5,284 research outputs found
Neuromodulation: present and emerging methods.
Neuromodulation has wide ranging potential applications in replacing impaired neural function (prosthetics), as a novel form of medical treatment (therapy), and as a tool for investigating neurons and neural function (research). Voltage and current controlled electrical neural stimulation (ENS) are methods that have already been widely applied in both neuroscience and clinical practice for neuroprosthetics. However, there are numerous alternative methods of stimulating or inhibiting neurons. This paper reviews the state-of-the-art in ENS as well as alternative neuromodulation techniques-presenting the operational concepts, technical implementation and limitations-in order to inform system design choices
Reward, punishment, and prosocial behavior: Recent developments and implications
Reward and punishment change the payoff structures of social interactions and therefore can potentially play a role in promoting prosocial behavior. Yet, there are boundary conditions for them to be effective. We review recent work that addresses the conditions under which rewards and punishment can enhance prosocial behavior, the proximate and ultimate mechanisms for individuals’ rewarding and punishing decisions, and the reputational and behavioral consequences of reward and punishment under noise. The reviewed evidence points to the importance of more field research on how reward and punishment can promote prosocial behavior in real-world settings. We also highlight the need to integrate different methodologies to better examine the effects of reward and punishment on prosocial behavior
Towards low-latency real-time detection of gravitational waves from compact binary coalescences in the era of advanced detectors
Electromagnetic (EM) follow-up observations of gravitational wave (GW) events
will help shed light on the nature of the sources, and more can be learned if
the EM follow-ups can start as soon as the GW event becomes observable. In this
paper, we propose a computationally efficient time-domain algorithm capable of
detecting gravitational waves (GWs) from coalescing binaries of compact objects
with nearly zero time delay. In case when the signal is strong enough, our
algorithm also has the flexibility to trigger EM observation before the merger.
The key to the efficiency of our algorithm arises from the use of chains of
so-called Infinite Impulse Response (IIR) filters, which filter time-series
data recursively. Computational cost is further reduced by a template
interpolation technique that requires filtering to be done only for a much
coarser template bank than otherwise required to sufficiently recover optimal
signal-to-noise ratio. Towards future detectors with sensitivity extending to
lower frequencies, our algorithm's computational cost is shown to increase
rather insignificantly compared to the conventional time-domain correlation
method. Moreover, at latencies of less than hundreds to thousands of seconds,
this method is expected to be computationally more efficient than the
straightforward frequency-domain method.Comment: 19 pages, 6 figures, for PR
Contact of Single Asperities with Varying Adhesion: Comparing Continuum Mechanics to Atomistic Simulations
Atomistic simulations are used to test the equations of continuum contact
mechanics in nanometer scale contacts. Nominally spherical tips, made by
bending crystals or cutting crystalline or amorphous solids, are pressed into a
flat, elastic substrate. The normal displacement, contact radius, stress
distribution, friction and lateral stiffness are examined as a function of load
and adhesion. The atomic scale roughness present on any tip made of discrete
atoms is shown to have profound effects on the results. Contact areas, local
stresses, and the work of adhesion change by factors of two to four, and the
friction and lateral stiffness vary by orders of magnitude. The microscopic
factors responsible for these changes are discussed. The results are also used
to test methods for analyzing experimental data with continuum theory to
determine information, such as contact area, that can not be measured directly
in nanometer scale contacts. Even when the data appear to be fit by continuum
theory, extracted quantities can differ substantially from their true values
A fully Bayesian semi-parametric scalar-on-function regression (SoFR) with measurement error using instrumental variables
Wearable devices such as the ActiGraph are now commonly used in health
studies to monitor or track physical activity. This trend aligns well with the
growing need to accurately assess the effects of physical activity on health
outcomes such as obesity. When accessing the association between these
device-based physical activity measures with health outcomes such as body mass
index, the device-based data is considered functions, while the outcome is a
scalar-valued. The regression model applied in these settings is the
scalar-on-function regression (SoFR). Most estimation approaches in SoFR assume
that the functional covariates are precisely observed, or the measurement
errors are considered random errors. Violation of this assumption can lead to
both under-estimation of the model parameters and sub-optimal analysis. The
literature on a measurement corrected approach in SoFR is sparse in the
non-Bayesian literature and virtually non-existent in the Bayesian literature.
This paper considers a fully nonparametric Bayesian measurement error corrected
SoFR model that relaxes all the constraining assumptions often made in these
models. Our estimation relies on an instrumental variable (IV) to identify the
measurement error model. Finally, we introduce an IV quality scalar parameter
that is jointly estimated along with all model parameters. Our method is easy
to implement, and we demonstrate its finite sample properties through an
extensive simulation. Finally, the developed methods are applied to the
National Health and Examination Survey to assess the relationship between
wearable-device-based measures of physical activity and body mass index among
adults living in the United States
On Galerkin approximations of the Navier-Stokes equations in the limit of large Grashof numbers
We examine how stationary solutions to Galerkin approximations of the
Navier--Stokes equations behave in the limit as the Grashof number tends to
. An appropriate scaling is used to place the Grashof number as a new
coefficient of the nonlinear term, while the body force is fixed. A new type of
asymptotic expansion, as , for a family of solutions is introduced.
Relations among the terms in the expansion are obtained by following a
procedure that compares and totally orders positive sequences generated by the
expansion. The same methodology applies to the case of perturbed body forces
and similar results are obtained. We demonstrate with a class of forces and
solutions that have convergent asymptotic expansions in . All the results
hold in both two and three dimensions, as well as for both no-slip and periodic
boundary conditions.Comment: 36 pp., corrections, accepted for publicatio
A scalable 32 channel neural recording and real-time FPGA based spike sorting system
This demo presents a scalable a 32-channel neural recording platform with real-time, on-node spike sorting ca- pability. The hardware consists of: an Intan RHD2132 neural amplifier; a low power Igloo ® nano FPGA; and an FX3 USB 3.0 controller. Graphical User Interfaces for controlling the system, displaying real-time data, and template generation with a modified form of WaveClus are demonstrated
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