bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical oceanographic and acoustical results from the 1988–89 Greenland Sea tomography experiment
Authors: Lynch James F. , Worcester Peter F. , Pawlowicz Richard , Morawitz Werner , Sutton Philip J. , Jin Guoliang
Published: October 2005

Analyses of the acoustical tomography data taken in the Greenland Sea in 1988–1989, when combined with inputs from other environmental measurements made in the region, have yielded a number of insights into both the physical oceanographic and acoustical properties of that polar sea. The formation of Greenland Sea deep water (GSDW), which is of importance to the global heat engine and climate studies, was imaged tomographically, allowing us to make significant new statements about the mechanisms, rates, and amounts of GSDW formation. Studies of the late arriving acoustic energy have allowed both detailed studies of the evolution of the surface mixed layer as well as a novel acoustical study of the temporal dispersion of acoustic normal modes by that layer in the marginal ice zone. Rough surface scattering processes in ice and open water conditions, as well as ambient noise, have also been studied using the tomography data set.
Modal inversion for bottom sound-speed profile in shallow Arctic waters using broadband signals
Authors: Yang T. C. , Yates T.
Published: October 2005

Acoustic inversion of geoacoustic properties in the ocean bottom has been investigated recently using matched-field processing. In the shallow Arctic waters, the acoustic signal may still be dominated by waterborne modes. As a consequence, the matched-field correlation may not be very sensitive to bottom sound-speed variation. It is found that in a water depth of approximately 600 m the matched-field correlation remains very high (≳0.95) even with a mismatch of 50 m/s in bottom sound-speed profile. To improve the sensitivity to bottom mismatch, we include only the high-order modes in the matched-field/mode correlation. This method is investigated using a simulated broadband signal and also using SUS data received on a vertical array. The source is localized using broadband matched-field/mode processing. Short-range data are considered to maximize bottom interacting signals.
Numerical modeling of long-range low-frequency propagation in irregular Arctic waveguide
Authors: Gavrilov A. N. , Kryazhev F. I. , Kudryashov V. M.
Published: October 2005

An improved model of the Arctic ice cover and the mode coupling approach have been used for numerical calculations of low-frequency sound propagation over the irregular trans-Arctic paths proposed for acoustic monitoring of Arctic climate change. The ice cover was represented by a rough elastic layer with the roughness statistically determined by its spatial spectrum and correlation between the upper and lower ice surfaces. Horizontal change of the ice statistics along the supposed paths was approximated by a step function in accordance with existing data. The bottom relief and horizontal variation of the typical sound speed profile were approximated by segment-linear functions. In the ice modeling particular attention has been given to the influence of the ice cracks on low-frequency propagation loss. This can be regarded as a shear wave attenuation in the broken ice plate which differs strongly from shear wave absorption in normal ice and mainly depends on a mean size of the ice fields. Calculated acoustic propagation loss over the trans-Arctic paths differ from the empirical to experimental data after a 1000-km distance, with the calculated loss significantly less than the empirical prediction. This is caused by a relative increase of the deep-water mode contribution to the total sound field at such long distances.
Azimuthal variation of low-frequency Bragg scattering from the ocean surface
Authors: Hayek C. S. , Schurman I. W. , Boyles C. A. , Sweeney J. H.
Published: October 2005

Low-frequency sound, backscattered from an annulus of ocean approximately 9 km wide at a nominal 43-km range, was measured on a 128-hydrophone horizontal line array (HLA) during an experiment in the Gulf of Alaska. Fourier analysis of the backscattered signal permitted separation of the Bragg-shifted returns from the 250-Hz carrier frequency. The Bragg-reflected energy was resolved in azimuth by beamforming the HLA data. Azimuthally varying sea surface backscattering strengths, corresponding to measured wind speeds, were obtained using an exact solution for the backscattered field applied to a two-dimensional Donelan water wave spectrum. Normal mode model predictions using the calculated scattering strengths agreed with the up- and down-shifted Bragg energy measurements in both level and azimuthal dependence. [Work supported by SPAWAR PMW 192.]
Meeting room design—An architect’s perspective
Authors: Fentress Curtis Worth
Published: October 2005

C. W. Fentress J. H. Bradburn and Associates was the lead designer for the Colorado Convention Center, Jefferson County Court Building, and for two new airport passenger terminals in Denver and Seoul. From the architect’s perspective, there are many considerations in the design of meeting spaces. The author, Principal in Charge of Design, will share his insight into what clients want in design, and what clients think is important to their customers. Acoustics and noise issues are discussed in the context of the overall design project.
Optimal heat-driven thermoacoustic refrigeration: The beer cooler revisited
Authors: Arnott W. Patrick , Atchley Anthony A.
Published: October 2005

The goals of this research are to design and build an optimally efficient heat-driven thermoacoustic refrigerator to cool a given heat load to a desired temperature. The system uses heat to drive a thermoacoustic prime mover that produces sound for a thermoacoustic refrigerator (as originally investigated by John Wheatley in a device he called a beer cooler on account of the temperatures and heat loads he was striving to obtain). Here, the first step, numerical design, is described. A given system configuration is analyzed using Runge–Kutta integration of three coupled DE’s for ambient temperature, acoustic pressure, and specific acoustic impedance (SAI) in the prime mover and refrigerator and using pressure plus SAI transition equations elsewhere. Complex eigenfrequency analysis is used to obtain starting values for a root finding routine for the systems opening acoustic pressure, hot end temperature, heat load, and frequency. Optimization is used to find a system configuration that maximizes overall efficiency. These calculations should shed new insight into optimal heat exchanger lengths. Progress on meeting these goals is reported. The basic set of equations used in the Runge–Kutta integration have intriguing forms and are discussed. Emphasis is placed on investigation of the coupling between prime mover and refrigerator operation. [Work supported by ONR.]
Modular thermoacoustic refrigerator
Authors: Murrell Steven R. , Mozurkewich George
Published: October 2005

A thermoacoustic refrigerator was built to explore scaling to large heat flux. The refrigerator was constructed according to a modular design so that various stack, heat exchanger, and resonator sections are easily interchangeable. The resonator is driven by a commercial 10-in. woofer. Initial tests, using pure helium gas as the working fluid and steel honeycomb (0.8-mm cell) for the stack, pumped 60 W of heat against a 10 °C temperature gradient. Measurements of heat flux and efficiency will be reported as functions of stack structure (e.g., pore size and shape) and will be compared with theoretical predictions.
Relating Arctic ambient noise to thermally induced fracturing of the pack ice—An ability to monitor climate change?
Authors: Lewis James K.
Published: October 2005

Thermally induced fracturing of pack ice can be simulated using a viscoelastic model and a fracturing paradigm for predicting the stress state of the ice. Under a given set of circumstances, the fracturing paradigm simulates conditions that exceed the tensile strength of the ice as well as the associated stress relief as a result of fracturing. The thermal stress–ice fracturing model was used to produce a fracture count time history for the ice pack during the fall of 1988 in the eastern Arctic Ocean. The count was compared to the observed 500-Hz under-ice noise in which 13 distinct noise episodes were identified. The simulation showed increases in predicted fracturing levels for 11 of the 13 noise episodes. Some of the fracturing was associated with nightly cooling. Others occurred as a result of sustained cooling over several days following the passage of cold fronts. The stress–fracturing model can be used to study changes in under-ice noise as a result of global warming. Examples are presented based on warming as predicted by various climate models. The results indicate that climate changes could be monitored using winter-time under-ice ambient noise observations from the Arctic.
Speech production: Thirty years after
Authors: House Arthur S. , Stevens Kenneth N.
Published: October 2005

Measurements have been made on a corpus of bisyllabic nonsense utterances spoken by three adult male talkers on two occasions separated by 30 years. The 1960 and 1990 recordings were processed similarly so that comparisons could be made directly. Some primary and secondary characteristics of vowels were measured: duration, fundamental frequency and the frequencies of F1 and F2. The durations of prestressed consonants were measured, and vowel–consonant amplitude ratios computed. Long-term spectra of the talkers were examined and some informal listening comparisons were made. Spectrograms of some samples were studied, and statistical analyses, when appropriate, were made. Results indicate that the talkers’ productions were remarkably consistent over 30 years. Over time the talkers’ mean vocalic duration (10 vowels) shortened (6 ms); their mean vocalic fundamental frequency rose (7 Hz); their mean frequencies of F1 and F2 (10 vowels) descended (15 and 26 Hz, respectively); their mean (initial) fricative duration lengthened (12 ms); and, their mean (initial) stop duration lengthened (hold portion, 15 ms; release portion, 5 ms). Interactions were usually significant: individual talkers’ changes in duration, formant frequencies; and fundamental frequency were not identical. Patterns of duration and fundamental frequency in the set of vowels, however, were stable over time.
Motor equivalence in the transformation from vocal-tract configurations to the acoustic transfer function: Adaptation to a bite block
Authors: Perkell J. S. , Matthies M. L. , Svirsky M. A. , Jordan M. I.
Published: October 2005

In a preliminary study [Perkell etal., J. Acoust. Soc. Am. 93, 2948 (1993)] subjects demonstrated a trading relation (negative correlations) between tongue-body raising and lip protrusion in production of the vowel /u/. Data analyses indicated an increased tendency for the trading relation to occur at high values of F2. The tentative hypothesis is that when more than one articulator contributes to producing a particular acoustic cue and a source of variation displaces one of the articulators away from its target, compensating (complementary) adjustments are made in the programmed displacements of the other contributing articulator(s) to help constrain the acoustic variation. These adjustments should be more strongly expressed in tokens that are close to phonemic boundaries, where variation in the displacement of one of the contributing articulators could result in production of the wrong sound. This work has been extended with two new subjects. halfway through the experiment a bite block was placed in the subject’s mouth to introduce an additional source of variation. One subject strictly used coordination (i.e., positive correlation) to produce /u/ and did not alter this strategy with the bite block. Negative correlations were found for the other subject in subsets with relatively high values of F2. [Work supported by NIDCD.]
Duration aspects in manner of articulation distinctions
Authors: Romero Joaquín
Published: October 2005

Differences in manner of articulation—between stops, fricatives, and approximants—have been described articulatorily in terms of degree and area of the constriction. It is suggested here that such differences are generally accompanied by a distinction in the duration of the constriction gestures. An experiment was carried out in which an optical tracking device was used to record the movement of the lips of a speaker of Andalusian Spanish, a dialect spoken in Southern Spain that has a complete series of homorganic stops, fricatives, and approximants. Results of both acoustic and kinematic analyses indicated that, while certain variation in constriction degree was indeed observed, the durational differences appeared to be much more stable and robust. A bilabial fricative [β] not only has a narrower constriction than an approximant βlower modifier but is also longer. Fricatives, because they need to generate turbulent airflow, have a longer, more precise articulatory configuration than approximants, which create no turbulence and, consequently, need not remain in a particular articulatory configuration for long. Because of their very short duration, approximants seem to lack a precise articulatory target: they show a great deal of variation in their articulatory trajectories and are very sensitive to coarticulation from neighboring segments. [Work supported by NIH Grant Nos. DC-00121 and HD-01994 to Haskins Laboratories.]
Measurements of ocean surface and bottom backscattering strengths in the northwestern Atlantic Ocean
Authors: Davis Nolan R. , Jeffery Joseph , Erskine Fred T.
Published: October 2005

Experimental measurements of ocean surface and bottom backscattering strengths were carried out in the northwestern Atlantic Ocean during July and August of 1990. The experiment used ship-deployed explosive charges to provide ensonification of the ocean surface and bottom over a range of low frequencies up to 1 kHz. Overall the surface scatter results agreed well with the Ogden–Erskine curves, matching the predicted dependence on wind speed, grazing angle, and frequency. At two sites northeast of the Grand Banks the surface scattering strengths appeared to be dominated by volume scattering due to fish. The bottom scattering strengths were observed to have considerable variation in level (up to 16 dB) between different sites. As a function of grazing angle, most of the bottom scattering strength curves paralleled the Mackenzie curve for grazing angles between 20° and 40°. A moderate frequency dependence of less than 3 dB was observed. Comparisons of the bottom scattering strengths with the Damuth 3.5-kHz echo-character province types yielded no consistent correlations. Comparisons with archival results for the same region yielded general agreement within 6 dB. Comparison of the ship-based and airborne techniques showed that they yielded comparable scattering strengths to within 5 dB.
A comparison of error sensor strategies for the active control of duct noise
Authors: Zander Anthony C. , Hansen Colin H.
Published: October 2005

A theoretical comparison of a number of error sensor strategies is undertaken for active control of periodic noise in a hard-walled rectangular duct. Error sensor strategies investigated include the minimization of pressure at a point, the total real acoustic power output, and an estimate of the acoustic potential energy. A new error sensor strategy is also proposed and investigated. The strategy is based upon minimization of the power flow determined by a modal decomposition of the duct sound field. The error sensor strategies are analyzed for both plane-wave and multimode sound fields, and for a range of duct termination conditions. The criterion used to assess the error sensor strategies is the minimization of the sound field downstream of the control sources.
Wave-number spectrum and normal mode solutions for sound scattering from internally loaded cylindrical shells
Authors: Guo Y. P. , Felsen L. B.
Published: October 2005

In a companion paper [L. B. Felsen and Y. P. Guo, J. Acoust. Soc. Am. 94, ⧠⧠ (1993)], two-dimensional acoustic wave scattering from a thin elastic cylindrical shell with internal loading has been expressed in terms of a hybrid ray-mode algorithm that combines ray-type traveling wave fields in the fluid with resonant modes in the structure. The algorithm is based on decomposition of the overall problem into a background problem for the empty shell, on which the internal loads are accounted for by induced equivalent forces at the load attachment points. In the numerical implementation, it was found convenient to express the induced forces due to the internal loading and consequent modal resonances in harmonic series form. This use of the angular harmonics solution for the coupling forces is not only computationally efficient, but also reveals the mechanisms that are responsible for many features observed in the far field. Nevertheless, it is of interest to formulate and solve the problem entirely in a traveling-wave-based representation, which is the counterpoise to the previous solution strategy based entirely on angular harmonics [Y. P. Guo, ‘‘Sound scattering from an internally loaded cylindrical shell,’’ J. Acoust. Soc. Am. 91, 926–938 (1992)]. The traveling wave form isolates individual scattering events and charts the evolution of resonances by successive multiple interactions. Poisson summation is shown to transform one solution into the other, thereby exhibiting for each wave constituent the traveling versus standing wave alternatives.
A new approach for active control of sound transmission through an elastic plate backed by a rectangular cavity
Authors: Koshigoe S. , Gillis J. T. , Falangas E. T.
Published: October 2005

A new technique for controlling noise transmission into a cavity using piezoelectric actuators on an elastic plate is discussed. This study involves construction of a fully coupled acoustics/plate interaction model. This model is used to guide development of a new active noise control method. In real implementation, this approach does not require adaptive signal processing such as the least-mean squares (LMS) method to minimize the acoustic energy in the cavity for control [Pan et al., J. Acoust. Soc. Am. 87, 2098–2108 (1990)]. It shares a similar concept with the plate velocity feedback control. However, the plate velocity feedback control is effective only for the plate controlled modes, whereas the new method is effective for both the plate and cavity controlled modes. A comparison of the simulations using the velocity feedback and the least mean squares method with the new technique will be discussed.
Acoustic impedance of the maternal abdomen
Authors: Wodicka George R. , Lam Alison M. , Bhargava Vinay , Sunkel Daniel
Published: October 2005

Contact sensors to monitor fetal heart, breathing, and movement sounds with increased sensitivity and bandwidth are under development. To understand the inherent acoustical properties of the maternal abdomen and its interaction with these sensors, the driving-point impedance Z(jω) was measured in nine women during their last trimester of pregnancy. An electromechanical shaker with a contact area of 2.85 cm2 produced abdominal vibrations between 10 and 500 Hz, and the resulting force and acceleration were measured. After digitally integrating the acceleration signal to obtain the velocity and removing the massive effects of the coupling between the shaker and the abdomen, Z(jω) was estimated using spectral techniques. The imaginary part of Z(jω) depicted a dominant compliance effect at low frequencies, a resonance at a frequency of 28±16 Hz (mean±s.d.), and a dominant mass effect at higher frequencies. The real part of Z(jω) increased steadily with frequency. A series resistance-mass-compliance (R-M-C) circuit modeled these characteristics of Z(jω) well when R was allowed to exactly mimic the frequency dependence of the real part of Z(jω). Estimated element values of 6.6±2.2×10−3 kg for M, 2.1±1.4×10−3 m/N for C, and roughly 10 Ns/m for R (at resonance) were similar to those estimated for other body tissues such as the thigh but quite different from that of the often-studied chest wall.
Distributed acoustic echo cancellation system with double-talk detector
Authors: Kuo Sen M. , Pan Zhibing
Published: October 2005

The acoustic echo cancellation system using the least-mean-square algorithm is an effective technique to reduce acoustic echoes in a hands-free telephone system. However, very high-order adaptive filters and multiple echo paths have computational and convergence problems. Recently, a new acoustic echo cancellation microphone (AECM) system [S. M. Kuo and Z. Pan, J. Acoust. Soc. Am. 93, 1629–1636 (1993)], which uses two closely spaced directional microphones and a low-order adaptive filter, was proposed to solve these problems. In order to make the AECM system work automatically, a double-talk detector, which is presented in this paper, is required. This detector utilizes the power difference between the system output signal and the microphone output signal. Computer simulations were conducted to demonstrate the effectiveness of the detectors. The complete AECM system was implemented on the TMS320C25, and real-time experiments were conducted in the conference room.
Frequency-dependent sound attenuation in the northeastern Pacific Ocean below 400 Hz
Authors: Morris Gerald B.
Published: October 2005

Signals from SUS explosives were received at four hydrophones suspended in the deep ocean from the Research Platform FLIP. Energy flux densities were determined for approximately 700 of these broadband sources at ranges from 70 to 1250 nmi. The normal approach in determining attenuation is to calculate the transmission loss with no frequency-dependent attenuation as a function of range using a numerical model, subtract the calculated spreading loss and attribute the remaining loss to frequency-dependent attenuation. Because of the large losses due to geometric spreading and small losses from the attenuation together with the strongly range-dependent environment calculating the spreading or transmission loss with high accuracy is difficult. An alternate technique was used. Differences in measured propagation losses at various frequency bands up too 400 Hz were used to calculate relative losses referenced to a band near 50 Hz. Assumptions were then made regarding the functional form of the frequency dependency of these losses and the resulting frequency-dependent attenuation losses determined. The resulting values are consistent with a boric acid relaxation frequency of 1 kHz, but the loss coefficient is lower than those predicted from Thorp’s equation. These results are in agreement with published values determined for higher frequencies from cw acoustic transmissions in the same region. [Work supported by ONR.]
Text normalization and ambiguity resolution in speech synthesis
Authors: Yarowsky David
Published: October 2005

Raw text contains many ambiguities that must be resolved in speech synthesis. Numbers and abbreviations often have different pronunciations in different contexts, as in the phrase ‘‘1240 people at 1240 St. Albans St.’’ The token ‘‘IV’’ is pronounced differently in ‘‘Henry IV,’’ ‘‘Section IV,’’ and ‘‘IV drug.’’ Proper names, acronyms, and words with the same part of speech may also have context-sensitive pronunciations. Previous speech synthesizers have used heuristics or simple defaults to handle these cases. In recent work [Sproat etal., in International Conference on Spoken Language Processing (1992)], statistical decision procedures have been applied to this text normalization process. The talk will describe further developments in this work, using Bayesian discriminators and decision lists based on nearby words, word classes, and type of text as evidence for the selection between pronunciation variants. Examples will include implementations of these algorithms in the AT&T Bell Laboratories TTS synthesizer.
Effects of repetition rate, phase, and sex on the auditory brain-stem response in normal hearing subjects
Authors: Parthasarathy T. K.
Published: October 2005

The effects of click repetition rate and phase on wave I and V latency of the auditory brain-stem response (ABR) were evaluated in ten male and female normal hearing subjects. Clicks were presented monaurally via an insert earphone at 70 dB nHL, using either a condensation (C), a rarefaction (R), or a alternating (Alt) stimuli at two rates, 11.1 and 61.1/s. Females had shorter absolute (V) and interpeak latencies (I–V) than the males. These sex-related latency differences were phase independent. Furthermore, the stimulus phase effect on ABR latencies (I and V) were insignificant. Increasing the repetition rate produced greater wave I and V latency shifts for C and Alt clicks than the R clicks. Results seem to suggest significant rate-phase interaction effects on ABR latencies (I and V). However, the phase-sex and the rate-sex interaction effects on ABR latencies (I and V) were insignificant.
The perfect clarinet reed? Vibrational modes of realistic clarinet reeds
Authors: Casadonte Donald
Published: October 2005

Using results obtained from prior investigations into the biology, chemistry, and physics of the clarinet reed [D. Casadonte, J. Acoust. Soc. Am. 90, 2351(A) (1991)], a realistic computer simulation using the ANSYS finite-element program has been developed. Using this simulation, modal frequencies and shapes were isolated for those modes below 20 000 Hz, as well as stress maps of the reed structure, etc. The simulation is flexible enough to allow for the inclusion of any type of ligature, embouchure, air column pressure spectrum, mouthpiece, and variations in reed material properties and biology during any stage of the life cycle of the reed. This allows for most questions of practical importance in reed science to be examined (including those of historical reed shapes). Specifically, the problem of reed resonance [S. C. Thompson, J. Acoust. Soc. Am. 66, 1299–1307 (1979)] is investigated. It is shown that a good reed is one ‘‘tuned’’ to maximize statistically the power output from the overtones of the air column. This tuning is gradually lost as the reed ages. Finally, the reverse procedure of designing a reed shape and material that will maximize the resonance for a typical clarinet air column is studied.
Basal Anthropoids from Egypt and the Antiquity of Africa's Higher Primate Radiation
Authors: Seiffert Erik R. , Simons Elwyn L. , Clyde William C. , Rossie James B. , Attia Yousry , Bown Thomas M. , Chatrath Prithijit , Mathison Mark E.
Published: October 2005

Early anthropoid evolution in Afro-Arabia is poorly documented, with only a few isolated teeth known from before ∼35 million years ago. Here we describe craniodental remains of the primitive anthropoid
Biretia
from ∼37-million-year-old rocks in Egypt.
Biretia
is unique among early anthropoids in exhibiting evidence for nocturnality, but derived dental features shared with younger parapithecids draw this genus, and possibly >45-million-year-old
Algeripithecus
, into a morphologically and behaviorally diverse parapithecoid clade of great antiquity.
The Origins of Stability
Authors: Gibson Greg
Published: October 2005

Robustness and Evolvability in Living Systems
.
By Andreas Wagner
. Princeton University Press, Princeton, NJ, 2005. 383 pp. $49.50, £32.50. ISBN 0-691-12240-7. Princeton Studies in Complexity.

Writing for researchers and graduate students, the author explores the questions of why organisms are robust despite the countless random mutations per generation and how evolution has shaped such robustness.
Photoreceptor for Curling Behavior in
Peranema trichophorum
and Evolution of Eukaryotic Rhodopsins
Authors: Saranak Jureepan , Foster Kenneth W.
Published: October 2005

When it is gliding, the unicellular euglenoid
Peranema trichophorum
uses activation of the photoreceptor rhodopsin to control the probability of its curling behavior. From the curled state, the cell takes off in a new direction. In a similar manner, archaea such as
Halobacterium
use light activation of bacterio- and sensory rhodopsins to control the probability of reversal of the rotation direction of flagella. Each reversal causes the cell to change its direction. In neither case does the cell track light, as known for the rhodopsin-dependent eukaryotic phototaxis of fungi, green algae, cryptomonads, dinoflagellates, and animal larvae. Rhodopsin was identified in
Peranema
by its native action spectrum (peak at 2.43 eV or 510 nm) and by the shifted spectrum (peak at 3.73 eV or 332 nm) upon replacement of the native chromophore with the retinal analog
n
-hexenal. The in vivo physiological activity of
n
-hexenal incorporated to become a chromophore also demonstrates that charge redistribution of a short asymmetric chromophore is sufficient for receptor activation and that the following isomerization step is probably not required when the rest of the native chromophore is missing. This property seems universal among the Euglenozoa, Plant, and Fungus kingdom rhodopsins. The rhodopsins of animals have yet to be studied in this respect. The photoresponse appears to be mediated by Ca
2+
influx.
Comparative Gene Genealogies Indicate that Two Clonal Lineages ofCryptococcus gattiiin British Columbia ResembleStrains from Other Geographical Areas
Authors: Kidd Sarah E. , Guo Hong , Bartlett Karen H. , Xu Jianping , Kronstad James W.
Published: October 2005

Cryptococcus gattiihas recently emerged as a pathogen of humans and animals in the temperate climate of Vancouver Island, British Columbia (B.C.). The majority (∼95%) of the isolates from the island belong to the VGII molecular type, and the remainder belong to the VGI molecular type. The goals of this study were to compare patterns of molecular variation amongC. gattiiisolates from B.C. with those from different areas of the world and to investigate the population structure using a comparative gene genealogy approach. Our results indicate that theC. gattiipopulation in B.C. comprises at least two divergent lineages, corresponding to previously identified VGI and VGII molecular types. The genealogical analysis of strains suggested a predominantly clonal population structure among B.C. isolates, while there was evidence for sexual recombination between different molecular types on a global scale. We found no geographic pattern of strain relationships, and nucleotide sequence comparisons revealed that genotypes among isolates from B.C. were also present among isolates from other areas of the world, indicating extensive strain dispersal. The nucleotide sequence diversity among isolates from B.C. was similar to that among isolates from other areas of the world.
DNA-Bound Bas1 Recruits Pho2 To Activate
ADE
Genes in
Saccharomyces cerevisiae
Authors: Som Indrani , Mitsch Rebecca N. , Urbanowski Jennifer L. , Rolfes Ronda J.
Published: October 2005

Expression of the genes in the
ADE
regulon of
Saccharomyces cerevisiae
is repressed by the presence of purine bases in the extracellular medium and derepressed when cells are grown in the absence of purines. Derepression requires the transcriptional activators Bas1 and Pho2, as well as the biosynthetic intermediates 5′-phosphoribosyl-4-succinocarboxamide-5-aminoimidazole (SAICAR) and 5′-phosphoribosyl-4-carboxamide- 5-aminoimidazole (AICAR). In this study, we investigated if nuclear localization and binding to promoter DNA by the activators are regulated by purines. Using indirect immunofluorescence, we found that Bas1 is localized to the nucleus under both repressing and derepressing conditions. Importantly, we detected Bas1 bound to promoter DNA under both conditions using chromatin immunoprecipitation assays at several
ADE
promoters (
ADE1
,
ADE2
,
ADE4
, and
ADE5,7
) and
HIS4
. We analyzed the binding of Bas1 to wild-type and mutant sequences of the
ADE5,7
promoters in vivo, and found that Bas1 binds independently to each of its two binding sites. Pho2 was not required for the association of Bas1 with chromosomal DNA, but it was required for an increase in Bas1-immunoprecipitated DNA. The presence of Pho2 at promoters was dependent on Bas1 and occurred only under derepressing conditions when the
ADE
genes are transcribed at elevated levels. We propose a model for regulation of the
ADE
genes in which DNA-bound Bas1 is inactive due to masking of its activation domain and Pho2 binds poorly to promoters when cells have sufficient purine nucleotides. Upon limitation for purines, the SAICAR/AICAR regulatory signal is transmitted to the nucleus to increase Bas1 and Pho2 interaction, recruiting Pho2 to promoters and freeing the activation domains for transactivation.
SUR L'ÉQUATION DE CAUCHY–RIEMANN TANGENTIELLE DANS UNE CALOTTE STRICTEMENT PSEUDOCONVEXE
Authors: LAURENT-THIÉBAUT CHRISTINE
Published: October 2005

We search a cohomological and a geometrical characterization of the open subsets of a strictly pseudoconvex boundary in a Stein manifold on which one can solve the tangential Cauchy–Riemann equation in all bidegrees.

On cherche une caractérisation cohomologique et géométrique des ouverts du bord d'un domaine strictement pseudoconvexe relativement compact d'une variété de Stein sur lesquels on peut résoudre l'équation de Cauchy–Riemann tangentielle en tout bidegré.
NOVEL MOTT-INSULATOR PHASES AND QUANTUM CRITICAL POINTS IN OPTICAL LATTICES
Authors: HAN FUXIANG , ZHANG YONGMEI
Published: October 2005

A self-consistent equation is derived for the order parameter of quantum phases in an optical lattice within a mean-field approximation to the Bose–Hubbard model. Analyzing the solutions of the self-consistent equation in terms of the number fluctuations of quasiparticles, the one-body density matrix of atoms, and the normalized correlation function of quasiparticles, we have identified two types of Mott-insulator phases that are characterized by different values of the order parameter, quasiparticle fluctuations, and correlations. We have also identified the quantum critical points separating these two types of Mott-insulator phases and the corresponding quantum critical lines on the phase diagram.
INTUITION OF FAMILY ENTREPRENEURS: AN EXPLORATORY STUDY OF PERCEPTIONS AND EXPERIENCES
Authors: KAKKONEN MARJA-LIISA
Published: October 2005

Many business problems do not appear in ideal conditions. Sometimes decisions have to be made very quickly, or there is no explicit knowledge regarding a problem, or there is neither enough time nor enough information. Therefore, entrepreneurs are not always equipped to make the necessary decision or to solve the problem. A successful entrepreneur needs to rely more often on intuition in making decisions and in solving problems. Intuition can be considered, for example, as a sudden awareness of knowledge. Using this type of knowledge, a person knows facts or relations, but without knowing why.

Previous studies have described the nature of intuition and they have also addressed the intuitive abilities of managers, but the actual use of intuition remains a relatively unchartered research area, as well as the intuition of entrepreneurs. The study reported here is an attempt to broaden our understanding of the intuition of family entrepreneurs. The purpose was to explore through interviews what family entrepreneurs understood by intuition and to establish what kinds of situational factors were involved in experiencing and applying intuition.
STATIONARY SOLUTIONS OF STOCHASTIC DIFFERENTIAL EQUATIONS WITH MEMORY AND STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS
Authors: BAKHTIN YURI , MATTINGLY JONATHAN C.
Published: October 2005

We explore Itô stochastic differential equations where the drift term possibly depends on the infinite past. Assuming the existence of a Lyapunov function, we prove the existence of a stationary solution assuming only minimal continuity of the coefficients. Uniqueness of the stationary solution is proven if the dependence on the past decays sufficiently fast. The results of this paper are then applied to stochastically forced dissipative partial differential equations such as the stochastic Navier–Stokes equation and stochastic Ginsburg–Landau equation.
DIFFERENTIAL EQUATIONS, DUALITY AND MODULAR INVARIANCE
Authors: HUANG YI-ZHI
Published: October 2005

We solve the problem of constructing all chiral genus-one correlation functions from chiral genus-zero correlation functions associated to a vertex operator algebra satisfying the following conditions: (i) V(n) = 0 for n < 0 and V(0) = ℂ1, (ii) every ℕ-gradable weak V-module is completely reducible and (iii) V is C2-cofinite. We establish the fundamental properties of these functions, including suitably formulated commutativity, associativity and modular invariance. The method we develop and use here is completely different from the one previously used by Zhu and others. In particular, we show that the q-traces of products of certain geometrically-modified intertwining operators satisfy modular invariant systems of differential equations which, for any fixed modular parameter, reduce to doubly-periodic systems with only regular singular points. Together with the results obtained by the author in the genus-zero case, the results of the present paper solves essentially the problem of constructing chiral genus-one weakly conformal field theories from the representations of a vertex operator algebra satisfying the conditions above.
Is insulin an anabolic agent in bone? Dissecting the diabetic bone for clues
Authors: Thrailkill Kathryn M. , Lumpkin Charles K. , Bunn R. Clay , Kemp Stephen F. , Fowlkes John L.
Published: October 2005

Diabetic osteoporosis is increasingly recognized as a significant comorbidity of type 1 diabetes mellitus. In contrast, type 2 diabetes mellitus is more commonly associated with modest increases in bone mineral density for age. Despite this dichotomy, clinical, in vivo, and in vitro data uniformly support the concept that new bone formation as well as bone microarchitectural integrity are altered in the diabetic state, leading to an increased risk for fragility fracture and inadequate bone regeneration following injury. In this review, we examine the contribution that insulin, as a potential anabolic agent in bone, may make to the pathophysiology of diabetic bone disease. Specifically, we have assimilated human and animal data examining the effects of endogenous insulin production, exogenous insulin administration, insulin sensitivity, and insulin signaling on bone. In so doing, we present evidence that insulin, acting as an anabolic agent in bone, can preserve and increase bone density and bone strength, presumably through direct and/or indirect effects on bone formation.
Adaptor heat shock protein complex formation regulates trafficking of the asialoglycoprotein receptor
Authors: Huang Tianmin , Wolkoff Allan W. , Stockert Richard J.
Published: October 2005

In the asialoglycoprotein receptor (ASGPR) endocytic pathway, internalized receptors pass through early, recycling, and sorting endosomal compartments before returning to the cell surface. Sorting motifs in the cytoplasmic domain (CD) and protein interactions with these sequences presumably direct receptor trafficking. Previous studies have shown that association of a potential sorting heat shock protein (HSP) heterocomplex with the ASGPR-CD was regulated by casein kinase 2 (CK2)-mediated phosphorylation. Mass spectrometry and immunoblot analyses identified five of these ASGPR-CD-associated proteins as the molecular chaperones glycoprotein 96, HSP70, HSP90, cyclophilin A, and FK 506 binding protein. The present study was undertaken to determine whether any of the adaptor protein complexes (AP1, AP2, or AP3) were selectivity associated with the ASGPR-CD. In conjunction with molecular chaperones, AP2 and AP1 were recovered from a CK2 phosphorylated agarose-GSH-GST-ASGPR-CD matrix. Binding of AP3 was independent of the phosphorylation status of the CD matrix. Inhibition of CK2-mediated phosphorylation with tetrabromobenzotriazole prevented AP recovery within an immunoadsorbed ASGPR complex. Rapamycin, which dissociates the HSP heterocomplex from ASGPR-CD, thereby altering receptor trafficking also, inhibited AP association. Similar results were obtained with an inhibitor of HSP90 heterocomplex formation, geldanmycin. The data presented provide evidence that recruitment of AP1 and AP2, which is necessary for appropriate receptor trafficking, is mediated by the interaction of AP with the ASGPR-CD-bound HSP complex.
Mechanism of ACh-induced asynchronous calcium waves and tonic contraction in porcine tracheal muscle bundle
Authors: Dai Jiazhen M. , Kuo Kuo-Hsing , Leo Joyce M. , van Breemen Cornelis , Lee Cheng-Han
Published: October 2005

Stimulation of the tracheal muscle bundle by acetylcholine (ACh) results in the generation of asynchronous repetitive Ca2+ waves (ACW) in intact tracheal smooth muscle (TSM) cells. We showed previously that ACW underlie cholinergic excitation-contraction coupling in porcine TSM and that Ca2+ entry through the L-type voltage-gated Ca2+ channel (VGCC) contributes partially to maintenance of the ACW. However, the mechanism of the ACW remains undefined. In this study, we pharmacologically characterized the mechanism of ACh-induced ACW in the intact porcine tracheal muscle bundle. We found that inhibition of receptor-operated channels/store-operated channels (ROC/SOC) by SKF-96365 completely abolished the nifedipine-insensitive component of ACh-mediated ACW and tonic contraction. Blockade of Na+/Ca2+ exchange with KB-R7943 or 2′,4′-dichlorobenzamil or removal of extracellular Na+ resulted in nearly complete inhibition of the nifedipine-insensitive component of ACh-mediated ACW and tonic contraction. Inhibition of the sarco(endo)plasmic reticulum Ca2+-ATPase by cyclopiazonic acid abolished the ongoing ACW. Application of 2-aminoethoxydiphenyl borate (2-APB) or xestospongin C to inhibit the inositol 1,4,5-trisphosphate-sensitive sarcoplasmic reticulum (SR) Ca2+ release channels produced no effect on ACh-mediated ACW and tonic contraction. However, pretreatment with caffeine or ryanodine inhibited ACh-induced ACW. Furthermore, application of procaine or tetracaine prevented the generation and abolished the ongoing ACh-mediated ACW and tonic contraction. Collectively, these results indicate that the ACh-stimulated ACW in porcine TSM are produced by repetitive cycles of Ca2+ release from SR through 2-APB- and xestospongin C-insensitive Ca2+ release channels, and plasmalemmal Ca2+ entry involving reverse-mode Na+/Ca2+ exchange, ROC/SOC, and L-type VGCC is required to refill the SR via SERCA to support the ongoing ACW.
Social isolation and the inflammatory response: sex differences in the enduring effects of a prior stressor
Authors: Hermes Gretchen L. , Rosenthal Louis , Montag Anthony , McClintock Martha K.
Published: October 2005

Numerous epidemiological studies have demonstrated an association between persistent social isolation and “all-cause” morbidity and mortality. To date, no causal mechanism for these findings has been established. Whereas animal studies have often reported short-term effects of social isolation on biological systems, the long-term effects of this adverse psychological state have been understudied. This is the first animal study to examine the effects of long-term social isolation from weaning through young adulthood on an innate inflammatory response linked to numerous disease processes. Results presented here offer a plausible link between vulnerability to disease and social neglect. For socially isolated male and female Sprague-Dawley rats, a naturally gregarious species, formation of a granuloma in response to a subcutaneous injection of carrageenin (seaweed) was significantly delayed compared with the response of animals housed in single-sex groups of five. Significant sex differences, however, emerged when an acute prior stressor was superimposed on the experience of chronic social isolation. In this context, isolated females produced a more robust inflammatory response than isolated males. This sexual dimorphism at the nexus of chronic social isolation, acute stress, and inflammatory processes may account for the observation in humans that men with low levels of social integration are more vulnerable to disease and death than women.
Rehydration with glycerol: endocrine, cardiovascular, and thermoregulatory responses during exercise in the heat
Authors: Kavouras Stavros A. , Armstrong Lawrence E. , Maresh Carl M. , Casa Douglas J. , Herrera-Soto Jorge A. , Scheett Timothy P. , Stoppani James , Mack Gary W. , Kraemer William J.
Published: October 2005

The impact of rehydration with glycerol on cardiovascular and thermoregulatory responses during exercise in the heat was studied in eight highly trained male cyclists. Each subject completed three dehydration-rehydration experimental trials that differed only in the rehydration treatment, each separated by 7 days. Before each experimental day, subjects dehydrated to −4% of their body weight by exercise and water restriction. The experimental treatments were as follows: no fluid (NF), glycerol bolus (1 g/kg body wt) followed by water (G), and water alone (W). Rehydration (3% body weight) was given over an 80-min period. After rehydration, subjects cycled (74% peak O2 uptake) to exhaustion in a hot and wet (37°C and 48% relative humidity) environment. For G, plasma volume was expanded ( P < 0.05) during rehydration and remained higher than W ( P < 0.05) during exercise. Exercise time to exhaustion during G (33 ± 4 min) was longer ( P < 0.05) compared with both W (27 ± 3 min) and NF (19 ± 3 min). Cutaneous vascular conductance was significantly elevated ( P < 0.05) during G, but G provided no other thermoregulatory or cardiovascular benefits compared with W and NF. Fluid-regulating hormones (vasopressin, aldosterone, atriopeptin, and plasma renin activity) decreased during rehydration and increased during exercise (except atriopeptin), but there were no differences between G and W. These data indicated that glycerol had little or no major effect on fluid-regulating factors during rehydration or exercise, and the improved exercise capacity in G was likely due to a greater plasma volume during exercise.
Surfactant replacement partially restores the activity of pulmonary stretch receptors in surfactant-depleted cats
Authors: Sindelar Richard , Jonzon Anders , Schulze Andreas , Sedin Gunnar
Published: October 2005

Single units of slowly adapting pulmonary stretch receptors (PSRs) were investigated in anesthetized cats during spontaneous breathing on continuous positive airway pressure (2–5 cmH2O), before and after lung lavage and then after instillation of surfactant to determine the PSR response to surfactant replacement. PSRs were classified as high threshold (HT) and low threshold (LT), and their instantaneous impulse frequency ( fimp) was related to transpulmonary pressure (Ptp) and tidal volume (Vt). Both the total number of impulses and maximal fimpof HT and LT PSRs decreased after lung lavage (55 and 45%, respectively) in the presence of increased Ptp and decreased Vt. While Ptp decreased markedly and Vt remained unchanged after surfactant instillation, all except one PSR responded with increased total number of impulses and maximal fimp(42 and 26%, respectively). Some HT PSRs ceased to discharge after lung lavage but recovered after surfactant instillation. The end-expiratory activity of LT PSRs increased or was regained after surfactant instillation. After instillation of surfactant, respiratory rate increased further with a shorter inspiratory time, resulting in a lower inspiratory-to-expiratory time ratio. Arterial pH decreased (7.31 ± 0.04 vs. 7.22 ± 0.06) and Pco2increased (5.5 ± 0.7 vs. 7.2 ± 1.3 kPa) after lung lavage, but they were the same after as before instillation of surfactant (pH = 7.21 ± 0.08 and Pco2= 7.6 ± 1.4 kPa) during spontaneous breathing. In conclusion, surfactant instillation increased lung compliance, which, in turn, increased the activity of both HT and LT PSRs. A further increase in respiratory rate due to a shorter inspiratory time after surfactant instillation suggests that the partially restored PSR activity after surfactant instillation affected the breathing pattern.