Cromosomas y localizacion de Ag-NOR en poblaciones fluviales de Salmo trutta fario L. 1758 (Salmoniformes: Salmonidae) del Desierto de Atacama, Chile

Salmo trutta fario L. 1758, presented a chromosome number 2n = 80 and a fundamental number NF = 100. The haploid chromosome set consists of seven metacentric chromosomes, three submetacentric, one subtelocentric and 29 telocentrics. The Ag-NOR are located at conserved position in the short arm of pair 11 (st), with the presence of additional NOR on the short arm of pair 9 (sm) which is rare in others taxa previously studied.Salmo truttafario L. 1758, presenta un número cromosómico 2n=80 y un número fundamental NF=100. El juego cromosómico haploide está constituido por siete cromosomas metacéntricos, tres submetacéntricos, un subtelocéntrico y 29 telocéntricos. Los Ag-NOR se localizan en posición conservada en el brazo corto del par 11 (st), con la existencia de NOR adicionales en el brazo corto del par 9 (sm) el que es poco frecuente en otros taxa previamente estudiados

Thirty Meter Telescope Site Testing I: Overview

As part of the conceptual and preliminary design processes of the Thirty Meter Telescope (TMT), the TMT site testing team has spent the last five years measuring the atmospheric properties of five candidate mountains in North and South America with an unprecedented array of instrumentation. The site testing period was preceded by several years of analyses selecting the five candidates, Cerros Tolar, Armazones and Tolonchar in northern Chile; San Pedro Martir in Baja California, Mexico and the 13 North (13N) site on Mauna Kea, Hawaii. Site testing was concluded by the selection of two remaining sites for further consideration, Armazones and Mauna Kea 13N. It showed that all five candidates are excellent sites for an extremely large astronomical observatory and that none of the sites stands out as the obvious and only logical choice based on its combined properties. This is the first article in a series discussing the TMT site testing project.Comment: Accepted for publication in PASP, April 2009 issu

Exploring Halo Substructure with Giant Stars III: First Results from the Grid Giant Star Survey and Discovery of a Possible Nearby Sagittarius Tidal Structure in Virgo

We describe first results of a spectroscopic probe of selected fields from the Grid Giant Star Survey. Multifiber spectroscopy of several hundred stars in a strip of eleven fields along delta approximately -17^{circ}, in the range 12 <~ alpha <~ 17 hours, reveals a group of 8 giants that have kinematical characteristics differing from the main field population, but that as a group maintain coherent, smoothly varying distances and radial velocities with position across the fields. Moreover, these stars have roughly the same abundance, according to their MgH+Mgb absorption line strengths. Photometric parallaxes place these stars in a semi-loop structure, arcing in a contiguous distribution between 5.7 and 7.9 kpc from the Galactic center. The spatial, kinematical, and abundance coherence of these stars suggests that they are part of a diffuse stream of tidal debris, and one roughly consistent with a wrapped, leading tidal arm of the Sagittarius dwarf spheroidal galaxy.Comment: 8 pages including 4 figures. Accepted for publication in ApJ

Formation of SMBH seeds in Pop III star clusters through collisions : the importance of mass loss

Runaway collisions in dense clusters may lead to the formation of supermassive black hole (SMBH) seeds, and this process can be further enhanced by accretion, as recent models of SMBH seed formation in Population III star clusters have shown. This may explain the presence of supermassive black holes already at high redshift, $z>6$. However, in this context, mass loss during collisions was not considered and could play an important role for the formation of the SMBH seed. Here, we study the effect of mass loss, due to collisions of protostars, in the formation and evolution of a massive object in a dense primordial cluster. We consider both constant mass loss fractions as well as analytic models based on the stellar structure of the collision components. Our calculations indicate that mass loss can significantly affect the final mass of the possible SMBH seed. Considering a constant mass loss of 5% for every collision, we can lose between 60-80% of the total mass that is obtained if mass loss were not considered. Using instead analytical prescriptions for mass loss, the mass of the final object is reduced by 15-40%, depending on the accretion model for the cluster we study. Altogether, we obtain masses of the order of $10^4M_{\odot}$, which are still massive enough to be SMBH seeds.Comment: 12 pages, 9 figures, accepted by MNRA

Wide-Field Survey of Globular Clusters in M31. I. A Catalog of New Clusters

We present the result of a wide-field survey of globular clusters (GCs) in M31 covering a 3deg x 3deg field c. We have searched for GCs on CCD images taken with Washington CMT1 filters at the KPNO 0.9 m telescope using steps: (1) inspection of morphological parameters given by the SExtractor package such as stellarity, full maximum, and ellipticity; (2) consulting the spectral types and radial velocities obtained from spectra takena spectrograph at the WIYN 3.5 m telescope; and (3) visual inspection of the images of each object. We have and GC candidates, of which 605 are newly found GCs and GC candidates and 559 are previously known GCs. Amoects there are 113 genuine GCs, 258 probable GCs, and 234 possible GCs, according to our classification critee known objects there are 383 genuine GCs, 109 probable GCs, and 67 possible GCs. In total there are 496 genprobable GCs and 301 possible GCs. Most of these newly found GCs have T1 magnitudes of 17.5 - 19.5 mag, [17.9 < V < 19.9 mag assuming (C-T1) ~ 1.5], and (C-T1) colors in the range 1 - 2.Comment: accepted by AJ, using emulateapj.cl

Immune-mediated hookworm clearance and survival of a marine mammal decrease with warmer ocean temperatures

Indexación: Scopus.We appreciate the logistical support of the Chilean Navy, Artisanal fishermen of Quellon (Vessel crews Marimar II and Nautylus V), and the crews of the Chilean Navy lighthouse. We thank Amanda Hooper, Eugene DeRango, Elvira Vergara, Ignacio Silva, Dr. Lorraine Barbosa, Emma Milner, Sian Tarrant, Emily Morris, Suzette Miller, and Piero Becker for dedicated field assistance. We thank Dr. Vanesa Ezenwa for comments and insights in earlier versions of the manuscript. This work was supported by The Rufford Small Grant Foundation (Grant N 18815–1), Morris Animal Foundation (Grant N D16ZO-413), and the Society for Marine Mammalogy Small Grants in aid awards 2015 and 2016.Increases in ocean temperature are associated with changes in the distribution of fish stocks, and the foraging regimes and maternal attendance patterns of marine mammals. However, it is not well understood how these changes affect offspring health and survival. The maternal attendance patterns and immunity of South American fur seals were assessed in a rookery where hookworm disease is the main cause of pup mortality. Pups receiving higher levels of maternal attendance had a positive energy balance and a more reactive immune system. These pups were able to expel hookworms through a specific immune mediated mechanism and survived the infection. Maternal attendance was higher in years with low sea surface temperature, therefore, the mean hookworm burden and mortality increased with sea surface temperature over a 10-year period. We provide a mechanistic explanation regarding how changes in ocean temperature and maternal care affect infectious diseases dynamics in a marine mammal. © Seguel et al.https://elifesciences.org/articles/3843