bluuebunny/crossref_metadata_2025 huggingface dataset:
State-of-the-art and recent progress in phytoplankton succession modelling
Authors: Rigosi Anna , Fleenor William , Rueda Francisco
Published: February 2011

Dynamic phytoplankton succession models are an essential instrument to improve scientific knowledge on the development of algal blooms characterized by a specific composition and to support water quality management decisions. The peculiar structure and formulation of these models generate questions that differ from the ones found in modelling eutrophication and are related to simulation of multiple phytoplankton groups. In this work, a classification of phytoplankton models simulating several algal groups is provided. Coupled succession models, explicitly describing nonlinear interactions between physical and biological processes and capturing the response of phytoplankton community to environmental changes, are analyzed in detail. Approaches, actual achievements, and developments of succession models are examined. In particular, we discuss the level of discrimination adopted, number and type of algal groups simulated, biomass unit employed, type of model evaluation used, and efficacy of prediction achieved. Simulations of multiple phytoplankton group behaviour still produce significant deviations over time or in magnitude compared to the patterns observed. Frequently, goodness-of-fit estimation is only graphical and statistics adopted do not allow a direct comparison between different models. To facilitate comparisons we propose the use of a common statistic that would be applied, separately, to all the phytoplankton groups differentiated in each model. Each model’s level of complexity in relation to prediction ability is also analyzed. Through this work we aspire to orient upcoming works and encourage others to apply mechanistic succession models, including the description of physical and biological relationships, specific phytoplankton behaviour and interactions between phytoplankton groups.
Current state of genetically modified plant impact on target and non-target fungi
Authors: Stefani F. O.P. , Hamelin R. C.
Published: February 2011

For two decades, genetic engineering has made it possible to develop crops and trees designed for yield improvement and simplified culture management. This, combined with field deployment of monocultures over large areas, can result in environmental stress and unwanted potential side effects. The commercial production of genetically modified (GM) crops and the recent development of GM trees raise concerns about their potential impact on the environment, in general, and on the biodiversity of non-target organisms, in particular. Fungi are spread worldwide and play key roles in ecosystems. They have been closely associated with plants since they emerged from the oceans. This review critically examines research monitoring the potential effects of GM crops and GM trees on target and non-target fungi. Parsing public databases for peer-reviewed publications about GM plant impacts on fungi yielded 149 studies, a relatively modest number considering the diversity of crops and ecosystems studied. Analysis of these publications showed that the effects of GM plants expressing herbicide and insect tolerance on fungi are understudied while they dominate the GM area worldwide. Experiments monitoring the impact of GM crops and GM trees with enhanced antifungal activity towards target fungi showed, for the most part, significant decreases in disease severity caused by fungal pathogens. Significant changes, expressed as an increase or decrease in fungal development, abundance, and diversity of non-target fungi, were observed in 18 out of 60 studies and all of them involved GM plants expressing traits that were unexpected to affect fungi. The remaining 42 studies did not identify a significant impact on fungal populations. Therefore, in spite of the fact that GM plants have been commercialized since 1996, no clear generalized trend can be identified and it appears that a case-by-case approach is the safest.
NONLINEAR DIPOLE-EXCHANGE SURFACE SPIN WAVES ON FERROMAGNETIC MEDIA
Authors: XU YAN , TAN LEI , XING HUAI-ZHONG , ZHAO XIANG-DONG , LI FA-SHEN , ZHANG LU-YIN
Published: February 2011

Considering the inhomogeneous exchange anisotropy, the nonlinear surface spin waves in a dipole-exchange ferromagnetic media will be investigated. The total free energy of a dipole-exchange ferromagnet (FM) is given, and then the Landau–Lifshitz equation and the boundary conditions for a weakly nonlinear case are derived. The linear and nonlinear dispersion relations for dipole-exchange spin waves are given in a weak nonlinear approximation. The nonlinear Schrödinger equation, for the spin-wave envelope amplitude, is derived and its solitonic solution is discussed.
ANALYTIC ANALYSIS ON A GENERALIZED (2+1)-DIMENSIONAL VARIABLE-COEFFICIENT KORTEWEG–DE VRIES EQUATION USING SYMBOLIC COMPUTATION
Authors: ZHANG CHENG , TIAN BO , LI LI-LI , XU TAO
Published: February 2011

With the help of symbolic computation, a generalized (2+1)-dimensional variable-coefficient Korteweg–de Vries equation is studied for its Painlevé integrability. Then, Hirota bilinear form is derived, from which the one- and two-solitary-wave solutions with the corresponding graphic illustration are presented. Furthermore, a bilinear auto-Bäcklund transformation is constructed and the nonlinear superposition formula and Lax pair are also obtained. Finally, the analytic solution in the Wronskian form is constructed and proved by direct substitution into the bilinear equation.
ELECTRICAL RESISTIVITY OF AMORPHOUS Fe AND Ni
Authors: ZIAUDDIN AHMED A. Z. , BHUIYAN G. M. , ALAM M. S. , RANA M. M. , RASHID R. I. M. A.
Published: February 2011

We have calculated the electrical resistivity of amorphous transition metals Fe and Ni by using the Diffraction model as proposed by Ziman. The electron–ion interaction is described by a local model pseudopotential, and the static structure factors are taken from the experiment. The d-band effect, a characteristic of the transition metals, is accounted for through the sp–d hybridization effect. Agreement of the calculated results with the available experimental data is found to be remarkably good for both systems.
A TYPE OF SINGLE SCROLL ATTRACTOR CHAOS SYNCHRONIZATION
Authors: WANG TIANSHU , WANG XINGYUAN
Published: February 2011

This paper studies a type of single scroll attractor chaos system. Based on the research of Jiang et al. the global synchronization method is designed, and moreover, the author uses a combined synchronization of linear and nonlinear feedback, active control, single vector and unidirectional coupling synchronization three methods else, the problem of synchronization between same and different chaotic systems are realized by the four methods, respectively. The range of control function parameter is discussed according to the Routh–Hurwitz criterion and numerical simulations show the effectiveness of them.
CURRENT CONDUCTION MECHANISMS OF ATOMIC-LAYER-DEPOSITED Al2O3/NITRIDED SiO2 STACKING GATE OXIDE ON 4H-SiC
Authors: CHEONG K. Y. , LOCKMAN Z. , AZIZ A. , MOON J. H. , KIM H. J. , BAHNG W. , KIM N.-K. , HASSAN Z.
Published: February 2011

Current conduction mechanisms of atomic-layer deposited Al 2 O 3 (13 nm) stacked on different thermal nitrided SiO 2 thicknesses (2, 4, and 6 nm) on n-type 4 H-SiC have been systematically analyzed. It has been observed that the oxides were thermally stable at the investigated temperature range (25–140°C). By using different conduction process models, such as Schottky emission, direct tunneling, Fowler–Nordheim tunneling, Poole–Frenkel emission, and space-charge limited conduction, which consists of three limited conduction processes, namely, Ohm's law, Child's law, and trap-filled limit, the conduction mechanisms of charge through the oxides have been evaluated. It has been found that the conduction mechanisms were not affected by the investigated temperature range. A relationship plot has been proposed among nitrided SiO 2 thickness, electric field, and conduction mechanisms.
PREPARATION AND STRUCTURAL CHARACTERIZATION OF NANOCRYSTALLINE Zn–Cu–Cr FERRITES WITH Gd SUBSTITUTION
Authors: JIANG JING , CHEN CHAOCHAO , AI LUNHONG
Published: February 2011

Nanocrystalline spinel Zn – Cu – Cr ferrites with Gd substitution were prepared by a rheological phase reaction method. By means of the Fourier transform infrared (FTIR) spectra, Raman spectra, and X-ray diffraction (XRD), the cubic spinel structure of samples had been confirmed. The magnetic parameters such as saturation magnetization, remanent magnetization and coercivity can be tailored by controlling the content of substituting Gd ions.
ONE-DIMENSIONAL QUANTUM TRANSVERSE-FIELD ISING MODEL: A SEMICLASSICAL TRANSFER MATRIX APPROACH
Authors: KAYA TUNCER
Published: February 2011

In this work we present a semi-classical transfer matrix method to study one-dimensional modified quantum transverse-field Ising model. Both average magnetization per spin along the z-direction 〈σz〉 and along the x-direction 〈σx〉 are calculated in this picture. It is predicted that the t > 1 case is the corresponding effective ferromagnetic phase [Formula: see text] at sufficiently high Hzwhereas t < 1 case is an effective paramagnetic phase [Formula: see text]. Consequently, it is concluded that t = Hz/K = 1, here Hzis the transverse field along the z-axis and K is the coupling strength, which corresponds to quantum ferromagnetic-paramagnetic phase transition. In other words, the same result of the sophisticated quantum field theoretical calculation is predicted unexpectedly in the naive semiclassical picture.
EXACT ANALYTICAL EXPRESSIONS AND NUMERICAL VALUES OF SLATER'S AND MARVIN'S RADIAL INTEGRALS OF THE TYPE $R_k^{(\mu, \nu)} (11, 21; 12, 22)$, $F_k^{(\mu, \nu)} (1, 2)$ AND $G_k^{(\mu, \nu)} (1; 2)$ WITH THE KERNEL $r_<^{k+\mu}/r_>^{k+\nu}$ (AS k ≥ 0, μ ≥ 0 IS AN EVEN AND ν - μ = 1, 3, 5, …) FOR ARBITRARY nl-STATES OF H-LIKE ATOMS AND Z ≤ 137 BY MEANS OF APPELL'S F2(x, y) AND GAUSS'S 2F1(z) FUNCTIONS
Authors: TARASOV V. F.
Published: February 2011

This article deals with the connection between a.m. the hydrogenic radial integrals in the theory of atomic spectra and new properties of Appell's function F2(x, y) to the vicinity of the singular point (1, 1) and to the domain |x|+|y| < 1. In Tables 1–7 exact numerical values of these integrals are first given, i.e., actually for all Mendeleev's table. (Author has all values these of integrals for arbitrary nl-states of H-like atoms, k ≥ 0 and Z ≤ 137).
INTEGRABLE COUPLINGS OF MULTI-COMPONENT AKNS–KAUP–NEWELL EQUATIONS HIERARCHIES
Authors: ZHANG JIAN-BING , JI JIE , CHEN DENG-YUAN
Published: February 2011

In this paper, hierarchies of multi-component AKNS–Kaup–Newell equations are derived, including positive nonisospectral AKNS–Kaup–Newell hierarchy and negative nonisospectral AKNS–Kaup–Newell hierarchy. Moreover, new integrable couplings of the resulting AKNS–Kaup–Newell soliton hierarchies are constructed by enlarging the associated matrix spectral problem.
POSSIBLE EXISTENCE OF GRANULAR LEFT-HANDED MATERIALS BASED ON BRUGGEMAN FORMALISM
Authors: XU WEIKAI , DONG YANZHANG , LIU SHUTIAN
Published: February 2011

In the current stage, left-handed material (LHM) has aroused wide interest based on several basic prototypes such as metamaterials. In this work, we have theoretically investigated the possible existence of granular LHM by using the Bruggeman formalism. The Wiener bounds and the Hashin–Shtrikman bounds were invoked and some examples were represented. We had found that when the dissipations are increased adequately, the estimates of the Bruggeman formalism will lie within the two bounds rigorously, even if the two permittivities have real parts of opposite signs. Thus, one particulate LHM may be achieved by choosing the two component mediums with negative permittivity and negative permeability, respectively.
FIXATION TIME FOR EVOLUTIONARY GRAPHS
Authors: NIE PU-YAN , ZHANG PEI-AI
Published: February 2011

Evolutionary graph theory (EGT) is recently proposed by Lieberman et al. in 2005. EGT is successful for explaining biological evolution and some social phenomena. It is extremely important to consider the time of fixation for EGT in many practical problems, including evolutionary theory and the evolution of cooperation. This study characterizes the time to asymptotically reach fixation.
EMERGING STRUCTURES IN SOCIAL NETWORKS GUIDED BY OPINIONS' EXCHANGES
Authors: CARLETTI TIMOTEO , RIGHI SIMONE , FANELLI DUCCIO
Published: February 2011

In this paper, we show that the small world and weak ties phenomena can spontaneously emerge in a social network of interacting agents. This dynamics is simulated in the framework of a simplified model of opinion diffusion in an evolving social network where agents are made to interact, possibly update their beliefs and modify the social relationships according to the opinion exchange.
ON THE APPLICATION OF THE CROSS-CORRELATIONS IN THE CHINESE FUND MARKET: DESCRIPTIVE PROPERTIES AND SCALING BEHAVIORS
Authors: DENG WEIBING , LI WEI , CAI XU , WANG QIUPING A.
Published: February 2011

On the basis of the relative daily logarithmic returns of 88 different funds in the Chinese fund market (CFM) from June 2005 to October 2009, we construct the cross-correlation matrix of the CFM. It is shown that the logarithmic returns follow an exponential distribution, which is commonly shared by some emerging markets. We hereby analyze the statistical properties of the cross-correlation coefficients in different time periods, such as the distribution, the mean value, the standard deviation, the skewness and the kurtosis. By using the method of the scaled factorial moment, we observe the intermittence phenomenon in the distribution of the cross-correlation coefficients. Also by employing the random matrix theory (RMT), we find a few isolated large eigenvalues of the cross-correlation matrix, and the distribution of eigenvalues exhibits the power-law tails. Furthermore, we study the features of the correlation strength with a simple definition.
TURNOUT INTENTION AND RANDOM SOCIAL NETWORKS
Authors: FOSCO CONSTANZA , LARUELLE ANNICK , SÁNCHEZ ANGEL
Published: February 2011

How can networking affect the turnout in an election? We present a simple model to explain turnout as a result of a dynamic process of formation of the intention to vote within Erdös–Rényi networks. Citizens have fixed preferences for one of two parties and are embedded in a social network. They decide whether or not to vote on the basis of the attitude of their immediate contacts. They may simply follow the behavior of the majority (followers) or make an adaptive local calculus of voting (calculators). So they have the intention of voting either when the majority of their neighbors are willing to vote too, or when they perceive in their social neighborhood that elections are "close". We study the long-run average intention to vote, interpreted as the actual turnout observed in an election. Depending on the values of the average connectivity and the probability of behaving as a follower/calculator, the system exhibits monostability (zero turnout), bistability (zero and moderate/high turnout) or tristability (zero, moderate and high turnout). By obtaining realistic turnout rates for a wide range of values of both parameters, our model suggests a mechanism behind the observed relevance of social networks in recent elections.
Automated termination proofs for haskell by term rewriting
Authors: Giesl Jürgen , Raffelsieper Matthias , Schneider-Kamp Peter , Swiderski Stephan , Thiemann René
Published: February 2011

There are many powerful techniques for automated termination analysis of term rewriting. However, up to now they have hardly been used for real programming languages. We present a new approach which permits the application of existing techniques from term rewriting to prove termination of most functions defined in Haskell programs. In particular, we show how termination techniques for ordinary rewriting can be used to handle those features of Haskell which are missing in term rewriting (e.g., lazy evaluation, polymorphic types, and higher-order functions). We implemented our results in the termination prover AProVE and successfully evaluated them on existing Haskell libraries.
Miss Grant's controller
Authors: Ferg Stephen
Published: February 2011

Traditional computer specifications focus on states and state transitions. In contrast, Jackson System Development (JSD) focuses on events and the sequence in which events may occur. I present an argument-by-example for JSD-style event-oriented specifications and show that Python can be used to create executable JSD specifications.
Design patterns detection using SOP expressions for graphs
Authors: Gupta Manjari , Pande Akshara , Tripathi A. K.
Published: February 2011

Several recurring patterns of classes exist in many object oriented software as an experience of developers. Design Pattern Detection is an important part of many solutions to Software Reuse practices. Design pattern instances are highly important and useful for program understanding and software maintenance. Hence an automatic and reliable design pattern mining capability is required. Here we are proposing a new method for design pattern detection based on Boolean functions.
Improving tests infrastructure through a model-based approach
Authors: Pinel Roque Elias Assumpção , do Carmo Filipe Braida , Monteiro Rodrigo Salvador , Zimbrão Geraldo
Published: February 2011

Software tests have a high impact on the cost of software development. In practice, they are generally created at random and without any methodology, and do not have sufficient documentation. Commonly used approaches also perform the tests outside the application environment (e.g. web servers and containers). Besides, the test cases are usually restricted to target business components behavior, leaving a huge gap by not evaluating the presentation layer. Most of these practices can be explained by the overhead required to maintain manually the whole test artifacts. Applying a Model-based Approach (MBA), the creation and maintenance of test artifacts can be automated. This paper proposes a method that applies the Model-driven Architecture (MDA), a strategy of MBA, to determine the flow of test cases. The proposed method was based on the use of Unified Modeling Language (UML) activity diagrams. These diagrams allow determining the test flows and the objective of each activity, such as testing of business and presentation layers. Moreover, the generated test artifacts allow for performing the tests inside the application environment.
Natural language based component extraction from requirement engineering document and its complexity analysis
Authors: Sharma Ashish , Kushwaha Dharmender Singh
Published: February 2011

Requirement engineering document (IEEE-830: 1998) plays a very significant role in software development. The size and complexity of software systems are continuously increasing. As scale changes to more complex and larger systems, new problems occur that did not exist in smaller systems This leads to redefining priorities of the activities that go into developing software. As systems ges complex, it becomes evident that the goals of the entire system can't be easily comprehended. Hence the need of more rigorous requirement analysis arises. The requirement analyst has to identify the requirements by using various methods like interviews, brainstorming, FAST (facilitated application specification techniques), quality function deployment, use-case etc. To overcome these issues, this paper proposes object based semi-automated system that categorize the requirements and further identifies the component based on requirement engineering document in a component library and further analyses the complexity of components and its usage.
Static analysis by abstract interpretation of embedded critical software
Authors: Julien Bertrane Julien , Cousot Patrick , Cousot Radhia , Feret Jérôme , Mauborgne Laurent , Miné Antoine , Rival Xavier
Published: February 2011

Formal methods are increasingly used to help ensuring the correctness of complex, critical embedded software systems. We show how sound semantic static analyses based on Abstract Interpretation may be used to check properties at various levels of a software design: from high level models to low level binary code. After a short introduction to the Abstract Interpretation theory, we present a few current applications: checking for run-time errors at the C level, translation validation from C to assembly, and analyzing SAO models of communicating synchronous systems with imperfect clocks. We conclude by briey proposing some requirements to apply Abstract Interpretation to modeling languages such as UML.
QVT-based model transformation using XSLT
Authors: Li Dan , Li Xiaoshan , Stolz Volker
Published: February 2011

Model transformations are one of the key technologies in modelbased development. The graphical notation of relational QVT provides a concise, intuitive way to specify transformations. But this notation is not directly applicable for practitioners because of the lack of tool support. On the other hand, XSLT is a common and powerful language for XML transformations, but not suitable for directly programming transformations of semantically complex models due to its low level syntax. We combine the best of both techniques by using QVT graphical notation to specify a transformation as a set of QVT relations, and implementing each relation as an XSLT rule template. A prototype tool with a QVT graphical editor and an automatic XSLT program generator has been developed to support the approach.
Dynamic antenna mode selection for link maintenances in mobile ad hoc network
Authors: Kumar P. Shiva , Sharma Rinki , Varaprasad G.
Published: February 2011

Mobile ad hoc networks are designed to work in environments, where the terrains have unpredictable obstacles such as hills, water bodies, buildings or regions without any nodes. In the mobile ad hoc network, the mobile nodes use the directional antennas to achieve high spatial reuse. If the nodes with the directional beam move, then the obstacles may come between the communicating nodes. The link quality deteriorates resulting in link break, causing disruption in the communication. This paper proposes a scheme, which allows the mobile nodes to maintain the link in an irregular terrain by dynamically changing antenna mode from directional to omni. The proposed model has been simulated using Qualnet simulator (version 4.5). The simulation results shown that the proposed model is improved the network performance in terms of packet delivery ratio, number of link breaks and number of hops.
Cache complexity and multicore implementation for univariate real root isolation
Authors: Chen Changno , Maza Marc Moreno , Xie Yuzhen
Published: February 2011

Isolating the real roots of a univariate polynomial is a driving subject in computer algebra. This problem has been studied under various angles from algebraic algorithms [1, 2, 7] to implementation techniques [3, 5]. Today, multicores are the most popular parallel hardware architectures. Beside, understanding the implications of hierarchical memory on performance software engineering has become essential. These observations motivate our study. We analyze the cache complexity of the core routine of many real root isolation algorithms namely, the Taylor shift. Then, we present efficient multithreaded implementation on multicores.
Optimization techniques for small matrix multiplication
Authors: Drevet Charles Éric , Islam Md. Nazrul , Schost Éric
Published: February 2011

We tabulate improved costs for the multiplication of matrices of small size, up to 30. Following previous work by Probert &Fisc her [5], Smith [4], and Mezzarobba [2], we base our approach on previous algorithms for small matrices due to Strassen, Winograd, Pan, Laderman, . . . and show how to exploit these standard algorithms in an improved way. We illustrate the use of our results by generating multiplication code for various rings, such as integers, polynomials, differential operators or linear recurrence operators.
Non-commutative subsystems of singular
Authors: Levandovskyy Viktor
Published: February 2011

We describe the state-of-the-art of non-commutative subsystems of computer algebra system Singular, both already released and under preparations for release. The classes of algebras, functionality over them, primary application fields of subsystems are explained in details.
Sturm root counting using chebyshev expansion
Authors: Murakami Hiroshi
Published: February 2011

The Sturm's root counting method by the floating point calculation was studied to solve real roots of a real algebraic equation of high degree. To reduce the effects of round-off errors, polynomials are represented by the coefficients of Chebyshev polynomials instead of monomials. In the Sturm sequence calculation, the quotients are stored instead of remainders. The values of remainders at a given abscissa to count their sign variations are calculated from the stored sequence of quotients. This approach reduces the space and the number of arithmetic operations. Some experiments was made using the FP numbers.
Linear differential implicitization and differential resultants
Authors: Rueda Sonia L.
Published: February 2011

Given a system
P
of
n
linear ordinary differential polynomial parametric equations (linear DPPEs) in
n
-1 differential parameters, we proved in [2] that if nonzero a differential resultant gives the implicit equation of
P
. Differential resultants often vanish under specialization, which prevented us from giving an implicitization algorithm in [2]. Motivated by Canny's method and its generalizations we consider now a linear perturbation of
P
and use it to give an algorithm to decide if the dimension of the implicit ideal of
P
is
n
-1 and in the affirmative case obtain the implicit equation of
P
. This poster presentation will contain this development together with examples illustrating the results. An extended version of this work can be found in [1].
A FPGA implementation of Chen's algorithm
Authors: Saouter Yannick , Le Mestre Gérald
Published: February 2011

This article is devoted to describing an implementation of Chen's algorithm on FPGA. This algorithm allows the computation of minimum distance of cyclic codes. As an application, we determine the minimum distance of quadratic residue codes of length 223.
Differential schemes
Authors: Bardavid Colas
Published: February 2011

This thesis focuses on the theory --- still under construction --- of differential schemes. The aim of our work is to provide two new perspectives to this theory.

The first perspective is geometric and consists in considering schemes endowed with vector fields instead of differential rings. In this context, we define what is a leaf and what is the trajectory of a point. With the help of these tools, we reinvest and generalize some results of differential Galois theory. Similarly, we show that the Carrà Ferro sheaf is the natural sheaf of the space of leaves of a scheme with vector field. It is also this approach that lead us to prove that, in the reduced case, the Kovacic and Keigher sheaves are isomorphic and that they have the same constant as the Carrà Ferro sheaf.

The second perspective is functorial, and is based on the notion of scheme due to Toën and Vaquié [6]. We prove that the category of differential schemes in the sense similar to the one of these authors is equivalent to the category of schemes endowed with a vector field.
Exact solutions to linear systems of equations using output sensitive lifting
Authors: Steffy Daniel E.
Published: February 2011

Many methods have been developed to symbolically solve systems of linear equations over the rational numbers. A common approach is to use p-adic lifting or iterative refinement to build a modular or approximate solution, then apply rational number reconstruction. An upper bound can be computed on the number of iterations these algorithms must perform before applying rational reconstruction. In practice such bounds can be conservative. Output sensitive lifting is the technique of performing rational reconstruction at intermediate steps of the algorithm and verifying correctness which allows the possibility of early termination when the solution size is small. In this paper we show how using an appropriate output sensitive lifting strategy can improve several algorithms. We show this procedure to be computationally effective and introduce a variant of the iterative-refinement method that incorporates warm starts into the rational reconstruction procedure.
simpcomp
Authors: Effenberger Felix , Spreer Jonathan
Published: February 2011

simpcomp [4] is an extension (a so called package) to GAP [6], the well known system for computational discrete algebra. The package enables the user to compute numerous properties of (abstract) simplicial complexes, provides functions to construct new complexes from existing ones and an extensive library of triangulations of manifolds. For an introduction to the field of piecewise linear (PL) topology see the books [16] and [11].

The authors acknowledge support by the DFG: simpcomp has partly been developed within the DFG projects Ku 1203/5-2 and Ku 1203/5-3.
TRIP
Authors: Gastineau Mickaël , Laskar Jacques
Published: February 2011

TRIP is an interactive computer algebra system that is devoted to perturbation series computations, and specially adapted to celestial mechanics. Its development started in 1988, as an upgrade of the special purpose FORTRAN routines elaborated by J. Laskar for the demonstration of the chaotic behavior of the Solar System. TRIP is now a mature and efficient tool for handling multivariate generalized power series, and contains also a numerical kernel. A limited version of TRIP is freely available on the WEB at www.imcce.fr/trip.
LocalizeRingForHomalg
Authors: Barakat Mohamed , Lange-Hegermann Markus
Published: February 2011

The objective of this software presentation is to demonstrate a means of homological computation of finitely presented modules over a commutative ring
R
localized at a maximal ideal m. This can be achieved by a reduction of the problem of solving linear systems over
R
m
to the same problem over
R
. An implementation in the GAP-package LocalizeRingForHomalg exists as a part of the homalg project.
Sparse polynomial multiplication and division in Maple 14
Authors: Monagan Michael , Pearce Roman
Published: February 2011

We demonstrate new routines for sparse multivariate polynomial multiplication and division over the integers that we have integrated into Maple 14 through the expand and divide commands. These routines are currently the fastest available, and the multiplication routine is parallelized with superlinear speedup. The performance of Maple is significantly improved. We describe our polynomial data structure and compare it with Maple's. Then we present benchmarks comparing Maple 14 with Maple 13, Magma, Mathematica, Singular, Pari, and Trip.
Linear differential, difference and
q
-difference homogeneous equations having no rational solutions
Authors: Gheffar A.
Published: February 2011

Some changes of the traditional scheme for finding rational solutions of linear differential, difference and
q
-difference homogeneous equations with rational coefficients are proposed. In many cases these changes allow one to predict the absence of rational solutions in an early stage of the computation.
Interface Physics in Complex Oxide Heterostructures
Authors: Zubko Pavlo , Gariglio Stefano , Gabay Marc , Ghosez Philippe , Triscone Jean-Marc
Published: February 2011

Complex transition metal oxides span a wide range of crystalline structures and play host to an incredible variety of physical phenomena. High dielectric permittivities, piezo-, pyro-, and ferroelectricity are just a few of the functionalities offered by this class of materials, while the potential for applications of the more exotic properties like high temperature superconductivity and colossal magnetoresistance is still waiting to be fully exploited. With recent advances in deposition techniques, the structural quality of oxide heterostructures now rivals that of the best conventional semiconductors, taking oxide electronics to a new level. Such heterostructures have enabled the fabrication of artificial multifunctional materials. At the same time they have exposed a wealth of phenomena at the boundaries where compounds with different structural instabilities and electronic properties meet, giving unprecedented access to new physics emerging at oxide interfaces. Here we highlight some of these exciting new interface phenomena.
Deformation and Failure of Amorphous, Solidlike Materials
Authors: Falk Michael L. , Langer J.S.
Published: February 2011

Since the 1970s, theories of deformation and failure of amorphous, solidlike materials have started with models in which stress-driven, molecular rearrangements occur at localized flow defects via shear transformations. This picture is the basis for the modern theory of shear transformation zones (STZs), which is the focus of this review. We begin by describing the structure of the theory in general terms and by showing several applications, specifically, interpretation of stress-strain measurements for a bulk metallic glass, analysis of numerical simulations of shear banding, and the use of the STZ equations of motion in free-boundary calculations. In the second half of this review, we focus for simplicity on what we call an athermal model of amorphous plasticity, and use that model to illustrate how the STZ theory emerges within a systematic formulation of nonequilibrium thermodynamics.
Electron Glass Dynamics
Authors: Amir Ariel , Oreg Yuval , Imry Yoseph
Published: February 2011

Examples of glasses are abundant, yet it remains one of the phases of matter whose understanding is very elusive. In recent years, remarkable experiments have been performed on the dynamical aspects of glasses. Electron glasses offer a particularly good example of the trademarks of glassy behavior, such as aging and slow relaxations. In this work we review the experimental literature on electron glasses, as well as the local mean-field theoretical framework put forward in recent years to understand some of these results. We also present novel theoretical results explaining the periodic aging experiment.
Electronic Transport in Graphene Heterostructures
Authors: Young Andrea F. , Kim Philip
Published: February 2011

The elementary excitations of monolayer graphene, which behave as massless Dirac particles, make it a fascinating venue in which to study relativistic quantum phenomena. One notable example is Klein tunneling, a phenomena in which electrons convert to holes to tunnel through a potential barrier. However, the omnipresence of charged impurities in substrate-supported samples keep the overall charge distribution nonuniform, obscuring much of this “Dirac” point physics in large samples. Using local gates, one can create tunable heterojunctions in graphene, isolating the contribution of small regions of the samples to transport. In this review, we give an overview of quantum transport theory and experiment on locally gated graphene heterostructures, with an emphasis on bipolar junctions.
Life is Physics: Evolution as a Collective Phenomenon Far From Equilibrium
Authors: Goldenfeld Nigel , Woese Carl
Published: February 2011

Evolution is the fundamental physical process that gives rise to biological phenomena. Yet it is widely treated as a subset of population genetics, and thus its scope is artificially limited. As a result, the key issues of how rapidly evolution occurs and its coupling to ecology have not been satisfactorily addressed and formulated. The lack of widespread appreciation for, and understanding of, the evolutionary process has arguably retarded the development of biology as a science, with disastrous consequences for its applications to medicine, ecology, and the global environment. This review focuses on evolution as a problem in nonequilibrium statistical mechanics, where the key dynamical modes are collective, as evidenced by the plethora of mobile genetic elements whose role in shaping evolution has been revealed by modern genomic surveys. We discuss how condensed matter physics concepts might provide a useful perspective in evolutionary biology, the conceptual failings of the modern evolutionary synthesis, the open-ended growth of complexity, and the quintessentially self-referential nature of evolutionary dynamics.
Materials and Novel Superconductivity in Iron Pnictide Superconductors
Authors: Wen Hai-Hu , Li Shiliang
Published: February 2011

Since the first report on superconductivity at 26 K in F-doped LaOFeAs at the end of February 2008, the iron pnictide superconductor family has been quickly expanded to six different structures, and the superconducting transition temperature has been rapidly raised to approximately 57 K. Meanwhile, the pairing mechanism has been clarified as nonconventional, and the antiferromagnetic (AF) spin fluctuations (SFs) seem to play important roles in making these pairs. This article covers a brief overview of the materials and novel superconductivity in this fascinating field, including issues concerning the materials and structures, phase diagram, pairing symmetry, and spin excitations. We give perspectives on these topics and raise questions instead of simply summarizing the theoretical and experimental achievements about the superconducting mechanism.
Mott Physics in Organic Conductors with Triangular Lattices
Authors: Kanoda Kazushi , Kato Reizo
Published: February 2011

Electron correlation and spin frustration are among the central issues in condensed matter physics, and their interplay is expected to bring about exotic phases with both charge and spin fluctuations. Molecular materials are playgrounds suitable for this study. Fundamentals in physics of Mott transition and spin frustration on triangular lattices are seen in the organic materials ET and Pd(dmit)2 compounds. We review the experimental studies on the criticality of Mott transition with a continuously controllable pressure technique and on the ground state of the quasi-triangular-lattice Mott insulator. Mott criticality is well characterized in both charge and spin channels with unconventional critical exponents of possibly quantum nature. The ground state of the triangular-lattice Mott insulator is changed from antiferromagnet to spin liquid as the triangular lattice becomes more isotropic. The various experiments probing the nature of spin liquid are described in the light of proposed mechanisms.
The Ubiquity of Superconductivity
Authors: Leggett Anthony J.
Published: February 2011

After a brief review of the phenomenology of superconductivity and of its generic explanation in terms of the concept of off-diagonal long-range order, I first survey the original Bardeen-Cooper-Schrieffer (BCS) weak-coupling model and some extensions of it. I then turn to systems such as the heavy fermions and the cuprates where the superconductivity is generally believed to be due to an all-electronic mechanism, and ask how much information we get about this mechanism from quite general energetic and other considerations, without committing ourselves to any particular microscopic model.
Gastric bypass surgery is associated with near-normal insulin suppression of lipolysis in nondiabetic individuals
Authors: Curry Timothy B. , Roberts Shelly K. , Basu Rita , Basu Ananda , Schroeder Darrell , Joyner Michael J. , Miles John M.
Published: February 2011

We hypothesized that individuals who have undergone gastric bypass have greater insulin sensitivity that obese subjects but less compared with lean. We measured free fatty acid (FFA) and glucose kinetics during a two-step, hyperinsulinemic euglycemic clamp in nondiabetic subjects who were 38 ± 5 mo post-gastric bypass surgery (GB; n = 15), in lean subjects (L; n = 15), and in obese subjects (O; n = 16). Fasting FFAa were not significantly different between the three study groups but during both doses of insulin were significantly higher in O than in either GB or L. The effective insulin concentration resulting in half-maximal suppression of FFA was similar in L and GB and significantly less in both groups compared with O. Glucose infusion rates during low-dose insulin were not significantly different in GB compared with either L or O. During high-dose insulin, glucose infusion rates were significantly greater in GB than in O but less than in L. Endogenous glucose production in GB was significantly lower than O only during low dose of insulin. We conclude that gastric bypass is associated with improvements in adipose tissue insulin sensitivity to levels similar to lean, healthy persons and also with improvements in the response of glucose metabolism to insulin. These changes may be due to preferential reduction in visceral fat and decreased FFA availability. However, some differences in insulin sensitivity in GB remain compared with L. Residual insulin resistance may be related to excess total body fat or abnormal lipolysis and requires further study.
Analytical Solution for Different Profiles of Fin with Temperature‐Dependent Thermal Conductivity
Authors: Moradi A. , Ahmadikia H.
Published: February 2011

Three different profiles of the straight fin that has a temperature‐dependent thermal conductivity are investigated by differential transformation method (DTM) and compared with numerical solution. Fin profiles are rectangular, convex, and exponential. For validation of the DTM, the heat equation is solved numerically by the fourth‐order Runge‐Kutta method. The temperature distribution, fin efficiency, and fin heat transfer rate are presented for three fin profiles and a range of values of heat transfer parameters. DTM results indicate that series converge rapidly with high accuracy. The efficiency and base temperature of the exponential profile are higher than the rectangular and the convex profiles. The results indicate that the numerical data and analytical method are in agreement with each other.
Increased Placental Glucose Transport Rates in Pregnant Mice Carrying Fetuses with Targeted Disruption of Their Placental-SpecificIgf2Transcripts Are Not Associated with Raised Circulating Glucose Concentrations
Authors: Petry Clive J. , Evans Mark L. , Wingate Dianne L. , Ong Ken K. , Reik Wolf , Constância Miguel , Dunger David B.
Published: February 2011

At the beginning of the third week of pregnancy, mouse fetuses with targeted disruption of their paternally-transmitted insulin-like growth factor 2 gene placental-specific transcripts have growth-restricted placentas but normal body weights due to upregulated placental nutrient transport. We assessed whether increased placental glucose transport rates were associated with raised maternal glucose concentrations by performing intraperitoneal glucose tolerance tests (ipGTT) in pregnant mice carrying knockout pups and comparing them with mice carrying genotype-matched phenotypically wild type pups. Mean ± SD body weights of affected pups were 95 ± 8% of control values at e16 and 73 ± 7% at e18. There were no differences in areas under the maternal ipGTT curves at either e16 (mean ± SD being 99.0 ± 9.1% of control values;P=.9) or e18 (91.4 ± 13.4%;P=.3), suggesting that effects on transplacental glucose transport in these mice are not mediated through changes in maternal glucose concentrations.
Leptin, Adiponectin, and Obesity among Caucasian and Asian Women
Authors: Conroy Shannon M. , Chai Weiwen , Lim Unhee , Franke Adrian A. , Cooney Robert V. , Maskarinec Gertraud
Published: February 2011

Ethnic differences in adipose tissue distribution may contribute to different chronic disease risks across ethnic groups, and adipokines may mediate the risk. In a cross-sectional study, we examined ethnic differences in adipokines and inflammatory markers as related to body mass index (BMI) among 183 premenopausal women with Caucasian and Asian ancestry. General linear models were used to estimate adjusted mean levels of leptin, adiponectin, interleukin-6, and C-reactive protein (CRP). Asian women had significantly lower serum levels of leptin, adiponectin, and CRP than Caucasian participants (P≤.01) across all levels of BMI. Among overweight and obese women, Asians showed a stronger association of CRP with leptin (β=1.34versusβ=0.64) and with adiponectin (β=−0.95versusβ=−0.75) than Caucasians. Compared to Caucasians of similar BMI, Asians may experience a higher chronic disease risk due to lower levels of adiponectin despite their lower levels of leptin.
Nanostructural Materials for Energy Storage Systems
Authors: Buczek Bronislaw
Published: February 2011

The aim of this study was to assess of carbonaceous monoliths used for adsorption cooling systems. The carbonaceous monoliths prepared from coal precursors are obtained. The porous structure of monoliths was evaluated on the basis of nitrogen adsorption-desorption data. The investigated monoliths have significantly developed microporous structure. The large specific area of carbonaceous monoliths (about 2000 m2/g) and volume of micropores are observed. Methanol adsorption isotherms and heat of wetting using methanol was determined. Results show that monoliths materials are high adsorption capacity of methanol and heat of wetting, which can improve of heat exchange and efficiency in processes of refrigeration and air conditioning.
Some Properties of Subclasses of Multivalent Functions
Authors: Kamali Muhammet , Sağsöz Fatma
Published: February 2011

The authors introduce two new subclasses denoted by ℑ∗(Ω, λ, p, α) and of the class A(p, n) of p‐valent analytic functions. They obtain coefficient inequality for the class ℑ∗(Ω, λ, p, α). They investigate various properties of classes ℑ∗(Ω, λ, p, α) and . Furthermore, they derive partial sums associated with the class .
Usefulness of Ultrasound Imaging in Detecting Psoriatic Arthritis of Fingers and Toes in Patients with Psoriasis
Authors: De simone Clara , Caldarola Giacomo , D'Agostino Magda , Carbone Angelo , Guerriero Cristina , Bonomo Lorenzo , Amerio Pierluigi , Magarelli Nicola
Published: February 2011

Background. Given that clinical evaluation may underestimate the joint damage and that early treatment can slow down psoriatic arthritis (PsA) progression, screening psoriasis patients with imaging tools that can depict early PsA changes would entail clear benefits.Objective. To compare the ability of X-ray and ultrasound (US) examination in detecting morphological abnormalities consistent with early PsA in patients with psoriasis, using rheumatological evaluation as the gold standard for diagnosis.Methods. Patients with chronic plaque psoriasis and no previous PsA diagnosis attending our outpatient dermatology clinic and reporting finger/toe joint and/or tendon pain underwent X-ray and US evaluation; they were subsequently referred to a rheumatologist for clinical examination and review of imaging findings.Results. Abnormal US and/or X-ray findings involving at least one finger and/or toe (joints and/or tendons) were seen in 36/52 patients: 11 had one or more X-ray abnormalities, including erosion, joint space narrowing, new bone formation, periarticular soft tissue swelling, and periarticular osteoporosis; 36 had suspicious changes on US.Conclusion. US proved valuable in detecting joint and/or tendon abnormalities in the fingers and toes of patients with suspicious changes. The dermatologist should consider US to obtain an accurate assessment of suspicious findings.