bluuebunny/crossref_metadata_2025 huggingface dataset:
The cholinergic blockade of both thermally and non‐thermally induced human eccrine sweating
Authors: Machado‐Moreira Christiano A. , McLennan Peter L. , Lillioja Stephen , van Dijk Wilko , Caldwell Joanne N. , Taylor Nigel A. S.
Published: April 2012

Thermally induced eccrine sweating is cholinergically mediated, but other neurotransmitters have been postulated for psychological (emotional) sweating. However, we hypothesized that such sweating is not noradrenergically driven in passively heated, resting humans. To test this, nine supine subjects were exposed to non‐thermal stimuli (palmar pain, mental arithmetic and static exercise) known to evoke sweating. Trials consisted of the following four sequential phases: thermoneutral rest; passive heating to elevate (by ∼1.0°C) and clamp mean body temperature and steady‐state sweating (perfusion garment and footbath); an atropine sulphate infusion (0.04 mg kg−1) with thermal clamping sustained; and following clamp removal. Sudomotor responses from glabrous (hairless) and non‐glabrous skin surfaces were measured simultaneously (precursor and discharged sweating). When thermoneutral, these non‐thermal stimuli elicited significant sweating only from the palm (P < 0.05). Passive heating induced steady‐state sweating ranging from 0.20 ± 0.04 (volar hand) to 1.40 ± 0.14 mg cm−2 min−1 (forehead), with each non‐thermal stimulus provoking greater secretion (P < 0.05). Atropine suppressed thermal sweating, and it also eliminated the sudomotor responses to these non‐thermal stimuli when body temperatures were prevented from rising (P > 0.05). However, when the thermal clamp was removed, core and skin temperatures became further elevated and sweating was restored (P < 0.05), indicating that the blockade had been overcome, presumably through elevated receptor competition. These observations establish the dependence of both thermal and non‐thermal eccrine sweating from glabrous and non‐glabrous surfaces on acetylcholine release, and challenge theories concerning the psychological modulation of sweating. Furthermore, no evidence existed for the significant participation of non‐cholinergic neurotransmitters during any of these stimulations.
Mixed Lubricated Line Contact Analysis for Spur Gears using a Deterministic Model
Authors: Liu Huaiju , Mao Ken , Zhu Caichao , Xu Xiangyang
Published: April 2012

The unified approach based upon the Reduced Reynolds technique is applied to develop a deterministic transient mixed lubrication line contact model. This model is used in spur gear applications to comprehensively show effects of roughness, working conditions, i.e., rotational speeds and loads on pressure ripples and severity of asperity contacts. Results show effects of the speed, the load, as well as the RMS value are coupled which makes it difficult to evaluate lubrication states by only considering one variable. Considering the Ree-Eyring non-Newtonian behavior could alleviate pressure ripples significantly, compared with the Newtonian fluid assumption. Small RMS values of surfaces, which could be achieved by superfinish techniques, would be desirable when evaluating gear tooth surface contact performances.
Influence of Shearing Surface Topography on Frictional Properties of ZnS Nanowire-Based Lubrication System across Ductile Surfaces
Authors: Kheireddin Bassem A. , Narayanunni Vinay , Akbulut Mustafa
Published: April 2012

This work deals with the effect of surface roughness parameters on the frictional properties of nanowire-based lubrication systems (NBLS) across Cu surfaces with various topographies. The friction coefficient was discussed in the context of surface roughness parameters including the rms height, inter-island separation and a combined roughness parameter related to the pressure experienced by each nanowire. It was concluded that the rms height of asperity should not be lower than the radius of nanoparticles for effective lubrication. In addition, when the inter-island separation is an integer multiple of the nanowire length, nanowires perform as effective lubricants. Furthermore, the friction coefficient increased when the mean pressure experienced by the nanowires increased. The results obtained in this original study offer some interesting insights into the frictional properties of NBLS as a function of surface roughness parameters. This could lead to a great impact on the selection of nanoparticle-based lubricant aimed at reducing wear and energy losses for various applications.
Reduction of Combustion Gases’ Temperature and Heating Capacity by CO2 and H2O Dissociation and NO Formation
Authors: Flores Leonardo , Cervantes de Gortari Jaime
Published: April 2012

The combustion gases theoretical adiabatic temperatures are reduced to equilibrium temperatures mainly because of the endothermic reactions of CO2 and H2O dissociation and NO formation. Therefore, the heating capacity of the gases is reduced to the equilibrium gases enthalpy. In the paper, these reactions and the way to consider them to calculate the gases’ final equilibrium are exemplified, covering an ample range of temperatures. It is shown the method sensitivity and the results are verified against some registered values. The procedure allows calculation of the NO formation, evidencing its increment with the temperature. The reductions in combustion gases’ adiabatic temperature and heating capacity are proportional to the theoretical adiabatic combustion temperature, apparent when the respective percentage decrements go from 2.2 and 2.7 at 2224 K to 46.8 and 50.9 at 7427 K for the studied combustion systems. This trend points out some maximum temperature reachable by oxidation, possibly 6000 K-the approximate energy emission sun temperature.
Oxidative Activity of Hydrogen on Nickel and Inconel
Authors: Urness Kimberly N. , Ellison G. Barney , Daily John W.
Published: April 2012

Experiments were carried out to determine whether nickel or Inconel are catalytically active for hydrogen oxidation. The work was motivated by the problem of flame flashback and/or inlet preignition in hydrogen-rich syngas fueled premixed/prevaporized gas turbine combustors. The experiments were performed using small resistively heated tubular reactors with matrix isolation/infrared diagnostics. Reactors were manufactured from stainless steel, nickel and Inconel. For the flow conditions studied, the conversion efficiency was about 3% for the nickel reactor and 0.9% for the Inconel reactor. No activity was seen for stainless steel. Comparison with a published surface kinetic reaction mechanism for nickel suggests that the surface oxidation rate of H2 in our reactors is about two orders of magnitude less than for specially prepared surfaces.
Diesel Injector Coking: Optical-Chemical Analysis of Deposits and Influence on Injected Flow-Rate, Fuel Spray and Engine Performance
Authors: d’Ambrosio S. , Ferrari A.
Published: April 2012

The physical origin of injector coking in diesel engines has been clarified and the most critical design parameters and operating variables pertaining to the occurrence of the phenomenon have been identified. Fouling has been shown to be affected by many factors, such as injector temperature, nozzle configuration, hole diameter and conicity as well as fuel composition. Optical and scanning electron microscope (SEM) analyses have been conducted both inside and outside injectors of different type and four locations have been identified as the main deposition sites. Furthermore, different coking typologies, i.e., dry and wet coking, have been assessed and discussed. Energy Dispersive X-ray (EDX) spectroscopy images of the deposits on the spray hole walls have revealed that minute quantities of Zn catalyze the coking reactions to a great extent. Significant quantities of Zn have also been found in the injector deposits. An extensive experimental test campaign has been carried out at the engine test bench with different nozzle setups in order to evaluate performance deterioration after different ageing procedures. The effects of both the Zn concentration in the fuel and running time have been assessed separately on the fouling rate. Injection rate time histories have been acquired at the hydraulic test rig, under different working conditions, for both new and aged injectors. The experimental changes in the EVI profiles subsequent to fouling have been analyzed and related to the corresponding variations in engine power measured at the engine test bench. A previously developed combustion multi-zone diagnostic model has also been applied to gain a further insight into the cause and effect relationships between the experimental in-cylinder pressure time histories and engine-out emissions.
A Study of the Effects of Biofuel Use on Piston Lubrication During Fuel Post Injection in a Direct Injection Diesel Engine
Authors: Kikuhara Koji , Shibata Akihiro , Ito Akemi , Kim Dallwoo , Ishikawa Yasuhiro , Usui Miyuki
Published: April 2012

The reduction of both exhaust gases and carbon dioxide emissions is necessary to meet future emissions regulations for diesel engines. Exhaust after-treatment devices are gradually being applied to diesel engines to reduce exhaust gases. Diesel particulate filters (DPF), an after-treatment device for diesel engines, in some cases require fuel post injection for regeneration. Post injection is usually conducted at the midpoint of the expansion stroke, and therefore causes fuel adhesion to the cylinder wall. However, using biofuels in a diesel engine is an effective way of reducing carbon dioxide emissions. It is well known that biofuels are chemically unstable, but the effects of biofuels on piston lubrication condition have not been thoroughly studied. In this study, piston lubrication condition during post injection in a single cylinder DI diesel engine using biofuel was investigated. Piston and ring friction forces were measured under engine operating conditions by means of a floating liner device to investigate the lubrication condition of the piston and rings. Both light fuel oil and biofuel were used in the measurements, with rapeseed methyl ester (RME) being used as the biofuel. Lubricating oil on the cylinder wall was also sampled under engine operating conditions, and the effect of post injection on fuel adhesion to the cylinder wall was analyzed. It was found that the effect of post injection on fuel adhesion to the cylinder wall was remarkable around the top dead center (TDC), and the fuel dilution rate reached approximately 90%. The results of the measurement of the piston friction forces showed that post injection caused an increase in the friction forces at the compression TDC (CTDC) in the cases of both RME and light fuel oil, and the friction forces at CTDC increased according to the delay of the post injection timing. The increase in the piston friction forces was moderate in the case of RME. It seems that the higher viscosity and the oiliness of RME suppressed the increase in piston friction forces at TDC. The following effects were found in this study. Fuel post injection caused fuel adhesion to the cylinder wall. Such phenomena affected the lubrication condition of the piston. In the case of RME, the increase in the piston friction forces caused by post injection was smaller than that of light fuel oil, but the effects on piston lubrication condition in the case of using other biofuels needs to be investigated.
Effects of Gas Rarefaction on Dynamic Characteristics of Micro Spiral-Grooved Thrust Bearing
Authors: Liu Ren , Wang Xiao-Li , Zhang Xiao-Qing
Published: April 2012

The effects of gas-rarefaction on dynamic characteristics of micro spiral-grooved-thrust-bearing are studied. The Reynolds equation is modified by the first order slip model, and the corresponding perturbation equations are then obtained on the basis of the linear small perturbation method. In the converted spiral-curve-coordinates system, the finite-volume-method (FVM) is employed to discrete the surface domain of micro bearing. The results show, compared with the continuum-flow model, that under the slip-flow regime, the decrease in the pressure and stiffness become obvious with the increasing of the compressibility number. Moreover, with the decrease of the relative gas-film-thickness, the deviations of dynamic coefficients between slip-flow-model and continuum-flow-model are increasing.
Visibility of microcalcification clusters and masses in breast tomosynthesis image volumes and digital mammography: A 4AFC human observer study
Authors: Timberg P. , Båth M. , Andersson I. , Mattsson S. , Tingberg A. , Ruschin M.
Published: April 2012

Purpose

: To investigate the visibility of simulated lesions in digital breast tomosynthesis (BT) image volumes compared with 2D digital mammography (DM).

Methods

: Simulated lesions (masses and microcalcifications) were added to images of the same women acquired on a DM system (Mammomat Novation, Siemens) and a BT prototype. The same beam quality was used for the DM and BT acquisitions. The total absorbed dose resulting from a 25‐projection BT acquisition and reconstruction (BT25) was approximately twice that of a single DM view. By excluding every other projection image from the reconstruction (BT13), approximately the same dose as in DM was effected. Simulated microcalcifications were digitally added with varying contrast to the DM and BT images. Simulated masses with 8 mm diameter were also added to BT images. A series of 4‐alternative forced choice (4AFC) human observer experiments were conducted. Four medical physicists participated in all experiments, each consisting of 60 trials per experimental condition. The observers interpreted the BT image volumes in cine‐mode at a fixed image sequence speed. The required threshold contrast (St) to achieve a detectability index (d′) of 2.5 (i.e., 92.5% correct decisions) was determined.

Results

: The St for mass detection in DM was approximately a factor of 2 higher than required in BT indicating that the detection of masses was improved under BT conditions compared to DM. St for microcalcification detection was higher for BT than for DM at both BT dose levels (BT25 and BT13), with a statistically significant difference in St between DM and BT13. These results indicate a dose‐dependent decrease in detection performance in BT for detection of microcalcifications.

Conclusions

: In agreement with previous investigations, masses of size 8 mm can be detected with less contrast in BT than in DM indicating improved detection performance for BT. However, for the investigated microcalcifications, the results of this study indicate potentially worse performance for BT than for DM at the same dose level.
Breast radiotherapy in the prone position primarily reduces the maximum out‐of‐field measured dose to the ipsilateral lung
Authors: Becker Stewart J. , Elliston Carl , DeWyngaert Keith , Jozsef Gabor , Brenner David , Formenti Silvia
Published: April 2012

Purpose:

To quantify the potential advantages of prone position breast radiotherapy in terms of the radiation exposure to out‐of‐field organs, particularly, the breast or the lung. Several dosimetric studies have been reported, based on commercial treatment planning software (TPS). These TPS approaches are not, however, adequate for characterizing out‐of‐field doses. In this work, relevant out‐of‐field organ doses have been directly measured.

Methods:

The authors utilized an adult anthropomorphic phantom to conduct measurements of out‐of‐field doses in prone and supine position, using 50 Gy prescription dose intensity modulated radiation therapy (IMRT) and 3D‐CRT plans. Measurements were made using multiple MOSFET dosimeters in various locations in the ipsilateral lung, the contralateral lung and in the contralateral breast.

Results:

The closer the organ (or organ segment) was to the treatment volume, the more dose sparing was seen for prone vs supine positioning. Breast radiotherapy in the prone position results in a marked reduction in the dose to the proximal part of the ipsilateral lung, compared with treatment in the conventional supine position. This is true both for 3D‐CRT and for IMRT. For IMRT, the maximum measured dose to the lung was reduced from 4 to 1.6 Gy, while for 3D‐CRT, the maximum measured lung dose was reduced from 5 to 1.7 Gy. For the proximal part of the ipsilateral lung, as well as for the contralateral lung and the contralateral breast, there is little difference in the measured organ doses whether the treatment is given in the prone or the supine‐position.

Conclusions:

The decrease in the maximum dose to the proximal part of the ipsilateral lung produced by prone position radiotherapy is of potentially considerable significance. The dose‐response relation for radiation‐induced lung cancer increases monotonically in the zero to 5‐Gy dose range, implying that a major decrease in the maximum lung dose may result in a significant decrease in the radiation‐induced lung cancer risk.
The Shadow Knows: Inferring the Density Distribution of a Nonuniform Medium from its Standing Wave Pattern
Authors: Binder Philippe , Cunnyngham Ian
Published: April 2012

In a recent note in this journal,1 Gluck presents a beautiful demonstration of the standing wave generated by a strip of material with linearly varying width (a trapezoid). As expected, the resulting wave envelope (and its shadow) showed a varying wavelength—smaller as the strip width gets larger.
Teaching Quantum Nonlocality
Authors: Hobson Art
Published: April 2012

Nonlocality arises from the unified “all or nothing” interactions of a spatially extended field quantum such as a photon or an electron.2 In the double-slit experiment with light, for example, each photon comes through both slits and arrives at the viewing screen as an extended but unified energy bundle or “field quantum.” When the photon interacts (randomly2) with the screen, field quantization requires it to alter its state instantaneously rather than gradually. Thus if the photon is absorbed, it must vanish or “collapse” nonlocally and instantaneously across a macroscopic portion of the screen, even across many kilometers in the case of interference patterns of light from a small distant star. The interaction instantly transfers the photons energy to a single atom of the screen. But a quantized field can contain any whole number of “excitations” (particles such as photons or electrons). If a single field quantum contains, say, two excitations, then generally the unified all-or-nothing character of quanta implies that any interaction of one excitation must also instantaneously affect the other excitation, regardless of the distance between them. The particles are then said to be “entangled” (see the “Background” section for a more precise definition of this term). Particles can become entangled by being created together in a single microscopic process, or by interacting with each other. Quantum entanglement is at least as fundamental as quantum uncertainty but is seldom mentioned in physics courses, although it has received broad attention recently in a wonderful book by Louisa Gilder.3 A recent paper in this journal presents entanglement in a manner that is useful for high school and college physics teachers.4 This paper builds on that presentation and looks at a different, more intuitive entanglement experiment that should be accessible to both scientists and nonscientists.
Characterization of woodwind instrument toneholes with the finite element method
Authors: Lefebvre Antoine , Scavone Gary P.
Published: April 2012

A method is proposed to determine the transfer matrix parameters of a discontinuity in a waveguide with the finite element method (FEM). This is used to characterize open and closed woodwind instrument toneholes and develop expressions for the shunt and series equivalent lengths. Two types of toneholes are characterized: Unflanged toneholes made of thin material, such as found on saxophones and concert flutes, and toneholes drilled through a thick material, such as found on most instruments made of wood. The results are compared with previous tonehole models from the literature. In general, the proposed expressions provide a better fit across a wide range of frequencies and tonehole sizes than previous results. For tall toneholes, the results are in general agreement with previous models. For shorter tonehole heights, some discrepancies from previous results are found that are most important for larger diameter toneholes. Finally, the impact of a main bore taper (conicity) on the characterization of toneholes was investigated and found to be negligible for taper angles common in musical instruments.
Localization of distinct reflections in rooms using spherical microphone array eigenbeam processing
Authors: Sun Haohai , Mabande Edwin , Kowalczyk Konrad , Kellermann Walter
Published: April 2012

This paper presents an experimental and comparative study of several spherical microphone array eigenbeam (EB) processing techniques for localization of early reflections in room acoustic environments, which is a relevant research topic in both audio signal processing and room acoustics. This paper focuses on steered beamformer-based and subspace-based localization techniques implemented in the spherical EB domain, including the plane-wave decomposition, eigenbeam delay and sum, eigenbeam minimum variance distortionless response, eigenbeam multiple signal classification (EB-MUSIC), and eigenbeam estimation of signal parameters via rotational invariance techniques (EB-ESPRIT) methods. The directions of arrival of the original sound source and the associated reflection signals in acoustic environments are estimated from acoustic maps of the rooms, which are obtained using a spherical microphone array. The EB-domain-based frequency smoothing and white noise gain control techniques are derived and employed to improve the performance and robustness of reflection localization. The applicability of the presented methods in practice is confirmed by experiments carried out in real rooms.
Characteristics of gunshot sound displays by North Atlantic right whales in the Bay of Fundy
Authors: Parks Susan E. , Hotchkin Cara F. , Cortopassi Kathryn A. , Clark Christopher W.
Published: April 2012

North Atlantic right whales (Eubalaena glacialis) produce a loud, broadband signal referred to as the gunshot sound. These distinctive sounds may be suitable for passive acoustic monitoring and detection of right whales; however, little is known about the prevalence of these sounds in important right whale habitats, such as the Bay of Fundy. This study investigates the timing and distribution of gunshot sound production on the summer feeding grounds using an array of five marine acoustic recording units deployed in the Bay of Fundy, Canada in mid-summer 2004 and 2005. Gunshot sounds were common, detected on 37 of 38 recording days. Stereotyped gunshot bouts averaged 1.5 h, with some bouts exceeding 7 h in duration with up to seven individuals producing gunshots at any one time. Bouts were more commonly detected in the late afternoon and evening than during the morning hours. Locations of gunshots in bouts indicated that whales producing the sounds were either stationary or showed directional travel, suggesting gunshots have different communication functions depending on behavioral context. These results indicate that gunshots are a common right whale sound produced during the summer months and are an important component in the acoustic communication system of this endangered species.
Informational masking of speech produced by speech-like sounds without linguistic content
Authors: Chen Jing , Li Huahui , Li Liang , Wu Xihong , Moore Brian C. J.
Published: April 2012

This study investigated whether speech-like maskers without linguistic content produce informational masking of speech. The target stimuli were nonsense Chinese Mandarin sentences. In experiment I, the masker contained harmonics the fundamental frequency (F0) of which was sinusoidally modulated and the mean F0 of which was varied. The magnitude of informational masking was evaluated by measuring the change in intelligibility (releasing effect) produced by inducing a perceived spatial separation of the target speech and masker via the precedence effect. The releasing effect was small and was only clear when the target and masker had the same mean F0, suggesting that informational masking was small. Performance with the harmonic maskers was better than with a steady speech-shaped noise (SSN) masker. In experiments II and III, the maskers were speech-like synthesized signals, alternating between segments with harmonic structure and segments composed of SSN. Performance was much worse than for experiment I, and worse than when an SSN masker was used, suggesting that substantial informational masking occurred. The similarity of the F0 contours of the target and masker had little effect. The informational masking effect was not influenced by whether or not the noise-like segments of the masker were synchronous with the unvoiced segments of the target speech.
The interrelation between acoustic context effects and available response categories in speech sound categorization
Authors: Benders Titia , Escudero Paola , Sjerps Matthias J.
Published: April 2012

In an investigation of contextual influences on sound categorization, 64 Peruvian Spanish listeners categorized vowels on an /i/ to /e/ continuum. First, to measure the influence of the stimulus range (broad acoustic context) and the preceding stimuli (local acoustic context), listeners were presented with different subsets of the Spanish /i/-/e/ continuum in separate blocks. Second, the influence of the number of response categories was measured by presenting half of the participants with /i/ and /e/ as responses, and the other half with /i/, /e/, /a/, /o/, and /u/. The results showed that the perceptual category boundary between /i/ and /e/ shifted depending on the stimulus range and that the formant values of locally preceding items had a contrastive influence. Categorization was less susceptible to broad and local acoustic context effects, however, when listeners were presented with five rather than two response options. Vowel categorization depends not only on the acoustic properties of the target stimulus, but also on its broad and local acoustic context. The influence of such context is in turn affected by the number of internal referents that are available to the listener in a task.
Relating binaural pitch perception to the individual listener’s auditory profile
Authors: Santurette Sébastien , Dau Torsten
Published: April 2012

The ability of eight normal-hearing listeners and fourteen listeners with sensorineural hearing loss to detect and identify pitch contours was measured for binaural-pitch stimuli and salience-matched monaurally detectable pitches. In an effort to determine whether impaired binaural pitch perception was linked to a specific deficit, the auditory profiles of the individual listeners were characterized using measures of loudness perception, cognitive ability, binaural processing, temporal fine structure processing, and frequency selectivity, in addition to common audiometric measures. Two of the listeners were found not to perceive binaural pitch at all, despite a clear detection of monaural pitch. While both binaural and monaural pitches were detectable by all other listeners, identification scores were significantly lower for binaural than for monaural pitch. A total absence of binaural pitch sensation coexisted with a loss of a binaural signal-detection advantage in noise, without implying reduced cognitive function. Auditory filter bandwidths did not correlate with the difference in pitch identification scores between binaural and monaural pitches. However, subjects with impaired binaural pitch perception showed deficits in temporal fine structure processing. Whether the observed deficits stemmed from peripheral or central mechanisms could not be resolved here, but the present findings may be useful for hearing loss characterization.
Adaptive control of contrast agent microbubbles for shell parameter identification
Authors: Dadok Vera , Szeri Andrew J.
Published: April 2012

An adaptive controller design is proposed and simulated for parameter identification and oscillation control in microbubble systems. Lyapunov’s direct method and a Lyapunov-like analysis are used to show stability and convergence of trajectory tracking and parameter adaptation. The method allows for the determination of microbubble contrast agent shell thickness or material parameters in a nondestructive manner.
Effect of enhancement of spectral changes on speech intelligibility and clarity preferences for the hearing impaired
Authors: Chen Jing , Baer Thomas , Moore Brian C. J.
Published: April 2012

Most information in speech is carried in spectral changes over time, rather than in static spectral shape per se. A form of signal processing aimed at enhancing spectral changes over time was developed and evaluated using hearing-impaired listeners. The signal processing was based on the overlap-add method, and the degree and type of enhancement could be manipulated via four parameters. Two experiments were conducted to assess speech intelligibility and clarity preferences. Three sets of parameter values (one corresponding to a control condition), two types of masker (steady speech-spectrum noise and two-talker speech) and two signal-to-masker ratios (SMRs) were used for each masker type. Generally, the effects of the processing were small, although intelligibility was improved by about 8 percentage points relative to the control condition for one set of parameter values using the steady noise masker at −6 dB SMR. The processed signals were not preferred over those for the control condition, except for the steady noise masker at −6 dB SMR. Further work is needed to determine whether tailoring the processing to the characteristics of the individual hearing-impaired listener is beneficial.
Binaural temporal fine structure sensitivity, cognitive function, and spatial speech recognition of hearing-impaired listeners (L)
Authors: Neher Tobias , Lunner Thomas , Hopkins Kathryn , Moore Brian C. J.
Published: April 2012

The relationships between spatial speech recognition (SSR; the ability to understand speech in complex spatial environments), binaural temporal fine structure (TFS) sensitivity, and three cognitive tasks were assessed for 17 hearing-impaired listeners. Correlations were observed between SSR, TFS sensitivity, and two of the three cognitive tasks, which became non-significant when age effects were controlled for, suggesting that reduced TFS sensitivity and certain cognitive deficits may share a common age-related cause. The third cognitive measure was also significantly correlated with SSR, but not with TFS sensitivity or age, suggesting an independent non-age-related cause.
Relationship between visual counts and call detection rates of gray whales (Eschrichtius robustus) in Laguna San Ignacio, Mexico
Authors: Ponce Diana , Thode Aaron M. , Guerra Melania , Urbán R. Jorge , Swartz Steven
Published: April 2012

Daily acoustic calling rates of Eastern North Pacific (ENP) gray whales were measured on 6 days during 1 mo of their 2008 breeding season in the sheltered coastal lagoon of Laguna San Ignacio in Baja California, Mexico. Visual counts of whales determined that the numbers of single animals in the lower lagoon more than tripled over the observation period. All call types showed production peaks in the early morning and evening with minimum rates generally detected in the early afternoon. For four of the five observation days, the daily number of “S1”-type calls increased roughly as the square of the number of the animals in the lower lagoon during both daytime and nighttime. This relationship persisted when raw call counts were adjusted for variations in background noise level, using a simple propagation law derived from empirical measurements. The one observation day that did not fit the square-law relationship occurred during a week when the group size in the lagoon increased rapidly. These results suggest that passive acoustic monitoring does not measure gray whale group size directly but monitors the number of connections in the social network, which rises as roughly M2/2 for a group size M.
Sensitivity of school-aged children to pitch-related cues
Authors: Deroche Mickael L. D. , Zion Danielle J. , Schurman Jaclyn R. , Chatterjee Monita
Published: April 2012

Two experiments investigated the ability of 17 school-aged children to process purely temporal and spectro-temporal cues that signal changes in pitch. Percentage correct was measured for the discrimination of sinusoidal amplitude modulation rate (AMR) of broadband noise in experiment 1 and for the discrimination of fundamental frequency (F0) of broadband sine-phase harmonic complexes in experiment 2. The reference AMR was 100 Hz as was the reference F0. A child-friendly interface helped listeners to remain attentive to the task. Data were fitted using a maximum-likelihood technique that extracted threshold, slope, and lapse rate. All thresholds were subsequently standardized to a common d′ value equal to 0.77. There were relatively large individual differences across listeners: eight had relatively adult-like thresholds in both tasks and nine had higher thresholds. However, these individual differences did not vary systematically with age, over the span of 6–16 yr. Thresholds were correlated across the two tasks and were about nine times finer for F0 discrimination than for AMR discrimination as has been previously observed in adults.
Scattering of time-harmonic elastic waves by an elastic inclusion with quadratic nonlinearity
Authors: Tang Guangxin , Jacobs Laurence J. , Qu Jianmin
Published: April 2012

This paper considers the scattering of a plane, time-harmonic wave by an inclusion with heterogeneous nonlinear elastic properties embedded in an otherwise homogeneous linear elastic solid. When the inclusion and the surrounding matrix are both isotropic, the scattered second harmonic fields are obtained in terms of the Green’s function of the surrounding medium. It is found that the second harmonic fields depend on two independent acoustic nonlinearity parameters related to the third order elastic constants. Solutions are also obtained when these two acoustic nonlinearity parameters are given as spatially random functions. An inverse procedure is developed to obtain the statistics of these two random functions from the measured forward and backscattered second harmonic fields.
An acoustic system for the individual recognition of insects
Authors: Zhang Bo , Cheng Jinkui , Han Yan , Ji Liqiang , Shi Fuming
Published: April 2012

Research into acoustic recognition systems for insects has focused on species identification rather than individual identification. In this paper, the feasibility of applying pattern recognition techniques to construct an acoustic system capable of automatic individual recognition for insects is investigated analytically and experimentally across two species of Orthoptera. Mel-frequency cepstral coefficients serve as the acoustic feature, and α-Gaussian mixture models were selected as the classification models. The performance of the proposed acoustic system is promising and displays high accuracy. The results suggest that the acoustic feature and classifier method developed here have potential for individual animal recognition and can be applied to other species of interest.
Dialect experience and perceptual integrality in phonological registers: Fundamental frequency, voice quality and the first formant in Cham
Authors: Brunelle Marc
Published: April 2012

The perceptual integrality of f0, F1 and voice quality is investigated by looking at register, a phonological contrast that relies on these three properties in three dialects of Cham, an Austronesian language of Mainland Southeast Asia. The results of a Garner classification experiment confirm that the three acoustic properties integrate perceptually and that their patterns of integrality are similar in the three dialects. Moreover, they show that dialect-specific sensitivity to acoustic properties can cause salient dimensions to override weaker ones. Finally, the patterns of integrality found in Cham suggest that auditory integrality is not limited to acoustically similar properties.
The influence of non-spatial factors on measures of spatial release from masking
Authors: Best Virginia , Marrone Nicole , Mason Christine R. , Kidd Gerald
Published: April 2012

This study tested the hypothesis that the reduction in spatial release from masking (SRM) resulting from sensorineural hearing loss in competing speech mixtures is influenced by the characteristics of the interfering speech. A frontal speech target was presented simultaneously with two intelligible or two time-reversed (unintelligible) speech maskers that were either colocated with the target or were symmetrically separated from the target in the horizontal plane. The difference in SRM between listeners with hearing impairment and listeners with normal hearing was substantially larger for the forward maskers (deficit of 5.8 dB) than for the reversed maskers (deficit of 1.6 dB). This was driven by the fact that all listeners, regardless of hearing abilities, performed similarly (and poorly) in the colocated condition with intelligible maskers. The same conditions were then tested in listeners with normal hearing using headphone stimuli that were degraded by noise vocoding. Reducing the number of available spectral channels systematically reduced the measured SRM, and again, more so for forward (reduction of 3.8 dB) than for reversed speech maskers (reduction of 1.8 dB). The results suggest that non-spatial factors can strongly influence both the magnitude of SRM and the apparent deficit in SRM for listeners with impaired hearing.
Observation of Skyrmions in a Multiferroic Material
Authors: Seki S. , Yu X. Z. , Ishiwata S. , Tokura Y.
Published: April 2012

Harnessing the Magnetoelectric Effect

Some multiferroic materials exhibit the so-called magnetoelectric effect, in which an external magnetic field can cause electric polarization and an electric field can cause magnetic order. This is important because the manipulation of magnetic structures by electric means is technologically highly desirable.

Seki
et al.

(p.
198
) discovered spin whirlpools called skyrmions in the multiferroic material Cu
2
OSeO
3
and observed a magnetoelectric coupling exerted by the skyrmions. The existence of skyrmions in an insulating magnetoelectric material holds promise for their future manipulation.
Mechanism of Voltage Gating in Potassium Channels
Authors: Jensen Morten Ø. , Jogini Vishwanath , Borhani David W. , Leffler Abba E. , Dror Ron O. , Shaw David E.
Published: April 2012

Open and Shut Case

Voltage-sensing domains (VSDs) control the activity of voltage-gated ion channels to regulate the ion flow that underlies nerve conduction. Structural and biophysical studies have provided insight into voltage gating; however, understanding has been hindered by the lack of a crystal structure of a fully closed state. Starting from a structure of an open conducting state, a voltage-gated K
+
channel,

Jensen
et al.

(p.
229
) used all-atom molecular dynamics simulations to show the conformational changes involved in switching to the closed, nonconducting state. Additional simulations revealed the major steps of channel activation. The computational determination of a closed state may guide development of drugs to treat channelopathies associated with this resting state.
Ferroelectric Columnar Liquid Crystal Featuring Confined Polar Groups Within Core–Shell Architecture
Authors: Miyajima Daigo , Araoka Fumito , Takezoe Hideo , Kim Jungeun , Kato Kenichi , Takata Masaki , Aida Takuzo
Published: April 2012

Finessing Ferroelectric Liquid Crystals

For a material to show a ferroelectric response, it needs to have segments that can be polarized, with a net polarization that remains when the applied field is removed. However, the fluidity that allows liquid crystal molecules to easily move under an applied force also makes it hard to create a ferroelectric response.

Miyajima
et al.

(p.
209
) show that a set of columnar liquid crystal molecules, with polar cyano groups tethered to amide-capped nonpolar chains, can assemble into an umbrella-shaped core–shell architecture, in which hydrogen bonding among the amides keeps the cyano groups confined. With only subtle variations in the tether chemistry, the assemblies can be tuned from having a para-electric to a ferroelectric response, which requires only a small coercive field.
Shining Light into Black Boxes
Authors: Morin A. , Urban J. , Adams P. D. , Foster I. , Sali A. , Baker D. , Sliz P.
Published: April 2012

Funders, publishers, and research institutions must act to ensure that research computer code is made widely available.
Dusting Off the Turing Test
Authors: French Robert M.
Published: April 2012

Revolutionary advances in data capture, storage, retrieval, and analysis revive questions raised by the Turing test.
Wiping Drug Memories
Authors: Milton Amy L. , Everitt Barry J.
Published: April 2012

A nonpharmacological approach alters the memory of drug exposure in rats and has implications for treating relapse in human addicts.
ESCRTing DNA at the Cleavage Site During Cytokinesis
Authors: Petronczki Mark , Uhlmann Frank
Published: April 2012

During cell division, Aurora B prevents collisions between chromatin and the cytokinetic apparatus by targeting the ESCRT-III subunit CHMP4C.
Research Cuts Will Cause ‘Exodus’ From Spain
Authors: Pain Elisabeth
Published: April 2012

Last week's announcement that the long-delayed 2012 national budget would slash funding for science by more than 25% surpassed the worst predictions of Spanish scientists.
Greece Eyes CERN, ESA Cuts to Plug Budget Gap
Authors: Cartlidge Edwin
Published: April 2012

To plug a €10 million hole in its science budget while avoiding the closure of domestic research centers, Greece has begun renegotiating its subscriptions to and memberships in international organizations.
Mystery Disease Haunts Region
Authors: Vogel Gretchen
Published: April 2012

Could the parasite behind onchocerciasis, better known as river blindness, also explain the odd “nodding” seizures in a growing number of African children?
Sparks Fly Over Shoestring Test Of ‘Holographic Principle’
Authors: Cho Adrian
Published: April 2012

A team of physicists says it can use lasers to see whether the universe stores information like a hologram. But some key theorists think the test won't fly.
Tougher Times for Any Life on an Early Mars?
Authors: Kerr Richard A.
Published: April 2012

In the meeting's sole plenary lecture, a planetary geologist marched back in martian time to argue that Mars has always been cold and dry.
Snapshots From the Meeting
Authors: Kerr Richard A.
Published: April 2012

Snapshots from the meeting include martian features that behave just like areas of Antarctica that are known to be wet and evidence that the LCROSS lunar impacter most likely struck a particularly wet spot by chance.
The Young Solar System Took a One-Two Punch?
Authors: Kerr Richard A.
Published: April 2012

A planetary dynamicist suggested that those who believe the early geologic record reflects the solar system's violent birth pangs and those who see evidence of a "late heavy bombardment" might both be partly right.
Virtual Hot Spots
Authors: Pennisi Elizabeth
Published: April 2012

Physiological ecologists who design computer models to predict how animals handle heat are forecasting the effects of climate change.
Japanese Reference Panel of Blood Specimens for Evaluation of Hepatitis C Virus RNA and Core Antigen Quantitative Assays
Authors: Murayama Asako , Sugiyama Nao , Watashi Koichi , Masaki Takahiro , Suzuki Ryosuke , Aizaki Hideki , Mizuochi Toshiaki , Wakita Takaji , Kato Takanobu
Published: April 2012

An accurate and reliable quantitative assay for hepatitis C virus (HCV) is essential for measuring viral propagation and the efficacy of antiviral therapy. There is a growing need for domestic reference panels for evaluation of clinical assay kits because the performance of these kits may vary with region-specific genotypes or polymorphisms. In this study, we established a reference panel by selecting 80 donated blood specimens in Japan that tested positive for HCV. Using this panel, we quantified HCV viral loads using two HCV RNA kits and five core antigen (Ag) kits currently available in Japan. The data from the two HCV RNA assay kits showed excellent correlation. All RNA titers were distributed evenly across a range from 3 to 7 log IU/ml. Although the data from the five core Ag kits also correlated with RNA titers, the sensitivities of individual kits were not sufficient to quantify viral load in all samples. As calculated by the correlation with RNA titers, the theoretical lower limits of detection by these core Ag assays were higher than those for the detection of RNA. Moreover, in several samples in our panel, core Ag levels were underestimated compared to RNA titers. Sequence analysis in the HCV core region suggested that polymorphisms at amino acids 47 to 49 of the core Ag were responsible for this underestimation. The panel established in this study will be useful for estimating the quality of currently available and upcoming HCV assay kits; such quality control is essential for clinical usage of these kits.
Proteomic Profiling of EBNA1-Host Protein Interactions in Latent and Lytic Epstein-Barr Virus Infections
Authors: Malik-Soni Natasha , Frappier Lori
Published: April 2012

The Epstein-Barr nuclear antigen 1 (EBNA1) protein of Epstein-Barr virus (EBV) is expressed in both latent and lytic modes of EBV infection and contributes to EBV-associated cancers. Using a proteomics approach, we profiled EBNA1-host protein interactions in nasopharyngeal and gastric carcinoma cells in the context of latent and lytic EBV infection. We identified several interactions that occur in both modes of infection, including a previously unreported interaction with nucleophosmin and RNA-mediated interactions with several heterogeneous ribonucleoproteins (hnRNPs) and La protein.
Endothelial Cells Elicit Immune-Enhancing Responses to Dengue Virus Infection
Authors: Dalrymple Nadine A. , Mackow Erich R.
Published: April 2012

Dengue viruses cause two severe diseases that alter vascular fluid barrier functions, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Preexisting antibodies to dengue virus disposes patients to immune-enhanced edema (DSS) or hemorrhagic (DHF) disease following infection by a discrete dengue virus serotype. Although the endothelium is the primary vascular fluid barrier, direct effects of dengue virus on endothelial cells (ECs) have not been considered primary factors in pathogenesis. Here, we show that dengue virus infection of human ECs elicits immune-enhancing EC responses. Our results suggest that rapid early dengue virus proliferation within ECs is permitted by dengue virus regulation of early, but not late, beta interferon (IFN-β) responses. The analysis of EC responses following synchronous dengue virus infection revealed the high-level induction and secretion of immune cells (T cells, B cells, and mast cells) as well as activating and recruiting cytokines BAFF (119-fold), IL-6/8 (4- to 7-fold), CXCL9/10/11 (45- to 338-fold), RANTES (724-fold), and interleukin-7 (IL-7; 128-fold). Moreover, we found that properdin factor B, an alternative pathway complement activator that directs chemotactic anaphylatoxin C3a and C5a production, was induced 34-fold. Thus, dengue virus-infected ECs evoke key inflammatory responses observed in dengue virus patients which are linked to DHF and DSS. Our findings suggest that dengue virus-infected ECs directly contribute to immune enhancement, capillary permeability, viremia, and immune targeting of the endothelium. These data implicate EC responses in dengue virus pathogenesis and further rationalize therapeutic targeting of the endothelium as a means of reducing the severity of dengue virus disease.