3,650 research outputs found
Weak Galactic Halo--Fornax dSph Connection from RR Lyrae Stars
For the first time accurate pulsation properties of the ancient variable
stars of the Fornax dwarf spheroidal galaxy (dSph) are discussed in the broad
context of galaxy formation and evolution. Homogeneous multi-band optical
photometry of spanning {\it twenty} years has allowed us to identify and
characterize more than 1400 RR Lyrae stars (RRLs) in this galaxy. Roughly 70\%
are new discoveries. We investigate the period-amplitude distribution and find
that Fornax shows a lack of High Amplitude (A_V\gsim0.75 mag) Short Period
fundamental-mode RRLs (P\lsim0.48 d, HASPs). These objects occur in stellar
populations more metal-rich than [Fe/H]-1.5 and they are common in the
Galactic halo (Halo) and in globulars. This evidence suggests that old (age
older than 10 Gyr) Fornax stars are relatively metal-poor.
A detailed statistical analysis of the role of the present-day Fornax dSph in
reproducing the Halo period distribution shows that it can account for only a
few to 20\% of the Halo when combined with RRLs in massive dwarf galaxies
(Sagittarius dSph, Large Magellanic Cloud). This finding indicates that
Fornax-like systems played a minor role in building up the Halo when compared
with massive dwarfs. We also discuss the occurrence of HASPs in connection with
the luminosity and the early chemical composition of nearby dwarf galaxies. We
find that, independently of their individual star formation histories, bright
(M_V\lsim-13.5 mag) galaxies have HASPs, whereas faint ones (M_V\gsim-11
mag) do not. Interestingly enough, Fornax belongs to a luminosity range
(--11M--13.5 mag) in which the occurrence of HASPs appears to be
correlated with the early star formation and chemical enrichment of the host
galaxy.Comment: 7 pages, 5 figures, A&A, accepte
Produção de dois clones de acerola (Malpighia glabra L.) sob diferentes regimes de irrigação.
Com uma area de mais de dois milhoes de hectares plantados com fruteiras , o Brasil ja foi o maior produtor mundial de frutas, estando hoje em segundo lugar. (...) Este trabalho tem como objetivo estudar a frequencia de irrigacao na performance produtiva de dois tipos delecionados de acerola, nas condicoes do litoral cearense. Estas plntas foram obtidas originariamente a partir de sementes coletadas por pesquisadores do CNPAT em 1989, na Fazenda CAJUBA, em Nova Soure, BA (...) Programa de adubacao e dosagens (em g/planta/ano) usadas no experimento de acerola na Estacao Experimental do Vale do Curu.bitstream/CNPAT-2010/5348/1/Ct-018.pd
Astrometric positions for 18 irregular satellites of giant planets from 23 years of observations
The irregular satellites of the giant planets are believed to have been
captured during the evolution of the solar system. Knowing their physical
parameters, such as size, density, and albedo is important for constraining
where they came from and how they were captured. The best way to obtain these
parameters are observations in situ by spacecrafts or from stellar occultations
by the objects. Both techniques demand that the orbits are well known. We aimed
to obtain good astrometric positions of irregular satellites to improve their
orbits and ephemeris. We identified and reduced observations of several
irregular satellites from three databases containing more than 8000 images
obtained between 1992 and 2014 at three sites (Observat\'orio do Pico dos Dias,
Observatoire de Haute-Provence, and European Southern Observatory - La Silla).
We used the software PRAIA (Platform for Reduction of Astronomical Images
Automatically) to make the astrometric reduction of the CCD frames. The UCAC4
catalog represented the International Celestial Reference System in the
reductions. Identification of the satellites in the frames was done through
their ephemerides as determined from the SPICE/NAIF kernels. Some procedures
were followed to overcome missing or incomplete information (coordinates,
date), mostly for the older images. We managed to obtain more than 6000
positions for 18 irregular satellites: 12 of Jupiter, 4 of Saturn, 1 of Uranus
(Sycorax), and 1 of Neptune (Nereid). For some satellites the number of
obtained positions is more than 50\% of what was used in earlier orbital
numerical integrations. Comparison of our positions with recent JPL ephemeris
suggests there are systematic errors in the orbits for some of the irregular
satellites. The most evident case was an error in the inclination of Carme.Comment: 9 pages, with 3 being online materia
Produtividade de genótipos de feijão comum com altos teores de ferro e zinco submetidos a deficit hídrico no Semiárido brasileiro.
bitstream/item/53786/1/BPD85.pd
Comportamento das cultivares de algodoeiro moco Gossypium hirsutum L.r. marie galante Hutch no Estado da Paraiba em 1978/1979.
bitstream/item/33327/1/COMPORTAMENTO-DAS-CULTIVARES.pd
Rice mutants and their responses to suboptimal temperatures in the early stages of development.
Made available in DSpace on 2017-11-02T09:03:03Z (GMT). No. of bitstreams: 1
ArianoEINHARDTetal.2017Ricemutantsandtheirresponsesto.pdf: 667742 bytes, checksum: 95da4bc61cd97816f786faed6d0503b8 (MD5)
Previous issue date: 2017-10-31bitstream/item/165876/1/Ariano-EINHARDT-et-al.-2017-Rice-mutants-and-their-responses-to.pd
Comprimento e diâmetro de frutos de tomate para processametno industrial sob lâminas de irrigação.
Trabalho 27
BRS Sarandi: A New Andropogon Gayanus Cultivar for Tropical Pastures
BRS Sarandi is adapted to low and medium fertility soils. It has a medium-high height, with a semi-erect growth habit and a high total number of tillers. The annual productivity of dry matter is 11 t ha-1, concentrated in the rainy season (90%). Of the total DM produced, 60% are leaves. The levels of crude protein (CP), in vitro dry matter digestibility (IVDMD), neutral detergent fiber (NDF) and acid detergent fiber (ADF) are, on average, 8.7, 56.5, 66.7 and 38.2%, respectively. . The average daily weight gain was 0.7 kg/head/day, the gain per was and 1.7 kg ha-1 day with no supplementation except for mineral salt. The weight gain per area (AG) reached 15 @/ha/year with an average stocking rate of 2.5 AU. BRS Sarandi was registered in the Brazilian Cultivar Registry (Registro Nacional de Cultivares - RNC/MAPA) and is protected in the National Cultivar Protection System (Sistema Nacional de Proteção de Cultivares - SNPC/MAPA)
Factors controlling spatio-temporal variation in carbon dioxide efflux from surface litter, roots, and soil organic matter at four rain forest sites in the eastern Amazon
[1] This study explored biotic and abiotic causes for spatio-temporal variation in soil respiration from surface litter, roots, and soil organic matter over one year at four rain forest sites with different vegetation structures and soil types in the eastern Amazon, Brazil. Estimated mean annual soil respiration varied between 13-17 t C ha(-1) yr(-1), which was partitioned into 0-2 t C ha(-1) yr(-1) from litter, 6-9 t C ha(-1) yr(-1) from roots, and 5-6 t C ha(-1) yr(-1) from soil organic matter. Litter contribution showed no clear seasonal change, though experimental precipitation exclusion over a one-hectare area was associated with a ten-fold reduction in litter respiration relative to unmodified sites. The estimated mean contribution of soil organic matter respiration fell from 49% during the wet season to 32% in the dry season, while root respiration contribution increased from 42% in the wet season to 61% during the dry season. Spatial variation in respiration from soil, litter, roots, and soil organic matter was not explained by volumetric soil moisture or temperature. Instead, spatial heterogeneity in litter and root mass accounted for 44% of observed spatial variation in soil respiration (p < 0.001). In particular, variation in litter respiration per unit mass and root mass accounted for much of the observed variation in respiration from litter and roots, respectively, and hence total soil respiration. This information about patterns of, and underlying controls on, respiration from different soil components should assist attempts to accurately model soil carbon dioxide fluxes over space and time
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