bluuebunny/crossref_metadata_2025 huggingface dataset:
Corporate crime: opening the eyes of the sentry
Authors: Wells Celia
Published: May 2010

The relationship between criminal law and regulatory techniques in responses to corporate crime is complex and changing. The Serious Fraud Office's increased proactivity in relation to economic crime is precariously balanced on the fulcrum of criminal and regulatory rhetoric. In this paper I note significant developments and suggest that the similarities and differences between regulatory and criminal law approaches to corporate accountability are ripe for re-examination.
Mining online genomic resources inAnolis carolinensisfacilitates rapid and inexpensive development of cross‐species microsatellite markers for theAnolislizard genus
Authors: WORDLEY CLAIRE , SLATE JON , STAPLEY JESSICA
Published: May 2010

Online sequence databases can provide valuable resources for the development of cross‐species genetic markers. In particular, mining expressed tag sequences (EST) for microsatellites and developing conserved cross‐species microsatellite markers can provide a rapid and relatively inexpensive method to develop new markers for a range of species. Here, we adopt this approach to develop cross‐species microsatellite markers inAnolislizards, which is a model genus in evolutionary biology and ecology. Using EST sequences fromAnolis carolinensis,we identified 127 microsatellites that satisfied our criteria, and tested 49 of these in five species ofAnolis(carolinensis, distichus, apletophallus, porcatusandsagrei). We identified between 8 and 25 new variable genetic markers for fiveAnolisspecies. These markers will be a valuable resource for studies of population genetics, comparative mapping, mating systems, behavioural ecology and adaptive radiations in this diverse lineage.
Spatially explicit Bayesian clustering models in population genetics
Authors: FRANÇOIS OLIVIER , DURAND ERIC
Published: May 2010

This article reviews recent developments in Bayesian algorithms that explicitly include geographical information in the inference of population structure. Current models substantially differ in their prior distributions and background assumptions, falling into two broad categories: models with or without admixture. To aid users of this new generation of spatially explicit programs, we clarify the assumptions underlying the models, and we test these models in situations where their assumptions are not met. We show that models without admixture are not robust to the inclusion of admixed individuals in the sample, thus providing an incorrect assessment of population genetic structure in many cases. In contrast, admixture models are robust to an absence of admixture in the sample. We also give statistical and conceptual reasons why data should be explored using spatially explicit models that include admixture.
Limitations of mitochondrial gene barcoding in Octocorallia
Authors: McFADDEN CATHERINE S. , BENAYAHU YEHUDA , PANTE ERIC , THOMA JANA N. , NEVAREZ P. ANDREW , FRANCE SCOTT C.
Published: May 2010

The widespread assumption that COI and other mitochondrial genes will be ineffective DNA barcodes for anthozoan cnidarians has not been well tested for most anthozoans other than scleractinian corals. Here we examine the limitations of mitochondrial gene barcoding in the sub‐class Octocorallia, a large, diverse, and ecologically important group of anthozoans. Pairwise genetic distance values (uncorrected p) were compared for three candidate barcoding regions: the Folmer region of COI; a fragment of the octocoral‐specific mitochondrial protein‐coding gene, msh1; and an extended barcode of msh1 plus COI with a short, adjacent intergenic region (igr1). Intraspecific variation was <0.5%, with most species exhibiting no variation in any of the three gene regions. Interspecific divergence was also low: 18.5% of congeneric morphospecies shared identical COI barcodes, and there was no discernible barcoding gap between intra‐ and interspecific p values. In a case study to assess regional octocoral biodiversity, COI and msh1 barcodes each identified 70% of morphospecies. In a second case study, a nucleotide character‐based analysis correctly identified 70% of species in the temperate genus Alcyonium. Although interspecific genetic distances were 2× greater for msh1 than COI, each marker identified similar numbers of species in the two case studies, and the extended COI + igr1 + msh1 barcode more effectively discriminated sister taxa in Alcyonium. Although far from perfect for species identification, a COI + igr1 + msh1 barcode nonetheless represents a valuable addition to the depauperate set of characters available for octocoral taxonomy.
New primers for sex identification in the Chinese Egret and other ardeid species
Authors: WANG ZENG , ZHOU XIAOPING , LIN QINGXIAN , FANG WENZHEN , CHEN XIAOLIN
Published: May 2010

Using the universal P2/P8 primers, we were able to obtain the gene segments of chromo‐helicase‐DNA binding protein (CHD)‐Z and CHD‐W from ten species of ardeid birds including Chinese egret (Egretta eulophotes), little egret (E. garzetta), eastern reef egret (E. sacra), great egret (Ardea alba), grey heron (A. cinerea), Chinese pond‐heron (Ardeola bacchus), cattle egret (Bubulcus ibis), black‐crowned night‐heron (Nycticorax nycticorax), cinnamon bittern (Ixobrychus cinnamomeus) and yellow bittern (I. sinensis). Based on conserved regions inside the P2/P8‐derived sequences, we designed new PCR primers for sex identification in these ardeid species. Using agarose gel electrophoresis, the PCR products showed two bands for females (140 bp derived from CHD‐W and the other 250 bp from CHD‐ZW), whereas the males showed only the 250 bp band. The results indicated that our new primers could be used for accurate and convenient sex identification in ardeid species.
Can North Korea Develop? Developmental Dictatorship versus the China Reform Model
Authors: Izatt Hilary Jan
Published: May 2010

Assuming that economic development in North Korea is possible and a priority among the elite, this study compares Chinese and South Korean development strategies the DPRK could implement. While perfect application of another state's development strategy is impossible, historical, demographic, and ideological affinities with South Korea make for a better fit. However, such developmental prospects are largely reliant on international cooperation and acceptance. Applying the South Korean experience to North Korea's developmental prospects is fruitful and opens up a new debate about how the DPRK might achieve some economic parity to its East Asian neighbors.
Toward an Integrated Curriculum: Maximizing the Use of Target Language Literature
Authors: Barrette Catherine M. , Paesani Kate , Vinall Kimberly
Published: May 2010

Abstract: This article presents an approach to literary texts that develops students' language proficiency, content knowledge, and analytical skills through the interweaving of three content areas—literary analysis, stylistics, and culture—at the beginning, intermediate, and advanced levels of the foreign language curriculum. Consistent with recommendations from the recent Modern Language Association (2007) report on foreign languages in higher education, this integrated approach develops students' translingual and transcultural competence by examining target language narratives from multiple perspectives. To ground this method, we review relevant research on literature in foreign language instruction and then present a sample lesson plan for teaching the Spanish‐language text Apocalipsis [Apocalypse] (Denevi, 1974) at the intermediate instructional level. The article concludes with suggestions and strategies for modifying the lesson plan for beginning and advanced levels.
Acquisition of Spanish Gender Agreement in Two Learning Contexts: Study Abroad and At Home
Authors: Isabelli‐García Christina
Published: May 2010

Abstract: The goal of this study is to describe the acquisition rate for gender acquisition in Spanish and to show whether individual variability and language contact may affect this rate. The participants were intermediate second language Spanish (first language English) learners in the study abroad and at‐home contexts over a 4‐month period. The participants received grammaticality judgment tests coded for morphological class of the modified noun as well as attributive and predicative adjectives. Data were also collected on social behavior and language contact in Spanish and English in order to explain data outcome. The findings suggest that no difference exists between the two learning contexts and that social behavior and language contact abroad have minimal influence on acquisition rate.
Raising Voice – Securing a Livelihood: The Role of Diverse Voices in Developing Secure Livelihoods in Pastoralist Areas in Ethiopia
Authors: Brocklesby Mary Ann , Hobley Mary , Scott‐Villiers Patta
Published: May 2010

This paper is concerned with the workings of voice among pastoralists in Ethiopia. It documents how diverse pastoralist men and women – young and old, rich and poor – call on one another and on representatives and officials in efforts to achieve cooperation and influence. Diverse pastoralists explain how successful voice is the result of interconnectedness and opportunity. Individual influence varies with a speaker's social and political connections, with his or her determination, skill and experience, and as a consequence of geography and politics.

In this study we learned that to be successful as a pastoralist in Ethiopia is to be ‘competent’ and to be competent is to have voice. People want to build capabilities to develop and manage assets, make demands, and secure and give support. Competence can be appreciated in their mobility, visibility, audibility and action: moving to watering and grazing places at the right time, bringing up children and managing the household well, being seen doing business in town, speaking effectively at clan and government meetings, being generous in welfare and wise in justice. Competence and voice are the basis of wealth and a bulwark against hard times, going beyond ideas of social, economic or political capital to embrace Amartya Sen's notion of capability and agency, constantly renewed in interconnection and discussion (Sen 1999).

In speaking, people are seeking binding responses, although often all they get are false assurances or rebuff. Poor pastoralists, clustering in increasing numbers around the edges of settlements, say that they are becoming powerless objects of state welfare, disconnected and unable to regain competence, still less contribute to society's wellbeing. The response of pastoralist leaders has been to increase the level of engagement between different pastoralists, while increasing the intensity of their public engagements with the state.
Sensitivity of stable isotope mixing models to variation in isotopic ratios: evaluating consequences of lipid extraction
Authors: Tarroux Arnaud , Ehrich Dorothée , Lecomte Nicolas , Jardine Timothy D. , Bêty Joël , Berteaux Dominique
Published: May 2010

1. Stable isotopes of carbon and nitrogen are increasingly used in studies of animal diet reconstruction via mixing models. However, isotope ratios of both consumer and source tissues can be altered by various amounts of lipids, potentially leading to biased estimates of diet composition when they are not taken into account.

2. We investigated the consequences of lipid correction on the estimation of diet composition with mixing models. Using empirical data from three northern terrestrial trophic systems, we illustrated the direct effects of lipid extraction (LE) on the δ13C and δ15N of source and consumer tissues and its ultimate effects on the reconstruction of the consumer’s diet.

3. In parallel, we developed a simulation tool in R, called fatsim, to assess sensitivity of mixing models to variation in isotopic ratios of samples from source or consumer tissues. This tool can be used to assess the effect of shifts in isotopic ratios caused by LE, or other sources of variation, in any trophic system and thus aid in decision making regarding lipid removal.

4. Using fatsim, we showed that the potential effects of LE on estimates of diet composition cannot be predicted without simulations, even in relatively simple systems. The sensitivity of a mixing model isotopic shift depends on the complexity of the system (number of sources) and on the relative positions of sources and consumers within the isotopic mixing space.

5. Our study confirms that the presence of lipids in tissues can bias the interpretation of diet reconstruction results. In a given trophic system, testing the sensitivity of a mixing model to LE can help decide whether lipid removal is required in order to avoid this bias.
Free Response and Absolute Vibration Suppression of Second-Order Flexible Structures—The Traveling Wave Approach
Authors: Sirota Lea , Halevi Yoram
Published: May 2010

The paper considers the problem of suppressing the free vibration, induced by nonzero initial conditions, in a flexible system governed by the wave equation. First an exact response of the system, with general linear boundary conditions, is derived in terms of propagating waves that are reflected from the boundaries. The solution is explicit and with clear physical interpretation. The general expressions for the response are then used to investigate the behavior of the system under control with the absolute vibration suppression controller, which was originally designed for tracking control. It is shown that the vibration suppression properties of this controller apply also to nonzero initial conditions. In cases where the load end is free or contains only damping, the vibration stops completely in finite time and if it contains only inertia and damping it decays exponentially without vibration.
Influence of Multiphysical Effects on the Dynamics of the High Speed Mini Rotors—Part II: Results
Authors: Dikmen Emre , van der Hoogt Peter J. M. , de Boer André , Aarts Ronald G. K. M.
Published: May 2010

In Part I of this work, a theoretical analysis showed that the surrounding air in the closed confinement between rotor and casing has a significant effect on the dynamic behavior of high speed minirotors. In order to validate the developed theoretical model, an experimental setup is designed and the dynamic behavior of the rotor with medium gap confinement is studied. The experimental setup has flexible supports, which consist of beams with adjustable length. The support stiffness is changed by altering the beam length. Modal analysis of the rotor is done in free-free conditions in order to test the capability of the rotordynamic model without the supports and multiphysical effects. The experimental and simulation results agree well with a difference of 1%. Then modal analysis of the whole structure is done at standstill and during operation in the absence of the casing. In this way, multiphysical effects are eliminated and only support effects on the dynamics of the structure are observed. The supports appear to have significant effect on the natural frequencies of the flexural modes of the system. Different support modeling techniques are studied and adequate equivalent models are obtained. These models are then implemented into the structural model of the rotor. Finally, multiphysical effects are tested at different speeds with different support stiffnesses. Experiments are performed with and without the casing for determining the change in the natural frequencies and onset of instability. The surrounding fluid has a significant effect on the stability of the system while the natural frequencies do not change significantly. The experimental and theoretical results are in fair agreement for predicting the natural frequencies and the onset of instability.
An Experimental Investigation of Coupled van der Pol Oscillators
Authors: Choubey Bhaskar
Published: May 2010

Experimental investigations of synchronization of linearly diffusive coupled van der Pol electronic oscillators are reported. In addition to in- and antiphase stable oscillations, shifted symmetric and asymmetric trajectories have been observed experimentally. However, the experiments have failed to produce stable chaotic behavior in these systems. Extended numeric simulations are then performed to show that the previously believed chaotic region is a transient numeric effect, thereby validating experimental results.
Two-Dimensional Modeling of Nanomechanical Strains in Healthy and Diseased Single-Cells During Microfluidic Stress Applications
Authors: Wilson Zachary D. , Kohles Sean S.
Published: May 2010

Investigations in cellular and molecular engineering have explored the impact of nanotechnology and the potential for monitoring and control of human diseases. In a recent analysis, the dynamic fluid-induced stresses were characterized during microfluidic applications of an instrument with nanometer and picoNewton resolution as developed for single-cell biomechanics (Kohles, S. S., Nève, N., Zimmerman, J. D., and Tretheway, D. C., 2009, “Stress Analysis of Microfluidic Environments Designed for Isolated Biological Cell Investigations,” ASME J. Biomech. Eng., 131(12), p. 121006). The results described the limited stress levels available in laminar, creeping-flow environments, as well as the qualitative cellular strain response to such stress applications. In this study, we present a two-dimensional computational model exploring the physical application of normal and shear stress profiles (with 0.1, 1.0, and 10.0 Pa peak amplitudes) potentially available within uniform and extensional flow states. The corresponding cellular strains and strain patterns were determined within cells modeled with healthy and diseased mechanical properties (5.0–0.1 kPa moduli, respectively). Strain energy density results integrated over the volume of the planar section indicated a strong mechanical sensitivity involving cells with disease-like properties. In addition, ex vivo microfluidic environments creating in vivo stress states would require freestream flow velocities of 2–7 mm/s. Knowledge of the nanomechanical stresses-strains necessary to illicit a biologic response in the cytoskeleton and cellular membrane will ultimately lead to refined mechanotransduction relationships.
Continuous Variable Transmission With an Inertia-Regulating System
Authors: Centeno G. , Morales F. , Perez F. B. , Benitez F. G.
Published: May 2010

This article describes a power transmission system applicable to vehicles. It consists of an oscillating, ratcheting-type, continuously variable transmission (CVT) system governed by an inertia mechanism. The inertia-regulating mechanism adds an additional degree of freedom and gives the system a dynamic character. The transmission consists of three different subsystems. The first of these converts the rotation of the engine or motor into an oscillating angular velocity movement and regulates the amplitude of this movement. The oscillating rotation from the first subsystem is used to drive a second subsystem, which acts as a regulating device by means of an inertial mechanism. The oscillating movement at the output of the second subsystem is rectified in the third, resulting in a unidirectional angular velocity. As a result, a unidirectional torque is generated at the output of the CVT, commensurate with the operating condition of the transmission, and this is capable of overcoming a torque resistance. A prototype of this transmission was built and tested to check the experimental results against those predicted by a series of computational simulations. As a result, the experimental graphs that characterize the operation of this type of transmission system were obtained, demonstrating its ability to function in an efficient manner.
Integrated Design and Optimization of Gas Bearing Supported Rotors
Authors: Schiffmann J. , Favrat D.
Published: May 2010

The design of direct driven turbomachinery is an interdisciplinary task. Standard design procedures propose to split such systems into subcomponents and to design each one individually. This common procedure, however, tends to neglect the interactions between the different components leading to suboptimal solutions. The authors propose an approach based on the integrated philosophy for designing and optimizing gas bearing supported rotors. Based on the choice for herringbone grooved journal and spiral groove thrust bearings, the modeling procedure for predicting their properties and the linking to the rotordynamic behavior of a generic rotor supported on gas lubricated bearings is provided. The global model for gas bearing supported rotors is linked to a multiobjective optimizer for maximizing the dynamic stability and for minimizing the windage losses of the rotor and of the bearings. Two typical rotor layouts have been included in the optimization. The geometry of a proof of concept system, that has been designed previously using the fragmented component view, is represented as a comparison to the proposed integrated approach. It is shown that the integrated solution allows to reduce the windage losses by 25% or to increase the stability margin by 35%, emphasizing the advantage of the proposed integrated design tool.
A Method for the Preliminary Geometric Design of Gear Tooth Profiles With Small Sliding Coefficients
Authors: Wang Jian , Luo Shanming , Wu Yue
Published: May 2010

This paper proposes a method of the preliminary geometric design for gear tooth profiles based on given sliding coefficients. A design procedure is developed and a simplified derivation of the mathematical model of tooth profiles is presented. The characteristics of the gear drive designed by the proposed method are analyzed. A comparison study on the sliding coefficient with the involute gear drive is also carried out in this work. The effects of parameters, including tooth number and modulus, on the characteristics of the gear drives are studied. The contact and bending stresses of this new drive are also analyzed. A manufacturing method of the proposed gear is studied, and a simulation of the machining process demonstrates its feasibility. The results show that the designers can design tooth profiles according to required sliding coefficients by the proposed method.
Development of Carbon Nanotube Based Through-Silicon Vias
Authors: Kim Bruce C. , Kannan Sukeshwar , Gupta Anurag , Mohammed Falah , Ahn Byoungchul
Published: May 2010

The design and development of reliable 3D integrated systems require high performance interconnects, which in turn are largely dependent on the choice of filler materials used in through-silicon vias (TSVs). Copper, tungsten, and poly-silicon have been explored as filler materials; however, issues such as thermal incompatibility, electromigration, and high resistivity are still a bottleneck. In this paper, we investigate single-walled carbon nanotube (CNT) bundles as a prospective filler material for TSVs and have provided an analysis of CNT based TSVs for package and chip interconnects. The interconnects are fundamental bottlenecks to achieving high performance and reliability. We have provided electrical modeling and performed simulations on TSVs with copper and carbon nanotubes. The results from the CNT based TSVs were greatly superior to those from the conventional vias with copper.
On the Path-Dependence of the J-Integral Near a Stationary Crack in an Elastic-Plastic Material
Authors: Carka Dorinamaria , Landis Chad M.
Published: May 2010

The path-dependence of the J-integral is investigated numerically via the finite-element method, for a range of loadings, Poisson’s ratios, and hardening exponents within the context of J2-flow plasticity. Small-scale yielding assumptions are employed using Dirichlet-to-Neumann map boundary conditions on a circular boundary that encloses the plastic zone. This construct allows for a dense finite-element mesh within the plastic zone and accurate far-field boundary conditions. Details of the crack tip field that have been computed previously by others, including the existence of an elastic sector in mode I loading, are confirmed. The somewhat unexpected result is that J for a contour approaching zero radius around the crack tip is approximately 18% lower than the far-field value for mode I loading for Poisson’s ratios characteristic of metals. In contrast, practically no path-dependence is found for mode II. The applications of T- or S-stress, whether applied proportionally with the K-field or prior to K, have only a modest effect on the path-dependence.
Drawing an elephant with four complex parameters
Authors: Mayer Jürgen , Khairy Khaled , Howard Jonathon
Published: May 2010

We define four complex numbers representing the parameters needed to specify an elephantine shape. The real and imaginary parts of these complex numbers are the coefficients of a Fourier coordinate expansion, a powerful tool for reducing the data required to define shapes.
High-altitude free fall revised
Authors: Benacka Jan
Published: May 2010

This paper considers a model of free fall in the troposphere (altitude of up to 11 km) that takes into account the decrease of the air density, temperature, and the speed of sound. Two cases are analyzed: The maximum speed is less than Mach 0.8 (subsonic fall) for which the drag coefficient is constant, and the maximum speed exceeds Mach 0.8 (transonic and supersonic fall) for which the drag coefficient depends on the speed. The equation of motion is solved analytically for subsonic fall, and the range of validity of the solution is found. The solution for supersonic fall in the troposphere is found for the free fall of a bomb. The drag coefficient function is obtained by a least square fit to measured data, and the differential equation is solved numerically.
A constructive approach to the special theory of relativity
Authors: Miller D. J.
Published: May 2010

Simple physical models of a measuring rod and of a clock are used to demonstrate the contraction of objects and clock retardation in special relativity. It is argued that models can help student understanding of special relativity and distinguishing between dynamical and purely perspectival effects.
Acoustic cloaking using layered pentamode materials
Authors: Scandrett Clyde L. , Boisvert Jeffrey E. , Howarth Thomas R.
Published: May 2010

While receiving less attention in the literature than electromagnetic cloaking, theoretical efforts to define and create acoustic cloaks based upon mimicking coordinate transformations through use of metamaterials is of interest. The present work extends recent analysis of Norris [Proc. R. Soc. London, Ser. A 464, 2411–2434 (2008)] by considering a range of cloaks, from those comprised of fluid layers which are isotropic in bulk moduli with anisotropic density to those having anisotropic bulk moduli and isotropic density. In all but pure inertial varieties, fluid layers comprising the cloaks are pentamode materials governed by a special scalar acoustic equation for pseudopressure derived by Norris. In most cases presented, material properties of the fluid/pentamode layers are based upon target values specified by continuously varying properties resulting from theoretical coordinate transformations geared to minimize scattered pressure limited by realistic goals. The present work analyzes such cloaks for the specific case of plane wave scattering from an acoustically hard sphere. An initial exploration of the parameter space defining such cloaks (for example, material properties of its constituent layers, and operating frequency) is undertaken with a view toward “optimal” design.
A covariance fitting approach for correlated acoustic source mapping
Authors: Yardibi Tarik , Li Jian , Stoica Petre , Zawodny Nikolas S. , Cattafesta Louis N.
Published: May 2010

Microphone arrays are commonly used for noise source localization and power estimation in aeroacoustic measurements. The delay-and-sum (DAS) beamformer, which is the most widely used beamforming algorithm in practice, suffers from low resolution and high sidelobe level problems. Therefore, deconvolution approaches, such as the deconvolution approach for the mapping of acoustic sources (DAMAS), are often used for extracting the actual source powers from the contaminated DAS results. However, most deconvolution approaches assume that the sources are uncorrelated. Although deconvolution algorithms that can deal with correlated sources, such as DAMAS for correlated sources, do exist, these algorithms are computationally impractical even for small scanning grid sizes. This paper presents a covariance fitting approach for the mapping of acoustic correlated sources (MACS), which can work with uncorrelated, partially correlated or even coherent sources with a reasonably low computational complexity. MACS minimizes a quadratic cost function in a cyclic manner by making use of convex optimization and sparsity, and is guaranteed to converge at least locally. Simulations and experimental data acquired at the University of Florida Aeroacoustic Flow Facility with a 63-element logarithmic spiral microphone array in the absence of flow are used to demonstrate the performance of MACS.
Rhenium diboride’s monocrystal elastic constants, 308 to 5 K
Authors: Suzuki Yoko , Levine Jonathan B. , Migliori Albert , Garrett Jim D. , Kaner Richard B. , Fanelli Victor R. , Betts Jonathan B.
Published: May 2010

The five independent moduli required to construct the complete monocrystal elastic modulus tensor of the hexagonal-symmetry superhard compound ReB2 were measured from 308 to 5 K using resonant ultrasound spectroscopy on a special-texture polycrystal. This is possible because, confirmed by X-ray diffraction, the specimen measured was composed of grains with hexagonal axes parallel so that its polycrystal elastic response is identical to a monocrystal and because hexagonal-symmetry solids are elastically isotropic in the plane perpendicular to the hexagonal axis. Along the hexagonal (c) axis, C330=1021 GPa, nearly equal to C11 of diamond, and consistent with the superhard properties. However, in the (softer) isotropic plane, C110=671 GPa, much lower than diamond. The changes of Cij with temperature are very small and smooth. The Debye temperature was computed to be 738 K, and using a high-temperature approximation, the Grüneisen parameter is γ=1.7.
Effect of stimulus level and place of stimulation on temporal pitch perception by cochlear implant users
Authors: Carlyon Robert P. , Lynch Catherine , Deeks John M.
Published: May 2010

Three experiments studied the effect of pulse rate on temporal pitch perception by cochlear implant users. Experiment 1 measured rate discrimination for pulse trains presented in bipolar mode to either an apical, middle, or basal electrode and for standard rates of 100 and 200 pps. In each block of trials the signals could have a level of −0.35, 0, or +0.35 dB re the standard, and performance for each signal level was recorded separately. Signal level affected performance for just over half of the combinations of subject, electrode, and standard rate studied. Performance was usually, but not always, better at the higher signal level. Experiment 2 showed that, for a given subject and condition, the direction of the effect was similar in monopolar and bipolar mode. Experiment 3 employed a pitch comparison procedure without feedback, and showed that the signal levels in experiment 1 that produced the best performance for a given subject and condition also led to the signal having a higher pitch. It is concluded that small level differences can have a robust and substantial effect on pitch judgments and argue that these effects are not entirely due to response biases or to co-variation of place-of-excitation with level.
Multiple-array passive acoustic source localization in urban environments
Authors: Mennitt Daniel , Johnson Marty
Published: May 2010

In many situations of interest, obstacles to acoustic wave propagation such as terrain or buildings exist that provide unique challenges to localization. These obstacles introduce multiple propagation paths, reflections, and diffraction into the propagation. In this paper, matched field processing is proposed as an effective method of acoustic localization in a two dimensional scattering environment. Numerical techniques can be used to model complex propagation in a space where analytical solutions are not feasible. Realistically, there is always some uncertainty in model parameters that in turn can adversely affect localization ability. In particular, uncertainty in array location, sound speed, and various parameters affecting inter-array coherence only are investigated. A spatially distributed, multiarray network is shown to mitigate the effects of uncertainty. Multiarray inverse filter processing techniques are evaluated through perturbation of uncertain model parameters. These techniques are more accurate and flexible to implement than other matched field processing methods such as time reversal.
Compliance profiles derived from a three-dimensional finite-element model of the basilar membrane
Authors: Fleischer Mario , Schmidt Rolf , Gummer Anthony W.
Published: May 2010

A finite-element analysis is used to explore the impact of elastic material properties, boundary conditions, and geometry, including coiling, on the spatial characteristics of the compliance of the unloaded basilar membrane (BM). It is assumed that the arcuate zone is isotropic and the pectinate zone orthotropic, and that the radial component of the effective Young’s modulus in the pectinate zone decreases exponentially with distance from base to apex. The results concur with tonotopic characteristics of compliance and neural data. Moreover, whereas the maximum compliance in a radial profile is located close to the boundary between the two zones in the basal region, it shifts to the midpoint of the pectinate zone for the apical BM; the width of the profile also expands. This shift begins near the 1 kHz characteristic place for guinea pig and the 2.4 kHz place for gerbil. Shift and expansion are not observed for linear rather than exponential decrease of the radial component of Young’s modulus. This spatial change of the compliance profile leads to the prediction that mechanical excitation in the apical region of the organ of Corti is different to that in the basal region.
Ray splitting in the reflection and refraction of surface acoustic waves in anisotropic solids
Authors: Every A. G. , Maznev A. A.
Published: May 2010

This paper examines the conditions for, and provides examples of, ray splitting in the reflection and refraction of surface acoustic waves (SAW) in elastically anisotropic solids at straight obstacles such as edges, surface breaking cracks, and interfaces between different solids. The concern here is not with the partial scattering of an incident SAW’s energy into bulk waves, but with the occurrence of more than one SAW ray in the reflected and/or transmitted wave fields, by analogy with birefringence in optics and mode conversion of bulk elastic waves at interfaces. SAW ray splitting is dependent on the SAW slowness curve possessing concave regions, which within the constraint of wave vector conservation parallel to the obstacle allows multiple outgoing SAW modes for certain directions of incidence and orientation of obstacle. The existence of pseudo-SAW for a given surface provides a further channel for ray splitting. This paper discusses some typical material configurations for which SAW ray splitting occurs. An example is provided of mode conversion entailing backward reflection or negative refraction. Experimental demonstration of ray splitting in the reflection of a laser generated SAW in GaAs(111) is provided. The calculation of SAW mode conversion amplitudes lies outside the scope of this paper.
Acoustic temperature measurement in a rocket noise field
Authors: Giraud Jarom H. , Gee Kent L. , Ellsworth John E.
Published: May 2010

A 1 μm diameter platinum wire resistance thermometer has been used to measure temperature fluctuations generated during a static GEM-60 rocket motor test. Exact and small-signal relationships between acoustic pressure and acoustic temperature are derived in order to compare the temperature probe output with that of a 3.18 mm diameter condenser microphone. After preliminary plane wave tests yielded good agreement between the transducers within the temperature probe’s ∼2 kHz bandwidth, comparison between the temperature probe and microphone data during the motor firing show that the ±∼3 K acoustic temperature fluctuations are a significant contributor to the total temperature variations.
Vibrational characteristics of Balinese gamelan metallophones
Authors: Jones Molly E. , Gee Kent L. , Grimshaw Jeremy
Published: May 2010

A study of the eight metallophone pairs from a Balinese gamelan semara dana has been conducted. Acoustical recordings of metallophone bars being struck were used to examine ratios of overtone frequencies to the fundamental. Results showed large variability in the number and ratios of overtones present. Scanning laser Doppler vibrometry measurements made on several bars also revealed great variability in mode shapes present. The distribution of prominent overtones and their modal shapes do not appear to match those of Western metallophones. Notably, the overall gamelan metallophone characteristics are quite dissimilar to the glockenspiel, which disagrees with previous studies.
Comments on single-mass models of vocal fold vibration
Authors: McGowan Richard S. , Howe Michael S.
Published: May 2010

Proposed mechanisms for single-mass oscillation in the vocal tract are examined critically. There are two areas that distinguish single-mass models: in the sophistication of the air flow modeling near the oscillator and whether or not oscillation depends on acoustic feedback. Two recent models that do not depend on acoustic feedback are examined in detail. One model that depends on changing flow separation points is extended with approximate calculations.
Tuberculosis: What We Don’t Know Can, and Does, Hurt Us
Authors: Russell David G. , Barry Clifton E. , Flynn JoAnne L.
Published: May 2010

Mycobacterium tuberculosis
has a penetrance of its host population that would be the envy of most human pathogens. About one-third of the human population would have a positive skin test for the infection and is thus thought to harbor the bacterium. Globally, 22 “high-burden” countries account for more than 80% of the active tuberculosis cases in the world, which shows the inequitable distribution of the disease. There is no effective vaccine against infection, and current drug therapies are fraught with problems, predominantly because of the protracted nature of the treatment and the increasing occurrence of drug resistance. Here we focus on the biology of the host-pathogen interaction and discuss new and evolving strategies for intervention.
Resource Management Cycles and the Sustainability of Harvested Wildlife Populations
Authors: Fryxell John M. , Packer Craig , McCann Kevin , Solberg Erling J. , Sæther Bernt-Erik
Published: May 2010

Population Meltdown

Populations of wild animals, including deer and moose, are often actively managed by hunting. Following such harvesting, populations of some exploited animal species collapse, whereas others are able to withstand exploitation. To understand the reasons for these varied responses,

Fryxell
et al.

(p.
903
) developed a mathematical model which predicts that weak regulation causes damped population cycles with period lengths on the order of decades. The model was tested using time-series data for hunted populations of moose and deer in three ecosystems in Norway and Canada.
Heterogeneous Accretion and the Moderately Volatile Element Budget of Earth
Authors: Schönbächler M. , Carlson R. W. , Horan M. F. , Mock T. D. , Hauri E. H.
Published: May 2010

Earth's Silver Lining

The age of the oldest rocks on Earth's surface is controversial, but, even if they are at their oldest estimate, hundreds of millions of years in our planet's earliest history are still missing. However, in some rocks that until relatively recently resided in the mantle, the isotopic signature from the time of Earth's formation is still preserved.

Schönbächler
et al.

(p.
884
) exploited this preservation to constrain models that describe the early material that assembled together to form Earth. Because the isotopic profile of silver in these rocks is nearly identical to that measured in a class of primitive meteorites, the earliest material probably had high volatile content. However, the fractionation of other isotopes suggests that the volatile content probably decreased over time in subsequent accretion events. With these isotopic model constraints, it is possible that one of the last major collisions—the Moon-forming giant impact—added considerable amounts of water and other volatile elements to Earth.
A Plant-Like Kinase in
Plasmodium falciparum
Regulates Parasite Egress from Erythrocytes
Authors: Dvorin Jeffrey D. , Martyn Derek C. , Patel Saurabh D. , Grimley Joshua S. , Collins Christine R. , Hopp Christine S. , Bright A. Taylor , Westenberger Scott , Winzeler Elizabeth , Blackman Michael J. , Baker David A. , Wandless Thomas J. , Duraisingh Manoj T.
Published: May 2010

It's a Knockout

The malaria parasite is one of the most important pathogens of humans. Increasing drug-resistance is an imminent public health disaster, and we urgently need to find new drugs. The recently acquired malarial genomes provide a plethora of targets. However, due to the genetic intractability of the parasite, it has been difficult to identify essential genes in the clinically relevant blood-stage of the parasite.

Dvorin
et al.

(p.
910
) investigated the function of a
Plasmodium falciparum
plant-like calcium-dependent protein kinase, PfCDPK5, which is expressed in the invasive blood-stage forms of the parasite. A system for conditional protein expression allowed the production of a functional knockout in the bloodstream stage of the parasite. PfCDPK5 was required for parasite egress from the human host erythrocyte, an essential step in the parasite life cycle.
Narrow Primary Feather Rachises in
Confuciusornis
and
Archaeopteryx
Suggest Poor Flight Ability
Authors: Nudds Robert L. , Dyke Gareth J.
Published: May 2010

Poor Flight of the Ancients

In order to fly, the feathers of birds must be strong enough to support the bird's weight without breaking or bending. The main part of a feather providing structural support is its central shaft, which stiffens the feather along its length. In modern birds, this is hollow to reduce weight.
Nudds and Dyke
(p.
887
) show that the cross-section of the shaft of the Mesozoic birds
Archaeopteryx
and
Confuciusornis
was much smaller than that of modern birds. Calculations imply that even if it was solid, it would have been too weak to support powered flight and barely strong enough to allow gliding. Thus, powered flight probably arose later in the evolution of birds and these early birds were poor fliers.
Dam Controversy
The Dawn of Green
Manchester, Thirlmere, and Modern Environmentalism

by Harriet Ritvo

University of Chicago Press, Chicago, 2009. 245 pp., $26, £18. ISBN 9780226720821.
Authors: Luckin Bill
Published: May 2010

Ritvo describes the 19th-century clash over the fate of a Lake District valley in England and its importance to continuing debates on conservation.
Assembling the Outer Membrane
Authors: Stroud David A. , Meisinger Chris , Pfanner Nikolaus , Wiedemann Nils
Published: May 2010

Multisubunit machineries insert β-barrel proteins into the outer membranes of bacteria and mitochondria.
Elimination Meets Reality in Hispaniola
Authors: Roberts Leslie
Published: May 2010

Hispaniola's fledging program to eliminate malaria, now sidetracked by the earthquake, illustrates the difficulties that arise when ambitious goals collide with reality.
Comparison of Single-Copy and Multicopy Real-Time PCR Targets for Detection of
Mycobacterium tuberculosis
in Paraffin-Embedded Tissue
Authors: Luo Robert F. , Scahill Michael D. , Banaei Niaz
Published: May 2010

Real-time PCR can rapidly identify
Mycobacterium tuberculosis
in paraffin-embedded tissue in the absence of microbiological culture. In a comparison of single-copy and multicopy PCR targets in 70 tissue samples, the sensitivities were 26% and 54%, respectively, with 100% specificity. Sensitivity was 75% for newer samples and was not decreased for acid-fast bacillus (AFB) stain-negative specimens.
Trends in Fishing Mortality Rate along with Errors in Natural Mortality Rate can cause Spurious Time Trends in Fish Stock Abundances Estimated by Virtual Population Analysis (VPA)
Authors: Lapointe Michael F. , Peterman Randall M. , MacCall Alec D.
Published: May 2010

Many researchers have reported biases in estimates offish abundance reconstructed by virtual population analysis (VPA). We document that VPA can produce changing levels of bias through time, thereby creating spurious time trends in recruitment and stock biomass estimates. We generated catch data from empirically based simulations of nine fish populations, estimated abundances using VPA with a deliberately mis-specified natural mortality rate, M, and compared the estimates to the models' "true" abundances. A period of increasing fishing mortality rate, F, combined with an overestimate of M produced spurious decreasing time trends in estimated abundance and recruitment, even when the true time series of F was known. Analogously, an underestimate of M led to a spurious increasing time trend. Bias was increased by a higher true M, and (for a given total change in F) by a slower increase in F. Because field estimates of M are uncertain and trends in F are common, some apparent trends (or lack of them) in abundances reconstructed by VPA may be artifacts. Therefore, inferences about the results of past management actions and about physical or biological effects on variability in recruitment must be made cautiously when VPA estimates are used.
Perturbation Planktivory, and Pelagic Community Structure: The Consequence of Winterkill in a Small Lake
Authors: Hail Donald J. , Ehlinger Timothy J.
Published: May 2010

The top predator (largemouth bass, Micropterus salmoides) in eutrophic Wintergreen Lake, Michigan, was eliminated by successive winterkills in 1978 and 1979. Within 2 yr, the golden shiner (Notemigonus crysoleucas), a facultative planktivore, dominated the fish community. The zooplankton, previously consisting of large Daphnia pulex and D. galeata mendotae, concomitantly shifted to a community consisting of smaller species: Bosmina and small copepods. In situ fish enclosure experiments in 1981 and 1982 revealed that the large Daphnia species would grow in Wintergreen Lake in the absence of the golden shiner. Golden shiners exhibit both a particulate and filtering mode of planktivory on large and small zooplankton, respectively. This flexible feeding behavior suggests that golden shiners are able to prevent the reestablishment of Daphnia, while Bosmina and the other small zooplankton support a high and apparently stable golden shiner density.
GENERALIZED RICCI FLOW AND SUPERGRAVITY VACUUM SOLUTIONS
Authors: HU SEN , HU ZHI , ZHANG RUORAN
Published: May 2010

We first give a proof that the supersymmetric configurations satisfy the equations of motion for type II supergravity. In flux compactifications, the string vacua preserving N = 2 supersymmetry are the twisted generalized Calabi–Yau manifold. The modulus space of the string vacua can be constructed. We discuss the generalized Dirac operator which adds a torsional term to the ordinary Dirac operator and compute its index by the path integral method. Via the variation of the action of supergravity one can introduce the generalized Ricci flow equations. We consider deforming the manifold with the generalized Ricci flow. Finally, we consider the linear stability of the fixed points of the generalized Ricci flow.