67 research outputs found
Effect of Lignosilicon on the Content and Antioxidant Activity of the Polyphenols of Buckwheat Fagopyrum esculentum Moench
Lignin preparations, introduced into soil jointly with buckwheat Fagopyrum esculentum Moench, variety 'Aiva' (cultivated throughout Latvia) seeds during the sowing in quantities of 20 kg ha-1 and 40 kg ha-1, exerted a favourable effect on the ned in alcohol extracts from the biomass of different morphological parts of buckwheat, were represented mainly by rutin. The content of rutin in the ethanol extracts from the biomass of flowers with bract reached the maximum values in the phase of accomplishing blooming - beginning of fruit formation to be 2.74% in terms of dry mass (exceeding the rutin content development of plants and the synthesis of flavonoids in flowers with bract. Flavonoids, determin the control by 65%) in the variant with 40 kg ha-1 of Lignosilicon. Lignin preparations favoured the increase in the radical scavenging capacity of the alcohol extracts of the biomass of flowers with bract of buckwheat, as well as grain and hulls. The increment of the buckwheat grain crop, in comparison with the control on the background of 40 kg ha-1 of lignin, was 12%, and that on the background of 20 kg ha-1 and 40 kg/ha of Lignosilicon 10% and 15%, respectively
How Dry Are Red Mergers?
The focus of current research in galaxy evolution has increasingly turned to
understanding the effect that mergers have on the evolution of systems on the
red sequence. For those interactions purported to occur dissipationlessly (so
called "dry mergers"), it would appear that the role of gas is minimal.
However, if these mergers are not completely dry, then even low levels of gas
may be detectable. The purpose of our study is to test whether early type
galaxies with HI in or around them, or "wet" ellipticals, would have been
selected as dry mergers by the criteria in van Dokkum (2005, AJ, 130, 2647). To
that end, we examine a sample of 20 early types from the HI Rogues Gallery with
neutral hydrogen in their immediate environs. Of these, the 15 brightest and
reddest galaxies match the optical dry merger criteria, but in each case, the
presence of HI means that they are not truly dry.Comment: 8 pages plus 1 table and 5 figures; accepted for publication in A
A Gaseous Group with Unusual Remote Star Formation
We present VLA 21-cm observations of the spiral galaxy ESO 481-G017 to
determine the nature of remote star formation traced by an HII region found 43
kpc and ~800 km s^-1 from the galaxy center (in projection). ESO 481-G017 is
found to have a 120 kpc HI disk with a mass of 1.2x10^10 Msun and UV GALEX
images reveal spiral arms extending into the gaseous disk. Two dwarf galaxies
with HI masses close to 10^8 Msun are detected at distances of ~200 kpc from
ESO 481-G017 and a HI cloud with a mass of 6x10^7 Msun is found near the
position and velocity of the remote HII region. The HII region is somewhat
offset from the HI cloud spatially and there is no link to ESO 481-G017 or the
dwarf galaxies. We consider several scenarios for the origin of the cloud and
HII region and find the most likely is a dwarf galaxy that is undergoing ram
pressure stripping. The HI mass of the cloud and Halpha luminosity of the HII
region (10^38.1 erg s^-1) are consistent with dwarf galaxy properties, and the
stripping can trigger the star formation as well as push the gas away from the
stars.Comment: 19 pages, 4 figures, accepted by PAS
Role of paramagnetic polyconjugated clusters in lignin antioxidant activity (in vitro)
Using physico-chemical methods (EPR, SEC, Py-GC/MS and UV/VIS spectroscopy) and wet chemical analysis, the characteristics of 6 hardwood lignins in terms of functionality, molecular weight and composition of lignin substructures were determined and considered together with the results of DPPH•, ABTS •+ and O2•- antioxidant assays with the aim to understand the relationships governing antioxidant properties of lignin. The strong positive linear correlation between lignin antioxidant capacity in the three assays used and the extent of conjugation of paramagnetic polyconjugated clusters in lignin macromolecules was found. The biological activity of the most active alkaline lignins was assessed by in vitro experiment with human blood.publishersversionPeer reviewe
HI aperture synthesis and optical observations of the pair of galaxies NGC 6907 and 6908
NGC 6908, a S0 galaxy situated in direction of NGC 6907, was only recently
recognized as a distinct galaxy, instead of only a part of NGC 6907. We present
21 cm radio synthesis observations obtained with the GMRT and optical images
and spectroscopy obtained with the Gemini North telescope of this pair of
interacting galaxies. From the radio observations we obtained the velocity
field and the HI column density map of the whole region containing the NGC
6907/8 pair, and by means of the Gemini multi-object spectroscopy we obtained
high quality photometric images and resolution spectra sampling the
two galaxies. By comparing the rotation curve of NGC 6907 obtained from the two
opposite sides around the main kinematic axis, we were able to distinguish the
normal rotational velocity field from the velocity components produced by the
interaction between the two galaxies. Taking into account the rotational
velocity of NGC 6907 and the velocity derived from the absorption lines for NGC
6908, we verified that the relative velocity between these systems is lower
than 60 km s. The emission lines observed in the direction of NGC 6908,
not typical of S0 galaxies, have the same velocity expected for the NGC 6907
rotation curve. Some of them, superimposed on the absorption profiles, which
reinforces the idea that they were not formed in NGC 6908. Finally, the HI
profile exhibits details of the interaction, showing three components: one for
NGC 6908, another for the excited gas in the NGC 6907 disk and a last one for
the gas with higher relative velocities left behind NGC 6908 by dynamical
friction, used to estimate the time when the interaction started in years ago.Comment: 11 pages, 5 tables, 13 figures. Corrected typos. Accepted for
publication in MNRAS. The definitive version will be available at
http://www.blackwell-synergy.co
Cosmicflows-2: I-band Luminosity - HI Linewidth Calibration
In order to measure distances with minimal systematics using the correlation
between galaxy luminosities and rotation rates it is necessary to adhere to a
strict and tested recipe. We now derive a measure of rotation from a new
characterization of the width of a neutral Hydrogen line profile. Additionally,
new photometry and zero point calibration data are available. Particularly the
introduction of a new linewidth parameter necessitates the reconstruction and
absolute calibration of the luminosity-linewidth template. The slope of the new
template is set by 267 galaxies in 13 clusters. The zero point is set by 36
galaxies with Cepheid or Tip of the Red Giant Branch distances. Tentatively, we
determine H0 = 75 km s-1 Mpc-1. Distances determined using the
luminosity-linewidth calibration will contribute to the distance compendium
Cosmicflows-2.Comment: Accepted for publication in The Astrophysical Journal, 27 pages, 18
figure
Evidences of merging in the Seyfert galaxy NGC 3393 revealed by modelling the spectra
The discovery of two active black holes in the Seyfert galaxy NGC 3393,
separated by about 490 light years, revealed a merging event. This led us to
look for other evidences of galaxy collision and merging through the analysis
of the observed spectra in different frequency ranges. We found preshock
densities higher by a factor of about 10 in the NGC 3393 NLR than in other AGN
and patches of ionized matter beyond the observed NLR bulk. They can be
explained by compression and heating of the gas downstream of shock waves
created by collision. Metallicity in terms of the O/H relative abundance, is
about 0.78 solar. Mg/H depletion by a factor of about 3 compared with solar
cannot be explained by Mg trapping into dust grains, due to rather high shock
velocities. The low O/H and Mg/H abundances indicate mixing with external
matter during collision. Twice solar N/H is predicted by modelling the spectra
of high shock velocity clouds reached by a Ts =8.6 10^4 K black-body flux. This
suggests that Wolf-Rayet stars could be created by galaxy collision in the
central region.Comment: 11 pages, 3 figures, 3 tables, accepted for publication in MNRA
A study of the neglected Galactic HII region NGC 2579 and its companion ESO 370-9
The Galactic HII region NGC 2579 has stayed undeservedly unexplored due to
identification problems which persisted until recently. Both NGC 2579 and its
companion ESO 370-9 have been misclassified as planetary or reflection nebula,
confused with each other and with other objects. Due to its high surface
brightness, high excitation, angular size of few arcminutes and relatively low
interstellar extinction, NGC 2579 is an ideal object for investigations in the
optical range. Located in the outer Galaxy, NGC 2579 is an excellent object for
studying the Galactic chemical abundance gradients. In this paper we present
the first comprehensive observational study on the nebular and stellar
properties of NGC 2579 and ESO 370-9, including the determination of electron
temperature, density structure, chemical composition, kinematics, distance, and
the identification and spectral classification of the ionizing stars, and
discuss the nature of ESO 370-9. Long slit spectrophotometric data in the
optical range were used to derive the nebular electron temperature, density and
chemical abundances and for the spectral classification of the ionizing star
candidates. Halpha and UBV CCD photometry was carried out to derive stellar
distances from spectroscopic parallax and to measure the ionizing photon flux.Comment: To be published in Astronomy & Astrophysic
The High-Metallicity Explosion Environment of the Relativistic Supernova 2009bb
We investigate the environment of the nearby (d ~ 40Mpc) broad-lined Type Ic
supernova SN 2009bb. This event was observed to produce a relativistic outflow
likely powered by a central accreting compact object. While such a phenomenon
was previously observed only in long-duration gamma-ray bursts (LGRBs), no LGRB
was detected in association with SN 2009bb. Using an optical spectrum of the SN
2009bb explosion site, we determine a variety of ISM properties for the host
environment, including metallicity, young stellar population age, and star
formation rate. We compare the SN explosion site properties to observations of
LGRB and broad-lined SN Ic host environments on optical emission line ratio
diagnostic diagrams. Based on these analyses, we find that the SN 2009bb
explosion site has a very high metallicity of ~2x solar, in agreement with
other broad-lined SN Ic host environments and at odds with the low-redshift
LGRB host environments and recently proposed maximum metallicity limits for
relativistic explosions. We consider the implications of these findings and the
impact that SN 2009bb's unusual explosive properties and environment have on
our understanding of the key physical ingredient that enables some SNe to
produce a relativistic outflow.Comment: 7 pages, 4 figures, 1 table; accepted for publication in ApJ Letters
(replaced to include missing figure
Deep Near-IR Surface Photometry of 57 Galaxies in the Local Sphere of Influence
We present H-band surface photometry of 57 galaxies drawn from the Local
Sphere of Influence (LSI) with distances of less than 10 Mpc from the Milky
Way. The images with a typical surface brightness limit 4 mag fainter than
2MASS (24.5 mag arcsec^-2 < sb_lim < 26 mag arcsec ^-2) have been obtained with
IRIS2 on the 3.9 m Anglo-Australian Telescope. A total of 22 galaxies that
remained previously undetected in the near-IR and potentially could have been
genuinely young galaxies were found to have an old stellar population with a
star density 1-2 magnitudes below the 2MASS detection threshold. The cleaned
near-IR images reveal the morphology and extent of many of the galaxies for the
first time. For all program galaxies, we derive radial luminosity profiles,
ellipticities, and position angles, together with global parameters such as
total magnitude, mean effective surface brightness and half-light radius. Our
results show that 2MASS underestimates the total magnitude of galaxies with
_eff between 18-21 mag arcsec^-2 by up to 2.5 mag. The Sersic parameters
best describing the observed surface brightness profiles are also presented.
Adopting accurate galaxy distances and a H-band mass-to-light ratio of
Upsilon_H=1.0 +/- 0.4, the LSI galaxies are found to cover a stellar mass range
of 5.6 < log_10 (M_stars) < 11.1. The results are discussed along with
previously obtained optical data. Our sample of low luminosity galaxies is
found to follow closely the optical-infrared B versus H luminosity relation
defined by brighter galaxies with a slope of 1.14 +/- 0.02 and scatter of 0.3
magnitudes. Finally we analyse the luminosity - surface brightness relation to
determine an empirical mass-to-light ratio of Upsilon_H=0.78 +/- 0.08 for
late-type galaxies in the H-band.Comment: Accepted by AJ. High resolution version available at
http://www.mso.anu.edu.au/~emma/KirbyHband.pd
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