419 research outputs found
Influencia de la alimentación del cerdo ibérico en las características de los compuestos relacionados con la grasa del jamón curado
Alimentation influence (acorn, acorn-bait mixed, bait) over characteristics fat and their degradation products, that are in part, responsible of the aroma of ham, has been studied. Influence over the naturation degree has been observed. Relation oleic/linoleic+linolenic acids are different In the three types of hams. Also water activity, salinity index and redox potential show differences that affect to the relative percentage of satured and unsatured free fatty acids. Fat of bait hams suffer more oxidation. Acorn and mixed acornbait hams offer a higher level of pentanal and acetaldehyde. Whereas bait hams have higher level of hexanal, heptanal and octanal. The percentage of cetonic compounds are similar in all then.Se ha estudiado la influencia que pueda tener la alimentación del cerdo ibérico (bellota, recebo, pienso) sobre las características de la grasa y sus productos de degradación, responsables en parte del aroma que presenta el jamón curado. Se ha puesto de manifiesto una incidencia de la alimentación sobre la insaturación de la grasa intramuscular del jamón, que se refleja en la relación parcial, que en cada tipo de jamón aparece entre el ácido oleico y la suma de linoleico y linolénico. Diferencias en parámetros de curación como actividad de agua, índice de salinidad y potencial redox, tienen su reflejo en las diferencias encontradas para las proporciones relativas entre los ácidos grasos libres saturados e insaturados. Una mayor oxidación en la grasa de jamones de pienso marca también diferencias con los otros tipos de jamones en lo que respecta a sus componentes volátiles.
Los jamones de bellota y recebo son más ricos en los aldehídos acetaldehído y pentanal, mientras que los jamones de pienso tienen mayor contenido en hexanal, heptanal y octanal. Los tres tipos de jamones coinciden en los porcentajes de los componentes cetónicos: propanona, 2-butanona y 2-pentanona
Shortcuts in a Nonlinear Dynamical Braneworld in Six Dimensions
We consider a dynamical brane world in a six-dimensional spacetime containing
a singularity. Using the Israel conditions we study the motion of a 4-brane
embedded in this setup. We analyse the brane behaviour when its position is
perturbed about a fixed point and solve the full nonlinear dynamics in the
several possible scenarios. We also investigate the possible gravitational
shortcuts and calculate the delay between graviton and photon signals and the
ratio of the corresponding subtended horizons.Comment: 26 pages, 9 figures. References and discussion added. Title changed
to match the version accepted in Class. and Quant. Gra
Perturbations of Gauss-Bonnet Black Strings in Codimension-2 Braneworlds
We derive the Lichnerowicz equation in the presence of the Gauss-Bonnet term.
Using the modified Lichnerowicz equation we study the metric perturbations of
Gauss-Bonnet black strings in Codimension-2 Braneworlds.Comment: 26 pages, no figures, clarifying comments and one reference added, to
be published in JHE
Photonically-driven Schottky diode based 0.3 THz heterodyne receiver
Photonics-based technologies are key players in a number of emerging applications in the terahertz (THz) field. These solutions exploit the well-known advantages of optical devices, such as ultra-wide tuneability and direct integration with fiber networks. However, THz receivers are mainly implemented by fully electronic solutions, where Schottky barrier diodes (SBD) are the preferred option as detectors and mixers due to their excellent response within the THz range at room temperature, and technological maturity. Here, we demonstrate an SBD-based subharmonic mixer (SHM) at 300 GHz pumped with a photonic local oscillator. The Schottky mixer is a prototype designed and manufactured by ACST GmbH, operating at 270-320 GHz. The local oscillator is generated by photomixing on a high-frequency and high-power uni-travelling-carrier photodiode (UTC-PD), providing enough power to saturate conversion loss. Minimum single-side-band conversion loss of 14.4 dB and a peak dynamic range of 130 dB have been measured. Finally, as a proof of concept we realize an all-photonics-based 5 Gbps wireless bridge, utilizing the optically-pumped SBD mixer. With this work, we prove the feasibility of high-performance hybrid Schottky-photonic THz receivers, incorporating the best of both worlds
Influencia de la alimentación del cerdo ibérico en las características de los compuestos relacionados con la grasa del jamón curado
Influencia de la alimentación del cerdo ibérico en las características
de los compuestos relacionados con la grasa del jamón
curado.
Se ha estudiado la influencia que pueda tener la alimentación
del cerdo ibérico (bellota, recebo, pienso) sobre las características
de la grasa y sus productos de degradación, responsables en parte
del aroma que presenta el jamón curado. Se ha puesto de manifiesto
una incidencia de la alimentación sobre la insaturación de la grasa
intramuscular del jamón, que se refleja en la relación parcial, que en
cada tipo de jamón aparece entre el ácido oleico y la suma de linoleico
y linolénico. Diferencias en parámetros de curación como actividad
de agua, índice de salinidad y potencial redox, tienen su reflejo en
las diferencias encontradas para las proporciones relativas entre los
ácidos grasos libres saturados e insaturados. Una mayor oxidación
en la grasa de jamones de pienso marca también diferencias con los
otros tipos de jamones en lo que respecta a sus componentes volátiles.
Los jamones de bellota y recebo son más ricos en los aldehidos
acetaldehido y pentanal, mientras que los jamones de pienso tienen
mayor contenido en hexanal, heptanal y octanal. Los tres tipos de
jamones coinciden en los porcentajes de los componentes cetónicos:
propanona, 2-butanona y 2-pentanona.Alimentation Influence in the characteristics of compounds
related with fat of ham from iberic pigs.
Alimentation influence (acorn, acorn-bait mixed, bait) over characteristics
fat and their degradation products, that are in part,
responsible of the aroma of ham, has been studied. Influence over
the naturation degree has been observed. Relation oleic/
linoleic+linolenic acids are different In the three types of hams. Also
water activity, salinity index and redox potential show differences that
affect to the relative percentage of satured and unsatured free fatty
acids. Fat of bait hams suffer more oxidation. Acorn and mixed acornbait
hams offer a higher level of pentanal and acetaldehyde. Whereas
bait hams have higher level of hexanal, heptanal and octanal. The
percentage of cetonic compounds are similar in all then
Instability of brane cosmological solutions with flux compactifications
We discuss the stability of the higher-dimensional de Sitter (dS) brane
solutions with two-dimensional internal space in the Einstein-Maxwel theory. We
show that an instability appears in the scalar-type perturbations with respect
to the dS spacetime. We derive a differential relation which has the very
similar structure to the ordinary laws of thermodynamics as an extension of the
work for the six-dimensional model [20]. In this relation, the area of dS
horizon (integrated over the two internal dimensions) exactly behaves as the
thermodynamical entropy. The dynamically unstable solutions are in the
thermodynamically unstable branch. An unstable dS compactification either
evolves toward a stable configuration or two-dimensional internal space is
decompactified. These dS brane solutions are equivalent to the accelerating
cosmological solutions in the six-dimensional Einstein-Maxwell-dilaton theory
via dimensional reduction. Thus, if the seed higher-dimensional solution is
unstable, the corresponding six-dimensional solution is also unstable. From the
effective four-dimensional point of view, a cosmological evolution from an
unstable cosmological solution in higher dimensions may be seen as a process of
the transition from the initial cosmological inflation to the current dark
energy dominated Universe.Comment: 11 pages, 3 figures, references added, to appear in CQ
The shortest cut in brane cosmology
We consider brane cosmology studying the shortest null path on the brane for
photons, and in the bulk for gravitons. We derive the differential equation for
the shortest path in the bulk for a 1+4 cosmological metric. The time cost and
the redshifts for photons and gravitons after traveling their respective path
are compared. We consider some numerical solutions of the shortest path
equation, and show that there is no shortest path in the bulk for the
Randall-Sundrum vacuum brane solution, the linear cosmological solution of
Bin\'etruy, et al for , and for some expanding brane
universes.Comment: 20 pages, 7 figure
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