1,597 research outputs found
The upper-atmosphere extension of the ICON general circulation model (version: Ua-icon-1.0)
How the upper-atmosphere branch of the circulation contributes to and interacts with the circulation of the middle and lower atmosphere is a research area with many open questions. Inertia-gravity waves, for instance, have moved in the focus of research as they are suspected to be key features in driving and shaping the circulation. Numerical atmospheric models are an important pillar for this research. We use the ICOsahedral Non-hydrostatic (ICON) general circulation model, which is a joint development of the Max Planck Institute for Meteorology (MPI-M) and the German Weather Service (DWD), and provides, e.g., local mass conservation, a flexible grid nesting option, and a non-hydrostatic dynamical core formulated on an icosahedral-triangular grid. We extended ICON to the upper atmosphere and present here the two main components of this new configuration named UA-ICON: an extension of the dynamical core from shallow- to deep-atmosphere dynamics and the implementation of an upper-atmosphere physics package. A series of idealized test cases and climatological simulations is performed in order to evaluate the upper-atmosphere extension of ICON. © Author(s) 2019
Assessing blood brain barrier dynamics or identifying or measuring selected substances, including ethanol or toxins, in a subject by analyzing Raman spectrum signals
A non-invasive method for analyzing the blood-brain barrier includes obtaining a Raman spectrum of a selected portion of the eye and monitoring the Raman spectrum to ascertain a change to the dynamics of the blood brain barrier.Also, non-invasive methods for determining the brain or blood level of an analyte of interest, such as glucose, drugs, alcohol, poisons, and the like, comprises: generating an excitation laser beam at a selected wavelength (e.g., at a wavelength of about 400 to 900 nanometers); focusing the excitation laser beam into the anterior chamber of an eye of the subject so that aqueous humor, vitreous humor, or one or more conjunctiva vessels in the eye is illuminated; detecting (preferably confocally detecting) a Raman spectrum from the illuminated portion of the eye; and then determining the blood level or brain level (intracranial or cerebral spinal fluid level) of an analyte of interest for the subject from the Raman spectrum. In certain embodiments, the detecting step may be followed by the step of subtracting a confounding fluorescence spectrum from the Raman spectrum to produce a difference spectrum; and determining the blood level and/or brain level of the analyte of interest for the subject from that difference spectrum, preferably using linear or nonlinear multivariate analysis such as partial least squares analysis. Apparatus for carrying out the foregoing methods are also disclosed
Non-invasive method of measuring cerebral spinal fluid pressure
The invention provides a method of non-invasively determining intracranial pressure from measurements of an eye. A parameter of an optic nerve of the eye is determined, along with an intraocular pressure of the eye. The intracranial pressure may be determined from the intraocular pressure and the parameter
Non-invasive glucose monitor
A non-invasive method for determining blood level of an analyte of interest, such as glucose, comprises: generating an excitation laser beam (e.g., at a wavelength of 700 to 900 nanometers); focusing the excitation laser beam into the anterior chamber of an eye of the subject so that aqueous humor in the anterior chamber is illuminated; detecting (preferably confocally detecting) a Raman spectrum from the illuminated aqueous humor; and then determining the blood glucose level (or the level of another analyte of interest) for the subject from the Raman spectrum. Preferably, the detecting step is followed by the step of subtracting a confounding fluorescence spectrum from the Raman spectrum to produce a difference spectrum; and determining the blood level of the analyte of interest for the subject from that difference spectrum, preferably using linear or nonlinear multivariate analysis such as partial least squares analysis. Apparatus for carrying out the foregoing method is also disclosed
Evaluating Atypical Gaze Patterns through Vision Models: The Case of Cortical Visual Impairment
A wide range of neurological and cognitive disorders exhibit distinct
behavioral markers aside from their clinical manifestations. Cortical Visual
Impairment (CVI) is a prime example of such conditions, resulting from damage
to visual pathways in the brain, and adversely impacting low- and high-level
visual function. The characteristics impacted by CVI are primarily described
qualitatively, challenging the establishment of an objective, evidence-based
measure of CVI severity. To study those characteristics, we propose to create
visual saliency maps by adequately prompting deep vision models with attributes
of clinical interest. After extracting saliency maps for a curated set of
stimuli, we evaluate fixation traces on those from children with CVI through
eye tracking technology. Our experiments reveal significant gaze markers that
verify clinical knowledge and yield nuanced discriminability when compared to
those of age-matched control subjects. Using deep learning to unveil atypical
visual saliency is an important step toward establishing an eye-tracking
signature for severe neurodevelopmental disorders, like CVI.Comment: 5 pages, 4 figures, submitted to IEEE EMBC 202
Nuclear effects in atomic transitions
Atomic electrons are sensitive to the properties of the nucleus they are
bound to, such as nuclear mass, charge distribution, spin, magnetization
distribution, or even excited level scheme. These nuclear parameters are
reflected in the atomic transition energies. A very precise determination of
atomic spectra may thus reveal information about the nucleus, otherwise hardly
accessible via nuclear physics experiments. This work reviews theoretical and
experimental aspects of the nuclear effects that can be identified in atomic
structure data. An introduction to the theory of isotope shifts and hyperfine
splitting of atomic spectra is given, together with an overview of the typical
experimental techniques used in high-precision atomic spectroscopy. More exotic
effects at the borderline between atomic and nuclear physics, such as parity
violation in atomic transitions due to the weak interaction, or nuclear
polarization and nuclear excitation by electron capture, are also addressed.Comment: review article, 53 pages, 14 figure
What can the activation energy tell about the energetics at grain boundaries in polycrystalline organic films?
Charge-carrier transport at the semiconductor-gate dielectric interface in
organic field-effect transistors is critically dependent on the degree of
disorder in the typically semi-crystalline semiconductor layer. Charge trapping
can occur at the interface as well as in the current-carrying semiconductor
layer itself. A detailed and systematic understanding of the role of grain
boundaries between crystallites and how to avoid their potentially detrimental
effects is still an important focus of research in the organic electronics
community. A typical macroscopic measurement technique to extract information
about the energetics of the grain boundaries is an activation energy
measurement. Here, we compare detailed experiments on the energetic properties
of monolayer thin films implemented in organic field-effect transistors, having
controlled numbers of grain boundaries within the channel region to kinetic
Monte-Carlo simulations of charge-carrier transport to elucidate the influence
of grain boundaries on the extracted activation energies. Two important
findings are: 1) whereas the energy at the grain boundary does not change with
the number of grain boundaries in a thin film, both the measured and simulated
activation energy increases with the number of grain boundaries. 2) In
simulations where both energy barriers and valleys are present at the grain
boundaries there is no systematic relation between the number of grain
boundaries and extracted activation energies. We conclude, that a macroscopic
measurement of the activation energy can serve as general quality indicator of
the thin film, but does not allow microscopic conclusions about the energy
landscape of the thin film
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