bluuebunny/crossref_metadata_2025 huggingface dataset:
Avian influenza in shorebirds: experimental infection of ruddy turnstones (Arenaria interpres) with avian influenza virus
Authors: Hall Jeffrey S. , Krauss Scott , Franson J. Christian , TeSlaa Joshua L. , Nashold Sean W. , Stallknecht David E. , Webby Richard J. , Webster Robert G.
Published: April 2012

Please cite this paper as: Hall et al. (2012) Avian influenza in shorebirds: experimental infection of ruddy turnstones (Arenaria interpres) with avian influenza virus. Influenza and Other Respiratory Viruses DOI: 10.1111/j.1750‐2659.2012.00358.x.

Background  Low pathogenic avian influenza viruses (LPAIV) have been reported in shorebirds, especially at Delaware Bay, USA, during spring migration. However, data on patterns of virus excretion, minimal infectious doses, and clinical outcome are lacking. The ruddy turnstone (Arenaria interpres) is the shorebird species with the highest prevalence of influenza virus at Delaware Bay.

Objectives  The primary objective of this study was to experimentally assess the patterns of influenza virus excretion, minimal infectious doses, and clinical outcome in ruddy turnstones.

Methods  We experimentally challenged ruddy turnstones using a common LPAIV shorebird isolate, an LPAIV waterfowl isolate, or a highly pathogenic H5N1 avian influenza virus. Cloacal and oral swabs and sera were analyzed from each bird.

Results  Most ruddy turnstones had pre‐existing antibodies to avian influenza virus, and many were infected at the time of capture. The infectious doses for each challenge virus were similar (103·6–104·16 EID50), regardless of exposure history. All infected birds excreted similar amounts of virus and showed no clinical signs of disease or mortality. Influenza A‐specific antibodies remained detectable for at least 2 months after inoculation.

Conclusions  These results provide a reference for interpretation of surveillance data, modeling, and predicting the risks of avian influenza transmission and movement in these important hosts.
Increased reactions to pediatric influenza vaccination following concomitant pneumococcal vaccination
Authors: Van Buynder Paul G. , Frosst Gillian , Van Buynder Jan L. , Tremblay Francios‐William , Ross Alie , Jardine Claire , Fei Bao Gang
Published: April 2012

Please cite this paper as: Van Buynder et al. (2013). Increased reactions to pediatric influenza vaccination following concomitant pneumococcal vaccination Influenza and Other Respiratory Viruses 7(2) 184–190.

Background  Influenza in children causes significant morbidity and hospitalizations and also some mortality particularly in children <5 years of age. Influenza vaccination in children has been shown to be safe and effective, but in 2010 the pediatric influenza vaccination program was suspended in Western Australia after the rate of febrile convulsions observed (9/1000 doses) was 55 times the previously reported rate.

In 2009, over 80% of all children in New Brunswick were vaccinated with an adjuvanted monovalent H1N1 vaccine shown to have very high effectiveness, raising the prospect of potential hyper‐responsiveness because of residual protection. We conducted enhanced post‐marketing surveillance to monitor local and general reactions.

Methods  Parents of participating children seen at dedicated vaccination clinics were given influenza vaccine survey kits to record local and general symptoms up to 3 days following receipt of season influenza vaccine.

Results  Febrile reactions of ≥38° occurred in <10% of children who received a first dose of seasonal influenza vaccine (n = 660) and severe febrile incidents with fever ≥39° were uncommon. Concurrent administration of other vaccine(s) including conjugated pneumococcal vaccine appeared to increase reactogenicity. No child in the study had a febrile convulsion.

Conclusion  Influenza vaccines in children are safe, and this study provides a baseline for rapid assessment studies at the start of a vaccine season. Parents should be aware of increased fevers with concurrent vaccine administration, and antipyretics should be considered.
Malformations of Cortical Development
Authors: Aronica Eleonora , Becker Albert J. , Spreafico Roberto
Published: April 2012

Structural abnormalities of the brain are increasingly recognized in patients that suffer from pharmacoresistant focal epilepsies by applying high‐resolution imaging techniques. In many of these patients, epilepsy surgery results in control of seizures. Neuropathologically, a broad spectrum of malformations of cortical development (MCD) is observed in respective surgical brain samples. These samples provide a unique basis to further understand underlying pathomechanisms by molecular approaches and develop improved diagnostics and entirely new therapeutic perspectives. Here we provide a comprehensive description of neuropathological findings, available classification systems as well as molecular mechanisms of MCDs. We emphasize the recently published ILEA classification system for focal cortical dysplasias (FCDs), which are now histopathologically distinguished as types I to III. However, this revised classification system represents a major challenge for molecular neuropathologists, as the underlying pathomechanisms in virtually all FCD entities will need to be specified in detail. The fact that only recently, the mammalian target of rapamycin (mTOR)‐antagonist Everolimus has been introduced as a treatment of epilepsies in the context of tuberous sclerosis‐associated brain lesions is a striking example of a successful translational “bedside to bench and back” approach. Hopefully, the exciting clinico‐pathological developments in the field of MCDs will in short term foster further therapeutic breakthroughs for the frequently associated medically refractory epilepsies.
Fatty Acid Composition of 12 Fish Species  from the Black Sea
Authors: C huang L.‐T. , Bülbül U. , Wen P.‐C. , Glew R.H. , Ayaz F.A.
Published: April 2012

Abstract:  The long‐chain polyunsaturated fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are healthful to humans, particularly in promoting growth and cognitive development in infants and young children, and in reducing the risk of cardiovascular disease. Though the populations who inhabit the Trabzon province of Turkey include seafood from the Black Sea in their diet, knowledge of the fatty acid composition and content of these fish is scant. Fatty acid analysis was performed on freeze‐dried muscle tissue of 12 species of fish purchased in markets in Trabzon. The fat content varied from 0.2% (garfish) to 12% (shad) of dry weight. The highest DHA and DHA plus EPA contents were found in horse mackerel 16.1 and 20.6 mg/g dry weight, respectively. Only in sea bass and sea bream did the essential fatty acid linoleic acid account for more than 10% of the fatty acid total. For all 12 species, arachidonic acid accounted for 0.09% to 7.64% of the fatty acid total. Oleic acid varied greatly from 0.14% (garfish) to 32.7% (shad). The omega‐3/omega‐6 fatty acid ratio ranged from 0.8 to 25. A 100 g serving of fresh horse mackerel would contribute 586 mg of DHA to the diet, which exceeds the recommended daily intake of 200 to 300 mg of DHA for pregnant and lactating women. These data indicate that some, but not all, of the 12 fish species from the Black Sea fish we studied could contribute significantly to satisfy the DHA and EPA needs of the inhabitants of the eastern Black Sea region of Turkey.

Practical Application:  The information in the present paper will be of practical value from a health perspective for populations who consume these fish and for food producers, as well as scholars interested in fishery and aquaculture and biodiversity and marine ecology when we consider an increasing pollution of our marine ecosystem in our green planet.
High cyanobacterial nifH gene diversity in Arctic seawater and sea ice brine
Authors: Díez Beatriz , Bergman Birgitta , Pedrós‐Alió Carlos , Antó Meritxell , Snoeijs Pauline
Published: April 2012

Although cyanobacterial diazotrophs are common in Arctic terrestrial and freshwater habitats, they have been assumed to be absent from Arctic marine habitats. We report here a high diversity of cyanobacterial nifH genes in Fram Strait and the Greenland Sea. The nifH gene encodes the iron protein of the nitrogenase enzyme complex, which is essential for biological N2 fixation. Using primers specific for nifH genes we uncovered communities of autotrophic and heterotrophic bacteria in sea ice brine and seawater between latitudes 65 and 81°N. Cyanobacteria (Oscillatoriales and Chroococcales) with known marine planktonic and benthic distributions were distinguished, alongside a mix of metabolically versatile eubacteria (nifH Clusters I and III). Using primers selective for cyanobacterial nifH genes we identified filamentous non‐heterocystous Trichodesmium‐like and LPP (Leptolyngbya, Phormidium and Plectonema)‐like Oscillatoriales, as well as Cyanothece‐like Chroococcales in a brine sample from 81°N. The occurrence of Trichodesmium‐like cyanobacteria was further confirmed by sequences of the hetR gene of Trichodesmium. Microscopic examinations confirmed the presence of viable filamentous and unicellular cyanobacteria. Our results reveal the potential for microbial N2 fixation in the Arctic seas. However, it is still left to determine if these genes are also metabolically active before any biogeochemical importance of diazotrophy in the polar oceans can be assessed.
A comparative analysis of the accuracy of different direct impression techniques for multiple implants
Authors: Öngül D , Gökçen‐Röhlig B , Şermet B , Keskin H
Published: April 2012

Background:  The aim of this study was to compare the accuracy of different direct implant impression techniques for edentulous arches with multiple implants.

Methods:  Five experimental groups (n = 5) were assembled. Experimental models were created by a direct splinted technique (EG2 to EG5) and a non‐splinted technique (EG1). In EG2 and EG3 synOcta impression copings were splinted with an acrylic resin bar, and in EG4 and EG5 with a light‐curing composite resin bar. In EG3 and EG5 the resin bars were sectioned, while the other experimental groups were not. Three‐dimensional discrepancies were measured by a computerized coordinate measuring machine. Distortion values among the groups were analysed using one‐way repeated measures ANOVA. The post hoc Tukey’s test was then performed for multiple comparisons.

Results:  The highest accuracy was obtained in EG2 (mean deviation: 12.70 μm). The acrylic bars demonstrated less deviation (12.70 μm and 22.71 μm) from the master model than the light‐curing composite resin groups and the non‐splinted group (41.09 μm). The post hoc Tukey’s test showed no significant difference among the groups when the effect of splint design on accuracy was investigated.

Conclusions:  For situations where impressions of multiple implants are to be made, splinting impression copings with acrylic resin demonstrate superior results than the non‐splinted technique and splinting with light‐curing composite.
Older patient, physician and pharmacist perspectives about community pharmacists' roles
Authors: Tarn Derjung M , Paterniti Debora A , Wenger Neil S , Williams Bradley R , Chewning Betty A
Published: April 2012

Objectives

To investigate older patient, physician and pharmacist perspectives about the role of pharmacists in pharmacist-patient interactions.

Methods

Eight focus-group discussions were held in senior centres, community pharmacies and primary care physician offices. Participants were 42 patients aged 63 years and older, 17 primary care physicians and 13 community pharmacists. Qualitative analysis of the focus-group discussions was performed.

Key findings

Participants in all focus groups indicated that pharmacists are a good resource for basic information about medications. Physicians appreciated pharmacists' ability to identify drug interactions, yet did not comment on other specific aspects related to patient education and care. Physicians noted that pharmacists often were hindered by time constraints that impeded patient counselling. Both patient and pharmacist participants indicated that patients often asked pharmacists to expand upon, reinforce and explain physician–patient conversations about medications, as well as to evaluate medication appropriateness and physician treatment plans. These groups also noted that patients confided in pharmacists about medication-related problems before contacting physicians. Pharmacists identified several barriers to patient counselling, including lack of knowledge about medication indications and physician treatment plans.

Conclusions

Community-based pharmacists may often be presented with opportunities to address questions that can affect patient medication use. Older patients, physicians and pharmacists all value greater pharmacist participation in patient care. Suboptimal information flow between physicians and pharmacists may hinder pharmacist interactions with patients and detract from patient medication management. Interventions to integrate pharmacists into the patient healthcare team could improve patient medication management.
Influence of neural adjustments and muscle oxygenation on task failure during sustained isometric contractions with elbow flexor muscles
Authors: Booghs Cédric , Baudry Stéphane , Enoka Roger , Duchateau Jacques
Published: April 2012

This study investigated the adjustments in muscle activation and oxygenation in biceps and triceps brachii during two tasks sustained to failure at 20 and 60% of the maximal voluntary contraction (MVC) force. The tasks required participants either to push against a rigid restraint (force task) or to support an inertial load (position task) with the elbow flexor muscles. The surface EMG was recorded for biceps brachii, brachioradialis, triceps brachii and trapezius superior muscles. Muscle oxygenation of biceps and triceps brachii was measured by near‐infrared spectroscopy. The position task was briefer (404 ± 159 s) than the force task (533 ± 194 s) when performed at 20% MVC (P= 0.011), but endurance time did not differ at 60% MVC (54 ± 19 versus 64 ± 16 s, respectively; P= 0.13). Biceps brachii oxygenation decreased slightly (by ∼7%) during tasks performed at 20% MVC, whereas it dropped (−40%) for tasks sustained at 60% MVC. However, the decrease in muscle oxygenation was not a significant predictor of time to failure at the two target forces, although its contribution to muscle fatigue cannot be completely ruled out at 60% MVC. In contrast, time to failure was predicted by the increase in EMG of biceps brachii for both tasks at 20% MVC, and EMG of brachioradialis and trapezius for both tasks at 60% MVC. These results suggest that neural adjustments rather than muscle oxygenation limited the time to failure for the force and position tasks at low and high target forces.
Analytical
Investigation of the Effects of Induction Motor Transients on Compressor Drive
Shafts
Authors: Srinivasan Anand
Published: April 2012

Centrifugal compressors driven by induction motors are most common in the turbomachinery industry. When sudden transients occur in the driver due to upsets in electrical supply to the motor, the air-gap torque generated by the motor undergoes a transient spike. This in turn gets transmitted through the coupling to the drive-shaft of the driven equipment, causing momentary high spikes in vibration that are torsional in nature, and can sometimes result in shaft torques that can create catastrophic damage to driven equipment components. In order to analytically predict these peak torques that can occur during transients, a complete drive-train torsional model needs to be created for the mechanical system, and the driving torque values need to be derived from the motor electrical system of equations. Various line faults are possible with induction motor driven equipment. A generalized analytical procedure based on motor electrical parameters to predict the peak shaft torques of compressor drive shafts is investigated in this paper. The effects of shaft transients due to 3-phase short circuits and reclosures are analyzed. The simulation has been performed for an industrial compressor train, and has been presented from a mechanical system point of view, rather than electrical. Comparisons and inferences are also made based on the simulation results.
Assessment of Low Cycle Fatigue Life of Steam Turbine Rotor Based on a Thermodynamic Approach
Authors: Sun Yong-Jian , Hu Li-Sheng
Published: April 2012

A new nonlinear model is proposed to assess the low cycle fatigue life of a 300 MW steam turbine rotor. Manson-Coffin equation and cyclic stress-strain relationship are employed to eliminate the unmeasured parameters, so all the parameters in model are measurable. Through comparison with that from the linear accumulation theory and continuum damage mechanics theory the results show this new nonlinear model describes the damage accumulation well and precisely in accordance with the practical test data. This approach supplies a new way to assess the damage of steam turbine rotor with satisfactory precision in engineering.
Gas Turbine Emission Characteristics in Perfectly Premixed Combustion
Authors: Elkady A. M. , Herbon J. , Kalitan D. M. , Leonard G. , Akula R. , Karim H. , Hadley M.
Published: April 2012

In the present study, a simple perfectly premixed research burner was utilized at temperatures, pressures and residence times representative of an industrial gas turbine cycle to identify the lower limit of NOx and CO emissions, and to establish an emissions benchmark for practical gas turbine combustors. In addition to experimental data, a chemical reactor model has been utilized for the prediction of the NOx and CO, based on detailed chemical reaction mechanisms. Several current kinetics mechanisms were evaluated and subsequently compared to the experimental data. In addition, sensitivity analysis was performed to identify important reactions at the conditions tested, and will be discussed.
A High Temperature High Bandwidth Fast Response Total Pressure Probe for Measurements in a Multistage Axial Compressor
Authors: Mersinligil Mehmet , Brouckaert Jean-François , Courtiade Nicolas , Ottavy Xavier
Published: April 2012

Over the last decades, fast response aerodynamic probes have been recognized as a robust measurement technique to provide time-resolved flow field data in turbomachinery environments. Still, most of the existing probe designs are restricted to low temperature applications (<120 °C) either because of sensor temperature range limitations or packaging issues. Measurements in turbomachines also require a small probe size often with a very high bandwidth which are conflicting constraints difficult to satisfy simultaneously. This contribution therefore presents the development of a novel miniature (∅ 2.5 mm ) high temperature single sensor total pressure probe, designed for operation up to 250 °C with a very high bandwidth of 250 kHz. The probe main element is a 1.7 mm diameter commercial piezoresistive transducer placed in a Pitot type arrangement with a flush mounted sensor to provide the highest bandwidth. The details of the probe design are presented as well as the probe calibrations in pressure and in temperature. The effects of using a thermal compensation module or a sense resistor to monitor the temperature drift are described in the context of measurement uncertainty. The probes were characterized in terms of aerodynamic characteristics versus flow angle and Mach number. Shock tube tests have shown a dynamic response of the probe with sensor resonance frequencies well over 300 kHz, with a flat frequency range up to 250 kHz. Two probe prototypes were manufactured and first used in the 3½-stage high speed axial compressor CREATE of the LMFA at École Centrale de Lyon in France. The probes were traversed at each interblade row plane up to temperatures of 180 °C and absolute pressure of 3 bars. The probe was able to resolve the high blade passing frequencies (∼16 kHz) and several harmonics including rotor-stator interaction frequencies up to 200 kHz. Besides the average total pressure distributions from the radial traverses, phase-locked averages and random unsteadiness are presented. The probe spatial and temporal resolutions are discussed in the context of those results.
Coupled Nonlinear Effects of Random Surface Roughness and Rarefaction on Slip Flow in Ultra-Thin Film Gas Bearing Lubrication
Authors: Zhang Wen-Ming , Meng Guang , Peng Zhi-Ke , Chen Di
Published: April 2012

A mathematical model of gaseous slip flow in ultra-thin film gas bearings is numerically analyzed incorporating effects of surface roughness, which is characterized by fractal geometry. The Weierstrass-Mandelbrot (W-M) function is presented to represent the multiscale self-affine roughness of the surface. A modified Reynolds equation incorporating velocity slip boundary condition is applied for the arbitrary range of Knudsen numbers in the slip and transition regimes. The effects of bearing number, Knudsen number, geometry parameters of the bearing and roughness parameters on the complex flow behaviors of the gas bearing are investigated and discussed. Numerical solutions are obtained for various bearing configurations under the coupled effects of rarefaction and roughness. The results indicate that roughness has a more significant effect on higher Knudsen number (rarefaction effect) flows with higher relative roughness. Surface with larger fractal dimensions yield more frequency variations in the surface profile, which result in an obviously larger incremental pressure loss. The Poiseuille number increases not only with increasing of rarefaction effect but also with increasing the surface roughness. It can also be observed that the current study is in good agreement with solutions obtained from the linearized Boltzmann equation.
Knowledge-Based System for Supporting the Design of a Plate-Press
Authors: Potočnik David , Ulbin Miran , Dolšak Bojan
Published: April 2012

This paper presents a knowledge-based system capable of giving the designer quality support when making decisions from the aspect of modeling the reinforcement of a plate-press within a position of maximum compressive load, and by choosing suitable material for the plate. Based on the selected combination of reinforcement and material, this system acquaints the user with the size and position of the largest comparative stress, and the greatest nodal displacement in the load-direction. This system operates based on the implemented knowledge of experts in the execution of design, material selection, and numerical analysis based on the finite-element method (FEM), which was written with the help of parameters within the knowledge-base of the CATIA V5 CAD-system. Using this system gives the user an opportunity to reach conclusions that are crucial for designing a plate-press or pressure-loaded die-elements, in general. The results reveal that the system can dramatically shorten design time and improve design quality in comparison to manual design process.
Pilot program on patient dosimetry in pediatric interventional cardiology in Chile
Authors: Ubeda Carlos , Vano Eliseo , Miranda Patricia , Leyton Fernando
Published: April 2012

Purpose:

The aim of this study was to present the results of a pilot program on patient dosimetry carried out in Chile during the last 5 yr, using a biplane x‐ray angiography system settled for pediatrics. This research was conducted in Latin America under the auspices of the International Atomic Energy Agency (IAEA) supporting programs on radiological protection (RP) of patients.

Methods:

Patient age, gender, weight, height, number of cine series, total number of cine frames, fluoroscopy time, and two dosimetric quantities [air kerma‐area product (Pka) and cumulative dose (CD) at the patient entrance reference point] were recorded for each procedure.

Results:

The study includes 544 patients grouped into four age groups. The distributions by age group were 150 for <1 yr; 203 for 1 to <5 yr; 97 for 5 to <10 yr; and 94 for 10 to <16 yr. Median values of Pka and CD for the four age groups were 0.94, 1.46, 2.13, and 5.03 Gy cm2 and 23.9, 26.8, 33.5, and 51.6 mGy, respectively. No significant statistical differences were found between diagnostic and therapeutic procedures. A moderate correlation (r = 0.64) was seen between Pka and patient weight.

Conclusions:

The dose values reported in this paper were lower than those published in the previous work for the same age groups as a result of the optimization actions carried out by cardiologists and medical physicists with the support of the IAEA. Methodology and results will be used as a starting point for a wider survey in Chile and Latin America with the goal to obtain regional diagnostic reference levels as recently recommended by the International Commission on Radiological Protection for interventional procedures.
The Physics of a Simple Camera Stabilizer
Authors: Bartlett Albert A.
Published: April 2012

Approximately 50,000 people ran and walked down the street past my home in the 33rd annual running of the 10-km Bolder Boulder footrace on the morning of Memorial Day, May 30, 2011.1,2 In addition to the serious runners, there were many individuals dressed in all manner of amusing festival costumes; some were jogging and some were walking. Early in the race I noticed a man who was jogging while using his right hand to hold a vertical wooden pole that was about three meters long and perhaps three centimeters in diameter. On the upper end of the pole, above the heads of the other runners, was a small video camera that was pointed forward to photograph the runners who were ahead of the jogger. At the lower end of the vertical pole were fastened several blocks of wood.
Online Prelectures: An Alternative to Textbook Reading Assignments
Authors: Sadaghiani Homeyra R.
Published: April 2012

To engage students in a more meaningful discussion of course material and prompt their higher thinking skills, most instructors expect students to read the course textbook for initial exposure to the course content before class. However, as many instructors are aware, most students do not read their textbook throughout the quarter.1,2 At California State Polytechnic University, Pomona (Cal Poly Pomona) we have adopted web-based multimedia learning modules (MLMs) as prelecture assignments to help students to prepare for the class activities. The MLMs place lecture contents into the hands and control of the learners; similar to “flipped”3 or “inverted”4 classroom approaches, this method allows students to receive key course content outside of class and apply and analyze the content actively during class. In addition to initial exposure to basic principle, the MLMs provide additional worked examples that cannot be thoroughly covered in class.
Determining the speed of sound with stereo headphones
Authors: Vogt Patrik , Kuhn Jochen
Published: April 2012

In this example we describe how the speed of sound can be determined using simple stereo headphones (ear buds) and sound analysis freeware.
The influence of stop consonants’ perceptual features on the Articulation Index model
Authors: Singh Riya , Allen Jont B.
Published: April 2012

Studies on consonant perception under noise conditions typically describe the average consonant error as exponential in the Articulation Index (AI). While this AI formula nicely fits the average error over all consonants, it does not fit the error for any consonant at the utterance level. This study analyzes the error patterns of six stop consonants /p, t, k, b, d, g/ with four vowels (/ɑ/, /ɛ/, /I/, /ae/), at the individual consonant (i.e., utterance) level. The findings include that the utterance error is essentially zero for signal to noise ratios (SNRs) at least −2 dB, for >78% of the stop consonant utterances. For these utterances, the error is essentially a step function in the SNR at the utterance’s detection threshold. This binary error dependence is consistent with the audibility of a single binary defining acoustic feature, having zero error above the feature’s detection threshold. Also 11% of the sounds have high error, defined as ≥20% for SNRs greater than or equal to −2 dB. A grand average across many such sounds, having a natural distribution in thresholds, results in the error being exponential in the AI measure, as observed. A detailed analysis of the variance from the AI error is provided along with a Bernoulli-trials analysis of the statistical significance.
A generalized power-law detection algorithm for humpback whale vocalizations
Authors: Helble Tyler A. , Ierley Glenn R. , D’Spain Gerald L. , Roch Marie A. , Hildebrand John A.
Published: April 2012

Conventional detection of humpback vocalizations is often based on frequency summation of band-limited spectrograms under the assumption that energy (square of the Fourier amplitude) is the appropriate metric. Power-law detectors allow for a higher power of the Fourier amplitude, appropriate when the signal occupies a limited but unknown subset of these frequencies. Shipping noise is non-stationary and colored and problematic for many marine mammal detection algorithms. Modifications to the standard power-law form are introduced to minimize the effects of this noise. These same modifications also allow for a fixed detection threshold, applicable to broadly varying ocean acoustic environments. The detection algorithm is general enough to detect all types of humpback vocalizations. Tests presented in this paper show this algorithm matches human detection performance with an acceptably small probability of false alarms (PFA < 6%) for even the noisiest environments. The detector outperforms energy detection techniques, providing a probability of detection PD = 95% for PFA < 5% for three acoustic deployments, compared to PFA > 40% for two energy-based techniques. The generalized power-law detector also can be used for basic parameter estimation and can be adapted for other types of transient sounds.
Horizontal refraction of propagating sound due to seafloor scours over a range-dependent layered bottom on the New Jersey shelf
Authors: Ballard Megan S. , Lin Ying-Tsong , Lynch James F.
Published: April 2012

Three-dimensional propagation effects of low frequency sound from 100 to 400 Hz caused by seafloor topography and range-dependent bottom structure over a 20 km range along the New Jersey shelf are investigated using a hybrid modeling approach. Normal modes are used in the vertical dimension, and a parabolic-equation approximate model is applied to solve the horizontal refraction equation. Examination of modal amplitudes demonstrates the effect of environmental range dependence on modes trapped in the water column, modes interacting with the bottom, and modes trapped in the bottom. Using normal mode ray tracing, topographic features responsible for three-dimensional effects of horizontal refraction and focusing are identified. These effects are observed in the measurements from the Shallow Water 2006 experiment. Specifically, signals from a pair of fixed sources recorded on a horizontal line array sitting on the seafloor show an intensification caused by horizontal focusing due to the seabed topography of 4 dB along the array.
Energy streamlines for qualitative inverse scattering in fluids and solids
Authors: Aramini R. , Caviglia G. , Piana M.
Published: April 2012

In time-harmonic acoustic fields, energy streamlines are defined as the integral curves of the power-flux density vector, averaged over a period. They provide a tool to visualize the details of propagation of energy. After reviewing the role of energy streamlines in the linear sampling method for acoustic inverse scattering, this work formulates a physical interpretation of the same qualitative method in the case of an isotropic homogeneous solid matrix. Specifically, it is shown that the linear sampling method results from conservation of energy along streamline tubes of energy flow associated with elastic waves.
A blind algorithm for reverberation-time estimation using subband decomposition of speech signals
Authors: Prego Thiago de M. , de Lima Amaro A. , Netto Sergio L. , Lee Bowon , Said Amir , Schafer Ronald W. , Kalker Ton
Published: April 2012

An algorithm for blind estimation of reverberation time (RT) in speech signals is proposed. Analysis is restricted to the free-decaying regions of the signal, where the reverberation effect dominates, yielding a more accurate RT estimate at a reduced computational cost. A spectral decomposition is performed on the reverberant signal and partial RT estimates are determined in all signal subbands, providing more data to the statistical-analysis stage of the algorithm, which yields the final RT estimate. Algorithm performance is assessed using two distinct speech databases, achieving 91% and 97% correlation with the RTs measured by a standard nonblind method, indicating that the proposed method blindly estimates the RT in a reliable and consistent manner.
Stabilization of time domain acoustic boundary element method for the interior problem with impedance boundary conditions
Authors: Jang Hae-Won , Ih Jeong-Guon
Published: April 2012

The time domain boundary element method (BEM) is associated with numerical instability that typically stems from the time marching scheme. In this work, a formulation of time domain BEM is derived to deal with all types of boundary conditions adopting a multi-input, multi-output, infinite impulse response structure. The fitted frequency domain impedance data are converted into a time domain expression as a form of an infinite impulse response filter, which can also invoke a modeling error. In the calculation, the response at each time step is projected onto the wave vector space of natural radiation modes, which can be obtained from the eigensolutions of the single iterative matrix. To stabilize the computation, unstable oscillatory modes are nullified, and the same decay rate is used for two nonoscillatory modes. As a test example, a transient sound field within a partially lined, parallelepiped box is used, within which a point source is excited by an octave band impulse. In comparison with the results of the inverse Fourier transform of a frequency domain BEM, the average of relative difference norm in the stabilized time response is found to be 4.4%.
Audiometric thresholds among a Canadian sample of 10 to 17 year old students
Authors: Marcoux Andre M. , Feder Katya , Keith Stephen E. , Marro Leonora , James Marianne E. , Michaud David S.
Published: April 2012

A total of 237 students, 10 to 17 years of age, from 14 schools underwent hearing evaluations. Otoscopic examination, tympanometry and air-conduction pure tone audiometry was conducted at low (0.5, 1, 2 kHz) and high (4 and 8 kHz) frequencies. In all schools, hearing thresholds were measured with headphones in a portable audiometric booth. Socio-demographic information from students and their parents were collected using questionnaires. Overall, the prevalence of any hearing loss greater than 15 dB was 22.3% for low or high frequency pure tone averages. Self-reported symptoms of hearing loss, such as tinnitus, difficulty following a conversation with background noise, and having to turn up the TV/radio more than in the past, were associated with audiometric thresholds, most notably at 4 kHz. These study findings are among the first to provide a detailed characterization of hearing status in a sample of youth in a Canadian demographic.
The seismic noise wavefield is not diffuse
Authors: Mulargia Francesco
Published: April 2012

Passive seismology is burgeoning under the apparent theoretical support of diffuse acoustics. However, basic physical arguments suggest that this theory may not be applicable to seismic noise. A procedure is developed to establish the applicability of the diffuse field paradigm to a wavefield, based on testing the latter for azimuthal isotropy and spatial homogeneity. This procedure is then applied to the seismic noise recorded at 65 sites covering a wide variety of environmental and subsoil conditions. Considering the instantaneous oscillation vector measured at single triaxial stations, the hypothesis of azimuthal isotropy is rejected in all cases with high confidence, which makes the spatial homogeneity test unnecessary and leads directly to conclude that the seismic noise wavefield is not diffuse. However, such a conclusion has no practical effect on passive imaging, which is also possible in non-diffuse wavefields.
Sequential Bayesian geoacoustic inversion for mobile and compact source-receiver configuration
Authors: Carrière Olivier , Hermand Jean-Pierre
Published: April 2012

Geoacoustic characterization of wide areas through inversion requires easily deployable configurations including free-drifting platforms, underwater gliders and autonomous vehicles, typically performing repeated transmissions during their course. In this paper, the inverse problem is formulated as sequential Bayesian filtering to take advantage of repeated transmission measurements. Nonlinear Kalman filters implement a random-walk model for geometry and environment and an acoustic propagation code in the measurement model. Data from MREA/BP07 sea trials are tested consisting of multitone and frequency-modulated signals (bands: 0.25-0.8 and 0.8-1.6 kHz) received on a shallow vertical array of four hydrophones 5-m spaced drifting over 0.7-1.6 km range. Space- and time-coherent processing are applied to the respective signal types. Kalman filter outputs are compared to a sequence of global optimizations performed independently on each received signal. For both signal types, the sequential approach is more accurate but also more efficient. Due to frequency diversity, the processing of modulated signals produces a more stable tracking. Although an extended Kalman filter provides comparable estimates of the tracked parameters, the ensemble Kalman filter is necessary to properly assess uncertainty. In spite of mild range dependence and simplified bottom model, all tracked geoacoustic parameters are consistent with high-resolution seismic profiling, core logging P-wave velocity, and previous inversion results with fixed geometries.
A single-scattering correction for the seismo-acoustic parabolic equation
Authors: Collins Michael D.
Published: April 2012

An efficient single-scattering correction that does not require iterations is derived and tested for the seismo-acoustic parabolic equation. The approach is applicable to problems involving gradual range dependence in a waveguide with fluid and solid layers, including the key case of a sloping fluid–solid interface. The single-scattering correction is asymptotically equivalent to a special case of a single-scattering correction for problems that only have solid layers [Küsel et al., J. Acoust. Soc. Am. 121, 808–813 (2007)]. The single-scattering correction has a simple interpretation (conservation of interface conditions in an average sense) that facilitated its generalization to problems involving fluid layers. Promising results are obtained for problems in which the ocean bottom interface has a small slope.
The effect of an additional reflection in a precedence effect experiment
Authors: Goupell Matthew J. , Yu Gongqiang , Litovsky Ruth Y.
Published: April 2012

Studies on the precedence effect typically utilize a two-source paradigm, which is not realistic relative to real world situations where multiple reflections exist. A step closer to multiple-reflection situations was studied using a three-source paradigm. Discrimination of interaural time differences (ITDs) was measured for one-, two-, and three-source stimuli, using clicks presented over headphones. The ITD was varied in either the first, second, or the third source. The inter-source intervals ranged from 0–130 ms. A perceptual weighting model was extendedto incorporate the three-source stimuli and used to interpret the data. The effect of adding a third source could mostly, but not entirely, be understood by the interaction of effects observed in the precedence effect with two sources. Specifically, for delays between 1 and 8 ms, the ITD information of prior sources was typically weighted more heavily than subsequent sources. For delays greater than 8 ms, subsequent sources were typically weighted slightly more heavily than prior sources. However, there were specific conditions that showed a more complex interaction between the sources. These findings suggest that the two-source paradigm provides a strong basis for understanding how the auditory system processes reflections in spatial hearing tasks.
Integrating Genomes
Authors: Zerbino D. R. , Paten B. , Haussler D.
Published: April 2012

As genomic sequencing projects attempt ever more ambitious integration of genetic, molecular, and phenotypic information, a specialization of genomics has emerged, embodied in the subdiscipline of computational genomics. Models inherited from population genetics, phylogenetics, and human disease genetics merge with those from graph theory, statistics, signal processing, and computer science to provide a rich quantitative foundation for genomics that can only be realized with the aid of a computer. Unleashed on a rapidly increasing sample of the planet’s 10
30
organisms, these analyses will have an impact on diverse fields of science while providing an extraordinary new window into the story of life.
Topological Transitions in Metamaterials
Authors: Krishnamoorthy Harish N. S. , Jacob Zubin , Narimanov Evgenii , Kretzschmar Ilona , Menon Vinod M.
Published: April 2012

Manipulating Optical Topology

Phase transitions in solid-state systems are often associated with a drastic change in the properties of that system. For example, metal-to-insulator transition or magnetic-to-nonmagnetic states find wide application in memory storage technology. An exotic electronic phase transition is the Lifshitz transition, whereby the Fermi surface undergoes a change in topology and a drastic change in the electronic density of states.

Krishnamoorthy
et al.

(p.
205
) now show that the notion of such a phase transition can be carried over to the optical regime by the suitable design of a metamaterial structure. This effect could be used to control the interaction between light and matter.
Revitalizing Remyelination—the Answer Is Circulating
Authors: Redmond Stephanie A. , Chan Jonah R.
Published: April 2012

Aged oligodendroglia in the mouse central nervous system are competent to repair neural injury when exposed to “youthful” circulatory factors.
F. Sherwood Rowland (1927–2012)
Authors: Cicerone Ralph J. , Molina Mario J. , Blake Donald R.
Published: April 2012

A Nobel Prize–winning atmospheric chemist instrumental in discovering and publicizing the role of chlorofluorocarbons in ozone destruction.
Creativity at the Interface
Authors: Alberts Bruce
Published: April 2012

The biochemistry that makes life possible is based on a complex network of many thousands of interactions between molecules, and it presents an enormous challenge to the scientists trying to understand it. This special issue of
Science
, with its focus on computational biology, demonstrates how mathematics and computer science are being successfully harnessed to tease apart this complexity (see p. 171). But we are only at the very beginning of the process, and it is certain that reaching a true understanding of cells and organisms will require many more contributions from mathematicians, computer scientists, engineers, physicists, and chemists to complement the efforts of biologists. For this reason, graduate schools have become increasingly enthusiastic about recruiting outstanding students with strong backgrounds in these fields to address challenging problems in the biological and biomedical sciences. This is an important trend, except that too often faculty mistakenly assume that learning biology is easy, leaving these very talented young people nearly on their own to acquire the biological wisdom that they will need to explore the many mysteries in living systems. In fact, it is not at all easy to acquire the type of deep understanding of biology that is required to make wise decisions about what is, and what is not, an important problem to investigate; and a successful career in research will require much more than just a union of different expertise and tools.
Ocean's Deep, Dark Trenches to Get Their Moment in the Spotlight
Authors: Lee Jane J.
Published: April 2012

An international group of marine scientists may soon provide a feast of data from the first major systematic study of a deep-sea trench.
LIFE SCIENCE TECHNOLOGIES: Innovation in Japan Results from Reforms
Authors: Tachibana Chris
Published: April 2012

Japanese academic reforms over the last decade have encouraged entrepreneurship and technology transfer from universities to industry. These reforms are now yielding results. Science and business leaders hope these changes push Japan into the next phase of innovation development, with increased flexibility and transparency, a more global focus, and more national and international collaboration. Japanese scientists are ready. After delays caused by the March 2011 triple disaster of earthquake, tsunami, and nuclear power plant failure, the lights are on again in Japanese research laboratories. Although recovery and reconstruction are priorities, the long-term goals of developing sustainable energy sources and solving the health challenges of an aging population continue to be major focus areas.
In Silico
Identification of Epitopes in Mycobacterium avium subsp.
paratuberculosis
Proteins That Were Upregulated under Stress Conditions
Authors: Gurung Ratna B. , Purdie Auriol C. , Begg Douglas J. , Whittington Richard J.
Published: April 2012

Johne's disease in ruminants is caused by
Mycobacterium avium
subsp.
paratuberculosis
. Diagnosis of
M. avium
subsp.
paratuberculosis
infection is difficult, especially in the early stages. To date, ideal antigen candidates are not available for efficient immunization or immunodiagnosis. This study reports the
in silico
selection and subsequent analysis of epitopes of
M. avium
subsp.
paratuberculosis
proteins that were found to be upregulated under stress conditions as a means to identify immunogenic candidate proteins. Previous studies have reported differential regulation of proteins when
M. avium
subsp.
paratuberculosis
is exposed to stressors which induce a response similar to dormancy. Dormancy may be involved in evading host defense mechanisms, and the host may also mount an immune response against these proteins. Twenty-five
M. avium
subsp.
paratuberculosis
proteins that were previously identified as being upregulated under
in vitro
stress conditions were analyzed for B and T cell epitopes by use of the prediction tools at the Immune Epitope Database and Analysis Resource. Major histocompatibility complex class I T cell epitopes were predicted using an artificial neural network method, and class II T cell epitopes were predicted using the consensus method. Conformational B cell epitopes were predicted from the relevant three-dimensional structure template for each protein. Based on the greatest number of predicted epitopes, eight proteins (MAP2698c [encoded by
desA2
], MAP2312c [encoded by
fadE19
], MAP3651c [encoded by
fadE3_2
], MAP2872c [encoded by
fabG5_2
], MAP3523c [encoded by
oxcA
], MAP0187c [encoded by
sodA
], and the hypothetical proteins MAP3567 and MAP1168c) were identified as potential candidates for study of antibody- and cell-mediated immune responses within infected hosts.