bluuebunny/crossref_metadata_2025 huggingface dataset:
A complete survey of Trichoderma chitinases reveals three distinct subgroups of family 18 chitinases
Authors: Seidl Verena , Huemer Birgit , Seiboth Bernhard , Kubicek Christian P.
Published: November 2005

Genome‐wide analysis of chitinase genes in the Hypocrea jecorina (anamorph: Trichoderma reesei) genome database revealed the presence of 18 ORFs encoding putative chitinases, all of them belonging to glycoside hydrolase family 18. Eleven of these encode yet undescribed chitinases. A systematic nomenclature for the H. jecorina chitinases is proposed, which designates the chitinases corresponding to their glycoside hydrolase family and numbers the isoenzymes according to their pI from Chi18‐1 to Chi18‐18. Phylogenetic analysis of H. jecorina chitinases, and those from other filamentous fungi, including hypothetical proteins of annotated fungal genome databases, showed that the fungal chitinases can be divided into three groups: groups A and B (corresponding to class V and III chitinases, respectively) also contained the so Trichoderma chitinases identified to date, whereas a novel group C comprises high molecular weight chitinases that have a domain structure similar to Kluyveromyces lactis killer toxins. Five chitinase genes, representing members of groups A–C, were cloned from the mycoparasitic species H. atroviridis (anamorph: T. atroviride). Transcription of chi18‐10 (belonging to group C) and chi18‐13 (belonging to a novel clade in group B) was triggered upon growth on Rhizoctonia solani cell walls, and during plate confrontation tests with the plant pathogen R. solani. Therefore, group C and the novel clade in group B may contain chitinases of potential relevance for the biocontrol properties of Trichoderma.
Cardiac troponin C‐L29Q, related to hypertrophic cardiomyopathy, hinders the transduction of the protein kinase A dependent phosphorylation signal from cardiac troponin I to C
Authors: Schmidtmann Anja , Lindow Christopher , Villard Sylvie , Heuser Arnd , Mügge Andreas , Geßner Reinhard , Granier Claude , Jaquet Kornelia
Published: November 2005

We investigated structural and functional aspects of the first mutation in TNNC1, coding for the calcium‐binding subunit (cTnC) of cardiac troponin, which was detected in a patient with hypertrophic cardiomyopathy [ Hoffmann B, Schmidt‐Traub H, Perrot A, Osterziel KJ & Gessner R (2001) Hum Mut17, 524]. This mutation leads to a leucine–glutamine exchange at position 29 in the nonfunctional calcium‐binding site of cTnC. Interestingly, the mutation is located in a putative interaction site for the nonphosphorylated N‐terminal arm of cardiac troponin I (cTnI) [ Finley NL, Abbott MB, Abusamhadneh E, Gaponenko V, Dong W, Seabrook G, Howarth JW, Rana M, Solaro RJ, Cheung HC et al. (1999) EJB Lett453, 107–112]. According to peptide array experiments, the nonphosphorylated cTnI arm interacts with cTnC around L29. This interaction is almost abolished by L29Q, as observed upon protein kinase A‐dependent phosphorylation of cTnI at serine 22 and serine 23 in wild‐type troponin. With CD spectroscopy, minor changes are observed in the backbone of Ca2+‐free and Ca2+‐saturated cTnC upon the L29Q replacement. A small, but significant, reduction in calcium sensitivity was detected upon measuring the Ca2+‐dependent actomyosin subfragment 1 (actoS1)‐ATPase activity and the sliding velocity of thin filaments. The maximum actoS1‐ATPase activity, but not the maximum sliding velocity, was significantly enhanced. In addition, we performed our investigations at different levels of protein kinase A‐dependent phosphorylation of cTnI. The in vitro assays mainly showed that the Ca2+ sensitivity of the actoS1‐ATPase activity, and the mean sliding velocity of thin filaments, were no longer affected by protein kinase A‐dependent phosphorylation of cTnI owing to the L29Q exchange in cTnC. The findings imply a hindered transduction of the phosphorylation signal from cTnI to cTnC.
Dynamics of Cage Floating Breakwater
Authors: Murali K. , Amer S. S. , Mani J. S.
Published: November 2005

Floating breakwaters have potential applications in protecting minor ports and harbors such as fisheries and recreational harbors, where-in stringent tranquillity requirements are not warranted. In field applications of the existing floating breakwaters, limitations are imposed due to their large relative width (ratio between breakwater width and wave length) requirements to achieve desirable tranquillity level. This relative width requirement is greater than 0.3 for the existing floating breakwaters. To overcome the above drawback associated with the existing system a new configuration for a floating breakwater is derived, which could yield the desired performance with minimum relative width requirement. The floating breakwater comprises of two pontoons rigidly connected together and each of the pontoons having a row of cylinders attached beneath, for improved performance characteristics. The laboratory tests were conducted in both regular and random wave flumes to study the dynamic behavior of the breakwater. Transmission and reflection coefficients, water surface elevations and velocities inside the cage like area provided in between the pontoons, rigid body motions floating breakwater and mooring forces were studied under regular and random waves and under the regular waves followed by a uniform current. The results proved the suitability of the floating breakwater to the field conditions even for large wave periods. In addition the variations in water particle kinematics, rigid body motion and mooring forces show nominal magnitudes when compared to the existing systems indicating the rigidness of the breakwater.
Experimental Investigation of the Shipping of Water on the Bow of a Containership
Authors: Fonseca Nuno , Guedes Soares C.
Published: November 2005

The paper presents the results of an experimental investigation of the shipping of water on the bow of a containership. Model tests were carried out in head regular and irregular waves of large amplitude, and measurements were taken of: the absolute and relative motions, the structural loads, the height of water and the impact pressure on the deck, and the horizontal impact pressure and total force on the first line of containers on the bow.
Some Experimental Studies of Oscillatory Combustion
Authors: Sage B. H.
Published: November 2005

Measurements of the perturbations in pressure as recorded by flush-mounted transducers during the combustion of mixtures of air and natural gas in a cooled copper tube at atmospheric pressure are reported for a range of mixture ratios. Also presented are the residual quantities of the oxides of nitrogen, as well as the principal components of the products of reaction. The results indicate two stable modes of oscillation. One was found predominantly at mixture ratios above stoichiometric. There was a region near stoichiometric where both modes existed. The quantities of the residual oxides of nitrogen were from 10–30 times as large during oscillatory combustion as during relatively steady combustion. In addition, measurements in a smaller, cooled, copper combustor at pressures up to 50 lb/sq in. absolute are recorded. Again, two stable modes of oscillation were encountered, and the double amplitude of the oscillation for the mode near stoichiometric was nearly five times as great as that away from stoichiometric. The influence of mixture ratio and rates of flow was explored. The quantities of the oxides of nitrogen were determined after quenching the products of reaction at rates of approximately 5° per μsec. Again, the presence of oscillatory combustion appeared to exert a pronounced influence on the presence of oxides of nitrogen. In the case of the high-pressure combustor, the premixed fuel and oxidant were introduced through a supersonic converging-diverging nozzle to avoid coupling between the feed system and the combustor.
Sound Suppression by Electrolytically Generated Bubble Films
Authors: Lewis R. , Fabian R.
Published: November 2005

Under the Foundational Research Program at the Naval Air Development Center, the attenuation characteristics of electrolytically generated bubble films are being investigated experimentally. To date, data have been taken by using random noise and short pulses of sinewave signals propagated through bubble-coated baffles. These results show that the magnitude of attenuation varied with frequency and current density. These findings are in close agreement with results reported by Meyer. The plot of acoustic transmission through the bubble screen vs frequency has a slope of approximately 5.0 dB per octave from 10 through 35 kc/sec. The observed results show qualitatively good agreement with established theories relating to attenuation due to gas bubbles in water (M. Minnaert). Recognizing that the gas films generated by electrolysis vary with different types of water, hydrostatic pressure, temperature, etc., the subject was investigated by reviewing the physical-chemistry literature. The results of these investigations are reported.
Loudness Matching, Detection, and Discrimination of Band-Limited Short Tones
Authors: Creelman c. Douglas
Published: November 2005

With a method of adjustment procedure, observers equated hated 1000-cps sinewave signals, one of which was passed, after hating, through a narrow-band filter. Filtered signals were found to be less loud than unfiltered signals of the same duration. This effect depends on the duration of the signals; at 2 msec, filtered signals are roughly 6 dB below unfiltered signals in loudness. The loudness discrepancy diappears at durations greater than 50 msec. Signal-detection and amplitude-discrimination measures were made separately for filtered and unfiltered signals of 5-msec duration. Amplitude discrimination seems to be superior for unfiltered signals as compared to filtered signals, although the discrepancy is small and hardly sufficient to account for the loudness differences obtained.
Damage-Risk Criterion for Steady-State Noise
Authors: Kryter Kalr D.
Published: November 2005

A probably reasonable damage-risk criterion would be that any sound should not cause an average temporary threshold shift (measured 2 min after exposure) of more than 10 dB at and below 1000 cps, 15 dB at 2000 cps, and 20 dB at and above 3000 cps, in persons with normal hearing. This criterion is relatable to methods proposed for evaluating hearing impairment for speech. To determine what sounds would meet this criterion, subjects with normal hearing were exposed to various octave, 13-octave, and 18-octave bands of noise for durations ranging from 3 min to 8 h. Auditory thresholds were obtained before and after each exposure. Our results for octave bands of noise in the midfrequency range are in close agreement with data obtained by Ward et al. [J. Acoust. Soc. Am. 31, 522–528 (1959)] and Kylin [Acta Oto-Laryngol. Suppl. 51, 152 (1960)]; for octave bands in the low- and high-frequency regions, our results are in some disagreement with previous findings. It was found that the 13-octave bands of noise cause somewhat greater auditory fatigue than do octave bands of noise of equal over-all sound-pressure level having about the same ripper cutoff frequency. [This research was supported by the Office of the Surgeon General, U. S. Army.]
Estimation of Equivalent Freefield Physiological-Noise Levels by Loudness-Balancing Technique
Authors: Piercy J. E. , Shaw E. A. G.
Published: November 2005

There is evidence to suggest that the pressure threshold of hearing at low frequencies is linked with the levels of physiological noise generated by rigid head motion and the inertia of the earphone. The levels in the inner ear due to the inertia of the conductive mechanism itself are, therefore, pertinent to the freefield threshold of hearing, and have been investigated as follows. The subject, whose head is driven by a pure-tone vibrator, adjusts the level of excitation for loudness balance with the ears (a) uncovered and (b) covered by a supraaural or circumaural enclosure. With a supraaural device simulating an MX41AR-TDH39 earphone, the excitation has to be reduced by approximately 18, 30, 25, 25, and 10 dB at 40, 62.5, 125, 250, and 500 cps, respectively. With a 150-cm3 circumaural cavity, the corresponding values are 4–10 dB lower. Subtracting these data from measured levels of physiological noise in aural enclosures and assuming the noise to be generated solely by rigid head motion, one arrives at approximate equivalent freefield physiological-noise levels of 40, 15, 10, −10, and −10 dB re 0.0002 dyn/cm2 at 40, 62.5, 125, 250, and 500 cps, respectively.
Noise Characteristics of a Textile Loom
Authors: Cudworth Allen L.
Published: November 2005

A standard cotton-textile loom has been installed in a semianechoic chamber and a series of measurements made to determine the mechanical actions resulting in sound generation. The instrumentation used to identify and evaluate impulse sounds generated in the loom are described. The measurements made shown that the principal source of noise results from a series of impacts during acceleration and deceleration of the shuttle. Attempts to reduce the noise generated by shuttle impact are discussed.
Attenuation of Rocket-Engine Noise by Water Injection into the Flame Bucket
Authors: Shulman Arnold L.
Published: November 2005

Data are presented from a series of small-scale-model rocket tests conducted to evaluate the acoustic performance of a certain type of water-cooled flame bucket. These data are then compared to hitherto unpublished data from large-scale-engine tests. From a least-square regression analysis, the data indicate an acoustic efficiency (η = Wacoustic/Wmechanical) ranging from 6.24×10−3 for dry operation to 2.04×10−5 for a water flow-rate ratio (ẇ=ẇwater/ẇpropellant) of 5. Nondimensionalized spectra are presented for several representative cases and this information is crossplotted to show the variation of the acoustic efficiency at the characteristic frequency as a function of water flow-rate ratio. Several flame-bucket configurations are described and a novel scheme is shown that achieves the high water flow-rate ratio necessary for effective noise reduction. This system utilizes a large reservoir surrounding the flame bucket. A system of weirs allows a large flow of water to be aspirated into the flame bucket during engine operation. Tests indicated satisfactory operation even when the flame bucket was purposely flooded to simulate failure of the weir mechanism.
Electrostatic Transducers with Solid Dielectric
Authors: Sessler G. M. , West J. E.
Published: November 2005

Recent studies of electrostatic transducers with solid dielectric have led to significant advances in electrostatic transduction. Electrostatic earphones have been constructed with multiple layers of solid dielectric. The use of multiple layers provides a total air gap that is more uniform over the area of the backplate and thus increases sensitivity and decreases mechanical distortion of the unit. The electrical distortion of these earphones can be reduced by use of a push-pull arrangement in which the foils are placed between two perforated metal plates. The external dc bias, which is required in most conventional condenser transducers, can be eliminated by the use of foil electrets. The foil electret is a 14-mil Mylar foil that is prepolarized in a dc field by a special process that is described. Such foil electrets have been used for push-pull earphones, as well as microphones. The use of thin foils in microphones gives a desirable high capacitance. The resulting lower impedance makes it possible to couple the output of the microphone directly to a conventional transistor amplifier. The well-known advantages of conventional condenser transducers are preserved in the described systems.
Cochlear Potential and Eighth-Nerve Action Potential of the Mouse
Authors: Mikaelian D. , Alford Bobby R. , Ruben R. J.
Published: November 2005

Round-window recordings were carried out to determine the range and sensitivity of the cochlear potential of the mouse. The range was found to be from 500 cps to greater than 40 000 cps. Two frequencies, 14 000 and 20 000 cps, had the lowest sensitivity. Sound pressures to give 0.5- and 1-μV responses to all frequencies were determined. The input and output functions of the mouse cochlea were also determined. Studies were done on overloading in the mouse's cochlea. The eighth-nerve action potential was recorded from the round window and from the eighth nerve. An N1N2 was observed. The mouse appears to be similar to other animals in respect to its cochlear dynamics and characteristics of the eighth-nerve action potential.
Single-Unit Responses to Sound in the Eighth Nerve of Mouse
Authors: Finck A. , Ruben R. J.
Published: November 2005

Tungsten microelectrodes were placed into the eighth nerve of the mouse (CBA). More than 100 units were studied with respect to their spontaneous and driven activity. The composite of all obtained unit response areas ranged from 300–40 000 cps (no stimuli greater than 40 000 cycles were used). Impulse threshold at the composite characteristic frequency was 8 dB re 0.0002 dyn/cm2 at 14 000 cps. Some relationships between unit response patterns, stimulus intensity, and characteristic frequency are presented. Data are presented that demonstrate unit firing patterns to the envelope of two simultaneous tones.
Relationship between the Physiological and Behavioral Response to Sound in Mouse
Authors: Ruben R. J. , Warfield Dickens , Glackin R. , Finck A. , Mikaelian D. , Alford Bobby R.
Published: November 2005

The absolute hearing thresholds of the mouse have been determined. Under similar conditions in the same laboratory, the thresholds for the single-unit eighth-nerve fiber have been determined. Also, under similar conditions, the cochlear potential from the round-window membrane has been studied. The experiments indicate that the 0.5-μV-response level of the cochlear potential corresponded closely to the range and sensitivity of the threshold for the single units of the eighth nerve. Both of these values were similar to the absolute behavioral thresholds found in the mouse. There are certain discrepancies in the three sets of observations. These are discussed and evaluated in terms of the technical difficulties in the experiments. The physiological response as a measure of behavioral thresholds is discussed. The correlation between hearing thresholds in human and cochlear potentials is also discussed.
Voiceless-Fricative Identification as a Function of Duration Modification
Authors: Barrs James T.
Published: November 2005

A duration-modification study was made on the voiceless initial fricatives /f/, /s/, and /∫/, followed each by the vowels /a/, /i/, /u/, /ɪ/, and /Λ/, of certain nonsense CVC syllables of clear speech. The final fricative and varying amounts of the initial fricative were suppressed. The resulting signals were presented to listeners, and certain systematic changes in phoneme identity were reported by them. Typically, voiceless fricatives, when abbreviated, appear to become voiceless stops and, when further abbreviated, become voiced stops. Statistical results of this study of apparent changes in phoneme identity as a function of the duration of the omitted or remaining portion of the initial fricative are reported. [The research reported in this paper was supported by the U. S. Air Force Cambridge Research Laboratories, Office of Aerospace Research, under Contract AF 19(628)-389.]
Physical Measurements on Equally Speech-Interfering Navy Noises
Authors: Klumpp R. G. , Webster J. C.
Published: November 2005

Noise measurements and recordings were made on board several ships. Speech interference level (SIL) calculations showed that the median noise levels were above SIL's recommended for habitable offices. Eleven diverse ship noises were edited out and added to two office noises and three laboratory thermal noises. The level of each of these 16 noises was adjusted so that loudspeaker-reproduced Rhyme words at a level of 78 dB at 1 m were reduced to 50 % word intelligibility. Various spectrum analyses (octave band and 20-cps band), physical measurements (C, B, A, DIN 3 sound-level meter weightings), calculations [SIL's and 6-octave weighted articulation index (AI)], and fittings (to noise-criteria-type curves) were done to find which method came closest to agreeing that the noises were equally speech-interfering. Averaging methods like the AI or the SIL gave the best agreement. The A or DIN 3 frequency-weighting networks were next best and the curve-fitting procedures and the B & C sound-level-weighting networks were the poorest.
Operating Characteristics from Yes-No and Forced-Choice Procedures
Authors: Schulman Arthur I. , Mitchell Rhoda R.
Published: November 2005

Operating characteristics were obtained from yes-no (YN) and two-alternative forced-choice (2AFC) experiments in auditory signal detection. Four listeners used a six-point scale of confidence ratings with each of these psychophysical methods. An extreme rating (1 or 6) indicated high confidence that the signal was or was not presented (in YN) or that the signal occurred in the first- or second-observation interval (in 2AFC). Note that response bias, occasionally exhibited by listeners in 2AFC, and which affects the proportion of correct judgments when conventional binary decisions are made, is of lesser concern when confidence ratings are used and operating characteristics obtained. The signal was a sinuosid of 1000 cps presented for 0.1 sec against a continuous background of noise. Testing was conducted at E/N0's of 7.9 and 15.8. The values of the detectability parameters of the operating characteristics obtained in 2AFC were generally very close to predicted values based upon performance in YN. It would be hazardous, of course, to predict d′ in YN on the basis of performance in 2AFC, since it is not always safe to assume that the operating characteristic to be obtained in YN will have unit slope when plotted on normal-normal coordinate paper.
Lead as a Ceiling Barrier for Sound
Authors: Goodfriend Lewis S.
Published: November 2005

Sound isolation between offices having a common plenum above an acoustical ceiling can be improved considerably by means of a lightweight lead-sheet backing. 1-lb/sq ft lead sheet was laid between runners in an acoustical ceiling over relatively light and relatively dense acoustical ceiling boards. With the denser ceiling board, an improvement averaging 7 dB at the 11 standard test frequencies from 125–4000 cps resulted, with a maximum increase of 15 dB at 1400 cps. With the lighter ceiling board, the increase averaged 18 dB with a maximum increase of 30 dB at 2800 cps. [This work was supported by the Lead Industries Association-Expanded Research Program.]
Speaker Recognition in Speech Communications
Authors: Holmgren G. L. , Morrison E. J.
Published: November 2005

A study was performed to investigate the definition of a perceptual space within which listeners locate voices, to the end that the effects o[ manipulating speaker, hardware, and listener characteristics can be measured, and, eventually, that specifications for elements of a voice-communications system might be prepared to produce the desired system characteristic. In the experiments reported, taped speech samples were rated by listeners, using Osgood's semantic differential method. Previous study indicated only four basic dimensions were required to account for ratings given speakers on a large number of characteristics. In a second experiment, a reduced number of characteristics, selected from the original list as best representing the four necessary factors, was used by listeners to rate recorded speaker samples. The experimental design allowed examination of the effects on ratings due to differences between listeners, due to repetition of the rating task, and to order of speaker presentation. Results of these examinations and the following are presented: (1) adequacy of the original factors in accounting for listeners' ratings; (2) differentiation between speakers; (3) reliability of ratings; and (4) familiarity of previously unheard voices. [This research was supported by AFCRL (OAR) under Contract AF19(628)-345.]
Plate-Damping due to Thicknesswise Deformations in Attached Viscoelastic Layer
Authors: Ungar Eric E. , Kerwin Edward M.
Published: November 2005

Energy dissipation due to thicknesswise motion of viscoelastic layers attached to plates is analyzed in order to supplement previous analyses of damping due to shear, flexural, and in-plane extensional motions. It is shown that the thicknesswise motion may constitute an important damping mechanism. This is particularly true for relatively soft and thick viscoelastic layers at frequencies corresponding to standing-wave resonances in the damping layer. The general behavior of thickness-compression damping layers is discussed on the basis of a relatively simple analysis, and reasonable agreement between theory and experimental results is demonstrated. [This work was supported by the U. S. Navy, Bureau of Ships.]
Partial Masking of Pure Tones by a Narrow Band of Noise
Authors: Scharf Bertram
Published: November 2005

A noise, one critical band wide and centered at 980 cps, was used to mask a tone. The tone, at one or another of five frequencies that ranged in steps of one critical band from 690–1355 cps, was presented at 25, 45, 65, and 85 dB SPL. Its loudness level was measured as a function of the SPL of the masking noise. As the SPL of the noise was decreased, tones lying below the frequency range of the noise increased in loudness from threshold level more slowly than did tones lying above the noise; the low-frequency tones required about twice as much reduction in the SPL of the noise to reach their full unmasked loudness level. Except near threshold, the noise thus reduced the loudness of the low-frequency tones more than that of the high, but the noise raised the threshold for the high-frequency tones more. The reversal of the asymmetry of masking when the masking becomes partial may be accounted for if we assume an unchanging asymmetry in the excitation patterns evoked by the stimuli within the auditory system. [This research was conducted at the Institut f̈r Nachrichtentechnik of the Technische Hochschule Stuttgart under a grant from the Deutsche Forschungsgemeinschaft.]
Formant-Period Tracker
Authors: Campanella S. Joseph , Coulter David C.
Published: November 2005

One of the principal problem areas in the perfection of the formant-tracker speech-compression system lies in the extraction with the utmost of precision of the formant traces that are pertinent to the preservation in speech of the articulatory events. Under a current research effort [sponsored by the U. S. Army Signal Research and Development Laboratory under Contract DA-36-039-AMC-00006(E)], a number of new methods for achieving such precision in formant tracking have been studied. One of these, which we have called the “Formant Period Tracker,” has shown great promise in achieving this desired goal. This paper discusses the technique, a theoretical evaluation of the technique applied to certain isolated utterances and a means of implementing the technique.
On Segmentation of Speech for Automatic Speech Recognition
Authors: Otten Klaus W. , Zimmerle Donald F. , Hemami Hooshang
Published: November 2005

The principles of speech segmentation are explained. Methods for the segmentation of speech into thought elements, words, syllables, phonemes, and acoustical (subphonemic) sound elements are discussed. The results of experimental segmentation of speech with a digital computer (as part of a speech-recognition simulation program sponsored by the U. S. Air Force) on the thought-element, syllable, and acoustical sound-element level are presented. Based on experimental segmentation data, it is attempted to show that two basically different types of segmentation must be performed in the conversion of continuous speech into a written transcription. One type is that of quasinatural segmentations. It can be achieved directly by analyzing the acoustical signal; examples are the segmentation into thought elements, syllables, and subphonemic sound elements. The other type synthesizes from the quasinatural-speech segmentation those segmentations that are of importance for the written transcription. These segmentations by synthesis utilize information on (sequential) statistics and the structure of the language; examples are phoneme and word segmentation.
Correlation Hypothesis to Explain the Fine Frequency Discrimination of the Ear
Authors: Karplus Henry B.
Published: November 2005

Earlier suggestions to reconcile the observed broad frequency-displacement function of the basilar membrane and the subjective high discrimination of the hearing mechanism seek an explanation in possible neural interaction and mutual suppression of less strongly stimulated neurons in the vicinity of more strongly stimulated neighbors. This explanation leaves questions on the hearing of combinations of tones in doubt. A mechanism is postulated based on the traveling-wave nature of the disturbance of the membrane. In the vicinity of the maximum of the displacement, the wavevelocity of the disturbance on the membrane is a sharp function of frequency. Many hair cells are assumed to be excited in phase with the local displacement, and signals passing from a receptor closer to the stapes are delayed in time with respect to the signal from the more apical receptors. Delays due to neuron pathlength are assumed to be an exact replica of the time delay of the signal along the membrane, for a specific frequency. Different delay-line characteristics in a given region of the membrane would, therefore, produce simultaneity of pulses at separate synapses for slightly different frequencies. Plausibility of this hypothesis is greatly enhanced by the observation that the phase velocity of the traveling wave on the basilar membrane at the point of maximum displacement is very close to the velocity of signals along unmyelinated nerve fibers, so that the latter could act in exactly the manner postulated. [This work was supported by the Electromagnetic Warfare and Communications Laboratory, Aeronautical Systems Division.]
Three-Dimensional Ray-Tracing through Internal Waves
Authors: Maunsell C. D.
Published: November 2005

Most published ray-tracing procedures assume that the local speed of sound in the sea is a function of depth alone. Lee [J. Acoust. Soc. Am. 33, 671 (1961)] has published results obtained by tracing rays lying in a vertical plane normal to the crests of an internal wavesystem in which both vertical and horizontal gradients are present. Rays starting in vertical planes not normal to the wavecrests will suffer horizontal as well as vertical refraction. The equations necessary to handle this three-dimensional problem are not significantly harder to integrate numerically than those used by Lee. A program has been written for a PB-250 computer to trace rays in three dimensions through a similar internal wavesystem. A number of cases are being evaluated to estimate the magnitude of the three-dimensional effects.
Discussion of Measured Intensity Fields from Ocean-Bottom Returns
Authors: Hurdle Burton G. , Flowers Kenneth D.
Published: November 2005

A comparison has been made between the measured intensity fields, reported in paper BB5, and predicted fields based on two models. These models are representations of geometric reflection and Lambert's law scattering from a surface. The comparisons indicate that the measured fields do not correspond to either model. Further, the measured fields do not appear to correspond to a combination of the two models. When consideration is given to the shape of the plots of the measured field, combined with data indicating significant acoustic penetration into the bottom and data on the quantity of energy penetrating, it is suggested that a significant contribution to the field is made by a transmission path through the bottom. The possibilities of contributions by bottom paths, in light of existing sediment-attenuation data in this frequency range, are discussed.
Coherence Estimates in the Case of Multipath Transmission
Authors: Shapiro A.
Published: November 2005

It is now accepted that the ocean acts as a randomly inhomogeneous medium for the transmission of acoustic waves. One of the standard techniques used to study the nature of the distortions introduced by the medium is to measure the coherence between the signal received on a hydrophone and a replica of the transmitted signal. In the case where the received signal is a sum of separate arrivals, however, the usual estimate of coherence, that is, the modulus of the sample cross spectrum divided by the product of the sample spectra, yields results that deny one's intuition. Alternate estimates of coherence are presented and discussed in an attempt to obviate this difficulty. [This work was supported by the Office of Naval Research, U. S. Navy.]
Ambient Sea-Noise Model
Authors: Talham R. J.
Published: November 2005

Assuming a surface distribution of noise sources, a model of ambient sea noise is developed. Volume absorption and the effects of refraction and reflection over long-range paths are included. Thus, account is taken of the facts that the energy from a given source element can arrive at a point over many paths and that the energy from many sources can arrive at a point over the same terminal path. The derived directional noise field is expressed as a function of vertical arrival angle with velocity profile, surface distribution, bottom reflection coefficient, and frequency as parameters. In an example representative of deep-water conditions, it is found that most of the low-frequency acoustic energy at the ocean bottom arrives over nearly horizontal paths. The spectrum predicted by the model is compared to observed spectra and found to be in essential agreement By discriminating against large vertical angles, a low-frequency, upward-looking, bottom-mounted array could attain an appreciable gain. [This work was supported by the Bureau of Ships, U. S. Navy.]
Acoustical Design of the New Seattle Opera House
Authors: Veneklasen Paul S. , Christoff Jerry
Published: November 2005

Acoustical-design features and measured performance are described. Seating capacity is 3100, volume is 778 000 cu. ft., nominal reverberation time is 2.0 sec, adjustable by wall louvers.
Terminal-Analog Synthesis of Voiced Fricatives
Authors: Maxey H. D.
Published: November 2005

A voiced fricative differs from the corresponding voiceless fricative in two important ways: (1) it has a low-intensity voiced-formant structure and (2) its characteristic noise spectrum is amplitude-modulated by the action of the glottis. A common method of synthesizing voiced fricatives has been to superimpose a voiced-formant structure on the noise spectrum of the corresponding voiceless fricative, satisfying condition (1) but not condition (2). The resulting sounds have acceptable voice-voiceless distinctions but lack naturalness. A second method, which also includes the amplitude modulation of the noise spectrum, has been judged by informal listening to substantially improve the naturalness of synthetic voiced fricatives. A method is described for modulating the noise with the buzz source in a terminal-analog synthesizer. A major requirement is that the perceptual depth of modulation be independent of the buzz frequency. A comparison is made between natural speech and the above two methods of synthesizing voiced fricatives with a terminal analog.
Short-Time “Cepstrum” Pitch Detection
Authors: Noll A. M. , Schroeder M. R.
Published: November 2005

A short-time cepstrum analyzer for vocal-pitch detection has been simulated on an IBM-7094 digital computer. (The cepstrum of a signal is defined as the square of the Fourier transform of the logarithm of the amplitude spectrum of the signal.) Since temporal periodicities in a speech signal cause periodic ripples in the amplitude spectrum, Fourier transformation of the spectrum gives the “frequency” of the ripple, which is inversely proportional to the fundamental frequency of the speech. Taking the logarithm of the amplitude spectrum makes the effects of the vocal tract (spectrum envelope) and the vocal source (spectrum fine structure) additive, thereby separating the low “frequencies” of the spectrum envelope from the usually higher frequencies of the spectrum fine structure. Cepstrum pitch detection is insensitive to phase distortion, amplitude distortion, additive noise, and the absence of the fundamental speech frequency. A general description of the technique and some recent results and examples are given.
Thresholds of Audition for Three Species of Monkey
Authors: Fujita Shiro , Elliott D. N.
Published: November 2005

Behaviorally determined thresholds of audition for three species of monkey (squirrel, rhesus, and cynamolgus) are reported. Three different testing procedures were utilized for measuring the threshold: namely, avoidance conditioning in a double-grill cage and bar-pressing procedures with reward and avoidance reinforcements. There was good agreement among the audiograms obtained for various species despite the different conditioning procedures used.
Model for Specification of the Vocal-Tract Area Function
Authors: Coker Cecil H. , Fujimura Osamu
Published: November 2005

A geometrical model is described which approximates typical vocal-tract area functions with reasonable accuracy for both vowels and consonants. The articulatory configuration is completely determined by five variables. The two-dimensional position of a circle representing the tongue is specified within a fixed larger circle representing the palate and part of the pharyngeal wall. The lower part of the pharynx is represented by a piecewise linear function that is derived from the tongue position. An additional variable specifies a deviation from the circle simulating an independent control of the tongue-tip position. The extents of labial opening and protrusion are represented by two additional variables. A digital computer is programmed to derive area functions from these variables, to calculate formant frequencies, and to drive a hardware terminal-analog synthesizer.
Automatic Grapheme-to-Phoneme Translation of English
Authors: Lee Francis F.
Published: November 2005

In the design of a machine that scans printed-English text and generates the corresponding spoken output with virtually no restriction on the vocabulary size, a procedure for the translation of the graphemes to the phonemes is necessary. Translation technique using the letter context alone, such as is used in the phonic method of teaching English to children, is shown to be entirely unsatisfactory. Instead, by the use of morphographemic rules, written words are decomposed into their constituent morphs and the corresponding morphemes are looked up in a morph-morpheme lexicon. Morphophonemic rules are used to produce the output-phoneme string for the given word. Syntactic markers, stored as part of the lexicon entries, can be used to resolve certain ambiguities and to perform sentence parsing, which is necessary in the assignment of suprasegmental phoneme values. Engineering considerations in the implementation are discussed. [This work was supported by a grant from the National Institutes of Health and by a Joint Services Electronics Program Contract.]
Accelerated Cell Death in
Podospora
Autophagy Mutants
Authors: Pinan-Lucarré Bérangère , Balguerie Axelle , Clavé Corinne
Published: November 2005

Although autophagy is characteristic of type II programmed cell death (PCD), its role in cell death is currently debated. Both cell death-promoting and prosurvival roles of autophagy have been reported depending on the organism and the cell type. In filamentous fungi, a cell death reaction known as an incompatibility reaction occurs when cells of unlike genotype fuse. Cell death by incompatibility is characterized by a dramatic vacuolar enlargement and cell lysis. In
Podospora anserina
, autophagy is induced early during this cell death reaction. Cell death by incompatibility in
Podospora
is a model of type II PCD used here to assess the role of autophagy in this type of cell death. We have inactivated Pa
ATG1
, the
Podospora
ortholog of the
Saccharomyces cerevisiae ATG1
gene involved in the early steps of autophagy in yeast. The ΔPa
ATG1
mutant displays developmental defects characteristic of abrogated autophagy in
Podospora
. Using the green fluorescent protein-PaATG8 autophagosome marker, we show that autophagy is abolished in this mutant. Neither cell death by incompatibility nor vacuolization are suppressed in ΔPa
ATG1
and ΔPa
ATG8
autophagy mutants, indicating that a vacuolar cell death reaction without autophagy occurs in
Podospora
. Our results thus provide a novel example of a type II PCD reaction in which autophagy is not the cause of cell death. In addition, we found that cell death is accelerated in ΔPa
ATG
null mutants, suggesting that autophagy has a protective role in this type II PCD reaction.
Involvement of a Short Interspersed Element in Epigenetic Transcriptional Silencing of the Amoebapore Gene in
Entamoeba histolytica
Authors: Anbar Michael , Bracha Rivka , Nuchamowitz Yael , Li Yan , Florentin Anat , Mirelman David
Published: November 2005

Transcriptional silencing of an amoebapore (
ap-a
) gene occurred in
Entamoeba histolytica
following the transfection of plasmids containing a DNA segment (473 bp) homologous to the 5′ upstream region of the gene (R. Bracha, Y. Nuchamowitz, and D. Mirelman, Eukaryot. Cell
2:
295-305, 2003). This segment contains the promoter region of the
ap-a
gene, a T-rich stretch, followed by a truncated SINE1 (short interspersed element 1) that is transcribed from the antisense strand. Transfection of plasmids containing truncated SINE1 sequences which lack their 3′ regulatory elements upstream of the
ap-a
gene was essential for the downstream silencing of the
ap-a
gene while transfection with plasmids containing the entire SINE1 sequence or without the T-rich stretch promoted the overexpression of the
ap-a
gene. Both the T-rich stretch and sequences of the 5′ SINE1 were essential for the transcription of SINE1. RNA extracts from gene-silenced cultures showed small amounts of short (∼140-nucleotide), single-stranded molecules with homology to SINE1 but no short interfering RNA. Chromatin immunoprecipitation analysis with an antibody against methylated K4 of histone H3 showed a demethylation of K4 at the domain of the
ap-a
gene, indicating transcriptional inactivation. These results suggest the involvement of SINE1 in triggering the gene silencing and the role of histone modification in its epigenetic maintenance.
Stress-Activated Protein Kinase Pathway Functions To Support Protein Synthesis and Translational Adaptation in Response to Environmental Stress in Fission Yeast
Authors: Dunand-Sauthier Isabelle , Walker Carol A. , Narasimhan Jana , Pearce Amanda K. , Wek Ronald C. , Humphrey Tim C.
Published: November 2005

The stress-activated protein kinase (SAPK) pathway plays a central role in coordinating gene expression in response to diverse environmental stress stimuli. We examined the role of this pathway in the translational response to stress in
Schizosaccharomyces pombe
. Exposing wild-type cells to osmotic stress (KCl) resulted in a rapid but transient reduction in protein synthesis. Protein synthesis was further reduced in mutants disrupting the SAPK pathway, including the mitogen-activated protein kinase Wis1 or the mitogen-activated protein kinase Spc1/Sty1, suggesting a role for these stress response factors in this translational control. Further polysome analyses revealed a role for Spc1 in supporting translation initiation during osmotic stress, and additionally in facilitating translational adaptation. Exposure to oxidative stress (H
2
O
2
) resulted in a striking reduction in translation initiation in wild-type cells, which was further reduced in
spc1
−
cells. Reduced translation initiation correlated with phosphorylation of the α subunit of eukaryotic initiation factor 2 (eIF2α) in wild-type cells. Disruption of Wis1 or Spc1 kinase or the downstream bZip transcription factors Atf1 and Pap1 resulted in a marked increase in eIF2α phosphorylation which was dependent on the eIF2α kinases Hri2 and Gcn2. These findings suggest a role for the SAPK pathway in supporting translation initiation and facilitating adaptation to environmental stress in part through reducing eIF2α phosphorylation in fission yeast.
N-Terminal Arm of Mcm1 Is Required for Transcription of a Subset of Genes Involved in Maintenance of the Cell Wall
Authors: Abraham Deepu S. , Vershon Andrew K.
Published: November 2005

The yeast Mcm1 protein is a member of the MADS box family of transcription factors that interacts with several cofactors to differentially regulate genes involved in cell-type determination, mating, cell cycle control and arginine metabolism. Residues 18 to 96 of the protein, which form the core DNA-binding domain of Mcm1, are sufficient to carry out many Mcm1-dependent functions. However, deletion of residues 2 to 17, which form the nonessential N-terminal (NT) arm, confers a salt-sensitive phenotype, suggesting that the NT arm is required for the activation of salt response genes. We used a strategy that combined information from the mutational analysis of the Mcm1-binding site with microarray expression data under salt stress conditions to identify a new subset of Mcm1-regulated genes. Northern blot analysis showed that the transcript levels of several genes encoding associated with the cell wall, especially
YGP1
, decrease significantly upon deletion of the Mcm1 NT arm. Deletion of the Mcm1 NT arm results in a calcofluor white-sensitive phenotype, which is often associated with defects in transcription of cell wall genes. In addition, the deletion makes cells sensitive to CaCl
2
and alkaline pH. We found that the defect caused by removal of the NT arm is not due to changes in Mcm1 protein level, stability, DNA-binding affinity, or DNA bending. This suggests that residues 2 to 17 of Mcm1 may be involved in recruiting a cofactor to the promoters of these genes to activate transcription.
Activation of AP-1-Dependent Transcription by a Truncated Translation Initiation Factor
Authors: Jenkins Caroline C. L. , Mata Juan , Crane Richard F. , Thomas Benjamin , Akoulitchev Alexandre , Bähler Jürg , Norbury Chris J.
Published: November 2005

Int6/eIF3e is a highly conserved subunit of eukaryotic translation initiation factor 3 (eIF3) that has also been reported to interact with subunits of the proteasome and the COP9 signalosome. Overexpression of full-length Int6 or a 13-kDa C-terminal fragment, Int6CT, in the fission yeast
Schizosaccharomyces pombe
causes multidrug resistance that requires the otherwise inessential AP-1 transcription factor Pap1. Here we show for the first time that Int6CT acts to increase the transcriptional activity of Pap1. Microarray hybridization data indicate that Int6CT overexpression resulted in the up-regulation of 67 genes; this expression profile closely matched that of cells overexpressing Pap1. Analysis of the upstream regulatory sequences of these genes showed that the majority contained AP-1 consensus binding sites. Partial defects in ubiquitin-dependent proteolysis have been suggested to confer Pap1-dependent multidrug resistance, but no such defect was seen on Int6CT overexpression. Indeed, none of the previously identified interactions of endogenous Int6 was required for the activation of Pap1 transcription described here. Moreover, Int6CT-induced activation of Pap1-responsive gene expression was independent of the ability of Pap1 to undergo a redox-regulated conformational change which mediates its relocalization to the nucleus and expression of oxidative stress response genes. Int6CT therefore activates Pap1-dependent transcription by a novel mechanism.