bluuebunny/crossref_metadata_2025 huggingface dataset:
Applying the Cry of Pain Model as a predictor of deliberate self‐harm in an early‐stage adult male prison population
Authors: Slade Karen , Edelmann Robert , Worrall Marcia , Bray Diane
Published: October 2012

Purpose

Deliberate self‐harming behaviour is more prevalent within the prison environment than in community samples, with those in the first weeks of imprisonment at greatest risk. Research in this area has been largely atheoretical and a unifying model may improve the predictability of assessment and the development of intervention approaches. This study applied William and Pollock's (2001) Cry of Pain model as the theoretical process of deliberate self‐harm in the early stages of imprisonment.

Methods

A prospective study of new arrivals at an adult male prison. Participants (n = 181) completed questionnaires and it was hypothesized that the factors derived from the model (perceived stress, defeat, entrapment, and absence of rescue factors) would be predictive of future deliberate self‐harm. Prisoners with active psychosis and non‐English speakers were excluded. All participants were followed up for 4 months for instances of self‐harm. Eighteen participants engaged in self‐harm during this period.

Results

The Cry of Pain model was supported in the analysis. Hierarchical binary logistic regression confirmed that all features of the model were supported as predictive of future self‐harm in prison, even after controlling for previous self‐harm, depression, and hopelessness.

Conclusion

The Cry of Pain model is supported as a predictive model for deliberate self‐harm in prison. Suggestions are offered as to the impact on assessment and intervention directions in prison.
Clinical Characteristics, Mortality, Cardiac Hospitalization, and Ventricular Arrhythmias in Patients Undergoing CRT‐D Implantation: Results of the ACTION‐HF Study
Authors: BOTTO GIOVANNI LUCA , DICANDIA COSIMO DAMIANO , MANTICA MASSIMO , ROSA CONCETTO LA , D’ONOFRIO ANTONIO , BONGIORNI MARIA GRAZIA , MOLON GIULIO , VERLATO ROBERTO , VILLANI GIOVANNI QUINTO , SCACCIA ALBERTO , RACITI GIOVANNI , OCCHETTA ERALDO
Published: October 2012

CRT Patient Characteristics and Outcomes. Introduction: The characteristics and outcomes of patients who undergo cardiac resynchronization therapy (CRT) device implantation in current clinical practice may differ from those of reference trial populations. Study objectives were to assess 2‐year outcomes in a population implanted with a CRT plus defibrillator device in accordance with the standard of care and to evaluate any independent association between clinical variables and outcome.

Methods and Results:
A total of 406 patients enrolled at 35 centers in Italy were followed up prospectively for 2 years. All patient management decisions were left to the treating physician's discretion, in accordance with clinical practice. ACTION‐HF patients had a better baseline clinical status than patients enrolled in the COMPANION study: shorter HF history (1 vs 3.5 years, P < 0.01), less advanced NYHA functional class (III–IV: 73% vs 100%, P < 0.01), higher LVEF (26% vs 21%, P < 0.01), higher SBP (122 vs 112 mmHg, P < 0.01), and less diabetes (27% vs 41%, P < 0.01). This status was reflected in lower mortality (11.5% vs 26%) and a lower incidence of appropriate ICD shocks (12.1% vs 19.3%). AF history was an independent predictor of the combination of all‐cause mortality and cardiac‐cause hospitalization (HR: 3.31; P < 0.001). Recurrent or new atrial arrhythmias were independently associated with the development of ventricular arrhythmias (HR: 3.4; P < 0.001).

Conclusions

: This population appears clinically less compromised and had a lower incidence of adverse clinical outcomes than those of reference trials. However, we recorded a substantial burden of atrial arrhythmias, which was independently associated with a higher incidence of ventricular arrhythmias. (J Cardiovasc Electrophysiol, Vol. 24, pp. 173‐181, February 2013)
Oospore Wall Ornamentation in the Genus Tolypella (Charales, Charophyceae)
Authors: Urbaniak Jacek , Langangen Anders , van Raam Joop
Published: October 2012

The ultrastructural features of oospore wall ornamentation in the genus Tolypella were examined using scanning electron microscopy (SEM). The taxonomic relationships among several species were discussed on the basis of oospore ultrastructure and measurements. In the case of T. glomerata and T. nidifica, our results support the status of separate species. Close relationships and transitional forms may exist between T. nidifica and T. normaniana, and not only in oospore wall ornamentation. Oospores of T. hispanica exhibited the same distinct type of reticulate oospore wall as previously reported, but our results do not support the recognition of T. hispanica as a separate species. Ultrastructure of the oospore walls of T. prolifera and T. intricata was almost identical, suggesting that these species are closely related. We therefore reject previous suggestions that morphological characteristics of oospores as observed in SEM are sufficient for identification of individual species. Although significant differences were found among oospores in individual species of Tolypella, large variation among populations, and among individuals belonging to the same population, caused substantial overlap among species.
Environmental Optima for Seven Strains of Pseudochattonella (Dictyochophyceae, Heterokonta)
Authors: Skjelbred Birger , Edvardsen Bente , Andersen Tom
Published: October 2012

The ichthyotoxic flagellate Pseudochattonella has formed recurrent blooms in the North Sea, Skagerrak and Kattegat since 1998. Five strains of Pseudochattonella farcimen and two strains of P. verruculosa were examined in an assay comparing the light response of specific growth rates over a range of temperatures and salinities to get further knowledge on the autecology of members of this genus. Temperature optima were lower in P. farcimen (9°C–15°C) than in P. verruculosa (12°C–20°C). P. farcimen also showed a somewhat lower salinity optimum (18–26) than P. verruculosa (20–32). All strains showed light‐dependent growth responses reaching saturation between 18 and 52 μmol · photons · m−2 · s−1 at optimal temperature and salinity conditions. Compensation point estimates ranged from 4.2 to 15 μmol · photons · m−2 · s−1. Loss rates increased with temperature and were lowest at salinities close to optimal growth conditions. Blooms of P. farcimen have been recorded in nature under conditions more similar to those minimizing loss rates rather than those maximizing growth rates in our culture study.
High‐resolution colonic manometry accurately predicts colonic neuromuscular pathological phenotype in pediatric slow transit constipation
Authors: Giorgio V. , Borrelli O. , Smith V. V. , Rampling D. , Köglmeier J. , Shah N. , Thapar N. , Curry J. , Lindley K. J.
Published: October 2012

Background  Severe pediatric slow transit constipation (STC) is commonly due to intrinsic colonic neuromuscular disease. We sought to correlate neuromuscular histological phenotypes in pediatric STC with colonic manometric phenotypes using high‐resolution manometry (HRM). We tested the hypothesis that failure of motor quiescence (FQ) between bisacodyl‐induced high amplitude propagating sequences (HAPSs) might predict neuromuscular pathology.

Methods  Eighteen children (10 males, median age: 7.5 years) with refractory STC underwent stationary colonic HRM before segmental colonic resection. Six age‐matched constipated children with normal colonic transit served as controls. Colonic resection specimens underwent histopathological analysis. Conventional manometric parameters and area under the curve (AUC) during a 1‐min period following bisacodyl‐induced HAPSs [PBAUC1], as measure of FQ, were calculated.

Key Results  Numbers of postbisacodyl HAPSs in descending and sigmoid segments were lower in patients than controls (P < 0.01, respectively). Low amplitude propagating sequences (LAPSs) were common prebisacodyl in controls and rare in STC (P < 0.001), whereas postbisacodyl LAPS were more common in STC (P < 0.001). Postbisacodyl, both retrograde propagating contractions and bursts of contractions were present in STC patients only (P < 0.001 and P < 0.01). Postbisacodyl simultaneous pressurization was seen only in STC (P < 0.05 and P < 0.001, in descending and rectosigmoid segments). Histological abnormalities were present in 17/18. Fourteen were neurogenic, one neuro‐myogenic, and two myogenic. In segments with HAPS, PBAUC1 was predictive of colonic neuropathy using a cutoff of 205 mmHg.s‐1 (Sensitivity 100%, specificity 86%, PPV92%, NPV100%).

Conclusions & Inferences  PBAUC1 is increased in multiple colonic segments in neuropathic pediatric STC and constitutes a sensitive and specific biomarker of neuropathy.
Oral chronic graft‐versus‐host disease: current pathogenesis, therapy, and research
Authors: Mays JW , Fassil H , Edwards DA , Pavletic SZ , Bassim CW
Published: October 2012

Optimal management of complex autoimmune diseases requires a multidisciplinary medical team including dentists to care for lesions of the oral cavity. In this review, we discuss the presentation, prevalence, diagnosis, and treatment of oral manifestations in chronic graft‐versus‐host disease (cGVHD), which is a major late complication in patients treated by allogeneic hematopoietic stem cell transplantation. We assess current general knowledge of systemic and oral cGVHD and present general treatment recommendations based on literature review and our clinical experience. Additionally, we review areas where the understanding of oral cGVHD could be improved by further research and address tools with which to accomplish the long‐term goal of providing better health and quality of life to patients with cGVHD.
Expressions of C5a and Its Receptor CD88 After Spinal Cord Injury in C3‐deficient Mice
Authors: Guo Q. , Cheng J. , Zhang H. , Zhang J. , Su B. , Bian C. , Lin S.
Published: October 2012

The activation of complement system can aggravate the secondary injury after spinal cord injury (SCI). Our previous study indicates that the interception of complement activation by C3 deficiency can reduce the secondary injury and improve the regeneration and functional recovery after SCI. However, recently, it was reported that C5a which was generated during the complement activation pathways also had a protective effect on neurons, but whether it has the similar effect after SCI is unknown. To investigate the possibility and mechanism of the protective effect of C5a on neurons, it is necessary to study the expression profiles of C5a and its receptor CD88 after SCI and the influence on their expression when C3 was knocked out. By immunohistochemistry and Western blot, we found that in wild‐type (WT) mice, both the expression of C5a and its receptor CD88 increased significantly, and there were two peaks during their expression after SCI. However, in C3‐deficient mice, the expression of C5a still increased after SCI, although it was lower than that in WT group at every time points after SCI, and the expression of CD88 remained stable. Our study suggests that the expressions of C5a and CD88 can be inhibited in different degrees after SCI when the activation of complement system is blocked through C3 deficiency, which can reduce the secondary injury caused by C5a after SCI on one hand but deprive neurons of the possible protective effect from C5a on the other hand.
SUCROSE TRANSPORTER 5 supplies Arabidopsis embryos with biotin and affects triacylglycerol accumulation
Authors: Pommerrenig Benjamin , Popko Jennifer , Heilmann Mareike , Schulmeister Sylwia , Dietel Katharina , Schmitt Bianca , Stadler Ruth , Feussner Ivo , Sauer Norbert
Published: October 2012

The Arabidopsis SUC5 protein represents a classical sucrose/H+ symporter. Functional analyses previously revealed that SUC5 also transports biotin, an essential co‐factor for fatty acid synthesis. However, evidence for a dual role in transport of the structurally unrelated compounds sucrose and biotin in plants was lacking. Here we show that SUC5 localizes to the plasma membrane, and that the SUC5 gene is expressed in developing embryos, confirming the role of the SUC5 protein as substrate carrier across apoplastic barriers in seeds. We show that transport of biotin but not of sucrose across these barriers is impaired in suc5 mutant embryos. In addition, we show that SUC5 is essential for the delivery of biotin into the embryo of biotin biosynthesis‐defective mutants (bio1 and bio2). We compared embryo and seedling development as well as triacylglycerol accumulation and fatty acid composition in seeds of single mutants (suc5, bio1 or bio2), double mutants (suc5 bio1 and suc5 bio2) and wild‐type plants. Although suc5 mutants were like the wild‐type, bio1 and bio2 mutants showed developmental defects and reduced triacylglycerol contents. In suc5 bio1 and suc5 bio2 double mutants, developmental defects were severely increased and the triacylglycerol content was reduced to a greater extent in comparison to the single mutants. Supplementation with externally applied biotin helped to reduce symptoms in both single and double mutants, but the efficacy of supplementation was significantly lower in double than in single mutants, showing that transport of biotin into the embryo is lower in the absence of SUC5.
Concurrent Optimization of Computationally Learned Stylistic Form and Functional Goals
Authors: Tseng Ian , Cagan Jonathan , Kotovsky Kenneth
Published: October 2012

Great design often results from intelligently balancing tradeoffs and leveraging of synergies between multiple product goals. While the engineering design community has numerous tools for managing the interface between functional goals in products, there are currently no formalized methods to concurrently optimize stylistic form and functional requirements. This research develops a method to coordinate seemingly disparate but highly related goals of stylistic form and functional constraints in computational design. An artificial neural network (ANN) based machine learning system was developed to model surveyed consumer judgments of stylistic form quantitatively. Coupling this quantitative model of stylistic form with a genetic algorithm (GA) enables computers to concurrently account for multiple objectives in the domains of stylistic form and more traditional functional performance evaluation within the same quantitative framework. This coupling then opens the door for computers to automatically generate products that not only work well but also convey desired styles to consumers.
Assessment of the Relationships Among Design Methods, Design Activities, and Creativity
Authors: Chulvi Vicente , Sonseca Águeda , Mulet Elena , Chakrabarti Amaresh
Published: October 2012

This paper presents an experimental study that was conducted to compare the results obtained from using different design methods (brainstorming (BR), functional analysis (FA), and SCAMPER) in design processes. The objectives of this work are twofold. The first was to determine whether there are any differences in the length of time devoted to the different types of activities that are carried out in the design process, depending on the method that is employed; in other words, whether the design methods that are used make a difference in the profile of time spent across the design activities. The second objective was to analyze whether there is any kind of relationship between the time spent on design process activities and the degree of creativity in the solutions that are obtained. Creativity evaluation has been done by means of the degree of novelty and the level of resolution of the designed solutions using creative product semantic scale (CPSS) questionnaire. The results show that there are significant differences between the amounts of time devoted to activities related to understanding the problem and the typology of the design method, intuitive or logical, that are used. While the amount of time spent on analyzing the problem is very small in intuitive methods, such as brainstorming and SCAMPER (around 8–9% of the time), with logical methods like functional analysis practically half the time is devoted to analyzing the problem. Also, it has been found that the amount of time spent in each design phase has an influence on the results in terms of creativity, but results are not enough strong to define in which measure are they affected. This paper offers new data and results on the distinct benefits to be obtained from applying design methods.
Height distribution of atomic force microscopy images as a tool for atomic layer deposition characterization
Authors: Kolanek Krzysztof , Tallarida Massimo , Schmeisser Dieter
Published: October 2012

The authors propose the analysis of surface height histograms as a tool for the atomic layer deposition (ALD) growth characterization in the initial stage of the process. ALD of HfO2 on a Si(100)/SiO2 substrate was investigated in situ by ultra high vacuum atomic force microscope working in noncontact mode. The ALD cycles, made by using tetrakis-di-methyl-amido-Hf and H2O as precursors, were performed at 230 °C. After each ALD cycle, the relation between the film growth and the root mean square surface roughness was studied. Parameters equivalent to HfO2 layer thickness, coverage, and surface roughness of the substrate and deposited material can be calculated in the proposed routine.
Positron emission mammography (PEM): Effect of activity concentration, object size, and object contrast on phantom lesion detection
Authors: MacDonald Lawrence R. , Wang Carolyn L. , Eissa Marna , Haseley David , Kelly Mary M. , Liu Franklin , Parikh Jay R. , Beatty J. David , Rogers James V.
Published: October 2012

Purpose:

To characterize the relationship between lesion detection sensitivity and injected activity as a function of lesion size and contrast on the PEM (positron emission mammography) Flex Solo II scanner using phantom experiments.

Methods:

Phantom lesions (spheres 4, 8, 12, 16, and 20 mm diameter) were randomly located in uniform background. Sphere activity concentrations were 3 to 21 times the background activity concentration (BGc). BGc was a surrogate for injected activity; BGc ranged from 0.44–4.1 kBq/mL, corresponding to 46–400 MBq injections. Seven radiologists read 108 images containing zero, one, or two spheres. Readers used a 5‐point confidence scale to score the presence of spheres.

Results:

Sensitivity was 100% for lesions ≥12 mm under all conditions except for one 12 mm sphere with the lowest contrastand lowest BGc (60% sensitivity). Sensitivity was 100% for 8 mm spheres when either contrast or BGc was high, and 100% for 4 mm spheres only when both contrast and BGc were highest. Sphere contrast recovery coefficients (CRC) were 49%, 34%, 26%, 14%, and 2.8% for the largest to smallest spheres. Cumulative specificity was 98%.

Conclusions:

Phantom lesion detection sensitivity depends more on sphere size and contrast than on BGc. Detection sensitivity remained ≥90% for injected activities as low as 100 MBq, for lesions ≥8 mm. Low CRC in 4 mm objects results in moderate detection sensitivity even for 400 MBq injected activity, making it impractical to optimize injected activity for such lesions. Low CRC indicates that when lesions <8 mm are observed on PEM images they are highly tracer avid with greater potential of clinical significance. High specificity (98%) suggests that image statistical noise does not lead to false positive findings. These results apply to the 85 mm thick object used to obtain them; lesion detectability should be better (worse) for thinner (thicker) objects based on the reduced (increased) influence of photon attenuation.
The radiobiological P+ index for pretreatment plan assessment with emphasis on four‐dimensional radiotherapy modalities
Authors: Roland Teboh , Tryggestad Erik , Mavroidis Panayiotis , Hales Russell , Papanikolaou Nikos
Published: October 2012

Purpose:

Radiation treatment modalities will continue to emerge that promise better clinical outcomes albeit technologically challenging to implement. An important question facing the radiotherapy community then is the need to justify the added technological effort for the clinical return. Mobile tumor radiotherapy is a typical example, where 4D tumor tracking radiotherapy (4DTRT) has been proposed over the simpler conventional modality for better results. The modality choice per patient can depend on a wide variety of factors. In this work, we studied the complication‐free tumor control probability (P+) index, which combines the physical complexity of the treatment plan with the radiobiological characteristics of the clinical case at hand and therefore found to be useful in evaluating different treatment techniques and estimating the expected clinical effectiveness of different radiation modalities.

Methods:

4DCT volumes of 18 previously treated lung cancer patients with tumor motion and size ranging from 2 mm to 15 mm and from 4 cc to 462 cc, respectively, were used. For each patient, 4D treatment plans were generated to extract the 4D dose distributions, which were subsequently used with clinically derived radiobiological parameters to compute theP+ index per modality.

Results:

The authors observed, on average, a statistically significant increase inP+ of 3.4% ± 3.8% (p < 0.003) in favor of 4DTRT. There was high variability among the patients with a <0.5% up to 13.4% improvement in P+.

Conclusions:

The observed variability in the improvement of the clinical effectiveness suggests that the relative benefit of tracking should be evaluated on a per patient basis. Most importantly, this variability could be effectively captured in the computedP+. The index can thus be useful to discriminate and hence point out the need for a complex modality like 4DTRT over another. Besides tumor mobility, a wide range of other factors, e.g., size, location, fractionation, etc., can affect the relative benefits. Application of the P+ objective is a simple and effective way to combine these factors in the evaluation of a treatment plan.
Computational fluid dynamics simulation of sound propagation through a blade row
Authors: Zhao Lei , Qiao Weiyang , Ji Liang
Published: October 2012

The propagation of sound waves through a blade row is investigated numerically. A wave splitting method in a two-dimensional duct with arbitrary mean flow is presented, based on which pressure amplitude of different wave mode can be extracted at an axial plane. The propagation of sound wave through a flat plate blade row has been simulated by solving the unsteady Reynolds average Navier–Stokes equations (URANS). The transmission and reflection coefficients obtained by Computational Fluid Dynamics (CFD) are compared with semi-analytical results. It indicates that the low order URANS scheme will cause large errors if the sound pressure level is lower than −100 dB (with as reference pressure the product of density, main flow velocity, and speed of sound). The CFD code has sufficient precision when solving the interaction of sound wave and blade row providing the boundary reflections have no substantial influence. Finally, the effects of flow Mach number, blade thickness, and blade turning angle on sound propagation are studied.
Evaluating the effects of olivocochlear feedback on psychophysical measures of frequency selectivity
Authors: Jennings Skyler G. , Strickland Elizabeth A.
Published: October 2012

Frequency selectivity was evaluated under two conditions designed to assess the influence of a “precursor” stimulus on auditory filter bandwidths. The standard condition consisted of a short masker, immediately followed by a short signal. The precursor condition was identical except a 100-ms sinusoid at the signal frequency (i.e., the precursor) was presented before the masker. The standard and precursor conditions were compared for measurements of psychophysical tuning curves (PTCs), and notched noise tuning characteristics. Estimates of frequency selectivity were significantly broader in the precursor condition. In the second experiment, PTCs in the standard and precursor conditions were simulated to evaluate the influence of the precursor on PTC bandwidth. The model was designed to account for the influence of additivity of masking between the masker and precursor. Model simulations were able to qualitatively account for the perceptual data when outer hair cell gain of the model was reduced in the precursor condition. These findings suggest that the precursor may have reduced cochlear gain, in addition to producing additivity of masking. This reduction in gain may be mediated by the medial olivocochlear reflex.
Super-resolution imaging by resonant tunneling in anisotropic acoustic metamaterials
Authors: Liu Aiping , Zhou Xiaoming , Huang Guoliang , Hu Gengkai
Published: October 2012

The resonant tunneling effects that could result in complete transmission of evanescent waves are examined in acoustic metamaterials of anisotropic effective mass. The tunneling conditions are first derived for the metamaterials composed of classical mass-in-mass structures. It is found that the tunneling transmission occurs when the total length of metamaterials is an integral number of half-wavelengths of the periodic Bloch wave. Due to the local resonance of building units of metamaterials, the Bloch waves are spatially modulated within the periodic structures, leading to the resonant tunneling occurring in the low-frequency region. The metamaterial slab lens with anisotropic effective mass is designed by which the physics of resonant tunneling and the features for evanescent field manipulations are examined. The designed lens interacts with evanescent waves in the way of the propagating wavenumber weakly dependent on the spatial frequency of evanescent waves. Full-wave simulations validate the imaging performance of the proposed lens with the spatial resolution beyond the diffraction limit.
Homogenization theory for periodic distributions of elastic cylinders embedded in a viscous fluid
Authors: Reyes-Ayona Edgar , Torrent Daniel , Sánchez-Dehesa José
Published: October 2012

A multiple-scattering theory is applied to study the homogenization of clusters of elastic cylinders distributed in a isotropic lattice and embedded in a viscous fluid. Asymptotic relations are derived and employed to obtain analytical formulas for the effective parameters of homogenized clusters in which the underlying lattice has a low filling fraction. It is concluded that such clusters behave, in the low frequency limit, as an effective elastic medium. Particularly, it is found that the effective dynamical mass density follows the static estimate; i.e., the homogenization procedure does not recover the non-linear behavior obtained for the inviscid case. Moreover, the longitudinal and transversal sound speeds do not show any dependence on fluid viscosity. Numerical simulations performed for clusters made of brass cylinders embedded in glycerin support the reliability of the effective parameters resulting from the homogenization procedure reported here.
Design of an acoustic metamaterial lens using genetic algorithms
Authors: Li Dennis , Zigoneanu Lucian , Popa Bogdan-Ioan , Cummer Steven A.
Published: October 2012

The present work demonstrates a genetic algorithm approach to optimizing the effective material parameters of an acoustic metamaterial. The target device is an acoustic gradient index (GRIN) lens in air, which ideally possesses a maximized index of refraction, minimized frequency dependence of the material properties, and minimized acoustic impedance mismatch. Applying this algorithm results in complex designs with certain common features, and effective material properties that are better than those present in previous designs. After modifying the optimized unit cell designs to make them suitable for fabrication, a two-dimensional lens was built and experimentally tested. Its performance was in good agreement with simulations. Overall, the optimization approach was able to improve the refractive index but at the cost of increased frequency dependence. The optimal solutions found by the algorithm provide a numerical description of how the material parameters compete with one another and thus describes the level of performance achievable in the GRIN lens.
Electro-magnetically controlled acoustic metamaterials with adaptive properties
Authors: Malinovsky Vladimir S. , Donskoy Dimitri M.
Published: October 2012

A design of actively controlled metamaterial is proposed and discussed. The metamaterial consists of layers of electrically charged nano or micro particles exposed to external magnetic field. The particles are also attached to compliant layers in a way that the designed structure exhibits two resonances: mechanical spring-mass resonance and electro-magnetic cyclotron resonance. It is shown that if the cyclotron frequency is greater than the mechanical resonance frequency, the designed structure could be highly attenuative (40–60 dB) for vibration and sound waves in very broad frequency range even for wavelength much greater than the thickness of the metamaterial. The approach opens up wide range of opportunities for design of adaptively controlled acoustic metamaterials by controlling magnetic field and/or electrical charges.
Directional impulse response of a large cavity inside a sonic crystal
Authors: Spiousas Ignacio , Eguia Manuel C.
Published: October 2012

Both temporal and directional responses of a cavity inside a two-dimensional sonic crystal are investigated. The size of the cavity is large compared to the lattice parameter and the wavelength for the frequency range of interest. Hence, a hybrid method to compute the response is proposed, combining multiscattering theory for the calculation of the reflective properties of the sonic crystal with a modified ray-tracing algorithm for the sound propagation within the cavity. The response of this enclosure displays resonances for certain frequency bands that depend on the geometry of the lattice and the cavity. When a full band gap exists in the sonic crystal, rays cannot propagate through the medium and total reflection occurs for all incidence angles, leading to strong resonances with an isotropic intensity field inside the cavity. When only some propagation directions are forbidden, total reflection occurs for certain ranges of incidence angles, and resonances can also be elicited but with a highly anisotropic intensity field. The spectrum of resonances of the cavity is strongly affected by changes in the lattice geometry, suggesting that they can be tailored to some extent, a feature that can lead to potential applications in architectural acoustics.
Experimental demonstrations in audible frequency range of band gap tunability and negative refraction in two-dimensional sonic crystal
Authors: Pichard Hélène , Richoux Olivier , Groby Jean-Philippe
Published: October 2012

The propagation of audible acoustic waves in two-dimensional square lattice tunable sonic crystals (SC) made of square cross-section infinitely rigid rods embedded in air is investigated experimentally. The band structure is calculated with the plane wave expansion (PWE) method and compared with experimental measurements carried out on a finite extend structure of 200 cm width, 70 cm depth and 15 cm height. The structure is made of square inclusions of 5 cm side with a periodicity of L = 7.5 cm placed inbetween two rigid plates. The existence of tunable complete band gaps in the audible frequency range is demonstrated experimentally by rotating the scatterers around their vertical axis. Negative refraction is then analyzed by use of the anisotropy of the equi-frequency surface (EFS) in the first band and of a finite difference time domain (FDTD) method. Experimental results finally show negative refraction in the audible frequency range.
Effects of the local resonance on the wave propagation in periodic frame structures: Generalized Newtonian mechanics
Authors: Chesnais Céline , Boutin Claude , Hans Stéphane
Published: October 2012

This work is devoted to the study of the wave propagation in infinite two-dimensional structures made up of the periodic repetition of frames. Such materials are highly anisotropic and, because of lack of bracing, can present a large contrast between the shear and compression deformabilities. Moreover, when the thickness to length ratio of the frame elements is small, these elements can resonate in bending at low frequencies when compressional waves propagate in the structure. The frame size being small compared to the wavelength of the compressional waves, the homogenization method of periodic discrete media is extended to situations with local resonance, and it is applied to identify the macroscopic behavior at the leading order. In particular, the local resonance in bending leads to an effective mass different from the real mass and to the generalization of the Newtonian mechanics at the macroscopic scale. Consequently, compressional waves become dispersive and frequency bandgaps occur. The physical origin of these phenomena at the microscopic scale is also presented. Finally, a method is proposed for the design of such materials.
Effects of periodicity perturbations on the transmission by underwater phononic crystals
Authors: Zong K. , Franklin H. , Lenoir O. , Predoi M. V.
Published: October 2012

The effects of periodicity perturbations in underwater phononic crystal layers composed of noninterpenetrating rows of identical shells are investigated. The results for one row are obtained by using a multiple scattering method between shells. Then, taking into account the multiple reflections and transmissions between two adjacent rows, a Debye series method is used to calculate the reflection and transmission coefficients by a finite number of rows. The paper focuses on three kinds of perturbations: (i) variation of the inner radius of shells from row to row, (ii) increase in the spacing from row to row and of the number of rows, and (iii) substitution of simple steel rows by steel-polyethylene bilayers. It is shown by studying the transmission coefficient that the case (i) permits the insertion of narrow pass bands in the stop band while the two other cases (ii) and (iii) widen the stop band. The study intends to model simple underwater acoustic filters.
Anomalous wave propagation in a one-dimensional acoustic metamaterial having simultaneously negative mass density and Young’s modulus
Authors: Huang H. H. , Sun C. T.
Published: October 2012

A mechanical model representing an acoustic metamaterial that exhibits simultaneously negative mass density and negative Young’s modulus was proposed. Wave propagation was studied in the frequency range of double negativity. In view of positive energy flow, it was found that the phase velocity in this range is negative. This phenomenon was also observed using transient wave propagation finite-element analyses of a transient sinusoidal wave and a transient wave packet. In contrast to wave propagation in the region of positive mass and modulus, the peculiar backward wave motion in the region of double negativity was clearly displayed.
Optimizing imperfect cloaks to perfection
Authors: Cai Liang-Wu
Published: October 2012

Transformation optics has been an essential tool for designing cloaking devices for electromagnetic and acoustic waves. All these designs have one requirement in common: material singularity. At the interface between the cloak and the cloaked region, some material properties have to approach infinity, while some others approach zero. This paper attempts to answer a central question in physically realizing such cloaks: is material singularity a requirement for perfect cloaking? This paper demonstrates that, through optimization, perfect cloaking can be achieved using a layered cloak construction without material singularity. Two examples are used for this demonstration. In one example, the initial design is based on the Cummer–Schurig prescription for acoustic cloaking that requires mass-anisotropic material. Another example uses the two isotropic layers to achieve the equivalent mass-anisotropy for each anisotropic layer. During the optimization processes, only material properties of cloaks’ constituent layers are adjusted while the geometries remain unchanged. In both examples, the normalized total scattering cross section can be reduced to 0.002 (0.2%) or lower in numerical computations. The capabilities and other characteristics of the optimization in other tasks such as cloaking penetrable objects and isolating strong resonance in such objects are also explored.
Trans-dimensional matched-field geoacoustic inversion with hierarchical error models and interacting Markov chains
Authors: Dettmer Jan , Dosso Stan E.
Published: October 2012

This paper develops a trans-dimensional approach to matched-field geoacoustic inversion, including interacting Markov chains to improve efficiency and an autoregressive model to account for correlated errors. The trans-dimensional approach and hierarchical seabed model allows inversion without assuming any particular parametrization by relaxing model specification to a range of plausible seabed models (e.g., in this case, the number of sediment layers is an unknown parameter). Data errors are addressed by sampling statistical error-distribution parameters, including correlated errors (covariance), by applying a hierarchical autoregressive error model. The well-known difficulty of low acceptance rates for trans-dimensional jumps is addressed with interacting Markov chains, resulting in a substantial increase in efficiency. The trans-dimensional seabed model and the hierarchical error model relax the degree of prior assumptions required in the inversion, resulting in substantially improved (more realistic) uncertainty estimates and a more automated algorithm. In particular, the approach gives seabed parameter uncertainty estimates that account for uncertainty due to prior model choice (layering and data error statistics). The approach is applied to data measured on a vertical array in the Mediterranean Sea.
Opposing and following vocal responses to pitch-shifted auditory feedback: Evidence for different mechanisms of voice pitch control
Authors: Behroozmand Roozbeh , Korzyukov Oleg , Sattler Lindsey , Larson Charles R.
Published: October 2012

The present study describes a technique for analysis of vocal responses to auditory feedback pitch perturbations in which individual trials are first sorted according to response direction and then separately averaged in groups of upward or downward responses. In experiment 1, the stimulus direction was predictable (all upward) but magnitude was randomized between +100, +200, or +500 cents (unpredictable). Results showed that pitch-shift stimuli (PSS) of +100 and +200 cents elicited significantly larger opposing (compensatory) responses than +500 cent stimuli, but no such effect was observed for “following” responses. In experiment 2, subjects were tested in three blocks of trials where for the first two, PSS magnitude and direction were predictable (block 1+100 and block 2–100 cents), and in block 3, the magnitude was predictable (±100 cents) but direction was randomized (upward or downward). Results showed there were slightly more opposing than following responses for predictable PSS direction, but randomized directions led to significantly more opposing than following responses. Results suggest that predictability of stimulus direction and magnitude can modulate vocal responses to feedback pitch perturbations. The function and causes of the opposing and following responses are unknown, but there may be two different neural mechanisms involved in their production.
Imaging small three-dimensional elastic inclusions by an enhanced multiple signal classification method
Authors: Song Rencheng , Chen Xudong , Zhong Yu
Published: October 2012

In this paper, an enhanced multiple signal classification (MUSIC) algorithm is introduced to retrieve small three-dimensional elastic inclusions. First, the multistatic response (MSR) matrix is built by two different ways depending on considering the multiple scattering effect or not. The eigenvalue structure of the MSR matrix is analyzed to identify the degenerate case of inclusions. Second, the pseudo-spectrum function is built with an optimal test direction on each node, where a balancing technique is employed to ensure the numerical stability. Benefitting from this MUSIC indicator, the degenerate inclusions can be located with a good performance against noise. Numerical simulations show the proposed method has wider applicability, better resolution, and more robust in the presence of noise than the standard MUSIC methods.
Two-dimensional acoustic scattering, conformal mapping, and the Rayleigh hypothesis
Authors: Martin P. A.
Published: October 2012

Methods for solving two-dimensional scattering problems using conformal mappings are investigated. It is shown that their convergence relies on a mapped form of the Rayleigh hypothesis. It is concluded that methods based on conformal mappings offer no advantages over established methods in which the scattered field is expanded as a series of circular-cylindrical outgoing wavefunctions.
Better-ear glimpsing efficiency with symmetrically-placed interfering talkers
Authors: Brungart Douglas S. , Iyer Nandini
Published: October 2012

In listening tasks where a target speech signal is spatially separated from a masking voice, listeners can often gain a substantial advantage in performance by attending to the ear with the better signal-to-noise ratio (SNR). However, this better-ear strategy becomes much more complicated when a target talker located in front of the listener is masked by interfering talkers positioned at symmetric locations to the left and right of the target. When this happens, there are no long-term SNR advantages at either ear and the only binaural SNR advantages available are the result of complicated better-ear glimpses that vary as a function of frequency and rapidly switch back and forth between the two ears according to the natural fluctuations in the relative levels of the two masking voices. In this study, a signal processing technique was used to take the better-ear glimpses that would ordinarily be randomly distributed across the two ears in a binaural speech signal and move them all into the same ear. This resulted in a monaural signal that contained all the information available to an ideal listener using an optimal binaural glimpsing strategy. Speech intelligibility was measured with these optimized monaural stimuli and compared to performance with unprocessed binaural speech stimuli. Performance was similar in these two conditions, suggesting that listeners with normal hearing are able to efficiently extract information from better-ear glimpses that fluctuate rapidly across frequency and across the two ears.
A psychoacoustic method for studying the necessary and sufficient perceptual cues of American English fricative consonants in noise
Authors: Li Feipeng , Trevino Andrea , Menon Anjali , Allen Jont B.
Published: October 2012

In a previous study on plosives, the 3-Dimensional Deep Search (3DDS) method for the exploration of the necessary and sufficient cues for speech perception was introduced (Li et al., (2010). J. Acoust. Soc. Am. 127(4), 2599–2610). Here, this method is used to isolate the spectral cue regions for perception of the American English fricatives /∫, ʒ, s, z, f, v, θ, ð/ in time, frequency, and intensity. The fricatives are analyzed in the context of consonant-vowel utterances, using the vowel /ɑ/. The necessary cues were found to be contained in the frication noise for /∫, ʒ, s, z, f, v/. 3DDS analysis isolated the cue regions of /s, z/ between 3.6 and 8 [kHz] and /∫, ʒ/ between 1.4 and 4.2 [kHz]. Some utterances were found to contain acoustic components that were unnecessary for correct perception, but caused listeners to hear non-target consonants when the primary cue region was removed; such acoustic components are labeled “conflicting cue regions.” The amplitude modulation of the high-frequency frication region by the fundamental F0 was found to be a sufficient cue for voicing. Overall, the 3DDS method allows one to analyze the effects of natural speech components without initial assumptions about where perceptual cues lie in time-frequency space or which elements of production they correspond to.
Transducer figure of merit (L)
Authors: Butler John L.
Published: October 2012

An alternative formula for determining the volume-referenced, projector-transducer figure of merit, FOMv, is developed allowing an evaluation based on well known parameters that may be readily calculated or measured. This formula is also reduced to the special case of piezoelectric or magnetostrictive materials, allowing a FOMv comparison of transducer materials in addition to an evaluation of specific transducer designs. Sample results are given for transducer materials alone and a PZT-8 driven modal projector transducer operated in the monopole mode.
Dynamic response of an array of flexural plates in acoustic medium
Authors: Park Kwan Kyu , Khuri-Yakub Brutus T.
Published: October 2012

The dynamic response of a transducer array made up of circular flexural plates in immersion is analytically calculated. The calculation method includes three steps: (1) the calculation of parallel resonant frequency and the velocity profile of each plate, (2) the calculation of mutual acoustic impedance between the plates, and (3) the calculation of velocity response, including the mechanical and acoustic impedance. The calculation method is validated by both finite element analysis and measurement results of a fabricated capacitive micromachined ultrasonic transducer. Based on the calculated velocity, the near-field pressure and the near-to-far field radiation patterns are presented. The flexural plate array in immersion displays two modes of operation. At low frequency, the mode shape of the transducer array is similar to that of a suspended plate and, at certain frequencies, two groups of plates move in opposite phase, which results in the cancellation of the average velocity. At high frequency, the mode shape is similar to that of a piston transducer; however, the near-field pressure distribution is similar to that of a resilient disk.
Evidence for language transfer leading to a perceptual advantage for non-native listeners
Authors: Chang Charles B. , Mishler Alan
Published: October 2012

Phonological transfer from the native language is a common problem for non-native speakers that has repeatedly been shown to result in perceptual deficits vis-à-vis native speakers. It was hypothesized, however, that transfer could help, rather than hurt, if it resulted in a beneficial bias. Due to differences in pronunciation norms between Korean and English, Koreans in the U.S. were predicted to be better than Americans at perceiving unreleased stops—not only in their native language (Korean) but also in their non-native language (English). In three experiments, Koreans were found to be significantly more accurate than Americans at identifying unreleased stops in Korean, at identifying unreleased stops in English, and at discriminating between the presence and absence of an unreleased stop in English. Taken together, these results suggest that cross-linguistic transfer is capable of boosting speech perception by non-natives beyond native levels.