bluuebunny/crossref_metadata_2025 huggingface dataset:
Design indicators and structure optimisation of switched reluctance machine for electric vehicles
Authors: Cheng He , Chen H. , Yang Zhou
Published: April 2015

Switched reluctance machine (SRM) has the features of high efficiency, high power density and high reliability, which are appropriate for electric vehicles (EVs). First, the design indicators of SRM are proposed according to the requirements of electric drive system and inherent characteristics of SRM. The non‐linear dynamic simulation models are built with finite element analysis, and the optimisation approaches of every indicator are put forward based on the simulation models. Then the structure parameters of SRM are optimised to maximise the developed multi‐objective function and the indicators have different weight factors on the basic of comprehensive requirements of EVs. At last, an optimised SRM prototype is built. The simulation and experimental results have demonstrated the correctness of the design indicators and optimisation methods. Therefore this paper offers a valuable technological improvement for the design of SRM drives for EVs.
Wavelet‐based blind deconvolution of near‐field ultrasound scans
Authors: Taylor Jason R.B. , Mijares Chan Jose J. , Thomas Gabriel
Published: April 2015

A wavelet‐based technique for blind deconvolution and denoising of ultrasound scans is introduced. The target application is near‐field ultrasound imaging for non‐destructive testing. Existing blind deconvolution techniques for ultrasound such as cepstrum‐based methods and the work of Adam and Michailovich – based on discrete wavelet transform (DWT) shrinkage of the log‐spectrum – estimate the pulse by exploiting the pulse log‐spectrum smoothness relative to the material reflectivity function. In the proposed technique, the log‐spectrum is localised with respect to time as the continuous wavelet transform (CWT) log‐scalogram to deal with the non‐stationarity of the near‐field ultrasound signals in both the pulse estimation and deconvolution. The pulse is estimated in the wavelet domain via DWT shrinkage of the log‐scalogram and is deconvolved by wavelet‐domain Wiener filtering. Extensions of the proposed technique include: using separate CWT domains for estimation and deconvolution, as inspired by the WienerChop denoising method; and training the algorithm parameters on a subset of scans.
Specific features of the magnetic properties of RB4 (R = Ce, Sm and Yb) tetraborides. Effects of pressure
Authors: Panfilov A. S. , Grechnev G. E. , Zhuravleva I. P. , Fedorchenko A. V. , Muratov V. B.
Published: April 2015

The temperature dependence and the effect of pressure P up to 2 kbar on the magnetic susceptibility χ of the tetraborides SmB4 and YbB4 was studied. For the compound CeB4, the electronic structure and magnetic susceptibility were calculated from first principles as a function of the atomic volume. The results show that in the studied tetraborides, rare-earth ions (Ce4+, Sm3+ and Yb2.8+) exhibit different valence states, which determines the specific features of their magnetic properties. In particular, the obtained pressure derivatives of susceptibility dlnχ/dP for cerium, samarium and ytterbium tetraborides are −2, −0.6 and +2.7 (in units of Mbar−1), respectively, which are characteristic for the exchange-enhanced itinerant paramagnetism, Van Vleck ionic paramagnetism with a stable f-shell, and the magnetism of rare-earth ions in the intermediate valence state.
Quantum magnetotransport in n-InGaAs/GaAs structures with electron density changes caused by infrared radiation
Authors: Arapov Yu. G. , Gudina S. V. , Neverov V. N. , Podgornykh S. M. , Saveliev A. P. , Yakunin M. V.
Published: April 2015

An experimental study of the longitudinal ρxx(B, T) and Hall ρxy (B, T) magnetoresistance as a function of the n-InGaAs/GaAs nanostructure transverse magnetic field, with single or double tightly-coupled quantum wells, depending on the width of the well, for magnetic field B = 0–12 T and temperature T = 0.05–100 K ranges, before and after low-temperature illumination by infrared radiation. Before illumination, a change in the samples' temperature dependence of zero-field resistivity ρ(T) was detected, from “dielectric” (dρ/dT < 0) to “metallic” (dρ/dT > 0). It is shown that the temperature dependence of resistivity is set by the mobility temperature dependence μ(T), the “dielectric” portion of which is related to the quantum corrections to conductivity in the diffusion and ballistic regimes, whereas the “metallic” portion is associated to the scattering of the carriers by acoustic and optic phonons. A slight change in the magnetic-field dependence of the longitudinal magnetoresistance ρxx(B, T) was observed with temperature, near the induction value corresponding to μB = 1. We also found unusual temperature dependence for conductivity components σxx(B, T) and σxy (B, T), at μB = 1. The σxx(B, T) curve has an observable temperature-independent point, whereas σxy (B, T) strongly depends on T at μB = 1. It is established that this regularity is caused by the nature of the temperature dependence of the charge carrier mobility μ(T), in both the diffusion and ballistic regimes. After IR illumination, positive persistent photoconductivity is observed in all samples, associated with a twofold increase in the charge carrier concentration. Resistivity in a zero-magnetic field ρ(T) for such samples also transitions from “dielectric” to “metallic” conductivity, at temperatures lower than before illumination. It is shown that the particularities of the transport after illumination are related to the manifestation of charge carrier concentration temperature dependence.
Damping constant estimation in magnetoresistive readers
Authors: Stankiewicz Andrzej , Hernandez Stephanie
Published: April 2015

The damping constant is a key design parameter in magnetic reader design. Its value can be derived from bulk or sheet film ferromagnetic resonance (FMR) line width. However, dynamics of nanodevices is usually defined by presence of non-uniform modes. It triggers new damping mechanisms and produces stronger damping than expected from traditional FMR. This work proposes a device-level technique for damping evaluation, based on time-domain analysis of thermally excited stochastic oscillations. The signal is collected using a high bandwidth oscilloscope, by direct probing of a biased reader. Recorded waveforms may contain different noise signals, but free layer FMR is usually a dominating one. The autocorrelation function is a reflection of the damped oscillation curve, averaging out stochastic contributions. The damped oscillator formula is fitted to autocorrelation data, producing resonance frequency and damping constant values. Restricting lag range allows for mitigation of the impact of other phenomena (e.g., reader instability) on the damping constant. For a micromagnetically modeled reader, the technique proves to be much more accurate than the stochastic FMR line width approach. Application to actual reader waveforms yields a damping constant of ∼0.03.
Mid-infrared Otto excitation of transverse electric modes in doped graphene
Authors: Ramos-Mendieta F.
Published: April 2015

We have studied numerically the excitation of surface modes of transverse electric polarization in doped graphene. Using the prism-based Otto configuration, the electromagnetic resonances were found within ultra-tiny angular windows of width of order of Δθi = 10−3 degrees or lower, beyond the critical angle where evanescent fields are already available. We obtained absorption peaks of angular position strongly dependent on the prism-graphene separation d, which is larger than dc, the cutoff prism-graphene separation. We prove numerically that dc depends on the graphene parameters and can be written as dc=α/2, where α(ω) is the decay length of the electromagnetic field of the modes. With doping levels of Fermi energy 0.2 eV ≤ μ ≤ 0.3 eV, we found resonances within the range of 80–145 THz. The numerical calculations show the mayor role played by the graphene losses that, indeed, can obliterate the mode resonance.
Potential around a dust grain in collisional plasma
Authors: Moulick R. , Goswami K. S.
Published: April 2015

The ion neutral collision can lead to interesting phenomena in dust charging, totally different from the expectations based on the traditional orbit motion limited theory. The potential around a dust grain is investigated for the collisional plasma considering the presence of ion neutral collisions. Fluid equations are solved for the one dimensional radial coordinate. It is observed that with the gradual increase in ion neutral collision, the potential structure around the dust grain changes its shape and is different from the usual Debye-Hückel potential. The shift however starts from a certain value of ion neutral collision and the electron-ion density varies accordingly. The potential variation is interesting and reconfirms the fact that there exists a region of attraction for negative charges. The collision modeling is done for the full range of plasma, i.e., considering the bulk and the sheath jointly. The potential variation with collision is also shown explicitly and the variation is found to cope up with the earlier observations.
Investigating temperature degradation in THz quantum cascade lasers by examination of temperature dependence of output power
Authors: Albo Asaf , Hu Qing
Published: April 2015

In this paper, we demonstrate a method to investigate the temperature degradation of THz quantum cascade lasers (QCLs) based on analyzing the dependence of lasing output power on temperature. The output power is suggested to decrease exponentially with some characteristic activation energy indicative of the degradation mechanism. As a proof of concept, Arrhenius plots of power versus temperature are used to extract the activation energy in vertical transition THz QCLs. The extracted energies are consistent with thermally activated longitudinal optical-phonon scattering being the dominant degradation mechanism, as is generally accepted. The extracted activation energy values are shown to be in good agreement with the values predicted from laser spectra.
Sign change in the tunnel magnetoresistance of Fe3O4/MgO/Co-Fe-B magnetic tunnel junctions depending on the annealing temperature and the interface treatment
Authors: Marnitz L. , Rott K. , Niehörster S. , Klewe C. , Meier D. , Fabretti S. , Witziok M. , Krampf A. , Kuschel O. , Schemme T. , Kuepper K. , Wollschläger J. , Thomas A. , Reiss G. , Kuschel T.
Published: April 2015

Magnetite (Fe3O4) is an eligible candidate for magnetic tunnel junctions (MTJs) since it shows a high spin polarization at the Fermi level as well as a high Curie temperature of 585°C. In this study, Fe3O4/MgO/Co-Fe-B MTJs were manufactured. A sign change in the TMR is observed after annealing the MTJs at temperatures between 200°C and 280°C. Our findings suggest an Mg interdiffusion from the MgO barrier into the Fe3O4 as the reason for the change of the TMR. Additionally, different treatments of the magnetite interface (argon bombardment, annealing at 200°C in oxygen atmosphere) during the preparation of the MTJs have been studied regarding their effect on the performance of the MTJs. A maximum TMR of up to -12% could be observed using both argon bombardment and annealing in oxygen atmosphere, despite exposing the magnetite surface to atmospheric conditions before the deposition of the MgO barrier.
Matter-wave metrology meets cavity optics
Authors: Smart Ashley G.
Published: April 2015

Placed between two mirrors, an atom interferometer gains potency and precision.
Exploring the seasonal NMHC distribution in an urban area of the Middle East during ECOCEM campaigns: very high loadings dominated by local emissions and dynamics
Authors: Salameh Thérèse , Sauvage Stéphane , Afif Charbel , Borbon Agnès , Léonardis Thierry , Brioude Jérôme , Waked Antoine , Locoge Nadine
Published: April 2015

Environmental context Non-methane hydrocarbons play an important role in the formation of photochemical oxidants such as ozone. We investigate factors controlling the distribution of non-methane hydrocarbons in an urban area of the Middle East. The study highlights the importance of local emissions and atmospheric dynamics, and the limited effect of photochemistry at the measurement site. Abstract Measurements of over 70 C2-C16 non-methane hydrocarbons (NMHCs) were conducted in suburban Beirut (1.3 million inhabitants) in summer 2011 and winter 2012 during the Emission and Chemistry of Organic Carbon in the East Mediterranean (ECOCEM) field campaign. The levels of NMHCs observed exceeded by a factor of two in total volume the levels found in northern mid-latitude megacities (Paris and Los Angeles), especially for the unburned fossil fuel fraction. Regardless of the season, the major compounds, explaining 50% of the concentrations, were toluene, isopentane, butane, m,p-xylenes, propane and ethylene, emitted by mobile traffic and gasoline evaporation sources. Most NMHCs show a distinct seasonal cycle, with a summer maximum and a winter minimum, unlike seasonal cycles usually observed in the northern mid-latitude urban areas. We show that NMHC distribution is mainly driven by strong local emissions and local atmospheric dynamics, with no clear evidence of photochemical removal in summer or influence from long-range transport.
The association between coral communities and disease assemblages in the Wakatobi Marine National Park, south-eastern Sulawesi, Indonesia
Authors: Haapkylä J. , Melbourne-Thomas J. , Flavell M.
Published: April 2015

The relationship between coral community structure and disease prevalence is poorly understood, particularly in the Coral Triangle. Improved understanding of this relationship will assist in identifying assemblages that might be particularly vulnerable to disease, and in predicting possible future impacts. Here, we report results from the last 2 years (2010 and 2011) of a 4-year coral disease-monitoring program (2005, 2007, 2010, 2011) in the Wakatobi Marine National Park (Indonesia), and evaluate changes in total disease prevalence and coral cover since 2005. A comparison with previously published results from 2005 and 2007 indicates that the number of coral diseases increased from two to eight and total disease prevalence tripled between 2005 and 2011. We observed a dramatic decline in coral cover and an increase in disease prevalence at a site with a unique community of foliose corals. However, because of the 3-year period between surveys (2007, 2010), it is likely that the peak of the disease event was not observed. While multi-year studies provide useful insights into the relationships between community structure and disease, our results emphasise how determining the drivers of change in remote reef locations is especially challenging if events such as disease outbreaks are missed.
Management Evaluation for the Chesapeake Bay Blue Crab Fishery: An Integrated Bioeconomic Approach
Authors: Huang Pei , Woodward Richard T. , Wilberg Michael J. , Tomberlin David
Published: April 2015

We integrated two existing biological models and a newly developed economic demand model to evaluate the biological and economic performance of alternative policies in the Chesapeake Bay blue crab Callinectes sapidus fishery subject to the requirement that yield and revenue be sustainable. The resulting model was able to compare outcomes of alternative management scenarios considered by policy makers. In order to provide insights into the impacts of relevant policy components in a management scenario, we regressed the sustainable outcomes, sustainable yield, and sustainable revenues on a set of policy components. A short fishing season for female crabs combined with a long fishing season for males appeared to increase sustainable yield and revenue. Among size limit policies, lower minimum limits for males, females, peelers, and soft-shell crabs appeared to reduce sustainable outcomes, while a restrictive maximum size limit for mature females seemed to improve fishery performance with respect to both sustainable revenue and sustainable yield.

Received December 18, 2013; accepted November 4, 2014
Influences of Experts' Personal Experiences in Fuzzy Logic Modeling of Atlantic Salmon Habitat
Authors: Mocq J. , St-Hilaire A. , Cunjak R. A.
Published: April 2015

The knowledge of scientific experts, which is regularly used in modeling, is acquired by training, education, and practical experiences that modify the experts' perceptions. Using a case study dealing with fish habitat modeling, we investigated the possible influences and potential biases imparted by some of these personal experiences. Thirty salmon experts with different backgrounds and nationalities defined fuzzy sets and fuzzy rules in a fuzzy habitat model of three Atlantic Salmon Salmo salar life stages. Weighted usable area (WUA) curves were calculated for each expert by coupling the fuzzy model with a hydraulic model applied to the Romaine River (Quebec, Canada). Experts were then split into subgroups, and three possible experiential biases were tested: the experts' main geographic region of expertise (Europe versus North America), their primary source of knowledge (fieldwork, scientific literature, or both), and their employment sector (public or private). A confidence interval was calculated around the median WUA curve for each subgroup by bootstrap resampling. A divergence in the confidence intervals (i.e., no overlap) indicated a significant influence of the tested experience. For all three considered life stages, we observed no significant impact of employment sector or knowledge source on modeled WUA. However, the experts' geographic region of expertise had a significant influence on the output of the spawning adult habitat model. Consequently, the use of local expert knowledge in modeling is recommended.

Received June 16, 2014; accepted December 1, 2014
Article Commentary: Considerations in Civil Commitment of Individuals with Substance use Disorders
Authors: Cavaiola Alan A. , Dolan David
Published: April 2015

Several states currently have enacted laws that allow for civil commitment for individuals diagnosed with severe substance use disorders. Civil commitment or involuntary commitment refers to the legal process by which individuals with mental illness are court-ordered into inpatient and/or outpatient treatment programs. Although initially civil commitment laws were intended for individuals with severe mental illness, these statutes have been extended to cover individuals with severe substance use disorders. Much of the recent legislation allowing for civil commitment of individuals with substance use disorders has come about in response to the heroin epidemic and is designed to provide an alternative to the unrelenting progression of opioid use disorders. Civil commitment also provides an opportunity for individuals with opioid use disorders to make informed decisions regarding ongoing or continued treatment. However, civil commitment also raises concerns regarding the potential violation of 14th Amendment rights, specifically pertaining to abuses of deprivation of liberty or freedom, which are guaranteed under the 14th Amendment to the United States Constitution. This commentary examines these issues while supporting the need for effective brief civil commitment legislation in all states.
Violence and the politics of prestige: the fascist turn in colonial Libya
Authors: Ryan Eileen
Published: April 2015

In 1922–1923, Fascist Party leaders hoped to define a sharp break from previous approaches to colonial rule and imperial expansion in Italy's Libyan territories. Mussolini's nomination of Luigi Federzoni, a leading figure of the Italian Nationalist Association, as the Minister of Colonies at the end of 1922 signalled a new era in Italian colonial administration focused on aggressive expansion and the institution of what was known as a ‘politics of prestige’. This definition of a fascist style of colonial rule appealed to the enthusiasm for violence among blackshirt militias and early fascist supporters in the Libyan territories. This definition of a fascist style of colonial rule, however, inspired immediate reaction from both colonial officials, with stakes in maintaining a measure of continuity and stability, and from those within the nascent Fascist Party who wanted to promote an alternative model of fascism in the colonies. This article examines contests to define fascism and fascist colonial rule in the Libyan territories through the employment of voluntary militias, the competing voices of Fascist Party outposts, and various programmes for the development of a colonial culture.
Understanding Power in Hybrid Political Orders: Applying Stakeholder Analysis to Land Conflicts in Cambodia
Authors: Ngin Chanrith , Verkoren Willemijn
Published: April 2015

Current peacebuilding debates centre around the idea that international and local activities need to be better aligned. However, the distinction between ‘local’ and ‘international’ actors and processes obscures both power and interest differentials among actors and the various interconnections between international, national and local actors and discourses. This article proposes stakeholder analysis as a way to help understand power relations among various actors. This approach is applied to an empirical sample of land conflicts in Cambodia, in which local residents saw their livelihoods threatened by collusion between international private investors and national and local political interests. The findings suggest that building peace in insecure settings is not just a matter of harmonising approaches to strengthen the state with initiatives to support local groups. The reflex of international peacebuilders to strengthen the state and promote the rule of law overlooks the fact that governments may be unaccountable and laws may be illegitimate.
Biological invasions in the context of green roofs
Authors: Kinlocka Nicole L. , Schindler Bracha Y. , Gurevitch Jessica
Published: April 2015

Green roofs can mitigate a number of urban environmental problems when green roof plant communities provide ecosystem services. However, this perspective may fail to address ecological aspects of the plant community. In particular, it does not account for the potential for green roofs to facilitate biological invasions. We consider current research in green roof ecology in light of the literature on biological invasions, focusing on plant invasion. We evaluate the role of species composition and novel communities, species interactions, succession, and dispersal on the trajectory of green roof plant communities. Green roofs have the potential to introduce invasive species through initial plantings, to become dominated by invasive species, and to spread invasive species, and we provide recommendations for plant selection and maintenance to reduce the risks of facilitating plant invasions to surrounding communities.
The number of maximal sum-free subsets of integers
Authors: Balogh József , Liu Hong , Sharifzadeh Maryam , Treglown Andrew
Published: April 2015

Cameron and Erdős raised the question of how many maximal sum-free sets there are in

{
1
,
…
,
n
}

\{1, \dots , n\}

, giving a lower bound of

2

⌊
n

/

4
⌋

2^{\lfloor n/4 \rfloor }

. In this paper we prove that there are in fact at most

2

(
1

/

4
+
o
(
1
)
)
n

2^{(1/4+o(1))n}

maximal sum-free sets in

{
1
,
…
,
n
}

\{1, \dots , n\}

. Our proof makes use of container and removal lemmas of Green as well as a result of Deshouillers, Freiman, Sós and Temkin on the structure of sum-free sets.
A note on the two nested regular polygonal central configurations
Authors: Wang Zhiqiang , Li Fengying
Published: April 2015

This paper is concerned with nested polygonal central configurations for the Newtonian 2n-body problem. We show that when two nested regular n-polygons (

n
≥
3

n\geq 3

) with masses located at the vertices form a central configuration where the twisted angle

θ
\theta

is zero, then the value of masses in each separate polygon must be equal.
A Gysin formula for Hall-Littlewood polynomials
Authors: Pragacz Piotr
Published: April 2015

We give a formula for pushing forward the classes of Hall-Littlewood polynomials in Grassmann bundles, generalizing Gysin formulas for SchurSS- andPP-functions.
On the mixed problem for harmonic functions in a 2-D exterior cracked domain with Neumann condition on cracks
Authors: Krutitskii P.
Published: April 2015

The mixed Dirichlet-Neumann problem for the Laplace equation in an unbounded plane domain with cuts (cracks) is studied. The Dirichlet condition is given on closed curves making up the boundary of the domain, while the Neumann condition is specified on the cuts. The existence of a classical solution is proved by potential theory and a boundary integral equation method. The integral representation for a solution is obtained in the form of potentials. The density of the potentials satisfies a uniquely solvable Fredholm integral equation of the second kind and index zero. Singularities of the gradient of the solution at the tips of the cuts are investigated.
The interface coupling of the gas dynamics equations
Authors: Chalons Christophe , Raviart Pierre-Arnaud , Seguin Nicolas
Published: April 2015

We investigate the one-dimensional coupling of two systems of gas dynamics at a fixed interface. The coupling constraints consist in requiring the continuity of a system of nonconservative variables at the interface. Since we are dealing with hyperbolic systems, weak coupling conditions are proposed. The existence and the uniqueness of the solutions of the coupled Riemann problem are investigated. Several examples of solutions satisfying the weak coupling conditions are contructed, either continuous or discontinuous with respect to the nonconservative variables at the interface.
Solid-liquid phase changes with different densities
Authors: Frémond Michel , Rocca Elisabetta
Published: April 2015

In this paper we present a new thermodynamically consistent phase transition model describing the evolution of a liquid substance, e.g., water, in a rigid container

Ω
\Omega

when we freeze the container. Since the density

ϱ

2

\varrho _{2}

of ice with volume fraction

β

2

\beta _{2}

is lower than the density

ϱ

1

\varrho _{1}

of water with volume fraction

β

1

\beta _{1}

, experiments, for instance the freezing of a glass bottle filled with water, show that the water pressure increases up to the rupture of the bottle. When the container is not impermeable, freezing may produce a nonhomogeneous material, for instance water, ice or sorbet. Here we describe a general class of phase transition processes, including this example as a particular case. Moreover, we study the resulting nonlinear and singular PDE system from the analytical viewpoint, recovering existence of a global (in time) weak solution and also uniqueness for some particular choices of the nonlinear functions involved.
Recovery of multiple obstacles by probe method
Authors: Cheng Jin , Liu Jijun , Nakamura Gen , Wang Shengzhang
Published: April 2015

We consider an inverse scattering problem for multiple obstacles

D
=

⋃

j
=
1

N

D
j

⊂

R

3

D=\bigcup _{j=1}^ND_j\subset {R}^3

with different types of boundary for

D
j

D_j

. By constructing an indicator function from the far-field pattern of the scattered wave, we can firstly reconstruct the shape of all obstacles, then identify the type of boundary for each obstacle, as well as the boundary impedance in the case that obstacles have the Robin-type boundary condition. The novelty of our probe method compared with the existing probe method is that we succeeded in identifying the type of boundary condition for multiple obstacles by analyzing the behavior of both the imaginary part and the real part of the indicator function. The numerical realizations are given to show the performance of this inversion method.
Cosine effect on shallow water equations and mathematical properties
Authors: Lucas Carine
Published: April 2015

This paper presents a viscous Shallow Water type model with new Coriolis terms, and some limits according to the values of the Rossby and Froude numbers. We prove that the extension to the bidimensional case of the unidimensional results given by [J.–F. Gerbeau, B. Perthame. Discrete Continuous Dynamical Systems, (2001)] including the Coriolis force has to add new terms, omitted up to now, depending on the latitude cosine, when the viscosity is assumed to be of the order of the aspect ratio.

We show that the expressions for the waves are modified, particularly at the equator, as well as the Quasi-Geostrophic and the Lake equations. To conclude, we also study the mathematical properties of these equations.
Generalization of Euler’s equations
Authors: Ibragimov Nail
Published: April 2015

A wide class of linear ordinary differential equations reducible to algebraic equations is studied. The method for solving all these equations is given. The new class depends essentially on two arbitrary functions and contains the constant coefficient equations and Euler’s equations as particular cases.
Polynomial decay to thermoelastic plates with memory
Authors: Romero Pedro
Published: April 2015

We consider the linear model of thermoelastic plates with memory and we show that the solution decays polynomially with rates that depend on the regularity of the initial data.
Justification of a Galerkin method for a regularized Cauchy singular integro-differential equation
Authors: Fedotov A.
Published: April 2015

For one class of the singular integro-differential equations with Cauchy kernel on an interval, a Galerkin method is justified. The convergence is proved and the error estimation is given.
On the stability of shock waves in layered structures at the presence of the electric current
Authors: Blokhin A. , Semenko R.
Published: April 2015

We are concerned with a hydrodynamical model of layered structures at the presence of the electric current. We formulate a linearized stability problem for shock waves and prove its ill-posedness, which means instability of shock waves for the given model of layered structures.
Two stable-by-homogenization models in simple shearing of rate-dependent non-homogeneous materials
Authors: Charalambakis Nicolas , Murat François
Published: April 2015

In this paper we study two models, the viscoplastic model and the thermoviscous model, of rate-dependent non-homogeneous materials with non-oscillating strain-rate sensitivity submitted to simple quasistatic shearing. We prove that the two models are stable by homogenization, i.e. that the equations in both the heterogeneous problems and the homogenized one have the same form, and we give explicit formulas for the homogenized (effective) coefficients. These formulas depend on the initial conditions, but not on the boundary conditions. Our theoretical results are illustrated by a numerical example.
Variational problems in weighted Sobolev spaces on non-smooth domains
Authors: Soane Ana Maria , Rostamian Rouben
Published: April 2015

We study the Poisson problem

−
Δ
u
=
f

-\Delta u = f

and the Helmholtz problem

−
Δ
u
+
λ
u
=
f

-\Delta u + \lambda u = f

in bounded domains with angular corners in the plane and

u
=
0

u=0

on the boundary. On non-convex domains of this type, the solutions are in the Sobolev space

H
1

H^1

but not in

H
2

H^2

in general, even though

f
f

may be very regular. We formulate these as variational problems in weighted Sobolev spaces and prove existence and uniqueness of solutions in what would be weighted counterparts of

H
2

∩

H
0
1

H^2 \cap H^1_0

.

The specific forms of our variational formulations are motivated by, and are particularly suited to, applying a finite element scheme for solving the time-dependent Navier-Stokes equations of fluid mechanics.
Existence of traveling waves in a simple isothermal chemical system with the same order for autocatalysis and decay
Authors: Tsai Je-Chiang
Published: April 2015

The reaction-diffusion systems which are based on an isothermal autocatalytic chemical reaction involving both an autocatalytic step of the

(
m
+
1
)

(m+1)

th order (

A
+
m
B
→
(
m
+
1
)
B

A+mB\rightarrow (m+1)B

) and a decay step of the same order (

B
→
C

B\rightarrow C

) have very rich and interesting dynamics. Previous studies in the literature indicate that traveling waves play a key role in understanding these interesting dynamical phenomena. However, there is a lack of rigorous proof of the existence of traveling waves to this system. Here we generalize this isothermal autocatalytic chemical reaction model and provide a rigorous proof of the existence of traveling waves for the resulting reaction-diffusion system which also includes the systems arising from epidemiology and the microbial growth in a flow reactor.
Remark on a regularity criterion in terms of pressure for the Navier-Stokes equations
Authors: Gala Sadek
Published: April 2015

In this note we establish a Serrin-type regularity criterion in terms of pressure for Leray weak solutions to the Navier-Stokes equation in

R

d

\mathbb {R}^{d}

. It is known that if a Leray weak solution

u
u

belongs to
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper L Superscript StartFraction 2 Over 1 minus r EndFraction Baseline left-parenthesis left-parenthesis 0 comma upper T right-parenthesis semicolon upper L Superscript StartFraction d Over r EndFraction Baseline right-parenthesis reverse-solidus reverse-solidus for some reverse-solidus reverse-solidus 0 less-than-or-equal-to r less-than-or-equal-to 1 comma">

L

2

1
−
r

(

(
0
,
T
)

;

L

d
r

)

 \ \ for some \ \ 
0
≤
r
≤
1
,

\begin{equation} L^{\frac {2}{1-r}}\left ( \left ( 0,T\right ) ;L^{\frac {d}{r}}\right ) \text { \ \ for some \ \ }0\leq r\leq 1, \end{equation}

then

u
u

is regular. It is proved that if the pressure

p
p

associated to a Leray weak solution

u
u

belongs to
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper L Superscript StartFraction 2 Over 2 minus r EndFraction Baseline left-parenthesis left-parenthesis 0 comma upper T right-parenthesis semicolon ModifyingAbove script upper M With period Subscript 2 comma StartFraction d Over r EndFraction Baseline left-parenthesis double-struck upper R Superscript d Baseline right-parenthesis Superscript d Baseline right-parenthesis comma">

L

2

2
−
r

(

(
0
,
T
)

;

M

.

2
,

d
r

(

R

d

)

d

)

,

\begin{equation} L^{\frac {2}{2-r}}\left ( \left ( 0,T\right ) ;\overset {.}{\mathcal {M}}_{2,\frac { d}{r}}\left ( \mathbb {R}^{d}\right ) ^{d}\right ) , \end{equation}

where

M

.

2
,

d
r

(

R

d

)

\overset {.}{\mathcal {M}}_{2,\frac {d}{r}}\left ( \mathbb {R}^{d}\right )

is the critical Morrey-Campanato space (a definition is given in the text) for

0
>
r
>
1

0>r>1

, then the weak solution is actually regular. Since this space

M

.

2
,

d
r

\overset {.}{\mathcal {M}}_{2,\frac {d}{r}}

is wider than

L

d
r

L^{\frac {d}{r}}

and

X
.

r

\overset {.}{X}_{r}

, the above regularity criterion (0.2) is an improvement of Zhou’s result.
Pat1 protects centromere-specific histone H3 variant Cse4 from Psh1-mediated ubiquitination
Authors: Mishra Prashant K. , Guo Jiasheng , Dittman Lauren E. , Haase Julian , Yeh Elaine , Bloom Kerry , Basrai Munira A.
Published: April 2015

Evolutionarily conserved histone H3 variant Cse4 and its homologues are essential components of specialized centromere ( CEN)-specific nucleosomes and serve as an epigenetic mark for CEN identity and propagation. Cse4 is a critical determinant for the structure and function of the kinetochore and is required to ensure faithful chromosome segregation. The kinetochore protein Pat1 regulates the levels and spatial distribution of Cse4 at centromeres. Deletion of PAT1 results in altered structure of CEN chromatin and chromosome segregation errors. In this study, we show that Pat1 protects CEN-associated Cse4 from ubiquitination in order to maintain proper structure and function of the kinetochore in budding yeast. PAT1-deletion strains exhibit increased ubiquitination of Cse4 and faster turnover of Cse4 at kinetochores. Psh1, a Cse4-specific E3-ubiquitin ligase, interacts with Pat1 in vivo and contributes to the increased ubiquitination of Cse4 in pat1∆ strains. Consistent with a role of Psh1 in ubiquitination of Cse4, transient induction of PSH1 in a wild-type strain resulted in phenotypes similar to a pat1∆ strain, including a reduction in CEN-associated Cse4, increased Cse4 ubiquitination, defects in spatial distribution of Cse4 at kinetochores, and altered structure of CEN chromatin. Pat1 interacts with Scm3 and is required for its maintenance at kinetochores. In conclusion, our studies provide novel insights into mechanisms by which Pat1 affects the structure of CEN chromatin and protects Cse4 from Psh1-mediated ubiquitination for faithful chromosome segregation.
Glycogen synthase kinase-3 (Gsk-3) plays a fundamental role in maintaining DNA methylation at imprinted loci in mouse embryonic stem cells
Authors: Meredith Gavin D. , D'Ippolito Anthony , Dudas Miroslav , Zeidner Leigh C. , Hostetter Logan , Faulds Kelsie , Arnold Thomas H. , Popkie Anthony P. , Doble Bradley W. , Marnellos George , Adams Christopher , Wang Yulei , Phiel Christopher J.
Published: April 2015

Glycogen synthase kinase-3 (Gsk-3) is a key regulator of multiple signal transduction pathways. Recently we described a novel role for Gsk-3 in the regulation of DNA methylation at imprinted loci in mouse embryonic stem cells (ESCs), suggesting that epigenetic changes regulated by Gsk-3 are likely an unrecognized facet of Gsk-3 signaling. Here we extend our initial observation to the entire mouse genome by enriching for methylated DNA with the MethylMiner kit and performing next-generation sequencing (MBD-Seq) in wild-type and Gsk-3α−/−;Gsk-3β−/−ESCs. Consistent with our previous data, we found that 77% of known imprinted loci have reduced DNA methylation in Gsk-3-deficient ESCs. More specifically, we unambiguously identified changes in DNA methylation within regions that have been confirmed to function as imprinting control regions. In many cases, the reduced DNA methylation at imprinted loci in Gsk-3α−/−;Gsk-3β−/−ESCs was accompanied by changes in gene expression as well. Furthermore, many of the Gsk-3–dependent, differentially methylated regions (DMRs) are identical to the DMRs recently identified in uniparental ESCs. Our data demonstrate the importance of Gsk-3 activity in the maintenance of DNA methylation at a majority of the imprinted loci in ESCs and emphasize the importance of Gsk-3–mediated signal transduction in the epigenome.
Misfolding of mutant adenine nucleotide translocase in yeast supports a novel mechanism of Ant1-induced muscle diseases
Authors: Liu Yaxin , Wang Xiaowen , Chen Xin Jie
Published: April 2015

Approximately one-third of proteins in the cell reside in the membrane. Mutations in membrane proteins can induce conformational changes and expose nonnative polar domains/residues to the lipid environment. The molecular effect of the resulting membrane stress is poorly defined. Adenine nucleotide translocase 1 (Ant1) is a mitochondrial inner membrane protein involved in ATP/ADP exchange. Missense mutations in the Ant1 isoform cause autosomal dominant progressive external ophthalmoplegia (adPEO), cardiomyopathy, and myopathy. The mechanism of the Ant1-induced pathologies is highly debated. Here we show that equivalent mutations in the yeast Aac2 protein cause protein misfolding. Misfolded Aac2 drastically affects the assembly and stability of multiple protein complexes in the membrane, which ultimately inhibits cell growth. Despite causing similar proteostatic damages, the adPEO- but not the cardiomyopathy/myopathy-type Aac2 proteins form large aggregates. The data suggest that the Ant1-induced diseases belong to protein misfolding disorders. Protein homeostasis is subtly maintained on the mitochondrial inner membrane and can be derailed by the misfolding of one single protein with or without aggregate formation. This finding could have broad implications for understanding other dominant diseases (e.g., retinitis pigmentosa) caused by missense mutations in membrane proteins.
Implications for informatics given expanding access to care for Veterans and other populations
Authors: Dixon Brian E , Haggstrom David A , Weiner Michael
Published: April 2015

Recent investigations into appointment scheduling within facilities operated by the US Department of Veterans Affairs (VA) illuminate systemic challenges in meeting its goal of providing timely access to care for all Veterans. In the wake of these investigations, new policies have been enacted to expand access to care at VA facilities as well as non-VA facilities if the VA is unable to provide access within a reasonable timeframe or a Veteran lives more than 40 miles from a VA medical facility. These policies are similar to broader health reform efforts that seek to expand access to care for other vulnerable populations. In this perspective, we discuss the informatics implications of expanded access within the VA and its wider applicability across the US health system. Health systems will require robust health information exchange, to maintain coordination while access to care is expanded. Existing informatics research can guide short-term implementation; furthermore, new research is needed to generate evidence about how best to achieve the long-term aim of expanded access to care.
Wind-induced odd gravitational harmonics of Jupiter
Authors: Kong Dali , Zhang Keke , Schubert Gerald
Published: April 2015

While the rotational distortion of Jupiter makes a major contribution to its lowermost order even zonal gravitational coefficients Jn with n ≥ 2, the component of the zonal winds with equatorial antisymmetry, if sufficiently deep, produces a gravitational signature contained in the odd zonal gravitational coefficients Jn with n ≥ 3. Based on a non-spherical model of a polytropic Jupiter with index unity, we compute Jupiter's odd gravitational coefficients J3, J5, J7, …, J11 induced by the equatorially antisymmetric zonal winds that are assumed to be deep. It is found that the lowermost odd gravitational coefficients J3, J5 and J7 are of the same order of magnitude with J3 = −1.6562 × 10−6, J5 = 1.5778 × 10−6 and J7 = −0.7432 × 10−6, and are within the accuracy of high-precision gravitational measurements to be carried out by the Juno spacecraft.
Raising the bar: new constraints on the Hubble parameter with cosmic chronometers at z ∼ 2
Authors: Moresco Michele
Published: April 2015

One of the most compelling tasks of modern cosmology is to constrain the expansion history of the Universe, since this measurement can give insights on the nature of dark energy and help to estimate cosmological parameters. In this letter are presented two new measurements of the Hubble parameter H(z) obtained with the cosmic chronometer method up to z ∼ 2. Taking advantage of near-infrared spectroscopy of the few very massive and passive galaxies observed at z > 1.4 available in literature, the differential evolution of this population is estimated and calibrated with different stellar population synthesis models to constrain H(z), including in the final error budget all possible sources of systematic uncertainties (star formation history, stellar metallicity, model dependences). This analysis is able to extend significantly the redshift range coverage with respect to present-day constraints, crossing for the first time the limit at z ∼ 1.75. The new H(z) data are used to estimate the gain in accuracy on cosmological parameters with respect to previous measurements in two cosmological models, finding a small but detectable improvement (∼5 per cent) in particular on ΩM and w0. Finally, a simulation of a Euclid-like survey has been performed to forecast the expected improvement with future data. The provided constraints have been obtained just with the cosmic chronometers approach, without any additional data, and the results show the high potentiality of this method to constrain the expansion history of the Universe at these redshifts.
Hadronic models of blazars require a change of the accretion paradigm
Authors: Zdziarski Andrzej A. , Böttcher Markus
Published: April 2015

We study hadronic models of broad-band emission of jets in radio-loud active galactic nuclei, and their implications for the accretion in those sources. We show that the models that account for broad-band spectra of blazars emitting in the GeV range in the sample of Böttcher et al. have highly super-Eddington jet powers. Furthermore, the ratio of the jet power to the radiative luminosity of the accretion disc is ∼3000 on average and can be as high as ∼105. We then show that the measurements of the radio core shift for the sample imply low magnetic fluxes threading the black hole, which rules out the Blandford–Znajek mechanism to produce powerful jets. These results require that the accretion rate necessary to power the modelled jets is extremely high, and the average radiative accretion efficiency is ∼4 × 10−5. Thus, if the hadronic model is correct, the currently prevailing picture of accretion in AGNs needs to be significantly revised. Also, the obtained accretion mode cannot be dominant during the lifetimes of the sources, as the modelled very high accretion rates would result in too rapid growth of the central supermassive black holes. Finally, the extreme jet powers in the hadronic model are in conflict with the estimates of the jet power by other methods.
Low-mass X-ray binary MAXI  J1421−613 observed by MAXI GSC and Swift XRT
Authors: Serino Motoko , Shidatsu Megumi , Ueda Yoshihiro , Matsuoka Masaru , Negoro Hitoshi , Yamaoka Kazutaka , Kennea Jamie A. , Fukushima Kosuke , Nagayama Takahiro
Published: April 2015

Monitor of All sky X-ray Image (MAXI) discovered a new outburst of an X-ray transient source named MAXI  J1421−613. Because of the detection of three X-ray bursts from the source, it was identified as a neutron star low-mass X-ray binary. The results of data analyses of the MAXI GSC (Gas Slit Camera) and the Swift XRT (X-Ray Telescope) follow-up observations suggest that the spectral hardness remained unchanged during the first two weeks of the outburst. All the XRT spectra in the 0.5–10 keV band can be well explained by thermal Comptonization of multi-color disk blackbody emission. The photon index of the Comptonized component is ≈ 2, which is typical of low-mass X-ray binaries in the low/hard state. Since X-ray bursts have a maximum peak luminosity, it is possible to estimate the (maximum) distance from its observed peak flux. The peak flux of the second X-ray burst, which was observed by the GSC, is about 5 photons cm−2 s−1. By assuming a blackbody spectrum of 2.5 keV, the maximum distance to the source is estimated as 7 kpc. The position of this source is contained by the large error regions of two bright X-ray sources detected with Orbiting Solar Observatory-7 (OSO-7) in the 1970s. Besides this, no past activities at the XRT position are reported in the literature. If MAXI  J1421−613 is the same source as (one of) these, the outburst observed with MAXI may have occurred after a quiescence of 30–40 years.