982 research outputs found
A compilation of known QSOs for the Gaia mission
Quasars are essential for astrometric in the sense that they are spatial
stationary because of their large distance from the Sun. The European Space
Agency (ESA) space astrometric satellite Gaia is scanning the whole sky with
unprecedented accuracy up to a few muas level. However, Gaia's two fields of
view observations strategy may introduce a parallax bias in the Gaia catalog.
Since it presents no significant parallax, quasar is perfect nature object to
detect such bias. More importantly, quasars can be used to construct a
Celestial Reference Frame in the optical wavelengths in Gaia mission. In this
paper, we compile the most reliable quasars existing in literatures. The final
compilation (designated as Known Quasars Catalog for Gaia mission, KQCG)
contains 1843850 objects, among of them, 797632 objects are found in Gaia DR1
after cross-identifications. This catalog will be very useful in Gaia mission
Ceria–terbia solid solution nanobelts with high catalytic activities for CO oxidation
Ceria–terbia solid solution nanobelts were prepared by an electrochemical route and tested as catalysts of high activity for CO oxidation
Numerical investigation and design of aluminium alloy channel section columns at elevated temperatures
Parkinson's disease deficits in time perception to auditory as well as visual stimuli - A large online study
Cognitive deficits are common in Parkinson’s disease (PD) and range from mild cognitive impairment to dementia, often dramatically reducing quality of life. Physiological models have shown that attention and memory are predicated on the brain’s ability to process time. Perception has been shown to be increased or decreased by activation or deactivation of dopaminergic neurons respectively. Here we investigate differences in time perception between patients with PD and healthy controls. We have measured differences in sub-second- and second-time intervals. Sensitivity and error in perception as well as the response times are calculated. Additionally, we investigated intra-individual response variability and the effect of participant devices on both reaction time and sensitivity. Patients with PD have impaired sensitivity in discriminating between durations of both visual and auditory stimuli compared to healthy controls. Though initially designed as an in-person study, because of the pandemic the experiment was adapted into an online study. This adaptation provided a unique opportunity to enroll a larger number of international participants and use this study to evaluate the feasibility of future virtual studies focused on cognitive impairment. To our knowledge this is the only time perception study, focusing on PD, which measures the differences in perception using both auditory and visual stimuli. The cohort involved is the largest to date, comprising over 800 participants
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