bluuebunny/crossref_metadata_2025_split huggingface dataset:
Submanifolds with Nonparallel First Normal Bundle
Authors: Dajczer Marcos , Tojeiro Ruy 
Published: December 2010

AbstractWe provide a complete local geometric description of submanifolds of spaces with constant sectional curvature where the first normal spaces, that is, the subspaces spanned by the second fundamental form, form a vector subbundle of the normal bundle of low rank which is nonparallel in the normal connection. We also characterize flat submanifolds with flat normal bundle in Euclidean space satisfying the helix property.
On Commutativity and Strong Commutativity-Preserving Maps
Authors: Bell Howard E. , Daif Mohamad Nagy 
Published: December 2010

AbstractIf R is a ring and S ⊆ R, a mapping f:R —> R is called strong commutativity- preserving (scp) on S if [x, y] = [f(x),f(y)] for all x,y € S. We investigate commutativity in prime and semiprime rings admitting a derivation or an endomorphism which is scp on a nonzero right ideal.
Configurations de Particules et Espaces de Modules
Authors: Hurtubise J. C. 
Published: December 2010

RésuméCet article de survol est le résumé de la conférence Coxeter-James de l'auteur, prononcée à la réunion d'hiver 1993 de la Société Mathématique du Canada.La théorie de Morse décrit les liens entre la topologie d'une variété et la topologie des points critiques d'une fonction sur cette variété. La fonctionnelle d'énergie pour les applications d'une surface dans une variété, dont les points critiques seront des applications harmoniques et parfois holomorphes, et la fonctionnelle de Yang-Mills pour des connections sur une variété de dimension quatre sont deux cas en dimension infinie pour lesquels la théorie de Morse ne tient pas. Néanmois, dans les deux cas, on peut récupérer une quantité étonnante d'information, pourvu qu'on stabilise par rapport à un degré ou une charge qui sont des données du problème. Les preuves recyclent des résultats de la théorie de l'homotopie des années '70, et les combinent à des idées de géométrie complexe pour donner de jolis modèles des espaces en cause en termes de "particules". Nous espérons donner un survol général et accessible des idées utilisées.
Characters and Point Evaluations
Authors: Ransford T. J. 
Published: December 2010

AbstractWe give a simple proof that, if X is a Lindelöf topological space, and A is an algebra of continuous real-valued functions on X which is inverse-closed, local and z-regular, then every character on A is a point evaluation. We also give a number of examples to illustrate both the applications of this theorem and its limitations.
α-Derivations
Authors: Redondo María Julia , Solotar Andrea 
Published: December 2010

AbstractLet A be a commutative k-algebra with 1. We present a characterization of α-derivations, for α: A →> A a morphism of algebras, using α-Taylor series. When S = C[x,x-1,ξ] and α(x) = qx, α(ξ) = qξ, we compare the q-de Rham cohomology of the C-algebra S with the Hochschild homology of Dq, the algebra of q-difference operators on C[x,x-1], for q ∊ C, q ≠ 0,1.
La formule de Cauchy sur la longueur d’une courbe
Authors: Ayari S. , Dubuc S. 
Published: December 2010

RésuméPour toute courbe rectifiable du plan, nous démontrons la formule de Cauchy relative à sa longueur. La formule est donnée sous deux formes: comme intégrale de la variation totale des projections de la courbe dans les diverses directions et comme intégrale double du nombre de rencontres de la courbe avec une droite quelconque du plan.
On Arithmetic Means of Sequences Generated by a Periodic Function
Authors: Fiorito Giovanni 
Published: December 2010

AbstractIn this paper we prove the convergence of arithmetic means of sequences generated by a periodic function φ(x), moreover if φ(x) satisfies a suitable symmetry condition, we prove that their limit is φ(0). Applications of previous results are given to study other means of sequences and the behaviour of a class of recursive series.
Topological Quantum Field Theory and Strong Shift Equivalence
Authors: Gilmer Patrick M. 
Published: December 2010

AbstractGiven a TQFT in dimensiond+ 1; and an infinite cyclic covering of a closed (d+ 1)-dimensional manifoldM, we define an invariant taking values in a strong shift equivalence class of matrices. The notion of strong shift equivalence originated in R. Williams’ work in symbolic dynamics. The Turaev-Viro module associated to a TQFT and an infinite cyclic covering is then given by the Jordan form of this matrix away from zero. This invariant is also defined if the boundary ofMhas anS1factor and the infinite cyclic cover of the boundary is standard. We define a variant of a TQFT associated to a finite groupGwhich has been studied by Quinn. In this way, we recover a link invariant due to D. Silver and S. Williams. We also obtain a variation on the Silver-Williams invariant, by using the TQFT associated toGin its unmodified form.
C*-Convexity and the Numerical Range
Authors: Magajna Bojan 
Published: December 2010

AbstractIf A is a prime C*-algebra, a ∈ A and λ is in the numerical range W(a) of a, then for each ε > 0 there exists an element h ∈ A such that . If λ is an extreme point of W(a), the same conclusion holds without the assumption that A is prime. Given any element a in a von Neumann algebra (or in a general C*-algebra) A, all normal elements in the weak* closure (the norm closure, respectively) of the C*-convex hull of a are characterized.
On the Number of Divisors of the Quadratic Form m2 + n2
Authors: Yu Gang 
Published: December 2010

AbstractFor an integer n, let d(n) denote the ordinary divisor function. This paper studies the asymptotic behavior of the sumIt is proved in the paper that, as x → ∞,where A1 and A2 are certain constants and ε is any fixed positive real number.The result corrects a false formula given in a paper of Gafurov concerning the same problem, and improves the error claimed by Gafurov.
Une classe d’hamiltoniens polynomiaux isochrones
Authors: Schuman Bertrand 
Published: December 2010

RésuméSoit un hamiltonien isochrone du plan . On met en évidence une classe d’hamiltoniens isochrones qui sont des perturbations polynomiales de H0. On obtient alors une condition nécessaire d’isochronisme, et un critère de choix pour les hamiltoniens isochrones. On voit ce résultat comme étant une généralisation du caractère isochrone des perturbations hamiltoniennes homogènes considérées dans [L], [P], [S].
Very Ample Linear Systems on Blowings-Up at General Points of Projective Spaces
Authors: Coppens Marc 
Published: December 2010

AbstractLet Pn be the n-dimensional projective space over some algebraically closed field k of characteristic 0. For an integer t ≥ 3 consider the invertible sheaf O(t) on Pn (Serre twist of the structure sheaf). Let , the dimension of the space of global sections of O(t), and let k be an integer satisfying 0 < k ≤ N − (2n + 2). Let P1,…,Pk be general points on Pn and let π : X → Pn be the blowing-up of Pn at those points. Let Ei = π−1(Pi) with 1 ≤ i ≤ k be the exceptional divisor. Then M = π*(O(t)) ⊗ OX(−E1 — … — Ek) is a very ample invertible sheaf on X.
Obstruction à la linéarisation des champs de vecteurs polynomiaux
Authors: Cresson Jacky 
Published: December 2010

RésuméOn explicite une classe de champ de vecteurs polynomiaux non analytiquement lin éarisables à l'aide de la correction introduite par Écalle-Vallet. Notamment, on étend des résultats de Schuman sur la trivialit é des hamiltoniens homogàenes isochrones.
Tracially Quasidiagonal Extensions
Authors: Lin Huaxin 
Published: December 2010

AbstractIt is known that a unital simple C*-algebra A with tracial topological rank zero has real rank zero. We show in this note that, in general, there are unital C*-algebras with tracial topological rank zero that have real rank other than zero.Let 0 → J → E → A → 0 be a short exact sequence of C*-algebras. Suppose that J and A have tracial topological rank zero. It is known that E has tracial topological rank zero as a C*-algebra if and only if E is tracially quasidiagonal as an extension. We present an example of a tracially quasidiagonal extension which is not quasidiagonal.
Congruence Class Sizes in Finite Sectionally Complemented Lattices
Authors: Grätzer G. , Schmidt E. T. 
Published: December 2010

AbstractThe congruences of a finite sectionally complemented lattice L are not necessarily uniform (any two congruence classes of a congruence are of the same size). To measure how far a congruence Θ of L is from being uniform, we introduce Spec Θ, the spectrum of Θ, the family of cardinalities of the congruence classes of Θ. A typical result of this paper characterizes the spectrum S = (mj | j < n) of a nontrivial congruence Θ with the following two properties:
Ramification des séries formelles
Authors: Laubie François 
Published: December 2010

AbstractLet p be a prime number. Let k be a finite field of characteristic p. The subset X + X2k[[X]] of the ring k[[X]] is a group under the substitution law ○ sometimes called the Nottingham group of k, it is denoted by Rk. The ramification of one series γ ∈ Rk is caracterized by its lower ramification numbers: , as well as its upper ramification numbers:By Sen's theorem, the um(γ) are integers. In this paper, we determine the sequences of integers (um) for which there exists γ ∈ Rk such that um(γ) = um for all integer m & 0.
Continuous Adjacency Preserving Maps on Real Matrices
Authors: Rodman Leiba , Šemrl Peter , Sourour Ahmed R. 
Published: December 2010

AbstractIt is proved that every adjacency preserving continuous map on the vector space of real matrices of fixed size, is either a bijective affine tranformation of the form A ⟼ PAQ + R, possibly followed by the transposition if the matrices are of square size, or its range is contained in a linear subspace consisting of matrices of rank at most one translated by some matrix R. The result extends previously known theorems where the map was assumed to be also injective.
Vector Fields and the Cohomology Ring of Toric Varieties
Authors: Kaveh Kiumars 
Published: December 2010

AbstractLetXbe a smooth complex projective variety with a holomorphic vector field with isolated zero setZ. From the results of Carrell and Lieberman there exists a filtrationF0⊂F1⊂ · · · ofA(Z), the ring of ℂ-valued functions onZ, such thatas graded algebras. In this note, for a smooth projective toric variety and a vector field generated by the action of a 1-parameter subgroup of the torus, we work out this filtration. Our main result is an explicit connection between this filtration and the polytope algebra ofX.
Non Abelian Twisted Reidemeister Torsion for Fibered Knots
Authors: Dubois Jérôme 
Published: December 2010

AbstractIn this article, we give an explicit formula to compute the non abelian twisted sign-determined Reidemeister torsion of the exterior of a fibered knot in terms of its monodromy. As an application, we give explicit formulae for the non abelian Reidemeister torsion of torus knots and of the figure eight knot.
Unimodular Roots of Special Littlewood Polynomials
Authors: Mercer Idris David 
Published: December 2010

AbstractWe call α(z) = a0 + a1z + · · · + an–1zn–1 a Littlewood polynomial if aj = ±1 for all j. We call α(z) self-reciprocal if α(z) = zn–1α(1/z), and call α(z) skewsymmetric if n = 2m + 1 and am+j = (–1)jam–j for all j. It has been observed that Littlewood polynomials with particularly high minimum modulus on the unit circle in ℂ tend to be skewsymmetric. In this paper, we prove that a skewsymmetric Littlewood polynomial cannot have any zeros on the unit circle, as well as providing a new proof of the known result that a self-reciprocal Littlewood polynomial must have a zero on the unit circle.
A K3 Surface Associated With Certain Integral Matrices Having Integral Eigenvalues
Authors: van Luijk Ronald 
Published: December 2010

AbstractIn this article we will show that there are infinitely many symmetric, integral 3× 3 matrices, with zeros on the diagonal, whose eigenvalues are all integral. We will do this by proving that the rational points on a certain non-Kummer, singular K3 surface are dense. We will also compute the entire Néron–Severi group of this surface and find all low degree curves on it.
Artinian Local Cohomology Modules
Authors: Lorestani Keivan Borna , Sahandi Parviz , Yassemi Siamak 
Published: December 2010

AbstractLet R be a commutative Noetherian ring, α an ideal of R and M a finitely generated R-module. Let t be a non-negative integer. It is known that if the local cohomology module is finitely generated for all i < t, then is finitely generated. In this paper it is shown that if is Artinian for all i < t, then need not be Artinian, but it has a finitely generated submodule N such that /N is Artinian.
Developing a theory of sport-based entrepreneurship
Authors: Ratten Vanessa 
Published: December 2010

AbstractEntrepreneurship is an integral part of sport but less is known about how different types of entrepreneurship facilitate innovation. The aim of this paper is to develop a theory of sports-based entrepreneurship that incorporates different sub-categories of entrepreneurship such as social, technological and international. Specifically, the article connects the entrepreneurship and sport management literatures by proposing a theory of sport-based entrepreneurship, which can be used as a theoretical framework for future research. In addition, the paper provides a unique insight for sports practitioners and public policy planners wanting to focus on entrepreneurial ways to manage sport-based organizations.
A model for improving board performance: The case of a national sport organisation
Authors: Ferkins Lesley , Mcdonald Gael , Shilbury David 
Published: December 2010

AbstractThe transition of many sport organisations from being predominantly volunteer-administered and anchored in an amateur ethos to professionally managed entities has created unique challenges for the governance of sport. This paper provides a contribution to the governance literature through the presentation of a situational case where a four-stage model, drawn from an action research approach, has been used for developing a board's strategic capability and subsequent improvement in organisational performance. Action research is founded on the premise that change and research are not mutually exclusive and that dual foci on improving practice and developing theory are possible (Coghlan & Brannick, 2001). Utilising a national sport organisation (NSO) in New Zealand the study developed and tested a structured model for improving board functioning and, specifically, strategic contribution. While the case to which the model has been applied is an NSO, the model and the subsequent reflections have value for non-profit as well as commercial entities particularly with regard to a greater understanding of the mechanisms associated with balancing the performance and conformance roles of the board.
Selective Artificial Receptors Based on Micropatterned Surface‐Imprinted Polymers for Label‐Free Detection of Proteins by SPR Imaging
Authors: Lautner Gergely , Kaev Jevgeni , Reut Jekaterina , Öpik Andres , Rappich Jörg , Syritski Vitali , Gyurcsányi Róbert E. 
Published: December 2010

AbstractA novel concept to generate micropatterned surface‐imprinted polymers (SIPs) for protein recognition by using standard photolithographic technology is introduced. Avidin‐imprinted poly(3,4‐ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) conducting polymer microbands are prepared directly on surface plasmon resonance (SPR) chips, which enable convenient label‐free monitoring of the binding events. The novel surface‐imprinted microstructures bind avidin, the template protein, with dissociation constants in the submicromolar range (125 nM). The SIPs have an avidin binding capacity approximately one order of magnitude higher than the corresponding nonimprinted polymers and are able to discriminate among functional homologues of avidin, i.e., neutravidin, extravidin, and streptavidin.
Adrenarche in comparative perspective
Authors: Campbell Benjamin 
Published: December 2010

AbstractObjectives: To addresses the hypothesis that human adrenarche is associated with extended juvenile brain development by comparing the timing of adrenal androgen production, brain development and lactation in a larger comparative mammalian context.Methods: Findings from published literature are used to compare the developmental timing of adrenal androgens, brain glucose utilization and lactation in rats, rhesus macaques and humans.Results: Comparison of the timing of androstenedione and progesterone production with developmental patterns of cortical glucose utilization and the timing of lactation in laboratory rats suggest that the rise and fall of adrenal hormone production centered on weaning plays a role in synaptogenesis during lactation as well as post weaning synaptic pruning. Comparison of the timing of cortical glucose utilization, DHEAS production and weaning in rhesus macaques also suggests that postnatally elevated levels of DHEAS may be related to patterns of synaptic formation and pruning centered on weaning. In contrast among humans, peak cortical glucose utilization occurs well after weaning and the rise in adrenal androgen production coincides with declining cortical glucose utilization with the onset of the juvenile stage.Conclusions: Compared to rats and macaque, in humans the energetic demands of brain development and increased production of adrenal androgens are divorced from the timing of lactation, while the timing of adrenarche and brain development are still associated. Thus the neuroprotective effects of DHEAS may protect synaptic plasticity in metabolically active parts of the brain starting approximately at the age of 7, promoting prolonged development of the human prefrontal cortex. Am. J. Hum. Biol., 2011. © 2010 Wiley‐Liss, Inc.
Comparative genetic approaches to the evolution of human brain and behavior
Authors: Vallender Eric J. 
Published: December 2010

AbstractWith advances in genomic technologies, the amount of genetic data available to scientists today is vast. Genomes are now available or planned for 14 different primate species and complete resequencing of numerous human individuals from numerous populations is underway. Moreover, high‐throughput deep sequencing is quickly making whole genome efforts within the reach of single laboratories allowing for unprecedented studies. Comparative genetic approaches to the identification of the underlying basis of human brain, behavior, and cognitive ability are moving to the forefront. Two approaches predominate: inter‐species divergence comparisons and intra‐species polymorphism studies. These methodological differences are useful for different time scales of evolution and necessarily focus on different evolutionary events in the history of primate and hominin evolution. Inter‐species divergence is more useful in studying large scale primate, or hominoid, evolution whereas intra‐species polymorphism can be more illuminating of recent hominin evolution. These differences in methodological utility also extend to studies of differing genetic substrates; current divergence studies focus primarily on protein evolution whereas polymorphism studies are substrate ambivalent. Some of the issues inherent in these studies can be ameliorated by current sequencing capabilities whereas others remain intractable. New avenues are also being opened that allow for the incorporation of novel substrates and approaches. In the post‐genomic era, the study of human evolution, specifically as it relates to the brain, is becoming more complete focusing increasingly on the totality of the system and better conceptualizing the entirety of the genetic changes that have lead to the human phenotype today. Am. J. Hum. Biol., 2011. © 2010 Wiley‐Liss, Inc.
Effect of boric acid and heat treatment for the formation of poly(vinyl alcohol)/iodine complex films iodinated at solution before casting
Authors: Shin Eun Joo , Lyoo Won Seok , Lee Yang Hun 
Published: December 2010

AbstractThis study examined the role of boric acid and the effect of heat treatment on PVA‐iodine polarizing films prepared in the solution state before casting (IBC) of PVA/iodine/boric acid films. The films were prepared by casting aqueous solutions of 10 wt % poly(vinyl alcohol) (PVA) containing boric acid with 0, 0.1, 0.3, and 0.5 mol/l of I2/KI aqueous solution, and I2/KI(1 : 2) with 5 wt % of PVA. The effect of boric acid and heat treatment on the durability of the IBC PVA polarizing sheet films was investigated by UV–vis absorption spectroscopy. Boric acid was found to be essential for the complex formation in PVA/iodine solutions at relatively low I2/KI concentrations and high temperatures. The strength of the complex peak at ∼ 600 nm in UV–vis absorption spectra increased with increasing boric acid concentration. With increasing heating temperature over 90°C the intensity of the peak at 600 nm corresponding to the complex decreased due to the evaporation of I2 decomposed from I5−, but the peak at 355 nm corresponding to free I2·I3− was remained unchanged. From heat treatment at 150°C, the intensity of the peak at 600 nm decreased but the intensity of the complex peak (600 nm) of the sample with 0.5 mol/l boric acid was unaffected. The transmittance and degree of polarization for the films increased and decreased with increasing heat treatment time under heat and a humid atmosphere, respectively. However, this tendency decreased with increasing boric acid concentration and heat treatment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Women's experiential journey toward voluntary childlessness: An interpretative phenomenological analysis
Authors: Shaw Rachel Louise 
Published: December 2010

AbstractVoluntary childlessness is a relatively novel yet growing phenomenon. This idiographic study explored three women's experiential journeys toward voluntary childlessness. Semi‐structured interviews were carried out and analysed using Interpretative Phenomenological Analysis. Themes identified were: Owning the choice to be childless, social expectations, and models of mothering. Despite defining ‘voluntary childlessness’ as an unequivocal decision, the women's experiential accounts revealed an intrinsic fluidity in their journeys toward childlessness. Factors including beliefs in equality, independence and career aspirations competed with constructs of mothering/motherhood, partnership and choice to create a complex tapestry of contributory factors in these women's childlessness. The findings question the notion of choice and particularly women's ownership of that choice. The journeys toward childlessness these women shared reveal a synthesis of agentic decision‐making, personal histories and challenging lifestyle choices bound up within an existential need to be a woman. More research is needed to determine the place of voluntary childlessness within society. Copyright © 2010 John Wiley & Sons, Ltd.