12,159 research outputs found
Cosmic magnetic fields and dark energy in extended electromagnetism
We discuss an extended version of electromagnetism in which the usual gauge
fixing term is promoted into a physical contribution that introduces a new
scalar state in the theory. This new state can be generated from vacuum quantum
fluctuations during an inflationary era and, on super-Hubble scales, gives rise
to an effective cosmological constant. The value of such a cosmological
constant coincides with the one inferred from observations as long as inflation
took place at the electroweak scale. On the other hand, the new state also
generates an effective electric charge density on sub-Hubble scales that
produces both vorticity and magnetic fields with coherent lengths as large as
the present Hubble horizon.Comment: 4 pages, 2 figures. Contribution to the proceedings of Spanish
Relativity Meeting 2010, Granada, Spain, 6-10 September 201
Low-dimensional dynamics embedded in a plane Poiseuille flow turbulence : Traveling-wave solution is a saddle point ?
The instability of a streak and its nonlinear evolution are investigated by
direct numerical simulation (DNS) for plane Poiseuille flow at Re=3000. It is
suggested that there exists a traveling-wave solution (TWS). The TWS is
localized around one of the two walls and notably resemble to the coherent
structures observed in experiments and DNS so far. The phase space structure
around this TWS is similar to a saddle point. Since the stable manifold of this
TWS is extended close to the quasi two dimensional (Q2D) energy axis, the
approaching process toward the TWS along the stable manifold is approximately
described as the instability of the streak (Q2D flow) and the succeeding
nonlinear evolution. Bursting corresponds to the escape from the TWS along the
unstable manifold. These manifolds constitute part of basin boundary of the
turbulent state.Comment: 5 pages, 6 figure
Background and approach to a definition of smart buildings
There is no possibility of finding a single reference about domotics in the first half of the 20th century. The best known authors and those who have documented this discipline, set its origin in the 1970’s, when the x-10 technology began to be used, but it was not until 1988 when Larousse Encyclopedia decided to include the definition of "Smart Building". Furthermore, even nowadays, there is not a single definition widely accepted, and for that reason, many other expressions, namely "Intelligent Buildings" "Domotics" "Digital Home" or "Home Automation" have appeared to describe the automated buildings and homes. The lack of a clear definition for "Smart Buildings" causes difficulty not only in the development of a common international framework to develop research in this field, but it also causes insecurity in the potential user of these buildings. Thus, the main purpose of this paper is to propose a definition of the expression “Smart Buildings” that satisfactorily describes the meaning of this discipline. To achieve this aim, a thorough review of the origin of the term itself and the historical background before the emergence of the phenomenon of domotics was conducted, followed by a critical discussion of existing definitions of the term "Smart Buildings" and other similar terms. The extent of each definition has been analyzed, inaccuracies have been discarded and commonalities have been compared. Throughout the discussion, definitions that bring the term "Smart Buildings" near to disciplines such as computer science, robotics and also telecommunications have been found
The magnetic precursor of L1448-mm: Excitation differences between ion and neutral fluids
Shock modelling predicts an electron density enhancement within the magnetic
precursor of C-shocks. Previous observations of SiO, H13CO+, HN13C and H13CN
toward the young L1448-mm outflow showed an over-excitation of the ion fluid
that was attributed to an electron density enhancement in the precursor. We
re-visit this interpretation and test if it still holds when we consider
different source morphologies and kinetic temperatures for the observed
molecules, and also give some insight on the spatial extent of the electron
density enhancement around L1448-mm.
We estimate the opacities of H13CO+ and HN13C by observing the J=3\to2 lines
of rarer isotopologues to confirm that the emission is optically thin. To model
the excitation of the molecules, we use the large velocity gradient (LVG)
approximation with updated collisional coefficients to i) re- analyse the
observations toward the positions where the over-excitation of H13CO+ has
previously been observed [i.e. toward L1448- mm at offsets (0,0) and (0,-10)],
and ii) to investigate if the electron density enhancement is still required
for the cases of extended and compact emission, and for kinetic temperatures of
up to 400 K. We also report several lines of SiO, HN13C and H13CO+ toward new
positions around this outflow, to investigate the spatial extent of the
over-excitation of the ions in L1448-mm. From the isotopologue observations, we
find that the emission of H13CO+ and HN13C from the precursor is optically thin
if this emission is extended. Using the new collisional coefficients, an
electron density enhancement is still needed to explain the excitation of
H13CO+ for extended emission and for gas temperatures of\le 400 K toward
L1448-mm (0,-10), and possibly also toward L1448-mm (0,0). For compact emission
the data cannot be fitted. We do not find any evidence for the over-excitation
of the ion fluid toward the newly observed positions around L1448-mm.
The observed line emission of SiO, H13CO+ and HN13C toward L1448-mm (0,0) and
(0,-10) is consistent with an electron density enhancement in the precursor
component, if this emission is spatially extended. This is also true for the
case of high gas temperatures (\le400 K) toward the (0,-10) offset. The
electron density enhancement seems to be restricted to the southern, redshifted
lobe of the L1448-mm outflow. Interferometric images of the line emission of
these molecules are needed to confirm the spatial extent of the over-excitation
of the ions and thus, of the electron density enhancement in the magnetic
precursor of L1448-mm.Comment: Accepted for publication in A&A; 9 pages, 3 figure
Gamificacion con estrategia de marketing interno
Purpose: Theoretical analysis of the phenomenon of gamification and its possible application as a tool for internal marketing, in order to increase job satisfaction and commitment through engagement.
Design/methodology/approach: Firstly, review of the literature on gamification and its background within game social reality. Secondly, presentation of several business cases where gamification has been applied.
Findings: Focusing the subject of gamification within the field of internal marketing. In addition, a theoretical model of gamification as a tool to improve some consequences on employees’ behavior, such as job satisfaction and commitment through engagement, is proposed,. Various specific hypotheses for future research are proposed based on this model..
Practical implications: Because of the situation of research on internal marketing and gamification, practical implications cannot be deduced in the short term, although they may arise as long as there is empirical evidence of its usefulness.
Social implications: Currently there is no empirical evidence to infer social implications.
Originality/value: Gamification is a very recent phenomenon that has been scarcely studied
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