8,120 research outputs found
Sleep to Upscale, Sleep to Downscale: Balancing Homeostasis and Plasticity
The synaptic homeostasis hypothesis of sleep proposes that slow wave sleep (SWS) causes downscaling of synaptic networks potentiated during information uptake in prior wakefulness. Two studies in Neuron challenge this mechanism. Chauvette et al. (2012) show that SWS mediates an up- rather than downregulation of excitatory postsynaptic potential responses. Grosmark et al. (2012) find that downscaling in hippocampal networks might be mediated through REM sleep theta rather than SWS
Interferometric phase-dispersion microscopy
We describe a new scanning microscopy technique, phase-dispersion microscopy (PDM). The technique is based on measuring the phase difference between the fundamental and the second-harmonic light in a novel interferometer. PDM is highly sensitive to subtle refractive-index differences that are due to dispersion (differential optical path sensitivity, 5 nm). We apply PDM to measure minute amounts of DNA in solution and to study biological tissue sections. We demonstrate that PDM performs better than conventional phase-contrast microscopy in imaging dispersive and weakly scattering samples
A two-dimensional Fermi liquid with attractive interactions
We realize and study an attractively interacting two-dimensional Fermi
liquid. Using momentum resolved photoemission spectroscopy, we measure the
self-energy, determine the contact parameter of the short-range interaction
potential, and find their dependence on the interaction strength. We
successfully compare the measurements to a theoretical analysis, properly
taking into account the finite temperature, harmonic trap, and the averaging
over several two-dimensional gases with different peak densities
Decentralization in Bitcoin and Ethereum Networks
Blockchain-based cryptocurrencies have demonstrated how to securely implement
traditionally centralized systems, such as currencies, in a decentralized
fashion. However, there have been few measurement studies on the level of
decentralization they achieve in practice. We present a measurement study on
various decentralization metrics of two of the leading cryptocurrencies with
the largest market capitalization and user base, Bitcoin and Ethereum. We
investigate the extent of decentralization by measuring the network resources
of nodes and the interconnection among them, the protocol requirements
affecting the operation of nodes, and the robustness of the two systems against
attacks. In particular, we adapted existing internet measurement techniques and
used the Falcon Relay Network as a novel measurement tool to obtain our data.
We discovered that neither Bitcoin nor Ethereum has strictly better properties
than the other. We also provide concrete suggestions for improving both
systems.Comment: Financial Cryptography and Data Security 201
Validation of Kalman Filter alignment algorithm with cosmic-ray data using a CMS silicon strip tracker endcap
A Kalman Filter alignment algorithm has been applied to cosmic-ray data. We
discuss the alignment algorithm and an experiment-independent implementation
including outlier rejection and treatment of weakly determined parameters.
Using this implementation, the algorithm has been applied to data recorded with
one CMS silicon tracker endcap. Results are compared to both photogrammetry
measurements and data obtained from a dedicated hardware alignment system, and
good agreement is observed.Comment: 11 pages, 8 figures. CMS NOTE-2010/00
- …