bluuebunny/crossref_metadata_2025 huggingface dataset:
Stable Mn‐magnetite derived from Mn‐siderite by heating in air
Authors: Isambert A. , Valet J.‐P. , Gloter A. , Guyot F.
Published: June 2003

Magnetic experiments, microscopic analyses and X‐ray diffractometry were conducted on oxidation products of Mn‐bearing natural crystalline siderite after successive heating steps in air. Magnetic measurements indicated the production of single‐domain and pseudo single domain ferrimagnetic phases with Curie temperatures between 420°C and 560°C. Hematite formation was detected by X‐ray diffraction after heating the siderite samples at 480°C, while Mn‐ferrite was formed at 500°C and persisted even after heating to 700°C. This final product is stable with a spinel structure and unit cell parameters intermediate between those of magnetite and maghemite. Transmission electron microscopy and electron energy loss spectroscopy analyses confirmed the presence of Mn in the spinel ferrite phase, which contains Fe(III), Mn(III), and Mn(II) ions. This phase appears as single crystals with euhedral shapes of average grain size 90–100 nm. In comparison to pure magnetite, the addition of Mn in the crystal lattice lowers the Curie temperature and explains the stability of the spinel phase. Thus stable magnetization carried by a magnetite related phase can be generated by oxidation of Mn‐siderite.
On the implementation of perfectly matched layers in a three‐dimensional fourth‐order velocity‐stress finite difference scheme
Authors: Marcinkovich Carey , Olsen Kim
Published: May 2003

Robust absorbing boundary conditions are central to the utility and advancement of 3‐D numerical wave propagation methods. It is in general preferred that an absorbing boundary method be capable of broadband absorption, be efficient in terms of memory and computation time, and be widely stable in connection with sophisticated numerical schemes. Here we discuss these issues for a promising absorbing boundary method, perfectly matched layers (PML), as implemented in the widely used fourth‐order accurate three‐dimensional (3‐D) staggered‐grid velocity‐stress finite difference (FD) scheme. Numerical results for point (explosive and double couple) and extended sources, velocity structures (homogeneous, 1‐D and 3‐D), and different thickness PML zones are excellent, in general, leaving no observable reflections in PML seismograms compared to the amplitudes of the primary phases. For both homogeneous half‐space and 1‐D models, typical amplitude reduction factors (with respect to the maximum trace amplitude) range between 1/100 and 1/625 for PML thicknesses of 5–20 nodes. A PML region of thickness 5 outperforms a simple exponential damping region of thickness 20 in a homogeneous half‐space model by a factor of 3. We find that PML is effective across the simulation bandwidth. For example, permanent offset artifacts due to particularly poor absorption of long‐period energy by the simple exponential damping are effectively absent when PML is used. The computational efficiency and storage requirements of PML, compared to the simple exponential damping, are reduced due to the need for only narrow absorbing regions. We also discuss stability and present the complete PML model for the 3‐D velocity‐stress system.
Improved description of sea level in the North Sea
Authors: Høyer Jacob L. , Andersen Ole B.
Published: May 2003

The scope of this paper is to merge in situ sea level observations with satellite altimetry observations to give a consistent view of the nontidal sea level fluctuations in the North Sea. The detided sea level variability is dominated by climate induced surges that propagate counterclockwise around the North Sea with speeds of ∼25 m/s and spatial scales of 100–1000 km. The individual sea level recorders agree very well with the satellite observations off the coast with correlation coefficients of 0.9. The sampling characteristics of the satellite and the in situ observations are used to construct a regression model. Regression of TOPEX/POSEIDON sea surface height data onto coastal sea level observations gives a mean hindcast skill of 0.7 and RMS errors of 8.2 cm for the North Sea. Validation of the model against independent ERS satellite crossover observations yields a mean RMS difference of 13 cm including the 4–7 cm noise in the satellite observations. The modeling of the true sea level is most likely better than 10 cm. The performance is presently better than the Danish storm surge model, suggesting that much can be gained by including the spatial information from the satellite observations in the models.
Mixing and geometry of advected, chemically reactive scalar fields: Application to chlorine deactivation over the midnorthern latitudes
Authors: Wonhas A. , Vassilicos J. C.
Published: June 2003

The mixing and reaction properties of advected chemicals are determined by the fractal dimension (or Kolmogorov capacity) D′ of a cut through the interface between the chemicals. We show that the amount m of reacted chemicals scales like where κ is diffusivity of the chemicals. If interscale transfer produced by the advecting flow has a linear time dependence, then the reaction rate of chemicals scales like with time t. Both relations are valid in a range of times and diffusivities where the diffusive length scales of the chemicals are within the range of scales where the interface between the chemicals has a well‐defined fractal dimension. We apply both relations to the problem of chlorine deactivation, ClO + NO2 → ClONO2, over the midnorthern latitudes. We determine numerically the Kolmogorov capacity of the interface between polar air which is comparatively rich in ClO and midlatitude air which is comparatively rich in NO2. Additionally, we show empirically that interscale transfer by the advecting flow can be well interpreted as having predominantly linear interscale transfer in the range of times under consideration. We can therefore explain diffusivity and time dependencies previously observed in numerical simulations. Furthermore we can extrapolate the results of such simulations down to realistically low diffusivities.
Bulk and size‐segregated aerosol composition observed during INDOEX 1999: Overview of meteorology and continental impacts
Authors: Ball W. P. , Dickerson R. R. , Doddridge B. G. , Stehr J. W. , Miller T. L. , Savoie D. L. , Carsey T. P.
Published: June 2003

Bulk and size‐segregated aerosol samples were collected from the NOAA R/V Ronald H. Brown as it cruised from Cape Town, South Africa, through the Indian Ocean and into the Bay of Bengal and Arabian Sea (February to April 1999; 33°S to 19°N). Throughout the Northern Hemisphere, aerosol loading was greater than in the Southern Hemisphere. Samples collected in air that had passed over India showed evidence of fossil fuel combustion, biomass burning, and eolian material, with elemental carbon (EC) dominating radiation absorption and the following relative contributions to the total mass of aerosol particles: ash 29%, nss‐sulfate 22%, sea salt 15%, nitrate 9%, organic material 8%, ammonium 6%, and EC 5%. Careful examination of the coarse mode revealed substantial concentrations of nitrate, adequate to acidify sea salt aerosols north of the Intertropical Convergence Zone. Air that had passed over Arabia showed little evidence of biomass burning but had more acidity, mineral dust, and higher nitrate to sulfate ratios than air from India. High concentrations of mineral dust played a major role in radiation absorption; mean contributions to aerosol mass in Arabian air were: ash 38%, nss‐sulfate 10%, sea salt 33%, nitrate 5%, organic material 4%, ammonium 1%, and EC 1%. From the ship we measured an average bulk aerosol concentration of 20 μg m−3 in the marine boundary layer of the northern Indian Ocean.
Recent climate changes in precipitable water in the global tropics as revealed in National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis
Authors: Zveryaev Igor I. , Chu Pao‐Shin
Published: May 2003

For the first time, long‐term climate changes in the atmospheric moisture over the global tropics are investigated using precipitable water (PW) from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data sets for two different periods: 1979–1998 and 1948–1998. Dominant modes of PW variability estimated for the shorter period (1979–1998) are in an overall agreement with those of satellite‐estimated precipitation in terms of both empirical orthogonal functions (EOF) spatial patterns and time‐dependent coefficients. Encouraged by this result, the entire time series of PW for the period of 1948–1998 is subsequently examined. Climatology of annual mean PW agrees well with the radiosonde‐based and satellite‐based climatologies of atmospheric moisture. EOF analysis applied to the entire time series indicates that the two leading modes explain 37.3% of the total variance of PW. The first EOF mode reflects that the trend‐like change is associated with evolutions in the observing systems of NCEP/NCAR reanalysis product. The second EOF has a spatial pattern, which is characterized by the zonal dipole structure. This mode is associated with the major climatic signal in the region, El Niño‐Southern Oscillation. Analysis of regional time series of annual mean PW has shown that, coincident with introduction of satellite data, step‐like changes in the mid to late 1970s are present over Malaysia, central tropical Pacific, and central Brazil. Abrupt changes of PW over North Africa are noticed in the late 1960s, and the large positive PW anomalies observed during the 1950s and 1960s are suspected to have quality deficiencies.
Simulating annual glacier flow with a linear reservoir model
Authors: Span Norbert , Kuhn Michael
Published: June 2003

In this paper we present a numerical simulation of the observation that most alpine glaciers have reached peak velocities in the early 1980s followed by nearly exponential decay of velocity in the subsequent decade. We propose that similarity exists between precipitation and associated runoff hydrograph in a river basin on one side and annual mean specific mass balance of the accumulation area of alpine glaciers and ensuing changes in ice flow on the other side. The similarity is expressed in terms of a linear reservoir with fluctuating input where the year to year change of ice velocity is governed by two terms, a fraction of the velocity of the previous year as a recession term and the mean specific balance of the accumulation area of the current year as a driving term. The coefficients of these terms directly relate to the timescale, the mass balance/altitude profile, and the geometric scale of the glacier. The model is well supported by observations in the upper part of the glacier where surface elevation stays constant to within ±5 m over a 30 year period. There is no temporal trend in the agreement between observed and modeled horizontal velocities and no difference between phases of acceleration and phases of deceleration, which means that the model is generally valid for a given altitude on a given glacier.
Aerosol hygroscopic properties as measured by lidar and comparison with in situ measurements
Authors: Feingold Graham , Morley Bruce
Published: June 2003

We demonstrate the ability of a single‐wavelength backscatter lidar to provide information on the uptake of water vapor by aerosol in a well‐mixed, cloud‐capped, boundary layer. Aerosol hydration has important consequences for the effect of aerosols on the Earth's radiation budget. A vertically pointing, airborne lidar is used to measure vertical profiles of aerosol backscatter beneath a stratocumulus cloud deck. In situ aircraft thermodynamic measurements are used to derive simultaneous profiles of relative humidity (RH) under the assumption that the boundary layer is well mixed. The change in backscatter is derived as a function of relative humidity over the range ∼85% RH to ∼98.5% RH. In situ measurements of the aerosol size distribution and composition are used to calculate the expected enhancement in backscatter due to equilibrium uptake of water vapor. Comparison between lidar backscatter enhancement as a function of RH and that derived from the in situ aerosol size distribution and composition measurements shows good agreement. Conditional sampling on strong updrafts/downdrafts indicates that aerosol backscatter tends to be higher in downdrafts than it is in updrafts for the same RH range. This is consistent with the concept of inertia of the larger hydrated particles to growth/evaporation at short timescales but may also be due to a bias in the way that lidar‐derived cloud base is interpreted in updrafts versus downdrafts. Calculations of enhancement in total scatter due to water vapor uptake with enhancement in backscatter suggest that the effects agree to within ∼20% of one another for RH < ∼95% but that they differ significantly for RH > 95%.
Issues concerning the sea emissivity modeling at L band for retrieving surface salinity
Authors: Dinnat Emmanuel P. , Boutin Jacqueline , Caudal Gérard , Etcheto Jacqueline
Published: May 2003

In order to prepare the sea surface salinity (SSS) retrieval in the frame of the Soil Moisture and Ocean Salinity (SMOS) mission we conduct sensitivity studies to quantify uncertainties on simulated brightness temperatures (Tb) related to uncertainties on sea surface and scattering modeling. Using a two‐scale sea surface emissivity model to simulate Tb at L band (1.4 GHz), we explore the influence on estimated SSS of the parameterization of the seawater permittivity, of the sea wave spectrum, of the choice of the two‐scale cutoff wavelength, and of adding swell to the wind sea. Differences between Tb estimated with various existing permittivity models are up to 1.5 K. Therefore a better knowledge of the seawater permittivity at L band is required. The influence of wind speed on Tb simulated with various parameterizations of the sea wave spectrum differs by up to a factor of two; for a wind speed of 7 m s−1 the differences on estimated SSS is several psu depending on the sea wave spectral model taken, so that sea spectrum is a major source of uncertainty in models. We find no noticeable effect on simulated Tb when changing the two‐scale cutoff wavelength and when adding swell to the wind sea for low to moderate incidence angles. The dependence of the wind‐induced Tb on SST and SSS being weak, we assess the error in SSS estimated assuming that the wind speed influence is independent of SST and SSS. We find errors on estimated SSS up to 0.5 psu for 20°C variation in SST. Therefore this assumption would induce regional biases when applied to global measurements.
Spatial and temporal monitoring of soil water content with an irrigated corn crop cover using surface electrical resistivity tomography
Authors: Michot Didier , Benderitter Yves , Dorigny Abel , Nicoullaud Bernard , King Dominique , Tabbagh Alain
Published: May 2003

A nondestructive and spatially integrated multielectrode method for measuring soil electrical resistivity was tested in the Beauce region of France during a period of corn crop irrigation to monitor soil water flow over time and in two‐dimensional (2‐D) with simultaneous measurements of soil moisture and thermal profiles. The results suggested the potential of surface electrical resistivity tomography (ERT) for improving soil science and agronomy studies. The method was able to produce a 2‐D delimitation of soil horizons as well as to monitor soil water movement. Soil drainage through water uptake by the roots, the progression of the infiltration front with preferential flow zones, and the drainage of the plowed horizon were well identified. At the studied stage of corn development (3 months) the soil zones where infiltration and drainage occurred were mainly located under the corn rows. The structural soil characteristics resulting from agricultural practices or the passage of agricultural equipment were also shown. Two‐dimensional sections of soil moisture content were calculated using ERT. The estimates were made by using independently established “in situ” calibration relationships between the moisture and electrical resistivity of typical soil horizons. The thermal soil profile was also considered in the modeling. The results showed a reliable linear relationship between the calculated and measured water contents in the crop horizon. The precision of the calculation of the specific soil water content, quantified by the root mean square error (RMSE), was 3.63% with a bias corresponding to an overestimation of 1.45%. The analysis and monitoring of the spatial variability of the soil moisture content with ERT represent two components of a significant tool for better management of soil water reserves and rational irrigation practices.
A model and observations of the multifractal spectrum of the heliospheric magnetic field strength fluctuations near 40 AU
Authors: Burlaga L. F. , Wang C. , Ness N. F.
Published: June 2003

The Voyager 1 (V1) observations of the magnetic field strength as a function of time during 1989, between 36.3 and 38.8 AU, have a multifractal structure in the range of scales from 2 to 32 days. We show that a 1‐D multi‐fluid MHD model with observations made at 1 AU during 1999 as input predicts the multifractal structure at 40 AU. The multifractal spectrum determined from the time series at 40 AU predicted by the model agrees with that observed by V1. The observed multifractal scaling symmetry can be explained by a deterministic model.
Satellite based retrieval of aerosol optical thickness: The effect of sun and satellite geometry
Authors: Chylek Petr , Henderson Brad , Mishchenko Michael
Published: June 2003

The DOE research satellite instrument, the Multispectral Thermal Imager (MTI), has several spectral bands in the visible and near infrared part of the spectrum that can be used for AOD (Aerosol Optical Depth) retrieval. Small pixel size (5 m × 5 m in the visible and 20 m × 20 m in the infrared) eliminates most sub‐pixel size cloud problems. We analyze 18 pairs of images, taken close to nadir and back along the track at a viewing angle around 60°, and compare results of a single view AOD retrieval algorithm with the AERONET measurements. We find that the single view AOD retrieval algorithm is more accurate at smaller scattering angles (at off‐nadir view). The root mean square (RMS) error of the MTI AOD single view retrieval in this region is around 0.03 compared to 0.11 for larger scattering angles at near‐nadir view.
Nonlinear acceleration of dispersive effects in field line resonances
Authors: Lu J. Y. , Rankin R. , Marchand R. , Tikhonchuk V. T.
Published: June 2003

Nonlinear dynamics of a dispersive field line resonance (FLR) is investigated in a dipolar magnetic geometry using a new finite element code TOPO. Time dependent dispersion and steepening of the perpendicular Alfvén velocity profile lead to the acceleration of dispersive effects and to localization of the FLR within an ionospheric density cavity. Consequently, shear Alfvén waves are trapped between turning points inside nonlinear density perturbations. This results in a complicated nonlinear FLR structure and an associated overlap of timescales for dispersion and nonlinearity. We show that nonlinear effects lead to fine scale structuring produced by the interplay of nonlinear and dispersive effects. We discuss the relevance of our results to observations of FLR's in the auroral zone.
Longest continuous ground‐based measurements of mesospheric CO
Authors: Forkman Peter , Eriksson Patrick , Winnberg Anders , Garcia Rolando R. , Kinnison Douglas
Published: May 2003

The longest continuous series of ground‐based measurements of mesospheric CO is presented. The continuous data cover the period September 2000 to September 2002. Sporadic measurements from 1988 and 1989 are also reported. The results show a large CO accumulation in the winter mesosphere, which is consistent with generally accepted ideas about the seasonally‐varying mean meridional circulation. Comparison of the observations with simulations by the Whole Atmosphere Community Climate Model (WACCM) indicate that the model can reproduce the observed seasonal cycle as well as much of its variability, although calculated columns amounts are smaller than the largest values seen in the data.
Viscous magnetization, archaeology and Bayesian statistics of small samples from Israel and England
Authors: Borradaile Graham J.
Published: May 2003

Certain limestones remagnetize viscously and noticeably over archaeological time‐intervals, after their reorientation into monuments. The laboratory demagnetization temperatures (TUB) for the VRM increase with the installation age; with rates of ∼0.07 C0/year for Israel chalk and ∼0.1C0/year for English chalk. The empirical relationship may be used to date enigmatic buildings or geomorphological features (e.g., land slips). Such correlations also give some insight into the viscous remagnetization process over time intervals τ ≤ 4000 years, which are unobtainable in laboratory studies. The TUB‐age relationship for the viscous remagnetization appears to follow a power law, linearized as log10(τ) ≈ b log10 (TUB). Different pelagic limestones follow different curves and, whereas conventional regression estimates the power law exponent b, the small sample size recommends a Bayesian statistical approach. From sites constructed with pelagic chalk from eastern England, precise prior information (b = 0.761) is compared with less precise information for much more ancient sites in northern Israel (b = 0.873). The collective posterior correlation shows a generalized power law exponent b = 0.849. That regression explains 84.9% of the collective variance in age (r2 = 0.849). Of course, site‐specific calibration is required for archaeological age determinations.
Diurnal effects in the composition of cirrus clouds
Authors: Sassen Kenneth , Liou Kuo‐Nan , Takano Yoshihide , Khvorostyanov Vitaly I.
Published: June 2003

Extended (7‐y) polarization lidar data, which are sensitive to ice crystal shape and orientation, are used to search for diurnal changes in cirrus clouds caused by solar heating. Average linear depolarization ratios are ∼0.02 lower during the day than night, minimizing at a 45° sun angle at ∼0.05 lower than the 0.350 nighttime average. Analysis of the diurnal pattern using scattering simulations suggests that plate crystals are more common during daylight, and that a feedback occurs between solar heating and the maintenance of horizontal plate orientations. This anisotropy also affects the cirrus solar albedo, representing an additional complication confronting climate modelers.
Deep equatorward propagation of inertial oscillations
Authors: Chiswell Stephen M.
Published: June 2003

Garrett [2001] points out that inertial oscillations can only propagate equatorwards. As they do so, they undergo steepening of their ray angles, and eventually the energy arrives at abyssal depths some distance equatorward of their origin. Here I show that with a given buoyancy frequency, there is a unique frequency for inertial waves that pass through any particular current meter location. Spectra from moorings off New Zealand show peaks at the predicted frequencies, and are presented in support of Garrett's theory.
Errors in high‐latitude SSTs and other geophysical products linked to NOAA‐14 AVHRR channel 4 problems
Authors: Podestá Guillermo P. , Arbelo Manuel , Evans Robert , Kilpatrick Katherine , Halliwell Vicki , Brown James
Published: June 2003

Errors in brightness temperatures for channel 4 in the Advanced Very High Resolution Radiometer (AVHRR) onboard the NOAA‐14 spacecraft are examined. The errors involve a low frequency of occurrence for some values, and a corresponding enhancement of frequency for others. Errors appear to be related to the conversion of analog to digital values. Unfortunately, it is not possible to identify and separate erroneous values. The most apparent errors in geophysical products derived from AVHRR's channel 4 occur at low brightness temperatures, therefore sea surface temperatures in high latitudes (below about 6°C) and cloud‐related products must be used with caution, as they may have systematic errors as large as 0.5°C.
Tree‐ring reconstructions of temperature and sea‐level pressure variability associated with the warm‐season Arctic Oscillation since AD 1650
Authors: D'Arrigo Rosanne D. , Cook Edward R. , Mann Michael E. , Jacoby Gordon C.
Published: June 2003

Arctic Oscillation (AO) changes are inferred from a tree‐ring reconstruction of a warm‐season temperature index. The reconstruction covers AD 1650–1975 and is based largely on chronologies from circumpolar‐Arctic and circum‐North Atlantic areas. It accounts for 48% of the variance in the instrumental AO record from 1900 to 1975, verifies using independent data, and exhibits its largest variance at low frequencies. Positive levels during 20th century periods equal or exceed values back to AD 1650. Trends (including lower values during ‘Little Ice Age’ periods) resemble those of Arctic temperature reconstructions, reflecting some data overlap, but also the strong link between the AO and northern temperatures. A reconstruction of an AO summer sea level pressure index shows similar trends. Comparison of these reconstructions with proxies of the North Atlantic Oscillation (NAO) and other indices can help clarify relationships between the AO and NAO, at least during the boreal warm season.
Vital effects in foraminifera do not compromise the use of δ11B as a paleo‐pH indicator: Evidence from modeling
Authors: Zeebe Richard E. , Wolf‐Gladrow Dieter A. , Bijma Jelle , Hönisch B.
Published: May 2003

The stable boron isotope composition (δ11B) of fossil foraminiferal shells is used as a paleo‐pH recorder and is therefore one of the most promising paleocarbonate chemistry proxies (“paleoacidimetry”). One crucial question regarding this proxy is whether foraminifera record the pH of the bulk seawater or the pH of the microenvironment (diffusive boundary layer, ∼500 μm), which is strongly influenced by life processes. Here we present a novel theoretical approach to address this question by using a diffusion‐reaction model. Model results indicate that the δ11B in planktonic foraminifera is primarily controlled by the pH of the microenvironment. We therefore predict that the δ11B of different species (e.g., symbiont‐bearing versus symbiont‐barren) or of foraminifera grown in the dark and in the light should be offset from the δ11B of inorganic calcite. This theoretical prediction was experimentally confirmed while this paper was written [Hönisch et al., 2003]. Most importantly, the model predicts that this offset is constant over a wide pH range. Thus the use of δ11B as a paleo‐pH indicator is not compromised through vital effects as modeled here.
Expression of the T‐cell markers CD2 and CD28 in healthy and atopic children during the first 18 months of life
Authors: Zdolsek Helena A. , Jenmalm Maria C.
Published: June 2003

Atopy may be associated with a reduced T‐cell function early in life, particularly regarding maturation of Th1 responses. The T‐cell surface molecules CD2 and CD28 are involved in important T‐cell activation pathways. Stimulation via the CD2 receptor increases the responsiveness to interleukin (IL)‐12, which is a potent inducer of Th1 responses, whereas CD28 stimulation is critical for Th2 differentiation. Our aim was to prospectively study the expression of the cell‐surface markers CD2 and CD28 on T‐cells in relation to development of atopic disease. Children (n = 172) were followed from birth to 18 months and the cumulative history of atopic disease was recorded. Blood samples were obtained at birth and at 18 months, and in a subgroup of 78 infants also at 3, 6 and 12 months. Flow cytometry was used to analyze the T‐cell markers CD2 and CD28, the latter also within the subsets of T‐helper (CD4+) and T‐cytotoxic (CD8+) cells. At 18 months, 31 children had and 118 did not have atopic symptoms. At this age, skin prick test (SPT) positive children with atopic symptoms with or without an atopic family history (AFH) showed a lower expression of CD2 mode fluorescence intensity (FI) as well as a lower proportion of CD2+ cells, as compared with non‐sensitized children with neither atopic symptoms nor AFH. This was accompanied by a higher expression of CD28 FI on CD2+CD8+CD28+ cells. No significant differences were seen at time points before 18 months, although the proportion of CD2+ tended to be low also earlier in life. In conclusion, the observed reduced expression of CD2 in atopic infants may support previous findings that atopy is associated with a reduced CD2 function. The high CD28 FI in SPT positive children with atopic symptoms may possibly be a consequence of a TH2‐skewed immune system.
Unconventional and conventional medicine: Who should learn from whom?
Authors: Niggemann Bodo , Grüber Christoph
Published: June 2003

Unconventional methods are increasingly used to treat allergic diseases. This article identifies various factors influencing physicians and patients in their choice of treatment and therapist. It is often difficult for patients and physicians to distinguish between the natural course of disease and the effects of medical intervention. The ‘placebo‐effect’ as well as other mechanisms may contribute to the therapeutic success. Chances and risks of unconventional methods are discussed. However, only by considering controlled studies can conventional and unconventional diagnostic and therapeutic methods be advocated on the basis of evidence rather than ideology.
Immunomodulation during sublingual therapy in allergic children
Authors: Ippoliti Flora , De Santis Wladimiro , Volterrani Anna , Lenti Luisa , Canitano Nicoletta , Lucarelli Sandra , Frediani Tullio
Published: June 2003

The clinical efficacy of sublingual immunotherapy (SLIT) has been demonstrated, but its mechanism of action is still controversial. The most recent experimental observations suggest that a critical role in the modulation of immune response is sustained by Th2 cytokines, such as interleukin‐4 (IL‐4), IL‐5 and IL‐13, by co‐stimulatory molecules, such as CD40 on B cells, and by hormones and neuropeptides. To better understand whether SLIT affects immune responses we used a double‐blind placebo‐controlled design. Eighty‐six children with mild asthma due to allergy to Dermatophagoides pteronyssinus (33 of whom also had rhinoconjunctivitis) were randomly assigned SLIT (n = 47) or placebo (n = 39). We assessed symptom scores using diary cards of each patient and determined the expression of CD40 on B cells and the serum concentration of ECP, IL‐13, prolactin (PRL) and ACTH at enrolment and after 6 months of therapy. We observed a significant reduction in asthma and rhinitis scores in the immunotherapy group compared with the placebo group, no variation in CD40 and ACTH, but a significant decrease in ECP, IL‐13 and PRL after 6 months of therapy (p <0.01). Our results confirm the efficacy and safety of SLIT, and lead us to believe that it could modulate the synthesis of Th2 cytokines, as revealed from the decrease of IL‐13. In addition, the reduction of PRL might be a signal of reduced activation of T lymphocytes.
T‐cell signal transduction in children with cow's milk allergy – increased MAP kinase activation in patients with acute symptoms of cow's milk allergy
Authors: Österlund Pamela , Von Willebrand Maria , Andersson Leif C. , Suomalainen Hanna
Published: June 2003

The precise immune mechanisms behind cow's milk allergy (CMA) are still unknown. Previously, the production of the cytokines TNF‐α and IFN‐γ in T cells from children with CMA has been shown to be decreased, and the production of IL‐4 has been shown to be increased when compared to healthy children. As these aberrations in cytokine production may be associated with disturbances in cellular function, we investigated whether T‐cell signal transduction is abnormal in children with CMA. For this purpose we evaluated the activation of the MAP kinase Erk2. Thirty‐nine infants were included in the study. Of those with CMA, 13 had acute symptoms and 9 were free of symptoms due to a successful elimination diet at the time of the study. To activate T cells and to stimulate MAP kinase phosphorylation, peripheral blood mononuclear cells (PBMC) were incubated with Concanavalin A (ConA). The change in MAP kinase phosphorylation was measured by Western blotting. The increase in MAP kinase phosphorylation after stimulation with ConA for 5 min was significantly higher in cells from patients with acute symptoms of CMA than in cells from CMA patients free of symptoms or cells from healthy children. A time‐course experiment showed that the change in MAP kinase phosphorylation was still increasing after 10 min incubation in cells from patients with acute symptoms of CMA. The increased MAP kinase activation was found to correlate positively with non‐IgE mediated CMA in patients with acute symptoms of CMA.
Medical treatment reverses cytokine pattern in allergic and nonallergic chronic rhinosinusitis in asthmatic children
Authors: Tosca Maria Angela , Cosentino Cristina , Pallestrini Eugenio , Riccio Anna Maria , Milanese Manlio , Canonica Giorgio Walter , Ciprandi Giorgio
Published: June 2003

A Th2 cytokine pattern has recently been reported both in allergic and nonallergic chronic rhinosinusitis in asthmatic children. The aim of the study was to evaluate the cytokine pattern in chronic rhinosinusitis in allergic and nonallergic asthmatic children before and after medical treatment. Thirty asthmatic children were evaluated, 18 males and 12 females (mean age 9.1 years). Sixteen were allergic and 14 were nonallergic. All children were asthmatic and suffered from chronic rhinosinusitis, whose diagnosis was confirmed by endoscopy. All of them were treated with amoxicilline‐clavulanate (20 mg/kg b.i.d.) and fluticasone propionate aqueous nasal spray (100 µg daily) for 14 days; a short course of oral corticosteroid was also prescribed (deflazacort 1 mg/kg daily for 2 days, 0.5 mg/kg daily for 4 days and 0.25 mg/kg daily for 4 days). Rhinosinusal lavage and nasal cytology were performed in all subjects before and after medical treatment. IL4 and IFNγ were measured by immunoassay and inflammatory cells were counted by conventional staining. Thirteen allergic children and 12 nonallergic children showed a negative endoscopy after the treatment. Allergic subjects showed a significant decrease of IL4 (p = 0.0002) and a significant increase of IFNγ (p = 0.03) after the treatment. Nonallergic children showed a significant decrease of IL4 (p = 0.0007) and a nonsignificant increase of IFNγ. A significant reduction of the inflammatory infiltrate was detected in all asthmatic children (p < 0.05). This study confirms a Th2 polarization in chronic rhinosinusitis both in allergic and nonallergic asthmatic children. Moreover, the medical treatment of chronic rhinosinusitis reversed the cytokine pattern from a Th2 towards a Th1 profile both in allergic and nonallergic children.
Lifetime prevalence of sexual abuse in a Swedish pregnant population
Authors: Stenson Kristina , Heimer Gun , Lundh Christina , Nordström Marie‐Louise , Saarinen Hilkka , Wenker Anita
Published: May 2003

Background.  Our primary purpose was to determine the prevalence of sexual abuse in a non‐selected pregnant population. We also endeavored to establish the age at which the abuse had occurred and the identity of the perpetrator and to analyze in sexually abused vis‐à‐vis non‐abused women, various socio‐economic and clinical variables.

Methods.  Over a period of 6 months, all women registered at antenatal clinics in Uppsala, Sweden, were questioned by their midwives regarding exposure to sexual abuse. Data from antenatal records were used to compare abused with non‐abused women concerning socio‐economic characteristics, previous ill health, reproductive history, pregnancy complications, and pregnancy outcome. Continuous variables were compared using the Student's t‐test or the Mann–Whitney U‐test and categorical variables using the chi‐square test or Fisher's exact test.

Results.  Of 1038 women assessed, 84 (8.1%) reported that at some time in their life they had been forced to participate in or subjected to sexual activity against their will. In most cases the perpetrator was someone the woman knew. When compared with non‐victims, those abused were more likely to report general health problems, especially gynecologic ill health and surgery, pulmonary disease/asthma, and/or psychiatric care. However, no differences were found regarding pregnancy outcome.

Conclusions.  It was found that one pregnant woman in 12 had reported sexual abuse at some time in their life. To midwives and obstetricians who work closely both physically and emotionally with pregnant women, an awareness of the extent of the problem and of possible sequelae is essential.
Deliveries, mothers and newborn infants in Sweden, 1973–2000
Authors: Odlind Viveca , Haglund Bengt , Pakkanen Milla , Olausson Petra Otterblad
Published: May 2003

Introduction.  The aim of this report is to present descriptive data from the Swedish Medical Birth Register (MBR) reflecting trends in obstetric and neonatal practices over three decades.

Material.  Since 1973 the MBR at the Swedish National Board of Health and Welfare receives information on all pregnancies in Sweden – around 95,000 annually – that have lead to delivery regarding the pregnancy, delivery and the newborn infant. In this study selected data from the MBR are presented as they have developed between 1973 and 2000.

Results.  There was a shift in age distribution of childbearing women towards older women. Cigarette smoking in early pregnancy decreased from 30% to 12%. In‐hospital time after both vaginal and cesarean (CS) delivery decreased and more than 50% of all women with a vaginal singleton delivery left hospital within 48 hours in 2000. The proportion of CS increased from 5 to 15% at singleton deliveries. The CS rate for breech deliveries increased and was nearly 80% in 2000. The mean birth weight increased, particularly the proportion of heavy infants. The proportion of early neonatal deaths decreased continuously, both for term infants and infants born after short gestational length, whereas no such downward trends was found for stillbirth during the last 10–15 years.

Conclusion.  Although several of the changes regarding pregnancy and delivery that occurred between 1973 and 2000 could be expected to influence pregnancy outcome negatively, the trends described here generally suggest improvement in maternal and child health.
Microinvasive squamous carcinoma of the cervix: treatment modalities
Authors: Mota Fernando
Published: May 2003

Patients with FIGO stage IA1 squamous cell carcinoma of the cervix can be treated conservatively with simple hysterectomy or, if young and desiring to preserve their fertility, with conization only, provided surgical margins are free of dysplasia or invasive disease. When the surgical margins are involved a repeat conization should be performed. Patients with FIGO stage IA2 or stage IA1 carcinoma with extensive lymph vascular space invasion benefit from a modified radical hysterectomy with pelvic lymph node dissection. If preservation of fertility is an issue, then conization with extraperitoneal or laparoscopic pelvic lymphadenectomy can be performed. Alternatively, radical trachelectomy with pelvic lymphadenectomy may be a safer procedure. Individualization of therapy based on an exhaustive pathological evaluation of an adequate cone biopsy specimen is of paramount importance for treatment planning and disease control.
Postpartum urinary incontinence
Authors: Hvidman Lone , Foldspang Anders , Mommsen SØren , Nielsen John Bugge
Published: May 2003

Background.  The aim of the present study was to identify prepregnancy, pregnancy and delivery correlates of urinary incontinence postpartum (PP UI) as reported by women in a cross‐sectional population sample.

Methods.  A questionnaire‐based cross‐sectional survey was carried out in 1998 in a random population sample of 3900 20‐ to 59‐year‐old women. The present study includes 376 women who had their last delivery during 1993–96.

Results.  UI immediately after childbirth and 6 months thereafter was reported by 23.4% and 2.7%, respectively. PP UI was strongly associated with UI both before and during the present pregnancy, explaining 37.5% and 51.7% of postpartum UI, respectively. Eight percent experienced their first UI episode ever immediately after the delivery. Among women undergoing a cesarean section 8.8% reported postpartum UI, as contrasted with 24.9% in other women. Postpartum UI was positively associated with perineal suturing but un‐associated with labor augmentation, episiotomy, birth weight, and breast‐feeding.

Conclusion.  In the present study, which included a comprehensive causal model, postpartum UI could be explained first of all as the decline of pregnancy UI, secondly as a manifestation of a pre‐existing tendency to react by UI, and finally as a consequence of the birth process itself.
Selective iron supplementation based on serum ferritin values early in pregnancy: are the Norwegian recommendations satisfactory?
Authors: Sandstad Berit , Borch‐Iohnsen Berit , Andersen Grete Maria , Dahl‐JØrgensen Birgit , FrØysa Ingrid , Leslie Cecilia , Hanneborg Aas Marianne , Eig TØrris Rolf , Sandem Svend Øyvind
Published: May 2003

Background.  The aims of the present study were to evaluate the recommendations by comparing compliance and adequacy of iron status at 6 weeks postpartum between one group given advice only and one group given advice plus iron supplement. In the latter group the efficacies of two iron preparations of different strengths and types were compared.

Methods.  Ninety‐three women had been given advice only (Group I) and were enrolled in the project at 6 weeks postpartum. Two hundred and thirty‐three women enrolled at their second antenatal visit and were given advice plus iron supplement; those with s‐ferritin <60 µg/L were randomized to a daily dose of 1) 60 mg Fe2+ (Ferromax®) or 2) 3.6 mg heme iron plus 24 mg Fe2+ (Hemofer®), and started taking the supplement at once if s‐ferritin <20 µg/L or at 20 weeks if 20–60 µg/L. In addition to hemoglobin as routine, s‐ferritin was measured in all the women at 6 weeks postpartum.

Results.  At 6 weeks postpartum median s‐ferritin was 28 and 34 µg/L in Groups I and II, respectively, and a significantly higher mean s‐ferritin (46.5 vs. 37.3 µg/L; p < 0.05) was found in women taking the highest dose. There were no correlations between s‐ferritin in early pregnancy and at 6 weeks postpartum. Peripartum blood loss was the main indicator for iron status at 6 weeks postpartum.

Conclusion.  Iron supplementation based on iron status early in pregnancy, with 60 mg ferrous iron or 27 mg iron containing heme, resulted in adequate iron stores at 6 weeks postpartum among 75% or 70% of the women, respectively. However, 6 weeks were not sufficient to rebuild iron stores in women with large peripartum blood loss.
Prostaglandin: cervical ripening in hypertensive pregnancies
Authors: Ferrazzani Sergio , De Santis Lidia , Carducci Brigida , Caliandro Dario , De Carolis Sara , Di Simone Nicoletta , Caruso Alessandro
Published: May 2003

Background.  To determine the outcome of cervical ripening with intracervical prostaglandin E2 (PEG2) in hypertensive and non‐hypertensive high‐risk pregnancies in terms of successful ripening, mode of delivery, time intercorring between ripening and the beginning of labor or parturition and, at least, duration of labor.

Methods.  A total of 63 women with a diagnosis of hypertensive disorders were included in the study protocol. These 63 women were compared with 71 consecutive high‐risk pregnancies requiring induction of labor for maternal and/or fetal indications. Cervical ripening was performed with single or multiple doses of 0.5 mg of intracervical PGE2 gel.

Results.  The rate of successful ripening was 84% for non‐hypertensive patients (60/71) and 69% (43/63) for hypertensive patients ( p < 0.03). Twenty‐four out of 63 hypertensive patients (38%) and 21 out of 71 non‐hypertensive patients (30%) ( p < 0.05) were delivered by cesarean section. After stratification of hypertensive patients, the time interval from the first PGE2 administration to the onset of labor or vaginal delivery was significantly longer for preeclamptic patients vs. non‐hypertensive patients or non‐preeclamptic hypertensive patients. There were no differences in the duration of labor.

Conclusions.  Among hypertensive patients, only preeclamptic patients showed a lower rate of successful ripening and vaginal delivery if compared with non‐preeclamptic or non‐hypertensive patients; however, a vaginal delivery might be obtained in most preeclamptic patients when suitable cervical ripening was performed in the presence of clinician‐perceived urgency to delivery.
Activin B in patients with granulosa cell tumors: serum levels in comparison to inhibin
Authors: Vihko Kimmo K. , Bläuer Merja , Puistola Ulla , Tuohimaa Pentti
Published: May 2003

Background.  Activins and inhibins are polypeptide hormones/growth factors of primarily gonadal origin. In the ovary, activins and inhibins are primarily synthesized by granulosa cells. Serum inhibin measurements have been used for the follow‐up of patients with granulosa‐cell tumors (GCT) after surgery.

Methods.  We have employed a recently developed assay to study whether activin B (A) measurements can be used as a marker of progression of GCTs. Additionally, these measurements have been compared with simultaneously run inhibin measurements using a commercial assay. Serum samples of three patients suffering from GCTs (all stage Ia) were collected at primary surgery and at controls thereafter.

Results.  In patient AM, serum inhibin levels have remained elevated while A levels are low; there has been no evidence of a residual tumor. In patient AR, there has been no clinical evidence of a residual tumor, and both serum A and inhibin levels have remained low. In patient PP, a residual tumor was found 6 years after primary surgery; at the time A levels were elevated, while inhibin levels remained low.

Conclusion.  We introduce A as a promising new marker for postoperative follow‐up of patients suffering from GCTs.
Early and late half‐life of human chorionic gonadotropin as a predictor of persistent trophoblast after laparoscopic conservative surgery for tubal pregnancy
Authors: Billieux Marie‐Hélène , Petignat Patrick , Anguenot Jean‐Luc , Campana Aldo , Bischof Paul
Published: May 2003

Background.  To determine if the early or late half‐lives (T0.5) of human chorionic gonadotropin (hCG) can identify patients with persistent trophoblastic activity after conservative surgery for tubal pregnancy.

Design.  Prospective cohort study.

Setting.  Department of obstetrics and gynecology of a university hospital.

Methods.  All patients with a tubal pregnancy treated by laparoscopic salpingostomy between June 1997 and September 2000 were enrolled in the study. Postoperative sequential hCG sampling was performed at days 0, 2 (± 1) and 7 (± 2) and followed until levels were undetectable. Taking the biexponential hCG declining curve as a model, we calculated the early (days 0–2) and late (days 2–7) T0.5 hCG values.

Main outcome measure.  To assess success or failure of surgical treatment.

Results.  Seventy‐three patients with an ectopic pregnancy were managed by conservative surgery. Early and late T0.5 allowed us to identify 2/10 and 9/10 women, respectively, with persistent trophoblast. Late T0.5 levels revealed two patients with false‐positive values, but one patient showed a secondary increase in hCG after day 7 (false‐negative) despite a normal late T0.5.

Conclusions.  Early and late half‐lives of hCG do not identify all women at risk for persistent ectopic pregnancy. To exclude persistent trophoblast, postoperative serum hCG determination should be performed until levels are undetectable.