bluuebunny/crossref_metadata_2025 huggingface dataset:
Convergence assessment of numerical Monte Carlo simulations in groundwater hydrology
Authors: Ballio Francesco , Guadagnini Alberto
Published: April 2004

Numerical Monte Carlo simulation is considered to be one of the main tools to be used in groundwater hydrology (1) to quantify the uncertainty in the flow predictions due to imperfect knowledge of aquifer architecture, hydraulic parameters, and forcing terms or (2) to assess the reliability of approximated moment‐based equations for flow and/or transport. While the Monte Carlo framework is conceptually straightforward and very flexible, it is recognized as lacking well‐established convergence criteria. Here we propose a methodology for convergence analysis of Monte Carlo simulations and therefore for the reliability assessment of the inferred statistical moments. The methodology, based on simple rules of statistical inference, is described with reference to a typical groundwater flow problem and can be extended to different application fields.
A triggered lightning flash containing both negative and positive strokes
Authors: Jerauld J. , Uman M. A. , Rakov V. A. , Rambo K. J. , Jordan D. M.
Published: April 2004

We present measured current, luminosity, and electric and magnetic fields for a rocket‐triggered two‐stroke flash. The first stroke lowered negative charge to ground and the second stroke lowered positive charge via the same channel. A triggered positive stroke is a very rare event. The measured negative return stroke peak current was −11 kA and the positive +5 kA, with the total charge transfers being −1 C and +24 C, respectively. Electric field measurements at 120 to 520 m indicate that the negative and positive dart leader charge densities were approximately constant with height, −7.2 × 10−5 C m−1 and +5.5 × 10−5 C m−1, respectively. Magnetic field measurements indicate a negative leader current of −1.9 kA and a positive leader current of +400 A. Negative and positive dart‐leader speeds are estimated to be 2.7 × 107 m s−1 and 0.7 × 107 m s−1, respectively. Negative and positive return stroke speeds are estimated to be 1.6 × 108 and 0.92 × 108 m s−1, respectively.
Motion partitioning between the Pacific plate, Baja California and the North America plate: The Tosco‐Abreojos fault revisited
Authors: Michaud F. , Sosson M. , Royer J.‐Y. , Chabert A. , Bourgois J. , Calmus T. , Mortera C. , Bigot‐Cormier F. , Bandy W. , Dyment J. , Pontoise B. , Sichler B.
Published: April 2004

During the FAMEX cruise of the R/V L'Atalante (April 2002), swath bathymetry and seismic profiles were recorded along the Baja California margin from 23° to 27°N. The upper‐slope of the margin exhibits active faulting of recent sediments along the Tosco‐Abreojos fault system (TAFS). Flower structures evidence strike‐slip motion along the TAFS. Right lateral strike slip faulting, associated in places with small extensional features, are consistent with present‐day slip and extension rates predicted along the TAFS. The TAFS thus belongs to the western active boundary of a Baja California Block yet not totally transferred to the Pacific plate.
Corporate strategy revisited: a view from complexity theory
Authors: Caldart Adrián Atilio , Ricart Joan Enric
Published: April 2004

Abstract Despite its long tradition and well‐known contributions, corporate strategy research is yet far from being mature. This paper proposes an innovative framework that approaches the field from the theoretical perspective provided by complexity theory. We propose to see the corporate level of the organization as the driver, pacer and framer of the overall firm's evolution process. Drive is provided by the cognitive representation of the corporate fitness landscape that is implicit in the firm's corporate plan. Pacing is a consequence of the kind of strategic initiatives (‘search strategy’) developed by the company. Framing is achieved through the architectural design that the corporate level implements for the firm.
The millennium nexus: Strategic management at the cross‐roads
Authors: McKiernan Peter , Carter Chris
Published: April 2004

Abstract This editorial essay introduces each of the articles contained in this inaugural issue of the European Management Review. The articles fall into two broad categories: the first group engages with arguments around ‘strategy‐as‐practice’, a perspective that is gaining increasing prominence within strategic management; the second group of papers are best understood as acting as cultural intermediaries, in that they bring fresh insights from other subjects to the study of strategic management.
Tob deficiency superenhances osteoblastic activity after ovariectomy to block estrogen deficiency-induced osteoporosis
Authors: Usui Michihiko , Yoshida Yutaka , Tsuji Kunikazu , Oikawa Kaoru , Miyazono Kohei , Ishikawa Isao , Yamamoto Tadashi , Nifuji Akira , Noda Masaki
Published: April 2004

Tob (transducer of erbB2) is a member of antiproliferative family proteins and acts as a bone morphogenic protein inhibitor as well as a suppressor of proliferation in T cells, which have been implicated in postmenopausal bone loss. To determine the effect of Tob deficiency on estrogen deficiency-induced bone loss, we analyzed bone metabolism after ovariectomy or sham operation in Tob-deficient mice. Ovariectomy in WT mice decreased trabecular bone volume and bone mineral density (BMD) as expected. In Tob-deficient mice, ovariectomy reduced bone volume and BMD. However, even after ovariectomy, both trabecular bone volume and BMD levels in Tob-deficient bone were comparable to those in sham-operated WT bones. Bone formation parameters (mineral apposition rate and bone formation rate) in the ovariectomized Tob-deficient mice were significantly higher than those in the ovariectomized WT mice. In contrast, the ovariectomy-induced increase in the bone resorption parameters, osteoclast surface, and osteoclast number was similar between Tob-deficient mice and WT mice. Furthermore, in
ex vivo
nodule formation assay, ovariectomy-induced enhancement of nodule formation was significantly higher in the bone marrow cells from Tob-deficient mice than in the bone marrow cells from ovariectomized WT mice. Both Tob and estrogen signalings converge at bone morphogenic protein activation of alkaline phosphatase and GCCG-reporter gene expression in osteoblasts, revealing interaction between the two signals. These data indicate that Tob deficiency prevents ovariectomy-induced bone loss through the superenhancement of osteoblastic activities in bone and that this results in further augmentation in the bone formation rate and the mineral apposition rate after ovariectomy
in vivo
.
Theoretical basis for genetic linkage analysis in autotetraploid species
Authors: Luo Z. W. , Zhang R. M. , Kearsey M. J.
Published: April 2004

Linkage analysis in autotetraploid species has been an historical challenge in quantitative genetics theory and is a stumbling block that urgently needs to be removed in the rapidly emerging genome research on this species, such as cultivated potato. This article presents theory of a full model of tetrasomic linkage and develops a statistical framework for the linkage analysis. The model considers both double reduction and recombination, the most essential features of tetrasomic inheritance with linked loci, whereas the statistical method takes appropriate account of the major complexities in analyzing both dominant and codominant molecular marker data during map reconstruction in tetraploid species. These complexities include the problems arising from multiple dosage of allelic inheritance, the null allele, allelic segregation distortion, mixed bivalent and quadrivalent pairing in meiosis, and incomplete information of marker phenotype data. The theoretical analysis established the relationship between the coefficients of double reduction at linked loci, which is essential in the present tetrasomic linkage analysis and in assessing the impact of double reduction on the evolution of tetraploid populations. The statistical method, based on the combination of theoretical analysis and a computer-based algorithm, provided analytical tools for predicting the maximum-likelihood estimates of the model parameters. A simulation study showed the feasibility of a practical implementation of the method, detailed the procedure of the analysis, validated the power and reliability in the parameter estimation, and compared the present method with those proposed in the current literature.
Membrane-associated guanylate kinase-like properties of β-subunits required for modulation of voltage-dependent Ca
2+
channels
Authors: Takahashi Shoji X. , Miriyala Jayalakshmi , Colecraft Henry M.
Published: April 2004

High-voltage-activated Ca
2+
channels regulate diverse functions ranging from muscle contraction to synaptic transmission. Association between auxiliary β- and distinct pore-forming α
1
-subunits is obligatory for forming functional high-voltage-activated Ca
2+
channels, yet the structural determinants underlying this interaction remain poorly understood. Recently, homology modeling of Ca
2+
-channel β
1b
-subunit identified
src
homology 3 (SH3) and guanylate kinase (GK) motifs in a tandem arrangement reminiscent of the membrane-associated guanylate kinase (MAGUK) class of scaffolding proteins. However, direct evidence for MAGUK-like properties and their functional implications in β-subunits is lacking. Here, we show a functional requirement for both SH3 and GK domains in β
2a
. Point mutations in either the putative β
2a
SH3 or GK domains severely blunted modulation of recombinant L-type channels, showing the importance of both motifs for a functional α
1
–β interaction. Coexpression of these functionally deficient β
2a
-SH3 and GK mutants rescued WT currents, demonstrating trans complementation similar to that observed in MAGUKs. Truncated “hemi-β
2a
” subunits, containing either the SH3 or GK domain, were ineffective on their own, but reconstituted WT currents when coexpressed. Moreover, the SH3 and GK domains were found to interact
in vitro
. These findings reveal MAGUK-like properties in β-subunits that are critical for α
1
-subunit modulation, revise current models of α
1
–β association, and predict new physiological dimensions of β-subunit function.
Matefin, a
Caenorhabditis elegans
germ line-specific SUN-domain nuclear membrane protein, is essential for early embryonic and germ cell development
Authors: Fridkin Alexandra , Mills Erez , Margalit Ayelet , Neufeld Esther , Lee Kenneth K. , Feinstein Naomi , Cohen Merav , Wilson Katherine L. , Gruenbaum Yosef
Published: April 2004

Caenorhabditis elegans mtf-1
encodes matefin, which has a predicted SUN domain, a coiled-coil region, an anti-erbB-2 IgG domain, and two hydrophobic regions. We show that matefin is a nuclear membrane protein that colocalizes
in vivo
with Ce-lamin, the single nuclear lamin protein in
C. elegans
, and binds Ce-lamin
in vitro
but does not require Ce-lamin for its localization. Matefin is detected in all embryonic cells until midembryogenesis and thereafter only in germ-line cells. Embryonic matefin is maternally deposited, and matefin is the first nuclear membrane protein known to have germ line-restricted expression. Animals homozygous for an
mtf-1
deletion allele show that matefin is essential for germ line maturation and survival. However, matefin is also required for embryogenesis because
mtf-1 (RNAi)
embryos die around the ≈300-cell stage with defects in nuclear structure, DNA content, and chromatin morphology. Down-regulating matefin in
mes-3
animals only slightly enhances embryonic lethality, and elimination of UNC-84, the only other SUN-domain gene in
C. elegans
, has no affect on
mtf-1 (RNAi)
animals. Thus,
mtf-1
mediates a previously uncharacterized pathway(s) required for embryogenesis as well as germ line proliferation or survival.
Experimentally exploring the conformational space sampled by domain reorientation in calmodulin
Authors: Bertini Ivano , Del Bianco Cristina , Gelis Ioannis , Katsaros Nikolaus , Luchinat Claudio , Parigi Giacomo , Peana Massimiliano , Provenzani Alessandro , Zoroddu Maria Antonietta
Published: April 2004

The conformational space sampled by the two-domain protein calmodulin has been explored by an approach based on four sets of NMR observables obtained on Tb
3+
- and Tm
3+
-substituted proteins. The observables are the pseudocontact shifts and residual dipolar couplings of the C-terminal domain when lanthanide substitution is at the N-terminal domain. Each set of observables provides independent information on the conformations experienced by the molecule. It is found that not all sterically allowed conformations are equally populated. Taking the N-terminal domain as the reference, the C-terminal domain preferentially resides in a region of space inscribed in a wide elliptical cone. The axis of the cone is tilted by ≈30° with respect to the direction of the N-terminal part of the interdomain helix, which is known to have a flexible central part in solution. The C-terminal domain also undergoes rotation about the axis defined by the C-terminal part of the interdomain helix. Neither the extended helix conformation initially observed in the solid state for free calcium calmodulin nor the closed conformation(s) adopted by calcium calmodulin either alone or in its adduct(s) with target peptide(s) is among the most preferred ones. These findings are unique, both in terms of structural information obtained on a biomolecule that samples multiple conformations and in terms of the approach developed to achieve the results. The same approach is in principle applicable to other multidomain proteins, as well as to multiple interaction modes between two macromolecular partners.
Genomic analysis of the host response to hepatitis B virus infection
Authors: Wieland Stefan , Thimme Robert , Purcell Robert H. , Chisari Francis V.
Published: April 2004

Previous studies in hepatitis B virus (HBV)-infected humans and chimpanzees suggest that control of HBV infection involves the cells, effector functions, and molecular mediators of the immune response. The objective of the current study was to identify, in the liver of acutely HBV-infected chimpanzees, the spectrum of virus-induced and immune response-related genes that regulate the infection. The results demonstrate that HBV does not induce any genes during entry and expansion, suggesting it is a stealth virus early in the infection. In contrast, a large number of T cell-derived IFN-γ-regulated genes are induced in the liver during viral clearance, reflecting the impact of an adaptive T cell response that inhibits viral replication and kills infected cells, thereby terminating the infection.
Cultural Clusters and the Post-industrial City: Towards the Remapping of Urban Cultural Policy
Authors: Mommaas Hans
Published: April 2004

This paper explores and discusses the fairly recent phenomenon of cultural clustering strategies in the Netherlands. Amongst other things based on ideologies of 'enterprise culture', the quest for urban imagery and positioning strategies, the changing spatial fabric of cities and a search for economic and cultural revitalisation, for the past 5-10 years, the formation of cultural clusters has turned into something of an urban cultural development hype. However, what at first glance appears as a common model, often accompanied by boldly expressed slogans concerning the new role of culture and creativity in the physical and economic revitalisation of cities, in more detail unfolds as an ambivalent and conflict-ridden mixture of cultural, economic, social and spatial interests and sentiments. From a short-term perspective, such an eclectic blending of interests and sentiments might be considered as a good opportunity for urban cultural developments within a 'post-modern' urban development regime. However, from a long-term perspective, there is the danger that the divergent sentiments and interests start to undermine and constrain each other, in the end resulting in adverse effects, mutual distrust and a standstill of developments. Following a detailed investigation of five cultural clustering projects in the Netherlands, and based on Zukin's account of the exchange of cultural and economic values in the contemporary city, the paper argues that, in order to get out of this potentially self-defeating situation, and to enable a more sensitive but also strategic involvement of the cultural sector in the governance of cultural cluster projects, it is necessary to develop a more sophisticated understanding of the complex dynamics involved. Central to this is a locally specific appreciation of the changing interaction between culture (place) and commerce (market) in today's mixed economy of leisure, culture and creativity. This implies both a critique and advancement of existing theories concerning the role of culture in urban development and the development of a more detailed comparative perspective on urban cultural policy projects, thus moving beyond overgeneralised perceptions of the developments concerned.
Policies for Urban Form and their Impact on Travel: The Netherlands Experience
Authors: Schwanen Tim , Dijst Martin , Dieleman Frans M.
Published: April 2004

This paper documents an evaluation of the consequences of the Netherlands national physical planning policy for an individual's travel behaviour. Four components of this policy are considered: the concentrated decentralisation of the 1970s and 1980s; the strict compact-city policy of the 1980s and 1990s; the A-B-C location policy; and the spatial retailing policy. Using data from the 1998 Netherlands National Travel Survey, the article addresses the following questions. Did physical planning reduce the use of the private car and promote the use of public transport together with cycling and walking? Did physical planning lead to shorter travel distances and times? The analysis suggests that national spatial planning has been most effective in retaining high shares of cycling and walking in the large and medium-sized cities, in particular for shopping trips. In terms of travel time, however, spatial policy seems to have been less successful. The building of new towns and, more recently, the development of greenfield neighbourhoods close to cities do not appear to have reduced commuting times. Alternative strategies to promote the use of public transport, the bicycle and walking through the regulation of land use are discussed. Relaxing some of the present spatial planning controls is suggested to reduce car use and travel times.
Husayn Vaᶜiz-i Kashifi: Polymath, Popularizer, and Preserver
Authors: Subtelny Maria E.
Published: April 2004

This issue of Iranian Studies is Devoted to the Late Medieval Persian Preacher and polymath, Kamal al-Din Husayn b. ᶜAli Vaᶜiz-i Kashifi, and it coincides roughly with the quincentenary of his death in 910/1504–05. It is based on a panel of papers delivered at the Fourth Biennial Conference on Iranian Studies, which was held in Bethesda, Maryland, May 24–26, 2002, under the sponsorship of the Society for Iranian Studies, and co-sponsorship of the Association for the Study of Persianate Societies. It brings together papers on a number of Husayn Kashifi's works with the aim of demonstrating the breadth of his oeuvre, and in particular his contribution to the codification, primarily in Persian, of knowledge in fields covering the entire spectrum of learning in medieval Iran at the turn of the sixteenth century. As such, the volume seeks to “rehabilitate” Kashifi, who has usually been regarded merely as a compiler or popularizer, and to present him as a figure who was instrumental in the preservation and transmission of the state of the art of knowledge in a wide variety of fields in late medieval Iran.
Use of GHB Compounds by HIV‐Positive Individuals
Authors: Camacho Alvaro , Matthews Scott C. , Dimsdale Joel E.
Published: April 2004

Gamma hydroxybutyrate (GHB) has been used by body‐builders to enhance performance and by young adults in rave parties. Warnings have been posted about its addictive potential. The use of these dietary compounds is currently banned by the Food and Drug Administration, but they are widely available through the Internet and in certain communities. The purpose of the study was to examine the use of these compounds by HIV‐positive individuals and to investigate their knowledge of the addictive potential of GHB and its related dietary compounds. One hundred HIV‐positive individuals from the UCSD outpatient HIV clinic responded to an anonymous survey that inquired about their knowledge, use, and effects produced by GHB containing dietary compounds. The most common reported dietary compound beside GHB was Growth Hormone Release Extract (GHRE). Fifty‐two percent of individuals reported using at least one GHB containing dietary compound. Gay subjects reported the highest use of GHB compounds (76.9%; p ≤ 0.001). The most common effect reported by users was increased energy (71%). Only 24% of the total responders knew about GHB's addictive potential. Among reported users of GHB containing compounds, fourteen (27%) knew about its addictive potential and nine (17%) knew that the compound is illegal. This study shows that HIV‐positive gay individuals attending our clinic are using GHB compounds. Reported GHB users have limited knowledge about its addictive potential and serious adverse effects. More controlled studies are needed to evaluate long‐term effects of dietary compounds containing GHB, especially among HIV‐positive individuals who are actively receiving antiretroviral treatment. (Am J Addict 2004;13:120–127)
Borsuk-Ulam type theorems for compact Lie group actions
Authors: Hara Yasuhiro , Minami Norihiko
Published: April 2004

Borsuk-Ulam type theorems for arbitrary compact Lie group actions are proven. The transfer plays a major role in this approach.
A note on Kneser-Haken finiteness
Authors: Bachman David
Published: April 2004

Kneser-Haken finiteness asserts that for each compact 3-manifold

M
M

there is an integer

c
(
M
)

c(M)

such that any collection of

k
>
c
(
M
)

k>c(M)

closed, essential, 2-sided surfaces in

M
M

must contain parallel elements. We show here that if

M
M

is closed, then twice the number of tetrahedra in a (pseudo)-triangulation of

M
M

suffices for

c
(
M
)

c(M)

.
Operators with eigenvalues and extreme cases of stability
Authors: Downey Larry , Enflo Per
Published: April 2004

In the following, we consider some cases where the point spectrum of an operator is either very stable or very unstable with respect to small perturbations of the operator. The main result is about the shift operator on

l
2

,

l_2,

whose point spectrum is what we will call strongly stable. We also give some general perturbation results, including a result about the size of the set of operators that have an eigenvalue.
Asymptotics for the multiplicities in the cocharacters of some PI-algebras
Authors: Benanti Francesca , Giambruno Antonio , Sviridova Irina
Published: April 2004

We consider associative PI-algebras over a field of characteristic zero. We study the asymptotic behavior of the sequence of multiplicities of the cocharacters for some significant classes of algebras. We also give a characterization of finitely generated algebras for which this behavior is linear or quadratic.
Nevanlinna–Pick interpolation: Pick matrices have bounded number of negative eigenvalues
Authors: Bolotnikov V. , Kheifets A. , Rodman L.
Published: April 2004

The Nevanlinna–Pick interpolation problem is studied in the class of functions defined on the unit disk without a discrete set, with the property that all their Pick matrices have not more than a prescribed number of negative eigenvalues. It is shown, in particular, that the degenerate problem always has a unique solution, not necessarily meromorphic. A related extension problem to a maximal function in the class is also studied.
The backward shift on the space of Cauchy transforms
Authors: Cima Joseph , Matheson Alec , Ross William
Published: April 2004

This note examines the subspaces of the space of Cauchy transforms of measures on the unit circle that are invariant under the backward shift operator

f
→

z

−
1

(
f
−
f
(
0
)
)

f \to z^{-1}(f - f(0))

. We examine this question when the space of Cauchy transforms is endowed with both the norm and weak

∗

{}^*

topologies.
A remark to a theorem of Yu. A. Abramovich
Authors: Emel’yanov Eduard
Published: April 2004

A remarkable theorem due to Abramovich (1988) states that any surjective positive isometry on a Banach lattice has a positive inverse. In this note we discuss a renorming problem for Banach lattices and show that the theorem cannot be generalized to the case of the doubly power bounded positive operators.
Enclosure results for second-order relative spectra by elementary means
Authors: Otte Peter
Published: April 2004

Motivated by the general approach due to Shargorodsky we derive enclosure results for the second-order relative spectrum of bounded selfadjoint operators by studying quadratic operator pencils. The quality of the results is discussed by means of a simple example.
On invariability of self-injective algebras of tilted type under stable equivalences
Authors: Skowroński Andrzej , Yamagata Kunio
Published: April 2004

We prove that a large class of self-injective algebras of tilted type is invariant under stable equivalences of module categories.
Refining the constant in a maximum principle for the Bergman space
Authors: Wang Chunjie
Published: April 2004

Let

A
2

(

D

)

A^2(\mathbb {D})

be the Bergman space over the open unit disk

D

\mathbb {D}

in the complex plane. Korenblum conjectured that there is an absolute constant

c
,
 
0
>
c
>
1

c,~0>c>1

, such that whenever

|

f
(
z
)

|

≤

|

g
(
z
)

|

|f(z)|\leq |g(z)|

(

f
,
g
∈

A
2

(

D

)

f,g\in A^2(\mathbb {D})

) in the annulus

c
>

|

z

|

>
1

c>|z|>1

, then

‖
f
‖
≤
‖
g
‖

\|f\|\leq \|g\|

. In this note we give an example to show that

c
>
0.69472.

c>0.69472.
On injective or dense-range operators leaving a given chain of subspaces invariant
Authors: Yahaghi Bamdad
Published: April 2004

In this paper we prove the existence of dense-range or one-to-one compact operators on a separable Banach space leaving a given finite chain of subspaces invariant. We use this result to prove that a semigroup

S

\mathcal {S}

of bounded operators is reducible if and only if there exists an appropriate one-to-one compact operator

K
K

such that the collection

S

K

\mathcal {S} K

of compact operators is reducible.
A negative answer to Nevanlinna’s type question and a parabolic surface with a lot of negative curvature
Authors: Benjamini Itai , Merenkov Sergei , Schramm Oded
Published: April 2004

Consider a simply-connected Riemann surface represented by a Speiser graph. Nevanlinna asked if the type of the surface is determined by the mean excess of the graph: whether mean excess zero implies that the surface is parabolic, and negative mean excess implies that the surface is hyperbolic. Teichmüller gave an example of a hyperbolic simply-connected Riemann surface whose mean excess is zero, disproving the first of these implications. We give an example of a simply-connected parabolic Riemann surface with negative mean excess, thus disproving the other part. We also construct an example of a complete, simply-connected, parabolic surface with nowhere positive curvature such that the integral of curvature in any disk about a fixed basepoint is less than

−
ϵ

-\epsilon

times the area of disk, where

ϵ
>
0

\epsilon >0

is some constant.
Differentiability of cone-monotone functions on separable Banach space
Authors: Borwein Jonathan , Burke James , Lewis Adrian
Published: April 2004

Motivated by applications to (directionally) Lipschitz functions, we provide a general result on the almost everywhere Gâteaux differentiability of real-valued functions on separable Banach spaces, when the function is monotone with respect to an ordering induced by a convex cone with non-empty interior. This seemingly arduous restriction is useful, since it covers the case of directionally Lipschitz functions, and necessary. We show by way of example that most results fail more generally.
Approximation in reflexive Banach spaces and applications to the invariant subspace problem
Authors: Chalendar Isabelle , Partington Jonathan , Smith Martin
Published: April 2004

We formulate a general approximation problem involving reflexive and smooth Banach spaces, and give its explicit solution. Two applications are presented—the first is to the Bounded Completion Problem involving approximation of Hardy class functions, while the second involves the construction of minimal vectors and hyperinvariant subspaces of linear operators, generalizing the Hilbert space technique of Ansari and Enflo.
The influence of deterministic noise on empirical measures generated by stationary processes
Authors: Davydov Youri , Zitikis Ričardas
Published: April 2004

We consider weak convergence of empirical measures generated by stationary random process

X
X

perturbed by deterministic noise

N
N

. We assume that the noise

N
N

has asymptotic distribution. In particular, we demonstrate that if the process

X
X

is ergodic, or satisfies some mixing assumptions, then the influence of deterministic noise

N
N

on

X
X

is the same as it would be if

N
N

were stochastic. Such results are of importance when investigating fluctuations and convex rearrangements of stochastic processes.
Continuous-trace groupoid crossed products
Authors: Fulman Igor , Muhly Paul , Williams Dana
Published: April 2004

Let

G
G

be a second countable, locally compact groupoid with Haar system, and let

A

\mathcal {A}

be a bundle of

C

∗

C^{\ast }

-algebras defined over the unit space of

G
G

on which

G
G

acts continuously. We determine conditions under which the associated crossed product

C

∗

(
G
;

A

)

C^{\ast }(G;\mathcal {A})

is a continuous trace

C

∗

C^{\ast }

-algebra.
Parametric decomposition of powers of ideals versus regularity of sequences
Authors: Goto Shiro , Shimoda Yasuhiro
Published: April 2004

Let

Q
=
(

a

1

,

a

2

,
⋯
,

a

s

)
 
(
⊊
A
)

Q = (a_{1}, a_{2}, \cdots , a_{s}) \ (\subsetneq A)

be an ideal in a Noetherian local ring

A
A

. Then the sequence

a

1

,

a

2

,
⋯
,

a

s

a_{1}, a_{2}, \cdots , a_{s}

is

A
A

-regular if every

a

i

a_{i}

is a non-zerodivisor in

A
A

and if
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper Q Superscript n Baseline equals intersection Underscript alpha Endscripts left-parenthesis a 1 Superscript alpha 1 Baseline comma a 2 Superscript alpha 2 Baseline comma midline-horizontal-ellipsis comma a Subscript s Superscript alpha Super Subscript s Superscript Baseline right-parenthesis">

Q

n

=

⋂

α

(

a

1

α

1

,

a

2

α

2

,
⋯
,

a

s

α

s

)

Q^{n} = \bigcap _{\alpha } (a_{1}^{\alpha _{1}}, a_{2}^{\alpha _{2}}, \cdots , a_{s}^{\alpha _{s}})

for all integers

n
≥
1

n \geq 1

, where

α
=
(

α

1

,

α

2

,
⋯
,

α

s

)

\alpha = (\alpha _{1}, \alpha _{2}, \cdots , \alpha _{s})

runs over the elements of the set
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Lamda Subscript s comma n Baseline equals left-brace left-parenthesis alpha 1 comma alpha 2 comma midline-horizontal-ellipsis comma alpha Subscript s Baseline right-parenthesis element-of double-struck upper Z Superscript s Baseline bar alpha Subscript i Baseline greater-than-or-equal-to 1 for all 1 less-than-or-equal-to i less-than-or-equal-to s and sigma-summation Underscript i equals 1 Overscript s Endscripts alpha Subscript i Baseline equals s plus n minus 1 right-brace">

Λ

s
,
n

=
{
(

α

1

,

α

2

,
⋯
,

α

s

)
∈

Z

s

∣

α

i

≥
1
 
for all
 
1
≤
i
≤
s
 
and
 

∑

i
=
1

s

α

i

=
s
+
n
−
1
}

\Lambda _{s,n} = \{(\alpha _{1}, \alpha _{2}, \cdots , \alpha _{s}) \in {\mathbb {Z}}^{s} \mid \alpha _{i} \geq 1 \ \text {for all} \ 1 \leq i \leq s \ \text {and} \ \sum _{i=1}^{s}\alpha _{i} = s + n - 1\}

.
On embeddings into toric prevarieties
Authors: Hausen J. , Schröer S.
Published: April 2004

We give examples of complete normal surfaces that are not embeddable into simplicial toric prevarieties nor toric prevarieties of affine intersection.
Bundles with periodic maps and mod 𝑝 Chern polynomial
Authors: Jaworowski Jan
Published: April 2004

Suppose that

E
→
B

E\to B

is a vector bundle with a linear periodic map of period

p
p

; the map is assumed free on the outside of the

0
0

-section. A polynomial

c

E

(
y
)

c_{E}(y)

, called a mod

p
p

Chern polynomial of

E
E

, is defined. It is analogous to the Stiefel-Whitney polynomial defined by Dold for real vector bundles with the antipodal involution. The mod

p
p

Chern polynomial can be used to measure the size of the periodic coincidence set for fibre preserving maps of the unit sphere bundle of

E
E

into another vector bundle.
Some numerical invariants of local rings
Authors: Montaner Josep
Published: April 2004

LetRRbe a formal power series ring over a field of characteristic zero andI⊆RI\subseteq Rany ideal. The aim of this work is to introduce some numerical invariants of the local ringsR/IR/Iby using the theory of algebraicD\mathcal {D}-modules. More precisely, we will prove that the multiplicities of the characteristic cycle of the local cohomology modulesHIn−i(R)H_I^{n-i}(R)andHpp(HIn−i(R))H_{\mathfrak {p}}^p(H_I^{n-i}(R)), wherep⊆R\mathfrak {p} \subseteq Ris any prime ideal that containsII, are invariants ofR/IR/I.
A simple proof that super-reflexive spaces are 𝐾-spaces
Authors: Sánchez Félix
Published: April 2004

We demonstrate the title.
A quasi-Hopf algebra freeness theorem
Authors: Schauenburg Peter
Published: April 2004

We prove the quasi-Hopf algebra version of the Nichols-Zoeller theorem: A finite dimensional quasi-Hopf algebra is free over any quasi-Hopf subalgebra.
Spectral radii and eigenvalues of subdivision operators
Authors: Chen Di-Rong
Published: April 2004

This paper discusses the spectra of matrix subdivision operators. We establish some formulas for spectral radii of subdivision operators on various invariant subspaces in

ℓ

p

\ell _{p}

. A formula for the spectral radius of a subdivision operator, in terms of the moduli of eigenvalues, is derived under a mild condition. The results are even new in the scalar case. In this case, we show that the subdivision operator has no eigenvector in

ℓ

p

\ell _{p}

if the corresponding subdivision scheme converges for some

p
∈
[
1
,
∞
)

p\in [1, \infty )

.
Common Borel directions of a meromorphic function with zero order and its derivative
Authors: Chern Tien-Yu
Published: April 2004

There is a meromorphic function of zero order for which the function and its derivative have no common Borel direction.
Unique continuation for second-order parabolic operators at the initial time
Authors: Albano Paolo , Tataru Daniel
Published: April 2004

We consider second-order parabolic equations with time independent coefficients. Under reasonable assumptions, it is known that the fundamental solution satisfies certain Gaussian bounds related to the associated geodesic distance. In this article we prove a sharp unique continuation property at the initial time which matches exactly the above-mentioned kernel bounds.
On a relaxation approximation of the incompressible Navier-Stokes equations
Authors: Brenier Yann , Natalini Roberto , Puel Marjolaine
Published: April 2004

We consider a hyperbolic singular perturbation of the incompressible Navier Stokes equations in two space dimensions. The approximating system under consideration arises as a diffusive rescaled version of a standard relaxation approximation for the incompressible Euler equations. The aim of this work is to give a rigorous justification of its asymptotic limit toward the Navier Stokes equations using the modulated energy method.
Convergence of sequences of pairwise independent random variables
Authors: Etemadi N. , Lenzhen A.
Published: April 2004

In spite of the fact that the tail

σ
\sigma

-algebra of a sequence of pairwise independent random variables may not be trivial, we have discovered that if such a sequence converges in probability or almost everywhere, then the limit has to be a constant. This enables us to provide necessary and sufficient conditions for its convergence, in terms of its marginal distribution functions.
Commutators of linear and bilinear Hilbert transforms
Authors: Blasco Oscar , Villarroya Paco
Published: April 2004

Let

α
∈

R

\alpha \in \mathbb {R}

, and let
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper H Subscript alpha Baseline left-parenthesis f comma g right-parenthesis left-parenthesis x right-parenthesis equals StartFraction 1 Over pi EndFraction p period v period integral f left-parenthesis x minus t right-parenthesis g left-parenthesis x minus alpha t right-parenthesis StartFraction d t Over t EndFraction">

H
α

(
f
,
g
)
(
x
)
=

1
π

p
.
v
.
∫
f
(
x
−
t
)
g
(
x
−
α
t
)

d
t

t

H_\alpha (f,g)(x)=\frac {1}{\pi } p.v. \int f(x-t)g(x-\alpha t)\frac {dt}{t}

and

H
f
(
x
)
=

1
π

p
.
v
.
∫
f
(
x
−
t
)

d
t

t

Hf(x)= \frac {1}{\pi } p.v.\int f(x-t)\frac {dt}{t}

denote the bilinear and linear Hilbert transforms, respectively. It is proved that, for

1
>
p
>
∞

1>p>\infty

and

α
1

≠

α
2

\alpha _1\ne \alpha _2

,

H

α
1

−

H

α
2

H_{\alpha _1}-H_{\alpha _2}

maps

L
p

×
B
M
O

L^p\times BMO

into

L

p

L^{p}

and it maps

B
M
O
×

L
p

BMO \times L^p

into

L

p

L^{p}

if and only if

sign
⁡
(

α
1

)
=
sign
⁡
(

α
2

)

\operatorname {sign}(\alpha _1)=\operatorname {sign}(\alpha _2)

. It is also shown that, for

α
≤
1

\alpha \le 1

the commutator

[

H

α
,
f

,
H
]

[H_{\alpha ,f},H]

is bounded on

L
p

L^p

for

1
>
p
>
∞

1>p>\infty

if and only if

f
∈
B
M
O

f\in BMO

, where

H

α
,
f

(
g
)
=

H
α

(
f
,
g
)

H_{\alpha ,f}(g)=H_\alpha (f,g)

.
Extension of positive definite functions from subgroups of nilpotent locally compact groups
Authors: Kaniuth Eberhard
Published: April 2004

We investigate the problem of when closed subgroups

H
H

of a nilpotent locally compact group

G
G

have the property that every continuous positive definite function on

H
H

extends to some such function on

G
G

.
Strong comparison principle for solutions of quasilinear equations
Authors: Lucia M. , Prashanth S.
Published: April 2004

Let

Ω
⊂

R

N

\Omega \subset \mathbb {R}^N

,

N
≥
1

N \geq 1

, be a bounded smooth connected open set and

a

:
Ω
×

R

N

→

R

N

\mathbf {a} : \Omega \times \mathbb {R}^N \to \mathbb {R}^N

be a map satisfying the hypotheses (H1)-(H4) below. Let

f
1

,

f
2

∈

L

l
o
c

1

(
Ω
)

f_1,f_2 \in \mathrm {L}_{loc}^{1} (\Omega )

with

f
2

≥

f
1

f_2 \geq f_1

,

f
1

≢

f
2

f_1 \not \equiv f_2

in

Ω
\Omega

and

u
1

,

u
2

∈

C

1
,
θ

(

Ω
¯

)

u_1, u_2 \in \mathcal {C}^{1,\theta } (\overline \Omega )

with

θ
∈
(
0
,
1
]

\theta \in (0,1]

be two weak solutions of
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-parenthesis upper P Subscript i Baseline right-parenthesis minus normal d normal i normal v left-parenthesis bold a left-parenthesis x comma nabla u Subscript i Baseline right-parenthesis right-parenthesis equals f Subscript i Baseline normal i normal n normal upper Omega comma i equals 1 comma 2 period">

(

P
i

)

−

d
i
v

(

a

(
x
,
∇

u
i

)
)
=

f
i

i
n

Ω
,

i
=
1
,
2.

(P_i)\quad -\mathrm {div} (\mathbf {a}(x,\nabla u_i)) = f_i \quad \mathrm {in }\,\Omega , \,\quad i=1,2.

\]
Suppose that

u
2

≥

u
1

u_2 \geq u_1

in

Ω
\Omega

. Then we show that

u
2

>

u
1

u_2 > u_1

in

Ω
\Omega

under the following assumptions: either

u
2

>

u
1

u_2>u_1

on

∂
Ω

\partial \Omega

, or

u
1

=

u
2

=
0

u_1=u_2=0

on

∂
Ω

\partial \Omega

and

u
1

≥
0

u_1 \geq 0

in

Ω
\Omega

. We also show a measure-theoretic version of the Strong Comparison Principle.
Subgroup separability of graphs of abelian groups
Authors: Metaftsis V. , Raptis E.
Published: April 2004

In the present paper we give necessary and sufficient conditions for the subgroup separability of the fundamental group of a finite graph of groups with finitely generated abelian vertex groups.
A bound for the dimension of the automorphism group of a homogeneous compact complex manifold
Authors: Snow Dennis
Published: April 2004

Let

X
X

be a homogeneous compact complex manifold, and let

Aut
⁡
(
X
)

\operatorname {Aut}(X)

be the complex Lie group of holomorphic automorphisms of 

X
X

. Examples show that

dim
⁡
Aut
⁡
(
X
)

\dim \operatorname {Aut} (X)

can grow exponentially in

n
=
dim
⁡
X

n = \dim X

. In this note it is shown that
\[

dim
⁡
Aut
⁡
(
X
)
≤

n
2

−
1
+

(

2
n
−
1

n
−
1

)

\dim \operatorname {Aut}(X) \le n^2-1+\binom {2n-1}{n-1}

\]
when

n
≥
3

n \ge 3

. Thus,

dim
⁡
Aut
⁡
(
X
)

\dim \operatorname {Aut} (X)

is at most exponential in 

n
n

. The proof relies on an upper bound for the dimension of the space of sections of the anticanonical bundle,

K
Y
∗

=
det

T
Y

K_Y^* = \det T_Y

, of a homogeneous projective rational manifold

Y
Y

of dimension 

m
m

:

dim
⁡

H
0

(
Y
,

K
Y
∗

)
≤

(

2
m
+
1

m

)

\dim H^0(Y,K_Y^*) \le \binom {2m+1}{m}

.
Local existence of 𝒦-sets, projective tensor products, and Arens regularity for 𝒜(ℰ₁+…+ℰ_{𝓃})
Authors: Graham Colin
Published: April 2004

Theorem. If

X

1

,
…
,

X

n

X_{1},\dots ,X_{n}

are perfect compact subsets of the locally compact metrizable abelian group, then there are pairwise disjoint perfect subsets

Y

1

⊆

X

1

,
…
,

Y

n

⊆

X

n

Y_{1}\subseteq X_{1},\dots ,Y_{n}\subseteq X_{n}

such that (i)

Y

j

Y_{j}

is either a Kronecker set or (ii) for some

p

j

≥
2

p_{j}\ge 2

,

Y

j

Y_{j}

is a translate of a

K

p

j

K_{p_{j}}

-set all of whose elements have order

p

j

p_{j}

, and (iii)

A
(

Y

1

+
⋯
+

Y

n

)

A(Y_{1}+\dots +Y_{n})

is isomorphic to the projective tensor product

C
(

Y

1

)

⊗
^

⋯

⊗
^

C
(

Y

n

)

C(Y_{1}) \hat \otimes \cdots \hat \otimes C(Y_{n})

. This extends what was previously known for groups such as

T

\mathbb {T}

or for the case

n
=
2

n=2

to the general locally compact abelian group. Old results concerning the local existence of Kronecker and

K

p

K_{p}

-sets are improved.
The ideal envelope of an operator algebra
Authors: Blecher David , Kaneda Masayoshi
Published: April 2004

A left ideal of any

C
∗

C^*

-algebra is an example of an operator algebra with a right contractive approximate identity (r.c.a.i.). Conversely, we show here that operator algebras with a r.c.a.i. should be studied in terms of a certain left ideal of a

C
∗

C^*

-algebra. We study operator algebras and their multiplier algebras from the perspective of “Hamana theory” and using the multiplier algebras introduced by the first author.
Finite Aomoto-Ito-Macdonald sums
Authors: de la Maza Ana-Cecilia
Published: April 2004

We present finite truncations of the Aomoto-Ito-Macdonald sums associated with root systems through a two-step reduction procedure. The first reduction restricts the sum from the root lattice to a Weyl chamber; the second reduction arises after imposing a truncation condition on the parameters, and gives rise to a finite sum over a Weyl alcove.
Generalized function algebras as sequence space algebras
Authors: Delcroix Antoine , Hasler Maximilian , Pilipovic Stevan , Valmorin Vincent
Published: April 2004

A topological description of various generalized function algebras over corresponding basic locally convex algebras is given. The framework consists of algebras of sequences with appropriate ultra(pseudo)metrics defined by sequences of exponential weights. Such an algebra with embedded Dirac’s delta distribution induces the discrete topology on the basic space.
Total curvatures of a closed curve in Euclidean 𝑛-space
Authors: Encinas L. , Muñoz Masqué J.
Published: April 2004

A classical result by J. W. Milnor states that the total curvature of a closed curve

C
C

in the Euclidean

n
n

-space is the limit of the total curvatures of polygons inscribed in

C
C

. In the present paper a similar geometric interpretation is given for all total curvatures

∫

C

|

κ

r

|

d

s

\int _{C}|\kappa _{r}|\mathrm {d}s

,

r
=
1
,
…
,
n
−
1

r=1,\ldots ,n-1

.
Notes on the largest irreducible character degree of a finite group
Authors: Guohua Qian
Published: April 2004

Let

G
G

be a finite group and

b
(
G
)

b(G)

the largest irreducible character degree of

G
G

. In this note, we show the following results: if

b
(
G
)
>

p
2

b(G)>p^2

, then

|

G
:

O
p

(
G
)

|

p

≤
p

|G:O_p(G)|_p\leq p

; if

b
(
G
)
>

p
m

b(G)>p^m

and, in addition,

G
G

is

p
p

-solvable with abelian Sylow

p
p

-subgroup, then

|

G
:

O
p

(
G
)

|

p

>

p
m

|G:O_p(G)|_p> p^m

.
Gorenstein derived functors
Authors: Holm Henrik
Published: April 2004

Over any associative ring

R
R

it is standard to derive

H
o
m

R

(
−
,
−
)

\mathrm {Hom}_R(-,-)

using projective resolutions in the first variable, or injective resolutions in the second variable, and doing this, one obtains

E
x
t

R
n

(
−
,
−
)

\mathrm {Ext}_R^n(-,-)

in both cases. We examine the situation where projective and injective modules are replaced by Gorenstein projective and Gorenstein injective ones, respectively. Furthermore, we derive the tensor product

−

⊗
R

−

-\otimes _R-

using Gorenstein flat modules.
Backward extensions of subnormal operators
Authors: Jung Il , Lambert Alan , Stochel Jan
Published: April 2004

The concept of backward extension for subnormal weighted shifts is generalized to arbitrary subnormal operators. Several differences and similarities in these contexts are explored, with emphasis on the structure of the underlying measures.
Faltings’ theorem for the annihilation of local cohomology modules over a Gorenstein ring
Authors: Khashyarmanesh K. , Salarian Sh.
Published: April 2004

In this paper we study the Annihilator Theorem and the Local-global Principle for the annihilation of local cohomology modules over a (not necessarily finite-dimensional) Noetherian Gorenstein ring.
𝐷-spaces and finite unions
Authors: Arhangel’skii Alexander
Published: April 2004

This article is a continuation of a recent paper by the author and R. Z. Buzyakova. New results are obtained in the direction of the next natural question: how complex can a space be that is the union of two (of a finite family) “nice" subspaces? Our approach is based on the notion of a

D
D

-space introduced by E. van Douwen and on a generalization of this notion, the notion of

a
D

aD

-space. It is proved that if a space

X
X

is the union of a finite family of subparacompact subspaces, then

X
X

is an

a
D

aD

-space. Under

(
C
H
)

(CH)

, it follows that if a separable normal

T
1

T_1

-space

X
X

is the union of a finite number of subparacompact subspaces, then

X
X

is Lindelöf. It is also established that if a regular space

X
X

is the union of a finite family of subspaces with a point-countable base, then

X
X

is a

D
D

-space. Finally, a certain structure theorem for unions of finite families of spaces with a point-countable base is established, and numerous corollaries are derived from it. Also, many new open problems are formulated.
Ternary cyclotomic polynomials with an optimally large set of coefficients
Authors: Bachman Gennady
Published: April 2004

Ternary cyclotomic polynomials are polynomials of the form

Φ

p
q
r

(
z
)
=

∏
ρ

(
z
−
ρ
)

\Phi _{pqr}(z)=\prod _\rho (z-\rho )

, where

p
>
q
>
r

p>q>r

are odd primes and the product is taken over all primitive

p
q
r

pqr

-th roots of unity

ρ
\rho

. We show that for every

p
p

there exists an infinite family of polynomials

Φ

p
q
r

\Phi _{pqr}

such that the set of coefficients of each of these polynomials coincides with the set of integers in the interval

[
−
(
p
−
1
)

/

2
,
(
p
+
1
)

/

2
]

[-(p-1)/2,(p+1)/2]

. It is known that no larger range is possible even if gaps in the range are permitted.
Periodic solutions of nonlinear impulsive differential inclusions with constraints
Authors: Cardinali Tiziana , Servadei Raffaella
Published: April 2004

In this paper we obtain the existence of periodic solutions for nonlinear “invariance” problems monitored by impulsive differential inclusions subject to impulse effects.