776 research outputs found
A Justification for Semantic Training in Data Curation Frameworks Development
In the complex data curation activities involving proper data access, data use optimization and data rescue, opportunities exist where underlying skills in semantics may play a crucial role in data curation professionals ranging from data scientists, to informaticists, to librarians. Here, We provide a conceptualization of semantics use in the education data curation framework (EDCF) (Fig. 1) [1] under development by Purdue University and endorsed by the GLOBE program [2] for further development and application. Our work shows that a comprehensive data science training includes both spatial and non-spatial data, where both categories are promoted by standard efforts of organizations such as the Open Geospatial Consortium (OGC) and the World Wide Web Consortium (W3C), as well as organizations such as the Federation of Earth Science Information Partners (ESIP) that share knowledge and propagate best practices in applications
Superconducting gap of overdoped Tl2Ba2CuO6+d observed by Raman scattering
We report Raman scattering spectra for single crystals of overdoped
Tl2Ba2CuO6+d (Tl-2201) at low temperatures. It was observed that the
pair-breaking peaks in A1g and B1g spectra radically shift to lower energy with
carrier doping. We interpret it as s-wave component mixing into d-wave,
although the crystal structure is tetragonal. Since similar phenomena were
observed also in YBa2Cu3Oy and Bi2Sr2CaCu2Oz, we conclude that s-wave mixing is
a common property for overdoped high-Tc superconductors.Comment: 8 pages, 3 figures, proceedings of SNS200
Young neutron stars with soft gamma ray emission and anomalous X-ray pulsar
The observational properties of Soft Gamma Repeaters and Ano\-malous X-ray
Pulsars (SGR/AXP) indicate to necessity of the energy source different from a
rotational energy of a neutron star. The model, where the source of the energy
is connected with a magnetic field dissipation in a highly magnetized neutron
star (magnetar) is analyzed. Some observational inconsistencies are indicated
for this interpretation. The alternative energy source, connected with the
nuclear energy of superheavy nuclei stored in the nonequilibrium layer of low
mass neutron star is discussed.Comment: 29 pages, 13 figures, Springer International Publishing Switzerland
2016 A.W. Alsabti, P. Murdin (eds.), Handbook of Supernova
Orthorhombicity mixing of s- and d- gap components in without involving the chains
Momentum decoupling develops when forward scattering dominates the pairing
interaction and implies tendency for decorrelation between the physical
behavior in the various regions of the Fermi surface. In this regime it is
possible to obtain anisotropic s- or d-wave superconductivity even with
isotropic pairing scattering. We show that in the momentum decoupling regime
the distortion of the planes is enough to explain the experimental
reports for s- mixing in the dominantly d-wave gap of . In the
case of spin fluctuations mediated pairing instead, a large part of the
condensate must be located in the chains in order to understand the
experiments.Comment: LATEX file and 3 Postscript figure
The Influence of Free Quintessence on Gravitational Frequency Shift and Deflection of Light with 4D momentum
Based on the 4D momentum, the influence of quintessence on the gravitational
frequency shift and the deflection of light are examined in modified
Schwarzschild space. We find that the frequency of photon depends on the state
parameter of quintessence : the frequency increases for and
decreases for . Meanwhile, we adopt an integral power number
() to solve the orbital equation of photon. The photon's
potentials become higher with the decrease of . The behavior of
bending light depends on the state parameter sensitively. In
particular, for the case of , there is no influence on the
deflection of light by quintessence. Else, according to the H-masers of GP-A
redshift experiment and the long-baseline interferometry, the constraints on
the quintessence field in Solar system are presented here.Comment: 12 pages, 2 figures, 4 tables. European Physical Journal C in pres
Coevolved mutations reveal distinct architectures for two core proteins in the bacterial flagellar motor
Switching of bacterial flagellar rotation is caused by large domain movements of the FliG protein triggered by binding of the signal protein CheY to FliM. FliG and FliM form adjacent multi-subunit arrays within the basal body C-ring. The movements alter the interaction of the FliG C-terminal (FliGC) "torque" helix with the stator complexes. Atomic models based on the Salmonella entrovar C-ring electron microscopy reconstruction have implications for switching, but lack consensus on the relative locations of the FliG armadillo (ARM) domains (amino-terminal (FliGN), middle (FliGM) and FliGC) as well as changes during chemotaxis. The generality of the Salmonella model is challenged by the variation in motor morphology and response between species. We studied coevolved residue mutations to determine the unifying elements of switch architecture. Residue interactions, measured by their coevolution, were formalized as a network, guided by structural data. Our measurements reveal a common design with dedicated switch and motor modules. The FliM middle domain (FliMM) has extensive connectivity most simply explained by conserved intra and inter-subunit contacts. In contrast, FliG has patchy, complex architecture. Conserved structural motifs form interacting nodes in the coevolution network that wire FliMM to the FliGC C-terminal, four-helix motor module (C3-6). FliG C3-6 coevolution is organized around the torque helix, differently from other ARM domains. The nodes form separated, surface-proximal patches that are targeted by deleterious mutations as in other allosteric systems. The dominant node is formed by the EHPQ motif at the FliMMFliGM contact interface and adjacent helix residues at a central location within FliGM. The node interacts with nodes in the N-terminal FliGc α-helix triad (ARM-C) and FliGN. ARM-C, separated from C3-6 by the MFVF motif, has poor intra-network connectivity consistent with its variable orientation revealed by structural data. ARM-C could be the convertor element that provides mechanistic and species diversity.JK was supported by Medical Research Council grant U117581331. SK was supported by seed funds from Lahore University of Managment Sciences (LUMS) and the Molecular Biology Consortium
Constraining the Power Spectrum using Clusters
(Shortened Abstract). We analyze a redshift sample of Abell/ACO clusters and
compare them with numerical simulations based on the truncated Zel'dovich
approximation (TZA), for a list of eleven dark matter (DM) models. For each
model we run several realizations, on which we estimate cosmic variance
effects. We analyse correlation statistics, the probability density function,
and supercluster properties from percolation analysis. As a general result, we
find that the distribution of galaxy clusters provides a constraint only on the
shape of the power spectrum, but not on its amplitude: a shape parameter 0.18 <
\Gamma < 0.25 and an effective spectral index at 20Mpc/h in the range
[-1.1,-0.9] are required by the Abell/ACO data. In order to obtain
complementary constraints on the spectrum amplitude, we consider the cluster
abundance as estimated using the Press--Schechter approach, whose reliability
is explicitly tested against N--body simulations. We conclude that, of the
cosmological models considered here, the only viable models are either Cold+Hot
DM ones with \Omega_\nu = [0.2-0.3], better if shared between two massive
neutrinos, and flat low-density CDM models with \Omega_0 = [0.3-0.5].Comment: 37 pages, Latex file, 9 figures; New Astronomy, in pres
Growth Kinetics in Layer‐by‐Layer Assemblies of Organic Nanoparticles and Polyelectrolytes
The growth rates of layer‐by‐layer (LbL) assemblies of polyelectrolytes (PEs) with oppositely charged polystyrene (PS) nanoparticles (NPs) as a function of molecular weight (MW) of the PEs, ionic strength of the media, and NP size and charge are systematically investigated. To optimize LbL growth, the effects of suspension concentration, pH of the media, and deposition time on the growth rate of multilayers are assessed. Both linear and exponential growth behaviors are observed and, under optimal conditions, films of up to around 1 μm thick can readily be assembled after 10 or so bilayers have been deposited. For many of the cases studied, an intermediate MW of PE leads to the fastest film buildup, for both cationic poly(ethyleneimine) deposited alternately with anionic PS NPs and for anionic poly(acrylic acid) deposited alternately with cationic PS NPs. The existence of an optimal MW suggests that growth rate is determined by a balance of thermodynamic factors, including density of polymer bridges between particles, and kinetic factors, specifically the diffusivity of polymer in the film. The optimal MW, however, is very sensitive to the materials used. Moreover, depending on the MW of the PE, increasing salinity could increase or decrease the growth kinetics. Finally, the surface morphology of the films is characterized with AFM and SEM to reveal that the roughness increases less than linearly with film thickness.Growth factors: The growth rates of layer‐by‐layer (LbL) assemblies of polyelectrolytes (PEs) with oppositely charged polystyrene nanoparticles are systematically investigated. The molecular weight of a PE has a considerable effect on LbL film growth and its surface morphology (see figure).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135666/1/cphc201600789_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135666/2/cphc201600789-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135666/3/cphc201600789.pd
Hypernovae and Other Black-Hole-Forming Supernovae
During the last few years, a number of exceptional core-collapse supernovae
(SNe) have been discovered. Their kinetic energy of the explosions are larger
by more than an order of magnitude than the typical values for this type of
SNe, so that these SNe have been called `Hypernovae'. We first describe how the
basic properties of hypernovae can be derived from observations and modeling.
These hypernovae seem to come from rather massive stars, thus forming black
holes. On the other hand, there are some examples of massive SNe with only a
small kinetic energy. We suggest that stars with non-rotating black holes are
likely to collapse "quietly" ejecting a small amount of heavy elements (Faint
supernovae). In contrast, stars with rotating black holes are likely to give
rise to very energetic supernovae (Hypernovae). We present distinct
nucleosynthesis features of these two types of "black-hole-forming" supernovae.
Hypernova nucleosynthesis is characterized by larger abundance ratios
(Zn,Co,V,Ti)/Fe and smaller (Mn,Cr)/Fe. Nucleosynthesis in Faint supernovae is
characterized by a large amount of fall-back. We show that the abundance
pattern of the most Fe deficient star, HE0107-5240, and other extremely
metal-poor carbon-rich stars are in good accord with those of
black-hole-forming supernovae, but not pair-instability supernovae. This
suggests that black-hole-forming supernovae made important contributions to the
early Galactic (and cosmic) chemical evolution.Comment: 49 pages, to be published in "Stellar Collapse" (Astrophysics and
Space Science; Kluwer) ed. C. L. Fryer (2003
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