1,901 research outputs found
A Matter of Taste: Capsaicinoid Diversity in Chile Peppers and the Importance to Human Food Preference
Chile peppers are valued worldwide for their distinct capsaicinoid compounds that have been used traditionally in medicine and culinary practices. With 32 known species, five of them domesticated, they provide unique chemical profiles, when consumed by humans. Capsaicinoids, the spicy compounds, are alkaloids used to deter herbivory in the wild, offering protection to the chile pepper fruit seeds. Among the 22 known capsaicinoid structures, capsaicin and dihydrocapsaicin are normally the most abundant. In humans, capsaicin binds to nociceptor TRPV1 that generates a heat sensation. Capsaicin also mitigates inflammation responses in the digestive tract and has the potential to aid in nutrient absorption. Distinct heat profiles were recently described for the five domesticated Capsicum species showing a difference in heat sensations specific to species and pod type. Due to the many capsaicinoid structures, we explore the implications and opportunities of having a diverse array of heat profiles in genetically diverse Capsicum species
Spherical Hartree-Fock calculations with linear momentum projection before the variation.Part II: Spectral functions and spectroscopic factors
The hole--spectral functions and from these the spectroscopic factors have
been calculated in an Galilei--invariant way for the ground state wave
functions resulting from spherical Hartree--Fock calculations with projection
onto zero total linear momentum before the variation for the nuclei 4He, 12C,
16O, 28Si, 32S and 40Ca. The results are compared to those of the conventional
approach which uses the ground states resulting from usual spherical
Hartree--Fock calculations subtracting the kinetic energy of the center of mass
motion before the variation and to the results obtained analytically with
oscillator occupations.Comment: 16 pages, 22 postscript figure
Casimir torque
We develop a formalism for the calculation of the flow of angular momentum
carried by the fluctuating electromagnetic field within a cavity bounded by two
flat anisotropic materials. By generalizing a procedure employed recently for
the calculation of the Casimir force between arbitrary materials, we obtain an
expression for the torque between anisotropic plates in terms of their
reflection amplitude matrices. We evaluate the torque in 1D for ideal and
realistic model materials.Comment: 8 pages, 4 figs, Submitted to Proc. of QFEXT'05, to appear in J.
Phys.
Role of triaxiality in the ground state shape of neutron rich Yb, Hf, W, Os, and Pt isotopes
The evolution of the ground-state shape along the triaxial landscape of
several isotopes of Yb, Hf, W, Os, and Pt is analyzed using the self-consistent
Hartree-Fock-Bogoliubov approximation. Two well reputed interactions (Gogny D1S
and Skyrme SLy4) have been used in the study in order to asses to which extent
the results are independent of the details of the effective interaction. A
large number of even-even nuclei, with neutron numbers from N=110 up to N=122
has been considered, covering in this way a vast extension of the nuclear
landscape where signatures of oblate-prolate shape transitions have already
manifested both theoretically and experimentally.Comment: 21 pages, 8 figure
Time-dependent Mechanics and Lagrangian submanifolds of Dirac manifolds
A description of time-dependent Mechanics in terms of Lagrangian submanifolds
of Dirac manifolds (in particular, presymplectic and Poisson manifolds) is
presented. Two new Tulczyjew triples are discussed. The first one is adapted to
the restricted Hamiltonian formalism and the second one is adapted to the
extended Hamiltonian formalism
Noncommutivity and Scalar Field Cosmology
In this work we extend and apply a previous proposal to study noncommutative
cosmology to the FRW cosmological background coupled to a scalar field, this is
done in classical and quantum scenarios. In both cases noncommutativity is
introduced in the gravitational field as well as in the scalar field through a
deformation of minisuperspace and are able to find exact solutions. Finally,
the effects of noncommutativity on the classical evolution are analyzed.Comment: 4 Pages, 2 figures, Revtex
Water, land and carbon footprints of Chinese dairy in the past and future
Chinese food consumption shifts towards larger milk consumption. Traditional dairy systems depended on China's grasslands, but modern industrial systems using feed from croplands increase rapidly. The question is whether China can fulfill future milk demand using its natural resources and remain within greenhouse gas emission boundaries. To determine this, this study combines three footprint analyses - water footprint (WF), land footprint (LF) and carbon footprint (CF) - estimated via production chain approach. It compares WFs, LFs and CFs of milk, meat, and manure from six dairy systems in three categories: traditional grazing, traditional mixed, and modern industrial systems. It estimates future footprints for five production scenarios for low and high milk demand. Between 2000 and 2020, industrial systems increased, accounting for 79 % of production in 2020, while traditional production decreased. Traditional grazing systems have large green WFs per kg (17.2 m3), negligible blue WFs and large LFs (46 m2 low quality grassland). Traditional mixed systems have large CFs per kg (2.93 kg CO2) due to low efficiency. Modern industrial systems rely partly on irrigated croplands and have small green WFs, but large blue WFs per kg (0.54 m3), grey WFs (0.24 m3) and small LFs (1.80 m2 cropland). The findings indicate that with dominating industrial systems, milk production relies more on irrigation and limited croplands. In a realistic low demand situation, milk consumption stabilizes. However, consumption triples if the Chinese follow nutritional advice, resulting in 4 to 6 times larger WFs, LFs and CFs in 2035 depending on production scenarios. In 2035, population is largest, from 2035 to 2050 footprints decrease again. However, China cannot produce the milk for a high consumption situation limited by grassland and cropland availability. Alternatively, China could import feed or milk. However, it is questionable whether these huge quantities are available on the global market.</p
Accretion of phantom scalar field into a black hole
Using numerical methods we present the first full nonlinear study of phantom
scalar field accreted into a black hole. We study different initial
configurations and find that the accretion of the field into the black hole can
reduce its area down to 50 percent within time scales of the order of few
masses of the initial horizon. The analysis includes the cases where the total
energy of the space-time is positive or negative. The confirmation of this
effect in full nonlinear general relativity implies that the accretion of
exotic matter could be considered an evaporation process. We speculate that if
this sort of exotic matter has some cosmological significance, this black hole
area reduction process might have played a crucial role in black hole formation
and population.Comment: 5 revtex pages, 4 eps figures. Minor changes applie
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