bluuebunny/crossref_metadata_2025 huggingface dataset:
Maximal functions and singular integrals associated to polynomial mappings of $\mathbb{R}^n$
Authors: Carbery Anthony , Ricci Fulvio , Wright James
Published: December 2011

We consider convolution operators on

\mathbb{R}^n

of the form

T_Pf(x) =\int_{\mathbb{R}^m} f\big(x-P(y)\big)K(y) dy

, where

P

is a polynomial defined on

\mathbb{R}^m

with values in

\mathbb{R}^n

and

K

is a smooth Calderón-Zygmund kernel on

\mathbb{R}^m

. A maximal operator

M_P

can be constructed in a similar fashion. We discuss weak-type 1-1 estimates for

T_P

and

M_P

and the uniformity of such estimates with respect to

P

. We also obtain

L^p

-estimates for "supermaximal" operators, defined by taking suprema over

P

ranging in certain classes of polynomials of bounded degree.
Small global solutions and the nonrelativistic limit for the nonlinear Dirac equation
Authors: Machihara Shuji , Nakanishi Kenji , Ozawa Tohru
Published: December 2011

In this paper we study the Cauchy problem for the nonlinear Dirac equation in the Sobolev space

H^s

. We prove the existence and uniqueness of global solutions for small data in

H^s

with

s>1

. The method of proof is based on the Strichartz estimate of

L^2_t

type for Dirac and Klein-Gordon equations. We also prove that the solutions of the nonlinear Dirac equation after modulation of phase converge to the corresponding solutions of the nonlinear Schröodinger equation as the speed of light tends to infinity.
Galois theory of special trinomials
Authors: Abhyankar Shreeram S.
Published: December 2011

This is the material which I presented at the 60th birthday conference of my good friend Jos\'{e} Luis Vicente in Seville in September 2001. It is based on the nine lectures, now called sections, which were given by me at Purdue in Spring 1997. This should provide a good calculational background for the Galois theory of vectorial (= additive) polynomials and their iterates.
Perturbing plane curve singularities
Authors: Casas-Alvero Eduardo , Peraire Rosa
Published: December 2011

We describe the singularity of all but finitely-many germs in a pencil generated by two germs of plane curve sharing no tangent.
Conservation of the noetherianity by perfect transcendental field extensions
Authors: Fernández Lebrón Magdalena , Narváez Macarro Luis
Published: December 2011

Let

k

be a perfect field of characteristic

p>0

,

k(t)_{per}

the perfect closure of

k(t)

and

A

a

k

-algebra. We characterize whether the ring

A\otimes_k k(t)_{per}=\bigcup_{m\geq 0}(A\otimes_k k(t^{\frac{1}{p^m}}))

is noetherian or not. As a consequence, we prove that the ring

A\otimes_k k(t)_{per}

is noetherian when

A

is the ring of formal power series in

n

indeterminates over

k

.
Proximity relations for real rank one valuations dominating a local regular ring
Authors: Granja Ángel , Rodríguez Cristina
Published: December 2011

We study 0-dimensional real rank one valuations centered in a regular local ring of dimension

n\geq 2

such that the associated valuation ring can be obtained from the regular ring by a sequence of quadratic transforms. We define two classical invariants associated to the valuation (the refined proximity matrix and the multiplicity sequence) and we show that are equivalent data of the valuation.
A Computer Algebra Solution to a Problem in Finite Groups
Authors: Greuel Gert-Martin
Published: December 2011

We report on a partial solution of the conjecture that the class of finite solvable groups can be characterised by 2-variable identities. The proof requires pieces from number theory, algebraic geometry, singularity theory and computer algebra. The computations were carried out using the computer algebra system SINGULAR.
Slopes of hypergeometric systems of codimension one
Authors: Hartillo Hermoso María Isabel
Published: December 2011

We describe the slopes, with respect to the coordinates hyperplanes, of the hypergeometric systems of codimension one, that is when the toric ideal is generated by one element.
Asymptotic behavior of the energy and pointwise estimates for solutions to the Navier-Stokes equations
Authors: Brandolese Lorenzo
Published: December 2011

We study the large time behavior of the energy of a class of Navier-Stokes flows in

\mathbb{R}^n

(n\ge2)

with special symmetries. Inside this class, we construct examples of solutions such that the energy norm decays faster than

t^{-(n+2)/4}

.
Application of accretive operators theory to evolutive combined conduction, convection and radiation
Authors: Porzio Maria Michaela , López-Pouso Óscar
Published: December 2011

The accretive operators theory is employed for proving an existence theorem for the evolutive energy equations involving simultaneously conduction, stationary convection (in the sense that the velocity field is assumed to be time independent), and radiation. In doing that we need to use new existence results for elliptic linear problems with mixed boundary conditions and irregular data.
Hausdorff dimension of the graph of the Fractional Brownian Sheet
Authors: Ayache Antoine
Published: December 2011

Let

\{B^{(\alpha)}(t)\}_{t\in\mathbb{R}^{d}}

be the Fractional Brownian Sheet with multi-index

\alpha=(\alpha_1,\ldots, \alpha_d)

,

0< \alpha_i< 1

. In [14], Kamont has shown that, with probability

1

, the box dimension of the graph of a trajectory of this Gaussian field, over a non-degenerate cube

Q\subset\mathbb{R}^{d}

is equal to

d+1-\min(\alpha_1,\ldots,\alpha_d)

. In this paper, we prove that this result remains true when the box dimension is replaced by the Hausdorff dimension or the packing dimension.
The Magic Square and Symmetric Compositions
Authors: Elduque Alberto
Published: December 2011

The new construction given by Barton and Sudbery of the Freudenthal-Tits magic square, which includes the exceptional classical simple Lie algebras, will be interpreted and extended by using a pair of symmetric composition algebras, instead of the standard unital composition algebras.
The Singularity of Orbital Measures on Compact Lie Groups
Authors: Hare Kathryn E. , Yee Wai Ling
Published: December 2011

We find the minimal real number

k

such that the

k

th power of the Fourier transform of any continuous, orbital measure on a classical, compact Lie group belongs to

l^{2}

. This results from an investigation of the pointwise behaviour of characters on these groups. An application is given to the study of

L^{p}

-improving measures.
Algebras of Toeplitz operators with oscillating symbols
Authors: Böttcher Albrecht , Grudsky Sergei M. , Ramírez de Arellano Enrique
Published: December 2011

This paper is devoted to Banach algebras generated by Toeplitz operators with strongly oscillating symbols, that is, with symbols of the form

b(e^{i\alpha(x)})

where

b

belongs to some algebra of functions on the unit circle and

\alpha

is a fixed orientation-preserving homeomorphism of the real line onto itself. We prove the existence of certain interesting homomorphisms and establish conditions for the normal solvability, Fredholmness, and invertibility of operators in these algebras.
Resolution of a family of Galois embedding problems with cyclic kernel
Authors: Vela Montserrat
Published: December 2011

In this paper we compute the obstruction and the solutions of cyclic embedding problems given by

(E): \quad 0 \rightarrow \mathbb{Z}/n\mathbb{Z} \rightarrow E \rightarrow \Gamma=\mathbb{Z}/n\mathbb{Z} \times \stackrel{m)}{\cdots} \times \mathbb{Z}/n\mathbb{Z} \rightarrow 0 ,

with

\mathbb{Z}/n\mathbb{Z}

trivial

\Gamma

-modulo, finding adequate representations of

\Gamma

in the automorphisms group of a generalized Clifford algebra.
Estimates in Besov spaces for transport and transport-diffusion equations with almost Lipschitz coefficients
Authors: Danchin Raphaël
Published: December 2011

This paper aims at giving an overview of estimates in general Besov spaces for the Cauchy problem on

t=0

related to the vector field

\partial_t+v\cdot\nabla

. The emphasis is on the conservation or loss of regularity for the initial data. When

\nabla v

belongs to

L^1(0,T;L^\infty)

(plus some convenient conditions depending on the functional space considered for the data), the initial regularity is preserved. On the other hand, if

\nabla v

is slightly less regular (e.g.

\nabla v

belongs to some limit space for which the embedding in

L^\infty

fails), the regularity may coarsen with time. Different scenarios are possible going from linear to arbitrarily small loss of regularity. This latter result will be used in a forthcoming paper to prove global well-posedness for two-dimensional incompressible density-dependent viscous fluids (see [Danchin, R.: Local theory in critical spaces for compressible viscous and heat-conductive gases. Comm. Partial Differential Equations 26 (2001), 1183-1233, and Erratum, 27 (2002), 2531-2532.]). Besides, our techniques enable us to get estimates uniformly in

\nu\geq0

when adding a diffusion term

-\nu\Delta u

to the transport equation.
Poches de tourbillon singulières dans un fluide faiblement visqueux
Authors: Hmidi Taoufik
Published: December 2011

In this paper, we study the singular vortex patches in the two-dimensional incompressible Navier-Stokes equations. We show, in particular, that if the initial vortex patch is

C^{1+s}

outside a singular set

\Sigma

, so the velocity is, for all time, lipschitzian outside the image of

\Sigma

through the viscous flow. In addition, the correponding lipschitzian norm is independant of the viscosity. This allows us to prove some results related to the inviscid limit for the geometric structures of the vortex patch.
The existence of positive solution to some asymptotically linear elliptic equations in exterior domains
Authors: Li Gongbao , Zheng Gao-Feng
Published: December 2011

In this paper, we are concerned with the asymptotically linear elliptic problem

-\Delta u+ \lambda_{0}u=f(u), u\in H_{0}^{1}(\Omega )

in an exterior domain

\Omega= \mathbb{R}^{N}\setminus\overline{\mathcal{O}} \left( N\geqslant 3\right)

with

\mathcal{O}

a smooth bounded and star-shaped open set, and

\lim_{t\rightarrow +\infty }\frac{ f(t)}{t}=l

,

0<l<+\infty

. Using a precise deformation lemma and algebraic topology argument, we prove under our assumptions that the problem possesses at least one positive solution.
On Falconer’s Distance Set Conjecture
Authors: Erdoğan M. Burak
Published: December 2011

In this paper, using a recent parabolic restriction estimate of Tao, we obtain improved partial results in the direction of Falconer's distance set conjecture in dimensions

d\geq 3

.
The Structure of Linear Extension Operators for $C^m$
Authors: Fefferman Charles
Published: December 2011

For any subset

E \subset \mathbb{R}^n

, let

C^m (E)

denote the Banach space of restrictions to

E

of functions

F \in C^m (\mathbb{R}^n)

. It is known that there exist bounded linear maps

T:C^m(E)\longrightarrow C^m(\mathbb{R}^n)

such that

Tf = f

on

E

for any

f \in C^m (E)

. We show that

T

can be taken to have a simple form, but cannot be taken to have an even simpler form.
The punishing factors for convex pairs are $2^{n-1}$
Authors: Avkhadiev Farit G. , Wirths Karl-Joachim
Published: December 2011

Let

\Omega

and

\Pi

be two simply connected proper subdomains of the complex plane

\mathbb{C}

. We are concerned with the set

A(\Omega,\Pi)

of functions

f: \Omega\longrightarrow\Pi

holomorphic on

\Omega

and we prove estimates for

|f^{(n)}(z)|, f \in A(\Omega,\Pi), z \in \Omega

, of the following type. Let

\lambda_{\Omega}(z)

and

\lambda_{\Pi}(w)

denote the density of the Poincaré metric with curvature

K=-4

of

\Omega

at

z

and of

\Pi

at

w

, respectively. Then for any pair

(\Omega,\Pi)

of convex domains,

f \in A(\Omega,\Pi), z \in \Omega

, and

n\geq 2

the inequality

\frac{|f^{(n)}(z)|}{n!}\leq 2^{n-1}\frac{(\lambda_{\Omega}(z))^n}{\lambda_{\Pi}(f(z))}

is valid. The constant

2^{n-1}

is best possible for any pair

(\Omega,\Pi)

of convex domains. For any pair

(\Omega,\Pi)

, where

\Omega

is convex and

\Pi

linearly accessible,

f,z,n

as above, we prove

\frac{|f^{(n)}(z)|}{(n+1)!}\leq 2^{n-2}\frac{(\lambda_{\Omega}(z))^n}{\lambda_{\Pi}(f(z))}.

The constant

2^{n-2}

is best possible for certain admissible pairs

(\Omega,\Pi)

. These considerations lead to a new, nonanalytic, characterization of bijective convex functions

h:\Delta\to\Omega

not using the second derivative of

h

.
Convergents and irrationality measures of logarithms
Authors: Rivoal Tanguy
Published: December 2011

We prove new irrationality measures with restricted denominators of the form

\mathrm{d}_{\lfloor\nu m\rfloor}^s B^m

(where

B, m \in\mathbb{N}, \nu > 0

,

s\in\{0,1\}

and

\mathrm{d}_m=\textup{lcm}\{1,2, \ldots, m\}

) for values of the logarithm at certain rational numbers

r>0

. In particular, we show that such an irrationality measure of

\log(r)

is arbitrarily close to 1 provided

r

is sufficiently close to 1. This implies certain results on the number of non-zero digits in the

b

-ary expansion of

\log(r)

and on the structure of the denominators of convergents of

\log(r)

. No simple method for calculating the latter is known. For example, we show that, given integers

a,c\ge 1

, for all large enough

b, n

, the denominator

q_n

of the

n

-th convergent of

\log(1\pm a/b)

cannot be written under the form

\mathrm d_{\lfloor\nu m\rfloor}^s (bc)^m

: this is true for

a=c=1

,

b \ge 12

when

s=0

, resp.

b \ge 2

when

s=1

and

\nu=1

. Our method rests on a detailed diophantine analysis of the upper Padé table

([p/q])_{p\ge q\ge 0}

of the function

\log(1-x)

. Finally, we remark that worse results (of this form) are currently provable for the exponential function, despite the fact that the complete Padé table

([p/q])_{p, q\ge 0}

of

\exp(x)

and the convergents of

\exp(1/b)

, for

\vert b\vert \ge 1

, are well-known, for example.
$L^2$ boundedness for commutator of rough singular integral with variable kernel
Authors: Chen Yanping , Ding Yong
Published: December 2011

n this paper the authors prove the

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

boundedness of the commutator of the singular integral operator with rough variable kernels, which is a substantial improvement and extension of some known results.
Stable Higgs $G$-sheaves
Authors: Gómez Tomás , Sols Ignacio
Published: December 2011

For a connected reductive group

G

, we generalize the notion of (semi)stable Higgs

G

-bundles on curves to smooth projective schemes of higher dimension, allowing also Higgs

G

-sheaves, and construct the corresponding moduli space.
Tropical resultants for curves and stable intersection
Authors: Tabera Alonso Luis Felipe
Published: December 2011

We introduce the notion of resultant of two planar curves in the tropical geometry framework. We prove that the tropicalization of the algebraic resultant can be used to compute the stable intersection of two tropical plane curves. It is shown that, for two generic preimages of the curves to an algebraic framework, their intersection projects exactly onto the stable intersection of the curves. It is also given sufficient conditions for such a generality in terms of the residual coefficients of the algebraic coefficients of defining equations of the curves.
Multiparameter singular integrals and maximal operators along flat surfaces
Authors: Cho Yong-Kum , Hong Sunggeum , Kim Joonil , Yang Chan Woo
Published: December 2011

We study double Hilbert transforms and maximal functions along surfaces of the form

(t_1,t_2,\gamma_1(t_1)\gamma_2(t_2))

. The

L^p(\mathbb{R}^3)

boundedness of the maximal operator is obtained if each

\gamma_i

is a convex increasing and

\gamma_i(0)=0

. The double Hilbert transform is bounded in

L^p(\mathbb{R}^3)

if both

\gamma_i

's above are extended as even functions. If

\gamma_1

is odd, then we need an additional comparability condition on

\gamma_2

. This result is extended to higher dimensions and the general hyper-surfaces of the form

(t_1,\dots,t_{n},\Gamma(t_1,\dots,t_{n}))

on

\mathbb{R}^{n+1}

.
An example related to Whitney extension with almost minimal $C^m$ norm
Authors: Fefferman Charles , Klartag Bo'az
Published: December 2011

We present a counter-example to a certain conjecture that is related to Whitney's extension problems.
Small solutions to semi-linear wave equations with radial data of critical regularity
Authors: Hidano Kunio
Published: December 2011

This paper investigates the problem of global existence of small solutions to semi-linear wave equations with radially symmetric data of critical regularity. Under radial symmetry we focus on the case where the power of nonlinear term is somewhat smaller than the conformal power. Our result covers the case where the power is strictly larger than the John-Glassey exponent in two or three space dimensions. In higher dimension it applies to the equation whose power is strictly larger than the

L^2

-critical exponent. The main theorem is therefore an improvement over a previous result due to Lindblad and Sogge. The new ingredient in our proof is an effective use of some weighted estimates of radially symmetric solutions to inhomogeneous wave equations.
Algorithmic equiresolution of deformations of embedded varieties
Authors: Nobile Augusto
Published: December 2011

A theory of simultaneous resolution of singularities for families of embedded varieties (over a field of characteristic zero) parametrized by the spectrum of a suitable artinian ring, and compatible with a given algorithm of resolution, is presented. As usually, this a simple consequence of a similar theory for analogous families of basic objects, to which the main portion of this article is devoted.
Lebesgue points and the fundamental convergence theorem for superharmonic functions on metric spaces
Authors: Björn Anders , Björn Jana , Parviainen Mikko
Published: December 2011

We prove the nonlinear fundamental convergence theorem for superharmonic functions on metric measure spaces. Our proof seems to be new even in the Euclidean setting. The proof uses direct methods in the calculus of variations and, in particular, avoids advanced tools from potential theory. We also provide a new proof for the fact that a Newtonian function has Lebesgue points outside a set of capacity zero, and give a sharp result on when superharmonic functions have

L^q

-Lebesgue points everywhere.
Wellposedness and regularity of solutions of an aggregation equation
Authors: Li Dong , Rodrigo José L.
Published: December 2011

We consider an aggregation equation in

\mathbb R^d

,

d\ge 2

with fractional dissipation:

u_t + \nabla\cdot(u \nabla K*u)=-\nu \Lambda^\gamma u

, where

\nu\ge 0

,

0 < \gamma\le 2

and

K(x)=e^{-|x|}

. In the supercritical case,

0 < \gamma < 1

, we obtain new local wellposedness results and smoothing properties of solutions. In the critical case,

\gamma=1

, we prove the global wellposedness for initial data having a small

L_x^1

norm. In the subcritical case,

\gamma > 1

, we prove global wellposedness and smoothing of solutions with general

L_x^1

initial data.
Isoperimetry for spherically symmetric log-concave probability measures
Authors: Huet Nolwen
Published: December 2011

We prove an isoperimetric inequality for probability measures

\mu

on

\mathbb{R}^n

with density proportional to

\exp(-\phi(\lambda |x|))

, where

|x|

is the euclidean norm on

\mathbb{R}^n

and

\phi

is a non-decreasing convex function. It applies in particular when

\phi(x)=x^\alpha

with

\alpha \ge 1

. Under mild assumptions on

\phi

, the inequality is dimension-free if

\lambda

is chosen such that the covariance of

\mu

is the identity.
Cluster solutions for the Schrödinger-Poisson-Slater problem around a local minimum of the potential
Authors: Ruiz David , Vaira Giusi
Published: December 2011

In this paper we consider the system in

\mathbb{R}^3

\left\{ \begin{array}{l} -\varepsilon^2 \Delta u + V(x)u + \phi(x)u = u^p, \\ -\Delta \phi = u^2, \end{array} \right.

for

p\in (1,5)

. We prove the existence of multi-bump solutions whose bumps concentrate around a local minimum of the potential

V(x)

. We point out that such solutions do not exist in the framework of the usual Nonlinear Schrödinger Equation.
Pseudo-localisation of singular integrals in $L^p$
Authors: Hytönen Tuomas
Published: December 2011

As a step in developing a non-commutative Calderón-Zygmund theory, J. Parcet (J. Funct. Anal. {\bf 256} (2009), no. 2, 509-593) established a new pseudo-localisation principle for classical singular integrals, showing that

Tf

has small

L^2

norm outside a set which only depends on

f\in L^2

but not on the arbitrary normalised Calderón-Zygmund operator

T

. Parcet also asked if a similar result holds true in

L^p

for

p\in(1,\infty)

. This is answered in the affirmative in the present paper. The proof, which is based on martingale techniques, even somewhat improves on the original

L^2

result.
Finiteness of endomorphism algebras of CM modular abelian varieties
Authors: González Rovira Josep
Published: December 2011

Let

A_f

be the abelian variety attached by Shimura to a normalized newform

f\in S_2(\Gamma_1(N))^{\operatorname{new}}

. We prove that for any integer

n > 1

the set of pairs of endomorphism algebras

\big( \operatorname{End}_{\overline{\mathbb{Q}}}(A_f) \otimes \mathbb{Q}, \operatorname{End}_\mathbb{Q}(A_f) \otimes \mathbb{Q} \big)

obtained from all normalized newforms

f

with complex multiplication such that

\dim A_f=n

is finite. We determine that this set has exactly 83 pairs for the particular case

n=2

and show all of them. We also discuss a conjecture related to the finiteness of the set of number fields

\operatorname{End}_\mathbb{Q}(A_f) \otimes \mathbb{Q}

for the non-CM case.
Geometric-arithmetic averaging of dyadic weights
Authors: Pipher Jill , Ward Lesley A. , Xiao Xiao
Published: December 2011

The theory of Muckenhoupt's weight functions arises in many areas of analysis, for example in connection with bounds for singular integrals and maximal functions on weighted spaces. We prove that a certain averaging process gives a method for constructing

A_p

weights from a measurably varying family of dyadic

A_p

weights. This averaging process is suggested by the relationship between the

A_p

weight class and the space of functions of bounded mean oscillation. The same averaging process also constructs weights satisfying reverse Hölder (

RH_p

) conditions from families of dyadic

RH_p

weights, and extends to the polydisc as well.
Closed ideals of $A^\infty$ and a famous problem of Grothendieck
Authors: Patel S. R.
Published: December 2011

Using Fréchet algebraic technique, we show the existence of a nuclear Fréchet space without basis, thus providing yet another proof (of a different flavor) of a negative answer to a well known problem of Grothendieck from 1955. Using Fefferman's construction (which is based on complex-variable technique) of a

C^\infty

-function on the unit circle with certain properties, we give much simpler, transparent, and "natural" examples of restriction spaces without bases of nuclear Fréchet spaces of

C^\infty

-functions; these latter spaces, being classical objects of study, have attracted some attention because of their relevance to the theories of PDE and complex dynamical systems, and harmonic analysis. In particular, the restriction space

A^\infty(E)

, being a quotient algebra of the algebra

A^\infty(\Gamma)

, is the central one to other examples; the algebras

A^\infty

had played a crucial role in solving a well-known problem of Kahane and Katznelson in the negative.
$L^p$ improving multilinear Radon-like transforms
Authors: Stovall Betsy
Published: December 2011

e characterize (up to endpoints) the

k

-tuples

(p_1,\ldots,p_k)

for which certain

k

-linear generalized Radon transforms map the product

L^{p_1} \times \cdots \times L^{p_k}

boundedly into

\mathbb{R}

. This generalizes a result of Tao and Wright.
Fossil versus contemporary sources of fine elemental and organic carbonaceous particulate matter during the DAURE campaign in Northeast Spain
Authors: Minguillón M. C. , Perron N. , Querol X. , Szidat S. , Fahrni S. M. , Alastuey A. , Jimenez J. L. , Mohr C. , Ortega A. M. , Day D. A. , Lanz V. A. , Wacker L. , Reche C. , Cusack M. , Amato F. , Kiss G. , Hoffer A. , Decesari S. , Moretti F. , Hillamo R. , Teinilä K. , Seco R. , Peñuelas J. , Metzger A. , Schallhart S. , Müller M. , Hansel A. , Burkhart J. F. , Baltensperger U. , Prévôt A. S. H.
Published: December 2011

Abstract. We present results from the international field campaign DAURE (Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the Western Mediterranean), with the objective of apportioning the sources of fine carbonaceous aerosols. Submicron fine particulate matter (PM1) samples were collected during February–March 2009 and July 2009 at an urban background site in Barcelona (BCN) and at a forested regional background site in Montseny (MSY). We present radiocarbon (14C) analysis for elemental and organic carbon (EC and OC) and source apportionment for these data. We combine the results with those from component analysis of aerosol mass spectrometer (AMS) measurements, and compare to levoglucosan-based estimates of biomass burning OC, source apportionment of filter data with inorganic composition + EC + OC, submicron bulk potassium (K) concentrations, and gaseous acetonitrile concentrations. At BCN, 87 % and 91 % of the EC on average, in winter and summer, respectively, had a fossil origin, whereas at MSY these fractions were 66 % and 79 %. The contribution of fossil sources to organic carbon (OC) at BCN was 40 % and 48 %, in winter and summer, respectively, and 31 % and 25 % at MSY. The combination of results obtained using the 14C technique, AMS data, and the correlations between fossil OC and fossil EC imply that the fossil OC at Barcelona is ∼47 % primary whereas at MSY the fossil OC is mainly secondary (∼85 %). Day-to-day variation in total carbonaceous aerosol loading and the relative contributions of different sources predominantly depended on the meteorological transport conditions. The estimated biogenic secondary OC at MSY only increased by ∼40 % compared to the order-of-magnitude increase observed for biogenic volatile organic compounds (VOCs) between winter and summer, which highlights the uncertainties in the estimation of that component. Biomass burning contributions estimated using the 14C technique ranged from similar to slightly higher than when estimated using other techniques, and the different estimations were highly or moderately correlated. Differences can be explained by the contribution of secondary organic matter (not included in the primary biomass burning source estimates), and/or by an overestimation of the biomass burning OC contribution by the 14C technique if the estimated biomass burning EC/OC ratio used for the calculations is too high for this region. Acetonitrile concentrations correlate well with the biomass burning EC determined by 14C. K is a noisy tracer for biomass burning.
Estimating the climate significance of halogen-driven ozone loss in the tropical marine troposphere
Authors: Saiz-Lopez A. , Lamarque J.-F. , Kinnison D. E. , Tilmes S. , Ordóñez C. , Orlando J. J. , Conley A. J. , Plane J. M. C. , Mahajan A. S. , Sousa Santos G. , Atlas E. L. , Blake D. R. , Sander S. P. , Schauffler S. , Thompson A. M. , Brasseur G.
Published: December 2011

Abstract. We have integrated observations of tropospheric ozone, very short-lived (VSL) halocarbons and reactive iodine and bromine species from a wide variety of tropical data sources with the global CAM-Chem chemistry-climate model and offline radiative transfer calculations to compute the contribution of halogen chemistry to ozone loss and associated radiative impact in the tropical marine troposphere. The inclusion of tropospheric halogen chemistry in CAM-Chem leads to an annually averaged depletion of around 10% (~2.5 Dobson units) of the tropical tropospheric ozone column, with largest effects in the middle to upper troposphere.This depletion contributes approximately −0.10 W m−2 to the radiative flux at the tropical tropopause. This negative flux is of similar magnitude to the ~0.33 W m−2 contribution of tropospheric ozone to present-day radiative balance as recently estimated from satellite observations. We find that the implementation of oceanic halogen sources and chemistry in climate models is an important component of the natural background ozone budget and we suggest that it needs to be considered when estimating both preindustrial ozone baseline levels and long term changes in tropospheric ozone.
Role of land surface processes and diffuse/direct radiation partitioning in simulating the European climate
Authors: Davin E. L. , Seneviratne S. I.
Published: December 2011

Abstract. The influence of land processes and in particular of diffuse/direct radiation partitioning on surface fluxes and associated regional-scale climate feedbacks is investigated. ERA-40 driven simulations over Europe are performed using the COSMO-CLM2 Regional Climate Model (RCM). Two alternative Land Surface Models (LSMs), a 2nd generation LSM (TERRA_ML) and a more advanced 3rd generation LSM (Community Land Model version 3.5), and two versions of the atmospheric component are tested, as well as a revised coupling procedure allowing for variations in diffuse/direct light partitioning at the surface, and their accounting by the land surface component. Overall, the RCM performance for various variables (e.g., surface fluxes, temperature and precipitation) is improved when using the more advanced 3rd generation LSM. These improvements are of the same order of magnitude as those arising from a new version of the atmospheric component, demonstrating the benefit of using a realistic representation of land surface processes for regional climate simulations. Taking into account variability in diffuse/direct light partitioning at the surface further improves the model performance in terms of summer temperature variability at the monthly and daily time scales. Comparisons with observations show that the RCM realistically captures temporal variations in diffuse/direct light partitioning as well as the evapotranspiration sensitivity to these variations. Our results suggest that a modest but consistent fraction (up to 3 %) of the overall variability in summer temperature can be explained by variations in the diffuse to direct ratio.
Rolling stones; fast weathering of olivine in shallow seas for cost-effective CO2 capture and mitigation of global warming and ocean acidification
Authors: Schuiling R. D. , de Boer P. L.
Published: December 2011

Abstract. Human CO2 emissions may drive the Earth into a next greenhouse state. They can be mitigated by accelerating weathering of natural rock under the uptake of CO2. We disprove the paradigm that olivine weathering in nature would be a slow process, and show that it is not needed to mill olivine to very fine, 10 μm-size grains in order to arrive at a complete dissolution within 1–2 year. In high-energy shallow marine environments olivine grains and reaction products on the grain surfaces, that otherwise would greatly retard the reaction, are abraded so that the chemical reaction is much accelerated. When kept in motion even large olivine grains rubbing and bumping against each other quickly produce fine clay- and silt-sized olivine particles that show a fast chemical reaction. Spreading of olivine in the world's 2% most energetic shelf seas can compensate a year's global CO2 emissions and counteract ocean acidification against a price well below that of carbon credits.
Analysis of predicted and observed accumulated convective precipitation in the area with frequent split storms
Authors: Ćurić M. , Janc D.
Published: December 2011

Abstract. Convective clouds generate extreme rainfall events and flash floods in small areas with both large spatial and temporal variability. For this reason, the monitoring of the total accumulated precipitation fields at the surface with rain gauges and meteorological radars has both strengths and weakness. Alternatively, a numerical cloud model may be a useful tool to simulate convective precipitation for various analyses and predictions. The main objective of this paper is to show that the cloud-resolving model reproduces well the accumulated convective precipitation obtained from the rain gauge network data in the area with frequent split storms. We perform comparisons between observations and model samples of the areal accumulated convective precipitation for a 15-year period over treated area. Twenty-seven convective events have been selected. Statistical analyses reveal that the model areal accumulated convective precipitation closely match their observed values with a correlation coefficient of 0.80.
Diurnal Variation of the Tear Osmolarity in Normal Subjects Measured by a New Microchip System
Authors: Oncel Banu Açikalin , Pinarci Eylem , Akova Yonca A.
Published: December 2011

Purpose

To show the diurnal variation of tear osmolarity in normal subjects.

Methods

Thirty volunteers were recruited. Tear osmolarity was measured with TearLab osmolarity system at 3-hour regular intervals between 8:00 AM and 5:00 PM. One-way analysis of variance test was used for statistical analysis.

Results

Thirty healthy volunteers (all men) with a mean age of 29.6±4.3 years (range 18-45) were recruited. The difference between measurements at 8:00 AM and 11:00 AM, 8:00 AM and 2:00 PM, 8:00 AM and 5:00 PM, 11:00 AM and 2:00 PM, 11:00 AM and 5:00 PM, and 2:00 PM and 5:00 PM were not statistically significant (one-way analysis of variance test, p>0.05).

Conclusions

In normal subjects, tear osmolarity seems to have a stable profile during the daytime.
Application of 10% Povidone Iodine Reduces Conjunctival Bacterial Contamination Rate in Patients Undergoing Cataract Surgery
Authors: Nentwich Martin M. , Rajab Mohammed , Ta Christopher N. , He Lisa , Grueterich Martin , Haritoglou Christos , Gandorfer Arnd , Kampik Anselm , De Kaspar Herminia Mino
Published: December 2011

Purpose

To determine the efficacy of 10% povidone iodine (PVI) drops given before cataract extraction in addition to routine irrigation of the conjunctival sac with 1% PVI.

Methods

This prospective, randomized, single-center study at the Department of Ophthalmology, Ludwig-Maximilians-University, Munich, includes 263 eyes of 242 patients undergoing cataract surgery. Patients were randomized to receive 3 drops of 10% PVI into the conjunctival sac (study group) or no PVI drops (control group). All patients underwent periorbital disinfection with 10% PVI followed by irrigation of the conjunctiva with 10 mL of 1% PVI. Specimens were obtained prior to the application of PVI, after antibiotic administration (T1), after irrigation with PVI but before surgery (T2), and at the conclusion of surgery (T3).

Results

After PVI disinfection, the number of positive cultures was significantly reduced in all groups (p<0.0001) from 69%-93% at T1 to 1%-16% at T3. In outpatients, the study group showed significantly fewer positive cultures at the conclusion of surgery compared to the control group (4% vs 16%; p=0.03). Also in inpatients significant fewer positive cultures were found in the study group compared to the control group at T2 (12% vs 28%; p=0.03) and at T3 (1% vs 10%; p=0.03).

Conclusions

Three additional drops of 10% PVI prior to surgery provided additional benefit by reducing the conjunctival bacterial contamination rate even in the setting of preoperative irrigation of the conjunctiva with 1% PVI.
Evaluation of In-Season Nitrogen Management for Summer Maize in North Central China
Authors: Zhao S.-C. , He P. , Sha Z.-M. , Xing S.-L. , Li K.-J.
Published: December 2011

We conducted field experiments in which nitrogen (N) was applied to summer maize at different rates and different basal/topdressing ratios. The experiments were carried out in 2009 in Hengshui and Xinji, Hebei province, China. The results showed that basal application of N was necessary for maize growth in early summer and for high grain yields. For the Hengshui and Xinji sites, 30 and 57 kg N ha−1, respectively, would meet the N demands of maize before 7-leaf stage. The total rates of 120 and 180 kg N ha−1, respectively, would maximize grain yields, and in-season N management based on crop N demands and soil N supply could reduce N inputs by more than 50% in Hengshui and 25% in Xinji, respectively, in one maize growth season, compared with farmers' practice, but the sustainability of the optimum N rates for maximum grain yield of next seasons crop needs to be further studied. Optimum N management should take into account the existing nutrient conditions at each site, soil fertility and texture, and crop demands.
Comparison Theorems for the Position-Dependent Mass Schrödinger Equation
Authors: Kulikov D. A.
Published: December 2011

The following comparison rules for the discrete spectrum of the position-dependent mass
(PDM) Schrödinger equation are established. (i) If a constant mass m0 and a PDM m(x) are ordered everywhere, that is either, m0≤m(x) or m0≥m(x), then the corresponding eigenvalues of the constant-mass Hamiltonian and of the PDM Hamiltonian with the same potential and the BenDaniel-Duke ambiguity parameters are ordered. (ii) The corresponding eigenvalues of PDM Hamiltonians with the different sets of ambiguity parameters are ordered if ∇2(1/m(x)) has a definite sign. We prove these statements by using the Hellmann-Feynman theorem and offer examples of their application.
Stress Induced Nitrogen Diffusion in Nitrided Austenitic Stainless Steel
Authors: MOSKALIOVIENĖ Teresa , GALDIKAS Arvaidas
Published: December 2011

The nitrogen transport mechanism in plasma nitrided austenitic stainless steel at moderate temperatures (around 400 °C) is explained by non-Fickian diffusion model. The model considers the diffusion of nitrogen in presence of internal stresses gradient induced by penetrating nitrogen as the next driving force of diffusion after concentration gradient. For mathematical description of stress induced diffusion process the equation of barodiffusion is used, which involves concentration dependant barodiffusion coefficient. For calculation of stress gradient it is assumed that stress depth profile linearly relates with the nitrogen concentration depth profile. The calculated nitrogen depth profiles in an austenitic stainless steel are in good agreement with experimental nitrogen profiles. The diffusion coefficient D = 1.68-10 -12 cm2/s for nitrogen in a plasma source ion nitrided 1Cr18Ni9Ti (18-8 type) austenitic stainless steel at 380 °C was found from fitting of experimental data. It is shown that nitrogen penetration depth and nitrogen surface concentration increases with nitriding temperature nonlinearly.http://dx.doi.org/10.5755/j01.ms.17.1.241
Resistance of Chromated Zinc Coatings to the Impact of Microscopic Fungi
Authors: LUGAUSKAS Albinas , DEMČENKO Irina , SELSKIENĖ Aušra , PAKŠTAS Vidas , JASKELEVIČIUS Bronius , NARKEVIČIUS Algirdas , BUČINSKIENĖ Dalia
Published: December 2011

Zinc coatings are used to protect metallic parts of automobiles from corrosion. Zinc protective coatings are often chromated additionally treating them in acidic solution of chromium compounds. In recent years new technologies were designed to deposit chromate films of various thickness and resistance on zinc surface from acidic solution of Cr(III) compounds. It has been noticed, that under atmospheric corrosion conditions microscopic fungi are present in the environment affect zinc coating. The aim of the presented study was to determine if zinc coatings treated with Cr(III) solution become more resistant to fungi influence or their resistance diminishes. The analysis of steel plates coated with a zinc film and treated in four different chromium solutions has shown that in all the specimens fungi of Cladosporium herbarium species were detected and their frequency of detection was quite high, sometimes up to 50 %. However, we failed to determine the regularities of distribution of some fungi on the surface of plates chromated in different solution. The comparison of changes in the surfaces of plates treated with the four solutions has shown that the plates treated in the Likonda 3Cr5 passivation solution changed least after being exposed to atmospheric conditions. Chromated plates contaminated with mixtures of different fungi and kept for 60 days at a temperature of (26 ±2) °C under humid conditions were examined by using a scanning electron microscope (EVO 5O XP Carl Zeiss STM AG, Germany) and the peculiarities of their surface damage were determined. The peculiarities of growth of some fungi species were determined on the plates chromated in the Likonda 3Cr5 and Cr(NO3)3*9H2O + malonic acid solutions. Under these conditions the fungi of Chrysosporium merdarium, Fusarium proliferatum, Paecilomyces lilacinus, Penicillium stoloniferum can either generate and promote the damage of metal surface or stabilize its corrosion processes.http://dx.doi.org/10.5755/j01.ms.17.1.243
Rheological and Mechanical Properties of Poly(lactic) Acid/Cellulose and LDPE/Cellulose Composites
Authors: SHUMIGIN Dmitri , TARASOVA Elvira , KRUMME Andres , MEIER Pille
Published: December 2011

In our work we studied composites of poly(lactic) acid (PLA) and low density polyethylene filled with cellulose fibres. The studied composite materials were manufactured with a twin-screw extruder. The extruded compound was processed in to samples using compression moulding. The content of cellulose in polymer/cellulose composites was varied. Effect of low amounts of cellulose on the rheological and tensile properties was studied. Tensile tests showed that the incorporation of cellulose into PLA matrix lead to stiffer but slightly more brittle and weaker materials, since Young's modulus increases and tensile strength and elongation at break slightly decrease. Mechanical results are in agreement with rheological behaviour: the composites exhibit the improvement in the storage and loss moduli of composites compared with that of matrix polymers. The composite dynamic viscosity increases with cellulose content in the same manner as loss and storage moduli. The processing and material properties of PLA/cellulose composites were compared to the more commonly used low-density-polyethylene/cellulose composites.http://dx.doi.org/10.5755/j01.ms.17.1.245
Modification of Textile Materials' Surface Properties Using Chemical Softener
Authors: KOŽENIAUSKIENĖ Jurgita , DAUKANTIENĖ Virginija
Published: December 2011

In the present study the effect of technological treatment involving the processes of washing or washing and softening with chemical cationic softener "Surcase" produced in Great Britain on the surface properties of cellulosic textile materials manufactured from cotton, bamboo and viscose spun yarns was investigated. The changes in textile materials surface properties were evaluated using KTU-Griff-Tester device and FEI Quanta 200 FEG scanning electron microscope (SEM). It was observed that the worst hand properties and the higher surface roughness are observed of cotton materials if compared with those of bamboo and viscose materials. Also, it was shown that depending on the material structure the handle parameters of knitted materials are the better than the ones of woven fabrics.http://dx.doi.org/10.5755/j01.ms.17.1.249
A Facile Method for Low-Temperature Synthesis of NaV₃O₈ as Cathode Materials for Lithium Secondary Batteries
Authors: YUAN Chao , LI Cong , MA Binqiang , LI Xin , CAO Xiaoyu
Published: December 2011

A facile method has been used to synthesize NaV3O8 powders with oxalic acid as the complexing agent. This soft-synthesis technique can effectively reduce the calcination temperature for synthesizing NaV3O8 powders to 300 °C, which is much lower than that in the solid-state synthesis. The thus-synthesized NaV3O8 powders are characterized by XRD, SEM and galvanostatic charge-discharge test. Among the as-prepared powders, the NaV3O8 powder obtained at 350 °C exhibits morphology of porous particles. The electrochemical analysis reveals that this powder demonstrates high discharge capacity and good cycleability.http://dx.doi.org/10.5755/j01.ms.17.1.252
Effect of Fibre and Microsilica Incorporation on High Temperature Resistance of Cementitious Complex Binder
Authors: KALPOKAITĖ-DIČKUVIENĖ Regina , BRINKIENĖ Kristina , ČĖSNIENĖ Jūratė , MAKŠTYS Algis
Published: December 2011

Complex binder reinforced with microfibre produced from waste catalyst was investigated. Influence of 1, 3 and 5 % of fibre as well as 5 % of microsilica on the mechanical strength of complex binder after thermal treatment at 600, 800 and 1000 °C temperature was analyzed. According to the experimental results reinforcement with 1 % of fibre had advantage on mechanical strength of complex binder up to 800 °C, meanwhile 5 % of fibre resulted in the lowest values of strength in all firing temperature range. The strength of dry samples was improved with microsilica incorporation. But above 800 °C temperature cold crushing strength as well as thermal shrinkage of binder reinforced with fibre and microsilica was lower in comparison with ordinary complex binder at 1000 °C.http://dx.doi.org/10.5755/j01.ms.17.1.253
Fire Resistance Tests of Various Fire Protective Coatings
Authors: GRIGONIS Mindaugas , MAČIULAITIS Romualdas , LIPINSKAS Donatas
Published: December 2011

Tests were carried out on more than 14 different samples of fire protective coatings in order to investigate a relation between the thickness of the intumescent fire protection coating and the time of exposure to heat. A number of coatings of different chemical composition enabled to determine the fire resistance behaviour patterns. During test the one-side and volumetric methods were employed in observance of the standard temperature-time curves. For one-side method, the coating was applied on one side and all edges of the specimen, whereas for volumetric test the specimens were completely covered with fire protective coating. It is shown that a layer of coating protects the specimen's surface from heat exposure for a certain period of time until full oxidation of the coating occurs. The efficiency of fire protective coatings also depends on thickness of the charred layer of the side exposed to heat.http://dx.doi.org/10.5755/j01.ms.17.1.257
The Study of Corrosion and Wear Resistance of Copper Composite Coatings with Inclusions of Carbon Nanomaterials in the Copper Metal Matrix
Authors: MEDELIENĖ Viktorija , STANKEVIČ Vojtech , GRIGUCEVIČIENĖ Asta , SELSKIENĖ Aušra , BIKULČIUS Gedvidas
Published: December 2011

This paper deals with the peculiarities of the behaviour of copper nanocomposite coatings with CNMs inclusions under the free corrosion conditions in the acidic medium. The parameters of corrosion current density (jcorr), anodic dissolution current density (ia) and polarization resistance (Rp) have been determined. In the acidic medium a stronger oxidation of nanostructured copper nanocomposites occurred. With longer immersion periods more corrosion products are formed, resulting in a increase in the polarization resistance (Rp) of corrosion. Corrosion products cover the whole surface of the coatings and the corrosion rate (jcorr) tends towards a steady value of 1.7×10-3 ¸ 2.1×10-3 A·cm-2 for all copper coatings studied: 1.7×10-3 A·cm-2 for both Cu and Cu-CNM1, 1.9×10-3 A·cm-2 - for Cu-CNM2 and 2.1×10-3 A·cm-2 - for Cu-CNM3 composite coatings. It has been established that nanocomposites possess a higher wear resistance as compared to that of pure copper. The damage of metal characterized as a depth scar (đ) is lower. The roughness of the composites studied was found to be the essential factor affecting their wear resistance. Therefore, the wear resistance of nanocomposites is impaired when they are deposited on a hard steel substrate.http://dx.doi.org/10.5755/j01.ms.17.2.481