bluuebunny/crossref_metadata_2025 huggingface dataset:
Canine Salmonellosis
Authors: Thompson H. , Wright N. G.
Published: May 2008

Abstract— —There have been numerous reports of the isolation of Salmonellae organisms from the faeces of dogs [Galton, et al. (1952); Cruickshank and Smith (1949)]. There is little information, however, on the pathology of canine salmonellosis; indeed, the great majority of reported cases were clinically normal. This communication describes the isolation of 3 strains of Salmonellae and the pathology associated with fatal disease in young dogs.

Three different serotypes of Salmonellae were isolated from four cases of fatal disease in pups. The main pathological changes described were fibrinous pneumonia and necrotising hepatitis. A striking similarity was noted with the gross postmortem findings in two of the cases to these found in acute ICH infection.

Résumé— —Plusieurs chercheurs ont pu isoler des salmonella dans les fèces de chien (Galton et coll., 1952; Cruikshank et Smith, 1949). On possède cependant très peu de données sur la pathologie de la salmonellose canine; dans la grande majorité des cas signalés, les sujets atteints étaient cliniquement normaux. La présente communication porte sur trois souches de salmonella isolées par l'auteur et sur la pathologie de la tnaladie sous sa forme mortelle chez le sujet jeune.

Zusammenfassung— —Über die Isolierung von Salmonellae‐Organismen aus dem Faeces von Hunden gibt es zahlreiche Berichte (Galton u. Mab. [1952]; Cruickshank und Smith [1949]). Es liegen jedoch wenige Infbrmationen iiber die Pathologie der Hunde‐Salmonellose vor; die grosse Mehrzahl der Berichstfälle war sogar klinisch normal. Die vorliegende Mitteilung beschreibt die Isolierung von drei Salmonellenstämmen und die Pathologie tödlich verlaufender Erkrankungen junger Hunde.
Feline Leukaemia (Lymphosarcoma) Symposium 3 Some Comparative Aspects of Leukaemia in Man and Animals with Particular Reference to Lymphosarcoma*
Authors: Owen L. N.
Published: May 2008

A review of recent advances made in the study of lymphosarcoma in man and animals has been made. Some aspects of leukaemia are also described.
Intraocular Malignant Melanoma in Domestic Cats*
Authors: Bellhorn R. W. , Henkind P.
Published: May 2008

Abstract— —Eight cases of intraocular malignant melanoma in domestic cats are presented and compared to these tumors in the dog and the human. The significance of the origin of all 8 cases within the anterior uvea and its relationship to vascular factors is discussed.

Résumé— —On présente 8 cas de mélanome malin intra‐oculaires chez des chats domestiques et on les compare aux mêmes tumeurs observées chez le chien et l'homme. On discute la signification de l'origine dans l'uvée antérieure dans ces 8 cas et les rapports avec les facteurs vasculaires.

Zusammenfassung— —Acht Fälle von intraocularem malignem Melanom bei Hauskatzen werden beschrieben und mit diesen Tumoren beim Hund und beim Menschen verglichen. Die Signifikanz des Ursprungs aller acht Fälle innerhalb der Uvea anterior und seine Beziehung zu Gefässfaktoren werden besprochen.
The Susceptibility of Six‐Week old Puppies to Canine Herpes Virus
Authors: Wright N. G. , Cornwell H. J. C.
Published: May 2008

Abstract— —Twenty‐two susceptible six‐week old puppies were given canine herpesvirus by various routes. In contrast to the generalised haemorrhagic and necrotising disease in infant puppies, the infection was extremely mild and only a few cellular foci were found in the lungs, kidneys and conjunctiva.

Résumé— —Vingt deux chiots “susceptibles”, âgés de 6 semaines ont reçu le virus herpétique canin par des voies d'administration diverses. Contrairement à la forme hémorragique et nécrosante observéd chez les jeunes chiens, l'infection a été très 1égère et on n'a trouvé que quelques foyers cellulaires dans les poumons les reins et au niveau de la conjonctive.

Zusammenfassung— —Zweiundzwanzig empfindliche, sechs Wochen alte Hunde erhielten HerpesVirus des Hundes auf verschiedenen Wegen. Im Gegensatz zu der generalisierten hämorrhagischen und nekrotisierenden Erkrankung bei neugeworfenen Hunden war die Infektion durch äusserst milden Verlauf gekennzeichnet, und es fanden sich nur einige wenige celluläre Foci in der Lunge, den Nieren und der Bindehaut.
The Femoral Head Prosthesis and the Dog
Authors: HUTTON W. C. , ENGLAND J. P. S.
Published: May 2008

Abstract— —Six dogs had stainless steel femoral head prostheses inserted into their ‘left hip joint’. This paper reports: (1) a method of implanting the prosthesis; (2) the clinical suitability of the shape of the prosthesis, and (3) the use of a technique for comparing post‐operative against pre‐operative gait characteristics, by determining the forces exerted by the pad and the ground.

Résumé— —‐L'auteur a effectué, chez six chiens, le remplacement du la tête de fémur de la hanche gauche par une prothèse en acier inoxydable. La communication porte sur les questions suivantes: méthode propre à I'implantation de la prothèse; observations sur la forme de la prothèse, du point de we clinique; technique permettant de comparer les caractérestiques de la démarche avant et après l'opération, grâce à la mesure de l'effort exercé par la patte du chien et de la réistance du sol.

Zusammenfassung—Sechs Hunden wurden am linken Hüftgelenk Oberschenkelkopfprothesen aus rostfreiem Stahl eingesetzt. Der Artikel berichtet über (1) eine Methode, die Prothese anzubringen; (2) die klinische Zweckdienlichkeit der Prothese und (3) eine Methode, die Eigenschaften der Gangart vor und nach der Operation durch Bestimmung der von der Pfote und dem Boden bewirkten Kräfte zu vergleichen.
The Pathology of Unilateral Pyometra in the Bitch
Authors: Whitney J. C.
Published: May 2008

Abstract— —Twelve cases of Unilateral Pyometra are described with particular reference to the pathology of the genital tract.

As a result of this study, it was concluded that the disparity in size between the two uterine horns was due to interference with drainage from one horn. The causes of obstruction of the uterine lumen are discussed, in particular, torsion of the uterus and stenosis of the lumen which is of significance in all forms of pyometra.

One case that might be described as true Unilateral Pyometra was observed.
Observations based upon the Surgical Repair of 106 Cases of Anterior Cruciate Ligament Rupture
Authors: Singleton W. B.
Published: May 2008

Abstract— Points in relation to anterior cruciate ligament rupture are considered in the light of 106 clinical cases involving ninety‐eight dogs. Data is given regarding breed age and sex of animals in the series as well as observations on arthritic changes associated with this injury. A case is made for surgical repair in view of clinical and experimental findings and the author's technique for re‐stabilization is described.

Resumé— n considère les circonstances d'apparition de la rupture du ligament croisé antérieur du chien à la lumière de 106 cas cliniques portant sur 98 chiens. On rapporte des données concernant la race, l'âge et le sexe des animaux de ce groupe, aussi bien que les observations concernant les modifications articulaires associées à cette affection. Une place est faite aux réparations chirurgicales a la lumière des observations cliniques et expérimentales et la technique de réduction qu'utilisent les auteurs des décrite.

Zusammenfassung— Gesichtspunkte, die in Beziehung zum Riss des vorderen Kreuzbandsstehen, werden an Hand von 106 klinischen Fällen, die 98 Hunde betreffen, besprochen. Es werden Daten des Alters und Geschlechts der Tiere sowie Beobachtungen arthritischer Veränderungen im Zusam‐menhang mit dieser Verietzung mitgeteilt. Klinische und experimentelle Ergebnisse sprechen für einen chirurgischen Eingriff, und die Technik des Auton für die Restabilisierung wird beschreiben.
Some Observations on the Occurance of Legg‐Calvé‐Perthes' Disease (Coxaplana) in the Dog, and an Evaluation of Excision Arthroplasty as a Method of Treatment
Authors: Lee R. , Fry P. D.
Published: May 2008

Abstract— A survey of the cases of Legg‐Calvé‐Perthes' Disease (L.C.P.) in the dog seen at the Glasgow University Veterinary Hospital over a period of 13 years (1955–1968) is reported. Breed, sex and leg incidence are recorded, and the age at which clinical signs were first noted, were assessed. An evaluation of the results of treatment of 50 cases treated medically and 65 cases treated by excision arthroplasty is presented. These results indicate surgical treatment achieves significantly better results, together with a much shorter recovery period.

Résumé— On présente une revue des cas de Maladie de LEGG‐CALVE‐PERTHES (coxa plana) chez le chien, qui ont été observés à I'Hôpital Vétérinaire de 1'Université de Glasgow pendant une période de 13 ans (1955–1968). On a relevÉ la fréquence en fonction de la race, du sexe et du membre atteint, ainsi que l'âge auquel les signes cliniques ont été notés pour la première fois.

On présente une appréciation des résultats du traitement de 50 cas traités médicalement, et de 65 cas traités par exérèse suivie d'une arthroplastie. Ces résultats indiquent que le traitement chirurgical permet d'obtenir des résultats significativement meilleurs en même temps qu'une guérison plus rapide.

Zusammenfassung— Es wird eine Übersicht der Fälle von Legg‐Calvé‐Perthesscher Krankheit (LCP) beim Hunde gegeben, die in einem Zeitraum von dreizehn Jahren (1955–1968) im Veterinary Hospital der Glasgow University beobachtet wurden. Rasse, Geschlecht und Häufigkeit werden angeführt, ebenso das Alter, in dem klinische Anzeichen zuerst auftraten.

Die Ergebnisse von 50 Fällen konservativer Behandlung und von 65 Fällen von Excisionsarthro‐plasie werden mitgeteilt. Diese Ergebnisse zeigen, dass mit der chirurgischen Behandlung wesentlich bessere Resultate erzielt werden und die Wiederherstellungszeit bedeutend verkürzt wird.
Effect of Estradiol, Testosterone, Cortisone Acetate, Somatotropin, Thyrotropin and Parathyroid Hormone on the Lumbar Intervertebral Disc in Growing Dogs*
Authors: Paatsama S. , Rissanen P. , Rokkanen P.
Published: May 2008

The effect of estradiol, testosterone, cortisone acetate, somatotropin, thyro‐tropin and parathyroid hormone on the 2nd lumbar intervertebral disc in 18 growing dogs of non‐chondrodystropic breeds was investigated. Thirteen dogs aged one week to ten months were used as controls. Five of these were of the same litters as the hormone treated dogs. The results were estimated histologically and histochemically. Changes in the annulus fibrosus were observed especially in the groups treated with estradiol, testosterone, thyrotropin and to a lesser extent in the groups treated with somatotropin and cortisone acetate. Especially with the larger doses, the metachromasia of the intercellular substance increased, the structure became looser, fragmentation and homogenization occurred.
Lingual abscesses in three dogs
Authors: VonDoernberg M. C. , Peeters M. E. , TerHaar G. , Kirpensteijn J.
Published: May 2008

Lingual abscessation is a rare condition in dogs. Very little information is available on the diagnosis and treatment of lingual abscesses in the major surgical textbooks and current veterinary literature. The common clinical signs of lingual abscesses are macroglossia, hypersalivation and a reluctance to open the mouth, but these can vary depending on the time course of the disease and the location of the abscess. This article presents three cases of tongue abscess in the dog outlining treatment and outcomes. A thorough diagnostic work up, consisting of anamnesis, clinical and haematological examinations, oral inspection under sedation and the use of diagnostic imaging techniques should be mandatory before surgical exploration of the abscess. Surgery is followed by drainage and systemic antibiotics, complemented by systemic fluid support and pain management. Conservative management of lingual abscesses can be fatal. Sharp trauma from an unknown object is suspected to be the underlying cause for the abscesses in the present cases.
Magnetic resonance imaging findings in acute canine distemper virus infection
Authors: Bathen‐Noethen A. , Stein V. M. , Puff C. , Baumgaertner W. , Tipold A.
Published: May 2008

Demyelination is the prominent histopathological hallmark in the acute stage of canine distemper virus infection. Magnetic resonance imaging is an important diagnostic tool in human beings to determine demyelination in the brain, for example in multiple sclerosis. Five young dogs with clinically suspected canine distemper virus infection were subjected to magnetic resonance imaging of the brain and histopathological and immunohistochemical examinations. Hyperintense lesions and loss of contrast between grey and white matter were detected in T2‐weighted images in the cerebellum and/or in the brainstem of three dogs, which correlated with demyelination demonstrated in histopathological examination. Furthermore, increased signal intensities in T2‐weighted images were seen in the temporal lobe of four dogs with no evidence of demyelination. Magnetic resonance imaging seems to be a sensitive tool for the visualisation of in vivo myelination defects in dogs with acute canine distemper virus infection. Postictal oedema and accumulation of antigen positive cells have to be considered an important differential diagnosis.
Glutamate racemase as a target for drug discovery
Authors: Fisher Stewart L.
Published: May 2008

The bacterial cell wall is a highly cross‐linked polymeric structure consisting of repeating peptidoglycan units, each of which contains a novel pentapeptide substitution which is cross‐linked through transpeptidation. The incorporation ofd‐glutamate as the second residue is strictly conserved across the bacterial kingdom. Glutamate racemase, a member of the cofactor‐independent, two‐thiol‐based family of amino acid racemases, has been implicated in the production and maintenance of sufficientd‐glutamate pool levels required for growth. The subject of over four decades of research, it is now evident that the enzyme is conserved and essential for growth across the bacterial kingdom and has a conserved overall topology and active site architecture; however, several different mechanisms of regulation have been observed. These traits have recently been targeted in the discovery of both narrow and broad spectrum inhibitors. This review outlines the biological history of this enzyme, the recent biochemical and structural characterization of isozymes from a wide range of species and developments in the identification of inhibitors that target the enzyme as possible therapeutic agents.
Community structure and antibiotic production of Streptomyces nodosus bioreactors cultured in liquid environments
Authors: Pereira Tanya , Nikodinovic Jasmina , Nakazono Chojin , Dennis Gary R. , Barrow Kevin D. , Chuck Jo‐Anne
Published: May 2008

Immobilized bacteria are being assessed by industry for drug delivery, novel fermentation systems and the protection of organisms in harsh environments. Alginate bioreactors containing Streptomyces nodosus were examined for community structure, cell viability and amphotericin production under different growth conditions. When cell proliferation was encouraged, substrate hyphae were found inside the alginate matrix and within multicellular projections on the surface of the capsule. The periphery of these projections had erect and branched hyphae, morphologically identical to aerial hyphae. Antibiotic production from immobilized organisms was assessed using conditioned culture medium to eliminate the emergence of a free‐dwelling population. These organisms sporulated with reduced antibiotic production compared with free‐dwelling cultures. The commitment to sporulate was independent of a surface but dependent on community size and nutritional status. This is the first report of the sporulation of S. nodosus in liquid cultures and description of the multicellular community the organism adopts at a solid–liquid interface.
Isolation and characterization of polymorphic microsatellite loci for the horn fly, Haematobia irritans (L.) (Diptera: Muscidae)
Authors: DA ROSA ALINE COELHO , LESSINGER ANA CLÁUDIA , DE AZEREDO‐ESPIN ANA MARIA LIMA , TORRES TATIANA TEIXEIRA
Published: May 2008

The horn fly, Haematobia irritans (L.) (Diptera: Muscidae), is a cosmopolitan livestock pest that has caused a great negative impact on the animal production sector throughout the world. Here, we describe 10 polymorphic microsatellite loci isolated from H. irritans. The number of alleles found ranged from two to eight per locus and the expected heterozygosity from 0.1421 to 0.7702. These loci are potentially useful for the fine‐scale genetic characterization of horn fly populations and provide fundamental information for pest management and planning of control programs.
New microsatellite loci isolated from the field cricket Gryllus bimaculatus characterized in two cricket species, Gryllus bimaculatus and Gryllus campestris
Authors: BRETMAN AMANDA , DAWSON DEBORAH A. , HORSBURGH GAVIN J. , TREGENZA TOM
Published: May 2008

We have developed a new set of 27 polymorphic markers for each of two cricket species, Gryllus bimaculatus and Gryllus campestris. Initially, 14 published G. bimaculatus loci were tested in G. campestris; however, only five loci were polymorphic. Therefore, we isolated an additional 50 new microsatellite loci from G. bimaculatus and tested these in both species. In a minimum of 20 individuals, 27 of the new loci were polymorphic in G. bimaculatus and 25 in G. campestris.
Microsatellite markers for the red band needle blight pathogen, Dothistroma septosporum
Authors: BARNES I , CORTINAS M. N , WINGFIELD M. J , WINGFIELD B. D
Published: May 2008

Twelve microsatellite markers were developed for population analyses of the fungal pathogen, Dothistroma septosporum. Intersimple sequence repeat polymerase chain reaction (ISSR‐PCR) and an enrichment protocol (fast isolation by amplified fragment length polymorphism of sequences containing repeats [FIASCO]) were both used to identify 28 unique microsatellite regions in the genome. From 22 primer pairs designed, 12 were polymorphic. These markers, screened on two populations representing 42 isolates, produced 40 alleles across all loci with an allelic diversity of 0.09–0.76 per locus. Cross‐species amplification showed variable success with Dothistroma rhabdoclinis and Mycosphaerella dearnessi and some sequence variation within isolates of Dothistroma pini. These markers will be used to further study the population structure and diversity of D. septosporum.
Analysis and Interpretation of Stress Fiber Organization in Cells Subject to Cyclic Stretch
Authors: Wei Zhensong , Deshpande Vikram S. , McMeeking Robert M. , Evans Anthony G.
Published: May 2008

Numerical simulations that incorporate a biochemomechanical model for the contractility of the cytoskeleton have been used to rationalize the following observations. Uniaxial cyclic stretching of cells causes stress fibers to align perpendicular to the stretch direction, with degree of alignment dependent on the stretch strain magnitude, as well as the frequency and the transverse contraction of the substrate. Conversely, equibiaxial cyclic stretching induces a uniform distribution of stress fiber orientations. Demonstrations that the model successfully predicts the alignments experimentally found are followed by a parameter study to investigate the influence of a range of key variables including the stretch magnitude, the intrinsic rate sensitivity of the stress fibers, the straining frequency, and the transverse contraction of the substrate. The primary predictions are as follows. The rate sensitivity has a strong influence on alignment, equivalent to that attained by a few percent of additional stretch. The fiber alignment increases with increasing cycling frequency. Transverse contraction of the substrate causes the stress fibers to organize into two symmetrical orientations with respect to the primary stretch direction.
A Structural Model of the Venous Wall Considering Elastin Anisotropy
Authors: Rezakhaniha Rana , Stergiopulos Nikos
Published: May 2008

The three-dimensional biomechanical behavior of the vascular wall is best described by means of strain energy functions. Significant effort has been devoted lately in the development of structure-based models of the vascular wall, which account for the individual contribution of each major structural component (elastin, collagen, and vascular smooth muscle). However, none of the currently proposed structural models succeeded in simultaneously and accurately describing both the pressure-radius and pressure-longitudinal force curves. We have hypothesized that shortcomings of the current models are, in part, due to unaccounted anisotropic properties of elastin. We extended our previously developed biomechanical model to account for elastin anisotropy. The experimental data were obtained from inflation-extension tests on facial veins of five young white New Zealand rabbits. Tests have been carried out under a fully relaxed state of smooth muscle cells for longitudinal stretch ratios ranging from 100% to 130% of the in vivo length. The experimental data (pressure-radius, pressure-force, and zero-stress-state geometries) provided a complete biaxial mechanical characterization of rabbit facial vein and served as the basis for validating the applicability and accuracy of the new biomechanical model of the venous wall. When only the pressure-radius curves were fitted, both the anisotropic and the isotropic models gave excellent results. However, when both pressure-radius and pressure-force curves are simultaneously fitted, the model with isotropic elastin shows an average weighted residual sum of squares of 8.94 and 23.9 in the outer radius and axial force, respectively, as compared to averages of 6.07 and 4.00, when anisotropic elastin is considered. Both the Alkaike information criterion and Schwartz criterion show that the model with the anisotropic elastin is more successful in predicting the data for a wide range of longitudinal stretch ratios. We conclude that anisotropic description of elastin is required for a full 3D characterization of the biomechanics of the venous wall.
Modeling the Mechanics of Tethers Pulled From the Cochlear Outer Hair Cell Membrane
Authors: Schumacher Kristopher R. , Popel Aleksander S. , Anvari Bahman , Brownell William E. , Spector Alexander A.
Published: May 2008

Cell membrane tethers are formed naturally (e.g., in leukocyte rolling) and experimentally to probe membrane properties. In cochlear outer hair cells, the plasma membrane is part of the trilayer lateral wall, where the membrane is attached to the cytoskeleton by a system of radial pillars. The mechanics of these cells is important to the sound amplification and frequency selectivity of the ear. We present a modeling study to simulate the membrane deflection, bending, and interaction with the cytoskeleton in the outer hair cell tether pulling experiment. In our analysis, three regions of the membrane are considered: the body of a cylindrical tether, the area where the membrane is attached and interacts with the cytoskeleton, and the transition region between the two. By using a computational method, we found the shape of the membrane in all three regions over a range of tether lengths and forces observed in experiments. We also analyze the effects of biophysical properties of the membrane, including the bending modulus and the forces of the membrane adhesion to the cytoskeleton. The model’s results provide a better understanding of the mechanics of tethers pulled from cell membranes.
Respiratory System Model for Quasistatic Pulmonary Pressure-Volume (P-V) Curve: Inflation-Deflation Loop Analyses
Authors: Amini R. , Narusawa U.
Published: May 2008

A respiratory system model (RSM) is developed for the deflation process of a quasistatic pressure-volume (P-V) curve, following the model for the inflation process reported earlier. In the RSM of both the inflation and the deflation limb, a respiratory system consists of a large population of basic alveolar elements, each consisting of a piston-spring-cylinder subsystem. A normal distribution of the basic elements is derived from Boltzmann statistical model with the alveolar closing (opening) pressure as the distribution parameter for the deflation (inflation) process. An error minimization by the method of least squares applied to existing P-V loop data from two different data sources confirms that a simultaneous inflation-deflation analysis is required for an accurate determination of RSM parameters. Commonly used terms such as lower inflection point, upper inflection point, and compliance are examined based on the P-V equations, on the distribution function, as well as on the geometric and physical properties of the basic alveolar element.
Resource Letter QEDV-1: The QED vacuum
Authors: Greiner Walter , Schramm Stefan
Published: May 2008

This Resource Letter provides a guide to the literature on vacuum structures and their effects in Quantum Electrodynamics. References to books and journal articles that deal with perturbative vacuum effects as well as nonperturbative processes in extremely strong external fields like spontaneous positron production in strong Coulomb fields are provided.
Dirac–Coulomb energy levels and expectation values
Authors: Adkins Gregory S.
Published: May 2008

The Hellmann–Feynman theorem and the method of generalized virial relations are applied to the Dirac–Coulomb problem to obtain expressions for the energy levels and all expectation values involving integer powers of the radius. These techniques allow many interesting consequences of the theory to be deduced without the need for explicit solutions of the radial wave equation.
Mapping of normal modes by perturbation
Authors: Zypman Fredy R. , Bastuscheck C. Marc
Published: May 2008

To gain physical insight into the modes in a perturbed resonant system we investigate a mechanical cavity perturbed by an additional mass (inclusion). We solve the model exactly and determine the relation between the frequency shift and the inclusion size and location and show that it is possible to use the frequency shift due to a small inclusion to map the spatial distribution of eigenmodes. The relation is analogous to the Bethe–Schwinger expression for the frequency shifts of an electromagnetic mode in a cavity with perturbations.
How students use mathematical resources in an electrostatics context
Authors: Meredith Dawn C. , Marrongelle Karen A.
Published: May 2008

We present evidence that although students’ mathematical skills in introductory calculus-based physics classes may not be readily applied in physics contexts, these students have strong mathematical resources on which to build effective instruction. Our evidence is based on clinical interviews of problem solving in electrostatics, which are analyzed using the framework of Sherin’s symbolic forms. We find that students use notions of “dependence” and “parts-of-a-whole” to successfully guide their work, even in novel situations. We also present evidence that students’ naive conceptions of the limit may prevent them from viewing integrals as sums.
On the steering of sound energy through a supercritical plate by a near-field transducer array
Authors: Anderson Brian E. , Hughes W. Jack , Hambric Stephen A.
Published: May 2008

The ability to direct sound energy through the flexural vibrations of a submerged plate at various angles of incidence using a near-field transducer array is investigated. An alumina bar is placed in front of a one-dimensional, eight-element transducer array, between the array and the water. Operating in a receive mode, data were taken as a function of angle of incidence and compared to data taken without the presence of the alumina bar. The array was also operated in transmit mode and results were compared to corresponding receive mode data, showing that reciprocity holds. Results show that in fact sound energy can be steered through a plate, and that the measurement method used provides a convenient method of measuring the angular dependence of transmission through a plate, including measurements at frequencies above the plate’s critical frequency. Experimental results of sound transmission versus angle of incidence of finite sized plates agree qualitatively with theoretical results from an analysis of the transmission through an unbounded flexible partition.
The high-frequency dispersion coefficient for the Rayleigh velocity in a vertically inhomogeneous anisotropic half-space
Authors: Shuvalov A. L.
Published: May 2008

For an arbitrary anisotropic half-space with continuous vertical variation of material properties, an explicit closed-form expression for the coefficient B of high-frequency dispersion of the Rayleigh velocity vR(ω)≈vR(0)(1+B∕ω) is derived. The result involves two matrices, one consisting of the surface-traction derivatives in velocity and the other of its Wentzel–Kramers–Brillouin coefficients, which are contracted with an amplitude vector of the Rayleigh wave in the reference homogeneous half-space. The “ingredients” are routinely defined through the fundamental elasticity matrix and its first derivative, both taken at v=vR(0) and referred to the surface.
Influence of vehicle color on loudness judgments
Authors: Menzel Daniel , Fastl Hugo , Graf Ralf , Hellbrück Jürgen
Published: May 2008

This experiment investigates the effect of images of differently colored sports cars on the loudness of a simultaneously perceived car sound. Still images of a sports car, colored in red, light green, blue, and dark green, were displayed to subjects during a magnitude estimation task. The sound of an accelerating sports car was used as a stimulus. Statistical analysis suggests that the color of the visual stimulus may have a small influence on loudness judgments. The observed loudness differences are generally equivalent to a change in sound level of about 1dB, with maximum individual differences of up to 3dB.
Multilevel fast multipole algorithm for acoustic wave scattering by truncated ground with trenches
Authors: Tong Mei Song , Chew Weng Cho , White Michael J.
Published: May 2008

The multilevel fast multipole algorithm (MLFMA) is extended to solve for acoustic wave scattering by very large objects with three-dimensional arbitrary shapes. Although the fast multipole method as the prototype of MLFMA was introduced to acoustics early, it has not been used to study acoustic problems with millions of unknowns. In this work, the MLFMA is applied to analyze the acoustic behavior for very large truncated ground with many trenches in order to investigate the approach for mitigating gun blast noise at proving grounds. The implementation of the MLFMA is based on the Nyström method to create matrix equations for the acoustic boundary integral equation. As the Nyström method has a simpler mechanism in the generation of far-interaction terms, which MLFMA acts on, the resulting scheme is more efficient than those based on the method of moments and the boundary element method (BEM). For near-interaction terms, the singular or near-singular integrals are evaluated using a robust technique, which differs from that in BEM. Due to the enhanced efficiency, the MLFMA can rapidly solve acoustic wave scattering problems with more than two million unknowns on workstations without involving parallel algorithms. Numerical examples are used to demonstrate the performance of the MLFMA with report of consumed CPU time and memory usage.
Boundary perturbation methods for high-frequency acoustic scattering: Shallow periodic gratings
Authors: Nicholls David P. , Reitich Fernando
Published: May 2008

Despite significant recent advances in numerical methodologies for simulating rough-surface acoustic scattering, their applicability has been constrained by the limitations of state-of-the-art computational resources. This has been particularly true in high-frequency applications where the sheer size of the full-wave simulations render them impractical, and engineering processes must therefore rely on asymptotic models [e.g., Kirchhoff approximation (KA)]. However, the demands for high precision can make the latter inappropriate, thus efficient, error-controllable methodologies must be devised. This paper presents a computational strategy that combines the virtues of rigorous solvers (error control) with those of high-frequency asymptotic models (frequency-independent computational costs). These methods are based on high-order “boundary perturbations,” which display high precision and unparalleled efficiency. This is accomplished by incorporating asymptotic phase information to effect a significant decrease in computational effort, simultaneously retaining the full-wave nature of the approach. The developments of this contribution are constrained to configurations that preclude multiple scattering; it is further explained how the schemes can be made applicable to general scattering scenarios, though implementation details are left for future work. Even for single-scattering configurations, the approach presented here gives significant gains in accuracy when compared to asymptotic theories (e.g., KA) with modest additional computational cost.
Theory and analysis of frequency-domain photoacoustic tomography
Authors: Baddour Natalie
Published: May 2008

A new frequency-domain approach to photoacoustic tomography has recently been proposed, promising to overcome some of the shortcomings associated with the pulsed photoacoustic approach. This approach offers many of the benefits of pulsed photoacoustics but requires a different set of equations for modeling of the forward and inverse problems due to the longer time scales involved in the optical input signal. The theory of photoacoustic tomography with an optical input that is not necessarily a short pulse is considered in this paper. The full optical, thermal, and acoustic governing equations are derived. A transfer function approach is taken for the solution and analysis of this problem. The results and implications are compared with those of pulsed photoacoustics and traditional ultrasonic diffraction tomography. A Fourier diffraction theorem is also presented, which could be used as a basis for the development of tomographic imaging algorithms.
A method to identify noise-robust perceptual features: Application for consonant /t/
Authors: Régnier Marion S. , Allen Jont B.
Published: May 2008

This study focuses on correlating speech confusion patterns, defined as consonant-vowel confusion as a function of the speech-to-noise ratio, and a model acoustic feature (AF) representation called the AI gram, defined as the articulation index density in the spectrotemporal domain. By collecting many responses from many talkers and listeners, the AF and psychophysical feature (event) is shown to be correlated via the AI-gram model and the confusion matrices at the utterance level, thereby explaining the listener confusion. Consonant /t/ is used as an example to identify its primary robust-to-noise feature, and a precise correlation of the acoustic information with the listeners’ confusions is used to label the event. The main spectrotemporal cue defining the /t/ event is an across-frequency temporal coincidence, wherein frequency spread and robustness vary across utterances, while the event remains invariant. The cross-frequency timing event is shown to be the key perceptual feature for consonants in a vowel following context. Coincidences are found to form the basic element of the auditory object. Neural circuits used for coincidence in binaural processing for localization across ears are proposed to be used within one ear across channels. It is further concluded that the event is based on the audibility of the /t/ burst rather than on any superthreshold property.
Differential contribution of envelope fluctuations across frequency to consonant identification in quiet
Authors: Apoux Frédéric , Bacon Sid P.
Published: May 2008

Two experiments investigated the effects of critical bandwidth and frequency region on the use of temporal envelope cues for speech. In both experiments, spectral details were reduced using vocoder processing. In experiment 1, consonant identification scores were measured in a condition for which the cutoff frequency of the envelope extractor was half the critical bandwidth (HCB) of the auditory filters centered on each analysis band. Results showed that performance is similar to those obtained in conditions for which the envelope cutoff was set to 160Hz or above. Experiment 2 evaluated the impact of setting the cutoff frequency of the envelope extractor to values of 4, 8, and 16Hz or to HCB in one or two contiguous bands for an eight-band vocoder. The cutoff was set to 16Hz for all the other bands. Overall, consonant identification was not affected by removing envelope fluctuations above 4Hz in the low- and high-frequency bands. In contrast, speech intelligibility decreased as the cutoff frequency was decreased in the midfrequency region from 16to4Hz. The behavioral results were fairly consistent with a physical analysis of the stimuli, suggesting that clearly measurable envelope fluctuations cannot be attenuated without affecting speech intelligibility.
Suppression of shocked-bubble expansion due to tissue confinement with application to shock-wave lithotripsy
Authors: Freund Jonathan B.
Published: May 2008

Estimates are made of the effect of tissue confinement on the response of small bubbles subjected to lithotriptor shock pressures. To do this the Rayleigh–Plesset equation, which governs the dynamics of spherical bubbles, is generalized to treat a bubble in a liquid region (blood), which is in turn encased within an elastic membrane (like a vessel’s basement membrane), beyond which a Voigt viscoelastic material models the exterior tissue. Material properties are estimated from a range of measurements available for kidneys and similar soft tissues. Special attention is given to the constitutive modeling of the basement membranes because of their expected importance due to their proximity to the bubble and their toughness. It is found that the highest expected values for the elasticity of the membrane and surrounding tissue are insufficient to suppress bubble growth. The reduced confinement of a cylindrical vessel should not alter this conclusion. Tissue viscosities taken from ultrasound measurements suppress bubble growth somewhat, though not to a degree expected to resist injury. However, the higher reported viscosities measured by other means, which are arguably more relevant to the deformations caused by growing bubbles, do indeed significantly suppress bubble expansion.
Speech detection in spatial and nonspatial speech maskers
Authors: Balakrishnan Uma , Freyman Richard L.
Published: May 2008

The effect of perceived spatial differences on masking release was examined using a 4AFC speech detection paradigm. Targets were 20 words produced by a female talker. Maskers were recordings of continuous streams of nonsense sentences spoken by two female talkers and mixed into each of two channels (two talker, and the same masker time reversed). Two masker spatial conditions were employed: “RF” with a 4ms time lead to the loudspeaker 60° horizontally to the right, and “FR” with the time lead to the front (0°) loudspeaker. The reference nonspatial “F” masker was presented from the front loudspeaker only. Target presentation was always from the front loudspeaker. In Experiment 1, target detection threshold for both natural and time-reversed spatial maskers was 17–20dB lower than that for the nonspatial masker, suggesting that significant release from informational masking occurs with spatial speech maskers regardless of masker understandability. In Experiment 2, the effectiveness of the FR and RF maskers was evaluated as the right loudspeaker output was attenuated until the two-source maskers were indistinguishable from the F masker, as measured independently in a discrimination task. Results indicated that spatial release from masking can be observed with barely noticeable target-masker spatial differences.
Spatial decay, behaviour and space planning models European and International standards on open office acoustics
Authors: Chigot Pierre
Published: May 2008

Recent standardisation work on open plan offices acoustics is characterized by a shift in the way room acoustics is handled. Spatial decay (expressed through rate of spatial decay per doubling of distance, DL2) is preferred to temporal decay (expressed through reverberation time, RT). The complexity of open plan office acoustic design results from the fundamental contradiction of communication and concentration. DL2 reflects better the challenges of sound control in such rooms, which is basically sound propagation control. Beyond, this contradiction, specific space analysis models and tools can help to visualize the acoustic interactions between workstations, teams and departments accommodated in the same room. These models are now ready to be included in standardization work. International technical standard for field measurements of DL2 integrates new descriptive models for open plan office acoustics, taking into account geometric proportions, presence of screens and furniture as well as group behaviour and speech characteristics, such as increased energy contents at low frequencies, voice levels, raised hearing sensitivity at high frequencies. Also, normative guidelines from Netherlands and France integrating this approach will be presented.
Speech Privacy Options for the Open Ceiling Office Environment
Authors: Hougland Dana S.
Published: May 2008

The popularity of the open ceiling and loft office environment continues to grow. The design and effectiveness of sound masking systems in an open office environment are well established for traditional office spaces with acoustically absorptive ceilings systems. Aesthetic preferences for open ceilings with minimal ceiling treatment popular in the creative reuse of older buildings and more minimalist industrial spaces limit the sound masking options available to achieve an acceptable level of speech privacy in an open office environment. Traditional sound masking systems are often subjectively viewed as harsh, unpleasant or visually inappropriate. Several options for alternative designs are evaluated as to the evenness of coverage, effectiveness in achieving an appropriate level of speech privacy, aesthetic integration into the environment and subjective impression of the occupants.
Effective sound masking for speech privacy in open plan offices
Authors: Lewitz Joel
Published: May 2008

For over 30 years acousticians have studied, measured and evaluated open plan offices to improve speech privacy and freedom from distraction. This paper addresses the relative importance of the many factors affecting speech privacy in open plan offices. Adjusting the background noise level at the receiver has proven to be a very powerful and relatively inexpensive method to optimize the acoustical environment in open plan offices. However, sound masking systems are not always properly tuned to achieve the maximum benefit. In this paper, the importance of the shape, smoothness and level of the masking sound spectrum are discussed and demonstrated with case studies. Recent legislation in the U.S., such as the Healthcare Insurance Portability and Accountability Act of 1996, also known as HIPAA, has broadened speech privacy concerns from open plan to closed plan. Sound masking is an attractive option for both configurations. Differences in sound masking design and tuning between open plan and closed plan are explored in this paper.
From backward integration to number-theoretic diffusors
Authors: Schroeder Manfred
Published: May 2008

As a student of physics at Göttingen I was interested in the statistics of electromagnetic resonances in metallic cavities when Erwin Meyer offered me a scholarship in concert-hall acoustics. So we compromised and my thesis eventually appeared under the double heading "The statistical parameters of the frequency responses of large enclosures. Experiments with electromagnetic waves".-After moving to Bell Laboratories in New Jersey, I continued to explore, with Heiner Kuttruft, frequency responses in concert halls by digital simulation, confirming my earlier theory that, above a critical frequency, these responses are just "noise" in the frequency domain. Later I dabbled in anti-feedback circuits and explored, with Ben Logan, artificial reverberation that spawned a minor industry-now dubbed sound scapes (first realized by John Chowning) and virtual reality. Then came the work (with Gerhard Sessler, Jim West, Bishnu Atal and Carol Bird) on Philharmonic Hall in New York, which lead to a new method of measuring reverberation time ("backward" integration) and new surface structures, based on number theory, for better sound diffusion. (The idea came to me during a talk by André Weil on "Gauss Sums" during the celebration of the 200th anniversary of Gauss' birth.)
Experimental analysis of the acoustical behaviour of Musikverein in concert and ballet configurations
Authors: Farina Angelo , Commins Daniel E. , Prodi Nicola
Published: May 2008

Musikverein is among the best concert halls in the world. But the hall is also employed for open-to-the-public ballets. All seats in main stalls are removed, and packed under the wooden floor thanks to a large opening. Detailed acoustical measurements have been performed, with the aim of evaluating the different acoustical behavior with and without the seats. Furthermore, it was attempted to assess the contribution of the air volume under the floor, as a possible "resonant chamber", with volume and absorption significantly different when it is filled with packed seats. The results did show that the main acoustical parameters vary significantly between the "concert" setup and the "public ballet" setup, which is more reverberant, with lesser clarity and more envelopment. Regarding the hypothesis that the volume under the floor has some effect on the acoustical behaviour of the room, the experimental results excluded that this is possible. Furthermore, measurements with accelerometers and pressure/velocity probes did not reveal any difference between the behaviour of the "openable" part of the floor and the surrounding "fixed" floor. So it was concluded that the large difference in acoustical behaviour is simply caused by the removal of the seats, and by changes in fittings of the stage.
Changing seating arrangements of the orchestras - a challenge for the concert hall design
Authors: Meyer Jürgen
Published: May 2008

For the future of concert hall design, two aspects will play an increasing role: the search for new shapes created by the architects and changing seating arrangements preferred by the conductors. Whereas in the last decades, acoustic consultants could assume that e.g. celli and double basses were positioned on the right side of the stage, they will to have consider now that more and more conductors - particularly those of high international reputation - go back to the classic seating arrangement (celli in the center, 2nd violins on the right side. Among others, this distinct tendency leads to the following questions: Which are the tonal (acoustic) advantages of the German seating arrangement and by which roomacoustical means can they been supported? In which directions - seen from the player - exist important reflection areas for timbre, clarity and spaciousness? How should risers on the stage be designed for improving the listeners' sound impression and supporting the musicians' mutual hearing? Do celli and basses need podium areas capable of vibrating? Furthermore, where are critical areas and delay times for generating echos or erroneous localization of French horns or other winds? These questions shall be discussed from physical and psychoacoustic aspects.