bluuebunny/crossref_metadata_2025 huggingface dataset:
Micromotion and Stress Distribution of Immediate Loaded Implants: A Finite Element Analysis
Authors: Fazel A. , Aalai S. , Rismanchian M. , Sadr‐Eshkevari P.
Published: September 2008

Background: Primary stability and micromotion of the implant fixture is mostly influenced by its macrodesign.

Purpose: To assess and compare the peri‐implant stress distribution and micromotion of two types of immediate loading implants, immediate loaded screw (ILS) Nisastan and Xive (DENTSPLY/Friadent, Monnheim, Germany), and to determine the best macrodesign of these two implants by finite element analysis.

Methods: In this experimental study, the accurate pictures of two fixtures (ILS: height = 13, diameter = 4 mm and Xive: height = 13, diameter = 3.8 mm) were taken by a new digital camera (Nikon Coolpix 5700 [Nikon, Japan], resolution = 5.24 megapixel, lens = 8× optical, 4× digital zoom). Following accurate measurements, the three‐dimensional finite element computer model was simulated and inserted in simulated mandibular bone (D2) in SolidWorks 2003 (SolidWork Corp., MA, USA) and Ansys 7.1 (Ansys, Inc., Canonsburg, PA, USA). After loading (500 N, 75° above horizon), the displacement was displayed and von Mises stress was recorded.

Results: It was found that the primary stability of ILS was greater (152 µm) than Xive (284 µm). ILS exhibited more favorable stress distribution. Maximum stress concentration found in periapical bone around Xive (≈30 MPa) was lesser than Nisastan (≈37 MPa).

Conclusions: Macrodesign of ILS leads to better primary stability and stress distribution. Maximum stress around Xive was less.
Histomorphometric Evaluation of a Nanothickness Bioceramic Deposition on Endosseous Implants: A Study in Dogs
Authors: Coelho Paulo G. , Cardaropoli Giuseppe , Suzuki Marcelo , Lemons Jack E.
Published: September 2008

Purpose: The objective of this study was to evaluate the bone response to a nanothickness bioceramic ion beam‐assisted deposition (IBAD) on endosteal implants in a canine model.

Materials and Methods: Alumina‐blasted/acid‐etched (control) and IBAD‐modified (test) implants were characterized by scanning electron microscopy, X‐ray photoelectron spectroscopy + ion beam milling, thin‐film mode X‐ray diffraction, and atomic force microscope. The implants were surgically placed in four dogs' proximal tibiae and remained for 2 and 4 weeks in vivo. Oxytetracycline (10 mg/kg) was administered for bone labeling 48 hours prior to euthanization. Following euthanization, nondecalcified thin sections were prepared for UV and transmitted light microscopy. The amount of bone labeling was evaluated along the length and away from the implant surface by means of a computer software. The % bone‐to‐implant contact (BIC) was determined for each specimen. One‐way analysis of variance at 95% level of significance along with Tukey's post hoc multiple comparisons were utilized for statistical evaluation. The characterization showed Ca‐ and P‐based amorphous coatings with a 20‐ to 50‐nm thickness.

Results: In vivo results showed a significant increase in general and site‐specific (to 0.5 mm from the implant surface) bone activity for the 4‐week test implants compared with the control implants. Bone activity levels decreased as a function of distance from the implant surface for all groups. No significant differences in BIC were observed between groups.

Conclusions: This study showed that both surfaces were biocompatible and osteoconductive and that a time‐dependent increase in osteoactivity occurred around the test implants.
A Restoratively Driven Ridge Categorization, as Determined by Incorporating Ideal Restorative Positions on Radiographic Templates Utilizing Computed Tomography Scan Analysis
Authors: Elian Nicolas , Ehrlich Brian , Jalbout Ziad , Cho Sang‐Choon , Froum Stuart , Tarnow Dennis
Published: September 2008

Background: The introduction of implants into the field of dentistry has revolutionized the way we evaluate edentulous ridges. In an attempt to evaluate the deficient edentulous ridge, numerous classification systems have been proposed. Each of these classification systems implements a different approach for evaluating and planning treatment for the ridge deficiency.

Purpose: The purpose of the present investigation was to propose a restoratively driven ridge categorization (RDRC) for horizontal ridge deformities based on an ideal implant position as determined through implant simulation, utilizing computed tomography (CT) scan images.

Materials and Methods: Radiographic templates were developed to capture the ideal restorative tooth position. Measurements were performed using CT scan software in a cross‐sectional view and by virtual placement of a parallel‐sided implant with a 3.25‐mm diameter.

Results: Edentulous ridges were divided into five groupings: Group I, simulated implants with at least 2 mm of facial bone, accounted for 19.4% of ridges; Group II, simulated implant completely surrounded by bone, with less than 2 mm of facial plate thickness, accounted for 10.4% of ridges; Group III, wherein dehiscences are detected but no fenestrations are present, accounted for 33.3% of ridges; Group IV, wherein fenestrations are detected but no dehiscence is present, accounted for 6.3% of ridges; and Group V, wherein both dehiscences and fenestrations are present, accounted for 30.6% of ridges.

Conclusion: The use of RDRC indicates that a high number of cases in the maxillary anterior area would require augmentation procedures in order to achieve ideal implant placement and restoration.
Comparison of Biomaterial Implants in the Dental Socket: Histological Analysis in Dogs
Authors: Santos Fábio André , Pochapski Márcia Thaís , Martins Marilia Campagnoni , Zenóbio Elton Gonçalves , Spolidoro Luís Carlos , Marcantonio Jr Elcio
Published: September 2008

Background: Bone graft procedures have been used commonly in buco‐maxillo‐facial surgery. For this reason, many researchers have evaluated the bone substitutes.

Purpose: The present study evaluated soft and hard tissue reactions to two different hydroxyapatites HAs (synthetic HA and natural HA) and bioactive glass implanted into the sockets immediately after extraction.

Materials and Methods: First and third upper and lower premolars, on both sides, were extracted from six female dogs. The alveolar sockets were randomly assigned to four groups: Group 1 – control (unfilled), Group 2 – filled with synthetic hydroxyapatite, Group 3 – filled with bovine bone mineral (natural HA), and Group 4 – filled with bioactive glass. The animals were euthanized at 4 weeks (n = 2), 8 weeks (n = 2), and 28 weeks (n = 2) after extraction. The mandible and maxilla of each animal were removed for histological analysis to determine soft tissue reactions, newly formed bone, bone characteristics, and presence or absence of implanted materials.

Results: Most particles of synthetic hydroxyapatite had bone formation on their surface, although some particles showed a layer of fibrous connective tissue. The bovine bone mineral group exhibited particles partially replaced with bone formation. The bioactive glass group showed particles with a thin layer of calcified tissue, but was absent in some specimens, suggesting complete resorption.

Conclusion: All biomaterials had similar behavior. Bovine bone mineral, compared to synthetic hydroxyapatite and bioactive glass, showed a larger number of particles covered with osseous tissue. All biomaterials interfered with the socket repair process.
Novel isoenzyme of 2‐oxoglutarate dehydrogenase is identified in brain, but not in heart
Authors: Bunik Victoria , Kaehne Thilo , Degtyarev Dmitry , Shcherbakova Tatiana , Reiser Georg
Published: September 2008

2‐Oxoglutarate dehydrogenase (OGDH) is the first and rate‐limiting component of the multienzyme OGDH complex (OGDHC) whose malfunction is associated with neurodegeneration. The essential role of this complex in the degradation of glucose and glutamate, which have specific significance in brain, raises questions about the existence of brain‐specific OGDHC isoenzyme(s). We purified OGDHC from extracts of brain or heart mitochondria using the same procedure of poly(ethylene glycol) fractionation, followed by size‐exclusion chromatography. Chromatographic behavior and the insufficiency of mitochondrial disruption to solubilize OGDHC revealed functionally significant binding of the complex to membrane. Components of OGDHC from brain and heart were identified using nano‐high performance liquid chromatography electrospray tandem mass spectrometry after trypsinolysis of the electrophoretically separated proteins. In contrast to the heart complex, where only the known OGDH was determined, the band corresponding to the brain OGDH component was found to also include the novel 2‐oxoglutarate dehydrogenase‐like (OGDHL) protein. The ratio of identified peptides characteristic of OGDH and OGDHL was preserved during purification and indicated comparable quantities of the two proteins in brain. Brain OGDHC also differed from the heart complex in the abundance of the components, lower apparent molecular mass and decreased stability upon size‐exclusion chromatography. The functional competence of the novel brain isoenzyme and different regulation of OGDH and OGDHL by 2‐oxoglutarate are inferred from the biphasic dependence of the overall reaction rate versus 2‐oxoglutarate concentration. OGDHL may thus participate in brain‐specific control of 2‐oxoglutarate distribution between energy production and synthesis of the neurotransmitter glutamate.
Location of the Bombyx mori 175 kDa cadherin‐like protein‐binding site on Bacillus thuringiensis Cry1Aa toxin
Authors: Atsumi Shogo , Inoue Yukino , Ishizaka Takahisa , Mizuno Eri , Yoshizawa Yasutaka , Kitami Madoka , Sato Ryoichi
Published: September 2008

To identify and gain a better understanding of the cadherin‐like receptor‐binding site on Bacillus thuringiensis Cry toxins, it is advantageous to use Cry1Aa toxin, because its 3D structure is known. Therefore, Cry1Aa toxin was used to examine the locations of cadherin‐like protein‐binding sites. Initial experiments examining the binding compatibility for Cry1Aa toxin of partial fragments of recombinant proteins of a 175 kDa cadherin‐like protein from Bombyx mori (BtR175) and another putative receptor for Cry1Aa toxin, aminopeptidase N1, from Bo. mori (BmAPN1), suggested that their binding sites are close to each other. Of the seven mAbs against Cry1Aa toxin, two mAbs were selected that block the binding site for BtR175 on Cry1Aa toxin: 2A11 and 2F9. Immunoblotting and alignment analyses of four Cry toxins revealed amino acids that included the epitope of mAb 2A11, and suggested that the area on Cry1Aa toxin blocked by the binding of mAb 2A11 is located in the region consisting of loops 2 and 3. Two Cry1Aa toxin mutants were constructed by substituting a Cys on the area blocked by the binding of mAb 2A11, and the small blocking molecule, N‐(9‐acridinyl)maleimide, was introduced at each Cys substitution to determine the BtR175‐binding site. Substitution of Tyr445 for Cys had a crippling effect on binding of Cry1Aa toxin to BtR175, suggesting that Tyr445 may be in or close to the BtR175‐binding site. Monoclonal antibodies that blocked the binding site for BtR175 on Cry1Aa toxin inhibited the toxicity of Cry1Aa toxin against Bo. mori, indicating that binding of Cry1Aa toxin to BtR175 is essential for the action of Cry1Aa toxin on the insect.
Secondary structure conversions of Alzheimer’s Aβ(1–40) peptide induced by membrane‐mimicking detergents
Authors: Wahlström Anna , Hugonin Loïc , Perálvarez‐Marín Alex , Jarvet Jüri , Gräslund Astrid
Published: September 2008

The amyloid β peptide (Aβ) with 39–42 residues is the major component of amyloid plaques found in brains of Alzheimer’s disease patients, and soluble oligomeric peptide aggregates mediate toxic effects on neurons. The Aβ aggregation involves a conformational change of the peptide structure to β‐sheet. In the present study, we report on the effect of detergents on the structure transitions of Aβ, to mimic the effects that biomembranes may have. In vitro, monomeric Aβ(1–40) in a dilute aqueous solution is weakly structured. By gradually adding small amounts of sodium dodecyl sulfate (SDS) or lithium dodecyl sulfate to a dilute aqueous solution, Aβ(1–40) is converted to β‐sheet, as observed by CD at 3 °C and 20 °C. The transition is mainly a two‐state process, as revealed by approximately isodichroic points in the titrations. Aβ(1–40) loses almost all NMR signals at dodecyl sulfate concentrations giving rise to the optimal β‐sheet content (approximate detergent/peptide ratio = 20). Under these conditions, thioflavin T fluorescence measurements indicate a maximum of aggregated amyloid‐like structures. The loss of NMR signals suggests that these are also involved in intermediate chemical exchange. Transverse relaxation optimized spectroscopy NMR spectra indicate that the C‐terminal residues are more dynamic than the others. By further addition of SDS or lithium dodecyl sulfate reaching concentrations close to the critical micellar concentration, CD, NMR and FTIR spectra show that the peptide rearranges to form a micelle‐bound structure with α‐helical segments, similar to the secondary structures formed when a high concentration of detergent is added directly to the peptide solution.
Biogeography and Divergence in Guaiacum sanctum (Zygophyllaceae) Revealed in Chloroplast DNA: Implications for Conservation in the Florida Keys
Authors: Dertien Joseph R. , Duvall Melvin R.
Published: September 2008

Guaiacum sanctum (lignumvitae, guayacán) comprises economically important and globally endangered trees endemic to the dry neotropics. These trees were historically over‐harvested and now G. sanctum is among the species listed by IUCN and CITES. Guaiacum sanctum was once found throughout the Florida Keys, but anthropogenic habitat fragmentation and exploitation have left only one significant population, on Lignumvitae Key. The ecology of this population is additionally subject to hurricane‐mediated effects and an endemic parasite. Genetic profiles were determined for the Lignumvitae and putative source populations of G. sanctum to assess variability and to test biogeographic hypotheses. These data were analyzed by phylogenetic and statistical parsimony analyses. The results were most readily interpreted as indicating historical fragmentation followed by long‐term isolation. However, recent dispersal or gene flow could not be entirely excluded. Both types of analyses strongly support a significant genetic divergence between Caribbean and Mexican populations of G. sanctum and also suggest bidirectional dispersal of G. sanctum into Lignumvitae Key from both the Caribbean and Mexico. These results inform the process of restoring G. sanctum in the Keys.
Puzzling X-rays from the new colliding wind binary Wolf–Rayet 65 (WC9d)
Authors: Oskinova L. M. , Hamann W.-R.
Published: September 2008

We report the discovery of variability in the X-ray emission from the Wolf–Rayet type star WR 65. Using archival Chandra data spanning over 5 yr, we detect changes of the X-ray flux by a factor of 3 accompanied by changes in the X-ray spectra. We believe that this X-ray emission originates from wind–wind collision in a massive binary system. The observed changes can be explained by the variations in the emission measure of the hot plasma, and in the different absorption column along the binary orbit. The X-ray spectra of WR 65 display prominent emission features at wavelengths corresponding to the lines of strongly ionized Fe, Ca, Ar, S, Si and Mg. WR 65 is a carbon-rich WC9d star that is a persistent dust maker. This is the first investigation of any X-ray spectrum for a star of this spectral type. There are indications that the dust and the complex geometry of the colliding wind region are pivotal in explaining the X-ray properties of WR 65.
Ultra-high energy cosmic rays, spiral galaxies and magnetars
Authors: Ghisellini G. , Ghirlanda G. , Tavecchio F. , Fraternali F. , Pareschi G.
Published: September 2008

We measure the correlation between the arrival directions of the highest energy cosmic rays detected by the Pierre Auger Observatory with the position of the galaxies in the H i Parkes All-Sky Survey (HIPASS) catalogue, weighted for their H i flux and Auger exposure. The use of this absorption-free catalogue, complete also along the Galactic plane, allows us to use all the Auger events. The correlation is significant, being 86.2 per cent for the entire sample of H i galaxies, and becoming 99 per cent when considering the richest galaxies in H i content or 98 per cent with those lying between 40 and 55 Mpc. We interpret this result as the evidence that spiral galaxies are the hosts of the producers of ultra-high energy cosmic rays and we briefly discuss the classical (i.e. energetic and distant) long gamma-ray burst (GRBs), short GRBs, as well as newly born or late-flaring magnetars as possible sources of the Auger events. With the caveat that these events are still very few, and the theoretical uncertainties are conspicuous, we found that newly born magnetars are the best candidates. If so, they could also be associated with sub-energetic, spectrally soft, nearby, long GRBs. We finally discuss why there is a clustering of Auger events in the direction on the radio galaxy Cen A and an absence of events in the direction of the radio galaxy M87.
EVALUATION OF THIN‐LAYER DRYING MODELS FOR DESCRIBING DRYING KINETICS OF BARBERRIES (BARBERRIES VULGARIS)
Authors: AGHBASHLO MORTAZA , KIANMEHR MOHAMMAD H. , SAMIMI‐AKHIJAHANI HADI
Published: September 2008

Barberry is known as a medicinal and ornamental plant throughout the world. Edible fruit from the barberry is used in medicine to treat liver, neck and stomach cancer, for purification of the blood and for breath freshness. In order to assess and select a suitable form of the drying curve, six different semitheoretical and/or empirical models were fitted to the experimental data. Experiments were performed at air temperatures of 50, 60 and 70C. At each temperature, three air velocity values were selected: 0.5, 1 and 2 m/s. Consequently, of all the drying models, the Page model was selected as the best mathematical model according to R2, χ2 and root mean square error parameters. Constants related to the Page model are reported and regressed against air condition using multiple regression analysis.

PRACTICAL APPLICATION

All commercial flow dryers are designed on thin‐layer drying principles. Thin‐layer drying means to dry as one layer of sample particles or slices. In this paper we present a mathematical model for thin‐layer drying of barberry fruits (moisture ratio against time). Definition of moisture ratio as a function of time and drying condition has many advantages such as (1) easy control of dryer system, (2) lower energy consumption, (3) less thermal damage to the products and (4) lower investment. It is believed that the present study should be useful to people seeking (1) to optimize the design of drying systems and their components, and (2) to identify appropriate applications and optimal configurations for drying systems.
MOISTURE DESORPTION OF PADDY BY TWO DIFFERENT POROUS MEDIA: MATHEMATICAL MODELS AND EXPERIMENTAL DATA
Authors: WIRIYAUMPAIWONG SONGCHAI , RAIKHAM KITTIPORN , YANGVO PANNEE , SOPONRONNARIT SOMCHART
Published: September 2008

The aim of this work was to study the moisture reduction of paddy by two different adsorbents, tapioca flour and rice husk. The effects of the mixed ratio of adsorbent to paddy, the initial moisture content of adsorbent and the number of times of adsorbent replacement on the moisture desorption of paddy, moisture adsorption of adsorbent and milling qualities were investigated. The mathematical models were developed for predicting the moisture desorption of paddy and moisture adsorption of adsorbent. Experimental one‐pass sorption results revealed that the higher mixed ratio and lower initial moisture content of adsorbent provided the higher moisture reduction rate of paddy and gave the higher water adsorption of adsorbent. It was also found that mixed ratio, initial moisture content and the number of times of adsorbent replacement had no obvious effect on percentage of head rice yield and whiteness of milled rice. Page's model was fitted properly with the experimental desorption and adsorption data.

PRACTICAL APPLICATIONS

Adsorption is a useful process in order to maintain some qualities of heat‐sensitive product because it operates at low temperature. Adsorption is a time‐consuming process to remove moisture of adsorbate until its moisture is down to safe storage. This is because drying rate is controlled by diffusion of a product. Slow diffusion rate can prevent the quality loss of product during the drying process. The investigation involving moisture desorption of agricultural products by different kinds of adsorbent will provide more understanding on the mechanism of sorption process.
THERMOPHYSICAL PROPERTIES OF COCONUT WATER AFFECTED BY TEMPERATURE
Authors: FONTAN RAFAEL DA COSTA ILHÉU , SANTOS LEANDRO SOARES , BONOMO RENATA CRISTINA FERREIRA , LEMOS ALANA ROCHA , RIBEIRO RAQUEL PRATES , VELOSO CRISTIANE MARTINS
Published: September 2008

The effect of temperature on the thermophysical properties of coconut water was investigated from 5 to 80C, taking density, Newtonian viscosity, thermal diffusivity and thermal conductivity into consideration, besides specific heat. The validation of existent models of other foodstuffs, as well as the proposal of new models, was also investigated. It was verified that temperature significantly affected these properties, presenting in general a linear behavior, except for Newtonian viscosity, which presented an exponential behavior. Among the existent equations, results from the multiple linear model were appropriated to predict the density, thermal diffusivity and thermal conductivity values, while the model, which depended on solids fraction, was the best one for specific heat value, and the exponential model was the best in relation to Newtonian viscosity values. The proposed models fitted well, and were simple and easy to use.

PRACTICAL APPLICATIONS

Most of the known values of thermophysical properties of fluid foods typically concern products from subtropical and cold areas. Until today, there was little information concerning tropical products such as coconut water. Food composition and temperature are important factors that affect thermal properties. In order to create and adapt specific equipment, optimize processes that involve pumping and heat transfer, contributing to an effective design of food‐processing equipment for tropical fluid foods, it is important to know the factors. Besides, the evaluation of existent models and equations, and the introduction of new equations is important to allow an adequate prediction of studied properties, thus saving time, material and money.
CORROSION AND WEAR PROPERTIES OF MATERIALS USED FOR MINCED MEAT PRODUCTION
Authors: JELLESEN MORTEN S. , HANSEN MIKKEL ØSTERGAARD , HILBERT LISBETH RISCHEL , MØLLER PER
Published: September 2008

The risk of material degradation is present in minced‐meat processing equipment. Corrosion, wear and tribocorrosion properties of commonly used steel materials for such processing equipment are therefore studied in detail. Corrosiveness of minced meat has been evaluated by potentiodynamic measurements. Combined sliding wear and corrosion conditions have been simulated in laboratory using a block‐on‐ring setup allowing for electrochemical measurements. Detailed information concerning the mechanism of possible material degradation is provided by these results, together with microstructural analysis and thermodynamic considerations. Areas of precaution are stated and new material solutions are suggested.

PRACTICAL APPLICATIONS

The presented results show the importance of investigating both corrosion and wear properties of materials used for processing food under tribocorrosive conditions. In meat mincing, the processing materials need to be wear resistant and at the same time corrosion resistant because of possible aggressiveness of the food product and cleaning procedures. The use of laboratory setups has made it possible to investigate a steel containing vanadium‐nitride and carbide phases in respect of both corrosion and wear properties
Association of lens opacities, intraocular straylight, contrast sensitivity and visual acuity in European drivers
Authors: Michael Ralph , Van Rijn Laurentius J. , Van Den Berg Thomas J. T. P. , Barraquer Rafael I. , Grabner Günther , Wilhelm Helmut , Coeckelbergh Tanja , Emesz Martin , Marvan Patrik , Nischler Christian
Published: September 2008

Purpose:  To study the relationship between lens opacity and intraocular straylight, visual acuity and contrast sensitivity.

Methods:  We investigated 2422 drivers in five clinics in different European Union (EU) member states aged between 20 and 89 years as part of a European study into the prevalence of visual function disorders in drivers. We measured visual acuity [Early Treatment Diabetic Retinopathy Study (ETDRS) chart], contrast sensitivity (Pelli–Robson chart) and intraocular straylight (computerized straylight meter). Lens opacities were graded with the Lens Opacities Classification System III (LOCS) without pupillary dilation. Participants answered the National Eye Institute Visual Functioning Questionnaire – 25.

Results:  Intraocular straylight was related more strongly to LOCS score than to both visual acuity and contrast sensitivity. Visual acuity and contrast sensitivity were correlated to each other well, but to intraocular straylight to a much lesser extent. Self‐reported visual quality was best related to contrast sensitivity; night driving difficulty was best related to visual acuity.

Conclusion:  Straylight is found to have added value for visual function assessment in drivers, whereas if visual acuity is known contrast sensitivity has limited added value.
Strain‐Specific Sensitivity Estimates of Mycobacterium avium subsp. paratuberculosis Culture in Greek Sheep and Goats
Authors: Florou M. , Leontides L. , Kostoulas P. , Billinis C. , Sofia M.
Published: September 2008

The requirements for the isolation of Mycobacterium avium subsp. paratuberculosis (Map) may be related to the strain‐type [sheep (S)‐ or cattle (C)‐type] and not to the host. The objective of this paper was to estimate and compare strain‐ and biological sample (faeces or pooled‐tissue) – specific sensitivities (Ses) of two solid culture media, Herrold’s egg yolk medium (HEYM) and Lowenstein–Jensen (LJ) medium, for the isolation of Map from Greek dairy sheep and goats. From 400 faecal samples collected from sub‐clinically infected sheep and goats of four flocks and from 214 pooled‐tissue samples (142 from sheep and 72 from goats) collected, at the abattoir, from >1‐year‐old routinely slaughtered animals, with gross pathology suggestive of paratuberculosis, we isolated 34 Map strains. Of those, by the IS1311 PCR, 18 were categorized into the C‐type and nine into the S‐type; seven were not typed. We used a Bayesian approach to estimate the strain‐specific Ses. SeHEYM‐C‐faecal = 17% (95% credible interval: 7, 40) was higher than SeHEYM‐S‐faecal = 2% (0.3, 11). Also, SeHEYM‐C‐faecal was higher than SeLJ‐C‐faecal = 4% (1, 12). In pooled‐tissue samples, the strain‐specific Ses did not differ between the two media.
Live sound measurements in stadia
Authors: Ahnert Wolfgang , Feistel Stefan , Miron Alexandra Radu , Finder Enno
Published: September 2008

In this presentation, the authors introduce the software-based measuring system EASERA SysTune to be used for measurements by excitation with music or speech signals. It investigates the use of standard signals supplied from a sound system in a stadium in real-time. Using a newly developed program module, live-sound recordings or speech and music signals from a microphone input and from the mixing console can be utilized to obtain impulse response data for further evaluation. New noise suppression methods are presented that allow these impulse responses to be acquired in full-length, even in occupied venues. As case studies, acoustic measurements based on live sound supply are discussed for a soccer stadium. Required measuring conditions and limitations are derived as a result.
A direct inversion scheme to obtain sediment sound speed and density in shallow water
Authors: Becker Kyle M.
Published: September 2008

A simple inversion scheme is described for estimating the sound speed and density in the seabed for Pekeris-type waveguides. At a fixed frequency, input data to the inversion algorithm are discrete values of the phase of the plane wave reflection coefficient at the water/bottom interface. Above the critical angle, the input data are derived from estimates of the horizontal wave numbers for propagating modes in the wave guide. For two or more propagating modes, a linear system of equations is solved directly to determine sound speed and density in the bottom. The approach is strictly only valid for determining properties of the lower half-space in a Pekeris Wave guide. However, in certain circumstances, the approach can be applied to determine properties of the topmost sediment in layered media. The method is demonstrated on a synthetic data set and then applied to data collected at sea. [Work supported by an ONR Ocean Acoustics Entry-Level Faculty Award.]
Analysis of the effect of water column sound speed variation on geoacoustic inversion
Authors: Jiang Yong-Min , Chapman N. Ross
Published: September 2008

Bayesian matched field inversion has been applied on multi-tonal data sets acquired on the New Jersey continental shelf in the SW06 experiment in August, 2006. Since the data sets were collected in a range-dependent environment due to water column sound speed variation, sound speed profile (SSP) was decomposed in terms of empirical orthogonal functions and also inverted in the inversion. This presentation examines the sensitivity of the geoacoustic and geometrical parameters to the shape and the gradient of the sound speed in the thermocline by the interparameter correlation from the inversion. The effects of the SSP on the geoacoustic inversion and source localization are studied through the inversions of measured data at different ranges with/without prior information about geometric parameters in the inversion. Further investigations on the variation of SSP to the sediment sound speed, density, and attenuation at different ranges are carried out by simulations. It is found that the geometric parameters are more sensitive to the SSP than are the geoacoustic parameters in this shallow water environment. [Work supported by ONR.]
Improved perturbative inversion schemes for obtaining bottom geoacoustic properties in shallow water
Authors: Ballard Megan S. , Becker Kyle M.
Published: September 2008

Perturbative schemes using modal wave numbers are used to obtain sound speed in the sediment as a function of depth [S. D. Rajan, et. al., J. Acoust. Soc. Am. 82(3), 998–1017 (1987)]. The inversion algorithm involves solving an ill-posed problem, with regularization and singular-value decomposition used to stabilize the solution, resulting in a smoothed version of the true sound speed profile. However, owing to geological processes, sediments are often better described by layers having distinct properties and are not well represented by a smooth profile. In this work, two new methods are applied to stabilize the solution of the inverse problem, making it possible to resolve discontinuities in the sound speed profile of the sediment. Piecewise polynomial truncated singular value decomposition (PP-TSVD) is used in place of traditional stabilizing methods and is demonstrated to yield better results when a layered model is a reasonable assumption. The results can be further improved using qualitative regularization if prior knowledge of the location of sound speed discontinuities is available. These methods are shown to yield very accurate estimates of the sound speed profile deep into the sediment using very few perturbations to the forward model. [Work supported by NDSEG and ONR.]
Modeling underwater sound propagation from an airgun array using the parabolic equation method
Authors: MacGillivray Alexander
Published: September 2008

A technique for modeling sound propagation from an airgun array using the parabolic equation (PE) method is presented that takes into full account the far-field, angle-dependent directionality pattern of the array. This is achieved by generating a PE starting field for the array by summing together shaded, phase-shifted replicas of the PE self-starter. The array starter has been implemented using the RAM parabolic equation code. Validation comparisons are presented of field predictions generated using the array starter against exact normal mode solutions for an array source computed using ORCA. Examples of synthetic waveform airgun array calculations are also presented. The array starter method can be used to accurately predict pressure waveforms from an airgun array in the ocean environment provided that the modeler knows (or can compute) ‘‘notional’’ far-field source signatures for individual airguns in the array.
Psychoacoustic evaluation of music reproduction in passenger cars
Authors: Fastl Hugo , Ammler Martin , Sulowski Adam
Published: September 2008

A method to assess the quality of music reproduction in passenger cars is developed and evaluated. In essence, the subject sits in a standing car and is presented from a CD music of different genres via the car’s audio system. The subject has to rate different aspects of the performance on a 10 step scale using a PDA. From the ratings, a net like a spider net, with different attributes like natural, squeeking, dull, reverberant, acceptable, good etc. on its rays is constructed. The goal is a net with a large area, i.e. as many as possible of the attributes should attain the maximum rating. Examples from a pilot study are given for car audio systems of different sophistication, and aspects like gender differences or possible biases towards a product will be discussed.
Changing the paradigm of practice rooms and music teachers coaching studios
Authors: Freiheit Ron
Published: September 2008

For years the image of practice rooms for many musicians meant playing in places that at times resembled (and sometimes were, in fact) closets. They served the function by creating individual places to practice, but were usually less than desirable due to the internal acoustics provided. The same paradigm has held true for most music teachers coaching studios. Time spent with the teacher was invaluable for improving one’s craft, however the acoustics were constrained the rooms physical dimensions, construction materials and room furnishings. With the advent of DSP, these spaces can now provide a variety of acoustic environments for practice and coaching. Integrated into the latest DSP technology is the ability to provide concurrent recording capability, enabling immediate review of the musician’s performance. In the coaching studio, it is especially effective when the student can quickly hear a specific point the teacher is making. New technology accomplishes this more quickly than with past recording methods. The net result of these additional tools is to accelerate the potential learning experience for the musician.
Psychoacoustics of non-real spaces
Authors: Ortallono Sam
Published: September 2008

Psychoacoustics of non-real spaces, modern recording, and mixing techniques provide the opportunity to create acoustic phenomena that do not exist in the real world. This presentation will discuss how recorded music has been manipulated and try to understand what people think they hear and why. Through a combination of recent original recordings and classic records, investigations can be made into how processed sound can disorient, surprise, or please the listener. In the studio, compressors, gates, delays, and artificial reverbs are employed to create unnatural soundscapes, yet the mind still applies the rules that have been learned in everyday life. Such impossibilities as backward sounds and multiple sources will also be considered. Finally, some speculation can be made as to why these records seem to sound even better than the real thing.
Acoustic investigations of concert halls for rock music
Authors: Adelman-Larsen Niels W. , Thompson Eric R. , Gade Anders C.
Published: September 2008

Objective measurement data and subjective evaluations have been collected from 20 small-/medium-sized halls in Denmark used for amplified rhythmic music concerts (pop, rock, jazz). The purpose of the study was to obtain knowledge about optimum acoustic conditions for this type of hall. The study is motivated by the fact that most concert tickets sold in Denmark relate to concerts within these genres in this kind of venue. The subjective evaluations were carried out by professional musicians and sound engineers who responded on the basis of their experiences working in these (and other) halls. From the relationships between the subjective evaluations and the objective data, recommended values for reverberation time across frequency are suggested. For halls with volume between 50.000 ft3 and 160.000 ft3, the optimal range is 0.7 s to 1.0 s without audience (and chairs). T30 should be frequency independent, so that clarity remains high also at the lower frequencies. A lower limit for T30 was identified. The paper also proposes possible hall designs that seek to fulfill the demands of sound engineers and musicians, as found in the investigation.
Compliance with city noise regulations by small venue restaurants, lounges, and sports bars
Authors: Hale Marlund E.
Published: September 2008

There are many small venues that offer recorded and/or live musical entertainment to their regular customers as well as to attract new customers to their establishments. Many municipalities have enacted noise regulations requiring that such commercial entertainment meet exterior community noise limits and sometimes even indoor noise standards. This paper presents field performance test results for several small businesses that failed to meet the regulatory noise limits and were in jeopardy of being fined or closed down until they could comply with the regulatory noise requirements. The businesses all provided musical entertainment, and were located on busy streets in commercial buildings. All of the businesses also had a customer base that expected loud music. Most of the businesses were afraid that reducing the volume of their musical entertainment would cause them to lose customers and money. Several solutions were explored and recommendations made that satisfied both sides of the issue.
Frequency-swept directivity lobes—An emerging functional principle of biosonar beamforming
Authors: Müller Rolf , Lu Hongwang , Zhang Zhiwei , Buck John R.
Published: September 2008

In all bat species, the spatial sensitivity of the biosonar system is mainly determined by the shape of the outer ears. In addition, a noseleaf surrounds the nostrils in many species and shapes the spatial distribution of the emitted sound energy. Predicting the beam-forming effects of these structures numerically from their surface geometry has enabled comparative studies of high-resolution beam pattern estimates across a large set of different bat species. The beam patterns obtained so far differ from common manmade transducers, such as loudspeakers and microphones. Strong asymmetric side lobes, which change direction as a function of frequency, are a distinguishing feature consistently seen in emission and reception beam patterns of the bats. Where investigated, the occurrence of these side lobes appears to be tied to the presence of flap-like structures (including the tragus of the pinna), which may be hypothesized to have evolved for this purpose. The presence of these side lobes suggests that bat biosonar has not been evolved to maximize the ensonification energy and sensitivity for a single small target unconditionally. Instead, the function of these strong side lobes could be explained as maximizing the information obtained in analogy to squinted beams used in manmade systems.
Possible vocalizations of the ivory-billed woodpecker (Campephilus principalis)
Authors: Collins Michael D. , Martin Richard S. , Dacol Dalcio K.
Published: September 2008

The Ivory-billed Woodpecker (Campephilus principalis) was feared to be extinct for decades, but there have been sightings in several states during the past few years. During a study at the last known nest sites in the 1930s, the characteristic kent calls of this species were recorded and other calls were observed but not recorded. There have been recent observations and recordings of high-pitched calls that are suspected to be ivorybill vocalizations. In the Pearl River, the calls were heard mixed in with kents during an encounter with two ivorybills. At the same site two days later, the calls were heard and recorded after an ivorybill was flushed, and the movements of the source of the calls was correlated with the movements of the ivorybill (video was also obtained during the encounter). Similar calls were recorded along with kent-like calls in the Choctawhatchee River at a site where there were sightings the same day and the previous day. The calls were also heard in the Congaree Swamp after a recording of kents was played back. The calls are similar to one of the calls of the Blue Jay (Cyanocitta cristata), but this conspicuous species was not observed during the encounters.
Buzz digging and buzz plastering in the black-and-yellow mud dauber wasp, Sceliphron caementarium (Drury)
Authors: Fink Tom , Ramalingam Vijay , Seiner John , Skals Niels , Streett Douglas
Published: September 2008

The black-and-yellow mud dauber digs mud with its mandibles at pond or puddle edges, flies with a mud ball to a locality that is dark and protected from rain, and then immediately begins to form a mud tube for eventual provisioning with paralyzed spiders as food for its single developing larva (only one egg is depositied per tube). Digging and plastering (making a mud tube) are always accompanied by intense vibrations (intense enough to shake one’s hand when holding the wasp with forceps) caused by the wing muscles. Visual and acoustic details of digging and plastering were studied by high speed video (usually 2,000 fps) correlated with acoustical data recorded with laser Doppler vibrometry, microphones, and accelerometers. High definition video was also used to view the general process of digging and plastering, but it is impossible to visualize the vibrations except with high-speed video. The vibration of the wing muscles causes the head to vibrate at the same frequency, which mechanically aids digging and plastering. Pulling and pushing mud with the mandibles while digging are at different frequencies, and plastering is at an even lower frequency. The wasp can modulate the amplitude of these vibrations while digging or plastering.
The origin of storm wave noise and its application to passive acoustic remote sensing of bubbles
Authors: Deane Grant , Czerski Helen
Published: September 2008

Breaking waves in storms create large numbers of bubbles at the ocean surface. Direct measurement of the bubbles is difficult, and there are few data on the numbers, sizes, and creation rates of the large, transient bubbles formed in whitecaps. These bubbles could be measured using passive acoustic remote sensing if the excitation mechanism of sound production from newly created bubbles was understood. Using bubbles released from a nozzle as a model system, we have determined that sound production is driven by the collapse of an air neck formed immediately after bubble pinch-off. Laboratory experiments and model calculations of the mechanism will be presented. [Work supported by ONR and NSF.]
Acoustic surface-interaction phenomena during storms: A semi-empirical approach
Authors: Gauss Roger , Fialkowski Joseph
Published: September 2008

When storms arise at sea, winds transfer energy to the water surface, raising waves that grow higher and longer, and generating subsurface bubbles via breaking waves. This increased complexity of the undersea air-sea boundary-interaction zone makes it important to be able to isolate and characterize the contributions of the rough air-sea interface, bubbles, and fish on an impinging acoustic field to allow realistic assessments of their impact on sonar system performance. Active transmissions can be used to remotely sense this environment and help decipher the interaction process. In this paper, a coupled approach is presented that provides self-consistent oceanographic and acoustic models. Through a combination of oceanographic and acoustic measurements and modeling, semi-empirical oceanographic models of key phenomena (wave age, air-void fraction) are first developed that depend on readily-observable environmental parameters (wind speed and significant wave height). In turn, these models are used to develop broadband semi-empirical acoustic scattering and loss models that environmentally depend on these same parameters. The paper concludes with illustrations of how strong this dependence is during storm conditions, as well as the extent to which other scattering phenomena (fish) can be masked. [Work supported by ONR.]
Quantifying the destructive power of hurricanes with naturally occurring undersea sound
Authors: Makris Nicholas C. , Wilson Joshua D.
Published: September 2008

A passive ocean-acoustic method for quantifying the destructive power of a hurricane with accuracy similar to that of in situ aircraft measurements is presented. The method has been demonstrated by comparing underwater acoustic data with aircraft wind speed data. Both the acoustic and wind speed data were obtained in 1999, when hurricane Gert passed over an autonomous underwater hydrophone in the North Atlantic. The implications of this relatively safe and inexpensive ocean acoustic method for hurricane classification and disaster planning are discussed. A new experimental initiative between Mexico and the United States on ocean acoustic hurricane quantification will be described. [This work is supported by the Office of Naval Research and Seagrant.]
Comparison of wind driven ambient noise in shallow and deep-water ocean environments
Authors: Knobles David , Cho Steven E. , Joshi Sumedh M. , Gaul Roy , Sperry Brian J.
Published: September 2008

Measured sound pressure time series in shallow and deep-water ocean environments are used to investigate the character of wind-generated noise over a range of wind speed of 2–40 knots and a frequency band of 10–3,000 Hz. In 2006, acoustic data were collected during tropical storm Ernesto off the New Jersey continental shelf in shallow (70 m) water. Ambient noise from these data is compared to deep-water measurements at several locations in the Northwest and the Northeast Pacific. The results also are compared to previously reported measurements by [Kuperman and Ferla (1985)], [Wenz (1962)], and others. The analysis includes a technique for separating background shipping noise from the wind-induced component of ambient noise. The system electronic noise floor and other extraneous sources of noise are evaluated to assure that the ambient noise measurements are not corrupted. Physical mechanisms examined include a wind-saturation effect that limits the ability to acoustically monitor distant storms and the effect of shallow water propagation on the character of wind noise. The identification of the distant shipping part of the spectrum allows for inferences to be made on the low frequency part of the ambient noise spectrum. [Work supported by ONR.]