bluuebunny/crossref_metadata_2025 huggingface dataset:
Anisotropy of Local Stress Tensor Leads to Line Tension
Authors: Shao Mingzhe , Wang Jianjun , Zhou Xin
Published: April 2015

Line tension of three-phase contact lines is an important physical quantity in understanding many physical processes such as heterogeneous nucleation, soft lithography and behaviours in biomembrane, such as budding, fission and fusion. Although the concept of line tension was proposed as the excess free energy in three-phase coexistence regions a century ago, its microscopic origin is subtle and achieves long-term concerns. In this paper, we correlate line tension with anisotropy of diagonal components of stress tensor and give a general formula of line tension. By performing molecular dynamic simulations, we illustrate the formula proposed in Lennard-Jones gas/liquid/liquid and gas/liquid/solid systems and find that the spatial distribution of line tension can be well revealed when the local distribution of stress tensor is considered.
Effect of bending deformation on photovoltaic performance of flexible graphene/Ag electrode-based polymer solar cells
Authors: Moaven Shiva , Naji Leila , Taromi Faramarz Afshar , Sharif Farhad
Published: April 2015

Photovoltaic characteristics of flexible graphene/Ag electrode – based polymer solar cells as a function of electrode thickness under bending deformation.
“He'll Grow out of it Soon—Won't He?”—The Characteristics of Older Children's Speech When They Do—and Don't—Grow out of it
Authors: Wren Yvonne
Published: April 2015

Speech sound disorder is a common reason for referral to speech and language therapy services in the early years. While for some children, their difficulties are transitory and they either respond to intervention or their difficulties resolve, for others, their speech sound difficulties evolve into persistent speech disorder (PSD). The purpose of this article is to provide information on the features of PSD and how to assess children with PSD in order to identify the full range and limits of their speech sound system. Reference is made to ALSPAC, a large longitudinal population study, regarding prevalence, possible subtypes, and risk factors for PSD.
Fast wavelength calibration method for spectrometers based on waveguide comb optical filter
Authors: Yu Zhengang , Huang Meizhen , Wang Yang , Zou Ye , Sun Zhenhua , Cao Zhuangqi
Published: April 2015

A novel fast wavelength calibration method for spectrometers based on a standard spectrometer and a double metal-cladding waveguide comb optical filter (WCOF) is proposed and demonstrated. By using the WCOF device, a wide-spectrum beam is comb-filtered, which is very suitable for spectrometer wavelength calibration. The influence of waveguide filter’s structural parameters and the beam incident angle on the comb absorption peaks’ wavelength and its bandwidth are also discussed. The verification experiments were carried out in the wavelength range of 200–1100 nm with satisfactory results. Comparing with the traditional wavelength calibration method based on discrete sparse atomic emission or absorption lines, the new method has some advantages: sufficient calibration data, high accuracy, short calibration time, fit for produce process, stability, etc.
Effect of molecular nitrogen impurity on the photoluminescence of fullerite C60
Authors: Zinoviev P. V. , Zoryansky V. N. , Meleshko V. V. , Stetsenko Yu. E.
Published: April 2015

Polycrystalline samples of fullerite C60 with different concentrations of molecular nitrogen impurity are studied by luminescence spectroscopy at temperatures of 20–230 K. The photoluminescence characteristics of the C60-N2 solutions vary significantly. At T = 20 K there is a significant contribution to the luminescence from emission centers (“deep X-traps”) determined by the concentration of N2 molecules in octahedral voids of the fcc C60 lattice. The experimentally observed differences in the effect of nitrogen impurities on the structural and luminescence characteristics of C60-N2 solutions show that the filling of the lattice voids into the depth (from the surface) of the samples is substantially inhomogeneous. The temperature dependences of the integrated emission intensity from samples with different nitrogen concentrations are studied. N2 molecules are found to have little effect on the formation of fullerite orientational glass. A tendency for the vitrification temperature of these C60-N2 solutions to fall with increasing impurity concentration is observed experimentally.
Blow-up phenomena for polytropic equation with inhomogeneous density and source
Authors: Novruzov Emil
Published: April 2015

The subject of this investigation is the blow-up phenomena of the positive solutions of the mixed problem for the one-dimensional polytropic filtration equation with inhomogeneous density and source. It is shown that under certain conditions on the nonlinearities and data, blow-up will occur at some finite time. Note that the technique applied for the proof does not use the Zel’dovich-Kompaneets-Barenblatt solutions, since the construction of such type of function is more complicated in our case. Therefore, we obtain a result by multiplying on a special factor which has convenient properties. In particular, by choosing the parameters of the factor and using the properties of the solution, we obtain the inequality which allows us to show the blow up phenomena.
An analytical and numerical study on the start-up flow of slightly rarefied gases in a parallel-plate channel and a pipe
Authors: Avramenko A. A. , Tyrinov A. I. , Shevchuk I. V.
Published: April 2015

The paper presents results of an investigation of the response of an incompressible fluid in a circular micropipe and a parallel-plate microchannel to a sudden time-independent pressure drop. Solutions of the problem were obtained analytically using the Laplace transform technique and numerically using the lattice Boltzmann method. The unsteady velocity profiles in the pipe and in the channel were obtained with the help of the infinite series solutions validated against numerical simulations. In line with the expectations, the flow asymptotically tends to the fully developed pattern, which is attained quicker for smaller Knudsen numbers. The solution enabled also obtaining relations to estimate the hydraulic resistance coefficient.
Absence of low temperature phase transitions and enhancement of ferroelectric transition temperature in highly strained BaTiO3 epitaxial films grown on MgO Substrates
Authors: Kumar Satish , Kumar Dhirendra , Sathe V. G. , Kumar Ravi , Sharma T. K.
Published: April 2015

Recently, a large enhancement in the ferroelectric transition temperature of several oxides is reported by growing the respective thin films on appropriate substrates. This phenomenon is correlated with high residual strain in thin films often leading to large increase in the tetragonality of their crystal structure. However, such an enhancement of transition temperature is usually limited to very thin films of ∼10 nm thickness. Here, we report growth of fully strained epitaxial thin films of BaTiO3 of 400 nm thickness, which are coherently grown on MgO substrates by pulsed laser deposition technique. Conventional high resolution x-ray diffraction and also the reciprocal space map measurements confirm that the film is fully strained with in-plane tensile strain of 5.5% that dramatically increases the tetragonality to 1.05. Raman measurements reveal that the tetragonal to cubic structural phase transition is observed at 583 K, which results in an enhancement of ∼200 K. Furthermore, temperature dependent Raman studies on these films corroborate absence of all the low temperature phase transitions. Numerical calculations based on thermodynamical model predict a value of the transition temperature that is greater than 1500 °C. Our experimental results are therefore in clear deviation from the existing strain dependent phase diagrams.
A ferromagnetic quantum critical point in heavy-fermion iron oxypnictide CeFe1−xCrxPO
Authors: Okano T. , Kitao S. , Seto M. , Atou T. , Itoh M. , Matoba M. , Kamihara Y.
Published: April 2015

We report crystallographic and magnetic properties of layered iron oxypnictide CeFe1−xCrxPO (x = 0.000–0.692). Interlayer distances between Ce2O2 and (Fe1−xCrx)2P2 layers increase as a function of x, suggesting suppression of Kondo coupling among hybridized conducting orbitals and localized Ce 4f orbitals. CeFe1−xCrxPO (x = 0.100–0.384) exhibits finite ferromagnetic transition temperatures (Tcurie) obtained by Arrott plots, although 57Fe Mössbauer spectra reveal paramagnetic Fe sublattice at T ≥ 4.2 K. These results indicate that the ferromagnetic phase transitions of samples are mainly due to Ce sublattice. For the samples with x ≥ 0.500, no ferromagnetic order is observed down to 2 K. These results verify that ferromagnetic quantum critical points of CeFe1−xCrxPO appear at 0.045 ≤ x ≤ 0.100 and 0.384 ≤ x ≤ 0.500.
The effects of local exchange anisotropy in a tetranuclear molecular complex with D4h symmetry
Authors: Zhuravlev A. V.
Published: April 2015

Exact diagonalization technique was applied to a tetranuclear molecular magnet of D4h symmetry with local anisotropic exchange interactions. The spin Hamiltonian of the complex containing four ions with spin s = 1/2 with isotropic ferromagnetic interaction of nearest neighbors was supplemented with local interactions—Dzyaloshinskii–Moria interaction as well as axial and azimuthal exchange anisotropy. The evolution of the energy levels of the complex was investigated as a function of local parameters of the spin Hamiltonian, taking into account the symmetry of the complex. The influence of mixing the wave functions both with the same and different spin states of the levels belonging to different multiplets (spin mixing) was considered. It was shown that strong spin mixing in a cluster of D4h symmetry can only exist due to the local azimuthal anisotropy.
Diethylaluminium Azide: A Versatile Reagent in Organic Synthesis
Authors: Monticelli Serena , Pace Vittorio
Published: April 2015

The unique properties of diethylaluminium azide – arising from the Lewis acid aluminium and the nucleophilicity of the azide – make it a versatile reagent in organic synthesis. Ring-opening of epoxides, Michael-type additions, synthesis of acyl azides, and functionalizations of fullerene C60 will be discussed. Among the recently described uses of the reagent, particular attention will be devoted to the powerful Sedelmeier’s method to access 1H-tetrazol starting from nitriles.
Fire history of a mixed conifer forest on the Mogollon Rim, northern Arizona, USA
Authors: Huffman David W. , Zegler Thomas J. , Fulé Peter Z.
Published: April 2015

It has been suggested that large, high-severity fires historically structured warm–dry mixed conifer forests in the American South-west. To test this, we reconstructed fire regime characteristics of an 1135-ha (11.3 km2) mixed conifer landscape in northern Arizona using complementary approaches. We analysed composite fire intervals, point fire intervals, natural fire rotation, landscape characteristics and forest age structure. Composite analysis of cross-dated fire scars from 133 trees indicated a mean fire interval (MFI) of 2.0–8.5 years between 1670 and 1879. Frequent fires halted abruptly after 1879. Mean point fire interval (MPFI) was 11.8 years and ranged 2–61 years. Mean fire rotation was 14.4 years. Density of most occurring tree species increased dramatically after fire regime disruption, with south-western white pine (Pinus strobiformis) and white fir (Abies concolor) showing large numerical gains. Tree establishment patterns compared with widespread fire dates did not suggest historical high-severity fires at the site level. Although strong evidence of high-severity fire at finer scales was lacking, spatial locations of ‘young’ plots suggested the possibility of historical high-severity disturbances ≤25 ha in size. The historical fire regime on this landscape was one of high-frequency, low-severity fires. Current conditions call for restoration of forest structure and function.
A Comparison of Three Anatomical Structures for Estimating Age in a Slow-Growing Subarctic Population of Lake Whitefish
Authors: Zhu Xinhua , Wastle Rick J. , Howland Kimberly L. , Leonard Deanna J. , Mann Susan , Carmichael Theresa J. , Tallman Ross F.
Published: April 2015

It has been well documented in previous research that otoliths are the preferred hard structure for estimating age in coregonids. However, the slower growth due to short growing seasons experienced by populations in the subarctic region of the boreal zone may alter the utility of alternative nonlethal structures for estimating age. We compared the three most commonly used age estimation structures (otoliths, pectoral fin rays, and scales) for Lake Whitefish Coregonus clupeaformis in a northern (above 50°N) population from Great Slave Lake. This study provides new perspectives regarding the use of different aging structures with fish populations typical of subarctic and arctic environments. Results of ANOVA showed that reader confidence, within-reader precision, and the age estimates themselves were all affected by age structure; reader confidence also varied with age-class. Reader confidence was highest for age estimates from otoliths, followed by pectoral fin rays and then scales. Similarly, within-reader precision (as measured by CVs) was highest for age estimates from otoliths, followed by scales and then pectoral fin ray sections. Pairwise comparisons between age estimates from otoliths and those from scales or pectoral fin rays indicated no significant differences when fish were younger than 10 years (scales) or 12 years (fin rays), suggesting that these nonlethal structures could be conservatively used to reliably estimate ages of younger (<10 years) and smaller (≤300 mm FL) Lake Whitefish. Of particular significance are the findings that (1) divergence between scale and otolith age estimates is delayed by 5–6 years relative to more southerly populations; and (2) in contrast to examples from southern populations, fin rays do not offer a suitable nonlethal alternative for estimating ages of older Lake Whitefish (>11 years).

Received March 4, 2014; accepted December 3, 2014
Correlations between psychometric schizotypy, scan path length, fixations on the eyes and face recognition
Authors: Hills Peter J. , Eaton Elizabeth , Pake J. Michael
Published: April 2015

Psychometric schizotypy in the general population correlates negatively with face recognition accuracy, potentially due to deficits in inhibition, social withdrawal, or eye-movement abnormalities. We report an eye-tracking face recognition study in which participants were required to match one of two faces (target and distractor) to a cue face presented immediately before. All faces could be presented with or without paraphernalia (e.g., hats, glasses, facial hair). Results showed that paraphernalia distracted participants, and that the most distracting condition was when the cue and the distractor face had paraphernalia but the target face did not, while there was no correlation between distractibility and participants’ scores on the Schizotypal Personality Questionnaire (SPQ). Schizotypy was negatively correlated with proportion of time fixating on the eyes and positively correlated with not fixating on a feature. It was negatively correlated with scan path length and this variable correlated with face recognition accuracy. These results are interpreted as schizotypal traits being associated with a restricted scan path leading to face recognition deficits.
Healthy organization: analysing its meaning based on the HERO Model / Organizaciones saludables: analizando su significado desde el Modelo HERO
Authors: Acosta Hedy , Cruz-Ortiz Valeria , Salanova Marisa , Llorens Susana
Published: April 2015

The aim of this study is to analyse the meaning of healthy organization from an empirical-theoretical perspective based on the HERO Model ( HEalthy & Resilient Organizations). Analyses were performed by four independent judges on 14 interviews carried out with 14 CEOs or human resources managers in 14 Spanish organizations using content analysis. Qualitative results show: (1) a partial overlap in the categories proposed by the theoretical model (based on the concordance index, Cohen’s Kappa and ICC); and (2) that the empirical definition mainly focuses on employees’ psychosocial health as a key element of the meaning of healthy organization. Finally, categorical matrixes provide evidence of subcategories emanating from the key elements that comprise a healthy organization. Results as well as theoretical and practical implications are discussed based on the HERO Model.
A constraint variational problem arising in stellar dynamics
Authors: Hadzic Mahir
Published: April 2015

We use the compactness result of A. Burchard and Y. Guo to analyze the reduced ‘energy’ functional arising naturally in the stability analysis of steady states of the Vlasov-Poisson system (cf. Sánchez and Soler, to appear, and Hadžić, 2005). We consider the associated variational problem and present a new proof that puts it in the general framework for tackling the variational problems of this type, given by Y. Guo and G. Rein (cf. Rein, 2005 and Rein, 2002).
Decay of the electromagnetic field in a Maxwell Bloch system
Authors: Jochmann Frank
Published: April 2015

This paper is concerned with the initial-boundary value problem for the Maxwell-Bloch system which describes the propagation of electromagnetic waves in a polarized quantum-mechanical medium with two energy levels. The main goal is the investigation of the large-time asymptotic behavior of the solutions if there are no relaxation terms in the equations governing the polarization field and the density.
Higher derivatives and the inverse derivative of a tensor-valued function of a tensor
Authors: Norris Andrew
Published: April 2015

The

n

t
h

n^{th}

derivative of a tensor-valued function of a tensor is defined by a finite number of coefficients each with closed form expression.
Asymptotic behavior of a nonisothermal Ginzburg-Landau model
Authors: Grasselli Maurizio , Wu Hao , Zheng Songmu
Published: April 2015

We analyze a system of nonlinear parabolic equations which describes the evolution of an order parameter

f
f

and the relative temperature

v
v

in a superconducting material occupying a bounded domain

Ω
⊂

R

n

\Omega \subset {\mathbb R}^n

,

n
≤
3

n\leq 3

. Here the dependent variable

f
f

is subject to the homogeneous Neumann boundary condition, while

v
v

is equal to a time-dependent Dirichlet datum

u
~

\tilde u

on the boundary. Therefore, the corresponding dynamical system is nonautonomous. Our main goal is to analyze the asymptotic behavior of its solutions. We first show that the system has a bounded absorbing set and a global attractor which are uniform with respect to a sufficiently general class of

u
~

\tilde u

. Then, we give sufficient conditions on

u
~

\tilde u

which ensure the convergence of a given trajectory to a single stationary state and we estimate the convergence rate. Finally, we demonstrate the existence of an exponential attractor of finite fractal dimension for quasi-periodic or stabilizing boundary data

u
~

\tilde u

.
Stability of random-switching systems of differential equations
Authors: Zhu C. , Yin G. , Song Q.
Published: April 2015

This work is devoted to the stability of random-switching systems of differential equations. After presenting the formulation of random-switching systems, the notion of stability is recalled, and sufficient conditions in terms of the Liapunov function are presented. Then easily verifiable conditions for stability and instability of systems arising in approximation are established. Using a logarithm transformation, necessary and sufficient conditions are derived for systems that are linear in the continuous state component. Several examples are provided as demonstrations. Among other things, a somewhat different behavior from the well-known Hartman-Grobman theorem is observed.
Minimax entropy solutions of ill-posed problems
Authors: Greensite Fred
Published: April 2015

Convergent methodology for ill-posed problems is typically equivalent to application of an operator dependent on a single parameter derived from the noise level and the data (a regularization parameter or terminal iteration number). In the context of a given problem discretized for purposes of numerical analysis, these methods can be viewed as resulting from imposed prior constraints bearing the same amount of information content. We identify a new convergent method for the treatment of certain multivariate ill-posed problems, which imposes constraints of a much lower information content (i.e., having much lower bias), based on the operator’s dependence on many data-derived parameters. The associated marked performance improvements that are possible are illustrated with solution estimates for a Lyapunov equation structured by an ill-conditioned matrix. The methodology can be understood in terms of a Minimax Entropy Principle, which emerges from the Maximum Entropy Principle in some multivariate settings.
Modelling supply networks with partial differential equations
Authors: D’Apice C. , Manzo R. , Piccoli B.
Published: April 2015

A continuum-discrete model for supply networks is introduced. The model consists of a system of conservation laws: a conservation law for the goods density and an evolution equation for the processing rate. The network is formed by subchains and nodes at which, motivated by real cases, two routing algorithms are considered: the first maximizes fluxes taking into account the goods’ final destinations, while the second maximizes fluxes without constraints. We analyze waves produced at nodes and equilibria for both algorithms, relating the latter to production rates in real supply networks. In particular, we show how the model can reproduce the well-known Bullwhip effect.
Structural conditions for full MHD equations
Authors: Kwon Bongsuk
Published: April 2015

In this paper, we investigate the characteristic structure of the full equations of magnetohydrodynamics (MHD) and show that it satisfies the hypotheses of a general variable-multiplicity stability framework introduced by Métivier and Zumbrun, thereby extending to the general case various results obtained by Métivier and Zumbrun for the isentropic equations of MHD.
On the artificial compressibility method for the Navier-Stokes-Fourier system
Authors: Donatelli Donatella
Published: April 2015

This paper deals with the artificial compressibility approximation method adapted to the incompressible Navier Stokes Fourier system. Two different types of approximations will be analyzed: one for the full Navier Stokes Fourier system (or the so-called Rayleigh-Benard equations) where viscous heating effects are considered and the other for when the dissipative function

S

:
∇
u

\mathbb {S}:\nabla u

is omitted. The convergence of the approximating sequences is achieved by exploiting the dispersive properties of the wave equation structure of the pressure of the approximating system.
Analyticity of transmission problem to thermoelastic plates
Authors: Sare Hugo , Muñoz Rivera Jaime
Published: April 2015

In this paper we consider an oscillation model to a plate comprised of two different thermoelastic materials; that is, we study a transmission problem to thermoelastic plates. Our main result is to prove that the corresponding semigroup associated to this problem is of analytic type.
Hilbert problem for a multiply connected circular domain and the analysis of the Hall effect in a plate
Authors: Antipov Y. , Silvestrov V.
Published: April 2015

In this paper we analyze the Hilbert boundary-value problem of the theory of analytic functions for an

(
N
+
1
)

(N+1)

-connected circular domain. An exact series-form solution has already been derived for the case of continuous coefficients. Motivated by the study of the Hall effect in a multiply connected plate we extend these results by examining the case of discontinuous coefficients. The Hilbert problem maps into the Riemann-Hilbert problem for symmetric piece-wise meromorphic functions invariant with respect to a symmetric Schottky group. The solution to this problem is derived in terms of two analogues of the Cauchy kernel, quasiautomorphic and quasimultiplicative kernels. The former kernel is known for any symmetric Schottky group. We prove the existence theorem for the second (quasimultiplicative) kernel for any Schottky group (its series representation is known for the first class groups only). We also show that the use of an automorphic kernel requires the solution to the associated real analogue of the Jacobi inversion problem, which can be bypassed if we employ the quasiautomorphic and quasimultiplicative kernels. We apply this theory to a model steady-state problem on the motion of charged electrons in a plate with

N
+
1

N+1

circular holes with electrodes and dielectrics on the walls when the conductor is placed at a right angle to the applied magnetic field.
Global existence in nonlinear hyperbolic thermoelasticity with radial symmetry
Authors: Irmscher Tilman
Published: April 2015

In this paper we consider a nonlinear system of hyperbolic thermoelasticity in two or three dimensions with Dirichlet boundary conditions in the case of radial symmetry. We prove the global existence of small, smooth solutions and the exponential stability.
Flocking and synchronization of particle models
Authors: Ha Seung-Yeal , Lattanzio Corrado , Rubino Bruno , Slemrod Marshall
Published: April 2015

In this note, we present a multi-dimensional flocking model rigorously derived from a vector oscillatory chain model and study the connection between the Cucker-Smale flocking model and the Kuramoto synchronization model appearing in the statistical mechanics of nonlinear oscillators. We provide an alternative direct approach for frequency synchronization to the Kuramoto model as an application of the flocking estimate for the Cucker-Smale model.
Waiting time phenomena forced by critical boundary conditions in classical diffusion problems
Authors: Fasano A. , Mancini A. , Primicerio M. , Zaltzman B.
Published: April 2015

This paper revisits some very classical initial-boundary value problems for parabolic equations, providing simple examples in which the occurrence of flux discontinuities at the boundary when the unknown function reaches some critical value may give rise to a waiting time phenomenon. A physical interpretation could be a modification of the surface of the considered body taking place at the mentioned critical value, affecting the way the body interacts with the surroundings. The waiting time, whose length (finite or infinite) is a priori unknown allows the system to evolve gradually through the critical state. Some numerical simulations are also presented.
Impulsive displacement of a liquid in a pipe at high Reynolds numbers
Authors: Kleinstein Gerald
Published: April 2015

We consider the problem of an impulsive displacement of a liquid, originally at rest in a circular pipe, which is displaced by another liquid. The purpose of this analysis is to show that at a sufficiently high inertia the initial essentially inviscid motion can be extended to cover the entire displacement process, thus creating an inviscid window to which an inviscid analysis can be applied. We simplify the problem first, by considering a 1-liquid problem where the displacing liquid and displaced liquid are the same. We identify two characteristic times in this problem: the time it takes an inviscid liquid to be displaced, and the time it takes a viscous liquid to attain a steady state. Taking the ratio of the two defines the Reynolds number for the problem and we show that the motion becomes essentially inviscid once the Reynolds number is sufficiently high. We obtain the general solution of the 1-liquid problem which determines the nondimensional viscous displacement time as a function of the Reynolds number. We derive from the general solution: a critical Reynolds number above which the motion remains unsteady throughout the entire displacement process, and a formula which determines quantitatively whether applying an inviscid analysis to the 1-liquid viscous problem at a given Reynolds number is admissible within an acceptable error tolerance. We also show that at the limit the Reynolds number approaches infinity the viscous displacement time approaches the inviscid displacement time and that the velocity profile and the shape of the material surface separating the displacing from the displaced liquid approach their counterpart in the inviscid solution. Second, based on these results we propose that an inviscid solution is applicable to the 2-liquid viscous problem once the condition of a high Reynolds number is independently met by the two participating liquids. We obtain the solution to the inviscid 2-liquid displacement problem and calculate various examples. Finally, we present a stability analysis of the flat interface between the two inviscid liquids, which shows which of the examples is stable, neutrally stable, or unstable. The paucity of data for an impulsive displacement in the high Reynolds number range makes quantitative comparisons difficult. However, the excellent agreement obtained between the critical Reynolds number derived in this analysis and the result obtained in a numerical analysis of the viscous 2-liquid problem elsewhere constitutes at least a partial validation of the theory. Additional confirmation is obviously recommended.
Multiple solutions for hydromagnetic flow of a second grade fluid over a stretching or shrinking sheet
Authors: Van Gorder Robert , Vajravelu K.
Published: April 2015

We study a class of fourth-order nonlinear differential equations arising in the hydromagnetic flow of a second grade fluid over a stretching or shrinking sheet. Explicit exact solutions are obtained. Furthermore we show that the differential equation may admit zero or one or two physically meaningful solutions depending on the values of the physical parameters of the model. As a special case, we recover the single or the dual solutions and compare them with the available results in the literature. Also, the obtained multiple solutions for several sets of values of the parameters are presented through tables and graphs, and the qualitative behaviors are discussed.
Loss of control of motions from initial data for pending capillary liquid
Authors: Massari Umberto , Padula Mariarosaria , Shimizu Senjo
Published: April 2015

First,the problem of stabilityof an equilibrium figureF∗F_*for an abstract systemis reduced to the sign ofthe difference between the energy of the perturbed motion at initial time, and that ofF∗F_*. All control conditions are only sufficient conditions to ensure nonlinear stability.

Second, employing the local character of the nonlinear stability, some nonlinear instability theorems are proven by a direct method.

Third, the definition of loss of control from initial data for motionsFFis introduced. A class of equilibrium figuresF∗F_*is constructed such that:F∗F_*is nonlinearly stable; the motions, corresponding to initial data sufficiently far fromF∗F_*, cannot be controlled by their initial data for all time. A lower bound is computed for the norms of initial data above which the loss of control from initial data occurs.
Corrigendum for “Energy balance for viscoelastic bodies in frictionless contact”
Authors: Stewart David
Published: April 2015

The proof in “Energy balance for viscoelastic bodies in frictionless contact” of an energy balance has a crucial flaw that renders the proof incorrect. At present no correction for this flaw is known.
Dynamic pattern formation in Swift-Hohenberg equations
Authors: Hoang Tung , Hwang Hyung Ju
Published: April 2015

In this paper we study nonlinear instability in the Swift-Hohenberg equation. The short-time pattern formation under the fully nonlinear setting is rigorously characterized. For unstable constant equilibria, we investigate the nonlinear dynamics of patterns which occur within the time interval of existence.
Chromatids segregate without centrosomes duringCaenorhabditis elegansmitosis in a Ran- and CLASP-dependent manner
Authors: Nahaboo Wallis , Zouak Melissa , Askjaer Peter , Delattre Marie
Published: April 2015

During mitosis, chromosomes are connected to a microtubule-based spindle. Current models propose that displacement of the spindle poles and/or the activity of kinetochore microtubules generate mechanical forces that segregate sister chromatids. Using laser destruction of the centrosomes during Caenorhabditis elegans mitosis, we show that neither of these mechanisms is necessary to achieve proper chromatid segregation. Our results strongly suggest that an outward force generated by the spindle midzone, independently of centrosomes, is sufficient to segregate chromosomes in mitotic cells. Using mutant and RNAi analysis, we show that the microtubule-bundling protein SPD-1/MAP-65 and BMK-1/kinesin-5 act as a brake opposing the force generated by the spindle midzone. Conversely, we identify a novel role for two microtubule-growth and nucleation agents, Ran and CLASP, in the establishment of the centrosome-independent force during anaphase. Their involvement raises the interesting possibility that microtubule polymerization of midzone microtubules is continuously required to sustain chromosome segregation during mitosis.
No axions from the Sun
Authors: Roncadelli M. , Tavecchio F.
Published: April 2015

Preliminary evidence of solar axions in XMM–Newton observations has quite recently been claimed by Fraser et al. as an interpretation of their detection of a seasonally-modulated excess of the X-ray background. Within such an interpretation, these authors also estimate the axion mass to be ma ≃ 2.3 × 10−6 eV. Since an axion with this mass behaves as a cold dark matter particle, according to the proposed interpretation the considered detection directly concerns cold dark matter as well. So, the suggested interpretation would lead to a revolutionary discovery if confirmed. Unfortunately, we have identified three distinct problems in this interpretation of the observed result of Fraser et al. which ultimately imply that the detected signal – while extremely interesting in itself – cannot have any relation with hypothetical axions produced by the Sun. Thus, a physically consistent interpretation of the observed seasonally-modulated X-ray excess still remains an exciting challenge.
Transcriptional Changes in CD8+ T Cells During Antiretroviral Therapy Intensified With Raltegravir
Authors: Ouyang Zhengyu , Buzon Maria J. , Zheng Lu , Sun Hong , Yu Xu G. , Bosch Ronald J. , Mellors John W. , Eron Joseph J. , Gandhi Rajesh T. , Lichterfeld Mathias
Published: April 2015

Background.  Intensification of antiretroviral therapy with raltegravir does not affect levels of residual human immunodeficiency virus (HIV)-1 viremia, but it has led to increased levels of episomal HIV-1 DNA in some patients, suggesting antiviral activity against otherwise unresponsive components of the viral reservoir. Effects of raltegravir on host cells remain less well understood.

Methods.  We used comprehensive and unbiased microarray-based transcriptional profiling to analyze gene expression changes in CD8+ T cells from participants in a randomized clinical trial (AIDS Clinical Trials Group [ACTG] A5244) comparing raltegravir-intensified to nonintensified antiretroviral therapy.

Results.  Although raltegravir intensification failed to induce statistically significant changes in HIV-1 DNA or residual plasma viremia, we observed significant increases in the expression intensity of 121 host gene transcripts. In functional annotations of these transcripts, we found that they were mainly involved in glucose and carbohydrate metabolism, immune regulation, control of cell proliferation, and tumor suppression. Two of the raltegravir-responsive gene transcripts were statistically correlated with levels of residual HIV-1 RNA, but none of the remaining 119 transcripts were associated with immunologic or virologic characteristics of the study patients.

Conclusions.  Together, these findings demonstrate that raltegravir intensification can induce previously unrecognized, statistically significant gene expression changes in host CD8+ T lymphocytes.
Ubiquitylation, neddylation and the DNA damage response
Authors: Brown Jessica S. , Jackson Stephen P.
Published: April 2015

Failure of accurate DNA damage sensing and repair mechanisms manifests as a variety of human diseases, including neurodegenerative disorders, immunodeficiency, infertility and cancer. The accuracy and efficiency of DNA damage detection and repair, collectively termed the DNA damage response (DDR), requires the recruitment and subsequent post-translational modification (PTM) of a complex network of proteins. Ubiquitin and the ubiquitin-like protein (UBL) SUMO have established roles in regulating the cellular response to DNA double-strand breaks (DSBs). A role for other UBLs, such as NEDD8, is also now emerging. This article provides an overview of the DDR, discusses our current understanding of the process and function of PTM by ubiquitin and NEDD8, and reviews the literature surrounding the role of ubiquitylation and neddylation in DNA repair processes, focusing particularly on DNA DSB repair.
The ties that bind? Online musicians and their fans
Authors: Daellenbach Kate , Kusel Rachael , Rod Michel
Published: April 2015

Purpose

– The purpose of this study is to examine the relationships between musician’s social network sites (SNS), the tie that fans may develop via these sites, and music acquisition, via legal and illegal means.

Design/methodology/approach

– A quantitative approach was taken, gathering 352 responses from young adults via an online survey.

Findings

– Perceptions of interactivity and sincerity on musicians’ SNS are found to lead to stronger ties, enhancing the fan’s feeling of closeness to the musician, the fan’s inclination to spread positive word-of-mouth, and the time a fan spends on the site. Pathways are found between the fan activity, sense of closeness and time spent on the SNS. In terms of acquisition, the tie strength indicator of time spent on the SNS holds a positive relationship with purchase intent. While a sense of closeness holds a negative relationship to illegal downloading activity, the fan’s activity recommending the musician has a positive influence on illegal downloading.

Research limitations/implications

– Limitations of this study include a limited amount of information on the musician and extent of fandom, suggesting future research to tease out the effects of SNS on fans with varying levels of existing commitment to musicians.

Practical implications

– Stronger ties between fans and musicians may be developed via interactive and sincere SNS. Activities which encourage the fan to give recommendations and spread positive word-of-mouth are especially influential in driving purchase intent.

Originality/value

– These results provide theoretical and practical implications in relation to how SNS may influence the online fan-celebrity “tie” and music acquisition – three elements which have not to date been examined.
Benchmarking of TQM: the case of Hikma Pharmaceuticals company
Authors: Sweis Rateb J , Al-Ghawi Hala Jamal , AlSaleh Noor Abdel-Aziz , Al-Zu'bi Zu'bi M.F , Obeidat Bader Y
Published: April 2015

Purpose

– The purpose of this paper is to gain a better understanding of internal benchmarking through the evaluation of quality management in two quality departments (Quality Assurance (QA) and Quality Control (QC)) in a pharmaceutical company by utilizing total quality index (TQI).

Design/methodology/approach

– In order to achieve the above-mentioned purpose a structured questionnaire was used to assess the gap between the ideal and current status of the quality management system. The mean differences between the current and ideal states for the eight critical factors were compared for the two departments using t-test.

Findings

– There is difference in the actual and ideal scores on three out of eight critical factors between the QA and QC departments.

Practical implications

– The internal benchmarking process which was applied in this case study can be applied in other pharmaceutical companies in order to improve the status of the quality management system and achieve competitive advantage.

Originality/value

– Benchmarking of total quality management (TQM) can improve the performance of organizations. The benchmarking tool used in this study TQI is an information technology-supported tool that helps managers assess a TQM program by enabling the cost-effective measurement of key organizational processes. TQI measures the ideal and actual quality management along eight critical factors synthesized by Saraph et al. (1989).
Information technology sector in India and gender inclusivity
Authors: Dutta Gupta Sangita , Raychaudhuri Ajitava , Haldar Sushil Kr.
Published: April 2015

Purpose

– This paper aims to address the issue of gender inclusivity in the information technology (IT) sector of India. The main objective of the paper is to find out the factors influencing female participation in the IT industry. It proposes some policy initiatives to support involvement of women in adequate proportion in the workforce.

Design/methodology/approach

– The study uses a unique set of data from 63 IT companies from three big cities of Delhi-National Capital Region (NCR), Bengaluru and Kolkata. An ordered logit model is applied to find out the determinants of female absorption in the IT industry. ANOVA is used to study the variations between and within the IT industry of female labor force participation.

Findings

– Result reveals that the percentage and mobility of female employees in an organization does not depend on the turnover or the total number of skilled employees in the organization. It depends on the location.

Research limitations/implications

– The main limitation of the paper is that many IT companies do not want to reveal data about the percentage of female employees. If more companies could have been included, more accurate results could have been found.

Practical implications

– The study discusses the aspect of gender inclusivity in the IT sector as well as the impact of higher skill on gender. The paper proposes some policy initiatives which can increase the number of female employees in the IT sector.

Originality/value

– The study fulfills the need to know about the gender inclusivity aspect of the IT sector in India.
The use of the balanced scorecard to measure knowledge work
Authors: Wake Nicholas John
Published: April 2015

Purpose

– The purpose of this paper is to question whether the balanced scorecard provides an appropriate control mechanism for management control of knowledge workers.

Design/methodology/approach

– A case study approach is taken to explore the way in which management control of employees engaged in research and development is undertaken.

Findings

– The key finding of this work is that the balanced scorecard is not in itself a useful approach to management control of knowledge workers but provides an important mechanism for ensuring that there is alignment between the strategic objectives of an organisation and the work being undertaken.

Research limitations/implications

– The inductive approach taken in a single-company case study has provided a rich data set for exploratory research, however, this research design limits the generalisability of the findings.

Practical implications

– The work provides insights into how the balanced scorecard can be used in knowledge-worker environments.

Originality/value

– The balanced scorecard is often reported as a tool that allows organisations to cascade strategic priorities down to the level of the individual though the use of measures. This research provides an alternative explanation of how the balanced scorecard can support knowledge worker control.
Enterprise resource planning and efficiency
Authors: Park Jonghyun , Park Jin
Published: April 2015

Purpose

– The purpose of this paper is to investigate the efficiency of Korean insurers that have adopted enterprise resource planning (ERP) system to improve their efficiency.

Design/methodology/approach

– The study uses Data Envelopment Analysis (DEA) with several inputs and outputs to measure both technical and scale efficiency. With the efficiency measures and using the ordinary least square with the hetereoscedacity consistent standard errors, the study further investigates the factors affecting efficiency, and the association between ERP and efficiency.

Findings

– This study finds a strong positive association between ERP implementation and the insurers’ efficiency and profitability. However, firms may experience a decrease in efficiency and profitability during the first and second year after ERP implementation.

Research limitations/implications

– Although the findings of this study are consistent with extant studies, the study’s findings may lack generalizability because the samples are limited small Korean Property/Casualty (P/C) insurers.

Originality/value

– This study investigates the impact of ERP implementation on P/C insurers in an emerging market.
Finding “good enough” metrics for the UK’s research excellence framework
Authors: Stuart David
Published: April 2015

Purpose

– The purpose of this paper is to encourage discussion about the potential role of metrics in research assessment.

Design/methodology/approach

– The paper considers the results of the UK’s 2014 Research Excellence Framework, and the potential of metrics to reduce the size of future exercises.

Findings

– The paper suggests that a battery of non-robust metrics selected by the higher education institutions could support a greatly reduced peer-reviewed exercise.

Practical implications

– Policy makers should reconsider the role of metrics in research assessment.

Originality/value

– The paper provides an alternative vision of the role of metrics in research assessment, and will be of interest to policy makers, bibliometricians, and anyone interested in HEI research assessment.
Prevalence of POE in UK higher education institutions
Authors: Riley Mike , Cotgrave Alison , Kokkarinen Noora
Published: April 2015

Purpose

– The purpose of this paper is to identify the extent to which Post-occupancy evaluation (POE) is understood and applied within higher education institutions across the UK and identify users’ perceptions of its efficacy.

Design/methodology/approach

– A mixed methodology was applied to this research. Part one consisted of an online survey intended to generate an overview of the extent of POE use across the sector. The second phase, intended to develop greater insight and understanding of users’ perceptions of POE, relied upon in-depth interviews with a smaller sample drawn those who had completed the survey in part one.

Findings

– Differing models of POE are used within higher education institutions with varying degrees of complexity. Models exist that are based on standard structures and templates, whilst entirely bespoke options have been developed by some institutions. The work found that there is a clear preference for applying bespoke methods rather than standardised ones.

Research limitations/implications

– The research is based on a sample of Directors of Estates (DOEs) from UK Universities. The conclusions relate specifically to that sector and context. The extent for broader generalisation is limited by the research sample.

Practical implications

– The work shows that POE is understood to have differing purpose and effectiveness in individual Universities. As a result there has been a proliferation in the number of models developed and applied. This leads to the conclusion that more coherent and consistent understanding should be promoted within the sector.

Social implications

– The work has implications for the effective management of university buildings to support user satisfaction.

Originality/value

– This paper indicates that there is prevalence of applying POE processes in higher education institutions and that specific models have been developed for the sector. However, the extent to which the process is valued and understood is highly variable.