1,556 research outputs found
Tanino condensando das espécies jurema preta (Mimosa hostilis), sabiá (Mimosa caesalpinifolia) e mororó (Bauhinia cheilantha), em três fases do ciclo fenológico.
Resumo: O objetivo do presente trabalho foi caracterizar os taninos condensados das espécies Jurema Preta (Mimosa hostilis), Sabiá (Mimosa caesalpinifolia) e Mororó (Bauhinia cheilantha) nas fases de vegetação(Mimosa hostilis), Sabiá (Mimosa caesalpinifolia) e Mororó (Bauhinia cheilantha) nas fases de vegetação plena, floração plena e frutificação. A concentração em tanino solúvel, tanino ligado ao resíduo e tanino total (TT) foi determinada pelo método butanol-HCL e a adstringência pelo método de difusão radial. Foram observadas diferenças entre as espécies quanto a concentração (P<0,05) e adstringência (P<0,05) dos taninos. A Jurema Preta apresentou os maiores valores (30,98% TT e 22% de adstringência na vegetação plena) e Mororó as menores (10,38% TT e 14% de adstringência na frutificação). A concentração e adstringência dos taninos condensados, assim como a adstringência variaram entre as espécies e, em alguns casos, entre as fases do ciclo fenológico. Os valores observados foram sempre superiores aos considerados benéficos (5%) para a digestão ruminal e aproveitamento geral da dieta. Abstract: This study was conducted aiming at characterizing the condensed tannins present in the legumes species Jurema Preta (Mimosa hostilis), Sabiá (Mimosa caesalpinifolia) and Mororó (Bauhinia cheilantha) at three stages of their phenological cycle. The concentration of soluble tannin, bound tannin and total tannin (TT) was determined using the butanol-HCL method and astringency was determined using the radial diffusion method. Jurema Preta presented the highest values (30.98% TT and 22 % astringency at full growth stage), and Mororó the lowest (10.38% TT and 14 % astringency during fructification). Concentration and astringency of condensed tannins, as well as their monomeric composition varied between species, and in some cases among phenological cycles. The values observed were always above the limits considered beneficial for ruminal digestion (i.e. 5%)
Good Applications for Crummy Entity Linkers? The Case of Corpus Selection in Digital Humanities
Influência dos taninos condensados sobre a degradabilidade ruminal de jurema preta (Mimosa hostilis), sabiá (Mimosa caesalpinifolia) e mororó (Bauhinia cheilantha).
Detection of chloronium and measurement of the 35Cl/37Cl isotopic ratio at z=0.89 toward PKS1830-211
We report the first extragalactic detection of chloronium (H2Cl+), in the
z=0.89 absorber in front of the lensed blazar PKS1830-211. The ion is detected
through its 1_11-0_00 line along two independent lines of sight toward the
North-East and South-West images of the blazar. The relative abundance of H2Cl+
is significantly higher (by a factor ~7) in the NE line of sight, which has a
lower H2/H fraction, indicating that H2Cl+ preferably traces the diffuse gas
component. From the ratio of the H2^35Cl+ and H2^37Cl+ absorptions toward the
SW image, we measure a 35Cl/37Cl isotopic ratio of 3.1 (-0.2; +0.3) at z=0.89,
similar to that observed in the Galaxy and the solar system.Comment: Accepted for publication in A&A Lette
Probing the jet base of the blazar PKS1830-211 from the chromatic variability of its lensed images. Serendipitous ALMA observations of a strong gamma-ray flare
The launching mechanism of the jets of active galactic nuclei is
observationally poorly constrained, due to the large distances to these objects
and the very small scales (sub-parsec) involved. In order to better constrain
theoretical models, it is especially important to get information from the
region close to the physical base of the jet, where the plasma acceleration
takes place. In this paper, we report multi-epoch and multi-frequency continuum
observations of the z=2.5 blazar PKS1830-211 with ALMA, serendipitously
coincident with a strong -ray flare reported by Fermi-LAT. The blazar
is lensed by a foreground z=0.89 galaxy, with two bright images of the compact
core separated by 1". Our ALMA observations individually resolve these two
images (although not any of their substructures), and we study the change of
their relative flux ratio with time (four epochs spread over nearly three times
the time delay between the two lensed images) and frequency (between 350 and
1050 GHz, rest-frame of the blazar), during the -ray flare. In
particular, we detect a remarkable frequency-dependent behaviour of the flux
ratio, which implies the presence of a chromatic structure in the blazar (i.e.,
a core-shift effect). We rule out the possiblity of micro- and milli-lensing
effects and propose instead a simple model of plasmon ejection in the blazar's
jet to explain the time and frequency variability of the flux ratio. We suggest
that PKS1830-211 is likely one of the best sources to probe the activity at the
base of a blazar's jet at submillimeter wavelengths, thanks to the peculiar
geometry of the system. The implications of the core-shift in absorption
studies of the foreground z=0.89 galaxy (e.g., constraints on the cosmological
variations of fundamental constants) are discussed.Comment: Accepted for publication in A&
Efeito de altas concentrações de tanino condensado sobre parâmetros ruminais, colonização microbiana e atividade endoglucanase em caprinos.
Structure formation in a colliding flow: The Herschel view of the Draco nebula
The Draco nebula is a high Galactic latitude interstellar cloud likely to
have been formed by the collision of a Galactic halo cloud entering the disk of
the Milky Way. Such conditions are ideal to study the formation of cold and
dense gas in colliding flows of warm gas. We present Herschel-SPIRE
observations that reveal the fragmented structure of the interface between the
infalling cloud and the Galactic layer. This front is characterized by a
Rayleigh-Taylor instability structure. From the determination of the typical
length of the periodic structure (2.2 pc) we estimated the gas kinematic
viscosity and the turbulence dissipation scale (0.1 pc) that is compatible with
that expected if ambipolar diffusion is the main mechanism of energy
dissipation in the WNM. The small-scale structures of the nebula are typical of
that seen in some molecular clouds. The gas density has a log-normal
distribution with an average value of cm. The size of the
structures is 0.1-0.2 pc but this estimate is limited by the resolution of the
observations. The mass ranges from 0.2 to 20 M and the distribution
of the more massive clumps follows a power law . We
identify a mass-size relation with the same exponent as that found in GMCs
() but only 15% of the mass of the cloud is in gravitationally
bound structures. We conclude that the increase of pressure in the collision is
strong enough to trigger the WNM-CNM transition caused by the interplay between
turbulence and thermal instability as self-gravity is not dominating the
dynamics.Comment: 16 pages, A&A, in pres
An ALMA Early Science survey of molecular absorption lines toward PKS1830-211 -- Analysis of the absorption profiles
We present the first results of an ALMA spectral survey of strong absorption
lines for common interstellar species in the z=0.89 molecular absorber toward
the lensed blazar PKS1830-211. The dataset brings essential information on the
structure and composition of the absorbing gas in the foreground galaxy. In
particular, we find absorption over large velocity intervals (gtrsim 100 km/s)
toward both lensed images of the blazar. This suggests either that the galaxy
inclination is intermediate and that we sample velocity gradients or streaming
motions in the disk plane, that the molecular gas has a large vertical
distribution or extraplanar components, or that the absorber is not a simple
spiral galaxy but might be a merger system. The number of detected species is
now reaching a total of 42 different species plus 14 different rare
isotopologues toward the SW image, and 14 species toward the NE line-of-sight.
The abundances of CH, H2O, HCO+, HCN, and NH3 relative to H2 are found to be
comparable to those in the Galactic diffuse medium. Of all the lines detected
so far toward PKS1830-211, the ground-state line of ortho-water has the deepest
absorption. We argue that ground-state lines of water have the best potential
for detecting diffuse molecular gas in absorption at high redshift.Comment: Accepted for publication in A&
Constraining the Thermal Dust Content of Lyman-Break Galaxies in an Overdense Field at z~5
We have carried out 870 micron observations in the J1040.7-1155 field, known
to host an overdensity of Lyman break galaxies at z=5.16 +/- 0.05. We do not
detect any individual source at the S(870)=3.0 mJy/beam (2 sigma) level. A
stack of nine spectroscopically confirmed z>5 galaxies also yields a
non-detection, constraining the submillimeter flux from a typical galaxy at
this redshift to S(870)<0.85 mJy, which corresponds to a mass limit
M(dust)<1.2x10^8 M_sun (2 sigma). This constrains the mass of thermal dust in
distant Lyman break galaxies to less than one tenth of their typical stellar
mass. We see no evidence for strong submillimeter galaxies associated with the
ultraviolet-selected galaxy overdensity, but cannot rule out the presence of
fainter, less massive sources.Comment: 5 pages, 2 figures. MNRAS in pres
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