bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical simulations of stably stratified flow through a mountain pass
Authors: Ross A. N. , Vosper S. B. 
Published: February 2003

AbstractThe effect of boundary‐layer friction in stably stratified flow through a mountain pass is examined through a series of idealized numerical simulations. Both two‐dimensional (2‐D) simulations of flow through a valley which is infinitely long in the direction of the flow and three‐dimensional (3‐D) simulations of flow through a pass in a 2‐D ridge are conducted. For the 2‐D simulations the secondary flow induced by the flow turning in the boundary layer is investigated and the behaviour categorized depending on the location of any flow separation on the valley side. The separation (diagnosed using surface stresses) is found to depend primarily on a Froude number based on the valley depth. The generation of potential vorticity (PV) in the boundary layer adjacent to the valley sides is examined in the 2‐D simulations, and numerical results are found to agree well with simple scaling analysis.In the 3‐D case PV is still generated in the boundary layer adjacent to the sides of the pass, and this PV is advected out of the pass by the flow across the mountain. When the upstream flow is sufficiently strongly stratified (Froude number based on the mountain height less than unity) a hydraulic jump occurs on the lee side of the mountain ridge, enabling advection of the PV out of the boundary layer and into the interior of the flow. Examination of the PV structure on isentropic surfaces downwind of the mountain ridge reveals the presence of PV banners which originate from the sides of the pass. In these simulations frictional processes within the boundary layer appear to dominate the production of the PV banners, and gravity‐wave breaking plays a relatively minor role. © Royal Meteorological Society, 2003. S. B. Vosper's contribution is Crown copyright.
On the cloud processing of aerosol particles: An entraining air‐parcel model with two‐dimensional spectral cloud microphysics and a new formulation of the collection kernel
Authors: Kerkweg Astrid , Wurzler Sabine , Reisin Tamir , Bott Andreas 
Published: February 2003

AbstractA study has been made of the modification of marine aerosol particles due to cloud processes and the impact of the modified aerosols on the microphysical structure of future clouds. For this purpose, an entraining air‐parcel model with two‐dimensional spectral cloud microphysics was used. In order to treat collision/coalescence processes in the two‐dimensional microphysical module, a new realistic and continuous formulation of the collection kernel was developed. Based on experimental and theoretical data, the kernel covers the entire investigated size range of aerosols, cloud and rain drops, that is the kernel combines all important collision/coalescence processes such as the collision of cloud drops as well as the impaction scavenging of small aerosols by big raindrops. Since chemical reactions in the gas phase and in cloud drops have an important impact on the physico‐chemical properties of aerosol particles, the parcel model has been extended by a chemical module describing gas‐phase and aqueous‐phase chemical reactions. However, it is shown that in the numerical case‐studies presented in this paper the modification of aerosols by chemical reactions has a minor influence on the microphysical structure of future clouds. The production of large aerosol particles by collision/coalescence processes is mainly responsible for an enhanced formation of rain in a second cloud event. Copyright © 2003 Royal Meteorological Society
Variational assimilation of radar reflectivities in a cirrus model. I: Model description and adjoint sensitivity studies
Authors: Benedetti Angela , Stephens Graeme L. , Vukićević Tomislava 
Published: February 2003

AbstractThis paper presents an ice microphysics model to be used in variational assimilation of cloud‐radar data. The model predicts the vertical and temporal evolution of the parameters of a modified gamma size distribution describing an ice‐cloud crystal population, given an initial atmospheric state. Microphysical variables are mapped onto radar reflectivities using an explicit radar forward model. Evolution equations take into account microphysical processes relevant to ice‐crystal growth, such as vapour‐diffusion growth, aggregation, and gravitational sedimentation. The thermodynamic and dynamic state is specified from a numerical forecast or a radiosonde sounding and is assumed constant over the model integration time. Due to this assumption, the model provides no feedback to the environmental state and thus cannot be used for long‐term cloud forecasts. However, when the model is integrated over a short time interval, and the atmospheric conditions are close to water saturation at cloud levels, the model is shown to compare well with observations. An adjoint of a linearized version of the cloud model is derived and applied to investigate model sensitivities to input variables and model parameters. Results show a large sensitivity of model outputs to temperature and selected parameters related to the crystal fall‐velocity parametrization. Copyright © 2003 Royal Meteorological Society
Conditional probability seasonal predictions of precipitation
Authors: Clark Robin , Déque Michel 
Published: February 2003

AbstractUnderlying, slowly evolving sea surface temperatures (SSTs) can influence atmospheric processes on seasonal time‐scales raising hopes of producing successful seasonal forecasts using computer models. Unfortunately internal atmospheric instability and nonlinear dynamics of the atmosphere limit their skill even with perfect (ob‐served) SSTs. An approach using analogues in an ensemble environment is shown to increase the skill of seasonal forecasts by using raw model ensemble forecasts to generate enlarged analogue ensembles consisting entirely of observations from other years. These new ensembles are a cheap and effective way of producing larger ensembles, which use readily available historical information about the real atmosphere which raw models do not. Conditional probability predictions from these new ensembles are shown to have higher skill than raw model forecasts in all seasons, in all parts of the world. They are also shown to be more skilful than climatology in certain seasons, also in all regions of the world. They can also be used to aid skill prediction. Copyright © 2003 Royal Meteorological Society
The impact of upstream blocking, drainage flow and the geostrophic pressure gradient on the persistence of cold‐air pools
Authors: ZÄngl G. 
Published: February 2003

AbstractIdealized numerical simulations are performed to investigate dynamical mechanisms affecting the persistence of cold‐air pools in basins and valleys. The first orography type considered is a shallow elongated basin located upstream of a mountain ridge. For sensitivity tests, the mountain ridge is removed. The second type is a basin embedded in a plateau‐like mountain ridge. In part of the simulations, this basin has an outflow towards the lee‐side plain so as to assess the impact of the drainage flow. The large‐scale flow is taken to be in geostrophic balance. In the standard setting, it is perpendicular to the basin and the ridge.The main effect of a large‐scale pressure gradient is to induce a circulation within a cold‐air pool until the upper boundary of the cold pool is inclined such as to compensate for the ambient pressure gradient. The cold air accumulates where the ambient pressure is lowest. For a shallow basin, this means that part of the cold air may be lost due to advection out of the basin. The upstream influence of a mountain ridge in the lee of a shallow basin is found to be twofold. It tends to deflect the low‐level flow towards the lower pressure, leading to an additional ridge‐parallel force on the cold‐air pool. On the other hand, the absolute wind speed is reduced, diminishing the turbulent mixing near the top of the cold pool. The simulations show that the first effect prevails for ridge‐normal flow while second effect may dominate for other flow directions. Drainage flow out of a valley is found to be very important as it promotes the penetration of warm air into valleys very effectively. It may cause a cold pool in a deep valley to disappear more quickly than a cold pool in a shallow basin. Sensitivity tests show that the persistence of a cold pool depends on its depth, on its vertically integrated heat deficit, and on the maximum heat deficit at the bottom of the cold pool. Copyright © 2003 Royal Meteorological Society
Nasal polyps: Still more questions than answers
Authors: Bateman Neil D. , Fahy Colm , Woolford Timothy J. 
Published: February 2003

Nasal polyps are common, affecting one to four per cent of the population. Their cause, however, remains unknown and it is possible that it is not the same in all patients. They have a clear association with asthma, aspirin sensitivity and cystic fibrosis. Histologically they demonstrate large quantities of extracellular fluid, mast cell degranulation and an infiltrate of inflammatory cells, usually eosinophils. While this appearance would suggest an allergic pathology there is little conclusive evidence to support this in most patients. There is, however, some preliminary evidence to suggest that a local allergic process could be the cause. While allergic fungal sinusitis is a well defined clinical entity with recognized diagnostic criteria the ubiquitous nature of fungal spores makes the role of fungal infection in patients with nasal polyps difficult to determine and currently this remains unclear.Surgical treatment of nasal polyps has declined in recent years as the benefits of medical treatment have become increasingly recognized. There is good evidence to support the use of corticosteroids both as a primary and post-operative treatment in the majority of patients. Other medical treatments require further evaluation before they could be considered a viable alternative to steroids. Assessment of the literature regarding surgical intervention is difficult and there is little evidence on which to base a surgical treatment philosophy. The authors believe that an endoscopic approach using a microdebrider facilitates accurate removal of polyps with preservation of normal anatomy.
Treatment of Ménière’s disease by intratympanic gentamicin application
Authors: Assimakopoulos Dimitrios , Patrikakos George 
Published: February 2003

Ménière’s disease is a vestibular disorder characterized by episodic vertigo, tinnitus, fluctuant hearing loss, and ear fullness, with vertiginous attacks being the most disabling complaint. The effectiveness of conservative treatment has been variable, while surgical techniques provide more permanent relief from vertigo, but pose possible morbidity and cochlear risk. Intratympanic administration of gentamicin has been proposed as an alternative for patients with debilitating Ménière’s disease who have failed to respond to standard medical treatment. The goal of such treatment is to control vertigo by partially or completely destroying the vestibular system, while at the same time maintaining hearing.In this review we present the current medical literature on pathophysiology, pharmacokinetics, administration methods, dosage, treatment protocols, and problems related to intratympanic administration of gentamicin for patients with MD.Intratympanic gentamicin administration is a simple medical modality for treatment of persistent vertigo in patients with Ménière’s disease. According to recent world research protocols, we propose the instillation of gentamicin by transtympanic injection, as a quick, easy, well-tolerated, ambulatory and cost-effective technique. Drug solution concentrations should be dependent on the frequency, intensity and duration of vertigo spells, as well as the degree of existing hearing loss, thus providing progressive vertigo relief with a low possibility of secondary deafness.
External auditory canal duplication anomalies associated with congenital aural atresia
Authors: Blevins Nikolas H. , Byahatti Seema V. , Karmody Collin S. 
Published: February 2003

Maldevelopment of the first branchial cleft can produce a broad spectrum of anomalies in its derivative structure, the external auditory canal (EAC). Failure of the cleft to develop normally can result in either the absence of a normally patent EAC (atresia, or stenosis) or a duplication anomaly (cyst, sinus, or fistula). Despite their common origins, the coexistence of these anatomical abnormalities is quite unusual. We present four patients with both aural atresia and duplication anomalies of the EAC. Three patients had non-syndromic unilateral aural atresia and presented with periauricular lesions originating from the first branchial cleft. The other patient had a variant of Treacher Collins syndrome and presented with draining infra-auricular fistulae.The classification and management of first branchial cleft anomalies is reviewed in light of these cases. An understanding of the embryogenesis of the external ear is necessary to successfully recognize and treat this spectrum of deformities. A classification system is presented that encompasses the full spectrum of first cleft anomalies.
Voice rehabilitation after laryngectomy with the Provox® voice prosthesis in South Africa
Authors: Cornu Anne-Sophie , Vlantis Alexander C. , Elliott Haley , Gregor R. Theo 
Published: February 2003

A study was undertaken to determine whether the Provox® voice prosthesis provides good voice rehabilitation following a total laryngectomy in the urban, suburbanand rural populations served by a tertiary referral hospital in South Africa.Between 1995 and 1999, a cohort of 128 patients at Tygerberg Hospital was rehabilitated with the Provox™ voice prosthesis after laryngectomy. In 104 patients primary placement of the prosthesis was done at the time of the laryngectomy. Mean device life and adverse events were determined. Voice quality was assessed subjectively in 104 patients and objectively in 26 patients.The mean device life was 303 days and adverse events occurred in 16 patients. Subjectively, 77 of 104 patients had a good voice, and objectively 22 of 26 patients had good voice intelligibility. The Provox® voice prosthesis provides good voice rehabilitation following total laryngectomy, with minimal complications, in the population served by Tygerberg Hospital.
Epithelioid haemangioendothelioma arising in the nasal cavity
Authors: Girolamo Alberto Di , Giacomini Pier Giorgio , Coli Antonella , Castri Federica , de Padova Alessandro , Bigotti Giulio 
Published: February 2003

We report here the case of an epithelioid haemangioendothelioma (EHE) arising in the nasal cavity which is, to the best of our knowledge, the first ever described example in the world literature in that particular site.The patient is a 23-year-old male who presented with repeated episodes of epistaxis from the nasal cavity and with a 1.5 cm reddish, polypoid, smooth, spontaneously bleeding nodule in the rightmiddle meatus. This lesion was histologically diagnosed as epithelioid haemangioendothelioma. Immunohistochemically the neoplasm displayed striking positivity for CD31, CD34 and vimentin. A surgical approach was performed by ’facial degloving’, removing the right inferior turbinate, the anterior two-thirds of the middle turbinate and the medial wall of the ethmoid bone. After 12 months follow-up the patient is disease-free, without any local or distant recurrence.
Tissue augmentation using Bioplastique® as a treatment of leakage around a Provox® 2 voice prosthesis
Authors: Rokade A. V. , Mathews J. , Reddy K. T .V. 
Published: February 2003

Rehabilitation of voice and speech after laryngectomy with valve prosthesis has become a well-established practice in recent years. The formation of tracheo-oesophageal fistula (TOF) and the subsequent management of the patient with a voice prosthesis can be associated with a number of problems and complications.We report a new technique of the use of injectable Bioplastique® in the treatment of persistent leakage around Provox® 2 voice prosthesis. Our experience in two cases has shown that it is a relatively simple and effective procedure in stopping the leak around the valve immediately and is without any short-term complications.
Laser Shadow Analysis of Particle-Size Distribution of Montmorillonites in Aqueous Suspensions
Authors: Yariv S. , Lapides I. 
Published: February 2003

AbstractParticle-size analysis (obtained by Galai CIS 1) was used to determine the following statistical parameters of aqueous suspensions of Na-, Ca- and Mn-montmorillonite: the size distributions, the diameters of the largest and of the median and mean particles, and the percentage of particles with diameters <1.5 µm. Dilution or shaking had almost no effect on the particle-size distribution curves and statistical parameters of Ca- and Mn-montmorillonites but the curves and the statistical parameters of Na-montmorillonite were very much affected by these treatments. The median and mean diameters of Na-montmorillonite range from 0.8 to 10.5 µm and 0.8 to 11.6 µm, respectively, the median and mean diameters of Ca-montmorillonite range from 1.5 to 3.6 µm and 2.12 to 4.2 µm, respectively, and those for Mn-montmorillonite from 1.2 to 2.3 µm and 1.5 to 2.5 µm, respectively. The presence of large particles of Na-montmorillonite was attributed to the extensive swelling of this clay in aqueous suspensions by osmotic water adsorption. The median and mean diameters of aged Na-montmorillonite suspensions indicate that swelling increases with dilution. The swelling of Ca- and Mn-montmorillonite, on the other hand, is limited and their particle size does not increase with dilution.
Firefighting and risk of testicular cancer: Results from a German population‐based case‐control study
Authors: Stang Andreas , Jöckel Karl‐Heinz , Baumgardt‐Elms Cornelia , Ahrens Wolfgang 
Published: February 2003

AbstractBackgroundThere is some evidence of an elevated risk for testicular cancer among firefighters.MethodsWe performed a population‐based case–control study including 269 testicular cancer cases and 797 controls matching on age and region with a special focus on occupational exposures. Job tasks were coded according to the International Standard Classification of Occupations (ISCO 68). We used conditional logistic regression to calculate odds ratios (OR).ResultsThree controls (0.4%) and four cases (1.5%) ever worked as firefighters. Firefighters showed an increased odds of testicular cancer in the matched evaluation (OR = 4.3, 95% confidence interval (95% CI) 0.7–30.5). The adjustment for a history of cryptorchidism or family history of testicular cancer did not alter our results.ConclusionAlthough the association between firefighting and testicular cancer risk is based on only small numbers of exposed subjects in our study, the finding is consistent with a recent cohort study from New Zealand. Occupational hazards experienced by firefighters may increase the risk of testicular cancer. Am. J. Ind. Med. 43:291–294, 2003. © 2003 Wiley‐Liss, Inc.
Role of underlying pulmonary obstruction in short‐term airway response to metal working fluid exposure: A reanalysis
Authors: Zeka Ariana , Kriebel David , Kennedy Susan M. , Wegman David H. 
Published: February 2003

AbstractBackgroundAmong epidemiologic studies that found evidence for associations between exposures to metal working fluids (MWF) and pulmonary function impairments, one found effects restricted to workers with fixed obstruction at baseline. We reanalyzed a previously published study on MWF exposure and cross‐shift pulmonary function to further evaluate this finding.MethodsPulmonary function was measured cross‐shift on Monday and Friday in 131 male automotive workers. Quantitative personal MWF exposure data were available. Those with an FEV1/FVC ratio of ≤0.72 were considered obstructed.ResultsThere was a trend towards increasing incidence of cross‐shift decrement in FEV1 as MWF exposure increased in the full cohort as well as when the results were restricted to the 19 (14.5%) who were obstructed. Those with obstruction were slightly more likely to show decrements in FEV1 on Fridays. Removing the obstructed subgroup did not appear to substantially weaken the exposure–response relation.ConclusionsNo important differences were found in cross‐shift effects of MWF between obstructed and non‐obstructed workers. Am. J. Ind. Med. 43:286–290, 2003. © 2003 Wiley‐Liss, Inc.
Using respirators and goggles to control exposure to air pollutants in an anatomy laboratory
Authors: Akbar‐Khanzadeh Farhang , Pulido Edgar V. 
Published: February 2003

AbstractBackgroundEngineering or administrative methods are often insufficient or impractical to control exposure to chemicals in anatomy laboratories. This study explored the feasibility of wearing one or a combination of respirators and goggles used as personal protective equipment (PPE) to control exposure in one such laboratory.MethodsA group of 28 subjects were briefly trained in wearing PPE, fit‐tested, and asked to complete a questionnaire regarding their subjective reaction after wearing the assigned PPE ensemble while working in the laboratory. The subjects' exposure to formaldehyde was also measured and generally exceeded the recommended limits.ResultsWhen a full‐face respirator or the combination of a half‐mask respirator and goggles was worn, a majority of subjects reported no odor problem and no irritation to eyes or upper respiratory system. Subjects accepted the PPE to certain degrees, but those using respirators encountered difficulties communicating with others.ConclusionsThe combination of a half‐mask respirator and goggles was the most feasible ensemble to control exposure to air pollutants in an anatomy laboratory. Am. J. Ind. Med. 43:326–331, 2003. © 2003 Wiley‐Liss, Inc.
Cancer mortality in a cohort of male German iron foundry workers
Authors: Adzersen Karl‐Heinrich , Becker Nikolaus , Steindorf Karen , Frentzel‐Beyme Rainer 
Published: February 2003

AbstractBackgroundObservations of an increased incidence of cancers of the upper aero‐digestive tract (pharynx, esophagus, larynx, lung) among workers of local German foundries gave rise to concern about a potentially elevated occupational risk of those cancer sites. The purpose of the study was to examine whether occupational exposure in iron foundries increases the risk of cancer.MethodsA historical cohort study of 17,708 male German production workers in 37 iron foundries who were first employed in 1950–1985 with a minimum employment period of 1 year was initiated. Employment and occupational histories were collected. Mortality was compared with that of the German general population during 1950–1993 using a new method for computing the SMR when not all causes of death are available (called SMR*).ResultsMortality from all causes was elevated to SMR = 115.4 (95% confidence interval (CI) = 111.9–119.1), as was for total cancer (SMR* = 123.8, CI = 102.1–152.6), especially cancers of the lung (SMR* = 163.9, CI = 123.9–223.0) and liver (SMR* = 322.5, CI = 149.5–844.8), and diseases of the respiratory system (SMR* = 147.6, CI = 100.4–221.5). Non‐significant elevations of mortality were also found for cancers of the mouth and pharynx (SMR* = 153.5, CI = 82.3–359.8) and larynx (SMR* = 173.1, CI = 85.5–550.5). Mortality from various causes of death was higher among workers with shorter exposure periods than among long‐term employees. The elevated mortality persisted for years and decades after termination of employment.ConclusionsThe results provide further evidence for an increased risk of lung cancer and possibly other cancers of the upper aero‐digestive tract among foundry workers. Special attention should be paid to the strongly increased mortality from liver cancer and the mortality pattern among employees having terminated work. Am. J. Ind. Med. 43:295–305, 2003. © 2003 Wiley‐Liss, Inc.