THE GEMINI NICI PLANET-FINDING CAMPAIGN: DISCOVERY OF A SUBSTELLAR L DWARF COMPANION TO THE NEARBY YOUNG M DWARF CD-35 2722

We present the discovery of a wide (67 AU) substellar companion to the nearby (21 pc) young solar-metallicity M1 dwarf CD-35 2722, a member of the approximate to 100 Myr AB Doradus association. Two epochs of astrometry from the NICI Planet-Finding Campaign confirm that CD-35 2722 B is physically associated with the primary star. Near-IR spectra indicate a spectral type of L4 +/- 1 with a moderately low surface gravity, making it one of the coolest young companions found to date. The absorption lines and near-IR continuum shape of CD-35 2722 B agree especially well the dusty field L4.5 dwarf 2MASS J22244381-0158521, while the near-IR colors and absolute magnitudes match those of the 5 Myr old L4 planetary-mass companion, 1RXS J160929.1-210524 b. Overall, CD-35 2722 B appears to be an intermediate-age benchmark for L dwarfs, with a less peaked H-band continuum than the youngest objects and near-IR absorption lines comparable to field objects. We fit Ames-Dusty model atmospheres to the near-IR spectra and find T(eff) = 1700-1900 K and log(g) = 4.5 +/- 0.5. The spectra also show that the radial velocities of components A and B agree to within +/- 10 km s(-1), further confirming their physical association. Using the age and bolometric luminosity of CD-35 2722 B, we derive a mass of 31 +/- 8 M(Jup) from the Lyon/Dusty evolutionary models. Altogether, young late-M to mid-L type companions appear to be overluminous for their near-IR spectral type compared with field objects, in contrast to the underluminosity of young late-L and early-T dwarfs.

One, two or no record of late neoproterozoic glaciation in South-East Cameroon?

Severe climate changes culminating in at least three major glacial events have been recognized in the Neoproterozoic sedimentary record from many parts of the world Supportive to the global nature of these climatic shifts a considerable amount of data have been acquired from deposits exposed in Pan-African orogenic belts in southwestern and western Africa By comparison published data from the Pan-African belts in Central Africa are scarce We report here evidence of possibly two glacial events recorded in the Mintom Formation that is located on the margin of the Pan-African orogenic Yaounde belt in South-East Cameroon In the absence of reliable radiometric data only maximum and minimum age limits of 640 and 580 Ma respectively can at present be applied to the Mintom Formation The formation consists of two lithostratigraphic ensembles each subdivided in two members (i e in ascending stratigraphic order the Kol Metou Momibole and Atog Adjap Members) The basal ensemble exhibits a typical glacial to post-glacial succession It includes diamictites comprising cobbles and boulders in a massive argillaceous siltstone matrix and laminated siltstones followed by in sharp contact a 2 m-thick massive dolostone that yielded negative delta(13)C values (<-3 parts per thousand. V-PDB) similar to those reported for Marinoan cap carbonates elsewhere However uncertainty remains regarding the glacial influence on the siliciclastic facies because the diamictite is better explained as a mass-flow deposit and diagnostic features such as dropstones have not been seen in the overlying siltstones The Mintom Formation may thus provide an example of an unusual succession of non-glacial diamictite overlain by a truly glacial melt-related cap-carbonate We also report the recent discovery of ice-striated pavements on the structural surface cut in the Mintom Formation suggesting that glaciers developed after the latter had been deposited and deformed during the Pan-African orogeny Striations which consistently exhibit two principal orientations (N60 and N110) were identified in two different localities in the west of the study area on siltstones of the Kol Member and in the east on limestones of the Atog Adjap Member respectively N60-oriented striae indicate ice flow towards the WSW Assigning an age to these features remains problematical because they were not found associated with glaciogenic deposits Two hypotheses can equally be envisaged e either the striated surfaces are correlated (1) to the Gaskiers (or Neoproterozoic post-Gaskiers) glaciation and represent the youngest Ediacaran glacial event documented in the southern Yaounde belt or (2) to the Late Ordovician Hirnantian (Saharan) glaciation thereby providing new data about Hirnantian ice flows in Central Africa (C) 2010 Elsevier Ltd All rights reserved

Late Quaternary drainage dynamics in northern Brazil based on the study of a large paleochannel from southwestern Marajó Island

Marajó Island shows an abundance of paleochannels easily mapped in its eastern portion, where vegetation consists mostly of savannas. SRTM data make possible to recognize paleochannels also in western Marajó, even considering the dense forest cover. A well preserved paleodrainage network from the adjacency of the town of Breves (southwestern Marajó Island) was investigated in this work combining remote sensing and sedimentological studies. The palimpsest drainage system consists of a large meander connected to narrower tributaries. Sedimentological studies revealed mostly sharp-based, fining upward sands for the channelized features, and interbedded muds and sands for floodplain areas. The sedimentary structures and facies successions are in perfect agreement with deposition in channelized and floodplain environments, as suggested by remote sensing mapping. The present study shows that this paleodrainage was abandoned during Late Pleistocene, slightly earlier than the Holocene paleochannel systems from the east part of the island. Integration of previous studies with the data available herein supports a tectonic origin, related to the opening of the Pará River along fault lineaments. This would explain the disappearance of large, north to northeastward migrating channel systems in southwestern Marajó Island, which were replaced by the much narrower, south to southeastward flowing modern channels.

Paleoproductivity changes during the Late Quaternary in the southeastern Brazilian upper continental margin of the Southwestern Atlantic

Changes in the Brazilian continental margins oceanic productivity and circulation over the last 27,000 years were reconstructed based on sedimentological and microfaunal analyses. Our results suggest that oceanic paleoproductivity and the supply of terrigenous sediments to the Brazilian continental margin were higher during the Last Glacial Maximum (LGM) than during the Holocene. These changes may have been primarily influenced by significant sea level fluctuations that have occurred since the late Pleistocene. During the LGM, the lower sea level, higher productivity and lower sea-surface paleotemperatures may have been the result of the offshore displacement of the main flow of the Brazil Current. However, during the Holocene, the warm waters of the Brazil Current were displaced toward the coast. This displacement contributed to the increase in water temperature and prevented an increase in oceanic productivity. The decrease in terrigenous supply since the LGM could be related to the increase of the extension of the continental shelf and/or drier climatic conditions.

Chicken skeletal muscle-associated macroarray for gene discovery

Macro- and microarrays are well-established technologies to determine gene functions through repeated measurements of transcript abundance. We constructed a chicken skeletal muscle-associated array based on a muscle-specific EST database, which was used to generate a tissue expression dataset of similar to 4500 chicken genes across 5 adult tissues (skeletal muscle, heart, liver, brain, and skin). Only a small number of ESTs were sufficiently well characterized by BLAST searches to determine their probable cellular functions. Evidence of a particular tissue-characteristic expression can be considered an indication that the transcript is likely to be functionally significant. The skeletal muscle macroarray platform was first used to search for evidence of tissue-specific expression, focusing on the biological function of genes/transcripts, since gene expression profiles generated across tissues were found to be reliable and consistent. Hierarchical clustering analysis revealed consistent clustering among genes assigned to 'developmental growth', such as the ontology genes and germ layers. Accuracy of the expression data was supported by comparing information from known transcripts and tissue from which the transcript was derived with macroarray data. Hybridization assays resulted in consistent tissue expression profile, which will be useful to dissect tissue-regulatory networks and to predict functions of novel genes identified after extensive sequencing of the genomes of model organisms. Screening our skeletal-muscle platform using 5 chicken adult tissues allowed us identifying 43 'tissue-specific' transcripts, and 112 co-expressed uncharacterized transcripts with 62 putative motifs. This platform also represents an important tool for functional investigation of novel genes; to determine expression pattern according to developmental stages; to evaluate differences in muscular growth potential between chicken lines, and to identify tissue-specific genes.

A New Baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the Late Cretaceous of Brazil and the Phylogeny of Baurusuchidae

Background: Baurusuchidae is a group of extinct Crocodyliformes with peculiar, dog-faced skulls, hypertrophied canines, and terrestrial, cursorial limb morphologies. Their importance for crocodyliform evolution and biogeography is widely recognized, and many new taxa have been recently described. In most phylogenetic analyses of Mesoeucrocodylia, the entire clade is represented only by Baurusuchus pachecoi, and no work has attempted to study the internal relationships of the group or diagnose the clade and its members. Methodology/Principal Findings: Based on a nearly complete skull and a referred partial skull and lower jaw, we describe a new baurusuchid from the Vale do Rio do Peixe Formation (Bauru Group), Late Cretaceous of Brazil. The taxon is diagnosed by a suite of characters that include: four maxillary teeth, supratemporal fenestra with equally developed medial and anterior rims, four laterally visible quadrate fenestrae, lateral Eustachian foramina larger than medial Eustachian foramen, deep depression on the dorsal surface of pterygoid wing. The new taxon was compared to all other baurusuchids and their internal relationships were examined based on the maximum parsimony analysis of a discrete morphological data matrix. Conclusion: The monophyly of Baurusuchidae is supported by a large number of unique characters implying an equally large morphological gap between the clade and its immediate outgroups. A complex phylogeny of baurusuchids was recovered. The internal branch pattern suggests two main lineages, one with a relatively broad geographical range between Argentina and Brazil (Pissarrachampsinae), which includes the new taxon, and an endemic clade of the Bauru Group in Brazil (Baurusuchinae).

Discovery of VVV CL001 A low-mass globular cluster next to UKS 1 in the direction of the Galactic bulge

Context. It is not known how many globular clusters may remain undetected towards the Galactic bulge. Aims. One of the aims of the VISTA Variables in the Via Lactea (VVV) Survey is to accurately measure the physical parameters of the known globular clusters in the inner regions of the Milky Way and search for new ones, hidden in regions of large extinction. Methods. From deep near-infrared images, we derive deep JHK(S)-band photometry of a region surrounding the known globular cluster UKS 1 and reveal a new low-mass globular cluster candidate that we name VVV CL001. Results. We use the horizontal-branch red clump to measure E(B-V) similar to 2.2 mag, (m - M)(0) = 16.01 mag, and D = 15.9 kpc for the globular cluster UKS 1. On the basis of near-infrared colour-magnitude diagrams, we also find that VVV CL001 has E(B-V) similar to 2.0, and that it is at least as metal-poor as UKS 1, although its distance remains uncertain. Conclusions. Our finding confirms the previous projection that the central region of the Milky Way harbours more globular clusters. VVV CL001 and UKS 1 are good candidates for a physical cluster binary, but follow-up observations are needed to decide if they are located at the same distance and have similar radial velocities.

THE GEMINI NICI PLANET-FINDING CAMPAIGN: DISCOVERY OF A CLOSE SUBSTELLAR COMPANION TO THE YOUNG DEBRIS DISK STAR PZ Tel

We report the discovery of a tight substellar companion to the young solar analog PZ Tel, a member of the beta Pic moving group observed with high-contrast adaptive optics imaging as part of the Gemini Near-Infrared Coronagraphic Imager Planet-Finding Campaign. The companion was detected at a projected separation of 16.4 +/- 1.0 AU (0.'' 33 +/- 0.'' 01) in 2009 April. Second-epoch observations in 2010 May demonstrate that the companion is physically associated and shows significant orbital motion. Monte Carlo modeling constrains the orbit of PZ Tel B to eccentricities >0.6. The near-IR colors of PZ Tel B indicate a spectral type of M7 +/- 2 and thus this object will be a new benchmark companion for studies of ultracool, low-gravity photospheres. Adopting an age of 12(-4)(+8) Myr for the system, we estimate a mass of 36 +/- 6 M(Jup) based on the Lyon/DUSTY evolutionary models. PZ Tel B is one of the few young substellar companions directly imaged at orbital separations similar to those of giant planets in our own solar system. Additionally, the primary star PZ Tel A shows a 70 mu m emission excess, evidence for a significant quantity of circumstellar dust that has not been disrupted by the orbital motion of the companion.

Star formation in the intragroup medium and other diagnostics of the evolutionary stages of compact groups of galaxies

Context. Compact groups of galaxies are entities that have high densities of galaxies and serve as laboratories to study galaxy interactions, intergalactic star formation and galaxy evolution. Aims. The main goal of this study is to search for young objects in the intragroup medium of seven compact groups of galaxies: HCG 2, 7, 22, 23, 92, 100 and NGC 92 as well as to evaluate the stage of interaction of each group. Methods. We used Fabry-Perot velocity fields and rotation curves together with GALEX NUV and FUV images and optical R-band and HI maps. Results. (i) HCG 7 and HCG 23 are in early stages of interaction; (ii) HCG 2 and HCG 22 are mildly interacting; and (iii) HCG 92, HCG 100 and NGC 92 are in late stages of evolution. We find that all three evolved groups contain populations of young blue objects in the intragroup medium, consistent with ages < 100 Myr, of which several are younger than < 10 Myr. We also report the discovery of a tidal dwarf galaxy candidate in the tail of NGC 92. These three groups, besides containing galaxies that have peculiar velocity fields, also show extended HI tails. Conclusions. Our results indicate that the advanced stage of evolution of a group, together with the presence of intragroup HI clouds, may lead to star formation in the intragroup medium. A table containing all intergalactic HII regions and tidal dwarf galaxies confirmed to date is appended.

Pulsations in the late-type Be star HD 50 209 detected by CoRoT

Context. The presence of pulsations in late-type Be stars is still a matter of controversy. It constitutes an important issue to establish the relationship between non-radial pulsations and the mass-loss mechanism in Be stars. Aims. To contribute to this discussion, we analyse the photometric time series of the B8IVe star HD 50 209 observed by the CoRoT mission in the seismology field. Methods. We use standard Fourier techniques and linear and non-linear least squares fitting methods to analyse the CoRoT light curve. In addition, we applied detailed modelling of high-resolution spectra to obtain the fundamental physical parameters of the star. Results. We have found four frequencies which correspond to gravity modes with azimuthal order m = 0,-1,-2,-3 with the same pulsational frequency in the co-rotating frame. We also found a rotational period with a frequency of 0.679 cd(-1) (7.754 mu Hz). Conclusions. HD 50 209 is a pulsating Be star as expected from its position in the HR diagram, close to the SPB instability strip.

Possible evidence of asymmetry in SN 2007rt, a type IIn supernova

An optical photometric and spectroscopic analysis of the slowly-evolving type IIn SN 2007rt is presented, covering a duration of 481 days after discovery. Its earliest spectrum, taken approximately 100 days after the explosion epoch, indicates the presence of a dense circumstellar medium, with which the supernova ejecta is interacting. This is supported by the slowly-evolving light curve. A notable feature in the spectrum of SN 2007rt is the presence of a broad He I 5875 line, not usually detected in type IIn supernovae. This may imply that the progenitor star has a high He/H ratio, having shed a significant portion of its hydrogen shell via mass-loss. An intermediate resolution spectrum reveals a narrow H(alpha) P-Cygni profile, the absorption component of which has a width of 128 km s (1). This slow velocity suggests that the progenitor of SN 2007rt recently underwent mass-loss with wind speeds comparable to the lower limits of those detected in luminous blue variables. Asymmetries in the line profiles of H and He at early phases bears some resemblance to double-peaked features observed in a number of Ib/c spectra. These asymmetries may be indicative of an asymmetric or bipolar outflow or alternatively dust formation in the fast expanding ejecta. In addition, the late time spectrum, at over 240 days post-explosion, shows clear evidence for the presence of newly formed dust.

THE SLOAN BRIGHT ARCS SURVEY: DISCOVERY OF SEVEN NEW STRONGLY LENSED GALAXIES FROM z=0.66-2.94

We report the discovery of seven new, very bright gravitational lens systems from our ongoing gravitational lens search, the Sloan Bright Arcs Survey (SBAS). Two of the systems are confirmed to have high source redshifts z = 2.19 and z = 2.94. Three other systems lie at intermediate redshift with z = 1.33, 1.82, 1.93 and two systems are at low redshift z = 0.66, 0.86. The lensed source galaxies in all of these systems are bright, with i-band magnitudes ranging from 19.73 to 22.06. We present the spectrum of each of the source galaxies in these systems along with estimates of the Einstein radius for each system. The foreground lens in most systems is identified by a red sequence based cluster finder as a galaxy group; one system is identified as a moderately rich cluster. In total, SBAS has now discovered 19 strong lens systems in the SDSS imaging data, 8 of which are among the highest surface brightness z similar or equal to 2-3 galaxies known.

First discovery of a rare polygyne colony in the stingless bee Melipona quadrifasciata (Apidae, Meliponini)

FAPESP

Late Entry into HIV Care: Estimated Impact on AIDS Mortality Rates in Brazil, 2003-2006

Background: Worldwide, a high proportion of HIV-infected individuals enter into HIV care late. Here, our objective was to estimate the impact that late entry into HIV care has had on AIDS mortality rates in Brazil. Methodology/Principal Findings: We analyzed data from information systems regarding HIV-infected adults who sought treatment at public health care facilities in Brazil from 2003 to 2006. We initially estimated the prevalence of late entry into HIV care, as well as the probability of death in the first 12 months, the percentage of the risk of death attributable to late entry, and the number of avoidable deaths. We subsequently adjusted the annual AIDS mortality rate by excluding such deaths. Of the 115,369 patients evaluated, 50,358 (43.6%) had entered HIV care late, and 18,002 died in the first 12 months, representing a 16.5% probability of death in the first 12 months (95% CI: 16.3-16.7). By comparing patients who entered HIV care late with those who gained timely access, we found that the risk ratio for death was 49.5 (95% CI: 45.1-54.2). The percentage of the risk of death attributable to late entry was 95.5%, translating to 17,189 potentially avoidable deaths. Averting those deaths would have lowered the 2003-2006 AIDS mortality rate by 39.5%. Including asymptomatic patients with CD4(+) T cell counts >200 and <= 350 cells/mm(3) in the group who entered HIV care late increased this proportion by 1.8%. Conclusions/Significance: In Brazil, antiretroviral drugs reduced AIDS mortality by 43%. Timely entry would reduce that rate by a similar proportion, as well as resulting in a 45.2% increase in the effectiveness of the program for HIV care. The World Health Organization recommendation that asymptomatic patients with CD4(+) T cell counts <= 350 cells/mm(3) be treated would not have a significant impact on this scenario.

Late Pleistocene and Holocene vegetation changes in northeastern Brazil determined from carbon isotopes and charcoal records in soils

Northeastern Brazil represents a strategic area in terms of Quaternary records of environmental changes in South America due to its distinct semi-arid climate in near equatorial latitudes. In this study, carbon isotope and charcoal distribution records in soils are used to characterize vegetation dynamics, forest fires and their relation to climate change since the Late Pleistocene in the States of Ceara, Piaui and Paraiba, Northeastern Brazil. At the Ceara site, the carbon isotope record showed an enrichment trend from -24%(o) to 19%(o) during the early-mid Holocene, indicating an opening of vegetation and expansion of savanna vegetation (C(4) plants) during this period. A trend toward more depleted delta(13)C values (similar to-32%.) in the late Holocene indicates an expansion of forest vegetation (C(3) plants). A similar trend is observed at the Piaui and Paraiba sites where values of similar to-24%0 are associated with open forest vegetation during the late Pleistocene. In the early-mid Holocene, delta(13)C values of up to -18.0%(o), suggest the expansion of C4 plants. Based on the carbon isotope data, it is postulated that from similar to 18,000 cal yr B.P. to similar to 11,800 cal yr B.P.-similar to 10,000 cal yr B.P. arboreal vegetation was dominant in northeastern Brazil and is associated with humid climates. The savanna expanded from similar to 10,000 cal yr B.P. to similar to 4500-3200 cal yr B.P. due to a less humid/drier climatic phase, also supported by the significant presence of fires (charcoal fragments in the soil). From approximately 3200-2000 cal yr B.P. to the present, carbon isotope records suggest forest expansion and a more humid phase. These results form part of a regional pattern since they are in agreement with paleovegetation records obtained in regions of Maranhao, northeastern Brazil and in the Amazon and Rondonia States, northern Brazil. (C) 2010 Elsevier B.V. All rights reserved.