23,296 research outputs found
Circuit breaker utilizing magnetic latching relays Patent
Relay circuit breaker with magnetic latching to provide conductive and nonconductive paths for current device
The helical instability of the positive column in crossed fields and in annular plasma configurations Interim report
Helical instability of positive column in crossed fields and in annular plasma configuration
An x-band waveguide cell for study of microwave propagation through magnetoplasma technical report no. 16
Metal X-band waveguide cell for study of microwave propagation through magnetoplasm
Mixing of a passive scalar in isotropic and sheared homogeneous turbulence
In order to calculate the velocity and scalar fields, the three dimensional, time-dependent equations of motion and the diffusion equation were solved numerically. The following cases were treated: isotropic, homogeneous turbulence with decay of a passive scalar; and homogeneous turbulent shear flow with a passive scalar whose mean varies linearly in the spanwise direction. The solutions were obtained at relatively low Reynolds numbers so that all of the turbulent scales could be resolved without modeling. Turbulent statistics such as integral length scales, Taylor microscales, Kolmogorov length scale, one- and two-point correlations of velocity-velocity and velocity-scalar, turbulent Prandtl/Schmidt number, r.m.s. values of velocities, the scalar quantity and pressure, skewness, decay rates, and decay exponents were calculated. The results are compared with the available expermental results, and good agreement is obtained
The first-mover advantage in scientific publication
Mathematical models of the scientific citation process predict a strong
"first-mover" effect under which the first papers in a field will, essentially
regardless of content, receive citations at a rate enormously higher than
papers published later. Moreover papers are expected to retain this advantage
in perpetuity -- they should receive more citations indefinitely, no matter how
many other papers are published after them. We test this conjecture against
data from a selection of fields and in several cases find a first-mover effect
of a magnitude similar to that predicted by the theory. Were we wearing our
cynical hat today, we might say that the scientist who wants to become famous
is better off -- by a wide margin -- writing a modest paper in next year's
hottest field than an outstanding paper in this year's. On the other hand,
there are some papers, albeit only a small fraction, that buck the trend and
attract significantly more citations than theory predicts despite having
relatively late publication dates. We suggest that papers of this kind, though
they often receive comparatively few citations overall, are probably worthy of
our attention.Comment: 7 pages, 3 figure
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Internalisation of membrane progesterone receptor-α after treatment with progesterone: Potential involvement of a clathrin-dependent pathway
This article has been made available through the Brunel Open Access Publishing Fund.Internalisation and recycling of seven trans-membrane domain receptors is a critical regulatory event for their signalling. The mechanism(s) by which membrane progesterone receptor-α (mPRα) number is regulated on the cell surface is unclear. In this study, we investigated the cellular distribution of mPRα and mechanisms of mPRα trafficking using a cell line derived from a primary culture of human myometrial cells (M11) as an experimental model. RT-PCR and immunofluorescent analysis demonstrated expression of mPRα in M11 cells with mPRα primarily distributed on the cell surface under basal conditions. For the first time, plasma membrane localisation of mPRα was confirmed using immuno-gold transmission electron microscopy. Stimulation of M11 cells with progesterone (P4, 100 nM) resulted in internalisation of mPRα from the plasma membrane to the cytoplasm (10 min) and subsequent partial translocation back to the cell surface (20 min). We investigated potential endocytotic pathways involved in trafficking of mPRα after its internalisation. Partial co-localisation of clathrin with mPRα was obvious after 10 min of P4 treatment. Of note, chlorpromazine (inhibitor of clathrin-mediated pathway) inhibited the endocytosis of mPRα, whereas treatment with nystatin (inhibitor of caveolae-mediated pathway) did not affect internalisation. Collectively, these data suggest that mPRα is expressed on the cell surface of M11 cells and undergoes endocytosis after P4 stimulation primarily via a clathrin-mediated pathway.This article is available through the Brunel Open Access Publishing Fun
Parsec-scale radio morphology and variability of a changing-look AGN: the case of Mrk 590
We investigate the origin of the parsec-scale radio emission from the
changing-look active galactic nucleus (AGN) of Mrk 590, and examine whether the
radio power has faded concurrently with the dramatic decrease in accretion
rates observed between the 1990s and the present. We detect a compact core at
1.6 GHz and 8.4 GHz using new Very Long Baseline Array observations, finding no
significant extended, jet-like features down to 1 pc scales. The flat
spectral index () and high brightness temperature
() indicate self-absorbed synchrotron emission
from the AGN. The radio to X-ray luminosity ratio of , similar to that in coronally active stars, suggests
emission from magnetized coronal winds, although unresolved radio jets are also
consistent with the data. Comparing new Karl G. Jansky Very Large Array
measurements with archival and published radio flux densities, we find ,
, and (insignificantly) flux density decreases between the 1990s
and the year 2015 at 1.4 GHz, 5 GHz and 8.4 GHz respectively. This trend,
possibly due to the expansion and fading of internal shocks within the
radio-emitting outflow after a recent outburst, is consistent with the decline
of the optical-UV and X-ray luminosities over the same period. Such correlated
variability demonstrates the AGN accretion-outflow connection, confirming that
the changing-look behaviour in Mrk 590 originates from variable accretion rates
rather than dust obscuration. The present radio and X-ray luminosity
correlation, consistent with low/hard state accretion, suggests that the black
hole may now be accreting in a radiatively inefficient mode.Comment: 14 pages, 5 tables, 5 figures, accepted for publication in MNRA
Plant Disease Outlook for 1969
Knowledge of carryover inoculum is by itself insufficient to predict this year\u27s disease attacks. Two botanists and plant pathologists analyze a number of environmental factors in recommending preventive control measures for 1969
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