bluuebunny/crossref_metadata_2025 huggingface dataset:
Gruppi fattorizzati da sottogruppi abeliani
Authors: Jabara Enrico
Published: December 2012

Let
G
= _A_1_A_2_A_3 be a group that is a product of three mutually permutable abelian subgroups _A_1, _A_2 and _A_3. In this paper we prove that if _A_1_A_2 is nilpotent then
G
is soluble and that if _A_1_A_2, _A_1_A_3 and _A_2_A_3 are nilpotent then
G
is also nilpotent.
Atiyah Classes and Closed Forms on Moduli Spaces of Sheaves
Authors: Bottacin Francesco
Published: December 2012

Let

X

be a smooth

n

-dimensional projective variety, and let

Y

be a moduli space of stable sheaves on

X

. By using the local Atiyah class of a universal family of sheaves on

Y

, which is well defined even when such a universal family does not exist, we are able to construct natural maps

f: H^i(X, Ω_X^j) → H^{k+i-n} (Y, Ω_Y^{k+j-n}),

for any

i, j = 1,…,n

and any

k ≥ \max\{n-i, n-j\}

. In particular, for

k = n-i

, the map

f

associates a closed differential form of degree

j-i

on the moduli space

Y

to any element of

H^i(X,Ω_X^j)

. This method provides a natural way to construct closed differential forms on moduli spaces of sheaves. We remark that no smoothness hypothesis is made on the moduli space

Y

. As an application, we describe the construction of closed differential forms on the Hilbert schemes of points of

X

.
A Short Proof of the Minimality of Simons Cone
Authors: De Philippis Guido , Paolini Emanuele
Published: December 2012

In 1969 Bombieri, De Giorgi and Giusti proved that Simons cone is a minimal surface, thus providing the first example of a minimal surface with a singularity. We suggest a simplified proof of the same result. Our proof is based on the use of sub-calibrations, which are unit vector fields extending the normal vector to the surface, and having non-positive divergence. With respect to calibrations (which are divergence free) sub-calibrations are more easy to find and anyway are enough to prove the minimality of the surface.
A Threefold with $p_g=0$ and $P_2=2$
Authors: Stagnaro Ezio
Published: December 2012

We construct a nonsingular threefold

X

with

q_1 = q_2 = p_g = 0

and

P_2 = 2

whose

m

-canonical transformation

φ_{|mK_X|}

has the following properties

i)

φ_{|mK_X|}

has the generic fiber of dimension

≥ 1

, for

2 ≤ m ≤ 5

;

ii) it is generically a tranformation 2 : 1, for

6 ≤ m ≤ 8

and

m = 10

;

iii) it is birational for

m = 9

and

m ≥ 11

.

So, we have a gap for

m =10

in the birationality of

φ_{|mK_X|}

.

.
Idempotent Subreducts of Semimodules over Commutative Semirings
Authors: Stankovský David
Published: December 2012

A short proof of the characterization of idempotent subreducts of semimodules over commutative semirings is presented. It says that an idempotent algebra embeds into a semimodule over a commutative semiring, if and only if it belongs to the variety of Szendrei modes.
The Thermistor Obstacle Problem with Periodic Data
Authors: Badii Maurizio
Published: December 2012

The object of this paper is the study of an obstacle thermistor problem with a nonlocal term. Using the classical Lax–Milgram theorem, a result of Lions and a fixed point argument we prove existence of weak periodic solutions. Finally, by means of some a-priori estimates in Campanato's spaces, we obtain the regularity of these solutions.
On the Regularity for Solutions of the Micropolar Fluid Equations
Authors: Ortega-Torres Elva , Rojas-Medar Marko
Published: December 2012

We give sufficient conditions on the kinematics pressure in order to obtain regularity and uniqueness of the weak solutions to the micropolar fluid equations.
A Note on Posner's Theorem with Generalized Derivations on Lie Ideals
Authors: De Filippis V. , Tammam El-Sayid M.S.
Published: December 2012

Let

R

be a prime ring of characteristic different from

2

,

Z(R)

its center,

U

its Utumi quotient ring,

C

its extended centroid,

G

a non-zero generalized derivation of

R

,

L

a non-central Lie ideal of

R

. We prove that if

[[G(u),u],G(u)] \in Z(R)

for all

u\in L

then one of the following holds:
GIT Quotients of Products of Projective Planes
Authors: Incensi Francesca
Published: December 2012

We study the quotients for the diagonal action of

\mathit{SL}_3(\mathbb C)

on the

n

-fold product of

\mathbb P^2(\mathbb C)

: we are interested in describing how the quotient changes when we vary the polarization (i.e. the choice of an ample linearized line bundle). We illustrate the different techniques for the construction of a quotient, in particular the numerical criterion for semi-stability and the “elementary transformations” which are resolutions of precisely described singularities (case

n = 6

).
On Certain Characterizations of Barely Transitive Groups
Authors: Arikan Ahmet , Trabelsi Nadir
Published: December 2012

In the present work we study perfect barely transitive groups in which a point stabilizer has non-trivial Hirsch–Plotkin radical and give characterizations of these groups. We also prove that a perfect barely transitive group has two non-trivial proper subgroups which intersect trivially.
GAGA for DQ-Algebroid
Authors: Chen Hou-Yi
Published: December 2012

Let

X

be a smooth complex projective variety with associated compact manifold

X_{\mathrm{an}}

. If

\mathscr A_X

is a DQ-algbroid on

X

, then there is an induced DQ-algebroid

\mathscr A_{X_{\mathrm{an}}}

on

X_{\mathrm{an}}

. We show that the natural functor from the derived category of bounded complexes of

\mathscr A_X

-modules with coherent cohomologies to the derived category of bounded complexes of

\mathscr A_{X_{\mathrm{an}}}

-modules with coherent cohomologies is an equivalence.
On Cover-Avoiding Subgroups of Sylow Subgroups of Finite Groups
Authors: Li Yangming
Published: December 2012

A subgroup

H

of a finite group

G

is called to have the cover-avoidance property in

G

,

H

is a CAP subgroup of

G

in short, if

H

either covers or avoids every chief factor of

G

. In the present work, we fix a subgroup

D

in every Sylow subgroup

P

of

F^* (G)

satisfying

1 <|D| < |P_|

and study the structure of

G

under the assumption that every subgroup

H

with

|H | = |D|

has the cover-avoidance property in

G

. We state our results in the broader context of formation theory.
Contracting the Socle in Rings of Continuous Functions
Authors: Dube Themba
Published: December 2012

Not every ring homomorphism contracts the socle of its codomain to an ideal contained in the socle of its domain. Rarer still does a homomorphism contract the socle to the socle. We find conditions on a frame homomorphism that ensure that the induced ring homomorphism contracts the socle of the codomain to an ideal contained in the socle of the domain. The surjective among these frame homomorphisms induce ring homomorphisms that contract the socle to the socle. These homomorphisms characterize

P

-frames as those

L

for which every frame homomorphism with

L

as domain is of this kind.
Holomorphic Extension from Weakly Pseudoconcave CR Manifolds
Authors: Altomani Andrea , Hill C. Denson , Nacinovich Mauro , Porten Egmont
Published: December 2012

Let

\mathrm{M}

be a smooth locally embeddable CR manifold, having some CR dimension

m

and some CR codimension

d

. We find an improved local geometric condition on

\mathrm{M}

which guarantees, at a point

p

on

\mathrm{M}

, that germs of CR distributions are smooth functions, and have extensions to germs of holomorphic functions on a full ambient neighborhood of

p

. Our condition is a form of weak pseudoconcavity, closely related to essential pseudoconcavity as introduced in [HN1]. Applications are made to CR meromorphic functions and mappings. Explicit examples are given which satisfy our new condition, but which are not pseudoconcave in the strong sense. These results demonstrate that for codimension

d > 1

, there are additional phenomena which are invisible when

d = 1

.
Structure and Detection Theorems for $k[C_2\times C_4]$-Modules
Authors: Öztürk Kaptanoglu Semra
Published: December 2012

Let

k[G]

be the group algebra, where

G

is a finite abelian

p

-group and

k

is a field of characteristic

p

. A complete classification of finitely generated

k[G]

-modules is available only when

G

is cyclic,

C_{p^n}

, or

C_2×C_2

. Tackling the first interesting case, namely modules over

k[C_2×C_4]

, some structure theorems revealing the differences between elementary and non-elementary abelian group cases are obtained. The shifted cyclic subgroups of

k[C_2×C_4]

are characterized. Using the direct sum decompositions of the restrictions of a

k[C_2×C_2]

-module

M

to shifted cyclic subgroups we define the set of multiplicities of

M

. It is an invariant richer than the rank variety. Certain types of

k[C_2×C_4]

-modules having the same rank variety as

k[C_2×C_2]

-modules can be detected by the set of multiplicities, where

C_2×C_2

is the unique maximal elementary abelian subgroup of

C_2×C_4

.
Some Remarks on Uniqueness and Regularity of Cheeger Sets
Authors: Caselles Vicent , Chambolle Antonin , Novaga Matteo
Published: December 2012

We show that generically the subsets of

\mathbb R^N

with finite volume have a unique Cheeger set, in the sense that there always exists a nearby set which has a unique Cheeger set. We also prove that Cheeger sets are

C^{1,1}

, when the ambient set is

C^{1,1}

.
Levi Curvature with Radial Symmetry: a Sphere Theorem for Bounded Reinhardt Domains of $\mathbb C^2$
Authors: Tralli Giulio
Published: December 2012

We study bounded Reinhardt domains of

\mathbb C^2

, whose Levi curvature depends on the distance from the origin. We prove that a radial decrease of the Levi curvature forces the domain to be a ball.
Ilmanen's Lemma on Insertion of $\mathbb C^{1,1} Functions
Authors: Fathi Alberto , Zavidovique Maxime
Published: December 2012

We give a proof of Ilmanen's lemma, which asserts that between a locally semi-convex and a locally semi-concave function it is possible to find a

\mathbb C^{1,1}

function.
Right Utumi P.P.-Rings
Authors: Albrecht Ulrich
Published: December 2012

The class of right Utumi p.p.-rings plays a central role when developing a notion of torsion-freeness over non-commutative rings. This paper shows that it also arises naturally when considering divisible modules. Various notions of divisibility were introduced for modules over integral domains. We determine their relation in the non-commutative case and show that there are significant differences between this and the commutative setting. Finally, we determine large classes of semi-prime Goldie rings for which two or more of these notions coincide.
Periodic-by-Nilpotent Linear Groups
Authors: Wehrfritz B.A.F.
Published: December 2012

Let

G

be a linear group of (finite) degree

n

and characteristic

p ≥ 0

. Suppose that for every infinite subset

X

of

G

there exist distinct elements

x

and

y

of

X

with

\langle x, x^y\rangle

periodic-by-nilpotent. Then

G

has a periodic normal subgroup

T

such that if

p> 0

then

G/T

is torsion-free abelian and if

p = 0

then

G/T

is torsion-free nilpotent of class at most

\mathrm{max}{1, n-1}

and is isomorphic to a linear group of degree

n

and characteristic zero. We also discuss the structure of periodic-by-nilpotent linear groups.
Screen Transversal Lightlike Submanifolds of Indefinite Cosymplectic Manifolds
Authors: Gupta Ram Shankar , Sharfuddin Ahmad
Published: December 2012

In this paper, we introduce screen transversal lightlike submanifolds of indefinite Cosymplectic manifolds. Then, we study the geometry of this new class and its subspaces with example.
Subcritical Approximation of the Sobolev Quotient and a Related Concentration Result
Authors: Palatucci Giampiero
Published: December 2012

Let

\Omega

be a general, possibly non-smooth, bounded domain of

\mathbb{R}^N

,

N\geq 3

. Let

\displaystyle 2^{*}\!\!=\!{2N}\,\!/{(N-2)}

be the critical Sobolev exponent. We study the following variational problem

S^{*}_{\varepsilon}=\sup\left \{ \int_{\Omega}|u|^{2^{*}\!-\varepsilon}dx: \int_{\Omega}|\nabla u|^{2}dx\leq 1, u=0 \ \text{on} \ \partial\Omega \right \},

investigating its asymptotic behavior as

\varepsilon

goes to zero, by means of

\Gamma^+

-convergence techniques. We also show that sequences of maximizers

u_\varepsilon

concentrate energy at one point

x_0\in \overline{\Omega}

.
Tropical Open Hurwitz Numbers
Authors: Bertrand Benoît , Brugallé Erwan , Mikhalkin Grigory
Published: December 2012

We give a tropical interpretation of Hurwitz numbers extending the one discovered in [CJM]. In addition we treat a generalization of Hurwitz numbers for surfaces with boundary which we call open Hurwitz numbers.
Conic Sheaves on Subanalytic Sites and Laplace Transform
Authors: Prelli Luca
Published: December 2012

Let

E

be a

n

dimensional complex vector space and let

E^*

be its dual. We construct the conic sheaves

\mathcal O^t_{E_{{\mathbb{R}^{{\scriptscriptstyle{+}}}}}}

and

\mathcal O^{\mathrm{w}}_{E_{{\mathbb{R}^{{\scriptscriptstyle{+}}}}}}

of tempered and Whitney holomorphic functions respectively and we give a sheaf theoretical interpretation of the Laplace isomorphisms of [10] which give the isomorphisms in the derived category

\mathcal O^{t\land}_{E_{{\mathbb{R}^{{\scriptscriptstyle{+}}}}}}[n] \simeq\mathcal O^t_{E^*_{{\mathbb{R}^{{\scriptscriptstyle{+}}}}}}

and

\mathcal O^{\mathrm{w}\land}_{E_{{\mathbb{R}^{{\scriptscriptstyle{+}}}}}}[n] \simeq\mathcal O^{\mathrm{w}}_{E^*_{{\mathbb{R}^{{\scriptscriptstyle{+}}}}}}

.
An Integral Formula Related to Inner Isoptics
Authors: Martini Horst , Mozgawa Witold
Published: December 2012

An isoptic

C_\alpha

of a strictly convex

C^2

-curve in the plane is the locus of all points from which

C

is seen under the same fixed angle. The two supporting lines of

C

through such a point determine a secant of

C

, and the envelope of all these secants is the inner isoptic of

C

and

C_\alpha

. We describe an integral formula for inner isoptics in terms of quantities that naturally occur in this geometric configuration.
Commutativity of $\ast$-Prime Rings with Generalized Derivations
Authors: Ashraf Mohammad , Khan Almas
Published: December 2012

Let

R

be a 2-torsion free

\ast

-prime ring and

F

be a generalized derivation of

R

with associated derivation

d

. If

U

is a

\ast

-Lie ideal of

R

then in the present paper, we shall show that

U\subseteq Z(R)

if

R

admits a generalized derivation

F

(with associated derivation

d

) satisfying any one of the properties:
(i)

F[u,v]=[F(u),v]

,
(ii)

F(u\circ v)=F(u)\circ v

,
(iii)

F[u,v]=[F(u),v]+[d(v),u]

,
(iv)

F(u\circ v)=F(u)\circ v+d(v)\circ u

,
(v)

F(uv)±uv=0

and
(vi)

d(u)F(v)±uv=0

for all

u,v \in U

.
Some Results on the Partition of Groups
Authors: Farrokhi D.G. M.
Published: December 2012

We investigate some properties of partitions of groups. Some information on the structure of nilpotent groups as well the embedding of groups with nontrivial partitions into a larger one are discussed. Moreover, we consider the structure of groups admitting a nontrivial partition with 1, 2 or 3 subgroups (considering the whole group) with nontrivial partition and the relation between the number of subgroups with nontrivial partition and the number of primes dividing the order of the group. Finally we analyze the relation between the number of components of a nontrivial partition of a group and its order.
A Note on Minimal Galois Embeddings of Abelian Surfaces
Authors: Yoshihara Hisao
Published: December 2012

We show that the least number

N

such that an abelian surface has a Galois embedding in

\mathbb{P}^N

is seven and then we give examples of such surfaces.
Huppert's Conjecture for $Fi_{23}$
Authors: Alavi Seyed Hassan , Daneshkhah Ashraf , Tong-Viet H.P. , Wakefield Thomas P.
Published: December 2012

Let

G

denote a finite group and

\text{cd}(G)

the set of irreducible character degrees of

G

. Bertram Huppert conjectured that if

H

is a finite nonabelian simple group such that

\text{cd}(G)=\text{cd}(H)

, then

G\cong H \times A

, where

A

is an abelian group. Huppert verified the conjecture for many of the sporadic simple groups. We illustrate the arguments by presenting the verification of Huppert's Conjecture for

Fi_{23}

.
Generalized Dirac Operators on Lorentzian Manifolds and Propagation of Singularities
Authors: Antonini Paolo
Published: December 2012

We survey the correct definition of a generalized Dirac operator on a Space-Time and the classicla result about propagation of singularities. This says that light travels along light-like geodesics. Finally we show this is also true for generalized Dirac operators.
Quadratic Integral Solutions to Double Pell Equations
Authors: Veneziano Francesco
Published: December 2012

We study the quadratic integral points – that is, (

S

-)integral points defined over any extension of degree two of the base field – on a curve defined in

\mathbb{P}_3

by a system of two Pell equations. Such points belong to three families explicitly described, or belong to a finite set whose cardinality may be explicitly bounded in terms of the base field, the equations defining the curve and the set

S

. We exploit the peculiar geometry of the curve to adapt the proof of a theorem of Vojta, which in this case does not apply.
Finite Groups with Weakly $s$-Semipermutable Subgroups
Authors: Li Changwen
Published: December 2012

Suppose

G

is a finite group and

H

is a subgroup of

G

.

H

is said to be

s

-semipermutable in

G

if

HG_{p} = G_{p}H

for any Sylow

p

-subgroup

G_{p}

of

G

with

(p, |H|)=1

;

H

is called weakly

s

-semipermutable in

G

if there is a subgroup

T

of

G

such that

G=HT

and

H\cap T

is

s

-semipermutable in

G

. We investigate the influence of weakly

s

-semipermutable subgroups on the structure of finite groups. Some recent results are generalized and unified.
Realization Theorems for Valuated $p^n$-Socles
Authors: Keef Patrick W.
Published: December 2012

If

n

is a positive integer and

p

is a prime, then a valuated

p^n

-socle is said to be

n

-summable if it is isometric to a valuated direct sum of countable valuated groups. The functions from

\omega_1

to the cardinals that can appear as the Ulm function of an

n

-summable valuated

p^n

-socle are characterized, as are the

n

-summable valuated

p^n

-socles that can appear as the

p^n

-socle of some primary abelian group. The second statement generalizes a classical result of Honda from [9]. Assuming a particular consequence of the generalized continuum hypothesis, a complete description is given of the

n

-summable groups that are uniquely determined by their Ulm functions.
On the Components of the Push-out Space with Certain Indices
Authors: Kaya Yusuf
Published: December 2012

Given an immersion of a connected,

m

-dimensional manifold

M

without boundary into the Euclidean

(m+k)

-dimensional space, the idea of the
push-out space
of the immersion under the assumption that immersion has flat normal bundle is introduced in [3]. It is known that the push-out space has finitely many path-connected components and each path-connected component can be assigned an integer called the index of the component. In this study, when

M

is compact, we give some new results on the push-out space. Especially it is proved that if the push-out space has a component with index

1

, then the Euler number of

M

is

0

and if the immersion has a co-dimension

2

, then the number of path-connected components of the push-out space with index

(m-1)

is at most 2.
A Convergence Theorem for Immersions with $L^2$-Bounded Second Fundamental Form
Authors: Ndiaye Cheikh Birahim , Schätzle Reiner
Published: December 2012

In this short note, we prove a convergence theorem for sequences of immersions from some closed surface

\Sigma

into some standard Euclidean space

\mathbb{R}^n

with

L^2

-bounded second fundamental form, which is suitable for the variational analysis of the famous Willmore functional, where

n\geq 3

. More precisely, under some assumptions which are automatically verified (up to subsequence and an appropriate Möbius transformation of

\mathbb{R}^n

) by sequences of immersions from some closed surface

\Sigma

into some standard Euclidean space

\mathbb{R}^n

arising from an appropriate stereographic projection of

\mathbb{S}^n

into

\mathbb{R}^n

of immersions from

\Sigma

into

\mathbb{S}^n

and minimizing the

L^2

-norm of the second fundamental form with

n\geq 3

, we show that the varifolds limit of the image of the measures induced by the sequence of immersions is also an immersion with some minimizing properties.
On the Fixed-Point Set and Commutator Subgroup of an Authomorphism of a Group of Finite Rank
Authors: Wehrfritz B.A.F.
Published: December 2012

Let

\phi

be an automorphism of a group

G

. For

G

polycyclic, Endimioni and Moravec in [1] discuss the relationship between the fixed-point set

C_G(\phi)

and the commutator subgroup

[G,\phi]

of

\phi

in

G

. Here we extend these results to soluble groups satisfying various rank restrictions.
The Arithmetic Theory of Local Constants for Abelian Varieties
Authors: Seveso Marco Adamo
Published: December 2012

We present a generalization of the theory of local constant developed by B. Mazur and K. Rubin in order to cover the case of abelian varieties, with emphasis to abelian varieties with real multiplication. Let

l

be an odd rational prime and let

L/K

be an abelian

l

-power extension. Assume that we are given a quadratic extension

K/k

such that

L/k

is a dihedral extension and the abelian variety

A/k

is defined over

k

and polarizable. This theory can be used to relate the rank of the

l

-Selmer group of

A

over

K

to the rank of the

l

-Selmer group of

A

over

L

.
Brownian Motion, Reflection Groups and Tanaka Formula
Authors: Demni Nizar , Lépingle Dominique
Published: December 2012

In the setting of finite reflection groups, we prove that the projection of a Brownian motion onto a closed Weyl chamber is another Brownian motion normally reflected on the walls of the chamber. Our proof is probabilistic and the decomposition we obtain may be seen as a multidimensional extension of Tanaka's formula for linear Brownian motion. The paper is closed with a description of the boundary process through the local times of the distances from the initial process to the facets.
Generalized Cotorsion Locally Compact Abelian Groups
Authors: Kryuchkov N.I.
Published: December 2012

This paper is concerned with the generalization of the concept of cotorsion abelian group. A locally compact abelian group

L

is called generalized cotorsion if

L

contains a compact open subgroup

K

such that the character group of

K

and the group

L/K

are cotorsion groups. Some properties and homological characteristics of generalized cotorsion groups are obtained. The classification problem of generalized cotorsion groups is discussed.
Airborne observations of aerosol microphysical properties and particle ageing processes in the troposphere above Europe
Authors: Hamburger T. , McMeeking G. , Minikin A. , Petzold A. , Coe H. , Krejci R.
Published: December 2012

Abstract. In-situ measurements of aerosol microphysical properties were performed in May 2008 during the EUCAARI-LONGREX campaign. Two aircraft, the FAAM BAe-146 and DLR Falcon 20, operated from Oberpfaffenhofen, Germany. A comprehensive data set was obtained comprising the wider region of Europe north of the Alps throughout the whole tropospheric column. Prevailing stable synoptic conditions enabled measurements of accumulating emissions inside the continental boundary layer reaching a maximum total number concentration of 19 000 particles cm−3 stp. Ultra-fine particles as indicators for nucleation events were observed within the boundary layer during high pressure conditions and after updraft of emissions induced by frontal passages above 8 km altitude in the upper free troposphere. Aerosol ageing processes during air mass transport are analysed using trajectory analysis. The ratio of particles containing a non-volatile core (250 °C) to the total aerosol number concentration was observed to increase within the first 12 to 48 h from the particle source from 50 to 85% due to coagulation. Aged aerosol also features an increased fraction of accumulation mode particles of approximately 40% of the total number concentration. The presented analysis provides an extensive data set of tropospheric aerosol microphysical properties on a continental scale which can be used for atmospheric aerosol models and comparisons of satellite retrievals.
Estimation of aerosol particle number distributions with Kalman Filtering – Part 1: Theory, general aspects and statistical validity
Authors: Viskari T. , Asmi E. , Kolmonen P. , Vuollekoski H. , Petäjä T. , Järvinen H.
Published: December 2012

Abstract. Aerosol characteristics can be measured with different instruments providing observations that are not trivially inter-comparable. Extended Kalman Filter (EKF) is introduced here as a method to estimate aerosol particle number size distributions from multiple simultaneous observations. The focus here in Part 1 of the work was on general aspects of EKF in the context of Differential Mobility Particle Sizer (DMPS) measurements. Additional instruments and their implementations are discussed in Part 2 of the work. University of Helsinki Multi-component Aerosol model (UHMA) is used to propagate the size distribution in time. At each observation time (10 min apart), the time evolved state is updated with the raw particle mobility distributions, measured with two DMPS systems. EKF approach was validated by calculating the bias and the standard deviation for the estimated size distributions with respect to the raw measurements. These were compared to corresponding bias and standard deviation values for particle number size distributions obtained from raw measurements by a inversion of the instrument kernel matrix method. Despite the assumptions made in the EKF implementation, EKF was found to be more accurate than the inversion of the instrument kernel matrix in terms of bias, and compatible in terms of standard deviation. Potential further improvements of the EKF implementation are discussed.
Selective measurements of isoprene and 2-methyl-3-buten-2-ol based on NO+ ionization mass spectrometry
Authors: Karl T. , Hansel A. , Cappellin L. , Kaser L. , Herdlinger-Blatt I. , Jud W.
Published: December 2012

Abstract. Biogenic VOC emissions are often dominated by 2-methyl-1,3-butadiene (isoprene) and 2-methyl-3-buten-2-ol (232 MBO). Here we explore the possibility to selectively distinguish these species using NO+ as a primary ion in a conventional PTR-MS equipped with an SRI unit. High purity of NO+ (>90%) as a primary ion was utilized in laboratory and field experiments using a conventional PTR-TOF-MS. Isoprene is ionized via charge transfer leading to the major product ion C5H8+ (>99%) (e.g. Spanel and Smith, 1998). 232 MBO undergoes a hydroxide ion transfer reaction resulting in the major product ion channel C5H9+ (>95%) (e.g. Amelynck et al., 2005). We show that both compounds are ionized with little fragmentation (>5%) under standard operating conditions. Typical sensitivities of 11.1 ± 0.1 (isoprene) and 12.9 ± 0.1 (232 MBO) ncps ppbv−1 were achieved, which correspond to limit of detections of 18 and 15 pptv respectively for a 10 s integration time. Sensitivities decreased at higher collisional energies. Calibration experiments showed little humidity dependence. We tested the setup at a field site in Colorado dominated by ponderosa pine, a 232 MBO emitting plant species. Our measurements confirm 232 MBO as the dominant biogenic VOC at this site, exhibiting typical average daytime concentrations between 0.2–1.4 ppbv. The method is able to detect the presence of trace levels of isoprene at this field site (90–250 ppt) without any interference from 232 MBO, which would not be feasible using H3O+ ionization chemistry, and which currently also remains a challenge for other analytical techniques (e.g. gas chromatographic methods).
Measurement of overall uptake coefficients for HO2 radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang (China)
Authors: Taketani F. , Kanaya Y. , Pochanart P. , Liu Y. , Li J. , Okuzawa K. , Kawamura K. , Wang Z. , Akimoto H.
Published: December 2012

Abstract. HO2 uptake coefficients for ambient aerosol particles, collected on quartz fiber filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol particles at the Mt. Tai site were ranged from 0.13 to 0.34, while those at the Mt. Mang site were in the range of 0.09–0.40. These values are generally larger than those previously reported for single-component particles, suggesting that reactions with the minor components such as metal ions and organics in the particle could contribute to the HO2 uptake. A box model calculation suggested that the heterogeneous loss of HO2 by ambient particles could significantly affect atmospheric HOx concentrations and chemistry.
Effects of biogenic nitrate chemistry on the NOx lifetime in remote continental regions
Authors: Browne E. C. , Cohen R. C.
Published: December 2012

Abstract. We present an analysis of the NOx budget in conditions of low NOx (NOx = NO + NO2) and high biogenic volatile organic compound (BVOC) concentrations that are characteristic of most continental boundary layers. Using a steady-state model, we show that below 500 pptv of NOx, the NOx lifetime is extremely sensitive to organic nitrate (RONO2) formation rates. We find that even for RONO2 formation values that are an order of magnitude smaller than is typical for continental conditions significant reductions in NOx lifetime, and consequently ozone production efficiency, are caused by nitrate forming reactions. Comparison of the steady-state box model to a 3-D chemical transport model (CTM) confirms that the concepts illustrated by the simpler model are a useful approximation of predictions provided by the full CTM. This implies that the regional and global budgets of NOx, OH, and ozone will be sensitive to assumptions regarding organic nitrate chemistry. Changes in the budgets of these species affect the representation of processes important to air quality and climate. Consequently, CTMs must include an accurate representation of organic nitrate chemistry in order to provide accurate assessments of past, present, and future air quality and climate. These findings suggest the need for further experimental constraints on the formation and fate of biogenic RONO2.
Dynamical characteristics of ice supersaturated regions
Authors: Gierens K. , Brinkop S.
Published: December 2012

Abstract. The typical distributions of dynamical fields within ice supersaturated regions are investigated. The dynamical fields divergence, relative vorticity, and vertical velocity are analysed statistically in two ways, namely using the unconditioned data and data conditioned on the presence of ice supersaturation. Two geographical regions are considered, namely Europe (250 hPa level) and the tropical belt from 30° S to 30° N on two pressure levels (200 and 150 hPa). The study is based on forecast data from the European Centre for Medium-Range Weather Forecasts for four months covering the four seasons, June, September, December 2011 and March 2012. We find that histograms (frequency distributions) and low order moments of the dynamical fields differ substantially and statistically significantly inside and outside of ice supersaturated regions. As expected, upward and divergent flow favours ice supersaturation. But we find also that ice supersaturation is mostly located in anti-cyclonic flow. The latter result is probably due to the structure of warm/moist and cold/dry air streams in synoptic disturbances in mid-latitudes, but probably merely coincidental in the tropical belt.
Asian dust storm observed at a rural mountain site in southern China: chemical evolution and heterogeneous photochemistry
Authors: Nie W. , Wang T. , Xue L. K. , Ding A. J. , Wang X. F. , Gao X. M. , Xu Z. , Yu Y. C. , Yuan C. , Zhou Z. S. , Gao R. , Liu X. H. , Wang Y. , Fan S. J. , Poon S. , Zhang Q. Z. , Wang W. X.
Published: December 2012

Abstract. Heterogeneous processes on dust particles are important for understanding the chemistry and radiative balance of the atmosphere. This paper investigates an intense Asian dust storm episode observed at Mount Heng (1269 m a.s.l.) in southern China on 24–26 April 2009. A set of aerosol and trace gas data collected during the study was analyzed to investigate their chemical evolution and heterogeneous photochemistry as the dust traveled to southern China. Results show that the mineral dust arriving at Mt. Heng experienced significant modifications during transport, with large enrichments in secondary species (sulfate, nitrate, and ammonium) compared with the dust composition collected at an upwind mountain top site (Mount Hua). A photochemical age "clock" (−Log10(NOx/NOy)) was employed to quantify the atmospheric processing time. The result indicates an obvious increase in the abundance of secondary water-soluble ions in dust particles with the air mass atmospheric processing time. Based on the observations, a 4-stage evolution process is proposed for carbonate-containing Asian dust, starting from fresh dust to particles coated with hydrophilic and acidic materials. Daytime-enhanced nitrite formation on the dust particles was also observed, which indicates the recent laboratory result of the TiO2 photocatalysis of NO2 as a potential source of nitrite and nitrous acid.
Observation of horizontal winds in the middle-atmosphere between 30° S and 55° N during the northern winter 2009–2010
Authors: Baron P. , Murtagh D. P. , Urban J. , Sagawa H. , Ochiai S. , Körnich H. , Khosrawi F. , Kikuchi K. , Mizobuchi S. , Sagi K. , Kasai Y. , Yasui M.
Published: December 2012

Abstract. Although the links between stratospheric dynamics, climate and weather have been demonstrated, direct observations of stratospheric winds are lacking. We report observations of winds between 8 and 0.01 hPa (~35–80 km) from October 2009 to April 2010 by the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) on the International Space Station. The altitude range covers the region between 35–60 km where previous space-borne wind instruments show a lack of sensitivity. Both zonal and meridional wind components were obtained, though not simultaneously, in the latitude range from 30° S to 55° N and with a single profile precision of 7–9 m s−1 between 8 and 0.6 hPa and better than 20 m s−1 at altitudes above. The vertical resolution is 5–7 km except in the upper part of the retrieval range (10 km at 0.01 hPa). In the region between 1–0.05 hPa, a mean difference <2 m s−1 is found between SMILES profiles retrieved from different spectroscopic lines and instrumental settings. Good agreement (mean difference of ~2 m s−1) is also found with the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis in most of the stratosphere except for the zonal winds over the equator (mean difference of 5–10 m s−1). In the mesosphere, SMILES and ECMWF zonal winds exhibit large differences (> 20 m s−1), especially in the tropics. We illustrate our results by showing daily and monthly zonal wind variations, namely the semi-annual oscillation in the tropics and reversals of the flow direction between 50° N–55° N during sudden stratospheric warmings in the stratosphere. The daily comparison with ECMWF winds reveals that in the beginning of February, a significantly stronger zonal westward flow is measured in the tropics at 2 hPa compared to the flow computed in the analysis (difference of ~20 m s−1). The results show that the comparison between SMILES and ECMWF winds is not only relevant for the quality assessment of the new SMILES winds but it also provides insights on the quality of the ECMWF winds themselves. Although the instrument was not specifically designed for measuring winds, the results demonstrate that space-borne sub-mm wave radiometers have the potential to provide good quality data for improving the stratospheric winds in atmospheric models.
Influence of increasing dissolved inorganic carbon concentrations and decreasing pH on chemolithoautrophic bacteria from oxic-sulfidic interfaces
Authors: Mammitzsch K. , Jost G. , Jürgens K.
Published: December 2012

Abstract. Increases in the dissolved inorganic carbon (DIC) concentration are expected to cause a decrease in the pH of ocean waters, a process known as ocean acidification. In oxygen-deficient zones this will add to already increased DIC and decreased pH values. It is not known how this might affect microbial communities and microbially mediated processes. In this study, the potential effects of ocean acidification on chemolithoautotrophic prokaryotes of marine oxic-anoxic transition zones were investigated, using the chemoautotrophic denitrifying ε-proteobacterium "Sulfurimonas gotlandica" strain GD1 as a model organism. This and related taxa use reduced sulfur compounds, e.g. sulfide and thiosulfate, as electron donors and were previously shown to be responsible for nitrate removal and sulfide detoxification in redox zones of the Baltic Sea water column but occur also in other oxygen-deficient marine systems. Bacterial cell growth within a broad range of DIC concentrations and pH values was monitored and substrate utilization was determined. The results showed that the DIC saturation concentration for growth was already reached at 800 μM, which is well below in situ DIC levels. The pH optimum was between 6.6 and 8.0. Within a pH range of 6.6–7.1 there was no significant difference in substrate utilization; however, at lower pH values cell growth decreased sharply and cell-specific substrate consumption increased. These findings suggest that a direct effect of ocean acidification, with the predicted changes in pH and DIC, on chemolithoautotrophic bacteria such as "S. gotlandica" str. GD1 is generally not very probable.
Elevation correction of ERA-Interim temperature data in complex terrain
Authors: Gao L. , Bernhardt M. , Schulz K.
Published: December 2012

Abstract. Air temperature controls a large variety of environmental processes, and is an essential input parameter for land surface models, for example in hydrology, ecology and climatology. However, meteorological networks, which can provide the necessary information, are commonly sparse in complex terrains, especially in high mountainous regions. In order to provide temperature data in an adequate temporal and spatial resolution for local scale applications a new elevation correction method has been developed that is able to downscale 3-hourly ERA-Interim temperature data. The scheme is based on model internal vertical lapse rates derived from different ERA-Interim pressure levels and has been validated for twelve meteorological stations in the German and Swiss Alps. The method was also compared with two other statistical, lapse rate based correction approaches. The results indicate that the use of model internal ERA-Interim lapse rates can significantly improve the downscaling performance when compared to the standard procedure of using fixed lapse rates.
Development and implementation of a GIS-based tool for spatial modeling of seismic vulnerability of Tehran
Authors: Hashemi M. , Alesheikh A. A.
Published: December 2012

Abstract. Achieving sustainable development in countries prone to earthquakes is possible with taking effective measures to reduce vulnerability to earthquakes. In this context, damage assessment of hypothetical earthquakes and planning for disaster management are important issues. Having a computer tool capable of estimating structural and human losses from earthquakes in a specific region may facilitate the decision-making process before and during disasters. Interoperability of this tool with wide-spread spatial analysis frameworks will expedite the data transferring process. In this study, the earthquake damage assessment (EDA) software tool is developed as an embedded extension within a GIS (geographic information system) environment for the city of Tehran, Iran. This GIS-based extension provides users with a familiar environment to estimate and observe the probable damages and fatalities of a deterministic earthquake scenario. The productivity of this tool is later demonstrated for southern Karoon parish, Region 10, Tehran. Three case studies for three active faults in the area and a comparison of the results with other research substantiated the reliability of this tool for additional earthquake scenarios.
Comparative Effects of Three Iron Chelation Therapies on the Quality of Life of Greek Patients with Homozygous Transfusion-Dependent Beta-Thalassemia
Authors: Goulas Vasilis , Kourakli-Symeonidis Alexandra , Camoutsis Charalambos
Published: December 2012

This prospective study assessed the quality of life of patients with homozygous transfusion-dependent beta-thalassemia in Greece receiving three different iron chelation treatments. Patients enrolled were receiving one of the following chelation therapies: deferoxamine (n=21), deferasirox (n=75), or deferoxamine in combination with deferiprone (n=39). The three groups were compared in terms of their quality of life, satisfaction and adherence to treatment, control of their health, and self-esteem through the completion of five questionnaires. A higher percentage of patients receiving deferoxamine felt that their treatment negatively influenced their body and skin appearance and limited their ability to work, attend school, and perform daily tasks (P=0.0066). The adherence to treatment rate and self-esteem were the lowest in the deferoxamine group (P<0.05). The deferoxamine group also had the lowest physical component summary score in the SF-36 questionnaire (P=0.014). This study suggests that the quality of life of beta-thalassemia patients receiving chelation therapy is dependent on the type of iron chelation treatment they receive. The study provides insight into important factors associated with the quality of life of these patients, which are essential for developing a more suitable clinical support team and counseling in order to maximize the treatment benefits for these patients in daily clinical practice.
Gender, Work, and Health for Trans Health Providers: A Focus on Transmen
Authors: MacDonnell Judith A. , Grigorovich Alisa
Published: December 2012

Well-documented health research points to trans people’s vulnerability to health inequities that are linked to deeply embedded structural and social determinants of health. Gender and work, as social determinants of health for trans people, both shape and are shaped by multiple factors such as support networks, social environments, income and social status, shelter, and personal health practices. There is a gap in the nursing literature in regards to research on work and health for diverse trans people and a virtual silence on the particular issues of trans-identified health providers. This qualitative study used comparative life history methodology and purposeful sampling to examine links among work, career, and health for transmen who are health providers. Semistructured interviews were completed with four Canadian transmen involved in health care professional and/or practice contexts with diverse professions, age, work, and transitioning experiences. Critical gender analysis showed that unique and gender-related critical events and influences shape continuities and discontinuities in their careerlives. This strength-based approach foregrounds how resilience and growth emerged through participants’ articulation with everyday gender dynamics. These findings have implications for nursing research, education, and practice that include an understanding of how trans providers “do transgender work” and supporting them in that process.
Biological Markers and Response to Neoadjuvant Taxane-Based Chemotherapy in Patients with Locally Advanced Breast Cancer
Authors: El-sayed Mohamed I. , Maximous Doaa W. , Zakhary Madeha M. , Mikhail Nabiel N. H.
Published: December 2012

Introduction. Biological markers as Her2/neu, p53, and hormonal receptors (HmRs) may be reliable parameters for prognostic assessment of patients of locally advanced breast cancer (LABC). This work aims at assessing the potential value of these biological markers for the prediction of disease outcome after neoadjuvant taxane-based chemotherapy and its implication on the surgical role.Patients and Methods. From March 2006 to September 2011, 95 patients with LABC were treated by neoadjuvant taxane-based chemotherapy given at intervals of 3 weeks. Expression of Her2/neu and p53 was examined in the initial tissue biopsy by using ELISA technique. Status of HmRs was determined using a commercial enzyme immunoassay. Three weeks after the third cycle, patients underwent surgical resection followed by 3 more cycles of taxane-based chemotherapy and radiotherapy as an adjuvant therapy. Relations of Her2/neu overexpression to p53, HmRs, and conventional prognostic factors were analyzed.Results. Median followup was 61 months. The 5-year DFS and OAS rates were significantly higher in patients with positive HmRs than in those with negative HmRs, patients with Her2− than those with Her2+ breast cancer, and patients with intact p53 breast cancer than those with inactive p53. HER-2 overexpression was statistically significant associated with loss of HmR positive immunostaining (), grade III breast cancer (), advanced nodal status (), and younger (<50 years) age ().Conclusion. Her2/neu overexpression was associated with poor DFS and OAS rates, as it was significantly associated with negative HmR and high grade.
Feedback Control in Quantum Optics: An Overview of Experimental Breakthroughs and Areas of Application
Authors: Serafini Alessio
Published: December 2012

We present a broad summary of research involving the application of quantum feedback control techniques to optical setups, from the early enhancement of optical amplitude squeezing to the recent stabilisation of photon number states in a microwave cavity, dwelling mostly on the latest experimental advances. Feedback control of quantum optical continuous variables, quantum nondemolition memories, feedback cooling, quantum state control, adaptive quantum measurements, and coherent feedback strategies will all be touched upon in our discussion.
Theoretical Evaluation of Ultrasonic Velocities in Binary Liquid Mixtures of Anisaldehyde with Some Alcoxyethanols at Different Temperatures
Authors: Begum Zareena , Sandhya Sri P. B. , Rambabu C.
Published: December 2012

Ultrasonic velocities and densities of the binary liquid mixtures of anisaldehyde with alcoxyethanols like methoxyethanol (MOE), ethoxyethanol (EOE), and butoxyethanol (BOE) have been measured at temperatures 303.15 K, 308.15 K, 313.15 K, and 318.15 K over the entire composition range of mole fractions. The theoretical values of ultrasonic velocity were evaluated using Nomoto's relation (), impedance relation (), ideal mixing relation (), Jungie's relation (), and Rao’s specific velocity relation (). The molecular interaction parameter () has been evaluated from the values of experimental and theoretical velocities. The variation of this interaction parameter with the composition mixture has been discussed in terms of molecular interactions.