1,510 research outputs found
Imaging compaction band propagation in Diemelstadt sandstone using acoustic emission locations
We report results from a conventional triaxial test performed on a specimen of Diemelstadt sandstone under an effective confining pressure of 110 MPa; a value sufficient to induce compaction bands. The maximum principal stress was applied normal to the visible bedding so that compaction bands propagated parallel to bedding. The spatio-temporal distribution of acoustic emission events greater than 40 dB in amplitude, and associated with the propagation of the first compaction band, were located in 3D, to within +/- 2 mm, using a Hyperion Giga-RAM recorder. Event magnitudes were used to calculate the seismic b- value at intervals during band growth. Results show that compaction bands nucleate at the specimen edge and propagate across the sample at approximately 0.08 mm s(-1). The seismic b-value does not vary significantly during deformation, suggesting that compaction band growth is characterized by small scale cracking that does not change significantly in scale
Perceptual restoration of masked speech in human cortex
Humans are adept at understanding speech despite the fact that our natural listening environment is often filled with interference. An example of this capacity is phoneme restoration, in which part of a word is completely replaced by noise, yet listeners report hearing the whole word. The neurological basis for this unconscious fill-in phenomenon is unknown, despite being a fundamental characteristic of human hearing. Here, using direct cortical recordings in humans, we demonstrate that missing speech is restored at the acoustic-phonetic level in bilateral auditory cortex, in real-time. This restoration is preceded by specific neural activity patterns in a separate language area, left frontal cortex, which predicts the word that participants later report hearing. These results demonstrate that during speech perception, missing acoustic content is synthesized online from the integration of incoming sensory cues and the internal neural dynamics that bias word-level expectation and prediction
Spatial knowledge management and participatory governance: rethinking the trajectories of urban, socio-economic and environmental change and the politics of 'sustainability' in southern cities
This paper presents the analytical framework developed iteratively by the research team of the Chance2Sustain (C2S) research project between 2010 and July 2014, in order to answer the main research question which was posed at the outset of the research, namely : how can spatial knowledge management (SKM) and participatory governance contribute to sustainable urban development ? To answer this question, the C2S project was designed to undertake comparative empirical research in 10 cities in four fast-growing countries of the South to understand the role of SKM and participatory processes in facing the challenges in a number of strategic domains of urban development ; those of economic growth, social inequality and vulnerability, and environmental governance. In each city, there were researchers from both the North and South working together in the five domains of economic growth through megaprojects ; social mobilisation and social exclusion in sub-standard settlements ; environmental governance with the focus on water-related issues ; spatial knowledge management; and fiscal decentralisation and participatory city budgeting
Polarization properties of OH masers in AGB and post-AGB stars
Context: Ground-state OH maser emission from late-type stars is usually
polarized and remains a powerful probe of the magnetic field structure in the
outer regions of circumstellar envelopes if observed with high angular and
spectral resolutions. Observations in all four Stokes parameters are quite
sparse and this is the most thorough, systematic study published to date.
Aims: We aim to determine polarization properties of OH masers in an
extensive sample of stars that show copious mass loss and search for candidate
objects that are well-suited for high angular resolution studies.
Methods: Full-polarization observations of the OH 1612 and 1667 MHz maser
transitions were carried out for a sample of 117 AGB and post-AGB stars.
Several targets were also observed in the 1665 MHz line.
Results: Polarized features occur in more than 75% of the sources in the
complete sample and there is no intrinsic difference in the occurrence of
polarized emission between the three classes of objects of different infrared
characteristics. The highest fractional polarization occurs for the post-AGB+PN
and the Mira+SR classes at 1612 and 1667 MHz, respectively. Differences in the
fractional polarization between the sources at different evolutionary stages
appear to be related to depolarization caused by blending. The alignment of the
polarization angles at the extreme sides of the shell implies a regular
structure of the magnetic field of a strength of 0.3-2.3 mG.
Conclusions: Polarized OH maser features are widespread in AGB and post-AGB
stars. The relationship between the circular and linear fractional
polarizations for a representative sample are consistent with the standard
models of polarization for the Zeeman splitting higher than the Doppler line
width, whereas the polarized features are the sigma components.Comment: Accepted for publication in Astronomy and Astrophysics. A version
with appendices (Tab. A.1 and Fig. B.1) can be downloaded from
http://paulo.astro.uni.torun.pl/~pw/arXiv_
Les transformations paysagères de la plaine du Rhône : Analyse diachronique et cartographie historique (1840-2010)
National audienceCet article vise deux objectifs. D’une part, il présente une cartographie et desstatistiques sur l’évolution de la plaine entre 1840 et 2005; d’autre part, il étudieplus en détail la question de l’assèchement de la plaine et de la progressive disparitiondes zones humides. Le texte est organisé en trois parties. Dans un premiertemps, nous présentons les caractéristiques méthodologiques de l’approche géohistorique;dans un deuxième temps, nous analysons la plaine selon cinq états de référence(1840, 1880, 1920, 1965, 2005); la troisième partie se penche sur l’assèchementprogressif des zones marécageuses de la plain
Effect of gestational age at birth on neonatal outcomes in gastroschisis.
Induced birth of fetuses with gastroschisis from 34weeks gestational age (GA) has been proposed to reduce bowel damage. We aimed to determine the effect of birth timing on time to full enteral feeds (ENT), length of hospital stay (LOS), and sepsis.
A retrospective analysis (2000-2014) of gastroschisis born at ≥34weeks GA was performed. Associations between birth timing and outcomes were analyzed by Mann-Whitney test, Cox regression, and Fisher's exact test.
217 patients were analyzed. Although there was no difference in ENT between those born at 34-36+6weeks GA (median 28 range [6-639] days) compared with ≥37weeks GA (27 [8-349] days) when analyzed by Mann-Whitney test (p=0.5), Cox regression analysis revealed that lower birth GA significantly prolonged ENT (p=0.001). LOS was significantly longer in those born at 34-36+6weeks GA (42 [8-346] days) compared with ≥37weeks GA 34 [11-349] days by both Mann-Whitney (p=0.02) and Cox regression analysis (p<0.0005). Incidence of sepsis was higher in infants born at 34-36+6weeks (32%) vs. infants born at ≥37weeks (17%; p=0.02).
Early birth of fetuses with gastroschisis was associated with delay in reaching full enteral feeds, prolonged hospitalization, and a higher incidence of sepsis
Кон'юнктурний аналіз розвитку ринку рекреаційних послуг АР Крим
Метою дослідження є кон’юнктурний аналіз розвитку ринку рекреаційних послуг АР Крим та порівняльна оцінка функціонування конкурентоспроможних рекреаційних районів
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