bluuebunny/crossref_metadata_2025 huggingface dataset:
Seismic anisotropy in sedimentary rocks, part 1: A single‐plug laboratory method
Authors: Wang Zhijing
Published: September 2002

A single‐plug method for measuring seismic velocities and transverse isotropy in rocks has been rigorously validated and laboratory tested. The method requires only one sample to measure the velocities needed to derive the five independent elastic constants for transversely isotropic materials. In this method, piezoelectric transducers are fitted to the top, bottom, and sides of the cylindrical sample. Laboratory velocity and anisotropy can be measured as functions of pressure, temperature, fluid saturation, and fluid displacement. Because this method uses a horizontal core plug that has much higher permeability than a vertical core plug, it is especially suitable for low‐permeability shale measurements. It reduces the sample preparation and velocity measurement time by more than two‐thirds.
Detection of a recent earthquake fault by the shallow reflection seismic method
Authors: Wang Chien‐Ying
Published: September 2002

The 1999 Chi‐Chi earthquake in Taiwan was a relatively unique seismic event which activated the Chelungpu thrust fault with extraordinarily large surface ruptures up to 9.8 m horizontally and 5.6 m vertically. The fault is 80 km long, lying mostly in a north–south direction and with a reverse thrust dipping shallowly to the east. For this paper we used the shallow reflection seismic method (a small‐scale method) to map this active fault (a large‐scale structure) and provide evidence in support of the thin‐skinned thrust model for this earthquake fault. The investigation is comprised of two parts. The first concentrates on the northern portion of the fault where the fault trace was bent 70° to the northeast and was accompanied by abnormally large ground displacements and damage. The seismic sections obtained are of good quality and can be used to explore the detailed faulting mechanism. The second part aims to find the gross features of the 60 × 20‐km fault surface using limited shallow seismic measurements (about 50 seismic lines), incorporating the thin‐skinned thrust concept. This is a test to examine the feasibility of using a small‐scale economical method to study a big structure. The results are quite plausible.
The GPR refraction method
Authors: Bohidar Rabi N. , Hermance John F.
Published: September 2002

Refracted phases have been a recognized feature in wide‐angle common midpoint (CMP) and common shotpoint (CSP) ground‐penetrating radar (GPR) surveys for many years, but historically their use has been limited and overshadowed by conventional reflection profiling techniques. In truth, the GPR refraction method holds great promise, as we show using four field examples from three sites in the northeastern United States. Typical refractors are shallow bedrock or coarse‐grained unconsolidated sediments (where the dielectric constant K ≈ 6–7) beneath partially saturated fine‐grained sand or silt (K ≈ 15–16). Under appropriate conditions, refracted phases can be detected readily at transmitter–receiver (Tx–Rx) offsets of >15 m and from depths of >2 m.

Adapting procedures from refraction seismology, we interpret GPR data from reversed CSP soundings using dipping planar interface models and delay time analyses. Results from the two approaches are quite consistent, further corroborated at one of the sites by a GPR reflection profile and directly verified by a series of hammer‐driven probes. In addition to refractions from higher velocity layers in the subsurface, the air refracted phase (the ubiquitous phase refracted from the air–earth interface) can provide important constraints on interpreting the subsurface—particularly useful when attempting to resolve a shallow interface (depth ≤ 0.5 m) whose GPR signature might be masked by interacting phases at early traveltime and small transmitter–receiver offsets.

Finally, a cautionary note for interpreting conventional reflection profile data when delineating a higher velocity interface at a depth that might be on the order of the antenna separation or less. Since the refracted phase arrives earlier than the reflected phase for Tx–Rx offsets beyond the critical distance, in certain cases the first break on a reflection radargram may actually be a refraction. CMP or CSP soundings in support of conventional GPR profiles can resolve such concerns.
Prediction of 3‐D fluid permeability and mudstone distributions from ground‐penetrating radar (GPR) attributes: Example from the Cretaceous Ferron Sandstone Member, east‐central Utah
Authors: Corbeanu Rucsandra M. , McMechan George A. , Szerbiak Robert B. , Soegaard Kristian
Published: September 2002

A 3‐D fluid permeability distribution is estimated inside a channel sandstone reservoir analog in the Cretaceous Ferron Sandstone fluvio‐deltaic complex in east‐central Utah from ground‐penetrating radar (GPR) attributes. Fluid permeability measurements at 5 cm spacing along four boreholes and one pseudohole section at the adjacent cliff face are used together with instantaneous amplitude and frequency attributes of GPR data to predict fluid permeabilities away from the measured vertical transects and to delineate the distribution and geometry of mudstone layers inside the reservoir analog. Statistically significant relationships are determined between the well data (fluid permeability and mudstone content) and the GPR attributes. These calibrations are applied to the entire GPR volume to estimate the 3‐D fluid permeability variation and the lateral development of mudstone units.

Measured and predicted fluid permeabilities range from 0.1 to 290 md. One of the five units considered contained no mudstone layers; cores from the other four units contained 18–42% mudstone and mudstone intraclast conglomerate. The mudstone content is estimated to be 8% by volume in these four units. Variograms show that the mudstone bodies fall into two main categories; most are 2.3–3.5 m in extent in the maximum correlation direction, with anisotropies of 0.4 to 0.7. A few ribbonlike mudstone bodies are also present, with 20‐ to 30‐m extents in the maximum correlation direction and with anisotropies of ∼0.1.
Aquifer heterogeneity from SH‐wave seismic impedance inversion
Authors: Jarvis Kevin D. , Knight Rosemary J.
Published: September 2002

We collected SH‐wave seismic reflection data over a shallow aquifer in southwestern British Columbia to investigate the use of such data in hydrogeologic applications. We used this data set in developing a methodology that uses cone penetrometer data as an integral part of the inversion and interpretation of the seismic data. A Bayesian inversion technique converts the seismic amplitude variations to velocity variations, honoring the probabilities of the priors and adhering to a geologically reasonable sparseness criterion. Velocity measurements acquired with the cone penetrometer provide velocity profiles and vertical seismic profiling (VSP) data, all of which are valuable in properly constraining the Bayesian inversion. The differentiation of lithologies (in this data set, sand and clay) is accomplished by first using a normalization procedure to remove the impact of effective stress, which dominates the velocity variation in the upper 10 to 20 m. The final transformation of seismic velocities to void ratio for the sand‐dominated regions is made using laboratory‐derived measurements; it provides an image of the heterogeneity of the near‐surface aquifer.
Multicomponent stacking‐velocity tomography for transversely isotropic media
Authors: Grechka Vladimir , Pech Andres , Tsvankin Ilya
Published: September 2002

Accurate estimation of the velocity field is the most difficult step in imaging of seismic data for anisotropic media. Here, the velocity‐analysis problem is examined for the most common anisotropic model of sedimentary formations—transverse isotropy (TI) with arbitrary orientation of the symmetry axis. We show that supplementing wide‐azimuth reflected PP data with mode‐converted (PS) waves yields more stable estimates of the anisotropic coefficients and, in many cases, helps to constrain the model in depth.

An important processing step preceding the inversion is computation of the traveltimes of the pure SS‐waves from those of the PP‐, and PS‐waves based on a technique recently developed by Grechka and Tsvankin. This procedure allows us to replace PS‐wave moveout, which is generally asymmetric with respect to zero offset, with the symmetric (hyperbolic on short spreads) moveout of the pure SS reflections. Then, generalizing the algorithm previously suggested for PP data, we develop a joint tomographic inversion of the normal‐moveout (NMO) ellipses and zero‐offset traveltimes of PP‐ and SS‐waves.

Application of the method to wide‐azimuth PP and PS reflections from a dipping interface beneath a homogeneous TI layer shows that for a range of reflector dips and tilt angles of the symmetry axis, it is possible to build the anisotropic velocity field in the depth domain. We also extend our inversion procedure to layered TI media with curved interfaces and study its stability in the presence of noise and heterogeneity.
Traveltime and amplitude calculation using a perturbation approach
Authors: Shin Changsoo , Marfurt Kurt J. , Park Kwon Gyu , Min Dong‐Joo , Yoon Kwangjin , Yang Dongwoo , Ha Taeyoung , Ko Seungwon , Kim Wonsik , Hong Soonduk
Published: September 2002

Accurate amplitudes and correct traveltimes are critical factors that govern the quality of prestack migration images. Because we never know the correct velocity initially, recomputing traveltimes and amplitudes of updated velocity models can dominate the iterative prestack migration procedure. Most tomographic velocity updating techniques require the calculation of the change of traveltime due to local changes in velocity. For such locally updated velocity models, perturbation techniques can be a significantly more economic way of calculating traveltimes and amplitudes than recalculating the entire solutions from scratch.

In this paper, we implement an iterative Born perturbation theory applied to the damped wave equation algorithm. Our iterative Born perturbation algorithm yields stable solutions for models having velocity contrasts of 30% about the initial velocity estimate, which is significantly more economic than recalculating the entire solution.
Velocity analysis in the presence of amplitude variation
Authors: Sarkar Debashish , Baumel Robert T. , Larner Ken L.
Published: September 2002

Conventional semblance velocity analysis is equivalent to modeling prestack seismic data with events that have hyperbolic moveout but no amplitude variation with offset (AVO). As a result of its assumption that amplitude is independent of offset, this method might be expected to perform poorly for events with strong AVO—especially for events with polarity reversals at large offset, such as reflections from tops of some class 1 and class 2 sands. We find that substantial amplitude variation and even phase change with offset do not compromise the conventional semblance measure greatly. Polarity reversal, however, causes conventional semblance to fail.

The semblance method can be extended to take into account data with events that have amplitude variation, expressed by AVO intercept and gradient (i.e., the Shuey approximation). However, because of the extra degrees of freedom introduced in AVO‐sensitive semblance, resolution of the estimated velocities is decreased. This is because the data can be modeled acceptably with a range of combined erroneous velocity and AVO behavior.

To address this problem, in addition to using the Shuey equation to describe the amplitude variation, we constrain the AVO parameters (intercept and gradient) to be related linearly within each semblance window. With this constraint we can preserve velocity resolution and improve the quality of velocity analysis in the presence of amplitude and even polarity variation with offset. Results from numerical tests suggest that the modified semblance is accurate in the presence of polarity reversals. Tests also indicate, however, that in the presence of noise, the signal peak in conventional semblance has better standout than does that in the modified semblance measures.
‘Men-streaming’ gender? Questions for gender and development policy in the twenty-first century
Authors: Chant Sylvia , Gutmann Matthew C.
Published: September 2002

Insofar as gender is still so often equated with women alone, the move from Women in Development to Gender in Development has changed very little. Men as a human category have always been present, involved, consulted, obeyed and disobeyed in development work. Yet men as a gendered category in a feminist sense - involving unequal power relations between men and women and between men - have rarely been drawn into development programmes in any substantial way. This paper addresses conceptual and operational obstacles to men’s involvement in gender and development, drawing on interviews with over 40 representatives of development organizations in Britain and the USA in 1999.
The macro-economic impact of disasters
Authors: Pelling Mark , Özerdem Alpaslan , Barakat Sultan
Published: September 2002

Despite 30 years of study, international development policy appears to be little closer to generating protection to vulnerable people from the preventable losses of disaster. Part of the reason for a lack of progress has been the sidelining of disaster in development studies. Disaster events have been seen as exceptional and allowed to fall outside the mainstream of development theory. In this paper we set out and use a framework that allows a more holistic accounting for the macro-economic impacts of disaster, and is a step towards a deeper integration of disasters and development.
Determinants of long-term growth in India: a Keynesian approach
Authors: Mallick Sushanta K.
Published: September 2002

This paper attempts an eclectic synthesis on long-term growth, which integrates two standard models - the neoclassical model with the endogenous growth and export-led model of growth. A vector autoregressive (VAR) model has been used for India from 1950 to 1995 using Johansen’s multivariate cointegration approach to derive latent equilibrium relationships, and the short-run error correction equations are then estimated. Two cointegrating relationships for real output and real private investment, respectively, were found. Output is determined by private investment, human capital, real interest rate and public investment. Private investment is driven by public investment, domestic credit to the private sector, real interest rate and human capital. This seems to support a McKinnon-Shaw model in the long run and a Keynesian/Structuralist view in the short run. The long-run model also validates the hypothesis that growth has not been export-led in India, rather it is growth-driven exports.
Characterization of bacterial homocitrate synthase involved in lysine biosynthesis
Authors: Wulandari Asri Peni , Miyazaki Junichi , Kobashi Nobuyuki , Nishiyama Makoto , Hoshino Takayuki , Yamane Hisakazu
Published: September 2002

In Thermus thermophilus homocitrate synthase (HCS) catalyzes the initial reaction of lysine biosynthesis through α‐aminoadipic acid, synthesis of homocitrate from 2‐oxoglutarate and acetyl‐CoA. HCS is strongly inhibited by lysine, indicating that the biosynthesis is regulated by the endproduct at the initial reaction in the pathway. HCS also catalyzes the reaction using oxaloacetate in place of 2‐oxoglutarate as a substrate, similar to citrate synthase in the tricarboxylic acid cycle. Several other properties of Thermus HCS and an evolutionary relationship of the biosynthetic pathway in the bacterium to other metabolic pathways are also described.
Naturally occurring heterologous trans‐splicing of adenovirus RNA with host cellular transcripts during infection
Authors: Kikumori Toyone , Cote Gilbert J , Gagel Robert F
Published: September 2002

The impact of viral infection on normal host RNA processing remains largely unexplored. We postulated that the high abundance of virally derived nuclear RNA in infected cells could impact host cell RNA splicing and viability. To test for aberrant RNA splicing we examined trans‐splicing following infection with the replication‐competent adenovirus mutant d11520 that lacks E1B 55 kDa protein. Trans‐splicing was observed between viral RNA and several cellular precursor mRNAs, including β‐actin and glyceraldehyde‐3‐phosphate dehydrogenase. Using a tetracycline‐inducible model system simulating viral trans‐splicing activity we observed that overexpression of a trans‐splicing RNA specifically inhibited cell proliferation. These results demonstrate that heterologous trans‐splicing occurs naturally during adenovirus infection and suggest that trans‐splicing may contribute to disruption of cell function.
Temperature‐induced selective death of the C‐domain within angiotensin‐converting enzyme molecule
Authors: Voronov Sergei , Zueva Natalia , Orlov Victor , Arutyunyan Alexander , Kost Olga
Published: September 2002

Somatic angiotensin‐converting enzyme (ACE) consists of two homologous domains, each domain bearing a catalytic site. Differential scanning calorimetry of the enzyme revealed two distinct thermal transitions with melting points at 55.3 and 70.5°C. which corresponded to denaturation of C‐ and N‐domains, respectively. Different heat stability of the domains underlies the methods of acquiring either single active N‐domain or active N‐domain with inactive C‐domain within parent somatic ACE. Selective denaturation of C‐domain supports the hypothesis of independent folding of the two domains within the ACE molecule. Modeling of ACE secondary structure revealed the difference in predicted structures of the two domains, which, in turn, allowed suggestion of the region 29–133 in amino acid sequence of the N‐part of the molecule as responsible for thermostability of the N‐domain.
Control of capillary formation by membrane‐anchored extracellular inhibitor of phospholipase A2
Authors: Chen W.M , Soria J , Soria C , Krimsky M , Yedgar S
Published: September 2002

Secretory phospholipase A2 (sPLA2) has been reported to be involved in cell proliferation in general and in endothelial cell migration, processes required for capillary formation. Subsequently, we examined the potential control of angiogenesis by sPLA2 inhibition, using a cell‐impermeable sPLA2 inhibitor composed of N‐derivatized phosphatidyl‐ethanolamine linked to hyaluronic acid. This inhibitor effectively inhibits the proliferation and migration of human bone marrow endothelial cells in a dose‐dependent manner, and suppresses capillary formation induced by growth factors involved in vascularization of tumors and of atherosclerotic plaques. It is proposed that sPLA2 inhibition introduces a novel approach in the control of cancer development and atherosclerosis.
Different roles of the IGF‐I Ec peptide (MGF) and mature IGF‐I in myoblast proliferation and differentiation
Authors: Yang Shi Yu , Goldspink Geoffrey
Published: September 2002

The physiological function of a recently cloned splice variant of insulin‐like growth factor‐I (IGF‐I; mechano growth factor (MGF)) was studied using an in vitro cell model. Unlike mature IGF‐I, the distinct E domain of MGF inhibits terminal differentiation whilst increasing myoblast proliferation. Blocking the IGF‐I receptor with a specific antibody indicated that the function of MGF E domain is mediated via a different receptor. The results provide a basis for localized tissue adaptation and helps explain why loss of muscle mass occurs in the elderly and in dystrophic muscle in which MGF production is markedly affected.
Induction of p73β by a naphthoquinone analog is mediated by E2F‐1 and triggers apoptosis in HeLa cells
Authors: Kang Kyung-Hwa , Lee Jung-Hee , Kim Keun-Cheol , Ham Seung-Wook , Kim Mie-Young , Choi Kyung Hee
Published: September 2002

Recently, p73 was identified as a structural and functional homolog of p53. The p73 protein activates the transcription of genes downstream of p53 and induces apoptosis when overexpressed in several cell lines, similar to the tumor suppressor p53. However, the extracellular stimuli and molecular mechanisms regulating p73 activity remain to be elucidated. In this paper, we present evidence that the naphthoquinone analog, 2,3‐dichloro‐5,8‐dihydroxy‐1,4‐naphthoquinone (NA), is a novel apoptotic stimulus that induces p73β expression. Treatment with NA induced the expression of p73β mRNA and protein and its downstream genes, p21 and bax, in HeLa cells. Similar results were obtained in MCF7 cells (p53+/+, p73+/+). In the MCF7 cells, p53 protein level was rather decreased by NA treatment. Overexpression of p73β led to the apoptosis of HeLa cells and enhancement of NA‐induced cell death. Expression of p73β was mediated by E2F‐1, which was activated via release from pRB after exposure of cells to NA. We additionally observed that overexpression of pRB inhibited NA‐induced apoptosis. These results imply that p53‐independent p73β‐dependent p21 expression is involved in NA‐induced apoptosis of HeLa cells.
Contribution of basic residues of the A helix of heparin cofactor II to heparin‐ or dermatan sulfate‐mediated thrombin inhibition
Authors: Hayakawa Yumiko , Hirashima Yutaka , Kurimoto Masanori , Hayashi Nakamasa , Hamada Hideo , Kuwayama Naoya , Endo Shunro
Published: September 2002

Inhibition of thrombin by heparin cofactor II (HCII) is accelerated 1000‐fold by heparin or dermatan sulfate. To investigate the contribution of basic residues of the A helix of HCII to this activation, we constructed amino acid substitutions (K101Q, R103L, and R106L) by site‐directed mutagenesis. K101Q greatly reduced heparin cofactor activity and required a more than 10‐fold higher concentration of dermatan sulfate to accelerate thrombin inhibition compared with wild‐type recombinant HCII. Thrombin inhibition by R106L was not significantly stimulated by dermatan sulfate. These results provide evidence that basic residues of the A helix of HCII (Lys101 and Arg106) are necessary for heparin‐ or dermatan sulfate‐accelerated thrombin inhibition.
The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study
Authors:   HAPO Study Cooperative Research Group
Published: September 2002

Objective: The objective of the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study is to clarify unanswered questions on associations of maternal glycemia, less severe than overt diabetes mellitus, with risks of adverse pregnancy outcome. This report describes the background and design of the HAPO Study. Methods: HAPO is a 5‐year investigator‐initiated prospective observational study that will recruit approximately 25 000 pregnant women in 10 countries. HAPO utilizes a Central Laboratory for measurement of key metabolic variables, a Clinical Coordinating Center, a Data Coordinating Center, and an independent Data Monitoring Committee. Glucose tolerance is assessed by a 75 g 2‐h OGTT at 24–32 weeks’ gestation. Results are unblinded to the woman and her caregivers if: fasting plasma glucose >5.8 mmol/l, 2‐h plasma glucose >11.1 mmol/l or any plasma glucose <2.5 mmol/l. Random plasma glucose measurement is performed at 34–37 weeks or if symptoms suggest hyperglycemia; results are unblinded for values ≥8.9 mmol/l. Sociodemographic and health history data are collected via questionnaire and medical record abstraction. Maternal blood is obtained for measurement of serum C‐peptide and hemoglobin A1c (HbA1C), cord blood for serum C‐peptide and plasma glucose, and a capillary specimen is taken between 1 and 2 h following delivery for neonatal plasma glucose. Neonatal anthropometrics are obtained, and follow‐up data are collected at 4–6 weeks post‐delivery. The primary outcomes to be assessed in relation to maternal glycemia are cesarean delivery, increased fetal size (macrosomia/LGA/obesity), neonatal morbidity (hypoglycemia), and fetal hyperinsulinism.
On the scattering of baroclinic Rossby waves by
a ridge in a continuously stratified ocean
Authors: OWEN G. W. , ABRAHAMS I. D. , WILLMOTT A. J. , HUGHES C. W.
Published: September 2002

In global ocean dynamics Rossby waves play a vital rôle in the long-term distribution
of vorticity; knowledge of the interaction between these waves and topography is
crucial to a full understanding of this process, and hence to the transportation of
energy, mixing and ocean circulation. The interaction of baroclinic Rossby waves
with abrupt topography is the focus of this study. In this paper we model the ocean
as a continuously stratified fluid for which the linear theory predicts a qualitatively
different structure for the wave modes than that predicted by barotropic or simple
layered models, even if most of the density variation is confined to the thermocline.
We consider the scattering of a westward-propagating baroclinic Rossby wave by
a narrow ridge on the ocean floor, modelled by a line barrier of infinite extent,
orientated at an arbitrary angle to the incident wave. Transmission and reflection
coefficients for the propagating modes are found using both an algebraic method and,
in the case where this breaks down, matched asymptotic expansions. The results are
compared with recent analyses of satellite altimetry data.
Linear processes in stably and unstably stratified
rotating turbulence
Authors: HANAZAKI H.
Published: September 2002

Unsteady turbulence in stably and unstably stratified flow with system rotation around
the vertical axis is analysed using the rapid distortion theory (RDT). Complete linear
solutions for the spectra, variances and covariances are obtained analytically, and
their characteristics, including the short- and long-time asymptotics and the effect
of initial conditions, are examined in detail. It has been found that the rotation
modifies the energy partition among the three kinetic energy components and the
potential energy, and the ratio of the Coriolis parameter f to the Brunt–Väisälä
frequency N, i.e. f/N, determines the final steady values of these components. The
ratio also determines the phase of the energy/flux oscillation. Depending on whether
f/N > 1 or f/N < 1, there is a phase shift of
±π/4. However, unsteady aspects are
largely dominated by stratification. This occurs because the effects of the Coriolis
parameter f appear only in the form of fk3, which vanishes for the horizontal
wavenumber components (k3 = 0), which contribute most to the energies and the
fluxes. For example, the oscillation frequency of the energies and the fluxes asymptotes
to 2N over a long time, in agreement with the stratified non-rotating turbulence. The
initial time development is also dominanted by the stratification, and the short-time asymptotics (Nt, ft
[Lt ]
1) agree with those for non-rotating stratified fluids in
the lowest-order approximation. In the special case of f = N, all the wavenumber
components oscillate in phase, leading to no inviscid decay of oscillation. This is in
contrast to the general case of f ≠ N, in which inviscid decay has been observed. For
pure rotation (f ≠ 0, N = 0), analytical solutions showed that any turbulence that
is initially axisymmetric around the rotation axis recovers exact three-dimensional
isotropy in the kinetic energy components. Comparison with previous DNS and
experiments shows that many of the unsteady aspects of the kinetic and potential
energies and the vertical density flux can be explained by the linear processes described
by RDT. Even the time development of the vertical vorticity, which would represent
the small-scale characteristics of turbulence, agrees well with DNS. For unstably
stratified turbulence, the initial processes observed in DNS and experiments, such
as the initial decay of the kinetic energy due to viscosity and the subsequent rapid
growth of the vertical kinetic energy compared to the horizontal kinetic energy, could
be explained by RDT.
Vorticity transport in a corner formed by a solid
wall and a free surface
Authors: GREGA L. M. , HSU T. Y. , WEI T.
Published: September 2002

There is a growing body of literature in which turbulent boundary layer flow along
a mixed-boundary corner formed by a vertical solid wall and a horizontal free
surface has been examined. While there is consensus regarding the existence of weak
secondary flows in the near corner region, there is some disagreement as to the exact
nature and origin of these flows. In two earlier works by the authors, evidence was
presented supporting the existence of a weak streamwise vortex which rotates in
toward the wall at the free surface and down away from the surface along the wall.
This ‘inner secondary vortex’ is accompanied by an ‘outer secondary flow’ which
transports low-momentum boundary layer fluid up along the wall and outward at
the free surface. The magnitudes of the cross-stream velocities associated with these
secondary flows were measured to be on the order of 1% of the free-stream speed.
In this paper, high-resolution DPIV measurements made in the cross-stream plane
are presented. These clearly show the inner and outer secondary flows. The cross-stream vector fields allow computation of terms in the turbulent streamwise vorticity
transport equation. These terms indicate mean vorticity transport at the free surface
associated with the outer secondary flow. In addition there appears to be a balance
between the wall-normal and free-surface-normal fluctuating vorticity reorientation
terms.
Oscillatory forcing of flow through porous
media. Part 1. Steady flow
Authors: GRAHAM D. R. , HIGDON J. J. L.
Published: September 2002

Oscillatory forcing of a porous medium may have a dramatic effect on the mean
flow rate produced by a steady applied pressure gradient. The oscillatory forcing may
excite nonlinear inertial effects leading to either enhancement or retardation of the
mean flow. Here, in Part 1, we consider the effects of non-zero inertial forces on steady
flows in porous media, and investigate the changes in the flow character arising from
changes in both the strength of the inertial terms and the geometry of the medium. The
steady-state Navier–Stokes equations are solved via a Galerkin finite element method
to determine the velocity fields for simple two-dimensional models of porous media.
Two geometric models are considered based on constricted channels and periodic
arrays of circular cylinders. For both geometries, we observe solution multiplicity
yielding both symmetric and asymmetric flow patterns. For the cylinder arrays, we
demonstrate that inertial effects lead to anisotropy in the effective permeability, with
the direction of minimum resistance dependent on the solid volume fraction. We
identify nonlinear flow phenomena which might be exploited by oscillatory forcing
to yield a net increase in the mean flow rate. In Part 2, we take up the subject of
unsteady flows governed by the full time-dependent Navier–Stokes equations.
Faecal contamination and enterotoxigenic Escherichia coli in street-vended chili sauces in Mexico and its public health relevance
Authors: ESTRADA-GARCIA T. , CERNA J. F. , THOMPSON M. R. , LOPEZ-SAUCEDO C.
Published: September 2002

The street-vended food industry provides employment and cheap ready-to-eat meals to a large proportion of the population in developing countries like Mexico, yet little is known about its role in the transmission of food borne diseases (FBD). Because of its wide consumption, street-vended chili sauces in Mexico are potential vehicles of FBD. An observational study was performed in Mexico City collecting 43 street-vended chili sauces. These sauces were prepared under poor hygienic conditions of handling and selling. Consumers add 4–8 ml of chili sauce per taco, ingest 2–5 tacos per meal and on average, 50 consumers frequent a stall per day. Seventeen (40%) samples were faecally contaminated and 2(5%) sauces harboured sufficient enterotoxigenic Escherichia coli to cause disease. We estimate that the consumption of only one of these chili sauces could result in ETEC disease in at least 21000 consumers per year, making them important potential vehicles of FBD.
Molecular epidemiology of nalidixic acid-resistant campylobacter isolates from humans and poultry by pulsed-field gel electrophoresis and flagellin gene analysis
Authors: WU T. L. , SU L. H. , CHIA J. H. , KAO T. M. , CHIU C. H. , KUO A. J. , SUN C. F.
Published: September 2002

To investigate the potential of poultry products as the source of human infections associated with quinolone-resistant campylobacters, 140 human and 75 poultry isolates of nalidixic acid-resistant campylobacters were collected between 1996 and 1998, and analysed by two molecular typing methods. By the analysis of restriction fragment length polymorphism of the flagellin gene, 33 distinct patterns were obtained, with 18 of which shared by both human (89%) and poultry (93%) isolates. By the pulsed-field gel electrophoresis of SmaI-restricted macrofragments, 105 different profiles were obtained, and 11 were found in both human (40%) and poultry (23%) isolates. When the two typing methods were combined, 112 unique genotypes were obtained, 11 of which were shared by both populations, including 53 (38%) human isolates and 14 (19%) poultry isolates. Although domestic poultry products are still important sources of the quinolone-resistant campylobacter infections in humans, there are other factors that might contribute to these increasing infections simultaneously. A more stringent policy in the use of antimicrobial agents in food animals can no longer be ignored.
Decline in epidemic of multidrug resistant Salmonella Typhi is not associated with increased incidence of antibiotic-susceptible strain in Bangladesh
Authors: RAHMAN M. , AHMAD A. , SHOMA S.
Published: September 2002

Since 1987, multidrug resistant (MDR) strains of Salmonella Typhi, resistant simultaneously to ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole, have caused epidemics of severe typhoid fever in Asia and Africa. A retrospective analysis of blood culture results (1989–96) in a Diarrhoea Treatment Centre in Dhaka, Bangladesh detected MDR strains in 0.3% (8 of 2793) of samples in 1990. The isolation rate peaked to 3.2% (240 of 7501) in 1994 (P<0.01) and decreased to 1.8% (165 of 9348) in 1995 and further to 1.0% (82 of 8587) in 1996 (P<0.01 compared to 1994) indicating the emergence and decline of MDR typhoid epidemic. Ten of 15 MDR strains tested had a 176 kb conjugative R plasmid that mediates resistance to ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole to Escherichia coli K12. Unlike MDR strains, the isolation rate (∼3.3%) of susceptible S. Typhi remained remarkably unchanged during the study. The significant decrease in isolation of MDR strains suggests that cheaper and effective first-line antibiotics may re-emerge as drugs of choice for the treatment of typhoid fever in Bangladesh.
Prevalence of antibodies to Brucella spp. and risk factors related to high-risk occupational groups in Eritrea
Authors: OMER M. K. , ASSEFAW T. , SKJERVE E. , TEKLEGHIORGHIS T. , WOLDEHIWET Z.
Published: September 2002

In a study of three high-risk occupational groups using Rose Bengal and complement fixation tests, the highest prevalence (7.1%) was found among dairy farm workers and owners in randomly selected dairy-cattle farms, followed by veterinary personnel (4.5%) and inhabitants in pastoralist areas (3.0%). There was no evidence for significant differences between the three populations. Among dairy farm workers, a higher risk was associated with the presence of sheep in the farm (OR = 13.2, CI = 2.2–76.7). In the pastoral area, a high risk was linked to having close contact with animals (OR = 6.32, CI = 0.88–∞), while a reduced risk was seen for contact with cattle (OR = 0.18, CI = 0–1.30). Symptoms suggestive of brucellosis were more commonly observed among the dairy farm workers, mainly found in the highlands, than among the pastoralist area inhabitants, where malaria is prevalent. The study documents not only the presence of serological and clinical evidence of human brucellosis, but also risk factors related to it in Eritrea, for the first time.
Quantification of Video‐Taped Images in Microcirculation Research Using Inexpensive Imaging Software (Adobe Photoshop)
Authors: Brunner Joachim , Krummenauer Frank , Lehr Hans‐Anton
Published: September 2002

Background: Study end‐points in microcirculation research are usually videotaped images rather than numeric computer print‐outs. Analysis of these videotaped images for the quantification of microcirculatory parameters usually requires computer‐based image analysis systems. Most software programs for image analysis are custom‐made, expensive, and limited in their applicability to selected parameters and study end‐points. Methods and Result: We demonstrate herein that an inexpensive, commercially available computer software (Adobe Photoshop), run on a Macintosh G3 computer with inbuilt graphic capture board provides versatile, easy to use tools for the quantification of digitized video images. Using images obtained by intravital fluorescence microscopy from the pre‐ and postischemic muscle microcirculation in the skinfold chamber model in hamsters, Photoshop allows simple and rapid quantification (i) of microvessel diameters, (ii) of the functional capillary density and (iii) of postischemic leakage of FITC‐labeled high molecular weight dextran from postcapillary venules. We present evidence of the technical accuracy of the software tools and of a high degree of interobserver reliability. Conclusions: Inexpensive commercially available imaging programs (i.e., Adobe Photoshop) provide versatile tools for image analysis with a wide range of potential applications in microcirculation research.
Autonomic responses and pain perception in Alzheimer’s disease
Authors: Rainero Innocenzo , Vighetti Sergio , Bergamasco Bruno , Pinessi Lorenzo , Benedetti Fabrizio
Published: September 2002

We analysed the effects of electrical noxious stimulation on the autonomic nervous system of Alzheimer’s disease (AD) patients who were assessed by means of the Mini Mental State Examination test (MMSE). To do this, we used electrical stimuli at two different intensities: just above pain threshold and twice pain threshold. We recorded heart rate and systolic blood pressure by using conventional electrocardiography and finger photo‐plethysmography. When a pain stimulus just above threshold was delivered, AD patients were found to have blunted autonomic responses compared to controls of the same age. Similarly, prestimulus expectation produced a less pronounced increase of the responses in AD patients compared to the controls. However, when the painful stimulus was increased to twice the pain threshold, the systolic blood pressure increase of AD patients did not differ from the controls, whereas heart rate increase was still slightly diminished. By contrast, pain perception was similar in the two groups when the stimulus was at pain threshold, whereas it was blunted in AD patients when the stimulus was twice the pain threshold. These findings show that in AD mild noxious stimulation produces blunted autonomic responses and normal pain perception, whereas strong noxious stimulation produces quasi‐normal autonomic responses and blunted pain perception. These results indicate that AD patients have an increased threshold for both autonomic activation and pain tolerance.
Acute abstinence syndrome following abrupt cessation of long‐term use of tramadol (Ultram®): a case study
Authors: Freye E. , Levy J.
Published: September 2002

We report on a patient who had taken the centrally acting analgesic tramadol for over 1 year. The compound had proven to be sufficient to treat her painful episodes related to fibromyalgia. Due to lack of supply while being on a trip, intake of the drug was stopped abruptly, resulting in the development of classical abstinence‐like symptoms within 1 week. Abstinence‐like symptoms consisted of restlessness and insomnia for which the benzodiazepine lorazepam was given. Diarrhoea and abdominal cramps were treated with the peripherally active opioid loperamide, while bouts of cephalgia were treated with sumatriptan. Diffuse musculoskeltal‐related pain and restless leg syndrome (RLS) were treated with dextromethorphan. All these different medications proved to be efficacious as they resulted in the cessation of symptoms. Within 1 week symptoms ceased and the patient regained her normal activities without any sequelae. Although tramadol is considered a non‐habit‐ and non‐dependence‐forming analgesic, abstinence symptoms are likely to develop following abrupt cessation of intake, especially when the compound had been taken over 1 year. Therefore patients should be advised of such an effect whenever they decide to stop intake or their physician is planning to switch to another medication. To avoid abstinence‐like symptoms doses should be slowly tapered down.
Improving the quality of postoperative pain relief
Authors: Salomäki Timo E. , Hokajärvi Tuula M. , Ranta Pirjo , Alahuhta Seppo
Published: September 2002

A review of the literature shows a constant need to improve the quality of postoperative pain management. The objective of this study was to decrease the intensity and variation of postoperative pain by developing a nurse‐based pain service on the ward. An acute pain nurse was appointed and an educational programme with detailed algorithms was started. Regular pain intensity measurements were implemented. Postoperative pain intensity, treatments and side‐effects were assessed both before and after the introduction of the new system in 400 patients divided into two consecutive groups of equal size. The number of patients with inadequately treated pain (actual pain > 3/10) dropped by 64% after major gynaecological surgery (25 vs 9%, 95% CI for differences 7–24%;p< 0.001 for pain scores). On an average, inadequate pain relief (retrospective average pain > 3/10) on the first postoperative day was more frequent on the ward before than after the reform (47 vs 21%; 95% CI for differences 15–35%;p< 0.001 for pain scores). The incidence of side‐effects was similar in both groups (p> 0.05). The intensity and variation of postoperative pain on the ward decreased by developing a nurse‐based pain service with an acute pain nurse, an educational programme and regular pain intensity measurements.
The analgesic efficacy of topical capsaicin is enhanced by glyceryl trinitrate in painful osteoarthritis: a randomized, double blind, placebo controlled study
Authors: McCleane Gary
Published: September 2002

The aim of this study was to assess if the pain of osteoarthritis is reduced by topical capsaicin and to determine whether addition of glyceryl trinitrate has an effect on analgesic efficacy and tolerability of capsaicin. A randomized, double blind, placebo controlled study was carried out on 200 adult patients attending a Pain Clinic with osteoarthritis pain. Patients applied one of four creams topically over the affected joint over a 6 week period. Creams contained either placebo (vehicle), 0.025% capsaicin, 1.33% glyceryl trinitrate or 0.025% capsaicin + 1.33% glyceryl trinitrate. Analgesic efficacy, tolerability of cream and analgesic consumption were assessed. One hundred and sixty‐seven of 200 patients completed the study. Baseline visual analogue scores (0–10 scale) for pain were 6.40. There was a significant reduction in pain scores in the glyceryl trinitrate group (mean decrease 0.59, p< 0.05, 95% confidence limits 0.04–1.14), 0.025% capsaicin group (mean decrease 0.5, p< 0.05, 95% confidence limits 0.05–1.05) and the glyceryl trinitrate capsaicin group (mean decrease 1.1, p<0.05, 95% confidence limits 0.22–1.98). Baseline discomfort of application scores were similar for all but the capsaicin groups (they were significantly higher (by 2.1 units, p< 0.001)). The odds ratio in favour of continuing treatment was 2.1 (95% confidence limits 1.0–4.4) for glyceryl trinitrate and 2.4 (95% confidence limits 1.2–5.1) for capsaicin and 5.0 (95% confidence limits 3.8–6.4) for capsaicin GTN combination. The study showed that topical capsaicin and glyceryl trinitrate have an analgesic effect in painful osteoarthritis. When used together this effect is increased with the combination being more tolerable than capsaicin alone. Analgesic consumption is decreased by capsaicin, glyceryl trinitrate and to a greater extent by both combined.
Central pain in a hemispherectomized patient
Authors: Olausson Håkan , Marchand Serge , Bittar Richard G. , Bernier Jacques , Ptito Alain , Bushnell M.Catherine
Published: September 2002

We have examined a hemispherectomized patient who complained of touch‐evoked pricking and burning pain in her paretic hand, especially when the hand was cold. Psychophysical examination showed that for the paretic side she confused cool and warm temperatures, and confirmed that she had a robust allodynia to brush stroking that was enhanced at a cold ambient temperature. Functional magnetic resonance imaging (fMRI) showed that during brush‐evoked allodynia, brain structures implicated in normal pain processing (viz. posterior part of the anterior cingulate cortex, secondary somatosensory cortex, and prefrontal cortices) were activated. The fMRI findings thus indicate that the central pain in this patient was served by brain structures implicated in normal pain processing. Possible pathophysiological mechanisms include plasticity as well as thalamic disinhibition.
Reliability and sensitivity measures of the Greek version of the short form of the McGill Pain Questionnaire
Authors: Georgoudis George , Oldham Jacqueline A. , Watson Paul J.
Published: September 2002

The translation of existing healthcare measurement scales is considered a feasible, efficient and popular approach to produce internationally comparable measures. The short form of the McGill Pain Questionnaire is one of the most widely used and translated instruments to measure the pain experience. The Greek version of the short form of the McGill Pain Questionnaire (GR‐SFMPQ) has recently been developed and demonstrated satisfactory levels of internal consistency.

The objective of the present study was to assess the instrument';s reliability and sensitivity.

Eighty patients with spinal or knee pain were included. The test–retest reliability of the instrument was estim‐ated for measurements within the same day and after 15 days. The sensitivity of the measure was examined before and after the application of a physiotherapy therapeutic regime.

The correlation coefficients (Intraclass Correlation Coefficient and Spearman';s) ranged from 0.87–0.98 for within‐day measurements and from 0.70–0.92 for administrations between days. All indexes of the GR‐SFMPQ (total score, sensory and affective scores, total count of used words, visual analogue score, present pain index) managed consistently to detect the changes in pain experienced (p<0.05), after a therapeutic intervention, when assessing for the sensitivity of the questionnaire. An explorative discriminant analysis of the GR‐SFMPQ indexes managed to correctly classify up to 85% of the patients; a classification rate comparable to the full version MPQ rating capacity.

It can be argued from the results of this study that the Greek version of the SFMPQ fulfils the criteria of reliability and sensitivity to fluctuations of pain and can be utilized with confidence in cross‐cultural comparative research trials.