30,317 research outputs found
The Influence of oral environment on diet choices in goats: a focus on saliva protein composition
There is ample evidence that ruminants are capable of making choices between
different foods that provide a more balanced diet that would be obtained by eating at
random. In the particular case of goats, they occupy a diversity of habitats and different
breeds present variability of feeding behaviors resultant from adaptations to the existent
plant species. In their food search activity, individuals are faced with variable amounts of
plant secondary metabolites (PSMs), which may present some toxic and anti-nutritional
effects depending on the individual’s ability to deal with it.
The oral cavity has a key role in the recognition and decision processes of ingestion
or rejection. In this chapter we will first consider how goats identify foods and behave
according to the food items available. Focus will be done on the importance of taste sense
in this process and the information available on the main structures involved in taste
detection and perception in goats will be reviewed. In a second section we will focus on
the characteristics of goat’s saliva, particularly in terms of their protein composition,
presenting results obtained by our research team
On the -Dirac Oscillator revisited
This Letter is based on the -Dirac equation, derived from the
-Poincar\'{e}-Hopf algebra. It is shown that the -Dirac
equation preserves parity while breaks charge conjugation and time reversal
symmetries. Introducing the Dirac oscillator prescription,
, in the -Dirac
equation, one obtains the -Dirac oscillator. Using a decomposition in
terms of spin angular functions, one achieves the deformed radial equations,
with the associated deformed energy eigenvalues and eigenfunctions. The
deformation parameter breaks the infinite degeneracy of the Dirac oscillator.
In the case where , one recovers the energy eigenvalues and
eigenfunctions of the Dirac oscillator.Comment: 5 pages, no figures, accepted for publication in Physics Letters
Modelling of epitaxial film growth with a Ehrlich-Schwoebel barrier dependent on the step height
The formation of mounded surfaces in epitaxial growth is attributed to the
presence of barriers against interlayer diffusion in the terrace edges, known
as Ehrlich-Schwoebel (ES) barriers. We investigate a model for epitaxial growth
using a ES barrier explicitly dependent on the step height. Our model has an
intrinsic topological step barrier even in the absence of an explicit ES
barrier. We show that mounded morphologies can be obtained even for a small
barrier while a self-affine growth, consistent with the Villain-Lai-Das Sarma
equation, is observed in absence of an explicit step barrier. The mounded
surfaces are described by a super-roughness dynamical scaling characterized by
locally smooth (faceted) surfaces and a global roughness exponent .
The thin film limit is featured by surfaces with self-assembled
three-dimensional structures having an aspect ratio (height/width) that may
increase or decrease with temperature depending on the strength of step
barrier.Comment: To appear in J. Phys. Cond. Matter; 3 movies as supplementary
materia
Kinetic modelling of epitaxial film growth with up- and downward step barriers
The formation of three-dimensional structures during the epitaxial growth of
films is associated to the reflection of diffusing particles in descending
terraces due to the presence of the so-called Ehrlich-Schwoebel (ES) barrier.
We generalize this concept in a solid-on-solid growth model, in which a barrier
dependent on the particle coordination (number of lateral bonds) exists
whenever the particle performs an interlayer diffusion. The rules do not
distinguish explicitly if the particle is executing a descending or an
ascending interlayer diffusion. We show that the usual model, with a step
barrier in descending steps, produces spurious, columnar, and highly unstable
morphologies if the growth temperature is varied in a usual range of mound
formation experiments. Our model generates well-behaved mounded morphologies
for the same ES barriers that produce anomalous morphologies in the standard
model. Moreover, mounds are also obtained when the step barrier has an equal
value for all particles independently if they are free or bonded. Kinetic
roughening is observed at long times, when the surface roughness w and the
characteristic length scale as and where
and , independently of the growth
temperature.Comment: 15 pages, 7 figure
Probing wrong-sign Yukawa couplings at the LHC and a future linear collider
We consider the two-Higgs-doublet model as a framework in which to evaluate
the viability of scenarios in which the sign of the coupling of the observed
Higgs boson to down-type fermions (in particular, -quark pairs) is opposite
to that of the Standard Model (SM), while at the same time all other tree-level
couplings are close to the SM values. We show that, whereas such a scenario is
consistent with current LHC observations, both future running at the LHC and a
future linear collider could determine the sign of the Higgs coupling
to -quark pairs. Discrimination is possible for two reasons. First, the
interference between the -quark and the -quark loop contributions to the
coupling changes sign. Second, the charged-Higgs loop contribution to the
coupling is large and fairly constant up to the largest
charged-Higgs mass allowed by tree-level unitarity bounds when the -quark
Yukawa coupling has the opposite sign from that of the SM (the change in sign
of the interference terms between the -quark loop and the and loops
having negligible impact).Comment: 28 pages, 21 figure
Magnetic particles confined in a modulated channel: structural transitions tunable by tilting a magnetic field
The ground state of colloidal magnetic particles in a modulated channel are
investigated as function of the tilt angle of an applied magnetic field. The
particles are confined by a parabolic potential in the transversal direction
while in the axial direction a periodic substrate potential is present. By
using Monte Carlo (MC) simulations, we construct a phase diagram for the
different crystal structures as a function of the magnetic field orientation,
strength of the modulated potential and the commensurability factor of the
system. Interestingly, we found first and second order phase transitions
between different crystal structures, which can be manipulated by the
orientation of the external magnetic field. A re-entrant behavior is found
between two- and four-chain configurations, with continuous second order
transitions. Novel configurations are found consisting of frozen in solitons.
By changing the orientation and/or strength of the magnetic field and/or the
strength and the spatial frequency of the periodic substrate potential, the
system transits through different phases.Comment: Submitted to Phys. Rev. E (10 pages, 12 figures
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