bluuebunny/crossref_metadata_2025 huggingface dataset:
Periodic Solutions of Linear Integro‐Differential Equations
Authors: Burton T. A. , Eloe P. W. , Islam M. N.
Published: November 2010

Using a degree‐theoretic result of Granas, a homotopy is constructed enabling us to show that if there is an a priori bound on all possible T‐periodic solutions of a Volterra equation, then there is a T‐periodic solution. The a priori bound is established by means of a Liapunov functional. The latter result is unusual in that no bounds on the Liapunov functional are required. Thus, in addition to the periodic solution, the equation may have both bounded and unbounded Solutions.
Quadratic Control for Stochastic Systems Defined by Evolution Operators and Square Integrable Martingales
Authors: Tudor C.
Published: November 2010

The infinite dimensional version of the linear quadratic cost control problem is studied by Curtain and Pritchard [2], Gibson [5] by using Riccati integral equations, instead of differential equations. In the present paper the corresponding stochastic case over a finite horizon is considered. The stochastic perturbations are given by Hilbert valued square integrable martingales and it is shown that the deterministic optimal feedback control is also optimal in the stochastic case. Sufficient conditions are given for the convergence of approximate solutions of optimal control problems.
Generalized Cauchy Spaces
Authors: Eklund Patrik , Gähler Werner
Published: November 2010

In this paper a unified theory of Cauchy spaces is presented including the classical cases of filter and sequence Cauchy spaces. To by‐pass a lattice‐theoretical barrier the notion of Urysohn modification of a functor is introduced. Employing this notion for many types of generalized Cauchy spaces a completion method is given.
Decompositions in Edge and Corner Singularities for the Solution of the Dirichlet Problem of the Laplacian in a Polyhedron
Authors: Petersdorff T. V. , Stephan E. P.
Published: November 2010

The solution of the three‐dimensional Dirichlet problem for the Laplacian in a polyhedral domain has Special singular forms at corners and edges. The main result of this paper is a “tensor‐product” decomposition of those singular forms along the edges. Such a decomposition with both edge singularities, additional corner singularities and a smoother remainder refines known regularity results for the solution where either the edge singularities are of non‐tensor product form or the remainder term belongs to an anisotropic Sobolev space for data given in an isotropic Sobolev space.
A Classification of Non‐Degenerated Binary Forms
Authors: Martin Bernd
Published: November 2010

There is given a representation of the equivalence classes of non‐degenerated binary forms of degree d as quotient of an affine open subset of (d – 3)‐dimensional affine space by the d‐th symmetric group.
Extensions of Positive Definite Fredholm Operators with Partially Zero Inverse
Authors: Bakonyi Mihaly , Woerdeman Hugo J.
Published: November 2010

Considered is the problem of adjusting a positive definite operator in order to obtain a partially zero inverse. Using generalized determinants the problem is settled for operator matrices with Hilbert Schmidt off diagonal entries. For Fredholm integral operators an approximation result is obtained.
On the Poles of the Local Resolvent
Authors: Bermúdez Teresa , González Manuel , Martinón Antonio
Published: November 2010

We give two characterizations of the isolated singularities of the local resolvent function of an operator T ε L(X) at a point ε of a complex Banach space X: in terms of a suitable decomposition of ε, and in terms of the existence of a sequence in X related with the Laurent series of the local resolvent function. Moreover, we introduce the locally chain‐finite operators at a point ε and show that T is chain‐finite if and only if T is locally chain‐finite at every χ ε X.
Starshapedness of Level Sets for Solutions of Nonlinear Elliptic Equations
Authors: Francini Elisa
Published: November 2010

We introduce a measure for the starshapedness of the level sets of solutions of certain nonlinear elliptic equations in a starshaped ring Ω of IRn. We prove that a function which characterizes the starshapedness does not attain its minimum in Ω.
Integrability Properties of the Maximal Operator on Partial Sums of Fourier Series in Orlicz Spaces
Authors: Kitax Hiro‐O
Published: November 2010

Let S* (f be the majorant function of the partial sums of the trigonometric Fourier series of f. In this paper we consider the Orlicz space Lπ and give a generalization of Soria's result [S1]. Let π (t) be a concave function with some nice properties and

. If there exists a positive constant a0 < 1 such that

then we have

.
Bounded and Almost Periodic Solutions of Linear High‐Order Hyperbolic Equations
Authors: Shirikyan Armen , Volevich Leonid
Published: November 2010

The present paper is devoted to investigating high‐order strictly hyperbolic operators with nearly constant coefficients. The invertibility of these operators in spaces of functions uniformly bounded or almost periodic in time is established, provided the symbol of the operator in question has no roots in an open strip containing the real line. Under the additional condition that the strip coincides with a half‐plane, exponentially decaying solutions of the nonhomogeneous equation with right‐hand side of exponential decay are constructed. In the case of equations with constant coefficients the necessity of the derived conditions is proved. The results of this paper were announced without proofs in [SV].
On Conformal Structure in Space‐Time and Nets of Local Algebras of Observables
Authors: Wollenberg Manfred
Published: November 2010

In this paper we continue the study of the question of how to reconstruct the conformal structure (causality relation) of a space‐time from a net of local algebras of observables on the underlying manifold.
Zur Klassifikation Vierdimensionaler Reeller Divisionsalgebren
Authors: Dieterich Ernst
Published: November 2010

Zu jeder Konfiguration des IR3, welche aus einem Ellipsoid in Hauptachsenform und einem Punktepaar besteht, wird eine vierdimensionale reelle Divisionsalgebra konstruiert. Diese Konstruktion induziert eine Bijektion zwischen den Äquivalenzklassen von Konfigurationen und den Isomorphieklassen vierdimensionaler potenzassoziativer reeller Divisionsalgebren. Hierbei sind zwei Konfigurationen genau dann äquivalent, wenn ihre Ellipsoide übereinstimmen und ihre Punktepaare in derselben Bahn unter der Operation der eigentlichen Symmetriegruppe des Ellipsoids liegen. Ein Querschnitt für die Äquivalenzklassen von Konfigurationen wird angegeben.
Nonexistence of Solutions and an Anti‐Maximum Principle for Cooperative Systems with the p‐Laplacian
Authors: Fleckinger‐Pelle Jacqueline , Gossez Jean‐Pierre , Takáĉ Peter , de Thélin François
Published: November 2010

We obtain a nonexistence result and an anti‐maximum principle for weak solutions u = (u1,…, un) to the following strictly cooperative elliptic system,

equation image

Here, Ω C IRN is a bounded domain with a C2,α ‐ boundary δΩ, for some α ∈ (0,1), Δp denotes the p‐Laplacian defined by Δpu = div (|∇u|p‐2∇u) for p 6 (1,∞), and the coefficients aij (1 ≤ i,j ≤ n) are assumed to be constants satisfying aij > 0 for i ≠ j (a strictly cooperative system). We assume 0 ≤ fi, ∈ L∞(Ω) (1 ≤ i ≤ n). For ∇+ = ∇‐ ∇‐ = ∈ IR and f = (f1,…,fn) 0 in Ω, let μ1 denote the first eigenvalue of the (p ‐ 1)‐homogeneous system (S). Assuming f ≠ 0 in Ω, we show: (i) if ∧+ = ∧‐ = μ1, then (S) has no solution; and (ii) if ∧+, ∧‐ ∧ (μ1,μ1 + δ), for some δ > 0 small enough, then ui < 0 in Ω and δui/δv > 0 on δΩ (1 ≤ i ≤ n). Our methods for the system (S) are completely different from the case n = 1 (a single equation). For n ≥ 2 and p ≥ 2, mild additional hypotheses are imposed on the domain Ω and the matrix

equation image
.
Canonical Systems with Rational Spectral Densities: Explicit Formulas and Applications
Authors: Gohberg I. , Kaashoek M. A. , Sakhnovich A. L.
Published: November 2010

This paper solves explicitly the direct spectral problem of canonical differential systems for a special class of potentials. For a potential from this class the corresponding spectral function may have jumps and its absolutely continuous part has a rational derivative possibly with zeros on the real line. A direct and self‐contained proof of the diagonalization of the associated differential operator is given, including explicit formulas for the diagonalizing operator and the spectral function. This proof also yields an explicit formula for the solution of the inverse problem. As an application new representations are derived for a large class of solutions of nonlinear integrable partial differential equations. The method employed is based on state space techniques and uses the idea of realization from mathematical system theory.
Determinants of Regular Singular Sturm ‐ Liouville Operators
Authors: Lesch Matthias
Published: November 2010

We consider a regular singular Sturm‐Liouville operator

equation image

on the line segment (0,1]. We impose certain boundary conditions such that we obtain a semi‐bounded self‐adjoint operator. It is known (cf. Theorem 1.1 below) that the ζ‐function of this operator

equation image

has a meromorphic continuation to the whole complex plane with 0 being a regular point. Then, according to [RS] the ζ ‐ regularized determinant of L is defined by

equation image

In this paper we are going to express this determinant in terms of the solutions of the homogeneous differential equation Ly = 0 generalizing earlier work of S. Levit and U. Smilansky [LS], T. Dreyfus and H. Dym [DD], and D. Burghelea, L. Friedlander and T. Kappeler [BFK1, BFK2). More precisely we prove the formula

equation image

Here ϕ ψ is a certain fundamental system of solutions for the homogeneous equation Ly = 0, W(ϕ ψ), denotes their Wronski determinant, and v0, v1 are numbers related to the characteristic roots of the regular singular points 0, 1.
Oscillation and Nonoscillation Criteria for Second Order Linear Differential Equations
Authors: Li Horng‐Jaan , Yeh Cheh‐Chih
Published: November 2010

Oscillation and nonoscillation criteria are established for the second order linear differential equation

equation image

under the hypothesis that p(t) > 0 and

equation image

where a(t) ∈ C2([t0,∞);(0,∞)) is a given function. These results improve some well‐known oscillation and nonoscillation criteria.
The Point Spectrum of Unitary Dilations in Kreĭ Spaces
Authors: Temme Dirk
Published: November 2010

For a bicontractive operator T on a Kreĭ space the connections between its eigenvalues and eigenstructure and the eigenvalues and eigenstructure of its minimal unitary dilation U are studied. For eigenvalues on the unit circle of T in general only part of the eigenspace of T will return its an eigenspace of U and the corresponding eigenvalue will be a singular critical point of U.
Limit Theorems for Logarithmic Averages of Random Vectors
Authors: Berkes István , Horváth Lajos
Published: November 2010

We prove the strong law of large numbers for logarithmic averages of random vectors. We also obtain a strong approximation for logarithmic averages.
Invariant Operators and the Berezin Transform on Cartan Domains
Authors: Engliš Miroslav
Published: November 2010

Let Ω be an irreducible Cartan domain of rank r and genus p and Bv (c > p ‐ 1) be the Berezin transform on Ω. It is known that as v tends to infinity, the Berezin transform admits the asymptotic expansion Bν∼∑k=0∞ Qkν−k where the Qk's are certain invariant differential operators — for instance, Q0 is the identity and Q1 is the Laplace ‐ Beltrami operator. [See A. Unterberger and H. Upmeier, Comm. Math. Phys. 164 (1994), 563–598.] In the present paper we show that the operators Qk generate the whole ring of invariant differential operators on Ω; in fact, Q1, Q3,…, Q2r‐1 and Q0 form a set of free generators. A bounded version of this result is also given: for any v > p ‐ 1, the r+1 operators Bv, Bv+1,…, Bv+r are a set of generators for the von Neumann algebra 3 of all G ‐ invariant bounded linear operators on L2(Ω); this algebra can be identified with the algebra of all L2 ‐ bounded Fourier multipliers, or of all bounded operators which are functions, in the L2 ‐ spectral‐theoretic sense, of certain normal extensions of the invariant differential operators.
Analytic Extension of Non Quasi ‐ Analytic Whitney Jets of Beurling Type
Authors: Schmets Jean , Valdivia Manuel
Published: November 2010

Let (Mr)r∈ℕ0 be a logarithmically convex sequence of positive numbers which verifies M0 = 1 as well as Mr ≥ 1 for every r ∈ ℕ and defines a non quasi ‐ analytic class. Let moreover F be a closed proper subset of ℝn. Then for every function f on ℝn belonging to the non quasi ‐ analytic (Mr)‐class of Beurling type, there is an element g of the same class which is analytic on ℝ,n F and such that Dαf(x) = Dαg(x) for every α ∈ ℕn0 and x ∈ F.
The k ‐ Very Ampleness and k ‐ Spannedness on Polarized Abelian Surfaces
Authors: Terakawa Hiroyuki
Published: November 2010

We give a numerical criterion for an ample line bundle on an abelian surface to be it‐very ample for a nonnegative integer k. This result implies the equivalence of k‐very ampleness and k‐spannedness. We also give a complete classification of polarized abelian surfaces with k ‐ very ample polarizations. Our results extend those of Bauer and Szemberg [BaSzl] and Ramanan [Ra].
Picard Operators
Authors: Weikard Rudi
Published: November 2010

A linear differential expression Ly = y(n) + qn‐2yn‐2 +…+ q0y is called a Picard expression if its coefficients are elliptic functions (with common fundamental periods) and if the general solution of Ly = Ey is an everywhere meromorphic function (with respect to the independent variable) for all E ∈ ℂ.

If L is a Picard expression we show that the differential equation Ly = Ey has n linearly independent Floquet solutions except when E is any of a finite number of exceptional values. Also the conditional stability set of a Picard expression (and hence the spectrum of the associated operator in L2(ℝ)) consists of finitely many regular analytic arcs.
Reconstruction from Line Integrals in Spaces of Constant Curvature
Authors: Palamodov Victor P.
Published: November 2010

New reconstruction formula for the line integral transformation in Euclidean spaces is found. The general k‐plane integral transform in Euclidean space is related to a totally geodesic integral transform for an arbitrary Riemannian space of constant curvature by means of a factorization property. Duality theorems for the totally geodesic transforms are stated.
On Subspaces of the Spaces L and of Their Strong Duals
Authors: Albanese Angela A.
Published: November 2010

For Ω an open subset of IRN and 1 < p < ∞, we prove that any complemented subspace E of Lploc (Ω) contains either a complemented copy of (l2)IN or a complemented copy of (lp)IN, provided ≈︁ F ≈︁ and ω and ≈︁ ω⊕ F with F Banach space. We also prove that any complemented subspace E of (Lploc(Ω))1β contains either a complemented copy of (l2)(IN) or a complemented copy of (lp)(IN), provided E ≈︁ F, ≈︁ π and ≈︁ π ⊕ F with F Banach space.
Operator Ideals, Orthonormal Systems and Lacunary Sets
Authors: Baur Franziska
Published: November 2010

Given an orthonormal system B in some L2(u) we consider the operator ideals IIB and TB of B‐summing and B‐type operators and some related ideals. We characterize by certain weak compactness properties when IIB is equal to the operator ideal II2 of 2‐summing operators. In lose that B consists of characters of a compact abelian group we characterize when IIB coincides with the operator ideal IIγ of Gauss‐summing operators and when TB coincides with the operator ideal IIp of type‐2 operators. Moreover, we give a necessary and sufficient condition for Fig to contain the operator ideal IIp of p‐summing operators (2 < p < ∞) and for TB to contain the operator ideal Γp of p ‐ factorable operators.
Stability of Bifurcating Periodic Solutions of Differential Inequalities in IR3
Authors: Kučera Milan
Published: November 2010

A bifurcation problem for the inequality

, is considered, where K is a closed convex cone in IR3, Aλ a real 3×3 matrix depending continuously on a real parameter λ, G a small perturbation. Small periodic solutions bifurcating at λ0 from the branch of trivial solutions are studied. It is proved that these solutions are stable or they are contained in a certain attracting set Aλ if they correspond to parameters λ for which the trivial solution is unstable. Further, unstable solutions exist among them if they correspond to parameters for which the trivial solution is stable.
Entropy, Approximation Quantities and the Asymptotics of the Modulus of Continuity
Authors: Richter Christian
Published: November 2010

The paper deals with the approximation of bounded real functions f on a compact metric space (X, d) by so‐called controllable step functions in continuation of [Ri/Ste]. These step functions are connected with controllable coverings, that are finite coverings of compact metric spaces by subsets whose sizes fulfil a uniformity condition depending on the entropy numbers εn(X) of the space X. We show that a strong form of local finiteness holds for these coverings on compact metric subspaces of IRm and Sm. This leads to a Bernstein type theorem if the space is of finite convex information. In this case the corresponding approximation numbers εn(f) have the same asymptotics its ω(f, εn(X)) for f ε C(X). Finally, the results concerning functions f ε M(X) and f ε C(X) are transferred to operators with values in M(X) and C(X), respectively.
On Possible Singular Solutions to the Navier — Stokes Equations
Authors: Málek Josef , Nečas Jindřich , Pokorný Milan , Schonbek Maria E.
Published: November 2010

In this paper, we exclude the possibility of existence of a singular solution of the selfsimilar type proposed by Jean Leray More precisely, using a slightly stronger hypothesis we give a simpler proof to the analogous result established by J. Nečas, M. Rúžička and V. Šverák. We also discuss the possible existence of a singular solution of pseudo‐selfsimilar type.
Local Solutions of Weakly Parabolic Semilinear Differential Equations
Authors: Dreher Michael , Pluschke Volker
Published: November 2010

Semilinear parabolic boundary value problems with degenerated elliptic part where the right‐hand side depends on the solution are studied. We approximate the parabolic semilinear problem by a system of linear degenerate elliptic problems by the aid of semidiscretization in time. Using weighted Sobolev spaces one derives a‐priori‐estimates for the approximate solutions. These approximate solutions converge to a uniquely determined weak solution, if the time interval is sufficiently small. We point out that the nonlinear right‐hand side is defined only in a neighbourhood of the initial data, therefore one has to prove L∞‐estimates for the solutions of the approximate problems.
Integral Operators in Sobolev Spaces on Domains with Boundary
Authors: Witte Jörg
Published: November 2010

Properties of integral operators with weak singularities arc investigated. It is assumed that G ⊂ ℝn is a bounded domain. The boundary δG should be smooth concerning the Sobolev trace theorem. It will be proved that the integral operators \documentclass{article}\pagestyle{empty}\begin{document}$\int {_G \frac{{f\left(\Theta \right)}}{{x - y|^{n - 1} }}u\left(\nu \right)d\partial G_\nu }$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ \int {_{\partial G} \frac{{f\left(\Theta \right)}}{{|x - y|^{n - 1} }}u\left(y \right)d\partial G_y }$\end{document} maps Wpk(G) into Wpk+1(G) and Wpk−1(G) into Wpk/p(G), respectively, and are bounded. Here θ ∈ S ⊂ ℝn, where S is the unit sphere. Furthermore, f possesses bounded first order derivatives and is bounded on S. Then applications to first order systems are discussed.
On Contact Submanifolds in Complex Projective Spaces
Authors: Djorić Mirjana , Okumura Masafumi
Published: November 2010

We treat n‐dimensional real submanifolds of complex projective spaces in the case when the maximal holomorphic tangent subspace is (n ‐ 1)‐dimensional. In particular, we study the case when the induced almost contact structure on a submanifold is contact, we establish a few characteristics of the shape operator with respect to the distinguished vector field and we give one characterization of a contact submanifold in this case
On Auslander‐Reiten Quivers of Enveloping Algebras of Restricted Lie Algebras
Authors: Farnsteiner Rolf
Published: November 2010

Let (L, [p]) be a finite dimensional restricted Lie algebra over an algebraically closed field F of characteristic p ≥ 3, X ∈ L* a linear form. In this article we study the Auslander‐Reiten quivers of certain blocks of the reduced enveloping algebra u(L,x). In particular, it is shown that the enveloping algebras of supersolvable Lie algebras do not possess AR‐components of Euclidean type.
On the Generalized Ray‐Singer Conjecture for Covering Spaces
Authors: Gong Donggeng
Published: November 2010

We find a relation between L2 ‐combinatorial torsion and analytic torsion associated with a small spectrum of the Witten‐type Laplacian on a covering space. The result is used as one crucial step in a proof of the generalized Ray‐Singer conjecture for covering spaces.
Algebraic Independence of Sums of Reciprocals of the Fibonacci Numbers
Authors: Nishioka Kumlko , Tanaka Taka‐Aki , Toshimitsu Takeshi
Published: November 2010

Algebraic independence of the numbers
equation image
where {Rn}n≥0 is a sequence of integers satisfying a binary linear recurrence relation and {bh}h≥0 is a periodic sequence of algebraic numbers not identically zero, are studied.
A New Class of Soliton Solutions for the (Modified) Kadomtsev‐Petviashvili Equation
Authors: Renger Walter
Published: November 2010

We construct solutions of the Kadomtsev‐Petviashvili equation and its counterpart, the modified Kadomtsev‐Petviashvili equation, with an infinite number of solitons by a careful examination of the limits of N‐ soliton solutions as N → ∞. We give sufficient conditions to ensure that these limits exist and satisfy the (modified) Kadomtsev‐Petviashvili equation.
Non Integral Regularizing Operators on Lp‐ Spaces
Authors: Voigt Jürgen
Published: November 2010

We present bounded positivity preserving operators from Lp(ℝ) to Lq (ℝ), for 1 < p < ∞, 1/p‐1/q < 1/2, which are not integral operators.
Screen Problem for Vector Helmholtz Equation
Authors: Sigua L.
Published: November 2010

The paper deals with the screen boundary value problem for vector Helmholtz equation in the three‐dimensional space. Using the method of boundary integral equations and the theory of elliptic pseudodifferential operators on manifolds with boundary we prove uniqueness and existence theorems in Bessel‐potential and Besov spaces and establish Cα‐smoothness (with α < 1/2) of solutions up to the boundary.
Cartilage ultrastructure in proteoglycan‐deficient zebrafish mutants brings to light new candidate genes for human skeletal disorders
Authors: Wiweger Malgorzata I , Avramut Cristina M , de Andrea Carlos E , Prins Frans A , Koster Abraham J , Ravelli Raimond BG , Hogendoorn Pancras CW
Published: November 2010

Proteoglycans are molecules consisting of protein cores onto which sugar chains, i.e., glycosaminoglycans (GAGs) such as heparan or chondroitin sulphates, are attached. Proteoglycans are produced by nearly all cells, and once secreted they become a major component of the extracellular matrix. Cartilage is particularly rich in proteoglycans, and changes in the structure and composition of GAGs have been found in osteochondromas and osteoarthritis. The zebrafish (Danio rerio) exhibits fast development, a growth plate‐like organization of its craniofacial skeleton and an availability of various mutants, making it a powerful model for the study of human skeletal disorders with unknown aetiology. We analysed skeletons from five zebrafish lines with known mutations in genes involved in proteoglycan synthesis: dackel (dak/ext2), lacking heparan sulphate; hi307 (β3gat3), deficient for most GAGs; pinscher (pic/slc35b2), presenting defective sulphation of GAGs and other molecules; hi954 (uxs1), lacking Notch and most GAGs due to impaired protein xylosylation; and knypek (kny/gpc4), missing the protein core of the Glypican‐4 proteoglycan. Here we show that each mutant displays different phenotypes related to: (a) cartilage morphology; (b) composition of the extracellular matrix; (c) ultrastructure of the extracellular matrix; and (d) the intracellular ultrastructure of chondrocytes, proving that sulphated GAGs orchestrate the cartilage intra‐ and extracellular ultrastructures. The mild phenotype of the hi307 mutant suggests that proteoglycans consisting of a protein core and a short sugar linker might suffice for proper chondrocyte stacking. Finally, knypek supports the involvement of Glypican‐4 in the craniofacial phenotype of Simpson–Golabi–Behmel syndrome and suggests GPC4 as a modulator of the overgrowth phenotype that is associated with this syndrome and is primarily caused by a mutation in GPC3. Moreover, we speculate on the potential involvement of SLC35B2, β3GAT3 and UXS1 in skeletal dysplasias. This work promotes the use of zebrafish as a model of human skeletal development and associated pathologies. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Performance comparison of AlGaAs, GaAs and InGaP tunnel junctions for concentrated multijunction solar cells
Authors: Wheeldon Jeffrey F. , Valdivia Christopher E. , Walker Alexandre W. , Kolhatkar Gitanjali , Jaouad Abdelatif , Turala Artur , Riel Bruno , Masson Denis , Puetz Norbert , Fafard Simon , Arès Richard , Aimez Vincent , Hall Trevor J. , Hinzer Karin
Published: November 2010

Four tunnel junction (TJ) designs for multijunction (MJ) solar cells under high concentration are studied to determine the peak tunnelling current and resistance change as a function of the doping concentration. These four TJ designs are: AlGaAs/AlGaAs, GaAs/GaAs, AlGaAs/InGaP and AlGaAs/GaAs. Time‐dependent and time‐average methods are used to experimentally characterize the entire current–voltage profile of TJ mesa structures. Experimentally calibrated numerical models are used to determine the minimum doping concentration required for each TJ design to operate within a MJ solar cell up to 2000‐suns concentration. The AlGaAs/GaAs TJ design is found to require the least doping concentration to reach a resistance of <10−4 Ω cm2 followed by the GaAs/GaAs TJ and finally the AlGaAs/AlGaAs TJ. The AlGaAs/InGaP TJ is only able to obtain resistances of ≥5 × 10−4 Ω cm2 within the range of doping concentrations studied. Copyright © 2010 John Wiley & Sons, Ltd.
Building interacting partner predictors using co‐varying residue pairs between histidine kinase and response regulator pairs of 48 bacterial two‐component systems
Authors: Choi Kwangmin , Kim Sun
Published: November 2010

The two‐component system (TCS) is a signal transduction system that involves a histidine kinase (HK) and a response regulator (RR). Although up to hundreds of TCSs may operate in parallel in a bacterial cell, the high‐fidelity of a TCS signaling is well maintained, minimizing irrelevant crosstalk between TCSs. When a HK gene and a RR gene in a given TCS system exist in neighboring positions, it is almost certain that their protein products (i.e., HK and RR) are interacting partners. However, large bacterial genomes often have multiple HK genes and/or cognate RR genes that are not neighboring positions. In many partially assembled genomes, some HK genes and RR genes belong to different contigs. In these cases, it is not clear which HK(s) and RR(s) interact. By combining information‐theoretic and graph‐theoretic approaches, we developed a computational method identifying co‐evolving residue pairs between HKs and cognate RRs and predicting the interacting HK:RR pairs for each TCS. In addition, we built a TCSppWWW webserver (http://compath.org/platcom/tcs) that takes query sequences of pairing candidates and predicts their HK:RR pairing using precomputed models. The current release of TCSppWWW provides predictors for 48 TCSs using over 20,000 protein sequences from about 900 bacterial genomes. Three different types of predictors using Random Forest, RBF Network, and Naïve Bayes are provided. Once a set of HK and RR candidate sequences are submitted, TCSppWWW aligns query sequences to the precomputed multiple sequence alignment of HK:RR pairs, extracts co‐evolving column positions, then returns prediction results with prediction margin and additional information. Proteins 2011. © 2010 Wiley‐Liss, Inc.
Optical property and thermal stability of Mo/Mo–SiO2/SiO2 solar‐selective coating prepared by magnetron sputtering
Authors: Wang Jian , Wei Baocheng , Wei Qirui , Li Dejie
Published: November 2010

Mo/Mo–SiO2/SiO2 solar‐selective coating for high‐temperature solar thermal application is prepared on quartz glass by direct‐current (DC) and radio‐frequency (RF) co‐sputtering. The normal solar absorptance αn = 0.95 and thermal emittance εn = 0.097 (353 K) are obtained through process optimization. The normal reflectance Rn(λ) before and after 1073 K vacuum annealing, are measured by ultraviolet–visible–infrared (UV–VIS–IR) and Fourier transform infrared (FT‐IR) spectroscopy. There is only a slight increase in Rn(λ) in IR region after annealing, which results in a lower εn = 0.075 (353 K). The crystallized grain of Mo in the coating, obtained from XRD pattern, increased from 23 to 60 nm after vacuum annealing. These phenomena are mainly caused by the change of crystal state and reflectance of Mo IR layer according to the comparison of Rn(λ) and XRD patterns of Mo/SiO2 and Mo–SiO2/SiO2 tandem films.

magnified image

The near‐normal reflectance of Mo/Mo–SiO2/SiO2 solar‐selective coating before and after 1073 K vacuum annealing.
Annealing effect on local nucleation fields in bistable microwires
Authors: Ipatov M. , Zhukova V. , Gonzalez J. , Zhukov A.
Published: November 2010

We have investigated the influence of annealing on the local nucleation fields distribution in amorphous magnetically bistable microwires. The measurements have quite surprisingly shown a considerable increase of the local nucleation fields after annealing of the wire, although it is generally expected that thermal annealing without a magnetic field relieves the internal stresses, which results in a reduction of the nucleation fields. The increase of the local nucleation fields is explained by the disappearance of local inhomogeneities after annealing.
A mechanism for moistening the lower stratosphere involving the Asian summer monsoon
Authors: Dethof A. , O'Neill A. , Slingo J. M. , Smit H. G. J.
Published: November 2010

This study employs European Centre for Medium‐Range Weather Forecasts (ECMWF) re‐analysis data and the contour advection technique to investigate the water vapour distribution in the upper troposphere and lower stratosphere. Water vapour is the primary greenhouse gas and understanding the processes which determine its distribution and transport is crucial. Of special interest is the exchange of water vapour across the tropopause. This study considers how the Asian summer monsoon affects the moisture budget of the upper troposphere and lower stratosphere. The region of the Asian summer monsoon is identified as a significant moisture source for the upper troposphere outside the deep tropics. Monsoon convection moistens the region of the upper‐level monsoon anticyclone which is located close to the dynamical tropopause, where isentropes cross from the troposphere into the stratosphere. An isentropic analysis reveals that transport from the troposphere into the stratosphere in this region is normally prevented by the strong potential‐vorticity gradients around the tropopause. However, midlatitude synoptic disturbances occasionally interact with the monsoon anticyclone and pull filaments of tropospheric air from its northern flank. These filaments, characterized by high values of humidity and low values of potential vorticity, can extend far north and transport moisture irreversibly into the northern hemisphere lower stratosphere. MOZAIC (Measurement of OZone by Airbus In‐service airCraft) data are used as an independent data source to validate the results obtained from the ECMWF analyses.
A mechanism relating tropical Atlantic spring sea surface temperature and west African rainfall
Authors: Zheng Xinyu , Eltahir Elfatih A. B. , Emanuel Kerry A.
Published: November 2010

In this paper, we describe a mechanistic study on the role of tropical Atlantic sea surface temperature (SST) variability in the dynamics of the west African monsoon. A hypothesis that a warm spring (April‐June) SST results in a wet monsoon is explored using a moist, zonally symmetric model. A positive spring rainfall anomaly has been simulated over the ocean, in response to the warm SST, which then propagates onto the land and persists two to three months, even after the SST anomaly vanishes. While the ocean‐atmosphere interaction is crucial for the initial development of the rainfall anomaly over land, the interactions between the ocean, land, and atmosphere are found to be important for relating tropical Atlantic spring SST to west African rainfall. Furthermore, the positive feedback between rainfall and soil moisture is responsible for some of the persistence in the rainfall anomaly. We present a case‐study for the wettest (1994) and driest (1992) years of the 1990s so far. The observations show that a warm spring SST anomaly in 1994 was associated with abundant summer rainfall over west Africa. These empirical observations are consistent with the proposed physical mechanism.
Kinematic characteristics of air flowing into and out of precipitating convection over the west Pacific warm pool: An airborne Doppler radar survey
Authors: Kingsmill David E. , Houze Robert A.
Published: November 2010

Air flowing into and out of 25 cloud systems over the west Pacific warm pool was sampled by Doppler radars on board two NOAA WP‐3D aircraft and the NCAR Electra aircraft during the Tropical Ocean/Global Atmosphere Coupled Ocean‐Atmosphere Response Experiment (TOGA‐COARE). In convective cells, updraught inflows and downdraught outflows tended to be positioned adjacent to each other at sharp updraught‐downdraught interfaces sloping at various angles and directions. The updraught inflows were sometimes shallow and sometimes deep, often extending well above the boundary layer. Downdraught outflow magnitudes were usually stronger than updraught inflows, and the horizontal directions of the inflow and outflow were frequently offset from each other at angles of ˜|90°|.

In stratiform precipitation regions, the dominant airflow features were descending mid‐level inflows, located at the bases of anvils and often extending into the interior of the precipitation system. These stratiform inflows originated at levels between 5 and 10 km and descended to about 3 km. A few extended down to the surface. Stratiform inflows were typically strong and sandwiched between weaker stratiform outflows at upper and lower altitudes. The stratiform‐region inflow and outflow directions were frequently offset by ˜|90°| in the horizontal. The mid‐level inflow currents entered the stratiform regions horizontally from a direction similar to that of the large‐scale ambient wind.

The mid‐level stratiform inflow tended to occur in the same vertical plane as the convective downdraught outflow, although the mid‐level stratiform inflow appeared to be slowed by horizontal pressure gradients before connecting with the convective downdraught outflow. In other respects, the mesoscale systems differed from a simplified two‐dimensional model of airflow. The systems moved primarily by discrete propagation, and updraughts and downdraughts tended to have orthogonal horizontal relative airflow.
The sensitivity of long‐wave radiation fields and the response of a GCM to water‐vapour continuum absorption
Authors: Wenyizhong  , Haigh Joanna D.
Published: November 2010

A wide‐band radiation model has been used to assess the impact of various models of the water‐vapour continuum on the infrared radiation fields of a three‐dimensional clear‐sky climatology and also on the climate of a general‐circulation model with fixed sea surface temperatures. The radiation model uses the emissivity method based on narrow‐band model and line‐by‐line transmittance calculations with four different continuum models: (a) a mainly window region, based on empirical fitting and ‘dimer’ method, (b) an implementation of the line‐wings method CKD‐0, (c) an implementation of the updated CKD version 2.2 and (d) CKD‐2.2 with a stronger temperature dependence in the window region based on aircraft and satellite measurements. The CKD methods decrease outgoing long‐wave radiation by about 5 W m‐2 and increase downward radiation at the surface by about 3.5 W m‐2 in the clear‐sky climatology. The difference between the CKD versions is less than 0.5 W m‐2 in both fields. The stronger temperature dependence causes only a small further decrease in outgoing long‐wave radiation but a further 2.5 W m‐2 in downward radiation at the surface. The spectral composition of all these changes, and its impact on the latitude‐height heating‐rate structure, is discussed. The changes in the radiation fields of the GCM are consistent with those shown in the clear‐sky climatology but the decrease in static stability, caused by the heating‐rate changes, results in modifications to the strength of the Hadley cells, mid‐latitude eddy heat transport, relative humidity and surface sensible and latent‐heat fluxes.
A generalized linear model approach to designing accelerated life test experiments
Authors: Monroe Eric M. , Pan Rong , Anderson‐Cook Christine M. , Montgomery Douglas C. , Borror Connie M.
Published: November 2010

Optimal experimental design practices are prominent in many applications. This paper proposes an alternate way of computing the information matrix, a key consideration in planning an accelerated life test. The generalized linear model approach allows optimal designs to be computed using iteratively weighted least‐square solutions versus a maximum likelihood method. This approach is demonstrated with an assumed exponential distribution and allows the practitioner to observe the underlying structure of the optimal experimental design matrix and its relationship to important factors such as censoring and a nonlinear response function. Optimality criteria are discussed for both parameter estimation and prediction variance at an intended usage condition, which is typically outside the feasible accelerated test region. Copyright © 2010 John Wiley & Sons, Ltd.
A model‐based approach for attribute gauge analysis
Authors: Vágó Emese , Kemény Sándor
Published: November 2010

A new method is proposed for the attribute gauge study. A mathematical model based on the Gauge Performance Curve (GPC) is introduced and the connection between the model parameters and gauge characteristics is discussed. The ability of the whole measurement system (the process and the gauge together) is characterized by two key probabilities: the probability of a rejected part being good and the probability of an accepted part being bad. These probabilities can be calculated either with the proposed mathematical model of GPC (GPC‐method) or by using relative frequencies (AIAG‐type method). The performance of the two approaches has been compared, and the proposed GPC‐method is proven to be statistically favourable. Copyright © 2010 John Wiley & Sons, Ltd.
Facile measurement of polymer film thickness ranging from nanometer to micrometer scale using atomic force microscopy
Authors: Hong Xiaodong , Gan Yang , Wang You
Published: November 2010

As many properties of polymer thin films critically depend on their thickness, a convenient and cost‐effective method for precise measurement of film thickness in a wide range is highly desirable. Here, we present a method which enables polymer film thickness, ranging from nanometer to micrometer scale, to be facilely determined by measuring the height of an artificially created film step on smooth substrates with atomic force microscopy (AFM). Three polymeric films (polystyrene, poly(methyl methacrylate) and poly(styrene–ethylene/butylene–styrene) films), spin‐coated on either mica or quartz substrate with thickness ranging from 5.7 nm to 4.4 µm, were employed to demonstrate the procedure and feasibility of our method. The proposed method is particularly suitable for thicker polymer films, thus complementing the traditional AFM ‘tip‐scratch’ method which is generally limited to polymer films of no more than 100 nm thickness. Copyright © 2010 John Wiley & Sons, Ltd.
Study on 172‐nm vacuum ultraviolet light surface modifications of polydimethylsiloxane for micro/nanofluidic applications
Authors: Yamamoto Takatoki
Published: November 2010

In this study, we developed a technique for modifying the surface of the silicone elastomer Poly(dimethylsiloxane) (PDMS) by 172‐nm wavelength vacuum ultraviolet (VUV) light exposure. Such materials have high potential for application to micro/nanofluidic devices if their surface properties can be adequately controlled. The hydrophilicity, zeta potential and bonding strength of the VUV‐exposed surfaces were investigated and compared to surfaces exposed to conventional vacuum oxygen plasma. It was found that the proposed technique was effective at modifying the surface conditions from hydrophobic to hydrophilic, increasing the zeta potential, and allowing good bonding to glass. The time required to produce the maximum bonding strength was found to be similar to that for vacuum oxygen plasma exposure. However, since VUV exposure does not require the creation of a vacuum, it offers a faster turnaround, making it suitable for mass production. Copyright © 2010 John Wiley & Sons, Ltd.
Effects of ionic environment on the interfacial interactions between α‐amylase and polyether sulphone membranes
Authors: Salgın Sema
Published: November 2010

This work reports a systematic study on the effects of ionic environment on the adsorption of α‐amylase on 30 kDa polyether sulphone (PES) membranes on the basis of interfacial interaction of PES membrane and α‐amylase enzyme in solution. Static adsorption of α‐amylase was investigated at the solution pH values of pH = 4.5, 5.6 and 7.0; and for the ionic strengths of 0.001, 0.01 and 0.1 M KCl. The maximum adsorption occurred at the pH value below the isoelectric point (IEP) of the enzyme, whereas the minimum adsorption occurred at the IEP (pH = 5.6) of amylase. With increasing ionic strength, the adsorbed enzyme on the membrane decreased. The Freundlich and Langmuir adsorption models were used for the mathematical description of the adsorption equilibrium and isotherm constants were evaluated depending on ionic environment. To determine the steps affecting the adsorption mechanism, the experimental data were evaluated using pseudo‐first‐order and pseudo‐second‐order kinetic models. The experimental data fitted well the pseudo‐first‐order kinetics. To detect the structural changes which occurred, membrane surfaces were analyzed by FTIR‐ATR spectroscopy. The effects of ionic environment on amylase activity were also investigated. Copyright © 2010 John Wiley & Sons, Ltd.
Parametric and comparative study of spandrel beam effect on the punching shear strength of reinforced concrete flat plates
Authors: Doh Jeung‐Hwan , Guan Hong , Kim Taewan
Published: November 2010

The safe and efficient construction of reinforced concrete flat plate systems requires an accurate, reliable and universally applicable procedure for the punching shear strength design. A nonlinear layered finite element method (LFEM) capable of analysing the punching shear strength of such system has been developed. Based on the LFEM, a parametric study is undertaken to evaluate some of the factors influencing punching shear strength of reinforced concrete flat palate with spandrel beams. This is done by varying the depth and the width of the spandrel beam while keeping other variables constant. The numerical results obtained by the LFEM are also compared with those predicted by the recommendations of the Australian Standard (AS3600‐2009) and the Wollongong‐Griffith (W‐G) semi‐empirical method. The results confirm that the Australian Standard is inadequate in predicting the punching shear strength at the corner and edge column connections of flat plates with spandrel beams or torsion strips. Copyright © 2010 John Wiley & Sons, Ltd.
Energy efficient MAC protocol for delay‐sensitive data transmission over wireless sensor network
Authors: Oh Hyung Rai , Song Hwangjun
Published: November 2010

This paper presents an energy efficient medium access control (MAC) protocol for delay‐sensitive data transmission over wireless sensor network. In general, energy consumption and delay depend on channel monitoring interval (CMI) and data sensing period at each sensor node. Based on this fact, we propose a new preamble structure to effectively advertise CMI and avoid the overhearing problem. In order to pursue an effective tradeoff between energy consumption and delay, we also develop a CMI determining algorithm that searches for a sub‐optimal solution with a low computational complexity in a distributive way. Finally, experimental results are provided to compare the proposed MAC protocol with existing sensor MAC protocols. Copyright © 2010 John Wiley & Sons, Ltd.
β‐Diketiminate Stabilized Magnesium Hydroxide, Heterobimetallic, and Halide Complexes: Synthesis and X‐ray Structural Studies
Authors: Nembenna Sharanappa , Singh Sanjay , Sen Sakya S. , Roesky Herbert W. , Ott Holger , Stalke Dietmar
Published: November 2010

The controlled hydrolysis of heteroleptic magnesium amide, LMgN(SiMe3)2 (L = CH[C(Me)N(2,6‐iPr2C6H3)]2) with water afforded the corresponding hydroxide [LMg(OH)·THF]2 as air and moisture sensitive compound. The presence of a sterically bulky β‐diketiminate ligand prevents the self‐condensation reaction of this hydroxide complex. Single crystal X‐ray analysis shows that the hydroxide is dimeric in the solid state. Reaction of the magnesium amide or LMg(Me)·OEt2 with LAlMe(OH) generates the heterobimetallic species containing the Mg–O–Al moiety. Additionally, the reaction of methylmagnesiumchloride with the free ligand leads to complex L′MgCl (L′ = CH[Et2NCH2CH2N(CMe)]2). As revealed by the crystal structure, L′MgCl is a solvent free monomeric magnesium chloride complex that is analogues to the Grignard reagent.
Economic Hardship, Neighborhood Context, and Parenting: Prospective Effects on Mexican–American Adolescent's Mental Health
Authors: Gonzales Nancy A. , Coxe Stefany , Roosa Mark W. , White Rebecca M. B. , Knight George P. , Zeiders Katharine H. , Saenz Delia
Published: November 2010

This study examined family and neighborhood influences relevant to low‐income status to determine how they combine to predict the parenting behaviors of Mexican–American mothers and fathers. The study also examined the role of parenting as a mediator of these contextual influences on adolescent internalizing and externalizing symptoms. Study hypotheses were examined in a diverse sample of Mexican–American families in which 750 mothers and 467 fathers reported on their own levels of parental warmth and harsh parenting. Family economic hardship, neighborhood familism values, and neighborhood risk indicators were all uniquely associated with maternal and paternal warmth, and maternal warmth mediated the effects of these contextual influences on adolescent externalizing symptoms in prospective analyses. Parents' subjective perceptions of neighborhood danger interacted with objective indicators of neighborhood disadvantage to influence maternal and paternal warmth. Neighborhood familism values had unique direct effects on adolescent externalizing symptoms in prospective analyses, after accounting for all other context and parenting effects.