8,863 research outputs found
Theory of Andreev reflection in a two-orbital model of iron-pnictide superconductors
A recently developed theory for the problem of Andreev reflection between a
normal metal (N) and a multiband superconductor (MBS) assumes that the incident
wave from the normal metal is coherently transmitted through several bands
inside the superconductor. Such splitting of the probability amplitude into
several channels is the analogue of a quantum waveguide. Thus, the appropriate
matching conditions for the wave function at the N/MBS interface are derived
from an extension of quantum waveguide theory. Interference effects between the
transmitted waves inside the superconductor manifest themselves in the
conductance. We provide results for a FeAs superconductor, in the framework of
a recently proposed effective two-band model and two recently proposed gap
symmetries: in the sign-reversed s-wave () scenario
resonant transmission through surface Andreev bound states (ABS) at nonzero
energy is found as well as destructive interference effects that produce zeros
in the conductance; in the extended s-wave ()
scenario no ABS at finite energy are found.Comment: 4 pages, 5 figure
ADVERSE EFFECTS OF DELTAMETHRIN PESTICIDE IN OFFSPRING RATS EXPOSED IN UTERINE AND LACTATION PERIOD
Hybrid automata as coalgebras
Publicado em "Theoretical aspects of computing - ICTAC 2016: 13th International Colloquium, Taipei, Taiwan, ROC, October 24–31, 2016, Proceedings". ISBN 978-3-319-46749-8Able to simultaneously encode discrete transitions and continuous
behaviour, hybrid automata are the de facto framework for the
formal specification and analysis of hybrid systems. The current paper
revisits hybrid automata from a coalgebraic point of view. This allows to
interpret them as state-based components, and provides a uniform theory
to address variability in their definition, as well as the corresponding
notions of behaviour, bisimulation, and observational semantics.FCT grants SFRH/BD/52234/2013, SFRH/BSAB/ 113890/2015ERDF - European Regional Development Fund, through the COMPETE Programme, and by National Funds through FCT within project PTDC/EEI-CTP/4836/201
Screening effects in flow through rough channels
A surprising similarity is found between the distribution of hydrodynamic
stress on the wall of an irregular channel and the distribution of flux from a
purely Laplacian field on the same geometry. This finding is a direct outcome
from numerical simulations of the Navier-Stokes equations for flow at low
Reynolds numbers in two-dimensional channels with rough walls presenting either
deterministic or random self-similar geometries. For high Reynolds numbers,
when inertial effects become relevant, the distribution of wall stresses on
deterministic and random fractal rough channels becomes substantially dependent
on the microscopic details of the walls geometry. In addition, we find that,
while the permeability of the random channel follows the usual decrease with
Reynolds, our results indicate an unexpected permeability increase for the
deterministic case, i.e., ``the rougher the better''. We show that this complex
behavior is closely related with the presence and relative intensity of
recirculation zones in the reentrant regions of the rough channel.Comment: 4 pages, 5 figure
Languages and models for hybrid automata: A coalgebraic perspective
article in pressWe study hybrid automata from a coalgebraic point of view. We show that such a perspective supports a generic theory of hybrid automata with a rich palette of definitions and results. This includes, among other things, notions of bisimulation and behaviour, state minimisation techniques, and regular expression languages.POCI-01-0145-FEDER-016692. RDF — European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation — COMPETE 2020 Programme and by National Funds through the Portuguese funding agency, FCT — Fundação para a Ciência e a Tecnologia within project POCI-01-0145-FEDER-016692 and by the PT-FLAD Chair on Smart Cities & Smart Governance at Universidade do Minh
Comportamento de genótipos de mamoeiro Carica papaya, L. em relação à Phytophthora palmivora Butler sob diferentes tipos de solos e lâminas d?água.
O presente trabalho consiste em avaliar o comportamento de sete genótipos de mamoeiro (CMF 060, Sunrise Solo, L06-08, L72-08, L47-P5, L47-P8 e Calimosa) ante a presença de Phytophthora palmivora Butler e identificar fontes de resistência presentes em acessos do Banco Ativo de Germoplasma (BAG-Mamão) da Embrapa Mandioca e Fruticultura. A avaliação foi realizada em mudas envasadas mantidas em câmara de crescimento, inoculadas com uma suspensão do patógeno em três tipos de solo (argiloso, franco argiloso e arenoso) e duas lâminas d?água, uma a 100% e outra a 60% da capacidade de campo
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