229 research outputs found
Oxygen surface exchange and diffusion in fast ionic conductors
The rate of oxygen surface exchange on selected bulk oxides exhibiting enhanced oxygen ion conductivity has been derived by measuring 18O penetration profiles using a high sensitivity dynamic SIMS technique. These values for the oxygen surface exchange coefficient (K) were used to derive the steady-state oxygen fluxes through the oxide surface for conditions when the bulk oxide was in equilibrium with 1 atm. of oxygen at 500 and 700°C. The oxygen fluxes were transformed into current fluxes and compared with available exchange current densities (iO) measured using electrochemical techniques. The two sets of current densities exhibited large differences for zirconia based electrolytes which confirmed the important role of platinum as an electro-catalyst. However for bismuth based electrolytes good agreement was noted between the two sets of iO values. It was concluded therefore that the dissociative adsorption of oxygen occurred predominately on the surface of the Bi2O3 based electrolyte and that the presence of a metal electrode (Pt or Au) had little effect upon the overall exchange current kinetics
Sleep-Disordered Breathing Affects Auditory Processing in 5â7 Year-Old Children: Evidence From Brain Recordings
Poor sleep in children is associated with lower neurocognitive functioning and increased maladaptive behaviors. The current study examined the impact of snoring (the most common manifestation of sleep-disordered breathing) on cognitive and brain functioning in a sample of 35 asymptomatic children ages 5â7 years identified in the community as having habitual snoring (SDB). All participants completed polysomnographic, neurocognitive (NEPSY) and psychophysiological (ERPs to speech sounds) assessments. The results indicated that sub-clinical levels of SDB may not necessarily lead to reduced performance on standardized behavioral measures of attention and memory. However, brain indices of speech perception and discrimination (N1/P2) are sensitive to individual differences in the quality of sleep. We postulate that addition of ERPs to the standard clinical measures of sleep problems could lead to early identification of children who may be more cognitively vulnerable because of chronic sleep disturbances
Smoking during Pregnancy Affects Speech-Processing Ability in Newborn Infants
BACKGROUND: Tobacco smoking during pregnancy is known to adversely affect development of the central nervous system in babies of smoking mothers by restricting uteroâplacental blood flow and the amount of oxygen available to the fetus. Behavioral data associate maternal smoking with lower verbal scores and poorer performance on specific language/auditory tests.
OBJECTIVES: In the current study we examined the effects of maternal smoking during pregnancy on newbornsâ speech processing ability as measured by event-related potentials (ERPs).
METHOD: High-density ERPs were recorded within 48 hr of birth in healthy newborn infants of smoking (n = 8) and nonsmoking (n = 8) mothers. Participating infants were matched on sex, gestational age, birth weight, Apgar scores, motherâs education, and family income. Smoking during pregnancy was determined by parental self-report and medical records. ERPs were recorded in response to six consonantâvowel syllables presented in random order with equal probability.
RESULTS: Brainwaves of babies of nonsmoking mothers were characterized by typical hemisphere asymmetries, with larger amplitudes over the left hemisphere, especially over temporal regions. Further, infants of nonsmokers discriminated among a greater number of syllables whereas the newborns of smokers began the discrimination process at least 150 msec later and differentiated among fewer stimuli.
CONCLUSIONS: Our findings indicate that prenatal exposure to tobacco smoke in otherwise healthy babies is linked with significant changes in brain physiology associated with basic perceptual skills that could place the infant at risk for later developmental problems
Smoking during Pregnancy Affects Speech-Processing Ability in Newborn Infants
BACKGROUND: Tobacco smoking during pregnancy is known to adversely affect development of the central nervous system in babies of smoking mothers by restricting uteroâplacental blood flow and the amount of oxygen available to the fetus. Behavioral data associate maternal smoking with lower verbal scores and poorer performance on specific language/auditory tests.
OBJECTIVES: In the current study we examined the effects of maternal smoking during pregnancy on newbornsâ speech processing ability as measured by event-related potentials (ERPs).
METHOD: High-density ERPs were recorded within 48 hr of birth in healthy newborn infants of smoking (n = 8) and nonsmoking (n = 8) mothers. Participating infants were matched on sex, gestational age, birth weight, Apgar scores, motherâs education, and family income. Smoking during pregnancy was determined by parental self-report and medical records. ERPs were recorded in response to six consonantâvowel syllables presented in random order with equal probability.
RESULTS: Brainwaves of babies of nonsmoking mothers were characterized by typical hemisphere asymmetries, with larger amplitudes over the left hemisphere, especially over temporal regions. Further, infants of nonsmokers discriminated among a greater number of syllables whereas the newborns of smokers began the discrimination process at least 150 msec later and differentiated among fewer stimuli.
CONCLUSIONS: Our findings indicate that prenatal exposure to tobacco smoke in otherwise healthy babies is linked with significant changes in brain physiology associated with basic perceptual skills that could place the infant at risk for later developmental problems
Abundance and evolution of galaxy clusters in cosmological models with massive neutrino
The time evolution of the number density of galaxy clusters and their mass
and temperature functions are used to constrain cosmological parameters in the
spatially flat dark matter models containing a fraction of hot particles
(massive neutrino) additional to cold and baryonic matter. We test the modified
MDM models with cosmic gravitational waves and show that they neither pass the
cluster evolution test nor reproduce the observed height of the first acoustic
peak in spectrum, and therefore should be ruled out. The models
with a non-zero cosmological constant are in better agreement with
observations. We estimate the free cosmological parameters in MDM with
a negligible abundance of gravitational waves, and find that within the
parameter ranges , , (i) the value of
is strongly affected by a small fraction of hot dark matter,
:
( CL), and (ii) the redshift evolution of galaxy clusters alone
reveals the following explicit correlation between and
: . The present accuracy of
observational data allows only to bound the fraction of hot matter, (the number of massive neutrino species remains undelimited, ).Comment: 9 pages, 7 figures, submitted in A&
A One-Hour Sleep Restriction Impacts Brain Processing in Young Children Across Tasks: Evidence From Event-related Potentials
The effect of mild sleep restriction on cognitive functioning in young children is unclear, yet sleep loss may impact children\u27s abilities to attend to tasks with high processing demands. In a preliminary investigation, six children (6.6 - 8.3 years of age) with normal sleep patterns performed three tasks: attention (âOddballâ), speech perception (conconant-vowel syllables) and executive function (Directional Stroop). Event-related potentials (ERP) responses were recorded before (Control) and following one-week of 1-hour per day of sleep restriction. Brain activity across all tasks following Sleep Restriction differed from activity during Control Sleep, indicating that minor sleep restriction impacts children\u27s neurocognitive functioning
Smoking during Pregnancy Affects Speech-Processing Ability in Newborn Infants
BACKGROUND: Tobacco smoking during pregnancy is known to adversely affect development of the central nervous system in babies of smoking mothers by restricting uteroâplacental blood flow and the amount of oxygen available to the fetus. Behavioral data associate maternal smoking with lower verbal scores and poorer performance on specific language/auditory tests. OBJECTIVES: In the current study we examined the effects of maternal smoking during pregnancy on newbornsâ speech processing ability as measured by event-related potentials (ERPs). METHOD: High-density ERPs were recorded within 48 hr of birth in healthy newborn infants of smoking (n = 8) and nonsmoking (n = 8) mothers. Participating infants were matched on sex, gestational age, birth weight, Apgar scores, motherâs education, and family income. Smoking during pregnancy was determined by parental self-report and medical records. ERPs were recorded in response to six consonantâvowel syllables presented in random order with equal probability. RESULTS: Brainwaves of babies of nonsmoking mothers were characterized by typical hemisphere asymmetries, with larger amplitudes over the left hemisphere, especially over temporal regions. Further, infants of nonsmokers discriminated among a greater number of syllables whereas the newborns of smokers began the discrimination process at least 150 msec later and differentiated among fewer stimuli. CONCLUSIONS: Our findings indicate that prenatal exposure to tobacco smoke in otherwise healthy babies is linked with significant changes in brain physiology associated with basic perceptual skills that could place the infant at risk for later developmental problems
Measurement of and charged current inclusive cross sections and their ratio with the T2K off-axis near detector
We report a measurement of cross section and the first measurements of the cross section
and their ratio
at (anti-)neutrino energies below 1.5
GeV. We determine the single momentum bin cross section measurements, averaged
over the T2K -flux, for the detector target material (mainly
Carbon, Oxygen, Hydrogen and Copper) with phase space restricted laboratory
frame kinematics of 500 MeV/c. The
results are and $\sigma(\nu)=\left( 2.41\
\pm0.022{\rm{(stat.)}}\pm0.231{\rm (syst.)}\ \right)\times10^{-39}^{2}R\left(\frac{\sigma(\bar{\nu})}{\sigma(\nu)}\right)=
0.373\pm0.012{\rm (stat.)}\pm0.015{\rm (syst.)}$.Comment: 18 pages, 8 figure
Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS
The chi_b(nP) quarkonium states are produced in proton-proton collisions at
the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS
detector. Using a data sample corresponding to an integrated luminosity of 4.4
fb^-1, these states are reconstructed through their radiative decays to
Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks
corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new
structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is
also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes.
This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table,
corrected author list, matches final version in Physical Review Letter
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