bluuebunny/crossref_metadata_2025 huggingface dataset:
Environment-dependent interfacial strength using first principles thermodynamics: The example of the Pt-HfO2 interface
Authors: Cardona Quintero Y. , Ramanath Ganpati , Ramprasad R.
Published: October 2013

A parameter-free, quantitative, first-principles methodology to determine the environment-dependent interfacial strength of metal-metal oxide interfaces is presented. This approach uses the notion of the weakest link to identify the most likely cleavage plane, and first principles thermodynamics to calculate the average work of separation as a function of the environment (in this case, temperature and oxygen pressure). The method is applied to the case of the Pt-HfO2 interface, and it is shown that the computed environment-dependent work of separation is in quantitative agreement with available experimental data.
Intertidal crab burrows as a low-tide refuge habitat for a specific gobiid: preliminary evidence for commensalism
Authors: Wasserman R. J. , Mostert B. P.
Published: October 2013

Mud crab (Scylla serrata) burrows in an estuarine mangrove intertidal zone were identified as potential microhabitats for small fishes. The pool-like habitats, created by these burrows, were sampled for fishes during nocturnal and diurnal low tide events, over the new moon period. A total of 1103 fish, comprising a single gobiid species (Redigobius dewaali), were collected from eight burrow-pools. The utilisation of these burrow-pools by large numbers of a single ichthyofaunal species suggests that there is a degree of commensalism between S. serrata and R. dewaali in these intertidal habitats.
When Being Narrow Minded is a Good Thing: Locally Biased People Show Stronger Contextual Cueing
Authors: Bellaera Lauren , von Mühlenen Adrian , Watson Derrick G.
Published: October 2013

Repeated contexts allow us to find relevant information more easily. Learning such contexts has been proposed to depend upon either global processing of the repeated contexts, or alternatively processing of the local region surrounding the target information. In this study, we measured the extent to which observers were by default biased to process towards a more global or local level. The findings showed that the ability to use context to help guide their search was strongly related to an observer's local/global processing bias. Locally biased people could use context to help improve their search better than globally biased people. The results suggest that the extent to which context can be used depends crucially on the observer's attentional bias and thus also to factors and influences that can change this bias.
Niche construction and Dreaming logic: aboriginal patch mosaic burning and varanid lizards (
Varanus gouldii
) in Australia
Authors: Bird Rebecca Bliege , Tayor Nyalangka , Codding Brian F. , Bird Douglas W.
Published: October 2013

Anthropogenic fire is a form of ecosystem engineering that creates greater landscape patchiness at small spatial scales: such rescaling of patch diversity through mosaic burning has been argued to be a form of niche construction, the loss of which may have precipitated the decline and extinction of many endemic species in the Western Desert of Australia. We find evidence to support this hypothesis relative to one keystone species, the sand monitor lizard (
Varanus gouldii
). Paradoxically,
V. gouldii
populations are higher where Aboriginal hunting is most intense. This effect is driven by an increase in
V. gouldii
densities near successional edges, which is higher in landscapes that experience extensive human burning. Over time, the positive effects of patch mosaic burning while hunting overwhelm the negative effects of predation in recently burned areas to produce overall positive impacts on lizard populations. These results offer critical insights into the maintenance of animal communities in the desert, supporting the hypothesis that the current high rate of endemic species decline among small animals may be linked to the interaction between invasive species and mid-century removal of Aboriginal niche construction through hunting and patch mosaic burning.
Disclosing the crosstalk among DNA methylation, transcription factors, and histone marks in human pluripotent cells through discovery of DNA methylation motifs
Authors: Luu Phuc-Loi , Schöler Hans R. , Araúzo-Bravo Marcos J.
Published: October 2013

Gene expression regulation is gated by promoter methylation states modulating transcription factor binding. The known DNA methylation/unmethylation mechanisms are sequence unspecific, but different cells with the same genome have different methylomes. Thus, additional processes bringing specificity to the methylation/unmethylation mechanisms are required. Searching for such processes, we demonstrated that CpG methylation states are influenced by the sequence context surrounding the CpGs. We used such a property to develop a CpG methylation motif discovery algorithm. The newly discovered motifs reveal “methylation/unmethylation factors” that could recruit the “methylation/unmethylation machinery” to the loci specified by the motifs. Our methylation motif discovery algorithm provides a synergistic approach to the differently methylated region algorithms. Since our algorithm searches for commonly methylated regions inside the same sample, it requires only a single sample to operate. The motifs that were found discriminate between hypomethylated and hypermethylated regions. The hypomethylation-associated motifs have a high CG content, their targets appear in conserved regions near transcription start sites, they tend to co-occur within transcription factor binding sites, they are involved in breaking the H3K4me3/H3K27me3 bivalent balance, and they transit the enhancers from repressive H3K27me3 to active H3K27ac during ES cell differentiation. The new methylation motifs characterize the pluripotent state shared between ES and iPS cells. Additionally, we found a collection of motifs associated with the somatic memory inherited by the iPS from the initial fibroblast cells, thus revealing the existence of epigenetic somatic memory on a fine methylation scale.
The impact of a teacher education course on pre‐service teachers' beliefs about inclusion: an international comparison
Authors: Sharma Umesh , Sokal Laura
Published: October 2013

In this comparative study, the impact of two stand‐alone university courses on pre‐service teachers' attitudes, concerns and teaching efficacy to teach in inclusive classrooms is examined. Twenty‐eight pre‐service teachers (PSTs) from Australia and 60 PSTs from Canada completed a survey at pre‐ and post‐stages of the course. It was found that after completion of the course, Australian participants' attitudes improved, their concerns declined, and they became more confident in their ability to teach in inclusive classrooms. Similarly, Canadian participants' concerns declined and their teaching efficacy improved, but they became more apprehensive about teaching in inclusive classrooms. Relationships among the three variables (attitudes, concerns and teaching efficacy) were examined at pre‐ and post‐test stages for both cohorts to understand how they interacted within each of the two countries. Implications of the findings for teacher education are discussed.
Methodological reflections on transference and countertransference in geographical research: relocation experiences from post‐disaster Christchurch, Aotearoa New Zealand
Authors: Hutcheson Gail
Published: October 2013

This article contributes to the emerging cannon of work on emotion and affect by extending conversations on reflexivity to include a relational ontology. I draw on geographical literature and the psychoanalytic concepts of transference and countertransference to examine how a combination of unconscious, subconscious and embodied experiences can further inform research interactions. Emotion and affect are examined in the research setting that moves beyond the clinical encounter to bring forms of unconscious communication into the realm of the everyday. The experiences that participants draw on are often beyond language and symbolisation, but are simultaneously situated in the body and its relations with other bodies. Examples are based on a qualitative research project exploring the relocation experiences of disaster survivors from Christchurch's major earthquake on 22 February 2011. The article concludes that, by focusing on transference and countertransference, unconscious and embodied connections can be fore‐grounded. Research, then, becomes a cooperative space where the researcher and the participants form a knowledge framework that includes senses, emotion and affect.
The impact of the International Association of Diabetes and Pregnancy Study Groups (IADPSG) fasting glucose diagnostic criterion on the prevalence and outcomes of gestational diabetes mellitus in Han Chinese women
Authors: Liao S. , Mei J. , Song W. , Liu Y. , Tan Y.‐D. , Chi S. , Li P. , Chen X. , Deng S.
Published: October 2013

Aims

The International Association of Diabetes and Pregnancy Study Groups (IADPSG) proposed that a one‐time value of fasting plasma glucose of 5.1 mmol/l or over at any time of the pregnancy is sufficient to diagnose gestational diabetes. We evaluated the repercussions of the application of this threshold in pregnant Han Chinese women.

Methods

This is a retrospective study of 5360 (72.3% of total) consecutively recruited pregnant Han Chinese women in one centre from 2008 to 2011. These women underwent a two‐step gestational diabetes diagnostic protocol according to the previous American Diabetes Association criteria. The IADPSG fasting plasma glucose criterion was used to reclassify these 5360 women. The prevalence, clinical characteristics and obstetric outcomes were compared among the women classified as having gestational diabetes by the previous American Diabetes Association criteria (approximately 90% were treated), those reclassified as having gestational diabetes by the single IADPSG fasting plasma glucose criterion (untreated), but not as having gestational diabetes by the previous American Diabetes Association criteria, and those with normal glucose tolerance.

Results

There were 626 cases of gestational diabetes defined by the previous American Diabetes Association criteria (11.7%) and these cases were associated with increased risks of maternal and neonatal outcomes when compared with the women with normal glucose tolerance. With the IADPSG fasting plasma glucose criterion, another 1314 (24.5%) women were reclassified as having gestational diabetes. Gestational diabetes classified by the IADPSG fasting plasma glucose criterion was associated with gestational hypertension (P = 0.0094) and neonatal admission to nursery (P = 0.035) prior to adjustment for maternal age and BMI, but was no longer a predictor for adverse pregnancy outcomes after adjustment.

Conclusion

The simple IADPSG fasting plasma glucose criterion increased the Chinese population with gestational diabetes by 200%. The increased population with gestational diabetes was not significantly associated with excess obstetric and neonatal morbidity.
Expression of the stem cell marker, SOX2, in ameloblastoma and dental epithelium
Authors: Juuri Emma , Isaksson Sanna , Jussila Maria , Heikinheimo Kristiina , Thesleff Irma
Published: October 2013

Ameloblastomas are locally invasive odontogenic tumors that exhibit a high rate of recurrence and often associate with the third molars. They are suggested to originate from dental epithelium because the tumor cells resemble epithelial cells of developing teeth. Expression of the transcription factor SOX2 has been previously localized in epithelial stem and progenitor cells in developing teeth as well as in various tumors. Here, we show that SOX2 is expressed in the epithelial cells of follicular and plexiform ameloblastomas. SOX2 was localized in the dental lamina of developing human primary molars. It was also expressed in the fragmented dental lamina associated with the third molars and in the epithelium budding from its posterior aspect in mice. However, no SOX2 expression was detected in either Hertwig's epithelial root sheath directing the formation of roots or in the epithelial cell rests of Malassez covering the completed roots. SOX2 was associated with supernumerary tooth formation in odontoma‐like tumors induced by Wnt signal activation in mice. We propose that SOX2 functions in maintaining the progenitor state of epithelium in ameloblastomas and that ameloblastomas may originate from SOX2‐expressing dental lamina epithelium.
Influence of Racial Differences on Outcomes after Thrombolytic Therapy in Acute Ischemic Stroke
Authors: Mishra Nishant K. , Mandava Pitchaiah , Chen Christopher , Grotta James , Lees Kennedy R. , Kent Thomas A.
Published: October 2013

Background

The National Institutes of Neurological Disorders and Stroke and the European Co-operative Acute Stroke III trials enrolled a largely Caucasian population, but the results are often extrapolated onto non-Caucasians. A limited number of nonrandomized studies have proposed that non-Caucasian patients show differential response to tissue plasminogen activator.

Aims and/or hypothesis

We examined if non-Caucasian patients of mixed national origin within the Virtual International Stroke Trials Archives neuroprotection trials responded differently to tissue plasminogen activator compared with Caucasians.

Methods

We matched patients within each race-subtype for age, baseline National Institutes of Health Stroke Scales, and diabetes status, and excluded outliers. We tested for an interaction of race ethnicity with tissue plasminogen activator on predicting outcomes at α = 0·05. We compared 90-day ordinal outcome (modified Rankin Scale; primary analysis) and dichotomized outcomes (modified Rankin Scale 0–1; modified Rankin Scale 0–2; survival) within individual race ethnicity.

Results

One thousand nine hundred forty-six thrombolysed patients (125 Blacks, 39 Asians, and 1821 Caucasians) were matched with 1946 non-thrombolysed patients in each race ethnicity group. Postmatching, there were no imbalances in baseline National Institutes of Health Stroke Scales and age between the groups ( P > 0·05). The interaction of tissue plasminogen activator with race ethnicity was nonsignificant in ordinal ( P = 0·4) and in dichotomized outcome models ( P > 0·05). Ordinal odds for improved outcomes were 1·5 for all patients ( P < 0·05). Ordinal odds for Caucasians were 1·5 ( P < 0·05); for Blacks, 2·1 ( P < 0·05); and for Asians, 1·2 ( P > 0·05; 1·6 after 1:2 matching with nonthrombolysed, because of small numbers). Dichotomized functional outcomes improved after thrombolysis overall, in Caucasians, in Blacks (modified Rankin Scale 0–2 only), and in Asians (after 1:2 matching; P > 0·05). Odds for survival were consistent across all groups.

Conclusions

These results do not suggest a differential response to tissue plasminogen activator based on race ethnicity. Among Asians, data were particularly sparse, and results should be interpreted with caution.
Recycling Rates of Aluminum in the United States
Authors: Chen Wei‐Qiang
Published: October 2013

Recycling rates of aluminum are defined in different (sometimes inconsistent) ways and poorly quantified. To address this situation, the definitions and calculation methods of four groups of indicators are specified for the United States: (1) indicators used to measure recycling efficiencies of old aluminum scrap at the end‐of‐life (EOL) stage, including EOL collection rate (CR), EOL processing rate, EOL recycling rate, and EOL domestic recycling rate; (2) indicators used to compare generation or use of new with old scrap, including new to old scrap ratio, new scrap ratio (NSR), and old scrap ratio; (3) indicators used to compare production or use of primary aluminum with secondary aluminum, including four recycling input rates (RIRs); and (4) indicators used to track the sinks of aluminum metal in the U.S. anthroposphere. I find that the central estimate of EOL CR varies between 38% and 65% in the United States from 1980 to 2009 and shares a relatively similar historical trend with the primary aluminum price. The RIR is shown to be significantly reduced if excluding secondary aluminum produced from new scrap resulting from the relatively high NSR. In 2003, a time when approximately 73% of all of the aluminum produced globally since 1950 was considered to still be “in service,” approximately 68% to 69% of all metallic aluminum that had entered the U.S. anthroposphere since 1900 was still in use: 67% in domestic in‐use stock and 1% to 2% exported as scrap. Only 6% to 7% was definitely lost to the environment, although the destination of 25% of the aluminum was unknown. It was either exported as EOL products, was currently hibernating, or was lost during collection.
Anatomical comparison of sciatic nerves between adults and newborns: clinical implications for ultrasound guided block
Authors: Reinoso‐Barbero Francisco , Saavedra Barbara , Segura‐Grau Elena , Llamas Alfonso
Published: October 2013

The sciatic nerve (SN) is easily blocked under ultrasound guidance by identifying either the SN common trunk or its two components: the tibial nerve (TN) and the common peroneal nerve (CPN). The authors investigate whether there are anatomical differences between newborns and adults. The SN, TN and CPN of both lower extremities in 24 (11 neonatal and 13 adults) formolized cadavers were dissected. Distances were measured from the origin of the SN (passing under the piriformis muscle) to its division into TN and CPN, and from there to the popliteal crease. The sciatic/thigh coefficient (proportion relating SN length to thigh length) and the variation coefficient for the SN were calculated. The distance from the popliteal crease to the SN division was significantly shorter in neonates than in adults (1.04 ± 0.9 cm vs. 5.6 ± 5.1 cm, P = 0.0003). In addition, the neonatal SN divided at a proportionally more distal position in the thigh than it did in adults (86 ± 13 vs. 74 ± 15%, P = 0.0059). However, the coefficient of variation between the SN‐division distances was not statistically different in infants and adults (12.8 vs. 18.2%, P = 0.4345). The variations in the point of SN division seen in the adult SN are already seen in the neonatal period, but in newborns the SN divided in a more distal position in relation to the thigh than in adults, so this finding of anatomical variability in neonates suggests that ultrasound guidance can be useful when performing a SN block in these small patients.
In vitro antifungal susceptibility of clinical isolates of Arthrographis kalrae, a poorly known opportunistic fungus
Authors: Sandoval‐Denis Marcelo , Giraldo Alejandra , Sutton Deanna A. , Fothergill Annette W. , Guarro Josep
Published: October 2013

The in vitro antifungal activity of amphotericin B (AMB), itraconazole, voriconazole, posaconazole, terbinafine (TRB), caspofungin, anidulafungin and micafungin were evaluated by a broth microdilution technique against 22 isolates of Arthrographis kalrae of clinical origin. TRB showed the highest activity, followed by the azoles, particularly posaconazole. AMB exerted low activity whereas the echinocandins showed almost no antifungal activity.
Hard times in Apia? Urban landlessness and the church in Samoa
Authors: Thornton Alec , Binns Tony , Kerslake Maria Talaitupu
Published: October 2013

This paper presents findings from a study about the relationships between social change and settlement change in Samoa, where a form of landlessness is emerging in low income areas of the main town, Apia. It examines changing reciprocal kinship arrangements with respect to customary rural village plantation land and changes in both individual and household relationships with the church. Although these relationships are typically closely bound in Pacific island societies, recent field‐based research has revealed the expansion of landless urban settlements with households that are alienated from rural village‐based kin and, by extension, customary land.
Effect of substrate bias and oxygen partial pressure on properties of RF magnetron sputtered HfO2 thin films
Authors: Maidul Haque Sk. , Sagdeo Pankaj R. , Balaji Shanmugam , Sridhar Kalavathi , Kumar Sanjiv , Bhattacharyya Debarati , Bhattacharyya Dibyendu , Sahoo Naba K.
Published: October 2013

Among all dielectric materials, hafnium oxide qualifies to be one of the most significant candidates as high index optical coating material due to its excellent chemical and thermal stability with SiO2, the low refractive index material, apart from its excellent laser radiation resistance. In this article, microstructural, physical, and optical properties of two sets of hafnium oxide thin films deposited by radio frequency (RF) magnetron reactive sputtering under a mixed ambient of argon and oxygen have been investigated: one set at various oxygen partial pressure and with substrate biasing by 50 W pulse direct current (DC) and another set at similar gaseous ambient as above but without any substrate bias. Structure of all the HfO2 thin films have been found to be monoclinic through grazing incidence x-ray diffraction measurements. Mass density of the samples has been estimated by grazing incidence x-ray reflectivity measurements and compared with the atom density of the samples estimated through Rutherford back scattering study. The evolutions of optical properties of the films with respect to the variation of oxygen partial pressure and substrate biasing have been investigated by transmission spectrophotometry and spectroscopic ellipsometry. It has been observed that RF sputtering with pulse DC substrate bias and with 15–30% oxygen partial pressure in the ambient helps in achieving better quality HfO2 films with low void fraction and high refractive index.
A simple proof of Bell's inequality
Authors: Maccone Lorenzo
Published: October 2013

Bell’s theorem is a fundamental result in quantum mechanics: it discriminates between quantum mechanics and all theories where probabilities in measurement results arise from the ignorance of pre-existing local properties. We give an extremely simple proof of Bell's inequality; a single figure suffices. This simplicity may be useful in the unending debate over what exactly the Bell inequality means, because the hypotheses underlying the proof become transparent. It is also a useful didactic tool, as the Bell inequality can be explained in a single intuitive lecture.
A phonetic study of guttural laryngeals with data from Semitic
Authors: Shahin Kimary
Published: October 2013

Phonetic data from Hebrew and Arabic were examined to determine if laryngeal consonants in those languages have tongue root articulation. This was done in search of an articulatory basis for the phonological patterning of Semitic laryngeals with tongue root consonants like pharyngeals and uvulars. This issue has been problematic for phonological theory because a theoretically comfortable phonetic basis for that patterning has not yet been identified [J. J. McCarthy, Pap. Lab. Phonol. III, 191–234 (1994); F. Nolan, ibid. IV, 361–367 (1995)]. The present study is the first to address the problem with clear natural-language data. Acoustic and articulatory data are presented (digital audio and video, waveform, spectrogram and video picture) from two laryngoscopic films: Prof. A. Laufer’s film of Hebrew and Arabic speech recorded at Haskins Labs in the early 1980s, and a new film of Arabic speech recorded at Speech Technology Research. The data show no tongue root articulation for the laryngeals. The implications for phonology are discussed. Note: Thanks to Prof. Laufer and Haskins Labs for permission to use the Haskins film, and to Prof. John Esling for collaboration in recording the new Arabic data. [Work supported by a SSHRCC grant to J. Esling.]
Range estimation of broadband noise sources in an ocean waveguide using the array invariant
Authors: Lee Sunwoong , Makris Nicholas C.
Published: October 2013

A method is developed for range estimation of broadband noise sources in a horizontally stratified ocean waveguide without a priori knowledge of the environment. It has previously been shown that the range of a transient source can be estimated using the ‘‘array invariant’’ method by analyzing instantaneous beam-time intensity data [Lee and Makris, J. Acoust. Soc. Am. 116, 2646 (2004)]. This method is now extended to range estimation of continuous, broadband noise sources in an ocean waveguide. It is shown that the cross-correlation of instantaneous beam-time intensity asymptotically reaches the array invariant. The range of the source can then be determined without knowledge of the environmental parameters. This method is applied to localize multiple uncorrelated noise sources in a horizontally stratified ocean waveguide without ambiguity.
An investigation of Columbia College Chicago reverberation chamber
Authors: Shannon Ryan P. , Fowler Kevin A. , Hill Jeremy J. , Terry Sean D. , Carney Melinda J. , Cheenne Dominique J.
Published: October 2013

The Audio Arts and Acoustics department at Columbia College in Chicago acquired a new building in 2003. The facility, a former bank, contained an old steel and concrete vault that was converted to a reverberation chamber. The acoustic properties of the space, including reverberation time, modal density, and early reflection maps were analyzed and compared to a computer model. Reflectograms were predicted at various locations and compared to test data acquired with Time Delay Spectrometry (TDS). Polar Energy Time (PET) techniques were also used to identify the location of a single 4×4 sample of foam absorber and the results of the test were compared to the predicted value from the computer model. The results of the tests show that, under its current configuration, the room is usable as a reverberation chamber down to 300 Hz, and that the computer model was able to accurately predict the results from the PET methodology.
Acoustic modeling in rectangular rooms with impedance using the finite element method with the Dirichlet-to-Neumann map
Authors: Naka Yusuke , Oberai Assad A. , Shinn-Cunningham Barbara G.
Published: October 2013

Computational models of head-related transfer functions (HRTFs) are useful in investigating the effects of echoes and reverberations in enclosures. These models may be computed at relatively low cost by geometric methods, such as the image source method. However, geometric methods typically ignore several important physical effects, such as diffraction, which effect the fidelity of the resulting HRTF. On the other hand, methods based on solving the wave equation, such as the finite element method, include these effects but tend to be computationally expensive. This study represents a Dirichlet-to-Neumann (DtN) map which significantly reduces the costs associated with using the the finite element method for computing HRTFs in a rectangular room, by analytically eliminating empty regions of the room. The DtN map for rooms with realistic impedance boundary conditions is developed. This work represents an extension of our previous approach for sound-hard rooms [Y. Naka, A.A. Oberai, and B.G. Shinn-Cunningham, Proc. 18th International Congress on Acoustics, Vol. IV, pp. 2477–2480 (2004)]. [Work supported by AFOSR.]
Sampling methods for decay time evaluation in acoustically coupled spaces
Authors: Jasa Tomislav , Xiang Ning , Kleiner Mendel
Published: October 2013

This paper applies the methods of Bayesian inference to the estimation of decay times in coupled rooms. Previous papers [N. Xiang and P. M. Goggans, J. Acoust. Soc. Am. 110, 1415–1424 (2001); 113, 2685–2697 (2003)] developed a solution method to estimate the decay times and the number of decay modes in terms of measured Schroeder’s decay functions. This paper extends the previous work by using statistical sampling methods to efficiently determine the decay times along with error estimates and evaluate the ‘‘Bayesian evidence’’ term used in determining the number of decay modes. This paper discusses the implemented methods together with the previous work to solve the problem of decay time estimation as well as determining the number of decay modes in acoustically coupled rooms.
How do you know what an animal can hear?
Authors: Heffner Henry E.
Published: October 2013

The comparative study of hearing is based on the ability to obtain valid behavioral measures of hearing in different species. This requires careful generation and measurement of sound, a behavioral task and reinforcer appropriate for the species, and a comparable definition of threshold. For audiograms, it is important to generate artifact-free pure tones and test with the animal’s head fixed in a free-field sound field. For sound localization, a two-point discrimination with the animals head fixed in the sound field is commonly used. For all discriminations, it is important to obtain data for stimuli that are below threshold to ensure that an animal is not using extraneous cues. Descriptions of techniques should be sufficiently detailed to allow other researchers to replicate them; new techniques can be calibrated by replicating the results of others. Behavioral procedures that work well with one species may not elicit optimal performance from others. Although performance should be corrected for false positives, signal detection measures are difficult to interpret and cannot compensate for the failure to keep an animal under stimulus control. In general, valid results are obtained by following good scientific practice.
The critical band and the critical ratio
Authors: Yost William A. , Shofner William
Published: October 2013

The critical band is arguably one of the most important psychophysical descriptors of auditory function. The critical ratio is often used in animal psychophysical research to estimate critical bandwidth because it is easier to obtain than estimates of critical bandwidth. However, in most cases the underlying assumptions required to use the critical ratio as an estimate of critical bandwidth are rarely met. The critical bandwidths for chinchilla and guinea pigs are similar to those obtained for human subjects, while the critical ratios are considerably higher, an observation that violates the use of the critical ratio as an estimate of critical bandwidth. This paper will describe the assumptions necessary for the critical ratio to estimate critical bandwidth. We will describe data on critical bands and critical ratios for chinchilla and guinea pigs, and we will provide evidence that the chinchilla appears to be a wideband processor of the signal in critical-ratio experiments. The inability of the chinchilla to process the signal in its narrow critical band in the critical-ratio psychophysical procedure leads to the large critical ratios. We recommend that the critical ratio not be used to estimate critical bandwidth. [Work supported by NIDCD grants to Dr. Yost and to Dr. Shofner.]
Color-Doppler guided high intensity focused ultrasound for hemorrhage control
Authors: Zderic Vesna , Rabkin Brian , Crum Lawrence , Vaezy Shahram
Published: October 2013

To determine efficacy of high intensity focused ultrasound (HIFU) in occlusion of pelvic vessels a 3.2 MHz HIFU transducer was synchronized with color-Doppler ultrasound imaging for real-time visualization of flow within blood vessels during HIFU therapy. HIFU was applied to pig and rabbit pelvic vessels in vivo, both transcutaneously and with skin removed. The in situ focal intensity was 4000 W/cm2 on average. Vessel occlusion was confirmed by color or audio Doppler, and gross and histological observations. In rabbits, five out of 10 femoral arteries (diameter of 2 mm) were occluded after 30–60 s of HIFU application. The average blood flow reduction of 40% was observed in the remaining arteries. In pigs, out of 7 treated superficial femoral arteries (2 mm in diameter), 4 were occluded, one had 80% blood flow reduction, and 2 were patent. In addition, 3 out of 4 superficial femoral arteries, punctured with 18 gauge needle, were occluded after 60–90 s of HIFU application. Larger vessels (diameter of 4 mm) were patent after HIFU treatment. Doppler-guided HIFU has potential application in occlusion of injured pelvic vessels similar to angiographic embolization.
A pulsatile flow phantom for image-guided high-intensity focused ultrasound studies on blood vessels
Authors: Greaby Robyn , Vaezy Shahram
Published: October 2013

A pulsatile flow phantom has been developed for controlled studies of acoustic hemostasis and high intensity focused ultrasound (HIFU) effects on blood vessels. The flow phantom consists of an excised carotid artery attached to a pulsatile pump and embedded in an optically and acoustically transparent gel to create an ex vivo model of a human artery. The artery was punctured with a needle to simulate percutaneous vascular injury. A HIFU transducer with a focal distance of 6 cm and a frequency of 3.33 MHz was used to treat the puncture. B-mode and power-Doppler ultrasound were used to locate the site of the puncture, target the HIFU focus, and monitor treatment. Also, the effects of vascular flow on HIFU lesions were studied by treating vessels in the phantom for different times at a variety of flows. In both studies, histology was done on the artery. In nine trials, HIFU was able to provide complete hemostasis in 55 ± 31 s. It is feasible to use the flow phantom to study acoustic hemostasis of blood vessels. Histology shows that the flow in the phantom appears to diminish the vascular damage from HIFU.
Image-guided high intensity focused ultrasound annular array for hemostasis and tumor treatment
Authors: Zderic Vesna , Held Robert , Nguyen Thuc , Vaezy Shahram
Published: October 2013

To develop and characterize an ultrasound-guided high intensity focused ultrasound (HIFU) array, an 11-element annular phased array (aperture of 3.5×6.0 cm, focal depth of 3.0–6.0 cm, frequency of 3 MHz) was coupled to an imaging probe (C9-5, Philips). LabView software was developed to control driving electronics and image guidance. Radiation force balance measurements, Schlieren imaging, and hydrophone field mapping were performed. Lesions were produced in gel phantoms, and ex vivo porcine liver and human cancerous uterus. The lesions were formed beginning at a focal depth of 6.0 cm and moving by 0.5 cm increments to 3.0 cm, and vice versa, with the overall treatment time of 2 min. The transducer had efficiency of 38%, with intensities of up to 6200 W/cm2 at the natural focus of 5 cm, in water. The 6 dB focal area varied from 0.4 mm2 (at 3 cm) to 1.5 mm2 (at 6 cm). The 3 to 6 cm tissue lesions were 2.7±0.5 cm in length, compared to 4.1±0.3 cm for the 6 to 3 cm lesions. The average lesion width was 1 cm. Image-guided HIFU array may enable treatment of large tumor volumes and hemorrhage control at different depths inside the body.
Ultrasound-guided high frequency focused ultrasound neurolysis of peripheral nerves to treat spasticity and pain
Authors: Foley Jessica L. , Starr Frank L. , Frantz Carie , Vaezy Shahram , Foley Jessica L. , Vaezy Shahram , Little James W.
Published: October 2013

Spasticity, a complication of central nervous system disorders, signified by uncontrollable muscle contractions, is difficult to treat effectively. The use of ultrasound image-guided high-intensity focused ultrasound (HIFU) to target and suppress the function of the sciatic nerve of rabbits in vivo, as a possible treatment of spasticity and pain, will be presented. The image-guided HIFU device included a 3.2-MHz spherically-curved transducer and an intraoperative imaging probe. A focal intensity of 1480−1850 W/cm2 was effective in achieving complete conduction block in 100% of 22 nerves with HIFU treatment times of 36±14 s (mean±SD). Gross examination showed blanching of the nerve at the treatment site and lesion volumes of 2.8±1.4 cm3 encompassing the nerve. Histological examination indicated axonal demyelination and necrosis of Schwann cells as probable mechanisms of nerve block. Long-term studies showed that HIFU intensity of 1930 W/cm2, applied to 12 nerves for an average time of 10.5±4.9 s, enabled nerve blocks that remained for at least 7–14 days after HIFU treatment. Histological examination showed degeneration of axons distal to the HIFU treatment site. With accurate localization and targeting of peripheral nerves using ultrasound imaging, HIFU could become a promising tool for the suppression of spasticity and pain.
Supersonic shear imaging
Authors: Fink Mathias , Tanter Mickael , Bercoff Jeremy
Published: October 2013

There is a great interest for developing in vivo quantitative imaging of the shear tissue properties. This can be achieved by using an ultrafast ultrasonic imaging device able to follow in real time the propagation of low frequency transient shear wave in the body. We have developed such an ultrafast scanner that can give up to 5.000 images/s. From the spatio-temporal evolution of the elastic field a local inversion algorithm allows to recover the shear modulus and viscosity map without the limitations induced by diffraction. Transient shear sources are induced by ultrasonic radiation pressure generated by the ultrasonic probe array. The most interesting configuration that induces high amplitude shear waves used a sonic shear source that moves at supersonic velocities. In vitro and in vivo results will be presented that demonstrate the great interest of supersonic shear imaging.
3D steady-state ultrasound-elastography
Authors: Sinkus Ralph , Bercoff Jeremy , Tanter Mickael , Fink Mathias
Published: October 2013

One of the current main limitations of Elastography is the lack of access to the full displacement field within a volume. Standard ultrasound techniques provide good motion estimation only along the ultrasound beam. These data are subsequently used for the reconstruction of elastic parameters assuming that the missing displacement components are negligible. Although feasible under certain circumstances, these assumptions typically do not hold for in-vivo applications. Thus, there is need for a technique to assess the entire displacement field in 3D. Recently, the 1D motion estimation has been extended to the measurement of the 2D displacement field [Tanter et al., IEEE Trans. Ultrason. Ferroelectr. Freq. Control 49, 1363–1374 (2002)]. This method is utilized for the assessment of the 3D displacement field by rotating and translating the US-transducer around the object of interest. Low-frequency mechanical vibrations (approx. 80 Hz) are coupled into the object from underneath (i.e., from the direction perpendicular to the plane of rotation). The measured displacement field is used to reconstruct within a volume shear elasticity and shear viscosity by local inversion of the wave equation. Contributions from the compressional wave are removed via application of the curl-operator. In-vitro results for phantoms and excised specimen are presented.
Harp design and construction
Authors: Waltham Chris
Published: October 2013

The harp is an instrument with a set of plucked strings connected directly to the sound board. Thus the requirement that the sound board be very light for efficient radiation is pitted against the requirement that the strings be tight enough to maintain harmonicity. These factors have determined the evolution of the harp since Sumerian times. As materials and construction methods have improved, strings have become tighter and sound boards lighter. Large harps have total tensions in the range of ten kilonewtons. The material of choice for the sound board, usually spruce, is pushed to the limits of its strength, and even professionally built concert harps tend not to last more than a few decades. The strings themselves are made from a variety of materials, wrapped or plain, to balance the physical requirements of tension and feel, with the acoustical demands of harmonicity and tone. Historical materials such as copper and silk have given way to steel and nylon, although gut still has a niche in the mid-range of a concert harp. These physics and engineering issues will be considered in the context of practical harp construction.
Correlation of airport noise complaint terminology with available noise metrics
Authors: Timmerman Nancy S.
Published: October 2013

In the discussion of airport noise, there is a disconnect between the language used by complainants and the acoustical terminology available to the technical community. It will be shown in what ways the complaint terminology can be described with the available noise metrics and in what ways it cannot. The complaint terminology analyzed comes from the author’s personal (previous) experience as noise control officer at Logan International Airport. Examples of some of these are (aircraft noise is): too loud, too late, too early, unending, continuous, at the wrong time, so loud it sets off car alarms, so loud I cannot hear the TV/telephone/radio, so loud it woke me up, and annoying. Terms which are not related to noise are mentioned, but not correlated. The acoustical terminology comes from the international literature and includes the standard noise metrics as well as some more recently proposed. The airport noise metrics discussed include measures of single events (maximum level, SEL, duration, signal-to-noise) and measures of noise exposure (DNL, CNEL, Leq). It is shown that while cumulative noise metrics are useful for planning and comparison, they correlate with complaint terminology less well than single event measures.
Explorative interviews as a tool for sound evaluation
Authors: Paul Stephan
Published: October 2013

Sound and noise evaluation needs to combine physical-measurements of sound with research on the interaction of the sound and the human being. For this kind of research qualitative techniques and especially explorative interviews, with the addressed people are appropriate as they consider the human being acting within this environment. The evaluation process refers to the basic concepts of qualitative research. Different forms of interviews, how to prepare and conduct an interview and not to forget about the discipline under investigation have to be considered. This clearly shows the requirement of transdisciplinarity including knowledge from disciplines like engineering sciences, social sciences and psychology. To obtain the required information on the subject under investigation within an interview the verbal ability of the addressed people has to be considered. The possibilities of transdisciplinary work, check of verbal abilities as well as approaches for basic standardization in interviews and the need for cultural adaptation will be discussed.
Investigation of the applicability of microphones to nonlinear acoustic mine detection
Authors: Fenneman Douglas , Libbey Brad
Published: October 2013

The feasibility of using microphones to measure intermodulation effects above a buried mine is under investigation at the U.S. Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate. Acoustic mine detection techniques employ acoustic energy to excite soil and buried mines. The resultant linear and nonlinear response at the surface can then be measured using non-contacting vibrometers. Carrier signal scattering by rough surfaces, however, can limit the measurement accuracy of these vibrometers and, subsequently, successful detection of the landmine. A microphone is proposed as an alternative non-contact sensor specifically for nonlinear acoustic mine detection applications. In this scenario, distinct frequency content facilitates separation of the intermodulation effects at the surface from the acoustic excitation. Experimental results employing intermodulation effects for acoustic mine detection have been reported in the literature [Donskoy et al., J. Acoust. Soc. Am. 111, 2705–2714 (2002)]. Preliminary experimental results demonstrate the ability of microphones to sense pressure radiated from soil in the presence of realistic ground velocities. The applicability of these measurements to practical mine detection systems will also be addressed.
Deduction of ground impedance using level difference measurements
Authors: Taherzadeh Shahram , Attenborough Keith
Published: October 2013

Previously, a numerical method for deducing ground-surface impedance from measurements of complex excess attenuation spectra was reported [J. Acoust. Soc. Am. 105, 2039–2042 (1999)]. Subsequent applications have predicted unrealistic values at low frequencies. Here, we report improved results using two-microphone, transfer-function measurements and discuss its merits as opposed to measuring excess attenuation in regards to a free field. Furthermore, effects of errors in measured parameters on the deduced impedance are discussed also.
Comparison of two mapping methods for computing sound propagation over irregular terrain
Authors: Di Xiao , Gilbert Kenneth E.
Published: October 2013

This paper compares a piecewise linear mapping and a cascaded conformal mapping for computing sound propagation over irregular terrain using the parabolic equation (PE) approximation. Although the piecewise linear mapping does not preserve the form of the underlying Helmholtz equation (i.e., it is not conformal), it does preserve the form of the narrow-angle PE. Further, it is shown that the correct impedance boundary condition at the ground surface can be closely approximated with the piecewise linear mapping. Compared to the cascaded conformal mapping, the piecewise mapping is extremely simple and easy to implement. It involves only a phase multiplication at the end of each range step. To test the accuracy of the piecewise linear mapping, it is compared with a cascaded conformal mapping for propagation over a single hill at various frequencies. Propagation predictions for more general terrain using the piecewise linear mapping are presented and discussed. [Work supported by the Federal Aviation Administration.]
Hearing silent shapes: Identifying the shape of a sound occluding surface
Authors: Robart Ryan L. , Rosenblum Lawrence D.
Published: October 2013

While most psychoacoustics is concerned with perception of sound sources, there is evidence that surfaces which reflect or occlude sound can also be detected and can guide behavior [e.g., M. S. Gordon and L. D. Rosenblum, J. Acoust. Soc. Am. 107, 2851 (2000)]. While there is also evidence that listeners can hear the shape of sound reflecting surfaces [e.g., C. E. Rice, Science 155, 655–664 (1967)], it is not known whether the shape of sound occluding surfaces can be heard. In a series of experiments, blindfolded listeners were asked to judge the shape of surfaces (of equal area) which occluded a set of loudspeakers emitting white noise. Overall, listeners were successful at this task, with some listeners showing near perfect performance. Follow-up experiments examined the acoustic information supportive of this skill. The findings suggest a type of auditory sensitivity not often considered in the psychoacoustics literature.
Contributions of individual components to the overall loudness of a multi-tone complex
Authors: Leibold Lori , Khaddam Samar , Jesteadt Walt
Published: October 2013

The contributions of individual components to the overall loudness of a multi-tone complex were examined in a two-interval, loudness-matching task. Stimuli were five-tone complexes centered on 1000 Hz, with six different logarithmic frequency spacings, ranging from a frequency ratio of 1.012 to 1.586. Stimuli were presented for 300 ms (10 ms rise/fall). The overall level of the standard complex was fixed at 60 dB SPL (53 dB/component). Levels of the individual components of the comparison complex were selected at random from a rectangular distribution with a range of 20 dB. Ten 100-trial blocks were run for each frequency-spacing condition. Perceptual weights were computed by calculating the point-biserial correlation between the difference in the level of each component across the two intervals and the subjects response. When all components fell within the same critical band, weights varied little across components. In contrast, the range of weights increased with increasing frequency separation, with increasing weight given to the lowest and highest frequency components. The audibility of individual components was determined by measuring detection thresholds for each component in the presence of the remaining four components. A strong relation between component weight and audibility was observed for all but the narrowest spacing conditions.