14,998 research outputs found
Energy and Momentum of a Class of Rotating Gravitational Waves
We calculate energy and momentum for a class of cylindrical rotating
gravitational waves using Einstein and Papapetrou's prescriptions. It is shown
that the results obtained are reduced to the special case of the cylindrical
gravitational waves already available in the literature.Comment: 11 pages, no figure, Late
Nonet Symmetry and Two-Body Decays of Charmed Mesons
The decay of charmed mesons into pseudoscalar (P) and vector (V) mesons is
studied in the context of nonet symmetry. We have found that it is badly broken
in the PP channels and in the P sector of the PV channels as expected from the
non-ideal mixing of the \eta and the \eta'. In the VV channels, it is also
found that nonet symmetry does not describe the data well. We have found that
this discrepancy cannot be attributed entirely to SU(3) breaking at the usual
level of 20--30%. At least one, or both, of nonet and SU(3) symmetry must be
very badly broken. The possibility of resolving the problem in the future is
also discussed.Comment: 9 pages, UTAPHY-HEP-
Energy-momentum Density of Gravitational Waves
In this paper, we elaborate the problem of energy-momentum in general
relativity by energy-momentum prescriptions theory. Our aim is to calculate
energy and momentum densities for the general form of gravitational waves. In
this connection, we have extended the previous works by using the prescriptions
of Bergmann and Tolman. It is shown that they are finite and reasonable. In
addition, using Tolman prescription, exactly, leads to same results that have
been obtained by Einstein and Papapetrou prescriptions.Comment: LaTeX, 9 pages, 1 table: added reference
Sufficient conditions for the existence of Q-balls in gauge theories
We formulate a set of simple sufficient conditions for the existence of
Q-balls in gauge theories.Comment: 5 page
The role of source and filter cues in emotion recognition in speech [Abstract]
In the context of the source-filter theory of speech, it is well established that intelligibility is heavily reliant on information carried by the filter, that is, spectral cues (e.g., Faulkner et al., 2001; Shannon et al., 1995). However, the extraction of other types of information in the speech signal, such as emotion and identity, is less well understood. In this study we investigated the extent to which emotion recognition in speech depends on filterdependent cues, using a forced-choice emotion identification task at ten levels of noise-vocoding ranging between one and 32 channels. In addition, participants performed a speech intelligibility task with the same stimuli. Our results indicate that compared to speech intelligibility, emotion recognition relies less on spectral information and more on cues typically signaled by source variations, such as voice pitch, voice quality, and intensity. We suggest that, while the reliance on spectral dynamics is likely a unique aspect of human speech, greater phylogenetic continuity across species may be found in the communication of affect in vocalizations
ORFEUS II and IUE Spectroscopy of EX Hydrae
Using ORFEUS-SPAS II FUV spectra, IUE UV spectra, and archival EUVE deep
survey photometry, we present a detailed picture of the behavior of the
magnetic cataclysmic variable EX Hydrae. Like HUT spectra of this source, the
FUV and UV spectra reveal broad emission lines of He II, C II-IV, N III and V,
O VI, Si III-IV, and Al III superposed on a continuum which is blue in the UV
and nearly flat in the FUV. Like ORFEUS spectra of AM Her, the O VI doublet is
resolved into broad and narrow emission components. Consistent with its
behavior in the optical, the FUV and UV continuum flux densities, the FUV and
UV broad emission line fluxes, and the radial velocity of the O VI broad
emission component all vary on the spin phase of the white dwarf, with the
maximum of the FUV and UV continuum and broad emission line flux light curves
coincident with maximum blueshift of the broad O VI emission component. On the
binary phase, the broad dip in the EUV light curve is accompanied by strong
eclipses of the UV emission lines and by variations in both the flux and radial
velocity of the O VI narrow emission component. The available data are
consistent with the accretion funnel being the source of the FUV and UV
continuum and the O VI broad emission component, and the white dwarf being the
source of the O VI narrow emission component.Comment: 21 pages, 10 Postscript figures; LaTeX format, uses aaspp4.sty;
table2.tex included separately because it must be printed sideways - see
instructions in the file; accepted on 1999 Feb 20 for publication in The
Astrophysical Journa
Inferior frontal gyrus activation predicts individual differences in perceptual learning of cochlear-implant simulations
This study investigated the neural plasticity associated with perceptual learning of a cochlear implant (CI) simulation. Normal-hearing listeners were trained with vocoded and spectrally-shifted speech simulating a CI while cortical responses were measured with fMRI. A condition in which the vocoded speech was spectrally inverted provided a control for learnability and adaptation. Behavioral measures showed considerable individual variability both in the ability to learn to understand the degraded speech, and in phonological working memory capacity. Neurally, left-lateralized regions in superior temporal sulcus and inferior frontal gyrus (IFG) were sensitive to the learnability of the simulations, but only the activity in prefrontal cortex correlated with inter-individual variation in intelligibility scores and phonological working memory. A region in left angular gyrus (AG) showed an activation pattern that reflected learning over the course of the experiment, and co-variation of activity in AG and IFG was modulated by the learnability of the stimuli. These results suggest that variation in listeners' ability to adjust to vocoded and spectrally-shifted speech is partly reflected in differences in the recruitment of higher-level language processes in prefrontal cortex, and that this variability may further depend on functional links between the left inferior frontal gyrus and angular gyrus. Differences in the engagement of left inferior prefrontal cortex, and its co-variation with posterior parietal areas, may thus underlie some of the variation in speech perception skills that have been observed in clinical populations of CI users
Effect of Stannous Fluoride and Iodine on Root Caries and Bone Loss in Rats
Author Institution: The Ohio State University, College of DentistryRice rats were distributed by littermate into four experimental groups as follows: stannous fluoride (0.4%), iodine-sodium iodide (1.0%), a combination of iodine-sodium iodide and stannous fluoride, and a distilled water control. Each rat was treated by swabbing the molar teeth daily. All rats were fed diet 2000 and double-distilled water ad libitum, and were sacrificed after 9 weeks. Root surface caries and bone loss were determined. Root surface caries was significantly (P < 0.05) inhibited by stannous fluoride and the combination of iodine-sodium iodide and stannous fluoride, but was not affected significantly by iodinesodium iodide alone. On the other hand, bone loss scores were significantly lower in all groups compared to the demineralized water control
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