7,640 research outputs found
High-order accurate difference schemes for the Hodgkin-Huxley equations
A novel approach for simulating potential propagation in neuronal branches
with high accuracy is developed. The method relies on high-order accurate
difference schemes using the Summation-By-Parts operators with weak boundary
and interface conditions applied to the Hodgkin-Huxley equations. This work is
the first demonstrating high accuracy for that equation. Several boundary
conditions are considered including the non-standard one accounting for the
soma presence, which is characterized by its own partial differential equation.
Well-posedness for the continuous problem as well as stability of the discrete
approximation is proved for all the boundary conditions. Gains in terms of CPU
times are observed when high-order operators are used, demonstrating the
advantage of the high-order schemes for simulating potential propagation in
large neuronal trees
Effects of Economic Policies Aimed at Encouraging a Healthier Grain Consumption
In this paper, we evaluate the effects of policy reforms aimed at achieving two policy objectives for grain consumption; (a) to double the intake of bread and breakfast cereals and (b) to ensure that half of the bread and breakfast cereals consumed are whole grain products. The overall aim of these policy objectives are to increase the dietary fibre intake from grain consumption so as to significantly contribute to the general recommended (minimum) increase of the fibre intake. Based on parameter estimates from a demand system we simulate the resulting changes in volumes purchased and fibre intake from two policy reforms entailing differentiated VAT on grain products. In the first reform we remove the VAT on "keyhole labelled" bread and breakfast cereals, in the second reform we consider a more extensive policy package of subsidizing the keyhole labelled bread and breakfast cereals by 20 percent while removing the VAT on all other grain products. Our results indicate that both reforms are likely to be successful in ensuring that the consumers attain the nutrition recommendations that half of the bread and breakfast cereals consumed are whole grain products, but that additional policy instruments are needed to reach the recommendation that the intake of bread and breakfast cereals should be doubled.Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety,
Discretization of the Superparticle Path Integral
Requiring that the path integral has the global symmetries of the classical
action and obeys the natural composition property of path integrals, and also
that the discretized action has the correct naive continuum limit, we find a
viable discretization of the (D=3,N=2) superparticle action.Comment: 10 page
The Relaxed Edge-Coloring Game and \u3cem\u3ek\u3c/em\u3e-Degenerate Graphs
The (r, d)-relaxed edge-coloring game is a two-player game using r colors played on the edge set of a graph G. We consider this game on forests and more generally, on k-degenerate graphs. If F is a forest with â(F) = â, then the first player, Alice, has a winning strategy for this game with r = â â j and d â„ 2j + 2 for 0 †j †â â 1. This both improves and generalizes the result for trees in [10]. More broadly, we generalize the main result in [10] by showing that if G is k-degenerate with â(G) = â and j â [â + k â 1], then there exists a function h(k, j) such that Alice has a winning strategy for this game with r = â + k â j and d â„ h(k, j)
Giving top quark effective operators a boost
We investigate the prospects to systematically improve generic effective
field theory-based searches for new physics in the top sector during LHC run 2
as well as the high luminosity phase. In particular, we assess the benefits of
high momentum transfer final states on top EFT-fit as a function of systematic
uncertainties in comparison with sensitivity expected from fully-resolved
analyses focusing on production. We find that constraints are
typically driven by fully-resolved selections, while boosted top quarks can
serve to break degeneracies in the global fit. This demystifies and clarifies
the importance of high momentum transfer final states for global fits to new
interactions in the top sector from direct measurements.Comment: Published versio
A Microstructural View of Burrowing with RoboClam
RoboClam is a burrowing technology inspired by Ensis directus, the Atlantic
razor clam. Atlantic razor clams should only be strong enough to dig a few
centimeters into the soil, yet they burrow to over 70 cm. The animal uses a
clever trick to achieve this: by contracting its body, it agitates and locally
fluidizes the soil, reducing the drag and energetic cost of burrowing. RoboClam
technology, which is based on the digging mechanics of razor clams, may be
valuable for subsea applications that could benefit from efficient burrowing,
such as anchoring, mine detonation, and cable laying. We directly visualize the
movement of soil grains during the contraction of RoboClam, using a novel
index-matching technique along with particle tracking. We show that the size of
the failure zone around contracting RoboClam, can be theoretically predicted
from the substrate and pore fluid properties, provided that the timescale of
contraction is sufficiently large. We also show that the nonaffine motions of
the grains are a small fraction of the motion within the fluidized zone,
affirming the relevance of a continuum model for this system, even though the
grain size is comparable to the size of RoboClam
- âŠ