27,769 research outputs found
A strong electroweak phase transition in the 2HDM after LHC8
The nature of the electroweak phase transition in two-Higgs-doublet models is revisited in light of the recent LHC results. A scan over an extensive region of their parameter space is performed, showing that a strongly first-order phase transition favours a light neutral scalar with SM-like properties, together with a heavy pseudo-scalar (m_A^0 > 400 GeV) and a mass hierarchy in the scalar sector, m_H^+ gamma gamma decay channel and find that an enhancement in the branching ratio is allowed, and in some cases even preferred, when a strongly first-order phase transition is required
Discovery of the secondary eclipse of HAT-P-11 b
We report the detection of the secondary eclipse of HAT-P-11 b, a
Neptune-sized planet orbiting an active K4 dwarf. Using all available
short-cadence data of the Kepler mission, we derive refined planetary ephemeris
increasing their precision by more than an order of magnitude. Our simultaneous
primary and secondary transit modeling results in improved transit and orbital
parameters. In particular, the precise timing of the secondary eclipse allows
to pin down the orbital eccentricity to . The
secondary eclipse depth of ppm corresponds to a
detection and results in a geometric albedo of for
HAT-P-11 b, close to Neptune's value, which may indicate further resemblances
between these two bodies. Due to the substantial orbital eccentricity, the
planetary equilibrium temperature is expected to change significantly with
orbital position and ought to vary between K and K,
depending on the details of heat redistribution in the atmosphere of HAT-P-11
b.Comment: Accepted by A&A, 27/10/201
Spin dynamics in a superconductor / ferromagnet proximity system
The ferromagnetic resonance of thin sputtered Ni80Fe20 films grown on Nb is
measured. By varying the temperature and thickness of the Nb the role of the
superconductivity on the whole ferromagnetic layer in these heterostructures is
explored. The change in the spin transport properties below the superconducting
transition of the Nb is found to manifest itself in the Ni80Fe20 layer by a
sharpening in the resonance of the ferromagnet, or a decrease in the effective
Gilbert damping co-efficient. This dynamic proximity effect is in contrast to
low frequency studies in these systems, where the effect of the superconductor
is confined to a small region in the ferromagnet. We interpret this in terms of
the spin pumping model.Comment: 4 pages, 4 figures, to be submitted for publicatio
Ontogeny of purinergic receptor-regulated Ca2+ signaling in mouse cortical collecting duct epithelium
Changes in ATP-induced increase in {[}Ca2+], during collecting duct ontogeny were studied in primary monolayer cultures of mouse ureteric bud (UB) and cortical collecting duct (CCD) cells by Fura-PE3 fluorescence ratio imaging. In UB (embryonic day E14 and postnatal day P1) the ATIP-stimulated increase (EC50 approximate to 1 muM) in fluorescence ratio (DeltaR(ATP)) was independent of extracellular Ca2+ and insensitive to the P2 purinoceptor-antagonist suramin (1 mM). From day P7 onward when CCD morphogenesis had been completed DeltaR(ATP) increased and became dependent on extracellular Ca2+. This ATP-stimulated Ca2+ entry into CCD cells was non-capacitative and suramin (11 mM)insensitive, but sensitive to nifedipine (30 muM) and enhanced by Bay K8644 (15 muM), a blocker and an agonist of L-type Ca2+ channels, respectively. Quantitative RT-PCR demonstrated similar mRNA expression of L-type Ca2+ channel alpha1-subunit, P2Y(1), P2Y(2), and P2X(4b) purinoceptors in UB and CCD monolayers while the abundance of P2X(4) mRNA increased with CCD morphogenesis. In conclusion, both embryonic and postnatal cells express probably P2Y(2)-stimulated Ca2+ release from intracellular stores. With development, the CCD epithelium acquires ATP-stimulated Ca2+ entry via L-type Ca2+ channels. This pathway might by mediated by the increasing expression of P2X(4)-receptors resulting in an increasing ATP-dependent membrane depolarization and activation of L-type Ca2+ channels. Copyright (C) 2002 S. Karger AG, Basel
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