3,286 research outputs found
Asymmetrical structure of ionization and kinematics in the Seyfert galaxy NGC 5033
We present integral field spectroscopy of NGC 5033, a low luminosity Seyfert
galaxy. The observations were made with INTEGRAL, a fiber based system
operating at the WHT. The intensity map of the H emission line
represents a spiral or ring-like pattern of HII regions. On the contrary, the
[OIII] intensity map morphology is markedly anisotropic. The strong
morphological differences imply that the [OIII] emitters represent highly
ionized gas illuminated by the central source. The [OIII] map morphology is
compatible with a biconical structure of ionization induced by strong
extinction in the galaxy disc that also obscures half of the spheroidal stellar
bulge. We identify the spectrum corresponding to the Seyfert 1 nucleus from the
presence of H broad emission lines. This spectrum is located in a region
where strong extinction is expected but exhibits the bluest spectral energy
distribution. The Seyfert 1 nucleus seems to be offcenter with respect to the
stellar rotation center. This result has been also found in other Seyfert
galaxies and interpreted in terms of a past merger. The offcentering could
indicate the presence of nonsymmetric departures in the gravitational potential
which could be fueling the active nucleus. The kinematics of the [OIII]
emitters show important deviations at a kpc scale with respect to the stellar
velocity field and show features related to the asymmetrical morphology of the
high ionization region.Comment: 9 pages, accepted for publication in Astronomy and Astrophysics.
Figures 1 and 7 are attached as .gif file
Petrographic characterization of coeval carbonate grains in recent fluvial sands (Serranía de Cuenca, Spain)
Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu
Synthesis of Analogues Based on the Opioid Alkaloid Mitragynine
Opioid analgesics such as morphine and its derivatives are the most frequently prescribed narcotics for the treatment of severe and chronic pain. Among other side effects caused by the administration of these opioid analgesics, physical dependence and addiction are the most undesirable ones. Currently, pharmacological approaches to treat opioid dependence include mainly methadone and LAAM (mu-agonists), buprenorphine (mu-partial agonist) and clonidine (alpha2-adrenergic agonist). Considering the negative aspects of the relapsing nature correlated to opioid dependence, it is important to search for new ways to overcome this problem. The scope of this work is to study novel compounds based on the alkaloids present in Mitragynina speciosa (Korth), a tree indigenous to Southeast Asia. Consumption of leave extracts of this plant have been linked to the attenuation of the withdrawal syndrome associate with opioid dependence. Taking into consideration the structure of the major alkaloid, mitragynine, two classes of compounds were designed and synthesized: phenylpiperidines, including phenylaminopiperidines and phenylamidopiperidines, and tetrahydro-beta-carbolines. They were further submitted to in vitro evaluation on mu, delta and kappa-opioid receptors for their binding affinities. Out of six piperidines submitted to biological evaluation, four revealed significant affinity with Ki values in the micromolar range on either mu- and delta-receptors or kappa-opioid receptors. On the other hand, out of five tetrahydro-beta-carbolines tested, two shokappa-receptors affinities in the nanomolar range. Although none of the compounds displayed binding affinities as high as mitragynine, it is possible to say that distinct moieties attached to the piperidines had different selectivities among mu-, delta- and kappa-opioid receptors. Tetrahydro-beta-carbolines, which mimics the four-ringed structure of mitragynine, shoonly relevant affinity towards kappa-receptors. The important factor for the higher affinity of tetrahydro-beta-carbolines, when compared to piperidines, is that their less flexible structure is responsible for their greater affinity. More specifically, the methyl acetyl moiety at the C15 position had higher affinity than the methyl methoxyacrylate on kappa-receptors. Unfortunately, this work did not focus on stereoselective syntheses or chiral separations, which in the case of the chiral tetrahydro-beta-carbolines could have given valuable insights about the spatial requirements for affinity among the three main opioid receptors
Los ejemplares tipo y figurados de las colecciones paleontológicas del Museo Geominero. I. Invertebrados e icnofósiles paleozoicos
Entre la colección de invertebrados e icnofósiles paleozoicos del Museo Geominero se ha detectado la presencia de 501 ejemplares figurados, de los que 135 son ejemplares tipo. Todos ellos son fósiles españoles, a excepción de 28 procedentes de Marruecos y del Sáhara Occidental. Los datos obtenidos se han almacenado en una base de datos temática, que permite un fácil acceso y consulta de la información. El estudio de estas colecciones forma parte de un proyecto más amplio, en el que se contempla también la investigación de los fósiles e icnofósiles mesozoicos y cenozoicos, que supondrá la revalorización científica y patrimonial de los fondos del Museo Geominero
A detailed two-dimensional stellar population study of M32
We present Two-Dimensional Spectroscopy of the 9x12 arcsec^2 central region
of M32 obtained with the 2D_FIS fibre spectrograph installed at the William
Herschel Telescope. From these spectra line strength maps have been
reconstructed for about 20 absorption lines, mostly belonging to the Lick
system. We find good agreement with long-slit line strength profiles in the
literature. In contrast with previous studies, indices were azimuthally
averaged along continuum isophotes of M32. A remarkable result is that no
gradients are presented in the spectral indices. So, we have fitted the mean
values of each spectral index and central colours to the models of Vazdekis et
al. (1996) and Worthey (1994), finding that an intermediate age (~4 Gyr) and
metallicity similar to solar (Z=0.02) are the best fitted values for the
innermost region of M32.Comment: accepted in MNRA
Detrital modes in sedimenticlastic sands from low-order streams in the Iberian Range, Spain: the potential for sand generation by different sedimentary rocks
The composition of modern stream sands derived from sedimentary source rocks in the Iberian Range has been analyzed in
order to evaluate the contributions of the different bedrock types (mainly sandstones, limestones and dolostones). Temperate to
subhumid climate and short transport conditions promote a weathering-limited denudation regime. As expected, sand
composition proved to be essentially quartzolithic, with variable amounts of penecontemporaneous carbonates.
Sand compositional data were compared with the exposure areas of the different bedrocks in the drainage sub-basins
considered for semi-quantitative assessment of the sand generation potential of each bedrock type. Siliciclastic formations
(sandstones) appear to be by far the most significant sand producers, with Sand Generation Indices (SGIs) in the medium sand
fraction ranging from 4 to 20; i.e., 4 to 20 times greater than the SGI of carbonate rocks. Composition and texture are the main
factors controlling carbonate sand generation. Sparitic limestones yield higher SGIs (2.8 to 20) when source terrains are
constituted exclusively by carbonate rocks. High sparite grain content in the sands is enhanced by supplies from additional
sources, such as calcitized dolostones. Dolomicrite sources are strongly under-represented in the sands analyzed (very low SGI),
whereas the proportion of micritic limestone grains tends to be an accurate reflection of that bedrock at the source.
Even though the results presented here refer to the first stage of sand generation with negligible transport effects, we think
they may be helpful in the analysis and reconstruction of source terrains in ancient sedimenticlastic deposit
Non-circular motion evidences in the circumnuclear region of M100 (NGC 4321)
We analyse new integral field spectroscopy of the inner region (central 2.5
kpc) of the spiral galaxy NGC 4321 to study the peculiar kinematics of this
region. Fourier analysis of the velocity residuals obtained by subtracting an
axisymmetric rotation model from the velocity field, indicates
that the distortions are {\em global} features generated by an
perturbation of the gravitational potential which can be explained by the
nuclear bar. This bar has been previously observed in the near-infrared but not
in the optical continuum dominated by star formation. We detect the optical
counterpart of this bar in the 2D distribution of the old stellar population
(inferred from the equivalent width map of the stellar absorption lines). We
apply the Tremaine--Weinberg method to the stellar velocity field to calculate
the pattern speed of the inner bar, obtaining a value of
=160. This value is considerably la
rger than the one obtained when a simple bar model is considered. However the
uncertainties in the pattern speed determination prevent us to give support to
alternative scenarios.Comment: 11 pages, 11 figures, accepted for publication in MNRA
Integral field optical spectroscopy of a representative sample of ULIRGs: I. The Data
We present a project aimed at studying the structure, dust distribution,
ionization state, and kinematics of a representative sample of 22 ULIRGs. The
galaxies in the sample undergo different merger phases (they are evenly divided
between pre- and post-coalescence systems) and ionization stages (27% HII, 32%
LINER, 18% Seyfert, and 23% mixed classifications) over a wide infrared
luminosity range (11.8<Lir/Lsun<12.6), which also includes some galaxies of low
luminosity. The main aims of this paper are to present the sample and discuss
the structure of the stellar and ionized gas components. Our results imply that
evolution caused by a merger is occurring in the ionized gas structure of
ULIRGs. The present study relies on the use of integral field optical
spectroscopy data obtained with the INTEGRAL instrument at the 4.2 m William
Herschel Telescope.Comment: To appear in A&A. Paper with higher quality images can be found at
http://hera.ph1.uni-koeln.de/ftpspace/maca/Catalog
FeNi-based magnetoimpedance multilayers: Tailoring of the softness by magnetic spacers
The microstructure and magnetic properties of sputtered permalloy films and FeNi(170 nm)/X/FeNi(170 nm) (X=Co, Fe, Gd, Gd-Co) sandwiches were studied. Laminating of the thick FeNi film with various spacers was done in order to control the magnetic softness of FeNi-based multilayers. In contrast to the Co and Fe spacers, Gd and Gd-Co magnetic spacers improved the softness of the FeNi/X/FeNi sandwiches. The magnetoimpedance responses were measured for [FeNi/Ti(6 nm)] 2/FeNi and [FeNi/Gd(2 nm)] 2/FeNi multilayers in a frequency range of 1-500 MHz: for all frequencies under consideration the highest magnetoimpedance variation was observed for [FeNi/Gd(2 nm)] 2/FeNi multilayers. © 2012 American Institute of Physics
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