bluuebunny/crossref_metadata_2025 huggingface dataset:
Double versus single cervical cerclage for patients with recurrent pregnancy loss: A randomized clinical trial
Authors: Zolghadri Jaleh , Younesi Masoumeh , Asadi Nasrin , Khosravi Dezire , Behdin Shabnam , Tavana Zohre , Ghaffarpasand Fariborz
Published: October 2013

Aim

To compare the effectiveness of the double cervical cerclage method versus the single method in women with recurrent second‐trimester delivery.

Method

In this randomized clinical trial, we included 33 singleton pregnancies suffering from recurrent second‐trimester pregnancy loss (≥2 consecutive fetal loss during second‐trimester or with a history of unsuccessful procedures utilizing the McDonald method), due to cervical incompetence. Patients were randomly assigned to undergo either the classic McDonald method (n = 14) or the double cerclage method (n = 19). The successful pregnancy rate and gestational age at delivery was also compared between the two groups.

Results

The two study groups were comparable regarding their baseline characteristics. The successful pregnancy rate did not differ significantly between those who underwent the double cerclage method or the classic McDonald cerclage method (100% vs 85.7%; P = 0.172). In the same way, the preterm delivery rate (<34 weeks of gestation) was comparable between the two study groups (10.5% vs 35.7%; P = 0.106). Those undergoing the double cerclage method had longer gestational duration (37.2 ± 2.6 vs 34.3 ± 3.8 weeks; P = 0.016).

Conclusion

The double cervical cerclage method seems to provide better cervical support, as compared with the classic McDonald cerclage method, in those suffering from recurrent pregnancy loss, due to cervical incompetence.
Comparison of patient‐controlled analgesia versus continuous infusion of tramadol in post‐cesarean section pain management
Authors: Demirel Ismail , Ozer Ayse Belin , Atilgan Remzi , Kavak Burcin Salih , Unlu Serap , Bayar Mustafa Kemal , Sapmaz Ekrem
Published: October 2013

Aim

To evaluate and compare analgesic efficacy, drug consumption and patient satisfaction with the i.v. patient‐controlled and continuous infusion modes of administration of tramadol.

Methods

A total of 40 pregnant women in American Society of Anesthesiologists physical status classification system risk classes I–II scheduled for cesarean section were randomized into two groups to receive treatment in single‐blind fashion. Patients in both groups received tramadol as an i.v. infusion 15 min before the end of surgery under general anesthesia for cesarean section. In the post‐anesthesia care unit, the 20 patients allocated to group I were given i.v. tramadol in patient‐controlled anesthesia (PCA), while the 20 other patients assigned to group II received it as a continuous infusion. Pain visual analog scores (VAS), mean arterial pressure (MAP), heart rate, total tramadol consumption, sedation scores, side‐effects (nausea/vomiting) and patient satisfaction were evaluated seven times in the course of the first postoperative 24 h. The Mann–Whitney U‐test and Friedman's anova were used for the statistical treatment of data.

Results

VAS, sedation scores and nausea/vomiting scores were similar in both groups (P > 0.05). The 24‐h tramadol consumption was significantly lower in group I (420.15 ± 66.58 mg) than in group II (494.00 ± 29.45 mg), while patient satisfaction was significantly higher in group I (P < 0.05).

Conclusion

While tramadol administration by either of the methods used may ensure efficient early postoperative anesthesia in cesarean section patients, i.v. PCA may be preferred because of the lower drug consumption and higher patient satisfaction associated with it.
What is the success of ultrasonography of benign adnexal masses?
Authors: Bayoğlu Tekin Yeşim , Suat Dede Faruk
Published: October 2013

Aim

To assess the diagnostic accuracy of the ultrasonographic discrimination of benign adnexal masses.

Methods

This was a prospective study, evaluating 245 consecutive cases using real‐time gray‐scale ultrasonography in a tertiary education hospital.

Results

Diagnostic accuracy was high for simple cysts and solid masses as κ‐values of 0.824 and 0.816 and accuracy was moderate for endometriomas, dermoid cysts and cystadenomas as κ‐values of 0.758, 0.689 and 0.627, respectively, and low for hemorrhagic cysts as a κ‐value of 0.587. A logistic regression model was developed using ultrasonographic characteristics of the adnexal masses. Irregularity at lining of the inner wall, presence of solid component, papillary projections and echogenicity were shown to have a strong impact on the diagnosis of benign masses.

Conclusion

Although ultrasonography is a useful technique for the diagnosis of benign adnexal masses, it is limited in diagnostic accuracy. Pattern recognition is the most favored method for ultrasonographic diagnosis. Logistic regression analysis can contribute to diagnostic accuracy.
Clinical profiles of 710 premenopausal women with adenomyosis who underwent hysterectomy
Authors: Li Xuelian , Liu Xishi , Guo Sun‐Wei
Published: October 2013

Aim

The aim of this study was to determine the frequency of various symptoms and their associated characteristics in women with adenomyosis who underwent hysterectomy, and to determine which symptoms are likely to go with which others in these patients.

Material and Methods

In 2007, 1697 consecutive patients underwent hysterectomy in our hospital. Among them, 734 (43.3%) were histologically confirmed to have adenomyosis, and 710 of them were premenopausal. The medical charts of all 734 patients were retrieved, and their demographic, clinical information and postoperative findings were recorded. We used the Verbal Descriptor Scale to measure the preoperative severity of dysmenorrhea. The Apriori Algorithm was used for mining the association of different symptoms.

Results

Among the 710 premenopausal patients, only 4.5% of them had no symptoms. Dysmenorrhea was the most common complaint, occurring in 81.7% of patients. Dysmenorrhea co‐occurred most frequently with menorrhagia. The presence of adhesion, presence of endometriosis, complaint of menorrhagia, longer duration of disease, gravidity, palpable pain during pelvic examination, and diffuse adenomyosis were positively associated with the severity of dysmenorrhea. Age, severity of dysmenorrhea, and complaint of metrorrhagia were positively associated with the risk of menorrhagia.

Conclusions

Dysmenorrhea is the most common complaint in women with adenomyosis, which often goes with that of menorrhagia. Adenomyosis often co‐occurs with endometriosis and leiomyomas. Various factors are associated with the risk of having different symptoms.
Patents in the University: Priming the Pump and Crowding Out
Authors: Scotchmer Suzanne
Published: October 2013

The Bayh‐Dole Act allows universities to exploit patents on their federally sponsored research. University laboratories therefore have two sources of funds: direct grants from sponsors and income from licensing. Tax credits for private R&D also contribute, because they increase the profitability of licensing. Because Bayh‐Dole profits are a source of funds, the question arises how subsidies and Bayh‐Dole profits fit together. I show that subsidies to the university can either ‘prime the pump’ for spending out of Bayh‐Dole funds, or can crowd it out. Because of crowding out, if the sponsor wants to increase university spending beyond the university's own target, it will end up funding the entire research bill, just as if there were no profit opportunities under the Bayh‐Dole Act. A subsidy system that requires university matching can mitigate this problem.
Intellectual Property Protection and the Geography of Trade
Authors: Delgado Mercedes , Kyle Margaret , McGahan Anita M.
Published: October 2013

This paper investigates how the implementation of intellectual property rights in developing countries under the 1995 TRIPS agreement affected trade in knowledge‐intensive goods. We compare trade in knowledge‐intensive goods with trade in other types of goods for 158 members and observers of the World Trade Organization from 1993–2009. Trade in knowledge‐intensive goods increased relative to a control group after TRIPS implementation. The increase in imports by developing countries was driven by exchange with high‐income countries and was concentrated in the information and communications technology sector. Our findings suggest that the effect of TRIPS on promoting knowledge diffusion from high‐income to developing countries varies by sector.
Commitment and Consequences: Reneging on Cosponsorship Pledges in the U.S. House
Authors: Bernhard William , Sulkin Tracy
Published: October 2013

We argue that bill cosponsorship in Congress represents an institutional arrangement that provides credibility to commitments of support. We predict that if cosponsorship fosters legislative deals, MCs will only rarely back out on their pledges to support a bill if it comes up for a floor vote, and when they do, these choices will reflect strategic calculations. Further, legislators who violate their cosponsorship agreements will face punishment from colleagues, compromising their ability to gain support for their own bills. We explore the causes and effects of MCs' choices to renege on a pledge by voting no on a bill for which they were a cosponsor, focusing on all cosponsorship decisions in the 101st–108th Houses. The results reveal that patterns of reneging and its consequences are consistent with the idea that cosponsorship functions as a commitment mechanism.
The Intersection of Gender and Minority Status in National Legislatures: The Minority Women Legislative Index
Authors: Hughes Melanie M.
Published: October 2013

To date, we are unaware to what extent gains in women's legislative representation have reached minority women. To facilitate cross‐national research on minority women in politics, I present and explore new cross‐national data on the election of women and men from 431 ethnic, racial, and religious groups to national legislatures in 81 countries between 2005 and 2007. I create a new measure scoring countries by minority women's representation relative to their share of the population—the Minority Women Legislative Index (MWLI). Descriptive analyses show minority women to be substantially underrepresented in national legislatures overall but their level of exclusion varies geographically.
Elemental composition of strawberry plants inoculated with the plant growth‐promoting bacteriumAzospirillum brasilenseREC3, assessed with scanning electron microscopy and energy dispersiveX‐ray analysis
Authors: Guerrero‐Molina M. F. , Lovaisa N. C. , Salazar S. M. , Díaz‐Ricci J. C. , Pedraza R. O.
Published: October 2013

The elemental composition of strawberry plants (Fragaria ananassacv.Macarena) inoculated with the plant growth‐promoting bacteriumAzospirillum brasilenseREC3, and non‐inoculated controls, was studied using scanning electron microscopy (SEM) and energy dispersiveX‐ray (EDS) analysis. This allowed simultaneous semi‐quantification of different elements in a small, solid sample. Plants were inoculated and grown hydroponically in 50% or 100%Hoagland solution, corresponding to limited or optimum nutrient medium, respectively. Bacteria‐inoculated plants increased the growth index 45% and 80% compared to controls when grown in 100% and 50% Hoagland solution, respectively. Thus, inoculation withA. brasilenseREC3 in a nutrient‐limited medium had the strongest effect in terms of increasing both shoot and root biomass and growth index, as already described forAzospirilluminoculated into nutrient‐poor soils.SEM‐EDSspectra and maps showed the elemental composition and relative distribution of nutrients in strawberry tissues. Leaves containedC,O,N,Na,P,K,Ca andCu, while roots also hadSi andCl. The organic fraction (C,OandN) accounted for over 96.3% of the total chemical composition; of the mineral fraction, Na had higher accumulation in both leaves and roots.Azospirillum‐inoculated and control plants had similar elemental quantities; however, in bacteria‐inoculated roots,Pwas significantly increased (34.33%), which constitutes a major benefit for plant nutrition, whileCu content decreased (35.16%).
Are two threats worse than one? The effects of face race and emotional expression on fear conditioning
Authors: Bramwell Shannon , Mallan Kimberley M. , Lipp Ottmar V.
Published: October 2013

Facial cues of racial outgroup or anger mediate fear learning that is resistant to extinction. Whether this resistance is potentiated if fear is conditioned to angry, other race faces has not been established. Two groups of Caucasian participants were conditioned with two happy and two angry face conditional stimuli (CSs). During acquisition, one happy and one angry face were paired with an aversive unconditional stimulus whereas the second happy and angry faces were presented alone. CS face race (Caucasian, African American) was varied between groups. During habituation, electrodermal responses were larger to angry faces regardless of race and declined less to other race faces. Extinction was immediate for Caucasian happy faces, delayed for angry faces regardless of race, and slowest for happy racial outgroup faces. Combining the facial cues of other race and anger does not enhance resistance to extinction of fear.
Real Convergence, Capital Flows, and Competitiveness in Central and Eastern Europe
Authors: Belke Ansgar , Schnabl Gunther , Zemanek Holger
Published: October 2013

The paper scrutinizes the role of capital flows for competitiveness in the new EU member states in the context of real convergence. For this purpose it extends the seminal Balassa–Samuelson model by international capital markets to trace cyclical deviations of real exchange rates from the productivity‐driven equilibrium path. Panel estimations for the period from 1998 to 2009 reveal strong evidence for the Balassa–Samuelson effect and mixed results for the role of capital flows for international competitiveness of the Central and Eastern European countries.
Mode of International Investment and Endogenous Risk of Expropriation
Authors: Dadasov Ramin , Lorz Oliver
Published: October 2013

This paper analyzes the relationship between the mode of international investment and institutional quality. Foreign investors from a capital‐rich North can either purchase productive assets in a capital‐poor South and transfer their capital within integrated multinational firms or they can form joint ventures with local asset owners. The South is ruled by an autocratic elite that may use its political power to expropriate productive assets. The expropriation risk lowers the incentive to provide specific capital in an integrated firm and distorts the decision between joint ventures and integrated production. We determine the equilibrium risk of expropriation in this framework and the resulting pattern of international production. We also analyze as to how globalization, which is reflected in a decline in investment costs, influences institutional quality.
The Effect of Surface Roughness on Laminar Separated Boundary Layers
Authors: Simens Mark P. , Gungor Ayse G.
Published: October 2013

Roughness effects on a laminar separation bubble, formed on a flat plate boundary layer due to a strong adverse pressure gradient similar to those encountered on the suction side of typical low-pressure turbine blades, are studied by direct numerical simulation. The discrete roughness elements that have a uniform height in the spanwise direction and ones that have a height that is a function of the spanwise coordinate are modeled using the immersed boundary method. The location and the size of the roughness element are varied in order to study the effects on boundary development and turbulent transition; it was found that the size of the separation bubble can be controlled by positioning the roughness element away from the separation bubble. Roughnesses that have a height that varies in a periodic manner in the spanwise direction have a great influence on the separation bubble. The separation point is moved downstream due to the accelerated flow in the openings in the roughness element, which also prevents the formation of the recirculation region after the roughness element. The reattachment point is moved upstream, while the height of the separation bubble is reduced. These numerical experiments indicate that laminar separation and turbulent transition are mainly affected by the type, height, and location of the roughness element. Finally, a comparison between the individual influence of wakes and roughness on the separation is made. It is found that the transition of the separated boundary layer with wakes occurs at almost the same streamwise location as that induced by the three-dimensional roughness element.
Vibration of Spinning Cantilever Beams With an Attached Rigid Body Undergoing Bending-Bending-Torsional-Axial Motions
Authors: Cooley Christopher G. , Parker Robert G.
Published: October 2013

A linear model for the bending-bending-torsional-axial vibration of a spinning cantilever beam with a rigid body attached at its free end is derived using Hamilton's principle. The rotation axis is perpendicular to the beam (as for a helicopter blade, for example). The equations split into two uncoupled groups: coupled bending in the direction of the rotation axis with torsional motions and coupled bending in the plane of rotation with axial motions. Comparisons are made to existing models in the literature and some models are corrected. The practically important first case is examined in detail. The governing equations of motion are cast in a structured way using extended variables and extended operators. With this structure the equations represent a classical gyroscopic system and Galerkin discretization is readily applied where it is not for the original problem. The natural frequencies, vibration modes, stability, and bending-torsion coupling are investigated, including comparisons with past research.
Development and implementation of a remote audit tool for high dose rate (HDR) Ir‐192 brachytherapy using optically stimulated luminescence dosimetry
Authors: Casey Kevin E. , Alvarez Paola , Kry Stephen F. , Howell Rebecca M. , Lawyer Ann , Followill David
Published: October 2013

Purpose:

The aim of this work was to create a mailable phantom with measurement accuracy suitable for Radiological Physics Center (RPC) audits of high dose‐rate (HDR) brachytherapy sources at institutions participating in National Cancer Institute‐funded cooperative clinical trials. Optically stimulated luminescence dosimeters (OSLDs) were chosen as the dosimeter to be used with the phantom.

Methods:

The authors designed and built an 8 × 8 × 10 cm3 prototype phantom that had two slots capable of holding Al2O3:C OSLDs (nanoDots; Landauer, Glenwood, IL) and a single channel capable of accepting all 192Ir HDR brachytherapy sources in current clinical use in the United States. The authors irradiated the phantom with Nucletron and Varian 192Ir HDR sources in order to determine correction factors for linearity with dose and the combined effects of irradiation energy and phantom characteristics. The phantom was then sent to eight institutions which volunteered to perform trial remote audits.

Results:

The linearity correction factor waskL = (−9.43 × 10−5 × dose) + 1.009, where dose is in cGy, which differed from that determined by the RPC for the same batch of dosimeters using 60Co irradiation. Separate block correction factors were determined for current versions of both Nucletron and Varian 192Ir HDR sources and these vendor‐specific correction factors differed by almost 2.6%. For the Nucletron source, the correction factor was 1.026 [95% confidence interval (CI) = 1.023–1.028], and for the Varian source, it was 1.000 (95% CI = 0.995–1.005). Variations in lateral source positioning up to 0.8 mm and distal/proximal source positioning up to 10 mm had minimal effect on dose measurement accuracy. The overall dose measurement uncertainty of the system was estimated to be 2.4% and 2.5% for the Nucletron and Varian sources, respectively (95% CI). This uncertainty was sufficient to establish a ±5% acceptance criterion for source strength audits under a formal RPC audit program. Trial audits of four Nucletron sources and four Varian sources revealed an average RPC‐to‐institution dose ratio of 1.000 (standard deviation = 0.011).

Conclusions:

The authors have created an OSLD‐based192Ir HDR brachytherapy source remote audit tool which offers sufficient dose measurement accuracy to allow the RPC to establish a remote audit program with a ±5% acceptance criterion. The feasibility of the system has been demonstrated with eight trial audits to date.
On temporal integration versus frequency-based discrimination of direct-to-reverberant energy ratio
Authors: Larsen Erik , Iyer Nandini , Feng Albert , Lansing Charissa
Published: October 2013

The direct-to-reverberant (D/R) energy ratio is considered to be an important cue for sound source distance judgments (Zahorik, 2002; Bronkhorst, 2001). The current experiments investigated the processes that might be involved in D/R energy ratio discrimination. Two basic processes may be responsible: temporal integration and frequency domain changes. Temporal integration cues are available only if the on- and offset times of the stimulus are sufficiently rapid relative to the room reverberation time such that distinct direct and reverberant portions of the stimulus are perceived. Therefore, in the first experiment we compared JNDs for signals that either did or did not contain temporal integration cues by varying on- and offset time. We propose that the frequency-based method relies on the standard deviation of the spectral response in a reverberant room, which increases monotonically from 0 dB to 5.57 dB (Schroeder limit) as the D/R energy ratio decreases from approx. 20 dB to 0 dB. Outside this range, the standard deviation asymptotes and thus should not offer any cues for discrimination. Therefore, in the second experiment we compared JNDs for stimuli with D/R energy ratios inside and outside the range of 0–20 dB. The results from both these experiments will provide evidence for the processes of source distance coding based on the D/R energy ratio by the auditory system.
Discrimination of dynamic frequency sounds and a multichannel detector model
Authors: Rajendran Vivek , Krishnamurthy Ashok K. , Feth Lawrence L.
Published: October 2013

A virtual frequency (VF) glide signal refers to the frequency transition perceived in an amplitude-modulated two-tone complex. For example, when the amplitude of one tone increases with duration, while that of the other decreases, the listener hears a rising pitch. This virtual glide is easily distinguished from a linear frequency-modulated (FM) glide because of envelope fluctuations in the virtual glide. They can be rendered more difficult to discriminate by extracting the envelope from the VF glide and imposing it on the FM glide. Discrimination of common envelope VF and FM glides was studied through an adaptive 2Q, 2-AFC task. VF and FM glides (250 ms) were centered on 500-, 1000-, 2000-, and 4000-kHz. Frequency sweeps began at approximately 1/7 octave and were adjusted using the 2 up, 1 Down rule (Levitt, 1971). Center frequency roved over a range of approximately 1/2 octave for each interval. We show that a multichannel detector model (Durlach, 1986) operating on intensity weighted average of instantaneous frequency (IWAIF) values computed by a short-term, multichannel IWAIF model is able to predict listener performance in the common-envelope VF versus FM glide discrimination task. The noise variance required by the model is derived from measured FMDL data.
A speech compression/expansion method based on subband filtering of the signal envelope
Authors: Bjerkvik Aslak , Krokstad Asbjorn , Resch Barbara
Published: October 2013

Compression algorithms are used in hearing aids for hearing-impaired listeners with recruitment, due to these listeners’ loss of dynamic range. We propose a method for both compressing and expanding speech signals with the goal to improve speech intelligibility in reverberant conditions where the important rapid variations of the signal are inherently reduced. The method is based on dividing the envelope of the speech signal into two subbands with a division around modulation frequencies of 2 Hz, and compressing the signal based on the lower envelope subband, while expanding the signal based on the higher envelope subband. The sub-band division is accomplished by filtering the envelope of the signal and also by computing separate envelopes for each subband. A secondary goal is to develop low-delay algorithms. Various methods for calculating the envelope of the signal are evaluated, with a focus on the delay. a)Currently at KTH, Speech processing group, Stockholm, Sweden.
Perception of synthetic speech in quiet and in noise by adults with cochlear implants
Authors: Munson Benjamin , Nelson Peggy B.
Published: October 2013

Recent research has demonstrated that the ability of adults with cochlear implants (CI) to perceive speech in noise is highly variable. There are many potential reasons why this may be so, including poor signal/noise segregation, and poor perception of phonetic features in noise. We examined the CI listeners’ perception of four synthetic speech continua in quiet and in noise. In two continua, dynamic spectral information was manipulated (/ra/-/la/ and /wa/-/ja/); in one, static spectral information was manipulated (/i/-/u/); and in one, only temporal information was manipulated (/sei/-/stei/). These were presented to 12 listeners with CIs and 13 normal-hearing listeners in quiet and concurrent with speech-shaped noise, at a +10 dB SNR. Noise affected identification (endpoints, boundaries, and slopes) of CI listeners more than NH listeners. Significant group-by-SNR interactions were found for endpoint identification of the /ra/-/la/, /wa/-/ja/, and /sei/-/stei/ continua. CI listeners had significantly shallower identification slopes for the /ra/-/la/ continuum; this was exaggerated in the +10 dB SNR condition. In addition, CI listeners showed more /u/ percepts than the NH listeners in the /i/-/u/ continuum at +10 dB SNR. Results are discussed with respect to the relative vulnerability of temporal and spectral features to misperception in noisy conditions.
Target sound source extraction using spectral subtraction with a two-channel microphone array
Authors: Murakami Takahiro , Ishida Yoshihisa
Published: October 2013

A novel method for extracting a target sound source from the measurements of a two-channel microphone array is presented. In this paper, it is assumed that there is a single target sound source located directly in front of the array and a single noise source located in the other direction. The proposed method exploits the power spectrum of the difference signal between the signals observed at two microphones. Since the arrival times of the target sound are equal and those of the noise source are different, the difference signal contains only the noise signal. In the proposed method, the power spectrum of the difference signal is linearly modified on the assumption that the two microphones are located sufficiently close to each other, and then, the target source is extracted by using a spectral subtraction in which the power spectrum of the difference signal is subtracted from that of the observed signal. The proposed method requires neither delay estimation nor direction-of-arrival estimation, which are generally used for modification of the spectrum of the difference signal. Therefore, the proposed method is performed by a simple algebraic calculation.
Speech enhancement using parametric spectral subtraction combined with generalized sidelobe canceller
Authors: Cho Jaeyoun , Krishnamurthy Ashok
Published: October 2013

Speech enhancement is an important problem with applications in hearing aid design, speech recognition, speech coding, etc. Parametric spectral subtraction is a common method for speech enhancement when only a single channel of data is available. On the other hand, beamforming methods can be used when multiple channels of spatially separated data are available, such as from a microphone array. In previous work, we have shown that spectral subtraction combined with spatial averaging from multiple microphones leads to improvements in speech SNR and reduction of musical noise compared with either method used alone. In this talk, we extend the previous work to combine parametric spectral subtraction with adaptive beamforming, specifically the generalized sidelobe canceller. The proposed parametric spectral subtraction method determines the parameters adaptively so as to minimize speech distortion. In addition, it is shown that the major drawback of spectral subtraction, so-called musical noise, can be diminished by adaptive beamforming process. We show that the method leads to a reduction of musical noise and results in the enhanced speech having better quality and intelligibility.
Spoken digits recognition using DP matching combined with a subspace decomposition method
Authors: Kusakari Ken , Kiyoshi Kurihara , Murakami Takahiro , Ishida Yoshihisa
Published: October 2013

In this paper, we propose a method for spoken digits recognition using DP Matching combined with subspace decomposition that linearly separates into phonetic information from speaker information based on principle component analysis [M. Nishida and Y. Ariki, IEICE Trans. Japan J85-D-II, No. 4 (2002)]. This method allows for more robust speech recognition of less standard speech patterns. The use of the spectral envelope by LPC in speech recognition is unable to avoid errors in recognition due to the uncertainty of personalities, the dynamic variation of features, and so on. By using the subspace method, the proposed method eliminates these problems and enables good recognition results of less standard speech patterns. We use DP matching in recognizing, because it allows for more efficient pattern matching by normalizing the length of vowels. Simulation results show that the proposed method, using orthonormal projection to phonetic subspace with less speaker information, is superior to the conventional method using LPC spectra and DP Matching.
Listening for ambient bubbles in the marine boundary layer
Authors: Nystuen Jeffrey A.
Published: October 2013

Bubbles created by breaking waves and raindrop splashes are responsible for much of the high-frequency (500 Hz–50000 Hz) ambient sound in the ocean. Under high sea state and during heavy rainfall conditions clouds and layers of ambient bubbles in the marine boundary layer absorb sound from bubbles being newly created at the ocean surface. This absorption changes the shape of the ambient sound spectrum below the bubbly surface marine layer, allowing passive detection of the ambient bubbles. This change in the shape of the ambient sound spectrum is especially apparent in the situation of rainfall during high wind conditions, presumably because existing wind-generated turbulent from breaking waves is available to transport rainfall-generated bubbles downward. Estimates of vertically integrated ambient bubble populations can be made from the presumed frequency-dependent attenuation in the ambient sound spectrum. Ambient sound data from many months of deep ocean mooring measurements will be used to document this phenomenon. [Work sponsored by ONR Ocean Acoustics.]
Scaling laws for bubble acoustic radiation strength in whitecaps
Authors: Deane Grant B.
Published: October 2013

The past decade has seen significant advances in our understanding of open-ocean bubble plumes, including scaling laws for whitecap properties [W. K. Melville and P. Matusov, Nature (London) 417, 58–63 (2002)] and the physics of bubble creation [Garrett et al., J. Phys. Oceanogr. 30, 2163–2171 (2000), and G. B. Deane and M. D. Stokes, Nature (London) 418, 839–844 (2002)]. Despite this progress, we do not yet have a complete understanding of the relationship between noise radiated by whitecaps and the bubble creation processes occurring within the wave crest. Understanding this relationship is important: it would allow bubble-mediated gas transfer rates to be estimated from wind speed, for example, and provide a model for the Knudsen spectrum of underwater ambient noise. An important piece of this puzzle is the dependence of bubble acoustic radiation strength on bubble radius. We will present estimates of the scaling laws for this relationship based on open-ocean measurements of whitecap noise and laboratory measurements of bubble creation rates in plunging breakers. [Work supported by ONR and NSF.]
Evaluation of bubble–saturated subsurface sea layer by means of optoacoustics
Authors: Egerev Sergey V.
Published: October 2013

Laser sound generation has proved to be a useful tool for probing of various media. The pressure signal outgoing from the point of optoacoustic conversion provides information on the medium properties. The results are presented concerning optoacoustic conversion in the gas-containing bubbly subsurface sea layer. The sea surface is irradiated by a laser pulse. The subsequent acoustic signal, very susceptible to the subsurface gas content and propagating along the vertical axis z is recorded by a submerged hydrophone and interpreted. A model is developed to predict the features of signal, recorded during full–scale experiment conditions, making clear the formation of signal in nonuniform bubble–saturated subsurface layer, characterized by strong dispersion and additional acoustical absorption. The sound velocity increment Δc(z) along with the additional attenuation factor α(z) are parameters of a dispersion environment dependent upon the distribution of numerical bubble concentration n(R,z) upon their radii R at a current depth z. Laboratory test results of the phenomena along with the White Sea full-scale experimental results are presented. The equipment issues necessary for such measurements are discussed.
Epidemiologic methods in analysis of scientific issues
Authors: Erdreich Linda S.
Published: October 2013

Studies of human populations provide much of the information that is used to evaluate compensation cases for hearing loss, including rates of hearing loss by age, and dose–response relationships. The reference data used to make decisions regarding workman’s compensation is based on epidemiologic studies of cohorts of workers exposed to various noise levels. Epidemiology and its methods can be used in other ways in the courtroom; to assess the merits of a complaint, to support Daubert criteria, and to explain scientific issues to the trier of fact, generally a layperson. Using examples other than occupational noise induced hearing loss, these methods will be applied to respond to a complaint that hearing loss followed exposure to a sudden noise, a medication, or an occupational chemical, and thus was caused by said exposure. The standard criteria for assessing the weight of the evidence, and epidemiologic criteria for causality show the limits of such anecdotal data and incorporate quantitative and temporal issues. Reports of clusters of cases are also intuitively convincing to juries. Epidemiologic methods provide a scientific approach to assess whether rates of the outcome are indeed increased, and the extent to which increased rates provide evidence for causality.
Acoustic detectability of squid egg beds
Authors: Foote Kenneth G. , Hanlon Roger T. , Henry Annette E. , Hochstaedter Alfred , Kvitek Rikk , Sullivan Deidre , Yogozawa Yuko
Published: October 2013

Egg beds of the market squid (Loligo opalescens) on the bottom of Monterey Bay seem to have been detected by means of sidescan sonar at 420 kHz. Evidence for this is presented in the form of sidescan sonar images and egg-bed distribution maps from the same area, as prepared from camera surveys by scuba divers. The general detectability issue is also considered, with specific reference made to preliminary physical measurements performed on two egg capsules. [Work supported by Sea Grant.]
The influence of mesoscale eddies on shallow water acoustic propagation
Authors: DeFerrari Harry , Olson Donald
Published: October 2013

Acoustic propagation measurements in 150 m depth on the Florida escarpment observe the effects of the passage of a cyclonic eddy. As the stream core of the Florida Current meanders, the eddy is formed and propagates along the shelf edge. The sequence over a roughly a fortnight is as follows: ahead of the eddy, warm surface water and cold bottom water are swept onto the terrace forming a steep thermocline and corresponding strong downward refracting C(z). The gradient produce intense, focused RBR arrivals and the thermocline becomes a duct for internal waves to propagate shoreward. At first, the internal wave energy is minimal and propagation is stable and coherent. As the internal tides attempt to propagate on shelf, the sound speed field and the acoustic signals become increasingly variable. The variability reaches a crescendo as the 200 m long internal tide is blocked from propagating on to the narrower shelf and begins to break and overturn producing small-scale variability. As the eddy passes, nearly iso-thermal conditions are restored along with quiescent internal wave fields and reduced signal variability. Here, the effects are quantized with data from fixed-system acoustic and oceanographic measurements demonstrating that the mesoscale determines acoustic propagation conditions days in advance.
A normal-mode formula for the derivative of a waveguide pressure field with respect to an arbitrary three-dimensional sound speed perturbation
Authors: Thode Aaron
Published: October 2013

Semi-analytic expressions are derived for the first order derivative of a pressure field in a laterally homogeneous depth waveguide, with respect to an arbitrary three-dimensional refractive index perturbation in either the water column or ocean bottom. These expressions for the environmental derivative, derived using an adjoint method, require a three-dimensional spatial correlation between two Greens functions, weighted by an environmental parameter basis function, with the Greens functions expressed in terms of normal modes. When a particular set of orthogonal spatial basis functions is chosen, the three-dimensional spatial integral can be converted into a set of one-dimensional integrations over depth and azimuth. The use of the orthogonal basis permits environmental derivatives to be computed for any arbitrary sound-speed perturbation. To illustrate the formulas, a sensitivity study is presented that explores the impact of three-dimensional plane wave and cylindrical perturbations on the environmental derivative. Under certain circumstances it is found that perturbation components outside the vertical plane connecting the source and receiver have non-negligible effects on the pressure derivative. Potential applications of these formulas include benchmarking three-dimensional propagation codes, computing Cramer-Rao bounds for three-dimensional environmental parameter estimates, and potentially inverting for small three-dimensional refractive index distributions.
Optoacoustics for biomedical applications
Authors: Buma Takashi , Ye JingYong , Norris Theodore , Milas Susanne , Spisar Monica , Hollmann Kyle , O’Donnell Matthew , Hamilton James , Emelianov Stanislav , Balogh Lajos , Baker James
Published: October 2013

We are developing optical techniques to generate and receive ultrasound for various biomedical applications including high frequency 2D arrays, molecular imaging, and microfluidic devices. A 2D synthetic receive array uses a HeNe laser to probe the surface displacements of a thin reflective membrane. Images with near optimal resolution and wide fields of view have been produced at 10 to 50 MHz. A 75 MHz transmitting 2D array element relies on the thermoelastic effect. A 10 ns laser pulse is focused onto a 25 μm thick black polydimethylsiloxane (PDMS) film spin coated on a pure PDMS substrate. Our work in optoacoustic molecular imaging combines ultrafast lasers with high frequency ultrasound. When ultrafast laser pulses are focused into transparent media, laser induced optical breakdown (LIOB) produces acoustic emission and cavitation bubbles. A real-time acoustic technique has been developed to characterize LIOB in dendrimer nanocomposite (DNC) solutions. Lamb waves propagating in thin membranes have found widespread use in microfluidic devices. We use the thermoelastic effect as a noncontact method to generate continuous-wave Lamb waves in gold-coated membranes. We believe these results demonstrate the potential of optoacoustic methods for a broad range of applications in biomedical ultrasonics.
Ultrasound-aided high-resolution biophotonic imaging
Authors: Wang Lihong V.
Published: October 2013

We develop novel biophotonic imaging for early-cancer detection, a grand challenge in cancer research, using nonionizing electromagnetic and ultrasonic waves. Unlike ionizing x-ray radiation, nonionizing electromagnetic waves such as optical waves are safe for biomedical applications and reveal new contrast mechanisms and functional information. For example, our spectroscopic oblique-incidence reflectometry can detect skin cancers based on functional hemoglobin parameters and cell nuclear size with 95% accuracy. Unfortunately, electromagnetic waves in the nonionizing spectral region do not penetrate biological tissue in straight paths as do x-rays. Consequently, high-resolution tomography based on nonionizing electromagnetic waves alone, as demonstrated by our Mueller optical coherence tomography, is limited to superficial tissue imaging. Ultrasonic imaging, on the contrary, furnishes good imaging resolution but has poor contrast in early-stage tumors and has strong speckle artifacts as well. We developed ultrasound-mediated imaging modalities by combining electromagnetic and ultrasonic waves synergistically. The hybrid modalities yield speckle-free electromagnetic-contrast at ultrasonic resolution in relatively large biological tissue. In ultrasound-modulated (acousto)-optical tomography, a focused ultrasonic wave encodes diffuse laser light in scattering biological tissue. In photo-acoustic (thermo-acoustic) tomography, a low-energy laser (RF) pulse induces ultrasonic waves in biological tissue due to thermoelastic expansion.
Nonconventional approaches to ultrasonic assessment of skeletal system
Authors: Sarvazyan Armen
Published: October 2013

Conventional bone ultrasonometry is based on the transmission mode measurement of the linear acoustic parameters of bone (speed of sound and broadband attenuation). It is a well-established technique specifically for osteoporosis diagnostics though it is highly limited in its applications. It cannot be used for the assessment of the hip bone which is the most important area in characterization of the skeletal system and can hardly be used in pediatric applications, particularly in neonatology, for the assessment of newborns and premature and low-birth-weight infants skeletal systems, which became especially vital during the last few decades. There are several new ideas on acoustic assessment of the skeletal sites hardly accessible by the conventional bone ultrasonometry and on principles of the acoustic characterization of bone quality, fracture risk evaluation, and monitoring of therapeutic interventions. New approaches are based on the use of the ultrasound radiation pressure for the remote generation of acoustic waves in bones, on the use of various modes of guided acoustic waves having a propagation speed dependent on both the elasticity modulus and the bone thickness, on the use of geometrical dispersion of sound velocity for bone characterization, and the use of principles of nonlinear acoustic spectroscopy for remote bone testing. [Work supported by NIH.]
Adaptive linearized modeling and inversion for 3D tissue characterization
Authors: Ulker Karbeyaz Basak , Miller Eric L. , Cleveland Robin O. , Roy Ronald A.
Published: October 2013

Quantitative information regarding the acoustic velocity, absorption, and density of tissue given broadband ultrasonic (US) scattering data can enhance tissue characterization capabilities. Extracting quantitative information requires the use of a well-calibrated physical model directly within the processing algorithms. The computational size of most relevant 3D problems, with dimensions of tens to thousands of wavelengths on a side, render impractical the use of nonlinear inverse methods. Thus we must rely on linearized models obtained using the well-known first Born or first Rytov approximations. To extend the validity of these models and thereby improve their quantitative accuracy, we introduce an adaptive approach to the linearized inversion of US scattering data. We determine both the perturbations in the three acoustic parameters and the background properties around which the linearizion is performed. To make this adaptive re-linearization tractable for 3D US problems, we demonstrate a novel method for rapidly constructing the Born/Rytov kernels based on a new semi-analytic expression for the impulse response of the transducer. The approach is validated using simulated broadband US backscatter data as well as measurements in a tissue phantom. [Work supported in part by CenSSIS (NSF Award No. EEC-9986821) and NSF Award No. 0208548.]
Techniques in audio and acoustic measurement
Authors: Kite Thomas D.
Published: October 2013

Measurement of acoustic devices and spaces is commonly performed with time-delay spectrometry (TDS) or maximum length sequence (MLS) analysis. Both techniques allow an impulse response to be measured with a signal-to-noise ratio (SNR) that can be traded off against the measurement time. However, TDS suffers from long measurement times because of its linear sweep, while MLS suffers from the corruption of the impulse response by distortion. Recently a logarithmic sweep-based method has been devised which offers high SNR, short measurement times, and the ability to separate the linear impulse response from the impulse responses of distortion products. The applicability of these methods to audio and acoustic measurement will be compared.
Reflections on Elmer Hixson’s contributions to architectural acoustics
Authors: Calamia Paul T.
Published: October 2013

Although not often thought of in the context of architectural acoustics, many of Elmer Hixson’s research interests, for example in areas such as noise control, loudspeaker arrays, and acoustic sensors/measurements, are applicable to the design and analysis of concert halls and other performance spaces. In this presentation the author will discuss recent, current, and future directions of research in architectural acoustics, with emphasis on the contributions and influence of Elmer Hixson. Specific topics will include sound isolation and quiet HVAC design; the use of arrays in sound reinforcement systems; measurement and analysis of room-acoustics parameters; and predictive, three-dimensional computer modeling.
Piano acoustics—A review
Authors: Askenfelt Anders
Published: October 2013

The design of the piano as we know it today dates back to the second half of the 19th century. The history of studies of the acoustics of the piano begins during the same period. In this talk, known facts and unanswered questions about the acoustics of the piano are reviewed.
Active control of low-speed turbofan tonal noise
Authors: Sommerfeldt Scott D. , Remington Paul J.
Published: October 2013

Active noise control has been proposed as a technique for reducing the tonal noise radiated from turbofan engines. The sound field in the duct of a turbofan engine is characterized by acoustic modes, which exhibit both a radial and a circumferential spatial dependence. The dominant circumferential modes are determined by the relationship between the number of rotor and stator blades. Using these concepts, an active noise control system has been developed to measure and minimize the modes in the duct of a turbofan engine. By using multiple source and sensor locations, it has also been shown that it is possible to control multiple radial modes within the engine duct. Some of the issues associated with the design of the control system will be reviewed, and results obtained using the Active Noise Control Fan (ANCF) at NASA Glenn Research Center will be presented. [Work supported by NASA.]