522 research outputs found
Graptemys pseudogeographica
Number of Pages: 6Integrative BiologyGeological Science
Graptemys oculifera
Number of Pages: 2Integrative BiologyGeological Science
Graptemys
Number of Pages: 3Integrative BiologyGeological Science
Pseudemys alabamensis
Number of Pages: 2Integrative BiologyGeological Science
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Podocnemis sextuberculata
Number of pages: 24Geological SciencesIntegrative Biolog
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Trachemys adiutrix
Number of Pages: 4Integrative BiologyGeological Science
The CIV-MgII Kinematics Connection in <z>~0.7 Galaxies
We have examined Faint Object Spectrograph data from the Hubble Space
Telescope Archive for CIV 1548,1550 absorption associated with 40 MgII
2796,2803 absorption-selected galaxies at 0.4 < z < 1.4. We report a strong
correlation between MgII kinematics, measured in 6 km/s resolution HIRES/Keck
spectra, and W_r(1548); this implies a physical connection between the
processes that produce "outlying velocity" MgII clouds and high ionization
galactic/halo gas. We found no trend in ionization condition,
W_r(1548)/W_r(2796), with galaxy-QSO line-of-sight separation for 13 systems
with confirmed associated galaxies, suggesting no obvious ionization gradient
with galactocentric distance in these higher redshift galaxies. We find
tentative evidence (2-sigma) that W_r(1548)/W_r(2796) is anti-correlated with
galaxy color; if further data corroborate this trend, in view of the
strong CIV-MgII kinematics correlation, it could imply a connection between
stellar populations, star formation episodes, and the kinematics and ionization
conditions of halo gas at z~1.Comment: Accepted to Astrophysical Journal Letters; 4 pages; 3 figures;
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Las serpientes ponzoñosas de la reserva piagaçu-purus y accidentes ofídicos en la region baja de la cuenca del rio purús, amazonía central
Acidentes com serpentes peçonhentas são um problema de saúde pública que anualmente vitima 2.5 milhões de pessoas, no entanto, apenas recentemente foram considerados pela World Health Organization – WHO como uma doença amplamente negligenciada por países tropicais e subtropicais em desenvolvimento (WHO, 2009). Nestas regiões, estes eventos afetam principalmente a população rural em condições precárias de tratamento por antiveneno, acarretando altas taxas anuais de invalidez e mortalidade de cerca de 250 mil vítimas com seqüelas e 85 mil óbitos (WARREL, 2010; WHO, 2009). HARRISON et al. (2009) analisando dados de acidentes ofídicos para mais de uma centena de países demonstraram relação robusta das mortes com indicadores socioeconômicos de pobreza, encontrado associação negativa entre estas mortes e o gasto público com saúde. Na maior parte, os acidentes ofídicos acometem trabalhadores agrícolas no desempenho das atividades de subsistência, sendo uma doença ocupacional que impacta negativamente a produção de alimentos e conseqüentemente, a economia destes países (WARREL, 2010; HARRISON et al., 2009; WHO, 2009)
Estrutura populacional, tamanho e razão sexual de Podocnemis unifilis (Testudines, Podocnemididae) no rio Guaporé (RO), norte do Brasil
Population structure and sex ratio of Podocnemis unifilis was studied from June to November 1989 and from March to June 1990 in the Guaporé river and its tributaries São Domingos and São Miguel, in the municipality of Costa Marques, Rondônia, Brazil. The margins of these rivers are not altered much by human activities and the water is not polluted in any way. Turtles were captured using 12 fyke nets. Around 1 % of the captured turtles died using this method. The majority of the turtles was captured in the bays and oxbows (55.8%) and when the water level of the river was declining (N=785). The proportion of adults (73.4 %) in the sample was about three times higher than that of juveniles (26.6 %). The distribution of carapace length in males formed a normal curve, while that of females showed no well-defined pattern. The sex ratio of adults in this population was 9.8 males per female
Evolution of the Near-Infrared Tully-Fisher Relation: Constraints on the Relationship Between the Stellar and Total Masses of Disk Galaxies since z=1
Using a combination of Keck spectroscopy and near-infrared imaging, we
investigate the K-band and stellar mass Tully-Fisher relation for 101 disk
galaxies at 0.2 < z < 1.2, with the goal of placing the first observational
constraints on the assembly history of halo and stellar mass. Our main result
is a lack of evolution in either the K-band or stellar mass Tully-Fisher
relation from z = 0 - 1.2. Furthermore, although our sample is not
statistically complete, we consider it suitable for an initial investigation of
how the fraction of total mass that has condensed into stars is distributed
with both redshift and total halo mass. We calculate stellar masses from
optical and near-infrared photometry and total masses from maximum rotational
velocities and disk scale lengths, utilizing a range of model relationships
derived analytically and from simulations. We find that the stellar/total mass
distribution and stellar-mass Tully-Fisher relation for z > 0.7 disks is
similar to that at lower redshift, suggesting that baryonic mass is accreted by
disks along with dark matter at z < 1, and that disk galaxy formation at z < 1
is hierarchical in nature. We briefly discuss the evolutionary trends expected
in conventional structure formation models and the implications of extending
such a study to much larger samples.Comment: ApJ, in press, 9 page
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