bluuebunny/crossref_metadata_2025 huggingface dataset:
How does individual smoking behaviour among hospital staff influence their knowledge of the health consequences of smoking?
Authors: Willaing Ingrid , Jørgensen Torben , Iversen Lars
Published: May 2004

Aims: This study examined associations between individual smoking habits among hospital staff and their knowledge of the health consequences of smoking and passive smoking. The a priori hypothesis was a higher level of knowledge among non-smokers compared with smokers. Methods: A survey was undertaken, based on self-administered questionnaires at a Danish hospital (Frederikssund Hospital) in the Copenhagen area. Descriptive statistics, chi-square test and multiple logistic regression analyses were used. A backward stepwise elimination of variables at a 5% level of significance was performed and 95% confidence intervals were calculated. Main outcome measures were knowledge of the health consequences of smoking, passive smoking and other lifestyle factors. Results: A total of 445 of 487 employees (91%) from all professional groups returned the questionnaire. Compared with ex- and never smokers, smokers systematically underestimate the health consequences of smoking and passive smoking independent of profession, department, sex, and age. There is no consistent association between knowledge of the health consequences of smoking and profession and department. There are significant inverse associations between smoking and knowledge of the health effects of excess use of alcohol and lack of physical activity. Conclusion: Individual smoking habits among hospital staff strongly influence smoking-related knowledge. No other variables are of consistent importance. These findings are supported by the literature. The validity of the study is good, but a similar study in a bigger population would strengthen the evidence.
A role for myosin-1A in the localization of a brush border disaccharidase
Authors: Tyska Matthew J. , Mooseker Mark S.
Published: May 2004

To gain insight regarding myosin-1A (M1A) function, we expressed a dominant negative fragment of this motor in the intestinal epithelial cell line, CACO-2BBE. Sucrase isomaltase (SI), a transmembrane disaccharidase found in microvillar lipid rafts, was missing from the brush border (BB) in cells expressing this fragment. Density gradient centrifugation, affinity purification, and immunopurification of detergent-resistant membranes isolated from CACO-2BBE cells and rat microvilli (MV) all indicate that M1A and SI reside on the same population of low density (∼1.12 g/ml) membranes. Chemical cross-linking of detergent-resistant membranes from rat MV indicates that SI and M1A may interact in a lipid raft complex. The functional significance of such a complex is highlighted by expression of the cytoplasmic domain of SI, which results in lower levels of M1A and a loss of SI from the BB. Together, these studies are the first to assign a specific role to M1A and suggest that this motor is involved in the retention of SI within the BB.
Asymptotically symmetric embeddings and symmetric quasicircles
Authors: Brania Abdelkrim , Yang Shanshuang
Published: May 2004

A well-known characterization of quasicircles is the following: A Jordan curve

J
J

in the complex plane is a quasicircle if and only if it is the image of the unit circle under a quasisymmetric embedding. In this paper we try to characterize a subclass of quasicircles, namely, symmetric quasicircles, by introducing the concept of asymptotically symmetric embeddings. We show that a Jordan curve

J
J

in the complex plane is a symmetric quasicircle if and only if it is the image of the unit circle under an asymptotically symmetric embedding.
Knot signature functions are independent
Authors: Cha Jae , Livingston Charles
Published: May 2004

A Seifert matrix is a square integral matrix

V
V

satisfying

det
(
V
−

V
T

)
=
±
1.

\begin{equation*}\det (V - V^T) =\pm 1. \end{equation*}

To such a matrix and unit complex number

ω
\omega

there corresponds a signature,
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="sigma Subscript omega Baseline left-parenthesis upper V right-parenthesis equals sign left-parenthesis left-parenthesis 1 minus omega right-parenthesis upper V plus left-parenthesis 1 minus omega overbar right-parenthesis upper V Superscript upper T Baseline right-parenthesis period">

σ
ω

(
V
)
=

sign

(
(
1
−
ω
)
V
+
(
1
−

ω
¯

)

V
T

)
.

\begin{equation*}\sigma _\omega (V) = \mbox {sign}( (1 - \omega )V + (1 - \bar {\omega })V^T). \end{equation*}

Let

S
S

denote the set of unit complex numbers with positive imaginary part. We show that

{

σ
ω

}

ω
∈
S

\{\sigma _\omega \}_ { \omega \in S }

is linearly independent, viewed as a set of functions on the set of all Seifert matrices. If

V
V

is metabolic, then

σ
ω

(
V
)
=
0

\sigma _\omega (V) = 0

unless

ω
\omega

is a root of the Alexander polynomial,

Δ
V

(
t
)
=
det
(
V
−
t

V
T

)

\Delta _V(t) = \det (V - tV^T)

. Let

A
A

denote the set of all unit roots of all Alexander polynomials with positive imaginary part. We show that

{

σ
ω

}

ω
∈
A

\{\sigma _\omega \}_ { \omega \in A }

is linearly independent when viewed as a set of functions on the set of all metabolic Seifert matrices. To each knot

K
⊂

S
3

K \subset S^3

one can associate a Seifert matrix

V
K

V_K

, and

σ
ω

(

V
K

)

\sigma _\omega (V_K)

induces a knot invariant. Topological applications of our results include a proof that the set of functions

{

σ
ω

}

ω
∈
S

\{\sigma _\omega \}_ { \omega \in S }

is linearly independent on the set of all knots and that the set of two–sided averaged signature functions,

{

σ
ω
∗

}

ω
∈
S

\{\sigma ^*_\omega \}_ { \omega \in S }

, forms a linearly independent set of homomorphisms on the knot concordance group. Also, if

ν
∈
S

\nu \in S

is the root of some Alexander polynomial, then there is a slice knot

K
K

whose signature function

σ
ω

(
K
)

\sigma _\omega (K)

is nontrivial only at

ω
=
ν

\omega = \nu

and

ω
=

ν
¯

\omega = \overline {\nu }

. We demonstrate that the results extend to the higher-dimensional setting.
Pure Picard-Vessiot extensions with generic properties
Authors: Juan Lourdes
Published: May 2004

Given a connected linear algebraic group

G
G

over an algebraically closed field

C
C

of characteristic 0, we construct a pure Picard-Vessiot extension for

G
G

, namely, a Picard-Vessiot extension

E

⊃

F

\mathcal E\supset \mathcal F

, with differential Galois group

G
G

, such that

E

\mathcal E

and

F

\mathcal F

are purely differentially transcendental over

C
C

. The differential field

E

\mathcal E

is the quotient field of a

G
G

-stable proper differential subring

R

\mathcal R

with the property that if

F
F

is any differential field with field of constants

C
C

and

E
⊃
F

E\supset F

is a Picard-Vessiot extension with differential Galois group a connected subgroup

H
H

of

G
G

, then there is a differential homomorphism

ϕ
:

R

→
E

\phi :\mathcal R\rightarrow E

such that

E
E

is generated over

F
F

as a differential field by

ϕ
(

R

)

\phi (\mathcal R)

.
The linear heat equation with highly oscillating potential
Authors: Kombe Ismail
Published: May 2004

In this paper we consider the following initial value problem:\[<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="StartLayout Enlarged left-brace 1st Row 1st Column StartFraction partial-differential u Over partial-differential t EndFraction equals minus upper H u plus upper V left-parenthesis x right-parenthesis u 2nd Column a m p semicolon in double-struck upper R Superscript upper N Baseline times left-parenthesis 0 comma upper T right-parenthesis comma 2nd Row 1st Column u left-parenthesis x comma 0 right-parenthesis equals u 0 left-parenthesis x right-parenthesis greater-than-or-equal-to 0 2nd Column a m p semicolon on double-struck upper R Superscript upper N Baseline times left-brace t equals 0 right-brace comma EndLayout">{∂u∂t=−Hu+V(x)uamp;in RN×(0,T),u(x,0)=u0(x)≥0amp;on RN×{t=0},\begin {cases} \frac {\partial u}{\partial t}=-Hu+V(x)u & \text {in $\mathbb {R}^N\times (0,T)$},\\ u(x,0) = u_0 (x)\geq 0 & \text {on $\mathbb {R}^N \times \{t=0\}$}, \end {cases}\]where<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper H equals negative normal upper Delta minus StartFraction beta Over StartAbsoluteValue x EndAbsoluteValue squared EndFraction sine left-parenthesis StartFraction 1 Over StartAbsoluteValue x EndAbsoluteValue Superscript alpha Baseline EndFraction right-parenthesis">H=−Δ−β|x|2sin⁡(1|x|α)H=-\Delta -\frac {\beta }{|x|^2}\sin (\frac {1}{|x|^{\alpha }})and0≤V∈Lloc1(RN)0\le V\in L_{\text {loc}}^1(\mathbb {R}^N). Nonexistence of positive solutions is analyzed.
A lower bound for the Bloch radius of 𝐾-quasiregular mappings
Authors: Rajala Kai
Published: May 2004

We give a quantitative proof to Eremenko’s theorem (2000), which extends Bloch’s classical theorem to the class of

n
n

-dimensional

K
K

-quasiregular mappings.
On simultaneous linear extensions of partial (pseudo)metrics
Authors: Tymchatyn E. , Zarichnyi M.
Published: May 2004

We consider the question of simultaneous extension of (pseudo) metrics defined on nonempty closed subsets of a compact metrizable space. The main result is a counterpart of the result due to Künzi and Shapiro for the case of extension operators of partial continuous functions and includes, as a special case, Banakh’s theorem on linear regular operators extending (pseudo)metrics.
Spectral gap for hyperbounded operators
Authors: Wang Feng-Yu
Published: May 2004

Let

(
E
,

F

,
μ
)

(E,\mathcal F,\mu )

be a probability space, and

P
P

a symmetric linear contraction operator on

L
2

(
μ
)

L^2(\mu )

with

P
1
=
1

P1=1

and

‖
P

‖

L
2

(
μ
)
→

L
4

(
μ
)

>
∞

\|P\|_{L^2(\mu )\to L^4(\mu )}>\infty

. We prove that

‖
P

‖

L
2

(
μ
)
→

L
4

(
μ
)

4

>
2

\|P\|_{L^2(\mu )\to L^4(\mu )}^4>2

is the optimal sufficient condition for

P
P

to have a spectral gap. Moreover, the optimal sufficient conditions are obtained, respectively, for the defective log-Sobolev and for the defective Poincaré inequality to imply the existence of a spectral gap. Finally, we construct a symmetric, hyperbounded, ergodic contraction

C
0

C_0

-semigroup without a spectral gap.
Infinite lifetime for the starlike dynamics in Hele-Shaw cells
Authors: Gustafsson Björn , Prokhorov Dmitri , Vasil’ev Alexander
Published: May 2004

One of the “folklore" questions in the theory of free boundary problems is the lifetime of the starlike dynamics in a Hele-Shaw cell. We prove precisely that, starting with a starlike analytic phase domain

Ω
0

\Omega _0

, the Hele-Shaw chain of subordinating domains

Ω
(
t
)

\Omega (t)

,

Ω
0

=
Ω
(
0
)

\Omega _0=\Omega (0)

, exists for an infinite time under injection at the point of starlikeness.
Birational morphisms of the plane
Authors: Shpilrain Vladimir , Yu Jie-Tai
Published: May 2004

Let

A
2

A^2

be the affine plane over a field

K
K

of characteristic

0
0

. Birational morphisms of

A
2

A^2

are mappings

A
2

→

A
2

A^2 \to A^2

given by polynomial mappings

φ
\varphi

of the polynomial algebra

K
[
x
,
y
]

K[x,y]

such that for the quotient fields, one has

K
(
φ
(
x
)
,
φ
(
y
)
)
=
K
(
x
,
y
)

K(\varphi (x), \varphi (y)) = K(x,y)

. Polynomial automorphisms are obvious examples of such mappings. Another obvious example is the mapping

τ
x

\tau _x

given by

x
→
x
,
 
y
→
x
y

x \to x, ~y \to xy

. For a while, it was an open question whether every birational morphism is a product of polynomial automorphisms and copies of

τ
x

\tau _x

. This question was answered in the negative by P. Russell (in an informal communication). In this paper, we give a simple combinatorial solution of the same problem. More importantly, our method yields an algorithm for deciding whether a given birational morphism can be factored that way.
Computing infima on convex sets, with applications in Hilbert spaces
Authors: Bridges Douglas , Ishihara Hajime , Vîţă Luminiţa
Published: May 2004

Using intuitionistic logic, we prove that under certain reasonable conditions, the infimum of a real-valued convex function on a convex set exists. This result is then applied to problems of simultaneous approximation in Hilbert space

H
H

and the corresponding operator space

B

(
H
)

.

\mathcal {B}\left (H\right ).

This enables us to establish that a bounded, weak-operator totally bounded, convex subset of

B

(
H
)

\mathcal {B}\left ( H\right )

is strong-operator located.
Essential domains and two conjectures in dimension theory
Authors: Fontana M. , Kabbaj S.
Published: May 2004

This note investigates two long-standing conjectures on the Krull dimension of integer-valued polynomial rings and of polynomial rings in the context of (locally) essential domains.
A singularity removal theorem for Yang-Mills fields in higher dimensions
Authors: Tao Terence , Tian Gang
Published: May 2004

In four and higher dimensions, we show that any stationary admissible Yang-Mills field can be gauge transformed to a smooth field if the

L
2

L^2

norm of the curvature is sufficiently small. There are three main ingredients. The first is Price’s monotonicity formula, which allows us to assert that the curvature is small not only in the

L
2

L^2

norm, but also in the Morrey norm

M
2

n

/

2

M_2^{n/2}

. The second ingredient is a new inductive (averaged radial) gauge construction and truncation argument which allows us to approximate a singular gauge as a weak limit of smooth gauges with curvature small in the Morrey norm. The second ingredient is a variant of Uhlenbeck’s lemma, allowing one to place a smooth connection into the Coulomb gauge whenever the Morrey norm of the curvature is small; This variant was also proved independently by Meyer and Rivière. It follows easily from this variant that a

W

1
,
2

W^{1,2}

-connection can be placed in the Coulomb gauge if it can be approximated by smooth connections whose curvatures have small Morrey norm.
A dynamically growing self-organizing tree (DGSOT) for hierarchical clustering gene expression profiles
Authors: Luo Feng , Khan Latifur , Bastani Farokh , Yen I-Ling , Zhou Jizhong
Published: May 2004

Motivation: The increasing use of microarray technologies is generating large amounts of data that must be processed in order to extract useful and rational fundamental patterns of gene expression. Hierarchical clustering technology is one method used to analyze gene expression data, but traditional hierarchical clustering algorithms suffer from several drawbacks (e.g. fixed topology structure; mis-clustered data which cannot be reevaluated). In this paper, we introduce a new hierarchical clustering algorithm that overcomes some of these drawbacks.

Result: We propose a new tree-structure self-organizing neural network, called dynamically growing self-organizing tree (DGSOT) algorithm for hierarchical clustering. The DGSOT constructs a hierarchy from top to bottom by division. At each hierarchical level, the DGSOT optimizes the number of clusters, from which the proper hierarchical structure of the underlying dataset can be found. In addition, we propose a new cluster validation criterion based on the geometric property of the Voronoi partition of the dataset in order to find the proper number of clusters at each hierarchical level. This criterion uses the Minimum Spanning Tree (MST) concept of graph theory and is computationally inexpensive for large datasets. A K-level up distribution (KLD) mechanism, which increases the scope of data distribution in the hierarchy construction, was used to improve the clustering accuracy. The KLD mechanism allows the data misclustered in the early stages to be reevaluated at a later stage and increases the accuracy of the final clustering result. The clustering result of the DGSOT is easily displayed as a dendrogram for visualization. Based on a yeast cell cycle microarray expression dataset, we found that our algorithm extracts gene expression patterns at different levels. Furthermore, the biological functionality enrichment in the clusters is considerably high and the hierarchical structure of the clusters is more reasonable.

Availability: DGSOT is available upon request from the authors.
TargetDB: a target registration database for structural genomics projects
Authors: Chen Li , Oughtred Rose , Berman Helen M. , Westbrook John
Published: May 2004

Summary: TargetDB is a centralized target registration database that includes protein target data from the NIH structural genomics centers and a number of international sites. TargetDB, which is hosted by the Protein Data Bank (RCSB PDB), provides status information on target sequences and tracks their progress through the various stages of protein production and structure determination. A simple search form permits queries based on contributing site, target ID, protein name, sequence, status and other data. The progress of individual targets or entire structural genomics projects may be tracked over time, and target data from all contributing centers may also be downloaded in the XML format.

Availability: TagetDB is available at http://targetdb.pdb.org/
Heterogeneity detector: finding heterogeneous positions in Phred/Phrap assemblies
Authors: Lee W. H. , Vega V. B.
Published: May 2004

Summary: A modification to Phred and program to detect heterogeneous positions, which is particularly useful in the identification of mutations and other abnormalities in Phred/Phrap genome assemblies.

Availability: The package is made available at http://giscompute.gis.a-star.edu.sg/~charlie/DHetero.html
SWAPSC: sliding window analysis procedure to detect selective constraints
Authors: Fares Mario A.
Published: May 2004

Summary: Sliding-window analysis procedure to detect selective constraints (SWAPSC) is a software system to dissect the constraints on the evolution of protein-coding genes. The program estimates rates of nucleotide substitutions at specific codon regions in each branch of a phylogenetic tree. The program uses several sets of simulated sequence alignments to estimate the probability of synonymous and non-synonymous nucleotide substitutions. Thereafter, a statistical analysis is conducted to determine the optimum window size to detect selective constraints. Finally, the optimum window size is slid along the real alignment and a test for significance of the estimated number of synonymous and non-synonymous nucleotide substitutions in each sliding step is conducted. A number of friendly useful output files is generated.

Availability: SWAPSC is available at http//www.may.ie/academic/biology/staff/mfmolecevolandbioinf.shtml. Distribution versions for both Linux and Windows operating systems are available, including manual and example files.
High Stakes in High Technology: High‐Tech Market Values as Options
Authors: Darby Michael R. , Liu Qiao , Zucker Lynne G.
Published: May 2004

In science‐based industries, world‐class scientists drive the most successful firms. These scientists are more likely to follow high‐stakes, high‐returns R&D strategies instead of more predictable incremental strategies. We develop an options pricing model in which the probability of stock‐price jumps increases with knowledge capital. GMM estimates show the probability of stock‐price jumps increases with three measures of knowledge capital intensity, two of which can be reasonably estimated contemporaneously. The model explains most variation in biotech firm market values. Firms with two standard deviations more knowledge capital are valued 10–50% more than firms with mean values of all variables.
The International Price Transmission in Stock Index Futures Markets
Authors: Yang Jian , Bessler David A.
Published: May 2004

This study explores dynamic price relationships among nine major stock index futures markets, combining an error‐correction model with directed acyclic graph (DAG) analysis. DAG‐based innovation accounting results show that the Japanese market is isolated from other major stock index futures markets. The United States and the United Kingdom appear to share leadership roles in stock index futures markets. The UK and German markets rather than the U.S. exert significant influences on most European markets, which indicates a pattern of regional integration in Europe. Innovation accounting results based on widely used Choleski decomposition are found to be seriously misleading.
Monetary Policy and the U.S. Stock Market
Authors: Hayford Marc D. , Malliaris A. G.
Published: May 2004

What is the influence of stock market valuations on monetary policy? We use a forward‐looking Taylor rule model to examine if monetary policy since the 19 October 1987 stock market crash has been influenced by the valuation of the stock market. We estimate the model using revised and real‐time data and find no empirical evidence that the Federal Reserve policy attempted to moderate stock market valuations during the late 1990s despite the “irrational exuberance” comments by Chairman Greenspan. Actually, the empirical evidence suggests that the Fed accommodated the high valuations of the stock market during this period.
Price Discrimination with Differentiated Products: Definition and Identification
Authors: Clerides Sofronis K.
Published: May 2004

There is no widely accepted definition of price discrimination with differentiated products. Either absolute price‐cost differences or percentage price‐cost markups are used as benchmarks for comparison. I show that the two criteria are qualitatively different: One may indicate price discrimination when the other does not. Moreover, anything other than marginal cost pricing will be identified as price discrimination by at least one of the two. I propose choosing a criterion based on the cost of arbitrage in the market under examination. Because this is often difficult to determine, it is advisable to always report results with both measures.
Durable‐Goods Monopoly with Privately Known Impatience: A Theoretical and Experimental Study
Authors: Güth Werner , Kröger Sabine , Normann Hans‐Theo
Published: May 2004

We analyze a durable‐goods monopoly selling a single unit of a good to a buyer whose value of the good is private information. The discount factors of the buyer and the seller may differ and are also privately known. We derive the closed‐form solution of a two‐period game and compare it to the behavior observed in experiments. The data are to a large extent consistent with the predictions.
Tax Uncertainty and Investment: A Cross‐Country Empirical Examination
Authors: Edmiston Kelly D.
Published: May 2004

An empirical examination of uncertain tax policy is crucial to a full understanding of the interplay between taxes and investment, especially given the ambiguities in the limited theoretical literature. This article empirically investigates the impact on investment of volatility in effective tax rates on capital income in a cross‐section of the 15 countries of the European Union, the United States, and Japan. Panel regression results suggest that the volatility of effective tax rates on capital income has a significant negative impact on investment per worker, with elasticities ranging from −0.012 to −0.029.
The Welfare Effects of the Reagan Deficits: A Portfolio Choice Approach
Authors: Ben‐Gad Michael
Published: May 2004

I analyze the incidence of U.S. fiscal policy using a two‐period, general equilibrium portfolio choice model with imperfect capital markets. Using data from the 1983–89 Panel Survey of Consumer Finances, I divide the population into three groups according to their 1982 portfolio choices and calculate average tax rates for each class of asset holders. Compared to the counterfactual of constant tax rates, the high deficits of the 1980 s harmed the welfare of two large minorities concentrated in both the higher‐ and lower‐income groups, but benefited the majority whose income fell largely in the middle of the income distribution.
Voter Preferences and State Regulation of Smoking
Authors: Hersch Joni , Rossi Alison F. Del , Viscusi W. Kip
Published: May 2004

Voters' preferences for smoking restrictions in restaurants, bars, malls, indoor sporting events, and hospitals are consistent with state‐level restrictions on smoking in each of these public areas. This analysis is based on constructed measures of political pressure that take into account both individual preferences and voting behavior. Although smokers are less likely to vote than nonsmokers, their lower voting rate does not substantially influence the probability that a state has a restriction. Other factors, such as tobacco's role in the state economy and state income, are rarely influential.
Testing the Determinants of Income Distribution in Major League Baseball
Authors: Jewell R. Todd , McPherson Michael A. , Molina David J.
Published: May 2004

Using data from U.S. Major League Baseball, this article compares parametric and nonparametric Gini coefficients for each team and year. We employ a panel‐data model to investigate the time‐series and cross‐sectional factors affecting the Gini coefficients and the parameters of the preselected distribution. We find that much of within‐team income distribution is determined by time‐related variables, with the 1994 MLB strike having an especially strong effect. A team's market potential does not seem to affect its salary distribution, but the average age of the players on a team's roster does. Furthermore, inequality first increases with team payroll, then decreases before increasing again.
The Importance of Gifts in Marriage
Authors: Parkman Allen M.
Published: May 2004

In this article, a new element is introduced into the household production function: gifts. Gifts occur when spouses use their time and/or incomes to produce commodities that usually only have value to their spouse, such as empathy and understanding. The difficulty of identifying a potential mate's capacity to produce gifts prior to marriage and of negotiating for them during marriage is argued as having contributed to the increase in the divorce rate. Evidence is provided that women are the spouses most likely to seek a divorce and part of their motivation is an inadequate receipt of gifts during marriage.
Subgame‐Perfect Punishment for Repeat Offenders
Authors: Emons Winand
Published: May 2004

First I show that for wealth‐constrained agents who may commit an act twice the optimal sanctions are the offender's entire wealth for the first and zero for the second crime. Then I ask the question whether this decreasing sanction scheme is subgame perfect (time consistent), that is, does a rent‐seeking government stick to this sanction scheme after the first crime has occurred. If the benefit and/or the harm from the crime are not too large, this is indeed the case; otherwise, equal sanctions for both crimes are optimal.
Willingness to Pay, Compensating Variation, and the Cost of Commitment
Authors: Zhao Jinhua , Kling Catherine L.
Published: May 2004

Hicksian welfare theory is static in nature, but many decisions are made in a dynamic environment. We present a dynamic model of an agent's decision to purchase or sell a good under the realistic conditions of uncertainty, irreversibility, and learning over time. Her willingness to pay (WTP) contains both the intrinsic value of the good as in Hicksian theory plus a commitment cost associated with delaying to obtain more information. The Hicksian equivalence between WTP/Willingness to accept (WTA) and compensating and equivalent variations no longer holds. The WTP and WTA divergence may arise and observed WTP values are not always appropriate for welfare analysis.
The Demand for Bank Reserves and Other Monetary Aggregates
Authors: Gillman Max , Kejak Michal
Published: May 2004

The article starts with Haslag's (1998) model of the bank's demand for reserves and reformulates it with a cash‐in‐advance approach for both financial intermediary and consumer. This gives a demand for a base of cash plus reserves that is not sensitive to who gets the inflation tax transfer. It extends the model to formulate a demand for demand deposits, yielding an M 1‐type demand, and then includes exchange credit, yielding an M 2‐type demand. Based on the comparative statics of the model, it provides an interpretation of the evidence on monetary aggregates. This explanation relies on the nominal interest as well as technology factors of the banking sector.
Shipping the Good Apples Out: A New Perspective
Authors: Bauman Yoram
Published: May 2004

An alternative explanation is provided for the Alchian and Allen substitution theorem, which posits that a per unit tax or shipping fee applied to similar goods will increase the relative consumption of the higher‐quality good. The usual explanation is that consumers substitute out of “bad apples” and into “good apples.” This article generalizes the Alchian and Allen result in an n‐good world, providing an alternative explanation that is more cogent in situations where the two goods (for example $500 and $5 wines) are not close substitutes.
Hypoxia induces macrophage inflammatory protein‐2 (MIP‐2) gene expression in murine macrophages via NF‐κB: the prominent role of p42/ p44 and PI3 kinase pathways
Authors: Zampetaki A. , Mitsialis S. A. , Pfeilschifter J. , Kourembanas S.
Published: May 2004

We have previously reported that hypoxia induces a pronounced inflammatory response in the mouse lung associated with elevated levels of specific chemokines. To further explore the mechanisms involved in lung inflammation, we exposed RAW 264.7 cells as well as mouse primary macrophages to hypoxia and analyzed chemokine gene expression. Among the genes examined, macrophage inflammatory protein‐2 (MIP‐2) expression was prominently induced by hypoxia both at the mRNA and the protein level. When RAW 264.7 cells were transfected with a panel of plasmids harboring a luciferase marker gene under the control of wild‐type or mutant variants of the MIP‐2 gene promoter, a strong hypoxic induction of expression (9‐ to 17‐fold) was observed. This induction was abolished by a mutation targeted to an NF‐κB binding site in the MIP‐2 promoter. Concordantly, specific NF‐κB binding to the cognate sequence was enriched in nuclear extracts from hypoxic but not normoxic RAW 264.7 cells. The mechanism of MIP‐2 gene induction by hypoxia was further characterized using inhibitors of signaling kinases. Inhibition of the p42/p44 and PI3 kinases but not p38 MAPK abolished the NF‐κB‐driven upregulation of MIP‐2 gene expression by hypoxia. This attenuation of the NF‐κB response to hypoxia did not involve decreased nuclear NF‐κB abundance but correlated with diminished transactivation potential of the p65 subunit. Our results indicate that the hypoxic signal for induction of MIP‐2 gene expression is implemented through enhanced NF‐κB activity and transmitted along the p42/44 and PI3 kinase pathways.
Estrogen and neuroprotection: higher constitutive expression of glutaredoxin in female mice offers protection against MPTP‐mediated neurodegeneration
Authors: Kenchappa Rajappa S. , Diwakar Latha , Annepu Jayasree , Ravindranath Vijayalakshmi
Published: May 2004

Incidence of Parkinson's disease is lower in women as compared with men. Although neuroprotective effect of estrogen is recognized, the underlying molecular mechanisms are unclear. MPTP (1‐methyl‐4‐phenyl‐1, 2, 3, 6, tetrahydro‐pyridine), a neurotoxin that causes Parkinson's disease‐like symptoms acts through inhibition of mitochondrial complex I. Administration of MPTP to male mice results in loss of dopaminergic neurons in substantia nigra, whereas female mice are unaffected. Oxidation of critical thiol groups by MPTP disrupts mitochondrial complex I, and up‐regulation of glutaredoxin (a thiol disulfide oxidoreductase) is essential for recovery of complex I. Early events following MPTP exposure, such as increased AP1 transcription, loss of glutathione, and up‐regulation of glutaredoxin mRNA is seen only in male mice, indicating that early response to neurotoxic insult does not occur in females. Pretreatment of female mice with ICI 182,780, estrogen receptor (ER) antagonist sensitizes them to MPTP‐mediated complex I dysfunction. Constitutive expression of glutaredoxin is significantly higher in female mice as compared with males. ICI 182,780 down‐regulates glutaredoxin activity in female mouse brain regions (midbrain and striatum), indicating that glutaredoxin expression is regulated through estrogen receptor signaling. Higher constitutive expression of glutaredoxin could potentially contribute to the neuroprotection seen in female mouse following exposure to neurotoxins, such as MPTP.
Hepatitis B viral HBx induces matrix metalloproteinase‐9 gene expression through activation of ERKs and PI‐3K/AKT pathways: Involvement of invasive potential
Authors: Chung Tae‐Wook , Lee Young‐Choon , Kim Cheorl‐Ho
Published: May 2004

Hepatitis B virus (HBV) X protein (HBx) has been shown to be essential for the development of hepatocellular carcinoma (HCC). Recently, we have found that HBx causes the progression of liver cancer through down‐expression of PTEN, known as a tumor suppressor gene (1). The prognosis for HCC depends mainly on the clinicopathological characteristic regarding invasion and metastasis. The expression of matrix metalloproteinase (MMP)‐9 has been implicated as playing an important role in HCC invasion and metastasis. We previously reported that HBV infection increased the invasiveness of hepatocytes and HCC cells through the transcriptional activation of MMP‐9 (2). The HBx was shown to activate the mitogen‐activated protein (MAP) kinase and phosphatidylinositol 3‐kinase (PI‐3K) signal cascade, which is essential for activation of transcription factors such as activating protein (AP)‐1 and nuclear factor (NF)‐κB. In this study, we show that the HBx protein stimulates the activities of the PI‐3K‐Akt/ protein kinase B (PKB) as well as extracellular signal‐regulated kinase 1/2 (ERK 1/2) in HBx‐transfected cells. Furthermore, we have shown that enhanced expression of MMP‐9 in HBx‐transfected cells mediated by not only activation of AP‐1 transcriptional activity through ERKs pathway but also activation of NF‐κB transcriptional activity through PI‐3K‐AKT/PKB pathway, and was associated with the invasive potential. However, treatment with U0126 (known as the ERKs inhibitor) or wortmannin (known as the PI‐3K inhibitor), but not SB203580 (known as the p38 MAPK inhibitor), markedly inhibited the expression of MMP‐9 induced by HBx in HBx‐ transfected cells. Seemingly, the invasiveness of HBx‐transfected cells was decreased by treating with U0126 or wortmannin, but not SB203580. These results clearly suggest that the HBx contributed to the transcriptional regulation of MMP‐9 through the ERKs and PI‐3K‐AKT/PKB pathway, and increased an invasive potential of cells.
Nitric oxide levels regulate macrophage commitment to apoptosis or necrosis during pneumococcal infection
Authors: Marriott Helen M. , Ali Farzana , Read Robert C. , Mitchell Tim J. , Whyte Moira K. B. , Dockrell David H.
Published: May 2004

Macrophages are resistant to constitutive apoptosis, but infectious stimuli can induce either microbial or host‐mediated macrophage apoptosis. Phagocytosis and killing of opsonized pneumococci by macrophages are potent stimuli for host‐mediated apoptosis, but the link between pneumococcal killing and apoptosis induction remains undefined. We now show phagocytosis of pneumococci by differentiated human monocyte‐derived macrophages (MDM) results in up‐regulation of inducible nitric oxide synthase (iNOS) and increased production of NO and reactive nitrogen species. NO accumulation in macrophages initiates an apoptotic program that involves NO‐dependent mitochondrial membrane permeabilization, Mcl‐1 down‐ regulation, and caspase activation and results in nuclear condensation and fragmentation. An inhibitor of mitochondrial permeability transition, bongkrekic acid, decreases pneumococcal‐ associated macrophage apoptosis. Conversely, inhibition of NO production using iNOS inhibitors decreases bacterial killing and shifts the cell death program from apoptosis to necrosis. Pneumolysin contributes to both NO production and apoptosis induction. After initial microbial killing, NO accumulation switches the macrophage phenotype from an activated cell to a cell susceptible to apoptosis. These results illustrate important roles for NO in the integration of host defense and regulation of inflammation in human macrophages.
Interactions between Sox9 and β-catenin control chondrocyte differentiation
Authors: Akiyama Haruhiko , Lyons Jon P. , Mori-Akiyama Yuko , Yang Xiaohong , Zhang Ren , Zhang Zhaoping , Deng Jian Min , Taketo Makoto M. , Nakamura Takashi , Behringer Richard R. , McCrea Pierre D. , de Crombrugghe Benoit
Published: May 2004

Chondrogenesis is a multistep process that is essential for endochondral bone formation. Previous results have indicated a role for β-catenin and Wnt signaling in this pathway. Here we show the existence of physical and functional interactions between β-catenin and Sox9, a transcription factor that is required in successive steps of chondrogenesis. In vivo, either overexpression of Sox9 or inactivation of β-catenin in chondrocytes of mouse embryos produces a similar phenotype of dwarfism with decreased chondrocyte proliferation, delayed hypertrophic chondrocyte differentiation, and endochondral bone formation. Furthermore, either inactivation of Sox9 or stabilization of β-catenin in chondrocytes also produces a similar phenotype of severe chondrodysplasia. Sox9 markedly inhibits activation of β-catenin-dependent promoters and stimulates degradation of β-catenin by the ubiquitination/proteasome pathway. Likewise, Sox9 inhibits β-catenin-mediated secondary axis induction in Xenopus embryos. β-Catenin physically interacts through its Armadillo repeats with the C-terminal transactivation domain of Sox9. We hypothesize that the inhibitory activity of Sox9 is caused by its ability to compete with Tcf/Lef for binding to β-catenin, followed by degradation of β-catenin. Our results strongly suggest that chondrogenesis is controlled by interactions between Sox9 and the Wnt/β-catenin signaling pathway.
Angiopoietin-1 modulates endothelial cell function and gene expression via the transcription factor FKHR (FOXO1)
Authors: Daly Christopher , Wong Vivian , Burova Elena , Wei Yi , Zabski Stephanie , Griffiths Jennifer , Lai Ka-Man , Lin Hsin Chieh , Ioffe Ella , Yancopoulos George D. , Rudge John S.
Published: May 2004

Despite genetic evidence establishing angiopoietin-1 (Ang-1) as an essential regulator of vascular development, the molecular mechanisms underlying Ang-1 function are almost completely uncharacterized. In this report, we demonstrate that Ang-1, via Akt activation, is a potent inhibitor of the forkhead transcription factor FKHR (FOXO1), identifying for the first time a nuclear signaling pathway through which Ang-1 modulates gene expression. We use microarray analysis to show that FKHR, whose function in endothelial cells has not previously been elucidated, regulates many genes associated with vascular destabilization and remodeling (including angiopoietin-2, an Ang-1 antagonist) and endothelial cell apoptosis (e.g., survivin, TRAIL). Ang-1 inhibits FKHR-mediated changes in gene expression and FKHR-induced apoptosis. Analysis of gene expression changes induced by an activated version of Akt confirms that FKHR is a major target through which Akt regulates transcription in endothelial cells. We use RNA interference to demonstrate that FKHR is required for the expression of genes (including Ang-2) that have important vascular functions. Our data suggest a novel, tissue-specific role for the Akt/FKHR pathway in the vasculature and suggest a mechanistic basis for the previously described actions of Ang-1 as a regulator of endothelial cell survival and blood vessel stability.
Positive and negative functions of the SAGA complex mediated through interaction of Spt8 with TBP and the N-terminal domain of TFIIA
Authors: Warfield Linda , Ranish Jeffrey A. , Hahn Steven
Published: May 2004

A surface that is required for rapid formation of preinitiation complexes (PICs) was identified on the N-terminal domain (NTD) of the RNA Pol II general transcription factor TFIIA. Site-specific photocross-linkers and tethered protein cleavage reagents positioned on the NTD of TFIIA and assembled in PICs identified the SAGA subunit Spt8 and the TFIID subunit Taf4 as located near this surface. In agreement with these findings, mutations in Spt8 and the TFIIA NTD interact genetically. Using purified proteins, it was found that TFIIA and Spt8 do not stably bind to each other, but rather both compete for binding to TBP. Consistent with this competition, Spt8 inhibits the binding of SAGA to PICs in the absence of activator. In the presence of activator, Spt8 enhances transcription in vitro, and the positive function of the TFIIA NTD is largely mediated through Spt8. Our results suggest a mechanism for the previously observed positive and negative effects of Spt8 on transcription observed in vivo.
Recruitment of NIMA kinase shows that maturation of theS. pombespindle-pole body occurs over consecutive cell cycles and reveals a role for NIMA in modulating SIN activity
Authors: Grallert Agnes , Krapp Andrea , Bagley Steve , Simanis Viesturs , Hagan Iain M.
Published: May 2004

Mitotic exit inSaccharomyces cerevisiaeand septation inSchizosaccharomyces pombeare regulated by a conserved signaling network called the mitotic exit and septum initiation networks (SIN), respectively. The network is active on one of the two anaphase B spindle-pole bodies (SPBs). Whereas the inherent asymmetry of growth by budding accounts for elements of the asymmetry inS. cerevisiae, it has been unclear how, or why, the pathway is asymmetric inS. pombe. We show that elements of SPB duplication inS. pombeare conservative, and that the SIN is active on the new SPB. SIN association with the new SPB persists after transient depolymerization of microtubules. The localization of the NIMA-related kinase, Fin1, reveals further complexity in SPB inheritance. Fin1 associates with the SPB bearing the older components in all cells and with the “new” SPB in half of the population. Fin1 only binds the new SPB when this new SPB has arisen from the duplication of an SPB that is two or more cycles old. Thus, each of the four SPBs generated over two consecutive cell cycles are different, because they have distinct fates in the next cell cycle. Fin1 binds the SPB once the SIN is active and the association requires the SIN inhibitors Byr4 and Cdc16. Fin1 physically associates with Byr4. Compromising Fin1 function leads to SIN activation on both anaphase B SPBs and promotes septation, indicating that Fin1 restrains SIN activity on the old SPB.
Pol12, the B subunit of DNA polymerase α, functions in both telomere capping and length regulation
Authors: Grossi Simona , Puglisi Andrea , Dmitriev Petr V. , Lopes Massimo , Shore David
Published: May 2004

The regulation of telomerase action, and its coordination with conventional DNA replication and chromosome end “capping,” are still poorly understood. Here we describe a genetic screen in yeast for mutants with relaxed telomere length regulation, and the identification of Pol12, the B subunit of the DNA polymerase α (Pol1)-primase complex, as a new factor involved in this process. Unlike many POL1 and POL12 mutations, which also cause telomere elongation, the pol12-216 mutation described here does not lead to either reduced Pol1 function, increased telomeric single-stranded DNA, or a reduction in telomeric gene silencing. Instead, and again unlike mutations affecting POL1, pol12-216 is lethal in combination with a mutation in the telomere end-binding and capping protein Stn1. Significantly, Pol12 and Stn1 interact in both two-hybrid and biochemical assays, and their synthetic-lethal interaction appears to be caused, at least in part, by a loss of telomere capping. These data reveal a novel function for Pol12 and a new connection between DNA polymerase α and Stn1. We propose that Pol12, together with Stn1, plays a key role in linking telomerase action with the completion of lagging strand synthesis, and in a regulatory step required for telomere capping.
Divergent functions of murine Pax3 and Pax7 in limb muscle development
Authors: Relaix Frédéric , Rocancourt Didier , Mansouri Ahmed , Buckingham Margaret
Published: May 2004

Pax genes encode evolutionarily conserved transcription factors that play critical roles in development. Pax3 and Pax7 constitute one of the four Pax subfamilies. Despite partially overlapping expression domains, mouse mutations for Pax3 and Pax7 have very different consequences. To investigate the mechanism of these contrasting phenotypes, we replaced Pax3 by Pax7 by using gene targeting in the mouse. Pax7 can substitute for Pax3 function in dorsal neural tube, neural crest cell, and somite development, but not in the formation of muscles involving long-range migration of muscle progenitor cells. In limbs in which Pax3 is replaced by Pax7, the severity of the muscle phenotype increases as the number of Pax7 replacement alleles is reduced, with the forelimb more affected than the hindlimb. We show that this hypomorphic activity of Pax7 is due to defects in delamination, migration, and proliferation of muscle precursor cells with inefficient activation of c-met in the hypaxial domain of the somite. Despite this, overall muscle patterning is retained. We conclude that functions already prefigured by the single Pax3/7 gene present before vertebrate radiation are fulfilled by Pax7 as well as Pax3, whereas the role of Pax3 in appendicular muscle formation has diverged, reflecting the more recent origin of this mode of myogenesis.
The new conception of the laboratory testing of the FBW control system for small aircraft
Authors: Dolega Boguslaw , Rogalski Tomasz
Published: May 2004

The paper presents conception and practical realization of laboratory testing of control system for small aircraft. The stand used in these tests is prepared in Matlab and Simulink environment. Usage of xPC and RTW modules enables the system to perform “Hardware in the loop” real time tests including tests with pilots. As a hardware PC computer equipped with specialized boards, including A/C, C/A, converters and RS232, LPT, CAN 2B data lines was used. The main task of presented stand is to make possible tests of control system introducing new conception of aircraft controlling (e.g. smart control and decoupled control techniques).
A potentiodynamic and SEM study of the behaviour of iron in pH 8.9‐11.0 phosphate solutions
Authors: Giacomelli Cristiano , Spinelli Almir
Published: May 2004

The behaviour of iron electrodes immersed in pH 8.9‐11.0 Na2HPO4 solutions was studied by potentiodynamic measurements (cyclic voltammetry) and scanning electron microscopy (SEM). The influence of proton and phosphate content, scan rate, anodic switching potential and other devised potential/time perturbation regimes were evaluated in order to obtain an understanding of the reactions involved during the passivation process. The oxidation‐reduction peaks were analysed using a thermodynamic approach. It was possible to reveal the most important reactions coming about on the electrode surface, which comprise, initially, the formation of Fe3(PO4)2 and Fe(OH)2 at ca. −0.8 V/SCE. Subsequently, these ferrous species are further oxidized to γ‐FeOOH at ca. −0.36 V/SCE, the latter being transformed into Fe2O3 in the passive region. Depending on the pH value (11.0) and scan rate (slow), Fe3O4 is clearly present as an intermediate oxide structure between the ferrous and ferric species mentioned earlier. In addition, scan rate was discovered to play a remarkable influence on the surface morphology observed during the SEM examinations.
Assessing the Effectiveness of Open Learning
Authors: Rowe Christopher
Published: May 2004

British Aerospace (MAD) has launched Open Learning Centres on three of
its sites with a fourth to open shortly. Considers the various
mechanisms being used to assess overall effectiveness and identifies
three strands of the process: measurement, monitoring and evaluation.
Concludes with the contention that tensions can exist, when launching an
Open Learning Centre, between creating the learning organization and
meeting the business need.