126 research outputs found
Sensitivity to social exclusion in major depressive disorder (MDD) predicts therapeutic outcome after in-patient treatment
A
The association between work-related rumination and heart rate variability: A field study
This is the final version. Available on open access from Frontiers Media via the DOI in this recordThe objective of this study was to examine the association between perseverative cognition in the form of work-related rumination, and heart rate variability (HRV). We tested the hypothesis that high ruminators would show lower vagally mediated HRV relative to low ruminators during their leisure time. Individuals were classified as being low (n = 17) or high ruminators (n = 19), using the affective scale on the work-related rumination measure. HRV was assessed using a wrist sensor band (Microsoft Band 2). HRV was sampled between 8 pm and 10 pm over three workday evenings (Monday to Wednesday) while individuals carried out their normal evening routines. Compared to the low ruminators, high affective ruminators demonstrated lower HRV in the form of root mean square successive differences (RMSSDs), relative to the low ruminators, indicating lower parasympathetic activity. There was no significant difference in heart rate, or activity levels between the two groups during the recording periods. The current findings of this study may have implications for the design and delivery of interventions to help individuals unwind post work and to manage stress more effectively. Limitations and implications for future research are discussed
Automatic guiding of the primary image of solar Gregory telescopes
The primary image reflected from the field-stop of solar Gregory telescopes is used for automatic guiding. This new system avoids temporal varying influences from the bending of the telescope tube by the main mirror's gravity and
from offsets between the telescope and a separate guiding refractor. The required
stiffness of the guider mechanics and the small areas of the sensors demand small
f-numbers for the guider optics, which cause problems with the image quality and
with heat. Problems also arise from the imaging of the pinhole in the telescope's
field stop. The corresponding lack of image information at that location can be
reduced numerically by Fourier methods much more effectively than with profile
centering methods. Several types of such guiders are tested, a final equipment,
now installed at the Gregory telescopes at Tenerife and at Locarno, is described
CRISP Spectropolarimetric Imaging of Penumbral Fine Structure
We discuss penumbral fine structure in a small part of a pore, observed with
the CRISP imaging spectropolarimeter at the Swedish 1-m Solar Telescope (SST),
close to its diffraction limit of 0.16 arcsec. Milne-Eddington inversions
applied to these Stokes data reveal large variations of field strength and
inclination angle over dark-cored penumbral intrusions and a dark-cored light
bridge. The mid-outer part of this penumbra structure shows 0.3 arcsec wide
spines, separated by 1.6 arcsec (1200 km) and associated with 30 deg
inclination variations. Between these spines, there are no small-scale magnetic
structures that easily can be be identified with individual flux tubes. A
structure with nearly 10 deg more vertical and weaker magnetic field is seen
midways between two spines. This structure is co-spatial with the brightest
penumbral filament, possibly indicating the location of a convective upflow
from below.Comment: Accepted for publication in ApJL 17 Oct 2008. One Figure adde
Nonlinear vertical oscillations of a particle in a sheath of a rf discharge
A new simple method to measure the spatial distribution of the electric field
in the plasma sheath is proposed. The method is based on the experimental
investigation of vertical oscillations of a single particle in the sheath of a
low-pressure radio-frequency discharge. It is shown that the oscillations
become strongly nonlinear and secondary harmonics are generated as the
amplitude increases. The theory of anharmonic oscillations provides a good
qualitative description of the data and gives estimates for the first two
anharmonic terms in an expansion of the sheath potential around the particle
equilibrium.Comment: 11 pages, 4 figure
Vertical pairing of identical particles suspended in the plasma sheath
It is shown experimentally that vertical pairing of two identical
microspheres suspended in the sheath of a radio-frequency (rf) discharge at low
gas pressures (a few Pa), appears at a well defined instability threshold of
the rf power. The transition is reversible, but with significant hysteresis on
the second stage. A simple model, which uses measured microsphere resonance
frequencies and takes into account besides Coulomb interaction between
negatively charged microspheres also their interaction with positive ion wake
charges, seems to explain the instability threshold quite well.Comment: 4 pages, 6 figures. to appear in Phys. Rev. Lett. 86, May 14th (2001
Buildings behaving badly:A behavioral experiment on how different motivational frames influence residential energy label adoption in the Netherlands
Heating buildings contributes to approximately 36% of Europe’s energy demand and several EU member states have adopted mandatory energy labels to improve energy efficiency by promoting home weatherization investments. This paper focuses on the perception of the energy label for residential buildings in the Netherlands and the role of different frames (egoistic, biospheric and social norms and neutral frames) in motivating adoption of energy labels for housing. We used a behavioral email experiment and an online survey to investigate these motivational factors. We find that biospheric frames are weaker than the other three motivational frames in terms of engaging interest in the energy label, but that the biospheric frame results in higher willingness to pay (WTP) for the energy label. We also find that age (rather than income) correlates with higher willingness to pay for home energy labels
Stray-light contamination and spatial deconvolution of slit-spectrograph observations
Stray light caused by scattering on optical surfaces and in the Earth's
atmosphere degrades the spatial resolution of observations. We study the
contribution of stray light to the two channels of POLIS. We test the
performance of different methods of stray-light correction and spatial
deconvolution to improve the spatial resolution post-facto. We model the stray
light as having two components: a spectrally dispersed component and a
component of parasitic light caused by scattering inside the spectrograph. We
use several measurements to estimate the two contributions: observations with a
(partly) blocked FOV, a convolution of the FTS spectral atlas, imaging in the
pupil plane, umbral profiles, and spurious polarization signal in telluric
lines. The measurements allow us to estimate the spatial PSF of POLIS and the
main spectrograph of the German VTT. We use the PSF for a deconvolution of both
spectropolarimetric data and investigate the effect on the spectra. The
parasitic contribution can be directly and accurately determined for POLIS,
amounting to about 5%. We estimate a lower limit of about 10% across the full
FOV for the dispersed stray light. In quiet Sun regions, the stray-light level
from the close surroundings (d< 2") of a given spatial point is about 20%. The
stray light reduces to below 2% at a distance of 20" from a lit area for both
POLIS and the main spectrograph. A two-component model of the stray-light
contributions seems to be sufficient for a basic correction of observed
spectra. The instrumental PSF obtained can be used to model the off-limb stray
light, to determine the stray-light contamination accurately for observation
targets with large spatial intensity gradients such as sunspots, and also
allows one to improve the spatial resolution of observations post-facto.Comment: 14 pages, 16 figures, accepted by A&A. Version V2 revised for
language editin
Search for photospheric footpoints of quiet Sun transition region loops
CONTEXT:The footpoints of quiet Sun Transition Region (TR) loops do not seem
to coincide with the photospheric magnetic structures appearing in traditional
low-sensitivity magnetograms.
AIMS: To look for the so-far unidentified photospheric footpoints of TR loops
using G-band bright points (BPs) as proxies for photospheric magnetic field
concentrations.
METHODS: Comparison of TR measurements with SoHO/SUMER and photospheric
magnetic field observations obtained with the Dutch Open Telescope.
RESULTS: Photospheric BPs are associated with bright TR structures, but they
seem to avoid the brightest parts of the structure. BPs appear in regions that
are globally redshifted, but they avoid extreme velocities. TR explosive events
are not clearly associated with BPs.
CONCLUSIONS: The observations are not inconsistent with the BPs being
footpoints of TR loops, although we have not succeeded to uniquely identify
particular BPs with specific TR loops.Comment: Accepted for publication in A&A. 10 pages, 10 figures. Due to size
limitations, the quality of fig3 is not goo
ARTiiFACT: a tool for heart rate artifact processing and heart rate variability analysis
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