bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multicloud Models for Organized Tropical Convection: Enhanced Congestus Heating
Authors: Khouider Boualem , Majda Andrew J. 
Published: March 2008

Abstract
Despite the recent advances in supercomputing, the current general circulation models (GCMs) poorly represent the large-scale variability associated with tropical convection. Multicloud model convective parameterizations based on three cloud types (congestus, deep, and stratiform), introduced recently by the authors, have been revealed to be very useful in representing key features of organized convection and convectively coupled waves. Here a new systematic version of the multicloud models is developed with separate upper- and lower-troposphere basis functions for the congestus and stratiform clouds. It naturally leads to a new convective closure for the multicloud models enhancing the congestus heating in order to better pinpoint the congestus preconditioning and moistening mechanisms. The models are studied here for flows above the equator without rotation effects. First, the new model results consist of the usual synoptic-scale convectively coupled moist gravity wave packets moving at 15–20 m s−1 but, in addition, these packets have planetary-scale envelopes moving in the opposite direction at about 6 m s−1 and have many of the self-similar features of convectively coupled waves, reminiscent of the Madden–Julian oscillation. Second, when a warm pool forcing is imposed, dry regions of roughly 250 km in extent form “convective barriers” surrounding the warm pool region where only congestus heating survives. Deep convection and moist gravity waves are thus confined within the warm pool region. Finally, linear analysis reveals that, for sufficiently dry mean states, in addition to the inherent synoptic-scale moist gravity waves, the new model supports a planetary (wavenumber 1) standing congestus mode that provides, within its congestus active phase, a region where moist gravity waves evolve and propagate, which results in a Walker-like circulation over a uniform SST background.
Eddy-Mediated Regime Transitions in the Seasonal Cycle of a Hadley Circulation and Implications for Monsoon Dynamics
Authors: Schneider Tapio , Bordoni Simona 
Published: March 2008

Abstract
In a simulation of seasonal cycles with an idealized general circulation model without a hydrologic cycle and with zonally symmetric boundary conditions, the Hadley cells undergo transitions between two regimes distinguishable according to whether large-scale eddy momentum fluxes strongly or weakly influence the strength of a cell. The center of the summer and equinox Hadley cell lies in a latitude zone of upper-level westerlies and significant eddy momentum flux divergence; the influence of eddy momentum fluxes on the strength of the cell is strong. The center of the cross-equatorial winter Hadley cell lies in a latitude zone of upper-level easterlies and is shielded from the energy-containing midlatitude eddies; the influence of eddy momentum fluxes on the strength of the cell is weak. Mediated by feedbacks between eddy fluxes, mean zonal winds at upper levels, and the mean meridional circulation, the dominant balance in the zonal momentum equation at the center of a Hadley cell shifts at the transitions between the regimes, from eddies dominating the momentum flux divergence in the summer and equinox cell to the mean meridional circulation dominating in the winter cell. At the transitions, a feedback involving changes in the strength of the lower-level temperature advection and in the latitude of the boundary between the winter and summer cell is responsible for changes in the strength of the cross-equatorial winter cell. The transitions resemble the onset and end of monsoons, for example, in the shift in the dominant zonal momentum balance, rapid shifts in the latitudes of maximum meridional mass flux and of maximum convergence at lower levels, rapid changes in strength of the upward mass flux, and changes in direction and strength of the zonal wind at upper and lower levels. In the monsoonal regime, the maximum upward mass flux occurs in an off-equatorial convergence zone located where the balance of the meridional geopotential gradient in the planetary boundary layer shifts from nonlinear frictional to geostrophic. Similar dynamic mechanisms as at the regime transitions in the simulation—mechanisms that can act irrespective of land–sea contrasts and other inhomogeneities in lower boundary conditions—may be implicated in large-scale monsoon dynamics in Earth’s atmosphere.
Dynamics of Eddy-Driven Low-Frequency Dipole Modes. Part IV: Planetary and Synoptic Wave-Breaking Processes during the NAO Life Cycle
Authors: Luo Dehai , Gong Tingting , Diao Yina 
Published: March 2008

Abstract
Based on a highly idealized, analytical solution of the North Atlantic Oscillation (NAO) derived in Part III of this series, it is shown that wave breaking is not a necessary condition for the occurrence of NAO events. The breaking of synoptic waves can arise from the interaction between planetary and synoptic waves that gives rise to NAO events, and the type of wave breaking is dominated by the initial conditions of the two waves that determine the phase of the NAO. The planetary wave breaking (PWB) seems to be attributed to an amplification of the NAO amplitude. It is further found that both the planetary wave breaking and the cyclonic (anticyclonic) breaking of synoptic waves undergo an in-phase (out phase) evolution during the life cycles of negative (positive) phase NAO, or NAO− (NAO+), events. An interesting result found is that for NAO− (NAO+) events the breaking of synoptic waves is enhanced (weakened) during the growing phase, but is weakened (enhanced) during the decaying phase.
In the absence of a topographic planetary wave (TPW), PWB occurs mainly in the midlatitude regions of the Atlantic basin for NAO− events, but is concentrated in subtropical and subpolar regions for NAO+ events. However, once the TPW is involved, the reversed planetary-scale potential vorticity (PV) gradient that characterizes the PWB exhibits a southwest–northeast (southeast–northwest) tilted tripole for NAO− (NAO+) events, in agreement with the diagnostic results presented herein. The PWB in the subtropical Atlantic is found to occur more frequently for NAO+ events than for NAO− events because the weaker subtropical mean flow is more likely to emerge during the NAO+ life cycle. In conclusion, the results of the highly idealized model used here appear to show that the PWB, synoptic wave breaking, and meridional shift of the westerly jet may be different descriptions of the NAO phenomenon.
Hurricane Vortex Dynamics during Atlantic Extratropical Transition
Authors: Davis Christopher A. , Jones Sarah C. , Riemer Michael 
Published: March 2008

AbstractSimulations of six Atlantic hurricanes are diagnosed to understand the behavior of realistic vortices in varying environments during the process of extratropical transition (ET). The simulations were performed in real time using the Advanced Research Weather Research and Forecasting (WRF) model (ARW), using a moving, storm-centered nest of either 4- or 1.33-km grid spacing. The six simulations, ranging from 45 to 96 h in length, provide realistic evolution of asymmetric precipitation structures, implying control by the synoptic scale, primarily through the vertical wind shear.The authors find that, as expected, the magnitude of the vortex tilt increases with increasing shear, but it is not until the shear approaches 20 m s−1 that the total vortex circulation decreases. Furthermore, the total vertical mass flux is proportional to the shear for shears less than about 20–25 m s−1, and therefore maximizes, not in the tropical phase, but rather during ET. This has important implications for predicting hurricane-induced perturbations of the midlatitude jet and its consequences on downstream predictability.Hurricane vortices in the sample resist shear by either adjusting their vertical structure through precession (Helene 2006), forming an entirely new center (Irene 2005), or rapidly developing into a baroclinic cyclone in the presence of a favorable upper-tropospheric disturbance (Maria 2005). Vortex resiliency is found to have a substantial diabatic contribution whereby vertical tilt is reduced through reduction of the primary vortex asymmetry induced by the shear. If the shear and tilt are so large that upshear subsidence overwhelms the symmetric vertical circulation of the hurricane, latent heating and precipitation will occur to the left of the tilt vector and slow precession. Such was apparent during Wilma (2005).
Reply
Authors: Schultz David M. , Durant Adam J. , Straka Jerry M. , Garrett Timothy J. 
Published: March 2008

Abstract
Doswell has proposed a mechanism for mammatus called double-diffusive convection, the mechanism responsible for salt fingers in the ocean. The physics of salt fingers and mammatus are different. Unlike the ocean where the diffusivity is related to molecular motions within solution, the hydrometeors in clouds are affected by inertial and gravitational forces. Doswell misinterprets the vertical temperature profiles through mammatus and fails to understand the role of settling in volcanic ash clouds. Furthermore, given that mixing is a much more effective means of transferring heat in the atmosphere and given idealized numerical model simulations of mammatus showing that the destabilizing effect of subcloud sublimation is an effective mechanism for mammatus, this reply argues that double-diffusive convection is unlikely to explain mammatus, either in cumulonimbus anvils or in volcanic ash clouds.
An Analysis of Precipitation Variability, Persistence, and Observational Data Uncertainty in the Western United States
Authors: Guirguis Kristen J. , Avissar Roni 
Published: March 2008

Abstract
This paper presents an intercomparison of precipitation observations for the western United States. Using nine datasets, the authors provide a comparative climatology and season- and location-specific evaluations of precipitation uncertainty for the western United States and for five subregions that have distinct precipitation climates. All data are shown to represent the general climate features but with high bias among datasets. Interannual variability is similar among datasets with respect to the timing of precipitation excesses and deficits, but important differences occur in the spatial distribution of specific anomalous events. Dataset distribution differences, as represented by their cumulative density functions (CDFs), are statistically significant for 80% of data combinations stratified by subregion and season. The CDFs of anomaly fields are more similar but uncertainty remains, as data differences are significant for 40% of dataset comparisons. Observational uncertainty is low for persistence studies because the data are found to be similar with respect to (i) grid cell estimates of a characteristic persistence time scale and (ii) distributions of anomaly length scales. Spatially, the greatest uncertainty in magnitude differences occurs along the Rocky Mountains in winter, spring, and fall, and along the California coastline in summer. In linear (phase) association, the greatest differences occur in northern Mexico during all seasons; along the Rocky Mountains in winter, spring, and fall; and in California, Nevada, and the intermountain region in summer. Overall, data similarity is lowest in summer as a result of a reduction in phase association and an increase in amplitude differences.
Subject Specialisation in Academic Libraries: some preliminary observations on role conflict and organizational stress
Authors: Guttsman W.L. 
Published: March 2008

The Library of the University of East Anglia has been organized on the basis of subject specialization, a system which the author believes to be applicable to small and medium-sized universities. A comparison of university structure and university library structure shows bow the system can bring about organizational strains and conflict situations in respect of career patterns of senior staff members. The need to recognize academic considerations for library promotions is stressed and a case made out for the fullest involvement of all senior library staff in policy-making. A revised version of a talk originally given to a meeting of the Standing Conference of National and University Libraries at Cambridge in September 1972.
A General Survey of Senior and Intermediate Staff Deployment in University Libraries
Authors: Smith G.C.K. , Schofield J.L. 
Published: March 2008

The terms of reference of the Cambridge Library Management Research Unit included a proposal for research into the staffing of university libraries. Preliminary investigations based upon a literature survey revealed a shortage of adequate current data, and suggested a need for further information. It was therefore decided to carry out a survey of staff deploy ment; this took place in April 1971. The survey involved University Librarians, a sample of professionally qualified librarians who had held university library appointments, and as many graduate staff in university libraries without library qualifications as could be traced. The ressslts give the type of establishment, the numbers of appointments and resignations in recent years, the academic qualifications of librarians, their job expectations, reasons for movement, and professional development. In each section of the investigation it is hoped that results have emerged which will usefully complement the findings of the DES survey of manpower requirements in libraries.
The Administration of Local Studies Collections in Great Britain and Northern Ireland
Authors: Nichols Harold 
Published: March 2008

This survey of local studies collections in public libraries after local government reorganization shows that there is a development towards a standard organizational structure, even though geographical considerations condition the pattern of provision, with a centralized research collection containing materials for the whole authority area, supported by duplicate and microform collections at branches for their locality. The centralized collections are currently stronger in urban areas, some becoming Local Studies Centres to include record office, museum and library functions. District collections are more developed in counties and often supply locality dossiers and school project packs. Divisional management structures have led to Local Studies Panels consisting of repre sentatives responsible for local studies at Divisional and Central levels, and this appears to stimulate planned development mainly in cooperative acquisition, microfilm programmes, indexing and current awareness services. The vital relationship between libraries and record offices has not often been improved by local government reorganization. In England and Wales in only 25% of Non- Metropolitan Counties are the library and the archives office responsible to the same com mittee, and in Metropolitan areas only the new County, not a library authority, is auto matically authorized to provide the archive service.
Uses and users of public sector business libraries: a study based on Birmingham, Manchester and Nottingham libraries
Authors: Roberts N. , Clarke D. , Craghill D. , White D. 
Published: March 2008

Some 564 interviews with users of business libraries were carried out in the central public libraries of Birmingham, Manchester and Nottingham during the period July-October 1986. In addition, during the same period, 1277 telephone calls were monitored. General characteristics of business library use are depicted in terms of work-related and personal forms of use. Motivations for use are examined. Information demands and satisfaction rates are analysed. Users' perceptions of available services are identified, together with proposals for improvements. Telephone inquiry data are categorized and related to visit data. Data relating to users' assessments of the value of business libraries are presented.
Hypothyroidism determines the clinical and immunological manifestations of Arabs with lupus
Authors: Al Saleh J , El Sayed M , Jassim V , Mohammed N , Khan N 
Published: March 2008

Abstract Data on thyroid disease in Arabs with lupus is scarce. We conducted a cross-sectional and retrospective case–control study to report the prevalence of thyroid diseases in 110 Arabs with lupus who attended our Rheumatology Clinic between January 2002 and January 2007, and to delineate the clinical and immunological features of Arabs lupus patients with thyroid diseases. We found hypothyroidism in 15 (13.7%) patients. Overall, 25.6% had elevated thyroid peroxidase antibodies, 14.6% had elevated anti-thyroglobulin antibodies, and 13.7% were positive for both antibodies. Lupus patients with hypothyroidism had a significantly higher frequency of polyarthritis (OR = 9.3, CI: 2.0–41.7, P < 0.001), cutaneous manifestations (OR = 5.6, CI: 2.4–14.3, P < 0.0001), positive anti-thyroglobulin antibodies (OR = 19.9, CI: 8.38–47.4, P < 0.0001), and thyroid peroxidase antibodies (OR = 12.3, CI: 6.27–24.1, P < 0.0001) than lupus patients with normal thyroid function. Furthermore, neuropsychiatric (OR = 0.36, CI: 0.14–0.93, P < 0.05) and hematological (OR = 0.52, CI: 0.29–0.91, P < 0.05) manifestations were significantly lower in patients with hypothyroidism than in euthyroid patients. Surprisingly, the prevalence of anticardiolipin antibody immunoglobulin G (aCL IgG) (OR = 0.34, CI: 0.13–0.86, P < 0.05), lupus anticoagulant (OR = 0.02, CI: 0.001–0.35, P < 0.0001), and anticardiolipin syndrome (OR = 0.02, CI: 0.001–0.43, P < 0.0001) were significantly lower in lupus patients with hypothyroidism than in lupus patients with normal thyroid function. In conclusion, the prevalence of hypothyroidism in Arabs with lupus is comparable to that reported in the literature. Arab lupus patients with hypothyroidism have distinctive clinical and immunological features that differentiate them from euthyroid patients.
E/E' ratio is more sensitive than E/A ratio for detection of left ventricular diastolic dysfunction in systemic lupus erythematosus
Authors: Lee S-W , Park M-C , Park Y-B , Lee S-K 
Published: March 2008

Abstract To investigate whether the ratio of mitral peak velocity of early filling (E) to early diastolic mitral annular velocity (E') (E/E' ratio) can detect left ventricular diastolic dysfunction more sensitively than the ratio of E to mitral peak velocity of late filling (A) (E/A ratio) in systemic lupus erythematosus (SLE). A total of 137 patients with SLE were investigated and compared with 110 age-matched and sex-matched controls retrospectively. Two-dimensional echocardiography and M-mode echocardiography including conventional and tissue Doppler imaging were performed. There were no differences in the left ventricle ejection fractions and the mean E/A ratio between the two groups. However, the mean E/E' ratio of patients was higher than that of the controls (10.4 ± 4.0 vs 7.7 ± 2.1, P < 0.01). Significantly higher left ventricle ejection fractions and lower E/E' ratio were found in patients with systemic lupus erythematosus receiving angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker than those not receiving ( P < 0.05). Our study showed that the E/E' ratio is more sensitive than the E/A ratio for detection of the left ventricle diastolic dysfunction. Furthermore, patients who had received angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker treatment showed significantly better preservation of both systolic and diastolic function of left ventricle in comparison with those who had not received.
Percutaneous management of chronic deep venous reflux: review of experimental work and early clinical experience with bioprosthetic valve
Authors: Pavcnik Dusan , Uchida Barry , Kaufman John , Hinds Monica , Keller Frederick S , Rösch Josef 
Published: March 2008

Abstract Lower extremity chronic deep venous insufficiency (CDVI) is common and remains a major health problem worldwide. Selected patients benefited from direct deep vein valve surgical repair or valve transplantation. A major limitation of this approach is that most of the patients are not candidates for these procedures due to obstructions or residual thrombus throughout the vein. The past 15 years have witnessed experimental efforts at catheter-based management of CDVI. This review describes the initial designs and experimental evolution of a mechanical and bioprosthetic venous valve that can be implanted by using a transcatheter technique. These valves consisted of single, double, or triple cusp leaflets made of synthetic or biological materials attached to a carrier or frame. All described devices for percutaneous transcatheter valve placement rely on some form of a vascular stent for valve attachment.
A randomized trial of iloprost in patients with intermittent claudication
Authors: Creager Mark A , Pande Reena L , Hiatt William R 
Published: March 2008

Abstract Prostanoids, which promote vasodilation and reduce platelet aggregation, have been proposed as candidate therapies for intermittent claudication due to peripheral arterial disease (PAD). However, studies of these medications have yielded inconsistent results. This study tested the hypothesis that iloprost, an oral prostacyclin analogue, would improve walking distance and quality of life in patients with intermittent claudication. The study was a multi-center, randomized, double-blind, placebo-controlled trial comparing three doses of oral iloprost (50 μg, 100 μg, or 150 μg twice daily), pentoxifylline, or placebo in 430 patients with intermittent claudication. The primary outcome measure was improvement in absolute claudication distance (ACD) after 6 months. Secondary outcomes included initial claudication distance and quality of life assessment. Placebo increased ACD by 3.3%, and iloprost increased peak ACD by 7.7%, 8.8% and 11.2% at the 50 μg, 100 μg, and 150 μg twice-daily doses, respectively (all insignificant relative to placebo). Pentoxifylline increased ACD by 13.9% relative to placebo ( p = 0.039). Neither iloprost nor pentoxifylline enhanced quality of life. These results indicate that oral iloprost is not effective in improving exercise performance or quality of life in patients with PAD who have intermittent claudication.