13,804 research outputs found
New family of potentials with analytical twiston-like solutions
In this letter we present a new approach to find analytical twiston models.
The effective two-field model was constructed by a non-trivial combination of
two one field systems. In such an approach we successfully build analytical
models which are satisfied by a combination of two defect-like solutions, where
one is responsible to twist the molecular chain by , while the other
implies in a longitudinal movement. Such a longitudinal movement can be fitted
to have the size of the distance between adjacent molecular groups. The
procedure works nicely and can be used to describe the dynamics of several
other molecular chains.Comment: 7 pages, 3 figure
Strong-Coupling Theory for Counter-Ion Distributions
The Poisson-Boltzmann approach gives asymptotically exact counter-ion density
profiles around charged objects in the weak-coupling limit of low valency and
high temperature. In this paper we derive, using field-theoretic methods, a
theory which becomes exact in the opposite limit of strong coupling. Formally,
it corresponds to a standard virial expansion. Long-range divergences, which
render the virial expansion intractable for homogeneous bulk systems, are shown
to be renormalizable for the case of inhomogeneous distribution functions by a
systematic expansion in inverse powers of the coupling parameter. For a planar
charged wall, our analytical results compare quantitatively with extensive
Monte-Carlo simulations.Comment: 7 pages, 3 figures; to appear in Europhys. Let
Dynamical reentrance and geometry imposed quantization effects in Nb-AlOx-Nb Josephson junction arrays
In this paper, we report on different phenomena related to the magnetic
properties of artificially prepared highly ordered (periodic) two-dimensional
Josephson junction arrays (2D-JJA) of both shunted and unshunted Nb-AlOx-Nb
tunnel junctions. By employing mutual-inductance measurements and using a
high-sensitive bridge, we have thoroughly investigated (both experimentally and
theoretically) the temperature and magnetic field dependence of complex AC
susceptibility of 2D-JJA. We also demonstrate the use of the scanning SQUID
microscope for imaging the local flux distribution within our unshunted arrays
Study on the perception of DIY in domotics in Portugal
The growth of the home automation market depends on technological innovations, rapid evolution of the Internet of Things and Do-It-Yourself (DIY) solutions. This project analysed the perception about domotics related to DIY in Portugal, intending to understand if smart home technologies are used and valued, which factors motivate their acquisition, their purpose and the advantages perceived by users. A questionnaire was used to collect data, resulting in an exploratory study based on data from a convenience sample. The model to evaluate this study was based on the constructs based on Technology Acceptance Models - TAM. From the results obtained, it was concluded that the respondents have a positive perception about domotics and its usefulness faced with DIY on the technologies that make a smart home. Regarding the acquisition and installation of technologies associated with home automation on their own, the respondents are divided, as half consider that they can do it autonomously and the other half only with the intervention of specialists in home automation
Science-religion dialogue in education: religion teachers’ perceptions in a roman-catholic context
This paper examines the relationship between science and religion in the education system of Roman-Catholic Portuguese society. In particular, we explored perceptions of the relationship between science and religion for religious education teachers. We surveyed 198 Portuguese religious education teachers about how they view science and religion. The questionnaires’ results revealed a number of similarities: religious education teachers are highly involved in religious practices and exposed to science; they perceived a compatibility between science and religion; and they have an openness to dialogue between both. They do not adhere to anti-scientific perspectives, but they simultaneously try to limit what can be explained by science. Thus, an interpretative view of dialogue and/or integration seems to best explain the perceptions of religious education teachers of the relationship between science and religion. These findings allow a space of discussion, enabling teachers to possibly foster the science-religion dialogue in their contexts of pedagogical activity.info:eu-repo/semantics/acceptedVersio
Association between dietary calcium intake and blood pressure among portuguese children
[Resumo][Abstract
Semiclassical back reaction around a cosmic dislocation
The energy-momentum vacuum average of a conformally coupled massless scalar
field vibrating around a cosmic dislocation (a cosmic string with a dislocation
along its axis) is taken as source of the linearized semiclassical Einstein
equations. The solution up to first order in the Planck constant is derived.
Motion of a test particle is then discussed, showing that under certain
circumstances a helical-like dragging effect, with no classical analogue around
the cosmic dislocation, is induced by back reaction.Comment: Published version, 4 pages, no figures, REVTeX4 fil
- …