bluuebunny/crossref_metadata_2025 huggingface dataset:
The relation between soil structure and solute transport under raised bed cropping and conventional cultivation in south-western Victoria
Authors: Holland J. E. , White R. E. , Edis R.
Published: December 2007

This study examined the relationship between soil structure and solute transport in a texture contrast soil under 2 different tillage treatments—raised beds and conventional cultivation—in south-western Victoria. Undisturbed soil samples were collected for resin-impregnation and image analysis. This enabled several descriptive parameters of macropore structure to be calculated. Large, undisturbed soil samples were also collected for a solute transport experiment using a KCl solution. A convective log-normal transfer function was used to model Cl– movement. The assessment of soil structure showed that the raised beds contained a better connected pore network than the conventionally cultivated soil. Solute transport was faster through the raised bed soil when close to saturation (at –5 mm tension). Under these conditions, the solute transport parameters showed a smaller ratio of transport volume to soil water volume in the raised bed than the conventionally cultivated soil. Together, these data strongly indicate that the raised beds had greater pore connectivity and were able to transmit solute faster and more efficiently than the conventionally cultivated soil. It is concluded that raised bed soils are better structured and provide less risk from waterlogging than conventionally cultivated soils. However, there is greater potential for preferential flow of pesticides and solutes in raised bed soils.
Nitrogen contributions in a windmill grass (Chloris truncata) - wheat (Triticum aestivum L.) system in south-western Australia
Authors: Syme H. , Acuña T. L. Botwright , Abrecht D. , Wade L. J.
Published: December 2007

Chloris truncata, a perennial grass that is native to Australia, has potential as a short-lived summer pasture in rotation with wheat and other winter crops in the low to medium rainfall zone of south-western Australia. In this paper we examine the nitrogen contributions from a C. truncata–wheat system, with the expectation that C. truncata may take up nitrate which would otherwise be lost to leaching, for later release to the following wheat crop. In glasshouse experiments, residual soil nitrate in bare soil was available for uptake and growth of wheat, with a greater response when N was applied. In contrast, wheat grown on C. truncata stubble was mostly reliant on recently mineralised nitrogen, as the previous rotation had depleted the soil of nitrate. Shoot stubble of C. truncata provided sufficient mineralised nitrogen such that the uptake of nitrogen and biomass of wheat equalled those from bare soil. Wheat grown on root stubble of C. truncata had half the biomass production of that grown on either bare soil or shoot stubble, with root + shoot stubble intermediate. In a field trial undertaken at Bruce Rock in Western Australia, nitrogen release from C. truncata stubble at low to intermediate stubble densities increased tiller production, nitrogen uptake, and growth of wheat, but not at the highest N rate in this season, which received below-average rainfall in July. These results provide initial evidence concerning how a C. truncata–wheat system could improve the N balance of the farming system, by potentially reducing the leaching loss of nitrate in autumn, and then releasing mineralised N from stubble when needed by a following wheat crop. While these results require further confirmation, especially in the field, they raise exciting prospects for an improved agronomic system, with potential benefits to N balance, carrying capacity, yield stability, and groundwater discharge. The system requires further study to quantify these processes, and explore their implications.
ERK MAP kinase is targeted to RSK2 by the phosphoprotein PEA-15
Authors: Vaidyanathan Hema , Opoku-Ansah John , Pastorino Sandra , Renganathan Hema , Matter Michelle L. , Ramos Joe W.
Published: December 2007

The ERK pathway responds to extracellular stimuli and oncogenes by modulating cellular processes, including transcription, adhesion, survival, and proliferation. ERK has diverse substrates that carry out these functions. The processes that are modulated are determined in part by the substrates that ERK phosphorylates. We demonstrate that PEA-15 (phosphoprotein enriched in astrocytes, 15 kDa) targets ERK to RSK2 and thereby enhances RSK2 activation. PEA-15 independently bound ERK and RSK2 and increased ERK association with RSK2 in a concentration-dependent manner. PEA-15 increased RSK2 activity and CREB-mediated transcription, and this process was regulated by phosphorylation of PEA-15. Finally, phorbol ester stimulation of PEA-15-null lymphocytes resulted in impaired RSK2 activation that was rescued by exogenous PEA-15 expression. Therefore, PEA-15 functions as a scaffold to enhance ERK activation of RSK2, and this activity is regulated by phosphorylation. Thus, PEA-15 can integrate signal transduction to provide a specific physiological outcome from activation of the multipotent ERK MAP kinase pathway.
Sonic Hedgehog promotes the development of multipotent neural crest progenitors endowed with both mesenchymal and neural potentials
Authors: Calloni Giordano W. , Glavieux-Pardanaud Corinne , Le Douarin Nicole M. , Dupin Elisabeth
Published: December 2007

In the vertebrate embryo, the cephalic neural crest cells (CNCCs) produce cells belonging to two main lineages: the neural [including neurons, glial cells of the peripheral nervous system (PNS), and melanocytes] and the mesenchymal (chondrocytes, osteoblasts, smooth muscle cells, and connective tissue cells), whereas the trunk NCCs (TNCCs) in amniotes yield only neural derivatives. Although multipotent cells have previously been evidenced by
in vitro
clonal analysis, the issue as to whether all of the mesenchymal and neural phenotypes can be derived from a unique NC stem cell has remained elusive. In the present work, we devised culture conditions that led us to identify a highly multipotent NCC endowed with both neural and mesenchymal potentials, which lies upstream of all the other NC progenitors known so far. We found that addition of recombinant Sonic Hedgehog (Shh) increased the number of CNCC progenitors yielding both mesenchymal and neural lineages and promoted the development of such precursors from the TNCC. Shh decreased the neural-restricted precursors without affecting the overall CNCC survival and proliferation. By showing a differential positive effect of Shh on the expression of mesenchymal phenotypes (i.e., chondrocytes and smooth muscle cells) by multipotent CNCCs, these results shed insights on the
in vivo
requirement of Shh for craniofacial morphogenesis. Together with evolutionary considerations, these data also suggest that the mesenchymal-neural precursor represents the ancestral form of the NC stem cell, which in extinct forms of vertebrates (the ostracoderms) was able to yield both the PNS and superficial skeleton.
THE NEW WELFARE STATE SETTLEMENT IN EUROPE
Authors: Taylor-Gooby Peter
Published: December 2007

The post-war settlement rested on confidence that state welfare combined with neo-Keynesian economic management supported economic progress and enhanced social stability. New approaches from the 1970s onwards inspired by monetarism saw extensive state welfare as a damaging economic burden. The welfare settlement that is currently emerging in European debates argues that a welfare state centred on social investment, combined with appropriate de-regulation and use of social benefits to support employment mobility can again contribute to economic and social objectives in a virtuous spiral of growth and justice. In practice, however, most European states have been far more successful in what might broadly be called negative activation (less regulation, restrictions on passive benefits and targeted help for high-risk groups), than in investment to enhance the knowledge base and improve mobility. The differences between the new social investment welfare state and more limited de-regulated welfare system seem to be less marked in practice than the tenor of policy debate implies.
Publishing technologies: what does the future hold?
Authors: PENNY Dan
Published: December 2007

Web technologies have given publishers and researchers alike opportunities to interact in new ways. These have had an impact on business models, the value of formal and informal communication, and the role of publishers in the networked community. This article looks at some recent examples which are likely to set precedents for the future of publishing technologies. In particular, it focuses on the evolution of Web searching, the growing importance of online communities, the potential of Web tools for self‐publishing, and the way in which publishers can control their content even post‐publication. It also suggests that the recent rash of e‐book readers is unlikely to be of importance to scholarly publishing.
Innovation and the Wiley—Blackwell Compass Journals
Authors: LAFAYE Vanessa
Published: December 2007

‘Innovation’ is one of those words, like ‘challenge', which inspires different reactions in different people. Depending on one's background or job sector, it can either represent an exciting opportunity or a resource‐draining waste of time. Yet innovate we must, to satisfy our markets' increasing expectations, especially in the online environment. Some brand leaders have separate ‘laboratories’ where new features and ideas are developed and floated for feedback. In the absence of such a dedicated space, there are several issues relating to innovation within a publishing organization. This article looks at how these are handled at Wiley–Blackwell in the Compass journals team, and tries to distil some working principles.
Data, disciplines, and scholarly publishing
Authors: BORGMAN Christine L.
Published: December 2007

Data are becoming an essential product of scholarship, complementing the roles of journal articles, papers, and books. Research data can be reused to ask new questions, to replicate studies, and to verify research findings. Data become even more valuable when linked to publications and other related resources to form a value chain. Types and uses of data vary widely between disciplines, as do the online availability of publications and the incentives of scholars to publish their data. Publishers, scholars, and librarians each have roles to play in constructing a new scholarly information infrastructure for e‐research. Technical, policy, and institutional components are maturing; the next steps are to integrate them into a coherent whole. Achieving a critical mass of datasets in public repositories, with links to and from publisher databases, is the most promising solution to maintaining and sustaining the scholarly record in digital form.
Book Review
Authors: WELHAM Robert
Published: December 2007

Peer Review: The Challenges for the Humanities and Social Sciences A British Academy Report British Academy, 2007, 61 pp. Freely available online at http://www.britac.ac.uk/reports/peer‐review/index.html; print copies available on request from Ms Vivienne Hurley, The British Academy, 10 Carlton House Terrace, London SW1P 5AH, UK; tel. +44 (0)20 7969 5268; email v.hurley@britac.ac.uk
Classifying Serre subcategories of finitely presented modules
Authors: Garkusha Grigory , Prest Mike
Published: December 2007

Given a commutative coherent ring

R
R

, a bijective correspondence between the thick subcategories of perfect complexes

D

per

(
R
)

\mathcal D_{\operatorname {per}}(R)

and the Serre subcategories of finitely presented modules is established. To construct this correspondence, properties of the Ziegler and Zariski topologies on the set of isomorphism classes of indecomposable injective modules are used in an essential way.
On a problem of Axler, Cuckovic and Rao
Authors: Cao Guangfu
Published: December 2007

In this note we show that if two Toeplitz operators on a Bergman space of the (Levi) pseudoconvex domain commute and the symbol of one of them is analytic and non-constant, then the other one is also analytic. This gives an affirmative answer of a problem of S. Axler, Z. Cuckovic and N. V. Rao (1999).
Topologically transitive skew-products of backward shift operators and hypercyclicity
Authors: Costakis George , Hadjiloucas Demetris
Published: December 2007

In this article we look at skew-products of multiples of the backward shift and examine conditions under which the skew-product is topologically transitive or hypercyclic in the second coordinate. We also give an application of the theory to iterated function systems of multiples of backward shift operators.
On fixed point theorems of Leray–Schauder type
Authors: Borkowski Marcin , Bugajewski Dariusz
Published: December 2007

In this paper we prove a few fixed points theorems of Leray–Schauder type in hyperconvex metric spaces.
Limit cycles for cubic systems with a symmetry of order 4 and without infinite critical points
Authors: Álvarez M. , Gasull A. , Prohens R.
Published: December 2007

In this paper we study those cubic systems which are invariant under a rotation of

2
π

/

4

2\pi /4

radians. They are written as

z
˙

=
ε
z
+
p

z
2

z
¯

−

z
¯

3

,

\dot {z}=\varepsilon z+p\,z^2\bar {z}-\bar {z}^3,

where

z
z

is complex, the time is real, and

ε
=

ε
1

+
i

ε
2

\varepsilon =\varepsilon _1+i\varepsilon _2

,

p
=

p
1

+
i

p
2

p=p_1+ip_2

are complex parameters. When they have some critical points at infinity, i.e.

|

p
2

|

≤
1

|p_2|\le 1

, it is well-known that they can have at most one (hyperbolic) limit cycle which surrounds the origin. On the other hand when they have no critical points at infinity, i.e.

|

p
2

|

>
1
,

|p_2|>1,

there are examples exhibiting at least two limit cycles surrounding nine critical points. In this paper we give two criteria for proving in some cases uniqueness and hyperbolicity of the limit cycle that surrounds the origin. Our results apply to systems having a limit cycle that surrounds either 1, 5 or 9 critical points, the origin being one of these points. The key point of our approach is the use of Abel equations.
Cantor singular continuous spectrum for operators along interval exchange transformations
Authors: Cobo M. , Gutierrez C. , de Oliveira C.
Published: December 2007

It is shown that Schrödinger operators, with potentials along the shift embedding of Lebesgue almost every interval exchange transformations, have Cantor spectrum of measure zero and pure singular continuous for Lebesgue almost all points of the interval.
A central extension theorem for essential dimensions
Authors: Kang Ming-Chang
Published: December 2007

LetKKbe an arbitrary field andGGa finite group. We will denote byedK⁡(G)\operatorname {ed}_K(G)the essential dimension ofGGoverKK. A generalization of the central extension theorem of Buhler and Reichstein (Compositio Math.106(1997) 159–179, Theorem 5.3) is obtained.
On sums of powers of inverse complete quotients
Authors: Jenkinson Oliver
Published: December 2007

For an irrational number

x
x

, let

x
n

x_n

denote its

n
n

-th continued fraction inverse complete quotient, obtained by deleting the first

n
n

partial quotients. For any positive real number

r
r

, we establish the optimal linear bound on the sum of the

r
r

-th powers of the first

n
n

complete quotients. That is, we find the smallest constants

α
(
r
)
,
β
(
r
)

\alpha (r), \beta (r)

such that

x
1
r

+
…
+

x
n
r

>
α
(
r
)
n
+
β
(
r
)

x_1^r+\ldots +x_n^r> \alpha (r)n+\beta (r)

for all

n
≥
1

n\ge 1

and all irrationals

x
x

.
Projective normality of ruled surfaces
Authors: Park Euisung
Published: December 2007

In this article we study normal generation of irrational ruled surfaces. When

C
C

is a smooth curve of genus

g
g

, Green and Lazarsfeld proved that a very ample line bundle

L
∈

Pic

X

L \in \mbox {Pic}X

with

deg

(
L
)
≥
2
g
+
1
−
2

h
1

(
X
,
L
)
−

Cliff

(
X
)

\mbox {deg}(L) \geq 2g+1-2h^1 (X,L) - \mbox {Cliff}(X)

is normally generated where

Cliff

(
C
)

\mbox {Cliff}(C)

denotes the Clifford index of the curve

C
C

(Green and Lazarsfeld, 1986). We generalize this to line bundles on a ruled surface over

C
C

.
Codes over rings of size four, Hermitian lattices, and corresponding theta functions
Authors: Shaska T. , Wijesiri G.
Published: December 2007

Let

K
=
Q
(

−
ℓ

)

K=Q(\sqrt {-\ell })

be an imaginary quadratic field with ring of integers

O

K

\mathcal {O}_K

, where

ℓ
\ell

is a square free integer such that

ℓ
≡
3

mod

4

\ell \equiv 3 \mod 4

, and let

C
=
[
n
,
k
]

C=[n, k]

is a linear code defined over

O

K

/

2

O

K

\mathcal {O}_K/2\mathcal {O}_K

. The level

ℓ
\ell

theta function

Θ

Λ

ℓ

(
C
)

\Theta _{\Lambda _{\ell } (C) }

of

C
C

is defined on the lattice
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Lamda Subscript script l Baseline left-parenthesis upper C right-parenthesis colon equals StartSet x element-of script upper O Subscript upper K Superscript n Baseline colon rho Subscript script l Baseline left-parenthesis x right-parenthesis element-of upper C EndSet">

Λ

ℓ

(
C
)
:=
{
x
∈

O

K
n

:

ρ
ℓ

(
x
)
∈
C
}

\Lambda _{\ell } (C):= \{ x \in \mathcal {O}_K^n : \rho _\ell (x) \in C\}

, where

ρ

ℓ

:

O

K

→

O

K

/

2

O

K

\rho _{\ell }:\mathcal {O}_K \rightarrow \mathcal {O}_K/2\mathcal {O}_K

is the natural projection. In this paper, we prove that: i) for any

ℓ
,

ℓ
′

\ell , \ell ^\prime

such that

ℓ
≤

ℓ
′

\ell \leq \ell ^\prime

,

Θ

Λ
ℓ

(
q
)

\Theta _{\Lambda _\ell }(q)

and

Θ

Λ

ℓ
′

(
q
)

\Theta _{\Lambda _{\ell ^\prime }}(q)

have the same coefficients up to

q

ℓ
+
1

4

q^{\frac {\ell +1}{4}}

, ii) for

ℓ
≥

2
(
n
+
1
)
(
n
+
2
)

n

−
1

\ell \geq \frac {2(n+1)(n+2)}{n} -1

,

Θ

Λ

ℓ

(
C
)

\Theta _{\Lambda _{\ell }} (C)

determines the code

C
C

uniquely, iii) for

ℓ
>

2
(
n
+
1
)
(
n
+
2
)

n

−
1

\ell > \frac {2(n+1)(n+2)}{n} -1

, there is a positive dimensional family of symmetrized weight enumerator polynomials corresponding to

Θ

Λ
ℓ

(
C
)

\Theta _{\Lambda _\ell }(C)

.
Homogeneous Hilbert scheme
Authors: Álvarez Amelia , Sancho Fernando , Sancho Pedro
Published: December 2007

Let

S
S

be a locally noetherian scheme and

R
R

an

N

\mathbb N

-graded

O

S

\mathcal O_S

-algebra of finite type. We say that

X
=
Spec
⁡
R

X=\operatorname {Spec}R

is a homogeneous variety over

S
S

. In this paper we prove that the functor
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="StartLayout 1st Row 1st Column ModifyingBelow upper H o m upper H i l b With bar Subscript upper X slash upper S Baseline colon StartBinomialOrMatrix Locally noetherian Choose upper S hyphen schemes EndBinomialOrMatrix 2nd Column a m p semicolon right squiggle arrow Sets 2nd Row 1st Column upper T 2nd Column a m p semicolon right squiggle arrow StartLayout 1st Row closed subschemes of upper X times Subscript upper S Baseline upper T 2nd Row flat and homogeneous over upper T EndLayout EndLayout">

HomHilb
_

X

/

S

:

[

Locally noetherian

S

-schemes

]

a
m
p
;
⇝
Sets

T

a
m
p
;
⇝

closed subschemes of 

X

×
S

T

flat and homogeneous over 

T

\begin{align*} \underline {\operatorname {HomHilb}}_{X/S} \colon \left [ \begin {array}{l} \text {Locally noetherian}\\ \text {$S$-schemes} \end{array} \right ] & \leadsto \text {Sets}\\ T & \leadsto \begin {array}{l} \text {closed subschemes of $X\times _ST$}\\ \text {flat and homogeneous over $T$} \end{array} \end{align*}

is representable by an

S
S

-scheme that is a disjoint union of locally projective schemes over

S
S

. The proof is very simple, and it only makes use of the theory of graded modules and standard flatness criteria. From this, one obtains an elementary construction (which does not make use of cohomology) of the ordinary Hilbert scheme of a locally projective

S
S

-scheme.
A prospective longitudinal population‐based study of clinical miscarriage in an urban Swedish population
Authors: Blohm F , Fridén B , Milsom I
Published: December 2007

Objective  To describe the incidence of clinical miscarriage and to investigate the factors influencing the occurrence of clinical miscarriage.

Design  Prospective study with both cross‐sectional and longitudinal comparisons.

Setting  City of Göteborg, Sweden.

Population  Population‐based study in cohorts of 19‐year‐old women followed longitudinally.

Main outcome measures  Incidence of miscarriage and pregnancy outcome.

Material and methods  A postal questionnaire was sent to women born in 1962 and resident in the city of Göteborg in 1981 (n= 656) regarding pregnancy outcome, clinical miscarriage and other reproductive health factors. Responders in 1981 were contacted again and requested to answer a similar questionnaire every fifth year up to 2001. The same process was repeated in 1991 with women born in 1972 (n= 780) with follow up of these responders in 1996 and 2001. A third cohort of 19‐year‐old women born in 1982 (n= 666) was interviewed in 2001. The self‐reported pregnancy data were verified from hospital files.

Results  Complete data were available for 341 women born in 1962 and assessed up to the age of 39 years (ever pregnant, n= 320, 94%). There were in total 887 pregnancies (live birth, n= 590, 67%; miscarriage, n= 108, 12%; legal abortion, n= 173, 20% and ectopic pregnancy, n= 16, 2%). Of the 320 ‘ever pregnant’ women, 80 women (25%) had experienced a miscarriage. 76.3% had experienced one miscarriage, 16.3% had two miscarriages and 7.4% had three or more miscarriages. The clinical miscarriage rates in women at different ages were as follows: 20–24 years 13.5%, 25–29 years 12.3%, 30–34 years 10.3% and 35–39 years 17.5%. The corresponding miscarriage rate in the 1972 cohort followed from 19 to 29 years of age was 11%, and in the 1982 cohort assessed at 19 years of age, the miscarriage rate was 9%. No risk factor for miscarriage could be reliably identified.

Conclusions  Clinical miscarriage constituted 12% of all pregnancies, and one in four women who had been pregnant up to 39 years of age had experienced a miscarriage. Three or more miscarriages were experienced by 7.4%. The occurrence of a miscarriage was not influenced by the order of the pregnancy.
Commentary: Polycystic ovary syndrome: a transgenerational evolutionary adaptation
Authors: Shaw LMA , Elton S
Published: December 2007

Polycystic ovary syndrome has a common association with anovulatory infertility, while the physical symptoms are often associated with the increased androgens that are part of the endocrine profile. There is a well‐recognised association with lipid and glucose metabolism anomalies and, when undergoing ovulation induction, ovarian hyperstimulation syndrome. This common condition is familial, but a contributory gene has yet to be found. The question of why a gene that predisposes to anovulation, diabetes and heart disease might have perpetuated so frequently is addressed. Three hypotheses for evolutionary advantage are discussed. The food deprivation hypothesis considers the role of the observed increase in ovulation when women with the condition lose weight in relation to seasonality. The refeeding hypothesis considers the androgenic and slightly enhanced anabolic metabolism in relation to periods of privation and the advantage of preferential early ovulation when refeeding after a period of privation. The transgenerational privation hypothesis considers the effect of persistent, severe, yet subfatal privation on individuals both in utero and throughout life. While an androgenic, anabolic state would improve efficiency in the use of food for protein synthesis and fat storage, benefiting the fetus both in relation to its in utero development and neonatal survival, survival and reproductive capacity as an adult benefits by a genotype expressing itself in women of successive generations.
A longitudinal study of sexual functioning in women referred for colposcopy: a 2‐year follow up
Authors: Hellsten C , Lindqvist PG , Sjöström K
Published: December 2007

Objective  To elucidate psychosexual problems in women referred for colposcopy after an abnormal cervical smear and a 6‐month and 2‐year follow up.

Design  Prospective study.

Setting  Department of Gynaecology, Malmö University Hospital, Sweden.

Population  One hundred consecutive women referred for colposcopy for the first time subsequent to receiving notification of an abnormal cervical smear.

Methods  The women completed the State‐Trait Anxiety Inventory, a psychosexual questionnaire and had one psychosocial interview prior to colposcopy at all three visits.

Main outcome measures  Depending upon the result of the cervical biopsy, women had either a loop electrosurgical excision procedure (LEEP) or not. Psychosexual variables, anxiety measures, and psychosocial variables were used to estimate sexual functioning at the beginning of the study and at follow up. Differences in sexual functioning between LEEP and non‐LEEP groups were estimated.

Results  ‘Spontaneous interest in sex’, ‘frequency of intercourse’, and ‘sexual arousal’ were reported to be statistically significant lower at 6 months compared with the first visit, and at 2 years, ‘spontaneous interest in sex’ and ‘frequency of intercourse’ still remained low. There was no difference in sexual functioning between the LEEP and non‐LEEP groups at follow up.

Conclusions  Two years after referral for colposcopy, women still had an effect on sexual functioning, that is, lesser ‘spontaneous interest’ and decreased ‘frequency of intercourse’. We found no support for a relationship between treatment of cervical intraepithelial neoplasia by LEEP and deterioration in sexual functioning.
Hormone replacement therapy use and variations in the risk of breast cancer
Authors: Opatrny L , Dell’Aniello S , Assouline S , Suissa S
Published: December 2007

Objective  To determine the effect of different types and formulations of hormone replacement therapy (HRT) on the risk of breast cancer in postmenopausal women.

Design  Population‐based case–control study.

Setting  UK, 1988–2004.

Participants  Women 50–75 years between 1998 and 2004.

Main outcome measures  Breast cancer incidence to estimate the rate ratio (RR) associated with use of various HRTs over a 30‐year period.

Results  We identified 6347 incident cases of breast cancer that were matched with 31 516 controls. Cases were on average 61 years at diagnosis and 22% had undergone a hysterectomy. The rate of breast cancer was increased with the use of opposed estrogens in oral form (adjusted RR 1.38; 95% CI 1.27–1.49) in contrast to patch form (RR 1.08; 95% CI 0.81–1.43). This rate was similarly elevated with both continuous (RR 1.29; 95% CI 1.07–1.56) and sequential (RR 1.33; 95% CI 1.21–1.46) forms of opposed estrogen. The rate of breast cancer was not increased among exclusive users of unopposed estrogens (RR 0.97; 95% CI 0.86–1.09) or of tibolone (RR 0.86; 95% CI 0.65–1.13). Users of tibolone who had switched from opposed estrogens, however, had an elevated rate (RR 1.29; 95% CI 1.09–1.52). The rate of breast cancer increased by 25% (95% CI 20–30%) with every ten prescriptions of orally administered opposed estrogen.

Conclusions  The risk of breast cancer varies with the formulation and preparation of HRT. Opposed estrogens (progesterone–estrogen) in oral form are associated with an increased risk of breast cancer, which increases with use. Transdermal opposed estrogens, unopposed estrogens and tibolone do not increase this risk. However, this study is an observational study that carries risks of various biases, and thus the findings need to be interpreted with caution.
Intraoperative Transesophageal Echocardiographic Imaging of Intrapulmonary Tunnel Repair for Anomalous Left Coronary Artery Originating from the Pulmonary Artery
Authors: RYCHIK JACK , JACOBS MARSHALL L.
Published: December 2007

Reestablishment of aortic flow to the coronary vasculature is the optimal treatment for anomalous origin of the left coronary artery originating from the pulmonary artery (ALCA). We performed intraoperative transesophageal echocardiography (TEE) in five patients (median age 10 months; range 1.5–36 months) who underwent revascularization of the left coronary artery without coronary mobilization by creation of an aortopulmonary window and intrapulmonary tunnel to the os of the anomalous vessel. Tunnel geometry as well as supravalvar pulmonary course were well imaged. Revascularized left coronary artery antegrade flow from the aorta was documented in all via color and pulse wave Doppler. A peribaffle leak (left‐to‐right shunt) was noted in 2 of the 5 patients, however its presence did not influence left coronary artery flow or clinical outcome. Intraoperabve TEE is helpful in assessing adequacy of repair and documenting antegrade aortic flow in the left coronary artery after intrapulmonary tunnel repair for ALCA.
Digital Storage and Analysis of Color Doppler Echocardiograms
Authors: CHANDRA SHALABH , THOMAS JAMES D.
Published: December 2007

Color Doppler flow mapping has played an important role in clinical echocardiography. Most of the clinical work, however, has been primarily qualitative. Although qualitative information is very valuable, there is considerable quantitative information stored within the velocity map that has not been extensively exploited so far. Recently, many researchers have shown interest in using the encoded velocities to address the clinical problems such as quantification of valvular regurgitation, calculation of cardiac output, and characterization of ventricular filling. In this article, we review some basic physics and engineering aspects of color Doppler echocardiography, as well as drawbacks of trying to retrieve velocities from video tape data. Digital storage, which plays a critical role in performing quantitative analysis, is discussed in some detail with special attention to velocity encoding in DICOM 3.0 (medical image storage standard) and the use of digital compression. Lossy compression can considerably reduce file size with minimal loss of information (mostly redundant); this is critical for digital storage because of the enormous amount of data generated (a 10 minute study could require 18 Gigabytes of storage capacity). Lossy JPEG compression and its impact on quantitative analysis has been studied, showing that images compressed at 27:1 using the JPEG algorithm compares favorably with directly digitized video images, the current goldstandard. Some potential applications of these velocities in analyzing the proximal convergence zones, mitral inflow, and some areas of future development are also discussed in the article.
Quantitative Assessment of Simulated Regurgitant Flow Using Direct Digital Acquisition of Doppler Color Flow Images
Authors: GRAYBURN PAUL A. , CIGARROA CARLOS G. , WILLETT DUWAYNE L. , BRICKNER M. ELIZABETH
Published: December 2007

Analysis of jet momentum and proximal isovelocity surface area (PISA) have been shown to be accurate in quantitating regurgitant flow for axisymmetric free jets. However, eccentric jets directed against chamber walls are often encountered in clinical practice and could confound the assessment of regurgitant flow. Thus, we used direct digital color flow mapping to calculate flow by the momentum method and PISA in a flow model. Steady flow jets were driven through a 2‐mm round orifice at flow rates of 3, 6, 9, 12, 15, and 20 mL/sec. Jets were directed centrally and against the lateral wall of a 150 mL chamber. The raw data from a 3.25/2.5 MHz transducer (Vingmed CFM 750) was digitally transferred to a Macintosh IIci computer for analysis of the velocities comprising the jets. By linear regression, PISA was accurate in assessing flow for both free jets and wall jets (r2= 0.98) with regression lines approximating unity. The momentum method was highly accurate for free jets (r2= 0.98) but systematically underestimated flow for wall jets (r2 ‐ 0.70, y = 0.21x + 0.88). Thus, analysis of simulated regurgitant flow using digital display of velocities encoded in the color flow jet is accurate for free jets by both the PISA and momentum techniques. In wall jets, the momentum technique underestimates flow because the requirement for jet axisymmetry is not met.
Quantitative Stress Echocardiography in Chronic Aortic and Mitral Regurgitation
Authors: KLUES HEINRICH G. , RÜDELSTEIN RALPH , WACHTER MARTIN V. , KLEINHANS EDUARD , FLEIG ALFONS , JOACHIM CARSTEN , BÜLL UDALRICH , HANRATH PETER
Published: December 2007

It was the purpose of the present study to prove the feasibility and reliability of quantitative stressechocardiography as an alternative method to radionuclide angiography (RNA) in chronic regurgitant valvular lesions. Echocardiography and RNA are most commonly used to obtain various left ventricular (LV) morphometric and functional parameters that have been postulated to predict long‐term prognosis in patients with aortic and mitral valvular regurgitation. Supine bicycle ergometry with a workload ranging from 25–250 Watts was used to evaluate stress dependent LV volumes and ejection fractions (EFs) in patients with pure aortic (n = 18) and mitral regurgitation (n = 14). Most patients (23/32) underwent simultaneous right heart catheterization. Echocardiographic EFs were validated by RNA with good correlations (r = 0.81, P < 0.01). Patients with aortic regurgitation and functional class I/II (9), had a significant increase in EF during exercise (60%–67%, P < 0.001) and a reduction in end‐systolic volume (71–52 mL, P < 0.01). In comparison, patients with class III symptoms (9), had a drop in EF (53%–49%, P < 0.01), had larger baseline end‐systolic volume (104 mL, P = NS), which did not decrease during stress (104 vs 107 mL, P = NS). In patients with chronic mitral regurgitation baseline and exercise EF did not differ between class I/II (6) and class III (8), however, mildly symptomatic patients increased from 57%–67%, (P < 0.01) versus patients in class III (65% vs 69%, P = NS). Stroke volume index was not different at baseline (44 vs 33 mL/m2, P = NS); however, there were significant differences during exercise (70 vs 41 mL/m2, P = 0.05). Quantitative stress‐echocardiography is a noninvasive and safe alternative method to RNA, which allows reliable calculation of stress dependent LV volumes and EF. Determination of end‐systolic volumes may be of additional prognostic value. The combination of a high baseline EF and low stroke volume index with the inability to improve during exercise might reflect early stages of impaired LV function in patients with severe mitral regurgitation.
Resolution of Thrombi in Left Atrial Appendage Aneurysm
Authors: KARATASAKIS GEORGE T. , BELDEKOS DEMETRIOS I. , MAKOS GEORGE S. , SFIRAKIS PETROS D. , COKKINOS DENNIS V.
Published: December 2007

Atrial appendage aneurysm is a rare cardiac disease and may be complicated by embolic events and rhythm disturbances. We describe a case of a congenital left atrial aneurysm presenting with a cere‐brovascular accident in a 57‐year‐old female. The diagnosis was made by transesophageal echocardiography, which revealed the presence of intraaneurysmal thrombi. The patient initially received anticoagulant therapy and the thrombi were resolved. Subsequently, she was successfully operated on and the aneurysm was removed. This is the first report of thrombi resolution in a left atrial appendage aneurysm.
Mirror Image from a Left Atrial Line Mimicking a Catheter in the Left Ventricle During Transesophageal Echocardiography
Authors: POTHULA ASWARTHA R. , NANDA NAVIN C. , AGRAWAL GOPAL , KREMKAU FREDERICK W. , TIRTAMAN CONNY , BHATNAGER SUDHIR
Published: December 2007

We describe a case report where a left atrial catheter inserted intraoperatively produced an artifact, which mimicked a catheter in the left ventricle during transesophageal echocardiographic examination.
Quantitative Echocardiographic Assessment of Left Ventricular Shape
Authors: UR REHMAN AFZAL , D'CRUZ IVAN
Published: December 2007

Left ventricular (LV) shape has hitherto received little attention from echocardiographers; systematic quantitative observations on LV shape, apart from LV volume, wall thickness or function, have been attempted only recently. In this article, we focus on assessment of normal LV shape and changes in overall LV chamber configuration in cardiomyopathic and other dysfunctional left ventricles. The topic of LV shape of hypertrophic LV chambers is also addressed. LV shape descriptors comprise ratios of various LV measurements to each other; their values in normal and abnormal LV chambers, as set forth in recent work from our laboratory and others, are summarized. Cardiologists, including echocardiographers, are not generally aware of the various geometric approaches to quantifying chamber shapes. These are briefly described, with comments on their relative suitability for application to LV shape evaluation.
Echocardiographic Assessment of Dynamic Changes in Left Ventricular Shape
Authors: TISCHLER MARC D.
Published: December 2007

Changes in resting left ventricular shape have been related to underlying left ventricular dysfunction and may precede detectable hemodynamic abnormalities. The significance of dynamic changes in left ventricular shape has only recently been examined. In patients with systolic left ventricular dysfunction, dynamic changes in heart shape correlate strongly with exercise duration. Patients whose ventricles develop a more spheric left ventricular shape during exercise have diminished exercise capacity compared to patients whose ventricles become more ellipsoidal. In patients having mitral valve surgery for chronic, severe mitral regurgitation, mitral valve repair results in improved rest and exercise ejection indexes when compared to valve replacement, primarily due to a marked reduction in end‐systolic stress and maintenance of a more ellipsoidal left ventricular shape. Potential mechanisms for these observations are discussed.
The Five View Technique for Stress Echocardiography: A Description and Evaluation of Segmental Imaging and Reported Angiographic Data
Authors: PHILLIPS ROBERT A. , MEURS MICHELLE R. , WAITES JONATHAN H.
Published: December 2007

Stress echocardiography is an accurate means of evaluating ischemic heart disease with sensitivities and specificities equivalent to alternate modalities. The sensitivities to disease of vessels with posterior wall distribution are, however, significantly lower. Studies establishing these figures have used a 4 view digital imaging technique as standard. This study aimed to determine if the use of a 5 view template (4 views plus an apical 3 chamber (3ch) view) significantly improved stess echo results. One hundred consecutive stress echocardiograms using a 5 view format were analyzed by two independent observers. Nine thousand regional wall segments were graded quantitatively and qualitatively and comparisons were made between the 4 and 5 view techniques. Reported angiographic sensitivities of the two techniques were analyzed and compared to the segmental imaging data. The 5 view template was found to increase overall segmental imaging by 30% and imaging of lateral and posterior walls was increased by 50% while the additional poststress cycle was acquired in under 13 seconds. Five view studies reported increased mean sensitivitities to left anterior descending coronary artery (LAD) disease of 29.7%, right coronary artery (RCA) disease of 25.7%, and circumflex coronary artery (Cx) disease of 51.6%. This study found that the 5 view technique significantly increased left ventricular segmental imaging, particularly of the posterior and lateral walls, and is associated with increased angiographically determined sensitivity, particularly for vessels with posterior wall distribution when compared to the 4 view technique.
Atrial Septal Aneurysm Does Not Predispose to Stroke in the Immediate Postoperative Period Following Cardiac Surgery
Authors: JADHAV PRAVEEN , KAMALESH MASOOR , RAJU VEENA , BURGER ANDREW J.
Published: December 2007

The postoperative period following cardiac surgery is associated with an increased incidence of cerebrovascular events. Previous retrospective studies have suggested that atrial septal aneurysms (ASAs) are associated with embolic strokes ranging in incidence from 20%–52%. The purpose of the study was to investigate whether patients with ASA undergoing cardiac surgery have increased risk for strokes in the immediate postoperative period. Of 1626 consecutive patients undergoing transesophageal echocardiography during cardiac surgery over a 44‐month period, 80 patients were identified to have ASA (incidence 4.9%). Patients were followed during their entire hospital stay for development of any neurological event. Any patient with a suspicion of neurological event had a detailed neurological history, examination, and, if necessary, a CT scan or MRI study. Most patients were started on aspirin postoperatively. None of the patients experienced a cerebrovascular event or systemic embolization during this period. Thus, the presence of isolated ASA may not pose an additional risk for cerebrovascular events during postoperative period.
Modifications of Oxygen Saturation During Transesophageal Echocardiography
Authors: MACOR FRANCO , ZOTTAREL GABRIELLA , ANTONINI‐CANTERIN FRANCESCO , MIMO RENATA , PAVAN DANIELA , CERVESATO EUGENIO , NICOLOSI GIANLUIGI , ZANUTTINI DOMENICO
Published: December 2007

The present study was designed: (1) to establish the effects of transesophageal echocardiography (TEE) on arterial oxygen saturation (SAO2%); (2) to verify the possible clinical consequences of this phenomenon; and (3) to study the possibility of predicting modifications of SAO2% by clinical or hemodynamic variables or by specific factors related to the TEE procedure. We prospectively studied 116 unselected patients, aged 61 ± 12 years, who underwent diagnostic TEE for various clinical indications. Thirty‐seven patients had mitral valve disease, 19 aortic valve disease, 14 combined mitroaortic disease, 8 congenital heart disease, and 38 other cardiovascular diseases. Eight patients were affected by chronic obstructive pulmonary disease. Ninety‐seven patients were sedated by 4 ± 2 mg of diazepam IV SAO2% (5‐min average) (Ohmeda Biox 3700 pulse oxymeter finger probe), heart rate (HR), and blood pressure (BP) were considered during baseline transthoracic examination, after pharmacological sedation but before the introduction of the probe, and finally during TEE. Neither clinical complications nor major arrhythmias were observed. Baseline SAO2%, HR and BP were, respectively, 93.6 ± 3.3%, 76 ± 14 beats/min, and 129 ± 20/75 ± 10 mmHg. Pharmacological sedation did not modify SAO2%, HR, and BP (P > 0.1). During TEE a small but significant reduction in SAO2% by an average of 1.2 ± 3.2% was observed (P < 0.005), as well as a small and significant increase in HR by an average of 3 ± 10 beats/min (P < 0.01). BP did not change significantly (P > 0.1 for both systolic and diastolic). The changes of SAO2% and HR were not interrelated and were not related to the duration of the procedure and to any of the clinical and hemodynamic variables taken into consideration. TEE can induce a small but significant drop in SAO2% and a small increase in HR even without any clinical relevance. No clinical or hemodynamic variable or specific factors related to the TEE procedure were related to these changes.
Echocardiographic Detection of Two Distinct Left Ventricular Pseudoaneurysms After Mitral Valve Replacement
Authors: TAKEUCHI MASAAKI , KUROIWA AKIO
Published: December 2007

Left ventricular pseudoaneurysm after mitral valve replacement (MVR) is a rare but clinically significant complication. We report a case of two distinct left ventricular pseudoaneurysms after re‐MVR, which was correctly diagnosed by two‐dimensional echocardiography, and subsequently confirmed by surgery.
Transesophageal Echocardiographic Diagnosis of Left Atrial Wall Dehiscene
Authors: HOWARD JEFFREY , AGRAWAL GOPAL , NANDA NAVIN C.
Published: December 2007

Six months following Carbomedics mitral and aortic valve replacement, multiplane transesophageal echocardiography performed (TEE) in a 49‐year‐old black gentleman showed a prominent 1.0‐cm linear echo protruding into the left atrium at the mid‐interatrial septal level distal to the sewing ring. Plane angulations at 105 and 111 degrees demonstrated the linear echo to be related to left atrial wall dehiscence indicated by the presence of a cavitary defect at the same level. At the time of surgery, a 1.0 cm‐paravalvular defect and dehiscence of the left atrial wall distal to the sewing ring 2.0 centimeters anterior to the posteromedial commisure were found.
Echocardiographic Assessment of Regional and Global Left Ventricular Function: Wall‐Motion Scoring in Parasternal and Apical Views Versus Apical Views Alone
Authors: ALI SAMIR , EGEBLAD HENRIK , STEENSGÅRD‐HANSEN FRANK , SAUNAMÄKI KARI , CARSTENSEN STEEN , HAUNSØ STIG
Published: December 2007

The aim of the study was to examine the value of echocardiographic wall‐motion scoring in apical views as compared to a conventional combination of apical and parasternal views. In 50 consecutive patients referred to coronary arteriography for potential revascularization, echocardiographic digital image loops of the left ventricle (LV) were recorded in parasternal long‐ and short‐axis views and in apical long‐axis, two‐, and four‐chamber views. Eight of 16 standardized LV segments appear both in the apical and in the parasternal views (group 1 segments). The remaining eight segments are visualized in the apical views only (group 2). Using a cross‐over design, two cardiologists independently performed regional wall‐motion scoring based on apical views, respectively, based on the combination of parasternal and apical views. Using the conventional approach (parasternal and apical views) 98% of the total 800 segments were scored as compared to 95% when using the mere apical approach (P < 0.05); 94% of the 800 segments were scored from both approaches. The regional wall‐motion score was identical in 76% of group 1 segments and in 77% of group 2 segments. It diverged, at most, one score in 94% of group 1 segments and in 91% of group 2 segments (P > 0.05). LV ejection fraction (EF) calculated on the basis of average wall‐motion score exclusively assessed from the apex differed little from angiographic EF (mean difference 2.0%, 95% confidence limits ± 6.6%). Intraobserver variability of wall‐motion scores (n = 25 patients) was small and almost identical for the two cardiologists. Similarly, interobserver variability was small and identical for apical views and conventional views. We conclude that there is no substantial loss of information when echocardiographic evaluation of regional and global left ventricular function is performed solely from the apical approach.