46,411 research outputs found
Monitoring of Iberian wolf expansion in Sabugal: Malcata Region
Relatório de projecto no âmbito de Bolsa Universidade de Lisboa/Fundação Amadeu Dias (2008/2009)Departamento de Biologia Animal, Faculdade de Ciências da Universidade de LisboaScholarship Fundação Amadeu Dias/Universidade de LisboaWind farm construction may cause an effect of repulse on the wildlife. Sabugal – Malcata region has a new
wind farm in a zone where the situation of the Iberian wolf (Canis lupus signatus, Cabrera 1907) is considered as
precarious. In this context a monitoring project was begun to assess the impact of this infrastructure on the Iberian wolf
population. Here are presented the results of eight months of monitoring and some information received during the
project about the wolf presence in this region. Every month, signs of wolf presence were prospected in twelve transects
in the wind farm adjacent area and fourteen inquires were done to people that can contact with this predator. In all the
eight months only two scats were detected and two wolf tracks after a snowfall. The presence of wolves was referred in
the inquires as constant before 1990. However, some recent livestock damages were reported. The Roe deer
(Capreolus capreolus) seems to be in expansion in this area, being reported in more than half of the inquires. This
situation may reveal a new opportunity for settlement of dispersing wolves. The occurrence of the Iberian Wolf in
Sabugal – Malcata region continues not to be confirmed, but the designation of probable presence is reinforced.Universidade de Lisboa; Fundação Amadeu Dia
Structural optimisation problem in support to building retrofitting decision
Various analysis methods, either linear elastic or non-linear, static or dynamic, are available for the performance analysis of existing buildings. Despite its advantages, it must be admitted that non-linear time history analysis can frequently become overly complex and impractical for general use as a first assessment. Simplified models, as the Capacity Spectrum Method, are frequently not able to accurately assess irregular structures. Considering these limitations, it is proposed and evaluated a simplified MDOF non-linear dynamic model, accounting for non-linear storey behaviour and storey damping. Based on the MDOF non-linear dynamic model, were developed optimization algorithms for the redesign of existing non-seismically designed structures. The optimization procedure searches for the optimum storey strengthening distribution (strength, stiffness or damping) in order to meet specific performance requirements, in terms of maximum inter-storey drift for a given seismic demand level. Numerical examples are presented in order to illustrate the capability of methodology
Existence uniqueness and ratio decomposition for Gibbs states via duality
We give an elementary proof of existence and uniqueness of Gibbs states for Hölder weight systems on subshifts of finite type. This uses a notion of duality for such subshifts. The approach of Paterson [2] is used to construct a measure with a prescribed Jacobian and the duality is used to produce an invariant measure from this
Rigidity of hyperbolic sets on surfaces
Given a hyperbolic invariant set of a diffeomorphism on a surface, it is proved that, if the holonomies are sufficiently smooth, then the diffeomorphism on the hyperbolic invariant set is rigid in the sense that it is C1+ conjugate to a hyperbolic affine model
Smoothness of holonomies for codimension 1 hyperbolic dynamics
Hyperbolic invariant sets {Lambda} of C1+{gamma} diffeomorphisms where either the stable or unstable leaves are 1-dimensional are considered in this paper. Under the assumption that the {Lambda} has local product structure, the authors prove that the holonomies between the 1-dimensional leaves are C1+{alpha} for some 0 < {alpha} < 1
Quantum localized modes in capacitively coupled Josephson junctions
We consider the quantum dynamics of excitations in a system of two
capacitively coupled Josephson junctions. Quantum breather states are found in
the middle of the energy spectrum of the confined nonescaping states of the
system. They are characterized by a strong excitation of one junction. These
states perform slow tunneling motion from one junction to the other, while
keeping their coherent nature. The tunneling time sensitively depends on the
initial excitation energy. By using an external bias as a control parameter,
the tunneling time can be varied with respect to the escape time and the
experimentally limited coherence time. Thus one can control the flow of quantum
excitations between the two junctions.Comment: 5 pages, 3 figures. Improved version, title was slightly changed.
Accepted in Europhysics Letters (http://www.iop.org/EJ/journal/EPL
Quantum discrete breathers
We review recent studies about quantum discrete breathers. We describe their
basic properties in comparison with their classical counterparts, and the ways
they may be addressed theoretically in different quantum lattice models
including either bosonic or fermionic excitations. We also review recent
experimental work in the field.Comment: 49 pages, 36 figures, some corrected typos, and the section
"Conclusions and outlook" was added. Chapter for a book edited by S.
Keshavamurthy and P. Schlagheck with title "Dynamical Tunneling: Theory and
Experiment
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