bluuebunny/crossref_metadata_2025 huggingface dataset:
EXPERIMENTAL INVESTIGATION OF DRYING KINETICS OF CHERRY LAUREL
Authors: KAYA AHMET , AYDIN ORHAN
Published: March 2008

The present study was aimed at experimentally and theoretically investigating the drying kinetics of cherry laurel fruit (Laurocerasus officinalis Roemer) in a convective dryer. In the experimental part, effects of various values of drying air parameters, including temperature and relative humidity, on the drying characteristics of cherry laurel fruit were determined. Sorption isotherms of the dried cherry laurel fruit were also determined for different values of the temperature and the equilibrium relative humidity of the drying air. In the theoretical part, different thin‐layer drying models, such as Henderson and Papis, Newton and two‐term exponential models, have been used to analyze the moisture variation of cherry laurel. The two‐term exponential model was found to be the most suitable for describing the drying curves of cherry laurel fruit. A diffusion model was used to describe the moisture diffusivity at each temperature and relative humidity. The moisture diffusivity of cherry laurel varied between 1.896 and 3.252 × 10−10 m2/s. The temperature dependence of the diffusivity coefficient was also described by the Arrhenius‐type relationship. The activation energy of cherry laurel has been found as 15.806 kJ/mol.

PRACTICAL APPLICATIONS

Drying is used in order to preserve and store fruits for longer periods by removing some of their moisture content. In addition, commercial interest on dried fruits has been increasing. Improper drying causes considerable damage and waste of seasonal fruits in many countries. In the present study, some practical information about the drying kinetics of cherry laurel during convective drying is presented, which will be necessary for a food design engineer in the design and optimization of the drying system.
Computational Approaches to the Study of Language Change
Authors: Baker Adam
Published: March 2008

The article reviews computational studies of language change. Computer models of change are helpful because of the complexity of the behavior involved: an entire population of complex, interacting agents must be accounted for. Computational studies frequently bring to light hidden implications of theories, which make them relevant to the theoretical development of both acquisition and change. Studies of language change have focused on discovering mathematical properties of dynamical systems, or on simulating populations of speakers that interact with one another and change their internal states as a result. Models of lexical (including phonological) and syntactic change are considered. Computational models of change have proved useful tools for testing theories of language change, and will prove more useful as the field matures to include more systematic studies of the effects of varying model parameters in complex simulations.
Linguistic Research and Language Teaching
Authors: Tsujimura Natsuko
Published: March 2008

It is not uncommon for theoretical linguists to find themselves involved in language teaching because of their expertise in a specific language, even though their primary training is not in language instruction. Apparent lack of intellectual stimulus and career development is a typical concern shared by those who are in these academic positions; and it is sometimes the case that time spent on language teaching is perceived to be detrimental to a successful tenure decision. Based on my own experience as a linguist in a language department for the past 20 years, I will discuss some of these dilemmas and suggestions that may lead to a more positive outlook of those who face a similar situation.
Commodity Chains, Rural Development and the Global Agri‐food System
Authors: Challies Edward R. T.
Published: March 2008

Taking as its starting point the enduring ‘agrarian question’, or crisis, of uneven rural development, the paper traces the evolution of the global commodity chain approach as a means for conceptualising the complexities and contradictions of the global agri‐food system. Of central concern is the potential that commodity chain analysis has for illuminating the dynamics of local development. Much useful critique and debate (reflecting debate within human geography more generally) has highlighted theoretical and methodological shortcomings within commodity chain analysis, and critique and subsequent innovations have potentially strengthened the utility of the commodity chain approach. However, it is argued that if commodity chain studies are to effectively grasp the complexities of contemporary agri‐food globalisation, and its challenges for local social and economic development, they must maintain a global production‐consumption gaze, while not losing sight of local productive relations and rural livelihoods at the roots of the chains. In order to be inclusive of small‐scale primary producers, it is argued, commodity chain analyses might usefully incorporate aspects of rural livelihoods approaches.
Chloroquine is effective against influenza A virus in vitro but not in vivo
Authors: Vigerust David J. , McCullers Jonathan A.
Published: March 2008

Background  Chloroquine is an inexpensive and widely available 9‐aminoquinolone used in the management of malaria. Recently, in vitro assays suggest that chloroquine may have utility in the treatment of several viral infections including influenza.

Objectives  We sought to test whether chloroquine is effective against influenza in vivo in relevant animal models.

Methods  The effectiveness of chloroquine at preventing or ameliorating influenza following viral challenge was assessed in established mouse and ferret disease models.

Results  Although active against influenza viruses in vitro, chloroquine did not prevent the weight loss associated with influenza virus infection in mice after challenge with viruses expressing an H1 or H3 hemagglutinin protein. Similarly, clinical signs and viral replication in the nose of ferrets were not altered by treatment.

Conclusions  Although in vitro results were promising, chloroquine was not effective as preventive therapy in vivo in standard mouse and ferret models of influenza virus infection. This dampens enthusiasm for the potential utility of the drug for humans with influenza.
Cross‐neutralisation of antibodies elicited by an inactivated split‐virion influenza A/Vietnam/1194/2004 (H5N1) vaccine in healthy adults against H5N1 clade 2 strains
Authors: Höschler Katja , Gopal Robin , Andrews Nick , Saville Melanie , Pepin Stephanie , Wood John , Zambon Maria C.
Published: March 2008

Background  Highly pathogenic avian influenza A H5N1 viruses are widespread in different parts of the world and have evolved into clade 1 and 2 lineages. Their continuing circulation represents serious pandemic threat, spurring human vaccine development efforts. Initial clinical trials tested vaccines prepared from clade 1 strains circulating in 2004.

Methods  Post‐vaccination sera from a phase I trial of an inactivated split‐virion vaccine based on A/Vietnam/1194/2004/NIBRG14 (H5N1) were analysed in vitro for cross‐reactivity against highly pathogenic, wild‐type clade 2 H5N1 strains isolated from human cases, and their corresponding reverse genetics derived vaccine candidate strains.

Results  Neutralisation of clade 1 and 2 wild‐type and reverse‐genetics viruses was seen, with highest titres observed for viruses most closely related to the vaccine strain. There was no consistent relationship between vaccine dose given, or presence of aluminium adjuvant and cross‐neutralising antibody titre, possibly because of small sample size. Use of wild‐type highly pathogenic strains compared with antigenically equivalent reverse‐genetics viruses suggests presence of a higher level of cross‐neutralising antibody.

Conclusion  Vaccination with a clade 1 H5N1 virus elicited antibodies capable of neutralising diverse clade 2 H5N1 strains. This data underlines that while a close match between vaccine virus and circulating virus is important to achieve maximum protection, population priming with a ‘pre‐pandemic’ vaccine may be beneficial for the protection of a naïve population. The data suggests that use of reverse‐genetic viruses in neutralisation assays may underestimate the extent of cross‐protective antibody present following H5N1 vaccination.
Chest CT findings of influenza virus‐associated pneumonia in 12 adult patients
Authors: Fujita Jiro , Bandoh Shuji , Yamaguchi Masahiro , Higa Futoshi , Tateyama Masao
Published: March 2008

Objective  In this study, we describe the chest computed tomography findings of influenza virus‐associated pneumonia in adult patients.

Methods  Our retrospective study included 12 adult patients who had proven influenza virus ‐ associated pneumonia.

Results  Out of 12 patients, six were diagnosed as having pure influenza virus pneumonia, five as having bronchopneumonia caused by bacteria associated with influenza A infection, and one as having a cryptogenic organizing pneumonia associated with influenza A infection.

Conclusion  Radiographic findings of influenza virus pneumonia in adult patients consist of ground‐glass attenuation. Localized patchy consolidations were observed in cases of bronchopneumonia.
Influenza vaccination coverage rates in Europe – covering five consecutive seasons (2001–2006) in five countries
Authors: Holm Majbrit V. , Blank Patricia R. , Szucs Thomas D.
Published: March 2008

Objective  To understand potential drivers and barriers to influenza vaccination in the general population.

Methods  47 982 household surveys were conducted in five European countries between 2001 and 2006.

Results  Overall influenza vaccination coverage increased over the years and reached 26·2% in 2005/06. Among the elderly ≥65 years, the rate increased significantly to 67·8% (2005/06). The most common reason for being vaccinated over the 5 years was the perception of influenza as a serious illness, which people want to avoid. The main reason for not getting vaccinated among those never previously vaccinated was feeling that they were unlikely to catch influenza. A recommendation by the family physician was the most encouraging factor for vaccination.
Primary glaucoma in Burmese cats
Authors: HAMPSON ECGM , SMITH RIE , BERNAYS ME
Published: March 2008

Objective To document the clinical signs and management of primary glaucoma in Burmese cats.

Design A retrospective study of six affected Burmese cats, from 1996 to 2001.

ProcedureSix Burmese cats diagnosed with primary glaucoma were managed over periods varying from 3 months to 4.5 years. Clinical details were obtained from practice records. Gonioscopic examination of the drainage or iridocorneal angle in eyes of these affected cats was made.

ResultsSix desexed female Burmese cats (ages 7.0 to 10.5 years) presented with complaints of either unilateral (n = 4) or bilateral (n = 2) red eye, dilated pupil or enlarged eye. In one of the affected cats, one eye had been enucleated prior to the commencement of the study, thus a total of 11 eyes were examined. Clinically, all affected eyes (n = 8) had injected episcleral blood vessels and elevated intraocular pressure. Gonioscopy revealed the presence of nine narrow and two closed irido‐corneal angles. Medical therapy included topical 2% dorzolamide (n = 8), 0.5% timolol maleate (n = 1), 0.005% latanoprost (n = 1) and 0.5–1.0% prednisolone acetate (n = 8). Surgery was performed in six eyes using either diode laser (n = 5) and/or cryothermy (n = 2) and one eye was eviscerated, with implantation of a prosthesis. With therapy, five affected eyes maintained vision and normal intraocular pressure, one eye remained blind with normal intraocular pressure, one eye remained blind with elevated intraocular pressure and one eye was eviscerated.

Conclusions The Burmese cat may be predisposed to primary narrow‐angle glaucoma. Early diagnosis and continuous antiglaucoma therapy can help control intraocular pressure and maintain vision.
Arthroscopic management of septic polyarthritis in a dog
Authors: FEARNSIDE SM , PRESTON CA
Published: March 2008

A 4½‐month‐old male Neapolitan Mastiff was presented with a history of severe non weight‐bearing lameness, depression and anorexia, following 6 weeks of intermittent thoracic limb lameness that had deteriorated in the previous 72 hours. Haematogenous septic polyarthritis involving the right elbow joint and left glenohumeral joint was diagnosed, with blood and joint cultures revealing a Pasteurella species. Arthroscopy was utilised to facilitate joint evaluation and effect drainage of both joints. Clinical remission was achieved within 48 hours. Arthroscopy provided a minimally invasive yet thorough joint examination, lavage, and drainage of fibrinopuru‐lent debris, thereby allowing early postoperative mobility and minimal morbidity.
Catheters: a review of the selection, utilisation and complications of catheters for peripheral venous access
Authors: TAN RHH , DART AJ , DOWLING BA
Published: March 2008

Intravenous catheters are used for the administration of medications and fluids and are an integral part of veterinary practice. The aim of catheter use is to optimise administration of medication and minimise complications such as thrombus formation, thrombophlebitis and sepsis. Catheters made from teflon are less flexible, less durable and stimulate more tissue reaction than polyurethane or silicon. However silicon catheters are more expensive and complicated to insert. Generally, for veterinary practice, the biostability and cost of polyurethane catheters make them preferable for short and long‐term use. The smallest diameter catheter should be selected to minimise internal vessel wall contact and irritation without compromising medication delivery. The site of insertion varies with individual preference, vessel access and patient compliance. The jugular, cephalic, saphenous, ear, lateral thoracic and subcutaneous abdominal veins are accessible. Hair removal and a thorough aseptic skin preparation should be performed prior to catheter insertion. Daily maintenance is required to detect complications and maximise catheter longevity. Potential complications include thrombus formation, thromboembolism, bacterial colonisation and septicaemia, blood loss and air embolism. Permanent or transient skin dwelling bacteria are commonly isolated if sepsis occurs. The development of novel antiseptic and antibiotic impregnated catheters may reduce the complications associated with catheter infection in the future.
Serological evidence of exposure to tick fever organisms in young cattle on Queensland dairy farms
Authors: SSERUGGA JN , JONSSON NN , BOCK RE , MORE SJ
Published: March 2008

Objectives To compare the features of farms on which the exposure of young cattle to tick fever organisms is sufficient to ensure that immunity is high and the risk of clinical disease is low (endemic stability) with those of farms on which exposure is insufficient to induce widespread immunity (hence without endemic stability); to examine the relationships between the management of ticks and tick fever, and endemic stability to Babesia bovis, B bigemina and Anaplasma marginale.

Design Cross‐sectional study of 874 cattle between the ages of 6 and 15 months on 64 dairy farms, from three centres in south‐eastern Queensland (Mutdapilly, Dayboro and Kenilworth) and one centre in far‐north Queensland (Malanda).

Procedure Blood samples collected from between 5 and 20 calves from each farm were submitted for serological assay to determine exposure to B bovis, B bigeminaand A marginale. A questionnaire about the farm characteristics and the management of ticks and tick fever was completed with each farmer.

Results On 73% of farms, confirmed clinical cases of tick fever were recalled by the farmer, indicating that tick fever was a threat on most farms. The majority of herds in the study (54 of 64) did not have sufficient numbers of seropositive animals aged between 6 and 15 months to have a low risk of tick fever. Region had an effect on the likelihood of endemic stability for all tick fever organisms. Cattle near Malanda in Far‐north Queensland were more likely to be seropositive to B bovisand B bigemina. The method, strategy and intensity of tick control were not related to the likelihood of endemic stability when the effect of region was considered. The decision to leave a few ticks on cattle in an effort to induce endemic stability did increase the likelihood of endemic stability to A marginale. However, in practical terms, it was ineffective, because only 26% of these farms had endemic stability against all three organisms.

Conclusions Given the low proportion of farms that have endemic stability to the tick fever organisms and the high likelihood of clinical disease, vaccination is recommended to protect dairy cattle from tick fever throughout the tick infested area of Queensland. However, further work is required to determine the economic value of vaccination, taking into account the costs of vaccination, of outbreaks and the protective value of vaccination.
Type 1B external fixation of a metacarpal fracture in an alpaca
Authors: STAUDTE KL , GIBSON NR
Published: March 2008

External skeletal fixation can be used in small ruminants as a successful, economic, alternative to internal fixation. In this case report, a type 1B frame was used on an alpaca to salvage a comminuted metacarpal fracture after failed internal fixation. Positioning the frame on the caudal aspect of the limb allowed full carpal flexion for kneeling and hence normal use of the limb throughout the recovery period. Complete healing occurred without further complications.
Management of obstructive urolithiasis and concurrent urethral rupture in a goat
Authors: PEARCE SG , DEARO AC , HOWARD BE , BRISSON BA
Published: March 2008

A 4‐month‐old, male castrated Alpine White goat presented to the University of Guelph, Veterinary Teaching Hospital, with urolithiasis and a ruptured urethra. A tube cystostomy was performed using an indwelling Foley catheter. Postoperatively, the goat remained in good health, and was discharged with the cystostomy catheter in situ. Five weeks following surgery, the goat was noted to pass urine through its urethra. Seven weeks following surgery, the catheter became dislodged and the goat was observed to urinate normally. Six months following surgery, the goat was apparently healthy and urinating normally. Tube cystostomy may be a useful therapeutic option in the management of small ruminants with obstructive urolithiasis with concurrent rupture of the urethra, especially for cases in which treatment cost is a limiting factor.
NURSE STRESS IN HOSPITAL AND SATELLITE HAEMODIALYSIS UNITS
Authors: Dermody Kirsten , Bennett Paul N.
Published: March 2008

Aim: To explore nurse stress in both in‐centre hospital haemodialysis and satellite haemodialysis unit in an Australian city's health service.

Method: Focus groups from both in‐centre and satellite dialysis units were undertaken followed by questionnaires generated by the focus group data.

Results: In‐centre nursing staff rated the busyness of the unit as the maximum stress and stated that they felt this high level of stress on a daily basis. The most notable stressor for the staff at the satellite unit related to patient behaviour and the perceived unrealistic expectations of the patient followed by patients arriving unwell at the unit.

Conclusion: Nurses suffer stress on a daily basis in both in‐centre and satellite dialysis units. The major stressors differ from in‐centre to satellite dialysis units.
Synergistic premalignant effects of chronic ethanol exposure and insulin receptor substrate‐1 overexpression in liver
Authors: Longato Lisa , De La Monte Suzanne , Califano Sophia , Wands Jack R.
Published: March 2008

Aim:  Insulin receptor substrate, type 1 (IRS‐1) transmits growth and survival signals, and is overexpressed in more than 90% of hepatocellular carcinomas (HCCs). However, experimental overexpression of IRS‐1 in the liver was found not to be sufficient to cause HCC. Since chronic alcohol abuse is a risk factor for HCC, we evaluated potential interactions between IRS‐1 overexpression and chronic ethanol exposure by assessing premalignant alterations in gene expression.

Methods:  Wild‐type (wt) or IRS‐1 transgenic (Tg) mice, constitutively overexpressing the human (h) transgene in the liver, were pair‐fed isocaloric liquid diets containing 0% or 24% ethanol for 8 weeks. The livers were used for histopathologic study and gene expression analysis, focusing on insulin, insulin‐like growth factor (IGF) and wingless (WNT)–Frizzled (FZD) pathways, given their known roles in HCC.

Results:  In wt mice, chronic ethanol exposure caused hepatocellular microsteatosis with focal chronic inflammation, reduced expression of proliferating cell nuclear antigen (PCNA) and increased expression of IGF‐I and IGF‐I receptor. In hIRS‐1 Tg mice, chronic ethanol exposure caused hepatic micro‐ and macrosteatosis, focal chronic inflammation, apoptosis and disordered lobular architecture. These effects of ethanol in hIRS‐1 Tg mice were associated with significantly increased expression of IGF‐II, insulin, IRS‐4, aspartyl–asparaginyl β hydroxylase (AAH), WNT‐1 and FZD 7, as occurs in HCC.

Conclusion:  In otherwise normal liver, chronic ethanol exposure mainly causes liver injury and inflammation with impaired DNA synthesis. In contrast, in the context of hIRS‐1 overexpression, chronic ethanol exposure may serve as a cofactor in the pathogenesis of HCC by promoting expression of growth factors, receptors and signaling molecules known to be associated with hepatocellular transformation.
Formulation of A State Equation Including Fractional-Order State Vectors
Authors: Kuroda Masaharu
Published: March 2008

In recent years, applications of fractional calculus have flourished in various science and engineering fields. Particularly in engineering, control engineering appears to be expanding aggressively in their applications. Exemplary are the CRONE controller and the PIλDμ controller, which is categorizable into applications of fractional calculus in classical control theory. A state equation can be called as the foundation of modern control theory. However, the relationship between fractional derivatives and the state equation has not been examined sufficiently. Consequently, a systematic procedure referred to every researcher on the fractional-calculus side or control-theory side has not yet been established. For this study, therefore, involvement of fractional-order derivatives into a state equation is demonstrated here for ready comprehension by researchers. First, the procedures are explained generally; then the technique to incorporate a fractional-order state vector into a conventional state equation is given as an example of the applications. The state-space representation in this study is useful not only to model a controlled system with fractional dynamics but also for design and implementation of a controller to control fractional-order states. After introducing the basic parts, the benefits of modern control theory including robust control theories, such as H∞ and μ-analysis and synthesis in their integrities, can be applied to this fractional-order state equation.
Dynamics of a Duffing Oscillator With Two Time Delays in Feedback Control Under Narrow-Band Random Excitation
Authors: Jin Yanfei , Hu Haiyan
Published: March 2008

The paper presents analytical and numerical results of the primary resonance of a Duffing oscillator with two distinct time delays in the linear feedback control under narrow-band random excitation. Using the method of multiple scales, the first-order and the second-order steady-state moments of the primary resonance are derived. For the case of two distinct time delays, the appropriate choices of the combinations of the feedback gains and the difference between two time delays are discussed from the viewpoint of vibration control and stability. The analytical results are in well agreement with the numerical results.
Nonlinear Analysis of Road Traffic Flows in Discrete Dynamical System
Authors: Xu Meng , Gao Ziyou
Published: March 2008

In this paper, we investigate the dynamic behavior of road traffic flows and study if chaotic phenomena exist in a traffic flow dynamic system. Two discrete dynamic models are proposed, which are derived from Del Castillo and Benitez’s exponential curve model and maximum sensitivity curve model. Both models have two parameters, which are the ratio of free flow and spacing average speed and the ratio of the absolute value of kinematic wave speed at jam density and the free flow speed. Chaos is found in the two models when the two values increase separately. The Lyapunov exponents and fractal dimension were used to examine the characters of the chaos in the two models.
Finite-Time Controllability of Fractional-Order Systems
Authors: Adams Jay L. , Hartley Tom T.
Published: March 2008

In this paper, the conditions that lead to a system output remaining at zero with zero input are considered. It is shown that the initialization of fractional-order integrators plays a key role in determining whether the integrator output will remain at a zero with zero input. Three examples are given that demonstrate the importance of initialization for integrators of order less than unity, inclusive. Two examples give a concrete illustration of the role that initialization plays in keeping the output of a fractional-order integrator at zero once it has been driven to zero. The implications of these results are considered, with special consideration given to the formulation of the fractional-order optimal control problem.
On the Differential Geometry of Flows in Nonlinear Dynamical Systems
Authors: Luo Albert C. J.
Published: March 2008

In order to investigate the geometrical relation between two flows in two dynamical systems, a flow for an investigated dynamical system is called the compared flow and a flow for a given dynamical system is called the reference flow. A surface on which the reference flow lies is termed the reference surface. The time-change rate of the normal distance between the reference and compared flows in the normal direction of the reference surface is measured by a new function (i.e., G function). Based on the surface of the reference flow, the kth-order G functions are introduced for the noncontact and lth-order contact flows in two different dynamical systems. Through the new functions, the geometric relations between two flows in two dynamical systems are investigated without contact between the reference and compared flows. The dynamics for the compared flow with a contact to the reference surface is briefly addressed. Finally, the brief discussion of applications is given.
Squaring the Circle: A Mathematically Rigorous Physics First
Authors: Goodman Robert , Etkina Eugenia
Published: March 2008

For more than a hundred years there has been a debate about the sequence in which high school science should be taught. Many advocates of “Physics First” support a more conceptual ninth-grade physics course followed by chemistry and then biology while supporters of mathematically rigorous physics favor a sequence of biology-chemistry-physics. This paper describes a new approach that incorporates some of the best arguments from both sides. The main idea is to teach a mathematically rigorous ninth-grade physics course based on algebra alone, avoiding trigonometry.1,2 By selecting topics from the AP Physics B curriculum that form a foundation for both chemistry and biology, one can establish an efficient science sequence. The goal of this paper is to describe this new approach to Physics First and present data supporting its effectiveness.
Finding the Center of Volume of the Forearm
Authors: Klein Stacy S. , Roselli Robert J.
Published: March 2008

A typical first-year physics course teaches students about the center of mass using both regular and irregularly shaped objects. Students often suspend an object in each of two dimensions from a string with the intersection determining the center of mass of the object. While these methods can be effective, they are not particularly exciting or motivating. Wouldn't it be more interesting to find the center of mass of a body part, such as the forearm? Through a series of simple measurements and assumptions, students can generate a first-order approximation of the center of volume and center of mass of their forearm. Comparisons can be made between the muscular forearm of the football player in the class with the scrawniest arm in the room, creating a deeper understanding of center of mass and how it relates to the human body.
Critical Thinking: Error Sources and Energy in a Conservation of Momentum Lab
Authors: Rosen Robert D.
Published: March 2008

Our school has a very small budget for equipment. So finding a gem like a conservation of momentum lab requiring only basic materials (TPT, October 2005)1 adds a great deal to my physics course. In this lab, a “shooter” nickel makes a non-head-on collision with a stationary “target” nickel. Students measure the distance each nickel slides after the collision and the angles shown in the diagram. The paper by James Hunt1 explains how these data can be used to verify conservation of momentum in the direction perpendicular to the shooter's initial velocity. This paper suggests some possible sources of error and explains how the angles can be used to study energy relationships in the collision.
A $400 Photogate for $50 or Less
Authors: Horton Michael
Published: March 2008

Photogates are extremely valuable in introductory physics, but the price can be prohibitive for the average high school teacher. I have designed several photogates that one can construct for less than $50 with just a little soldering skill. The photogate featured here sells for nearly $400 in science catalogs and you can build it for around $50 depending on the case that you use.
Join a Physics Teaching Community
Authors: Jones David
Published: March 2008

David Jones is the Educational Outreach Coordinator of CHEPREO at Florida International University. David is a member of “Fizmo,” a local community of high school teachers in Miami-Dade County in Florida. Fizmo is sponsored by CHEPREO and PhysTEC. CHEPREO is an NSF-sponsored grant that joins high-energy physics research, physics teaching reform, and educational outreach centered at Florida International University. Information on CHEPREO can be found at http://www.chepreo.org.
Inverted direction of wave propagation (IDWP) in the cochlea
Authors: de Boer Egbert , Zheng Jiefu , Porsov Edward , Nuttall Alfred L.
Published: March 2008

The “classical” view on wave propagation is that propagating waves are possible in both directions along the length of the basilar membrane and that they have identical properties. Results of several recently executed experiments [T. Ren, Nat. Neurosci. 2, 333–334 (2004) and W. X. He, A. L. Nuttall, and T. Ren, Hear. Res., 228, 112–122 (2007)] appear to contradict this view. In the current work measurements were made of the velocity of the guinea-pig basilar membrane (BM). Distortion products (DPs) were produced by presenting two primary tones, with frequencies below the characteristic frequency f0 of the BM location at which the BM measurements were made, with a constant frequency ratio. In each experiment the phase of the principal DP, with frequency 2f1−f2, was recorded as a function of the DP frequency. The results indicate that the DP wave going from the two-tone interaction region toward the stapes is not everywhere traveling in the reverse direction, but also in the forward direction. The extent of the region in which the forward wave occurs appears larger than is accounted for by classical theory. This property has been termed “inverted direction of wave propagation.” The results of this study confirm the wave propagation findings of other authors. The experimental data are compared to theoretical predictions for a classical three-dimensional model of the cochlea that is based on noise-response data of the same animal. Possible physical mechanisms underlying the findings are discussed.
Classification of broadband echoes from prey of a foraging Blainville’s beaked whale
Authors: Jones Benjamin A. , Stanton Timothy K. , Lavery Andone C. , Johnson Mark P. , Madsen Peter T. , Tyack Peter L.
Published: March 2008

Blainville’s beaked whales (Mesoplodon densirostris) use broadband, ultrasonic echolocation signals with a −10dB bandwidth from 26to51kHz to search for, localize, and approach prey that generally consist of mid-water and deep-water fishes and squid. Although it is well known that the spectral characteristics of broadband echoes from marine organisms vary as a function of size, shape, orientation, and anatomical group, there is little evidence as to whether or not free-ranging toothed whales use spectral cues in discriminating between prey and nonprey. In order to study the prey-classification process, a stereo acoustic tag was deployed on a Blainville’s beaked whale so that emitted clicks and the corresponding echoes from targets in the water could be recorded. A comparison of echoes from targets apparently selected by the whale and those from a sample of scatterers that were not selected suggests that spectral features of the echoes, target strengths, or both may have been used by the whale to discriminate between echoes. Specifically, the whale appears to favor targets with one or more nulls in the echo spectra and to seek prey with higher target strengths at deeper depths.
Passive fathometer processing
Authors: Gerstoft Peter , Hodgkiss William S. , Siderius Martin , Huang Chen-Fen , Harrison Chris H.
Published: March 2008

Ocean acoustic noise can be processed efficiently to extract Green’s function information between two receivers. By using noise array-processing techniques, it has been demonstrated that a passive array can be used as a fathometer [Siderius, et al., J. Acoust. Soc. Am. 120, 1315–1323 (2006)]. Here, this approach is derived in both frequency and time domains and the output corresponds to the reflection sequence. From this reflection sequence, it is possible to extract seabed layering. In the ocean waveguide, most of the energy is horizontally propagating, whereas the bottom information is contained in the vertically propagating noise. Extracting the seabed information requires a dense array, since the resolution of the bottom layer is about half the array spacing. If velocity sensors are used instead of pressure sensors, the array spacing requirement can be relaxed and simulations show that just one vertical velocity sensor is sufficient.
Thermal boundary layer effects on the acoustical impedance of enclosures and consequences for acoustical sensing devices
Authors: Thompson Stephen C. , LoPresti Janice L.
Published: March 2008

Expressions are derived for the acoustical impedance of a rectangular enclosure and of a finite annular cylindrical enclosure. The derivation is valid throughout the frequency range in which all dimensions of the enclosure are much less than the wavelength. The results are valid throughout the range from adiabatic to isothermal conditions in the enclosure. The effect is equivalent to placing an additional, frequency-dependent complex impedance in parallel with the adiabatic compliance. As the thermal boundary layer grows to fill the cavity, the reactive part of the impedance varies smoothly from the adiabatic value to the isothermal value. In some microphones, this change in cavity stiffness is sufficient to modify the sensitivity. The resistive part of the additional cavity impedance varies as the inverse square root of frequency at high frequencies where the boundary layer has not grown to fill the enclosure. The thermal modification gives rise to a thermal noise whose spectral density varies asymptotically as l∕f3∕2 above the isothermal transition frequency.
Near field Rayleigh wave on soft porous layers
Authors: Geebelen N. , Boeckx L. , Vermeir G. , Lauriks W. , Allard J. F. , Dazel O.
Published: March 2008

Simulations performed for a typical semi-infinite reticulated plastic foam saturated by air show that, at distances less than three Rayleigh wavelengths from the area of mechanical excitation by a circular source, the normal frame velocity is close to the Rayleigh pole contribution. Simulated measurements show that a good order of magnitude estimate of the phase speed and damping can be obtained at small distances from the source. Simulations are also performed for layers of finite thickness, where the phase velocity and damping depend on frequency. They indicate that the normal frame velocity at small distances from the source is always close to the Rayleigh pole contribution and that a good order of magnitude estimate of the phase speed of the Rayleigh wave can be obtained at small distances from the source. Furthermore, simulations show that precise measurements of the damping of the Rayleigh wave need larger distances. Measurements performed on a layer of finite thickness confirm these trends.
Factors influencing intelligibility of ideal binary-masked speech: Implications for noise reduction
Authors: Li Ning , Loizou Philipos C.
Published: March 2008

The application of the ideal binary mask to an auditory mixture has been shown to yield substantial improvements in intelligibility. This mask is commonly applied to the time–frequency (T–F) representation of a mixture signal and eliminates portions of a signal below a signal-to-noise-ratio (SNR) threshold while allowing others to pass through intact. The factors influencing intelligibility of ideal binary-masked speech are not well understood and are examined in the present study. Specifically, the effects of the local SNR threshold, input SNR level, masker type, and errors introduced in estimating the ideal mask are examined. Consistent with previous studies, intelligibility of binary-masked stimuli is quite high even at −10dB SNR for all maskers tested. Performance was affected the most when the masker dominated T–F units were wrongly labeled as target-dominated T–F units. Performance plateaued near 100% correct for SNR thresholds ranging from −20to5dB. The existence of the plateau region suggests that it is the pattern of the ideal binary mask that matters the most rather than the local SNR of each T–F unit. This pattern directs the listener’s attention to where the target is and enables them to segregate speech effectively in multitalker environments.
Detection of combined changes in interaural time and intensity differences: Segregated mechanisms in cue type and in operating frequency range?
Authors: Furukawa Shigeto
Published: March 2008

Although physiological studies have revealed segregated binaural pathways, namely the medial and lateral superior olives, it is unclear whether the human auditory system has separate mechanisms for different cue types (interaural time and intensity differences; ITD and IID, respectively) and for operating frequency ranges. This study hypothesized “channels” for ITD and IID processing, and examined channel interaction at low and high frequencies based on the signal detection theory. The stimuli were a 125- or 500-Hz tone and a 4-kHz tone amplitude-modulated with a half-wave-rectified 125-Hz sinusoid, presented dichotically with various baseline ITDs and IIDs. The detectability indices, d′, for ITD and IID changes, imposed individually or simultaneously in the same direction, were derived from the results of a forced-choice task. The degree of channel interaction was estimated by comparing d′ for combined cues with those for individual cues. The estimated interaction showed little effect of baseline ITD or IID. The results generally exhibited nonzero interaction, indicating that the cue processes are not completely independent. The interaction was stronger for high frequencies than for low frequencies. The results can be interpreted as indicating the involvement of different binaural mechanisms for different frequency regions.
Role of attention in overshoot: Frequency certainty versus uncertainty
Authors: Scharf Bertram , Reeves Adam , Giovanetti Holly
Published: March 2008

Overshoot, the elevation in the threshold for a brief signal that comes on close to masker onset, was measured with signal frequency certain (same frequency on every trial) or uncertain (randomized over trials). In broadband noise, thresholds were higher 2ms after masker onset than 200ms later, by 9dB with frequency certainty, by 6–7dB with uncertainty. In narrowband noise centered on the signal frequency, thresholds at 2ms were not elevated with certainty, but were elevated 4–5dB with uncertainty. Thus, frequency uncertainty leads to less overshoot in broadband noise, to more overshoot in narrowband noise. Reduced overshoot in broadband noise may come about because the masker, given its many frequencies, disrupts focusing at onset as much under certainty as uncertainty. Once the initial disruption dissipates, threshold is lower with certainty so overshoot is greater. In contrast, a narrowband noise with frequencies only near the signal does not disrupt focusing when the signal frequency is known beforehand, so overshoot is absent. When frequency is uncertain, the narrowband noise serves to focus attention on the signal frequency; as this requires time, detection near noise onset is poorer than later on, so overshoot is present.
Reduction of turbulent boundary layer induced interior noise through active impedance control
Authors: Remington Paul J. , Curtis Alan R. D. , Coleman Ronald B. , Knight J. Scott
Published: March 2008

The use of a single actuator tuned to an optimum impedance to control the sound power radiated from a turbulent boundary layer (TBL) excited aircraft panel into the aircraft interior is examined. An approach to calculating the optimum impedance is defined and the limitations on the reduction in radiated power by a single actuator tuned to that impedance are examined. It is shown that there are too many degrees of freedom in the TBL and in the radiation modes of the panel to allow a single actuator to control the radiated power. However, if the panel modes are lightly damped and well separated in frequency, significant reductions are possible. The implementation of a controller that presents a desired impedance to a structure is demonstrated in a laboratory experiment, in which the structure is a mass. The performance of such a controller on an aircraft panel is shown to be effective, if the actuator impedance is similar to but not the same as the desired impedance, provided the panel resonances are well separated in frequency and lightly damped.
Interaction of microbubbles with high intensity pulsed ultrasound
Authors: Fong Siew Wan , Klaseboer Evert , Khoo Boo Cheong
Published: March 2008

High intensity pulsed ultrasound, interacting with microbubble contrast agents, is potentially useful for drug delivery, cancer treatment, and tissue ablation, among other applications. To establish the fundamental understanding on the interaction of a microbubble (in an infinite volume of water) with an ultrasound pressure field, a numerical study is performed using the boundary element method. The response of the bubble, in terms of its shape at different times, the maximum bubble radius obtained, the oscillation time, the jet velocity, and its translational movement, is studied. The effect of ultrasound intensity and initial bubble size is examined as well. One important outcome is the determination of the conditions under which a clear jet will be formed in a microbubble in its interaction with a specific sound wave. The high speed jet is crucial for the aforementioned intended applications.
Methods for automatically analyzing humpback song units
Authors: Rickwood Peter , Taylor Andrew
Published: March 2008

This paper presents mathematical techniques for automatically extracting and analyzing bioacoustic signals. Automatic techniques are described for isolation of target signals from background noise, extraction of features from target signals and unsupervised classification (clustering) of the target signals based on these features. The only user-provided inputs, other than raw sound, is an initial set of signal processing and control parameters. Of particular note is that the number of signal categories is determined automatically. The techniques, applied to hydrophone recordings of humpback whales (Megaptera novaeangliae), produce promising initial results, suggesting that they may be of use in automated analysis of not only humpbacks, but possibly also in other bioacoustic settings where automated analysis is desirable.
Variation in call pitch among killer whale ecotypes
Authors: Foote Andrew D. , Nystuen Jeffrey A.
Published: March 2008

Vocal structure can vary between populations due to variation in ecology-dependent selection pressures, such as masking by background noise and the presence of eavesdroppers. Signalers can overcome these obstacles to effective communication by avoiding frequencies that overlap with background noise or the audible range of eavesdroppers. In the Northeastern Pacific three “ecotypes” of killer whale coexist in sympatry, but differ from one another in their diet and habitat use. The minimum frequency (Fmin) and the frequency containing the peak energy between 0 and 10kHz (Fpeak) of a random sample of calls produced by a population of each ecotype was measured. The offshore ecotype produced calls with a significantly higher Fmin than the other ecotypes, which could be a strategy to avoid masking by low frequency chronic bandlimited wind noise found in the offshore environment. The resident ecotype produced calls with a significantly higher Fmin and Fpeak than the transient ecotype. This could be to reduce detection by their salmonid prey, which has a narrow band, low frequency auditory range.
An ecological acoustic recorder (EAR) for long-term monitoring of biological and anthropogenic sounds on coral reefs and other marine habitats
Authors: Lammers Marc O. , Brainard Russell E. , Au Whitlow W. L. , Mooney T. Aran , Wong Kevin B.
Published: March 2008

Keeping track of long-term biological trends in many marine habitats is a challenging task that is exacerbated when the habitats in question are in remote locations. Monitoring the ambient sound field may be a useful way of assessing biological activity because many behavioral processes are accompanied by sound production. This article reports the preliminary results of an effort to develop and use an Ecological Acoustic Recorder (EAR) to monitor biological activity on coral reefs and in surrounding waters for periods of 1 year or longer. The EAR is a microprocessor-based autonomous recorder that periodically samples the ambient sound field and also automatically detects sounds that meet specific criteria. The system was used to record the sound field of coral reefs and other marine habitats on Oahu, HI. Snapping shrimp produced the dominant acoustic energy on the reefs examined and exhibited clear diel acoustic trends. Other biological sounds recorded included those produced by fish and cetaceans, which also exhibited distinct temporal variability. Motor vessel activity could also be monitored effectively with the EAR. The results indicate that acoustic monitoring may be an effective means of tracking biological and anthropogenic activity at locations where continuous monitoring by traditional survey methods is impractical.
Dual mode tuning strategy of a slightly asymmetric ring
Authors: Gil Park Han , June Kang Yeon , Hyun Kim Seock
Published: March 2008

Clear beats with proper periods in the first and the second vibration modes are very important factors for the sound of the Korean bell. In this study, the Korean bell is expressed as a circular ring with multiple point masses and a dual mode tuning strategy for clear beat with proper period. For the dual mode tuning, a dual mode equivalent ring model is composed with two point masses, which satisfies the mode pair conditions of the first mode and second mode simultaneously. By adding a suitable amount of additional masses to the dual mode equivalent ring model at appropriate positions, a clear beat with proper period in both of the two important modes is generated. The position and amount of the additional masses are determined analytically. Analytical tuning results are compared and verified with those of the finite element analysis.