bluuebunny/crossref_metadata_2025 huggingface dataset:
Gaussian envelope for 3D geomagnetic data inversion
Authors: Tontini Fabio Caratori , Faggioni Osvaldo , Beverini Nicolò , Carmisciano Cosmo
Published: May 2003

We describe an inversion method for 3D geomagnetic data based on approximation of the source distribution by means of positive constrained Gaussian functions. In this way, smoothness and positivity are automatically imposed on the source without any subjective input from the user apart from selecting the number of functions to use. The algorithm has been tested with synthetic data in order to resolve sources at very different depths, using data from one measurement plane only.

The forward modeling is based on prismatic cell parameterization, but the algebraic nonuniqueness is reduced because a relationship among the cells, expressed by the Gaussian envelope, is assumed to describe the spatial variation of the source distribution.

We assume that there is no remanent magnetization and that the magnetic data are produced by induced magnetization only, neglecting any demagnetization effects. The algorithm proceeds by minimization of a χ2misfit function between real and predicted data using a nonlinear Levenberg‐Marquardt iteration scheme, easily implemented on a desktop PC, without any additional regularization. We demonstrate the robustness and utility of the method using synthetic data corrupted by pseudorandom generated noise and a real field data set.
Identifying, removing, and imaging P‐S conversions at salt‐sediment interfaces
Authors: Lu Richard S. , Willen Dennis E. , Watson Ian A.
Published: May 2003

The large velocity contrast between salt and the surrounding sediments generates strong conversions between P‐ and S‐wave energy. The resulting converted events can be noise on P‐wave migrated images and should be identified and removed to facilitate interpretation. On the other hand, they can also be used to image a salt body and its adjacent sediments when the P‐wave image is inadequate. The converted waves with smaller reflection and transmission angles and much larger critical angles generate substantially different illumination than does the P‐wave.

In areas where time migration is valid, the ratio between salt thickness in time and the time interval between the P‐wave and the converted‐wave salt base on a time‐migrated image is about 2.6 or 1.3, depending upon whether the seismic wave propagates along one or both of the downgoing and upcoming raypaths in salt as the S‐wave, respectively. These ratios can be used together with forward seismic modeling and 2D prestack depth migration to identify the converted‐wave base‐of‐salt (BOS) events in time and depth and to correctly interpret the subsalt sediments. It is possible to mute converted‐wave events from prestack traces according to their computed arrival times. Prestack depth migration of the muted data extends the updip continuation of subsalt sedimentary beds, and improves the salt–sediment terminations in the P‐wave image. Prestack and poststack depth‐migrated examples illustrate that the P‐wave and the three modes of converted waves preferentially image different parts of the base of salt. In some areas, the P‐wave BOS can be very weak, obscured by noise, or completely absent. Converted‐wave imaging complements P‐wave imaging in delineating the BOS for velocity model building.
Angle‐domain common‐image gathers by wavefield continuation methods
Authors: Sava Paul C. , Fomel Sergey
Published: May 2003

Migration in the angle domain creates seismic images for different reflection angles. We present a method for computing angle‐domain common‐image gathers from seismic images obtained by depth migration using wave‐field continuation. Our method operates on prestack migrated images and produces the output as a function of the reflection angle, not as a function of offset ray parameter as in other alternative approaches. The method amounts to a radial‐trace transform in the Fourier domain and is equivalent to a slant stack in the space domain. We obtain the angle gathers using a stretch technique that enables us to impose smoothness through regularization. Several examples show that our method is accurate, fast, robust, and easy to implement. The main anticipated applications of our method are in the areas of migration‐velocity analysis and amplitude‐versus‐angle analysis.
Linearization of the P‐wave eikonal equation for weak vertical transverse isotropy
Authors: Schneider William A.
Published: May 2003

I develop approximate P‐wave and SV‐wave eikonal equations for weak vertical transversely isotropic (VTI) media and then use perturbation theory to solve the P‐wave eikonal equation. I proceed by expressing the exact VTI eikonal equations for P‐waves and SV‐waves in terms of the intuitive “Thomsen” anisotropy parameters and then linearizing the results with respect to these parameters. Next, I apply perturbation theory (with a heterogeneous, isotropic “reference” medium) to the P‐wave weak VTI eikonal equation. This results in a linear partial differential equation for the traveltime perturbation, which I solve analytically along raypaths in the isotropic reference medium. Traveltimes in the weak VTI medium may then be obtained by simply integrating the reference slowness function plus the (weighted) anisotropy perturbations along raypaths in the isotropic reference medium. This simple solution may be incorporated into standard isotropic ray tracing or traveltime generation methods to produce traveltimes for weak VTI media. I analytically incorporated the method into an isotropic eikonal equation solver and tested it on a vertically heterogeneous weak VTI model, where the strength of the anisotropy was 5–15%. Comparison against results from an exact VTI ray tracing code showed that, for lateral distances up to twice the depth, the weak VTI traveltimes and phase angles were accurate to within 1.3% and 2.2%, respectively. This linear theory yields a physical understanding for how the anisotropy parameters cause traveltimes in VTI media to differ from those in isotropic media. Applications of the theory also include traveltime computation and insights into linear tomographic velocity estimation of reflection seismic data in weak VTI media.
Cancellation of multiple harmonic noise series in geophysical records
Authors: Butler Karl E. , Russell R. Don
Published: May 2003

We describe a procedure for the simultaneous estimation of multiple stationary sinusoidal contaminants in a time series and demonstrate its application to the cancellation of powerline noise in seismic and seismoelectric records. An estimate of the noise in each record is obtained by seeking a linear combination of sinusoids that are harmonics of one or more fundamental frequencies; this combination must fit the data in a least‐squares sense. The algorithm accommodates estimation windows of arbitrary length, including windows shorter than one fundamental period, without cross‐contamination between harmonic estimates.

Provision is made for refining the fundamental frequencies, for which small errors (e.g., 0.01 Hz in 60 Hz) can result in significant residual noise near the ends of the record (beating). Our strategy is novel in that it uses all specified harmonics and iteratively searches frequency space for a best fit using numerical derivatives. This determination is very robust for at least two fundamentals (the limit of our investigation) and often converges rapidly to three or four decimal places.

Cancellation of harmonic noise has been essential in our research to uncover seismoelectric signals that are often completely masked by powerline noise. We expect this procedure will be useful in other geophysical methods—especially exploration seismology, for which powerline contamination is a recognized problem.
Adaptive decomposition of multicomponent ocean‐bottom seismic data into downgoing and upgoing P‐ and S‐waves
Authors: Schalkwijk K. M. , Wapenaar C. P. A. , Verschuur D. J.
Published: May 2003

With wavefield decomposition, the recorded wavefield at a certain depth level can be separated into upgoing and downgoing wavefields as well as into P‐ and S‐waves. The medium parameters at the considered depth level (e.g., just below the ocean‐bottom) need to be known in order to be able to do a decomposition. In general, these parameters are unknown and, in addition, measurement‐related issues, such as geophone coupling and crosstalk between the different components, need to be dealt with. In order to apply decomposition to field data, an adaptive five‐stage decomposition scheme was developed in which these issues are addressed.

In this study, the adaptive decomposition scheme is tested on a data example with a relatively shallow water depth (∼120 m), consisting recordings from of a full line of ocean‐bottom receivers. Although some of the individual stages in the decomposition scheme are more difficult to apply because of stronger interference between events compared to data acquired over deeper water, the end result is satisfying. Also, a good decomposition result is obtained for the S‐waves. The extension of the decomposition scheme to a complete line of ocean‐bottom cable data consists of a repeated application of the procedure for each receiver. The resulting decomposed upgoing P‐ and S‐wavefields are processed, yielding poststack time migrated images of the subsurface. Comparison with the images obtained from the original (i.e., not decomposed) measurements shows that wavefield decomposition just below the ocean bottom leads to a strong attenuation of multiply reflected events at the sea surface and better event definition in both P‐ and S‐wave sections. Other decomposition effects like improved angle‐dependent amplitudes cannot be evaluated in this way.
A test for measuring syntactic development in young children
Authors: Schlichting J. E.P.T. (Liesbeth) , Spelberg Henk C. Lutje
Published: May 2003

This article concerns linguistic, psychometric and clinical aspects of the Test for Sentence Development, a subtest of a new Dutch language production battery, the Schlichting Test voor Taalproductie (Schlichting Test for Language Production). The purpose of the Test for Sentence Development is to assess the syntactic knowledge in the language production of young Dutch children. The Test for Sentence Development aims to give an index of the level of grammatical skills of children from 1;8 to 6;3 and makes use of functional imitation as an elicitation technique. The advantage of the new test is that very young children can be assessed systematically, which was not possible previously. In the standardization study, the tests were administered to a representative sample of 1049 Dutch children. The reliability and validity results justify the use of the test in clinical settings and language research.
Comparability of a paper-based language test and a computer-based language test
Authors: Choi Inn-Chull , Kim Kyoung Sung , Boo Jaeyool
Published: May 2003

With the advent of the digital revolution, language testers have endeavored to utilize state-of-the-art computer technology to satisfy the ever-growing need for a tool to measure English communication skills with maximal accuracy and efficiency. Thanks to the concerted efforts made by experts in such fields as computational linguistics, computer engineering, computer-assisted language learning, and psychometrics, language testers have recently succeeded in developing computer/web-based language tests. Among them are the TOEFL CBT by Educational Testing Service and CommuniCAT by the University of Cambridge Local Examinations Syndicate. As with the paper-based language test (PBLT), more rigorous research is now being conducted on the validity of computer-based language tests (CBLT) and computer adaptive language tests (CALT). Content analyses and comparability studies of PBLT and CBLT/CALT are prerequisites to such validation research. In this context, utilizing an EFL test battery entitled the Test of English Proficiency developed by Seoul National University (TEPS), the present study is aimed at addressing the issue of the comparability between PBLT and CBLT based on content and construct validation employing content analyses based on corpus linguistic techniques in addition to such statistical analyses as correlational analyses, ANOVA, and confirmatory factor analyses. The findings support comparability between the CBLT version and the PBLT version of the TEPS subtests (listening comprehension, grammar, vocabulary, and reading comprehension) in question.
Task difficulty in speaking tests
Authors: Fulcher Glenn , Reiter Rosina Márquez
Published: May 2003

The difficulty of speaking tasks has only recently become a topic of investigation in language testing. This has been prompted by work on discourse variability in second language acquisition (SLA) research, new classificatory systems for describing tasks, and the advent of statistical techniques that enable the prediction of task difficulty. This article reviews assumptions underlying approaches to research into speaking task difficulty and questions the view that test scores always vary with task conditions or discourse variation. A new approach to defining task difficulty in terms of the interaction between pragmatic task features and first language (L1) cultural background is offered, and the results of a study to investigate the impact of these variables on test scores are presented. The relevance for the generalizability of score meaning and the definition of constructs in speaking tests is discussed.
Meeting need and achieving sustainability in water project interventions
Authors: Huby Meg , Stevenson Stuart
Published: June 2003

This paper reviews common reasons postulated for the failure of many externally funded projects to improve the water supplies of people in poor rural areas of developing countries. Analysis of survey data from Tanzania shows that villages most in need of water supply improvements are unlikely to benefit from short-term interventions based on ‘dig-install-depart’ models. Excess availability and low value placed on labour in poor village communities reduce the chances that necessary effort and resources will be deployed to maintain water schemes following the withdrawal of funding agencies. The paper concludes that, to reduce poverty, interventions must be accompanied by broader packages of prolonged support, enabling communities to develop the skills and obtain the means to maintain improvements in the long term.
Land tenure reform in Africa: a shift to the defensive
Authors: Smith Robert E.
Published: June 2003

Land tenure reform has been advocated as an instrument of development in sub-Saharan Africa since before Independence, based on a neoclassical economic model promising greater agricultural productivity as a result of titling. This in turn, it was suggested, would promote land investments, credit supply and efficient land markets. Titling policies were justified in the 1980s by evidence from southeast Asia, particularly Thailand. However, empirical studies in Africa have largely failed to find any of the promised positive effects; indeed they have revealed negative effects of titling policies, especially by worsening the tenure insecurity of poor farmers whom such policies should have helped. In the last decade the discourse of land tenure reform in Africa has departed from promises of increased incomes and shifted to a conservative, defensive stance, focused on preserving livelihoods against élite predation. This paper explores why the neoclassical model has not borne fruit in sub-Saharan Africa, describes inherent weaknesses in the model as applied to the African context and suggests methods by which the model could be better tested before dismissing entirely the use of tenure reform as an instrument against poverty.
Extensions of the Bartlett-Lewis model for rainfall processes
Authors: Salim Agus , Pawitan Yudi
Published: June 2003

While the Bartlett-Lewis model has been widely used for modelling rainfall processes at a fixed point in space over time, there are observed features, such as longer-scale dependence, which are not well fitted by the model. In this paper, we study an extension where we put an extra layer in the clustered Poisson process of storm origins. We also investigate the Pareto inter-arrival time for the storm origins, which has been used to model web-traffic data. We derive the theoretical first and second-order properties of the multi-layer clustered Poisson processes, but generally we have to rely on Monte Carlo techniques. The models are fitted to hourly rainfall data from Valentia observatory in southwest Ireland, where the extensions are shown to improve on the standard models. We generalize these models further by allowing some parameters of the models to be a function of some covariates. An application using data from Valentia observatory and Belmullet shows how to use this class of models to analyze the association between the rainfall pattern and the North Atlantic Oscillation (NAO) index.
Likelihood-based analysis of longitudinal count data using a generalized Poisson model
Authors: Toscas Peter J , Faddy Malcolm J
Published: June 2003

Models based on a generalization of the simple Poisson process are discussed and illustrated with an analysis of some longitudinal count data on frequencies of epileptic fits. The models enable a broad class of discrete distributions to be constructed, which cover a variety of dispersion properties that can be characterized in an intuitive and appealing way by a simple parameterization. This class includes the Poisson and negative binomial distributions as well as other distributions with greater dispersion than Poisson, and also distributions underdispersed relative to the Poisson distribution. Comparing a number of analyses of the data shows that some covariates have a more significant effect using this modelling than from using mixed Poisson models. It is argued that this could be due to the mixed Poisson models used in the other analyses not providing an appropriate description of the residual variation, with the greater flexibility of the generalized Poisson modelling generally enabling more critical assessment of covariate effects than more standard mixed Poisson modelling.
Use of fractional polynomials for dose-response modelling and quantitative risk assessment in developmental toxicity studies
Authors: Faes Christel , Geys Helena , Aerts Marc , Molenberghs Geert
Published: June 2003

Developmental toxicity studies are designed to assess the potential adverse effects of an exposure on developing fetuses. Safe dose levels can be determined using dose-response modelling. To this end, it is important to investigate the effect of misspecifying the dose-response model on the safe dose. Since classical polynomial predictors are often of poor quality, there is a clear need for alternative specifications of the predictors, such as fractional polynomials. By means of simulations, we will show how fractional polynomial predictors may resolve possible model misspecifications and may thus yield more reliable estimates of the benchmark doses.
Multilevel ordinal models for examination grades
Authors: Fielding Antony , Yang Min , Goldstein Harvey
Published: June 2003

In multilevel situations graded category responses are often converted to points scores and linear models for continuous normal responses fitted. This is particularly prevalent in educational research. Generalized multilevel ordinal models for response categories are developed and contrasted in some respects with these normal models. Attention is given to the analysis of a large database of the General Certificate of Education Advanced Level examinations in England and Wales. Ordinal models appear to have advantages in facilitating the study of institutional differences in more detail. Of particular importance is the flexibility offered by logit models with nonproportionally changing odds. Examples are given of the richer contrasts of institutional and subgroup differences that may be evaluated. Appropriate widely available software for this approach is also discussed.
Tapering off long-term benzodiazepine use with or without group cognitive-behavioural therapy: three-condition, randomised controlled trial
Authors: Voshaar Richard C. Oude , Gorgels Wim J. M. J. , Mol Audrey J. J. , Van Balkom Anton J. L. M. , Van De Lisdonk Eloy H. , Breteler Marinus H. M. , Van Den Hoogen J. M. , Zitman Frans G.
Published: June 2003

Background

Benzodiazepine withdrawal programmes have never been experimentally compared with a nonintervention control condition.

Aims

To evaluate the efficacy and feasibility of tapering off long-term benzodiazepine use in general practice, and to evaluate the value of additional group cognitive–behavioural therapy (CBT).

Method

A 3-month randomised, controlled trial was conducted in which 180 people attempting to discontinue long-term benzodiazepine use were assigned to tapering off plus group CBT, tapering off alone or usual care.

Results

Tapering off led to a significantly higher proportion of successful discontinuations than usual care (62% v. 21%). Adding group CBT did not increase the success rate (58% v. 62%). Neither successful discontinuation nor intervention type affected psychological functioning. Both tapering strategies showed good feasibility in general practice.

Conclusions

Tapering off is a feasible and effective way of discontinuing long-term benzodiazepine use in general practice. The addition of group CBT is of limited value.
Continuation of clozapine treatment: practice makes perfect
Authors: Whiskey Eromona , Wykes Til , Duncan-McConnell Denise , Haworth Elke , Walsh Nick , Hastilow Sarah
Published: June 2003

Aims and Method

The study aimed to identify the predictors of drop-out from clozapine treatment by examining the demographic and clinical characteristics of patients registered on clozapine within a 6-month period in one NHS Trust.

Results

During the study period, 54 patients were registered and began clozapine treatment and 31% had discontinued within 6 months. Two people died and the remainder discontinued because of non-compliance or side-effects, including neutropenia. Two factors were predictive: the age of the patient (older patients were more likely to discontinue) and the hospital where the initial registration was made.

Clinical Implications

Neither ethnicity, previous registration nor the individual prescriber are a bar to successful persistence with clozapine. However, one set of hospitals with a history of evidence-based practice and high clozapine prescribing was more successful in retaining patients on maintenance treatment. Although specific data are needed to identify more subtle contributing factors to continuation, it is clear that there is scope for improving the rate of persistence with clozapine treatment.
Development of Croydon's Primary Care Protocols for Common Mental Illnesses 2001: a bottom-up approach
Authors: Bruce Maggie
Published: June 2003

The Mental Health National Service Framework (NSF) states that primary care groups (PCGs) should work with primary care teams and specialist services to agree protocols for common mental health problems. The Primary Care Protocols for Common Mental Illnesses developed in Croydon were circulated by the Department of Health to all regional offices, as an example of good practice, and 20 health authorities and primary care organisations have requested final electronic versions to adapt for local use. The protocol dealing with eating disorders has been adapted by the Royal College of Psychiatrists Eating Disorders Special Interest Group and appears on the College's website. This paper describes how all the protocols were developed and how they can be accessed.
The Dualeh Regulations
Authors: Lucas Richard
Published: June 2003

The Government has recently added an amendment to the section of the Disability Living Allowance and Disability Working Allowance Act 1991 relating to lower rate mobility. For the first time, a differentiation has been made in the approach to assessment between those with severe mental disability, from those with severe physical disabilities. The amendment has become known as the Dualeh Regulation. The background history is described and the wider implications considered. The lower rate mobility component (LRMC) of the living allowance, currently at £14.90 a week, is for people who can walk but because of severe mental or physical disabilities need guidance or supervision from another person when walking outdoors in unfamiliar places. It is to this section of the Act that the amendments were added.
Computed tomography in suppurative ear disease: does it influence management?
Authors: Banerjee A. , Flood L. M. , Yates P. , Clifford K.
Published: June 2003

The value of high resolution computerized tomography (CT) prior to routine mastoid surgery for cholesteatoma remains controversial. Doubts about sensitivity and specificity, in detecting the extent of underlying pathology and in predicting asymptomatic complications, prevent widespread adoption.

This retrospective study looks at the influence of pre-operative scanning on the surgical management of chronic suppurative otitis media over an 18-month period. The radiological findings determined the choice of surgical approach, but contributed less to the decision to operate and the prediction of potential hazards. CT is of most value when the otologist can be flexible in surgical technique, tailoring it to imaging findings.
Intratympanic gentamicin for Ménière’s disease; a survey of current UK practice
Authors: Obholzer R. J. , Wareing M. J.
Published: June 2003

Intratympanic gentamicin is increasingly used in the treatment of Ménière’s disease. Many protocols have been published for its use, but there is little difference in outcome between them. The goal of the study was therefore to assess current UK practice in the use of intratympanic gentamicin.

A postal and e-mail survey of consultant ENT surgeons in the UK was conducted. Of 34 consultants who regularly used intratympanic gentamicin, 21 used a protocol based upon a single intratympanic dose of gentamicin via a needle through the tympanic membrane and repeated after at least a week. The remaining 13 used either a regime of more frequent administration or attempted a more complicated route of delivery in an effort to improve reliability and selectivity of action.

In the absence of evidence demonstrating benefit from regimens of increased complexity the majority of consultants are using the simplest possible protocol.
External rhinoplasty: a critical analysis of 500 cases
Authors: Foda Hossam M. T.
Published: June 2003

The study presents a comprehensive statistical analysis of a series of 500 consecutive rhinoplasties of which 380 (76 per cent) were primary and 120 (24 per cent) were secondary cases. All cases were operated upon using the external rhinoplasty technique; simultaneous septal surgery was performed in 350 (70 per cent) of the cases. Deformities of the upper two-thirds of the nose that occurred significantly more in the secondary cases included; dorsal saddling, dorsal irregularities, valve collapse, open roof and pollybeak deformities. In the lower third of the nose; secondary cases showed significantly higher incidences of depressed tip, tip over-rotation, tip asymmetry, retracted columella, and alar notching. Suturing techniques were used significantly more in primary cases, while in secondary cases grafting techniques wereused significantly more. The complications encountered intra-operatively included; septal flap tears (2.8 per cent) and alar cartilage injury (1.8 per cent), while post-operative complications included; nasal trauma (one per cent), epistaxis (two per cent), infection (2.4 per cent), prolonged oedema (17 per cent), and nasal obstruction (0.8 per cent). The overall patient satisfaction rate was 95.6 per cent and the transcolumellar scar was found to be unacceptable in only 0.8 per cent of the patients.
Measurement and validation of the voice handicap index in voice-disordered patients in Taiwan
Authors: Hsiung Ming-Wang , Lu Pai , Kang Bor-Hwang , Wang Hsing-Won
Published: June 2003

Voice disorders can cause problems for patients emotionally, physically, economically and functionally. Neither subjective nor objective voice examinations are able to evaluate such factors adequately. For this study, a retrospective analysis of 79 dysphonic cases was conducted using the voice handicap index (VHI) to gather comprehensive data across a variety of voice disorders. Of the 79 cases, 41 involved glottic insufficiency, 26 involved vocal polyps or mass, and 12 involved functional voice disorders. Cases were assessed with the VHI using physical (P), functional (F), emotional (E) parameters and a total (T) of the three. P, F, E and T variables were entered into a statistical programme and analysed using one-way analysis of variance (ANOVA). Mean ±SE values for P, F, E and T, respectively, in glottic insufficiency cases were 31.61 ± 1.10, 26.49 ± 1.43, 26.06 ± 1.54, and 84.20 ± 4.21. Mean ±SE values for P, F, E and T, respectively, in vocal mass cases were 30.69 ± 1.73, 25.23 ± 1.90, 23.96 ± 1.82, and 79.88 ± 5.08. The mean ±SE values of P, F, E and T,respectively, in functional voice disorders were 20.92 ± 2.06, 18.33 ± 1.82, 16.83 ± 1.86, and 56.08 ± 5.23. We found the mean glottic insufficiency was significantly greater than functional voice disorders for each measure. There were significant differences between vocal mass and functional voice disorders means for P and T. Glottic insufficiency and vocal mass means were not significantly different for any measure. Problems in the physical realm were identified as the most severe amongst all patients. Glottic insufficiency patients were found to suffer the most in every VHI value. Although VHI is a relatively new method by which to measure discomfort in voice-disordered patients, it provides a mechanism for patients to define their discomfort and for therapists to better target recovery programmes to patient’s needs.
Genioglossus advancement and hyoid myotomy: short-term and long-term results
Authors: Neruntarat C.
Published: June 2003

Successful results of genioglossus advancement and hyoid myotomy with suspension (GAHM) in the treatment of obstructive sleep apnoea (OSA) have been reported. However, there have been few studies of long-term results. Forty-six patients with hypopharyngeal obstruction underwent GAHM. Patients had a mean age of 40.1 ± 4.2 years and a mean body mass index (BMI) of 28.9 ± 2.1 kg/m2. The mean follow-up was 39.4 ± 5.7 monthswith a range of 37 to 46 months. The mean pre-operative RDI, short-term RDI, and long-term RDI were 47.9 ± 8.4, 14.2 ± 3.9, 18.6 ± 4.1, respectively. The mean post-operative LSAT, short-term LSAT, and long-term LSAT were 81.2 per cent ± 2.9 per cent, 88.8 per cent ± 2.7 per cent and 87.2 per cent ± 3.1 per cent, respectively. The changein BMI was significantly different in the patients with, and without, recurrence (2.1 ± 0.3 vs 0.4 ± 0.2.kg/m2, <0.05). Thirty (65.2 per cent) patientshad long-term clinical success, and six (16.7 per cent) patients with short-term success failedlong-term. GAHM appears to be an effective procedure and results in long-term success. However,patients with weight gain are at risk of recurrence.
A middle-ear simulator for practicing prosthesis placement for otosclerosis surgery using ward-based materials
Authors: Owa A. O. , Gbejuade H. O. , Giddings C.
Published: June 2003

Complications following stapedectomy are the most common cause of litigation involving otological cases in the USA. Manipulation and placement of the prosthesis during a stapedectomy may have a profound effect on the final hearing results. Concerns have been raised over the reduced number of cases, training of residents, and the maintenance of the necessary skills to achieve consistently good results.

Temporal bone dissection is an important adjunct to developing the required skills to perform stapedectomies. However the reduced availability of specimens limits their use for teaching or practising the procedure.

In order to circumvent these problems an inexpensive and easily constructed middle-ear simulator has been developed based on materials readily available in any ENT ward. It is believed that this might help trainees develop the necessary skills to master the procedure.
Foreign body reaction to an oil-based ointment: a cause of persistent otorrhoea following mastoid surgery
Authors: Mace A. T. M. , Marshall J. N.
Published: June 2003

Foreign body reactions and myospherulosis are rare complications of using oil-based ointments in otological surgery. A case of persistent otorrhoea following mastoid surgery is presented. Histology showed a foreign body reaction, with some features of myospherulosis.
A small vestibular schwannoma arising from the inferior vestibular nerve
Authors: Baguley D. M. , Jones S. E. M. , Moffat D. A.
Published: June 2003

The investigation of a complaint of unilateral right sensorineural hearing loss led to the identification of a right 3 mm vestibular schwannoma arising from the inferior division of the right vestibular nerve. On investigation the patient was found to have normal caloric function, this being mediated by the superior vestibular nerve. Both transient and distortion product otoacoustic emissions were absent in the right ear, and ABR was abnormal on this side. These findings are of interest as they indicate that this small lesion produced a hearingloss that was both cochlear and retrocochlear. The anatomical finding that the medial auditory efferents run within the inferior vestibular nerve is considered. This patient did not experience tinnitus or hyperacusis despite the site of the lesion arising from the inferior vestibular nerve.
Rhabdomyoma of the base of the tongue
Authors: Fukuda Yutaka , Okamura Hiro-Oki , Nemoto Tetsuo , Kishimoto Seiji
Published: June 2003

The histopathological and imaging findings of a rhabdomyoma of the base of the tongue were studied. An immunohistochemical examination of the tumour cells showed positiveimmunostaining for myoglobin, desmin, and striated muscle actin, but negative immunostaining for smooth muscle actin. Electron microscopy showed many glycogen granules and mitochondria in the tumour cells. The T2-weighted and contrast-enhanced magnetic resonance images (MRI) clearly delineated morphological features of this tumour, but T1-weighted MRI and computed tomography (CT) images showed no important features. These findings are typical for an adult extracardiac rhabdomyoma located in the head and neck region, and they will be useful for diagnosis of this tumour.
An undescribed first branchial cleft anomaly
Authors: Rockey Jason Gabriel , John D. Gareth , Herbetko John
Published: June 2003

A variant of a type 2 first branchial cleft anomaly, in which accessory ossicles were found, is described. There follows a discussion of the classification of first branchial cleft abnormalities and how this particular case falls outside the standard classification. CT scanning is mentioned as the investigation that is most useful for defining these abnormalities.
Facial nerve paralysis secondary to Warthin’s tumour of the parotid gland
Authors: Marioni Gino , de Filippis Cosimo , Gaio Elena , Iaderosa Gaetano Antonio , Staffieri Alberto
Published: June 2003

Facial nerve paralysis associated with a parotid gland tumour classically denotes malignancy. Only a few case reports have indicated benign parotid tumours as a cause of facial nerve palsy. We present a new case of facial nerve paralysis secondary to Warthin’s tumour of the parotid gland. It is important for clinicians to be aware that, on rare occasions, facial nerve dysfunction may result from benign parotid disease.
Cefepime versus Ceftazidime as Empiric Therapy for Fever in Neutropenic Patients with Cancer
Authors: Chandrasekar Pranatharthi H , Arnow Paul M
Published: June 2003

OBJECTIVE:

To compare the efficacies of cefepime and ceftazidime as empiric therapy during the management of fever in cancer patients with chemotherapy-induced neutropenia.

METHODS:

A prospective, double-blind, randomized study of cefepime 2 g every eight hours and ceftazidime 2 g every eight hours was performed in 276 adult neutropenic (absolute neutrophil count <500/mm3) cancer patients with fever.

RESULTS:

Median duration of neutropenia was five days. Sixty-one percent (n = 188) of the patients were evaluable. Treatment was successful in 57% (58/101) of cefepime-treated patients and 60% (52/87) of ceftazidime-treated patients (95% CI −18 to 12; p = 0.77). Bacteremic clearance occurred in 71% (12/17) of cefepime-treated patients and 40% (6/15) of ceftazidime-treated patients (p = 0.3). Both drugs were well tolerated.

CONCLUSIONS:

Cefepime appears to be as effective as ceftazidime in the initial treatment of febrile episodes in adult cancer patients with chemotherapy-associated neutropenia of modest duration.
Evaluation of Outcomes in Converting from Intravenous Ondansetron to Oral Granisetron: An Observational Study
Authors: McCune Jeannine S , Oertel Maryann D , Pfeifer Dennis , Houston Shelly A , Bingham Andrea , Sawyer William T , Lindley Celeste M
Published: June 2003

OBJECTIVE:

To describe a systematic evaluation of the outcomes associated with revising institutional guidelines for the prevention of acute chemotherapy-induced nausea and vomiting (CINV) to promote cost-effective use of the serotonin (5-HT3) antagonists.

METHODS:

The 5-HT3 antagonist of choice in the antiemetic guidelines was revised from intravenous ondansetron to oral granisetron in August 1995. Patient assessments were conducted immediately prior to (Period 1) and after (Period 2) guideline revision using validated questionnaires. The effectiveness of the two 5-HT3 antagonists were compared and reported to the prescribing oncologists. Outcomes were assessed one year after guideline revision (Period 3) using identical methods.

RESULTS:

No difference was found in the rate of total control (no emesis, no nausea) between patients receiving oral granisetron (60%) and intravenous ondansetron (56%) (p = 0.408, Period 1 vs. 2). Nausea severity, the number of emesis episodes, and use of rescue antiemetics were also equivalent. Prescriber compliance with using the 5-HT3 antagonist of choice and dose increased from 48% to 61% following adoption of oral granisetron. By Period 3, compliance increased to 78%, and satisfactory control of acute CINV was again documented. The costs for prevention of acute CINV decreased from $107 in Period 1 (intravenous ondansetron only) to $65 in Period 3 (oral granisetron).

CONCLUSIONS:

Outcomes associated with use of oral granisetron and intravenous ondansetron were equivalent in this patient population. Guideline revision and outcome documentation by the oncology pharmacists resulted in increased compliance with institution guidelines and a 40% cost savings.
Hypothyroidism and Depression: A Therapeutic Challenge
Authors: Rack Sarah Kotchen , Makela Eugene H
Published: June 2003

OBJECTIVE:

To describe a patient with longstanding depression and hypothyroidism who had marked mood improvement only after triiodothyronine (T3) was added to her thyroxine (T4) replacement therapy. CASE SUMMARY: A 50-year-old white woman had a long history of depression and documented hypothyroidism since 1991. Despite treatment with T4 with dosages up to 0.3 mg/d, she continued to be depressed, have symptoms of hypothyroidism, and have a persistently elevated thyroid-stimulating hormone concentration. Addition of a low dose of T3 to her regimen resulted in significant mood improvement. DISCUSSION: The relationship between hypothyroidism and depression is well known. It is possible that this patient's long history of depression may have been a consequence of inadequately treated hypothyroidism, due either to poor patient compliance or resistance to T4. Nevertheless, her depression responded to addition of a low dose of T3 to her regimen. This case emphasizes the importance of screening depressed patients for hypothyroidism. Her clinical course also suggests that depression related to hypothyroidism may be more responsive to a regimen that includes T3 rather than to replacement with T4 alone. This is consistent with the observation that T3 is superior to T4 as adjuvant therapy in the treatment of unipolar depression.

CONCLUSIONS:

Depressed patients should be screened for hypothyroidism. In hypothyroid patients, depression may be more responsive to a replacement regimen that includes T3 rather than T4 alone. Therefore, inclusion of T3 in the treatment regimen may be warranted after adequate trial with T4 alone.
Treatment of Affective Disorder and Obesity with Topiramate
Authors: Teter Christian J , Early John J , Gibbs Carol M
Published: June 2003

OBJECTIVE:

To report a case of weight loss and mood stabilization in a patient being treated with the antiepileptic drug topiramate.

CASE SUMMARY:

A 37-year-old obese white woman with affective instability and obesity was being treated with adjunctive topiramate therapy. The patient lost 10 kg over 10 weeks of treatment with topiramate and improved clinically, as evidenced by a reduction in the number of × that she had to be admitted to a management unit for constant observation, and a decrease in the number of × that mechanical restraints or medication interventions were required for aggressive outbursts. Furthermore, the patient successfully completed two home visits while receiving topiramate therapy and was out of the hospital on her third home visit at the time of this writing.

DISCUSSION:

This case further strengthens previous reports that topiramate may be useful in treating affective disorders as well as inducing weight loss in a patient population in which weight gain is common. The patient discussed in this case report had no acute illnesses or changes in health status, no changes in diet, and no changes in her medications that could have accounted for the sudden weight loss. In addition, the patient's behavior did not improve until topiramate was added as adjunctive therapy of valproic acid, citalopram, and chlorpromazine during an adequate trial period.

CONCLUSIONS:

Controlled studies need to be performed to evaluate the use of topiramate in the psychiatric population and, in particular, the benefits of topiramate therapy in psychiatric patients with an additional diagnosis of obesity.
Toxic Metronidazole-Induced MRI Changes
Authors: Horlen Cheryl K , Seifert Charles F , Malouf Cathy S
Published: June 2003

OBJECTIVE:

To report a case of changes documented by magnetic resonance imaging (MRI) of the head probably due to accumulation of metronidazole in a patient with liver dysfunction.

CASE SUMMARY:

A 34-year-old Hispanic man with cirrhosis and hepatitis C being treated with metronidazole for Bacteroides fragilis meningitis and bacteremia developed ataxia, disorientation, and peripheral neuropathy. An MRI at the time meningitis was diagnosed was negative. After the patient received >60 g of metronidazole, an MRI revealed increased signal intensity below, behind, and lateral to the fourth ventricle. Concomitant metronidazole serum concentration was toxic at 35.1 μg/mL.

DISCUSSION:

This is the second reported case of metronidazole-induced MRI changes. Metronidazole is known to accumulate in patients with liver dysfunction and can cause peripheral neuropathy and central nervous system (CNS) dysfunction; these effects may take up to two years to completely resolve.

CONCLUSIONS:

Metronidazole dosages should be reduced in patients with liver dysfunction to prevent the accumulation of metronidazole, which can lead to CNS dysfunction and peripheral neuropathy.
Interactions of Warfarin with Garlic, Ginger, Ginkgo, or Ginseng: Nature of the Evidence
Authors: Vaes Leon PJ , Chyka Peter A
Published: June 2003

OBJECTIVE:

To review and characterize the evidence describing potential interactions between warfarin and garlic, ginger, ginkgo, or ginseng.

DATA SOURCES:

Searches of MEDLINE (1966–1999), other bibliographic databases, several abstracting services, and tertiary references were conducted.

STUDY SELECTION AND DATA EXTRACTION:

Articles were examined by each author, and additional citations were obtained from the references of these articles. Preference was given to English-language articles of human studies.

DATA SYNTHESIS:

Evidence is lacking for an interaction of warfarin with garlic or ginger. One case report associates ginseng use with decreased warfarin-maintained anticoagulation effect. Another case report links concomitant use of ginkgo and warfarin with the development of intracerebral hemorrhage. Hemorrhage and bleeding tendencies were noted in four cases with ginkgo use and in three cases with garlic; in none of these cases were patients receiving warfarin.

CONCLUSIONS:

The true risks of these interactions and effects are difficult to characterize due to the limited number and nature of existing reports.
Practice Guidelines for Lipid-Based Amphotericin B in Stem Cell Transplant Recipients
Authors: Quilitz Rod E , Arnold Alana D , Briones Gabriel R , Dix Suzanne P , Ippoliti Cindy , Kennedy LeAnne D , Lucich Jeanne L , Mehta Jayesh , Peters Byron G , Tice David S
Published: June 2003

OBJECTIVE:

To provide clinicians who practice in the stem cell transplantation (SCT) setting with practical guidelines for the use of lipid-based amphotericin B (AmB) formulations in SCT patients who have documented or probable invasive fungal infections, are experiencing neutropenic fever, or require secondary prophylaxis for fungal infections.

DATA SOURCES:

Recommendations are based on the results of a two-day consensus meeting that convened clinicians versed in the management of infectious complications in patients undergoing SCT. This meeting, which was held October 21–23, 1998, in Orlando, Florida, was sponsored by an educational grant from The Liposome Company. In addition, primary articles were identified by MEDLINE search (1980–December 1999) and through secondary sources.

STUDY SELECTION AND DATA EXTRACTION:

All of the articles identified from the data sources were evaluated, and all information deemed relevant was included in this review.

DATA SYNTHESIS:

Immunocompromised patients, particularly patients undergoing high-dose chemotherapy with SCT, experience a high degree of morbidity and mortality from invasive fungal infections. Historically, treatment for such infections with conventional AmB had been limited primarily by its associated nephrotoxicity. Lipid-based formulations of AmB have helped to advance the management of invasive fungal infections in the SCT population by offering a treatment alternative that allows for administration of adequate amounts of active drug to produce clinical and mycologic responses, compared with conventional AmB, in a delivery system that is less nephrotoxic. Unfortunately, these agents are relatively expensive. Therefore, patients who are candidates for lipid-based products must be selected carefully.

CONCLUSIONS:

Practical guidelines are provided for the use of lipid-based AmB formulations in SCT patients who have documented or probable invasive fungal infections, are experiencing neutropenic fever, or require secondary prophylaxis for fungal infections.