bluuebunny/crossref_metadata_2025 huggingface dataset:
Oral Poliovirus Vaccine Evolution and Insights Relevant to Modeling the Risks of Circulating Vaccine‐Derived Polioviruses (cVDPVs)
Authors: Duintjer Tebbens Radboud J. , Pallansch Mark A. , Kim Jong‐Hoon , Burns Cara C. , Kew Olen M. , Oberste M. Steven , Diop Ousmane M. , Wassilak Steven G.F. , Cochi Stephen L. , Thompson Kimberly M.
Published: March 2013

The live, attenuated oral poliovirus vaccine (OPV) provides a powerful tool for controlling and stopping the transmission of wild polioviruses (WPVs), although the risks of vaccine‐associated paralytic polio (VAPP) and circulating vaccine‐derived poliovirus (cVDPV) outbreaks exist as long as OPV remains in use. Understanding the dynamics of cVDPV emergence and outbreaks as a function of population immunity and other risk factors may help to improve risk management and the development of strategies to respond to possible outbreaks. We performed a comprehensive review of the literature related to the process of OPV evolution and information available from actual experiences with cVDPV outbreaks. Only a relatively small fraction of poliovirus infections cause symptoms, which makes direct observation of the trajectory of OPV evolution within a population impractical and leads to significant uncertainty. Despite a large global surveillance system, the existing genetic sequence data largely provide information about transmitted virulent polioviruses that caused acute flaccid paralysis, and essentially no data track the changes that occur in OPV sequences as the viruses transmit largely asymptomatically through real populations with suboptimal immunity. We updated estimates of cVDPV risks based on actual experiences and identified the many limitations in the existing data on poliovirus transmission and immunity and OPV virus evolution that complicate modeling. Modelers should explore the space of potential model formulations and inputs consistent with the available evidence and future studies should seek to improve our understanding of the OPV virus evolution process to provide better information for policymakers working to manage cVDPV risks.
Health Risk Characterization of Chlorpyrifos Using Epidemiological Dose‐Response Data and Probabilistic Techniques: A Case Study with Rice Farmers in Vietnam
Authors: Phung Dung Tri , Connell Des , Yu Qiming , Chu Cordia
Published: March 2013

Various methods for risk characterization have been developed using probabilistic approaches. Data on Vietnamese farmers are available for the comparison of outcomes for risk characterization using different probabilistic methods. This article addresses the health risk characterization of chlorpyrifos using epidemiological dose‐response data and probabilistic techniques obtained from a case study with rice farmers in Vietnam. Urine samples were collected from farmers and analyzed for trichloropyridinol (TCP), which was converted into absorbed daily dose of chlorpyrifos. Adverse health response doses due to chlorpyrifos exposure were collected from epidemiological studies to develop dose‐adverse health response relationships. The health risk of chlorpyrifos was quantified using hazard quotient (HQ), Monte Carlo simulation (MCS), and overall risk probability (ORP) methods. With baseline (prior to pesticide spraying) and lifetime exposure levels (over a lifetime of pesticide spraying events), the HQ ranged from 0.06 to 7.1. The MCS method indicated less than 0.05% of the population would be affected while the ORP method indicated that less than 1.5% of the population would be adversely affected. With postapplication exposure levels, the HQ ranged from 1 to 32.5. The risk calculated by the MCS method was that 29% of the population would be affected, and the risk calculated by ORP method was 33%. The MCS and ORP methods have advantages in risk characterization due to use of the full distribution of data exposure as well as dose response, whereas HQ methods only used the exposure data distribution. These evaluations indicated that single‐event spraying is likely to have adverse effects on Vietnamese rice farmers.
HOW LARGE IS THE PRIVATE SECTOR IN AFRICA? EVIDENCE FROM NATIONAL ACCOUNTS AND LABOUR MARKETS
Authors: STAMPINI MARCO , LEUNG RON , DIARRA SETOU M. , PLA LAURÉLINE
Published: March 2013

In recent years, the private sector has been recognised as a key engine of Africa's economic development. Yet, very little is known about its size and characteristics. We present novel estimates for 50 African countries and show that the private sector accounts for about two thirds of total investments, four fifths of total consumption and three fourths of total credit. Countries with small private sectors include a sample of oil exporters and some of the poorest countries in the continent. Surprisingly, the size of the private sector does not appear to be significantly correlated with growth performance. Labour market data reinforce the idea of a large private sector, which provides about 90% of total employment opportunities. However, most of this labour is informal and characterised by low productivity: permanent wage jobs in the private sector account on average for only 10% of total employment. South Africa is the notable exception, with formal wage employment in the private sector representing 46% of total employment. Finally, we find evidence of negative private sector earning premiums (−13% on the average), suggesting that market distortions abound. These are likely to prevent the efficient allocation of human resources and to reduce the overall productivity of the African economies.
Role of nucleation in cortical microtubule array organization: variations on a theme
Authors: Fishel Erica A. , Dixit Ram
Published: March 2013

The interphase cortical microtubules (CMTs) of plant cells form strikingly ordered arrays in the absence of a dedicated microtubule‐organizing center. Considerable research effort has focused on activities such as bundling and severing that occur after CMT nucleation and are thought to be important for generating and maintaining ordered arrays. In this review, we focus on how nucleation affects CMT array organization. The bulk of CMTs are initiated from γ–tubulin‐containing nucleation complexes localized to the lateral walls of pre‐existing CMTs. These CMTs grow either at an acute angle or parallel to the pre‐existing CMT. Although the impact of microtubule‐dependent nucleation is not fully understood, recent genetic, live‐cell imaging and computer simulation studies have demonstrated that the location, timing and geometry of CMT nucleation have a considerable impact on the organization and orientation of the CMT array. These nucleation properties are defined by the composition, position and dynamics of γ–tubulin‐containing nucleation complexes, which represent control points for the cell to regulate CMT array organization.
Overexpression of Caveolin‐1 Is Sufficient to Phenocopy the Behavior of a Disease‐Associated Mutant
Authors: Hanson Caroline A. , Drake Kimberly R. , Baird Michelle A. , Han Bing , Kraft Lewis J. , Davidson Michael W. , Kenworthy Anne K.
Published: March 2013

Mutations and alterations in caveolin‐1 expression levels have been linked to a number of human diseases. How misregulation of caveolin‐1 contributes to disease is not fully understood, but has been proposed to involve the intracellular accumulation of mutant forms of the protein. To better understand the molecular basis for trafficking defects that trap caveolin‐1 intracellularly, we compared the properties of a GFP‐tagged version of caveolin‐1 P132L, a mutant form of caveolin‐1 previously linked to breast cancer, with wild‐type caveolin‐1. Unexpectedly, wild‐type caveolin‐1‐GFP also accumulated intracellularly, leading us to examine the mechanisms underlying the abnormal localization of the wild type and mutant protein in more detail. We show that both the nature of the tag and cellular context impact the subcellular distribution of caveolin‐1, demonstrate that even the wild‐type form of caveolin‐1 can function as a dominant negative under some conditions, and identify specific conformation changes associated with incorrectly targeted forms of the protein. In addition, we find intracellular caveolin‐1 is phosphorylated on Tyr14, but phosphorylation is not required for mistrafficking of the protein. These findings identify novel properties of mistargeted forms of caveolin‐1 and raise the possibility that common trafficking defects underlie diseases associated with overexpression and mutations in caveolin‐1.
Comparison of three different sampling methods for canine skin lipids
Authors: Angelbeck‐Schulze Mandy , Stahl Jessica , Brodesser Susanne , Rohn Karl , Naim Hassan , Hewicker‐Trautwein Marion , Kietzmann Manfred , Bäumer Wolfgang , Mischke Reinhard
Published: March 2013

Background

Epidermal lipids are of major interest in dermatological research, especially in canine atopic dermatitis. Owing to the existence of several sampling methods, the interpretation of study results is often complicated.

Objectives

This study aimed to compare three different sampling methods and to establish a minimally invasive method for collecting canine epidermal lipids.

Animals and methods

Skin samples from five dogs with no obvious skin abnormalities were taken from the caudal back and the inguinal region postmortem. Samples consisted of heat‐separated epidermis of three skin biopsies, three scrapes and three skin scrubs. Lipids were analysed by high‐performance thin‐layer chromatography; the resulting bands were identified by using corresponding standards, retardation factors and mass spectrometry. The influences of the sampling method, the body site and the ceramide standards were investigated.

Results

Between body sites, significant differences were found for cholesterol sulphate, cholesteryl esters and triglycerides. Significant differences between sampling methods were detected for all lipid fractions except for cholesterol sulphate and glucosylceramides within the lipid profile, and for at least four ceramide classes within the ceramide profile. The most obvious discrepancies were found between heat‐separated epidermis and skin scrub. The reproducibility was high for scraping and skin scrub, but was lowest for heat‐separated epidermis. Furthermore, this study revealed a marked influence of ceramide standards on the results regarding the ceramide profile.

Conclusions and clinical importance

Scraping and skin scrub are comparably suitable methods for skin lipid sampling, whereas the analysis of heat‐separated epidermis may not be the method of first choice.
Evidence‐based step‐wise approach to managing chronic kidney disease in dogs and cats
Authors: Polzin David J.
Published: March 2013

Objective

To provide a framework for successfully managing chronic kidney disease (CKD) over an extended period of time with the goal of optimizing clinical outcomes by fostering a veterinarian‐client relationship that facilitates successful application of evidence‐based treatment.

Etiology

Ultimately, CKD results from loss of functional nephrons; however, the specific disease process responsible for this loss usually cannot be determined due to development of chronic changes (eg, fibrosis) and compensatory adaptations that have occurred in the kidneys of patients with CKD. Earlier diagnosis may foster a better understanding of the etiologies of CKD.

Diagnosis

Diagnosis of CKD is based on establishing loss of kidney function(s) due to primary kidney disease that have been present for an extended time (typically 3 months or longer).

Therapy

The goals of therapy are to: (1) slow progressive loss of kidney function, (2) ameliorate clinical and biochemical consequences of CKD, and (3) maintain adequate nutrition. These goals are achieved by: (1) managing adaptive processes that promote progression of CKD, (2) controlling intake of water, nutrients, minerals and electrolytes, and (3) correcting hormonal deficiencies.

Prognosis

The short‐term prognosis for dogs with CKD varies from good to poor, while the long‐term prognosis for dogs with CKD is generally guarded to poor depending on the International Renal Interest Society (IRIS) CKD stage of the patient. Both short‐term and long‐term prognosis for cats with CKD may vary from good to poor depending on the IRIS CKD stage. However, prognosis is more variable and unpredictable in cats.
Acoustic attenuation, phase and group velocities in liquid-filled pipes III: Nonaxisymmetric propagation and circumferential modes in lossless conditions
Authors: Baik Kyungmin , Jiang Jian , Leighton Timothy G.
Published: March 2013

Equations for the nonaxisymmetric modes that are axially and circumferentially propagating in a liquid-filled tube with elastic walls surrounded by air/vacuum are presented using exact elasticity theory. Dispersion curves for the axially propagating modes are obtained and verified through comparison with measurements. The resulting theory is applied to the circumferential modes, and the pressures and the stresses in the liquid-filled pipe are calculated under external forced oscillation by an acoustic source. This provides the theoretical foundation for the narrow band acoustic bubble detector that was subsequently deployed at the Target Test Facility (TTF) of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL), TN.
Stabilization of time domain acoustic boundary element method for the exterior problem avoiding the nonuniqueness
Authors: Jang Hae-Won , Ih Jeong-Guon
Published: March 2013

The time domain boundary element method (TBEM) to calculate the exterior sound field using the Kirchhoff integral has difficulties in non-uniqueness and exponential divergence. In this work, a method to stabilize TBEM calculation for the exterior problem is suggested. The time domain CHIEF (Combined Helmholtz Integral Equation Formulation) method is newly formulated to suppress low order fictitious internal modes. This method constrains the surface Kirchhoff integral by forcing the pressures at the additional interior points to be zero when the shortest retarded time between boundary nodes and an interior point elapses. However, even after using the CHIEF method, the TBEM calculation suffers the exponential divergence due to the remaining unstable high order fictitious modes at frequencies higher than the frequency limit of the boundary element model. For complete stabilization, such troublesome modes are selectively adjusted by projecting the time response onto the eigenspace. In a test example for a transiently pulsating sphere, the final average error norm of the stabilized response compared to the analytic solution is 2.5%.
Effective beam pattern of the Blainville's beaked whale (Mesoplodon densirostris) and implications for passive acoustic monitoring
Authors: Shaffer Jessica Ward , Moretti David , Jarvis Susan , Tyack Peter , Johnson Mark
Published: March 2013

The presence of beaked whales in mass-strandings coincident with navy maneuvers has prompted the development of methods to detect these cryptic animals. Blainville's beaked whales, Mesoplodon densirostris, produce distinctive echolocation clicks during long foraging dives making passive acoustic detection a possibility. However, performance of passive acoustic monitoring depends upon the source level, beam pattern, and clicking behavior of the whales. In this study, clicks recorded from Digital acoustic Tags (DTags) attached to four M. densirostris were linked to simultaneous recordings from an 82-hydrophone bottom-mounted array to derive the source level and beam pattern of the clicks, as steps towards estimating their detectability. The mean estimated on-axis apparent source level for the four whales was 201 dBrms97. The mean 3 dB beamwidth and directivity index, estimated from sequences of clicks directed towards the far-field hydrophones, were 13° and 23 dB, respectively. While searching for prey, Blainville's beaked whales scan their heads horizontally at a mean rate of 3.6°/s over an angular range of some +/−10°. Thus, while the DI indicates a narrow beam, the area of ensonification over a complete foraging dive is large given the combined effects of body and head movements associated with foraging.
Proper formulation of viscous dissipation for nonlinear waves in solids
Authors: Destrade Michel , Saccomandi Giuseppe , Vianello Maurizio
Published: March 2013

To model nonlinear viscous dissipative motions in solids, acoustical physicists usually add terms linear in Ė, the material time derivative of the Lagrangian strain tensor E, to the elastic stress tensor σ derived from the expansion to the third (sometimes fourth) order of the strain energy density E=E(tr E,tr E2,tr E3). Here it is shown that this practice, which has been widely used in the past three decades or so, is physically wrong for at least two reasons and that it should be corrected. One reason is that the elastic stress tensor σ is not symmetric while Ė is symmetric, so that motions for which σ+σT≠0 will give rise to elastic stresses that have no viscous pendant. Another reason is that Ė is frame-invariant, while σ is not, so that an observer transformation would alter the elastic part of the total stress differently than it would alter the dissipative part, thereby violating the fundamental principle of material frame indifference. These problems can have serious consequences for nonlinear shear wave propagation in soft solids as seen here with an example of a kink in almost incompressible soft solids.
The anisotropic hyperelastic biomechanical response of the vocal ligament and implications for frequency regulation: A case study
Authors: Kelleher Jordan E. , Siegmund Thomas , Du Mindy , Naseri Elhum , Chan Roger W.
Published: March 2013

One of the primary mechanisms to vary one's vocal frequency is through vocal fold length changes. As stress and deformation are linked to each other, it is hypothesized that the anisotropy in the biomechanical properties of the vocal fold tissue would affect the phonation characteristics. A biomechanical model of vibrational frequency rise during vocal fold elongation is developed which combines an advanced biomechanical characterization protocol of the vocal fold tissue with continuum beam models. Biomechanical response of the tissue is related to a microstructurally informed, anisotropic, nonlinear hyperelastic constitutive model. A microstructural characteristic (the dispersion of collagen) was represented through a statistical orientation function acquired from a second harmonic generation image of the vocal ligament. Continuum models of vibration were constructed based upon Euler–Bernoulli and Timoshenko beam theories, and applied to the study of the vibration of a vocal ligament specimen. From the natural frequency predictions in dependence of elongation, two competing processes in frequency control emerged, i.e., the applied tension raises the frequency while simultaneously shear deformation lowers the frequency. Shear becomes much more substantial at higher modes of vibration and for highly anisotropic tissues. The analysis was developed as a case study based on a human vocal ligament specimen.
The inverse problem of acoustic wave scattering by an air-saturated poroelastic cylinder
Authors: Ogam Erick , Fellah Z. E. A , Baki Paul
Published: March 2013

The efficient use of plastic foams in a diverse range of structural applications like in noise reduction, cushioning, and sleeping mattresses requires detailed characterization of their permeability and deformation (load-bearing) behavior. The elastic moduli and airflow resistance properties of foams are often measured using two separate techniques, one employing mechanical vibration methods and the other, flow rates of fluids based on fluid mechanics technology, respectively. A multi-parameter inverse acoustic scattering problem to recover airflow resistivity (AR) and mechanical properties of an air-saturated foam cylinder is solved. A wave-fluid saturated poroelastic structure interaction model based on the modified Biot theory and plane-wave decomposition using orthogonal cylindrical functions is employed to solve the inverse problem. The solutions to the inverse problem are obtained by constructing the objective functional given by the total square of the difference between predictions from the model and scattered acoustic field data acquired in an anechoic chamber. The value of the recovered AR is in good agreement with that of a slab sample cut from the cylinder and characterized using a method employing low frequency transmitted and reflected acoustic waves in a long waveguide developed by Fellah et al. [Rev. Sci. Instrum. 78(11), 114902 (2007)].
Comment on “On Dowell's simplification for acoustic cavity-structure interaction and consistent alternatives [J. Acoust. Soc. Am. 127, 22–32 (2010)]”
Authors: Nefske Donald J. , Sung Shung H. , Dowell Earl H.
Published: March 2013

This Letter describes a correction to the equations used in Ginsberg [J. Acoust. Soc. Am. 127, 22–32 (2010)] to include the rigid-body (Helmholtz) cavity mode in the modal series solution when using Dowell's method. While the correction is easy to implement, it significantly affects the results and the conclusions when using the modal series solution. Specifically, the correct formulation of Dowell's method now predicts results that agree very well with the exact solution even to the lowest frequencies.
Particle velocity estimation based on a two-microphone array and Kalman filter
Authors: Bai Mingsian R. , Juan Shen-Wei , Chen Ching-Cheng
Published: March 2013

A traditional method to measure particle velocity is based on the finite difference (FD) approximation of pressure gradient by using a pair of well matched pressure microphones. This approach is known to be sensitive to sensor noise and mismatch. Recently, a double hot-wire sensor termed Microflown became available in light of micro-electro-mechanical system technology. This sensor eliminates the robustness issue of the conventional FD-based methods. In this paper, an alternative two-microphone approach termed the u-sensor is developed from the perspective of robust adaptive filtering. With two ordinary microphones, the proposed u-sensor does not require novel fabrication technology. In the method, plane wave and spherical wave models are employed in the formulation of a Kalman filter with process and measurement noise taken into account. Both numerical and experimental investigations were undertaken to validate the proposed u-sensor technique. The results have shown that the proposed approach attained better performance than the FD method, and comparable performance to a Microflown sensor.
Model-based discrete relaxation process representation of band-limited power-law attenuation
Authors: Näsholm Sven Peter
Published: March 2013

Frequency-dependent acoustical loss due to a multitude of physical mechanisms is commonly modeled by multiple relaxations. For discrete relaxation distributions, such models correspond with causal wave equations of integer-order temporal derivatives. It has also been shown that certain continuous distributions may give causal wave equations with fractional-order temporal derivatives. This paper demonstrates analytically that if the wave-frequency ω satisfies ΩL≪ω  ≪ΩH, a continuous relaxation distribution populating only Ω∈[ΩL,ΩH] gives the same effective wave equation as for a fully populated distribution. This insight sparks the main contribution: the elaboration of a method to determine discrete relaxation parameters intended for mimicking a desired attenuation behavior for band-limited waves. In particular, power-law attenuation is discussed as motivated by its prevalence in complex media, e.g., biological tissue. A Mittag–Leffler function related distribution of relaxation mechanisms has previously been shown to be related to the fractional Zener wave equation of three power-law attenuation regimes. Because these regimes correspond to power-law regimes in the relaxation distribution, the idea is to sample the distribution's compressibility contributions evenly in logarithmic frequency while appropriately taking the stepsize into account. This work thence claims to provide a model-based approach to determination of discrete relaxation parameters intended to adequately model attenuation power-laws.
Deriving content-specific measures of room acoustic perception using a binaural, nonlinear auditory model
Authors: van Dorp Schuitman Jasper , de Vries Diemer , Lindau Alexander
Published: March 2013

Acousticians generally assess the acoustic qualities of a concert hall or any other room using impulse response-based measures such as the reverberation time, clarity index, and others. These parameters are used to predict perceptual attributes related to the acoustic qualities of the room. Various studies show that these physical measures are not able to predict the related perceptual attributes sufficiently well under all circumstances. In particular, it has been shown that physical measures are dependent on the state of occupation, are prone to exaggerated spatial fluctuation, and suffer from lacking discrimination regarding the kind of acoustic stimulus being presented. Accordingly, this paper proposes a method for the derivation of signal-based measures aiming at predicting aspects of room acoustic perception from content specific signal representations produced by a binaural, nonlinear model of the human auditory system. Listening tests were performed to test the proposed auditory parameters for both speech and music. The results look promising; the parameters correlate with their corresponding perceptual attributes in most cases.
Multichannel compression hearing aids: Effect of channel bandwidth on consonant and vowel identification by hearing-impaired listeners
Authors: Strelcyk Olaf , Li Ning , Rodriguez Joyce , Kalluri Sridhar , Edwards Brent
Published: March 2013

Aided consonant and vowel identification was measured in 13 listeners with high-frequency sloping hearing losses. To investigate the influence of compression-channel analysis bandwidth on identification performance independent of the number of channels, performance was compared for three 17-channel compression systems that differed only in terms of their channel bandwidths. One compressor had narrow channels, one had widely overlapping channels, and the third had level-dependent channels. Measurements were done in quiet, in speech-shaped noise, and in a three-talker background. The results showed no effect of channel bandwidth, neither on consonant nor on vowel identification scores. This suggests that channel bandwidth per se has little influence on speech intelligibility when individually prescribed, frequency-varying compressive gain is provided.
Speech intelligibility in reverberation with ideal binary masking: Effects of early reflections and signal-to-noise ratio threshold
Authors: Roman Nicoleta , Woodruff John
Published: March 2013

Ideal binary masking is a signal processing technique that separates a desired signal from a mixture by retaining only the time-frequency units where the signal-to-noise ratio (SNR) exceeds a predetermined threshold. In reverberant conditions there are multiple possible definitions of the ideal binary mask in that one may choose to treat the target early reflections as either desired signal or noise. The ideal binary mask may therefore be parameterized by the reflection boundary, a predetermined division point between early and late reflections. Another important parameter is the local SNR threshold used in labeling the time-frequency units as either target or background. Two experiments were designed to assess the impact of these two parameters on speech intelligibility with ideal binary masking for normal-hearing listeners in reverberant conditions. Experiment 1 shows that in order to achieve intelligibility improvements only the early reflections should be preserved by the binary mask. Moreover, it shows that the effective SNR should be accounted for when deciding the local threshold optimal range. Experiment 2 shows that with long reverberation times, intelligibility improvements are only obtained when the reflection boundary is 100 ms or less. Also, the experiment suggests that binary masking can be used for dereverberation.
Perceptual learning for speech in noise after application of binary time-frequency masks
Authors: Ahmadi Mahnaz , Gross Vauna L. , Sinex Donal G.
Published: March 2013

Ideal time-frequency (TF) masks can reject noise and improve the recognition of speech-noise mixtures. An ideal TF mask is constructed with prior knowledge of the target speech signal. The intelligibility of a processed speech-noise mixture depends upon the threshold criterion used to define the TF mask. The study reported here assessed the effect of training on the recognition of speech in noise after processing by ideal TF masks that did not restore perfect speech intelligibility. Two groups of listeners with normal hearing listened to speech-noise mixtures processed by TF masks calculated with different threshold criteria. For each group, a threshold criterion that initially produced word recognition scores between 0.56–0.69 was chosen for training. Listeners practiced with one set of TF-masked sentences until their word recognition performance approached asymptote. Perceptual learning was quantified by comparing word-recognition scores in the first and last training sessions. Word recognition scores improved with practice for all listeners with the greatest improvement observed for the same materials used in training.
Closed-loop control of flow-induced sound in a flow duct with downstream resonant cavities
Authors: Lu Z. B. , Halim D. , Cheng L.
Published: March 2013

A closed-loop-controlled surface perturbation technique was developed for controlling the flow-induced sound in a flow duct and acoustic resonance inside downstream cavities. The surface perturbation was created by piezo-ceramic THUNDER (THin layer composite UNimorph Driver and sEnsoR) actuators embedded underneath the surface of a test model with a semi-circular leading edge. A modified closed-loop control scheme based on the down-sampling theory was proposed and implemented due to the practical vibration characteristic limitation of THUNDER actuators. The optimally tuned control achieved a sound pressure reduction of 17.5 dB in the duct and 22.6 dB inside the cavity at the vortex shedding frequency, respectively. Changes brought up by the control in both flow and acoustic fields were analyzed in terms of the spectrum phase shift of the flow field over the upper surface of the test model, and a shift in the vortex shedding frequency. The physical mechanism behind the control was investigated in the view of developing an optimal control strategy.
Trans-dimensional joint inversion of seabed scattering and reflection data
Authors: Steininger Gavin , Dettmer Jan , Dosso Stan E. , Holland Charles W.
Published: March 2013

This paper examines joint inversion of acoustic scattering and reflection data to resolve seabed interface roughness parameters (spectral strength, exponent, and cutoff) and geoacoustic profiles. Trans-dimensional (trans-D) Bayesian sampling is applied with both the number of sediment layers and the order (zeroth or first) of auto-regressive parameters in the error model treated as unknowns. A prior distribution that allows fluid sediment layers over an elastic basement in a trans-D inversion is derived and implemented. Three cases are considered: Scattering-only inversion, joint scattering and reflection inversion, and joint inversion with the trans-D auto-regressive error model. Including reflection data improves the resolution of scattering and geoacoustic parameters. The trans-D auto-regressive model further improves scattering resolution and correctly differentiates between strongly and weakly correlated residual errors.
The digits-in-noise test: Assessing auditory speech recognition abilities in noise
Authors: Smits Cas , Theo Goverts S. , Festen Joost M.
Published: March 2013

A speech-in-noise test which uses digit triplets in steady-state speech noise was developed. The test measures primarily the auditory, or bottom-up, speech recognition abilities in noise. Digit triplets were formed by concatenating single digits spoken by a male speaker. Level corrections were made to individual digits to create a set of homogeneous digit triplets with steep speech recognition functions. The test measures the speech reception threshold (SRT) in long-term average speech-spectrum noise via a 1-up, 1-down adaptive procedure with a measurement error of 0.7 dB. One training list is needed for naive listeners. No further learning effects were observed in 24 subsequent SRT measurements. The test was validated by comparing results on the test with results on the standard sentences-in-noise test. To avoid the confounding of hearing loss, age, and linguistic skills, these measurements were performed in normal-hearing subjects with simulated hearing loss. The signals were spectrally smeared and/or low-pass filtered at varying cutoff frequencies. After correction for measurement error the correlation coefficient between SRTs measured with both tests equaled 0.96. Finally, the feasibility of the test was approved in a study where reference SRT values were gathered in a representative set of 1386 listeners over 60 years of age.
The investigation of guided wave propagation around a pipe bend using an analytical modeling approach
Authors: Sanderson R. M. , Hutchins D. A. , Billson D. R. , Mudge P. J.
Published: March 2013

Guided wave inspection has the advantage of providing full volumetric coverage of tens of meters of pipe from a single test location. However, guided wave behavior is complex and there are many factors to consider such as the numerous possible vibrational modes and multiple reflections. The guided wave inspection technique is potentially valuable for pipelines that cannot be inspected with internal “pigs.” However, in situations such as this, there are often bends in the pipe and the presence of the bend is known to distort the received signals. In order to address this issue, a study has been carried out that uses a combination of finite element analysis and experimentation to understand the behavior of guided waves in pipe bends. In addition to this, an analytical modeling methodology is put forward that uses basic information from finite element models of pipe bends to create a computationally fast solution to a potentially infinite number of scenarios. The analytical model can be used to both predict the effects of pipe bends on a range of signals and undo the distortion caused by pipe bends. Examples of this are given and compared to finite element results for flaws beyond pipe bends.
Multiple-instrument polyphonic music transcription using a temporally constrained shift-invariant model
Authors: Benetos Emmanouil , Dixon Simon
Published: March 2013

A method for automatic transcription of polyphonic music is proposed in this work that models the temporal evolution of musical tones. The model extends the shift-invariant probabilistic latent component analysis method by supporting the use of spectral templates that correspond to sound states such as attack, sustain, and decay. The order of these templates is controlled using hidden Markov model-based temporal constraints. In addition, the model can exploit multiple templates per pitch and instrument source. The shift-invariant aspect of the model makes it suitable for music signals that exhibit frequency modulations or tuning changes. Pitch-wise hidden Markov models are also utilized in a postprocessing step for note tracking. For training, sound state templates were extracted for various orchestral instruments using isolated note samples. The proposed transcription system was tested on multiple-instrument recordings from various datasets. Experimental results show that the proposed model is superior to a non-temporally constrained model and also outperforms various state-of-the-art transcription systems for the same experiment.
Avoiding a Spanning Cluster in Percolation Models
Authors: Cho Y. S. , Hwang S. , Herrmann H. J. , Kahng B.
Published: March 2013

Limits in Percolation Models

Slight changes in the number of connections within a network that form at random (for example, connections in social networks) can lead to a huge increase in connectivity, a phenomenon termed "explosive percolation." These percolation transitions are often studied with Erdös and Rényi models, in which edges connecting pairs of vertices in a network are added randomly or according to a rule. Whether these transitions are continuous in nature has been the subject of several recent studies.

Cho
et al.

(p.
1185
; see the Perspective by
Ziff
) examined the effect of avoiding bridge bonds that create a spanning cluster (one that completes the percolation path) on the continuity of transitions for a
d
-dimensional lattice (up to six dimensions). Analytical arguments and numerical studies reveal a critical value for the number of bonds
m
below which the percolation transition is continuous and above which it is discontinuous. The critical value depends on
d
and on the fractal dimension of the bridge bonds of the clusters.
Behavioral Economics and the Retirement Savings Crisis
Authors: Benartzi Shlomo , Thaler Richard H.
Published: March 2013

Behavioral economics can be scaled up to have a major, positive impact on certain behaviors, such as retirement savings.
Quantum Spintronics: Engineering and Manipulating Atom-Like Spins in Semiconductors
Authors: Awschalom David D. , Bassett Lee C. , Dzurak Andrew S. , Hu Evelyn L. , Petta Jason R.
Published: March 2013

The past decade has seen remarkable progress in isolating and controlling quantum coherence using charges and spins in semiconductors. Quantum control has been established at room temperature, and electron spin coherence times now exceed several seconds, a nine–order-of-magnitude increase in coherence compared with the first semiconductor qubits. These coherence times rival those traditionally found only in atomic systems, ushering in a new era of ultracoherent spintronics. We review recent advances in quantum measurements, coherent control, and the generation of entangled states and describe some of the challenges that remain for processing quantum information with spins in semiconductors.
The Chemistry of Social Life

The Emergence of Organizations and Markets
John F. Padgett and Walter W. Powell, Eds.

Princeton University Press, Princeton, NJ, 2012. 607 pp. $120. ISBN 9780691148670. Paper, $45. ISBN 9780691148878.
Authors: Macy Michael
Published: March 2013

Drawing on complexity theory, network autocatalytic mechanisms, and original historical case studies, the authors argue for the importance of intertwined networks in social and organizational transformations.
Killing by Bactericidal Antibiotics Does Not Depend on Reactive Oxygen Species
Authors: Keren Iris , Wu Yanxia , Inocencio Julio , Mulcahy Lawrence R. , Lewis Kim
Published: March 2013

Antibiotic Mechanisms Revisited

Several recent studies have suggested that bactericidal antibiotics kill cells by a common mechanism involving reactive oxygen species (ROS). Two groups tested this hypothesis using diverse experiments, with both finding that quinolone, lactam, and aminoglycoside antibiotics had similar efficacy for killing in the presence or absence of oxygen (or nitrate).

Liu
et al.

(p.
1210
) saw no increase in hydrogen peroxide production in antibiotic-exposed cells and found no association between antibiotic exposure and the expected symptoms of oxidative damage, such as the breakdown of iron-sulfur clusters in enzymes or of hydroxyl radical injuries to DNA. Similarly,

Keren
et al.

(p.
1213
) found no correlation between the production of ROS, inferred from hydroxyphenyl fluorescein dye measurements, and bacterial survival, nor was there any significant protective effect engendered by thiourea. The results do not support a common mode of action for bactericidal antibiotics mediated by ROS.
Cell Death from Antibiotics Without the Involvement of Reactive Oxygen Species
Authors: Liu Yuanyuan , Imlay James A.
Published: March 2013

Antibiotic Mechanisms Revisited

Several recent studies have suggested that bactericidal antibiotics kill cells by a common mechanism involving reactive oxygen species (ROS). Two groups tested this hypothesis using diverse experiments, with both finding that quinolone, lactam, and aminoglycoside antibiotics had similar efficacy for killing in the presence or absence of oxygen (or nitrate).

Liu
et al.

(p.
1210
) saw no increase in hydrogen peroxide production in antibiotic-exposed cells and found no association between antibiotic exposure and the expected symptoms of oxidative damage, such as the breakdown of iron-sulfur clusters in enzymes or of hydroxyl radical injuries to DNA. Similarly,

Keren
et al.

(p.
1213
) found no correlation between the production of ROS, inferred from hydroxyphenyl fluorescein dye measurements, and bacterial survival, nor was there any significant protective effect engendered by thiourea. The results do not support a common mode of action for bactericidal antibiotics mediated by ROS.
Aire-Dependent Thymic Development of Tumor-Associated Regulatory T Cells
Authors: Malchow Sven , Leventhal Daniel S. , Nishi Saki , Fischer Benjamin I. , Shen Lynn , Paner Gladell P. , Amit Ayelet S. , Kang Chulho , Geddes Jenna E. , Allison James P. , Socci Nicholas D. , Savage Peter A.
Published: March 2013

On the Origin of Tumor T
regs

The tumor microenvironment is often seeded with regulatory T cells (T
regs
), which inhibit antitumor immunity. Using mice with genetically driven prostate cancer,

Malchow
et al.

(p.
1219
; see the Perspective by
Joshi and Jacks
) found a population of T
regs
that were enriched in the prostate of tumor-bearing mice. Surprisingly, these cells were also present in female mice and were found to be specific, not for a tumor-specific antigen, but rather for an antigen normally expressed in the prostate. Prostate antigen–specific T
regs
arose in the thymus and their selection was dependent on Aire, a protein that drives the expression of tissue-specific antigens in the thymus. Thus, T
regs
that seed tumors likely arise in the thymus, are not necessarily tumor-specific, and are recruited and/or expand in an organ when a tumor arises.
(De)Personalized Medicine
Authors: Horwitz Ralph I. , Cullen Mark R. , Abell Jill , Christian Jennifer B.
Published: March 2013

Integration of clinical, social, and environmental data with genomic and molecular information is needed to develop a personalized approach to medicine.
Red Wine, Toast of the Town (Again)
Authors: Yuan Hua , Marmorstein Ronen
Published: March 2013

The debate may be over on whether resveratrol and other small molecules directly activate an enzyme implicated in longevity.

[Also see Report by

Hubbard
et al.

]
Denial of Catastrophic Risks
Authors: Rees Martin
Published: March 2013

In a media landscape saturated with sensational science stories and "end of the world" Hollywood productions, it may be hard to persuade the wide public that real catastrophes could arise as unexpectedly as the 2008 financial crisis, and have a far greater impact. Society could be dealt shattering blows by the misapplication of technologies that exist already or could emerge within the coming decades. Some of the scenarios that have been envisaged may indeed be science fiction, but others may be disquietingly real. I believe these "existential risks" deserve more serious study. Those fortunate enough to live in the developed world fret too much about minor hazards of everyday life: improbable air crashes, possible carcinogens in food, low radiation doses, and so forth. But we should be more concerned about events that have not yet happened but which, if they occurred even once, could cause worldwide devastation.
Erratum: Sarcolemma: Tension Transmission
Authors: Lamport Harold
Published: March 2013

In the technical comment "Sarcolemma: tension transmission" by H. Lamport [150, 1846 (31 Dec. 1965)] the reference given in the last sentence should have read, "
Proc. Intern. Physiol. Cong. 20th
(1956).
Early Treatment May Have Cured Infant of HIV Infection
Authors: Cohen Jon
Published: March 2013

Anti-HIV drugs started within 2 days of birth clear signs of infection in a baby.
Septic Shock after Seasonal Influenza Vaccination in an HIV-Infected Patient during Treatment with Etanercept for Rheumatoid Arthritis: a Case Report
Authors: De Nardo Pasquale , Bellagamba Rita , Corpolongo Angela , Gentilotti Elisa , Taglietti Fabrizio , Rosati Silvia , Galeazzi Mauro , Sebastiani Gian Domenico , Quinti Isabella , Nicastri Emanuele
Published: March 2013

Anti-tumor necrosis factor alpha (anti-TNF-α) is used in the treatment of rheumatic diseases not responsive to first-line regimens. Data on the safety of anti-TNF-α in HIV-infected patients are scarce and conflicting. We describe a case of septic shock and multiorgan failure that occurred after etanercept initiation and influenza vaccination in an HIV-infected woman with rheumatoid arthritis.
OXA-258 from Achromobacter ruhlandii: a Species-Specific Marker
Authors: Papalia Mariana , Almuzara Marisa , Cejas Daniela , Traglia German , Ramírez Maria Soledad , Galanternik Laura , Vay Carlos , Gutkind Gabriel , Radice Marcela
Published: March 2013

A new
bla
OXA-258
gene is described as a species-specific taxonomic marker for
Achromobacter ruhlandii
isolates (all recovered from cystic fibrosis patients). Even though OXA-258 differs from OXA-114 variants, isolates could be misidentified as
A. xiloxosidans
by the amplification of an inner fragment from the OXA-coding gene. A robust identification of
A. ruhlandii
can be achieved by sequencing this single OXA gene, as well as by a more laborious recently proposed multilocus sequence-typing (MLST) scheme.
Comparison of the cobas 4800 CT/NG Test with Culture for Detecting Neisseria gonorrhoeae in Genital and Nongenital Specimens in a Low-Prevalence Population in New Zealand
Authors: Bromhead Collette , Miller Amanda , Jones Mark , Whiley David
Published: March 2013

To assess the clinical utility of replacing microbial culture for
Neisseria gonorrhoeae
with a nucleic acid amplification test (NAAT), we compared
N. gonorrhoeae
culture with the cobas 4800 CT/NG test for 18,247 urogenital and 666 nongenital samples. For urogenital specimens, the sensitivity, specificity, and positive and negative predictive values of the cobas
N. gonorrhoeae
PCR were 98.7%, 100%, 95.6%, and 100%, respectively, and for nongenital specimens, the values were 100%, 99.8%, 92.9%, and 100%, respectively. In our test population, 37% (10,185) of patients tested over the study period were screened for
C. trachomatis
by PCR but were not screened for gonorrhea by culture. Of these, 43 were
N. gonorrhoeae
positive by PCR and therefore went undiagnosed. The cobas 4800 CT/NG test diagnosed 33% (
n
= 30) more urogenital and 25% (
n
= 3) more rectal gonorrhea infections than culture and, based on the above performance indicators, does not require supplementary testing for urogenital or rectal specimens. The ability to test noninvasive specimens (such as urine and self-taken vulvovaginal swabs) for
N. gonorrhoeae
will enable more patients to be screened for infection, thus offering significant positive public health benefits.
Performance of the MagNA Pure 96 System for Cytomegalovirus Nucleic Acid Amplification Testing in Clinical Samples
Authors: Edelmann A. , Eichenlaub U. , Lepek S. , Krüger D. H. , Hofmann J.
Published: March 2013

This report shows the performance of MagNA Pure 96 automated nucleic acid extraction for the quantitative detection of cytomegalovirus DNA in clinical samples by real-time PCR. The obtained results demonstrate that this workflow is characterized by high sensitivity and linearity and ensures reliable, reproducible clinical diagnostics.