117,007 research outputs found
An improved method for estimating the neutron background in measurements of neutron capture reactions
The relation between the neutron background in neutron capture measurements
and the neutron sensitivity related to the experimental setup is examined. It
is pointed out that a proper estimate of the neutron background may only be
obtained by means of dedicated simulations taking into account the full
framework of the neutron-induced reactions and their complete temporal
evolution. No other presently available method seems to provide reliable
results, in particular under the capture resonances. An improved neutron
background estimation technique is proposed, the main improvement regarding the
treatment of the neutron sensitivity, taking into account the temporal
evolution of the neutron-induced reactions. The technique is complemented by an
advanced data analysis procedure based on relativistic kinematics of neutron
scattering. The analysis procedure allows for the calculation of the neutron
background in capture measurements, without requiring the time-consuming
simulations to be adapted to each particular sample. A suggestion is made on
how to improve the neutron background estimates if neutron background
simulations are not available.Comment: 11 pages, 9 figure
LHC Results - Highlights
The LHC has delivered already 10/fb of proton proton collisions at a centre-
of-mass energy of 7-8 TeV. With this data set, ATLAS and CMS have discovered a
new boson at a mass of about 125 GeV and have searched for new physics at the
TeV scale.Comment: 13 pages, Lecture given at the 2012 European School of High-Energy
Physics, Anjou, France, 6-9 June 201
Adaptive response and enlargement of dynamic range
Many membrane channels and receptors exhibit adaptive, or desensitized,
response to a strong sustained input stimulus, often supported by protein
activity-dependent inactivation. Adaptive response is thought to be related to
various cellular functions such as homeostasis and enlargement of dynamic range
by background compensation. Here we study the quantitative relation between
adaptive response and background compensation within a modeling framework. We
show that any particular type of adaptive response is neither sufficient nor
necessary for adaptive enlargement of dynamic range. In particular a precise
adaptive response, where system activity is maintained at a constant level at
steady state, does not ensure a large dynamic range neither in input signal nor
in system output. A general mechanism for input dynamic range enlargement can
come about from the activity-dependent modulation of protein responsiveness by
multiple biochemical modification, regardless of the type of adaptive response
it induces. Therefore hierarchical biochemical processes such as methylation
and phosphorylation are natural candidates to induce this property in signaling
systems.Comment: Corrected typos, minor text revision
Exploration vs Exploitation vs Safety: Risk-averse Multi-Armed Bandits
Motivated by applications in energy management, this paper presents the
Multi-Armed Risk-Aware Bandit (MARAB) algorithm. With the goal of limiting the
exploration of risky arms, MARAB takes as arm quality its conditional value at
risk. When the user-supplied risk level goes to 0, the arm quality tends toward
the essential infimum of the arm distribution density, and MARAB tends toward
the MIN multi-armed bandit algorithm, aimed at the arm with maximal minimal
value. As a first contribution, this paper presents a theoretical analysis of
the MIN algorithm under mild assumptions, establishing its robustness
comparatively to UCB. The analysis is supported by extensive experimental
validation of MIN and MARAB compared to UCB and state-of-art risk-aware MAB
algorithms on artificial and real-world problems.Comment: 16 page
The Basle securitisation framework explained: the regulatory treatment of asset securitisation : (forthcoming in Journal of Financial Regulation and Compliance, Vol. 13, No. 1)
The paper provides a comprehensive overview of the gradual evolution of the supervisory policy adopted by the Basle Committee for the regulatory treatment of asset securitisation. We carefully highlight the pathology of the new “securitisation framework” to facilitate a general understanding of what constitutes the current state of computing adequate capital requirements for securitised credit exposures. Although we incorporate a simplified sensitivity analysis of the varying levels of capital charges depending on the security design of asset securitisation transactions, we do not engage in a profound analysis of the benefits and drawbacks implicated in the new securitisation framework. JEL Klassifikation: E58, G21, G24, K23, L51. Forthcoming in Journal of Financial Regulation and Compliance, Vol. 13, No. 1
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