3,773 research outputs found
Multiproxy geochemical analysis of a Panthalassic margin record of the early Toarcian oceanic anoxic event (Toyora area, Japan)
Peer reviewedPublisher PD
Sedimentary evidence for enhanced hydrological cycling in response to rapid carbon release during the early Toarcian oceanic anoxic event
Part of this work was financially supported by JSPS KAKENHI 12J08818 and 15J08821 to KI. DBK acknowledges recipe of NERC Fellowship NE/I02089X/1 and grants from the Sasakawa Foundation of Great Britain, grant number 4883, and Daiwa Anglo-Japanese Foundation, grant number 10960/12369. This study contributes to IGCP 655. We thank M. Ikeda, T. Ohta, K. Suzuki, N. Nishida and K. Kawano for assistance in the field and/or helpful discussion. Fieldwork was carried out with full permission and support from its landowners. S. Nicoara and S. Kurokawa are thanked for analytical assistance. The comments of the Editor (D. Vance) and three reviewers (G. Suan, S. Bodin, and an anonymous reviewer) greatly improved the manuscript.Peer reviewedPostprin
Oceanic redox conditions through the late Pliensbachian to early Toarcian on the northwestern Panthalassa margin : Insights from pyrite and geochemical data
Part of this work was financially supported by JSPS grants 15J08821 to KI. DBK acknowledges receipt of NERC Fellowship NE/I02089X/1, and grants from the Great Britain Sasakawa Foundation: grant number 4883 and Daiwa Anglo-Japanese Foundation: grant number 10960/12369. This study contributes to IGCP 655. We thank M. Ikeda, T. Ohta, K. Suzuki, S. Itamiya, and K. Kawano for assistance in the field and/or helpful discussion. Fieldwork was carried out with full permission and support from its landowners. Technical staff at Geo-Science Laboratory (Chikyu Kagaku Kenkyusho) are thanked for performance of TOC and carbon-isotope analysis.Peer reviewedPostprin
Helium Nova on a Very Massive White Dwarf -- A Light Curve Model of V445 Puppis (2000) Revised
V445 Pup (2000) is a unique object identified as a helium nova. Color indexes
during the outburst are consistent with those of free-free emission. We present
a free-free emission dominated light curve model of V445 Pup on the basis of
the optically thick wind theory. Our light curve fitting shows that (1) the
white dwarf (WD) mass is very massive (M_WD \gtrsim 1.35 M_\sun), and (2) a
half of the accreted matter remains on the WD, both of which suggest that the
increasing WD mass. Therefore, V445 Pup is a strong candidate of Type Ia
supernova progenitor. The estimated distance to V445 Pup is now consistent with
the recent observational suggestions, 3.5 < d < 6.5 kpc. A helium star
companion is consistent with the brightness of m_v=14.5 mag just before the
outburst, if it is a little bit evolved hot (\log T (K) \gtrsim 4.5) star with
the mass of M_He \gtrsim 0.8 M_\sun. We then emphasize importance of
observations in the near future quiescent phase after the thick circumstellar
dust dissipates away, especially its color and magnitude to specify the nature
of the companion star. We have also calculated helium ignition masses for
helium shell flashes against various helium accretion rates and discussed the
recurrence period of helium novae.Comment: 8 pages including 12 figures, to appear in Ap
Entanglement Measures for Intermediate Separability of Quantum States
We present a family of entanglement measures R_m which act as indicators for
separability of n-qubit quantum states into m subsystems for arbitrary 2 \leq m
\leq n. The measure R_m vanishes if the state is separable into m subsystems,
and for m = n it gives the Meyer-Wallach measure while for m = 2 it reduces, in
effect, to the one introduced recently by Love et al. The measures R_m are
evaluated explicitly for the GHZ state and the W state (and its modifications,
the W_k states) to show that these globally entangled states exhibit rather
distinct behaviors under the measures, indicating the utility of the measures
R_m for characterizing globally entangled states as well.Comment: 8 pages, 8 figure
On local boundary CFT and non-local CFT on the boundary
The holographic relation between local boundary conformal quantum field
theories (BCFT) and their non-local boundary restrictions is reviewed, and
non-vacuum BCFT's, whose existence was conjectured previously, are constructed.Comment: 16 pages. Contribution to "Rigorous Quantum Field Theory", Symposium
in honour of J. Bros, Paris, July 2004. Based on joint work math-ph/0405067
with R. Long
Mathematical analysis of a model of river channel formation.
The study of overland flow of water over an erodible sediment leads to a coupled model describing the evolution of the topographic elevation and the depth of the overland water film. The spatially uniform solution of this model is unstable, and this instability corresponds to the formation of rills, which in reality then grow and coalesce to form large-scale river channels. In this paper we consider the deduction and mathematical analysis of a deterministic model describing river channel formation and the evolution of its depth. The model involves a degenerate nonlinear parabolic equation (satisfied on the interior of the support of the solution) with a super-linear source term and a prescribed constant mass. We propose here a global formulation of the problem (formulated in the whole space, beyond the support of the solution) which allows us to show the existence of a solution and leads to a suitable numerical scheme for its approximation. A particular novelty of the model is that the evolving channel self-determines its own width, without the need to pose any extra conditions at the channel margin
Quantized Anomalous Hall Effect in Two-Dimensional Ferromagnets - Quantum Hall Effect from Metal -
We study the effect of disorder on the anomalous Hall effect (AHE) in
two-dimensional ferromagnets. The topological nature of AHE leads to the
integer quantum Hall effect from a metal, i.e., the quantization of
induced by the localization except for the few extended states
carrying Chern number. Extensive numerical study on a model reveals that
Pruisken's two-parameter scaling theory holds even when the system has no gap
with the overlapping multibands and without the uniform magnetic field.
Therefore the condition for the quantized AHE is given only by the Hall
conductivity without the quantum correction, i.e., .Comment: 5 pages, 4 figures, REVTe
Analysis of nuclear transport signals in the human apurinic/apyrimidinic endonuclease (APE1/Ref1)
The mammalian abasic-endonuclease1/redox-factor1 (APE1/Ref1) is an essential protein whose subcellular distribution depends on the cellular physiological status. However, its nuclear localization signals have not been studied in detail. We examined nuclear translocation of APE1, by monitoring enhanced green fluorescent protein (EGFP) fused to APE1. APE1's nuclear localization was significantly decreased by deleting 20 amino acid residues from its N-terminus. Fusion of APE1's N-terminal 20 residues directed nuclear localization of EGFP. An APE1 mutant lacking the seven N-terminal residues (ND7 APE1) showed nearly normal nuclear localization, which was drastically reduced when the deletion was combined with the E12A/D13A double mutation. On the other hand, nearly normal nuclear localization of the full-length E12A/D13A mutant suggests that the first 7 residues and residues 8–13 can independently promote nuclear import. Both far-western analyses and immuno-pull-down assays indicate interaction of APE1 with karyopherin alpha 1 and 2, which requires the 20 N-terminal residues and implicates nuclear importins in APE1's nuclear translocation. Nuclear accumulation of the ND7 APE1(E12A/D13A) mutant after treatment with the nuclear export inhibitor leptomycin B suggests the presence of a previously unidentified nuclear export signal, and the subcellular distribution of APE1 may be regulated by both nuclear import and export
Local instability signatures in ALMA observations of dense gas in NGC7469
We present an unprecedented measurement of the disc stability and local
instability scales in the luminous infrared Seyfert 1 host, NGC7469, based on
ALMA observations of dense gas tracers and with a synthesized beam of 165 x 132
pc. While we confirm that non-circular motions are not significant in
redistributing the dense interstellar gas in this galaxy, we find compelling
evidence that the dense gas is a suitable tracer for studying the origin of its
intensely high-mass star forming ring-like structure. Our derived disc
stability parameter accounts for a thick disc structure and its value falls
below unity at the radii in which intense star formation is found. Furthermore,
we derive the characteristic instability scale and find a striking agreement
between our measured scale of ~ 180 pc, and the typical sizes of individual
complexes of young and massive star clusters seen in high-resolution images.Comment: Accepted for publication in ApJ Letter
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