bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of suction/blowing on the finite amplitude disturbances having non-stationary modes of a compressible boundary layer flow
Authors: Turkyilmazoglu M.
Published: April 2015

In this paper, a weakly non-linear stability analysis is pursued to explore the effects of suction and blowing on a compressible mode of instability of the three-dimensional boundary layer flow induced by a rotating disk. The main thrust of the research is to extend the stationary work of Seddougui and Bassom (1996) to cover for the non-stationary mode so that it is targeted to determine whether the major role in finite amplitude destabilization of the boundary layer is played by the stationary mode of Seddougui and Bassom (1996) or the non-stationary mode as calculated from the present study. Within this perspective, the basic compressible flow obtained in the large Reynolds number limit, together with a suction parameter entering into the wall with normal velocity at the wall, is perturbed by disturbances which are constituted as the non-linear interaction of fundamental modes and harmonics. The effects of non-linearity are then explored by deriving a finite amplitude equation governing the evolution of the non-linear lower branch modes and also allowing the finite amplitude growth of a disturbance close to the neutral location determined from a prior stability analysis. Although the form of the amplitude equation is not at all surprising (given a similar result for the stationary vortices in Seddougui and Bassom (1996)), the dependence of the coefficients of the Landau-type modulated vortex amplitude equation on the frequency parameter is established here. A close examination of the coefficients of this evolution equation indicates strongly that the non-linearity has a destabilizing effect for both suction and blowing through the surface of the disk, the effect of which is much more stronger for a suction. Also the impact of non-linearity is higher for the non-stationary compressible modes than for the stationary waves of Seddougui (1990) and Seddougui and Bassom (1996). Moreover, in the case of suction, there occurs a regime of non-stationary modes that cover not only the positive frequency waves, but also waves having negative frequencies, and these modes are always unstable no matter whether the wall is insulated or isothermal. The solution of the asymptotic amplitude equation further demonstrates that as the local Mach number increases, compressibility has the influence of stabilization by requiring smaller initial amplitude of the disturbance for the laminar rotating disk boundary layer flow to become unstable whenever fluid injection is applied. Unlike this, suction makes the underlying flow more convectively unstable as far as the compressibility is concerned, particulary for the modes generated as a consequence of an isothermal wall. Both for the suction and injection cases, disturbances having positive frequency are always shown to cause an instantaneous non-linear amplification prior to the negative frequency waves.
Stability of fronts for a regularization of the Burgers equation
Authors: Bhat H. , Fetecau R.
Published: April 2015

We consider the stability of traveling waves for the Leray-type regularization of the Burgers equation that was recently introduced and analyzed by the authors in Bhat and Fetecau (2006). These traveling waves consist of “fronts,” which are monotonic profiles that connect a left state to a right state. The front stability results show that the regularized equation mirrors the physics of rarefaction and shock waves in the Burgers equation. Regarded from this perspective, this work provides additional evidence for the validity of the Leray-type regularization technique applied to the Burgers equation.
Itô and Stratonovich stochastic partial differential equations: Transition from microscopic to macroscopic equations
Authors: Kotelenez Peter
Published: April 2015

We review the derivation of stochastic ordinary and quasi-linear stochastic partial differential equations (SODE’s and SPDE’s) from systems of microscopic deterministic equations in space dimension

d
≥
2

d\geq 2

as well as the macroscopic limits of the SPDE’s. The macroscopic limits are quasi-linear (deterministic) PDE’s. Both noncoercive and coercive SPDE’s, driven by Itô differentials with respect to correlated Brownian motions, are considered. For the solutions of semi-linear noncoercive SPDE’s with smooth and homogeneous diffusion kernels we show that these solutions can be obtained as solutions of first-order SPDE’s, driven by Stratonovich differentials and their macroscopic limit, and are solutions of a class of semi-linear second-order parabolic PDE’s. Further, the space-time covariance structure of correlated Brownian motions is described and for space dimension

d
≥
2

d\geq 2

the long-time behavior of the separation of two uncorrelated Brownian motions is shown to be similar to the independent case.
On constructive complex analysis in finance: Explicit formulas for Asian options
Authors: Schröder Michael
Published: April 2015

This paper develops a two-stage approach to the explicit valuation of Asian options which stresses the rôle of complex analytic techniques in general, and special functions in particular. First, integral representations for their Black-Scholes values in terms of Hermite functions are obtained; this is based on a Laplace transform arising in the work of Yor, and proceeds by analytical inversion. Explicit formulas for these integrals are then derived as a second step; this is done by combining series and asymptotic expansions which have as terms at worst special functions such as the error integral. Numerical examples then illustrate how the results enable a benchmark valuation of these options.
The Helmholtz equation in the exterior of slits in a plane with different impedance boundary conditions on opposite sides of the slits
Authors: Krutitskii P.
Published: April 2015

The boundary value problem for the Helmholtz equation is studied outside slits in a plane. The impedance boundary conditions are specified on the slits. In general, the impedance conditions may be different at different sides of each slit. In a particular case, the impedance conditions may be the same on the sides of each slit. It is proved that the classical solution to the problem exists, and it is unique. The integral representation for a solution to the problem is obtained in the form of potentials, the densities in which are uniquely determined from the uniquely solvable system of the Fredholm integral equations of the second kind and index zero.
Overlapping domain problems in the crack theory with possible contact between crack faces
Authors: Khludnev Alexander , Tani Atusi
Published: April 2015

The paper is concerned with the analysis of a new class of overlapping domain problems for elastic bodies having cracks. Inequality type boundary conditions are imposed on the crack faces. We prove an existence of invariant integrals and analyze the asymptotic behavior of the solution. It is shown that the limit problem describes an equilibrium state for the elastic body with a thin inclusion.
Turbulent rivers
Authors: Birnir Björn
Published: April 2015

The existence of solutions describing the turbulent flow in rivers is proven. The existence of an associated invariant measure describing the statistical properties of this one-dimensional turbulence is established. The turbulent solutions are not smooth but Hölder continuous with exponent

3

/

4

3/4

. The scaling of the solutions’ second structure (or width) function gives rise to Hack’s law (1957), stating that the length of the main river, in mature river basins, scales with the area of the basin

l
∼

A

h

l \sim A^{h}

,

h
=
0.568

h = 0.568

being Hack’s exponent.
Some remarks on the numerical approximation of stochastic differential equations
Authors: Ewald Brian , Témam Roger
Published: April 2015

The aim of this article is to discuss the convergence of some numerical stochastic schemes in geophysical fluid dynamics (GFD) and to make some remarks on the numerical analysis of stochastic differential equations (SDEs).
Thermal grooving by surface diffusion: Mullins revisited and extended to multiple grooves
Authors: Martin P.
Published: April 2015

We extend the original Mullins theory of surface grooving due to a single interface to multiple interacting grooves formed due to closely spaced flat interfaces. First, we show that Mullins’ analysis for one groove can be simplified by using Fourier cosine transforms instead of Laplace transforms. Second, we solve the corresponding problem for an infinite periodic row of grooves. For both of these problems, symmetry considerations ensure that the interface conditions reduce to boundary conditions. Third, we solve the problem for two interacting grooves. Continuity requirements at the groove roots require sliding at the interfaces or tilting of the groove roots. We adopt the latter model. We find that the groove roots tilt until the surface curvature of the semi-infinite profiles is eliminated.
Fractional radial diffusion in an infinite medium with a cylindrical cavity
Authors: Povstenko Y.
Published: April 2015

The time-fractional diffusion equation is employed to study the radial diffusion in an unbounded body containing a cylindrical cavity. The Caputo fractional derivative is used. The solution is obtained by application of Laplace and Weber integral transforms. Several examples of problems with Dirichlet and Neumann boundary conditions are presented. Numerical results are illustrated graphically.
Regularity conditions for the 3D Navier-Stokes equations
Authors: Fan Jishan , Gao Hongjun
Published: April 2015

We obtain logarithmic improvements for conditions of regularity in the 3D Navier-Stokes equations.
Nonlinear interfacial waves in streaming flows
Authors: Zakaria Kadry
Published: April 2015

The nonlinear interfacial waves between viscous immiscible liquids have been analyzed, using the concepts of viscous potential flow and Kelvin-Helmholtz instability. The method of multiple scales is used for determining the evolution equations that are near and on the marginal state of the linear theory. We use the modulation concept in solving these equations to determine the stability criteria. Different numerical examples are considered that show the system is at greater risk of instability when the velocity of the stream is larger, whereas the effects of viscosity can be stabilizing or destabilizing.
On existence of a classical solution and nonexistence of a weak solution to the Dirichlet problem for the Laplacian with discontinuous boundary data
Authors: Krutitskii P.
Published: April 2015

The Dirichlet problem for the Laplacian in a planar multiply connected interior domain bounded by smooth closed curves is considered in the case when the boundary data is piecewise continuous; i.e., it may have jumps in certain points of the boundary. It is assumed that the solution to the problem may not be continuous at the same points. The well-posed formulation of the problem is given, theorems on existence and uniqueness of a classical solution are proved, and the integral representation for a classical solution is obtained. The problem is reduced to a uniquely solvable Fredholm integral equation of the second kind and of index zero. It is shown that a weak solution to the problem does not exist typically, though the classical solution exists.
Electro-magneto-encephalography and fundamental solutions
Authors: Dassios G. , Fokas A.
Published: April 2015

Electroencephalography (EEG) and Magnetoencephalography (MEG) are two important methods for the functional imaging of the brain. For the case of the spherical homogeneous model, we elucidate the mathematical relations of these two methods. In particular, we derive and analyse three different representations for the electric and magnetic potentials, as well as the corresponding electric and magnetic induction fields, namely: integral representations involving the Green and the Neumann kernels, representations in terms of eigenfunction expansions, and closed form expressions. We show that the parts of the EEG and MEG fields in the interior of the brain that are due to the induction current are related via Kelvin’s inversion transformation. We also derive closed form expressions for the interior and exterior vector potentials of the corresponding magnetic induction fields.
Exponential and polynomial decay for first order linear Volterra evolution equations
Authors: Mainini Edoardo , Mola Gianluca
Published: April 2015

We consider, in an abstract setting, an instance of the Coleman-Gurtin model for heat conduction with memory, that is, the Volterra integro-differential equation
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="partial-differential Subscript t Baseline u left-parenthesis t right-parenthesis minus beta normal upper Delta u left-parenthesis t right-parenthesis minus integral Subscript 0 Superscript t Baseline k left-parenthesis s right-parenthesis normal upper Delta u left-parenthesis t minus s right-parenthesis d s equals 0 period">

∂
t

u
(
t
)
−
β
Δ
u
(
t
)
−

∫

0

t

k
(
s
)
Δ
u
(
t
−
s
)
d
s
=
0.

\partial _t u(t) - \beta \Delta u(t) - \int _{0}^{t}k(s)\Delta u(t-s)ds = 0.

\]
We establish new results for the exponential and polynomial decay of solutions, by means of conditions on the convolution kernel which are weaker than the classical differential inequalities.
Orbital stability of standing wave solution for a quasilinear Schrödinger equation
Authors: Guo Boling , Chen Jianqing
Published: April 2015

Via minimization arguments and the Concentration Compactness Principle, we prove the orbital stability of standing wave solutions for a class of quasilinear Schrödinger equation arising from physics.
Global solutions for coupled Kuramoto-Sivashinsky-KdV system
Authors: Cai Maomao , Li Dening
Published: April 2015

We study the global smooth solution for the coupled Kuramoto-Sivanshinsky-KdV system in two-dimensional space. The model is proposed to describe the surface waves on multi-layered liquid films. The global solution is obtained for general initial data, using an a priori estimate for the nonlinear system, and the smoothness of such solution is established in

t
>
0

t >0

.
On spatial behavior in linear viscoelasticity
Authors: Galeş Cătălin , Chiriţă Stan
Published: April 2015

Within the framework of linear viscoelasticity this paper deals with the study of spatial behavior of solutions describing harmonic vibrations in a right cylinder of finite extent. Some exponential decay estimates of Saint–Venant type, in terms of the distance from the excited end of the cylinder are obtained from a first-order differential inequality concerning an appropriate measure associated with the amplitude of the steady-state vibration. The dissipative mechanism guarantees the validity of the result for every value of the frequency of vibration and for the class of viscoelastic materials compatible with thermodynamics whose relaxation tensor is supposed to be symmetric and sufficiently regular. The case of a semi-infinite cylinder is also studied, and some alternatives of Phragmén–Lindelöf type are established.
A nonlocal quenching problem arising in a micro-electro mechanical system
Authors: Guo Jong-Shenq , Hu Bei , Wang Chi-Jen
Published: April 2015

In this paper, we study a nonlocal parabolic problem arising in the study of a micro-electro mechanical system. The nonlocal nonlinearity involved is related to an integral over the spatial domain. We first give the structure of stationary solutions. Then we derive the convergence of a global (in time) solution to the maximal solution as the time tends to infinity. Finally, we provide some quenching criteria.
Mixed type equations in gas dynamics
Authors: Chen Shuxing
Published: April 2015

The paper is mainly concerned with mixed type partial differential equations and their connections with transonic flow. Some typical problems in gas dynamics related to the mixed type equations are presented and analyzed. In the meantime, the crucial points on the study of these problems, including some recent developments and new approaches, are introduced.
Low-frequency dipolar excitation of a perfect ellipsoidal conductor
Authors: Perrusson Gaële , Vafeas Panayiotis , Lesselier Dominique
Published: April 2015

This paper deals with the scattering by a perfectly conductive ellipsoid under magnetic dipolar excitation at low frequency. The source and the ellipsoid are embedded in an infinite homogeneous conducting ground. The main idea is to obtain an analytical solution of this scattering problem in order to have a fast numerical estimation of the scattered field that can be useful for real data inversion. Maxwell equations and boundary conditions, describing the problem, are firstly expanded using low-frequency expansion of the fields up to order three. It will be shown that fields have to be found incrementally. The static one (term of order zero) satisfies the Laplace equation. The next non-zero term (term of order two) is more complicated and satisfies the Poisson equation. The order-three term is independent of the previous ones and is described by the Laplace equation. They constitute three different scattering problems that are solved using the separated variables method in the ellipsoidal coordinate system. Solutions are written as expansions on the few analytically known scalar ellipsoidal harmonics. Details are given to explain how those solutions are achieved with an example of numerical results.
On diffusive slowdown in three-layer Hele-Shaw flows
Authors: Daripa Prabir , Pasa Gelu
Published: April 2015

In a recently published article of Daripa and Pasa [Transp. Porous Media (2007) 70:11-23], the stabilizing effect of diffusion in three-layer Hele-Shaw flows was proved using an exact analysis of normal modes. In particular, this was established from an upper bound on the growth rate of instabilities which was derived from analyzing stability equations. However, the method used there is not constructive in the sense that the upper bound derived from actual numerical discretization of the problem could be significantly different from the exact one reported depending on the scheme used. In this paper, a numerical approach to solve the stability equations using a finite difference scheme is presented and analyzed. An upper bound on the growth rate is derived from numerical analysis of the discrete system which also shows the diffusive slowdown of instabilities. Upper bounds obtained by this numerical approach and by the analytical approach are compared. The present approach is constructive and directly leads to the implementation of the numerical approach to obtain approximate solutions in the presence of diffusion. The contributions of the paper are the novelty of the approach and a bound on the growth rates that does not depend on the solution itself.
Initial boundary value problem for semilinear hyperbolic equations and parabolic equations with critical initial data
Authors: Runzhang Xu
Published: April 2015

We study the initial boundary value problem of semilinear hyperbolic equations

u

t
t

−
Δ
u
=
f
(
u
)

u_{tt}-\Delta u=f(u)

and semilinear parabolic equations

u

t

−
Δ
u
=
f
(
u
)

u_{t}-\Delta u=f(u)

with critical initial data

E
(
0
)
=
d

E(0)=d

(or

J
(

u
0

)
=
d

J(u_0)=d

),

I
(

u
0

)
>
0

I(u_0)>0

, and prove that there exist non-global solutions under classical conditions on

f
f

.
Transient temperature response of spherical bodies
Authors: Choudhury Bejoy
Published: April 2015

Fundamental temperature solutions in closed form of composite spherical bodies are given for mixed and time-dependent boundary conditions. Solid and hollow spherical bodies are included as further examples. The solution requires calculating the roots of certain transcendental equations. A method is developed to find the roots rapidly. As a practical application, the two-layer composite solution is used to determine the available fuel mass of an orbiting spacecraft.
Transient behavior of solutions to a class of nonlinear boundary value problems
Authors: Bryan Kurt , Vogelius Michael
Published: April 2015

In this paper we consider the asymptotic behavior in time of solutions to the heat equation with nonlinear Neumann boundary conditions of the form

∂
u

/

∂

n

=
F
(
u
)

\partial u/\partial \mathbf {n}=F(u)

, where

F
F

is a function that grows superlinearly. Solutions frequently exist for only a finite time before “blowing up.” In particular, it is well known that solutions with initial data of one sign must blow up in finite time, but the situation for sign-changing initial data is less well understood. We examine in detail conditions under which solutions with sign-changing initial data (and certain symmetries) must blow up, and also conditions under which solutions actually decay to zero. We carry out this analysis in one space dimension for a rather general

F
F

, while in two space dimensions we confine our analysis to the unit disk and

F
F

of a special form.
Stability criteria of 3D inviscid shears
Authors: Li Y.
Published: April 2015

Recent numerical studies in the area of transition to turbulence discovered that the classical plane Couette flow, plane Poiseuille flow, and pipe Poiseuille flow share some universal 3D steady coherent structure in the form of a “streak-roll-critical layer”. As the Reynolds number approaches infinity, the steady coherent structure approaches a 3D limiting shear of the form (

U
(
y
,
z
)
,
0
,
0

U(y,z), 0, 0

) in velocity variables. All such 3D shears are steady states of the 3D Euler equations. This raises the importance of investigating the stability of such inviscid 3D shears in contrast to the classical Rayleigh theory of inviscid 2D shears. Several general criteria of stability for such inviscid 3D shears are derived. In the Appendix, an argument is given to show that a 2D limiting shear can only be the classical laminar shear.
On the Cauchy problem for the Degasperis-Procesi equation
Authors: Gui Guilong , Liu Yue
Published: April 2015

We establish here the local well-posedness for the Degasperis-Procesi equation in the Besov spaces. We also determine some blow-up criteria of the strong solutions and investigate the nonexistence of smooth solitary-wave solutions.
Modeling consciousness as an adaptive phenomenon
Authors: Miranker Willard
Published: April 2015

We start at the level of a bacterium where an observer feature associated with foraging measurements motivates introduction of a notion of awareness (a proto-consciousness) as a primitive, a dualist construct. The relative simplicity of Darwinian concepts at the level of a bacterial colony then leads to development of an analytic theory of perceptual consciousness that includes colonial notions of qualia. Results of simulations that verify the colonial principles developed are given. We extend this approach, first to a neuron and then to a neuronal assembly, each extension accompanied by a derived consciousness construct. For each construct (dualist or derived), a mathematical model in the form of a measurable quantity called a token is developed. The pairs, token and construct, permit the design of experiments that would validate the theory. Applications of the theory are developed, each based upon the analytic model (the tokens) and each explaining a familiar aspect of human consciousness in mathematical terminology.
Global regularity for a coupled Cahn-Hilliard-Boussinesq system on bounded domains
Authors: Zhao Kun
Published: April 2015

We study an initial-boundary value problem (IBVP) for a coupling of the Cahn-Hilliard equation with the 2D inviscid heat-conductive Boussinesq equations. For large initial data with finite energy, we prove global existence and uniqueness of classical solutions to the IBVP, together with some uniform-in-time and decay estimates of the solution.
Global attractors for the suspension bridge equations with nonlinear damping
Authors: Park Jong-Yeoul , Kang Jum-Ran
Published: April 2015

In this paper, we prove the existence of a global attractor for the suspension bridge equations with nonlinear damping.
The Arp2/3 complex has essential roles in vesicle trafficking and transcytosis in the mammalian small intestine
Authors: Zhou Kang , Sumigray Kaelyn D. , Lechler Terry
Published: April 2015

The Arp2/3 complex is the only known nucleator of branched F-actin filaments. Work in cultured cells has established a wide array of functions for this complex in controlling cell migration, shape, and adhesion. However, loss of Arp2/3 complex function in tissues has yielded cell type–specific phenotypes. Here we report essential functions of the Arp2/3 complex in the intestinal epithelium. The Arp2/3 complex was dispensable for intestinal development, generation of cortical F-actin, and cell polarity. However, it played essential roles in vesicle trafficking. We found that in the absence of ArpC3, enterocytes had defects in the organization of the endolysosomal system. These defects were physiologically relevant, as transcytosis of IgG was disrupted, lipid absorption was perturbed, and neonatal mice died within days of birth. These data highlight the important roles of the Arp2/3 complex in vesicle trafficking in enterocytes and suggest that defects in cytoplasmic F-actin assembly by the Arp2/3 complex, rather than cortical pools, underlie many of the phenotypes seen in the mutant small intestine.
Diagnosis of paired age agreement: a simulation of accuracy and precision effects
Authors: McBride Richard S.
Published: April 2015

In a typical age and growth study, multiple estimates of individual fish age are generated: by readers, methods, etc. These samples of paired data are evaluated with three complementary approaches: (i) tabulate or graph the data to illustrate patterns, (ii) calculate indices of precision to evaluate repeatability, and more recently, (iii) use tests of symmetry to evaluate bias. Herein, I simulated age data to evaluate the diagnostic power of these different approaches in terms of four types of accuracy: (i) no bias between known and estimated age, (ii) bias by adding 1 year to the estimated age, (iii) bias by subtracting 10% from the estimated age, and (iv) both biases together. Precision of estimated ages (standard deviation = 5, 10, and 15% of known age) was varied for each type of bias. Age-bias plots had difficulty detecting bias in ages classes with few (e.g. ≤5) individuals sampled. A Bland–Altman-bubble plot is introduced as an alternative to age-bias plots. In these simulations, the various indices of precision were either not diagnostic (i.e. per cent agreement) or redundant (average per cent error could be predicted from Chang's coefficient of variation). Evans and Hoenig's test and Bowker's test of symmetry performed well in most simulations, but each has specific weaknesses. Bowker's test was superior by having marginally fewer type I error rates; however, it had much worse type II error rates. McNemar's test offered no additional interpretative power in these simulations. All tests of symmetry had difficulty diagnosing bias when precision was low. These simulated results support continued use of all three approaches because they are complementary. Additional simulations would be helpful to confirm that these guidelines are relevant in other representative cases.
Two Distinct Hepatitis C Virus Genotype 1a Clades Have Different Geographical Distribution and Association With Natural Resistance to NS3 Protease Inhibitors
Authors: De Luca Andrea , Di Giambenedetto Simona , Lo Presti Alessandra , Sierra Saleta , Prosperi Mattia , Cella Eleonora , Giovanetti Marta , Torti Carlo , Caudai Cinzia , Vicenti Ilaria , Saladini Francesco , Almi Paolo , Grima Pierfrancesco , Blanc Pierluigi , Fabbiani Massimiliano , Rossetti Barbara , Gagliardini Roberta , Kaiser Rolf , Ciccozzi Massimo , Zazzi Maurizio
Published: April 2015

Background.  Hepatitis C virus (HCV) genotype 1 is the most prevalent worldwide. Subtype 1a, compared with 1b, shows lower response rates and higher propensity to select for drug resistance to NS3 and selected NS5A and nonnucleoside NS5B inhibitors. Two distinct clades of subtype 1a have been described.

Methods.  Using Bayesian methodology, we performed a time-scaled phylogeny reconstruction of clade separation and characterized the geographic distribution, phylodynamics, and association with natural resistance variants of NS3 sequences from 362 patients carrying subtype 1a HCV.

Results.  All sequences segregated in 2 clearly distinct clades. Clade I showed an earlier origin from the common ancestor compared with clade II. Clade I virus was more prevalent in non-European countries, represented mostly by United States, compared with European (75.7% vs 49.3%; P < .001). The prevalence of the natural NS3 variant Q80K, associated with resistance to the macrocyclic protease inhibitor simeprevir, was detected in 51.6% of clade I and 0% of clade II (P < .001); clade I showed a lower genetic barrier for Q80K, whereas no sign of selective pressure at any protease inhibitor resistance-associated codon was detected.

Conclusions.  Hepatitis C virus subtype 1a clades have a clearly different distribution in Europe and the United States, and the natural resistance mutation Q80K is exclusively associated with clade I.
Suzaku observation of X-ray variability in soft state LMC X-1
Authors: Koyama Shu , Yamada Shin'ya , Kubota Aya , Tashiro Makoto S. , Terada Yukikatsu , Makishima Kazuo
Published: April 2015

This paper reports the results of Suzaku observation of the spectral variation of the black hole binary LMC X-1 in the soft state. The observation was carried out in 2009 from July 21 to 24. the obtained net count rate was ∼ 30 counts s−1 in the 0.5–50 keV band with ∼ 10% peak-to-peak flux variation. The time-averaged X-ray spectrum cannot be described by a multi-color disk and single Compton component with its reflection, but requires additional Comptonized emissions. This double Compton component model allows a slightly larger inner radius of the multi-color disk, implying a lower spin parameter. Significant spectral evolution was observed above 8 keV along with a flux decrease on a timescale of ∼ 104–105 s. By spectral fitting, we show that this behavior is well explained by changes in the hard Comptonized emission component in contrast to the maintained disk and soft Comptonized emission.
‘Neanderthal bone flutes’: simply products of Ice Age spotted hyena scavenging activities on cave bear cubs in European cave bear dens
Authors: Diedrich Cajus G.
Published: April 2015

Punctured extinct cave bear femora were misidentified in southeastern Europe (Hungary/Slovenia) as ‘Palaeolithic bone flutes’ and the ‘oldest Neanderthal instruments’. These are not instruments, nor human made, but products of the most important cave bear scavengers of Europe, hyenas. Late Middle to Late Pleistocene (Mousterian to Gravettian) Ice Age spotted hyenas of Europe occupied mainly cave entrances as dens (communal/cub raising den types), but went deeper for scavenging into cave bear dens, or used in a few cases branches/diagonal shafts (i.e. prey storage den type). In most of those dens, about 20% of adult to 80% of bear cub remains have large carnivore damage. Hyenas left bones in repeating similar tooth mark and crush damage stages, demonstrating a butchering/bone cracking strategy. The femora of subadult cave bears are intermediate in damage patterns, compared to the adult ones, which were fully crushed to pieces. Hyenas produced round–oval puncture marks in cub femora only by the bone-crushing premolar teeth of both upper and lower jaw. The punctures/tooth impact marks are often present on both sides of the shaft of cave bear cub femora and are simply a result of non-breakage of the slightly calcified shaft compacta. All stages of femur puncturing to crushing are demonstrated herein, especially on a large cave bear population from a German cave bear den.
Atomic scale modelling of hexagonal structured metallic fission product alloys
Authors: Middleburgh S. C. , King D. M. , Lumpkin G. R.
Published: April 2015

Noble metal particles in the Mo-Pd-Rh-Ru-Tc system have been simulated on the atomic scale using density functional theory techniques for the first time. The composition and behaviour of the epsilon phases are consistent with high-entropy alloys (or multi-principal component alloys)—making the epsilon phase the only hexagonally close packed high-entropy alloy currently described. Configurational entropy effects were considered to predict the stability of the alloys with increasing temperatures. The variation of Mo content was modelled to understand the change in alloy structure and behaviour with fuel burnup (Mo molar content decreases in these alloys as burnup increases). The predicted structures compare extremely well with experimentally ascertained values. Vacancy formation energies and the behaviour of extrinsic defects (including iodine and xenon) in the epsilon phase were also investigated to further understand the impact that the metallic precipitates have on fuel performance.
Receiving of emotional signal of pain from conspecifics in laboratory rats
Authors: Nakashima Satoshi F. , Ukezono Masatoshi , Nishida Hiroshi , Sudo Ryunosuke , Takano Yuji
Published: April 2015

Though recent studies have shown that rodents express emotions with their face, whether emotional expression in rodents has a communicative function between conspecifics is still unclear. Here, we demonstrate the ability of visual recognition of emotional expressions in laboratory rats. We found that Long-Evans rats avoid images of pain expressions of conspecifics but not those of neutral expressions. The results indicate that rats use visual emotional signals from conspecifics to adjust their behaviour in an environment to avoid a potentially dangerous place. Therefore, emotional expression in rodents, rather than just a mere ‘expression’ of emotional states, might have a communicative function.
Bacillus lycopersici sp. nov., isolated from a tomato plant (Solanum lycopersicum L.)
Authors: Lin Shih-Yao , Hameed Asif , Liu You-Cheng , Wen Cheng-Zhe , Lai Wei-An , Hsu Yi-Han , Young Chiu-Chung
Published: April 2015

A Gram-stain-positive, rod-shaped, endospore-forming bacterium (designated strain CC-Bw-5T) was isolated from chopped tomato stems. The isolate grew at 20–40 °C, pH 6.0–8.0 and tolerated 6  % (w/v) NaCl. The most closely related strains in terms of 16S rRNA gene sequence similarity wereBacillus isabeliae(95.3  %) andBacillus oleronius(95.3  %). The G+C content of the genomic DNA was 37.2 ± 3.6 mol%. Strain CC-Bw-5Twas determined to possess C16 : 0, iso-C14 : 0, iso-C15 : 0, anteiso-C15 : 0and iso-C16 : 0as predominant fatty acids. The polar lipid profile consisted of predominant amounts of diphosphatidylglycerol, and moderate-to-trace amounts of phosphatidylethanolamine, phosphatidylglycerol, two unidentified glycolipids, an unidentified phospholipid and an unidentified phosphoglycolipid. The cell-wall peptidoglycan containedmeso-diaminopimelic acid; menaquinone (MK-7) was the predominant respiratory quinone. According to distinct phylogenetic, phenotypic and chemotaxonomic features, strain CC-Bw-5Tis proposed to represent a novel species within the genusBacillusfor which the nameBacillus lycopersicisp. nov. is proposed. The type strain is CC-Bw-5T( = BCRC 80623T = JCM 19140T).
Live attenuated simian immunodeficiency virus vaccination confers superinfection resistance against macrophage-tropic and neurovirulent wild-type SIV challenge
Authors: Berry Neil , Ham Claire , Alden Jack , Clarke Sean , Stebbings Richard , Stott Jim , Ferguson Deborah , Almond Neil
Published: April 2015

Vaccination with live attenuated simian immunodeficiency virus (SIV) in non-human primate species provides a means of characterizing the protective processes of retroviral superinfection and may lead to novel advances of human immunodeficiency virus (HIV)/AIDS vaccine design. The minimally attenuated SIVmacC8 vaccine has been demonstrated to elicit early potent protection against pathogenic rechallenge with genetically diverse viral isolates in cynomolgus macaques (Macaca fascicularis). In this study, we have characterized further the biological breadth of this vaccine protection by assessing the ability of both the nef-disrupted SIVmacC8 and its nef-intact counterpart SIVmacJ5 viruses to prevent superinfection with the macrophage/neurotropic SIVmac239/17E-Fr (SIVmac17E-Fr) isolate. Inoculation with either SIVmacC8 or SIVmacJ5 and subsequent detailed characterization of the viral replication kinetics revealed a wide range of virus–host outcomes. Both nef-disrupted and nef-intact immunizing viruses were able to prevent establishment of SIVmac17E-Fr in peripheral blood and secondary lymphoid tissues. Differences in virus kinetics, indicative of an active process, identified uncontrolled replication in one macaque which although able to prevent SIVmac17E-Fr superinfection led to extensive neuropathological complications. The ability to prevent a biologically heterologous, CD4-independent/CCR5+ viral isolate and the macrophage-tropic SIVmac316 strain from establishing infection supports the hypothesis that direct target cell blocking is unlikely to be a central feature of live lentivirus vaccination. These data provide further evidence to demonstrate that inoculation of a live retroviral vaccine can deliver broad spectrum protection against both macrophage-tropic as well as lymphocytotropic viruses. These data add to our knowledge of live attenuated SIV vaccines but further highlight potential safety concerns of vaccinating with a live retrovirus.
Historic and prehistoric human-driven extinctions have reshaped global mammal diversity patterns
Authors: Faurby Søren , Svenning Jens-Christian
Published: April 2015

Aim: To assess the extent to which humans have reshaped Earth's biodiversity, by estimating natural ranges of all late Quaternary mammalian species, and to compare diversity patterns based on these with diversity patterns based on current distributions. Location: Globally Methods: We estimated species, functional and phylogenetic diversity patterns based on natural ranges of all mammalian species (n=5747 species) as they could have been today in the complete absence of human influence through time. Following this we compared macroecological analyses of current and natural diversity patterns to assess if human-induced range changes bias for evolutionary and ecological analyses based on current diversity patterns. Results: We find that current diversity patterns have been drastically modified by humans, mostly due to global extinctions and regional to local extirpations. Current and natural diversities exhibit marked deviations virtually everywhere outside sub-Saharan Africa. These differences are strongest for terrestrial megafauna, but also important for all mammals combined. The human-induced changes led to biases in estimates of environmental diversity drivers, especially for terrestrial megafauna, but also for all mammals combined. Main conclusions: Our results show that fundamental diversity patterns have been reshaped by human-driven extinctions and extirpations, highlighting humans as a major force in the Earth system. We thereby emphasize that estimating natural distributions and diversities is important to improve our understanding of the evolutionary and ecologically drivers of diversity as well as for providing a benchmark for conservation.
Un–complicating protein complex prediction
Authors: Koutroumpas Konstantinos , Képès François
Published: April 2015

Identification of protein complexes from proteomic experiments is crucial to understand not only their function but also the principles of cellular organization. Advances in experimental techniques have enabled the construction of large–scale protein–protein interaction networks, and computational methods have been developed to analyze high–throughput data. In most cases several parameters are introduced that have to be trained before application. But how do we select the parameter values when there are no training data available? How many data do we need to properly train a method. How is the performance of a method affected when we incorrectly select the parameter values? The above questions, although important to determine the applicability of a method, are most of the time over-looked. We highlight the importance of such an analysis by investigating how limited knowledge, in the form of incomplete training data, affects the performance of parametric protein–complex prediction algorithms. Furthermore, we develop a simple non–parametric method that does not rely on the existence of training data and we compare it with the parametric alternatives. Using datasets from yeast and fly we demonstrate that parametric methods trained with limited data provide sub–optimal predictions, while our non–parametric method performs better or is on par with the parametric alternatives. Overall, our analysis questions, at least for the specific problem, whether parametric methods provide significantly better results than non–parametric ones to justify the additional effort for applying them.
A mathematical framework for statistical decision confidence
Authors: Hangya Balázs , Sanders Joshua I. , Kepecs Adam
Published: April 2015

Decision confidence is a forecast about the probability that a decision will be correct. Confidence can be framed as an objective mathematical quantity the Bayesian posterior probability, providing a formal definition of statistical decision confidence. Here we use this definition as a starting point to develop a normative statistical framework for decision confidence. We analytically prove interrelations between statistical decision confidence and other observable decision measures. Among these is a counterintuitive property of confidence that the lowest average confidence occurs when classifiers err in the presence of the strongest evidence. These results lay the foundations for a mathematically rigorous treatment of decision confidence that can lead to a common framework for understanding confidence across different research domains, from human behavior to neural representations.
On the Optimal Use of Isotherm Models for the Characterization of Biosorption of Lead Onto Algae
Authors: Brouers F. , Al-Musawi Tariq J.
Published: April 2015

In this study the experimental isotherm data of biosorption of Pb(II) onto algae was modeled using several models. These models are: Langmuir, Hill-Sips, Brouers-Sotolongo, Brouers-Gaspard, and Redlich-Peterson models. The coefficients of each model were determined by non-linear fitting using Mathematica9 program. The maximum Pb(II) removal rate increased with the increase of temperature and reached the maximum value (98%) at the temperature of 40 °C. Even if the R2error quantity is not the unique and always the best measure for nonlinear fitting, the Brouers-Sotolongo model gives in all cases the best fit and is definitely the most suitable one to satisfactorily describe bioisorption of Pb(II) on the algal biomass. In addition, this study shows that a complete set of data is necessary to have a good representation of the isotherm.
Trimethylation of Lys36 on H3 restricts gene expression change during aging and impacts life span
Authors: Pu Mintie , Ni Zhuoyu , Wang Minghui , Wang Xiujuan , Wood Jason G. , Helfand Stephen L. , Yu Haiyuan , Lee Siu Sylvia
Published: April 2015

Functional data indicate that specific histone modification enzymes can be key to longevity inCaenorhabditis elegans, but the molecular basis of how chromatin structure modulates longevity is not well understood. In this study, we profiled the genome-wide pattern of trimethylation of Lys36 on histone 3 (H3K36me3) in the somatic cells of young and oldCaenorhabditis elegans.We revealed a new role of H3K36me3 in maintaining gene expression stability through aging with important consequences on longevity. We found that genes with dramatic expression change during aging are marked with low or even undetectable levels of H3K36me3 in their gene bodies irrespective of their corresponding mRNA abundance. Interestingly, 3′ untranslated region (UTR) length strongly correlates with H3K36me3 levels and age-dependent mRNA expression stability. A similar negative correlation between H3K36me3 marking and mRNA expression change during aging was also observed inDrosophila melanogaster, suggesting a conserved mechanism for H3K36me3 in suppressing age-dependent mRNA expression change. Importantly, inactivation of the methyltransferasemet-1resulted in a decrease in global H3K36me3 marks, an increase in mRNA expression change with age, and a shortened life span, suggesting a causative role of the H3K36me3 marking in modulating age-dependent gene expression stability and longevity.
Essential roles for the splicing regulator nSR100/SRRM4 during nervous system development
Authors: Quesnel-Vallières Mathieu , Irimia Manuel , Cordes Sabine P. , Blencowe Benjamin J.
Published: April 2015

Alternative splicing (AS) generates vast transcriptomic complexity in the vertebrate nervous system. However, the extent to whichtrans-acting splicing regulators and their target AS regulatory networks contribute to nervous system development is not well understood. To address these questions, we generated mice lacking the vertebrate- and neural-specific Ser/Arg repeat-related protein of 100 kDa (nSR100/SRRM4). Loss of nSR100 impairs development of the central and peripheral nervous systems in part by disrupting neurite outgrowth, cortical layering in the forebrain, and axon guidance in the corpus callosum. Accompanying these developmental defects are widespread changes in AS that primarily result in shifts to nonneural patterns for different classes of splicing events. The main component of the altered AS program comprises 3- to 27-nucleotide (nt) neural microexons, an emerging class of highly conserved AS events associated with the regulation of protein interaction networks in developing neurons and neurological disorders. Remarkably, inclusion of a 6-nt, nSR100-activated microexon in Unc13b transcripts is sufficient to rescue a neuritogenesis defect in nSR100 mutant primary neurons. These results thus reveal critical in vivo neurodevelopmental functions of nSR100 and further link these functions to a conserved program of neuronal microexon splicing.
miR-182 integrates apoptosis, growth, and differentiation programs in glioblastoma
Authors: Kouri Fotini M. , Hurley Lisa A. , Daniel Weston L. , Day Emily S. , Hua Youjia , Hao Liangliang , Peng Chian-Yu , Merkel Timothy J. , Queisser Markus A. , Ritner Carissa , Zhang Hailei , James C. David , Sznajder Jacob I. , Chin Lynda , Giljohann David A. , Kessler John A. , Peter Marcus E. , Mirkin Chad A. , Stegh Alexander H.
Published: April 2015

Glioblastoma multiforme (GBM) is a lethal, therapy-resistant brain cancer consisting of numerous tumor cell subpopulations, including stem-like glioma-initiating cells (GICs), which contribute to tumor recurrence following initial response to therapy. Here, we identified miR-182 as a regulator of apoptosis, growth, and differentiation programs whose expression level is correlated with GBM patient survival. Repression of Bcl2-like12 (Bcl2L12), c-Met, and hypoxia-inducible factor 2α (HIF2A) is of central importance to miR-182 anti-tumor activity, as it results in enhanced therapy susceptibility, decreased GIC sphere size, expansion, and stemness in vitro. To evaluate the tumor-suppressive function of miR-182 in vivo, we synthesized miR-182-based spherical nucleic acids (182-SNAs); i.e., gold nanoparticles covalently functionalized with mature miR-182 duplexes. Intravenously administered 182-SNAs penetrated the blood–brain/blood–tumor barriers (BBB/BTB) in orthotopic GBM xenografts and selectively disseminated throughout extravascular glioma parenchyma, causing reduced tumor burden and increased animal survival. Our results indicate that harnessing the anti-tumor activities of miR-182 via safe and robust delivery of 182-SNAs represents a novel strategy for therapeutic intervention in GBM.