5,023 research outputs found
Neutron inelastic scattering investigation of the magnetic excitations in Cu_2Te_2O_5X_2 (X=Br, Cl)
Neutron inelastic scattering investigations have been performed on the spin
tetrahedral system Cu_2Te_2O_5X_2 (X = Cl, Br). We report the observation of
magnetic excitations with a dispersive component in both compounds, associated
with the 3D incommensurate magnetic order that develops below =18.2
K and =11.4 K. The excitation in Cu_2Te_2O_5Cl_2 softens as the
temperature approaches , leaving diffuse quasi-elastic scattering
above the transition temperature. In the bromide, the excitations are present
well above , which might be attributed to the presence of a degree
of low dimensional correlations above in this compound
Raman excitation spectroscopy of carbon nanotubes: effects of pressure medium and pressure
Raman excitation and emission spectra for the radial breathing mode (RBM) are
reported, together with a preliminary analysis. From the position of the peaks
on the two-dimensional plot of excitation resonance energy against Raman shift,
the chiral indices (m, n) for each peak are identified. Peaks shift from their
positions in air when different pressure media are added - water, hexane,
sulphuric acid - and when the nanotubes are unbundled in water with surfactant
and sonication. The shift is about 2 - 3 cm-1 in RBM frequency, but
unexpectedly large in resonance energy, being spread over up to 100meV for a
given peak. This contrasts with the effect of pressure. The shift of the peaks
of semiconducting nanotubes in water under pressure is orthogonal to the shift
from air to water. This permits the separation of the effects of the pressure
medium and the pressure, and will enable the true pressure coefficients of the
RBM and the other Raman peaks for each (m, n) to be established unambiguously.Comment: 6 pages, 3 Figures, Proceedings of EHPRG 2011 (Paris
Forehead reflectance photoplethysmography to monitor heart rate: preliminary results from neonatal patients
Around 5%–10% of newborn babies require some form of resuscitation at birth and heart rate (HR) is the best guide of efficacy. We report the development and first trial of a device that continuously monitors neonatal HR, with a view to deployment in the delivery room to guide newborn resuscitation. The device uses forehead reflectance photoplethysmography (PPG) with modulated light and lock-in detection. Forehead fixation has numerous advantages including ease of sensor placement, whilst perfusion at the forehead is better maintained in comparison to the extremities. Green light (525 nm) was used, in preference to the more usual red or infrared wavelengths, to optimize the amplitude of the pulsatile signal. Experimental results are presented showing simultaneous PPG and electrocardiogram (ECG) HRs from babies (n = 77), gestational age 26–42 weeks, on a neonatal intensive care unit. In babies ≥32 weeks gestation, the median reliability was 97.7% at ±10 bpm and the limits of agreement (LOA) between PPG and ECG were +8.39 bpm and −8.39 bpm. In babies <32 weeks gestation, the median reliability was 94.8% at ±10 bpm and the LOA were +11.53 bpm and −12.01 bpm. Clinical evaluation during newborn deliveries is now underway
Inferencing Abilities of Deaf College Students: Foundations and Implications for Metaphor Comprehension and Theory of Mind
Understanding nonliteral language requires inferencing ability and is an important but complex aspect of social interaction, involving cognitive (e.g., theory of mind, executive function) as well as language skill, areas in which many deaf individuals struggle. This study examined comprehension of metaphor and sarcasm, assessing the contributions of hearing status, inferencing ability, executive function (verbal short-term/working memory capacity), and deaf individuals’ communication skills (spoken versus signed language, cochlear implant use). Deaf and hearing college students completed a multiple-choice metaphor comprehension task and inferencing tasks that included both social-emotional (i.e., theory of mind) and neutral inferences, as well as short-term memory span and working memory tasks. Results indicated the hearing students to have better comprehension of nonliteral language and the ability to make social-emotional inferences, as well as greater memory capacity. Deaf students evidenced strong relationships among inferential comprehension, communication skills, and memory capacity, with substantial proportions of the variance in understanding of metaphor and sarcasm accounted for by these variables. The results of this study enhance understanding of the language and cognitive skills underlying figurative language comprehension and theory of mind and have implications for the social functioning of deaf individuals
Electron-impact ionization of atomic hydrogen at 2 eV above threshold
The convergent close-coupling method is applied to the calculation of fully
differential cross sections for ionization of atomic hydrogen by 15.6 eV
electrons. We find that even at this low energy the method is able to yield
predictive results with small uncertainty. As a consequence we suspect that the
experimental normalization at this energy is approximately a factor of two too
high.Comment: 10 page
A Genome-Wide Association Study for Calving Interval in Holstein Dairy Cows Using Weighted Single-Step Genomic BLUP Approach.
The aim of the present study was to identify genomic region(s) associated with the length of the calving interval in primiparous (n = 6866) and multiparous (n = 5071) Holstein cows. The single nucleotide polymorphism (SNP) solutions were estimated using a weighted single-step genomic best linear unbiased prediction (WssGBLUP) approach and imputed high-density panel (777 k) genotypes. The effects of markers and the genomic estimated breeding values (GEBV) of the animals were obtained by five iterations of WssGBLUP. The results showed that the accuracies of GEBVs with WssGBLUP improved by +5.4 to +5.7, (primiparous cows) and +9.4 to +9.7 (multiparous cows) percent points over accuracies from the pedigree-based BLUP. The most accurate genomic evaluation was provided at the second iteration of WssGBLUP, which was used to identify associated genomic regions using a windows-based GWAS procedure. The proportion of additive genetic variance explained by windows of 50 consecutive SNPs (with an average of 165 Kb) was calculated and the region(s) that accounted for equal to or more than 0.20% of the total additive genetic variance were used to search for candidate genes. Three windows of 50 consecutive SNPs (BTA3, BTA6, and BTA7) were identified to be associated with the length of the calving interval in primi- and multiparous cows, while the window with the highest percentage of explained genetic variance was located on BTA3 position 49.42 to 49.52 Mb. There were five genes including , , , , and inside the windows associated with the length of the calving interval. The biological process terms including alanine transport, L-alanine transport, proline transport, and glycine transport were identified as the most important terms enriched by the genes inside the identified windows
Pressure coefficients of Raman modes of carbon nanotubes resolved by chirality: Environmental effect on graphene sheet
Studies of the mechanical properties of single-walled carbon nanotubes are
hindered by the availability only of ensembles of tubes with a range of
diameters. Tunable Raman excitation spectroscopy picks out identifiable tubes.
Under high pressure, the radial breathing mode shows a strong environmental
effect shown here to be largely independent of the nature of the environment .
For the G-mode, the pressure coefficient varies with diameter consistent with
the thick-wall tube model. However, results show an unexpectedly strong
environmental effect on the pressure coefficients. Reappraisal of data for
graphene and graphite gives the G-mode Grueuneisen parameter gamma = 1.34 and
the shear deformation parameter beta = 1.34.Comment: Submitted to Physical Review
Deep Space Network information system architecture study
The purpose of this article is to describe an architecture for the Deep Space Network (DSN) information system in the years 2000-2010 and to provide guidelines for its evolution during the 1990s. The study scope is defined to be from the front-end areas at the antennas to the end users (spacecraft teams, principal investigators, archival storage systems, and non-NASA partners). The architectural vision provides guidance for major DSN implementation efforts during the next decade. A strong motivation for the study is an expected dramatic improvement in information-systems technologies, such as the following: computer processing, automation technology (including knowledge-based systems), networking and data transport, software and hardware engineering, and human-interface technology. The proposed Ground Information System has the following major features: unified architecture from the front-end area to the end user; open-systems standards to achieve interoperability; DSN production of level 0 data; delivery of level 0 data from the Deep Space Communications Complex, if desired; dedicated telemetry processors for each receiver; security against unauthorized access and errors; and highly automated monitor and control
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