bluuebunny/crossref_metadata_2025 huggingface dataset:
EXCITABLE SPIRAL WAVES IN NEMATIC LIQUID CRYSTALS
Authors: COULLET P. , PLAZA F.
Published: November 2004

A mechanical analog of the chemical and biological excitable medium is proposed. In nematic liquid crystals, the Freedericksz transition induced by a rotating tilted electric field provides a simple example of such a mechanical excitable system. We study this transition, derive a Ginzburg-Landau model for it, and show that the excitable spiral wave can be produced from a retractable finger-like soliton in this context.
SPATIOTEMPORAL GROWTH OF BACTERIAL COLONIES
Authors: GRIMSON MALCOLM J.
Published: November 2004

A continuum model for the spatiotemporal growth of bacterial colonies is introduced based on a coupled set of reaction-diffusion equations with local and nonlocal modes of colony growth. Local growth occurs where the colony is not close packed. Nonlocal growth occurs at the surface of a colony if local growth cannot account for the total amount of growth required by a global constraint. A model reaction scheme is used to extend the formalism to flux limited growth. In such cases a reaction zone within the colony is responsible for growth in both spherical colonies and biofilms. Modelling the growth of a bacterial colony on a flat solid surface requires anisotropy of the nonlocal growth component to be introduced.
RESONANCE EFFECTS FOR CHEMICAL REACTIVITY IN COMPLEX MEDIA
Authors: GAVEAU B. , MOREAU M.
Published: November 2004

We study the effect of the stochastic time variations of the environment on the reaction rate constant of an elementary chemical reaction. The reaction is modelled by a one-dimensional stochastic process, which can belong to a very broad class. The short-range fluctuating interactions between the reacting complex and the solvent molecules are simulated by dichotomous barriers obeying a Poisson process, which can hinder the process. Then we relate the overall reaction constant to the reaction constant of the pure reactive process, in the absence of the barriers. We give exact results in the case of one and two barriers, and a complete analysis of the overall reaction constant, or equivalently of the overall transmission probability of the system, is presented. In particular we show that, under certain conditions, a stochastic resonance occurs, in the sense that the transmission probability can be maximized by a convenient choice of the parameters of the barriers. In this case, the fluctuating barriers increase this transmission probability with respect to its value for the purely reactive process.
AN ADAPTIVE CONTROL ALGORITHM FOR TRACKING UNSTABLE PERIODIC ORBITS
Authors: PETROV VALERY , CROWLEY MICHAEL F. , SHOWALTER KENNETH
Published: November 2004

A predictor-corrector control algorithm for stabilizing and tracking unstable periodic orbits is presented. Automatic tracking is made possible by incorporating a stability-analysis subroutine into a map-based control scheme. The method is used to track unstable orbits in the Belousov-Zhabotinsky (BZ) reaction as a laboratory control parameter is varied.
OSCILLATORY INSTABILITIES IN BINARY MIXTURES FOR POSITIVE SEPARATION RATIO
Authors: FERNÁNDEZ-VELA J. , PÉREZ-GARCÍA C.
Published: November 2004

When a layer of a binary mixture with a positive Soret coefficient is heated from below, a pattern of stationary squares can be observed. When heating is increased, this planform loses stability and an alternation of squares and rolls appears in this case. Finally, when one enters in the so-called Rayleigh regime, rolls become stable. A part of this phenomenon is described by means of a heuristic model that includes the relevant physical modes of temperature and concentration in the particular case of a mixture with an infinite Prandtl number.
SYMMETRIC LARGE-SCALE VELOCITY FIELDS IN TWO-DIMENSIONAL THERMAL CONVECTION
Authors: PRAT J. , MERCADER I. , MASSAGUER J.M.
Published: November 2004

Recent experiments on thermal convection in finite containers [Krishnamurti & Howard, 1981; Howard & Krishnamurti, 1986] show the presence of flows spanning the largest dimension of the container. Numerical simulations of 2D thermal convection showing large-scale flows of this kind have been presented elsewhere [Prat et al., 1993a, 1993b]. In every known example the large scale velocity field has been found to display a vertical profile either antisymmetric or showing rather small departures from antisymmetry. In contrast, theoretical group arguments support the existence of symmetric velocity profiles. In the present paper it will be shown that large-scale velocity fields with vertically symmetric velocity profile do exist. In spite of these flows not being dominant in the range of parameters explored, their geometry and dynamics will be discussed on the basis of a linear stability analysis.
ANALYTICAL DESCRIPTION OF A FRACTAL SET GENERATED BY THE TIME-DELAYED CHUA’S CIRCUIT
Authors: KOCAREV L. , TASEV Z.
Published: November 2004

Using the thermodynamic formalism of Feigenbaum et al. [1986] we calculate the properties of a fractal set generated by a piecewise-linear one-dimensional map, introduced by Sharkovsky et al. [1993] in studying the time-delayed Chua’s circuit.
PREDICTING REGIMES OF INDETERMINATE JUMPS TO RESONANCE BY ASSESSING FRACTAL BOUNDARIES IN CONTROL SPACE
Authors: SOLIMAN MOHAMED S.
Published: November 2004

For nonlinear mechanical, structural and electrical systems, it is important to know, over a wide range of parameter values, whether jumps to resonance exist. Since the outcome may often be indeterminate, we have to identify parameters which place bounds on the determinancy of such jumps. Such an analysis is often quite complex since it involves determining both the main local and global bifurcations (the homoclinic and heteroclinic connections that induce a fractal basin structure at the bifurcation) that can lead to an indeterminate jump to resonance. Utilizing the fact that a sensitive dependence on the initial conditions implies a sensitive dependence on parameters, in this paper we propose a simplified method, based on assessing fractal boundaries in control space, that may be used to reveal aspects of indeterminate bifurcational behaviour of the system. Such an analysis which allows us to identify approximate regimes of indeterminate jumps to resonance, may either be used as an initial study for further detailed analysis, or as a simplified engineering approach in the analysis of systems liable to this type of resonant behaviour.
SYNCHRONIZATION BY FEEDBACK AND ADAPTIVE CONTROL
Authors: JOHN JOLLY K. , AMRITKAR R.E.
Published: November 2004

A feedback technique which synchronizes the phase space trajectory of a nonlinear dynamical system to a desired chaotic orbit is introduced. The same technique could be used to control the system to a desired unstable periodic orbit. The feedback which depends on the deviations of the variables from the desired orbit is given to a few of the system variables while the other variables evolve freely. This forces all the variables to synchronize with the corresponding variables of the desired orbit. It is further shown that an adaptive control together with the feedback technique could be used to synchronize the system to an unstable orbit. The system can recover from deviations introduced by sudden changes in the system parameter and the system synchronizes to the desired unstable orbit which may be chaotic. We demonstrate these ideas using the Lorenz system, Rössler system, and the resonant three-wave coupling equations from plasma physics.
THE ADDITIVITY OF CROSSING NUMBERS
Authors: DIAO YUANAN
Published: November 2004

It has long been conjectured that the crossing numbers of links are additive under the connected sum of links. This is a difficult problem in knot theory and has been open for more than 100 years. In fact, many questions of much weaker conditions are still open. For instance, it is not known whether Cr(K1#K2)≥Cr(K1) or Cr(K1#K2)≥Cr(K2) holds in general, here K1#K2 is the connected sum of K1 and K2 and Cr(K) stands for the crossing number of the link K. However, for alternating links K1 and K2, Cr(K1#K2)=Cr(K1)+Cr(K2) does hold. On the other hand, if K1 is an alternating link and K2 is any link, then we have Cr(K1#K2)≥Cr(K1). In this paper, we show that there exists a wide class of links over which the crossing number is additive under the connected sum operation. This class is different from the class of all alternating links. It includes all torus knots and many alternating links. Furthermore, if K1 is a connected sum of any given number of links from this class and K2 is a non-trivial knot, we prove that Cr(K1#K2)≥Cr(K1)+3.
THE NEXT SIMPLEST HYPERBOLIC KNOTS
Authors: CHAMPANERKAR ABHIJIT , KOFMAN ILYA , PATTERSON ERIC
Published: November 2004

We complete the project begun by Callahan, Dean and Weeks to identify all knots whose complements are in the SnapPea census of hyperbolic manifolds with seven or fewer tetrahedra. Many of these "simple" hyperbolic knots have high crossing number. We also compute their Jones polynomials.
LINK HOMOTOPY IN Sn×ℝm-n AND HIGHER ORDER μ-INVARIANTS
Authors: KOSCHORKE ULRICH
Published: November 2004

Given a suitable link map f into a manifold M, we constructed, in a previous publication, link homotopy invariants κ(f) and μ(f). In the present paper we study the case M=Sn×ℝm-n in detail. Here μ(f) turns out to be the starting term of a whole sequence μ(s)(f), s=0, 1,…, of higher μ-invariants which together capture all the information contained in κ(f). We discuss the geometric significance of these new invariants. In several instances we obtain complete classification results. A central ingredient of our approach is the homotopy theory of wedges of spheres.
SIMULATED PERFORMANCE OF ACOUSTIC TOMOGRAPHY VIA MATCHED FIELD PROCESSING
Authors: TOLSTOY A.
Published: November 2004

This paper examines the matched field tomographic approach when applied to the simulated data set designed by Chiu.1 The Chiu data set simulates a highly realistic, large (1000 km by 1000 km), deep ocean environment and was designed to serve as a test case for the comparison of various tomographic methods. Calculations show that: 1) the matched field method applied to each quarter of the region (500 km by 500 km) while deploying reasonable resources, e.g., four 1000 m long vertical arrays and a maximum of 174 shot sources, results in excellent accuracies, e.g., rms errors of approximately 0.5 m/sec at 300 m depth (the depth of maximum variability), and 2) these errors are relatively insensitive to expected errors in source and array location, and in source depth. We also find that resolution degrades, i.e. errors increase, as the number of sources decreases and also as source frequency decreases.
SURFACE STRUCTURAL RESEARCH WITH ATOM BEAM DIFFRACTION: HELIUM VERSUS NEON
Authors: RIEDER K.H.
Published: November 2004

A brief review on surface structural studies with He and Ne atom beam diffraction is presented. It is shown that for scattering from clean and hydrogen-covered metal surfaces with Ne, systematically larger corrugation amplitudes are obtained so that charge density contours closer to the surface atom cores are scanned. This leads to an enhanced sensitivity towards details of atomic arrangements at surfaces and sometimes surface bonding aspects can also be revealed. Most importantly, however, Ne seems to give more faithful pictures of surface atomic arrangements than He, probably due to larger influences of anticorrugating effects in He-metal surface interactions.
EFFECT OF van der WAALS FORCES ON ATOM-SURFACE SCATTERING
Authors: LEVI ANDREA C. , PASSERONE DANIELE
Published: November 2004

Besides generating the attractive well in the vicinity of a surface, van der Waals forces cause another interesting effect in atom-surface scasttering: they modify the phase of the atom along its semiclassical trajectory, determining thereby a very large scattering cross section from either adsorbed impurities or growth hillocks. Such effects are discussed and calculated in the framework of the hard-wall model for the unperturbed surface, and the results are compared with the experimental data obtained for CO on Pt by the Jülich group and for the Pd growth hillocks observed (in the form of truncated pyramids) on MgO by the Marseille group.
QUANTUM MECHANICS OF STICKING
Authors: KOHN W.
Published: November 2004

The sticking coefficient s(E) of an atom of low energy E striking a solid surface is discussed, with emphasis on the threshold behavior as E→0. The subject is under active experimental and theoretical study, which is summarized. There is general agreement that a classical treatment of the motion of the incident and target atoms yields s(E)→1 as E→0. This paper, in disagreement with the work by Th. Martin, R. Bruinsma, and P. Platzman, argues that, quantum mechanically, for small E, s(E)~E1/2 for neutral incident atoms and s(E)→ α(<1) for charged ones, regardless of the strength of the interaction. This behavior is due to (a) quantum reflection and (b) a Debye-Waller-like effect.
EVOLUTION OPERATOR AND ENERGY SPECTRUM OF A QUASICLASSICAL PARTICLE INTERACTING WITH BOSONS: APPLICATION TO ATOM SURFACE SCATTERING
Authors: GUMHALTER BRANKO , KIERON BURKE , LANGRETH DAVID C.
Published: November 2004

We investigate the properties of the interaction of a particle with a boson field describing the response of a solid in the limit in which the interaction matrix elements may be considered as quasiclassical and the particle-boson coupling linear but not necessarily weak. We start by expressing the evolution operator of the system in a convenient form of an exponentiated nested commutator expansion in powers of the interaction potential. From this we are able to estimate under which conditions on the particle motion the contributions of the higher order expansion terms become small, irrespective of the coupling strength. Neglecting such small terms in the exponent of the evolution operator, we can calculate the energy excitation spectrum characteristic of the coupled system or of any of its constituents (particle or boson field). These spectra have the appearance of an exponentiated Born approximation (EBA) which contains and interpolates smoothly between the more frequently used distorted wave Born approximation (DWBA) and the trajectory approximation (TA), thereby covering a wide range of the parameter space for the description of the particle-boson interaction dynamics. The shape of the spectra and their characteristics (the weight of the elastic line or the Debye-Waller factor (DWF), the mean number of excited bosons, and the mean energy transfer in the course of the interaction) are discussed and shown to be very sensitive to the (non)adiabaticity of the switching of the interaction and the magnitude of the particle mass M. In the case of nonadiabatic switching on (as e.g. in photoemission) and linear bosonic density of states, we retrieve in the limit M→∞ the familiar infrared threshold divergences in the spectrum of the system. In the opposite case of adiabatic switching rates typical of scattering, the spectra exhibit a well-defined elastic line and a finite DWF. The case of surface scattering is discussed in more detail for the example of neutral atom scattering from dispersionless surface phonons in atomic adlayers.
ATOMIC LEVEL STUDIES OF THE DYNAMICS AND DYNAMICAL BEHAVIOR OF SOLID SURFACES
Authors: TSONG TIEN T. , LO RONG-LI , CHANG TIEN-CHIH , CHEN CHONGLIN
Published: November 2004

Some of our recent results on the dynamics and dynamical behavior of atoms at metal surfaces are presented. Long range charge density oscillations due to chemisorbed impurities have been observed with the FIM. Two adatoms can interact with each other through mutual perturbation of the surface. This interaction is very weak, and exhibits a small but long range oscillatory tail. Surface self diffusion of adatoms can occur at about 1/10 to 1/5 the melting point of metals. This diffusion occurs by either atomic hopping or by atomic replacement-displacement. Diffusion of ledge atoms along a lattice step can occur at a similar temperature. At about 1/5 the melting point of a metal, dissociation of step edge atoms to terraces can occur and lattice steps can also start to roughen. Energetics of the atomic processes involved can be studied from their temperature dependences of their rates of occurrence and also from the densities of surface defects created. Recent progress in theoretical calculations makes it possible to compare them directly with experimental result, thus gaining insights into the dynamics in the dynamical behavior of metal surfaces.
ATOMIC STRUCTURE OF Si(113) 3×1-H BY DYNAMICAL LOW-ENERGY ELECTRON DIFFRACTION INTENSITY SPECTRA ANALYSIS
Authors: HUANG H. , TONG S.Y. , MYLER U. , JACOBI K.
Published: November 2004

The Si ((113) 3×1-H structure has been investigated by a quantitative low-energy electron diffraction intensity analysis. A model with two Si dimers in the unit cell gives best agreement between the calculation and the experimental data. Three-dimensional atomic coordinates have been determined.
The Si(111) $\sqrt 3 \times \sqrt 3 $ SURFACES FORMED BY THE ADSORPTION OF GROUP-III, IV, AND V METALS
Authors: KONO S.
Published: November 2004

A compilation of experimental studies is made on the properties of the Si(111) [Formula: see text] surfaces formed by the adsorption of metals of groups-III, IV, and V in the periodic table. The metals treated are Al, Ga, In (group-III), Sn, Pb (group-IV), Sb and Bi (group-V). Experimental studies using scanning tunneling microscopy are included only when they are necessary, since the topics will be covered in the review by J. Nogami in this issue. Theoretical aspects of the studies will be covered in the review by H. Nagayoshi in this issue.

The geometric and electronic properties of these Si(111) [Formula: see text] surfaces appeared to be the simplest kinds of surfaces on the Si(111), thus providing prototypic examples of reconstruction on the metal/Si submonolayer interfaces. The simplicity in these surfaces is that there are metal-adatoms over essentially truncated Si(111) 1×1 substrates. The types of "metal building-blocks" are basically two: (i) a single metal adatom on a threefold hollow site (so-called T4 site), (ii) a metal trimer, each of constituent atoms, resides nearly on the ontop site (so-called "milk-stool"). There is large relaxation in the substrate Si due to the presence of metal adatoms.
ELECTRONIC STRUCTURE OF THE Si(111) $\sqrt 3 \times \sqrt 3 $ SURFACES WITH GROUP-III, IV, AND V ADATOMS
Authors: NAGAYOSHI H.
Published: November 2004

A review is presented for the theoretical aspects of electronic structure and stable atomic geometry of group-III, IV, and V adatoms on the Si(111) surface. After summarizing the general concepts of surface electronic structure, we present preliminary studies based on the elementary theory of covalent bond, to understand the features of surface states and the relative stability of various candidates for adsorption geometries. Results of recent numerical calculations are then reviewed for three typical adatoms: Al, Sb, and B, in which we show how they give consistent conclusions with experimental findings.
ATOMIC GEOMETRY OF III-V SEMICONDUCTORS WITH Bi OVERLAYERS
Authors: UMERSKI A. , SRIVASTAVA G.P.
Published: November 2004

We use density functional theory (within the local density and pseudopotential approximations) to determine the equilibrium atomic positions of a number of III-V semiconductors with Bi overlayers. Our calculations are based on the complete self-consistent solution to the Kohn-Sham equations. The systems under consideration include GaAs(110), InP(110), and InAs(110) substrates, with zero, one, and two ordered monolayer coverages of Bi, within the Goddard (i.e., epitaxially continued) geometry. For the clean surfaces, our results compare well with existing LEED and X-ray standing wave analyses, as well as with recent Car-Parrinello type calculations. For the covered surfaces, we also obtain good agreement with any existing experimental observations. We find that the surface tilt angle of the clean surface systems is almost removed by the adsorption of a monolayer of Bi, and that the residual surface tilt angle can be related to the ionicity of the substrate.
THE INFLUENCE OF COADSORBATES (K, O) ON THE AUTOCATALYTIC DECOMPOSITION OF ACETIC ACID ON Rh{111}
Authors: PAPAGEORGOPOULOS D.C. , HOOGERS G. , KING D.A.
Published: November 2004

The autocatalytic decomposition of acetic acid has been studied with TPD on the Rh{111} surface with and without the presence of coadsorbates. Sharp H2 and CO 2 desorption peaks indicating autocatalytic processes are produced after saturating the surface with acetate, and also after coadsorption of oxygen and potassium at room temperature. Oxygen is found to stabilize the acetate; potassiun destabilizes the acetate, and O/K mixtures have an intermediate effect. The results are discussed in terms of a simple empty-site-creation autocatalytic mechanism for systems in which the surface is initially fully saturated with adsorbate species.
ARC Channels: A Novel Pathway for Receptor-Activated Calcium Entry
Authors: Shuttleworth Trevor J. , Thompson Jill L. , Mignen Olivier
Published: November 2004

In many nonexcitable cells, stimulation with low agonist concentrations specifically activates Ca2+entry via arachidonic acid-regulated, highly Ca2+-selective ARC channels. Only at high agonist concentrations are the more widely studied store-operated channels activated, producing sustained elevated cytosolic Ca2+concentration signals. These signals activate calcineurin, which in turn inhibits the ARC channels, resulting in a “reciprocal regulation” of these two distinct Ca2+-entry pathways that may have important functional implications for the cell.
Temporal and Spatial Variations in Structural Protein Expression During the Progression From Stunned to Hibernating Myocardium
Authors: Thijssen V.L.J.L. , Borgers M. , Lenders M.-H. , Ramaekers F.C.S. , Suzuki G. , Palka B. , Fallavollita J.A. , Thomas S.A. , Canty J.M.
Published: November 2004

Background—

Dysfunctional and normally perfused remote regions show equal myolysis and glycogen accumulation in pig hibernating myocardium. We tested the hypothesis that these arose secondary to elevations in preload rather than ischemia.

Methods and Results—

Expression of structural protein (desmin, desmoplakin, titin, cardiotin, α-smooth muscle actin, lamin-A/C, and lamin-B2) in viable dysfunctional myocardium was analyzed by immunohistochemistry. We performed blinded analysis of paired dysfunctional left anterior descending coronary artery and normal remote subendocardial samples from stunned (24 hours; n=6), and hibernating (2 weeks; n=6) myocardium versus sham controls pigs (n=7). Within 24 hours, cardiac myocytes globally reexpressed α-smooth muscle actin. In stunned myocardium, cardiotin was globally reduced, whereas reductions in desmin were restricted to the dysfunctional region. Alterations progressed with the transition to hibernating myocardium, in which desmin, cardiotin, and titin were globally reduced. A qualitatively similar reorganization of cytoskeletal proteins occurred 3 hours after transient elevation of left ventricular end-diastolic pressure to 33±3 mm Hg.

Conclusions—

Qualitative cardiomyocyte remodeling similar to that in humans with chronic hibernation occurs rapidly after a critical coronary stenosis is applied, as well as after transient elevations in left ventricular end-diastolic pressure in the absence of ischemia. Thus, reorganization of cytoskeletal proteins in patients with viable dysfunctional myocardium appears to reflect chronic and/or cyclical elevations in preload associated with episodes of spontaneous regional ischemia.
The Culture War Gone Global: ‘Family Values’ and the Shape of US Foreign Policy
Authors: Kline Scott
Published: November 2004

While ‘evil’ has long played a role in American civil-religious political discourse, there is a unique quality in the Bush administration’s framing of both its foreign and domestic policy in terms of a struggle between good and evil. This article examines the political and religious foundations underlying this framing. Three arguments shape the discussion. First, the Bush administration, following a political strategy influenced by neoconservatives and the religious right, has attempted to revive culture-war nationalism to define and defend American values. Second, when this strategy is coupled with an economic policy of free market capitalism, as is the case in the 2002 National Security Strategy, a paradox emerges between the conservative values of culture-war nationalism and the values associated with global capitalism. And, third, the Bush administration has at times been able to exploit the unease caused by this paradox to garner domestic political support. Such a strategy draws links between the domestic culture war and the global war on terror, revealing the influence of a political alliance between neoconservatives and the religious right in shaping the Bush administration’s understanding of evil in the twentyfirst century.
Forgiveness, the Unforgivable and International Relations
Authors: Digeser P. E.
Published: November 2004

This article turns to the idea of political forgiveness as one response to the temptation to eradicate or reject completely actors or regimes that are identified as evil. The possibility for forgiveness, however, hinges on the degree to which our identities are connected to our deeds. If our deeds are intimately connected to defining who we are, then loosening the idea of identity may help us evade the rejection-of-evil position. Derek Parfit’s reductionist perspective is used to make sense of such loosening at the level of individuals and regimes. Even if we believe that there are absolutely unforgivable acts the reductionist perspective may open the door to forgiveness and partially inoculate us from the temptation to reject evil-doers completely.
Optimization of the Micro-Injection Molding Process using Grey Relational Analysis and MoldFlow Analysis
Authors: Shen Y. K. , Chien H. W. , Lin Yi
Published: November 2004

Microsystem technology is a compound technology including optic, mechanism, electricity, material, control and chemistry, etc. This technology can miniaturize products and increase their function, quality, trustworthiness and addendum. Micro-injection molding is a branch of the micro-electro mechanical system. The size of the product is in nanometers. It is important to produce the product for micro-injection molding technology today. The research of micro-injection molding is still in the early stages. In this study, numerical simulations of three-dimensional micro-injection moldings were performed. The governing differential equations were described by using control volume finite element method. The analysis with different polymers (such as PP, PC, PS, POM) and process parameters (injection time, mold temperature, injection temperature, injection pressure) are used to simulate the microgear for example. In order to obtain optimum results, the simulation introduces the Taguchi method and grey relational analysis to discuss the influence of each parameter in microinjection molding. The results show that the PS material is the most suitable material used in this study. The results for Mold Flow analysis and grey relational analysis are the same on this study.
Comparative Party Finance Reform
Authors: Clift Ben , Fisher Justin
Published: November 2004

In Britain, the Political Parties, Elections and Referendums Act has revolutionized the regulation of party finance after several half-hearted failures at attempted reform. In France, a series of high-profile corruption scandals in the 1980s and 1990s provoked a bout of ‘legislative incontinence’ – resulting in over eight laws in seven years, which profoundly transformed the regime regulating party finance. The comparative analysis of reforms in each country presented here questions the utility of crude ‘constitutional engineering’ theories, and the notion of party system ‘cartelization’ by major parties, neither of which offers a wholly convincing account of the paths of reform in Britain and France. It explores the use of new institutionalist theories as a comparative framework and concludes that these provide a cogent explanation for the alternative paths taken by each country with party finance regulation.
Dystopian Travels in Gringolandia
Authors: Gutmann Matthew C.
Published: November 2004

This article examines the correlation between migration to the United States from Mexico, ethnicity, and changing gender relations among Mexicans on both sides of the international border. For example, the idea that Mexican society is homogenous and static, and therefore that only when they arrive in the United States do men and women from Mexico confront challenges to gender roles associated with traditionalism and patriarchy, is demonstrably false if nonetheless persistent. Using changing gender relations as illustrative of transformations associated more broadly with transnationalism, modernity, and ethnicity, I argue that an understanding of shifting relations between men and women as husbands and wives, sons and daughters, brothers and sisters, must be grounded in a rich knowledge of the changing conditions in the country of origin, Mexico, as well as the country of destination, the United States.
The Case of the Toothless Watchdog
Authors: Perry Timothy
Published: November 2004

Numerous scholars and activists have advocated a notion of language rights as a tool by which minority ethnic groups may protect their cultural integrity against the incursions of hegemonic groups. At the same time, critics have problematized language rights as a dangerous notion that may provoke inter-ethnic competition or worse. This article seeks to contribute to this debate a case study of the ‘rights mediation function’ of the Pan South African Language Board (PanSALB), a central component of South Africa’s uniquely progressive language rights framework. First, it is considered whether PanSALB’s support of ‘group’ language rights gives incentive to potentially divisive ethnic mobilization. Second, the efficacy and equitability of PanSALB’s service delivery is interrogated, as are the responses of the ruling African National Congress (ANC) to ethnolinguistic grievance. This article concludes that PanSALB does not give incentive to ethnic mobilization, but fails to protect language rights, and, as a structure, serves to co-opt civil society and help make ‘docile bodies’ of ordinary citizens.
Precompetence and trying to learn: Beginning writers talk about spelling
Authors: Martello Julie
Published: November 2004

This article explores some of the implications inherent in the pedagogical strategy of encouraging students to ‘try’ or ‘have a go’, particularly within the context of early writing and spelling. Pedagogical approaches built on the assumption that the learner will need to try in order to learn are construed here as emanating from and contributing to the construction of identities of ‘precompetence’ for students in the first years of school. The discussion of precompetence is contextualized within early literacy curriculum documents and practices in Australia and further examined through a functional linguistic analysis of two students’ talk about spelling strategies. The students’ explanations are marked by differences in the identity each learner constructs for herself and by differences in metalinguistic knowledge, suggesting possible links between the two. A rationale for the prevalence of encouraging students to try to spell is offered and supplementary approaches, based on the explicit teaching of spelling knowledge, are recommended.
Tailoring of Textile Preforms for Fibre-reinforced Polymer Composites
Authors: Ogale A. , Mitschang P.
Published: November 2004

The manufacturing of textile preforms is a well-established process for developing three-dimensional (3D) composite structures. The process of liquid composite molding (LCM) is an efficient method for the production of fibrereinforced polymer composite (FRPC) products. For the production of highperformance FRPCs, the sewn, the net shape, and ready-to-impregnate preforms are economically well suited in the LCM process [Mitschang, P., Ogale, A., Schlimbach, J., Weyrauch, F. and Weimer, C. (2003). Preform Technology: A Necessary Requirement for Quality Controlled LCM-processes, Polymers & Polymer Composites, 11(8): S. 605–622.]. Though the process of sewing has a long history, its usefulness in the area of composite manufacturing has not yet been fully exploited. The sewing technology, its associated parameters, required thread construction, and finally the stitch geometry are required to be considered thoroughly. Understanding the process of stitch formation and analysis of the available stitch geometries for preform stitching are the aims of this study. Various kinds of seams can be used in the preform development and structural assembling. The micrographic observations at the stitched zones help us to know the actual stitch geometry inside the FRPC structure, the amount of threads involved in each stitch type, the fibre displacement, and the structural properties. Furthermore, in order to widen the preform and the composite manufacturing practices, new technologies like single-sided-stitch, blind stitch, chain stitch, etc. are compared with the modified lock stitch. For structural reinforcements, the process-compatible carbon fibre thread, developed at the Institut fur Verbundwerkstoffe GmbH (IVW) has been explained in detail. In this paper, the usefulness of tailored preforming technology and process optimisation steps are described briefly.
Indications for endotracheal intubation and ventilation
Authors: Christian Steve , Manji Mav
Published: November 2004

The ability of the emergency physician to recognize and manage a patient with a compromised airway is probably the most important aspect of an individual’s care in the emergency department. Endotracheal intubation in a critically ill patient is a potentially hazardous procedure because of the technical difficulties that can be encountered during emergency airway management and the profound pathophy siological changes that the institution of mechanical ventilation can cause. This review article sets out to illustrate when invasive airway management should be considered and the potential consequences of attempts to perform endotracheal intubation and mechanical ventilation.
Assessment of the injured hand
Authors: Owers KL , Eckersley R
Published: November 2004

Hand injuries are common and often underestimated in terms of the structures damaged and potential loss of function if they are inappropriately managed. An accurate initial assessment, which includes a full history and clinical examination, will facilitate the optimum management and future outcome of such injuries. This article aims to give the clinician a methodical approach to this assessment based on the underlying anatomical structures and highlights some of the common pitfalls.
KIT and Platelet-Derived Growth Factor Receptor Alpha Tyrosine Kinase Gene Mutations and KIT Amplifications in Human Solid Tumors
Authors: Sihto Harri , Sarlomo-Rikala Maarit , Tynninen Olli , Tanner Minna , Andersson Leif C. , Franssila Kaarle , Nupponen Nina N. , Joensuu Heikki
Published: November 2004

Purpose

Mutated KIT and platelet-derived growth factor receptor alpha (PDGFRα) tyrosine kinases are the principal targets for imatinib mesylate in the treatment of gastrointestinal stromal tumors (GISTs). The frequency of activating KIT and PDGFRA gene mutations in most other histologic types of human cancer is not known.

Materials and Methods

KIT exons 9, 11, 13, and 17 and PDGFRA exons 11 and 17 of 334 human cancers were screened for mutations using sensitive denaturing high-performance liquid chromatography (DHPLC). In addition, all KIT exons from 9 to 21 of 115 tumors were screened. Thirty-two histologic tumor types were examined. Samples with abnormal findings in DHLPC were sequenced. Immunostaining for the KIT protein (CD117) was performed in 322 (96.4%) of the 334 cases.

Results

Of the 3,039 exons screened, only 17 had mutation. All 17 cases with either mutated KIT (n = 15) or PDGFRA (n = 2) were histologically GIST tumors, whereas none of the other histologic types of cancer (n = 316) harbored KIT or PDGFRA mutation. KIT immunostaining was rarely positive except in GISTs (18 of 18), small-cell lung cancer (10 of 30; 33%), and testicular teratocarcinoma (four of 17; 24%). Wild-type KIT gene amplification or chromosome 4 aneuploidy was common (seven of 12) in non-GIST tumors with strong KIT protein expression when studied with fluorescence in situ hybridization.

Conclusion

Despite frequent KIT protein expression in some tumor types, KIT and PDGFRA gene mutations are uncommon in most human cancers. Cancer KIT expression is frequently associated with multiple copies of the wild-type KIT gene.
Predicting the effects of blast loading arising from a pressure vessel failure: A review
Authors: Schleyer G. K.
Published: November 2004

An explosion resulting from a pressure vessel failure, during pressure testing or otherwise, could cause major damage to process plant and surrounding structures, not to mention injury to personnel. Thus, at the design stage or during pressure testing, loading and response data are required for risk assessment purposes and in order to make provision in the event of an incident. This review paper discusses commonly used simplified methods of predicting the effects of blast loading on ductile metallic structural components that could arise for example from the rupture of a gas-pressurized vessel, and is useful for engineers who lack any basic knowledge of blast loads and their effect on structures. It is assumed that the characteristics of the explosion source and blast wave have been previously estimated using, for example, the R3 impact assessment procedure.
Review of passive heat transfer augmentation techniques
Authors: Dewan A , Mahanta P , Raju K Sumithra , Kumar P Suresh
Published: November 2004

Heat transfer augmentation techniques (passive, active or a combination of passive and active methods) are commonly used in areas such as process industries, heating and cooling in evaporators, thermal power plants, air-conditioning equipment, refrigerators, radiators for space vehicles, automobiles, etc. Passive techniques, where inserts are used in the flow passage to augment the heat transfer rate, are advantageous compared with active techniques, because the insert manufacturing process is simple and these techniques can be easily employed in an existing heat exchanger. In design of compact heat exchangers, passive techniques of heat transfer augmentation can play an important role if a proper passive insert configuration can be selected according to the heat exchanger working condition (both flow and heat transfer conditions). In the past decade, several studies on the passive techniques of heat transfer augmentation have been reported. The present paper is a review on progress with the passive augmentation techniques in the recent past and will be useful to designers implementing passive augmentation techniques in heat exchange. Twisted tapes, wire coils, ribs, fins, dimples, etc., are the most commonly used passive heat transfer augmentation tools. In the present paper, emphasis is given to works dealing with twisted tapes and wire coils because, according to recent studies, these are known to be economic heat transfer augmentation tools. The former insert is found to be suitable in a laminar flow regime and the latter is suitable for turbulent flow. The thermohydraulic behaviour of an insert mainly depends on the flow conditions (laminar or turbulent) apart from the insert configurations. The present review is organized in five different sections: twisted tape in laminar flow; twisted tape in turbulent flow; wire coil in laminar flow; wire coil in turbulent flow; other inserts such as ribs, fins, dimples, etc.
Large eddy simulation of unsteady flows in turbomachinery
Authors: Lee S , Kim H-J , Runchal A
Published: November 2004

Unsteady computations of flows through a rotor of turbomachinery are very essential, and another challenge is to predict performances at off-design points, and to provide information on source fields as an input to the Ffowcs Williams-Hawkings (FW-H) equation for noise prediction. A deductive dynamic SGS modelling in large eddy simulation (LES) is proposed that does not impose averaging of the SGS model coefficients in homogeneous directions. This approach is tested and applied to the unsteady simulation of turbomachinery flow. The LES results from three typical cases of unsteady flows in turbomachinery, namely a NACA0018 airfoil, a compressor cascade and an axial fan, are reported. The flow characteristics on and around a symmetrical NACA0018 airfoil at moderate Reynolds number are simulated to establish the mechanism of discrete tone noise by unsteady flows near the trailing edge (TE) of the airfoil in a uniform flow. The flow past a compressor blade cascade is simulated to predict aerodynamic losses and self-noise by unsteady flows at off-design points. As a third example, the flowfields around rotating fan blades are simulated and used as an input to the FW-H equation to predict their farfield noise, which is in good agreement with experimental data.
Nonsense-mediated decay does not occur within the yeast nucleus
Authors: KUPERWASSER NICOLAS , BROGNA SAVERIO , DOWER KEN , ROSBASH MICHAEL
Published: November 2004

Nonsense-mediated decay (NMD) is a eukaryotic regulatory process that degrades mRNAs with premature termination codons (PTCs). Although NMD is a translation-dependent process, there is evidence from mammalian systems that PTC recognition and mRNA degradation takes place in association with nuclei. Consistent with this notion, degradation of mammalian PTC-containing mRNAs occurs when they are bound by the cap binding complex (CBC) during a “pioneer” round of translation. Moreover, there are reports indicating that a PTC can trigger other nuclear events such as alternative splicing, abnormal 3′ end processing, and accumulation of pre-mRNA at transcription sites. To examine whether a PTC can elicit similar nuclear events in yeast, we used RNA export-defective mutants to sequester mRNAs within nuclei. The results indicate that nuclear PTC-containing yeast RNAs are NMD insensitive. We also observed by fluorescent in situ hybridization that there was no PTC effect on mRNA accumulated at the site of transcription. Finally, we show that yeast NMD occurs minimally if at all on CBC-bound transcripts, arguing against a CBC-mediated pioneer round of translation in yeast. The data taken together indicate that there are no direct consequences of a PTC within the yeast nucleus.
Artificial tertiary motifs stabilize trans-cleaving hammerhead ribozymes under conditions of submillimolar divalent ions and high temperatures
Authors: SAKSMERPROME VANVIMON , ROYCHOWDHURY-SAHA MANAMI , JAYASENA SUMEDHA , KHVOROVA ANASTASIA , BURKE DONALD H.
Published: November 2004

Tertiary stabilizing motifs (TSMs) between terminal loops or internal bulges facilitate folding of natural hammerhead ribozymes (hRz) under physiological conditions. However, both substrate and enzyme strands contribute nucleotides to the TSMs of trans-cleaving hRz, complicating the design of hRz that exploit TSMs to target specific mRNA. To overcome this limitation, we used SELEX to identify new, artificial TSMs that are less sensitive to sequence context. Nucleotides in loop II or in a bulge within the ribozyme strand of stem I were randomized, while the interaction partner was held constant. All nucleotides of the substrate pair with the ribozyme, minimizing their possible recruitment into the TSM, as such recruitment could constrain choice of candidate target sequences. Six cycles of selection identified cis-acting ribozymes that were active in 100 μM MgCl2. The selected motifs partially recapitulate TSMs found in natural hRz, suggesting that the natural motifs are close to optimal for their respective contexts. Ribozyme “RzB” showed enhanced thermal stability by retaining trans-cleavage activity at 80°C in 10 mM MgCl2 and at 70°C in 2 mM MgCl2. A variant of ribozyme “RzB” with a continuously paired stem 1 rapidly lost activity as temperature was increased. The selected motifs are modular, in that they permit trans-cleavage of several substrates in submillimolar MgCl2, including two substrates derived from the U5 genomic region of HIV-1. The new, artificial tertiary stabilized hRz are thus nearly independent of sequence context and enable for the first time the use of highly active hRz targeting almost any mRNA at physiologically relevant magnesium concentrations.
Incommensurate modulations made visible by the Maximum Entropy Method in superspace
Authors: Palatinus Lukás , van Smaalen Sander
Published: November 2004

This paper presents the application of the Maximum Entropy Method (MEM) to structure solution of incommensurately modulated structures within the superspace formalism. The basic principles of the MEM are outlined, and its generalization toward superspace is discussed. Possible problems in MEM reconstructions and their solutions are summarized. They include series-termination errors in the reconstructed electron density, the effect of insufficient constraints, and the effect of missing data. The use of the MEM in superspace is illustrated by three examples: the structure of the misfit-layer compound (LaS)1.14NbS2, the structure of the high-pressure phase III of bismuth, and the modulated structure of ammonium tetrafluoroberyllate. It is shown that the MEM is able to extract more information about the modulation functions than can be obtained by structure refinements. The MEM can also be used for the study of accurate charge densities of modulated structures. An illustration is given by the charge density of ammonium tetrafluoroberyllate.
Genetic Variation for Total Fitness in Drosophila melanogaster
Authors: Gardner Michael P , Fowler Kevin , Barton Nicholas H , Partridge Linda
Published: November 2004

The extent of genetic variation in fitness is a crucial issue in evolutionary biology and yet remains largely unresolved. In Drosophila melanogaster, we have devised a method that allows the net effects on fitness of heterozygous wild-type chromosomes to be measured, by competing them against two different “balancer” chromosomes. We have applied the method to a large sample of 40 wild-type third chromosomes and have measured fitnesses of nonlethal chromosomes as well as chromosomes bearing recessive lethals. The measurements were made in the environment to which the population was adapted and did not involve inbreeding. The results show an extraordinary similarity in the behavior of replicates of the same chromosome, indicating consistent genetic effects on total fitness. Some invading chromosomes increased rapidly and some slowly, and some rose to appreciable frequency after several months, but then declined again: in every case, the same pattern was seen in each replicate. We estimated relative fitnesses, rates of change of fitness, and relative viabilities, for each chromosome. There were significant fluctuations around the fitted model, which were also highly replicable. Wild-type chromosomes varied substantially in their effects on heterozygous fitness, and these effects vary through time, most likely as a result of genotype × environment interactions.