10,144 research outputs found
CHEMICAL AND PHYSICAL CHARACTERISTICS OF M. PSOAS MAIOR FROM ALENTEJANO PIGS AT A VARIOUS LIVE WEIGTHS
The present study was carried out to investigate the evolution of biochemical composition and physical traits of the chemical composition and physical characteristics of muscle Psoas major (PM adipose during growth of Alentejano pigs
Minimally Extended Left-Right Symmetric Model for Dark Matter with U(1) Portal
A minimal extension of the left-right symmetric model for neutrino masses
that includes a vector-like singlet fermion dark matter (DM) is presented with
the DM connected to the visible sector via a gauged U(1) portal. We discuss the
symmetry breaking in this model and calculate the mass and mixings of the extra
heavy neutral gauge boson at the TeV scale. The extra gauge boson can decay to
both standard model particles as well to dark matter. We calculate the relic
density of the singlet fermion dark matter and its direct detection cross
section and use these constraints to obtain the allowed parameter range for the
new gauge coupling and the dark matter mass.Comment: 19 pages, 8 figure
A 3-form Gauge Potential in 5D in connection with a Possible Dark Sector of 4D-Electrodynamics
We here propose a 5-dimensional {\bf Abelian gauge} model based on the mixing
between a potential and an Abelian 3-form field by means of a
topological mass term. An extended covariant derivative is introduced to
minimally couple a Dirac field to the potential, while this same
covariant derivative non-minimally couples the 3-form field to the charged
fermion. A number of properties are discussed in 5D; in particular, the
appearance of a topological fermionic current. A 4-dimensional reduced version
of the model is investigated and, { \bf in addition to the electric- and
magnetic-sort of fields,} there emerges an extra set of electric- and
magnetic-like fields which contribute a negative pressure and may be identified
as a possible fraction of dark energy. The role of the topological fermionic
current is also contemplated upon dimensional reduction from 5D to 4D. Other
issues we present in 4 space-time dimensions are the emergence {\bf of a
pseudo-scalar massive particle,} an extra massive neutral gauge boson,{\bf
which we interpret as a kind of paraphoton}, and the calculation of spin- and
velocity-dependent interparticle potentials associated to the exchange of the
intermediate bosonic fields of the model.Comment: -- 30 pages -- L. P. R. Ospedal appears as a new co-author;
modifications by inclusion of the gravitational sector and the attainment of
a spin- and velocity-dependent potential as an application have been worked
out in this Revised Versio
Hamiltonian symplectic embedding of the massive noncommutative U(1) Theory
We show that the massive noncommutative U(1) theory is embedded in a gauge
theory using an alternative systematic way, which is based on the symplectic
framework. The embedded Hamiltonian density is obtained after a finite number
of steps in the iterative symplectic process, oppositely to the result proposed
using the BFFT formalism. This alternative formalism of embedding shows how to
get a set of dynamically equivalent embedded Hamiltonian densities.Comment: 16 pages, no figures, revtex4, corrected version, references
additione
Evaluation of the stiffness modulus of bituminous mixtures using laboratory tests (NAT) validate by field back-analysis
This paper concerns the evaluation of the stiffness modulus of bituminous
mixtures by using the Nottingham Asphalt Tester (NAT). On the basis of indirect tensile
laboratory test results, a practical model for stiffness modulus prediction in pavement bearing
capacity analysis was established and calibrated for some typical bituminous mixtures used in
Portuguese asphalt pavements. Validation of this model was based on two experimental fullscale
pavements instrumented du ring construction. To study the bearing capacity of the
pavement structure, wheel load tests were carried out with simultaneous instruments
measurements. Experimental pavements response modelling during load tests was performed
using the finite elements method. The reasonably agreements between the calculated and
measured strains indicate that the stiffness modulus prediction method is greatly reliable for
the bituminous mixtures tested and could be very useful for further bearing capacity design of
asphalt pavements
Optimized generation of spatial qudits by using a pure phase spatial light modulator
We present a method for preparing arbitrary pure states of spatial qudits,
namely, D-dimensional (D > 2) quantum systems carrying information in the
transverse momentum and position of single photons. For this purpose, a set of
D slits with complex transmission are displayed on a spatial light modulator
(SLM). In a recent work we have shown a method that requires a single
phase-only SLM to control independently the complex coefficients which define
the quantum state of dimension D. The amplitude information was codified by
introducing phase gratings inside each slit and the phase value of the complex
transmission was added to the phase gratings. After a spatial filtering process
we obtained in the image plane the desired qudit state. Although this method
has proven to be a good alternative to compact the previously reported
architectures, it presents some features that could be improved. In this paper
we present an alternative scheme to codify the required phase values that
minimizes the effects of temporal phase fluctuations associated to the SLM
where the codification is carried on. In this scheme the amplitudes are set by
appropriate phase gratings addressed at the SLM while the relative phases are
obtained by a lateral displacement of these phase gratings. We show that this
method improves the quality of the prepared state and provides very high
fidelities of preparation for any state. An additional advantage of this scheme
is that a complete 2\pi modulation is obtained by shifting the grating by one
period, and hence the encoding is not limited by the phase modulation range
achieved by the SLM. Numerical simulations, that take into account the phase
fluctuations, show high fidelities for thousands of qubit states covering the
whole Bloch sphere surface. Similar analysis are performed for qudits with D =
3 and D = 7.Comment: 12 pages, 7 figure
Order and Disorder in AKLT Antiferromagnets in Three Dimensions
The models constructed by Affleck, Kennedy, Lieb, and Tasaki describe a
family of quantum antiferromagnets on arbitrary lattices, where the local spin
S is an integer multiple M of half the lattice coordination number. The equal
time quantum correlations in their ground states may be computed as finite
temperature correlations of a classical O(3) model on the same lattice, where
the temperature is given by T=1/M. In dimensions d=1 and d=2 this mapping
implies that all AKLT states are quantum disordered. We consider AKLT states in
d=3 where the nature of the AKLT states is now a question of detail depending
upon the choice of lattice and spin; for sufficiently large S some form of Neel
order is almost inevitable. On the unfrustrated cubic lattice, we find that all
AKLT states are ordered while for the unfrustrated diamond lattice the minimal
S=2 state is disordered while all other states are ordered. On the frustrated
pyrochlore lattice, we find (conservatively) that several states starting with
the minimal S=3 state are disordered. The disordered AKLT models we report here
are a significant addition to the catalog of magnetic Hamiltonians in d=3 with
ground states known to lack order on account of strong quantum fluctuations.Comment: 7 pages, 2 figure
- …