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Seven-year climatology of dust opacity on Mars
This paper describes the procedure we have used to produce multi-annual dust scenarios for Martian years 24 to 30 from a multi-instrument dataset of total dust opacity observations. This procedure includes gridding the observations on a pre-defined longitude-latitude grid with 1 sol resolution in time, and spatially interpolating the results to obtain complete daily maps of total dust opacity. We used weighted binning as gridding technique, and spatial kriging as method of interpolation. The new dust scenarios are available as NetCDF files, easy to interface to any model including global circulation and mesoscale models for the Martian atmosphere
Evolving social behavior through selection of single-cell adhesion in Dictyostelium discoideum
The social amoeba Dictyostelium discoideum commonly forms chimeric fruiting bodies. Genetic variants that produce a higher proportion of spores are predicted to undercut multicellular organization unless cooperators assort positively. Cell adhesion is considered a primary factor driving such assortment, but evolution of adhesion has not been experimentally connected to changes in social performance. We modified by experimental evolution the efficiency of individual cells in attaching to a surface. Surprisingly, evolution appears to have produced social cooperators irrespective of whether stronger or weaker adhesion was selected. Quantification of reproductive success, cell-cell adhesion, and developmental patterns, however, revealed two distinct social behaviors, as captured when the classical metric for social success is generalized by considering clonal spore production. Our work shows that cell mechanical interactions can constrain the evolution of development and sociality in chimeras and that elucidation of proximate mechanisms is necessary to understand the ultimate emergence of multicellular organization
Highly efficient multilayer organic pure-blue-light emitting diodes with substituted carbazoles compounds in the emitting layer
Bright blue organic light-emitting diodes (OLEDs) based on
1,4,5,8,N-pentamethylcarbazole (PMC) and on dimer of N-ethylcarbazole
(N,N'-diethyl-3,3'-bicarbazyl) (DEC) as emitting layers or as dopants in a
4,4'-bis(2,2'-diphenylvinyl)-1,1'-biphenyl (DPVBi) matrix are described. Pure
blue-light with the C.I.E. coordinates x = 0.153 y = 0.100, electroluminescence
efficiency \eta_{EL} of 0.4 cd/A, external quantum efficiency \eta_{ext.} of
0.6% and luminance L of 236 cd/m2 (at 60 mA/cm2) were obtained with PMC as an
emitter and the 2,9-dimethyl-4,7-diphenyl-1,10-phenantroline (BCP) as a
hole-blocking material in five-layer emitting devices. The highest efficiencies
\eta_{EL.} of 4.7 cd/A, and \eta_{ext} = 3.3% were obtained with a four-layer
structure and a DPVBi DEC-doped active layer (CIE coordinates x = 0.158,
y=0.169, \lambda_{peak} = 456 nm). The \eta_{ext.} value is one the highest
reported at this wavelength for blue OLEDs and is related to an internal
quantum efficiency up to 20%
Unconventional high-energy-state contribution to the Cooper pairing in under-doped copper-oxide superconductor HgBaCaCuO
We study the temperature-dependent electronic B1g Raman response of a
slightly under-doped single crystal HgBaCaCuO with a
superconducting critical temperature Tc=122 K. Our main finding is that the
superconducting pair-breaking peak is associated with a dip on its
higher-energy side, disappearing together at Tc. This result hints at an
unconventional pairing mechanism, whereas spectral weight lost in the dip is
transferred to the pair-breaking peak at lower energies. This conclusion is
supported by cellular dynamical mean-field theory on the Hubbard model, which
is able to reproduce all the main features of the B1g Raman response and
explain the peak-dip behavior in terms of a nontrivial relationship between the
superconducting and the pseudo gaps.Comment: 7 pages 4 figure
Spin Dynamics in Cuprates: Optical Conductivity of HgBa2CuO4
The electron-boson spectral density function I^2ChiOmega responsible for
carrier scattering of the high temperature superconductor HgBa2CuO4 (Tc = 90 K)
is calculated from new data on the optical scattering rate. A maximum entropy
technique is used. Published data on HgBa2Ca2Cu3O8 (Tc = 130 K) are also
inverted and these new results are put in the context of other known cases. All
spectra (with two notable exceptions) show a peak at an energy (Omega_r)
proportional to the superconducting transition temperature Omega_r ~= 6.3
kB.Tc. This charge channel relationship follows closely the magnetic resonance
seen by polarized neutron scattering, Omega_r^{neutron} ~= 5.4 kB.Tc. The
amplitudes of both peaks decrease strongly with increasing temperature. In some
cases, the peak at Omega_r is weak and the spectrum can have additional maxima
and a background extending up to several hundred meV
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