bluuebunny/crossref_metadata_2025 huggingface dataset:
Formal and informal dimensions of intergovernmental administrative relations in Canada
Authors: Johns Carolyn M. , O'Reilly Patricia L. , Inwood Gregory J.
Published: January 2008

Abstract: The past two decades have witnessed significant changes in Canadian federalism and intergovernmental relations. This article investigates how developments in federalism and public administration in the 1990s have affected intergovernmental administrative machinery and the formal and informal structures, functions, and resources of intergovernmental relations compared to findings from the 1980s. Using a survey, interviews with senior intergovernmental officials, and government documents, this paper examines the evolution of the intergovernmental administrative state as opposed to the political realm of executive federalism. The authors outline how the formal structures and functions of intergovernmental agencies and officials have evolved and argue that informal intergovernmental networks are very important in understanding and explaining the capacity of the federation to meet current and future policy and administrative challenges.

Sommaire: Au cours des deux dernières décennies, d'importants changements se sont produits au sein du fédéralisme et des relations intergouvernementales au Canada. Le présent article examine comment les récents développements intervenus dans le fédéralisme et l'administration publique dans les années 1990 ont affecté les rouages administratifs intergouvernementaux et les structures officielles et non officielles, ainsi que les fonctions et ressources des relations intergouvernementales au cours de deux dernièves décennies comparativement aux résultats des années 1980. A l'aide d'un sondage, d'interviews de hauts fonctionnaires intergouvernementaux et de documents gouvernementaux, cet article étudie l'évolution de l'État administratif intergouvernemental par opposition au domaine politique du fédéralisme exécutif. Les auteurs ébauchent la façon dont les structures et les fonctions officielles des organismes et des hauts fonctionnaires intergouvernementaux ont évolué et soutiennent que les réseaux intergouvernementaux non officiels sont très importants pour comprendre et expliquer l'aptitude de la fédération à relever les défis politiques et administratifs présents et futurs.
Les gestionnaires de l'ombre: les directeurs1 de cabinets ministériels québécois
Authors: Maltais Daniel , Harvey Marie‐Eve
Published: January 2008

Sommaire: La proximité du ministre pour les directeurs de cabinet ministériel, leur accès à des informations stratégiques et sensibles et leur possibilité d'influencer le ministre ainsi que les hauts fonctionnaires sur des décisions de nature politique ou administrative, sont parmi les facteurs qui expliquent l'importance des rôles qu'ils peuvent jouer dans la gestion des ministères et organismes gouvernementaux. Pourtant, on trouve relativement peu d'écrits sur le sujet et les études sur le personnel politique datent de plusieurs années. À partir d'une enquête et d'entrevues réalisées avec des directeurs de cabinet du gouvernement du Québec ainsi qu'avec des sousministres, cette étude trace un portrait des principales caractéristiques des directeurs de cabinet ministériel. Elle examine la façon dont ils assument leurs fonctions et la nature des relations qu'ils entretiennent avec le ministre, le personnel du cabinet qu'ils dirigent et l'administration.

Abstract: Proximity to the minister, access to strategic and sensitive information, and the ability to influence the minister and senior public servants in decision‐making are among the factors that explain the importance of the role of chief of staff to the minister in the management of ministries and government organizations. The literature on the subject, however, is relatively limited, and available studies on political staff are several years old. Based on a survey and interviews with chiefs of staff and deputy ministers in the Quebec government, this study describes the main characteristics of chiefs of staff. It examines the way they carry out their functions and the nature of the relationships they have with the minister and the staff that they manage.
Making the least of our differences? Trends in local economic development in Ontario and Michigan, 1990–2005
Authors: Reese Laura A. , Sands Gary
Published: January 2008

Abstract: This paper examines trends in local economic development policies in Canadian and US cities over the past fifteen years. Using data drawn from surveys conducted at four points in time ‐ 1990, 1994, 2001, and 2005 ‐ the study provides a longitudinal assessment of change versus stability in overall approach toward economic development. Findings indicate that Canadian and US cities have followed relatively similar trajectories in the extent to which they use particular economic development policies. Overall, the most common economic development policies in both nations have been and continue to be very similar: infrastructure investment generally, land development, basic promotion, and the use of special events to attract and retain businesses and residents and to promote the community. Thus, there is a visible pattern of the “least of differences” among cities in Michigan and Ontario in their development strategies and approaches.

Sommaire: Le présent article examine les tendances qui se sont dégagées des politiques de développement économique local dans les villes canadiennes et américaines, au cours des quinze dernières années. À l'aide des données tirées de sondages réalisés à quatre moments différents, à savoir en 1990, 1994, 2001 et 2005, l‘étude fournit une évaluation longitudinale des changements par rapport à la stabilité dans l'approche globale à l’égard du développement économique. Les résultats indiquent que les villes canadiennes et américaines ont suivi des trajectoires relativement similaires dans la mesure où elles ont recours à des politiques de développement économique particulières. Dans l'ensemble, les politiques de développement économique les plus courantes dans ces deux pays ont été et continuent d‘être très similaires: l'investissement dans l'infrastructure en général, l'aménagement du territoire, la promotion de base, et le recours à des événements spéciaux pour attirer et retenir les entreprises et les résidents et pour promouvoir la communauté. Ainsi, il existe parmi certaines villes du Michigan et de l'Ontario un modèle visible de la “moindre des différences” dans leurs stratégies et leurs méthodes de développement.
Responding to the global tobacco industry: Canada and the Framework Convention on Tobacco Control
Authors: Lavack Anne M. , Clark Gina
Published: January 2008

Abstract: In a continuing quest to build and defend world markets for tobacco products, tobacco companies have long been involved in international cooperation and information‐sharing through their own international corporate networks, as well as through national and international industry trade associations. This is evidenced in tobacco industry corporate documents now freely available on the internet. In order to institute effective tobacco control policy, policy‐makers needed to become equally astute at sharing information across national boundaries and at considering the cross‐national implications of policy and legislation. The World Health Organization has been instrumental in developing the Framework Convention on Tobacco Control (FCTC), and Canada has played an important part in this effort. The FCTC contains both demand‐reduction provisions and supply‐side provisions intended to reduce tobacco use worldwide. As a signatory to the FCTC, Canada has pledged to adhere to these provisions, thereby providing Canadian public administrators with effective tools to reduce tobacco use and its associated health burden both nationally and internationally.

Sommaire: En cherchant continuellement à développer et à défendre les marchés mondiaux pour les produits du tabac, les sociétés productrices de tabac sont impliquées depuis longtemps dans la coopération internationale et le partage d'informations par le biais de leurs propres réseaux de sociétés internationales et d'associations professionnelles nationales et internationales. C'est ce qui ressort des documents des sociétés productrices de tabac auxquels on peut accéder librement sur Internet. Afin d'instituer une politique efficace de contrôle du tabagisme, les décideurs politiques ont dù devenir astucieux quant au partage d'informations et à l'étude des répercussions transnationales des politiques et des lois. L'Organisation mondiale de la santé a fortement contribuéà l'élaboration de la Convention‐cadre sur la lutte contre le tabagisme (CCLCT), et le Canada a joué un rôle important sur ce plan. La CCLCT contient à la fois des dispositions relatives à la réduction de la demande et d'autres relatives à l'offre qui visent à réduire la consommation de tabac dans le monde entier. En tant que pays signataire de la CCLCT, le Canada s'est engagéà respecter ces dispositions, fournissant ainsi aux administrateurs publics canadiens des outils efficaces pour réduire la consommation de tabac et le fardeau sur la santé qui lui est associéà l'échelle nationale et internationale.
Ministerial responsibility and the machinery of government
Authors: D'Ombrain Nicholas
Published: January 2008

Abstract: This article examines the relationship between ministerial responsibility and the machinery of government. It discusses how constitutional government and the practical day‐to‐day functioning of a parliamentary democracy depend on ministerial responsibility as the bedrock principle for the organization and operation of the machinery of government across the range of government organizations. It concludes that ministerial responsibility remains the pivotal constitutional doctrine essential to the functioning of a parliamentary democracy; that notwithstanding the undue concentration of authority in the hands of first ministers, their machinery of government powers ought not to be reduced; and that first ministers in particular should pay closer attention to ministerial responsibility as the foundation of the machinery of government.

Sommaire: Le présent article porte sur les relations entre la responsabilité ministéri‐elle et l'appareil gouvernemental. Il examine comment le gouvernement constitutionnel et le fonctionnement pratique quotidien d'une démocratie parlementaire reposent sur la responsabilité ministérielle comme principe de base de l'organisation et du fonctionnement de l'appareil gouvernemental dans tous les types d'organismes gouvernementaux. L'auteur conclut que la responsabilité ministérielle demeure la doctrine constitutionnelle cruciale et essentielle au fonctionnement d'une démocratie parlementaire; que malgré la concentration exagérée de pouvoir entre les mains des premiers ministres, les pouvoirs de l'appareil gouvernemental ne devraient pas être réduits; et que les premiers ministres en particulier devraient prêter une plus grande attention à la responsabilité ministérielle en tant que fondement de l'appareil gouvernemental.
Design of a Phase Separation System for a Direct Steam Generation Parabolic Trough Collector Field
Authors: Hirsch Tobias , Eck Markus
Published: January 2008

The dynamic behavior of a parabolic trough collector field with direct steam generation under varying solar conditions is analyzed using a transient simulation model. It is found that the peak water flow rates observed during transients may reach several times the steady-state design values. Taking into account these results, a method is developed for calculating the required separation efficiency of the water-steam separator between evaporating and superheating sections of the solar field. For a field with individual phase separators arranged in each collector row, the drainage system, used for transporting the separated water from the field to a central buffer tank, is dimensionally defined. It turns out that a buffer capacity of about 0.1m3 and a large-diameter drainage line have to be foreseen in order to cope with the high liquid loads under solar transients. The results are compared to a field layout with one central separation drum in terms of materials consumption and thermal inertia. It turns out that the originally intended effect of a reduced thermal inertia is not reached when transient conditions are taken care of in the design of the components.
Solid Media Thermal Storage Development and Analysis of Modular Storage Operation Concepts for Parabolic Trough Power Plants
Authors: Laing Doerte , Steinmann Wolf-Dieter , Fiß Michael , Tamme Rainer , Brand Thomas , Bahl Carsten
Published: January 2008

Cost-effective integrated storage systems are important components for the accelerated market penetration of solarthermal power plants. Besides extended utilization of the power block, the main benefits of storage systems are improved efficiency of components, and facilitated integration into the electrical grids. For parabolic trough power plants using synthetic oil as the heat transfer medium, the application of solid media sensible heat storage is an attractive option in terms of investment and maintenance costs. For commercial oil trough technology, a solid media sensible heat storage system was developed and tested. One focus of the project was the cost reduction of the heat exchanger; the second focus lies in the energetic and exergetic analysis of modular storage operation concepts, including a cost assessment of these concepts. The results show that technically there are various interesting ways to improve storage performance. However, these efforts do not improve the economical aspect. Therefore, the tube register with straight parallel tubes without additional structures to enhance heat transfer has been identified as the best option concerning manufacturing aspects and investment costs. The results of the energetic and exergetic analysis of modular storage integration and operation concepts show a significant potential for economic optimization. An increase of more than 100% in storage capacity or a reduction of more than a factor of 2 in storage size and therefore investment cost for the storage system was calculated. A complete economical analysis, including the additional costs for this concept on the solar field piping and control, still has to be performed.
Optical Performance and Weight Estimation of a Heliostat With Ganged Facets
Authors: Amsbeck L. , Buck R. , Pfahl A. , Uhlig R.
Published: January 2008

In standard heliostat design, the usual strategy of cost reduction is to increase the mirror area of the heliostats. This not only leads to a reduction of specific drive cost but also to an increase of the torques caused by the wind loads, resulting in higher specific weight and higher specific drive power. These drawbacks are avoided when small heliostats are coupled. At the torque tube heliostat (TTH), the mirrors are mounted on torque tubes to simplify the coupling mechanism for the elevation angle. Ray tracing calculations were done to obtain optimized heliostat configurations and to compare the energy yield of a heliostat field built of 288m2 TTHs with a conventional heliostat field. To get an idea of the weight reduction potential of the TTH, the dimensions of the torque tubes, the secondary axis tubes, and the mirror support structure were weight optimized via finite element method. The layout criterion was a mean mirror error of 2.5mrads under wind load and gravity.
Iron-Containing Yttria-Stabilized Zirconia System For Two-Step Thermochemical Water Splitting
Authors: Gokon Nobuyuki , Mizuno Takayuki , Nakamuro Yumiko , Kodama Tatsuya
Published: January 2008

An iron-containing yttria-stabilized zirconia (YSZ) or Fe-YSZ was found to be a promising working redox material for the thermochemical two-step water-splitting cycle. The Fe-YSZ was formed by a high-temperature reaction between YSZ doped with more than 8mol%Y2O3 and Fe3O4 supported on the YSZ at 1400°C in an inert atmosphere. The formed Fe-YSZ reacted with steam to generate hydrogen at 1000°C. The oxidized Fe-YSZ was reactivated by a thermal reduction at 1400°C in an inert atmosphere. The alternative O2 and H2 generations in the repeated two-step reactions and the X-ray diffraction and chemical analysis studies on the solid materials indicated that the two-step water splitting was associated with a redox transition between Fe2+–Fe3+ ions in the cubic YSZ lattice.
Solar Field Efficiency and Electricity Generation Estimations for a Hybrid Solar Gas Turbine Project in France
Authors: Garcia Pierre , Ferriere Alain , Flamant Gilles , Costerg Philippe , Soler Robert , Gagnepain Bruno
Published: January 2008

The production of electricity with gas turbine and solar energy project aims to install at the Themis site (Targasonne, France) a prototype of hybrid solar/fossil gas-turbine system for electricity generation. The system features a 3800kWth pressurized air solar receiver combined with a fossil backup feeding a recuperated 1400kWe Turbomeca gas turbine with an external combustion chamber.
Experimental validation of band gaps and localization in a one-dimensional diatomic phononic crystal
Authors: Hladky-Hennion Anne-Christine , Billy Michel de
Published: January 2008

The propagation of compressional ultrasonic pulses through a finite one-dimensional chain of various unit cells is investigated experimentally. The chain, initially compressed by an axially applied constant force, is excited by a periodic force, which acts in line with axis of bead chain. The experimental measurements giving the eigenfrequencies of the specimen are based on a Fourier analysis of the transmitted acoustic pulse. The results are compared with the numerical calculations and it is shown that the two approaches are well correlated. A phononic band structure is observed and under certain conditions, depending on the parity of the number and on the masses of the beads in the chain, it is shown that localized modes propagating in the forbidden band are exhibited. Much attention is devoted to the existence of these localized modes according to the mass ratio between two adjacent beads constituting the unit cell.
A high-frequency warm shallow water acoustic communications channel model and measurements
Authors: Chitre Mandar
Published: January 2008

Underwater acoustic communication is a core enabling technology with applications in ocean monitoring using remote sensors and autonomous underwater vehicles. One of the more challenging underwater acoustic communication channels is the medium-range very shallow warm-water channel, common in tropical coastal regions. This channel exhibits two key features—extensive time-varying multipath and high levels of non-Gaussian ambient noise due to snapping shrimp—both of which limit the performance of traditional communication techniques. A good understanding of the communications channel is key to the design of communication systems. It aids in the development of signal processing techniques as well as in the testing of the techniques via simulation. In this article, a physics-based channel model for the very shallow warm-water acoustic channel at high frequencies is developed, which are of interest to medium-range communication system developers. The model is based on ray acoustics and includes time-varying statistical effects as well as non-Gaussian ambient noise statistics observed during channel studies. The model is calibrated and its accuracy validated using measurements made at sea.
Statistical estimation of transmission loss from geoacoustic inversion using a towed array
Authors: Goh Yong Han , Gerstoft Peter , Hodgkiss William S. , Huang Chen-Fen
Published: January 2008

Geoacoustic inversion estimates environmental parameters from measured acoustic fields (e.g., received on a towed array). The inversion results have some uncertainty due to noise in the data and modeling errors. Based on the posterior probability density of environmental parameters obtained from inversion, a statistical estimation of transmission loss (TL) can be performed and a credibility level envelope or uncertainty band for the TL generated. This uncertainty band accounts for the inherent variability of the environment not usually contained in sonar performance prediction model inputs. The approach follows [Gerstoft et al. IEEE J. Ocean. Eng. 31, 299–307 (2006)] and is demonstrated with data obtained from the MAPEX2000 experiment conducted by the NATO Undersea Research Center using a towed array and a moored source in the Mediterranean Sea in November 2000. Based on the geoacoustic inversion results, the TL and its variability are estimated and compared with the measured TL.
The social vocalization repertoire of east Australian migrating humpback whales (Megaptera novaeangliae)
Authors: Dunlop Rebecca A. , Noad Michael J. , Cato Douglas H. , Stokes Dale
Published: January 2008

Although the songs of humpback whales have been extensively studied, other vocalizations and percussive sounds, referred to as “social sounds,” have received little attention. This study presents the social vocalization repertoire of migrating east Australian humpback whales from a sample of 660 sounds recorded from 61 groups of varying composition, over three years. The social vocalization repertoire of humpback whales was much larger than previously described with a total of 34 separate call types classified aurally and by spectrographic analysis as well as statistically. Of these, 21 call types were the same as units of the song current at the time of recording but used individually instead of as part of the song sequence, while the other 13 calls were stable over the three years of the study and were not part of the song. This study provides a catalog of sounds that can be used as a basis for future studies. It is an essential first step in determining the function, contextual use and cultural transmission of humpback social vocalizations.
Small-slope simulation of acoustic backscatter from a physical model of an elastic ocean bottom
Authors: Soukup Raymond J. , Canepa Gaetano , Simpson Harry J. , Summers Jason E. , Gragg Robert F.
Published: January 2008

An underwater acoustic experiment with a two-dimensional rough interface, milled from a slab of PVC, was performed at a tank facility. The purpose was to verify the predictions of numerical models of acoustic rough surface scattering, using a manufactured physical model of an ocean bottom that featured shear effects, nonhomogeneous roughness statistics, and root-mean-square roughness amplitude on the order of the acoustic wavelength. Predictions of the received time series and interface scattering strength in the 100–300kHz band were obtained from the Bottom Reverberation from Inhomogeneities and Surfaces–Small-Slope Approximation (BORIS-SSA) numerical scattering model. The predictions were made using direct measurements of scattering model inputs—specifically, the geoacoustic properties from laboratory analysis of material samples and the grid of surface heights from a touch-trigger probe. BORIS-SSA predictions for the amplitude of the received time series were shown to be accurate with a root-mean-square residual error of about 1dB, while errors for the scattering strength prediction were higher (2–3.5dB). The work is part of an ongoing effort to use physical models to examine a variety of acoustic scattering and propagation phenomena involving the ocean bottom.
Noise control in enclosures: Modeling and experiments with T-shaped acoustic resonators
Authors: Li D. , Cheng L. , Yu G. H. , Vipperman J. S.
Published: January 2008

This paper presents a theoretical and experimental study of noise control in enclosures using a T-shaped acoustic resonator array. A general model with multiple resonators is developed to predict the acoustic performance of small resonators placed in an acoustic enclosure. Analytical solutions for the sound pressure inside the enclosure and the volume velocity source strength out of the resonator aperture are derived when a single resonator is installed, which provides insight into the physics of acoustic interaction between the enclosure and the resonator. Based on the understanding of the coupling between the individual resonators and enclosure modes, both targeted and nontargeted, a sequential design methodology is proposed for noise control in the enclosure using an array of acoustic resonators. Design examples are given to illustrate the control performance at a specific or at several resonance peaks within a frequency band of interest. Experiments are conducted to systematically validate the theory and the design method. The agreement between the theoretical and experimental results shows that, with the help of the presented theory and design methodology, either single or multiple resonance peaks of the enclosure can be successfully controlled using an optimally located acoustic resonator array.
A state space model for cochlear mechanics
Authors: Elliott Stephen J. , Ku Emery M. , Lineton Ben
Published: January 2008

The stability of a linear model of the active cochlea is difficult to determine from its calculated frequency response alone. A state space model of the cochlea is presented, which includes a discretized set of general micromechanical elements coupled via the cochlear fluid. The stability of this time domain model can be easily determined in the linear case, and the same framework used to simulate the time domain response of nonlinear models. Examples of stable and unstable behavior are illustrated using the active micromechanical model of Neely and Kim. The stability of this active cochlea is extremely sensitive to abrupt spatial inhomogeneities, while smoother inhomogeneities are less likely to cause instability. The model is a convenient tool for investigating the presence of instabilities due to random spatial inhomogeneities. The number of unstable poles is found to rise sharply with the relative amplitude of the inhomogeneities up to a few percent, but to be significantly reduced if the spatial variation is smoothed. In a saturating nonlinear model, such instabilities generate limit cycles that are thought to produce spontaneous otoacoustic emissions. An illustrative time domain simulation is presented, which shows how an unstable model evolves into a limit cycle, distributed along the cochlea.
Elastic characterization of closed cell foams from impedance tube absorption tests
Authors: Chevillotte F. , Panneton R.
Published: January 2008

A method is presented to determine the bulk elastic properties of isotropic elastic closed-cell foams from impedance tube sound absorption tests. For such foams, a resonant sound absorption is generally observed, where acoustic energy is transformed into mechanical vibration, which in turn is dissipated into heat due to structural damping. This article shows how the bulk Young’s modulus, Poisson’s ratio, and damping loss factor can be deduced from the resonant absorption. Also, an optimal damping loss factor yielding 100% of absorption at the first resonance is defined from the developed theory. The method is introduced for a sliding edge condition which is an ideal condition. Then, the method is extended to a bonded edge condition which is more easily achievable and additionally enables the identification of the Poisson’s ratio. The method is experimentally tested on expanding closed-cell foams to find their elastic properties in both cases. Using the found properties, sound absorption predictions using an equivalent solid model with and without surface absorption are compared to measurements. Good correlations are obtained when considering surface absorption.
A detailed study on the effects of noise on speech intelligibility
Authors: Dubbelboer Finn , Houtgast Tammo
Published: January 2008

A wavelet representation of speech was used to display the instantaneous amplitude and phase within 1∕4 octave frequency bands, representing the envelope and the carrier within each band. Adding stationary noise alters the wavelet pattern, which can be understood as a combination of three simultaneously occurring subeffects: two effects on the wavelet levels (one systematic and one stochastic) and one effect on the wavelet phases. Specific types of signal processing were applied to speech, which allowed each effect to be either included or excluded. The impact of each effect (and of combinations) on speech intelligibility was measured with CVC’s. It appeared that the systematic level effect (i.e., the increase of each speech wavelet intensity with the mean noise intensity) has the most degrading effect on speech intelligibility, which is in accordance with measures such as the modulation transfer function and the speech transmission index. However, also the introduction of stochastic level fluctuations and disturbance of the carrier phase seriously contribute to reduced intelligibility in noise. It is argued that these stochastic effects are responsible for the limited success of spectral subtraction as a means to improve speech intelligibility. Results can provide clues for effective noise suppression with respect to intelligibility.
Vortex sound under the influence of a piecewise porous material on an infinite rigid plane
Authors: Lau C. K. , Tang S. K.
Published: January 2008

The vortex dynamics and the sound generation by an inviscid vortex in the presence of a finite length porous material on an otherwise rigid plane are studied numerically in the present study in an attempt to understand the sound generation near the surface of a wall lining in a lined duct. The combined effects of the effective fluid density and flow resistance inside the porous material, and the length and thickness of the porous material on the sound generation process are examined in detail. Results obtained demonstrate the sound pressure is longitudinal dipole and show how seriously the above-mentioned parameters are affecting the vortex sound pressure under the influence of the porous material.
Accurate vocal compensation for sound intensity loss with increasing distance in natural environments
Authors: Zahorik Pavel , Kelly Jonathan W.
Published: January 2008

Human abilities to adjust vocal output to compensate for intensity losses due to sound propagation over distance were investigated. Ten normally hearing adult participants were able to compensate for propagation losses ranging from −1.8 to −6.4dB∕doubling source distance over a range of distances from 1 to 8m. The compensation was performed to within 1.2dB of accuracy on average across all participants, distances, and propagation loss conditions with no practice or explicit training. These results suggest that natural vocal communication processes of humans may incorporate tacit knowledge of physical sound propagation properties more sophisticated than previously supposed.
Experimental study of surface wave propagation in strongly heterogeneous media
Authors: Aggelis Dimitrios G. , Shiotani Tomoki
Published: January 2008

In the present paper, the propagation of Rayleigh waves in a strongly heterogeneous medium is discussed. Scattering of stress waves is a difficult scientific problem. Specifically, the interaction of surface waves with distributed inhomogeneity seems highly complicated due to the existence of two displacement components. Rayleigh waves undergo significant attenuation and velocity change depending on the frequency and the inhomogeneity content. The aim of this study is to highlight the dispersive behavior of concrete, especially when damaged, and increase the experimental data in an area where the work is limited.
Array gain for a cylindrical array with baffle scatter effects
Authors: Bertilone Derek C. , Killeen Damien S. , Bao Chaoying
Published: January 2008

Cylindrical arrays used in sonar for passive underwater surveillance often have sensors surrounding a cylindrical metal baffle. In some operational sonars, the phones in each stave (i.e., each line of phones aligned with the cylinder axis) are hardwired together so that the array is equivalent to a baffled circular array of directional elements, where each element corresponds to a line array of omnidirectional phones steered to broadside. In this paper a model is introduced for computing the array gain of such an array at high frequencies, which incorporates baffle scatter using infinite, rigid cylinder scattering theory, and with ambient noise described by an angular spectral density function. In practice the phones are often offset from the baffle surface, and the acoustic field sampled by the staves is distorted at high frequencies due to interference between the incident and scattered fields. Examples are given to illustrate the resulting array gain degradation, using three noise distributions that are frequently used in sonar performance modeling: three-dimensional isotropic, two-dimensional isotropic, and surface dipole noise.
Estimation of tissue’s elasticity with surface wave speed
Authors: Zhang Xiaoming , Greenleaf James F.
Published: January 2008

The mechanical response of tissues to external forces has gained considerable interest in medical diagnosis. One approach to imaging tissue elastic properties is to apply an external force on the surface of the body. Another approach is to generate a localized force inside the tissue with the radiation force of ultrasound. In this paper, a new method is developed to estimate tissue’s elasticity based on surface wave speed measurement. The theory of surface wave speed is developed for estimating tissue’s elasticity. Experiments are carried out on a tissue-mimicking ultrasound phantom. An amplitude modulated ultrasound signal of a few hundred hertz is used to generate a localized force in the phantom. The surface wave fields are measured with a laser vibrometer. It shows that the surface wave speed can be used for inversely estimating tissue’s elastic properties based on tissue’s surface measurement.
Annoyance due to single and combined sound exposure from railway and road traffic
Authors: Öhrström Evy , Barregård Lars , Andersson Eva , Skånberg Annbritt , Svensson Helena , Ängerheim Pär
Published: January 2008

Environmental noise is a growing and well recognized health problem. However, in many cases people are exposed not to a single noise source—for example, road, railway, or aircraft noise—but to a combination of noise exposures and there is only limited knowledge of the effects on health of exposure to combined noise sources. A socio-acoustic survey among 1953 persons aged 18–75 years was conducted in residential areas exposed to railway and road traffic noise with sound levels ranging from LAeq,24h 45–72dB in a municipality east of Gothenburg, Sweden. The objectives were to assess various adverse health effects, including annoyance, and to elucidate the impact of exposure to single and combined noise sources. In areas exposed to both railway and road traffic, the proportion annoyed by the total traffic sound environment (total annoyance) was significantly higher than in areas with one dominant noise source (rail or road traffic) with the same total sound exposure (LAeq,24h,tot). This interaction effect was significant from 59dB and increased gradually with higher sound levels. Effects of the total sound exposure should be considered in risk assessments and in noise mitigation activities.
Estimated source intensity and active space of the American alligator (Alligator Mississippiensis) vocal display
Authors: Todd Neil P. McAngus
Published: January 2008

In this article the results are reported of a study to measure the intensity of the vocal displays of a population of American alligators (Alligator mississippiensis). It was found that the dominant frequencies in air range between 20 and 250Hz with a source sound pressure level (SPL) of 91–94dB at 1m. The active space for the air-borne component is defined by the background and was estimated to be in a range up to 159m in the 125–200Hz band. For the water-borne component the dominant frequency range was 20–100Hz with a source SPL of 121–125dB at 1m. The active space in water is defined by hearing thresholds and was estimated to range up to 1.5km in the 63–100Hz band. In the lowest frequency bands, i.e., 16–50Hz, the estimated active space for otolith detection of near-field particle motion in water ranged to 80m, which compared significantly with far-field detection for these frequencies. It is suggested that alligator vocal communication may involve two distinct sensory mechanisms which may subserve the functions of scene analysis and reproduction, respectively.
Transfer matrix of conical waveguides with any geometric parameters for increased precision in computer modeling
Authors: Kulik Yakov
Published: January 2008

The existing formula for the transfer matrix of conical elements assumes constant wave number, which is only valid for sufficiently short conical elements. In acoustic waveguides, the phase velocity, attenuation constant, and hence complex wave number depend on frequency and cross-section radius. As for conical waveguides, the cross-section radius is position dependent, the transfer matrix must allow for a position-dependent wave number. Taking this into account, this letter presents an analytic derivation of the transfer matrix for conical waveguides with any geometric parameters, which can be utilized to improve the method of computer modeling of complex waveguides.
A comparative study of whole body vibration training and conventional training on knee proprioception and postural stability after anterior cruciate ligament reconstruction
Authors: Moezy A , Olyaei G , Hadian M , Razi M , Faghihzadeh S
Published: January 2008

Objective:

To compare the effect of a whole body vibration training (WBVT) programme with a conventional training (CT) programme on knee proprioception and postural stability after anterior cruciate ligament (ACL) reconstruction.

Methods:

Twenty athletes with unilateral ACL reconstruction were randomly assigned to the WBVT or CT group; all participants received 12 sessions of WBVT or conventional training. Absolute error in joint repositioning for two target angles (30° and 60°) was measured with the Biodex dynamometer; bilateral dynamic postural stability (anteroposterior, mediolateral and overall stability indices) was measured with the Biodex Stability System pre-intervention and post-intervention.

Results:

The improvement in postural stability in the WBVT group was significantly greater than that in the CT group (p⩽0.05). The p values of the changing scores of open overall, open anteroposterior, open mediolateral, closed overall, closed anteroposterior and closed mediolateral stability indices were 0.002, 0.010, 0.0001, 0.001, 0.0001 and 0.046, respectively. In addition, there were significant differences in all averages of absolute angular error at 60° and 30° between the WBVT and CT groups in both knees (p = 0.001 in healthy knees and p = 0.001 and p = 0.0001 in reconstructed knees), apart from the healthy knees at the 30° target position, which was not significant (p = 0.131).

Conclusions:

Whole body vibration training improved proprioception and balance in athletes with reconstructed ACL.
Consistent individual differences in the foraging behaviour of forest tent caterpillars (Malacosoma disstria)
Authors: Nemiroff L. , Despland E.
Published: January 2008

Outbreaking insects are often considered identical units despite recent work in behavioural ecology that shows repeatable differences can exist between individuals and can have important implications for individual fitness and population processes. However, although entomologists have neglected the hypothesis that differences between individuals can play an important role in the ecology of a species, it is not new. Wellington (1957. Can. J. Zool. 35: 293–323) suggested that consistent individual differences in behaviour may play a role in the population dynamics of Malacosoma (Hübner, 1820) species (Lepidoptera: Lasiocampidae). We used a novel approach to determine if individual larval Malacosoma disstria Hübner, 1820 exhibit distinct and repeatable behavioural traits. Second-instar caterpillars were placed on individual arenas for 1 h on 4 consecutive days, and the proportion of time spent walking, searching, quiescent, and eating was documented. Active and sluggish behavioural types were distinguished and stable differences in individual activity were observed. Activity was positively correlated with growth during the 4 days of the experiment, but no significant relationship was detected between behaviour during the experiment and overall larval performance in the laboratory setting. These findings demonstrate consistent variation in the foraging behaviour of forest tent caterpillars and lay the basis for further investigatison of its role in colony function and population dynamics.
Acoustic monitoring of sixgill shark movements in Puget Sound: evidence for localized movement
Authors: Andrews K.S. , Levin P.S. , Katz S.L. , Farrer D. , Gallucci V.F. , Bargmann G.
Published: January 2008

Understanding the movements of species, particularly those that may exert strong influence on community structure or that may be susceptible to human perturbations, is critical to effectively conserve and manage populations. However, the study of movement behavior in marine fishes has been historically difficult and typically produces a limited amount of data (i.e., start and end points). We use an array of automated acoustic receivers to monitor autumn and winter movement patterns of sixgill sharks ( Hexanchus griseus (Bonnaterre, 1788)) in Puget Sound, Washington, USA. Daily movement of sharks and maximum distance moved from tagging sites varied with size, with larger sharks having shorter daily movements and maximum distances from tagging locations than smaller sharks. Sharks were detected at the same site as the previous day 76% of the time. Movement away from the shark’s tagging location increased slightly over the duration of the study, but most sharks occupied the same sites for most of the study. These relatively small and stable movement patterns could lead to localized, top-down impacts from sixgill sharks and suggest that local human perturbations, such as fishing or pollution, have the potential to negatively affect local populations of sixgill sharks.
Serendipitous discovery of a novel protostrongylid (Nematoda: Metastrongyloidea) in caribou, muskoxen, and moose from high latitudes of North America based on DNA sequence comparisons
Authors: Kutz Susan J. , Asmundsson Ingrid , Hoberg Eric P. , Appleyard Greg D. , Jenkins Emily J. , Beckmen Kimberlee , Branigan Marsha , Butler Lem , Chilton Neil B. , Cooley Dorothy , Elkin Brett , Huby-Chilton Florence , Johnson Deborah , Kuchboev Abdurakhim , Nagy John , Oakley Michelle , Polley Lydden , Popko Richard , Scheer Aedes , Simard Manon , Veitch Alasdair
Published: January 2008

Fecal samples are often the only feasible means to assess diversity of parasites in wildlife; however, definitive identification of egg or larval stages in feces by morphology is rarely possible. We determined partial sequences from the second internal transcribed spacer region (ITS-2) of nuclear ribosomal DNA for first-stage, dorsal-spined larvae (DSL) in feces from caribou ( Rangifer tarandus tarandus (L., 1758), Rangifer tarandus caribou (Gmelin, 1788), Rangifer tarandus grantii (Allen, 1902)), muskoxen ( Ovibos moschatus moschatus (Zimmermann, 1780), Ovibos moschatus wardi Lydekker, 1900), moose ( Alces alces gigas Miller, 1899 and Alces alces andersoni Peterson, 1952), and from the tissue of one slug ( Deroceras laeve (Müller, 1774)) in Arctic–Subarctic North America. A previously uncharacterized, genetically distinct species was recognized based on sequences of 37 DSL from 19 ungulate hosts and the slug. Sequence similarity among individuals of this novel species was 91%–100%. For many individual DSL, paralogues of ITS-2 were detected. ITS-2 sequences from the novel species were 72%–77% similar to those of Varestrongylus alpenae (Dikmans, 1935) and 51%–61% similar to those of other protostrongylids known in North American and some Eurasian ungulates. Results indicate a discrete lineage of an undescribed protostrongylid infecting muskoxen, caribou, and moose from Alaska to Labrador. Sympatric infections with Parelaphostrongylus andersoni Prestwood, 1972 were found in three caribou herds.
RELATIONS BETWEEN NON-ABELIAN CHERN–SIMONS FIELDS AND FRACTIONAL SPINS
Authors: WANG YONG-LONG , XU CHANG-TAN , CHEN LI , JIANG TONG-SONG , CHEN HUAI-TANG
Published: January 2008

In this letter, we briefly recall the quantization of CP4 f1nonlinear σ model coupling with non-Abelian Chern–Simons fields in Faddeev–Senjanovic (FS) path-integral quantization formalism, and discuss the quantum symmetries in this system through the quantum-extended Noether theorem. We obtain interesting and important results, that is the fractional spins of the constrained system are from the orbitally rotational motion of magneton of the non-Abelian Chern–Simons fields, that is, from the interaction between magnetons coupling to the propagator and magnetons coupling to the fixed lattice, with the former orbitally rotating around the latter. This means that anomalous spins are from the interactions among magnetons of Chern–Simons fields.
STRUCTURAL AND OPTICAL PROPERTIES OF POLYCRYSTALLINE6H-SiCAND CRYSTALLINESiCFILM GROWN ONTO SILICON SUBSTRATE BY PLD
Authors: KEFFOUS A. , BOURENANE K. , MANSERI O. , MENARI H. , KEZZOULA F. , KECHOUANE M. , BOURENANE A. , KERDJA T. , NEZZAL G. , BOUKEZZATA A.
Published: January 2008

In this paper, we present a comparative study of structural and optical properties of polycrystalline p-type 6H-SiC and thin SiC layer growth onto Si . The thin SiC layer was grown on a p-type Si(100) substrate by pulsed laser deposition (PLD) using KrF excimer laser from a 6H-SiC hot pressed target. The properties of polycrystalline 6H-SiC and thin SiC layer were investigated by scanning electronic microscopy (SEM), high resolution X-Ray Diffraction (XRD), secondary ion mass spectrometry (SIMS), FT-IR spectroscopy and photoluminescence spectrometry. XRD analysis showed that the two materials have the same hexagonal structure (6H-SiC) as identified by ASTM 72-0018. In addition, a SIMS analysis gives a ratio Si/C of the thin SiC layer around 1.15 but the ratio Si/C of the target was found equal to 1.06, whereas one should have 1.0. This is due to the higher ionization efficiency of Si by the report of C atoms and in photoluminescence, the two materials exhibit the same emission bands (blue and green). Finally, a crystalline thin SiC layer of 1.6 μm was elaborated using the PLD method at low-temperature indicating that the technique reproduces the same macroscopic property (optical, structural, mechanical, etc.) of the target.
EFFECTS OF THE NEXT-NEAREST-NEIGHBOR HOPPING IN OPTICAL LATTICES
Authors: GAO YUN'E , HAN FUXIANG
Published: January 2008

Introducing the next-nearest-neighbor hopping t′ into the Bose–Hubbard model, we study its effects on the phase diagram, on the ground-state energy, and on the quasiparticle and quasihole dispersion relations of the Mott insulating phase in optical lattices. We have found that a negative value of t′ enlarges the Mott-insulating region on the phase diagram, while a positive value of t′ acts oppositely. We have also found that the effects of t′ are dependent on the dimensionality of optical lattices with its effects largest in three-dimensional optical lattices.