1,096 research outputs found
Low-cost, smartphone-based instant three-dimensional registration system for infant functional near-infrared spectroscopy applications
Significance
To effectively apply functional near-infrared spectroscopy (fNIRS)/diffuse optical tomography (DOT) devices, a three-dimensional (3D) model of the position of each optode on a subject’s scalp and the positions of that subject’s cranial landmarks are critical. Obtaining this information accurately in infants, who rarely stop moving, is an ongoing challenge.
Aim
We propose a smartphone-based registration system that can potentially achieve a full-head 3D scan of a 6-month-old infant instantly.
Approach
The proposed system is remotely controlled by a custom-designed Bluetooth controller. The scanned images can either be manually or automatically aligned to generate a 3D head surface model.
Results
A full-head 3D scan of a 6-month-old infant can be achieved within 2 s via this system. In testing on a realistic but static infant head model, the average Euclidean error of optode position using this device was 1.8 mm.
Conclusions
This low-cost 3D registration system therefore has the potential to permit accurate and near-instant fNIRS/DOT spatial registration
Breakdown of C3 complement and IgG in peritonitis exudate-pathophysiological aspects and therapeutic approach
Mapping quantum-classical Liouville equation: projectors and trajectories
The evolution of a mixed quantum-classical system is expressed in the mapping
formalism where discrete quantum states are mapped onto oscillator states,
resulting in a phase space description of the quantum degrees of freedom. By
defining projection operators onto the mapping states corresponding to the
physical quantum states, it is shown that the mapping quantum-classical
Liouville operator commutes with the projection operator so that the dynamics
is confined to the physical space. It is also shown that a trajectory-based
solution of this equation can be constructed that requires the simulation of an
ensemble of entangled trajectories. An approximation to this evolution equation
which retains only the Poisson bracket contribution to the evolution operator
does admit a solution in an ensemble of independent trajectories but it is
shown that this operator does not commute with the projection operators and the
dynamics may take the system outside the physical space. The dynamical
instabilities, utility and domain of validity of this approximate dynamics are
discussed. The effects are illustrated by simulations on several quantum
systems.Comment: 4 figure
Correction to: ‘Robert Provine: the critical human importance of laughter, connections and contagion’ (2022) by Scott et al
One of the authors' names was spelt incorrectly as Addsion Billing instead of Addison Billing. This has now been corrected on the publisher's website
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