bluuebunny/crossref_metadata_2025 huggingface dataset:
Does individual variation in fruit profitability override color differences in avian choice of red or white Ilex serrata fruits?
Authors: Tsujita Kaori , Sakai Shinjiro , Kikuzawa Kihachiro
Published: July 2007

Although avian color preferences have been studied and documented in controlled experiments, they have not been demonstrated under natural conditions in most cases. We hypothesized that avian fruit choice reflects intraspecific variation in fruit characteristics other than color, rather than fruit color differences. By planting one Ilex serrata Thunb. (red form) and one I. serrata forma leucocarpa Beissner (white form), which produce red and white fruits, respectively, at each of five points, we examined the proportion of fruits removed per tree and fruit choice by three avian species based on fruit color and other fruit characteristics. The proportion of fruits removed increased with pulpy sugar concentration and fruit diameter, but it did not differ between fruit colors. The main foragers, resident brown‐eared bulbuls Hypsypetes amaurotis, consumed fruits regardless of color, but correspondingly to fruit removal, and appeared to base their fruit choice on pulpy sugar concentration and fruit diameter rather than on color. In contrast, the minor foragers, migrant Daurian redstarts Phoenicurus auroreus (Pallas) and Siberian bluechats Tarsiger cyanurus (Pallas), tended to choose red fruits and were possibly attracted by them. In conclusion, fruit removal per tree reflected individual variation in fruit profitability more strongly than differences in fruit color, even though the individual variation was not remarkable. The importance of color in fruit choice differed based on species, residency status, and major/minor foragers.
Chromatographic Analysis of the Reaction of Soy Flour with Formaldehyde and Phenol for Wood Adhesives
Authors: Lorenz Linda , Frihart Charles R. , Wescott James M.
Published: July 2007

The desire to make more biobased and lower‐cost bonded wood products has led to an interest in replacing some phenol and formaldehyde in wood adhesives with soybean flour. Improved knowledge of the soy protein properties is needed to relate resin chemistry to resin performance before and after wood bonding. To expose the soy protein's functional groups, it needs to be disrupted, with minimal hydrolysis, to maximize its incorporation into the final polymerized adhesive lattice. The best conditions for alkali soy protein disruption were to maintain the temperature below 100 °C and react the soy flour with sodium hydroxide at pH 9–12 for about 1 hour. A gel permeation chromatography procedure was optimized to determine conditions for selectively breaking down the high molecular weight soy protein fragments that contribute to high adhesive viscosity. This method and extraction data were used to evaluate the reaction of the disrupted soy flour protein with formaldehyde and phenol to provide a stable adhesive. The results were used to develop more economical adhesives that are ideally suited for the face section of oriented strandboard.
Liquid‐phase catalytic oxidation of unsaturated fatty acids
Authors: Noureddini H. , Kanabur M.
Published: July 2007

Liquid‐phase catalytic oxidation of oleic acid with hydrogen peroxide in the presence of various transition metal/metal oxide catalysts was studied in a batch autoclave reactor. Azelaic and pelargonic acids are the major reaction products. Tungsten and tantalum and their oxides in supported and unsupported forms were used as catalysts. Alumina pellets and Kieselguhr powder were used as supports for the catalysts. Tungsten, tantalum, molybdenum, zirconium, and niobium were also examined as catalysts. Tertiary butanol was used as solvent. Experimental results concluded that tungsten and tungstic oxide are more suitable catalysts in terms of their activity and selectivity. The rate of reaction observed in the case of supported catalysts appears to be comparable or superior to that of unsupported catalysts. In pure form, tungsten, tantalum, and molybdenum showed strong catalytic activity in the oxidation reaction; however, except for tantalum the other two were determined to be economically unfeasible. Zirconium and niobium showed very little catalytic activity. Based on the experimental observations, tungstic oxide supported on silica is the most suitable catalyst for the oxidation of oleic acid with 85% of the starting oleic acid converted to the oxidation products in 60 min of reaction with high selectivity for azelaic acid.
Stable isotope characterization of olive oils. I—Compositional and carbon‐13 profiles of fatty acids
Authors: Royer A. , Gerard C. , Naulet N. , Lees M. , Martin G. J.
Published: July 2007

Nearly 200 olive oils produced in the Mediterranean basin, mainly in Greece, during 4 yr from 1993 to 1996, were studied by gas chromatography (GC) and on‐line GC‐isotope ratio mass spectrometry (GC‐C‐IRMS). The composition of the oils in the more abundant fatty acids (C16:0, C16:1, C18:0, C18:1, C18:2, and C18:3) was obtained by GC after transesterification of the triglycerides into methyl esters. Using the hyphenated GC‐C‐IRMS technique, the 13C contents of the three most abundant acids, C16:0, C18:1, and C18:2, were measured with satisfactory accuracy. The results, analyzed in terms of geographical, temporal, and botanical factors, provide new criteria for the authentication of olive oils.
Comparison of attenuated total reflection infrared spectroscopy to capillary gas chromatography for trans fatty acid determination
Authors: Adam M. , Mossoba M. M. , Dawson T. , Chew M. , Wasserman S.
Published: July 2007

Gas chromatography (GC) has been a standard analytical tool in lipid chemistry. The rapid attenuated total reflection (ATR) infrared (IR) American Oil Chemists’ Society (AOCS) Recommended Practice (Cd 14d‐97) was compared to the capillary GC AOCS Recommended Practice (Ce 1f‐97) that was optimized to accurately determine total trans fatty acids on highly polar stationary phases. This comparative evaluation was validated in an independent laboratory. These procedures were used to quantitate the total trans fatty acid levels in partially hydrogenated vegetable oils, measured as neat (without solvent) triacylglycerols (TAG) by ATR and as fatty acid methyl ester (FAME) derivatives by capillary GC. Unlike FAME, TAG determination by ATR required no derivatization, but samples had to be melted prior to measurement. Five blind replicates for each of three accuracy standards and three test samples were analyzed by each technique. The GC and ATR determinations were in good agreement. Accuracy was generally high. The ratios of ATR mean trans values (reported as percentage of total TAG) to the true values (based on the amount of trielaidin added gravimetrically) were 0.89, 0.98, and 1.02 for accuracy standards having about 1, 10, and 40% trans levels. The corresponding GC values, determined as percentage of total FAME, were 0.98, 0.99 and 1.04. The ratios of mean trans values determined by these techniques were ATR/GC 0.85, 1.04, and 1.01 for test samples having trans levels of about 0.7, 8, and 38%, respectively. The optimized GC procedure also minimzed the expected low bias in trans values due to GC peak overlap found with the GC Official Method Ce 1c‐89. Satisfactory repeatability and reproducibility were obtained by both ATR and GC.
A reverse‐phase high‐performance liquid chromatographic method for analyzing complex mixtures of triglycerides. Application to the fat fraction of an aged cheese
Authors: Nájera A. I. , Perea S. , Barcina Y. , de Renobales M. , Barron L. J. R.
Published: July 2007

Analysis of complex mixtures of triglycerides that span a broad range of partition numbers can entail a number of difficulties. The present study was therefore intended to develop a method of reverse‐phase high‐performance liquid chromatography using a light scattering detector for analyzing such mixtures. Stationary phase type, mobile phase gradient, column temperature, and injection solvent were the factors used to develop the method. The method improved the selectivity of critical pairs of milk fat triglycerides, providing good resolution for 115 peaks with partition numbers of between 22 and 53. The use of tristearin as internal standard and the relative response factors for different partition number ranges made it possible to more accurately estimate the weight of the sample triglycerides.
Whose security? Deepening social conflict over ‘customary’ land in the shadow of land tenure reform in Malawi
Authors: Peters Pauline E. , Kambewa Daimon
Published: July 2007

Malawi, like other countries in Africa, has a new land policy designed to clarify and formalise customary tenure. The country is poor with a high population density, highly dependent on agriculture, and the research sites are matrilineal-matrilocal, and near urban centres. But the case raises issues relevant to land tenure reform elsewhere: the role of ‘traditional authorities’ or chiefsvis-à-visthe state and ‘community’; variability in types of ‘customary’ tenure; and deepening inequality within rural populations. Even before it is implemented, the pending land policy in Malawi is intensifying competition over land. We discuss this and the increase in rentals and sales; the effects of public debates about the new land policy; a new discourse about ‘original settlers’ and ‘strangers’; and political manoeuvring by chiefs.
Session 4: Mineral metabolism and body composition Iron status of breast-fed infants
Authors: Dewey Kathryn G. , Chaparro Camila M.
Published: July 2007

Fe deficiency is a common nutritional disorder during infancy, particularly in low-income countries. The Fe status of a breast-fed infant is strongly influenced by the body Fe content at birth, which is determined by factors that operate before birth (maternal Fe status before and during pregnancy; infant gestational age and birth weight) and at the time of delivery (the timing of umbilical cord clamping). Delaying the clamping of the umbilical cord for 2 min can increase body Fe content by approximately 33% (75 mg), and results in greater Fe stores at 6 months of age. After birth, male gender and a rapid rate of weight gain are associated with lower Fe status. During the first half of infancy dietary Fe requirements depend on Fe stores at birth. For an exclusively-breast-fed full-term normal-birth-weight infant with delayed umbilical cord clamping, whose mother had adequate Fe status during pregnancy, the Fe provided from stores and breast milk is sufficient for ≥6 months, but before this time higher-risk infants may become Fe deficient. Fe supplementation can be beneficial for high-risk infants, but can have adverse effects on growth and morbidity of Fe-replete infants. After 6 months most breast-fed infants will require complementary foods that are rich in Fe.
The functional Fučik spectrum has empty interior
Authors: Arias M. , Campos J. , Cuesta M. , Gossez J.-P.
Published: July 2007

We define a functional version of the Fučik spectrum for the Laplacian and we prove that this functional spectrum has empty interior.
Dynamics of a non-autonomous ratio-dependent predator—prey system
Authors: Fan Meng , Wang Qian , Zou Xingfu
Published: July 2007

We investigate a non-autonomous ratio-dependent predator–prey system, whose autonomous versions have been analysed by several authors. For the general non-autonomous case, we address such properties as positive invariance, permanence, non-persistence and the globally asymptotic stability for the system. For the periodic and almost-periodic cases, we obtain conditions for existence, uniqueness and stability of a positive periodic solution, and a positive almost-periodic solution, respectively.
Multiple boundary blow-up solutions for nonlinear elliptic equations
Authors: Aftalion Amandine , del Pino Manuel , Letelier René
Published: July 2007

We consider the problem Δu = λf(u) in Ω, u(x) tends to +∞ as x approaches ∂Ω. Here, Ω is a bounded smooth domain in RN, N ≥ 1 and λ is a positive parameter. In this paper, we are interested in analysing the role of the sign changes of the function f in the number of solutions of this problem. As a consequence of our main result, we find that if Ω is star-shaped and f behaves like f(u) = u(u−a)(u−1) with ½ < a < 1, then there is a solution bigger than 1 for all λ and there exists λ0 > 0 such that, for λ < λ0, there is no positive solution that crosses 1 and, for λ > λ0, at least two solutions that cross 1. The proof is based on a priori estimates, the construction of barriers and topological-degree arguments.
Gradient theory of phase transitions in composite media
Authors: Ansini Nadia , Braides Andrea , Chiadò Piat Valeria
Published: July 2007

We study the behaviour of non-convex functionals singularly perturbed by a possibly oscillating inhomogeneous gradient term, in the spirit of the gradient theory of phase transitions. We show that a limit problem giving a sharp interface, as the perturbation vanishes, always exists, but may be inhomogeneous or anisotropic. We specialize this study when the perturbation oscillates periodically, highlighting three types of regimes, depending on the frequency of the oscillations. In the two extreme cases, a separation of scales effect is described.
Structure of non-trivial non-negative solutions to singularly perturbed semilinear Dirichlet problems
Authors: Guo Zongming
Published: July 2007

The structure of non-trivial non-negative solutions to singularly perturbed semilinear Dirichlet problems of the form −ε2Δu = f(u) in Ω, u = 0 on ∂Ω, Ω ⊂ RN a bounded smooth domain, is studied as ε → 0+, for a class of nonlinearities f(u) satisfying f(0) = f(z1) = f(z2) = 0 with 0 < z1 < z2, f < 0 in (0, z1), f > 0 in (z1, z2) and . It is shown that there are many non-trivial non-negative solutions and they are spike-layer solutions. Moreover, the measure of each spike layer is estimated as ε → 0+. These results are applied to the study of the structure of positive solutions of the same problems with f changing sign many times in (0, ∞). Uniqueness of a large positive solution and many positive intermediate spike-layer solutions are obtained for ε sufficiently small.
Interior Hölder estimates for non-parametric surfaces of prescribed mean curvature
Authors: Liang Fei-Tsen
Published: July 2007

For a bounded solution to the mean curvature equation in Rn, we shall obtain its Hölder estimates, with exponent α, which are in linear proportion to the number obtained by dividing its global oscillation by the αth power of the distance of a point to the boundary of the domain after a suitable rescaling.
A decomposition of the (1 + β)-superprocess conditioned on survival
Authors: Etheridge A. M. , Williams D. R. E.
Published: July 2007

There is a large catalogue of decompositions of conditioned superprocesses in terms of an ‘immortal backbone’ or ‘skeleton’ along the branches of which mass is constantly immigrated. We add to this with a study of the (infinite-variance) (1 + β)-superprocess, conditioned on survival until some fixed time T. As one would expect, we see a Poisson number of immortal trees (conditioned on there being at least one), along which mass (conditioned to die before time T) is immigrated. However, here we see a new source of immigration. Not only is mass immigrated along the branches of the immortal trees, but also there is an extra burst of immigration whenever the immortal tree branches. Moreover, the rate of immigration along the branches is no longer deterministic. In the limit as T → ∞, the immortal trees degenerate to the Evans immortal particle and the immigration (of unconditioned mass) along the particle is dictated by a stable subordinator.
Qualitative analysis of a ratio-dependent predator–prey system with diffusion
Authors: Pang Peter Y. H. , Wang Mingxin
Published: July 2007

Ratio-dependent predator–prey models are favoured by many animal ecologists recently as they better describe predator–prey interactions where predation involves a searching process. When densities of prey and predator are spatially homogeneous, the so-called Michaelis–Menten ratio-dependent predator–prey system, which is an ordinary differential system, has been studied by many authors. The present paper deals with the case where densities of prey and predator are spatially inhomogeneous in a bounded domain subject to the homogeneous Neumann boundary condition. Its main purpose is to study qualitative properties of solutions to this reaction-diffusion (partial differential) system. In particular, we will show that even though the unique positive constant steady state is globally asymptotically stable for the ordinary-differential-equation dynamics, non-constant positive steady states exist for the partial-differential-equation model. This demonstrates that stationary patterns arise as a result of diffusion.
Conormal morphisms
Authors: Enochs Edgar , Rozas J. R. García , Oyonarte Luis , Jenda Overtoun M. G.
Published: July 2007

This article represents another step in our programme of obtaining a Galois theory and a coGalois theory when we have a category C and a given enveloping (for Galois) or covering (for coGalois) class. More precisely, in this paper, we study what should be understood by a conormal morphism between two objects of a given category and we characterize conormal morphisms between finite abelian groups when the covering class under consideration is that of torsion-free abelian groups.
Boundedness and asymptotic stability for delayed equations of logistic type
Authors: Faria Teresa , Liz Eduardo
Published: July 2007

For a scalar Lotka–Volterra-type delay equation ẋ(t) = b(t)x(t)[1 − L(xt)], where L: C([−r, 0];R) → R is a bounded linear operator and b a positive continuous function, sufficient conditions are established for the boundedness of positive solutions and for the global stability of the positive equilibrium, when it exists. Special attention is given to the global behaviour of solutions for the case of L a positive linear operator. The approach used for this situation is applied to address the global asymptotic stability of delayed logistic models in the more general form ẋ(t) = b(t)x(t)[a(t) − L(t, xt)], with L(t, ·) being linear and positive.
Saint-Venant's principle in blow-up for higher-order quasilinear parabolic equations
Authors: Galaktionov V. A. , Shishkov A. E.
Published: July 2007

We prove localization estimates for general 2mth-order quasilinear parabolic equations with boundary data blowing up in finite time, as t → T−. The analysis is based on energy estimates obtained from a system of functional inequalities expressing a version of Saint-Venant's principle from the theory of elasticity. We consider a special class of parabolic operators including those having fixed orders of algebraic homogenuity p > 0. This class includes the second-order heat equation and linear 2mth-order parabolic equations (p = 1), as well as many other higher-order quasilinear ones with p ≠ 1. Such homogeneous equations can be invariant under a group of scaling transformations, but the corresponding least-localized regional blow-up regimes are not group invariant and exhibit typical exponential singularities ~ e(T−t)−γ → ∞ as t → T−, with the optimal constant γ = 1/[m(p + 1) − 1] > 0. For some particular equations, we study the asymptotic blow-up behaviour described by perturbed first-order Hamilton–Jacobi equations, which shows that general estimates of exponential type are sharp.
Set products in transformation semigroups
Authors: Higgins Peter M. , Howie John M. , Ruškuc Nik
Published: July 2007

We describe products of arbitrary L-, R- and H-classes with the set of idempotents of full transformation semigroups.
Geodesics on the unit tangent bundle
Authors: Berndt J. , Boeckx E. , Nagy P. T. , Vanhecke L.
Published: July 2007

A geodesic γ on the unit tangent sphere bundle T1M of a Riemannian manifold (M, g), equipped with the Sasaki metric gS, can be considered as a curve x on M together with a unit vector field V along it. We study the curves x. In particular, we investigate for which manifolds (M, g) all these curves have constant first curvature κ1 or have vanishing curvature κi for some i = 1, 2 or 3.
Existence of a positive solution of an elliptic equation on RN
Authors: Liu Zhaoli , Wang Zhi-Qiang
Published: July 2007

We prove the existence of a positive solution for the Schrödinger-type equation on RN,−Δu + V(x)u = f(u) for u ∈ H1(RN), provided that

The result is obtained in two cases. (a) lim|x|→ ∞V(x) = V (∞) ∈ (0,∞), f is subcritical and supt>0 2F(t)t−2 < V (∞). (b) There exist V > 0 and R* > 0 such that f(t)t−1 < V ∞ ≤ V (x) for all t > 0 and |x| ≥ R*.
Some remarks on thin operators
Authors: Flores Julio
Published: July 2007

We show that if (Ω, Σ, μ) and (Ω′, Σ′, μ′) are probability spaces, then every regular operator T : Lp(μ) → Lq(μ′), 1 < p < ∞, 1 ≤ q < ∞, is thin if and only if it is strictly singular. We also show that if 0 ≤ S ≤ T : Lp(μ) → Lq(μ′), then T thin implies S is thin. We extend these results to some Köthe function spaces.
Approximation of the DNLS equation by the cubic nonlinear Schrödinger equation
Authors: Oliveira Filipe
Published: July 2007

We rigorously approach the Schrödinger equation of derivative type qt + iqxx + λ |q|2qx + μq2q̄x = 0, λ ∈ R, μ ∈ C, by the cubic nonlinear Schrödinger equation AT + i AXX + i k0 (λ − μ) |A|2A = 0. We also study the case of the KdV-like equation qt + i qxx + aqxxx + i |q|2q + λ̃ (|q|2q)x + μ̃ |q|2qx = 0, λ̃ μ̃ ∈ R, arising in optical physics.
On the transverse linear instability of solitary water waves with large surface tension
Authors: Pego Robert L. , Sun S. M.
Published: July 2007

The paper considers an incompressible and irrotational flow of a fluid with constant density bounded below by a rigid horizontal bottom and above by a free surface under the influence of gravity and surface tension. It is known that the full Euler equations have travelling two-dimensional solitary-wave solutions of small amplitude for large surface tension (Bond number greater than ⅓). This paper shows that these waves are linearly unstable to three-dimensional perturbations which oscillate along the wave crest with wavenumber in a finite band. The growth rates of these unstable modes are well approximated using the linearized Kadomtsev–Petviashvili equation with positive disper
Existence of solutions for some implicit partial differential equations and applications to variational integrals involving quasi-affine functions
Authors: Dacorogna Bernard , Ribeiro Ana Margarida
Published: July 2007

We discuss some existence theorems for partial differential inclusions, subject to Dirichlet boundary conditions, of the form

where Φ is a quasi-affine function and so, in particular, for Φ(Du) = det Du.

We then apply it to minimization problems of the form
Non-classical Riemann solvers with nucleation
Authors: LeFloch P. G. , Shearer M.
Published: July 2007

We introduce a new non-classical Riemann solver for scalar conservation laws with concave–convex flux-function. This solver is based on both a kinetic relation, which determines the propagation speed of (under-compressive) non-classical shock waves, and a nucleation criterion, which makes a choice between a classical Riemann solution and a non-classical one. We establish the existence of (non-classical entropy) solutions of the Cauchy problem and discuss several examples of wave interactions. We also show the existence of a class of solutions, called splitting–merging solutions, which are made of two large shocks and small bounded-variation perturbations. The nucleation solvers, as we call them, are applied to (and actually motivated by) the theory of thin-film flows; they help explain numerical results observed for such flows.
A link between the shape of the austenite–martensite interface and the behaviour of the surface energy
Authors: Elfanni A. , Fuchs M.
Published: July 2007

Let Ω ⊂ R2 denote a bounded Lipschitz domain and consider some portion Γ0 of ∂Ω representing the austenite–twinned-martensite interface which is not assumed to be a straight segment. We prove that

for an elastic energy density ϖ: R2 → [0 ∞) such that ϖ(0, ±1) = 0. Here, W(Ω) consists of all functions u from the Sobolev class W1, ∞(Ω) such that |uy| = 1 almost everywhere on Ω together with u = 0 on Γ0. We will first show that, for Γ0 having a vertical tangent, one cannot always expect a finite surface energy, i.e. in the above problem, the condition

in general cannot be included. This generalizes a result of [12] where Γ0is a vertical straight line. Property (*) is established by constructing some minimizing sequences vanishing on the whole boundary ∂Ω, that is, one can even take Γ0 = ∂Ω. We also show that the existence or non-existence of minimizers depends on the shape of the austenite–twinned-martensite interface Γ0.
Morse functions on Grassmann manifolds
Authors: Zhou Jianwei
Published: July 2007

In this paper we study the Morse functions on Grassmann manifolds. It is shown that many well-known calibrations can be used to construct degenerate Morse functions on Grassmann manifolds. In the study we use Clifford algebras and Lie groups.
Uniqueness for scalar conservation laws with discontinuous flux via adapted entropies
Authors: Audusse Emmanuel , Perthame Benoît
Published: July 2007

We prove uniqueness of solutions to scalar conservation laws with space discontinuous fluxes. To do so, we introduce a partial adaptation of Kružkov's entropies which naturally takes into account the space dependency of the flux. The advantage of this approach is that the proof turns out to be a simple variant of the original method of Kružkov. In particular, we do not need traces, interface conditions, bounded variation assumptions (neither on the solution nor on the flux), or convex fluxes. However, we use a special ‘local uniform invertibility’ structure of the flux, which applies to cases where different interface conditions are known to yield different solutions
Partial orders on linear transformation semigroups
Authors: Sullivan R. P.
Published: July 2007

Let V be any vector space and P(V) the set of all partial linear transformations defined on V, that is, all linear α: A → B, where A, B are subspaces of V. Then P(V) is a semigroup under composition, which is partially ordered by ⊆ (that is, α ⊆ β if and only if dom α ⊆ dom β and α = β | dom α). We compare this order with the so-called 'natural partial order' ≤ on P(V) and we determine their meet and join. We also describe all elements of P(V) that are minimal (or maximal) with respect to each of these four orders, and we characterize all elements that are 'compatible' with them. In addition, we answer similar questions for the semigroup T(V) consisting of all α ∈ P(V) whose domain equals V. Other orders have been defined by Petrich on any regular semigroup: three of them form a chain below ≤, and we show that two of these are equal on the semigroup P(V) and on the ring T(V). We also consider questions for these orders that are similar to those already mentioned
The existence of global attractors for a class of nonlinear dissipative evolution equations
Authors: Alarcon Eduardo Arbieto , Iorio Rafael José
Published: July 2007

In this work we consider the Cauchy problem associated with dissipative perturbations of infinite-dimensional Hamiltonian systems. we describe abstract conditions under which the problem is locally and globally well posed. Moreover, we establish the existence of global attractor. Finally, we present several applications of the theory.
Rikitake system: analytic and Darbouxian integrals
Authors: Valls Claudia
Published: July 2007

We give a complete characterization of the analytic and Darbouxian first integrals of the Rikitake system, which serves as a model for the reversal of polarity of the Earth's electromagnetic field. Our approach uses the Darboux theory of integrability.
Non-local homogenized limits for composite media with highly anisotropic periodic fibres
Authors: Cherednichenko K. D. , Smyshlyaev V. P. , Zhikov V. V.
Published: July 2007

We consider a homogenization problem for highly anisotropic conducting fibres embedded into an isotropic matrix. For a ‘double porosity’-type scaling in the expression of high contrast between the conductivity along the fibres and the conductivities in the transverse directions, we prove the homogenization theorem and derive two-scale homogenized equations using a version of the method of two-scale convergence, supplemented in the case when the spectral parameter λ = 0 by a newly derived variant of high-contrast Poincaré-type inequality. Further elimination of the 'rapid' component from the two-scale limit equations results in a non-local (convolution-type integro-differential) equation for the slowly varying part in the matrix, with the non-local kernel explicitly related to the Green function on the fibre. The regularity of the solution to the non-local homogenized equation is proved.
Unstable K1-group and homotopy type of certain gauge groups
Authors: Hamanaka Hiroaki , Kono Akira
Published: July 2007

We denote the group of homotopy set [X, U(n)] by the unstable K1-group of X. In this paper, using the unstable K1-group of the multi-suspended CP2, we give a necessary condition for two principal SU(n)-bundles over §4 to have the associated gauge group of the same homotopy type, which is an improvement of the result of Sutherland and, particularly, show the complete classification of homotopy types of SU(3)-gauge groups over S4.
Single-valued conjugates and holomorphic extendibility
Authors: Globevnik Josip
Published: July 2007

Let D be a bounded domain in the complex plane whose boundary consists of m ≥ 2 pairwise disjoint simple closed curves and let A(bD) be the algebra of all continuous functions on bD which extend holomorphically through D. We show that a continuous function Φ on bD belongs to A(bD) if for each g ∈ A (bD) the harmonic extension of Re(gΦ) to D has a single-valued conjugate.
Estimates for maximal singular integral operators in non-homogeneous spaces
Authors: Hu Guoen , Meng Yan , Yang Dachun
Published: July 2007

Under the assumption that the Radon measure μ on Rd satisfies only some growth condition, the authors prove that, for the maximal singular integral operator associated with a singular integral whose kernel only satisfies a standard size condition and the Hörmander condition, its boundedness in Lebesgue spaces Lp(μ) for any p ∈ (1, ∞) is equivalent to its boundedness from L1(μ) into weak L1(μ). As an application, the authors verify that if the truncated singular integral operators are bounded on L2(μ) uniformly, then the associated maximal singular integral operator is also bounded on Lp(μ) for any p ∈ (1, ∞).
Pairs of non-homogeneous linear differential polynomials
Authors: Langley J. K.
Published: July 2007

Let f be transcendental and meromorphic in the plane and let the non-homogeneous linear differential polynomials F and G be defined by

where k,n ∈ N and a, b and the aj, bj are rational functions. Under the assumption that F and G have few zeros, it is shown that either F and G reduce to homogeneous linear differential polynomials in f + c, where c is a rational function that may be computed explicitly, or f has a representation as a rational function in solutions of certain associated linear differential equations, which again may be determined explicitly from the aj, bj and a and b.
An ODE approach to the multiplicity of self-similar solutions for semi-linear heat equations
Authors: Naito Yūki
Published: July 2007

The Cauchy problem for semi-linear heat equations with singular initial data

is studied, where N > 2, p > (N + 2)/N, and l > 0 is a parameter. We establish the existence and multiplicity of positive self-similar solutions for the problem by applying the ordinary differential equation shooting method to the corresponding spatial profile problem.
The wavelet transform on spaces of type S
Authors: Pathak R. S. , Singh S. K.
Published: July 2007

The continuous wavelet transform is studied on certain Gel'fand–Shilov spaces of type S. It is shown that, for wavelets belonging to the one type of S-space defined on R, the wavelet transform is a continuous linear map of the other type of the S-space into a space of the same type (latter type) defined on R × R+. The wavelet transforms of certain ultradifferentiable functions are also investigated.
Radial solutions concentrating on spheres of nonlinear Schrödinger equations with vanishing potentials
Authors: Ambrosetti A. , Ruiz D.
Published: July 2007

We prove the existence of radial solutions of

concentrating on a sphere for potentials which might be zero and might decay to zero at infinity. The proofs use a perturbation technique in a variational setting, through a Lyapunov–Schmidt reduction.
Asymptotic stability for the Navier–Stokes equations in the marginal class
Authors: Zhou Yong
Published: July 2007

In this paper we consider the Navier–Stokes equations in Rn, n ≥ 3. We prove the asymptotic stability for weak solutions in the marginal class u ∈ L2(0, ∞; BMO), where ‘BMO’ denotes the bounded mean oscillation function, with arbitrary initial and external perturbations.
Homogenization of a class of quasilinear elliptic equations in high-contrast fissured media
Authors: Amaziane B. , Pankratov L. , Piatnitski A.
Published: July 2007

The aim of the paper is to study the asymptotic behaviour of the solution of a quasilinear elliptic equation of the form

with a high-contrast discontinuous coefficient aε(x), where ε is the parameter characterizing the scale of the microstucture. The coefficient aε(x) is assumed to degenerate everywhere in the domain Ω except in a thin connected microstructure of asymptotically small measure. It is shown that the asymptotical behaviour of the solution uε as ε → 0 is described by a homogenized quasilinear equation with the coefficients calculated by local energetic characteristics of the domain Ω.
COMIC ACTS OF (BE)LONGING: PERFORMING ENGLISHNESS INWONDERFUL ADVENTURES OF MRS. SEACOLE IN MANY LANDS
Authors: Poon Angelia
Published: July 2007

THE POWER THAT COMES FROMbeing English in the Victorian period is crucially dependent on a categorizing imperative that establishes and structures a series of distinctions such as those between citizen and foreigner, colonizer and colonized, and metropole and colony. These distinctions have epistemological borders that require policing, as do all cross-border interactions that threaten to muddy the imperial landscape with unsanctioned forms of knowledge and affiliation. It is against such a framework of constraints for understanding the regulation of Englishness that the story of the Jamaican-born Mary Seacole and her self-styled role as “Mother” Seacole to British soldiers during the Crimean War appears particularly pregnant with bothersome possibilities. Seeking self-consciously to identify herself with the “mother” country and the imperial metropole, she constantly tests the waters of reception by English society in the mid-nineteenth century. Seacole deploys the image of her racially different body in various noticeably frontier places, mainly Panama and the Crimea, to induce a recognition of herself, if not as English, then as at least functionally so. In so doing, she disrupts the claim to cultural or national identity that is frequently grounded in racial and geographical specificity. She puts strain on the idea of Englishness as foreclosed essence, demonstrating through performance and reiteration its irreduciblyperformativenature as discourse.
WILDE'S RENAISSANCE: POISON, PASSION, AND PERSONALITY
Authors: Ivory Yvonne
Published: July 2007

IN 1877,AS AN OXFORD UNDERGRADUATE, Oscar Wilde was invited to fill out two pages of a “Confession Album,” an informal survey of his likes, dislikes, ambitions, and fears. Wilde's answers testify to his deep appreciation for all things Greek: his favorite authors include Plato, Sappho, and Theocritus; he would hate to part with his Euripides; he admires Alexander the Great. But when faced with a question regarding the place he would most like to live, Wilde chooses not Athens or Argos but “Florence and Rome”; and when asked about the historical period in which he would most liked to have lived, Wilde opts for “the Italian Renaissance” (Holland 44–45). As there was no room on the form for Wilde to expand on this statement, we can only speculate as to why he saw Renaissance Italy as a time and a place in which he would have felt at home. But what the response tells us for certain is that while he was at Oxford, Wilde found the culture ofQuattro- andCinquecentoItaly particularly appealing, was comfortable imagining himself as part of that period, and was prepared to acknowledge his enthusiasm for the period to his friends. Moreover, it shows that while Wilde may have treasured the cultural artifacts of ancient Greece as a young man, he was more eager to experience the whole way of life captured in the idea of the Italian Renaissance.
Novel Tissue Engineered Tubular Heart Tissue forIn VitroPharmaceutical Toxicity Testing
Authors: Franchini Jessica L. , Propst John T. , Comer Gerald R. , Yost Michael J.
Published: July 2007

A growing problem in cardiac drug toxicity has been blamed on the lack of adequate testing prior to authorization for prescription use. This study offers an effective alternative to the current method ofin vivopharmaceutical testing, which is time and cost prohibitive. We have accomplished this by developing the novel three-dimensional heart tube model. At the “heart” of our model lies our patented collagen scaffold that enables the cardiac myocytes to display anin vivo–like architecture. The cardiac myocytes were cocultured with the collagen tube for a period of 5 weeks, resulting in the heart tubes. Our heart tubes were treated with specific drugs (nifedipine, isoproterenol, and lidocaine) at varying concentrations. The percent of apoptotic cells was calculated based on observing the number of cells that labeled positive for caspase-3 via confocal microscopy. All three drugs exhibited negative effects at high concentrations in that the number of living cells decreased. Lidocaine showed an increase in apoptosis at concentrations of 75 μM and above. This may indicate that certain drugs have a minimum concentration level that must be reached before the cells experience apoptosis from the toxic levels.
Characterization of human pre-elafin mutants: full antipeptidase activity is essential to preserve lung tissue integrity in experimental emphysema
Authors: Doucet Alain , Bouchard Dominique , Janelle Marie France , Bellemare Audrey , Gagné Stéphane , Tremblay Guy M. , Bourbonnais Yves
Published: July 2007

Pre-elafin is a tight-binding inhibitor of neutrophil elastase and myeloblastin; two enzymes thought to contribute to tissue damage in lung emphysema. Previous studies have established that pre-elafin is also an effective anti-inflammatory molecule. However, it is not clear whether both functions are linked to the antipeptidase activity of pre-elafin. As a first step toward elucidating the structure/function relationship of this protein, we describe here the construction and characterization of pre-elafin variants with attenuated antipeptidase potential. In these mutants, the P1′ methionine residue of the inhibitory loop is replaced by either a lysine (pre-elafinM25K) or a glycine (pre-elafinM25G) residue. Both mutated variants are stable and display biochemical properties undistinguishable from WT (wild-type) pre-elafin. However, compared with WT pre-elafin, their inhibitory constants are increased by one to four orders of magnitude toward neutrophil elastase, myeloblastin and pancreatic elastase, depending on the variants and enzymes tested. As suggested by molecular modelling, this attenuated inhibitory potential correlates with decreased van der Waals interactions between the variants and the enzymes S1′ subsite. In elastase-induced experimental emphysema in mice, only WT pre-elafin protected against tissue destruction, as assessed by the relative airspace enlargement measured using lung histopathological sections. Pre-elafin and both mutants prevented transient neutrophil alveolitis. However, even the modestly affected pre-elafinM25K mutant, as assayed in vitro with small synthetic substrates, was a poor inhibitor of the neutrophil elastase and myeloblastin elastolytic activity measured with insoluble elastin. We therefore conclude that full antipeptidase activity of pre-elafin is essential to protect against lung tissue lesions in this experimental model.
Quality and seasonal yields of promising forage species in the red soils region of southern China
Authors: Shilin Wen , Jones R. M. , Minggang Xu , Pingna Huang
Published: July 2007

Following increasing interest in the use of special purpose forages to provide quality feed for small holder beef farmers in the red soil region of inland southern China, 14 of the most promising accessions were evaluated over 2 years to measure their seasonal yield of leaf and stem. Seven grasses (six perennials and one annual) and two non-leguminous broadleaf herbs were fertilised with both 200 and 400 kg of nitrogen (N)/ha.year. Two herbs were fertilised with only 200 kg N/ha and three legumes were fertilised with 60 kg of N/ha. The accessions were evaluated under cutting, as cut-and-carry of improved forages is, and is likely to remain, more widely used than grazing in this region.
The highest yielding accessions were an elephant grass hybrid Guimu-1 [(Pennisetum purpureum × P. americanum) × P. purpureum cv. Mott] closely followed by elephant grass (P. purpureum) with total annual yields of 18–24 000 kg/ha in 2002, depending on accession and N rate, and 13–22 000 kg/ha in 2003. Their yields of leaf were 9–17 000 kg/ha in both years. Dwarf elephant grass cv. Mott gave similar yields of leaf but only half the yields of stem. Average leaf yields of the three elephant grass accessions were 24% higher at the higher rate of N in the first year and 40% higher in the second year.
With the exception of the herbs Cichorium intybus and Silphium perfoliatum, there was negligible growth in the cooler months (November–March) and the periods of peak growth were in July and August. C. intybus was the most promising of the legumes and herbs, but is damaged by waterlogging and disease.
Averaging over both years and all harvests, there was very little variation in the protein percentage of the different perennial grasses with levels of 12.4% at 200 kg N/ha and 13.7% at 400 kg N/ha. The corresponding protein percentage of the annual Mexican forage corn was higher (13.5 and 15.0%) but the legumes and herbs had a higher protein percentage (16–23%).
The most promising accession was dwarf elephant grass as it gives a high yield of leaf, but a relatively low percentage of stem. As such, it is well suited to a cut-and-carry system of feeding, especially as the time of cutting is less critical than with other forms of elephant grass, which can rapidly develop a high percentage of stem. However, given good management, higher yields of leaf can be obtained from the elephant grass hybrid.
Bax expression and apoptotic cell death in Fanconi anaemia peripheral blood lymphocytes
Authors: Baruque G. A. , Bitencourt M. A. , Pasquini R. , Castelo‐Branco M. T. L. , Llerena J. C. , Rumjanek V. M.
Published: July 2007

Abstract.  Objective: Deregulated apoptosis might be involved in some of the features of Fanconi anaemia (FA). The possibility that the pro‐apoptotic Bax protein could be involved in an increased susceptibility to apoptosis in FA patients was investigated. Materials and methods: Intracellular Bax expression, Bcl‐2 expression (an anti‐apoptotic protein) and cell death were analysed in 26 FA peripheral blood lymphocyte samples. Results: Most FA samples (69%) displayed increased levels of Bax and were more susceptible to both spontaneous apoptosis and mitogen activation‐induced cell death. Two subgroups were identified: one presented elevated levels of Bax (n = 18), whereas the other (n = 8), had Bax levels lower than controls. Two subgroups based on Bcl‐2 expression were also identified: one with normal and another with high Bcl‐2 expression. No inverse correlation was found between Bcl‐2 levels and Bax expression. A clear difference in susceptibility to induced cell death could be observed between control and FA samples. The best correlation was observed between high levels of Bax and mitogen‐induced apoptosis of cells; these displayed characteristics of necrosis secondary to apoptosis, suggesting that the intrinsic apoptotic pathway was being activated. Conclusion: Despite increased susceptibility to cell death induction, there was no correlation between Bax levels, chromosome breakage, haematological parameters or androgen therapy. The importance of apoptosis and Bax expression in the clinical development of FA awaits clarification.
Polo‐like kinase 1 regulates RhoA during cytokinesis exit in human cells
Authors: Dai B. N. , Yang Y. , Chau Z. , Jhanwar‐Uniyal M.
Published: July 2007

Abstract.  Objective: Both RhoA (Rho1) and polo‐like kinase 1 (Plk1) are implicated in the regulation of cytokinesis, a cellular process that marks the division of cytoplasm of a parent cell into daughter cells after nuclear division. Cytokinesis failure is often accompanied by the generation of cells with an unstable tetraploid content, which predisposes it to chromosomal instability and oncogenic transformation. Several studies using lower eukaryotic systems demonstrate that RhoA and Plk1 are essential for mitotic progression and cytokinesis. Materials and methods: Physical and functional interactions between RhoA and Plk‐1 were analyzed using subcellular localization of RhoA and Plk1 in HeLa cells by immunofluorescence and co‐precipitation techniques, followed by Western blotting in RhoA transfected cells. Results: Plk1 localizes to kinetochores as well as to spindle poles during prophase and metaphase; it translocates to the midbody during telophase. RhoA is also enriched at the midbody region during telophase and colocalizes with Plk1. Recombinant RhoA, expressed as a GFP fusion protein, is enriched in the nucleus of HeLa and U2OS cells. Ectopically expressed GFP‐RhoA does not cause significant cell death, although there exist a group of cells that appear to exhibit a delay in mitotic exit or in impaired cytokinesis. Conclusion: Co‐immunoprecipitation reveals that RhoA and Plk1 physically interact and that their interaction appears to be enhanced during mitosis. Given the role of RhoA and Plk1 in cytokinesis, our findings suggest that regulated activation of RhoA is important for cytokinesis and that Plk1 may alter activation of RhoA during mitotic cytokinesis.
Epithelial stem cells of the eye surface
Authors: Revoltella R. P. , Papini S. , Rosellini A. , Michelini M.
Published: July 2007

Abstract.  Objectives: Epithelial stem cells of the eye surface, of the cornea and of the conjunctiva, have the ability to give rise to self renewal and progeny production of differentiated cells with no apparent limit. The two epithelia are separated from each other by the transition zone of the limbus. The mechanisms adopted by stem cells of the two epithelia to accomplish their different characteristics, and how their survival, replacement and unequal division that generates differentiated progeny formation are controlled, are complex and still poorly understood. They can be learned only by understanding how stem cells/progenitors are regulated by their neighbouring cells, that may themselves be differently unspecialised, forming particular microenvironments, known as ‘niches’. Stem cells operate by signals and a variety of intercellular interactions and extracellular substrates with adjacent cells in the niche. Technical advances are now making it possible to identify zones in the corneal limbus and conjunctiva that can house stem cells, to isolate and expand them ex vivo and to control their behaviour creating optimal niche conditions. With improvements in biotechnology, regenerative cornea and conjunctiva transplantation using adult epithelial stem cells becomes now a reality. Results and Conclusions: Here we review our current understanding of stem cell niches and illustrate recent significant progress for identification and characterization of adult epithelial stem cells/progenitors at cellular, molecular and mechanistic levels, improvement in cell culture techniques for their selective expansion ex vivo and prospects for a variety of therapeutic applications.