bluuebunny/crossref_metadata_2025 huggingface dataset:
The Motivations of Palestinian Suicide Bombers in the Second Intifada (2000 to 2005)
Authors: Araj Bader
Published: August 2012

Malgré 16 ans d'histoire (1993‐2009), les recherches sur les kamikazes palestiniens qui se fondent sur des données de base demeurent rares, et aucune étude précédente faisant une analyse d’échantillons représentatifs de cas n'existe. Basé sur des entretiens menés par l'auteur en 2006 avec des proches et amis de 42 kamikazes palestiniens sélectionnés aléatoirement et représentant environ un quart des kamikazes palestiniens de la deuxième intifada (2000‐2005), cet article conclut que les motivations de ces bombes humaines sont généralement complexes. Par ordre décroissant, les motivations comprennent (1) un désir de vengeance contre les forces israéliennes et leurs mesures répressives excessives, (2) l'inspiration religieuse et (3) le désir de libération de la patrie.
Early Cenozoic Mega Thrusting in the Qiangtang Block of the Northern Tibetan Plateau
Authors: Zhenhan WU , Peisheng YE , BAROSH Patrick J. , Daogong HU , Lu LU , Yaoling ZHANG
Published: August 2012

Recent mapping and seismic survey reveal that intensive compression during the Early Cenozoic in the Qiangtang block of the central Tibetan Plateau formed an extensive complex of thrust sheets that moved relatively southward along several generally north‐dipping great thrust systems. Those at the borders of the ∼450 km wide block show it overrides the Lhasa block to the south and is overridden by the Hohxil‐Bayanhar block to the north. The systems are mostly thin‐skinned imbricate thrusts with associated folding. The thrust sheets are chiefly floored by Jurassic limestone that apparently slid over Triassic sandstone and shale, which is locally included, and ramped upward and over Paleocene‐Eocene red‐beds. Some central thrusts scooped deeper and carried up Paleozoic metamorphic rock, Permian carbonate and granite to form a central uplift that divides the Qiangtang block into two parts. These systems and their associated structures are unconformably overlain by little deformed Late Eocene‐Oligocene volcanic rock or capped by Miocene lake beds. A thrust system in the northern part of the block, as well as one in the northern part of the adjacent Lhasa block, dip to the south and appear to be due to secondary adjustments within the thrust sheets.

The relative southward displacement across this Early Cenozoic mega thrust system is in excess of 150 km in the Qiangtang block, and the average southward slip‐rate of the southern Qiangtang thrusts ranged from 5.6 mm to 7.4 mm/a during the Late Eocene‐Oligocene. This Early Cenozoic thrusting ended before the Early Miocene and was followed by Late Cenozoic crustal extension and strike‐slip faulting within the Qiangtang block. The revelation and understanding of these thrust systems are very important for the evaluation of the petroleum resources of the region.
Simulation for the Controlling Factors of Structural Deformation in the Southern Margin of the Junggar Basin
Authors: Fusheng YU , Xiaojian LI , Dinghua LI , Zicheng FENG , Xueliang LI
Published: August 2012

According to the differences of structural deformation characteristics, the southern margin of the Junggar basin can be divided into two segments from east to west. Arcuate thrust‐and‐fold belts that protrude to the north are developed in the eastern segment. There are three rows of en echelon thrust‐and‐fold belts in the western segment. Thrust and fold structures of basement‐involved styles are developed in the first row, and décollement fold structures are formed from the second row to the third row. In order to study the factors controlling the deformation of structures, sand‐box experiments have been devised to simulate the evolution of plane and profile deformation. The planar simulation results indicate that the orthogonal compression coming from Bogeda Mountain and the oblique compression with an angle of 75° between the stress and the boundary originating from North Tianshan were responsible for the deformation differences between the eastern part and the western part. The Miquan‐Ürümqi fault in the basement is the pre‐existing condition for generating fragments from east to west. The profile simulation results show that the main factors controlling the deformation in the eastern part are related to the décollement of Jurassic coal beds alone, while those controlling the deformation in the western segment are related to both the Jurassic coal beds and the Eogene clay beds. The total amount of shortening from the Yaomoshan anticline to the Gumudi anticline in the eastern part is ∼19.57 km as estimated from the simulation results, and the shortening rate is about 36.46%; that from the Qingshuihe anticline to the Anjihai anticline in the western part is ∼22.01 km as estimated by the simulation results, with a shortening rate of about 32.48%. These estimated values obtained from the model results are very close to the values calculated by means of the balanced cross section.
Crustal Structure across the Northwestern Margin of South China Sea: Evidence for Magma‐poor Rifting from a Wide‐angle Seismic Profile
Authors: Weiwei DING , SCHNABEL Michael , FRANKE Dieter , Aiguo RUAN , Zhenli WU
Published: August 2012

We present results from a 484 km wide‐angle seismic profile acquired in the northwest part of the South China Sea (SCS) during OBS2006 cruise. The line that runs along a previously acquired multi‐channel seismic line (SO49–18) crosses the continental slope of the northern margin, the Northwest Subbasin (NWSB) of the South China Sea, the Zhongsha Massif and partly the oceanic basin of the South China Sea. Seismic sections recorded on 13 ocean‐bottom seismometers were used to identify refracted phases from the crustal layer and also reflected phases from the crust‐mantle boundary (Moho). Inversion of the traveltimes using a simple start model reveals crustal images in the study area. The velocity model shows that crustal thickness below the continental slope is between 14 and 23 km. The continental part of the line is characterized by gentle landward mantle uplift and an abrupt oceanward one. The velocities in the lower crust do not exceed 6.9 km/s. With the new data we can exclude a high‐velocity lower crustal body (velocities above 7.0 km/s) at the location of the line. We conclude that this part of the South China Sea margin developed by a magma‐poor rifting. Both, the NWSB and the Southwest Sub‐basin (SWSB) reveal velocities typical for oceanic crust with crustal thickness between 5 and 7 km. The Zhongsha Massif in between is extremely stretched with only 6–10 km continental crust left. Crustal velocity is below 6.5 km/s; possibly indicating the absence of the lower crust. Multi‐channel seismic profile shows that the Yitongansha Uplift in the slope area and the Zhongsha Massif are only mildly deformed. We considered them as rigid continent blocks which acted as rift shoulders of the main rift subsequently resulting in the formation of the Northwest Sub‐basin. The extension was mainly accommodated by a ductile lower crustal flows, which might have been extremely attenuated and flow into the oceanic basin during the spreading stage. We compared the crustal structures along the northern margin and found an east‐west thicken trend of the crust below the continent slope. This might be contributed by the east‐west sea‐floor spreading along the continental margin.
Magma Origin and Evolution of Tengchong Cenozoic Volcanic Rocks from West Yunnan, China: Evidence from Whole Rock Geochemistry and Nd‐Sr‐Pb Isotopes
Authors: Dapeng LI , Zhaohua LUO , Jiaqi LIU , Yuelong CHEN , Ye JIN
Published: August 2012

Tengchong Cenozoic volcanics that have record key information on the tectonic evolution and mantle features of the southeast margin of the Tibetan Plateau are of great importance because of its unique eruption history spanning the entire Quaternary period. Magma origin and evolution of Tengchong Cenozoic volcanic rocks were studied on the basis of Nd‐Sr‐Pb isotope and major and trace element data from different eruptions in the Ma'anshan area. Different samples within one eruption show relative identical lithologies, chemical and isotopic compositions. However, the geochemical features for the five eruptions are distinct from each other. These volcanic rocks show low Mg# values (<45), moderate to high fractionation of LREEs and HREEs, and enrichment of Pb and Ba and depletion of Nb. Tengchong Cenozoic volcanic rocks were derived from an enriched mantle based on Nd‐Sr‐Pb isotopic studies. And lines of evidence show that crustal contamination should be involved before the eruption of different periods of Tengchong Cenozoic volcanic rocks. Older subducted components may be responsible for adakite recycling at various stages of evolution, which results in the origin of the enriched mantle source magma accounting for the isotopic features of Tengchong Cenozoic volcanic rocks. Segregated primitive magma pulsating injected into magma chamber, fractional crystallized and contaminated with crust component. Finally, magmas with distinct chemical and isotopic compositions for each eruption formed. The extension of the northeast segment of the Yingjiang tectonic belt triggered the pulsating eruption of the Cenozoic volcanics in the Tengchong area.
Carbon Fluxes and Sinks: the Consumption of Atmospheric and Soil CO2 by Carbonate Rock Dissolution
Authors: Jianhua CAO , Daoxian YUAN , GROVES Chris , Fen HUANG , Hui YANG , Qian LU
Published: August 2012

Carbonate rock outcrops cover 9%–16% of the continental area and are the principal source of the dissolved inorganic carbon (DIC) transferred by rivers to the oceans, a consequence their dissolution. Current estimations suggest that the flux falls between 0.1–0.6 PgC/a. Taking the intermediate value (0.3 PgC/a), it is equal to 18% of current estimates of the terrestrial vegetation net carbon sink and 38% of the soil carbon sink. In China, the carbon flux from carbonate rock dissolution is estimated to be 0.016 PgC/a, which accounts for 21%, 87.5%–150% and 2.3 times of the forest, shrub and grassland net carbon sinks respectively, as well as 23%–40% of the soil carbon sink flux. Carbonate dissolution is sensitive to environmental and climatic changes, the rate being closely correlated with precipitation, temperature, also with soil and vegetation cover. HCO–3 in the water is affected by hydrophyte photosynthesis, resulting in part of the HCO–3 being converted into DOC and POC, which may enhance the potential of carbon sequestration by carbonate rock dissolution. The possible turnover time of this carbon is roughly equal to that of the sea water cycle (2000a). The uptake of atmospheric/soil CO2 by carbonate rock dissolution thus plays an important role in the global carbon cycle, being one of the most important sinks. A major research need is to better evaluate the net effect of this sink in comparison to an oceanic source from carbonate mineral precipitation.
Practice change in community pharmacy: using change-management principles when implementing a pharmacy asthma management service in NSW, Australia
Authors: Feletto Eleonora , Lui Grace Wan Ying , Armour Carol , Saini Bandana
Published: August 2012

Objective

This study aimed to investigate the application of a research-based change-management tool, the Pharmacy Change Readiness Wheel (PCRW), in practice, and the impact it had on the implementation of an asthma service (Pharmacy Asthma Management Service or PAMS).

Methods

All pharmacists implementing the PAMS in the state of New South Wales, Australia, were provided training using a custom-designed module explaining change readiness as it applied to the PAMS. This training and a self-administered PCRW checklist were completed before PAMS implementation. Following PAMS service delivery, semi-structured phone interviews were conducted with the pharmacists and any additional staff involved regarding their experiences of change management. Interviews were transcribed verbatim and content analysed.

Key findings

Thirty seven of the forty five pharmacies who delivered PAMS returned the PCRW checklist (82% response rate) and participants from 29 pharmacies were interviewed (29 pharmacists and six additional staff). Perception of readiness for change before service delivery was remarkably high. From the interviews conducted after service delivery it was evident that systematic management of the practice change using theoretical concepts had not really been undertaken and that many challenges were faced in the implementation of practice change (PAMS). The results of the content analysis from the interviews revealed that factors external or internal to the pharmacy or those related to the individual pharmacist could affect implementation of practice change.

Conclusion

Change is not as straightforward as it may appear and is a multi-step process over time. Pharmacists were unaware of this. A change-management framework should be applied to specific services with enough flexibility so that pharmacists can individualise them for their pharmacies.
Impacts of infancy rapid weight gain on 5‐year childhood overweight development vary by age and sex in China
Authors: Min J. , Li J. , Li Z. , Wang Y.
Published: August 2012

Objectives

To investigate the critical period for overweight development during early childhood by examining growth trajectory and related sex differences.

Methods

Using piecewise linear mixed models and logistic regression, we examined the effect of growth trajectory at different periods on overweight at age 4–5 by sex among 136 971 regularly followed children (mean: 12.2 times) during 2000–2005 in south China.

Results

The high‐body mass index (BMI) group (>top tertile of BMI Z score at age of 4–5 years) had faster growth rates of BMI, BMI Z score, weight and height than the low‐BMI group in the first 3 months of life. Boys were more likely to be overweight [odds ratio (OR) = 2.0, 95% confidence interval: 1.5–2.7] than girls; the male high‐BMI group had higher growth rates during the first 3 months than girls with high‐BMI, independently of environmental factors. Those fast grown (in the upper tertile of growth rates in BMI and BMI Z score) in periods 0–3 months had relatively higher OR of at risk of overweight at age of 4–5 years than those in other periods.

Conclusions

Overweight risk develops during the first 3 months of life. Boys have an earlier peak in growth than girls, which may help explain why overweight is more prevalent in boys in China.
The role of Cl− in the regulation of ion and liquid transport in the intact alveolus during β‐adrenergic stimulation
Authors: Alexandrou Dionysios , Walters Dafydd V.
Published: August 2012

New findings

What is the central question of this study?

The co‐ordinated regulation of ion transport across the pulmonary epithelium determines the volume of the thin liquid layer lining the normal lung. However, the integrated homeostasis of the liquid transport physiology of the intact alveolus remains elusive.

What is the main finding and its importance?

Using a whole‐lung preparation, we explored the mechanism of the β‐agonist‐mediated upregulation of Na+ and alveolar liquid clearance, leading to resolution of pulmonary oedema. We demonstated the functional presence of secretory rather than absorptive Cl− channels, which implies that this upregulation is mediated via a direct effect on Na+ conductance and not through transepithelial Cl− absorption and an increased driving force for Na+.

The epithelium of the developing lung displays an evolving liquid transport phenotype, in which Cl− secretion during fetal life is rapidly switched to Na+ absorption perinatally. However, the mechanisms underlying the homeostasis of the thin layer of liquid lining the postnatal pulmonary epithelium remain elusive. In particular, it remains unclear whether the stimulated clearance of excess alveolar liquid is mediated via transepithelial Cl− transport. Our study is a pharmacological analysis with the aim of addressing this issue, which is of major physiological significance in cases of pulmonary oedema from any cause. We measured the rate of transepithelial liquid movement (Jv) with 125I‐albumin, in the in situ perfused adult rat lung. Transepithelial Cl− transport was studied with the use of the Cl− channel inhibitor NPPB in the resting state and during stimulation with the β2‐adrenergic agonist terbutaline. The study of Jv in these conditions revealed the following findings: (1) there is net absorption of excess of alveolar liquid in the resting, unstimulated state, which is predominantly amiloride sensitive; (2) inhibition of Cl− transport with NPPB in the resting state results in a 1.6‐fold increase in net absorption of alveolar liquid; and (3) the terbutaline‐stimulated net absorption of the excess liquid is enhanced by 2.8‐fold in the presence of NPPB. Our results are suggestive of the functional presence of secretory, but not absorptive, Cl− mechanisms and show that transepithelial Cl− transport is not part of the mechanism underlying lung liquid clearance in response to β‐adrenergic stimulation.
Is there a nitrergic modulation of the rat external anal sphincter?
Authors: Evers J. , Buffini M. , Craven S. , O’Connell P. R. , Jones J. F. X.
Published: August 2012

New findings

What is the central question of this study?

Nitric oxide is known to relax the internal anal sphincter, but its effect on the external anal sphincter is unknown. A topical NO donor (nitroglycerin) is used as an alternative to internal sphincterotomy in the treatment of chronic anal fissures. We investigated the potential effects of nitric oxide on the external anal sphincter and its motor nerve supply.

What is the main finding and its importance?

This study is the first to investigate the effect of NO on the external anal sphincter and shows that its contraction is not modulated by NO, by pudendal nitrergic fibres or by NO diffusion from neighbouring nitrergic plexuses of the anal canal.

Nitric oxide is known to relax the internal anal sphincter, but its effect on the external anal sphincter (EAS) is unknown. The aim of this study was to investigate whether there is a nitrergic nerve plexus that modulates the EAS, similar to that found in oesophageal striated muscle. An in vitro ring preparation of rat anal canal was used to evaluate the effects of the nitric oxide synthase inhibitor Nω‐nitro‐l‐arginine (l‐NNA) and the NO donor sodium nitroprusside (SNP) on the EAS in conditions of neuromuscular blockade and the effect of SNP on nerve‐evoked contractions. Immunohistological experiments were conducted to determine whether the neuronal isoform of nitric oxide synthase (nNOS) is present in the EAS. During direct muscle stimulation neither l‐NNA (P= 0.32) nor SNP (P= 0.19) significantly changed the EF50, which is the frequency at which 50% of maximal contraction is reached, compared with a time‐dependent control. Nerve‐evoked contractions were also not altered by addition of SNP to the tissue bath. Immunohistohistological experiments clearly showed co‐localization of nNOS‐positive nerve fibres at motor endplates of the oesophagus but not in the EAS. The internal anal sphincter was richly innervated by nitrergic fibres, but these did not extend into the EAS. In conclusion, there are no nitrergic motor fibres innervating the EAS, neurotransmission at the motor endplates is not affected by NO, and NO does not affect muscle force directly in conditions of neuromuscular blockade. There is, therefore, no evidence that EAS contraction is directly modulated by NO or by pudendal nitrergic fibres or diffusion from neighbouring nitrergic plexuses of the anal canal.
Sweat loss during heat stress contributes to subsequent reductions in lower‐body negative pressure tolerance
Authors: Lucas Rebekah A. I. , Ganio Matthew S. , Pearson James , Crandall Craig G.
Published: August 2012

New findings

What is the central question of this study?

Heat stress compromises blood pressure control, reducing an individual's tolerance to a simulated hemorrhagic challenge. The contribution of sweating, and the resulting loss of total body water, during heat stress on heat‐induced reductions in haemorrhagic tolerance is unknown.

What is the main finding and its importance?

Unreplaced sweat loss and the associated reduction in blood volume contribute to reductions in haemorrhagic tolerance in heat‐stressed individuals; however, this impairment is secondary to the negative impact of heat stress itself. These findings highlight the importance of adequate hydration in individuals who are exposed to heat stress and are at a higher risk for a haemorrhagic injury, such as soldiers, firefighters and construction workers.

The contribution of sweating to heat stress‐induced reductions in haemorrhagic tolerance is not known. This study tested the hypothesis that fluid loss due to sweating contributes to reductions in simulated haemorrhagic tolerance in conditions of heat stress. Eight subjects (35 ± 8 years old; 77 ± 5 kg) underwent a normothermic time control and two heat stress trials (randomized). The two heat stress trials were as follows: (i) with slow intravenous infusion of lactated Ringer solution sufficient to offset sweat loss (IV trial); or (ii) without intravenous infusion (dehydration; DEH trial). Haemorrhage was simulated via progressive lower‐body negative pressure (LBNP) to presyncope after core body (intestinal) temperature was raised by ∼1.5°C using a water‐perfused suit or a normothermic time control period. The LBNP tolerance was quantified via a cumulative stress index. Middle cerebral artery blood velocity (transcranial Doppler) and mean blood pressure (Finometer®) were measured continuously. Relative changes in plasma volume were calculated from haematocrit and haemoglobin. Increases in core body temperature and sweat loss (∼1.6% body mass deficit) were similar (P > 0.05) between heat stress trials. Slow intravenous infusion (1.2 ± 0.3 litres) prevented heat‐induced reductions in plasma volume (IV trial, −0.6 ± 6.1%; and DEH trial, −6.6 ± 5.1%; P= 0.01). Intravenous infusion improved LBNP tolerance (632 ± 64 mmHg min) by ∼20% when compared with the DEH trial (407 ± 117 mmHg min; P= 0.01), yet tolerance remained 44% lower in the IV trial relative to the time control normothermic trial (1138 ± 183 mmHg min; P < 0.01). These data indicate that although sweat‐induced dehydration impairs simulated haemorrhagic tolerance, this impairment is secondary to the negative impact of heat stress itself.
Modeling the Onset of Gas Entrainment in a Reduced T-Junction With Co-Current Stratified Gas-Liquid Flow
Authors: Bowden Robert C. , Hassan Ibrahim G.
Published: August 2012

A model was developed to predict the onset of gas entrainment in a single downward oriented branch. The branch was installed on a horizontal square cross-sectional channel having a smooth stratified co-currently flowing gas-liquid regime in the inlet region. The branch flow was simulated as a three-dimensional point-sink while the run flow was treated as a uniform velocity at the critical dip. Experiments were performed to determine the critical liquid flow distribution between the run and the branch. A correlation was developed relating the branch Froude number to the ratio of the superficial liquid mass fluxes in the run and the branch. The correlation was used as a boundary condition in the model. A methodology was developed using digital imaging to record the coordinates of the critical dip at the onset of as entrainment. The dip angle was found to range between 40 to 60 degrees and constant dip angles of 40, 50 and 60 degrees were selected as boundary conditions. The critical height was predicted to within 50% of experiments with the error attributed to differences in the modeled and experimental geometries. A semi-empirical analysis using the experimental geometry yielded a critical height prediction to within 20% of experimental results.
Influence of Rotating Band Construction on Gun Tube Loading—Part I: Numerical Approach
Authors: Keinänen Heikki , Moilanen Seppo , Tervokoski Janne , Toivola Juha
Published: August 2012

The effects of changes in geometries and material properties of rotating band and long range artillery projectile shell body on gun tube stress are presented. The results are based on numerical calculations (finite element analysis, FEA). Numerical explicit dynamic analyses were performed assuming elastic–plastic material behavior and nonlinear kinematics. Mechanical loading of shell body was controlled by pressure–time relationship based on the simulation of internal ballistic cycle. One degree slice of projectile and forcing cone section of gun tube was modeled as simplified smooth bore 3D analysis model. The results were in agreement with the measured results in firing trials and also with the results presented in open literature. Although simplified computations were used, the influences of the structural modifications of the rotating band and the shell body were shown.
Discussion: “Effect of Corrugated Roughness on Developed Laminar Flow in Microtubes,” (Duan, Z. and Muzychka, Y. M., 2008, ASME Trans. J. Fluids Eng., 130, p. 031102)
Authors: Akyildiz F. Talay , Siginer Dennis A.
Published: August 2012

Fully developed continuum flow through corrugated tubes with slip at the boundary is solved by perturbations and the results are compared with the work of Duan and Muzychka (Duan and Muzychka, 2008, “Effects of Corrugated Roughness on Developed Laminar Flow in Microtubes,” ASME Trans. J. Fluids Eng., 130, p. 031102). This note brings out and corrects the errata and extends the results obtained.
Assessment of Wave Energy Extraction From Seas: Numerical Validation
Authors: Sheng Wanan , Lewis Anthony
Published: August 2012

In developing a wave energy converter (WEC), assessing and rating the device is a difficult, but important issue. Conventionally, a large scaled device (maybe large enough for accommodating a power takeoff (PTO) system) or prototype device is needed to be tested in wave tanks or in seas in different wave conditions so that a power matrix for the device can be defined using scaling or interpolation/extrapolation methods. Alternatively, a pure numerical simulation in time-domain may be used for assessing the power capture capacities of wave energy devices. For the former, it is convincing, but can be especially difficult in the early stages of development, when small scaled models are normally used; and for the latter, the pure numerical simulation may not be very reliable and convincing, especially when the dynamic problem is very complicated. In this paper, a method for assessing the captured wave power for a device from its power capture response is presented. In the proposed method, a measured or calculated linear power capture response of the device is combined with wave spectrum to compute the average captured power function. Once the average captured power function is obtained, the overall average captured power corresponding to the wave state can be easily calculated. If a linear power capture response is obtained from a model test, the power assessment based on this proposed method can be very convincing and reliable. To illustrate the application of the proposed method, an example of a fully linear dynamic system, including the linear hydrodynamics of the floating structure and a linear power takeoff, is considered. For such a system, the frequency-domain analysis can be employed to obtain the performance of the floating device under waves and the power takeoff system. The hydrodynamic performance of the wave energy converter is then used to define the power capture response and to calculate the average captured power functions in different sea states. Then, the captured power of the device in different sea states, i.e, the power matrix, can be calculated, and accordingly, the device can be assessed and rated. To validate the proposed method, a time-domain analysis is also performed for a cross-check. In the time-domain analysis, the hydrodynamic coefficients and responses are first assessed in frequency-domain, and then transformed into the relevant terms by means of impulse response functions for establishing the time-domain (TD) equation. By comparing the results from frequency-domain and time-domain analyses of irregular waves, it can be concluded that the proposed wave energy capture assessment method can be used in assessing or rating the device.
Perception of pitch location within a speaker’s range: Fundamental frequency, voice quality and speaker sex
Authors: Bishop Jason , Keating Patricia
Published: August 2012

How are listeners able to identify whether the pitch of a brief isolated sample of an unknown voice is high or low in the overall pitch range of that speaker? Does the speaker’s voice quality convey crucial information about pitch level? Results and statistical models of two experiments that provide answers to these questions are presented. First, listeners rated the pitch levels of vowels taken over the full pitch ranges of male and female speakers. The absolute f0 of the samples was by far the most important determinant of listeners’ ratings, but with some effect of the sex of the speaker. Acoustic measures of voice quality had only a very small effect on these ratings. This result suggests that listeners have expectations about f0s for average speakers of each sex, and judge voice samples against such expectations. Second, listeners judged speaker sex for the same speech samples. Again, absolute f0 was the most important determinant of listeners’ judgments, but now voice quality measures also played a role. Thus it seems that pitch level judgments depend on voice quality mostly indirectly, through its information about sex. Absolute f0 is the most important information for deciding both pitch level and speaker sex.
The ability of cochlear implant users to use temporal envelope cues recovered from speech frequency modulation
Authors: Won Jong Ho , Lorenzi Christian , Nie Kaibao , Li Xing , Jameyson Elyse M. , Drennan Ward R. , Rubinstein Jay T.
Published: August 2012

Previous studies have demonstrated that normal-hearing listeners can understand speech using the recovered “temporal envelopes,” i.e., amplitude modulation (AM) cues from frequency modulation (FM). This study evaluated this mechanism in cochlear implant (CI) users for consonant identification. Stimuli containing only FM cues were created using 1, 2, 4, and 8-band FM-vocoders to determine if consonant identification performance would improve as the recovered AM cues become more available. A consistent improvement was observed as the band number decreased from 8 to 1, supporting the hypothesis that (1) the CI sound processor generates recovered AM cues from broadband FM, and (2) CI users can use the recovered AM cues to recognize speech. The correlation between the intact and the recovered AM components at the output of the sound processor was also generally higher when the band number was low, supporting the consonant identification results. Moreover, CI subjects who were better at using recovered AM cues from broadband FM cues showed better identification performance with intact (unprocessed) speech stimuli. This suggests that speech perception performance variability in CI users may be partly caused by differences in their ability to use AM cues recovered from FM speech cues.
Blind extraction and localization of sound sources using point sources based approaches
Authors: Wu Sean F. , Zhu Na
Published: August 2012

This paper presents theoretical models for blind sound source localization and separation of the signals emitted by arbitrary point sources in free space. Source localizations are achieved by a model based approach that accounts for the spherical spreading of an acoustic wave and utilizes an iterative triangulation, based on the signals measured by a three-dimensional microphone array. Once source locations are determined, the source signals are separated by using the point source separation (PSS) method, which is valid for all types of signals, including harmonic, continuous, transient, random, narrowband and broadband. General solutions for signals separation are presented. Theoretically, PSS can reconstruct the individual source signals exactly. This is because it employs the free-space Green’s function, which defines the exact correlation among individual sources and measurement microphones. To validate PSS, numerical simulations are carried out and results are compared with those obtained by FastICA (Independent Component Analysis) code. The impacts of various parameters such as the microphone configuration, type of source signals, signal to noise ratio, number of microphones and source localization errors on the quality of signals separation by using PSS and FastICA are examined. The advantages and disadvantages of PSS and FastICA are compared and discussed.
Effects of deafness on acoustic characteristics of American English tense/lax vowels in maternal speech to infants
Authors: Kondaurova Maria V. , Bergeson Tonya R. , Dilley Laura C.
Published: August 2012

Recent studies have demonstrated that mothers exaggerate phonetic properties of infant-directed (ID) speech. However, these studies focused on a single acoustic dimension (frequency), whereas speech sounds are composed of multiple acoustic cues. Moreover, little is known about how mothers adjust phonetic properties of speech to children with hearing loss. This study examined mothers’ production of frequency and duration cues to the American English tense/lax vowel contrast in speech to profoundly deaf (N = 14) and normal-hearing (N = 14) infants, and to an adult experimenter. First and second formant frequencies and vowel duration of tense (/i/, /u/) and lax (/I/, /ʊ/) vowels were measured. Results demonstrated that for both infant groups mothers hyperarticulated the acoustic vowel space and increased vowel duration in ID speech relative to adult-directed speech. Mean F2 values were decreased for the /u/ vowel and increased for the /I/ vowel, and vowel duration was longer for the /i/, /u/, and /I/ vowels in ID speech. However, neither acoustic cue differed in speech to hearing-impaired or normal-hearing infants. These results suggest that both formant frequencies and vowel duration that differentiate American English tense/lx vowel contrasts are modified in ID speech regardless of the hearing status of the addressee.
Ventricular pressures in phonating excised larynges
Authors: Alipour Fariborz , Scherer Ronald C.
Published: August 2012

Pressure in the laryngeal ventricle was measured with a beveled needle connected to a pressure transducer in excised canine larynges. Air pressures within the ventricle were obtained for different adduction levels of the true vocal folds (TVFs), false vocal folds (FVFs), and subglottal pressures (Ps). Results indicated that the air pressures in the ventricle appear to be strongly related to the motion of the FVFs rather than to the effects of TVF vibration. Both dc and ac pressures depend on FVF adduction, amplitude of motion of the FVFs, and whether the FVFs touch each other during the vibratory cycle. Mean and peak-to-peak pressures in the ventricle were as high as 65% of the mean and peak-to-peak Ps, respectively, when the FVFs vibrated with large amplitude and contact each cycle. If the glottis was not closed, a medial movement of the FVFs appeared to create a positive pressure pulse on the Ps signal due to an increase in the laryngeal flow resistance. The electroglottograph signal showed evidence of tissue contact for both the TVFs and the FVFs. The study suggests that the laryngeal ventricle acts as a relatively independent aero-acoustic chamber that depends primarily upon the motion of the FVFs.
Quality and loudness judgments for music subjected to compression limiting
Authors: Croghan Naomi B. H. , Arehart Kathryn H. , Kates James M.
Published: August 2012

Dynamic-range compression (DRC) is used in the music industry to maximize loudness. The amount of compression applied to commercial recordings has increased over time due to a motivating perspective that louder music is always preferred. In contrast to this viewpoint, artists and consumers have argued that using large amounts of DRC negatively affects the quality of music. However, little research evidence has supported the claims of either position. The present study investigated how DRC affects the perceived loudness and sound quality of recorded music. Rock and classical music samples were peak-normalized and then processed using different amounts of DRC. Normal-hearing listeners rated the processed and unprocessed samples on overall loudness, dynamic range, pleasantness, and preference, using a scaled paired-comparison procedure in two conditions: un-equalized, in which the loudness of the music samples varied, and loudness-equalized, in which loudness differences were minimized. Results indicated that a small amount of compression was preferred in the un-equalized condition, but the highest levels of compression were generally detrimental to quality, whether loudness was equalized or varied. These findings are contrary to the “louder is better” mentality in the music industry and suggest that more conservative use of DRC may be preferred for commercial music.
Effects of speaker variability and noise on Mandarin fricative identification by native and non-native listeners
Authors: Lee Chao-Yang , Zhang Yu , Li Ximing , Tao Liang , Bond Z. S.
Published: August 2012

Speaker variability and noise are two common sources of acoustic variability. The goal of this study was to examine whether these two sources of acoustic variability affected native and non-native perception of Mandarin fricatives to different degrees. Multispeaker Mandarin fricative stimuli were presented to 40 native and 52 non-native listeners in two presentation formats (blocked by speaker and mixed across speakers). The stimuli were also mixed with speech-shaped noise to create five levels of signal-to- noise ratios. The results showed that noise affected non-native identification disproportionately. By contrast, the effect of speaker variability was comparable between the native and non-native listeners. Confusion patterns were interpreted with reference to the results of acoustic analysis, suggesting native and non-native listeners used distinct acoustic cues for fricative identification. It was concluded that not all sources of acoustic variability are treated equally by native and non-native listeners. Whereas noise compromised non-native fricative perception disproportionately, speaker variability did not pose a special challenge to the non-native listeners.
Are human spontaneous otoacoustic emissions generated by a chain of coupled nonlinear oscillators?
Authors: Wit Hero P. , van Dijk Pim
Published: August 2012

Spontaneous otoacoustic emissions (SOAEs) are generated by self-sustained cochlear oscillators. Properties of a computational model for a linear array of active oscillators with nearest neighbor coupling are investigated. The model can produce many experimentally well-established properties of SOAEs.
Lamb modes with multiple zero-group velocity points in an orthotropic plate
Authors: Hussain Takasar , Ahmad Faiz
Published: August 2012

In this paper the spectrum of Lamb modes in an orthotropic plate is studied. Infinitely many modes are found which undergo a change of sign in their slopes twice, thus leading to two zero-group velocity points. A few modes possessing three such points also exist.
Scattering of focused ultrasonic beams by cavities in a solid half-space
Authors: Kabiri Rahani Ehsan , Hajzargarbashi Talieh , Kundu Tribikram
Published: August 2012

The ultrasonic field generated by a point focused acoustic lens placed in a fluid medium adjacent to a solid half-space, containing one or more spherical cavities, is modeled. The semi-analytical distributed point source method (DPSM) is followed for the modeling. This technique properly takes into account the interaction effect between the cavities placed in the focused ultrasonic field, fluid-solid interface and the lens surface. The approximate analytical solution that is available in the literature for the single cavity geometry is very restrictive and cannot handle multiple cavity problems. Finite element solutions for such problems are also prohibitively time consuming at high frequencies. Solution of this problem is necessary to predict when two cavities placed in close proximity inside a solid can be distinguished by an acoustic lens placed outside the solid medium and when such distinction is not possible.
Psychophysically based site selection coupled with dichotic stimulation improves speech recognition in noise with bilateral cochlear implants
Authors: Zhou Ning , Pfingst Bryan E.
Published: August 2012

The ability to perceive important features of electrical stimulation varies across stimulation sites within a multichannel implant. The aim of this study was to optimize speech processor MAPs for bilateral implant users by identifying and removing sites with poor psychophysical performance. The psychophysical assessment involved amplitude-modulation detection with and without a masker, and a channel interaction measure quantified as the elevation in modulation detection thresholds in the presence of the masker. Three experimental MAPs were created on an individual-subject basis using data from one of the three psychophysical measures. These experimental MAPs improved the mean psychophysical acuity across the electrode array and provided additional advantages such as increasing spatial separations between electrodes and/or preserving frequency resolution. All 8 subjects showed improved speech recognition in noise with one or more experimental MAPs over their everyday-use clinical MAP. For most subjects, phoneme and sentence recognition in noise were significantly improved by a dichotic experimental MAP that provided better mean psychophysical acuity, a balanced distribution of selected stimulation sites, and preserved frequency resolution. The site-selection strategies serve as useful tools for evaluating the importance of psychophysical acuities needed for good speech recognition in implant users.
Obtaining reliable phase-gradient delays from otoacoustic emission data
Authors: Shera Christopher A. , Bergevin Christopher
Published: August 2012

Reflection-source otoacoustic emission phase-gradient delays are widely used to obtain noninvasive estimates of cochlear function and properties, such as the sharpness of mechanical tuning and its variation along the length of the cochlear partition. Although different data-processing strategies are known to yield different delay estimates and trends, their relative reliability has not been established. This paper uses in silico experiments to evaluate six methods for extracting delay trends from reflection-source otoacoustic emissions (OAEs). The six methods include both previously published procedures (e.g., phase smoothing, energy-weighting, data exclusion based on signal-to-noise ratio) and novel strategies (e.g., peak-picking, all-pass factorization). Although some of the methods perform well (e.g., peak-picking), others introduce substantial bias (e.g., phase smoothing) and are not recommended. In addition, since standing waves caused by multiple internal reflection can complicate the interpretation and compromise the application of OAE delays, this paper develops and evaluates two promising signal-processing strategies, the first based on time-frequency filtering using the continuous wavelet transform and the second on cepstral analysis, for separating the direct emission from its subsequent reflections. Altogether, the results help to resolve previous disagreements about the frequency dependence of human OAE delays and the sharpness of cochlear tuning while providing useful analysis methods for future studies.
Blast noise classification with common sound level meter metrics
Authors: Cvengros Robert M. , Valente Dan , Nykaza Edward T. , Vipperman Jeffrey S.
Published: August 2012

A common set of signal features measurable by a basic sound level meter are analyzed, and the quality of information carried in subsets of these features are examined for their ability to discriminate military blast and non-blast sounds. The analysis is based on over 120 000 human classified signals compiled from seven different datasets. The study implements linear and Gaussian radial basis function (RBF) support vector machines (SVM) to classify blast sounds. Using the orthogonal centroid dimension reduction technique, intuition is developed about the distribution of blast and non-blast feature vectors in high dimensional space. Recursive feature elimination (SVM-RFE) is then used to eliminate features containing redundant information and rank features according to their ability to separate blasts from non-blasts. Finally, the accuracy of the linear and RBF SVM classifiers is listed for each of the experiments in the dataset, and the weights are given for the linear SVM classifier.
Phononic glass: A robust acoustic-absorption material
Authors: Jiang Heng , Wang Yuren
Published: August 2012

In order to achieve strong wide band acoustic absorption under high hydrostatic pressure, an interpenetrating network structure is introduced into the locally resonant phononic crystal to fabricate a type of phononic composite material called “phononic glass.” Underwater acoustic absorption coefficient measurements show that the material owns high underwater sound absorption coefficients over 0.9 in 12–30 kHz. Moreover, the quasi-static compressive behavior shows that the phononic glass has a compressive strength over 5 MPa which is crucial for underwater applications.
Asynchronous glimpsing of speech: Spread of masking and task set-size
Authors: Ozmeral Erol J. , Buss Emily , Hall Joseph W.
Published: August 2012

Howard-Jones and Rosen [(1993). J. Acoust. Soc. Am. 93, 2915–2922] investigated the ability to integrate glimpses of speech that are separated in time and frequency using a “checkerboard” masker, with asynchronous amplitude modulation (AM) across frequency. Asynchronous glimpsing was demonstrated only for spectrally wide frequency bands. It is possible that the reduced evidence of spectro-temporal integration with narrower bands was due to spread of masking at the periphery. The present study tested this hypothesis with a dichotic condition, in which the even- and odd-numbered bands of the target speech and asynchronous AM masker were presented to opposite ears, minimizing the deleterious effects of masking spread. For closed-set consonant recognition, thresholds were 5.1–8.5 dB better for dichotic than for monotic asynchronous AM conditions. Results were similar for closed-set word recognition, but for open-set word recognition the benefit of dichotic presentation was more modest and level dependent, consistent with the effects of spread of masking being level dependent. There was greater evidence of asynchronous glimpsing in the open-set than closed-set tasks. Presenting stimuli dichotically supported asynchronous glimpsing with narrower frequency bands than previously shown, though the magnitude of glimpsing was reduced for narrower bandwidths even in some dichotic conditions.