4,011 research outputs found
Further development in theory/data closure of the photoelectron-driven polar wind and day-night transition of the outflow
Correction to: Further development in theory/data closure of the photoelectron-driven polar wind and day-night transition of the outflow
A sandpile model with tokamak-like enhanced confinement phenomenology
Confinement phenomenology characteristic of magnetically confined plasmas
emerges naturally from a simple sandpile algorithm when the parameter
controlling redistribution scalelength is varied. Close analogues are found for
enhanced confinement, edge pedestals, and edge localised modes (ELMs), and for
the qualitative correlations between them. These results suggest that tokamak
observations of avalanching transport are deeply linked to the existence of
enhanced confinement and ELMs.Comment: Manuscript is revtex (latex) 1 file, 7 postscript figures Revised
version is final version accepted for publication in PRL Revisions are mino
IRE1ÎČ negatively regulates IRE1α signaling in response to endoplasmic reticulum stress
IRE1ÎČ is an ER stress sensor uniquely expressed in epithelial cells lining mucosal surfaces. Here, we show that intestinal epithelial cells expressing IRE1ÎČ have an attenuated unfolded protein response to ER stress. When modeled in HEK293 cells and with purified protein, IRE1ÎČ diminishes expression and inhibits signaling by the closely related stress sensor IRE1α. IRE1ÎČ can assemble with and inhibit IRE1α to suppress stress-induced XBP1 splicing, a key mediator of the unfolded protein response. In comparison to IRE1α, IRE1ÎČ has relatively weak XBP1 splicing activity, largely explained by a nonconserved amino acid in the kinase domain active site that impairs its phosphorylation and restricts oligomerization. This enables IRE1ÎČ to act as a dominant-negative suppressor of IRE1α and affect how barrier epithelial cells manage the response to stress at the hostâenvironment interface
Arase Observation of the Source Region of Auroral Arcs and Diffuse Auroras in the Inner Magnetosphere
Auroral arcs and diffuse auroras are common phenomena at high latitudes, though characteristics of their source plasma and fields have not been well understood. We report the first observation of fields and particles including their pitchâangle distributions in the source region of auroral arcs and diffuse auroras, using data from the Arase satellite at L ~ 6.0â6.5. The auroral arcs appeared and expanded both poleward and equatorward at local midnight from ~0308 UT on 11 September 2018 at Nain (magnetic latitude: 66°), Canada, during the expansion phase of a substorm, while diffuse auroras covered the whole sky after 0348 UT. The top part of auroral arcs was characterized by purple/blue emissions. Bidirectional fieldâaligned electrons with structured energyâtime spectra were observed in the source region of auroral arcs, while source electrons became isotropic and less structured in the diffuse auroral region afterwards. We suggest that structured bidirectional electrons at energies below a few keV were caused by upward fieldâaligned potential differences (upward electric field along geomagnetic field) reaching high altitudes (~30,000 km) above Arase. The bidirectional electrons above a few keV were probably caused by Fermi acceleration associated with the observed field dipolarization. Strong electricâfield fluctuations and earthward Poynting flux were observed at the arc crossing and are probably also caused by the field dipolarization. The ions showed timeâpitchâangle dispersion caused by mirror reflection. These results indicate a clear contrast between auroral arcs and diffuse auroras in terms of source plasma and fields and generation mechanisms of auroral arcs in the inner magnetosphere
A side-by-side comparison of Daya Bay antineutrino detectors
The Daya Bay Reactor Neutrino Experiment is designed to determine precisely
the neutrino mixing angle with a sensitivity better than 0.01 in
the parameter sin at the 90% confidence level. To achieve this
goal, the collaboration will build eight functionally identical antineutrino
detectors. The first two detectors have been constructed, installed and
commissioned in Experimental Hall 1, with steady data-taking beginning
September 23, 2011. A comparison of the data collected over the subsequent
three months indicates that the detectors are functionally identical, and that
detector-related systematic uncertainties exceed requirements.Comment: 24 pages, 36 figure
Observation of electron-antineutrino disappearance at Daya Bay
The Daya Bay Reactor Neutrino Experiment has measured a non-zero value for
the neutrino mixing angle with a significance of 5.2 standard
deviations. Antineutrinos from six 2.9 GW reactors were detected in
six antineutrino detectors deployed in two near (flux-weighted baseline 470 m
and 576 m) and one far (1648 m) underground experimental halls. With a 43,000
ton-GW_{\rm th}-day livetime exposure in 55 days, 10416 (80376) electron
antineutrino candidates were detected at the far hall (near halls). The ratio
of the observed to expected number of antineutrinos at the far hall is
. A rate-only analysis
finds in a
three-neutrino framework.Comment: 5 figures. Version to appear in Phys. Rev. Let
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