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.

Discovery of two distinct red clumps in NGC 419: a rare snapshot of a cluster at the onset of degeneracy

Colour-magnitude diagrams (CMDs) of the Small Magellanic Cloud (SMC) star cluster NGC 419, derived from Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) data, reveal a well-delineated secondary clump located below the classical compact red clump typical of intermediate-age populations. We demonstrate that this feature belongs to the cluster itself, rather than to the underlying SMC field. Then, we use synthetic CMDs to show that it corresponds very well to the secondary clump predicted to appear as a result of He-ignition in stars just massive enough to avoid e(-)-degeneracy settling in their H-exhausted cores. The main red clump instead is made of the slightly less massive stars which passed through e(-) degeneracy and ignited He at the tip of the red giant branch. In other words, NGC 419 is the rare snapshot of a cluster while undergoing the fast transition from classical to degenerate H-exhausted cores. At this particular moment of a cluster`s life, the colour distance between the main-sequence turn-off and the red clump(s) depends sensitively on the amount of convective core overshooting, Lambda(c). By coupling measurements of this colour separation with fits to the red clump morphology, we are able to estimate simultaneously the cluster mean age (1.35(-0.04)(+0.11) Gyr) and overshooting efficiency (Lambda(c) = 0.47(-0.04)(+0.14)). Therefore, clusters like NGC 419 may constitute important marks in the age scale of intermediate-age populations. After eye inspection of other CMDs derived from HST/ACS data, we suggest that the same secondary clump may also be present in the Large Magellanic Cloud clusters NGC 1751, 1783, 1806, 1846, 1852 and 1917.

Breeding of the Rufous-thighed Hawk (Accipiter erythronemius) in Argentina and Brazil

The Rufous-thighed, Hawk (Accipiter erythronemius) is a poorly-known, small raptor that dwells in forests and wooded savannas in south and eastern Brazil, Taraguay, eastern Bolivia, north and central Argentina, and Uruguay. We studied breeding biology and food habits of the Rufous-thighed Hawk from 1994 to 2007. We documented 14 breeding attempts recorded at nine nest sites in eight localities in Argentina and Brazil. Rufous-thighed Hawks were year-round residents at the study areas. The breeding season was c. 38 weeks long (June through March). Territorial behavior and courtship spanned for 22 weeks starting in mid June. Nest-building started in August. Nestlings were observed throughout December and into early January while fledglings were observed from late December through late March. Most nest sites were conifer plantations averaging 32.2 (SD = 10) years old, 12.6 ha (SD = 11.3) in size with trees averaging d 37.5 cm (SD = 13.5) of diameter at breast height. Nests were placed 20.2 m high (SD = 5.7), near the trunks of non-emergent conifers (Pinus sp. or Araucaria angustifolia). Nests were made of sticks, greater diameter averaging 48.8 cm (SD = 11.4), while nest depth averaged 23.3 cm (SD = 14). Prey items were birds (n = 49) ranging in size from c. 10 g [House Wren (Troglodytes, aedon)] to c. 140 g [White-tipped Dove (Leptotila verreauxi)]. Young started to chase birds at the age of 42-45 days in mid January. Adult males were primarily food providers but also aided in nest defense against other raptors. Females incubated, brooded, and fed young, and took leading roles in defense against humans. Rufous-thighed Hawks had unlined nests placed high in trees, and breeding season was markedly protracted.

Age-related changes in cerebellar phosphatase-1 reduce Na,K-ATPase activity

We evaluated whether changes in protein content and activity of PP-1 and PP-2A were the mechanism underneath the basal age-related reduction in alpha(2/3)-Na,K-ATPase activity in rats cerebella and whether this occurred through the cyclic GMP-PKG pathway. PP1 activity, but not its expression, increased with age, whereas PP-2 was not changed. The activity Of ot2/3-Na,K-ATPase varied with age. and there was a negative association between the PP-1 and alpha(2/3)-Na,K-ATPase activities. In young rats, the inhibition of PP-1 and PP-2A by okadaic acid (OA) increased in a dose-dependent manner alpha(1)- and alpha(2/3)-Na,K-ATPase, but had no effect on Mg-ATPase activity. A direct stimulation of PKG with 8-Br-cyclic GMP did not surmount the effect of OA. This analogue of cyclic GMP inhibited PP-1 activity only, indicating that at least part of the increase in alpha(1)- and alpha(2/3)-Na,K-ATPase activity induced by OA was mediated by the cyclic GMP-PKG-PP-1 cascade. Taking into account that PP1 inhibition increased alpha(2/3)-Na,K-ATPase activity, we propose that an age-related increase in PP-1 activity due to a decrease in cyclic GMP-PKG modulation plays a role for the age-related reduction of alpha(2/3)-Na,K-ATPase activity in rat cerebellum. (C) 2007 Elsevier Inc. All rights reserved.

Hospital-based Surveillance to Evaluate the Impact of Rotavirus Vaccination in Sao Paulo, Brazil

Background: Brazil implemented routine immunization with the human rotavirus vaccine, Rotarix, in 2006 and vaccination coverage reached 81% in 2008 in Sao Paulo. Our aim was to assess the impact of immunization on the incidence of severe rotavirus acute gastroenteritis (AGE). Methods: We performed a 5-year (2004-2008) prospective surveillance at a sentinel hospital in Sao Paulo, with routine testing for rotavirus in all children less than 5 years of age hospitalized with AGE. Genotypes of positive samples were determined by reverse transcription polymerase chain reaction. Results: During the study, 655 children hospitalized with AGE were enrolled; of whom 169 (25.8%) were positive for rotavirus. In the post-vaccine period, a 59% reduction in the number of hospitalizations of rotavirus AGE and a 42.2% (95% confidence interval [CI], 18.6%-59.0%; P = 0.001) reduction in the proportion of rotavirus-positive results among children younger than 5 years were observed, with the greatest decline among infants (69.2%; 95% CI, 24.7%-87.4%; P = 0.004). Furthermore, the number of all-cause hospitalizations for AGE was reduced by 29% among children aged <5 years. The onset and peak incidences of rotavirus AGE occurred 3 months later in the 2007 and 2008 seasons compared with previous years. Genotype G2 accounted for 15%, 70%, and 100% of all cases identified, respectively, in 2006, 2007, and 2008. Conclusions: After vaccine implementation, a marked decline in rotavirus AGE hospitalizations was demonstrated among children younger than 5 years of age, with the greatest reduction in the age groups targeted for vaccination. The predominance of genotype G2P[4] highlights the need of continued postlicensure surveillance studies.

Dating archeological ceramics from the Valley of Vitor, Arequipa by the TL method

The age of some ancient pottery from the Valley of Vitor in the region of Arequipa, Peru, is determined by the thermoluminescence (TL) method. For dating, a 325 degrees C TL peak was used and irradiation with -dose from 5 to 50Gy was carried out for the additive method, and from 0.4 to 5Gy for the regeneration method. For these dose values, the TL intensity is observed to grow linearly, obtaining an accumulated dose of 1.62 +/- 0.09Gy and 1.36 +/- 0.03Gy for the additive and regeneration methods, respectively. The age (A) of the sample was calculated by the two methods, being A=867 +/- 195 years after Christ (AC) for the additive method and A=1050 +/- 157 years AC for the regeneration method. Both results are within 800-1200 years AC, which is the period of the Wari culture.

Chemostratigraphy of the Tamengo Formation (Corumba Group, Brazil) A contribution to the calibration of the Ediacaran carbon-isotope curve

The Corumba Group cropping out in the southern Paraguay Belt in Brazil is one of the most complete Ediacaran sedimentary archives of palaeogeographic climatic biogeochemical and biotic evolution in southwestern Gondwana The unit hosts a rich fossil record including acritarchs vendotaenids (Vendo taenia Eoholynia) soft-bodied metazoans (Corumbella) and skeletal fossils (Cloudina Titanotheca) The Tamengo Formation made up mainly of limestones and marls provides a rich bio- and chemostratigraphic record Several outcrops formerly assigned to the Cuiaba Group are here included in the Tamengo Formation on the basis of lithological and chemostratigraphical criteria High-resolution carbon isotopic analyses are reported for the Tamengo Formation showing (from base to top) (1) a positive delta(13)C excursion to +4 parts per thousand PDB above post-glacial negative values (2) a negative excursion to -3 5 parts per thousand associated with a marked regression and subsequent transgression (3) a positive excursion to +5 5 parts per thousand and (4) a plateau characterized by delta(13)C around +3 parts per thousand A U-Pb SHRIMP zircon age of an ash bed Interbedded in the upper part of the delta(13)C positive plateau yielded 543 +/- 3 Ma which is considered as the depositional age (Babinski et al 2008a) The positive plateau in the upper Tamengo Formation and the preceding positive excursion are ubiquitous features in several successions worldwide including the Nama Group (Namibia) the Dengying Formation (South China) and the Nafun and Ara groups (Oman) This plateau is constrained between 542 and 551 Ma thus consistent with the age of the upper Tamengo Formation The negative excursion of the lower Tamengo Formation may be correlated to the Shuram-Wonoka negative anomaly although delta(13)C values do not fall beyond -3 5 parts per thousand in the Brazilian sections Sedimentary breccias occur just beneath this negative excursion in the lower Tamengo Formation One possible interpretation of the origin of these breccias is a glacioeustatic sea-level fall but a tectonic interpretation cannot be completely ruled out Published by Elsevier B V

Closing the Clymene ocean and bending a Brasiliano belt: Evidence for the Cambrian formation of Gondwana, southeast Amazon craton

We report new paleomagnetic and geochronological data from Ediacaran rift-drift carbonates in the Paraguai belt at the southern end of the suture zone between the Amazon craton and the Sao Francisco and Rio de Plata cratons, South America. Early thrusting resulted in remagnetization ca. 528 +/- 36 Ma or later; the mean age is established by (40)Ar/(39)Ar encapsulation dating of mixed authigenic and detrital illite from remagnetized carbonates from the unmetamorphosed fold-thrust belt. This remagnetization overlaps with a 525 Ma Gondwana reference pole. Metamorphic illite from the slate belt yields (40)Ar/(39)Ar ages of 496-484 Ma, the timing of peak regional metamorphism. Oroclinal bending of the Paraguai belt was caused by a 90 degrees clockwise rotation of the east-west limb after ca. 528 Ma, probably reflecting the irregular margin of the southeast Amazon craton. The age of the Paraguai belt overlaps with that of the Pampean orogeny farther south along the western margin of the Rio de Plata craton, suggesting a coeval closure for the Clymene ocean separating the Amazon craton from the Sao Francisco and Rio de Plata cratons.

Tectonic implications of a paleomagnetic study of the Sarmiento Ophiolitic Complex, southern Chile

A paleomagnetic study was carried out on the Late Jurassic Sarmiento Ophiolitic Complex (SOC) exposed in the Magallanes fold and thrust belt in the southern Patagonian Andes (southern Chile). This complex, mainly consisting of a thick succession of pillow-lavas, sheeted dikes and gabbros, is a seafloor remnant of the Late Jurassic to Early Cretaceous Rocas Verdes basin that developed along the south-western margin of South America. Stepwise thermal and alternating field demagnetization permitted the isolation of a post-folding characteristic remanence, apparently carried by fine grain (SD?) magnetite, both in the pillow-lavas and dikes. The mean ""in situ"" direction for the SOC is Dec: 286.9 degrees, Inc: -58.5 degrees, alpha-95: 6.9 degrees, N: 11 (sites). Rock magnetic properties, petrography and whole-rock K-Ar ages in the same rocks are interpreted as evidence of correlation between remanence acquisition and a greenschist facies metamorphic overprint that must have occurred during latest stages or after closure and tectonic inversion of the basin in the Late Cretaceous. The mean remanence direction is anomalous relative to the expected Late Cretaceous direction from stable South America. Particularly, a declination anomaly over 50 degrees is suggestively similar to paleomagnetically interpreted counter clockwise rotations found in thrust slices of the Jurassic El Quemado Fm. located over 100 km north of the study area in Argentina. Nevertheless, a significant ccw rotation of the whole SOC is difficult to reconcile with geologic evidence and paleogeographic models that suggest a narrow back-arc basin sub-parallel to the continental margin. A rigid-body 30 degrees westward tilting of the SOC block around a horizontal axis trending NNW, is considered a much simpler explanation, being consistent with geologic evidence. This may have occurred as a consequence of inverse reactivation of old normal faults, which limit both the SOC exposures and the Cordillera Sarmiento to the East. The age of tilting is unknown but it must postdate remanence acquisition in the Late Cretaceous. Two major orogenic events of the southern Patagonian Andes, in the Eocene (ca. 42 Ma) and Middle Miocene (ca. 12 Ma), respectively, could have caused the proposed tilting. (C) 2008 Elsevier B.V. All rights reserved.

Obsessive-compulsive disorder: Influence of age at onset on comorbidity patterns

Purpose. - This study investigates the influence of age at onset of OCS on psychiatric comorbidities, and tries to establish a cut-off point for age at onset. Methods. - Three hundred and thirty OCD patients were consecutively recruited and interviewed using the following structured interviews: Yale-Brown Obsessive Compulsive Scale; Yale Global Tic Severity Scale and the Structured Clinical Interview for DSM-IV. Data were analyzed with regression and cluster analysis. Results. - Lower age at onset was associated with a higher probability of having comorbidity with tic, anxiety, somatoform, eating and impulse-control disorders. Longer illness duration was associated with lower chance of having tics. Female gender was associated with anxiety, eating and impulse-control disorders. Tic disorders were associated with anxiety disorders and attention-deficit/hyperactivity disorder. No cutoff age at onset was found to clearly divide the sample in homogeneous subgroups. However, cluster analyses revealed that differences started to emerge at the age of 10 and were more pronounced at the age of 17, suggesting that these were the best cut-off points on this sample. Conclusions. - Age at onset is associated with specific comorbidity patterns in OCD patients. More prominent differences are obtained when analyzing age at onset as an absolute value. (C) 2008 Elsevier Masson SAS. All rights reserved.

The travel imagination and the hybrid reality in the wake of colonialism

The “traveling imagination,” is of paramount importance to both western and postcolonial travelers. Since both groups create “travel imaginations” by extensive reading, the nature of the books that inform them must directly affect their travels. A westerner, for example, who reads only colonial-era accounts has the “travel imagination” of a different generation. If all perspectives were represented equally in libraries, the “travel imagination” of a given person would be entirely his/her own. But usually the “traveler’s imagination” is biased by prevailing opinion. Libraries are not democracies, and sometimes extensive reading only indoctrinates the reader with the biases of the canon. Perhaps the following generalization will be helpful. Westerners are able to create “traveling imaginations,” based on the books they trust. But postcolonials, who have reason to be suspicious of what they read, have complicated “traveling imaginations.” Sometimes postcolonial travelers base their “traveling imaginations” on what they read, and sometimes, in opposition to what they read. The books discussed in this thesis, In Patagonia, The Cruise of the Shark, The Happy Isles of Oceania, A Passage to England and The Enigma of Arrival, were first published in, 1977, 1939, 1992, 1971 and 1987, respectively, in what Ali Behdad calls the “age of colonial dissolution.” Perhaps it would be more accurate to say these books are set in the “age of colonial demolition.” For the most part, the empires in these texts are in ruins, or at least in the process of being dismantled. In fact, two of the authors, Nirad Chaudhuri and V.S. Naipaul are canonical post-colonial thinkers.