bluuebunny/crossref_metadata_2025 huggingface dataset:
Salvage therapy of refractory severe aplastic anemia by decreasing cyclosporine dose regimen
Authors: Bertrand Amandine , Philippe Mickael , Bertrand Yves , Plantaz Dominique , Bleyzac Nathalie
Published: October 2013

Optimal modalities for immunosuppressive therapy (IST) for severe aplastic anemia (SAA) have to be determined, and especially cyclosporine (CyA) dosing to promote regulatory T cells (Treg) which are lacking and which account for physiopathological mechanisms. We are reporting on three cases of pediatric patients suffering from SAA, initially without hematological response between 4 and 7 months after IST, and who have responded 2 months after the decrease in CyA target trough blood levels to 100 ng/mL, and one case which has early responded by applying low trough blood levels from the beginning. As it has been demonstrated that Treg increase in IST responders and that Treg are stimulated only by low CyA concentrations, these case series suggest that lower CyA doses than actually recommended could be more efficient to enhance the proportion of responders. This report highlights a new field of perspectives for the treatment for SAA.
Postnatal development of temporal integration, spike timing and spike threshold regulation by a dendrotoxin‐sensitive K+ current in rat CA1 hippocampal cells
Authors: Giglio Anna M. , Storm Johan F.
Published: October 2013

Spike timing and network synchronization are important for plasticity, development and maturation of brain circuits. Spike delays and timing can be strongly modulated by a low‐threshold, slowly inactivating, voltage‐gated potassium current called D‐current (ID). ID can delay the onset of spiking, cause temporal integration of multiple inputs, and regulate spike threshold and network synchrony. Recent data indicate that ID can also undergo activity‐dependent, homeostatic regulation. Therefore, we have studied the postnatal development of ID‐dependent mechanisms in CA1 pyramidal cells in hippocampal slices from young rats (P7–27), using somatic whole‐cell recordings. At P21–27, these neurons showed long spike delays and pronounced temporal integration in response to a series of brief depolarizing current pulses or a single long pulse, whereas younger cells (P7–20) showed shorter discharge delays and weak temporal integration, although the spike threshold became increasingly negative with maturation. Application of α‐dendrotoxin (α‐DTX), which blocks ID, reduced the spiking latency and temporal integration most strongly in mature cells, while shifting the spike threshold most strongly in a depolarizing direction in these cells. Voltage‐clamp analysis revealed an α‐DTX‐sensitive outward current (ID) that increased in amplitude during development. In contrast to P21–23, ID in the youngest group (P7–9) showed smaller peri‐threshold amplitude. This may explain why long discharge delays and robust temporal integration only appear later, 3 weeks postnatally. We conclude that ID properties and ID‐dependent functions develop postnatally in rat CA1 pyramidal cells, and ID may modulate network activity and plasticity through its effects on synaptic integration, spike threshold, timing and synchrony.
Responsible scientists and a citizens' panel: new storylines for creative engagement between science and the public
Authors: Robinson Philip A , Macnaghten Phil , Banks Sarah , Bickersteth Janie , Kennedy Angela , Richardson Yvonne , Shaw Sue , Sylvestre Ingrid
Published: October 2013

Uncertainties over emerging technologies and their potential effect on society and the environment often lead to controversy between scientists, policymakers and the public. Opening up the debates and involving citizens and social scientists early in the process of developing new technology is one way of responding to this issue of governance. By doing so, the hope is that the ethical implications and acceptability of new science can be more carefully considered and framed in a responsible and democratised context. To explore an example of aspiration in practice, a series of interdisciplinary public engagement events was organised atDurham University under the title New Storylines for Living with Environmental Change: Citizens' Perspectives. In this commentary we report on one of these events, a one‐day workshop entitled Responsible Science and Public Engagement, where a citizens' panel aimed to explore ways of conducting deliberative engagement with scientists using the creative arts and a scientific dilemmas café format.
Household norms and their role in reducing household electricity consumption
Authors: Kleinschafer Jodie , Morrison Mark
Published: October 2013

Researchers have only recently begun to investigate the role of the norms of the household or family group in energy‐efficiency decisions. These researchers have demonstrated that these norms can influence the behaviour and attitudes of children within the household. We contribute to their findings by providing a characterization of the use of household norms in household decisions about electricity efficiency. For our qualitative research, we conducted focus groups with three different household types: (1) share houses/young couples with no children; (2) households with children; and (3) empty nest/elderly households in three regional centres in New South Wales, Australia (total of 76 respondents in nine focus groups). Specifically, we found that household norms were evident in the decision‐making process through rules and expectations about behaviour and the use of sanctions to enforce or shaped that behaviour. We identified several drivers of household norms including a household member taking the role of ‘efficiency champion’ and the occurrence of critical incidents in the household. In addition, we found that household members try to establish household norms to socialize household members with the goal of the intergenerational transmission of desirable behaviours. Based on these observations, we conclude that household members employ norms to regulate and reduce their electricity consumption, and as a mechanism for consumer socialization. As such, our findings are important for marketers and policy makers tasked with regulating household consumption.
Cytokine expression in phytohaemagglutinin‐induced skin inflammation in a galliform bird
Authors: Vinkler Michal , Svobodová Jana , Gabrielová Barbora , Bainová Hana , Bryjová Anna
Published: October 2013

Researchers interested in ecological immunology face substantial methodological problems: 1) most immunological approaches are difficult to perform in free‐living animals, 2) in some of the applicable methods the immunological background of the test remains unclear. The latter is also true for the phytohaemagglutinin (PHA) skin‐swelling test, a trait of cell‐mediated immunity commonly measured in ecology. A lack of direct evidence documenting the immunological processes in the tissue limits our understanding of the mechanism triggering the response to PHA. Understanding of this mechanism is, nonetheless, crucial for us to uncover the nature of ecological costs and benefits of investments into the response. As knowledge of cytokine signalling in the tissue may clarify the response mechanism, in our study we investigated the association between the PHA‐induced skin‐swelling and tissue cytokine expression in males of grey partridge Perdix perdix. In PHA‐challenged birds we assessed expression of nine cytokines (IL‐1β, IL‐2, IL‐4, IL‐6, IL‐10, IL‐12, IL‐17, TGF‐β, IFN‐γ) in wing‐web skin during an early stage of the immune response. We examined the relationship between the magnitude of tissue swelling and cytokine expression. Contrary to some earlier expectations we did not find any differential expression of T‐cell growth factor, IL‐2, in the tissue. Hence, T‐cell proliferation at the time of the swelling measurement is unlikely. We detected differential expression in Th17 pro‐inflammatory (IL‐1β, IL‐6) and anti‐inflammatory (TGF‐β) cytokines. The PHA‐induced swelling response was only weakly linked to the expression of TGF‐β. We also found relationships between the PHA‐induced swelling response and phenotypic traits of the birds; the PHA swelling was positively associated with the extent of melanin‐based breast ornamentation and negatively related to body size. Our results might suggest that variation in swelling is influenced by total numbers of responding cells rather than by differences in signalling. Moreover, we revealed significant correlations in expression of IL‐1β, IL‐6 and TGF‐β. These findings are the first to show on the molecular level that the PHA skin‐swelling test actually measures inflammation process which is part of innate immune defence and not the adaptive immune response (as assumed if the test was the reflection of T‐cell proliferation).
Structure meets function: actin filaments and myosin motors in the axon
Authors: Arnold Don B. , Gallo Gianluca
Published: October 2013

This review focuses on recent advances in the understanding of the organization and roles of actin filaments, and associated myosin motor proteins, in regulating the structure and function of the axon shaft. ‘Patches’ of actin filaments have emerged as a major type of actin filament organization in axons. In the distal axon, patches function as precursors to the formation of filopodia and branches. At the axon initial segment, patches locally capture membranous organelles and contribute to polarized trafficking. The trapping function of patches at the initial segment can be ascribed to interactions with myosin motors, and likely also applies to patches in the more distal axon. Finally, submembranous rings of actin filaments were recently described in axons, which form an actin‐spectrin cytoskeleton, likely contributing to the maintenance of axon integrity. Continued investigation into the roles of axonal actin filaments and myosins will shed light on fundamental aspects of the development, adult function and the repair of axons in the nervous system.

image

This review focuses on recent advances in the understanding of the organization and roles of actin filaments, and associated myosin motor proteins, in regulating the structure and function of the axon shaft. Actin filament patches at the initial segment capture vesicles incorrectly being transported anterogradely into the axon (see schematic). When the vesicle is released from the patch, it undergoes retrograde transport back to the soma. Along the distal axon, actin patches serve as precursors to the emergence of filopodia, the first step in axon branching.
Magnetic resonance fetal right lung volumetry and its efficacy in predicting postnatal short‐term outcomes of congenital left‐sided diaphragmatic hernia
Authors: Hidaka Nobuhiro , Ishii Keisuke , Furutake Yoko , Yamamoto Ryo , Sasahara Jun , Mitsuda Nobuaki
Published: October 2013

Aim

We aimed to investigate whether the ratio of magnetic resonance imaging (MRI)‐measured right lung volume (RLV) to ultrasonography‐estimated bodyweight (RLV/BW) and observed‐to‐expected (o/e) RLV are of diagnostic value in predicting postnatal outcomes of left congenital diaphragmatic hernia (CDH).

Material and Methods

We included 32 CDH patients and 34 control subjects. Manually outlined fetal right lung areas on MRI were multiplied by the slice thickness and added to determine the entire volume. The association between RLV and RLV/BW with gestational age in the controls was examined using regression analysis. RLV/BW and o/e RLV were compared between surviving and non‐surviving neonates with CDH.

Results

The expected fetal RLV was derived using the formula RLV (mm3) = 1.717 × (gestational weeks)2.82. In the controls, RLV/BW was nearly constant during the third trimester. The 27 survivors with CDH had a median RLV/BW of 10.7 and a median o/e RLV of 60.0, whereas the five non‐surviving neonates had a median RLV/BW of 4.3 and a median o/e RLV of 22.6; the differences were statistically significant.

Conclusion

Assessment of fetal lungs by MRI volumetry is reliable for clinical use. RLV/BW and o/e RLV are potential predictors of postnatal outcomes of left CDH.
Paraneoplastic cerebellar degeneration caused by ovarian clear‐cell carcinoma
Authors: Negishi Y. , Sakai K. , Noguchi Y. , Iwasaki N. , Kawai N.
Published: October 2013

Paraneoplastic cerebellar degeneration is a paraneoplastic neurological syndrome caused by the remote effect of certain systemic cancers and is characterized by subacute cerebellar symptoms. A 62‐year‐old woman suffering from unidentified cerebellar symptoms was admitted to our hospital. Paraneoplastic cerebellar degeneration was suspected and ovarian cancer was detected after the systemic examination for malignancy. The symptoms of vertigo and dysarthria were improved a little after surgical operation and treatments of γ‐globulin, steroid pulse and tacrolimus hydrate. The cerebellar symptoms of paraneoplastic cerebellar degeneration are often evident prior to detection of malignancy. It is important to perform systemic examination for malignancy in case of unidentified cerebellar symptoms.
Prizes, Publicity and Patents: Non‐Monetary Awards as a Mechanism to Encourage Innovation
Authors: Moser Petra , Nicholas Tom
Published: October 2013

This paper exploits the selection of prize‐winning technologies among exhibitors at the Crystal Palace Exhibition in 1851 to examine whether—and how—ex post prizes that are awarded to high‐quality innovations may encourage future innovation. U.S. patent data indicate a 40 per cent increase after 1851 in patenting for prize‐winners compared with other exhibits. Results are robust to controlling for technology‐specific pre‐trends and for the quality of patents. A comparison of changes in patenting for prize‐winners with changes for technologies that were described on the front page of the Scientific American suggests that publicity for promising research fields may be an important mechanism by which ex post prizes encourage future innovation.
Incidence and Growth of Patent Thickets: The Impact of Technological Opportunities and Complexity
Authors: von Graevenitz Georg , Wagner Stefan , Harhoff Dietmar
Published: October 2013

We analyze incidence and evolution of patent thickets. The paper provides a modeling framework showing how competition for patent portfolios, complementarity of patented technologies and hold‐up affect patenting. Predictions are that technological opportunity reduces patenting in complex technologies, while increasing patenting in discrete technologies. Competition has the opposite effects. The predictions are tested using European patent data in a panel with 2,074 patenting firms in thirty technology areas over fifteen years. A new measure of technological complexity is applied.GMMestimation results confirm the predictions of our preferred model. Patent thickets are found in nine out of thirty technology areas.
Chronic melatonin treatment rescues electrophysiological and neuromorphological deficits in a mouse model ofDown syndrome
Authors: Corrales Andrea , Vidal Rebeca , García Susana , Vidal Verónica , Martínez Paula , García Eva , Flórez Jesús , Sanchez‐Barceló Emilio J. , Martínez‐Cué Carmen , Rueda Noemí
Published: October 2013

The Ts65Dn mouse (TS), the most commonly used model of Down syndrome (DS), exhibits several key phenotypic characteristics of this condition. In particular, these animals present hypocellularity in different areas of theirCNSdue to impaired neurogenesis and have alterations in synaptic plasticity that compromise their cognitive performance. In addition, increases in oxidative stress during adulthood contribute to the age‐related progression of cognitive and neuronal deterioration. We have previously demonstrated that chronic melatonin treatment improves learning and memory and reduces cholinergic neurodegeneration inTSmice. However, the molecular and physiological mechanisms that mediate these beneficial cognitive effects are not yet fully understood. In this study, we analyzed the effects of chronic melatonin treatment on different mechanisms that have been proposed to underlie the cognitive impairments observed inTSmice: reduced neurogenesis, altered synaptic plasticity, enhanced synaptic inhibition and oxidative damage. Chronic melatonin treatment rescued both impaired adult neurogenesis and the decreased density of hippocampal granule cells in trisomic mice. In addition, melatonin administration reduced synaptic inhibition inTSmice by increasing the density and/or activity of glutamatergic synapses in the hippocampus. These effects were accompanied by a full recovery of hippocampalLTPin trisomic animals. Finally, melatonin treatment decreased the levels of lipid peroxidation in the hippocampus ofTSmice. These results indicate that the cognitive‐enhancing effects of melatonin in adultTSmice could be mediated by the normalization of their electrophysiological and neuromorphological abnormalities and suggest that melatonin represents an effective treatment in retarding the progression ofDSneuropathology.
MULTIVARIATE LIMIT THEOREMS IN THE CONTEXT OF LONG‐RANGE DEPENDENCE
Authors: Bai Shuyang , Taqqu Murad S.
Published: October 2013

We study the limit law of a vector made up of normalized sums of functions of long‐range dependent stationary Gaussian series. Depending on the memory parameter of the Gaussian series and on the Hermite ranks of the functions, the resulting limit law may be (a) a multi‐variate Gaussian process involving dependent Brownian motion marginals, (b) a multi‐variate process involving dependent Hermite processes as marginals or (c) a combination. We treat cases (a) and (b) in general and case (c) when the Hermite components involve ranks 1 and 2. We include a conjecture about case (c) when the Hermite ranks are arbitrary, although the conjecture can be resolved in some special cases.
Comparative assessment of genetic diversity between wild and cultivated barley using gSSR and EST‐SSR markers
Authors: Nandha Prabhjot S. , Singh Jaswinder
Published: October 2013

Barley is an economically important cereal crop especially for feed and malt production, but its value as food is increasing due to various health benefits. Wild barley is the progenitor of modern day barley cultivars possessing a rich source of genetic variation for various biotic and abiotic stresses. Species‐specific molecular markers have great potential for efficient introgression of these important traits from wild to cultivated barley. In the present study, 140 microsatellite markers were screened to assess the genetic variation and species‐specific markers between wild and cultivated germplasm. Of these 140, a polymorphic set of 48 genomic (gSSR) and 16 EST‐SSRs amplified a total of 685 alleles. Cluster analysis discriminated all 47 accessions and classified wild and cultivated genotypes into two distinct groups, according to their geographic origin. Our analysis indicated that gSSRs were more informative than EST‐based SSRs. Results from PCoA analysis for species‐specific alleles clearly suggest that wild barley genotypes contain a higher number of unique alleles.
Garbage‐can Policy‐making Meets Neo‐liberal Ideology: Twenty Five Years of Redundant Reform of theEnglishNationalHealthService
Authors: Paton Calum
Published: October 2013

The garbage‐can theory of decision‐making (Cohenet al. 1972), has been adapted into a perspective on policy‐making, with adaptations of the approach placing notable emphasis upon the health sector (Kingdon 2006;Paton 2006). This article creates an adapted ‘garbage‐can’ framework to help explain each stage of the reform of theEnglishNationalHealthService (NHS) over the last 25 years.

The emergence of the key idea and resultant policy at each stage of reform of theEnglishNHShas been arational and indeed sometimes irrational. Policy has reflected advocacy by policy‐salesmen (Kingdon 2002), proffering ‘solutions’ to ill‐defined problems and answers to unasked questions, and politicians' short‐termist responses at each decision‐point.

Yet the garbage‐can alone is not enough: if arationality rules in policy‐making day to day, this does not mean that there is not an overall ideological context, trend or bias in reform. The article also posits that ‘market reform’ has derived from the ideological hegemony of a naive anti‐statism (hostility to a misleadingly defined and often mythological ‘centralist state’) in public services and enthusiasm for market competition rather than any evidence‐based application of pro‐market ideas to health policy.

A question arises: how are these two approaches (short‐term arationality and longer‐term ideological bias) combined in explanation of how policy over time is biased in a particular direction while seemingly arbitrary and directionless at each messy decision‐point. The article attempts to combine the insights of a garbage‐can approach with wider explanations of ideological hegemony.
Direct isolation of flavonoids from plants using ultra‐small anatase TiO2 nanoparticles
Authors: Kurepa Jasmina , Nakabayashi Ryo , Paunesku Tatjana , Suzuki Makoto , Saito Kazuki , Woloschak Gayle E. , Smalle Jan A.
Published: October 2013

Surface functionalization of nanoparticles has become an important tool for in vivo delivery of bioactive agents to their target sites. Here we describe the reverse strategy, nanoharvesting, in which nanoparticles are used as a tool to isolate bioactive compounds from living cells. Anatase TiO2 nanoparticles smaller than 20 nm form strong bonds with molecules bearing enediol and especially catechol groups. We show that these nanoparticles enter plant cells, conjugate enediol and catechol group‐rich flavonoids in situ, and exit plant cells as flavonoid‐nanoparticle conjugates. The source plant tissues remain viable after treatment. As predicted by the surface chemistry of anatase TiO2 nanoparticles, quercetin‐based flavonoids were enriched amongst the nanoharvested flavonoid species. Nanoharvesting eliminates the use of organic solvents, allows spectral identification of the isolated compounds, and opens new avenues for use of nanomaterials for coupled isolation and testing of bioactive properties of plant‐synthesized compounds.
Spatio‐temporal analysis of cellulose synthesis during cell plate formation in Arabidopsis
Authors: Miart Fabien , Desprez Thierry , Biot Eric , Morin Halima , Belcram Katia , Höfte Herman , Gonneau Martine , Vernhettes Samantha
Published: October 2013

During cytokinesis a new crosswall is rapidly laid down. This process involves the formation at the cell equator of a tubulo‐vesicular membrane network (TVN). This TVN evolves into a tubular network (TN) and a planar fenestrated sheet, which extends at its periphery before fusing to the mother cell wall. The role of cell wall polymers in cell plate assembly is poorly understood. We used specific stains and GFP‐labelled cellulose synthases (CESAs) to show that cellulose, as well as three distinct CESAs, accumulated in the cell plate already at the TVN stage. This early presence suggests that cellulose is extruded into the tubular membrane structures of the TVN. Co‐localisation studies using GFP–CESAs suggest the delivery of cellulose synthase complexes (CSCs) to the cell plate via phragmoplast‐associated vesicles. In the more mature TN part of the cell plate, we observed delivery of GFP–CESA from doughnut‐shaped organelles, presumably Golgi bodies. During the conversion of the TN into a planar fenestrated sheet, the GFP–CESA density diminished, whereas GFP–CESA levels remained high in the TVN zone at the periphery of the expanding cell plate. We observed retrieval of GFP–CESA in clathrin‐containing structures from the central zone of the cell plate and from the plasma membrane of the mother cell, which may contribute to the recycling of CESAs to the peripheral growth zone of the cell plate. These observations, together with mutant phenotypes of cellulose‐deficient mutants and pharmacological experiments, suggest a key role for cellulose synthesis already at early stages of cell plate assembly.
A BrachyPhantom for verification of dose calculation of HDR brachytherapy planning system
Authors: Austerlitz C. , Campos C. A. T.
Published: October 2013

Purpose:

To develop a calibration phantom for192Ir high dose rate (HDR) brachytherapy units that renders possible the direct measurement of absorbed dose to water and verification of treatment planning system.

Methods:

A phantom, herein designated BrachyPhantom, consists of a Solid Water™ 8‐cm high cylinder with a diameter of 14 cm cavity in its axis that allows the positioning of an A1SL ionization chamber with its reference measuring point at the midheight of the cylinderˈs axis. Inside the BrachyPhantom, at a 3‐cm radial distance from the chamberˈs reference measuring point, there is a circular channel connected to a cylindrical‐guide cavity that allows the insertion of a 6‐French flexible plastic catheter from the BrachyPhantom surface. The PENELOPE Monte Carlo code was used to calculate a factor,, to correct the reading of the ionization chamber to a full scatter condition in liquid water. The verification of dose calculation of a HDR brachytherapy treatment planning system was performed by inserting a catheter with a dummy source in the phantom channel and scanning it with a CT. The CT scan was then transferred to the HDR computer program in which a multiple treatment plan was programmed to deliver a total dose of 150 cGy to the ionization chamber. The instrument reading was then converted to absorbed dose to water using the Ngas formalism and the factor. Likewise, the absorbed dose to water was calculated using the source strength, Sk, values provided by 15 institutions visited in this work.

Results:

A value of 1.020 (0.09%,k = 2) was found for . The expanded uncertainty in the absorbed dose assessed with the BrachyPhantom was found to be 2.12% (k = 1). To an associated Sk of 27.8 cGy m2 h−1, the total irradiation time to deliver 150 cGy to the ionization chamber point of reference was 161.0 s. The deviation between the absorbed doses to water assessed with the BrachyPhantom and those calculated by the treatment plans and using the Sk values did not exceed ±3% and ±1.6%, respectively.

Conclusions:

The BrachyPhantom may be conveniently used for quality assurance and/or verification of HDR planning system witha priori threshold level to spot problems of 2% and ±3%, respectively, and in the long run save time for the medical physicist.
Modeling of ultrasonic backscatter using ultrasonic radiative transfer theory
Authors: Ghoshal Goutam , Turner Joseph A.
Published: October 2013

The scattering of elastic waves in polycrystalline media is primarily due to the elastic inhomogeneities present between grains. This scattering may be used to extract the microstructural parameters of the material such as grain size and grain texture. In particular, ultrasonic backscatter measurements have been especially useful for extracting microstructural information. From the theoretical perspective, derivations related to ultrasonic radiative transfer equations (URTE) govern the propagation of diffuse intensities and include all multiple scattering effects. In this presentation, a rigorous connection between the URTE theory and the backscatter experiments is discussed. The general URTE formulation is first reduced to the singly scattered problem. The backscattered ultrasonic flux is shown to be the main quantity of interest. The flux is obtained in terms of the relevant scattering parameters. Specific solutions are obtained for a specimen excited by a normally incident longitudinal wave. The backscatter model for a normally incidental longitudinal wave and its mode converted shear wave are discussed. The theoretical results are compared with numerical simulations based on Voronoi polycrystal finite-element calculations. Results are also compared with previous backscattering theories. Relevant applications for materials of common interest are also discussed. [Work supported by DOE.]
Bragg backscatter and band structure in a sinusoidal waveguide model
Authors: Valente Dan , Swanson David C.
Published: October 2013

The unique characteristics of wave propagation through periodic acoustic structures have been well known for many years. These structures allow only certain bands of frequencies to propagate through the system, resulting in a distinct filter response. The purpose of this work is to investigate the properties of a periodic waveguide whose walls vary sinusoidally along its length. The waveguide is modeled using a transmission line/transfer matrix approach to obtain the power reflection and transmission coefficients at the waveguide input. Typically in the literature, waveguides with distinct periodic scatterers or abrupt area changes have been examined, and a distinct band structure is evident. It is shown that for small amplitude wall variations of the sinusoidal waveguide, the system denies the transmission of only one frequency. This frequency fits the condition for Bragg backscatter, a phenomenon that is analogous to what is observed in the acousto-optic (AO) effect. As the amplitude of the wall variations increase, however, a band structure similar to what is expected for periodic systems begins to arise. [Work supported by FRA.]
Further results on acoustic scattering from the edge of a wedge
Authors: Hughes Ronald , Niemiec Jan M. , Stoyanov Yuri , Überall Herbert
Published: October 2013

Acoustic monostatic and bistatic scattering from the edge of a solid wedge immersed in water is analyzed further, always assuming a line source parallel to the edge of a wedge. Our previous work on the subject is extended by emphasizing the dependence of the scattering amplitude on the wedge material, which may be uniform or layered, and which can be characterized by surface impedance. Impedance values are obtained for multiple layers by the method of Brekhovskihk. Our numerical analysis is based upon Macdonald functions [A. Erdelyi, Higher Transcendental Functions (McGraw–Hill, New York, 1953)] via an integral representation that we were able to render convergent. The scattering amplitude is integral bilinear in the Macdonald functions and dependent upon the wedge impedance, and has been evaluated numerically. [Work supported by NAVSEA.]
Synthetic vowel categorization by hearing-impaired listeners
Authors: Molis Michelle R. , Leek Marjorie R.
Published: October 2013

Vowel identification performance can be predicted reasonably well for normal-hearing (NH) listeners based on principal components derived from excitation patterns [M. R. Molis, J. Acoust. Soc. Am. 111, 2433–2434 (2002)]. In this study, vowel categorization was measured in listeners with mild-to-moderate hearing loss. Stimuli were 54 synthesized vowels that varied orthogonally in F2 (1081–2120 Hz) and F3 (1268–2783 Hz) frequency in equal 0.8-bark steps. Fundamental frequency contour, F1 (455 Hz), F4 (3250 Hz), F5 (3700 Hz), and duration (225 ms) were held constant. Hearing-impaired (HI) listeners categorized the stimuli as the vowels /I/, /U/, or /ɝ/. Estimates of frequency resolution were also obtained, and excitation patterns were constructed for each listener. Categorization performance was more variable for HI listeners relative to NH listeners, both within and between listeners. Many subjects appeared to rely solely on F2 frequency and had particular difficulty with the /U/ vs /ɝ/ distinction. Excitation patterns suggested a rather imprecise internal spectral representation of the stimuli. HI response patterns may reflect decreased audibility, spectral smearing of formant structure due to poor frequency resolution, or both. Models of vowel perception based on the impaired excitation patterns will be compared with formant-based models. [Work supported by NIH (DC00626).]
Dichotic presentation to overcome the effect of increased spectral masking and frequency dependent hearing threshold shifts in persons with bilateral sensorineural impairment
Authors: Cheeran Alice N. , Pandey Prem C.
Published: October 2013

A binaural dichotic presentation scheme for reducing the effect of increased spectral masking in persons with bilateral sensorineural loss, using spectral splitting with complementary comb filters based on auditory critical bands, has been earlier reported [Cheeran et al., J. Acoust. Soc. Am. 110, 2705 (2001)]. The 256-coefficient linear phase FIR filters designed using frequency sampling technique had transition crossovers adjusted within −6 to −4 dB for perceptual balance, and had 78–117 Hz transition, 1 dB passband ripple, and 30 dB stopband attenuation. We evaluated the scheme by conducting listening tests on 5 normal hearing subjects with simulated loss, using a closed set identification of 12 vowel-consonant-vowel syllables. Based on significant improvement, further tests were conducted on 5 hearing-impaired persons with moderate bilateral sensorineural loss. Significant improvement in response time, recognition scores, and transmission of consonantal features, particularly place and duration, was obtained, indicating reduction in the effect of spectral masking. In order to partly compensate for frequency dependent hearing threshold shifts, a pair of filters with frequency response adjusted within a 6 dB range, based on the audiogram for the corresponding ear, was cascaded with the comb filters. These filters resulted in additional improvement, particularly for persons with relatively uniform loss.
Cross-linguistic preference and the phonetics of geminates: Place of articulation and duration of phonologically short and long consonants in Guinaang Bontok
Authors: Aoyama Katsura
Published: October 2013

It is reported that there is a preference for the place-of-articulation in geminates among world languages; alveolar, labial, velar geminate consonants always appear in that order with respect to one another (G. Thurgood, Papers in Honor of Frederick H. Brengelman, 1993, pp. 129–137). This study investigated whether the phonetic contrasts in duration are larger in cross-linguistically favored place-of-articulation (e.g., alveolar) than in the less favored place-of-articulation (e.g., velar). The data is from a language called Guinaang Bontok. Four speakers of Guinaang Bontok produced thirty-five words that have either a singleton or a geminate of /p t k m n ŋ/. Eighteen words included a singleton and the other seventeen words included a geminate. The participants produced the target word in isolation first, and then repeated it in a frame sentence twice. The recordings were digitized at 22.05 Hz, and the durations of the consonants were measured. A total of 420 tokens (35 words ×3 repetitions ×4 participants) were analyzed. The results partially supported the hypothesis; the durational contrasts were indeed larger in alveolar consonants (/t n/) than in labial consonants (/p m/) and velar consonants (/ŋ/). However, contrasts in velar stop (/k/) were as large as in the alveolar stop (/t/).
Word-final nasals in Romanian
Authors: Tucker Benjamin
Published: October 2013

In this study Romanian word-final nasals, e.g., /basm/ ‘‘fairytale,’’ are examined acoustically. Acoustic descriptions of Romanian are few, but early research indicated that word-final nasals are devoiced or partially devoiced. In this study an acoustic analysis of cross-linguistically unusual voiceless nasals, as well as information about a language which has not been phonetically well-documented is provided. In the current work the word-final /sm, mn, Vm, Vn/ are examined. The words were placed in various phonological environments (e.g., utterance final, before vowel-initial following word, etc.). Eight Romanian speakers were recorded. A judgment of voicing was made from the spectrogram. The duration of the gap between the /s/ and /m/, the total duration of voiced nasals and the duration of the preceding vowel were measured. The data was also analyzed for the presence of a release noise at the end of the nasal, which indicates that there is an oral closure during the nasal, and hence that the nasal is devoiced rather than deleted. Preliminary data shows that the average duration for /mn/ (0.148 ms) is longer than the duration of the /n/ or /m/ (0.105 ms) further indicating that deletion is not occurring. The preliminary data also shows that 93% of nasals in the /sm/ sequences are devoiced.
Discriminability and identification of English vowels by native Japanese speakers in different consonantal contexts
Authors: Nozawa Takeshi , Frieda Elaina M. , Wayland Ratree
Published: October 2013

The purpose of the present experiment was to examine the effects of consonantal context on discrimination and identification of English vowels by native Japanese speakers learning English in Japan. A number of studies have assessed the effects of consonantal contexts on the perception of nonnative vowels. For instance, Strange et al. (1996, 2001) found that perceptual assimilation of nonnative vowels is affected by consonantal contexts, and Morrison (2002) has shown that Japanese speakers use durational cues to perceive English /i/–/I/. The present study revealed that consonantal context affects discriminability and identification of each English vowel differently. Of all the six vowel contrasts tested, /i/–/I/ was the most likely to be affected by voicing status of the surrounding consonants with it being easier to discriminate in voiceless consonantal contexts. Moreover, /I/ is more likely to be equated with the Japanese short vowel /i/ in a voiceless consonantal context which is in keeping with Morrison (2002). /æ/–/ɑ/, on the other hand, is the most strongly affected by the place of articulation of the preceding consonants. [Work supported by Grant-in-Aid for Scientific Research (C)(1)(1410635).]
Allophonic variation of Japanese /z/
Authors: Matsugu Yuka , Vance Timothy J.
Published: October 2013

According to impressionistic descriptions, the Japanese phoneme /z/ is pronounced sometimes as a fricative [z] and sometimes as an affricate [dz]. There is no consensus about how the two allophones are distributed, but one claim is that they are in complementary distribution: [dz] word initially or after a nasal and [z] intervocalically. Native speakers of ‘‘standard’’ Japanese pronounced words containing /z/ in a carrier sentence. Using spectrograms and waveforms, two (necessarily approximate) measurements were taken for each token of /z/: total duration and closure duration. The results did not show a categorical affricate/fricative distinction. Some word-initial and post-nasal tokens had no measurable closure, while many intervocalic tokens had clear closure. Nonetheless, the average closure duration was significantly longer for word-initial and post-nasal tokens of /z/ than for intervocalic tokens, and a much higher proportion of intervocalic tokens had zero closure. These results partially support the distributional claim above but make it clear that the allophonic variation involves two statistically different ranges of realizations rather than a categorical distinction between two discrete alternatives.
Scattering and attenuation from near-surface bubbles
Authors: Dahl Peter H.
Published: October 2013

Scattering from bubbles in the vicinity of the air–sea interface can often be the dominant source of apparent sea surface backscatter, particularly for lower grazing angles and for frequencies of O(10) kHz and above. Such scattering, and by inference, the near-surface bubble concentration, is observed in field data to be highly correlated with a nonlinear function of wind speed, such as a power or exponential law. A hysteresis effect is also observed, wherein for a given wind speed there is a tendency for scattering level to be higher if prior winds had been falling. The situation changes for acquisition geometries far removed from monostatic or bistatic backscattering; for example, in the case of bistatic forward scattering, the scattering level from bubbles rarely reaches the strength of that from the air–sea interface. Here, though, a bubble-mediated attenuation can be observed in field data, which is also wind-speed dependent with hysteresis. However, linking together field measurements of scattering and attenuation associated with near-surface bubbles has long been a vexing problem. This topic is discussed using examples from various field experiments, the most recent of which is ASIAEX East China Sea (2001), and from well-controlled laboratory experiments. [Research supported by ONR.]
Analysis of audiometric database shows evidence of employee fraud
Authors: Erdreich John
Published: October 2013

Following a lengthy strike, several hundred delivery drivers filed workers compensation claims for occupational hearing loss. We were asked to evaluate the noise exposure of the drivers during their in-plant tasks. In-plant exposures were not predictive of any hearing loss. A comparison of audiometric data for the claimants revealed consistent hearing loss independent of duration of employment or age. These discrepancies between observations and common understanding of dose–response relationships between noise exposure and hearing loss led to further investigation, ultimately resulting in the dismissal of all claims against the employer who then filed an action against the claimant’s attorneys and physician under the Racketeering in Corrupt Organizations Act (RICO). The details of the legal complaint, which reads like a detective novel, can be found at the United States District Court for the Southern District of New York [93 Civ. 7222 (LAP)].
Fish schooling behavior inferred from differences between backscatter levels in Doppler sonar beams
Authors: Zedel Len
Published: October 2013

The general availability of Doppler profilers on survey ships provides a convenient source of acoustic backscatter data. Aside from calibration issues, caution must be exercised when analyzing this data because each of the diverging beams has a different interaction angle with the scatterers. In particular, for targets with directional scattering characteristics a different backscatter strength will be seen in each beam. The availability of data from multiple beam directions can however provide information on scatterer orientation when groups of such scatterers undertake coherent motion. This effect is demonstrated in observations of Norwegian spring spawning herring (Clupea harengus). In data collected while these fish are actively migrating with mean swimming speeds of 20 cms−1, a difference of 5 dB is seen in volume backscatter strength depending on the direction of fish movement with respect to the acoustic beams. In contrast, in data collected when these fish schools have less well defined movements with a mean swimming speed of less than 10 cms−1, a difference of less than 1 dB is seen.
Long-range acoustic imaging of the Continental Shelf Environment reveals massive fish schools: 2003 Main Acoustic Clutter Experiment
Authors: Makris Nicholas C. , Ratilal Purnima , Lai Yisan , Lee Sunwoong , Symonds Deanelle T. , Ruhlmann Lilimar A. , Nero Redwood W. , Preston John R. , Scheer Edward K. , Sundvik Michael T.
Published: October 2013

Results from the three-ship, April–May 2003 Main Acoustics Experiment of the ONR Acoustics Clutter Program are presented. A long-range bistatic sonar system was used to image extensive clutter over wide areas of the New Jersey Continental Shelf in the low- to mid-frequency range in near real-time. A downward-directed high-frequency fish-finding sonar was also simultaneously operated from one of the ships to determine whether fish schools occur in the location of the clutter events. Tracks of the long-range sonar were repeated over days throughout the experiment. Most of the clutter features were observed to evolve both in time and in space moving throughout the survey area and therefore do not consistently correlate with static geologic features. The clutter features were observed to cluster, disperse, and gradually disappear and then re-emerge in the general vicinity at later times. The long-range active sonar data show that the primary source of clutter corresponds to objects moving in the waveguide. This was made certain by our ability to accurately register a number of fixed point targets deployed as controls throughout the experiment. The preliminary finding of this experiment is that the dominant source of clutter in this Continental Shelf environment is marine life, particularly fish schools.
Radiation force produced by time reversal acoustic focusing system
Authors: Sarvazyan Armen , Sutin Alexander
Published: October 2013

An ultrasonic induced radiation force is an efficient tool for remote probing of internal anatomical structures and evaluating tissue viscoelastic properties, which are closely related to tissue functional state and abnormalities. Time Reversal Acoustic Focusing System (TRA FS) can provide efficient ultrasound focusing in highly inhomogeneous media. Furthermore, numerous reflections from boundaries, which distort focusing in conventional ultrasound focusing systems and are viewed as a significant technical hurdle, lead to an improvement of the focusing ability of the TRA system. In this work the TRA FS field structure and radiation force in a transcranial phantom were investigated. A simple TRA FS comprising a plane piezoceramic transducer attached to an external resonator such as an aluminum block was acoustically coupled to the tested transcranial phantom. A custom-designed compact electronic unit for TRA FS provided receiving, digitizing, storing, time reversing and transmitting of acoustic signals in a wide frequency range from 0.01 to 10 MHz. The radiation force produced by ultrasonic pulses was investigated as a function of the transmitted ultrasound temporal parameters. The simplest TRA FS provided focusing of 500 kHz ultrasound pulses and the generation of a radiation force with an efficacy hardly achievable using conventional sophisticated phased array transmitters. [Work supported by NIH.]
Error in the measurement of acoustic impedance by the two-microphone method
Authors: Post John T.
Published: October 2013

Methods for measuring acoustic impedance have traditionally been slow, physically bulky, and difficult to accurately implement. A technique known as the two-microphone method is presented, which overcomes these previous limitations. The performace of this method is evaluated by an error study which shows the relationship of the measurement error and the measured impedance load and microphone spacing. The two-microphone method is then compared with another method, the reaction-on-the-source method, and the advantages and disadvantages of both are discussed. The two-microphone method is shown to be robust with loads that are dominantly inertial in the low-frequency limit.
Comparison between musical acoustics parameters of an upright and a grand piano
Authors: Wogram Klaus , Mori Taro
Published: October 2013

‘‘Why does a grand piano sound so much better than an upright piano?’’ This question is frequently discussed. Is it the sound itself, or the inharmonicity, or is it the way of playing the different instruments, or the sound pattern? All these questions have been investigated in the former laboratory of musical acoustics of the PTB by Taro Mori with very interesting results. Results of measurements and subjective hearing tests will be presented, and the method itself will be explained. One of the most interesting findings is that it is nearly impossible to distinguish between an upright and a grand piano in hearing tests by listening only to single tones, sequences of tones or chords. Better results are found by performing complete musical pieces on the instruments under test.
Overview of the University of Wyoming’s hexapod program
Authors: McInroy John
Published: October 2013

For the past eight years, the University of Wyoming (UW) has been developing parallel kinematics machines to perform fault tolerant precision pointing and vibration isolation. These machines have been predominantly of the Stewart platform, or hexapod, type although other configurations including redundant fast steering mirrors have been considered. A brief history of the program will be followed by an overview of the experimental hardware. Then, UW’s technical contributions will be summarized. These include the following: (1) dynamic modeling of flexure jointed hexapods, (2) decoupled control, (3) fault tolerant pointing and isolation, (4) adaptive cancellation of repetitive vibrations, (5) division of labor among fine and very fine actuators, and (6) geometric design of Stewart platforms and optimization.