bluuebunny/crossref_metadata_2025 huggingface dataset:
Algorithms for Interactive Editing of Level Set Models
Authors: Museth Ken , Breen David E. , Whitaker Ross T. , Mauch Sean , Johnson David
Published: December 2005

Level set models combine a low‐level volumetric representation, the mathematics of deformable implicit surfaces and powerful, robust numerical techniques to produce a novel approach to shape design. While these models offer many benefits, their large‐scale representation and numerical requirements create significant challenges when developing an interactive system. This paper describes the collection of techniques and algorithms (some new, some pre‐existing) needed to overcome these challenges and to create an interactive editing system for this new type of geometric model. We summarize the algorithms for producing level set input models and, more importantly, for localizing/minimizing computation during the editing process. These algorithms include distance calculations, scan conversion, closest point determination, fast marching methods, bounding box creation, fast and incremental mesh extraction, numerical integration and narrow band techniques. Together these algorithms provide the capabilities required for interactive editing of level set models.
A Family of Inexpensive Sampling Schemes
Authors: Hasselgren Jon , Akenine‐Möller Tomas , Laine Samuli
Published: December 2005

To improve image quality in computer graphics, antialiazing techniques such as supersampling and multisampling are used. We explore a family of inexpensive sampling schemes that cost as little as 1.25 samples per pixel and up to 2.0 samples per pixel. By placing sample points in the corners or on the edges of the pixels, sharing can occur between pixels, and this makes it possible to create inexpensive sampling schemes. Using an evaluation and optimization framework, we present optimized sampling patterns costing 1.25, 1.5, 1.75 and 2.0 samples per pixel.
Programmable Multiple Pacing Configurations Help to Overcome High Left Ventricular Pacing Thresholds and Avoid Phrenic Nerve Stimulation
Authors: GUREVITZ OSNAT , NOF EYAL , CARASSO SHEMY , LURIA DAVID , BAR‐LEV DAVID , TANAMI NECHEMYA , ELDAR MICHAEL , GLIKSON MICHAEL
Published: December 2005

Background: High left ventricular pacing (LVP) thresholds and phrenic nerve stimulation (PNS) are common problems with cardiac resynchronization (CRT). Newer systems capable of multiple LVP configurations may help overcome these problems without the need for reoperation.

Methods: CRT systems capable of multiple LVP configurations (Guidant models H155 and H145) were implanted in 43 patients (study group). An additional 49 patients (control group) received CRT systems (Guidant, Medtronic, Biotronik, St. Jude Medical, various models) lacking this feature.

Results: Overall, acute high (≥2.5 V/0.5 ms) LVP thresholds were encountered in 13 (30%) of the study group, and 25 (50%) of control group patients (P = 0.03). PNS was encountered in 5 (12%) of the study group and 12 (24%) of control group patients (P = 0.13). All cases of high LVP thresholds and PNS in the study group were managed by switching to a different LVP configuration, while high thresholds remained in control group patients, and PNS was managed by replacing the lead. The CS lead was successfully placed in a lateral branch in 95% of study group, compared to only 77% of control group patients (P = 0.004).

Conclusions: Multiple LVP configurations were clinically useful in a significant number of patients undergoing CRT system implantation by helping to overcome high LVP thresholds and PNS, and by providing more flexibility in placing the LV lead.
Does a Gender Difference in Response to Cardiac Resynchronization Therapy Exist?
Authors: BLEEKER GABE B. , SCHALIJ MARTIN J. , BOERSMA ERIC , STEENDIJK PAUL , VAN DER WALL ERNST E. , BAX JEROEN J.
Published: December 2005

Background: Cardiac resynchronization therapy (CRT) has a beneficial effect on clinical symptoms, exercise capacity, and systolic left ventricular (LV) performance in patients with heart failure. The aim of the current study was to evaluate whether a gender difference exists in response to CRT.

Methods: Consecutive patients with end‐stage heart failure (New York Heart Association, NYHA, class III–IV), LV ejection fraction (LVEF) ≤35%, QRS duration >120 ms, and left bundle branch block configuration underwent CRT. At baseline and 6 months post‐CRT, clinical and echocardiographic parameters were evaluated; follow‐up was obtained up to 5 years. The effects of CRT were compared between women and men.

Results: The study population comprised 137 men and 36 women (mean age 66 ± 11 years). No differences in baseline characteristics were observed except that nonischemic cardiomyopathy was more frequent in women than men (67% vs 38%, P < 0.05). In all patients, clinical and echocardiographic parameters improved significantly at 6‐month follow‐up. The magnitude of improvement in different parameters was similar between women and men, e.g., the improvement in NYHA Class was 0.9 ± 0.6 in women and 1.0 ± 0.7 in men (NS) and the increase in LVEF was 8 ± 8% in women as compared to 7 ± 9% in men (NS). The percentage of individual responders was not different between women and men (76% vs 80%, NS) and 2‐year survival was comparable for women and men (84% vs 80%, NS).

Conclusion: No gender differences were observed in response to CRT and long‐term survival after CRT.
The Role of Swab and Tissue Culture in the Diagnosis of Implantable Cardiac Device Infection
Authors: DY CHUA JIMMY , ABDUL‐KARIM AHMAD , MAWHORTER STEVEN , PROCOP GARY W. , TCHOU PATRICK , NIEBAUER MARK , SALIBA WALID , SCHWEIKERT ROBERT , WILKOFF BRUCE L.
Published: December 2005

Background: The isolation of a pathogen is vital in the diagnosis and treatment of a device infection. A swab culture, despite poor sensitivity, is the most common method used in specimen collection.

Objective: To determine the relative value of swab and tissue specimen cultures in patients with implantable cardiac pacemakers and defibrillators.

Design: Prospective patient cohort study.

Setting: A 1,000‐bed tertiary referral center in Cleveland, Ohio.

Patients: Consecutive patients with implantable cardiac pacemaker or defibrillator presenting for lead extraction from October 1, 2000 to March 31, 2001.

Methods: Tissue and swab cultures were prospectively collected during pacemaker and implantable defibrillator surgeries that required lead extraction. Clinical manifestations, microbiology, and echocardiographic data were recorded in patients with and without a clinical diagnosis of device system infection.

Results: Seventy‐one patients with implantable pacemaker (n = 49, 69%), implantable defibrillator (n = 18, 25%), or both devices (n = 4, 6%) requiring lead extraction had pocket swab and tissue cultures for analysis. Infection was evident clinically in 35 (49%) of the patients and absent in the remainder. The most common bacteria isolated were coagulase‐negative Staphylococcus (37%) and Staphylococcus aureus (10%). Patients with clinical infection had positive cultures more frequently (P = 0.002) by pocket tissue culture (n = 24, 69%) than by swab culture (n = 11, 31%). However, patients without clinical infections had positive cultures at similar rates by pocket tissue culture (n = 10, 28%) and by swab culture (n = 8, 22%; P = 0.48). Patients without clinical infection were not treated with other than perioperative antibiotics, and did not develop clinical infections.

Conclusion: Pocket tissue cultures are more effective than pocket swab cultures for the isolation and identification of the infectious pathogens in cardiac device infections. Positive cultures by pocket swab or tissue cultures in the absence of clinical signs and symptoms of infection does not imply infection or the need for specific therapy.
Usefulness of Atrial Fibrillation Burden as a Predictor for Success of Pulmonary Vein Isolation
Authors: BERKOWITSCH ALEXANDER , GREISS HARALD , VUKAJLOVIC DEJAN , KUNISS MALTE , NEUMANN THOMAS , ZALTSBERG SERGEJ , KURZIDIM KLAUS , HAMM CHRISTIAN , PITSCHNER HEINZ F.
Published: December 2005

Background: The definition of symptomatic improvement after pulmonary vein isolation (PVI) is controversial. We assessed primarily the usefulness and predictive accuracy (PA) of AF (atrial fibrillation) burden (AFB) within the first 3 months after the procedure as an early predictor for curative success as well as reduction of symptoms.

Methods: We studied 100 pts (62 men, mean age: 54 ± 9 years, LVEF: 57 ± 9%, paroxysmal AF, 85, persistent AF, 15) who underwent PVI. RF ablation was used in 63 patients. The combination of cryoablation and RF (Hybrid therapy) was used in the remaining 37 patients, in 19 patients of whom additionally linear lesions were performed. All patients were followed up 3 months after PVI (the blanking period) and every 3 months thereafter. The significance of early recurrence of AF (ERAF) was separately analyzed for RF and for hybrid therapy arm. Quality of life (QoL) was assessed using the physical composite summary score (PCS) and mental composite summary score (MCS). AFB was dichotomized at: 0, 0.5, 1, 6, 12, and 24 hours.

Results: ANOVA revealed significant differences between PCS at baseline and after PVI in patients without recurrence and with those with postablation AFB <12 hours. There was no difference between PCS in patients with AFB ≥12 hours within a 3 months interval and PCS at baseline. ERAF occurred in 35% of patients (16 patients, AFB ≥12 hours). Symptomatic ERAF occurred in 29 patients (17 patients AFB ≥12 hours). After the blanking period, documented AF recurrence was found in 50 patients (17 patients, AFB ≥12 hour). Symptomatic late recurrence was found in 47 patients (31 patients with AFB ≥12 hours). Absence of ERAF was revealed to be predictive for long‐term success and symptomatic ERAF was found to be predictive for symptomatic AF recurrence (P <0.0001).

Conclusion: AF recurrence with AFB ≥12 hours within 3 months is associated with a missed improvement of QoL. Symptomatic ERAF predicts recurrence independently of therapy.
Ten Year Follow‐Up After Radiofrequency Catheter Ablation for Atrioventricular Nodal Reentrant Tachycardia in the Early Days Forever Cured, or a Source for New Arrhythmias?
Authors: KIMMAN G.P. , BOGAARD M.D. , VAN HEMEL N.M. , VAN DESSEL P.F.H.M. , JESSURUN E.R. , BOERSMA L.V.A. , WEVER E.F.D. , THEUNS D.A.M.J. , JORDAENS L.J.
Published: December 2005

Background: Radiofrequency (RF) catheter ablation is highly effective with a low complication rate. However, lesions created by RF energy are irreversible, inhomogeneous, and therefore potentially proarrhythmic.

Objectives: The aim of this study was to examine the magnitude and importance of long‐term proarrhythmic effects of RF energy.

Methods and Results: Between 1991 and 1995, 120 patients underwent RF ablation for atrioventricular nodal reentrant tachycardia (AVNRT). Patient data were collected by contacting patients and/or filling out a questionnaire, and medical files were screened for recurrent, documented arrhythmias, pharmacological treatment, and repeated EP study. Referring cardiologists were asked about recurrences of tachyarrhythmias. Fourteen patients (11%) were lost to follow‐up. During a mean follow‐up of 10 years, six patients died. Recurrences of AVNRT were not any more observed after 3 years after ablation. A total of 29 patients (24%) suffered from new arrhythmias, 6 from type 1 atrial flutter, 6 from atrial tachycardia, 9 from atrial fibrillation, and finally 16 from symptomatic premature atrial contractions (PACs), needing medical treatment or a combination of these arrhythmias. Nine patients underwent pacemaker implantation, 4 after developing procedural atrioventricular (AV) conduction disturbances, 2 after His ablation for permanent atrial fibrillation, 1 patient for sick sinus syndrome, and another 2 patients after developing late AV block, respectively, 7 and 9 years after ablation.

Conclusion: During long‐term follow‐up after RF ablation for AVNRT, no AVNRT recurrences were observed, but 29 patients (24%) suffered from new arrhythmias or late AV block. This potential proarrhythmic effect of RF energy promotes the application of alternative energy sources for ablative therapies for cardiac arrhythmias.
Pacemaker Auto‐Interference by Thoracic Impedance Measurement for the Rate Response Function
Authors: KOLB CHRISTOF , MARKWARDT CHRISTINA , ZRENNER BERNHARD , SCHMITT CLAUS
Published: December 2005

This report describes two cases of pacemaker auto‐interference caused by thoracic impedance measurements for the rate response function of a dual chamber pacemaker. Mechnisms of this phenomenon and reprogramming strategies are discussed.
Clinical, biochemical, and electrocardiographic aspects of Trypanosoma cruzi infection in free‐ranging golden lion tamarins (Leontopithecus rosalia)
Authors: Monteiro Rafael Veríssimo , Baldez Jennifer , Dietz James , Baker Andrew , Lisboa Cristiane Varella , Jansen Ana Maria
Published: December 2005

Background  Wild golden lion tamarins from the Biological Reserve of Poço das Antas, Rio de Janeiro, Brazil, have high prevalence of Trypanosoma cruzi infection leading us to clinically assess the disease in this endangered species.

Methods  34 tamarins were sampled for the presence of T. cruzi infection (through serology) and clinical evaluation (electrocardiography, blood counts and biochemical analysis).

Results  32% of the sampled tamarins were T. cruzi positive, 45% of these displayed cardiac abnormalities. Main cardiac abnormality in infected tamarins was T wave low voltage; R wave low voltage and V3S wave high voltage were also found. The tamarins displaying T wave low voltage had high proportion of seric cardiac creatine kinase. Seric mean total protein was significantly higher in infected tamarins.

Conclusions  Sampled tamarins displayed typical signs of T. cruzi infection, similar to experimentally infected primates and human natural infection. Potential risk of T. cruzi infection to this endangered species is discussed.
The Inner Tegument Promotes Herpes Simplex Virus Capsid Motility Along Microtubules in vitro
Authors: Wolfstein André , Nagel Claus‐Henning , Radtke Kerstin , Döhner Katinka , Allan Victoria J. , Sodeik Beate
Published: December 2005

After viral fusion, capsids of the neurotropic herpes simplex virus are transported along microtubules (MT) to the nuclear pores for viral genome uncoating, nuclear transcription and replication. After assembly and egress from the nucleus, cytosolic capsids are transported to host membranes for secondary envelopment or to the axon terminal for further viral spread. Using GFP‐tagged capsids, Cy3‐labelled MT and cytosol, we have reconstituted viral capsid transport in vitro. In the presence of ATP, capsids moved along MT up to 30 µm. Blocking the function of dynactin, a cofactor of dynein and kinesin‐2, inhibited the transport. Removing outer tegument proteins from the capsids increased in vitro motility. In contrast, capsids isolated from infected nuclei that were devoid of inner as well as outer tegument proteins showed little interaction with dynein and its cofactor dynactin. Our data suggest that the inner tegument of alphaherpesviruses contains viral receptors for MT motors.
Abundance and Leaf Damage Caused by Gall‐Inducing Insects in a Mexican Tropical Dry Forest1
Authors: Cuevas‐Reyes Pablo , Quesada Mauricio , Oyama Ken
Published: December 2005

We evaluated the temporal and spatial patterns of abundance and the amount of damage caused by gall‐inducing insects (GII) in deciduous and riparian habitats in a seasonal tropical dry forest in Mexico. Plants occurring in these habitats differ in their phenology and moisture availability. Deciduous habitats are seasonal and xeric, while riparian habitats are aseasonal and mesic. We found 37 GII species and each one was associated with a specific plant species. In total, 19 species (51.3%) were present in deciduous habitats, 13 species (35.2%) in riparian habitats, and only 5 species (13.5%) occurred in both. Abundance and leaf damage by GII were greater in deciduous than in riparian habitats during the wet season. For each GII species that occurred in both habitats, host plant species supported greater abundance and leaf damage by GII in deciduous habitats during the wet season. These results indicate a greater association of GII species with host plants in deciduous than in riparian habitats during the wet season. In riparian habitats, 11 plant species (61.1%) had greater density of GII in the dry than in the wet season. Similarly, leaf damage by GII was significantly greater in the dry than in the wet season in riparian habitats for 12 plant species (66.7%). Dry forest plants of riparian habitats presented two peaks of leaf‐flushing: GII colonized leaves produced in the first peak at the beginning of the wet season, and accumulated or recolonized leaves in the second peak at the beginning of the dry season. The levels of leaf damage by GII detected in this study in the rainy season were considerably higher than those obtained for folivorous insects in other neotropical forests, suggesting that this GII guild might have an important impact on their host plant species in this tropical community.
Myocardial infarction in young adults
Authors: Egred M , Viswanathan G , Davis G K
Published: December 2005

Although myocardial infarction (MI) mainly occurs in patients older than 45, young men or women can suffer MI. Fortunately, its incidence is not common in patients younger than 45 years. However, the disease carries a significant morbidity, psychological effects, and financial constraints for the person and the family when it occurs at a young age. The causes of MI among patients aged less than 45 can be divided into four groups: (1) atheromatous coronary artery disease; (2) non-atheromatous coronary artery disease; (2) hyper-coagulable states; (4) MI related to substance misuse. There is a considerable overlap between all the groups. This article reviews the literature and highlights the practical issues involved in the management of young adults with MI.
Dynamic confidence during simulated clinical tasks
Authors: Byrne A J , Blagrove M T , McDougall S J P
Published: December 2005

Objective

Doctors’ confidence in their actions is important for clinical performance. While static confidence has been widely studied, no study has examined how confidence changes dynamically during clinical tasks.

Method

The confidence of novice (n = 10) and experienced (n = 10) trainee anaesthetists was measured during two simulated anaesthetic crises, bradycardia (easy task) and failure to ventilate (difficult task).

Results

As expected, confidence was high in the novice and experienced groups in the easy task. What was surprising, however, was that confidence during the difficult task decreased for both groups, despite appropriate performance.

Conclusions

Given that confidence affects performance, it is alarming that doctors who may be acting unsupervised should lose dynamic confidence so quickly. Training is needed to ensure that confidence does not decrease inappropriately during a correctly performed procedure. Whether time on task interacts with incorrect performance to produce further deficits in confidence should now be investigated.
Predictors of mortality in mechanically ventilated patients
Authors: Sudarsanam T D , Jeyaseelan L , Thomas K , John G
Published: December 2005

Objectives

There are scarce data from India validating scoring systems used to predict outcome in patients requiring mechanical ventilation. This study prospectively compared the organ system failure (OSF), the acute physiology and chronic health evaluation (APACHE) II, and the APACHE III, scores on patients requiring mechanical ventilation in the medical intensive care unit, to predict outcome.

Methods

200 consecutive patients requiring mechanical ventilation in a medical intensive care unit were recruited. OSF, APACHE II, and APCHE III scores were calculated at admission and daily for one week or until discharge in all patients. Other variables recorded include age, sex, diagnosis, oxygen therapy before ventilation, complications on ventilation, duration in hospital before ventilation, duration of ventilation, type of respiratory failure, alveolar arterial oxygen gradient, P/F ratio, use of tracheostomy, time on ventilator before tracheostomy, muscle relaxant used, fluid balance, inotrope support. Logistic regression analysis and area under the curve were computed to determine which variables independently predict outcome.

Results

Of the 200 patients, at discharge 143 patients (71.5%) had died. The factors that independently predicted outcome among these patients on mechanical ventilation were the type of respiratory failure (type I) OR = 2.7 (p = 0.02), the use of inotropes OR 2.4 (p = 0.04), and the APACHE II score OR = 1.8 (p = 0.008) for every five point increase in APACHE II score.

Conclusions

Type 1 respiratory failure, the use of inotropes, and the APACHE II score measured at admission are significant independent predictors of mortality in the patients on mechanical ventilation.
Diagnosis and treatment of caecal volvulus
Authors: Consorti E T , Liu T H
Published: December 2005

Caecal volvulus is an infrequently encountered clinical condition and an uncommon cause of intestinal obstruction. Patients with this condition may present with highly variable clinical presentations ranging from intermittent, self limiting abdominal pain to acute abdominal pain associated with intestinal strangulation and sepsis. Lack of familiarity with this condition is a factor contributing to diagnostic and treatment delays. The objective of this review is to promote clinicians’ awareness of this disease through patient case illustration, discussion of disease pathogenesis, clinical features, and management strategies.
CONVERGENCE PROPERTY AND MODIFICATIONS OF A MEMORY GRADIENT METHOD
Authors: SHI ZHEN-JUN , SHEN JIE
Published: December 2005

We study properties of a modified memory gradient method, including the global convergence and rate of convergence. Numerical results show that modified memory gradient methods are effective in solving large-scale minimization problems.
GLOBAL CONVERGENCE OF SHORTEST-RESIDUAL FAMILY OF CONJUGATE GRADIENT METHODS WITHOUT LINE SEARCH
Authors: LI XIA , CHEN XIONGDA
Published: December 2005

The shortest-residual family of conjugate gradient methods was first proposed by Hestenes and was studied by Pytlak, and Dai and Yuan. Recently, a no-line-search scheme in conjugate gradient methods was given by Sun and Zhang, and Chen and Sun. In this paper, we show the global convergence of two shortest-residual conjugate gradient methods (FRSR and PRPSR) without line search. In addition, computational results are presented to show that the methods with line search have similar numerical behavior to the methods without line search.
A MARKOV REPAIRABLE SYSTEM INVOLVING AN IMPERFECT SERVICE STATION WITH MULTIPLE VACATIONS
Authors: KE JAU-CHUAN , LIN CHUEN-HORNG
Published: December 2005

The main purpose of this paper is to study the reliability and availability of a system with M operating devices, m spares, and an imperfect service station that takes vacations. Specifically, once there are no failed devices in the system, the service station takes consecutive vacations until there is at least one failed device upon its return from vacation. The service station may break down and require repair at a repair facility. This paper derives the reliability, the mean time to system failure, the availability, and failure frequency of the K-out-of-M + m system. Numerical simulation of the impacts of system parameters as well as sensitivity analysis for the reliability, the mean time to system failure, the availability and failure frequency is performed.
QUANTUM VERSION OF THE SZILARD ONE-ATOM ENGINE AND THE COST OF RAISING ENERGY BARRIERS
Authors: GEA-BANACLOCHE JULIO , LEFF HARVEY S.
Published: December 2005

We present a variation on the Szilard one-atom engine "paradox," in which an adiabatic (in the quantum-mechanical sense) splitting of the container removes the need for a demon or measurement. We show that the solution depends on an interesting difference between the energetic cost of raising partitions in quantum and classical containers.
ROBUST GPS SATELLITE SIGNAL ACQUISITION USING WAVELET
Authors: DJEBBOURI MOHAMED , DJEBOURI DJAMEL
Published: December 2005

In Global Positioning System (GPS), receivers use FFT-based convolvers to acquire the signals. This paper shows a robust substitute algorithm for calculating the convolution that is less sensitive to additive noise.
STABILITY OF FRAMES GENERATED BY NONLINEAR FOURIER ATOMS
Authors: CHEN QIUHUI , LI LUOQING , QIAN TAO
Published: December 2005

In this paper, we study the stability of two kinds of frames generated by nonlinear Fourier atoms. The first result is the Kadec type ¼-theorem. The second states that the nonlinear windowed Fourier atoms form a frame of L2(ℝ).
SOFT-THRESHOLDING FOR DENOISING OF MEDICAL IMAGES — A MULTIRESOLUTION APPROACH
Authors: KHARE ASHISH , TIWARY UMA SHANKER
Published: December 2005

Medical images generally have low contrast and they get complex type of noise due to the use of various devices and applications of various algorithms. However, most of the denoising methods consider only additive noise or some special noise model dependent on their systems and conditions only. Such methods when applied to real medical images yield poor results.

The present work proposes a method for denoising of medical images using soft-thresholding in wavelet domain on multiple levels. We have developed a method to compute the threshold values for denoising of medical images, which depend on the median as well as the contrast ratio of the wavelet coefficients and also on the level number. We have performed experiments by adding various proportions of Gaussian, Salt-and-Pepper and Speckle noise, and found that the proposed method performs better for these cases. The method is efficient because the threshold values can be calculated directly and it is adaptive as these values depend on mean, median and standard deviation of wavelet coefficients of the particular image. The proposed method also gives a criterion for level-dependent thresholding. Application of the proposed method to Ultrasound, X-ray and MRI images is demonstrated in experiments. In the present work, we have also done studies on how to select the mother wavelet for a particular problem.
GENERAL FRAMEWORK FOR CONSISTENT SAMPLING IN HILBERT SPACES
Authors: ELDAR YONINA C. , WERTHER TOBIAS
Published: December 2005

We introduce a general framework for consistent linear reconstruction in infinite-dimensional Hilbert spaces. We study stable reconstructions in terms of Riesz bases and frames, and generalize the notion of oblique dual frames to infinite-dimensional frames. As we show, the linear reconstruction scheme coincides with the so-called oblique projection, which turns into an ordinary orthogonal projection when adapting the inner product. The inner product of interest is, in general, not unique. We characterize the inner products and corresponding positive operators for which the new geometrical interpretation applies.
A NOVEL APPROACH COMBINING GABOR WAVELET AND MOMENTS FOR TEXTURE SEGMENTATION
Authors: MUNEESWARAN K. , GANESAN L. , ARUMUGAM S. , HARINARAYAN P.
Published: December 2005

In this work, an effective method has been proposed for texture segmentation, which incorporates the best features of filter bank and statistical approaches. This technique combines the features of Gabor wavelets (filter based) and General Moments (statistical) approaches. The method has been successfully tested for various textures from Brodatz texture collection. The relative performance of this method against the conventional approaches has been analyzed using Fisher Criterion.
AN OPERATOR SPLITTING PRECONDITIONER FOR MATRICES ARISING FROM A WAVELET BOUNDARY ELEMENT METHOD FOR THE HELMHOLTZ EQUATION
Authors: HAWKINS STUART C. , CHEN KE , HARRIS PAUL J.
Published: December 2005

An operator splitting type preconditioner is presented for fast solution of linear systems obtained by Galerkin discretization of the Burton and Miller formulation for the Helmholtz equation. Our approach differs from usual boundary element treatments of the three-dimensional scattering problem because we use a basis of biorthogonal wavelets. Such wavelets result in a sparse linear system and that facilitates preconditioning and makes matrix vector products cheap to form. In this Part I of our work, we implement a biorthogonal wavelet transform on a closed surface in three dimensions. Numerical results demonstrate the gains in efficiency that are already achievable with this convenient but non-optimal implementation.
Corticosteroids prevent myofibroblast accumulation and airway remodeling in mice
Authors: Miller Marina , Cho Jae Youn , McElwain Kirsti , McElwain Shauna , Shim Jung Yeon , Manni Michael , Baek Ji Sun , Broide David H.
Published: December 2005

At present there are conflicting results from studies investigating the role of corticosteroids in inhibiting airway remodeling in asthma. We have used a mouse model to determine whether administration of corticosteroids prevents the development of allergen-induced structural features of airway remodeling. Mice treated with corticosteroids were subjected to repetitive ovalbumin (OVA) challenge for 3 mo, at which time levels of peribronchial fibrosis and the thickness of the peribronchial smooth muscle layer were assessed by immunohistology, levels of transforming growth factor (TGF)-β1 by ELISA, and the number of α-smooth muscle actin+/Col-1+ peribronchial myofibroblasts by immunohistochemistry. Corticosteroids significantly reduced allergen-induced increases in peribronchial collagen deposition and levels of total lung collagen but did not reduce allergen-induced increases in the thickness of the peribronchial smooth muscle layer. Levels of lung TGF-β1 were significantly reduced in mice treated with systemic corticosteroids, and this was associated with a significant decrease in the number of peribronchial inflammatory cells that expressed TGF-β1, including eosinophils and mononuclear cells. Corticosteroids also significantly reduced the number of peribronchial myofibroblasts. Overall, these studies demonstrate that administration of corticosteroids significantly reduces levels of allergen-induced peribronchial fibrosis. The reduction in peribronchial fibrosis mediated by corticosteroids is likely to be due to several mechanisms including inhibition of expression of TGF-β1, a reduction in the number of peribronchial inflammatory cells expressing TGF-β1 (eosinophils, macrophages), as well as by corticosteroids reducing the accumulation of peribronchial myofibroblasts that contribute to collagen expression.
Twistor fibrations giving primitive harmonic maps of finite type
Authors: Pacheco Rui
Published: December 2005

Primitive harmonic maps of finite type from a Riemann surface M into a k‐symmetric space G/H are obtained by integrating a pair of commuting Hamiltonian vector fields on certain finite‐dimensional subspaces of loop algebras. We will clarify and generalize Ohnita and Udagawa′s results concerning homogeneous projections p : G/H → G/K, with H ⊂ K, preserving finite‐type property for primitive harmonic maps.
Existence of solution for a singular elliptic equation with critical Sobolev‐Hardy exponents
Authors: Li Juan
Published: December 2005

Via the variational methods, we prove the existence of a nontrivial solution to a singular semilinear elliptic equation with critical Sobolev‐Hardy exponent under certain conditions.
On a certain lubrication slip model
Authors: Hadi Khalid Ait , El Bansami My Hafid
Published: December 2005

We consider a stationary equation modeling the slip flow in a hard disk drive. A result of existence is proven under different hypotheses than in the literature. The uniqueness of solution followed from monotonicity techniques for nonlinear PDEs.
Wavelet‐type frames and wavelet‐type bases
Authors: Shamooshaky M. M.
Published: December 2005

The concepts of basis and frame are studied in the classical literature of functional analysis, Fourier analysis, and wavelet theory in a wide range. In this paper, we consider an operator‐theoretic approach to discrete frame theory on a separable Hilbert space. For this purpose, we define a special type of frames and bases, called wavelet‐type frames and wavelet‐type bases, obtained by acting with a family of bounded linear operators on some vectors, and then investigate the elementary properties of these concepts.
On pairs of subrings with a common set of proper ideals
Authors: Hirano Yasuyuki , Tsutsui Hisaya
Published: December 2005

A study of pairs of commutative rings with the same set of prime ideals appears in the literature. In this paper, we investigate pairs of subrings, not necessarily commutative, with a common set of proper ideals.
An age‐dependent population equation with diffusion and delayed birth process
Authors: Fragnelli G.
Published: December 2005

We propose a new age‐dependent population equation which takes into account not only a delay in the birth process, but also other events that may take place during the time between conception and birth. Using semigroup theory, we discuss the well posedness and the asymptotic behavior of the solution.
On Wk,p‐manifolds and Wk,p‐surfaces for analysis of the convergence of mesh‐based approximation
Authors: Scully Kevin
Published: December 2005

To categorize the convergence properties of mesh‐based approximations to manifolds and surfaces, this paper defines these approximations as “Wk,p‐manifolds” and “Wk,p‐surfaces.” In particular, this paper examines the importance of these classifications in the convergence in L1‐norm of interpolants, built on the approximate manifold or surface, of functions defined on the approximated manifold or surface. To provide context, the applicability of an interpolation framework established by Nédélec involving the convergence of metric determinants is examined. An extension of Nédélec′s framework to Wk,p‐surfaces is presented.
Magneto‐thermoelastic waves in a perfectly conducting elastic half‐space in thermoelasticity III
Authors: Roychoudhuri S. K. , Bandyopadhyay Nupur
Published: December 2005

The propagation of magneto‐thermoelastic disturbances in an elastic half‐space caused by the application of a thermal shock on the stress‐free bounding surface in contact with vacuum is investigated. The theory of thermoelasticity III proposed by Green and Naghdi is used to study the interaction between elastic, thermal, and magnetic fields. Small‐time approximations of solutions for displacement, temperature, stress, perturbed magnetic fields both in the vacuum and in the half‐space are derived. The solutions for displacement, temperature, stress, perturbed magnetic field in the solid consist of a dilatational wave front with attenuation depending on magneto‐thermoelastic coupling and also consists of a part diffusive in nature due to the damping term present in the heat transport equation, while the perturbed field in vacuum represents a wave front without attenuation traveling with Alfv′en acoustic wave speed. Displacement and temperatures are continuous at the elastic wave front, while both the stress and the perturbed magnetic field in the half‐space suffer finite jumps at this location. Numerical results for a copper‐like material are presented.
Construction of axisymmetric steady states of an inviscid incompressible fluid by spatially discretized equations for pseudo‐advected vorticity
Authors: Nishiyama Takahiro
Published: December 2005

An infinite number of generalized solutions to the stationary Euler equations with axisymmetry and prescribed circulation are constructed by applying the finite difference method for spatial variables to an equation of pseudo‐advected vorticity. They are proved to be different from exact solutions which are written with trigonometric functions and a Coulomb wave function.
A note on a multiplier of the Norlund means and convex maps of the unit disc
Authors: Ali Ziad S.
Published: December 2005

Important and interesting results which are already known such as those by Pólya and Schoenberg in (1958), Başgöze et al. in (1970), and Ali in (1973), and which are related to convex maps of the unit disc are presented in this note by a more general, unified, and different method. The method considers the product of a nontrivial multiplier with the Norlund means, and shows how the known results indicated above are reproduced again as special cases.
Experimental and Numerical Investigations of a FlexibleRotor on Flexible Bearing Supports
Authors: Sinou J.-J. , Villa C. , Thouverez F.
Published: December 2005

The main goal of this paper is to study, numerically and
experimentally, the effects of the bearing support flexibility on
the rotor dynamic and the first forward and backward critical
speeds. The test rig which is used in this study has been
developed and built at the École Centrale de Lyon (France).
This flexible rotor, supported by two rolling bearings on flexible
supports, is used for three configurations of the flexible
supports. The support characteristics are determined
experimentally by performing static tests. Moreover, a finite
element model of this flexible rotor is presented which consists
of a rigid disk on a flexible shaft supported by two bearing
supports. On the basis of measured frequency response functions
for various rotational speeds, eigenfrequencies and the associated
Campbell diagram from the numerical model and the related
experimental results for the flexible rotor are discussed. The
comparison of these experimental and numerical tests are used in
order to update the finite element model and the associated moment
stiffness of the two rolling bearings for the three configurations
of interest.
Development and Design of a Centrifugal Compressor Volute
Authors: Xu Cheng , Müller Michael
Published: December 2005

The volute is one of the key components of a
centrifugal compressor. The design of the volute not only impacts
the compressor efficiency but also influences the operating
range. The detailed flow simulation presented here helps to
better understand the volute flow mechanisms and provide design
guidance in volute design to meet performance goals. In this
study, the viscous Navier‐Stokes equations are used to simulate
the flow inside the vaneless diffuser and volute. The detailed
flow structures for different volute tongue geometries are
studied in detail. The numerical calculations are compared with
experimental data and good agreement is found. The results also
suggest direction for further investigations in volute design.
Investigation of the Optimum Clocking Position in a Two‐Stage Axial Turbine
Authors: Bohn Dieter , Ausmeier Sabine , Ren Jing
Published: December 2005

A frozen rotor approach in a steady
calculation and a sliding mesh approach in an unsteady simulation
are performed in a stator clocking investigation. The clocking is
executed on the second stator in a two‐stage axial turbine over
several circumferential positions. Flow field distributions as
well as the estimated performances from two approaches are
compared with each other. The optimum clocking positions are
predicted based on the estimated efficiency from the two
approaches. The consistence of the optimum clocking positions is
discussed in the paper. The availability and the limit of the
frozen rotor approach in predicting the optimum clocking position
is analyzed. It is concluded that the frozen rotor approach is
available to search the optimum clocking position in the
preliminary design period, although it misses some features of the
unsteady flow field in the multistage turbines.
Identifying and Minimising Uncertainty for ExperimentalJournal Bearing Studies
Authors: Wale G. D. , Mba D.
Published: December 2005

Over the last few decades, different experimental
methods, with varying forms of data analysis, have been employed
on a wide range of journal bearing types. Under these
circumstances, it is not surprising that the results presented,
and their accuracy, are subject to varying scatter. Many of the
assessments have been rather imprecise, often using unquantified
statements such as “generally good agreement with predictions.”
Most authors seem to have accepted that the appreciable scatter of
results, especially in the dynamic oil film coefficients, was
inevitable. Uncertainty is defined as the estimate of the errors.
Note that the estimate may often be too optimistic
because some sources of error have not been identified. This paper
highlights sources of error for experimental journal studies,
including some associated with the measurement system and physical
misalignment. It is intended that this paper presents a coherent
source of information on best practice in the field of
experimental bearing research, offering a clearly prescribed
methodology to estimate uncertainty and reduce error. The results
of calculations of the sensitivity of the dynamic
bearing coefficients to experimental errors in some commonly used
rig configurations are presented. It is shown that one of the
excitation schemes gives significantly lower sensitivity, but even
this scheme has quite high sensitivity to measurement errors,
especially phase. In conclusion, some of the critical precautions
in the search for good quality results for experimental journal
bearing studies are described.
The Computation of Flow and Heat Transfer through an OrthogonallyRotating Square‐Ended U‐Bend Using Low‐Reynolds‐Number Models
Authors: Nikas Konstantinos-Stephen P. , Iacovides Hector
Published: December 2005

We present computations of heat and fluid flow through a square‐ended U‐bend that rotates about an axis normal to both the main flow direction and also the axis of curvature. Two‐layer and low‐Reynolds‐number mathematical models of turbulence are used at effective‐viscosity (EVM) level and also at second‐moment‐closure
(DSM) level. Moreover, two length‐scale correction terms to the dissipation rate of turbulence are used with the low‐Re models, the original Yap term, and a differential form that does not require the wall distance (NYap). The resulting predictions are compared with available flow and heat transfer measurements of water. While the main flow features are well reproduced by all models, the development of the mean flow within and just after the
bend is better reproduced by the low‐Re models. Turbulence levels within the rotating U‐bend are underpredicted, but DSM models produce a more realistic distribution. Along the leading side, all models overpredict heat transfer levels just after the bend. Along the trailing side, the heat transfer predictions of the low‐Re DSM with the NYap, are close to the measurements.
Numerical Modelization of the Flow in Centrifugal Pump: VoluteInfluence in Velocity and Pressure Fields
Authors: Asuaje Miguel , Bakir Farid , Kouidri Smaïne , Kenyery Frank , Rey Robert
Published: December 2005

A 3D‐CFD simulation of the impeller and volute of a
centrifugal pump has been performed using CFX codes. The pump has
a specific speed of 32 (metric units) and an outside impeller
diameter of 400 mm. First, a 3D flow simulation for the
impeller with a structured grid is presented. A sensitivity
analysis regarding grid quality and turbulence models were also
performed. The final impeller model obtained was used for a 3D
quasi‐unsteady flow simulation of the impeller‐volute stage. A
procedure for designing the volute, the nonstructured grid
generation in the volute, and the interface flow passage between
the impeller and volute are discussed. This flow simulation was
carried out for several impeller blades and volute tongue relative
positions. As a result, velocity and pressure field were
calculated for different flow rates, allowing to obtain the radial
thrust on the pump shaft.
Investigation of the Unsteady Flow Generated byan Axial Fan: Experimental Testing andSimulations
Authors: Amano R. S. , Lee E. K. , Xu C. , Xie Jianhui
Published: December 2005

The unsteady flow measurement of a large axial fan with diameter 1.829m (6 ft) has been carried out. The complex flow field generated by the fan is investigated through experimental testing and CFD/FEA simulation. The results presented in this paper can be divided into three parts. The first part consists of the experimental description of the test facility, velocity measurement, flow‐field visualization, and stress/strain analysis of the fan blades. The second part consists of the CFD simulation of the flow field. Simulation is carried out to analyze
the flow pattern with and without a radiator attached to the fan casing. The results presented in this paper can be used as a reference for axial fan performance improvement in the future.
Stability on coupling SIR epidemic model with vaccination
Authors: Liu Helong , Xu Houbao , Yu Jingyuan , Zhu Guangtian
Published: December 2005

We develop a mathematical model for the disease which can be
transmitted via vector and through blood transfusion in host
population. The host population is structured by the chronological
age. We assume that the instantaneous death and infection rates
depend on the age. Applying semigroup theory and so forth, we
investigate the existence of equilibria. We also discuss local
stability of steady states.
Potential flow of a second‐order fluid over a tri‐axial ellipsoid
Authors: Viana F. , Funada T. , Joseph D. D. , Tashiro N. , Sonoda Y.
Published: December 2005

The problem of potential flow of a second‐order fluid around an ellipsoid is
solved, and the flow and stress fields are computed. The flow fields are determined by the harmonic
potential but the stress fields depend on viscosity and the parameters of
the second‐order fluid. The stress fields on the surface of a tri‐axial
ellipsoid depend strongly on the ratios of principal axes and are such as to
suggest the formation of gas bubble with a round flat nose and
two‐dimensional cusped trailing edge. A thin flat trailing edge gives rise
to a large stress which makes the thin trailing edge thinner.
Dynamic model of multi‐rigid‐body systems based on particle dynamics with recursive approach
Authors: Attia Hazem Ali
Published: December 2005

A dynamic model for multi‐rigid‐body systems which consists of
interconnected rigid bodies based on particle
dynamics and a recursive approach is presented. The method uses the concepts of
linear and angular momentums to generate the rigid body equations
of motion in terms of the Cartesian coordinates of a dynamically
equivalent constrained system of particles, without introducing
any rotational coordinates and the corresponding rotational
transformation matrix. For the open‐chain system, the equations of
motion are generated recursively along the serial chains. A
closed‐chain system is transformed to open‐chain by cutting
suitable kinematical joints and introducing cut‐joint constraints.
An example is chosen to demonstrate the generality and simplicity
of the developed formulation.
Regularization method for parabolic equation with variable operator
Authors: Burmistrova Valentina
Published: December 2005

Consider the initial boundary value problem for the
equation ut = −L(t)u, u(1) = w on an interval [0, 1] for t > 0, where w(x) is a given function in L2(Ω) and Ω is a bounded domain in ℝn with a smooth boundary ∂Ω. L is the unbounded, nonnegative operator in
L2(Ω) corresponding to a selfadjoint, elliptic boundary
value problem in Ω with zero Dirichlet data on
∂Ω. The coefficients of L are assumed to be smooth
and dependent of time. It is well known that this problem is
ill‐posed in the sense that the solution does not depend
continuously on the data. We impose a bound on the solution at
t = 0 and at the same time allow for some imprecision in the data.
Thus we are led to the constrained problem. There is built an
approximation solution, found error estimate for the applied
method, given preliminary error estimates for the approximate
method.