bluuebunny/crossref_metadata_2025 huggingface dataset:
Low frequency sound propagation in activated carbon
Authors: Bechwati F. , Avis M. R. , Bull D. J. , Cox T. J. , Hargreaves J. A. , Moser D. , Ross D. K. , Umnova O. , Venegas R.
Published: July 2012

Activated carbon can adsorb and desorb gas molecules onto and off its surface. Research has examined whether this sorption affects low frequency sound waves, with pressures typical of audible sound, interacting with granular activated carbon. Impedance tube measurements were undertaken examining the resonant frequencies of Helmholtz resonators with different backing materials. It was found that the addition of activated carbon increased the compliance of the backing volume. The effect was observed up to the highest frequency measured (500 Hz), but was most significant at lower frequencies (at higher frequencies another phenomenon can explain the behavior). An apparatus was constructed to measure the effective porosity of the activated carbon as well as the number of moles adsorbed at sound pressures between 104 and 118 dB and low frequencies between 20 and 55 Hz. Whilst the results were consistent with adsorption affecting sound propagation, other phenomena cannot be ruled out. Measurements of sorption isotherms showed that additional energy losses can be caused by water vapor condensing onto and then evaporating from the surface of the material. However, the excess absorption measured for low frequency sound waves is primarily caused by decreases in surface reactance rather than changes in surface resistance.
Notionally steady background noise acts primarily as a modulation masker of speech
Authors: Stone Michael A. , Füllgrabe Christian , Moore Brian C. J.
Published: July 2012

Stone et al. [J. Acoust. Soc Am. 130, 2874–2881 (2011)], using vocoder processing, showed that the envelope modulations of a notionally steady noise were more effective than the envelope energy as a masker of speech. Here the same effect is demonstrated using non-vocoded signals. Speech was filtered into 28 channels. A masker centered on each channel was added to the channel signal at a target-to-background ratio of −5 or −10 dB. Maskers were sinusoids or noise bands with bandwidth 1/3 or 1 ERBN (ERBN being the bandwidth of “normal” auditory filters), synthesized with Gaussian (GN) or low-noise (LNN) statistics. To minimize peripheral interactions between maskers, odd-numbered channels were presented to one ear and even to the other. Speech intelligibility was assessed in the presence of each “steady” masker and that masker 100% sinusoidally amplitude modulated (SAM) at 8 Hz. Intelligibility decreased with increasing envelope fluctuation of the maskers. Masking release, the difference in intelligibility between the SAM and its “steady” counterpart, increased with bandwidth from near-zero to around 50 percentage points for the 1-ERBN GN. It is concluded that the sinusoidal and GN maskers behaved primarily as energetic and modulation maskers, respectively.
Horizontal directivity of low- and high-frequency energy in speech and singing
Authors: Monson Brian B. , Hunter Eric J. , Story Brad H.
Published: July 2012

Speech and singing directivity in the horizontal plane was examined using simultaneous multi-channel full-bandwidth recordings to investigate directivity of high-frequency energy, in particular. This method allowed not only for accurate analysis of running speech using the long-term average spectrum, but also for examination of directivity of separate transient phonemes. Several vocal production factors that could affect directivity were examined. Directivity differences were not found between modes of production (speech vs singing) and only slight differences were found between genders and production levels (soft vs normal vs loud), more pronounced in the higher frequencies. Large directivity differences were found between specific voiceless fricatives, with /s,∫/ more directional than /f,θ/ in the 4, 8, 16 kHz octave bands.
Collective bubble dynamics near a surface in a weak acoustic standing wave field
Authors: Xi Xiaoyu , Cegla Frederic , Mettin Robert , Holsteyns Frank , Lippert Alexander
Published: July 2012

The transport of bubbles to a neighboring surface is very important in surface chemistry, bioengineering, and ultrasonic cleaning, etc. This paper proposes a multi-bubble transport method by using an acoustic standing wave field and establishes a model that explains the multi-bubble translation by expressing the balance between Bjerknes forces and hydrodynamic forces on a bubble in a liquid medium. Results indicated that the influence of primary Bjerknes force, secondary Bjerknes force, and buoyancy force on the bubble translation depends on the position of the target bubble in the acoustic field. Moreover, it was found that increasing the size of a bubble or pressure amplitude can accelerate the bubble motion and enhance the bubble-bubble interaction. The secondary Bjerknes force between two bubbles can switch from an attractive one when they oscillate in phase to a repulsive one when the bubble oscillations are out of phase. These findings provide an insight into the multi-bubble translation near a surface and can be applied to future bubble motion control studies, especially in drug delivery, sonoporation, and ultrasonic cleaning.
Parametric plate-bridge dynamic filter model of violin radiativity
Authors: Bissinger George
Published: July 2012

A hybrid, deterministic-statistical, parametric “dynamic filter” model of the violin’s radiativity profile [characterized by an averaged-over-sphere, mean-square radiativity ⟨R(ω)2⟩] is developed based on the premise that acoustic radiation depends on (1) how strongly it vibrates [characterized by the averaged-over-corpus, mean-square mobility ⟨Y(ω)2⟩] and (2) how effectively these vibrations are turned into sound, characterized by the radiation efficiency, which is proportional to ⟨R(ω)2⟩/⟨Y(ω)2⟩. Two plate mode frequencies were used to compute 1st corpus bending mode frequencies using empirical trend lines; these corpus bending modes in turn drive cavity volume flows to excite the two lowest cavity modes A0 and A1. All widely-separated, strongly-radiating corpus and cavity modes in the low frequency deterministic region are then parameterized in a dual-Helmholtz resonator model. Mid-high frequency statistical regions are parameterized with the aid of a distributed-excitation statistical mobility function (no bridge) to help extract bridge filter effects associated with (a) bridge rocking mode frequency changes and (b) bridge-corpus interactions from 14-violin-average, excited-via-bridge ⟨Y(ω)2⟩ and ⟨R(ω)2⟩. Deterministic-statistical regions are rejoined at ∼630 Hz in a mobility-radiativity “trough” where all violin quality classes had a common radiativity. Simulations indicate that typical plate tuning has a significantly weaker effect on radiativity profile trends than bridge tuning.
Shadow effects in simulated ultrasound images derived from computed tomography images using a focused beam tracing model
Authors: Pham An Hoai , Lundgren Bo , Stage Bjarne , Møller Pedersen Mads , Bachmann Nielsen Michael , Hemmsen Martin Christian , Arendt Jensen Jørgen
Published: July 2012

Simulation of ultrasound images based on computed tomography (CT) data has previously been performed with different approaches. Shadow effects are normally pronounced in ultrasound images, so they should be included in the simulation. In this study, a method to capture the shadow effects has been developed, which makes the simulated ultrasound images appear more realistic. The method using a focused beam tracing model gives diffuse shadows that are similar to the ones observed in measurements on real objects. Ultrasound images of a cod (Gadus morhua) were obtained with a BK Medical 2202 ProFocus ultrasound scanner (BK Medical, Herlev, Denmark) equipped with a dedicated research interface giving access to beamformed radio frequency data. CT images were obtained with an Aquilion ONE Toshiba CT scanner (Toshiba Medical Systems Corp., Tochigi, Japan). CT data were mapped from Hounsfield units to backscatter strength, attenuation coefficients, and characteristic acoustic impedance. The focused beam tracing model was used to create maps of the transmission coefficient and scattering strength maps. Field II was then used to simulate an ultrasound image of 38.9 × 55.3 × 4.5 mm, using 106 point scatterers. As there is no quantitative method to assess quality of a simulated ultrasound image compared to a measured one, visual inspection was used for evaluation.
An acousto-optic beamformer
Authors: Torras-Rosell Antoni , Barrera-Figueroa Salvador , Jacobsen Finn
Published: July 2012

There is a great variety of beamforming techniques that can be used for localization of sound sources. The differences among them usually lie in the array layout or in the specific signal processing algorithm used to compute the beamforming output. Any beamforming system consists of a finite number of transducers, which makes beamforming methods vulnerable to spatial aliasing above a certain frequency. The present work uses the acousto-optic effect, i.e., the interaction between sound and light, to localize sound sources in a plane. The use of a beam of light as the sensing element is equivalent to a continuous line aperture with an infinite number of microphones. This makes the proposed acousto-optic beamformer immune to spatial aliasing. This unique feature is illustrated by means of simulations and experimental results within the entire audible frequency range. For ease of comparison, the study is supplemented with measurements carried out with a line array of microphones.
Recovery of individual head-related transfer functions from a small set of measurements
Authors: Xie Bo-Sun
Published: July 2012

Head-related transfer functions (HRTFs) vary with individuals, and in practice, measuring HRTFs with high directional resolution for each individual is tiresome. Based on a basis functions representation of HRTFs, the present work proposes a method for recovering individual HRTFs from a small set of measurements. The HRTFs are represented by a combination of a small set of spatial basis functions (SBFs) with frequency- and individual-dependent weights. The SBFs are derived by applying spatial principal component analysis to a baseline HRTF dataset with high directional resolution. The individual weights for any subject outside the dataset are estimated from measurements at a few source directions, and then the HRTFs with high directional resolution are recovered by combining the SBFs and the individual weights. In an illustrative case, the SBFs derived from a baseline dataset that includes 20 subjects are used to recover the HRTF magnitudes for six subjects outside the baseline dataset. Results show that individual HRTF magnitudes can be recovered from measurements at 73 directions with a mean signal-to-distortion ratio of 19 dB. The proposed method is also applicable to recovering head-related impulse responses. The results of psychoacoustic experiments indicate that in most cases the recovered and measured HRTFs are indistinguishable.
Blast noise characteristics as a function of distance for temperate and desert climates
Authors: Valente Dan , Ronsse Lauren M. , Pater Larry , White Michael J. , Serwy Roger , Nykaza Edward T. , Swearingen Michelle E. , Albert Donald G.
Published: July 2012

Variability in received sound levels were investigated at distances ranging from 4 m to 16 km from a typical blast source in two locations with different climates and terrain. Four experiments were conducted, two in a temperate climate with a hilly terrain and two in a desert climate with a flat terrain, under a variety of meteorological conditions. Sound levels were recorded in three different directions around the source during the summer and winter seasons in each location. Testing occurred over the course of several days for each experiment during all 24 h of the day, and meteorological data were gathered throughout each experiment. The peak levels (LPk), C-weighted sound exposure levels (CSEL), and spectral characteristics of the received sound pressure levels were analyzed. The results show high variability in LPk and CSEL at distances beyond 2 km from the source for each experiment, which was not clearly explained by the time of day the blasts occurred. Also, as expected, higher frequency energy is attenuated more drastically than the lower frequency energy as the distance from the source increases. These data serve as a reference for long-distance blast sound propagation.
Shipping noise in whale habitat: Characteristics, sources, budget, and impact on belugas in Saguenay–St. Lawrence Marine Park hub
Authors: Gervaise Cédric , Simard Yvan , Roy Nathalie , Kinda Bazile , Ménard Nadia
Published: July 2012

A continuous car ferry line crossing the Saguenay Fjord mouth and traffic from the local whale-watching fleet introduce high levels of shipping noise in the heart of the Saguenay–St. Lawrence Marine Park. To characterize this noise and examine its potential impact on belugas, a 4-hydrophone array was deployed in the area and continuously recorded for five weeks in May–June 2009. The source levels of the different vessel types showed little dependence on vessel size or speed increase. Their spectral range covered 33 dB. Lowest noise levels occurred at night, when ferry crossing pace was reduced, and daytime noise peaked during whale-watching tour departures and arrivals. Natural ambient noise prevailed 9.4% of the time. Ferry traffic added 30–35 dB to ambient levels above 1 kHz during crossings, which contributed 8 to 14 dB to hourly averages. The whale-watching fleet added up to 5.6 dB during peak hours. Assuming no behavioral or auditory compensation, half of the time, beluga potential communication range was reduced to less than ∼30% of its expected value under natural noise conditions, and to less than ∼15% for one quarter of the time, with little dependence on call frequency. The echolocation band for this population of belugas was also affected by the shipping noise.
Time domain attenuation estimation method from ultrasonic backscattered signals
Authors: Ghoshal Goutam , Oelze Michael L.
Published: July 2012

Ultrasonic attenuation is important not only as a parameter for characterizing tissue but also for compensating other parameters that are used to classify tissues. Several techniques have been explored for estimating ultrasonic attenuation from backscattered signals. In the present study, a technique is developed to estimate the local ultrasonic attenuation coefficient by analyzing the time domain backscattered signal. The proposed method incorporates an objective function that combines the diffraction pattern of the source/receiver with the attenuation slope in an integral equation. The technique was assessed through simulations and validated through experiments with a tissue mimicking phantom and fresh rabbit liver samples. The attenuation values estimated using the proposed technique were compared with the attenuation estimated using insertion loss measurements. For a data block size of 15 pulse lengths axially and 15 beamwidths laterally, the mean attenuation estimates from the tissue mimicking phantoms were within 10% of the estimates using insertion loss measurements. With a data block size of 20 pulse lengths axially and 20 beamwidths laterally, the error in the attenuation values estimated from the liver samples were within 10% of the attenuation values estimated from the insertion loss measurements.
Time-domain characterization of the acoustic damping of a perforated liner with bias flow
Authors: Zhong Zhiyuan , Zhao Dan
Published: July 2012

Combustion instabilities are caused by the interaction of unsteady heat releases and acoustic waves. To mitigate combustion instabilities, perforated liners, typically subjected to a low Mach number bias flow (a cooling flow through perforated holes), are fitted along the bounding walls of a combustor. They dissipate the acoustic waves by generating vorticity at the rims of perforated apertures. To investigate the absorption of plane waves by a perforated liner with bias flow, a time-domain numerical model of a cylindrical lined duct is developed. The liners’ damping mechanism is characterized by using a time-domain “compliance.” The development of such time-domain compliance is based on simplified or unsimplified Rayleigh conductivity. Numerical simulations of two different configurations of lined duct systems are performed by combining a 1D acoustic wave model with the compliance model. Comparison is then made between the results from the present models, and those from the experiment and the frequency-domain model of previous investigation [Eldredge and Dowling, J. Fluid Mech. 485, 307–335(2003)]. Good agreement is observed. This confirms that the present model can be used to simulate the propagation and dissipation of acoustic plane waves in a lined duct in real-time.
Analysis of absorption performances of anechoic layers with steel plate backing
Authors: Meng Hao , Wen Jihong , Zhao Honggang , Lv Linmei , Wen Xisen
Published: July 2012

Rubber layers with air-filled cavities or local resonance scatters can be used as anechoic coatings. A lot of researches have focused on the absorption mechanism of the anechoic coatings. As the anechoic coatings are bonded to the hull of submarine, the vibration of the hull should not be neglected when the analysis of the absorption characters is carried out. Therefore, it is more reasonable to treat the anechoic coating and the backing as a whole when the acoustic performance is analyzed. Considering the effects of the steel plate backing, the sound absorption performances on different models of anechoic coatings are investigated in this paper. The Finite Element Method is used to illustrate the vibrational behaviors of the anechoic coatings under the steel backings by which the displacement contours is obtained for analysis. The theoretical results show that an absorption peak is induced by the resonance of the steel slab and rubber layer. At the frequency of this absorption peak, the steel plate and the coating vibrates longitudinally like a mass-spring system in which the steel slab serves for mass and the coating layer is the spring. To illuminate the effects of the steel slab backing on the acoustic absorption, the thicknesses of the steel slab and the anechoic layer are discussed. Finally, an experiment is performed and the results show a good agreement with the theoretical analysis.
Phase mapping of acoustic sources by beamforming and iterative far field monopole substitution
Authors: Castellini Paolo , Sopranzetti Francesca
Published: July 2012

The first aim of this paper is to give emphasis to the importance of assessing phase information when reconstructing and mapping a sound field. In fact, in acoustic analysis phase distribution is frequently simply either not considered or ignored, even though it can supply very useful information for the understanding of the mapping itself or for further analyses. In this paper a procedure to carry out phase mapping of acoustic sources in beamforming measurement is illustrated. The second aim of this paper is to propose a straightforward iterative optimization algorithm based on the monopole substitution starting from beamforming results. It allows for the reconstruction of sound field without the use of any matrix inversion. Both numerical and experimental validations of the method are presented. Results shown hereafter prove the effectiveness of the approach.
Surface decomposition method for near-field acoustic holography
Authors: Valdivia Nicolas P. , Williams Earl G. , Herdic Peter C. , Houston Brian
Published: July 2012

Near-field acoustic holography reconstruction of the acoustic field at the surface of an arbitrarily shaped radiating structure from pressure measurements at a nearby conformal surface is obtained from the solution of a boundary integral equation. This integral equation is discretized using the equivalent source method and transformed into a matrix system that can be solved using iterative regularization methods that counteract the effect of noise on the measurements. This work considers the case when the resultant matrix system is so large that it cannot be explicitly formed and iterative methods of solution cannot be directly implemented. In this case the method of surface decomposition is proposed, where the measurement surface is divided into smaller nonoverlapping subsurfaces. Each subsurface is used to form a smaller matrix system that is solved and the result joined together to generate a global solution to the original matrix system. Numerically generated data are used to study the use of subsurface extensions to increase the continuity of the global solution, and investigate the size of the subsurfaces, as well as the distance between the measurement and the vibrating surface. Finally a vibrating ship hull structure is considered as a physical example to apply and validate the proposed methodology.
Standards Meetings Calendar–National
Authors: Blaeser Susan B. , Schomer Paul D.
Published: July 2012

American National Standards (ANSI Standards) developed by Accredited Standards Committees S1, S2, S3, and S12 in the areas of acoustics, mechanical vibration and shock, bioacoustics, and noise, respectively, are published by the Acoustical Society of America (ASA). In addition to these standards, ASA publishes catalogs of Acoustical Standards, both National and International. To receive copies of the latest Standards catalogs, please contact Susan B. Blaeser.

Comments are welcomed on all material in Acoustical Standards News.

This Acoustical Standards News section in JASA, as well as the National and International Catalogs of Acoustical Standards, and other information on the Standards Program of the Acoustical Society of America, are available via the ASA home page: http://acousticalsociety.org.
Deep Brain Stimulation for Psychiatric Disease: Contributions and Validity of Animal Models
Authors: Hamani Clement , Temel Yasin
Published: July 2012

Investigations in animal models can help to understand and improve deep brain stimulation treatments for neuropsychiatric disease.
Focusing In on Virus Inactivation
Authors: Obhrai Jagdeep S.
Published: July 2012

A new virus inactivation strategy that retains immunogenicity may improve vaccine development.
Appreciating Staph Support
Authors: Shrout Joshua D.
Published: July 2012

Staphlyococcus aureus
synthesizes two related peptides with divergent functions as an antimicrobial agent and a biofilm-promoting scaffold.
Getting to the Root of SLOS
Authors: Skarke Carsten
Published: July 2012

Smith-Lemli-Opitz syndrome is associated with increased oxidative stress and lipid peroxidation.
Too Much of a Good Thing: Hyperoxia and Lung Injury
Authors: Zeki Amir A.
Published: July 2012

High oxygen levels during mechanical ventilation can lead to significant lung injury via alterations in alveolar cell structure and function.
Complete Genome Sequence of the Genotype 4 Hepatitis E Virus Strain Prevalent in Swine in Jiangsu Province, China, Reveals a Close Relationship with That from the Human Population in This Area
Authors: Wang Hua , He Yilin , Shen Quan , Wang Xiaochun , Yang Shixing , Cui Li , Ren Liping , Sun Guangming , Hua Xiuguo , Shao Shihe , Zhang Wen
Published: July 2012

Hepatitis E virus (HEV) is a zoonotic pathogen of which several species of animal were reported as reservoirs. Swine stands out as the major reservoir for HEV infection in humans, as suggested by the close genetic relationship of swine and human viruses. In a previous study, we sequenced the complete genome of a human genotype 4 HEV strain (HM439284) that is prevalent in Jiangsu Province, China. Here we report the complete genome of one genotype 4 HEV strain which is prevalent in swine herds in Jiangsu Province. Phylogenetic analysis indicated that the swine HEV strain in the present study has high sequence homology (>92%) with the genotype 4 HEV strains prevalent in the human population of Jiangsu Province. These results suggested that the genotype 4 HEV strain in the present study is involved in cross-species transmission between swine and humans in this area.
Complete Genome Sequence of Bluetongue Virus Serotype 9: Implications for Serotyping
Authors: Rao Pavuluri Panduranga , Reddy Yella Narasimha , Hegde Nagendra R.
Published: July 2012

The second complete genome of bluetongue virus serotype 9 (BTV-9) is presented in this report. The sequence analysis points to continued circulation in India of a mixed topotype virus apparently belonging to the BTV-9 serotype, and it raises questions about approaches for serotyping bluetongue viruses.
PanM, an Acetyl-Coenzyme A Sensor Required for Maturation of
l
-Aspartate Decarboxylase (PanD)
Authors: Stuecker Tara N. , Tucker Alex C. , Escalante-Semerena Jorge C.
Published: July 2012

Coenzyme A (CoA) is essential for cellular chemistry in all forms of life. The pantothenate moiety of CoA is generated from the condensation of pantoate and β-alanine. β-Alanine is formed by decarboxylation of
l
-aspartate catalyzed by PanD, a pyruvoyl enzyme that is synthesized by the cell as an inactive precursor (pro-PanD). Maturation of pro-PanD into PanD occurs via a self-cleavage event at residue Ser25, which forms the catalytic pyruvoyl moiety. We recently reported that
Salmonella enterica
PanM was necessary for pro-PanD maturation, both
in vitro
and
in vivo
. Notably, PanM is annotated as a Gcn5-like
N
-acetyltransferase (GNAT), which suggested that lysine acetylation might be part of the mechanism of maturation. Here we show that PanM lacks acetyltransferase activity and that acetyl-CoA stimulates its activity. Results of experiments with nonhydrolyzable ethyl-CoA and genetically encoded acetyl-lysine-containing PanD support the conclusion that PanM-dependent pro-PanD maturation does not involve an acetyl transfer event. We also show that CoA binding to PanM is needed for
in vivo
activity and that disruption of CoA binding prevents PanM from interacting with PanD. We conclude that PanM is a GNAT homologue that lost its acetyltransferase activity and evolved a new function as an acetyl-CoA sensor that can trigger the maturation of pro-PanD.

IMPORTANCE
Nε-lysine acetylation is increasingly being recognized as a widespread and important form of posttranslational regulation in bacteria. The acetyltransferases that catalyze these reactions are poorly characterized in bacteria. Based on annotation, most bacterial genomes contain several acetyltransferases, but the physiological roles of only a handful have been determined. Notably, a subset of putative acetyltransferases lack residues that are critical for activity in most biochemically characterized acetyltransferases. We show that one such putative acetyltransferase, PanM (formerly YhhK), lacks acetyltransferase activity but functions instead as an acetyl-coenzyme A (CoA) sensor. This work establishes the possibility that, like PanM, other putative acetyltransferases may have evolved new functions while retaining the ability to sense acetyl-CoA.
The impact of a novel franchise clinic network on access to medicines and vaccinations in Kenya: a cross-sectional study
Authors: Berk Justin , Adhvaryu Achyuta
Published: July 2012

Objectives

To study the impact of a new franchise health clinic model (The HealthStore Foundation's CFWShops) on access to vaccinations and treatment for acute illnesses in a nationally representative sample of children in Kenya.

Design

The authors used multivariate linear and count regressions to examine associations between receipt of vaccinations or treatment and proximity to a franchise health clinic, adjusting for individual, household and clinic attributes as well as region fixed effects.

Setting

Demographic and Health Survey data from Kenya, 2008–2009.

Participants

6079 Kenyan children younger than 5 years, of whom 2310 reported recent acute illness.

Main outcome measures

Outcomes for all children were number of polio doses received, number of DPT doses received, receipt of BCG vaccine, receipt of measles vaccine and number of total vaccinations received. Outcomes for acutely ill children were receipt of any medical treatment, treatment for fever, treatment for malaria and treatments specifically stocked by CFWShops.

Results

Children living within 30 km of a CFWShop received 0.129 (p=0.017) and 0.113 (p=0.025) more DPT and polio doses, respectively; and 0.285 more total vaccinations (p=0.023). Among acutely ill children, CFWShop proximity was associated with significant increases in the probabilities of receiving any medical treatment (0.142; p<0.001), treatment for fever (0.117; p=0.007) and treatments specifically stocked by CFWShops (0.064; p=0.015). Use of CFWShop services was not significantly different for lower-income vis-a-vis higher-income households.

Conclusions

The franchise health clinic model could substantially increase access to essential vaccinations and treatments in low-income countries. Moreover, the model's benefits may accrue to lesser- and higher-income households alike.
Long-term follow-up of cortisol awakening response in patients treated for stress-related exhaustion
Authors: Sjörs Anna , Ljung Thomas , Jonsdottir Ingibjörg H
Published: July 2012

Objectives

Studies on hypothalamus–pituitary–adrenal (HPA) axis activity in stress-related exhaustion and burnout have revealed incongruent results, and few longitudinal studies on clinical populations have been performed. This study was designed to investigate differences in HPA axis activity between patients with stress-related exhaustion and healthy controls and to investigate longitudinal changes in HPA axis activity in the patient group as they entered a multimodal treatment programme.

Design

HPA axis activity was assessed through the cortisol awakening response (CAR). Salivary cortisol was sampled at awakening and after 15 min. Follow-up measurements were performed in the patient group after 3, 6, 12 and 18 months.

Setting

An outpatient clinic specialising in stress-related illness.

Participants

Patients with clinically diagnosed stress-related exhaustion (n=162) and healthy controls (n=79).

Primary and secondary outcome measures

The primary measure was CAR measured as the difference between the two salivary cortisol samples. Changes in CAR during follow-up were related to changes in symptoms of burnout, depression and anxiety.

Results

Patients showed similar CAR as the controls and their CAR did not change significantly during treatment. No association was found between CAR and symptom development during treatment.

Conclusions

The authors conclude that CAR does not seem to discriminate clinically defined patients with exhaustion from healthy controls and it appears not to change during treatment. CAR, measured as salivary cortisol, at awakening and after 15 min, is thus not a valid marker for stress-related exhaustion.
Return to pre-injury health status and function 12 months after hospitalisation for sport and active recreation related orthopaedic injury
Authors: Andrew Nadine Elizabeth , Wolfe Rory , Cameron Peter , Richardson Martin , Page Richard , Bucknill Andrew , Gabbe Belinda J
Published: July 2012

Background

Hospitalised sport and active recreation injuries can have serious long-term consequences. Despite this, few studies have examined the long-term outcomes of these injuries. The purpose of this study was to establish whether patients hospitalised with orthopaedic sport and active recreation injuries, have returned to their pre-injury levels of health status and function, 12 months post injury and identify factors associated with poor outcomes. The present work was a cohort study with retrospective assessment of pre-injury status and prospective assessment of outcome at 12 months post injury.

Methods

Adults with orthopaedic sport and active recreation injuries, captured by the Victorian Orthopaedic Trauma Outcomes Registry were recruited to the study. Pre-injury and 12-month outcomes were assessed using the 36-item Short Form Health Survey (SF-36) and the extended Glasgow Outcome Scale. Differences in pre-injury and post-injury SF-36 scores were examined and demographic, injury, hospital and physical activity variables were assessed for associations with outcome using multivariate linear regression.

Results

Of the 324 participants 98% were followed-up at 12 months post injury. At 12 months, participants reported a mean 7.0-point reduction in physical health (95% CI 5.8 to 7.8) and a 2.5-point reduction in mental health (95% CI 1.2 to 3.0), with 58% (95% CI 52.6% to 63.4%) reporting reduced function. Sporting group (p=0.001), Injury Severity Score >15 (p=0.007) and high pre-injury vigorous activity levels (p=0.04), were related to poorer physical health outcomes.

Conclusions

At 12 months post injury, most participants reported large reductions in physical health and reduced function. This information is important for furthering our understanding of the burden of sport and active recreation injury and setting priorities for treatment and rehabilitation.
The investigation and management of hirsutism
Authors: Franks Stephen
Published: July 2012

Excess male-pattern body hair in women is a very common and psychologically damaging condition. Although its cause is usually a chronic and benign disorder (most commonly polycystic ovary syndrome) it may rarely be an indication of a more serious endocrine disease such as Cushing syndrome or an androgen-secreting tumour. Investigations do not usually need to be extensive, but effective management is important, irrespective of cause, for what can be a debilitating symptom. Specific treatment of any underlying disease is important but in most cases treatment is empirical; it may simply involve physical hair removal, ideally by electrolysis or laser treatment. However, endocrine therapy to suppress androgen production and/or action is desirable in many, if not most, cases.
EXACT TRANSIENT VIBRATION OF NONUNIFORM BARS, SHAFTS AND STRINGS GOVERNED BY WAVE EQUATIONS
Authors: YANG B. , NOH K.
Published: July 2012

A new analytical method is developed for transient solutions for bars in longitudinal vibration, shafts in torsional vibration and strings in transverse vibration. These vibrating continua have nonuniform distributions of geometric and material properties, and are governed by second-order partial differential equations (wave equations). Based on a transfer function formulation and a residue formula, the proposed method delivers exact solutions for several types of nonuniform systems subject to external, boundary and initial disturbances. The proposed method does not need system eigenfunctions, and is numerically efficient as it only involves simple operations of two-by-two matrices.
AN ANALYTIC APPROACH FOR EXACTLY DETERMINING CRITICAL LOADS OF BUCKLING OF NONUNIFORM COLUMNS
Authors: HUANG Y. , LI X.-F.
Published: July 2012

This paper studies buckling instability of columns with variable bending stiffness subjected to an axially compressive load. An analytic approach has been presented to determine critical buckling loads of a nonuniform column with or without continuous elastic restraint along its length. We transform this problem into a Fredholm equation, and then to a system of linear equations. The desired buckling loads can be easily obtained by solving the least positive eigenvalue of the resulting system. The validity and efficiency of the method is confirmed by comparing our numerical results with those available. The influences of variable cross-section or elastic restraint stiffness on the buckling loads of a simply-supported column are analyzed. A suboptimal design of a tapered cylindrical bar with fixed weight is given. The present results are of benefit to the optimal design of beam/column structures.
NUMERICAL AND EXPERIMENTAL STUDY OF BUCKLING OF ADVANCED FIBER COMPOSITE CYLINDERS UNDER AXIAL COMPRESSION
Authors: PRIYADARSINI R. S. , KALYANARAMAN V. , SRINIVASAN S. M.
Published: July 2012

Advanced lightweight laminated composite shells are increasingly being used in modern aerospace structures, for enhancing their structural efficiency and performance. Such thin-walled structures are susceptible to buckling when subjected to static and dynamic compressive stresses. In this paper, details of a numerical (FEM) and an experimental study on buckling of carbon fiber reinforced plastics (CFRP) layered composite cylinders under displacement and load controlled static and dynamic axial compression are reported. The effects of different types of loadings, geometric properties, lamina lay-up and amplitudes of imperfection on the strength of the cylinders under compression are studied. Accurate measurement of imperfections in the cylindrical surface is carried out in the specimens tested. It is shown that the buckling behavior of thin composite cylindrical shells can be evaluated accurately by modeling measured imperfections and material properties in FEM.
BUCKLING ANALYSIS OF TAPERED COMPOSITE PLATES USING RITZ METHOD BASED ON FIRST-ORDER SHEAR DEFORMATION THEORY
Authors: AKHLAQUE-E-RASUL SHAIKH , GANESAN RAJAMOHAN
Published: July 2012

Tapered composite plates have various engineering applications such as helicopter yoke, robot arms and turbine blades in which the structure needs to be stiff at one end and flexible at another end. No closed form analytical solution of tapered composite plates using Ritz method based on first-order shear deformation theory (FSDT) is available at present. In the present paper, the buckling analysis of different types of composite plates with longitudinal-internal-ply-drop-off configuration is investigated using Ritz method. The buckling analysis of these plates is also conducted using ANSYS®. The efficiency and accuracy of the developed formulation are established in comparison with available solutions, where applicable. A detailed parametric study has been conducted on various taper and lay-up configurations, all made of NCT/301 graphite-epoxy, in order to investigate the effects of taper angle, length-to-height ratio, length-to-width ratio, boundary conditions, and taper and lay-up configurations.
EFFECT OF ELECTRON-ELECTRON INTERACTION NEAR THE METAL-INSULATOR TRANSITION IN DOPED SEMICONDUCTORS STUDIED WITHIN THE LOCAL DENSITY APPROXIMATION
Authors: HARASHIMA YOSUKE , SLEVIN KEITH
Published: July 2012

We report a numerical analysis of Anderson localization in a model of a doped semiconductor. The model incorporates the disorder arising from the random spatial distribution of the donor impurities and takes account of the electron-electron interactions between the carriers using density functional theory in the local density approximation. Preliminary results suggest that the model exhibits a metal-insulator transition.
CAN DIFFUSION MODEL LOCALIZATION IN OPEN MEDIA?
Authors: TIAN CHU-SHUN , CHEUNG SAI-KIT , ZHANG ZHAO-QING
Published: July 2012

We employed a first-principles theory – the supersymmetric field theory – formulated for wave transport in very general open media to study static transport of waves in quasi-one-dimensional localized samples. We predicted analytically and confirmed numerically that in these systems, localized waves display an unconventional diffusive phenomenon. Different from the prevailing self-consistent local diffusion model, our theory is capable of capturing all disorder-induced resonant transmissions, which give rise to significant enhancement of local diffusion inside a localized sample. Our theory should be able to be generalized to two- and three-dimensional open media, and open a new direction in the study of Anderson localization in open media.
CRITICAL EXPONENT FOR THE QUANTUM SPIN HALL TRANSITION IN ℤ2 NETWORK MODEL
Authors: KOBAYASHI K. , OHTSUKI T. , SLEVIN K.
Published: July 2012

We have estimated the critical exponent describing the divergence of the localization length at the metal-quantum spin Hall insulator transition. The critical exponent for the metal-ordinary insulator transition in quantum spin Hall systems is known to be consistent with that of topologically trivial symplectic systems. However, the precise estimation of the critical exponent for the metal-quantum spin Hall insulator transition proved to be problematic because of the existence, in this case, of edge states in the localized phase. We have overcome this difficulty by analyzing the second smallest positive Lyapunov exponent instead of the smallest positive Lyapunov exponent. We find a value for the critical exponent ν = 2.73 ± 0.02 that is consistent with that for topologically trivial symplectic systems.
A COMPARISON OF HARMONIC CONFINEMENT AND DISORDER IN INDUCING LOCALIZATION EFFECTS IN A SUPERCONDUCTOR
Authors: DEY POULUMI , KHAN AYAN , BASU SAURABH , TANATAR B.
Published: July 2012

We present a comparative study of the localization effects induced by harmonic trapping and random onsite disorder in a 2D s-wave superconductor. Performing a numeric computation of the Bogoliubov-de Gennes equations in the presence of parabolic trap and random disorder, we obtain the eigensolutions as a function of trap depth and disorder strength. While the wavefunctions demonstrate localization tendencies for moderate disorder strengths, with finally yielding an insulating behavior at large disorder, the harmonic confinement effects are seen to be vastly more drastic in inducing localization effects.
ENHANCEMENT OF GRAPHENE BINDING ENERGY BY Ti 1ML INTERCALATION BETWEEN GRAPHENE AND METAL SURFACES
Authors: KANEKO TOMOAKI , IMAMURA HIROSHI
Published: July 2012

We theoretically investigate the effects of intercalation of a thin Ti layer between graphene (Gr) and metal surface ( Au , Ag , Al , Pt , and Pd ) on structural and electronic properties by using the first-principles total energy calculations. We find that the strongest binding energy is realized when 1 monolayer (ML) of Ti is intercalated between Gr and a metal surface independent of the metal atoms, which is 0.08-0.15 eV larger than that for Gr absorbed on a Ti (0001) surface. As the number of Ti layers increases, the binding energy monotonically decreases and converges to that for Gr adsorbed onto the Ti surface. We show that the origin of the enhancement of binding energy can be classified into two classes by considering the affinity of Ti for the metal surfaces.
GENERALIZATION OF CHIRAL SYMMETRY FOR TILTED DIRAC CONES
Authors: KAWARABAYASHI TOHRU , HATSUGAI YASUHIRO , MORIMOTO TAKAHIRO , AOKI HIDEO
Published: July 2012

The notion of chiral symmetry for the conventional Dirac cone is generalized to include the tilted Dirac cones, where the generalized chiral operator turns out to be non-hermitian. It is shown that the generalized chiral symmetry generically protects the zero modes (n = 0 Landau level) of the Dirac cone even when tilted. The present generalized symmetry is equivalent to the condition that the Dirac Hamiltonian is elliptic as a differential operator, which provides an explicit relevance to the index theorem.
ELECTRONIC STATES AND LOCAL DENSITY OF STATES NEAR GRAPHENE CORNER EDGE
Authors: SHIMOMURA YUJI , TAKANE YOSITAKE , WAKABAYASHI KATSUNORI
Published: July 2012

We study that stability of edge localized states in semi-infinite graphene with a corner edge of the angles 60°, 90°, 120° and 150°. We adopt a nearest-neighbor tight-binding model to calculate the local density of states (LDOS) near each corner edge using Haydock's recursion method. The results of the LDOS indicate that the edge localized states stably exist near the 60°, 90°, and 150° corner, but locally disappear near the 120° corner. By constructing wave functions for a graphene ribbon with three 120° corners, we show that the local disappearance of the LDOS is caused by destructive interference of edge states and evanescent waves.
ANALYSIS OF QUANTUM CORRECTIONS TO CONDUCTIVITY AND THERMOPOWER IN GRAPHENE — NUMERICAL AND ANALYTICAL APPROACHES
Authors: HINZ ALEKSANDER P. , KETTEMANN STEFAN , MUCCIOLO EDUARDO R.
Published: July 2012

We present numerical and analytical studies of the crossover between weak antilocalization and weak localization in monolayer graphene and their influence on thermopower. By the use of the recursive Green's function method, we find that these quantum corrections result in an enhancement of thermopower, which can be observed in the resulting magnetic field dependence. This magneto thermopower strongly depends on the size and strength of the impurities as well as on the back gate voltage of the system and the impurity concentration. We show in detail the crossover of these localization effects with these parameters. Using the disorder parameters of the numerical calculation, we find quantitative agreement with the analytical calculations.
THE SPIN GLASS-KONDO COMPETITION IN DISORDERED CERIUM SYSTEMS
Authors: MAGALHAES S. G , ZIMMER F. , COQBLIN B.
Published: July 2012

We discuss the competition between the Kondo effect, the spin glass state and a magnetic order observed in disordered Cerium systems. We present firstly the experimental situation of disordered alloys such as CeNi1-xCux and then the different theoretical approaches based on the Kondo lattice model, with different descriptions of the intersite exchange interaction for the spin glass. After the gaussian approach of the Sherrington-Kirkpatrick model, we discuss the Mattis and the van Hemmen models. Then, we present simple cluster calculations in order to describe the percolative evolution of the clusters from the cluster spin glass to the inhomogeneous ferromagnetic order recently observed in CeNi1-xCux disordered alloys and finally we discuss the effect of random and transverse magnetic field.
Temporal and palaeoenvironmental distribution of manus- and pes-dominated sauropod trackways
Authors: Falkingham P. L. , Bates K. T. , Mannion P. D.
Published: July 2012

Fossil tracks are a source of information about extinct animals that can supplement the osteological record, yet they are often overlooked in macroevolutionary studies. The substrates in which tracks are preserved are indicative of palaeoenvironment and habitat, and track morphology can be linked to the motion and loading of the limb. Sauropod dinosaurs represent the largest terrestrial animals ever to have existed, and the evolution of their body plan had direct consequences for their locomotion and subsequent morphology of their tracks. Here we show that the relative proportions of manus- and pes-dominated sauropod trackways appears to remain constant in the Jurassic and Cretaceous despite an apparent evolutionary anterior shift of centre of mass seen in the body fossil record. However, in Cretaceous rocks, manus-dominated tracks are most commonly recorded in cohesive substrates (e.g. mudstones), whereas pes-dominated tracks tend to be restricted to non-cohesive substrates (e.g. sandstones). This bias is not present in the Jurassic, and therefore may be the result of niche partitioning among sauropods associated with the Cretaceous diversification of the anatomically and environmentally specialized titanosaurs. In this respect, the ichnological record appears to provide complementary evidence to the osteological record and suggests a causative link between locomotion, ecology, and macroevolution in sauropod dinosaurs.

Supplementary material:

The complete dataset of occurrences of MDTs and PDTs is available at
http://www.geolsoc.org.uk/SUP18530
.