bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of X‐ray beam angulation for successful twin canal identification in mandibular incisors
Authors: KLEIN R. M. F. , BLAKE S. A. , NATTRESS B. R. , HIRSCHMANN P. N. 
Published: April 2006

SummaryThis study was undertaken to determine the most effective horizontal beam angulation for the diagnosis of twin canals in mandibular incisors. Two hundred extracted mandibular incisor teeth, in groups of four, were aligned in the form of a lower dental arch and radiographed using a beam alignment device at 10° intervals between 0° and 50° from both right and left sides. Five observers with varying degrees of experience were asked to assess the number of canals in each of the four teeth from these radiographs. A further radiograph of each individual tooth was taken at 90° through the mesio‐distal plane to identify the number of twin canals present. A random sample of 10% of the radiographs were viewed for a second time 3 months later to assess intra‐observer variation. The 20° right and 30° left horizontal beam angulations showed significantly more accurate diagnosis of twin canals than the ortho‐radial view (0°) by all five observers. Analysis of the inter‐observer results suggests that the experienced viewers were no better but more consistent at identifying twin canals in mandibular incisors.
General obstetrics: Failing pregnancies of unknown location: a prospective evaluation of the human chorionic gonadotrophin ratio
Authors: Condous G , Kirk E , Van Calster B , Van Huffel S , Timmerman D , Bourne T 
Published: April 2006

Objective  To assess the performance of the human chorionic gonadotrophin (hCG) ratio (hCG 48 hours/hCG 0 hour) to predict spontaneous resolution of pregnancies of unknown location (PUL).Design  Prospective cohort study.Setting  Teaching Hospital Early Pregnancy Unit.Population  Women classified as having a PUL.Methods  The optimal cutoff value for hCG ratio (serum hCG at 48 hours/serum hCG at 0 hours) was calculated from data on 189 consecutive PULs (the ‘training set’). This cutoff was tested prospectively on a further 200 consecutive PULs (the ‘test set’). The hCG ratio was also compared to absolute levels of serum hCG at 0 and 48 hour for the prediction of failing PULs.Main outcome measures  hCG ratio in spontaneously resolving (‘failing’) PUL compared with those requiring intervention. Optimum cutoff determined and tested to predict spontaneously resolving PUL. Comparison of hCG ratio with absolute levels of serum hCG.Results  A total of 3996 consecutive women were scanned, of which 438 (11.0%) were classified as PULs. Complete data were available for 389 women: 189 in the training set and 200 in the test set. In the training set, there were 102 (54%) failing PUL, while 109 (55%) in the test set. hCG ratio of <0.87 predicted failing PUL, with a sensitivity of 93.1% (95% CI 85.9–97.0) and a specificity of 90.8% (95% CI 82.2–95.7) in the training set. In the test set, sensitivity was 92.7% (95% CI 85.6–96.5) and specificity was 96.7% (95% CI 90.0–99.1). The hCG ratio outperformed absolute serum hCG levels at 0 and 48 hours.Conclusions  We have defined the optimal hCG ratio for the prediction of failing PUL. Using this cutoff, clinicians can safely adopt a noninterventional approach in women with PUL.
A Simple Multicloud Parameterization for Convectively Coupled Tropical Waves. Part I: Linear Analysis
Authors: Khouider Boualem , Majda Andrew J. 
Published: April 2006

AbstractRecent observational analysis reveals the central role of three multicloud types, congestus, stratiform, and deep convective cumulus clouds, in the dynamics of large-scale convectively coupled Kelvin waves, westward-propagating two-day waves, and the Madden–Julian oscillation. A systematic model convective parameterization highlighting the dynamic role of the three cloud types is developed here through two baroclinic modes of vertical structure: a deep convective heating mode and a second mode with low-level heating and cooling corresponding respectively to congestus and stratiform clouds. A systematic moisture equation is developed where the lower troposphere moisture increases through detrainment of shallow cumulus clouds, evaporation of stratiform rain, and moisture convergence and decreases through deep convective precipitation. A nonlinear switch is developed that favors either deep or congestus convection depending on the relative dryness of the troposphere; in particular, a dry troposphere with large convective available potential energy (CAPE) has no deep convection and only congestus clouds. The properties of the multicloud model parameterization are tested by linearized analysis in a two-dimensional setup with no rotation with constant sea surface temperature. In particular, the present study reveals new mechanisms for the large-scale instability of moist gravity waves with features resembling observed convectively coupled Kelvin waves in realistic parameter regimes without any effect of wind-induced surface heat exchange (WISHE). A detailed dynamical analysis for the linear waves is given herein and idealized nonlinear numerical simulations are reported in a companion paper. A maximum congestus heating leads during the dry phase of the wave. It is followed by an increase of the boundary layer θe, that is, CAPE, and lower troposphere moistening that precondition the upper troposphere for the next deep convective episode. In turn, deep convection consumes CAPE and removes moisture, thus yielding the dry episode.
Variability of the Overflow Water Transport in the Western Subpolar North Atlantic, 1950–97
Authors: Kieke Dagmar , Rhein Monika 
Published: April 2006

Abstract
One of the major topics in current field research is the question of whether or to what extent the North Atlantic Ocean is subject to changes in water mass transports, and how they are related to atmospheric phenomena like the North Atlantic Oscillation (NAO). Bottle and CTD data from the 1950s to 1990s are presented to reconstruct spatially and temporally the baroclinic contribution to the deep water transports in the western subpolar North Atlantic. The focus is on the two densest components of North Atlantic Deep Water: the Gibbs Fracture Zone Water (GFZW) and the Denmark Strait Overflow Water (DSOW). Direct velocity measurements in the considered time period are sparse. For this reason it was decided to calculate the geostrophic velocity relative to 1400 dbar. This level is located in the weakly stratified Labrador Sea Water. The combined baroclinic volume transport of GFZW and DSOW during the early 1990s was about 5 Sv (Sv ≡ 106 m3 s−1) in the Irminger Sea and 7–8 Sv in the Labrador Sea. Near the Flemish Cap, baroclinic transports reached 16–29 Sv. Because of the impact of the North Atlantic Current on the flow field resulting in steeply sloping isopycnals, the latter estimate is strongly dependent on the choice of the reference level, in contrast to other locations. Time series were obtained from data in the Irminger and Labrador Seas. In the Irminger Sea, the combined baroclinic transport of GFZW and DSOW increased from 4–5 Sv in the mid-1950s to 8–9 Sv in the 1980s, followed by a decrease to 5 Sv in the 1990s. In the Labrador Sea, the temporal variability was stronger (3–11 Sv), with interannual changes of 5–6 Sv. The importance of baroclinic transport variability is not easy to interpret. Results presented herein indicate that relations of the Irminger and Labrador Seas time series to the NAO remain ambiguous. Among other impacts the presence of eddies significantly affects the time series of baroclinic transport. Whether baroclinic variability represents the total variability of the flow (baroclinic and barotropic part) cannot be assessed without knowledge of the variability of the velocity field in the reference level.
Stochastic Forcing of the North Atlantic Wind-Driven Ocean Circulation. Part I: A Diagnostic Analysis of the Ocean Response to Stochastic Forcing
Authors: Chhak Kettyah C. , Moore Andrew M. , Milliff Ralph F. , Branstator Grant , Holland William R. , Fisher Michael 
Published: April 2006

Abstract
At midlatitudes, the magnitude of stochastic wind stress forcing due to atmospheric weather is comparable to that associated with the seasonal cycle. Stochastic forcing is therefore likely to have a significant influence on the ocean circulation. In this work, the influence of the stochastic component of the wind stress forcing on the large-scale, wind-driven circulation of the North Atlantic Ocean is examined. To this end, a quasigeostrophic model of the North Atlantic was forced with estimates of the stochastic component of wind stress curl obtained from the NCAR Community Climate Model. Analysis reveals that much of the stochastically induced variability in the ocean circulation occurs in the vicinity of the western boundary and some major bathymetric features. Thus, the response is localized even though the stochastic forcing occurs over most of the ocean basin. Using the ideas of generalized stability theory, the stochastically induced response in the ocean circulation can be interpreted as a linear interference of the nonorthogonal eigenmodes of the system. This linear interference process yields transient growth of stochastically induced perturbations. By examining the model pseudospectra, it is seen that the nonnormal nature of the system enhances the transient growth of perturbation enstrophy and therefore elevates and maintains the variance of the stochastically induced circulations in the aforementioned regions. The primary causes of nonnormality in the enstrophy norm are bathymetry and the western boundary current circulation.
Temporal Changes in Ocean Eddy Transports
Authors: Stammer Detlef , Wunsch Carl , Ueyoshi Kyozo 
Published: April 2006

Abstract
New estimates from 11 yr of altimetric data are made of the global time-average variability kinetic energy and its decadal-scale variability. Making the approximation that the variability reflects primarily eddy motions, a time-mean, but spatially varying, eddy mixing coefficient is then estimated along with its changes over the last decade. With a record length more than 2 times that previously available, the time-mean variability kinetic energy KE is statistically more reliable and smoother in its spatial pattern. Minimum values of KE are present in the subpolar North Pacific Ocean and in the eastern South Pacific (both less than 100 cm2 s−2). In contrast to the North Pacific, the subpolar North Atlantic Ocean shows relatively enhanced KE. Eddy kinetic energy and eddy mixing appear to have declined during the last decade over large parts of the western Pacific Ocean, in some regions by as much as 50% of the time-mean value. Increased eddy variability can be found in the Kuroshio and Gulf Stream regions, as well as in the Agulhas region, east of Australia, and at several locations along the Antarctic Circumpolar Current. Somewhat enhanced eddy variability and eddy mixing are also apparent in the eastern tropical Pacific. A numerical simulation of the ocean circulation at 1° spatial resolution over a 10-yr period suggests that variations in eddy mixing of this order of magnitude measurably affect the deep temperature field in the vicinity of permanent frontal structures on a time scale of less than 4 yr. The meridional overturning circulation also reacts on these time scales. If persistent over longer periods in the ocean, these effects would be important for climate simulations.
The Meridional Flow of Source-Driven Abyssal Currents in a Stratified Basin with Topography. Part II: Numerical Simulation
Authors: Swaters Gordon E. 
Published: April 2006

Abstract
A numerical simulation is described for source-driven abyssal currents in a 3660 km × 3660 km stratified Northern Hemisphere basin with zonally varying topography. The model is the two-layer quasigeostrophic equations, describing the overlying ocean, coupled to the finite-amplitude planetary geostrophic equations, describing the abyssal layer, on a midlatitude β plane. The source region is a fixed 75 km × 150 km area located in the northwestern sector of the basin with a steady downward volume transport of about 5.6 Sv (Sv ≡ 106 m3 s−1) corresponding to an average downwelling velocity of about 0.05 cm s−1. The other parameter values are characteristic of the North Atlantic Ocean. It takes about 3.2 yr for the abyssal water mass to reach the southern boundary and about 25 yr for a statistical state to develop. Time-averaged and instantaneous fields at a late time are described. The time-averaged fields show an equatorward-flowing abyssal current with distinct up- and downslope groundings with decreasing height in the equatorward direction. The average equatorward abyssal transport is about 8 Sv, and the average abyssal current thickness is about 500 m and is about 400 km wide. The circulation in the upper layers is mostly cyclonic and is western intensified, with current speeds about 0.6 cm s−1. The upper layer cyclonic circulation intensifies in the source region with speeds about 4 cm s−1, and there is an anticyclonic circulation region immediately adjacent to the western boundary giving rise to a weak barotropic poleward current in the upper layers with a speed of about 0.6 cm s−1. The instantaneous fields are highly variable. Even though the source is steady, there is a pronounced spectral peak at the period of about 54 days. The frequency associated with the spectral peak is an increasing function of the downwelling volume flux. The periodicity is associated with the formation of transient cyclonic eddies in the overlying ocean in the source region and downslope propagating plumes and boluses in the abyssal water mass. The cyclonic eddies have a radii about 100–150 km and propagation speeds about 5–10 cm s−1. The eddies are formed initially because of stretching associated with the downwelling in the source region. Once detached from the source region, the cyclonic eddies are phase locked with the boluses or plumes that form on the downslope grounding of the abyssal current, which themselves form because of baroclinic instability. Eventually, the background vorticity gradients associated with β and the sloping bottom arrest the downslope (eastward) motion, the abyssal boluses diminish in amplitude, the abyssal current flows preferentially equatorward, the upper layer eddies disperse and diminish in amplitude, and westward intensification develops.
An Exact Energy for TRM Theory
Authors: Jacobson Tivon , Aiki Hidenori 
Published: April 2006

Abstract
A time residual mean (TRM) energy is obtained by averaging a transformation of the energy of the Boussinesq hydrostatic incompressible equations of motion. The transformation is the fundamental TRM transformation between level Cartesian coordinates and coordinates that are the mean positions of density surfaces. The TRM energy consists of a sum of mean kinetic, mean potential, wave kinetic, and wave potential energies. It is shown that the interaction between the mean kinetic energy and mean potential energy can be expressed entirely in terms of mean fields. The wave forcing of the mean TRM momentum equations is expressed as a divergence. An explicit and exact form of the TRM equations, with the transformed pressure term expressed in terms of the mean and wave fields, is also noted. It is suggested that the mean domain for the TRM equations and the Cartesian domain may not be the same, which would have consequences for the TRM boundary conditions.
Baroclinic Development in Observations and NASA GSFC General Circulation Models
Authors: Robinson Dennis P. , Black Robert X. 
Published: April 2006

Abstract
Comparative diagnostic analyses of developing synoptic-scale baroclinic disturbances in NCEP–NCAR reanalyses and the NASA–NCAR (NASCAR) and Aries [NASA’s Seasonal-to-Interannual Prediction Project (NSIPP)] general circulation model simulations are performed. In particular, lag composite analyses of wintertime cyclonic and anticyclonic events occurring in the North Pacific and North Atlantic storm tracks are constructed to pursue a synoptic and dynamic characterization of eddy development. The data are also seasonally stratified to study aspects of the North Pacific midwinter suppression phenomenon.
Winter-averaged results indicate that the model-simulated events are generally too weak in amplitude, particularly in the upper troposphere. For the North Pacific storm track, model-simulated events are also anomalously distended in the meridional direction. The existing model biases in eddy structure and magnitude lead to anomalously weak baroclinic energy conversions for both cyclonic and anticyclonic events over the North Pacific. For the North Atlantic storm track the NASCAR model provides a very good representation of the structure of developing cyclonic events. However, growing North Atlantic cyclones in the NSIPP model are anomalously weak and horizontally too isotropic (meridionally retracted). These latter two characteristics are also observed in both models for developing anticyclonic flow anomalies over the North Atlantic. The relative weakness of NSIPP synoptic events over the North Atlantic region is largely responsible for the 50% deficiency in areal-averaged baroclinic energy conversions. Conversely, the NASCAR model climatology features anomalously strong temperature gradients over the western North Atlantic that provide local enhancements to the baroclinic energy conversion field.
A seasonally stratified diagnostic analysis reveals that the simulated climatological storm tracks over the North Pacific undergo larger spatial migrations during the cool season compared to observations. It is further determined that the suppression of synoptic eddy activity observed in the Pacific storm track is associated with a relative midwinter weakness in the magnitude of the growing cyclonic anomalies. Specifically, during midwinter the cyclonic perturbations entering the Pacific storm track are deficient in magnitude compared to their early and late winter counterparts. It is also discovered that the midwinter suppression pattern over the North Pacific region has a clear organized extension upstream into Siberia, the region from which incipient upper-tropospheric short-wave features emanate. This behavior is found in both observations and the model simulations. The results herein support the idea that the North Pacific midwinter suppression phenomenon is linked to a midwinter weakness in the upstream formation of upper-level short waves, leading to anomalously weak “seeding” of baroclinic disturbances in the Pacific storm track.
Interpretation of Enhanced Integrated Water Vapor Bands Associated with Extratropical Cyclones: Their Formation and Connection to Tropical Moisture
Authors: Bao J-W. , Michelson S. A. , Neiman P. J. , Ralph F. M. , Wilczak J. M. 
Published: April 2006

Abstract
Trajectory analysis using a weather prediction model is performed for five cases to interpret the formation of enhanced bands of vertically integrated water vapor (IWV) in the central and eastern Pacific that are frequently seen in satellite images from the Special Sensor Microwave Imager. The connection of these enhanced bands with poleward water vapor transport from the Tropics is also examined. It is shown that the leading end of the enhanced IWV bands (defined as the most eastward and poleward end) is the manifestation of moisture convergence in the warm conveyor belt associated with extratropical cyclones, while the bands away from the leading end result mainly from moisture convergence along the trailing cold fronts. There is evidence that some enhanced IWV bands may be associated with a direct poleward transport of tropical moisture along the IWV bands from the Tropics all the way to the extratropics. The trajectory analysis, together with the seasonal mean sea level pressure analysis, indicates that a favorable condition for the occurrence of a direct, along-IWV band transport of tropical (defined as south of 23.5°N) moisture to the U.S. West Coast in the eastern Pacific is a weakened subtropical ridge in the central Pacific with an enhanced southwesterly low-level flow. The authors hypothesize that the direct poleward transport of tropical moisture within an enhanced IWV band in the eastern Pacific is most possible in the neutral El Niño–Southern Oscillation (ENSO) phase and is least possible in the El Niño phase.
Azusa-Era Optimism: Bishop J.H. King’s Pentecostal Theology of Religions as a Possible Paradigm for Today
Authors: Richie Tony 
Published: April 2006

AbstractEven as we celebrate the centennial of the Azusa Street Revival, the ideology and reality of religious pluralism currently challenges Pentecostal Christians to articulate an adequate theology of religions. J.H. King was an important Pentecostal pioneer influenced by the Azusa Street Revival. Well educated and widely traveled, Bishop King had considerable first-hand contact with non-Christian religions and addressed theology of religions often and in depth. King’s theology of religions at its core is characterized by optimism, that is, by a positive and balanced but non-dogmatic sense of hopefulness. Completely consistent with classical Pentecostal values, King’s thought provides important possibilities for a contemporary Pentecostal theology of religions paradigm. This paper surveys salient features of King’s theology of religions before offering suggestions about appropriation and application. Special stress is placed on continuity of Pentecostal heritage with creativity in development of Pentecostal theology of religions today.
Pontine Atypical Neurocytoma: Case Report
Authors: Swinson Bradley M. , Friedman William A. , Yachnis Anthony T. 
Published: April 2006

Abstract

OBJECTIVE AND IMPORTANCE:
Neurocytomas are typically located within the supratentorial ventricular system. Extraventricular neurocytomas are very rare, and this is only the second reported case of a pontine neurocytoma. We discuss the clinical presentation, histology, and treatment of these rare tumors.

CLINICAL PRESENTATION:
A 58-year-old man presented with a 4-month history of headache and unilateral facial and distal extremity paresthesia. Magnetic resonance imaging (MRI) scans demonstrated a 2.6 × 2.2-cm ring-enhancing cystic mass in the right pons.

INTERVENTION:
MRI-guided stereotactic biopsy yielded a diagnosis of atypical neurocytoma. Because of the location and malignant histological features of the tumor, the patient was initially treated with external beam radiation therapy. Several months later, MRI scans demonstrated tumor progression. The patient then underwent three rounds of temozolomide chemotherapy, during and after which his symptoms worsened. Aggressive subtotal resection of the tumor was achieved via a right suboccipital craniectomy.

CONCLUSION:
Twenty-eight months postoperatively, the patient is symptom free, and MRI scans demonstrate no evidence of residual or recurrent tumor.