bluuebunny/crossref_metadata_2025 huggingface dataset:
A peripheral mechanism for auditory directionality in the bushcricket Gampsocleis gratiosa: Acoustic tracheal system
Authors: Shen Jun-Xian
Published: October 2005

The hypothesis that the acoustic tracheal system is a peripheral mechanism for auditory directionality was tested in the bushcricket Gampsocleis gratiosa. The acoustic tracheal system comprises the large spiracle, vesicle, and long tapering trachea. Based on its anatomy and cross-sectional areas against axial distance, an acoustic model was proposed; this model is analogous to an exponential horn with a flaring constant of about 0.075 mm−1. The effects of the acoustic tracheal system on auditory threshold and directionality were measured by using an electrophysiological recording from single auditory neurons. The intact tracheal system was found to be essential for directional hearing. Blockage of the spiracle markedly influenced the auditory threshold and directionality of the ipsilateral auditory neurons, but had very little effect on contralateral auditory neurons. The effects of blockage of the ipsilateral spiracle on auditory thresholds were frequency dependent with a gain of about 15–40 dB over a frequency range of 7–30 kHz. The directional threshold differences were measured for single auditory neurons. Blockage of the ipsilateral spiracle abolished directional sensitivity of these neurons. But blockage of the tympanal slits had less effect on directional sensitivity of this tettigoniid species, with a decrement of about 1 to 3 dB.
Effects of spectral smearing on the intelligibility of sentences in noise
Authors: Baer Thomas , Moore Brian C. J.
Published: October 2005

Cochlear hearing loss is generally associated with a variety of deficits in the ability to analyze sounds, including reduced frequency selectivity. The complex interrelationships between the different deficits have made it difficult to assess the contribution of reduced frequency selectivity to the difficulties experienced by hearing-impaired people in understanding speech. To address this question, the effects of reduced frequency selectivity on the place representation of speech stimuli in the auditory system were simulated by ‘‘smearing’’ the spectra of the stimuli, using the overlap–add method. The smearing was designed to evoke excitation patterns in a normal ear that would resemble those evoked in an impaired ear using unsmeared stimuli. Several different types of smearing were used, simulating specific degrees of broadening and asymmetry of the auditory filter. Sentences in quiet and in speech-shaped noise were smeared and presented to normally hearing listeners in intelligibility tests. The results showed that the intelligibility of speech in quiet was hardly affected by spectral smearing, even for smearing that simulated auditory filters six times broader than normal. However, the intelligibility of speech in noise was adversely affected by the smearing, especially for large degrees of smearing and at a low speech-to-noise ratio (−3 dB). Simulation of asymmetrical broadening of the lower side of the auditory filter had a greater effect than simulation of asymmetrical broadening of the upper side, suggesting that upward spread of masking may be particularly important.
A cross-linguistic investigation of locus equations as a phonetic descriptor for place of articulation
Authors: Sussman Harvey M. , Hoemeke Kathryn A. , Ahmed Farhan S.
Published: October 2005

A previous study [H. Sussman, H. McCaffrey, and S. Matthews, J. Acoust. Soc. Am. 90, 1309–1325 (1991)] of American English CV coarticulation showed a remarkably linear relationship between onset frequencies of F2 transitions, plotted on the y axis, in relation to the F2 midvowel ‘‘target’’ frequencies, plotted on the x axis, for CVC tokens with initial [b d g] and ten medial vowel contexts. Slope and y-intercept values of regression functions fit to these scatterplots (‘‘locus equations’’) were shown to serve as statistically powerful phonetic descriptors of place of articulation. The present study extends the locus equation metric to three additional languages—Thai, Cairene Arabic, and Urdu—having both two and four place contrasts for syllable-initial voiced stops. A total of 14 speakers (Thai=6, Arabic=3, Urdu=5) produced 1740 CVC tokens that were acoustically analyzed using MacSpeech Lab II. Strong linear regression relationships were found for every stop category across all speakers. Slopes and y intercepts systematically varied as a function of place of articulation. Cross-language comparisons of stop place categories were performed but variability of slope and y intercept means tempered conclusions concerning the existence of CV ‘‘phonetic hot spots.’’
Development of a directional hearing instrument based on array technology
Authors: Soede Wim , Berkhout Augustinus J. , Bilsen Frans A.
Published: October 2005

A directional hearing aid might be beneficial in reducing background noise in relation to the desired speech signal. Conventional hearing aids with a directional cardioid microphone are insufficient because of the low directivity of cardioids. Research was done to develop microphone(s) with strong directional characteristics using array techniques. Particular emphasis was given to optimization and stability. Free-field simulations of several robust models show that a directivity index of 9 dB can be obtained at the higher frequencies. Simulations were verified with a laboratory model. The results of the measurements show a good agreement with the simulations. Based on simulations and measurements, two portable models were developed and tested with a KEMAR manikin. The KEMAR measurements show that the two models give an improvement of the signal-to-noise ratio of approximately 7.5 dB in a diffuse sound field. It may be concluded that the developed microphones have the capability to reach a significant improvement of speech intelligibility in noise under practical circumstances.
Assessment of a directional microphone array for hearing-impaired listeners
Authors: Soede Wim , Bilsen Frans A. , Berkhout Augustinus J.
Published: October 2005

Hearing-impaired listeners often have great difficulty understanding speech in surroundings with background noise or reverberation. Based on array techniques, two microphone prototypes (broadside and endfire) have been developed with strongly directional characteristics [Soede et al., ‘‘Development of a new directional hearing instrument based on array technology,’’ J. Acoust. Soc. Am. 94, (1993)]. Physical measurements show that the arrays attenuate reverberant sound by 6 dB (free-field) and can improve the signal-to-noise ratio by 7 dB in a diffuse noise field (measured with a KEMAR manikin). For the clinical assessment of these microphones an experimental setup was made in a sound-insulated listening room with one loudspeaker in front of the listener simulating the partner in a discussion and eight loudspeakers placed on the edges of a cube producing a diffuse background noise. The hearing-impaired subject wearing his own (familiar) hearing aid is placed in the center of the cube. The speech-reception threshold in noise for simple Dutch sentences was determined with a normal single omnidirectional microphone and with one of the microphone arrays. The results of monaural listening tests with hearing impaired subjects show that in comparison with an omnidirectional hearing-aid microphone the broadside and endfire microphone array gives a mean improvement of the speech reception threshold in noise of 7.0 dB (26 subjects) and 6.8 dB (27 subjects), respectively. Binaural listening with two endfire microphone arrays gives a binaural improvement which is comparable to the binaural improvement obtained by listening with two normal ears or two conventional hearing aids.
A model and numerical method in the medium frequency range for vibroacoustic predictions using the theory of structural fuzzy
Authors: Soize Christian
Published: October 2005

In linear dynamical analysis of complex mechanical systems, the structural fuzzy is defined as the set of minor subsystems that are connected to the master structure but are not accessible by classical modeling. The notion of master structure is presently extended to others elements such as an external dense compressible fluid strongly coupled with the primary structure. For the low-frequency (LF) dynamical analysis, the modeling of the structural fuzzy is commonly made with a system of masses. If the LF modeling of the structural fuzzy is applied in the medium-frequency (MF) domain, there are some large differences between calculations and experiment. It is therefore necessary to take into account internal degrees of freedom of the structural fuzzy. A global probabilistic modeling of the structural fuzzy is proposed to improve the calculated estimates of the MF vibrations into the master structure and of the far field radiated by itself in or out of context of the acoustic scattering. This paper reviews the author’s previous work and introduces the type II probabilistic constitutive law. In this paper: (1) a probabilistic modeling of the structural fuzzy is presented, (2) two probabilistic constitutive laws of the structural fuzzy are constructed, (3) the modeling in the MF range for vibroacoustic predictions using theory of structural fuzzy is developed, (4) the fuzzy solution in the MF range is studied, and (5) numerical simulations on standard structures and on a submerged complex industrial structure are shown.
Structural acoustic response of finite rib-reinforced plates
Authors: Keltie Richard F.
Published: October 2005

The structural acoustic response of finite fluid-loaded flat plates with arbitrary attached rib stiffeners was formulated. The ribs were modeled as simple inertial reactions providing transverse forces to the plate structure. The plate response and the surface acoustic pressure distribution were written as expansions in terms of the in vacuo plate eigenfunctions. The expansion coefficients were obtained by solving a set of simultaneous complex linear algebraic equations. Results were obtained for an unribbed steel plate, and for a steel plate with a set of uniform ribs, in response to harmonic line-force excitation. The results demonstrated the potential for significant reductions in the vibration level by approximately 90% at certain frequencies because of the presence of the attached ribs. These reductions were attributed to the interaction of two nearly resonant modes in a ‘‘beating’’ phenomenon. It was shown that this ‘‘beating’’ arises because of the presence of the ribs. In order to quantify this effect, a quantity called the ‘‘rib function’’ was defined and was shown to be dependent upon the rib masses, their locations, and the in vacuo mode shapes.
An energy-conserving parabolic equation for elastic media
Authors: Collins Michael D.
Published: October 2005

The accuracy of the parabolic equation (PE) method is improved for range-dependent elastic media. The energy-conserving elastic PE is a generalization of the energy-conserving acoustic PE. A range-dependent waveguide is approximated by a sequence of range-independent regions. A linear approximation is derived for the nonlinear condition corresponding to conservation of compressional energy flux at the vertical interfaces between range-independent regions. The rotated elastic PE is applied to generate reference solutions for demonstrating accuracy. The energy-conserving elastic PE is applied to solve problems involving the propagation of an interface wave along a sloping ocean bottom and a problem involving mode cutoff and coupling into shear wave beams in the ocean bottom. The latter problem is analogous to a cutoff problem that was first solved with the acoustic PE [F. B. Jensen and W. A. Kuperman, J. Acoust. Soc. Am. 67, 1564–1566 (1980)].
Attending to auditory filters that were not stimulated directlya)
Authors: Hafter Ervin R. , Schlauch Robert S. , Tang Joyce
Published: October 2005

The effectiveness of two types of tonal cues for reducing frequency uncertainty was studied in a tonal detection-in-noise task. Signals varied at random from trial to trial over the range 750–3000 Hz. The three conditions included: (1) maximum uncertainty in which there were no cues; (2) minimal uncertainty in which ‘‘iconic cues’’ were identical to the signal to be detected; and (3) partial uncertainty in which ‘‘relative cues’’ were set to 2/3 of the signal frequency, i.e., at the musical 5th. Results show that relative cues and iconic cues were both effective in reducing uncertainty compared to the no-cue condition, but that performance with relative cues was poorer than with iconic cues by 1.4 dB. In addition, a modified probe-signal method was used to estimate the widths of the subjective listening bands. Application of a model of the auditory filter [R. Patterson and B. C. J. Moore, Frequency Selectivity in Hearing, edited by B. C. J. Moore (Academic, New York, 1986)] to these data showed that the subjective listening bands used with iconic cues were similar in width to typical measures of the critical band but that the bands used with relative cues were wider by a factor of roughly 1.6.
Demonstration of the precedence effect in an insect
Authors: Wyttenbach Robert A. , Hoy Ronald R.
Published: October 2005

Field crickets are interesting models for study of auditory phenomena because they solve many of the same acoustic problems as humans, but with simpler nervous systems. Previous work in this lab and others has investigated sound localization, frequency and temporal pattern discrimination, habituation and dishabituation, and categorical perception. This paper demonstrates the precedence effect in crickets, using a standard two-pulse paradigm with a directional escape response to ultrasound. When two pulses of ultrasound are presented from opposite sides with a delay between, crickets respond only to the first pulse for delays of approximately 4 to 75 ms. For delays of 0 to 2 ms, the direction of response is variable (the first wave front does not have precedence); for delays over approximately 75 ms, crickets respond directionally to each of the two pulses. Some neural correlates of the precedence effect were studied by using this paradigm during recordings from a bilateral pair of ascending second-order auditory interneurons known to initiate ultrasound avoidance. There are no ipsilateral–contralateral differences in their responses that could account for the precedence effect; such interactions in the brain must be involved instead. This seems to be the first test of precedence effect in a nonmammal.
Adaptation of suppression as an explanation of enhancement effectsa)
Authors: Wright Beverly A. , McFadden Dennis , Champlin Craig A.
Published: October 2005

Delaying the onset of a signal relative to the onset of a simultaneous notched masker often improves the ability of subjects to ‘‘hear out’’ the signal at both threshold and suprathreshold levels. Viemeister and Bacon [J. Acoust. Soc. Am. 71, 1502–1507 (1982)] suggested that such signal-enhancement effects might be attributable to adaptation of the suppression directed from the masker to the signal, thereby releasing the signal from suppression. In support of their hypothesis, Viemeister and Bacon reported that a masker, preceded by an enhancer having no component at the signal frequency, produced more forward masking than did the masker by itself. Here the masker enhancement described by Viemeister and Bacon, signal enhancement, and two-tone suppression were measured in the same six subjects. Parametric manipulations of the masker-enhancement stimulus produced results similar to those previously reported for parallel investigations of signal enhancement, indicating that the two types of enhancement are closely related effects. Although the present data reveal an inverse relationship between the amounts of suppression and enhancement, suggesting that the two processes may be interrelated, no support was obtained for the hypothesis that adaptation of suppression can account for enhancement.
Pitch center of musical sounds with vibrato
Authors: Brown Judith C. , Vaughn Kathryn
Published: October 2005

The determination of the pitch center of sounds that are frequency modulated has been the focus of a number of previous studies. The sources have usually been pure tones or synthetic complex sounds with a well-defined spectral composition. In a musical context these synthetic sounds differ in temporal and spectral properties from the natural sounds produced by stringed instruments; and it is these natural sounds which performers are trained to produce and to perceive in order to make intonation choices. Samples consisting of approximately 1 s of acoustic sounds produced by a virtuoso violist playing the notes D4, C5♯, A5, and G6 with and without vibrato have been chosen for this study. The sounds without vibrato were then resampled to give frequencies from −15 to +21 cents, with respect to the geometric center of the sound, with vibrato. Experiments with forced choice for pairs of sounds using musically experienced listeners (including the violist who produced the original sounds) as subjects will be reported. These experiments include a control set consisting of the comparison of pitch levels of these same sounds played without vibrato. Preliminary results with listeners who are not string players are in accord with previous results, finding that the pitch perceived is that of the geometric average.
Introductory acoustics laboratory experiments
Authors: Hansen Uwe J.
Published: October 2005

A course on musical acoustics designed for music majors with little or no background in science serves a number of purposes. Among these is the intent to give insight into the structure of musical sound and the physical nature of various musical instruments, and to enhance the scientific literacy of music students. Meeting these objectives is enhanced significantly if students have the opportunity to learn with their hands and ears. A series of four introductory experiments will be described and illustrated. These are (1) measuring frequency with an oscilloscope, (2) complex wave synthesis with a simple keyboard, (3) the spectrum of an elastic string, (4) the inharmonic spectrum of a stiff string.
Capillary wave turbulence
Authors: Wright William , Budak Raffi , Putterman Seth J.
Published: October 2005

The transition from a discrete spectrum of higher harmonics to a broadband power spectrum has been observed with a wire probe (as regards the frequency spectrum) and imaging of the surface (as regards the wave-number spectrum). By use of laser scattering techniques we hope to obtain an absolute calibration of the surface motion in this very far-off equilibrium state. [Work supported by the U.S. DOE Division of Engineering and Geophysics and by NASA.]
Relation between waveguide and nonwaveguide (half-space) scattering from a rough interface
Authors: Gao T. F. , Shang E. C.
Published: October 2005

A formal solution of the scattering field from a rough interface has been derived. Under the Bass perturbation theory, both waveguide and nonwaveguide (half-space) scattering from a rough interface (the sea bottom) can be calculated analytically. By using an identical definition of ‘‘scattering coefficient,’’ a relation between the waveguide scattering (the modal S matrix) Mljs and the nonwaveguide scattering (conventional plane-wave scattering) coefficient ms has been found: Mljs= (2π)2ms/‖V(θl)V(θj)‖, where V(θl) and V(θj) represent the reflection coefficients of the plane interface for the modal incident angles θl and θj, respectively. Consequently, based on this relation, the ms data measured in the conventional sense (half-space) can be bridged into a shallow water reverberation prediction or vice versa.
Photonic band gaps in periodic elastic composites 2-D hexagonal lattices
Authors: Kushwaha M. S. , Halevi P.
Published: October 2005

The acoustic band structure of periodic elastic composites were calculated using position-dependent density and elastic constant. The specific system investigated is made up of a periodic array of parallel metallic rods of circular cross section whose intersections with a perpendicular plane from a hexagonal lattice. The rods are embedded in a background medium with different elastic constant and density. The transverse polarization was considered—with displacement u(r,t) parallel to the cylinders (and perpendicular to the Bloch wave vectors). The absolute band gaps extending throughout the first Brillouin zone were found in the low-frequency regime. The specific case studied was Cu(Al) cylinders in the Al(Cu) background. A direct comparison of the hexagonal case with the square-lattice pattern (Kushwaha etal., preceding abstract in this session) reveals that the widths of these band gaps are larger in the case of hexagonal lattices. The precise dependence of the gaps on the filling fraction is investigated.
Acoustic reciprocity for fluid-structure problems
Authors: Norris Andrew N. , Rebinsky Douglas A.
Published: October 2005

A reciprocity relation for acoustic interaction with fluid-loaded structures is derived. The displacement in the direction e(2) at any position x(2) in the solid due to a monopole of strength (ρfω2) at any position x(1) in the fluid is equal to the pressure at x(1) caused by a unit force in the direction e(2) applied at x(2). An application to plane wave scattering is discussed.
Precision measurement of acoustic velocities in pure gases and gas mixtures
Authors: Giacobbe F. W.
Published: October 2005

A specialized cylindrical acoustic resonator has been designed and fabricated to measure absolute sound speeds in pure gases and gas mixtures. This device was used to make experimental sound-speed measurements in air, argon, carbon dioxide, helium, hydrogen, methane, neon, nitrogen, nitrous oxide, and oxygen near ambient temperatures. Initially determined sound speeds were then corrected to account for the influences of temperature, viscosity, and thermal conductivity within the cylindrical resonator. The resulting corrected (unconfined) values, at 0.0 and 25.0 °C, were tabulated and compared with earlier experimentally measured values. The apparatus and methods employed to produce and correct this laboratory data were also described in detail. It was shown that mean acoustic velocities could be resolved (using the apparatus and techniques described in this paper) with uncertainties of approximately ±0.15% from only three separate sets of experimental test trials per gas tested. In addition, repeated determinations of the acoustic velocities in dry, carbon dioxide free, air indicated that uncertainties of less than ±0.1% could be achieved in average acoustic velocities obtained from ten or more independent sets of test trials.
Extrasolar Planets: Constraints for Planet Formation Models
Authors: Santos Nuno C. , Benz Willy , Mayor Michel
Published: October 2005

Since 1995, more than 150 extrasolar planets have been discovered, most of them in orbits quite different from those of the giant planets in our own solar system. The number of discovered extrasolar planets demonstrates that planetary systems are common but also that they may possess a large variety of properties. As the number of detections grows, statistical studies of the properties of exoplanets and their host stars can be conducted to unravel some of the key physical and chemical processes leading to the formation of planetary systems.
Counting Cytokinesis Proteins Globally and Locally in Fission Yeast
Authors: Wu Jian-Qiu , Pollard Thomas D.
Published: October 2005

We used fluorescence microscopy to measure global and local concentrations of 28 cytoskeletal and signaling proteins fused to yellow fluorescent protein (YFP) in the fission yeast
Schizosaccharomyces pombe
. Native promoters controlled the expression of these functional YFP fusion proteins. Fluorescence measured by microscopy or flow cytometry was directly proportional to protein concentration measured by quantitative immunoblotting. Global cytoplasmic concentrations ranged from 0.04 (formin Cdc12p) to 63 micromolar (actin). Proteins concentrated up to 100 times in contractile rings and 7500 times in spindle pole bodies at certain times in the cell cycle. This approach can be used to measure the global and local concentrations of any fusion protein.
Observing Others: Multiple Action Representation in the Frontal Lobe
Authors: Nelissen Koen , Luppino Giuseppe , Vanduffel Wim , Rizzolatti Giacomo , Orban Guy A
Published: October 2005

Observation of actions performed by others activates monkey ventral premotor cortex, where action meaning, but not object identity, is coded. In a functional MRI (fMRI) study, we investigated whether other monkey frontal areas respond to actions performed by others. Observation of a hand grasping objects activated four frontal areas: rostral F5 and areas 45B, 45A, and 46. Observation of an individual grasping an object also activated caudal F5, which indicates different degrees of action abstraction in F5. Observation of shapes activated area 45, but not premotor F5. Convergence of object and action information in area 45 may be important for full comprehension of actions.
The Promotional Effect of Gold in Catalysis by Palladium-Gold
Authors: Chen Mingshu , Kumar Dheeraj , Yi Cheol-Woo , Goodman D. Wayne
Published: October 2005

Acetoxylation of ethylene to vinyl acetate (VA) was used to investigate the mechanism of the promotional effect of gold (Au) in a palladium (Pd)-Au alloy catalyst. The enhanced rates of VA formation for low Pd coverages relative to high Pd coverages on Au single-crystal surfaces demonstrate that the critical reaction site for VA synthesis consists of two noncontiguous, suitably spaced, Pd monomers. The role of Au is to isolate single Pd sites that facilitate the coupling of critical surface species to product, while inhibiting the formation of undesirable reaction by-products.
A Secondary Symbiosis in Progress?
Authors: Okamoto Noriko , Inouye Isao
Published: October 2005

Algae have acquired plastids by developing an endosymbiotic relationship with either a cyanobacterium (primary endosymbiosis) or other eukaryotic algae (secondary endosymbiosis). We report a protist, which we tentatively refer to as Hatena, that hosts an endosymbiotic green algal partner but inherits it unevenly. The endosymbiosis causes drastic morphological changes to both the symbiont and the host cell architecture. This type of life cycle, in which endosymbiont integration has only partially converted the host from predator to autotroph, may represent an early stage of plastid acquisition through secondary symbiosis.
Selection on Heritable Phenotypic Plasticity in a Wild Bird Population
Authors: Nussey Daniel H. , Postma Erik , Gienapp Phillip , Visser Marcel E.
Published: October 2005

Theoretical and laboratory research suggests that phenotypic plasticity can evolve under selection. However, evidence for its evolutionary potential from the wild is lacking. We present evidence from a Dutch population of great tits (
Parus major
) for variation in individual plasticity in the timing of reproduction, and we show that this variation is heritable. Selection favoring highly plastic individuals has intensified over a 32-year period. This temporal trend is concurrent with climate change causing a mismatch between the breeding times of the birds and their caterpillar prey. Continued selection on plasticity can act to alleviate this mismatch.
Shocks in Ion Sputtering Sharpen Steep Surface Features
Authors: Chen H. Henry , Urquidez Omar A. , Ichim Stefan , Rodriquez L. Humberto , Brenner Michael P. , Aziz Michael J.
Published: October 2005

We report a regime of ion beam sputtering that occurs for sufficiently steep slopes. High slopes propagate over large distances without dissipating the steepest features. Both the propagation velocity and the dynamically selected slope are universal, independent of the details of the initial shape of the surface. The resulting behavior can be understood as the propagation of a shock front that self-selects a stable slope, as has been previously observed in thin-film fluid flows. Experiments confirm predictions of the theory. An important implication of the propagative behavior at high surface slopes is that a pattern can be fabricated at a large length scale and, through uniform ion irradiation, reduced to a smaller length scale while preserving, or even sharpening, the sharpest features.
Biological Transmission of Arboviruses: Reexamination of and New Insights into Components, Mechanisms, and Unique Traits as Well as Their Evolutionary Trends
Authors: Kuno Goro , Chang Gwong-Jen J.
Published: October 2005

Among animal viruses, arboviruses are unique in that they depend on arthropod vectors for transmission. Field research and laboratory investigations related to the three components of this unique mode of transmission, virus, vector, and vertebrate host, have produced an enormous amount of valuable information that may be found in numerous publications. However, despite many reviews on specific viruses, diseases, or interests, a systematic approach to organizing the available information on all facets of biological transmission and then to interpret it in the context of the evolutionary process has not been attempted before. Such an attempt in this review clearly demonstrates tremendous progress made worldwide to characterize the viruses, to comprehend disease transmission and pathogenesis, and to understand the biology of vectors and their role in transmission. The rapid progress in molecular biologic techniques also helped resolve many virologic puzzles and yielded highly valuable data hitherto unavailable, such as characterization of virus receptors, the genetic basis of vertebrate resistance to viral infection, and phylogenetic evidence of the history of host range shifts in arboviruses. However, glaring gaps in knowledge of many critical subjects, such as the mechanism of viral persistence and the existence of vertebrate reservoirs, are still evident. Furthermore, with the accumulated data, new questions were raised, such as evolutionary directions of virus virulence and of host range. Although many fundamental questions on the evolution of this unique mode of transmission remained unresolved in the absence of a fossil record, available observations for arboviruses and the information derived from studies in other fields of the biological sciences suggested convergent evolution as a plausible process. Overall, discussion of the diverse range of theories proposed and observations made by many investigators was found to be highly valuable for sorting out the possible mechanism(s) of the emergence of arboviral diseases.
Tick-Borne Rickettsioses around the World: Emerging Diseases Challenging Old Concepts
Authors: Parola Philippe , Paddock Christopher D. , Raoult Didier
Published: October 2005

During most of the 20th century, the epidemiology of tick-borne rickettsioses could be summarized as the occurrence of a single pathogenic rickettsia on each continent. An element of this paradigm suggested that the many other characterized and noncharacterized rickettsiae isolated from ticks were not pathogenic to humans. In this context, it was considered that relatively few tick-borne rickettsiae caused human disease. This concept was modified extensively from 1984 through 2005 by the identification of at least 11 additional rickettsial species or subspecies that cause tick-borne rickettsioses around the world. Of these agents, seven were initially isolated from ticks, often years or decades before a definitive association with human disease was established. We present here the tick-borne rickettsioses described through 2005 and focus on the epidemiological circumstances that have played a role in the emergence of the newly recognized diseases.
REPRESENTATION OF SEMIAUTOMATA BY CANONICAL WORDS AND EQUIVALENCES
Authors: BRZOZOWSKI JANUSZ , JÜRGENSEN HELMUT
Published: October 2005

We study a novel representation of semiautomata, which is motivated by the method of trace-assertion specifications of software modules. Each state of the semiautomaton is represented by an arbitrary word leading to that state, the canonical word. The transitions of the semiautomaton give rise to a right congruence, the state-equivalence, on the set of input words of the semiautomaton: two words are state-equivalent if and only if they lead to the same state. We present a simple algorithm for finding a set of generators for state-equivalence. Directly from this set of generators, we construct a confluent prefix-rewriting system which permits us to transform any word to its canonical representative. In general, the rewriting system may allow infinite derivations. To address this issue, we impose the condition of prefix-continuity on the set of canonical words. A set is prefix-continuous if, whenever a word w and a prefix u of w are in the set, then all the prefixes of w longer than u are also in the set. Prefix-continuous sets include prefix-free and prefix-closed sets as special cases. We prove that the rewriting system is Noetherian if and only if the set of canonical words is prefix-continuous. Furthermore, if the set of canonical words is prefix-continuous, then the set of rewriting rules is irredundant. We show that each prefix-continuous canonical set corresponds to a spanning forest of the semiautomaton.
COVER TRANSDUCERS FOR FUNCTIONS WITH FINITE DOMAIN
Authors: CHAMPARNAUD JEAN-MARC , GUINGNE FRANCK , HANSEL GEORGES
Published: October 2005

Cover automata were introduced a few years ago for designing a compact representation of finite languages. Our aim is to extend this notion to cover transducers for functions with finite domain. Given two alphabets Σ and Ω, and a function α : Σ* → Ω* of order l (the maximal length of a word in the domain of α), a cover transducer for α is any subsequential transducer that realizes the function α when its input is restricted to the set of words of Σ* having a length not greater than l. We study the problem of reducing the number of states of a cover transducer. We report experimental results, from an implementation using WFSC (Weighted Finite State Compiler), a Xerox tool for handling weighted finite state automata and transducers.
ADVICE FOR SEMIFEASIBLE SETS AND THE COMPLEXITY-THEORETIC COST(LESSNESS) OF ALGEBRAIC PROPERTIES
Authors: FALISZEWSKI PIOTR , HEMASPAANDRA LANE A.
Published: October 2005

Informally put, the semifeasible sets are the class of sets having a polynomial-time algorithm that, given as input any two strings of which at least one belongs to the set, will choose one that does belong to the set. We provide a tutorial overview of the advice complexity of the semifeasible sets. No previous familiarity with either the semifeasible sets or advice complexity will be assumed, and when we include proofs we will try to make the material as accessible as possible via providing intuitive, informal presentations.

Karp and Lipton introduced advice complexity about a quarter of a century ago.18 Advice complexity asks, for a given power of interpreter, how many bits of "help" suffice to accept a given set. Thus, this is a notion that contains aspects both of descriptional/informational complexity and of computational complexity. We will see that for some powers of interpreter the (worst-case) complexity of the semifeasible sets is known right down to the bit (and beyond), but that for the most central power of interpreter—deterministic polynomial time—the complexity is currently known only to be at least linear and at most quadratic.

While overviewing the advice complexity of the semifeasible sets, we will stress also the issue of whether the functions at the core of semifeasibility—so-called selector functions—can without cost be chosen to possess such algebraic properties as commutativity and associativity. We will see that this is relevant, in ways both potential and actual, to the study of the advice complexity of the semifeasible sets.
THE PHENOMENON OF NON-RECURSIVE TRADE-OFFS
Authors: KUTRIB MARTIN
Published: October 2005

Non-recursive trade-offs between different representations of languages reveal a basic phenomenon. The gain in economy of description can be arbitrary. The purpose of this paper is to survey the main aspects and results regarding different representations of languages whose relative succinctness is not recursively bounded. Basic properties of descriptional systems and reasonable size measures are addressed, and the unified fundamental proof schemes emerging from the literature are presented. A comprehensive overview of results is given. Finally, some new results are shown. In particular, it is proved that between each two levels of the infinite one-way k-head finite automata hierarchies there is a non-recursive trade-off. Moreover, non-recursive trade-offs are shown between nondeterministic 2-head and deterministic k-head automata.
PROPER ACTIONS ON SOME EXPONENTIAL SOLVABLE HOMOGENEOUS SPACES
Authors: BAKLOUTI ALI , KHLIF FATMA
Published: October 2005

Let G be a connected, simply connected nilpotent Lie group, H and K be connected subgroups of G. We show in this paper that the action of K on X = G/H is proper if and only if the triple (G,H,K) has the compact intersection property in both cases where G is at most three-step and where G is special, extending then earlier cases. The result is also proved for exponential homogeneous space on which acts a maximal subgroup.
ELLIPTIC GENERA, TORUS ORBIFOLDS AND MULTI-FANS
Authors: HATTORI AKIO , MASUDA MIKIYA
Published: October 2005

Multi-fan is an analogous notion of fan in toric theory. Fan is a combinatorial object associated to a toric variety. Multi-fan is associated to an orbifold with an action of half the dimension of the orbifold. In this paper the equivariant elliptic genus and the equivariant orbifold elliptic genus of multi-fans are defined and their character formulas are exhibited. A vanishing theorem concerning elliptic genus of multi-fans of global type and its applications to toric varieties are given.
ELECTRON GAS STATISTICS IN SIZE-QUANTIZED THIN FILMS WITH NON-PARABOLIC ENERGY SPECTRA
Authors: EMİNBEYLİ RAMAZAN , GULİYEV BAHŞELI , DEMİREL ALI IHSAN , YAMAN ABUZER
Published: October 2005

The electron gas statistics in semiconducting thin films with arbitrary isotropic energy spectra was found in this theoretical work. General expressions for the density of states of the charge carriers and for the chemical potential were deduced according to the two-band Kane model approach. The ratio of the expression obtained for the density of states to that of the expression deduced according to the parabolic approach was shown to be a function of the energy. The Fermi energy of the electron gas was observed to be a function of the thin film thickness, the non-parabolic parameter, the concentration and the temperature. In the strong non-parabolic approach the dependency of the Fermi energy on the thin film thickness was shown to exhibit non-monotonic characteristics.
ELECTRONIC TRANSPORT PROPERTIES OF α-TiAl ALLOYS
Authors: ZHANG DIANLIN , LIU SHUMEI , JING XIUNIAN , LUO JIANLIN , ZHANG X.-G. , WANG RUJU , KANG NING , CHEN ZHAOJIA , LI LU , LIN J. J.
Published: October 2005

The electrical resistivity, thermal conductivity, and thermopower of α -TiAl alloy samples with Al content from 0 at.% to 10 at.% are measured from room temperature down to liquid helium temperature. It is found that with the increase in Al content the single phonon scattering contribution to the resistivity remains nearly constant, but the multi-phonon scattering contribution monotonously increases. This provides an alternative explanation of resistivity saturation to the shunt-resistor model. The Wiedemann–Franz law holds for the whole temperature range, allowing the separation of the electron and phonon contributions to the thermal conductivity. The data from samples with different doping levels enable us to separate the band and the scattering terms in the thermopower.
EXPLOITING OPTIMAL CONTROL FOR TARGET-ORIENTED MANIPULATION OF (BIO)CHEMICAL SYSTEMS: A MODEL-BASED APPROACH TO SPECIFIC MODIFICATION OF SELF-ORGANIZED DYNAMICS
Authors: LEBIEDZ D.
Published: October 2005

In this paper we review recent progress in the development and application of advanced optimal control methods for target-oriented manipulation of self-organized dynamics in (bio)chemical reaction systems. We discuss results related to nonlinear model-based external control aimed at forcing and stabilization of spatiotemporal pattern formation and specific driving, phase resetting and annihilation of limit cycle oscillators. We refer to both open-loop and feedback optimal control approaches. Optimal control strategies for self-organized systems may be highly beneficial in applications concerned with steering of technical processes in open non-equilibrium systems and specific manipulation of self-organized cellular dynamics in biomedicine.
A MULTI-COUNTRY COMPARISON OF PERCEIVED ENVIRONMENTAL CHARACTERISTICS, INDUSTRY EFFECTS, AND PERFORMANCE IN ENTREPRENEURIAL FIRMS
Authors: ARBAUGH J. B. , CAMP S. MICHAEL , COX LARRY W.
Published: October 2005

This paper examines the relationship between industry effects, environmental perceptions, and firm performance in a multi-country sample of entrepreneurial firms. Using a sample of 1045 finalists in Ernst & Young's International "Entrepreneur of the Year" competition, we examined whether environmental constructs that have been studied and validated in North American entrepreneurship research were generalizable to firms in fifteen countries located in Europe, Asia, and Africa. Using measures common to North American entrepreneurship research; we identified two environmental dimensions in subsamples of North American (United States and Canada) and non-North American firms: dynamism and hostility. However, while the constructs were identified in both subsamples, they also were not significantly associated with firm performance. We conclude the paper by suggesting this lack of environmental perception-firm performance relationship may be attributable to an entrepreneurial mindset that focuses on identifying and recognizing specific opportunities rather than responding to general characteristics of the external environment.
ORGANIZING NEW VENTURE SUPPORT IN REGIONAL NETWORKS: EXPLORING EVIDENCE FROM 'EXIST – ENTREPRENEURS FROM UNIVERSITIES' IN GERMANY
Authors: KOCH LAMBERT T. , KAUTONEN TEEMU
Published: October 2005

New Venture Support Networks (NVSN) are a political instrument with the aim of improving coordination between private and public organizations involved in new venture support in a region. Cooperation between these organizations should improve the overall quality of new venture support and increase its transparency to potential entrepreneurs. However, achieving cooperation between organizations with heterogeneous interests is particularly difficult when the network has been initiated 'artificially' as part of a political programme. This paper examines the concept of NVSN theoretically focusing on network cooperation, and illustrates the concepts with empirical examples from exploratory interviews conducted in five NVSN established in 1998 in Germany within the government initiative 'EXIST – Entrepreneurs from Universities'. The preliminary conclusions suggest that there is a need for improvement and further investigation concerning the framework of rules and incentives set by the political programme, and the roles of certain key actors as 'motors' of self-organization in NVSN.
Isovolumic pressure-to-early rapid filling decay rate relation: model-based derivation and validation via simultaneous catheterization echocardiography
Authors: Chung Charles S. , Ajo David M. , Kovács Sándor J.
Published: October 2005

Transmitral Doppler echocardiography is the preferred method of noninvasive diastolic function assessment. Correlations between catheterization-based measures of isovolumic relaxation (IVR) and transmitral, early rapid filling (Doppler E-wave)-derived parameters have been observed, but no model-based, causal explanation has been offered. IVR has also been characterized in terms of its duration as IVR time (IVRT) and by τ, the time-constant of IVR, by approximating the terminal left ventricular IVR pressure contour as P( t) = P∞ + Po e− t/τ, where P( t) is the continuity of pressure, P∞ and Po are constants, t is time, and τ is the time constant of IVR. To characterize the relation between IVR and early rapid filling more fully, simultaneous (micromanometric) left ventricular pressure and transmitral Doppler E-wave data from 25 subjects undergoing elective cardiac catheterization and having normal physiology were analyzed. The time constant τ was determined from the dP /d t vs. P (phase) plane and, simultaneous Doppler E-waves provided global indexes of chamber viscosity/relaxation ( c), chamber stiffness ( k), and load ( xo). We hypothesize that temporal continuity of pressure decay at mitral valve opening and physiological constraints permit the algebraic derivation of linear relations relating 1/τ to both peak atrioventricular pressure gradient ( kxo) and E-wave-derived viscosity/relaxation ( c) but does not support a similar, causal (linear) relation between deceleration time and τ or IVRT. Both predicted linear relations were observed: kxo to 1/τ ( r = 0.71) and viscosity/relaxation to 1/τ ( r = 0.71). Similarly, as anticipated, only a weak linear correlation between deceleration time and IVRT or τ was observed ( r = 0.41). The observed in vivo relationship provides insight into the isovolumic mechanism of relaxation and the changing-volume mechanism of early rapid filling via a link of the respective relaxation properties.
Acute effects of cold exposure on central aortic wave reflection
Authors: Edwards David G. , Gauthier Amie L. , Hayman Melissa A. , Lang Jesse T. , Kenefick Robert W.
Published: October 2005

The purpose of this study was to determine the effects of acute cold exposure on the timing and amplitude of central aortic wave reflection and central pressure. We hypothesized that cold exposure would result in an early return of reflected pressure waves from the periphery and an increase in central aortic systolic pressure as a result of cold-induced vasoconstriction. Twelve apparently healthy men (age 27.8 ± 2.0 yr) were studied at random, in either temperate (24°C) or cold (4°C) conditions. Measurements of brachial artery blood pressure and the synthesis of a central aortic pressure waveform (by noninvasive radial artery applanation tonometry and use of a generalized transfer) were conducted at baseline and after 30 min in each condition. Central aortic augmentation index (AI), an index of wave reflection, was calculated from the aortic pressure waveform. Cold induced an increase ( P < 0.05) in AI from 3.4 ± 1.9 to 19.4 ± 1.8%. Cold increased ( P < 0.05) both brachial and central systolic pressure; however, the magnitude of change in central systolic pressure was greater ( P < 0.05) than brachial (13 vs. 2.5%). These results demonstrate that cold exposure and the resulting peripheral vasoconstriction increase wave reflection and central systolic pressure. Additionally, alterations in central pressure during cold exposure were not evident from measures of brachial blood pressure.