bluuebunny/crossref_metadata_2025 huggingface dataset:
Congenital heart disease and aneuploidy
Authors: Wimalasundera R. C. , Gardiner H. M.
Published: December 2004

Congenital heart disease (CHD) is one of the commonest prenatal diagnoses made on routine ultrasound screening. Overall, up to 33% of CHD are associated with fetal aneuploidy. However, some specific cardiac lesions have a significantly greater association with particular chromosomal abnormalities. The majority of fetuses with CHD and aneuploidy also have extra‐cardiac anomalies and are best managed by a multidisciplinary team where the management and prognosis of the cardiac defect can be discussed in the context of the baby as a whole. It is therefore important for clinicians involved in the management of fetuses with CHD to be aware of the association of aneuploidy as well as the prognosis and management of these cases, so that they can appropriately counsel the parents. In this chapter, we review the frequency and types of aneuploidy associated with the commonly diagnosed CHD and discuss their management. Copyright © 2004 John Wiley & Sons, Ltd.
Natural history and outcome of prenatally diagnosed cystic hygroma
Authors: Ganapathy R. , Guven M. , Sethna F. , Vivekananda U. , Thilaganathan B.
Published: December 2004

Objective

To define the outcome in cases of cystic hygroma diagnosed from a routine obstetric population.

Method

This was a retrospective study of 42 cases of fetal cystic hygroma detected at 11 to 23 weeks' gestation in a routine obstetric population of 25 352 pregnancies. Fetal cystic hygroma was categorized according to position, severity, presence of cardiac defects and Hydrops fetalis.

Results

There were 20 (47.6%) cases with aneuploidy (9 trisomies and 11 Turner's syndrome). Major congenital cardiac defects were identified in 12 (28.6%) cases. Regression of the hygroma was noted in 2/20 (10%) of the aneuploid pregnancies and 3/17 (17.6%) of the euploid pregnancies. The majority (90.0%) of the aneuploid fetuses were female. In contrast, 70.58% of the fetuses in the euploid group were male and all the surviving normal babies were also male (n = 3).

Conclusion

The findings of this study would support invasive prenatal diagnosis for an ultrasound finding of fetal cystic hygroma. Even in euploid pregnancies with cystic hygroma, there is a high mortality with associated abnormalities. The data also suggest a guarded pregnancy prognosis for the finding of fetal cystic hygroma, and that it is improved with spontaneous resolution, especially in male fetuses of normal karyotype. Copyright © 2004 John Wiley & Sons, Ltd.
Indentation induced mechanical and electrical response in ferroelectric crystal investigated by acoustic mode AFM
Authors: Yu H. F. , Zeng H. R. , Ma X. D. , Chu R. Q. , Li G. R. , Luo H. S. , Yin Q. R.
Published: December 2004

The mechanical and electrical response of Pb (Mg1/3Nb2/3)‐
O3–PbTiO3 single crystals to micro‐indentation are investigated using the newly developed low frequency scanning probe acoustic microscopy which is based on the atomic force microscope. There are three ways to release the stress produced by indentation. Plastic deformation emerged directly underneath the indentor and along the indentation diagonals. In addition, indentation‐induced micro‐cracks and new non‐180° domain structures which are perpendicular to each other are also observed in the indented surface. Based on the experimental results, the relationship between the cracks and the domain patterns was discussed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Scalability evaluation of theYimastreaming media architecture
Authors: Zimmermann Roger , Shahabi Cyrus , Fu Kun , Yao Shu‐Yuen Didi
Published: December 2004

Over the last decade research has been pursued on all aspects of streaming media. While many theoretical results have been reported in the literature, few performance results of large‐scale systems have been published. In this report we specifically explore the scalability aspects of our Yima streaming media architecture in an end‐to‐end test environment. With Yima, it was our goal to design and implement an architecture that would scale in performance from small to large systems. Some of the design features include (1) a multi‐node cluster architecture based on commodity hardware and custom software, (2) media type independence (support ranges from 500 Kb s$^{-1}$MPEG‐4 to 45 Mb s$^{-1}$HDTV, at both variable and constant bitrates), (3) fine‐grained online scale up/down capabilities, and (4) a client‐controlled rate smoothing protocol. We briefly discuss the design and implementation of these capabilities of Yima and then thoroughly evaluate its scalability through several sets of experiments. Our results show that Yima scales linearly (within the range of our test parameters) as a function of the cluster size and also as a function of available resources such as network bandwidth and CPU performance. Copyright © 2004 John Wiley & Sons, Ltd.
Multiple query optimization in middleware using query teamwork
Authors: O'Gorman K. , El Abbadi A. , Agrawal D.
Published: December 2004

Multiple concurrent queries occur in many database settings. This paper describes the use of middleware as an optimization tool for such queries. Since common subexpressions derive from common data and the data is usually greatest at the source, the middleware exploits the presence of sharable access patterns to underlying data, especially scans of large portions of tables or indexes, in environments where query queuing or batching is an acceptable approach. The results show that simultaneous queries with such sharable accesses have a tendency to form synchronous groups (teams) which benefit each other through the operation of the disk cache, in effect using it as an implicit pipeline. The middleware exploits this tendency by queuing and scheduling the queries to promote this interaction, using an algorithm designed to promote such teamwork. This is implemented as middleware for use with a commercial database engine. The results include tests using the query mix from the TPC Benchmark™ R, achieving a speed‐up of 2.34 over the default scheduling provided by one database. Other results show that the success depends on the details of the computing environment. Copyright © 2004 John Wiley & Sons, Ltd.
Uncertainties in sea surface temperature retrievals from space: Comparison of microwave and infrared observations from TRMM
Authors: Ricciardulli Lucrezia , Wentz Frank J.
Published: December 2004

A study of the uncertainties in infrared (IR) and microwave (MW) sea surface temperature (SST) retrievals by satellite is described here. The availability of both infrared (VIRS) and microwave (TMI) sensors on the Tropical Rainfall Measurement Mission (TRMM) provided an opportunity to perform this detailed SST intercomparison from two distinct but colocated sensors. Infrared retrievals provide good spatial resolution, but they are limited to clear‐sky conditions. Microwave observations provide supplemental SST information in cloudy areas, but they are subject to other limitations such as poor spatial resolution and possible wind biases. One year of colocated VIRS and TMI SSTs are analyzed here, together with other colocated ancillary data sets including surface winds and water vapor, and potential sources of error are presented. The analysis shows some residual IR SST's dependence on atmospheric water vapor, despite corrective terms in the algorithm, with biases of a few tenths of a degree. The inclusion of a water vapor term in the IR algorithm reduces these biases. The results also show a higher uncertainty in MW SST retrievals for winds greater than 12 m/s, and a warm bias of MW SSTs of the order of 1°C within 50–100 km from land. Other potential sources of uncertainties discussed in the paper are undetected clouds, choice of IR SST algorithm, diurnal warming of the skin layer, and satellite maneuvers. The results of this intercomparison are valuable for the development of a future generation of a blended IR/MW SST data set, which combines the strengths of each observational method.
Evaluation of soil CO2 production and transport in Duke Forest using a process‐based modeling approach
Authors: Hui Dafeng , Luo Yiqi
Published: December 2004

Soil surface CO2 efflux is an important component of the carbon cycle in terrestrial ecosystems. However, our understanding of mechanistic controls of soil CO2 production and transport is greatly limited. A multilayer process‐based soil CO2 efflux model (PATCIS) was used to evaluate soil CO2 production and transport in the Duke Forest. CO2 production in the soil is the sum of root respiration and soil microbial respiration, and CO2 transport in the soil mainly simulates gaseous diffusion. Simulated soil CO2 efflux in the Duke Forest ranged from 5 g CO2 m−2 d−1 in the winter to 25 g CO2 m−2 d−1 in summer. Annual soil CO2 efflux was 997 and 1211 g C m−2 yr−1 in 1997 and 1998, respectively. These simulations were consistent with the observed soil CO2 efflux. Simulated root respiration contributed 53% to total soil respiration. Soil temperature had the dominant influence on soil CO2 production and CO2 efflux while soil moisture only regulated soil CO2 efflux in the summer when soil moisture was very low. Soil CO2 efflux was sensitive to the specific fine root respiratory rate and live fine root biomass. Elevated CO2 increased annual soil CO2 efflux by 26% in 1997 and 18% in 1998, due mainly to the enhanced live fine root biomass and litterfall. On a daily to yearly basis, CO2 production is almost identical to CO2 efflux, suggesting that CO2 transport is not a critical process regulating daily and long‐term soil surface CO2 effluxes in the Duke Forest. We also developed a statistical model of soil CO2 efflux with soil temperature and moisture. Daily soil CO2 efflux estimation by the statistical model showed a similar pattern to the simulated soil CO2 efflux, but the total annual CO2 efflux was slightly lower. While the statistical model is simple, yet powerful, in simulating seasonal dynamics of soil CO2 efflux, the process‐based model has the potential to advance our mechanistic understanding of soil CO2 efflux variations in the current and future worlds.
Influence of the Pacific Decadal Oscillation on hydrochemistry of the Rio Grande, USA, and Mexico
Authors: Yuan Fasong , Miyamoto Seiichi
Published: December 2004

The hydrochemistry has been examined using the major element composition of river water at 12 gauging stations along the Rio Grande. As the Rio Grande Basin consists of two watersheds that have different hydrologic and climatic regimes, two chloride concentration records from the El Paso and Falcon Dam gauging stations have been extracted to reflect long‐term variability in river chemistry of the upper and lower basins over the last 50–70 years. Both records contain decadal variability in chloride concentration but are different in nature. The chloride concentration record from the upper basin displays a distinct pattern of decadal variability similar to the Pacific Decadal Oscillation (PDO). This indicates the chloride concentration at El Paso is largely determined by the amount of stream discharge of the upper basin that is associated with the PDO. Conversely, there is no such pattern of decadal variability in the chloride concentration record from the lower basin though several of the chloride concentration maxima coincide with minima in the PDO index. Instead, the chloride concentration record from the lower basin contains a progressively increasing trend of chloride concentration from 1970 to 1990, suggesting that anthropogenic disturbances (e.g., dam constructions and increased irrigation demands) may also play a role in intervening long‐term changes in river chemistry.
Cluster observations of velocity space‐restricted ion distributions near the plasma sheet
Authors: Wilber M. , Lee E. , Parks G. K. , Meziane K. , Carlson C. W. , McFadden J. P. , Rème H. , Dandouras I. , Sauvaud J.‐A. , Bosqued J.‐M. , Kistler L. , Möbius E. , McCarthy M. , Korth A. , Klecker B. , Bavassano‐Cattaneo M.‐B. , Lundin R. , Lucek E.
Published: December 2004

We present Cluster ion observations obtained at 18 RE in the magnetotail on 1 October 2001. According to a recent analysis, the quartet encountered a reconnection region and a tailward‐moving neutral line. We examine in detail selected 3‐D ion distributions, which through much of the hour following 0925 UT were non‐gyrotropic. B‐perpendicular slices of velocity space showed crescent‐shaped regions. Occupied gyrophases were consistent over a wide range of parallel velocities, stable over time, and occurred unaccompanied by strong ion gyrofrequency waves. We interpret these observations as signatures of remote sensing near sharp particle gradients. In this view, distributions obtained simultaneously while Cluster straddled the current sheet are simply explained. Additionally, the computed first moments can have large transverse ( × B) components (, a unit boundary normal), without net plasma transport. We infer separate O+ layers above and below the current sheet.
Sensitivity to wave breaking and the Prandtl number in the ocean mixed layer model and its dependence on latitude
Authors: Noh Yign
Published: December 2004

Investigation of the sensitivity to wave breaking and the Prandtl number in the ocean mixed layer model under surface heating reveals an interesting latitude‐dependent feature in the dynamical process of the ocean mixed layer. The effect of Prandtl number variation with stratification plays an important role in the equatorial ocean, whereas, in the extratropical ocean, the effect of strong near‐surface turbulence caused by wave breaking is dominant. The contrasting responses to parameterization is attributed to the fact that turbulence production in the ocean mixed layer is dominated by turbulent kinetic energy flux from the sea surface in the extratropical ocean, and by shear production in the equatorial ocean. Comparisons were also made between the sensitivity tests from different ocean mixed layer models.
Fine‐scale seismic structure of the shallow volcanic crust on the East Pacific Rise at 9°50′N
Authors: Sohn Robert A. , Webb Spahr C. , Hildebrand John A.
Published: December 2004

We use a combination of body wave and interface wave observations from an on‐bottom seismic refraction survey to constrain the fine‐scale seismic structure of the upper crust in a ∼3 × 3 km field area centered on the East Pacific Rise at 9°50′N. We detonated 18 explosive shots (18 sources) in a circular pattern (1.5 km radius) on the rise axis and recorded seismic arrivals with eight ocean bottom seismometers (eight receivers). We observed 30–40 Hz compressional body waves from all shots (144 P waves) and 1–3 Hz Stoneley (interface) waves on a subset of source‐receiver pairs (58 interface waves). Using a station correction inversion, we find that roughly half of the variance in the P wave first‐arrival times results from lateral variations in the thickness of the surface low‐velocity layer (SLVL), a layer of extremely porous lava and basalt breccia with an average P wave velocity of 2.2 km s−1. The SLVL thickness increases from <20 m along the axial summit trough (AST) to ∼120 m at near‐axis lava depocenters, which are not symmetric about the rise axis. Depocenters are located ∼0.5 km to the west and ∼1.5 km to the east of the rise axis. Tomographic inversion of the Stoneley wave first arrivals reveals that shear velocities in the SLVL covary with the layer thickness, exhibiting a similar asymmetric pattern, with shear velocities increasing from ∼320 m s−1 near the AST to ∼520 m s−1 at the near‐axis depocenters. Our analysis demonstrates that the seismic characteristics of the extrusive layer near the rise axis are related primarily to volcanic features and processes. The thickness and velocity of the SLVL are low on the axis and within channel networks that deliver lava flows away from the axis and then increase rapidly at the distal ends of the channels where the lavas are deposited. We find that azimuthal anisotropy exerts only a weak influence on our P wave first‐arrival times, which we model as weak (4%) seismic azimuthal anisotropy in the upper dikes with a fast axis oriented N23°–32°W. We find no evidence for seismic azimuthal anisotropy in the extrusive layer.
Seismicity gaps and the shape of the seismic zone in the Banda Sea region from relocated hypocenters
Authors: Das S.
Published: December 2004

We relocate hypocenters for more than 800 earthquakes deeper than 50 km with mb ≳ 5.0, along the Banda arc, using several thousand handpicked direct, depth, and core‐reflected phases, in addition to phases reported by the International Seismological Centre. The seismicity distribution is found to be very nonuniform both along the arc and in depth. Gaps in the relocated hypocenters exist along depth in most places of the arc, with the upper edge of the gaps varying from 100 to 450 km depth and the lower edge varying from 350 to 670 km in different portions of the arc. The seismic zone between 129 and 131°E in the 100–200 km depth range is the widest along the arc both in strike and downdip. This region, near the highest arc curvature, has the highest seismic activity and is the only part of the arc with earthquakes continuously occurring from the surface down to below 600 km. The very deep earthquakes under Sulawesi are shown to be part of the west‐southwest dipping Seram slab. In the westernmost part of the Banda arc the slab is under downdip tension in the 50–250 km depth range, while the deepest portion of the slab in this region is under compression. From 128 to 131°E the slab between 100 and 200 km depth is under mainly horizontal compression. Our study supports the “two‐slab” model for the Banda arc. The depth of the Wadati‐Benioff zone below the volcanoes is ∼60–100 km for the five volcanoes between 128 and 130°E and ∼150 km for the 23 volcanoes between 118 and 124°E.
The 20‐s Rayleigh wave attenuation tomography for central and southeastern Asia
Authors: Yang Xiaoning , Taylor Steven R. , Patton Howard J.
Published: December 2004

We conducted a tomographic inversion of 20‐s Rayleigh wave spectral amplitudes to obtain a two‐dimensional (2‐D) attenuation model for central and southeastern Asia. We designed an amplitude‐measuring procedure, making use of the phase match filtering technique and available source and path information, to minimize the measurement error. The resulting amplitude measurements showed much reduced scatter with consistent average attenuation estimates. The average quality factor Q from the measurements is about 220, lower than most global estimates. We took a two‐step approach in our tomographic inversion. We first inverted the two‐station amplitude ratios for a coarse‐grid attenuation model. We then used this model as the a priori model and inverted the single‐station spectral amplitudes to obtain the final attenuation model along with source and site response terms. The attenuation model from the inversion has a broad correlation with the geology and tectonics of the region. Low attenuation is seen in stable cratonic regions. High attenuation correlates with tectonically active regions. Compared with 1‐D distance corrections, the use of 2‐D attenuation model for path correction in Ms calculations reduced the station magnitude scatter by 16–18% on the average.
Coastal upwelling process on a continental shelf limited by submarine canyons, Concepción, central Chile
Authors: Sobarzo Marcus , Djurfeldt Leif
Published: December 2004

The subinertial flow on the continental shelf off Concepción (central Chile) and its relation with the local wind‐forcing and the topography are studied. Emphasis is placed on the three‐dimensional aspects and the effect of the topography on the classical two‐dimensional approach to the coastal upwelling. Time series coming from 18 current meters installed on six moorings during March–April 1994 were analyzed. Hydrographic data were collected during two hydrographic cruises (6–7 March and 30–31 March). Complementary information includes wind data and sea level. Empirical orthogonal functions using all series showed two principal subinertial flow patterns. The first mode corresponds to an alongshore flow responding to the intensification of southwesterly wind on a 3‐ to 10‐day scale. The second mode is dominated by the cross‐shore fluctuations at the shelf break. The importance of the local wind‐forcing appears clearly when comparing the theoretical and observed Ekman transport in the north and central shelf (R = 0.8). Near the bottom a mean southward flow was found with a clear southward intensification induced by the bathymetry and probably by a meridional pressure gradient. This bottom flow modifies the typical coastal upwelling pattern through an offshore Ekman transport in the surface and bottom layers. This implies that the compensation flow for the coastal divergence comes from intermediate waters that arrive onto the shelf through ageostrophic process related with the submarine canyons located toward the north and south of the shelf.
Mesoscale variability from a high‐resolution model and from altimeter data in the North Atlantic Ocean
Authors: Brachet S. , Le Traon P. Y. , Le Provost C.
Published: December 2004

The objective of the paper is to analyze the degree of realism of the Parallel Ocean Program (POP) model of the Los Alamos Laboratory using the combined TOPEX/Poseidon and ERS‐1/2 (TPERS) sea level anomaly (SLA) data sets and to present a detailed study of mesoscale characteristics in the North Atlantic. This description spans 8 years of data from 1993 to 2000. At first, we focus on the analysis of the mean eddy kinetic energy (EKE) and show that the major characteristics of mesoscale variability are realistically simulated despite an overestimation of the EKE model in the Gulf Stream region. We then describe the SLA space and timescales and propagation velocities at a resolution never achieved before. There is a high level of agreement between the model and altimeter values regarding spatial scales and propagation velocities. POP timescales are, however, significantly longer in the subtropical regions. The westward zonal propagation velocity of both the model and the observations are higher than the speed computed from standard Rossby wave theory. The effect of mean current advection on POP and TPERS propagation velocities is also clearly seen in the Labrador Current and in the Gulf Stream and its recirculations. Finally, a study of the seasonal and interannual variability of the high‐frequency (HF) EKE is carried out. The model reproduces accurately most of the HF‐EKE seasonal variations in the Caribbean Sea and at high latitudes despite a phase advance. A clear HF‐EKE interannual variability is then evidenced. Our hypothesis is that a contraction of the subpolar and subtropical gyres due to the North Atlantic Oscillation (NAO) could explain a reduction of the eddy activity in the North Atlantic Current, in the Newfoundland basin, and in the Azores Current. In the Caribbean Sea, the interannual variability of the EKE for both POP and TPERS seems to be caused by an interannual variability of the wind stress.
Pole‐to‐pole validation of Envisat GOMOS ozone profiles using data from ground‐based and balloon sonde measurements
Authors: Meijer Y. J. , Swart D. P. J. , Allaart M. , Andersen S. B. , Bodeker G. , Boyd I. , Braathen G. , Calisesi Y. , Claude H. , Dorokhov V. , von der Gathen P. , Gil M. , Godin‐Beekmann S. , Goutail F. , Hansen G. , Karpetchko A. , Keckhut P. , Kelder H. M. , Koelemeijer R. , Kois B. , Koopman R. M. , Kopp G. , Lambert J.‐C. , Leblanc T. , McDermid I. S. , Pal S. , Schets H. , Stubi R. , Suortti T. , Visconti G. , Yela M.
Published: December 2004

In March 2002 the European Space Agency (ESA) launched the polar‐orbiting environmental satellite Envisat. One of its nine instruments is the Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument, which is a medium‐resolution stellar occultation spectrometer measuring vertical profiles of ozone. In the first year after launch a large group of scientists performed additional measurements and validation activities to assess the quality of Envisat observations. In this paper, we present validation results of GOMOS ozone profiles from comparisons to microwave radiometer, balloon ozonesonde, and lidar measurements worldwide. Thirty‐one instruments/launch sites at twenty‐five stations ranging from the Arctic to the Antarctic joined in this activity. We identified 6747 collocated observations that were performed within an 800‐km radius and a maximum 20‐hour time difference of a satellite observation, for the period between 1 July 2002 and 1 April 2003. The GOMOS data analyzed here have been generated with a prototype processor that corresponds to version 4.02 of the operational GOMOS processor. The GOMOS data initially contained many obviously unrealistic values, most of which were successfully removed by imposing data quality criteria. Analyzing the effect of these criteria indicated, among other things, that for some specific stars, only less than 10% of their occultations yield an acceptable profile. The total number of useful collocated observations was reduced to 2502 because of GOMOS data unavailability, the imposed data quality criteria, and lack of altitude overlap. These collocated profiles were compared, and the results were analyzed for possible dependencies on several geophysical (e.g., latitude) and GOMOS observational (e.g., star characteristics) parameters. We find that GOMOS data quality is strongly dependent on the illumination of the limb through which the star is observed. Data measured under bright limb conditions, and to a certain extent also in twilight limb, should be used with caution, as their usability is doubtful. In dark limb the GOMOS data agree very well with the correlative data, and between 14‐ and 64‐km altitude their differences only show a small (2.5–7.5%) insignificant negative bias with a standard deviation of 11–16% (19–63 km). This conclusion was demonstrated to be independent of the star temperature and magnitude and the latitudinal region of the GOMOS observation, with the exception of a slightly larger bias in the polar regions at altitudes between 35 and 45 km.
Feedback upon dust emission by dust radiative forcing through the planetary boundary layer
Authors: Miller R. L. , Perlwitz J. , Tegen I.
Published: December 2004

Large changes to the amount of airborne soil particles (or “mineral dust” aerosol) inferred from the climate record raise the question of whether radiative forcing by dust particles amplifies or else diminishes these changes. A previous study with an atmospheric general circulation model (AGCM) indicates that dust radiative forcing in the present‐day climate reduces emission of dust into the atmosphere. Here, we interpret this reduction as an interaction between dust radiative forcing and the planetary boundary layer (PBL). By reducing sunlight incident upon the surface, dust decreases the turbulent flux of sensible heat into the atmosphere. This reduces turbulent mixing within the PBL, along with the downward transport of momentum to the surface, resulting in a decrease of surface wind speed and dust emission. We illustrate this mechanism by comparing the diurnal cycle of emission simulated by two versions of an AGCM, one containing dust radiative forcing, and the other with this forcing set to zero. At some of the most productive source regions, morning emission is reduced in proportion to the surface radiative forcing. We suggest that this negative feedback is underestimated by the AGCM.
Calibration of multisatellite observations for climatic studies: Microwave Sounding Unit (MSU)
Authors: Grody Norman C. , Vinnikov Konstantin Y. , Goldberg Mitchell D. , Sullivan Jerry T. , Tarpley J. Dan
Published: December 2004

The Microwave Sounding Units (MSU) aboard the NOAA series of polar orbiting satellites has been used by three groups to monitor the very small trend in the global tropospheric temperature over the 25‐year satellite record. To obtain a homogeneous data set, each group made different calibration corrections of the MSUs in the form of fixed biases, and in some cases temperature‐dependent adjustments, to each of the nine satellite instruments using data during the overlap periods. Up until now, however, the adjustments are empirically based. To improve the accuracy as well as our understanding of the error sources, this paper develops an alternate, physical approach for intercalibrating the MSU instruments. The paper develops a calibration model for the MSU instrument that includes the errors in the cold space and warm target measurements, as well as the nonlinear factor. Corrections for these calibration errors are estimated using a least squares minimization where the predictors are the differences between all 12 overlapping satellite measurements at low and high latitudes. After applying the calibration corrections, the zonally averaged differences between satellite instruments are no larger than 0.03 K, independent of latitude. It is also found that the tropospheric temperature trend derived from MSU measurements is nearly the same as the surface trend. Furthermore, it now appears that much of the earlier inconsistency between the satellite and surface measurements arises from errors in the MSU calibration correction procedure, which can artificially suppress the temperature trend.
Doubled CO2‐induced cooling in the middle atmosphere: Photochemical analysis of the ozone radiative feedback
Authors: Jonsson A. I. , de Grandpré J. , Fomichev V. I. , McConnell J. C. , Beagley S. R.
Published: December 2004

Simple radiative arguments predict that the impact of CO2 increases on the stratosphere and mesosphere should be a cooling and that the magnitude of the temperature change should be significantly larger than in the troposphere. Considering the temperature dependence of middle atmospheric gas‐phase ozone photochemistry, it is expected that the ozone response will generate a radiative feedback that mitigates the CO2‐induced cooling. The magnitude and vertical structure of this signal need to be characterised in order to distinguish the impact of future CO2 changes from other processes affecting the temperature evolution, such as changes in chlorine loading and water vapour trends. The Canadian Middle Atmosphere Model (CMAM) has been used in a process oriented study to examine the details of radiative and photochemical feedbacks under current and doubled CO2 conditions at low and middle latitudes. The model was run both with and without interactive chemistry in order to determine the importance of the radiative feedback through ozone changes on the CO2‐induced cooling signal. Changes in other greenhouse gases, ozone depleting substances, or SST's and sea ice coverage were not considered. The interactive model results show a substantial temperature decrease throughout most of the middle atmosphere with a maximum cooling of 10–12 K at the stratopause. In association with this temperature change, the ozone mixing ratio increases by 15–20% in the upper stratosphere and by 10–15% in the lower mesosphere. Results from the non‐interactive simulations show that the magnitude of the cooling is overestimated by up to ∼4.5 K when the ozone radiative feedback is not considered. In spite of the complexity of the ozone chemistry, the ozone increase at 30–70 km can be understood primarily as a result of the negative temperature dependence of the O + O2 + M → O3 + M reaction that controls odd oxygen partitioning. Additional partial contributions to the ozone increase below 60 km are provided by a decrease in the reaction rate coefficient of the Chapman reaction O + O3 → 2O2 and by a decrease in the NO2 abundance.
Quantification of ozone formation metrics at Thompson Farm during the New England Air Quality Study (NEAQS) 2002
Authors: Griffin Robert J. , Johnson Christina A. , Talbot Robert W. , Mao Huiting , Russo Rachel S. , Zhou Yong , Sive Barkley C.
Published: December 2004

Several metrics have been estimated to investigate preliminarily ozone (O3) formation dynamics at the University of New Hampshire Atmospheric Observing Station at Thompson Farm, which is associated with the Atmospheric Investigation, Regional Modeling, Analysis, and Prediction program. This paper focuses on the August time frame of the New England Air Quality Study 2002. These metrics include instantaneous and net O3 production rate (P(O3)), instantaneous and average O3 production efficiency (OPE), and hydrocarbon and carbon monoxide (CO) reactivity. In general, the seacoast region of New Hampshire experiences low P(O3) values compared to other continental locations. Use of a photochemical model yields a range of instantaneous values of 0.2 to 8.5 ppbv h−1 and a range of net values of 0.2 to 8.3 ppbv h−1. Corresponding calculations for instantaneous OPE range from 0.2 to 2.4, with regression techniques yielding average OPE values of 7.7 and 9.7. These high regression values, the mixing ratios of NOy, and the concentration ratios of O3 to NOz indicate a NOx‐limited atmosphere. Total hydrocarbon and CO reactivity ranges from 0.9 to 20.2 s−1. In conjunction with back trajectory analysis the metric values calculated for this location indicate that strong peaks in O3 during this period are most likely a result of mixing of processed, O3‐rich air masses rather than direct in situ chemical formation.
Factors that inhibit snowball Earth simulation
Authors: Poulsen C. J. , Jacob R. L.
Published: December 2004

A coupled ocean‐atmosphere general circulation model with a thermodynamic sea‐ice model, the Fast Ocean Atmosphere Model version 1.5, is used to investigate the factors that inhibit the simulation of global sea ice. In the control experiment with reduced solar luminosity (93% of modern), low atmospheric pCO2 (140 ppm), and an idealized tropical continent, the sea‐ice margin equilibrates at ∼27° latitude. A series of experiments was completed to systematically test the influence of deep‐ocean circulation, wind‐driven ocean circulation, convective mixing, sea‐ice treatment, and radiative‐cloud forcing, on the sea‐ice extent. Model results indicate that both wind‐driven circulation and cloud‐radiative forcing are critical factors that inhibit sea‐ice advance into the low latitudes. The wind‐driven ocean circulation transports heat to the sea‐ice margin, stabilizing the sea‐ice margin. Clouds yield a positive radiative forcing over ice, warming the air overlying sea ice and decreasing sensible heat loss at the sea‐ice margin. In the absence of either factor, sea ice expands to the equator within 15 model years, yielding a snowball Earth. We also find that intensification of the Hadley circulation as sea ice enters the Hadley domain promotes the climate instability that leads to global sea‐ice cover. Results from this study help explain the wide disparity in conditions necessary to simulate global ice cover in previous climate models of the Neoproterozoic.
Generalized hydraulic geometry: Insights based on fluvial instability analysis and a physical model
Authors: Dodov Boyko , Foufoula‐Georgiou Efi
Published: December 2004

The power law dependencies between channel morphology and river flows, known as at‐station hydraulic geometry (HG), have been recently shown to have exponents that systematically vary with scale (contributing area). To explain these empirical trends, a generalized HG model whose parameters are explicit functions of scale was derived by Dodov and Foufoula‐Georgiou [2004], based on a statistical multiscaling formalism. In this paper we attempt to provide a physical explanation for this scale dependence. The hypothesis we pose is that it arises from the scale dependence of fluvial instability, which induces systematic variation in river planform geometry (e.g., sinuosity, meander wavelength, and radius of curvature) and consequent variations in channel cross‐sectional shape with scale. In other words, we postulate that the scale‐dependent HG is a direct consequence of the systematic increase of channel cross‐sectional asymmetry over reaches of increasing scale. To test this hypothesis, we employ both a direct analysis of observations and also a physical model of meandering rivers, which is based on linearization of the fully coupled equations of mass and momentum balance for water and sediment. We show that the HG emerging from this physical model is scale‐dependent and agrees with the empirical observations and the statistical multiscaling model.
Inducible nitric oxide synthase gene and diabetic retinopathy in Asian Indian patients
Authors: Kumaramanickavel G , Sripriya S , Vellanki RN , Upadyay NK , Badrinath SS , Rajendran V , Sukumar B , Ramprasad VL , Sharma T
Published: December 2004

Nitric oxide, a signal transduction molecule, when modulated causes various diseases including diabetic retinopathy. In diabetes, allelic polymorphism of the inducible nitric oxide synthase (iNOS) gene is associated with retinopathy in the Northern Irish population. In the present study we investigated the Asian Indian population.

One hundred and ninety‐nine unrelated Asian Indian patients with 15 or more years of type 2 diabetes were divided into two groups: (a) diabetic retinopathy (DR) and (b) diabetic nonretinopathy (DNR) subjects. In these groups the pentanucleotide microsatellite repeat located 2.5 kb upstream of the transcription start site of the iNOS gene was amplified by polymerase chain reaction and analyzed.

Eleven alleles, 175–225 bp, were identified. Allele 210 bp was significantly associated with retinopathy (p = 0.044). Individuals carrying this allele had twice the risk of developing retinopathy compared with those who did not carry this allele [odds ratio (OR) – 2.03; 95% CI 0.96–4.35]. Alleles 200 and 220 bp were also significantly associated with no retinopathy and no serious retinopathy complications, respectively.

In the Asian Indian population, allele 210 bp of the iNOS gene is a high‐risk allele for developing retinopathy and alleles 200 and 220 bp protect an individual from developing retinopathy or its complications.
Why are we ‘weighting’? An assessment of a self‐weighting approach to measuring oral health‐related quality of life
Authors: McGrath Colman , Bedi Raman
Published: December 2004

Abstract  – 

Objective: To determine whether or not self‐weighting at an item level contributes to the performance of an oral health‐related quality‐of‐life measure.

Design: Data were collected in two national surveys conducted a month apart, one using the ‘weighted’ measure and the other an ‘unweighted’ version of the UK oral health‐related quality‐of‐life measure. In addition, sociodemographic and self‐reported oral health status were recorded.

Results: The UK oral health‐related quality‐of‐life measure discriminated between groups based on age group (<65, 65 and older) and social class (higher and lower) irrespective of the version of the questionnaire used. Both versions also showed significant associations with self‐reported oral health: denture status (P < 0.01) and number of teeth possessed (P < 0.01). In addition, both versions demonstrated predictive ability in identifying those in prosthetic need (<20 teeth and without recourse to a denture, P < 0.01).

Conclusion: Weighting the UK oral health‐related quality‐of‐life instrument does not improve the psychometric properties of the instrument and thus raises questions about the value of self‐weighting at an item level.
Effects of electromagnetic radiation from a cellular telephone on epidermal Merkel cells
Authors: Irmak M. Kemal , Oztas Emin , Yagmurca Murat , Fadillioglu Ersin , Bakir Bilal
Published: December 2004

The number of reports on the effects induced by electromagnetic radiation (EMR) from cellular telephones in various cellular systems is still increasing. Until now, no satisfactory mechanism has been proposed to explain the biological effects of this radiation except a role suggested for mast cells. Merkel cells may also play a role in the mechanisms of biological effects of EMR. This study was undertaken to investigate the influence of EMR from a cellular telephone (900 MHz) on Merkel cells in rats. A group of rats was exposed to a cellular telephone in speech position for 30 min. Another group of rats was sham‐exposed under the same environmental conditions for 30 min. Exposure led to significantly higher exocytotic activity in Merkel cells compared with the sham exposure group. This finding may indicate the possible role of Merkel cells in the pathophysiology of the effects of EMR.
Activation of nuclear factor‐kappa B and macrophage invasion in cyclosporin A‐ and tacrolimus‐treated renal transplants
Authors: Mizuiri Sonoo , Iwamoto Masateru , Miyagi Moriatsu , Kawamura Takeshi , Sakai Ken , Arai Kenji , Aikawa Atsushi , Ohara Takehiro , Hemmi Hiromichi , Hasegawa Akira
Published: December 2004

Abstract:  This retrospective study was designed to compare the efficacy of cyclosporin A (CyA) and tacrolimus (FK506) on chronic rejection (CR) associated with nuclear factor‐kappa B (NF‐κB) activation and macrophage invasion. Non‐episodic day 50 protocol renal biopsy was performed in 63 consecutive patients with renal transplants from living donors, treated with either CyA or FK506. Southwestern histochemistry for NF‐κB, immunostaining for CD68, and Banff classification were performed, and these findings were compared with outcome over 34 ± 13 months. Compared with specimens from FK506‐treated patients (n = 20), specimens from CyA‐treated patients (n = 43) showed a significant increase in tubulointerstitial CD68‐positive cells (1.5 ± 0.9 vs. 0.9 ± 0.8, p < 0.01), although no significant differences were observed in NF‐κB activation. Specimens with Banff acute rejection (AR) grade ≥ 1A (n = 20) showed increased macrophages (p < 0.01) compared with specimens with AR < 1A (n = 43). Specimens from patients with clinical AR prior to day 50 biopsy (n = 23) also showed increased macrophage invasion (p < 0.01) compared with specimens from patients without prior clinical AR (n = 40). The cumulative well‐functioning (serum creatinine <1.5 mg/dL) graft survival rate was significantly lower in patients with increased tubulointerstitial CD68‐positive cells (n = 63, p < 0.05). Our findings suggest that tacrolimus is more effective than CyA against CR with respect to macrophage invasion and AR.
Cytomegalovirus ischemic colitis of a diabetic renal transplant recipient
Authors: Chang Horng‐Rong , Lian Jong‐Da , Chan Chi‐Ho , Wong Lai‐Ching
Published: December 2004

Abstract: We report a diabetic renal transplant recipient with cytomegalovirus (CMV) disease who presented with tarry stool diarrhea because of multiple colonic ulcerations. Histopathology revealed diffuse colonic ulcers following a process of ischemic vasculitis. The colonic ulcers disappeared dramatically after 2 wk of intravenous ganciclovir therapy. Hyper‐immunosuppression was initially suspected but acute rejection (AR) developed after immunosuppressive reduction during the ganciclovir therapy. The AR was successfully reversed and the dosage of cyclosporine was returned to the same level prior to the onset of CMV disease. Our experience suggests that ganciclovir is quite effective for healing colonic ulcers caused by CMV and acute allograft rejection may occur during therapy.
Improving diagnostic yield of biliary brushings cytology for pancreatic cancer and cholangiocarcinoma
Authors: Wight C. O. , Zaitoun A. M. , Boulton‐Jones J. R. , Dunkley C. , Beckingham I. J. , Ryder S. D.
Published: December 2004

Biliary brushings are currently the best accepted method to obtain a cytological diagnosis of pancreatic cancer or cholangiocarcinoma. The technique has good specificity but poor sensitivity. Two dedicated pathologists reviewed 137 consecutive biliary brushings from 127 patients between February 1997 and February 2000. The ultimate diagnosis was determined by review of radiology, operative diagnosis and patient outcome. The sensitivity, specificity, positive predictive value and negative predictive value of the original results and the review results were calculated and compared. Additional diagnostic categories ‘suspicious’ and ‘atypical possibly benign’ were included on review. After review, the sensitivity improved from 49.4% to 89.0% and the specificity remained 100%. The use of the additional diagnostic category ‘suspicious’ increased the sensitivity to 90.4%, at the expense of a fall of the specificity to 66.7%. We conclude that review by two dedicated pathologists and additional diagnostic categories can improve the diagnostic accuracy of biliary brushings.
Distinguishing fault reactivation from flexural deformation in the distal stratigraphy of the Peripheral Blountian Foreland Basin, southern Appalachians, USA
Authors: Bayona Germán , Thomas William A.
Published: December 2004

Reactivation of intraplate structures and weak zones within the foreland lithosphere disrupt the modelled geometry and pattern of migration of the flexural wave in foreland basins. In the southern Appalachians (USA), the Middle Ordovician unconformity, irregular Middle Ordovician distal foreland deposition and backstepping of Middle–lower Upper Ordovician carbonate strata have been related to migration of the flexural wave. However, integration of stratigraphy, tectonic subsidence history and composition of palinspastically restored distal foreland strata, using a map of subsurface basement structures as reference, allows us to distinguish an early event of inversion from two events of flexural migration. Sections restoring at very short distances outside the boundaries of a former basement graben have the youngest passive‐margin strata preserved beneath Middle Ordovician (∼466 Ma) peritidal to deep lagoonal carbonates with gravel‐size chert clasts. In contrast, sections restoring inside the graben record >470 m of truncation of pre‐Middle Ordovician passive‐margin strata, late onset of deposition (∼456 Ma), and subaerial features in carbonate and siliciclastic strata. The lacuna geometry and early patterns of distal foreland uplift and carbonate deposition indicate that inversion of a basement graben in response to Middle Ordovician convergence, rather than a migrating or semi‐fixed forebulge, was the primary control on the early evolution of the distal foreland. Drowning of the carbonate platform in more proximal settings, northeastward onset of deposition on upthrown blocks, and thick accumulation of carbonates in downthrown blocks record northwestward and northeastward flexural wave migration at the Middle–Late Ordovician boundary. In early Late Ordovician, the overall shoaling of carbonate and siliciclastic depocentres and the rise of tectonic subsidence curves indicate hinterlandward migration of flexural uplift. Both events of flexural migration were accompanied by influx of volcanic ash and synorogenic sediments.
Long‐term survival in multiple myeloma: a Finnish Leukaemia Group study
Authors:   Finnish Leukaemia Group
Published: December 2004

The long‐term survival of 324 multiple myeloma patients treated with conventional chemotherapy (CT) was analysed after at least 10 years follow‐up. The unselected group of myeloma patients 70 years, as representative of the population, was derived from three prospective multicentre trials by the Finnish Leukaemia Group.

The median overall survival time (OS) was 49 months. At 10 years, 13% of the patients were alive. The significant single pre‐treatment prognostic factors for long‐term survival were age, Hb, platelet count, serum‐creatinine and proportion of plasma cells in the bone marrow. Staging according to Hb level and plasma cell degree was more useful than that of the Durie and Salmon system in predicting long‐term survival. The first‐line chemotherapy combination and the level of response were unimportant in this respect. A long plateau phase after first response and response to salvage chemotherapy were important prognostic factors. Not only the salvage regimen but also the whole supportive treatment and adequate control of complications throughout the course of the disease are important.