bluuebunny/crossref_metadata_2025 huggingface dataset:
Complete transmission through a periodically perforated rigid slab
Authors: Zhou Lin , Kriegsmann Gregory A.
Published: June 2007

The propagation of a normally incident plane acoustic wave through a three-dimensional rigid slab with periodically placed holes is modeled and analyzed. The spacing of the holes A and B, the wavelength λ, and the thickness of the slab L are order one parameters compared to the characteristic size D of the holes, which is a small quantity. Scattering matrix techniques are used to derive expressions for the transmission and reflection coefficients of the lowest mode. These expressions depend only on the transmission coefficient, τ0, of an infinitely long slab with the same configuration. The determination of τ0 requires the solution of an infinite set of algebraic equations. These equations are approximately solved by exploiting the small parameter D∕AB. Remarkably, this structure is transparent at certain frequencies and opaque for all others. Such a structure may be useful in constructing narrow-band filters and resonators.
Effect of nuclei concentration on cavitation cluster dynamics
Authors: Arora M. , Ohl C. D. , Lohse D.
Published: June 2007

Cavitation cluster dynamics after the passage of a single pressure wave is studied for different concentrations of artificial cavitation nuclei (30 to 3×105nuclei∕ml). With increasing concentration of cavitation nuclei the lifetime of the cavitation cluster is prolonged. Additionally, it is found that the spatial extent of the cluster decreases with higher nuclei concentration. The experimental data for concentrations less than 400nuclei∕ml are compared to simulations with a Rayleigh-Plesset-type equation, taking into account bubble-bubble interaction. For higher concentrations (more than 1000nuclei∕ml) the observed radial cluster dynamics is compared with calculations from an axisymmetric cavity-collapse model.
Properties of an entropy-based signal receiver with an application to ultrasonic molecular imaging
Authors: Hughes M. S. , McCarthy J. E. , Marsh J. N. , Arbeit J. M. , Neumann R. G. , Fuhrhop R. W. , Wallace K. D. , Znidersic D. R. , Maurizi B. N. , Baldwin S. L. , Lanza G. M. , Wickline S. A.
Published: June 2007

Qualitative and quantitative properties of the finite part, Hf, of the Shannon entropy of a continuous waveform f(t) in the continuum limit are derived in order to illuminate its use for waveform characterization. Simple upper and lower bounds on Hf, based on features of f(t), are defined. Quantitative criteria for a priori estimation of the average-case variation of Hf and logEf, where Ef is the signal energy of f(t) are also derived. These provide relative sensitivity estimates that could be used to prospectively choose optimal imaging strategies in real-time ultrasonic imaging machines, where system bandwidth is often pushed to its limits. To demonstrate the utility of these sensitivity relations for this application, a study designed to assess the feasibility of identification of angiogenic neovasculature targeted with perfluorocarbon nanoparticles that specifically bind to αvβ3-integrin expression in tumors was performed. The outcome of this study agrees with the prospective sensitivity estimates that were used for the two receivers. Moreover, these data demonstrate the ability of entropy-based signal receivers when used in conjunction with targeted nanoparticles to elucidate the presence of αvβ3 integrins in primordial neovasculature, particularly in acoustically unfavorable environments.
Caller sex and orientation influence spectral characteristics of “two-voice” stereotyped calls produced by free-ranging killer whales
Authors: Miller Patrick J. O. , Samarra Filipa I. P. , Perthuison Aurélie D.
Published: June 2007

This study investigates how particular received spectral characteristics of stereotyped calls of sexually dimorphic adult killer whales may be influenced by caller sex, orientation, and range. Calls were ascribed to individuals during natural behavior using a towed beamforming array. The fundamental frequency of both high-frequency and low-frequency components did not differ consistently by sex. The ratio of peak energy within the fundamental of the high-frequency component relative to summed peak energy in the first two low-frequency component harmonics, and the number of modulation bands off the high-frequency component, were significantly greater when whales were oriented towards the array, while range and adult sex had little effect. In contrast, the ratio of peak energy in the first versus second harmonics of the low-frequency component was greater in calls produced by adult females than adult males, while orientation and range had little effect. The dispersion of energy across harmonics has been shown to relate to body size or sex in terrestrial species, but pressure effects during diving are thought to make such a signal unreliable in diving animals. The observed spectral differences by signaler sex and orientation suggest that these types of information may be transmitted acoustically by freely diving killer whales.
The effects of prosodic boundaries on nasality in Taiwan Min
Authors: Pan Ho-hsien
Published: June 2007

This study explores the effects of prosodic boundaries on nasality at intonational phrase, word, and syllable boundaries. The subjects were recorded saying phrases that contained a syllable-final nasal consonant followed by a syllable-initial stop. The timing, duration, and magnitude of the nasal airflows measured were used to determine the extent of nasality across boundaries. Nasal amplitudes were found to vary in a speaker-dependent manner among boundary types. However, the patterns of nasal contours and temporal aspects of the airflow parameters consistently varied with boundary type across all the speakers. In general, the duration of nasal airflow and nasal plateau were the longest at the intonational phrase boundary, followed by word boundary and then syllable boundary. In addition to the hierarchical influence of boundary strength, there were unique phonetic markings associated with individual boundaries. In particular, two nasal rises interrupted by nasal inhalation occurred only across an intonation phrase boundary. Also, unexpectedly, a word boundary was marked by the longest postboundary vowel, whereas a syllable boundary was marked with the shortest nasal duration. The results here support the hierarchical effect of boundary on both domain-edge strengthening and cross-boundary coarticulation.
Transverse pressure distributions in a simple model ear canal occluded by a hearing aid test fixture
Authors: Stinson M. R. , Daigle G. A.
Published: June 2007

The sound field in a model ear canal with a hearing aid test fixture has been investigated experimentally and theoretically. Large transverse variations of sound pressure level, as much as 20dB at 8kHz, were found across the inner face of the hearing aid. Variations are greatest near the outlet port of the receiver and the vent port. Deeper into the canal, the transverse variations are less significant and, at depths greater than 4mm, only a longitudinal variation remains. The model canal was cylindrical, 7.5mm diameter, and terminated with a Zwislocki coupler to represent absorption by the human middle ear. The outer end of the canal was driven by the receiver in the hearing aid test fixture, with the acoustic output entering the canal through a 1mm port. The hearing aid was provided with a 20-mm-long vent, either 1 or 2mm in diameter. The sound field inside the canal was measured using a specially designed 0.2-mm-diam probe microphone [Daigle and Stinson, J. Acoust. Soc. Am. 116, 2618 (2004)]. In parallel, calculations of the interior sound field were performed using a boundary element technique and found to agree well with measurements.
Low-frequency characteristics of human and guinea pig cochleae
Authors: Marquardt Torsten , Hensel Johannes , Mrowinski Dieter , Scholz Gűnther
Published: June 2007

Previous physiological studies investigating the transfer of low-frequency sound into the cochlea have been invasive. Predictions about the human cochlea are based on anatomical similarities with animal cochleae but no direct comparison has been possible. This paper presents a noninvasive method of observing low frequency cochlear vibration using distortion product otoacoustic emissions (DPOAE) modulated by low-frequency tones. For various frequencies (15–480Hz), the level was adjusted to maintain an equal DPOAE-modulation depth, interpreted as a constant basilar membrane displacement amplitude. The resulting modulator level curves from four human ears match equal-loudness contours (ISO226:2003) except for an irregularity consisting of a notch and a peak at 45Hz and 60Hz, respectively, suggesting a cochlear resonance. This resonator interacts with the middle ear stiffness. The irregularity separates two regions of the middle ear transfer function in humans: A slope of 12dB∕octave below the irregularity suggests mass-controlled impedance resulting from perilymph movement through the helicotrema; a 6-dB/octave slope above the irregularity suggests resistive cochlear impedance and the existence of a traveling wave. The results from four guinea pig ears showed a 6-dB/octave slope on either side of an irregularity around 120Hz, and agree with published data.
An extended coupled phase theory for the sound propagation in polydisperse concentrated suspensions of rigid particles
Authors: Baudoin Michael , Thomas Jean-Louis , Coulouvrat François , Lhuillier Daniel
Published: June 2007

An extension of the classical coupled phase theory is proposed to account for hydrodynamic interactions between neighboring rigid particles, which are essential to describe properly the sound propagation in concentrated suspensions. Rigorous ensemble-averaged equations are derived for each phase and simplified in the case of acoustical wave propagation. Then, closure is achieved by introducing a self-consistent scheme originally developed by Buyevich and Shchelchkova [Prog. Aerosp. Sci. 18, 121–151 (1978)] for incompressible flows, to model the transfer terms between the two phases. This provides an alternative to the effective medium self-consistent theory developed by Spelt et al. [J. Fluid Mech. 430, 51–86 (2001)] in which the suspension is considered as a whole. Here, a significantly simpler formulation is obtained in the long wavelength regime. Predictions of this self-consistent theory are compared with the classical coupled phase theory and with experimental data measuring the attenuation in concentrated suspensions of silica in water. Our calculation is shown to give a good description of the attenuation variation with volume fraction. This theory is also extended to the case of polydisperse suspensions. Finally, the link between the self-consistent theory and the different orders of the multiple scattering theory is clarified.
Near-field time-reversal amplification
Authors: Conti Stephane G. , Roux Philippe , Kuperman William A.
Published: June 2007

The spatial resolution of the focused field of a classical time-reversal mirror has a wavelength-order λ diffraction limit. Previously reported results for subwavelength focus require either the full knowledge of the original source or the evanescent waves in the near field. Here it is shown that subwavelength focusing can be achieved without a priori knowledge of the original probe source. If the field is recorded at a few wavelengths away from the probe source, where the amplitude of the near field is too low for subwavelength focusing, it is shown that the low amplitude near field can be amplified and the spatial resolution improved, using the near-field time reversal (NTR) procedure introduced here. The NTR is performed from the phase of the spatial spectrum of the field recorded on an array around the original probe source using an analytical continuation for the amplitude of the spatial spectrum. Following theory, λ∕20 resolution is experimentally demonstrated with audible acoustic wavefields in the air.
Directionality of generalized acoustic sensors of arbitrary order
Authors: Schmidlin Dean J.
Published: June 2007

For several decades there has been a great deal of interest in acoustic sensors that can make multiple measurements at a single point in the ocean. The order of such sensors has been defined by linking it to the order of the Taylor series approximation of the pressure field at that point. Following this definition, the pressure, vector, and dyadic sensor is of order zero, one, and two, respectively. For this theoretical study, a multichannel three-dimensional spatial filter is derived for a directional acoustic sensor of arbitrary order. Explicit formulas are found for the filter coefficients that maximize the array gain (directivity index) of the filter as well as an explicit expression for the maximum array gain (directivity index). This process is repeated for the case of a first-order null placed in the direction opposite to the look direction of the multichannel filter. Finally, an example is presented which tracks the array gain and beamwidth of a third-order acoustic sensor as the order of the null is assigned values 0, 1, 2, and 3.
Ceiling baffles and reflectors for controlling lecture-room sound for speech intelligibility
Authors: Yang Wonyoung , Hodgson Murray
Published: June 2007

Reinforcing speech levels and controlling noise and reverberation are the ultimate acoustical goals of lecture-room design to achieve high speech intelligibility. The effects of sound absorption on these factors have opposite consequences for speech intelligibility. Here, novel ceiling baffles and reflectors were evaluated as a sound-control measure, using computer and 1/8-scale models of a lecture room with hard surfaces and excessive reverberation. Parallel ceiling baffles running front to back were investigated. They were expected to absorb reverberation incident on the ceiling from many angles, while leaving speech signals, reflecting from the ceiling to the back of the room, unaffected. Various baffle spacings and absorptions, central and side speaker positions, and receiver positions throughout the room, were considered. Reflective baffles controlled reverberation, with a minimum decrease of sound levels. Absorptive baffles reduced reverberation, but reduced speech levels significantly. Ceiling reflectors, in the form of obstacles of semicircular cross section, suspended below the ceiling, were also tested. These were either 7m long and in parallel, front-to-back lines, or 0.8m long and randomly distributed, with flat side up or down, and reflective or absorptive top surfaces. The long reflectors with flat side down and no absorption were somewhat effective; the other configurations were not.
Optical measurements of the self-demodulated displacement and its interpretation in terms of radiation pressure
Authors: Rénier Mathieu , Barrière Christophe , Royer Daniel
Published: June 2007

Using a sensitive optical interferometer, the low frequency displacement nonlinearly generated by an ultrasonic tone burst propagating in a liquid is studied. Close to the source, the low frequency displacement contains a quasi-static component, which is affected by diffraction effects farther from the transducer. The experimental setup provides quantitative results, which allow the determination of the nonlinearity parameter of the liquid with a good accuracy. Such measurements are carried out in water and ethanol. Finally, the pressure associated with the low frequency displacement is discussed. Introducing the temporal mean value of the displacement, as already done in lossless solids, the noncumulative part of this second order pressure is associated with the static part of the low frequency displacement. This interpretation leads to extend the definition of the Rayleigh radiation pressure usually introduced for a continuous plane wave radiated in a confined fluid.
Vocal tract length perturbation and its application to male-female vocal tract shape conversion
Authors: Adachi Seiji , Takemoto Hironori , Kitamura Tatsuya , Mokhtari Parham , Honda Kiyoshi
Published: June 2007

An alternative and complete derivation of the vocal tract length sensitivity function, which is an equation for finding a change in formant frequency due to perturbation of the vocal tract length [Fant, Quarterly Progress and Status Rep. No. 4, Speech Transmission Laboratory, Kungliga Teknisha Högskolan, Stockholm, 1975, pp. 1–14] is presented. It is based on the adiabatic invariance of the vocal tract as an acoustic resonator and on the radiation pressure on the wall and at the exit of the vocal tract. An algorithm for tuning the vocal tract shape to match the formant frequencies to target values, such as those of a recorded speech signal, which was proposed in Story [J. Acoust. Soc. Am. 119, 715–718 (2006)], is extended so that the vocal tract length can also be changed. Numerical simulation of this extended algorithm shows that it can successfully convert between the vocal tract shapes of a male and a female for each of five Japanese vowels.
Classifying multi-frequency fisheries acoustic data using a robust probabilistic classification technique
Authors: Anderson C. I. H. , Horne J. K. , Boyle J.
Published: June 2007

A robust probabilistic classification technique, using expectation maximization of finite mixture models, is used to analyze multi-frequency fisheries acoustic data. The number of clusters is chosen using the Bayesian Information Criterion. Probabilities of membership to clusters are used to classify each sample. The utility of the technique is demonstrated using two examples: the Gulf of Alaska representing a low-diversity, well-known system; and the Mid-Atlantic Ridge, a species-rich, relatively unknown system.
High frequency vibration analysis by the complex envelope vectorization
Authors: Giannini O. , Carcaterra A. , Sestieri A.
Published: June 2007

The complex envelope displacement analysis (CEDA) is a procedure to solve high frequency vibration and vibro-acoustic problems, providing the envelope of the physical solution. CEDA is based on a variable transformation mapping the high frequency oscillations into signals of low frequency content and has been successfully applied to one-dimensional systems. However, the extension to plates and vibro-acoustic fields met serious difficulties so that a general revision of the theory was carried out, leading finally to a new method, the complex envelope vectorization (CEV). In this paper the CEV method is described, underlying merits and limits of the procedure, and a set of applications to vibration and vibro-acoustic problems of increasing complexity are presented.
An alternative Biot’s displacement formulation for porous materials
Authors: Dazel Olivier , Brouard Bruno , Depollier Claude , Griffiths Stéphane
Published: June 2007

This paper proposes an alternative displacement formulation of Biot’s linear model for poroelastic materials. Its advantage is a simplification of the formalism without making any additional assumptions. The main difference between the method proposed in this paper and the original one is the choice of the generalized coordinates. In the present approach, the generalized coordinates are chosen in order to simplify the expression of the strain energy, which is expressed as the sum of two decoupled terms. Hence, new equations of motion are obtained whose elastic forces are decoupled. The simplification of the formalism is extended to Biot and Willis thought experiments, and simpler expressions of the parameters of the three Biot waves are also provided. A rigorous derivation of equivalent and limp models is then proposed. It is finally shown that, for the particular case of sound-absorbing materials, additional simplifications of the formalism can be obtained.
An articulatory basis for the labial-to-coronal effect: /pata/ seems a more stable articulatory pattern than /tapa/
Authors: Rochet-Capellan Amélie , Schwartz Jean-Luc
Published: June 2007

This paper investigates the coordination between the jaw, the tongue tip, and the lower lip during repetition with rate increase of labial-to-coronal (LaCo) consonant-vowel-consonant-vowel disyllables (e.g., /pata/) and coronal-to-labial (CoLa) ones (e.g., /tapa/) by French speakers. For the two types of disyllables: (1) the speeding process induces a shift from two jaw cycles per disyllable to a single cycle; (2) this shift modifies the coordination between the jaw and the constrictors, and (3) comes with a progression toward either a LaCo attractor [e.g., (/pata/ or /tapa/) → /patá/ → /ptá/] or a CoLa one (e.g., /pata/ or /tapa/ → /tapá/ → /tpá/). Yet, (4) the LaCo attractor is clearly favored regardless of the initial sequencing. These results are interpreted as evidence that a LaCo CVCV disyllable could be a more stable coordinative pattern for the lip-tongue-jaw motor system than a CoLa one. They are discussed in relation with the so-called LC effect that is the preference for LaCo associations rather than CoLa ones in CV.CV disyllables in both world languages and infants’ first words.
Resonant frequency shifts induced by a large spherical object in an air-filled acoustic cavity
Authors: Cordero María Luisa , Mujica Nicolás
Published: June 2007

Acoustic resonances are modified when objects are introduced into a chamber. The magnitude of these changes depends on the object position, size, and shape, as well as on its acoustic properties. Here, an experimental study concerning the resonant frequency shifts induced by a solid spherical object in a quasi-one-dimensional air-filled acoustic cavity is reported. It is shown that Leung’s theory does not account quantitatively for the observations. A novel and simple approach is proposed, based on the wave equation in a cavity of variable cross section. The results fit more accurately the measured frequency shifts.
Hybrid passive-active absorption of a microperforated panel in free field conditions
Authors: Cobo Pedro , Cuesta María
Published: June 2007

Although hybrid passive-active absorption in impedance tubes has been widely analyzed, its study in more realistic conditions remains to be accomplished. This letter describes the practical measurement of the passive-active absorption coefficient in a free field. The passive absorber consists of a microperforated panel backed by an air cavity and a wooden panel. A multichannel active system controls the sound pressure in a reduced cell behind the absorber. Measured absorption coefficients between 200 and 400Hz account for 0.2–0.4 and 0.72–0.75, in the passive and active cases, respectively, and above 500Hz both are comparable.
The production of English corner vowels by English as a foreign language children learners in Taiwan
Authors: Wu E-chin
Published: June 2007

This study aims to test whether EFL children learners in Taiwan would differentiate between the similar but not totally identical corner vowels /i/, /u/, and /a/ in English and Chinese. A picture naming task incorporated with a word guessing game was conducted on 12 subjects to collect vowel samples for acoustic analysis. The acoustic features being examined were the first and second formants. Results showed a tendency for the EFL children learners to distinguish between the Chinese and English corner vowels. This suggested that early EFL learners may possibly have separated sound systems created for different languages.
Auditory evoked potential hearing measures of a group of bottlenosed dolphins (Tursiops truncatus)
Authors: Taylor Kristen A. , Nachtigall Paul E. , Amundin Mats , Mosesson Pernilla , Edberg Sunna , Karlsson Stina
Published: June 2007

The hearing of the bottlenosed dolphins at Kolmrdens Djurpark, Sweden, was examined using a portable auditory evoked potential (AEP) system in order to examine the hearing capabilities of dolphins housed in quiet environments with an emphasis on age-related hearing variation. Audiograms were measured on two dolphins and modulation rate transfer functions (MRTF) were also measured on two animals. A complete audiogram (4–200 kHz) was obtained for the oldest dolphin, a 34 year old female named Vicky. Her audiogram showed no evidence of high-frequency hearing loss. Notwithstanding this finding, her click evoked auditory brainstem response (ABR) revealed a marked increase in interpeak latency that could be indicative of an underlying hearing defect. The audiogram obtained from for the male dolphin, a 24 year old named Pichi (measured from 4–107 kHz), demonstrated profound hearing loss at all frequencies. The measured MRTF results indicated typical odontocete following responses to rates exceeding 1000 Hz.
Acid reflux into the oesophagus does not influence exercise-induced airway narrowing in bronchial asthma
Authors: Ferrari M , Bonella F , Benini L , Ferrari P , De Iorio F , Testi R , Lo Cascio V
Published: June 2007

Objectives:

A few studies on small patient series have investigated the relationship between gastroesophageal reflux and bronchial responsiveness as expressed by exercise-induced bronchoconstriction (EIB), with non-conclusive results. The aim of this study was to evaluate whether the presence of acid in the oesophagus may influence EIB.

Methods:

45 patients with bronchial asthma underwent spirometry, exercise challenge on bicycle ergometer and 24 h oesophageal pH monitoring. Subjects with EIB (Forced expiratory volume in the first second (FEV1)) percentage decrease after exercise (ΔFEV1) ⩾15%, n  =  28) were retested after a 2 week treatment course with omeprazole 40 mg/daily. Exercise at baseline was performed at the same time as oesophageal pH monitoring.

Results:

In basal condition, there was no difference in FEV1, acid exposure time or number of refluxes measured during 24 h pH monitoring between patients with and without EIB. There was no relationship between spirometry results and ΔFEV1 on one hand, and parameters of gastroesophageal reflux on the other. Nine patients with EIB (31.0%) and six patients without EIB (37.5%) had one or more episodes of GER during exercise challenge, without significant differences between the two groups. After gastric acid inhibition by omeprazole, ΔFEV1 did not change significantly.

Conclusions:

The results indicate that acid in the oesophagus, or its short-term inhibition by proton pump inhibitors, has no influence on exercise-induced bronchoconstriction.
Yukon–Tanana terrane in the southern Campbell Range, Finlayson Lake belt, southeastern Yukon: the geological setting of retrogressed eclogite of the Klatsa metamorphic complex
Authors: Devine Fionnuala , Murphy Donald C , Carr Sharon D
Published: June 2007

Yukon–Tanana terrane in the southern Campbell Range is composed of rocks that have different metamorphic, exhumation, and structural histories, and that have formed in disparate parts of the Paleozoic Yukon–Tanana volcanic arc. The geological relationships in the southern Campbell Range reveal the tectonic and structural history of the Klatsa metamorphic complex, which represents the remnants of an Early Mississippian subduction zone beneath the Yukon–Tanana arc. The Klatsa metamorphic complex is composed of foliated to massive serpentinite, leucogabbro, amphibolite, and retrogressed eclogitic quartz–muscovite schist with lenses of metabasite. It was structurally juxtaposed on Upper Mississippian to Lower Permian metasedimentary rocks of the White Lake, King Arctic, and Money Creek formations. Regional and local structural and stratigraphic relationships suggest that the Klatsa metamorphic complex is part of the Cleaver Lake thrust sheet, the structurally highest thrust sheet in a north- to northeast-vergent thrust belt that deformed the Yukon–Tanana terrane during the Early Permian. Restoration of the displacement on the Cleaver Lake and underlying thrust faults places the Klatsa metamorphic complex on the western margin of Yukon–Tanana terrane. Late Devonian to Early Mississippian subduction is thought to have occurred along this margin based on previous paleogeographic reconstructions. Generally north- to northeast-vergent D1 to D3 folds deformed the Klatsa metamorphic complex and adjacent metasedimentary rocks. Jurassic(?) D4 imbricate thrust faulting has, in part, reactivated the Cleaver Lake thrust fault contacts and imbricated the Klatsa metamorphic complex with metasedimentary rocks in fault panels that are repeated at a scale of 10 to hundreds of metres.
A diverse late-glacial (Mackinaw Phase) biota from Leamington, Ontario
Authors: Karrow P F , Morris T F , McAndrews J H , Morgan A V , Smith A J , Walker I R
Published: June 2007

A sand pit at Leamington, Ontario, in southeastern Essex County in the southernmost part of Canada, has yielded many taxa of fossil animals and plants that are dated over 13 000 BP. The fossils are of both terrestrial and freshwater origin, and comprise a surprisingly diverse but coherent assemblage of molluscs, ostracodes, Chironomidae, Coleoptera, Turbellaria, Trichoptera, and a few fish bone fragments. This is the oldest known postglacial occurrence in Ontario for all animal groups. Paleoenvironments indicated by the taxa range from boreal forest to tundra; taxa are an in situ assemblage with little transport or reworking. Although this site has yielded the richest fossil record of this age yet found in Ontario, previous finds at a few sites on the north edge of the eastern Erie basin and in the southern Huron basin indicate plants were well established in southwestern Ontario by the time of the Mackinaw Phase interstadial when lowered lake levels likely facilitated their arrival from land areas to the south. This discovery greatly improves the prospects of finding fossils of this age even though the known record is still extremely limited. The site represents fortuitous preservation and discovery, and amply demonstrates that glacial lakes of this time, when much of the last ice sheet was still in existence, were far from barren of life and that the migration of biota into the area was quite rapid during ice retreat.
An efficient synthesis of carboxaldehyde derivatives of 4H-pyran-4-one
Authors: Teimuri-mofrad Reza , Abrishami Fatemeh
Published: June 2007

We developed a general method for the synthesis of various 2-mono- and 2,6-di-carboxaldehyde substituted derivatives of 3,5-diphenyl-4H-pyran-4-one and 4H-pyran-4-one. 3,5-Diphenyl-6-methyl-4-oxo-4H-pyran-2-carboxaldehyde (4a), 6-methyl-4-oxo-4H-pyran-2-carboxaldehyde (4b), 3,5-diphenyl-4-oxo-4H-pyran-2,6-dicarboxaldehyde (5a), 4-oxo-4H-pyran-2,6-dicarboxaldehyde (5b), 3,5-diphenyl-6-hydroxymethyl-4-oxo-4H-pyran-2-carboxaldehyde (10a), and 6-hydroxymethyl-4-oxo-4H-pyran-2-carboxaldehyde (10b) were obtained from the corresponding di-, tri-, and tetra-bromo derivatives of 2,6-dimethyl-3,5-diphenyl-4H-pyran-4-one (1a) and 2,6-dimethyl-4H-pyran-4-one (1b) by treatment with silver acetate followed by hydrolysis. Compounds 4a and 4b were also obtained by the oxidation of 10a and 10b with barium manganate.Key words: 4H-pyran-4-one, hydroxymethyl and carboxaldehyde derivatives, acetoxylation, hydrolysis, oxidation.
ON THE OTHER SIDE OF THE BIALGEBRA OF CHORD DIAGRAMS
Authors: TOURTCHINE V.
Published: June 2007

In this paper we describe complexes whose homologies are naturally isomorphic to the first term of the Vassiliev spectral sequence computing (co)homology of the spaces of long knots in ℝd, d ≥ 3. The first term of the Vassiliev spectral sequence is concentrated in some angle of the second quadrant. In homological case the lower line of this term is the bialgebra of chord diagrams (or its superanalog if d is even). We prove in this paper that the groups of the upper line are all trivial. In the same bigradings we compute the homology groups of the complex spanned only by strata of immersions in the discriminant (maps having only self-intersections). We interpret the obtained groups as subgroups of the (co)homology groups of the double loop space of a (d - 1)-dimensional sphere. In homological case the last complex is the normalized Hochschild complex of the Poisson or Gerstenhaber (depending on parity of d) algebras operad. The upper line bigradings are spanned by the operad of Lie algebras. To describe the cycles in these bigradings, we introduce new homological operations on Hochschild complexes. We show in future work that these operations are in fact the Dyer–Lashof–Cohen operations induced by the action of the singular chains operad of little squares on Hochschild complexes.
DEPTHS OF THE FOLIATIONS ON 3-MANIFOLDS EACH OF WHICH ADMITS EXACTLY ONE DEPTH 0 LEAF
Authors: MURAI HIROKO
Published: June 2007

In [2], Cantwell–Conlon introduced a knot invariant, called depth. In this paper, we discuss the depth of a foliation ℱ on a 3-manifold with ℱ being (*) "codimension one, transversely oriented, taut, and proper". We show that for each n > 0, there exists a 3-manifold M such that (minimal depth of ℱ on M with ℱ being (*) and having exactly one depth 0 leaf) is greater than (minimal depth of ℱ on M with ℱ being (*)) + n.
CLUSTERING-BASED NETWORK INTRUSION DETECTION
Authors: ZHONG SHI , KHOSHGOFTAAR TAGHI M. , SELIYA NAEEM
Published: June 2007

Recently data mining methods have gained importance in addressing network security issues, including network intrusion detection — a challenging task in network security. Intrusion detection systems aim to identify attacks with a high detection rate and a low false alarm rate. Classification-based data mining models for intrusion detection are often ineffective in dealing with dynamic changes in intrusion patterns and characteristics. Consequently, unsupervised learning methods have been given a closer look for network intrusion detection. We investigate multiple centroid-based unsupervised clustering algorithms for intrusion detection, and propose a simple yet effective self-labeling heuristic for detecting attack and normal clusters of network traffic audit data. The clustering algorithms investigated include, k-means, Mixture-Of-Spherical Gaussians, Self-Organizing Map, and Neural-Gas. The network traffic datasets provided by the DARPA 1998 offline intrusion detection project are used in our empirical investigation, which demonstrates the feasibility and promise of unsupervised learning methods for network intrusion detection. In addition, a comparative analysis shows the advantage of clustering-based methods over supervised classification techniques in identifying new or unseen attack types.
TYPING AND TRANSFORMATIONAL EFFECTS IN COMPLEX INFORMATION SUPPLY
Authors: VAN GILS B. , PROPER H. A. , VAN BOMMEL P. , VAN DER WEIDE T. P.
Published: June 2007

The amount of information available to us via the Web has increased enormously over the last few years. Even more, it seems that we are more and more dependent on this Web information in our day to day lives. Often we retrieve this information by querying the Web: data resources found on the web may provide the information that we are looking for. This implies that the Web may be seen as an information market: authors supply information and searchers may find it. In this article we present a formal reference model for the syntactic aspects of the information market. We explore the information landscape using a modeling approach. An important part of this model is a (syntactic) framework for transformations, which allows us to deal with the heterogeneity of the data resources found on the Web. Last but not least, we attempt to give an outline how our model may lead to a better understanding of how information is supplied via the Web. For this we use an example from the field of information retrieval.
Interleukin-1β is the primary initiator of pulmonary inflammation following liver injury in mice
Authors: Glasgow Sean C. , Ramachandran Sabarinathan , Blackwell Timothy S. , Mohanakumar T. , Chapman William C.
Published: June 2007

Hepatic injury can lead to systemic and pulmonary inflammation through activation of NF-κB-dependent pathways and production of various proinflammatory cytokines. The exact mechanism remains unknown, although prior research suggests interleukin-1β (IL-1β) plays an integral role. Cultured murine alveolar macrophages were used to identify an optimized IL-1β-specific short interfering RNA (siRNA) sequence, which then was encapsulated in liposomes and administered intraperitoneally to transgenic HLL mice (5′-HIV-LTR-Luciferase). A 35% hepatic mass cryoablation in HLL and IL-1 receptor 1 knockout mice (IL1R1KO) was performed as a model for liver-induced pulmonary inflammation. IL-1β siRNA pretreatment effectively and significantly reduced circulating IL-1β levels at 4 h post-hepatic injury. IL-6 also was suppressed in mice with impaired IL-1 signaling pathways. NF-κB activation in the noninjured liver of HLL reporter mice pretreated with IL-1β siRNA was found to be reduced compared with controls. Pulmonary NF-κB activity in this group also was diminished relative to controls. C-X-C chemokine levels in the lung remained significantly lower in IL-1 pathway-deficient mice. Similarly, lung myeloperoxidase content was unchanged from baseline at 24 h post-liver injury in IL-1β siRNA-treated animals, whereas all other control groups demonstrated marked pulmonary neutrophilic infiltration. In conclusion, liver injury-induced lung inflammation in this model is mediated predominantly by IL-1β. Knockdown of IL-1β expression before hepatic injury led to significant reductions in both cytokine production and NF-κB activation. This translated to reduced pulmonary neutrophil accumulation. Pretreatment with IL-1β siRNA may represent a novel intervention for preventing liver-mediated pulmonary inflammation.
Genetic Variation in H2AFX Contributes to Risk of Non–Hodgkin Lymphoma
Authors: Novik Karen L. , Spinelli John J. , MacArthur Amy C. , Shumansky Karey , Sipahimalani Payal , Leach Stephen , Lai Agnes , Connors Joseph M. , Gascoyne Randy D. , Gallagher Richard P. , Brooks-Wilson Angela R.
Published: June 2007

Non–Hodgkin lymphoma (NHL) comprises a group of lymphoid tumors that have in common somatic translocations. H2AFX encodes a key histone involved in the detection of the DNA double-stranded breaks that can lead to translocations. H2afx is a dosage-dependent gene that protects against B-cell lymphomas in mice, making its human orthologue an ideal candidate gene for susceptibility to lymphoma. We did a population-based genetic association study of H2AFX variants in 487 NHL cases and 531 controls. Complete resequencing of the human H2AFX gene in 95 NHL cases was done to establish the spectrum of variation in affected individuals; this was followed by both direct and indirect tests for association at the level of individual single nucleotide polymorphisms (SNP) and as haplotypes. Homozygosity for the AA genotype of a SNP 417 bp upstream of the translational start of H2AFX is strongly associated [odds ratio (OR), 0.54; P = 0.001] with protection from NHL. We find a strong association of this SNP with the follicular lymphoma subtype of NHL (AA genotype: OR, 0.40; P = 0.004) and with mantle cell lymphoma (AA genotype: OR, 0.20; P = 0.01) that remains significant after adjustment for the false discovery rate, but not with diffuse large B-cell lymphoma. These data support the hypothesis that genetic variation in the H2AFX gene influences genetic susceptibility or resistance to some subtypes of NHL by contributing to the maintenance of genome stability. (Cancer Epidemiol Biomarkers Prev 2007;16(6):1098–106)
Associations between Smoking, Polymorphisms in Polycyclic Aromatic Hydrocarbon (PAH) Metabolism and Conjugation Genes and PAH-DNA Adducts in Prostate Tumors Differ by Race
Authors: Nock Nora L. , Tang Deliang , Rundle Andrew , Neslund-Dudas Christine , Savera Adnan T. , Bock Cathryn H. , Monaghan Kristin G. , Koprowski Allison , Mitrache Nicoleta , Yang James J. , Rybicki Benjamin A.
Published: June 2007

Polycyclic aromatic hydrocarbon (PAH)-DNA adducts may induce mutations that contribute to carcinogenesis. We evaluated potential associations between smoking and polymorphisms in PAH metabolism [CYP1A1 Ile462Val, CYP1B1 Ala119Ser and Leu432Val, microsomal epoxide hydrolase (mEH) Tyr113His and His139Arg, CYP3A4 A(−392)G] and conjugation [glutathione S-transferase (GST) M1 null deletion, GSTP1 Ile105Val] genes and PAH-DNA adduct levels (measured by immunohistochemistry) in tumor and nontumor prostate cells in 400 prostate cancer cases. Although no statistically significant associations were observed in the total sample, stratification by ethnicity revealed that Caucasian ever smokers compared with nonsmokers had higher adduct levels in tumor cells (mean staining intensity in absorbance units ± SE, 0.1748 ± 0.0052 versus 0.1507 ± 0.0070; P = 0.006), and Caucasians carrying two mEH 139Arg compared with two 139His alleles had lower adducts in tumor (0.1320 ± 0.0129 versus 0.1714 ± 0.0059; P = 0.006) and nontumor (0.1856 ± 0.0184 versus 0.2291 ± 0.0085; P = 0.03) cells. African Americans with two CYP1B1 432Val compared with two 432Ile alleles had lower adducts in tumor cells (0.1600 ± 0.0060 versus 0.1970 ± 0.0153; P = 0.03). After adjusting for smoking status, carrying the putative “high-risk” genotype combination, the faster metabolism of PAH-epoxides to PAH-diol-epoxides (CYP1B1 432Val/Val and mEH 139Arg/Arg) with lower PAH-diol-epoxide conjugation (GSTP1 105Ile/Ile), was associated with increased adducts only in Caucasian nontumor cells (0.2363 ± 0.0132 versus 0.1920 ± 0.0157; P= 0.05). We present evidence, for the first time in human prostate that the association between smoking and PAH-DNA adducts differs by race and is modified by common genetic variants. (Cancer Epidemiol Biomarkers Prev 2007;16(6):1236–45)
Triallelic Single Nucleotide Polymorphisms and Genotyping Error in Genetic Epidemiology Studies:MDR1(ABCB1)G2677/T/Aas an Example
Authors: Hüebner Claudia , Petermann Ivonne , Browning Brian L. , Shelling Andrew N. , Ferguson Lynnette R.
Published: June 2007

Accurate measurement of allele frequencies between population groups with differing sensitivities to disease is fundamental to genetic epidemiology. Genotyping errors can markedly influence the biological conclusions of a study. This issue may be especially important now there is increasing recognition of triallelic single nucleotide polymorphisms (SNPs) in the genome and their possible role in diseases like inflammatory bowel disease. For example, the MDR1 (ABCB1) SNP G2677/T/A was, like many other triallelic SNPs, originally described as diallelic. Here, we report a comprehensive analyses of estimated allele frequencies of this SNP in a set of 73 human DNA samples, comparing six commonly used genotyping methods (Applied Biosystems Taqman, Roche LightCycler melting analysis, allelic discrimination PCR, DNA sequencing, Sequenom, and RFLP) from the angle of their error potential. Only Sequenom and DNA sequencing provided accurate measurements, if we had not had prior knowledge of the triallelic nature of this SNP. The other tested methods (with the exception of LightCycler) failed to show any indication of the presence of the rare third A- allele in a diallelic assay. Although most of the errors were due to the inability to detect the third allele, all methods except Sequenom and sequencing produced errors for the detection of the two common alleles G and T (LightCycler, 6 errors; PCR, 4 errors; RFLP, 2 errors; Taqman, 1 error). There is considerable variability in the reported frequencies of the different alleles of the MDR1 G2677/T/A SNP, and the role of this SNP in the etiology of inflammatory bowel disease has been controversial. Our data emphasize the importance of choosing the appropriate method for SNP detection and lead us to suggest that part of the previously reported variation may reflect artifacts associated with the different genotyping methodologies used. The failure to recognize the triallic nature of a SNP may lead to underestimations of real genetic associations. (Cancer Epidemiol Biomarkers Prev 2007;16(6):1185–92)
The Cigarette Controversy
Authors: Cummings K. Michael , Brown Anthony , O'Connor Richard
Published: June 2007

This study examines the history of the cigarette controversy using the tobacco documents as a roadmap to explore the following four questions: (a) What did tobacco companies know about the health risks of smoking and when did they know it? (b) What evidence is there that tobacco companies conspired to deliberately mislead the public about the health risks of smoking? (c) How were scientists involved in the cigarette controversy? (d) Have tobacco companies changed the way they do business since signing the 1998 Master Settlement Agreement? The tobacco companies knew and for most part accepted the evidence that cigarette smoking was a cause of cancer by the late 1950s. The documents also reveal that the tobacco companies helped manufacture the smoking controversy by funding scientific research that was intended to obfuscate and prolong the debate about smoking and health. Today, the tobacco companies acknowledge that smoking is a cause of disease, but they have not materially altered the way they do business. In our opinion, it is not sufficient for the tobacco industry to merely concede the obvious point that smoking is a cause of disease when it is evident that decades of misinformation has resulted in a public that is massively ignorant about the risks of smoking low-tar cigarettes, nicotine addiction, and secondhand smoke exposure. Public education efforts are still needed to correct these misperceptions along with government oversight to ensure that the industry is not permitted to mislead the public further. If the past 50 years have taught us anything, it is that the tobacco industry cannot be trusted to put the public's interest above their profits no matter what they say. (Cancer Epidemiol Biomarkers Prev 2007;16(6):1070–6)
Intermediate Outcomes from Project MYTRI: Mobilizing Youth for Tobacco-Related Initiatives in India
Authors: Stigler Melissa H. , Perry Cheryl L. , Arora Monika , Shrivastav Radhika , Mathur Charu , Reddy K. Srinath
Published: June 2007

The purpose of this article is to present the intermediate results for Project MYTRI, a school-based, multiple component intervention designed to prevent and reduce many forms of tobacco use (chewing tobacco, cigarettes, and bidis) among youth in India. The intervention is based on effective models in the United States “translated” for use in this context. The intervention targets two cohorts of students who were in the 6th and 8th grade when the study started. Thirty-two schools in Delhi (north India) and Chennai (south India) were randomized to receive the intervention (n = 16) or serve as a delayed intervention control (n = 16). Students in these schools were surveyed before the intervention began and at an intermediate point, 1 year into this 2-year intervention (n = 8,369). A test of the changes in risk factors for tobacco use between the baseline and intermediate surveys revealed that, compared with the control, students in the intervention condition (a) had better knowledge about the health effects of tobacco (P < 0.01); (b) believed that there were more negative social consequences to using tobacco (P = 0.04); (c) had fewer reasons to use tobacco (P < 0.01); (d) had more reasons not to use tobacco (P = 0.03); (e) were less socially susceptible to chewing (P = 0.04) and smoking (P = 0.03) tobacco; (f) perceived fewer peers and adults around them smoked (P < 0.01) or chewed (P < 0.01) tobacco; (g) felt that tobacco use was not acceptable, especially among their peers (P < 0.01); (h) were more confident in their ability to advocate for tobacco control (P = 0.03); (i) were more knowledgeable about tobacco control policies (P < 0.01); and (j) supported these policies, too (P = 0.04). Fewer students in the intervention condition reported having intentions to smoke tobacco in the next year (P = 0.02) or chew tobacco when they reached college (P < 0.01). No changes in actual tobacco use were observed at this stage of the study. (Cancer Epidemiol Biomarkers Prev 2007;16(6):1050–6)