bluuebunny/crossref_metadata_2025 huggingface dataset:
Zur lokalen Lösbarkeit nichtlinearer Differentialgleichungen vom gemischten Typ
Authors: Günther Matthias
Published: December 2016

We show the existence of solutions for two classes of nonlinear second order differential equations of mixed type in a neighbourhood of some point. The proof is based on a modification of Galerkin’s method and works with three Banach spaces. We get the necessary coercivity inequality from suitable nonlinear energy estimates.
Langzeitverhalten einer parabolischen Evolutionsgleichung mit zufälligen Einflüssen
Authors: Schmalfuss Björn
Published: December 2016

The convergence of solution distributions of the statistical Navier-Stokes equation to a compact set of distributions is shown. Moreover, properties of this set are observed.
On the Existence of Solutions of a Semilinear Elliptic Boundary Value Problem with Superlinear Nonlinearities
Authors: Drábek Pavel , Runst Thomas
Published: December 2016

We study the solvability of a semi linear elliptic boundary value problem with superlinear nonlinearity in spaces of Besov and Triebel-Lizorkin type.
Bifurcation and Stability of Capillary-Gravity Waves
Authors: Quasthoff Karin
Published: December 2016

Tlree-dimensional capillary-gravity waves of a fluid of finite depth are considered. The fluid moves stationary over a plane bottom. For smallest critical Froude numbers there is a two- dimensional wave bifurcating from the trivial surface configuration.
Explizite Lösungen einer Klasse nichtlinearer partieller Differentialgleichungen
Authors: Herold Horst
Published: December 2016

For a class of nonlinear partial differential equations comprising the equation of Boussinesq the complete solution of an initial value problem is given in explicit form by means of the Weierstrass

p

-function.
Perturbation of Temperature Fields by a Small Inclusion
Authors: Göhde Dietrich
Published: December 2016

In a domain which contains a small subdomain

\Omega_{\epsilon}

a boundary value problem of second order with transition conditions on the boundary of

\Omega_{\epsilon}

is posed. For its solution an asymptotic expansion is constructed with respect to the diameter of

\Omega_{\epsilon}

tending to zero.
Travelling Wave Solutions of a Nonlinear Diffusion Equation with Integral Term
Authors: von Wolfersdorf Lothar
Published: December 2016

Travelling wave solutions with compact support are investigated for a class of nonlinear nonlocal degenerate diffusion equations introduced by T. Nagai and M. Mimura. The problem is reduced to a boundary value problem for an integro-differential equation of second order and in turn to an integral equation with nonnegative kernel. There are given existene proofs for three types of power nonlinearities in case of a general integral term and closed solutions for a simple integral term.
On the Global Solvability of the Diffusion Equation of Satsuma and Mimura
Authors: Wegert Elias
Published: December 2016

A conjecture of Satsuma and Mimura concerning blow-up effects of solutions of a nonlinear diffusion equation is proved.
Asymptotische Entwicklungen der konfluenten hypergeometrischen Funktionen $U(a, b, z)$ und $M (a, b, z)$ für große Werte von $b$ und $z$
Authors: Schell Hans-Joachim
Published: December 2016

Asymptotic expansions are derived for the confluent hypergeometric functions

U (a, b, z)

and

M(a, b, z)

, holding for large real values of

b

and

z = yb (a > 0, y > 0

, fixed). The cases

y < 1

and

y > 1

are investigated. The results include the asymptotic expansions für

b \to \infty

,

z

fixed, and the well-known expansions when

z \to \infty

,

b

fixed.
Zur Konvergenzbeschleunigung von Reihen mit logarithmischer Konvergenz
Authors: Riedel Roland
Published: December 2016

Asymptotic expansions for the residual sums of series are derived in the case of logarithmical convergence. Finite parts of this expansions are used for the acceleration of convergence.
On the Interior Regularity of Weak Solutions to Nonlinear Elliptic Systems of Second Order
Authors: Daněček Josef
Published: December 2016

The interior

C^{1, \alpha}

-regularity for a weak solution (with gradient in the BMO-space) of a non-linear second order elliptic system is investigated. The positive answer is obtained on the assumption that the elliptic system satisfy the generalized Liouville condition considered in the BMO-space instead of the usually used

L^{\infty}

-space. Finally it is proved that the Liouville condition holds in the case of

\mathbb R^2

.
On the representation of Bergman–Vekua-operators for three-dimensional equations
Authors: Lanckau Eberhard
Published: December 2016

The integral operators of S. Bergman and I. N. Vekua transform holomorphic functions of a complex variable into solutions of linear partial differential equations of elliptic type in the plane. Generalizing these methods we find integral transforms for the solution of partial differential equations of various type (e.g. parabolic, elliptic, pseudoparabolic) with three independent variables. The transforms associate holomorphic functions of two variables and the mentioned solution. We give (for an example) an explicit representation of the kernel of these transforms (by a sum of a Duhamel product and Cauchy integrals) which generalizes recent results of D. L. Colton and R. P. Gilbert.
On the Cauchy Problem for Quasilinear Hyperbolic Systems of Partial Differential-Functional Equations of the First Order
Authors: Człapiński Tomasz
Published: December 2016

An existence and uniqueness theorem for the generalized solution (in the "almost everywhere" sense) of the Cauchy problem for a quasilinear functional partial differential system of the first order is proved.
Accelerating Convergence of Univariate and Bivariate Fourier Approximations
Authors: Tasche Manfred
Published: December 2016

Some new results concerning the accelerating convergence of univarlate and bivariate Fourier expansions are presented. The rate of convergence is estimated with respect to the uniform norm.This acceleration method is a combination of algebraic and trigonometric approximation. Note that the abstract Taylor formula is an essential tool of this approach.
Travelling Wave Solutions of a System of Nonlinear Diffusion Equations with Integral Term
Authors: Knabner Peter , von Wolfersdorf Lothar
Published: December 2016

The existence of travelling wave solutions with compact support is shown for a system of nonlinear non-local degenerate diffusion equations of population dynamics. Besides the behaviour of an important class of particular solutions of this type is investigated analytically and numerically.
Über eine Veraligemeinerung der Legendre-Hadamardschen Bedingung auf restringierte Variationsprobleme
Authors: Klötzler Rolf
Published: December 2016

Variational problems are studied with continuous integrand, subject to vector-valued functions

x

of vector variables

t

with restricted derivatives

x_t

under some goodness conditions of their feasible set

X

. For an optimal solution

x_o

it will be shown the necessity of the (strong) quasi-convexity (in the sense of C. B. Morrey) of the integrand on

X

in regard of

x_o

.
A Fully Discrete Approximation Method for the Exterior Neumann Problem of the Helmholtz Equation
Authors: Prössdorf Siegfried , Saranen J.-J.
Published: December 2016

Considering an exterior domain with smooth closed boundary curve we introduce a fully discrete scheme for the solution of the acoustic boundary value problem of the Neumann type. We use a boundary integral formulation of the problem which leads to a hypersingular boundary integral equation. Our discretization scheme for the latter equation can be con-sidered as a discrete version of the trigonometric collocation method and has arbitrarily high convergence rate, even exponential if the solution and the curve are analytic.
Chebyshev Polynomial Iterations and Approximate Solutions of Linear Operator Equations
Authors: Zabrejko A.P. , Zabrejko Petr P.
Published: December 2016

An iteration scheme for the approximate solution of a linear operator equation in a Banach space is discussed from the viewpoint of Chebyshev polynomials. The optimal rate of convergence is described by numerical characteristics which are similar to (but different from) the classical Chebyshev constants. The abstract results are illustrated by some examples which frequently arise in applications.
The Smoothness of Solutions to Nonlinear Weakly Singular Integral Equations
Authors: Pedas Arvet , Vainikko Gennadi
Published: December 2016

The differential properties of a solution of a nonlinear multidimensional weakly singular integral equation of the Uryson type on an open bounded set

G \in \mathbb R^n

are examined. Showing that the solution belongs to special weighted space of smooth functions, the growth of the derivatives near the boundary is described.
On Fundamental Solutions of the Heat Conduction Difference Operator
Authors: Gürlebeck Klaus , Hommel A.
Published: December 2016

is the aim of the paper to investigate fundamental solutions for the difference operator of heat conduction in the explicit and also in the implicit case. The existence of fundamental solutions will be shown in a constructive way. In both cases the convergence of the discrete fundamental solutions to the continuous fundamental solution will be investigated in the discrete

l_1

-space.
On the Oscillatory Behaviour of Solutions of Second Order Nonlinear Difference Equations
Authors: Thandapani E. , Pandian S.
Published: December 2016

By using simple discrete inqualities sufficient conditions are provided for the solution {

y_n

} of a difference equation of the form

\Delta(a_n \Delta y_n) + q_{n+1} f (y_{n+1} = r_n (n \in \mathbb N_0; {a_n}, {q_n}, {r_n} C \mathbb R; f : \mathbb R \to \mathbb R)

to be oscillatory or to satisfy lim inf

_{n \to \infty} |y_n| = 0

. Also two other results are established for all solutions of this equation to be oscillatory when

r_n = 0

for all

n \in \mathbb N_0

.
A Note on the Invertibility of Generalized Wiener–Hopf Operators
Authors: Donig Jörg
Published: December 2016

We consider generalized Wiener–Hopf-operators of the form

T(A) := PA \uparrow R(P)

in a Hilbert space, where

A

and

P

are linear, bounded operators, and

P

permits a Moore–Penrose inverse. The purpose of our investigations is to derive a criterion for the invertibility of

T(A)

in

R(P)

.
On the Nakano Individual Convergence
Authors: Zaharopol R.
Published: December 2016

We have recently defined the notion of individual convergence for a sequence of positive elements of an Archimedean Riesz space

E

. In the note we complete the definition (i.e., we define the individual convergence for sequences of not necessarily positive elements of

E

), and we prove that our notion of individual convergence is a natural extension of the individual convergence as defined by Nakano: we will prove that if a sequence of elements of

E

has an individual limit in the Nakano sense, then it converges individually with respect to our definition.
General Random Sum Limit Theorems for Martingales with large $\mathcal O$-Rates
Authors: Butzer Paul  L. , Schulz D.
Published: December 2016

This paper is concerned with large

\mathcal O

error estimates for convergence in distribution of random sums of not necessarily independent random variables. As applications of a general theorem one obtains the random-sum versions of the central limit theorem and of the weak law of large numbers for martingale difference sequences by specializing the limiting random variable. Both theorems are equipped with

\mathcal O

-rates.
Tangential Carathéodory-Fejer Interpolation for Stieltjes Functions at Real Points
Authors: Bolotnikov Vladimir
Published: December 2016

In this paper we consider a generalization of the classical interpolation problem in a special class of analytic matrix-valued functions. The method used to solve this problem is that of the fundamental matrix inequality, suitably adapted to the present situation.
Behaviour of Solutions of a Third Order Differential Equation
Authors: Greguš M. , Sišoláková D.
Published: December 2016

Properties of proper and regular non-oscillatory solutions of the equation

x"' + f(t)g(x, x’, x") = 0

, and some sufficient conditions for regular solutions to be oscillatory or non-oscillatory are derived.
A Class of One-Dimensional Variational Inequalities and Difference Schemes of Arbitrary Given Degree of Accuracy
Authors: Gavrilyuk I.P.
Published: December 2016

A new class of one-dimensional variational inequalities with obstruction on the boundary is investigated and a theorem of existence and uniqueness of solution is proved. The investigated properties of the exact solution give an opportunity to construct the three -point difference relations for this solution (exact difference scheme). A numerical three-point approximation of arbitrary given degree of accuracy (truncated difference scheme) is proposed.
A Higher Order Uniform Convergence Result for a Turning Point Problem
Authors: Roos H.-G. , Vulanović R.
Published: December 2016

We describe a new fitted scheme, of

k

-th order uniform accuracy with arbitrary

k

, for a turning point problem of cusp type. The scheme is constructed by applying an iterative technique to an auxiliary problem obtained after replacing coefficient functions in the original problem by piecewise polynomials. The analysis of the scheme is based on an improved stability result.
Sequence Spaces and Stability of Integer Translates
Authors: Sun Qiyu
Published: December 2016

In this paper, we introduce sequence spaces of Triebel-Lizorkin type, especially Hardy spaces and bounded mean oscillation spaces. We establish

F^{\alpha q}_p

-stability of integer translates of general distributions which extends the results of [7,8] to general distributions. Also the corresponding David-Journé theorem for sequences is established.
Existence Theorems and Measurement of the Capillary Contact Angle
Authors: Fischer B.S. , Finn Robert
Published: December 2016

In an earlier work, Concus and Finn proposed two procedures, based on a dichotomous, behavior of fluid in capillary tubes at zero gravity, designed for-accurate measurement of capillary contact angles. The present work offers modifications to one of their procedures which should facilitate the experiments and lead to improved accuracy. The discussion leads to explicit characterization of a capillary tube with "canonical" section, which has an independent mathematical interest.
The Smoothness of the Solution to a Two-Dimensional Integral Equation with Logarithmic Kernel
Authors: Kangro U.
Published: December 2016

We observe a two-dimensional weakly singular integral equation with logarithmic kernel. The behavior of the higher order derivatives of the solution to the equation is examined in case of bounded domain of Integration with piecewise smooth boundary. Exact descriptions for the leading terms of the derivatives and estimations for the remainders are given.
Interdependent Components of Generating Systems in the Theory of Pseudo-Holomorphic Functions
Authors: Withalm C.
Published: December 2016

In many studies concerning the theory of pseudo-holomorphic functions in the sense of L. Bers the interdependence of the components of a relevant generating system turns out to be essential to investigate, e.g. inquiring into periodicity problems with respect to corresponding derivatives but also into multiple reasonable configurations.
An Existence Theorem for Control Problems with Unbounded Control Domain
Authors: Kraut H.
Published: December 2016

Control problems of Dieudonné-Rashevsky type for multiple integrals, generalized in the sense of E.J. McShane and L. C. Young, are considered. For the case of unbounded control domains an existence theorem for optimal generalized processes is proved.
Continuous Dependence Results for Subdifferential Inclusions
Authors: Papageorgiou Nikolaos S.
Published: December 2016

In this paper we examine the dependence on a parameter of the solution set of a class of nonlinear evolution inclusions driven by subdifferential operators. We prove that under mild hypotheses on the data, the solution set depends continuously on the parameter for both the Victoria and Rausdorif topologies. Then we use these results to study the variational stability of the class of semnilinear parabolic optimal control problems and we also indicate how our work incorporates the stability analysis of differential variational inequalities.
Norms of Best Smoothness in Orlicz Spaces
Authors: Maleev R.P.
Published: December 2016

Equivalent norms of best smoothness are constructed for large classes of Orlicz sequence and function spaces.
Normabschätzungen für die Inversen von Toeplitz-Matrizen
Authors: Pomp Andreas
Published: December 2016

For discrete and paired discrete Wiener-Hopf equations of normal type, the symbol of which possesses a quadratic summable first derivative, we estimate the constants arising in error estimates for the reduction method.
On Some Completion Problems for Various Subclasses of $j_{pq}$-inner Functions
Authors: Arov D.Z. , Fritzsche B. , Kirstein B.
Published: December 2016

Several completion problems of the following type will be studied: Given meromorphic matrix-valued functions

f

and

h

, the question is to describe the set of all

j_{pq}

-inner functions

W

which have the block structure

W = (^{*f}_{*h}9

.
Products of Distributions in Several Variables and Applications to Zero–Mass QED$_2$
Authors: Embacher Hans G. , Grübl Gebhard , Oberguggenberger Michael
Published: December 2016

We study products of distributions in several variables, having in mind applications to quantum electrodynamics. We introduce a new product, the parameter product, and relate it to known ones. It allows us to rigorously interpret and evaluate products arising in the computations of the one-loop vacuum polarization of zero-mass QED

_2

, thereby avoiding the occurrence of renormalization ambiguities from the very beginning.
Mixed Contact Problems in Plane Elasticity
Authors: Maul Johannes
Published: December 2016

The paper is concerned with the contact problem of the isotropic elastic plane with a simply connected elastic inclusion of different material in the frame of elastostatics. The contact curve is dissected into 9 pairwise disjoint curve systems, at which 9 different contact conditions are prescribed. Some regularity concepts are defined (so-called *-regularity,

\epsilon

*-regularity and

\epsilon

-regularity), which imply certain restrictions for the contact data, for instance certain compatibility conditions. Using Green formulas, the problem of uniqueness is studied and, in certain cases, some necessary conditions are given. By the aid of elastic potential of single layer, a system of integral equations is obtained, containing two arbitrary constants on the right-hand side. The solution

\Phi

to be determined is subjected to an additional integral relation. By application of a suitable differential operator

\Omega_p

, a system, of singular integral equations with discontinuous coefficients is obtained. The dimension of the linear space ker

\Omega_p

is calculated. In a following note in this journal, the investigation of the contact problem will be continued by detailed study of the singular integral equation system.
Distributional Controls in Processes with Hammerstein Type Integral Equations
Authors: Abuladze A. , Klötzler Rolf
Published: December 2016

The paper deals with problems of optimal control in which the control in general appears non-linear and in distributional sense, that means as limits of regular distributional sequences. For this a generalization of necessary conditions of optimality is provided (whibh is also sufficient in the linear case).
On the Perturbation of Critical Values of Maximum-Minimum Type
Authors: Benkert Frank
Published: December 2016

The stability of critical values of a functional under small perturbations is investigated. There are considered critical values of maximum-minimum type of functionals which are related to boundary value and cigenvalue problems for semilinear elliptic partial differential equations.
Pseudo differential operators in Hardy–Triebel spaces
Authors: Päivärinta Lassi
Published: December 2016

Pseudo differential operators of class

L^0_{\delta, \varrho}, \varrho = 1

and

0 \leq \delta < 1

are proved to be continuous in Triebel spaces

F^s_{p,q}

.
A Generalization of the Barnes $G$-Function
Authors: Schuster Reinhard
Published: December 2016

Generalizing the Barnes

G

-function we define an entire function of order

m

with the zeros

k

with multiplicity

k^m (k, m \in \mathbb N)

. We prove functional equations for it and study its asymptotic behaviour and Taylor series. This generalization is useful in order to describe the topological zeros of the Selberg zeta function with respect to the spectrum of the Laplace operator for differential

p

-forms on

n

-dimensional compact hyperbolic space forms.
Asymptotics of the Solution of a Boundary Integral Equation Under a Small Perturbation of a Corner
Authors: Maz'ya Vladimir G. , Mahnke Ralf
Published: December 2016

The boundary integral equation of the Dirichlet problem is considered in a plane domain with a smooth boundary which is a small perturbation of a contour with an angular point. The asymptotics of the solution are given with respect to a perturbation parameter

\epsilon

. The problem studied in this article serves as an example of the use of a general method which is also applicable to the three-dimensional case, to the Neumann problem and to problems of hydrostatics and elasticity.
The SILP-Relaxation Method in Optimal Control I: General Boundary Conditions
Authors: Rudolph Helmut
Published: December 2016

The paper deals with the relaxation method,a measure-theoretical approach for the treatment of classical control problems. After establishing a linear program over measure spaces as a substitute for a control problem, it is possible to use methods of semi-infinite linear programming (SILP), especially the semi-infinite simplex method (SISM), in order to estimate the solution of the linear program. In this way, approximations for the global optimal solution of the control problem can be obtained; a lower bound for the corresponding optimal value can also be found, by means of duality theory.
Some Results on the Invertibility of Wiener-Hopf-Hankel Operators
Authors: Lebre A.B. , Meister E. , Teixeira F.S.
Published: December 2016

A study is presented on the invertibility properties of scalar operators defined as the sum of a Wiener-Hopf and a Hankel operator on

L_2(\mathbb R^+)

with symbols in

L_{\infty}(\mathbb R)

. This study is based on the properties of a vector Wiener-Hopf operator naturally associated with each of the operators mentioned above. The results obtained are applied to problems in Diffraction Theory.
Bergmansche Integraloperatoren für instationäre Prozesse in der Ebene
Authors: Lanckau Eberhard
Published: December 2016

The complex integral operators of S. Bergman transform holomorphic functions of a complex variable into solutions of linear partial differential equations of elliptic type. In this way they make possible to construct explicitly these solutions and to study their properties by function-theoretic methods. We offer a generalization of Bergman’s operator method by which linear equations for time-dependent processes in the plane may be treated uniquely.
The first boundary value problem for classical equations of mathematical physics in domains with piecewise-smooth boundaries. I (in Russian)
Authors: Maz'ya Vladimir G. , Plamenevskii Boris A.
Published: December 2016

The first boundary value problem for the Stokes, Navier-Stokes, Lamé sytems and for the Laplace equation in a bounded domain

\Omega \subset \mathbb R^3

is studied. The boundary of

\Omega

contains singularities, such as conic points, edges or polyhedral angles. Theorems on solvability in spaces, supplied with weighted

L_s-

and

C^{\alpha}-

norms (

1 < s < \infty, 0 < \alpha < 1

) are proved. Coercive estimates of solutions in these spaces as well as pointwise estimates of the Green functions are obtained. The change of properties of generalized solutions under the change of right-hand sides is observed.
Quasilineare elliptische Differentialgleichungen zweiter Ordnung in mehrdimensionalen Gebieten mit Kegelspitzen
Authors: Miersemann Erich
Published: December 2016

We study regularity properties for solutions

u

of a class of quasilinear elliptic boundary value problems of second order in

n

-dimensional domains with conic vertices. We prove

u \in C^{1, \lambda} \cap H^2

near the vertex.
Oberflächeninstabilitäten magnetischer Flüssigkeiten
Authors: Beyer Klaus
Published: December 2016

We continue here the study of periodic equilibrium states of a magnetic fluid in an exterior magnetic field yet considered in [2]. In this paper we calculate holohedry-invariant equilibrium solutions on hexagonal lattices.
Uniform approximation by solutions of general boundary value problems for elliptic equations of arbitrary order I
Authors: Wildenhain Günther
Published: December 2016

Let

\Omega \subset \mathbb R^n

be a bounded, smooth domain,

\Gamma

a closed, smooth,

(n-1)

-dimensional surface in the interior of

\Omega

and

V

an open subset of the boundary

\partial \Omega

. In

\Omega

we consider a properly elliptic differential operator

L

of arbitrary order with smooth coefficients. Let

B_1, \dots, B_m

be a normal system of boundary operators on

\partial \Omega

, which fulfils the classical roots condition.

L_V(\Gamma)

denotes the space of the restrictions on

\Gamma

of the functions from

L_V(\Omega) = \{u: Lu = 0 \: \mathrm {in} \: \Omega, B_1 u|_{\partial \Omega} =\dots = B_m u|_{\partial \Omega} = 0 \: \mathrm {in} \: \partial \Omega \setminus V \}.

Among other things it is proved, that the space

L_V(\Gamma)

is dense in the space

W^{m-1} (\Gamma)

of the Whitney-Taylorfields of the order

m-1

, i.e. all derivatives up to the order

m-1

can be uniformly approximated on

\Gamma

.
Zur Existenz einer Lösung für ein bestimmtes parabolisches Randsteuerproblem
Authors: Sperber Wolfram
Published: December 2016

This paper investigates the existence of an optimal control for a control problem with a parabolic state equation. The state equation of the boundary control problem is a weakly nonlinear parabolic third initial boundary value problem. For this problem a generalized solution is defined by means of the integral equation method. The existence of a solution is proved by an approximation using solutions of classically solvable problems. To show the existence of an optimal control a generalization of the theorem of Weierstrass to lower semi-continuous functionals on reflexive Banach spaces is used.
Necessary optimality conditions for systems described by nonlinear elliptic equations. I (in Russian)
Authors: Raitums Uldis
Published: December 2016

This paper considers optimal control problems for systems governed by second order elliptic differential equations in divergence form with nonlinear terms and control appear in all terms. The representation of the main part of increment for a solution of the state equation is given in the case of needle-like variations.
Nighttime atmospheric chemistry of iodine
Authors: Saiz-Lopez Alfonso , Plane John M. C. , Cuevas Carlos A. , Mahajan Anoop S. , Lamarque Jean-François , Kinnison Douglas E.
Published: December 2016

Abstract. Little attention has so far been paid to the nighttime atmospheric chemistry of iodine species. Current atmospheric models predict a buildup of HOI and I2 during the night that leads to a spike of IO at sunrise, which is not observed by measurements. In this work, electronic structure calculations are used to survey possible reactions that HOI and I2 could undergo at night in the lower troposphere, and hence reduce their nighttime accumulation. The new reaction NO3+ HOI  →  IO + HNO3 is proposed, with a rate coefficient calculated from statistical rate theory over the temperature range 260–300 K and at a pressure of 1000 hPa to be k(T)  =  2.7  ×  10−12 (300 K/T)2.66 cm3 molecule−1 s−1. This reaction is included in two atmospheric models, along with the known reaction between I2 and NO3, to explore a new nocturnal iodine radical activation mechanism. The results show that this iodine scheme leads to a considerable reduction of nighttime HOI and I2, which results in the enhancement of more than 25 % of nighttime ocean emissions of HOI + I2 and the removal of the anomalous spike of IO at sunrise. We suggest that active nighttime iodine can also have a considerable, so far unrecognized, impact on the reduction of the NO3 radical levels in the marine boundary layer (MBL) and hence upon the nocturnal oxidizing capacity of the marine atmosphere. The effect of this is exemplified by the indirect effect on dimethyl sulfide (DMS) oxidation.
Numerical simulations of windblown dust over complex terrain: The Fiambalá Basin episode in June 2015
Authors: Mingari Leonardo A. , Collini Estela A. , Folch Arnau , Báez Walter , Bustos Emilce , Osores María Soledad , Reckziegel Florencia , Alexander Peter , Viramonte José G.
Published: December 2016

Abstract. On the 13 June 2015, the London Volcanic Ash Advisory Centre (VAAC) warned the Buenos Aires VAAC about a possible volcanic eruption from the Nevados Ojos del Salado volcano (6879 m), located in the Andes mountain range on the border between Chile and Argentina. A volcanic ash cloud was detected by the SEVIRI instrument on board the Meteosat Second Generation (MSG) satellites from 14:00 UTC on 13 June. Further studies concluded that the phenomenon was caused by remobilization of ancient pyroclastic deposits (circa 4.5 Ka Cerro Blanco eruption) from the Bolsón de Fiambalá (Fiambalá Basin) in northwestern Argentina. In this paper, we provide the first comprehensive description of the dust episode through observations and numerical simulations. We have investigated the spatio-temporal distribution of aerosols and the emission process over complex terrain to gain insight into the key role played by the orography and the condition that triggered the long-range transport episode. Numerical simulations of windblown dust were performed using the WRF-ARW/FALL3D modeling system with meteorological fields downscaled to a spatial resolution of 2 km in order to resolve the complex orography of the area. Results indicated that favourable conditions to generate dust uplifting occurred in northern Fiambalá Basin, where orographic effects caused strong surface winds. According to short-range numerical simulations, dust particles were confined to near-ground layers around the emission areas. On the other hand, dust aerosols were injected up to 5–6 km high in central and southern regions of the Fiambalá Basin, where intense ascending airflows are driven by horizontal convergence. Long-range transport numerical simulations were also performed to model dust cloud spreading over northern Argentina. Results of simulated vertical particle column mass were compared with the MSG-SEVIRI retrieval product. We tested two numerical schemes: with the default configuration of the FALL3D model, we found difficulties to simulate transport through orographic barriers, whereas an alternative configuration, using a numerical scheme to more accurately compute the horizontal advection in abrupt terrains, substantially improved the model performance.
Characterisation of interferences to in-situ observations of δ13CH4 and C2H6 when using a Cavity Ring Down Spectrometer at industrial sites
Authors: Assan Sabina , Baudic Alexia , Guemri Ali , Ciais Philippe , Gros Valerie , Vogel Felix R.
Published: December 2016

Abstract. The increase of atmospheric methane (CH4) is the second largest contributor to the increased radiative forcing since the industrial revolution. Natural gas extraction and distribution is associated with CH4 leaks of uncertain magnitude that has spurred interest for developing new methods to measure them. Using a CRDS instrument we evaluate two methane identification methods commonly used to better constrain emission estimates from natural gas leaks, namely stable isotope analysis and the ethane: methane ratio (C2H6 : CH4). Recently it has come to light that CRDS measurements of δ13CH4 and C2H6 in the near infrared spectral domain are subject to cross sensitivities due to absorption from multiple gases. These sensitivities translate into biases in the retrieval of δ13CH4 and C2H6 concentrations in air samples, and should thus be accounted for during data processing. Here we present extensive laboratory tests using two CRDS instruments to characterize their cross sensitivities and propose corrections to calculate unbiased δ13CH4 and C2H6. Methane isotopic measurements were found to be subject to interference from elevated C2H6 concentrations (a secondary component in many natural gas types) resulting in heavier δ13CH4 by +23.5 ‰ per ppm C2H6 / ppm CH4. Measured C2H6 is subject to absorption interference from a number of other trace gases, the predominant being H2O (with an average linear sensitivity of 0.9 ppm C2H6 per % H2O in ambient conditions, meaning that the presence of H2O causes the inference of too high C2H6 mixing ratios if no correction is applied). Yet, this sensitivity was found to be discontinuous with a strong hysteresis effect. Throughout the range of C2H6 concentrations measured in this study (0–5 ppm C2H6), both CRDS instruments consistently measure concentrations double that reported by a GC, thus we have calculated a calibration factor of 0.5. To demonstrate the significance of the corrections we test the source identification methods on air measured at a natural gas compressor station. The presence of C2H6 in gas emissions at an average level of 0.3 ppm was found to shift the isotopic signature by 2.5 ‰. We find that after correction and calibration the average C2H6 : CH4 ratio shifts by +0.06. These results indicate that when using such a CRDS instrument in conditions of elevated C2H6 for CH4 source determination it is imperative to account for the biases discussed within this study.
The importance of snowmelt spatiotemporal variability for isotope-based hydrograph separation in a high-elevation catchment
Authors: Schmieder Jan , Hanzer Florian , Marke Thomas , Garvelmann Jakob , Warscher Michael , Kunstmann Harald , Strasser Ulrich
Published: December 2016

Abstract. Seasonal snow cover is an important temporary water storage in high-elevation regions. Especially in remote areas, the available data are often insufficient to accurately quantify snowmelt contributions to streamflow. The limited knowledge about the spatiotemporal variability of the snowmelt isotopic composition, as well as pronounced spatial variation in snowmelt rates, leads to high uncertainties in applying the isotope-based hydrograph separation method. The stable isotopic signatures of snowmelt water samples collected during two spring 2014 snowmelt events at a north- and a south-facing slope were volume weighted with snowmelt rates derived from a distributed physics-based snow model in order to transfer the measured plot-scale isotopic composition of snowmelt to the catchment scale. The observed δ18O values and modeled snowmelt rates showed distinct inter- and intra-event variations, as well as marked differences between north- and south-facing slopes. Accounting for these differences, two-component isotopic hydrograph separation revealed snowmelt contributions to streamflow of 35 ± 3 and 75 ± 14 % for the early and peak melt season, respectively. These values differed from those determined by formerly used weighting methods (e.g., using observed plot-scale melt rates) or considering either the north- or south-facing slope by up to 5 and 15 %, respectively.
Assessing population exposure for landslide risk analysis using dasymetric cartography
Authors: Garcia Ricardo A. C. , Oliveira Sérgio C. , Zêzere José L.
Published: December 2016

Abstract. Assessing the number and locations of exposed people is a crucial step in landslide risk management and emergency planning. The available population statistical data frequently have insufficient detail for an accurate assessment of potentially exposed people to hazardous events, mainly when they occur at the local scale, such as with landslides. The present study aims to apply dasymetric cartography to improving population spatial resolution and to assess the potentially exposed population. An additional objective is to compare the results with those obtained with a more common approach that uses, as spatial units, basic census units, which are the best spatial data disaggregation and detailed information available for regional studies in Portugal. Considering the Portuguese census data and a layer of residential building footprint, which was used as ancillary information, the number of exposed inhabitants differs significantly according to the approach used. When the census unit approach is used, considering the three highest landslide susceptible classes, the number of exposed inhabitants is in general overestimated. Despite the associated uncertainties of a general cost–benefit analysis, the presented methodology seems to be a reliable approach for gaining a first approximation of a more detailed estimation of exposed people. The approach based on dasymetric cartography allows the spatial resolution of population over large areas to be increased and enables the use of detailed landslide susceptibility maps, which are valuable for improving the exposed population assessment.
Influencing factors and development patterns of cracking–sliding
failure of loess in China
Authors: Mao Jiarui , Xiang Xiqiong , Li Yanrong
Published: December 2016

Abstract. Loess is a porous, weakly cemented, and unsaturated Quaternary sediment deposited in arid and semi-arid regions by the wind. It is widely and thickly distributed in China, making the Loess Plateau the largest bulk accumulation of loess on the Earth. However, the fragile geoenvironment in the loess areas of China causes frequent and various geohazards, among which, the Cracking-sliding (Beng-hua) is a typical failure mode because it causes the largest number of casualties each year. This study investigates the development pattern and main influencing factors of cracking–sliding failure to help in effectively preventing its occurrence and reducing losses. The following conclusions are derived: (1) cracking–sliding failures are prone to occur in rectilinear slopes, convex slopes, slopes with gradients greater than 60°, slopes with heights of 5 m to 40 m, and sunward slopes with aspects of 180° to 270°; (2) cracking–sliding failures occur mostly from 9 p.m. to 4 a.m. the next day, and concentrates in the rainy season (July to September) and freeze-thaw season (March to May); and (3) the more intense the human activities in the region, the greater the possibility of cracking–sliding failures.
A 240 year History of Avalanche Risk in the Vosges Mountains from Nonconventional Sources
Authors: Giacona Florie , Eckert Nicolas , Martin Brice
Published: December 2016

Abstract. Despite their strong societal impact, systematic documentation of mountain risks remains poor. Thus, snow avalanche chronologies exceeding several decades are exceptional, especially in medium-high mountain ranges where activity can still be significant. This article implements a combination of historical and geographical methods leading to the reconstruction, at the scale of the entire Vosges Massif (north-east of France), of more than seven hundred avalanches that have occurred since the late eighteenth century on 128 paths. The clearly episodic nature of the derived geo-chronology can be explained by three interrelated factors that have changed together over time: the body and reliability of sources, social practices conditioning the vulnerability, and the natural hazard itself. Finally, the geo-chronology primarily reflects the evolution of the meaning of the hazard in the social space. Specifically, the event which could be retrieved from the historical sources is an aspect of the interaction between society and its environment. These results confirm the role of the historian in contextualizing and evaluating such data, transforming them into information relevant for risk changes understanding and mitigation. They also highlight the importance of constructing an original database from a diverse suite of historical data, and testing its fidelity using field investigations at an appropriate spatial scale. This general approach is of great utility for investigating other risk phenomena in the frequent situation where conventional sources are sparse and problematic to assemble.
Evaluation of snow cover and snow depth on the Qinghai-Tibetan
Plateau derived from passive microwave remote sensing
Authors: Dai Liyun , Che Tao , Ding Yongjian , Hao Xiaohua
Published: December 2016

Abstract. Snow cover on the Qinghai-Tibetan plateau (QTP) plays a significant role in the global climate system and is an important water resource for rivers in the high elevation region of Asia. At present, passive microwave (PM) remote sensing data are the only efficient way to monitor temporal and spatial variations in snow depth at large scale. However, existing snow depth products show the largest uncertainties across the QTP. In this study, MODIS fractional snow cover product, in situ observations, and airborne observation data are synthesized to evaluate the accuracy of snow cover and snow depth derived from PM remote sensing data and to analyze the possible causes of uncertainties. The results show that the accuracy of snow cover extents varies spatially and depends on the fraction of snow cover. Based on the assumption that grids with MODIS snow cover fraction > 10 % are regarded as snow cover, the overall accuracy in snow cover is 66.7 %, overestimation error is 56.1 %, underestimation error is 21.1 %, commission error is 27.6 % and omission error is 47.4 %. The commission and overestimation errors of snow cover primarily occur in the northwest and southeast areas with low ground temperature. Omission error primarily occurs in cold desert areas with shallow snow, and underestimation error mainly occurs in glacier and lake areas. Comparison between snow depths measured in field experiments, measured at meteorological stations and estimated across the QTP shows that agreement between observation and retrieval improves with an increasing number of observation points in a PM grid. The misclassification and errors between observed and retrieved snow depth are associated with the relatively coarse resolution of PM remote sensing, ground temperature, snow characteristics and topography. To accurately understand the variation in snow depth across the QTP, new algorithms should be developed to retrieve snow depth with higher spatial resolution and should consider the variation in brightness temperatures at different frequencies emitted from ground with changing ground features.
Turbulence characterization from a forward-looking nacelle lidar
Authors: Peña Alfredo , Mann Jakob , Dimitrov Nikolay
Published: December 2016

Abstract. We present two methods to characterize turbulence in the turbine inflow using radial velocity measurements from nacelle-mounted lidars. The first uses a model of the three-dimensional spectral velocity tensor combined with a model of the spatial radial velocity averaging of the lidars and the second uses the ensemble-averaged Doppler radial velocity spectrum. With the former, filtered turbulence estimates can be predicted, whereas the latter model-free method allows us to estimate unfiltered turbulence measures. Two types of forward-looking nacelle lidars are investigated: a pulsed system that uses a 5-beam configuration and a continuous-wave system that scans conically. For both types of lidars, we show how the radial velocity spectra of the lidar beams are influenced by turbulence characteristics and how to extract the velocity-tensor parameters that are useful to predict the loads on a turbine. We also show how the velocity-component variances and co-variances can be estimated from the radial-velocity unfiltered variances of the lidar beams. We demonstrate the methods using measurements from an experiment conducted at the Nørrekær Enge wind farm in northern Denmark, where both types of lidars were installed on the nacelle of a wind turbine. Comparison of the lidar-based along-wind unfiltered variances with those from a cup anemometer installed on a meteorological mast close to the turbine shows a bias of just 2 %. The ratios of the unfiltered and filtered radial velocity variances of the lidar beams to the cup-anemometer variances are well predicted by the spectral model. However, other lidar-derived estimates of velocity-component variances and co-variances do not agree with those from a sonic anemometer on the mast, which we mostly attribute to the small cone angle of the lidar. The velocity-tensor parameters derived from sonic-anemometer velocity spectra and those derived from lidar radial velocity spectra agree well under both near-neutral atmospheric stability and high wind-speed conditions with differences increasing with decreasing wind-speed and increasing stability. We also partly attribute these differences to the lidar beam configuration.
El biógrafo de García Lorca, el amigo de Negrín
Authors: Expósito Extremera Francisco
Published: December 2016

Fernando Vázquez Ocaña (Baena, 1898-México DF, 1966) abandonaba España en febrero de 1939. Comenzaba así el olvido del periodista. Su figura permaneció en el anonimato durante cincuenta años, a pesar de que fue diputado a Cortes en 1933, se convirtió en portavoz del Gobierno de Negrín o director de periódicos como La Vanguardia o El Socialista (en su edición de México). Detrás de Vázquez Ocaña había una brillante trayectoria periodística y profesional que estuvo marcada por desagradables acontecimientos como la muerte de su esposa, con 37 años, el reparto de sus ocho hijos entre familias belgas, su exilio en 1939 y la imposibilidad de volver a España. En 1957 publicó en México DF una de las primeras biografías sobre Federico García Lorca en el exilio.
Recordando a Maruja Boga. La voz de la emigración gallega en la radiofonía Argentina
Authors: Piñeiro-Otero Teresa , Encina García-Cofrades María de la
Published: December 2016

El fenómeno de la emigración gallega a América conllevó la aparición de una Galicia en ultramar. El peso y dinamismo de esta emigración en las sociedades de acogida, especialmente en la Argentina, favoreció la aparición de numerosas publicaciones y programas radiales que trataron los intereses de la colectividad y reforzaron su vínculo con Galicia. Entre ellas destaca Recordando a Galicia (Buenos Aires, 1945-1984) una audición cultural que supuso un alegato del galeguismo con el que su directora, Maruja Boga, estaba comprometida. A pesar de que su voz pervive en la memoria colectiva de la emigración, Boga no ha recibido la atención de otros comunicadores de la Galicia ultramar.
Introducción. Matrimonio en los siglos XVI-XVIII: derecho canónico, conflictos y realidad social
Authors: De Zaballa Beascoechea Ana
Published: December 2016

Introducción. Matrimonio en los siglos XVI-XVIII: derecho canónico, conflictos y realidad social
Signos y palabras: la celebración del matrimonio tridentino en Lima y Charcas (s. XVI-XVIII)
Authors: Latasa Pilar
Published: December 2016

La publicidad en la celebración del matrimonio fue uno de los aspectos esenciales abordados por los padres reunidos en el Concilio de Trento. A partir de ese momento se introdujeron antes, durante y después de la ceremonia nupcial una serie de condiciones que garantizaban esta publicidad, algunas de las cuales fueron, además, requerimientos para la validez del vínculo. Esta normativa tridentina se implementó pronto también en la América hispana. El trabajo aborda la aplicación del nuevo ritual matrimonial en los territorios de las archidiócesis de Lima y Charcas antes de la Pragmática Sanción de 1776. Con ese fin, se analizan tanto las disposiciones de concilios y sínodos locales, como los instrumentos de pastoral que más circularon en el ámbito andino.