bluuebunny/crossref_metadata_2025 huggingface dataset:
Liar's domination
Authors: Slater Peter J.
Published: February 2009

Assume that each vertex of a graph G is the possible location for an “intruder” such as a thief, or a saboteur, a fire in a facility or some possible processor fault in a computer network. A device at a vertex v is assumed to be able to detect the intruder at any vertex in its closed neighborhood N[v] and to identify at which vertex in N[v] the intruder is located. One must then have a dominating set S ⊆ V(G), a set with ∪v∈SN[v] = V(G), to be able to identify any intruder's location. If any one device can fail to detect the intruder, then one needs a double‐dominating set. This article introduces the study of liar's dominating sets, sets that can identify an intruder's location even when any one device in the neighborhood of the intruder vertex can lie, that is, any one device in the neighborhood of the intruder vertex can misidentify any vertex in its closed neighborhood as the intruder location. Liar's dominating sets lie between double‐dominating sets and triple‐dominating sets because every triple‐dominating set is a liar's dominating set, and every liar's dominating set must double dominate. © 2009 Wiley Periodicals, Inc. NETWORKS, 2009
A generalization of an edge‐connectivity theorem of Chartrand
Authors: Boesch Frank , Gross Daniel , Saccoman John T. , Kazmierczak L. William , Suffel Charles , Suhartomo Antonius
Published: February 2009

In 1966, Chartrand proved that if the minimum degree of a graph is at least the floor of half the number of nodes, then its edge‐connectivity equals its minimum degree. A more discriminating notion of edge‐connectivity is introduced, called the k‐component order edge‐connectivity, which is the minimum number of edges required to be removed so that the order of each component of the resulting subgraph is less than k. Results are established that guarantee that this parameter is at least as large as the minimum degree, provided the minimum degree is sufficiently large. This generalizes Chartrand's result. It is also determined when these results are best possible. © 2009 Wiley Periodicals, Inc. NETWORKS, 2009
Rheological properties of UHMWPE/iPP blends
Authors: Lee Eon Mi , Oh Young Se , Ha Hyun Soo , Kim Byung Kyu
Published: February 2009

The effects of isotactic polypropylene (PP) on the rheological properties of ultra high molecular weight polyethylene (UHMWPE) have been measured in a broad range of composition (0, 5, 15, 30 wt% PP) at various temperatures (110, 130, and 150°C) and a specific gel concentration of 6 wt%. The result showed that the viscosity of the UHMWPE significantly decreased with the addition and increasing amount of PP. Regardless of temperature, the viscosity function followed the power‐law behavior. Copyright © 2009 John Wiley & Sons, Ltd.
Preparation of polyaniline‐coated mesoporous carbon and its enhanced electrochemical properties
Authors: Xing Wei , Yuan Xun , Zhuo Shu‐Ping , Huang Cong‐Cong
Published: February 2009

Polyaniline/MC (mesoporous carbon) composite was synthesized by in situ chemical polymerization method and was used as a new electrode material for supercapacitor. The composite was characterized by N2 adsorption and scanning electron microscope. The electrochemical capacitance performance of the composite was investigated by cyclic voltammetry (CV) and galvanostatic charge–discharge tests with a three‐electrode system in a 10 wt% H2SO4 solution. The polyaniline/MC composite electrode shows much higher specific capacitance than pure MC electrode, which is attributed to the incorporation of polyaniline onto the pore surface of MC. Copyright © 2009 John Wiley & Sons, Ltd.
Surface characterization of air plasma treated poly vinylidene fluoride and poly methyl methacrylate films
Authors: Pawde S.M. , Deshmukh Kalim
Published: February 2009

In this investigation, the surface modification of poly vinylidene fluoride (PVDF) and poly methyl methacrylate (PMMA) film induced by air plasma has been investigated using contact angle measurement, electron spectroscopy for chemical analysis (ESCA), and ATR‐FTIR spectroscopy. Plasma treatment affects the polymer surfaces to an extent of several hundreds to several thousand angstroms deep, and the bulk properties of the polymer substrate are never modified because of its low penetration range. Plasma surface treatment also offers the advantage of greater chemical flexibility. The plasma exposure leads to weight loss and changes in the chemical composition of the polymer film surfaces. The contact angle of water shows decrease in surface wettability of PVDF and PMMA as the treatment time increases. The improvement in adhesion was studied by measuring T‐peel strength. In addition, printability of plasma treated PVDF and PMMA was studied by cross test method. It was found that printability increases considerably for plasma treatment of short duration. Surface energy and surface roughness can be directly correlated to the improvement in the aforementioned surface related properties. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Magnetoimpedance (MI) in amorphous wires: new materials and applications
Authors: Panina Larissa V.
Published: February 2009

The discovery of the magnetoimpedance (MI) effect in 1994 had a strong impact on the development of magnetic sensors. Along with traditional areas of sensing applications (data storage, bio‐medical electronics, robotics and security), the MI elements have a high potential for applications in smart sensory systems (self‐sensing composites) operating at microwave frequencies owing to still very large MI ratios of 50–100% in Co‐rich amorphous wires at GHz frequencies. Here we introduce two types of MI wire composites: 2D‐arrays and mixtures of wire pieces. In such materials the effective permittivity has strong dispersion in a frequency band determined by a plasma frequency or a dipole resonance, respectively. If MI wires are used as constituent elements, this dispersion may be very sensitive to the magnetic properties of wires since the wire impedance determines the relaxation parameter of the effective permittivity. For example, increasing the wire impedance by establishing the magnetisation along the axis with an external magnetic field broadens the resonance band, decreases the reflection amplitude and may open a bandpass. Depending on the magnetic anisotropy in wires, tuning can be realized with both magnetic field and stress. It is foreseen that MI‐wire composite materials could be suitable for large scale applications, in particular, for free space filters in secure wireless systems and for microwave nondestructive testing and control in civil engineering. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of substrate dislocation density and quantum well width on the quantum efficiency of violet‐emitting GaInN/GaN light‐emitting diodes
Authors: Passow Thorsten , Maier Markus , Kunzer Michael , Leancu Crenguta‐Columbina , Liu Shangjing , Wiegert Joachim , Schmidt Ralf , Köhler Klaus , Wagner Joachim
Published: February 2009

Three series of GaInN/GaN light‐emitting diodes (LEDs) emitting at 400 nm with well widths varying between 3 and 18 nm were grown on sapphire, ultra‐low dislocation density GaN templates, and free‐standing GaN substrates. Photoluminescence and pulsed electroluminescence were systematically investigated. Photoluminescence spectroscopy showed a noteworthy increase in radiative efficiency for GaInN/GaN double‐heterostructures or wide wells on low dislocation density substrates. The electroluminescence properties significantly differ for wide well LEDs on sapphire and on low defect density substrates but are comparable for LEDs containing thin single quantum wells. Increasing well width leads to decreasing quantum efficiency at all currents for LEDs on sapphire. The highest overall efficiency is obtained for LEDs with 11 nm and 18 nm thick DHs on GaN templates and free‐standing GaN substrates, respectively, at current densities above 200 A/cm2. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Direct observation of crosssectional potential distribution in GaN‐based MIS structures by Kelvin‐probe force microscopy
Authors: Kaneko Masamitsu , Fujishima Tatsuya , Chikamatsu Kentaro , Yamaguchi Atsushi , Kikawa Junjiroh , Otake Hirotaka , Nanishi Yasushi
Published: February 2009

Cross‐sectional potential distribution in GaN‐based trench gate metal‐insulator‐semiconductor field‐effect transistors (MISFET) at off‐ and operating‐state has been investigated by using Kelvin‐probe force microscopy to clarify the actual operating situation of trench gate MISFET. The potential distribution reflecting the wafer structure, n/p/n–/n+, is observed as shown in the right figure. At the off‐state (the gate voltage is fixed to 0 V), it is found that the electric field at the internal p/n– interface become strong, on the contrary to that at top n/p interface is almost unchanged by the stepwise increase of the drain bias from 0 to 15 V. From the analysis of results obtained at operating state, we can confirm the situation how the channel forms by increasing the gate voltage. This information is useful for designing devices and improving their characteristics (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoreflectance spectroscopy of the band bending and the energy gap for Mg‐doped InN layers
Authors: Kudrawiec R. , Suski T. , Misiewicz J. , Muto D. , Nanishi Y.
Published: February 2009

Photoreflectance (PR) spectroscopy has been applied to investigate the band bending (built‐in electric field) and the energy gap for Mg‐doped InN layers with various Mg concentrations (4.0‐7.3 × 1020 cm–3). A broad PR resonance followed by the Franz‐Keldysh oscillation, which is typical of the band‐to‐band absorption in the sample region with strong band bending, has been observed at the energy of ∼0.66‐0.7 eV. The region of strong band bending in InN:Mg layers results from the Fermi level pinning at the energy range i) above the conduction band at the sample surface and ii) close to the valence band inside InN:Mg layer due to Mg‐doping. The built‐in electric field in this region has been estimated from the Franz‐Keldysh oscillation to be ∼0.6‐0.8 MV/cm. In addition, it has been observed that the energy gap of InN:Mg is reduced from about 0.70 eV to 0.66 eV with the increase in Mg concentration from 4 to 7.3 × 1020 cm–3. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Correlation of surface morphology and photoluminescence fluctuation in green light emitting InGaN/GaN quantum wells
Authors: Danhof Julia , Vierheilig Clemens , Schwarz Ulrich T. , Meyer Tobias , Peter Matthias , Hahn Berthold , Maier Markus , Wagner Joachim
Published: February 2009

For InGaN/GaN multiple quantum well structures a correlation of surface morphology and photoluminescence fluctuations has been established by comparing atomic force microscopy images with PL measurements of the same area. The two analyzed samples were grown simultaneously, but on different substrates and therefore with different dislocation densities. Their PL peak wave lengths lie in between 510 nm and 520 nm. Meandering structures observed for both samples by micro– photoluminescence (μPL) are in the case of the sample on GaN substrate not created by threading dislocations. Threading dislocations may influence the development of meandering structures but do not cause them (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polar and nonpolar HVPE GaN substrates: impact of doping on the structural, electrical and optical characteristics
Authors: Paskova T. , Preble E. A. , Hanser A. D. , Evans K. R. , Kröger R. , Paskov P. P. , Cheng A. J. , Park M. , Grenko J. A. , Johnson M. A. L.
Published: February 2009

Polar and nonpolar bulk GaN substrates with low defect density and high structural and optical quality are demonstrated. The effect of doping by silicon, oxygen and iron within moderate doping levels on the properties of the polar GaN substrates was found uncompromised, as confirmed by high resolution X‐ray diffraction and low temperature photoluminescence spectroscopy. In contrast, the lattice parameters were affected significantly, which has to be considered in the subsequent homoepitaxial device growth. The boule growth and respectively the nonpolar substrate homogeneity were found to be hampered by the doping, due to surface microcracking and higher impurity incorporation, while n‐type undoped nonpolar substrates were demonstrated of superior quality. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vertically‐stacked color‐tunable LEDs
Authors: Hui K. N. , Lai P. T. , Choi H. W.
Published: February 2009

Light‐emitting diodes with vertical stacking geometry were fabricated and characterized. Color‐tunable emission and white‐light emission has been demonstrated in Stacked‐LED (SLED). Emissions of different colors, ranging from green‐blue, to pink‐purple, to yellow‐orange and white light emission have be achieved by adjusting the relative intensity of two or three individual emission bands, which in turn are controlled by adjusting voltage supply. Compared to conventional lateral side‐by‐side geometry, the shift of white color chromaticity with respect to viewing angles is less in the case of SLED device. The farthest shift of white CIE coordinate point away from the pure white CIE coordinate is (0.29, 0.29) in SLED compared to (0.37, 0.35) in the commerical available lateral packaged structure. This vertically‐stacked LED is poised to open new frontiers in high performance color‐tunable LEDs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micro‐structural anisotropy of a‐plane GaN analyzed by high resolution X‐ray diffraction
Authors: Wieneke Matthias , Bläsing Jürgen , Dadgar Armin , Veit Peter , Metzner Sebastian , Bertram Frank , Christen Jürgen , Krost Alois
Published: February 2009

Nonpolar a‐plane GaN films were grown on r‐plane sapphire by metal‐organic vapour phase epitaxy. Conventionally grown samples exhibit high dislocation densities, as basal stacking faults and partial dislocations. To reduce the defect density in‐situ SiN nanomasks were used. In high resolution X‐ray diffraction ω‐scans the full width of half maximum of the symmetric GaN (11‐20) reflection is azimuthally dependent on the in‐plane beam orientation. By measuring several higher order reflections the causes of broadening, the rotational disorder of the crystallites, and the coherent scattering length parallel to the in‐plane beam orientation are analyzed by a graphical separation known as Williamson‐Hall‐Plot. In addition the micro‐structural properties of the grown samples were investigated by transmission electron microscopy and cathodoluminescence. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Strain engineering of AlGaN‐GaN HFETs grown on 3 inch 4H‐SiC
Authors: Brunner Frank , Reentilä Outi , Würfl Joachim , Weyers Markus
Published: February 2009

In this work strain evolution during MOVPE of AlGaN/GaN HFET structures on 3 inch SiC substrates is investigated in‐situ and related to properties of the initial AlN wetting layer. It is shown that the density of pits on the AlN surface depending on growth conditions influences GaN nucleation and consequential grain coalescence and stress incorporation. Optimization of the strain and material quality of the GaN layer is demonstrated without degrading the semi‐insulating properties of the HFET buffer. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In silico Prediction of Androgenic and Nonandrogenic Compounds Using Random Forest
Authors: Li Yan , Wang Yonghua , Ding Jun , Wang Yuan , Chang Yaqing , Zhang Shuwei
Published: February 2009

The purpose of the present study was to develop in silico models allowing for a reliable prediction of androgenic and nonandrogenic compounds based on a large diverse dataset of 205 compounds. As a new classification method, the Random Forest (RF) was applied, its performance to classify these compounds in terms of their Quantitative Structure–Activity Relationships (QSAR) was evaluated and also compared with the widely used Partial Least Squares (PLS) analysis for the dataset. The predictive power of these methods was verified with five‐fold cross‐validation and an independent test set. For the RF model, the prediction accuracies of the androgenic and nonandrogenic compounds are 81.0 and 77.0% for cross‐validation, respectively, averaging 87.3% of correctly classified compounds in the external tests. The PLS is slightly weak, showing an average prediction accuracy of 75 and 74.7% for the cross‐validation and external validation, respectively. Our analysis demonstrates that RF is a powerful tool capable of building models for the data and should be valuable for virtual screening of androgen receptor‐binding ligands.
Influence of Changes in 2‐D Chemical Structure Drawings and Image Formats on the Prediction of Biological Properties Using MIA‐QSAR
Authors: Goodarzi Mohammad , Freitas Matheus P. , Ferreira Eric B.
Published: February 2009

Multivariate Image Analysis Applied to Quantitative Structure–Activity Relationships (MIA‐QSAR) has been recently implemented as a method to model and predict biological activities of drug‐like compounds. This method is based on the treatment of 2‐D chemical structures, which can be built using specific packages for chemical drawing. These chemical structures correlate with the corresponding bioactivities through descriptors, which are pixels (binaries) of the 2‐D images; the variable moiety of chemical structures (substituent groups) explains the variance in the bioactivities column vector of a series of compounds. Thus, the way in which chemical structures are drawn (font type and size, representation of chemical groups, format in which images are saved) should influence the results of prediction. This work reports the statistics of prediction for a case study, a series of anti‐HIV compounds, and reveals that the results of prediction is independent of the way in which molecules are drawn.
ChemGPS‐NP Mapping of Chemical Compounds for Prediction of Anticancer Mode of Action
Authors: Rosén Josefin , Rickardson Linda , Backlund Anders , Gullbo Joachim , Bohlin Lars , Larsson Rolf , Gottfries Johan
Published: February 2009

A combined graph describing the growth inhibition values from a number of human cancer cell lines represents an activity profile for a compound. The fact that compounds with similar activity profiles often show similar Mode of Action (MOA) has frequently been used in prediction of MOA. Obtaining the profiles is demanding with respect to both time and resources. Therefore, as a work and time efficient alternative, we explore the central premise of medicinal chemistry that structurally similar molecules often have similar biological activity. In this study we investigate correlations between chemical structure and MOA, and subsequently use this as a complementing basis for prediction. The correlations between MOA and activity profile on one hand and between MOA and chemical structure on the other were analyzed for anticancer agents, classified with regard to MOA, using Principal Component Analysis (PCA), chemographic mapping with ChemGPS‐NP, and Orthogonal Partial Least Squares Discriminant Analysis (OPLS‐DA). The compounds clustered according to MOA both based on chemical structures and activity profiles. The subsequent validation with external test sets showed that initial PCA scores prediction or chemographic mapping followed by OPLS‐DA could be used for the prediction of MOA as well as identification of novel MOAs in a highly accurate way. An efficient and straight forward procedure for the prediction of MOA of anticancer agents is suggested. With today's resistance problems in cancer therapy, there is a need for new anticancer agents and mechanisms. We believe that the fast initial virtual guidance this procedure implies, especially the novel step using ChemGPS‐NP, could be of general use in early stages of cancer research.
CO2 isotope analyses using large air samples collected on intercontinental flights by the CARIBIC Boeing 767
Authors: Assonov S. S. , Brenninkmeijer C. A. M. , Koeppel C. , Röckmann T.
Published: February 2009

Analytical details for 13C and 18O isotope analyses of atmospheric CO2 in large air samples are given. The large air samples of nominally 300 L were collected during the passenger aircraft‐based atmospheric chemistry research project CARIBIC and analyzed for a large number of trace gases and isotopic composition. In the laboratory, an ultra‐pure and high efficiency extraction system and high‐quality isotope ratio mass spectrometry were used. Because direct comparison with other laboratories was practically impossible, the extraction and measurement procedures were tested in considerable detail. Extracted CO2 was measured twice vs. two different working reference CO2 gases of different isotopic composition. The two data sets agree well and their distributions can be used to evaluate analytical errors due to isotope measurement, ion corrections, internal calibration consistency, etc. The calibration itself is based on NBS‐19 and also verified using isotope analyses on pure CO2 gases (NIST Reference Materials (RMs) and NARCIS CO2 gases). The major problem encountered could be attributed to CO2‐water exchange in the air sampling cylinders. This exchange decreased over the years. To exclude artefacts due to such isotopic exchange, the data were filtered to reject negative δ18O(CO2) values. Examples of the results are given. Copyright © 2009 John Wiley & Sons, Ltd.
Sequence‐Specific HCV RNA Quantification Using the Size‐Dependent Nonlinear Optical Properties of Gold Nanoparticles
Authors: Griffin Jelani , Singh Anant Kumar , Senapati Dulal , Lee Eumin , Gaylor Kevin , Jones‐Boone Jeanette , Ray Paresh Chandra
Published: February 2009

The hepatitis C virus (HCV) is a single‐stranded (ss) RNA virus that is responsible for chronic liver diseases, such as cirrhosis, end‐stage liver disease, and hepatocellular carcinoma. Driven by the need to detect the presence of the HCV viral sequence, herein it is demonstrated for the first time that the nonlinear optical (NLO) properties of gold nanoparticles can be used for screening and quantifying HCV RNA without any modification, with excellent detection limit (80 pM) and selectivity (single base‐pair mismatch). The hyper‐Rayleigh scattering (HRS) intensity increases 25 times when label‐free, 145‐mer, HCV ss‐RNA is hybridized with 400 pM target RNA. The mechanism of HRS intensity change is discussed with experimental evidence for a higher multipolar contribution to the NLO response of gold nanoparticles.
Characterization of Dendritic Cells and Macrophages Generated by Directed Differentiation from Mouse Induced Pluripotent Stem Cells
Authors: Senju Satoru , Haruta Miwa , Matsunaga Yusuke , Fukushima Satoshi , Ikeda Tokunori , Takahashi Kazutoshi , Okita Keisuke , Yamanaka Shinya , Nishimura Yasuharu
Published: February 2009

Methods have been established to generate dendritic cells (DCs) from mouse and human embryonic stem (ES) cells. We designated them as ES-DCs and mouse models have demonstrated the induction of anti-cancer immunity and prevention of autoimmune disease by in vivo administration of genetically engineered ES-DCs. For the future clinical application of ES-DCs, the histoincompatibility between patients to be treated and available human ES cells and the ethical concerns associated with human ES cells may be serious obstacles. However, recently developed induced pluripotent stem (iPS) cell technology is expected to resolve these issues. This report describes the generation and characterization of DCs derived from mouse iPS cells. The iPS cell-derived DCs (iPS-DCs) possessed the characteristics of DCs including the capacity of T-cell-stimulation, antigen-processing and presentation and cytokine production. DNA microarray analyses revealed the upregulation of genes related to antigen-presenting functions during differentiation into iPS-DCs and similarity in gene expression profile in iPS-DCs and bone marrow cell-derived DCs. Genetically modified iPS-DCs expressing antigenic protein primed T-cells specific to the antigen in vivo and elicited efficient antigen-specific anti-tumor immunity. In addition, macrophages were generated from iPS cells (iPS-MP). iPS-MP were comparable with bone marrow cell-derived macrophages in the cell surface phenotype, functions, and gene expression profiles.

Disclosure of potential conflicts of interest is found at the end of this article.
Harmonizing high performance computing (HPC) with large‐scale complex systems in computational science and engineering
Authors: Chittister Clyde , Haimes Yacov Y.
Published: February 2009

This paper addresses the challenges facing the three different groups within the professional community that support the development of large‐scale scientific and engineering (CSE) software applications. Scientific and engineering systems are but one example of large‐scale complex (LSC) systems. The authors recognize that many of the observations made in this paper also apply to the larger domain. The focus of this paper is restricted to CSE because it is the source of the experiences from which the observations are derived. The first of the groups encompasses the application developers of large‐scale scientific and engineering software systems, especially those requiring high‐performance computing (HPC). The second group covers the HPC software development and run‐time environments. The third consists of the integrators of the first two groups, with a focus on the systems engineers whose task is to bridge the technical and cultural gap between the other two. These challenges reside in several areas, the most important being the educational and cultural backgrounds that are reflected in the knowledge, expertise, and experience of the principals involved. In particular, the cultural gaps and thus the communications and ultimate systems integration challenges are the byproducts of the academic educational system that graduates most software engineers without formal courses in systems engineering, process control, and systems integration. All three groups of challenges are explored individually and in conjunction with each other. Thus, a major problem addressed here is centered in software, because the developers of LSC systems in CSE perceive hardware through the HPC software development environment. Given the unique attributes and characteristics of LSC‐HPC systems, to meet the challenge of the risk modeling, assessment, and management associated with them—at least partially—this paper discusses two complementary approaches: decomposition and hierarchical modeling, which, when applied in conjunction with conventional aggregate modeling methods, offers several promising advantages, especially when dealing with LSC‐HPC systems, and Phantom System Models, used as a real‐time and virtual modeling laboratory for systems integration and risk assessment and management. © 2009 Wiley Periodicals, Inc. Syst Eng
Anxiety disorders in children with Williams syndrome, their mothers, and their siblings: Implications for the etiology of anxiety disorders
Authors: Leyfer Ovsanna , Woodruff-Borden Janet , Mervis Carolyn B.
Published: February 2009

This study examines the prevalence of anxiety disorders in children with Williams syndrome (WS), their sibling closest in age, and their mothers as well as the predictors of anxiety in these groups. The prevalence of anxiety disorders was assessed and compared to that in the general population. Children with WS had a significantly higher prevalence of specific phobia, generalized anxiety disorder (GAD), and separation anxiety in comparison to children in the general population. While mothers had a higher prevalence of GAD than population controls, the excess was accounted for by mothers who had onset after the birth of their WS child. The siblings had rates similar to the general population. This pattern of findings suggests the presence of a gene in the WS region whose deletion predisposes to anxiety disorders. It is also worthwhile to investigate relations between genes deleted in WS and genes previously implicated in anxiety disorders.
The symplectic structure of curves in three dimensional spaces of constant curvature and the equations of mathematical physics
Authors: Jurdjevic V.
Published: February 2009

The paper defines a symplectic form on an infinite dimensional Fréchet manifold of framed curves over the three dimensional space forms. The curves over which the symplectic form is defined are called horizontal-Darboux curves. It is then shown that the projection on the Lie algebra of the Hamiltonian vector field associated with the functional

f = \frac{1}{2}\int _{0}^{L}\kappa ^{2}(s)\:ds

satisfies Heisenberg's magnetic equation (HME),

\frac{\partial \Lambda }{\partial t}(s,t) = \frac{1}{i}[\Lambda (s),\frac{\partial ^{2}\Lambda }{\partial s^{2}}(s,t)]

in the space of Hermitian matrices for the hyperbolic and the Euclidean case, and

\frac{\partial \Lambda }{\partial t}(s,t) = [\Lambda (s),\frac{\partial ^{2}\Lambda }{\partial s^{2}}(s,t)]

in the space of skew-Hermitian matrices for the spherical case. It is then shown that the horizontal-Darboux curves are parametrized by curves in

SU_{2}

, which along the solutions of (HME) satisfy Schroedinger's non-linear equation (NSL)

−i\frac{\partial \psi }{\partial t}(t,s) = \frac{\partial ^{2}\psi }{\partial s^{2}}(t,s) + \frac{1}{2}\left(|\psi (t,s)|^{2} + c\right)\psi (t,s)

It is also shown that the critical points of

\frac{1}{2}\int _{0}^{L}\kappa ^{2}(s)\:ds

, known as the elastic curves, correspond to the soliton solutions of (NSL). Finally the paper shows that the modifed Korteweg–de Vries equation or the curve shortening equation are Hamiltonian equations generated by

f_{1} = \int _{0}^{L}\kappa ^{2}(s)\tau (s)\:ds

and

f_{2} = \int _{0}^{L}\tau (s)\:ds

and that

f_{0} = \frac{1}{2}\int _{0}^{L}\kappa ^{2}(s)\:ds

,

f_{1}

and

f_{2}

are all in involution with each other.
On the uniqueness of the second bound state solution of a semilinear equation
Authors: Yarur Cecilia S. , Cortázar Carmen , García-Huidobro Marta
Published: February 2009

We establish the uniqueness of the second radial bound state solution of

\mathrm{\Delta }u + f(u) = 0,\:x \in \mathbb{R}^{n}.

We assume that the nonlinearity

f \in C(−\infty ,\infty )

is an odd function satisfying some convexity and growth conditions of superlinear type, and either has one zero at

b > 0

, is nonpositive and not identically 0 in

(0,b)

, and is differentiable and positive

[b,\infty)

, or is positive and differentiable in

[0,\infty)

.
Approximate controllability for a system of Schrödinger equations modeling a single trapped ion
Authors: Ervedoza Sylvain , Puel Jean-Pierre
Published: February 2009

In this article, we analyze the approximate controllability properties for a system of Schrödinger equations modeling a single trapped ion. The control we use has a special form, which takes its origin from practical limitations. Our approach is based on the controllability of an approximate finite dimensional system for which one can design explicitly exact controls. We then justify the approximations which link up the complete and approximate systems. This yields approximate controllability results in the natural space

(L^{2}(\mathbb{R})^{2})

and also in stronger spaces corresponding to the domains of powers of the harmonic operator.

Dans cet article, nous étudions les propriétés de contrôlabilité approchée pour un système d'équations de Schrödinger modélisant un ion piégé. Nous nous limitons à un contrôle d'une forme particulière, correspondant à des restrictions pratiques. Notre approche est fondée sur l'analyse de la contrôlablité d'un système approché de dimension finie, pour lequel il est possible de construire explicitement des contrôles exacts. Nous justifions alors précisément les approximations qui relient le système complet au système approché. Nous en déduisons des résultats de contrôlabilité approchée dans l'espace naturel

(L^{2}(\mathbb{R})^{2})

mais aussi dans des espaces plus forts correspondants aux domaines des puissances de l'opérateur harmonique.
Modern Chemotherapy Strategies for Management of ‘Hormone Resistant Prostate Cancer’ (HRPC)—When Should the Urologist Refer?
Authors: Persad Raj A. , Bahl Amit
Published: February 2009

Before death occurs from advanced prostate cancer, all patients pass through a ‘hormone resistant’ phase of the disease (HRPC). A large proportion of patients with advanced prostate cancer on hormonal therapy are managed in the Urology Outpatient Department, albeit with multidisciplinary input into their care. Chemotherapy for HRPC has now been shown to increase survival and quality of life and many novel agents are now undergoing Phase I and Phase II trials. The timely and appropriate referral of patients for chemotherapy, however, is essential in order to optimise patients' care and use chemotherapy wisely. This article addresses many of these practical issues.
Stillbirth and early neonatal mortality in rural Central Africa
Authors: Engmann Cyril , Matendo Richard , Kinoshita Rinko , Ditekemena John , Moore Janet , Goldenberg Robert L. , Tshefu Antoinette , Carlo Waldemar A. , McClure Elizabeth M. , Bose Carl , Wright Linda L.
Published: February 2009

Objective

To develop a prospective perinatal registry that characterizes all deliveries, differentiates between stillbirths and early neonatal deaths (ENDs), and determines the ratio of fresh to macerated stillbirths in the northwest Democratic Republic of Congo.

Method

Birth outcomes were obtained from 4 rural health districts.

Results

A total of 8230 women consented, END rate was 32 deaths per 1000 live births, and stillbirth rate was 33 deaths per 1000 deliveries. The majority (75%) of ENDs and stillbirths occurred in neonates weighing 1500 g or more. Odds of stillbirth and END increased in mothers who were single or who did not receive prenatal care, and among premature, low birth weight, or male infants. The ratio of fresh to macerated stillbirths was 4:1.

Conclusion

Neonates weighing 1500 g or more at birth represent a group with a high likelihood of survival in remote areas, making them potentially amenable to targeted intervention packages. The ratio of fresh to macerated stillbirths was approximately 10‐fold higher than expected, suggesting a more prominent role for improved intrapartum obstetric interventions.
Perspectives on risk management in supply chains
Authors: Narasimhan Ram , Talluri Srinivas
Published: February 2009

Managing risk in supply chains is an important topic in supply chain management. The topic's importance is due to several industry trends currently in place: increase in strategic outsourcing by firms, globalizations of markets, increasing reliance on suppliers for specialized capabilities and innovation, reliance on supply networks for competitive advantage, and emergence of information technologies that make it possible to control and coordinate extended supply chains. This article identifies some important aspects of risk management in supply chains and summarizes the four articles that are in this special issue. This emerging area of research interest deserves considerable attention and it is our hope that the articles in this special issue would spur additional research on this important topic.
THE ROLE OFISIN THE ACQUISITION OF FINITENESS BY ADULT TURKISH LEARNERS OF DUTCH
Authors: van de Craats Ineke
Published: February 2009

This article deals with the interlanguage of adult second language (L2) learners acquiring finiteness. Due to the inaccessibility of bound inflectional morphology, learners use free morphology to mark a syntactic relationship as well as person and number features separately from the thematic verb, expressed by a pattern likethe manisgo. Results from longitudinally collected production data of Turkish learners of Dutch are reported and present evidence for the claim that (a) verb movement and production of inflectional morphology develop separately in various developmental steps and (b) finite forms in nonfinite contexts (and vice versa) are by-products of this development. Moreover, allis-patterns in different Germanic languages can be explained by the application of minimalist theory of verb movement and recent views on morphology.Is-patterns that correspond neither to the first language nor to the L2—a poverty-of-the-stimulus problem—turn out to be possible in other languages of the world and are constrained by Universal Grammar.
Personal reflections on love, death and suffering: My narrative of the final days of my husband's life
Authors: Sjolander Claire Turenne
Published: February 2009

John was weak, something that had begun quite suddenly the day before, and he needed my help in order to lift himself off the couch or to climb the stairs or to maneuver throughout the house. That morning, I had to cancel an invitation to accompany my parents on a trip out of town; John was too weak for me to leave him alone. I had been looking forward to leaving behind my responsibilities for a bit ever since my parents had suggested that I needed a break—and the prospect of a short trip into the Ottawa Valley for a few hours, a chance to live a little out from under the weight of everything at home, was so enticing. The decision not to go was both completely inescapable and incredibly hard, and I sobbed for a long time after getting off the phone with my Dad. For the first time since John had become ill, I let myself tell him how unfair this disease was and how its presence in our lives was affecting not only him, but me—how I felt that I no longer existed in any meaningful sense apart from the illness, how my entire days were defined by the need to manage his illness, his almost daily trips to the hospital, the constant appointments, the endless challenge of trying to get some nutrition into him, the need to take care of everything around the house and yet to stay on top of work.
Cyberbullying in Internet-Chatrooms – Wer sind die Täter?
Authors: Katzer Catarina , Fetchenhauer Detlef , Belschak Frank
Published: February 2009

Zusammenfassung. Das Phänomen des Bullying ist nicht mehr auf das schulische Umfeld begrenzt. Formen verbaler Gewalt und sozialer Manipulation spielen auch in Internet-Chatrooms eine bedeutende Rolle. Ziel der vorliegenden Untersuchung war ein Vergleich der Phänomene Schulbullying und Chatbullying. 1.700 Schüler verschiedener weiterführender Schulen aus Nordrhein-Westfalen nahmen an einer quantitativen Befragung teil. Erfasst wurden neben aktivem Bullying in Internet-Chatrooms und in der Schule auch Aspekte des Selbstkonzepts, des Familien- und Erziehungsklimas, der Schulsituation sowie Delinquenz, Gewalteinstellung und dissoziales Verhalten im Internet. Die Studie zeigt einen starken Zusammenhang zwischen der Täterschaft in der Schule und der Täterschaft in Internet-Chatrooms: Schulbullies sind signifikant häufiger als andere Jugendliche auch Chatbullies. Außerdem lassen sich Schulbullying und Chatbullying überwiegend durch die gleichen Prädiktoren vorhersagen.
Efficient full‐wave characterization of arrays of antennas embedded in finite dielectric volumes
Authors: Craeye Christophe , Gilles Thierry , Dardenne Xavier
Published: February 2009

This paper shows how the Macro Basis Functions (MBFs) approach can be applied to the solution of arrays of complex elements, made of metallic parts embedded in disconnected dielectric volumes. It is shown how the reduced system of equations can be obtained very efficiently with the help of a multipole approach. We also provide a subsequent formulation for the array impedance matrix and a fast method for the computation of embedded element patterns, with the help of a decomposition into a finite series of pattern multiplication problems, for which the fast Fourier transform can be exploited. Examples are provided for arrays of tapered slot antennas in separate dielectric boards. Comparisons are provided with brute‐force solutions for a 4 × 4 array and increasing number of MBFs, and with the infinite‐array solution for a 16 × 16 array. An appendix provides new insight into the problem of completeness of the MBFs bases by establishing a link between the MBF approach and Krylov subspaces.
Adjoint analysis of the 2007 all time Arctic sea‐ice minimum
Authors: Kauker F. , Kaminski T. , Karcher M. , Giering R. , Gerdes R. , Voßbeck M.
Published: February 2009

The past two decades saw a steady decrease of summer Arctic sea ice extent. The 2007 value was yet considerably lower than expected from extrapolating the long‐term trend. We present a quantitative analysis of this extraordinary event based on the adjoint of a coupled ocean‐sea ice model. This new approach allows to efficiently assess the sensitivity of the ice‐covered area in September 2007 with respect to any potential influence factor. We can trace back 86% of the ice area reduction to only four of these factors: May and June wind conditions, September 2‐meter temperature, and March ice thickness. Two thirds of the reduction are determined by factors that are already known at the end of June, suggesting a high potential for an early prediction.
Great geomagnetic storm of 9 November 1991: Association with a disappearing solar filament
Authors: Cliver E. W. , Balasubramaniam K. S. , Nitta N. V. , Li X.
Published: February 2009

We attribute the great geomagnetic storm on 8–10 November 1991 to a large‐scale eruption that encompassed the disappearance of a ∼25° solar filament in the southern solar hemisphere. The resultant soft X‐ray arcade spanned ∼90° of solar longitude. The rapid growth of an active region lying at one end of the X‐ray arcade appears to have triggered the eruption. This is the largest geomagnetic storm yet associated with the eruption of a quiescent filament. The minimum hourly Dst value of −354 nT on 9 November 1991 compares with a minimum Dst value of −161 nT for the largest 27‐day recurrent (coronal hole) storm observed from 1972 to 2005 and the minimum −559 nT value observed during the flare‐associated storm of 14 March 1989, the greatest magnetic storm recorded during the space age. Overall, the November 1991 storm ranks 15th on a list of Dst storms from 1905 to 2004, surpassing in intensity such well‐known storms as 14 July 1982 (−310 nT) and 15 July 2000 (−317 nT). We used the Cliver et al. and Gopalswamy et al. empirical models of coronal mass ejection propagation in the solar wind to provide consistency checks on the eruption/storm association.
Wavelet‐based ULF wave diagnosis of substorm expansion phase onset
Authors: Murphy Kyle R. , Rae I. Jonathan , Mann Ian R. , Milling David K. , Watt Clare E. J. , Ozeke Louis , Frey Harald U. , Angelopoulos Vassilis , Russell Christopher T.
Published: February 2009

Using a discrete wavelet transform with a Meyer wavelet basis, we present a new quantitative algorithm for determining the onset time of Pi1 and Pi2 ULF waves in the nightside ionosphere with ∼20‐ to 40‐s resolution at substorm expansion phase onset. We validate the algorithm by comparing both the ULF wave onset time and location to the optical onset determined by the Imager for Magnetopause‐to‐Aurora Global Exploration (IMAGE)–Far Ultraviolet Imager (FUV) instrument. In each of the six events analyzed, five substorm onsets and one pseudobreakup, the ULF onset is observed prior to the global optical onset observed by IMAGE at a station closely conjugate to the optical onset. The observed ULF onset times expand both latitudinally and longitudinally away from an epicenter of ULF wave power in the ionosphere. We further discuss the utility of the algorithm for diagnosing pseudobreakups and the relationship of the ULF onset epicenter to the meridians of elements of the substorm current wedge. The importance of the technique for establishing the causal sequence of events at substorm onset, especially in support of the multisatellite Time History of Events and Macroscale Interactions During Substorms (THEMIS) mission, is also described.
Ion conics and electron beams associated with auroral processes on Saturn
Authors: Mitchell D. G. , Kurth W. S. , Hospodarsky G. B. , Krupp N. , Saur J. , Mauk B. H. , Carbary J. F. , Krimigis S. M. , Dougherty M. K. , Hamilton D. C.
Published: February 2009

Ion conics accompanied by electron beams are observed regularly in Saturn's magnetosphere. The beams and conics are seen throughout the outer magnetosphere, on field lines that nominally map from well into the polar cap (Ldipole > 50) to well into the closed field region (Ldipole < 10). The electron beams and ion conics are often observed together but also sometimes separately. Typically, the ion conics are prominent at energies between about 30 keV and 200 keV. The electron beams extend from below the ∼20 keV lower energy threshold for the instrument to sometimes as high as 1 MeV. The electrons may be either unidirectional (upward) or bidirectional; the ions are exclusively unidirectional upward. The ion conics are usually seen in conjunction with enhanced broadband electromagnetic noise in the 10 Hz to few kHz frequency range. Most of the wave energy appears below the local electron cyclotron frequency, hence, is propagating in the whistler mode, although some extension to higher frequencies is sometimes observed, suggesting an electrostatic mode. Sometimes the particle phenomena and the broadband noise occur in pulses of roughly 5 min duration, separated by tens of minutes. At other times they are relatively steady over an hour or more. Magnetic signatures associated with some of the pulsed events are consistent with field aligned current structures. The ions are almost exclusively light ions (H, H2, H3, and/or He) with only occasional hints of oxygen or other heavier species, suggesting an ionospheric source. Taken together, the observations are strikingly similar to those made at Earth in association with auroral zone downward sheet currents, except that in the case of Saturn the particle energies are 20 to 100 times higher.
First principles investigation of the structural and elastic properties of hydrous wadsleyite under pressure
Authors: Tsuchiya Jun , Tsuchiya Taku
Published: February 2009

In order to clarify the effect of protonation of wadsleyite under high‐pressure conditions, we determined defect structures of Mg1.875SiO4H0.25 (1Mg2+ ↔ VMg2− + 2H+, 1.65 wt % H2O), Mg1.75SiO4H0.5 (2Mg2+ ↔ 2VMg2− + 4H−, 3.3 wt % H2O) hydrous wadsleyite and their elastic properties by means of the density functional first principles method. Structural optimization calculations indicate that the most stable structures have monoclinic symmetry with magnesium M3 site vacancies. Protons are found to bond to the O1 site to align the OH dipoles along the edges of M3 vacancies. Calculated elastic constants, bulk and shear moduli, are found to decrease almost linearly with increasing water content but to increase linearly with increasing pressure. At 15 GPa and static 0 K condition, incorporation of 3.3 wt % H2O into wadsleyite, which corresponds to the maximum solubility of hydrous wadsleyite, reduces VP and VS by about 3.9 and 4.8%, respectively. This indicates that 1 wt % H2O hydration of wadsleyite corresponds to the temperature effects on bulk and shear moduli about 430 K (0 GPa) to 340 K (20 GPa) and 350 K (0 GPa) to 290 K (20 GPa), respectively. The transversely isotropic aggregates demonstrate largest positive polarization anisotropy VSH − VSV when the c axis aligns vertically in both dry and wet cases.