bluuebunny/crossref_metadata_2025 huggingface dataset:
Fission‐fusion dynamics of Guiana dolphin (Sotalia guianensis) groups at Pipa Bay, Rio Grande do Norte, Brazil
Authors: Lunardi Diana G. , Ferreira Renata G.
Published: March 2014

Fission‐fusion dynamics seem to reflect individual decisions as well as temporal and spatial variations in the organization of groups of the same species. To understand the group dynamics of the Guiana dolphin, Sotalia guianensis, at Pipa Bay, Brazil, we investigated the three dimensions of a fission‐fusion social system: (1) variation in spatial cohesion, (2) variation in party size, and (3) variation in party composition. Sampling took place from December 2007 to February 2009 over 176 d and we analyzed the behavioral patterns of 658 groups. Within subgroups, animals remained cohesive, particularly in groups of adults and calves. Greater cohesion was also observed during resting and fission‐fusion rates were higher during milling and feeding. Groups composed of adults and juveniles showed a higher dynamics index (group size variation as a function of time) than groups composed only of adults and the fission‐fusion rate was higher during dry periods. Guiana dolphin groups frequently changed their group size and composition every 20 min on average. Taking these factors into consideration, we suggest that the Guiana dolphin demonstrates fission‐fusion dynamics, a pattern of behavior similar to what has been observed in other coastal odontocete species, such as Tursiops spp. and Lagenorhynchus obscurus.
Improvement of enteral nutrition in intensive care unit patients by a nurse‐driven feeding protocol
Authors: Friesecke Sigrun , Schwabe Anna , Stecher Stephanie‐Susanne , Abel Peter
Published: March 2014

Aims and objectives

To examine whether early enteral nutrition (EN) of critically ill patients could be improved by a nurse‐driven implementation of an existing feeding protocol.

Design

Before and after design.

Methods

Responsibility for starting and timely escalating EN – subject to physician's ordering before – was assigned to the intensive care unit (ICU) nursing staff. A short written instruction was extracted from the comprehensive standard operating procedure (SOP) for nutrition. The nursing team was trained to use this instruction; after completing the training they managed early EN autonomously.

Time to start of enteral feeding and applied quantity in the first 5 ICU days were recorded prospectively for the patients treated during the following 6 months. The data were compared to a retrospectively analysed cohort from 6 months before, which was fed according to the SOP‐based prescription of the physician on duty.

Results

A total of 101 and 97 patients were included, respectively, before and after the intervention. Following intervention, enteral feeding started significantly earlier (28 ± 20 h versus 47 ± 34 h, p < 0·001), within 24 h in 64% versus 25% (p < 0·0001); and for each of the first 5 days, the proportion of patients meeting their nutritional goal was significantly higher.

Conclusions

Assigning the responsibility for implementation of an existing SOP to the nursing team led to earlier start of enteral feeding and more frequent achievement of caloric targets in ICU patients.

Relevance to clinical practice

Adherence to guidelines regarding early start and timely escalation of EN can be improved if ICU nursing staff is responsible for translating it into action with the help of a written algorithm.
Current status of human hepatocyte transplantation and its potential for Wilson's disease
Authors: Filippi Celine , Dhawan Anil
Published: March 2014

Wilson's disease (WD) is a genetic disorder of liver copper excretion leading to its accumulation in various vital organs like the liver, brain, and kidneys. Drugs such as penicillamine, trientine, and zinc salts are the mainstay of treatment, with good outcomes; but nonresponders or a lack of compliance to the drug treatment can result in disease progression and acute liver failure (ALF). Current treatment for WD with ALF is an emergency liver transplantation and lifelong immunosuppression. Human hepatocyte transplantation (HTx) is increasingly used as treatment for liver‐based metabolic defects. HTx may benefit WD patients with ALF, either as transient support until chelation treatment shows its effect or as a definitive cure through liver repopulation by healthy donor cells, as shown in animal models of WD. Although clinical trials of HTx have already proven safety and efficacy in different ALF etiologies, it remains to be demonstrated similarly in cases of WD.
Overexpression of S‐adenosyl‐l‐methionine synthetase increased tomato tolerance to alkali stress through polyamine metabolism
Authors: Gong Biao , Li Xiu , VandenLangenberg Kyle M. , Wen Dan , Sun Shasha , Wei Min , Li Yan , Yang Fengjuan , Shi Qinghua , Wang Xiufeng
Published: March 2014

S‐adenosyl‐l‐methionine (SAM) synthetase is the key enzyme involved in the biosynthesis of SAM, which serves as a common precursor for polyamines (PAs) and ethylene. A SAM synthetase cDNA (SlSAMS1) was introduced into the tomato genome using the Agrobacterium tumefaciens transformation method. Transgenic plants overexpressing SlSAMS1 exhibited a significant increase in tolerance to alkali stress and maintained nutrient balance, higher photosynthetic capacity and lower oxidative stress compared with WT lines. Both in vivo and in vitro experiments indicated that the function of SlSAMS1 mainly depended on the accumulation of Spd and Spm in the transgenic lines. A grafting experiment showed that rootstocks from SlSAMS1‐overexpressing plants provided a stronger root system, increased PAs accumulation, essential elements absorption, and decreased Na+ absorption in the scions under alkali stress. As a result, fruit set and yield were significantly enhanced. To our knowledge, this is the first report to provide evidence that SlSAMS1 positively regulates tomato tolerance to alkali stress and plays a major role in modulating polyamine metabolism, resulting in maintainability of nutrient and ROS balance.
Encyclopaedic Erasmus
Authors: Cummings Brian
Published: March 2014

Copiousness as an idea is centrally identified with Erasmus. De copia was a milestone in establishing Erasmus as a humanist scholar after its first publication in Paris in 1512. In turn, this book was a major influence on theories of rhetoric, and of writing in general, throughout the sixteenth century. Following on from Cicero, Erasmus argues that style must be abundant in order to be effective, and that abundance consists of two primary elements: variety of expression and variety of subject matter. Copiousness is the key to writing, or to language, or even to an idea of knowledge. This article analyses the theory of copiousness in Erasmus, and then examines its practical application in the Adagia – another sixteenth‐century bestseller – which renders copiousness forth as a physical entity. That work offers the principle of an anthology of all ancient learning, and thus the summation of the bonae litterae. In the process, it provides a model for the problem of how to render the encyclopaedia in literary form.
Managing copiousness for pleasure and profit: William Painter's Palace of Pleasure
Authors: Shinn Abigail
Published: March 2014

This article looks in detail at William Painter's Palace of Pleasure (1566 and 1567), a large two‐volume collection of novella translations and histories, which includes translations of tales by Boccaccio and Bandello. In particular, I analyze some of the textual strategies which ensured the Palace's enduring popularity, specifically Painter's careful wielding of copiousness as a tool for both pleasure and profit. This study focuses primarily on the Palace's paratextual apparatus, from the prefatory rhetoric of the front matter, to the use of architectural metaphors and the organization of textual material via running titles and contents pages. These organizing principles are considered in the light of the reading habits encouraged both by commonplacing and the understanding of reading as having moral effects, in order to identify the Palace as a text which demands that its copious content be actively ‘used’ rather than passively absorbed.
The Ticket to the Soviet Soul: Science, Religion, and the Spiritual Crisis of Late Soviet Atheism
Authors: SMOLKIN‐ROTHROCK VICTORIA
Published: March 2014

This article examines the confrontation of Soviet scientific atheism with religion as it played out on the pages and in the editorial rooms of the country's primary atheist periodical, Nauka i religiia (Science and Religion). It follows a story that begins in the 1960s, when the journal tried to change its title to Mir cheloveka (The World of Man) to reorient itself from the battle against religion towards the battle for Soviet (and therefore atheist) spiritual life. I argue that while the Khrushchev era is the point of origin for much of late Soviet policy on religion and atheism, it is only with the Brezhnev era that we see understandings of religion move beyond ideological stereotypes. New conceptions of religion, however, forced atheists to consider Communist ideology in unexpected (and often troubling) ways, and led to revealing discussions the Soviet state's role in providing spiritual fullness. The story of Nauka i religiia is a microcosm of Soviet ideology in that it reveals the boundaries and contradictions of the material and the spiritual in the Soviet project.
The Power to Promise Oneself
Authors: Fruh Kyle
Published: March 2014

Considerable attention has been devoted to the peculiar obligating force of interpersonal promises. But paradigmatic promising is not an orphan in the family of our moral concepts, and the focus on interpersonal promises has overshadowed sibling phenomena that any account of promises should also cover. I examine the case of single‐party promises and argue, against the prevailing view, that we have good reason to take the phenomenon of making promises to oneself seriously. This supports what I call ‘the breadth criterion’: theoretical accounts of promising should cover the entire breadth of the phenomenon of promising. I then argue that the breadth criterion poses a novel and formidable obstacle for two prominent views of promising, the social practice view and the expectation view. I conclude by suggesting that there is reason to think that the normative power view of promising may fare better.
Sartre and Ricoeur on Productive Imagination
Authors: Levy Lior
Published: March 2014

Commenting on Jean‐Paul Sartre's theory of imagination, Paul Ricoeur argues that Sartre fails to address the productive nature of imaginative acts. According to Ricoeur, Sartre's examples show that he thinks of imagination in mimetic terms, neglecting its innovative and creative dimensions. Imagination, Ricoeur continues, manifests itself most clearly in fiction, wherein new meaning is created. By using fiction as the paradigm of imaginative activity, Ricoeur is able to argue against Sartre that the essence of imagination lies not in its ability to reproduce absent objects, but rather in the ability to transform reality through creative acts. Motivated by the intuition that Sartre the writer could not have forgotten to address such crucial dimensions of imagination, I examine Sartre's philosophical and literary work, showing that not only does he develop a notion of productive imagination, he also puts this notion to work by articulating the relationship between imagination, narrative, and identity formation, well before Ricoeur advanced his narrative‐identity theory. I argue that Sartre, like Ricoeur and MacIntyre, another representative of narrative‐theory whose criticism of Sartre I address in this essay, views imagination and narrativity as necessary conditions for the formation of a coherent and meaningful sense of self.
Moral Imagination, Perception, and Judgment
Authors: Biss Mavis
Published: March 2014

This paper develops an account of moral imagination that identifies the ways in which imaginative capacities contribute to our ability to make reason practical in the world, beyond their roles in moral perception and moral judgment. In section 1, I explain my understanding of what it means to qualify imagination as ‘moral,’ and go on in section 2 to identify four main conceptions of moral imagination as an aspect of practical reason in philosophical ethics. I briefly situate these alternative ideas in relation to standard accounts of moral perception and judgment with reference to some guiding examples. In section 3, I argue that the fourth conception of moral imagination, moral imagination understood as the capacity to generate new possibilities for morally good action, is not well accounted for within the standard categories of practical reason. Section 4 clarifies the scope and importance of this capacity and defends its claim to increased theoretical attention.
Allogeneic versus autologous blood transfusion and survival after radical prostatectomy (CME)
Authors: Chalfin Heather J. , Frank Steven M. , Feng Zhaoyong , Trock Bruce J. , Drake Charles G. , Partin Alan W. , Humphreys Elizabeth , Ness Paul M. , Jeong Byong C. , Lee Seung B. , Han Misop
Published: March 2014

Background

Potential adverse effects of blood transfusion (BT) remain controversial, especially for clinical outcomes after curative cancer surgery. Some postulate that immune modulation after allogeneic BT predisposes to recurrence and death, but autologous superiority is not established. This study assessed whether BT is associated with long‐term prostate cancer recurrence and survival with a large single‐institutional radical prostatectomy (RP) database.

Study Design and Methods

Between 1994 and 2012, a total of 11,680 patients had RP with available outcome and transfusion data. A total of 7443 (64%) had complete covariate data. Clinical variables associated with biochemical recurrence‐free survival (BRFS), cancer‐specific survival (CSS), and overall survival (OS) were identified with Cox proportional hazards models for three groups: no BT (reference, 27.7%, n = 2061), autologous BT only (68.8%, n = 5124), and any allogeneic BT (with or without autologous, 3.5%, n = 258).

Results

Median (range) follow‐up was 6 (1‐18) years. Kaplan‐Meier analysis showed significantly decreased OS (but not BRFS or PCSS) in the allogeneic group versus autologous and no BT groups (p = 0.006). With univariate analysis, any allogeneic BT had a hazard ratio (HR) of 2.29 (range, 1.52‐3.46; p < 0.0001) for OS, whereas autologous BT was not significant (HR, 1.04 [range, 0.82‐1.32], p = 0.752). In multivariable models, neither autologous nor allogeneic BT was independently associated with BRFS, CSS, or OS, and a dose response was not observed for allogeneic units and BRFS.

Conclusion

Although allogeneic but not autologous BT was associated with decreased long‐term OS, after adjustment for confounding clinical variables, BT was not independently associated with OS, BRFS, or CSS regardless of transfusion type. Notably, no association was observed between allogeneic BT and cancer recurrence. Observed differences in OS may reflect confounding.
Experimental Investigation on Fiber Thermocouples Used in Brush Seals for Temperature Measurements
Authors: Huang Shouqing , Suo Shuangfu , Li Yongjian , Ding Jun , Wang Yuming
Published: March 2014

A type of fiber thermocouple is applied to a brush seal in order to obtain the temperature of the bristle-rotor friction zone. Using a brush seal test rig, the temperature measurements utilizing a fiber thermocouple, infrared thermometer, and common thermocouple are compared and studied. The fiber thermocouple is studied under various operational conditions consisting of different pressure and speed variations, rotor-bristle interferences, and eccentricities. Some interesting phenomena and characteristics of brush seals are revealed during these experiments. Some preliminary wear results of a fiber thermocouple are also presented. The results demonstrate the superiority of fiber thermocouples when used in narrow spaces, high temperature, and pressure environments within the heart of an aero-engine.
Variable Fin Density Flow Channels for Effective Cooling and Mitigation of Temperature Nonuniformity in Three-Dimensional Integrated Circuits
Authors: Lorenzini-Gutierrez Daniel , Kandlikar Satish G.
Published: March 2014

The surface temperature of integrated circuit (IC) chips cooled with a single-phase liquid flow increases along the flow direction following the increase in the liquid temperature. Increasing the heat transfer coefficient along the flow direction is an effective way to enhance the cooling performance while mitigating the temperature nonuniformity and high pressure drop concerns. This investigation evaluates numerically the cooling performance of different flow channel designs suitable in 3D IC applications with channel heights restricted to 100 μm. Internal configurations featuring offset strip fins with variable fin density and variable spacing ribs were studied in an effort to minimize the temperature nonuniformity while maintaining a relatively low pressure drop. The performance of 13 different designs for the variable-fin-density configuration and three different rib configurations have been evaluated and compared with two baseline cases, corresponding to a smooth flow channel and a flow channel with continuous fins. All of the analyzed internal configurations are contained within a flow channel of 100 μm height and 910 μm width. A coolant chip formed by nine flow channels for the dissipation of 200 W of a 3D IC with a surface area of 1 cm2 is the base for this investigation. The best performing configuration resulted in a temperature variation of less than 30 K with a pressure drop of 34 kPa as compared to a temperature variation of 38 K and a pressure drop of 144 kPa with continuous fins and 51 K and 21 kPa for a smooth flow channel.
Characterizing the Hemming Performance of Automotive Aluminum Alloys With High-Resolution Topographic Imaging
Authors: Stoudt M. R. , Hubbard J. B. , Carsley J. E. , Hartfield-Wünsch S. E.
Published: March 2014

We used high-resolution quantitative surface analysis to evaluate the surfaces of two aluminum automotive closure panel alloys, which were bent to a 180 deg angle in a simulated hemming test. Maps of the displacements normal to the sheet were superimposed on the topographies to correlate the location of the maximum displacements and the surface morphology. While the alloys had similar mechanical properties, quantitative analyses yielded considerable differences in the deformed surface morphologies. One alloy had a greater density and broader size distribution of constituent particles, which increased the likelihood for particle decohesion. This resulted in large surface displacements that were uncorrelated with the underlying microstructure. While no splitting was observed in either alloy, large uncorrelated surface displacements could indicate the presence of short surface cracks.
A Fundamental Study and Modeling of the Micro-Droplet Formation Process in Near-Field Electrohydrodynamic Jet Printing
Authors: Carter William , Popell George C. , Samuel Johnson , Mishra Sandipan
Published: March 2014

Near-field electrohydrodynamic jet (E-jet) printing has recently gained significant interest within the manufacturing research community because of its ability to produce micro/submicron-scale droplets using a wide variety of inks and substrates. However, the process currently operates in open-loop and as a result suffers from unpredictable printing quality. The use of physics-based, control-oriented process models is expected to enable closed-loop control of this printing technique. The objective of this research is to perform a fundamental study of the substrate-side droplet shape-evolution in near-field E-jet printing and to develop a physics-based model of the same that links input parameters such as voltage magnitude and ink properties to the height and diameter of the printed droplet. In order to achieve this objective, a synchronized high-speed imaging and substrate-side current-detection system is implemented to enable a correlation between the droplet shape parameters and the measured current signal. The experimental data reveals characteristic process signatures and droplet spreading regimes. The results of these studies served as the basis for a model that uses the measured current signal as its input to predict the final droplet diameter and height. A unique scaling factor based on the measured current signal is used in this model instead of relying on empirical scaling laws found in prior E-jet literature. For each of the three inks tested in this study, the average error in the model predictions is under 10% for both the diameter and the height of the steady-state droplet. While printing under nonconducive ambient conditions of low relative humidity and high temperature, the use of the environmental correction factor in the model is seen to result in a 17% reduction in the model prediction error.
Fast Generation of Micro-Channels on Cylindrical Surfaces by Elliptical Vibration Texturing
Authors: Guo Ping , Lu Yong , Pei Pucheng , Ehmann Kornel F.
Published: March 2014

Micro-structured surfaces are assuming an ever-increasing role since they define the ultimate performance of many industrial components and products. Micro-channels, in particular, have many potential applications in micro-fluidic devices, micro heat exchangers, and friction control. This paper proposes an innovative vibration-assisted machining method to generate micro-channels on the external surface of a cylinder. This method, referred to as elliptical vibration texturing, was originally developed by the authors to generate dimple patterns. It uses the modulation of the depth-of-cut by tool vibrations to create surface textures. The most promising features of the proposed method are its high efficiency, low cost, and scalability for mass production. It is shown that with proper combinations of the process parameters the created dimples start to overlap and form channels. An analytical model is established to predict channel formation with respect to the overlapping ratios of the dimples. Channel formation criteria and expressions for channel geometries are given along with a channel generation map that relates channel geometry to the process parameters. Experimental results are given to verify the model. A further example of micro-pattern generation is also given to showcase the flexibility of the process.
Fast Dispersive Laser Scanner by Using Digital Micro Mirror Arrays
Authors: Kalyoncu Salih K. , Torun Rasul , Huang Yuewang , Zhao Qiancheng , Boyraz Ozdal
Published: March 2014

We demonstrate a fast dispersive laser scanning system by using MEMS digital micro-mirror arrays technology. The proposed technique utilizes real-time dispersive imaging system, which captures spectrally encoded images with a single photodetector at pulse repetition rate via space-to-time mapping technology. Wide area scanning capability is introduced by using individually addressable micro-mirror arrays as a beam deflector. Experimentally, we scanned ∼20 mm2 at scan rate of 5 kHz with ∼150 μm lateral and ∼160 μm vertical resolution that can be controlled by using 1024 × 768 mirror arrays. With the current state of art MEMS technology, fast scanning with <30 μs and resolution down to single mirror pitch size of 10.8 μm is also achievable.
Piezoelectric Shunt Vibration Damping of Structural-Acoustic Systems: Finite Element Formulation and Reduced-Order Model
Authors: Deü Jean-François , Larbi Walid , Ohayon Roger , Sampaio Rubens
Published: March 2014

For noise and vibration attenuation, various approaches can be employed depending on the frequency range to attenuate. Generally, active or passive piezoelectric techniques are effective in the low-frequency range, while dissipative materials, such as viscoelastic or porous treatments, are efficient for higher-frequency domain. In this work, a reduced-order model is developed for the approximation of a fully coupled electromechanical-acoustic system using modal projection techniques. The problem consists of an elastic structure with surface-mounted piezoelectric patches coupled with a compressible inviscid fluid. The piezoelectric elements, connected with resonant shunt circuits, are used for the vibration damping of the coupled system. Numerical examples are presented in order to illustrate the accuracy and the versatility of the proposed reduced-order model, especially in terms of prediction of attenuation.
Characterization of dental interfaces with electron tomography
Authors: Grandfield Kathryn , Engqvist Håkan
Published: March 2014

Understanding the interface between dental materials and tooth is critical in the prevention of secondary caries. Assessing this interface with high-resolution clarity has traditionally been challenging. This work highlights electron tomography, carried out in the transmission electron microscope, as a novel technique to obtain both three-dimensional and nanometer scaled information on dental materials in contact with dentin. In this study, commercial calcium aluminate and glass ionomer based luting agents in contact with human dentin were prepared for electron microscopy via focused ion beam milling. Imaging with high-angle annular dark field provided compositional contrast, and combined with tilting over large angular ranges, enabled the reconstruction of the three-dimensional interface between tissue and cement. The characteristics of the interface were observed with this extra dimensionality and superior resolution, providing evidence for the viability of this technique in interfacial studies of dental materials.
Portable total reflection x-ray fluorescence analysis in the identification of unknown laboratory hazards
Authors: Liu Ying , Imashuku Susumu , Sasaki Nobuharu , Ze Long , Kawai Jun , Takano Shotaro , Sohrin Yoshiki , Seki Hiroko , Miyauchi Hiroya
Published: March 2014

In this study, a portable total reflection x-ray fluorescence (TXRF) spectrometer was used to analyze unknown laboratory hazards that precipitated on exterior surfaces of cooling pipes and fume hood pipes in chemical laboratories. With the aim to examine the accuracy of TXRF analysis for the determination of elemental composition, analytical results were compared with those of wavelength-dispersive x-ray fluorescence spectrometry, scanning electron microscope and energy-dispersive x-ray spectrometry, energy-dispersive x-ray fluorescence spectrometry, inductively coupled plasma atomic emission spectrometry, x-ray diffraction spectrometry (XRD), and x-ray photoelectron spectroscopy (XPS). Detailed comparison of data confirmed that the TXRF method itself was not sufficient to determine all the elements (Z > 11) contained in the samples. In addition, results suggest that XRD should be combined with XPS in order to accurately determine compound composition. This study demonstrates that at least two analytical methods should be used in order to analyze the composition of unknown real samples.
Influencing factors on the sensitivity of MEMS-based thermal conductivity vacuum gauges
Authors: Dams Florian , Schreiner Rupert
Published: March 2014

The measurement range of thermal conductivity vacuum gauges is mainly influenced by the sensitivity of the sensing element to variations in pressure. An enhanced definition of sensitivity shows its theoretical dependence on the geometric measures of the sensor element at the whole pressure range. This value gives the possibility of direct comparison between different types of sensor structures without the influence of the operating conditions. To study the influencing factors, sensor chips with heated surfaces in the order of some tens of mm2 were realized by microelectromechanical systems-based fabrication techniques. By a silicon-glass hybrid process two cold planes were formed in a distance of 150 μm above and below the heated element. The thermal conductance of devices with different geometric measures was determined in constant temperature operating mode by usage of embedded measurement equipment. In this configuration the sensor signals were sensitive to pressure in a region from 10−5 mbar. The sensitivity was extracted by a fit of the theoretical model to the measurement data and showed the predicted dependencies on the geometric measures.
Effect of WN content on toughness enhancement in V1−xWxN/MgO(001) thin films
Authors: Kindlund H. , Sangiovanni D. G. , Lu J. , Jensen J. , Chirita V. , Petrov I. , Greene J. E. , Hultman L.
Published: March 2014

The authors report the growth and mechanical properties of epitaxial B1 NaCl-structure V1−xWxN/MgO(001) thin films with 0 ≤ x ≤ 0.60. The Gibbs free energy of mixing, calculated using density functional theory (DFT), reveals that cubic V1−xWxN solid solutions with 0 ≤ x ≲ 0.7 are stable against spinodal decomposition and separation into the equilibrium cubic-VN and hexagonal-WN binary phases. The authors show experimentally that alloying VN with WN leads to a monotonic increase in relaxed lattice parameters, enhanced nanoindentation hardnesses, and reduced elastic moduli. Calculated V1−xWxN lattice parameters and elastic moduli (obtained from calculated C11, C12, and C44 elastic constants) are in good agreement with experimental results. The observed increase in alloy hardness, with a corresponding decrease in the elastic modulus at higher x values, combined with DFT-calculated decreases in shear to bulk moduli ratios, and increased Cauchy pressures (C12–C44) with increasing x reveal a trend toward increased toughness.
Symmetric interactions and interference between pitch and timbre
Authors: Allen Emily J. , Oxenham Andrew J.
Published: March 2014

Variations in the spectral shape of harmonic tone complexes are perceived as timbre changes and can lead to poorer fundamental frequency (F0) or pitch discrimination. Less is known about the effects of F0 variations on spectral shape discrimination. The aims of the study were to determine whether the interactions between pitch and timbre are symmetric, and to test whether musical training affects listeners' ability to ignore variations in irrelevant perceptual dimensions. Difference limens (DLs) for F0 were measured with and without random, concurrent, variations in spectral centroid, and vice versa. Additionally, sensitivity was measured as the target parameter and the interfering parameter varied by the same amount, in terms of individual DLs. Results showed significant and similar interference between pitch (F0) and timbre (spectral centroid) dimensions, with upward spectral motion often confused for upward F0 motion, and vice versa. Musicians had better F0DLs than non-musicians on average, but similar spectral centroid DLs. Both groups showed similar interference effects, in terms of decreased sensitivity, in both dimensions. Results reveal symmetry in the interference effects between pitch and timbre, once differences in sensitivity between dimensions and subjects are controlled. Musical training does not reliably help to overcome these effects.
Intelligibility of time-compressed speech: The effect of uniform versus non-uniform time-compression algorithms
Authors: Schlueter Anne , Lemke Ulrike , Kollmeier Birger , Holube Inga
Published: March 2014

For assessing hearing aid algorithms, a method is sought to shift the threshold of a speech-in-noise test to (mostly positive) signal-to-noise ratios (SNRs) that allow discrimination across algorithmic settings and are most relevant for hearing-impaired listeners in daily life. Hence, time-compressed speech with higher speech rates was evaluated to parametrically increase the difficulty of the test while preserving most of the relevant acoustical speech cues. A uniform and a non-uniform algorithm were used to compress the sentences of the German Oldenburg Sentence Test at different speech rates. In comparison, the non-uniform algorithm exhibited greater deviations from the targeted time compression, as well as greater changes of the phoneme duration, spectra, and modulation spectra. Speech intelligibility for fast Oldenburg sentences in background noise at different SNRs was determined with 48 normal-hearing listeners. The results confirmed decreasing intelligibility with increasing speech rate. Speech had to be compressed to more than 30% of its original length to reach 50% intelligibility at positive SNRs. Characteristics influencing the discrimination ability of the test for assessing effective SNR changes were investigated. Subjective and objective measures indicated a clear advantage of the uniform algorithm in comparison to the non-uniform algorithm for the application in speech-in-noise tests.
Cochleagram-based audio pattern separation using two-dimensional non-negative matrix factorization with automatic sparsity adaptation
Authors: Gao Bin , Woo W. L. , Khor L. C.
Published: March 2014

An unsupervised single channel audio separation method from pattern recognition viewpoint is presented. The proposed method does not require training knowledge and the separation system is based on non-uniform time-frequency (TF) analysis and feature extraction. Unlike conventional research that concentrates on the use of spectrogram or its variants, the proposed separation algorithm uses an alternative TF representation based on the gammatone filterbank. In particular, the monaural mixed audio signal is shown to be considerably more separable in this non-uniform TF domain. The analysis of signal separability to verify this finding is provided. In addition, a variational Bayesian approach is derived to learn the sparsity parameters for optimizing the matrix factorization. Experimental tests have been conducted, which show that the extraction of the spectral dictionary and temporal codes is more efficient using sparsity learning and subsequently leads to better separation performance.
Expansions for infinite or finite plane circular time-reversal mirrors and acoustic curtains for wave-field-synthesis
Authors: Mellow Tim , Kärkkäinen Leo
Published: March 2014

An acoustic curtain is an array of microphones used for recording sound which is subsequently reproduced through an array of loudspeakers in which each loudspeaker reproduces the signal from its corresponding microphone. Here the sound originates from a point source on the axis of symmetry of the circular array. The Kirchhoff-Helmholtz integral for a plane circular curtain is solved analytically as fast-converging expansions, assuming an ideal continuous array, to speed up computations and provide insight. By reversing the time sequence of the recording (or reversing the direction of propagation of the incident wave so that the point source becomes an “ideal” point sink), the curtain becomes a time reversal mirror and the analytical solution for this is given simultaneously. In the case of an infinite planar array, it is demonstrated that either a monopole or dipole curtain will reproduce the diverging sound field of the point source on the far side. However, although the real part of the sound field of the infinite time-reversal mirror is reproduced, the imaginary part is an approximation due to the missing singularity. It is shown that the approximation may be improved by using the appropriate combination of monopole and dipole sources in the mirror.
External and middle ear sound pressure distribution and acoustic coupling to the tympanic membrane
Authors: Bergevin Christopher , Olson Elizabeth S.
Published: March 2014

Sound energy is conveyed to the inner ear by the diaphanous, cone-shaped tympanic membrane (TM). The TM moves in a complex manner and transmits sound signals to the inner ear with high fidelity, pressure gain, and a short delay. Miniaturized sensors allowing high spatial resolution in small spaces and sensitivity to high frequencies were used to explore how pressure drives the TM. Salient findings are: (1) A substantial pressure drop exists across the TM, and varies in frequency from ∼10 to 30 dB. It thus appears reasonable to approximate the drive to the TM as being defined solely by the pressure in the ear canal (EC) close to the TM. (2) Within the middle ear cavity (MEC), spatial variations in sound pressure could vary by more than 20 dB, and the MEC pressure at certain locations/frequencies was as large as in the EC. (3) Spatial variations in pressure along the TM surface on the EC-side were typically less than 5 dB up to 50 kHz. Larger surface variations were observed on the MEC-side.
The effect of vowel inventory and acoustic properties in Salento Italian learners of Southern British English vowels
Authors: Escudero Paola , Sisinni Bianca , Grimaldi Mirko
Published: March 2014

Salento Italian (SI) listeners' categorization and discrimination of standard Southern British English (SSBE) vowels were examined in order to establish their initial state in the acquisition of the SSBE vowel system. The results of the vowel categorization task revealed that SI listeners showed single-category assimilation for many SSBE vowels and multiple-category assimilation for others. Additionally, SI vowel discrimination accuracy varied across contrasts, in line with the categorization results. This differential level of difficulty is discussed on the basis of current L2 perception models. The SI categorization results were then compared to the previously reported data on Peruvian Spanish (PS) listeners. Both SI and PS have a five-vowel inventory and therefore both listener groups were expected to have similar problems when distinguishing SSBE vowel contrasts, but were predicted to have different mappings of SSBE vowels to native categories due to the differences in the acoustic properties of vowels across the two languages. As predicted by the hypothesis that acoustic differences in production lead to a different nonnative perception, the comparison showed that there was large variability in how SSBE vowels are initially mapped to the specific five-vowel inventory. Predictions for differential L2 development across languages are also provided.
Towards undistorted and noise-free speech in an MRI scanner: Correlation subtraction followed by spectral noise gating
Authors: Inouye Joshua M. , Blemker Silvia S. , Inouye David I.
Published: March 2014

Noise cancellation in an MRI environment is difficult due to the high noise levels that are in the spectral range of human speech. This paper describes a two-step method to cancel MRI noise that combines operations in both the time domain (correlation subtraction) and the frequency domain (spectral noise gating). The resulting filtered recording has a noise power suppression of over 100 dB, a significant improvement over previously described techniques on MRI noise cancellation. The distortion is lower and the noise suppression higher than using spectral noise gating in isolation. Implementation of this method will aid in detailed studies of speech in relation to vocal tract and velopharyngeal function.
Green's function retrieval through cross-correlations in a two-dimensional complex reverberating medium
Authors: Colombi Andrea , Boschi Lapo , Roux Philippe , Campillo Michel
Published: March 2014

Cross-correlations of ambient noise averaged at two receivers lead to the reconstruction of the two-point Green's function, provided that the wave-field is uniform azimuthally, and also temporally and spatially uncorrelated. This condition depends on the spatial distribution of the sources and the presence of heterogeneities that act as uncorrelated secondary sources. This study aims to evaluate the relative contributions of source distribution and medium complexity in the two-point cross-correlations by means of numerical simulations and laboratory experiments in a finite-size reverberant two-dimensional (2D) plate. The experiments show that the fit between the cross-correlation and the 2D Green's function depends strongly on the nature of the source used to excite the plate. A turbulent air-jet produces a spatially uncorrelated acoustic field that rapidly builds up the Green's function. On the other hand, extracting the Green's function from cross-correlations of point-like sources requires more realizations and long recordings to balance the effect of the most energetic first arrivals. When the Green's function involves other arrivals than the direct wave, numerical simulations confirm the better Green's function reconstruction with a spatially uniform source distribution than the typical contour-like source distribution surrounding the receivers that systematically gives rise to spurious phases.
Effects of interferer facing orientation on speech perception by normal-hearing and hearing-impaired listeners
Authors: Strelcyk Olaf , Pentony Shareka , Kalluri Sridhar , Edwards Brent
Published: March 2014

There exist perceptible differences between sound emanating from a talker who faces and a talker who does not face a listener: Sound from a non-facing talker is attenuated and acquires a spectral tilt. The present study assessed the role that these facing-orientation cues play for speech perception. Digit identification for a frontal target talker in the presence of two spatially separated interfering talkers was measured for 10 normal-hearing (NH) and 11 hearing-impaired (HI) listeners. Overall-level differences and spectral tilts were reproduced by means of digital filtering and playback via loudspeakers. Both NH and HI listeners performed significantly better when the interfering talkers were simulated not to be facing them. Spectral tilts and level differences across talkers reduced target-interferer confusions. They enabled the NH listeners to sequentially stream the digits. This was not the case for the HI listeners, who showed smaller benefits, irrespective of whether they were aided by their own hearing aids or not. While hearing-aid amplification increased audibility, it may not have aided target-interferer segregation or target selection. The present results suggest that facing orientation cannot be neglected in the exploration of speech perception in multitalker situations.
The effects of rhythm and melody on auditory stream segregation
Authors: Szalárdy Orsolya , Bendixen Alexandra , Böhm Tamás M. , Davies Lucy A. , Denham Susan L. , Winkler István
Published: March 2014

While many studies have assessed the efficacy of similarity-based cues for auditory stream segregation, much less is known about whether and how the larger-scale structure of sound sequences support stream formation and the choice of sound organization. Two experiments investigated the effects of musical melody and rhythm on the segregation of two interleaved tone sequences. The two sets of tones fully overlapped in pitch range but differed from each other in interaural time and intensity. Unbeknownst to the listener, separately, each of the interleaved sequences was created from the notes of a different song. In different experimental conditions, the notes and/or their timing could either follow those of the songs or they could be scrambled or, in case of timing, set to be isochronous. Listeners were asked to continuously report whether they heard a single coherent sequence (integrated) or two concurrent streams (segregated). Although temporal overlap between tones from the two streams proved to be the strongest cue for stream segregation, significant effects of tonality and familiarity with the songs were also observed. These results suggest that the regular temporal patterns are utilized as cues in auditory stream segregation and that long-term memory is involved in this process.
Molecular Gas Clumps from the Destruction of Icy Bodies in the β Pictoris Debris Disk
Authors: Dent W. R. F. , Wyatt M. C. , Roberge A. , Augereau J.-C. , Casassus S. , Corder S. , Greaves J. S. , de Gregorio-Monsalvo I. , Hales A. , Jackson A. P. , Hughes A. Meredith , Lagrange A.-M. , Matthews B. , Wilner D.
Published: March 2014

One-Sided Story from Disk

In young analogs of the solar system, the ongoing erosion of comets and nascent planets produces dusty debris that is eventually expelled by the host star. Gas should also be released in this process when volatile ices sublimate, but it is detected less often. Using the Atacama Large Millimeter/Submillimeter Array,

Dent
et al.

(p.
1490
, published online 6 March; see the Perspective by

Brandeker

) mapped a highly asymmetric disk of dust and carbon monoxide orbiting the planet-hosting star, β Pictoris. The distribution of gas and dust is consistent with two proposed scenarios: In one, an outward-migrating planet has resonantly trapped dust-yielding bodies in two clumps opposite the star. In another, the entire debris mass is the result of a single recent collision of Mars-sized bodies.
Dynamic Reorganization of River Basins
Authors: Willett Sean D. , McCoy Scott W. , Perron J. Taylor , Goren Liran , Chen Chia-Yu
Published: March 2014

Introduction

River networks, the backbone of most landscapes on Earth, collect and transport water, sediment, organic matter, and nutrients from upland mountain regions to the oceans. Dynamic aspects of these networks include channels that shift laterally or expand upstream, ridges that migrate across Earth’s surface, and river capture events whereby flow from one branch of the network is rerouted in a new direction. These processes result in a constantly changing map of the network with implications for mass transport and the geographic connectivity between species or ecosystems. Ultimately, this dynamic system strives to establish equilibrium between tectonic uplift and river erosion. Determining whether or not a river network is in equilibrium, and, if not, what changes are required to bring it to equilibrium, will help us understand the processes underlying landscape evolution and the implications for river ecosystems.

Methods

We developed the use of a proxy, referred to as χ, for steady-state river channel elevation. This proxy is based on the current geometry of the river network and provides a snapshot of the dynamic state of river basins. Geometric equilibrium in planform requires that a network map of χ exhibit equal values across all water divides (the ridges separating river basins). Disequilibrium river networks adjust their drainage area through divide migration (geometric change) or river capture (topologic change) until this condition is met. We constructed a numerical model to demonstrate that this is a fundamental characteristic of a stable river network. We applied this principle to natural landscapes using digital elevation models to calculate χ for three, very different, systems: the Loess Plateau in China, the eastern Central Range of Taiwan, and the southeastern United States.

Results

The Loess Plateau is close to geometric equilibrium, with χ exhibiting nearly equal values across water divides. By contrast, the young and tectonically active Taiwan mountain belt is not in equilibrium, with numerous examples of actively migrating water divides and river network reorganization. The southeastern United States also appears to be far from equilibrium, with the Blue Ridge escarpment migrating to the northwest and the coastal plain rivers reorganizing in response to this change in boundary geometry. Major reorganization events, such as the capture of the headwaters of the Apalachicola River by the Savannah River, are readily identifiable in our maps.

Discussion

Disequilibrium conditions in a river network imply greater variation of weathering, soil production, and erosion rates. Disequilibrium also implies more frequent river capture with implications for exchange of aquatic species and genetic diversification. Transient conditions in river basins are often interpreted in terms of tectonic perturbation, but our results show that river basin reorganization can occur even in tectonically quiescent regions such as the southeastern United States.
Culturing the Forest
The Social Lives of Forests
Past, Present, and Future of Woodland Resurgence

Susanna B. Hecht, Kathleen D. Morrison, and Christine Padoch, Eds.

University of Chicago Press, Chicago, 2014. 507 pp. $50, £35. ISBN 9780226322667.
Authors: Plieninger Tobias
Published: March 2014

Examining the widespread resurgence of woodlands, the authors build a multifaceted view of forests as social-ecological systems.