, then ${p_{(n+1)}^{1/(n+1)}< p_{n}^{1/n}}$ for every ${n\\geq 1}$. Rosser's inequality for the ${n}$th and ${(n+1)}$th roots, changes from strictly increasing to strictly decreasing for ${n\\geq 21}$. The inequality is con...

  10. On the Firoozbakht's conjecture

    OpenAIRE

    Sabihi, Ahmad

    2016-01-01

    This paper proves Firoozbakht's conjecture using Rosser and Schoenfelds' inequality on the distribution of primes. This inequality is valid for all natural numbers ${n\\geq 21}$. Firoozbakht's conjecture states that if $ {p_{n}}$ and ${p_{(n+1)}}$ are consecutive prime numbers, then ${p_{(n+1)}^{1/(n+1)}< p_{n}^{1/n}}$ for every ${n\\geq 1}$. Rosser's inequality for the ${n}$th and ${(n+1)}$th roots, changes from strictly increasing to strictly decreasing for ${n\\geq 21}$. The inequality is con...

  11. Unpacking Intuition: A Conjecture

    OpenAIRE

    2009-01-01

    Can intuition be taught? The way in which faces are recognized, the structure of natural classes, and the architecture of intuition may all be instances of the same process. The conjecture that intuition is a species of recognition memory implies that human intuitive decision making can be enormously enhanced by virtual simulation.

  12. Serre’s conjecture

    CERN Document Server

    Lam, T Y

    1978-01-01

    From the Preface: "I felt it would be useful for graduate students to see a detailed account of the sequence of mathematical developments which was inspired by the Conjecture, and which ultimately led to its full solution.... I offered a course on Serre's Conjecture to a small group of graduate students in January, 1977 [at the University of California, Berkeley] one year after its solution by Quillen and Suslin. My course was taught very much in the spirit of a mathematical 'guided tour'. Volunteering as the guide, I took upon myself the task of charting a route through all the beautiful mathematics surrounding the main problem to be treated; the 'guide' then leads his audience through the route, on to the destination, pointing out the beautiful sceneries and historical landmarks along the way."

  13. On the Reinhardt Conjecture

    CERN Document Server

    Hales, Thomas C

    2011-01-01

    In 1934, Reinhardt asked for the centrally symmetric convex domain in the plane whose best lattice packing has the lowest density. He conjectured that the unique solution up to an affine transformation is the smoothed octagon (an octagon rounded at corners by arcs of hyperbolas). This article offers a detailed strategy of proof. In particular, we show that the problem is an instance of the classical problem of Bolza in the calculus of variations. A minimizing solution is known to exist. The boundary of every minimizer is a differentiable curve with Lipschitz continuous derivative. If a minimizer is piecewise analytic, then it is a smoothed polygon (a polygon rounded at corners by arcs of hyperbolas). To complete the proof of the Reinhardt conjecture, the assumption of piecewise analyticity must be removed, and the conclusion of smoothed polygon must be strengthened to smoothed octagon.

  14. The Parisi ultrametricity conjecture

    CERN Document Server

    Panchenko, Dmitry

    2011-01-01

    In this paper we prove that the support of a random measure on the unit ball of a separable Hilbert space that satisfies the Ghirlanda-Guerra identities must be ultrametric with probability one. This implies the Parisi ultrametricity conjecture in mean-field spin glass models, such as the Sherrington-Kirkpatrick and mixed $p$-spin models, for which Gibbs' measures are known to satisfy the Ghirlanda-Guerra identities in the thermodynamic limit.

  15. A Quantum Focussing Conjecture

    CERN Document Server

    Bousso, Raphael; Leichenauer, Stefan; Wall, and Aron C

    2015-01-01

    We propose a universal inequality that unifies the Bousso bound with the classical focussing theorem. Given a surface $\\sigma$ that need not lie on a horizon, we define a finite generalized entropy $S_\\text{gen}$ as the area of $\\sigma$ in Planck units, plus the von Neumann entropy of its exterior. Given a null congruence $N$ orthogonal to $\\sigma$, the rate of change of $S_\\text{gen}$ per unit area defines a quantum expansion. We conjecture that the quantum expansion cannot increase along $N$. This extends the notion of universal focussing to cases where quantum matter may violate the null energy condition. Integrating the conjecture yields a precise version of the Strominger-Thompson Quantum Bousso Bound. Applied to locally parallel light-rays, the conjecture implies a Quantum Null Energy Condition: a lower bound on the stress tensor in terms of the second derivative of the von Neumann entropy. We sketch a proof of this novel relation in quantum field theory.

  16. Green's conjecture for general covers

    CERN Document Server

    Aprodu, Marian

    2011-01-01

    We establish Green's syzygy conjecture for classes of covers of curves of higher Clifford dimension. These curves have an infinite number of minimal pencils, in particular they do not verify a well-known Brill-Noether theoretic sufficient condition that implies Green's conjecture. Secondly, we study syzygies of curves with a fixed point free involution and prove that sections of Nikulin surfaces of minimal Picard number 9, verify the classical Green Conjecture but fail the Prym-Green Conjecture on syzygies of Prym-canonical curves. This provides an explicit locus in the moduli space R_g where Green's Conjecture is known to hold.

  17. Generalizing Giuga's conjecture

    CERN Document Server

    Grau, José María

    2011-01-01

    In 1950 G. Giuga studied the congruence $\\sum_{j=1}^{n-1} j^{n-1} \\equiv -1$ (mod $n$) and conjectured that it was only satisfied by prime numbers. In this work we generalize Giuga's ideas considering, for each $k \\in \\mathbb{N}$, the congruence $\\sum_{j=1}^{n-1} j^{k(n-1)} \\equiv -1$ (mod $n$). It particular, it is proved that a pair $(n,k)\\in \\mathbb{N}^2$ (with composite $n$) satisfies the congruence if and only if $n$ is a Giuga Number and $ \\lambda(n)/\\gcd(\\lambda(n),n-1)$ divides $k$. In passing, we establish some new characterizations of Giuga Numbers.

  18. Philosophical conjectures and their refutation.

    Science.gov (United States)

    Kluge, A G

    2001-06-01

    Sir Karl Popper is well known for explicating science in falsificationist terms, for which his degree of corroboration formalism, C(h,e,b), has become little more than a symbol. For example, de Queiroz and Poe in this issue argue that C(h,e,b) reduces to a single relative (conditional) probability, p(e,hb), the likelihood of evidence e, given both hypothesis h and background knowledge b, and in reaching that conclusion, without stating or expressing it, they render Popper a verificationist. The contradiction they impose is easily explained--de Queiroz and Poe fail to take account of the fact that Popper derived C(h,e,b) from absolute (logical) probability and severity of test, S(e,h,b), where critical evidence, p(e,b), is fundamental. Thus, de Queiroz and Poe's conjecture that p(e,hb) = C(h,e,b) is refuted. Falsificationism, not verificationism, remains a fair description of the parsimony method of inference used in phylogenetic systematics, not withstanding de Queiroz and Poe's mistaken understanding that "statistical" probability justifies that method. Although de Queiroz and Poe assert that maximum likelihood has the power "to explain data", they do not successfully demonstrate how causal explanation is achieved or what it is that is being explained. This is not surprising, bearing in mind that what is assumed about character evolution in the accompanying likelihood model M cannot then be explained by the results of a maximum likelihood analysis.

  19. On Murty-Simon Conjecture

    CERN Document Server

    Wang, Tao

    2012-01-01

    A graph is diameter two edge-critical if its diameter is two and the deletion of any edge increases the diameter. Murty and Simon conjectured that the number of edges in a diameter two edge-critical graph on $n$ vertices is at most $\\lfloor \\frac{n^{2}}{4} \\rfloor$ and the extremal graph is the complete bipartite graph $K_{\\lfloor \\frac{n}{2} \\rfloor, \\lceil \\frac{n}{2} \\rceil}$. In the series papers [8-10], the Murty-Simon Conjecture stated by Haynes et al is not the original conjecture, indeed, it is only for the diameter two edge-critical graphs of even order. Haynes et al proved the conjecture for the graphs whose complements have diameter three but only with even vertices. In this paper, we prove the Murty-Simon Conjecture for the graphs whose complements have diameter three, not only with even vertices but also odd ones.

  20. On Lange's Conjecture

    CERN Document Server

    Teixidor-i-Bigas, M

    1997-01-01

    Let C be an algebraic curve of genus g. Let E be a vector bundle of rank n and degree d. Consider among all subbundles F' of E of rank n' those of maximal degree d'. Then s_n'(E)= n'd-nd'\\le n'(n-n')g. If E is stable s_n'(E)>0 while if E is generic s_n'(E)\\ge n'(n-n')(g-1) . The following statement was conjectured by Lange: If 0

  1. The Lemur Conjecture

    Science.gov (United States)

    Lanzagorta, Marco; Jitrik, Oliverio; Uhlmann, Jeffrey; Venegas-Andraca, Salvador E.

    2017-05-01

    In previous research we designed an interferometric quantum seismograph that uses entangled photon states to enhance sensitivity in an optomechanic device. However, a spatially-distributed array of such sensors, with each sensor measuring only nm-vibrations, may not provide sufficient sensitivity for the prediction of major earthquakes because it fails to exploit potentially critical phase information. We conjecture that relative phase information can explain the anecdotal observations that animals such as lemurs exhibit sensitivity to impending earthquakes earlier than can be done confidently with traditional seismic technology. More specifically, we propose that lemurs use their limbs as ground motion sensors and that relative phase differences are fused in the brain in a manner similar to a phased-array or synthetic-aperture radar. In this paper we will describe a lemur-inspired quantum sensor network for early warning of earthquakes. The system uses 4 interferometric quantum seismographs (e.g., analogous to a lemurs limbs) and then conducts phase and data fusion of the seismic information. Although we discuss a quantum-based technology, the principles described can also be applied to classical sensor arrays

  2. Saari's Conjecture in Celestial Mechanics

    Science.gov (United States)

    Diacu, Florin; Fujiwara, Toshiaki; Pérez-Chavela, Ernesto; Santoprete, Manuele

    2008-09-01

    In 1969, D. Saari conjectured that the only solutions of the Newtonian n-body problem that have constant moment of inertia are relative equilibria. For n = 3, there is a computer assisted proof of this conjecture given by R. Moeckel in 2005, [10]. The collinear case was solved the same year by F. Diacu, E. Pérez-Chavela, and M. Santoprete, [4], All the other cases are open. Denoting by U the potential energy, Saari's homographic conjecture states that if along an orbit of the n-body problem IU2 is constant, then the orbit is a homographic solution, i.e. a solution whose initial configuration remains similar to itself. In this paper, we discuss both conjectures and survey the proof of the latter for a large set of initial data. This survey follows our previous paper on this subject, [5].

  3. A proof of Sethares' conjecture

    Institute of Scientific and Technical Information of China (English)

    YAO; Guowu

    2004-01-01

    Let ψ(z) be holomorphic in the unit disk △ and meromorphic on -△. Suppose f is a Teichmuller mapping with complex dilatation k-ψ/|ψ|. In 1968, Sethares conjectured that f is extremal if and only if either (i) ψ has a double pole or (ii) ψ has no pole of order exceeding two on △. The "if" part of the conjecture had been solved by himself. We will give the affirmative answer to the "only if" part of the conjecture. In addition, a more general criterion for extremality of quasiconformal mappings is constructed in this paper,which generalizes the "if" part of Sethares' conjecture and improves the result by Reich and Shapiro in 1990.

  4. On a conjecture of Pomerance

    CERN Document Server

    Hajdu, L; Tijdeman, R

    2011-01-01

    We say that k is a P-integer if the first phi(k) primes coprime to k form a reduced residue system modulo k. In 1980 Pomerance proved the finiteness of the set of P-integers and conjectured that 30 is the largest P-integer. We prove the conjecture assuming the Riemann Hypothesis. We further prove that there is no P-integer between 30 and 10^11 and none above 10^3500.

  5. "Conjectural" links in complex networks

    Science.gov (United States)

    Snarskii, A. A.; Zorinets, D. I.; Lande, D. V.

    2016-11-01

    This paper introduces the concept of Conjectural Link for Complex Networks, in particular, social networks. Conjectural Link we understand as an implicit link, not available in the network, but supposed to be present, based on the characteristics of its topology. It is possible, for example, when in the formal description of the network some connections are skipped due to errors, deliberately hidden or withdrawn (e.g. in the case of partial destruction of the network). Introduced a parameter that allows ranking the Conjectural Link. The more this parameter - the more likely that this connection should be present in the network. This paper presents a method of recovery of partially destroyed Complex Networks using Conjectural Links finding. Presented two methods of finding the node pairs that are not linked directly to one another, but have a great possibility of Conjectural Link communication among themselves: a method based on the determination of the resistance between two nodes, and method based on the computation of the lengths of routes between two nodes. Several examples of real networks are reviewed and performed a comparison to know network links prediction methods, not intended to find the missing links in already formed networks.

  6. Warping the Weak Gravity Conjecture

    Directory of Open Access Journals (Sweden)

    Karta Kooner

    2016-08-01

    Full Text Available The Weak Gravity Conjecture, if valid, rules out simple models of Natural Inflation by restricting their axion decay constant to be sub-Planckian. We revisit stringy attempts to realise Natural Inflation, with a single open string axionic inflaton from a probe D-brane in a warped throat. We show that warped geometries can allow the requisite super-Planckian axion decay constant to be achieved, within the supergravity approximation and consistently with the Weak Gravity Conjecture. Preliminary estimates of the brane backreaction suggest that the probe approximation may be under control. However, there is a tension between large axion decay constant and high string scale, where the requisite high string scale is difficult to achieve in all attempts to realise large field inflation using perturbative string theory. We comment on the Generalized Weak Gravity Conjecture in the light of our results.

  7. On the base sequence conjecture

    CERN Document Server

    Djokovic, Dragomir Z

    2010-01-01

    Let BS(m,n) denote the set of base sequences (A;B;C;D), with A and B of length m and C and D of length n. The base sequence conjecture (BSC) asserts that BS(n+1,n) exist (i.e., are non-empty) for all n. This is known to be true for n <= 36 and when n is a Golay number. We show that it is also true for n=37 and n=38. It is worth pointing out that BSC is stronger than the famous Hadamard matrix conjecture. In order to demonstrate the abundance of base sequences, we have previously attached to BS(n+1,n) a graph Gamma_n and computed the Gamma_n for n <= 27. We now extend these computations and determine the Gamma_n for n=28,...,35. We also propose a conjecture describing these graphs in general.

  8. Extensions of the Multiplicity Conjecture

    OpenAIRE

    2005-01-01

    The Multiplicity conjecture of Herzog, Huneke, and Srinivasan states an upper bound for the multiplicity of any graded $k$-algebra as well as a lower bound for Cohen-Macaulay algebras. In this note we extend this conjecture in several directions. We discuss when these bounds are sharp, find a sharp lower bound in case of not necessarily arithmetically Cohen-Macaulay one-dimensional schemes of 3-space, and we propose an upper bound for finitely generated graded torsion modules. We establish th...

  9. On a conjecture concerning helly circle graphs

    Directory of Open Access Journals (Sweden)

    Durán Guillermo

    2003-01-01

    Full Text Available We say that G is an e-circle graph if there is a bijection between its vertices and straight lines on the cartesian plane such that two vertices are adjacent in G if and only if the corresponding lines intersect inside the circle of radius one. This definition suggests a method for deciding whether a given graph G is an e-circle graph, by constructing a convenient system S of equations and inequations which represents the structure of G, in such a way that G is an e-circle graph if and only if S has a solution. In fact, e-circle graphs are exactly the circle graphs (intersection graphs of chords in a circle, and thus this method provides an analytic way for recognizing circle graphs. A graph G is a Helly circle graph if G is a circle graph and there exists a model of G by chords such that every three pairwise intersecting chords intersect at the same point. A conjecture by Durán (2000 states that G is a Helly circle graph if and only if G is a circle graph and contains no induced diamonds (a diamond is a graph formed by four vertices and five edges. Many unsuccessful efforts - mainly based on combinatorial and geometrical approaches - have been done in order to validate this conjecture. In this work, we utilize the ideas behind the definition of e-circle graphs and restate this conjecture in terms of an equivalence between two systems of equations and inequations, providing a new, analytic tool to deal with it.

  10. Reed's Conjecture on hole expansions

    CERN Document Server

    Fouquet, Jean-Luc

    2012-01-01

    In 1998, Reed conjectured that for any graph $G$, $\\chi(G) \\leq \\lceil \\frac{\\omega(G) + \\Delta(G)+1}{2}\\rceil$, where $\\chi(G)$, $\\omega(G)$, and $\\Delta(G)$ respectively denote the chromatic number, the clique number and the maximum degree of $G$. In this paper, we study this conjecture for some {\\em expansions} of graphs, that is graphs obtained with the well known operation {\\em composition} of graphs. We prove that Reed's Conjecture holds for expansions of bipartite graphs, for expansions of odd holes where the minimum chromatic number of the components is even, when some component of the expansion has chromatic number 1 or when a component induces a bipartite graph. Moreover, Reed's Conjecture holds if all components have the same chromatic number, if the components have chromatic number at most 4 and when the odd hole has length 5. Finally, when $G$ is an odd hole expansion, we prove $\\chi(G)\\leq\\lceil\\frac{\\omega(G)+\\Delta(G)+1}{2}\\rceil+1$.

  11. Conjectured enumeration of Vassiliev invariants

    CERN Document Server

    Broadhurst, D J

    1997-01-01

    These conjectures are motivated by successful enumerations of irreducible Euler sums. Predictions for $\\beta_{15,10}$, $\\beta_{16,12}$ and $\\beta_{19,16}$ suggest that the action of sl and osp Lie algebras, on baguette diagrams with ladder insertions, fails to detect an invariant in each case.

  12. Proof of the BMV Conjecture

    CERN Document Server

    Stahl, Herbert R

    2011-01-01

    We prove the BMV (Bessis, Moussa, Villani, 1975) conjecture, which states that the function t -> Tr exp(A-tB), t \\geq 0, is the Laplace transform of a positive measure on [0,\\infty) if A and B are n x n Hermitian matrices and B is positive semidefinite.

  13. On a conjecture of Widom

    Energy Technology Data Exchange (ETDEWEB)

    Borodin, Alexei [Department of Mathematics, California Institute of Technology, Mathematics 253-37, Caltech, Pasadena, CA 91125 (United States); Novikov, Alexei [Department of Mathematics, Penn State University, University Park, State College, PA 16802 (United States)

    2006-07-14

    We prove a conjecture of Widom (2002 Int. Math. Res. Not. 455-64 (Preprint math/0108008)) about the reality of eigenvalues of certain infinite matrices arising in asymptotic analysis of large Toeplitz determinants. As a byproduct, we obtain a new proof of Okounkov's formula for the (determinantal) correlation functions of the Schur measures on partitions.

  14. Conjecture of Alexander and Orbach.

    Science.gov (United States)

    Rudra, Jayanta; Doiron, Curtis

    2009-03-01

    The dynamical properties of fractal networks have received wide range of attention. Works on this area by several pioneering authors^1-2 have led to the introduction of the spectral dimension that dictates the dynamic properties on a fractal lattice. Most of the studies involving spectral dimension have been performed on a type of fractal lattice known as percolation network. Alexander and Orbach^2 conjectured that the spectral dimension might be exactly 4/3 for percolation networks with Euclidean dimension de >= 2. Recent numerical simulations, however, could not decisively prove or disprove this conjecture, although there are other indirect evidences that it is true. We apply a stochastic approach^3 to determine the spectral dimension of percolation network for de >= 2 and check the validity of the Alexander-Orbach conjecture. Our preliminary results on 2- and 3-dimensional percolation networks indeed show that Alexander-Orbach conjecture is true, resolving a long-standing debate. References: 1. P. G. deGennes, La Recherche 7 (1976) 919. 2. S. Alexander and R. Orbach, J. Phys. Lett. (Paris) 43 (1982) L625. 3. J. Rudra and J. Kozak, Phys. Lett A 151 (1990) 429.

  15. Multi - instantons and Maldacena's conjecture

    NARCIS (Netherlands)

    Dorey, N.; Hollowood, T.J.; Khoze, V.V.; Mattis, M.P.; Vandoren, S.

    2007-01-01

    We examine certain n-point functions Gn in N = 4 supersymmetric SU(N) gauge theory at the conformal point. In the large-N limit, we are able to sum all leading-order multiinstanton contributions exactly. We find compelling evidence for Maldacena’s conjecture: (1) The large-N k-instanton collective c

  16. On the Strong Direct Summand Conjecture

    Science.gov (United States)

    McCullough, Jason

    2009-01-01

    In this thesis, our aim is the study the Vanishing of Maps of Tor Conjecture of Hochster and Huneke. We mainly focus on an equivalent characterization called the Strong Direct Summand Conjecture, due to N. Ranganathan. Our results are separated into three chapters. In Chapter 3, we prove special cases of the Strong Direct Summand Conjecture in…

  17. Higher rank case of Dwork's conjecture

    CERN Document Server

    Wan, D

    2000-01-01

    This is the final version of ANT-0142 ("An embedding approach to Dwork's conjecture"). It reduces the higher rank case of the conjecture over a general base variety to the rank one case over the affine space. The general rank one case is completed in ANT-0235 "Rank one case of Dwork's conjecture". Both papers will appear in JAMS.

  18. Tsirelson's problem and Kirchberg's conjecture

    CERN Document Server

    Fritz, Tobias

    2010-01-01

    Tsirelson's problem asks whether the set of nonlocal quantum correlations with a tensor product structure for the Hilbert space of states coincides with the one where only commutativity between observables located at different sites is assumed. Here it is shown that Kirchberg's QWEP conjecture on C*-algebras implies a positive answer to this question for all bipartite scenarios. The main idea is very simple and consists of relabelling measurement outcomes by complex roots of unity, so that a k-ary observable becomes a unitary of order k. This relates Tsirelson's problem to tensor products of certain group C^*-algebras to which Kirchberg's conjecture applies. For related work, see the simultaneously appearing preprint by Junge et al.

  19. Stability, fragility, and Rota's Conjecture

    NARCIS (Netherlands)

    Mayhew, D.; Whittle, G.; Zwam, S.H.M. van

    2010-01-01

    Fix a matroid N. A matroid M is N-fragile if, for each element e of M, at least one of M\\e and M/e has no N-minor. The Bounded Canopy Conjecture is that all GF(q)-representable matroids M that have an N-minor and are N-fragile have branch width bounded by a constant depending only on q and N. A matr

  20. Stability, fragility, and Rota's Conjecture

    NARCIS (Netherlands)

    Mayhew, D.; Whittle, G.; Zwam, S.H.M. van

    2011-01-01

    Fix a matroid N. A matroid M is N-fragile if, for each element e of M, at least one of M\\e and M/e has no N-minor. The Bounded Canopy Conjecture is that all GF(q)-representable matroids M that have an N-minor and are N-fragile have branch width bounded by a constant depending only on q and N. A matr

  1. On a conjecture of Widom

    OpenAIRE

    Borodin, Alexei; Novikov, Alexei

    2014-01-01

    In 1969 Harold Widom published his seminal paper, which gave a complete description of orthogonal and Chebyshev polynomials on a system of smooth Jordan curves. When there were Jordan arcs present the theory of orthogonal polynomials turned out to be just the same, but for Chebyshev polynomials Widom's approach proved only an upper estimate, which he conjectured to be the correct asymptotic behavior. In this note we make some clarifications which will show that the situation is more complicated.

  2. 10 conjectures in additive number theory

    CERN Document Server

    Cloitre, Benoit

    2011-01-01

    Following an idea of Rowland we give a conjectural way to generate increasing sequences of primes using algorithms involving the gcd. These algorithms seem not so useless for searching primes since it appears we found sometime primes much more greater than the number of required iterations. In an other hand we propose new formulations of famous conjectures from the additive theory of numbers (the weak twin prime conjecture, the Polignac conjecture, the Goldbach conjecture or the very general Schinzel's hypothesis H). For the moment these are experimental results obtained using pari-gp.

  3. On two conjectures of Faith

    CERN Document Server

    Haim, M; Torrecillas, B

    2011-01-01

    We prove that a profinite algebra whose left (right) cyclic modules are torsionless is finite dimensional and QF. We give a relative version of the notion of left (right) PF ring for pseudocompact algebras and prove it is left-right symmetric and dual to the notion of quasi-co-Frobenius coalgebras. We also prove two ring theoretic conjectures of Faith, in the setting (and supplementary hypothesis) of profinite algebras: any profinite semiartinian selfinjective algebra is finite dimensional and QF, and any FGF profinite algebra is finite dimensional QF.

  4. A Generalization of Kneser's Conjecture

    CERN Document Server

    Hajiabolhassan, Hossein

    2009-01-01

    We investigate some coloring properties of Kneser graphs. A star-free coloring is a proper coloring $c:V(G)\\to \\Bbb{N}$ such that no path with three vertices may be colored with just two consecutive numbers. The minimum positive integer $t$ for which there exists a star-free coloring $c: V(G) \\to \\{1,2,..., t\\}$ is called the star-free chromatic number of $G$ and denoted by $\\chi_s(G)$. In view of Tucker-Ky Fan's lemma, we show that for any Kneser graph ${\\rm KG}(n,k)$ we have $\\chi_s({\\rm KG}(n,k))\\geq \\max\\{2\\chi({\\rm KG}(n,k))-10, \\chi({\\rm KG}(n,k))\\}$ where $n\\geq 2k \\geq 4$. Moreover, we show that $\\chi_s({\\rm KG}(n,k))=2\\chi({\\rm KG}(n,k))-2=2n-4k+2$ provided that $n \\leq {8\\over 3}k$. This gives a partial answer to a conjecture of [12]. Also, we conjecture that for any positive integers $n\\geq 2k \\geq 4$ we have $\\chi_s({\\rm KG}(n,k))= 2\\chi({\\rm KG}(n,k))-2$.

  5. A proof of the Goldbach conjecture

    CERN Document Server

    Tan, Shanguang

    2011-01-01

    The Goldbach conjecture was proved in this paper. The proof was by contradiction based on the fundamental theorem of arithmetic and the theory of Linear Algebra. First, by an assumption, the Goldbach conjecture was converted into a group of linear equations. Then, by investigating solutions to the group of linear equations, reductions to absurdity were derived to prove the assumption false. Hence, the Goldbach conjecture was proved that even numbers greater than 2 can be expressed as the sum of two primes.

  6. Hodge and Tate conjectures for hypergeometric sheaves

    CERN Document Server

    Terasoma, T

    1997-01-01

    A constructible sheaf corresponding to Gel'fand Zelevinski hypergeometric functions on a torus is called hypergeometric sheaf. We consider Hodge and Tate conjectrue for hypergeomtric sheaves. Hodge conjecture is formulated in terms of variation of Hodge strucure and Tate conjecture is done for l-adic sheaves on an open set of torus. We prove Hodge and Tate conjecture up to Hodge and Tate cycle of Fermat motifes. We use cohomological Mellin transform to get the main theorem.

  7. Gao's Conjecture on Zero-Sum Sequences

    Indian Academy of Sciences (India)

    B Sury; R Thangadurai

    2002-08-01

    In this paper, we shall address three closely-related conjectures due to van Emde Boas, W D Gao and Kemnitz on zero-sum problems on $\\mathbf{Z}_p \\oplus \\mathbf{Z}_p$. We prove a number of results including a proof of the conjecture of Gao for the prime = 7 (Theorem 3.1). The conjecture of Kemnitz is also proved (Propositions 4.6, 4.9, 4.10) for many classes of sequences.

  8. Rank one case of Dwork's conjecture

    CERN Document Server

    Wan, D

    2000-01-01

    This paper proves the general rank one case of Dwork's conjecture over the affine space. It generalizes and improves the method of ANT-0141 "Dwork's conjecture on unit root zeta functions" (Ann. Math., 150(1999), 867-929). In addition, explicit information about the zeros and poles (along the Gouv\\^ea-Mazur conjecture direction) for the unit root zeta function is obtained. The paper is to appear in JAMS.

  9. The Monodromy Conjecture for hyperplane arrangements

    CERN Document Server

    Budur, Nero; Teitler, Zach

    2009-01-01

    The Monodromy Conjecture asserts that if c is a pole of the local topological zeta function of a hypersurface, then exp(2\\pi c) is an eigenvalue of the monodromy on the cohomology of the Milnor fiber. A stronger version of the conjecture asserts that every pole is a root of the Bernstein-Sato polynomial of the hypersurface. In this note we prove the weak version of the conjecture for hyperplane arrangements. Furthermore, we reduce the strong version to the following conjecture: -n/d is always a root of the Bernstein-Sato polynomial of an indecomposable essential central hyperplane arrangement of d hyperplanes in the affine n-space.

  10. Closed-universe recollapse conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Barrow, J.D.; Galloway, G.J.; Tipler, F.J.

    1986-12-15

    It is widely believed that all expanding S/sup 3/ closed universes that satisfy the standard energy conditions recollapse to a second singularity. It is shown that this is false even for Friedmann universes: an ever-expanding S/sup 3/ Friedmann universe is constructed in which the matter tensor satisfies the strong, weak and dominant energy conditions and the generic condition. A general recollapse theorem for Friedmann universes is proved if the positive pressure criterion, dominant enery condition and matter regularity condition hold, then an S/sup 3/ Friedmann universe must recollapse. It is shown that all known vacuum solutions with Cauchy surface topology S/sup 3/ or S/sup 2/XS/sup 1/ recollapse, and we conjecture that this is a property of all vacuum solutions of Einstein's equations with such Cauchy surfaces.

  11. A Proof of Onsager's Conjecture

    CERN Document Server

    Isett, Philip

    2016-01-01

    For any $\\alpha 1/3$ due to [Eyink] and [Constantin, E, Titi], solves Onsager's conjecture that the exponent $\\alpha = 1/3$ marks the threshold for conservation of energy for weak solutions in the class $L_t^\\infty C_x^\\alpha$. The previous best results were solutions in the class $C_tC_x^\\alpha$ for $\\alpha < 1/5$, due to the author, and in the class $L_t^1 C_x^\\alpha$ for $\\alpha < 1/3$ due to Buckmaster, De Lellis and Sz\\'{e}kelyhidi, both based on the method of convex integration developed for the incompressible Euler equations by De Lellis and Sz\\'ekelyhidi. The present proof combines the method of convex integration and a new "gluing approximation" technique. The convex integration part of the proof relies on the "Mikado flows" introduced by [Daneri, Sz\\'ekelyhidi] and the framework of estimates developed in the author's previous work.

  12. Conformal Patterson-Walker metrics

    CERN Document Server

    Hammerl, Matthias; Šilhan, Josef; Taghavi-Chabert, Arman; Žádník, Vojtěch

    2016-01-01

    The classical Patterson-Walker construction of a split-signature (pseudo-)Riemannian structure from a given torsion-free affine connection is generalized to a construction of a split-signature conformal structure from a given projective class of connections. A characterization of the induced structures is obtained. We achieve a complete description of Einstein metrics in the conformal class formed by the Patterson-Walker metric. Finally, we describe all symmetries of the conformal Patterson-Walker metric. In both cases we obtain descriptions in terms of geometric data on the original structure.

  13. Yang-Mills Theory and the ABC Conjecture

    CERN Document Server

    He, Yang-Hui; Probst, Malte; Read, James

    2016-01-01

    We establish a precise correspondence between the ABC Conjecture and N=4 super-Yang-Mills theory. This is achieved by combining three ingredients: (i) Elkies' method of mapping ABC-triples to elliptic curves in his demonstration that ABC implies Mordell/Faltings; (ii) an explicit pair of elliptic curve and associated Belyi map given by Khadjavi-Scharaschkin; and (iii) the fact that the bipartite brane-tiling/dimer model for a gauge theory with toric moduli space is a particular dessin d'enfant in the sense of Grothendieck. We explore this correspondence for the highest quality ABC-triples as well as large samples of random triples. The Conjecture itself is mapped to a statement about the fundamental domain of the toroidal compactification of the string realization of N=4 SYM.

  14. The André-Oort conjecture

    NARCIS (Netherlands)

    Edixhoven, B.; Taelman, L.

    2015-01-01

    The André-Oort conjecture is a problem in algebraic geometry from around 1990, with arithmetic, analytic and differential geometric aspects. Klingler, Ullmo and Yafaev, as well as Pila and Tsimerman have now shown that the Generalized Riemann Hypothesis implies the Andr´e-Oort conjecture. Both proof

  15. Green's Conjecture for the generic canonical curve

    OpenAIRE

    Teixidor-I-Bigas, Montserrat

    1998-01-01

    Green's Conjecture states the following : syzygies of the canonical model of a curve are simple up to the p^th stage if and only if the Clifford index of C is greater than p. We prove that the generic curve of genus g satisfies Green's conjecture.

  16. The André-Oort conjecture

    NARCIS (Netherlands)

    Edixhoven, B.; Taelman, L.

    2015-01-01

    The André-Oort conjecture is a problem in algebraic geometry from around 1990, with arithmetic, analytic and differential geometric aspects. Klingler, Ullmo and Yafaev, as well as Pila and Tsimerman have now shown that the Generalized Riemann Hypothesis implies the Andr´e-Oort conjecture. Both proof

  17. On So's conjecture for integral circulant graphs

    Directory of Open Access Journals (Sweden)

    J.W. Sander

    2015-04-01

    According to a conjecture of {\\sc So} two integral circulant graphs are isomorphic if and only if they are isospectral, i.e. they have the same eigenvalues (counted with multiplicities. We prove a weaker form of this conjecture, namely, that two integral circulant graphs with multiplicative divisor sets are isomorphic if and only if their spectral vectors coincide.

  18. Mathematics Reading——Goldbach's Conjecture

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    A mathematician who thinks some statement seems true but can't prove it's true may then advance it as a conjecture. The most famous actual conjecture is one made by a German mathematician who works in Russia,Christian Goldbach (1690 1764).

  19. Fall prevention walker during rehabilitation

    Science.gov (United States)

    Tee, Kian Sek; E, Chun Zhi; Saim, Hashim; Zakaria, Wan Nurshazwani Wan; Khialdin, Safinaz Binti Mohd; Isa, Hazlita; Awad, M. I.; Soon, Chin Fhong

    2017-09-01

    This paper proposes on the design of a walker for the prevention of falling among elderlies or patients during rehabilitation whenever they use a walker to assist them. Fall happens due to impaired balance or gait problem. The assistive device is designed by applying stability concept and an accelerometric fall detection system is included. The accelerometric fall detection system acts as an alerting device that acquires body accelerometric data and detect fall. Recorded accelerometric data could be useful for further assessment. Structural strength of the walker was verified via iterations of simulation using finite element analysis, before being fabricated. Experiments were conducted to identify the fall patterns using accelerometric data. The design process and detection of fall pattern demonstrates the design of a walker that could support the user without fail and alerts the helper, thus salvaging the users from injuries due to fall and unattended situation.

  20. On topological relaxations of chromatic conjectures

    CERN Document Server

    Simonyi, Gábor

    2010-01-01

    There are several famous unsolved conjectures about the chromatic number that were relaxed and already proven to hold for the fractional chromatic number. We discuss similar relaxations for the topological lower bound(s) of the chromatic number. In particular, we prove that such a relaxed version is true for the Behzad-Vizing conjecture and also discuss the conjectures of Hedetniemi and of Hadwiger from this point of view. For the latter, a similar statement was already proven in an earlier paper of the first author with G. Tardos, our main concern here is that the so-called odd Hadwiger conjecture looks much more difficult in this respect. We prove that the statement of the odd Hadwiger conjecture holds for large enough Kneser graphs and Schrijver graphs of any fixed chromatic number.

  1. Volume conjecture for $SU(n)$-invariants

    CERN Document Server

    Chen, Qingtao; Zhu, Shengmao

    2015-01-01

    This paper discuss an intrinsic relation among congruent relations \\cite{CLPZ}, cyclotomic expansion and Volume Conjecture for $SU(n)$ invariants. Motivated by the congruent relations for $SU(n)$ invariants obtained in our previous work \\cite{CLPZ}, we study certain limits of the $SU(n)$ invariants at various roots of unit. First, we prove a new symmetry property for the $SU(n)$ invariants by using a symmetry of colored HOMFLYPT invariants. Then we propose some conjectural formulas including the cyclotomic expansion conjecture and volume conjecture for $SU(n)$ invariants (specialization of colored HOMFLYPT invariants). We also give the proofs of these conjectural formulas for the case of figure-eight knot.

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  3. Axion monodromy and the weak gravity conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Hebecker, Arthur; Rompineve, Fabrizio [Heidelberg Univ. (Germany). Inst. for Theoretical Physics; Westphal, Alexander [DESY Hamburg (Germany). Theory Group

    2015-12-15

    Axions with broken discrete shift symmetry (axion monodromy) have recently played a central role both in the discussion of inflation and the 'relaxion' approach to the hierarchy problem. We suggest a very minimalist way to constrain such models by the weak gravity conjecture for domain walls: While the electric side of the conjecture is always satisfied if the cosine-oscillations of the axion potential are sufficiently small, the magnetic side imposes a cutoff, Λ{sup 3}∝mfM{sub pl}, independent of the height of these 'wiggles'. We compare our approach with the recent related proposal by Ibanez, Montero, Uranga and Valenzuela. We also discuss the non-trivial question which version, if any, of the weak gravity conjecture for domain walls should hold. In particular, we show that string compactifications with branes of different dimensions wrapped on different cycles lead to a 'geometric weak gravity conjecture' relating volumes of cycles, norms of corresponding forms and the volume of the compact space. Imposing this 'geometric conjecture', e.g. on the basis of the more widely accepted weak gravity conjecture for particles, provides at least some support for the (electric and magnetic) conjecture for domain walls.

  4. The Gross conjecture over rational function fields

    Institute of Scientific and Technical Information of China (English)

    OUYANG; Yi

    2005-01-01

    We study the Gross conjecture for the cyclotomic function field extension k(∧f)/k where k = Fq(t) is the rational function field and f is a monic polynomial in Fq[t].We prove the conjecture in the Fermat curve case(i.e., when f = t(t - 1)) by a direct calculation. We also prove the case when f is irreducible, which is analogous to the Weil reciprocity law. In the general case, we manage to show the weak version of the Gross conjecture here.

  5. Numerical Evidence for a Conjecture of Poonen

    CERN Document Server

    Hutz, Benjamin

    2009-01-01

    The purpose of this note is give some evidence in support of conjectures of Poonen, and Morton and Silverman, on the periods of rational numbers under the iteration of quadratic polynomials. In particular, Poonen conjectured that there are at most 9 periodic points defined over the rational numbers for any map in the family x^2 + c for c rational. We verify this conjecture for c values up to height 10^8. For quadratic number fields, we provide evidence that the upper bound on the exact period of Q-rational periodic point is 6.

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  12. Drug Facts

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  13. An approximate version of Sidorenko's conjecture

    CERN Document Server

    Conlon, David; Sudakov, Benny

    2010-01-01

    A beautiful conjecture of Erd\\H{o}s-Simonovits and Sidorenko states that if H is a bipartite graph, then the random graph with edge density p has in expectation asymptotically the minimum number of copies of H over all graphs of the same order and edge density. This conjecture also has an equivalent analytic form and has connections to a broad range of topics, such as matrix theory, Markov chains, graph limits, and quasirandomness. Here we prove the conjecture if H has a vertex complete to the other part, and deduce an approximate version of the conjecture for all H. Furthermore, for a large class of bipartite graphs, we prove a stronger stability result which answers a question of Chung, Graham, and Wilson on quasirandomness for these graphs.

  14. Trivalent graphs, volume conjectures and character varieties

    CERN Document Server

    Nawata, Satoshi; Zodinmawia,

    2014-01-01

    The generalized volume conjecture and the AJ conjecture (a.k.a. the quantum volume conjecture) are extended to $U_q(sl_2)$ colored quantum invariants of trivalent graphs. The SL(2,C) character variety of the fundamental group of the complement of a trivalent graph with $E$ edges in $S^3$ is a Lagrangian subvariety of the Hitchin moduli space over the Riemann surface of genus $g=E/3+1$. The configuration of the character variety is locally determined by large color asymptotics of the quantum invariants of the trivalent graph in terms of complex Fenchel-Nielsen coordinates. Moreover, the q-holonomic difference equation of the quantum invariants provides the quantization of the character variety. In particular, we investigate both the conjectures for the theta and tetrahedron graphs.

  15. Proof of the Witten-Yau Conjecture

    CERN Document Server

    Reid, James A

    2012-01-01

    The Witten-Yau theorem in the AdS/CFT correspondence conjectures that the conformal boundary to AdS space must possess a metric of non-negative scalar curvature for the conformal field theory defined thereon to be free of pathologies. By employing various tools from conformal geometry - such as almost Einstein structures, collapsing sphere products and tractor bundles - we rigorously prove this conjecture.

  16. On a conjecture on linear systems

    Indian Academy of Sciences (India)

    SONICA ANAND

    2017-06-01

    In a remark to Green’s conjecture, Paranjape and Ramanan analysed the vector bundle $E$ which is the pullback by the canonical map of the universal quotient bundle $T_\\mathbb{P}^{g−1}(−1)$ on $\\mathbb{P}^{g−1}$ and stated a more general conjecture and proved it for the curveswith Clifford Index 1 (trigonal and plane quintics). In this paper, we state the conjecturefor general linear systems and obtain results for the case of hyper-elliptic curves.

  17. SYM Correlators and the Maldacena Conjecture

    OpenAIRE

    Trittmann, Uwe

    2002-01-01

    We report on progress in evaluating quantum filed theories with supersymmetric discrete light-cone quantization (SDLCQ). We compare the method to lattice gauge theory and point out its relevance for lattice calculations. As an exciting application we present a test of the Maldacena conjecture. We test the conjecture by evaluating the correlator of the stress-energy tensor in the strong coupling field theory and comparing to the string theory prediction of its behavior as a function of the dis...

  18. Intelligently Controllable Walker with Magnetorheological Fluid Brake

    Science.gov (United States)

    Kikuchi, Takehito; Tanida, Sosuke; Tanaka, Toshimasa; Kobayashi, Keigo; Mitobe, Kazuhisa

    Caster walkers are supporting frames with casters and wheels. These tools are regularly utilized as life support tools or walking rehabilitation tools in hospitals, nursing homes and individual residences. Users of the walkers can easily move it thanks to its wheels and casters. However falling accidents often happen when it moves without users. The falling accident is very serious problem and one of leading causes of secondary injuries. In the other case, it is hard to move to desired directions if users have imbalance in their motor functions or sensory functions, e.g., hemiplegic patients. To improve safeness and operability of the walkers, we installed compact MR fluid brakes on the wheels and controlled walking speed and direction of the walker. We named this intelligently controllable walker, “i-Walker” and discussed on the control methods and experimental results in this paper. Preliminary trials for direction control of the first-generation of the i-Walker (i-Walker1) are presented. On the basis of the results, we improved the control method and hardware of the i-Walker1, and developed the second-generation (i-Walker2). System description and experimental results of the i-Walker2 are also described. The i-Walker2 has better operability and lower energy consumption than that of the i-Walker1. The line-tracing controller of the i-Walker2 well controls human motions during walking experiments on the target straight line.

  19. Madame Kara Walker, notre artiste

    Directory of Open Access Journals (Sweden)

    Riché Deianne Richardson

    2008-01-01

    Full Text Available « Mon Ennemi, Mon Frère, Mon Bourreau, Mon Amour, » the epic exhibition at ARC/ Musée d’art moderne de la ville de Paris running from 20 June to 9 September, reveals the creative genius and vision of the artist Kara Walker, who was born in Stockton, California in 1969. The show is her most comprehensive one yet in Europe and includes the form that Walker has uniquely developed and for which she is best known, cut-out black silhouettes that are sometimes small and at other times gigantic and r...

  20. On William Walker and his Connections with and Some Secret Societies

    OpenAIRE

    Abarca Hernández, Oriester; Arias Alpízar, Luz Mary

    2016-01-01

    According to various sources, William Walker received the aid of secret societies for his filibustering raids in Central America. Four main sources were selected to examine some aspects of the problem that arises in this article: Did Walker’s projects have a real connection with secret organizations? The emphasis is on criticism of sources and any interest that lies behind the facts stated. Según diversas fuentes, William Walker recibió la ayuda de sociedades secretas para sus incursiones ...

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  3. The 1 , 2 , 3-Conjecture And 1 , 2-Conjecture For Sparse Graphs

    Directory of Open Access Journals (Sweden)

    Cranston Daniel W.

    2014-11-01

    Full Text Available The 1, 2, 3-Conjecture states that the edges of a graph without isolated edges can be labeled from {1, 2, 3} so that the sums of labels at adjacent vertices are distinct. The 1, 2-Conjecture states that if vertices also receive labels and the vertex label is added to the sum of its incident edge labels, then adjacent vertices can be distinguished using only {1, 2}. We show that various configurations cannot occur in minimal counterexamples to these conjectures. Discharging then confirms the conjectures for graphs with maximum average degree less than 8/3. The conjectures are already confirmed for larger families, but the structure theorems and reducibility results are of independent interest.

  4. Eigenvalue conjecture and colored Alexander polynomials

    CERN Document Server

    Mironov, A

    2016-01-01

    We connect two important conjectures in the theory of knot polynomials. The first one is the property Al_R(q) = Al_{[1]}(q^{|R|}) for all single hook Young diagrams R, which is known to hold for all knots. The second conjecture claims that all the mixing matrices U_{i} in the relation {\\cal R}_i = U_i{\\cal R}_1U_i^{-1} between the i-th and the first generators {\\cal R}_i of the braid group are universally expressible through the eigenvalues of {\\cal R}_1. Since the above property of Alexander polynomials is very well tested, this relation provides a new support to the eigenvalue conjecture, especially for i>2, when its direct check by evaluation of the Racah matrices and their convolutions is technically difficult.

  5. Evidence for a Lattice Weak Gravity Conjecture

    CERN Document Server

    Heidenreich, Ben; Rudelius, Tom

    2016-01-01

    The Weak Gravity Conjecture postulates the existence of superextremal charged particles, i.e. those with mass smaller than or equal to their charge in Planck units. We present further evidence for our recent observation that in known examples a much stronger statement is true: an infinite tower of superextremal particles of different charges exists. We show that effective Kaluza-Klein field theories and perturbative string vacua respect the Sublattice Weak Gravity Conjecture, namely that a finite index sublattice of the full charge lattice exists with a superextremal particle at each site. In perturbative string theory we show that this follows from modular invariance. However, we present counterexamples to the stronger possibility that a superextremal state exists at every lattice site, including an example in which the lightest charged state is subextremal. The Sublattice Weak Gravity Conjecture has many implications both for abstract theories of quantum gravity and for real-world physics. For instance, it ...

  6. The dynamical Mordell-Lang conjecture

    CERN Document Server

    Bell, Jason P; Tucker, Thomas J

    2016-01-01

    The Dynamical Mordell-Lang Conjecture is an analogue of the classical Mordell-Lang conjecture in the context of arithmetic dynamics. It predicts the behavior of the orbit of a point x under the action of an endomorphism f of a quasiprojective complex variety X. More precisely, it claims that for any point x in X and any subvariety V of X, the set of indices n such that the n-th iterate of x under f lies in V is a finite union of arithmetic progressions. In this book the authors present all known results about the Dynamical Mordell-Lang Conjecture, focusing mainly on a p-adic approach which provides a parametrization of the orbit of a point under an endomorphism of a variety.

  7. Note on the reduction of Alperin's Conjecture

    CERN Document Server

    Puig, Lluis

    2011-01-01

    In a recent paper, Gabriel Navarro and Pham Huu Tiep show that the so-called Alperin Weight Conjecture can be verified via the Classification of the Finite Simple Groups, provided any simple group fulfills a very precise list of conditions. Our purpose here is to show to the interested reader that the results in our book "Frobenius categories versus Brauer blocks", Progress in Math. 274(2009), and the reduction arguments in "On the reduction of Alperin's Conjecture to the quasi-simple groups", J. of Algebra 328(2011), suggest a numerical statement - implying Alperin's Conjecture block by block - which can be reduced again to check that the same holds on the quasi-simple groups and, this time, this statement on the quasi-simple groups follows from the list of conditions demanded by Navarro and Tiep.

  8. The volume conjecture and topological strings

    Science.gov (United States)

    Dijkgraaf, R.; Fuji, H.

    2009-09-01

    In this paper, we discuss a relation between Jones-Witten theory of knot invariants and topological open string theory on the basis of the volume conjecture. We find a similar Hamiltonian structure for both theories, and interpret the AJ conjecture as the D-module structure for a D-brane partition function. In order to verify our claim, we compute the free energy for the annulus contributions in the topological string using the Chern-Simons matrix model, and find that it coincides with the Reidemeister torsion in the case of the figure-eight knot complement and the SnapPea census manifold m009.

  9. The Volume Conjecture and Topological Strings

    CERN Document Server

    Dijkgraaf, Robbert

    2009-01-01

    In this paper, we discuss a relation between Jones-Witten theory of knot invariants and topological open string theory on the basis of the volume conjecture. We find a similar Hamiltonian structure for both theories, and interpret the AJ conjecture as the D-module structure for a D-brane partition function. In order to verify our claim, we compute the free energy for the annulus contributions in the topological string using the Chern-Simons matrix model, and find that it coincides with the Reidemeister torsion in the case of the figure-eight knot complement and the SnapPea census manifold m009.

  10. Thermodynamics of gravity favours Weak Censorship Conjecture

    CERN Document Server

    Acquaviva, Giovanni; Hamid, Aymen I M; Maharaj, Sunil D

    2015-01-01

    We use the formulation of thermodynamics of gravity as proposed by Clifton, Ellis and Tavakol on the gravitational collapse of dustlike matter, that violates the strong or weak cosmic censorship conjecture depending on the initial data. We transparently demonstrate that the gravitational entropy prefers the scenario where the stronger version is violated but the weak censorship conjecture is satisfied. This is a novel result, showing the weak cosmic censorship and hence the future asymptotically simple structure of spacetime, is being validated by the nature of gravity, without imposing any extra constraint on the form of matter.

  11. The real Fatou conjecture (AM-144)

    CERN Document Server

    Graczyk, Jacek

    2014-01-01

    In 1920, Pierre Fatou expressed the conjecture that--except for special cases--all critical points of a rational map of the Riemann sphere tend to periodic orbits under iteration. This conjecture remains the main open problem in the dynamics of iterated maps. For the logistic family x- ax(1-x), it can be interpreted to mean that for a dense set of parameters ""a,"" an attracting periodic orbit exists. The same question appears naturally in science, where the logistic family is used to construct models in physics, ecology, and economics. In this book, Jacek Graczyk and Grzegorz Swiatek provi

  12. Celebrating Cercignani's conjecture for the Boltzmann equation

    CERN Document Server

    Desvillettes, Laurent; Villani, Cédric

    2010-01-01

    Cercignani's conjecture assumes a linear inequality between the entropy and entropy production functionals for Boltzmann's nonlinear integral operator in rarefied gas dynamics. Related to the field of logarithmic Sobolev inequalities and spectral gap inequalities, this issue has been at the core of the renewal of the mathematical theory of convergence to thermodynamical equilibrium for rarefied gases over the past decade. In this review paper, we survey the various positive and negative results which were obtained since the conjecture was proposed in the 1980s.

  13. On a conjecture of Kaneko and Ohno

    CERN Document Server

    Li, Zhong-hua

    2011-01-01

    Let $X_0^{\\star}(k,n,s)$ denote the sum of all multiple zeta-star values of weight $k$, depth $n$ and height $s$. Kaneko and Ohno conjecture that for any positive integers $m,n,s$ with $m,n\\geqslant s$, the difference $(-1)^mX_0^{\\star}(m+n+1,n+1,s)-(-1)^nX_0^{\\star}(m+n+1,m+1,s)$ can be expressed as a polynomial of zeta values with rational coefficients. We give a proof of this conjecture in this paper.

  14. Celebrating Cercignani's conjecture for the Boltzmann equation

    KAUST Repository

    Villani, Cédric

    2011-01-01

    Cercignani\\'s conjecture assumes a linear inequality between the entropy and entropy production functionals for Boltzmann\\'s nonlinear integral operator in rarefied gas dynamics. Related to the field of logarithmic Sobolev inequalities and spectral gap inequalities, this issue has been at the core of the renewal of the mathematical theory of convergence to thermodynamical equilibrium for rarefied gases over the past decade. In this review paper, we survey the various positive and negative results which were obtained since the conjecture was proposed in the 1980s. © American Institute of Mathematical Sciences.

  15. Thermalization of Fermionic Quantum Walkers

    Science.gov (United States)

    Hamza, Eman; Joye, Alain

    2017-03-01

    We consider the discrete time dynamics of an ensemble of fermionic quantum walkers moving on a finite discrete sample, interacting with a reservoir of infinitely many quantum particles on the one dimensional lattice. The reservoir is given by a fermionic quasifree state, with free discrete dynamics given by the shift, whereas the free dynamics of the non-interacting quantum walkers in the sample is defined by means of a unitary matrix. The reservoir and the sample exchange particles at specific sites by a unitary coupling and we study the discrete dynamics of the coupled system defined by the iteration of the free discrete dynamics acting on the unitary coupling, in a variety of situations. In particular, in absence of correlation within the particles of the reservoir and under natural assumptions on the sample's dynamics, we prove that the one- and two-body reduced density matrices of the sample admit large times limits characterized by the state of the reservoir which are independent of the free dynamics of the quantum walkers and of the coupling strength. Moreover, the corresponding asymptotic density profile in the sample is flat and the correlations of number operators have no structure, a manifestation of thermalization.

  16. New experimental results concerning the Goldbach conjecture

    NARCIS (Netherlands)

    Deshouillers, J.-M.; Riele, H.J.J. te; Saouter, Y.

    1998-01-01

    The Goldbach conjecture states that every even integer $ge4$ can be written as a sum of two prime numbers. It is known to be true up to $4times 10^{11$. In this paper, new experiments on a Cray C916 supercomputer and on an SGI compute server with 18 R8000 CPUs are described, which extend this bound

  17. Geometric approach to Ending Lamination Conjecture

    OpenAIRE

    Soma, Teruhiko

    2008-01-01

    We present a new proof of the bi-Lipschitz model theorem, which occupies the main part of the Ending Lamination Conjecture proved by Minsky and Brock-Canary-Minsky. Our proof is done by using techniques of standard hyperbolic geometry as much as possible.

  18. Proof of the Thin Sandwich Conjecture

    CERN Document Server

    Bartnik, R; Bartnik, Robert; Fodor, Gyula

    1993-01-01

    We prove that the Thin Sandwich Conjecture in general relativity is valid, provided that the data $(g_{ab},\\dot g_{ab})$ satisfy certain geometric conditions. These conditions define an open set in the class of possible data, but are not generically satisfied. The implications for the ``superspace'' picture of the Einstein evolution equations are discussed.

  19. On the Ramanujan conjecture over number fields

    CERN Document Server

    Blomer, Valentin

    2010-01-01

    We extend to an arbitrary number field the best known bounds towards the Ramanujan conjecture for the groups GL(n), n=2, 3, 4. In particular, we present a technique allowing to overcome the analytic obstacles posed by the presence of an infinite group of units.

  20. The center conjecture for thick spherical buildings

    CERN Document Server

    Ramos-Cuevas, Carlos

    2009-01-01

    We prove that a convex subcomplex of a spherical building of type E7 or E8 is a subbuilding or the group of building automorphisms preserving the subcomplex has a fixed point in it. Together with previous results of Muehlherr-Tits, and Leeb and the author, this completes the proof of Tits' Center Conjecture for thick spherical buildings.

  1. Hod mice and the mouse set conjecture

    CERN Document Server

    Sargsyan, Grigor

    2015-01-01

    The author develops the theory of Hod mice below AD_{\\mathbb{R}}+ "\\Theta is regular". He uses this theory to show that HOD of the minimal model of AD_{\\mathbb{R}}+ "\\Theta is regular" satisfies GCH. Moreover, he shows that the Mouse Set Conjecture is true in the minimal model of AD_{\\mathbb{R}}+ "\\Theta is regular".

  2. An Intrinsic Approach to Lichnerowicz Conjecture

    Indian Academy of Sciences (India)

    Akhil Ranjan

    2000-02-01

    In this paper we give a proof of Lichnerowicz conjecture for compact simply connected manifolds which is intrinsic in the sense that it avoids the nice embeddings into eigenspaces of the Laplacian. Even if one wants to use these embeddings, this paper gives a more streamlined proof. As a byproduct, we get a simple criterion for a polynomial to be a Jacobi polynomial.

  3. The Bourgain-Tzafriri conjecture and concrete constructions of non-pavable projections

    CERN Document Server

    Casazza, Peter G; Mixon, Dustin G; Tremain, Janet C

    2010-01-01

    It is known that the Kadison-Singer Problem (KS) and the Paving Conjecture (PC) are equivalent to the Bourgain-Tzafriri Conjecture (BT). Also, it is known that (PC) fails for $2$-paving projections with constant diagonal $1/2$. But the proofs of this fact are existence proofs. We will use variations of the discrete Fourier Transform matrices to construct concrete examples of these projections and projections with constant diagonal $1/r$ which are not $r$-pavable in a very strong sense. In 1989, Bourgain and Tzafriri showed that the class of zero diagonal matrices with small entries (on the order of $\\le 1/log^{1+\\epsilon}n$, for an $n$-dimensional Hilbert space) are {\\em pavable}. It has always been assumed that this result also holds for the BT-Conjecture - although no one formally checked it. We will show that this is not the case. We will show that if the BT-Conjecture is true for vectors with small coefficients (on the order of $\\le C/\\sqrt{n}$) then the BT-Conjecture is true and hence KS and PC are true.

  4. Malaria Facts

    Science.gov (United States)

    ... CDC Malaria Branch clinician. malaria@cdc.gov Malaria Facts Recommend on Facebook Tweet Share Compartir Malaria in ... to determine definitively which species are involved. Other Facts Five times, the Nobel Prize in Physiology or ...

  5. Organ Facts

    Science.gov (United States)

    ... Lung Kidney Pancreas Kidney/Pancreas Liver Intestine Organ Facts Here you can find valuable information about organs ... Camps for kids Contacting my donor family Data Facts about living donation Financing a transplant Matching organs ...

  6. Kidney Facts

    Science.gov (United States)

    ... Lung Kidney Pancreas Kidney/Pancreas Liver Intestine Kidney Facts The kidneys are a pair of reddish-brown ... Camps for kids Contacting my donor family Data Facts about living donation Financing a transplant Matching organs ...

  7. Liver Facts

    Science.gov (United States)

    ... Lung Kidney Pancreas Kidney/Pancreas Liver Intestine Liver Facts How the Liver Works The liver is one ... Camps for kids Contacting my donor family Data Facts about living donation Financing a transplant Matching organs ...

  8. A holographic perspective on Gubser-Mitra conjecture

    CERN Document Server

    Buchel, A

    2005-01-01

    We point out an elementary thermodynamics fact that whenever the specific heat of a system is negative, the speed of sound in such a media is imaginary. The latter observation presents a proof of Gubser-Mitra conjecture on the relation between dynamical and thermodynamic instabilities for gravitational backgrounds with a translationary invariant horizon, provided such geometries can be interpreted as holographic duals to finite temperature gauge theories. It further identifies a tachyonic mode of the Gubser-Mitra instability (the lowest quasinormal mode of the corresponding horizon geometry) as a holographic dual to a sound wave in a dual gauge theory. As a specific example, we study sound wave propagation in Little String Theory (LST) compactified on a two-sphere. We find that at high energies (for temperatures close to the LST Hagedorn temperature) the speed of sound is purely imaginary. This implies that the lowest quasinormal mode of the finite temperature Maldacena-Nunez background is tachyonic.

  9. Searching Exact Solutions for Compact Stars in Braneworld: a conjecture

    CERN Document Server

    Ovalle, J

    2007-01-01

    In the context of the braneworld, a spherically symmetric, static and nonhomogeneous stellar distribution with local and non-local bulk terms is studied. Using a toy solution, it is shown how the general relativistic limit could be lost while a solution is being generated on the brane. The source of this problem is clearly identified and solved by a general solution where a constraint can be identified. This constraint is physically interpreted as a necessary condition to regain general relativity, and a particular solution for it is used to find an exact analytical internal solution to no-uniform stellar distributions on the brane. It is shown that such an exact solution is possible due to the fact that bulk corrections to pressure, density and a metric component are a null source of anisotropic effects on the brane. A conjecture is proposed about the possibility of finding physically relevant exact solutions to non-uniform stellar distributions on the brane.

  10. Transplantation of Local Nets and Geometric Modular Action on Robertson-Walker Space-Times

    CERN Document Server

    Buchholz, D; Summers, S J; Buchholz, Detlev; Mund, Jens; Summers, Stephen J.

    2001-01-01

    A novel method of transplanting algebras of observables from de Sitter space to a large class of Robertson-Walker space-times is exhibited. It allows one to establish the existence of an abundance of local nets on these spaces which comply with a recently proposed condition of geometric modular action. The corresponding modular symmetry groups appearing in these examples also satisfy a condition of modular stability, which has been suggested as a substitute for the requirement of positivity of the energy in Minkowski space. Moreover, they exemplify the conjecture that the modular symmetry groups are generically larger than the isometry and conformal groups of the underlying space-times.

  11. On the Mordell-Lang conjecture in positive characteristic

    CERN Document Server

    Rössler, Damian

    2011-01-01

    We describe an algebraic proof of a generalization of a part of the Tate-Voloch conjecture. Using jet spaces, the Mordell-Lang conjecture in positive characteristic (Hrushovski's theorem, see below) follows as a corollary.

  12. On the geometry of thin exceptional sets in Manin's conjecture

    DEFF Research Database (Denmark)

    Lehmann, Brian; Tanimoto, Sho

    2016-01-01

    Manin’s Conjecture predicts the rate of growth of rational points of a bounded height after removing those lying on an exceptional set. We study whether the exceptional set in Manin’s Conjecture is a thin set.......Manin’s Conjecture predicts the rate of growth of rational points of a bounded height after removing those lying on an exceptional set. We study whether the exceptional set in Manin’s Conjecture is a thin set....

  13. An improved Multiplicity Conjecture for codimension three Gorenstein algebras

    OpenAIRE

    2006-01-01

    The Multiplicity Conjecture is a deep problem relating the multiplicity (or degree) of a Cohen-Macaulay standard graded algebra with certain extremal graded Betti numbers in its minimal free resolution. In the case of level algebras of codimension three, Zanello has proposed a stronger conjecture. We prove this conjecture for the case of codimension three graded Gorenstein algebras.

  14. The volume conjecture and topological strings

    Energy Technology Data Exchange (ETDEWEB)

    Dijkgraaf, R. [Institute for Theoretical Physics, University of Amsterdam (Netherlands); Korteweg-de Vries Institute for Mathematics, University of Amsterdam (Netherlands); Fuji, H. [Department of Physics, Nagoya University (Japan)

    2009-09-15

    In this paper, we discuss a relation between Jones-Witten theory of knot invariants and topological open string theory on the basis of the volume conjecture. We find a similar Hamiltonian structure for both theories, and interpret the AJ conjecture as the D-module structure for a D-brane partition function. In order to verify our claim, we compute the free energy for the annulus contributions in the topological string using the Chern-Simons matrix model, and find that it coincides with the Reidemeister torsion in the case of the figure-eight knot complement and the SnapPea census manifold m009. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  15. Synchronous correlation matrices and Connes’ embedding conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Dykema, Kenneth J., E-mail: kdykema@math.tamu.edu [Department of Mathematics, Texas A& M University, College Station, Texas 77843-3368 (United States); Paulsen, Vern, E-mail: vern@math.uh.edu [Department of Mathematics, University of Houston, Houston, Texas 77204 (United States)

    2016-01-15

    In the work of Paulsen et al. [J. Funct. Anal. (in press); preprint arXiv:1407.6918], the concept of synchronous quantum correlation matrices was introduced and these were shown to correspond to traces on certain C*-algebras. In particular, synchronous correlation matrices arose in their study of various versions of quantum chromatic numbers of graphs and other quantum versions of graph theoretic parameters. In this paper, we develop these ideas further, focusing on the relations between synchronous correlation matrices and microstates. We prove that Connes’ embedding conjecture is equivalent to the equality of two families of synchronous quantum correlation matrices. We prove that if Connes’ embedding conjecture has a positive answer, then the tracial rank and projective rank are equal for every graph. We then apply these results to more general non-local games.

  16. The closed-universe recollapse conjecture

    Science.gov (United States)

    Barrow, John D.; Galloway, Gregory J.; Tipler, Frank J.

    1986-12-01

    It is widely believed that all expanding S3 closed universes that satisfy the standard energy conditions recollapse to a second singularity. The authors show that this is false even for Friedmann universes: they construct an ever-expanding S3 Friedmann universe in which the matter tensor satisfies the strong, weak and dominant energy conditions and the generic condition. The authors prove a general recollapse theorem for Friedmann universes: if the positive pressure criterion, dominant energy condition and matter regularity condition hold, then an S3 Friedmann universe must recollapse. The authors show that all known vacuum solutions with Cauchy surface topology S3 or S2×S1 recollapse, and they conjecture that this is a property of all vacuum solutions of Einstein's equations with such Cauchy surfaces. The authors consider a number of Kantowski-Sachs and Bianchi IX universes with various matter tensors, and formulate a new recollapse conjecture for matter-filled universes.

  17. The \\v{C}erny conjecture

    CERN Document Server

    Trahtman, A N

    2012-01-01

    A word w is called a synchronizing word of deterministic finite automaton (DFA) if w sends all states of the automaton to a unique state. In 1964, Jan Cerny discovered a sequence of an n-state complete DFA possessing a minimal synchronizing word of length (n-1)^2. The Cerny conjecture claims that it is also the upper bound on the length of such a word for a complete DFA. The problem has motivated great and constantly growing number of investigations and generalizations and together with the Road Coloring problem is considered as a most fascinating old problem in the theory of finite automata. The recently known upper bound for the length of the shortest synchronizing word is now equal to n(7n^2+6n-16)/48. An effort to prove the \\v{C}erny conjecture is presented.

  18. Conjectural Equilibrium in Water-filling Games

    CERN Document Server

    Su, Yi

    2008-01-01

    This paper considers a non-cooperative game in which competing users sharing a frequency-selective interference channel selfishly optimize their power allocation in order to improve their achievable rates. Previously, it was shown that a user having the knowledge of its opponents' channel state information can make foresighted decisions and substantially improve its performance compared with the case in which it deploys the conventional iterative water-filling algorithm, which does not exploit such knowledge. This paper discusses how a foresighted user can acquire this knowledge by modeling its experienced interference as a function of its own power allocation. To characterize the outcome of the multi-user interaction, the conjectural equilibrium is introduced, and the existence of this equilibrium for the investigated water-filling game is proved. Interestingly, both the Nash equilibrium and the Stackelberg equilibrium are shown to be special cases of the generalization of conjectural equilibrium. We develop...

  19. Gauge Identities and the Dirac Conjecture

    OpenAIRE

    Rothe, Heinz J.; Rothe, Klaus D.

    2004-01-01

    The gauge symmetries of a general dynamical system can be systematically obtained following either a Hamiltonean or a Lagrangean approach. In the former case, these symmetries are generated, according to Dirac's conjecture, by the first class constraints. In the latter approach such local symmetries are reflected in the existence of so called gauge identities. The connection between the two becomes apparent, if one works with a first order Lagrangean formulation. Our analysis applies to purel...

  20. Haglund's conjecture on 3-column Macdonald polynomials

    OpenAIRE

    Blasiak, Jonah

    2014-01-01

    We prove a positive combinatorial formula for the Schur expansion of LLT polynomials indexed by a 3-tuple of skew shapes. This verifies a conjecture of Haglund. The proof requires expressing a noncommutative Schur function as a positive sum of monomials in Lam's algebra of ribbon Schur operators. Combining this result with the expression of Haglund, Haiman, and Loehr for transformed Macdonald polynomials in terms of LLT polynomials then yields a positive combinatorial rule for transformed Mac...

  1. JACOBIAN CONJECTURE, TWO-DIMENSIONAL CASE

    Directory of Open Access Journals (Sweden)

    V. V. Starkov

    2016-12-01

    Full Text Available The Jacobian Conjecture was first formulated by O. Keller in 1939. In the modern form it supposes injectivity of the polynomial mapping f: R^n → R^n (C^n → C^n provided that jacobian J_f ≡ const ≠ 0. In this note we consider structure of polynomial mappings f that provide J_f ≡ const ≠ 0.

  2. Symplectic cobordisms and the strong Weinstein conjecture

    OpenAIRE

    GEIGES, Hansjörg; Zehmisch, Kai

    2011-01-01

    We study holomorphic spheres in certain symplectic cobordisms and derive information about periodic Reeb orbits in the concave end of these cobordisms from the non-compactness of the relevant moduli spaces. We use this to confirm the strong Weinstein conjecture (predicting the existence of null-homologous Reeb links) for various higher-dimensional contact manifolds, including contact type hypersurfaces in subcritical Stein manifolds and in some cotangent bundles. The quantitative character of...

  3. Proof of Ira Gessel's lattice path conjecture

    Science.gov (United States)

    Kauers, Manuel; Koutschan, Christoph; Zeilberger, Doron

    2009-01-01

    We present a computer-aided, yet fully rigorous, proof of Ira Gessel's tantalizingly simply stated conjecture that the number of ways of walking 2n steps in the region x + y ≥ 0,y ≥ 0 of the square lattice with unit steps in the east, west, north, and south directions, that start and end at the origin, equals 16n(5/6)n(1/2)n(5/3)n(2)n.

  4. Legendrian links, causality, and the Low conjecture

    CERN Document Server

    Chernov, Vladimir

    2008-01-01

    Let $(X^{m+1}, g)$ be a globally hyperbolic spacetime with Cauchy surface diffeomorphic to an open subset of $\\mathbb R^m$. The Legendrian Low conjecture formulated by Nat\\'ario and Tod says that two events $x,y\\in X$ are causally related if and only if the Legendrian link of spheres $\\mathfrak S_x, \\mathfrak S_y$ whose points are light geodesics passing through $x$ and $y$ is non-trivial in the contact manifold of all light geodesics in $X$. The Low conjecture says that for $m=2$ the events $x,y$ are causally related if and only if $\\mathfrak S_x, \\mathfrak S_y$ is non-trivial as a topological link. We prove the Low and the Legendrian Low conjectures. We also show that similar statements hold for any globally hyperbolic $(X, g)$ such that the universal cover of its Cauchy surface is diffeomorphic to an open domain of $\\mathbb R^m.$

  5. A unitary test of the Ratios Conjecture

    CERN Document Server

    Goes, John; Miller, Steven J; Montague, David; Ninsuwan, Kesinee; Peckner, Ryan; Pham, Thuy

    2009-01-01

    The Ratios Conjecture of Conrey, Farmer and Zirnbauer predicts the answers to numerous questions in number theory, ranging from n-level densities and correlations to mollifiers to moments and vanishing at the central point. The conjecture gives a recipe to generate these answers, which are believed to be correct up to square-root cancelation. These predictions have been verified, for suitably restricted test functions, for the 1-level density of orthogonal and symplectic families of L-functions. In this paper we verify the conjecture's predictions for the unitary family of all Dirichlet $L$-functions with prime conductor; we show square-root agreement between prediction and number theory if the support of the Fourier transform of the test function is in (-1,1), and for support up to (-2,2) we show agreement up to a power savings in the family's cardinality. The interesting feature in this family (which has not surfaced in previous investigations) is determining what is and what is not a diagonal term in the R...

  6. The weak gravity conjecture and scalar fields

    Science.gov (United States)

    Palti, Eran

    2017-08-01

    We propose a generalisation of the Weak Gravity Conjecture in the presence of scalar fields. The proposal is guided by properties of extremal black holes in N=2 supergravity, but can be understood more generally in terms of forbidding towers of stable gravitationally bound states. It amounts to the statement that there must exist a particle on which the gauge force acts more strongly than gravity and the scalar forces combined. We also propose that the scalar force itself should act on this particle stronger than gravity. This implies that generically the mass of this particle decreases exponentially as a function of the scalar field expectation value for super-Planckian variations, which is behaviour predicted by the Refined Swampland Conjecture. In the context of N=2 supergravity the Weak Gravity Conjecture bound can be tied to bounds on scalar field distances in field space. Guided by this, we present a general proof that for any linear combination of moduli in any Calabi-Yau compactification of string theory the proper field distance grows at best logarithmically with the moduli values for super-Planckian distances.

  7. Evidence for a sublattice weak gravity conjecture

    Science.gov (United States)

    Heidenreich, Ben; Reece, Matthew; Rudelius, Tom

    2017-08-01

    The Weak Gravity Conjecture postulates the existence of superextremal charged particles, i.e. those with mass smaller than or equal to their charge in Planck units. We present further evidence for our recent observation that in known examples a much stronger statement is true: an infinite tower of superextremal particles of different charges exists. We show that effective Kaluza-Klein field theories and perturbative string vacua respect the Sublattice Weak Gravity Conjecture, namely that a finite index sublattice of the full charge lattice exists with a superextremal particle at each site. In perturbative string theory we show that this follows from modular invariance. However, we present counterexamples to the stronger possibility that a superextremal particle exists at every lattice site, including an example in which the lightest charged particle is subextremal. The Sublattice Weak Gravity Conjecture has many implications both for abstract theories of quantum gravity and for real-world physics. For instance, it implies that if a gauge group with very small coupling e exists, then the fundamental gravitational cutoff energy of the theory is no higher than ˜ e 1/3 M Pl.

  8. Invariant measures and the soliton resolution conjecture

    CERN Document Server

    Chatterjee, Sourav

    2012-01-01

    The soliton resolution conjecture for the focusing nonlinear Schrodinger equation (NLS) is the vaguely worded claim that a global solution of the NLS, for generic initial data, will eventually resolve into a radiation component that disperses like a linear solution, plus a localized component that behaves like a soliton or multi-soliton solution. Considered to be one of the fundamental open problems in the area of nonlinear dispersive equations, this conjecture has eluded a proof or even a precise formulation till date. This paper proves a "statistical version" of this conjecture at mass-subcritical nonlinearity, in the following sense. The uniform probability distribution on the set of all functions with a given mass and energy, if such a thing existed, would be a natural invariant measure for the NLS flow and would reflect the long-term behavior for "generic initial data" with that mass and energy. Unfortunately, such a probability measure does not exist. We circumvent this problem by constructing a sequenc...

  9. The Tate conjecture for K3 surfaces over finite fields

    Science.gov (United States)

    Charles, François

    2013-10-01

    Artin's conjecture states that supersingular K3 surfaces over finite fields have Picard number 22. In this paper, we prove Artin's conjecture over fields of characteristic p>3. This implies Tate's conjecture for K3 surfaces over finite fields of characteristic p>3. Our results also yield the Tate conjecture for divisors on certain holomorphic symplectic varieties over finite fields, with some restrictions on the characteristic. As a consequence, we prove the Tate conjecture for cycles of codimension 2 on cubic fourfolds over finite fields of characteristic p>3.

  10. FellWalker - a Clump Identification Algorithm

    CERN Document Server

    Berry, David

    2014-01-01

    This paper describes the FellWalker algorithm, a watershed algorithm that segments a 1-, 2- or 3-dimensional array of data values into a set of disjoint clumps of emission, each containing a single significant peak. Pixels below a nominated constant data level are assumed to be background pixels and are not assigned to any clump. FellWalker is thus equivalent in purpose to the CLUMPFIND algorithm. However, unlike CLUMPFIND, which segments the array on the basis of a set of evenly-spaced contours and thus uses only a small fraction of the available data values, the FellWalker algorithm is based on a gradient-tracing scheme which uses all available data values. Comparisons of CLUMPFIND and FellWalker using a crowded field of artificial Gaussian clumps, all of equal peak value and width, suggest that the results produced by FellWalker are less dependent on specific parameter settings than are those of CLUMPFIND.

  11. Wet granular walkers and climbers

    Science.gov (United States)

    Khan, Zeina S.; Steinberger, Audrey; Seemann, Ralf; Herminghaus, Stephan

    2012-02-01

    We have observed that when a bidisperse mixture of glass beads is moistened by a fluid and shaken sinusoidally in a vertical container, small clusters of beads take off from the surface of the pile and rapidly climb up the container walls against gravity. These self-organized clus- ters are held together and against the wall by liquid capillary bridges, and are led by one large grain with one or more small grains trailing behind. When similar clusters are placed on a horizontally vibrating substrate they self-align and travel horizontally along the axis of vibration with a ratchet-like motion. We report a detailed experimental study performed for the simplest walker system consisting of one large and one small bead, and present a simple model that accounts for the observed behavior. Reference: Z.S. Khan et al.,New J. Phys 13, 053041 (2011).

  12. Cognition and Language: From Apprehension to Judgment -- Quantum Conjectures

    Science.gov (United States)

    Arecchi, F. T.

    2014-12-01

    We critically discuss the two moments of human cognition, namely, apprehension (A), whereby a coherent perception emerges from the recruitment of neuronal groups, and judgment (B), that entails the comparison of two apprehensions acquired at different times, coded in a suitable language and recalled by memory. (B) requires selfconsciousness, in so far as the agent who expresses the judgment must be aware that the two apprehensions are submitted to his/her own scrutiny and that it is his/her duty to extract a mutual relation. Since (B) lasts around 3 seconds, the semantic value of the pieces under comparison must be decided within this time. This implies a fast search of the memory contents. As a fact, exploring human subjects with sequences of simple words, we find evidence of a limited time window, corresponding to the memory retrieval of a linguistic item in order to match it with the next one in a text flow (be it literary, or musical,or figurative). Classifying the information content of spike trains, an uncertainty relation emerges between the bit size of a word and its duration. This uncertainty is ruled by a constant that can be given a numerical value and that has nothing to do with Planck's constant. A "quantum conjecture" in the above sense might explain the onset and decay of the memory window connecting successive pieces of a linguistic text. The conjecture here formulated is applicable to other reported evidences of quantum effects in human cognitive processes, so far lacking a plausible framework since no efforts to assign a quantum constant have been associated.

  13. Searching Exact Solutions for Compact Stars in Braneworld:. a Conjecture

    Science.gov (United States)

    Ovalle, J.

    In the context of the braneworld, a method to find consistent solutions to Einstein's field equations in the interior of a spherically symmetric, static and non-uniform stellar distribution with Weyl stresses is developed. This method, based on the fact that any braneworld stellar solution must have the general relativity solution as a limit, produces a constraint which reduces the degrees of freedom on the brane. Hence the nonlocality and non-closure of the braneworld equations can be overcome. The constraint found is physically interpreted as a necessary condition to regain general relativity, and a particular solution for it is used to find an exact and physically acceptable analytical internal solution to no-uniform stellar distributions on the brane. It is shown that such an exact solution is possible due to the fact that bulk corrections to pressure, density and a metric component are a null source of anisotropic effects on the brane. A conjecture is proposed regarding the possibility of finding physically relevant exact solutions to non-uniform stellar distributions on the brane.

  14. A Reduction of the Graph Reconstruction Conjecture

    Directory of Open Access Journals (Sweden)

    Monikandan S.

    2014-08-01

    Full Text Available A graph is said to be reconstructible if it is determined up to isomor- phism from the collection of all its one-vertex deleted unlabeled subgraphs. Reconstruction Conjecture (RC asserts that all graphs on at least three vertices are reconstructible. In this paper, we prove that interval-regular graphs and some new classes of graphs are reconstructible and show that RC is true if and only if all non-geodetic and non-interval-regular blocks G with diam(G = 2 or diam(Ḡ = diam(G = 3 are reconstructible

  15. Supercongruence conjectures of Rodriguez-Villegas

    CERN Document Server

    McCarthy, Dermot

    2009-01-01

    In examining the relationship between the number of points over $\\mathbb{F}_p$ on certain Calabi-Yau manifolds and hypergeometric series which correspond to a particular period of the manifold, Rodriguez-Villegas identified 22 possible supercongruences. We provide a framework of congruences covering all 22 cases. Using this framework we prove one of the outstanding supercongruence conjectures between a special value of a truncated ordinary hypergeometric series and the $p$-th Fourier coefficient of a modular form. In the course of this work we also establish two new binomial coefficient-harmonic sum identities.

  16. Non-Abelian Bosonization and Haldane's Conjecture

    CERN Document Server

    Cabra, D C; Von Reichenbach, M C

    1998-01-01

    We study the long wavelength limit of a spin S Heisenberg antiferromagnetic chain. The fermionic Lagrangian obtained corresponds to a perturbed level 2S SU(2) Wess-Zumino-Witten model. This effective theory is then mapped into a compact U(1) boson interacting with Z_{2S} parafermions. The analysis of this effective theory allows us to show that when S is an integer there is a mass gap to all excitations, whereas this gap vanishes in the half-odd-integer spin case. This gives a field theory treatment of the so-called Haldane's conjecture for arbitrary values of the spin S.

  17. Empowering Polynomial Theory Conjectures with Spreadsheets

    Directory of Open Access Journals (Sweden)

    Chris Petersdinh

    2017-06-01

    Full Text Available Polynomial functions and their properties are fundamental to algebra, calculus, and mathematical modeling. Students who do not have a strong understanding of the relationship between factoring and solving equations can have difficulty with optimization problems in calculus and solving application problems in any field. Understanding function transformations is important in trigonometry, the idea of the general antiderivative, and describing the geometry of a problem mathematically. This paper presents spreadsheet activities designed to bolster students' conceptualization of the factorization theorem for polynomials, complex zeros of polynomials, and function transformations. These activities were designed to use a constructivist approach involving student experimentation and conjectures.

  18. The Fibered Isomorphism Conjecture for Complex Manifolds

    Institute of Scientific and Technical Information of China (English)

    S. K. ROUSHON

    2007-01-01

    In this paper we show that the Fibered Isomorphism Conjecture of Farrell and Jones,corresponding to the stable topological pseudoisotopy functor, is true for the fundamental groups of a class of complex manifolds. A consequence of this result is that the Whitehead group, reduced projective class groups and the negative K-groups of the fundamental groups of these manifolds vanish whenever the fundamental group is torsion free. We also prove the same results for a class of real manifolds including a large class of 3-manifolds which has a finite sheeted cover fibering over the circle.

  19. Hamilton decompositions of regular expanders: a proof of Kelly's conjecture for large tournaments

    CERN Document Server

    Kühn, Daniela

    2012-01-01

    A long-standing conjecture of Kelly states that every regular tournament on n vertices can be decomposed into (n-1)/2 edge-disjoint Hamilton cycles. We prove this conjecture for large n. In fact, we prove a far more general result, based on our recent concept of robust expansion and a new method for decomposing graphs. We show that every sufficiently large regular digraph G on n vertices whose degree is linear in n and which is a robust outexpander has a decomposition into edge-disjoint Hamilton cycles. This enables us to obtain numerous further results, e.g. as a special case we confirm a conjecture of Erdos on packing Hamilton cycles in random tournaments. As corollaries to the main result, we also obtain several results on packing Hamilton cycles in undirected graphs, giving e.g. the best known result on a conjecture of Nash-Williams. We also apply our result to solve a problem on the domination ratio of the Asymmetric Travelling Salesman problem, which was raised e.g. by Glover and Punnen as well as Alon,...

  20. Drug Facts

    Medline Plus

    Full Text Available ... and Nicotine Facts Other Drugs of Abuse What is Addiction? What are some signs and symptoms of ... to Drugs? Does Addiction Run in Families? Why Is It So Hard to Quit Drugs? Effects of ...

  1. Drug Facts

    Medline Plus

    Full Text Available ... Nicotine Facts Other Drugs of Abuse What is Addiction? What are some signs and symptoms of someone ... use problem? How Does Drug Use Become an Addiction? What Makes Someone More Likely to Get Addicted ...

  2. Fact Sheets

    Science.gov (United States)

    ... Fact Sheets are available in both English and Spanish and can be downloaded for free. Currently available ... Antiviral Medications to Treat or Prevent Influenza (the Flu) PDF | Espanol PDF Apremilast (Otezla®) PDF | Espanol PDF ...

  3. Ferret facts

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This update functions to inform cooperators on the latest, most recent facts on the 1994 Montana Black-footed Ferret Reintroduction. This is a weekly update,...

  4. Drug Facts

    Medline Plus

    Full Text Available ... Nicotine Facts Other Drugs of Abuse What is Addiction? Do You or a Loved One Have a Drug Use Problem? Signs of Drug Use and Addiction How Does Drug Use Become Addiction? Addiction Risk ...

  5. Drug Facts

    Medline Plus

    Full Text Available ... The Link Between Drug Use and HIV/AIDS Recovery & Treatment Drug Treatment Facts Does Drug Treatment Work? ... and Family Can Help Find Treatment/Rehab Resources Prevent Drug Use Help Children and Teens Stay Drug- ...

  6. COMPUTER ANALYSIS OF ELECTROMOTORIC SWIVEL WALKER MOVEMENT

    Directory of Open Access Journals (Sweden)

    Jozef VARGA

    2016-12-01

    Full Text Available The first mechanical construction of swivel walker is from year 1963 and it was aimed for support movement of people with disabilities. This solution was very difficult and it was main reason for purpose of electromotoric module, which facilitates movement and reduce effort of people with disabilities. Therefore further research in this area are still provided. In this paper trajectory of swivel walker with electromotoric modules is described. To analyze the tilt and trajectory structure of the walker SolidWorks software was implemented.

  7. On the degenerated Arnold-Givental conjecture

    CERN Document Server

    Lu, Guangcun

    2008-01-01

    Let $(M, \\omega, \\tau)$ be a real symplectic manifold with nonempty and compact real part $L={\\rm Fix}(\\tau)$. We study the following degenerated version of the Arnold-Givental conjecture: $\\sharp(L\\cap\\phi(L))\\ge{\\rm Cuplength}_{\\F}(L)$ for any Hamiltonian diffeomorphism $\\phi:M\\to M$ and $\\F=\\Z, \\Z_2$. Suppose that $(M, \\omega)$ is geometrical bounded for some $J\\in{\\cal J}(M, \\omega)$ with $\\tau^\\ast J=-J$. We prove $\\sharp(L\\cap\\phi(L))\\ge {\\rm Cuplength}_{\\F}(L)$ for $\\F=\\Z_2$, and $\\F=\\Z_2, \\Z$ if $L$ is orientable, and for every Hamiltonian diffeomorphism $\\phi$ generated by a compactly supported Hamiltonian function whose Hofer norm is less than the minimal area of all nonconstant $J$-holomorphic spheres in $M$. In particular, this implies that the above degenerated Arnold-Givental conjecture holds on the K3-surfaces and closed negative monotone real symplectic manifolds of dimension $2n$ with either $n\\le 3$ or minimal Chern number $N\\ge n-2$. As consequences we get that every Hamiltonian diffeomorph...

  8. On the Kostant conjecture for Clifford algebra

    CERN Document Server

    Alekseev, Anton

    2011-01-01

    Let g be a complex simple Lie algebra, and h be a Cartan subalgebra. In the end of 1990s, B. Kostant defined two filtrations on h, one using the Clifford algebras and the odd analogue of the Harish-Chandra projection $hc: Cl(g) \\to Cl(h)$, and the other one using the canonical isomorphism $\\check{h} = h^*$ (here $\\check{h}$ is the Cartan subalgebra in the simple Lie algebra corresponding to the dual root system) and the adjoint action of the principal sl2-triple. Kostant conjectured that the two filtrations coincide. The two filtrations arise in very different contexts, and comparing them proved to be a difficult task. Y. Bazlov settled the conjecture for g of type A using explicit expressions for primitive invariants in the exterior algebra of g. Up to now this approach did not lead to a proof for all simple Lie algebras. Recently, A. Joseph proved that the second Kostant filtration coincides with the filtration on h induced by the generalized Harish-Chandra projection $(Ug \\otimes g)^g \\to Sh \\otimes h$ and...

  9. Dynamical Horizon Entropy Bound Conjecture in Loop Quantum Cosmology

    Institute of Scientific and Technical Information of China (English)

    李丽仿; 朱建阳

    2012-01-01

    The covariant entropy bound conjecture is an important hint for the quantum gravity, with several versions available in the literature. For cosmology, Ashtekar and Wilson-Ewing ever show the consistence between the loop gravity theory and one version of this conjecture. Recently, He and Zhang [J. High Energy Phys. 10 (2007) 077] proposed a version for the dynamical horizon of the universe, which validates the entropy bound conjecture for the cosmology filled with perfect fluid in the classical scenario when the universe is far away from the big bang singularity. However, their conjecture breaks down near big bang region. We examine this conjecture in the context of the loop quantum cosmology. With the example of photon gas, this conjecture is protected by the quantum geometry effects as expected.

  10. On Jannsen's conjecture for Hecke characters of imaginary quadratic fields

    CERN Document Server

    Bars, Francesc

    2007-01-01

    We present a collection of results on a conjecture of Jannsen about the $p$-adic realizations associated to Hecke characters over an imaginary quadratic field $K$ of class number 1. The conjecture is easy to check for Galois groups purely of local type. We prove the conjecture under a geometric regularity condition for the imaginary quadratic field $K$ at $p$, which is related to the property that a global Galois group is purely of local type. Without this regularity assumption at $p$, we present a review of the known situations in the critical case and in the non-critical case for the realizations associated to Hecke characters over $K$. We relate the conjecture to the non-vanishing of some concrete non-critical values of the associated $p$-adic $L$-function of the Hecke character. Finally, we prove that the conjecture follows from a general conjecture on Iwasawa theory for almost all Tate twists.

  11. The chaotic interaction of two walkers

    Science.gov (United States)

    Tadrist, Loic; Samara, Naresh; Schlagheck, Peter; Gilet, Tristan

    2016-11-01

    A droplet bouncing on a vertically vibrated bath may be propelled horizontally by the Faraday waves that it generates at each rebound. This association of a wave and a particle is called a walker. Ten years ago, Yves Couder and co-workers noted that the dynamical encounter of two walkers may lead to either scattered trajectories or orbital motion. In this work, we investigate the interaction of two walkers more systematically. The walkers are launched towards each other with finely controlled initial conditions. Output trajectories are classified in four types: scattering, orbiting, wandering and complex. The interaction appears stochastic: the same set of initial parameters (to the measurement accuracy) can produce different outputs. Our analysis of the underlying chaos provides new insights on the stochastic nature of this experiment. This work is supported by the ARC Quandrops of the Wallonia-Brussels Federation.

  12. Misconceptions in Halliday, Resnick and Walker's textbook

    CERN Document Server

    Berman, M S

    2005-01-01

    Eleven misconceptions involving Relativity, Gravitation and Cosmology are exposed, that appeared in the textbook: Fundamentals of Physics, 7th Edition, by Halliday, Resnick and Walker, Willey, New York (2005), or other companion textbooks.

  13. Snack, Facts

    Science.gov (United States)

    Smith, Suzanne M.

    2005-01-01

    The American diet has undergone substantial changes, a fact that has negatively impacted the dental health of children. Primary prevention is the ideal method to address the current increased incidence of tooth decay. Educating kids, and their parents, about the qualities of snacks as well as the role of frequency of snacking could help to reduce…

  14. Reptile Facts.

    Science.gov (United States)

    Steinheimer, Margaret

    1993-01-01

    Describes an award-winning bulletin board for introducing a unit on reptiles. This interactive bulletin board contains fun facts and counters common misconceptions about reptiles. Twelve true-false statements are hidden behind pull-up flaps. Four pictures ask students to identify the difference between often-confused animals. (PR)

  15. Earthquake Facts

    Science.gov (United States)

    Jump to Navigation Earthquake Facts The largest recorded earthquake in the United States was a magnitude 9.2 that struck Prince William Sound, ... we know, there is no such thing as "earthquake weather" . Statistically, there is an equal distribution of ...

  16. The FZZ-Duality Conjecture - A Proof

    CERN Document Server

    Hikida, Yasuaki

    2009-01-01

    We prove that the cigar conformal field theory is dual to the Sine-Liouville model, as conjectured originally by Fateev, Zamolodchikov and Zamolodchikov. Since both models possess the same chiral algebra, our task is to show that correlations of all tachyon vertex operators agree. We accomplish this goal through an off-critical version of the geometric Langlands duality for sl(2). More explicitly, we combine the well-known self-duality of Liouville theory with an intriguing correspondence between the cigar and Liouville field theory. The latter is derived through a path integral treatment. After a very detailed discussion of genus zero amplitudes, we extend the duality to arbitrary closed surfaces.

  17. On a Conjecture of M. J. Dunwoody

    Institute of Scientific and Technical Information of China (English)

    Alberto Cavicchioli; Beatrice Ruini; Fulvia Spaggiari

    2001-01-01

    We deal with three combinatorial representations of closed orientable 3-manifolds, i.e., Heegaard diagrams, branched coverings, and crystallizations (a special class of pseudo-graphs endowed with proper edge-colorings). Exploring the connections between those theories, we prove the validity of a conjecture,stated by Dunwoody in [14], concerning the class of closed orientable 3-manifolds represented by symmetric Heegaard diagrams. As a consequence, we classify the topological and geometric structures of many interesting classes of cyclic branched coverings of (hyperbolic) knots encoded by cyclic presentations of groups. In all cases, we show that the polynomial associated with the cyclic presentation coincides (up to a multiplicative unit) with the Alexander polynomial of the considered knot. Finally, we include a partial output of a computer program which generates symmetric Heegaard diagrams of cyclic branched coverings of 3-bridge knots up to nine crossings.

  18. The FZZ-duality conjecture. A proof

    Energy Technology Data Exchange (ETDEWEB)

    Hikida, Y. [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Schomerus, V. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2008-05-15

    We prove that the cigar conformal field theory is dual to the Sine-Liouville model, as conjectured originally by Fateev, Zamolodchikov and Zamolodchikov. Since both models possess the same chiral algebra, our task is to show that correlations of all tachyon vertex operators agree. We accomplish this goal through an off-critical version of the geometric Langlands duality for sl(2). More explicitly, we combine the well-known self-duality of Liouville theory with an intriguing correspondence between the cigar and Liouville field theory. The latter is derived through a path integral treatment. After a very detailed discussion of genus zero amplitudes, we extend the duality to arbitrary closed surfaces. (orig.)

  19. Weak Gravity Conjecture and Extremal Black Holes

    CERN Document Server

    Cottrell, William; Soler, Pablo

    2016-01-01

    Motivated by the desire to improve our understanding of the Weak Gravity Conjecture, we compute the one-loop correction of charged particles to the geometry and entropy of extremal black holes in 4d. Contrary to expectations, we find that loops of massive charged particles can radically alter the classical black hole geometry and that fermion loops provide evidence for the necessity of the `magnetic' WGC cutoff. The corrections are reduced when supersymmetry is present, and disappear in ${\\cal N}=4$ supergravity. We further provide some speculative arguments that in a theory with only sub-extremal particles, classical Reisner-Nordstrom black holes actually possess an infinite microcanonical entropy, though only a finite amount is visible to an external observer.

  20. The Weak Gravity Conjecture in three dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Montero, Miguel [Departamento de Física Teórica, Facultad de Ciencias,Universidad Autónoma de Madrid,Calle Francisco Tomás y Valiente 7, 28049 Madrid (Spain); Instituto de Física Teórica IFT-UAM/CSIC, Campus de Cantoblanco,C/ Nicolás Cabrera 13-15, 28049 Madrid (Spain); Shiu, Gary; Soler, Pablo [Department of Physics, University of Wisconsin-Madison,1150 University Ave, Madison, WI 53706 (United States); Department of Physics & Institute for Advanced Study,Hong Kong University of Science and Technology,Lo Ka Chung Building, Lee Shau Kee Campus, Clear Water Bay (Hong Kong)

    2016-10-28

    We study weakly coupled U(1) theories in AdS{sub 3}, their associated charged BTZ solutions, and their charged spectra. We find that modular invariance of the holographic dual two-dimensional CFT and compactness of the gauge group together imply the existence of charged operators with conformal dimension significantly below the black hole threshold. We regard this as a form of the Weak Gravity Conjecture (WGC) in three dimensions. We also explore the constraints posed by modular invariance on a particular discrete ℤ{sub N} symmetry which arises in our discussion. In this case, modular invariance does not guarantee the existence of light ℤ{sub N}-charged states. We also highlight the differences between our discussion and the usual heuristic arguments for the WGC based on black hole remnants.

  1. The Weak Gravity Conjecture in three dimensions

    CERN Document Server

    Montero, Miguel; Soler, Pablo

    2016-01-01

    We study weakly coupled $U(1)$ theories in $AdS_3$, their associated charged BTZ solutions, and their charged spectra. We find that modular invariance of the holographic dual two-dimensional CFT and compactness of the gauge group together imply the existence of charged operators with conformal dimension significantly below the black hole threshold. We regard this as a form of the Weak Gravity Conjecture (WGC) in three dimensions. We also explore the constraints posed by modular invariance on a particular discrete $\\mathbb{Z}_N$ symmetry which arises in our discussion. In this case, modular invariance does not guarantee the existence of light $\\mathbb{Z}_N$-charged states. We also highlight the differences between our discussion and the usual heuristic arguments for the WGC based on black hole remnants.

  2. A conjecture on the norm of Lyapunov mapping

    Institute of Scientific and Technical Information of China (English)

    Daizhan CHENG; Yahong ZHU; Hongsheng QI

    2009-01-01

    A conjecture that the norm of Lyapunov mapping LA equals to its restriction to the symmetric set,S,i.e.,‖LA‖ = ‖LA |s‖ was proposed in [1].In this paper,a method for numerical testing is provided first.Then,some recent progress on this conjecture is presented.

  3. Note on a Conjecture of Gopakumar-Vafa

    Institute of Scientific and Technical Information of China (English)

    Jun LI; Baosen WU

    2006-01-01

    We rephrase the Gopakumar-Vafa conjecture on genus zero Gromov-Witten invariants of Calabi-Yau threefolds in terms of the virtual degree of the moduli of pure dimension one stable sheaves and investigate the conjecture for K3 fibred local Calabi-Yau threefolds.

  4. On a conjecture about enumerating $(2+2)$-free posets

    CERN Document Server

    Yan, Sherry H F

    2010-01-01

    Recently, Kitaev and Remmel posed a conjecture concerning the generating function for the number of unlabeled $(2+2)$-free posets with respect to number of elements and number of minimal elements. In this paper, we present a combinatorial proof of this conjecture.

  5. The quantum unique ergodicity conjecture for thin sets

    OpenAIRE

    Young, Matthew P

    2013-01-01

    We consider some analogs of the quantum unique ergodicity conjecture for geodesics, horocycles, or ``shrinking'' families of sets. In particular, we prove the analog of the QUE conjecture for Eisenstein series restricted to the infinite geodesic connecting 0 and infinity inside the modular surface.

  6. Quantum hoop conjecture and a natural cutoff for vacuum energy

    CERN Document Server

    Yang, Rong-Jia

    2015-01-01

    We propose here a quantum hoop conjecture which states: the de Broglie wavelength of a quantum system can not be infinitely small, otherwise it will collapse into a quantum black hole. Based on this conjecture, we find an upper bound for the wave number of a particle, which offers a natural cutoff for the vacuum energy.

  7. On Erdős–Wood’s conjecture

    Indian Academy of Sciences (India)

    S Subburam; R Thangadurai

    2015-05-01

    In this article, we prove that infinite number of integers satsify Erdős–Woods conjecture. Moreover, it follows that the number of natural numbers ≤ satisfies Erdős–Woods conjecture with = 2 is at least /(log ) for some positive constant > 2.

  8. A B\\"ocherer-Type Conjecture for Paramodular Forms

    CERN Document Server

    Ryan, Nathan C

    2010-01-01

    In the 1980s B\\"ocherer formulated a conjecture relating the central value of the quadratic twists of the spinor L-function attached to a Siegel modular form F to the coefficients of F . He proved the conjecture when F is a Saito-Kurokawa lift. Later Kohnen and Kuss gave numerical evidence for the conjecture in the case when F is a rational eigenform that is not a Saito-Kurokawa lift. In this paper we develop a conjecture relating the central value of the quadratic twists of the spinor L-function attached to a paramodular form and the coefficients of the form. We prove the conjecture in the case when the form is a Gritsenko lift and provide numerical evidence when it is not a lift.

  9. A remark on the Generalized Hodge Conjecture

    CERN Document Server

    Portelli, Dario

    2010-01-01

    Let X be a smooth, projective variety over the field of complex numbers. On the space H of its rational cohomology of degree i we have the arithmetic filtration F^p. On the other hand, on the space of cohomology of degree i of X with complex coefficients we have the Hodge filtration G^p. It is well known that F^p is contained in the intersection of G^p with H, and that, in general, this inclusion is strict. In this paper we propose a natural substitute S^p for the Hodge filtration space G^p such that the intersection of S^p with H is the space F^p of the arithmetic filtration. In particular, S^p is a complex subspace of G^p. This result leaves untouched Grothendieck's Generalized Hodge Conjecture. But the method used here to construct algebraic supports for suitable cohomology classes seems to me of some interest. The main technical tool is the use of semi-algebraic sets, which are available by the triangulation of complex projective algebraic varieties.

  10. Relaxion monodromy and the Weak Gravity Conjecture

    Science.gov (United States)

    Ibáñez, L. E.; Montero, M.; Uranga, A. M.; Valenzuela, I.

    2016-04-01

    The recently proposed relaxion models require extremely large trans-Planckian axion excursions as well as a potential explicitly violating the axion shift symmetry. The latter property is however inconsistent with the axion periodicity, which corresponds to a gauged discrete shift symmetry. A way to make things consistent is to use monodromy, i.e. both the axion and the potential parameters transform under the discrete shift symmetry. The structure is better described in terms of a 3-form field C μνρ coupling to the SM Higgs through its field strength F 4. The 4-form also couples linearly to the relaxion, in the Kaloper-Sorbo fashion. The extremely small relaxion-Higgs coupling arises in a see-saw fashion as g ≃ F 4 /f , with f being the axion decay constant. We discuss constraints on this type of constructions from membrane nucleation and the Weak Gravity Conjecture. The latter requires the existence of membranes, whose too fast nucleation could in principle drive the theory out of control, unless the cut-off scale is lowered. This allows to rule out the simplest models with the QCD axion as relaxion candidate on purely theoretical grounds. We also discuss possible avenues to embed this structure into string theory.

  11. Tests of conjectures on multiple Watson values

    CERN Document Server

    Broadhurst, David

    2015-01-01

    I define multiple Watson values (MWVs) as iterated integrals, on the interval $x\\in[0,1]$, of the 6 differential forms $A=d\\log(x)$, $B=-d\\log(1-x)$, $T=-d\\log(1-z_1x)$, $U=-d\\log(1-z_2x)$, $V=-d\\log(1-z_3x)$ and $W=-d\\log(1-z_4x)$, where $z_1=\\gamma^2$, $z_2=\\gamma/(1+\\gamma)$, $z_3=\\gamma^2/(1-\\gamma)$ and $z_4=\\gamma=2\\sin(\\pi/14)$ solves the cubic $(1-\\gamma^2)(1-\\gamma)=\\gamma$. Following a suggestion by Pierre Deligne, I conjecture that the dimension of the space of ${\\mathbb Z}$-linearly independent MWVs of weight $w$ is the number $D_w$ generated by $1/(1-2x-x^2-x^3)=1+\\sum_{w>0}D_w x^w$. This agrees with 6639 integer relation searches, of dimensions up to $D_5+1=85$, performed at 2000-digit precision, for $w<6$.

  12. Weak gravity conjecture and effective field theory

    Science.gov (United States)

    Saraswat, Prashant

    2017-01-01

    The weak gravity conjecture (WGC) is a proposed constraint on theories with gauge fields and gravity, requiring the existence of light charged particles and/or imposing an upper bound on the field theory cutoff Λ . If taken as a consistency requirement for effective field theories (EFTs), it rules out possibilities for model building including some models of inflation. I demonstrate simple models which satisfy all forms of the WGC, but which through Higgsing of the original gauge fields produce low-energy EFTs with gauge forces that badly violate the WGC. These models illustrate specific loopholes in arguments that motivate the WGC from a bottom-up perspective; for example the arguments based on magnetic monopoles are evaded when the magnetic confinement that occurs in a Higgs phase is accounted for. This indicates that the WGC should not be taken as a veto on EFTs, even if it turns out to be a robust property of UV quantum gravity theories. However, if the latter is true, then parametric violation of the WGC at low energy comes at the cost of nonminimal field content in the UV. I propose that only a very weak constraint is applicable to EFTs, Λ ≲(log 1/g )-1 /2Mpl , where g is the gauge coupling, motivated by entropy bounds. Remarkably, EFTs produced by Higgsing a theory that satisfies the WGC can saturate but not violate this bound.

  13. Empirical Limits on the Russell Conjecture

    CERN Document Server

    Reddick, Rachel

    2013-01-01

    The Russell Conjecture states that there is an unproven possibility of small (<1 m) hollow heat-resistant objects (HoHOs) in Earth orbit or otherwise present in the inner solar system or asteroid belt. While such objects are not the current target of any ongoing searches, we can place stringent limits on their presence using current optical and infrared surveys. The high albedo of HoHOs partially compensates for their small size. As such, we find that no HoHOs greater than 10 cm in radius to a distance of at least 30,000 km, by the Air Force Space Surveillance System. Objects of that size in a stable orbit at 384,000 km (the Earth-Moon distance) may be detected and confirmed by more infrequent, deeper sweeps of the same system. However, it remains possible for undetected HoHOs to exist in near-Earth or Martian orbit. We discuss the prospects of finding such HoHOs in the near future with new telescopes such as LSST.

  14. Planckian axions and the Weak Gravity Conjecture

    Science.gov (United States)

    Bachlechner, Thomas C.; Long, Cody; McAllister, Liam

    2016-01-01

    Several recent works [1-3] have claimed that the Weak Gravity Conjecture (WGC) excludes super-Planckian displacements of axion fields, and hence large-field axion inflation, in the absence of monodromy. We argue that in theories with N ≫ 1 axions, super-Planckian axion diameters D are readily allowed by the WGC. We clarify the non-trivial relationship between the kinetic matrix K — unambiguously defined by its form in a Minkowski-reduced basis — and the diameter of the axion fundamental domain, emphasizing that in general the diameter is not solely determined by the eigenvalues f 1 2 ≤ ṡ ṡ ṡ ≤ f N 2 of K: the orientations of the eigenvectors with respect to the identifications imposed by instantons must be incorporated. In particular, even if one were to impose the condition f N M pl does not immediately imply the existence of unsuppressed higher harmonic contributions to the potential. Finally, we argue that in effective axion-gravity theories, the zero-form version of the WGC can be satisfied by gravitational instantons that make negligible contributions to the potential.

  15. Planckian Axions and the Weak Gravity Conjecture

    CERN Document Server

    Bachlechner, Thomas C; McAllister, Liam

    2015-01-01

    Several recent works have claimed that the Weak Gravity Conjecture (WGC) excludes super-Planckian displacements of axion fields, and hence large-field axion inflation, in the absence of monodromy. We argue that in theories with $N\\gg1$ axions, super-Planckian axion diameters $\\cal{D}$ are readily allowed by the WGC. We clarify the nontrivial relationship between the kinetic matrix $K$ --- unambiguously defined by its form in a Minkowski-reduced basis --- and the diameter of the axion fundamental domain, emphasizing that in general the diameter is not solely determined by the eigenvalues $f_1^2 \\le ... \\le f_N^2$ of $K$: the orientations of the eigenvectors with respect to the identifications imposed by instantons must be incorporated. In particular, even if one were to impose the condition $f_NM_{pl}$ does not immediately imply the existence of unsuppressed higher harmonic contributions to the potential. Finally, we argue that in effective axion-gravity theories, the zero-form version of the WGC can be satisf...

  16. Contractor renormalization group and the Haldane conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Marvin

    2001-05-01

    The contractor renormalization group formalism (CORE) is a real-space renormalization group method which is the Hamiltonian analogue of the Wilson exact renormalization group equations. In an earlier paper [Phys. Rev. D 61, 034505 (2000)] I showed that the CORE method could be used to map a theory of free quarks and quarks interacting with gluons into a generalized frustrated Heisenberg antiferromagnet (HAF) and proposed using CORE methods to study these theories. Since generalizations of HAF's exhibit all sorts of subtle behavior which, from a continuum point of view, are related to topological properties of the theory, it is important to know that CORE can be used to extract this physics. In this paper I show that despite the folklore which asserts that all real-space renormalization group schemes are necessarily inaccurate, simple CORE computations can give highly accurate results even if one only keeps a small number of states per block and a few terms in the cluster expansion. In addition I argue that even very simple CORE computations give a much better qualitative understanding of the physics than naive renormalization group methods. In particular I show that the simplest CORE computation yields a first-principles understanding of how the famous Haldane conjecture works for the case of the spin-1/2 and spin-1 HAF.

  17. Soils of Walker Branch Watershed

    Energy Technology Data Exchange (ETDEWEB)

    Lietzke, D.A.

    1994-01-01

    The soil survey of Walker Branch Watershed (WBW) utilized the most up-to-date knowledge of soils, geology, and geohydrology in building the soils data base needed to reinterpret past research and to begin new research in the watershed. The soils of WBW were also compared with soils mapped elsewhere along Chestnut Ridge on the Oak Ridge Reservation to (1) establish whether knowledge obtained elsewhere could be used within the watershed, (2) determine whether there were any soils restricted to the watershed, and (3) evaluate geologic formation lateral variability. Soils, surficial geology, and geomorphology were mapped at a scale of 1:1200 using a paper base map having 2-ft contour intervals. Most of the contours seemed to reasonably represent actual landform configurations, except for dense wooded areas. For example, the very large dolines or sinkholes were shown on the contour base map, but numerous smaller ones were not. In addition, small drainageways and gullies were often not shown. These often small but important features were located approximately as soil mapping progressed. WBW is underlain by dolostones of the Knox Group, but only a very small part of the surface area contains outcroppings of rock and most outcrops were located in the lower part. Soil mapping revealed the presence of both ancient alluvium and ancient colluvium deposits, not recognized in previous soil surveys, that have been preserved in high-elevation stable portions of present-day landforms. An erosional geomorphic process of topographic inversion requiring several millions of years within the Pleistocene is necessary to bring about the degree of inversion that is expressed in the watershed. Indeed, some of these ancient alluvial and colluvial remnants may date back into the Tertiary. Also evident in the watershed, and preserved in the broad, nearly level bottoms of dolines, are multiple deposits of silty material either devoid or nearly devoid of coarse fragments. Recent research

  18. Constraints on hypothetical counterexamples to the Casas-Alvero conjecture

    CERN Document Server

    Laterveer, Robert

    2012-01-01

    The Casas-Alvero conjecture states: if a complex univariate polynomial has a common root with each of its derivatives, then it has a unique root. We show that hypothetical counterexamples must have at least 5 different roots. The first case where the conjecture is not known is in degree 12. We study the case of degree 12, and more generally degree p+1, where p is a prime number. While we don't come closing to solving the conjecture in degree 12, we present several further constraints that counterexamples would have to satisfy.

  19. Aspects of Quantum Mathematics Hitchin Connections and AJ Conjectures

    DEFF Research Database (Denmark)

    Lauridsen, Magnus Roed

    We discuss two different areas related to -dimensional Topological Quantum Field Theory, namely geometric quantization and the AJ-conjecture in knot theory. First, we construct a Hitchin connection in geometric quantization with metaplectic correction of symplectic manifolds, and compare...... it to previous constructions. Second, we review the AJ-conjecture in knot theory, relating the coloured Jones polynomial and the A-polynomial. We reformulate this conjecture geometrically, drawing on geometric quantization of moduli spaces. Last, we use Faddeev's quantum dilogarithm to describe the asymptotic...

  20. Electromagnetic Radiation in Multiply Connected Robertson-Walker Cosmologies

    CERN Document Server

    Tomaschitz, R

    1993-01-01

    Maxwell's equations on a topologically nontrivial cosmological background are studied. The cosmology is locally determined by a Robertson-Walker line element, but the spacelike slices are open hyperbolic manifolds, whose topology and geometry may vary in time. In this context the spectral resolution of Maxwell's equations in terms of horospherical elementary waves generated at infinity of hyperbolic space is given. The wave fronts are orthogonal to bundles of unstable geodesic rays, and the eikonal of geometric optics appears just as the phase of the horospherical waves. This fact is used to attach to the unstable geodesic rays a quantum mechanical momentum. In doing so the quantized energy-momentum tensor of the radiation field is constructed in a geometrically and dynamically transparent way, without appealing to the intricacies of the second quantization. In particular Planck's radiation formula, and the bearing of the multiply connected topology on the fluctuations in the temperature of the background rad...

  1. Classical and Quantum Dispersion in Robertson-Walker Cosmologies

    CERN Document Server

    Tomaschitz, R

    1993-01-01

    The instability of world lines in Robertson-Walker universes of negative spatial curvature is investigated. A probabilistic description of this instability, similar to the Liouville equation, is developed, but in a manifestly covariant, non-Hamiltonian form. To achieve this the concept of a horospherical geodesic flow of expanding bundles of parallel world lines is introduced. An invariant measure and a covariant evolution equation for the probability density on which this flow acts is constructed. The orthogonal surfaces to these bundles of trajectories are horospheres, closed surfaces in three-space, touching the boundary at infinity of hyperbolic space, where the flow lines emerge. These horospheres are just the wave fronts of spherical waves, which constitute a complete set of eigenfunctions of the Klein-Gordon equation. This fact suggests that the evolution of the quantum mechanical density with the classical one be compared, and asymptotic identity in the asymptotically flat region is found. This leads,...

  2. Proof of Murphy-Cohen Conjecture on One-Dimensional Hard Ball Systems

    Institute of Scientific and Technical Information of China (English)

    Lizhou CHEN

    2007-01-01

    We prove the Murphy and Cohen's conjecture that the maximum number of collisions of n+1 elastic particles moving freely on a line is n(n+1)/2 if no interior particle has mass less than the arithmetic mean of the masses of its immediate neighbors.In fact,we prove the stronger result that,for the same conclusion,the condition that no interior particle has mass less than the geometric mean,rather than the arithmetic mean,of the masses of its immediate neighbors suffices.

  3. Digital elevation model of Walker Lake, West-Central Nevada

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Walker Lake lies within a topographically closed basin in west-central Nevada and is the terminus of the Walker River. Accurately determining the bathymetry and...

  4. DNA Walker-Regulated Cancer Cell Growth Inhibition.

    Science.gov (United States)

    Li, Feiran; Cha, Tae-Gon; Pan, Jing; Ozcelikkale, Altug; Han, Bumsoo; Choi, Jong Hyun

    2016-06-16

    We demonstrate a DNAzyme-based walker system as a controlled oligonucleotide drug AS1411 release platform for breast cancer treatment. In this system, AS1411 strands are released from fuel strands as a walker moves along its carbon nanotube track. The release rate and amount of anticancer oligonucleotides are controlled by the walker operation. With a walker system embedded within the collagen extracellular matrix, we show that this drug release system can be used for in situ cancer cell growth inhibition.

  5. A Few Hard Facts and a Great Deal of Conjecture: Catholic Schools in England

    Science.gov (United States)

    Morris, Andrew B.

    2009-01-01

    This paper presents new evidence from national contextualized school performance data showing that, after taking into account those factors known to affect pupil achievement, state-maintained Catholic schools in England appear to be more academically effective than similar non-Catholic institutions. Using an American analysis of the nature of…

  6. C-Reactive Protein (CRP and Autoimmune Disease: Facts and Conjectures

    Directory of Open Access Journals (Sweden)

    Alexander J. Szalai

    2004-01-01

    Full Text Available C-reactive protein (CRP is a blood component comprised of five identical subunits with a combined molecular mass of 110 kDa; in the presence of Ca++ it binds phosphocholine (PC with high affinity. Ligand-bound CRP activates complement and the protein reportedly binds various Fc receptors. Coincident with a now decade-long resurgence in clinical interest in associations of CRP with disease, our laboratory has been investigating the biology of CRP in vivo using human CRP transgenic mice (CRPtg. At that time we confirmed that CRP affects a host defense function mediated at least in part through the elimination of pathogens. Less appreciated and not as well understood as CRP's ability to bind antigen and aid in the elimination of microbes, is its known ability to bind autoantigens and presumed capacity to promote clearance of apoptotic cells. These latter properties of CRP have long been suspected to contribute to homeostasis and to autoimmune disease. In this article we review and update the evidence generated in CRPtg by our group and in vitro by others' that indicates CRP is more than just an antimicrobial molecule and convenient marker of inflammation - rather, it protects against autoimmunity. A mechanistic hypothesis is presented to account for this cause-and-effect relationship.

  7. Improving the Nomad microscopic walker model

    NARCIS (Netherlands)

    Campanella, M.C.

    2010-01-01

    This paper presents the results of two calibration efforts and improvements of the Nomad microscopic walker model. Each calibration consisted in comparing the outcome of 19 sets of model parameters with results from laboratory experiments. Three different flows were used in the calibrations: bidirec

  8. 75 FR 51178 - Safety Standard for Infant Walkers; Correction

    Science.gov (United States)

    2010-08-19

    ... statements on walkers with parking brakes. DATES: Effective on December 21, 2010. FOR FURTHER INFORMATION.... 1216.2(b)(21)(i), concerning a warning statement for walkers with parking brakes omitted a phrase indicating that the warning is only required for walkers that have parking brakes. The preamble to the...

  9. 78 FR 48301 - Establishment of Class E Airspace; Walker, MN

    Science.gov (United States)

    2013-08-08

    ... Federal Aviation Administration 14 CFR Part 71 Establishment of Class E Airspace; Walker, MN AGENCY... airspace at Walker, MN. Controlled airspace is necessary to accommodate new Area Navigation (RNAV) Standard... Federal Register a notice of proposed rulemaking (NPRM) to establish Class E airspace for the Walker, MN...

  10. Walker Calhoun: Cherokee Song and Dance Man. Interview.

    Science.gov (United States)

    Olson, Ted

    1995-01-01

    Born in 1918, the youngest of 12 children, Walker Calhoun describes growing up on the Cherokee Reservation in North Carolina. The schools turned the Cherokee against their old ways, but Walker learned many old songs and dances from his uncle, Will West. Since retirement, Walker has taught the dances and songs to children. His material has been…

  11. On the generalized lower bound conjecture for polytopes and spheres

    CERN Document Server

    Murai, Satoshi

    2012-01-01

    In 1971, McMullen and Walkup posed the following conjecture, which is called the generalized lower bound conjecture (GLBC): If $P$ is a simplicial $d$-polytope then its $h$-vector $(h_0,h_1,...,h_d)$ satisfies $h_0 \\leq h_1 \\leq ... \\leq h_{\\lfloor d/2 \\rfloor}$. Moreover, if $h_{r-1}=h_r$ for some $r \\leq d/2$ then $P$ can be triangulated without introducing simplices of dimension $\\leq d-r$. The first part of the conjecture was solved by Stanley in 1980 using the Hard Lefschetz theorem for toric varieties. In this paper, we give a proof of the remaining part of the conjecture. In addition, we generalize this property to a certain class of simplicial spheres, namely those admitting the weak Lefschetz property.

  12. An algebro-geometric proof of Witten's conjecture

    Science.gov (United States)

    Kazarian, M. E.; Lando, S. K.

    2007-10-01

    We present a new proof of Witten's conjecture. The proof is based on the analysis of the relationship between intersection indices on moduli spaces of complex curves and Hurwitz numbers enumerating ramified coverings of the 2 -sphere.

  13. On conjectures of Minkowski and Woods for $n = 9$

    Indian Academy of Sciences (India)

    LEETIKA KATHURIA; MADHU RAKA

    2016-10-01

    Let $\\mathbb{R}^n$ be the $n$-dimensional Euclidean space with $O$ as the origin. Let $\\wedge$ be a lattice of determinant 1 such that there is a sphere $\\mid X \\mid \\lt R$ which contains no point of $\\wedge$ other than $O$ and has $n$ linearly independent points of $\\wedge$ on its boundary. A well known conjecture in the geometry of numbers asserts that any closed sphere in $\\mathbb{R}^n$ of radius $\\sqrt{n/4}$ contains a point of $\\wedge$. This is known to be true for $n\\leq 8$. Here we prove a more general conjecture of Woods for $n = 9$ from which this conjecture follows in $\\mathbb{R}^9$. Together with a result of McMullen (J. Amer. Math. Soc. 18 (2005) 711–734), the long standing conjecture of Minkowski follows for $n = 9$.

  14. Berry{close_quote}s conjecture and information theory

    Energy Technology Data Exchange (ETDEWEB)

    Jarzynski, C. [Theoretical Astrophysics, T-6, MS B288, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1997-08-01

    It is shown that, by applying a principle of information theory, one obtains Berry{close_quote}s conjecture regarding the high-lying quantal energy eigenstates of classically chaotic systems. {copyright} {ital 1997} {ital The American Physical Society}

  15. A Conjecture on the Origin of Dark Energy

    Institute of Scientific and Technical Information of China (English)

    GAO Shan

    2005-01-01

    @@ A conjecture on the origin of the dark energy in our universe is proposed. The analysis indicates that the dark energy may originate from the quantum fluctuations of space-time limited in our universe.

  16. Conjecturing and Generalization Process on The Structural Development

    Science.gov (United States)

    Ni'mah, Khomsatun; Purwanto; Bambang Irawan, Edy; Hidayanto, Erry

    2017-06-01

    This study aims to describe how conjecturing process and generalization process of structural development to thirty children in middle school at grade 8 in solving problems of patterns. Processing of the data in this study uses qualitative data analysis techniques. The analyzed data is the data obtained through direct observation technique, documentation, and interviews. This study based on research studies Mulligan et al (2012) which resulted in a five - structural development stage, namely prestructural, emergent, partial, structural, and advance. From the analysis of the data in this study found there are two phenomena that is conjecturing and generalization process are related. During the conjecturing process, the childrens appropriately in making hypothesis of patterns problem through two phases, which are numerically and symbolically. Whereas during the generalization of process, the childrens able to related rule of pattern on conjecturing process to another context.

  17. Saari's Conjecture for the Collinear $n$-Body Problem

    CERN Document Server

    Diacu, Florin; Santoprete, Manuele

    2009-01-01

    In 1970 Don Saari conjectured that the only solutions of the Newtonian $n$-body problem that have constant moment of inertia are the relative equilibria. We prove this conjecture in the collinear case for any potential that involves only the mutual distances. Furthermore, in the case of homogeneous potentials, we show that the only collinear and non-zero angular momentum solutions are homographic motions with central configurations.

  18. Gauge-flation and Cosmic No-Hair Conjecture

    CERN Document Server

    Maleknejad, A; Soda, Jiro

    2011-01-01

    Gauge-flation, inflation from non-Abelian gauge fields, was introduced in [1,2]. In this work, we study the cosmic no-hair conjecture in gauge-flation. Starting from Bianchi-type I cosmology and through analytic and numeric studies we demonstrate that the isotropic FLRW inflation is an attractor of the dynamics of the theory and that the anisotropies are damped within a few e-folds, in accord with the cosmic no-hair conjecture.

  19. Upper bounds for prime gaps related to Firoozbakht's conjecture

    OpenAIRE

    Kourbatov, Alexei

    2015-01-01

    We study two kinds of conjectural bounds for the prime gap after the k-th prime $p_k$: (A) $p_{k+1} 9$. The upper bound (A) is equivalent to Firoozbakht's conjecture. We prove that (A) implies (B) with $b=1$; on the other hand, (B) with $b=1.17$ implies (A). We also give other sufficient conditions for (A) that have the form (B) with $b\\to1$ as $p_k\\to\\infty$.

  20. The Generalized Effros-Hahn Conjecture for Groupoids

    CERN Document Server

    Ionescu, Marius

    2008-01-01

    The generalized Effros-Hahn conjecture for groupoid C*-algebras says that, if G is amenable, then every primitive ideal of the groupoid C*-algebra C*(G) is induced from a stability group. We prove that the conjecture is valid for all second countable amenable locally compact Hausdorff groupoids. Our results are a sharpening of previous work of Jean Renault and depend significantly on his results.

  1. Constraints on Dark Energy Models from Weak Gravity Conjecture

    Institute of Scientific and Technical Information of China (English)

    CHEN Xi-Ming; LIU Jie; GONG Yun-Gui

    2008-01-01

    @@ We study the constraints on the dark energy model with constant equation of state parameter w = p/p and the holographic dark energy model by using the weak gravity conjecture. The combination of weak gravity conjecture and the observational data gives w < -0.7 at the 3σ confidence level. The holographic dark energy model realized by a scalar field is in swampland.

  2. The Farrell-Jones Isomorphism Conjecture in K-Theory

    CERN Document Server

    Morteo, Marcelo Gomez

    2012-01-01

    We prove that the Farrell-Jones isomorphism conjecture for non connective K theory for a discrete group G and a coefficient ring R holds true if G belongs to the class of groups acting on trees under certain conditions on G and if R is either regular or hereditary, depending on the structure of G. It is known that these groups verify the isomorphism conjecture if finitely generated for any coefficient ring, but in this article G may not be finitely generated.

  3. A proof of the Barát-Thomassen conjecture

    DEFF Research Database (Denmark)

    Bensmail, Julien; Harutyunyan, Ararat; Le, Tien Nam;

    2017-01-01

    The Barát-Thomassen conjecture asserts that for every tree T on m edges, there exists a constant kT such that every kT-edge-connected graph with size divisible by m can be edge-decomposed into copies of T. So far this conjecture has only been verified when T is a path or when T has diameter at mo...

  4. The Secant Conjecture in the real Schubert calculus

    CERN Document Server

    Garcia-Puente, Luis; Hillar, Christopher J; del Campo, Abraham Martin; Ruffo, James; Sottile, Frank; Teitler, Zach

    2010-01-01

    We formulate the Secant Conjecture, which is a generalization of the Shapiro Conjecture for Grassmannians. It asserts that an intersection of Schubert varieties in a Grassmannian is transverse with all points real, if the flags defining the Schubert varieties are secant along disjoint intervals of a rational normal curve. We present both theoretical evidence for its validity and computational evidence obtained in an experiment using over one terahertz-year of computing, and we discuss some phenomena we observed in our data.

  5. The Normalizer Conjecture in the Alternative Case

    Institute of Scientific and Technical Information of China (English)

    Edgar G. Goodaire; Yuanlin Li

    2001-01-01

    Let L be a torsion loop for which the integral loop ring ZL is an alternative, but not associative, ring. Let Nu(L) denote the normalizer of L in the unit loop u(ZL). We show that Nu(L) = Z(u)L, where Z(u) is the center ofu(ZL), and use this fact to show that u(ZL) has central height 1, unless L is a hamiltonian 2-loop.

  6. Walker circulation in a transient climate

    Science.gov (United States)

    Plesca, Elina; Grützun, Verena; Buehler, Stefan A.

    2016-04-01

    The tropical overturning circulations modulate the heat exchange across the tropics and between the tropics and the poles. The anthropogenic influence on the climate system will affect these circulations, impacting the dynamics of the Earth system. In this work we focus on the Walker circulation. We investigate its temporal and spatial dynamical changes and their link to other climate features, such as surface and sea-surface temperature patterns, El-Niño Southern Oscillation (ENSO), and ocean heat-uptake, both at global and regional scale. In order to determine the impact of anthropogenic climate change on the tropical circulation, we analyze the outputs of 28 general circulation models (GCMs) from the CMIP5 project. We use the experiment with 1% year-1 increase in CO2 concentration from pre-industrial levels to quadrupling of the concentration. Consistent with previous studies (ex. Ma and Xie 2013), we find that for this experiment most GCMs associate a weakening Walker circulation to a warming transient climate. Due to the role of the Walker Pacific cell in the meridional heat and moisture transport across the tropical Pacific and also the connection to ENSO, we find that a weakened Walker circulation correlates with more extreme El-Niño events, although without a change in their frequency. The spatial analysis of the Pacific Walker cell suggests an eastward displacement of the ascending branch, which is consistent with positive SST anomalies over the tropical Pacific and the link of the Pacific Walker cell to ENSO. Recent studies (ex. England et al. 2014) have linked a strengthened Walker circulation to stronger ocean heat uptake, especially in the western Pacific. The inter-model comparison of the correlation between Walker circulation intensity and ocean heat uptake does not convey a robust response for the investigated experiment. However, there is some evidence that a stronger weakening of the Walker circulation is linked to a higher transient climate

  7. Obituary: Robert Mowbray Walker, 1929-2004

    Science.gov (United States)

    Schoenherr, Neil T.

    2004-12-01

    Robert M. Walker, PhD, Professor of Physics in Arts & Sciences and a faculty fellow of the McDonnell Center for the Space Sciences, died of stomach cancer Thursday, 12 February 2004, in Brussels, Belgium. He was 75. Walker worked on the frontiers of space research for more than four decades. Robert Walker was born in Philadelphia on 6 February 1929. His mother was Dorothy Potter and he considered Roger Potter his father though he was not his biological father. His early years were spent in New York City and in upstate New York. He attended the Bronx High School of Science, earned his BS in physics from Union College and in 1954, he received his PhD in particle physics from Yale University. He subsequently joined the General Electric Laboratory in Schenectady, New York where he studied the radiation effects in solids. His work on defects in irradiated copper is still regarded as the definitive work on the topic. In the early 1960s, Walker's discovery of fossil nuclear particle tracks in minerals was instrumental to new developments in geo-chronology and cosmic ray physics. In particular, his discovery of tracks from nuclei heavier than iron opened a new frontier of cosmic ray physics. He subsequently pioneered the use of plastics to detect and count such nuclei in cosmic ray balloon flights. Beginning in 1966, when he moved to Washington University and became the first McDonnell Professor of Physics, his research interests turned more toward space physics. He was the inaugural director of the McDonnell Center, which was established in 1975 by a gift from aerospace pioneer James S. McDonnell. Walker was a member of the NASA committee that allocated samples of the first returned lunar materials, and his laboratory led the way in deciphering their record of lunar, solar system and galactic evolution. Together with Ghislaine Crozaz and other colleagues, Walker made path breaking laboratory studies of the first moon rocks revealing the history of solar radiation and

  8. Blood Facts and Statistics

    Science.gov (United States)

    ... Facts and Statistics Printable Version Blood Facts and Statistics Facts about blood needs Facts about the blood ... to Top Learn About Blood Blood Facts and Statistics Blood Components Whole Blood and Red Blood Cells ...

  9. "Good-Walker" + QCD dipoles = Hard Diffraction

    CERN Document Server

    Peschanski, R

    1998-01-01

    The Good-Walker mechanism for diffraction is shown to provide a link between total and diffractive structure functions and to be relevant for QCD calculations at small x_{Bj}. For Deep-Inelastic scattering on a small-size target (cf. an onium) the r\\^ ole of Good-Walker ``diffractive eigenstates'' is played by the QCD dipoles appearing in the $1/N_C$ limit of QCD. Hard diffraction is thus related to the QCD tripe-dipole vertex which has been recently identified (and calculated) as being a conformal invariant correlator and/or a closed-string amplitude. An extension to hard diffraction at HERA via $k_T-$factorisation of the proton vertices leads to interesting phenomenology.

  10. Auditory perception of a human walker.

    Science.gov (United States)

    Cottrell, David; Campbell, Megan E J

    2014-01-01

    When one hears footsteps in the hall, one is able to instantly recognise it as a person: this is an everyday example of auditory biological motion perception. Despite the familiarity of this experience, research into this phenomenon is in its infancy compared with visual biological motion perception. Here, two experiments explored sensitivity to, and recognition of, auditory stimuli of biological and nonbiological origin. We hypothesised that the cadence of a walker gives rise to a temporal pattern of impact sounds that facilitates the recognition of human motion from auditory stimuli alone. First a series of detection tasks compared sensitivity with three carefully matched impact sounds: footsteps, a ball bouncing, and drumbeats. Unexpectedly, participants were no more sensitive to footsteps than to impact sounds of nonbiological origin. In the second experiment participants made discriminations between pairs of the same stimuli, in a series of recognition tasks in which the temporal pattern of impact sounds was manipulated to be either that of a walker or the pattern more typical of the source event (a ball bouncing or a drumbeat). Under these conditions, there was evidence that both temporal and nontemporal cues were important in recognising theses stimuli. It is proposed that the interval between footsteps, which reflects a walker's cadence, is a cue for the recognition of the sounds of a human walking.

  11. Sharpening the weak gravity conjecture with dimensional reduction

    Science.gov (United States)

    Heidenreich, Ben; Reece, Matthew; Rudelius, Tom

    2016-02-01

    We investigate the behavior of the Weak Gravity Conjecture (WGC) under toroidal compactification and RG flows, finding evidence that WGC bounds for single photons become weaker in the infrared. By contrast, we find that a photon satisfying the WGC will not necessarily satisfy it after toroidal compactification when black holes charged under the Kaluza-Klein photons are considered. Doing so either requires an infinite number of states of different charges to satisfy the WGC in the original theory or a restriction on allowed compactification radii. These subtleties suggest that if the Weak Gravity Conjecture is true, we must seek a stronger form of the conjecture that is robust under compactification. We propose a "Lattice Weak Gravity Conjecture" that meets this requirement: a superextremal particle should exist for every charge in the charge lattice. The perturbative heterotic string satisfies this conjecture. We also use compactification to explore the extent to which the WGC applies to axions. We argue that gravitational instanton solutions in theories of axions coupled to dilaton-like fields are analogous to extremal black holes, motivating a WGC for axions. This is further supported by a match between the instanton action and that of wrapped black branes in a higher-dimensional UV completion.

  12. Prime numbers, quantum field theory and the Goldbach conjecture

    CERN Document Server

    Sanchis-Lozano, Miguel-Angel; Navarro-Salas, Jose

    2012-01-01

    Motivated by the Goldbach and Polignac conjectures in Number Theory, we propose the factorization of a classical non-interacting real scalar field (on a two-cylindrical spacetime) as a product of either two or three (so-called primer) fields whose Fourier expansion exclusively contains prime modes. We undertake the canonical quantization of such primer fields and construct the corresponding Fock space by introducing creation operators $a_p^{\\dag}$ (labeled by prime numbers $p$) acting on the vacuum. The analysis of our model, based on the standard rules of quantum field theory, suggests intriguing connections between different topics in Number Theory, notably the Riemann hypothesis and the Goldbach and Polignac conjectures. Our analysis also suggests that the (non) renormalizability properties of the proposed model could be linked to the possible validity or breakdown of the Goldbach conjecture for large integer numbers.

  13. The mixed Schmidt conjecture in the theory of Diophantine approximation

    CERN Document Server

    Badziahin, Dzmitry; Velani, Sanju

    2010-01-01

    Let $\\mathcal{D}=(d_n)_{n=1}^\\infty$ be a bounded sequence of integers with $d_n\\ge 2$ and let $(i, j)$ be a pair of strictly positive numbers with $i+j=1$. We prove that the set of $x \\in \\RR$ for which there exists some constant $c(x) > 0$ such that \\[ \\max\\{|q|_\\DDD^{1/i}, \\|qx\\|^{1/j}\\} > c(x)/ q \\qquad \\forall q \\in \\NN \\] is one quarter winning (in the sense of Schmidt games). Thus the intersection of any countable number of such sets is of full dimension. In turn, this establishes the natural analogue of Schmidt's conjecture within the framework of the de Mathan-Teuli\\'e conjecture -- also known as the `Mixed Littlewood Conjecture'.

  14. Can we observationally test the weak cosmic censorship conjecture?

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Lingyao; Malafarina, Daniele; Bambi, Cosimo [Fudan University, Department of Physics, Center for Field Theory and Particle Physics, Shanghai (China)

    2014-08-15

    In general relativity, gravitational collapse of matter fields ends with the formation of a spacetime singularity, where the matter density becomes infinite and standard physics breaks down. According to the weak cosmic censorship conjecture, singularities produced in the gravitational collapse cannot be seen by distant observers and must be hidden within black holes. The validity of this conjecture is still controversial and at present we cannot exclude that naked singularities can be created in our Universe from regular initial data. In this paper, we study the radiation emitted by a collapsing cloud of dust and check whether it is possible to distinguish the birth of a black hole from the one of a naked singularity. In our simple dust model, we find that the properties of the radiation emitted in the two scenarios is qualitatively similar. That suggests that observational tests of the cosmic censorship conjecture may be very difficult, even in principle. (orig.)

  15. A proof of Connelly's conjecture on 3-connected generic cycles

    DEFF Research Database (Denmark)

    Berg, Alex Rune; Jordán, Tibor

    2001-01-01

    A graph G = (V , E) is called a generic circuit if |E| = 2|V| - 2 and every X ⊂ V with 2 ≥ |X| ≥ |V| - 1 satisfies i(X) ≤ 2|X| - 3. Here i(X) denotes the number of edges induced by X. The operation extension subdivides an edge uw of a graph by a new vertex v and adds a new edge vz for some vertex z...... ≠ u, w. Connelly conjectured that every 3-connected generic circuit can be obtained from K4 by a sequence of extensions. We prove this conjecture. As a corollary, we also obtain a special case of a conjecture of Hendrickson on generically globally rigid graphs....

  16. The Andr\\'e-Oort Conjecture for Drinfeld Modular Varieties

    CERN Document Server

    Hubschmid, Patrik

    2012-01-01

    We consider the analogue of the Andr\\'e-Oort conjecture for Drinfeld modular varieties which was formulated by Breuer. We prove this analogue for special points with separable reflex field over the base field by adapting methods which were used by Klingler and Yafaev to prove the Andr\\'e-Oort conjecture under the generalized Riemann hypothesis in the classical case. Our result extends results of Breuer showing the correctness of the analogue for special points lying in a curve and for special points having a certain behaviour at a fixed set of primes.

  17. Saari's Homographic Conjecture of the Three-Body Problem

    CERN Document Server

    Diacu, Florin; Perez-Chavela, Ernesto; Santoprete, Manuele

    2009-01-01

    Saari's homographic conjecture, which extends a classical statement proposed by Donald Saari in 1970, claims that solutions of the Newtonian $n$-body problem with constant configurational measure are homographic. In other words, if the mutual distances satisfy a certain relationship, the configuration of the particle system may change size and position but not shape. We prove this conjecture for large sets of initial conditions in three-body problems given by homogeneous potentials, including the Newtonian one. Some of our results are true for $n\\ge 3$.

  18. Cosmic Censorship Conjecture in Kerr-Sen Black Hole

    CERN Document Server

    Gwak, Bogeun

    2016-01-01

    The validity of cosmic censorship conjecture for the Kerr-Sen black hole, which is a solution to the low-energy effective field theory for four-dimensional heterotic string theory, is investigated using charged particle absorption. When the black hole absorbs the particle, its charges are changed due to the conserved quantities of the particle. Changes in the black hole are constrained to the equation for the motion of the particle and are consistent with the laws of thermodynamics. Particle absorption increases the mass of the extremal Kerr-Sen black hole to more than its charges, so the black hole cannot be overcharged. Therefore, cosmic censorship conjecture is valid.

  19. An analytical proof for Lehmer's totient conjecture using Mertens' theorems

    OpenAIRE

    2016-01-01

    We make an analytical proof for Lehmer's totient conjecture. Lehmer conjectured that there is no solution for the congruence equation $n-1\\equiv 0~(mod~\\phi(n))$ with composite integers,$n$, where $\\phi(n)$ denotes Euler's totient function. He also showed that if the equation has any composite solutions, $n$ must be odd, square-free, and divisible by at least 7 primes. Several people have obtained conditions on values ,$n$, and number of square-free primes constructing $n$ if the equation can...

  20. An analytical proof for Lehmer's totient conjecture using Mertens' theorems

    OpenAIRE

    Sabihi, Ahmad

    2016-01-01

    We make an analytical proof for Lehmer's totient conjecture. Lehmer conjectured that there is no solution for the congruence equation $n-1\\equiv 0~(mod~\\phi(n))$ with composite integers,$n$, where $\\phi(n)$ denotes Euler's totient function. He also showed that if the equation has any composite solutions, $n$ must be odd, square-free, and divisible by at least 7 primes. Several people have obtained conditions on values ,$n$, and number of square-free primes constructing $n$ if the equation can...

  1. The Dirac Conjecture and the Non-uniqueness of Lagrangian

    CERN Document Server

    Wang, Yong-Long; Jiang, Hua; Lu, Wei-Tao; Pan, Hong-Zhe

    2013-01-01

    We prove the validity of the Dirac conjecture generally by adding the total time derivatives of all constraints to the Lagrangian step by step. It is worthy to state that the total time derivatives added to the original Lagrangian can turn up some constraints, and discover the symmetries hidden in the original Lagrangian. For a constrained system, the extended Hamiltonian $H_E$ contains more constraints, and shows more symmetries. We discuss the Cawley's counterexample, and prove it not a real one to the Dirac conjecture. And we offer an example, its extended Hamiltonian is better that its total Hamiltonian for its Lagrangian.

  2. On the relation of Matrix theory and Maldacena conjecture

    OpenAIRE

    Silva, Pedro J.

    1998-01-01

    We report a sign that M(atrix) theory conjecture and the Maldacena conjecture for the case of D0-branes are compatible. Furthermore Maldacena point of view implies a restriction of range of validity in the DLCQ version of M(atrix) theory. The analysis is based on the uplift of type IIA supersymetric solution in the Maldacena approach to eleven dimensions, using a boost as a main tool. The relation is explored on both, IMF and DLCF versions of M(atrix) theory

  3. State Health Facts

    Science.gov (United States)

    ... Facts Home State Health Facts Search State Health Facts: Choose Category - or - Choose Location Demographics and the ... Expansion Enrollment Featured State Data Resources Medicaid State Fact Sheets What percentage of people are covered by ...

  4. Chaotic Friedmann-Robertson-Walker Cosmology

    CERN Document Server

    Calzetta, E A

    1993-01-01

    We show that the dynamics of a spatially closed Friedmann - Robertson - Walker Universe conformally coupled to a real, free, massive scalar field, is chaotic, for large enough field amplitudes. We do so by proving that this system is integrable under the adiabatic approximation, but that the corresponding KAM tori break up when non adiabatic terms are considered. This finding is confirmed by numerical evaluation of the Lyapunov exponents associated with the system, among other criteria. Chaos sets strong limitations to our ability to predict the value of the field at the Big Crunch, from its given value at the Big Bang. (Figures available on request)

  5. William Walker en Centroamérica

    OpenAIRE

    Medaglia Gómez, Marco Aurelio

    2007-01-01

    La campaña Nacional (1856-1857) tuvo su origen en la presencia de los filibusteros en Nicaragua. William Walker fue el mayor representante de la política del “Destino Manifiesto” de los Estados Unidos a mediados del siglo XIX. Esto se manifiesta en sus incursiones en Baja California y Sonora y más tarde en Nicaragua y sus pretensiones sobre Centroamérica. La llamada “falange americana” encarna los intereses de los estados sureños que pretendían mantener su modelo económico basado en la esclav...

  6. FACT. New image parameters based on the watershed-algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Linhoff, Lena; Bruegge, Kai Arno; Buss, Jens [TU Dortmund (Germany). Experimentelle Physik 5b; Collaboration: FACT-Collaboration

    2016-07-01

    FACT, the First G-APD Cherenkov Telescope, is the first imaging atmospheric Cherenkov telescope that is using Geiger-mode avalanche photodiodes (G-APDs) as photo sensors. The raw data produced by this telescope are processed in an analysis chain, which leads to a classification of the primary particle that induce a shower and to an estimation of its energy. One important step in this analysis chain is the parameter extraction from shower images. By the application of a watershed algorithm to the camera image, new parameters are computed. Perceiving the brightness of a pixel as height, a set of pixels can be seen as 'landscape' with hills and valleys. A watershed algorithm groups all pixels to a cluster that belongs to the same hill. From the emerging segmented image, one can find new parameters for later analysis steps, e.g. number of clusters, their shape and containing photon charge. For FACT data, the FellWalker algorithm was chosen from the class of watershed algorithms, because it was designed to work on discrete distributions, in this case the pixels of a camera image. The FellWalker algorithm is implemented in FACT-tools, which provides the low level analysis framework for FACT. This talk will focus on the computation of new, FellWalker based, image parameters, which can be used for the gamma-hadron separation. Additionally, their distributions concerning real and Monte Carlo Data are compared.

  7. The prime-pair conjectures of Hardy and Littlewood

    NARCIS (Netherlands)

    Korevaar, J.

    2012-01-01

    By (extended) Wiener-Ikehara theory, the prime-pair conjectures are equivalent to simple pole-type boundary behavior of corresponding Dirichlet series. Under a weak Riemann-type hypothesis, the boundary behavior of weighted sums of the Dirichlet series can be expressed in terms of the behavior of ce

  8. The remodeling conjecture and the Faber-Pandharipande formula

    CERN Document Server

    Bouchard, Vincent; Marchal, Olivier; Sulkowski, Piotr

    2011-01-01

    In this note, we prove that the free energies F_g constructed from the Eynard-Orantin topological recursion applied to the curve mirror to C^3 reproduce the Faber-Pandharipande formula for genus g Gromov-Witten invariants of C^3. This completes the proof of the remodeling conjecture for C^3.

  9. Local Conjecturing Process in the Solving of Pattern Generalization Problem

    Science.gov (United States)

    Sutarto; Nusantara, Toto; Subanji; Sisworo

    2016-01-01

    This aim of this study is to describe the process of local conjecturing in generalizing patterns based on Action, Process, Object, Schema (APOS) theory. The subjects were 16 grade 8 students from a junior high school. Data collection used Pattern Generalization Problem (PGP) and interviews. In the first stage, students completed PGP; in the second…

  10. A new proof of Faber's intersection number conjecture

    CERN Document Server

    Buryak, A

    2009-01-01

    We give a new proof of Faber's intersection number conjecture concerning the top intersections in the tautological ring of the moduli space of curves $\\M_g$. The proof is based on a very straightforward geometric and combinatorial computation with double ramification cycles.

  11. Comments on the floating body and the hyperplane conjecture

    CERN Document Server

    Fresen, Daniel

    2011-01-01

    We provide upper and lower bounds on the logarithmic Hausdorff distance between an arbitrary convex body $K\\subset \\mathbb{R}^{d}$\\ and the convex floating body $K_{\\delta}$ inside $K$. We also discuss the hyperplane conjecture (the slicing problem) and provide a reformulation of this famous unsolved mystery in terms of the floating body.

  12. Is the five-flow conjecture almost false?

    CERN Document Server

    Jacobsen, Jesper L

    2010-01-01

    The number of nowhere-zero Z_Q flows on a bridgeless graph G can be shown to be a polynomial in Q, defining the flow polynomial \\Phi_G(Q). According to Tutte's five-flow conjecture, \\Phi_G(5) > 0 for any G. A conjecture by Welsh that \\Phi_G(Q) has no real roots for Q \\in (4,\\infty) was recently disproved by Haggard, Pearce and Royle. These authors conjectured the same result for Q \\in [5,\\infty). We study the real and complex roots of \\Phi_G(Q) for a family of non-planar cubic graphs known as generalised Petersen graphs G(n,k). We show that the modified conjecture on real flow roots is also false, by exhibiting infinitely many real flow roots Q>5 within the class G(nk,k). In particular, we compute explicitly G(119,7) showing that it has real roots at Q\\approx 5.0000197675 and Q\\approx 5.1653424423. We moreover prove that the graph families G(6n,6) and G(7n,7) possess real flow roots that accumulate at Q=5 as n\\to\\infty; and that Q_c(7)\\approx 5.2352605291 is a non-isolated accumulation point of real zeros of ...

  13. Game Show Mathematics: Specializing, Conjecturing, Generalizing, and Convincing

    Science.gov (United States)

    Lane, Catherine Pullin; Harkness, Shelly Sheats

    2012-01-01

    This article describes the authors' use of three game shows--"Survivor," "The Biggest Loser," and "Deal or No Deal?"--to determine to what degree students engaged in mathematical thinking: specializing, conjecturing, generalizing, and convincing (Burton, 1984). Student responses to the task of creating winning strategies to these shows were…

  14. Counterexample to a Penrose inequality conjectured by Gibbons

    CERN Document Server

    Dain, Sergio; Yamada, Sumio

    2010-01-01

    We show that the Brill-Lindquist initial data provides a counterexample to a Riemannian Penrose inequality with charge conjectured by G. Gibbons. The observation illustrates a sub-additive characteristic of the area radii for the individual connected components of an outermost horizon as a lower bound of the ADM mass.

  15. On the general elephant conjecture for Mori conic bundles

    CERN Document Server

    Prokhorov, Yu G

    1996-01-01

    Let $f:X\\to S$ be an extremal contraction from a threefolds with terminal singularities onto a surface (so called Mori conic bundle). We study some particular cases of such contractions: quotients of usual conic bundles and index two contractions. Assuming Reid's general elephants conjecture we also obtain a rough classification. We present many examples.

  16. Min-Rank Conjecture for Log-Depth Circuits

    CERN Document Server

    Jukna, S

    2010-01-01

    A completion of an m-by-n matrix A with entries in {0,1,*} is obtained by setting all *-entries to constants 0 or 1. A system of semi-linear equations over GF(2) has the form Mx=f(x), where M is a completion of A and f:{0,1}^n --> {0,1}^m is an operator, the i-th coordinate of which can only depend on variables corresponding to *-entries in the i-th row of A. We conjecture that no such system can have more than 2^{n-c\\cdot mr(A)} solutions, where c>0 is an absolute constant and mr(A) is the smallest rank over GF(2) of a completion of A. The conjecture is related to an old problem of proving super-linear lower bounds on the size of log-depth boolean circuits computing linear operators x --> Mx. The conjecture is also a generalization of a classical question about how much larger can non-linear codes be than linear ones. We prove some special cases of the conjecture and establish some structural properties of solution sets.

  17. Hamiltonian formulation of the Belinskii-Khalatnikov-Lifshitz conjecture

    NARCIS (Netherlands)

    Ashtekar, A.; Henderson, A.; Sloan, D.J.A.

    2011-01-01

    The Belinskii, Khalatnikov, and Lifshitz conjecture [ V. A. Belinskii, I. M. Khalatnikov and E. M. Lifshitz Adv. Phys. 19 525 (1970)] posits that on approach to a spacelike singularity in general relativity the dynamics are well approximated by “ignoring spatial derivatives in favor of time

  18. The stable moduli space of Riemann surfaces: Mumford's conjecture

    DEFF Research Database (Denmark)

    Madsen, I.; Weiss, Michael

    2007-01-01

    D. Mumford conjectured in "Towards an enumerative geometry of the moduli space of curves" that the rational cohomology of the stable moduli space of Riemann surfaces is a polynomial algebra generated by certain classes $\\kappa_i$ of dimension $2i$. For the purpose of calculating rational cohomolo...

  19. The Bloch-Kato Conjecture and Galois Theory

    CERN Document Server

    Karagueuzian, Dikran; Miná\\vc, Ján

    2010-01-01

    We investigate the relations in Galois groups of maximal p-extensions of fields, the structure of their natural filtrations, and their relationship with the Bloch-Kato conjecture proved by Rost and Voevodsky with Weibel's patch. Our main focus is on the third degree, but we provide examples for all degrees.

  20. Symmetric moment problems and a conjecture of Valent

    Science.gov (United States)

    Berg, C.; Szwarc, R.

    2017-03-01

    In 1998 Valent made conjectures about the order and type of certain indeterminate Stieltjes moment problems associated with birth and death processes which have polynomial birth and death rates of degree {p≥slant 3}. Romanov recently proved that the order is 1/p as conjectured. We prove that the type with respect to the order is related to certain multi-zeta values and that this type belongs to the interval which also contains the conjectured value. This proves that the conjecture about type is asymptotically correct as p\\to∞. The main idea is to obtain estimates for order and type of symmetric indeterminate Hamburger moment problems when the orthonormal polynomials P_n and those of the second kind Q_n satisfy P2n^2(0)∼ c_1n-1/β and Q2n-1^2(0)∼ c2 n-1/α, where 0proof of Romanov's Theorem that the order is 1/p. Bibliography: 19 titles.

  1. Topological Hochschild homology and the Bass trace conjecture

    DEFF Research Database (Denmark)

    Berrick, A. J.; Hesselholt, Lars

    2015-01-01

    We use the methods of topological Hochschild homology to shed new light on groups satisfying the Bass trace conjecture. Factorization of the Hattori–Stallings rank map through the Bökstedt–Hsiang–Madsen cyclotomic trace map leads to Linnell's restriction on such groups. As a new consequence...

  2. On the General Erdős-Turán Conjecture

    Directory of Open Access Journals (Sweden)

    Georges Grekos

    2014-01-01

    Full Text Available The general Erdős-Turán conjecture states that if A is an infinite, strictly increasing sequence of natural numbers whose general term satisfies an≤cn2, for some constant c>0 and for all n, then the number of representations functions of A is unbounded. Here, we introduce the function ψ(n, giving the minimum of the maximal number of representations of a finite sequence A={ak:1≤k≤n} of n natural numbers satisfying ak≤k2 for all k. We show that ψ(n is an increasing function of n and that the general Erdős-Turán conjecture is equivalent to limn→∞ψ(n=∞. We also compute some values of ψ(n. We further introduce and study the notion of capacity, which is related to the ψ function by the fact that limn→∞ψ(n is the capacity of the set of squares of positive integers, but which is also of intrinsic interest.

  3. Variante de Dandy Walker: relato de caso = Dandy Walker variant: a case report

    Directory of Open Access Journals (Sweden)

    Khan, Richard Lester et al.

    2009-01-01

    Full Text Available Objetivos: relatar o caso de um paciente com variante de Dandy Walker, chamando atenção para a importância da suspeita, investigação e manejo das repercussões clínicas. Descrição do caso: é relatado o caso de um paciente do sexo masculino, com quadro clínico e radiológico típico da Variante de Dandy Walker. Durante o pré-natal, através de ecografia obstétrica com 23 semanas e 3 dias, apresentou alterações sugestivas de Síndrome de Dandy Walker. Ao nascimento apresentou exame físico com fenda palatina, criptorquidia à direita, hexodactilia em ambos os pés. Apresentava ainda ecocardiograma com forame oval patente e persistência do canal arterial. O diagnóstico foi estabelecido através da ressonância magnética realizada após o nascimento, que evidenciava hipoplasia do vermis cerebelar, alargamento da fossa posterior e leve dilatação ventricular. Conclusões: este artigo procura caracterizar a variante de Dandy Walker, que é uma malformação congênita do sistema nervoso central e é o tipo mais comum da Síndrome de Dandy Walker. Seu fenótipo é variável, devendo-se sempre pesquisar malformações tanto intra quanto extracranianas, visto que o risco de mortalidade pós-natal aumenta quando existe esta associação. O tratamento envolve equipe multidisciplinar e o prognóstico é reservado, variando conforme o fenótipo.

  4. Superdiffusive transport by multivalent molecular walkers moving under load

    CERN Document Server

    Olah, Mark J

    2012-01-01

    We introduce a model for translational molecular motors to demonstrate that a multivalent catalytic walker with flexible, uncoordinated legs can transform the free energy of surface-bound substrate sites into mechanical work and undergo biased, superdiffusive motion, even in opposition to an external load force. The walker in the model lacks any inherent orientation of body or track, and its legs have no chemomechanical coupling other than the passive constraint imposed by their connection to a common body. Yet, under appropriate kinetic conditions the walker's motion is biased in the direction of unvisited sites, which allows the walker to move nearly ballistically away from the origin as long as a local supply of unmodified substrate sites is available. The multivalent random walker model is mathematically formulated as a continuous-time Markov process and is studied numerically. We use Monte Carlo simulations to generate ensemble estimates of the mean squared displacement and mean work done for this non-er...

  5. Structural Biology Fact Sheet

    Science.gov (United States)

    ... Home > Science Education > Structural Biology Fact Sheet Structural Biology Fact Sheet Tagline (Optional) Middle/Main Content Area ​Other Fact Sheets What is structural biology? Structural biology is the study of how biological ...

  6. Facts about Cataract

    Science.gov (United States)

    ... Home > Eye Health Information > Cataract > Facts About Cataract Facts About Cataract This information was developed by the ... citizen to get this type of cataract. In fact, people can have an age-related cataract in ...

  7. Facts About Pink Eye

    Science.gov (United States)

    ... Information > Pink Eye (Conjunctivitis) > Facts About Pink Eye Facts About Pink Eye Pink eye is one of ... for preventing eye infections. Last Reviewed: November 2015 Fact Sheet Blurb The National Eye Institute (NEI) is ...

  8. Facts about Folic Acid

    Science.gov (United States)

    ... Partners About Us Information For… Media Policy Makers Facts About Folic Acid Language: English (US) Español ( ... a woman needs 400 micrograms (mcg) every day. Facts About Folic Acid Download and print this fact ...

  9. A note on a conjecture of Graffiti%关于Graffiti的一个猜想

    Institute of Scientific and Technical Information of China (English)

    陈恬; 束金龙

    2006-01-01

    In this paper,we will give a very simpleproof of a conjecture of Graffiti. (WOW Conjecture 584) :Let T be a tree of order n with independence number α , thenλ1 ≤ 2 + α , where λ1 is the Laplacian speetralradius. ( Xiao -dong Zhang , On the two conjectures of Graffiti, Linear Algebra and its Applications , described all extremal treesthat attain the maximal Laplacian spectral radius and used theresults to show conjectures.

  10. Class numbers of cyclic 2-extensions and Gross conjecture over Q

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The Gross conjecture over Q was first claimed by Aoki in 1991.However,the original proof contains too many mistakes and false claims to be considered as a serious proof.This paper is an attempt to find a sound proof of the Gross conjecture under the outline of Aoki.We reduce the conjecture to an elementary conjecture concerning the class numbers of cyclic 2-extensions of Q.

  11. The mixed Ax-Lindemann theorem and its applications to the Zilber-Pink conjecture

    NARCIS (Netherlands)

    Gao, Ziyang

    2014-01-01

    The Zilber-Pink conjecture is a common generalization of the Andre-Oort and the Mordell-Lang conjectures. In this dissertation, we study its sub-conjectures: Andre-Oort, which predicts that a subvariety of a mixed Shimura variety having dense intersection with the set of special points is special; a

  12. Equivalence of ELSV and Bouchard-Mariño conjectures for r-spin Hurwitz numbers

    NARCIS (Netherlands)

    Shadrin, S.; Spitz, L.; Zvonkine, D.

    2015-01-01

    We propose two conjectures on Hurwitz numbers with completed (r+1)-cycles, or, equivalently, on certain relative Gromov-Witten invariants of the projective line. The conjectures are analogs of the ELSV formula and of the Bouchard-Mariño conjecture for ordinary Hurwitz numbers. Our r-ELSV formula is

  13. A Proof of the Boyd-Carr Conjecture

    CERN Document Server

    Schalekamp, Frans; van Zuylen, Anke

    2011-01-01

    Determining the precise integrality gap for the subtour LP relaxation of the traveling salesman problem is a significant open question, with little progress made in thirty years in the general case of symmetric costs that obey triangle inequality. Boyd and Carr [3] observe that we do not even know the worst-case upper bound on the ratio of the optimal 2-matching to the subtour LP; they conjecture the ratio is at most 10/9. In this paper, we prove the Boyd-Carr conjecture. In the case that a fractional 2-matching has no cut edge, we can further prove that an optimal 2-matching is at most 10/9 times the cost of the fractional 2-matching.

  14. Prime Numbers, Quantum Field Theory and the Goldbach Conjecture

    Science.gov (United States)

    Sanchis-Lozano, Miguel-Angel; Barbero G., J. Fernando; Navarro-Salas, José

    2012-09-01

    Motivated by the Goldbach conjecture in number theory and the Abelian bosonization mechanism on a cylindrical two-dimensional space-time, we study the reconstruction of a real scalar field as a product of two real fermion (so-called prime) fields whose Fourier expansion exclusively contains prime modes. We undertake the canonical quantization of such prime fields and construct the corresponding Fock space by introducing creation operators bp\\dag — labeled by prime numbers p — acting on the vacuum. The analysis of our model, based on the standard rules of quantum field theory and the assumption of the Riemann hypothesis, allows us to prove that the theory is not renormalizable. We also comment on the potential consequences of this result concerning the validity or breakdown of the Goldbach conjecture for large integer numbers.

  15. Complex analysis conformal inequalities and the Bieberbach conjecture

    CERN Document Server

    Kythe, Prem K

    2015-01-01

    Complex Analysis: Conformal Inequalities and the Bieberbach Conjecture discusses the mathematical analysis created around the Bieberbach conjecture, which is responsible for the development of many beautiful aspects of complex analysis, especially in the geometric-function theory of univalent functions. Assuming basic knowledge of complex analysis and differential equations, the book is suitable for graduate students engaged in analytical research on the topics and researchers working on related areas of complex analysis in one or more complex variables. The author first reviews the theory of analytic functions, univalent functions, and conformal mapping before covering various theorems related to the area principle and discussing Löwner theory. He then presents Schiffer’s variation method, the bounds for the fourth and higher-order coefficients, various subclasses of univalent functions, generalized convexity and the class of a-convex functions, and numerical estimates of the coefficient problem. The boo...

  16. Constraints on axion inflation from the weak gravity conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Rudelius, Tom [Jefferson Physical Laboratory, Harvard University,Cambridge, MA 02138 (United States)

    2015-09-08

    We derive constraints facing models of axion inflation based on decay constant alignment from a string-theoretic and quantum gravitational perspective. In particular, we investigate the prospects for alignment and ‘anti-alignment’ of C{sub 4} axion decay constants in type IIB string theory, deriving a strict no-go result in the latter case. We discuss the relationship of axion decay constants to the weak gravity conjecture and demonstrate agreement between our string-theoretic constraints and those coming from the ‘generalized’ weak gravity conjecture. Finally, we consider a particular model of decay constant alignment in which the potential of C{sub 4} axions in type IIB compactifications on a Calabi-Yau three-fold is dominated by contributions from D7-branes, pointing out that this model evades some of the challenges derived earlier in our paper but is highly constrained by other geometric considerations.

  17. Complete solution to a conjecture of Zhang-Liu-Zhou

    Directory of Open Access Journals (Sweden)

    Mostafa Tavakoli

    2014-11-01

    Full Text Available Let dn;m = 2n+1 and En;m be the graph obtained from a path Pdn;m+1 = v0v1:::vdn;m by joining each vertex of Kn by joining each vertex of Kn. Zhang, Liu and Zhou [On the maximal eccentric connectivity indices of graphs, Appl. Math. J. Chinese Univ., in press] conjectured that if dn;m > 3, then En;m is the graph with maximal eccentric connectivity ndex among all connected graph with n vertices and m edges. In this note, we prove this conjecture. Moreover, we present the graph with maximal eccentric connectivity index among the connected graphs with n vertices. Finally, the minimum of this graph invariant n the classes of tricyclic and tetracyclic graphs are computed.

  18. Introduction to sofic and hyperlinear groups and Connes' embedding conjecture

    CERN Document Server

    Capraro, Valerio

    2015-01-01

    This monograph presents some cornerstone results in the study of sofic and hyperlinear groups and the closely related Connes' embedding conjecture. These notions, as well as the proofs of many results, are presented in the framework of model theory for metric structures. This point of view, rarely explicitly adopted in the literature, clarifies the ideas therein, and provides additional tools to attack open problems. Sofic and hyperlinear groups are countable discrete groups that can be suitably approximated by finite symmetric groups and groups of unitary matrices. These deep and fruitful notions, introduced by Gromov and Radulescu, respectively, in the late 1990s, stimulated an impressive amount of research in the last 15 years, touching several seemingly distant areas of mathematics including geometric group theory, operator algebras, dynamical systems, graph theory, and quantum information theory. Several long-standing conjectures, still open for arbitrary groups, are now settled for sofic or hyperlinear ...

  19. The Baum-Connes conjecture for free orthogonal quantum groups

    CERN Document Server

    Voigt, Christian

    2009-01-01

    We prove an analogue of the Baum-Connes conjecture for free orthogonal quantum groups. More precisely, we show that these quantum groups have a $ \\gamma $-element and that $ \\gamma = 1 $. It follows that free orthogonal quantum groups are $ K $-amenable. We compute explicitly their $ K $-theory and deduce in the unimodular case that the corresponding reduced $ C^* $-algebras do not contain nontrivial idempotents. Our approach is based on the reformulation of the Baum-Connes conjecture by Meyer and Nest using the language of triangulated categories. An important ingredient is the theory of monoidal equivalence of compact quantum groups developed by Bichon, De Rijdt and Vaes. This allows us to study the problem in terms of the quantum group $ SU_q(2) $. The crucial part of the argument is a detailed analysis of the equivariant Kasparov theory of the standard Podle\\'s sphere.

  20. Virus Structure: From Crick and Watson to a New Conjecture

    CERN Document Server

    Iorio, Alfredo

    2007-01-01

    We conjecture that certain patterns (scars), theoretically and numerically predicted to be formed by electrons arranged on a sphere to minimize the repulsive Coulomb potential (the Thomson problem) and experimentally found in spherical crystals formed by self-assembled polystyrene beads (an instance of the generalized Thomson problem), could be relevant to extend the classic Caspar and Klug construction for icosahedrally-shaped virus capsids. The main idea is that scars could be produced at an intermediate stage of the assembly of the virus capsids and the release of the bending energy present in scars into stretching energy could allow for a variety of non-spherical capsids' shapes. The conjecture can be tested in experiments on the assembly of artificial protein-cages where these scars should appear.

  1. The escape problem for mortal walkers

    CERN Document Server

    Grebenkov, D S

    2016-01-01

    We introduce and investigate the escape problem for random walkers that may eventually die, decay, bleach, or lose activity during their diffusion towards an escape or reactive region on the boundary of a confining domain. In the case of a first-order kinetics (i.e., exponentially distributed lifetimes), we study the effect of the associated death rate onto the survival probability, the exit probability, and the mean first passage time. We derive the upper and lower bounds and some approximations for these quantities. We reveal three asymptotic regimes of small, intermediate and large death rates. General estimates and asymptotics are compared to several explicit solutions for simple domains, and to numerical simulations. These results allow one to account for stochastic photobleaching of fluorescent tracers in bio-imaging, degradation of mRNA molecules in genetic translation mechanisms, or high mortality rates of spermatozoa in the fertilization process. This is also a mathematical ground for optimizing stor...

  2. Proof of the WARM whisker conjecture for neuronal connections

    Science.gov (United States)

    Holmes, Mark; Kleptsyn, Victor

    2017-04-01

    This paper is devoted to the study of the so-called WARM reinforcement models that are generalisations of Pólya's urn. We show that in the graph setting, once the exponent α of the reinforcement function is greater than 2, the stable and critical equilibria can be supported only on spanning forests, and once α > 25 , on spanning whisker forests. Thus, we prove the whisker forests conjecture from Hofstad et al. [Ann. Appl. Probab. 26(4), 2494-2539 (2016)].

  3. On Howard's Conjecture in Heterogeneous Shear Flow Problem

    Indian Academy of Sciences (India)

    R G Shandil; Jagjit Singh

    2003-11-01

    Howard's conjecture, which states that in the linear instability problem of inviscid heterogeneous parallel shear flow growth rate of an arbitrary unstable wave must approach zero as the wave length decreases to zero, is established in a mathematically rigorous fashion for plane parallel heterogeneous shear flows with negligible buoyancy force $g \\ll 1$ (Miles J W, J. Fluid Mech. 10 (1961) 496–508), where is the basic heterogeneity distribution function).

  4. On a supercongruence conjecture of Rodriguez-Villegas

    CERN Document Server

    McCarthy, Dermot

    2012-01-01

    In examining the relationship between the number of points over $\\mathbb{F}_p$ on certain Calabi-Yau manifolds and hypergeometric series which correspond to a particular period of the manifold, Rodriguez-Villegas identified numerically 22 possible supercongruences. We prove one of the outstanding supercongruence conjectures between a special value of a truncated generalized hypergeometric series and the $p$-th Fourier coefficient of a modular form.

  5. On the first integral conjecture of Rene Thom

    OpenAIRE

    Cresson, Jacky; Daniilidis, Aris; Shiota, Masahiro

    2007-01-01

    More that half a century ago R. Thom asserted in an unpublished manuscript that, generically, vector fields on compact connected smooth manifolds without boundary can admit only trivial continuous first integrals. Though somehow unprecise for what concerns the interpretation of the word \\textquotedblleft generically\\textquotedblright, this statement is ostensibly true and is nowadays commonly accepted. On the other hand, the (few) known formal proofs of Thom's conjecture are all relying to th...

  6. Melham's Conjecture on Odd Power Sums of Fibonacci Numbers

    OpenAIRE

    Sun, Brian Y.; Xie, Matthew H. Y.; Yang, Arthur L.B.

    2015-01-01

    Ozeki and Prodinger showed that the odd power sum of the first several consecutive Fibonacci numbers of even order is equal to a polynomial evaluated at certain Fibonacci number of odd order. We prove that this polynomial and its derivative both vanish at $1$, and will be an integer polynomial after multiplying it by a product of the first consecutive Lucas numbers of odd order. This presents an affirmative answer to a conjecture of Melham.

  7. Regarding a Representation-Theoretic Conjecture of Wigderson

    CERN Document Server

    Moore, Cristopher

    2010-01-01

    We show that there exists a family of irreducible representations R_i (of finite groups G_i) such that, for any constant t, the average of R_i over t uniformly random elements g_1, ..., g_t of G_i has operator norm 1 with probability approaching 1 as i limits to infinity. This settles a conjecture of Wigderson in the negative.

  8. A groupoid approach to L\\"uck's amenability conjecture

    CERN Document Server

    Kyed, David

    2012-01-01

    We prove that amenability of a discrete group is equivalent to dimension flatness of certain ring inclusions naturally associated with measure preserving actions of the group. This provides a group-measure space theoretic solution to a conjecture of L\\"uck stating that amenability of a group is characterized by dimension flatness of the inclusion of its complex group algebra into the associated von Neumann algebra.

  9. Factorization Conjecture and the Open/Closed String Correspondence

    CERN Document Server

    Baumgartl, M; Shatashvili, S L; Baumgartl, Marcus; Sachs, Ivo; Shatashvili, Samson L.

    2005-01-01

    We present evidence for the factorization of the world-sheet path integrals for 2d conformal field theories on the disk into bulk and boundary contributions. This factorization is then used to reinterpret a shift in closed string backgrounds in terms of boundary deformations in background independent open string field theory. We give a proof of the factorization conjecture in the cases where the background is represented by WZW and related models.

  10. Compact Lie groups: Euler constructions and generalized Dyson conjecture

    CERN Document Server

    Cacciatori, S L; Scotti, A

    2012-01-01

    In this paper we present a very general method to construct generalized Euler parameterizations for compact simple Lie groups w.r.t. maximally symmetrically embedded simple Lie groups. Our construction is based on a detailed analysis of the geometry of these groups, which moreover gives rise to an interesting connection with certain generalized Dyson integrals. In particular, we obtain a geometry based proof of the generalized Macdonald conjecture correspondent to the root systems associated to all irreducible symmetric spaces.

  11. On Lehmer's Conjecture for Polynomials and for Elliptic Curves

    CERN Document Server

    Silverman, Joseph H

    2010-01-01

    A number of authors have proven explicit versions of Lehmer's conjecture for polynomials whose coefficients are all congruent to 1 modulo m. We prove a similar result for polynomials f(X) that are divisible in (Z/mZ)[X] by a polynomial of the form 1+X+...+X^n for some n > \\epsilon*deg(f). We also formulate and prove an analogous statement for elliptic curves.

  12. Conjecture on the physical implications of the scale anomaly

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Christopher T.; /Fermilab

    2005-10-01

    Murray Gell-Mann, after co-inventing QCD, recognized the interplay of the scale anomaly, the renormalization group, and the origin of the strong scale, {Lambda}{sub QCD}. I tell a story, then elaborate this concept, and for the sake of discussion, propose a conjecture that the physical world is scale invariant in the classical, {h_bar}, limit. This principle has implications for the dimensionality of space-time, the cosmological constant, the weak scale, and Planck scale.

  13. Saari's conjecture for the restricted three-body problem

    Science.gov (United States)

    Roberts, G. E.; Melanson, L.

    2007-03-01

    Saari’s conjecture adapted to the restricted three-body problem is proven analytically using BKK theory. Specifically, we show that it is not possible for a solution of the planar, circular, restricted three-body problem to travel along a level curve of the amended potential function unless it is fixed at a critical point (one of the five libration points.) Due to the low dimension of the problem, our proof does not rely on the use of a computer.

  14. Eternal Chaotic Inflation is Prohibited by Weak Gravity Conjecture

    CERN Document Server

    Huang, Qing-Guo; Wang, Yi

    2007-01-01

    We investigate whether the eternal chaotic inflation can be achieved when the weak gravity conjecture is taken into account. We show that even the assisted chaotic inflation with potential $\\lambda\\phi^4$ or $m^2\\phi^2$ can not be eternal. The effective field theory description for the inflaton field breaks down before inflation reaches the eternal regime. We also find that the total number of e-folds is still bounded by the inflationary entropy for the assisted inflation.

  15. The History of the Total Chromatic Number Conjecture

    CERN Document Server

    Shahmohamad, Hossein

    2011-01-01

    The total chromatic number conjecture which has appeared in a few hundred articles and in numerous books thus far is now one of the classic mathematical unsolved problems. It appears that many authors coincidentally have attributed it to Professor M. Behzad and/or to Professor V. G. Vizing. Eventually after four decades, Professor A. Soifer investigated the origin of this conjecture; published his findings in The Mathematical Coloring Book - 2009; and stated that, "In my opinion this unquestionably merits the joint credit to Vizing and Behzad." After checking all the arguments presented and the blames cited, I decided to investigate the controversy stated in this book on my own. My findings which are presented in this report specifically signify the following two points. - M. Behzad is the sole author of the Total Chromatic Number Conjecture. - The wrong referrals provided by numerous authors over the last forty four years, to indicate Vizing's authorship, must be brought to the attention of the authors and r...

  16. Graph theory favorite conjectures and open problems 1

    CERN Document Server

    Hedetniemi, Stephen; Larson, Craig

    2016-01-01

    This is the first in a series of volumes, which provide an extensive overview of conjectures and open problems in graph theory. The readership of each volume is geared toward graduate students who may be searching for research ideas. However, the well-established mathematician will find the overall exposition engaging and enlightening. Each chapter, presented in a story-telling style, includes more than a simple collection of results on a particular topic. Each contribution conveys the history, evolution, and techniques used to solve the authors’ favorite conjectures and open problems, enhancing the reader’s overall comprehension and enthusiasm. The editors were inspired to create these volumes by the popular and well attended special sessions, entitled “My Favorite Graph Theory Conjectures," which were held at the winter AMS/MAA Joint Meeting in Boston (January, 2012), the SIAM Conference on Discrete Mathematics in Halifax (June,2012) and the winter AMS/MAA Joint meeting in Baltimore(January, 2014). In...

  17. What is the magnetic Weak Gravity Conjecture for axions

    Energy Technology Data Exchange (ETDEWEB)

    Hebecker, Arthur; Henkenjohann, Philipp [Institute for Theoretical Physics, University of Heidelberg (Germany); Witkowski, Lukas T. [APC, Universite Paris 7, CNRS/IN2P3, CEA/IRFU, Obs. de Paris, Sorbonne Paris Cite, Paris (France)

    2017-03-15

    The electric Weak Gravity Conjecture demands that axions with large decay constant f couple to light instantons. The resulting large instantonic corrections pose problems for natural inflation. We explore an alternative argument based on the magnetic Weak Gravity Conjecture for axions, which we try to make more precise. Roughly speaking, it demands that the minimally charged string coupled to the dual 2-form-field exists in the effective theory. Most naively, such large-f strings curve space too much to exist as static solutions, thus ruling out large-f axions. More conservatively, one might allow non-static string solutions to play the role of the required charged objects. In this case, topological inflation would save the superplanckian axion. Furthermore, a large-f axion may appear in the low-energy effective theory based on two subplanckian axions in the UV. The resulting effective string is a composite object built from several elementary strings and domain walls. It may or may not satisfy the magnetic Weak Gravity Conjecture depending on how strictly the latter is interpreted and on the cosmological dynamics of this composite object, which remain to be fully understood. Finally, we recall that large-field brane inflation is naively possible in the codimension-one case. We show how string-theoretic back-reaction closes this apparent loophole of large-f (non-periodic) pseudo-axions. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. On resolution to Wu's conjecture on Cauchy function's exterior singularities

    Institute of Scientific and Technical Information of China (English)

    Theodore Yaotsu Wu

    2011-01-01

    This is a series of studies on Wu's conjecture and on its resolution to be presented herein. Both are devoted to expound all the comprehensive properties of Cauchy's function f(z) (z = x + iy) and its integral J[∫(z)] = (2πi)-1 φ f(t)(t - z)-1dt taken along the unit circle as contour C, inside which (the open domain D+)f(z) is regular but has singularities distributed in open domain Doutside C. Resolution is given to the inverse problem that the singularities of f(z) can be determined in analytical form in terms of the values f(t) of f(z) numerically prescribed on C (|t| = 1), as so enunciated by Wu's conjecture. The case of a single singularity is solved using complex algebra and analysis to acquire the solution structure for a standard reference. Multiple singularities are resolved by reducing them to a single one by elimination in principle, for which purpose a general asymptotic method is developed here for resolution to the conjecture by induction, and essential singularities aretreated with employing the generalized Hilbert transforms.These new methods are applicable to relevant problems in mathematics, engineering and technology in analogy with resolving the inverse problem presented here.

  19. Weak Gravity Conjecture in AdS/CFT

    CERN Document Server

    Nakayama, Yu

    2015-01-01

    We study implications of the weak gravity conjecture in the AdS/CFT correspondence. Unlike in Minkowski spacetime, AdS spacetime has a physical length scale, so that the conjecture must be generalized with an additional parameter. We discuss possible generalizations and translate them into the language of dual CFTs, which take the form of inequalities involving the dimension and charge of an operator as well as the current and energy-momentum tensor central charges. We then test these inequalities against various CFTs to see if they are universally obeyed by all the CFTs. We find that certain CFTs, such as supersymmetric QCDs, do not satisfy them even in the large $N$ limit. This does not contradict the conjecture in AdS spacetime because the theories violating them are either unlikely or unclear to have weakly coupled gravitational descriptions, but it suggests that the CFT inequalities obtained here by naive translations do not apply beyond the regime in which weakly coupled gravitational descriptions are a...

  20. Human-robot interaction strategies for walker-assisted locomotion

    CERN Document Server

    Cifuentes, Carlos A

    2016-01-01

    This book presents the development of a new multimodal human-robot interface for testing and validating control strategies applied to robotic walkers for assisting human mobility and gait rehabilitation. The aim is to achieve a closer interaction between the robotic device and the individual, empowering the rehabilitation potential of such devices in clinical applications. A new multimodal human-robot interface for testing and validating control strategies applied to robotic walkers for assisting human mobility and gait rehabilitation is presented. Trends and opportunities for future advances in the field of assistive locomotion via the development of hybrid solutions based on the combination of smart walkers and biomechatronic exoskeletons are also discussed. .

  1. Dandy-Walker Malformation Presenting with Psychological Manifestations

    Directory of Open Access Journals (Sweden)

    Yasodha Maheshi Rohanachandra

    2016-01-01

    Full Text Available Dandy-Walker malformation, which is a congenital malformation of the cerebellum, is documented in literature to be associated with psychotic symptoms, obsessive compulsive symptoms, mood symptoms, hyperactivity, and impulsive behavior. The pathogenesis of psychiatric symptoms in Dandy-Walker malformation is thought to be due to disruption of the corticocerebellar tracts, resulting in what is known as cerebellar cognitive affective syndrome. We present a case of Dandy-Walker malformation presenting with psychiatric symptoms. This case highlights the necessity to be aware of psychiatric manifestations of cerebellar disease as it has an impact on the diagnosis and treatment.

  2. 78 FR 25234 - Proposed Establishment of Class E Airspace; Walker, MN

    Science.gov (United States)

    2013-04-30

    ... Federal Aviation Administration 14 CFR Part 71 Proposed Establishment of Class E Airspace; Walker, MN...: This action proposes to establish Class E airspace at Walker, MN. Controlled airspace is necessary to... radius to accommodate new standard instrument approach procedures at Walker Municipal Airport, Walker, MN...

  3. Parcels and Land Ownership, Published in 2011, Walker County Government.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Parcels and Land Ownership dataset as of 2011. The extent of these data is generally Walker County, TX. This metadata was auto-generated through the Ramona GIS...

  4. Interaction of two walkers: wave-mediated energy and force.

    Science.gov (United States)

    Borghesi, Christian; Moukhtar, Julien; Labousse, Matthieu; Eddi, Antonin; Fort, Emmanuel; Couder, Yves

    2014-12-01

    A bouncing droplet, self-propelled by its interaction with the waves it generates, forms a classical wave-particle association called a "walker." Previous works have demonstrated that the dynamics of a single walker is driven by its global surface wave field that retains information on its past trajectory. Here we investigate the energy stored in this wave field for two coupled walkers and how it conveys an interaction between them. For this purpose, we characterize experimentally the "promenade modes" where two walkers are bound and propagate together. Their possible binding distances take discrete values, and the velocity of the pair depends on their mutual binding. The mean parallel motion can be either rectilinear or oscillating. The experimental results are recovered analytically with a simple theoretical framework. A relation between the kinetic energy of the droplets and the total energy of the standing waves is established.

  5. Dandy-Walker variant associated with bipolar affective disorder

    Directory of Open Access Journals (Sweden)

    Anand Lingeswaran

    2009-01-01

    Full Text Available The Dandy-Walker malformation is a congenital brain malformation, typically involving the fourth ventricle and the cerebellum. To date, the Dandy-Walker syndrome has not been described in association with bipolar disorder type I mania, and therefore we briefly report the case of a Dandy-Walker variant associated with acute mania. A 10-year-old boy was brought by his mother to the outpatient clinic of the Department of Psychiatry of a tertiary care hospital, with symptoms of mania. The MRI brain of the patient showed a posterior fossa cystic lesion, a giant cisterna magna communicating with the fourth ventricle and mild hypoplasia of the cerebellar vermis, with the rest of the structures being normal and no signs of hydrocephalus. These findings showed that the patient had a Dandy-Walker variant. He responded partially to valproate and olanzepine, which controlled the acute manic symptoms in the ward.

  6. DANDY-WALKER MALFORMATION: A RARE CONGENITAL ANOMALY

    Directory of Open Access Journals (Sweden)

    Uroos

    2014-08-01

    Full Text Available Dandy Walker Malformation (DWM is a congenital malformation involving the cerebellum and fluid filled spaces around it. A key feature of this syndrome is partial or complete absence of a part of brain located between two cerebellar hemispheres ie. cerebellar vermis.(1 Dandy walker malformation was originally described in 1887 by Sutton and further characterized by Dandy and Blackfan in 1914 followed by Tagart and Walker in 1942. Benda finally labeled this disease as Dandy Walker in 1954. (2 Since the original description, additional studies have reported on various morphological features of this syndrome. It is a genetically sporadic disorder that occurs one in every 30,000live births. (3 Because of its rarity, here we report a case of DWM, in a fetus in which the diagnosis was made prenatally on USG. Later on, MTP was done by expulsion. Fetus was sent for autopsy to rule out other associated congenital abnormalities

  7. Lonomia obliqua Walker (Lepidoptera: Saturniidae: hemostasis implications

    Directory of Open Access Journals (Sweden)

    Silviane Maggi

    2015-06-01

    Full Text Available Summary In southern Brazil, since 1989, several cases of accidents produced by unwilling contact with the body of poisonous caterpillars of the moth species Lonomia obliqua Walker, 1855 (Lepidoptera: Saturniidae, were described. L. obliqua caterpillars have gregarious behavior and feed on leaves of host trees during the night, staying grouped in the trunk during the day, which favors the occurrence of accidents with the species. This caterpillar has the body covered with bristles that on contact with the skin of individuals, breaks and release their contents, inoculating the venom into the victim. The basic constitution of the venom is protein and its components produce physiological changes in the victim, which include disturbances in hemostasis. Hemorrhagic syndrome associated with consumption coagulopathy, intravascular hemolysis and acute renal failure are some of the possible clinical manifestations related to poisoning by L. obliqua. Specific laboratory tests for diagnosis of poisoning have not been described previously. The diagnosis of poisoning is made based on the patient's medical history, clinical manifestations, erythrocyte levels, and, primarily, parameters that evaluate blood coagulation. Treatment is performed with the use of supportive care and the administration of specific hyperimmune antivenom. Poisoning can be serious and even fatal.

  8. ACADEMIC TRAINING (R.P. Walker)

    CERN Multimedia

    Françoise Benz

    2002-01-01

    15, 16, 17 May LECTURE SERIES from 11.00 to 12.00 hrs - Council room, bldg. 503 on 15 May, Auditorium, bldg. 500 on 16 and 17 May Introduction to free electron lasers by R.P. Walker / Rutherford Laboratory, UK The Free-electron laser (FEL) is a source of coherent electromagnetic radiation based on a relativistic electron beam. First operated 25 years ago, the FEL has now reached a stage of maturity for operation in the infra-red region of the spectrum and several facilities provide intense FEL radiation beams for research covering a wide range of disciplines. Several projects both underway and proposed aim at pushing the minimum wavelength from its present limit around 100 nm progressively down to the 1 Angstrom region where the X-ray FEL would open up many new and exciting research possibilities. Other developments aim at increasing power levels to the 10's of kW level. In this series of lectures we give an introduction to the basic principles of FELs and their different modes of operation, and summarise the...

  9. Neurodevelopment in preschool idiopathic toe-walkers.

    Science.gov (United States)

    Martín-Casas, P; Ballestero-Pérez, R; Meneses-Monroy, A; Beneit-Montesinos, J V; Atín-Arratibel, M A; Portellano-Pérez, J A

    2017-09-01

    Idiopathic toe walking, a differential diagnosis for neurological and orthopaedic disorders, has been associated with neurodevelopmental alterations. Neurodevelopmental assessment at early ages using specific tests may improve management and follow-up of these patients. The aim of our study is to analyse the neurodevelopmental characteristics of preschool idiopathic toe-walkers (ITW) by comparing them to a control group. Our descriptive cross-sectional study compared possible risk factors, neurodevelopmental characteristics, and scores on the Child Neuropsychological Maturity Questionnaire (CUMANIN) between a group of 56 ITWs aged 3 to 6 and a control group including 40 children. The proportion of males was significantly higher in the ITW group (P=.008). The percentage of patients with a family history (P=.000) and biological risk factors during the perinatal period (P=.032) was also higher in this group. According to the parents' reports, motor coordination in ITWs was significantly poorer (59%; P=.009). ITWs scored significantly lower on CUMANIN subscales of psychomotricity (=0,001) and memory (P=.001), as well as in verbal development (P=.000), non-verbal development (P=.026), and overall development (P=.004). Foot preference was less marked in the ITW group (P=.047). The neurodevelopmental characteristics of our sample suggest that idiopathic toe walking is a marker of neurodevelopmental impairment. However, further studies are necessary to confirm these findings. Copyright © 2016 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. Mass neutrino oscillations in Robertson-Walker space-time

    Institute of Scientific and Technical Information of China (English)

    Huang Xiu-Ju; Li Ze-Jun; Wang Yong-Jiu

    2006-01-01

    Along the geodesic we calculate the interference phase of the mass neutrinos propagating in the radial direction in Robertson-Walker space-time. Since our universe is expanding, the phase factor Φ is increasing under the condition of the same proper physical distance l. Different values of curvature parameter k in Robertson-Walker metric represent different cosmological models, correspondingly, we obtain the different interference phases.

  11. The weak 3-flow conjecture and the weak circular flow

    DEFF Research Database (Denmark)

    Thomassen, Carsten

    2012-01-01

    We show that, for each natural number k>1, every graph (possibly with multiple edges but with no loops) of edge-connectivity at least 2k2+k has an orientation with any prescribed outdegrees modulo k provided the prescribed outdegrees satisfy the obvious necessary conditions. For k=3 the edge-conn...... proposed in 2006 by Bárat and Thomassen when restricted to stars. Finally, it is the currently strongest partial result on the (2+ϵ)-flow conjecture by Goddyn and Seymour....

  12. Quantum hoop conjecture: Black hole formation by particle collisions

    Energy Technology Data Exchange (ETDEWEB)

    Casadio, Roberto, E-mail: casadio@bo.infn.it [Dipartimento di Fisica e Astronomia, Università di Bologna, via Irnerio 46, 40126 Bologna (Italy); I.N.F.N., Sezione di Bologna, viale Berti Pichat 6/2, 40127 Bologna (Italy); Micu, Octavian, E-mail: octavian.micu@spacescience.ro [Institute of Space Science, Bucharest, P.O. Box MG-23, RO-077125 Bucharest-Magurele (Romania); Scardigli, Fabio, E-mail: fabio@phys.ntu.edu.tw [Dipartimento di Matematica, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milano (Italy); Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

    2014-05-01

    We address the issue of (quantum) black hole formation by particle collision in quantum physics. We start by constructing the horizon wave-function for quantum mechanical states representing two highly boosted non-interacting particles that collide in flat one-dimensional space. From this wave-function, we then derive a probability that the system becomes a black hole as a function of the initial momenta and spatial separation between the particles. This probability allows us to extend the hoop conjecture to quantum mechanics and estimate corrections to its classical counterpart.

  13. On a conjecture about inverse domination in graphs

    DEFF Research Database (Denmark)

    Frendrup, Allan; Henning, Michael A.; Randerath, Bert

    Let G = (V,E) be a graph with no isolated vertex. A classical observation in domination theory is that if D is a minimum dominating set of G, then V \\D is also a dominating set of G. A set D′ is an inverse dominating set of G if D′ is a dominating set of G and D′ ⊆ V \\D for some minimum dominating...... domination number of G is at most the independence number of G. We prove this conjecture for special families of graphs, including claw-free graphs, bipartite graphs, split graphs, very well covered graphs, chordal graphs and cactus graphs....

  14. On a Conjecture about Inverse Domination in Graphs

    DEFF Research Database (Denmark)

    Frendrup, Allan; Henning, Michael A.; Randerath, Bert

    2010-01-01

    Let G = (V, E) be a graph with no isolated vertex. A classical observation in domination theory is that if D is a minimum dominating set of G, then V \\ D is also a dominating set of G. A set D' is an inverse dominating set of G if D' is a dominating set of G and D' subset of V \\ D for some minimum...... domination number of G is at most the independence number of G. We prove this conjecture for special families of graphs, including claw-free graphs, bipartite graphs, split graphs, very well covered graphs, chordal graphs and cactus graphs....

  15. The stable moduli space of Riemann surfaces: Mumford's conjecture

    DEFF Research Database (Denmark)

    Madsen, I.; Weiss, Michael

    2007-01-01

    D. Mumford conjectured in "Towards an enumerative geometry of the moduli space of curves" that the rational cohomology of the stable moduli space of Riemann surfaces is a polynomial algebra generated by certain classes $\\kappa_i$ of dimension $2i$. For the purpose of calculating rational cohomology......, one may replace the stable moduli space of Riemann surfaces by $B\\Gamma_{\\infty}$, where $\\Gamma_\\infty$ is the group of isotopy classes of automorphisms of a smooth oriented connected surface of ``large'' genus. Tillmann's theorem that the plus construction makes $B\\Gamma_{\\infty}$ into an infinite...

  16. The quantum chaos conjecture and generalized continued fractions

    Science.gov (United States)

    Pustyl'nikov, L. D.

    2003-04-01

    The proof of the quantum chaos conjecture is given for a class of systems including as a special case the model of a rotating particle under the action of periodic impulse perturbations. (The distribution of the distances between adjacent energy levels is close to the Poisson distribution and differs from it by terms of the third order of smallness.) The proof reduces to a result in number theory on the distribution of the distances between adjacent fractional parts of values of a polynomial, while the estimate of the remainder term is based on the new theory of generalized continued fractions for vectors.

  17. Holomorphic Morse inequalities and the Green-Griffiths-Lang conjecture

    CERN Document Server

    Demailly, Jean-Pierre

    2010-01-01

    The goal of this work is to study the existence and properties of non constant entire curves f drawn in a complex irreducible n-dimensional variety X, and more specifically to show that they must satisfy certain global algebraic or differential equations as soon as X is projective of general type. By means of holomorphic Morse inequalities and a probabilistic analysis of the cohomology of jet spaces, we are able to reach a significant step towards a generalized version of the Green-Griffiths-Lang conjecture.

  18. Remarks on S. Lang's conjecture over function fields

    CERN Document Server

    Moriwaki, A

    1994-01-01

    In this short note, we will show the following weak evidence of S. Lang conjecture over function fields. Let f : X ---> Y be a projective and surjective morphism of algebraic varieties over an algebraically closed field k of characteristic zero, whose generic fiber is geometrically irreducible and of general type. If f is not birationally trivial, then there are countably many proper closed varieties { Z_i } of X such that every quasi-section of f is contained in the union of Z_i.

  19. On a problem in simultaneous Diophantine approximation: Schmidt's conjecture

    CERN Document Server

    Badziahin, Dzmitry; Velani, Sanju

    2010-01-01

    For any $i,j \\ge 0$ with $i+j =1$, let $\\bad(i,j)$ denote the set of points $(x,y) \\in \\R^2$ for which $ \\max \\{\\|qx\\|^{1/i}, \\|qy\\|^{1/j} \\} > c/q $ for all $ q \\in \\N $. Here $c = c(x,y)$ is a positive constant. Our main result implies that any finite intersection of such sets has full dimension. This settles a conjecture of Wolfgang M. Schmidt in the theory of simultaneous Diophantine approximation.

  20. Conjecture and hypothesis: The importance of reality checks

    Directory of Open Access Journals (Sweden)

    David Deamer

    2017-03-01

    Full Text Available In origins of life research, it is important to understand the difference between conjecture and hypothesis. This commentary explores the difference and recommends alternative hypotheses as a way to advance our understanding of how life can begin on the Earth and other habitable planets. As an example of how this approach can be used, two conditions have been proposed for sites conducive to the origin of life: hydrothermal vents in salty seawater, and fresh water hydrothermal fields associated with volcanic landmasses. These are considered as alternative hypotheses and the accumulating weight of evidence for each site is described and analyzed.

  1. Proofs of two conjectures on ternary weakly regular bent functions

    OpenAIRE

    Helleseth, Tor; Hollmann, Henk D. L.; Kholosha, Alexander; Wang, Zeying; Xiang, Qing

    2008-01-01

    We study ternary monomial functions of the form $f(x)=\\Tr_n(ax^d)$, where $x\\in \\Ff_{3^n}$ and $\\Tr_n: \\Ff_{3^n}\\to \\Ff_3$ is the absolute trace function. Using a lemma of Hou \\cite{hou}, Stickelberger's theorem on Gauss sums, and certain ternary weight inequalities, we show that certain ternary monomial functions arising from \\cite{hk1} are weakly regular bent, settling a conjecture of Helleseth and Kholosha \\cite{hk1}. We also prove that the Coulter-Matthews bent functions are weakly regular.

  2. Graph Edge Coloring Vizing's Theorem and Goldberg's Conjecture

    CERN Document Server

    Stiebitz, Michael; Toft, Bjarne; Favrholdt, Lene M

    2012-01-01

    Features recent advances and new applications in graph edge coloring Reviewing recent advances in the Edge Coloring Problem, Graph Edge Coloring: Vizing's Theorem and Goldberg's Conjecture provides an overview of the current state of the science, explaining the interconnections among the results obtained from important graph theory studies. The authors introduce many new improved proofs of known results to identify and point to possible solutions for open problems in edge coloring. The book begins with an introduction to graph theory and the concept of edge coloring. Subsequent chapters explor

  3. Knowledge space theory and union-closed sets conjecture

    Directory of Open Access Journals (Sweden)

    Chatchawan Panraksa

    2016-08-01

    Full Text Available The knowledge space theory provides a framework for knowledge management. One of major problems is to find core information for a body of knowledge. Union closed set conjecture, if true, guarantees that for a given knowledge space, there is an information that is linked to at least half of the knowledge units. This paper deals with a variant problem, where the knowledge space is also a topological space and possibly infinite. We prove that there is a point belonging to as many open sets as of the topological space itself.

  4. Marijuana (Weed, Pot) Facts

    Science.gov (United States)

    ... That People Abuse » Marijuana (Weed, Pot) Facts Marijuana (Weed, Pot) Facts Listen Marijuana is a green, brown, or gray mix of dried, shredded leaves and flowers from the marijuana plant. Marijuana can be rolled up and smoked ...

  5. Zika Virus Fact Sheet

    Science.gov (United States)

    ... sheets Fact files Questions & answers Features Multimedia Contacts Zika virus Fact sheet Updated 6 September 2016 Key ... and last for 2-7 days. Complications of Zika virus disease Based on a systematic review of ...

  6. Facts about Amblyopia

    Science.gov (United States)

    ... Health Information > Amblyopia > Facts About Amblyopia Facts About Amblyopia This information was developed by the National Eye ... is the best person to answer specific questions. Amblyopia Defined What is amblyopia? The brain and the ...

  7. Cholesterol Facts and Statistics

    Science.gov (United States)

    ... Blood Pressure Salt Million Hearts® WISEWOMAN Program High Cholesterol Facts Recommend on Facebook Tweet Share Compartir As ... the facts about high cholesterol [PDF-281K] . High Cholesterol in the United States 73.5 million adults ( ...

  8. Trauma Fact Sheet

    Science.gov (United States)

    ... Home > Science Education > Physical Trauma Fact Sheet Physical Trauma Fact Sheet Tagline (Optional) Middle/Main Content Area ... of physical trauma. Credit: iStock. What is physical trauma? Physical trauma is a serious injury to the ...

  9. Diabetes Fact Sheet

    Science.gov (United States)

    ... diabetes by losing weight. Related information Fitness and nutrition Heart disease and stroke Obesity and weight loss fact sheet Physical activity fact sheet Pregnancy The javascript used in this widget is not ...

  10. Organ Facts: Pancreas

    Science.gov (United States)

    ... Lung Kidney Pancreas Kidney/Pancreas Liver Intestine Pancreas Facts The pancreas is a five to six inch ... Camps for kids Contacting my donor family Data Facts about living donation Financing a transplant Matching organs ...

  11. Facts about Type 2

    Medline Plus

    Full Text Available ... Text Size: A A A Listen En Español Facts About Type 2 Type 2 diabetes is the ... 2, In this section Diabetes Basics Type 2 Facts About Type 2 Recently Diagnosed Treatment and Care ...

  12. Meningitis Myths and Facts

    Science.gov (United States)

    ... Diseases Infographic Prevention and Control of Meningococcal Disease Meningitis Myths and Facts Myth: Meningococcal disease is easy ... infected person, such as shaking hands. Fact: Meningococcal meningitis is spread through air droplets and direct contact ...

  13. Proof of the cosmic no-hair conjecture in the T^3-Gowdy symmetric Einstein-Vlasov setting

    CERN Document Server

    Andréasson, Håkan

    2013-01-01

    The currently preferred models of the universe undergo accelerated expansion induced by dark energy. One model for dark energy is a positive cosmological constant. It is consequently of interest to study Einstein's equations with a positive cosmological constant coupled to matter satisfying the ordinary energy conditions; the dominant energy condition etc. Due to the difficulty of analysing the behaviour of solutions to Einstein's equations in general, it is common to either study situations with symmetry, or to prove stability results. In the present paper, we do both. In fact, we analyse, in detail, the future asymptotic behaviour of T^3-Gowdy symmetric solutions to the Einstein-Vlasov equations with a positive cosmological constant. In particular, we prove the cosmic no-hair conjecture in this setting. However, we also prove that the solutions are future stable (in the class of all solutions). Some of the results hold in a more general setting. In fact, we obtain conclusions concerning the causal structure...

  14. On a conjecture of compatibility of multi-states characters

    CERN Document Server

    Habib, Michel

    2011-01-01

    Perfect phylogeny consisting of determining the compatibility of a set of characters is known to be NP-complete. We propose in this article a conjecture on the necessary and sufficient conditions of compatibility: Given a set $\\mathcal{C}$ of $r$-states full characters, there exists a function $f(r)$ such that $\\mathcal{C}$ is compatible iff every set of $f(r)$ characters of $\\mathcal{C}$ is compatible. Some previous work showed that $f(2)=2$, $f(3)=3$ and $f(r) \\ge r-1$. Gusfield et al. 09 conjectured that $f(r) = r$ for any $r \\ge 2$. In this paper, we present an example showing that $f(4) \\ge 5$ and then a closure operation for chordal sandwich graphs. The later problem is a common approach of perfect phylogeny. This operation can be the first step to simplify the problem before solving some particular cases $f(4), f(5), ... $, and determining the function $f(r)$.

  15. Facts about Hib Disease. ARC Facts.

    Science.gov (United States)

    Association for Retarded Citizens, Arlington, TX.

    The fact sheet provides basic information about Hib Disease in young children, which may involve a bacterial meningitis causing mental retardation, hearing loss, partial blindness, speech disorders, partial paralysis, behavioral problems, or seizures. Stressed is prevention of Hib Disease through immunization. The question and answer format…

  16. Facts about Hib Disease. ARC Facts.

    Science.gov (United States)

    Association for Retarded Citizens, Arlington, TX.

    The fact sheet provides basic information about Hib Disease in young children, which may involve a bacterial meningitis causing mental retardation, hearing loss, partial blindness, speech disorders, partial paralysis, behavioral problems, or seizures. Stressed is prevention of Hib Disease through immunization. The question and answer format…

  17. A Counterexample to a Generalized Saari's Conjecture with a Continuum of Central Configurations

    CERN Document Server

    Santoprete, Manuele

    2009-01-01

    In this paper we show that in the $n$-body problem with harmonic potential one can find a continuum of central configurations for $n=3$. Moreover we show a counterexample to an interpretation of Jerry Marsden Generalized Saari's conjecture. This will help to refine our understanding and formulation of the Generalized Saari's conjecture, and in turn it might provide insight in how to solve the classical Saari's conjecture for $n\\geq 4$.

  18. On the coefficient conjecture of Clunie and Sheil-Small on univalent harmonic mappings

    Indian Academy of Sciences (India)

    S Ponnusamy; A Sairam Kaliraj

    2015-08-01

    In this paper, we first prove the coefficient conjecture of Clunie and Sheil-Small for a class of univalent harmonic functions which includes functions convex in some direction. Next, we prove growth and covering theorems and some related results. Finally, we propose two conjectures, an affirmative answer to one of which would then imply, for example, a solution to the conjecture of Clunie and Sheil-Small.

  19. Embeddings, immersions and the Bartnik quasi-local mass conjectures

    CERN Document Server

    Anderson, Michael T

    2016-01-01

    Given a Riemannian 3-ball $(B, g)$ of non-negative scalar curvature, Bartnik conjectured that $(B, g)$ admits an asymptotically flat (AF) extension (without horizons) of the least possible ADM mass, and that such a mass-minimizer is an AF solution to the static vacuum Einstein equations, uniquely determined by natural geometric conditions on the boundary data of $(B, g)$. We prove the validity of the second statement, i.e. such mass-minimizers, if they exist, are indeed AF solutions of the static vacuum equations. On the other hand, we prove that the first statement is not true in general; there is a rather large class of bodies $(B, g)$ for which a minimal mass extension does not exist.

  20. Hoop Conjecture and Black Holes on a Brane

    CERN Document Server

    Nakamura, K; Mishima, T; Nakamura, Kouji; Nakao, Ken-ichi; Mishima, Takeshi

    2003-01-01

    The initial data of gravity for a cylindrical matter distribution confined to a brane are studied in the framework of the single-brane Randall-Sundrum scenario. In this scenario, the 5-dimensional nature of gravity appears in the short-range gravitational interaction. We find that a sufficiently thin configuration of matter leads to the formation of a marginal surface, even if the configuration is infinitely long. This implies that the hoop conjecture proposed by Thorne does not hold on the brane: Even if a mass $M$ does not become compacted into a region whose circumference ${\\cal C}$ in every direction satisfies ${\\cal C}> 4\\pi GM$, black holes with horizons can form in the Randall-Sundrum scenario.

  1. Hoop Conjecture and Cosmic Censorship in the Brane-World

    CERN Document Server

    Nakao, K; Mishima, T; Nakao, Ken-ichi; Nakamura, Kouji; Mishima, Takashi

    2003-01-01

    The initial data of gravity for a cylindrical matter distribution confined on the brane is studied in the framework of the single brane Randall-Sundrum scenario. In this scenario, 5-dimensional aspect of gravity appears in the short range gravitational interaction. We found that the sufficiently thin configuration of matter leads to the formation of the marginal surface even if the configuration is infinitely long. This means that the hoop conjecture proposed by Thorne does not hold in the Randall-Sundrum scenario; Even if a mass $M$ does not get compacted into a region whose circumference in every direction is ${\\cal C}\\le 4\\pi GM$, black holes with horizons can form in the Randall-Sundrum scenario.

  2. Tryon's conjecture and Energy and momentum of Bianchi Type Universes

    CERN Document Server

    Mishra, Prajyot Kumar; Pattanayak, Pradosh Ranjan; Tripathy, Sunil Kumar

    2016-01-01

    The energy and momentum of the Bianchi type $III$ universes are obtained using different prescriptions for the energy-momentum complexes in the framework of General Relativity. The energy and momentum of the Bianchi $III$ universe is found to be zero for the M\\o{}ller prescription. For all other prescriptions the energy and momentum vanish when the metric parameter $h$ vanishes. In an earlier work, Tripathy et al. \\cite{SKT15} have obtained the energy and momentum of Bianchi $VI_h$ metric and found that the energy of the Universe vanish only for $h=-1$. This result raised a question: why this specific choice?. We explored the Tryon's conjecture that 'the Universe must have a zero net value for all conserved quantities' to get some ideas on the specific values of this parameter for Bianchi type Universes.

  3. Sums of hermitian squares and the BMV conjecture

    CERN Document Server

    Klep, Igor

    2007-01-01

    Recently Lieb and Seiringer showed that the Bessis-Moussa-Villani conjecture from quantum physics can be restated in the following purely algebraic way: The sum of all words in two positive semidefinite matrices where the number of each of the two letters is fixed is always a matrix with nonnegative trace. We show that this statement holds if the words are of length at most 13. This has previously been known only up to length 7. In our proof, we establish a connection to sums of hermitian squares of polynomials in noncommuting variables and to semidefinite programming. As a by-product we obtain an example of a real polynomial in two noncommuting variables having nonnegative trace on all symmetric matrices of the same size, yet not being a sum of hermitian squares and commutators.

  4. Representations of unipotent groups over local fields and Gutkin's conjecture

    CERN Document Server

    Boyarchenko, Mitya

    2010-01-01

    Let F be a finite field or a local field of any characteristic. If A is a finite dimensional associative nilpotent algebra over F, the set 1+A of all formal expressions of the form 1+x, where x ranges over the elements of A, is a locally compact group with the topology induced by the standard one on F and the multiplication given by (1+x)(1+y)=1+(x+y+xy). We prove a result conjectured by Eugene Gutkin in 1973: every unitary irreducible representation of 1+A can be obtained by unitary induction from a 1-dimensional unitary character of a subgroup of the form 1+B, where B is an F-subalgebra of A. In the case where F is local and nonarchimedean we also establish an analogous result for smooth irreducible representations of 1+A over the field of complex numbers and show that every such representation is admissible and carries an invariant Hermitian inner product.

  5. A Holographic Entanglement Entropy Conjecture for General Spacetimes

    CERN Document Server

    Sanches, Fabio

    2016-01-01

    We present a natural generalization of holographic entanglement entropy proposals beyond the scope of AdS/CFT by anchoring extremal surfaces to holographic screens. Holographic screens are a natural extension of the AdS boundary to arbitrary spacetimes and are preferred codimension 1 surfaces from the viewpoint of the covariant entropy bound. Screens have a unique preferred foliation into codimension 2 surfaces called leaves. Our proposal is to find the areas of extremal surfaces achored to the boundaries of regions in leaves. We show that the properties of holographic screens are sufficient to prove, under generic conditions, that extremal surfaces anchored in this way always lie within a causal region associated with a given leaf. Within this causal region, a maximin construction similar to that of Wall proves that our proposed quantity satisfies standard properties of entanglement entropy like strong subadditivity. We conjecture that our prescription computes entanglement entropies in quantum states that h...

  6. Spectral Duality in Integrable Systems from AGT Conjecture

    CERN Document Server

    Mironov, A; Zenkevich, Y; Zotov, A

    2012-01-01

    We describe relationships between integrable systems with N degrees of freedom arising from the AGT conjecture. Namely, we prove the equivalence (spectral duality) between the N-cite Heisenberg spin chain and a reduced gl(N) Gaudin model both at classical and quantum level. The former one appears on the gauge theory side of the AGT relation in the Nekrasov-Shatashvili (and further the Seiberg-Witten) limit while the latter one is natural on the CFT side. At the classical level, the duality transformation relates the Seiberg-Witten differentials and spectral curves via a bispectral involution. The quantum duality extends this to the equivalence of the corresponding Baxter-Schrodinger equations (quantum spectral curves). This equivalence generalizes both the spectral self-duality between the 2x2 and NxN representations of the Toda chain and the famous AHH duality.

  7. The swampland conjecture and F-term axion monodromy inflation

    Science.gov (United States)

    Blumenhagen, Ralph; Valenzuela, Irene; Wolf, Florian

    2017-07-01

    We continue the investigation of F-term axion monodromy inflation in string theory, while seriously taking the issue of moduli stabilization into account. For a number of closed and open string models, we show that they suffer from serious control issues once one is trying to realize trans-Planckian field excursions. More precisely, the flux tuning required to delay the logarithmic scaling of the field distance to a trans-Planckian value cannot be done without leaving the regime where the employed effective supergravity theory is under control. Our findings are consistent with the axionic extension of the Refined Swampland Conjecture, stating that in quantum gravity the effective theory breaks down for a field excursion beyond the Planck scale. Our analysis suggests that models of F-term axion monodromy inflation with a tensor-to-scalar ratio r ≥ O(10-3) cannot be parametrically controlled.

  8. Notes on the proof of the KKV conjecture

    CERN Document Server

    Pandharipande, R

    2014-01-01

    The Katz-Klemm-Vafa conjecture expresses the Gromov-Witten theory of K3 surfaces (and K3-fibred 3-folds in fibre classes) in terms of modular forms. Its recent proof gives the first non-toric geometry in dimension greater than 1 where Gromov-Witten theory is exactly solved in all genera. We survey the various steps in the proof. The MNOP correspondence and a new Pairs/Noether-Lefschetz correspondence for K3-fibred 3-folds transform the Gromov-Witten problem into a calculation of the full stable pairs theory of a local K3-fibred 3-fold. The stable pairs calculation is then carried out via degeneration, localisation, vanishing results, and new multiple cover formulae.

  9. A Comment on Quantum Distribution Functions and the OSV Conjecture

    CERN Document Server

    Gómez, C; Gomez, Cesar; Montanez, Sergio

    2006-01-01

    Using the attractor mechanism and the relation between the quantization of $H^{3}(M)$ and topological strings on a Calabi Yau threefold $M$ we define a map from BPS black holes into coherent states. This map allows us to represent the Bekenstein-Hawking-Wald entropy as a quantum distribution function on the phase space $H^{3}(M)$. This distribution function is a mixed Husimi/anti-Husimi distribution corresponding to the different normal ordering prescriptions for the string coupling and deviations of the complex structure moduli. From the integral representation of this distribution function in terms of the Wigner distribution we recover the Ooguri-Strominger-Vafa (OSV) conjecture in the region "at infinity" of the complex structure moduli space. The physical meaning of the OSV corrections are briefly discussed in this limit.

  10. A comment on quantum distribution functions and the OSV conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Cesar [Instituto de Fisica Teorica CSIC/UAM, C-XVI Universidad Autonoma, E-28049 Madrid (Spain); Montanez, Sergio [Instituto de Fisica Teorica CSIC/UAM, C-XVI Universidad Autonoma, E-28049 Madrid (Spain)

    2006-12-15

    Using the attractor mechanism and the relation between the quantization of H{sup 3}(M) and topological strings on a Calabi Yau threefold M we define a map from BPS black holes into coherent states. This map allows us to represent the Bekenstein-Hawking-Wald entropy as a quantum distribution function on the phase space H{sup 3}(M). This distribution function is a mixed Husimi/anti-Husimi distribution corresponding to the different normal ordering prescriptions for the string coupling and deviations of the complex structure moduli. From the integral representation of this distribution function in terms of the Wigner distribution we recover the Ooguri-Strominger-Vafa (OSV) conjecture in the region 'at infinity' of the complex structure moduli space. The physical meaning of the OSV corrections are briefly discussed in this limit.

  11. The mixed Littlewood conjecture for pseudo-absolute values

    CERN Document Server

    Harrap, Stephen

    2010-01-01

    In this paper we prove the mixed Littlewood conjecture for a p-adic absolute value and any pseudo-absolute value with bounded ratios. More precisely we show that if p is a prime and D is a pseudo-absolute value sequence with elements divisible by finitely many primes not equal to p, and if the terms of D grow more slowly than the exponential of a polynomial then the infimum over natural numbers n of the quantity n.|n|_p.|n|_D.||nx|| equals 0 for all real x. Our proof relies on two deep results, a measure rigidity theorem due to Lindenstrauss and lower bounds for linear forms in logarithms due to Baker and Wustholz. We also deduce the answer to the related metric question of how fast the infimum above tends to zero, for almost every x.

  12. Investigation of the conjectured nucleon deformation at low momentum transfer

    CERN Document Server

    Sparveris, N F; Bernstein, A M; Bertozzi, W; Botto, T; Bourgeois, P; Calarco, J; Casagrande, F; Distler, M O; Dow, K; Farkondeh, M; Georgakopoulos, S V; Gilad, S; Hicks, R; Holtrop, M; Hotta, A; Jiang, X; Karabarbounis, A; Kirkpatrick, J; Kowalski, S; Milner, R; Miskimen, R; Nakagawa, I; Papanicolas, C N; Sarty, A J; Sato, Y; Sirca, S; Shaw, J; Six, E; Stave, S; Stiliaris, E; Tamae, T; Tsentalovich, G; Tschalär, C; Turchinetz, W E; Zhou, Z L; Zwart, T

    2004-01-01

    We report new precise H$(e,e^\\prime p)\\pi^0$ measurements at the $\\Delta(1232)$ resonance at $Q^2= 0.127$ (GeV/c)$^2$ using the MIT/Bates out-of-plane scattering (OOPS) facility. The data reported here are particularly sensitive to the transverse electric amplitude ($E2$) of the $\\gamma^* N\\to\\Delta$ transition. Analyzed together with previous data yield precise quadrupole to dipole amplitude ratios $EMR = (-2.3 \\pm 0.3_{stat+sys} \\pm 0.6_{model})%$ and $CMR = (-6.1 \\pm 0.2_{stat+sys}\\pm 0.5_{model})%$ and for $M^{3/2}_{1+} = (41.4 \\pm 0.3_{stat+sys}\\pm 0.4_{model})(10^{-3}/m_{\\pi^+})$. They give credence to the conjecture of deformation in hadronic systems favoring, at low $Q^2$, the dominance of mesonic effects.

  13. Notes on Ding-Iohara algebra and AGT conjecture

    CERN Document Server

    Awata, H; Hoshino, A; Kanai, M; Shiraishi, J; Yanagida, S

    2011-01-01

    We study the representation theory of the Ding-Iohara algebra $\\calU$ to find $q$-analogues of the Alday-Gaiotto-Tachikawa (AGT) relations. We introduce the endomorphism $T(u,v)$ of the Ding-Iohara algebra, having two parameters $u$ and $v$. We define the vertex operator $\\Phi(w)$ by specifying the permutation relations with the Ding-Iohara generators $x^\\pm(z)$ and $\\psi^\\pm(z)$ in terms of $T(u,v)$. For the level one representation, all the matrix elements of the vertex operators with respect to the Macdonald polynomials are factorized and written in terms of the Nekrasov factors for the $K$-theoretic partition functions as in the AGT relations. For higher levels $m=2,3,...$, we present some conjectures, which imply the existence of the $q$-analogues of the AGT relations.

  14. Conjectures regarding kissing spheres hierarchy and quantum gravity unification

    Energy Technology Data Exchange (ETDEWEB)

    El Naschie, M.S. [Department of Astrophysics, University of Cairo (Egypt); Donghua University Shanghai (China)], E-mail: Chaossf@aol.com

    2008-01-15

    Conjectures regarding connections between hyper-spheres kissing problems in one- to eight-dimensional spaces and the inverse coupling constant of quantum gravity are presented. In particular we demonstrate that in S{sup (7)} and S{sup (8)} the coupling constants of the non-super-symmetric and the super-symmetric unification are given by {alpha}-bar{sub g}={sup 7}{radical}(K(128)){approx_equal}42 and {alpha}-bar{sub gs}={sup 8}{radical}(K(128)){approx_equal}26 respectively where K(128) {approx_equal} (2.18)(10){sup 11} is the sphere kissing number in D = 128 Euclidian space.

  15. Global Units modulo Circular Units : descent without Iwasawa's Main Conjecture

    CERN Document Server

    Belliard, Jean-Robert

    2009-01-01

    Iwasawa's classical asymptotical formula relates the orders of the $p$-parts $X_n$ of the ideal class groups along a $\\ZM_p$-extension $F_\\infty/F$ of a number field $F$, to Iwasawa structural invariants $\\la$ and $\\mu$ attached to the inverse limit $X_\\infty=\\limpro X_n$. It relies on "good" descent properties satisfied by $X_n$. If $F$ is abelian and $F_\\infty$ is cyclotomic it is known that the $p$-parts of the orders of the global units modulo circular units $U_n/C_n$ are asymptotically equivalent to the $p$-parts of the ideal class numbers. This suggests that these quotients $U_n/C_n$, so to speak unit class groups, satisfy also good descent properties. We show this directly, i.e. without using Iwasawa's Main Conjecture.

  16. Walker 256 Tumor Growth Suppression by Crotoxin Involves Formyl Peptide Receptors and Lipoxin A4

    Science.gov (United States)

    Brigatte, Patrícia; Faiad, Odair Jorge; Ferreira Nocelli, Roberta Cornélio; Landgraf, Richardt G.; Palma, Mario Sergio; Cury, Yara; Curi, Rui; Sampaio, Sandra Coccuzzo

    2016-01-01

    We investigated the effects of Crotoxin (CTX), the main toxin of South American rattlesnake (Crotalus durissus terrificus) venom, on Walker 256 tumor growth, the pain symptoms associated (hyperalgesia and allodynia), and participation of endogenous lipoxin A4. Treatment with CTX (s.c.), daily, for 5 days reduced tumor growth at the 5th day after injection of Walker 256 carcinoma cells into the plantar surface of adult rat hind paw. This observation was associated with inhibition of new blood vessel formation and decrease in blood vessel diameter. The treatment with CTX raised plasma concentrations of lipoxin A4 and its natural analogue 15-epi-LXA4, an effect mediated by formyl peptide receptors (FPRs). In fact, the treatment with Boc-2, an inhibitor of FPRs, abolished the increase in plasma levels of these mediators triggered by CTX. The blockage of these receptors also abolished the inhibitory action of CTX on tumor growth and blood vessel formation and the decrease in blood vessel diameter. Together, the results herein presented demonstrate that CTX increases plasma concentrations of lipoxin A4 and 15-epi-LXA4, which might inhibit both tumor growth and formation of new vessels via FPRs. PMID:27190493

  17. Walker-Warburg syndrome: a report of 3 cases.

    Science.gov (United States)

    Denis, D; Gambarelli, D; Luciani, A; Aymé, S; Philip, N; Saracco, J B

    1993-01-01

    Walker-Warburg syndrome is a congenital malformation syndrome of unknown etiology which is characterized by fatal neurological lesions. It was first described by Walker in 1942 as involving agyria, hydrocephalus and eye malformations. Its etiology has been discussed in all of the articles on the subject in the literature, but the majority of the authors describe it as an autosomal recessive syndrome. Ultrasonography plays a key role in detecting a cephalic anomaly by prenatal diagnosis as in our 2 cases. The aim of this article is to report 3 new cases of Walker-Warburg syndrome in two families. Knowledge of this syndrome emphasizes both the need for ultrasonographic observation and genetic counselling for families at risk.

  18. Meth (Crank, Ice) Facts

    Science.gov (United States)

    ... That People Abuse » Meth (Crank, Ice) Facts Meth (Crank, Ice) Facts Listen Methamphetamine—meth for short—is a white, bitter powder. Sometimes ... clear or white shiny rock (called a crystal). Meth powder can be eaten or snorted up the ...

  19. Assessing Basic Fact Fluency

    Science.gov (United States)

    Kling, Gina; Bay-Williams, Jennifer M.

    2014-01-01

    In this article, the authors share a variety of ways to formatively assess basic fact fluency. The define fluency, raise some issues related to timed testing, and then share a collection of classroom-tested ideas for authentic fact fluency assessment. This article encourages teachers to try a variety of alternative assessments from this sampling,…

  20. Facts for Feeding Series.

    Science.gov (United States)

    Academy for Educational Development, Washington, DC.

    This document compiles several fact sheets, in multiple languages, for mothers and parent educators providing information and answering questions concerning breastfeeding infants. The fact sheets are published in English, French, and Spanish, and cover the following topics: (1) "Recommended Practices To Improve Infant Nutrition during the…

  1. Twentieth century Walker Circulation change: data analysis and model experiments

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Qingjia [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); Chinese Research Academy of Environmental Sciences, River and Coastal Environment Research Center, Beijing (China); Chinese Academy of Sciences, Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Qingdao (China); Latif, Mojib; Park, Wonsun; Keenlyside, Noel S.; Martin, Thomas [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); Semenov, Vladimir A. [Leibniz-Institut fuer Meereswissenschaften, Kiel (Germany); A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow (Russian Federation)

    2012-05-15

    Recent studies indicate a weakening of the Walker Circulation during the twentieth century. Here, we present evidence from an atmospheric general circulation model (AGCM) forced by the history of observed sea surface temperature (SST) that the Walker Circulation may have intensified rather than weakened. Observed Equatorial Indo-Pacific Sector SST since 1870 exhibited a zonally asymmetric evolution: While the eastern part of the Equatorial Pacific showed only a weak warming, or even cooling in one SST dataset, the western part and the Equatorial Indian Ocean exhibited a rather strong warming. This has resulted in an increase of the SST gradient between the Maritime Continent and the eastern part of the Equatorial Pacific, one driving force of the Walker Circulation. The ensemble experiments with the AGCM, with and without time-varying external forcing, suggest that the enhancement of the SST gradient drove an anomalous atmospheric circulation, with an enhancement of both Walker and Hadley Circulation. Anomalously strong precipitation is simulated over the Indian Ocean and anomalously weak precipitation over the western Pacific, with corresponding changes in the surface wind pattern. Some sensitivity to the forcing SST, however, is noticed. The analysis of twentieth century integrations with global climate models driven with observed radiative forcing obtained from the Coupled Model Intercomparison Project (CMIP) database support the link between the SST gradient and Walker Circulation strength. Furthermore, control integrations with the CMIP models indicate the existence of strong internal variability on centennial timescales. The results suggest that a radiatively forced signal in the Walker Circulation during the twentieth century may have been too weak to be detectable. (orig.)

  2. Casimir densities for a boundary in Robertson-Walker spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Saharian, A.A., E-mail: saharian@ictp.i [Department of Physics, Yerevan State University, 1 Alex Manoogian Street, 0025 Yerevan (Armenia); Setare, M.R., E-mail: rezakord@ipm.i [Department of Science of Bijar, University of Kurdistan, Bijar (Iran, Islamic Republic of)

    2010-04-12

    For scalar and electromagnetic fields we evaluate the vacuum expectation value of the energy-momentum tensor induced by a curved boundary in the Robertson-Walker spacetime with negative spatial curvature. In order to generate the vacuum densities we use the conformal relation between the Robertson-Walker and Rindler spacetimes and the corresponding results for a plate moving by uniform proper acceleration through the Fulling-Rindler vacuum. For the general case of the scale factor the vacuum energy-momentum tensor is presented as the sum of the boundary free and boundary induced parts.

  3. Dandy-Walker anomaly in Meckel-Gruber syndrome.

    Science.gov (United States)

    Cincinnati, P; Neri, M E; Valentini, A

    2000-01-01

    We report a fetus affected by Meckel-Gruber syndrome whose phenotype was characterized by macrocephaly, frontal bossing, a saddle nose, marked micrognathia, a distended abdomen, omphalocele, post-axial polydactyly and talipes equinovarus. The main neuropathological finding at autopsy was in a very large cyst located in an abnormally wide posterior cranial fossa consistent with a Dandy-Walker anomaly. Intestinal malrotation, enlarged cystic dysplastic kidneys and hepatic portal fibrosis coexisted. The occurrence of a Dandy-Walker malformation in Meckel-Gruber syndrome confirms a disturbance in rhombencephalon development. Although uncommon, it should be included among the central nervous anomalies representative of the syndrome.

  4. A proof of the Geroch-Horowitz-Penrose formulation of the strong cosmic censor conjecture motivated by computability theory

    CERN Document Server

    Etesi, Gabor

    2012-01-01

    In this paper we present a proof of a mathematical version of the strong cosmic censor conjecture attributed to Geroch-Horowitz and Penrose but formulated explicitly by Wald. The proof is based on the existence of future-inextendible causal curves in causal pasts of events on the future Cauchy horizon in a non-globally hyperbolic space-time.By examining explicit non-globally hyperbolic space-times we find that in case of several physically relevant solutions these future-inextendible curves have in fact infinite length. This way we recognize a close relationship between asymptotically flat or anti-de Sitter, physically relevant extendible space-times and the so-called Malament-Hogarth space-times which play a central role in recent investigations in the theory of "gravitational computers". This motivates us to exhibit a more sharp, more geometric formulation of the strong cosmic censor conjecture, namely "all physically relevant, asymptotically flat or anti-de Sitter but non-globally hyperbolic space-times ar...

  5. On the Beilinson-Hodge conjecture for $H^2$ and rational varieties

    CERN Document Server

    Chatzistamatiou, Andre

    2011-01-01

    The Beilinson-Hodge conjecture asserts the surjectivity of the cycle map $$H^n_M(X,\\Q(n)) \\to {\\rm Hom}_{MHS}(\\Q(-n),H^n(X,\\Q))$$ for all positive integers $n$ and every smooth complex algebraic variety $X$. For $n=2$, we prove the conjecture if $X$ is rational.

  6. The bounded isometry conjecture for the Kodaira-Thurston manifold and 4-Torus

    CERN Document Server

    Han, Zhigang

    2007-01-01

    The purpose of this note is to study the bounded isometry conjecture proposed by Lalonde and Polterovich. In particular, we show that the conjecture holds for the Kodaira-Thurston manifold with the standard symplectic form and for the 4-torus with all linear symplectic forms.

  7. Modelling of and Conjecturing on a Soccer Ball in a Korean Eighth Grade Mathematics Classroom

    Science.gov (United States)

    Lee, Kyeong-Hwa

    2011-01-01

    The purpose of this article was to describe the task design and implementation of cultural artefacts in a mathematics lesson based on the integration of modelling and conjecturing perspectives. The conceived process of integrating a soccer ball into mathematics lessons via modelling- and conjecturing-based instruction was first detailed. Next, the…

  8. Proof of an entropy conjecture for Bloch coherent spin states and its generalizations

    DEFF Research Database (Denmark)

    H. Lieb, Elliott; Solovej, Jan Philip

    2014-01-01

    in 1978 who also extended the conjecture to Bloch SU(2) spin-coherent states for every angular momentum $J$. This conjecture is proved here. We also recall our 1991 extension of the Wehrl map to a quantum channel from $J$ to $K=J+1/2, J+1, ...$, with $K=\\infty$ corresponding to the Wehrl map to classical...

  9. A Proof of George Andrews' and David Robbins' $q$-TSPP Conjecture

    CERN Document Server

    Koutschan, Christoph; Zeilberger, Doron

    2010-01-01

    The conjecture that the orbit-counting generating function for totally symmetric plane partitions can be written as an explicit product-formula, has been stated independently by George Andrews and David Robbins around 1983. We present a proof of this long-standing conjecture.

  10. Notes from the Underground: A Propos of Givental's Conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yun S.

    2001-04-11

    These brief notes record our puzzles and findings surrounding Givental's recent conjecture which expresses higher genus Gromov-Witten invariants in terms of the genus-0 data. We limit our considerations to the case of a projective line, whose Gromov-Witten invariants are well-known and easy to compute. We make some simple checks supporting his conjecture.

  11. Verification of the Firoozbakht conjecture for primes up to four quintillion

    OpenAIRE

    Kourbatov, Alexei

    2015-01-01

    If $p_k$ is the k-th prime, the Firoozbakht conjecture states that the sequence $(p_k)^{1/k}$ is strictly decreasing. We use the table of first-occurrence prime gaps in combination with known bounds for the prime-counting function to verify the Firoozbakht conjecture for primes up to four quintillion $(4\\times10^{18})$.

  12. The Erd(o)s-Sós Conjecture for Graphs Whose Complements Contain No C4

    Institute of Scientific and Technical Information of China (English)

    Jian-hua Yin; Jiong-sheng Li

    2004-01-01

    Erd(o)s and Sós conjectured in 1963 (see [1], Problem 12 in 247) that every graph G on n vertices with size e(G) > 12 n(k - 1) contains every tree T of size k. In this paper, we prove the conjecture for graphs whose complements contain no cycles of length 4.

  13. Constraining the interacting dark energy models from weak gravity conjecture and recent observations

    CERN Document Server

    Chen, Ximing; Pan, Nana; Gong, Yungui

    2010-01-01

    We examine the effectiveness of the weak gravity conjecture in constraining the dark energy by comparing with observations. For general dark energy models with plausible phenomenological interactions between dark sectors, we find that although the weak gravity conjecture can constrain the dark energy, the constraint is looser than that from the observations.

  14. Limits from Weak Gravity Conjecture on Chaplygin-Gas-Type Models

    Institute of Scientific and Technical Information of China (English)

    WU Xing; ZHU Zong-Hong

    2008-01-01

    @@ The weak gravity conjecture is proposed as a criterion to distinguish the landscape from the swampland in string theory. As an application in cosmology of this conjecture, we use it to impose theoretical constraint on parameters of the Chaplygin-gas-type models. Our analysis indicates that the Chaplygin-gas-type models realized in quintessence field are in the swampland.

  15. A NEGATIVE ANSWER TO A CONJECTURE ON SELF-SIMILAR SETS WITH OPEN SET CONDITION

    Institute of Scientific and Technical Information of China (English)

    Jiandong Yin

    2009-01-01

    Zhou and Feng posed a conjecture on self-similar set in 2004. In this paper, a self-similar set is constructed which has a best covering but its natural covering is not a best one. Thus, we indeed give a negative answer to the conjecture.

  16. Noncommutative Versions of the Singer-Wermer Conjecture with Linear Left θ-derivations

    Institute of Scientific and Technical Information of China (English)

    Yong Soo JUNG; Kyoo Hong PARK

    2008-01-01

    The noncommutative Singer-Wermer conjecture states that every linear(possibly unbounded)derivation on a(possibly noncommutative)Banach algebra maps into its Jacobson radical.This conjecture is still an open question for more than thirty years.In this paper we approach this question via linear left θ-derivations.

  17. Modelling of and Conjecturing on a Soccer Ball in a Korean Eighth Grade Mathematics Classroom

    Science.gov (United States)

    Lee, Kyeong-Hwa

    2011-01-01

    The purpose of this article was to describe the task design and implementation of cultural artefacts in a mathematics lesson based on the integration of modelling and conjecturing perspectives. The conceived process of integrating a soccer ball into mathematics lessons via modelling- and conjecturing-based instruction was first detailed. Next, the…

  18. Biologia de Automeris illustris (Walker (Lepidoptera, Saturniidae, Hemileucinae Biology of Automeris illustris (Walker (Lepidoptera, Saturniidae, Hemileucinae

    Directory of Open Access Journals (Sweden)

    Alexandre Specht

    2006-06-01

    Full Text Available Objetivou-se estudar a biologia de Automeris illustris (Walker, 1855, um hemileucíneo polifitófago considerado praga secundária da eucaliptocultura e cujas lagartas podem provocar erucismo. Os parâmetros biológicos foram obtidos em condições controladas de temperatura: 25 ± 1ºC, UR 70 ± 10% e fotofase de 14 horas, com observações diárias. Foram avaliados, em cada fase de desenvolvimento, aspectos morfológicos e etológicos, duração e viabilidade. Para relacionar as plantas hospedeiras foram reunidos dados de material coletado em campo e já referidos em bibliografia. Nas condições de laboratório observou-se que o ciclo de vida necessitou de aproximadamente 121 dias, cujos períodos médios das fases de ovo, lagarta, pré-pupa, pupa e adulta foram de 10,60; 80,56; 3,58; 19,17 e 7,83 dias, respectivamente. As lagartas passaram por seis ínstares e tiveram uma razão média de crescimento de 1,47. Observou-se um alto grau de polifitofagia sendo relacionadas 51 plantas hospedeiras pertencentes a 28 famílias. O potencial biótico foi estimado em 8.719.556 indivíduos ao ano.This work aimed to study the biology of Automeris illustris (Walker, 1855 which is a polyphytophagous, considered secondary pest of eucalypts culture in wich their caterpillars might cause erucism. The biological parameters were obtained in controlled conditions of temperature: 25 ± 1ºC, UR 70 ± 10% and photofase of 14 hours, with daily observations. On each developmental phase, morphological and ethologic aspects, as well as duration and viability, were evaluated. In order to link the host plants to the insect it were added data of collected material on field and referred in the bibliography. Under laboratory conditions it was observed that the life cycle needed of about 121 days whose mean periods of eggs, caterpillars, pre-pupae, pupae and adult phases were 10.60, 80.56, 3.58, 19.17 and 7.83 days, respectively. The caterpillars passed by six instars with

  19. The role of walkers' needs and expectations in supporting maintenance of attendance at walking groups: a longitudinal multi-perspective study of walkers and walk group leaders.

    Directory of Open Access Journals (Sweden)

    Aikaterini Kassavou

    Full Text Available There is good evidence that when people's needs and expectations regarding behaviour change are met, they are satisfied with that change, and maintain those changes. Despite this, there is a dearth of research on needs and expectations of walkers when initially attending walking groups and whether and how these needs and expectations have been satisfied after a period of attendance. Equally, there is an absence of research on how people who lead these groups understand walkers' needs and walk leaders' actions to address them. The present study was aimed at addressing both of these gaps in the research.Two preliminary thematic analyses were conducted on face-to-face interviews with (a eight walkers when they joined walking groups, five of whom were interviewed three months later, and (b eight walk leaders. A multi-perspective analysis building upon these preliminary analyses identified similarities and differences within the themes that emerged from the interviews with walkers and walk leaders.Walkers indicated that their main needs and expectations when joining walking groups were achieving long-term social and health benefits. At the follow up interviews, walkers indicated that satisfaction with meeting similar others within the groups was the main reason for continued attendance. Their main source of dissatisfaction was not feeling integrated in the existing walking groups. Walk leaders often acknowledged the same reasons for walkers joining and maintaining attendance at walking. However, they tended to attribute dissatisfaction and drop out to uncontrollable environmental factors and/or walkers' personalities. Walk leaders reported a lack of efficacy to effectively address walkers' needs.Interventions to increase retention of walkers should train walk leaders with the skills to help them modify the underlying psychological factors affecting walkers' maintenance at walking groups. This should result in greater retention of walkers in walking

  20. Comparative Analysis of Probabilistic Models for Activity Recognition with an Instrumented Walker

    CERN Document Server

    Omar, Farheen; Truszkowski, Jakub; Poupart, Pascal; Tung, James; Caine, Allen

    2012-01-01

    Rollating walkers are popular mobility aids used by older adults to improve balance control. There is a need to automatically recognize the activities performed by walker users to better understand activity patterns, mobility issues and the context in which falls are more likely to happen. We design and compare several techniques to recognize walker related activities. A comprehensive evaluation with control subjects and walker users from a retirement community is presented.

  1. Organ Facts: Kidney / Pancreas

    Science.gov (United States)

    ... Lung Kidney Pancreas Kidney/Pancreas Liver Intestine Kidney/Pancreas Facts The kidneys are a pair of reddish- ... the chemical (electrolyte) composition of the blood. The pancreas is a five to six inch gland located ...

  2. HRSA Data Fact Sheets

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Health Resources and Services Administration (HRSA) Data Fact Sheets provide summary data about HRSA’s activities in each Congressional District, County, State,...

  3. Alcohol Facts and Statistics

    Science.gov (United States)

    ... Standard Drink? Drinking Levels Defined Alcohol Facts and Statistics Print version Alcohol Use in the United States: ... 1245, 2004. PMID: 15010446 11 National Center for Statistics and Analysis. 2014 Crash Data Key Findings (Traffic ...

  4. Key Facts about Tularemia

    Science.gov (United States)

    ... Specific Hazards Bioterrorism A-Z Anthrax (Bacillus anthracis) Arenaviruses Treatment & Infection Control Specimen Submission & Lab Testing Education & ... hemorrhagic fevers (filoviruses [e.g., Ebola, Marburg] and arenaviruses [e.g., Lassa, Machupo]) Yersinia pestis (plague) Fact ...

  5. Facts about Botulism

    Science.gov (United States)

    ... Specific Hazards Bioterrorism A-Z Anthrax (Bacillus anthracis) Arenaviruses Treatment & Infection Control Specimen Submission & Lab Testing Education & ... hemorrhagic fevers (filoviruses [e.g., Ebola, Marburg] and arenaviruses [e.g., Lassa, Machupo]) Yersinia pestis (plague) Fact ...

  6. Facts about Benzene

    Science.gov (United States)

    ... Specific Hazards Bioterrorism A-Z Anthrax (Bacillus anthracis) Arenaviruses Treatment & Infection Control Specimen Submission & Lab Testing Education & ... hemorrhagic fevers (filoviruses [e.g., Ebola, Marburg] and arenaviruses [e.g., Lassa, Machupo]) Yersinia pestis (plague) Fact ...

  7. CMS Fast Facts

    Data.gov (United States)

    U.S. Department of Health & Human Services — CMS has developed a new quick reference statistical summary on annual CMS program and financial data. CMS Fast Facts includes summary information on total program...

  8. Drug Facts: Anabolic Steroids

    Science.gov (United States)

    ... ctrl+c to copy Additional Drug Facts Other Articles of Interest NIDA Notes Prevention Program Reduces Substance Use By Participants' Friends Elevated Rates of Drug Abuse Continue for Second Year Nora's ...

  9. Pharmacogenomics Fact Sheet

    Science.gov (United States)

    ... incorporate genomic results into medical care. Other NIGMS Fact Sheets Related Links Up to top This page last reviewed on September 28, 2017 Social Media Links Bookmark & Share Free Subscriptions Twitter Facebook ...

  10. Facts about Birth Defects

    Science.gov (United States)

    ... Button Information For… Media Policy Makers Facts about Birth Defects Language: English (US) Español (Spanish) Recommend ... having a baby born without a birth defect. Birth Defects Are Common Every 4 ½ minutes, a ...

  11. Facts about Thalassemia

    Science.gov (United States)

    ... CDC’s Work Related Information UDC System Facts About Thalassemia Recommend on Facebook Tweet Share Compartir Did You ... to death. What are the different types of thalassemia? When we talk about different “types” of thalassemia, ...

  12. Postpartum Depression Facts

    Science.gov (United States)

    ... Where can I find more information? Share Postpartum Depression Facts Download PDF Download ePub Download Mobi Order ... for herself or her family. What is postpartum depression? Postpartum depression is a mood disorder that can ...

  13. Childhood Obesity Facts

    Science.gov (United States)

    ... Breastfeeding Micronutrient Malnutrition State and Local Programs Childhood Obesity Facts Recommend on Facebook Tweet Share Compartir On ... Children (WIC) Program, 2000–2014 Prevalence of Childhood Obesity in the United States, 2011-2014 Childhood obesity ...

  14. Respirator Fact Sheet

    Science.gov (United States)

    ... have expiration dates that should be checked before purchase. Also, over time your mask can get old ... Respirator Fact Sheet [PDF - 706 KB] Follow NIOSH Facebook Flickr Pinterest Twitter YouTube NIOSH Homepage NIOSH A- ...

  15. SEER Cancer Stat Facts

    Science.gov (United States)

    Cancer Statistical Fact Sheets are summaries of common cancer types developed to provide an overview of frequently-requested cancer statistics including incidence, mortality, survival, stage, prevalence, and lifetime risk.

  16. Facts You Should Know

    Science.gov (United States)

    ... military veterans, particularly those deployed during the Gulf War, are approximately twice as likely to develop ALS. ... management interventions, riluzole and possibly other compounds and drugs under investigation. Facts You Should Know ALS is ...

  17. Facts about Physical Activity

    Science.gov (United States)

    ... Nutrition Physical Activity Overweight & Obesity Healthy Weight Breastfeeding Micronutrient Malnutrition State and Local Programs Facts about Physical ... Nutrition Physical Activity Overweight & Obesity Healthy Weight Breastfeeding Micronutrient Malnutrition State and Local Programs File Formats Help: ...

  18. [Suicide, a social fact].

    Science.gov (United States)

    Baudelot, Christian

    2017-04-01

    Treating suicide as a social fact means disregarding its individual and dramatic dimensions. Sociologists do not reason on the basis of specific cases but by studying the variations, in space and time, of suicide rates. Their contribution relates essentially to a renewed perspective on society: suicide is in fact a very accurate indicator of the intensity and quality of the bonds which unite or isolate individuals in a society. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  19. Segmentation of stochastic images with a stochastic random walker method.

    Science.gov (United States)

    Pätz, Torben; Preusser, Tobias

    2012-05-01

    We present an extension of the random walker segmentation to images with uncertain gray values. Such gray-value uncertainty may result from noise or other imaging artifacts or more general from measurement errors in the image acquisition process. The purpose is to quantify the influence of the gray-value uncertainty onto the result when using random walker segmentation. In random walker segmentation, a weighted graph is built from the image, where the edge weights depend on the image gradient between the pixels. For given seed regions, the probability is evaluated for a random walk on this graph starting at a pixel to end in one of the seed regions. Here, we extend this method to images with uncertain gray values. To this end, we consider the pixel values to be random variables (RVs), thus introducing the notion of stochastic images. We end up with stochastic weights for the graph in random walker segmentation and a stochastic partial differential equation (PDE) that has to be solved. We discretize the RVs and the stochastic PDE by the method of generalized polynomial chaos, combining the recent developments in numerical methods for the discretization of stochastic PDEs and an interactive segmentation algorithm. The resulting algorithm allows for the detection of regions where the segmentation result is highly influenced by the uncertain pixel values. Thus, it gives a reliability estimate for the resulting segmentation, and it furthermore allows determining the probability density function of the segmented object volume.

  20. Construction of calibration pads facility, Walker Field, Grand Junction, Colorado

    Energy Technology Data Exchange (ETDEWEB)

    Ward, D.L.

    1978-08-01

    A gamma-ray spectrometer facility was completed at Walker Field Airport, Grand Junction, Colorado, in November 1976. This report describes spectrometers and their calibration, the construction of the spectrometer facility, the radioelement concentrations, procedures for using the facilites, and environmental considerations. (LK)

  1. 75 FR 35265 - Safety Standard for Infant Walkers: Final Rule

    Science.gov (United States)

    2010-06-21

    .../jumping. Occupant retention--intended to prevent entrapment by setting requirements for leg openings. The... force by means of a pulley, rope, and a falling 8-pound weight on a hardwood floor surface. The walker... components are not specified. Variability in the type and size of the pulley, rope type, test table flexure...

  2. Bobble-Head Doll and Dandy-Walker Syndromes

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2007-10-01

    Full Text Available A female infant with macrocephaly (head circumference >95th%, hydrocephalus, and Dandy-Walker syndrome, who developed horizontal head movements of the 'no-no' type at 1 year of age, is reported from Federal University of Minas Gerais, and other centers in Brazil.

  3. f-symbols in Robertson-Walker space-times

    CERN Document Server

    Popa, F C; Popa, Florian Catalin; Tintareanu-Mircea, Ovidiu

    2004-01-01

    In a Robertson-Walker space-time a spinning particle model is investigated and we show that in a stationary case, there exists a class of new structures called f-symbols which can generate reducible Killing tensors and supersymmetry algebras.

  4. Alice Walker's Womanism Colored in The Color Purple

    Institute of Scientific and Technical Information of China (English)

    蒋慧慧

    2009-01-01

    In her famous novel The Color Purple,Alice Walker's womanism is colored by four kinds of conseiousness-female consciousness,racial consciousness,root-seeking consciousness,and universal consciousness.It is owing to the womanism that the heroine celie grown from an abused woman to an independent selfhood.

  5. A new species of Culcua Walker (Diptera: Stratiomyidae) from Vietnam

    Science.gov (United States)

    A new species of Culcua Walker (Diptera: Stratiomyidae), C. lingafelteri Woodley, new species, is described from northern Vietnam. It is diagnosed relative to other species using the recent revision of the genus by Rozkošný and Kozánek (2007). This is the first species of Culcua reported from Viet...

  6. Selling Out Mothers and Babies by Marsha Walker

    OpenAIRE

    Sandra M., Gossler

    2003-01-01

    The monitoring project reported in Marsha Walker's book, Selling Out Mothers and Babies, offers a qualitative assessment of formula companies' unethical marketing practices in the United States. The book presents extensive documentation on the questionable strategies of formula companies and how they avoid and circumvent recommendations of the International Code of Marketing of Breast Milk Substitutes.

  7. Behavior of Friedmann-Lemaître-Robertson-Walker Singularities

    Science.gov (United States)

    Fernández-Jambrina, L.

    2016-08-01

    In Stoica (Int. J. Theor. Phys. 55, 71-80, 2016) a regularization procedure is suggested for regularizing Big Bang singularities in Friedmann-Lemaître-Robertson-Walker (FLRW) spacetimes. We argue that this procedure is only appliable to one case of Big Bang singularities and does not affect other types of singularities.

  8. Twisted gauge theories in 3D Walker-Wang models

    CERN Document Server

    Wang, Zitao

    2016-01-01

    Three dimensional gauge theories with a discrete gauge group can emerge from spin models as a gapped topological phase with fractional point excitations (gauge charge) and loop excitations (gauge flux). It is known that 3D gauge theories can be "twisted", in the sense that the gauge flux loops can have nontrivial braiding statistics among themselves and such twisted gauge theories are realized in models discovered by Dijkgraaf and Witten. A different framework to systematically construct three dimensional topological phases was proposed by Walker and Wang and a series of examples have been studied. Can the Walker Wang construction be used to realize the topological order in twisted gauge theories? This is not immediately clear because the Walker-Wang construction is based on a loop condensation picture while the Dijkgraaf-Witten theory is based on a membrane condensation picture. In this paper, we show that the answer to this question is Yes, by presenting an explicit construction of the Walker Wang models wh...

  9. A methodology to calibrate pedestrian walker models using multiple objectives

    NARCIS (Netherlands)

    Campanella, M.C.; Daamen, W.; Hoogendoorn, S.P.

    2012-01-01

    The application of walker models to simulate real situations require accuracy in several traffic situations. One strategy to obtain a generic model is to calibrate the parameters in several situations using multiple-objective functions in the optimization process. In this paper, we propose a general

  10. Bathymetry of Walker Lake, West-Central Nevada

    Science.gov (United States)

    Lopes, Thomas J.; Smith, J. LaRue

    2007-01-01

    Walker Lake lies within a topographically closed basin in west-central Nevada and is the terminus of the Walker River. Much of the streamflow in the Walker River is diverted for irrigation, which has contributed to a decline in lake-surface altitude of about 150 feet and an increase in dissolved solids from 2,500 to 16,000 milligrams per liter in Walker Lake since 1882. The increase in salinity threatens the fresh-water ecosystem and survival of the Lahontan cutthroat trout, a species listed as threatened under the Endangered Species Act. Accurately determining the bathymetry and relations between lake-surface altitude, surface area, and storage volume are part of a study to improve the water budget for Walker Lake. This report describes the updated bathymetry of Walker Lake, a comparison of results from this study and a study by Rush in 1970, and an estimate of the 1882 lake-surface altitude. Bathymetry was measured using a single-beam echosounder coupled to a differentially-corrected global positioning system. Lake depth was subtracted from the lake-surface altitude to calculate the altitude of the lake bottom. A Lidar (light detection and ranging) survey and high resolution aerial imagery were used to create digital elevation models around Walker Lake. The altitude of the lake bottom and digital elevation models were merged together to create a single map showing land-surface altitude contours delineating areas that are currently or that were submerged by Walker Lake. Surface area and storage volume for lake-surface altitudes of 3,851.5-4,120 feet were calculated with 3-D surface-analysis software. Walker Lake is oval shaped with a north-south trending long axis. On June 28, 2005, the lake-surface altitude was 3,935.6 feet, maximum depth was 86.3 feet, and the surface area was 32,190 acres. The minimum altitude of the lake bottom from discrete point depths is 3,849.3 feet near the center of Walker Lake. The lake bottom is remarkably smooth except for mounds near

  11. Philip Glass, Scott Walker ja Sigur Ros! / Immo Mihkelson

    Index Scriptorium Estoniae

    Mihkelson, Immo, 1959-

    2007-01-01

    Pimedate Ööde 11. filmifestivali muusikafilme - Austraalia "Glass: Philipi portree 12 osas" (rež. Scott Hicks), Islandi "Sigur Ros kodus" (rež. Dean DeBois), Suurbritannia "Scott Walker: 30 Century Man" (rež. Stephen Kijak)

  12. Finding the Right Formula: Edwin H. Walker Jr

    Science.gov (United States)

    Keels, Crystal L.

    2005-01-01

    Edwin H. Walker Jr earned his doctorate in chemistry at age 27 and has barely looked back. With 13 publications under his belt before coming out of graduate school, he has also given more than 20 poster presentations in national venues, most recently at the American Chemical Society. He can also include securing a half-million-dollar National…

  13. Larval description of Copitarsia incommoda (Walker) (Lepidoptera: Noctuidae)

    Science.gov (United States)

    The last-instar larva of Copitarsia incommoda (Walker) is described for the first time. Specimens in this study were reared from quinoa (Chenopodium quinoa Willd., Chenopodiaceae), Bolivia, La Paz, 4 km S Viacha, Quipaquipani, 3880 m. The larva of Copitarsia incommoda is compared with larvae of Copi...

  14. Philip Glass, Scott Walker ja Sigur Ros! / Immo Mihkelson

    Index Scriptorium Estoniae

    Mihkelson, Immo, 1959-

    2007-01-01

    Pimedate Ööde 11. filmifestivali muusikafilme - Austraalia "Glass: Philipi portree 12 osas" (rež. Scott Hicks), Islandi "Sigur Ros kodus" (rež. Dean DeBois), Suurbritannia "Scott Walker: 30 Century Man" (rež. Stephen Kijak)

  15. 75 FR 24753 - The Walker Auto Group, Inc., Miamisburg, OH; Notice of Negative Determination Regarding...

    Science.gov (United States)

    2010-05-05

    ... Employment and Training Administration The Walker Auto Group, Inc., Miamisburg, OH; Notice of Negative... TAA petition filed on behalf of workers at The Walker Auto Group, Inc., Miamisburg, Ohio, was based on... Walker Auto Group, Inc., Miamisburg, Ohio, supplies a service (sales and service of Pontiac automobiles...

  16. The Weak Gravity Conjecture and Effective Field Theory

    CERN Document Server

    Saraswat, Prashant

    2016-01-01

    The Weak Gravity Conjecture (WGC) is a proposed constraint on theories with gauge fields and gravity, requiring the existence of light charged particles and/or imposing an upper bound on the field theory cutoff $\\Lambda$. If taken as a consistency requirement for effective field theories (EFTs), it rules out possibilities for model-building including some models of inflation. I demonstrate simple models which satisfy all forms of the WGC, but which through Higgsing of the original gauge fields produce low-energy EFTs with gauge forces that badly violate the WGC. These models illustrate specific loopholes in arguments that motivate the WGC from a bottom-up perspective; for example the arguments based on magnetic monopoles are evaded when the magnetic confinement that occurs in a Higgs phase is accounted for. This indicates that the WGC should not be taken as a veto on EFTs, even if it turns out to be a robust property of UV quantum gravity theories. However, if the latter is true then parametric violation of t...

  17. Test Driven Development: Advancing Knowledge by Conjecture and Confirmation

    Directory of Open Access Journals (Sweden)

    Manfred Lange

    2011-12-01

    Full Text Available Test Driven Development (TDD is a critical agile software development practice that supports innovation in short development cycles. However, TDD is one of the most challenging agile practices to adopt because it requires changes to work practices and skill sets. It is therefore important to gain an understanding of TDD through the experiences of those who have successfully adopted this practice. We collaborated with an agile team to provide this experience report on their adoption of TDD, using observations and interviews within the product development environment. This article highlights a number of practices that underlie successful development with TDD. To provide a theoretical perspective that can help to explain how TDD supports a positive philosophy of software development, we have revised Northover et al.’s conceptual framework, which is based on a four stage model of agile development, to reinterpret Popper’s theory of conjecture and falsification in the context of agile testing strategies. As a result of our findings, we propose an analytical model for TDD in agile software development which provides a theoretical basis for further investigations into the role of TDD and related practices.

  18. Solution of the propeller conjecture in $\\R^3$

    CERN Document Server

    Heilman, Steven; Naor, Assaf

    2011-01-01

    It is shown that every measurable partition ${A_1,..., A_k}$ of $\\R^3$ satisfies \\sum_{i=1}^k|\\int_{A_i} xe^{-\\frac12|x|_2^2}dx|_2^2\\le 9\\pi^2. Let ${P_1,P_2,P_3}$ be the partition of $\\R^2$ into $120^\\circ$ sectors centered at the origin. The bound is sharp, with equality holding if $A_i=P_i\\times \\R$ for $i\\in {1,2,3}$ and $A_i=\\emptyset$ for $i\\in \\{4,...,k}$ (up to measure zero corrections, orthogonal transformations and renumbering of the sets $\\{A_1,...,A_k\\}$). This settles positively the 3-dimensional Propeller Conjecture of Khot and Naor (FOCS 2008). The proof of reduces the problem to a finite set of numerical inequalities which are then verified with full rigor in a computer-assisted fashion. The main consequence (and motivation) of \\eqref{eq:abs} is complexity-theoretic: the Unique Games hardness threshold of the Kernel Clustering problem with 4 \\times 4 centered and spherical hypothesis matrix equals $\\frac{2\\pi}{3}$.

  19. Fact Finding Nuclear Energy; Fact Finding Kernenergie

    Energy Technology Data Exchange (ETDEWEB)

    Scheepers, M.J.J.; Seebregts, A.J.; Lako, P. [ECN-Beleidsstudies, Petten (Netherlands); Blom, F.J.; Van Gemert, F. [Sociaal-Economische Raad SER, Den Haag (Netherlands)

    2007-09-15

    Facts and figures on nuclear energy are presented to enable a discussion on the role of nuclear power in the transition to a sustainable energy supply for the Netherlands. The following issues are presented: Nuclear technology, safety and security (including non-proliferation and protection against terrorism); Environmental aspects (including greenhouse gas emissions of the nuclear energy lifecycle); Nuclear power and the power market (including impact of nuclear power on electricity market prices); Economic aspects (including costs of nuclear power and external costs and benefits); Policy issues (including sustainable development); Social acceptance of nuclear energy; Knowledge infrastructure for nuclear energy in the Netherlands; and Nuclear power in long term energy scenarios for the Netherlands and Europe. Using two long-term energy scenarios the report also presents a social impact analysis of an increasing share of nuclear power in the Dutch electricity supply. [Dutch] In dit onderzoek zijn feiten en gegevens over kernenergie verzameld op basis van bestaande inzichten en een veelheid aan literatuur (fact finding). Voor technologische expertise heeft ECN zich laten bijstaan door de Nucleair Research and consultancy Group (NRG). Op basis van de fact-finding studie bereidt de SER een advies voor over de rol van kernenergie in de toekomstige nationale elektriciteitsproductie. In de eerste acht hoofdstukken worden feiten en gegevens gepresenteerd over verschillende onderwerpen die bij kernenergie van belang zijn. In Hoofdstuk 2 wordt de kernenergietechnologie beschreven, inclusiefde veiligheid van kernenergie besproken, omdat die nauw met de technologie samenhangt. Hierbij gaat het om de technische veiligheid van de installaties, maar ook om beveiliging tegen misbruik van technologie en nucleair materiaal, waaronder beveiliging tegen terrorisme. De milieuaspecten door radioactiviteit en door emissies van kooldioxide die met het gebruik van kernenergie samenhangen

  20. An additive combinatorics approach to the log-rank conjecture in communication complexity

    CERN Document Server

    Ben-Sasson, Eli; Zewi, Noga

    2011-01-01

    For a $\\{0,1\\}$-valued matrix $M$ let $\\rm{CC}(M)$ denote the deterministic communication complexity of the boolean function associated with $M$. The log-rank conjecture of Lov\\'{a}sz and Saks [FOCS 1988] states that $\\rm{CC}(M) \\leq \\log^c(\\rm{rank}(M))$ for some absolute constant $c$ where $\\rm{rank}(M)$ denotes the rank of $M$ over the field of real numbers. We show that $\\rm{CC}(M)\\leq c \\cdot \\rm{rank}(M)/\\log \\rm{rank}(M)$ for some absolute constant $c$, assuming a well-known conjecture from additive combinatorics known as the Polynomial Freiman-Ruzsa (PFR) conjecture. Our proof is based on the study of the "approximate duality conjecture" which was recently suggested by Ben-Sasson and Zewi [STOC 2011] and studied there in connection to the PFR conjecture. First we improve the bounds on approximate duality assuming the PFR conjecture. Then we use the approximate duality conjecture (with improved bounds) to get the aforementioned upper bound on the communication complexity of low-rank martices, where thi...

  1. Analytical study of the conjecture rule for the combination of multipole effects in LHC

    CERN Document Server

    Guignard, Gilbert

    1997-01-01

    This paper summarizes the analytical investigation done on the conjecture law found by tracking for the effect on the dynamic aperture of the combination of two multipoles of various order. A one-dimensional model leading to an integrable system has been used to find closed formulae for the dynamic aperture associated with a fully distributed multipole. The combination has then been studied and the resulting expression compared with the assumed conjecture law. For integrated multipoles small with respect to the focusing strength, the conjecture appears to hold, though with an exponent different from the one expected by crude reasoning.

  2. Weak Gravity Conjecture and Holographic Dark Energy Model with Interaction and Spatial Curvature

    Institute of Scientific and Technical Information of China (English)

    SUN Cheng-Yi

    2011-01-01

    In the paper, we apply the weak gravity conjecture to the holographic quintessence model of dark energy.Three different holographic dark energy models are considered: without the interaction in the non-flat universe; with interaction in the flat universe; with interaction in the non-flat universe. We find that only in the models with the spatial curvature and interaction term proportional to the energy density of matter, it is possible for the weak gravity conjecture to be satisfied. And it seems that the weak gravity conjecture favors an open universe and the decaying of matter into dark energy.

  3. The Shapiro Conjecture Prompt or Delayed Collapse in the head-on collision of neutron stars?

    CERN Document Server

    Miller, M; Tobias, M; Miller, Mark; Suen, Wai-Mo; Tobias, Malcolm

    1999-01-01

    We study the question of prompt vs. delayed collapse in the head-on collision of two neutron stars. We show that the prompt formation of a black hole is possible, contrary to a conjecture of Shapiro which claims that collapse is delayed until after neutrino cooling. We discuss the insight provided by Shapiro's conjecture and its limitation. An understanding of the limitation of the conjecture is provided in terms of the many time scales involved in the problem. General relativistic simulations in the Einstein theory with the full set of Einstein equations coupled to the general relativistic hydrodynamic equations are carried out in our study.

  4. On the non-commutative Local Main Conjecture for elliptic curves with complex multiplication

    CERN Document Server

    Venjakob, Otmar

    2012-01-01

    This paper is a natural continuation of the joint work [6] on non-commutative Main Conjectures for CM elliptic curves: now we concentrate on the local Main Conjecture or more precisely on the epsilon-isomorphism conjecture by Fukaya and Kato in [20]. Our results rely heavily on Kato's unpublished proof of (commutative) epsilon-isomorphisms for one dimensional representations of G_{Q_p} in [24]. For the convenience of the reader we give a slight modification or rather reformulation of it in the language of [20] and extend it to the (slightly non-commutative) semi-global setting.

  5. Facts in artifacts

    Directory of Open Access Journals (Sweden)

    P R Bindhu

    2013-01-01

    Full Text Available Examination of microscopic sections of animal tissues reveals facts which are not always related to its normal histology or pathology. Processing of tissue specimens consists of lengthy procedures from the stage of surgical removal to the stained and mounted microscopic sections. Defects are common in tissue sections as a result of faulty procedures. These defects are referred to as artifacts. They lead to misinterpretation of histopathological diagnosis but at times they throw limelight into diagnosis. This paper attempts to put together all the facts regarding the various artifacts that are encountered in histopathology.

  6. Energy Facts, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1993-10-29

    Energy Facts, organized by energy source, is a compilation of energy data providing a reference to a broad range of domestic and international energy data, for the general public as well as the technical community. This report is designed especially for the business person, government worker, or student who needs a quick reference to major facts about energy. Each table of statistics appears on the opposite page from a corresponding graphic. The graphic has a point of interest rather than a title across the top.

  7. Entrevista al profesor D. Michael Walker. - Interview with Professor D. Michael Walker.

    Directory of Open Access Journals (Sweden)

    Caravaca Guerrero, Consuelo Isabel

    2014-12-01

    Full Text Available Entrevistar a un investigador de la talla de D. Michael Walker supone hablar de un investigador reconocido a nivel nacional e internacional, uno de los mayores expertos en evolución humana de nuestros días. Nació en Colchester (Inglaterra en 1941 y tiene doble nacionalidad: británica y australiana. Actualmente es profesor emérito de la Universidad de Murcia en el Departamento de Zoología y Antropología Física de la Facultad de Biología. Pero su currículum no acaba aquí, Michael realizó tres carreras, Fisiología Animal, Medicina, y Arqueología Prehistórica, en la Universidad de Oxford. Es Doctor por esta universidad, gracias a su tesis leída sobre Paleoantropología y Prehistoria de las cuencas de los ríos Segura y Vinalopó. Nuestro entrevistado, también fue elegido Académico (Fellow –F.S.A.- en 1988 de la Society of Antiquaries of Londono SAL. Fundada en 1707, la SAL es la equivalente británica de la española Real Academia de la Historia. Es Fellow también del Real Instituto Antropológico de la Gran Bretaña (Royal Anthropological Institute of Great Britain y socio emérito de la Asociación Americana de Antropólogos Físicos (American Association of Physical Anthropologists.

  8. Reduced incidence of cardiac arrhythmias in walkers and runners.

    Directory of Open Access Journals (Sweden)

    Paul T Williams

    Full Text Available PURPOSE: Walking is purported to reduce the risk of atrial fibrillation by 48%, whereas jogging is purported to increase its risk by 53%, suggesting a strong anti-arrhythmic benefit of walking over running. The purpose of these analyses is to compare incident self-reported physician-diagnosed cardiac arrhythmia to baseline energy expenditure (metabolic equivalent hours per day, METhr/d from walking, running and other exercise. METHODS: Proportional hazards analysis of 14,734 walkers and 32,073 runners. RESULTS: There were 1,060 incident cardiac arrhythmias (412 walkers, 648 runners during 6.2 years of follow-up. The risk for incident cardiac arrhythmias declined 4.4% per baseline METhr/d walked by the walkers, or running in the runners (P = 0.0001. Specifically, the risk declined 14.2% (hazard ratio: 0.858 for 1.8 to 3.6 METhr/d, 26.5% for 3.6 to 5.4 METhr/d, and 31.7% for ≥5.4 METhr/d, relative to <1.8 METhr/d. The risk reduction per METhr/d was significantly greater for walking than running (P<0.01, but only because walkers were at 34% greater risk than runners who fell below contemporary physical activity guideline recommendations; otherwise the walkers and runners had similar risks for cardiac arrhythmias. Cardiac arrhythmias were unrelated to walking and running intensity, and unrelated to marathon participation and performance. CONCLUSIONS: The risk for cardiac arrhythmias was similar in walkers and runners who expended comparable METhr/d during structured exercise. We found no significant risk increase for self-reported cardiac arrhythmias associated with running distance, exercise intensity, or marathon participation. Rhythm abnormalities were based on self-report, precluding definitive categorization of the nature of the rhythm disturbance. However, even if the runners' arrhythmias include sinus bradycardia due to running itself, there was no increase in arrhythmias with greater running distance.

  9. Revalidation of Ceresa terminalis walker and its placement in Stictocephala Stål (Hemiptera, Membracidae Revalidação de Ceresa terminalis walker e sua alocação em Stictocephala Stål (Hemiptera, Membracidae

    Directory of Open Access Journals (Sweden)

    Gabriel S. de Andrade

    2005-12-01

    Full Text Available Ceresa terminalis Walker, 1851 is reinstated and transferred to Stictocephala Stål, 1869: Stictocephala terminalis (Walker, 1851 sp. rev., comb. nov.Ceresa terminalis Walker, 1851 é revalidada e transferida para Stictocephala Stål, 1869: Stictocephala terminalis (Walker, 1851 sp. rev., comb. nov.

  10. Facts about Vitamin K

    Science.gov (United States)

    Facts about Vitamin K 1 R. Elaine Turner and Wendy J. Dahl 2 FCS8666 Figure 1. Vitamin K is mostly found in vegetables, especially green ... ColognePhotos/iStock/Thinkstock, © ColognePhotos Why do we need vitamin K? Vitamin K is one of the fat- ...

  11. NASA Facts, Voyager.

    Science.gov (United States)

    National Aeronautics and Space Administration, Washington, DC. Educational Programs Div.

    This document is one of a series of publications of the National Aeronautics and Space Administration (NASA) on facts about the exploration of Jupiter and Saturn. This NASA mission consists of two unmanned Voyager spacecrafts launched in August and September of 1977, and due to arrive at Jupiter in 1979. An account of the scientific equipment…

  12. Burns Fact Sheet

    Science.gov (United States)

    ... and Answers page . Share Print E-mail House Image Highlight Header Learn More Highlight Body Other NIGMS Fact Sheets Related Links Up to top This page last reviewed on April 06, 2016 Social Media Links Bookmark & Share Free Subscriptions Twitter Facebook YouTube ...

  13. Nuclear fact book

    Energy Technology Data Exchange (ETDEWEB)

    Hill, O. F.; Platt, A. M.; Robinson, J. V. [comps

    1983-05-01

    This reference provides significant highlights and summary facts in the following areas: general energy; nuclear energy; nuclear fuel cycle; uranium supply and enrichment; nuclear reactors; spent fuel and advanced repacking concepts; reprocessing; high-level waste; gaseous waste; transuranic waste; low-level waste; remedial action; transportation; disposal; radiation information; environment; legislation; socio-political aspects; conversion factors; and a glossary. (GHT)

  14. Facts about Down Syndrome

    Science.gov (United States)

    ... label> Information For… Media Policy Makers Facts about Down Syndrome Language: English (US) Español (Spanish) Recommend on ... children with Down syndrome. View charts » What is Down Syndrome? Down syndrome is a condition in which a ...

  15. Trauma Facts for Educators

    Science.gov (United States)

    National Child Traumatic Stress Network, 2008

    2008-01-01

    This paper offers facts which can help educators deal with children undergoing trauma. These include: (1) One out of every 4 children attending school has been exposed to a traumatic event that can affect learning and/or behavior; (2) Trauma can impact school performance; (3) Trauma can impair learning; (4) Traumatized children may experience…

  16. Facts about Type 2

    Medline Plus

    Full Text Available ... Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor Tools To Know Your Risk Alert Day Diabetes Basics Home Symptoms Diagnosis America's Diabetes Challenge Type 1 Type 2 Facts About Type 2 Enroll in ...

  17. Ethanol Basics (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2015-01-01

    Ethanol is a widely-used, domestically-produced renewable fuel made from corn and other plant materials. More than 96% of gasoline sold in the United States contains ethanol. Learn more about this alternative fuel in the Ethanol Basics Fact Sheet, produced by the U.S. Department of Energy's Clean Cities program.

  18. Facts about Antibiotic Resistance

    Science.gov (United States)

    ... Cost References Español: Datos breves Facts about Antibiotic Resistance Antibiotic resistance is one of the world’s most pressing public ... antibiotic use is a key strategy to control antibiotic resistance. Antibiotic resistance in children and older adults are ...

  19. Facts about Type 2

    Medline Plus

    Full Text Available ... Books for Practitioners Professional Membership Please Join Us in the Fight for a Cure Your tax-deductible ... Articles from Diabetes Forecast® magazine: lp-type-2, In this section Diabetes Basics Type 2 Facts About ...

  20. NASA Facts, Solar Cells.

    Science.gov (United States)

    National Aeronautics and Space Administration, Washington, DC.

    The design and function of solar cells as a source of electrical power for unmanned space vehicles is described in this pamphlet written for high school physical science students. The pamphlet is one of the NASA Facts Science Series (each of which consists of four pages) and is designed to fit in the standard size three-ring notebook. Review…

  1. Facts about Vitamin C

    Science.gov (United States)

    Facts About Vitamin C 1 Linda B. Bobroff and Isabel Valentín-Oquendo 2 FCS8702 Why do we need vitamin C? Vitamin C, also known as ascorbic acid, has a ... maintain healthy body tissues and the immune system. Vitamin C also helps the body absorb iron from ...

  2. Facts about Type 2

    Medline Plus

    Full Text Available ... Day Diabetes Basics Home Symptoms Diagnosis America's Diabetes Challenge Type 1 Type 2 Facts About Type 2 ... zone with Tough Mudder! Learn More: Take Ryan’s Challenge - 2017-03-d2sd.html Learn More Take Ryan’s ...

  3. Facts about Type 2

    Medline Plus

    Full Text Available ... org > Diabetes Basics > Type 2 Share: Print Page Text Size: A A A Listen En Español Facts ... 2 Recently Diagnosed Treatment and Care Blood Glucose Control Complications Medication Doctors, Nurses & More Enroll ... Cost of Diabetes Advocate Toolkit Call to Congress Research & ...

  4. Pseudomonas - Fact Sheet

    OpenAIRE

    Public Health Agency

    2012-01-01

    Fact sheet on Pseudomonas, including:What is Pseudomonas?What infections does it cause?Who is susceptible to pseudomonas infection?How will I know if I have pseudomonas infection?How can Pseudomonas be prevented from spreading?How can I protect myself from Pseudomonas?How is Pseudomonas infection treated?

  5. Facts about Type 2

    Medline Plus

    Full Text Available ... Alert Day Diabetes Basics Home Symptoms Diagnosis America's Diabetes Challenge Type 1 Type 2 Facts About Type 2 Enroll in ... Where Do I Begin With Type2? Living With Type 1 Diabetes Enroll in the Living WIth Type 2 Diabetes ...

  6. Diet myths and facts

    Science.gov (United States)

    ... sure to check the serving size too. MYTH? Skipping breakfast makes you gain weight. FACT: Eating a healthy breakfast can help you manage your hunger later in the day and help ... that skipping the morning meal leads directly to weight gain. ...

  7. Proof of a Null Penrose Conjecture using a new Quasi-local Mass

    CERN Document Server

    Roesch, Henri

    2016-01-01

    We define an explicit quasi-local mass functional which is non-decreasing along all foliations (satisfying a convexity assumption) of null cones. We use this new functional to prove the null Penrose conjecture under fairly generic conditions.

  8. A counterexample to Beck's conjecture on the discrepancy of three permutations

    CERN Document Server

    Newman, Alantha

    2011-01-01

    Given three permutations on the integers 1 through n, consider the set system consisting of each interval in each of the three permutations. Jozsef Beck conjectured (c. 1987) that the discrepancy of this set system is O(1). We give a counterexample to this conjecture: for any positive integer n = 3^k, we exhibit three permutations whose corresponding set system has discrepancy Omega(log(n)). Our counterexample is based on a simple recursive construction, and our proof of the discrepancy lower bound is by induction. This example also disproves a generalization of Beck's conjecture due to Spencer, Srinivasan and Tetali, who conjectured that a set system corresponding to l permutations has discrepancy O(sqrt(l)).

  9. Brief Comments on "The Shapiro Conjecture, Prompt or Delayed Collapse ?" by Miller, Suen and Tobias

    CERN Document Server

    Shapiro, S L

    1999-01-01

    Recent numerical simulations address a conjecture by Shapiro that when two neutron stars collide head-on from rest at infinity, sufficient thermal pressure may be generated to support the hot remnant in quasi-static equilibrium against collapse prior to neutrino cooling. The conjecture is meant to apply even when the total remnant mass exceeds the maximum mass of a cold neutron star. One set of simulations seems to corroborate the conjecture, while another, involving higher mass progenitors each very close to the maximum mass, does not. In both cases the total mass of the remnant exceeds the maximum mass. We point out numerical subtleties in performing such simulations when the progenitors are near the maximum mass; they can explain why the simulations might have difficulty assessing the conjecture in such high-mass cases.

  10. Conjectures on the normal covering number of finite symmetric and alternating groups

    Directory of Open Access Journals (Sweden)

    Daniela Bubboloni

    2014-06-01

    Full Text Available Let gamma(Sn be the minimum number of proper subgroups Hi, i = 1,...,ell, of the symmetric group Sn such that each element in Sn lies in some conjugate of one of the Hi. In this paper we conjecture that gamma(Sn =(n/2(1-1/p_1 (1-1/p_2 + 2, where p1, p2 are the two smallest primes in the factorization of n and n is neither a prime power nor a product of two primes. Support for the conjecture is given by a previous result for the case where n has at most two distinct prime divisors. We give further evidence by confirming the conjecture for certain integers of the form n = 15q, for an infinite set of primes q, and by reporting on a Magma computation. We make a similar conjecture for gamma(An, when n is even, and provide a similar amount of evidence.

  11. Tiny graviton matrix theory: DLCQ of IIB plane-wave string theory, a conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Sheikh-Jabbari, Mohammad M. [Department of Physics, Stanford University, 382 via Pueblo Mall, Stanford CA 94305-4060 (United States)]. E-mail: jabbari@itp.stanford.edu

    2004-09-01

    We conjecture that the discrete light-cone quantization (DLCQ) of strings on the maximally supersymmetric type IIB plane-wave background in the sector with J units of light-cone momentum is a supersymmetric 0+1 dimensional U(J) gauge theory (quantum mechanics) with PSU(2|2) x PSU(2|2) x U(1) superalgebra. The conjectured hamiltonian for the plane-wave matrix (string) theory, the tiny graviton matrix theory, is the quantized (regularized) three brane action on the same background. We present some pieces of evidence for this conjecture through analysis of the hamiltonian , its vacua, spectrum and coupling constant. Moreover, we discuss an extension of our conjecture to the DLCQ of type IIB strings on AdS{sub 5} x S{sup 5} geometry. (author)

  12. Reaction rate in an evanescent random walkers system

    CERN Document Server

    Ré, Miguel A

    2015-01-01

    Diffusion mediated reaction models are particularly ubiquitous in the description of physical, chemical or biological processes. The random walk schema is a useful tool for formulating these models. Recently, evanescent random walk models have received attention in order to include finite lifetime processes. For instance, activated chemical reactions, such as laser photolysis, exhibit a different asymptotic limit when compared with immortal walker models. A diffusion limited reaction model based on a one dimensional continuous time random walk on a lattice with evanescent walkers is presented here. The absorption probability density and the reaction rate are analytically calculated in the Laplace domain. A finite absorption rate is considered, a model usually referred to as imperfect trapping. Short and long time behaviors are analyzed.

  13. Friedman-Robertson-Walker Models with Late-Time Acceleration

    Institute of Scientific and Technical Information of China (English)

    Abdussattar; S. R. Prajapati2

    2011-01-01

    @@ In order to account for the observed cosmic acceleration, a modiGcation of the ansatz for the variation of density in Friedman-Robertson-Walker (FRW) FRW models given by Islam is proposed.The modified ansatz leads to an equation of state which corresponds to that of a variable Chaplygin gas, which in the course of evolution reduces to that of a modified generalized Chaplygin gas (MGCG) and a Chaplygin gas (CG), exhibiting late-time acceleration.%In order to account for the observed cosmic acceleration, a modification of the ansatz for the variation of density in Friedman-Robertson-Walker (FRW) FRW models given by Islam is proposed. The modified ansatz leads to an equation of state which corresponds to that of a variable Chaplygin gas, which in the course of evolution reduces to that ora modified generalized Chaplygin gas (MGCG) and a Chaplygin gas (CG), exhibiting late-time acceleration.

  14. The generalized Hodge and Bloch conjectures are equivalent for general complete intersections

    CERN Document Server

    Voisin, Claire

    2011-01-01

    Let $X$ be a smooth complex projective variety with trivial Chow groups. (By trivial, we mean that the cycle class is injective.) We show (assuming the Lefschetz standard conjecture) that if the vanishing cohomology of a general complete intersection $Y$ of ample hypersurfaces in $X$ has geometric coniveau $\\geq c$, then the Chow groups of cycles of dimension $\\leq c-1$ of $Y$ are trivial. The generalized Bloch conjecture for $Y$ is this statement with "geometric coniveau" replaced by "Hodge coniveau".

  15. Lang maps and Harris's conjecture a note in search for content

    CERN Document Server

    Abramovich, D

    1995-01-01

    The Lang map, namely the universal dominant rational map to a variety of general type, is constructed and briefly discussed in relation with arithmetic conjectures of Harris, Lang and Manin. Existence of the Lang map follows from the additivity of Kodaira dimension, but the fine structure depends on conjectures on birational classification of algebraic varieties. Serious applications of the Lang map are still being searched.

  16. Comparison Theorems for Eigenvalues of Elliptic Operators and the Generalized Polya Conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Wang Qiaoling, E-mail: wang@impa.br; Xia, Changyu, E-mail: xia@mat.unb.b [UnB, Departamento de Matematica (Brazil)

    2010-09-15

    We establish comparison theorems for eigenvalues between higher order elliptic equations on compact manifolds with boundary. As an application, it follows that if the Polya conjecture is true then so is the generalized Polya conjecture proposed by Ku et al. (J Differ Equ 97:127-139, 1992). We also obtain new lower bound for the eigenvalues of higher order elliptic equations on bounded domains in a Euclidean space.

  17. Matrix Models and A Proof of the Open Analog of Witten's Conjecture

    Science.gov (United States)

    Buryak, Alexandr; Tessler, Ran J.

    2017-08-01

    In a recent work, R. Pandharipande, J. P. Solomon and the second author have initiated a study of the intersection theory on the moduli space of Riemann surfaces with boundary. They conjectured that the generating series of the intersection numbers satisfies the open KdV equations. In this paper we prove this conjecture. Our proof goes through a matrix model and is based on a Kontsevich type combinatorial formula for the intersection numbers that was found by the second author.

  18. Record of Diglyphus walker (Hymenoptera: Eulophidae) species in Brazil.

    Science.gov (United States)

    Carvalho, A R; Bueno, V H P; Silva, D B; Costa, V A

    2011-01-01

    Leafminers (Diptera: Agromyzidae) are pests of various crops, mainly in greenhouses, and have Diglyphus spp. as important leafminer larval parasitoids. Until recently, only Diglyphus insularis (Gahan) had been reported in Brazil. In here we report the first records of Diglyphus begini (Ashmead), D. intermedius (Girault) and D. isaea (Walker) in Brazil. These parasitoids were found parasitizing leafminer larvae on cultivated and spontaneous plants in some areas of Minas Gerais state, Brazil.

  19. Friedman—Robertson—Walker Models with Late-Time Acceleration

    Science.gov (United States)

    Abdussattar; Prajapati, S. R.

    2011-02-01

    In order to account for the observed cosmic acceleration, a modification of the ansatz for the variation of density in Friedman—Robertson—Walker (FRW) FRW models given by Islam is proposed. The modified ansatz leads to an equation of state which corresponds to that of a variable Chaplygin gas, which in the course of evolution reduces to that of a modified generalized Chaplygin gas (MGCG) and a Chaplygin gas (CG), exhibiting late-time acceleration.

  20. Friedmann-Robertson-Walker Models with Late-Time Acceleration

    CERN Document Server

    Abdussattar,

    2016-01-01

    In order to account for the observed cosmic acceleration, a modification of the ansatz for the variation of density in Friedman-Robertson-Walker (FRW) models given by Islam is proposed. The modified ansatz leads to an equation of state which corresponds to that of a variable Chaplygin gas, which in the course of evolution reduces to that of a modified generalized Chaplygin gas (MGCG) and a Chaplygin gas (CG), exhibiting late-time acceleration.

  1. Alzheimer's Disease Facts and Figures

    Medline Plus

    Full Text Available ... with Alzheimer's >> Home Text size: A A A 2017 Alzheimer's Disease Facts and Figures Download the Full Report: ... More Alzheimer's Disease Facts in Each State The 2017 Alzheimer's Disease Facts and Figures report contains data on ...

  2. Alzheimer's Disease Facts and Figures

    Medline Plus

    Full Text Available ... Text size: A A A 2017 Alzheimer's Disease Facts and Figures Download the Full Report: Download the ... Costs Special Report Alzheimer's in each state Quick Facts Share the facts: Prevalence The number of Americans ...

  3. Facts about Mumps for Adults

    Science.gov (United States)

    ... Recommendation: MMR About Mumps Measles, Mumps, Rubella (MMR) Facts about Mumps for Adults What is Mumps? Mumps ... are pregnant or severely immunosuppressed. Disease and vaccine facts FACT: Mumps can be prevented with a safe ...

  4. Facts about Rubella for Adults

    Science.gov (United States)

    ... About Rubella (German Measles) Measles, Mumps, Rubella (MMR) Facts about Rubella for Adults What is rubella? Rubella, ... are pregnant or severely immunosuppressed. Disease and vaccine facts FACT: Rubella can be prevented with a safe ...

  5. Facts about Measles for Adults

    Science.gov (United States)

    ... a Glance Adolescent Vaccination Recommendation: MMR About Measles Facts about Measles for Adults What is measles? Measles ... are pregnant or severely immunosuppressed. Disease and vaccine facts FACT: Measles can be prevented with a safe ...

  6. Brain Aneurysm Statistics and Facts

    Science.gov (United States)

    ... Facts A- A A+ Brain Aneurysm Statistics and Facts An estimated 6 million people in the United ... Brain Warning Signs/ Symptoms Brain Aneurysm Statistics and Facts Seeking Medical Attention Risk Factors Aneurysm Complications Types ...

  7. Cohomologie non ramifi\\'ee et conjecture de Hodge enti\\`ere

    CERN Document Server

    Colliot-Thélène, Jean-Louis

    2010-01-01

    Building upon the Bloch-Kato conjecture in Milnor K-theory, we relate the third unramified cohomology group with Q/Z coefficients with a group which measures the failure of the integral Hodge conjecture in degree 4. As a first consequence, a geometric theorem of the second-named author implies that the third unramified cohomology group with Q/Z coefficients vanishes on all uniruled threefolds. As a second consequence, a 1989 example by Ojanguren and the first named author implies that the integral Hodge conjecture in degree 4 fails for unirational varieties of dimension at least 6. For certain classes of threefolds fibered over a curve, we establish a relation between the integral Hodge conjecture and the computation of the index of the generic fibre. --------- En nous appuyant sur la conjecture de Bloch-Kato en K-th\\'eorie de Milnor, nous \\'etablissons un lien g\\'en\\'eral entre le d\\'efaut de la conjecture de Hodge enti\\`ere pour la cohomologie de degr\\'e 4 et le troisi\\`eme groupe de cohomologie non ramifi\\...

  8. On the existence of perturbed Robertson-Walker universes

    Energy Technology Data Exchange (ETDEWEB)

    D' Eath, P.D.

    1976-05-01

    Solutions of the full nonlinear field equations of general relativity near the Robertson-Walker universes are examined, together with their relation to linearized perturbations. A method due to Choquet-Bruhat and Deser is used to prove existence theorems for solutions near Robertson-Walker constraint data of the constraint equations on a spacelike hypersurface. These theorems allow one to regard the matter fluctuations as independent quantities, ranging over certain function spaces. In the k=-1 case the existence theory describes perturbations which may vary within uniform bounds throughout space. When k=+1 a modification of the method leads to a theorem which clarifies some unusual features of these constraint perturbations. The k=0 existence theorem refers only to perturbations which die away at large distances. The connection between linearized constraint solutions and solutions of the full constraints is discussed. For k= +- 1 backgrounds, solutions of the linearized constraints are analyzed using transverse-traceless decompositions of symmetric tensors. Finally the time-evolution of perturbed constraint data and the validity of linearized perturbation theory for Robertson-Walker universes are considered. (AIP)

  9. Cosmic no-hair conjecture in scalar–tensor theories

    Indian Academy of Sciences (India)

    T Singh; R Chaubey

    2006-12-01

    We have shown that, within the context of scalar–tensor theories, the anisotropic Bianchi-type cosmological models evolve towards de Sitter Universe. A similar result holds in the case of cosmology in Lyra manifold. Thus the analogue of cosmic no-hair theorem of Wald [1] hold in both the cases. In fact, during inflation there is no difference between scalar–tensor theories, Lyra's manifold and general relativity (GR).

  10. Searching Exact Solutions for Compact Stars in Braneworld: a conjecture

    OpenAIRE

    2007-01-01

    In the context of the braneworld, a method to find consistent solutions to Einstein's field equations in the interior of a spherically symmetric, static and non uniform stellar distribution with Weyl stresses is developed. This method, based in the fact that any braneworld stellar solution must have the general relativity solution as a limit, produces a constraint which reduces the degrees of freedom on the brane. Hence the non locality and non closure of the braneworld equations can be overc...

  11. Faith, Fact, and Behaviorism.

    Science.gov (United States)

    Staddon, J E R

    2013-01-01

    David Hume argued that ought cannot be derived from is. That is, no set of facts, no amount of scientific knowledge, is by itself sufficient to urge us to action. Yet generations of well-meaning scientists (more and more as secular influences grow in the West) seem to have forgotten Hume's words of wisdom. All motivated action depends ultimately on beliefs that cannot be proved by the methods of science, that is, on faith.

  12. Faith, Fact, and Behaviorism

    OpenAIRE

    Staddon, J. E. R.

    2013-01-01

    David Hume argued that ought cannot be derived from is. That is, no set of facts, no amount of scientific knowledge, is by itself sufficient to urge us to action. Yet generations of well-meaning scientists (more and more as secular influences grow in the West) seem to have forgotten Hume's words of wisdom. All motivated action depends ultimately on beliefs that cannot be proved by the methods of science, that is, on faith.

  13. Arteriosclerosis: facts and fancy.

    Science.gov (United States)

    Fishbein, Michael C; Fishbein, Gregory A

    2015-01-01

    Arterial vascular diseases comprise the leading cause of death in the industrialized world. Every physician learns about the pathology of these diseases in medical school. All pathologists evaluate arterial disease in surgical pathology and/or autopsy specimens. All clinicians encounter patients with clinical manifestations of these diseases. With such a common and clinically-important group of entities one would think there would be a general understanding of the "known" information that exists. That is, physicians and scientists should be able to separate what is fact and what is fancy. This review article is intended to generate thought in this regard.

  14. Monitoring blazars with FACT

    Energy Technology Data Exchange (ETDEWEB)

    Mannheim, Karl [Lehrstuhl fuer Astronomie, Universitaet Wuerzburg (Germany)

    2012-07-01

    The FACT collaboration operates an imaging air-Cherenkov telescope on La Palma optimized for monitoring bright blazars. Recently, the collaboration reported a technological breakthrough. For the first time, avalanche photo diodes operated in Geiger mode have been employed in the camera. The low power consumption, high quantum efficiency, and high reliability of the novel semi-conductor based camera is the key to robotic operation needed for monitoring. Moreover, linearity permits observations even during moon light. Analysis of gamma-ray lightcurves of blazars holds the key to understand particle acceleration and its relation to the central engine.

  15. Chernobyl: the facts

    Energy Technology Data Exchange (ETDEWEB)

    Stanbridge, R. (Stockholm Univ. (Sweden) Dept. of Journalism, Media and Communication Studies)

    1993-08-01

    In these Search Strategies, searchers from different countries and professions are given a question to answer, a budget of Pounds 50 and a time in which to produce their report. We hope that these blow-by-blow accounts, together with the hints and tips picked up along the way, will help readers to develop their own search strategies. Journalists are more and more coming to use online services and here the author gives a journalist's account of tracking down the elusive facts surrounding the Chernobyl disaster. (author).

  16. Insulation fact sheet

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-08-01

    Electricity bills, oil bills, gas bills - all homeowners pay for one or more of these utilities, and wish they paid less. Often many of us do not really know how to control or reduce our utility bills. We resign ourselves to high bills because we think that is the price we have to pay for a comfortable home. We encourage our children to turn off the lights and appliances, but may not recognize the benefits of insulating the attic. This publication provides facts relative to home insulation. It discusses where to insulate, what products to use, the decision making process, installation options, and sources of additional information.

  17. Water: Facts without Myths

    Directory of Open Access Journals (Sweden)

    Marc Henry

    2009-08-01

    Full Text Available Among all the chemical substances available in the universe, water, with its deceptively simple formula H2O, is the most discussed subject either in science or in philosophy [1]. If you are not convinced by this affirmation, a little experiment at no cost may help you change your mind. Just open your favorite web browser and type the word “water” in any search engine. When I have done that using Google, the number of hits was about 682,000,000 (please do not try to read all the pages. In fact, the only words that seem to beat water at this little game are “air” (770,000,000 hits with Google and 3,120,000,000 with Yahoo, and “food” (689,000,000 hits with Google and 3,820,000,000 with Yahoo. Of course this should not be a surprise, as breathing, eating, drinking just mean that you are a living entity. In fact extending the water search to “eau” (French, “wasser” (German, “agua” (Spanish, Portuguese and “acqua” (Italian leads to 978,900,000 hits under Google and 3,426,000,000 hits under Yahoo, showing now that water is about as important as food. After all, as everybody knows, “water is life”, and do we really have to read about one billion documents to know at least what water really is? [...

  18. Mechanical-Kinetic Modeling of a Molecular Walker from a Modular Design Principle

    Science.gov (United States)

    Hou, Ruizheng; Loh, Iong Ying; Li, Hongrong; Wang, Zhisong

    2017-02-01

    Artificial molecular walkers beyond burnt-bridge designs are complex nanomachines that potentially replicate biological walkers in mechanisms and functionalities. Improving the man-made walkers up to performance for widespread applications remains difficult, largely because their biomimetic design principles involve entangled kinetic and mechanical effects to complicate the link between a walker's construction and ultimate performance. Here, a synergic mechanical-kinetic model is developed for a recently reported DNA bipedal walker, which is based on a modular design principle, potentially enabling many directional walkers driven by a length-switching engine. The model reproduces the experimental data of the walker, and identifies its performance-limiting factors. The model also captures features common to the underlying design principle, including counterintuitive performance-construction relations that are explained by detailed balance, entropy production, and bias cancellation. While indicating a low directional fidelity for the present walker, the model suggests the possibility of improving the fidelity above 90% by a more powerful engine, which may be an improved version of the present engine or an entirely new engine motif, thanks to the flexible design principle. The model is readily adaptable to aid these experimental developments towards high-performance molecular walkers.

  19. Beyond the Friedmann-Lemaatre-Robertson-Walker Big Bang Singularity

    Institute of Scientific and Technical Information of China (English)

    Cristi Stoica

    2012-01-01

    Einstein's equation,in its standard form,breaks down at the Big Bang singularity.A new version,equivalent to Einstein's whenever the latter is defined,but applicable in wider situations,is proposed.The new equation remains smooth at the Big Bang singularity of the Friedmann-Lemaatre-Robertson-Walker model.It is a tensor equation defined in terms of the Ricci part of the Riemann curvature.It is obtained by taking the Kulkarni-Nomizu product between Einstein's equation and the metric tensor.

  20. The insecticide resistance in stripped stem borer, Chilo suppressalis (Walker)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ The stripped stem borer (SSB), Chilo suppressalis (Walker) is one of the major insect pests of rice in China. Chemical control has been a common practice in SSB management since 1950s. Insecticides used included BHC before 1983;organophosphorus insecticides (methyl-parathion, trichophon, methamidophos, and monocrotophos), and chlordimeform in mid-1970s-1980s; Shachongshuang (dimehypo) and Shachongdan (monousltap) since early 1980s. In recent years, SSB population and its damage to rice increased rapidly and failures on control has been reported. To find out the cause of failure and to put forward the suitable control methods, we studied the resistance of SSB to major insecticides used in China.

  1. Number of distinct sites visited by a subdiffusive random walker.

    Science.gov (United States)

    Yuste, Santos Bravo; Klafter, J; Lindenberg, Katja

    2008-03-01

    The asymptotic mean number of distinct sites visited by a subdiffusive continuous-time random walker in two dimensions seems not to have been explicitly calculated anywhere in the literature. This number has been calculated for other dimensions for only one specific asymptotic behavior of the waiting time distribution between steps. We present an explicit derivation for two cases in all integer dimensions so as to formally complete a tableau of results. In this tableau we include the dominant as well as subdominant contributions in all integer dimensions. Other quantities that can be calculated from the mean number of distinct sites visited are also discussed.

  2. On signature transition in Robertson-Walker cosmologies

    CERN Document Server

    Ghafoori-Tabrizi, K; Sepangi, H R

    2000-01-01

    We analyse a classical model of gravitation coupled to a self interacting scalar field. We show that, within the context of this model for Robertson-Walker cosmologies, there exist solutions in the spatially non-flat cases exhibiting transitions from a Euclidean to a Lorentzian spacetime. We then discuss the conditions under which these signature changing solutions to Einstein's field equations exist. In particular, we find that an upper bound for the cosmological constant exists and that close to the signature changing hypersurface, both the scale factor and the scalar field have to be constant. Moreover we find that the signature changing solutions do not exist when the scalar field is massless.

  3. Difficulties with Prenatal Diagnosis of the Walker-Warburg Syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Low, A.S.C.; Lee, S.L.; Tan, A.S.A.; Chan, D.K.L.; Chan, L.L. [Singapore General Hospital (Singapore). Depts. of Diagnostic Radiology, Obstetrics and Gynecology and Neonatology

    2005-10-01

    We describe a postnatally diagnosed case of Walker-Warburg syndrome - a form of congenital muscular dystrophy with lissencephaly and eye abnormalities. We reviewed the literature to highlight its clinico-radiological diagnostic features and discuss the difficulties encountered with prenatal diagnosis, especially in cases with no positive family history. An increased awareness of this rare but lethal condition, and a high index of suspicion during routine antenatal ultrasound, could prompt further advanced fetal ultrasonography and magnetic resonance imaging, and aid in timely prenatal diagnosis, management, and counseling. Brain/brainstem, congenital, magnetic resonance imaging, obstetrics, pediatrics, ultrasound.

  4. Le fonds Alexander Walker de la Cineteca di Friouli

    OpenAIRE

    Codelli, Lorenzo

    2012-01-01

    La Collection Alexander Walker conservée à la Bibliothèque Angelo R. Humouda de la Cineteca del Friuli, à Gemona, Italie, inclût le patrimoine libraire entier, ainsi que la correspondence et tous les manuscripts d’un des critiques et essayistes anglosaxons les plus connus et influents de sa génération. Ses polémiques contre la censure, sa collaboration avec Stanley Kubrick pour la toute première monographie parue sur l’auteur de 2001 : L’Odyssée de l’espace, ses recherches fouillées sur Josep...

  5. Gravitational birefringence of light in Robertson-Walker cosmologies

    CERN Document Server

    Duval, C

    2016-01-01

    The spacetime evolution of massless spinning particles in a Robertson-Walker background is derived using the deterministic system of equations of motion due to Papapetrou, Souriau and Saturnini. A numerical integration of this system of differential equations in the case of the standard model is performed. The deviation of the photon worldlines from the null geodesics is of the order of the wavelength. Perturbative solutions are also worked out in a more general case. An experimental measurement of this deviation would test the acceleration of our expanding universe.

  6. Photovoltaics Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-02-01

    This fact sheet is an overview of the Photovoltaics (PV) subprogram at the U.S. Department of Energy SunShot Initiative. The U.S. Department of Energy (DOE)’s Solar Energy Technologies Office works with industry, academia, national laboratories, and other government agencies to advance solar PV, which is the direct conversion of sunlight into electricity by a semiconductor, in support of the goals of the SunShot Initiative. SunShot supports research and development to aggressively advance PV technology by improving efficiency and reliability and lowering manufacturing costs. SunShot’s PV portfolio spans work from early-stage solar cell research through technology commercialization, including work on materials, processes, and device structure and characterization techniques.

  7. Soft Costs Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-05-01

    This fact sheet is an overview of the systems integration subprogram at the U.S. Department of Energy SunShot Initiative. Soft costs can vary significantly as a result of a fragmented energy marketplace. In the U.S., there are 18,000 jurisdictions and 3,000 utilities with different rules and regulations for how to go solar. The same solar equipment may vary widely in its final installation price due to process and market variations across jurisdictions, creating barriers to rapid industry growth. SunShot supports the development of innovative solutions that enable communities to build their local economies and establish clean energy initiatives that meet their needs, while at the same time creating sustainable solar market conditions.

  8. Psychoacoustics Facts and Models

    CERN Document Server

    Fastl, Hugo

    2007-01-01

    Psychoacoustics – Facts and Models offers a unique, comprehensive summary of information describing the processing of sound by the human hearing system. It includes quantitative relations between sound stimuli and auditory perception in terms of hearing sensations, for which quantitative models are given, as well as an unequalled collection of data on the human hearing system as a receiver of acoustic information. In addition, many examples of the practical application of the results of basic research in fields such as noise control, audiology, or sound quality engineering are detailed. The third edition includes an additional chapter on audio-visual interactions and applications, plus more on applications throughout. Reviews of previous editions have characterized it as "an essential source of psychoacoustic knowledge," "a major landmark ," and a book that "without doubt will have a long-lasting effect on the standing and future evolution of this scientific domain."

  9. Systems Integration Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-06-01

    This fact sheet is an overview of the Systems Integration subprogram at the U.S. Department of Energy SunShot Initiative. The Systems Integration subprogram enables the widespread deployment of safe, reliable, and cost-effective solar energy technologies by addressing the associated technical and non-technical challenges. These include timely and cost-effective interconnection procedures, optimal system planning, accurate prediction of solar resources, monitoring and control of solar power, maintaining grid reliability and stability, and many more. To address the challenges associated with interconnecting and integrating hundreds of gigawatts of solar power onto the electricity grid, the Systems Integration program funds research, development, and demonstration projects in four broad, interrelated focus areas: grid performance and reliability, dispatchability, power electronics, and communications.

  10. On the Erdős-Gyárfás Conjecture in Claw-Free Graphs

    Directory of Open Access Journals (Sweden)

    Nowbandegani Pouria Salehi

    2014-08-01

    Full Text Available The Erdős-Gyárfás conjecture states that every graph with minimum degree at least three has a cycle whose length is a power of 2. Since this conjecture has proven to be far from reach, Hobbs asked if the Erdős-Gyárfás conjecture holds in claw-free graphs. In this paper, we obtain some results on this question, in particular for cubic claw-free graphs

  11. The generalized Kac-Wakimoto conjecture and support varieties for the Lie superalgebra osp(m|2n)

    CERN Document Server

    Kujawa, Jonathan

    2011-01-01

    Atypicality is a fundamental combinatorial invariant for simple supermodules of a basic Lie superalgebra. Boe, Nakano, and the author gave a conjectural geometric interpretation of atypicality via support varieties. Inspired by low dimensional topology, Geer, Patureau-Mirand, and the author gave a generalization of the Kac-Wakimoto atypicality conjecture. We prove both of these conjectures for the Lie superalgebra osp(m|2n).

  12. Conjectures and experiments concerning the moments of $L(1/2,\\chi_d)$

    CERN Document Server

    Alderson, Matthew W

    2011-01-01

    We report on some extensive computations and experiments concerning the moments of quadratic Dirichlet $L$-functions at the critical point. We computed the values of $L(1/2,\\chi_d)$ for $- 5\\times 10^{10} < d < 1.3 \\times 10^{10}$ in order to numerically test conjectures concerning the moments $\\sum_{|d|conjectured by Conrey, Farmer, Keating, Rubinstein, and Snaith, as well as the conjectures of Diaconu, Goldfeld, Hoffstein, and Zhang concerning additional lower terms in the moments. We also describe the algorithms used for this large scale computation.

  13. Revisiting the Zassenhaus conjecture on torsion units for the integral group rings of small groups

    Indian Academy of Sciences (India)

    Allen Herman; Gurmail Singh

    2015-05-01

    In recent years several new restrictions on integral partial augmentations for torsion units of $\\mathbb{Z}G$ have been introduced, which have improved the effectiveness of the Luthar–Passi method for checking the Zassenhaus conjecture for specific groups . In this note, we report that the Luthar–Passi method with the new restrictions are sufficient to verify the Zassenhaus conjecture with a computer for all groups of order less than 96, except for one group of order 48 – the non-split covering group of 4, and one of order 72 of isomorphism type ( × ) × 8. To verify the Zassenhaus conjecture for this group we give a new construction of normalized torsion units of $\\mathbb{Q}G$ that are not conjugate to elements of $\\mathbb{Z}G$.

  14. Disproving the Peres conjecture by showing Bell nonlocality from bound entanglement.

    Science.gov (United States)

    Vértesi, Tamás; Brunner, Nicolas

    2014-11-05

    Quantum entanglement has a central role in many areas of physics. To grasp the essence of this phenomenon, it is fundamental to understand how different manifestations of entanglement relate to each other. In 1999, Peres conjectured that Bell nonlocality is equivalent to distillability of entanglement. The intuition of Peres was that the non-classicality of an entangled state, as witnessed via Bell inequality violation, implies that pure entanglement can be distilled from this state, hence making it useful for quantum information protocols. Subsequently, the Peres conjecture was shown to hold true in several specific cases, and became a central open question in quantum information theory. Here we disprove the Peres conjecture by showing that an undistillable bipartite entangled state--a bound entangled state--can violate a Bell inequality. Hence Bell nonlocality implies neither entanglement distillability, nor non-positivity under partial transposition. This clarifies the relation between three fundamental aspects of entanglement.

  15. Some answer to Nivat's conjecture: A characterization of periodicity with respect to block complexity

    CERN Document Server

    Durand, Fabien

    2011-01-01

    Nivat's conjecture is about the link between the pure periodicity of a subset $M$ of $\\ZZ^2$, i.e., invariance under translation by a fixed vector, and some upper bound on the function counting the number of different rectangular blocks occurring in $M$. Attempts to solve this conjecture have been considered during the last fifteen years. Let $d\\ge 2$. A legitimate extension to a multidimensional setting of the notion of periodicity is to consider sets of $\\ZZ^d$ definable by a first order formula in the Presburger arithmetic $$. With this latter notion and using a powerful criterion due to Muchnik, we solve an analogue of Nivat's conjecture and characterize sets of $\\ZZ^d$ definable in $$ in terms of some functions counting recurrent blocks, that is, blocks occurring infinitely often.

  16. Inequalities relating to Lp-version of Petty's conjectured projection inequality

    Institute of Scientific and Technical Information of China (English)

    WANG Wei-dong; LENG Gang-song

    2007-01-01

    Petty's conjectured projection inequality is a famous open problem in the theory of convex bodies. In this paper, it is shown that an inequality relating to Lp-version of the Petty's conjectured projection inequality is developed by using the notions of the Lp-mixed volume and the Lp-dual mixed volume, the relation of the Lp-projection body and the geometric body Γ-pK, the Bourgain-Milman inequality and the Lp-BusemannPetty inequality. In addition, for each origin-symmetric convex body, by applying the Jensen inequality and the monotonicity of the geometric body Γ-pK, the reverses of Lp-version of the Petty's conjectured projection inequality and the Lp-Petty projection inequality are given, respectively.

  17. Modelo experimental do carcinossarcoma 256 de Walker em bexiga de ratos Experimental model of Walker 256 carcinosarcoma in rats bladder

    Directory of Open Access Journals (Sweden)

    Conceição Aparecida Dornelas

    2006-02-01

    Full Text Available OBJETIVO: Estudar um modelo animal para tumor de bexiga com Walker 256. MÉTODOS: Bexigas de ratos Wistar foram cateterizadas via uretral e lesão de parede vesical foi realizada por compressão extrínsica, com pequena pinça, após laparotomia. A seguir 0,3 ml de suspensão contendo 3 x 10(5 células viáveis de carcinossarcoma de Walker foram instiladas em cada bexiga. Os animais foram sacrificados após oito e 13 dias. RESULTADOS: O índice de pega do tumor foi de 100%. A média de sobrevida foi de 14,5 dias. CONCLUSÃO: O modelo estudado foi eficiente e poderá levar subsídios para o estudo experimental em tratamentos de carcinomas de bexiga localmente invasivos em ratos.PURPOSE: An animal model to study bladder tumor with Walker 256. METHODS: Bladders rats Wistar was catheterized via urethra and compression lesion of the wall bladder was realized with a little clamping after laparotomy. One total of the 0,3 ml suspension with 3 x 10(5 cels viable of the carcinossarcoma was instilled into each bladder. The animals were sacrificed after eight and 13 days. RESULTS: The index of tumor incidence was 100% and the average of surviving was 14,5 days. CONCLUSION: The model estudied was efficient and will can to take subsidy the study experiemental in treatment of local invasise bladder cancer.

  18. De Narciso López a William Walker. El contingente anexionista cubano dentro de las huestes filibusteras de Walker

    OpenAIRE

    Suárez-Serrano, Josefina M.

    2016-01-01

    Examino la continuidad  entre  las actividades del caudillo del anexionismo cubano, Narciso López, y las del capitán de filibusteros norteamericano William Walker, en cuanto exponentes de los intereses del  recalcitrante esclavismo  del Sur y otras regiones de los Estados Unidos: de su programa y de sus tácticas, que apuntaban  a  la expansión ilimitada  de la esclavitud a expensas de México, Centroamérica y las Antillas.

  19. FreeWalker: a smart insole for longitudinal gait analysis.

    Science.gov (United States)

    Wang, Baitong; Rajput, Kuldeep Singh; Tam, Wing-Kin; Tung, Anthony K H; Yang, Zhi

    2015-08-01

    Gait analysis is an important diagnostic measure to investigate the pattern of walking. Traditional gait analysis is generally carried out in a gait lab, with equipped force and body tracking sensors, which needs a trained medical professional to interpret the results. This procedure is tedious, expensive, and unreliable and makes it difficult to track the progress across multiple visits. In this paper, we present a smart insole called FreeWalker, which provides quantitative gait analysis outside the confinement of traditional lab, at low- cost. The insole consists of eight pressure sensors and two motion tracking sensors, i.e. 3-axis accelerometer and 3-axis gyroscope. This enables measurement of under-foot pressure distribution and motion sequences in real-time. The insole is enabled with onboard SD card as well as wireless data transmission, which help in continuous gait-cycle analysis. The data is then sent to a gateway, for analysis and interpretation of data, using a user interface where gait features are graphically displayed. We also present validation result of a subject's left foot, who was asked to perform a specific task. Experiment results show that we could achieve a data-sampling rate of over 1 KHz, transmitting data up to a distance of 20 meter and maintain a battery life of around 24 hours. Taking advantage of these features, FreeWalker can be used in various applications, like medical diagnosis, rehabilitation, sports and entertainment.

  20. SYMMETRY AS CONCEPTUAL METAPHOR IN WALKER'S THE COLOR PURPLE

    Directory of Open Access Journals (Sweden)

    Elena Tapia

    2003-05-01

    Full Text Available The author analyzes three types of the conceptual metaphor of embodied symmetry in Alice Walker's novel, The color purple (1982. These metaphorical projections, perceived as equilibrium and its breakage in abstract phenomena, enable readers to reexamine issues of race, non-traditional families, and gender roles. The dis/equilibrium emerges in the novel's epistolary structure. Biological equilibrium breaks in incidents of rape and incest. Walker creates characters in the novel through default-concept opposites of black/white, submissive/dominant, male/female and others. These contraries foreground issues of race and gender. The novel's asymmetries engage readers, leading them to rethink individual character histories and motives. The removal of objects (e.g., rape, mothers deprived of children suggests conceptual asymmetry and alerts readers to parallel themes of sexual and racial oppression. Subjugation sometimes subtle, sometimes blatant- manifests in simple oppositions. In epistemological terms, readers seek causal explanations for the asymmetries of the narrative, interpreting each to recover its history.

  1. [Aicardi syndrome with Dandy-Walker type malformation].

    Science.gov (United States)

    Laguado-Herrera, Yuly V; Manrique-Hernández, Edgar F; Peñaloza-Mantilla, Camilo A; Quintero-Gómez, David A; Contreras-García, Gustavo A; Sandoval-Martínez, Diana K

    2015-07-16

    Introduccion. El sindrome de Aicardi (OMIM 304050) fue descrito en 1965. Su triada clasica esta compuesta por espasmos infantiles, agenesia parcial o total del cuerpo calloso y alteraciones oculares, como lagunas coriorretinianas. Se postula un mecanismo de herencia ligado a X dominante. Caso clinico. Niña nacida a termino, sin antecedentes familiares patologicos ni consanguinidad parental, con diagnostico prenatal de malformacion tipo Dandy-Walker, quien presento episodios convulsivos, coloboma del nervio optico, bloque vertebral toracico con presencia de escoliosis, ecografia transfontanelar con agenesia del cuerpo calloso y cariotipo 46,XX. Se diagnostico de sindrome de Aicardi y fallecio con mes y medio de edad. En la autopsia se evidencio hidrocefalia supratentorial con presencia de papiloma de los plexos coroideos, quiste en la fosa posterior (cuarto ventriculo), hipoplasia del vermis cerebeloso, agenesia del hemisferio del cuerpo calloso y cerebeloso izquierdo, rasgos faciales caracteristicos del sindrome, paladar ojival, pectus excavatum, escoliosis, quiste paraovarico y hepatomegalia. Conclusiones. Pocos casos han descrito la asociacion de la patologia y la presencia de malformacion de Dandy-Walker. Se comunica un nuevo caso con esta asociacion, teniendo en cuenta que las alteraciones relacionadas, principalmente agenesia o hipoplasia del cuerpo calloso, sugieren que tiene un componente genetico de base. El estudio de busqueda de la etiologia de centrarse en evaluar aquellos genes que tengan relacion con el neurodesarrollo y su activacion en la etapa de organogenia. El diagnostico definitivo establece el pronostico, manejo y asesoria genetica a la familia.

  2. Optimal recruitment strategies for groups of interacting walkers with leaders

    Science.gov (United States)

    Martínez-García, Ricardo; López, Cristóbal; Vazquez, Federico

    2015-02-01

    We introduce a model of interacting random walkers on a finite one-dimensional chain with absorbing boundaries or targets at the ends. Walkers are of two types: informed particles that move ballistically towards a given target and diffusing uninformed particles that are biased towards close informed individuals. This model mimics the dynamics of hierarchical groups of animals, where an informed individual tries to persuade and lead the movement of its conspecifics. We characterize the success of this persuasion by the first-passage probability of the uninformed particle to the target, and we interpret the speed of the informed particle as a strategic parameter that the particle can tune to maximize its success. We find that the success probability is nonmonotonic, reaching its maximum at an intermediate speed whose value increases with the diffusing rate of the uninformed particle. When two different groups of informed leaders traveling in opposite directions compete, usually the largest group is the most successful. However, the minority can reverse this situation and become the most probable winner by following two different strategies: increasing its attraction strength or adjusting its speed to an optimal value relative to the majority's speed.

  3. Metalloproteins during development of Walker-256 carcinosarcoma resistant phenotype

    Directory of Open Access Journals (Sweden)

    V. F. Chekhun

    2015-04-01

    Full Text Available The study was focused on the detection of changes in serum and tumor metal-containing proteins in animals during development of doxorubicin-resistant phenotype in malignant cells after 12 courses of chemotherapy. We found that on every stage of resistance development there was a significant increase in content of ferritin and transferrin proteins (which take part in iron traffick and storage in Walker-256 carcinosarcoma tissue. We observed decreased serum ferritin levels at the beginning stage of the resistance development and significant elevation of this protein levels in the cases with fully developed resistance phenotype. Transferrin content showed changes opposite to that of ferritin. During the development of resistance phenotype the tumor tissue also exhibited increased ‘free iron’ concentration that putatively correlate with elevation of ROS generation and levels of MMP-2 and MMP-9 active forms. The tumor non-protein thiol content increases gradually as well. The serum of animals with early stages of resistance phenotype development showed high ceruloplasmin activity and its significant reduction after loss of tumor sensitivity to doxorubicin. Therefore, the development of resistance phenotype in Walker-256 carcinosarcoma is accompanied by both the deregulation of metal-containing proteins in serum and tumor tissue and by the changes in activity of antioxidant defense system. Thus, the results of this study allow us to determine the spectrum of metal-containing proteins that are involved in the development of resistant tumor phenotype and that may be targeted for methods for doxorubicin sensitivity correction therapy.

  4. Fuzzy Random Walkers with Second Order Bounds: An Asymmetric Analysis

    Directory of Open Access Journals (Sweden)

    Georgios Drakopoulos

    2017-03-01

    Full Text Available Edge-fuzzy graphs constitute an essential modeling paradigm across a broad spectrum of domains ranging from artificial intelligence to computational neuroscience and social network analysis. Under this model, fundamental graph properties such as edge length and graph diameter become stochastic and as such they are consequently expressed in probabilistic terms. Thus, algorithms for fuzzy graph analysis must rely on non-deterministic design principles. One such principle is Random Walker, which is based on a virtual entity and selects either edges or, like in this case, vertices of a fuzzy graph to visit. This allows the estimation of global graph properties through a long sequence of local decisions, making it a viable strategy candidate for graph processing software relying on native graph databases such as Neo4j. As a concrete example, Chebyshev Walktrap, a heuristic fuzzy community discovery algorithm relying on second order statistics and on the teleportation of the Random Walker, is proposed and its performance, expressed in terms of community coherence and number of vertex visits, is compared to the previously proposed algorithms of Markov Walktrap, Fuzzy Walktrap, and Fuzzy Newman–Girvan. In order to facilitate this comparison, a metric based on the asymmetric metrics of Tversky index and Kullback–Leibler divergence is used.

  5. Reduction of the Hall-Paige conjecture to sporadic simple groups

    CERN Document Server

    Wilcox, Stewart

    2010-01-01

    A complete mapping of a group $G$ is a permutation $\\phi:G\\rightarrow G$ such that $g\\mapsto g\\phi(g)$ is also a permutation. Complete mappings of $G$ are equivalent to tranversals of the Cayley table of $G$, considered as a latin square. In 1953, Hall and Paige proved that a finite group admits a complete mapping only if its Sylow-2 subgroup is trivial or non-cyclic. They conjectured that this condition is also sufficient. We prove that it is sufficient to check the conjecture for the 26 sporadic simple groups and the Tits group.

  6. Anisotropic Power-law Inflation: A counter example to the cosmic no-hair conjecture

    CERN Document Server

    Soda, Jiro

    2014-01-01

    It is widely believed that anisotropy in the expansion of the universe will decay exponentially fast during inflation. This is often referred to as the cosmic no-hair conjecture. However, we find a counter example to the cosmic no-hair conjecture in the context of supergravity. As a demonstration, we present an exact anisotropic power-law inflationary solution which is an attractor in the phase space. We emphasize that anisotropic inflation is quite generic in the presence of anisotropic sources which couple with an inflaton.

  7. Woltjer-Taylor State Without Taylor's Conjecture - Plasma Relaxation at all Wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Hong; Liu, Wandong; Li, Hong; Squire, Jonathan

    2012-10-10

    In astrophysical and laboratory plasmas, it has been discovered that plasmas relax towards the well-known Woltjer-Taylor state specified by ∇ x B = αB for a constant α . To explain how such a relaxed state is reached, Taylor developed his famous relaxation theory based on the conjecture that the relaxation is dominated by short wavelength fluctuations. However, there is no conclusive experimental and numerical evidence to support Taylor's conjecture. A new theory is developed, which predicts that the system will evolve towards the Woltjer-Taylor state for an arbitrary fluctuation spectrum.

  8. A proof of the $\\ell$-adic version of the integral identity conjecture for polynomials

    CERN Document Server

    Thuong, Le Quy

    2012-01-01

    We consider the $\\ell$-adic version of the integral identity conjecture and give a complete proof in the case of polynomials. This conjecture is among of the key foundations of the theory of motivic Donaldson-Thomas invariants for non-commutative 3d Calabi-Yau varieties, which was introduced recently by Kontsevich and Soibelman. Our approach is to use some results on the Berkovich spaces, specially the comparison theorem for nearby cycles and the K$\\ddot{\\text{u}}$nneth isomorphism for cohomology with compact support.

  9. Alzheimer's Disease Facts and Figures

    Medline Plus

    Full Text Available ... without Alzheimer's — a rate twice as high. Invest in a world without Alzheimer's. Donate Caregivers In 2016, ... COMMITMENT TO RESEARCH. Read More Alzheimer's Disease Facts in Each State The 2017 Alzheimer's Disease Facts and ...

  10. Facts about Sickle Cell Disease

    Science.gov (United States)

    ... Websites About Us Information For… Media Policy Makers Facts About Sickle Cell Disease Language: English (US) Españ ... usually a milder form of SCD. Infographic: 5 Facts You Should Know About Sickle Cell Disease Did ...

  11. Wormholes, emergent gauge fields, and the weak gravity conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Harlow, Daniel [Center for the Fundamental Laws of Nature, Physics Department, Harvard University,Cambridge MA, 02138 (United States)

    2016-01-20

    This paper revisits the question of reconstructing bulk gauge fields as boundary operators in AdS/CFT. In the presence of the wormhole dual to the thermofield double state of two CFTs, the existence of bulk gauge fields is in some tension with the microscopic tensor factorization of the Hilbert space. I explain how this tension can be resolved by splitting the gauge field into charged constituents, and I argue that this leads to a new argument for the “principle of completeness”, which states that the charge lattice of a gauge theory coupled to gravity must be fully populated. I also claim that it leads to a new motivation for (and a clarification of) the “weak gravity conjecture”, which I interpret as a strengthening of this principle. This setup gives a simple example of a situation where describing low-energy bulk physics in CFT language requires knowledge of high-energy bulk physics. This contradicts to some extent the notion of “effective conformal field theory”, but in fact is an expected feature of the resolution of the black hole information problem. An analogous factorization issue exists also for the gravitational field, and I comment on several of its implications for reconstructing black hole interiors and the emergence of spacetime more generally.

  12. FACTS technology for open access

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    Summary of the present state of the art on the key technological developments in the FACTS (Flexible AC Transmission Systems) area, addressing in particular the open access aspects of networks and the scope for the application of FACTS devices therein. Contains the approved terms of reference. Definition of FACTS includes conventional devices such as phase shifting transformers, series capacitors and HVDC links for completeness and the possibility of combining them with FACTS devices to improve HVAC transmission system flexibility and control. (author)

  13. Facts, values, and journalism.

    Science.gov (United States)

    Gilbert, Susan

    2017-03-01

    At a time of fake news, hacks, leaks, and unverified reports, many people are unsure whom to believe. How can we communicate in ways that make individuals question their assumptions and learn? My colleagues at The Hastings Center and many journalists and scientists are grappling with this question and have, independently, reached the same first step: recognize that facts can't be fully understood without probing their connection to values. "Explaining the basics is important, of course, but we also need to diversify our approach to the coverage of science-particularly as it intersects with the matrix of cultural, religious, social, and political values of our readers," said an article in Undark, an online magazine of science journalism. An editorial in Nature called for scientists to engage directly with citizens in debates over climate change and genome editing, noting that "the ethical issues can be critically dependent on the science, for example, in understanding where the boundaries between non-heritable and heritable genome modifications might be." We're here to help. © 2017 The Hastings Center.

  14. Low Back Pain Fact Sheet

    Science.gov (United States)

    ... Low Back Pain Fact Sheet You are here Home » Disorders » Patient & Caregiver Education » Fact Sheets Low Back Pain Fact Sheet What ... reduction among workers using lumbar support belts, many companies that have ... training and ergonomic awareness programs. The reported injury reduction ...

  15. John Searle on Institutional Facts

    Directory of Open Access Journals (Sweden)

    m Abdullahi

    2010-09-01

    Here we argue that the essence of institutional facts is status functions. Humans recognize these functions which contain a set of deontic powers through collective intentionality. Therefore, institutional facts are ontologically subjective and epistemologically objective. Nevertheless, objectivity of institutional facts totally depends on language which itself is a fundamental institution for other institutions.

  16. The Zero Active Mass Condition in Friedmann-Robertson-Walker Cosmologies

    CERN Document Server

    Melia, Fulvio

    2016-01-01

    Many cosmological measurements today suggest that the Universe is expanding at a constant rate. This is inferred from the observed age versus redshift relationship and various distance indicators, all of which point to a cosmic equation of state (EoS) p=-rho/3, where rho and p are, respectively, the total energy density and pressure of the cosmic fluid. It has recently been shown that this result is not a coincidence and simply confirms the fact that the symmetries in the Friedmann-Robertson-Walker (FRW) metric appear to be viable only for a medium with zero active mass, i.e., rho+3p=0. In their latest paper, however, Kim, Lasenby and Hobson have provided what they believe to be a counter argument to this conclusion. Here, we show that these authors are merely repeating the conventional mistake of incorrectly placing the observer simultaneously in a co-moving frame, where the lapse function g_tt is coordinate dependent when rho+3p is not 0, and a supposedly different, free-falling frame, in which g_tt=1, impl...

  17. Integrating SLAM with existing evidence: Comment on Walker and Hickok (2015).

    Science.gov (United States)

    Goldrick, Matthew

    2016-04-01

    Walker and Hickok (Psychonomic Bulletin & Review doi:10.3758/s13423-015-0903-7, 2015) used simulations to compare a novel proposal, the semantic-lexical-auditory-motor model (SLAM), to an existing account of speech production, the two-step interactive account (TSIA; Foygel & Dell, Journal of Memory and Language, 43:182-216, doi:10.1006/jmla.2000.2716, 2000). This commentary critically examines their assessment of SLAM. The cases in which SLAM outperforms TSIA largely reflect SLAM's ability to (poorly) approximate an existing theory of speech production incorporating two stages of phonological processing (the lexical + postlexical account). The fact that SLAM and TSIA can exhibit equivalent fits to the overall response distribution of a set of aphasic patients is unsurprising, since previous work has shown that overall response distributions do not reliably discriminate theoretical alternatives. Finally, SLAM inherits issues associated with TSIA's assumption of strong feedback between levels of representation. This suggests that SLAM does not represent an advance over existing theories of speech production.

  18. Wrist joint moments of walker-assisted gait:a study of biomechanics and instrumentation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    While walkers are commonly prescribed to improve patient stability and ambulatory ability,quantitativestudy of the biomechanical and functional requirements for effective walker use is limited.To investigate the changesin wrist joint moments that occur with the use of a standard walker,a strain gauge-based walker instrumentation system was developed for the measurement of wrist joint moments.This walker dynamometer was integrated with an upper extremity biomechanical model.Preliminary system data were collected for twelve healthy,right-handed young adultsfollowing informed consent.Bilateral upper extremity kinematic data were acquired with a six-camera motion analysis system.Internal joint moments at the wrist were determined in the three clinical planes using the inverse dynamics method.Results showed that during a walker-assisted gait there were several typical demands of wrist abductor,adductor,flexor and external rotator.An interesting " bare phase " of wrist joint moments was also found in phaseangle[-30°,30°] of gait cycle.Complete description of wrist joint moments during walker-assisted gait may provide insight into walker use parameters and rehabilitative strategies.

  19. Tax evasion in transition: Outcome of an institutional clash? - Testing Feige's conjecture in Albania

    NARCIS (Netherlands)

    K. Gërxhani

    2004-01-01

    A field survey of households was conducted in Tirana, Albania in 2000. A response rate of 89.3% yielded 1.340 valid questionnaires, allowing me to test Feige's (In: Nelson, J.M., Tilley, C., Walker, L. (Eds.), Transforming Post-communist Political Economics. National Academy Press, Washington, DC, p

  20. The Hodge conjecture for self-products of certain K3 surfaces

    CERN Document Server

    Schlickewei, Ulrich

    2009-01-01

    We use a result of van Geemen to determine the endomorphism algebra of the Kuga--Satake variety of a K3 surface with real multiplication. This is applied to prove the Hodge conjecture for self-products of double covers of $\\PP^2$ which are ramified along six lines.