bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conditional measure and flip invariance of Bowen-Margulis and harmonic measures on manifolds of negative curvature
Authors: Yue Chengbo 
Published: September 2008

AbstractKifer and Ledrappier have asked whether the harmonic measures {νx} on manifolds of negative curvature are equivalent to the conditional measures of the harmonic measure v of the geodesic flow associated with the fibration {SxM}x∈M. We settle this question with a rigidity result. We also clear up the same problem concerning the Patterson-Sullivan measure and the Bowen–Margulis measure.
Successive derivatives of a first return map, application to the study of quadratic vector fields
Authors: Francoise J. P. 
Published: September 2008

AbstractWe provide an algorithm to compute the first non-zero derivative of the return map r ↦ L(r, ε) of a planar vector field which is a polynomial perturbation of . It yields a new method for finding the centre conditions in the case of a homogeneous perturbative part.
Ergodic transformations conjugate to their inverses by involutions
Authors: Goodson Geoffrey R. , del Junco Andrés , Lemańczyk Mariusz , Rudolph Daniel J. 
Published: September 2008

AbstractLetTbe an ergodic automorphism defined on a standard Borel probability space for whichTandT−1are isomorphic. We investigate the form of the conjugating automorphism. It is well known that ifTis ergodic having a discrete spectrum andSis the conjugation betweenTandT−1, i.e.SsatisfiesTS=ST−1thenS2=Ithe identity automorphism. We show that this result remains true under the weaker assumption thatThas a simple spectrum. IfThas the weak closure property and is isomorphic to its inverse, it is shown that the conjugationSsatisfiesS4=I. Finally, we construct an example to show that the conjugation need not be an involution in this case. The example we construct, in addition to having the weak closure property, is of rank two, rigid and simple for all orders with a singular spectrum of multiplicity equal to two.
Topological Wiener–Wintner ergodic theorems and a randomL2ergodic theorem
Authors: Walters Peter 
Published: September 2008

AbstractWe give some topological ergodic theorems inspired by theWiener-Wintnerergodic theorem. These theorems are used to give results for uniquely ergodic transformations and to study unique equilibrium states for shift maps. These latter results give randomL2ergodic theorems for a finite set of commuting measure-preserving transformations.
The strong sweeping out property for lacunary sequences, Riemann sums, convolution powers, and related matters
Authors: Akcoglu Mustafa , Bellow Alexandra , Jones Roger L. , Losert Viktor , Reinhold-Larsson Karin , Wierdl Máté 
Published: September 2008

AbstractIn this paper we establish conditions on a sequence of operators which imply divergence. In fact, we give conditions which imply that we can find a set B of measure as close to zero as we like, but such that the operators applied to the characteristic function of this set have a lim sup equal to 1 and a lim inf equal to 0 a.e. (strong sweeping out). The results include the fact that ergodic averages along lacunary sequences, certain convolution powers, and the Riemann sums considered by Rudin are all strong sweeping out. One of the criteria for strong sweeping out involves a condition on the Fourier transform of the sequence of measures, which is often easily checked. The second criterion for strong sweeping out involves showing that a sequence of numbers satisfies a property similar to the conclusion of Kronecker's lemma on sequences linearly independent over the rationals.
Systèmes dynamiques gaussiens d'entropie nulle, lâchement et non lâchement Bernoulli
Authors: De La Rue Thierry 
Published: September 2008

AbstractWe construct two real Gaussian dynamical systems of zero entropy; the first one is not loosely Bernoulli, and the second is a loosely Bernoulli Gaussian-Kronecker system. To get loose-Bernoullicity for the second system, we prove and use a property of planar Brownian motion on [0, 1]: we can recover the whole trajectory knowing only some angles formed by the motion.
A non-transverse homoclinic orbit to a saddle-node equilibrium
Authors: Champneys Alan R. , Härterich Jörg , Sandstede Björn 
Published: September 2008

AbstractA homoclinic orbit is considered for which the center-stable and center-unstable manifolds of a saddle-node equilibrium have a quadratic tangency. This bifurcation is of codimension two and leads generically to the creation of a bifurcation curve defining two independent transverse homoclinic orbits to a saddle-node. This latter case was shown by Shilnikov to imply shift dynamics. It is proved here that in a large open parameter region of the codimension-two singularity, the dynamics are completely described by a perturbation of the Hénon-map giving strange attractors, Newhouse sinks and the creation of the shift dynamics. In addition, an example system admitting this bifurcation is constructed and numerical computations are performed on it.
Stochastic stability of Bernoulli toral linked twist maps of finite and infinite entropy
Authors: Nicol Matthew 
Published: September 2008

AbstractWe construct linked twist maps of the two-dimensional torus which are Bernoulli and possess infinite entropy. Inparticular, we construct a Bernoulli toral linked twist map B* of infinite entropy which has smooth, absolutely continuous local (un)stable manifolds and positive Lyapunov exponents defined almost everywhere. This map is continuous at each point save those on two line segments.B* is shown to be stochastically stable under the following random perturbation: apply the map to a point p and then jump (all points move the same distance and in the same direction) according to a B-process (not necessarily an independent process) such that the expected distance moved is equal to r. Stochastic stability means that given α > 0 if r > 0 is sufficiently small then the perturbed and unperturbed systems are α-congruent. We prove a similar stability result for B* under a perturbation in which the random jump described above is distributed according to a general stochastic process. These stability results are also shown to hold (in a slightly modified form) for a general class of finite-entropy toral linked twist maps under the same perturbations.
Accumulation theorems for quadratic polynomials
Authors: Sørensen Dan Erik Krarup 
Published: September 2008

AbstractWe consider the one-parameter family of quadratic polynomials:i.e. monic centered quadratic polynomials with an indifferent fixed point αtand prefixed point −αt. LetAt, be any one of the sets {0, ±αt}, {±αt}, {0, αt}, or {0, −αt}. Then we prove that for quadratic Julia sets corresponding to aGδ-dense subset ofthere is an explicitly given external ray accumulating onAt. In the caseAt= {±αt} the theorem is known as theDouady accumulation theorem.Corollaries are the non-local connectivity of these Julia sets and the fact that all such Julia sets contain a Cremer point. Existence of non-locally connected quadratic Julia sets of Hausdorff dimension two is derived by using a recent result of Shishikura. By tuning, the results hold on the boundary of any hyperbolic component of the Mandelbrot set.Finally, we concentrate on quadratic Cremer point polynomials. Here we prove that any ray accumulating on two symmetrical points of the Julia set must accumulate the origin. As a consequence, the denseGδsets arising from the first two possible choices ofAtare the same. We also prove that, if two distinct rays accumulate both to two distinct points, then the rays must accumulate on a common continuum joining the two points. This supports the conjecture that αtand –αtmay be joined by an arc in the Julia set.
Generalized Fredholm determinants and Selberg zeta functions for Axiom A dynamical systems
Authors: Rugh Hans Henrik 
Published: September 2008

AbstractWe consider a generalized Fredholm determinant d(z) and a generalized Selberg zeta function ζ(ω)−1 for Axiom A diffeomorphisms of a surface and Axiom A flows on three-dimensional manifolds, respectively. We show that d(z) and ζ(ω)−1 extend to entire functions in the complex plane. That the functions are entire and not only meromorphic is proved by a new method, identifying removable singularities by a change of Markov partitions.
A weakly mixing upside-down tower of isometric extensions
Authors: Glasner S. , Weiss B. 
Published: September 2008

AbstractOn the infinite torus X =, using a category argument, we produce a large family of homeomorphisms such that for every elementSin this family the flow (S, X) is weakly mixing and strictly ergodic. Moreover, writing Xn={n, n+ 1…}and lettingΠn, m, forn<m, be the projection ofXnonXm,Sinduces for everyn, a homeomorphism ofXnand the extensionsare isometric. We also show that, for everySin this family, (S, X) is disjoint from every purely weakly mixing flow.
Theory for high-order bounds in functional principal components analysis
Authors: HALL PETER , HOSSEINI–NASAB MOHAMMAD 
Published: September 2008

AbstractFunctional data analysis, or FDA, is a relatively new and rapidly growing area of statistics. A substantial part of the interest in the field derives from new types of data that are generated through the application of new technologies. Statistical methodologies, such as linear regression, which are effectively finite-dimensional in conventional statistical settings, become infinite-dimensional in the context of functional data. As a result, the convergence rates of estimators based on functional data can be relatively slow, and so there is substantial interest in methods for dimension reduction, such as principal components analysis (PCA). However, although the statistical development of PCA for FDA has been underway for approximately two decades, relatively high-order theoretical arguments have been largely absent. This makes it difficult to assess the impact that, for example, eigenvalue spacings have on properties of eigenvalue estimators, or to develop concise first-order limit theory for linear functional regression. This paper shows how to overcome these hurdles. It develops rigorous arguments that underpin stochastic expansions of estimators of eigenvalues and eigenfunctions, and shows how to use them to answer statistical questions. The theory is based on arguments from operator theory, made more challenging by the requirement of statisticians that closeness of functions be measured in theL∞, rather thanL2, metric. The statistical implications of the properties we develop have been discussed elsewhere, but the theoretical arguments that lie behind them have not been presented before.
The first-order genus of a knot
Authors: HORN PETER D. 
Published: September 2008

AbstractWe introduce a geometric invariant of knots in S3, called the first-order genus, that is derived from certain 2-complexes called gropes, and we show it is computable for many examples. While computing this invariant, we draw some interesting conclusions about the structure of a general Seifert surface for some knots.
On the Berstein–Svarc theorem in dimension 2
Authors: DRANISHNIKOV ALEXANDER N. , RUDYAK YULI B. 
Published: September 2008

AbstractWe prove that for any group π with cohomological dimension at least n the nth power of the Berstein class of π is nontrivial. This allows us to prove the following Berstein–Svarc theorem for all n:Theorem. For a connected complex X with dim X = cat X = n, we have$\ber_X^n$ ≠ 0 where$\ber_X$is the Berstein class of X.Previously it was known for n ≥ 3.We also prove that, for every map f: M → N of degree ±1 of closed orientable manifolds, the fundamental group of N is free provided that the fundamental group of M is.
On the relation between the WRT invariant and the Hennings invariant
Authors: CHEN QI , KUPPUM SRIKANTH , SRINIVASAN PARTHASARATHY 
Published: September 2008

AbstractThe purpose of this paper is to provide a simple relation between the Witten–Reshetikhin-TuraevSO(3) invariant and the Hennings invariant associated to quantum$\fsl2$.
Scientific design rationale
Authors: Haynes Steven R. , Bach Paula M. , Carroll John M. 
Published: September 2008

AbstractDesign rationale should be regarded both as a tool for the practice of design, and as a method to enable thescienceof design. Design rationale answers questions about why a given design takes the form that it does. Answers to thesewhyquestions represent a significant portion of the knowledge generated from design research. This knowledge, along with that from empirical studies of designs in use, contributes to what Simon calledthe sciences of the artificial. Most research on the nature and use of design rationale has been analytic or theoretical. In this article, we describe an empirical study of the roles that design rationale can play in the conduct of design research. We report results from an interview study with 16 design researchers investigating how they construe and carry out design as research. The results include an integrated framework of the affordances design rationale can contribute to design research. The framework and supporting qualitative data provide insight into how design rationale might be more effectively leveraged as a first-class methodology for research into the creation and use of artifacts.
Antecedence and consequence in design rationale systems
Authors: Agouridas Vassilis , Simons Peter 
Published: September 2008

AbstractIdentification of latent or unarticulated customer and other stakeholder needs has been a significant barrier to improving the efficiency and effectiveness of the front-end phase of new product development processes. In-depth determination of stakeholder needs entails analysis of their intentions; the overall aim of the work reported in this article is to establish a framework of intentional analysis, and its associated methods and techniques for improving traceability of design practice during the early phases of the design process. The specific aim of this article is to present a conceptual framework for design rationale systems. The framework built upon the cross-fertilization of approaches and methods drawn from systems engineering and philosophy, focussing on the notions of antecedence and consequence. It was developed in the course of tackling design problems originating in industrial contexts. The methods developed were thus evaluated, updated, and refined in real applications. Two application cases are described that have been drawn from the aerospace and power sectors, respectively. The applications showed that the framework's central antecedent/consequent scheme provides a cell from which to develop either a history of actual successive changes, or a tree of alternative possible projected designs.
Seed development in peas: knowing your three ‘r's’ (or four, or five)
Authors: Wang T. L. , Hedley C. L. 
Published: September 2008

AbstractThe value of the garden pea (Pisum sativum) both as an experimental tool and food crop has led to an accumulated wealth of genetic variation. This paper describes how some of the variation may be harnessed for studying seed development. One can identify genotypic differences for maternal, embryonic and cellular components and the interaction between them. The impact of these components on processes such as cell division, partitioning and the deposition of storage products can then be assessed by utilizing new techniques such as immunocytochemistry andin situhybridization.Therugosusloci, which induce wrinkling of the seed, are examples of how major genes can be exploited to dissect seed development. Alleles at one of these loci,r, have been defined at both the molecular and biochemical levels. A much clearer picture can now be drawn of the pleiotropic nature of the genes, from their effects on starch composition to those on cellular development, which has implications for seed development in many species. Therugosusloci are the only ones known to affect seed development in peas. By analogy with cereal seeds, however, one would anticipate other mutants in the starch pathway which also affect the shape of the seed. Here, we report the induction of newrugosus-like mutants, compare them to starch mutants in other species and examine the ways in which they may help our understanding of starch biosynthesis and the regulation of seed development.
Stimulation of germination of dormant oat (Avena sativa L.) seeds by ethanol and other alcohols
Authors: Corbineau F. , Gouble B. , Lecat S. , Côme D. 
Published: September 2008

AbstractDormant dehusked Avena sativa L. (cv. Moyencourt) caryopses germinated easily at 10°C, but their germination was poor at 25 and 30°C. Ethanol overcame their dormancy and allowed germination at the last two temperatures when given continuously at concentrations ranging from 50 to 200 mm, or at higher concentrations at the beginning of imbibition. Ethanol also promoted germination in hypoxia. Other alcohols which were good substrates for alcohol dehydrogenase (ADH: EC 1.1.1.1), such as butanol-1, propanol-1 and 2-propen-1-ol, had the same stimulatory effect as ethanol, whereas alcohols which could not be oxidized by ADH (propanol-2 and methanol) did not improve germination. Salicylhydroxamic acid (SHAM) did not alter the stimulation of germination induced by ethanol, but 4-methylpyrazole (4-MP, an inhibitor of ADH) completely abolished this stimulation. The improvement of germination by alcohols which were good substrates for ADH was always associated with an increase in oxygen uptake by caryopses, whereas alcohols which were not ADH substrates did not enhance respiration. The stimulation of oxygen uptake induced by ethanol resulted in a decrease in CO2/O2 ratio and was suppressed by 4-MP, but ATP level in embryos was not modified until after the germination of caryopses. All the results obtained seem to demonstrate that the stimulatory action of ethanol on germination of dormant oat caryopses requires its metabolism through ADH and involves an activation of glycolysis and the Krebs cycle.
Protein synthesis during osmopriming of leek (Allium porrum L.) seeds
Authors: Davison P. A. , Bray C. M. 
Published: September 2008

AbstractAn osmotic priming treatment of 14 days in a −1.0 MPa polyethylene glycol solution improves the germination performance of a highvigour seed lot of leek (Allium porrum L., cv. Verina). Using in vivo pulse-labelling, two-dimensional polyacrylamide gel electrophoresis and fluorography, five polypeptides were found to be synthesized in embryonic tissue at 14 days of priming that were not present at 4 days of germination without prior priming. These polypeptides were still synthesized at 6 h of germination following priming. This time point lies in the 6–12 h lag phase in protein synthesis previously observed in leek embryo tissue during germination of primed seeds where there is little increase in the rate of synthesis over that seen at the end of priming. None of the polypeptides was synthesized at 2 days of germination after priming, a period of seedling growth. The five polypeptides appear to be specifically associated with the priming period. Two additional polypeptides were found in leek embryos that were synthesized at higher levels at the end of priming than during germination alone. These continued to be synthesized, at lower levels in leek embryo tissue upon germination after priming. Several polypeptides were identified in leek endosperm tissue which were synthesized at higher levels during priming than during germination and also two polypeptides whose synthesis appeared to be specific to germination.
Endo-β-mannanase activity and reserve mobilization in excised endosperms of fenugreek is affected by volume of incubation and abscisic acid
Authors: Malek L. , Bewley J. D. 
Published: September 2008

AbstractGalactomannan hydrolysis in isolated endosperms of fenugreek seeds is promoted by the presence of the embryo. Incubation in a large volume in the absence of the axis also results in endosperm mobilization and an increase in endo-β-mannanase activity. This is prevented when endosperms are incubated in a small volume, or when abscisic acid is present in the large volume. Fenugreek endosperms contain abscisic acid which is present in greater concentrations when these tissues have been incubated in a small volume rather than in a large volume. Antibodies prepared against purified tomato endo-β-mannanase detect the fenugreek enzyme on Western blots. Endosperms contain equal amounts of this enzyme whether they are incubated in a large volume, or in a small volume, or in the presence of abscisic acid. Thus, increased enzymic activity may not be related to increased synthesis, but rather to activation or release from the cells into the galactomannan-containing cell walls.
Inhibition of germination inAmaranthus albusseeds by prolonged irradiation: a physiological basis
Authors: Taylorson R. B. 
Published: September 2008

AbstractAmaranthus albusL. seeds able to germinate in darkness can be prevented from germinating by prolonged irradiation with incandescent light (CIL). The germination in darkness is controlled by pre-existent Pfr. Allowing the seeds to remain in darkness for about 16 h allows an escape from the inhibition by CIL, about comparable with the time required to escape from pre-existent Pfrcontrol. By examining escape from low fluence far-red (FR), it was found that no escape occurred in CIL. It was concluded that the mode of action of CIL in inhibitingA. albusseed germination involved prevention of the action of the pre-existent Pfrand a subsequent dormancy which does not allow a response to the Pfrgenerated by the incandescent light. Other actions of CIL were found but were considered less likely as causative for the inhibition of germination. One was a direct inhibition of radicle elongation and another involved prevention of an increased responsiveness to Pfrinduced by treatment at 40°C.
The effects of the parent environment on seed germinability
Authors: Fenner M. 
Published: September 2008

AbstractThe growing conditions of a parent plant may affect the degree of dormancy of its seeds. This has been demonstrated in numerous species, both wild and cultivated. The evidence comes from field observations and controlled experiments. A survey of the literature shows that some well defined patterns emerge, with certain environmental factors tending to have similar effects over a wide range of species. Lower dormancy (i.e., increased germinability) is generally associated with the following environmental conditions during seed development: high temperatures, short days, red light, drought and high nitrogen levels. The effects are probably the result of changes in the quantity, mobility or activity of growth substances such as abscisic acid. The ecological implications of the phenomenon are briefly discussed.
Morphological stages and storage protein accumulation in developing alfalfa (Medicago sativa L.) seeds
Authors: Xu N. , Coulter K. M. , Krochko J. E. , Bewley J. D. 
Published: September 2008

AbstractIdentification of discrete stages during embryogenesis is important for the consistent and repeatable selection of seeds having similar developmental characteristics. A timetable for staging developing seeds of alfalfa (Medicago sativa L.) has been developed. Morphological characteristics, fresh and dry weights, SDSpolyacrylamide gel electrophoretic protein patterns and total protein content were recorded at various times between fertilization and 36 d after pollination (maturity), stages I–IX. A full complement of storage proteins (2S, 7S, 11S) is synthesized in both developing cotyledons and radicles. Low-salt soluble (S1) and high-salt soluble (S2) storage proteins first appear during embryo elongation. The proportional amounts of some S1 storage proteins change during alfalfa seed development. Markers are thus provided as uniform reference points for staging from the time of anthesis to seed shedding.