52,472 research outputs found
Origin of Borromean systems
The complex energies of the three-body resonances for one infinitely heavy
particle and two non-interacting light particles are the sum of the two
contributing two-body complex resonance energies. The bound state of a
Borromean system originates from a resonance when the third interaction is
introduced, a finite mass is allowed and proper angular momentum coupling is
included. The relative importance of these contributions are investigated and
the resulting structure of Borromean systems are traced back to the two-body
continuum properties. The and states in He result from
neutron-core p-states and the ground and first excited state of Li
originate from neutron-core and -states.Comment: Physics Letters B, in pres
Momentum distributions and reaction mechanisms for breakup of two--neutron halos
A theoretical model able to describe fragmentation reactions of three--body
halo nuclei on different targets, from light to heavy, is used to compute
neutron and core momentum distributions. Both Coulomb and nuclear interactions
are simultaneously included. We specify the different reaction mechanisms
related to various processes. The method is applied to fragmentation of He
and Li on C and Pb. We find good agreement with the available
experimental results.Comment: 10 pages, 3 figures, Phys.Lett.B in pres
Resonances in three-body systems with short and long-range interactions
The complex scaling method permits calculations of few-body resonances with
the correct asymptotic behaviour using a simple box boundary condition at a
sufficiently large distance. This is also valid for systems involving more than
one charged particle. We first apply the method on two-body systems. Three-body
systems are then investigated by use of the (complex scaled) hyperspheric
adiabatic expansion method. The case of the 2 resonance in Be and
Li is considered. Radial wave functions are obtained showing the correct
asymptotic behaviour at intermediate values of the hyperradii, where wave
functions can be computed fully numerically.Comment: invited talk at the 18th International Conference on Few-Body
Problems in Physics, Santos-S.Paulo, August 21-26, 200
The Desirable Organizational Structure for Evolutionary Firms in Static Landscapes
In addition to the common analysis of the Kauffman NK model where the value of K and the structure of interaction is given, the aim of this paper is to study what would be the values of these two parameters if they were endogenized. Thus, a model is proposed where firms and business schools coordinate to search for high peaks in their respective landscapes using evolutionary algorithms. The main result coming out from the analysis of the model is that agents, using evolutionary algorithms, attempt to simplify the problems of coordination and this, over time, produces the existence in the economy of agents using many different strategies. (JEL-code: C61, C63, D21, D23
On the congruence subgroup problem for branch groups
We answer a question of Bartholdi, Siegenthaler and Zalesskii, showing that
the congruence subgroup problem for branch groups is independent of the branch
action on a tree. We prove that the congruence topology of a branch group is
determined by the group; specifically, by its structure graph, an object first
introduced by Wilson. We also give a more natural definition of this graph.Comment: 9 pages, no figures; minor changes in accordance with referee report,
exposition improve
A Comparative Analysis of Self-Rectifying Turbines for the Mutriku Oscillating Water Column Energy Plant
Oscillating Water Column (OWC) based devices are arising as one of the most promising technologies for wave energy harnessing. However, the most widely used turbine comprising its power take-off (PTO) module, the Wells turbine, presents some drawbacks that require special attention. Notwithstanding different control strategies are being followed to overcome these issues; the use of other self-rectifying turbines could directly achieve this goal at the expense of some extra construction, maintenance, and operation costs. However, these newly developed turbines in turn show diverse behaviours that should be compared for each case. This paper aims to analyse this comparison for the Mutriku wave energy power plant.This work was supported by the MINECO through the
Research Project DPI2015-70075-R (MINECO/FEDER, UE)
and in part by the University of the Basque Country
(UPV/EHU) through PPG17/33. The authors would like to
thank the collaboration of the Basque Energy Agency (EVE)
through Agreement UPV/EHUEVE23/6/2011, the Spanish
National Fusion Laboratory (EURATOM-CIEMAT) through
Agreement UPV/EHUCIEMAT08/190, and EUSKAMPUSCampus
of International Excellence
Origin of three-body resonances
We expose the relation between the properties of the three-body continuum
states and their two-body subsystems. These properties refer to their bound and
virtual states and resonances, all defined as poles of the -matrix. For one
infinitely heavy core and two non-interacting light particles, the complex
energies of the three-body poles are the sum of the two two-body complex
pole-energies. These generic relations are modified by center-of-mass effects
which alone can produce a Borromean system. We show how the three-body states
evolve in He, Li, and Be when the nucleon-nucleon interaction is
continuously switched on. The schematic model is able to reproduce the main
properties in their spectra. Realistic calculations for these nuclei are shown
in detail for comparison. The implications of a core with non-zero spin are
investigated and illustrated for Ne (O+p+p). Dimensionless units
allow predictions for systems of different scales.Comment: 15 pages, 7 figure
First person – Juan Garrido-Maraver
First Person is a series of interviews with the first authors of a selection of papers published in Biology Open, helping early-career researchers promote themselves alongside their papers. Juan Garrido-Maraver is first author on 'Forcing contacts between mitochondria and the endoplasmic reticulum extends lifespan in a Drosophila model of Alzheimer's disease', published in BiO. Juan conducted the research described in this article while a postdoctoral scientist in L. Miguel Martins's lab at the MRC Toxicology Unit, University of Cambridge, Leicester, UK. He is now a postdoctoral scientist in the lab of Alvaro A. Tavares at the Centre for Biomedical Research (CBMR), University of Algarve, Faro, Portugal, investigating molecular mechanisms linked to human diseases from a therapeutic point of view.info:eu-repo/semantics/publishedVersio
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