bluuebunny/crossref_metadata_2025 huggingface dataset:
A potato carboxypeptidase inhibitor gene provides pathogen resistance in transgenic rice
Authors: Quilis Jordi , Meynard Donaldo , Vila Laura , Avilés Francesc X. , Guiderdoni Emmanuel , San Segundo Blanca
Published: June 2007

A defensive role against insect attack has been traditionally attributed to plant protease inhibitors. Here, evidence is described of the potential of a plant protease inhibitor, the potato carboxypeptidase inhibitor (PCI), to provide resistance to fungal pathogens when expressed in rice as a heterologous protein. It is shown that rice plants constitutively expressing the pci gene exhibit resistance against the economically important pathogens Magnaporthe oryzae and Fusarium verticillioides. A M. oryzae carboxypeptidase was purified by affinity chromatography and further characterized by mass spectrometry. This fungal carboxypeptidase was found to be a novel carboxypeptidase B which was fully inhibited by PCI. Overall, the results indicate that PCI exerts its antifungal activity through the inhibition of this particular fungal carboxypeptidase B. Although pci confers protection against fungal pathogens in transgenic rice, a significant cost in insect resistance is observed. Thus, the weight gain of larvae of the specialist insect Chilo suppressalis (striped stem borer) and the polyphagous insect Spodoptera littoralis (Egyptian cotton worm) fed on pci rice is significantly larger than that of insects fed on wild‐type plants. Homology‐based modelling revealed structural similarities between the predicted structure of the M. oryzae carboxypeptidase B and the crystal structure of insect carboxypeptidases, indicating that PCI may function not only as an inhibitor of fungal carboxypeptidases, but also as an inhibitor of insect carboxypeptidases. The potential impact of the pci gene in terms of protection against fungal and insect diseases is discussed.
Mental health resources for older persons in the Western Pacific Region of the World Health Organization
Authors: DE MENDONÇA LIMA Carlos A. , LEIBING Annette , BUSCHFORT Rüdiger
Published: June 2007

Background:  The Western Pacific Region of the World Health Organization (WHO) contains 27% of the world population and 29% of the world population of elderly people: it is the oldest among the six WHO regions. The demographic transition (from high child mortality and low life expectancy to a low child mortality and high life expectancy) is happening at high speed and this proportion of the world's elderly population is expected to increase significantly in the coming years. Consequently, there is a high risk that the number of older persons with mental disorders will significantly increase. To better understand the organization of care for older persons, data is being collected to reduce the imbalance between ‘disease information’ and ‘resource information’—information that addresses older persons' needs in terms of mental health care. This article presents some results for this region.

Method:  Data were essentially collected from the World Health Report 2005. The data concerning NGOs was obtained at the websites of the World Psychiatric Association, the World Federation of Neurology, the International Association of Gerontology and Geriatrics and Alzheimer's Disease International (ADI).

Results:  Because the mental health problems of older adults is still not a public health priority, the careful examination of individual countries nevertheless reveals certain specificities, such as divergent life expectancy or different values regarding aging. The authors present some recommendations for the development of care for elderly persons with mental disorders in the region based on the general recommendations made by WHO in the World Health Report 2001 (WHR 2001) and by WHO and the World Psychiatric Association (WPA) in some consensus statements on Psychiatry of the Elderly.

Conclusion:  The Western Pacific WHO region has a high proportion of older persons in its population (11.2% of total population), with important differences between the countries in life expectancy at birth. Strong cultural forces and migration may affect the growing and aging processes. Local poverty, with all the consequences it may have for health, may also be an important factor negatively influencing quality of life and life expectancy at birth. Mental health for all ages should become a priority issue in the public agenda in the region. National governments should make efforts to promote mental health and provide care for elderly persons with mental disorders, depending on local resources and cultures. As mental disorders in old age can represent a severe limitation on quality of life for older persons and their families good care should be extended to all concerned. The challenge of finding solutions for better living conditions for older people with mental health problems lies in the hands of researchers, policy makers and the population. Funding and creativity are two factors necessary to find such solutions.
HIV Risk in Women: A Multifaceted Model1
Authors: Harlow Lisa L. , Quina Kathryn , Morokoff Patricia J. , Rose Jennifer S. , Grimley Diane M.
Published: June 2007

A comprehensive model was designed to predict risky, HIV‐related sex in women from a set of behavioral, interpersonal, and psychoattitudinal measures. Survey measures were administered to two university samples of 234 and 263 women. Three sets of dependent measures assessed Partner‐Related HIV Risk, Unprotected Vaginal Intercourse, and Anal Intercourse. There were three multifaceted sets of independent variables that involved 12 factors. The first set, behavioral risk, involved (a) Social Substance Use, (b) Hard Substance Use, (c) Foreplay Sexual Experience, and (d) Advanced Sexual Experience. The second set, interpersonal risk, examined (a) Victimization, (b) Anticipated Partner Reaction, (c) Birth Control Sexual Assertiveness, (d) Refusal Sexual Assertiveness, and (e) Initiation Sexual Assertiveness. The third set, psychoattitudinal risk, involved (a) Psychosocial Functioning, (b) Psychosexual Attitudes, and (c) Self‐Efficacy for AIDS Prevention. Substantial variance was explained using structural modeling methods, with the strongest prediction involving behavioral and interpersonal HIV risk factors. Psychoattitudinal factors were less central, although still important. The results supported and extended previous findings and suggested that the biggest HIV risk factors for women include: greater social substance use, greater sexual experience, anticipated or actual victimization, low assertiveness about requesting birth control, overly positive psychosocial attitudes, negative attitudes about sexuality, and less self‐efficacy about avoiding HIV risk.
Perceptions of AZT: Implications for Adherence to Medical Regimens1
Authors: Nannis Ellen D. , Temoshok Lydia R. , Smith Mickey , Jenkins Richard A.
Published: June 2007

One hundred and fifty‐three early stage, HIV‐infected military medical beneficiaries who were receiving zidovudine (AZT) completed a questionnaire designed to assess perceptions, expectations, and patterns of AZT use, as well as standard measures of mood states. Adherence to medical regimens, or continuing with recommended AZT therapy, was related to participants feeling that their decisions to begin AZT treatment were made without any perception of “undue pressure.” Adherence also was related to fewer and less severe side effects, less negative affect, and reports of more AZT‐related benefits. The implications of these findings for both medical and psychological interventions are discussed.
Depressive Symptoms Among HIV Positive Men: Life Stress, Coping, and Social Support1
Authors: Patterson* Thomas L. , Semple Shirley J. , Temoshok Lydia R. , Atkinson J. Hampton , McCutchan J. Allen , Straits‐Tröster Kristy A. , Chandler James L. , Grant Igor
Published: June 2007

The significance of life stress, coping, and social support was examined in relation to depressive symptomatology in a sample of 160 asymptomatic and mildly symptomatic HIV‐antibody‐positive (HIV+) men. The participants (mean age = 32 years) were interviewed about the life stress that they had experienced in the previous 6
The Effects of Social Support From Friends on Anxiety and Task Performance1
Authors: Matsuzaki Manabu , Kojo Kazunori , Tanaka Koji
Published: June 2007

The effects of social support provided by a friend on anxiety reduction and task performance were investigated. While the experimentally manipulated social support from a same‐gender friend did not reduce the subject's state anxiety and had a weak facilitating effect on task performance in comparison with that from a same‐gender stranger, the nonmanipulated, spontaneous social support of a friend reduced the subject?s state anxiety and had a facilitating effect on task performance more than in the case of the stranger's support. These results were discussed in terms of congruence in the provider's and the recipient's perceptions of social support exchanges, and in terms of the specificity model.
International Behavioral Medicine: Evolution and Future1
Authors: Harris Janel K. , Genac David S.
Published: June 2007

The development of behavioral medicine as an international phenomenon was studied by examining the national origin of all entries inBehavioral Medicine Abstracts(BMA), Volumes 1 to 10. Researchers from 44 nations have had their work cited in BMA. Twenty‐five percent of the total entries originated outside the United States. These data suggest that behavioral medicine has become an international phenomenon. The opportunity for international collaboration and exchange of information and technologies to enhance the health of people worldwide has never been greater. The formation of the International Society of Behavioral Medicine (ISBM) in 1990 launched a new era for international cooperation in behavioral medicine.
Blaming People With AIDS: Who Deserves to Be Sick?1
Authors: Schellenberg E. Glenn , Bem Sandra Lipsitz
Published: June 2007

We examined the degree to which people are blamed for having AIDS as a function of their age and factors commonly associated with HIV transmission. Heterosexual undergraduates read brief vignettes, each describing a male person with AIDS (PWA), and rated how much each PWA was to blame for having AIDS. PWAs were more likely to be blamed if they were IV‐drug users, homosexuals, over the age of 12, or if they had several sex partners. PWAs who had contact with blood products were blamed less than other PWAs, but only if they were heterosexual. Once a person was blamed for having AIDS because of IV‐drug use, factors that normally reduce blame (i.e., heterosexuality or monogamy) had less of an effect. Male respondents assigned blame more readily than females, especially to homosexuals and children.
Binge Eating Scale: Further Assessment of Validity and Reliability1
Authors: Timmerman Gayle M.
Published: June 2007

Validity of the Binge Eating Scale (BES), used to measure binge eating severity in overweight binge eaters, was examined using food records. A sample of 56 nonpurge binge eating women completed the BES and 28‐day food records. Self‐identified binges were classified as subjective when less than 1,000 calories were consumed and as objective when 1,000 calories or more were consumed. Binge severity was measured by total number of binge calories, binge episodes, and binge days over 28 days. BES scores had significant, moderate associations between subjective and objective binge eating severity. In contrast, BES scores were not related to total caloric intake. The BES was unable to distinguish between subjective and objective binge eating, which is essential for diagnostic purposes.
Psycho‐Existential Distress and Problem Behaviors: Gender, Subsample, and Longitudinal Tests1
Authors: Harlow Lisa L. , Mitchell Kimberly J. , Fitts Sherri N. , Saxon Susan E.
Published: June 2007

Results from cross‐sectional (602 college students) and longitudinal (545 community women) samples from New England converged to show multiple corroboration for a hierarchical factor model of Problem Behavior linking psycho‐existential distress with alcohol temptations and use, drug use, and AlDS‐risk behavior. The higher order factor model showed no significant gender differences for parameter estimates across cross‐sectional subsamples of 401 female and 20! male college students, and it showed only minor differences (three factor loadings) across longitudinal subsamples of 321 wider community and 224 continuing‐education women. Several longitudinal tests demonstrated strong evidence for stability of the higher order factor of Problem Behavior and of each of the four primary factors across a 1‐year period, and demonstrated some support for psycho‐existential distress preceding the remaining problem behaviors.
Psychopathology in the Eating Disorders: The Influence of Physical Activity1
Authors: Davis Caroline , Woodside D. Blake , Olmsted Marion P. , Kaptein Simone
Published: June 2007

This study was designed to examine whether high‐level exercise (HE) and starvation are associated with greater psychopathology in patients with eating disorders than either low weight or HE on its own. Patients with either anorexia nervosa or bulimia nervosa were dichotomized according to their exercise status prior to hospital admission. High‐level exercisers reported greater psychopathology than moderate/nonexercisers, and these effects were not confounded by differences in body weight. Conclusions are inevitably speculative because of the cross‐sectional nature of the data. It is probable, however, that certain psychological characteristics may foster high‐level exercising among patients who develop eating disorders, whereas other characteristics may be exacerbated by exercise in combination with starvation.
Does the Five Factor Model of Personality Apply to Smokers? A Preliminary Investigation1
Authors: Shadel William G. , Niaura Raymond , Goldstein Michael G. , Abrams David B.
Published: June 2007

The purpose of this study was to explore the relationship between the Big Five personality dimensions and smoking variables. Thirty‐seven smokers completed a standard, reliable 80‐item bipolar measure of the Big Five trait dimensions, as well as measures of nicotine dependence, smoking exposure, and quitting history. Despite finding some significant zero‐order relationships between a few of the dimensions and the smoking variables, only one of the partial correlational analyses that controlled for relationships among the personality dimensions in their associations with the nicotine dependence and smoking history variables was significant. These results indicate the need for further research on personality traits and smoking.
Sex Differences in Salivary Cortisol Levels Following Naltrexone Administration1
Authors: Klein Laura Cousino , Jamner Larry D. , Alberts Janel , Orenstein Matthew D. , Levine Linda , Leigh Hoyle
Published: June 2007

Effects of endogenous opioid peptide blockade by naltrexone on salivary Cortisol levels were examined in healthy men (n= 8) and women (n= 6). Participants received naltrexone (100 mg) during one laboratory session and a placebo pill during another session. Drug order was counterbalanced across participants. Saliva samples were collected 24 hr after each pill was administered. Among women, salivary Cortisol levels significantly increased following naltrexone administration compared with a placebo pill. Naltrexone administration did not alter salivary Cortisol levels in men. Results suggest sex differences in neuroendocrine sensitivity to opioid blockade, a finding that may hold significance with regard to the treatment of alcohol addiction with naltrexone.
Modeling, Experiment, and Fabrication of Micro-Grooved Heat Pipes: An Update
Authors: Suman Balram
Published: June 2007

The review presents an update of the work done in the micro heat pipe research and development, with an aim to give updated detailed knowledge to individuals new to the field, as well as to those already working in this area. Presented here is a summary of the recent advances in these devices occurring since the early 1990s. The following review describes the historical development of these devices, along with a review of the steady state and the transient models, sensitivity analyses, recent experimental investigations and fabrication techniques. The critical heat input, dryout length, fill charge, various heat pipe limitations and design have also been discussed in brief. Finally, future research and areas in which additional information is required are identified and delineated. This article has 204 references.
On the sound field of a shallow spherical shell in an infinite baffle
Authors: Mellow Tim , Kärkkäinen Leo
Published: June 2007

A method is presented for calculating the far field sound radiation from a shallow spherical shell in an acoustic medium. The shell has a concentrated ring mass boundary condition at its perimeter representing a loudspeaker voice coil and is excited by a concentrated ring force exerted by the end of the voice coil. A Green’s function is developed for a shallow spherical shell, which is based upon Reissner’s solution to the shell wave equation [Q. Appl. Math. 13, 279–290 (1955)]. The shell is then coupled to the surrounding acoustic medium using an eigenfunction expansion, with unknown coefficients, for its deflection. The resulting surface pressure distribution is solved using the King integral together with the free space Green’s function in cylindrical coordinates. In order to eliminate the need for numerical integration, the radiation (coupling) integrals are solved analytically to yield fast converging expansions. Hence, a set of simultaneous equations is obtained which is solved for the coefficients of the eigenfunction expansion. These coefficients are finally used in formulas for the far field sound radiation.
Improved speech recognition in noise in simulated binaurally combined acoustic and electric stimulation
Authors: Kong Ying-Yee , Carlyon Robert P.
Published: June 2007

Speech recognition in noise improves with combined acoustic and electric stimulation compared to electric stimulation alone [Kong et al., J. Acoust. Soc. Am. 117, 1351–1361 (2005)]. Here the contribution of fundamental frequency (F0) and low-frequency phonetic cues to speech recognition in combined hearing was investigated. Normal-hearing listeners heard vocoded speech in one ear and low-pass (LP) filtered speech in the other. Three listening conditions (vocode-alone, LP-alone, combined) were investigated. Target speech (average F0=120Hz) was mixed with a time-reversed masker (average F0=172Hz) at three signal-to-noise ratios (SNRs). LP speech aided performance at all SNRs. Low-frequency phonetic cues were then removed by replacing the LP speech with a LP equal-amplitude harmonic complex, frequency and amplitude modulated by the F0 and temporal envelope of voiced segments of the target. The combined hearing advantage disappeared at 10 and 15dB SNR, but persisted at 5dB SNR. A similar finding occurred when, additionally, F0 contour cues were removed. These results are consistent with a role for low-frequency phonetic cues, but not with a combination of F0 information between the two ears. The enhanced performance at 5dB SNR with F0 contour cues absent suggests that voicing or glimpsing cues may be responsible for the combined hearing benefit.
k
-space propagation models for acoustically heterogeneous media: Application to biomedical photoacoustics
Authors: Cox B. T. , Kara S. , Arridge S. R. , Beard P. C.
Published: June 2007

Biomedical applications of photoacoustics, in particular photoacoustic tomography, require efficient models of photoacoustic propagation that can incorporate realistic properties of soft tissue, such as acoustic inhomogeneities both for purposes of simulation and for use in model-based image reconstruction methods. k-space methods are well suited to modeling high-frequency acoustics applications as they require fewer mesh points per wavelength than conventional finite element and finite difference models, and larger time steps can be taken without a loss of stability or accuracy. They are also straighforward to encode numerically, making them appealing as a general tool. The rationale behind k-space methods and the k-space approach to the numerical modeling of photoacoustic waves in fluids are covered in this paper. Three existing k-space models are applied to photoacoustics and demonstrated with examples: an exact model for homogeneous media, a second-order model that can take into account heterogeneous media, and a first-order model that can incorporate absorbing boundary conditions.
Echolocation click sounds from wild inshore finless porpoise (Neophocaena phocaenoides sunameri) with comparisons to the sonar of riverine N. p. asiaeorientalis
Authors: Li Songhai , Wang Ding , Wang Kexiong , Akamatsu Tomonari , Ma Zhiqiang , Han Jiabo
Published: June 2007

Acoustic signals from wild Neophocaena phocaenoides sunameri were recorded in the waters off Liao-dong-wan Bay located in Bohai Sea, China. Signal analysis shows that N. p. sunameri produced “typical” phocoenid clicks. The peak frequencies fp of clicks ranged from 113 to 131kHz with an average of 121±3.78kHz (n=71). The 3dB bandwidths Δf ranged from 10.9 to 25.0kHz with an average of 17.5±3.30kHz. The signal durations Δt ranged from 56 to 109μs with an average 80±11.49μs. The number of cycles Nc ranged from 7 to 13 with an average of 9±1.48. With increasing peak frequency there was a faint tendency of decrease in bandwidth, which implies a nonconstant value of fp∕Δf. On occasion there were some click trains with faint click energy presenting below 70kHz, however, it was possibly introduced by interference effect from multiple pulses structures. The acoustic parameters of the clicks were compared between the investigated population and a riverine population of finless porpoise.
Contralateral influences of wideband inhibition on the effect of onset asynchrony as a cue for auditory grouping
Authors: Roberts Brian , Holmes Stephen D.
Published: June 2007

Onset asynchrony is an important cue for segregating sound mixtures. A harmonic of a vowel that begins before the other components contributes less to vowel quality. This asynchrony effect can be partly reversed by accompanying the leading portion of the harmonic with an octave-higher captor tone. The original interpretation was that the captor and leading portion formed a perceptual group, but it has recently been shown that the captor effect depends on neither a common onset time nor harmonic relations with the leading portion. Instead, it has been proposed that the captor effect depends on wideband inhibition in the central auditory system. Physiological evidence suggests that such inhibition occurs both within and across ears. Experiment 1 compared the efficacy of a pure-tone captor presented in the same or opposite ear to the vowel and leading harmonic. Contralateral presentation was at least as effective as ipsilateral presentation. Experiment 2 used multicomponent captors in a more comprehensive evaluation of harmonic influences on captor efficacy. Three captors with different fundamental frequencies were used, one of which formed a consecutive harmonic series with the leading harmonic. All captors were equally effective, irrespective of the harmonic relationship. These findings support and refine the inhibitory account.
Retrofocusing techniques in a waveguide for acoustic communications
Authors: Song H. C. , Kim S. M.
Published: June 2007

In the paper “Retrofocusing technique for high rate acoustic communications” [M. Stojanovic, J. Acoust. Soc. Am. 117, 1173–1185 (2005)], it is suggested that the time reversal approach requires a large number of array elements to compete with other approaches. Here the analysis of that paper is extended with a modified example to compare the performance of various approaches in three respects: (1) array element distribution across the water column, (2) channel normalization, and (3) phase delay across the array. In contrast, our results show that the time reversal approach combined with channel equalization can offer nearly optimal performance with a very small four element array.
Focused intracochlear electric stimulation with phased array channels
Authors: van den Honert Chris , Kelsall David C.
Published: June 2007

A method is described for producing focused intracochlear electric stimulation using an array of N electrodes. For each electrode site, N weights are computed that define the ratios of positive and negative electrode currents required to produce cancellation of the voltage within scala tympani at all of the N−1 other sites. Multiple sites can be stimulated simultaneously by superposition of their respective current vectors. The method allows N independent stimulus waveforms to be delivered to each of the N electrode sites without spatial overlap. Channel interaction from current spread associated with monopolar stimulation is substantially eliminated. The method operates by inverting the spread functions of individual monopoles as measured with the other electrodes. The method was implemented and validated with data from three human subjects implanted with 22-electrode perimodiolar arrays. Results indicate that (1) focusing is realizable with realistic precision; (2) focusing comes at the cost of increased total stimulation current; (3) uncanceled voltages that arise beyond the ends of the array are weak except when stimulating the two end channels; and (4) close perimodiolar positioning of the electrodes may be important for minimizing stimulation current and sensitivity to measurement errors.
Binaural weighting of monaural spectral cues for sound localization
Authors: Macpherson Ewan A. , Sabin Andrew T.
Published: June 2007

For human listeners, cues for vertical-plane localization are provided by direction-dependent pinna filtering. This study quantified listeners’ weighting of the spectral cues from each ear as a function of stimulus lateral angle, interaural time difference (ITD), and interaural level difference (ILD). Subjects indicated the apparent position of headphone-presented noise bursts synthesized in virtual auditory space. The synthesis filters for the two ears either corresponded to the same location or to two different locations separated vertically by 20deg. Weighting of each ear’s spectral information was determined by a multiple regression between the elevations to which each ear’s spectrum corresponded and the vertical component of listeners’ responses. The apparent horizontal source location was controlled either by choosing synthesis filters corresponding to locations on or 30deg left or right of the median plane or by attenuating or delaying the signal at one ear. For broadband stimuli, spectral weighting and apparent lateral angle were determined primarily by ITD. Only for high-pass stimuli were weighting and lateral angle determined primarily by ILD. The results suggest that the weighting of monaural spectral cues and the perceived lateral angle of a sound source depend similarly on ITD, ILD, and stimulus spectral range.
Locating air leaks in manned spacecraft using structure-borne noise
Authors: Holland Stephen D. , Chimenti D. E. , Roberts Ron , Strei Michael
Published: June 2007

All manned spacecraft are vulnerable to leaks generated by micrometeorite or debris impacts. Methods for locating such leaks using leak-generated, structure-borne ultrasonic noise are discussed and demonstrated. Cross-correlations of ultrasonic noise waveforms from a leak into vacuum are used to find the location of the leak. Four methods for sensing and processing leak noise have been developed and tested and each of these can be used to reveal the leak location. The methods, based on phased-array, distributed sensor, and dual sensor approaches, utilize the propagation patterns of guided ultrasonic Lamb waves in the spacecraft skin structure to find the source or direction of the leak noise. It is shown that each method can be used to successfully locate the leak to within a few millimeters on a 0.6-m2 aluminum plate. The relative merits of the four methods are discussed.
On the relation between the phonation threshold lung pressure and the oscillation frequency of the vocal folds
Authors: Lucero Jorge C. , Koenig Laura L.
Published: June 2007

This Letter presents an extension of a previous equation for the phonation threshold pressure by Titze [I. R. Titze, J. Acoust. Soc. Am. 83, 1536–1552 (1988)]. The extended equation contains the vocal-fold oscillation frequency as an explicit factor. It is derived from the mucosal wave model of the vocal folds by considering the general case of an arbitrary time delay for the mucosal wave to travel the glottal height. The results are illustrated with a numerical example, which shows good qualitative agreement with experimental measures.
Call repertoire of infant African elephants: First insights into the early vocal ontogeny
Authors: Stoeger-Horwath Angela S. , Stoeger Simon , Schwammer Harald. M. , Kratochvil Helmut
Published: June 2007

African savannah elephants (Loxodonta africana) have a complex acoustic communication system, but very little is known about their vocal ontogeny. A first approach in ontogenetic studies is to define the call repertoire of specific age groups. Twelve hundred calls of 11 infant elephants from neonatal to 18 months of age recorded at the Vienna Zoo in Austria and at the Daphne Sheldrick’s orphanage at the Nairobi National Park, Kenya were analyzed. Six call types were structurally distinguished: the rumble, the bark, the grunt, the roar (subdivided into a noisy-, tonal-, and mixed-roar), the snort, and the trumpet. Generally, within-call-type variation was high in all individuals. In contrast to adult elephants, the infants showed no gender-dependent variation in the structure or in the number of call types produced. Male infants, however, were more vocally adamant in their suckle behavior than females. These results give a first insight to the early vocal ontogeny and should promote further ontogenetic studies on elephants. Due to their vocal learning ability in combination with the complex fission-fusion society, elephants could be an interesting model to study the role of imitation in the vocal ontogeny of a nonprimate terrestrial mammal.
Simulation and analysis of nasalized vowels based on magnetic resonance imaging data
Authors: Pruthi Tarun , Espy-Wilson Carol Y. , Story Brad H.
Published: June 2007

In this study, vocal tract area functions for one American English speaker, recorded using magnetic resonance imaging, were used to simulate and analyze the acoustics of vowel nasalization. Computer vocal tract models and susceptance plots were used to study the three most important sources of acoustic variability involved in the production of nasalized vowels: velar coupling area, asymmetry of nasal passages, and the sinus cavities. Analysis of the susceptance plots of the pharyngeal and oral cavities, −(Bp+Bo), and the nasal cavity, Bn, helped in understanding the movement of poles and zeros with varying coupling areas. Simulations using two nasal passages clearly showed the introduction of extra pole-zero pairs due to the asymmetry between the passages. Simulations with the inclusion of maxillary and sphenoidal sinuses showed that each sinus can potentially introduce one pole-zero pair in the spectrum. Further, the right maxillary sinus introduced a pole-zero pair at the lowest frequency. The effective frequencies of these poles and zeros due to the sinuses in the sum of the oral and nasal cavity outputs changes with a change in the configuration of the oral cavity, which may happen due to a change in the coupling area, or in the vowel being articulated.
Maxwell rheological model for lipid-shelled ultrasound microbubble contrast agents
Authors: Doinikov Alexander A. , Dayton Paul A.
Published: June 2007

The present paper proposes a model that describes the encapsulation of microbubble contrast agents by the linear Maxwell constitutive equation. The model also incorporates the translational motion of contrast agent microbubbles and takes into account radiation losses due to the compressibility of the surrounding liquid. To establish physical features of the proposed model, comparative analysis is performed between this model and two existing models, one of which treats the encapsulation as a viscoelastic solid following the Kelvin-Voigt constitutive equation and the other assumes that the encapsulating layer behaves as a viscous Newtonian fluid. Resonance frequencies, damping coefficients, and scattering cross sections for the three shell models are compared in the regime of linear oscillation. Translational displacements predicted by the three shell models are examined by numerically calculating the genera1, nonlinearized equations of motion for weakly nonlinear excitation. Analogous results for free bubbles are also presented as a basis to which calculations made for encapsulated bubbles can be related. It is shown that the Maxwell shell model possesses specific physical features that are unavailable in the two other models.
Violin f-hole contribution to far-field radiation via patch near-field acoustical holography
Authors: Bissinger George , Williams Earl G. , Valdivia Nicolas
Published: June 2007

The violin radiates either from dual ports (f-holes) or via surface motion of the corpus (top+ribs+back), with no clear delineation between these sources. Combining “patch” near-field acoustical holography over just the f-hole region of a violin with far-field radiativity measurements over a sphere, it was possible to separate f-hole from surface motion contributions to the total radiation of the corpus below 2.6kHz. A0, the Helmholtz-like lowest cavity resonance, radiated essentially entirely through the f-holes as expected while A1, the first longitudinal cavity mode with a node at the f-holes, had no significant f-hole radiation. The observed A1 radiation comes from an indirect radiation mechanism, induced corpus motion approximately mirroring the cavity pressure profile seen for violinlike bowed string instruments across a wide range of sizes. The first estimates of the fraction of radiation from the f-holes Ff indicate that some low frequency corpus modes thought to radiate only via surface motion (notably the first corpus bending modes) had significant radiation through the f-holes, in agreement with net volume changes estimated from experimental modal analysis. Ff generally trended lower with increasing frequency, following corpus mobility decreases. The f-hole directivity (top/back radiativity ratio) was generally higher than whole-violin directivity.
Do acoustic features of lion,Panthera leo, roars reflect sex and male condition?
Authors: Pfefferle Dana , West Peyton M. , Grinnell Jon , Packer Craig , Fischer Julia
Published: June 2007

Long distance calls function to regulate intergroup spacing, attract mating partners, and/or repel competitors. Therefore, they may not only provide information about the sex (if both sexes are calling) but also about the condition of the caller. This paper provides a description of the acoustic features of roars recorded from 18 male and 6 female lions (Panthera leo) living in the Serengeti National park, Tanzania. After analyzing whether these roars differ between the sexes, tests whether male roars may function as indicators of their fighting ability or condition were conducted. Therefore, call characteristics were tested for relation to anatomical features as size, mane color, or mane length. Call characteristics included acoustic parameters that previously had been implied as indicators of size and fighting ability, e.g., call length, fundamental frequency, and peak frequency. The analysis revealed differences in relation to sex, which were entirely explained by variation in body size. No evidence that acoustic variables were related to male condition was found, indicating that sexual selection might only be a weak force modulating the lion’s roar. Instead, lion roars may have mainly been selected to effectively advertise territorial boundaries.
Ocean acoustic interferometry
Authors: Brooks Laura A. , Gerstoft Peter
Published: June 2007

Ocean acoustic interferometry refers to an approach whereby signals recorded from a line of sources are used to infer the Green’s function between two receivers. An approximation of the time domain Green’s function is obtained by summing, over all source positions (stacking), the cross-correlations between the receivers. Within this paper a stationary phase argument is used to describe the relationship between the stacked cross-correlations from a line of vertical sources, located in the same vertical plane as two receivers, and the Green’s function between the receivers. Theory and simulations demonstrate the approach and are in agreement with those of a modal based approach presented by others. Results indicate that the stacked cross-correlations can be directly related to the shaded Green’s function, so long as the modal continuum of any sediment layers is negligible.
Effects of masker-spectral variability and masker fringes in children and adults
Authors: Leibold Lori J. , Neff Donna L.
Published: June 2007

This study examined the degree to which masker-spectral variability contributes to children’s susceptibility to informational masking. Listeners were younger children (5–7 years), older children (8–10 years), and adults (19–34 years). Masked thresholds were measured using a 2IFC, adaptive procedure for a 300-ms, 1000-Hz signal presented simultaneously with (1) broadband noise, (2) a random-frequency ten-tone complex, or (3) a fixed-frequency ten-tone complex. Maskers were presented at an overall level of 60dB SPL. Thresholds were similar across age for the noise condition. Thresholds for most children were higher than for most adults, however, for both ten-tone conditions. The average difference in threshold between random and fixed ten-tone conditions was comparable across age, suggesting a similar effect of reducing masker-spectral variability in children and adults. Children appear more likely to be susceptible to informational masking than adults, however, both with and in the absence of masker-spectral variability. The addition of a masker fringe (delayed onset of signal relative to masker) provided a release from masking for fixed and random ten-tone conditions in all age groups, suggesting at least part of the masking observed for both ten-tone maskers was informational.
Acoustic scattering by a rigid elliptic cylinder in a slightly viscous medium
Authors: Scharstein Robert W. , Davis Anthony M. J.
Published: June 2007

A complete solution is obtained for the two-dimensional diffraction of a time-harmonic acoustic plane wave by an impenetrable elliptic cylinder in a viscous fluid. Arbitrary size, ellipticity, and angle of incidence are considered. The linearized equations of viscous flow are used to write down expressions for the dilatation and vorticity in terms of products of radially and angular dependent Mathieu functions. The no-slip condition on the rigid boundary then determines the coefficients. The resulting computations are facilitated by recently developed library routines for complex input parameters. The solution for the circular cylinder serves as a guide and a differently constructed solution for the strip is also given. Typical results in the “resonant” range of dimensionless wave number, displaying the surface vorticity and the far-field scattering pattern are included, with the latter allowing comparison with the inviscid case.
The effect of emphatic stress on consonant vowel coarticulation
Authors: Lindblom Björn , Agwuele Augustine , Sussman Harvey M. , Cortes Elisabet Eir
Published: June 2007

This study assessed the acoustic coarticulatory effects of phrasal accent on [V1.CV2] sequences, when separately applied to V1 or V2, surrounding the voiced stops [b], [d], and [g]. Three adult speakers each produced 360 tokens (six V1 contexts×ten V2 contexts×three stops×two emphasis conditions). Realizing that anticipatory coarticulation of V2 onto the intervocalic C can be influenced by prosodic effects, as well as by vowel context effects, a modified locus equation regression metric was used to isolate the effect of phrasal accent on consonantal F2 onsets, independently of prosodically induced vowel expansion effects. The analyses revealed two main emphasis-dependent effects: systematic differences in F2 onset values and the expected expansion of vowel space. By accounting for the confounding variable of stress-induced vowel space expansion, a small but consistent coarticulatory effect of emphatic stress on the consonant was uncovered in lingually produced stops, but absent in labial stops. Formant calculations based on tube models indicated similarly increased F2 onsets when stressed /d/ and /g/ were simulated with deeper occlusions resulting from more forceful closure movements during phrasal accented speech.
Numerical investigation of elastic modes of propagation in helical waveguides
Authors: Treyssède Fabien
Published: June 2007

Steel multi-wire cables are widely employed in civil engineering. They are usually made of a straight core and one layer of helical wires. In order to detect material degradation, nondestructive evaluation methods based on ultrasonics are one of the most promising techniques. However, their use is complicated by the lack of accurate cable models. As a first step, the goal of this paper is to propose a numerical method for the study of elastic guided waves inside a single helical wire. A finite element (FE) technique is used based on the theory of wave propagation inside periodic structures. This method avoids the tedious writing of equilibrium equations in a curvilinear coordinate system yielding translational invariance along the helix centerline. Besides, no specific programming is needed inside a conventional FE code because it can be implemented as a postprocessing step of stiffness, mass and damping matrices. The convergence and accuracy of the proposed method are assessed by comparing FE results with Pochhammer-Chree solutions for the infinite isotropic cylinder. Dispersion curves for a typical helical waveguide are then obtained. In the low-frequency range, results are validated with a helical Timoshenko beam model. Some significant differences with the cylinder are observed.
Training native English speakers to identify Japanese vowel length contrast with sentences at varied speaking rates
Authors: Hirata Yukari , Whitehurst Elizabeth , Cullings Emily
Published: June 2007

Native English speakers were trained to identify Japanese vowel length in three types of training differing in sentential speaking rate: slow-only, fast-only, and slow-fast. Following Pisoni and Lively’s high phonetic variability hypothesis [Pisoni, D. B., and Lively, S. E., Speech Perception and Linguistic Experience, 433–459 (1995)], higher stimulus variability by means of training with two rates was hypothesized to aid learners in adapting to speech rate variation more effectively than training with only one rate. Trained participants identified the length of the second vowel of disyllables, short or long, embedded in a sentence of the respective rate, and received immediate feedback. The three trained groups’ abilities before and after training were examined with tests containing sentences of slow, normal, and fast rates, and were compared with those of a control that was not trained. A robust effect of slow-fast training, a marginal effect of slow-only training, but no significant effect of fast-only training were found in the overall test scores. Slow-fast and slow-only training showed small advantages over fast-only training on the fast-rate test scores, while effects for all three training types were found on the slow- and normal-rate test scores. The degree to which the results support the high phonetic variability hypothesis is discussed.
Distortion product otoacoustic emission suppression tuning and acoustic admittance in human infants: Birth through 6 months
Authors: Abdala Carolina , Keefe Douglas H. , Oba Sandra I.
Published: June 2007

Previous work has reported non-adultlike distortion product otoacoustic emission (DPOAE) suppression in human newborns at f2=6000Hz, indicating an immaturity in peripheral auditory function. In this study, DPOAE suppression tuning curves (STCs) were recorded as a measure of cochlear function and acoustic admittance/reflectance (YR) in the ear canal recorded as a measure of middle-ear function, in the same 20 infants at birth and through 6 months of age. DPOAE STCs changed little from birth through 6 months, showing excessively narrow and sharp tuning throughout the test period. In contrast, several middle-ear indices at corresponding frequencies shifted systematically with increasing age, although they also remained non-adultlike at 6 months. Linear correlations were conducted between YR and DPOAE suppression features. Only two correlations out of 76 were significant, and all but three YR variables accounted for <10% of the variance in DPOAE suppression tuning. The strongest correlation was noted between admittance phase at 5700Hz and STC tip-to-tail (R=0.49). The association between middle-ear variables and DPOAE suppression may be stronger during other developmental time periods. Study of older infants and children is needed to fully define postnatal immaturity of human peripheral auditory function.
Modeling the detection range of fish by echolocating bottlenose dolphins and harbor porpoises
Authors: Au Whitlow W. L. , Benoit-Bird Kelly J. , Kastelein Ronald A.
Published: June 2007

The target strength as a function of aspect angle were measured for four species of fish using dolphin-like and porpoise-like echolocation signals. The polar diagram of target strength values measured from an energy flux density perspective showed considerably less fluctuation with azimuth than would a pure tone pulse. Using detection range data obtained from dolphin and porpoise echolocation experiments, the detection ranges for the Atlantic cod by echolocating dolphins and porpoises were calculated for three aspect angles of the cod. Maximum detection ranges occurred when the fish was broadside to the odontocete and minimum detection ranges occurred when the cod was in the tail aspect. Maximum and minimum detection ranges for the bottlenose dolphin in a noise-limited environment was calculated to be 93 and 70m, respectively. In a quiet environment, maximum and minimum detection ranges for the bottlenose dolphin were calculated to be 173 and 107m, respectively. The detection ranges for the harbor porpoise in a quiet environment were calculated to be between 15 and 27m. The primary reason for the large differences in detection ranges between both species was attributed to the 36dB higher source level of the bottlenose dolphin echolocation signals.