2,166 research outputs found
Partial redistribution effects in the formation of hydrogen lines in quiescent prominences
Departures from complete frequency redistribution (CRD) in hydrogen lines are investigated for solar prominences. Partial redistribution effects (PRD) are found both in the wings (their already known lowering) and in the central part of the L alpha line; a new feature is evidenced here: the partially coherent scattering in the near wings of the line leads to a double-peaked profile mirroring the incident solar radiation. With a low density model, we obtain a good agreement with OSO 8 observed profiles. On the contrary, the PRD computed L beta profile (lower density, no reversal) departs from the observed one, a result which calls for more progress in terms of non-LTE transfer and modelling
Atmosphere above a large solar pore
A large solar pore with a granular light bridge was observed on October 15,
2008 with the IBIS spectrometer at the Dunn Solar Telescope and a 69-min long
time series of spectral scans in the lines Ca II 854.2 nm and Fe I 617.3 nm was
obtained. The intensity and Doppler signals in the Ca II line were separated.
This line samples the middle chromosphere in the core and the middle
photosphere in the wings. Although no indication of a penumbra is seen in the
photosphere, an extended filamentary structure, both in intensity and Doppler
signals, is observed in the Ca II line core. An analysis of morphological and
dynamical properties of the structure shows a close similarity to a
superpenumbra of a sunspot with developed penumbra. A special attention is paid
to the light bridge, which is the brightest feature in the pore seen in the Ca
II line centre and shows an enhanced power of chromospheric oscillations at 3-5
mHz. Although the acoustic power flux in the light bridge is five times higher
than in the "quiet" chromosphere, it cannot explain the observed brightness.Comment: 6 pages, 3 figures, accepted in Journal of Physics: Conference Serie
The Impact of Gender-Biased Language in State Regulations Upon Judgments About Foster Children
This study investigated the impact of gender-biased language in the wording of state regulations governing the treatment of foster children in Illinois. Participants were given excerpts of legal language written with either gender-biased or gender-inclusive language and then asked to judge a hypothetical situation involving a male or a female child. It was hypothesized that gender-biased language would have differential effects on interpretation of the language for boys versus girls; we also proposed a moderated mediation model that hypothesized activation of gendered constructs would mediate the interpretation of gendered language. According to the hypothesized model, participant sexism and attitudes towards gender-biased language would moderate these relationships. Analyses were conducted using data collected from 274 participants using an online survey on Amazon’s Mechanical Turk. Analyses did not support our main hypotheses; language type and gender of child did not significantly affect participant evaluations of the hypothetical scenario, and the hypothesized moderated mediation model was not supported. Possible explanations for these findings and future directions are discussed
Hydrogen Balmer line formation in solar flares affected by return currents
Aims. We investigate the effect of the electric return currents in solar
flares on the profiles of hydrogen Balmer lines. We consider the monoenergetic
approximation for the primary beam and runaway model of the neutralizing return
current. Methods. Propagation of the 10 keV electron beam from a coronal
reconnection site is considered for the semiempirical chromosphere model F1. We
estimate the local number density of return current using two approximations
for beam energy fluxes between and . Inelastic collisions of beam and return-current electrons
with hydrogen are included according to their energy distributions, and the
hydrogen Balmer line intensities are computed using an NLTE radiative transfer
approach. Results. In comparison to traditional NLTE models of solar flares
that neglect the return-current effects, we found a significant increase
emission in the Balmer line cores due to nonthermal excitation by return
current. Contrary to the model without return current, the line shapes are
sensitive to a beam flux. It is the result of variation in the return-current
energy that is close to the hydrogen excitation thresholds and the density of
return-current electrons.Comment: 4 pages, 3 figures, 1 table, accepted for publication in Astronomy
and Astrophysics Letter
Spin States in Graphene Quantum Dots
We investigate ground and excited state transport through small (d = 70 nm)
graphene quantum dots. The successive spin filling of orbital states is
detected by measuring the ground state energy as a function of a magnetic
field. For a magnetic field in-plane of the quantum dot the Zemann splitting of
spin states is measured. The results are compatible with a g-factor of 2 and we
detect a spin-filling sequence for a series of states which is reasonable given
the strength of exchange interaction effects expected for graphene
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