Efeito modulador do retinol no turnover de fosfoinositídios em culturas de células de Sertoli de ratos imaturos

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Ação do retinol em células de Sertoli : efeito sobre o metabolismo da esfingomielina

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Model-Independent Diagnostics of Highly Reddened Milky Way Star Clusters: Age Calibration

The next generation near- and mid-infrared Galactic surveys will yield a large number of new highly obscured star clusters. Detailed characterization of these new objects with spectroscopy is time-consuming. Diagnostic tools that will be able to characterize clusters based only on the available photometry will be needed to study large samples of the newly found objects. The brightness difference between the red clump and the main-sequence turn-off point have been used as a model-independent age calibrator for clusters with ages from a few 10$^8$ to 10$^{10}$ yr in the optical. Here we apply for the first time the method in the near-infrared. We calibrated this difference in $K$-band, which is likely to be available for obscured clusters, and we apply it to a number of test clusters with photometry comparable to the one that will be yielded by the current or near-future surveys. The new calibration yields reliable ages over the range of ages for which the red clump is present in clusters. The slope of the relation is smoother than that of the corresponding $V$-band relation, reducing the uncertainty in the age determinations with respect to the optical ones.Comment: 5 pages, 5 eps figure, accepted for publication in Astronomy and Astrophysic

The Evolved Red Stellar Content of M32

Near-infrared images obtained with the CFHT AOB are used to investigate the stellar content of the Local Group elliptical galaxy M32. Observations of a field 2.3 arcmin from the galaxy center reveal a large population of AGB stars, and comparisons with models indicate that these objects have an age log(t_Gyr) < 9.3. It is concluded that intermediate age stars account for roughly 25% of the total K light and 10% +/- 5% of the mass in this field. The K LF of bright sources between 20 and 30 arcsec from the nucleus is well matched by the LF of the outer regions of the galaxy after accounting for differences in surface brightness and correcting for crowding. It is concluded that the relative size of the intermediate age component with respect to other populations does not change with radius over most of the galaxy. However, the integrated J-K color and 2.3 micron CO index change with radius within a few tenths of an arcsec of the galaxy center indicating that, contrary to what might be inferred from observations at visible wavelengths, the integrated photometric properties of the central regions of M32 differ from those of the surrounding galaxy.Comment: 18 pages, 9 postscript figures, to appear in the PAS

A multi-wavelength census of star formation activity in the young embedded cluster around Serpens/G3-G6

Aims. The aim of this paper is to characterise the star formation activity in the poorly studied embedded cluster Serpens/G3-G6, located ~ 45' (3 pc) to the south of the Serpens Cloud Core, and to determine the luminosity and mass functions of its population of Young Stellar Objects (YSOs). Methods. Multi-wavelength broadband photometry was obtained to sample the near and mid-IR spectral energy distributions to separate YSOs from field stars and classify the YSO evolutionary stage. ISOCAM mapping in the two filters LW2 (5-8.5 um) and LW3 (12-18 um) of a 19' x 16' field was combined with JHKs data from 2MASS, Ks data from Arnica/NOT, and L' data from SIRCA/NOT. Continuum emission at 1.3 mm (IRAM) and 3.6 cm (VLA) was mapped to study the cloud structure and the coldest/youngest sources. Deep narrow band imaging at the 2.12 um S(1) line of H2 from NOTCam/NOT was obtained to search for signs of bipolar outflows. Results. We have strong evidence for a stellar population of 31 Class II sources, 5 flat-spectrum sources, 5 Class I sources, and two Class 0 sources. Our method does not sample the Class III sources. The cloud is composed of two main dense clumps aligned along a ridge over ~ 0.5 pc plus a starless core coinciding with absorption features seen in the ISOCAM maps. We find two S-shaped bipolar collimated flows embedded in the NE clump, and propose the two driving sources to be a Class 0 candidate (MMS3) and a double Class I (MMS2). For the Class II population we find a best age of ~ 2 Myr and compatibility with recent Initial Mass Functions (IMFs) by comparing the observed Class II luminosity function (LF), which is complete to 0.08 L_sun, to various model LFs with different star formation scenarios and input IMFs.Comment: 18 pages, 16 figures, 3 online tables, accepted by A&

Identificação de glicosil fosfatidilinositol em testículos de rato

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The young stellar population in the Serpens Cloud Core: An ISOCAM survey

We present results from an ISOCAM survey in the two broad band filters LW2 (5-8.5 mu) and LW3 (12-18 mu) of a 0.13 square degree coverage of the Serpens Main Cloud Core. A total of 392 sources were detected in the 6.7 mu band and 139 in the 14.3 mu band to a limiting sensitivity of ~ 2 mJy. Only about 50% of the mid-IR excess sources show excesses in the near-IR J-H/H-K diagram. In the central Cloud Core the Class I/Class II number ratio is 19/18, i.e. about 10 times larger than in other young embedded clusters such as rho Ophiuchi or Chamaeleon. The mid-IR fluxes of the Class I and flat-spectrum sources are found to be on the average larger than those of Class II sources. Stellar luminosities are estimated for the Class II sample, and its luminosity function is compatible with a coeval population of about 2 Myr which follows a three segment power-law IMF. For this age about 20% of the Class IIs are found to be young brown dwarf candidates. The YSOs are in general strongly clustered, the Class I sources more than the Class II sources, and there is an indication of sub-clustering. The sub-clustering of the protostar candidates has a spatial scale of 0.12 pc. These sub-clusters are found along the NW-SE oriented ridge and in very good agreement with the location of dense cores traced by millimeter data. The smallest clustering scale for the Class II sources is about 0.25 pc, similar to what was found for rho Ophiuchi. Our data show evidence that star formation in Serpens has proceeded in several phases, and that a ``microburst'' of star formation has taken place very recently, probably within the last 10^5 yrs.Comment: 25 pages, 14 figures, accepted by A&A March 18th, see also http://www.not.iac.es/~amanda

The UKIDSS-2MASS Proper Motion Survey I: Ultracool dwarfs from UKIDSS DR4

The UKIRT Infrared Deep Sky Survey (UKIDSS) is the first of a new generation of infrared surveys. Here we combine the data from two UKIDSS components, the Large Area Survey (LAS) and the Galactic Cluster Survey (GCS), with 2MASS data to produce an infrared proper motion survey for low mass stars and brown dwarfs. In total we detect 267 low mass stars and brown dwarfs with significant proper motions. We recover all ten known single L dwarfs and the one known T dwarf above the 2MASS detection limit in our LAS survey area and identify eight additional new candidate L dwarfs. We also find one new candidate L dwarf in our GCS sample. Our sample also contains objects from eleven potential common proper motion binaries. Finally we test our proper motions and find that while the LAS objects have proper motions consistent with absolute proper motions, the GCS stars may have proper motions which are significantly under-estimated. This is due possibly to the bulk motion of some of the local astrometric reference stars used in the proper motion determination.Comment: Accepted for publication in MNRA

The WFCAM Science Archive

We describe the WFCAM Science Archive (WSA), which is the primary point of access for users of data from the wide-field infrared camera WFCAM on the United Kingdom Infrared Telescope (UKIRT), especially science catalogue products from the UKIRT Infrared Deep Sky Survey (UKIDSS). We describe the database design with emphasis on those aspects of the system that enable users to fully exploit the survey datasets in a variety of different ways. We give details of the database-driven curation applications that take data from the standard nightly pipeline-processed and calibrated files for the production of science-ready survey datasets. We describe the fundamentals of querying relational databases with a set of astronomy usage examples, and illustrate the results.Comment: 28 pages, 18 figures; accepted for publication in MNRAS (2007 November 8

Effect of uncaria tomentosa extract on purinergic enzyme activities in lymphocytes of rats submitted to experimental adjuvant arthritis model

Background: Considering that adjuvant arthritis is an experimental model of arthritis widely used for preclinical testing of numerous anti-arthritic agents, which were taken by a large number of patients worldwide, it is of great interest to investigate the therapeutic action of compounds with anti-inflammatory properties, such as Uncaria tomentosa extract. Moreover, there are no studies demonstrating the effect of U. tomentosa on the metabolism of adenine nucleotides published so far. Thus, the purpose of the present study is to investigate the effects of U. tomentosa extract on E-NTPDase and E-ADA activities in lymphocytes of Complete Freund’s Adjuvant (CFA) arthritis induced rats. Methods: To evaluate the effect of U. tomentosa extract on the activity of E-NTPDase and ADA in lymphocytes, the rats were submitted to an experimental adjuvant arthritis model. Peripheral lymphocytes were isolated and E-NTPDase and E-ADA activities were determined. Data were analyzed by a one- or two-way ANOVA. Post hoc analyses were carried out by the Student-Newman-Keuls (SNK) Multiple Comparison Test. Results: E-NTPDase activity was increased in arthritic untreated. Arthritic rats which received U. tomentosa extract, presented similar results to the control group. However, results obtained for adenosine hydrolysis by E-ADA were not altered in arthritic rats. U. tomentosa extract did not alter E-NTPDase and E-ADA activity in healthy animals. Conclusions: The present investigation supports the hypothesis that the increased E-NTPDase activity verified in arthritic rats might be an attempt to maintain basal levels of ATP and ADP in the extracellular medium, since the arthritis induction causes tissue damage and, consequently, large amounts of ATP are released into this milieu. Also, it highlights the possibility to use U. tomentosa extract as an adjuvant to treat arthritis